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Sample records for 2mo sd 2y

  1. Thermodynamic stability of La2Mo2-yWyO9, La2Mo2-yWyO8.96+0.02y and La7Mo7(2-y)/2W7y/2O30 (y = 0, 0.5 and 1.0).

    PubMed

    Vega-Castillo, Jesús E; Ravella, Uday K; Corbel, Gwenaël; Lacorre, Philippe; Caneiro, Alberto

    2014-02-14

    The role of W content on the limit oxygen partial pressure (pO2) for stability of fast oxygen-ion conductors La2Mo2-yWyO9 with y = 0, 0.5 and 1.0 has been studied by means of thermogravimetric analysis (TGA) under controlled atmospheres. At 718 °C, below the pO2 stability limit of La2Mo2-yWyO9, the perovskite related compounds La7Mo7(2-y)/2W7y/2O30 were stabilized even for y = 1.0. At 608 °C, the first stage of reduction of β-La2Mo2-yWyO9 leads to the formation of the crystallized oxygen deficient La2Mo2-yWyO8.6+0.02y phase. X-ray powder diffraction shows that the stabilization of the high temperature β-form through tungsten substitution observed in fully oxidized La2Mo2-yWyO9 samples is preserved upon slight reduction. The n-type conductivity arising from the mixed valence state of molybdenum becomes less and less predominant as the W content increases. Further reduction causes amorphization. At both temperatures, W substitution does not enhance the thermodynamic stability of the La2Mo2-yWyO9 ion conductor under a reducing atmosphere but only slows down the kinetics of reduction. PMID:24336778

  2. Synthesis and Characterization of SiO2@Y2MoO6:Eu3+ Core-Shell Structured Spherical Phosphors by Sol-Gel Process.

    PubMed

    Li, G Z; Liu, F H; Chu, Z S; Wu, D M; Yang, L B; Li, J L; Wang, M N; Wang, Z L

    2016-04-01

    SiO2@Y2MoO6:Eu3+ core-shell phosphors were prepared by the sol-gel process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectra (EDS), transmission electron microscopy (TEM), photoluminescence (PL) spectra as well as kinetic decays were used to characterize the resulting SiO2@Y2MoO6:Eu3+ core-shell phosphors. The XRD results demonstrated that the Y2MoO6:Eu3+ layers on the SiO2 spheres crystallized after being annealed at 700 °C and the crystallinity increased with raising the annealing temperature. The obtained core-shell phosphors have spherical shape with narrow size distribution (average size ca. 640 nm), non-agglomeration, and smooth surface. The thickness of the Y2MoO6:Eu3+ shells on the SiO2 cores could be easily tailored by varying the number of deposition cycles (70 nm for four deposition cycles). The Eul+ shows a strong PL emission (dominated by 5D0-7F2 red emission at 614 nm) under the excitation of 347 nm UV light. The PL intensity of Eu3+ increases with increasing the annealing temperature and the number of coating cycles. PMID:27451737

  3. β-Nd2Mo4O15

    PubMed Central

    Zhao, Dan; Li, Fei-Fei; Yao, Yu-Ming; Huan, Chang-An; Zhao, En-Xiao

    2010-01-01

    The title compound, dineodymium(III) tetra­molybdate(VI), has been prepared by a flux technique and is the second polymorph of composition Nd2Mo4O15. The crystal structure is isotypic with those of Ce2Mo4O15 and Pr2Mo4O15. It features a three-dimensional network composed of distorted edge- and corner-sharing NdO7 polyhedra, NdO8 polyhedra, MoO4 tetra­hedra and MoO6 octa­hedra. PMID:21589208

  4. Negative thermal expansion in Y 2Mo 3O 12

    NASA Astrophysics Data System (ADS)

    Marinkovic, B. A.; Jardim, P. M.; de Avillez, R. R.; Rizzo, F.

    2005-11-01

    The crystal structure of Y 2Mo 3O 12 was refined by the Rietveld method for 130 °C as orthorhombic with space group Pbcn (No. 60). It is isostructural to Fe 2Mo 3O 12 and consists of vertex sharing YO 6 and MoO 4 building polyhedra. Y 2Mo 3O 12 has very high negative thermal expansion along all three crystallographic directions in the 130-900 °C temperature range. The overall linear coefficient of thermal expansion ( α=α/3) is -1.26×10 °C. Water molecules enter freely in Y 2Mo 3O 12 microchannels and seem to have a role in partial amorphization of this compound at room temperature.

  5. Preparation in Acidic and Alkaline Conditions and Characterization of α-Bi2Mo3O12 and γ-Bi2MoO6 Powders

    NASA Astrophysics Data System (ADS)

    Chen, Tao; Wang, Mao-Hua; Ma, Xiao-Yu

    2016-08-01

    α-Bi2Mo3O12 and γ-Bi2MoO6 powders have been successfully fabricated via a sol-gel method starting from bismuth nitrate and ammonium molybdate. The as-synthesized samples were characterized by x-ray powder diffraction analysis, thermogravimetry and differential thermogravimetry, scanning electron microscopy, and ultraviolet-visible (UV-Vis) absorption spectroscopy. The results indicated the formation of α-Bi2Mo3O12 and γ-Bi2MoO6 powders in acidic (pH 5) and alkaline (pH 9) conditions, respectively. α-Bi2Mo3O12 exhibited irregular shape, while γ-Bi2MoO6 showed approximately flake-like morphology. The bandgap of pure α-Bi2Mo3O12 and γ-Bi2MoO6 was estimated to be about 2.83 eV and 2.85 eV, respectively, according to UV-Vis studies. The slight shift of the absorption edge towards longer wavelength for α-Bi2Mo3O12 indicated a decrease of the optical bandgap. Photocatalytic experiments showed that γ-Bi2MoO6 exhibited higher photodegradation activity of methylene blue compared with α-Bi2Mo3O12.

  6. Preparation in Acidic and Alkaline Conditions and Characterization of α-Bi2Mo3O12 and γ-Bi2MoO6 Powders

    NASA Astrophysics Data System (ADS)

    Chen, Tao; Wang, Mao-Hua; Ma, Xiao-Yu

    2016-05-01

    α-Bi2Mo3O12 and γ-Bi2MoO6 powders have been successfully fabricated via a sol-gel method starting from bismuth nitrate and ammonium molybdate. The as-synthesized samples were characterized by x-ray powder diffraction analysis, thermogravimetry and differential thermogravimetry, scanning electron microscopy, and ultraviolet-visible (UV-Vis) absorption spectroscopy. The results indicated the formation of α-Bi2Mo3O12 and γ-Bi2MoO6 powders in acidic (pH 5) and alkaline (pH 9) conditions, respectively. α-Bi2Mo3O12 exhibited irregular shape, while γ-Bi2MoO6 showed approximately flake-like morphology. The bandgap of pure α-Bi2Mo3O12 and γ-Bi2MoO6 was estimated to be about 2.83 eV and 2.85 eV, respectively, according to UV-Vis studies. The slight shift of the absorption edge towards longer wavelength for α-Bi2Mo3O12 indicated a decrease of the optical bandgap. Photocatalytic experiments showed that γ-Bi2MoO6 exhibited higher photodegradation activity of methylene blue compared with α-Bi2Mo3O12.

  7. Na2MoO2As2O7

    PubMed Central

    Jouini, Raja; Zid, Mohamed Faouzi; Driss, Ahmed

    2012-01-01

    Disodium molybdenum dioxide diarsenate, Na2MoO2As2O7, has been synthesized by a solid-state reaction. The structure is built up from MoAs2O12 linear units sharing corners to form a three-dimensional framework containing tunnels running along the a-axis direction in which the Na+ cations are located. In this framework, the AsV atoms are tetra­hedrally coordinated and form an As2O7 group. The MoVI atom is displaced from the center of an octa­hedron of O atoms. Two Na+ cations are disordered about inversion centres. Structural relationships between different compounds: A 2MoO2As2O7 (A = K, Rb), AMOP2O7 (A = Na, K, Rb; M = Mo, Nb) and MoP2O7 are discussed. PMID:23468669

  8. SD46 Facilities and Capabilities

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    The displays for the Materials Conference presents some of the facilities and capabilities in SD46 that can be useful to a prospective researcher from University, Academia or other government labs. Several of these already have associated personnel as principal and co-investigators on NASA peer reviewed science investigations. 1. SCN purification facility 2. ESL facility 3. Static and Dynamic magnetic field facility 4. Microanalysis facility 5. MSG Investigation - PFMI 6. Thermo physical Properties Measurement Capabilities.

  9. Synthesis and investigation of uranyl molybdate UO2MoO4

    NASA Astrophysics Data System (ADS)

    Nagai, Takayuki; Sato, Nobuaki; Kitawaki, Shin-ichi; Uehara, Akihiro; Fujii, Toshiyuki; Yamana, Hajimu; Myochin, Munetaka

    2013-02-01

    In order to examine easily synthetic conditions of uranyl molybdate, UO2MoO4, used for the reprocessing process study of spent nuclear oxide fuels in alkaline molybdate melts, the uranium molybdate compounds were produced from U3O8 powder and anhydrous MoO3 reagent. The results of having investigated them in solid state by using X-ray diffractometry and Raman spectrometry, it was confirmed that UO2MoO4 could be synthesized by heating mixed powder of U3O8 and MoO3 with stoichiometric mole ratio at 770 °C for 4 h under air atmosphere. Moreover, adding this UO2MoO4 into Li2MoO4sbnd Na2MoO4 eutectic melt, most of the dissolved uranium species in the melt were observed as hexa-valent uranyl ions by absorption spectrophotometry.

  10. Redetermination of Zn2Mo3O8

    PubMed Central

    Cuny, Jerome; Gougeon, Patrick; Gall, Philippe

    2009-01-01

    The crystal structure of dizinc trimolybdenum(IV) octa­oxide, Zn2Mo3O8, has been redetermined from single-crystal X-ray data. The structure has been reported previously based on neutron powder diffraction data [Hibble et al. (1999 ▶). Acta Cryst. B55, 683-697] and single-crystal data [McCarroll et al. (1957 ▶). J. Am. Chem. Soc. 79, 5410–5414; Ansell & Katz (1966 ▶) Acta Cryst. 21, 482–485]. The results of the current redetermination show an improvement in the precision of the structural and geometric parameters with all atoms refined with anisotropic displacement parameters. The crystal structure consists of distorted hexa­gonal-close-packed oxygen layers with stacking sequence abac along [001] and is held together by alternating zinc and molybdenum layers. The Zn atoms occupy both tetra­hedral and octa­hedral inter­stices with a ratio of 1:1. The Mo atoms occupy octa­hedral sites and form strongly bonded triangular clusters involving three MoO6 octa­hedra that are each shared along two edges, forming a Mo3O13 unit. All atoms lie on special positions. The Zn atoms are in 2b Wyckoff positions with 3m. site symmetry, the Mo atoms are in 6c Wyckoff positions with . m. site symmetry and the O atoms are in 2a, 2b and 6c Wyckoff positions with 3m. and . m. site symmetries, respectively. PMID:21582645

  11. Consolidated Fleet N2Y-1

    NASA Technical Reports Server (NTRS)

    1930-01-01

    Consolidated Fleet N2Y-1: The Consolidated Fleet N2Y-1 aircraft were used as trainers for the pilots who would fly the 'parasite' fighters attached to the airships Akron and Macon. This N2Y-1 was turned over to the NACA for research work. Note that the vertical surfaces are instrumented for NACA work. This N2Y was used for landing gear tests.

  12. Partial substitution of Mo{sup 6+} by S{sup 6+} in the fast oxide ion conductor La{sub 2}Mo{sub 2}O{sub 9}: Synthesis, structure and sulfur depletion

    SciTech Connect

    Mhadhbi, Noureddine; Corbel, Gwenaeel; Lacorre, Philippe; Bulou, Alain

    2012-06-15

    Powder-solid state reaction route using La{sub 2}(SO{sub 4}){sub 3} as sulfur source was used to prepare compositions of the solid solution La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9}. Single phases were only obtained in the substitution range extending up to y=0.8 (40 mol% S) at the annealing temperature of 850 Degree-Sign C with regard to the limit of stability of the lanthanum sulphate reactant. Within the synthesis conditions, a stabilization of the high temperature {beta}-form is observed from and above y=0.1 (5 mol% S). Temperature-controlled X-ray diffraction and thermogravimetric analyses have shown that La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9} raw powders undergo thermal decompositions in two steps. Heating above 900 Degree-Sign C, a sulfur depletion to the benefit of molybdenum in La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9} raw powders leads to the formation of La{sub 2}SO{sub 6}. At higher temperature, the exsolved La{sub 2}SO{sub 6} phase then decomposes into La{sub 2}O{sub 3}, which in turn reacts with the sulfur-depleted La{sub 2}Mo{sub 2}O{sub 9} phase to form La{sub 2}MoO{sub 6}. The present study also reveals that depending on the substitution rate y, the sulfur depletion can be induced by ball-milling of raw powders. Along the La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9} series, the isovalent substitution of molybdenum by sulfur tends to restrict in magnitude, or even to suppress above 400 Degree-Sign C, the distortive thermal expansion of the cubic {beta}-type structure, thus strongly decreasing the conductance at high temperature. - Graphical abstract: La{sub 2}O{sub 3}-MoO{sub 3}-'SO{sub 3}' ternary phase diagram showing the exsolution path at low temperature (white arrows) and the total decomposition path at high temperature (black arrows) of {beta}-La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9} raw powders. Highlights: Black-Right-Pointing-Pointer Isovalent substitution of molybdenum by sulfur in La{sub 2}Mo{sub 2}O{sub 9} up to 40 mol%. Black

  13. Efficient Charge Separation between Bi and Bi2 MoO6 for Photoelectrochemical Properties.

    PubMed

    Ma, Ying; Jia, Yulong; Wang, Lina; Yang, Min; Bi, Yingpu; Qi, Yanxing

    2016-04-18

    Herein, porous Bi/Bi2 MoO6 nanoparticles have been prepared by a facile in-situ reduction approach. Moreover, the morphology and Bi content of product could be controlled by varying the reaction time. By controlled fabrication, the desired porous Bi2 MoO6 nanostructure with incorporation of Bi was obtained and exhibited high photoelectric and photocatalytic activity. In particular, the samples yield a photocurrent density of 320 μA cm(-2) , which is 3.2 times that of the pure Bi2 MoO6 nanosheet (100 μA cm(-2) ) under the same conditions. UV/Vis diffuse reflectance spectroscopy analysis confirmed the surface plasmon resonance in the as-prepared porous nanoparticles. The improved photoelectric properties could be the synergistic effect of the porous structure with large surface area and effective electron-hole separations between Bi and Bi2 MoO6 . PMID:26868192

  14. Reduction Kinetics of La2Mo2O9 and Phase Evolution during Reduction and Reoxidation.

    PubMed

    Buvat, Gaëtan; Sellemi, Houssem; Ravella, Uday K; Barré, Maud; Coste, Sandrine; Corbel, Gwenaël; Lacorre, Philippe

    2016-03-01

    An amorphous reduced form of oxide ion conductor La2Mo2O9 had been proposed as sulfur-tolerant anode material for solid oxide fuel cell, but its oxygen content was not known. In this paper, we investigate the reduction kinetics by diluted hydrogen of La2Mo2O9 to amorphous, and the oxygen range of the amorphous form. The reduction kinetics is studied as a function of the powder specific surface area and of the temperature, on powders synthesized by solid state reaction and by polyol process using two different solvents. The reduction process was carried out by TGA under 10% H2 diluted in argon, and its kinetics is analyzed and modeled. As expected, small particles and high temperature lead to higher reduction rates. Several reduction steps were identified by XRD during the process. At 700 °C La2Mo2O9 is directly reduced into the amorphous phase La2Mo2O7-y, whereas at 760 °C reduction occurs through an intermediate crystallized La7Mo7O30 (≅ La2Mo2O8.57) phase before amorphization. In both cases, further reduction of La2Mo2O6.2 amorphous phase leads to an exsolution of metallic molybdenum and a molybdenum deficiency in the amorphous phase. Reoxidation of amorphous La2Mo2O7-y was studied by TGA, DTA and XRD. At low temperature in air, the reduced compounds are reoxidized while remaining amorphous. The annealing for 60 h at 350 °C in air of reduced La2Mo2O6.66, obtained beforehand by solid state reaction, gives an amorphous phase with composition La2Mo2O8.85. The existence domain of the reduced amorphous phase in terms of oxygen content therefore ranges at least from O6.2 to O8.85, thus including the composition La2Mo2O8.50 of the amorphous surface layer at the origin of a huge increase of ionic conductivity recently reported in nanowires of La2Mo2O9. PMID:26910206

  15. The Consolidated Fleet XN2Y-1

    NASA Technical Reports Server (NTRS)

    1935-01-01

    The Consolidated Fleet XN2Y-1 was a Fleet 1 trainer purchased by the Navy for evaluation. The purchase of several N2Y-1 aircraft followed, for use as trainers for the pilots who would fly the 'parasite' fighters attached to the airships Akron and Macon. The XN2Y-1 was turned over to the NACA for research work. Note the that vertical surfaces are instrumented for NACA spin work.

  16. A WSe{sub 2}/MoSe{sub 2} heterostructure photovoltaic device

    SciTech Connect

    Flöry, Nikolaus; Jain, Achint; Bharadwaj, Palash; Parzefall, Markus; Novotny, Lukas; Taniguchi, Takashi; Watanabe, Kenji

    2015-09-21

    We report on the photovoltaic effect in a WSe{sub 2}/MoSe{sub 2} heterojunction, demonstrating gate tunable current rectification with on/off ratios of over 10{sup 4}. Spatially resolved photocurrent maps show the photovoltaic effect to originate from the entire overlap region. Compared to WSe{sub 2}/MoS{sub 2} heterostructures, our devices perform better at long wavelengths and yield higher quantum efficiencies, in agreement with Shockley-Queisser theory.

  17. The SD oscillator and its attractors

    NASA Astrophysics Data System (ADS)

    Cao, Q.; Wiercigroch, M.; Pavlovskaia, E.; Grebogi, C.; Michael, J.; Thompson, T.

    2008-02-01

    We propose a new archetypal oscillator for smooth and discontinuous systems (SD oscillator). This oscillator behaves both smooth and discontinuous system depending on the value of the smoothness parameter. New dynamic behaviour is presented for the transitions from the smooth to discontinuous regime.

  18. NDPC-SD Data Probes Worksheet

    ERIC Educational Resources Information Center

    National Dropout Prevention Center for Students with Disabilities, 2011

    2011-01-01

    This worksheet from the National Dropout Prevention Center for Students with Disabilities (NDPC-SD) is an optional tool to help schools organize multiple years of student and program data for the purpose of identifying school-completion needs that can be addressed through the implementation of research-based interventions. It is designed for use…

  19. Synthesis, crystal structure and pseudocapacitor electrode properties of γ-Bi2MoO6 nanoplates

    NASA Astrophysics Data System (ADS)

    Senthilkumar, Baskar; Selvan, Ramakrishnan Kalai; Vasylechko, Leonid; Minakshi, Manickam

    2014-09-01

    Nanoplate-like bismuth molybdates (γ-Bi2MoO6) is prepared for the first time by urea assisted solution combustion synthesis (SCS) and studied the structural and electrochemical properties to explore the possibility of using as negative electrodes in pseudocapacitors. The formation of single phase γ-Bi2MoO6 and plate-like morphology is revealed from XRD Rietveld refinement and FESEM, respectively. The pseudocapacitive behaviour of γ-Bi2MoO6 is analyzed by cyclic voltammetry and galvanostatic charge-discharge techniques. The effect of Na based aqueous electrolytes on capacitance of the Aurvillius type structured Bi2MoO6 is investigated. As prepared γ-Bi2MoO6 nanoplates provide the high specific capacitance (519 F g-1) compared with the high-temperature monoclinic phase γ(H) Bi2MoO6 in 1 M NaOH electrolyte. The obtained high specific capacitance of as prepared Bi2MoO6 could be attributed to the decrease in particle size, increase in active sites, and nanoplate-like structure of as prepared γ-Bi2MoO6.

  20. Superatomic crystal emerging in transition-metal oxides: Molybdenum hollandite K2Mo8O16

    NASA Astrophysics Data System (ADS)

    Toriyama, T.; Watanabe, M.; Konishi, T.; Ohta, Y.

    2013-12-01

    Density-functional-theory-based electronic structure calculations are carried out to elucidate the origins of the observed electronic properties of molybdenum hollandite K2Mo8O16. We find that the Mo4 cluster in the double Mo chains behaves as a "superatom," a hypothetical big atom with a single composite molecular orbital, and that the system can be regarded as a solid of the superatoms condensed into a simple monoclinic structure with four superatoms per unit cell, thereby yielding four energy bands near the Fermi level at half filling. Based on an effective model proposed, we argue that K2Mo8O16 is a Mott insulator with one electron per superatom, which exhibits strongly frustrated antiferromagnetic spin correlations in the superatomic crystal.

  1. Emergent Honeycomb Lattice in LiZn2Mo3O8

    NASA Astrophysics Data System (ADS)

    Flint, Rebecca; Lee, Patrick A.

    2013-11-01

    We introduce the idea of emergent lattices, where a simple lattice decouples into two weakly coupled lattices as a way to stabilize spin liquids. In LiZn2Mo3O8, the disappearance of 2/3 of the spins at low temperatures suggests that its triangular lattice decouples into an emergent honeycomb lattice weakly coupled to the remaining spins, and we suggest several ways to test this proposal. We show that these orphan spins act to stabilize the spin liquid in the J1-J2 honeycomb model and also discuss a possible 3D analogue, Ba2MoYO6 that may form a “depleted fcc lattice.”

  2. Highly transparent Bi2MoO6- and Bi2WO6-polymer nanocomposites.

    PubMed

    Wollmann, P; Grothe, J; Ziegler, C; Kaskel, S

    2011-04-01

    A combined method of precipitation, phase transfer into organic solvent, solvothermal treatment and subsequent in situ polymerization was used to integrate nanocrystalline Bi2MoO6- and Bi2WO6-particles into a polymer matrix of poly-laurylacrylate. The presented method offers a new and gentle way to produce highly transparent bulk nanocomposites containing evenly distributed Bi2MoO6- and Bi2WO6-nanoparticles. Characterization results of DLS-, XRD-, REM- and TEM-measurements are presented as well as solid state UV/VIS-measurements of the particles. The transparent nanocomposites were characterized using UV/VIS-spectroscopy and ellipsometry. All composites show a good transmission in the range from 800-400 nm. The particle content of the nanocomposites was measured with TG-measurements. PMID:21776724

  3. Attapulgite-CeO2/MoS2 ternary nanocomposite for photocatalytic oxidative desulfurization

    NASA Astrophysics Data System (ADS)

    Li, Xiazhang; Zhang, Zuosong; Yao, Chao; Lu, Xiaowang; Zhao, Xiaobing; Ni, Chaoying

    2016-02-01

    Novel attapulgite(ATP)-CeO2/MoS2 ternary nanocomposites were synthesized by microwave assisted assembly method. The structures of the nanocomposites were characterized by XRD, FT-IR, UV-vis, XPS and in situ TEM. The photocatalytic activities of ATP-CeO2/MoS2 composites were investigated by degradating dibenzothiophene (DBT) in gasoline under visible light irradiation. The effect of the mass ratio of CeO2 to MoS2 on photocatalytic activity was investigated. The results indicate that the three-dimensional network structure is firmly constructed by ATP skeleton, CeO2 particles and MoS2 nanosheet which effectively increase the surface area of the composites and promote the separation of electrons and holes by resulting electronic transmission channels of multi-channel in space. The degradation rate of DBT can reach 95% under 3 h irradiation when the mass ratio of CeO2/MoS2 is 4/10. A plausible mechanism for the photocatalytic oxidative desulfurization of this nanocomposite is put forward.

  4. Ferromagnetic superexchange in insulating Cr2MoO6 by controlling orbital hybridization

    DOE PAGESBeta

    Zhu, M.; Do, D.; Dela Cruz, Clarina R.; Dun, Zhiling; Cheng, J. -G.; Goto, H.; Uwatoko, Yoshiya; Zou, T.; Zhou, Haidon D.; Mahanti, Subhendra D.; et al

    2015-09-11

    We report the magnetic and electronic structures of the newly synthesized inverse-trirutile compound Cr2MoO6. Despite the same crystal symmetry and similar bond-lengths and bond-angles to Cr2TeO6, Cr2MoO6 possesses a magnetic structure of the Cr2MoO6 type, different from that seen in Cr2TeO6. Ab-initio electronic structure calculations show that the sign and strength of the Cr-O-Cr exchange coupling is strongly influenced by the hybridization between Mo 4d and O 2p orbitals. This result further substantiates our recently proposed mechanism for tuning the exchange interaction between two magnetic atoms by modifying the electronic states of the non-magnetic atoms in the exchange path throughmore » orbital hybridization. This approach is fundamentally different from the conventional methods of controlling the exchange interaction by either carrier injection or through structural distortions.« less

  5. Experimental study of upper sd shell nuclei and evolution of sd-fp shell gap

    SciTech Connect

    Sarkar, M. Saha

    2012-06-27

    The intruder orbitals from the fp shell play important role in the structure of nuclei around the line of stability in the upper sd shell. Experimentally we have studied {sup 35}Cl, {sup 30}P, {sup 36}Cl, {sup 37}Ar and {sup 34}Cl in this mass region using the INGA setup. Large basis cross-shell shell model calculations have indicated the need for change of the sd-fp energy gap for reliable reproduction of negative parity and high spin positive parity states. Indication of population of states of large deformation has been found in our data. Theoretical interpretation of these states has been discussed.

  6. Understanding nuclei in the upper sd - shell

    SciTech Connect

    Sarkar, M. Saha; Bisoi, Abhijit; Ray, Sudatta; Kshetri, Ritesh; Sarkar, S.

    2014-08-14

    Nuclei in the upper-sd shell usually exhibit characteristics of spherical single particle excitations. In the recent years, employment of sophisticated techniques of gamma spectroscopy has led to observation of high spin states of several nuclei near A ≃ 40. In a few of them multiparticle, multihole rotational states coexist with states of single particle nature. We have studied a few nuclei in this mass region experimentally, using various campaigns of the Indian National Gamma Array setup. We have compared and combined our empirical observations with the large-scale shell model results to interpret the structure of these nuclei. Indication of population of states of large deformation has been found in our data. This gives us an opportunity to investigate the interplay of single particle and collective degrees of freedom in this mass region.

  7. Phase formation in the Li2MoO4-K2MoO4-In2(MoO4)3 system and crystal structures of new compounds K3InMo4O15 and LiK2In(MoO4)3

    NASA Astrophysics Data System (ADS)

    Khal'baeva, Klara M.; Solodovnikov, Sergey F.; Khaikina, Elena G.; Kadyrova, Yuliya M.; Solodovnikova, Zoya A.; Basovich, Olga M.

    2012-03-01

    XRD study of solid-phase interaction in the Li2MoO4-K2MoO4-In2(MoO4)3 system was performed. The boundary K2MoO4-In2(MoO4)3 system is an non-quasibinary join of the K2O-In2O3-MoO3 system where a new polymolybdate K3InMo4O15 isotypic to K3FeMo4O15 was found. In the structure (а=33.2905(8), b=5.8610(1), c=15.8967(4) Å, β=90.725(1)°, sp. gr. C2/c, Z=8, R(F)=0.0407), InO6 octahedra, Mo2O7 diortho groups and MoO4 tetrahedra form infinite ribbons {[In(MoO4)2(Mo2O7)]3-}∞ along the b-axis. Between the chains, 8- to 10-coordinate potassium cations are located. A subsolidus phase diagram of the Li2MoO4-K2MoO4-In2(MoO4)3 system was constructed and a novel triple molybdate LiK2In(MoO4)3 was revealed. Its crystal structure (a=7.0087(2), b=9.2269(3), c=10.1289(3) Å, β=107.401(1)°, sp. gr. P21, Z=2, R(F)=0.0280) contains an open framework of vertex-shared MoO4 tetrahedra, InO6 octahedra and LiO5 tetragonal pyramids with nine- and seven-coordinate potassium ions in the framework channels.

  8. Indented Cu2MoS4 nanosheets with enhanced electrocatalytic and photocatalytic activities realized through edge engineering.

    PubMed

    Chen, Bang-Bao; Ma, De-Kun; Ke, Qing-Ping; Chen, Wei; Huang, Shao-Ming

    2016-03-01

    Edges often play a role as active centers for catalytic reactions in some nanomaterials. Therefore it is highly desirable to enhance catalytic activity of a material through modulating the microstructure of the edges. However, the study associated with edge engineering is less investigated and still at its preliminary stage. Here we report that Cu2MoS4 nanosheets with indented edges can be fabricated through a simple chemical etching route at room temperature, using Cu2MoS4 nanosheets with flat ones as sacrifice templates. Taking the electrocatalytic hydrogen evolution reaction (HER), photocatalytic degradation of rhodamine B (RhB) and conversion of benzyl alcohol as examples, the catalytic activity of Cu2MoS4 indented nanosheets (INSs) obtained through edge engineering was comparatively studied with those of Cu2MoS4 flat nanosheets (FNSs) without any modification. The photocatalytic tests revealed that the catalytic active sites of Cu2MoS4 nanosheets were associated with their edges rather than basal planes. Cu2MoS4 INSs were endowed with larger electrochemically active surface area (ECSA), more active edges and better hydrophilicity through the edge engineering. As a result, the as-fabricated Cu2MoS4 INSs exhibited an excellent HER activity with a small Tafel slope of 77 mV dec(-1), which is among the best records for Cu2MoS4 catalysts. The present work demonstrated the validity of adjusting catalytic activity of the material through edge engineering and provided a new strategy for designing and developing highly efficient catalysts. PMID:26876693

  9. Ab initio calculation of mechanical and thermal properties of U2Mo intermetallic

    NASA Astrophysics Data System (ADS)

    Jaroszewicz, S.; Losada, E. L.; Garcés, J. E.; Mosca, H. O.

    2013-10-01

    We present a study of structural, elastic and thermodynamic properties of tetragonal (C11b) U2Mo by means of density-functional theory based calculations using full-potential linearized augmented plane wave method. In this approach the generalized gradient approximation were used for the exchange-correlation potential calculation. The optimized lattice parameters are in excellent agreement with the experimental data. Through the Debye-Grüneisen model the temperature and pressure dependence of equation of state, bulk modulus, thermal expansion and specific heat have been obtained and discussed in the range of pressure 0-20 GPa and the temperature 0-800 K.

  10. Mechanism of corrosion of Ni base superalloys by molten Na2MoO4 at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Misra, A. K.; Stearns, C. A.

    1983-01-01

    The corrosion of nickel base superalloy, U-700, by molten Na2MoO4 was studied in the temperature range of 750 deg to 950 deg C. After an induction period, the rate of corrosion is linear and catastrophic corrosion is observed. It is shown that the induction period is associated with the attainment of a minimum MoO3 activity in the melt, which corresponds to the equilibrium MoO3 activity for the reaction, 2MoO3(l) + Mo = 3MoO2(s). A mechanism is proposed to describe the catastrophic nature of corrosion, which involves transport of Ni++ through the melt resulting in formulation of NiO at the melt gas interface and basic fluxing of Cr2O3. The effect of the amount of Na2MoO4 on the corrosion kinetics was also studied. It is found that evaporation and the thermodynamic calculations for the Na2MoO4 - MoO3 system the activity of MoO3 is reduced considerably when dissolved in Na2MoO4, which causes a sharp decrease in the rate of evaporation of MoO3 from a Na2MoO4 - MoO3 melt.

  11. Final report of the safety assessment of Alcohol Denat., including SD Alcohol 3-A, SD Alcohol 30, SD Alcohol 39, SD Alcohol 39-B, SD Alcohol 39-C, SD Alcohol 40, SD Alcohol 40-B, and SD Alcohol 40-C, and the denaturants, Quassin, Brucine Sulfate/Brucine, and Denatonium Benzoate.

    PubMed

    2008-01-01

    Alcohol Denat. is the generic term used by the cosmetics industry to describe denatured alcohol. Alcohol Denat. and various specially denatured (SD) alcohols are used as cosmetic ingredients in a wide variety of products. Many denaturants have been previously considered, on an individual basis, as cosmetic ingredients by the Cosmetic Ingredient Review (CIR) Expert Panel, whereas others, including Brucine and Brucine Sulfate, Denatonium Benzoate, and Quassin, have not previously been evaluated. Quassin is a bitter alkaloid obtained from the wood of Quassia amara. Quassin has been used as an insect antifeedant and insecticide and several studies demonstrate its effectiveness. At oral doses up to 1000 mg/kg using rats, Quassin was not toxic in acute and short-term tests, but some reversible piloerection, decrease in motor activity, and a partial loss of righting reflex were found in mice at 500 mg/kg. At 1000 mg/kg given intraperitoneally (i.p.), all mice died within 24 h of receiving treatment. In a cytotoxicity test with brine shrimp, 1 mg/ml of Quassin did not possess any cytotoxic or antiplasmodial activity. Quassin administered to rat Leydig cells in vitro at concentrations of 5-25 ng/ml inhibited both the basal and luteinizing hormone (LH)-stimulated testosterone secretion in a dose-related fashion. Quassin at doses up to 2.0 g/kg in drinking water using rats produced no significant effect on the body weights, but the mean weights of the testes, seminal vesicles, and epididymides were significantly reduced, and the weights of the anterior pituitary glands were significantly increased. The sperm counts and levels of LH, follicle-stimulating hormone (FSH), and testosterone were significantly lower in groups treated with Quassin. Brucine is a derivative of 2-hydroxystrychnine. Swiss-Webster mice given Brucine base, 30 ml/kg, had an acute oral LD(50) of 150 mg/kg, with central nervous system depression followed by convulsions and seizures in some cases. In those

  12. Suppressed phase transition and giant ionic conductivity in La2Mo2O9 nanowires

    PubMed Central

    Liu, Wei; Pan, Wei; Luo, Jian; Godfrey, Andy; Ou, Gang; Wu, Hui; Zhang, Wei

    2015-01-01

    Improving the ionic conductivity of solid electrolytes at low temperatures represents a major challenge and an opportunity for enabling a variety of solid-state ionic devices for energy conversion and storage, as well as for environmental protection. Here we report a giant ionic conductivity of 0.20 Scm−1, achieved at 500 °C, in the La2Mo2O9 nanowires with a bamboo-wire morphology, corresponding to a 1000-fold enhancement in conductivity over conventional bulk material. Stabilization of the high-temperature phase is observed to account for about a 10-fold increase in the conductivity. We further demonstrate that fast surface conduction in ∼3 nm thick, partially ordered, surface ‘amorphous' films, under strain on the curved surfaces of the nanowires (as a non-autonomous surface phase or complexion), contributes to an enhancement of the conductivity by another two orders of magnitude. Exemplified here by the study of the La2Mo2O9 nanowires, new possibilities for improvement of conductivity and for miniaturization of solid-state ionic devices by the careful use of one-dimensional nanomaterials can be envisioned. PMID:26380943

  13. Pressure-induced transition in Tl{sub 2}MoO{sub 4}

    SciTech Connect

    Machon, Denis; Friese, Karen; Breczewski, Tomasz; Grzechnik, Andrzej

    2010-11-15

    Tl{sub 2}MoO{sub 4} has been studied under high-pressure by X-ray diffraction, Raman spectroscopy, and optical absorption measurements. A first-order phase transition is observed at 3.5{+-}0.5 GPa. The nature (ordered vs. disordered) of the high-pressure phase strongly depends on the local hydrostatic conditions. Optical absorption measurements tend to show that this transition is concomitant with an electronic structure transformation. Prior to the transition, single crystal X-ray diffraction shows that pressure induces interactions between MoO{sub 4} fragments and the Mo coordination number tends to increase. In addition, the stereoactivity of the lone-pair electrons on the three symmetrically independent Tl-sites is not uniform; while for two sites the stereoactivity decreases with increasing pressures for the third site the stereoactivity increases. - Graphical Abstract: (up) Structural evolutions of Tl{sub 2}MoO{sub 4} in the low-pressure phase. (Down) Optical properties of the high-pressure phase as a function of pressure. Display Omitted

  14. Polymorphism in yttrium molybdate Y{sub 2}Mo{sub 3}O{sub 12}

    SciTech Connect

    Gates, Stacy D.; Lind, Cora

    2007-12-15

    Yttrium molybdate (Y{sub 2}Mo{sub 3}O{sub 12}) has been prepared by non-hydrolytic sol-gel chemistry. The phase evolution upon heating was investigated using in situ and ex situ heat treatments combined with powder X-ray diffraction. This method has led to the isolation of two orthorhombic phases with different atomic connectivity. Yttrium adopts 6- and 7-coordinate sites in the Pbcn and Pba2 structures, respectively. Cocrystallization of both phases was observed in a narrow temperature range, suggesting that crystallization kinetics play a major role in phase formation. It was found that the Pba2 phase is the stable polymorph below 550 deg. C, and converts to Pbcn at higher temperatures. - Graphical abstract: Yttrium molybdate (Y{sub 2}Mo{sub 3}O{sub 12}) prepared by non-hydrolytic sol-gel chemistry crystallizes in a mixture of orthorhombic polymorphs with different atomic connectivities. The Pbcn and Pba2 phases coexist over a narrow temperature range. Crystallization of the Pbcn structure is kinetically favored. The Pba2 polymorph is the thermodynamically stable phase at low temperatures, and converts to Pbcn above 550 deg. C.

  15. Pressure induced magnetic and semiconductor–metal phase transitions in Cr2MoO6

    NASA Astrophysics Data System (ADS)

    San-Dong, Guo

    2016-05-01

    We investigate magnetic ordering and electronic structures of Cr2MoO6 under hydrostatic pressure. To overcome the band gap problem, the modified Becke and Johnson exchange potential is used to investigate the electronic structures of Cr2MoO6. The insulating nature at the experimental crystal structure is produced, with a band gap of 1.04 eV, and the magnetic moment of the Cr atom is 2.50 μ B, compared to an experimental value of about 2.47 μ B. The calculated results show that an antiferromagnetic inter-bilayer coupling–ferromagnetic intra-bilayer coupling to a ferromagnetic inter-bilayer coupling–antiferromagnetic intra-bilayer coupling phase transition is produced with the pressure increasing. The magnetic phase transition is simultaneously accompanied by a semiconductor–metal phase transition. The magnetic phase transition can be explained by the Mo–O hybridization strength, and ferromagnetic coupling between two Cr atoms can be understood by empty Mo-d bands perturbing the nearest O-p orbital. Project supported by the Fundamental Research Funds for the Central Universities, China (Grant No. 2015XKMS073).

  16. Credit WCT. Original 2Y4" x 2Y4" color negative is housed ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Credit WCT. Original 2-Y4" x 2-Y4" color negative is housed in the JPL Photography Laboratory, Pasadena, California. JPL staff members Harold Anderson and John Morrow cast grain from the 1-gallon BakerPerkins model 4-PU mixer. A 1-pint Baker-Perkins model 2-PX mixer stands to the left in this view (JPL negative no. JPL-10295BC, 27 January 1989) - Jet Propulsion Laboratory Edwards Facility, Mixer & Casting Building, Edwards Air Force Base, Boron, Kern County, CA

  17. Novel soft-chemistry route of Ag2Mo3O10·2H2O nanowires and in situ photogeneration of a Ag@Ag2Mo3O10·2H2O plasmonic heterostructure.

    PubMed

    Hakouk, Khadija; Deniard, Philippe; Lajaunie, Luc; Guillot-Deudon, Catherine; Harel, Sylvie; Wang, Zeyan; Huang, Baibiao; Koo, Hyun-Joo; Whangbo, Myung-Hwan; Jobic, Stéphane; Dessapt, Rémi

    2013-06-01

    Ultrathin Ag2Mo3O10·2H2O nanowires (NWs) were synthesized by soft chemistry under atmospheric pressure from a hybrid organic-inorganic polyoxometalate (CH3NH3)2[Mo7O22] and characterized by powder X-ray diffraction, DSC/TGA analyses, FT-IR and FT-Raman spectroscopies, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Their diameters are a few tens of nanometers and hence much thinner than that found for silver molybdates commonly obtained under hydrothermal conditions. The optical properties of Ag2Mo3O10·2H2O NWs before and after UV irradiation were investigated by UV-vis-NIR diffuse reflectance spectroscopy revealing, in addition to photoreduction of Mo(6+) to Mo(5+) cations, in situ photogeneration of well-dispersed silver Ag(0) nanoparticles on the surface of the NWs. The resulting Ag@Ag2Mo3O10·2H2O heterostructure was confirmed by electron energy-loss spectroscopy (EELS), X-ray photoelectron spectroscopy (XPS), and Auger spectroscopy. Concomitant reduction of Mo(6+) and Ag(+) cations under UV excitation was discussed on the basis of electronic band structure calculations. The Ag@Ag2Mo3O10·2H2O nanocomposite is an efficient visible-light-driven plasmonic photocatalyst for degradation of Rhodamine B dye in aqueous solution. PMID:23679344

  18. Antipsychotic Drugs Inhibit Platelet Aggregation via P2Y1 and P2Y12 Receptors

    PubMed Central

    Wu, Chang-Chieh; Tsai, Fu-Ming; Chen, Mao-Liang; Wu, Semon; Lee, Ming-Cheng; Tsai, Tzung-Chieh; Wang, Lu-Kai; Wang, Chun-Hua

    2016-01-01

    Antipsychotic drugs (APDs) used to treat clinical psychotic syndromes cause a variety of blood dyscrasias. APDs suppress the aggregation of platelets; however, the underlying mechanism remains unknown. We first analyzed platelet aggregation and clot formation in platelets treated with APDs, risperidone, clozapine, or haloperidol, using an aggregometer and rotational thromboelastometry (ROTEM). Our data indicated that platelet aggregation was inhibited, that clot formation time was increased, and that clot firmness was decreased in platelets pretreated with APDs. We also examined the role two major adenosine diphosphate (ADP) receptors, P2Y1 and P2Y12, play in ADP-mediated platelet activation and APD-mediated suppression of platelet aggregation. Our results show that P2Y1 receptor stimulation with ADP-induced calcium influx was inhibited by APDs in human and rats' platelets, as assessed by in vitro or ex vivo approach, respectively. In contrast, APDs, risperidone and clozapine, alleviated P2Y12-mediated cAMP suppression, and the release of thromboxane A2 and arachidonic acid by activated platelets decreased after APD treatment in human and rats' platelets. Our data demonstrate that each APD tested significantly suppressed platelet aggregation via different mechanisms. PMID:27069920

  19. Theoretical study of hydration in Y2Mo3O12: Effects on structure and negative thermal expansion

    NASA Astrophysics Data System (ADS)

    Wu, Ming-Yi; Wang, Lei; Jia, Yu; Guo, Zheng-Xiao; Sun, Qiang

    2015-02-01

    We report ab-initio calculations of water absorption in Y2Mo3O12. The absorption geometry of H2O in Y2Mo3O12 and the binding property between H2O and Y2Mo3O12 have been first identified. Our calculated results show that water is chemisorbed in Y2Mo3O12 with O of the water binding to the Y3+ cation, which is further strengthened by hydrogen bonding between each of the hydrogen atoms of H2O and the bridge O in Y2Mo3O12, shared by polyhedrons YO6 and MoO4. The absorption of water leads to a reduced angle of Y-O-Mo and shortened Y-Mo distance, and consequently volume contraction of the material, almost linearly with the increasing number of water molecules per unit cell, up to eight in total. In addition, our phonon calculation show that the transverse vibration of Y-O-Mo is restricted due to water absorption, which in turn hinders the NTE, as it is mainly originated from this vibrational mode. Our results clarify further the fundamental mechanisms of the large volume shrinkage and the lost NTE of the framework oxide due to water absorption.

  20. Photoluminescence properties of a new orange-red emitting Sm3+-doped Y2Mo4O15 phosphor

    NASA Astrophysics Data System (ADS)

    Deng, Huajuan; Zhao, Ze; Wang, Jing; Hei, Zhoufei; Li, Mengxue; Noh, Hyeon Mi; Jeong, Jung Hyun; Yu, Ruijin

    2015-08-01

    A series of novel Y2Mo4O15:xSm3+ ((0.01 ≤ x ≤ 0.20) phosphors for white light-emitting (W-LEDs) were successfully prepared by the solid state reaction technology at 973 K for 12 h. X-ray diffraction and photoluminescence spectra were utilized to characterize the structure and luminescence properties of the as-synthesized phosphors. The emission spectra of the Y2Mo4O15:Sm3+ phosphors consisted of some sharp emission peaks of Sm3+ ions centered at 565 nm, 605 nm, 650 nm, and 712 nm. The strongest one is located at 605 nm due to 4G5/2-6H7/2 transition of Sm3+, generating bright orange-red light. The optimum dopant concentration of Sm3+ ions in Y2Mo4O15:xSm3+ is around 5 mol% and the critical transfer distance of Sm3+ is calculated as 23.32 Å. The CIE chromaticity coordinates of the Y2Mo4O15:0.05Sm3+ phosphors were located in the orange reddish region. The Y2Mo4O15:Sm3+ phosphors may be potentially used as red phosphors for white light-emitting diodes.

  1. Oxidation and embrittlement of Ti-6Al-2Sn-4Zr-2Mo alloy

    NASA Technical Reports Server (NTRS)

    Shenoy, R. N.; Unnam, J.; Clark, R.K.

    1986-01-01

    A thermogravimetric analysis monitoring study has been conducted for Ti-6Al-2Sn-4Zr-2Mo in the 593-760 C range, with a view to its total oxidation kinetics in laboratory air. In addition, tensile elongation was obtained for selected foil specimens after their exposure to simulated Space Shuttle reentry conditions. The total weight gain with time exhibited two parabolic stages separated by a transient region which is the result of a simultaneous increase in the parabolic growth rate constant for the oxide and in oxygen solubility at the oxide-metal interface. A model for the total oxidation kinetics accounting for the two individual components (oxide growth and solid solution formation) is proposed; the activation energy for oxygen diffusion in the alpha-solid solution is shown to approximate the activation energy for the degradation of tensile elongation of the alloy in its foil gage condition.

  2. Development of a Li2MoO4 scintillating bolometer for low background physics

    NASA Astrophysics Data System (ADS)

    Cardani, L.; Casali, N.; Nagorny, S.; Pattavina, L.; Piperno, G.; Barinova, O. P.; Beeman, J. W.; Bellini, F.; Danevich, F. A.; Di Domizio, S.; Gironi, L.; Kirsanova, S. V.; Orio, F.; Pessina, G.; Pirro, S.; Rusconi, C.; Tomei, C.; Tretyak, V. I.; Vignati, M.

    2013-10-01

    We present the performance of a 33 g Li2MoO4 crystal working as a scintillating bolometer. The crystal was tested for more than 400 h in a dilution refrigerator installed in the underground laboratory of Laboratori Nazionali del Gran Sasso (Italy). This compound shows promising features in the frame of neutron detection, dark matter search (solar axions) and neutrinoless double-beta decay physics. Low temperature scintillating properties were investigated by means of different α, β/γ and neutron sources, and for the first time the Light Yield for different types of interacting particle is estimated. The detector shows great ability of tagging fast neutron interactions and high intrinsic radiopurity levels ( < 90 μBq/kg for 238U and < 110 μBq/kg for 232Th).

  3. AgNa2Mo3O9AsO4

    PubMed Central

    Hamza, Hamadi; Zid, Mohamed Faouzi; Driss, Ahmed

    2011-01-01

    The title compound, silver disodium trimolybdenum(VI) nonaoxide arsenate, AgNa2Mo3O9AsO4, was prepared by a solid-state reaction at 808 K. The structure consists of an infinite (Mo3AsO13)n ribbon, parallel to the c axis, composed of AsO4 tetra­hedra and MoO6 octa­hedra sharing edges and corners. The Na and Ag ions partially occupy several independent close positions, with various occupancies, in the inter-ribbon space delimited by the one-dimensional framework. The composition was refined to Ag1.06(1)Na1.94(1)Mo3O9AsO4. PMID:22219728

  4. Two-Step Growth of Two-Dimensional WSe2/MoSe2 Heterostructures.

    PubMed

    Gong, Yongji; Lei, Sidong; Ye, Gonglan; Li, Bo; He, Yongmin; Keyshar, Kunttal; Zhang, Xiang; Wang, Qizhong; Lou, Jun; Liu, Zheng; Vajtai, Robert; Zhou, Wu; Ajayan, Pulickel M

    2015-09-01

    Two dimensional (2D) materials have attracted great attention due to their unique properties and atomic thickness. Although various 2D materials have been successfully synthesized with different optical and electrical properties, a strategy for fabricating 2D heterostructures must be developed in order to construct more complicated devices for practical applications. Here we demonstrate for the first time a two-step chemical vapor deposition (CVD) method for growing transition-metal dichalcogenide (TMD) heterostructures, where MoSe2 was synthesized first and followed by an epitaxial growth of WSe2 on the edge and on the top surface of MoSe2. Compared to previously reported one-step growth methods, this two-step growth has the capability of spatial and size control of each 2D component, leading to much larger (up to 169 μm) heterostructure size, and cross-contamination can be effectively minimized. Furthermore, this two-step growth produces well-defined 2H and 3R stacking in the WSe2/MoSe2 bilayer regions and much sharper in-plane interfaces than the previously reported MoSe2/WSe2 heterojunctions obtained from one-step growth methods. The resultant heterostructures with WSe2/MoSe2 bilayer and the exposed MoSe2 monolayer display rectification characteristics of a p-n junction, as revealed by optoelectronic tests, and an internal quantum efficiency of 91% when functioning as a photodetector. A photovoltaic effect without any external gates was observed, showing incident photon to converted electron (IPCE) efficiencies of approximately 0.12%, providing application potential in electronics and energy harvesting. PMID:26237631

  5. Two-step growth of two-dimensional WSe2/MoSe2 heterostructures

    DOE PAGESBeta

    Gong, Yongji; Lei, Sidong; Lou, Jun; Liu, Zheng; Vajtai, Robert; Zhou, Wu; Ajayan, Pullikel M.; Ye, Gonglan; Li, Bo; He, Yongmin; et al

    2015-08-03

    Two dimensional (2D) materials have attracted great attention due to their unique properties and atomic thickness. Although various 2D materials have been successfully synthesized with different optical and electrical properties, a strategy for fabricating 2D heterostructures must be developed in order to construct more complicated devices for practical applications. Here we demonstrate for the first time a two-step chemical vapor deposition (CVD) method for growing transition-metal dichalcogenide (TMD) heterostructures, where MoSe2 was synthesized first and followed by an epitaxial growth of WSe2 on the edge and on the top surface of MoSe2. Compared to previously reported one-step growth methods, thismore » two-step growth has the capability of spatial and size control of each 2D component, leading to much larger (up to 169 μm) heterostructure size, and cross-contamination can be effectively minimized. Furthermore, this two-step growth produces well-defined 2H and 3R stacking in the WSe2/MoSe2 bilayer regions and much sharper in-plane interfaces than the previously reported MoSe2/WSe2 heterojunctions obtained from one-step growth methods. The resultant heterostructures with WSe2/MoSe2 bilayer and the exposed MoSe2 monolayer display rectification characteristics of a p-n junction, as revealed by optoelectronic tests, and an internal quantum efficiency of 91% when functioning as a photodetector. As a result, a photovoltaic effect without any external gates was observed, showing incident photon to converted electron (IPCE) efficiencies of approximately 0.12%, providing application potential in electronics and energy harvesting.« less

  6. Thermal, vibrational, and thermoelastic properties of Y2Mo3O12 and their relations to negative thermal expansion

    NASA Astrophysics Data System (ADS)

    Romao, Carl P.; Miller, Kimberly J.; Johnson, Michel B.; Zwanziger, J. W.; Marinkovic, Bojan A.; White, Mary Anne

    2014-07-01

    Y2Mo3O12, a material that exhibits negative thermal expansion (NTE) from 10 to 1173 K, offers an excellent opportunity to examine relationships between NTE and other physical properties over a wide temperature range. We report experimental heat capacity, thermal conductivity, and elastic properties of Y2Mo3O12, as well as results of an ab initio study of the lattice dynamics, and show how the anomalously high heat capacity and low thermal conductivity are correlated with NTE. We also report the ab initio elastic tensor and experimental velocity of sound of Y2Mo3O12 and use it to calculate the thermal stresses in a simulated polycrystal using finite-element analysis, showing that elastic anisotropy and thermal expansion anisotropy couple to influence the properties of the bulk solid.

  7. P2Y Receptors Sensitize Mouse and Human Colonic Nociceptors

    PubMed Central

    Hockley, James R. F.; Tranter, Michael M.; McGuire, Cian; Boundouki, George; Cibert-Goton, Vincent; Thaha, Mohamed A.; Blackshaw, L. Ashley; Michael, Gregory J.; Baker, Mark D.; Knowles, Charles H.; Winchester, Wendy J.

    2016-01-01

    Activation of visceral nociceptors by inflammatory mediators contributes to visceral hypersensitivity and abdominal pain associated with many gastrointestinal disorders. Purine and pyrimidine nucleotides (e.g., ATP and UTP) are strongly implicated in this process following their release from epithelial cells during mechanical stimulation of the gut, and from immune cells during inflammation. Actions of ATP are mediated through both ionotropic P2X receptors and metabotropic P2Y receptors. P2X receptor activation causes excitation of visceral afferents; however, the impact of P2Y receptor activation on visceral afferents innervating the gut is unclear. Here we investigate the effects of stimulating P2Y receptors in isolated mouse colonic sensory neurons, and visceral nociceptor fibers in mouse and human nerve-gut preparations. Additionally, we investigate the role of Nav1.9 in mediating murine responses. The application of UTP (P2Y2 and P2Y4 agonist) sensitized colonic sensory neurons by increasing action potential firing to current injection and depolarizing the membrane potential. The application of ADP (P2Y1, P2Y12, and P2Y13 agonist) also increased action potential firing, an effect blocked by the selective P2Y1 receptor antagonist MRS2500. UTP or ADP stimulated afferents, including mouse and human visceral nociceptors, in nerve-gut preparations. P2Y1 and P2Y2 transcripts were detected in 80% and 56% of retrogradely labeled colonic neurons, respectively. Nav1.9 transcripts colocalized in 86% of P2Y1-positive and 100% of P2Y2-positive colonic neurons, consistent with reduced afferent fiber responses to UTP and ADP in Nav1.9−/− mice. These data demonstrate that P2Y receptor activation stimulates mouse and human visceral nociceptors, highlighting P2Y-dependent mechanisms in the generation of visceral pain during gastrointestinal disease. SIGNIFICANCE STATEMENT Chronic visceral pain is a debilitating symptom of many gastrointestinal disorders. The activation of

  8. Molecular mechanisms of platelet P2Y(12) receptor regulation.

    PubMed

    Cunningham, Margaret R; Nisar, Shaista P; Mundell, Stuart J

    2013-02-01

    Platelets are critical for haemostasis, however inappropriate activation can lead to the development of arterial thrombosis, which can result in heart attack and stroke. ADP is a key platelet agonist that exerts its actions via stimulation of two surface GPCRs (G-protein-coupled receptors), P2Y(1) and P2Y(12). Similar to most GPCRs, P2Y receptor activity is tightly regulated by a number of complex mechanisms including receptor desensitization, internalization and recycling. In the present article, we review the molecular mechanisms that underlie P2Y(1) and P2Y(12) receptor regulation, with particular emphasis on the structural motifs within the P2Y(12) receptor, which are required to maintain regulatory protein interaction. The implications of these findings for platelet responsiveness are also discussed. PMID:23356287

  9. P2Y1 and P2Y12 receptors for ADP desensitize by distinct kinase-dependent mechanisms.

    PubMed

    Hardy, Adam R; Conley, Pamela B; Luo, Jiansong; Benovic, Jeffrey L; Poole, Alastair W; Mundell, Stuart J

    2005-05-01

    Adenosine 5'-diphosphate (ADP) plays a central role in regulating platelet function by the activation of the G protein-coupled receptors P2Y(1) and P2Y(12). Although it is well established that aggregation responses of platelets to ADP desensitize, the underlying mechanisms involved remain unclear. In this study we demonstrate that P2Y(1)- and P2Y(12)-mediated platelet responses desensitize rapidly. Furthermore, we have established that these receptors desensitize by different kinase-dependent mechanisms. G protein-coupled receptor kinase (GRK) 2 and GRK6 are both endogenously expressed in platelets. Transient overexpression of dominant-negative mutants of these kinases or reductions in endogenous GRK expression by the use of specific siRNAs in 1321N1 cells showed that P2Y(12), but not P2Y(1), desensitization is mediated by GRKs. In contrast, desensitization of P2Y(1), but not P2Y(12), is largely dependent on protein kinase C activity. This study is the first to show that both P2Y(1) and P2Y(12) desensitize in human platelets, and it reveals ways in which their sensitivity to ADP may be differentially and independently altered. PMID:15665114

  10. User's Manual for Space Debris Surfaces (SD_SURF)

    NASA Technical Reports Server (NTRS)

    Elfer, N. C.

    1996-01-01

    A unique collection of computer codes, Space Debris Surfaces (SD_SURF), have been developed to assist in the design and analysis of space debris protection systems. SD_SURF calculates and summarizes a vehicle's vulnerability to space debris as a function of impact velocity and obliquity. An SD_SURF analysis will show which velocities and obliquities are the most probable to cause a penetration. This determination can help the analyst select a shield design which is best suited to the predominant penetration mechanism. The analysis also indicates the most suitable parameters for development or verification testing. The SD_SURF programs offer the option of either FORTRAN programs and Microsoft EXCEL spreadsheets and macros. The FORTRAN programs work with BUMPERII version 1.2a or 1.3 (Cosmic released). The EXCEL spreadsheets and macros can be used independently or with selected output from the SD_SURF FORTRAN programs.

  11. Hydrothermal synthesis and photocatalytic performance of hierarchical Bi{sub 2}MoO{sub 6} microspheres using BiOI microspheres as self-sacrificing templates

    SciTech Connect

    Xu, Ming; Zhang, Wei-De

    2015-07-15

    Bi{sub 2}MoO{sub 6} hierarchical microspheres were successfully prepared through phase transformation from BiOI microspheres with the assistance of sodium citrate under hydrothermal condition. The possible formation mechanism for the conversion of BiOI to Bi{sub 2}MoO{sub 6} is discussed here. After being annealed at 300 °C for 2 h, the obtained Bi{sub 2}MoO{sub 6} microspheres exhibited remarkably enhanced photocatalytic activity towards the degradation of rhodamine B and phenol. The superior catalytic performance can be attributed to its larger surface area and higher crystallinity. In addition, Bi{sub 2}MoO{sub 6} microspheres are stable during the degradation reaction and can be used repeatedly. - Graphical abstract: Bi{sub 2}MoO{sub 6} hierarchical microspheres were successfully prepared through a facile partial anion exchange strategy using BiOI microspheres as self-sacrificing templates. The Bi{sub 2}MoO{sub 6} microspheres show high visible light photocatalytic activity. - Highlights: • Bi{sub 2}MoO{sub 6} microspheres were prepared via self-sacrificing template anion exchange. • Sodium citrate-assisted anion exchange for preparation of Bi{sub 2}MoO{sub 6} photocatalyst. • Bi{sub 2}MoO{sub 6} catalysts show high visible light photocatalytic activity.

  12. Extending the family of oxygen ion conductors isostructural with La{sub 2}Mo{sub 2}O{sub 9}

    SciTech Connect

    Voronkova, V.I.; Kharitonova, E.P.; Orlova, E.I.; Belov, D.A.

    2012-12-15

    X-ray diffraction characterization of materials prepared by solid-state reactions in the ternary systems La{sub 2}Mo{sub 2}O{sub 9}-Nd{sub 2}W{sub 2}O{sub 9}-'Nd{sub 2}Mo{sub 2}O{sub 9}{sup '} and La{sub 2}Mo{sub 2}O{sub 9}-Pr{sub 2}W{sub 2}O{sub 9}-Pr{sub 2}Mo{sub 2}O{sub 9} has shown that, in these systems, compounds isostructural with the oxygen ion conductor La{sub 2}Mo{sub 2}O{sub 9} exist in wide single-phase regions. Partial tungsten substitution for molybdenum may yield stable Ln{sub 2}Mo{sub 2-2x}W{sub 2x}O{sub 9} compounds with the La{sub 2}Mo{sub 2}O{sub 9} structure, where Ln is a rare-earth element different from lanthanum and praseodymium, e.g., neodymium. Tungsten also stabilizes Pr{sub 2}Mo{sub 2}O{sub 9}, which otherwise decomposes above 700 Degree-Sign C. A series of continuous solid solution was found in the La{sub 2}Mo{sub 2}O{sub 9}-Pr{sub 2}Mo{sub 2}O{sub 9} system. Polymorphism of compounds existing in the above ternary systems was studied by differential scanning calorimetry. The conductivity of most of the compounds studied approaches that of lanthanum molybdate. - Graphical abstract: La{sub 2}Mo{sub 2}O{sub 9}-Nd{sub 2}W{sub 2}O{sub 9}-''Nd{sub 2}Mo{sub 2}O{sub 9}'' and La{sub 2}Mo{sub 2}O{sub 9}-Pr{sub 2}W{sub 2}O{sub 9}-Pr{sub 2}Mo{sub 2}O{sub 9} phase diagrams. Single-phase regions of compounds with the La{sub 2}Mo{sub 2}O{sub 9} and Nd{sub 2}W{sub 2}O{sub 9} (Pr{sub 2}W{sub 2}O{sub 9}) structures are highlighted in blue and red. Highlights: Black-Right-Pointing-Pointer Phase formation in the La{sub 2}Mo{sub 2}O{sub 9}-Pr{sub 2}W{sub 2}O{sub 9}-Pr{sub 2}Mo{sub 2}O{sub 9} system has been studied. Black-Right-Pointing-Pointer Phase formation in the La{sub 2}Mo{sub 2}O{sub 9}-Nd{sub 2}W{sub 2}O{sub 9}-'Nd{sub 2}Mo{sub 2}O{sub 9}' system has been studied. Black-Right-Pointing-Pointer Compounds isostructural with La{sub 2}Mo{sub 2}O{sub 9} were found in wide single-phase regions. Black-Right-Pointing-Pointer Tungsten stabilizes Nd{sub 2}Mo

  13. The photocatalysis of Bi{sub 2}MoO{sub 6} under the irradiation of blue LED

    SciTech Connect

    Sun, Yuanyuan; Wang, Wenzhong Zhang, Ling; Sun, Songmei

    2013-10-15

    Graphical abstract: - Highlights: • ·OH trap and hole sink were involved to investigate the active radicals. • Holes play a more important role in the degradation of RhB. • The ·OH were related to the decomposition of phenol. • The ·O{sub 2}-played a leading role in the photodegradation of phenol. • Blue LED is competitive and promising alternative for the future application. - Abstract: Bi{sub 2}MoO{sub 6} has been reported as a promising photocatalyst in wastewater treatment. The active radicals generated over the Bi{sub 2}MoO{sub 6} during the photocatalytic process were thought to be hydroxyl radical (·OH) but have not been proved. Herein, Bi{sub 2}MoO{sub 6} with nanoplate like morphology was synthesized and its photocatalytic performances in the degradation of rhodamine B (RhB) and phenol as colored and colorless model pollutants respectively were evaluated under the irradiation of blue light emitting diode (LED). The tert-butyl alcohol (TBA) as a ·OH trap and ethylene diamine tetraacetic acid (EDTA) as a hole sink were involved to investigate the main active groups that are generated on Bi{sub 2}MoO{sub 6} and function during the photodegradation of RhB and phenol. In addition, it is a competitive and promising alternative plan to use blue LED as light source for the future practical application in environmental remediation.

  14. Single-crystal structure of vanadium-doped La{sub 2}Mo{sub 2}O{sub 9}

    SciTech Connect

    Alekseeva, O. A. Antipin, A. M.; Gagor, A.; Pietraszko, A.; Novikova, N. E.; Sorokina, N. I.; Kharitonova, E. P.; Voronkova, V. I.

    2013-11-15

    A high-precision X-ray diffraction study of single crystals of two compositions-La{sub 2}Mo{sub 1.78}V{sub 0.22}O{sub 8.89} and La{sub 2}Mo{sub 1.64}V{sub 0.36}O{sub 8.82}-was performed. In the vanadium-doped compounds, as in the structure of the metastable {beta}{sub ms} phase of pure La{sub 2}Mo{sub 2}O{sub 9}, the La and Mo atoms and one of the three oxygen atoms are displaced from the threefold axis, on which they are located in the high-temperature {beta} phase. The structure contains two partially occupied oxygen sites. It was shown that molybdenum atoms are partially replaced by vanadium atoms, which are not involved in the disordering, are located on the threefold axis, and are shifted toward one of the oxygen atoms. This is consistent with the temperature-induced changes in the structure of La{sub 2}Mo{sub 2}O{sub 9} and the changes in the properties of these crystals caused by the introduction of vanadium atoms into the structure.

  15. Synthesis, crystal structure and high-temperature transport properties of the new cluster compound Rb2Mo15Se19

    NASA Astrophysics Data System (ADS)

    Daigre, Gilles; Gougeon, Patrick; Gall, Philippe; Gautier, Régis; Guillou, Olivier; Vaney, Jean-Baptiste; Candolfi, Christophe; Dauscher, Anne; Lenoir, Bertrand

    2016-05-01

    We report on the synthesis, crystal structure and high-temperature transport properties of Rb2Mo15Se19, a new member of the large family of M2Mo15Se19 (M=In, Tl, K, Ba) cluster compounds. Polycrystalline samples and single crystals of the ternary selenide Rb2Mo15Se19 were obtained by solid-state reactions. The trigonal crystal structure, successfully refined in space group R 3 bar c (No. 167) with unit-cell parameters a=9.7618(1) Å, c=58.254(1) Å and Z=6, was determined by single-crystal X-ray diffraction. The crystal structure contains Mo6 Se8i Se 6 a and Mo9Se11iSe6a cluster units in equal proportion and separated from each other by large voids, which are filled up by Rb atoms. Measurements of the electrical resistivity, thermopower and thermal conductivity revealed that Rb2Mo15Se19 behaves as a p-type metal with relatively low electrical resistivity and thermopower. Despite its complex crystal structure, the lattice thermal conductivity that amounts to 1.3 W m-1 K-1 at 300 K is significantly higher than in Ag-filled analogues, which provides possible guidelines to enhance its thermoelectric properties.

  16. Material characterization of superplastically formed titanium (Ti-6Al-2Sn-4Zr-2Mo) sheet

    NASA Technical Reports Server (NTRS)

    Ossa, William A.; Royster, Dick M.

    1987-01-01

    The aerospace industry has focused considerable interest on the near-alpha titanium alloy Ti-6Al-2Sn-4Zr-2Mo (Ti-6242) because of both its high-temperature properties and its superplastic forming (SPF) capabilities. This paper describes current research to characterize selected mechanical properties of Ti-6242 sheet in the SPF-strained condition, both with and without heat treatment, and compares the results with those obtained on as-received material. Tensile and creep tests were conducted, and metallographic analysis was performed to show the effect of 100 to 700 percent SPF strain on titanium properties. Analysis shows that as a result of SPF processing, both tensile and yield strengths, as well as elongation, are moderately reduced. Creep tests at 800 F and 1000 F show that the SPF processed material displays superior creep resistance compared with the as-received material. A post-SPF duplex-anneal heat treatment had no beneficial effect on tensile and creep properties.

  17. Austenite Formation from Martensite in a 13Cr6Ni2Mo Supermartensitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Bojack, A.; Zhao, L.; Morris, P. F.; Sietsma, J.

    2016-05-01

    The influence of austenitization treatment of a 13Cr6Ni2Mo supermartensitic stainless steel (X2CrNiMoV13-5-2) on austenite formation during reheating and on the fraction of austenite retained after tempering treatment is measured and analyzed. The results show the formation of austenite in two stages. This is probably due to inhomogeneous distribution of the austenite-stabilizing elements Ni and Mn, resulting from their slow diffusion from martensite into austenite and carbide and nitride dissolution during the second, higher temperature, stage. A better homogenization of the material causes an increase in the transformation temperatures for the martensite-to-austenite transformation and a lower retained austenite fraction with less variability after tempering. Furthermore, the martensite-to-austenite transformation was found to be incomplete at the target temperature of 1223 K (950 °C), which is influenced by the previous austenitization treatment and the heating rate. The activation energy for martensite-to-austenite transformation was determined by a modified Kissinger equation to be approximately 400 and 500 kJ/mol for the first and the second stages of transformation, respectively. Both values are much higher than the activation energy found during isothermal treatment in a previous study and are believed to be effective activation energies comprising the activation energies of both mechanisms involved, i.e., nucleation and growth.

  18. Vertical and in-plane heterostructures from WS2/MoS2 monolayers.

    PubMed

    Gong, Yongji; Lin, Junhao; Wang, Xingli; Shi, Gang; Lei, Sidong; Lin, Zhong; Zou, Xiaolong; Ye, Gonglan; Vajtai, Robert; Yakobson, Boris I; Terrones, Humberto; Terrones, Mauricio; Tay, Beng Kang; Lou, Jun; Pantelides, Sokrates T; Liu, Zheng; Zhou, Wu; Ajayan, Pulickel M

    2014-12-01

    Layer-by-layer stacking or lateral interfacing of atomic monolayers has opened up unprecedented opportunities to engineer two-dimensional heteromaterials. Fabrication of such artificial heterostructures with atomically clean and sharp interfaces, however, is challenging. Here, we report a one-step growth strategy for the creation of high-quality vertically stacked as well as in-plane interconnected heterostructures of WS2/MoS2 via control of the growth temperature. Vertically stacked bilayers with WS2 epitaxially grown on top of the MoS2 monolayer are formed with preferred stacking order at high temperature. A strong interlayer excitonic transition is observed due to the type II band alignment and to the clean interface of these bilayers. Vapour growth at low temperature, on the other hand, leads to lateral epitaxy of WS2 on MoS2 edges, creating seamless and atomically sharp in-plane heterostructures that generate strong localized photoluminescence enhancement and intrinsic p-n junctions. The fabrication of heterostructures from monolayers, using simple and scalable growth, paves the way for the creation of unprecedented two-dimensional materials with exciting properties. PMID:25262094

  19. Unveiling hidden ferrimagnetism and giant magnetoelectricity in polar magnet Fe2Mo3O8

    PubMed Central

    Wang, Yazhong; Pascut, Gheorghe L.; Gao, Bin; Tyson, Trevor A.; Haule, Kristjan; Kiryukhin, Valery; Cheong, Sang-Wook

    2015-01-01

    Magnetoelectric (ME) effect is recognized for its utility for low-power electronic devices. Largest ME coefficients are often associated with phase transitions in which ferroelectricity is induced by magnetic order. Unfortunately, in these systems, large ME response is revealed only upon elaborate poling procedures. These procedures may become unnecessary in single-polar-domain crystals of polar magnets. Here we report giant ME effects in a polar magnet Fe2Mo3O8 at temperatures as high as 60 K. Polarization jumps of 0.3 μC/cm2, and repeated mutual control of ferroelectric and magnetic moments with differential ME coefficients on the order of 104 ps/m are achieved. Importantly, no electric or magnetic poling is needed, as necessary for applications. The sign of the ME coefficients can be switched by changing the applied “bias” magnetic field. The observed effects are associated with a hidden ferrimagnetic order unveiled by application of a magnetic field. PMID:26194108

  20. Substellar objects around the sdB eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Zhu, Liying; Qian, Shengbang; Liao, Wenping; Zhao, Ergang; Li, Linjia

    2016-07-01

    The sdB-type eclipsing binary consists a very hot subdwarf B (sdB) type primary and a low mass secondary with short period. They are detached binaries and show very narrow eclipse profiles, which benefits the determination of the precise eclipse times. With the precise times of light minimum, we can detected small mass objects around them by analyzing the observed-calculated (O-C) curve based on the light time effect. For searching the substellar objects orbiting around the binaries, we have monitored sdB-type eclipsing binaries for decades. A group of brown dwarfs and planets have been detected since then. In the present paper, we focus on the target NSVS07826147, which may be another exoplanet host candidate among the group of the sdB-type eclipsing binaries.

  1. Photometric Survey to Search for Field sdO Pulsators

    NASA Astrophysics Data System (ADS)

    Johnson, C.; Green, E.; Wallace, S.; O'Malley, C.; Amaya, H.; Biddle, L.; Fontaine, G.

    2014-04-01

    We present the results of a campaign to search for subdwarf O (sdO) star pulsators among bright field stars. The motivation for this project is the recent discovery by Randall et al. (2011) of four rapidly pulsating sdO stars in the globular cluster ω Cen, with Teff near 50,000 K, 5.4 < log g < 6.0, and hydrogen-rich atmospheres. The only previously known sdO pulsator is significantly hotter at 68,500 K and log g = 6.1. All of the sdO pulsators identified so far are fainter than V≍17.4 and, thus, are poor candidates for an in-depth follow-up with asteroseismology. We therefore obtained high S/N light curves and spectroscopy for a number of field sdO stars to attempt to discover bright counterparts to these stars, particularly the ω Cen pulsators. Our primary sample consisted of 19 sdO stars with hydrogen-rich atmospheres, log N(He)/N(H) < -1.0, effective temperatures in the range 40,000 K < Teff < 67,000 K, and surface gravities 5.3 < log g < 6.1. We also observed 17 additional helium-rich sdO stars with log N(He)/N(H) > -0.1 and similar temperatures and gravities. To date, we have found no detectable pulsations at amplitudes above 0.08% (4 times the mean noise level) in any of the 36 field sdO stars that we observed. The presence of pulsations in ω Cen sdO stars and their apparent absence in seemingly comparable field sdO stars is perplexing. While very suggestive, the significance of this result is difficult to assess more completely right now due to remaining uncertainties about the temperature width and purity of the ω Cen instability strip and the existence of any sdO pulsators with weaker amplitudes than the current detection limit in globular clusters.

  2. Composite particle representation for light sd shell nuclei

    SciTech Connect

    Collinson, D.F.

    1986-01-01

    The Composite Particle Representation is applied to light sd shell nuclei /sup 20/O, /sup 20/F and /sup 20/Ne. The energy spectrum is found to agree exactly with the shell model in all cases. The CPR theory is then used to examine the possible boson structure of sd shell wavefunctions. Only in the case of /sup 20/O are the wavefunctions found to have a high boson probability.

  3. An efficient photocatalyst for degradation of various organic dyes: Ag@Ag2MoO4-AgBr composite.

    PubMed

    Bai, Yu-Yang; Lu, Yi; Liu, Jin-Ku

    2016-04-15

    The Ag2MoO4-AgBr composite was prepared by a facile in-situ anion-exchange method, then the Ag nanoparticles were coated on this composite through photodeposition route to form a novel Ag@Ag2MoO4-AgBr composite. The in-situ Br(-) replacement in a crystal lattice node position of Ag2MoO4 crystal allows for overcoming the resistance of electron transition effectively. Meanwhile silver nano-particles on the surface of Ag@Ag2MoO4-AgBr composite could act as electron traps to intensify the photogeneration electron-hole separation and the subsequent transfer of the trapped electron to the adsorbed O2 as an electron acceptor. As an efficient visible light catalyst, the Ag@Ag2MoO4-AgBr composite exhibited superior photocatalytic activity for the degradation of various organic dyes. The experimental results demonstrated superior photocatalytic rate of Ag@Ag2MoO4-AgBr composite compared to pure AgBr and Ag2MoO4 crystals (37.6% and 348.4% enhancement respectively). The Ag@Ag2MoO4-AgBr composite cloud degraded Rhodamin B, bromophenol blue, and amino black 10b completed in 7min. PMID:26775100

  4. Heat capacity, entropy of Ln2(MoO4)3 (Ln = La, Sm, and Gd), and the high-temperature enthalpy of Ln2(MoO4)3 (Ln = Eu, Dy, and Ho)

    NASA Astrophysics Data System (ADS)

    Lazarev, V. M.; Suponitskiy, Y. L.; Liashenko, S. E.

    2016-05-01

    The low-temperature heat capacity of Ln2(MoO4)3 (Ln = La, Sm, and Gd) is investigated by means of adiabatic calorimetry within the range of 60-300 K. The temperature dependences of the heat capacity are found and the values of the standard entropy are calculated, based on extrapolations to 0 K. Characteristic temperatures for molybdates are determined from the results of IR spectroscopic studies. The high-temperature enthalpy of Ln2(MoO4)3 (Ln = Eu, Dy, and Ho) is measured via high-temperature microcalorimetry, and the temperature dependence of heat capacity is calculated in the range of 298-1000 K. Since samarium and gadolinium molybdates are of the same structural type as terbium molybdate, we can estimate the anomaly of the heat capacity in the low-temperature region using the data for terbium molybdate and find the entropy of samarium and gadolinium molybdates.

  5. Effects of Na2MoO4 and Na2WO4 on molybdenum and tungsten electrodes for the alkali metal thermoelectric converter (AMTEC)

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Wheeler, B. L.; Jeffries-Nakamura, B.; Loveland, M. E.; Bankston, C. P.

    1988-01-01

    The effects of adding Na2MoO4 and Na2WO4 to porous Mo and W electrodes, respectively, on the performance and impedance characteristics of the electrodes in an alkali metal thermoelectric converter (AMTEC) were investigated. It was found that corrosion of the porous electrode by Na2MoO4 or Na2WO4 to form Na2MO3O6 and WO2, respectively, and recrystallization of the Mo or W as the salt evaporates, result in major morphological changes including a loss of columnar structure and a significant increase in porosity. This effect is more pronounced in Na2MoO4/Mo electrodes, due to the lower stability of Na2MoO4.

  6. SiO{sub 2}/Bi{sub 2}MoO{sub 6} nanocomposites with high photocatalytic activity under visible light irradiation

    SciTech Connect

    Lin, Xue; Guo, Xiaoyu; Liu, Di; Wang, Qingwei; Zhai, Hongju; Chang, Limin

    2015-03-15

    Highlights: • The SiO{sub 2}/Bi{sub 2}MoO{sub 6} composite photocatalysts were synthesized. • SiO{sub 2}/Bi{sub 2}MoO{sub 6} showed better photocatalytic performance than pure SiO{sub 2} and Bi{sub 2}MoO{sub 6}. • The photocatalytic mechanism of SiO{sub 2}/Bi{sub 2}MoO{sub 6} composite was also proposed. - Abstract: The effect of SiO{sub 2} nanoparticles on Bi{sub 2}MoO{sub 6} photocatalytic performance was described. The results indicated that SiO{sub 2} nanospheres were dispersed on Bi{sub 2}MoO{sub 6} nanosheets to form heterostructures with higher specific surface area and more intensive absorption within the visible light range in comparison with pure Bi{sub 2}MoO{sub 6}. These excellent structural and spectral properties endowed the SiO{sub 2}–Bi{sub 2}MoO{sub 6} composites with enhanced photocatalytic activities. The photocatalytic results for the degradation of Rhodamine B (Rh B) indicated that the most active composite proportion is 13.4%SiO{sub 2}–Bi{sub 2}MoO{sub 6}. The high visible light photocatalytic performance was attributed to the synergistic effect between SiO{sub 2} and Bi{sub 2}MoO{sub 6}, intensive absorption within the visible light range, and high specific surface area. It was also found that the photodegradation of Rh B molecules is mainly attributed to the oxidation action of the generated O{sub 2}·{sup −} radicals and partly to the action of h{sub vb}{sup +} through direct hole oxidation process.

  7. Purification, Characterization, and Optimum Conditions of Fermencin SD11, a Bacteriocin Produced by Human Orally Lactobacillus fermentum SD11.

    PubMed

    Wannun, Phirawat; Piwat, Supatcharin; Teanpaisan, Rawee

    2016-06-01

    Fermencin SD11, a bacteriocin produced by human orally Lactobacillus fermentum SD11, was purified, characterized, and optimized in conditions for bacterial growth and bacteriocin production. Fermencin SD11 was purified using three steps of ammonium sulfate precipitation, gel filtration chromatography, and reverse-phase high-performance liquid chromatography. The molecular weight was found to be 33,000 Da using SDS-PAGE and confirmed as 33,593.4 Da by liquid chromatography-mass spectrometry. Fermencin SD11 exhibited activity against a wide range of oral pathogens including cariogenic and periodontogenic pathogens and Candida. The active activity was stable between 60 - 80 °C in a pH range of 3.0 to 7.0. It was sensitive to proteolytic enzymes (proteinase K and trypsin), but it was not affected by α-amylase, catalase, lysozyme, and saliva. The optimum conditions for growth and bacteriocin production of L. fermentum SD11 were cultured at acidic with pH of 5.0-6.0 at 37 or 40 °C under aerobic or anaerobic conditions for 12 h. It is promising that L. fermentum SD11 and its bacteriocin may be an alternative approach for promoting oral health or prevention of oral diseases, e.g., dental caries and periodontitis, which would require further clinical trials. PMID:26892008

  8. "White" phosphor on the basis of Gd2(MoO4)3: Tm,Tb,Eu single crystal

    NASA Astrophysics Data System (ADS)

    Sinitsyn, V. V.; Redkin, B. S.; Kiselev, A. P.; Shmurak, S. Z.; Kolesnikov, N. N.; Kveder, V. V.; Ponyatovsky, E. G.

