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Sample records for 2 3 7

  1. Ca3Mn2O7.

    PubMed

    Guiblin, Nicolas; Grebille, Dominique; Leligny, Henri; Martin, Christine

    2002-01-01

    The tricalcium dimanganese heptaoxide (Ca3Mn2O7) member of the Ruddlesden-Popper series Ca(n+1)Mn(n)O(3n+1), i.e. with n = 2, was previously reported with an I-centred tetragonal lattice [a(t) = 3.68 and c(t) = 19.57 A] by Fawcett, Sunstrom, Greenblatt, Croft & Ramanujachary [Chem. Mater. (1998), 10, 3643-3651]. It is now found to be orthorhombic, with an A-centred lattice [a = 5.2347 (6), b = 5.2421 (2) and c = 19.4177 (19) A]. The structure has been refined in space group A2(1)am using X-ray single-crystal diffraction data and assuming the existence of twin domains related by the (1-10) plane. A comparison with the basic perovskite structure CaMnO3 (n = infinity) is proposed.

  2. 2.7 μm emission properties of Er3+/Yb3+/Eu3+: SrGdGa3O7 and Er3+/Yb3+/Ho3+: SrGdGa3O7 crystals

    NASA Astrophysics Data System (ADS)

    Xia, Houping; Feng, Jianghe; Ji, Yuexia; Sun, Yijian; Wang, Yan; Jia, Zhitai; Tu, Chaoyang

    2016-04-01

    Er3+/Yb3+/Eu3+: SrGdGa3O7 and Er3+/Yb3+/Ho3+: SrGdGa3O7 crystals were grown by Czochralski technology and detailed spectroscopic analyses were carried out. It was found that the spectra of Er3+/Yb3+/Eu3+: SrGdGa3O7 crystal show weaker near-infrared emission and stronger mid-infrared emission as compared with Er3+/Yb3+: SrGdGa3O7 crystal. Furthermore, the lifetime of the 4I13/2 state decreases from 10.58 ms in Er3+/Yb3+: SrGdGa3O7 crystal to 6.87 ms in Er3+/Yb3+/Eu3+: SrGdGa3O7 crystal, that is, the self-saturation for 2.7 μm laser in Er3+/Yb3+/Eu3+: SrGdGa3O7 crystal is suppressed greatly. These results indicate that the doping of Eu3+ in Er3+/Yb3+: SrGdGa3O7 crystal is beneficial to improve the 2.7 μm laser. In contrast, introducing Ho3+ in Er3+/Yb3+: SrGdGa3O7 crystal is adverse to realize Er3+-activated MIR laser operation. So Er3+/Yb3+/Eu3+: SrGdGa3O7 crystal could be a potential MIR gain media for enhanced 2.7 μm laser.

  3. NIR emission from Yb3+-Er3+ ions in Y2Sn2O7 host

    NASA Astrophysics Data System (ADS)

    Nigam, Sandeep; Sarkar, Kaustabh; Prasad, A. I.; Sudarsan, V.; Vatsa, R. K.

    2015-06-01

    Er and Yb-Er co-doped Y2Sn2O7 both in the bulk and nano-size dimensions were prepared via co-precipitation method and investigated for their photoluminescence properties. Characteristic near Infra-Red (NIR) emission at 1530 nm due to4I13/2→4I15/2 transition of Er3+ was observed in both bulk and nanoparticles of Er doped as well as Yb-Er co-doped Y2Sn2O7. Intensity of emission improves systematically with increase in heat treatment temperature and the bulk sample show improved luminescence with crystal field splitting. Co-doping Y2Sn2O7: Er with Yb3+ ions enhances the NIR emission intensity from Er3+ ion, which is attributed to energy transfer. Excitation spectra also revealed the back energy transfer from Er3+ to Yb3+ ion.

  4. Three new phosphates with isolated P2O7 units: noncentrosymmetric Cs2Ba3(P2O7)2 and centrosymmetric Cs2BaP2O7 and LiCsBaP2O7.

    PubMed

    Li, Lin; Han, Shujuan; Lei, Bing-Hua; Wang, Ying; Li, Hongyi; Yang, Zhihua; Pan, Shilie

    2016-03-01

    Three new phosphates, a noncentrosymmetric (NCS) Cs2Ba3(P2O7)2 and centrosymmetric (CS) Cs2BaP2O7 and LiCsBaP2O7, have been synthesized from high-temperature solutions for the first time. Analysis of the structures determined by single-crystal X-ray diffraction showed that although the three compounds contained isolated P2O7 units, they yielded different three-dimensional (3D) networks: Cs2Ba3(P2O7)2 crystallized in the NCS Orthorhombic space group P212121, Cs2BaP2O7 in the CS monoclinic space group P21/n, and LiCsBaP2O7, having an identical stoichiometry with Cs2BaP2O7, crystallized in monoclinic space group, P21/c. Structural comparisons suggested the differences between their 3D frameworks to be due to differences between the sizes and coordination environments of the cations. Characterizations including thermal and optical analyses showed Cs2Ba3(P2O7)2 and Cs2BaP2O7 to melt congruently, and Cs2Ba3(P2O7)2 to exhibit a wide transparent region with a cut-off edge below 176 nm. The NLO properties and electronic structures of these compounds were investigated using first-principles calcualtions. PMID:26831497

  5. In2O3/Bi2Sn2O7 heterostructured nanoparticles with enhanced photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Xing, Yonglei; Que, Wenxiu; Yin, Xingtian; He, Zuoli; Liu, Xiaobin; Yang, Yawei; Shao, Jinyou; Kong, Ling Bing

    2016-11-01

    In2O3/Bi2Sn2O7 composite photocatalysts with various contents of cubic In2O3 nanoparticles were fabricated by using impregnation method. A thriving modification of Bi2Sn2O7 by an introduction of In2O3 was confirmed by using X-ray diffraction, UV-vis diffuse reflectance spectrometry, transmission electron microscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The samples composed of hybrids of In2O3 and Bi2Sn2O7 exhibited a much higher photocatalytic activity for the degradation of Rhodamine B under visible light, as compared with pure In2O3 and Bi2Sn2O7 nanoparticles. Optimized composition of the composite photocatalysts was 0.1In2O3/Bi2Sn2O7, which shows a rate constant higher than those of pure In2O3 and Bi2Sn2O7 by 4.06 and 3.21 times, respectively. Based on Mott-Schottky analysis and active species detection, the photoexcited electrons in the conduction band of In2O3 and the holes in the valence band of Bi2Sn2O7 participated in reduction and oxidation reactions, respectively. Hence, rad OH, rad O2- and h+ were the main active species involved in the photocatalytic reaction of the In2O3/Bi2Sn2O7 composite photocatalysts. The effective separation process of the photogenerated electron-hole pairs was testified by photocurrent test.

  6. Thermodynamic Study on YBa2Cu3C7-x

    NASA Astrophysics Data System (ADS)

    Toci, F.; Schuerenkaemper, A.; Toussaint, N.; Cambini, M.; Manes, L.

    Results are related to ordering of oxygen vacancies in the YBa2Cu3O7-x lattice. The concentration and ordering of oxygen in the lattice of YBa2Cu3O7-x are fundamental for its superconducting properties. Partial free energies, enthalpies and entropies of YBa2Cu3O7-x have been obtained from oxygen standard potential measurements performed between 700 and 1100 K, by means of a miniaturized solid state galvanic cell. The oxygen molar content of the phases investigated was between 6.65 and 6.95. Oxygen diffusion kinetics was also studied by means of the same apparatus, by following the depolarization of the electrode after a coulometric titration. Structural characterization was performed by X-ray powder diffraction, metallography and scanning electron microscopy.

  7. Synthesis and Photoluminescence Properties of Sr2Be2B2O7 Doped with Dy3+, Sm3+, Tb3+, and Pb2+

    NASA Astrophysics Data System (ADS)

    Pekgözlü, İ.; Karabulut, H.; Mergen, A.; Basak, A. S.

    2016-07-01

    Pure and Dy3+-, Sm3+-, Tb3+-, and Pb2+-doped Sr2Be2B2O7 materials were prepared by a solution combustion synthesis method. The phase analysis of all synthesized materials was carried out using powder XRD. The photoluminescent properties of Dy3+-, Sm3+-, Tb3+-, and Pb2+-doped Sr2Be2B2O7 materials were investigated using a spectrofl uorometer at room temperature. The fi rst luminescent material, Sr2Be2B2O7:Dy3+, emits 478-493, 573, and 661 nm upon excitation with 344 nm; Sr2Be2B2O7:Sm3+ emits 563-574, 599-613, 647-666, and 705-713 nm upon excitation with 395 nm; Sr2Be2B2O7:Tb3+ emits 489, 545, 584-591, and 622 nm upon excitation with 248 nm; Sr2Be2B2O7:Pb2+ emits 371 nm upon excitation with 281 nm. Also, the dependence of the emission intensity on the activator ion (Dy3+, Sm3+, Tb3+, and Pb2+) concentration for the Sr2Be2B2O7 was studied. It was observed that the concentration quenching of Dy3+, Sm3+, Tb3+, and Pb2+ in Sr2Be2B2O7 is 0.05, 0.02, 0.07, and 0.02 mol.%, respectively.

  8. 12Cao-7Al2o3 Electride Hollow Cathode

    NASA Technical Reports Server (NTRS)

    Rand, Lauren P. (Inventor); Williams, John D. (Inventor); Martinez, Rafael A. (Inventor)

    2016-01-01

    The use of the electride form of 12CaO-7Al.sub.2O.sub.3, or C12A7, as a low work function electron emitter in a hollow cathode discharge apparatus is described. No heater is required to initiate operation of the present cathode, as is necessary for traditional hollow cathode devices. Because C12A7 has a fully oxidized lattice structure, exposure to oxygen does not degrade the electride. The electride was surrounded by a graphite liner since it was found that the C12A7 electride converts to it's eutectic (CA+C3A) form when heated (through natural hollow cathode operation) in a metal tube.

  9. 2,3,7,8-Tetrachlorodibenzo-p-dioxin

    Integrated Risk Information System (IRIS)

    2,3,7,8 - Tetrachlorodibenzo - p - dioxin ( TCDD ) ; CASRN 1746 - 01 - 6 This document has been provided for review to EPA scientists , interagency reviewers from other federal agencies and White House offices , and the public , and peer reviewed by independent scientists external to EPA . Sections

  10. Radioimmunoassay for quantitation of 2,3,7,8-tetrachlorodibenzofuran

    SciTech Connect

    Luster, M.I.; Albro, P.W.; Chae, K.; Lawson, L.D.; Corbett, J.T.; McKinney, J.D.

    1980-08-01

    A radioimmunoassay is described for the determination of 2,3,7,8-tetrachlorodibenzofuran (TCDF) in commercial preparations of polychlorinated biphenyls (PCBs) as well as environmental samples including animal tissues. A feature of the assay method is the use of nonionic detergent to solubilize the hydrophobic dibenzofurans in a manner permitting their binding to antibodies. The detection limits of the assay range between 20 pg and 4.0 ng of 2,3,7,8-TCDF. Extensive cross-reactivity studies indicated that the antiserum was fairly specific for TCDF although some cross-reactivity was found to structurally similar compounds. Values for TCDF in various Aroclors and animal tissues by radioimmunoassay correlated with those obtained by gas chromatography-mass spectrometry analysis. The radioimmunoassay is applicable to screening samples in order to minimize the demand for mass spectrometric screening and should be simple enough to be performed in most clinical laboratories. 3 tables, 1 figure.

  11. A comparative study of Li8NaV3(P2O7)3(PO4)2 and Li9V3(P2O7)3(PO4)2: Synthesis, structure and electrochemical properties

    NASA Astrophysics Data System (ADS)

    Kuang, Quan; Zhao, Yanming; Dong, Youzhong; Fan, Qinghua; Lin, Xinghao; Liu, Xudong

    2016-02-01

    The energy-density improvement for cathode materials by using the method of occupying the Li site with the lowest formation enthalpy was first presented, and successfully applied to Li9V3(P2O7)3(PO4)2. Herein, the synthesis, structure and electrochemical properties (including both Li extraction and intercalation) of mixed alkali-ion phosphate Li8NaV3(P2O7)3(PO4)2 were comprehensively studied, and compared with its isologue Li9V3(P2O7)3(PO4)2. Both Li8NaV3(P2O7)3(PO4)2 and Li9V3(P2O7)3(PO4)2 were synthesized via an original two-step method for the first time. The sintering temperature of Li8NaV3(P2O7)3(PO4)2 (650 °C) was much lower than that of Li9V3(P2O7)3(PO4)2 (750 °C). The Rietveld structure refinement indicated that Na ions occupied the Li1(2b) site of Li9V3(P2O7)3(PO4)2 as expected, and Li8NaV3(P2O7)3(PO4)2 showed a single charge plateau at 4.4 V vs. Li in the 1st cycle. However, the Na ions migrated from Li1(2b) site after the initial cycle, and the charge plateau at 3.7 V vs. Li reappeared. On the other hand, both Li9V3(P2O7)3(PO4)2 and Li8NaV3(P2O7)3(PO4)2 can deliver a high reversible capacity (∼200 mAh g-1), and reveal excellent cycle and rate performance in 3.0-0.05 V vs. Li. The gentle structure changes along with abundant Li intercalation into the bulks suggested that Li9V3(P2O7)3(PO4)2 and Li8NaV3(P2O7)3(PO4)2 were also promising anode materials for Li-ion batteries.

  12. Magnetothermal instabilities in YBa 2Cu 3O 7

    NASA Astrophysics Data System (ADS)

    Legrand, L.; Rosenman, I.; Simon, Ch.; Collin, G.

    1993-06-01

    We have studied the magnetothermal instabilities in YBa 2Cu 3O 7 by using thermal and magnetic measurements. These magnetothermal instabilities consist of flux jumps and temperature jumps, and quasiperiodic oscillations of the temperature and magnetization of the sample. We have interpreted these instabilities with the model primarily introduced by R.G. Mints but taking into account the form of the dissipated power we have found experimentally. The influence of the sweep rate of the applied magnetic field on the appearance of the first flux jump and on the periodicity of the oscillations has been studied. The results are in good agreement with the proposed model.

  13. Elliptical flux vortices in YBa2Cu3O7

    NASA Technical Reports Server (NTRS)

    Hickman, H.; Dekker, A. J.; Chen, T. M.

    1991-01-01

    The most energetically favorable vortex in YBa2Cu3O7 forms perpendicular to an anisotropic plane. This vortex is elliptical in shape and is distinguished by an effective interchange of London penetration depths from one axis of the ellipse to another. By generalizing qualitatively from the isotropic to the anisotropic case, we suggest that the flux flow resistivity for the vortex that forms perpendicular to an anistropic plane should have a preferred direction. Similar reasoning indicates that the Kosterlitz-Thouless transition temperature for a vortex mediated transition should be lower if the vortex is elliptical in shape.

  14. Fragrance material review on 3,7-dimethyl-7-methoxyoctan-2-ol.

    PubMed

    McGinty, D; Scognamiglio, J; Letizia, C S; Api, A M

    2010-07-01

    A toxicologic and dermatologic review of 3,7-dimethyl-7-methoxyoctan-2-ol when used as a fragrance ingredient is presented. 3,7-Dimethyl-7-methoxyoctan-2-ol is a member of the fragrance structural group branched chain saturated alcohols. The common characteristic structural elements of the alcohols with saturated branched chain are one hydroxyl group per molecule, and a C(4)-C(12) carbon chain with one or several methyl side chains. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. A safety assessment of the entire branched chain saturated alcohol group will be published simultaneously with this document; please refer to Belsito et al. (2010) for an overall assessment of the safe use of this material and all other branched chain saturated alcohols in fragrances.

  15. AC magnetic response of superconducting YBa2Cu3O7/PrBa2Cu3O7 superlattices

    NASA Astrophysics Data System (ADS)

    Miu, L.; Ivan, I.; Ionescu, A. M.; Miu, D.

    2016-06-01

    Vortex activation energy UAC in the critical-state related AC magnetic response of superconductors (appearing in the vicinity of the DC irreversibility line) takes large values, as often reported, which is not yet understood. This behavior is essentially different from that of the vortex-creep activation energy at long relaxation time scales, and may become important for AC applications of superconductors. To elucidate this aspect, we investigated the AC signal of almost decoupled [Y Ba2Cu3O7]n/[PrBa2Cu3O7]4 superlattices (with n = 11 or 4 units cells) in perpendicular DC and AC magnetic fields. In these model samples, the length of the hopping vortex segment is fixed by the thickness of superconducting layers and vortices are disentangled, at least at low DC fields. It is shown that the high UAC values result from the large contribution of the pinning enhanced viscous drag in the conditions of thermally activated, non-diffusive vortex motion at short time scales, where the influence of thermally induced vortex fluctuations on pinning is weak.

  16. ARTICLES: Theoretical Study on Destruction Mechanism of 2,3,7,8-TCDD by O3 and NO3

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-hua; Wen, Zheng-cheng; Xu, Jiang-rong; Zhou, Jun-hu; Cen, Ke-fa

    2010-06-01

    In order to improve the destruction efficiency of dioxins and also for developing new dioxin control technology, the destruction mechanisms of 2,3,7,8-tetrachlorodihenzo-p-dioxin (2,3,7,8-TCDD) by O3 and NO3, were investigated employing quantum chemical calculations. For involved reactions, the microcosmic reaction processes were analyzed and depicted in detail based on geometry optimizations made by the B3LYP/6-31G(d) method. At the same time, the reaction activation energies were also calculated at the MP2/6-311G(d,p)//B3LYP/6-31G(d) level. Configuration analysis indicated that 2,3,7,8-TCDD could be destroyed by O3 and NO3 in two different ways. The destruction of 2,3,7,8-TCDD by O3 proceeded via the addition of O3 and the cleavage of C = C while the destruction of 2,3,7,8-TCDD by NO3 proceeded via the substitution of chlorine by NO3. Calculated results show that, the activation energy of the destruction reaction of 2,3,7,8-TCDD by NO3 (267.48 kJ/mol) is much larger than that of the destruction reaction of 2,3,7,8-TCDD by O3 (51.20 kJ/mol). This indicated that the destruction of 2,3,7,8-TCDD by O3 is much more efficient than that of 2,3,7,8-TCDD by NO3. The reason why the activation energy for the destruction reaction of 2,3,7,8-TCDD by NO3 is so large, is also discussed.

  17. Multiple superconducting transitions in the Sr3Ru2O7 region of Sr3Ru2O7-Sr2RuO4 eutectic crystals

    NASA Astrophysics Data System (ADS)

    Kittaka, S.; Fusanobori, S.; Yonezawa, S.; Yaguchi, H.; Maeno, Y.; Fittipaldi, R.; Vecchione, A.

    2008-06-01

    We report the superconducting properties of Sr3Ru2O7-Sr2RuO4 eutectic crystals, which consist of the spin-triplet superconductor Sr2RuO4 with a monolayer stacking of RuO2 planes and the metamagnetic normal metal Sr3Ru2O7 with a bilayer stacking. Although Sr3Ru2O7 so far has not been reported to exhibit superconductivity, our ac susceptibility measurements revealed multiple superconducting transitions that occur in the Sr3Ru2O7 region of the eutectic crystals. The diamagnetic shielding essentially reached the full fraction at low ac fields parallel to the c axis. However, both the shielding fraction and the onset temperature are easily suppressed by ac fields larger than 0.1 mT rms and no anomaly was observed in the specific heat. Moreover, the critical field curves of these transitions have a positive curvature near zero fields, which is different from the upper critical field curve of the bulk Sr2RuO4 . These facts suggest that the superconductivity observed in the Sr3Ru2O7 region is not a bulk property. To explain these experimental results, we propose the scenario that stacking RuO2 planes, which are the building blocks of superconducting Sr2RuO4 , are contained in the Sr3Ru2O7 region as stacking faults.

  18. Isolation and characterization of rabbit anti-m3 2,2,7G antibodies.

    PubMed

    Luhrmann, R; Appel, B; Bringmann, P; Rinke, J; Reuter, R; Rothe, S; Bald, R

    1982-11-25

    Antibodies specific for intact 2,2,7-trimethylguanosine (m3 2,2,7G) were induced by immunization of rabbits with a nucleoside-human serum albumen (HSA) conjugate. Competition radioimmunoassay showed that the antibody distinguishes well between intact m3 2,2,7G and its alkali-hydrolysed form (m3 2,2,7G*). Antibody specificity is largely dependent on the presence of all three methyl groups in m3 2,2,7G: none of the less extensively methylated nucleosides m7G, m2G and m2 2,2G is able to compete efficiently with the homologous hapten. Little or no competition was observed with m1G, m1A, m6A, m5U and each of the four unmodified ribonucleosides. Binding studies with nucleoplasmic RNAs from Ehrlich ascites cells suggest that the antibody reacts specifically with the m3 2,2,7G-containing cap structure of the small nuclear U-RNAs (U-snRNAs). Thus the antibody should be a valuable tool for studying the role of the 5'-terminal regions of the U-snRNAs of eucaryotic cells. PMID:7155893

  19. 7 CFR 1216.2-1216.3 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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  20. 7 CFR 1216.2-1216.3 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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  1. 7 CFR 1216.2-1216.3 - [Reserved

    Code of Federal Regulations, 2014 CFR

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  2. 7 CFR 1216.2-1216.3 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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  3. 7 CFR 1216.2-1216.3 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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  4. Wet chemical techniques for passivation of YBa2Cu3O7(7-x)

    NASA Technical Reports Server (NTRS)

    Vasquez, R. P.; Foote, M. C.; Hunt, B. D.

    1989-01-01

    Wet chemical techniques are described for treatment of YBa2Cu3O(7-x) surfaces, resulting in the formation of native compounds with little or no reactivity to water. Promising native compounds include CuI, BaSO4, CuS, Cu2S, and the oxalates, all of which are either insoluble or have very low solubility in water. Treatment with dilute HI results in the formation of a native iodide film which is 80-90 percent CuI with small amounts of YI3 and BaI2. Treatment with dilute H2SO4 results in the formation of a film which is 95 percent BaSO4 and 5 percent Y2(SO4)3. Cu2S is formed on the surface with a dilute Na2S solution. An oxalate film with equal amounts of Y2(C2O4)3 and BaC2O4 results from treatment with dilute oxalic acid. X-ray photoelectron spectra show no significant changes when the sulfide, sulfate, or oxalate films are dipped in water, while the iodide film shows evidence of Cu(OH)2 formation.

  5. Non-isovalent substitution of Ba 2+ in superconducting YBa 2Cu 3O 7-y

    NASA Astrophysics Data System (ADS)

    Rajarajan, A. K.; Guptasarma, P.; Palkar, V. R.; Ayyub, P.; Multani, M. S.; Gupta, L. C.; Vijayaraghavan, R.

    1988-06-01

    We report the structural, magnetic and superconducting properties of YBa2-xMxCu3O7 (M=La3+ or K+). Single-phase compounds form over a wide range of x in YBa2-xMxCu3O7 and up to x = 0.2 in YBa2-xMxCu3O7. A substituent concentration of 15% triggers an orthorhombic to tetragonal phase15 transition in both systems. In spite of the associated disorder in the Cu(1)-0(1) chains, such a transition does not affect Tc drastically. Tc gets systematically depressed with increasing x. A temperature-dependent paramagnetic response is observed in YBa2-xMxCu3O7 between 90 and 300K.