    2015-08-01

    A single-crystal sample of Gd2(MoO4)3 simultaneously doped with europium, terbium and thulium is grown. The Tm, Tb and Eu dopants are employed as the luminescent centers emitting light in the red, green and blue ranges. Spectroscopy investigation reveals that simultaneous luminescence of the centers of all three types to produce white light occurs only under the sample excitation with ultraviolet (UV) light within the wavelength range 350 < λ < 370 nm. A commercial UV light-emitting diode (LED) with λLED = 365 nm is applied in order to show that the Gd2(MoO4)3:Tm,Tb,Eu crystal converts its UV flux into white light. So, it is demonstrated that white light may be produced using one matrix with luminous centers of three types.

  9. Tunable properties of spin waves in magnetoelastic {NiFe}/{{Gd}}_{2}{({{MoO}}_{4})}_{3} heterostructure

    NASA Astrophysics Data System (ADS)

    Graczyk, Piotr; Trzaskowska, Aleksandra; Załȩski, Karol; Mróz, Bogusław

    2016-07-01

    Full ferroelastic and simultaneously ferroelectric materials are interesting candidates for applications in devices based on multiferroic heterostructures. They should allow for non-volatile and low-power writing of data bits in magnetoelectric random access memories. Moreover, ferroelasticity, in contrast to piezoelectric material, make magnetic information in ferromagnetic film resistant to external fields. As an example for such a system, we have studied the magnetoelastic interaction between a thin ferromagnetic layer of {{Ni}}85{{Fe}}15 with a full ferroelastic–ferroelectric gadolinium molybdate {{Gd}}2{({{MoO}}4)}3 crystal. We have investigated the influence of {{Gd}}2{({{MoO}}4)}3 spontaneous strain onto magnetic properties of thin ferromagnetic film. Particularly, we have shown by Brillouin spectroscopy, that it is possible to modulate surface spin wave frequency of {{Ni}}85{{Fe}}15 by spontaneous strain of gadolinium molybdate substrate.

  10. Cube-like Cu2MoS4 photocatalysts for visible light-driven degradation of methyl orange

    NASA Astrophysics Data System (ADS)

    Zhang, Ke; Chen, Wenxing; Wang, Yu; Li, Jiong; Chen, Haiping; Gong, Zhiyu; Chang, Shuo; Ye, Fei; Wang, Tianxing; Chu, Wangsheng; Zou, Chongwen; Song, Li

    2015-07-01

    Cube-like Cu2MoS4 nanoparticles with low-index facets and high crystallinity were fabricated via a hydrothermal method. The as-obtained nanocubes with an average size of 40-60 nm are composed of stacking-Cu2MoS4 layers separated by a weak Van der Waals gap of 0.5 nm. A strong absorption at visible light region is observed in the nanocube aqueous solution, indicating its optical-band gap of 1.78 eV. The photocatalytic measurements reveal that the nanocubes can thoroughly induce the degradation of methyl orange under visible light irradiation with good structural stability. Our finding may provide a way in design and fabrication of transition metal dichalcogenide nanostructures for practical applications.

  11. Phonon mode spectroscopy, electron-phonon coupling, and the metal-insulator transition in quasi-one-dimensional M2Mo6Se6

    NASA Astrophysics Data System (ADS)

    Petrović, A. P.; Lortz, R.; Santi, G.; Decroux, M.; Monnard, H.; Fischer, Ø.; Boeri, L.; Andersen, O. K.; Kortus, J.; Salloum, D.; Gougeon, P.; Potel, M.

    2010-12-01

    We present electronic-structure calculations, electrical resistivity data, and the first specific-heat measurements in the normal and superconducting states of quasi-one-dimensional M2Mo6Se6 (M=Tl,In,Rb) . Rb2Mo6Se6 undergoes a metal-insulator transition at ˜170K : electronic-structure calculations indicate that this is likely to be driven by the formation of a dynamical charge-density wave. However, Tl2Mo6Se6 and In2Mo6Se6 remain metallic down to low temperature, with superconducting transitions at Tc=4.2K and 2.85 K, respectively. The absence of any metal-insulator transition in these materials is due to a larger in-plane bandwidth, leading to increased interchain hopping which suppresses the density wave instability. Electronic heat-capacity data for the superconducting compounds reveal an exceptionally low density of states DEF=0.055 states eV-1atom-1 , with BCS fits showing 2Δ/kBTc≥5 for Tl2Mo6Se6 and 3.5 for In2Mo6Se6 . Modeling the lattice specific heat with a set of Einstein modes, we obtain the approximate phonon density of states F(ω) . Deconvolving the resistivity for the two superconductors then yields their electron-phonon transport coupling function αtr2F(ω) . In Tl2Mo6Se6 and In2Mo6Se6 , F(ω) is dominated by an optical “guest ion” mode at ˜5meV and a set of acoustic modes from ˜10 to 30 meV. Rb2Mo6Se6 exhibits a similar spectrum; however, the optical phonon has a lower intensity and is shifted to ˜8meV . Electrons in Tl2Mo6Se6 couple strongly to both sets of modes, whereas In2Mo6Se6 only displays significant coupling in the 10-18 meV range. Although pairing is clearly not mediated by the guest ion phonon, we believe it has a beneficial effect on superconductivity in Tl2Mo6Se6 , given its extraordinarily large coupling strength and higher Tc compared to In2Mo6Se6 .

  12. Microwave Spectrum of the SD+3 Ion: Molecular Structure.

    PubMed

    Araki; Ozeki; Saito

    1998-11-01

    The J = 1-0 to 4-3 spectral lines of SD+3 were measured in the 152-610 GHz region using a source-modulated microwave spectrometer. The SD+3 ion was generated in a free space absorption cell by a hollow-cathode discharge in a gas mixture of D2S and D2. The rotational constant B0 and the centrifugal distortion constants DJ and DJK were determined from the measured frequencies. A vibration-rotation analysis was carried out and the rz structures of SH+3 and SD+3 were derived from their zero point averaged rotational constants, expressed as SH+3: rz = 1.36512(22) Å and thetaz = 94.098(26) degrees, and SD+3: rz = 1.36086(16) Å and thetaz = 94.1211(195) degrees, where the difference between thetaz(HSH) and thetaz(DSD) was assumed to be the same as that between thetaz(HPH) of PH3 and thetaz(DPD) of PD3. From the shift between the rz structures of SH+3 and SD+3, the re structure of SH+3 was estimated to be re = 1.35001(113) Å, thetae = 94.181(135) degrees. Copyright 1998 Academic Press. PMID:9770407

  13. Decay out of SD Band in ^192Pb

    NASA Astrophysics Data System (ADS)

    McNabb, D. P.; Cizewski, J. A.; Ding, K. Y.; Fotiades, N.; Archer, D. E.; Becker, J. A.; Bernstein, L. A.; Hauschild, K.; Younes, W.; Clark, R. M.; Fallon, P.; Lee, I. Y.; Macchiavelli, A. O.; MacLeod, R. W.

    1997-04-01

    Gamma-ray transitions linking the yrast SD bands to the known (ND) levels have been found in ^194Pb(M. J. Brinkman, et al., Phys. Rev. C53), R1461 (1996), A. Lopez-Martens, et al., Phys. Lett. B380, 18 (1996) and K. Hauschild, et al., submitted to Phys. Rev. C (1996). and ^194Hg.(T. L. Khoo, et al., Phys. Rev. Lett. 76), 1583 (1996). The spin, parity and excitation energy of these SD bands were established. Linking transitions are understood as arising from ND states nearby in excitation energy which are admixed with the SD states.(E. Vigezzi, et al., Phys. Lett. B249), 163 (1990). We anticipate a smaller phase space for quasicontinuous decay of the SD band in ^192Pb because it is predicted to lie lower in excitation than the SD band in ^194Pb.footnote S. J. Krieger, et al. Nucl. Phys. A542, 43 (1992). To search for linking transitions in ^192Pb we used the Gammasphere array at LBNL and the ^24Mg(^173Yb,5n) reaction at 134 MeV. Candidates for linking transitions and general features of the decay will be discussed.

  14. SD-CAS: Spin Dynamics by Computer Algebra System.

    PubMed

    Filip, Xenia; Filip, Claudiu

    2010-11-01

    A computer algebra tool for describing the Liouville-space quantum evolution of nuclear 1/2-spins is introduced and implemented within a computational framework named Spin Dynamics by Computer Algebra System (SD-CAS). A distinctive feature compared with numerical and previous computer algebra approaches to solving spin dynamics problems results from the fact that no matrix representation for spin operators is used in SD-CAS, which determines a full symbolic character to the performed computations. Spin correlations are stored in SD-CAS as four-entry nested lists of which size increases linearly with the number of spins into the system and are easily mapped into analytical expressions in terms of spin operator products. For the so defined SD-CAS spin correlations a set of specialized functions and procedures is introduced that are essential for implementing basic spin algebra operations, such as the spin operator products, commutators, and scalar products. They provide results in an abstract algebraic form: specific procedures to quantitatively evaluate such symbolic expressions with respect to the involved spin interaction parameters and experimental conditions are also discussed. Although the main focus in the present work is on laying the foundation for spin dynamics symbolic computation in NMR based on a non-matrix formalism, practical aspects are also considered throughout the theoretical development process. In particular, specific SD-CAS routines have been implemented using the YACAS computer algebra package (http://yacas.sourceforge.net), and their functionality was demonstrated on a few illustrative examples. PMID:20843716

  15. High-temperature behavior of dicesium molybdate Cs2MoO4: Implications for fast neutron reactors

    NASA Astrophysics Data System (ADS)

    Wallez, Gilles; Raison, Philippe E.; Smith, Anna L.; Clavier, Nicolas; Dacheux, Nicolas

    2014-07-01

    Dicesium molybdate (Cs2MoO4)'s thermal expansion and crystal structure have been investigated herein by high temperature X ray diffraction in conjunction with Raman spectroscopy. This first crystal-chemical insight at high temperature is aimed at predicting the thermostructural and thermomechanical behavior of this oxide formed by the accumulation of Cs and Mo fission products at the periphery of nuclear fuel rods in sodium-cooled fast reactors. Within the temperature range of the fuel's rim, Cs2MoO4 becomes hexagonal P63/mmc, with disordered MoO4 tetrahedra and 2D distribution of Cs-O bonds that makes thermal axial expansion both large (50≤αl≤70 10-6 °C-1, 500-800 °C) and highly anisotropic (αc-αa=67×10-6 °C-1, hexagonal form). The difference with the fuel's expansion coefficient is of potential concern with respect to the cohesion of the Cs2MoO4 surface film and the possible release of cesium radionuclides in accidental situations.

  16. 78 FR 39820 - Standing Rock Sioux Tribe Disaster #SD-00058

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-02

    ... ADMINISTRATION Standing Rock Sioux Tribe Disaster SD-00058 AGENCY: U.S. Small Business Administration. ACTION... Assistance Only for the Standing Rock Indian Reservation (FEMA-4123-DR), dated 06/25/2013. Incident: Severe... adversely affected by the disaster: Primary Area: Standing Rock Indian Reservation. The Interest Rates...

  17. 75 FR 4417 - Wind Cave National Park, Custer County, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... Wind Cave National Park, Custer County, SD AGENCY: National Park Service. ACTION: Notice of... Statement, Wind Cave National Park, Custer County, South Dakota. SUMMARY: Pursuant to Section 102(2)(C) of... Environmental Impact Statement (Plan), Wind Cave National Park, Custer County, South Dakota. On December 3,...

  18. 76 FR 35935 - South Dakota Disaster Number SD-00041

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ... From the Federal Register Online via the Government Publishing Office U.S. SMALL BUSINESS ADMINISTRATION South Dakota Disaster Number SD-00041 AGENCY: U.S. Small Business Administration. ACTION... completed loan applications to: U.S. Small Business Administration, Processing and Disbursement...

  19. 76 FR 35936 - South Dakota Disaster Number SD-00041

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ... From the Federal Register Online via the Government Publishing Office U.S. SMALL BUSINESS ADMINISTRATION South Dakota Disaster Number SD-00041 AGENCY: U.S. Small Business Administration. ACTION... completed loan applications to: U.S. Small Business Administration, Processing and Disbursement...

  20. 78 FR 29425 - South Dakota Disaster #SD-00057

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-20

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  1. 76 FR 40767 - South Dakota Disaster Number SD-00041

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    2011-07-11

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  2. 75 FR 19435 - South Dakota Disaster Number SD-00027

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-14

    ... ADMINISTRATION South Dakota Disaster Number SD-00027 AGENCY: Small Business Administration. ACTION: Amendment 1... Only for the State of South Dakota (FEMA-1886-DR), dated 03/09/2010. Incident: Severe Winter Storm and... State of South Dakota, dated 03/09/2010, is hereby amended to include the following areas as...

  3. 75 FR 13145 - SOUTH DAKOTA Disaster #SD-00027

    Federal Register 2010, 2011, 2012, 2013, 2014

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  4. 76 FR 54520 - South Dakota Disaster #SD-00042

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-01

    ... ADMINISTRATION South Dakota Disaster SD-00042 AGENCY: U.S. Small Business Administration. ACTION: Notice. ] SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of South... Injury Loans Only): South Dakota: Aurora, Bon Homme, Brule, Clay, Dewey, Douglas, Gregory,...

  5. 75 FR 39994 - South Dakota Disaster Number SD-00031

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    2010-07-13

    ... ADMINISTRATION South Dakota Disaster Number SD-00031 AGENCY: U.S. Small Business Administration. ACTION... Assistance Only for the State of South Dakota (FEMA-1915-DR), dated 05/13/2010. Incident: Flooding. Incident... Non-Profit organizations in the State of South Dakota, dated 05/13/2010, is hereby amended to...

  6. 75 FR 28311 - South Dakota Disaster # SD-00031

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-20

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  7. 75 FR 61229 - South Dakota Disaster #SD-00034

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-04

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION South Dakota Disaster SD-00034 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of South Dakota (FEMA-1938-DR), dated 09/23/2010. Incident: Severe Storms and Flooding....

  8. 76 FR 30226 - South Dakota Disaster # SD-00041

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-24

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION South Dakota Disaster SD-00041 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of South Dakota (FEMA-1984-DR), dated 05/13/2011. Incident: Flooding. Incident Period:...

  9. 75 FR 30873 - South Dakota Disaster Number SD-00031

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    2010-06-02

    ... ADMINISTRATION South Dakota Disaster Number SD-00031 AGENCY: U.S. Small Business Administration. ACTION... Assistance Only for the State of South Dakota (FEMA-1915-DR), dated 05/13/2010. Incident: Flooding. Incident... Non-Profit organizations in the State of South Dakota, dated 05/13/2010, is hereby amended to...

  10. 75 FR 38154 - South Dakota Disaster Number SD-00031

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    2010-07-01

    ... ADMINISTRATION South Dakota Disaster Number SD-00031 AGENCY: U.S. Small Business Administration. ACTION... Assistance Only for the State of SOUTH DAKOTA (FEMA-1915-DR), dated 05/13/2010. Incident: Flooding. Incident... Non-Profit organizations in the State of SOUTH DAKOTA, dated 05/13/2010, is hereby amended...

  11. 75 FR 28312 - South Dakota Disaster # SD-00030

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-20

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION South Dakota Disaster SD-00030 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of South Dakota (FEMA-1914-DR), dated 05/13/2010. Incident: Severe Winter Storm. Incident...

  12. 75 FR 47035 - South Dakota Disaster #SD-00033

    Federal Register 2010, 2011, 2012, 2013, 2014

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  13. 75 FR 69732 - South Dakota Disaster #SD-00035

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION South Dakota Disaster SD-00035 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of South Dakota (FEMA-1947-DR), dated 11/02/2010. Incident: Severe Storms and Flooding....

  14. 77 FR 46284 - Amendment of Class E Airspace; Lemmon, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-03

    ...: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E. O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389... Federal Aviation Administration 14 CFR Part 71 Amendment of Class E Airspace; Lemmon, SD AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action amends Class E airspace...

  15. 76 FR 40597 - Amendment of Class E Airspace; Madison, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-11

    ...), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The... Federal Aviation Administration 14 CFR Part 71 Amendment of Class E Airspace; Madison, SD AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action amends Class E airspace...

  16. 78 FR 41837 - Establishment of Class E Airspace; Parkston, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-12

    ..., 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation... Federal Aviation Administration 14 CFR Part 71 Establishment of Class E Airspace; Parkston, SD AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action establishes Class...

  17. 78 FR 48764 - South Dakota Disaster # SD-00061

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-09

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION South Dakota Disaster SD-00061 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY...: Submit completed loan applications to: U.S. Small Business Administration, Processing and...

  18. Electronic and magnetic properties of Sr2MoBO6 (B=W, RE, Os): Investigation of possible half metal

    NASA Astrophysics Data System (ADS)

    Zu, Ningning; Li, Rui; Li, Qinan; Wang, Jing

    2016-02-01

    The magnetic ordering temperatures of Sr2CrBO6 (B=W, Re, Os) are the top three in the class of double perovskites so far, whereas among them only Sr2CrWO6 is a half metal. In this study, by substituting Cr with Mo, Sr2MoBO6 is investigated by using the density functional theory. The calculated results indicate that all the three Mo-based compounds exhibit the half metallic nature, in particular Sr2MoOsO6 is a compensated half metal. On the other hand, Sr2MoBO6 is estimated to have at least a comparable magnetic ordering temperature with that of Sr2CrOsO6 (experimental value of 725 K). Therefore, we expect that Sr2MoBO6 (B=W, Re, Os) would be promising candidates as spintronic materials.

  19. Excitation intensity dependence of photoluminescence from monolayers of MoS2 and WS2/MoS2 heterostructures

    NASA Astrophysics Data System (ADS)

    Kaplan, D.; Gong, Y.; Mills, K.; Swaminathan, V.; Ajayan, P. M.; Shirodkar, S.; Kaxiras, E.

    2016-03-01

    A detailed study of the excitation dependence of the photoluminescence (PL) from monolayers of MoS2 and WS2/MoS2 heterostructures grown by chemical vapor deposition on Si substrates has revealed that the luminescence from band edge excitons from MoS2 monolayers shows a linear dependence on excitation intensity for both above band gap and resonant excitation conditions. In particular, a band separated by ∼55 meV from the A exciton, referred to as the C band, shows the same linear dependence on excitation intensity as the band edge excitons. A band similar to the C band has been previously ascribed to a trion, a charged, three-particle exciton. However, in our study the C band does not show the 3/2 power dependence on excitation intensity as would be expected for a three-particle exciton. Further, the PL from the MoS2 monolayer in a bilayer WS2/MoS2 heterostructure, under resonant excitation conditions where only the MoS2 absorbs the laser energy, also revealed a linear dependence on excitation intensity for the C band, confirming that its origin is not due to a trion but instead a bound exciton, presumably of an unintentional impurity or a native point defect such as a sulfur vacancy. The PL from the WS2/MoS2 heterostructure, under resonant excitation conditions also showed additional features which are suggested to arise from the interface states at the heteroboundary. Further studies are required to clearly identify the origin of these features.

  20. In-situ determination of austenite and martensite formation in 13Cr6Ni2Mo supermartensitic stainless steel

    SciTech Connect

    Bojack, A.; Zhao, L.; Morris, P.F.; Sietsma, J.

    2012-09-15

    In-situ analysis of the phase transformations in a 13Cr6Ni2Mo supermartensitic stainless steel (X2CrNiMoV13-5-2) was carried out using a thermo-magnetic technique, dilatometry and high temperature X-ray diffractometry (HT-XRD). A combination of the results obtained by the three applied techniques gives a valuable insight in the phase transformations during the austenitization treatment, including subsequent cooling, of the 13Cr6Ni2Mo supermartensitic stainless steel, where the magnetic technique offers a high accuracy in monitoring the austenite fraction. It was found by dilatometry that the austenite formation during heating takes place in two stages, most likely caused by partitioning of Ni into austenite. The in-situ evolution of the austenite fraction is monitored by high-temperature XRD and dilatometry. The progress of martensite formation during cooling was described with a Koistinen-Marburger relation for the results obtained from the magnetic and dilatometer experiments. Enhanced martensite formation at the sample surface was detected by X-ray diffraction, which is assumed to be due to relaxation of transformation stresses at the sample surface. Due to the high alloy content and high thermodynamic stability of austenite at room temperature, 4 vol.% of austenite was found to be stable at room temperature after the austenitization treatment. - Highlights: Black-Right-Pointing-Pointer We in-situ analyzed phase transformations and fractions of a 13Cr6Ni2Mo SMSS. Black-Right-Pointing-Pointer Higher accuracy of the austenite fraction was obtained from magnetic technique. Black-Right-Pointing-Pointer Austenite formation during heating takes place in two stages. Black-Right-Pointing-Pointer Enhanced martensite formation at the sample surface detected by X-ray diffraction.

  1. The effects of Gd3+ doping on the physical structure and photocatalytic performance of Bi2MoO6 nanoplate crystals

    NASA Astrophysics Data System (ADS)

    Yu, Changlin; Wu, Zhen; Liu, Renyue; He, Hongbo; Fan, Wenhong; Xue, Shuangshuang

    2016-06-01

    Gd3+ doped Bi2MoO6 nanoplate crystals were fabricated by solvothermal combined calcination method. The effects of Gd3+ doping with different concentrations on the texture, crystal and optical properties of Bi2MoO6 were investigated by N2 physical adsorption, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR) and ultraviolet-visible diffuse reflection spectrum (UV-vis DRS), photoluminescence (PL) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Under simulated solar light irradiation, the influences of Gd3+doping on photocatalytic activity of Bi2MoO6 were evaluated by photocatalytic degradation of Rhodamine B. The characterization results showed that with Gd3+ doping, a contraction of lattice and a decrease in crystallite size occurred. Meanwhile, an increase in surface area over Gd3+ doped Bi2MoO6 was observed. Moreover, Gd3+ doping could obviously enhance the visible light harvesting of Bi2MoO6 and promoted the separation of photogenerated electrons and holes. With optimum Gd3+(6 wt%) doping, Gd/Bi2MoO6 exhibited the best activity and stability in degradation of Rhodamine B.

  2. Controlled synthesis, characterization and photoluminescence property of olive-like tetragonal α-Nd{sub 2}(MoO{sub 4}){sub 3}

    SciTech Connect

    Zhang, Youjin; Zheng, Ao; Yang, Xiaozhi; He, Hongmei; Fan, Yun

    2012-09-15

    Highlights: ► The olive-like tetragonal α-Nd{sub 2}(MoO{sub 4}){sub 3} was gained with EDTA assisted hydrothermal method. ► The product was characterized by XRD, XPS, FTIR, FESEM, and PL. ► The possible formation mechanism for olive-like α-Nd{sub 2}(MoO{sub 4}){sub 3} was proposed. ► The PL in visible region of the olive-like α-Nd{sub 2}(MoO{sub 4}){sub 3} was studied. -- Abstract: The olive-like tetragonal α-Nd{sub 2}(MoO{sub 4}){sub 3} was obtained by a convenient and facile complex agent assisted hydrothermal method. The product was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FESEM) and photoluminescence (PL). The possible formation mechanism of the olive-like α-Nd{sub 2}(MoO{sub 4}){sub 3} was proposed. The photoluminescence property in visible region of the olive-like tetragonal α-Nd{sub 2}(MoO{sub 4}){sub 3} was studied.

  3. Structural, electronic and elastic properties of the Laves phases WFe2, MoFe2, WCr2 and MoCr2 from first-principles

    NASA Astrophysics Data System (ADS)

    Lv, Z. Q.; Zhang, Z. F.; Zhang, Q.; Wang, Z. H.; Sun, S. H.; Fu, W. T.

    2016-06-01

    A theoretical analysis of the phase stability, electronic and mechanical properties, and Debye temperatures of the C14-type Laves phases (WFe2, MoFe2, WCr2 and MoCr2) has been presented from density functional theory. The phase stability follows the order: WFe2>MoFe2>WCr2>MoCr2. An exchange of electrons takes place between Fe and W/Mo atoms, and there is also electron transfer between Cr and W/Mo. The W-W and Mo-Mo bonds are of the valence character, while the Fe-W/Mo and Cr-W/Mo bonds are of ionic character. The bonding force of A-A is greater than that of A-B in C-14 AB2 type Laves phases (WFe2, MoFe2, WCr2 and MoCr2). The ductility of MoCr2 is higher than others. The hardness of WFe2 (14.1 GPa) is the highest, and the hardness of MoCr2 is the lowest. The incompressibility for these laves phases along c-axis is larger than that along a-axis. The Debye temperature (θD) of MoFe2 is 619 K, which is the highest in those phases. These laves phases also have high melting points, which follows the order: WFe2>MoFe2>WCr2>MoCr2.

  4. Structural, electronic and elastic properties of the Laves phases WFe2, MoFe2, WCr2 and MoCr2 from first-principles

    NASA Astrophysics Data System (ADS)

    Lv, Z. Q.; Zhang, Z. F.; Zhang, Q.; Wang, Z. H.; Sun, S. H.; Fu, W. T.

    2016-06-01

    A theoretical analysis of the phase stability, electronic and mechanical properties, and Debye temperatures of the C14-type Laves phases (WFe2, MoFe2, WCr2 and MoCr2) has been presented from density functional theory. The phase stability follows the order: WFe2>MoFe2>WCr2>MoCr2. An exchange of electrons takes place between Fe and W/Mo atoms, and there is also electron transfer between Cr and W/Mo. The W-W and Mo-Mo bonds are of the valence character, while the Fe-W/Mo and Cr-W/Mo bonds are of ionic character. The bonding force of A-A is greater than that of A-B in C-14 AB2 type Laves phases (WFe2, MoFe2, WCr2 and MoCr2). The ductility of MoCr2 is higher than others. The hardness of WFe2 (14.1 GPa) is the highest, and the hardness of MoCr2 is the lowest. The incompressibility for these laves phases along c-axis is larger than that along a-axis. The Debye temperature (θD) of MoFe2 is 619 K, which is the highest in those phases. These laves phases also have high melting points, which follows the order: WFe2>MoFe2>WCr2>MoCr2.

  5. Monodispersed Ag3PO4 nanocrystals loaded on the surface of spherical Bi2MoO6 with enhanced photocatalytic performance.

    PubMed

    Xu, Yang-Sen; Zhang, Wei-De

    2013-01-28

    Spherical Bi(2)MoO(6) nanoarchitectures with scale of 500 nm-2 μm were prepared by a solvothermal reaction using bismuth nitrate and ammonium molybdate as precursors. Ag(3)PO(4) nanoparticles were then deposited onto the surface of Bi(2)MoO(6)via a facile deposition-precipitation technique. The photocatalytic tests display that the Ag(3)PO(4)/Bi(2)MoO(6) nanocomposites possess a much higher rate for degradation of rhodamine B and methylene blue than the pure Ag(3)PO(4) nanoparticles and Bi(2)MoO(6) under visible light. The catalytic activity of the composite photocatalysts is greatly influenced by the loading level of Ag(3)PO(4). The 50 mol% Ag(3)PO(4)-loaded Bi(2)MoO(6) spheres exhibit the highest photocatalytic activity in both the decolorization of RhB and MB. The observed improvement in photocatalytic activity is associated with the extended absorption in the visible light region resulting from the Ag(3)PO(4) nanoparticles, and the effective separation of photogenerated carriers at the Ag(3)PO(4)/Bi(2)MoO(6) interfaces. In addition, the composite can be easily reclaimed by sedimentation without any loss of its stability. Moreover, the tests of radical scavengers confirmed that h(+) and ˙OH were the main reactive species for the degradation of RhB. PMID:23131725

  6. Theoretical studies of the spin-Hamiltonian parameters of the oxycation MoO3+ in (NH4)2MoOCl5 and K2MoOF5 single crystals

    NASA Astrophysics Data System (ADS)

    Fang, Wang; Chen, Heng-Jie; Tan, Ren-Bing; Yang, Wen-Yan; Tang, Hai-Yan

    2014-10-01

    Theoretical formulae for the spin-Hamiltonian (SH) parameters (g tensor g//, g⊥ and hyperfine structure A tensor A//, A⊥) of the ground state of oxycation MoO3+ in [MOX5]2- (M=Mo5+, Cr4+, V3+, X=F-, Cl- or Br- ) complexes are derived by the high-order perturbation method within the frame of molecular orbital (MO) scheme. In those formulae, the contributions to the SH parameters arising both from the crystal field (CF) and charge transfer (CT) excitations are taken into account, which are derived up to the third and second order, respectively. Those formulae are applied to calculate the SH of the oxycation MoO3+ in (NH4)2MoOCl5 and K2MoOF5 single crystals by the best match method, and the calculated results are in good agreement with the experimental data. The investigations show that the charge transfer mechanism play a decisive role in the understanding for the SH parameters for 4d1 ions in crystals with the strong coordinate covalence, especially for anomalously experimental results g//>g⊥ which cannot be explained by the traditional CF approximation alone. The MO coefficients are determined and the results are discussed.

  7. P2Y nucleotide receptors: Promise of therapeutic applications

    PubMed Central

    Jacobson, Kenneth A.; Boeynaems, Jean-Marie

    2010-01-01

    Extracellular nucleotides, such as ATP and UTP, have distinct signaling roles through a class of G protein-coupled receptors, termed P2Y. However, the receptor ligands are typically charged molecules of low bioavailability and stability in vivo. Recent progress in the development of selective agonists and antagonists for P2Y receptors and study of knockout mice have led to new drug concepts based on these receptors. The rapidly accelerating progress in this field has already resulted in drug candidates for cystic fibrosis, dry eye disease, and thrombosis. On the horizon are novel treatments of cardiovascular diseases, inflammatory diseases, and neurodegeneration. PMID:20594935

  8. Carbon abundances of sdO stars from SPY

    NASA Astrophysics Data System (ADS)

    Hirsch, Heiko; Heber, Uli

    2009-06-01

    Ströer et al. (2007) recently suggested a classification of sdOs according to supersolar and subsolar helium abundances, with only the helium-enriched stars showing signes of carbon and/or nitrogen in their optical spectra. We aim to derive reliable carbon and nitrogen abundances by fitting synthetic spectra to data obtained with the UVES spectrograph at ESO. Here we present our first results of the analysis of carbon abundances in hot subdwarf O stars. By constructing a grid of model atmospheres consisting of hydrogen, helium and carbon we were able to derive atmospheric parameters of nine carbon rich sdOs. We find log(NC/Ntotal) up to ten times higher than the solar value, while the mean value for the effective temperature and the surface gravity is slightly lower than derived by helium-hydrogen models only. Surprisingly, we also find three fast rotators among our program stars.

  9. Shell Model Depiction of Isospin Mixing in sd Shell

    SciTech Connect

    Lam, Yi Hua; Smirnova, Nadya A.; Caurier, Etienne

    2011-11-30

    We constructed a new empirical isospin-symmetry breaking (ISB) Hamiltonian in the sd(1s{sub 1/2}, 0d{sub 5/2} and 0d{sub 3/2}) shell-model space. In this contribution, we present its application to two important case studies: (i){beta}-delayed proton emission from {sup 22}Al and (ii) isospin-mixing correction to superallowed 0{sup +}{yields}0{sup +}{beta}-decay ft-values.

  10. Gray-shading for the SD-4060 graphics device

    NASA Technical Reports Server (NTRS)

    Gloeckler, C.

    1975-01-01

    Grays, a FORTRAN program, is described which will generate gray shading for the SD-4060 graphics device. The program produces 10 shades of gray ranging from no shading at all to complete coverage of the film frame. The graphing capabilities are summarized and illustrated. The figures displayed are representative of the microfilm output, but the distinction between various intensities is much clearer on the film, especially at the more intense shading.

  11. Sex differences in the stress response in SD rats.

    PubMed

    Lu, Jing; Wu, Xue-Yan; Zhu, Qiong-Bin; Li, Jia; Shi, Li-Gen; Wu, Juan-Li; Zhang, Qi-Jun; Huang, Man-Li; Bao, Ai-Min

    2015-05-01

    Sex differences play an important role in depression, the basis of which is an excessive stress response. We aimed at revealing the neurobiological sex differences in the same study in acute- and chronically-stressed rats. Female Sprague-Dawley (SD) rats were randomly divided into 6 groups: chronic unpredictable mild stress (CUMS), acute foot shock (FS) and controls, animals in all 3 groups were sacrificed in proestrus or diestrus. Male SD rats were randomly divided into 3 groups: CUMS, FS and controls. Comparisons were made of behavioral changes in CUMS and control rats, plasma levels of corticosterone (CORT), testosterone (T) and estradiol (E2), and of the hypothalamic mRNA-expression of stress-related molecules, i.e. estrogen receptor α and β, androgen receptor, aromatase, mineralocorticoid receptor, glucocorticoid receptor, corticotropin-releasing hormone, arginine vasopressin and oxytocin. CUMS resulted in disordered estrus cycles, more behavioral and hypothalamic stress-related molecules changes and a stronger CORT response in female rats compared with male rats. Female rats also showed decreased E2 and T levels after FS and CUMS, while male FS rats showed increased E2 and male CUMS rats showed decreased T levels. Stress affects the behavioral, endocrine and the molecular response of the stress systems in the hypothalamus of SD rats in a clear sexual dimorphic way, which has parallels in human data on stress and depression. PMID:25687843

  12. Characteristics of new P2Y12 inhibitors: selection of P2Y12 inhibitors in clinical practice.

    PubMed

    Golino, Paolo

    2013-12-01

    The options for antithrombotic therapy have recently been expanded, facilitating optimal tailored treatment. Dual antiplatelet therapy with aspirin and an approved adenosine diphosphate P2Y12 receptor antagonist is recommended for the management of patients with acute coronary syndromes (ACS). However, there are a number of controversies: which P2Y12 inhibitor to choose; how long should antiplatelet therapy be used so as to prevent thrombotic events and minimize bleeding risks; whether to use drug-eluting (DES) or bare-metal stents (BMS) and how to manage the individual variability in response to clopidogrel. Clopidogrel in combination with aspirin has been the standard dual antiplatelet regimen for ACS. The new, more potent P2Y12 inhibitors, prasugrel and ticagrelor, have shown improved antithrombotic effects compared with clopidogrel in patients with ACS (with or without ST-segment elevation myocardial infarction) in landmark trials, even if they were associated with an increased risk of major bleeding. Different pharmacogenetic and pharmacodynamic characteristics may explain, in part, the different pharmacologic and clinical responses to these antiplatelet agents. Importantly, both clopidogrel and prasugrel are prodrugs, i.e., they need to be converted in vivo into active metabolites that selectively and irreversibly bind the P2Y12 receptor. Unlike clopidogrel, however, common functional cytochrome P450 genetic variants do not affect prasugrel active metabolite levels or inhibition of platelet aggregation. In contrast, ticagrelor is not a prodrug (i.e., does not require hepatic metabolism to exert its antiplatelet effect) and represents the first oral P2Y12 receptor antagonist that is reversibly bound. Similar to prasugrel, ticagrelor achieves greater and more rapid inhibition of platelet function than clopidogrel. Evidence suggests that the new P2Y12 antagonists may offer improved antithrombotic effects compared with clopidogrel in selected patients for the

  13. Residual platelet ADP reactivity after clopidogrel treatment is dependent on activation of both the unblocked P2Y1 and the P2Y12 receptor and is correlated with protein expression of P2Y12

    PubMed Central

    Braun, Oscar Ö; Amisten, Stefan; Wihlborg, Anna-Karin; Hunting, Karen; Nilsson, David

    2006-01-01

    Two ADP receptors have been identified on human platelets: P2Y1 and P2Y12. The P2Y12 receptor blocker clopidogrel is widely used to reduce the risks in acute coronary syndromes, but, currently, there is no P2Y1 blocker in clinical use. Evidence for variable responses to clopidogrel has been described in several reports. The mechanistic explanation for this phenomenon is not fully understood. The aim of this study was to examine mechanisms responsible for variability of 2MeS-ADP, a stable ADP analogue, induced platelet reactivity in clopidogrel-treated patients. Platelet reactivity was assessed by flow cytometry measurements of P-selectin (CD62P) and activated GpIIb/IIIa complex (PAC-1). Residual 2MeS-ADP activation via the P2Y12 and P2Y1 receptors was determined by co-incubation with the selective antagonists AR-C69931 and MRS2179 in vitro. P2Y1 and P2Y12 receptor expression on both RNA and protein level were determined, as well as the P2Y12 H1 or H2 haplotypes. Our data suggest that the residual platelet activation of 2MeS-ADP after clopidogrel treatment is partly due to an inadequate antagonistic effect of clopidogrel on the P2Y12 receptor and partly due to activation of the P2Y1 receptor, which is unaffected by clopidogrel. Moreover, a correlation between increased P2Y12 protein expression on platelets and decreased response to clopidogrel was noticed, r2=0.43 (P<0.05). No correlation was found between P2Y12 mRNA levels and clopidogrel resistance, indicating post-transcriptional mechanisms. To achieve additional ADP inhibition in platelets, antagonists directed at the P2Y1 receptor could be more promising than the development of more potent P2Y12 receptor antagonists. PMID:18404433

  14. Luminescence and luminescence quenching of highly efficient Y2Mo4O15:Eu(3+) phosphors and ceramics.

    PubMed

    Janulevicius, Matas; Marmokas, Paulius; Misevicius, Martynas; Grigorjevaite, Julija; Mikoliunaite, Lina; Sakirzanovas, Simas; Katelnikovas, Arturas

    2016-01-01

    A good LED phosphor must possess strong enough absorption, high quantum yields, colour purity, and quenching temperatures. Our synthesized Y2Mo4O15:Eu(3+) phosphors possess all of these properties. Excitation of these materials with near-UV or blue radiation yields bright red emission and the colour coordinates are relatively stable upon temperature increase. Furthermore, samples doped with 50% Eu(3+) showed quantum yields up to 85%, what is suitable for commercial application. Temperature dependent emission spectra revealed that heavily Eu(3+) doped phosphors possess stable emission up to 400 K and lose half of the efficiency only at 515 K. In addition, ceramic disks of Y2Mo4O15:75%Eu(3+) phosphor with thickness of 0.71 and 0.98 mm were prepared and it turned out that they efficiently convert radiation of 375 and 400 nm LEDs to the red light, whereas combination with 455 nm LED yields purple colour. PMID:27180941

  15. Evidence of heterogeneous substructure development during primary creep of Ti-6Al-2Sn-4Zr-2Mo

    SciTech Connect

    Hayes, R.W.; Rhodes, C.; London, B.

    1995-03-15

    Preliminary creep tests conducted on the titanium alloy Ti-6Al-2Sn-4Zr-2Mo show that both primary creep strain and the minimum strain rate decreases with decreasing volumes of primary alpha phase in the microstructure. This is in agreement with well established trends. The authors have suggested a relationship between the initial dislocation source density and the primary creep behavior and have pointed toward some microstructural variables which may give rise to a high initial dislocation source density. Measurements of anelastic backflow and the characterization of the kinetics of the backflow process indicates that the Ti-6Al-2Sn-4Zr-2Mo exhibits very similar behavior to that of pure FCC aluminum, copper and lead. It is suggested that the anelastic backflow provides direct evidence of a heterogeneous substructure and a nonuniform distribution of stresses within the material which drives the backflow process. The backflow process is discussed along the lines of what has been discussed regarding time dependent anelastic backflow in high purity FCC Metals. Finally, the apparent creep activation energy estimated from creep tests at two temperatures at constant initial applied stress indicates that creep under the present experimental conditions is diffusion controlled. At present no specific mechanism can be defined. More definitive and extensive work is planned in order to better address the issues regarding primary creep in titanium alloys.

  16. Luminescence and luminescence quenching of highly efficient Y2Mo4O15:Eu3+ phosphors and ceramics

    PubMed Central

    Janulevicius, Matas; Marmokas, Paulius; Misevicius, Martynas; Grigorjevaite, Julija; Mikoliunaite, Lina; Sakirzanovas, Simas; Katelnikovas, Arturas

    2016-01-01

    A good LED phosphor must possess strong enough absorption, high quantum yields, colour purity, and quenching temperatures. Our synthesized Y2Mo4O15:Eu3+ phosphors possess all of these properties. Excitation of these materials with near-UV or blue radiation yields bright red emission and the colour coordinates are relatively stable upon temperature increase. Furthermore, samples doped with 50% Eu3+ showed quantum yields up to 85%, what is suitable for commercial application. Temperature dependent emission spectra revealed that heavily Eu3+ doped phosphors possess stable emission up to 400 K and lose half of the efficiency only at 515 K. In addition, ceramic disks of Y2Mo4O15:75%Eu3+ phosphor with thickness of 0.71 and 0.98 mm were prepared and it turned out that they efficiently convert radiation of 375 and 400 nm LEDs to the red light, whereas combination with 455 nm LED yields purple colour. PMID:27180941

  17. Upconversion Luminescence Properties of Y2Mo4O15: Yb3+, Er3+ by Solid State Combustion Method.

    PubMed

    Jiang, Tao; Xing, Mingming; Fu, Yao; Tian, Ying; Luo, Xixian

    2016-04-01

    The Yb3+ and Er3+ co-doped yttrium molybdenum oxide upconversion phosphors were prepared by the solid state combustion method using urea as fuel at ignition temperature of 550 °C. The upconversion phosphors were characterized by X-ray diffraction (XRD), scanning electronic microscope (SEM), and photoluminescence spectra XRD results revealed the samples were pure monoclinic Y2Mo4O15 phases when the sintering temperature was 700 °C. SEM micrographs illustrated particle size distribution was almost uniform with an average particle diameter of about 0.5-1.0 µm. The obtained Y2MO4O15: Yb3+, Er3+ presents bright and pure green upconversion luminescence during daylight pumping under 980 nm LD. According to the analysis of upconversion luminescent mechanism, the cross relaxation processes of Er3+ ions restrained the electron population of red emission energy level, which not only increased the green light upconversion emissions fluorescent branching ratio (IGIR = 153:1) but also enhanced the efficiency and purity of green light emissions. PMID:27451756

  18. Luminescence and luminescence quenching of highly efficient Y2Mo4O15:Eu3+ phosphors and ceramics

    NASA Astrophysics Data System (ADS)

    Janulevicius, Matas; Marmokas, Paulius; Misevicius, Martynas; Grigorjevaite, Julija; Mikoliunaite, Lina; Sakirzanovas, Simas; Katelnikovas, Arturas

    2016-05-01

    A good LED phosphor must possess strong enough absorption, high quantum yields, colour purity, and quenching temperatures. Our synthesized Y2Mo4O15:Eu3+ phosphors possess all of these properties. Excitation of these materials with near-UV or blue radiation yields bright red emission and the colour coordinates are relatively stable upon temperature increase. Furthermore, samples doped with 50% Eu3+ showed quantum yields up to 85%, what is suitable for commercial application. Temperature dependent emission spectra revealed that heavily Eu3+ doped phosphors possess stable emission up to 400 K and lose half of the efficiency only at 515 K. In addition, ceramic disks of Y2Mo4O15:75%Eu3+ phosphor with thickness of 0.71 and 0.98 mm were prepared and it turned out that they efficiently convert radiation of 375 and 400 nm LEDs to the red light, whereas combination with 455 nm LED yields purple colour.

  19. The Molecular Mechanism of P2Y1 Receptor Activation.

    PubMed

    Yuan, Shuguang; Chan, H C Stephen; Vogel, Horst; Filipek, Slawomir; Stevens, Raymond C; Palczewski, Krzysztof

    2016-08-22

    Human purinergic G protein-coupled receptor P2Y1 (P2Y1 R) is activated by adenosine 5'-diphosphate (ADP) to induce platelet activation and thereby serves as an important antithrombotic drug target. Crystal structures of P2Y1 R revealed that one ligand (MRS2500) binds to the extracellular vestibule of this GPCR, whereas another (BPTU) occupies the surface between transmembrane (TM) helices TM2 and TM3. We introduced a total of 20 μs all-atom long-timescale molecular dynamic (MD) simulations to inquire why two molecules in completely different locations both serve as antagonists while ADP activates the receptor. Our results indicate that BPTU acts as an antagonist by stabilizing extracellular helix bundles leading to an increase of the lipid order, whereas MRS2500 blocks signaling by occupying the ligand binding site. Both antagonists stabilize an ionic lock within the receptor. However, binding of ADP breaks this ionic lock, forming a continuous water channel that leads to P2Y1 R activation. PMID:27460867

  20. The Molecular Mechanism of P2Y1 Receptor Activation

    PubMed Central

    Chan, H. C. Stephen; Vogel, Horst; Filipek, Slawomir

    2016-01-01

    Human purinergic G protein-coupled receptor P2Y1 (P2Y1R) is activated by adenosine 5’-diphosphate (ADP) to induce platelet activation and thereby serves as an important antithrombotic drug target. Crystal structures of P2Y1R revealed that one ligand (MRS2500) binds to the extracellular vestibule of this GPCR, whereas another (BPTU) occupies the surface between transmembrane (TM) helices TM2 and TM3. We introduced a total of 20 µs all-atom long-timescale molecular dynamic (MD) simulations to inquire why two molecules in completely different locations both serve as antagonists while ADP activates the receptor. Our results indicate that BPTU acts as an antagonist by stabilizing extracellular helix bundles leading to an increase of the lipid order, whereas MRS2500 blocks signaling by occupying the ligand binding site. Both antagonists stabilize an ionic lock within the receptor. However, binding of ADP breaks this ionic lock, forming a continuous water channel that leads to P2Y1R activation. PMID:27460867

  1. Functionalized Congeners of P2Y1 Receptor Antagonists:

    SciTech Connect

    de Castro, Sonia; Maruoka, Hiroshi; Hong, Kunlun; Kilbey, II, S Michael; Costanzi, Stefano; Hechler, Béatrice; Gachet, Christian; Harden, T. Kendall; Jacobson, Kenneth A.

    2010-01-01

    The P2Y{sub 1} receptor is a prothrombotic G protein-coupled receptor (GPCR) activated by ADP. Preference for the North (N) ring conformation of the ribose moiety of adenine nucleotide 3',5'-bisphosphate antagonists of the P2Y{sub 1} receptor was established by using a ring-constrained methanocarba (a bicyclo[3.1.0]hexane) ring as a ribose substitute. A series of covalently linkable N{sup 6}-methyl-(N)-methanocarba-2'-deoxyadenosine-3',5'-bisphosphates containing extended 2-alkynyl chains was designed, and binding affinity at the human (h) P2Y{sub 1} receptor determined. The chain of these functionalized congeners contained hydrophilic moieties, a reactive substituent, or biotin, linked via an amide. Variation of the chain length and position of an intermediate amide group revealed high affinity of carboxylic congener 8 (K{sub i} 23 nM) and extended amine congener 15 (K{sub i} 132 nM), both having a 2-(1-pentynoyl) group. A biotin conjugate 18 containing an extended {epsilon}-aminocaproyl spacer chain exhibited higher affinity than a shorter biotinylated analogue. Alternatively, click coupling of terminal alkynes of homologous 2-dialkynyl nucleotide derivatives to alkyl azido groups produced triazole derivatives that bound to the P2Y{sub 1} receptor following deprotection of the bisphosphate groups. The preservation of receptor affinity of the functionalized congeners was consistent with new P2Y{sub 1} receptor modeling and ligand docking. Attempted P2Y{sub 1} antagonist conjugation to PAMAM dendrimer carriers by amide formation or palladium-catalyzed reaction between an alkyne on the dendrimer and a 2-iodopurine-derivatized nucleotide was unsuccessful. A dialkynyl intermediate containing the chain length favored in receptor binding was conjugated to an azide-derivatized dendrimer, and the conjugate inhibited ADP-promoted human platelet aggregation. This is the first example of attaching a strategically functionalized P2Y receptor antagonist to a PAMAM dendrimer to

  2. High-temperature behavior of dicesium molybdate Cs{sub 2}MoO{sub 4}: Implications for fast neutron reactors

    SciTech Connect

    Wallez, Gilles; Raison, Philippe E.; Smith, Anna L.; Clavier, Nicolas

    2014-07-01

    Dicesium molybdate (Cs{sub 2}MoO{sub 4})'s thermal expansion and crystal structure have been investigated herein by high temperature X ray diffraction in conjunction with Raman spectroscopy. This first crystal-chemical insight at high temperature is aimed at predicting the thermostructural and thermomechanical behavior of this oxide formed by the accumulation of Cs and Mo fission products at the periphery of nuclear fuel rods in sodium-cooled fast reactors. Within the temperature range of the fuel's rim, Cs{sub 2}MoO{sub 4} becomes hexagonal P6{sub 3}/mmc, with disordered MoO{sub 4} tetrahedra and 2D distribution of Cs–O bonds that makes thermal axial expansion both large (50≤α{sub l}≤70 10{sup −6} °C{sup −1}, 500–800 °C) and highly anisotropic (α{sub c}−α{sub a}=67×10{sup −6} °C{sup −1}, hexagonal form). The difference with the fuel's expansion coefficient is of potential concern with respect to the cohesion of the Cs{sub 2}MoO{sub 4} surface film and the possible release of cesium radionuclides in accidental situations. - Graphical abstract: The weakness of the Cs–O bonds and the disordering of the MoO{sub 4} tetrahedra array in the high-temperature form are responsible for the huge thermal expansion of Cs{sub 2}MoO{sub 4} along the c-axis. - Highlights: • Thermomechanical behavior of Cs{sub 2}MoO{sub 4} fission products compound is studied. • High-temperature form of Cs{sub 2}MoO{sub 4} is characterized by XRD and Raman. • Thermal expansion appears very high and anisotropic. • Cohesion between Cs{sub 2}MoO{sub 4} and nuclear fuel seems questionable, and Cs release is expected.

  3. Automated Drusen Segmentation and Quantification in SD-OCT Images

    PubMed Central

    Chen, Qiang; Leng, Theodore; Zheng, Luoluo; Kutzscher, Lauren; Ma, Jeffrey; de Sisternes, Luis; Rubin, Daniel L.

    2013-01-01

    Spectral domain optical coherence tomography (SD-OCT) is a useful tool for the visualization of drusen, a retinal abnormality seen in patients with age-related macular degeneration (AMD); however, objective assessment of drusen is thwarted by the lack of a method to robustly quantify these lesions on serial OCT images. Here, we describe an automatic drusen segmentation method for SD-OCT retinal images, which leverages a priori knowledge of normal retinal morphology and anatomical features. The highly reflective and locally connected pixels located below the retinal nerve fiber layer (RNFL) are used to generate a segmentation of the retinal pigment epithelium (RPE) layer. The observed and expected contours of the RPE layer are obtained by interpolating and fitting the shape of the segmented RPE layer, respectively. The areas located between the interpolated and fitted RPE shapes (which have nonzero area when drusen occurs) are marked as drusen. To enhance drusen quantification, we also developed a novel method of retinal projection to generate an en face retinal image based on the RPE extraction, which improves the quality of drusen visualization over the current approach to producing retinal projections from SD-OCT images based on a summed-voxel projection (SVP), and it provides a means of obtaining quantitative features of drusen in the en face projection. Visualization of the segmented drusen is refined through several post-processing steps, drusen detection to eliminate false positive detections on consecutive slices, drusen refinement on a projection view of drusen, and drusen smoothing. Experimental evaluation results demonstrate that our method is effective for drusen segmentation. In a preliminary analysis of the potential clinical utility of our methods, quantitative drusen measurements, such as area and volume, can be correlated with the drusen progression in non-exudative AMD, suggesting that our approach may produce useful quantitative imaging biomarkers

  4. Spontaneous polarization and pyroelectric effect in the improper ferroelectrics-ferroelastics Gd2(MoO4)3 and Tb2(MoO4)3 at low temperatures

    NASA Astrophysics Data System (ADS)

    Matyjasik, S.; Shaldin, Yu. V.

    2013-11-01

    The experimental variations in the spontaneous polarization ΔPs(T) and pyroelectric coefficient γs(T) for Gd2(MoO4)3 (GMO) and Tb2(MoO4)3 (TMO) at low temperatures reported here differ from those for intrinsic ferroelectrics. A fundamental difference is found in the repolarization behavior of samples of GMO and TMO at fixed temperatures of 300 and 4.2 K. While the single domain formation temperature essentially has no effect on the measurements for TMO, a fundamental difference is observed in the case of GMO: single domain formation in the latter at 4.2 K leads to an order of magnitude increase in ΔPs at T > 85 K and distinct anomalies are observed in γs(T), at one of which the pyroelectric coefficient reaches a record peak of 3 × 10-4 C/(m2.K) at T = 25 K. At T = 200 K the pyroelectric coefficients equal -1.45 and -1.8 in units of 10-6 C/(m2.K). Based on these results and taking published data on the rotational structural transformation in the (001) plane and symmetry considerations into account, we propose a crystal physical model for GMO-type improper ferroelectrics consisting of four mesotetrahedra, each of which is made up of three different types (a, b, c) of MoO4 coordination tetrahedra. The physical significance of the pseudodeviator coefficient Q12*, which initiates the phase transition at T > 433 K from one non-centrally symmetric phase (mm2) into another (4¯2m), is discussed in terms of this model.

  5. Reciprocal cross-talk between P2Y1 and P2Y12 receptors at the level of calcium signaling in human platelets.

    PubMed

    Hardy, Adam R; Jones, Matthew L; Mundell, Stuart J; Poole, Alastair W

    2004-09-15

    Adenosine diphosphate (ADP), an important platelet agonist, acts through 2 G-protein-coupled receptors (GPCRs), P2Y(1) and P2Y(12), which signal through Gq and Gi, respectively. There is increasing evidence for cross-talk between signaling pathways downstream of GPCRs and here we demonstrate cross-talk between these 2 ADP receptors in human platelets. We show that P2Y(12) contributes to platelet signaling by potentiating the P2Y(1)-induced calcium response. This potentiation is mediated by 2 mechanisms: inhibition of adenylate cyclase and activation of phosphatidylinositol 3 (PI 3)-kinase. Furthermore, the Src family kinase inhibitor PP1 selectively potentiates the contribution to the calcium response by P2Y(12), although inhibition of adenylate cyclase by P2Y(12) is unaffected. Using PP1 in combination with the inhibitor of PI 3-kinase LY294002, we show that Src negatively regulates the PI 3-kinase-mediated component of the P2Y(12) calcium response. Finally, we were able to show that Src kinase is activated through P2Y(1) but not P2Y(12). Taken together, we present evidence for a complex signaling interplay between P2Y(1) and P2Y(12), where P2Y(12) is able to positively regulate P2Y(1) action and P2Y(1) negatively regulates this action of P2Y(12). It is likely that this interplay between receptors plays an important role in maintaining the delicate balance between platelet activation and inhibition during normal hemostasis. PMID:15187029

  6. An Investigation on the Tribological Performances of the SiO2/MoS2 Hybrid Nanofluids for Magnesium Alloy-Steel Contacts.

    PubMed

    Xie, Hongmei; Jiang, Bin; Liu, Bo; Wang, Qinghang; Xu, Junyao; Pan, Fusheng

    2016-12-01

    Hybrid nano-materials offer potential scope for an increasing numerous novel applications when engineered to deliver availably functional properties. In the present study, the SiO2/MoS2 hybrid nanoparticles with different mass ratios were employed as lubricant additives in the base oil, and their tribological properties were evaluated using a reciprocating ball-on-plate tribometer for magnesium alloy-steel contacts. The results demonstrate that the SiO2/MoS2 hybrid nanoparticles exhibit superior lubrication performances than individual nano-SiO2 or nano-MoS2 even in high load and diverse velocity cases. The optimal SiO2/MoS2 mixing ratio and the concentration of SiO2/MoS2 hybrid nanoparticles in the base oil are 0.25:0.75 and 1.00-1.25 wt%, respectively. The excellent lubrication properties of the SiO2/MoS2 hybrid nanoparticles are attributed to the physical synergistic lubricating actions of nano-SiO2 and nano-MoS2 during the rubbing process. PMID:27416902

  7. Facile synthesis of Z-scheme graphitic-C3N4/Bi2MoO6 nanocomposite for enhanced visible photocatalytic properties

    NASA Astrophysics Data System (ADS)

    Lv, Jiali; Dai, Kai; Zhang, Jinfeng; Geng, Lei; Liang, Changhao; Liu, Qiangchun; Zhu, Guangping; Chen, Chen

    2015-12-01

    The band engineering of visible-light-driven photocatalysts is a promising route for harnessing of effective solar energy to perform high chemical reactions and to treat environmental pollution. In this study, two narrow band gap semiconductor nanomaterials, graphitic carbon nitride (g-C3N4) and Bi2MoO6, were selected and coupled to form series of g-C3N4/Bi2MoO6 photocatalysts. Their structure, light absorption wavelength range, charge transport properties and energy level were investigated. Through perfect manipulation of their composition, enhanced photocatalytic activity of the Z-scheme g-C3N4/Bi2MoO6 photocatalysts with efficient reduction of recombination of photogenerated electrons and holes was achieved. The optimized Z-scheme g-C3N4/Bi2MoO6 photocatalysts with 25 wt%g-C3N4 showed apparent pseudo-first-order rate constant kapp as high as 0.0688 min-1, which was 4.8 times and 8.2 times higher than that of g-C3N4 and Bi2MoO6 photocatalyst, respectively.

  8. Hierarchical MoO2/Mo2C/C Hybrid Nanowires as High-Rate and Long-Life Anodes for Lithium-Ion Batteries.

    PubMed

    Yang, Lichun; Li, Xiang; Ouyang, Yunpeng; Gao, Qingsheng; Ouyang, Liuzhang; Hu, Renzong; Liu, Jun; Zhu, Min

    2016-08-10

    Hierarchical MoO2/Mo2C/C hybrid nanowires (MoO2/Mo2C/C HNWs) have been fabricated through facile calcination of Mo3O10(C6H5NH3)2·2H2O nanowires which serve as both precursors and self-templates. In the MoO2/Mo2C/C HNWs, nanoparticles dispersed in the nanowires are beneficial for Li(+) transportation due to the decreased diffusion paths. Moreover, hybridization with Mo2C and carbon facilitates the electron transfer and increases the structural stability without sacrifice of capacity. As anode materials for lithium-ion batteries, the MoO2/Mo2C/C HNWs exhibit a reversible capacity of 950 mA h g(-1) after 320 cycles at a current density of 200 mA g(-1). Even when cycled at 2000 mA g(-1), they maintained a reversible capacity of 602 mA h g(-1) after 500 cycles. By incorporation of Mo2C and C with MoO2, the MoO2/Mo2C/C HNWs show high-rate capability and long cycle life and can be a promising candidate for lithium-ion battery anodes. PMID:27400758

  9. Effects of oxygen vacancy and N-doping on the electronic and photocatalytic properties of Bi{sub 2}MO{sub 6} (M=Mo, W)

    SciTech Connect

    Lai Kangrong; Wei Wei; Zhu Yingtao; Guo Meng; Dai Ying; Huang Baibiao

    2012-03-15

    The electronic properties of Bi{sub 2}MO{sub 6} (M=Mo and W) are studied by using the first-principles calculations. It is attributed to its smaller electron effective mass that Bi{sub 2}WO{sub 6} has higher photocatalytic activity than Bi{sub 2}MoO{sub 6}. The oxygen vacancy in Bi{sub 2}MO{sub 6} serves as a trapping center of photogenerated electrons and thus is in favor of the photocatalytic efficiency. Nitrogen-doping induces localized structure distortion and thus improves the separation of photogenerated electron-hole pairs. Moreover, band gaps decrease obviously with doping concentration increasing, therefore the photoabsorption edges will give rise to a redshift in Bi{sub 2}MO{sub 6}. - Graphical abstract: The oxygen vacancy in Bi{sub 2}WO{sub 6} serves as a trapping center of photogenerated electrons. Nitrogen-doping improves the separation of photogenerated electron-hole pairs. Moreover, band gaps decrease obviously with doping concentration increasing. Highlights: Black-Right-Pointing-Pointer The oxygen vacancy may serve as a trapping center of photogenerated electrons and thus promote the photocatalytic efficiency. Black-Right-Pointing-Pointer Nitrogen-doping induces localized structure distortion and thus improves the separation of photogenerated electron-hole pair. Black-Right-Pointing-Pointer The band gap decreases obviously with doping concentration increasing and thus the photoabsorption edges will redshift in Bi{sub 2}MO{sub 6}.

  10. Discrete Li-occupation versus pseudo-continuous Na-occupation and their relationship with structural change behaviors in Fe2(MoO4)3

    NASA Astrophysics Data System (ADS)

    Yue, Ji-Li; Zhou, Yong-Ning; Shi, Si-Qi; Shadike, Zulipiya; Huang, Xuan-Qi; Luo, Jun; Yang, Zhen-Zhong; Li, Hong; Gu, Lin; Yang, Xiao-Qing; Fu, Zheng-Wen

    2015-03-01

    The key factors governing the single-phase or multi-phase structural change behaviors during the intercalation/deintercalation of guest ions have not been well studied and understood yet. Through systematic studies of orthorhombic Fe2(MoO4)3 electrode, two distinct guest ion occupation paths, namely discrete one for Li and pseudo-continuous one for Na, as well as their relationship with single-phase and two-phase modes for Na+ and Li+, respectively during the intercalation/deintercalation process have been demonstrated. For the first time, the direct atomic-scale observation of biphasic domains (discrete occupation) in partially lithiated Fe2(MoO4)3 and the one by one Na occupation (pseudo-continuous occupation) at 8d sites in partially sodiated Fe2(MoO4)3 are obtained during the discharge processes of Li/Fe2(MoO4)3 and Na/Fe2(MoO4)3 cells respectively. Our combined experimental and theoretical studies bring the new insights for the research and development of intercalation compounds as electrode materials for secondary batteries.

  11. An Investigation on the Tribological Performances of the SiO2/MoS2 Hybrid Nanofluids for Magnesium Alloy-Steel Contacts

    NASA Astrophysics Data System (ADS)

    Xie, Hongmei; Jiang, Bin; Liu, Bo; Wang, Qinghang; Xu, Junyao; Pan, Fusheng

    2016-07-01

    Hybrid nano-materials offer potential scope for an increasing numerous novel applications when engineered to deliver availably functional properties. In the present study, the SiO2/MoS2 hybrid nanoparticles with different mass ratios were employed as lubricant additives in the base oil, and their tribological properties were evaluated using a reciprocating ball-on-plate tribometer for magnesium alloy-steel contacts. The results demonstrate that the SiO2/MoS2 hybrid nanoparticles exhibit superior lubrication performances than individual nano-SiO2 or nano-MoS2 even in high load and diverse velocity cases. The optimal SiO2/MoS2 mixing ratio and the concentration of SiO2/MoS2 hybrid nanoparticles in the base oil are 0.25:0.75 and 1.00-1.25 wt%, respectively. The excellent lubrication properties of the SiO2/MoS2 hybrid nanoparticles are attributed to the physical synergistic lubricating actions of nano-SiO2 and nano-MoS2 during the rubbing process.

  12. Discrete Li-occupation versus pseudo-continuous Na-occupation and their relationship with structural change behaviors in Fe2(MoO4)3

    PubMed Central

    Yue, Ji-Li; Zhou, Yong-Ning; Shi, Si-Qi; Shadike, Zulipiya; Huang, Xuan-Qi; Luo, Jun; Yang, Zhen-Zhong; Li, Hong; Gu, Lin; Yang, Xiao-Qing; Fu, Zheng-Wen

    2015-01-01

    The key factors governing the single-phase or multi-phase structural change behaviors during the intercalation/deintercalation of guest ions have not been well studied and understood yet. Through systematic studies of orthorhombic Fe2(MoO4)3 electrode, two distinct guest ion occupation paths, namely discrete one for Li and pseudo-continuous one for Na, as well as their relationship with single-phase and two-phase modes for Na+ and Li+, respectively during the intercalation/deintercalation process have been demonstrated. For the first time, the direct atomic-scale observation of biphasic domains (discrete occupation) in partially lithiated Fe2(MoO4)3 and the one by one Na occupation (pseudo-continuous occupation) at 8d sites in partially sodiated Fe2(MoO4)3 are obtained during the discharge processes of Li/Fe2(MoO4)3 and Na/Fe2(MoO4)3 cells respectively. Our combined experimental and theoretical studies bring the new insights for the research and development of intercalation compounds as electrode materials for secondary batteries. PMID:25744589

  13. Microstructure investigation of 13Cr-2Mo ODS steel components obtained by high voltage electric discharge compaction technique

    SciTech Connect

    Bogachev, Igor; Yudin, Artem; Grigoryev, Evgeniy; Chernov, Ivan; Staltsov, Maxim; Khasanov, Oleg; Olevsky, Eugene

    2015-11-02

    Refractory oxide dispersion strengthened 13Cr-2Mo steel powder was successfully consolidated to near theoretical density using high voltage electric discharge compaction. Cylindrical samples with relative density from 90% to 97% and dimensions of 10 mm in diameter and 10–15 mm in height were obtained. Consolidation conditions such as pressure and voltage were varied in some ranges to determine the optimal compaction regime. Three different concentrations of yttria were used to identify its effect on the properties of the samples. It is shown that the utilized ultra-rapid consolidation process in combination with high transmitted energy allows obtaining high density compacts, retaining the initial structure with minimal grain growth. The experimental results indicate some heterogeneity of the structure which may occur in the external layers of the tested samples due to various thermal and electromagnetic in-processing effects. As a result, the choice of the optimal parameters of the consolidation enables obtaining samples of acceptable quality.

  14. Chemical Properties of the Cu(In,Ga)Se2/Mo/glass Interfaces in Thin Film Solar Cells

    SciTech Connect

    Weinhardt, L.; Blum, M.; Bar, M.; Heske, C.; Fuchs, O.; Umbach, E.; Denlinger, J. D.; Ramanathan, K.; Noufi, R.

    2007-01-01

    The Cu(In,Ga)Se{sub 2}/Mo and the Mo/glass interfaces in high efficiency thin film solar cells have been investigated by surface-sensitive photoelectron spectroscopy and bulk-sensitive X-ray emission spectroscopy. The interfaces were accessed by a suitable lift-off technique. Our experiments show a strong Se diffusion from the absorber into the Mo film, suggesting the formation of a MoSe{sub 2} layer in the surface-near region of the back contact. In addition, we find a Ga diffusion into the Mo back contact, while no diffusion of In and Cu occurs. Furthermore, we derive a detailed picture of the Na distribution near the back and front side of the Cu(In,Ga)Se{sub 2} absorber.

  15. Synthesis and characterisation of new MO(OH)2 (M = Zr, Hf) oxyhydroxides and related Li2MO3 salts.

    PubMed

    Baklanova, Yana V; Denisova, Tatyana A; Maksimova, Lidiya G; Tyutyunnik, Alexander P; Baklanova, Inna V; Shein, Igor R; Neder, Reinhard B; Tarakina, Nadezda V

    2014-02-21

    Two new solid MO(OH)2 (M = Zr, Hf) oxyhydroxides have been synthesised by an ion-exchange reaction from Li2MO3 (M = Zr, Hf) precursors obtained by a citrate combustion technique. The crystal structure of the oxyhydroxides has been solved by direct methods and refined using Rietveld full profile fitting based on X-ray powder diffraction data. Both oxyhydroxides crystallize in a P2(1)/c monoclinic unit cell and have a structure resembling that of the related salts. Detailed characterisation of the fine-structure features and chemical bonding in precursors and oxyhydroxide powders has been performed using vibrational spectroscopy, nuclear magnetic resonance spectroscopy, scanning electron microscopy, pair distribution function analysis and quantum-chemical modelling. PMID:24343584

  16. Semantic description of drama scene by using SD-form

    NASA Astrophysics Data System (ADS)

    Niimi, Michiharu; Kawaguchi, Eiji

    1997-01-01

    Multimedia data processing is becoming more and more a central concern among the people who have been working on image processing. Multimedia database retrieval is one of such a problem. A foreign language study assisting system is a good example for a multimedia data base design. Because each language depends on conversational situation such as topic and speech intention as well as place of conversation.In that case, we can not neglect the semantic aspect of multimedia information. The author's group has already proposed a semantic structure description form, called the SD-form, of the language meaning. They studied the feasibility of its application to natural language generation, story understanding, and conversational text retrieval systems. This paper presents our new attempt to expand our previous system from a text database systems to a multimedia database system which include motion picture, speech sound as well as language text. the source of the data in this project is a series of bilingual TV drama broadcasted in Japan. The most important point is this attempt is that each video scene is described by a set of SD-forms by which scenes are retrieved semantically.

  17. FUSE Observations of He-rich sdB Stars

    NASA Technical Reports Server (NTRS)

    Swiegart, A. V.; Lanz, T.; Brown, T. M.; Hubeny, I.; Landsman, W. B.

    2003-01-01

    Most subdwarf B stars are extremely deficient in helium and selected light elements, but a minority are helium-rich. New evolutionary calculations suggest that these helium-rich sdB stars are the result of a delayed helium-core flash on the white dwarf cooling curve, which leads to extensive mixing between the hydrogen envelope and helium core. Such mixed stars should show greatly enhanced helium and carbon with respect to the other heavy elements. We have recently obtained FUSE spectra of two helium-rich sdB stars, PG1544+488 and JL87, revealing huge C Ill lines at 977 and 1176 A. Our analysis shows that PG1544+488 has a surface composition of 97% He, 2% C, and 1% N, in agreement with the new evolutionary scenario. While JL87 also reveals a large enrichment in carbon and nitrogen (1.4% and 0.4%, respectively), there is still a significant amount of hydrogen in its atmosphere.

  18. Digital LAMP in a sample self-digitization (SD) chip

    PubMed Central

    Herrick, Alison M.; Dimov, Ivan K.; Lee, Luke P.; Chiu, Daniel T.

    2012-01-01

    This paper describes the realization of digital loop-mediated DNA amplification (dLAMP) in a sample self-digitization (SD) chip. Digital DNA amplification has become an attractive technique to quantify absolute concentrations of DNA in a sample. While digital polymerase chain reaction is still the most widespread implementation, its use in resource—limited settings is impeded by the need for thermal cycling and robust temperature control. In such situations, isothermal protocols that can amplify DNA or RNA without thermal cycling are of great interest. Here, we showed the successful amplification of single DNA molecules in a stationary droplet array using isothermal digital loop-mediated DNA amplification. Unlike most (if not all) existing methods for sample discretization, our design allows for automated, loss-less digitization of sample volumes on-chip. We demonstrated accurate quantification of relative and absolute DNA concentrations with sample volumes of less than 2 μl. We assessed the homogeneity of droplet size during sample self-digitization in our device, and verified that the size variation was small enough such that straightforward counting of LAMP-active droplets sufficed for data analysis. We anticipate that the simplicity and robustness of our SD chip make it attractive as an inexpensive and easy-to-operate device for DNA amplification, for example in point-of-care settings. PMID:22399016

  19. Oxidation and alpha-case formation in Ti–6Al–2Sn–4Zr–2Mo alloy

    SciTech Connect

    Gaddam, Raghuveer; Sefer, Birhan; Pederson, Robert; Antti, Marta-Lena

    2015-01-15

    Isothermal heat treatments in ambient air were performed on wrought Ti–6Al–2Sn–4Zr–2Mo (Ti-6242) material at 500, 593 and 700°C for times up to 500 h. In the presence of oxygen at elevated temperatures simultaneous reactions occurred in Ti-6242 alloy, which resulted in the formation of an oxide scale and a layer with higher oxygen concentration (termed as alpha-case). Total weight gain analysis showed that there was a transition in the oxidation kinetics. At 500°C, the oxidation kinetics obeyed a cubic relationship up to 200 h and thereafter changed to parabolic at prolonged exposure times. At 593°C, it followed a parabolic relationship. After heat treatment at 700°C, the oxidation obeyed a parabolic relationship up to 200 h and thereafter changed to linear at prolonged exposure times. The observed transition is believed to be due to the differences observed in the oxide scale. The activation energy for parabolic oxidation was estimated to be 157 kJ/mol. In addition, alpha-case layer was evaluated using optical microscope, electron probe micro-analyser and microhardness tester. The thickness of the alpha-case layer was found to be a function of temperature and time, increasing proportionally, and following a parabolic relationship. The activation energy for the formation of alpha-case layer was estimated to be 153 kJ/mol. - Highlights: • Transition in oxidation kinetics was observed in Ti–6Al–2Sn–4Zr–2Mo alloy in the temperature range 500–700°C. • The activation energy for parabolic oxidation and for alpha-case formation is about 157 kJ/mol and 153 kJ/mol. • Thickness of alpha-case layer estimated by optical microscopy and electron probe microanalysis is comparable.

  20. Materials properties of out-of-plane heterostructures of MoS2-WSe2 and WS2-MoSe2

    NASA Astrophysics Data System (ADS)

    Amin, Bin; Kaloni, Thaneshwor P.; Schreckenbach, Georg; Freund, Michael S.

    2016-02-01

    Based on first-principles calculations, the materials properties (structural, electronic, vibrational, and optical properties) of out-of-plane heterostructures formed from the transition metal dichalcogenides, specifically MoS2-WSe2 and WS2-MoSe2, were investigated. The heterostructures of MoS2-WSe2 and WS2-MoSe2 are found to be direct and indirect band gap semiconductors, respectively. However, a direct band gap in the WS2-MoSe2 heterostructure can be achieved by applying compressive strain. Furthermore, the excitonic peaks in both monolayer and bilayer heterostructures are calculated to understand the optical behavior of these systems. The suppression of the optical spectrum with respect to the corresponding monolayers is due to interlayer charge transfer. The stability of the systems under study is confirmed by performing phonon spectrum calculations.

  1. Interlayer Transition and Infrared Photodetection in Atomically Thin Type-II MoTe2/MoS2 van der Waals Heterostructures.

    PubMed

    Zhang, Kenan; Zhang, Tianning; Cheng, Guanghui; Li, Tianxin; Wang, Shuxia; Wei, Wei; Zhou, Xiaohao; Yu, Weiwei; Sun, Yan; Wang, Peng; Zhang, Dong; Zeng, Changgan; Wang, Xingjun; Hu, Weida; Fan, Hong Jin; Shen, Guozhen; Chen, Xin; Duan, Xiangfeng; Chang, Kai; Dai, Ning

    2016-03-22

    We demonstrate the type-II staggered band alignment in MoTe2/MoS2 van der Waals (vdW) heterostructures and an interlayer optical transition at ∼1.55 μm. The photoinduced charge separation between the MoTe2/MoS2 vdW heterostructure is verified by Kelvin probe force microscopy (KPFM) under illumination, density function theory (DFT) simulations and photoluminescence (PL) spectroscopy. Photoelectrical measurements of MoTe2/MoS2 vdW heterostructures show a distinct photocurrent response in the infrared regime (1550 nm). The creation of type-II vdW heterostructures with strong interlayer coupling could improve our fundamental understanding of the essential physics behind vdW heterostructures and help the design of next-generation infrared optoelectronics. PMID:26950255

  2. Electrochemical Properties and Sodium-Storage Mechanism of Ag2 Mo2 O7 as the Anode Material for Sodium-Ion Batteries.

    PubMed

    Chen, Nan; Gao, Yu; Zhang, Meina; Meng, Xing; Wang, Chunzhong; Wei, Yingjin; Du, Fei; Chen, Gang

    2016-05-17

    Silver molybdate, Ag2 Mo2 O7 , has been prepared by a conventional solid-state reaction. Its electrochemical properties as an anode material for sodium-ion batteries (SIBs) have been comprehensively examined by means of galvanostatic charge-discharge cycling, cyclic voltammetry, and rate performance measurements. At operating voltages between 3.0 and 0.01 V, the electrode delivered a reversible capacity of nearly 190 mA h g(-1) at a current density of 20 mA g(-1) after 70 cycles. Ag2 Mo2 O7 also demonstrated a good rate capability and long-term cycle stability, the capacity reaching almost 100 mA h g(-1) at a current density of 500 mA g(-1) , with a capacity retention of 55 % over 1000 cycles. Moreover, the sodium storage process of Ag2 Mo2 O7 has been investigated by means of ex situ XRD, Raman spectroscopy, and HRTEM. Interestingly, the anode decomposes into Ag metal and Na2 MoO4 during the initial discharge process, and then Na(+) ions are considered to be inserted into/extracted from the Na2 MoO4 lattice in the subsequent cycles governed by an intercalation/deintercalation mechanism. Ex situ HRTEM images revealed that Ag metal not only remains unchanged during the sodiation/desodiation processes, but is well dispersed throughout the amorphous matrix, thereby greatly improving the electronic conductivity of the working electrode. The "in situ" decomposition behavior of Ag2 Mo2 O7 is distinct from that of chemically synthesized, metal-nanoparticle-coated electrode materials, and provides strong supplementary insight into the mechanism of such new anode materials for SIBs and may set a precedent for the design of further materials. PMID:27061105

  3. Size effect on the magnetic and electronic properties of the monolayer lateral hetero-junction WS2-MoS2 nanoribbon

    NASA Astrophysics Data System (ADS)

    Wen, Yan-Ni; Xia, Ming-Gang; Zhang, Sheng-Li

    2016-05-01

    By using the VASP, we studied the magnetic and electronic properties of the monolayer lateral hetero-junction WS2-MoS2-nanoribbons (WS2-MoS2-NRs). Our results show that the NRs' edge chirality and width affect significantly its magnetic and electronic properties. The monolayer lateral hetero-junction ZZ-WS2-MoS2-NRs(ZZ: zigzag) exhibitmetallic behavior and have considerable magnetic moment. Their magnetic moments decrease in the order of Nz = 2, 6 and 4 (the width of NRs). While, the magnetic moment decreases with the increased rz (the number of the Mo-S chains, rz ≠ 0 and rz ≠ Nz) at the same width Nz. The NA-AC-WS2-NR (AC: armchair) and NA-AC-WS2-MoS2-NR-1 (the number of the Mo-S chain is 1) show metallic behavior when NA = 3 (the width of NRs). The other monolayer lateral hetero-junction AC-WS2-MoS2-NRs remain the nonmagnetic and semiconductingbehavior as bulk. But they are indirect band-gap except for the NA = 3, rA = 2 (the number of the Mo-S chains) and NA = 7, rA = 0 when NA < 9. However they are direct band-gap when NA ≥ 9. Their lowest and highest band gaps are 0.150 eV and 0.581 eV, respectively. These unique magnetic and electronic properties will provide guidanceon the WS2-MoS2 hetero-junction application in nanodevice.

  4. Oxygen miscibility gap and spin glass formation in the pyrochlore Lu{sub 2}Mo{sub 2}O{sub 7}

    SciTech Connect

    Clark, L.; Ritter, C.; Harrison, A.; Attfield, J.P.

    2013-07-15

    Rare earth (R) molybdate pyrochlores, R{sub 2}Mo{sub 2}O{sub 7}, are of interest as frustrated magnets. Polycrystalline samples of Lu{sub 2}Mo{sub 2}O{sub 7−x} prepared at 1600 °C display a coexistence of cubic pyrochlore phases. Rietveld fits to powder neutron diffraction data and chemical analyses show that the miscibility gap is between a stoichiometric x=0 and an oxygen-deficient x≈0.4 phase. Lu{sub 2}Mo{sub 2}O{sub 7} behaves as a spin glass material, with a divergence of field cooled and zero field cooled DC magnetic susceptibilities at a spin freezing temperature T{sub f}=16 K, that varies with frequency in AC measurements following a Vogel–Fulcher law. Lu{sub 2}Mo{sub 2}O{sub 6.6} is more highly frustrated spin glass and has T{sub f}=20 K. - Graphical abstract: The cubic Lu{sub 2}Mo{sub 2}O{sub 7−x} system exhibits a miscibility gap between coexisting pyrochlore phases at 1600 °C. Neutron powder diffraction refinement and chemical analysis shows that the gap separates stoichiometric x=0 and oxygen-deficient x≈0.4 phases. Lu{sub 2}Mo{sub 2}O{sub 7−x} has a frustrated spin glass ground state that is sensitive to the oxygen content. - Highlights: • The cubic Lu{sub 2}Mo{sub 2}O{sub 7−x} system has a miscibility gap between coexisting pyrochlore phases at 1600 °C. • Neutron powder diffraction shows that the gap separates x=0 and oxygen-deficient x≈0.4 phases. • Lu{sub 2}Mo{sub 2}O{sub 7−x} has a frustrated spin glass ground state that is sensitive to the oxygen content.

  5. Photocatalytic activity of Fe{sub 3}O{sub 4}/Bi{sub 2}MoO{sub 6} composite in Rhodamine B decomposition

    SciTech Connect

    Liu, Jue; Zeng, Min E-mail: rhyu@buaa.edu.cn; Dong, Hangrong; Liu, Xiaofang; Yu, Ronghai E-mail: rhyu@buaa.edu.cn; Wang, Yu; He, Jun

    2015-05-07

    Flower-like Fe{sub 3}O{sub 4}/Bi{sub 2}MoO{sub 6} has been prepared via a facile two-step thermosynthesis method. The composite displays high photocatalytic activity in Rhodamine B decomposition under visible light irradiation. Bi{sub 2}MoO{sub 6} with flower-like structure that has high specific surface area guarantees excellent photocatalytic performance. Fe{sub 3}O{sub 4} retards electron-hole recombination that contributes to photocatalytic property. Further, the stable composite exhibits remarkable reusability due to the incorporation of magnetic particle.