  6. 40 CFR 721.9577 - Chromate(3-), bis[7-[(aminohydroxyphenyl)azo]-3-[[5-(aminosulfonyl)-2-hydroxyphenyl] azo]-4...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7- -1-propenyl]azo]-2-naphthalenesulfonato(3-)]-, trisodium (9CI... Substances § 721.9577 Chromate(3-), bis -3- azo]-4-hydroxy-2-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7...]-4-hydroxy-2-naphthalenesulfonato (3-)]-,- azo]-4-hydroxy-7- -1-propenyl]azo]-2-naphthalene...

  7. 40 CFR 721.9577 - Chromate(3-), bis[7-[(aminohydroxyphenyl)azo]-3-[[5-(aminosulfonyl)-2-hydroxyphenyl] azo]-4...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7- -1-propenyl]azo]-2-naphthalenesulfonato(3-)]-, trisodium (9CI... Substances § 721.9577 Chromate(3-), bis -3- azo]-4-hydroxy-2-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7...]-4-hydroxy-2-naphthalenesulfonato (3-)]-,- azo]-4-hydroxy-7- -1-propenyl]azo]-2-naphthalene...

  8. 40 CFR 721.9577 - Chromate(3-), bis[7-[(aminohydroxyphenyl)azo]-3-[[5-(aminosulfonyl)-2-hydroxyphenyl] azo]-4...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7- -1-propenyl]azo]-2-naphthalenesulfonato(3-)]-, trisodium (9CI... Substances § 721.9577 Chromate(3-), bis -3- azo]-4-hydroxy-2-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7...]-4-hydroxy-2-naphthalenesulfonato (3-)]-,- azo]-4-hydroxy-7- -1-propenyl]azo]-2-naphthalene...

  9. 40 CFR 721.9577 - Chromate(3-), bis[7-[(aminohydroxyphenyl)azo]-3-[[5-(aminosulfonyl)-2-hydroxyphenyl] azo]-4...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7- -1-propenyl]azo]-2-naphthalenesulfonato(3-)]-, trisodium (9CI... Substances § 721.9577 Chromate(3-), bis -3- azo]-4-hydroxy-2-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7...]-4-hydroxy-2-naphthalenesulfonato (3-)]-,- azo]-4-hydroxy-7- -1-propenyl]azo]-2-naphthalene...

  10. 40 CFR 721.9577 - Chromate(3-), bis[7-[(aminohydroxyphenyl)azo]-3-[[5-(aminosulfonyl)-2-hydroxyphenyl] azo]-4...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7- -1-propenyl]azo]-2-naphthalenesulfonato(3-)]-, trisodium (9CI... Substances § 721.9577 Chromate(3-), bis -3- azo]-4-hydroxy-2-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7...]-4-hydroxy-2-naphthalenesulfonato (3-)]-,- azo]-4-hydroxy-7- -1-propenyl]azo]-2-naphthalene...

  11. Occurrence and metabolism of 7-hydroxy-2-indolinone-3-acetic acid in Zea mays

    NASA Technical Reports Server (NTRS)

    Lewer, P.; Bandurski, R. S.

    1987-01-01

    7-Hydroxy-2-indolinone-3-acetic acid was identified as a catabolite of indole-3-acetic acid in germinating kernels of Zea mays and found to be present in amounts of ca 3.1 nmol/kernel. 7-Hydroxy-2-indolinone-3-acetic acid was shown to be a biosynthetic intermediate between 2-indolinone-3-acetic acid and 7-hydroxy-2-indolinone-3-acetic acid-7'-O-glucoside in both kernels and roots of Zea mays. Further metabolism of 7-hydroxy-2-[5-3H]-indolinone-3-acetic acid-7'-O-glucoside occurred to yield tritiated water plus, as yet, uncharacterized products.

  12. Teachers Teaching Teachers (T3) [TM]. Vol. 2 No. 7

    ERIC Educational Resources Information Center

    Richardson, Joan, Ed.

    2007-01-01

    This issue of "Teachers Teaching Teachers" ("T3") focuses on coaches' role in the professional development of teachers. It contains the following articles: (1) An Excerpt from "Taking the Lead" (Joellen Killion and Cindy Harrison); (2) Be Like a Virus and Connect (Bill Ferriter); (3) No. 1 Resource Has a Human Face (Joellen Killion); (4) With This…

  13. 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.

  14. Cowabenzophenones A and B, two new tetracyclo[7.3.3.3(3,11).0(3,7)]tetradecane-2,12,14-trione derivatives, from ripe fruits of Garcinia cowa.

    PubMed

    Sriyatep, Teerayut; Maneerat, Wisanu; Sripisut, Tawanun; Cheenpracha, Sarot; Machan, Theeraphan; Phakhodee, Wong; Laphookhieo, Surat

    2014-01-01

    Two new tetracyclo[7.3.3.3(3,11).0(3,7)]tetradecane-2,12,14-trione derivatives, cowabenzophenones A (1) and B (2), were isolated from ripe fruits of Garcinia cowa Roxb. Their structures were determined by spectroscopic methods. The tetracyclo[7.3.3.3(3,11).0(3,7)]tetradecane-2,12,14-trione skeleton from the Garcinia genus is reported for the first time. PMID:24334104

  15. Synthesis and Antiproliferative Activity of [RuCp(PPh3)2(HdmoPTA)](OSO2CF3)2 (HdmoPTA = 3,7-H-3,7-Dimethyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane).

    PubMed

    Mendoza, Zenaida; Lorenzo-Luis, Pablo; Serrano-Ruiz, Manuel; Martín-Batista, Elva; Padrón, José M; Scalambra, Franco; Romerosa, Antonio

    2016-08-15

    The complex [RuCp(PPh3)2(HdmoPTA)](OSO2CF3)2 (2; HdmoPTA = 3,7-H-3,7-dimethyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane) was synthesized and characterized. Its crystal structure was determined by single-crystal X-ray diffraction. The complex showed a more potent antiproliferative activity than cisplatin against a representative panel of human cancer cells. PMID:27462992

  16. All a-axis oriented YBa2Cu3O(7-y) - PrBa2Cu3O(7-z) - YBa2Cu3O(7-y) Josephson devices operating at 80 K

    NASA Technical Reports Server (NTRS)

    Barner, J. B.; Rogers, C. T.; Inam, A.; Ramesh, R.; Bersey, S.

    1991-01-01

    The controllable, reproducible fabrication of nonhysteretic Josephson devices with excess-current weak-link characteristics at temperatures up to 80 K have been demonstrated. The devices are patterned from in situ deposited a-axis oriented YBa2Cu3O(7-y) - PrBa2Cu3O(7-y) - YBa2Cu3O(7-y) trilayers grown on SrTiO3(001) substrates. Control of the critical current density and resistance is achieved by varying the thickness of the PrBa2Cu3O(7-z) barrier layer. Critical current densities in excess of 10,000 A/sq cm have been reproducibly measured; good uniformity across the wafer is obtained with device parameters scaling with device area. Strong constant-voltage current steps are observed under 11.2 GHz microwave radiation at temperatures up to and above 80 K.

  17. Synthesis and luminescent properties of nanoscale Gd2Si2O7:Eu3+ phosphors.

    PubMed

    Li, Yong; Wang, Chao-Nan; Wei, Xian-Tao; Zhao, Jiang-Bo; Zhang, Wei-Ping; Yin, Min

    2010-03-01

    Gd2Si2O7:Eu3+ nanoparticles were prepared by the sol-gel method with citric acid as an additive in the precursor solutions. The crystal structure was analyzed by means of X-ray diffraction (XRD). The results indicate that the alpha-Gd2Si2O7 powders in size 35 nm are obtained at a synthesis temperature of 1,100 degrees C, and the doping ion contents do not influence the crystal structure. The excitation and emission spectra of samples were measured. The dependence of photoluminescence intensity and lifetime of level on Eu3+ concentration and synthesis temperature of samples are also discussed.

  18. Method for preparation of 7-hydroxy-1,2,3,4-tetrahydroquinoline from 1,2,3,4-tetrahydroquinoline

    DOEpatents

    Field, G.; Hammond, P.R.

    1994-02-01

    Methods for the efficient preparation of 7-hydroxy-1,2,3,4-tetrahydroquinoline include a first method in which the acylation of m-aminophenol obtains a lactam which is reduced to give the desired quinoline and a second method in which tetrahydroquinoline is nitrated and hydrogenated and then hydrolyzed to obtain the desire quinoline. 7-hydroxy-1,2,3,4-tetrahydroquinoline is used in the efficient synthesis of four lasing dyes of the rhodamine class.

  19. Dual fluorescence from an isonido ReIII rhenacarborane phosphine complex, [7,10-mu-H-7-CO-7,7-(PPh3)2-isonido-7,8,9-ReC2B7H9].

    PubMed

    Buckner, Steven W; Fischer, Matthew J; Jelliss, Paul A; Luo, Rensheng; Minteer, Shelley D; Rath, Nigam P; Siemiarczuk, Aleksander

    2006-09-01

    The complex [7,10-mu-H-7-CO-7,7-(PPh3)2-isonido-7,8,9-ReC2B7H9] has been synthesized by treatment of the complex salt [NHMe3][3,3-Cl2-3,3-(CO)2-closo-3,1,2-ReC2B9H11] with PPh3 in refluxing THF (tetrahydrofuran) and isolated as intensely colored orange-red microcrystals. Spectroscopic NMR and IR data have suggested that the product has a highly asymmetric structure with two inequivalent PPh3 ligands and a single CO ligand. Measurement of 11B NMR spectra in particular have indicated seven distinct boron vertexes, although the resulting cage degradation by removal of two BH vertexes was confirmed only following X-ray crystallographic analysis, which revealed the pentadecahedral isonido-7,8,9-ReC2B7 architecture. The 11B NMR resonances span an enormous chemical shift range (Deltadelta = 113), and this appears to be a direct consequence of the deshielding of the boron vertex directly opposite the quadrilateral |ReCCB| aperture. The new complex has been shown by electrochemical measurements to undergo a reversible one-electron oxidation. Digitally simulated cyclic voltammograms support a proposed square scheme (E(1/2) = 0.58, 0.69 V vs ferrocene) involving a reversible isonido-closo transition of the metallacarborane cage. Most unusually for a metallacarborane complex, ambient temperature solutions in CH2Cl2 and DMF have been shown to be intensely turquoise-blue fluorescent (lambda(em) = 442 nm, Phi = 0.012). Fluorescence spectroscopy measurements in MeTHF (2-methyltetrahydrofuran) glass at 77 K have indicated that the likely cause of such a broad emission is dual fluorescence (lambda(em) = 404, 505 nm), with both emissions displaying vibronic structure. Following excited-state lifetime decay analysis, the emissive behavior has been accredited to metal-perturbed 1IL states, with the lower energy emission arising from a slight geometric distortion of the initially excited complex.

  20. Determination of magic wavelengths for the 7 s 1/2 2S -7 p 3/2, 1/2 2P transitions in Fr

    NASA Astrophysics Data System (ADS)

    Singh, Sukhjit; Sahoo, B. K.; Arora, Bindiya

    2016-08-01

    Magic wavelengths (λmagic) for the 7 S1 /2-7 P1 /2 ,3 /2 transitions (D lines) in Fr were reported by Dammalapati et al. [U. Dammalapati, K. Harada, and Y. Sakemi, Phys. Rev. A 93, 043407 (2016), 10.1103/PhysRevA.93.043407]. These λmagic were determined by plotting dynamic polarizabilities (α ) of the involved states with the above transitions against a desired range of wavelengths. Electric dipole (E1) matrix elements listed in [J. E. Sansonetti, J. Phys. Chem. Ref. Data 36, 497 (2007), 10.1063/1.2719251], from the measured lifetimes of the 7 P1 /2 ,3 /2 states and from the calculations considering core-polarization effects in the relativistic Hartree-Fock (HFR) method, were used to determine α . However, contributions from core correlation effects and from the E1 matrix elements of the 7 P -7 S , 7 P -8 S , and 7 P -6 D transitions to α of the 7 P states were ignored. In this work, we demonstrate importance of these contributions and improve accuracies of α further by replacing the E1 matrix elements taken from the HFR method by the values obtained employing relativistic coupled-cluster theory. Our static α are found to be in excellent agreement with the other available theoretical results, whereas substituting the E1 matrix elements used by Dammalapati et al. gives very small α values for the 7 P states. Owing to this, we find disagreement in λmagic reported by Dammalapati et al. for linearly polarized light, especially at wavelengths close to the D lines and in the infrared region. As a consequence, a λmagic reported at 797.75 nm which was seen supporting a blue detuned trap in their work is now estimated at 771.03 nm and is supporting a red detuned trap. Also, none of our results match with the earlier results for circularly polarized light. Moreover, our static values of α will be very useful for guiding experiments to carry out their measurements.

  1. 1,5-Dichloro-3(2,7),7(2,7)-dinaphthal-ena-2,4,6,8-tetra-oxa-1(2,6),5(2,6)-di(1,3,5-triazina)octa-phane.

    PubMed

    Sang, Qiu-Guang; Yang, Jing-Kui

    2011-09-01

    In the macrocyclic title compound, C(26)H(12)Cl(2)N(6)O(4), an O-atom-bridged calix[2]naphthalene-[2]triazine synthesized using a one-pot approach from naphthalene-2,7-diol and cyanuric chloride, the two isolated naphthalene planes and the two triazine-2,6-di-oxy planes adopt a 1,3-alternate configuration, with a dihedral angle of 84.10 (8)° between the naphthalene rings and a dihedral angle of 39.02 (14)° between the triazine rings. In the crystal, weak inter-molecular π-π stacking inter-actions are found between face-to-face naphthalene rings [centroid-centroid distance = 3.662 (7) Å].

  2. Preparation and thermoelectric properties of Bi2Te2.7Se0.3 nanocomposites

    NASA Astrophysics Data System (ADS)

    Kim, Il-Ho; Choi, Soon-Mok; Seo, Won-Seon; Cheong, Dong-Ik

    2012-11-01

    Cu- or Ag-dispersed Bi2Te2.7Se0.3 nanocomposites were prepared by using metal-acetate decomposition and hot pressing. Cu or Ag nanoparticles were well-dispersed in the Bi2Te2.7Se0.3 matrix, and thereby the power factor was greatly increased due to the increase in the effective mass of a carrier. However, Cu or Ag dispersion did not affect the carrier concentration and could not reduce the lattice thermal conductivity because Cu or Ag nanoparticles did not act as phonon scattering centers effectively. The thermoelectric figure of merit was enhanced remarkably over a wide temperature range of 323-523 K due to the high power factor. Compared to Ag dispersion, Cu dispersion was much more effective in enhancing the thermoelectric performance.

  3. Sm4S3Si2O7

    NASA Astrophysics Data System (ADS)

    Villars, P.; Cenzual, K.; Daams, J.; Gladyshevskii, R.; Shcherban, O.; Dubenskyy, V.; Kuprysyuk, V.; Savysyuk, I.

    This document is part of Subvolume A9 `Structure Types. Part 9: Space Groups (148) R-3 - (141) I41' of Volume 43 `Crystal Structures of Inorganic Compounds' of Landolt-Börnstein - Group III `Condensed Matter'.

  4. 40 CFR 721.5279 - 2,7-Naphthalenedisulfonic acid, 4-amino-3-[[4′2-amino-4-[(3-butoxy-2-hydroxypropyl)amino]phebyl...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Substances § 721.5279 2,7-Naphthalenedisulfonic acid, 4-amino-3- phebyl]azo]-3,3′-dimethyl -4-yl]azo]-5... reporting. (1) The chemical substance identified as 2,7-naphthalenedisulfonic acid, 4-amino-3- phebyl]azo]-3... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 2,7-Naphthalenedisulfonic acid,...

  5. 40 CFR 721.5279 - 2,7-Naphthalenedisulfonic acid, 4-amino-3-[[4′2-amino-4-[(3-butoxy-2-hydroxypropyl)amino]phebyl...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Substances § 721.5279 2,7-Naphthalenedisulfonic acid, 4-amino-3- phebyl]azo]-3,3′-dimethyl -4-yl]azo]-5... reporting. (1) The chemical substance identified as 2,7-naphthalenedisulfonic acid, 4-amino-3- phebyl]azo]-3... 40 Protection of Environment 31 2011-07-01 2011-07-01 false 2,7-Naphthalenedisulfonic acid,...

  6. 40 CFR 721.5279 - 2,7-Naphthalenedisulfonic acid, 4-amino-3-[[4′2-amino-4-[(3-butoxy-2-hydroxypropyl)amino]phebyl...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Substances § 721.5279 2,7-Naphthalenedisulfonic acid, 4-amino-3- phebyl]azo]-3,3′-dimethyl -4-yl]azo]-5... reporting. (1) The chemical substance identified as 2,7-naphthalenedisulfonic acid, 4-amino-3- phebyl]azo]-3... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 2,7-Naphthalenedisulfonic acid,...

  7. 40 CFR 721.5279 - 2,7-Naphthalenedisulfonic acid, 4-amino-3-[[4′2-amino-4-[(3-butoxy-2-hydroxypropyl)amino]phebyl...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Substances § 721.5279 2,7-Naphthalenedisulfonic acid, 4-amino-3- phebyl]azo]-3,3′-dimethyl -4-yl]azo]-5... reporting. (1) The chemical substance identified as 2,7-naphthalenedisulfonic acid, 4-amino-3- phebyl]azo]-3... 40 Protection of Environment 32 2012-07-01 2012-07-01 false 2,7-Naphthalenedisulfonic acid,...

  8. 40 CFR 721.5279 - 2,7-Naphthalenedisulfonic acid, 4-amino-3-[[4′2-amino-4-[(3-butoxy-2-hydroxypropyl)amino]phebyl...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Substances § 721.5279 2,7-Naphthalenedisulfonic acid, 4-amino-3- phebyl]azo]-3,3′-dimethyl -4-yl]azo]-5... reporting. (1) The chemical substance identified as 2,7-naphthalenedisulfonic acid, 4-amino-3- phebyl]azo]-3... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 2,7-Naphthalenedisulfonic acid,...

  9. Expression of purinergic P2X receptor subtypes 1, 2, 3 and 7 in equine laminitis.

    PubMed

    Zamboulis, Danae E; Senior, Mark; Clegg, Peter D; Milner, Peter I

    2013-11-01

    Tissue sensitisation and chronic pain have been described in chronic-active laminitis in the horse, making treatment of such cases difficult. Purinergic P2X receptors are linked to chronic pain and inflammation. The aim of this study was to examine the expression of purinergic P2X receptor subtypes 1, 2, 3 and 7 in the hoof, palmar digital vessels and nerve, dorsal root ganglia and spinal cord in horses with chronic-active laminitis (n=5) compared to non-laminitic horses (n=5). Immunohistochemical analysis was performed on tissue sections using antibodies against P2X receptor subtypes 1-3 and 7. In horses with laminitis, there was a reduction in the thickness of the tunica media layer of the palmar digital vein as a proportion of the whole vessel diameter (0.48±0.05) compared to the non-laminitic group (0.57±0.04; P=0.02). P2X receptor subtype 3 was expressed in the smooth muscle layer (tunica media) of the palmar digital artery of horses with laminitis, but was absent in horses without laminitis. There was strong expression of P2X receptor subtype 7 in the proliferating, partially keratinised, epidermal cells of the secondary epidermal lamellae in the hooves of horses with laminitis, but no immunopositivity in horses without laminitis.

  10. Fragrance material review on 2-(3,7-dimethyl-2,6-octadienyl)cyclopentanone.

    PubMed

    Scognamiglio, J; Jones, L; Letizia, C S; Api, A M

    2012-10-01

    A toxicologic and dermatologic review of 2-(3,7-dimethyl-2,6-octadienyl)cyclopentanone when used as a fragrance ingredient is presented. 2-(3,7-Dimethyl-2,6-octadienyl)cyclopentanone is a member of the fragrance structural group Ketones Cyclopentanones and Cyclopentenones. The common characteristic structural element of the group members is a cyclopentanone or cyclopentenone ring with a straight or branched chain alkane or alkene substituent. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 2-(3,7-dimethyl-2,6-octadienyl)cyclopentanone were evaluated then summarized and includes physical properties, acute toxicity, skin irritation, and skin sensitization data. A safety assessment of the entire Ketones Cyclopentanones and Cyclopentenones will be published simultaneously with this document; please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all Ketones Cyclopentanones and Cyclopentenones in fragrances.

  11. C3H7NO2 β-Alanine

    NASA Astrophysics Data System (ADS)

    Demaison, J.

    This document is part of Part 2 of Subvolume D 'Asymmetric Top Molecules' of Volume 29 'Molecular Constants Mostly from Microwave, Molecular Beam, and Sub-Doppler Laser Spectroscopy' of Landolt-Börnstein - Group II 'Molecules and Radicals'.

  12. Involvement of the P2X7-NLRP3 axis in leukemic cell proliferation and death

    PubMed Central

    Salaro, Erica; Rambaldi, Alessia; Falzoni, Simonetta; Amoroso, Francesca Saveria; Franceschini, Alessia; Sarti, Alba Clara; Bonora, Massimo; Cavazzini, Francesco; Rigolin, Gian Matteo; Ciccone, Maria; Audrito, Valentina; Deaglio, Silvia; Pelegrin, Pablo; Pinton, Paolo; Cuneo, Antonio; Di Virgilio, Francesco

    2016-01-01

    Lymphocyte growth and differentiation are modulated by extracellular nucleotides and P2 receptors. We previously showed that the P2X7 receptor (P2X7R or P2RX7) is overexpressed in circulating lymphocytes from chronic lymphocytic leukemia (CLL) patients. In the present study we investigated the P2X7R/NLRP3 inflammasome axis in lymphocytes from a cohort of 23 CLL patients. P2X7R, ASC and NLRP3 were investigated by Western blot, PCR and transfection techniques. P2X7R was overexpressed and correlated with chromosome 12 trisomy in CLL patients. ASC mRNA and protein were also overexpressed. On the contrary, NLRP3 was dramatically down-modulated in CLL lymphocytes relative to lymphocytes from healthy donors. To further investigate the correlation between P2X7R, NLRP3 and cell growth, NLRP3 was silenced in THP-1 cells, a leukemic cell line that natively expresses both NLRP3 and P2X7R. NLRP3 silencing enhanced P2X7R expression and promoted growth. On the contrary, NLRP3 overexpression caused accelerated apoptosis. The P2X7R was also up-modulated in hematopoietic cells from NLRP3-KO mice. In conclusion, we show that NLRP3 down-modulation stimulates P2X7R expression and promotes growth, while NLRP3 overexpression inhibits cell proliferation and stimulates apoptosis. These findings suggest that NLRP3 is a negative regulator of growth and point to a role of the P2X7R/NLRP3 axis in CLL. PMID:27221966

  13. Involvement of the P2X7-NLRP3 axis in leukemic cell proliferation and death.

    PubMed

    Salaro, Erica; Rambaldi, Alessia; Falzoni, Simonetta; Amoroso, Francesca Saveria; Franceschini, Alessia; Sarti, Alba Clara; Bonora, Massimo; Cavazzini, Francesco; Rigolin, Gian Matteo; Ciccone, Maria; Audrito, Valentina; Deaglio, Silvia; Pelegrin, Pablo; Pinton, Paolo; Cuneo, Antonio; Di Virgilio, Francesco

    2016-01-01

    Lymphocyte growth and differentiation are modulated by extracellular nucleotides and P2 receptors. We previously showed that the P2X7 receptor (P2X7R or P2RX7) is overexpressed in circulating lymphocytes from chronic lymphocytic leukemia (CLL) patients. In the present study we investigated the P2X7R/NLRP3 inflammasome axis in lymphocytes from a cohort of 23 CLL patients. P2X7R, ASC and NLRP3 were investigated by Western blot, PCR and transfection techniques. P2X7R was overexpressed and correlated with chromosome 12 trisomy in CLL patients. ASC mRNA and protein were also overexpressed. On the contrary, NLRP3 was dramatically down-modulated in CLL lymphocytes relative to lymphocytes from healthy donors. To further investigate the correlation between P2X7R, NLRP3 and cell growth, NLRP3 was silenced in THP-1 cells, a leukemic cell line that natively expresses both NLRP3 and P2X7R. NLRP3 silencing enhanced P2X7R expression and promoted growth. On the contrary, NLRP3 overexpression caused accelerated apoptosis. The P2X7R was also up-modulated in hematopoietic cells from NLRP3-KO mice. In conclusion, we show that NLRP3 down-modulation stimulates P2X7R expression and promotes growth, while NLRP3 overexpression inhibits cell proliferation and stimulates apoptosis. These findings suggest that NLRP3 is a negative regulator of growth and point to a role of the P2X7R/NLRP3 axis in CLL. PMID:27221966

  14. Preparation of 7-hydroxy-2-oxoindolin-3-ylacetic acid and its [13C2], [5-n-3H], and [5-n-3H]-7-O-glucosyl analogues for use in the study of indol-3-ylacetic acid catabolism

    NASA Technical Reports Server (NTRS)

    Lewer, P.; Bandurski, R. S. (Principal Investigator)

    1987-01-01

    An improved synthesis of 7-hydroxy-2-oxoindolin-3-ylacetic acid via the base-induced condensation reaction between oxalate esters and 7-benzyloxyindolin-2-one is described. 7-Benzyloxyindolin-2-one was prepared in four steps and 50% overall yield from 3-hydroxy-2-nitrotoluene. The yield of the title compound from 7-benzyloxyindolin-2-one was 56%. This route was used to prepare 7-hydroxy-2-oxoindolin-3-yl[13C2]acetic acid in 30% yield from [13C2]oxalic acid dihydrate. The method could not be extended to the preparation of the corresponding [14C2]-compound. However, an enzyme preparation from Zea mays roots catalysed the conversion of carrier-free [5-n-3H]indol-3-ylacetic acid with a specific activity of 16.7 Ci mmol-1 to a mixture of 7-hydroxy-2-oxo[5-n-3H]indolin-3-ylacetic acid and its [5-n-3H]-7-O-glucoside in ca. 3 and 40% radiochemical yield respectively. The glucoside was converted into the 7-hydroxy compound in 80% yield by means of beta-glucosidase.

  15. Apically Linked Small Metallacarborane Clusters. Directed Synthesis and Structural Characterization of 7,7'-[CpCo(2,3-Et(2)C(2)B(4)H(3)](2) and [CpCo(2,3-Et(2)C(2)B(4)H(3)-7)](2)X Complexes (X = MeCH, HC=CH, C&tbd1;C)(,)(1).

    PubMed

    Curtis, Michael A.; Müller, Thomas; Beez, Volker; Pritzkow, Hans; Siebert, Walter; Grimes, Russell N.

    1997-08-13

    A series of novel bis(cobaltacarboranyl) (CoC(2)B(4))(2)X dicluster complexes whose B(7) (apex) atoms are linked by organic moieties involving sp-, sp(2)-, or sp(3)-hybridized carbon, or by a direct B(7)-B(7') bond, has been prepared by extension of the recently described "recapitation" method (Curtis, M. A.; et al. Inorg. Chem. 1996, 35, 6703) that entails treatment of 6-vertex nido-CoC(2)B(3) dianions with monoboron reagents. Reactions of Li(2)[nido-CpCo(Et(2)C(2)B(3)H(3))] in toluene with MeCH(BCl(2))(2) and with cis-(BCl(2))C(2)H(2) gave, respectively, [CpCo(2,3-Et(2)C(2)B(4)H(3)-7-)](2)MeCH (5) and cis-[CpCo(2,3-Et(2)C(2)B(4)H(3)-7-)](2)C(2)H(2) (6a) following chromatographic separation. Ultraviolet irradiation of 6a induced partial conversion to the trans isomer 6b, affording a 46:54 trans/cis equilibrium mixture in 84 h. Reactions of the same cobaltacarborane dianion with bis(catecholboryl)acetylene and with bis(catecholdiboryl) gave [CpCo(2,3-Et(2)C(2)B(4)H(3)-7-)](2)C(2) (7) and [CpCo(2,3-Et(2)C(2)B(4)H(3)-7-)](2) (8), respectively. The new complexes were isolated as air-stable, crystalline orange solids and were characterized from their (1)H, (11)B, and (13)C NMR, IR, UV-visible, and mass spectra, supported by X-ray crystallographic studies of 5, 6a, 7, and 8. Crystal data for 5: space group P2(1)ca (orthorhombic); a = 14.220(10) Å, b = 15.690(10) Å, c = 16.860(10) Å, Z = 4; R = 0.041 for 7485 independent reflections. Crystal data for 6a: space group C2/c (monoclinic); a = 12.849(6) Å, b = 11.435(6) Å, c = 25.619(13) Å, beta = 96.230(10) degrees; Z = 4; R = 0.036 for 5440 independent reflections. Crystal data for 7: space group P2(1)/n (monoclinic); a = 17.298(12) Å, b = 13.932(10) Å, c = 30.82(2) Å, beta = 96.34(5) degrees; Z = 8; R = 0.070 for 9632 independent reflections. Crystal data for 8: space group P&onemacr; (triclinic); a = 9.150(10) Å, b = 10.270(10) Å, c = 10.340(10) Å, alpha = 84.52(5) degrees, beta = 78.05(5) degrees, gamma = 68

  16. Ab initio study of Z2 topological phases in perovskite (111) (SrTiO3)7/(SrIrO3)2 and (KTaO3)7/(KPtO3)2 multilayers

    NASA Astrophysics Data System (ADS)

    Lado, J. L.; Pardo, V.; Baldomir, D.

    2013-10-01

    Honeycomb structures formed by the growth of perovskite 5d transition metal oxide heterostructures along the (111) direction in a t2g5 configuration can give rise to topological ground states characterized by a topological index ν=1, as reported by Xiao [Nat. Commun.2041-172310.1038/ncomms1602 2, 596 (2011)]. Using a combination of a tight binding model and ab initio calculations we study the multilayers (SrTiO3)7/(SrIrO3)2 and (KTaO3)7/(KPtO3)2 as a function of parity asymmetry, on-site interaction U, and uniaxial strain and determine the nature and evolution of the gap. According to our density functional theory calculations, (SrTiO3)7/(SrIrO3)2 is found to be a topological semimetal whereas (KTaO3)7/(KPtO3)2 is found to present a topological insulating phase that can be understood as the high U limit of the previous one, that can be driven to a trivial insulating phase by a perpendicular external electric field.

  17. Symmetric interfacial reconstruction and magnetism in La0.7Ca0.3MnO3/YBa2Cu3O7/La0.7Ca0.3MnO3 heterostructures

    SciTech Connect

    Visani, C.; Tornos, J.; Nemes, Norbert; Rocci, M.; Leon, C.; Santamaria, J.; te Velthuis, G. E.; Liu, Y.; Hoffman, A.; Freeland, J. W.; Garcia-Hernandez, M; Fitzsimmons, M. R.; Kirby, B. J.; Varela del Arco, Maria; Pennycook, Stephen J

    2011-01-01

    We have analyzed the interface structure and composition of La{sub 0.7}Ca{sub 0.3}MnO{sub 3}/YBa{sub 2}Cu{sub 3}O{sub 7}/La{sub 0.7}Ca{sub 0.3}MnO{sub 3} trilayers by combined polarized neutron reflectometry, aberration-corrected microscopy, and atomic column resolution electron-energy-loss spectroscopy and x-ray absorption with polarization analysis. We find the same stacking sequence at both top and bottom cuprate interfaces. X-ray magnetic circular dichroism experiments show that both cuprate interfaces are magnetic with a magnetic moment induced in Cu atoms as expected from symmetric Mn-O-Cu superexchange paths. These results supply a solid footing for the applicability of recent theories explaining the interplay between magnetism and superconductivity in this system in terms of the induced Cu spin polarization at both interfaces.

  18. Synthesis and antifungal activity of 7-methyl-7-hydroxy-2,3-benzo[c]octa-1,6-olide.

    PubMed

    Zhao, Jin; Dong, Hong-Bo; Yang, Ming-Yan; Du, Juan; Jiang, Jia-Zheng; Wang, Ming-An

    2014-01-01

    The racemic 7-methyl-7-hydroxy-2,3-benzo[c]octa-1,6-olide, the analog of natural product (6R)-3,7-dimethyl-7-hydroxy-2-octen-1,6-olide, was totally synthesized using easily available (E)-2-(2-carboxyvinyl)benzoic acid as a raw material in nine-step reactions including three key steps of Wittig reaction, epoxidation, and cyclization, with an overall yield of 10.3%. The bioassay results showed that ( ± )-2 exhibited stronger antifungal activity than the natural product ( ± )-1 and (R)-1 against Alternaria solani with an EC₅₀ value of 27.36 μg/ml. PMID:24456253

  19. Mott Physics in lightly doped (Sr1-xLax)3Ir2O7

    NASA Astrophysics Data System (ADS)

    Affeldt, Gregory; Hogan, Tom; Smallwood, Christopher; Das, Tanmoy; Denlinger, Jonathan; Mo, Sung-Kwan; Wilson, Stephen; Lanzara, Alessandra

    The layered perovskite iridates Sr2IrO4 and Sr3Ir2O7 exhibit a spin-orbit Mott insulating state that becomes metallic upon sufficient carrier doping. While Sr2IrO4 presents striking similarities to cuprates upon electron doping, Sr3Ir2O7 appears to be a correlated metal. We show a detailed doping and temperature-dependent ARPES study which reveals important similarities between (Sr1-xLax)3Ir2O7 and doped Sr2IrO4, as well as other doped Mott insulators.

  20. Bioavailability of 2,3,7,8-TCDD, 2,3,7,8-TCDF and PCBs to marine benthos from passaic river sediments

    SciTech Connect

    Rubinstein, N.I.; Pruell, R.J.; Taplin, B.K.; LiVolsi, J.A.; Norwood, C.B.

    1990-01-01

    The bioaccumulation and depuration of 2,3,7,8-tetrachlorodibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzofuran and polychlorinated biphenyls by marine benthos exposed to environmentally contaminated sediment were measured in a laboratory study. Sandworms (Nereis virens), clams (Macoma nasuta) and shrimp (Palaemonetes pugio) were exposed to sediment from the Passaic River, New Jersey for up to 180 days. Worms accumulated the highest concentrations of these compounds. Uptake and depuration rates were slowest in the worms and most rapid in the clams.

  1. Switching of saturation magnetization by carrier injection in YBa2Cu3O7-δ/α-Fe2O3/Nb-SrTiO3 junctions

    NASA Astrophysics Data System (ADS)

    Chen, Yuansha; Lian, Guijun; Xiong, Guangcheng; Venkatesan, T.

    2011-06-01

    Ferromagnetic (FM) α-Fe2O3 layers were deposited on n-type oxide semiconductor substrates of Nb-doped SrTiO3 (NSTO) to form YBa2Cu3O7-δ/α-Fe2O3/NSTO junctions. Multilevel resistance switching behavior was observed in YBa2Cu3O7-δ/α-Fe2O3/NSTO junctions with stable resistive states. The saturation magnetization MS of the YBa2Cu3O7-δ/α-Fe2O3/NSTO junctions was modulated by carrier injection and correlated with the conductivity of the switched state. This is the first report of simultaneous modulation of intrinsic magnetic and transport properties for FM oxide devices by using carrier injection.

  2. Characterization of the Ag/YBa2Cu3O(7-x) contact in thin films

    NASA Astrophysics Data System (ADS)

    Jia, Q. X.; Anderson, W. A.; Zheng, J. P.; Zhu, Y. Z.; Patel, S.

    1990-12-01

    Ag contacts to very thin superconducting YBa2Cu3O(7-x) films were prepared by thermal evaporation. The nature of the Ag/YBa2Cu3O(7-x) contact during thermal treatment was in situ investigated by a combination of three- and four-terminal resistance measurements. The experimental results suggested that the interaction between Ag and the YBa2Cu3O(7-x) film began at a temperature of around 370 C. The lack of reproducibility in forming a low-resistance contact to very thin YBa2Cu3O(7-x) films and the high probability of degrading the film quality after thermal treatment of the contact might be due to the excess Ag doping in YBa2Cu3O(7-x). Ag island formation, as revealed by SEM after thermal treatment of the contact, is a limitation of Ag for use as a good contact electrode for very thin superconducting films.

  3. Oxidation of indole-3-acetic acid and oxindole-3-acetic acid to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glucopyranoside in Zea mays seedlings

    NASA Technical Reports Server (NTRS)

    Nonhebel, H. M.; Bandurski, R. S.

    1984-01-01

    Radiolabeled oxindole-3-acetic acid was metabolized by roots, shoots, and caryopses of dark grown Zea mays seedlings to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glycopyranoside with the simpler name of 7-hydroxyoxindole-3-acetic acid-glucoside. This compound was also formed from labeled indole-3-acetic acid supplied to intact seedlings and root segments. The glucoside of 7-hydroxyoxindole-3-acetic acid was also isolated as an endogenous compound in the caryopses and shoots of 4-day-old seedlings. It accumulates to a level of 4.8 nanomoles per plant in the kernel, more than 10 times the amount of oxindole-3-acetic acid. In the shoot it is present at levels comparable to that of oxindole-3-acetic acid and indole-3-acetic acid (62 picomoles per shoot). We conclude that 7-hydroxyoxindole-3-acetic acid-glucoside is a natural metabolite of indole-3-acetic acid in Z. mays seedlings. From the data presented in this paper and in previous work, we propose the following route as the principal catabolic pathway for indole-3-acetic acid in Zea seedlings: Indole-3-acetic acid --> Oxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid-glucoside.

  4. Induced Ferromagnetism at BiFeO3/YBa2Cu3O7 Interfaces

    DOE PAGES

    Zhu, Jian-Xin; Wen, Xiao-Dong; Haraldsen, J. T.; He, Mi; Panagopoulos, C.; Chia, Elbert E. M.

    2014-06-20

    We report that transition metal oxides (TMOs) exhibit many emergent phenomena ranging from high-temperature superconductivity and giant magnetoresistance to magnetism and ferroelectricity. In addition, when TMOs are interfaced with each other, new functionalities can arise, which are absent in individual components. Here, we report results from first-principles calculations on the magnetism at the BiFeO3/YBa2Cu3O7 interfaces. By comparing the total energy for various magnetic spin configurations inside BiFeO3, we are able to show that a metallic ferromagnetism is induced near the interface. We further develop an interface exchange-coupling model and place the extracted exchange coupling interaction strengths, from the first-principles calculations,more » into a resultant generic phase diagram. Our conclusion of interfacial ferromagnetism is confirmed by the presence of a hysteresis loop in field-dependent magnetization data. Lastly, the emergence of interfacial ferromagnetism should have implications to electronic and transport properties.« less

  5. A new Sb-based polysulfide: Ba3Sb2S7 containing (S2)2- ligand

    NASA Astrophysics Data System (ADS)

    Geng, Lei; Luo, Zhong-Zhen; Cheng, Wen-Dan

    2013-09-01

    A new ternary sulfide Ba3Sb2S7 was synthesized from high temperature solid-state reactions in a flame-sealed silica ampoule. It crystallizes in the C2/c space group of the monoclinic system with a = 18.380(2) Å, b = 12.266(2) Å, c = 13.164(2) Å, β = 110.054(6)°, V = 2788.0(7) Å3, and Z = 8. The compound features an interesting zero-dimensional structure built of two types of isolated SbS3 and SbS2(S2) units surrounded with the charge balanced Ba2+ cations. The UV-Vis-NIR optical diffuse reflectance measurements along with the electronic band structure calculations indicate that Ba3Sb2S7 belongs to an indirect semiconductor with the band gap of 2.4 eV. Electronic density of states (DOS) analyses were also performed to interpret the intrinsic behavior of charge transfers in the SbS3 and SbS2(S2) units, respectively.

  6. 40 CFR 721.5500 - 7-Oxabicyclo[4.1.0]heptane, 3-ethenyl, homopolymer, ether with 2-ethyl-2-(hydroxymethyl)-1,3-pro...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., homopolymer, ether with 2-ethyl-2-(hydroxymethyl)-1,3-pro-pane-diol (3:1), epoxidized. 721.5500 Section 721...-Oxabicyclo heptane, 3-ethenyl, homopolymer, ether with 2-ethyl-2-(hydroxymethyl)-1,3-pro-pane-diol (3:1... 7-oxabicyclo heptane, 3-ethenyl, homopolymer, ether with 2-ethyl-2(hydroxymethyl)-1,3-propanediol...

  7. 40 CFR 721.5500 - 7-Oxabicyclo[4.1.0]heptane, 3-ethenyl, homopolymer, ether with 2-ethyl-2-(hydroxymethyl)-1,3-pro...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., homopolymer, ether with 2-ethyl-2-(hydroxymethyl)-1,3-pro-pane-diol (3:1), epoxidized. 721.5500 Section 721...-Oxabicyclo heptane, 3-ethenyl, homopolymer, ether with 2-ethyl-2-(hydroxymethyl)-1,3-pro-pane-diol (3:1... 7-oxabicyclo heptane, 3-ethenyl, homopolymer, ether with 2-ethyl-2(hydroxymethyl)-1,3-propanediol...

  8. Sensitizing effect of Ho3+ on the Er3+: 2.7 μm-emission in fluoride glass

    NASA Astrophysics Data System (ADS)

    Huang, Feifei; Li, Xia; Liu, Xueqiang; Zhang, Junjie; Hu, Lili; Chen, Danping

    2014-03-01

    The fluorescence properties of 2.7 μm emission and energy transfer mechanism of Ho3+/Er3+ co-doped fluoride glass (ZBYA) have been investigated in the present paper. Ho3+ strengthens the Er3+: 2.7 μm emission in the ZBYA glasses due to the energy transfer from Er3+ to Ho3+, while the 1.5 μm emission decreases dramatically. The optimized concentration ratio of Er3+ to Ho3+ is found to be 1:1 in our glass system. The absorption and emission spectra are tested and the sample possesses large emission cross section (16.5 × 10-21 cm2) around 2.7 μm along with larger radiative transition probability (25.11 S-1) on the basis of Judd-Ofelt and Fuchtbauer-Ladenburg theories. Additionally, the energy transfer microparameters are calculated using Förster-Dexter theory and the result shows the energy transfer coefficient of Er3+:4I13/2 → Ho3+:5I7 is 24 times larger than that of Er3+:4I11/2 → Ho3+:5I6. Our results show that Er3+: 2.7 μm emission can be sensitized by Ho3+ efficiently, and this Er3+/Ho3+-codoped fluoride glasses might have potential application in mid-infrared lasers.

  9. Synthesis of nanostructured materials based on YBa2Cu3O7_y and BiFeO3

    NASA Astrophysics Data System (ADS)

    Palchaev, D. K.; Murlieva, Zh Kh; Rabadanov, M. H.; Gadzhimagomedov, S. Kh; M-R Alikhanov, N.; Emirov, R. M.; Asvarov, A. S.

    2016-09-01

    Methods for creating new nanostructured materials based on YBa2Cu3O7-δ and BiFeO3, results of a study of their structure, morphology and electrical properties are present. Morphology studies show that the micron-sized grains of ceramics are agglomerates of nanoparticles of about 50 nm average size for both BiFeO3 and YBa2Cu3O7-y. These nanoparticles are responsible for weak ferromagnetism in bismuth ferrite, and for increase of the critical temperature up to 96 K in YBa2Cu3O7-δ nanoceramics.

  10. Pr3+-sensitized Er3+-doped bismuthate glass for generating high inversion rates at 2.7 µm wavelength.

    PubMed

    Guo, Yanyan; Tian, Ying; Zhang, Liyan; Hu, Lili; Chen, Nan-Kuang; Zhang, Junjie

    2012-08-15

    With a 980 nm laser diode pumping, the 2.7 µm emission and energy transfer processes of Er3+/Pr3+ codoped germanium-gallium-bismuthate glasses have been investigated. For Er3+ (1 mol. %) and Pr3+ (1 mol. %) molar concentrations, an intense 2.7 µm emission was obtained based on the high excited-state absorption of Er3+ ions and energy transfer (ET) between Er3+ and Pr3+ ions codopant (ET). The intrinsic lifetime of Er3+:4I(13/2) level is quenched effectively (from 6.85 ms down to 0.24 ms) and the population inversions between Er3+:4I(11/2) and 4I(13/2) levels are enhanced to achieve a four-level energy system at 2.7 µm.

  11. Magnetic hysteresis of p(+) and He-3(2+) irradiated melt-textured YBa2Cu3O(7-delta)

    NASA Technical Reports Server (NTRS)

    Song, S. N.; Liu, J.; Chen, I. G.; Weinstein, Roy

    1992-01-01

    We have measured the magnetic hysteresis loops and temperature dependent trapped fields in melt-textured YBa2Cu3O(7-delta) samples before and after p(+) and He-3(2+) irradiation using a Hall effect magnetometer (HEM) as well as a commercial vibrating sample magnetometer (VSM). For proper He-3(2+) fluence, the critical current density may be enhanced by a factor of 10. Calculations based on various critical state models show that before the irradiation, the hysteresis loops can be well accounted for by a critical current density of a modified power law field dependence. After the irradiation, the best fit has been achieved by using an exponential form. Jc and its field dependence deduced from HEM hysteresis loops are in good agreement with those deduced from the VSM loops, suggesting that the Hall effect magnetometer can be conveniently used to characterize bulk high Tc oxide superconductors.

  12. 40 CFR 721.10469 - 2-Propenoic acid, 2-ethyltricyclo[3.3.1.13,7]dec-2-yl ester.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for...)(i), (a)(2)(iii), (a)(3), (a)(4) (National Institute for Occupational Safety and Health...

  13. 40 CFR 721.10468 - 2-Propenoic acid, 2-methyltricyclo[3.3.1.13,7]dec-2-yl ester.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for...)(i), (a)(2)(iii), (a)(3), (a)(4) (National Institute for Occupational Safety and Health...