  6. Role of spinal P2Y6 and P2Y11 receptors in neuropathic pain in rats: possible involvement of glial cells

    PubMed Central

    2014-01-01

    Background The participation of spinal P2X receptors in neuropathic pain is well recognized. However, the role of P2Y receptors has been less studied. The purpose of this study was to investigate the contribution of spinal P2Y6,11 receptors following peripheral nerve damage induced by spinal nerve ligation. In addition, we determined the expression of P2Y6,11 receptors in the dorsal spinal cord in presence of the selective P2Y6,11 receptors antagonists. Furthermore, we evaluated the participation of spinal microglia and astrocytes in the pronociceptive role of P2Y6,11 receptors. Results Spinal administration of the selective P2Y6 (MRS2578, 10–100 μM) and P2Y11 (NF340, 0.3–30 μM) receptor antagonists reduced tactile allodynia in spinal nerve ligated rats. Nerve injury increased the expression of P2Y6,11 receptors at 7, 14 and 21 days after injury. Furthermore, intrathecal administration of MRS2578 (100 μM/day) and NF340 (30 μM/day) for 3 days significantly reduced spinal nerve injury-induced increase in P2Y6,11 receptors expression, respectively. Spinal treatment (on day 14 after injury) with minocycline (100 μg/day) or fluorocitrate (1 nmol/day) for 7 days reduced tactile allodynia and spinal nerve injury-induced up-regulation in Iba-1 and GFAP, respectively. In addition, minocycline reduced nerve injury-induced up-regulation in P2Y6,11 receptors whereas that fluorocitrate diminished P2Y11, but not P2Y6, receptors up-regulation. Intrathecal treatment (on day 21 after injury) with the selective P2Y6 (PSB0474, 3–30 μM) and P2Y11 (NF546, 1–10 μM) receptor agonists produced remarkable tactile allodynia in nerve ligated rats previously treated with minocycline or fluorocitrate for 7 days. Conclusions Our data suggest that spinal P2Y6 is present in spinal microglia while P2Y11 receptors are present in both spinal microglia and astrocytes, and both receptors are up-regulated in rats subjected to spinal nerve injury. In addition, our data suggest

  7. Open sd-shell nuclei from first principles

    DOE PAGESBeta

    Jansen, Gustav R.; Signoracci, Angelo J.; Hagen, Gaute; Navratil, Petr

    2016-07-05

    We extend the ab initio coupled-cluster e ective interaction (CCEI) method to open-shell nuclei with protons and neutrons in the valence space, and compute binding energies and excited states of isotopes of neon and magnesium. We employ a nucleon-nucleon and three-nucleon interaction from chiral e ective eld theory evolved to a lower cuto via a similarity renormalization group transformation. We nd good agreement with experiment for binding energies and spectra, while charge radii of neon isotopes are underestimated. For the deformed nuclei 20Ne and 24Mg we reproduce rotational bands and electric quadrupole transitions within uncertainties estimated from an e ectivemore » eld theory for deformed nuclei, thereby demonstrating that collective phenomena in sd-shell nuclei emerge from complex ab initio calculations.« less

  8. Charge radii of neon isotopes across the sd neutron shell

    SciTech Connect

    Marinova, K.; Geithner, W.; Kappertz, S.; Kloos, S.; Kotrotsios, G.; Neugart, R.; Wilbert, S.; Kowalska, M.; Keim, M.; Blaum, K.; Lievens, P.; Simon, H.

    2011-09-15

    We report on the changes in mean square charge radii of unstable neon nuclei relative to the stable {sup 20}Ne, based on the measurement of optical isotope shifts. The studies were carried out using collinear laser spectroscopy on a fast beam of neutral neon atoms. High sensitivity on short-lived isotopes was achieved thanks to nonoptical detection based on optical pumping and state-selective collisional ionization, which was complemented by an accurate determination of the beam kinetic energy. The new results provide information on the structural changes in the sequence of neon isotopes all across the neutron sd shell, ranging from the proton drip line nucleus and halo candidate {sup 17}Ne up to the neutron-rich {sup 28}Ne in the vicinity of the ''island of inversion.'' Within this range the charge radius is smallest for {sup 24}Ne with N=14 corresponding to the closure of the neutron d{sub 5/2} shell, while it increases toward both neutron shell closures, N=8 and N=20. The general trend of the charge radii correlates well with the deformation effects which are known to be large for several neon isotopes. In the neutron-deficient isotopes, structural changes arise from the onset of proton-halo formation for {sup 17}Ne, shell closure in {sup 18}Ne, and clustering effects in {sup 20,21}Ne. On the neutron-rich side the transition to the island of inversion plays an important role, with the radii in the upper part of the sd shell confirming the weakening of the N=20 magic number. The results add new information to the radii systematics of light nuclei where data are scarce because of the small contribution of nuclear-size effects to the isotope shifts which are dominated by the finite-mass effect.

  9. Extracellular ATP inhibits chloride channels in mature mammalian skeletal muscle by activating P2Y1 receptors.

    PubMed

    Voss, Andrew A

    2009-12-01

    ATP is released from skeletal muscle during exercise, a discovery dating back to 1969. Surprisingly, few studies have examined the effects of extracellular ATP on mature mammalian skeletal muscle. This electrophysiological study examined the effects of extracellular ATP on fully innervated rat levator auris longus using two intracellular microelectrodes. The effects of ATP were determined by measuring the relative changes of miniature endplate potentials (mEPPs) and voltage responses to step current pulses in individual muscle fibres. Exposure to ATP (20 microm) prolonged the mEPP falling phase by 31 +/- 7.5% (values +/- s.d., n = 3 fibres). Concurrently, the input resistance increased by 31 +/- 2.0% and the time course of the voltage responses increased by 59 +/- 3.0%. Analogous effects were observed using 2 and 5 microm ATP, and on regions distal from the neuromuscular junction, indicating that physiologically relevant levels of ATP enhanced electrical signalling over the entire muscle fibre. The effects of extracellular ATP were blocked by 200 microm anthracene-9-carboxylic acid, a chloride channel inhibitor, and reduced concentrations of extracellular chloride, indicating that ATP inhibited chloride channels. A high affinity agonist for P2Y receptors, 2-methylthioadenosine-5-O-diphosphate (2MeSADP), induced similar effects to ATP with an EC(50) of 160 +/- 30 nm. The effects of 250 nm2MeSADP were blocked by 500 nmMRS2179, a specific P2Y(1) receptor inhibitor, suggesting that ATP acts on P2Y(1) receptors to inhibit chloride channels. The inhibition of chloride channels by extracellular ATP has implications for muscle excitability and fatigue, and the pathophysiology of myotonias. PMID:19805741

  10. Calmodulin interacts with the platelet ADP receptor P2Y1

    PubMed Central

    Arthur, Jane F.; Shen, Yang; Mu, Fi-Tjen; Leon, Catherine; Gachet, Christian; Berndt, Michael C.; Andrews, Robert K.

    2006-01-01

    P2Y1 [P2 (purinergic type-2)-receptor 1] is a G-protein-coupled ADP receptor that regulates platelet activation and ADP-induced Ca2+ signalling. Studies using P2Y1-knockout mice, Gq-deficient mice or P2Y1-selective inhibitors have previously identified a key role for P2Y1 in pathophysiological thrombus formation at high shear stress. We provide evidence that a positively charged juxtamembrane sequence within the cytoplasmic C-terminal tail of P2Y1 can bind directly to the cytosolic regulatory protein calmodulin. Deletion by mutagenesis of the calmodulin-binding domain of P2Y1 inhibits intracellular Ca2+ flux in transfected cells. These results suggest that the interaction of calmodulin with the P2Y1 C-terminal tail may regulate P2Y1-dependent platelet aggregation. PMID:16848759

  11. Electrical properties of WSe sub 2, WS sub 2, MoSe sub 2, MoS sub 2, and their use as photoanodes in a semiconductor/liquid junction solar cell

    NASA Astrophysics Data System (ADS)

    Kam, K. K.

    1982-12-01

    The electrical resistivity and Hall effect perpendicular to the c-axis of single crystals of n-type WSe2, MoSe2, WS2, and MoS2 were studied in the extrinsic conduction temperatre range (77 K to 300 K). It was found that a single donor energy level is assigned to the crystals of WSe2 and MoSe2, even for crystals from different growth ampules. E/sub D/ = (1-9 + or - 4) MeV for WSe2 and (64 + or - 2) MeV for MoSe2. The electron Hall mobility of these two compounds depends strongly on temperature micron/sub H/ approximately 1/T (2.4) for WSe2 and approximately 1/T(2.6) for MoSe2. For WS2 and MoS2, the results were not as consistent as those for WSe2 and MoSe2. The resistivity anistropy of these two compounds is small, compared to that reported on natural single crystals of MoS2.

  12. P2Y2R Deficiency Attenuates Experimental Autoimmune Uveitis Development

    PubMed Central

    Relvas, Lia Judice M.; Makhoul, Maya; Dewispelaere, Remi; Caspers, Laure; Communi, Didier; Boeynaems, Jean-Marie; Robaye, Bernard; Bruyns, Catherine; Willermain, François

    2015-01-01

    We aimed to study the role of the nucleotide receptor P2Y2R in the development of experimental autoimmune uveitis (EAU). EAU was induced in P2Y2+/+ and P2Y2-/- mice by immunization with IRBP peptide or by adoptive transfer of in vitro restimulated semi-purified IRBP-specific enriched T lymphocytes from spleens and lymph nodes isolated from native C57Bl/6 or P2Y2+/+ and P2Y2-/- immunized mice. Clinical and histological scores were used to grade disease severity. Splenocytes and lymph node cell phenotypes were analyzed using flow cytometry. Semi-purified lymphocytes and MACS-purified CD4+ T lymphocytes from P2Y2+/+ and P2Y2-/- immunized mice were tested for proliferation and cytokine secretion. Our data show that clinical and histological scores were significantly decreased in IRBP-immunized P2Y2-/- mice as in P2Y2-/- mice adoptively transfered with enriched T lymphocytes from C57Bl/6 IRBP-immunized mice. In parallel, naïve C57Bl/6 mice adoptively transferred with T lymphocytes from P2Y2-/- IRBP-immunized mice also showed significantly less disease. No differences in term of spleen and lymph node cell recruitment or phenotype appeared between P2Y2-/- and P2Y2+/+ immunized mice. However, once restimulated in vitro with IRBP, P2Y2-/- T cells proliferate less and secrete less cytokines than the P2Y2+/+ one. We further found that antigen-presenting cells of P2Y2-/- immunized mice were responsible for this proliferation defect. Together our data show that P2Y2-/- mice are less susceptible to mount an autoimmune response against IRBP. Those results are in accordance with the danger model, which makes a link between autoreactive lymphocyte activation, cell migration and the release of danger signals such as extracellular nucleotides. PMID:25692550

  13. The luminescence properties of Bi3+ sensitized Gd2MoO6:RE3+ (RE = Eu or Sm) phosphors for solar spectral conversion

    NASA Astrophysics Data System (ADS)

    Huang, M. N.; Ma, Y. Y.; Huang, X. Y.; Ye, S.; Zhang, Q. Y.

    2013-11-01

    Gd2MoO6:RE3+ (RE = Eu or Sm) and Gd2MoO6:Bi3+, RE3+ (RE = Eu or Sm) phosphors have been synthesized by combustion method. The samples are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), photoluminescence excitation (PLE) and photoluminescence (PL) spectra. By introducing Bi3+ ions into Gd2MoO6:RE3+ (RE = Eu or Sm) phosphors, the excitation bands of Eu3+ and Sm3+ ions are broadened and shifted to short wavelength, meanwhile, the emission intensity are enhanced obviously. The energy transfer from Bi3+ to the activators of Eu3+ or Sm3+ is observed and discussed. In addition, the process of ultraviolet light (250-400 nm) converted into visible light can be achieved by using Gd2MoO6:Bi3+, RE3+ (RE = Eu or Sm) phosphor. These phosphors can be a promising ultraviolet-absorbing luminescent converter to enhance the photoelectrical conversion efficiency of dye-sensitized solar cells (DSSCs).

  14. A hierarchical Zn2Mo3O8 nanodots-porous carbon composite as a superior anode for lithium-ion batteries.

    PubMed

    Zhu, Yanping; Zhong, Yijun; Chen, Gao; Deng, Xiang; Cai, Rui; Li, Li; Shao, Zongping

    2016-08-01

    A hierarchical Zn2Mo3O8 nanodots-porous carbon composite has been successfully synthesized via the ingenious combination of ion exchange and molten salt strategies, and the composite exhibits remarkable performance as an anode material for lithium-ion batteries. PMID:27374699

  15. Chromosomal localization of the human P2y6 purinoceptor gene and phylogenetic analysis of the P2y purinoceptor family.

    PubMed

    Somers, G R; Hammet, F; Woollatt, E; Richards, R I; Southey, M C; Venter, D J

    1997-08-15

    The G-protein-coupled P2Y purinoceptors mediate a variety of physiological effects in response to extracellular nucleotides. With the recent discovery of several new members from a variety of species, the P2Y purinoceptor family now encompasses types P2Y1 to P2Y6. By fluorescence in situ hybridization and utilization of the National Center for Biotechnology Information (NCBI) database, the human P2Y6 gene was localized to chromosome 11q13.5, between polymorphic markers D11S1314 and D11S916. NCBI database analysis of the remaining human P2Y purinoceptor genes revealed that P2Y2 and P2Y6 mapped to within less than 4 cM, and thus constitute the first described chromosomal clustering of this gene family. Phylogenetic analysis of the P2Y purinoceptor family demonstrated the presence of five evolutionary branches and suggests the occurrence of an ancient gene duplication event. PMID:9286708

  16. Photoluminescence properties of a new orange–red emitting Sm{sup 3+}-doped Y{sub 2}Mo{sub 4}O{sub 15} phosphor

    SciTech Connect

    Deng, Huajuan; Zhao, Ze; Wang, Jing; Hei, Zhoufei; Li, Mengxue; Noh, Hyeon Mi; Jeong, Jung Hyun; Yu, Ruijin

    2015-08-15

    A series of novel Y{sub 2}Mo{sub 4}O{sub 15}:xSm{sup 3+} ( (0.01 ≤ x ≤ 0.20) phosphors for white light-emitting (W-LEDs) were successfully prepared by the solid state reaction technology at 973 K for 12 h. X-ray diffraction and photoluminescence spectra were utilized to characterize the structure and luminescence properties of the as-synthesized phosphors. The emission spectra of the Y{sub 2}Mo{sub 4}O{sub 15}:Sm{sup 3+} phosphors consisted of some sharp emission peaks of Sm{sup 3+} ions centered at 565 nm, 605 nm, 650 nm, and 712 nm. The strongest one is located at 605 nm due to {sup 4}G{sub 5/2}–{sup 6}H{sub 7/2} transition of Sm{sup 3+}, generating bright orange–red light. The optimum dopant concentration of Sm{sup 3+} ions in Y{sub 2}Mo{sub 4}O{sub 15}:xSm{sup 3+} is around 5 mol% and the critical transfer distance of Sm{sup 3+} is calculated as 23.32 Å. The CIE chromaticity coordinates of the Y{sub 2}Mo{sub 4}O{sub 15}:0.05Sm{sup 3+} phosphors were located in the orange reddish region. The Y{sub 2}Mo{sub 4}O{sub 15}:Sm{sup 3+} phosphors may be potentially used as red phosphors for white light-emitting diodes. - Graphical abstract: The excitation spectrum of Y{sub 2}Mo{sub 4}O{sub 15}:Sm{sup 3+} is composed of a broad band and some sharp f–f transitions. Under 407 nm excitation, the phosphor presents some sharp emission peaks of Sm{sup 3+} ions. - Highlights: • An orange–red emitting Y{sub 2}Mo{sub 4}O{sub 15}:Sm{sup 3+} phosphor has been firstly synthesized. • Their structures, luminescent properties have also been investigated. • The optical absorption edge for the molybdate lies around 325 nm. • The CIE chromaticity coordinates were located in the orange reddish region.

  17. Effects of the solvent on the structure, morphology and photocatalytic properties of Bi{sub 2}MoO{sub 6} in the solvothermal process

    SciTech Connect

    Bi, Jinhong; Che, Jiangang; Wu, Ling; Liu, Minghua

    2013-06-01

    Graphical abstract: Various nanostructure Bi{sub 2}MoO{sub 6} photocatalysts have been prepared by a solvothermal process via simply altering the used solvent. It is revealed that the type of solvents has a strong influence on the morphology of Bi{sub 2}MoO{sub 6}. This could be understood in terms of the reaction media effect on the crystal growth. The photocatalytic experiments for the decomposition of RhB demonstrate that the samples prepared by different solvents show different photocatalytic activity. The highest photocatalytic activity is obtained by the sample with glycol as solvent. Highlights: ► The used solvent in the synthesis can affect the morphology and size of Bi{sub 2}MoO{sub 6}. ► Different solvent in the reaction leads to different surface area and pore size. ► The highest photocatalytic activity is obtained by the sample prepared in glycol. ► The high activity is mainly due to the large surface area and small particle size. - Abstract: Visible-light-driven photocatalyst Bi{sub 2}MoO{sub 6} was prepared by a solvothermal process with different kinds of solvent including water, isopropanol and ethylene glycol. The obtained samples were characterized by X-ray diffraction technique, N{sub 2}-sorption, UV–vis diffuse reflectance spectra, transmission electron microscopy and Fourier transform infrared spectroscopy. The results revealed that the type of solvent has a strong influence on the morphologies and physico-chemical properties of Bi{sub 2}MoO{sub 6}. Meanwhile, the formation mechanism of Bi{sub 2}MoO{sub 6} with various morphologies was discussed. The photocatalytic activities of Bi{sub 2}MoO{sub 6} photocatalysts were evaluated by the decomposition of rhodamine B (RhB) under visible light irradiation (λ > 420 nm). It was found that the sample prepared with glycol as solvent showed the best performance in the photodegradation of RhB under visible light irradiation. This could be ascribed to the large surface area, unique morphology

  18. Improved Hybrid Genome Assemblies of Two Strains of Bacteroides xylanisolvens, SD_CC_1b and SD_CC_2a, Obtained Using Illumina and 454 Sequencing Technologies

    PubMed Central

    Ramaraj, Thiruvarangan; Sundararajan, Anitha; Schilkey, Faye D.; DelVecchio, Vito G.; Donlon, Mildred; Ziemer, Cherie

    2014-01-01

    Bacteroides xlyanisolvens strains (SD_CC_1b, SD_CC_2a) isolated from human feces were grown on crystalline cellulose. Cellulolytic properties are not common in Bacteroides species. Here, we report improved genome sequences of both of the B. xlyanisolvens strains. PMID:24699955

  19. Improved hybrid genome assemblies of 2 strains of Bacteroides xylanisolvens SD-CC-1b and SD-CC-2a using Illumina and 454 sequencing technologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacteroides xlyanisolvens strains (SD_CC_1b, SD_CC_2a) isolated from human feces were able to grow on crystalline cellulose. Cellulolytic properties are not common in Bacteroides species. Here, we report improved genome sequences of both the B. xlyanisolvens strains....

  20. P2Y Receptors in Alzheimer’s Disease

    PubMed Central

    Erb, Laurie; Cao, Chen; Ajit, Deepa; Weisman, Gary A.

    2014-01-01

    Alzheimer’s disease (AD) is the most common cause of dementia, affecting more than 10% of people over the age of 65. Age is the greatest risk factor for AD, although a combination of genetic, lifestyle and environmental factors also contribute to disease development. Common features of AD are the formation of plaques composed of beta-amyloid peptides (Aβ) and neuronal death in brain regions involved in learning and memory. Although Aβ is neurotoxic, the primary mechanisms by which Aβ affects AD development remain uncertain and controversial. Mouse models overexpressing amyloid precursor protein and Aβ have revealed that Aβ has potent effects on neuroinflammation and cerebral blood flow that contribute to AD progression. Therefore, it is important to consider how endogenous signaling in the brain responds to Aβ and contributes to AD pathology. In recent years, Aβ has been shown to affect ATP release from brain and blood cells and alter the expression of G protein-coupled P2Y receptors that respond to ATP and other nucleotides. Accumulating evidence reveals a prominent role for P2Y receptors in AD pathology, including Aβ production and elimination, neuroinflammation, neuronal function and cerebral blood flow. PMID:25179475

  1. Erbium-doped fiber laser passively mode locked with few-layer WSe2/MoSe2 nanosheets

    NASA Astrophysics Data System (ADS)

    Mao, Dong; She, Xiaoyang; Du, Bobo; Yang, Dexing; Zhang, Wending; Song, Kun; Cui, Xiaoqi; Jiang, Biqiang; Peng, Tao; Zhao, Jianlin

    2016-03-01

    Few-layer transition-metal dichalcogenide WSe2/MoSe2 nanosheets are fabricated by a liquid exfoliation technique using sodium deoxycholate bile salt as surfactant, and their nonlinear optical properties are investigated based on a balanced twin-detector measurement scheme. It is demonstrated that both types of nanosheets exhibit nonlinear saturable absorption properties at the wavelength of 1.55 μm. By depositing the nanosheets on side polished fiber (SPF) or mixing the nanosheets with polyvinyl alcohol (PVA) solution, SPF-WSe2 saturable absorber (SA), SPF-MoSe2 SA, PVA-WSe2 SA, and PVA-MoSe2 SA are successfully fabricated and further tested in erbium-doped fiber lasers. The SPF-based SA is capable of operating at the high pump regime without damage, and a train of 3252.65 MHz harmonically mode-locked pulses are obtained based on the SPF-WSe2 SA. Soliton mode locking operations are also achieved in the fiber laser separately with other three types of SAs, confirming that the WSe2 and MoSe2 nanosheets could act as cost-effective high-power SAs for ultrafast optics.

  2. Concentration quenching of praseodymium ions Pr(3+) in BaGd2(MoO4)4 crystals.

    PubMed

    Guan, Ying; Tsuboi, Taiju; Huang, Yanlin; Huang, Wei

    2014-03-01

    The concentration effect on the photoluminescence (PL) of the praseodymium Pr(3+) ion is studied at 298-12 K for barium gadolinium molybdate (BaGd2(MoO4)4, called BGM) crystals with a wide Pr(3+) concentration range of 0.05-25.0 mol%. Three types of concentration dependences are observed for the emissions although all types show PL quenching at high concentrations. The first type (Type A) has the maximum PL intensity at about 10 mol% with a non-zero intensity at high concentrations, which is observed for the (3)P0 emissions except for emission at 621 nm. The second and third types (Type B-1 and B-2) have the maximum at about 1 mol% with a finite residual intensity and nearly zero intensity at high concentrations, respectively, which are observed for the 621 nm emission and all the (1)D2 emissions. It is suggested that the energy migration mechanism is responsible for Type A, while the non-resonant cross-relaxation is responsible for Type B-1 and the resonant cross-relaxation for Type B-2. PMID:24429706

  3. Erbium-doped fiber laser passively mode locked with few-layer WSe2/MoSe2 nanosheets

    PubMed Central

    Mao, Dong; She, Xiaoyang; Du, Bobo; Yang, Dexing; Zhang, Wending; Song, Kun; Cui, Xiaoqi; Jiang, Biqiang; Peng, Tao; Zhao, Jianlin

    2016-01-01

    Few-layer transition-metal dichalcogenide WSe2/MoSe2 nanosheets are fabricated by a liquid exfoliation technique using sodium deoxycholate bile salt as surfactant, and their nonlinear optical properties are investigated based on a balanced twin-detector measurement scheme. It is demonstrated that both types of nanosheets exhibit nonlinear saturable absorption properties at the wavelength of 1.55 μm. By depositing the nanosheets on side polished fiber (SPF) or mixing the nanosheets with polyvinyl alcohol (PVA) solution, SPF-WSe2 saturable absorber (SA), SPF-MoSe2 SA, PVA-WSe2 SA, and PVA-MoSe2 SA are successfully fabricated and further tested in erbium-doped fiber lasers. The SPF-based SA is capable of operating at the high pump regime without damage, and a train of 3252.65 MHz harmonically mode-locked pulses are obtained based on the SPF-WSe2 SA. Soliton mode locking operations are also achieved in the fiber laser separately with other three types of SAs, confirming that the WSe2 and MoSe2 nanosheets could act as cost-effective high-power SAs for ultrafast optics. PMID:27010509

  4. Precipitation of an intermetallic phase with Pt{sub 2}Mo-type structure in alloy 625

    SciTech Connect

    Sundararaman, M.; Kumar, L.; Prasad, G.E.; Mukhopadhyay, P.; Banerjee, S.

    1999-01-01

    The microstructure of Alloy 625, which has undergone prolonged ({approximately}70,000 hours) service at temperatures close to but less than 600 C, has been characterized by transmission electron microscopy. The precipitation of an intermetallic phase Ni{sub 2}(Cr, Mo) with Pt{sub 2}Mo-type structure has been observed in addition to that of the {gamma}{double_prime} phase. Six variants of Ni{sub 2} (Cr, Mo) precipitates have been found to occur in the austenite grains. These particles exhibit a snowflake-like morphology and are uniformly distributed in the matrix. They have been found to dissolve when the alloy is subjected to short heat treatments at 700 C. The occurrence of the Ni{sub 2}(Cr, Mo) phase has been discussed by taking the alloy chemistry into consideration. Apart from the intermetallic phases, the precipitation of a M{sub 6}C-type carbide phase within the matrix and the formation of near continuous films, comprising discrete M{sub 6}C/M{sub 23}C{sub 6} carbide particles, at the austenite grain boundaries have been noticed in the alloy after prolonged service.

  5. Erbium-doped fiber laser passively mode locked with few-layer WSe2/MoSe2 nanosheets.

    PubMed

    Mao, Dong; She, Xiaoyang; Du, Bobo; Yang, Dexing; Zhang, Wending; Song, Kun; Cui, Xiaoqi; Jiang, Biqiang; Peng, Tao; Zhao, Jianlin

    2016-01-01

    Few-layer transition-metal dichalcogenide WSe2/MoSe2 nanosheets are fabricated by a liquid exfoliation technique using sodium deoxycholate bile salt as surfactant, and their nonlinear optical properties are investigated based on a balanced twin-detector measurement scheme. It is demonstrated that both types of nanosheets exhibit nonlinear saturable absorption properties at the wavelength of 1.55 μm. By depositing the nanosheets on side polished fiber (SPF) or mixing the nanosheets with polyvinyl alcohol (PVA) solution, SPF-WSe2 saturable absorber (SA), SPF-MoSe2 SA, PVA-WSe2 SA, and PVA-MoSe2 SA are successfully fabricated and further tested in erbium-doped fiber lasers. The SPF-based SA is capable of operating at the high pump regime without damage, and a train of 3252.65 MHz harmonically mode-locked pulses are obtained based on the SPF-WSe2 SA. Soliton mode locking operations are also achieved in the fiber laser separately with other three types of SAs, confirming that the WSe2 and MoSe2 nanosheets could act as cost-effective high-power SAs for ultrafast optics. PMID:27010509

  6. Electroluminescence and Photocurrent Generation from Atomically Sharp WSe2/MoS2 Heterojunction p–n Diodes

    PubMed Central

    2015-01-01

    The p–n diodes represent the most fundamental device building blocks for diverse optoelectronic functions, but are difficult to achieve in atomically thin transition metal dichalcogenides (TMDs) due to the challenges in selectively doping them into p- or n-type semiconductors. Here, we demonstrate that an atomically thin and sharp heterojunction p–n diode can be created by vertically stacking p-type monolayer tungsten diselenide (WSe2) and n-type few-layer molybdenum disulfide (MoS2). Electrical measurements of the vertically staked WSe2/MoS2 heterojunctions reveal excellent current rectification behavior with an ideality factor of 1.2. Photocurrent mapping shows rapid photoresponse over the entire overlapping region with a highest external quantum efficiency up to 12%. Electroluminescence studies show prominent band edge excitonic emission and strikingly enhanced hot-electron luminescence. A systematic investigation shows distinct layer-number dependent emission characteristics and reveals important insight about the origin of hot-electron luminescence and the nature of electron–orbital interaction in TMDs. We believe that these atomically thin heterojunction p–n diodes represent an interesting system for probing the fundamental electro-optical properties in TMDs and can open up a new pathway to novel optoelectronic devices such as atomically thin photodetectors, photovoltaics, as well as spin- and valley-polarized light emitting diodes, on-chip lasers. PMID:25157588

  7. Structures of exfoliated single layers of WS2, MoS2, and MoSe2 in aqueous suspension

    NASA Astrophysics Data System (ADS)

    Gordon, R. A.; Yang, D.; Crozier, E. D.; Jiang, D. T.; Frindt, R. F.

    2002-03-01

    Single layers of the transition-metal dichalcogenides WS2, MoS2, and MoSe2 were formed as aqueous suspensions by lithium intercalation and exfoliation of crystalline powders and examined by x-ray diffraction and x-ray absorption fine structure (XAFS) spectroscopy. The two-dimensional characteristics of these systems were readily apparent through the absence of any (hkl) peaks (l≠0) and in the strong asymmetry of the (hk0) peaks in the diffraction patterns. Indexing the diffraction patterns with rectangular unit cells revealed the diselenide as the most distorted from the hexagonal structures of the parent materials, with the Mo atoms forming a ``zigzag'' structure which is also corrugated perpendicular to the layers. Mo K-edge and W L3-edge XAFS analysis using WTe2-related structural models enabled the determination of the short, intermediate, and long metal-metal near-neighbor distances with the shortest metal-metal distances contracted approximately 0.4 Å compared to parent reference materials. Shifts in the Mo K-absorption-edge energy in MoSe2 correlated with changing Se-Se interactions. Combining the XAFS and diffraction results enabled an estimation of the layer puckering and atomic positions in three-dimensional models of the unit cells. Selenium K-edge XAFS also identified two selenium-oxygen scattering paths from water or OH- ions coordinating the layers of exfoliated MoSe2.

  8. Electronic structural Moiré pattern effects on MoS2/MoSe2 2D heterostructures.

    PubMed

    Kang, Jun; Li, Jingbo; Li, Shu-Shen; Xia, Jian-Bai; Wang, Lin-Wang

    2013-01-01

    The structural and electronic properties of MoS2/MoSe2 bilayers are calculated using first-principles methods. It is found that the interlayer van der Waals interaction is not strong enough to form a lattice-matched coherent heterostructure. Instead, a nanometer-scale Moiré pattern structure will be formed. By analyzing the electronic structures of different stacking configurations, we predict that the valence-band maximum (VBM) state will come from the Γ point due to interlayer electronic coupling. This is confirmed by a direct calculation of a Moiré pattern supercell containing 6630 atoms using the linear scaling three-dimensional fragment method. The VBM state is found to be strongly localized, while the conduction band minimum (CBM) state is only weakly localized, and it comes from the MoS2 layer at the K point. We predict such wave function localization can be a general feature for many two-dimensional (2D) van der Waals heterostructures and can have major impacts on the carrier mobility and other electronic and optical properties. PMID:24079953

  9. Electroluminescence and photocurrent generation from atomically sharp WSe2/MoS2 heterojunction p-n diodes.

    PubMed

    Cheng, Rui; Li, Dehui; Zhou, Hailong; Wang, Chen; Yin, Anxiang; Jiang, Shan; Liu, Yuan; Chen, Yu; Huang, Yu; Duan, Xiangfeng

    2014-10-01

    The p-n diodes represent the most fundamental device building blocks for diverse optoelectronic functions, but are difficult to achieve in atomically thin transition metal dichalcogenides (TMDs) due to the challenges in selectively doping them into p- or n-type semiconductors. Here, we demonstrate that an atomically thin and sharp heterojunction p-n diode can be created by vertically stacking p-type monolayer tungsten diselenide (WSe2) and n-type few-layer molybdenum disulfide (MoS2). Electrical measurements of the vertically staked WSe2/MoS2 heterojunctions reveal excellent current rectification behavior with an ideality factor of 1.2. Photocurrent mapping shows rapid photoresponse over the entire overlapping region with a highest external quantum efficiency up to 12%. Electroluminescence studies show prominent band edge excitonic emission and strikingly enhanced hot-electron luminescence. A systematic investigation shows distinct layer-number dependent emission characteristics and reveals important insight about the origin of hot-electron luminescence and the nature of electron-orbital interaction in TMDs. We believe that these atomically thin heterojunction p-n diodes represent an interesting system for probing the fundamental electro-optical properties in TMDs and can open up a new pathway to novel optoelectronic devices such as atomically thin photodetectors, photovoltaics, as well as spin- and valley-polarized light emitting diodes, on-chip lasers. PMID:25157588

  10. Room temperature synthesis of K2Mo3O10x3H2O nanowires in minutes.

    PubMed

    Gong, Weiwei; Xue, Jiongwei; Zhang, Kai; Wu, Zhan; Wei, Dapeng; Chen, Qing; Pan, Huayong; Xu, Shengyong

    2009-05-27

    Polyoxometalates have been widely used in the fields of catalysis, analytical chemistry, biochemistry, medicine and synthesis of novel organic-inorganic materials. It is difficult to synthesize pure polymolybdate products from a solution because several kinds of molybdenum-based anions may coexist. As a result, varied acidification methods are commonly used for solution synthesis of polymolybdates. In this paper we report an approach for the synthesis of [001]-oriented K(2)Mo(3)O(10)x3H(2)O nanowires from an aqueous solution of (NH(4))(6)Mo(7)O(24)x4H(2)O and KCl at low temperatures. The reaction occurs even at temperatures as low as 0 degrees C, and at 30-90 degrees C the whole procedure needs only a few minutes. Without any additional acidification treatments, the pH value of the solution is maintained in a narrow range of +/- 0.1 between 4.9 and 5.5 during the whole synthesis procedure. The starting pH depends on the reaction temperature. Crystalline structure and purity of the final products have been characterized with x-ray diffraction, electron diffraction and dehydration measurements. This simple and rapid method provides a unique case for studying the growth mechanism of polymolybdate nanostructures, and has a promising potential in the mass production of low-cost, pure-phase polymolybdates for a variety of applications. PMID:19423934

  11. Microstructure investigation of 13Cr-2Mo ODS steel components obtained by high voltage electric discharge compaction technique

    DOE PAGESBeta

    Bogachev, Igor; Yudin, Artem; Grigoryev, Evgeniy; Chernov, Ivan; Staltsov, Maxim; Khasanov, Oleg; Olevsky, Eugene

    2015-11-02

    Refractory oxide dispersion strengthened 13Cr-2Mo steel powder was successfully consolidated to near theoretical density using high voltage electric discharge compaction. Cylindrical samples with relative density from 90% to 97% and dimensions of 10 mm in diameter and 10–15 mm in height were obtained. Consolidation conditions such as pressure and voltage were varied in some ranges to determine the optimal compaction regime. Three different concentrations of yttria were used to identify its effect on the properties of the samples. It is shown that the utilized ultra-rapid consolidation process in combination with high transmitted energy allows obtaining high density compacts, retaining themore » initial structure with minimal grain growth. The experimental results indicate some heterogeneity of the structure which may occur in the external layers of the tested samples due to various thermal and electromagnetic in-processing effects. As a result, the choice of the optimal parameters of the consolidation enables obtaining samples of acceptable quality.« less

  12. Blister formation on 13Cr2MoNbVB ferritic-martensitic steel exposed to hydrogen plasma

    NASA Astrophysics Data System (ADS)

    Nikitin, A. V.; Tolstolutskaya, G. D.; Ruzhytskyi, V. V.; Voyevodin, V. N.; Kopanets, I. E.; Karpov, S. A.; Vasilenko, R. L.; Garner, F. A.

    2016-09-01

    The influence of pre-irradiation specimen deformation level on surface blister formation and sub-surface cracking of dual-phase 13Cr2MoNbVB ferritic-martensitic steel was studied using glow discharge hydrogen plasma with ion energy of 1 keV to fluences of 2 × 1025 H/m2. Protium was used for most studies, but deuterium was used for measuring the depth dependence of hydrogen diffusion. Formation of blisters was observed in the temperature range 230-340 K. It was found that pre-irradiation deformation caused changes in the threshold fluences of blister formation and also in blister size distribution. Subsurface cracks located on grain boundaries far beyond the implantation zone were formed concurrently with blisters, arising from hydrogen diffusion and trapping at defects. It was observed that cracks as long as 1 mm in length were formed in 95% deformed steel at depths up to 500 μm from surface.

  13. Microwave Dielectric Properties of Temperature-Stable BaLn2(MoO4)4-TiO2 (Ln = Ce, Nd, and Sm) Ceramics

    NASA Astrophysics Data System (ADS)

    Li, Wen-Bo; Xi, Hai-Hong; Zhou, Di

    2015-11-01

    A series of temperature-stable microwave dielectric ceramics (1 - x)Ba Ln2(MoO4)4- xTiO2 (Ln = Ce, Nd, and Sm; 0.4 ≤ x ≤0.55) were prepared by solid-state reaction. Sintering behavior, phase composition, microstructure, and microwave dielectric properties were investigated. X-ray powder diffraction and scanning electron microscopy revealed that the main phases of the BaLn2(MoO4)4-TiO2 ceramics were the monoclinic BaLn2(MoO4)4 phase and the rutile TiO2 phase. Study of the materials' microwave dielectric properties revealed that the permittivity ( ɛ r) and the temperature coefficient of the resonant frequency ( τ f) increased gradually with increasing x value whereas quality factors ( Q × f) decreased. For BaLn2(MoO4)4-TiO2 (Ln = Ce and Nd), τ f values could be adjusted to near zero, relative permittivity ( ɛ r) was 13.2-14.3, and Q × f values were between 11,950 and 45,720 GHz (at 9.11-9.83 GHz) when x = 0.45 to 0.55. For BaSm2(MoO4)4-TiO2, excellent microwave dielectric properties were obtained when x = 0.4 to 0.5, τ f values could be adjusted to near zero, ɛ r was 13.1-13.9, and Q × f values were between 25,520 and 63,130 GHz (at 9.31-10.11 GHz).

  14. Theoretical study of hydration in Y{sub 2}Mo{sub 3}O{sub 12}: Effects on structure and negative thermal expansion

    SciTech Connect

    Wu, Ming-Yi; Wang, Lei; Jia, Yu; Sun, Qiang; Guo, Zheng-Xiao

    2015-02-15

    We report ab-initio calculations of water absorption in Y{sub 2}Mo{sub 3}O{sub 12}. The absorption geometry of H{sub 2}O in Y{sub 2}Mo{sub 3}O{sub 12} and the binding property between H{sub 2}O and Y{sub 2}Mo{sub 3}O{sub 12} have been first identified. Our calculated results show that water is chemisorbed in Y{sub 2}Mo{sub 3}O{sub 12} with O of the water binding to the Y{sup 3+} cation, which is further strengthened by hydrogen bonding between each of the hydrogen atoms of H{sub 2}O and the bridge O in Y{sub 2}Mo{sub 3}O{sub 12}, shared by polyhedrons YO{sub 6} and MoO{sub 4}. The absorption of water leads to a reduced angle of Y-O-Mo and shortened Y-Mo distance, and consequently volume contraction of the material, almost linearly with the increasing number of water molecules per unit cell, up to eight in total. In addition, our phonon calculation show that the transverse vibration of Y-O-Mo is restricted due to water absorption, which in turn hinders the NTE, as it is mainly originated from this vibrational mode. Our results clarify further the fundamental mechanisms of the large volume shrinkage and the lost NTE of the framework oxide due to water absorption.

  15. ARF6-dependent regulation of P2Y receptor traffic and function in human platelets.

    PubMed

    Kanamarlapudi, Venkateswarlu; Owens, Sian E; Saha, Keya; Pope, Robert J; Mundell, Stuart J

    2012-01-01

    Adenosine diphosphate (ADP) is a critical regulator of platelet activation, mediating its actions through two G protein-coupled receptors, the P2Y(1) and P2Y(12) purinoceptors. Recently, we demonstrated that P2Y(1) and P2Y(12) purinoceptor activities are rapidly and reversibly modulated in human platelets, revealing that the underlying mechanism requires receptor internalization and subsequent trafficking as an essential part of this process. In this study we investigated the role of the small GTP-binding protein ADP ribosylation factor 6 (ARF6) in the internalization and function of P2Y(1) and P2Y(12) purinoceptors in human platelets. ARF6 has been implicated in the internalization of a number of GPCRs, although its precise molecular mechanism in this process remains unclear. In this study we show that activation of either P2Y(1) or P2Y(12) purinoceptors can stimulate ARF6 activity. Further blockade of ARF6 function either in cell lines or human platelets blocks P2Y purinoceptor internalization. This blockade of receptor internalization attenuates receptor resensitization. Furthermore, we demonstrate that Nm23-H1, a nucleoside diphosphate (NDP) kinase regulated by ARF6 which facilitates dynamin-dependent fission of coated vesicles during endocytosis, is also required for P2Y purinoceptor internalization. These data describe a novel function of ARF6 in the internalization of P2Y purinoceptors and demonstrate the integral importance of this small GTPase upon platelet ADP receptor function. PMID:22916275

  16. ARF6-Dependent Regulation of P2Y Receptor Traffic and Function in Human Platelets

    PubMed Central

    Kanamarlapudi, Venkateswarlu; Owens, Sian E.; Saha, Keya; Pope, Robert J.; Mundell, Stuart J.

    2012-01-01

    Adenosine diphosphate (ADP) is a critical regulator of platelet activation, mediating its actions through two G protein-coupled receptors, the P2Y1 and P2Y12 purinoceptors. Recently, we demonstrated that P2Y1 and P2Y12 purinoceptor activities are rapidly and reversibly modulated in human platelets, revealing that the underlying mechanism requires receptor internalization and subsequent trafficking as an essential part of this process. In this study we investigated the role of the small GTP-binding protein ADP ribosylation factor 6 (ARF6) in the internalization and function of P2Y1 and P2Y12 purinoceptors in human platelets. ARF6 has been implicated in the internalization of a number of GPCRs, although its precise molecular mechanism in this process remains unclear. In this study we show that activation of either P2Y1 or P2Y12 purinoceptors can stimulate ARF6 activity. Further blockade of ARF6 function either in cell lines or human platelets blocks P2Y purinoceptor internalization. This blockade of receptor internalization attenuates receptor resensitization. Furthermore, we demonstrate that Nm23-H1, a nucleoside diphosphate (NDP) kinase regulated by ARF6 which facilitates dynamin-dependent fission of coated vesicles during endocytosis, is also required for P2Y purinoceptor internalization. These data describe a novel function of ARF6 in the internalization of P2Y purinoceptors and demonstrate the integral importance of this small GTPase upon platelet ADP receptor function. PMID:22916275

  17. Study of the dynamics of the MoO2-Mo2C system for catalytic partial oxidation reactions

    NASA Astrophysics Data System (ADS)

    Cuba Torres, Christian Martin

    On a global scale, the energy demand is largely supplied by the combustion of non-renewable fossil fuels. However, their rapid depletion coupled with environmental and sustainability concerns are the main drivers to seek for alternative energetic strategies. To this end, the sustainable generation of hydrogen from renewable resources such as biodiesel would represent an attractive alternative solution to fossil fuels. Furthermore, hydrogen's lower environmental impact and greater independence from foreign control make it a strong contender for solving this global problem. Among a wide variety of methods for hydrogen production, the catalytic partial oxidation offers numerous advantages for compact and mobile fuel processing systems. For this reaction, the present work explores the versatility of the Mo--O--C catalytic system under different synthesis methods and reforming conditions using methyl oleate as a surrogate biodiesel. MoO2 exhibits good catalytic activity and exhibits high coke-resistance even under reforming conditions where long-chain oxygenated compounds are prone to form coke. Moreover, the lattice oxygen present in MoO2 promotes the Mars-Van Krevelen mechanism. Also, it is introduced a novel beta-Mo2C synthesis by the in-situ formation method that does not utilize external H2 inputs. Herein, the MoO 2/Mo2C system maintains high catalytic activity for partial oxidation while the lattice oxygen serves as a carbon buffer for preventing coke formation. This unique feature allows for longer operation reforming times despite slightly lower catalytic activity compared to the catalysts prepared by the traditional temperature-programmed reaction method. Moreover, it is demonstrated by a pulse reaction technique that during the phase transformation of MoO2 to beta-Mo2C, the formation of Mo metal as an intermediate is not responsible for the sintering of the material wrongly assumed by the temperature-programmed method.

  18. Novel Bi2MoO6/TiO2 heterostructure microspheres for degradation of benzene series compound under visible light irradiation.

    PubMed

    Li, Jinliang; Liu, Xinjuan; Sun, Zhuo; Pan, Likun

    2016-02-01

    Novel Bi2MoO6/TiO2 heterostructure microspheres were successfully synthesized via a facile solvothermal method. Their morphology, structure and photocatalytic performance in the degradation of phenol and nitrobenzene were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, electrochemical impedance spectra, UV-vis absorption spectroscopy and total organic carbon analyser, respectively. The results show that the Bi2MoO6/TiO2 heterostructures exhibit excellent photocatalytic performance with maximum phenol and nitrobenzene degradation rates of 96% and 94% and corresponding mineralization rates of 66% and 61% in 300min under visible light irradiation, respectively. The improved photocatalytic performance is mainly ascribed to the reduced electron-hole pair recombination with the introduction of TiO2. PMID:26520821

  19. [Study on far-infrared reflectivity spectra of microwave dielectric ceramic (RbBi)1/2MoO4].

    PubMed

    Wang, Qiu-Ping; Liu, Han-Chen

    2012-09-01

    The (RbBi)1/2 MoO4 ceramic was prepared via solid state reaction method. The room temperature far-infrared reflectivity spectra were measured and 15 vibration modes were observed. Kramers-Kronig (K-K) relationship was employed to fit infrared spectra. The optical frequency permittivity epsilon infinity is equal to 2. 17 for the dielectric materials, and the extrapolated value to microwave frequency (at about 9 GHz) is 20.56 and it is slightly smaller than the actual measured value -21.4. The calculated value of quality factor (Q x f) is 11 790 GHz, which is higher than the actual measured value -6 200 GHz, and it can be deduced that the quality factor of the (RbBi)1/2 MoO4 ceramic material has large room for improvement. PMID:23240401

  20. Cube-like Cu{sub 2}MoS{sub 4} photocatalysts for visible light-driven degradation of methyl orange

    SciTech Connect

    Zhang, Ke; Chen, Wenxing; Chen, Haiping; Gong, Zhiyu; Chang, Shuo; Ye, Fei; Wang, Tianxing; Chu, Wangsheng; Zou, Chongwen; Song, Li; Wang, Yu; Li, Jiong

    2015-07-15

    Cube-like Cu{sub 2}MoS{sub 4} nanoparticles with low-index facets and high crystallinity were fabricated via a hydrothermal method. The as-obtained nanocubes with an average size of 40-60 nm are composed of stacking-Cu{sub 2}MoS{sub 4} layers separated by a weak Van der Waals gap of 0.5 nm. A strong absorption at visible light region is observed in the nanocube aqueous solution, indicating its optical-band gap of 1.78 eV. The photocatalytic measurements reveal that the nanocubes can thoroughly induce the degradation of methyl orange under visible light irradiation with good structural stability. Our finding may provide a way in design and fabrication of transition metal dichalcogenide nanostructures for practical applications.

  1. Novel Na2Mo4O13/α-MoO3 hybrid material as highly efficient CWAO catalyst for dye degradation at ambient conditions

    NASA Astrophysics Data System (ADS)

    Zhang, Zhang; Yang, Ruoyan; Gao, Yanshan; Zhao, Yufei; Wang, Junyang; Huang, Liang; Guo, Jiang; Zhou, Tuantuan; Lu, Peng; Guo, Zhanhu; Wang, Qiang

    2014-10-01

    We report a novel hybrid material Na2Mo4O13/α-MoO3 as highly efficient catalytic wet air oxidation (CWAO) catalyst, which showed the highest ever activity at room temperature and atmosphere pressure for the degradation of cationic red GTL. SEM and TEM analyses indicated that this hybrid catalyst has bamboo-shaped nanofiber morphology. In view of practical applications, the influence of some key parameters including operation temperature, catalyst calcination temperature, and the volume of dye wastewater have been optimized. The mechanism for the superior catalytic performance was investigated. XRD, XPS, and ESR suggested the Na2Mo4O13/α-MoO3 hybrid catalyst possesses more O2- ions in the oxygen deficient regions than neat α-MoO3, promoting the formation of active .OH radicals and resulting in a higher activity. Considering the facile preparation and its superior activity, this novel catalyst is promising for practical dye wastewater treatment.

  2. Aboveground test of an advanced Li2MoO4 scintillating bolometer to search for neutrinoless double beta decay of 100Mo

    NASA Astrophysics Data System (ADS)

    Bekker, T. B.; Coron, N.; Danevich, F. A.; Degoda, V. Ya.; Giuliani, A.; Grigorieva, V. D.; Ivannikova, N. V.; Mancuso, M.; de Marcillac, P.; Moroz, I. M.; Nones, C.; Olivieri, E.; Pessina, G.; Poda, D. V.; Shlegel, V. N.; Tretyak, V. I.; Velazquez, M.

    2016-01-01

    Large lithium molybdate (Li2MoO4) crystal boules were produced by using the low thermal gradient Czochralski growth technique from deeply purified molybdenum. A small sample from one of the boules was preliminary characterized in terms of X-ray-induced and thermally-excited luminescence. A large cylindrical crystalline element (with a size of ⊘40 × 40 mm) was used to fabricate a scintillating bolometer, which was operated aboveground at ˜15 mK by using a pulse-tube cryostat housing a high-power dilution refrigerator. The excellent detector performance in terms of energy resolution and α background suppression along with preliminary positive indications on the radiopurity of this material show the potentiality of Li2MoO4 scintillating bolometers for low-counting experiment to search for neutrinoless double beta decay of 100Mo.

  3. Magnetic order and electronic properties of Li2Mn2(MoO4)3 material for lithium-ion batteries: ESR and magnetic susceptibility studies

    NASA Astrophysics Data System (ADS)

    Suleimanov, N. M.; Prabaharan, S. R. S.; Khantimerov, S. M.; Nizamov, F. A.; Michael, M. S.; Drulis, H.; Wisniewski, P.

    2016-08-01

    We describe the application of electron spin resonance (ESR) and magnetic susceptibility methods to study the magnetic properties and valence state of transition metal ions in Li2Mn2(MoO4)3 polyanion compound previously studied for its cathode-active properties in lithium containing batteries. ESR measurements of Li2Mn2(MoO4)3 have shown the presence of Mn2+ ions in the octahedral environment of oxygen ions. It is found that the part of manganese ions occupy the anti-site positions in lithium sublattice. The absence of the ESR signal from molybdenum ions indicates that they are non-magnetic and adopt the 6+ valence state. Considerable overlapping between 3d orbitals of transition metal and 2p oxygen orbitals has been experimentally established. This leads to the indirect exchange interaction and antiferromagnetic ordering of manganese ions at 1.4 K.

  4. Caged Agonist of P2Y1 and P2Y12 Receptors for Light-Directed Facilitation of Platelet Aggregation

    PubMed Central

    Gao, Zhan-Guo; Hechler, Béatrice; Besada, Pedro; Gachet, Christian; Jacobson, Kenneth A.

    2008-01-01

    We have prepared a caged form (MRS2703) of a potent dual agonist of the P2Y1 and P2Y12 nucleotide receptors, 2-MeSADP, by blocking the β-phosphate group with a 1-(3,4-dimethyloxyphenyl)eth-1-yl phosphoester. Although MRS2703 is itself inactive at human P2Y1 and P2Y12 receptors expressed heterologously in 1321N1 astrocytoma cells or in washed human platelets, this derivative readily regenerates the parent agonist upon mild irradiation with long-wave UV light (360 nm). The functional effect of the regenerated agonist was demonstrated by a rise in intracellular calcium mediated by either P2Y1 or P2Y12 receptors in transfected cells. Washed human platelets exposed to a solution of MRS2703 were induced to aggregate upon UV irradiation. At 1.0 μM MRS2703, full aggregation was achieved within one minute of irradiation. Thus, this caged nucleotide promises to be a useful probe for potent P2Y receptor activation with light-directed spatial and temporal control. PMID:18199424

  5. Caged agonist of P2Y1 and P2Y12 receptors for light-directed facilitation of platelet aggregation.

    PubMed

    Gao, Zhan-Guo; Hechler, Béatrice; Besada, Pedro; Gachet, Christian; Jacobson, Kenneth A

    2008-03-15

    We have prepared a caged form (MRS2703) of a potent dual agonist of the P2Y(1) and P2Y(12) nucleotide receptors, 2-MeSADP, by blocking the beta-phosphate group with a 1-(3,4-dimethyloxyphenyl)eth-1-yl phosphoester. Although MRS2703 is itself inactive at human P2Y(1) and P2Y(12) receptors expressed heterologously in 1321N1 astrocytoma cells or in washed human platelets, this derivative readily regenerates the parent agonist upon mild irradiation with long-wave UV light (360 nm). The functional effect of the regenerated agonist was demonstrated by a rise in intracellular calcium mediated by either P2Y(1) or P2Y(12) receptors in transfected cells. Washed human platelets exposed to a solution of MRS2703 were induced to aggregate upon UV irradiation. At 1.0 microM MRS2703, full aggregation was achieved within 1 min of irradiation. Thus, this caged nucleotide promises to be a useful probe for potent P2Y receptor activation with light-directed spatial and temporal control. PMID:18199424

  6. Elastic-plastic deformations of a beam with the SD-effect

    SciTech Connect

    Pavilaynen, Galina V.

    2015-03-10

    The results for the bending of a cantilever beam with the SD-effect under a concentrated load are discussed. To solve this problem, the standard Bernoulli-Euler hypotheses for beams and the Ilyushin model of perfect plasticity are used. The problem is solved analytically for structural steel A40X. The SD-effect for elastic-plastic deformations is studied. The solutions for beam made of isotropic material and material with the SD-effect are compared.

  7. SD-pair shell model study for {sup 126}Xe and {sup 128}Ba

    SciTech Connect

    Meng Xiangfei; Luo Yanan; Wang, Fu-rong; Pan Feng; Draayer, Jerry P.

    2008-04-15

    The SD-pair shell model is employed to study {sup 126}Xe and {sup 128}Ba. The results show that the spectra and electromagnetic transition strengths can be nicely described in terms of a three-parameter Hamiltonian. In our previous paper, we got a conclusion that the SD-pair approximation improves with the number of SD pairs N. This work shows that this conclusion can be extrapolated to the case with N=5.

  8. Epitaxial Growth of Lattice-Mismatched Core-Shell TiO2 @MoS2 for Enhanced Lithium-Ion Storage.

    PubMed

    Dai, Rui; Zhang, Anqi; Pan, Zhichang; Al-Enizi, Abdullah M; Elzatahry, Ahmed A; Hu, Linfeng; Zheng, Gengfeng

    2016-05-01

    Core-shell structured nanohybrids are currently of significant interest due to their synergetic properties and enhanced performances. However, the restriction of lattice mismatch remains a severe obstacle for heterogrowth of various core-shells with two distinct crystal structures. Herein, a controlled synthesis of lattice-mismatched core-shell TiO2 @MoS2 nano-onion heterostructures is successfully developed, using unilamellar Ti0.87 O2 nanosheets as the starting material and the subsequent epitaxial growth of MoS2 on TiO2 . The formation of these core-shell nano-onions is attributed to an amorphous layer-induced heterogrowth mechanism. The number of MoS2 layers can be well tuned from few to over ten layers, enabling layer-dependent synergistic effects. The core-shell TiO2 @MoS2 nano-onion heterostructures exhibit significantly enhanced energy storage performance as lithium-ion battery anodes. The approach has also been extended to other lattice-mismatched systems such as TiO2 @MoSe2 , thus suggesting a new strategy for the growth of well-designed lattice-mismatched core-shell structures. PMID:27062267

  9. Fabrication of TiO2/MoS2@zeolite photocatalyst and its photocatalytic activity for degradation of methyl orange under visible light

    NASA Astrophysics Data System (ADS)

    Zhang, Weiping; Xiao, Xinyan; Zheng, Lili; Wan, Caixia

    2015-12-01

    TiO2/MoS2@zeolite composite photocatalysts with visible-light activity were fabricated via a simple ultrasonic-hydrothermal synthesis method, using TiCl4 as Ti source, MoS2 as a direct sensitizer, glycerol water solution with certain dispersion agent as hydrolytic agent, and zeolite as carrier. The structure, morphology, composition, optical properties, and specific surface area of the as-prepared photocatalysts were characterized by using XRD, FTIR, SEM-EDS, TEM, XPS, UV-vis, PL and BET analyzer, respectively. And the photocatalytic degradation of methyl orange (MO) in aqueous suspension has been employed to evaluate the photocatalytic activity and degradation kinetics of as-prepared photocatalysts with xenon lamp as irradiation source. The results indicate that: (1) TiO2/MoS2@zeolite composite photocatalysts exhibit enhanced photocatalytic activities for methyl orange (MO) degradation compared to Degussa P25; (2) photocatalytic degradation of MO obeys Langmuir-Hinshelwood kinetic model (pseudo-first order reaction), and its degradation rate constant (kapp) (2.304 h-1) is higher than that of Degussa P25 (0.768 h-1); (3) the heterostructure consisted of zeolite, MoS2 and TiO2 nanostructure could provide synergistic effect for degradation of MO due to the efficient electron transfer process and better absorption property of TiO2/MoS2@zeolite composite photocatalyst.

  10. B-site disordering in Ba{sub 3}Ln{sub 2}MoO{sub 9} (Ln=Ho, Er) perovskites: A neutron diffraction study

    SciTech Connect

    Larregola, S.A.; Alonso, J.A.; Garcia Hernandez, M.; Fernandez-Diaz, M.T.; Pedregosa, J.C.

    2009-06-15

    We describe the preparation, structure determination and magnetic properties of two Ba perovskites containing rare-earth cations at the B-sublattice. Ba{sub 3}Ln{sub 2}MoO{sub 9} (Ln=Ho{sup 3+} and Er{sup 3+}) were synthesized by ceramic procedures. Joint X-ray (XRPD) and neutron (NPD) powder diffraction refinements were carried out to analyse the crystal structure. At room temperature, both phases are tetragonal, space group I4/mcm, Z=4. Ln and Mo atoms are found to be distributed at random over the octahedral sites of the perovskites. Magnetic measurements at 0.1 T show that both samples are paramagnetic between 3 and 300 K, following a Curie-Weiss law. M vs. H curves show a region of paramagnetic behaviour and above 2.5 T a magnetic saturated system is observed. Finally, the temperature evolution of the NPD patterns of Ba{sub 3}Ho{sub 2}MoO{sub 9} reveals the absence of long-range magnetic ordering down to 2 K. - Graphical Abstract: Preparation, structure and magnetic properties of Ba{sub 3}Ln{sub 2}MoO{sub 9} (Ln=Ho{sup 3+} and Er{sup 3+}) are descripted. Joint XRPD and NPD refinements confirm a tetragonal I4/mcm structure. Ln and Mo atoms are found to be distributed at random over the octahedral sites of the perovskites.

  11. An X-ray diffraction study of pressure-induced phase transitions in Bi{sub 2}MoO{sub 6}

    SciTech Connect

    Scott, Paul R.; Crow, J.A.; Maczka, M.; Kruger, M.B.

    2012-10-15

    Synchrotron based X-ray diffraction through a diamond anvil cell was used to determine the equations of state and pressure-induced phase transitions in Bi{sub 2}MoO{sub 6}. It was observed that Bi{sub 2}MoO{sub 6} undergoes a phase transformation at {approx}6.8 GPa. The high-pressure phase can be indexed to the orthorhombic structure and the transition is reversible on decompression from {approx}47 GPa. The bulk moduli of the low and high-pressure phases were calculated, while holding K Prime =4, to be: K=51{+-}1 GPa and K=141.5 {+-}0.1 GPa, respectively. - Graphical abstract: The material Bi{sub 2}MoO{sub 6} was placed inside a diamond anvil cell and then studied under high pressure at beamline X17C of the National Synchrotron Light source. X-ray diffraction data was analyzed using the Rietveld method. Highlights: Black-Right-Pointing-Pointer A high-pressure study of bismuth molybdate was performed. Black-Right-Pointing-Pointer Pressure-induced phase transitions were observed. Black-Right-Pointing-Pointer The low pressure phase bulk modulus was calculated to be K=51{+-}1 GPa. Black-Right-Pointing-Pointer The high pressure phase bulk modulus was calculated to be B=141.5{+-}0.1 GPa.

  12. How UV photolysis accelerates the biodegradation and mineralization of sulfadiazine (SD).

    PubMed

    Pan, Shihui; Yan, Ning; Liu, Xinyue; Wang, Wenbing; Zhang, Yongming; Liu, Rui; Rittmann, Bruce E

    2014-11-01

    Sulfadiazine (SD), one of broad-spectrum antibiotics, exhibits limited biodegradation in wastewater treatment due to its chemical structure, which requires initial mono-oxygenation reactions to initiate its biodegradation. Intimately coupling UV photolysis with biodegradation, realized with the internal loop photobiodegradation reactor, accelerated SD biodegradation and mineralization by 35 and 71 %, respectively. The main organic products from photolysis were 2-aminopyrimidine (2-AP), p-aminobenzenesulfonic acid (ABS), and aniline (An), and an SD-photolysis pathway could be identified using C, N, and S balances. Adding An or ABS (but not 2-AP) into the SD solution during biodegradation experiments (no UV photolysis) gave SD removal and mineralization rates similar to intimately coupled photolysis and biodegradation. An SD biodegradation pathway, based on a diverse set of the experimental results, explains how the mineralization of ABS and An (but not 2-AP) provided internal electron carriers that accelerated the initial mono-oxygenation reactions of SD biodegradation. Thus, multiple lines of evidence support that the mechanism by which intimately coupled photolysis and biodegradation accelerated SD removal and mineralization was through producing co-substrates whose oxidation produced electron equivalents that stimulated the initial mono-oxygenation reactions for SD biodegradation. PMID:25199943

  13. The Roles of P2Y2 Purinergic Receptors in Osteoblasts and Mechanotransduction

    PubMed Central

    Xing, Yanghui; Gu, Yan; Bresnahan, James J.; Paul, Emmanuel M.; Donahue, Henry J.; You, Jun

    2014-01-01

    We previously demonstrated, using osteoblastic MC3T3-E1 cells, that P2Y2 purinergic receptors are involved in osteoblast mechanotransduction. In this study, our objective was to further investigate, using a knockout mouse model, the roles of P2Y2 receptors in bone mechanobiology. We first examined bone structure with micro-CT and measured bone mechanical properties with three point bending experiments in both wild type mice and P2Y2 knockout mice. We found that bones from P2Y2 knockout mice have significantly decreased bone volume, bone thickness, bone stiffness and bone ultimate breaking force at 17 week old age. In order to elucidate the mechanisms by which P2Y2 receptors contribute to bone biology, we examined differentiation and mineralization of bone marrow cells from wild type and P2Y2 knockout mice. We found that P2Y2 receptor deficiency reduces the differentiation and mineralization of bone marrow cells. Next, we compared the response of primary osteoblasts, from both wild type and P2Y2 knockout mice, to ATP and mechanical stimulation (oscillatory fluid flow), and found that osteoblasts from wild type mice have a stronger response, in terms of ERK1/2 phosphorylation, to both ATP and fluid flow, relative to P2Y2 knockout mice. However, we did not detect any difference in ATP release in response to fluid flow between wild type and P2Y2 knock out osteoblasts. Our findings suggest that P2Y2 receptors play important roles in bone marrow cell differentiation and mineralization as well as in bone cell mechanotransduction, leading to an osteopenic phenotype in P2Y2 knockout mice. PMID:25268784

  14. Identification of a New Morpholine Scaffold as a P2Y12 Receptor Antagonist.

    PubMed

    Ahn, Young Ha; Lee, Joo-Youn; Park, Hee Dong; Kim, Tae Hun; Park, Min Chul; Choi, Gildon; Kim, Sunghoon

    2016-01-01

    The P2Y12 receptor is critical for platelet activation and is an attractive drug target for the prevention of atherothrombotic events. Despite the proven antithrombotic efficacy of P2Y12 inhibitors, these thienopyridine scaffolds are prodrugs that lack important features of the ideal antithrombotic agent. For this reason, ticagrelor-a new chemical class of P2Y12 receptor antagonist-was developed, but it can cause shortness of breath and various types of bleeding. Moreover, ticagrelor is a cytochrome P450 3A4 substrate/inhibitor and, therefore, caution should be exercised when it is used concomitantly with strong CYP3A4 inducers/inhibitors. There is a need for novel P2Y12 receptor antagonist scaffolds that are reversible and have high efficacy without associated side effects. Here, we describe a novel antagonist containing a morpholine moiety that was identified by screening libraries of commercially available compounds. The molecule, Compound E, acted on P2Y12, but not P2Y1 and P2Y13, and exhibited pharmacological characteristics that were distinct from those of ticagrelor, acting instead on P2Y12 via an allosteric mechanism. These results provide a basis for the development/optimization of a new class of P2Y12 antagonists. PMID:27563870

  15. On the Components of Segregation Distortion in DROSOPHILA MELANOGASTER. II. Deletion Mapping and Dosage Analysis of the SD Locus

    PubMed Central

    Brittnacher, John G.; Ganetzky, Barry

    1983-01-01

    Segregation distorter (SD) chromosomes are preferentially transmitted to offspring from heterozygous SD/SD+ males owing to the induced dysfunction of the SD+-bearing sperm. This phenomenon involves at least two major loci: the Sd locus whose presence is necessary for distortion to occur and the Rsp locus which acts as the site of Sd action. Several additional loci on SD chromosomes enhance distortion.—In a previous study deletions were used to map the Sd locus and to determine some of its properties. We have extended this analysis with the isolation and characterization of 14 new deletions in the Sd region. From our results we conclude (1) SD chromosomes contain a single Sd locus located in region 37D2-6 of the salivary gland chromosome map. Deletion of this locus in any of three SD chromosomes now studied results in complete loss of ability to distort a sensitive chromosome; (2) the reduced male fecundity observed in many homozygous SD or SDi/SDj combinations is due at least in part to the action of the Sd locus. The fecundity of these males can be substantially increased by deletion of one Sd locus. Thus, it is the presence of two doses of Sd rather than the absence of Sd+ that produces the lowered male fecundity in SD homozygotes; (3) Sd behaves as a neomorph, whereas Sd+, if it exists at all, is amorphic with respect to segregation distortion; (4) these results support a model in which the Sd product is made in limiting amounts and the interaction of this product with the Rsp locus causes sperm dysfunction. The Sd product appears to act preferentially at Rsps (sensitive-Responder) but may also act at Rspi (insensitive-Responder). PMID:17246120

  16. Cytokeratin 8 in Association with sdLDL and ELISA Development

    PubMed Central

    Ashmaig, Mohmed

    2015-01-01

    Background: Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide. Cytokeratins (CKs) which may also be expressed in vascular smooth muscle cells (SMCs) are generally considered to be markers for the differentiation of epithelial cells. Small, dense, low-density lipoprotein (sdLDL) particles, also termed LDL-IV, independently predict risk of CVD. Aims: The aims of this study were to develop an analytical method, apart from ultracentrifugation capable of isolating sdLDL in order to study any associated proteins. Materials and Methods: Using modified gradient gel electrophoresis (GGE), de-identified sdLDL-enriched plasma was used to physically elute and isolate sdLDL particles. To validate the finding, additional plasma from 77 normal and 48 higher risk subjects were used to measure sdLDL particles and CK8. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting method were used to identify the characteristics of proteins associated with sdLDL. An enzyme-linked immunosorbent assay (ELISA) method was developed and validated for the measurement of CK8 in plasma. Results: The validation of the CK8 ELISA method showed good analytical performance. The isolated sdLDL particles were verified with nondenaturing GGE with the apolipoprotein B component confirmed by Western immunoblotting. Confirmed by SDS-PAGE and Western immunoblotting, CK8 was associated with sdLDL. Two-tailed statistical analysis showed that CK8 and sdLDL particles were significantly higher in the high-risk CVD group compared to control group (P < 0.01 and P < 0.01, respectively). Conclusion: This study reports a novel association between CK8 and sdLDL in individuals with CVD who have a predominance of sdLDL. PMID:26713292

  17. Quantum phase transitional patterns in the SD-pair shell model

    SciTech Connect

    Luo Yanan; Meng Xiangfei; Zhang Yu; Pan Feng; Draayer, Jerry P.

    2009-07-15

    Patterns of shape-phase transition in the proton-neutron coupled systems are studied within the SD-pair shell model. The results show that some transitional patterns in the SD-pair shell model are similar to the U(5)-SU(3) and U(5)-SO(6) transitions with signatures of the critical point symmetry of the interacting boson model.

  18. 32. DETAIL OF WALL SHOWN IN SD231. BEHIND WALL FRAMING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. DETAIL OF WALL SHOWN IN SD-2-31. BEHIND WALL FRAMING IS SAMPLING ROOM WITH WOOD SAMPLING ELEVATOR. CRUSHED OXIDIZED ORE BIN ON LEFT (SOUTH). - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  19. Regulation of P2Y1 receptor traffic by sorting Nexin 1 is retromer independent.

    PubMed

    Nisar, Shaista; Kelly, Eamonn; Cullen, Pete J; Mundell, Stuart J

    2010-04-01

    The activity and traffic of G-protein coupled receptors (GPCRs) is tightly controlled. Recent work from our laboratory has shown that P2Y(1) and P2Y(12) responsiveness is rapidly and reversibly modulated in human platelets and that the underlying mechanism requires receptor trafficking as an essential part of this process. However, little is known about the molecular mechanisms underlying P2Y receptor traffic. Sorting nexin 1 (SNX1) has been shown to regulate the endosomal sorting of cell surface receptors either to lysosomes where they are downregulated or back to the cell surface. These functions may in part be due to interactions of SNX1 with the mammalian retromer complex. In this study, we investigated the role of SNX1 in P2Y receptor trafficking. We show that P2Y(1) receptors recycle via a slow recycling pathway that is regulated by SNX1, whereas P2Y(12) receptors return to the cell surface via a rapid route that is SNX1 independent. SNX1 inhibition caused a dramatic increase in the rate of P2Y(1) receptor recycling, whereas inhibition of Vps26 and Vps35 known to be present in retromer had no effect, indicating that SNX1 regulation of P2Y(1) receptor recycling is retromer independent. In addition, inhibition of SNX4, 6 and 17 proteins did not affect P2Y(1) receptor recycling. SNX1 has also been implicated in GPCR degradation; however, we provide evidence that P2Y receptor degradation is SNX1 independent. These data describe a novel function of SNX1 in the regulation of P2Y(1) receptor recycling and suggest that SNX1 plays multiple roles in endocytic trafficking of GPCRs. PMID:20070609

  20. HOW TO MAKE A SINGLETON sdB STAR VIA ACCELERATED STELLAR EVOLUTION

    SciTech Connect

    Clausen, Drew; Wade, Richard A. E-mail: wade@astro.psu.edu

    2011-06-01

    Many hot subdwarf B stars (sdBs) are in close binaries, and the favored formation channels for subdwarfs rely on mass transfer in a binary system to strip a core He-burning star of its envelope. However, these channels cannot account for sdBs that have been observed in long-period binaries nor the narrow mass distribution of isolated (or 'singleton') sdBs. We propose a new formation channel involving the merger of a helium white dwarf and a low-mass, hydrogen-burning star, which addresses these issues. Hierarchical triples whose inner binaries merge and form sdBs by this process could explain the observed long-period subdwarf+main-sequence binaries. This process would also naturally explain the observed slow rotational speeds of singleton sdBs. We also briefly discuss the implications of this formation channel for extreme horizontal branch morphology in globular clusters and the UV upturn in elliptical galaxies.

  1. Mineralogic variation in drill holes USW NRG-6, NRG-7/7a, SD-7, SD-9, SD-12, and UZ{number_sign}14: New data from 1996--1997 analyses

    SciTech Connect

    Chipera, S.J.; Vaniman, D.T.; Bish, D.L.; Carey, J.W.

    1997-05-30

    New quantitative X-ray diffraction (QXRD) mineralogic data have been obtained for samples from drill holes NRG-6, NRG-7/7A, SD-7, SD-9, SD- 12, and UZ{number_sign}14. In addition, new QXRD analyses were obtained on samples located in a strategic portion of drill hole USW H-3. These data improve our understanding of the mineral stratigraphy at Yucca Mountain, and they further constrain the 3-D Mineralogic Model of Yucca Mountain. Some of the unexpected findings include the occurrence of the zeolite chabazite in the vitric zone of USW SD-7, broad overlap of vitric and zeolitic horizons (over vertical ranges up to 70 m), and the previously unrecognized importance of the bedded tuft beneath the Calico Hills Formation as a subunit with generally more extensive zeolitization than the Calico Hills Formation in the southern part of the potential repository area. Reassessment of data from drill hole USW H-5 suggests that the zeolitization of this bedded unit occurs in the northwestern part of the repository exploration block as well. Further analyses of the same interval in USW H-3, however, have not permitted the same conclusion to be reached for the southwestern part of the repository block because of the much poorer quality of the cuttings in H-3 compared with those from H-5. X-ray fluorescence (XRF) chemical data for drill holes USW SD-7, 9, and 12 show that the zeolitic horizons provide a >10 million year record of retardation of Sr transport, although the data also show that simplistic models of one-dimensional downward flow in the unsaturated zone (UZ) are inadequate. Complex interstratification of zeolites and glass, with highly variable profiles between drill cores, point to remaining problems in constructing detailed mineral stratigraphies. However, the new data in this report provide important information for constructing bounding models of zeolite stratigraphy for transport calculations.

  2. Microglial P2Y12 receptors regulate microglial activation and surveillance during neuropathic pain.

    PubMed

    Gu, Nan; Eyo, Ukpong B; Murugan, Madhuvika; Peng, Jiyun; Matta, Sanjana; Dong, Hailong; Wu, Long-Jun

    2016-07-01

    Microglial cells are critical in the pathogenesis of neuropathic pain and several microglial receptors have been proposed to mediate this process. Of these receptors, the P2Y12 receptor is a unique purinergic receptor that is exclusively expressed by microglia in the central nervous system (CNS). In this study, we set forth to investigate the role of P2Y12 receptors in microglial electrophysiological and morphological (static and dynamic) activation during spinal nerve transection (SNT)-induced neuropathic pain in mice. First, we found that a genetic deficiency of the P2Y12 receptor (P2Y12(-/-) mice) ameliorated pain hypersensitivities during the initiation phase of neuropathic pain. Next, we characterised both the electrophysiological and morphological properties of microglia in the superficial spinal cord dorsal horn following SNT injury. We show dramatic alterations including a peak at 3days post injury in microglial electrophysiology while high resolution two-photon imaging revealed significant changes of both static and dynamic microglial morphological properties by 7days post injury. Finally, in P2Y12(-/-) mice, these electrophysiological and morphological changes were ameliorated suggesting roles for P2Y12 receptors in SNT-induced microglial activation. Our results therefore indicate that P2Y12 receptors regulate microglial electrophysiological as well as static and dynamic microglial properties after peripheral nerve injury, suggesting that the microglial P2Y12 receptor could be a potential therapeutic target for the treatment of neuropathic pain. PMID:26576724

  3. P2Y Receptors in Synaptic Transmission and Plasticity: Therapeutic Potential in Cognitive Dysfunction

    PubMed Central

    Guzman, Segundo J.; Gerevich, Zoltan

    2016-01-01

    ATP released from neurons and astrocytes during neuronal activity or under pathophysiological circumstances is able to influence information flow in neuronal circuits by activation of ionotropic P2X and metabotropic P2Y receptors and subsequent modulation of cellular excitability, synaptic strength, and plasticity. In the present paper we review cellular and network effects of P2Y receptors in the brain. We show that P2Y receptors inhibit the release of neurotransmitters, modulate voltage- and ligand-gated ion channels, and differentially influence the induction of synaptic plasticity in the prefrontal cortex, hippocampus, and cerebellum. The findings discussed here may explain how P2Y1 receptor activation during brain injury, hypoxia, inflammation, schizophrenia, or Alzheimer's disease leads to an impairment of cognitive processes. Hence, it is suggested that the blockade of P2Y1 receptors may have therapeutic potential against cognitive disturbances in these states. PMID:27069691

  4. Negative thermal expansion correlated with polyhedral movements and distortions in orthorhombic Y{sub 2}Mo{sub 3}O{sub 12}

    SciTech Connect

    Wang, Lei; Wang, Fei; Yuan, Peng-Fei; Sun, Qiang; Liang, Er-Jun; Jia, Yu; Guo, Zheng-Xiao

    2013-07-15

    Graphical abstract: Our work confirms the negative thermal expansion (NTE) behavior of the orthorhombic Y{sub 2}Mo{sub 3}O{sub 12} in this range 0–1000 K. The orthorhombic Y{sub 2}Mo{sub 3}O{sub 12} has an open framework structure where MoO{sub 4} tetrahedra and YO{sub 6} octahedra are connected by oxygen atoms. The previous mechanisms for the NTE behavior of orthorhombic Y{sub 2}Mo{sub 3}O{sub 12} are that the translational mode (see (b)) of the O bridge atoms in Y-O-Mo linkages will cause the linkages to be bent, reducing the space between polyhedra and making the volumetric shrinkage. Furthermore, the internal polyhedral distortions have been reported experimentally. It is necessary to reveal the relationship between NTE and polyhedral movements, distortions. From the vibrational properties, we get that the different vibrational eigenvectors of oxygen atoms relative to Y or Mo atoms can lead internal polyhedra to distort unevenly (see (c)). Herein, an extended 3D model of the connected unit YO{sub 6}-MoO{sub 4} based on the Y-O-Mo linkage is proposed (see (a)). It presents a simultaneous dynamic process, i.e. the YO{sub 6} octahedra and MoO{sub 4} tetrahedra distort unevenly, along with both polyhedra being closer which makes the volumetric contraction. This model is helpful to improve the mechanisms of NTE and may be applied in the whole A{sub 2}M{sub 3}O{sub 12} family. - Highlights: • The NTE properties of Y{sub 2}Mo{sub 3}O{sub 12} are confirmed using a first-principles calculation. • The optical branch with the lowest frequency is most responsible for the NTE. • The relationship between NTE and polyhedral movements, distortions is elucidated. • An extended 3D model of the connected unit YO{sub 6}-MoO{sub 4} is proposed. - Abstract: The internal polyhedral distortions have been reported experimentally in orthorhombic Y{sub 2}Mo{sub 3}O{sub 12} as a negative thermal expansion (NTE) material. To reveal the relationship between NTE and polyhedral

  5. Electrochemical and spectroelectrochemical properties of SnO{sub 2} and SnO{sub 2}/Mo transparent electrodes with high ion-storage capacity

    SciTech Connect

    Krasovec, U.O.; Orel, B.; Hocevar, S.; Musevic, I.

    1997-10-01

    Thin solid SnO{sub 2} and SnO{sub 2}/Mo (10%, 2:1 and 1:1) films with an ion-storage capacity of 20 to 30 mC/cm{sup 2} and weakly expressed cathodic electrochromism were deposited using the dip-coating technique. The films were deposited from peroxo sols prepared by reacting SnCl{sub 2} {center_dot} 2H{sub 2}O and a metallic molybdenum precursor with H{sub 2}O{sub 2}. Thermogravimetric, surface area (BET), x-ray diffraction, and IR spectroscopic measurements of films heat-treated at 500 C revealed a nanocrystalline (grain size {approximately}30 {angstrom}) cassiterite structure with a large surface area ({approximately}60 to 70 m{sup 2}/g). The electrochemical properties of the films were studied in a 1 M LiClO{sub 4}/propylene carbonate electrolyte using cyclic voltammetry (CV) at different scanning rates (0.1 to 200 mV/s). Electrochromic properties, measured in situ with ultraviolet-visible measurements, revealed that the coloring/bleaching changes accompanying insertion/extraction of Li{sup +} ion processes are 10 to 15% for SnO{sub 2}/Mo (1:1) films but decrease to a few percent with decreasing Mo content. Low-scan-rate CV measurements confirmed the presence of two different redox processes: Sn{sup 4+}/Sn{sup 2+} and Mo{sup 6+}/Mo{sup 5+}. This was confirmed from the ex situ IR spectroelectrochemical measurements of films charged/discharged to different extents. IR spectra of films heat-treated at 500 C in a vacuum also showed that SnO{sub 2}/Mo (2:1) films contain Broensted acidic protons. These films, because of their low coloration efficiency (2 to 10 cm{sup 2}/C), are promising counterelectrodes for electrochromic devices with light reflection modulation.

  6. Writing of nonlinear optical Sm{sub 2}(MoO{sub 4}){sub 3} crystal lines at the surface of glass by samarium atom heat processing

    SciTech Connect

    Abe, M.; Benino, Y.; Fujiwara, T.; Komatsu, T.; Sato, R.