  14. Electron-impact excitation of the Rb 7 2S1/2, 8 2S1/2, 5 2D3/2, and 6 2D3/2 states

    NASA Astrophysics Data System (ADS)

    Wei, Zuyi; Flynn, Connor; Redd, Aaron; Stumpf, Bernhard

    1993-03-01

    Electron-impact cross sections for excitation of the 7 2S1/2, 8 2S1/2, 5 2D3/2, and 6 2D3/2 states of rubidium have been measured from threshold to 1000 eV. The optical-excitation-function method has been employed in a crossed atom- and electron-beam apparatus. Relative, total (cascade including) experimental cross sections are made absolute by comparison with the known total cross section of the Rb D1 line. Total excitation cross sections are compared with theoretical calculations employing first Born approximation and theoretical branching ratios. Born cross sections for the 7 2S1/2 and 8 2S1/2 states are obtained from the literature, while Born cross sections for the 5 2D3/2, 6 2D3/2, and all cascading states are calculated in this paper. At high energies, the measured total 2D3/2 state cross sections show 1/E behavior and converge to first Born theory; for E>100 eV, experiment and theory agree within 6.7% for 5 2D3/2 and within 3.7% for 6 2D3/2. The total cross sections for the 2S1/2 states do not converge to Born theory even at 1000 eV, and it is shown that this cannot be attributed to cascading. At low energies, 2S1/2 and 2D3/2 state total excitation cross sections have similar shapes with sharply peaked maxima at about 0.9 eV above threshold. After cascading is corrected using first Born theory, estimated experimental cross sections for direct excitation of higher fine-structure states of rubidium are given.

  15. Effects of 2,3,7,8-TCDD on the larvae of fathead minnows (Pimephales promelas)

    SciTech Connect

    Olivieri, C.E.; Cooper, K.R.

    1994-12-31

    This study evaluated the sensitivity of the fathead minnow larvae to 2,3,7,8-TCDD. There are no reported studies that have examined 2,3,7,8-TCDD toxic effects on fathead minnow larvae (0.0017--0.0094 g). One month old fathead minnow larvae were exposed to varying concentrations of [H{sup 3}]2,3,7,8-TCDD for 24h, and then were transferred into clean water. The no-treatment, acetone-control and 2,3,7,8-TCDD exposed larvae were observed for at least 32 days after exposure. Mortality, growth and appearance of a wasting-type syndrome were noted. The tissue dose were based on larvae wet weight. One hundred percent mortality was observed at a tissue dose of 163 ng/g at 32 days. The wasting-type syndrome appeared at day 7 after the 2,3,7,8-TCDD exposure. Statistically significant differences in growth (total length and weight) were observed at tissue doses as low as 20 ng/g. The wasting-type syndrome was observed in all fish by day 20. The 2,3,7,8-TCDD tissue level showing this effect was 44 ng/g. These results suggested that the fathead minnow larvae are more sensitive than the Japanese medaka larvae, and not as sensitive as the lake trout.

  16. Near-edge study of gold-substituted YBa2Cu3O(7-delta)

    NASA Technical Reports Server (NTRS)

    Ruckman, Mark W.; Hepp, Aloysius F.

    1991-01-01

    The valence of Cu and Au in YBa2Au0.3Cu2.7O7-delta was investigated using x-ray absorption near edge structure (XANES). X-ray and neutron diffraction studies indicate that Au goes on the Cu(1) site and Cu K-edge XANES shows that this has little effect on the oxidation state of the remaining copper. The Au L3 edge develops a white line feature whose position lies between that of trivalent gold oxide and monovalent potassium gold cyanide, and whose height relative to the edge step is smaller than in the two reference compounds. The appearance of the Au L3 edge suggests that fewer Au 3d states are involved in forming the Au-O bond in YBa2Au0.3Cu2.7O7-delta than in trivalent gold oxide.

  17. Near-edge study of gold-substituted YBa2Cu3O(7-delta)

    NASA Technical Reports Server (NTRS)

    Ruckman, Mark W.; Hepp, Aloysius F.

    1991-01-01

    The valence of Cu and Au in YBa2Au0.3Cu2.7O7-delta was investigated using X-ray absorption near edge structure (XANES). X-ray and neutron diffraction studies indicate that Au goes on the Cu(1) site and Cu K-edge XANES shows that this has little effect on the oxidation state of the remaining copper. The Au L3 edge develops a white line feature whose position lies between that of trivalent gold oxide and monovalent potassium gold cyanide, and whose height relative to the edge step is smaller than in the two reference compounds. The appearance of the Au L3 edge suggests that fewer Au 3d states are involved in forming the Au-O bond in YBa2Au0.3Cu2.7O7-delta than in trivalent gold oxide.

  18. [Zn 3+ xV 2- xO 7-3 x(OH) 2+3 x]ṡ2H 2O and M[Zn 3- xV 2O 7(OH) 2]Cl 1-2 xṡ( 1+2x)H 2O two families of zinc vanadates with structures related to the hexagonal structure of [Zn 3V 2O 7(OH) 2]ṡ2H 2O

    NASA Astrophysics Data System (ADS)

    Hoyos, Dora; Palacio, Luz Amparo; Paillaud, Jean-Louis; Simon-Masseron, Angélique; Guth, Jean-Louis

    2004-11-01

    [Zn 3+ xV 2- xO 7-3 x(OH) 2+3 x]ṡ2H 2O ( I), with 03- xV 2O 7(OH) 2]Cl 1-2 xṡ(1+2x)H 2O ( II), with 0.152; aV 2O 5; bMOH; 228H 2O, with M = Li, Na, NH 4 or K for ( I) and NH 4 or Rb for ( II); 0.23V 2O 7(OH) 2]ṡ2H 2O. Their Zn/V molar ratio can be determined from to the unit-cell parameter a by the linear relations Zn/V=4.896a-28.124 ( R=0.988) for ( I) and Zn/V=15.302a-91.027 (with R=0.992) for ( II). In ( I) the negative charges created by the substitution of vanadium with zinc in the tetrahedra of the pyrovanadate pillars connecting the octahedral sheets containing the zinc, are compensated by protonation of framework oxygen atoms. In ( II) the negative charges, created by the removal of zinc in the octahedral sheet, are compensated by cations ( NH4+ or Rb +) located between the pyrovanadate pillars. But in order to fill more completely the space, additional cations ( NH4+ or Rb +) are incorporated in form of the chloride salt.

  19. Discovery and Structure–Activity Relationship of Novel 2,3-Dihydrobenzofuran-7-carboxamide and 2,3-Dihydrobenzofuran-3(2H)-one-7-carboxamide Derivatives as Poly(ADP-ribose)polymerase-1 Inhibitors

    PubMed Central

    2015-01-01

    Novel substituted 2,3-dihydrobenzofuran-7-carboxamide (DHBF-7-carboxamide) and 2,3-dihydrobenzofuran-3(2H)-one-7-carboxamide (DHBF-3-one-7-carboxamide) derivatives were synthesized and evaluated as inhibitors of poly(ADP-ribose)polymerase-1 (PARP-1). A structure-based design strategy resulted in lead compound 3 (DHBF-7-carboxamide; IC50 = 9.45 μM). To facilitate synthetically feasible derivatives, an alternative core was designed, DHBF-3-one-7-carboxamide (36, IC50 = 16.2 μM). The electrophilic 2-position of this scaffold was accessible for extended modifications. Substituted benzylidene derivatives at the 2-position were found to be the most potent, with 3′,4′-dihydroxybenzylidene 58 (IC50 = 0.531 μM) showing a 30-fold improvement in potency. Various heterocycles attached at the 4′-hydroxyl/4′-amino of the benzylidene moiety resulted in significant improvement in inhibition of PARP-1 activity (e.g., compounds 66–68, 70, 72, and 73; IC50 values from 0.718 to 0.079 μM). Compound 66 showed selective cytotoxicity in BRCA2-deficient DT40 cells. Crystal structures of three inhibitors (compounds (−)-13c, 59, and 65) bound to a multidomain PARP-1 structure were obtained, providing insights into further development of these inhibitors. PMID:24922587

  20. β-K3Fe(MoO4)2Mo2O7

    PubMed Central

    Souilem, Amira; Zid, Mohamed Faouzi; Driss, Ahmed

    2014-01-01

    The title compound, tripotassium iron(III) bis­(ortho­molyb­date) dimolybdate, was obtained by a solid-state reaction. The main structural building units are one FeO6 octa­hedron, two MoO4 tetra­hedra and one Mo2O7 dimolybdate group, all with point group symmetries m. These units are linked via corner-sharing to form ribbons parallel to [010]. The three K+ cations are located between the ribbons on mirror planes and have coordination numbers of 10 and 12. Two O atoms of one of the MoO4 tetra­hedra of the dimolybdate group are disordered over two positions in a 0.524 (11):0.476 (11) ratio. The structure of the title compound is compared briefly with that of Rb3FeMo4O15. PMID:25161509

  1. Structural Investigation of (U0.7Pu0.3)O2-x Mixed Oxides.

    PubMed

    Vigier, Jean-François; Martin, Philippe M; Martel, Laura; Prieur, Damien; Scheinost, Andreas C; Somers, Joseph

    2015-06-01

    Uranium-plutonium mixed oxide containing 30% of plutonium is a candidate fuel for several fast neutron and accelerator driven reactor systems. In this work, a detailed structural investigation on sol-gel synthesized stoichiometric U0.7Pu0.3O2.00 and substoichiometric U0.7Pu0.3O2-x, using X-ray diffraction (XRD), oxygen 17 magic angle spinning nuclear magnetic resonance ((17)O MAS NMR) and X-ray absorption spectroscopy is described. As observed by XRD, the stoichiometric U0.7Pu0.3O2.00 is monophasic with a lattice parameter in good agreement with Vegard's law, while the substoichiometric U0.7Pu0.3O2-x material is biphasic. Solid solution ideality in terms of a random distribution of metal atoms is proven for U0.7Pu0.3O2.00 with (17)O MAS NMR. X-ray absorption near-edge structure (XANES) spectroscopy shows the presence of plutonium(III) in U0.7Pu0.3O2-x. Extended X-ray absorption fine-structure (EXAFS) spectroscopy indicates a similar local structure around both cations, and comparison with XRD indicates a close similarity between uranium and plutonium local structures and the long-range ordering. PMID:25984750

  2. Structural Investigation of (U0.7Pu0.3)O2-x Mixed Oxides.

    PubMed

    Vigier, Jean-François; Martin, Philippe M; Martel, Laura; Prieur, Damien; Scheinost, Andreas C; Somers, Joseph

    2015-06-01

    Uranium-plutonium mixed oxide containing 30% of plutonium is a candidate fuel for several fast neutron and accelerator driven reactor systems. In this work, a detailed structural investigation on sol-gel synthesized stoichiometric U0.7Pu0.3O2.00 and substoichiometric U0.7Pu0.3O2-x, using X-ray diffraction (XRD), oxygen 17 magic angle spinning nuclear magnetic resonance ((17)O MAS NMR) and X-ray absorption spectroscopy is described. As observed by XRD, the stoichiometric U0.7Pu0.3O2.00 is monophasic with a lattice parameter in good agreement with Vegard's law, while the substoichiometric U0.7Pu0.3O2-x material is biphasic. Solid solution ideality in terms of a random distribution of metal atoms is proven for U0.7Pu0.3O2.00 with (17)O MAS NMR. X-ray absorption near-edge structure (XANES) spectroscopy shows the presence of plutonium(III) in U0.7Pu0.3O2-x. Extended X-ray absorption fine-structure (EXAFS) spectroscopy indicates a similar local structure around both cations, and comparison with XRD indicates a close similarity between uranium and plutonium local structures and the long-range ordering.

  3. Luminescent properties and characterization of Gd2O3:Eu3+@SiO2 and Gd2Ti2O7:Eu3+@SiO2 core shell phosphors prepared by a sol gel process

    NASA Astrophysics Data System (ADS)

    Lin, Kuo-Min; Lin, Chih-Cheng; Li, Yuan-Yao

    2006-03-01

    Gd2O3:Eu3+ and Gd2Ti2O7:Eu3+ films 10 nm in thickness were individually coated onto silica spheres (particle size of 150-170 nm) using the sol-gel method. The synthesized materials were addressed as Gd2O3:Eu3+@SiO2 and Gd2Ti2O7:Eu3+@SiO2 phosphors. An x-ray powder diffractometer (XRD), field emission scanning electron microscope (FE-SEM), high-resolution transmission electron microscope (HR-TEM), and photoluminescence spectrophotometer (PL) were employed to characterize the core-shell phosphors. Uniform core-shell phosphor particles were observed using FE-SEM. The XRD and HR-TEM results indicated that the coated-shell layer was well crystallized after sintering at 1000 °C. The Gd2O3:Eu3+@SiO2 PL measurement showed a red emission at the main 615 nm wavelength. The Gd2Ti2O7:Eu3+@SiO2 phosphor showed an orange-red emission at the 588 and 615 nm wavelengths. In comparison with the Gd2O3:Eu3+ and Gd2Ti2O7:Eu3+ bulk material results, the core-shell phosphors maintained the same emission ability as the bulk materials and the novel core-shell phosphors possessed great potential in quantum phosphor applications.

  4. Luminescent properties and characterization of Gd2O3:Eu(3+)@SiO2 and Gd2Ti2O7:Eu(3+)@SiO2 core-shell phosphors prepared by a sol-gel process.

    PubMed

    Lin, Kuo-Min; Lin, Chih-Cheng; Li, Yuan-Yao

    2006-03-28

    Gd2O3:Eu(3+) and Gd2Ti2O7:Eu(3+) films 10 nm in thickness were individually coated onto silica spheres (particle size of 150-170 nm) using the sol-gel method. The synthesized materials were addressed as Gd2O3:Eu(3+)@SiO2 and Gd2Ti2O7:Eu(3+)@SiO2 phosphors. An x-ray powder diffractometer (XRD), field emission scanning electron microscope (FE-SEM), high-resolution transmission electron microscope (HR-TEM), and photoluminescence spectrophotometer (PL) were employed to characterize the core-shell phosphors. Uniform core-shell phosphor particles were observed using FE-SEM. The XRD and HR-TEM results indicated that the coated-shell layer was well crystallized after sintering at 1000 °C. The Gd2O3:Eu(3+)@SiO2 PL measurement showed a red emission at the main 615 nm wavelength. The Gd2Ti2O7:Eu(3+)@SiO2 phosphor showed an orange-red emission at the 588 and 615 nm wavelengths. In comparison with the Gd2O3:Eu(3+) and Gd2Ti2O7:Eu(3+) bulk material results, the core-shell phosphors maintained the same emission ability as the bulk materials and the novel core-shell phosphors possessed great potential in quantum phosphor applications.

  5. Mechanism of Dis3L2 substrate recognition in the Lin28/let-7 pathway

    PubMed Central

    Joshua-Tor, Leemor

    2014-01-01

    Summary paragraph The pluripotency factor Lin28 inhibits the biogenesis of the let-7 family of mammalian microRNAs1–4. Lin28 is highly expressed in embryonic stem cells and has a fundamental role in regulation of development5, glucose metabolism6 and tissue regeneration7. Alternatively, Lin28 overexpression is correlated with the onset of numerous cancers8, while let-7, a tumor suppressor, silences several human oncogenes5. Lin28 binds to precursor let-7 (pre-let-7) hairpins9, triggering the 3' oligo-uridylation activity of TUT4/710–12. The oligoU tail added to pre-let-7 serves as a decay signal, as it is rapidly degraded by Dis3L213,14, a homolog of the catalytic subunit of the RNA exosome. The molecular basis of Lin28 mediated recruitment of TUT4/7 to pre-let-7 and its subsequent degradation by Dis3L2 is largely unknown. To examine the mechanism of Dis3L2 substrate recognition we determined the structure of mouse Dis3L2 in complex with an oligoU RNA to mimic the uridylated tail of pre-let-7. Three RNA binding domains form an open funnel on one face of the catalytic domain that allows RNA to navigate a path to the active site different from its exosome counterpart. The resulting path reveals an extensive network of uracil-specific interactions spanning the first twelve nucleotides of an oligoU-tailed RNA. We identify three U-specificity zones that explain how Dis3L2 recognizes, binds and processes uridylated pre-let-7 in the final step of the Lin28/let-7 pathway. PMID:25119025

  6. Studies on activation mechanism of a mitomycin dimer, 7-N,7'-N'-(1″,2″-dithiepanyl-3″,7″-dimethylenyl)bismitomycin C.

    PubMed

    Kim, Jae Jin; Kim, Hyoung Rae; Lee, Sang Hyup

    2012-09-01

    We report the studies on nucleophilic activation and DNA alkylation of a cyclic disulfide mitomycin dimer, 7-N,7'-N'-(1″,2″-dithiepanyl-3″,7″-dimethylenyl)bismitomycin C (6) along with a diol mitomycin dimer, 7-N,7'-N'-(2″,6″-dihydroxy-1″,7″-heptanediyl)bismitomycin C (7). We wished to see if disulfide mitomycin 6 undergoes efficient nucleophilic activation and corresponding formation of DNA interstrand cross-link (DNA ISC) products compared to diol mitomycin 7. Mitomycin 6 is a dimer connected by a seven-membered cyclic disulfide (a 1,2-dithiepane) linker, and mitomycin 7 is also a dimer containing 2,6-dihydroxyheptane linker that was employed as a reference one to identify the effect of disulfide unit in 6. Through kinetic studies using solvolysis reaction, we found that 6 underwent much faster nucleophilic activation by Et3P compared to 7, and that the enhanced activation rates were induced by the disulfide unit in 6. These findings led us to propose a nucleophilic activation mechanism for 6. We further demonstrated that 6 produced much higher levels of DNA ISC (86%) by the action of Et3P compared with 7 (5%) and 1 (4%). Therefore, we have concluded that 6 was highly efficient for nucleophilic activation and DNA ISC formation due to the key role of cyclic disulfide unit in 6.

  7. Optical spectroscopy and band gap analysis of hybrid improper ferroelectric Ca3Ti2O7

    NASA Astrophysics Data System (ADS)

    Cherian, Judy G.; Birol, Turan; Harms, Nathan C.; Gao, Bin; Cheong, Sang-Wook; Vanderbilt, David; Musfeldt, Janice L.

    2016-06-01

    We bring together optical absorption spectroscopy, photoconductivity, and first principles calculations to reveal the electronic structure of the room temperature ferroelectric Ca3Ti2O7. The 3.94 eV direct gap in Ca3Ti2O7 is charge transfer in nature and noticeably higher than that in CaTiO3 (3.4 eV), a finding that we attribute to dimensional confinement in the n = 2 member of the Ruddlesden-Popper series. While Sr substitution introduces disorder and broadens the gap edge slightly, oxygen deficiency reduces the gap to 3.7 eV and gives rise to a broad tail that persists to much lower energies.

  8. Candidate Quantum Spin Liquid in the Ce3+ Pyrochlore Stannate Ce2Sn2O7.

    PubMed

    Sibille, Romain; Lhotel, Elsa; Pomjakushin, Vladimir; Baines, Chris; Fennell, Tom; Kenzelmann, Michel

    2015-08-28

    We report the low-temperature magnetic properties of Ce2Sn2O7, a rare-earth pyrochlore. Our susceptibility and magnetization measurements show that due to the thermal isolation of a Kramers doublet ground state, Ce2Sn2O7 has Ising-like magnetic moments of ∼1.18  μ_{B}. The magnetic moments are confined to the local trigonal axes, as in a spin ice, but the exchange interactions are antiferromagnetic. Below 1 K, the system enters a regime with antiferromagnetic correlations. In contrast to predictions for classical ⟨111⟩-Ising spins on the pyrochlore lattice, there is no sign of long-range ordering down to 0.02 K. Our results suggest that Ce2Sn2O7 features an antiferromagnetic liquid ground state with strong quantum fluctuations. PMID:26371677

  9. Genetic and physical interaction of Meis2, Pax3 and Pax7 during dorsal midbrain development

    PubMed Central

    2012-01-01

    Background During early stages of brain development, secreted molecules, components of intracellular signaling pathways and transcriptional regulators act in positive and negative feed-back or feed-forward loops at the mid-hindbrain boundary. These genetic interactions are of central importance for the specification and subsequent development of the adjacent mid- and hindbrain. Much less, however, is known about the regulatory relationship and functional interaction of molecules that are expressed in the tectal anlage after tectal fate specification has taken place and tectal development has commenced. Results Here, we provide experimental evidence for reciprocal regulation and subsequent cooperation of the paired-type transcription factors Pax3, Pax7 and the TALE-homeodomain protein Meis2 in the tectal anlage. Using in ovo electroporation of the mesencephalic vesicle of chick embryos we show that (i) Pax3 and Pax7 mutually regulate each other's expression in the mesencephalic vesicle, (ii) Meis2 acts downstream of Pax3/7 and requires balanced expression levels of both proteins, and (iii) Meis2 physically interacts with Pax3 and Pax7. These results extend our previous observation that Meis2 cooperates with Otx2 in tectal development to include Pax3 and Pax7 as Meis2 interacting proteins in the tectal anlage. Conclusion The results described here suggest a model in which interdependent regulatory loops involving Pax3 and Pax7 in the dorsal mesencephalic vesicle modulate Meis2 expression. Physical interaction with Meis2 may then confer tectal specificity to a wide range of otherwise broadly expressed transcriptional regulators, including Otx2, Pax3 and Pax7. PMID:22390724

  10. Fractional precipitation synthesis and photoluminescence of La2Ti2O7:xEu3+ phosphors

    NASA Astrophysics Data System (ADS)

    Lian, Jingbao; He, Jiao; Zhang, Xue; Liu, Feng

    2016-11-01

    Eu3+ ions activated La2Ti2O7 (La2Ti2O7:xEu3+) phosphors have been successfully synthesized by a fractional precipitation method from commercially available La2O3, Eu2O3, HNO3, Ti(SO4)2·9H2O and NH3·H2O as the starting materials. Detailed characterizations of the synthetic products were obtained by fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), differential thermal analysis, thermogravimetry and derivative thermogravimetry (DTA-TG-DTG), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy. The results show that the precursor is composed of amorphous particles with quasi-spherical in shape and about 50 nm in size. Moreover, the precursor could be converted into pure La2Ti2O7 phase by calcining at 1000 °C for 2 h in air. The as-synthesized La2Ti2O7 particles are approximate polyhedron in shape and about 100-200 nm in size. PL spectroscopy of La2Ti2O7:xEu3+ phosphors reveals that the strongest emission peak is located at 616 nm under 275 nm ultraviolet (UV) light excitation, which corresponds to the 5D0→7F2 transition of Eu3+ ions. The quenching concentration of Eu3+ ions is 10.0 mol%, and its corresponding fluorescence lifetime was 1.82 ms according to the linear fitting result. Decay study reveals that the 5D0→7F2 transition of Eu3+ ions has a single exponential decay behavior.

  11. Low resistivity contacts to YBa2Cu3O(7-x) superconductors

    NASA Technical Reports Server (NTRS)

    Hsi, Chi-Shiung; Haertling, Gene H.

    1991-01-01

    Silver, gold, platinum, and palladium metals were investigated as electroding materials for the YBa2Cu3O(7-x) superconductors. Painting, embedding, and melting techniques were used to apply the electrodes. Contact resistivities were determined by: (1) type of electrode; (2) firing conditions; and (3) application method. Electrodes fired for long times exhibited lower contact resistivities than those fired for short times. Low-resistivity contacts were found for silver and gold electrodes. Silver, which made good ohmic contact to the YBa2Cu3O(7-x) superconductor with low contact resistivities was found to be the best electroding material among the materials evaluated in this investigation.

  12. Fingerprinting 2,3,7,8-tetrachlorodibenzodioxin contamination within the lower Passaic River.

    PubMed

    Quadrini, James D; Ku, Wen; Connolly, John P; Chiavelli, Deborah A; Israelsson, Peter H

    2015-07-01

    The lower Passaic River is an operable unit of the Diamond Alkali Superfund site at 80 and 120 Lister Avenue in Newark, New Jersey, USA. Between 1948 and 1969, the Diamond Shamrock Chemicals Company and its predecessors manufactured chemicals such as pesticides and phenoxy herbicides, including 2,4,5-trichlorophenol, which is a precursor to 2,4,5-trichlorophenoxyacetic acid, one of the primary components used to make the military defoliant Agent Orange. A by-product of this manufacturing process was 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD), and the site is considered the dominant source of 2,3,7,8-TCDD to the lower Passaic River and its environs. Several investigators have identified the ratio of 2,3,7,8-TCDD to total TCDD as a fingerprint for the site source. The present study presents data that establish polychlorinated dibenzodioxin/polychlorinated dibenzofuran (collectively, PCDD/F) congener and homolog fingerprints of soil and sump samples from the site. It then compares those fingerprints to the PCDD/F congener and homolog patterns in lower Passaic River sediments. The similarity of the patterns in lower Passaic River sediments to the site fingerprint indicates the site is the dominant source of the 2,3,7,8-TCDD in sediments within approximately the lower 14 miles of the lower Passaic River, excluding, for the purposes of the present discussion, Newark Bay. In addition, PCDD/F congener data indicate that the ratio of 1,3,7,8-TCDD to 2,3,7,8-TCDD is another marker of the site and corroborates the findings from the other fingerprints. PMID:25726763

  13. Fingerprinting 2,3,7,8-tetrachlorodibenzodioxin contamination within the lower Passaic River

    PubMed Central

    Quadrini, James D; Ku, Wen; Connolly, John P; Chiavelli, Deborah A; Israelsson, Peter H

    2015-01-01

    The lower Passaic River is an operable unit of the Diamond Alkali Superfund site at 80 and 120 Lister Avenue in Newark, New Jersey, USA. Between 1948 and 1969, the Diamond Shamrock Chemicals Company and its predecessors manufactured chemicals such as pesticides and phenoxy herbicides, including 2,4,5-trichlorophenol, which is a precursor to 2,4,5-trichlorophenoxyacetic acid, one of the primary components used to make the military defoliant Agent Orange. A by-product of this manufacturing process was 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD), and the site is considered the dominant source of 2,3,7,8-TCDD to the lower Passaic River and its environs. Several investigators have identified the ratio of 2,3,7,8-TCDD to total TCDD as a fingerprint for the site source. The present study presents data that establish polychlorinated dibenzodioxin/polychlorinated dibenzofuran (collectively, PCDD/F) congener and homolog fingerprints of soil and sump samples from the site. It then compares those fingerprints to the PCDD/F congener and homolog patterns in lower Passaic River sediments. The similarity of the patterns in lower Passaic River sediments to the site fingerprint indicates the site is the dominant source of the 2,3,7,8-TCDD in sediments within approximately the lower 14 miles of the lower Passaic River, excluding, for the purposes of the present discussion, Newark Bay. In addition, PCDD/F congener data indicate that the ratio of 1,3,7,8-TCDD to 2,3,7,8-TCDD is another marker of the site and corroborates the findings from the other fingerprints. Environ Toxicol Chem 2015;34:1485–1498. © 2015 The Authors. Published by SETAC. PMID:25726763

  14. Fingerprinting 2,3,7,8-tetrachlorodibenzodioxin contamination within the lower Passaic River.

    PubMed

    Quadrini, James D; Ku, Wen; Connolly, John P; Chiavelli, Deborah A; Israelsson, Peter H

    2015-07-01

    The lower Passaic River is an operable unit of the Diamond Alkali Superfund site at 80 and 120 Lister Avenue in Newark, New Jersey, USA. Between 1948 and 1969, the Diamond Shamrock Chemicals Company and its predecessors manufactured chemicals such as pesticides and phenoxy herbicides, including 2,4,5-trichlorophenol, which is a precursor to 2,4,5-trichlorophenoxyacetic acid, one of the primary components used to make the military defoliant Agent Orange. A by-product of this manufacturing process was 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD), and the site is considered the dominant source of 2,3,7,8-TCDD to the lower Passaic River and its environs. Several investigators have identified the ratio of 2,3,7,8-TCDD to total TCDD as a fingerprint for the site source. The present study presents data that establish polychlorinated dibenzodioxin/polychlorinated dibenzofuran (collectively, PCDD/F) congener and homolog fingerprints of soil and sump samples from the site. It then compares those fingerprints to the PCDD/F congener and homolog patterns in lower Passaic River sediments. The similarity of the patterns in lower Passaic River sediments to the site fingerprint indicates the site is the dominant source of the 2,3,7,8-TCDD in sediments within approximately the lower 14 miles of the lower Passaic River, excluding, for the purposes of the present discussion, Newark Bay. In addition, PCDD/F congener data indicate that the ratio of 1,3,7,8-TCDD to 2,3,7,8-TCDD is another marker of the site and corroborates the findings from the other fingerprints.

  15. The observation of the ac Josephson effect in a YBa2Cu3O7/ Au/YBa2Cu3O7 junction

    NASA Astrophysics Data System (ADS)

    Schwartz, D. B.; Mankiewich, P. M.; Howard, R. E.; Jackel, L. D.; Straughn, B. L.

    1989-03-01

    The authors have demonstrated proximity effect coupling between a high-transition-temperature superconductor and a normal metal. In a device with a 1-micron-long gap in a YBa2Cu3O7 film spanned by an Au shunt, the authors observed a dc supercurrent and the ac Josephson effect under microwave irradiation from 2 GHz to 15 GHz. Preliminary work has also begun with Ag shunts. It is concluded that these high quality S-N (superconductor-normal) interfaces should be applicable both to probing the superconducting state in oxide superconductors and to building high-Tc electronic devices.

  16. Local Environment Study of Eu3+ Doped KGd2F7 by Site-Selective Spectroscopy.

    PubMed

    Qin, Yanguang; Wei, Xiantao; Wen, Jun; Chen, Yonghu; Yin, Min

    2016-04-01

    The site-selective spectra and decay curves at 20 K of Eu3+ ions doped KGd2F7 were measured to study the local environment of the Eu3+ sites. The experimental results show that Eu3+ ions occupy three types of sites in the KGd2F7 host. And Eu3+ ions in different types of sites exhibit quite distinct emission spectra and have remarkably different 5D0 level decay lifetimes. Based on the intensity ratio of 5D0--> 7F2,1 transitions of Eu3+ and the 5D0 decay lifetimes in different types of sites, the correlation between the luminescent properties and the site symmetry is discussed. PMID:27451728

  17. Luminescence Properties of Sr2MgSi2O7:Eu2+, Ce3+ Phosphor by Solid State Reaction Method

    NASA Astrophysics Data System (ADS)

    Sahu, Ishwar Prasad; Bisen, D. P.; Brahme, Nameeta; Wanjari, Lata; Tamrakar, Raunak

    The Sr2MgSi2O7:Eu2+, Ce3+ phosphor was prepared by solid state reaction method, boric acid (H3BO3) was added as flux. The phase structure of Sr2MgSi2O7:Eu2+, Ce3+ phosphor was akermanite type structure which belongs to the tetragonal crystallography with space group

  18. Superconducting single crystalline YBa2Cu3O7- δ on SrTiO3 buffered Si (100)

    NASA Astrophysics Data System (ADS)

    Jahangir Moghadam, Mohammadreza; Ahmadi Majlan, Kamyar; Zhang, Hao; Shen, Xuan; Chrysler, Matthew; Conlin, Patrick; Hensley, Ricky; Su, Dong; Wei, John; Ngai, Joseph

    2015-03-01

    The growth of crystalline oxides on semiconductors enables new functionalities to be integrated with semiconducting technologies. Here, thin films of optimally-doped (001)-oriented YBa2Cu3O7- δ are epitaxially integrated on silicon (001) through growth on a SrTiO3 buffer. The former is grown using pulsed-laser deposition and the latter is grown on Si using oxide molecular beam epitaxy. The single crystal nature of the SrTiO3 buffer enables very high transition temperatures to be achieved. For a 30 nm thick SrTiO3 buffer, YBa2Cu3O7- δ films exhibiting a transition temperature of ~ 95 K, and a narrow transition width (<5 K) are achieved. The integration of single crystalline YBa2Cu3O7- δ on Si (001) paves the way for the potential exploration of cuprate materials in a variety of applications.

  19. X?-DVM modelling of oxygen transport in YBa2Cu3O7-? and SrFeO3

    NASA Astrophysics Data System (ADS)

    Yuryeva, Elmira I.

    The reasons for oxygen transport in YBa2Cu3O7-? and SrFeO3 were investigated, using the X?-discrete variation method. Reduced binding energy and other parameters of the electronic energy structure were calculated for a number of crystal fragments within the T and O phases of YBa2Cu3O7-? and the cubic phase of SrFeO3. The following results were obtained: (i) test calculations of reduced binding energy confirmed that high temperature should be a condition of existence of the T phase, as compared with the O phase of YBa2Cu3O7-?; (ii) an increase in temperature up to ?400°C points to the beginning of the Jahn-Teller dynamic effect in SrFeO3; and (iii) transport of neutral and charged oxygen atoms results in distributions of stable and unstable oxygen vacancies, respectively.

  20. Nqrs Data for C8H7ClN2O3 (Subst. No. 1078)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C8H7ClN2O3 (Subst. No. 1078)

  1. Enhanced ionic conductivity with Li7O2Br3 phase in Li3OBr anti-perovskite solid electrolyte

    NASA Astrophysics Data System (ADS)

    Zhu, Jinlong; Li, Shuai; Zhang, Yi; Howard, John W.; Lü, Xujie; Li, Yutao; Wang, Yonggang; Kumar, Ravhi S.; Wang, Liping; Zhao, Yusheng

    2016-09-01

    Cubic anti-perovskites with general formula Li3OX (X = Cl, Br, I) were recently reported as superionic conductors with the potential for use as solid electrolytes in all-solid-state lithium ion batteries. These electrolytes are nonflammable, low-cost, and suitable for thermoplastic processing. However, the primary obstacle of its practical implementation is the relatively low ionic conductivity at room temperature. In this work, we synthesized a composite material consisting of two anti-perovskite phases, namely, cubic Li3OBr and layered Li7O2Br3, by solid state reaction routes. The results indicate that with the phase fraction of Li7O2Br3 increasing to 44 wt. %, the ionic conductivity increased by more than one order of magnitude compared with pure phase Li3OBr. Formation energy calculations revealed the meta-stable nature of Li7O2Br3, which supports the great difficulty in producing phase-pure Li7O2Br3 at ambient pressure. Methods of obtaining phase-pure Li7O2Br3 will continue to be explored, including both high pressure and metathesis techniques.

  2. Specific heat evidence for strong coupling in YBa sub 2 Cu sub 3 O sub 7

    SciTech Connect

    Gordon, J.E.; Fisher, R.A.; Kamin, S.; Phillips, N.E.

    1990-08-01

    Specific heat data for YBa{sub 2}Cu{sub 3}O{sub 7} are consistent with {gamma} = 15 {plus minus} 3 mJ/mole{center dot}K{sup 2} and 2{Delta}{sub 0}/k{Tc} = 6.8 {plus minus} 0.6. These results indicate that strong-coupling effects are present but that the coupling is unlikely to be predominantly a conventional electron-phonon interaction. 8 refs., 1 fig.

  3. Laser ablated YBa2Cu3O(7-x) high temperature superconductor coplanar waveguide resonator

    NASA Technical Reports Server (NTRS)

    Valco, G. J.; Blemker, A. R.; Bhasin, K. B.

    1992-01-01

    Several 8.8-GHz coplanar waveguide resonators are fabricated and tested that are made from laser ablated YBa2Cu3O(7-x) thin films on LaAlO3 substrates. A quality factor of 1250 at 77 K was measured. A correlation between the microwave performance of the resonators and the critical temperature and morphology of the films was observed.

  4. 40 CFR 721.8500 - 2-Propenoic acid, 2-methyl-, 7-oxabicyclo [4.1.0]hept-3-ylmethyl ester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-oxabicyclo hept-3-ylmethyl ester. 721.8500 Section 721.8500 Protection of Environment ENVIRONMENTAL... hept-3-ylmethyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance 2-propenoic acid, 2-methyl-, 7-oxabicyclo hept-3-ylmethyl ester (PMN P-89-30) is...

  5. 40 CFR 721.8500 - 2-Propenoic acid, 2-methyl-, 7-oxabicyclo [4.1.0]hept-3-ylmethyl ester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-oxabicyclo hept-3-ylmethyl ester. 721.8500 Section 721.8500 Protection of Environment ENVIRONMENTAL... hept-3-ylmethyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance 2-propenoic acid, 2-methyl-, 7-oxabicyclo hept-3-ylmethyl ester (PMN P-89-30) is...

  6. Temperature behaviour of optical parameters in (Ag3AsS3)0.3(As2S3)0.7 thin films

    NASA Astrophysics Data System (ADS)

    Kutsyk, Mykhailo M.; Ráti, Yosyp Y.; Izai, Vitalii Y.; Makauz, Ivan I.; Studenyak, Ihor P.; Kökényesi, Sandor; Komada, Paweł; Zhailaubayev, Yerkin; Smailov, Nurzhigit

    2015-12-01

    (Ag3AsS3)0.3(As2S3)0.7 thin films were deposited onto a quartz substrate by rapid thermal evaporation. The optical transmission spectra of thin films were measured in the temperature range 77-300 K. It is shown that the absorption edge spectra are described by the Urbach rule. The temperature behaviour of absorption spectra was studied, the temperature dependences of energy position of absorption edge and Urbach energy were investigated. The influence of transition from three-dimensional glass to the two-dimensional thin film as well as influence of Ag3AsS3 introduction into As2S3 on the optical parameters of (Ag3AsS3)0.3(As2S3)0.7 were analysed. The spectral and temperature behaviour or refractive index for (Ag3AsS3)0.3(As2S3)0.7 thin film were studied.

  7. Gridded atmospheric emission inventory of 2,3,7,8-TCDD in China

    NASA Astrophysics Data System (ADS)

    Huang, Tao; Tian, Chongguo; Zhang, Kai; Gao, Hong; Li, Yi-Fan; Ma, Jianmin

    2015-05-01

    Establishment of the dioxins emission inventory has been considered as a crucial step toward risk assessment and elimination of dioxins contaminations. Based on a total dioxin emission inventory in China from different emission categories in 2004, this study created a gridded emission inventory of 2,3,7,8-TCDD, the most toxic congener in dioxins, in China in 2009 with a 1/4° longitude by 1/4° latitude resolution. It was estimated that annually total 371 ± 53 g (average ± standard deviation) of 2,3,7,8-TCDD was released into the atmosphere in 2009 over China, increasing approximately by 37% compared with its emission in 2004. Differing from most developed countries where municipal waste incinerations were regarded as a major atmospheric emission source, in China ferrous and non-ferrous metal production made the largest contribution to 2,3,7,8-TCDD air emission (138 ± 16 g), followed by waste incineration (109 ± 12 g), power and heating generation (62 ± 9 g), and production of mineral products (47 ± 8 g). The rest of sources contributed approximately 3% to the total 2,3,7,8-TCDD emission in 2009. Iron and steel industries are mainly located in Beijing-Tianjin-Hebei (BTH) and Yangtze River Delta (YRD) regions, whereas waste incinerators are mainly located in Pearl River Delta (PRD) region. Higher 2,3,7,8-TCDD emissions were found in these three regions. While the BTH, YRD, and PRD accounted for only about 4% of total land area of China, they contributed approximately 14%, 15%, and 5% to the total 2,3,7,8-TCDD emission in 2009 in China, respectively.

  8. Assessment of RELAP5/MOD3 Version 7 based on the BETHSY Test 6. 2 TC

    SciTech Connect

    Choi, C.J. ); Roth, P.A.; Schultz, R.R. )

    1992-01-01

    This document provides a discussion of the BETHSY test 6.2 TC which was conducted to investigate thermal hydraulic phenomena during a 5% cold leg SBLOCA and to provide high quality data for advanced thermal-hydraulic code assessment. BETHSY test 6.2 TC was analyzed using RELAP5/MOD3 version 7o.

  9. Hybrid improper ferroelectricity in Ruddlesden-Popper Ca3(Ti,Mn)2O7 ceramics

    NASA Astrophysics Data System (ADS)

    Liu, X. Q.; Wu, J. W.; Shi, X. X.; Zhao, H. J.; Zhou, H. Y.; Qiu, R. H.; Zhang, W. Q.; Chen, X. M.

    2015-05-01

    The hybrid improper ferroelectricity (HIF) has been proposed as a promising way to create multiferroic materials with strong magnetoelectric coupling by the first-principle calculation, and the experimental evidences of HIF in Ruddlesden-Poper Ca3(Ti1-xMnx)2O7 (x = 0, 0.05, 0.1, and 0.15) ceramics have been shown in the present work. The room temperature ferroelectric hysteresis loops are observed in these ceramics, and a polar orthorhombic structure with two oxygen tilting modes has been confirmed by the X-ray powder diffraction. A first-order phase transition around 1100 K in Ca3Ti2O7 was evidenced, and the temperatures of phase transitions decrease linearly with increasing of the contents of Mn4+ ions. Based on the result of first-principle calculations, the polarization should be reversed by switching through the mediated Amam phase in Ca3Ti2O7 ceramics.

  10. Magic wavelengths for the 7s1/2-6d3/2,5/2 transitions in Ra+

    NASA Astrophysics Data System (ADS)

    Wu, Xiao-Mei; Li, Cheng-Bin; Tang, Yong-Bo; Shi, Ting-Yun

    2016-09-01

    The dynamic polarizabilities of the 7s and 6d states of Ra+ are calculated using a relativistic core polarization potential method. The magic wavelengths of the 7s1/2-6d3/2,5/2 transitions are identified. Comparing to the common radio-frequency (RF) ion traps, using the laser field at the magic wavelength to trap the ion could suppress the frequency uncertainty caused by the micromotion of the ion, and would not affect the transition frequency measurements. The heating rates of the ion and the powers of the laser for the ion trapping are estimated, which would benefit the possible precision measurements based on all-optical trapped Ra+. Project supported by the National Basic Research Program of China (Grant No. 2012CB821305) and the National Natural Science Foundation of China (Grant Nos. 91336211 and 11504094).

  11. Magic wavelengths for the 7s1/2‑6d3/2,5/2 transitions in Ra+

    NASA Astrophysics Data System (ADS)

    Wu, Xiao-Mei; Li, Cheng-Bin; Tang, Yong-Bo; Shi, Ting-Yun

    2016-09-01

    The dynamic polarizabilities of the 7s and 6d states of Ra+ are calculated using a relativistic core polarization potential method. The magic wavelengths of the 7s1/2‑6d3/2,5/2 transitions are identified. Comparing to the common radio-frequency (RF) ion traps, using the laser field at the magic wavelength to trap the ion could suppress the frequency uncertainty caused by the micromotion of the ion, and would not affect the transition frequency measurements. The heating rates of the ion and the powers of the laser for the ion trapping are estimated, which would benefit the possible precision measurements based on all-optical trapped Ra+. Project supported by the National Basic Research Program of China (Grant No. 2012CB821305) and the National Natural Science Foundation of China (Grant Nos. 91336211 and 11504094).

  12. Process for manufacturing bis(2-methoxyethyl)-2,3,6,7-tetracyano-1,4,5,8,9,10-hexazaanthracene

    DOEpatents

    Rasmussen, Paul George; Lawton, Richard Graham

    2014-06-03

    A process to manufacture substituted tetracyano-hexaazatricyclics with the substitutions occurring at the 9 and 10 hydrogens. The process begins with 2,3-dichloro-5,6-dicyanopyrazine, which is reacted to form the desired tetracyano-hexaazatricyclic. Different process embodiments enable different reaction paths to the desired tetracyano-hexaazatricyclic. Different tetracyano-hexaazatricyclic embodiments include bis(2-methoxyethyl)-2,3,6,7-tetracyano-1,4,5,8,9,10-hexazaanthracene and bis(2-methoxyethoxyethyl)-2,3,6,7-tetracyano-1,4,5,8,9,10-hexazaanthracen- e.

  13. Study of deposition of YBa2Cu3O7-x on cubic zirconia

    NASA Technical Reports Server (NTRS)

    Warner, Joseph D.; Meola, Joseph E.; Jenkins, Kimberly A.

    1989-01-01

    Films of YBa2Cu3O7-x were grown on (100) cubic zirconia with 8 percent yttria by laser ablation from sintered targets of YBa2Cu3O7-x. The temperature of the zirconia substrate during growth was varied between 700 and 780 C. The atmosphere during growth was 170 mtorr of O2. The films were subsequently slowly cooled in-situ in 1 atm of O2. The best films were c-axis aligned and had a transition temperature of 87.7 K. The superconducting transition temperature and the X-ray diffraction analysis is reported as a function of the substrate temperature and of the angle between the laser beam and the target's normal.

  14. Comparative study of the Mn4+2E → 4A2 luminescence in isostructural RE2Sn2O7:Mn4+ pyrochlores (RE3+ = Y3+, Lu3+ or Gd3+)

    NASA Astrophysics Data System (ADS)

    Senden, Tim; Broers, Fréderique T. H.; Meijerink, Andries

    2016-10-01

    Red emitting Mn4+-doped crystalline materials have potential for application in light emitting devices and therefore it is important to understand how the optical properties of Mn4+ are influenced by the host lattice the Mn4+ ions are situated in. In this work we investigate the effect of the host cations in the second coordination sphere on the Mn4+ emission by studying the luminescence of Mn4+ ions doped into three isostructural rare earth (RE) stannate RE2Sn2O7 pyrochlores (RE3+ = Y3+, Lu3+ or Gd3+). It is found that the energies of the Mn4+4T1 and 4T2 states significantly increase with decreasing Mn4+-O2- distance, whereas the energy of the 2E level shows a small shift to higher energies from RE3+ = Gd3+ to Lu3+ to Y3+. The observed trend for the 2E level energy is not related to the size of the RE3+ ion and is not in line with theoretical calculations reported previously. Low temperature emission spectra of the RE2Sn2O7:Mn4+ phosphors reveal that only asymmetrical vibronic modes couple to the 2E → 4A2 transition and furthermore show there is significant and unexpected local disorder for Mn4+ in Gd2Sn2O7 that is not observed for Mn4+ in the other hosts. Photoluminescence decay measurements demonstrate that the luminescence of RE2Sn2O7:Mn4+ is strongly quenched below room temperature which is assigned to non-radiative relaxation via a low-lying O2- → Mn4+ charge-transfer state.