    2005-06-15

    Some glasses such as 21.25Sm{sub 2}O{sub 3}.63.75MoO{sub 3}.15B{sub 2}O{sub 3} (mol %) giving the formation of nonlinear optical Sm{sub 2}(MoO{sub 4}){sub 3} crystals through conventional crystallization in an electric furnace and through continuous-wave Nd: yttrium aluminum garnet (YAG) laser (wavelength: 1064 nm) irradiation (samarium atom heat processing) have been developed. It is proposed from x-ray diffraction analyses, micro-Raman-scattering spectra, and second-harmonic generation measurements that the crystal structure of Sm{sub 2}(MoO{sub 4}){sub 3} formed by the crystallization is the {beta}{sup '}-phase structure with an orthorhombic (noncentrosymmetric) symmetry. The lines consisting of nonlinear optical {beta}{sup '}-Sm{sub 2}(MoO{sub 4}){sub 3} crystals are written at the surface of glasses by YAG laser irradiation (laser power: P=0.4 W, laser scanning speed: S=1-10 {mu}m/s), and, in particular, homogeneous crystal lines are formed at the laser scanning speed of 1 {mu}m/s. Refractive index changes (not crystallization) are also induced by YAG laser irradiation of P=0.4 W and a high laser scanning speed of S=25 {mu}m/s. The crystallization mechanism in the laser-irradiated region has been proposed. The present study demonstrates that the samarium atom heat processing is a technique for the writing of rare earth containing optical nonlinear/ferroelectric crystal lines in glass.

  7. Structure and properties of antimony-doped lanthanum molybdate La{sub 2}Mo{sub 2}O{sub 9}

    SciTech Connect

    Alekseeva, O. A. Verin, I. A.; Sorokina, N. I.; Kharitonova, E. P.; Voronkova, V. I.

    2011-05-15

    Polycrystalline samples of the composition La{sub 2}Mo{sub 2-x}Sb{sub x}O{sub 9-y}, where 0 {<=} x {<=} 0.05, were prepared by solid-phase synthesis. Single crystals of La{sub 2}Mo{sub 1.96}Sb{sub 0.04}O{sub 8.17} were obtained by spontaneous crystallization from flux. The structure of the metastable {beta}{sub ms} phase of this compound was determined at room temperature by X-ray diffraction. It was found that the La, Mo, and O1 atoms are displaced from the threefold axis on which they are located in the high-temperature {beta} phase. It was shown that molybdenum atoms in the crystal structure are partially replaced by antimony atoms, which are located on the threefold axis. In antimony-doped crystals, lanthanum atoms partially return to the site on the threefold axis and the coordination environment of molybdenum cations becomes more ordered, thus facilitating the stabilization of the cubic phase at room temperature. Calorimetric measurements (DSC) showed that the introduction of Sb as the dopant into the La{sub 2}Mo{sub 2}O{sub 9} structure leads to a decrease in the temperature of the {alpha} {yields} {beta} phase transition from 570 to 520 Degree-Sign C and to the partial suppression of this transition. The temperature behavior of the conductivity confirms the DSC data. Thus, doping with Sb contributes to the stabilization of the cubic phase at room temperature.

  8. Mechanical properties and strengthening of a Ni-25Mo-8Cr alloy containing Ni{sub 2}(Mo,Cr) precipitates

    SciTech Connect

    Kumar, M.; Vasudevan, V.K.

    1996-12-01

    The mechanical properties and mechanisms of deformation and strengthening of Haynes Alloy 242{sup tm}, a nominal Ni-25Mo-8Cr (in wt%) containing Ni{sub 2}(Mo,Cr) precipitates in a face-centered cubic matrix, are reported. Both solution treated, as well as aged samples (550--750 C, 1--1,200 h) were deformed to permanent strains of 1 and 6% in compression and to failure in tension. The deformation structures were observed by transmission electron microscopy. A two-fold increase in strength and tremendous strain hardening are observed as the short-range (SRO) to long-range ordering (LRO) transformation proceeds, although ductility remains high even in well-aged samples. Major contribution to strengthening and strain hardening comes from the precipitation of a high volume fraction of Ni{sub 2}(Mo,Cr) precipitates, with hardening in the solution treated samples and those aged for short periods being associated with the presence of SRO in the matrix. A transition in deformation mode, from glide of unit dislocations in planar arrays to profuse twinning, is observed as a function of aging time and imposed strain, twinning being observed in samples containing Ni{sub 2}(Mo,Cr) precipitates. A semi-quantitative model developed on the basis of precipitate size and mode of deformation (shearing, twinning, bypassing) is able to satisfactorily account for this transition. A presentation and discussion of these results, as well as those of the mechanisms of strengthening and strain hardening, are provided.

  9. Differential endosomal sorting of a novel P2Y12 purinoreceptor mutant.

    PubMed

    Cunningham, Margaret R; Nisar, Shaista P; Cooke, Alexandra E; Emery, Elizabeth D; Mundell, Stuart J

    2013-05-01

    P2Y12 receptor internalization and recycling play an essential role in ADP-induced platelet activation. Recently, we identified a patient with a mild bleeding disorder carrying a heterozygous mutation of P2Y12 (P341A) whose P2Y12 receptor recycling was significantly compromised. Using human cell line models, we identified key proteins regulating wild-type (WT) P2Y12 recycling and investigated P2Y12 -P341A receptor traffic. Treatment with ADP resulted in delayed Rab5-dependent internalization of P341A when compared with WT P2Y12 . While WT P2Y12 rapidly recycled back to the membrane via Rab4 and Rab11 recycling pathways, limited P341A recycling was observed, which relied upon Rab11 activity. Although minimal receptor degradation was evident, P341A was localized in Rab7-positive endosomes with considerable agonist-dependent accumulation in the trans-Golgi network (TGN). Rab7 activity is known to facilitate recruitment of retromer complex proteins to endosomes to transport cargo to the TGN. Here, we identified that P341A colocalized with Vps26; depletion of which blocked limited recycling and promoted receptor degradation. This study has identified key points of divergence in the endocytic traffic of P341A versus WT-P2Y12 . Given that these pathways are retained in human platelets, this research helps define the molecular mechanisms regulating P2Y12 receptor traffic and explain the compromised receptor function in the platelets of the P2Y12 -P341A-expressing patient. PMID:23387322

  10. Charge Disproportionation in Tetragonal La2MoO5 , a Small Band Gap Semiconductor Influenced by Direct Mo–Mo Bonding

    DOE PAGESBeta

    Colabello, Diane M.; Camino, Fernando E.; Huq, Ashfia; Hybertsen, Mark; Khalifah, Peter G.

    2014-12-31

    The structure of the novel compound La2MoO5 has been solved from powder X-ray and neutron diffraction data and belongs to the tetragonal space group P4/m (no. 83) with a = 12.6847(3) Å and c = 6.0568(2) Å and with Z = 8. It consists of equal proportions of bioctahedral (Mo2O10) and square prismatic (Mo2O8) dimers, both of which contain direct Mo-Mo bonds and are arranged in 1D chains. The Mo-Mo bond length in the Mo2O10dimers is 2.684(8) Å, while there are two types of Mo2O8 dimers with Mo-Mo bonds lengths of 2.22(2) and 2.28(2) Å. Although the average Mo oxidationmore » state in La2MoO5 is 4+, the very different Mo-Mo distances reflect the fact that the Mo2O10 dimers contain only Mo5+ (d(1)), while the prismatic Mo2O8 dimers only contain Mo3+ (d3), a result directly confirmed by density function theory calculations. This is due to the complete disproportionation of Mo4+, a phenomenon which has not previously been observed in solid-state compounds. La2MoO5 is diamagnetic, behavior which is not expected for a nonmetallic transition-metal oxide whose cation sites have an odd number of d-electrons. The resistivity displays the Arrhenius-type activated behavior expected for a semiconductor with a band gap of 0.5 eV, exhibiting an unusually small transport gap relative to other diamagnetic oxides. Diffuse reflectance studies indicate that La2MoO5 is a rare example of a stable oxide semiconductor with strong infrared absorbance. Lastly, we show that the d-orbital splitting associated with the Mo2O8 and Mo2O10 dimeric units can be rationalized using simple molecular orbital bonding concepts.« less

  11. Self-assembly of ultrathin Cu2MoS4 nanobelts for highly efficient visible light-driven degradation of methyl orange

    NASA Astrophysics Data System (ADS)

    Zhang, Ke; Chen, Wenxing; Lin, Yunxiang; Chen, Haiping; Haleem, Yasir A.; Wu, Chuanqiang; Ye, Fei; Wang, Tianxing; Song, Li

    2015-10-01

    We demonstrate ultrathin self-assembled Cu2MoS4 nanobelts synthesized by using Cu2O as the starting sacrificial template via a hydrothermal method. The nanobelts exhibit strong light absorption over a broad wavelength spectrum, suggesting their potential application as photocatalysts. The photocatalytic activity of nanobelts is evaluated by the degradation of Methyl Orange (MO) dye under visible light irradiation. Notably, the nanobelts can completely degrade 100 mL of 15 mg mL-1 MO in 20 minutes with excellent recycling and structural stability, suggesting their excellent photocatalytic performance. In comparison with a sheet-like sample, the high efficiency of the self-assembled Cu2MoS4 nanobelts is attributed to a high surface area and a unique band gap, agreeing with the nitrogen adsorption analysis and photoluminescence spectra. This study offers a self-assembled synthetic route to create new multifunctional nanoarchitectures composed of atomic layers, and thus may open a window for greatly extending potential applications in water pollution treatment, photocatalytic water-splitting, solar cells and other related fields.We demonstrate ultrathin self-assembled Cu2MoS4 nanobelts synthesized by using Cu2O as the starting sacrificial template via a hydrothermal method. The nanobelts exhibit strong light absorption over a broad wavelength spectrum, suggesting their potential application as photocatalysts. The photocatalytic activity of nanobelts is evaluated by the degradation of Methyl Orange (MO) dye under visible light irradiation. Notably, the nanobelts can completely degrade 100 mL of 15 mg mL-1 MO in 20 minutes with excellent recycling and structural stability, suggesting their excellent photocatalytic performance. In comparison with a sheet-like sample, the high efficiency of the self-assembled Cu2MoS4 nanobelts is attributed to a high surface area and a unique band gap, agreeing with the nitrogen adsorption analysis and photoluminescence spectra. This study

  12. Effect of oxygen barrier coatings on oxidation and embrittlement of Ti-6Al-2Sn-4Zr-2Mo foil in heat shield applications

    NASA Technical Reports Server (NTRS)

    Clark, R. K.; Unnam, J.; Wiedemann, K. E.

    1986-01-01

    Because of the loss of ductility with exposure to oxidizing conditions, long time applications of titanium alloys have been limited to temperatures below 700 K and short time applications have been limited to temperatures below 815 K. Oxygen barrier coatings for shielding Ti-6Al-2Sn-4Zr-2Mo alloy from oxidation during exposure to high temperatures were studied using foil gage specimens. The coatings included micrometer-thick sputtered SiO2 and chemical-vapor-deposited silicate layers both with and without an aluminum basecoat. The oxidation rates and resistance to embrittlement of the coated specimens were significantly better than those of the uncoated specimens.

  13. Coarsening Behavior and Plastic Flow of Ti-6Al-2Sn-4Zr-2Mo-0.1Si with an Ultrafine Microstructure

    NASA Astrophysics Data System (ADS)

    Semiatin, S. L.; Sun, F.; Crist, E. M.; Yu, K. O.; Sargent, G. A.; Sanders, D. G.

    2016-07-01

    Coarsening behavior and superplastic-flow response of Ti-6Al-2Sn-4Zr-2Mo-0.1Si with an ultrafine, equiaxed-alpha microstructure were interpreted in the context of classical models. Static coarsening was shown to follow modified Lifshitz-Slyosov-Wagner (LSW) kinetics. The rate of dynamic coarsening was six times more rapid than the corresponding static rate due to enhanced diffusion of solutes in the beta matrix. Last, a generalized constitutive equation was used to interpret the dependence of flow stress on strain/dynamic coarsening, strain rate, and temperature.

  14. Controllable self-assembly of a novel Bi2MoO6-based hybrid photocatalyst: excellent photocatalytic activity under UV, visible and near-infrared irradiation.

    PubMed

    Hao, Yuchen; Dong, Xiaoli; Zhai, Shangru; Wang, Xiuying; Ma, Hongchao; Zhang, Xiufang

    2016-05-01

    Herein, using a simple one-step method, a Bi2MoO6-based photocatalyst with novel ultrathin nanohollow structure and simultaneous sub-10 nm Bi nanoparticles and sub-1 nm graphitic nitrogen-doped carbon nanodot (NCD) modification were successfully obtained. The coordination impact of the novel structure, SPR effect of Bi nanoparticles, up-conversion performance of graphitic NCDs and cooperative electronic capture properties of Bi metal and NCDs make the hybrid simultaneously exhibit fast charge separation and broad spectrum photocatalytic activity under UV, visible and near-infrared irradiation, leading to excellent photooxidation and photoreduction performance. PMID:27026588

  15. Absorption enhancement in CH3NH3PbI3 solar cell using a TiO2/MoS2 nanocomposite electron selective contact

    NASA Astrophysics Data System (ADS)

    Imran Ahmed, Muhammad; Hussain, Zakir; Khalid, Amir; Noman Amin, Hafiz Muhammad; Habib, Amir

    2016-04-01

    In the present contribution, perovskite absorbers have been combined with few layer thick MoS2 semiconductor to put together a solar cell allowing broad spectrum harvesting of solar radiations. Such modification allows to achieve solar light harvesting at the band edges, addressing a drawback of CH3NH3PbI3 absorbers. We recorded an improved efficiency from 3.7% to 4.3% on the back of this methodology. We have also worked out a novel methodology to synthesize TiO2/MoS2 nanocomposite by in situ dispersion of liquid exfoliated MoS2 sheets in the sol gel reaction.

  16. Coarsening Behavior and Plastic Flow of Ti-6Al-2Sn-4Zr-2Mo-0.1Si with an Ultrafine Microstructure

    NASA Astrophysics Data System (ADS)

    Semiatin, S. L.; Sun, F.; Crist, E. M.; Yu, K. O.; Sargent, G. A.; Sanders, D. G.

    2016-09-01

    Coarsening behavior and superplastic-flow response of Ti-6Al-2Sn-4Zr-2Mo-0.1Si with an ultrafine, equiaxed-alpha microstructure were interpreted in the context of classical models. Static coarsening was shown to follow modified Lifshitz-Slyosov-Wagner (LSW) kinetics. The rate of dynamic coarsening was six times more rapid than the corresponding static rate due to enhanced diffusion of solutes in the beta matrix. Last, a generalized constitutive equation was used to interpret the dependence of flow stress on strain/dynamic coarsening, strain rate, and temperature.

  17. Negative magnetization of Li2Ni2Mo3O12 including two spin subsystems, distorted honeycomb lattice and linear chain

    NASA Astrophysics Data System (ADS)

    Hase, Masashi; Pomjakushin, Vladimir Yu; Sikolenko, Vadim; Keller, Lukas; Dönni, Andreas; Kitazawa, Hideaki

    2012-12-01

    We studied magnetism of a spin-1 insulating substance Li2Ni2Mo3O12. The spin system consists of distorted honeycomb lattices and linear chains of Ni2+ spins. A magnetic phase transition occurs at Tc = 8.0 K in the zero magnetic field. In low magnetic fields, the magnetization increases rapidly below Tc, decreases below 7 K and becomes negative at low temperatures. We determined the magnetic structure using neutron powder diffraction data. The honeycomb lattices and linear chains show antiferromagnetic and ferromagnetic long-range order, respectively. We discuss the origin of the negative magnetization.

  18. A new acid-base indicator containing complex: Hydrothermal synthesis, crystal structure and properties of [Cd(en)2(H2O)2](MO)2

    NASA Astrophysics Data System (ADS)

    Ma, Kui-Rong; Shi, Jing; Zhang, Dao-Jun; Xu, Jia-Ning

    2012-04-01

    The first example of cadmium complex containing methyl orange [MO, (CH3)2NC6H4N = NC6H4SO3Na], formulated as [Cd(en)2(H2O)2](MO)21 (en = ethylenediamine) was synthesized hydrothermally and characterized by single-crystal X-ray diffraction, IR, XRD, elemental analysis and Raman spectroscopic analysis. Compound 1 display a two-dimensional supramolecular layer structure with ladder-like supramolecular chain by X-ray crystallographic analysis. MO anion immobilized by H-bonds, as acid-base indicator, shows a similar behavior in comparison with its solution counterpart in terms of response to pH.

  19. New Mechanism for the Enhancement of sd Dominance in Interacting Boson Models

    NASA Astrophysics Data System (ADS)

    Dukelsky, J.; Pittel, S.

    2001-05-01

    We introduce an exactly solvable model for interacting bosons that extend up to high spin and interact through a repulsive pairing force. The model exhibits a phase transition to a state with almost complete sd dominance. The repulsive pairing interaction that underlies the model has a natural microscopic origin in the Pauli exclusion principle between constituent nucleons. As such, repulsive pairing between bosons seems to provide a new mechanism for the enhancement of sd dominance, giving further support for the validity of the sd interacting boson model.

  20. Oxidative extraction and ion-exchange of lithium in Li/sub 2/MoO/sub 3/: Synthesis of Li/sub 2-x/MoO/sub 3/ (02/MoO/sub 3//sup +/

    SciTech Connect

    Gopalakrishnan, J.; Bhat, V.

    1987-06-01

    It is shown that lithium can be oxidatively extracted from Li/sub 2/MoO/sub 3/ at room temperature using Br/sub 2/ in CHCl/sub 3/. The delithiated oxides, Li/sub 2-x/MoO/sub 3/ (O < less than or equal to 1.5) retain the parent ordered rocksalt structure. Complete removal of lithium from Li/sub 2/MiO/sub 3/ using Br/sub 2/ in CH/sub 3/CN results in a poorly crystalline MoO/sub 3/ that transforms to the stable structure at 280/sup 0/C. Li/sub 2/MiO/sub 3/ undergoes topotactic ion-exchange in aqueous H/sub 2/SO/sub 4/ to yield a new protonated oxide, H/sub 2/MoO/sub 3/.

  1. P2Y12 expression and function in alternatively activated human microglia

    PubMed Central

    Ase, Ariel R.; Kinsara, Angham; Rao, Vijayaraghava T.S.; Michell-Robinson, Mackenzie; Leong, Soo Yuen; Butovsky, Oleg; Ludwin, Samuel K.; Séguéla, Philippe; Bar-Or, Amit; Antel, Jack P.

    2015-01-01

    Objective: To investigate and measure the functional significance of altered P2Y12 expression in the context of human microglia activation. Methods: We performed in vitro and in situ experiments to measure how P2Y12 expression can influence disease-relevant functional properties of classically activated (M1) and alternatively activated (M2) human microglia in the inflamed brain. Results: We demonstrated that compared to resting and classically activated (M1) human microglia, P2Y12 expression is increased under alternatively activated (M2) conditions. In response to ADP, the endogenous ligand of P2Y12, M2 microglia have increased ligand-mediated calcium responses, which are blocked by selective P2Y12 antagonism. P2Y12 antagonism was also shown to decrease migratory and inflammatory responses in human microglia upon exposure to nucleotides that are released during CNS injury; no effects were observed in human monocytes or macrophages. In situ experiments confirm that P2Y12 is selectively expressed on human microglia and elevated under neuropathologic conditions that promote Th2 responses, such as parasitic CNS infection. Conclusion: These findings provide insight into the roles of M2 microglia in the context of neuroinflammation and suggest a mechanism to selectively target a functionally unique population of myeloid cells in the CNS. PMID:25821842

  2. Two disparate ligand binding sites in the human P2Y1 receptor

    PubMed Central

    Zhang, Dandan; Gao, Zhan-Guo; Zhang, Kaihua; Kiselev, Evgeny; Crane, Steven; Wang, Jiang; Paoletta, Silvia; Yi, Cuiying; Ma, Limin; Zhang, Wenru; Han, Gye Won; Liu, Hong; Cherezov, Vadim; Katritch, Vsevolod; Jiang, Hualiang; Stevens, Raymond C.; Jacobson, Kenneth A.; Zhao, Qiang; Wu, Beili

    2015-01-01

    In response to adenosine 5′-diphosphate, the P2Y1 receptor (P2Y1R) facilitates platelet aggregation, and thus serves as an important antithrombotic drug target. Here we report the crystal structures of the human P2Y1R in complex with a nucleotide antagonist MRS2500 at 2.7Å resolution, and with a non-nucleotide antagonist BPTU at 2.2Å resolution. The structures reveal two distinct ligand binding sites, providing atomic details of P2Y1R’s unique ligand binding modes. MRS2500 recognizes a binding site within the seven transmembrane bundle of P2Y1R, which, however, is different in shape and location from the nucleotide binding site in previously determined P2Y12R structure. BPTU binds to an allosteric pocket on the external receptor interface with the lipid bilayer, making it the first structurally characterized selective G protein-coupled receptor (GPCR) ligand located entirely outside of the helical bundle. These high-resolution insights into P2Y1R should enable discovery of new orthosteric and allosteric antithrombotic drugs with reduced adverse effects. PMID:25822790

  3. Structural and functional evolution of the P2Y12-like receptor group

    PubMed Central

    Hermsdorf, Thomas; Engemaier, Eva; Engel, Kathrin; Liebscher, Ines; Thor, Doreen; Zierau, Klaas; Römpler, Holger; Schulz, Angela

    2007-01-01

    Metabotropic pyrimidine and purine nucleotide receptors (P2Y receptors) belong to the superfamily of G protein-coupled receptors (GPCR). They are distinguishable from adenosine receptors (P1) as they bind adenine and/or uracil nucleotide triphosphates or diphosphates depending on the subtype. Over the past decade, P2Y receptors have been cloned from a variety of tissues and species, and as many as eight functional subtypes have been characterized. Most recently, several members of the P2Y12-like receptor group, which includes the clopidogrel-sensitive ADP receptor P2Y12, have been deorphanized. The P2Y12-like receptor group comprises several structurally related GPCR which, however, display heterogeneous agonist specificity including nucleotides, their derivatives, and lipids. Besides the established function of P2Y12 in platelet activation, expression in macrophages, neuronal and glial cells as well as recent results from functional studies implicate that several members of this group may have specific functions in neurotransmission, inflammation, chemotaxis, and response to tissue injury. This review focuses specifically on the structure-function relation and shortly summarizes some aspects of the physiological relevance of P2Y12-like receptor members. PMID:18404440

  4. Composition and structure of acid leached LiMn{sub 2-y}Ti{sub y}O{sub 4} (0.2<=y<=1.5) spinels

    SciTech Connect

    Avdeev, Georgi; Amarilla, Jose Manuel; Rojo, Jose Maria; Petrov, Kostadin; Rojas, Rosa Maria

    2009-12-15

    Lithium manganese titanium spinels, LiMn{sub 2-y}Ti{sub y}O{sub 4}, (0.2<=y<=1.5) have been synthesized by solid-state reaction between TiO{sub 2} (anatase), Li{sub 2}CO{sub 3} and MnCO{sub 3}. Li{sup +} was leached from the powdered reaction products by treatment in excess of 0.2 N HCl at 85 deg. C for 6 h, under reflux. The elemental composition of the acidic solution and solid residues of leaching has been determined by complexometric titration, atomic absorption spectroscopy and X-ray fluorescence analysis. Powder X-ray diffraction was used for structural characterization of the crystalline fraction of the solid residues. It has been found that the amount of Li{sup +} leached from LiMn{sub 2-y}Ti{sub y}O{sub 4} decreases monotonically with increasing y in the interval 0.2<=y<=1.0 and abruptly drops to negligibly small values for y>1.0. The content of Mn and Li in the liquid phase and of Mn and Ti in the solid (amorphous plus crystalline) residue, were related to the composition and cation distribution in the pristine compounds. A new formal chemical equation describing the process of leaching and a mechanism of the structural transformation undergone by the initial solids as a result of Li{sup +} removal has been proposed. - Graphical abstract: Schematic representation of the acid leaching of LiMn{sub 2-y}Ti{sub y}O{sub 4} (0.2<=y<=1.0).

  5. 5-OMe-UDP is a potent and selective P2Y(6)-receptor agonist.

    PubMed

    Ginsburg-Shmuel, Tamar; Haas, Michael; Schumann, Marlen; Reiser, Georg; Kalid, Ori; Stern, Noa; Fischer, Bilha

    2010-02-25

    P2Y nucleotide receptors (P2Y-Rs) play important physiological roles. However, most of the P2Y-R subtypes are still lacking potent and selective agonists and antagonists. Based on data mining analysis of binding interactions in 44 protein-uridine nucleos(t)ides complexes, we designed uracil nucleotides, substituted at the C5/C6 position. All C6-substituted derivatives were inactive at the P2Y(2,4,6)-Rs, while out of the C5-substituted analogues, only 5-OMe-UD(T)P showed activity. To rationalize the data, the ionization and conformation of these analogues were evaluated. The pK(a) values of most analogues substituted at the C5/C6 positions were unaltered compared to UTP (pK(a) 9.42), except for 5-F-UTP nucleotide (pK(a) 7.85). C6-substituted analogues adopt the syn or high-syn conformations, which are disfavored by the receptors, while 5-OMe-UD(T)P adopt the favored anti conformation. Furthermore, 5-OMe-UDP adopts the S sugar puckering, which is the conformation preferred by the P2Y(6)-R, but not the P2Y(2)- or P2Y(4)-Rs. 5-OMe-UDP fulfills the conformational and H-bonding requirements of P2Y(6)-R, thus, making a potent P2Y(6)-R agonist (EC(50) 0.08 microM), more than UDP (EC(50) 0.14 microM). PMID:20095577

  6. High pressure studies of A2Mo3O12 negative thermal expansion materials (A2=Al2, Fe2, FeAl, AlGa)

    NASA Astrophysics Data System (ADS)

    Young, Lindsay; Gadient, Jennifer; Gao, Xiaodong; Lind, Cora

    2016-05-01

    High pressure powder X-ray diffraction studies of several A2Mo3O12 materials (A2=Al2, Fe2, FeAl, and AlGa) were conducted up to 6-7 GPa. All materials adopted a monoclinic structure under ambient conditions, and displayed similar phase transition behavior upon compression. The initial isotropic compressibility first became anisotropic, followed by a small but distinct drop in cell volume. These patterns could be described by a distorted variant of the ambient pressure polymorph. At higher pressures, a distinct high pressure phase formed. Indexing results confirmed that all materials adopted the same high pressure phase. All changes were reversible on decompression, although some hysteresis was observed. The similarity of the high pressure cells to previously reported Ga2Mo3O12 suggested that this material undergoes the same sequence of transitions as all materials investigated in this paper. It was found that the transition pressures for all phase changes increased with decreasing radius of the A-site cations.

  7. Novel Na2Mo4O13/α-MoO3 hybrid material as highly efficient CWAO catalyst for dye degradation at ambient conditions

    PubMed Central

    Zhang, Zhang; Yang, Ruoyan; Gao, Yanshan; Zhao, Yufei; Wang, Junyang; Huang, Liang; Guo, Jiang; Zhou, Tuantuan; Lu, Peng; Guo, Zhanhu; Wang, Qiang

    2014-01-01

    We report a novel hybrid material Na2Mo4O13/α-MoO3 as highly efficient catalytic wet air oxidation (CWAO) catalyst, which showed the highest ever activity at room temperature and atmosphere pressure for the degradation of cationic red GTL. SEM and TEM analyses indicated that this hybrid catalyst has bamboo-shaped nanofiber morphology. In view of practical applications, the influence of some key parameters including operation temperature, catalyst calcination temperature, and the volume of dye wastewater have been optimized. The mechanism for the superior catalytic performance was investigated. XRD, XPS, and ESR suggested the Na2Mo4O13/α-MoO3 hybrid catalyst possesses more O2− ions in the oxygen deficient regions than neat α-MoO3, promoting the formation of active ·OH radicals and resulting in a higher activity. Considering the facile preparation and its superior activity, this novel catalyst is promising for practical dye wastewater treatment. PMID:25348943

  8. A Deformation Mechanism Map for the 1.23Cr-1.2Mo-0.26V Rotor Steel and Its Verification Using Neural Networks

    NASA Astrophysics Data System (ADS)

    Bano, Nafisa; Koul, Ashok K.; Nganbe, Michel

    2014-04-01

    A deformation mechanism map is constructed for the 1.23Cr-1.2Mo-0.26V rotor steel as a function of temperature, stress, and strain rate using published creep test results and the current understanding of time dependent deformation mechanisms operative in complex engineering alloys. Instead of diffusional creep, grain boundary sliding (GBS) accommodated by different deformation processes is considered dominant at lower strain rates. The GBS dominated region is further sub-divided into two parts, where GBS is accommodated by wedge type cracking at temperatures below 0.5 T/ T m and the accommodation process changes to creep cavitation at temperatures above 0.5 T/ T m. The map is verified using experimental data and artificial neural network modeling. The proposed artificial neural network model is capable of predicting the dominance of different deformation mechanisms in 1.23Cr-1.2Mo-0.26V steel over a wide range of stress and temperature. This modeling procedure can potentially be used to construct or expand deformation mechanism maps for other engineering alloys.

  9. Hydrothermal synthesis of CdS/Bi2MoO6 heterojunction photocatalysts with excellent visible-light-driven photocatalytic performance

    NASA Astrophysics Data System (ADS)

    Feng, Yi; Yan, Xu; Liu, Chunbo; Hong, Yuanzhi; Zhu, Lin; Zhou, Mingjun; Shi, Weidong

    2015-10-01

    A novel CdS/Bi2MoO6 heterojunction photocatalysts were successfully prepared via two-step hydrothermal methods. The prepared samples were characterized by various physicochemical techniques, such as XRD, SEM, TEM, HRTEM, XPS, UV-vis and PL. The obtained samples exhibited highly photocatalytic activity toward the degradation of the different kinds of organic dyes and tetracycline in aqueous solution under visible light irradiation (λ > 420 nm). The optimum photocatalytic efficiency of CdS-2 sample for the degradation rhodamine B (RhB) was about 25.3 and 3.7 times higher than that of individual CdS and Bi2MoO6, respectively. In addition, the possible photocatalytic mechanism was analyzed by different active species trapping experiments. The results indicated that the h+ and rad O2- were the main active species for the photocatalytic degradation of RhB. Moreover, the prepared sample shows good stability and recyclability properties which are beneficial for its practical application.

  10. Effects of rare earth substitution on the optical properties of Bi{sub 2}MoO{sub 6} for coloring applications

    SciTech Connect

    Kumari, L. Sandhya; Prabhakar Rao, P.; Sameera, S.; James, Vineetha; Koshy, Peter

    2015-10-15

    Highlights: • New class of colored compounds BiREMoO{sub 6} (RE = Pr, Nd, Sm, Tb, Yb) was synthesized. • The substitution of RE gently red shifts the absorption edge to low energy side. • The differences in band gap depend on the position of the RE f bands. • The yellow colored compounds demonstrated good coloration to plastics. - Abstract: A new class of colored inorganic compounds, BiREMoO{sub 6} (RE = Pr, Nd, Sm, Tb and Yb) has been synthesized by a solid state route. The substitution of different rare earths for Bi{sup 3+} in Bi{sub 2}MoO{sub 6} produces visible light responsive compounds by gently red shifting the absorption edge to low energy side. The visible light absorption is based on the charge transfer transitions from O{sub 2p} valence band to conduction band made of primary Mo{sub 4d} and secondary Bi{sub 6p}. The substitution of RE{sup 3+} introduces partially occupied 4f electronic levels in between the band gap and the position of 4f level depend on the number of f electrons which allows tuning the band gap. Thus the rare earth substitution provides an opportunity to tailor the band gap of Bi{sub 2}MoO{sub 6} from 2.99 eV to 2.19 eV. The developed compounds exhibited different shades of yellow hue and demonstrated good coloration to plastics.

  11. Synthesis of Hierarchical Sb2MoO6 Architectures and Their Electrochemical Behaviors as Anode Materials for Li-Ion Batteries.

    PubMed

    Lu, Xuan; Wang, Zhenyu; Lu, Lu; Yang, Guang; Niu, Chunming; Wang, Hongkang

    2016-07-18

    We report a facile microwave-hydrothermal synthesis of hierarchical Sb2MoO6 architectures assembled from single-crystalline nanobelts, which are first demonstrated as anode materials for lithium-ion batteries (LIBs) with superior electrochemical properties. Sb2MoO6 delivers a high initial reversible capacity of ∼1140 mA h/g at 200 mA/g with large initial Coulombic efficiency of ∼89%, and a reversible capacity of ∼878 mA h/g after 100 cycles at 200 mA/g. As a new anode, the electrochemical behaviors are investigated through ex situ TEM and XPS measurements, revealing that the superior electrochemical performance is attributed to the novel hierarchical structures and the synergistic interaction between both the active Sb- and Mo-species, in which the in situ generated Li2O-MoOx serves as matrix and efficiently buffers the volume changes of the Li-Sb alloying-dealloying upon cycling. PMID:27378321

  12. PTM-SD: a database of structurally resolved and annotated posttranslational modifications in proteins

    PubMed Central

    Craveur, Pierrick; Rebehmed, Joseph; de Brevern, Alexandre G.

    2014-01-01

    Posttranslational modifications (PTMs) define covalent and chemical modifications of protein residues. They play important roles in modulating various biological functions. Current PTM databases contain important sequence annotations but do not provide informative 3D structural resource about these modifications. Posttranslational modification structural database (PTM-SD) provides access to structurally solved modified residues, which are experimentally annotated as PTMs. It combines different PTM information and annotation gathered from other databases, e.g. Protein DataBank for the protein structures and dbPTM and PTMCuration for fine sequence annotation. PTM-SD gives an accurate detection of PTMs in structural data. PTM-SD can be browsed by PDB id, UniProt accession number, organism and classic PTM annotation. Advanced queries can also be performed, i.e. detailed PTM annotations, amino acid type, secondary structure, SCOP class classification, PDB chain length and number of PTMs by chain. Statistics and analyses can be computed on a selected dataset of PTMs. Each PTM entry is detailed in a dedicated page with information on the protein sequence, local conformation with secondary structure and Protein Blocks. PTM-SD gives valuable information on observed PTMs in protein 3D structure, which is of great interest for studying sequence–structure– function relationships at the light of PTMs, and could provide insights for comparative modeling and PTM predictions protocols. Database URL: PTM-SD can be accessed at http://www.dsimb.inserm.fr/dsimb_tools/PTM-SD/. PMID:24857970

  13. SdPI, The First Functionally Characterized Kunitz-Type Trypsin Inhibitor from Scorpion Venom

    PubMed Central

    Li, Tian; He, Yawen; Ma, Yibao; Chen, Zongyun; Wu, Yingliang; Li, Wenxin; Cao, Zhijian

    2011-01-01

    Background Kunitz-type venom peptides have been isolated from a wide variety of venomous animals. They usually have protease inhibitory activity or potassium channel blocking activity, which by virtue of the effects on predator animals are essential for the survival of venomous animals. However, no Kunitz-type peptides from scorpion venom have been functionally characterized. Principal Findings A new Kunitz-type venom peptide gene precursor, SdPI, was cloned and characterized from a venom gland cDNA library of the scorpion Lychas mucronatus. It codes for a signal peptide of 21 residues and a mature peptide of 59 residues. The mature SdPI peptide possesses a unique cysteine framework reticulated by three disulfide bridges, different from all reported Kunitz-type proteins. The recombinant SdPI peptide was functionally expressed. It showed trypsin inhibitory activity with high potency (Ki = 1.6×10−7 M) and thermostability. Conclusions The results illustrated that SdPI is a potent and stable serine protease inhibitor. Further mutagenesis and molecular dynamics simulation revealed that SdPI possesses a serine protease inhibitory active site similar to other Kunitz-type venom peptides. To our knowledge, SdPI is the first functionally characterized Kunitz-type trypsin inhibitor derived from scorpion venom, and it represents a new class of Kunitz-type venom peptides. PMID:22087336

  14. Identifying and rationalizing the morphological, structural, and optical properties of {\\boldsymbol{\\beta }}-Ag2MoO4 microcrystals, and the formation process of Ag nanoparticles on their surfaces: combining experimental data and first-principles calculations

    NASA Astrophysics Data System (ADS)

    Fabbro, Maria T.; Saliby, Carla; Rios, Larissa R.; La Porta, Felipe A.; Gracia, Lourdes; Li, Máximo S.; Andrés, Juan; Santos, Luís P. S.; Longo, Elson

    2015-12-01

    We present a combined theoretical and experimental study on the morphological, structural, and optical properties of β-Ag2MoO4 microcrystals. β-Ag2MoO4 samples were prepared by a co-precipitation method. The nucleation and formation of Ag nanoparticles on β-Ag2MoO4 during electron beam irradiation were also analyzed as a function of electron beam dose. These events were directly monitored in real-time using in situ field emission scanning electron microscopy (FE-SEM). The thermodynamic equilibrium shape of the β-Ag2MoO4 crystals was built with low-index surfaces (001), (011), and (111) through a Wulff construction. This shape suggests that the (011) face is the dominating surface in the ideal morphology. A significant increase in the values of the surface energy for the (011) face versus those of the other surfaces was observed, which allowed us to find agreement between the experimental and theoretical morphologies. Our investigation of the different morphologies and structures of the β-Ag2MoO4 crystals provided insight into how the crystal morphology can be controlled so that the surface chemistry of β-Ag2MoO4 can be tuned for specific applications. The presence of structural disorder in the tetrahedral [MoO4] and octahedral [AgO6] clusters, the building blocks of β-Ag2MoO4, was used to explain the experimentally measured optical properties.

  15. Luminescent properties and energy transfer process of Sm3+-Eu3+ co-doped MY2(MoO4)4 (M=Ca, Sr and Ba) red-emitting phosphors

    NASA Astrophysics Data System (ADS)

    Ye, Menglin; Zhou, Gaojian; Zhou, Liqun; Lu, Di; Li, Yue; Xiong, Xing; Yang, Kunzhou; Chen, Menghuan; Pan, Yaxi; Wu, Peng; Wang, Zheng; Liu, Hongying; Xia, Qinghua

    2016-09-01

    MY2(MoO4)4:Sm3+ and MY2(MoO4)4:xSm3+,yEu3+ (M=Ca, Sr and Ba) phosphors were successfully prepared using solid-state reaction route, and their luminescent properties and energy transfer process from Sm3+ to Eu3+ were systematically investigated. The results indicate that MY2(MoO4)4:Sm3+ phosphors can be effectively excited by 407 nm near UV light originating from the 6H5/2 → 4F7/2 transition of Sm3+, and exhibit a satisfactory red emission at 646 nm attributed to the 4G5/2 → 6H9/2 transition of Sm3+, in which the emission intensity of SrY2(MoO4)4:Sm3+ is the strongest among the MY2(MoO4)4:Sm3+ (M=Ca, Sr and Ba) phosphors. For Eu3+ co-doped MY2(MoO4)4:Sm3+ samples, with increasing Eu3+ doping content, the main emission peaks of Sm3+ (approximately 646 nm) are decreased, but the emission peaks and intensity of Eu3+ are increased while the maximum intensity of luminescence at the Eu3+ concentration 0.9. The introduction of Eu3+ in the MY2(MoO4)4:Sm3+ phosphors can remarkably generate a strong emission line at 616 nm, originating from the 5D0→7F2 transition of Eu3+ and Sm3+ (4G5/2) → Eu3+ (5D0) effective energy transfer process. The energy transfer mechanism from Sm3+ to Eu3+ was discussed in detail.

  16. NaYF{sub 4}:Er,Yb/Bi{sub 2}MoO{sub 6} core/shell nanocomposite: A highly efficient visible-light-driven photocatalyst utilizing upconversion

    SciTech Connect

    Sun, Yuanyuan; Wang, Wenzhong Sun, Songmei; Zhang, Ling

    2014-04-01

    Highlights: • Design and synthesis of NaYF{sub 4}:Er,Yb/Bi{sub 2}MoO{sub 6} based on upconversion. • NaYF{sub 4}:Er,Yb/Bi{sub 2}MoO{sub 6} nanocomposite was prepared for the first time. • Core–shell structure benefits the properties. • Upconversion contributed to the enhanced photocatalytic activity. • Helps to understand the functionality of new type photocatalysts. - Abstract: NaYF{sub 4}:Er,Yb/Bi{sub 2}MoO{sub 6} core/shell nanocomposite was designed and prepared for the first time based on upconversion. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution TEM (HRTEM), energy dispersive X-ray spectroscopy (EDS) and diffuse reflectance spectra (DRS). The results revealed that the as-synthesized NaYF{sub 4}:Er,Yb/Bi{sub 2}MoO{sub 6} consisted of spheres with a core diameter of about 26 nm and a shell diameter of around 6 nm. The core was upconversion illuminant NaYF{sub 4}:Er,Yb and the shell was Bi{sub 2}MoO{sub 6} around the core, which was confirmed by EDS. The NaYF{sub 4}:Er,Yb/Bi{sub 2}MoO{sub 6} exhibited higher photocatalytic activity for the photodecomposition of Rhodamine B (RhB) under the irradiation of Xe lamp and green light emitting diode (g-LED). The mechanism of the high photocatalytic activity was discussed by photoluminescence spectra (PL), which is mainly attributed to upconversion of NaYF{sub 4}:Er,Yb in the NaYF{sub 4}:Er,Yb/Bi{sub 2}MoO{sub 6} nanocomposite and the core–shell structure.

  17. Preparation of transparent Cu2Y2O5 thin films by RF magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Chiu, Te-Wei; Chang, Chih-Hao; Yang, Li-Wei; Wang, Yung-Po

    2015-11-01

    Cu2Y2O5 thin films were deposited on non-alkali glass substrates by RF magnetron sputtering. Its crystal structure, microstructure, optical property, mechanical property, and antibacterial activity were investigated by grazing-incidence X-ray diffraction, transmittance spectra, nanoindenter, and antibiotics test, respectively. A single-phase of Cu2Y2O5 was obtained while annealing at 700 °C in air and its optical transparency was >80% in the visible region. The hardness and elastic modulus of the film were 6.7 GPa and 82 GPa, respectively. Antibiotics testing result revealed that Cu2Y2O5 surface had a superior antibacterial performance even at a dark environment. Therefore, Cu2Y2O5 is a promising novel transparent antibacterial hard coating material.

  18. Clinical effects and outcomes with new P2Y12 inhibitors in ACS.

    PubMed

    Collet, Jean-Philippe; O'Connor, Stephen

    2012-02-01

    Thienopyridines have become the cornerstone of treatment for percutaneous coronary intervention although no survival benefit has ever been shown with clopidogrel despite increasing loading doses. Newly developed P2Y12 inhibitors are more potent, more predictable, and have a faster onset of action than clopidogrel, characteristics that make them particularly attractive for high-risk percutaneous coronary intervention (PCI). Four new P2Y12 inhibitors have been tested each of them having particular individual properties. Prasugrel is an oral pro-drug leading to irreversible blockade of the P2Y12 receptor and is approved worldwide for ACS PCI. Ticagrelor is a direct-acting and reversible inhibitor of the P2Y12 receptor with potentially more pleiotropic effects. Cangrelor is an intravenous direct and reversible inhibitor of the P2Y12 receptor providing the highest level of inhibition, and elinogrel is an intravenous and oral P2Y12 antagonist with a direct and reversible action. Both prasugrel and ticagrelor, opposed to clopidogrel, have shown that stronger P2Y12 inhibition led respectively to significant 19 and 16% relative risk reduction of a similar primary end point combining cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke. Both drugs showed a significant 0.6% absolute excess of TIMI major bleeding not related to CABG surgery. Because in clinical trials, patients perceived to be at higher risk of bleeding usually are excluded, the risk of major and even fatal bleeding might even be higher in a 'real-world' setting, i.e. in the elderly patient with comorbidities. On the other hand, these newly developed P2Y12 inhibitors decrease mortality after PCI compared with clopidogrel. The risk/benefit ratio is particularly favorable in PCI for patients with STEMI. PMID:21895760

  19. Impaired Cognition after Stimulation of P2Y1 Receptors in the Rat Medial Prefrontal Cortex

    PubMed Central

    Koch, Holger; Bespalov, Anton; Drescher, Karla; Franke, Heike; Krügel, Ute

    2015-01-01

    We hypothesize that cortical ATP and ADP accumulating in the extracellular space, eg during prolonged network activity, contribute to a decline in cognitive performance in particular via stimulation of the G protein-coupled P2Y1 receptor (P2Y1R) subtype. Here, we report first evidence on P2Y1R-mediated control of cognitive functioning in rats using bilateral microinfusions of the selective agonist MRS2365 into medial prefrontal cortex (mPFC). MRS2365 attenuated prepulse inhibition of the acoustic startle reflex while having no impact on startle amplitude. Stimulation of P2Y1Rs deteriorated performance accuracy in the delayed non-matching to position task in a delay dependent manner and increased the rate of magazine entries consistent with both working memory disturbances and impaired impulse control. Further, MRS2365 significantly impaired performance in the reversal learning task. These effects might be related to MRS2365-evoked increase of dopamine observed by microdialysis to be short-lasting in mPFC and long-lasting in the nucleus accumbens. P2Y1Rs were identified on pyramidal cells and parvalbumin-positive interneurons, but not on tyrosine hydroxylase-positive fibers, which argues for an indirect activation of dopaminergic afferents in the cortex by MRS2365. Collectively, these results suggest that activation of P2Y1Rs in the mPFC impairs inhibitory control and behavioral flexibility mediated by increased mesocorticolimbic activity and local disinhibition. PMID:25027332

  20. Effects of P2Y12 receptor antagonists beyond platelet inhibition - comparison of ticagrelor with thienopyridines.

    PubMed

    Nylander, Sven; Schulz, Rainer

    2016-04-01

    The effect and clinical benefit of P2Y12 receptor antagonists may not be limited to platelet inhibition and the prevention of arterial thrombus formation. Potential additional effects include reduction of the pro-inflammatory role of activated platelets and effects related to P2Y12 receptor inhibition on other cells apart from platelets. P2Y12 receptor antagonists, thienopyridines and ticagrelor, differ in their mode of action being prodrugs instead of direct acting and irreversibly instead of reversibly binding to P2Y12 . These key differences may provide different potential when it comes to additional effects. In addition to P2Y12 receptor blockade, ticagrelor is unique in having the only well-documented additional target of inhibition, the equilibrative nucleoside transporter 1. The current review will address the effects of P2Y12 receptor antagonists beyond platelets and the protection against arterial thrombosis. The discussion will include the potential for thienopyridines and ticagrelor to mediate anti-inflammatory effects, to conserve vascular function, to affect atherosclerosis, to provide cardioprotection and to induce dyspnea. PMID:26758983

  1. Pressure coefficients for direct optical transitions in MoS2, MoSe2, WS2, and WSe2 crystals and semiconductor to metal transitions.

    PubMed

    Dybała, F; Polak, M P; Kopaczek, J; Scharoch, P; Wu, K; Tongay, S; Kudrawiec, R

    2016-01-01

    The electronic band structure of MoS2, MoSe2, WS2, and WSe2, crystals has been studied at various hydrostatic pressures experimentally by photoreflectance (PR) spectroscopy and theoretically within the density functional theory (DFT). In the PR spectra direct optical transitions (A and B) have been clearly observed and pressure coefficients have been determined for these transitions to be: αA = 2.0 ± 0.1 and αB = 3.6 ± 0.1 meV/kbar for MoS2, αA = 2.3 ± 0.1 and αB = 4.0 ± 0.1 meV/kbar for MoSe2, αA = 2.6 ± 0.1 and αB = 4.1 ± 0.1 meV/kbar for WS2, αA = 3.4 ± 0.1 and αB = 5.0 ± 0.5 meV/kbar for WSe2. It has been found that these coefficients are in an excellent agreement with theoretical predictions. In addition, a comparative study of different computational DFT approaches has been performed and analyzed. For indirect gap the pressure coefficient have been determined theoretically to be -7.9, -5.51, -6.11, and -3.79, meV/kbar for MoS2, MoSe2, WS2, and WSe2, respectively. The negative values of this coefficients imply a narrowing of the fundamental band gap with the increase in hydrostatic pressure and a semiconductor to metal transition for MoS2, MoSe2, WS2, and WSe2, crystals at around 140, 180, 190, and 240 kbar, respectively. PMID:27215469

  2. Pressure coefficients for direct optical transitions in MoS2, MoSe2, WS2, and WSe2 crystals and semiconductor to metal transitions

    PubMed Central

    Dybała, F.; Polak, M. P.; Kopaczek, J.; Scharoch, P.; Wu, K.; Tongay, S.; Kudrawiec, R.

    2016-01-01

    The electronic band structure of MoS2, MoSe2, WS2, and WSe2, crystals has been studied at various hydrostatic pressures experimentally by photoreflectance (PR) spectroscopy and theoretically within the density functional theory (DFT). In the PR spectra direct optical transitions (A and B) have been clearly observed and pressure coefficients have been determined for these transitions to be: αA = 2.0 ± 0.1 and αB = 3.6 ± 0.1 meV/kbar for MoS2, αA = 2.3 ± 0.1 and αB = 4.0 ± 0.1 meV/kbar for MoSe2, αA = 2.6 ± 0.1 and αB = 4.1 ± 0.1 meV/kbar for WS2, αA = 3.4 ± 0.1 and αB = 5.0 ± 0.5 meV/kbar for WSe2. It has been found that these coefficients are in an excellent agreement with theoretical predictions. In addition, a comparative study of different computational DFT approaches has been performed and analyzed. For indirect gap the pressure coefficient have been determined theoretically to be −7.9, −5.51, −6.11, and −3.79, meV/kbar for MoS2, MoSe2, WS2, and WSe2, respectively. The negative values of this coefficients imply a narrowing of the fundamental band gap with the increase in hydrostatic pressure and a semiconductor to metal transition for MoS2, MoSe2, WS2, and WSe2, crystals at around 140, 180, 190, and 240 kbar, respectively. PMID:27215469

  3. Pressure coefficients for direct optical transitions in MoS2, MoSe2, WS2, and WSe2 crystals and semiconductor to metal transitions

    NASA Astrophysics Data System (ADS)

    Dybała, F.; Polak, M. P.; Kopaczek, J.; Scharoch, P.; Wu, K.; Tongay, S.; Kudrawiec, R.

    2016-05-01

    The electronic band structure of MoS2, MoSe2, WS2, and WSe2, crystals has been studied at various hydrostatic pressures experimentally by photoreflectance (PR) spectroscopy and theoretically within the density functional theory (DFT). In the PR spectra direct optical transitions (A and B) have been clearly observed and pressure coefficients have been determined for these transitions to be: αA = 2.0 ± 0.1 and αB = 3.6 ± 0.1 meV/kbar for MoS2, αA = 2.3 ± 0.1 and αB = 4.0 ± 0.1 meV/kbar for MoSe2, αA = 2.6 ± 0.1 and αB = 4.1 ± 0.1 meV/kbar for WS2, αA = 3.4 ± 0.1 and αB = 5.0 ± 0.5 meV/kbar for WSe2. It has been found that these coefficients are in an excellent agreement with theoretical predictions. In addition, a comparative study of different computational DFT approaches has been performed and analyzed. For indirect gap the pressure coefficient have been determined theoretically to be ‑7.9, ‑5.51, ‑6.11, and ‑3.79, meV/kbar for MoS2, MoSe2, WS2, and WSe2, respectively. The negative values of this coefficients imply a narrowing of the fundamental band gap with the increase in hydrostatic pressure and a semiconductor to metal transition for MoS2, MoSe2, WS2, and WSe2, crystals at around 140, 180, 190, and 240 kbar, respectively.

  4. Order and disorder in the local and long-range structure of the spin-glass pyrochlore, Tb{sub 2}Mo{sub 2}O{sub 7}

    SciTech Connect

    Jiang, Yu; Huq, Ashfia; Booth, Corwin H.; Ehlers, Georg; Greedan, John E.; Gardner, Jason S.

    2011-02-11

    To understand the origin of the spin-glass state in molybdate pyrochlores, the structure of Tb{sub 2}Mo{sub 2}O{sub 7} is investigated using two techniques: the long-range lattice structure was measured using neutron powder diffraction (NPD), and local structure information was obtained from the extended x-ray absorption fine structure (EXAFS) technique. While the long-range structure appears generally well ordered, enhanced mean-squared site displacements on the O(1) site and the lack of temperature dependence of the strongly anisotropic displacement parameters for both the Mo and O(1) sites indicate some disorder exists. Likewise, the local structure measurements indicate some Mo-Mo and Tb-O(1) nearest-neighbor disorder exists, similar to that found in the related spin-glass pyrochlore, Y{sub 2}Mo{sub 2}O{sub 7}. Although the freezing temperature in Tb{sub 2}Mo{sub 2}O{sub 7}, 25 K, is slightly higher than in Y{sub 2}Mo{sub 2}O{sub 7}, 22 K, the degree of local pair distance disorder is actually less in Tb{sub 2}Mo{sub 2}O{sub 7}. This apparent contradiction is considered in light of the interactions involved in the freezing process.

  5. Characterization of MODIS SD screen vignetting function using observations from spacecraft yaw maneuvers

    NASA Astrophysics Data System (ADS)

    Wang, Zhipeng; Xiong, Xiaoxiong

    2009-08-01

    The MODIS reflective solar bands (RSB) include both the low-gain and high-gain spectral bands depending on their specific applications. MODIS RSBs are calibrated on-orbit by an on-board solar diffuser. In order to avoid detector response saturation when calibrating the high-gain bands, an optional attenuation screen, made of a metal plate with pinhole arrays, is placed in front of the SD panel. Since no pre-launch system-level characterization was made for the SD screen (SDS) vignetting function (VF), a series of spacecraft (Terra and Aqua) yaw maneuvers were carried out to perform on-orbit characterization of the VF. Assuming that the low-gain bands and the high-gain bands have the same VF, the current VF was derived from yaw observations using the MODIS low-gain bands through taking the ratio of their SD responses with and without the SDS in place. In this study, we attempt to characterize the SDS VF directly using detector responses of individual high-gain bands with the SDS in place only. The corresponding SD responses without the SDS, not available from measurements due to saturation, are calculated using detector gains, the SD bi-directional reflectance factor (BRF), and the view geometry that matches the yaw observations with the SDS in place. Results and discussions are focused on the band dependent and detector dependent features of the SDS VF, and their potential impact on the RSB calibration.

  6. The qSD12 Locus Controls Offspring Tissue-Imposed Seed Dormancy in Rice

    PubMed Central

    Gu, Xing-You; Turnipseed, E. Brent; Foley, Michael E.

    2008-01-01

    Seed component structures were grouped into maternal and offspring (embryo and endosperm) tissues to characterize a dormancy quantitative trait locus (QTL) for tissue-specific function using a marker-assisted genetic approach. The approach was devised to test if genotypic/allelic frequencies of a marker tightly linked to the QTL deviate from Mendelian expectations in germinated and nongerminated subpopulations derived from a segregation population of partially after-ripened seeds and was applied to the dormancy QTL qSD12 and qSD7-1 in a nearly isogenic background of rice. Experimental results unambiguously demonstrated that qSD12 functions in the offspring tissue(s) and suggested that qSD7-1 may control dormancy through the maternal tissues. These experiments also provide the first solid evidence that an offspring tissue-imposed dormancy gene contributes to the segregation distortion in a mapping population developed from partially after-ripened seeds and, in part, to the germination heterogeneity of seeds from hybrid plants. Offspring and maternal tissue-imposed dormancy genes express in very early and late stages of the life cycle, respectively, and interact to provide the species with complementary adaptation strategies. The qSD12 locus was narrowed to the region of ∼600 kbp on a high-resolution map to facilitate cloning and marker-assisted selection of the major dormancy gene. PMID:18711220

  7. The Mass of the sdB Primary of the Binary HS 2333+3927

    NASA Astrophysics Data System (ADS)

    Heber, U.; Drechsel, H.; Karl, C.; Østensen, R.; Folkes, S.; Napiwotzki, R.; Altmann, M.; Cordes, O.; Solheim, J.-E.; Voss, B.; Koester, D.

    2005-07-01

    Short period sdB binaries with cool companions are crucial to understand pre-CV evolution, because they will evolve into cataclysmic variables, when the sdB will have left the extended horizontal branch. Recently we discovered the sixth such system, HS 2333+3927, consisting of an sdB star and an M dwarf (period: 0.172 d) with a very strong reflection effect, but no eclipses. The reflection is stronger than in any of the other similar systems which renders a quantitative spectral analysis very difficult because the Balmer line profiles may be disturbed by the reflected light. A spectroscopic analysis results in {Teff} = 36 500 K, log{g} = 5.70, and log (nHe/nH) = -2.15. Mass-radius relations were derived from the results of the analysis of light and radial-velocity curves. Comparison with the mass-radius relation derived from the surface gravity of the sdB star favours a rather low mass of 0.38 M⊙ for the primary. The mass of the companion is 0.29 M⊙. HS 2333+3927 is the only known sdB+dM system with a period above the CV period gap.

  8. Hypertension during chronic exposure to cold: Comparison between Sprague Dawley (SD) and Long Evans (LE) strains

    SciTech Connect

    Riesselmann, A.; Baron, A.; Fregly, M.J. )

    1991-03-11

    Hypertension accompanies chronic exposure of SD rats to cold (5-6C), including elevation of systolic, diastolic, and mean blood pressures and cardiac hypertrophy. The renin-angiotensin system may play an important role. Earlier studies suggested that the LE strain may have a decrease in angiotensin I converting enzyme (ACE) activity. Measurement of ACE activity in plasmas of SE and LE strains revealed that basal activity of ACE in the plasma of the LE strain was significantly less than that of the SD strain. A second study was carried out in which both strains were exposed to cold for 7 weeks. There were clear differences between strains. Rats of the SD strain had a significant elevation in their blood pressure; a significantly increased urinary output of norepinephrine (NE) and epinephrine (E); and significant increases in weights of heart, kidneys, adrenals, and brown adipose tissue (IBAT) compared to their controls maintained at 26C. In contrast, rats of the LE strain were less responsive to cold in that blood pressure failed to rise as sharply and to attain as high a level; NE and E outputs, as well as weights of heart and IBAT were significantly less than those of rats of the cold-treated SD strain. Thus, the lower ACE activity in plasma of LE strain, as well as a reduced secretion of catecholamines, may protect these rats against the rise of blood pressure characteristically observed when rats of the SD strain are exposed to cold.

  9. Lattice dynamics in austenitic stainless steels Fe 18Cr 12Ni 2Mo and Fe 18Cr 16Ni 10Mn

    NASA Astrophysics Data System (ADS)

    Rajevac, V.; Hoelzel, M.; Danilkin, S. A.; Hoser, A.; Fuess, H.

    2004-04-01

    Phonon dispersion curves of austenitic stainless steels Fe-18Cr-16Ni-10Mn and Fe-18Cr-12Ni-2Mo have been measured by triple-axis neutron spectroscopy. The data were analysed using Born-von Karman interactions as well as calculations including the contribution of conduction electrons on the lattice dynamics. An appropriate description of the experimental data was obtained by taking into account two-neighbour shells plus the contribution of the electron gas. The elastic constants and moduli obtained are close to reported results by ultrasonic studies on polycrystalline samples. The phonon densities of states in both systems calculated from the dispersion curves agree well with results obtained by time-of-flight neutron spectroscopy on polycrystalline samples. The Debye temperature THgr(T) shows a minimum around 40 K, similar to copper and nickel.

  10. Studies of EPR parameters for Mn5+-doped Ca2(MO4)Cl (M = P, As, V) crystals from a two-mechanism model

    NASA Astrophysics Data System (ADS)

    Wu, Xiao-Xuan; Yu, Xin-Peng; Zheng, Wen-Chen

    2014-12-01

    The EPR parameters (zero-field splitting D and g-factors g//, g⊥) of Mn5+-doped solid state laser materials Ca2(MO4)Cl (M = P, As, V) are calculated from the complete high-order perturbation formulas of EPR parameters based on the two-mechanism model for 3d2 ions in a approximately tetragonal tetrahedron. The model includes the contributions from both the crystal-field (CF) mechanism and the charge-transfer (CT) mechanism (the latter is neglected in crystal field theory). The calculated results suggest that the contribution to EPR parameters due to CT mechanism is important. So, in the cases of high valence state 3dn ions in crystals, the reasonable explanation of EPR parameters should take both CF and CT mechanisms into account.

  11. Semi-empirical and ab initio DFT modeling of the spin-Hamiltonian parameters for Fe6+: K2MO4 (M = S, Cr, Se)

    NASA Astrophysics Data System (ADS)

    Avram, N. M.; Brik, M. G.; Andreici, E.-L.

    2014-09-01

    In this paper we calculated the spin-Hamiltonian parameters (g factors {{g}||}, {{g}\\bot } and zero field splitting parameter D) for Fe6+ ions doped in K2MO4 (M = S, Cr, Se) crystals, taking into account the actual site symmetry of the Fe6+ impurity ion. The suggested method is based on the successful application of two different approaches: the crystal field theory (CFT) and density functional based (DFT). Within the CFT model we used the cluster approach and the perturbation theory method, based on the crystal field parameters, which were calculated in the superposition model. Within the DFT approach the calculations were done at the self-consistent field (SCF) by solving the coupled perturbed SCF equations. Comparison with experimental data shows that the obtained results are quite satisfactory, which proves applicability of the suggested calculating technique.

  12. Optical constants and dynamic conductivities of single layer MoS{sub 2}, MoSe{sub 2}, and WSe{sub 2}

    SciTech Connect

    Morozov, Yurii V.; Kuno, Masaru

    2015-08-24

    The complex optical constants of single layer MoS{sub 2}, MoSe{sub 2}, and WSe{sub 2} transition metal dichalcogenides (TMDCs) have been measured using concerted frequency-dependent transmittance and reflectance measurements. Absolute absorptivities as well as complex refractive indices and dielectric permittivities have been extracted. Comparisons to associated bulk responses reveal differences due to increased electron-hole interactions in single layer TMDCs. In parallel, corresponding complex optical conductivities (σ) have been determined. For MoS{sub 2}, extracted σ-values qualitatively agree with recent theoretical estimates. Significant differences exist, though, between experiment and theory regarding the imaginary part of σ. In all cases, the current approach distinguishes itself to other measurements of single layer TMDC optical constants in which it does not rely on Kramers-Kronig transformations of reflectance data.

  13. Photosensitivity of ZnO/CdS/Cu(In,Ga)Se{sub 2}/Mo thin-film solar cells fabricated on various substrates

    SciTech Connect

    Rud, V. Yu.; Rud, Yu. V.; Gremenok, V. F.; Terukov, E. I.; Bairamov, B. Kh.; Song, Y. W.

    2012-02-15

    The results of measuring the first spectra of relative quantum efficiency for photoconversion in thin-film ZnO/CdS/Cu(In,Ga)Se{sub 2}/Mo solar cells fabricated on rigid (glass) and flexible (polyimide) substrates are reported. The character of interband transitions has been studied and the values of the band gap for direct and indirect transitions in thin Cu(In,Ga)Se{sub 2} films are determined. It is found that a shift of the maximal photosensitivity for the obtained solar cells to shorter wavelengths is observed as rigid substrates are replaced by flexible ones. It is concluded that thin-film Cu(In,Ga)Se{sub 2} structures can be used as broad-band photoconverters of solar radiation.

  14. NANOELECTRONICS. Epitaxial growth of a monolayer WSe2-MoS2 lateral p-n junction with an atomically sharp interface.

    PubMed

    Li, Ming-Yang; Shi, Yumeng; Cheng, Chia-Chin; Lu, Li-Syuan; Lin, Yung-Chang; Tang, Hao-Lin; Tsai, Meng-Lin; Chu, Chih-Wei; Wei, Kung-Hwa; He, Jr-Hau; Chang, Wen-Hao; Suenaga, Kazu; Li, Lain-Jong

    2015-07-31

    Two-dimensional transition metal dichalcogenides (TMDCs) such as molybdenum sulfide MoS2 and tungsten sulfide WSe2 have potential applications in electronics because they exhibit high on-off current ratios and distinctive electro-optical properties. Spatially connected TMDC lateral heterojunctions are key components for constructing monolayer p-n rectifying diodes, light-emitting diodes, photovoltaic devices, and bipolar junction transistors. However, such structures are not readily prepared via the layer-stacking techniques, and direct growth favors the thermodynamically preferred TMDC alloys. We report the two-step epitaxial growth of lateral WSe2-MoS2 heterojunction, where the edge of WSe2 induces the epitaxial MoS2 growth despite a large lattice mismatch. The epitaxial growth process offers a controllable method to obtain lateral heterojunction with an atomically sharp interface. PMID:26228146

  15. High density of (pseudo) periodic twin-grain boundaries in molecular beam epitaxy-grown van der Waals heterostructure: MoTe2/MoS2

    NASA Astrophysics Data System (ADS)

    Diaz, Horacio Coy; Ma, Yujing; Chaghi, Redhouane; Batzill, Matthias

    2016-05-01

    Growth of transition metal dichalcogenide heterostructures by molecular beam epitaxy (MBE) promises synthesis of artificial van der Waals materials with controllable layer compositions and separations. Here, we show that MBE growth of 2H-MoTe2 monolayers on MoS2 substrates results in a high density of mirror-twins within the films. The grain boundaries are tellurium deficient, suggesting that Te-deficiency during growth causes their formation. Scanning tunneling microscopy and spectroscopy reveal that the grain boundaries arrange in a pseudo periodic "wagon wheel" pattern with only ˜2.6 nm repetition length. Defect states from these domain boundaries fill the band gap and thus give the monolayer an almost metallic property. The band gap states pin the Fermi-level in MoTe2 and thus determine the band-alignment in the MoTe2/MoS2 interface.

  16. Agonist-bound structure of the human P2Y12 receptor

    PubMed Central

    Zhang, Jin; Zhang, Kaihua; Gao, Zhan-Guo; Paoletta, Silvia; Zhang, Dandan; Han, Gye Won; Li, Tingting; Ma, Limin; Zhang, Wenru; Müller, Christa E.; Yang, Huaiyu; Jiang, Hualiang; Cherezov, Vadim; Katritch, Vsevolod; Jacobson, Kenneth A.; Stevens, Raymond C.; Wu, Beili; Zhao, Qiang

    2014-01-01

    The P2Y12 receptor (P2Y12R), one of eight members of the P2YR family expressed in humans, has been identified as one of the most prominent clinical drug targets for inhibition of platelet aggregation. Consequently, extensive mutagenesis and modeling studies of the P2Y12R have revealed many aspects of agonist/antagonist binding1-4. However, the details of agonist and antagonist recognition and function at the P2Y12R remain poorly understood at the molecular level. Here, we report the structures of the human P2Y12R in complex with a full agonist 2-methylthio-adenosine-5′-diphosphate (2MeSADP, a close analogue of endogenous agonist ADP) at 2.5 Å resolution, and the corresponding ATP derivative 2-methylthio-adenosine-5′-triphosphate (2MeSATP) at 3.1 Å resolution. Analysis of these structures, together with the structure of the P2Y12R with antagonist ethyl 6-(4-((benzylsulfonyl)carbamoyl)piperidin-1-yl)-5-cyano-2-methylnicotinate (AZD1283)5, reveals dramatic conformational changes between nucleotide and non-nucleotide ligand complexes in the extracellular regions, providing the first insight into a different ligand binding landscape in the δ-group of class A G protein-coupled receptors (GPCRs). Agonist and non-nucleotide antagonist adopt different orientations in the P2Y12R, with only partially overlapped binding pockets. The agonist-bound P2Y12R structure answers long-standing ambiguities surrounding P2Y12R-agonist recognition, and reveals interactions with several residues that had not been reported to be involved in agonist binding. As a first example of a GPCR where agonist access to the binding pocket requires large scale rearrangements in the highly malleable extracellular region, the structural studies therefore will provide invaluable insight into the pharmacology and mechanisms of action of agonists and different classes of antagonists for the P2Y12R and potentially for other closely related P2YRs. PMID:24784220

  17. Self-powdering and nonlinear optical domain structures in ferroelastic beta'-Gd{sub 2}(MoO{sub 4}){sub 3} crystals formed in glass

    SciTech Connect

    Tsukada, Y.; Honma, T.; Komatsu, T.

    2009-08-15

    Ferroelastic beta'-Gd{sub 2}(MoO{sub 4}){sub 3}, (GMO), crystals are formed through the crystallization of 21.25Gd{sub 2}O{sub 3}-63.75MoO{sub 3}-15B{sub 2}O{sub 3} glass (mol%), and two scientific curious phenomena are observed. (1) GMO crystals formed in the crystallization break into small pieces with a triangular prism or pyramid shape having a length of 50-500 {mu}m spontaneously during the crystallizations in the inside of an electric furnace, not during the cooling in air after the crystallization. This phenomenon is called 'self-powdering phenomenon during crystallization' in this paper. (2) Each self-powdered GMO crystal grain shows a periodic domain structure with different refractive indices, and a spatially periodic second harmonic generation (SHG) depending on the domain structure is observed. It is proposed from polarized micro-Raman scattering spectra and the azimuthal dependence of second harmonic intensities that GMO crystals are oriented in each crystal grain and the orientation of (MoO{sub 4}){sup 2-} tetrahedra in GMO crystals changes periodically due to spontaneous strains in ferroelastic GMO crystals. - Graphical abstract: This figure shows the polarized optical photograph at room temperature for a particle (piece) obtained by a heat treatment of the glass at 590 deg. C for 2 h in an electric furnace in air. This particle was obtained through the self-powdering behavior in the crystallization of glass. The periodic domain structure is observed. Ferroelastic beta'-Gd{sub 2}(MoO{sub 4}){sub 3} crystals are formed in the particle, and second harmonic generations are detected, depending on the domain structure.

  18. Direct optical transitions at K- and H-point of Brillouin zone in bulk MoS2, MoSe2, WS2, and WSe2

    NASA Astrophysics Data System (ADS)

    Kopaczek, J.; Polak, M. P.; Scharoch, P.; Wu, K.; Chen, B.; Tongay, S.; Kudrawiec, R.

    2016-06-01

    Modulated reflectance (contactless electroreflectance (CER), photoreflectance (PR), and piezoreflectance (PzR)) has been applied to study direct optical transitions in bulk MoS2, MoSe2, WS2, and WSe2. In order to interpret optical transitions observed in CER, PR, and PzR spectra, the electronic band structure for the four crystals has been calculated from the first principles within the density functional theory for various points of Brillouin zone including K and H points. It is clearly shown that the electronic band structure at H point of Brillouin zone is very symmetric and similar to the electronic band structure at K point, and therefore, direct optical transitions at H point should be expected in modulated reflectance spectra besides the direct optical transitions at the K point of Brillouin zone. This prediction is confirmed by experimental studies of the electronic band structure of MoS2, MoSe2, WS2, and WSe2 crystals by CER, PR, and PzR spectroscopy, i.e., techniques which are very sensitive to critical points of Brillouin zone. For the four crystals besides the A transition at K point, an AH transition at H point has been observed in CER, PR, and PzR spectra a few tens of meV above the A transition. The spectral difference between A and AH transition has been found to be in a very good agreement with theoretical predictions. The second transition at the H point of Brillouin zone (BH transition) overlaps spectrally with the B transition at K point because of small energy differences in the valence (conduction) band positions at H and K points. Therefore, an extra resonance which could be related to the BH transition is not resolved in modulated reflectance spectra at room temperature for the four crystals.

  19. Geobacter sp. SD-1 with enhanced electrochemical activity in high-salt concentration solutions.

    PubMed

    Sun, Dan; Call, Douglas; Wang, Aijie; Cheng, Shaoan; Logan, Bruce E

    2014-12-01

    An isolate, designated strain SD-1, was obtained from a biofilm dominated by Geobacter sulfurreducens in a microbial fuel cell. The electrochemical activity of strain SD-1 was compared with type strains, G. sulfurreducens PCA and Geobacter metallireducens GS-15, and a mixed culture in microbial electrolysis cells. SD-1 produced a maximum current density of 290 ± 29 A m−3 in a high-concentration phosphate buffer solution (PBS-H, 200 mM). This current density was significantly higher than that produced by the mixed culture (189 ± 44 A m−3) or the type strains (< 70 A m−3). In a highly saline water (SW; 50 mM PBS and 650 mM NaCl), current by SD-1 (158 ± 4 A m−3) was reduced by 28% compared with 50 mM PBS (220 ± 4 A m−3), but it was still higher than that of the mixed culture (147 ± 19 A m−3), and strains PCA and GS-15 did not produce any current. Electrochemical tests showed that the improved performance of SD-1 was due to its lower charge transfer resistance and more negative potentials produced at higher current densities. These results show that the electrochemical activity of SD-1 was significantly different than other Geobacter strains and mixed cultures in terms of its salt tolerance. PMID:25756125

  20. A New sdO+dM Binary with Extreme Eclipses and Reflection Effect

    NASA Astrophysics Data System (ADS)

    Derekas, A.; Németh, P.; Southworth, J.; Borkovits, T.; Sárneczky, K.; Pál, A.; Csák, B.; Garcia-Alvarez, D.; Maxted, P. F. L.; Kiss, L. L.; Vida, K.; Szabó, Gy. M.; Kriskovics, L.

    2015-08-01

    We report the discovery of a new totally eclipsing binary (R.A. = {06}{{h}}{40}{{m}}{29}{{s}}11; decl. = +38°56‧52″2 J = 2000.0; Rmax = 17.2 mag) with an sdO primary and a strongly irradiated red dwarf companion. It has an orbital period of Porb = 0.187284394(11) day and an optical eclipse depth in excess of 5 mag. We obtained 2 low-resolution classification spectra with GTC/OSIRIS and 10 medium-resolution spectra with WHT/ISIS to constrain the properties of the binary members. The spectra are dominated by H Balmer and He ii absorption lines from the sdO star, and phase-dependent emission lines from the irradiated companion. A combined spectroscopic and light curve analysis implies a hot subdwarf temperature of Teff(spec) = 55,000 ± 3000 K, surface gravity of log g (phot) = 6.2 ± 0.04 (cgs), and a He abundance of {log}(n{He}/n{{H}})=-2.24+/- 0.40. The hot sdO star irradiates the red dwarf companion, heating its substellar point to about 22,500 K. Surface parameters for the companion are difficult to constrain from the currently available data: the most remarkable features are the strong H Balmer and C ii-iii lines in emission. Radial velocity estimates are consistent with the sdO+dM classification. The photometric data do not show any indication of sdO pulsations with amplitudes greater than 7 mmag, and Hα-filter images do not provide evidence for the presence of a planetary nebula associated with the sdO star.

  1. Effect of P2Y12 inhibitors on inflammation and immunity.

    PubMed

    Thomas, Mark R; Storey, Robert F

    2015-08-31

    Platelet P2Y12 inhibitors form a major part of the treatment strategy for patients with acute coronary syndromes (ACS) due to the importance of the platelet P2Y12 receptor in mediating the pathophysiology of arterial thrombosis. It has been increasingly recognised that platelets also have a critical role in inflammation and immune responses. P2Y12 inhibitors reduce platelet release of pro-inflammatory α-granule contents and the formation of pro-inflammatory platelet-leukocyte aggregates. These are important mediators of inflammation in a variety of different contexts. Clinical evidence shows that P2Y12 inhibition by clopidogrel is associated with a reduction in platelet-related mediators of inflammation, such as soluble P-selectin and CD40L, following atherothrombosis. Clopidogrel in addition to aspirin, compared to aspirin alone, also reduces markers of systemic inflammation such as tumour necrosis factor (TNF) α and C-reactive protein (CRP) following ACS. The more potent thienopyridine P2Y12 inhibitor, prasugrel, has been shown to decrease platelet P-selectin expression and platelet-leukocyte aggregate formation compared to clopidogrel. The PLATO study suggested that the novel P2Y12 inhibitor ticagrelor might improve clinical outcomes from pulmonary infections and sepsis compared to clopidogrel in patients with ACS. Ticagrelor is a more potent P2Y12 inhibitor than clopidogrel and also inhibits cellular adenosine uptake via equilibrative nucleoside transporter (ENT) 1, whereas clopidogrel does not. Further examination of the involvement of these mechanisms in inflammation and immunity is therefore warranted. PMID:26156883

  2. The Ratio of ADP- to TRAP-Induced Platelet Aggregation Quantifies P2Y12-Dependent Platelet Inhibition Independently of the Platelet Count

    PubMed Central

    Olivier, Christoph B.; Meyer, Melanie; Bauer, Hans; Schnabel, Katharina; Weik, Patrick; Zhou, Qian; Bode, Christoph; Moser, Martin; Diehl, Philipp

    2016-01-01

    Objective This study aimed to assess the association of clinical factors with P2Y12-dependent platelet inhibition as monitored by the ratio of ADP- to TRAP-induced platelet aggregation and conventional ADP-induced aggregation, respectively. Background Controversial findings to identify and overcome high platelet reactivity (HPR) after coronary stent-implantation and to improve clinical outcome by tailored anti-platelet therapy exist. Monitoring anti-platelet therapy ex vivo underlies several confounding parameters causing that ex vivo platelet aggregation might not reflect in vivo platelet inhibition. Methods In a single centre observational study, multiple electrode aggregometry was performed in whole blood of patients after recent coronary stent-implantation. Relative ADP-induced aggregation (r-ADP-agg) was defined as the ratio of ADP- to TRAP- induced aggregation reflecting the individual degree of P2Y12-mediated platelet reactivity. Results Platelet aggregation was assessed in 359 patients. Means (± SD) of TRAP-, ADP-induced aggregation and r-ADP-agg were 794 ± 239 AU*min, 297 ± 153 AU*min and 37 ± 14%, respectively. While ADP- and TRAP-induced platelet aggregation correlated significantly with platelet count (ADP: r = 0.302; p<0.001; TRAP: r = 0.509 p<0.001), r-ADP-agg values did not (r = -0.003; p = 0.960). These findings were unaltered in multivariate analyses adjusting for a range of factors potentially influencing platelet aggregation. The presence of an acute coronary syndrome and body weight were found to correlate with both ADP-induced platelet aggregation and r-ADP-agg. Conclusion The ratio of ADP- to TRAP-induced platelet aggregation quantifies P2Y12-dependent platelet inhibition independently of the platelet count in contrast to conventional ADP-induced aggregation. Furthermore, r-ADP-agg was associated with the presence of an acute coronary syndrome and body weight as well as ADP-induced aggregation. Thus, the r-ADP-agg is a more valid

  3. Shell-model study for neutron-rich sd-shell nuclei

    SciTech Connect

    Kaneko, Kazunari; Sun Yang; Mizusaki, Takahiro; Hasegawa, Munetake

    2011-01-15

    The microscopic structure of neutron-rich sd-shell nuclei is investigated by using the spherical-shell model in the sd-pf valence space with the extended pairing plus quadrupole-quadrupole forces accompanied by the monopole interaction (EPQQM). The calculation reproduces systematically the known energy levels for even-even and odd-mass nuclei including the recent data for {sup 43}S, {sup 46}S, and {sup 47}Ar. In particular, the erosion of the N=28 shell closure in {sup 42}Si can be explained. Our EPQQM results are compared with other shell-model calculations with the SDPF-NR and SDPF-U effective interactions.

  4. Epoxy encapsulation of the Cernox™ SD thermometer for measuring the temperature of surfaces in liquid helium

    NASA Astrophysics Data System (ADS)

    Dhuley, R. C.; Van Sciver, S. W.

    2016-07-01

    We describe a procedure to pot a Cernox™ thermometer with the SD package in Stycast epoxy. The potting adapts the thermometer for measuring the temperature of a surface immersed in liquid helium (LHe) and other cryogens. The technique thermally insulates the sensor chip from the cryogen while preserving the surface mounting capability of the SD package. The potting introduced <1% shift in the resistance, <0.5% shift in the calibration at 4.2 K and 77 K, and provided repeatable measurements during thermal cycles between room temperature and 4.2 K.

  5. Initial results from the Solar Dynamic (SD) Ground Test Demonstration (GTD) project at NASA Lewis

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Boyle, Robert V.

    1995-01-01

    A government/industry team designed, built, and tested a 2 kWe solar dynamic space power system in a large thermal/vacuum facility with a simulated sun at the NASA Lewis Research Center. The Lewis facility provides an accurate simulation of temperatures, high vacuum, and solar flux as encountered in low earth orbit. This paper reviews the goals and status of the Solar Dynamic (SD) Ground Test Demonstration (GTD) program and describes the initial testing, including both operational and performance data. This SD technology has the potential as a future power source for the International Space Station Alpha.

  6. P2Y6 Receptor Potentiates Pro-Inflammatory Responses in Macrophages and Exhibits Differential Roles in Atherosclerotic Lesion Development

    PubMed Central

    Garcia, Ricardo A.; Yan, Mujing; Search, Debra; Zhang, Rongan; Carson, Nancy L.; Ryan, Carol S.; Smith-Monroy, Constance; Zheng, Joanna; Chen, Jian; Kong, Yan; Tang, Huaping; Hellings, Samuel E.; Wardwell-Swanson, Judith; Dinchuk, Joseph E.; Psaltis, George C.; Gordon, David A.; Glunz, Peter W.; Gargalovic, Peter S.