  15. Synthesis of Al2O3 nanoparticles highly distributed in YBa2Cu3O7 superconductor by citrate-nitrate auto-combustion reaction

    NASA Astrophysics Data System (ADS)

    Suan, Mohd Shahadan Mohd; Johan, Mohd Rafie

    2013-09-01

    The effects of Al2O3 nanoparticles on the structure and superconducting properties of YBa2Cu3O7-δ matrix prepared by auto-combustion reaction were investigated. The auto-combustion reaction has successfully transformed the Al nitrate added YBCO precursor gels to very fine ashes which yielded to Al2O3 and YBCO phases after the calcination process at 900 °C. The resultant reactions produced nanocrystalline YBa2Cu3O7-δ powders having well distributed Al2O3 nanoparticles (∼10 nm). The TG/DTA analysis reveals that the Al nitrate added precursor gels decomposed by two-steps reaction at temperature of 180 and 220 °C due to the decomposition of Al nitrate followed by Y, Ba and Cu nitrates. The XRD pattern showed the orthorhombic structure of Al2O3 added YBa2Cu3O7-δ powders having the particle size ranged in between 20 and 25 nm. SEM analysis showed that Al2O3 nanoparticles were distributed along the grain boundaries of YBa2Cu3O7-δ matrix for the higher mol of Al nitrate. The higher concentration of Al2O3 reacts with the YBa2Cu3O7 matrix to form Al3+ rich spots and diffuse within the YBa2Cu3O7-δ superconducting matrix which was confirmed by EDX analysis. The samples produced in this work were electrically superconducting at temperature above 85 K as measured by using standard four-probe technique. Formation of alumina precipitates and incorporation of Al3+ into YBa2Cu3O7-δ structure was found to significantly reduce the Tc of pure YBa2Cu3O7-δ.

  16. Enhancement of photoluminescence in Eu3+ co-activated Ca2MgSi2O7:Dy3+ phosphors for solid state lighting application

    NASA Astrophysics Data System (ADS)

    Mondal, Kanchan; Manam, J.

    2016-12-01

    A series of Ca2MgSi2O7:Dy3+, Ca2MgSi2O7:Eu3+and Ca2MgSi2O7:Dy3+, Eu3+phosphors were synthesized by conventional solid state reaction method. The X-ray diffraction (XRD) patterns were recorded to confirm the phase purity of Ca2MgSi2O7 phosphors. The XRD results showed that the prepared phosphors have single-phase tetragonal structure and incorporation of dopants has no effect on the crystal structure of phosphors. The surface morphological studies were performed using field emission scanning electronic spectroscopy (FESEM). Photoluminescence (PL) properties were systematically investigated in detail. With increasing, Dy3+ concentration the PL intensity first increases, reaches the maximum and then it was decreased. A Similar trend was shown in Ca2MgSi2O7:Eu3+ phosphors. The PL emission intensity was increased at the transitions 5D0 → 7F1 and 5D0 → 7F2 with increasing Eu3+ concentration while decreased the intensity at the transitions 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2. The calculated band gap values of the sample were found to be 4.29, 4.38, 4.11 and 4.23 eV.

  17. Electron backscatter diffraction study of polycrystalline YBa 2Cu 3O 7- δ ceramics

    NASA Astrophysics Data System (ADS)

    Koblischka-Veneva, Anjela; Koblischka, Michael R.; Simon, Petra; Mücklich, Frank; Murakami, Masato

    2002-11-01

    The electron backscatter diffraction (EBSD) technique was applied to polycrystalline YBa 2Cu 3O 7- δ ceramics. To obtain good quality EBSD Kikuchi patterns on the ceramic superconductors, a new sample polishing route was established. Samples with and without KClO 3-doping were investigated; and the crystallographic orientations of the grains were analyzed using pole figures and EBSD orientation mapping. On the polycrystalline KClO 3-doped YBa 2Cu 3O 7- δ samples we found two major orientations (0 0 1) and (1 0 0) normal to the sample surface, while the undoped sample did not exhibit any orientation maxima. We ascribe this observation to the effect of a liquid phase due to the KClO 3-additive during the preparation process.

  18. A conserved threonine in the S1-S2 loop of KV7.2 and K V7.3 channels regulates voltage-dependent activation.

    PubMed

    Füll, Yvonne; Seebohm, Guiscard; Lerche, Holger; Maljevic, Snezana

    2013-06-01

    The voltage-gated potassium channels KV7.2 and KV7.3 (KCNQ2/3 genes) play an important role in regulating neuronal excitability. More than 50 KCNQ2/3 mutations have been identified to cause an inherited form of epilepsy in newborns. For two of those (E119G and S122L) found in the S1-S2 region of KV7.2, we previously showed a decreased channel availability mainly at action potential subthreshold voltages caused by a slight depolarizing shift of the activation curve. Interestingly, recent studies revealed that a threonine residue within the S1-S2 loop, highly conserved among different classes of KV channels, is crucial for both their function and surface expression. To investigate the functional role of the homologous threonine residues in KV7.2 (T114) and KV7.3 (T144) channels, we replaced them with alanine and examined the electrophysiological properties using heterologous expression in CHO cells and whole cell patch clamping. Channels comprising mutant subunits yielded decreased potassium currents with slowed activation and accelerated deactivation kinetics. However, the most striking effect was a depolarizing shift in the voltage dependence of activation reaching +30 mV upon co-expression of both mutant subunits. Potential interactions of T114 within the channel were analyzed by creating a 3D homology model of KV7.2 in an open state suggesting that this residue plays a central role in the formation of a stable interface between the S1-S2 and the S5 segment helices. This could be the explanation why substitution of the conserved threonine in KV7.2 and KV7.3 channels destabilizes the open and favors the closed state of these channels.

  19. Effect of defect state on photon synergistic process in KLu2F7:Yb3+, Er3+ nanoparticles

    NASA Astrophysics Data System (ADS)

    Bian, Wenjuan; Lu, Wei; Qi, Yushuang; Yu, Xue; Zhou, Dacheng; Yang, Yong; Qiu, Jianbei; Xu, Xuhui

    2016-10-01

    The synergistic effect appeared due to the cooperative dual-wavelength excitation by near-infrared (NIR) and ultraviolet (UV) light in rare-earth doped nano-particles (NPs) is very important to improve solar cell efficiency. Herein, we studied the synergistic effect combined with the energy levels of Er3+ ions and the defect states in KLu2F7 NPs. The introduction of Ce3+ ions in KLu2F7:16%Yb3+, 2%Er3+ NPs results in significant improvement of synergistic effect by producing more vacancy defects (VK‧) which serves as shallow traps. We verify unambiguously that the control of the defects distribution exerts a facile approach to promote the synergistic effect with the assistance of Ce3+ ions doping.

  20. HEALTH RISK ASSESSMENT APPROACH FOR 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (1985)

    EPA Science Inventory

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is one of the most toxic and environmentally stable pollutants. In addition to various toxic effects, TCDD has been found to cause teratogenic, fetocidal, reproductive and carcinogenic effects in animals. In humans it adversely affects v...

  1. Forming YBa2Cu3O7-x Superconductors On Copper Substrates

    NASA Technical Reports Server (NTRS)

    Mackenzie, J. Devin; Young, Stanley G.

    1991-01-01

    Experimental process forms layer of high-critical-temperature ceramic superconductor YBa2Cu3O7-x on surface of copper substrate. Offers possible solution to problem of finishing ceramic superconductors to required final sizes and shapes (difficult problem because these materials brittle and cannot be machined or bent). Further research necessary to evaluate superconducting qualities of surface layers and optimize process.

  2. ANALYSIS OF 2,3,7,8-TCDD TUMOR PROMOTION ACTIVITY AND ITS RELATIONSHIP TO CANCER

    EPA Science Inventory

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has a high estimated cancer potency in animals which has been reasoned to imply that TCDD might be carcinogenic to man. The animal cancer data show that TCDD can act in a solitary manner causing tumors without the participation of other ...

  3. Structure and formation of H2Ti3O7 nanotubes in an alkali environment

    NASA Astrophysics Data System (ADS)

    Zhang, S.; Chen, Q.; Peng, L.-M.

    2005-01-01

    The structure and growth of H2Ti3O7 -type nanotubes have been studied by first-principle calculations. It is shown that the asymmetry in the distribution of hydrogen on the two sides of the surface layer of a H2Ti3O7 crystal plate provides a sufficient driving force for the formation of the H2Ti3O7 nanotube. Hydrogen deficiency on one side of the surface layer of a H2Ti3O7 plate results in a surface tension that increases with increasing hydrogen deficiency and may eventually overcome the coupling from the layers beneath driving the surface layer to peel off from the crystal plate and roll into a tubular structure. While the radius of the resultant nanotube is determined mainly by the layer coupling energy, the thickness of the tube wall is determined by the residual charges on the peeled surface layer. Both the radius and the wall thickness may in principle be controlled via modifying the layer coupling strength and the net charges on the surface.

  4. PrBa{sub 2}Cu{sub 3}O{sub 7}: A new superconductor

    SciTech Connect

    Blackstead, H.A.; Dow, J.D.

    1995-10-01

    PrBa{sub 2}Cu{sub 3}O{sub 7} superconducts, provided Pr is kept off Ba-sites - experimentally confirming the prediction of the oxygen model and indicating that superconductivity originates in the chains, not in the planes.

  5. SORPTION OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN FROM WATER BY SURFACE SOILS

    EPA Science Inventory

    The sorption of l4C-labeled 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) from water by two uncontaminated surface soils from the Times Beach, MO, area was evalu- ated by using batch shake testing. Sorption isotherm plots for the soil with the lower fraction organic carbon (f,) wer...

  6. Antihypertensive activity of 6-arylpyrido[2,3-d]pyrimidin-7-amine derivatives.

    PubMed

    Bennett, L R; Blankley, C J; Fleming, R W; Smith, R D; Tessman, D K

    1981-04-01

    A series of 51 6-arylpyrido[2,3-d]pyrimidin-7-amine derivatives was prepared and evaluated for antihypertensive activity in the conscious spontaneously hypertensive rat. A number of these compounds, notably 6-(2,6-dichlorophenyl)-2-methylpyrido[2,3-d]pyrimidin-7-amine (36), lowered blood pressure in these rats in a gradual and sustained manner to normotensive levels at oral doses of 10-50 mg/kg. Normalized blood pressure levels could then be maintained by single daily oral doses. The effect of structural variation in the 6-aryl group and in the 2 and 4 positions of the pyridopyrimidine ring on activity is reported and discussed.

  7. Fabrication of YBa2Cu3O7 thin film on cube-textured Cu tape

    NASA Astrophysics Data System (ADS)

    Tokudome, Makoto; Doi, Toshiya; Tomiyasu, Ryota; Sato, Shinya; Hakuraku, Yoshinori; Kubota, Shuichi; Shima, Kunihiro; Kashima, Naoji; Nagaya, Shigeo

    2008-11-01

    We achieved a biaxially oriented YBa2Cu3O7 film on a {100} ⟨001⟩ textured Cu tape with Jc of 1.9×106 A cm-2 at 77 K. A Ni overlayer was deposited by electroplating technique on the {100} ⟨001⟩ textured Cu tape to improve oxidation resistance of Cu substrate, and then YBa2Cu3O7 was deposited on the CeO2/YSZ/CeO2 buffered Ni-electroplated Cu tape. We confirmed that the Ni-electroplated Cu tape lost its ferromagnetism after 700 °C at 1 h heat treatment. Our rolling assisted biaxially textured substrate (RABiTS) type coated conductor can be used for ac applications and is thought to be more cost feasible than the standard RABiTS architecture using Ni-alloy tapes.

  8. The CYP2A3 gene product catalyzes coumarin 7-hydroxylation in human liver microsomes

    SciTech Connect

    Yamano, Shigeru; Tatsuno, Jun; Gonzalez, F.J. )

    1990-02-06

    Three cDNAs, designated IIA3, IIA3v, and IIA4, coding for P450s in the CYP2A gene subfamily were isolated from a {lambda}gt11 library prepared from human hepatic mRNA. Only three nucleotide differences and a single amino acid difference, Leu{sup 160}{yields}His, were found between IIA3 and IIA3v, indicating that they are probably allelic variants. IIA4 displayed 94% amino acid similarity with IIA3 and IIA3v. The three cDNAs were inserted into vaccinia virus, and recombinant viruses were used to infect human hepatoma Hep G2 cells. Only IIA3 was able to produce an enzyme that had a reduced CO-bound spectrum with a {lambda}{sub max} at 450 nm. This expressed enzyme was able to carry out coumarin 7-hydroxylation and ethoxycoumarin O-deethylation. cDNA-expressed IIA3v and IIA4 failed to incorporate heme and were enzymatically inactive. Analysis of IIA proteins in human liver microsomes, using antibody against rat IIA2, revealed two proteins of 49 and 50 kDa, the former of which appeared to correlate with human microsomal coumarin 7-hydroxylase activity. A more striking correlation was found between IIa mRNA and enzyme activity. The rat antibody was able to completely abolish coumarin 7-hydroxylase activity in 12 liver samples. These data establish that the CYP2A3 gene product is primarily responsible for coumarin 7-hydroxylase activity in human liver. The level of expression of this activity varied up to 40-fold between livers. Levels of IIA mRNA also varied significantly between liver specimens, and three specimens had no detectable mRNA.

  9. Superconductivity and magnetic ordering in YBa2(Cu1- x Fe x )3O7

    NASA Astrophysics Data System (ADS)

    Kossler, W. J.; Yu, X. H.; Greer, A.; Schone, H. E.; Stronach, C. E.; Davis, M.; Cary, R. S.; Lankford, W. F.; Moodenbaugh, A.; Oostens, J.

    1991-02-01

    Transverse-and zero-field μSR measurements have been made for YBa2(Cu1- x Fe x )3O7 with x=0.04, 0.08 and 0.12. The temperature range studied was from approximately 7.5 K to 100 K. The onset of magnetic ordering commences at about 7.5 K for x=0.04, 10 K for x=0.08 and 20 K for x=0.12. The Gaussian depolarization parameter, σ of G x ( t) = exp(-σ2 t 2/2), is depressed by a factor of about 0.6 for x=0.04, but for the x=0.08 sample σ is depressed by a factor of 10 and increasing suppression is seen as the temperature is lowered below 45 K. This decrease in σ is interpreted in terms of decreasing electronic mean free paths.

  10. Coherent quasiparticles with a small fermi surface in lightly doped Sr(3)Ir(2)O(7).

    PubMed

    de la Torre, A; Hunter, E C; Subedi, A; McKeown Walker, S; Tamai, A; Kim, T K; Hoesch, M; Perry, R S; Georges, A; Baumberger, F

    2014-12-19

    We characterize the electron doping evolution of (Sr_{1-x}La_{x})_{3}Ir_{2}O_{7} by means of angle-resolved photoemission. Concomitant with the metal insulator transition around x≈0.05 we find the emergence of coherent quasiparticle states forming a closed small Fermi surface of volume 3x/2, where x is the independently measured La concentration. The quasiparticle weight Z remains large along the entire Fermi surface, consistent with the moderate renormalization of the low-energy dispersion, and no pseudogap is observed. This indicates a conventional, weakly correlated Fermi liquid state with a momentum independent residue Z≈0.5 in lightly doped Sr_{3}Ir_{2}O_{7}. PMID:25554897

  11. Coherent quasiparticles with a small fermi surface in lightly doped Sr(3)Ir(2)O(7).

    PubMed

    de la Torre, A; Hunter, E C; Subedi, A; McKeown Walker, S; Tamai, A; Kim, T K; Hoesch, M; Perry, R S; Georges, A; Baumberger, F

    2014-12-19

    We characterize the electron doping evolution of (Sr_{1-x}La_{x})_{3}Ir_{2}O_{7} by means of angle-resolved photoemission. Concomitant with the metal insulator transition around x≈0.05 we find the emergence of coherent quasiparticle states forming a closed small Fermi surface of volume 3x/2, where x is the independently measured La concentration. The quasiparticle weight Z remains large along the entire Fermi surface, consistent with the moderate renormalization of the low-energy dispersion, and no pseudogap is observed. This indicates a conventional, weakly correlated Fermi liquid state with a momentum independent residue Z≈0.5 in lightly doped Sr_{3}Ir_{2}O_{7}.

  12. Hexachlorodibenzo-p-dioxin (HxCDD), mixture of 1,2,3,6,7,8-HxCDD and 1,2,3,7,8,9-HxCDD

    Integrated Risk Information System (IRIS)

    Hexachlorodibenzo - p - dioxin ( HxCDD ) , mixture of 1,2,3,6,7,8 - HxCDD and 1,2,3,7,8,9 - HxCDD ; CASRN 57653 - 85 - 7 and 19408 - 74 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in

  13. Direct Observation of Long-Term Durability of Superconductivity in YBa2Cu3O7-Ag2O Composites

    NASA Astrophysics Data System (ADS)

    Lin, Juhn-Jong; Lin, Yong-Han; Huang, Shiu-Ming; Lee, Tsang-Chou; Chen, Teng-Ming

    2003-10-01

    We report direct observation of long-term durability of superconductivity of several YBa2Cu3O7-Ag2O composites that were first prepared and studied almost fourteen years ago [J. J. Lin et al.: Jpn. J. Appl. Phys. 29 (1990) 497]. Remeasurements performed recently on both resistances and magnetizations indicate a sharp critical transition temperature at 91 K. We also find that such long-term environmental stability of high-temperature superconductivity can only be achieved in YBa2Cu3O7 with Ag2O addition, but not with pure Ag addition.

  14. Optical cascade pumping of the 7P{sub 3/2} level in cesium atoms

    SciTech Connect

    Kargapol'tsev, Sergei V; Velichansky, Vladimir L; Yarovitsky, Alexander V; Taichenachev, Aleksei V; Yudin, Valerii I

    2005-07-31

    Doppler-free absorption spectra of resonance laser fields are studied upon two-stage excitation of cesium atoms according to the schemes 6S{sub 1/2{yields}}6P{sub 3/2{yields}}6D{sub 5/2} and 6S{sub 1/2{yields}}6P{sub 3/2{yields}}8S{sub 1/2}. The obtained experimental results are in qualitative agreement with the theory. In the case of weak absorption saturation, the width of resonances is mainly determined by two-photon transitions. The efficiencies of the two variants of two-stage excitation of the 7P{sub 3/2} level are compared. The possibility of fabrication of a gas laser operating on the 455-nm 7P{sub 3/2{yields}}6S{sub 1/2} transition with the optical depopulation of the lower operating level by an additional laser is discussed. (active media)

  15. Photocatalytic activity of R3MO7 and R2Ti2O7 (R=Y, Gd, La; M=Nb, Ta) for water splitting into H2 and O2.

    PubMed

    Abe, Ryu; Higashi, Masanobu; Sayama, Kazuhiro; Abe, Yoshimoto; Sugihara, Hideki

    2006-02-01

    The photocatalytic activities of R3MO7 and R2Ti2O7 (R=Y, Gd, La; M=Nb, Ta) strongly depended on the crystal structure. Overall, photocatalytic water splitting into H2 and O2 proceeded over La3TaO7 and La3NbO7, which have an orthorhombic weberite structure, Y2Ti2O7 and Gd2Ti2O7, which have a cubic pyrochlore structure, and La2Ti2O7, which has a monoclinic perovskite structure. All of these materials are composed of a network of corner-shared octahedral units of metal cations (TaO6, NbO6, or TiO6); materials without such a network were inactive. The octahedral network certainly increased the mobility of electrons and holes, thereby enhancing photocatalytic activity.

  16. Structural and magnetic field effects on spin fluctuations in Sr3Ru2O7

    NASA Astrophysics Data System (ADS)

    Mukherjee, Shantanu; Lee, Wei-Cheng

    2016-08-01

    We investigate the evolution of magnetic excitations in Sr3Ru2O7 in the paramagnetic metallic phase using a three-band tight-binding model. The effect of Mn or Ti dopant ions on the Sr3Ru2O7 band structure has been included by taking into account the dopant-induced suppression of the oxygen octahedral rotation in the tight-binding band structure. We find that the low-energy spin fluctuations are dominated by three wave vectors around q ⃗=( (0 ,0 ) ,(π /2 ,π /2 ) ) and (π ,0 ) , which compete with each other. As the octahedral rotation is suppressed with increasing doping, the three wave vectors evolve differently. In particular, the undoped compound has dominant wave vectors at q ⃗=( (0 ,0 ) ,(π /2 ,π /2 ) ) , but doping Sr3Ru2O7 leads to a significant enhancement in the spin susceptibility at the q ⃗=(π ,0 ) wave vector, bringing the system closer to a magnetic instability. All the features calculated from our model are in agreement with neutron scattering experiments. We have also studied the effect of a c -axis Zeeman field on the low-energy spin fluctuations. We find that an increasing magnetic field suppresses the antiferromagnetic (AFM) fluctuations and leads to stronger competition between the AFM and ferromagnetic spin fluctuations. The magnetic field dependence observed in our calculations therefore supports the scenario that the observed nematic phase in the metamagnetic region in Sr3Ru2O7 is intimately related to the presence of a competing ferromagnetic instability.

  17. Solid state decomposition studies on fluoroperoxo species of transition metals. IV. Photodecomposition of K 3Zr 2(O 2) 2F 7 · 2H 2O

    NASA Astrophysics Data System (ADS)

    Jere, G. V.; Kaushik, S. M.

    1980-07-01

    The kinetics of photodecomposition of solid K 3Zr 2(O 2) 2F 7 · 2H 2O have been studied under vacuum as a function of intensity and temperature by measuring the evolved oxygen with the help of a McLeod Gauge. Pressure-time curves are parabolic in nature and the data fit the empirical equation p = kt {1}/{2}. The rate of photodecomposition is a linear function of intensity. The activation energy determined from an Arrhenius plot, in the temperature range 15-55°C, of the title compound is 2.15 kcal mole -1 (9.00 kJ mole -1).

  18. Dopant concentration dependent optical and X-Ray induced photoluminescence in Eu3+ doped La2Zr2O7

    NASA Astrophysics Data System (ADS)

    Pokhrel, Madhab; Brik, Mikhail; Mao, Yuanbing

    2015-03-01

    Herein, we will be presenting the dopant (Eu) concentration dependent high density La2Zr2O7 nanoparticles for optical and X-ray scintillation applications by use of X - ray diffraction, Raman, FTIR, scanning electron microscope (SEM), transmission electron microscopy (TEM), optically and X-ray excited photoluminescence (PL). Several theoretical methods have been used in order to investigate the structural, electronic, optical, elastic, dynamic properties of Eu doped La2Zr2O7. It is observed that Eu: La2Zr2O7 shows an intense red luminescence under 258, 322, 394 and 465 nm excitation. The optical intensity of Eu: La2Zr2O7 depends on the dopant concentration of Eu3+. Following high energy excitation with X-rays, Eu: La2Zr2O7 shows an atypical Eu PL response (scintillation) with a red emission. The intense color emission of Eu obtained under 258 nm excitation, the X-ray induced luminescence property along with reportedly high density of La2Zr2O7, makes these nanomaterials attractive for optical and X-ray applications. The authors thank the support from the Defense Threat Reduction Agency (DTRA) of the U.S. Department of Defense (Award #HDTRA1-10-1-0114).

  19. Measurement of the 7p{sup 2}P{sub 3/2} Level Lifetime in Atomic Francium

    SciTech Connect

    Zhao, W.Z.; Simsarian, J.E.; Orozco, L.A.; Shi, W.; Sprouse, G.D.

    1997-06-01

    We present the first measurement of an atomic radiative lifetime in Fr. We use a time-correlated single photon counting technique with a cold sample of {sup 210}Fr atoms in a magneto-optic trap. The results are a precision experimental test of the atomic many-body perturbation theory applied to the heaviest alkali. The lifetime for the 7p {sup 2}P{sub 3/2} level of 21.02(16) ns gives a value for the reduced transition matrix element between the levels 7s {sup 2}S{sub 1/2} {r_arrow} 7p {sup 2}P{sub 3/2} of 5.898(22)a{sub {infinity}} atomic units. {copyright} {ital 1997} {ital The American Physical Society}

  20. Ultra-thin YBa2Cu3O7-x films with high critical current density

    NASA Astrophysics Data System (ADS)

    Lyatti, M.; Savenko, A.; Poppe, U.

    2016-06-01

    Despite impressive progress in the development of superconducting nanowire single-photon detectors (SNSPD), the main obstacle for the widespread use of such detectors is the low operating temperature required for low-temperature superconductors. The very attractive idea of increasing the operating temperature using high-temperature superconductors for SNSPD fabrication is problematic due to the insufficient quality of ultra-thin films from high-temperature superconductors, which is one of the key requirements for the single-photon detection by superconducting nanowires. In this work, we demonstrate the possibility of fabricating ultra-thin YBa2Cu3O7-x films on SrTiO3 substrates with a surface flatness of ±1 unit cell and a high critical current density up to 14 MA cm-2 at T = 78 K. The critical current density of ultra-thin films had very low value in the first three unit cell layers adjacent to the substrate and reached nearly the bulk value at the fifth layer. 97% of the superconducting current is carried by only two upper layers of a 5-unit-cell thick YBa2Cu3O7-x film. Due to such superconducting current distribution over the film thickness and good surface flatness 5-unit-cell thick YBa2Cu3O7-x films could be promising for the fabrication of single-photon detectors.

  1. Superconducting YBa 2Cu 3O 7-δ films on SrTiO 3 by electrodeposition process

    NASA Astrophysics Data System (ADS)

    Machado, A. J. S.; Moehlecke, S.; Kopelevich, Y.; Robin, A.; dos Santos, C. A. M.

    An ac electrodeposition (ED) process to obtain good quality YBa 2Cu 3O 7-δ (YBCO) high-temperature superconductor (HTS) films was developed. These films were deposited on SrTiO 3 (100) single crystal substrates previously coated with a thin silver layer (800 Å) that was deposited by chemical reduction. A small amount of Ag (0.7% in weight) added to the electrolyte bath was shown to improve the quality of the deposited films. YBCO films after an appropriate heat treatment present single phase material with an onset T c ∼ 90 K, ΔT c ∼ 2 K, homogeneous grain morphology and strong biaxial texture. Transport measurements show a metallic behavior in the normal state and a self-field critical current densities ∼ 10 5 A/cm 2 at 4.2 K and ∼ 10 4 A/cm 2 at 77K.

  2. Structural investigation of the bilayer iridate Sr3Ir2O7

    NASA Astrophysics Data System (ADS)

    Hogan, Tom; Bjaalie, Lars; Zhao, Liuyan; Belvin, Carina; Wang, Xiaoping; Van de Walle, Chris G.; Hsieh, David; Wilson, Stephen D.

    2016-04-01

    A complete structural solution of the bilayer iridate compound Sr3Ir2O7 presently remains outstanding. Previously reported structures for this compound vary and all fail to explain weak structural violations observed in neutron scattering measurements as well as the presence of a net ferromagnetic moment in the basal plane. In this paper, we present single crystal neutron diffraction and rotational anisotropy second harmonic generation measurements unveiling a lower, monoclinic symmetry inherent to Sr3Ir2O7 . Combined with density functional theory, our measurements identify the correct structural space group as No. 15 (C2/c) and provide clarity regarding the local symmetry of Ir4 + cations within this spin-orbit Mott material.

  3. Domains and ferroelectric switching pathways in Ca3Ti2O7 from first principles

    NASA Astrophysics Data System (ADS)

    Nowadnick, Elizabeth A.; Fennie, Craig J.

    2016-09-01

    Hybrid improper ferroelectricity, where an electrical polarization can be induced via a trilinear coupling to two nonpolar structural distortions of different symmetries, recently was demonstrated experimentally in the n =2 Ruddlesden-Popper compound Ca3Ti2O7 . In this paper we use group theoretic methods and first-principles calculations to identify possible ferroelectric switching pathways in Ca3Ti2O7 . We identify low-energy paths that reverse the polarization direction by switching via an orthorhombic twin domain or via an antipolar structure. We also introduce a chemically intuitive set of local order parameters to give insight into how these paths are relevant to ferroelectric switching nucleated at domain walls. Our findings suggest that switching may proceed via more than one mechanism in this material.

  4. Disordered dimer state in electron-doped Sr3Ir2O7

    NASA Astrophysics Data System (ADS)

    Hogan, Tom; Dally, Rebecca; Upton, Mary; Clancy, J. P.; Finkelstein, Kenneth; Kim, Young-June; Graf, M. J.; Wilson, Stephen D.

    2016-09-01

    Spin excitations are explored in the electron-doped spin-orbit Mott insulator (Sr1-xLax) 3Ir2O7 . As this bilayer square lattice system is doped into the metallic regime, long-range antiferromagnetism vanishes, yet a spectrum of gapped spin excitation remains. Excitation lifetimes are strongly damped with increasing carrier concentration, and the energy-integrated spectral weight becomes nearly momentum independent as static spin order is suppressed. Local magnetic moments, absent in the parent system, grow in metallic samples and approach values consistent with one J =1/2 impurity per electron doped. Our combined data suggest that the magnetic spectra of metallic (Sr1-xLax) 3Ir2O7 are best described by excitations out of a disordered dimer state.

  5. Synthesis and luminescent properties of rare earth (Sm3+ and Eu3+) Doped Gd2Ti2O7 pyrochlore nanopowders

    NASA Astrophysics Data System (ADS)

    Ćulubrk, Sanja; Antić, Željka; Marinović-Cincović, Milena; Ahrenkiel, Phillip S.; Dramićanin, Miroslav D.

    2014-11-01

    This work describes the synthesis and photoluminescent properties of rare earth (Sm3+ and Eu3+) doped Gd2Ti2O7 pyrochlore nanopowders. Pure-phase rare earth-doped Gd2Ti2O7 nanoparticles of approximately 20-50 nm in diameter, as evidenced from X-ray diffraction and electron microscopy analysis, are produced via the mixed metal-citric acid complex method. A temperature of 880 °C is identified for the formation of the crystalline pyrochlore phase, based on a differential thermal analysis of Gd2Ti2O7 precursor gels. From photoluminescence excitation and emission spectra, measured at 10 K and room temperature, the energy levels of Sm3+ and Eu3+ ions in Gd2Ti2O7 nanoparticles are obtained. The dependence of luminescence emission intensity and emission decays on rare earth concentration are measured and discussed. The strongest Sm3+ orange-reddish emission is observed for samples containing 2.5 at.% of Sm3+ ions, while in the case of Eu3+, the most intense emission is found for 15 at.% Eu3+ doping. The 4G5/2 level lifetime decreases with an increase in Sm3+ concentration, from about 5 ms (for 0.1-0.2 at.% of Sm3+) to 2.4 ms (for 2.5 at.% of Sm3+). With an increase in Eu3+ concentration in the Gd2Ti2O7 nanoparticles, the Eu3+5D0 level lifetime decreases from ∼5.9 ms (for 0.5 at.% of Sm3+) to 3.1 ms (for 15 at.% of Sm3+).

  6. Synthesis of YBa2CU3O7 using sub-atmospheric processing

    DOEpatents

    Wiesmann, Harold; Solovyov, Vyacheslav

    2004-09-21

    The present invention is a method of forming thick films of crystalline YBa.sub.2 Cu.sub.3 O.sub.7 that includes forming a precursor film comprising barium fluoride (BaF.sub.2), yttrium (Y) and copper (Cu). The precursor film is heat-treated at a temperature above 500.degree. C. in the presence of oxygen, nitrogen and water vapor at sub-atmospheric pressure to form a crystalline structure. The crystalline structure is then annealed at about 500.degree. C. in the presence of oxygen to form the crystalline YBa.sub.2 Cu.sub.3 O.sub.7 film. The YBa.sub.2 Cu.sub.3 O.sub.7 film formed by this method has a resistivity of from about 100 to about 600 .mu.Ohm-cm at room temperature and a critical current density measured at 77 K in a magnetic field of 1 Tesla of about 1.0.times.10.sup.5 Ampere per square centimeter (0.1 MA/cm.sup.2) or greater.

  7. Pressure dependence of the structure and electronic properties of Sr3Ir2O7

    NASA Astrophysics Data System (ADS)

    Donnerer, C.; Feng, Z.; Vale, J. G.; Andreev, S. N.; Solovyev, I. V.; Hunter, E. C.; Hanfland, M.; Perry, R. S.; Rønnow, H. M.; McMahon, M. I.; Mazurenko, V. V.; McMorrow, D. F.

    2016-05-01

    We study the structural evolution of Sr3Ir2O7 as a function of pressure using x-ray diffraction. At a pressure of 54 GPa at room temperature, we observe a first-order structural phase transition, associated with a change from tetragonal to monoclinic symmetry and accompanied by a 4% volume collapse. Rietveld refinement of the high-pressure phase reveals a novel modification of the Ruddlesden-Popper structure, which adopts an altered stacking sequence of the perovskite bilayers. As the positions of the oxygen atoms could not be reliably refined from the data, we use density functional theory (local-density approximation+U +spin orbit) to optimize the crystal structure and to elucidate the electronic and magnetic properties of Sr3Ir2O7 at high pressure. In the low-pressure tetragonal phase, we find that the in-plane rotation of the IrO6 octahedra increases with pressure. The calculations further indicate that a bandwidth-driven insulator-metal transition occurs at ˜20 GPa, along with a quenching of the magnetic moment. In the high-pressure monoclinic phase, structural optimization resulted in complex tilting and rotation of the oxygen octahedra and strongly overlapping t2 g and eg bands. The t2 g bandwidth renders both the spin-orbit coupling and electronic correlations ineffectual in opening an electronic gap, resulting in a robust metallic state for the high-pressure phase of Sr3Ir2O7 .

  8. Multiple Metamagnetic Quantum Criticality in Sr_{3}Ru_{2}O_{7}.

    PubMed

    Tokiwa, Y; Mchalwat, M; Perry, R S; Gegenwart, P

    2016-06-01

    Bilayer strontium ruthenate Sr_{3}Ru_{2}O_{7} displays pronounced non-Fermi liquid behavior at magnetic fields around 8 T, applied perpendicular to the ruthenate planes, which previously has been associated with an itinerant metamagnetic quantum critical end point (QCEP). We focus on the magnetic Grüneisen parameter Γ_{H}, which is the most direct probe to characterize field-induced quantum criticality. We confirm quantum critical scaling due to a putative two-dimensional QCEP near 7.845(5) T, which is masked by two ordered phases A and B, identified previously by neutron scattering. In addition, we find evidence for a QCEP at 7.53(2) T and determine the quantum critical regimes of both instabilities and the effect of their superposition. PMID:27314732

  9. Synthesis and characterization of p-type conductivity dopant 2-(3-(adamantan-1-yl)propyl)-3,5,6-trifluoro-7,7,8,8-tetracyanoquinodimethane

    SciTech Connect

    Rainbolt, James E.; Koech, Phillip K.; Polikarpov, Evgueni; Swensen, James S.; Cosimbescu, Lelia; Von Ruden, Amber L.; Wang, Liang; Sapochak, Linda S.; Padmaperuma, Asanga B.; Gaspar, Daniel J.

    2013-01-22

    We report the synthesis and characterization of 2-(3-(adamantan-1-yl)propyl)-3,5,6-trifluoro-7,7,8,8-tetracyanoquinodimethane (F3TCNQ-Ad1), a substituted analog of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), designed for p-type conductivity doping. The dopant is designed as a model for substituted alternatives to F4TCNQ that maintain similar electronic properties with the goal of engineering dopants with superior fabrication characteristics over F4TCNQ. We describe the design strategy for F3TCNQ-Ad1 based on molecular modeling predictions that substitution of a single fluorine atom of F4TCNQ has little effect on the electronic properties of the molecule. Photophysical and electrochemical characterization reveal that the adamantyl substituent in F3TCNQ-Ad1 does not significantly alter the electronic properties of the substituted dopant relative to F4TCNQ. Unfortunately, F3TCNQ-Ad1 degrades under standard sublimation conditions, preventing sublimation deposition processing. Instead, hole-only devices were made via solution-processing of the p-doped films with the structure glass/ITO/2.3 x103Å PVK:(MTDATA:dopant)/2.0x102Å Au/1.0x103Å Al, where dopant is either F4TCNQ or F3TCNQ-Ad1. We demonstrate that F3TCNQ-Ad1 increased the conductivity of the films by at least 1,000 times compared to an undoped device.

  10. Relations structurales entre U 3O 8 et quelques fluorures mixtes de formules M2M' 3F 11, MM' 2F 7 et MM' 3F 10

    NASA Astrophysics Data System (ADS)

    Aléonard, S.; Le Fur, Y.; Champarnaud-Mesjard, J. C.; Frit, B.; Roux, M. Th.

    1983-01-01

    U 3O 8 oxide, as well as M2M' 3F 11, MM' 2F 7 and MM' 3F 10 fluorides, with M = Rb, Tl, Cs, NH 4 and M' = In, Lu, Yb, Tm, is described as the regular repetition according to the … A-A-A … sequence of identical and parallel sheets of edge-and corner-sharing M'F 7 or UO 7 pentagonal bipyramids and M'F 6 octahedra. M' and U atoms are systematically located at the lattice points of a pseudohexagonal network, but in the fluorides some of these lattice points are vacant, producing hexagonal tunnels in which M atoms are located. It is shown that in the two kinds of compounds the same linear chains and M' 3X17 groups of pentagonal bipyramids are present, and that the transformation of the U 3O 8 structure into the fluorides can be achieved by an ordered substitution of some linear … UOUO … chains by … M- M- M … chains. All these structures can be described with the same structural model based on the chemical twinning principle.

  11. Pressure-Induced Confined Metal from the Mott Insulator Sr_{3}Ir_{2}O_{7}.

    PubMed

    Ding, Yang; Yang, Liuxiang; Chen, Cheng-Chien; Kim, Heung-Sik; Han, Myung Joon; Luo, Wei; Feng, Zhenxing; Upton, Mary; Casa, Diego; Kim, Jungho; Gog, Thomas; Zeng, Zhidan; Cao, Gang; Mao, Ho-Kwang; van Veenendaal, Michel

    2016-05-27

    The spin-orbit Mott insulator Sr_{3}Ir_{2}O_{7} provides a fascinating playground to explore insulator-metal transition driven by intertwined charge, spin, and lattice degrees of freedom. Here, we report high-pressure electric resistance and resonant inelastic x-ray scattering measurements on single-crystal Sr_{3}Ir_{2}O_{7} up to 63-65 GPa at 300 K. The material becomes a confined metal at 59.5 GPa, showing metallicity in the ab plane but an insulating behavior along the c axis. Such an unusual phenomenon resembles the strange metal phase in cuprate superconductors. Since there is no sign of the collapse of spin-orbit or Coulomb interactions in x-ray measurements, this novel insulator-metal transition is potentially driven by a first-order structural change at nearby pressures. Our discovery points to a new approach for synthesizing functional materials. PMID:27284666

  12. Pressure-Induced Confined Metal from the Mott Insulator Sr3 Ir2 O7

    NASA Astrophysics Data System (ADS)

    Ding, Yang; Yang, Liuxiang; Chen, Cheng-Chien; Kim, Heung-Sik; Han, Myung Joon; Luo, Wei; Feng, Zhenxing; Upton, Mary; Casa, Diego; Kim, Jungho; Gog, Thomas; Zeng, Zhidan; Cao, Gang; Mao, Ho-kwang; van Veenendaal, Michel

    2016-05-01

    The spin-orbit Mott insulator Sr3Ir2O7 provides a fascinating playground to explore insulator-metal transition driven by intertwined charge, spin, and lattice degrees of freedom. Here, we report high-pressure electric resistance and resonant inelastic x-ray scattering measurements on single-crystal Sr3Ir2O7 up to 63-65 GPa at 300 K. The material becomes a confined metal at 59.5 GPa, showing metallicity in the a b plane but an insulating behavior along the c axis. Such an unusual phenomenon resembles the strange metal phase in cuprate superconductors. Since there is no sign of the collapse of spin-orbit or Coulomb interactions in x-ray measurements, this novel insulator-metal transition is potentially driven by a first-order structural change at nearby pressures. Our discovery points to a new approach for synthesizing functional materials.

  13. Oxygen Deficient YBa 2 Cu 3 O 7-δ : Two Superconducting Phases

    NASA Astrophysics Data System (ADS)

    Stankowski, J.; ¦L+/-Zak, A.; Kempiñski, W.; Andrzejewski, B.; Reichel, B.; Plesch, G.

    2003-03-01

    A set of oxygen deficient powder and granular samples of YBa 2 Cu 3 O 7-δ ceramics was studied by means of thermogravimetric and magnetically modulated microwave absorption methods. Especially the last method has turned out to be a powerful method, which was used to determine the dependence of critical temperature T c on the oxygen parameter δ. Using these methods it has been shown that the removing of oxygen evokes the inhomogeneous oxygen distribution in the samples and a change in carrier concentration till to the loss of superconducting properties. A superconducting phase with T_c=60 K, which occurs in oxygen deficient YBa 2 Cu 3 O 7-δ sample, is an unstable phase.

  14. Synthesis and structural chemistry of Au(III)-substituted Ba2YCu3O(7-delta)

    NASA Technical Reports Server (NTRS)

    Hepp, A. F.; Gaier, J. R.; Pouch, J. J.; Banerjea, A.; Hambourger, P. D.

    1988-01-01

    Gold-substituted superconductors, Ba2Y(Au(x)Cu(1-x))3O(7-delta) (x = 0-0.1) were synthesized. For x = 0.1, there was no change in the a and b lattice parameters (a = 3.826 A and b = 3.889 A) but a 0.06 A c axis expansion to 11.75 A was observed. Substituted gold is found to be trivalent by XPS. Replacing Cu(1) in the copper oxide chain with a slight reordering of oxygen is consistent with c axis expansion. The formal charge of the site remains trivalent; remaining Cu in the chains may be reduced resulting in an oxygen stoichiometry is less than or equal to 7. A small effect on T(sub c)(89 K for x = 0.10) is observed upon gold substitution.

  15. Phase evolution studies in CaZrTi2O7-RE2Ti2O7 (RE = Nd3+, Sm3+) system: Futuristic ceramic host matrices for nuclear waste immobilization

    NASA Astrophysics Data System (ADS)

    Jafar, M.; Achary, S. N.; Tyagi, A. K.

    2014-04-01

    Series of compositions with general stoichiometry as Ca1-xZr1-xRE2xTi2O7 (RE = Nd3+, Sm3+) were prepared by solid state reaction and characterized by powder x-ray diffraction technique to unravel the phase fields in the title systems. The phase fields in CaZrTi2O7-Nd2Ti2O7 and CaZrTi2O7-Sm2Ti2O7 systems differed significantly at the rareearth rich regions. The common phase fields like zirconolite-2M, zirconolite-4M, cubic perovskite are observed at the zirconolite rich regions of both systems. Depending on the structure of RE2Ti2O7 phase, the cubic pyrochlore or monoclinic RE2Ti2O7 phases are observed in the studied system. The observed phase fields in these two systems indicate ionic radius of the rare-earth ion has a dominating role in the phase relations. Further details of the phases and their homogeneity are explained in the text of the manuscript.

  16. Critical points in heavy ion irradiated untwinned YBa(2)Cu3O(7-delta) crystals

    PubMed

    Kwok; Olsson; Karapetrov; Paulius; Moulton; Hofman; Crabtree

    2000-04-17

    The critical points in untwinned YBa(2)Cu(3)O(7-delta) crystals with dilute columnar defects are investigated. We find a convergence of a first order vortex melting line with an irreversibility line associated with the onset of the Bose glass critical regime at the lower critical point. In addition, we find that columnar defects raise the upper critical point, implying that vortex line meandering is a basic feature controlling its position.

  17. Discovery and optimization of 7-aminofuro[2,3-c]pyridine inhibitors of TAK1.

    PubMed

    Hornberger, Keith R; Berger, Dan M; Crew, Andrew P; Dong, Hanqing; Kleinberg, Andrew; Li, An-Hu; Medeiros, Matthew R; Mulvihill, Mark J; Siu, Kam; Tarrant, James; Wang, Jing; Weng, Felix; Wilde, Victoria L; Albertella, Mark; Bittner, Mark; Cooke, Andrew; Gray, Michael J; Maresca, Paul; May, Earl; Meyn, Peter; Peick, William; Romashko, Darlene; Tanowitz, Michael; Tokar, Brianna

    2013-08-15

    The discovery and potency optimization of a series of 7-aminofuro[2,3-c]pyridine inhibitors of TAK1 is described. Micromolar hits taken from high-throughput screening were optimized for biochemical and cellular mechanistic potency to ~10nM, as exemplified by compound 12az. Application of structure-based drug design aided by co-crystal structures of TAK1 with inhibitors significantly shortened the number of iterations required for the optimization. PMID:23850198

  18. Radiolysis of 2,3,7,8-tetrachlorodibenzo- p-dioxin in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Mamedov, Kh. F.; Aliev, A. G.; Mamedova, N. A.; Badalova, A. R.

    2015-09-01

    The conversion of 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) in diluted aqueous solutions at different absorbed doses of ionizing radiation using the 60Co source is studied. The radiochemical yield of TCDD conversion is (0.3-1.5) × 10-5 molecules/100 eV for solutions with 0.2-2 μg/L TCDD in open cells and 2.4 × 10-5 molecules/100 eV for air-sparged 2 μg/L TCDD solutions. It is demonstrated that the absorbed dose of ionizing radiation (25 kGy) lowers the TCDD concentration in oxygen-containing aqueous solutions virtually to zero.