    2014-01-01

    Background P2Y6, a purinergic receptor for UDP, is enriched in atherosclerotic lesions and is implicated in pro-inflammatory responses of key vascular cell types and macrophages. Evidence for its involvement in atherogenesis, however, has been lacking. Here we use cell-based studies and three murine models of atherogenesis to evaluate the impact of P2Y6 deficiency on atherosclerosis. Methodology/Principal Findings Cell-based studies in 1321N1 astrocytoma cells, which lack functional P2Y6 receptors, showed that exogenous expression of P2Y6 induces a robust, receptor- and agonist-dependent secretion of inflammatory mediators IL-8, IL-6, MCP-1 and GRO1. P2Y6-mediated inflammatory responses were also observed, albeit to a lesser extent, in macrophages endogenously expressing P2Y6 and in acute peritonitis models of inflammation. To evaluate the role of P2Y6 in atherosclerotic lesion development, we used P2Y6-deficient mice in three mouse models of atherosclerosis. A 43% reduction in aortic arch plaque was observed in high fat-fed LDLR knockout mice lacking P2Y6 receptors in bone marrow-derived cells. In contrast, no effect on lesion development was observed in fat-fed whole body P2Y6xLDLR double knockout mice. Interestingly, in a model of enhanced vascular inflammation using angiotensin II, P2Y6 deficiency enhanced formation of aneurysms and exhibited a trend towards increased atherosclerosis in the aorta of LDLR knockout mice. Conclusions P2Y6 receptor augments pro-inflammatory responses in macrophages and exhibits a pro-atherogenic role in hematopoietic cells. However, the overall impact of whole body P2Y6 deficiency on atherosclerosis appears to be modest and could reflect additional roles of P2Y6 in vascular disease pathophysiologies, such as aneurysm formation. PMID:25360548

  7. Intrinsic Josephson properties in Pb1-ySr2Y1-xCaxCu2+yO7+δ epitaxial films

    NASA Astrophysics Data System (ADS)

    Komori, Sachio; Kakeya, Itsuhiro

    2014-12-01

    We report the first observation of intrinsic Josephson junction (IJJ) characteristics in the Pb1-ySr2Y1-xCaxCu2+yO7+δ (Pb1212) epitaxial film. Pb1212 epitaxial film has been grown on SrTiO3 (100) substrates by a two-step growth technique. A small mesa structure (S = 4μm2) has been fabricated on a film surface using a standard photolithography and an Ar ion milling technique. The superconducting transition temperature of the IJJ is 43 K. At 4.2 K, the value of Jc (the critical current density) is 2.2 kA/cm2. The depth of the hysteresis defined as α = (Jc+Jr)/ Jc is 0.89, where Jr is the return current density. The temperature dependence of Jc shows good agreement with Ambegaokar-Baratoff theory.

  8. Moessbauer studies in Zn(2+)0.3 Mn(2+)0.7 Mn(3+) (2-y) Fe(3+) (2-y) O4

    NASA Technical Reports Server (NTRS)

    Gupta, R. G.; Mendiratta, R. G.; Escue, W. T.

    1975-01-01

    The Mossbauer effect has proven to be effective in the study of nuclear hyperfine interactions. Ferrite systems having the formula (Zn(2+)0.3)(Mn(2+)0.7)(Mn(3+)y)(Fe(3+)2-y)(O4) were prepared and studied. These systems can be interpreted as mangacese-doped zinc and a part of iron ions. A systematic study of these systems is presented to promote an understanding of their microstructure for which various theories were proposed.

  9. P2Y2 and Gq/G11 control blood pressure by mediating endothelial mechanotransduction

    PubMed Central

    Wang, ShengPeng; Iring, András; Strilic, Boris; Albarrán Juárez, Julián; Kaur, Harmandeep; Troidl, Kerstin; Tonack, Sarah; Burbiel, Joachim C.; Müller, Christa E.; Fleming, Ingrid; Lundberg, Jon O.; Wettschureck, Nina; Offermanns, Stefan

    2015-01-01

    Elevated blood pressure is a key risk factor for developing cardiovascular diseases. Blood pressure is largely determined by vasodilatory mediators, such as nitric oxide (NO), that are released from the endothelium in response to fluid shear stress exerted by the flowing blood. Previous work has identified several mechanotransduction signaling processes that are involved in fluid shear stress–induced endothelial effects, but how fluid shear stress initiates the response is poorly understood. Here, we evaluated human and bovine endothelial cells and found that the purinergic receptor P2Y2 and the G proteins Gq/G11 mediate fluid shear stress–induced endothelial responses, including [Ca2+]i transients, activation of the endothelial NO synthase (eNOS), phosphorylation of PECAM-1 and VEGFR-2, as well as activation of SRC and AKT. In response to fluid shear stress, endothelial cells released ATP, which activates the purinergic P2Y2 receptor. Mice with induced endothelium-specific P2Y2 or Gq/G11 deficiency lacked flow-induced vasodilation and developed hypertension that was accompanied by reduced eNOS activation. Together, our data identify P2Y2 and Gq/G11 as a critical endothelial mechanosignaling pathway that is upstream of previously described mechanotransduction processes and demonstrate that P2Y2 and Gq/G11 are required for basal endothelial NO formation, vascular tone, and blood pressure. PMID:26168216

  10. Arrestin Scaffolds NHERF1 to the P2Y12 Receptor to Regulate Receptor Internalization*

    PubMed Central

    Nisar, Shaista P.; Cunningham, Margaret; Saxena, Kunal; Pope, Robert J.; Kelly, Eamonn; Mundell, Stuart J.

    2012-01-01

    We have recently shown in a patient with mild bleeding that the PDZ-binding motif of the platelet G protein-coupled P2Y12 receptor (P2Y12R) is required for effective receptor traffic in human platelets. In this study we show for the first time that the PDZ motif-binding protein NHERF1 exerts a major role in potentiating G protein-coupled receptor (GPCR) internalization. NHERF1 interacts with the C-tail of the P2Y12R and unlike many other GPCRs, NHERF1 interaction is required for effective P2Y12R internalization. In vitro and prior to agonist stimulation P2Y12R/NHERF1 interaction requires the intact PDZ binding motif of this receptor. Interestingly on receptor stimulation NHERF1 no longer interacts directly with the receptor but instead binds to the receptor via the endocytic scaffolding protein arrestin. These findings suggest a novel model by which arrestin can serve as an adaptor to promote NHERF1 interaction with a GPCR to facilitate effective NHERF1-dependent receptor internalization. PMID:22610101

  11. Arrestin scaffolds NHERF1 to the P2Y12 receptor to regulate receptor internalization.

    PubMed

    Nisar, Shaista P; Cunningham, Margaret; Saxena, Kunal; Pope, Robert J; Kelly, Eamonn; Mundell, Stuart J

    2012-07-13

    We have recently shown in a patient with mild bleeding that the PDZ-binding motif of the platelet G protein-coupled P2Y(12) receptor (P2Y(12)R) is required for effective receptor traffic in human platelets. In this study we show for the first time that the PDZ motif-binding protein NHERF1 exerts a major role in potentiating G protein-coupled receptor (GPCR) internalization. NHERF1 interacts with the C-tail of the P2Y(12)R and unlike many other GPCRs, NHERF1 interaction is required for effective P2Y(12)R internalization. In vitro and prior to agonist stimulation P2Y(12)R/NHERF1 interaction requires the intact PDZ binding motif of this receptor. Interestingly on receptor stimulation NHERF1 no longer interacts directly with the receptor but instead binds to the receptor via the endocytic scaffolding protein arrestin. These findings suggest a novel model by which arrestin can serve as an adaptor to promote NHERF1 interaction with a GPCR to facilitate effective NHERF1-dependent receptor internalization. PMID:22610101

  12. 75 FR 31464 - Certification of the Attorney General; Shannon County, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-03

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF JUSTICE Certification of the Attorney General; Shannon County, SD In accordance with Section 8 of the Voting Rights Act, 42 U.S.C. 1973f, I hereby certify that in my judgment the appointment of federal observers is necessary to enforce the guarantees of...

  13. AmeriFlux US-SdH Nebraska SandHills Dry Valley

    SciTech Connect

    Arkebauer, Tim J.; Billesbach, Dave

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-SdH Nebraska SandHills Dry Valley. Site Description - The Nebraska SandHills Dry Valley tower is located on public land owned by the University of Nebraska-Lincoln. The site is on a research cattle ranch where grazing primarily takes place.

  14. Semi-automatic geographic atrophy segmentation for SD-OCT images

    PubMed Central

    Chen, Qiang; de Sisternes, Luis; Leng, Theodore; Zheng, Luoluo; Kutzscher, Lauren; Rubin, Daniel L.

    2013-01-01

    Geographic atrophy (GA) is a condition that is associated with retinal thinning and loss of the retinal pigment epithelium (RPE) layer. It appears in advanced stages of non-exudative age-related macular degeneration (AMD) and can lead to vision loss. We present a semi-automated GA segmentation algorithm for spectral-domain optical coherence tomography (SD-OCT) images. The method first identifies and segments a surface between the RPE and the choroid to generate retinal projection images in which the projection region is restricted to a sub-volume of the retina where the presence of GA can be identified. Subsequently, a geometric active contour model is employed to automatically detect and segment the extent of GA in the projection images. Two image data sets, consisting on 55 SD-OCT scans from twelve eyes in eight patients with GA and 56 SD-OCT scans from 56 eyes in 56 patients with GA, respectively, were utilized to qualitatively and quantitatively evaluate the proposed GA segmentation method. Experimental results suggest that the proposed algorithm can achieve high segmentation accuracy. The mean GA overlap ratios between our proposed method and outlines drawn in the SD-OCT scans, our method and outlines drawn in the fundus auto-fluorescence (FAF) images, and the commercial software (Carl Zeiss Meditec proprietary software, Cirrus version 6.0) and outlines drawn in FAF images were 72.60%, 65.88% and 59.83%, respectively. PMID:24409376

  15. 76 FR 48120 - Black Hills National Forest, Custer, SD-Mountain Pine Beetle Response Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-08

    ... Forest Service Black Hills National Forest, Custer, SD--Mountain Pine Beetle Response Project AGENCY...: This project proposes to treat areas newly infested by mountain pine beetles on approximately 325,000...-rocky-mountain-black-hills@fs.fed.us , with ``MPB Response Project'' in the subject line....

  16. Quasicontinuous spectrum of γ rays which feed and depopulate SD in ^194Pb.

    NASA Astrophysics Data System (ADS)

    McNabb, D. P.; Cizewski, J. A.; Ding, K.-Y.; Younes, W.; Khoo, T. L.; Lauritsen, T.; Archer, D. E.; Bauer, R. W.; Becker, J. A.; Bernstein, L. A.; Hauschild, K.; Clark, R. M.; Deleplanque, M. A.; Diamond, R. M.; Fallon, P.; Lee, I. Y.; Macchiavelli, A. O.; Stephens, F. S.; Kelly, W. H.

    1996-10-01

    The mechanism for decay from superdeformed (SD) to ``normal'' (ND) states in ^192Hg results in a large quasicontinuum component which can be fit by a statistical model.(R.G. Henry, et al., Phys. Rev. Lett. 73), 777 (1994). Recent experiments(M.J. Brinkman, et al., Phys. Rev. C53), R1461 (1996); T.L. Khoo, et al., Phys. Rev. Lett. 76, 1583 (1996). have also identified discrete one-step decays from SD to ND states in ^194Pb and ^194Hg which have allowed for the determination of excitation energy and spin of the second wells in these nuclei. We used the ^174Yb(^25Mg,5n) reaction at 130 MeV with a backed target and Gammasphere to study the total spectrum of γ rays in coincidence with the yrast SD band in ^194Pb. The response functions of the detectors were previously determined. The results of the preliminary analysis on the quasicontinuous γ rays which feed and depopulate the yrast SD band will be presented. This work was supported in part by the National Science Foundation and the U.S. Department of Energy.

  17. 78 FR 31430 - Proposed Establishment of Class E Airspace; Wagner, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-24

    ...This action proposes to establish Class E airspace at Wagner, SD. Controlled airspace is necessary to accommodate new Standard Instrument Approach Procedures (SIAP) at Wagner Municipal Airport. The FAA is taking this action to enhance the safety and management of Instrument Flight Rules (IFR) operations for SIAPs at the...

  18. 78 FR 25232 - Proposed Establishment of Class E Airspace; Parkston, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-30

    ...This action proposes to establish Class E airspace at Parkston, SD. Controlled airspace is necessary to accommodate new Standard Instrument Approach Procedures (SIAP) at Parkston Municipal Airport. The FAA is taking this action to enhance the safety and management of Instrument Flight Rules (IFR) operations for SIAPs at the...

  19. 78 FR 49985 - Proposed Establishment of Class E Airspace; Sisseton, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-16

    ...This action proposes to establish Class E airspace at Sisseton, SD. Controlled airspace is necessary to accommodate new Standard Instrument Approach Procedures (SIAP) at Sisseton Municipal Airport. The FAA is taking this action to enhance the safety and management of Instrument Flight Rules (IFR) operations for SIAPs at the...

  20. SD-GIS-based temporal-spatial simulation of water quality in sudden water pollution accidents

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Qin, Yu; Huang, Mingxiang; Sun, Qiang; Li, Shun; Wang, Liqiang; Yu, Chaohui

    2011-07-01

    System dynamics (SD) is well suited for studying dynamic nonlinear complex systems. In this paper, SD is applied to a rapid-onset water pollution accident using a 1-D water quality model and a conceptual GIS-SD framework is constructed to simulate the temporal-spatial changes of pollutant concentration. Based on the component GIS and the SD model, a prototype system of water quality simulation in water pollution accidents is developed. The data collected on the spot in the Songhua River water pollution accident in November 2005 were used for model parameter calibration and model validation. The results showed that: (1) the constructed model could simulate the changes of nitrobenzene concentration with time in the Songhua River water pollution accident, especially during the peak concentration and at the arrival time of peak concentration, and that the simulated values and the on-the-spot monitored values corresponded with each other well; (2) the scenario simulation could be made by adjusting parameters u (longitudinal current velocity), E (longitudinal diffusion coefficient), and k (decay rate coefficient). Such a model can provide decision makers with quantitative information to optimize related emergency response measures.

  1. High Production of Squalene Using a Newly Isolated Yeast-like Strain Pseudozyma sp. SD301.

    PubMed

    Song, Xiaojin; Wang, Xiaolong; Tan, Yanzhen; Feng, Yingang; Li, Wenli; Cui, Qiu

    2015-09-30

    A yeast-like fungus, termed strain SD301, with the ability to produce a high concentration of squalene, was isolated from Shuidong Bay, China. The nucleotide sequence analysis of the internal transcribed spacer (ITS) region of SD301 indicated the strain belonged to Pseudozyma species. The highest biomass and squalene production of SD301 were obtained when glucose and yeast extracts were used as the carbon and nitrogen sources, respectively, with a C/N ratio of 3. The optimal pH and temperature were 6 and 25 °C, with 15 g L(-1) of supplemented sea salt. The maximum squalene productivity reached 0.039 g L(-1) h(-1) in batch fermentation, while the maximum squalene yield of 2.445 g L(-1) was obtained in fed-batch fermentation. According to our knowledge, this is the highest squalene yield produced thus far using fermentation technology, and the newly isolated strain Pseudozyma sp. SD301 is a promising candidate for commercial squalene production. PMID:26350291

  2. Linear in-wavenumber optical spectrum registration in SD-OCT

    NASA Astrophysics Data System (ADS)

    Gelikonov, Grigory V.; Gelikonov, Valentin M.; Shilyagin, Pavel A.

    2012-01-01

    An efficient technique of linear in-wavenumber optical spectrum registration in SD-OCT is proposed. Methods of partial phase correction of registered optical spectrum for in-wavenumber linearization are described and investigated. The decrease sensitivity decay with depth increasing degeneration is presented. The experimental results for sample media are presented.

  3. 78 FR 24228 - Lake Andes National Wildlife Refuge Complex, Lake Andes, SD; Final Comprehensive Conservation Plan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-24

    ... review and comment following the announcement in the Federal Register on October 29, 2012 ] (77 FR 65574... Fish and Wildlife Service Lake Andes National Wildlife Refuge Complex, Lake Andes, SD; Final... conservation plan and finding of no significant impact (FONSI) for the Lake Andes National Wildlife...

  4. Exploring Stellar Evolution Models of sdB Stars using MESA

    NASA Astrophysics Data System (ADS)

    Schindler, Jan-Torge; Green, Elizabeth M.; Arnett, W. David

    2015-06-01

    Stellar evolution calculations have had great success reproducing the observed atmospheric properties of different classes of stars. Recent detections of g-mode pulsations in evolved He burning stars allow a rare comparison of their internal structure with stellar models. Asteroseismology of subdwarf B (sdB) stars suggests convective cores of 0.22-0.28 M⊙, ≳45% of the total stellar mass. Previous studies found significantly smaller convective core masses (≲0.19 M⊙) at a comparable evolutionary stage. We evolved stellar models with Modules for Experiments in Stellar Astrophysics (MESA) to explore how well the interior structures inferred from asteroseismology can be reproduced by standard algorithms. Our qualitative evolutionary paths, position in the log g-{{T}eff} diagram, and model timescales are consistent with previous results. The sdB masses from our full evolutionary sequences fall within the range of the empirical sdB mass distribution, but are nearly always lower than the median. Using standard MLT with atomic diffusion we find convective core masses of ˜0.17-0.18 M⊙, averaged over the entire sdB lifetime. We can increase the convective core sizes to be as large as those inferred from asteroseismology, but only for extreme values of the overshoot parameter (overshoot gives numerically unstable and physically unrealistic behavior at the boundary). High resolution three-dimensional simulations of turbulent convection in stars suggest that the Schwarzschild criterion for convective mixing systematically underestimates the actual extent of mixing because a boundary layer forms. Accounting for this would decrease the errors in both sdB total and convective core masses.

  5. Discovery of Potential Orthosteric and Allosteric Antagonists of P2Y1R from Chinese Herbs by Molecular Simulation Methods

    PubMed Central

    Lu, Fang; Jiang, Lu-di; Qiao, Lian-sheng; Xiang, Yu-hong

    2016-01-01

    P2Y1 receptor (P2Y1R), which belongs to G protein-coupled receptors (GPCRs), is an important target in ADP-induced platelet aggregation. The crystal structure of P2Y1R has been solved recently, which revealed orthosteric and allosteric ligand-binding sites with the details of ligand-protein binding modes. And it suggests that P2Y1R antagonists, which recognize two distinct sites, could potentially provide an efficacious and safe antithrombotic profile. In present paper, 2D similarity search, pharmacophore based screening, and molecular docking were used to explore the potential natural P2Y1R antagonists. 2D similarity search was used to classify orthosteric and allosteric antagonists of P2Y1R. Based on the result, pharmacophore models were constructed and validated by the test set. Optimal models were selected to discover potential P2Y1R antagonists of orthosteric and allosteric sites from Traditional Chinese Medicine (TCM). And the hits were filtered by Lipinski's rule. Then molecular docking was used to refine the results of pharmacophore based screening and analyze the binding mode of the hits and P2Y1R. Finally, two orthosteric and one allosteric potential compounds were obtained, which might be used in future P2Y1R antagonists design. This work provides a reliable guide for discovering natural P2Y1R antagonists acting on two distinct sites from TCM.

  6. Glycoprotein IIb/IIIa and P2Y12 Induction by Oligochitosan Accelerates Platelet Aggregation

    PubMed Central

    Halim, Ahmad Sukari; Hussein, Abdul Rahim; Ujang, Zanariah

    2014-01-01

    Platelet membrane receptor glycoprotein IIb/IIIa (gpiibiiia) is a receptor detected on platelets. Adenosine diphosphate (ADP) activates gpiibiiia and P2Y12, causing platelet aggregation and thrombus stabilization during blood loss. Chitosan biomaterials were found to promote surface induced hemostasis and were capable of activating blood coagulation cascades by enhancing platelet aggregation. Our current findings show that the activation of the gpiibiiia complex and the major ADP receptor P2Y12 is required for platelet aggregation to reach hemostasis following the adherence of various concentrations of chitosan biomaterials [7% N,O-carboxymethylchitosan (NO-CMC) with 0.45 mL collagen, 8% NO-CMC, oligochitosan (O-C), and oligochitosan 53 (O-C 53)]. We studied gpiibiiia and P2Y12 through flow cytometric analysis and western blotting techniques. The highest expression of gpiibiiia was observed with Lyostypt (74.3 ± 7.82%), followed by O-C (65.5 ± 7.17%). Lyostypt and O-C resulted in gpiibiiia expression increases of 29.2% and 13.9%, respectively, compared with blood alone. Western blot analysis revealed that only O-C 53 upregulated the expression of P2Y12 (1.12 ± 0.03-fold) compared with blood alone. Our findings suggest that the regulation of gpiibiiia and P2Y12 levels could be clinically useful to activate platelets to reach hemostasis. Further, we show that the novel oligochitosan is able to induce the increased expression of gpiibiiia and P2Y12, thus accelerating platelet aggregation in vitro. PMID:25247182

  7. LPS-induced systemic inflammation is more severe in P2Y12 null mice.

    PubMed

    Liverani, Elisabetta; Rico, Mario C; Yaratha, Laxmikausthubha; Tsygankov, Alexander Y; Kilpatrick, Laurie E; Kunapuli, Satya P

    2014-02-01

    Thienopyridines are a class of antiplatelet drugs that are metabolized in the liver to several metabolites, of which only one active metabolite can irreversibly antagonize the platelet P2Y12 receptor. Possible effects of these drugs and the role of activated platelets in inflammatory responses have also been investigated in a variety of animal models, demonstrating that thienopyridines could alter inflammation. However, it is not clear whether it is caused only by the P2Y12 antagonism or whether off-target effects of other metabolites also intervene. To address this question, we investigated P2Y12 KO mice during a LPS-induced model of systemic inflammation, and we treated these KO mice with a thienopyridine drug (clopidogrel). Contrary to the reported effects of clopidogrel, numbers of circulating WBCs and plasma levels of cytokines were increased in LPS-exposed KO mice compared with WT in this inflammation model. Moreover, both spleen and bone marrow show an increase in cell content, suggesting a role for P2Y12 in regulation of bone marrow and spleen cellular composition. Finally, the injury was more severe in the lungs of KO mice compared with WT. Interestingly, clopidogrel treatments also exerted protective effects in KO mice, suggesting off-target effects for this drug. In conclusion, the P2Y12 receptor plays an important role during LPS-induced inflammation, and this signaling pathway may be involved in regulating cell content in spleen and bone marrow during LPS systemic inflammation. Furthermore, clopidogrel may have effects that are independent of P2Y12 receptor blockade. PMID:24142066

  8. Geometric, stable and electronic properties of Aun-2Y2 (n = 3-8) clusters

    NASA Astrophysics Data System (ADS)

    Qi, Kai-Tian; Mao, Hua-Ping; Wang, Hong-Yan; Sheng, Yong

    2010-03-01

    Employing first-principles methods, based on the density function theory, and using the LANL2DZ basis sets, the ground-state geometric, the stable and the electronic properties of Aun-2Y2 clusters are investigated in this paper. Meanwhile, the differences in property among pure gold clusters, pure yttrium clusters, gold clusters doped with one yttrium atom, and gold clusters doped with two yttrium atoms are studied. We find that when gold clusters are doped by two yttrium atoms, the odd-even oscillatory behaviours of Aun-1Y and Aun disappear. The properties of Aun-2Y2 clusters are close to those of pure yttrium clusters.

  9. A hot oxidant, 3-NO2Y122 radical, unmasks conformational gating in ribonucleotide reductase.

    PubMed

    Yokoyama, Kenichi; Uhlin, Ulla; Stubbe, JoAnne

    2010-11-01

    Escherichia coli ribonucleotide reductase is an α2β2 complex that catalyzes the conversion of nucleotides to deoxynucleotides and requires a diferric-tyrosyl radical (Y(•)) cofactor to initiate catalysis. The initiation process requires long-range proton-coupled electron transfer (PCET) over 35 Å between the two subunits by a specific pathway (Y(122)(•)→W(48)→Y(356) within β to Y(731)→Y(730)→C(439) within α). The rate-limiting step in nucleotide reduction is the conformational gating of the PCET process, which masks the chemistry of radical propagation. 3-Nitrotyrosine (NO(2)Y) has recently been incorporated site-specifically in place of Y(122) in β2. The protein as isolated contained a diferric cluster but no nitrotyrosyl radical (NO(2)Y(•)) and was inactive. In the present paper we show that incubation of apo-Y(122)NO(2)Y-β2 with Fe(2+) and O(2) generates a diferric-NO(2)Y(•) that has a half-life of 40 s at 25 °C. Sequential mixing experiments, in which the cofactor is assembled to 1.2 NO(2)Y(•)/β2 and then mixed with α2, CDP, and ATP, have been analyzed by stopped-flow absorption spectroscopy, rapid freeze quench EPR spectroscopy, and rapid chemical quench methods. These studies have, for the first time, unmasked the conformational gating. They reveal that the NO(2)Y(•) is reduced to the nitrotyrosinate with biphasic kinetics (283 and 67 s(-1)), that dCDP is produced at 107 s(-1), and that a new Y(•) is produced at 97 s(-1). Studies with pathway mutants suggest that the new Y(•) is predominantly located at 356 in β2. In consideration of these data and the crystal structure of Y(122)NO(2)Y-β2, a mechanism for PCET uncoupling in NO(2)Y(•)-RNR is proposed. PMID:20929229

  10. New insights on pyrimidine signalling within the arterial vasculature - Different roles for P2Y2 and P2Y6 receptors in large and small coronary arteries of the mouse.

    PubMed

    Haanes, Kristian Agmund; Spray, Stine; Syberg, Susanne; Jørgensen, Niklas Rye; Robaye, Bernard; Boeynaems, Jean-Marie; Edvinsson, Lars

    2016-04-01

    Extracellular pyrimidines activate P2Y receptors on both smooth muscle cells and endothelial cells, leading to vasoconstriction and relaxation respectively. The aim of this study was to utilize P2Y knock-out (KO) mice to determine which P2Y receptor subtype are responsible for the contraction and relaxation in the coronary circulation and to establish whether P2Y receptors have different functions along the mouse coronary vascular tree. We tested stable pyrimidine analogues on isolated coronary arteries from P2Y2 and P2Y6 receptor KO mice in a myograph setup. In larger diameter segments of the left descending coronary artery (LAD) (lumen diameter~150μm) P2Y6 is the predominant contractile receptor for both UTP (uridine triphosphate) and UDP (uridine diphosphate) induced contraction. In contrast, P2Y2 receptors mediate endothelial-dependent relaxation. However, in smaller diameter LAD segments (lumen diameter~50μm), the situation is opposite, with P2Y2 being the contractile receptor and P2Y6 functioning as a relaxant receptor along with P2Y2. Immunohistochemistry was used to confirm smooth muscle and endothelial localization of the receptors. In vivo measurements of blood pressure in WT mice revealed a biphasic response to the stable analogue UDPβS. Based on the changes in P2Y receptor functionality along the mouse coronary arterial vasculature, we propose that UTP can act as a vasodilator downstream of its release, after being degraded to UDP, without affecting the contractile pyrimidine receptors. We also propose a model, showing physiological relevance for the changes in purinergic receptor functionality along the mouse coronary vascular tree. PMID:26827897

  11. Gene deletion of P2Y4 receptor lowers exercise capacity and reduces myocardial hypertrophy with swimming exercise.

    PubMed

    Horckmans, Michael; Léon-Gómez, Elvira; Robaye, Bernard; Balligand, Jean-Luc; Boeynaems, Jean-Marie; Dessy, Chantal; Communi, Didier

    2012-10-01

    Nucleotides released within the heart under pathological conditions can be involved in cardioprotection or cardiac fibrosis through the activation purinergic P2Y(2) and P2Y(6) receptors, respectively. We previously demonstrated that adult P2Y(4)-null mice display a microcardia phenotype related to a cardiac angiogenic defect. To evaluate the functional consequences of this defect, we performed here a combination of cardiac monitoring and exercise tests. We investigated the exercise capacity of P2Y(4) wild-type and P2Y(4)-null mice in forced swimming and running tests. Analysis of their stress, locomotion, and resignation was realized in open field, black and white box, and tail suspension experiments. Exercise-induced cardiac hypertrophy was evaluated after repeated and prolonged exercise in P2Y(4) wild-type and P2Y(4)-null hearts. We showed that P2Y(4)-null mice have a lower exercise capacity in both swimming and treadmill tests. This was not related to decreased motivation or increased stress, since open field, white and black box, and mouse tail suspension tests gave comparable results in P2Y(4) wild-type and P2Y(4)-null mice. Heart rate and blood pressure rose normally in P2Y(4)-null swimming mice equipped with a telemetric implant. On the contrary, we observed a delayed recovery of postexercise blood pressure after exercise in P2Y(4)-null mice. The heart rate increment in response to catecholamines was also similar in P2Y(4) wild-type and P2Y(4)-null implanted mice, which is consistent with a similar level of cardiac β-receptor expression. Interestingly, the heart of P2Y(4)-null mice displayed a reduced sympathetic innervation associated with a decreased norepinephrine level. We also demonstrated that exercise-induced cardiac hypertrophy was lower in P2Y(4)-null mice after repeated and prolonged exercise. This was associated with a lower increase in cardiomyocyte size and microvessel density. In conclusion, besides its role in cardiac development, P2Y(4

  12. Synthesis and characterization of nanocrystalline La{sub 2}Mo{sub 2}O{sub 9} fast oxide-ion conductor by an in-situ polymerization method

    SciTech Connect

    Subramania, A. Saradha, T.; Muzhumathi, S.

    2008-05-06

    A nanocrystalline La{sub 2}Mo{sub 2}O{sub 9} powder was synthesized via the pyrolysis of polyacrylate salt precursor prepared by an in situ polymerization of the metal salts and acrylic acid. The pyrolysis behavior of the polymeric precursor was studied by thermal (TG/DTA) analysis. The obtained product was characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM) analysis. The results revealed that the average particle size is {approx}25 nm for La{sub 2}Mo{sub 2}O{sub 9} with good crystallinity. The synthesized nanocrystalline La{sub 2}Mo{sub 2}O{sub 9} powder showed good sinterability and reached {approx}99% of theoretical density when sintered at 800 deg. C for 4 h. The La{sub 2}Mo{sub 2}O{sub 9} sample sintered at 800 deg. C, yield good microstructure with improved conductivity value of about 0.12 S/cm at 800 deg. C.

  13. Effects of a Supported Speed Treadmill Training Exercise Program on Impairment and Function for Children with Cerebral Palsy

    ERIC Educational Resources Information Center

    Johnston, Therese E.; Watson, Kyle E.; Ross, Sandy A.; Gates, Philip E.; Gaughan, John P.; Lauer, Richard T.; Tucker, Carole A.; Engsberg, Jack R.

    2011-01-01

    Aim: To compare the effects of a supported speed treadmill training exercise program (SSTTEP) with exercise on spasticity, strength, motor control, gait spatiotemporal parameters, gross motor skills, and physical function. Method: Twenty-six children (14 males, 12 females; mean age 9y 6mo, SD 2y 2mo) with spastic cerebral palsy (CP; diplegia, n =…

  14. Automated Segmentability Index for Layer Segmentation of Macular SD-OCT Images

    PubMed Central

    Lee, Kyungmoo; Buitendijk, Gabriëlle H.S.; Bogunovic, Hrvoje; Springelkamp, Henriët; Hofman, Albert; Wahle, Andreas; Sonka, Milan; Vingerling, Johannes R.; Klaver, Caroline C.W.; Abràmoff, Michael D.

    2016-01-01

    Purpose To automatically identify which spectral-domain optical coherence tomography (SD-OCT) scans will provide reliable automated layer segmentations for more accurate layer thickness analyses in population studies. Methods Six hundred ninety macular SD-OCT image volumes (6.0 × 6.0 × 2.3 mm3) were obtained from one eyes of 690 subjects (74.6 ± 9.7 [mean ± SD] years, 37.8% of males) randomly selected from the population-based Rotterdam Study. The dataset consisted of 420 OCT volumes with successful automated retinal nerve fiber layer (RNFL) segmentations obtained from our previously reported graph-based segmentation method and 270 volumes with failed segmentations. To evaluate the reliability of the layer segmentations, we have developed a new metric, segmentability index SI, which is obtained from a random forest regressor based on 12 features using OCT voxel intensities, edge-based costs, and on-surface costs. The SI was compared with well-known quality indices, quality index (QI), and maximum tissue contrast index (mTCI), using receiver operating characteristic (ROC) analysis. Results The 95% confidence interval (CI) and the area under the curve (AUC) for the QI are 0.621 to 0.805 with AUC 0.713, for the mTCI 0.673 to 0.838 with AUC 0.756, and for the SI 0.784 to 0.920 with AUC 0.852. The SI AUC is significantly larger than either the QI or mTCI AUC (P < 0.01). Conclusions The segmentability index SI is well suited to identify SD-OCT scans for which successful automated intraretinal layer segmentations can be expected. Translational Relevance Interpreting the quantification of SD-OCT images requires the underlying segmentation to be reliable, but standard SD-OCT quality metrics do not predict which segmentations are reliable and which are not. The segmentability index SI presented in this study does allow reliable segmentations to be identified, which is important for more accurate layer thickness analyses in research and population studies. PMID:27066311

  15. KIC 7668647: a 14 day beaming sdB+WD binary with a pulsating subdwarf

    NASA Astrophysics Data System (ADS)

    Telting, J. H.; Baran, A. S.; Nemeth, P.; Østensen, R. H.; Kupfer, T.; Macfarlane, S.; Heber, U.; Aerts, C.; Geier, S.

    2014-10-01

    The recently discovered subdwarf B (sdB) pulsator KIC 7668647 is one of the 18 pulsating sdB stars detected in the Kepler field. It features a rich g-mode frequency spectrum, with a few low-amplitude p-modes at short periods. This makes it a promising target for a seismic study aiming to constrain the internal structure of this star, and of sdB stars in general. We use new ground-based low-resolution spectroscopy, and the near-continuous 2.88 year Kepler light curve, to reveal that KIC 7668647 consists of a subdwarf B star with an unseen white-dwarf companion with an orbital period of 14.2 d. An orbit with a radial-velocity amplitude of 39 km s-1 is consistently determined from the spectra, from the orbital Doppler beaming seen by Kepler at 163 ppm, and from measuring the orbital light-travel delay of 27 s by timing of the many pulsations seen in the Kepler light curve. The white dwarf has a minimum mass of 0.40 M⊙. We use our high signal-to-noise average spectra to study the atmospheric parameters of the sdB star, and find that nitrogen and iron have abundances close to solar values, while helium, carbon, oxygen and silicon are underabundant relative to the solar mixture. We use the full Kepler Q06-Q17 light curve to extract 132 significant pulsation frequencies. Period-spacing relations and multiplet splittings allow us to identify the modal degree ℓ for the majority of the modes. Using theg-mode multiplet splittings we constrain the internal rotation period at the base of the envelope to 46-48 d as a first seismic result for this star. The few p-mode splittings may point at a slightly longer rotation period further out in the envelope of the star. From mode-visibility considerations we derive that the inclination of the rotation axis of the sdB in KIC 7668647 must be around ~60°. Furthermore, we find strong evidence for a few multiplets indicative of degree 3 ≤ ℓ ≤ 8, which is another novelty in sdB-star observations made possible by Kepler. Based on

  16. The structure, thermal expansion and phase transition properties of Ho{sub 2}Mo{sub 3−x}W{sub x}O{sub 12} (x = 0, 1.0, 2.0) solid solutions

    SciTech Connect

    Liu, X.Z.; Hao, L.J.; Wu, M.M.; Ma, X.B.; Chen, D.F.; Liu, Y.T.

    2015-10-15

    Graphical abstract: A polymorph with Gd{sub 2}Mo{sub 3}O{sub 12}-type structure (space group: Pba2) for negative thermal expansion material Ho{sub 2}Mo{sub 3}O{sub 12} is observed above 700 °C, this polymorphism could be effectively supressed by W-substiution for Mo, the give the temperature dependence of Pba2 phase contents for Ho{sub 2}Mo{sub 3−x}W{sub x}O{sub 12} (x = 0.0, 1.0, 2.0). - Highlights: • The solid solution Ho{sub 2}Mo{sub 3−x}W{sub x}O{sub 12} was investigated by in situ X-ray diffraction. • It is found that the substitution slightly influence thermal expansion property. • A polymorph of Ho{sub 2}Mo{sub 3}O{sub 12} with Pba2 space group was observed above 700 °C. • The W-substitution for Mo effectively suppresses this transformation. - Abstract: Three solid solutions of Ho{sub 2}Mo{sub 3−x}W{sub x}O{sub 12}(x = 0, 1.0, 2.0) were prepared by solid state reaction method, the temperature dependent in-situ X-ray diffraction and thermal analysis were performed to investigate their structure and thermal expansion. All samples have orthorhombic structure(space group Pbcn# 60) with negative thermal expansion at the room temperature. the substitution of W for Mo enlarges the lattice constant and slightly influences the negative thermal expansion. An irreversible phase transformation to the Pba2 phase(Tb{sub 2}Mo{sub 3}O{sub 12} structure) was observed at high temperature for Mo-rich samples. This ploymorphism could be effectively suppressed by the W-substitution for Mo, this phenomenon could be explained by the lower electronegativity of W{sup 6+} than Mo{sup 6+}.

  17. Test characteristics of two rapid antigen detection tests (SD FK50 and SD FK60) for the diagnosis of malaria in returned travellers

    PubMed Central

    Van der Palen, Mirna; Gillet, Philippe; Bottieau, Emmanuel; Cnops, Lieselotte; Van Esbroeck, Marjan; Jacobs, Jan

    2009-01-01

    Background Two malaria rapid diagnostic tests were evaluated in a travel clinic setting: the SD FK50 Malaria Ag Plasmodium falciparum test (a two-band test) and the SD FK60 Malaria Ag P. falciparum/Pan test (a three-band test). Methods A panel of stored whole blood samples (n = 452 and n = 614 for FK50 and FK60, respectively) from returned travellers was used. The reference method was microscopy with PCR in case of discordant results. Results For both tests, overall sensitivity for the detection of P. falciparum was 93.5%, reaching 97.6% and 100% at parasite densities above 100 and 1,000/μl respectively. Overall sensitivities for Plasmodium vivax, Plasmodium ovale and Plasmodium malariae for the FK60 test were 87.5%, 76.3% and 45.2%, but they reached 92.6% and 90.5% for P. vivax and P. ovale at parasite densities above 500/μl. Specificities were above 95% for all species and both tests when corrected by PCR, with visible histidine-rich protein-2 lines for P. malariae (n = 3) and P. vivax and P. ovale (1 sample each). Line intensities were reproducible and correlated to parasite densities. The FK60 tests provided clues to estimate parasite densities for P. falciparum below or above 1,000/μl. Conclusion Both the FK50 and FK60 performed well for the diagnosis of P. falciparum in the present setting, and the FK60 for the diagnosis of P. vivax and P. ovale at parasite densities > 500/μl. The potential use of the FK60 as a semi-quantitative estimation of parasite density needs to be further explored. PMID:19416497

  18. Activation of Distinct P2Y Receptor Subtypes Stimulates Insulin Secretion in MIN6 Mouse Pancreatic β Cells

    PubMed Central

    Balasubramanian, Ramachandran; de Azua, Inigo Ruiz; Wess, Jürgen; Jacobson, Kenneth A.

    2010-01-01

    Extracellular nucleotides and their receptor antagonists have therapeutic potential in disorders such as inflammation, brain disorders, and cardiovascular diseases. Pancreatic β cells express several purinergic receptors, and reported nucleotide effects on insulin secretion are contradictory. We studied the effect of P2Y receptors on insulin secretion and cell death in MIN6, mouse pancreatic β cells. Expression of P2Y1 and P2Y6 receptors was revealed by total mRNA analysis using RT-PCR. MIN6 cells were stimulated in the presence of 16.7 mM glucose with or without P2Y1 and P2Y6 agonists, 2-MeSADP and Up3U, respectively. Both the agonists increased insulin secretion with EC50 values of 44.6±7.0 nM and 30.7±12.7 nM respectively. The insulin secretion by P2Y1 and P2Y6 agonists was blocked by their selective antagonists MRS2179 and MRS2578, respectively. Binding of the selective P2Y1 receptor antagonist radioligand [125I]MRS2500 in MIN6 cell membranes was saturable (KD 4.74±0.47 nM), and known P2Y1 ligands competed with high affinities. Inflammation and glucose toxicity leads to pancreatic β cell death in diabetes. Flow cytometric analysis revealed that Up3U but not 2-MeSADP protected MIN6 cells against TNF-α induced apoptosis. Overall, the results demonstrate that selective stimulation of P2Y1 and P2Y6 receptors increases insulin secretion that accompanies intracellular calcium release, suggesting potential application of P2Y receptor ligands in the treatment of diabetes. PMID:20067775

  19. Reducing the artifacts in the identification of outer retinal boundary in the SD-OCT image with inherit retinal dystrophies.

    PubMed

    Min Zhang; Sekiguchi, Hiroyuki; Uji, Akihito; Yakami, Masahiro; Togashi, Kaori

    2015-08-01

    This paper presents a new SD-OCT outer retinal boundary identification method based on the improved graph-theoretic approach in SD-OCT retinal image, which is robust to the image quality degradation and the pathological morphology variability. The performance of the proposed method was verified using the SD-OCT image database with inherit retinal dystrophies, which suffer from the artifacts most among different macular degeneration diseases. The experimental results of the subjective evaluation indicated that the identification results using the proposed method was substantially improved compared with the current built-in software in the SD-OCT devices. PMID:26737258

  20. Growth and characteristics of self-assembled MoS2/Mo-S-C nanoperiod multilayers for enhanced tribological performance

    PubMed Central

    Xu, Jiao; He, TengFei; Chai, LiQiang; Qiao, Li; Wang, Peng; Liu, WeiMin

    2016-01-01

    Highly ordered MoS2/Mo-S-C nanoperiod multilayers are synthesized by a novel self-assembling mechanism in simultaneous sputtering of MoS2 and graphite targets. The sequential formation of MoS2-riched domain layers and Mo-S-C compositional mixed capping layers reveals no correspondence to the sample stage rotation but is caused by the low energy ion bombardment enhanced interdiffusion. The HRTEM observation shows that the phase segregation normal to the film surface is initiated from substrate-film interlayer with clear contrasts in the first few bi-layers, and then diffuses mutually in a quasiperiodic pattern between two altered sub-layers. Compared with sputtered MoS2 film, the bulk film of multilayers exhibit largely improved toughness under a normal load, and the preferential orientation of sputtered MoS2 in (002) basal planes is significantly enhanced, both of which render the film excellent loads-bearing capacity and lubricant properties. The nano-scratching tests performed on a nanoindentation system suggest that the nano-tribological performance of multilayers is directly determined by the altered structure and properties of neighboring sub-layers until stable tribofilms are formed. Meanwhile, the pin-on-disk tribotests in ambient air, low vacuum and high vacuum provide comparably low friction coefficient yet distinct wear lives in different atmospheres due to the partially restricted humid-sensitivity of sputtered MoS2 phase. PMID:27137707

  1. Growth and characteristics of self-assembled MoS2/Mo-S-C nanoperiod multilayers for enhanced tribological performance.

    PubMed

    Xu, Jiao; He, TengFei; Chai, LiQiang; Qiao, Li; Wang, Peng; Liu, WeiMin

    2016-01-01

    Highly ordered MoS2/Mo-S-C nanoperiod multilayers are synthesized by a novel self-assembling mechanism in simultaneous sputtering of MoS2 and graphite targets. The sequential formation of MoS2-riched domain layers and Mo-S-C compositional mixed capping layers reveals no correspondence to the sample stage rotation but is caused by the low energy ion bombardment enhanced interdiffusion. The HRTEM observation shows that the phase segregation normal to the film surface is initiated from substrate-film interlayer with clear contrasts in the first few bi-layers, and then diffuses mutually in a quasiperiodic pattern between two altered sub-layers. Compared with sputtered MoS2 film, the bulk film of multilayers exhibit largely improved toughness under a normal load, and the preferential orientation of sputtered MoS2 in (002) basal planes is significantly enhanced, both of which render the film excellent loads-bearing capacity and lubricant properties. The nano-scratching tests performed on a nanoindentation system suggest that the nano-tribological performance of multilayers is directly determined by the altered structure and properties of neighboring sub-layers until stable tribofilms are formed. Meanwhile, the pin-on-disk tribotests in ambient air, low vacuum and high vacuum provide comparably low friction coefficient yet distinct wear lives in different atmospheres due to the partially restricted humid-sensitivity of sputtered MoS2 phase. PMID:27137707

  2. In Situ Thermo-magnetic Investigation of the Austenitic Phase During Tempering of a 13Cr6Ni2Mo Supermartensitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Bojack, A.; Zhao, L.; Morris, P. F.; Sietsma, J.

    2014-09-01

    The formation of austenite during tempering of a 13Cr6Ni2Mo supermartensitic stainless steel (X2CrNiMoV13-5-2) was investigated using an in situ thermo-magnetic technique to establish the kinetics of the martensite to austenite transformation and the stability of austenite. The austenite fraction was obtained from in situ magnetization measurements. It was found that during heating to the tempering temperature 1 to 2 vol pct of austenite, retained during quenching after the austenitization treatment, decomposed between 623 K and 753 K (350 °C and 480 °C). The activation energy for martensite to austenite transformation was found by JMAK-fitting to be 233 kJ/mol. This value is similar to the activation energy for Ni and Mn diffusion in iron and supports the assumption that partitioning of Ni and Mn to austenite are mainly rate determining for the austenite formation during tempering. This also indicates that the stability of austenite during cooling after tempering depends on these elements. With increasing tempering temperature the thermal stability of austenite is decreasing due to the lower concentrations of austenite-stabilizing elements in the increased fraction of austenite. After cooling from the tempering temperature the retained austenite was further partially decomposed during holding at room temperature. This appears to be related to previous martensite formation during cooling.

  3. In Situ Thermo-magnetic Investigation of the Austenitic Phase During Tempering of a 13Cr6Ni2Mo Supermartensitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Bojack, A.; Zhao, L.; Morris, P. F.; Sietsma, J.

    2014-12-01

    The formation of austenite during tempering of a 13Cr6Ni2Mo supermartensitic stainless steel (X2CrNiMoV13-5-2) was investigated using an in situ thermo-magnetic technique to establish the kinetics of the martensite to austenite transformation and the stability of austenite. The austenite fraction was obtained from in situ magnetization measurements. It was found that during heating to the tempering temperature 1 to 2 vol pct of austenite, retained during quenching after the austenitization treatment, decomposed between 623 K and 753 K (350 °C and 480 °C). The activation energy for martensite to austenite transformation was found by JMAK-fitting to be 233 kJ/mol. This value is similar to the activation energy for Ni and Mn diffusion in iron and supports the assumption that partitioning of Ni and Mn to austenite are mainly rate determining for the austenite formation during tempering. This also indicates that the stability of austenite during cooling after tempering depends on these elements. With increasing tempering temperature the thermal stability of austenite is decreasing due to the lower concentrations of austenite-stabilizing elements in the increased fraction of austenite. After cooling from the tempering temperature the retained austenite was further partially decomposed during holding at room temperature. This appears to be related to previous martensite formation during cooling.

  4. Self-powdering and nonlinear optical domain structures in ferroelastic β‧-Gd2(MoO4)3 crystals formed in glass

    NASA Astrophysics Data System (ADS)

    Tsukada, Y.; Honma, T.; Komatsu, T.

    2009-08-01

    Ferroelastic β'-Gd 2(MoO 4) 3, (GMO), crystals are formed through the crystallization of 21.25Gd 2O 3-63.75MoO 3-15B 2O 3 glass (mol%), and two scientific curious phenomena are observed. (1) GMO crystals formed in the crystallization break into small pieces with a triangular prism or pyramid shape having a length of 50-500 μm spontaneously during the crystallizations in the inside of an electric furnace, not during the cooling in air after the crystallization. This phenomenon is called "self-powdering phenomenon during crystallization" in this paper. (2) Each self-powdered GMO crystal grain shows a periodic domain structure with different refractive indices, and a spatially periodic second harmonic generation (SHG) depending on the domain structure is observed. It is proposed from polarized micro-Raman scattering spectra and the azimuthal dependence of second harmonic intensities that GMO crystals are oriented in each crystal grain and the orientation of (MoO 4) 2- tetrahedra in GMO crystals changes periodically due to spontaneous strains in ferroelastic GMO crystals.

  5. Pressure evolution of the potential barriers of phase transition of MoS2, MoSe2 and MoTe2.

    PubMed

    Fan, Xaiofeng; Singh, David J; Jiang, Q; Zheng, W T

    2016-04-28

    Two-dimensional crystals with weak layer interactions, such as twisted graphene, have been a focus of research recently. As a representative example, transitional metal dichalcogenides show a lot of fascinating properties due to stacking orders and spin-orbit coupling. We analyzed the dynamic energy barrier of possible phase transitions in MoX2 (X = S, Se and Te) with first-principles methods. In the structural transition from 2Hc to 2Ha, the energy barrier is found to be increased following an increase of pressure which is different from the phase transition in usual semiconductors. Among MoS2, MoSe2 and MoTe2, the energy barrier of MoS2 is the lowest and the stability of both 2Hc and 2Ha is reversed under pressure for MoS2. It is found that the absence of a phase transition in MoSe2 and MoTe2 is due to the competition between van der Waals interaction of layers and the coulomb interaction of Mo and X in nearest-neighbor layer of Mo in both phases. PMID:27074155

  6. High-pressure x-ray diffraction, absorption, luminescence, and Raman-scattering study of Cs{sub 2}MoS{sub 4}

    SciTech Connect

    Lorenz, B.; Orgzall, I.; Dorhout, P.K.; Raymond, C.C.; Brister, K.; Weishaupt, K.; DAdamo, R.; Hochheimer, H.D.

    1997-02-01

    Cesium thiomolybdate, Cs{sub 2}MoS{sub 4}, has been investigated at pressures up to 12 GPa. Two phase transitions have been detected by absorption measurements, Raman spectroscopy, and energy dispersive x-ray diffraction. The first phase transition to a monoclinic phase II [a=14.061(9) {Angstrom}, b=11.552(7) {Angstrom}, c=9.852(6) {Angstrom}, {beta}=97.14(6){degree}] has been observed at 8.0 GPa. The second transition at 9.7 GPa has been observed from the monoclinic phase II to an orthorhombic phase III [a=12.085(4) {Angstrom}, b=15.707(6) {Angstrom}, c=11.828(5) {Angstrom}]. Absorption and luminescence measurements have indicated an increase in the absorption edge energy with pressure up to {approximately}3 GPa. At pressures greater than 3.5 GPa, the absorption energy decreases. Raman spectroscopy has revealed a low-frequency phonon mode with a negative pressure shift in the low-pressure phase I. The pressure-temperature phase diagram has been determined up to 250{degree}C. The transition pressures decrease linearly with slopes of {approximately}{minus}0.013 GPa/{degree}C. Models for the pressure-induced structural and electronic transitions are proposed. {copyright} {ital 1997} {ital The American Physical Society}

  7. Growth and characteristics of self-assembled MoS2/Mo-S-C nanoperiod multilayers for enhanced tribological performance

    NASA Astrophysics Data System (ADS)

    Xu, Jiao; He, Tengfei; Chai, Liqiang; Qiao, Li; Wang, Peng; Liu, Weimin

    2016-05-01

    Highly ordered MoS2/Mo-S-C nanoperiod multilayers are synthesized by a novel self-assembling mechanism in simultaneous sputtering of MoS2 and graphite targets. The sequential formation of MoS2-riched domain layers and Mo-S-C compositional mixed capping layers reveals no correspondence to the sample stage rotation but is caused by the low energy ion bombardment enhanced interdiffusion. The HRTEM observation shows that the phase segregation normal to the film surface is initiated from substrate-film interlayer with clear contrasts in the first few bi-layers, and then diffuses mutually in a quasiperiodic pattern between two altered sub-layers. Compared with sputtered MoS2 film, the bulk film of multilayers exhibit largely improved toughness under a normal load, and the preferential orientation of sputtered MoS2 in (002) basal planes is significantly enhanced, both of which render the film excellent loads-bearing capacity and lubricant properties. The nano-scratching tests performed on a nanoindentation system suggest that the nano-tribological performance of multilayers is directly determined by the altered structure and properties of neighboring sub-layers until stable tribofilms are formed. Meanwhile, the pin-on-disk tribotests in ambient air, low vacuum and high vacuum provide comparably low friction coefficient yet distinct wear lives in different atmospheres due to the partially restricted humid-sensitivity of sputtered MoS2 phase.

  8. Oxygen Point Defect Chemistry in Ruddlesden-Popper Oxides (La1-xSrx)2MO4±δ (M = Co, Ni, Cu).

    PubMed

    Xie, Wei; Lee, Yueh-Lin; Shao-Horn, Yang; Morgan, Dane

    2016-05-19

    Stability of oxygen point defects in Ruddlesden-Popper oxides (La1-xSrx)2MO4±δ (M = Co, Ni, Cu) is studied with density functional theory calculations to determine their stable sites, charge states, and energetics as functions of Sr content (x), transition metal (M), and defect concentration (δ). We demonstrate that the dominant O point defects can change between oxide interstitials, peroxide interstitials, and vacancies. In general, increasing x and atomic number of M stabilizes peroxide over oxide interstitials as well as vacancies over both peroxide and oxide interstitials; increasing δ destabilizes both oxide interstitials and vacancies but barely affects peroxide interstitials. We also demonstrate that the O 2p-band center is a powerful descriptor for these materials and correlates linearly with the formation energy of all defects. The trends of formation energy versus x, M, and δ and the correlation with O 2p-band center are explained in terms of oxidation chemistry and electronic structure. PMID:27157124

  9. Facile synthesis of a MoO2-Mo2C-C composite and its application as favorable anode material for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Zhu, Yanping; Wang, Shaofeng; Zhong, Yijun; Cai, Rui; Li, Li; Shao, Zongping

    2016-03-01

    A composite of MoO2-Mo2C-C is fabricated through a facile ion-exchange route for the first time as an alternative anode material for lithium-ion batteries (LIBs). A macroporous cinnamic anion-exchange resin interacts with ammonium molybdate tetrahydrate in aqueous solution, and the product is then calcined under an inert gas atmosphere. The interaction between the resin and ammonium molybdate tetrahydrate results in an atomic level dispersion of the molybdenum over the organic carbon precursor (resin), while the calcination process allows the formation of MoO2 and Mo2C as well as the pyrolysis of resin to solid carbon. According to field-emission scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements, ultrafine MoO2 and Mo2C nanoparticles are uniformly dispersed but firmly attached within an amorphous carbon framework. When evaluated as an anode material, the as-synthesized sample exhibits superior electrochemical performance. The specific discharge capacity is as high as 1491 mA h g-1 in the first cycle and 724 mA h g-1 over 50 cycles at a current density of 0.2 A g-1. This simple, environmentally friendly, low-cost and easily scaled up method, has significant potential for mass industrial production of MoO2-based material as next-generation anode material of LIBs with wide application capability.

  10. High-Performance WSe2, MoS2, and MoSe2 Transistors Enabled by a New Contact Strategy

    NASA Astrophysics Data System (ADS)

    Chuang, Hsun Jen; Chamlagain, Bhim; Koehler, Michael; Perera1, Meeghage Madusanka; Yan, Jiaqiang; Mandrus, David; Tománek, David; Zhou, Zhixian

    Fabrication of high-performance transistors of transition metal dichalcogenides (TMDs) including WSe2, MoS2, and MoSe2 has been a major challenge in 2D electronics. The performance of current metal-contacted TMDs is limited by the presence of a significant Schottky barrier in most cases. Here we introduce a new strategy for fabricating low-resistance ohmic contacts to a variety of TMDs. We demonstrate low contact resistance ~ 0.3 k Ωμ m, high on/off ratios up to >109, and high drive currents exceeding 320 μA μm- 1 in few-layer WSe2 field-effect transistors (FETs). These favorable characteristics are combined with a two-terminal field-effect hole mobility μFE ~ 2x102 cm2 V-1s-1 at room temperature, which increases to >2x 103 cm2 V- 1 s-1 at cryogenic temperatures. We observe a similar performance also in MoS2 and MoSe2 FETs. We acknowledge the partial support by NSF Grant Number DMR-1308436 and the WSU Presidential Research Enhancement Award.

  11. Benzofuran-substituted urea derivatives as novel P2Y(1) receptor antagonists.

    PubMed

    Thalji, Reema K; Aiyar, Nambi; Davenport, Elizabeth A; Erhardt, Joseph A; Kallal, Lorena A; Morrow, Dwight M; Senadhi, Shobha; Burns-Kurtis, Cynthia L; Marino, Joseph P

    2010-07-15

    Benzofuran-substituted urea analogs have been identified as novel P2Y(1) receptor antagonists. Structure-activity relationship studies around the urea and the benzofuran moieties resulted in compounds having improved potency. Several analogs were shown to inhibit ADP-mediated platelet activation. PMID:20542694

  12. P2Y6 Receptor-Mediated Microglial Phagocytosis in Radiation-Induced Brain Injury.

    PubMed

    Xu, Yongteng; Hu, Weihan; Liu, Yimin; Xu, Pengfei; Li, Zichen; Wu, Rong; Shi, Xiaolei; Tang, Yamei

    2016-08-01

    Microglia are the resident immune cells and the professional phagocytic cells of the CNS, showing a multitude of cellular responses after activation. However, how microglial phagocytosis changes and whether it is involved in radiation-induced brain injury remain unknown. In the current study, we found that microglia were activated and microglial phagocytosis was increased by radiation exposure both in cultured microglia in vitro and in mice in vivo. Radiation increased the protein expression of the purinergic receptor P2Y6 receptor (P2Y6R) located on microglia. The selective P2Y6 receptor antagonist MRS2578 suppressed microglial phagocytosis after radiation exposure. Inhibition of microglial phagocytosis increased inhibitory factor Nogo-A and exacerbated radiation-induced neuronal apoptosis and demyelination. We also found that the levels of protein expression for phosphorylated Ras-related C3 botulinum toxin substrate 1 (Rac1) and myosin light chain kinase (MLCK) were elevated, indicating that radiation exposure activated Rac1 and MLCK. The Rac1 inhibitor NSC23766 suppressed expression of MLCK, indicating that the Rac1-MLCK pathway was involved in microglial phagocytosis. Taken together, these findings suggest that the P2Y6 receptor plays a critical role in mediating microglial phagocytosis in radiation-induced brain injury, which might be a potential strategy for therapeutic intervention to alleviate radiation-induced brain injury. PMID:26099306

  13. Personalized antiplatelet therapy with P2Y12 receptor inhibitors: benefits and pitfalls

    PubMed Central

    Winter, Max-Paul; Koziński, Marek; Kubica, Jacek; Aradi, Daniel

    2015-01-01

    Antiplatelet therapy with P2Y12 receptor inhibitors has become the cornerstone of medical treatment in patients with acute coronary syndrome, after percutaneous coronary intervention and in secondary prevention of atherothrombotic events. Clopidogrel used to be the most broadly prescribed P2Y12 receptor inhibitor with undisputable benefits especially in combination with aspirin, but a considerable number of clopidogrel-treated patients experience adverse thrombotic events in whom insufficient P2Y12-inhibition and a consequential high on-treatment platelet reactivity is a common finding. This clinically relevant limitation of clopidogrel has driven the increased use of new antiplatelet agents. Prasugrel (a third generation thienopyridine) and ticagrelor (a cyclopentyl-triazolo-pyrimidine) feature more potent and predictable P2Y12-inhibition compared to clopidogrel, which translates into improved ischemic outcomes. However, excessive platelet inhibition and consequential low on-treatment platelet reactivity comes at the price of increased risk of major bleeding. The majority of randomized clinical trials failed to demonstrate improved clinical outcomes with platelet function testing and tailored antiplatelet therapy, but results of all recent trials of potent antiplatelets and prolonged antiplatelet durations point towards a need for individualized antiplatelet approach in order to decrease thrombotic events without increasing bleeding. This review focuses on potential strategies for personalizing antiplatelet treatment. PMID:26677375

  14. From {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}O(MoO{sub 4}){sub 4}]{sup 6-} to {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})]{sup 6-} infinite chains in A{sub 6}U{sub 2}Mo{sub 4}O{sub 21} (A=Na, K, Rb, Cs) compounds: Synthesis and crystal structure of Cs{sub 6}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})

    SciTech Connect

    Yagoubi, S.; Obbade, S.; Saad, S.; Abraham, F.

    2011-05-15

    A new caesium uranyl molybdate belonging to the M{sub 6}U{sub 2}Mo{sub 4}O{sub 21} family has been synthesized by solid-state reaction and its structure determined from single-crystal X-ray diffraction data. Contrary to the other alkali uranyl molybdates of this family (A=Na, K, Rb) where molybdenum atoms adopt only tetrahedral coordination and which can be formulated A{sub 6}[(UO{sub 2}){sub 2}O(MoO{sub 4}){sub 4}], the caesium compound Cs{sub 6}U{sub 2}Mo{sub 4}O{sub 21} should be written Cs{sub 6}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})] with molybdenum atoms in tetrahedral and square pyramidal environments. Cs{sub 6}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})] crystallizes in the triclinic symmetry with space group P1-bar and a=10.4275(14) A, b=15.075(2) A, c=17.806(2) A, {alpha}=70.72(1){sup o}, {beta}=80.38(1){sup o} and {gamma}=86.39(1){sup o}, V=2604.7(6) A{sup 3}, Z=4, {rho}{sub mes}=5.02(2) g/cm{sup 3} and {rho}{sub cal}=5.08(3) g/cm{sup 3}. A full-matrix least-squares refinement on the basis of F{sup 2} yielded R{sub 1}=0.0464 and wR{sub 2}=0.0950 for 596 parameters with 6964 independent reflections with I{>=}2{sigma}(I) collected on a BRUKER AXS diffractometer with Mo(K{alpha}) radiation and a CCD detector. The crystal structure of Cs compound is characterized by {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})]{sup 6-} parallels chains built from U{sub 2}O{sub 13} dimeric units, MoO{sub 4} tetrahedra and MoO{sub 5} square pyramids, whereas, Na, K and Rb compounds are characterized by {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}O(MoO{sub 4}){sub 4}]{sup 6-} parallel chains formulated simply of U{sub 2}O{sub 13} units and MoO{sub 4} tetrahedra. Infrared spectroscopy measurements using powdered samples synthesized by solid-state reaction, confirm the structural results. The thermal stability and the electrical conductivity are also studied. The four compounds decompose at low temperature (between 540 and 610 {sup o

  15. Adenine Nucleotide Analogues Locked in a Northern Methanocarba Conformation: Enhanced Stability and Potency as P2Y1 Receptor Agonists

    PubMed Central

    Ravi, R. Gnana; Kim, Hak Sung; Servos, Jörg; Zimmermann, Herbert; Lee, Kyeong; Maddileti, Savitri; Boyer, José L.; Harden, T. Kendall; Jacobson, Kenneth A.

    2016-01-01

    Preference for the Northern (N) ring conformation of the ribose moiety of nucleotide 5′-triphosphate agonists at P2Y1, P2Y2, P2Y4, and P2Y11 receptors, but not P2Y6 receptors, was established using a ring-constrained methanocarba (a 3.1.0-bicyclohexane) ring as a ribose substitute (Kim et al. J. Med. Chem. 2002, 45, 208–218.). We have now combined the ring-constrained (N)-methanocarba modification of adenine nucleotides with other functionalities known to enhance potency at P2 receptors. The potency of the newly synthesized analogues was determined in the stimulation of phospholipase C through activation of turkey erythrocyte P2Y1 or human P2Y1 and P2Y2 receptors stably expressed in astrocytoma cells. An (N)-methanocarba-2-methylthio-ADP analogue displayed an EC50 at the hP2Y1 receptor of 0.40 nM and was 55-fold more potent than the corresponding triphosphate and 16-fold more potent than the riboside 5′-diphosphate. 2-Cl–(N)-methanocarba-ATP and its N6-Me analogue were also highly selective, full agonists at P2Y1 receptors. The (N)-methanocarba-2-methylthio and 2-chloromonophosphate analogues were full agonists exhibiting micromolar potency at P2Y1 receptors, while the corresponding ribosides were inactive. Although β,γ-methylene-ATP was inactive at P2Y receptors, β,γ-methylene-(N)-methanocarba-ATP was a potent hP2Y1 receptor agonist with an EC50 of 160 nM and was selective versus hP2Y2 and hP2Y4 receptors. The rates of hydrolysis of Northern (N) and Southern (S) methanocarba analogues of AMP by rat 5′-ectonucleotidase were negligible. The rates of hydrolysis of the corresponding triphosphates by recombinant rat NTPDase1 and 2 were studied. Both isomers were hydrolyzed by NTPDase 1 at about half the rate of ATP hydrolysis. The (N) isomer was hardly hydrolyzed by NTPDase 2, while the (S) isomer was hydrolyzed at one-third of the rate of ATP hydrolysis. This suggests that new, more stable and selective nucleotide agonists may be designed on the basis of

  16. Chiral magnetic effect and SdH oscillations in Dirac and Weyl metals

    NASA Astrophysics Data System (ADS)

    Kharzeev, Dmitri; Monteiro, Gustavo; Abanov, Alexander

    2015-03-01

    In the present work, we consider the interplay of chiral anomaly and Shubnikov-de Haas (SdH) oscillations in recently discovered Dirac metals. The kinetic theory describing the transport in these new materials should account for the chiral anomaly. The unbalanced number of chiral zero-modes in the presence of magnetic field due to the chiral anomaly gives rise to an additional contribution to the electric current - the chiral magnetic effect. The zero-modes are topologically protected from scattering and their contribution to the current leads to a negative magnetoresistance. This effect was recently observed in measurements on the Dirac semimetal Cd3 As2, where the longitudinal (with respect to magnetic field) component of the resistivity tensor shows a negative slope, along with pronounced Shubnikov-de Haas (SdH) oscillations. We develop a combined description of both these phenomena within a chiral kinetic theory.

  17. HS 2333 + 3927: a new sdB binary with a large reflection effect

    NASA Astrophysics Data System (ADS)

    Karl, C. A.; Heber, U.; Drechsel, H.; Napiwotzki, R.; Altmann, M.; Østensen, R.; Folkes, S.; Solheim, J. E.; Cordes, O.; Voss, B.; Koester, D.

    2004-06-01

    We report the discovery of a binary, HS 2233 + 3927, consisting of an sdB star with a faint companion. From its lightcurve the orbital period of 14,844 s, the mass ratio, the inclination, and other system parameters are derived. The companion does not contribute to the optical light of the system except through a strong reflection effect. The semi-amplitude of the radial velocity curve K 1= 89.6 km/s-1 and a mass function of f(m) = 0.013 M ⊙ are determined. A preliminary spectroscopic analysis of the blue spectra using NLTE model atmospheres results in Teff= 36 500 K, log g= 5.70, and log(n He/n H) =-2.15. These parameters are typical for sdB stars, the companion is probably an M dwarf.

  18. Fragmentation-aware service provisioning for advance reservation multicast in SD-EONs.

    PubMed

    Li, Shengru; Lu, Wei; Liu, Xiahe; Zhu, Zuqing

    2015-10-01

    In this paper, we study the service provisioning schemes for dynamic advance reservation (AR) multicast requests in elastic optical networks (EONs). We first propose several algorithms that can handle the service scheduling and routing and spectrum assignment (RSA) of AR multicast requests jointly, including an integrated two-dimensional fragmentation-aware RSA (2D-FMA) that can alleviate the 2D fragmentation caused by light-tree provisioning. Then, we leverage the idea of software-defined EONs (SD-EONs) that utilizes OpenFlow (OF) in the control plane to demonstrate and evaluate the proposed algorithms. Specifically, we build an SD-EON control plane testbed, implement the algorithms in it, and perform control plane experiments on dynamic AR multicast provisioning. The results indicate that 2D-FMA achieves the best blocking performance and provides the shortest average setup delay. PMID:26480094

  19. Correlations of excited states for sd bosons in the presence of random interactions

    SciTech Connect

    Lei, Y.; Zhao, Y. M.; Yoshida, N.; Arima, A.

    2011-04-15

    In this work we study the yrast states of sd-boson systems in the presence of random interactions. It is found that the yrast states with spin-zero ground states among the random ensemble exhibit strong correlations, characterized by anharmonic vibration, s-boson or d-boson condensation, as well as vibrational and rotational motions. We study these correlations explicitly based on their wave functions and the features of two-body interactions in the random ensemble.

  20. Inversion for Eigenvalues and Modes Using Sierra-SD and ROL.

    SciTech Connect

    Walsh, Timothy; Aquino, Wilkins; Ridzal, Denis; Kouri, Drew Philip

    2015-12-01

    In this report we formulate eigenvalue-based methods for model calibration using a PDE-constrained optimization framework. We derive the abstract optimization operators from first principles and implement these methods using Sierra-SD and the Rapid Optimization Library (ROL). To demon- strate this approach, we use experimental measurements and an inverse solution to compute the joint and elastic foam properties of a low-fidelity unit (LFU) model.

  1. Metabolomics approach to serum biomarker for loperamide-induced constipation in SD rats.

    PubMed

    Kim, Ji-Eun; Lee, Young-Ju; Kwak, Moon-Hwa; Jun, Go; Koh, Eun-Kyoung; Song, Sung-Hwa; Seong, Ji-Eun; Kim, Ji Won; Kim, Kyu-Bong; Kim, Suhkmann; Hwang, Dae-Youn

    2014-03-01

    Loperamide has long been known as an opioid-receptor agonist useful as a drug for treatment of diarrhea resulting from gastroenteritis or inflammatory bowel disease as well as to induce constipation. To determine and characterize putative biomarkers that can predict constipation induced by loperamide treatment, alteration of endogenous metabolites was measured in the serum of Sprague Dawley (SD) rats treated with loperamide for 3 days using (1)H nuclear magnetic resonance ((1)H NMR) spectral data. The amounts and weights of stool and urine excretion were significantly lower in the loperamide-treated group than the No-treated group, while the thickness of the villus, crypt layer, and muscle layer was decreased in the transverse colon of the same group. The concentrations of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatinine (Cr) were also slightly changed in the loperamide-treated group, although most of the serum components were maintained at a constant level. Furthermore, pattern recognition of endogenous metabolites showed completely separate clustering of the serum analysis parameters between the No-treated group and loperamide-treated group. Among 35 endogenous metabolites, four amino acids (alanine, glutamate, glutamine and glycine) and six endogenous metabolites (acetate, glucose, glycerol, lactate, succinate and taurine) were dramatically decreased in loperamide-treated SD rats. These results provide the first data pertaining to metabolic changes in SD rats with loperamide-induced constipation. Additionally, these findings correlate the changes in 10 metabolites with constipation. PMID:24707303

  2. Symmetry of Isoscalar Matrix Elements and Systematics in the sd and beginning of fp shells

    NASA Astrophysics Data System (ADS)

    Orce, J. N.; Petkov, P.; Velázquez, V.; McKay, C. J.; Lesher, S. R.; Choudry, S.; Mynk, M.; Linnemann, A.; Jolie, J.; von Brentano, P.; Werner, V.; Yates, S. W.; McEllistrem, M. T.

    2006-03-01

    A careful determination of the lifetime and measurement of the branching ratio for decay of the first 2T=1+ state in 42Sc has allowed an accurate experimental test of charge independence in the A = 42 isobaric triplet. A lifetime of 69(17) fs was measured at the University of Kentucky, while relative intensities for the 975 keV and 1586 keV transitions depopulating the first 2T=1+ state have been determined at the University of Cologne as 100(1) and 8(1), respectively. Both measurements give an isoscalar matrix element, M0, of 6.4(9) (W.u.)1/2. This result confirms charge independence for the A=42 isobaric triplet. Shell model calculations have been carried out for understanding the global trend of M0 values for A = 4n + 2 isobaric triplets ranging from A = 18 to A = 42. The 21 (T=1)+ → 01 (T=1)+ transition energies, reduced transition probabilities and M0 values are reproduced to a high degree of accuracy. The trend of M0 strength along the sd shell is interpreted in terms of the shell structure. Certain discrepancies arise at the extremes of the sd shell, for the A = 18 and A = 38 isobaric triplets, which might be explained in terms of the low valence space at the extremes of the sd shell.

  3. Geology of the USW SD-12 drill hole Yucca Mountain, Nevada

    SciTech Connect

    Rautman, C.A.; Engstrom, D.A.

    1996-11-01

    Drill hole USW SD-12 is one of several holes drilled under Site Characterization Plan Study 8.3.1.4.3.1, also known as the {open_quotes}Systematic Drilling Program,{close_quotes} as part of the U.S. Department of Energy characterization program at Yucca Mountain, Nevada, which has been proposed as the potential location of a repository for high-level nuclear waste. The SD-12 drill hole is located in the central part of the potential repository area, immediately to the west of the Main Test Level drift of the Exploratory Studies Facility and slightly south of midway between the North Ramp and planned South Ramp declines. Drill hole USW SD-12 is 2166.3 ft (660.26 m) deep, and the core recovered essentially complete sections of ash-flow tuffs belonging to the lower half of the Tiva Canyon Tuff, the Pah Canyon Tuff, and the Topopah Spring Tuff, all of which are part of the Miocene Paintbrush Group. A virtually complete section of the Calico Hills Formation was also recovered, as was core from the entire Prow Pass Tuff formation of the Crater Flat Group.

  4. Metabolomics approach to serum biomarker for loperamide-induced constipation in SD rats

    PubMed Central

    Kim, Ji-Eun; Lee, Young-Ju; Kwak, Moon-Hwa; Jun, Go; Koh, Eun-Kyoung; Song, Sung-Hwa; Seong, Ji-Eun; Kim, Ji Won; Kim, Kyu-Bong; Kim, Suhkmann

    2014-01-01

    Loperamide has long been known as an opioid-receptor agonist useful as a drug for treatment of diarrhea resulting from gastroenteritis or inflammatory bowel disease as well as to induce constipation. To determine and characterize putative biomarkers that can predict constipation induced by loperamide treatment, alteration of endogenous metabolites was measured in the serum of Sprague Dawley (SD) rats treated with loperamide for 3 days using 1H nuclear magnetic resonance (1H NMR) spectral data. The amounts and weights of stool and urine excretion were significantly lower in the loperamide-treated group than the No-treated group, while the thickness of the villus, crypt layer, and muscle layer was decreased in the transverse colon of the same group. The concentrations of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatinine (Cr) were also slightly changed in the loperamide-treated group, although most of the serum components were maintained at a constant level. Furthermore, pattern recognition of endogenous metabolites showed completely separate clustering of the serum analysis parameters between the No-treated group and loperamide-treated group. Among 35 endogenous metabolites, four amino acids (alanine, glutamate, glutamine and glycine) and six endogenous metabolites (acetate, glucose, glycerol, lactate, succinate and taurine) were dramatically decreased in loperamide-treated SD rats. These results provide the first data pertaining to metabolic changes in SD rats with loperamide-induced constipation. Additionally, these findings correlate the changes in 10 metabolites with constipation. PMID:24707303

  5. SD-MSAEs: Promoter recognition in human genome based on deep feature extraction.

    PubMed

    Xu, Wenxuan; Zhang, Li; Lu, Yaping

    2016-06-01

    The prediction and recognition of promoter in human genome play an important role in DNA sequence analysis. Entropy, in Shannon sense, of information theory is a multiple utility in bioinformatic details analysis. The relative entropy estimator methods based on statistical divergence (SD) are used to extract meaningful features to distinguish different regions of DNA sequences. In this paper, we choose context feature and use a set of methods of SD to select the most effective n-mers distinguishing promoter regions from other DNA regions in human genome. Extracted from the total possible combinations of n-mers, we can get four sparse distributions based on promoter and non-promoters training samples. The informative n-mers are selected by optimizing the differentiating extents of these distributions. Specially, we combine the advantage of statistical divergence and multiple sparse auto-encoders (MSAEs) in deep learning to extract deep feature for promoter recognition. And then we apply multiple SVMs and a decision model to construct a human promoter recognition method called SD-MSAEs. Framework is flexible that it can integrate new feature extraction or new classification models freely. Experimental results show that our method has high sensitivity and specificity. PMID:27018214

  6. Symmetry of Isoscalar Matrix Elements and Systematics in the sd and beginning of fp shells

    SciTech Connect

    Orce, J. N.; McKay, C. J.; Lesher, S. R.; Choudry, S.; Mynk, M.; McEllistrem, M. T.; Petkov, P.; Velazquez, V.; Linnemann, A.; Jolie, J.; Brentano, P. von; Werner, V.; Yates, S. W.

    2006-03-13

    A careful determination of the lifetime and measurement of the branching ratio for decay of the first 2{sub T=1}{sup +} state in 42Sc has allowed an accurate experimental test of charge independence in the A = 42 isobaric triplet. A lifetime of 69(17) fs was measured at the University of Kentucky, while relative intensities for the 975 keV and 1586 keV transitions depopulating the first 2{sub T=1}{sup +} state have been determined at the University of Cologne as 100(1) and 8(1), respectively. Both measurements give an isoscalar matrix element, M0, of 6.4(9) (W.u.)1/2. This result confirms charge independence for the A=42 isobaric triplet. Shell model calculations have been carried out for understanding the global trend of M0 values for A = 4n + 2 isobaric triplets ranging from A = 18 to A = 42. The 2{sub 1(T=1)}{sup +} {yields} 0{sub 1(T=1)}{sup +} transition energies, reduced transition probabilities and M0 values are reproduced to a high degree of accuracy. The trend of M0 strength along the sd shell is interpreted in terms of the shell structure. Certain discrepancies arise at the extremes of the sd shell, for the A = 18 and A 38 isobaric triplets, which might be explained in terms of the low valence space at the extremes of the sd shell.

  7. Scientific Use of the Sampler, Drill and Distribution Subsystem (SD2)

    NASA Astrophysics Data System (ADS)

    Armellin, R.; Di Lizia, P.; Crepaldi, M.; Bernelli-Zazzera, F.; Ercoli Finzi, A.

    Rosetta is the third cornerstone mission of the European Space Agency scientific program "Horizon 2000". Rosetta will be the first spacecraft to orbit around a comet nucleus. It was launched in March 2004 and will reach the comet 67P/ChurymovGerasimenko in 2014. A lander (Philae) will be released and land on the comet surface for in-situ investigation. One of the key subsystems of the lander Philae is the Sampler, Drill and Distribution (SD2) subsystem. SD2 provides in-situ operations devoted to soil drilling, samples collection, and their distribution to two evolved gas analyzers (COSAC and PTOLEMY) and one imaging instrument (ÇIVA). Recent studies have proven the existence of a correlation between the drill behavior during perforation and the mechanical characteristics of the cometary soil. This outlines the possibility of using SD2 not only as a tool to support other instruments, but also as a scientific instrument itself. In this paper the possibility of using the drill as a quasi-static penetrator is presented. Within this approach, laboratory tests on glass-foam specimens of different porosity show that the drill behaviour during penetration can be exploited for cometary soil characterization.

  8. Multimodal segmentation of optic disc and cup from stereo fundus and SD-OCT images

    NASA Astrophysics Data System (ADS)

    Miri, Mohammad Saleh; Lee, Kyungmoo; Niemeijer, Meindert; Abràmoff, Michael D.; Kwon, Young H.; Garvin, Mona K.

    2013-03-01

    Glaucoma is one of the major causes of blindness worldwide. One important structural parameter for the diagnosis and management of glaucoma is the cup-to-disc ratio (CDR), which tends to become larger as glaucoma progresses. While approaches exist for segmenting the optic disc and cup within fundus photographs, and more recently, within spectral-domain optical coherence tomography (SD-OCT) volumes, no approaches have been reported for the simultaneous segmentation of these structures within both modalities combined. In this work, a multimodal pixel-classification approach for the segmentation of the optic disc and cup within fundus photographs and SD-OCT volumes is presented. In particular, after segmentation of other important structures (such as the retinal layers and retinal blood vessels) and fundus-to-SD-OCT image registration, features are extracted from both modalities and a k-nearest-neighbor classification approach is used to classify each pixel as cup, rim, or background. The approach is evaluated on 70 multimodal image pairs from 35 subjects in a leave-10%-out fashion (by subject). A significant improvement in classification accuracy is obtained using the multimodal approach over that obtained from the corresponding unimodal approach (97.8% versus 95.2%; p < 0:05; paired t-test).

  9. Automated segmentation of serous pigment epithelium detachment in SD-OCT images

    NASA Astrophysics Data System (ADS)

    Sun, Zhuli; Shi, Fei; Xiang, Dehui; Chen, Haoyu; Chen, Xinjian

    2015-03-01

    Pigment epithelium detachment (PED) is an important clinical manifestation of multiple chorio-retinal disease processes, which can cause the loss of central vision. A 3-D method is proposed to automatically segment serous PED in SD-OCT images. The proposed method consists of five steps: first, a curvature anisotropic diffusion filter is applied to remove speckle noise. Second, the graph search method is applied for abnormal retinal layer segmentation associated with retinal pigment epithelium (RPE) deformation. During this process, Bruch's membrane, which doesn't show in the SD-OCT images, is estimated with the convex hull algorithm. Third, the foreground and background seeds are automatically obtained from retinal layer segmentation result. Fourth, the serous PED is segmented based on the graph cut method. Finally, a post-processing step is applied to remove false positive regions based on mathematical morphology. The proposed method was tested on 20 SD-OCT volumes from 20 patients diagnosed with serous PED. The average true positive volume fraction (TPVF), false positive volume fraction (FPVF), dice similarity coefficient (DSC) and positive predictive value (PPV) are 97.19%, 0.03%, 96.34% and 95.59%, respectively. Linear regression analysis shows a strong correlation (r = 0.975) comparing the segmented PED volumes with the ground truth labeled by an ophthalmology expert. The proposed method can provide clinicians with accurate quantitative information, including shape, size and position of the PED regions, which can assist diagnose and treatment.

  10. Variable Effect of P2Y12 Inhibition on Platelet Thrombus Volume in Flowing Blood

    PubMed Central

    Mendolicchio, G. L.; Zavalloni, D.; Bacci, M.; Corrada, E.; Marconi, M.; Lodigiani, C.; Presbitero, P.; Rota, L.; Ruggeri, Z. M.

    2010-01-01

    Background and objectives Patients treated by percutaneous coronary intervention (PCI) receive aspirin and P2Y12 ADP receptor inhibitors to reduce thrombotic complications. The choice of methodology for monitoring the effects of treatment and assessing its efficacy is still a topic of debate. We evaluated how decreased P2Y12 function influences platelet aggregate (thrombus) size measured ex vivo. Methods and Results We used confocal videomicroscopy to measure in real time the volume of platelet thrombi forming upon blood perfusion over fibrillar collagen type I at the wall shear rate of 1,500 s−1. The average volume was significantly smaller in 31 patients receiving aspirin and clopidogrel (19) or ticlopidine (12) than 21 controls, but individual values were above the lower limit of the normal distribution, albeit mostly within the lower quartile, in 61.3% of cases. Disaggregation of platelet thrombi at later perfusion times occurred frequently in the patients. Vasodilator-stimulated phosphoprotein (VASP) phosphorylation, reflecting P2Y12 inhibition, was also decreased in the patient group and only 22.6% of individual values were above the lower normal limit. We found no correlation between thrombus volume formed onto collagen fibrils and level of P2Y12 inhibition, suggesting that additional and individually variable factors can influence the inhibitory effect of treatment on platelet function. Conclusions Measuring platelet thrombus formation in flowing blood reflects the consequences of anti-platelet therapy in a manner that is not proportional to P2Y12 inhibition. Combining the results of the two assays may improve the assessment of thrombotic risk. PMID:21083646

  11. Geology of the USW SD-7 drill hole Yucca Mountain, Nevada

    SciTech Connect

    Rautman, C.A.; Engstrom, D.A.

    1996-09-01

    The USW SD-7 drill hole is one of several holes drilled under Site Characterization Plan Study 8.3.1.4.3.1, also known as the Systematic Drilling Program, as part of the U.S. Department of Energy characterization program at Yucca Mountain, Nevada. The Yucca Mountain site has been proposed as the potential location of a repository for high-level nuclear waste. The SD-7 drill hole is located near the southern end of the potential repository area and immediately to the west of the Main Test Level drift of the Exploratory Studies Facility. The hole is not far from the junction of the Main Test Level drift and the proposed South Ramp decline. Drill hole USW SD-7 is 2675.1 ft (815.3 m) deep, and the core recovered nearly complete sections of ash-flow tuffs belonging to the lower half of the Tiva Canyon Tuff, the Pah Canyon Tuff, and the Topopah Spring Tuff, all of which are part of the Miocene Paintbrush Group. Core was recovered from much of the underlying Calico Hills Formation, and core was virtually continuous in the Prow Pass Tuff and the Bullfrog Tuff. The SD-7 drill hole penetrated the top several tens of feet into the Tram Tuff, which underlies the Prow Pass and Bullfrog Tuffs. These latter three units are all formations of the Crater Flat Group, The drill hole was collared in welded materials assigned to the crystal-poor middle nonlithophysal zone of the Tiva Canyon Tuff; approximately 280 ft (85 m) of this ash-flow sheet was penetrated by the hole. The Yucca Mountain Tuff appears to be missing from the section at the USW SD-7 location, and the Pah Canyon Tuff is only 14.5 ft thick. The Pah Canyon Tuff was not recovered in core because of drilling difficulties, suggesting that the unit is entirely nonwelded. The presence of this unit is inferred through interpretation of down-hole geophysical logs.

  12. Chronic inflammatory pain upregulates expression of P2Y2 receptor in small-diameter sensory neurons.

    PubMed

    Zhu, Huiqin; Yu, Yi; Zheng, Lingyan; Wang, Lu; Li, Chenli; Yu, Jiangyuan; Wei, Jing; Wang, Chuang; Zhang, Junfang; Xu, Shujun; Wei, Xiaofei; Cui, Wei; Wang, Qinwen; Chen, Xiaowei

    2015-12-01

    Roles of ionotropic purinergic (P2X) receptors in chronic pain have been intensively investigated. However, the contribution of metabotropic purinergic (P2Y) receptors to pathological pain is controversial. In the present study, using single cell RT-PCR (reverse transcription-polymerase chain reaction) and single cell nested-PCR techniques, we examined the expression of P2X(2), P2X(3), P2Y(1) and P2Y(2) mRNA transcripts in retrogradely labeled cutaneous sensory neurons from mouse lumber dorsal root ganglia (DRGs) following peripheral inflammation. The percentage of cutaneous sensory neurons expressing P2Y(2) mRNA transcripts increased after complete Freund's adjuvant (CFA) treatment. Particularly, the P2Y(2) mRNA transcripts were more frequently detected in small-diameter cutaneous neurons from CFA-treated mice than those from control mice. Coexpression of P2Y(2) and P2X (P2X(2) or P2X(3)) mRNAs was more frequently observed in cutaneous sensory neurons from CFA-treated mice relative to controls. Pain behavioral tests showed that the blockade of P2Y receptors by suramin attenuated mechanical allodynia evoked either by CFA or uridine triphosphate (UTP), an endogenous P2Y(2) and P2Y(4) agonist. These results suggest that chronic inflammatory pain enhances expression of P2Y(2) receptor in peripheral sensory neurons that innervate the injured tissue and the activation of P2Y receptors contributes to mechanical allodynia following inflammation. PMID:26062804

  13. The influence of P2Y12 receptor deficiency on the platelet inhibitory activities of prasugrel in a mouse model: evidence for specific inhibition of P2Y12 receptors by prasugrel.

    PubMed

    Hashimoto, Masami; Sugidachi, Atsuhiro; Isobe, Takashi; Niitsu, Yoichi; Ogawa, Taketoshi; Jakubowski, Joseph A; Asai, Fumitoshi

    2007-10-01

    Prasugrel is a novel orally active thienopyridine with faster, higher and more reliable inhibition of platelet aggregation than clopidogrel reflecting its metabolism in vivo to an active metabolite with selective P2Y(12) antagonistic activity. Several lines of evidence support the contention that prasugrel provides selective P2Y(12) receptor antagonistic activity. To date, however, direct evidence of P2Y(12) specific action by prasugrel in vivo is limited. In the present study, effects of prasugrel on ex vivo platelet aggregation were examined in wild type (WT) and P2Y(12)(-/-) mice. In WT mice, prasugrel showed platelet inhibition that was 8.2 times more potent than clopidogrel. In P2Y(12)(-/-) mice, ADP induced platelet aggregation was minimal, and its extent was similar to that in prasugrel-treated WT mice. In addition, no further inhibition of platelet aggregation was observed after administration of prasugrel to P2Y(12)(-/-) mice. Furthermore, prasugrel-treated WT mice showed similar aggregation patterns using collagen- and murine PAR-4 agonist peptide to those of P2Y(12)(-/-) mice treated with vehicle or prasugrel. Overall, these results clearly provide additional in vivo evidence that prasugrel has selective P2Y(12) antagonistic activity. PMID:17681285

  14. 40 CFR Table 28 to Subpart G of... - Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 9 2011-07-01 2011-07-01 false Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks 28 Table 28 to Subpart G of Part 63 Protection of Environment ENVIRONMENTAL... (SD) for Internal Floating Roof Tanks Deck construction Typical deck seam length factor...

  15. Complete Genome Sequence of Geobacter anodireducens SD-1T, a Salt-Tolerant Exoelectrogenic Microbe in Bioelectrochemical Systems.

    PubMed

    Sun, Dan; Cheng, Shaoan; Wang, Aijie; Huang, Fangliang; Liu, Wenzong; Xia, Xue

    2016-01-01

    Strain SD-1 is the type strain of the species Geobacter anodireducens, which was originally isolated from a microbial fuel cell reactor in the United States. The characteristic of this bacterium is its high electrochemical activity. Here, we report the fully assembled genome and plasmid sequence of G. anodireducens SD-1(T). PMID:27257213

  16. Complete Genome Sequence of Geobacter anodireducens SD-1T, a Salt-Tolerant Exoelectrogenic Microbe in Bioelectrochemical Systems

    PubMed Central

    Wang, Aijie; Huang, Fangliang; Liu, Wenzong; Xia, Xue

    2016-01-01

    Strain SD-1 is the type strain of the species Geobacter anodireducens, which was originally isolated from a microbial fuel cell reactor in the United States. The characteristic of this bacterium is its high electrochemical activity. Here, we report the fully assembled genome and plasmid sequence of G. anodireducens SD-1T. PMID:27257213

  17. 40 CFR Table 28 to Subpart G of... - Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 10 2012-07-01 2012-07-01 false Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks 28 Table 28 to Subpart G of Part 63 Protection of Environment ENVIRONMENTAL... (SD) for Internal Floating Roof Tanks Deck construction Typical deck seam length factor...

  18. 40 CFR Table 28 to Subpart G of... - Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 10 2014-07-01 2014-07-01 false Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks 28 Table 28 to Subpart G of Part 63 Protection of Environment ENVIRONMENTAL... (SD) for Internal Floating Roof Tanks Deck construction Typical deck seam length factor...

  19. 40 CFR Table 28 to Subpart G of... - Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 10 2013-07-01 2013-07-01 false Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks 28 Table 28 to Subpart G of Part 63 Protection of Environment ENVIRONMENTAL... (SD) for Internal Floating Roof Tanks Deck construction Typical deck seam length factor...

  20. 40 CFR Table 28 to Subpart G of... - Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks 28 Table 28 to Subpart G of Part 63 Protection of Environment ENVIRONMENTAL... (SD) for Internal Floating Roof Tanks Deck construction Typical deck seam length factor...

  1. Energy of vacancy migration in 0.06C-16Cr-15Ni-2Mo-2Mn-Ti-Si-V-B and 0.07C-16Cr-19Ni-2Mo-2Mn-Ti-Si-V-P-B cladding steels

    NASA Astrophysics Data System (ADS)

    Kozlov, A. V.; Portnykh, I. A.; Tselishchev, A. V.; Shilo, O. B.; Asiptsov, O. I.

    2014-05-01

    Samples of 0.06C-16Cr-15Ni-2Mo-2Mn-Ti-Si-V-B and 0.07C-16Cr-19Ni-2Mo-2Mn-Ti-Si-V-P-B steels (ChS68 and EK164 steels, respectively) in the form of fuel element cladding tubes from a BN-600 reactor have been subjected to neutron irradiation in an IVV-2M research reactor to damage doses of 0.0015, 0.0050, and 0.0100 dpa at a temperature of 30°C. Based on a comparison of the results of dilatometric measurements of the irradiated samples and the samples in the initial state, the energies of vacancy migration in the steels are calculated. It is found that the energy of vacancy migration is 1.08 ± 0.02 eV in the ChS68 steel and 0.98 ± 0.02 eV in the EK164 steel. Using these values, the steady-state vacancy concentrations during irradiation of these steels in the BN-600 reactor are calculated. It is shown that the steady-state vacancy concentration in the EK164 fuel cladding portions irradiated in the lower half of the core is significantly lower than that in the ChS68 cladding. This is a cause of the higher resistance of the former steel to radiation-induced swelling as compared to that of the ChS68 steel upon irradiation in fast neutron breeders.

  2. Activation of P2Y1 and P2Y2 nucleotide receptors by adenosine 5′-triphosphate analogues augmented nerve-mediated relaxation of human corpus cavernosum

    PubMed Central

    Gur, Serap; Hellstrom, Wayne J.G.

    2009-01-01

    Introduction Adenosine 5′-triphosphate (ATP) is a ubiquitous cellular energy source. We evaluated the effect of ATP and its analogues on nonadrenergic and noncholinergic relaxation in precontracted human corpus cavernosal smooth muscle (HCCSM). Methods We obtained specimens of human corpus cavernosum (HCC) from patients undergoing penile prosthesis surgery (patient age 46–70 yr, n = 17) with prior approval from the local institutional review board. Isolated HCC strips were placed in organ baths containing Krebs solution and functional experiments were conducted. Immunohistochemical localization studies were performed to establish the presence of purinergic P2X1, P2Y1 and P2Y2 receptors in HCC. Results The amplitude of relaxation induced by electrical-field stimulation (EFS) on HCC was significantly increased after exposure to ATP (P2X and P2Y agonists), 2-MeSATP (P2Y1 agonist), and uridine 5’ triphosphate (P2Y2 agonist), but not α,β-methylene ATP (P2X1 agonist). The P2X1 antagonist pyridoxal-5’-phosphate-6-azophenyl-2’, 4’-disulfonate, and the nonspecific P2Y antagonist, reactive blue 2, did not inhibit the potentiated response of EFS on HCC. Although immunoreactivity for both P2Y1 and P2Y2 receptors was localized abundantly in HCC, there was only low-level immunostaining for the P2X1 receptor. Conclusion These data demonstrate that nerve-mediated relaxation of HCCSM strips precontracted with phenylephrine in organ bath preparations is amplified by stimulating purinergic P2Y1 and P2Y2 receptors. Although nucleotides are important regulators of HCCSM tone, these observations suggest an independent purinergic relaxing mechanism in the HCC, separate from the better known nitrergic system. PMID:19672446

  3. Hierarchical MoS2@MoP core-shell heterojunction electrocatalysts for efficient hydrogen evolution reaction over a broad pH range

    NASA Astrophysics Data System (ADS)

    Wu, Aiping; Tian, Chungui; Yan, Haijing; Jiao, Yanqing; Yan, Qing; Yang, Guoyu; Fu, Honggang

    2016-05-01

    A low-cost catalyst for the hydrogen evolution reaction (HER) over a broad pH range is highly desired to meet the practical needs in different areas. In this study, hierarchical flower-like MoS2@MoP core-shell heterojunctions (HF-MoSP) are designed as a promising catalyst for HER over a broad pH range. The materials are obtained by the controllable phosphidation of the hierarchical MoS2 flower (HF-MoS2) composed of thin silk belt-like sheets. The phosphidation degree, P/S ratio and work function (WF) of HF-MoSP can be tuned easily over broad range by changing the phosphidation temperature. Under optimized condition, HF-MoSP exhibits excellent electrocatalytic activity for HER with a low onset overpotential of 29 mV and η of 108 mV at 10 mA cm-2 in 0.5 M H2SO4 and retains its good activity for 30 h. In addition, the catalyst shows excellent activity in 1 M KOH with an onset overpotential of 42 mV and η of 119 mV at 10 mA cm-2. The catalysts also exhibit obvious activity in neutral, weak acid and weak alkaline conditions. The good performance is relative to the synergy of the MoP shell and MoS2 core and the high WF of HF-MoSP close to Pt, and the large SBET of HF-MoSP benefited from the hierarchical structure. This study represents the construction of the core-shell heterojunction and provides a new way to provide the low-cost and high-performance catalyst for HER.A low-cost catalyst for the hydrogen evolution reaction (HER) over a broad pH range is highly desired to meet the practical needs in different areas. In this study, hierarchical flower-like MoS2@MoP core-shell heterojunctions (HF-MoSP) are designed as a promising catalyst for HER over a broad pH range. The materials are obtained by the controllable phosphidation of the hierarchical MoS2 flower (HF-MoS2) composed of thin silk belt-like sheets. The phosphidation degree, P/S ratio and work function (WF) of HF-MoSP can be tuned easily over broad range by changing the phosphidation temperature. Under optimized

  4. Thymidine 5'-O-monophosphorothioate induces HeLa cell migration by activation of the P2Y6 receptor.

    PubMed

    Gendaszewska-Darmach, Edyta; Szustak, Marcin

    2016-06-01

    ATP, ADP, UTP, and UDP acting as ligands of specific P2Y receptors activate intracellular signaling cascades to regulate a variety of cellular processes, including proliferation, migration, differentiation, and cell death. Contrary to a widely held opinion, we show here that nucleoside 5'-O-monophosphorothioate analogs, containing a sulfur atom in a place of one nonbridging oxygen atom in a phosphate group, act as ligands for selected P2Y subtypes. We pay particular attention to the unique activity of thymidine 5'-O-monophosphorothioate (TMPS) which acts as a specific partial agonist of the P2Y6 receptor (P2Y6R). We also collected evidence for the involvement of the P2Y6 receptor in human epithelial adenocarcinoma cell line (HeLa) cell migration induced by thymidine 5'-O-monophosphorothioate analog. The stimulatory effect of TMPS was abolished by siRNA-mediated P2Y6 knockdown and diisothiocyanate derivative MRS 2578, a selective antagonist of the P2Y6R. Our results indicate for the first time that increased stability of thymidine 5'-O-monophosphorothioate as well as its affinity toward the P2Y6R may be responsible for some long-term effects mediated by this receptor. PMID:26746211

  5. A novel series of piperazinyl-pyridine ureas as antagonists of the purinergic P2Y12 receptor.

    PubMed

    Bach, Peter; Boström, Jonas; Brickmann, Kay; van Giezen, J J J; Hovland, Ragnar; Petersson, Annika U; Ray, Asim; Zetterberg, Fredrik

    2011-05-15

    A novel series of P2Y(12) antagonists for development of drugs within the antiplatelet area is presented. The synthesis of the piperazinyl-pyridine urea derivatives and their structure-activity relationships (SAR) are described. Several compounds showed P2Y(12) antagonistic activities in the sub-micromolar range. PMID:21507636

  6. Crystal structures of spinel-type Na2MoO4 and Na2WO4 revisited using neutron powder diffraction.

    PubMed

    Fortes, A Dominic

    2015-06-01

    Time-of-flight neutron powder diffraction data have been collected from Na2MoO4 and Na2WO4 to a resolution of sin (θ)/λ = 1.25 Å(-1), which is substanti-ally better than the previous analyses using Mo Kα X-rays, providing roughly triple the number of measured reflections with respect to the previous studies [Okada et al. (1974 ▶). Acta Cryst. B30, 1872-1873; Bramnik & Ehrenberg (2004 ▶). Z. Anorg. Allg. Chem. 630, 1336-1341]. The unit-cell parameters are in excellent agreement with literature data [Swanson et al. (1962 ▶). NBS Monograph No. 25, sect. 1, pp. 46-47] and the structural parameters for the molybdate agree very well with those of Bramnik & Ehrenberg (2004 ▶). However, the tungstate structure refinement of Okada et al. (1974 ▶) stands apart as being conspicuously inaccurate, giving significantly longer W-O distances, 1.819 (8) Å, and shorter Na-O distances, 2.378 (8) Å, than are reported here or in other simple tungstates. As such, this work represents an order-of-magnitude improvement in precision for sodium molybdate and an equally substantial improvement in both accuracy and precision for sodium tungstate. Both compounds adopt the spinel structure type. The Na(+) ions have site symmetry .-3m and are in octa-hedral coordination while the transition metal atoms have site symmetry -43m and are in tetra-hedral coordination. PMID:26090129

  7. Processing of Mo-Si-B intermetallics by extrusion and oxidation properties of the extruded Tl-MoSi{sub 2}-MoB System

    SciTech Connect

    Summers, Eric

    1999-11-08

    An extrusion process was developed that is able to consistently produce large quantities of Mo-Si-B rods without the presence of defects. Binder removal from the extruded rods was studied in detail and it was determined that heating rates on the order of 0.02{degree}/minute (1.2{degree}/hour) are necessary to remove the binder without the formation of defects. This low heating rate resulted in debinding times in excess of 70 hours (approximately 3 days). Wicking was investigated as a means to decrease the time necessary for binder removal. Using 0.05{micro}m alumina powder as a wicking agent, binder removal times were reduced to 10 hours with heating rates up to 1{degree}/minute employed without defect formation. Once the extrusion process was complete the oxidation properties of the Tl-MoSi{sub 2}-MoB extruded phase assemblage was investigated. It was determined that this composition exhibits catastrophic oxidation or pesting in the temperature range of 660--760 C, resulting in the material turning to dust. Outside of this temperature range the composition is oxidatively stable. Continuous mass measurements were taken at 1,300, 1,450, and 1,600 C to determine the oxidation rate constants of this material. Parabolic rate constants of 6.9 x 10{sup {minus}3}, 1.3 x 10{sup {minus}3}, and 9.1 x 10{sup {minus}3} mg{sup 2}/cm{sup 4}/hr were determined for 1,300, 1,450, and 1,600 C respectively.

  8. Hierarchical MoS2@MoP core-shell heterojunction electrocatalysts for efficient hydrogen evolution reaction over a broad pH range.

    PubMed

    Wu, Aiping; Tian, Chungui; Yan, Haijing; Jiao, Yanqing; Yan, Qing; Yang, Guoyu; Fu, Honggang

    2016-06-01

    A low-cost catalyst for the hydrogen evolution reaction (HER) over a broad pH range is highly desired to meet the practical needs in different areas. In this study, hierarchical flower-like MoS2@MoP core-shell heterojunctions (HF-MoSP) are designed as a promising catalyst for HER over a broad pH range. The materials are obtained by the controllable phosphidation of the hierarchical MoS2 flower (HF-MoS2) composed of thin silk belt-like sheets. The phosphidation degree, P/S ratio and work function (WF) of HF-MoSP can be tuned easily over broad range by changing the phosphidation temperature. Under optimized condition, HF-MoSP exhibits excellent electrocatalytic activity for HER with a low onset overpotential of 29 mV and η of 108 mV at 10 mA cm(-2) in 0.5 M H2SO4 and retains its good activity for 30 h. In addition, the catalyst shows excellent activity in 1 M KOH with an onset overpotential of 42 mV and η of 119 mV at 10 mA cm(-2). The catalysts also exhibit obvious activity in neutral, weak acid and weak alkaline conditions. The good performance is relative to the synergy of the MoP shell and MoS2 core and the high WF of HF-MoSP close to Pt, and the large SBET of HF-MoSP benefited from the hierarchical structure. This study represents the construction of the core-shell heterojunction and provides a new way to provide the low-cost and high-performance catalyst for HER. PMID:27172989

  9. Effect of micro-alloy elements (Ti, Nb, Al and Ca) on corrosion resistance of 26%Cr-2%Mo stainless steel in chloride solutions

    SciTech Connect

    Kim, H.; Lee, Y.D.

    1999-11-01

    Ferritic stainless steels have higher corrosion and stress corrosion cracking resistance in chloride environments than austenitic stainless steels. The production mat of ferritic stainless steels is lower than austenitic stainless steels. However, the application of highly alloyed ferritic stainless steels is limited due to low toughness and intergranular corrosion attack. Corrosion resistance of 26%Cr-2%Mo ferritic steels was evaluated using polarization test in 20% NaCl solution and the ferric chloride test. In addition, TEM and SEM were employed to analyze the secondary phases around the matrix where pitting corrosion occurred. In ferric chloride test the crevice corrosion resistance of non-stabilized alloy and Ca added alloy was lower than that of stabilized alloy and the crevice corrosion resistance of stabilized alloys was independent of stabilizing element such as Ti and Nb. The pitting corrosion resistance in chloride solution depended on micro-alloying elements as well as the surface treatment such as pickling and polishing. The effect of micro-alloy element and surface treatment on corrosion properties was explained with the aid of SEM observations. Among the polished alloys, the addition of Nb was the most effective for pitting corrosion resistance but the addition of Ti or Ca decreased the corrosion resistance. The pickling increased the corrosion resistance in all alloys except alloy No. 4 (Ti + Nb + Al). Pickling effectively increased corrosion resistance of the alloy containing Ti or Ca, due to removal of pit initiation sites associated with TiN inclusions or unstable phase (i.e., CaS, TiN).

  10. Crystal structures of spinel-type Na2MoO4 and Na2WO4 revisited using neutron powder diffraction

    PubMed Central

    Fortes, A. Dominic

    2015-01-01

    Time-of-flight neutron powder diffraction data have been collected from Na2MoO4 and Na2WO4 to a resolution of sin (θ)/λ = 1.25 Å−1, which is substanti­ally better than the previous analyses using Mo Kα X-rays, providing roughly triple the number of measured reflections with respect to the previous studies [Okada et al. (1974 ▸). Acta Cryst. B30, 1872–1873; Bramnik & Ehrenberg (2004 ▸). Z. Anorg. Allg. Chem. 630, 1336–1341]. The unit-cell parameters are in excellent agreement with literature data [Swanson et al. (1962 ▸). NBS Monograph No. 25, sect. 1, pp. 46–47] and the structural parameters for the molybdate agree very well with those of Bramnik & Ehrenberg (2004 ▸). However, the tungstate structure refinement of Okada et al. (1974 ▸) stands apart as being conspicuously inaccurate, giving significantly longer W—O distances, 1.819 (8) Å, and shorter Na—O distances, 2.378 (8) Å, than are reported here or in other simple tungstates. As such, this work represents an order-of-magnitude improvement in precision for sodium molybdate and an equally substantial improvement in both accuracy and precision for sodium tungstate. Both compounds adopt the spinel structure type. The Na+ ions have site symmetry .-3m and are in octa­hedral coordination while the transition metal atoms have site symmetry -43m and are in tetra­hedral coordination. PMID:26090129

  11. Reaction mechanism of core–shell MoO2/MoS2 nanoflakes via plasma-assisted sulfurization of MoO3

    NASA Astrophysics Data System (ADS)

    Kumar, Prabhat; Singh, Megha; Sharma, Rabindar K.; Reddy, G. B.

    2016-05-01

    The sulfurization of MoO3 in an H2S/Ar plasma atmosphere has been experimentally studied and a reaction mechanism has been proposed based on the results obtained. Nanostructured thin films (NTFs) of MoO3 were sulfurized at different temperatures varying from 150 °C to 550 °C. High-resolution transmission electron microscopy (TEM) images depict core–shell nanoflakes with varying shell thicknesses as the sulfurization temperature (T sn) is varied. The shells consist of MoS2 and the core is MoO2/MoO3. X-ray diffraction (XRD) and Raman analysis have been used to study the structural changes as MoO3 is sulfurized. The analyses showed two phases, MoO2 and MoS2, at low temperatures (≤350 °C), whereas the films sulfurized at higher temperatures show predominantly MoS2. The scanning electron microscopy (SEM) results show no noticeable changes in the surface morphology of the NTFs after sulfurization. X-ray photoelectron spectroscopy (XPS) was carried out to calculate the relative percentages of MoO3, MoO2 and MoS2. It is revealed that sulfurization of MoO3 in the plasma is affected by T sn. The sulfurization process occurs in two steps, involving the reduction of MoO3 to form MoO2 in the first step, followed by MoO2 being converted into MoS2. It is also evident that the reduction of MoO3 is more a result of the reactive species of hydrogen (H*) than the replacement of oxygen by sulfur in the second step.

  12. Plasmodium falciparum Rosetting Epitopes Converge in the SD3-Loop of PfEMP1-DBL1α

    PubMed Central

    Angeletti, Davide; Albrecht, Letusa; Blomqvist, Karin; Quintana, María del Pilar; Akhter, Tahmina; Bächle, Susanna M.; Sawyer, Alan; Sandalova, Tatyana; Achour, Adnane; Wahlgren, Mats; Moll, Kirsten

    2012-01-01

    The ability of Plasmodium falciparum parasitized RBC (pRBC) to form rosettes with normal RBC is linked to the virulence of the parasite and RBC polymorphisms that weaken rosetting confer protection against severe malaria. The adhesin PfEMP1 mediates the binding and specific antibodies prevent sequestration in the micro-vasculature, as seen in animal models. Here we demonstrate that epitopes targeted by rosette disrupting antibodies converge in the loop of subdomain 3 (SD3) which connects the h6 and h7 α-helices of PfEMP1-DBL1α. Both monoclonal antibodies and polyclonal IgG, that bound to epitopes in the SD3-loop, stained the surface of pRBC, disrupted rosettes and blocked direct binding of recombinant NTS-DBL1α to RBC. Depletion of polyclonal IgG raised to NTS-DBL1α on a SD3 loop-peptide removed the anti-rosetting activity. Immunizations with recombinant subdomain 1 (SD1), subdomain 2 (SD2) or SD3 all generated antibodies reacting with the pRBC-surface but only the sera of animals immunized with SD3 disrupted rosettes. SD3-sequences were found to segregate phylogenetically into two groups (A/B). Group A included rosetting sequences that were associated with two cysteine-residues present in the SD2-domain while group B included those with three or more cysteines. Our results suggest that the SD3 loop of PfEMP1-DBL1α is an important target of anti-rosetting activity, clarifying the molecular basis of the development of variant-specific rosette disrupting antibodies. PMID:23227205

  13. P2Y13 receptors mediate presynaptic inhibition of acetylcholine release induced by adenine nucleotides at the mouse neuromuscular junction.

    PubMed

    Guarracino, Juan F; Cinalli, Alejandro R; Fernández, Verónica; Roquel, Liliana I; Losavio, Adriana S

    2016-06-21

    It is known that adenosine 5'-triphosphate (ATP) is released along with the neurotransmitter acetylcholine (ACh) from motor nerve terminals. At mammalian neuromuscular junctions (NMJs), we have previously demonstrated that ATP is able to decrease ACh secretion by activation of P2Y receptors coupled to pertussis toxin-sensitive Gi/o protein. In this group, the receptor subtypes activated by adenine nucleotides are P2Y12 and P2Y13. Here, we investigated, by means of pharmacological and immunohistochemical assays, the P2Y receptor subtype that mediates the modulation of spontaneous and evoked ACh release in mouse phrenic nerve-diaphragm preparations. First, we confirmed that the preferential agonist for P2Y12-13 receptors, 2-methylthioadenosine 5'-diphosphate trisodium salt hydrate (2-MeSADP), reduced MEPP frequency without affecting MEPP amplitude as well as the amplitude and quantal content of end-plate potentials (EPPs). The effect on spontaneous secretion disappeared after the application of the selective P2Y12-13 antagonists AR-C69931MX or 2-methylthioadenosine 5'-monophosphate triethylammonium salt hydrate (2-MeSAMP). 2-MeSADP was more potent than ADP and ATP in reducing MEPP frequency. Then we demonstrated that the selective P2Y13 antagonist MRS-2211 completely prevented the inhibitory effect of 2-MeSADP on MEPP frequency and EPP amplitude, whereas the P2Y12 antagonist MRS-2395 failed to do this. The preferential agonist for P2Y13 receptors inosine 5'-diphosphate sodium salt (IDP) reduced spontaneous and evoked ACh secretion and MRS-2211 abolished IDP-mediated modulation. Immunohistochemical studies confirmed the presence of P2Y13 but not P2Y12 receptors at the end-plate region. Disappearance of P2Y13 receptors after denervation suggests the presynaptic localization of the receptors. We conclude that, at motor nerve terminals, the Gi/o protein-coupled P2Y receptors implicated in presynaptic inhibition of spontaneous and evoked ACh release are of the subtype P2Y

  14. Expression of the P2Y6 purinergic receptor in human T cells infiltrating inflammatory bowel disease.

    PubMed

    Somers, G R; Hammet, F M; Trute, L; Southey, M C; Venter, D J

    1998-11-01

    The human P2Y6 receptor is a member of the G-protein-coupled P2Y purinergic receptor family that responds to extracellular uridine diphosphate (UDP). In previous work, we cloned the human P2Y6 receptor from an activated T-cell library, and others have shown that it is expressed as a 1.9-kb transcript in several lymphoid tissues. This suggests a role for P2Y6 in T-cell function. However, the precise cellular expression pattern and regulation of P2Y6 in immune cells have not yet been established. In this study, we have examined the expression of P2Y6 in a range of tissues containing leukocytes by a combination of in situ hybridization (ISH), Northern blot analysis, and RT-PCR. Northern hybridization revealed that activated peripheral T cells show increased levels of P2Y6 mRNA. Furthermore, RT-PCR analysis of CD4+ and CD8+ subsets illustrated strong expression in both activated CD4+ and CD8+ T cells. Stimulation of resting and activated T cells with the P2Y6 ligand UDP caused a rise in the intracellular free calcium concentration in only the activated subset, indicating the presence of functional receptor. By ISH, P2Y6 expression was detected in the T cells of the thymic medulla and spleen, whereas no signal was detected in the bone marrow, fetal liver, or lymph nodes. T cells are thought to play an important role in the pathogenesis of inflammatory bowel disease (IBD), and because a recent finding has suggested a role for extracellular nucleotides in mediating colonic epithelial cell damage in IBD, we speculated that the P2Y6 nucleotide receptor may be expressed in the T cells infiltrating IBD. ISH results reveal that P2Y6 is highly expressed in the T cells infiltrating active IBD, whereas P2Y6 expression was absent from the T cells of unaffected bowel. These results demonstrate expression and regulation of P2Y6 expression in T cells, and suggest a role for P2Y6 in the pathogenesis of IBD-mediated intestinal damage. PMID:9840612

  15. Correlation between SD-OCT, immunocytochemistry and functional findings in an animal model of retinal degeneration

    PubMed Central

    Cuenca, Nicolás; Fernández-Sánchez, Laura; Sauvé, Yves; Segura, Francisco J.; Martínez-Navarrete, Gema; Tamarit, José Manuel; Fuentes-Broto, Lorena; Sanchez-Cano, Ana; Pinilla, Isabel

    2014-01-01

    Purpose: The P23H rhodopsin mutation is an autosomal dominant cause of retinitis pigmentosa (RP). The degeneration can be tracked using different anatomical and functional methods. In our case, we evaluated the anatomical changes using Spectral-Domain Optical Coherence Tomography (SD-OCT) and correlated the findings with retinal thickness values determined by immunocytochemistry.Methods: Pigmented rats heterozygous for the P23H mutation, with ages between P18 and P180 were studied. Function was assessed by means of optomotor testing and ERGs. Retinal thicknesses measurements, autofluorescence and fluorescein angiography were performed using Spectralis OCT. Retinas were studied by means of immunohistochemistry. Results: Between P30 and P180, visual acuity decreased from 0.500 to 0.182 cycles per degree (cyc/deg) and contrast sensitivity decreased from 54.56 to 2.98 for a spatial frequency of 0.089 cyc/deg. Only cone-driven b-wave responses reached developmental maturity. Flicker fusions were also comparable at P29 (42 Hz). Double flash-isolated rod-driven responses were already affected at P29. Photopic responses revealed deterioration after P29.A reduction in retinal thicknesses and morphological modifications were seen in OCT sections. Statistically significant differences were found in all evaluated thicknesses. Autofluorescence was seen in P23H rats as sparse dots. Immunocytochemistry showed a progressive decrease in the outer nuclear layer (ONL), and morphological changes. Although anatomical thickness measures were significantly lower than OCT values, there was a very strong correlation between the values measured by both techniques.Conclusions: In pigmented P23H rats, a progressive deterioration occurs in both retinal function and anatomy. Anatomical changes can be effectively evaluated using SD-OCT and immunocytochemistry, with a good correlation between their values, thus making SD-OCT an important tool for research in retinal degeneration. PMID:25565976

  16. A complex noise reduction method for improving visualization of SD-OCT skin biomedical images

    NASA Astrophysics Data System (ADS)

    Myakinin, Oleg O.; Zakharov, Valery P.; Bratchenko, Ivan A.; Kornilin, Dmitry V.; Khramov, Alexander G.

    2014-05-01

    In this paper we consider the original method of solving noise reduction problem for visualization's quality improvement of SD-OCT skin and tumors biomedical images. The principal advantages of OCT are high resolution and possibility of in vivo analysis. We propose a two-stage algorithm: 1) process of raw one-dimensional A-scans of SD-OCT and 2) remove a noise from the resulting B(C)-scans. The general mathematical methods of SD-OCT are unstable: if the noise of the CCD is 1.6% of the dynamic range then result distortions are already 25-40% of the dynamic range. We use at the first stage a resampling of A-scans and simple linear filters to reduce the amount of data and remove the noise of the CCD camera. The efficiency, improving productivity and conservation of the axial resolution when using this approach are showed. At the second stage we use an effective algorithms based on Hilbert-Huang Transform for more accurately noise peaks removal. The effectiveness of the proposed approach for visualization of malignant and benign skin tumors (melanoma, BCC etc.) and a significant improvement of SNR level for different methods of noise reduction are showed. Also in this study we consider a modification of this method depending of a specific hardware and software features of used OCT setup. The basic version does not require any hardware modifications of existing equipment. The effectiveness of proposed method for 3D visualization of tissues can simplify medical diagnosis in oncology.

  17. The Mysterious sdO X-ray Binary BD+37°442

    NASA Astrophysics Data System (ADS)

    Heber, U.; Geier, S.; Irrgang, A.; Schneider, D.; Barbu-Barna, I.; Mereghetti, S.; La Palombara, N.

    2014-04-01

    Pulsed X-ray emission in the luminous, helium-rich sdO BD +37°442 has recently been discovered (La Palombara et al. 2012). It was suggested that the sdO star has a neutron star or white dwarf companion with a spin period of 19.2 s. After HD 49798, which has a massive white dwarf companion spinning at 13.2 s in an 1.55 day orbit, this is only the second O-type subdwarf from which X-ray emission has been detected. We report preliminary results of our ongoing campaign to obtain time-resolved high-resolution spectroscopy using the CAFE instrument at Calar Alto observatory and SARG at the Telescopio Nationale Galileo. Atmospheric parameters were derived via a quantitative NLTE spectral analysis. The line fits hint at an unusually large projected rotation velocity. Therefore it seemed likely that BD +37°442 is a binary similar to HD 49798 and that the orbital period is also similar. The level of X-ray emission from BD +37°442 could be explained by accretion from the sdO wind by a neutron star orbiting at a period of less than ten days. Hence, we embarked on radial velocity monitoring in order to derive the binary parameters of the BD+37°442 system and obtained 41 spectra spread out over several month in 2012. Unlike for HD 49798, no radial velocity variations were found and, hence, there is no dynamical evidence for the existence of a compact companion yet. The origin of the pulsed X-ray emission remains as a mystery.

  18. Identification of Determinants Required for Agonistic and Inverse Agonistic Ligand Properties at the ADP Receptor P2Y12

    PubMed Central

    Schmidt, Philipp; Ritscher, Lars; Dong, Elizabeth N.; Hermsdorf, Thomas; Cöster, Maxi; Wittkopf, Doreen; Meiler, Jens

    2013-01-01

    The ADP receptor P2Y12 belongs to the superfamily of G protein–coupled receptors (GPCRs), and its activation triggers platelet aggregation. Therefore, potent antagonists, such as clopidogrel, are of high clinical relevance in prophylaxis and treatment of thromboembolic events. P2Y12 displays an elevated basal activity in vitro, and as such, inverse agonists may be therapeutically beneficial compared with antagonists. Only a few inverse agonists of P2Y12 have been described. To expand this limited chemical space and improve understanding of structural determinants of inverse agonist-receptor interaction, this study screened a purine compound library for lead structures using wild-type (WT) human P2Y12 and 28 constitutively active mutants. Results showed that ATP and ATP derivatives are agonists at P2Y12. The potency at P2Y12 was 2-(methylthio)-ADP > 2-(methylthio)-ATP > ADP > ATP. Determinants required for agonistic ligand activity were identified. Molecular docking studies revealed a binding pocket for the ATP derivatives that is bordered by transmembrane helices 3, 5, 6, and 7 in human P2Y12, with Y105, E188, R256, Y259, and K280 playing a particularly important role in ligand interaction. N-Methyl-anthraniloyl modification at the 3′-OH of the 2′-deoxyribose leads to ligands (mant-deoxy-ATP [dATP], mant-deoxy-ADP) with inverse agonist activity. Inverse agonist activity of mant-dATP was found at the WT human P2Y12 and half of the constitutive active P2Y12 mutants. This study showed that, in addition to ADP and ATP, other ATP derivatives are not only ligands of P2Y12 but also agonists. Modification of the ribose within ATP can result in inverse activity of ATP-derived ligands. PMID:23093496

  19. The orbital periods of three sdB eclipsing binary systems

    NASA Astrophysics Data System (ADS)

    Kilkenny, D.

    2014-12-01

    Recent timings of eclipses made between 2011 and 2014 are presented for three binary systems with hot subdwarf primary stars, AA Dor, NY Vir and EC 10246-2707. In the case of AA Dor, the period remains constant. In NY Vir, a rapidly pulsating sdBVr with a cool companion, the period change now appears more complex than can be described by a simple quadratic. EC 10246-2707, which has previously appeared to have a constant period, now appears to be showing a significant period increase. The effect of gravitational radiation in HW Vir-like systems is briefly discussed.

  20. EXOTIME: Searching for planets and measuring \\dot{P} in sdB pulsators

    NASA Astrophysics Data System (ADS)

    Lutz, R.; Schuh, S.; Silvotti, R.

    2012-12-01

    We review the status of the EXOTIME project (EXOplanet search with the TIming MEthod). The two main goals of EXOTIME are to search for sub-stellar companions to sdB stars in wide orbits, and to measure the secular variation of the pulsation periods, which are related to the evolutionary change of the stellar structure. Now, after four years of dense monitoring, we start to see some results and present the brown dwarf and exoplanet candidates V1636 Ori b and DW Lyn b.

  1. Clinical outcomes of a 2-y soy isoflavone supplementation in menopausal women1234

    PubMed Central

    Steinberg, Francene M; Murray, Michael J; Lewis, Richard D; Cramer, Margaret A; Amato, Paula; Young, Ronald L; Barnes, Stephen; Konzelmann, Karen L; Fischer, Joan G; Ellis, Kenneth J; Shypailo, Roman J; Fraley, J Kennard; Smith, E O'Brian; Wong, William W

    2011-01-01

    Background: Soy isoflavones are naturally occurring phytochemicals with weak estrogenic cellular effects. Despite numerous clinical trials of short-term isoflavone supplementation, there is a paucity of data regarding longer-term outcomes and safety. Objective: Our aim was to evaluate the clinical outcomes of soy hypocotyl isoflavone supplementation in healthy menopausal women as a secondary outcome of a trial on bone health. Design: A multicenter, randomized, double-blind, placebo-controlled 24-mo trial was conducted to assess the effects of daily supplementation with 80 or 120 mg aglycone equivalent soy hypocotyl isoflavones plus calcium and vitamin D on the health of 403 postmenopausal women. At baseline and after 1 and 2 y, clinical blood chemistry values were measured and a well-woman examination was conducted, which included a mammogram and a Papanicolaou test. A cohort also underwent transvaginal ultrasound measurements to assess endometrial thickness and fibroids. Results: The baseline characteristics of the groups were similar. After 2 y of daily isoflavone exposure, all clinical chemistry values remained within the normal range. The only variable that changed significantly was blood urea nitrogen, which increased significantly after 2 y (P = 0.048) but not after 1 y (P = 0.343) in the supplementation groups. Isoflavone supplementation did not affect blood lymphocyte or serum free thyroxine concentrations. No significant differences in endometrial thickness or fibroids were observed between the groups. Two serious adverse events were detected (one case of breast cancer and one case of estrogen receptor–negative endometrial cancer), which was less than the expected population rate for these cancers. Conclusion: Daily supplementation for 2 y with 80–120 mg soy hypocotyl isoflavones has minimal risk in healthy menopausal women. This trial was registered at clinicaltrials.gov as NCT00665860 PMID:21177797

  2. Novel consequences of voltage-dependence to G-protein-coupled P2Y1 receptors

    PubMed Central

    Gurung, I S; Martinez-Pinna, J; Mahaut-Smith, M P

    2008-01-01

    Background and purpose: Emerging evidence suggests that activation of G-protein-coupled receptors (GPCRs) can be directly regulated by membrane voltage. However, the physiological and pharmacological relevance of this effect remains unclear. We have further examined this phenomenon for P2Y1 receptors in the non-excitable megakaryocyte using a range of agonists and antagonists. Experimental approach: Simultaneous whole-cell patch clamp and fura-2 fluorescence recordings of rat megakaryocytes, which lack voltage-gated Ca2+ influx, were used to examine the voltage-dependence of P2Y1 receptor-evoked IP3-dependent Ca2+ mobilization. Results: Depolarization transiently and repeatedly enhanced P2Y1 receptor-evoked Ca2+ mobilization across a wide concentration range of both weak, partial and full, potent agonists. Moreover, the amplitude of the depolarization-evoked [Ca2+]i increase displayed an inverse relationship with agonist concentration, such that the greatest potentiating effect of voltage was observed at near-threshold levels of agonist. Unexpectedly, depolarization also stimulated an [Ca2+]i increase in the absence of agonist during exposure to the competitive antagonists A3P5PS and MRS2179, or the allosteric enhancer 2,2′-pyridylisatogen tosylate. A further effect of some antagonists, particularly suramin, was to enhance the depolarization-evoked Ca2+ responses during co-application of an agonist. Of several P2Y1 receptor inhibitors, only SCH202676, which has a proposed allosteric mechanism of action, could block ADP-induced voltage-dependent Ca2+ release. Conclusions and implications: The ability of depolarization to potentiate GPCRs at near-threshold agonist concentrations represents a novel mechanism for coincidence detection. Furthermore, the induction and enhancement of voltage-dependent GPCR responses by antagonists has implications for the design of therapeutic compounds. PMID:18414379

  3. On the Diophantine equation x^2+q^2m=2y^p

    NASA Astrophysics Data System (ADS)

    Tengely, Sz

    In this paper we consider the Diophantine equation $x^2+q^{2m}=2y^p$ where $m,p,q,x,y$ are integer unknowns with $m>0,$ $p$ and $q$ are odd primes and $\\gcd(x,y)=1.$ We prove that there are only finitely many solutions $(m,p,q,x,y)$ for which $y$ is not a sum of two consecutive squares. We also study the above equation with fixed $y$ and with fixed $q.$

  4. 6. Credit WCT. Original 21" x 2Y" color negative is ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Credit WCT. Original 2-1" x 2-Y" color negative is housed in the JPL Photography Laboratory, Pasadena, California. JPL staff members Harold Anderson and John Morrow weigh out small amounts of an undetermined substance according to a solid propellant formula (JPL negative no. JPL-10277AC, 27 January 1989). - Jet Propulsion Laboratory Edwards Facility, Weigh & Control Building, Edwards Air Force Base, Boron, Kern County, CA

  5. Nitric Oxide–mediated Modulation of Synaptic Activity by Astrocytic P2Y Receptors

    PubMed Central

    Mehta, Bhupesh; Begum, Gulnaz; Joshi, Nanda B.; Joshi, Preeti G.

    2008-01-01

    We investigated the mechanism of synaptic suppression by P2Y receptors in mixed hippocampal cultures wherein networked neurons exhibit synchronized Ca2+ oscillations (SCO) due to spontaneous glutamatergic synaptic transmission. Pharmacological studies suggested that SCO suppression was mediated by P2Y2/P2Y4 receptors. Immunostaining studies and characterization of ATP/UTP-stimulated Ca2+ responses in solitary neurons and astrocytes revealed that the SCO attenuation was effectuated by astrocytes. We demonstrate that nitric oxide released from activated astrocytes causes synaptic suppression by inhibiting neurotransmitter release. Physiological concentrations of ATP and UTP evoked NO production in astrocytes. SCO suppression was considerably diminished by removal of extracellular NO by membrane-impermeable scavenger c-PTIO or by pretreatment of cells with nitric oxide synthase inhibitor L-NAME. The nitric oxide donor DETA/NO effectively suppressed the SCO. ATP/UTP inhibited KCl-induced exocytosis at presynaptic terminals in an NO-dependent manner. In the absence of exogenously added ATP/UTP, both the NO scavenger and NOS inhibitor enhanced the frequency of SCO, implying that astrocytes release NO during spontaneous synaptic activity and exert a suppressive effect. We report for the first time that under physiological conditions astrocytes use NO as a messenger molecule to modulate the synaptic strength in the networked neurons. PMID:18725529

  6. The role of P2Y1 receptor signaling in central respiratory control.

    PubMed

    Rajani, V; Zhang, Y; Revill, A L; Funk, G D

    2016-06-01

    The profile of P2 receptor signaling in respiratory control has increased substantially since the first suggestions more than 15 years ago of roles in central chemoreception and modulating inspiratory motor outflow. Part of this reflects the paradigm shift that glia participate in information processing and that ATP is a major gliotransmitter. P2 receptors are a diverse family. Here, we review ATP signaling in respiratory control, highlighting G-protein coupled P2Y1 receptors that have been a focus of recent work. Despite strong evidence of a role for glia and P2 receptor signaling in the central chemosensitivity mediated by the retotrapezoid nucleus, P2Y1 receptors do not appear to be directly involved. Evidence that central P2 receptors and glia contribute to the hypoxic ventilatory response is compelling and P2Y1 receptors are the strongest candidate. However, functional significance in vivo, details of the signaling pathways and involvement of other receptor subtypes remain important questions. PMID:26476057

  7. Dependence of steady-state radiation swelling rate of l 0.1C-16Cr-15Ni-2Mo-2Mn-Ti-Si austenitic steel on dpa rate and irradiation temperature

    NASA Astrophysics Data System (ADS)

    Kozlov, А. V.; Portnykh, I. А.

    2009-04-01

    A large number of swelling measurement data on the 0.1C-16Cr-15Ni-2Mo-2Mn-Ti-Si austenitic steel used as a fuel cladding at temperatures 640-870 К in the BN-600 fast reactor were analyzed. It was found that within irradiation temperatures 690-830 К a steady-state swelling dose rate was from 0.45%/dpa to 1.1%/dpa. By the statistical model of point defect migration for the 0.1C-16Cr-15Ni-2Mo-2Mn-Ti-S steel the dependence of the steady-state swelling rate on the irradiation temperature and displacement rate was calculated. The calculation data were consistent with the experimental data.

  8. CysLT1 leukotriene receptor antagonists inhibit the effects of nucleotides acting at P2Y receptors

    PubMed Central

    Mamedova, Liaman; Capra, Valérie; Accomazzo, Maria Rosa; Gao, Zhan-Guo; Ferrario, Silvia; Fumagalli, Marta; Abbracchio, Maria P.; Rovati, G. Enrico; Jacobson, Kenneth A.

    2016-01-01

    Montelukast and pranlukast are orally active leukotriene receptor antagonists selective for the CysLT1 receptor. Conversely, the hP2Y1,2,4,6,11,12,13,14 receptors represent a large family of GPCRs responding to either adenine or uracil nucleotides, or to sugar-nucleotides. Montelukast and pranlukast were found to inhibit nucleotide-induced calcium mobilization in a human monocyte-macrophage like cell line, DMSO-differentiated U937 (dU937). Montelukast and pranlukast inhibited the effects of UTP with IC50 values of 7.7 and 4.3 μM, respectively, and inhibited the effects of UDP with IC50 values of 4.5 and 1.6 μM, respectively, in an insurmountable manner. Furthermore, ligand binding studies using [3H]LTD4 excluded the possibility of orthosteric nucleotide binding to the CysLT1 receptor. dU937 cells were shown to express P2Y2, P2Y4, P2Y6, P2Y11, P2Y13 and P2Y14 receptors. Therefore, these antagonists were studied functionally in a heterologous expression system for the human P2Y receptors. In 1321N1 astrocytoma cells stably expressing human P2Y1,2,4,6 receptors, CysLT1 antagonists inhibited both the P2Y agonist-induced activation of phospholipase C and intracellular Ca2+ mobilization. IC50 values at P2Y1 and P2Y6 receptors were <1 μM. In control astrocytoma cells expressing an endogenous M3 muscarinic receptor, 10 μM montelukast had no effect on the carbachol-induced rise in intracellular Ca2+. These data demonstrated that CysLT1 receptor antagonists interact functionally with signaling pathways of P2Y receptors, and this should foster the study of possible implications for the clinical use of these compounds in asthma or in other inflammatory conditions. PMID:16280122

  9. Origin of Dissimilar Single-Molecule Magnet Behavior of Three MnII(2)MoIII Complexes Based on [MoIII(CN)7]4- Heptacyanomolybdate: Interplay of MoIII-CN-MnII Anisotropic Exchange Interactions.

    PubMed

    Mironov, Vladimir S

    2015-12-01

    The origin of contrasting single-molecule magnet (SMM) behavior of three MnII2MoIII complexes based on [MoIII(CN)7]4– heptacyanomolybdate is analyzed; only the apical Mn2Mo isomer exhibits SMM properties with Ueff = 40.5 cm(-1) and TB = 3.2 K, while the two equatorial isomers are simple paramagnets [Qian, K.; J. Am. Chem. Soc. 2013, 135, 13302]. A microscopic theory of anisotropic spin coupling between orbitally degenerate [MoIII(CN)7](4-) complexes (pentagonal bipyramid) and bound MnII ions is developed. It is shown that the [MoIII(CN)7](4-) complex has a unique property of uniaxial anisotropic spin coupling in the apical and equatorial MoIII-CN-MnII pairs, H̑eff = -Jxy(SMoxSMnx + SMoySMny) - JzSMozSMnz, regardless of their actual low symmetry. The difference in the SMM behavior originates from a different ratio between the anisotropic exchange parameters Jz and Jxy for the apical and equatorial Mo-CN-Mn groups. In the apical Mn2Mo isomer, an Ising-type anisotropic spin coupling (Jz = -34, Jxy = -11 cm(-1)) produces a double-well potential of spin states resulting in SMM behavior. Exchange anisotropy of an xy-type (|Jz| < |Jxy|) in the equatorial Mn2Mo isomers results in a single-well potential with no SMM properties. The prospects of anisotropic uniaxial spin coupling in engineering of high Ueff and TB values are discussed. PMID:26566074

  10. Involvement of Microglial P2Y12 Signaling in Tongue Cancer Pain.

    PubMed

    Tamagawa, T; Shinoda, M; Honda, K; Furukawa, A; Kaji, K; Nagashima, H; Akasaka, R; Chen, J; Sessle, B J; Yonehara, Y; Iwata, K

    2016-09-01

    To elucidate if microglial P2Y12 receptor (P2Y12R) mechanisms are involved in the trigeminal spinal subnucleus caudalis (Vc; also known as the medullary dorsal horn) in intraoral cancer pain, we developed a rat model of tongue cancer pain. Squamous cell carcinoma (SCC) cells were inoculated into the tongue of rats; sham control rats received the vehicle instead. Nociceptive behavior was measured as the head-withdrawal reflex threshold (HWRT) to mechanical or heat stimulation applied to the tongue under light anesthesia. On day 14 after the SCC inoculation, activated microglia and P2Y12R expression were examined immunohistochemically in the Vc. The HWRT was also studied in SCC-inoculated rats with successive intra-cisterna magna (i.c.m.) administration of specific P2Y12R antagonist (MRS2395) or intraperitoneal administration of minocycline, a microglial activation inhibitor. Tongue cancer was histologically verified in SCC-inoculated rats, within which the HWRT to mechanical stimulation of the tongue was significantly decreased, as compared with that of vehicle-inoculated rats, although the HWRT to heat stimulation was not. Microglia was strongly activated on day 14, and the administration of MRS2395 or minocycline reversed associated nocifensive behavior and microglial activation in SCC-inoculated rats for 14 d. The activity of Vc wide dynamic range nociceptive neurons was also recorded electrophysiologically in SCC-inoculated and sham rats. Background activity and noxious mechanically evoked responses of wide dynamic range neurons were significantly increased in SCC-inoculated rats versus sham rats, and background activity and mechanically evoked responses were significantly suppressed following i.c.m. administration of MRS2395 in SCC-inoculated rats as compared with sham. The present findings suggest that SCC inoculation that produces tongue cancer results in strong activation of microglia via P2Y12 signaling in the Vc, in association with increased excitability

  11. Medicinal chemistry of adenosine, P2Y and P2X receptors.

    PubMed

    Jacobson, Kenneth A; Müller, Christa E

    2016-05-01

    Pharmacological tool compounds are now available to define action at the adenosine (ARs), P2Y and P2X receptors. We present a selection of the most commonly used agents to study purines in the nervous system. Some of these compounds, including A1 and A3 AR agonists, P2Y1R and P2Y12R antagonists, and P2X3, P2X4 and P2X7 antagonists, are potentially of clinical use in treatment of disorders of the nervous system, such as chronic pain, neurodegeneration and brain injury. Agonists of the A2AAR and P2Y2R are already used clinically, P2Y12R antagonists are widely used antithrombotics and an antagonist of the A2AAR is approved in Japan for treating Parkinson's disease. The selectivity defined for some of the previously introduced compounds has been revised with updated pharmacological characterization, for example, various AR agonists and antagonists were deemed A1AR or A3AR selective based on human data, but species differences indicated a reduction in selectivity ratios in other species. Also, many of the P2R ligands still lack bioavailability due to charged groups or hydrolytic (either enzymatic or chemical) instability. X-ray crystallographic structures of AR and P2YRs have shifted the mode of ligand discovery to structure-based approaches rather than previous empirical approaches. The X-ray structures can be utilized either for in silico screening of chemically diverse libraries for the discovery of novel ligands or for enhancement of the properties of known ligands by chemical modification. Although X-ray structures of the zebrafish P2X4R have been reported, there is scant structural information about ligand recognition in these trimeric ion channels. In summary, there are definitive, selective agonists and antagonists for all of the ARs and some of the P2YRs; while the pharmacochemistry of P2XRs is still in nascent stages. The therapeutic potential of selectively modulating these receptors is continuing to gain interest in such fields as cancer, inflammation, pain

  12. HS 0705+6700: a New Eclipsing sdB Binary

    NASA Astrophysics Data System (ADS)

    Drechsel, H.; Heber, U.; Napiwotzki, R.; Ostensen, R.; Solheim, J.-E.; Deetjen, J.; Schuh, S.

    HS 0705+6700 is a newly discovered eclipsing sdB binary system consisting of an sdB primary and a cool secondary main sequence star. CCD photometry obtained in October and November 2000 with the 2.5m Nordic (NOT) telescope (La Palma, Tenerife) in the B passband and with the 2.2m Calar Alto telescope (CAFOS, R filter) yielded eclipse light curves with complete orbital phase coverage at high time resolution. A periodogram analysis of 12 primary minimum times distributed over the time span from October 2000 to March 2001 allowed to derive the following exact period and linear ephemeris: prim. min. = HJD 2451822.759782(22) + 0.09564665(39) ṡ E A total of 15 spectra taken with the 3.5m Calar Alto telescope (TWIN spectrograph) on March 11-12, 2001, were used to establish the radial velocity curve of the primary star (K1 = 85.8 km/s) , and to determine its basic atmospheric parameters (Teff = 29300 K, log g = 5.47). The B and R light curves were solved using our Wilson-Devinney based light curve analysis code MORO (Drechsel et al. 1995, A&A 294, 723). The best fit solution yielded exact system parameters consistent with the spectroscopic results. Detailed results will be published elsewhere (Drechsel et al. 2001, A&A, in preparation).

  13. SdH oscillations and pressure effect of the Weyl semimetal NbAs

    NASA Astrophysics Data System (ADS)

    Luo, Yongkang; Ghimire, N. J.; Wartenbe, M.; Choi, Hongchul; Neupane, M.; McDonald, R. D.; Bauer, E. D.; Zhu, Jianxin; Thompson, J. D.; Ronning, F.

    Via angular Shubnikov-de Hass (SdH) quantum oscillations measurements, we determine the Fermi surface topology of NbAs. The SdH oscillations consist of two frequencies, corresponding to two Fermi surface extrema: 20.8 T (α-pocket) and 15.6 T (β-pocket). The analysis shows that the β-pocket has a Berry phase of π and a small effective mass 0.033 m0, indicative of a nontrivial topology; whereas the α-pocket has a trivial Berry phase of 0 and a heavier effective mass 0.066 m0. Subtle changes can be seen in the ρxx(T) profiles with pressure up to 2.31 GPa. The Fermi surfaces undergo an anisotropic evolution under pressure, while the topological features of the two pockets remain unchanged. Specific heat measurements reveal a small Sommerfeld coefficient γ0 = 0.09(1) mJ/(molK2) and a large Debye temperature, ΘD = 450(9) K, confirming a ``hard'' crystalline lattice that is stable under pressure. We also studied the Kadowaki-Woods ratio of this low-carrier-density massless system, RKW = 3.2×104µ Ω cm mol2K2J-2. After accounting for the small carrier density in NbAs, this RKW indicates a suppressed transport scattering rate relative to other metals.

  14. SdH oscillations and pressure effect of the Weyl semimetal NbAs

    NASA Astrophysics Data System (ADS)

    Luo, Yongkang; Ghimire, N. J.; Wartenbe, M.; Choi, Hongchul; Neupane, M.; McDonald, R. D.; Bauer, E. D.; Zhu, Jianxin; Thompson, J. D.; Ronning, F.

    Via angular Shubnikov-de Hass (SdH) quantum oscillations measurements, we determine the Fermi surface topology of NbAs. The SdH oscillations consist of two frequencies: 20.8 T (α-pocket) and 15.6 T (β-pocket). The analysis shows that the β-pocket has a Berry phase of π and a small effective mass 0.033 m0, indicative of a nontrivial topology; whereas the α-pocket has a trivial Berry phase of 0 and a heavier effective mass 0.066 m0. Subtle changes can be seen in the ρxx(T) profiles with pressure up to 2.31 GPa. The Fermi surfaces undergo an anisotropic evolution under pressure, while the topological features of the two pockets remain unchanged. Specific heat measurements reveal a small Sommerfeld coefficient γ0 = 0.09(1) mJ/(molK2) and a large Debye temperature, ΘD = 450(9) K, confirming a ``hard'' crystalline lattice. The Kadowaki-Woods ratio and a suppressed transport scattering rate are also studied.

  15. An automated framework for 3D serous pigment epithelium detachment segmentation in SD-OCT images

    PubMed Central

    Sun, Zhuli; Chen, Haoyu; Shi, Fei; Wang, Lirong; Zhu, Weifang; Xiang, Dehui; Yan, Chenglin; Li, Liang; Chen, Xinjian

    2016-01-01

    Pigment epithelium detachment (PED) is an important clinical manifestation of multiple chorioretinal diseases, which can cause loss of central vision. In this paper, an automated framework is proposed to segment serous PED in SD-OCT images. The proposed framework consists of four main steps: first, a multi-scale graph search method is applied to segment abnormal retinal layers; second, an effective AdaBoost method is applied to refine the initial segmented regions based on 62 extracted features; third, a shape-constrained graph cut method is applied to segment serous PED, in which the foreground and background seeds are obtained automatically; finally, an adaptive structure elements based morphology method is applied to remove false positive segmented regions. The proposed framework was tested on 25 SD-OCT volumes from 25 patients diagnosed with serous PED. The average true positive volume fraction (TPVF), false positive volume fraction (FPVF), dice similarity coefficient (DSC) and positive predictive value (PPV) are 90.08%, 0.22%, 91.20% and 92.62%, respectively. The proposed framework can provide clinicians with accurate quantitative information, including shape, size and position of the PED region, which can assist clinical diagnosis and treatment. PMID:26899236

  16. The role of glutathione detoxification pathway in MCLR-induced hepatotoxicity in SD rats.

    PubMed

    Li, Shangchun; Chen, Jun; Xie, Ping; Guo, Xiaochun; Fan, Huihui; Yu, Dezhao; Zeng, Cheng; Chen, Liang

    2015-12-01

    In the present study, we investigated the role of glutathione (GSH) and its related enzymes in Sprague Dawley (SD) rats subjected to microcystin-leucine-arginine (MCLR)-induced hepatotoxicity. SD rats were intraperitoneally (i.p.) injected with MCLR after pretreating with or without buthionine-(S,R)-sulfoximine (BSO), an inhibitor of GSH synthesis. The depletion of GSH with BSO enhanced MCLR-induced oxidative stress, resulting in more severe liver damage and higher MCLR accumulation. Similarly, the contents of malondialdehyde (MDA), total GSH (T-GSH), oxidized GSH (GSSG) and GSH were significantly enhanced in BSO pretreated rats following MCLR treatment. The study showed that the transcription of GSH-related enzymes such as glutathione-S-transferase (GST), γ-glutamylcysteine synthetase (γ-GCS), glutathione reductase (GR) varied in different ways (expect for glutathione peroxidase (GPx), whose gene expression was induced in all treated groups) with or without BSO pretreatment before MCLR exposure, suggesting an adaptative response of GSH-related enzymes at transcription level to combat enhancement of oxidative stress induced by MCLR when pretreated with BSO. These data suggested the tissues with low GSH concentration are highly vulnerable to MCLR toxicity and GSH was critical for the detoxification in MCLR-induced hepatotoxicity in vivo. PMID:24964298

  17. Complex dynamics of an archetypal self-excited SD oscillator driven by moving belt friction

    NASA Astrophysics Data System (ADS)

    Zhi-Xin, Li; Qing-Jie, Cao; Léger, Alain

    2016-01-01

    We propose an archetypal self-excited system driven by moving belt friction, which is constructed with the smooth and discontinuous (SD) oscillator proposed by the Cao et al. and the classical moving belt. The moving belt friction is modeled as the Coulomb friction to formulate the mathematical model of the proposed self-excited SD oscillator. The equilibrium states of the unperturbed system are obtained to show the complex equilibrium bifurcations. Phase portraits are depicted to present the hyperbolic structure transition, the multiple stick regions, and the friction-induced asymmetry phenomena. The numerical simulations are carried out to demonstrate the friction-induced vibration of multiple stick-slip phenomena and the stick-slip chaos in the perturbed self-excited system. The results presented here provide an opportunity for us to get insight into the mechanism of the complex friction-induced nonlinear dynamics in mechanical engineering and geography. Project supported by the National Natural Science Foundation of China (Grant Nos. 11372082 and 11572096) and the National Basic Research Program of China (Grant No. 2015CB057405).

  18. FUV, UV, and Optical Observations of the He-sdO Star BD+39 3226

    NASA Astrophysics Data System (ADS)

    Chayer, Pierre; Green, E. M.; Fontaine, G.

    2014-01-01

    Based on observations carried out with the Far Ultraviolet Spectroscopic Explorer, the Space Telescope Imaging Spectrograph, the MMT Observatory, and the Keck telescope HIRES spectrograph, we present a spectral analysis of the He-sdO star BD+39 3226. By fitting the MMT spectrum we obtain a gravity that is 0.7 dex higher than the one reported in the literature. The new atmospheric parameters will have an impact on the measurement of the HI column density toward BD+39 3226, and by this very fact on the deuterium abundance. The high-resolution spectra show stellar absorption lines coming from C, N, O, Si, P, S, Fe, and Ni. The spectra also show lines from heavy elements such as Ge, As, and Sn. On the other hand, neither Zr nor Pb absorption lines are detected. The non-detection of lead in BD+39 3226 indicates that the star does not belong to the newly discovered group of lead-rich He-sdO stars. P.C. is supported by the Canadian Space Agency under a Public Works and Government Services of Canada contract.

  19. A framework for classification and segmentation of branch retinal artery occlusion in SD-OCT

    NASA Astrophysics Data System (ADS)

    Guo, Jingyun; Shi, Fei; Zhu, Weifang; Chen, Haoyu; Chen, Xinjian

    2016-03-01

    Branch retinal artery occlusion (BRAO) is an ocular emergency which could lead to blindness. Quantitative analysis of BRAO region in the retina is very needed to assessment of the severity of retinal ischemia. In this paper, a fully automatic framework was proposed to classify and segment BRAO based on 3D spectral-domain optical coherence tomography (SD-OCT) images. To the best of our knowledge, this is the first automatic 3D BRAO segmentation framework. First, a support vector machine (SVM) based classifier is designed to differentiate BRAO into acute phase and chronic phase, and the two types are segmented separately. To segment BRAO in chronic phase, a threshold-based method is proposed based on the thickness of inner retina. While for segmenting BRAO in acute phase, a two-step segmentation is performed, which includes the bayesian posterior probability based initialization and the graph-search-graph-cut based segmentation. The proposed method was tested on SD-OCT images of 23 patients (12 of acute and 11 of chronic phase) using leave-one-out strategy. The overall classification accuracy of SVM classifier was 87.0%, and the TPVF and FPVF for acute phase were 91.1%, 5.5%; for chronic phase were 90.5%, 8.7%, respectively.

  20. Geology of the USW SD-9 drill hole, Yucca Mountain, Nevada

    SciTech Connect

    Engstrom, D.A.; Rautman, C.A.

    1996-10-01

    Drill hole USW SD-9 is one of several holes drilled under Site Characterization Plan Study as part of the characterization program at Yucca Mountain, Nevada, which has been proposed as the potential location of a repository for high-level nuclear waste. The SD-9 drill hole is located in the northern part of the potential repository area. Quantitative and semiquantitative data are included in this report for cover recovery, rock-quality designation (RQD), lithophysal cavity abundance, and fracturing. These data are spatially variable, both within and among the major formational-level stratigraphic units. Nonwelded intervals in general exhibit higher recoveries and more intact (higher) RQD values than welded intervals. The most intact, highest-RQD materials encountered within the Topopah Spring belong to the lower 33.3 ft of the middle nonlithophysal zone. This report includes quantitative data for the framework material properties of porosity, bulk and particle density, and saturated hydraulic conductivity. Graphical analysis of variations in these laboratory hydrologic properties indicates first-order control of material properties by the degree of welding and the presence of zeolite minerals. Many major lithostratigraphic contacts are not well expressed in the material-property profiles; contacts of material-property units are related more to changes in the intensity of welding. Approximate in-situ saturation data of samples preserved immediately upon recovery from the hole are included in the data tabulation.

  1. Innovative solid oxide fuel cells based on BaIn0.3Ti0.7O2.85 electrolyte and La2Mo2O9 amorphous reduced phase as anode material

    NASA Astrophysics Data System (ADS)

    Buvat, Gaëtan; Quarez, Eric; Joubert, Olivier

    2016-01-01

    This article presents elaboration of electrolyte-supported solid oxide fuel cells based on the oxide ion conductor BaIn0.3Ti0.7O2.85 (BIT07) as electrolyte, the amorphous reduced phase of La2Mo2O9 (La2Mo2O7-y) as anode which presents a mixed ionic and electronic conduction in low pO2 and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) as cathode. Electrode materials have been deposited by screen-printing on BIT07 substrate. In order to avoid chemical reactivity between BIT07 and La2Mo2O9, a thin layer of Ce0.9Gd0.1O1.95 (CGO) has been used. Electrochemical performance of the single cell has been characterized by I-V measurements and impedance spectroscopy. Encouraging performance of 40 mW cm-2 at 700 °C is obtained with a thick electrolyte layer. Finally, ageing test of the cell at 700 °C during 800 h has been done with a low rate of performance loss of 4.4 × 10-3% h-1. No degradation of the electrolyte material is reported and stability of the anode material after operating the fuel cell is discussed.

  2. Synthesis, characterization and crystal structure of a novel Strandberg-type polyoxoselenomolybdate Rb{sub 4}[Se{sub 2}Mo{sub 5}O{sub 21}]{center_dot}2H{sub 2}O

    SciTech Connect

    Nagazi, Ichraf; Haddad, Amor

    2012-02-15

    Graphical abstract: Crystal structure of Rb{sub 4}[Se{sub 2}Mo{sub 5}O{sub 21}]{center_dot}2H2O. Highlights: Black-Right-Pointing-Pointer Synthesis of the first Strandberg-type polyoxoselenomolybdate Rb{sub 4}[Se{sub 2}Mo{sub 5}O{sub 21}]{center_dot}2H{sub 2}O. Black-Right-Pointing-Pointer Characterization of the novel compound. Black-Right-Pointing-Pointer Chirality of the space group C2 of compound implies that it is expected to have nonlinear optical (NLO) properties -- Abstract: An inorganic compound formulated as Rb{sub 4}[Se{sub 2}Mo{sub 5}O{sub 21}]{center_dot}2H{sub 2}O (1) has been isolated by conventional solution method and structurally characterized by single-crystal X-ray diffraction methods, scanning electron microscopy (SEM), powder XRD, IR, UV-vis spectra, and cyclic voltammetry measurements. This compound crystallizes in the monoclinic system, space group C2 with unit a = 19.701 (3) Angstrom-Sign , b = 10.296 (2) Angstrom-Sign , c = 12.134 (4) Angstrom-Sign , {beta} = 106.96 (2) Degree-Sign and Z = 4. The crystal structure of (1) is built up from a Strandberg clusters connected through hydrogen-bonding interactions into a three-dimensional supramolecular network.

  3. Global shear velocity heterogeneities in the D″ layer: Inversion from Sd-SKS differential travel times

    NASA Astrophysics Data System (ADS)

    Kuo, Ban-Yuan; Wu, Kuan-Yi

    1997-06-01

    A global map of shear velocity in the D″ layer results from the inversion of 340 differential travel times of diffracted S(SH) minus SKS(SV) (Sd-SKS), from long-period records of global seismic networks. The two-phase design reduces contamination from upper mantle heterogeneities and errors in location and origin time of the events. Additional corrections are made for (1) azimuthal anisotropy at stations where shear wave splitting parameters are available and for (2) travel time perturbations due to lower mantle asphericity, although both effects are minor compared with the observed residuals with respect to the preliminary reference Earth model (PREM) [Dziewonski and Anderson, 1981]. The corrected residuals, ranging from -16 to 18 s, are attributed to anomalies in D″ sampled by both phases. Taking these residuals as data and assuming a constant, 250-km-thick D″ layer, we invert for a lateral velocity variation model of D″ using spherical harmonics. In parameterizing D″ velocities, a high degree expansion (L=14) avoids aliasing, but only the reliably determined, low degree components (LI

  4. Identification of the orphan GPCR, P2Y(10) receptor as the sphingosine-1-phosphate and lysophosphatidic acid receptor.

    PubMed

    Murakami, Masanori; Shiraishi, Akira; Tabata, Kenichi; Fujita, Norihisa

    2008-07-11

    Phylogenetic analysis of transmembrane regions of GPCRs using PHYLIP indicated that the orphan receptor P2Y(10) receptor was classified into the cluster consisting nucleotide and lipid receptors. Based on the results, we studied the abilities of nucleotides and lipids to activate the P2Y(10) receptors. As a result, sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) evoked intracellular Ca(2+) increases in the CHO cells stably expressing the P2Y(10) fused with a G(16alpha) protein. These Ca(2+) responses were inhibited by S1P receptor and LPA receptor antagonists. The introduction of siRNA designed for P2Y(10) receptor into the P2Y(10)-CHO cells effectively blocked both S1P- and LPA-induced Ca(2+) increases. RT-PCR analysis showed that the mouse P2Y(10) was expressed in reproductive organs, brain, lung and skeletal muscle, suggesting the receptor plays physiological roles throughout the whole body. In conclusion, the P2Y(10) receptor is the first receptor identified as a dual lysophospholipid receptor. PMID:18466763

  5. Effect of Laves Phase on High-Temperature Deformation and Microstructure Evolution in an 18Cr-2Mo-0.5Nb Ferritic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Ikeda, Ken-ichi; Yamoah, Nana Kwame Gyan; Reynolds, William T.; Hamada, Jun-ichi; Murayama, Mitsuhiro

    2015-08-01

    Niobium-containing ferritic stainless steels are finding new applications in automotive exhaust components because of their oxidation resistance, thermal fatigue resistance, and high-temperature strength. The mechanical behavior of Nb-containing ferritic steels at service temperatures of 973 K (700 °C) and higher results from the convolution of dynamic microstructural changes including precipitation, precipitate coarsening, strain hardening, recovery, and recrystallization. The relative contributions of these competing processes have yet to be clarified. In this study, the high-temperature flow strength of an 18Cr-2Mo-0.5Nb ferritic stainless steel (SUS 444) was correlated with microstructure under different strain and initial precipitate distributions to clarify the relative role of the strengthening and softening processes. High-temperature tensile tests at 1023 K (750 °C) of un-aged (initial microstructure is precipitate-free) and pre-aged (initial microstructure contains precipitates) samples were carried out and transmission electron microscopy was used to assess dislocation distributions and precipitate morphology. The difference in the stress-strain curves between un-aged and pre-aged samples was drastic; the yield strength of the un-aged sample was twice that of the pre-aged sample, and the un-aged sample exhibits a noticeable yield drop. Transmission electron microscopy revealed a Laves phase nucleated and grew during the high-temperature tensile test in the un-aged sample and the majority of the precipitates in the pre-aged sample were the same Laves phase. Furthermore, a strain effect on precipitate growth was recognized in un-aged and pre-aged conditions by comparing grip (no strain) and gage (strained) sections of tensile samples. The dominant strengthening contribution in un-aged samples is initially the precipitate shearing mechanism and it changes to Orowan strengthening beyond the ultimate tensile strength, whereas the dominant contribution in

  6. Observation of Switchable Photoresponse of a Monolayer WSe2-MoS2 Lateral Heterostructure via Photocurrent Spectral Atomic Force Microscopic Imaging.

    PubMed

    Son, Youngwoo; Li, Ming-Yang; Cheng, Chia-Chin; Wei, Kung-Hwa; Liu, Pingwei; Wang, Qing Hua; Li, Lain-Jong; Strano, Michael S

    2016-06-01

    In the pursuit of two-dimensional (2D) materials beyond graphene, enormous advances have been made in exploring the exciting and useful properties of transition metal dichalcogenides (TMDCs), such as a permanent band gap in the visible range and the transition from indirect to direct band gap due to 2D quantum confinement, and their potential for a wide range of device applications. In particular, recent success in the synthesis of seamless monolayer lateral heterostructures of different TMDCs via chemical vapor deposition methods has provided an effective solution to producing an in-plane p-n junction, which is a critical component in electronic and optoelectronic device applications. However, spatial variation of the electronic and optoelectonic properties of the synthesized heterojunction crystals throughout the homogeneous as well as the lateral junction region and the charge carrier transport behavior at their nanoscale junctions with metals remain unaddressed. In this work, we use photocurrent spectral atomic force microscopy to image the current and photocurrent generated between a biased PtIr tip and a monolayer WSe2-MoS2 lateral heterostructure. Current measurements in the dark in both forward and reverse bias reveal an opposite characteristic diode behavior for WSe2 and MoS2, owing to the formation of a Schottky barrier of dissimilar properties. Notably, by changing the polarity and magnitude of the tip voltage applied, pixels that show the photoresponse of the heterostructure are observed to be selectively switched on and off, allowing for the realization of a hyper-resolution array of the switchable photodiode pixels. This experimental approach has significant implications toward the development of novel optoelectronic technologies for regioselective photodetection and imaging at nanoscale resolutions. Comparative 2D Fourier analysis of physical height and current images shows high spatial frequency variations in substrate/MoS2 (or WSe2) contact that

  7. The modulated structure and frequency upconversion properties of CaLa2(MoO4)4:Ho(3+)/Yb(3+) phosphors prepared by microwave synthesis.

    PubMed

    Lim, Chang Sung; Aleksandrovsky, Aleksandr; Molokeev, Maxim; Oreshonkov, Aleksandr; Atuchin, Victor

    2015-07-15

    CaLa2-x(MoO4)4:Ho(3+)/Yb(3+) phosphors with the doping concentrations of Ho(3+) and Yb(3+) (x = Ho(3+) + Yb(3+), Ho(3+) = 0.05; Yb(3+) = 0.35, 0.40, 0.45 and 0.50) have been successfully synthesized by the microwave sol-gel method. The modulated and averaged crystal structures of CaLa2-x(MoO4)4:Ho(3+)/Yb(3+) molybdates have been found by the Rietveld method, and the upconversion photoluminescence properties have been investigated. The synthesized particles, being formed after the heat-treatment at 900 °C for 16 h, showed a highly crystallized state. Under the excitation at 980 nm, CaLa2-x(MoO4)4:Ho(3+)/Yb(3+) particles exhibited strong 545 and 655 nm emission bands in the green and red regions. When the Yb(3+) : Ho(3+) ratios are 9 : 1 and 10 : 1, the UC intensity of CaLa1.5(MoO4)4:Yb0.45/Ho0.05 and CaLa1.45(MoO4)4:Yb0.50/Ho0.05 particles is the highest for different bands. The CIE coordinates calculated for CaLa2-x(MoO4)4:Ho(3+)/Yb(3+) phosphors are related to the yellow color field. The Raman spectrum of undoped CaLa2(MoO4)4 has revealed about 13 narrow lines. The strongest band observed at 906 cm(-1) was assigned to the ν1 symmetric stretching vibration of MoO4 tetrahedra. The spectra of the samples doped with Ho and Yb, as obtained under the 514.5 nm excitation, were dominated by Ho(3+) luminescence over the wavenumber range of >700 cm(-1) preventing the recording of the Raman spectra. PMID:26138938

  8. LPS potentiates nucleotide-induced inflammatory gene expression in macrophages via the upregulation of P2Y2 receptor.

    PubMed

    Eun, So Young; Seo, Jihye; Park, Sang Won; Lee, Jae Heun; Chang, Ki Churl; Kim, Hye Jung

    2014-02-01

    Sepsis is a severe systemic inflammatory response that is associated with high morbidity and mortality. A previous study using an animal model of sepsis showed that survival was significantly lower in WT mice than in P2Y(2) receptor (P2Y(2)R)-deficient mice, suggesting that P2Y(2)R plays a role in septic death. We therefore investigated the role of P2Y(2)R in the inflammatory responses of RAW264.7 murine macrophages to LPS. LPS time-dependently upregulated P2Y(2)R mRNA levels, with a prominent increase observed at 4 h. In addition, LPS increased ATP release in a time dependent manner (5-120 min post LPS treatment). Accordingly, we pretreated cells with LPS for 4 h to induce P2Y(2)R expression and then stimulated the cells with UTP or ATP for 16 h. Interestingly, ATP- or UTP-dependent P2Y(2)R activation in LPS-pretreated cells resulted in dramatically enhanced HMGB1 secretion, COX-2 and iNOS expression, and furthermore PGE2 and NO production compared to LPS treatment alone (4 h) or ATP or UTP treatment alone (16 h), an effect that was inhibited by P2Y(2)R silencing. In addition, these increases in HMGB1 secretion, COX-2 and iNOS expression and PGE(2) and NO production commonly involved the JNK, PKC and PDK pathways. Taken together, these data demonstrate that LPS-dependent upregulation of P2Y(2)R plays a critical role in facilitating the inflammatory responses induced by LPS. PMID:24316256

  9. P2Y12 antagonists in non-ST-segment elevation acute coronary syndromes: latest evidence and optimal use

    PubMed Central

    DiNicolantonio, James J.

    2015-01-01

    Dual antiplatelet therapy (DAPT), which includes the combination of aspirin and a P2Y12 platelet receptor inhibitor, is a well-established antiplatelet regimen in the treatment of patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Three P2Y12 inhibitor options (clopidogrel, prasugrel and ticagrelor) are currently available, all having different efficacy and safety profiles along with contrasting contraindications, special warnings and precautions for use. This review compares and contrasts the unique P2Y12 antagonists in the NSTE-ACS setting, covering the latest evidence and their optimal use. PMID:26137210

  10. Important operational parameters of membrane bioreactor-sludge disintegration (MBR-SD) system for zero excess sludge production.

    PubMed

    Yoon, Seong-Hoon

    2003-04-01

    In order to prevent excess sludge production during wastewater treatment, a membrane bioreactor-sludge disintegration (MBR-SD) system has been introduced, where the disintegrated sludge is recycled to the bioreactor as a feed solution. In this study, a mathematical model was developed by incorporating a sludge disintegration term into the conventional activated sludge model and the relationships among the operational parameters were investigated. A new definition of F/M ratio for the MBR-SD system was suggested to evaluate the actual organic loading rate. The actual F/M ratio was expected to be much higher than the apparent F/M ratio in MBR-SD. The kinetic parameters concerning the biodegradability of organics hardly affect the system performance. Instead, sludge solubilization ratio (alpha) in the SD process and particulate hydrolysis rate constant (k(h)) in biological reaction determine the sludge disintegration number (SDN), which is related with the overall economics of the MBR-SD system. Under reasonable alpha and k(h) values, SDN would range between 3 and 5 which means the amount of sludge required to be disintegrated would be 3-5 times higher for preventing a particular amount of sludge production. Finally, normalized sludge disintegration rate (q/V) which is needed to maintain a certain level of MLSS in the MBR-SD system was calculated as a function of F/V ratio. PMID:12697235

  11. Absolute density measurement of SD radicals in a supersonic jet at the quantum-noise-limit.

    PubMed

    Mizouri, Arin; Deng, L Z; Eardley, Jack S; Nahler, N Hendrik; Wrede, Eckart; Carty, David

    2013-12-01

    The absolute density of SD radicals in a supersonic jet has been measured down to (1.1 ± 0.1) × 10(5) cm(-3) in a modestly specified apparatus that uses a cross-correlated combination of cavity ring-down and laser-induced fluorescence detection. Such a density corresponds to 215 ± 21 molecules in the probe volume at any given time. The minimum detectable absorption coefficient was quantum-noise-limited and measured to be (7.9 ± 0.6) × 10(-11) cm(-1), in 200 s of acquisition time, corresponding to a noise-equivalent absorption sensitivity for the apparatus of (1.6 ± 0.1) × 10(-9) cm(-1) Hz(-1/2). PMID:24145480

  12. Microsporum fulvum IBRL SD3: as novel isolate for chicken feathers degradation.

    PubMed

    Darah, I; Nur-Diyana, A; Nurul-Husna, S; Jain, K; Lim, Sheh-Hong

    2013-12-01

    Keratinous wastes have increasingly become a problem and accumulate in the environment mainly in the form of feathers, generated mainly from a large number of poultry industries. As keratins are very difficult to degrade by general proteases, they pose a major environmental problem. Therefore, microorganisms which would effectively degrade keratins are needed for recycling such wastes. A geophilic dermatophyte, Microsporum fulvum IBRL SD3 which was isolated from a soil sample collected from a chicken feather dumping site using a baiting technique, was capable to produce keratinase significantly. The crude keratinase was able to degrade whole chicken feathers effectively. The end product of the degradation was protein that contained essential amino acids and may have potential application in animal feed production. Thus, M. fulvum could be a novel organism to produce keratinase for chicken feathers degradation. PMID:24013862

  13. Secondary metabolites from Penicillium pinophilum SD-272, a marine sediment-derived fungus.

    PubMed

    Wang, Ming-Hui; Li, Xiao-Ming; Li, Chun-Shun; Ji, Nai-Yun; Wang, Bin-Gui

    2013-06-01

    Two new secondary metabolites, namely, pinodiketopiperazine A (1) and 6,7-dihydroxy-3-methoxy-3-methylphthalide (2), along with alternariol 2,4-dimethyl ether (3) and L-5-oxoproline methyl ester (4), which were isolated from a natural source for the first time but have been previously synthesized, were characterized from the marine sediment-derived fungus Penicillium pinophilum SD-272. In addition, six known metabolites (5-10) were also identified. Their structures were elucidated by analysis of the NMR and mass spectroscopic data. The absolute configuration of compound 1 was determined by experimental and calculated ECD spectra. Compound 2 displayed potent brine shrimp (Artemia salina) lethality with LD₅₀ 11.2 μM. PMID:23792827

  14. Electrical Characterization of the RCA CDP1822SD Random Access Memory, Volume 1, Appendix a

    NASA Technical Reports Server (NTRS)

    Klute, A.

    1979-01-01

    Electrical characteristization tests were performed on 35 RCA CDP1822SD, 256-by-4-bit, CMOS, random access memories. The tests included three functional tests, AC and DC parametric tests, a series of schmoo plots, rise/fall time screening, and a data retention test. All tests were performed on an automated IC test system with temperatures controlled by a thermal airstream unit. All the functional tests, the data retention test, and the AC and DC parametric tests were performed at ambient temperatures of 25 C, -20 C, -55 C, 85 C, and 125 C. The schmoo plots were performed at ambient temperatures of 25 C, -55 C, and 125 C. The data retention test was performed at 25 C. Five devices failed one or more functional tests and four of these devices failed to meet the expected limits of a number of AC parametric tests. Some of the schmoo plots indicated a small degree of interaction between parameters.

  15. Isospin Symmetry Along The N=Z Line In The sd Shell

    SciTech Connect

    Della Vedova, F.; Lenzi, S. M.; Farnea, E.; Nespolo, M.; Bazzacco, D.; Brandolini, F.; Lunardi, S.; Menegazzo, R.; Rossi Alvarez, C.; Ur, C.A.; Ionescu-Bujor, M.; Bucurescu, D.; Iordachescu, A.; Marginean, N.; De Angelis, G.; Axiotis, M.; Napoli, D. R.; Bizzeti-Sona, A.; Bizzeti, P.G.

    2005-04-05

    Excited states have been studied in sd-shell nuclei following the 16O (70 MeV) + 24Mg (400 {mu}g/cm2) fusion-evaporation reaction. The GASP spectrometer in conjunction with the charged-particle detector ISIS and the Neutron ring allowed the detection of the {gamma}-rays in coincidence with evaporated light particles. New data on the mirror pairs A=31 and A=35 have been obtained. In particular, the comparison between the level schemes of 35Ar and 35Cl has confirmed the importance of the electromagnetic spin-orbit term, which explains the large Mirror Energy Difference values. Evidence of isospin mixing can be deduced from the E1 transitions.

  16. Support vector machine based IS/OS disruption detection from SD-OCT images

    NASA Astrophysics Data System (ADS)

    Wang, Liyun; Zhu, Weifang; Liao, Jianping; Xiang, Dehui; Jin, Chao; Chen, Haoyu; Chen, Xinjian

    2014-03-01

    In this paper, we sought to find a method to detect the Inner Segment /Outer Segment (IS/OS)disruption region automatically. A novel support vector machine (SVM) based method was proposed for IS/OS disruption detection. The method includes two parts: training and testing. During the training phase, 7 features from the region around the fovea are calculated. Support vector machine (SVM) is utilized as the classification method. In the testing phase, the training model derived is utilized to classify the disruption and non-disruption region of the IS/OS, and calculate the accuracy separately. The proposed method was tested on 9 patients' SD-OCT images using leave-one-out strategy. The preliminary results demonstrated the feasibility and efficiency of the proposed method.

  17. Source identification in acoustics and structural mechanics using Sierra/SD.

    SciTech Connect

    Walsh, Timothy Francis; Aquino, Wilkins; Ross, Michael

    2013-03-01

    In this report we derive both time and frequency-domain methods for inverse identification of sources in elastodynamics and acoustics. The inverse/design problem is cast in a PDE-constrained optimization framework with efficient computation of gradients using the adjoint method. The implementation of source inversion in Sierra/SD is described, and results from both time and frequency domain source inversion are compared to actual experimental data for a weapon store used in captive carry on a military aircraft. The inverse methodology is advantageous in that it provides a method for creating ground based acoustic and vibration tests that can reduce the actual number of flight tests, and thus, saving costs and time for the program.

  18. Toxicity of Methylcyclohexane and Its Effect on the Reproductive System in SD Rats

    PubMed Central

    Kang, Min-Gu; Kim, Tae-Gyun; Kang, Chung-Won

    2011-01-01

    Objectives There is limited data regarding the toxicity of methylcyclohexane, despite its wide use in rubber adhesives, paint diluents, and cleansing agents. This study aimed to verify the toxicity and influence on the reproductive system of methylcyclohexane after its repeated injection in Sprague Dawley (SD) rats. Methods Methylcyclohexane was injected subcutaneously into male and female SD rats once a day, five times a week, for 13 weeks at different doses (0, 10, 100, and 1,000 mg/kg/day) for each group. The toxicity of testing material was verified by observing the change in body and organ weight, hematological change, pathological findings, and effect on the reproductive system at each different concentration. Results In the 1,000 mg/kg/day group, there were cases of animal deaths. In animals that survived, hematological changes, including a decrease in the red blood cell count, were observed. A considerable weight gain or loss and pathological abnormalities in the liver, kidney, and other organs were found. However, the 10 and 100 mg/kg/day groups did not cause deaths or other specific abnormalities. In terms of reproductive toxicity, there were changes in hormone levels, including a significant decrease in hormones such as estradiol and progesterone (p < 0.001) in male animals. Menstrual cycle change for female animals did not show concentration dependency. Conclusion When injected repeatedly for 13 weeks, methylcyclohexane proved to be toxic for the liver, heart, and kidney at a high dose. The absolute toxic dose was 1,000 mg/kg/day, while the no observed adverse effect level was less than 100 mg/kg/day. The substance exerted little influence on the reproductive system. PMID:22953213

  19. SAMI3/SD-WACCM-X simulations of ionospheric variability during northern winter 2009

    NASA Astrophysics Data System (ADS)

    McDonald, S. E.; Sassi, F.; Mannucci, A. J.

    2015-09-01

    We have performed simulations using the Naval Research Laboratory's physics-based model of the ionosphere, Sami3 is A Model of the Ionosphere (SAMI3), to illustrate how neutral wind dynamics is responsible for day-to-day variability of the ionosphere. We have used neutral winds specified from the extended version of the specified dynamics Whole Atmosphere Community Climate Model (SD-WACCM-X), in which meteorology below 92 km is constrained by atmospheric specifications from an operational weather forecast model and reanalysis. To assess the realism of the simulations against observations, we have carried out a case study during January-February 2009, a dynamically disturbed time characterized by a sudden stratospheric warming (SSW) commencing 24 January 2009. Model results are compared with total electron content (TEC) from Jet Propulsion Laboratory global ionospheric maps. We show that SAMI3/SD-WACCM-X captures longitudinal variability in the equatorial ionization anomaly associated with nonmigrating tides, with strongest contributions coming from the diurnal eastward wave number 2 (DE2) and DE3. Both migrating and nonmigrating tides contribute to significant day-to-day variability, with TEC varying up to 16%. Our simulation during the SSW period reveals that at the Jicamarca longitude (285°E) on 27 January 2009 nonmigrating tides contribute to an enhancement of the electron density in the morning followed by a decrease in the afternoon. An enhancement of the semidiurnal eastward wave number 2 (SE2) and SE3 nonmigrating tides, likely associated with the appearance of the SSW, suggests that these tides increase the longitudinal variability of the SSW impact on the ionosphere. The conclusion is that realistic meteorology propagating upward from the lower atmosphere influences the dynamo region and reproduces aspects of the observed variability in the ionosphere.

  20. The study of the Oxytropis kansuensis-induced apoptotic pathway in the cerebrum of SD rats

    PubMed Central

    2013-01-01

    Background Locoweeds cause significant livestock poisoning and economic loss all over the world. Animals can develop locoism, a chronic neurological disease, after grazing on locoweeds. Oxytropis kansuensis is a variety of locoweed that contains swainsonine as its main toxic ingredient. The purpose of this study was to investigate the apoptotic pathway induced in the cerebrum by swainsonine. Results Twenty-four Sprague-Dawley rats were randomly divided into four groups (experimental groups I, II, III and a control group) and 6 SD rats of each group were feed in 3 cages separately. Rats were penned as groups and fed with feeds containing 15% (SW content 0.03‰), 30% (SW content 0.06‰), or 45% (SW content 0.09‰) O. kansuensis for experimental groups I, II, and III, respectively, or complete feed in the case of the control group. One hundred and nineteen days after poisoning, and all rats showed neurological disorders at different degrees, which were considered to be successful established a chronic poisoning model of O. kansuensis. rats were sacrificed and the expression of Fas, FasL, Bcl-2, Bax as well as cleaved caspase-3, -8 and -9 proteins in brain tissues were detected by Western blot. The results showed that SW treatment up-regulated Fas and Fas ligand (FasL) (P < 0.05), and that there was an increase in Bax and a decrease in Bcl-2 protein (P < 0.01). Moreover, SW treatment significantly increases the activation of caspase-3, 8 and -9, the key effectors in apoptosis pathway (P < 0.01). Conclusion Our data suggest that SW induces apoptosis in cells of the brain through death receptor and mitochondria-mediated, caspase-dependent apoptotic pathways in the brain tissue of SD rats. PMID:24148892

  1. Lactogenic Activity of an Enzymatic Hydrolysate from Octopus vulgaris and Carica papaya in SD Rats.

    PubMed

    Cai, Bingna; Chen, Hua; Sun, Han; Sun, Huili; Wan, Peng; Chen, Deke; Pan, Jianyu

    2015-11-01

    The traditional Chinese medicine theory believes that octopus papaya soup can stimulate milk production in lactating women. The objective of this study was to determine whether dietary supplementation with an enzymatic hydrolysate of Octopus vulgaris and Carica papaya (EHOC) could increase milk production and nutritional indexes in Sprague Dawley (SD) rats. Female SD rats (n = 24) were fed a control diet (n = 8), EHOC-supplemented diet, or a positive control diet (Shengruzhi) from day 10 of pregnancy to day 10 of lactation. Maternal serum, mammary gland (day 10 of lactation), milk, and pup weight (daily) were collected for analysis. Results showed that the EHOC diet obviously elevated daily milk yield and pup weight compared to the control group (P < .05). The EHOC diet was found to increase the concentration of prolactin (PRL), progesterone (P), estradiol (E2), and growth hormone (GH) significantly in the circulation and mammary gland. Mammary glands of EHOC-treated dams showed clear lobuloalveolar development and proliferation of myoepithelial cells, but no striking variations were observed among the groups. Furthermore, the nutrition content and immune globulin concentration in the milk of EHOC-supplemented dams were higher than those of the control group, especially the cholesterol, glucose, and IgG were higher by 44.98% (P < .001), 42.76% (P < .01), and 42.23% (P < .01), respectively. In conclusion, this article demonstrates that EHOC administration has beneficial effects on milk production in the dams and on performance of the dam and pup. These results indicate that EHOC could be explored as a potentially lactogenic nutriment for lactating women. PMID:26270883

  2. Local Variability of Macular Thickness Measurements With SD-OCT and Influencing Factors

    PubMed Central

    Miraftabi, Arezoo; Amini, Navid; Gornbein, Jeff; Henry, Sharon; Romero, Pablo; Coleman, Anne L.; Caprioli, Joseph; Nouri-Mahdavi, Kouros

    2016-01-01

    Purpose To compare the intrasession variability of spectral-domain optical coherence tomography (SD-OCT)-derived local macular thickness measures and explore influencing factors. Methods One hundred two glaucomatous eyes (102 patients) and 21 healthy eyes (21 subjects) with three good quality macular images during the same session were enrolled. Thickness measurements were calculated for 3° superpixels for the inner plexiform (IPL), ganglion cell (GCL), or retinal nerve fiber layers (mRNFL), GC/IPL, ganglion cell complex, and full macular thickness. Spatial distribution and magnitude of measurement errors (ME; differences between the 3 individual superpixel values and their mean) and association between MEs and thickness, age, axial length, and image quality were explored. Results MEs had a normal distribution with mostly random noise along with a small fraction of outliers (1.2%–6.6%; highest variability in mRNFL and on the nasal border) based on M-estimation. Boundaries of 95% prediction intervals for variability reached a maximum of 3 μm for all layers and diagnostic groups after exclusion of outliers. Correlation between proportion of outliers and thickness measures varied among various parameters. Age, axial length, or image quality did not influence MEs (P > 0.05 for both groups). Conclusions Local variability of macular SD-OCT measurements is low and uniform across the macula. The relationship between superpixel thickness and outlier proportion varied as a function of the parameter of interest. Translational Relevance Given the low and uniform variability within and across eyes, definition of an individualized ‘variability space' seems unnecessary. The variability measurements from this study could be used for designing algorithms for detection of glaucoma progression. PMID:27486555

  3. Enhanced 77 K vortex-pinning in Y Ba2Cu3O7-x films with Ba2Y TaO6 and mixed Ba2Y TaO6 + Ba2Y NbO6 nano-columnar inclusions with irreversibility field to 11 T

    NASA Astrophysics Data System (ADS)

    Rizzo, F.; Augieri, A.; Angrisani Armenio, A.; Galluzzi, V.; Mancini, A.; Pinto, V.; Rufoloni, A.; Vannozzi, A.; Bianchetti, M.; Kursumovic, A.; MacManus-Driscoll, J. L.; Meledin, A.; Van Tendeloo, G.; Celentano, G.

    2016-06-01

    Pulsed laser deposited thin Y Ba2Cu3O7-x (YBCO) films with pinning additions of 5 at. % Ba2Y TaO6 (BYTO) were compared to films with 2.5 at. % Ba2Y TaO6 + 2.5 at. % Ba2Y NbO6 (BYNTO) additions. Excellent magnetic flux-pinning at 77 K was obtained with remarkably high irreversibility fields greater than 10 T (YBCO-BYTO) and 11 T (YBCO-BYNTO), representing the highest ever achieved values in YBCO films.

  4. A hot oxidant, 3-NO2Y122 radical, unmasks conformational gating in ribonucleotide reductase

    PubMed Central

    Yokoyama, Kenichi; Uhlin, Ulla; Stubbe, JoAnne

    2010-01-01

    Escherichia coli ribonucleotide reductase is an α2β2 complex that catalyzes the conversion of nucleotides to deoxynucleotides and requires a diferric-tyrosyl radical (Y•) cofactor to initiate catalysis. The initiation process requires long range proton-coupled electron transfer (PCET) over 35 Å between the two subunits by a specific pathway (Y122• → W48 → Y356 within β to Y731 → Y730 → C439 within α). The rate-limiting step in nucleotide reduction is the conformational gating of the PCET process, which masks the chemistry of radical propagation. 3-Nitrotyrosine (NO2Y) has recently been incorporated site-specifically in place of Y122 in β2. The protein as isolated contained a diferric cluster, but no nitrotyrosyl radical (NO2Y•) and was inactive. In the present paper we show that incubation of apo-Y122NO2Y-β2 with Fe2+ and O2 generates a diferric-NO2Y• that has a half-life of 40 s at 25 °C. Sequential mixing experiments, in which the cofactor is assembled to 1.2 NO2Y•/β2 and then mixed with α2, CDP, and ATP, have been analyzed by stopped flow spectroscopy, rapid freeze quench EPR spectroscopy and rapid chemical quench methods. These studies have for the first time unmasked the conformational gating. They reveal that the NO2Y• is reduced to the nitrotyrosinate with biphasic kinetics (283 and 67 s-1), that dCDP is produced at 107 s-1, and that a new Y• is produced at 97 s-1. Studies with pathway mutants suggest that the new Y• is predominantly located at 356 in β2. In conjunction with the crystal structure of Y122NO2Y-β2, a mechanism for PCET uncoupling in NO2Y•-RNR is proposed. PMID:20929229

  5. Giant increase in critical current density of KxFe2-ySe₂ single crystals

    DOE PAGESBeta

    Lei, Hechang; Petrovic, C.

    2011-12-28

    The critical current density Jabc of KxFe2-ySe₂ single crystals can be enhanced by more than one order of magnitude, up to ~2.1×10⁴ A/cm² by the post annealing and quenching technique. A scaling analysis reveals the universal behavior of the normalized pinning force as a function of the reduced field for all temperatures, indicating the presence of a single vortex pinning mechanism. The main pinning sources are three-dimensional (3D) point-like normal cores. The dominant vortex interaction with pinning centers is via spatial variations in critical temperature Tc (“δTc pinning”).

  6. Reviewing the controversy surrounding pre-treatment with P2Y12 inhibitors in acute coronary syndrome patients.

    PubMed

    Capodanno, Davide; Angiolillo, Dominick J

    2016-07-01

    Pretreatment with oral P2Y12 inhibitors occurs each time clopidogrel, prasugrel, ticagrelor are given to patients with suspected coronary artery disease before definition of the coronary anatomy. In acute coronary syndromes, the practice of administering oral P2Y12 inhibitors upstream has been the object of significant controversy in recent years, following the publication of two trials of pretreatment in non-ST-segment elevation acute coronary syndromes and ST-segment elevation myocardial infarction, respectively. The introduction in the market of cangrelor - the first intravenous P2Y12 inhibitor - represents a new opportunity but also a new challenge for clinicians. This article reviews current recommendations and supporting evidence surrounding pretreatment with oral and intravenous P2Y12 inhibitors in patients with acute coronary syndromes. PMID:26953527

  7. P2Y2 receptor up-regulation induced by guanosine or UTP in rat brain cultured astrocytes.

    PubMed

    Ballerini, P; Di Iorio, P; Caciagli, F; Rathbone, M P; Jiang, S; Nargi, E; Buccella, S; Giuliani, P; D'Alimonte, I; Fischione, G; Masciulli, A; Romano, S; Ciccarelli, R

    2006-01-01

    Among P2 metabotropic ATP receptors, P2Y2 subtype seems to be peculiar as its upregulation triggers important biological events in different cells types. In non-stimulated cells including astrocytes, P2Y2 receptors are usually expressed at levels lower than P2Y1 sites, however the promoter region of the P2Y2 receptors has not yet been studied and little is known about the mechanisms underlying the regulation of the expression of this ATP receptor. We showed that not only UTP and ATP are the most potent and naturally occurring agonist for P2Y2 sites, but also guanosine induced an up-regulation of astrocyte P2Y2 receptor mRNA evaluated by Northern blot analysis. We also focused our attention on this nucleoside since in our previous studies it was reported to be released by cultured astrocytes and to exert different neuroprotective effects. UTP and guanosine-evoked P2Y2 receptor up-regulation in rat brain cultured astrocytes was linked to an increased P2Y2-mediated intracellular calcium response, thus suggesting an increased P2Y2 activity. Actinomycin D, a RNA polymerase inhibitor, abrogated both UTP and guanosine-mediated P2Y2 up-regulation, thus indicating that de novo transcription was required. The effect of UTP and guanosine was also evaluated in astrocytes pretreated with different inhibitors of signal transduction pathways including ERK, PKC and PKA reported to be involved in the regulation of other cell surface receptor mRNAs. The results show that ERK1-2/MAPK pathway play a key role in the P2Y2 receptor up-regulation mediated by either UTP or guanosine. Moreover, our data suggest that PKA is also involved in guanosine-induced transcriptional activation of P2Y2 mRNA and that increased intracellular calcium levels and PKC activation may also mediate P2Y2 receptor up-regulation triggered by UTP. The extracellular release of ATP under physiological and pathological conditions has been widely studied. On the contrary, little is known about the release of

  8. Central P2Y12 receptor blockade alleviates inflammatory and neuropathic pain and cytokine production in rodents

    PubMed Central

    Horváth, Gergely; Gölöncsér, Flóra; Csölle, Cecilia; Király, Kornél; Andó, Rómeó D.; Baranyi, Mária; Koványi, Bence; Máté, Zoltán; Hoffmann, Kristina; Algaier, Irina; Baqi, Younis; Müller, Christa E.; Von Kügelgen, Ivar; Sperlágh, Beáta

    2014-01-01

    In this study the role of P2Y12 receptors (P2Y12R) was explored in rodent models of inflammatory and neuropathic pain and in acute thermal nociception. In correlation with their activity to block the recombinant human P2Y12R, the majority of P2Y12R antagonists alleviated mechanical hyperalgesia dose-dependently, following intraplantar CFA injection, and after partial ligation of the sciatic nerve in rats. They also caused an increase in thermal nociceptive threshold in the hot plate test. Among the six P2Y12R antagonists evaluated in the pain studies, the selective P2Y12 receptor antagonist PSB-0739 was most potent upon intrathecal application. P2Y12R mRNA and IL-1β protein were time-dependently overexpressed in the rat hind paw and lumbar spinal cord following intraplantar CFA injection. This was accompanied by the upregulation of TNF-α, IL-6 and IL-10 in the hind paw. PSB-0739 (0.3 mg/kg i.t.) attenuated CFA-induced expression of cytokines in the hind paw and of IL-1β in the spinal cord. Subdiaphragmatic vagotomy and the α7 nicotinic acetylcholine receptor antagonist MLA occluded the effect of PSB-0739 (i.t.) on pain behavior and peripheral cytokine induction. Denervation of sympathetic nerves by 6-OHDA pretreatment did not affect the action of PSB-0739. PSB-0739, in an analgesic dose, did not influence motor coordination and platelet aggregation. Genetic deletion of the P2Y12R in mice reproduced the effect of P2Y12R antagonists on mechanical hyperalgesia in inflammatory and neuropathic pain models, on acute thermal nociception and on the induction of spinal IL-1β. Here we report the robust involvement of the P2Y12R in inflammatory pain. The anti-hyperalgesic effect of P2Y12R antagonism could be mediated by the inhibition of both central and peripheral cytokine production and involves α7-receptor mediated efferent pathways. PMID:24971933

  9. Autocrine Regulation of UVA-Induced IL-6 Production via Release of ATP and Activation of P2Y Receptors

    PubMed Central

    Kawano, Ayumi; Kadomatsu, Remi; Ono, Miyu; Kojima, Shuji; Tsukimoto, Mitsutoshi; Sakamoto, Hikaru

    2015-01-01

    Extracellular nucleotides, such as ATP, are released from cells in response to various stimuli and act as intercellular signaling molecules through activation of P2 receptors. Exposure to the ultraviolet radiation A (UVA) component of sunlight causes molecular and cellular damage, and in this study, we investigated the involvement of extracellular nucleotides and P2 receptors in the UVA-induced cellular response. Human keratinocyte-derived HaCaT cells were irradiated with a single dose of UVA (2.5 J/cm2), and ATP release and interleukin (IL)-6 production were measured. ATP was released from cells in response to UVA irradiation, and the release was blocked by pretreatment with inhibitors of gap junction hemichannels or P2X7 receptor antagonist. IL-6 production was increased after UVA irradiation, and this increase was inhibited by ecto-nucleotidase or by antagonists of P2Y11 or P2Y13 receptor. These results suggest that UVA-induced IL-6 production is mediated by release of ATP through hemichannels and P2X7 receptor, followed by activation of P2Y11 and P2Y13 receptors. Interestingly, P2Y11 and P2Y13 were associated with the same pattern of IL-6 production, though they trigger different intracellular signaling cascades: Ca2+-dependent and PI3K-dependent, respectively. Thus, IL-6 production in response to UVA-induced ATP release involves at least two distinct pathways, mediated by activation of P2Y11 and P2Y13 receptors. PMID:26030257

  10. Comparison of VerifyNow P2Y12 and thrombelastography for assessing clopidogrel response in stroke patients in China.

    PubMed

    Lv, Hui-Hui; Wu, Shuai; Liu, Xu; Yang, Xiao-Li; Xu, Jian-Feng; Guan, Yang-Tai; Dong, Qiang; Zheng, S Lilly; Jiang, Jian-Ming; Li, Shi-Xu; Luo, Zheng; Li, Li; An, Li-Xian; Han, Yan

    2016-02-01

    Poor response to clopidogrel is often associated with recurrent ischemic events, and reliable platelet function tests are needed to identify clopidogrel low response (CLR). The aim of the study was to compare the consistency of VerifyNow P2Y12 and thrombelastography (TEG) in acute ischemic stroke patients treated with clopidogrel. Patients hospitalized in Changhai Hospital from August 2012 to September 2013 and assigned to treatment with a daily 75-mg dose of clopidogrel. The blood samples were taken on the 5-7th day to assess the capability of VerifyNow P2Y12 and TEG for evaluation of clopidogrel response, and all instrument parameters were used to perform correlation analysis. Patients with CLR were detected by using the methods and criteria published earlier (PRU ≥ 230 assayed by VerifyNow P2Y12 or TEG-Inhib% ≤30 % measured by TEG). Totally 58 patients were enrolled for the study and there were wide varieties in parameters of VerifyNow P2Y12 and TEG. Results showed a total of 17 and 9 patients, respectively, identified as CLR assessed by VerifyNow P2Y12 and TEG, but only three patients were detected to be clopidogrel low responders with both tests. The kappa consistency analysis showed poor consistency between VerifyNow P2Y12 and TEG results in terms of CLR (Kappa = -0.0349, p = 0.7730). Linear regression also demonstrated poor correlation between VerifyNow-PRU/VerifyNow-Inhib% and TEG-Inhib% (p = 0.07901 and p = 0.3788, respectively). Our study demonstrated that there was poor correlation between VerifyNow P2Y12 and TEG results, and VerifyNow P2Y12 showed a larger proportion of CLR than TEG. PMID:26520845

  11. The G Protein-coupled Receptor P2Y14 Influences Insulin Release and Smooth Muscle Function in Mice*

    PubMed Central

    Meister, Jaroslawna; Le Duc, Diana; Ricken, Albert; Burkhardt, Ralph; Thiery, Joachim; Pfannkuche, Helga; Polte, Tobias; Grosse, Johannes; Schöneberg, Torsten; Schulz, Angela

    2014-01-01

    UDP sugars were identified as extracellular signaling molecules, assigning a new function to these compounds in addition to their well defined role in intracellular substrate metabolism and storage. Previously regarded as an orphan receptor, the G protein-coupled receptor P2Y14 (GPR105) was found to bind extracellular UDP and UDP sugars. Little is known about the physiological functions of this G protein-coupled receptor. To study its physiological role, we used a gene-deficient mouse strain expressing the bacterial LacZ reporter gene to monitor the physiological expression pattern of P2Y14. We found that P2Y14 is mainly expressed in pancreas and salivary glands and in subpopulations of smooth muscle cells of the gastrointestinal tract, blood vessels, lung, and uterus. Among other phenotypical differences, knock-out mice showed a significantly impaired glucose tolerance following oral and intraperitoneal glucose application. An unchanged insulin tolerance suggested altered pancreatic islet function. Transcriptome analysis of pancreatic islets showed that P2Y14 deficiency significantly changed expression of components involved in insulin secretion. Insulin secretion tests revealed a reduced insulin release from P2Y14-deficient islets, highlighting P2Y14 as a new modulator of proper insulin secretion. PMID:24993824

  12. An intact PDZ motif is essential for correct P2Y12 purinoceptor traffic in human platelets

    PubMed Central

    Nisar, Shaista; Daly, Martina E.; Federici, Augusto B.; Artoni, Andrea; Mumford, Andrew D.; Watson, Stephen P.

    2011-01-01

    The platelet P2Y12 purinoceptor (P2Y12R), which plays a crucial role in hemostasis, undergoes internalization and subsequent recycling to maintain receptor responsiveness, processes that are essential for normal platelet function. Here, we observe that P2Y12R function is compromised after deletion or mutation of the 4 amino acids at the extreme C-terminus of this receptor (ETPM), a putative postsynaptic density 95/disc large/zonula occludens-1 (PDZ)–binding motif. In cell line models, removal of this sequence or mutation of one of its core residues (P341A), attenuates receptor internalization and receptor recycling back to the membrane, thereby blocking receptor resensitization. The physiologic significance of these findings in the regulation of platelet function is shown by identification of a patient with a heterozygous mutation in the PDZ binding sequence of their P2Y12R (P341A) that is associated with reduced expression of the P2Y12R on the cell surface. Importantly, platelets from this subject showed significantly compromised P2Y12R recycling, emphasizing the importance of the extreme C-terminus of this receptor to ensure correct receptor traffic. PMID:21937696

  13. An intact PDZ motif is essential for correct P2Y12 purinoceptor traffic in human platelets.

    PubMed

    Nisar, Shaista; Daly, Martina E; Federici, Augusto B; Artoni, Andrea; Mumford, Andrew D; Watson, Stephen P; Mundell, Stuart J

    2011-11-17

    The platelet P2Y(12) purinoceptor (P2Y(12)R), which plays a crucial role in hemostasis, undergoes internalization and subsequent recycling to maintain receptor responsiveness, processes that are essential for normal platelet function. Here, we observe that P2Y(12)R function is compromised after deletion or mutation of the 4 amino acids at the extreme C-terminus of this receptor (ETPM), a putative postsynaptic density 95/disc large/zonula occludens-1 (PDZ)-binding motif. In cell line models, removal of this sequence or mutation of one of its core residues (P341A), attenuates receptor internalization and receptor recycling back to the membrane, thereby blocking receptor resensitization. The physiologic significance of these findings in the regulation of platelet function is shown by identification of a patient with a heterozygous mutation in the PDZ binding sequence of their P2Y(12)R (P341A) that is associated with reduced expression of the P2Y(12)R on the cell surface. Importantly, platelets from this subject showed significantly compromised P2Y(12)R recycling, emphasizing the importance of the extreme C-terminus of this receptor to ensure correct receptor traffic. PMID:21937696

  14. P2Y12-ADP receptor antagonists: Days of future and past.

    PubMed

    Laine, Marc; Paganelli, Franck; Bonello, Laurent

    2016-05-26

    Antiplatelet therapy is the cornerstone of the therapeutic arsenal in coronary artery disease. Thanks to a better understanding in physiology, pharmacology and pharmacogenomics huge progress were made in the field of platelet reactivity inhibition thus allowing the expansion of percutaneous coronary intervention. Stent implantation requires the combination of two antiplatelet agents acting in a synergistic way. Asprin inhibit the cyclo-oxygenase pathway of platelet activation while clopidogrel is a P2Y12 adenosine diphosphate (ADP)-receptor antagonist. This dual antiplatelet therapy has dramatically improved the prognosis of stented patients. However, due to pharmacological limitations of clopidogrel (interindividual variability in its biological efficacy, slow onset of action, mild platelet reactivity inhibition) ischemic recurrences remained high following stent implantation especially in acute coronary syndrome patients. Thus, more potent P2Y12-ADP receptor inhibitors were developped including prasugrel, ticagrelor and more recently cangrelor to overcome these pitfalls. These new agents reduced the rate of thrombotic events in acute coronary syndrome patients at the cost of an increased bleeding risk. The abundance in antiplatelet agents allow us to tailor our strategy based on the thrombotic/bleeding profile of each patient. Recently, the ACCOAST trial cast a doubt on the benefit of pre treatment in non-ST segment elevation acute coronary syndrome. The aim of the present review is to summarize the results of the main studies dealing with antiplatelet therapy in stented/acute coronary syndromes patients. PMID:27231519

  15. A theoretical study of models for X sub 2 Y sub 2 zintl ions

    SciTech Connect

    Cave, R.J.; Davidson, E.R. ); Sautet, P.; Canadell, E.; Eisenstein, O. )

    1989-10-11

    Ab initio and extended Hueckel calculations have been used to discuss the bonding scheme in X{sub 2}Y{sub 2} neutral and ionic main group clusters. A qualitative analysis suggests that two different electron counts, 20 and 22, are possible for the butterfly structures of these systems. This results from two orbital crossings in the correlation diagram for the tetrahedral (T{sub d}) {yields} butterfly (C{sub 2{nu}}) {yields} square-planar (D{sub 2h}) transformation. Detailed ab initio computations substantiate this analysis and show that the 20-electron butterfly structure becomes increasingly favored over the tetrahedral one in X{sub 2}Y{sub 2} clusters when the 2 atoms have increasing electronegativity difference. These results are in agreement with the known structures for the Pb{sub 2}Sb{sub 2}{sup 2{minus}} and Sb{sub 2}Bi{sub 2}{sup 2{minus}} clusters (tetrahedral-like) and the Tl{sub 2}Te{sub 2}{sup 2{minus}} one (butterfly-like).

  16. Effect of thermal cycling on ZrO2-Y2O3 thermal barrier coatings

    NASA Technical Reports Server (NTRS)

    Mcdonald, G.; Hendricks, R. C.

    1980-01-01

    The paper studies the comparative life of plasma-sprayed ZrO2-Y2O3 thermal barrier coatings on NiCrAlY bond coats on Rene 41 in short (4 min) and long (57 min) thermal cycles at 1040 C in a 0.3-Mach flame. Attention is given to determining the effect of short- and long-duration cycles on ZrO2-Y2O3 coatings, the cause of any cycle frequency effects, and methods to improve tolerance to thermal stress. Short cycles greatly reduced the life of the ceramic coating in terms of time at temperatures as compared to longer cycles, the failed coating indicating compressive failure. The experiments and stress calculations show that repeatedly subjecting a ceramic coating to high rates of initial heating has a more destructive influence on the coating than sustained operation at temperature. The effect of such thermal compressive stresses might be minimized through coating deposition and thickness control and by turbine cycle measurement to keep starting heating rates below critical values.

  17. P2Y12-ADP receptor antagonists: Days of future and past

    PubMed Central

    Laine, Marc; Paganelli, Franck; Bonello, Laurent

    2016-01-01

    Antiplatelet therapy is the cornerstone of the therapeutic arsenal in coronary artery disease. Thanks to a better understanding in physiology, pharmacology and pharmacogenomics huge progress were made in the field of platelet reactivity inhibition thus allowing the expansion of percutaneous coronary intervention. Stent implantation requires the combination of two antiplatelet agents acting in a synergistic way. Asprin inhibit the cyclo-oxygenase pathway of platelet activation while clopidogrel is a P2Y12 adenosine diphosphate (ADP)-receptor antagonist. This dual antiplatelet therapy has dramatically improved the prognosis of stented patients. However, due to pharmacological limitations of clopidogrel (interindividual variability in its biological efficacy, slow onset of action, mild platelet reactivity inhibition) ischemic recurrences remained high following stent implantation especially in acute coronary syndrome patients. Thus, more potent P2Y12-ADP receptor inhibitors were developped including prasugrel, ticagrelor and more recently cangrelor to overcome these pitfalls. These new agents reduced the rate of thrombotic events in acute coronary syndrome patients at the cost of an increased bleeding risk. The abundance in antiplatelet agents allow us to tailor our strategy based on the thrombotic/bleeding profile of each patient. Recently, the ACCOAST trial cast a doubt on the benefit of pre treatment in non-ST segment elevation acute coronary syndrome. The aim of the present review is to summarize the results of the main studies dealing with antiplatelet therapy in stented/acute coronary syndromes patients. PMID:27231519

  18. Suppression of exchange bias effect in maghemite nanoparticles functionalized with H2Y

    NASA Astrophysics Data System (ADS)

    Guivar, Juan A. Ramos; Morales, M. A.; Litterst, F. Jochen

    2016-12-01

    The structural, vibrational, morphological and magnetic properties of maghemite (γ-Fe2O3) nanoparticles functionalized with polar molecules EDTA(or H4Y) and H2Y are reported. The samples were functionalized before and after total synthesis of γ-Fe2O3 nanoparticles. The molecules are anchored on the monodentate mode on the nanoparticles surface. Transmission electron microscopy (TEM) revealed the formation of maghemite nanoparticles with small diameter of 4 nm for the sample functionalized upon synthesis and 7.6 and 6.9 nm for the samples functionalized with EDTA and H2Y after the formation of nanoparticles. Exchange bias phenomena were observed in some of the samples functionalized with EDTA at temperatures below 70 K. The presence of the bias effect was discussed in terms of the formation of a thin layer of a secondary phase like lepidocrocite, and the absence of this effect was explained in terms of the chemisorption of carboxylic groups from EDTA which suppressed the canting. Studies of Mössbauer spectroscopy as a function of temperature showed slow relaxation effects and allowed discussion of the secondary phase. In the M-T curves a maximum around 116 K was associated with this secondary phase also in agreement with the Mössbauer studies. The dynamic properties were studied by AC susceptibility, the out of phase signal revealed a spin glass like regime below 36.5 K.

  19. P2Y12 Receptor Antagonists and Morphine: A Dangerous Liaison?

    PubMed

    Giannopoulos, Georgios; Deftereos, Spyridon; Kolokathis, Fotios; Xanthopoulou, Ioanna; Lekakis, John; Alexopoulos, Dimitrios

    2016-09-01

    P2Y12 receptor antagonists, concurrently administered with aspirin in what has come to be commonly called dual antiplatelet therapy, are a mainstay of treatment for patients with acute coronary syndromes. Morphine, on the contrary, is a commonly used drug in the acute phase of acute coronary syndromes to relieve pain-with the added potential benefit of attenuating acutely raised sympathetic tone. In current guidelines, though, morphine is recommended with decreasing strength of recommendation. One reason is that it raises concern regarding the potentially significant interaction with antiplatelet agents, leading to impaired inhibition of platelet activation. In any case, it is still considered a mandatory part of the inventory of available medications in prehospital acute myocardial infarction management. The goal of the present review is to present published evidence on morphine and its potential interactions with P2Y12 receptor antagonists, as well as on the central issue of whether such interactions may underlie clinically significant effects on patient outcomes. PMID:27586412

  20. Dynamin reduces Pyk2 Y402 phosphorylation and SRC binding in osteoclasts.

    PubMed

    Bruzzaniti, Angela; Neff, Lynn; Sandoval, Amanda; Du, Liping; Horne, William C; Baron, Roland

    2009-07-01

    Signaling via the Pyk2-Src-Cbl complex downstream of integrins contributes to the assembly, organization, and dynamics of podosomes, which are the transient adhesion complexes of highly motile cells such as osteoclasts and dendritic cells. We previously demonstrated that the GTPase dynamin is associated with podosomes, regulates actin flux in podosomes, and promotes bone resorption by osteoclasts. We report here that dynamin associates with Pyk2, independent of dynamin's GTPase activity, and reduces Pyk2 Y402 phosphorylation in a GTPase-dependent manner, leading to decreased Src binding to Pyk2. Overexpressing dynamin decreased the macrophage colony-stimulating factor- and adhesion-induced phosphorylation of Pyk2 in osteoclastlike cells, suggesting that dynamin is likely to regulate Src-Pyk2 binding downstream of integrins and growth factor receptors with important cellular consequences. Furthermore, catalytically active Src promotes dynamin-Pyk2 association, and mutating specific Src-phosphorylated tyrosine residues in dynamin blunts the dynamin-induced decrease in Pyk2 phosphorylation. Thus, since Src binds to Pyk2 through its interaction with phospho-Y402, our results suggest that Src activates a negative-feedback loop downstream of integrin engagement and other stimuli by promoting both the binding of dynamin to Pyk2-containing complexes and the dynamin-dependent decrease in Pyk2 Y402 phosphorylation, ultimately leading to the dissociation of Src from Pyk2. PMID:19380485

  1. Dynamin Reduces Pyk2 Y402 Phosphorylation and Src Binding in Osteoclasts ▿ †

    PubMed Central

    Bruzzaniti, Angela; Neff, Lynn; Sandoval, Amanda; Du, Liping; Horne, William C.; Baron, Roland

    2009-01-01

    Signaling via the Pyk2-Src-Cbl complex downstream of integrins contributes to the assembly, organization, and dynamics of podosomes, which are the transient adhesion complexes of highly motile cells such as osteoclasts and dendritic cells. We previously demonstrated that the GTPase dynamin is associated with podosomes, regulates actin flux in podosomes, and promotes bone resorption by osteoclasts. We report here that dynamin associates with Pyk2, independent of dynamin's GTPase activity, and reduces Pyk2 Y402 phosphorylation in a GTPase-dependent manner, leading to decreased Src binding to Pyk2. Overexpressing dynamin decreased the macrophage colony-stimulating factor- and adhesion-induced phosphorylation of Pyk2 in osteoclastlike cells, suggesting that dynamin is likely to regulate Src-Pyk2 binding downstream of integrins and growth factor receptors with important cellular consequences. Furthermore, catalytically active Src promotes dynamin-Pyk2 association, and mutating specific Src-phosphorylated tyrosine residues in dynamin blunts the dynamin-induced decrease in Pyk2 phosphorylation. Thus, since Src binds to Pyk2 through its interaction with phospho-Y402, our results suggest that Src activates a negative-feedback loop downstream of integrin engagement and other stimuli by promoting both the binding of dynamin to Pyk2-containing complexes and the dynamin-dependent decrease in Pyk2 Y402 phosphorylation, ultimately leading to the dissociation of Src from Pyk2. PMID:19380485

  2. Evaluation of SD-208, a TGF-β-RI Kinase Inhibitor, as an Anticancer Agent in Retinoblastoma.

    PubMed

    Fadakar, Puran; Akbari, Abolfazl; Ghassemi, Fariba; Mobini, Gholam Reza; Mohebi, Masoumeh; Bolhassani, Manzar; Abed Khojasteh, Hoda; Heidari, Mansour

    2016-06-01

    Retinoblastoma is the most common intraocular tumor in children resulting from genetic alterations and transformation of mature retinal cells. The objective of this study was to investigate the effects of SD-208, TGF-β-RI kinase inhibitor, on the expression of some miRNAs including a miR-17/92 cluster in retinoblastoma cells. Prior to initiate this work, the cell proliferation was studied by Methyl Thiazolyl Tetrazolium (MTT) and bromo-2'-deoxyuridine (BrdU) assays. Then, the expression patterns of four miRNAs (18a, 20a, 22, and 34a) were investigated in the treated SD-208 (0.0, 1, 2 and 3 µM) and untreated Y-79 cells. A remarkable inhibition of the cell proliferation was found in Y-79 cells treated with SD-208 versus untreated cells. Also, the expression changes were observed in miRNAs 18a, 20a, 22 and 34a in response to SD-208 treatment (P<0.05). The findings of the present study suggest that the anti-cancer effect of SD-208 may be exerted due to the regulation of specific miRNAs, at least in this particular retinoblastoma cell line. To the best of the researchers' knowledge, this is the first report demonstrating that the SD-208 could alter the expression of tumor suppressive miRNAs as well as oncomiRs in vitro. In conclusion, the present data suggest that SD-208 could be an alternative agent in retinoblastoma treatment. PMID:27306340

  3. Caveolin-1 Regulates the P2Y2 Receptor Signaling in Human 1321N1 Astrocytoma Cells.

    PubMed

    Martinez, Namyr A; Ayala, Alondra M; Martinez, Magdiel; Martinez-Rivera, Freddyson J; Miranda, Jorge D; Silva, Walter I

    2016-06-01

    Damage to the CNS can cause a differential spatio-temporal release of multiple factors, such as nucleotides, ATP and UTP. The latter interact with neuronal and glial nucleotide receptors. The P2Y2 nucleotide receptor (P2Y2R) has gained prominence as a modulator of gliotic responses after CNS injury. Still, the molecular mechanisms underlying these responses in glia are not fully understood. Membrane-raft microdomains, such as caveolae, and their constituent caveolins, modulate receptor signaling in astrocytes; yet, their role in P2Y2R signaling has not been adequately explored. Hence, this study evaluated the role of caveolin-1 (Cav-1) in modulating P2Y2R subcellular distribution and signaling in human 1321N1 astrocytoma cells. Recombinant hP2Y2R expressed in 1321N1 cells and Cav-1 were found to co-fractionate in light-density membrane-raft fractions, co-localize via confocal microscopy, and co-immunoprecipitate. Raft localization was dependent on ATP stimulation and Cav-1 expression. This hP2Y2R/Cav-1 distribution and interaction was confirmed with various cell model systems differing in the expression of both P2Y2R and Cav-1, and shRNA knockdown of Cav-1 expression. Furthermore, shRNA knockdown of Cav-1 expression decreased nucleotide-induced increases in the intracellular Ca(2+) concentration in 1321N1 and C6 glioma cells without altering TRAP-6 and carbachol Ca(2+) responses. In addition, Cav-1 shRNA knockdown also decreased AKT phosphorylation and altered the kinetics of ERK1/2 activation in 1321N1 cells. Our findings strongly suggest that P2Y2R interaction with Cav-1 in membrane-raft caveolae of 1321N1 cells modulates receptor coupling to its downstream signaling machinery. Thus, P2Y2R/Cav-1 interactions represent a novel target for controlling P2Y2R function after CNS injury. PMID:27129210

  4. Refractive Error and Ocular Parameters: Comparison of Two SD-OCT Systems

    PubMed Central

    Ostrin, Lisa A.; Yuzuriha, Jill; Wildsoet, Christine F.

    2015-01-01

    Purpose Spectral domain optical coherence tomography (SD-OCT) was used to examine the influence of refractive error (RE) on foveal retinal and choroidal thicknesses and scleral canal width (SCW). The performance of the Cirrus and Bioptigen SD-OCT instruments was compared in the same eyes. Methods Both eyes of forty healthy human subjects, ages 22 to 38 years, were dilated and imaged, with the Cirrus OCT, using 6 mm 5-line rasters collapsed into one line, one centered on the fovea and one bisecting the optic nerve head. Seventy-two of the same eyes were imaged with the Bioptigen OCT, using 6 mm × 6 mm scans, one centered on the fovea and one on the optic nerve head. Subfoveal retinal and choroidal thicknesses and SCW were measured. Axial lengths (AL) and REs were obtained using an IOLMaster and a Grand Seiko autorefractor, respectively. Results Only right eyes were included in analyses. Spherical equivalent REs ranged from −12.18 to +8.12 D (mean: −3.44 ± 4.06 D), and ALs ranged from 20.56 to 29.17 mm (mean: 24.86 ± 1.91 mm). Myopia was associated with relatively thin choroids at the fovea (p<0.05) but normal retinal thickness. SCW was significantly correlated with AL as measured with the Bioptigen OCT (p<0.05). Retinal and choroidal thicknesses recorded with the Bioptigen OCT tended to be smaller than values obtained with the Cirrus OCT (mean difference: 5.63 and 24.76 µm, respectively), while the converse was true for the SCW (mean difference: 25.45 µm). Conclusions The finding that high myopes tend to have a thinner subfoveal choroid is consistent with previous studies. That high myopia was linked to enlarged scleral canals may help to explain the increased risk of glaucoma in myopia. Observed differences obtained with the Cirrus and Bioptigen instruments urge caution in comparing results collected with different instruments. PMID:25785537

  5. Intravenous Toxicity Study of Water-soluble Ginseng Pharmacopuncture in SD Rats

    PubMed Central

    Yu, Jun-Sang; Sun, Seung-Ho; Lee, Kwang-Ho; Kwon, Ki-Rok

    2015-01-01

    Objectives: Radix Ginseng has been used for thousands of years to treat a wide variety of diseases. Radix ginseng has also been used as a traditional medicine for boosting Qi energy and tonifying the spleen and lungs. Traditionally, its effect could be obtained orally. Nowadays, a new method, the injection of herbal medicine, is being used. This study was performed to investigate the single-dose intravenous toxicity of water-soluble ginseng pharmacopuncture (WSGP) in Sprague-Dawley (SD) rats. Methods: All experiments were carried out at Biotoxtech, an institute authorized to perform non-clinical studies under the regulation of Good Laboratory Practice (GLP). At the age of six weeks, 40 SD rats, 20 male rats and 20 female rats, were allocated into one of 4 groups according to the dosages they would receive. The WSGP was prepared in the Korean Pharmacopuncture Institute under the regulation of Korea-Good Manufacturing Practice (K-GMP). Dosages of WSGP were 0.1, 0.5 and 1.0 mL/animal for the experimental groups, and normal saline was administered to the control group. The rat's general conditions and body weights, the results of their hematological and biochemistry tests, and their necropsy and histopathological findings were investigated to identify the toxicological effect of WSGP injected intravenously. The effect was examined for 14 days after the WSGP injection. This study was performed under the approval of the Institutional Animal Ethics Committee of Biotoxtech. Results: No deaths were found in this single-dose toxicity test on the intravenous injection of WSGP, and no significant changes in the rat's general conditions and body weights, the results on their hematological and biochemistry test, and their necropsy findings were observed during the test. The local area of the injection site showed minial change. The lethal dose was assumed to be over 1.0 mL/animal in both sexes. Conclusion: These results indicate that WSGP is safe at dosages up to 1 m

  6. Diversity of DIS, SD and psi hairpins in HIV-1 isolates of group M: in silico study.

    PubMed

    Zarudnaya, M I; Potyahaylo, A L; Kolomiets, I N; Hovorun, D M

    2007-01-01

    The primary sequence and secondary structure of the region encompassing DIS, SD and psi hairpins in HIV-1 genomic RNAs have been analyzed for 731 group M isolates from NCBI database. The secondary structures have been predicted by the m fold program (M. Zuker). Though the primary sequence of the region studied was found to be highly heterogeneous, this region is folded into DIS, SD and psi hairpins (DIS-, SD- and psi-like hairpins) in 96% of the isolates studied. The phylogenetic analysis showed that the most frequent variants of DIS hairpin (DIS(Lai), DIS(Mal) and DIS(C)) tolerate certain base changes. Particularly, base changes at stem position 23 occur 5 and 33 times more frequently in DIS(Lai) than in DIS(Mal) and DIS(C), respectively, while A insertion at the 5'end of apical loop is tolerated in DIS(Mal) and DIS(C) but not in DIS(Lai). We have revealed that the bottom base pair substitution G-C --> A-U in SD hairpin is highly specific for subtype D isolates. All variants of DIS, SD and psi hairpins found in our database are discussed, systematized and presented in schemes of hypothetical transitions between variants via a single base change. Most variants of DIS and psi hairpins were found to adopt several conformations. PMID:18030736

  7. The effect of pH on the corrosion behavior of intermetallic compounds Ni{sub 3}(Si,Ti) and Ni{sub 3}(Si,Ti) + 2Mo in sodium chloride solutions

    SciTech Connect

    Priyotomo, Gadang Nuraini, Lutviasari; Kaneno, Yasuyuki

    2015-12-29

    The corrosion behavior of the intermetallic compounds, Ni{sub 3}(Si,Ti) (L1{sub 2}: single phase) and Ni{sub 3}(Si,Ti) + 2Mo (L1{sub 2} and (L12 + Ni{sub ss}) mixture region), has been investigated using an immersion test, electrochemical method and surface analytical method (SEM; scanning electron microscope and EDAX: Energy Dispersive X-ray) in 0.5 kmol/m{sup 3} NaCl solutions at various pH. The corrosion behavior of nickel alloy C-276 was studied under the same experimental conditions as a reference. It was found that the uniform attack was observed on Ni{sub 3}(Si,Ti) for the immersion test at lower pH, while the pitting attack was observed on this compound for this test at neutral solution. Furthermore, Ni{sub 3}(Si,Ti)+2Mo had the preferential dissolution of L1{sub 2} compared to (L1{sub 2} + Ni{sub ss}) mixture region at lower pH, while pitting attack occurred in (L1{sub 2} + Ni{sub ss}) mixture region at neutral solution. For both intermetallic compounds, the magnitude of pitting and uniform attack decrease with increasing pH of solutions. From the immersion test and polarization curves, the corrosion resistance of Ni{sub 3}(Si,Ti)+2Mo is lower than that of Ni{sub 3}(Si,Ti), while the nickel alloy C-276 is the highest one at various pH of solutions. On the other hand, in the lower pH of solutions, the corrosion resistance of tested materials decreased significantly compared to those in neutral and higher pH of solutions.

  8. The estrogenic effects of benzylparaben at low doses based on uterotrophic assay in immature SD rats.

    PubMed

    Hu, Ying; Zhang, Zhaobin; Sun, Libei; Zhu, Desheng; Liu, Qingchun; Jiao, Jian; Li, Jun; Qi, Mingwen

    2013-03-01

    Benzylparaben (BzP), a type of parabens being used as a preservative agent in cosmetics, food, and pharmaceutical products, may be ingested by humans. In this study, we performed an immature uterotrophic assay using Sprague Dawley (SD) rats by intragastric administration to determine the estrogenic effects of BzP and found significant increases in uterine weight with doses of 0.16 mg/kg body weight and higher (P<0.05). The in vivo estrogenicity of BzP was supported by in vitro results from the human estrogen receptor α (hERα)-coactivator recruiting assay and in silico molecular docking analysis performed in this study. The in vitro estrogenic activity of BzP can be observed at concentrations of 1.0×10(-8) M and higher. Molecular docking analysis showed that BzP fits well into the agonist pocket of hERα. The lowest observed effect dose (LOED) (0.16 mg/kg/day) of BzP is much lower than the documented LOEDs of other parabens. Actual risk may exist for people who consume a diet high in BzP or use BzP-laden cosmetics. In addition, we tested the sensitivity of Wistar rats to 17β-estradiol by immature uterotrophic assay, and no obvious uterotrophic response was observed in the rats given doses up to 100 μg/kg body weight. PMID:23220609

  9. Spectrum of {gamma} rays from the decay of SD to normal states in {sup 191}Hg

    SciTech Connect

    Gassmann, D.; Khoo, T.L.; Lauritsen, T.

    1995-08-01

    In B.a.7. we propose that the statistical spectrum emitted from a sharp single excited state serves as a probe of pairing in excited states. A specific test of this proposal is the comparison of the spectra from even-even and odd-even nuclei. Whereas a pair gap exists in an even-even nucleus, it gets filled in an odd-even nucleus. Consequently, low-energy transitions can arise in the latter case, whereas they are calculated to be absent in the former case because very few levels exist in the cold gap region. In addition, transitions between 1.4 - 2.2 MeV, which {open_quotes}jump{close_quotes} across the gap, are predicted to have lower yield in the odd-even nuclei. Serendipitously, decay from a superdeformed state serves as a good initial excited sharp state. We extracted the spectrum pairwise-coincident with SD lines in {sup 191}Hg from Gammasphere data and compared it with the equivalent spectra from the even-even nuclei {sup 192,194}Hg. The differences that are predicted to occur are indeed observed. Thus, the data support our proposal that the reduction of pairing with thermal excitation energy can be probed with statistical decay spectra.

  10. Neutron Skins and Halo Orbits in the sd and pf Shells.

    PubMed

    Bonnard, J; Lenzi, S M; Zuker, A P

    2016-05-27

    The strong dependence of Coulomb energies on nuclear radii makes it possible to extract the latter from calculations of the former. The resulting estimates of neutron skins indicate that two mechanisms are involved. The first one-isovector monopole polarizability-amounts to noting that when a particle is added to a system it drives the radii of neutrons and protons in different directions, tending to equalize the radii of both fluids independently of the neutron excess. This mechanism is well understood and the Duflo-Zuker (small) neutron skin values derived 14 years ago are consistent with recent measures and estimates. The alternative mechanism involves halo orbits whose huge sizes tend to make the neutron skins larger and have a subtle influence on the radial behavior of sd and pf shell nuclei. In particular, they account for the sudden rise in the isotope shifts of nuclei beyond N=28 and the near constancy of radii in the A=40-56 region. This mechanism, detected here for the first time, is not well understood and may well go beyond the Efimov physics usually associated with halo orbits. PMID:27284653

  11. A search for substellar objects orbiting the sdB eclipsing binary HS 0705+6700

    NASA Astrophysics Data System (ADS)

    Qian, S.-B.; Shi, G.; Zola, S.; Koziel-Wierzbowska, D.; Winiarski, M.; Szymanski, T.; Ogloza, W.; Li, L.-J.; Zhu, L.-Y.; Liu, L.; He, J.-J.; Liao, W.-P.; Zhao, E.-G.; Wang, J.-J.; Zhang, J.; Jiang, L.-Q.

    2013-12-01

    By using 78 newly determined timings of light minima together with those collected from the literature, we analysed the changes in the observed minus calculated (O-C) diagram in HS 0705+6700, a short-period (2.3 h) eclipsing binary that consists of a very hot subdwarf B-type (sdB) star and a very cool fully convective red dwarf. We confirmed the cyclic variation in the O-C and refined the parameters of the circumbinary brown dwarf (reported to orbit the binary system in 2009) by analysing the changes for the light travel time effect that arises from the gravitational influence of the third body. Our results indicate the lower mass limit of the third body to be M3 sin i' = 33.7(±1.6) MJup. This companion would be a brown dwarf if its orbital inclination is larger than 27.7° and it is orbiting the central eclipsing binary with an eccentricity e ˜ 0.2 at a separation of about 3.7(±0.1) au.

  12. Classification of SD-OCT Volumes Using Local Binary Patterns: Experimental Validation for DME Detection

    PubMed Central

    Cheung, Carol Y.; Wong, Tien Y.; Lamoureux, Ecosse; Milea, Dan; Mériaudeau, Fabrice; Sidibé, Désiré

    2016-01-01

    This paper addresses the problem of automatic classification of Spectral Domain OCT (SD-OCT) data for automatic identification of patients with DME versus normal subjects. Optical Coherence Tomography (OCT) has been a valuable diagnostic tool for DME, which is among the most common causes of irreversible vision loss in individuals with diabetes. Here, a classification framework with five distinctive steps is proposed and we present an extensive study of each step. Our method considers combination of various preprocessing steps in conjunction with Local Binary Patterns (LBP) features and different mapping strategies. Using linear and nonlinear classifiers, we tested the developed framework on a balanced cohort of 32 patients. Experimental results show that the proposed method outperforms the previous studies by achieving a Sensitivity (SE) and a Specificity (SP) of 81.2% and 93.7%, respectively. Our study concludes that the 3D features and high-level representation of 2D features using patches achieve the best results. However, the effects of preprocessing are inconsistent with different classifiers and feature configurations. PMID:27555965

  13. Effect and mechanism of Salicornia bigelovii Torr. plant salt on blood pressure in SD rats.

    PubMed

    Zhang, Shumeng; Wei, Mingqian; Cao, Chunjie; Ju, Yaoyao; Deng, Yanqun; Ye, Tianwen; Xia, Zufeng; Chen, Meizhen

    2015-03-01

    In this paper, the effect and mechanism of Salicornia bigelovii Torr. plant salt (SPS) on blood pressure in Sprague Dawley (SD) rats were investigated. The results showed that the edible salt induced hypertension, but the SPS did not. Organ indices and Hematoxylin-Eosin (HE) staining analysis indicated that SPS had a protective effect on the kidney and liver. In comparison with the edible salt-treated group, nitric oxide (NO) content, angiotensin-II (Ang-II) and endothelin-1 (ET-1) levels in the serum of the SPS-treated group had no obvious changes, but serum creatinine concentration significantly decreased. Moreover, superoxide dismutase (SOD) and Na(+)-K(+)-ATPase activity increased while malondialdehyde (MDA) content decreased in the SPS-treated group. In conclusion, a long-term high salt intake could lead to hypertension. SPS, as a salt substitute, could increase the body's antioxidant ability to protect the kidney and liver from the damage caused by a high salt intake and effectively avoid the occurrence of hypertension. PMID:25631641

  14. Risk and Vulnerability Analysis of Satellites Due to MM/SD with PIRAT

    NASA Astrophysics Data System (ADS)

    Kempf, Scott; Schafer, Frank Rudolph, Martin; Welty, Nathan; Donath, Therese; Destefanis, Roberto; Grassi, Lilith; Janovsky, Rolf; Evans, Leanne; Winterboer, Arne

    2013-08-01

    Until recently, the state-of-the-art assessment of the threat posed to spacecraft by micrometeoroids and space debris was limited to the application of ballistic limit equations to the outer hull of a spacecraft. The probability of no penetration (PNP) is acceptable for assessing the risk and vulnerability of manned space mission, however, for unmanned missions, whereby penetrations of the spacecraft exterior do not necessarily constitute satellite or mission failure, these values are overly conservative. The newly developed software tool PIRAT (Particle Impact Risk and Vulnerability Analysis Tool) has been developed based on the Schäfer-Ryan-Lambert (SRL) triple-wall ballistic limit equation (BLE), applicable for various satellite components. As a result, it has become possible to assess the individual failure rates of satellite components. This paper demonstrates the modeling of an example satellite, the performance of a PIRAT analysis and the potential for subsequent design optimizations with respect of micrometeoroid and space debris (MM/SD) impact risk.

  15. Immunologic effects of anti-D (WinRho-SD) in children with immune thrombocytopenic purpura.

    PubMed

    Zimmerman, S A; Malinoski, F J; Ware, R E

    1998-02-01

    Intravenous immunoglobulin (IVIG) is an effective treatment for immune thrombocytopenic purpura (ITP) that induces transient blockade of the reticuloendothelial system (RES) with additional effects including alteration of T lymphocyte subsets and suppression of in vitro T lymphocyte proliferation. As anti-D also is an effective treatment for ITP, we investigated its in vitro and in vivo immunologic effects. The in vitro effects of various agents used in ITP therapy were compared using T lymphocyte proliferation assays. Anti-D caused significantly less inhibition than IVIG or dexamethasone, but non-specific protein was as suppressive as IVIG. Six children with chronic ITP were studied following anti-D administration. Patients received a single dose of anti-D (WinRho-SD, 50 microg/kg i.v. over 5 min) and were studied on day 0, day 7, and 1 month later. Anti-D did not affect T lymphocyte subsets including the T cell receptor variable beta repertoire, in vitro T lymphocyte proliferation to mitogens, recall antigens, or interleukin-2, in vitro IgG synthesis induced by pokeweed mitogen, or T lymphocyte cytokine mRNA levels. We conclude that anti-D has no demonstrable in vitro or in vivo effects on lymphocyte enumeration or function, and therefore likely is effective in the treatment of ITP primarily through RES blockade. PMID:9462545

  16. Optimization of a bioactive exopolysaccharide production from endophytic Fusarium solani SD5.

    PubMed

    Mahapatra, Subhadip; Banerjee, Debdulal

    2013-09-12

    Endophytic fungi were less investigated for exopolysaccharide production. In this study endophytic Fusarium solani SD5 was used for optimization of exopolysaccharide production. One variable at a time method and response surface methodology were employed to explore the optimum medium compositions and fermentation conditions. The organism produced maximum exopolysaccharide after 13.68 days of incubation at 28 °C in potato dextrose broth supplemented with (g%/l) glucose, 9.8; yeast extract, 0.69; KCl, 0.05; KH₂PO₄, 0.05 with medium pH 6.46. Use of 50 ml medium in 250 ml Erlenmeyer flask gives highest exopolysaccharide production. The organism produced more than two times higher exopolysaccharide (2.276 ± 0.032 g/l EPS) at optimized condition compared to pre-optimized condition (0.96 ± 0.021). In vivo toxicity test established nontoxic nature of the EPS (≤400 mg EPS/Kg of body weight). The EPS slightly altered intestinal indigenous bacteria and influenced the growth of beneficial Lactobacillus spp. PMID:23911494

  17. Alpha-cluster spectroscopy in 40Ca and in the sd-shell closure region

    NASA Astrophysics Data System (ADS)

    Reidemeister, G.; Ohkubo, S.; Michel, F.

    1990-01-01

    The low-energy 36(α,α) elastic scattering data of Gaul et al. are analyzed within the frame of the optical model, using energy-independent Woods-Saxon squared or model-independent geometries for the real part of the potential. The optical-model scattering amplitude is decomposed into its barrier and internal wave components to understand the rapid and complicated evolution of the angular distributions with incident energy. The properties of the low-energy bound and quasibound states supported by this potential are compared with those of the states of the deformed 4p-4h rotational band in 40Ca, built on the Jπ=0+, Ex=3.35 MeV state. The possibility of extending this local potential model approach to neighboring nuclei near the sd-shell closure is discussed. A negative-parity band of states with appreciable α-cluster character, starting around the α-particle threshold, is expected to be systematically present in this mass region.

  18. Alleviating anastrozole induced bone toxicity by selenium nanoparticles in SD rats.

    PubMed

    Vekariya, Kiritkumar K; Kaur, Jasmine; Tikoo, Kulbhushan

    2013-04-15

    Aromatase inhibitors like anastrozole play an undisputed key role in the treatment of breast cancer, but on the other hand, various side effects like osteoporosis and increased risk of bone fracture accompany the chronic administration of these drugs. Here we show for the first time that selenium nanoparticles, when given in conjugation to anastrozole, lower the bone toxicity caused by anastrozole and thus reduce the probable damage to the bone. Selenium nanoparticles at a dose of 5μg/ml significantly reduced the cell death caused by anastrozole (1μM) in HOS (human osteoblast) cells. In addition, our results also highlighted that in female SD rat model, SeNPs (0.25, 0.5, 1mg/kg/day) significantly prevented the decrease in bone density and increase in biochemical markers of bone resorption induced by anastrozole (0.2mg/kg/day) treatment. Histopathological examination of the femurs of SeNP treated group revealed ossification, mineralization, calcified cartilaginous deposits and a marginal osteoclastic activity, all of which indicate a marked restorative action, suggesting the protective action of the SeNPs. Interestingly, SeNPs (1mg/kg/day) also exhibited protective effect in ovariectomized rat model, by preventing osteoporosis, which signifies that bone loss due to estrogen deficiency can be effectively overcome by using SeNPs. PMID:23415680

  19. Classification of SD-OCT Volumes Using Local Binary Patterns: Experimental Validation for DME Detection.

    PubMed

    Lemaître, Guillaume; Rastgoo, Mojdeh; Massich, Joan; Cheung, Carol Y; Wong, Tien Y; Lamoureux, Ecosse; Milea, Dan; Mériaudeau, Fabrice; Sidibé, Désiré

    2016-01-01

    This paper addresses the problem of automatic classification of Spectral Domain OCT (SD-OCT) data for automatic identification of patients with DME versus normal subjects. Optical Coherence Tomography (OCT) has been a valuable diagnostic tool for DME, which is among the most common causes of irreversible vision loss in individuals with diabetes. Here, a classification framework with five distinctive steps is proposed and we present an extensive study of each step. Our method considers combination of various preprocessing steps in conjunction with Local Binary Patterns (LBP) features and different mapping strategies. Using linear and nonlinear classifiers, we tested the developed framework on a balanced cohort of 32 patients. Experimental results show that the proposed method outperforms the previous studies by achieving a Sensitivity (SE) and a Specificity (SP) of 81.2% and 93.7%, respectively. Our study concludes that the 3D features and high-level representation of 2D features using patches achieve the best results. However, the effects of preprocessing are inconsistent with different classifiers and feature configurations. PMID:27555965

  20. Incidence and Clinical Features of Early Stent Thrombosis in the Era of New P2y12 Inhibitors (PLATIS-2)

    PubMed Central

    Asher, Elad; Abu-Much, Arsalan; Goldenberg, Ilan; Segev, Amit; Sabbag, Avi; Mazin, Israel; Shlezinger, Meital; Atar, Shaul; Zahger, Doron; Polak, Arthur; Beigel, Roy; Matetzky, Shlomi

    2016-01-01

    Early stent thrombosis (EST) (≤ 30 days after stent implantation) is a relatively rare but deleterious complication of percutaneous coronary intervention (PCI). Administration of newer P2Y12 inhibitors (prasugrel and ticagrelor) combined with aspirin has been shown to reduce the incidence of sub-acute and late stent thrombosis, compared with clopidogrel. We investigated the “real life” incidence of EST in patients from a large acute coronary syndrome (ACS) national registry, where newer P2Y12 inhibitors are widely used. Patients were derived from the ACS Israeli Survey (ACSIS), conducted during 2006, 2008, 2010 and 2013. Major adverse cardiac events (MACE) at 30days were defined as all-cause death, recurrent ACS, EST and stroke.Of the 4717 ACS patients who underwent PCI and stenting, 83% received clopidogrel and 17% newer P2Y12 inhibitors. The rate of EST was similar in both groups (1.7% in the newer P2Y12 inhibitor group vs. 1.4% in the clopidogrel-treated patients, p = 0.42). Results were consistent after multivariate analysis (adjusted HR = 1.06 [p = 0.89]). MACE occurred in 6.4% in the newer P2Y12 inhibitor group compared with 9.2% in the clopidogrel group (P<0.01). However, multivariate logistic regression modeling showed that treatment with newer P2Y12 inhibitors was not significantly associated with the secondary endpoint of MACE when compared with clopidogrel therapy [OR = 1.26 95%CI (0.93–1.73), P = 0.136]. The incidence of "real life" EST at 1month is relatively low, and appears to be similar in patients who receive newer P2Y12 inhibitors as well as in those who receive clopidogrel. PMID:27310147

  1. Discovery, characterization and in vivo activity of pyocin SD2, a protein antibiotic from Pseudomonas aeruginosa

    PubMed Central

    McCaughey, Laura C.; Josts, Inokentijs; Grinter, Rhys; White, Paul; Byron, Olwyn; Tucker, Nicholas P.; Matthews, Jacqueline M.; Kleanthous, Colin; Whitchurch, Cynthia B.; Walker, Daniel

    2016-01-01

    Increasing rates of antibiotic resistance among Gram-negative pathogens such as Pseudomonas aeruginosa means alternative approaches to antibiotic development are urgently required. Pyocins, produced by P. aeruginosa for intraspecies competition, are highly potent protein antibiotics known to actively translocate across the outer membrane of P. aeruginosa. Understanding and exploiting the mechanisms by which pyocins target, penetrate and kill P. aeruginosa is a promising approach to antibiotic development. In this work we show the therapeutic potential of a newly identified tRNase pyocin, pyocin SD2, by demonstrating its activity in vivo in a murine model of P. aeruginosa lung infection. In addition, we propose a mechanism of cell targeting and translocation for pyocin SD2 across the P. aeruginosa outer membrane. Pyocin SD2 is concentrated at the cell surface, via binding to the common polysaccharide antigen (CPA) of P. aeruginosa lipopolysaccharide (LPS), from where it can efficiently locate its outer membrane receptor FpvAI. This strategy of utilizing both the CPA and a protein receptor for cell targeting is common among pyocins as we show that pyocins S2, S5 and SD3 also bind to the CPA. Additional data indicate a key role for an unstructured N-terminal region of pyocin SD2 in the subsequent translocation of the pyocin into the cell. These results greatly improve our understanding of how pyocins target and translocate across the outer membrane of P. aeruginosa. This knowledge could be useful for the development of novel anti-pseudomonal therapeutics and will also support the development of pyocin SD2 as a therapeutic in its own right. PMID:27252387

  2. Discovery, characterization and in vivo activity of pyocin SD2, a protein antibiotic from Pseudomonas aeruginosa.

    PubMed

    McCaughey, Laura C; Josts, Inokentijs; Grinter, Rhys; White, Paul; Byron, Olwyn; Tucker, Nicholas P; Matthews, Jacqueline M; Kleanthous, Colin; Whitchurch, Cynthia B; Walker, Daniel

    2016-08-01

    Increasing rates of antibiotic resistance among Gram-negative pathogens such as Pseudomonas aeruginosa means alternative approaches to antibiotic development are urgently required. Pyocins, produced by P. aeruginosa for intraspecies competition, are highly potent protein antibiotics known to actively translocate across the outer membrane of P. aeruginosa. Understanding and exploiting the mechanisms by which pyocins target, penetrate and kill P. aeruginosa is a promising approach to antibiotic development. In this work we show the therapeutic potential of a newly identified tRNase pyocin, pyocin SD2, by demonstrating its activity in vivo in a murine model of P. aeruginosa lung infection. In addition, we propose a mechanism of cell targeting and translocation for pyocin SD2 across the P. aeruginosa outer membrane. Pyocin SD2 is concentrated at the cell surface, via binding to the common polysaccharide antigen (CPA) of P. aeruginosa lipopolysaccharide (LPS), from where it can efficiently locate its outer membrane receptor FpvAI. This strategy of utilizing both the CPA and a protein receptor for cell targeting is common among pyocins as we show that pyocins S2, S5 and SD3 also bind to the CPA. Additional data indicate a key role for an unstructured N-terminal region of pyocin SD2 in the subsequent translocation of the pyocin into the cell. These results greatly improve our understanding of how pyocins target and translocate across the outer membrane of P. aeruginosa. This knowledge could be useful for the development of novel anti-pseudomonal therapeutics and will also support the development of pyocin SD2 as a therapeutic in its own right. PMID:27252387

  3. Chemical analyses of pore water from boreholes USW SD-6 and USW WT-24, Yucca Mountain, Nevada.

    PubMed

    Yang, In C; Peterman, Zell E; Scofield, Kevin M

    2003-01-01

    Analyses of pore water extracted from cores of boreholes USW SD-6 in the central part and USW WT-24 in the northern part of Yucca Mountain, Nevada, show significant vertical and lateral variations in dissolved-ion concentrations. Analyses of samples of only a few milliliters of pore water extracted by uniaxial or triaxial compression and by ultracentrifugation methods from adjacent core samples are generally in agreement, within the analytical error of 10% to 15%. However, the values of silica for water obtained by ultracentrifugation are consistently lower than values for water obtained by compression. The larger concentrations probably are due to localized pressure solution of silicate minerals during compression. The shallower water from core in borehole USW SD-6 was extracted from nonwelded units collectively referred to as the Paintbrush Tuff nonwelded (PTn). The deeper water was from core in both boreholes USW SD-6 and USW WT-24 in the nonwelded units referred to as the Calico Hills nonwelded (CHn). Significant differences in mean dissolved-ion concentrations in pore water between the PTn and CHn are (1) decreases in Ca, Mg, SO(4), and NO(3) and (2) increases in HCO(3) and (Na+K)/(Ca+Mg) ratios. The decrease in NO(3) and the increase in HCO(3) could be the result of denitrification through the oxidation of organic matter. The decrease in Ca and associated increase in (Na+K)/(Ca+Mg) is the result of ion exchange with zeolites in the CHn in borehole USW WT-24. This effect is not nearly as pronounced in borehole USW SD-6, probably reflecting a smaller amount of zeolitization of the CHn in USW SD-6. Geochemical calculations using the PHREEQC code indicate that the pore water from both boreholes USW SD-6 and USW WT-24 is uniformly undersaturated in anhydrite, gypsum, and amorphous silica, but supersaturated in quartz and chalcedony. The saturation of calcite, aragonite, sepiolite, and dolomite is more variable from sample to sample. PMID:12714300

  4. Aquaporin 4-specific T cells and NMO-IgG cause primary retinal damage in experimental NMO/SD.

    PubMed

    Zeka, Bleranda; Hastermann, Maria; Kaufmann, Nathalie; Schanda, Kathrin; Pende, Marko; Misu, Tatsuro; Rommer, Paulus; Fujihara, Kazuo; Nakashima, Ichiro; Dahle, Charlotte; Leutmezer, Fritz; Reindl, Markus; Lassmann, Hans; Bradl, Monika

    2016-01-01

    Neuromyelitis optica/spectrum disorder (NMO/SD) is a severe, inflammatory disease of the central nervous system (CNS). In the majority of patients, it is associated with the presence of pathogenic serum autoantibodies (the so-called NMO-IgGs) directed against the water channel aquaporin 4 (AQP4), and with the formation of large, astrocyte-destructive lesions in spinal cord and optic nerves. A large number of recent studies using optical coherence tomography (OCT) demonstrated that damage to optic nerves in NMO/SD is also associated with retinal injury, as evidenced by retinal nerve fiber layer (RNFL) thinning and microcystic inner nuclear layer abnormalities. These studies concluded that retinal injury in NMO/SD patients results from secondary neurodegeneration triggered by optic neuritis.However, the eye also contains cells expressing AQP4, i.e., Müller cells and astrocytes in the retina, epithelial cells of the ciliary body, and epithelial cells of the iris, which raised the question whether the eye can also be a primary target in NMO/SD. Here, we addressed this point in experimental NMO/SD (ENMO) induced in Lewis rat by transfer of AQP4268-285-specific T cells and NMO-IgG.We show that these animals show retinitis and subsequent dysfunction/damage of retinal axons and neurons, and that this pathology occurs independently of the action of NMO-IgG. We further show that in the retinae of ENMO animals Müller cell side branches lose AQP4 reactivity, while retinal astrocytes and Müller cell processes in the RNFL/ganglionic cell layers are spared. These changes only occur in the presence of both AQP4268-285-specific T cells and NMO-IgG.Cumulatively, our data show that damage to retinal cells can be a primary event in NMO/SD. PMID:27503347

  5. Microglial P2Y12 is necessary for synaptic plasticity in mouse visual cortex.

    PubMed

    Sipe, G O; Lowery, R L; Tremblay, M-È; Kelly, E A; Lamantia, C E; Majewska, A K

    2016-01-01

    Microglia are the resident immune cells of the brain. Increasingly, they are recognized as important mediators of normal neurophysiology, particularly during early development. Here we demonstrate that microglia are critical for ocular dominance plasticity. During the visual critical period, closure of one eye elicits changes in the structure and function of connections underlying binocular responses of neurons in the visual cortex. We find that microglia respond to monocular deprivation during the critical period, altering their morphology, motility and phagocytic behaviour as well as interactions with synapses. To explore the underlying mechanism, we focused on the P2Y12 purinergic receptor, which is selectively expressed in non-activated microglia and mediates process motility during early injury responses. We find that disrupting this receptor alters the microglial response to monocular deprivation and abrogates ocular dominance plasticity. These results suggest that microglia actively contribute to experience-dependent plasticity in the adolescent brain. PMID:26948129

  6. Microglial P2Y12 is necessary for synaptic plasticity in mouse visual cortex

    PubMed Central

    Sipe, G. O.; Lowery,, R. L.; Tremblay, M-È; Kelly, E. A.; Lamantia, C. E.; Majewska, A. K.

    2016-01-01

    Microglia are the resident immune cells of the brain. Increasingly, they are recognized as important mediators of normal neurophysiology, particularly during early development. Here we demonstrate that microglia are critical for ocular dominance plasticity. During the visual critical period, closure of one eye elicits changes in the structure and function of connections underlying binocular responses of neurons in the visual cortex. We find that microglia respond to monocular deprivation during the critical period, altering their morphology, motility and phagocytic behaviour as well as interactions with synapses. To explore the underlying mechanism, we focused on the P2Y12 purinergic receptor, which is selectively expressed in non-activated microglia and mediates process motility during early injury responses. We find that disrupting this receptor alters the microglial response to monocular deprivation and abrogates ocular dominance plasticity. These results suggest that microglia actively contribute to experience-dependent plasticity in the adolescent brain. PMID:26948129

  7. Effect of thermal cycling on ZrO2-Y2O3 thermal barrier coatings

    NASA Technical Reports Server (NTRS)

    Mcdonald, G.; Hendricks, R. C.

    1980-01-01

    A study was made of the comparative life of plasma sprayed ZrO2-Y2O3 thermal barrier coatings on NiCrAlY bond coats on Rene 41 in short (4 min) and long (57 min) thermal cycles to 1040 C in a 0.3 Mach flame. Short cycles greatly reduced the life of the ceramic coating in terms of time at temperature as compared to longer cycles. Appearance of the failed coating indicated compressive failure. Failure occurred at the bond coat-ceramic coat junction. At heating rates greater than 550 kw/sq m, the calculated coating detachment stress was in the range of literature values of coating adhesive/cohesive strength. Methods are discussed for decreasing the effect of high heating rate by avoiding compressive stress.

  8. P2Y2 receptor agonists for the treatment of dry eye disease: a review

    PubMed Central

    Lau, Oliver C F; Samarawickrama, Chameen; Skalicky, Simon E

    2014-01-01

    Recent advances in the understanding of dry eye disease (DED) have revealed previously unexplored targets for drug therapy. One of these drugs is diquafosol, a uridine nucleotide analog that is an agonist of the P2Y2 receptor. Several randomized controlled trials have demonstrated that the application of topical diquafosol significantly improves objective markers of DED such as corneal and conjunctival fluorescein staining and, in some studies, tear film break-up time and Schirmer test scores. However, this has been accompanied by only partial improvement in patient symptoms. Although evidence from the literature is still relatively limited, early studies have suggested that diquafosol has a role in the management of DED. Additional studies would be helpful to delineate how different subgroups of DED respond to diquafosol. The therapeutic combination of diquafosol with other topical agents also warrants further investigation. PMID:24511227

  9. Credit WCT. Original 2¾" x 2Y4" color negative is housed ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Credit WCT. Original 2-¾" x 2-Y4" color negative is housed in the JPL Photography Laboratory, Pasadena, California. View shows JPL staff member John Morrow loading the grinder hopper. The hopper has a 10 mesh screen to filter out particles too large for the mill. Oxidizer is passed steadily to the hammers by a stainless steel feed screw. Oxidizer may be passed through the mill several times depending on the fineness required by a given propellant formula; the maximum charge is 130 pounds (59.0 Kg). The drum below the mill has an electrically conductive plastic liner which receives the ground oxidizer (JPL negative no. JPL10279AC, 27 January 1989) - Jet Propulsion Laboratory Edwards Facility, Oxidizer Grinder Building, Edwards Air Force Base, Boron, Kern County, CA

  10. P2X and P2Y receptor signaling in red blood cells

    PubMed Central

    Sluyter, Ronald

    2015-01-01

    Purinergic signaling involves the activation of cell surface P1 and P2 receptors by extracellular nucleosides and nucleotides such as adenosine and adenosine triphosphate (ATP), respectively. P2 receptors comprise P2X and P2Y receptors, and have well-established roles in leukocyte and platelet biology. Emerging evidence indicates important roles for these receptors in red blood cells. P2 receptor activation stimulates a number of signaling pathways in progenitor red blood cells resulting in microparticle release, reactive oxygen species formation, and apoptosis. Likewise, activation of P2 receptors in mature red blood cells stimulates signaling pathways mediating volume regulation, eicosanoid release, phosphatidylserine exposure, hemolysis, impaired ATP release, and susceptibility or resistance to infection. This review summarizes the distribution of P2 receptors in red blood cells, and outlines the functions of P2 receptor signaling in these cells and its implications in red blood cell biology. PMID:26579528

  11. Electronic structure and dx2-y2-wave superconductivity in FeS

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Wang, Wan-Sheng; Lu, Hong-Yan; Xiang, Yuan-Yuan; Wang, Qiang-Hua

    2016-03-01

    We perform theoretical studies on the newly discovered superconductor FeS. Using density functional theory, we obtain the electronic structure of FeS. Using maximally localized Wannier functions, we obtain an effective tight-binding model with five Fe 3 d orbitals. Based on this model, we investigate, by the unbiased singular-mode functional renormalization group, the superconductivity derived from correlation effects. We find the Hund's rule coupling plays a key role in triggering superconductivity, and the pairing symmetry is dx2-y2 wave (viewed in the unfolded zone). The gap function is nodal/nodeless on the hole/electron Fermi pockets, similarly to the case in LaOFeP. The nodal gap is in agreement with experiments.

  12. P2Y12 receptor inhibition and LPS-induced coagulation.

    PubMed

    Essex, David W; Rao, A Koneti

    2016-03-01

    Platelets play a major role in the complex interactions involved in blood coagulation via multiple mechanisms. As reported in this issue, Schoergenhofer et al. tested the hypothesis that platelet inhibition by prasugrel, a potent platelet P2Y12 ADP receptor antagonist, attenuates the effect of lipopolysaccharide (LPS) on the blood coagulation system in healthy human subjects. LPS, a bacterial product with potent pro-inflammatory and pro-thrombotic effects, plays a central role in sepsis. It activates monocytes and endothelial cells via Toll-like receptor (TLR) 4 and other TLRs to stimulate production of TF and other pro-coagulant molecules, chemokines and cytokines. Treatment with prasugrel did not decrease biomarkers of coagulaion. A better understanding of the relative roles of platelet and coagulation mechanisms in triggering the pro-thrombotic state may lead to more effective antithrombotic strategies. PMID:26846581

  13. Primordial SdS universe from a 5D vacuum: scalar field fluctuations on Schwarzschild and Hubble horizons

    SciTech Connect

    Aguilar, José Edgar Madriz; Bellini, Mauricio E-mail: mbellini@mdp.edu.ar

    2010-11-01

    We study scalar field fluctuations of the inflaton field in an early inflationary universe on an effective 4D Schwarzschild-de Sitter (SdS) metric, which is obtained after make a planar coordinate transformation on a 5D Ricci-flat Schwarzschild-de Sitter (SdS) static metric. We obtain the important result that the spectrum of fluctuations at zeroth order is independent of the scalar field mass M on Schwarzschild scales, while on cosmological scales it exhibits a mass dependence. However, in the first-order expansion, the spectrum depends of the inflaton mass and the amplitude is linear with the Black-Hole (BH) mass m.

  14. Purinergic P2Y receptors in airway epithelia: from ion transport to immune functions.

    PubMed

    Hao, Yuan; Ko, Wing-hung

    2014-02-25

    The regulated transport of salt and water is essential to the integrated function of many organ systems, including the respiratory, reproductive, and digestive tracts. Airway epithelial fluid secretion is a passive process that is driven by osmotic forces, which are generated by ion transport. The main determinant of a luminally-directed osmotic gradient is the mucosal transport of chloride ions (Cl(-)) into the lumen. As with many epithelial cells, a number of classic signal transduction cascades are involved in the regulation of ion transport. There are two well-known intracellular signaling systems: an increase in intracellular Ca(2+) concentration ([Ca(2+)]i) and an increase in the rate of synthesis of cyclic nucleotides, such as cyclic adenosine monophosphate (cAMP). Therefore, Cl(-) secretion is primarily activated via the opening of apical Ca(2+)- or cAMP-dependent Cl(-) channels at the apical membrane. The opening of basolateral Ca(2+)- or cAMP-activated K(+) channels, which hyperpolarizes the cell to maintain the driving force for Cl(-) exit through apical Cl(-) channels that are constitutively open, is also important in regulating transepithelial ion transport. P2Y receptors are expressed in the apical and/or basolateral membranes of virtually all polarized epithelia to control the transport of fluid and electrolytes. Human airway epithelial cells express multiple nucleotide receptors. Extracellular nucleotides, such as UTP and ATP, are calcium-mobilizing secretagogues. They are released into the extracellular space from airway epithelial cells and act on the same cell in an autocrine fashion to stimulate transepithelial ion transport. In addition, recent data support the role of P2Y receptors in releasing inflammatory cytokines in the bronchial epithelium and other immune cells. PMID:24553865

  15. Mining human genome for novel purinergic P2Y receptors: a sequence analysis and molecular modeling approach.

    PubMed

    Bhatnagar, Sonika; Mishra, Shubhi; Pathak, Ravi

    2011-02-01

    The purinergic P2Y receptors are G-protein coupled receptors (GPCRs) that control many physiological processes by mediating cellular responses to purines, pyrimidines and their analogues. They can be used as potential therapeutic targets in a variety of disease conditions. Therefore, it is critical to identify new members of this family of receptors from the human genome and characterize them for their role in health and disease. In the present work, molecular modeling was carried out for the 21 known P2Y receptors. Binding site analysis was done on the basis of docking and site-directed mutagenesis data. Thus, conserved features of P2Y receptors could be formulated. These features can be used to determine the purinergic nature of potential P2Y receptors in the human genome. We applied this knowledge to human genome GPCR sequences found by sensitive sequence search techniques and identified two orphan receptors, namely GPR34 and GP171 that have all the necessary conserved features of P2Y receptors. PMID:21142848

  16. Characterization of P2X3, P2Y1 and P2Y4 receptors in cultured HEK293-hP2X3 cells and their inhibition by ethanol and trichloroethanol.

    PubMed

    Fischer, Wolfgang; Wirkner, Kerstin; Weber, Marco; Eberts, Christoph; Köles, Laszlo; Reinhardt, Robert; Franke, Heike; Allgaier, Clemens; Gillen, Clemens; Illes, Peter

    2003-05-01

    Membrane currents and changes in the intracellular Ca2+ concentration ([Ca2+]i) were measured in HEK293 cells transfected with the human P2X3 receptor (HEK293-hP2X3). RT-PCR and immunocytochemistry indicated the additional presence of endogenous P2Y1 and to some extent P2Y4 receptors. P2 receptor agonists induced inward currents in HEK293-hP2X3 cells with the rank order of potency alpha,beta-meATP approximately ATP > ADP-beta-S > UTP. A comparable rise in [Ca2+]i was observed after the slow superfusion of ATP, ADP-beta-S and UTP; alpha,beta-meATP was ineffective. These data, in conjunction with results obtained by using the P2 receptor antagonists TNP-ATP, PPADS and MRS2179 indicate that the current response to alpha,beta-meATP is due to P2X3 receptor activation, while the ATP-induced rise in [Ca2+]i is evoked by P2Y1 and P2Y4 receptor activation. TCE depressed the alpha,beta-meATP current in a manner compatible with a non-competitive antagonism. The ATP-induced increase of [Ca2+]i was much less sensitive to the inhibitory effect of TCE than the current response to alpha,beta-meATP. The present study indicates that in HEK293-hP2X3 cells, TCE, but not ethanol, potently inhibits ligand-gated P2X3 receptors and, in addition, moderately interferes with G protein-coupled P2Y1 and P2Y4 receptors. Such an effect may be relevant for the interruption of pain transmission in dorsal root ganglion neurons following ingestion of chloral hydrate or trichloroethylene. PMID:12694404

  17. Alleviating anastrozole induced bone toxicity by selenium nanoparticles in SD rats

    SciTech Connect

    Vekariya, Kiritkumar K.; Kaur, Jasmine; Tikoo, Kulbhushan

    2013-04-15

    Aromatase inhibitors like anastrozole play an undisputed key role in the treatment of breast cancer, but on the other hand, various side effects like osteoporosis and increased risk of bone fracture accompany the chronic administration of these drugs. Here we show for the first time that selenium nanoparticles, when given in conjugation to anastrozole, lower the bone toxicity caused by anastrozole and thus reduce the probable damage to the bone. Selenium nanoparticles at a dose of 5 μg/ml significantly reduced the cell death caused by anastrozole (1 μM) in HOS (human osteoblast) cells. In addition, our results also highlighted that in female SD rat model, SeNPs (0.25, 0.5, 1 mg/kg/day) significantly prevented the decrease in bone density and increase in biochemical markers of bone resorption induced by anastrozole (0.2 mg/kg/day) treatment. Histopathological examination of the femurs of SeNP treated group revealed ossification, mineralization, calcified cartilaginous deposits and a marginal osteoclastic activity, all of which indicate a marked restorative action, suggesting the protective action of the SeNPs. Interestingly, SeNPs (1 mg/kg/day) also exhibited protective effect in ovariectomized rat model, by preventing osteoporosis, which signifies that bone loss due to estrogen deficiency can be effectively overcome by using SeNPs. - Highlights: ► SeNPs significantly reduce bone toxicity in anastrozole treated rats. ► SeNPs successfully prevented osteoporosis in ovariectomized rats. ► SeNP treatment lowered the levels of TRAP and increased the levels of ALKP.

  18. Improved Determination of the Atmospheric Parameters of the Pulsating sdB Star Feige 48

    NASA Astrophysics Data System (ADS)

    Latour, M.; Fontaine, G.; Green, E. M.; Brassard, P.; Chayer, P.

    2014-06-01

    As part of a multifaceted effort to better exploit the asteroseismological potential of the pulsating sdB star Feige 48, we present an improved spectroscopic analysis of that star based on new grids of NLTE, fully line-blanketed model atmospheres. To that end, we gathered four high signal-to-noise ratio time-averaged optical spectra of varying spectral resolutions from 1.0 Å to 8.7 Å, and we made use of the results of four independent studies to fix the abundances of the most important metals in the atmosphere of Feige 48. The mean atmospheric parameters we obtained from our four spectra of Feige 48 are: T eff = 29,850 ± 60 K, log g = 5.46 ± 0.01, and log N(He)/N(H) = -2.88 ± 0.02. We also modeled, for the first time, the He II line at 1640 Å from the STIS archive spectrum of the star, and with this line we found an effective temperature and a surface gravity that match well with the values obtained with the optical data. With some fine tuning of the abundances of the metals visible in the optical domain, we were able to achieve a very good agreement between our best available spectrum and our best-fitting synthetic one. Our derived atmospheric parameters for Feige 48 are in rather good agreement with previous estimates based on less sophisticated models. This underlines the relatively small effects of the NLTE approach combined with line blanketing in the atmosphere of this particular star, implying that the current estimates of the atmospheric parameters of Feige 48 are reliable and secure.

  19. Improved determination of the atmospheric parameters of the pulsating sdB star Feige 48

    SciTech Connect

    Latour, M.; Fontaine, G.; Brassard, P.; Green, E. M.; Chayer, P.

    2014-06-10

    As part of a multifaceted effort to better exploit the asteroseismological potential of the pulsating sdB star Feige 48, we present an improved spectroscopic analysis of that star based on new grids of NLTE, fully line-blanketed model atmospheres. To that end, we gathered four high signal-to-noise ratio time-averaged optical spectra of varying spectral resolutions from 1.0 Å to 8.7 Å, and we made use of the results of four independent studies to fix the abundances of the most important metals in the atmosphere of Feige 48. The mean atmospheric parameters we obtained from our four spectra of Feige 48 are: T {sub eff} = 29,850 ± 60 K, log g = 5.46 ± 0.01, and log N(He)/N(H) = –2.88 ± 0.02. We also modeled, for the first time, the He II line at 1640 Å from the STIS archive spectrum of the star, and with this line we found an effective temperature and a surface gravity that match well with the values obtained with the optical data. With some fine tuning of the abundances of the metals visible in the optical domain, we were able to achieve a very good agreement between our best available spectrum and our best-fitting synthetic one. Our derived atmospheric parameters for Feige 48 are in rather good agreement with previous estimates based on less sophisticated models. This underlines the relatively small effects of the NLTE approach combined with line blanketing in the atmosphere of this particular star, implying that the current estimates of the atmospheric parameters of Feige 48 are reliable and secure.

  20. Heterologous Expression and Characterization of the Manganese-Oxidizing Protein from Erythrobacter sp. Strain SD21

    PubMed Central

    Nakama, Katherine; Medina, Michael; Lien, Ahn; Ruggieri, Jordan; Collins, Krystle

    2014-01-01

    The manganese (Mn)-oxidizing protein (MopA) from Erythrobacter sp. strain SD21 is part of a unique enzymatic family that is capable of oxidizing soluble Mn(II). This enzyme contains two domains, an animal heme peroxidase domain, which contains the catalytic site, followed by a C-terminal calcium binding domain. Different from the bacterial Mn-oxidizing multicopper oxidase enzymes, little is known about MopA. To gain a better understanding of MopA and its role in Mn(II) oxidation, the 238-kDa full-length protein and a 105-kDa truncated protein containing only the animal heme peroxidase domain were cloned and heterologously expressed in Escherichia coli. Despite having sequence similarity to a peroxidase, hydrogen peroxide did not stimulate activity, nor was activity significantly decreased in the presence of catalase. Both pyrroloquinoline quinone (PQQ) and hemin increased Mn-oxidizing activity, and calcium was required. The Km for Mn(II) of the full-length protein in cell extract was similar to that of the natively expressed protein, but the Km value for the truncated protein in cell extract was approximately 6-fold higher than that of the full-length protein, suggesting that the calcium binding domain may aid in binding Mn(II). Characterization of the heterologously expressed MopA has provided additional insight into the mechanism of bacterial Mn(II) oxidation, which will aid in understanding the role of MopA and Mn oxidation in bioremediation and biogeochemical cycling. PMID:25172859

  1. Purification and Characterization of the Manganese(II) Oxidizing Protein from Erythrobacter sp. SD-21

    NASA Astrophysics Data System (ADS)

    Nakama, K. R.; Lien, A.; Johnson, H. A.

    2013-12-01

    The manganese(II) oxidizing protein (Mop) found in the alpha-proteobacterium Erythrobacter sp. SD-21 catalyzes the formation of insoluble Mn(III/IV) oxides from soluble Mn(II). These Mn(III/IV) oxides formed are one of the strongest naturally occurring oxides, next to oxygen, and can be used to adsorb and oxidize toxic chemicals from the surrounding environment. Because of the beneficial use in the treatment of contaminated sources, the mechanism and biochemical properties of this novel enzyme are being studied. Due to low expression levels in the native host strain, purification of Mop has been problematic. To overcome this problem the gene encoding Mop, mopA, was cloned from the native host into a C-terminal histidine tag vector and expressed in Escherichia coli cells. Affinity chromatography under denaturing conditions have been applied in attempts to purify an active Mop. Western blots have confirmed that the protein is being expressed and is at the expected size of 250 kDa. Preliminary characterization on crude extract containing Mop has shown a Km and vmax value of 2453 uM and 0.025 uM min-1, respectively. Heme and pyrroloquinoline quinone can stimulate Mn(II) oxidizing activity, but hydrogen peroxide does not affect activity, despite the sequence similarity to animal heme peroxidase proteins. Research has been shown that calcium is essential for Mop activity. Purifying an active Mn(II) oxidizing protein will allow for a better understanding behind the enigmatic process of Mn(II) oxidation.

  2. Heterologous expression and characterization of the manganese-oxidizing protein from Erythrobacter sp. strain SD21.

    PubMed

    Nakama, Katherine; Medina, Michael; Lien, Ahn; Ruggieri, Jordan; Collins, Krystle; Johnson, Hope A

    2014-11-01

    The manganese (Mn)-oxidizing protein (MopA) from Erythrobacter sp. strain SD21 is part of a unique enzymatic family that is capable of oxidizing soluble Mn(II). This enzyme contains two domains, an animal heme peroxidase domain, which contains the catalytic site, followed by a C-terminal calcium binding domain. Different from the bacterial Mn-oxidizing multicopper oxidase enzymes, little is known about MopA. To gain a better understanding of MopA and its role in Mn(II) oxidation, the 238-kDa full-length protein and a 105-kDa truncated protein containing only the animal heme peroxidase domain were cloned and heterologously expressed in Escherichia coli. Despite having sequence similarity to a peroxidase, hydrogen peroxide did not stimulate activity, nor was activity significantly decreased in the presence of catalase. Both pyrroloquinoline quinone (PQQ) and hemin increased Mn-oxidizing activity, and calcium was required. The Km for Mn(II) of the full-length protein in cell extract was similar to that of the natively expressed protein, but the Km value for the truncated protein in cell extract was approximately 6-fold higher than that of the full-length protein, suggesting that the calcium binding domain may aid in binding Mn(II). Characterization of the heterologously expressed MopA has provided additional insight into the mechanism of bacterial Mn(II) oxidation, which will aid in understanding the role of MopA and Mn oxidation in bioremediation and biogeochemical cycling. PMID:25172859

  3. Synthèse et étude structrale de lyonsite-type (Na0,4,Li0,6)(Fe,Li2)(MoO4)3.

    PubMed

    Souilem, Amira; Zid, Mohamed Faouzi; Driss, Ahmed

    2015-06-01

    The new compound (Na0.4,Li0.6)(Fe,Li2)(MoO4)3 was synthesized by cooling from the melt. Its anionic framework is built up from two distinct MO6 octa-hedra, each containing disordered Li(+) and Fe(3+) ions in 0.6:0.4 and 0.7:0.3 ratios, and two MoO4 tetra-hedra, which link by vertex-sharing of their O atoms. These tetra-meric units are further linked by sharing edges between octa-hedra and by formation of M-O-Mo (M = Fe/Li) bridges, forming ribbons propagating in the [100] direction. The ribbons are cross-linked in both the b- and c-axis directions, giving rise to a three-dimensional framework having [100] tunnels in which the monovalent Na(+)/Li(+) cations (0.4:0.6 ratio) lie. Bond-valence calculations are consistent with the disorder model for the cations. The structure of the title compound, which is isotypic with Li3Fe(MoO4)3 and Li3Ga(MoO4)3, is compared briefly with those of LiFeMo2O8 and Li1.6Mn2.2(MoO4)3. PMID:26090130

  4. Microwave sintering of MoSi{sub 2}-Mo{sub 5}Si{sub 3} to promote a final nanometer-scale microstructure and suppressing of pesting phenomenon

    SciTech Connect

    Arreguin-Zavala, J. Turenne, S.; Martel, A.; Benaissa, A.

    2012-06-15

    This work shows an innovative sintering process for molybdenum disilicide (MoSi{sub 2}) and molybdenum silicide (Mo{sub 5}Si{sub 3}) in order to have a final nanometer-scale microstructure. Sintered MoSi{sub 2}-Mo{sub 5}Si{sub 3} was fabricated by microwave sintering. The final material showed a significant reduction of pesting phenomena for MoSi{sub 2}. The final microstructure is a mix of micrometer-scale MoSi{sub 2} and nanometer-scale Mo{sub 5}Si{sub 3} immersed in an amorphous SiO{sub 2} phase. This material was characterized by X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Thermal Gravimetric Analysis (TGA). - Highlights: Black-Right-Pointing-Pointer We sintered the MoSi{sub 2}-Mo{sub 5}Si{sub 3} by microwave and obtained high final density material. Black-Right-Pointing-Pointer We got a final nanostructured material. Black-Right-Pointing-Pointer We inhibited pesting phenomenon for MoSi{sub 2}.

  5. Phase diagram of Mg insertion into Chevrel phases, MgxMo6T8 (T = S, Se). 3. The crystal structure of triclinic Mg2Mo6Se8.

    PubMed

    Levi, E; Mitelman, A; Isnard, O; Brunelli, M; Aurbach, D

    2008-03-17

    This series of papers is devoted to unique cathode materials for Mg batteries, MgxMo6T8 (T = S, Se, x = 1 and 2) Chevrel phases (CPs). In this part, a combination of neutron and high-resolution synchrotron X-ray diffractions was used to study the crystal structure of Mg2Mo6Se8, which is triclinic at room temperature (space group P1, a = 6.868 A, b = 6.921 A, c = 6.880 A, alpha = 93.00 degrees , beta = 94.40 degrees , gamma = 96.22 degrees ). In contrast to other members of the MgxMo6T8 family, this compound does not follow the classic scheme of successive cation insertion into so-called inner and outer sites: Both the Mg(2+) ions per formula are located in the tetrahedral sites of the outer ring. This surprising cation location, predicted previously for Mg-containing CPs by ab initio calculations, provides the uniform distribution of the cation charge in the triclinic structure, which is similar to that of rhombohedral CPs. A mapping of the cation sites was widely used to demonstrate the variety of cation arrangement in CPs and the factors affecting this arrangement, as well as to clarify the origin of the exceptionally high mobility of the Mg(2+) ions in Mg2Mo6Se8. PMID:18290612

  6. Characterization of solid-phase welds between Ti-6Al-2Sn-4Zr-2Mo-0. 01Si and Ti-13. 5A1-21. 5Nb titanium aluminide

    SciTech Connect

    Baeslack, W.A. III; Juhas, M.; Fraser, H.L. ); Broderick, T.F. . Materials Directorate)

    1994-12-01

    Dissimilar-alloy welds have been produced between Ti-6Al-2Sn-4Zr-2Mo-0.1Si (wt.%) and Ti-13.5Al-21.5Nb (wt.%) titanium aluminide using three different solid-phase welding processes that create significantly different thermo-mechanical conditions at the weld interface. Exposure to supertransus temperatures, appreciable deformation and rapid cooling of the weld interface region during linear-friction welding promote dynamic recrystallization of beta grains and beta decomposition to fine martensitic products. In contrast, diffusion welding at temperatures below the base metal beta transus temperatures and at relatively low pressures minimizes deformation and microstructural variations in the weld interface region relative to the unaffected base metal. During capacitor-discharge resistance spot welding, extremely rapid heating of the weld interface region to near-solidus temperatures, and subsequent rapid cooling, result in the formation of a metastable, ordered-beta microstructure in the Ti-13.5ASl-21.5Nb and fine alpha-prime martensite in the Ti-6Al-2Sn-4Zr-2Mo-0.1Si.

  7. Assessment of the optimum degree of Sr{sub 3}Fe{sub 2}MoO{sub 9} electron-doping through oxygen removal: An X-ray powder diffraction and {sup 57}Fe Moessbauer spectroscopy study

    SciTech Connect

    Lopez, Carlos A.; Viola, Maria del C.; Pedregosa, Jose C.; Mercader, Roberto C.

    2010-10-15

    We describe the preparation and structural characterization by X-ray powder diffraction (XRPD) and Moessbauer spectroscopy of three electron-doped perovskites Sr{sub 3}Fe{sub 2}MoO{sub 9-{delta}} with Fe/Mo = 2 obtained from Sr{sub 3}Fe{sub 2}MoO{sub 9}. The compounds were synthesized by topotactic reduction with H{sub 2}/N{sub 2} (5/95) at 600, 700 and 800 {sup o}C. Above 800 {sup o}C the Fe/Mo ratio changes from Fe/Mo = 2-1 < Fe/Mo < 2. The structural refinements of the XRPD data for the reduced perovskites were carried out by the Rietveld profile analysis method. The crystal structure of these phases is cubic, space group Fm3-bar m, with cationic disorder at the two different B sites that can be populated in variable proportions by the Fe atoms. The Moessbauer spectra allowed determining the evolution of the different species formed after the treatments at different temperatures and confirm that Fe ions in the samples reduced at 600, 700 and 800 {sup o}C are only in the high-spin Fe{sup 3+} electronic state.

  8. Cationic Intermixing and Reactivity at the La2 Mo2 O9 /La0.8 Sr0.2 MnO3-δ Solid Oxide Fuel Cell Electrolyte-Cathode Interface.

    PubMed

    Ravella, Uday K; Liu, Jingjing; Corbel, Gwenaël; Skinner, Stephen J; Lacorre, Philippe

    2016-08-23

    Among standard high-temperature cathode materials for solid oxide fuel cells, La0.8 Sr0.2 MnO3-δ (LSM) displays the least reactivity with the oxide-ion conductor La2 Mo2 O9 (LMO), yet a reaction is observed at high processing temperatures, identified by using XRD and focused ion beam secondary-ion mass spectrometry (FIB-SIMS) after annealing at 1050 and 1150 °C. Additionally, Sr and Mn solutions were deposited and annealed on LMO pellets, as well as a Mo solution on a LSM pellet. From these studies several reaction products were identified by using XRD and located by using FIB-SIMS on the surface of pelletised samples. We used depth profiling to show that the reactivity extended up to ∼10 μm from the surface region. If Sr was present, a SrMoO4 -type scheelite phase was always observed as a reaction product, and if Mn was present, LaMnO3+δ single crystals were observed on the surface of the LMO pellets. Additional phases such as La2 MoO6 and La6 MoO12 were also detected depending on the configuration and annealing temperature. Reaction mechanisms and detailed reaction formulae are proposed to explain these observations. The strongest driving force for cationic diffusion appears to originate from Mo(6+) and Mn(3+) cations, rather than from Sr(2+) . PMID:27478975

  9. Synthèse et étude structrale de lyonsite-type (Na0,4,Li0,6)(Fe,Li2)(MoO4)3

    PubMed Central

    Souilem, Amira; Zid, Mohamed Faouzi; Driss, Ahmed

    2015-01-01

    The new compound (Na0.4,Li0.6)(Fe,Li2)(MoO4)3 was synthesized by cooling from the melt. Its anionic framework is built up from two distinct MO6 octa­hedra, each containing disordered Li+ and Fe3+ ions in 0.6:0.4 and 0.7:0.3 ratios, and two MoO4 tetra­hedra, which link by vertex-sharing of their O atoms. These tetra­meric units are further linked by sharing edges between octa­hedra and by formation of M—O—Mo (M = Fe/Li) bridges, forming ribbons propagating in the [100] direction. The ribbons are cross-linked in both the b- and c-axis directions, giving rise to a three-dimensional framework having [100] tunnels in which the monovalent Na+/Li+ cations (0.4:0.6 ratio) lie. Bond-valence calculations are consistent with the disorder model for the cations. The structure of the title compound, which is isotypic with Li3Fe(MoO4)3 and Li3Ga(MoO4)3, is compared briefly with those of LiFeMo2O8 and Li1.6Mn2.2(MoO4)3. PMID:26090130

  10. Microwave-assisted ionic-liquid-based synthesis of highly crystalline CaMoO4:RE3+ (RE = Tb, Sm, Eu) and Y2Mo4O15:Eu3+ nanoparticles

    NASA Astrophysics Data System (ADS)

    Kuzmanoski, Ana; Pankratov, Vladimir; Feldmann, Claus

    2015-03-01

    Fluorescent CaMoO4:RE3+ (RE = Tb, Sm, Eu) nanoparticles, 50-70 nm in diameter, were prepared via a microwave-assisted synthesis in ionic liquids. Herein, the ionic liquid allows heating to high temperatures in the liquid phase (200 °C), which guarantees for an optimal crystallization of the nanoparticles. All nanoparticles were indeed readily crystalline without the need of any additional powder sintering. Especially, CaMoO4:Tb and CaMoO4:Eu exhibit high quantum yields of 52% and 82% under UV-excitation (300-320 nm). All compounds were characterized by electron microscopy (SEM), dynamic light scattering (DLS), infrared spectroscopy (FT-IR), energy-dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and fluorescence spectroscopy (FL). In order to shift the excitation to even higher wavelengths, Y2Mo4O15:Eu was firstly realized as a nanomaterial, again, using the microwave-assisted synthesis in ionic liquids. Y2Mo4O15:Eu exhibits a particle size of 25-30 nm, and shows a high quantum yield of 67%, too. As this nanomaterial can be excited up to 400 nm, it represents one of the first efficient red-emitting, Eu3+-doped nanomaterials for near-UV excitation (>350 nm) with a simple, low-cost UV-LED. This can be relevant for all kinds of thin-film applications as well as for optical imaging.

  11. Origin of periodic domain structure in Er{sup 3+}-doped beta'-(Sm,Gd){sub 2}(MoO{sub 4}){sub 3} crystal lines patterned by laser irradiations in glasses

    SciTech Connect

    Suzuki, Futoshi; Honma, Tsuyoshi; Komatsu, Takayuki

    2010-04-15

    Er{sup 3+}-doped beta'-(Sm,Gd){sub 2}(MoO{sub 4}){sub 3} crystal lines are patterned on the surface of Er{sub 2}O{sub 3}-Gd{sub 2}O{sub 3}-Sm{sub 2}O{sub 3}-MoO{sub 3}-B{sub 2}O{sub 3} glasses by continuous-wave Yb:YVO{sub 4} laser irradiations (wavelength: 1080 nm, power: 1.3 W, scanning speeds: 5 {mu}m/s), and the origin of the periodicity of self-organized domain structures with high and low refractive index regions in crystal lines is examined from polarized optical microscope (POM) observations, micro-Raman scattering spectrum, and photoluminescence spectrum measurements. It is found that the periodicity of domain structures changes largely depending on Er{sub 2}O{sub 3} content, i.e., the length of high (bright color in POM observations) and low (dark color) refractive index regions increases with increasing Er{sub 2}O{sub 3} content and homogeneous crystal lines with no periodic domain structures are patterned in Er{sub 2}O{sub 3}-Sm{sub 2}O{sub 3}-MoO{sub 3}-B{sub 2}O{sub 3} glass with no Gd{sub 2}O{sub 3}. Considering that the degree of ferroelasticities in beta'-(Sm,Gd){sub 2}(MoO{sub 4}){sub 3} crystals decreases due to the incorporation of Er{sup 3+} ions, it is demonstrated that the origin of periodic domain structures in laser-patterned lines is due to spontaneous strains in ferroelastic beta'-(Sm,Gd){sub 2}(MoO{sub 4}){sub 3} crystals. - Graphical abstract: This figure shows the polarized optical photographs (top view) for the lines patterned by laser irradiations with the power of P=1.3 W and the scanning speed of S=5 {mu}m/s in xEr{sub 2}O{sub 3}-(18.25-x)Gd{sub 2}O{sub 3}-3Sm{sub 2}O{sub 3}-63.75MoO{sub 3}-15B{sub 2}O{sub 3} (mol%) glasses. This figure indicates that the periodicity of domain structures in beta'-(Sm,Gd){sub 2}(MoO{sub 4}){sub 3} crystal lines, i.e., the lengths of bright (high refractive index) and dark (low refractive index) color regions, changes depending on the amount of Er{sub 2}O{sub 3} addition. It is demonstrated that the

  12. Identification of endogenous surrogate ligands for human P2Y{sub 12} receptors by in silico and in vitro methods

    SciTech Connect

    Nonaka, Yosuke; Hiramoto, Takeshi; Fujita, Norihisa . E-mail: nori@is.ritsumei.ac.jp

    2005-11-11

    Endogenous ligands acting on a human P2Y{sub 12} receptor, one of the G-protein coupled receptors, were searched by in silico screening against our own database, which contains more than 500 animal metabolites. The in silico screening using the docking software AutoDock resulted in selection of cysteinylleukotrienes (CysLTs) and 5-phosphoribosyl 1-pyrophosphate (PRPP), with high free energy changes, in addition to the known P2Y{sub 12} ligands such as 2MeSADP and ADP. These candidates were subjected to an in vitro Ca{sup 2+} assay using the CHO cells stably expressing P2Y{sub 12}-G{sub 16}{alpha} fusion proteins. We found that CysLTE4 and PRPP acted on the P2Y{sub 12} receptor as agonists with the EC{sub 50} values of 1.3 and 7.8 nM, respectively. Furthermore, we analyzed the phylogenetic relationship of the P2Y, P2Y-like, and CysLT receptors based on sequence alignment followed by evolutionary analyses. The analyses showed that the P2Y{sub 12}, P2Y{sub 13}, P2Y{sub 14}, GPR87, CysLT-1, and CysLT-2 receptors formed a P2Y-related receptor subfamily with common sequence motifs in the transmembrane regions.

  13. Identification of a New Marine Bacterial Strain SD8 and Optimization of Its Culture Conditions for Producing Alkaline Protease

    PubMed Central

    Cui, Hongxia; Yang, Muyang; Wang, Liping; Xian, Cory J.

    2015-01-01

    While much attention has been given to marine microorganisms for production of enzymes, which in general are relatively more stable and active compared to those from plants and animals, studies on alkaline protease production from marine microorganisms have been very limited. In the present study, the alkaline protease producing marine bacterial strain SD8 isolated from sea muds in the Geziwo Qinhuangdao sea area of China was characterized and its optimal culture conditions were investigated. Strain SD8 was initially classified to belong to genus Pseudomonas by morphological, physiological and biochemical characterizations, and then through 16S rDNA sequence it was identified to be likely Pseudomonas hibiscicola. In addition, the culture mediums, carbon sources and culture conditions of strain SD8 were optimized for maximum production of alkaline protease. Optimum enzyme production (236U/mL when cultured bacteria being at 0.75 mg dry weight/mL fermentation broth) was obtained when the isolate at a 3% inoculum size was grown in LB medium at 20 mL medium/100mL Erlenmeyer flask for 48h culture at 30°C with an initial of pH 7.5. This was the first report of strain Pseudomonas hibiscicola secreting alkaline protease, and the data for its optimal cultural conditions for alkaline protease production has laid a foundation for future exploration for the potential use of SD8 strain for alkaline protease production. PMID:26716833

  14. 76 FR 58241 - Designation for the Aberdeen, SD; Decatur, IL; Hastings, NE; Fulton, IL; the State of Missouri...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-20

    ..., Federal Register (76 FR 15937), GIPSA requested applications for designation to provide official services... Grain Inspection, Packers and Stockyards Administration Designation for the Aberdeen, SD; Decatur, IL; Hastings, NE; Fulton, IL; the State of Missouri, and the State of South Carolina Areas AGENCY:...

  15. Identification of a New Marine Bacterial Strain SD8 and Optimization of Its Culture Conditions for Producing Alkaline Protease.

    PubMed

    Cui, Hongxia; Yang, Muyang; Wang, Liping; Xian, Cory J

    2015-01-01

    While much attention has been given to marine microorganisms for production of enzymes, which in general are relatively more stable and active compared to those from plants and animals, studies on alkaline protease production from marine microorganisms have been very limited. In the present study, the alkaline protease producing marine bacterial strain SD8 isolated from sea muds in the Geziwo Qinhuangdao sea area of China was characterized and its optimal culture conditions were investigated. Strain SD8 was initially classified to belong to genus Pseudomonas by morphological, physiological and biochemical characterizations, and then through 16S rDNA sequence it was identified to be likely Pseudomonas hibiscicola. In addition, the culture mediums, carbon sources and culture conditions of strain SD8 were optimized for maximum production of alkaline protease. Optimum enzyme production (236U/mL when cultured bacteria being at 0.75 mg dry weight/mL fermentation broth) was obtained when the isolate at a 3% inoculum size was grown in LB medium at 20 mL medium/100mL Erlenmeyer flask for 48h culture at 30°C with an initial of pH 7.5. This was the first report of strain Pseudomonas hibiscicola secreting alkaline protease, and the data for its optimal cultural conditions for alkaline protease production has laid a foundation for future exploration for the potential use of SD8 strain for alkaline protease production. PMID:26716833

  16. Application of chirally-deuterated (S)-D-(6-2H1)glucose to conformational studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deuterated sugars are widely used to elucidate mechanisms of biosynthesis and of chemical reactions, and to confirm assignments of complex NMR or mass spectra. To date, however, there are few reported syntheses for regio and stereospecifically deuterated pyranoses. Chirally-deuterated (S)-D-(6-**2...

  17. Nocardiopsis sp. SD5: a potent feather degrading rare actinobacterium isolated from feather waste in Tamil Nadu, India.

    PubMed

    Saha, Subhasish; Dhanasekaran, D; Shanmugapriya, S; Latha, S

    2013-07-01

    Feather waste, generated in large quantities as a byproduct of commercial poultry processing, is nearly pure keratin protein, and keratin in its native state is not degradable by common proteolytic enzymes. The aim of the study was to find a potent feather degrading actinobacteria from feather waste soil. Out of 91 actinobacterial isolates recorded from feather waste soil in Tiruchirappalli and Nammakkal District, Tamil Nadu, India, isolate SD5 was selected for characterization because it exhibited significant keratinolytic activity. On the basis of the phenotypic, biochemical characterization and 16S rRNA gene-sequencing studies, the isolate was identified as Nocardiopsis sp. SD5. Protease and keratinase activity of Nocardiopsis sp. SD5 were analyzed. The enzyme was more stable over the neutral pH and the temperature of 40 °C. The optimum temperature and pH for both proteolytic and keratinolytic activity was determined at 50 °C and pH 9, respectively. Enzyme inhibitors, detergents and chelator declined the enzyme activity with increasing concentration. Nondenaturing polyacrylamide gel electrophoresis and zymogram elucidated the presence of 30 and 60 kDa protease enzymes. These findings indicated that thermo alkaliphilic feather degrading strain Nocardiopsis sp. SD5 could be used to control the feather waste pollution and to convert keratin rich feather waste into useful feedstock for poultry industry. PMID:23864545

  18. Nocardiopsis sp. SD5: A potent feather degrading rare actinobacterium isolated from feather waste in Tamil Nadu, India.

    PubMed

    Saha, Subhasish; Dhanasekaran, D; Shanmugapriya, S; Latha, S

    2012-08-23

    Feather waste, generated in large quantities as a byproduct of commercial poultry processing, is nearly pure keratin protein, and keratin in its native state is not degradable by common proteolytic enzymes. The aim of the study was to find a potent feather degrading actinobacteria from feather waste soil. Out of 91 actinobacterial isolates recorded from feather waste soil in Tiruchirappalli and Nammakkal District, Tamil Nadu, India, isolate SD5 was selected for characterization because it exhibited significant keratinolytic activity. On the basis of the phenotypic, biochemical characterization and 16S rRNA gene-sequencing studies, the isolate was identified as Nocardiopsis sp. SD5. Protease and keratinase activity of Nocardiopsis sp. SD5 were analyzed. The enzyme was more stable over the neutral pH and the temperature of 40 °C. The optimum temperature and pH for both proteolytic and keratinolytic activity was determined at 50 °C and pH 9, respectively. Enzyme inhibitors, detergents and chelator declined the enzyme activity with increasing concentration. Non denaturing poly acrylamide gel electrophoresis and zymogram elucidated the presence of 30 kda and 60 kda protease enzymes. These findings indicated that thermo alkaliphilic feather degrading strain Nocardiopsis sp. SD5 could be used to control the feather waste pollution and to convert keratin rich feather waste into useful feedstock for poultry industry. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim). PMID:22914902

  19. HS 2333+3927: A new sdB+dM binary with a large reflection effect

    NASA Astrophysics Data System (ADS)

    Heber, U.; Drechsel, H.; Østensen, R.; Karl, C.; Napiwotzki, R.; Altmann, M.; Cordes, O.; Solheim, J.-E.; Voss, B.; Koester, D.; Folkes, S.

    2004-06-01

    We have discovered periodic light variations (P = 0.1718023 d) in the sdB star HS 2333+3927 in the BVR bands with amplitudes of 0.21, 0.28 and 0.33 mag, respectively. Sinusoidal radial velocity variations at the same period were detected with a semi-amplitude of K1 = 89.6 km s-1, indicating that it is binary system and that the light variations are caused by the reflection effect with no eclipses. A mass function of f(m)= 0.0128 M⊙ has been determined. The analysis of the light curve did not yield a unique solution, mainly because the albedo of the secondary is poorly constrained. Two solutions of equal quality with a high (A2= 1.0) and a low (A2= 0.39) albedo were considered further. Variability of the Balmer line profiles, most notably for Hα, was discovered, probably also caused by the reflection effect. A spectroscopic analysis results in Teff = 36 500 K, log g = 5.70, and log (nHe/nH) = -2.15. These characteristics are typical for sdB stars. Mass-radius relations are derived from the results of the analysis of light and radial-velocity curves. Comparison with the observed mass-radius relation of the sdB star and with that of lower main sequence stars for the companion allows us to discard the high albedo solution, because the resulting mass of the primary and the radius of the secondary would be unreasonably low. From a discussion of evolutionary models we constrain the plausible mass of the sdB to the range between 0.29 M⊙ and 0.47 M⊙. Accordingly, the mass of the secondary is between 0.24 M⊙ and 0.32 M⊙, indicating a spectral type of M3 to M4. HS 2333+3927 is only the sixth sdB+dM system discovered so far. An improved measurement of the gravity and the projected rotational velocity of the sdB star is required to further constrain the masses and to identify the evolutionary state of the sdB star uniquely. Based on observations obtained at the German-Spanish Astronomical Center (DSAZ) at Calar Alto, the Nordic Optical Telescope (NOT) and the Jacobus

  20. A CHANDRA OBSERVATION OF THE NEARBY SCULPTOR GROUP Sd GALAXY NGC 7793

    SciTech Connect

    Pannuti, Thomas G.; Staggs, Wayne D.; Schlegel, Eric M.; Filipovic, Miroslav D.; Payne, Jeffrey L.; Petre, Robert

    2011-07-15

    We conducted a Chandra ACIS observation of the nearby Sculptor Group Sd galaxy NGC 7793 as part of a multiwavelength study of supernova remnants (SNRs) in nearby galaxies. At the assumed distance to NGC 7793 of 3.91 Mpc, the limiting unabsorbed luminosity of the detected discrete X-ray sources is L{sub X} (0.2-10.0 keV) {approx}3x10{sup 36} erg s{sup -1}. A total of 22 discrete sources were detected at the {approx}3{sigma} level or greater including one ultraluminous X-ray source (ULX). Based on multiwavelength comparisons, we identify X-ray sources coincident with one SNR, the candidate microquasar N7793-S26, one H II region, and two foreground Galactic stars. We also find that the X-ray counterpart to the candidate radio SNR R3 is time variable in its X-ray emission: we therefore rule out the possibility that this source is a single SNR. A marked asymmetry is seen in the distribution of the discrete sources with the majority lying in the eastern half of this galaxy. All of the sources were analyzed using quantiles to estimate spectral properties and spectra of the four brightest sources (including the ULX) were extracted and analyzed. We searched for time variability in the X-ray emission of the detected discrete sources using our measured fluxes along with fluxes measured from prior Einstein and Roentgensatellit observations. From this study, three discrete X-ray sources are established to be significantly variable. A spectral analysis of the galaxy's diffuse emission is characterized by a temperature of kT = 0.19-0.25 keV. The luminosity function of the discrete sources shows a slope with an absolute value of {Gamma} = -0.65 {+-} 0.11 if we exclude the ULX. If the ULX is included, the luminosity function has a long tail to high L{sub X} with a poor-fitting slope of {Gamma} = -0.62 {+-} 0.2. The ULX-less slope is comparable to the slopes measured for the distributions of NGC 6946 and NGC 2403 but much shallower than the slopes measured for the distributions of

  1. High Brightness Picture Technology In SD-P40 Projection TV

    NASA Astrophysics Data System (ADS)

    Hasegawa, Shinichi

    1987-04-01

    Pioneer Electric Company has developed a new generation 40-inch rear projection SD-P40 television, a revolutionary, new television that realizes white peak brightness of 300 ft-I and high contrast. The combination of high brightness and high contrast is made possible primarily by newly developed optical-coupling technology that utilizes newly developed concepts. This new optical coupling technology cools the CRT quite efficiently, making it possible to greatly increase the CRT power input to obtain high brightness and at the same time provides greater reliability than direct view televisions. The new optical-coupling technology also makes it possible to almost completely eliminate the reflectance at the boundaries between the CRT and the lens and air, which gives much higher contrast than previous televisions. Not only does this optical-coupling technology provide high performance, in addition since the liquid coolant it employs functions as a liquid lens, the coupling lens can be designed to a uniform thinness and a small aperture. This greatly reduces the cost of the lens. Our newly developed optical-coupling technology is the ultimate form of cooling for the CRT tubes of projection televisions and coupling with the lens and will become the mainstream technology in the future. It is forecast that other manufacturers will also adopt this type of technology. The optical lens section, which is the heart of a projection television, is a hybrid structure with three aspherical plastic lenses and one glass spherical lens. It has higher performance image formation and greater temperature stability than previous televisions. The plastic lenses are all finished with multi-coating to hold down light loss and maximize transparency. This con-tributes greatly to increasing the brightness for a projection television. Previous 3-tube type projection televisions were bothered by low color uniformity, color shift, and low color rela-tive illumination. This model uses three bends

  2. An Rgd Sequence in the P2y2 Receptor Interacts with αVβ3 Integrins and Is Required for Go-Mediated Signal Transduction

    PubMed Central

    Erb, Laurie; Liu, Jun; Ockerhausen, Jonathan; Kong, Qiongman; Garrad, Richard C.; Griffin, Korey; Neal, Chris; Krugh, Brent; Santiago-Pérez, Laura I.; González, Fernando A.; Gresham, Hattie D.; Turner, John T.; Weisman, Gary A.

    2001-01-01

    The P2Y2 nucleotide receptor (P2Y2R) contains the integrin-binding domain arginine-glycine-aspartic acid (RGD) in its first extracellular loop, raising the possibility that this G protein–coupled receptor interacts directly with an integrin. Binding of a peptide corresponding to the first extracellular loop of the P2Y2R to K562 erythroleukemia cells was inhibited by antibodies against αVβ3/β5 integrins and the integrin-associated thrombospondin receptor, CD47. Immunofluorescence of cells transfected with epitope-tagged P2Y2Rs indicated that αV integrins colocalized 10-fold better with the wild-type P2Y2R than with a mutant P2Y2R in which the RGD sequence was replaced with RGE. Compared with the wild-type P2Y2R, the RGE mutant required 1,000-fold higher agonist concentrations to phosphorylate focal adhesion kinase, activate extracellular signal–regulated kinases, and initiate the PLC-dependent mobilization of intracellular Ca2+. Furthermore, an anti-αV integrin antibody partially inhibited these signaling events mediated by the wild-type P2Y2R. Pertussis toxin, an inhibitor of Gi/o proteins, partially inhibited Ca2+ mobilization mediated by the wild-type P2Y2R, but not by the RGE mutant, suggesting that the RGD sequence is required for P2Y2R-mediated activation of Go, but not Gq. Since CD47 has been shown to associate directly with Gi/o family proteins, these results suggest that interactions between P2Y2Rs, integrins, and CD47 may be important for coupling the P2Y2R to Go. PMID:11331301

  3. The structural evolution of a P2Y-like G-protein-coupled receptor.

    PubMed

    Schulz, Angela; Schöneberg, Torsten

    2003-09-12

    Based on the now available crystallographic data of the G-protein-coupled receptor (GPCR) prototype rhodopsin, many studies have been undertaken to build or verify models of other GPCRs. Here, we mined evolution as an additional source of structural information that may guide GPCR model generation as well as mutagenesis studies. The sequence information of 61 cloned orthologs of a P2Y-like receptor (GPR34) enabled us to identify motifs and residues that are important for maintaining the receptor function. The sequence data were compared with available sequences of 77 rhodopsin orthologs. Under a negative selection mode, only 17% of amino acid residues were preserved during 450 million years of GPR34 evolution. On the contrary, in rhodopsin evolution approximately 43% residues were absolutely conserved between fish and mammals. Despite major differences in their structural conservation, a comparison of structural data suggests that the global arrangement of the transmembrane core of GPR34 orthologs is similar to rhodopsin. The evolutionary approach was further applied to functionally analyze the relevance of common scaffold residues and motifs found in most of the rhodopsin-like GPCRs. Our analysis indicates that, in contrast to other GPCRs, maintaining the unique function of rhodopsin requires a more stringent network of relevant intramolecular constrains. PMID:12835326

  4. The P2Y13 receptor regulates phosphate metabolism and FGF-23 secretion with effects on skeletal development.

    PubMed

    Wang, Ning; Robaye, Bernard; Gossiel, Fatima; Boeynaems, Jean-Marie; Gartland, Alison

    2014-05-01

    Purinergic signaling mediates many cellular processes, including embryonic development and regulation of endocrine signaling. The ADP P2Y13 receptor is known to regulate bone and stem cells activities, although relatively little is known about its role in bone development. In this study we demonstrate, using contemporary techniques, that deletion of the P2Y13 receptor results in an age-dependent skeletal phenotype that is governed by changes in phosphate metabolism and hormone levels. Neonatal and postnatal (2 wk) P2Y13 receptor-knockout (KO) mice were indistinguishable from their wild-type (WT) littermate controls. A clear bone phenotype was observed in young (4-wk-old) KO mice compared WT controls, with 14% more trabecular bone, 35% more osteoblasts, 73% fewer osteoclasts, and a 17% thicker growth plate. Mature (>10 wk of age) KO mice showed the opposite bone phenotype, with 14% less trabecular bone, 22% fewer osteoblasts, and 10% thinner growth plate. This age-dependent phenotype correlated with serum fibroblast growth factor-23 (FGF-23) and phosphorus levels that were 65 and 16% higher, respectively, in young KO mice but remained unchanged in mature mice. These findings provide novel insights for the role of the P2Y13 receptor in skeletal development via coordination with hormonal regulators of phosphate homeostasis. PMID:24487286

  5. State of affairs: Design and structure-activity relationships of reversible P2Y12 receptor antagonists.

    PubMed

    Zetterberg, Fredrik; Svensson, Peder

    2016-06-15

    Myocardial infarction and stroke are the most common causes of mortality and morbidity in the developed world. Therefore the search for antiplatelet therapy has been in focus for the last decades, in particular the search for new P2Y12R antagonists. The first P2Y12R drug developed, clopidogrel, is a major success but there is still room for improvement with respect to bleeding profile and non-responders. These liabilities could be due to the fact that clopidogrel is a pro-drug and upon activation binds covalently to the receptor. Therefore a lot of effort has gone into identifying reversible inhibitors. One recent example is ticagrelor, which in clinical studies have been shown to be safer and even reduce rate of death from vascular events as compared head to head with clopidogrel. We here review the medicinal chemistry strategies used in the design of new reversible P2Y12R antagonists. In addition, we also present structure based design studies based on the recently published agonist and antagonist X-ray structures of P2Y12R. PMID:27133596

  6. Chemical analyses of pore water from boreholes USW SD-6 and USW WT-24, Yucca Mountain, Nevada

    USGS Publications Warehouse

    Yang, I.C.; Peterman, Z.E.; Scofield, K.M.

    2003-01-01

    Analyses of pore water extracted from cores of boreholes USW SD-6 in the central part and USW WT-24 in the northern part of Yucca Mountain, Nevada, show significant vertical and lateral variations in dissolved-ion concentrations. Analyses of samples of only a few milliliters of pore water extracted by uniaxial or triaxial compression and by ultracentrifugation methods from adjacent core samples are generally in agreement, within the analytical error of 10% to 15%. However, the values of silica for water obtained by ultracentrifugation are consistently lower than values for water obtained by compression. The larger concentrations probably are due to localized pressure solution of silicate minerals during compression. The shallower water from core in borehole USW SD-6 was extracted from nonwelded units collectively referred to as the Paintbrush Tuff nonwelded (PTn). The deeper water was from core in both boreholes USW SD-6 and USW WT-24 in the nonwelded units referred to as the Calico Hills nonwelded (CHn). Significant differences in mean dissolved-ion concentrations in pore water between the PTn and CHn are (1) decreases in Ca, Mg, SO4, and NO3 and (2) increases in HCO3 and (Na+K)/(Ca+Mg) ratios. The decrease in NO3 and the increase in HCO3 could be the result of denitrification through the oxidation of organic matter. The decrease in Ca and associated increase in (Na+K)/(Ca+Mg) is the result of ion exchange with zeolites in the CHn in borehole USW WT-24. This effect is not nearly as pronounced in borehole USW SD-6, probably reflecting a smaller amount of zeolitization of the CHn in USW SD-6. Geochemical calculations using the PHREEQC code indicate that the pore water from both boreholes USW SD-6 and USW WT-24 is uniformly undersaturated in anhydrite, gypsum, and amorphous silica, but supersaturated in quartz and chalcedony. The saturation of calcite, aragonite, sepiolite, and dolomite is more variable from sample to sample. ?? 2002 Elsevier Science B.V. All rights

  7. Southern galaxies. VIII - Surface photometry of the SD spiral NGC 7793

    NASA Astrophysics Data System (ADS)

    de Vaucouleurs, G.; Davoust, E.

    1980-08-01

    Detailed surface photometry in blue light of the SA(s)d galaxy NGC 7793, the faintest of the five major members of the Sculptor group, is obtained from photoelectrically calibrated Mount Stromlo and McDonald photographs. The luminosity distribution is dominated by an exponential disk of effective radius αe = 2'.11 = 1.92 kpc contributing 98.6% of the total luminosity BT = 9.51 ± 0.06. The corrected face-on magnitude BT0 = 9.13 corresponds to MT0 = -18.35 at the revised distance Δ = 3.1 Mpc (Appendix C). The spheroidal component visible only in the vicinity of the nucleus can be represented by an r1/4 law of effective radius rIe = 6".0 = 91 pc and total magnitude BTI = 14.13 or 1.4% of the total luminosity of the galaxy. The position angle of the major axis is 97°, the mean axis ratio is q = b/a = 0.61, and the inclination = 53°. The concentration indices C21 = 1.68 and C32 = 1.48 are consistent with the Sd classification. The integrated colors from UBV aperture photometry are essentially constant at = 0.56 ± 0.02, = -0.07 ± 0.02, the corrected face-on colors are (B - V)T0 = 0.46, (U - B)T0 = -0.15 in close agreement with the colors of M33 and the mean values for type Scd. A decomposition of the disk into an underlying old component and a young arm component shows that 65.570 of the total luminosity comes from the old component which has a corrected central luminosity μcα(0) = 21.06 and an effective radius re = 1'.76 = 1.60 kpc. The neutral H I mass MH = 0.67 × 109 Msun corresponds to a hydrogen-luminosity ratio MH/LB = 0.14 which is less than half the average for the morphological type and luminosity class of NGC 7793. The large number of H ii regions and the strength of the Hα emission in the disk suggest that a large fraction of the hydrogen is ionized. The integrated magnitude of the brightest superassociation (Hodge Nr 20) B, = 16.0 ± 0.1 is derived in Appendix A. The effect of resolution on the apparent peak brightness is illustrated in Appendix B

  8. P2Y1 Receptor Activation of the TRPV4 Ion Channel Enhances Purinergic Signaling in Satellite Glial Cells.

    PubMed

    Rajasekhar, Pradeep; Poole, Daniel P; Liedtke, Wolfgang; Bunnett, Nigel W; Veldhuis, Nicholas A

    2015-11-27

    Transient receptor potential (TRP) ion channels of peripheral sensory pathways are important mediators of pain, itch, and neurogenic inflammation. They are expressed by primary sensory neurons and by glial cells in the central nervous system, but their expression and function in satellite glial cells (SGCs) of sensory ganglia have not been explored. SGCs tightly ensheath neurons of sensory ganglia and can regulate neuronal excitability in pain and inflammatory states. Using a modified dissociation protocol, we isolated neurons with attached SGCs from dorsal root ganglia of mice. SGCs, which were identified by expression of immunoreactive Kir4.1 and glutamine synthetase, were closely associated with neurons, identified using the pan-neuronal marker NeuN. A subpopulation of SGCs expressed immunoreactive TRP vanilloid 4 (TRPV4) and responded to the TRPV4-selective agonist GSK1016790A by an influx of Ca(2+) ions. SGCs did not express functional TRPV1, TRPV3, or TRP ankyrin 1 channels. Responses to GSK1016790A were abolished by the TRPV4 antagonist HC067047 and were absent in SGCs from Trpv4(-/-) mice. The P2Y1-selective agonist 2-methylthio-ADP increased [Ca(2+)]i in SGCs, and responses were prevented by the P2Y1-selective antagonist MRS2500. P2Y1 receptor-mediated responses were enhanced in TRPV4-expressing SGCs and HEK293 cells, suggesting that P2Y1 couples to and activates TRPV4. PKC inhibitors prevented P2Y1 receptor activation of TRPV4. Our results provide the first evidence for expression of TRPV4 in SGCs and demonstrate that TRPV4 is a purinergic receptor-operated channel in SGCs of sensory ganglia. PMID:26475857

  9. Deletion of GOLGA2P3Y but not GOLGA2P2Y is a risk factor for oligozoospermia.

    PubMed

    Sen, Sanjukta; Agarwal, Rupesh; Ambulkar, Prafulla; Hinduja, Indira; Zaveri, Kusum; Gokral, Jyotsna; Pal, Asoke; Modi, Deepak

    2016-02-01

    The AZFc locus on the human Y chromosome harbours several multicopy genes, some of which are required for spermatogenesis. It is believed that deletion of one or more copies of these genes is a cause of infertility in some men. GOLGA2LY is one of the genes in the AZFc locus and it exists in two copies, GOLGA2P2Y and GOLGA2P3Y. The involvement of GOLGA2LY gene copy deletions in male infertility, however, is unknown. This study aimed to investigate the association of deletions of GOLGA2P2Y and GOLGA2P3Y gene copies with male infertility and with sperm concentration and motility. The frequency of GOLGA2P3Y deletion was significantly higher in oligozoospermic men compared with normozoospermic men (7.7% versus 1.2%; P = 0.0001), whereas the frequency of GOLGA2P2Y deletion was comparable between oligozoospermic and normozoospermic men (10.3% versus 11.3%). The deletion of GOLGA2P3Y but not GOLGA2P2Y was significantly higher (P = 0.03) in men with gr/gr rearrangements, indicating that GOLGA2P3Y deletions increase the susceptibility of men with gr/gr rearrangements to oligozoospermia. Furthermore, men with GOLGA2P3Y deletion had reduced sperm concentration and motility compared with men without deletion or with deletion of GOLGA2P2Y. These findings indicate GOLGA2P3Y gene copy may be candidate AZFc gene for male infertility. PMID:26655651

  10. Omega-3 Fatty Acid Ethyl Esters do not Improve Clopidogrel Associated P2Y12 Inhibition in Stroke Patients

    PubMed Central

    Li, Ping; Kamal, Haris; Baxter, Melissa; Mehta, Bijal K.

    2015-01-01

    The specific action of omega-3 fatty acid ethyl esters (OFA) in preventing cerebrovascular disease remains unknown, but research has demonstrated multiple possible mechanisms. In addition to altering lipid profiles, OFA may inhibit platelet aggregation. Clopidogrel inhibits platelets via the P2Y12 receptor. OFA may alter clopidogrel-associated platelet-inhibition via a possible combined effect on P2Y12 inhibition. To determine if OFA affects clopidogrel associated P2Y12 platelet receptor inhibition by comparing the percentage of responders in patients with cerebrovascular disease who were taking clopidogrel with or without OFA. We retrospectively reviewed data from adult patients with cerebrovascular disease or cerebral aneurysms and taking clopidogrel, who were seen at a single hospital between March 2010 to September 2011. We included 438 subjects in the study. For the 67 subjects who received loading doses of both clopidogrel and OFA, 71.6% had a P2Y12 inhibition response more than 20%, which is considered a positive response. For the 55 subjects who received just clopidogrel load, 67.2% of subjects were responders. There were 70.4% responders in the 274 subjects who were taking 75 mg of clopidogrel alone at home, and 73.8% responders in the 42 subjects who were taking both clopidogrel and OFA at home. However, these percentage differences were not statistically significant. This study did not find additional P2Y12 platelet inhibition when patients were given OFA, either given as a loading dose or taking it daily. PMID:26294943

  11. Enhancement of acid-sensing ion channel activity by metabotropic P2Y UTP receptors in primary sensory neurons.

    PubMed

    Ren, Cuixia; Gan, Xiong; Wu, Jing; Qiu, Chun-Yu; Hu, Wang-Ping

    2016-03-01

    Peripheral purinergic signaling plays an important role in nociception. Increasing evidence suggests that metabotropic P2Y receptors are also involved, but little is known about the underlying mechanism. Herein, we report that selective P2Y receptor agonist uridine 5'-triphosphate (UTP) can exert an enhancing effect on the functional activity of acid-sensing ion channels (ASICs), key sensors for extracellular protons, in rat dorsal root ganglia (DRG) neurons. First, UTP dose-dependently increased the amplitude of ASIC currents. UTP also shifted the concentration-response curve for proton upwards, with a 56.6 ± 6.4% increase of the maximal current response to proton. Second, UTP potentiation of proton-gated currents can be mimicked by adenosine 5'-triphosphate (ATP), but not by P2Y1 receptor agonist ADP. Potentiation of UTP was blocked by P2Y receptor antagonist suramin and by inhibition of intracellular G protein, phospholipase C (PLC), protein kinase C (PKC), or protein interacting with C-kinase 1 (PICK1) signaling. Third, UTP altered acidosis-evoked membrane excitability of DRG neurons and caused a significant increase in the amplitude of the depolarization and the number of spikes induced by acid stimuli. Finally, UTP dose-dependently exacerbated nociceptive responses to injection of acetic acid in rats. These results suggest that UTP enhanced ASIC-mediated currents and nociceptive responses, which reveal a novel peripheral mechanism underlying UTP-sensitive P2Y2 receptor involvement in hyperalgesia by sensitizing ASICs in primary sensory neurons. PMID:26538146

  12. Surface Quality Multicriteria Optimization of Flat Parts from 06Cr14Ni6Cu2MoVaTi-SH Steel While Grinding by Varigrain High Porosity CBN Wheels

    NASA Astrophysics Data System (ADS)

    Soler, Y. I.; Nguyen, M. T.

    2016-04-01

    The grinding of flat parts from 06Cr14Ni6Cu2MoVaTi-SH high-strength corrosion-resistant steel was made by the highly porous wheel (HPW) of CBN30 (B76, B107, B126, V151) 100 OVK27-KF40 (GOST R 53922-2010, GOST R 53923-2010). As input variables for fuzzy logic modeling in the Matlab the following description of the surface quality is chosen: the microrelief parameters (GOST 25142-82) - Ra1, Rmax1 in the cross-feed direction, Sm2 in the length feed direction, flatness deviation (GOST 24642-81) are introduced with the EFEmax , EFEa and EFEq ; microhardness HV. Every parameter at the model input is presented with position measures (medians) and scattering measures (quartile latitude). The Matlab modeling has shown that the best quality of the part surfaces is provided with HPW CBN30 B151 during the multicriteria optimization.

  13. A pure inorganic 1D chain based on {Mo8O28} clusters and Mn(II) ions: [Mn(H2O)2Mo8O28 ] n 6 n -

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaofen; Yan, Yonghong; Wu, Lizhou; Yu, Chengxin; Dong, Xinbo; Hu, Huaiming; Xue, Ganglin

    2016-01-01

    A new pure inorganic polymer, (NH4)6n[Mn(H2O)2Mo8O28)]n(H2O)2n(1), has been synthesized and characterized by elemental analyses, IR spectrum, UV-vis absorption spectra, TG-DSC and electrochemical studies. In 1, [Mo8O28]8- anions act as tetradentate ligands and are alternately linked by Mn(H2O)2 2 + ions into a one-dimensional chain structure. It is interesting that 1 represents the first example of pure inorganic-inorganic hybrid based on octamolybdate and transition metal ions. Moreover, it was indicated that 1 had definite catalytic activities on the probe reaction of benzyl alcohol oxidation to benzaldehyde with H2O2.

  14. Fatty Acid Composition of Adipose Tissues in Obese Mice and SD Rats Fed with Isaria sinclairii Powder

    PubMed Central

    Ahn, Mi Young; Seo, Yun Jung; Ji, Sang Deok; Han, Jea Woong; Hwang, Jae Sam; Yun, Eun Young

    2010-01-01

    Isaria sinclairii (Cicada Dongchunghacho) was studied as a potential crude natural food in powdered form. The role of tissue fatty acids in relation to the anti-obesity effects of I. sinclairii (IS) was examined by feeding the powder to SD rats ad libitum at 0, 1.25, 2.5, 5 and 10% (calculated about 8 g/kg) of the feed for a period of 3 months and 6 months. The fatty acid composition profile as indicated GC-MS, showed significantly slight dose-dependent increases in the levels of unsaturated fatty acids, particularly, arachidonic acid (C20: 4n6) , oleic acid, linoleic acid, eicosadienoic acid, eicosapentaenoic acid (EPA) (C20: 5) concentration in the the ad libitum IS-fed groups compared to the control group in SD abdominal fat over 6 month period. Over viewing of the SD and Ob mice treated Isaria sinclairii powder; there were increases in the single (mono) unsaturated fatty acids ratio but decreases in polyunsaturated fatty acid. In IS-fed groups in proportion to the treatment period, this Dongchunghacho also induced an increase in the level of same result of unsaturated fatty acid in C57BL/6 obese (ob/ob) mice over a 6-month period treatment compared to those given 10% dry mulberry leaf powder (ML) or silkworm powder mixed with the standard diet. PMID:24278523

  15. INSIGHT INTO THE MODE OF ACTION OF THE LRRK2 Y1699C PATHOGENIC MUTANT

    PubMed Central

    Daniëls, Veronique; Vancraenenbroeck, Renée; Law, Bernard MH; Greggio, Elisa; Lobbestael, Evy; Gao, Fangye; De Maeyer, Marc; Cookson, Mark R; Harvey, Kirsten; Baekelandt, Veerle; Taymans, Jean-Marc

    2010-01-01

    Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most prevalent known cause of autosomal dominant Parkinson's disease (PD). The LRRK2 gene encodes a Roco protein featuring a ROC GTPase and a kinase domain linked by the C-terminal of ROC (COR) domain. Here, we explored the effects of the Y1699C pathogenic LRRK2 mutation in the COR domain on GTPase activity and interactions within the catalytic core of LRRK2. We observed a decrease in GTPase activity for LRRK2 Y1699C comparable to the decrease observed for the R1441C pathogenic mutant and the T1348N dysfunctional mutant. To study the underlying mechanism, we explored the dimerization in the catalytic core of LRRK2. ROC-COR dimerization was significantly weakened by the Y1699C or R1441C/G mutation. Using a competition assay we demonstrated that the intra-molecular ROC:COR interaction is favoured over ROC:ROC dimerization. Interestingly, the intra-molecular ROC:COR interaction was strengthened by the Y1699C mutation. This is supported by a 3D homology model of the ROC-COR tandem of LRRK2, showing that Y1699 is positioned at the intra-molecular ROC:COR interface. In conclusion, our data provides mechanistic insight into the mode of action of the Y1699C LRRK2 mutant: the Y1699C substitution, situated at the intra-molecular ROC:COR interface, strengthens the intra-molecular ROC:COR interaction, thereby locally weakening the dimerization of LRRK2 at the ROC-COR tandem domain resulting in decreased GTPase activity. PMID:21073465

  16. Dehydroepiandrosterone replacement therapy in older adults: 1- and 2-y effects on bone123

    PubMed Central

    Weiss, Edward P; Shah, Krupa; Fontana, Luigi; Lambert, Charles P; Holloszy, John O; Villareal, Dennis T

    2009-01-01

    Background: Age-related reductions in serum dehydroepiandrosterone (DHEA) concentrations may be involved in bone mineral density (BMD) losses. Objective: The objective was to determine whether DHEA supplementation in older adults improves BMD when co-administered with vitamin D and calcium. Design: In year 1, a randomized trial was conducted in which men (n = 55) and women (n = 58) aged 65–75 y took 50 mg/d oral DHEA supplements or placebo. In year 2, all participants took open-label DHEA (50 mg/d). During both years, all participants received vitamin D (16 μg/d) and calcium (700 mg/d) supplements. BMD was measured by using dual-energy X-ray absorptiometry. Concentrations of hormones and bone turnover markers were measured in serum. Results: In men, no difference between groups occurred in any BMD measures or in bone turnover markers during year 1 or year 2. The free testosterone index and estradiol increased in the DHEA group only. In women, spine BMD increased by 1.7 ± 0.6% (P = 0.0003) during year 1 and by 3.6 ± 0.7% after 2 y of supplementation in the DHEA group; however, in the placebo group, spine BMD was unchanged during year 1 but increased to 2.6 ± 0.9% above baseline during year 2 after the crossover to DHEA. Hip BMD did not change. Testosterone, estradiol, and insulin-like growth factor 1 increased in the DHEA group only. In both groups, serum concentrations of bone turnover markers decreased during year 1 and remained low during year 2, but did not differ between groups. Conclusion: DHEA supplementation in older women, but not in men, improves spine BMD when co-administered with vitamin D and calcium. This trial was registered at clinicaltrials.gov as NCT00182975. PMID:19321570

  17. Using asymmetry analysis to reduce normal variability of Spectral Domain Optical Coherence Tomography (SD-OCT) macular thickness

    NASA Astrophysics Data System (ADS)

    Alluwimi, Muhammed Saad

    Purpose: To investigate the use of asymmetry analysis to reduce normal between-subject variability of macular thickness measurements using SD-OCT. Methods: 63 volunteers free of eye disease were recruited: 33 young subjects (ages 21 to 35 years with mean and SD of 25 +/- 1.7), and 30 older subjects (ages 45 to 85 years with mean and SD of 66.7 +/- 9.0). All participants passed a comprehensive ophthalmic examination within the past two years. Macular images were gathered with the Spectralis OCT (V 5.4, Heidelberg Engineering, GmbH). The overlay 8x8 grid was manually centered on the fovea and aligned with the foveal-disc axis, then divided into five zones per hemifield following the method of Um et al (2012 IOVS 53:1139); asymmetry was computed as the difference between superior and inferior zone thicknesses. We assumed that the lowest variation and the highest density of ganglion cells will be found ~3° to 6° from the foveal center, corresponding to zones 1 and 2. For each zone and age group, between-subject standard deviations (SDs) were compared for retinal thickness (RT) versus asymmetry using an F-test. To account for repeated measures, a probability of p < 0.0125 was required for statistical significance. Axial length (AL) and corneal curvature (CC) were measured with an IOLMaster by the same operator and during the same imaging session. Results: For OD, asymmetry analysis reduced between-subject variability in zones 1 and 2 in both groups (F > 3.2, p < 0.001). SD for zone 1 dropped from 12.0 to 3.0 mum in the young group and from 11.7 to 2.6 mum in the older group. SD for zone 2 dropped from 13.6 to 5.3 mum (young) and from 11.1 to 5.8 mum (older). Combining all subjects, neither RT nor asymmetry showed a strong correlation with AL or CC (R2 < 0.01). Analysis for OS yielded the same pattern of results, as did asymmetry analyses between eyes (F > 3.8, p < 0.0001). Conclusions: Asymmetry analysis reduced between-subject variability. These findings demonstrate

  18. Structure - property relationship of permutite-like amorphous silicates, Nax+2yM3+xSi1-xO2+y(M3+= Al, Mn, Fe, Y), for ion-exchange reactions.

    SciTech Connect

    Pless, Jason D.; Nenoff, Tina Maria; Maxwell, Robert S.; Phillips, Mark L. F.; Axness, Marlene

    2005-03-01

    A series of amorphous silicate materials with the general formula Na{sub x+2y}M{sub x}{sup 3+}Si{sub 1-x}O{sub 2+y}(M{sup 3+} = Al, Mn, Fe, Y) were studied. Samples were synthesized by a precipitation reaction at room temperature. The results indicate that the ion-exchange capacity (IEC) decreases as follows: Al > Fe > Mn > Y. Additionally, the IEC increases with increasing aluminum concentration. Structural studies show that the relative amount of octahedrally coordinated aluminum increases with increasing Al content, as does the total amount of AlO{sub 4} species increases. The data suggest that the IEC value of these amorphous aluminosilicates is dependent on the tetrahedrally coordinated aluminum. Regeneration of the Al-silicate with acetic acid does not decrease the IEC significantly.

  19. P2Y2 receptor activation decreases blood pressure via intermediate conductance potassium channels and connexin 37

    PubMed Central

    Dominguez Rieg, J. A.; Burt, J. M.; Ruth, P.; Rieg, T.

    2015-01-01

    Aims Nucleotides are important paracrine regulators of vascular tone. We previously demonstrated that activation of P2Y2 receptors causes an acute, NO-independent decrease in blood pressure, indicating this signalling pathway requires an endothelial-derived hyperpolarization (EDH) response. To define the mechanisms by which activation of P2Y2 receptors initiates EDH and vasodilation, we studied intermediate-conductance (KCa3.1, expressed in endothelial cells) and big-conductance potassium channels (KCa1.1, expressed in smooth muscle cells) as well as components of the myoendothelial gap junction, connexins 37 and 40 (Cx37, Cx40), all hypothesized to be part of the EDH response. Methods We compared the effects of a P2Y2/4 receptor agonist in wild-type (WT) mice and in mice lacking KCa3.1, KCa1.1, Cx37 or Cx40 under anaesthesia, while monitoring intra-arterial blood pressure and heart rate. Results Acute activation of P2Y2/4 receptors (0.01–3 mg kg−1 body weight i.v.) caused a biphasic blood pressure response characterized by a dose-dependent and rapid decrease in blood pressure in WT (maximal response % of baseline at 3 mg kg−1: −38 ± 1%) followed by a consecutive increase in blood pressure (+44 ± 11%). The maximal responses in KCa3.1−/− and Cx37−/− were impaired (−13 ± 5, +17 ± 7 and −27 ± 1, +13 ± 3% respectively), whereas the maximal blood pressure decrease in response to acetylcholine at 3 µg kg−1 was not significantly different (WT: −53 ± 3%; KCa3.1−/−: −52 ± 3; Cx37−/−: −53 ± 3%). KCa1.1−/− and Cx40−/− showed an identical biphasic response to P2Y2/4 receptor activation compared to WT. Conclusions The data suggest that the P2Y2/4 receptor activation elicits blood pressure responses via distinct mechanisms involving KCa3.1 and Cx37. PMID:25545736

  20. Clopidogrel and ticlopidine: P2Y12 adenosine diphosphate-receptor antagonists for the prevention of atherothrombosis.

    PubMed

    Savi, Pierre; Herbert, Jean-Marc

    2005-04-01

    Ticlopidine and clopidogrel belong to the same chemical family of thienopyridine adenosine diphosphate (ADP)-receptor antagonists. They have shown their efficacy as platelet antiaggregant and antithrombotic agents in many animal models, both ex vivo and in vivo. Although ticlopidine was discovered more than 30 years ago, it was only recently that the mechanism of action of ADP-receptor antagonists was characterized in detail. Ticlopidine and clopidogrel both behave in vivo as specific antagonists of P2Y (12), one of the ADP receptors on platelets. Metabolic steps that involve cytochrome P450-dependent pathways are required to generate the active metabolite responsible for this in vivo activity. The active moiety is a reactive thiol derivative that targets P2Y (12) on platelets. The interaction is irreversible, accounting for the observation that platelets are definitely antiaggregated, even if no active metabolite is detectable in plasma. The interaction is specific for P2Y (12); other purinoceptors such as P2Y (1) and P2Y (13) are spared. This results in inhibition of the binding of the P2Y (12) agonist 2-methylthio-ADP and the ADP-induced downregulation of adenylyl cyclase. Platelet aggregation is affected not only when triggered by ADP but also by aggregation inducers when used at concentrations requiring released ADP as an amplifier. The efficacy and safety of clopidogrel has been established in several large, randomized, controlled trials. The clopidogrel versus aspirin in patients at risk of ischaemic events (CAPRIE) trial demonstrated the superiority of clopidogrel over acetylsalicylic acid (ASA) in patients at risk of ischemic events, including ischemic stroke, myocardial infarction (MI), and peripheral arterial disease. The clopidogrel in unstable angina to prevent recurrent ischemic events (CURE) trial showed a sustained, incremental benefit when clopidogrel was added to standard therapy (including ASA) in patients with unstable angina and non-Q-wave MI