  19. Synthesis and preliminary evaluation of 5,7-dimethyl-2-aryl-3H-pyrrolizin-3-ones as angiogenesis inhibitors.

    PubMed

    Kirk, Nicholas S; Bezos, Anna; Willis, Anthony C; Sudta, Pichit; Suksamrarn, Sunit; Parish, Christopher R; Ranson, Marie; Kelso, Michael J

    2016-04-01

    Sunitinib (Sutent®) is a receptor tyrosine kinase (RTK) and angiogenesis inhibitor approved for the treatment of renal cell carcinomas, gastrointestinal stromal tumours and pancreatic neuroendocrine tumours. A key structural motif retained throughout medicinal chemistry efforts during sunitinib's development was the indoline-2-one group. In the search for new anti-angiogenic scaffolds, we previously reported that non-indoline-2-one-based derivatives of semaxanib (SU5416, a structurally simpler sunitinib predecessor that underwent Phase III trials) are active as angiogenesis inhibitors, indicating that the group is not essential for activity. This Letter describes the synthesis and structure-activity relationships of another class of non-indoline-2-one angiogenesis inhibitors related to sunitinib/semaxanib; the 5,7-dimethyl-2-aryl-3H-pyrrolizin-3-ones. A focussed library of 19 analogues was prepared using a simple novel process, wherein commercially available substituted arylacetic acids activated with an amide coupling reagent (HBTU) were reacted with the potassium salt of 3,5-dimethyl-1H-pyrrole-2-carbaldehyde in one-pot. Screening of the library using a cell-based endothelial tube formation assay identified 6 compounds with anti-angiogenesis activity. Two of the compounds were advanced to the more physiologically relevant rat aortic ring assay, where they showed similar inhibitory effects to semaxanib at 10μg/mL, confirming that 5,7-dimethyl-2-aryl-3H-pyrrolizin-3-ones represent a new class of angiogenesis inhibitors. PMID:26912111

  20. 40 CFR 721.5262 - 2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[substituted] amino]-1,3,5-triazin-2-yl]amino]-4...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...,7-Naphthalenedisulfonic acid, 5- amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3- -, trisodium salt... identified generically as 2,7-Naphthalenedisulfonic acid, 5- amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 2,7-Naphthalenedisulfonic acid,...

  1. 40 CFR 721.5262 - 2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[substituted] amino]-1,3,5-triazin-2-yl]amino]-4...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...,7-Naphthalenedisulfonic acid, 5- amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3- -, trisodium salt... identified generically as 2,7-Naphthalenedisulfonic acid, 5- amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3... 40 Protection of Environment 32 2012-07-01 2012-07-01 false 2,7-Naphthalenedisulfonic acid,...

  2. 40 CFR 721.5262 - 2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[substituted] amino]-1,3,5-triazin-2-yl]amino]-4...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...,7-Naphthalenedisulfonic acid, 5- amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3- -, trisodium salt... identified generically as 2,7-Naphthalenedisulfonic acid, 5- amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3... 40 Protection of Environment 31 2011-07-01 2011-07-01 false 2,7-Naphthalenedisulfonic acid,...

  3. 40 CFR 721.5262 - 2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[substituted] amino]-1,3,5-triazin-2-yl]amino]-4...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...,7-Naphthalenedisulfonic acid, 5- amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3- -, trisodium salt... identified generically as 2,7-Naphthalenedisulfonic acid, 5- amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 2,7-Naphthalenedisulfonic acid,...

  4. Phononic Structure Relationships in the Subgroup Phases of Ferroelectric Ca3Mn2O7

    NASA Astrophysics Data System (ADS)

    Shoko, Elvis; Al Dawood, Eman; Schwingenschlogl, Udo

    The Ruddlesden-Popper (RP) compound, Ca3Mn2O7, exhibits hybrid improper ferroelectric (FE) behavior in its A21am phase. However, a new phase (space group Acaa), co-existing with the FE phase (200-320 K) and exhibiting negative thermal expansion (NTE) was recently discovered. This discovery highlighted the complexity of the phase relationships in the subgroup structure of Ca3Mn2O7. Successful exploitation of RP compounds for FE applications depends on a clear understanding of the phononic relationships among the different relevant subgroup phases. Accordingly, we have used density functional theory (DFT) to map out the total energy landscape for the principal subgroup phases relative to the tetragonal phase. In order to elucidate the interrelationships of the soft phonon modes among the different subgroup phases, we performed lattice dynamics and quasi-harmonic approximation calculations. In addition, the latter calculations enabled us to extract mode Gruneisen parameters leading to new insights into the NTE behavior of Ca3Mn2O7. The implications of our findings are discussed in the context of the potential of RP compounds as FE materials.

  5. Is 2,3,7,8-TCDD (dioxin) a carcinogen for humans

    SciTech Connect

    Ayres, S.M.; Webb, K.B.; Evans, R.G.; Mikes, J.

    1985-10-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has suddenly become the focal point of controversy over the relationship of chemical waste to human health. Specific concern exists regarding its potential association with human malignancy. Subcellular, cellular, and whole-animal experiments suggest that TCDD exerts much of its activity by inducing enzymes that protect the intact organism from the assault of environmental contamination. TCDD is a potent inducer of aryl hydrocarbon hydroxylase, although wide variations between species do exist. Conventional tests for mutagenicity have produced conflicting results. Animal experiments have shown the development of tumors following chronic low level ingestion of TCDD. The human evidence regarding the potential carcinogencity of TCDD comes from occupational, military and environmental exposures. Several studies have come out of Sweden suggesting an association between sarcoma and exposure to herbicides. Although there is little solid evidence that 2,3,7,8-TCDD produces substantial chronic disability or premature death in man, a significant body of experimental evidence for its carcinogenicity makes it likely that a small number of human malignancies may be due to its action. Since 2,3,7,8-TCDD is an unwanted contaminant it could be eliminated with little measurable consequence.

  6. Is 2,3,7,8-TCDD (dioxin) a carcinogen for humans?

    PubMed Central

    Ayres, S M; Webb, K B; Evans, R G; Mikes, J

    1985-01-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has suddenly become the focal point of controversy over the relationship of chemical waste to human health. Specific concern exists regarding its potential association with human malignancy. Subcellular, cellular, and whole-animal experiments suggest that TCDD exerts much of its activity by inducing enzymes that protect the intact organism from the assault of environmental contamination. TCDD is a potent inducer of aryl hydrocarbon hydroxylase, although wide variations between species do exist. Conventional tests for mutagenicity have produced conflicting results. Animal experiments have shown the development of tumors following chronic low level ingestion of TCDD. The human evidence regarding the potential carcinogencity of TCDD comes from occupational, military and environmental exposures. Several studies have come out of Sweden suggesting an association between sarcoma and exposure to herbicides. Although there is little solid evidence that 2,3,7,8-TCDD produces substantial chronic disability or premature death in man, a significant body of experimental evidence for its carcinogenicity makes it likely that a small number of human malignancies may be due to its action. Since 2,3,7,8-TCDD is an unwanted contaminant it could be eliminated with little measurable consequence. PMID:3910419

  7. 40 CFR 721.10467 - 2-Propenoic acid, 3-hydroxytricyclo[3.3.1.13,7]dec-1-yl ester.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for...)(i), (a)(2)(iii), (a)(3), (a)(4) (National Institute for Occupational Safety and Health...

  8. Magnetization studies of YBa 2Cu 3O 7-x irradiated by fast neutrons

    NASA Astrophysics Data System (ADS)

    Wisniewski, A.; Baran, M.; Przysłupski, P.; Szymczak, H.; Pajaczkowska, A.; Pytel, B.; Pytel, K.

    1988-02-01

    Studies of the effect of fast neutron damage on the magnetic hysteresis of YBa 2Cu 3O 7-x ceramic samples subjected to fluence of neutrons of 2∗10 16 n/cm 2 up to 6∗10 17 n/cm 2 have been performed. irradiation up to dose of 1∗10 17 did not cause any change in the critical temperature. However it causes a strong increase of the magnetic hysteresis which is presumably connected with the creation of defects. The critical current density at 77 K in H = 10 k0e for the sample irradiated with the dose 1∗10 17 n/cm 2 was estimated to be 520 A/cm 2 as compared to 29 A/cm 2 for the reference non-irradiated sample, non-irradiated sample.

  9. YBa_2Cu_3O_{7-δ} : in pursuit of the ideal microstructure

    NASA Astrophysics Data System (ADS)

    Smith, D. S.; Suasmoro, S.; Lejeune, M.; Rabier, J.; Denanot, M. F.; Heintz, J. M.; Magro, C.; Bonnet, J. P.

    1992-02-01

    This paper examines the role of different factors in the microstructure of ceramic YBa2Cu3O{7-δ} with emphasis on its electrical response. In particular we discuss : 1. the effect of microstructural variations on j_c and ρ_{300}, 2. measurement of j_c, 3. the presence of minor phases and carbonates, 4. oxygen uptake and microcracks, 5. plastic deformation and related structural defects. Dans cet article, nous examinons d'une part la réponse électrique de céramiques supraconductrices massives de type YBa2Cu3O{7-δ} et d'autre part sa relation avec la microstructure. Nous présenterons successivement : 1. L'incidence de modifications microstructurales sur les valeurs de j_c et ρ_{300}, 2. les mesures expérimentales de j_c, 3. la présence de phases minoritaires et de carbonates, 4. la reprise d'oxygène et la microfissuration, 5. la déformation plastique et les défauts structuraux associés.

  10. Engelhauptite, KCu3(V2O7)(OH)2Cl, a new mineral species from Eifel, Germany

    NASA Astrophysics Data System (ADS)

    Pekov, Igor V.; Siidra, Oleg I.; Chukanov, Nikita V.; Yapaskurt, Vasiliy O.; Britvin, Sergey N.; Krivovichev, Sergey V.; Schüller, Willi; Ternes, Bernd

    2015-12-01

    A new mineral engelhauptite, KCu3(V2O7)(OH)2Cl, was found within cavities in nepheline basalts at the Auf'm Kopp quarry ("Schlackenkegel der Höhe 636 südöstlich Neroth" ), Daun, Eifel region, Rheinland-Pfalz, Germany. Associated minerals are volborthite, allophane, malachite, tangeite and chrysocolla; earlier minerals belonging to the primary, high-temperature parageneses are augite, mica of the phlogopite-oxyphlogopite series, sanidine, nepheline, leucite, fluorapatite and magnetite. Engelhauptite occurs as spherulites (up to 0.2 mm in diameter) and bunches consisting of rough spindle-shaped crystals elongated parallel to [0001]. The crystals are up to 0.12 mm long and up to 0.04 mm thick. Individual grains of engelhauptite are transparent, whereas their aggregates are translucent. The mineral is yellow-brown to brown, typically with an olive green hue. The luster is vitreous. Engelhauptite is brittle, cleavage is not observed, fracture is uneven. D calc = 3.86 g cm-3. Engelhauptite is optically uniaxial (+), ω = 1.978(4), ɛ = 2.021(4). Chemical data (wt.%, electron-microprobe, H2O by difference) are as following: K2O 9.63, FeO 0.05, NiO 0.29, CuO 46.11, Al2O3 0.24, V2O5 34.92, SO3 0.79, Cl 5.94, H2Ocalc 3.37, O = Cl2 -1.34, total 100.00. The empirical formula, based on 10 (O + OH + Cl) apfu, is K1.05(Cu2.97Al0.02Ni0.02)Σ3.01(V1.97S0.05)Σ2.02O7.23(OH)1.91Cl0.86. Engelhauptite is hexagonal, P63/ mmc, a = 5.922(2), c = 14.513(5) Å, V = 440.78(3) Å3 and Z = 2. The eight strongest reflections of the powder X-ray diffraction pattern [ d,Å( I) ( hkl)] are: 7.32(98) (002), 4.224(17) (102), 2.979(100) (104, 110), 2.759(19) (112), 2.565(18) (200), 2.424(18) (202), 1.765(16) (206) and 1.481(14) (208, 220). The crystal structure of engelhauptite has been solved from the single-crystal X-ray diffraction data and refined to R = 0.090 on the basis of 135 unique observed reflections. The structure is based upon the [Cu2+ 3(V2O7)(OH)2]0 framework formed by the linkage

  11. Bilayer splitting and wave functions symmetry in Sr3Ir2O7

    NASA Astrophysics Data System (ADS)

    Moreschini, L.; Moser, S.; Ebrahimi, A.; Dalla Piazza, B.; Kim, K. S.; Boseggia, S.; McMorrow, D. F.; Rønnow, H. M.; Chang, J.; Prabhakaran, D.; Boothroyd, A. T.; Rotenberg, E.; Bostwick, A.; Grioni, M.

    2014-05-01

    The influence of dimensionality on the electronic properties of layered perovskite materials remains an outstanding issue. We address it here for Sr3Ir2O7, the bilayer compound of the iridate Srn+1IrnO3n+1 series. By angle-resolved photoemission spectroscopy we show that in this material the interlayer coupling is large and that the intercell coupling is, conversely, negligible. From a detailed mapping of the bilayer splitting, and from the intensity modulation of the bonding and antibonding bands with photon energy, we establish differences and similarities with the prominent case of the bilayer superconducting cuprates.

  12. Reduced reactivity to air on HF-treated YBa2Cu3O7 - x surfaces

    NASA Astrophysics Data System (ADS)

    Vasquez, R. P.; Hunt, B. D.; Foote, M. C.

    1989-06-01

    Treatment of YBa2Cu3O7-x films with a nonaqueous solution of HF in absolute ethanol results in the formation of an oxyfluoride with relative Y:Ba:Cu concentrations of 1:4:3 on the surface, as determined by x-ray photoelectron spectroscopy. The passivation properties of chemically treated films were tested by monitoring the growth of the high binding energy O 1s peak, associated with nonsuperconducting surface species, as a function of air exposure time, for both HF-treated and untreated films. The native oxyfluoride is shown to reduce the reactivity of the superconductor to air.

  13. Retigabine, a Kv7.2/Kv7.3-Channel Opener, Attenuates Drug-Induced Seizures in Knock-In Mice Harboring Kcnq2 Mutations

    PubMed Central

    Ihara, Yukiko; Tomonoh, Yuko; Deshimaru, Masanobu; Zhang, Bo; Uchida, Taku; Ishii, Atsushi; Hirose, Shinichi

    2016-01-01

    The hetero-tetrameric voltage-gated potassium channel Kv7.2/Kv7.3, which is encoded by KCNQ2 and KCNQ3, plays an important role in limiting network excitability in the neonatal brain. Kv7.2/Kv7.3 dysfunction resulting from KCNQ2 mutations predominantly causes self-limited or benign epilepsy in neonates, but also causes early onset epileptic encephalopathy. Retigabine (RTG), a Kv7.2/ Kv7.3-channel opener, seems to be a rational antiepileptic drug for epilepsies caused by KCNQ2 mutations. We therefore evaluated the effects of RTG on seizures in two strains of knock-in mice harboring different Kcnq2 mutations, in comparison to the effects of phenobarbital (PB), which is the first-line antiepileptic drug for seizures in neonates. The subjects were heterozygous knock-in mice (Kcnq2Y284C/+ and Kcnq2A306T/+) bearing the Y284C or A306T Kcnq2 mutation, respectively, and their wild-type (WT) littermates, at 63–100 days of age. Seizures induced by intraperitoneal injection of kainic acid (KA, 12mg/kg) were recorded using a video-electroencephalography (EEG) monitoring system. Effects of RTG on KA-induced seizures of both strains of knock-in mice were assessed using seizure scores from a modified Racine’s scale and compared with those of PB. The number and total duration of spike bursts on EEG and behaviors monitored by video recording were also used to evaluate the effects of RTG and PB. Both Kcnq2Y284C/+ and Kcnq2A306T/+ mice showed significantly more KA-induced seizures than WT mice. RTG significantly attenuated KA-induced seizure activities in both Kcnq2Y284C/+ and Kcnq2A306T/+ mice, and more markedly than PB. This is the first reported evidence of RTG ameliorating KA-induced seizures in knock-in mice bearing mutations of Kcnq2, with more marked effects than those observed with PB. RTG or other Kv7.2-channel openers may be considered as first-line antiepileptic treatments for epilepsies resulting from KCNQ2 mutations. PMID:26910900

  14. Preparation of YBa2Cu3O7 - x films and YBa2Cu3O7 - x/Y2O3 multilayers using coevaporation and atomic oxygen

    NASA Astrophysics Data System (ADS)

    Hudner, J.; Östling, M.; Ohlsén, H.; Stolt, L.; Nordblad, P.; Ottosson, M.; Villegier, J.-C.; Moriceau, H.; Weiss, F.; Thomas, O.

    1993-03-01

    Thin layers of YBa2Cu3O7-x (YBCO) deposited on LaAlO3 substrates have been prepared in situ by coevaporation of Y, Ba, and Cu. Incorporation of oxygen was accomplished by an atomic oxygen beam source with high cracking efficiency. The total oxygen flow at the substrate could be kept low enough to permit the use of a quadrupole mass spectrometer for evaporation rate monitoring. Films were strongly c-axis oriented with rocking curve full width at half-maximum values of 0.6°. Transport measurements on patterned films yielded critical current densities of 6×106 A/cm2 at 77 K. The deposition method was demonstrated to be feasible for preparation of Y2O3/YBCO heterostructures.

  15. Interface and defect structures in YBa2Cu3O7-δ and Nb : SrTiO3 heterojunction

    NASA Astrophysics Data System (ADS)

    Fu, L. F.; Browning, N. D.; Ramadan, W.; Ogale, S. B.; Kundaliya, D. C.; Venkatesan, T.

    2007-01-01

    YBa2Cu3O7-δ thin films grown on a Nb-doped SrTiO3 substrate by a pulsed laser deposition method have been fully characterized by scanning transmission electron microscopy Z-contrast imaging and electron energy loss spectroscopy techniques. The Nb distribution was found to be uniform and unchanged across the interface, ensuring a high quality p-n junction heterointerface. We first observed the coexistence of 124 and 125 YBCO defect structure phases, appearing as planar defects in a YBCO thin film. Dispersive Y2O3 nanoparticles have also been observed in the thin film. The interaction of these defect structures and Y2O3 nanoparticles is thought to be beneficial for pinning flux through the entire film thickness.

  16. Inelastic electron scattering in the high-Tc compound YBa2Cu3O7-x

    NASA Astrophysics Data System (ADS)

    Tarrio, C.; Schnatterly, S. E.

    1988-07-01

    We have carried out inelastic electron scattering transmission measurements on the high-Tc compound YBa2Cu3O7-x in the energy range 1-100 eV. We have directly observed the free-electron plasma peak at 1.1 eV in addition to the bound electron plasmon at 25.5 eV. The interband threshold is at 2.1 eV, above which the material behaves as a typical oxide insulator.

  17. Coexistence of metallic and nonmetallic charge transport in PrBa2Cu3O7

    NASA Astrophysics Data System (ADS)

    Lee, Mark; Suzuki, Y.; Geballe, T. H.

    1995-06-01

    Magnetotransport measurements on highly oriented thin films of PrBa2Cu3O7 demonstrate a unique coexistence of nonmetallic hopping conduction with metallic Boltzmann transport. At high temperature (T>10 K) hopping transport dominates, but when the inelastic conduction freezes out at low temperature, metallic behavior can be distinguished. The hopping conduction is assigned to the CuO2 planes, while the Boltzmann transport arises from the CuO chain structure, in agreement with recent electronic-structure calculations.

  18. Surface morphology of flux-grown single crytals of YBa2Cu3O(7-delta)

    NASA Astrophysics Data System (ADS)

    Taylor, K. N. R.; Cook, P. S.; Puzzer, T.; Matthews, D. N.; Russell, G. J.

    1988-05-01

    Single crystals of YBa2Cu3O(7-delta) have been grown in a CuO-BaCuO2 flux at a temperature of 930 C and examined using SEM, XRD, and electron diffraction techniques. The observed crystal habit is predominantly square planar with the c-axis normal to the plane. Surface growth spirals are observed in approximately 25 percent of the crystallites, and in some cases extensive step decoration is exhibited. The growth surface usually involves two such spirals with Burgers vectors of the same sign. Opposed spirals have been observed in only two cases.

  19. 40 CFR 721.10710 - 4, 7-Methano-1H-indene, 3a, 4, 7, 7a-tetrahydro-, polymer with 2-methyl-1, 3-butadiene and 5-(1...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 4, 7-Methano-1H-indene, 3a, 4, 7, 7a-tetrahydro-, polymer with 2-methyl-1, 3-butadiene and 5-(1-methylethenyl)bicyclo hept-2-ene. 721.10710 Section 721.10710 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES...

  20. 3-Hy-droxy-8-oxo-3-nor-methyl-chamigrane-2,7-peroxide.

    PubMed

    Liu, Dongze

    2010-01-01

    In the title compound, C(14)H(22)O(4) (systematic name: 9-hy-droxy-1,5,5-trimethyl-1,8-epidi-oxy-spiro-[5.5]decan-2-one), which was isolated from the fermentation broth of Steccherinum ochraceum, the two six-membered rings adopt chair conformations and are bridged by a peroxide group. The hy-droxy H atom forms a three-centre cyclic inter-molecular O-H⋯(O,O') hydrogen-bonding inter-action with a peroxide and a carbonyl O-atom acceptor, forming [100] chains.

  1. Reaction of nonaqueous halogen solutions with YBa2Cu3O(7-x)

    NASA Technical Reports Server (NTRS)

    Vasquez, R. P.; Foote, M. C.; Hunt, B. D.

    1989-01-01

    The reaction of the surfaces of the new high-temperature superconductor YBa2Cu3O(7-x) with nonaqueous halogen solutions is investigated, and the species formed in the reactions are identified. Treatment of films with HF/EtOH (EtOH = HI in absolute ethanol) results in the formation of an oxyfluoride with Y:Ba:Cu relative concentrations of 1:4:3. Results of X-ray photoelectron spectroscopy of HF-treated films are consistent with the formation of CuF, a compound which does not exist in bulk form. Treatment of films with HCl/EtOH results primarily in the formation of BaCl2, with smaller amounts of YCl3, CuCl, and CuCl2. Treatment with Br2/EtOH or HBr/EtOH results in the formation of YBr3, BaBr2, and CuBr with relative concentrations of 1:4:3.

  2. Water solubility of 2,3,7,8-tetrachlorodibenzo-p-dioxin

    SciTech Connect

    Marple, L.; Brunck, R.; Throop, L.

    1986-02-01

    Vacuum deposition of a solid film onto a glass surface and equilibrium on this film with water are the basis of a method that was used to measure the water solubility of 2,3,7,8-tetrachlorodibenzo-p-dioxin. Films of both /sup 14/C-radiolabeled and unlabeled dioxin were prepared so that solubilized material could be measured by radioactivity as well as by capillary GC/LRMS techniques. The averages of solubility values for radiolabeled and unlabeled dioxin were 3.9 x 10/sup -11/ M (12.5 parts per trillion) and 6.0 x 10/sup -11/ M (19.3 parts per trillion), respectively. The solubility values lie within the values predicted from Yalkowsky's K/sub ow/-solubility equation of best fit for chlorinated hydrocarbons and the available estimates for the octanol-water partition coefficient, K/sub ow/. 11 references, 2 tables.

  3. CYP1A2 IS NOT REQUIRED FOR 2, 3, 7, 8-TETRACHLORODIBENZO-P-DIOXIN-INDUCED IMMUNOSUPPRESSION

    EPA Science Inventory

    ABSTRACT
    One of the most sensitive and reproducible immunotoxic endpoints of 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) exposure is suppression of the antibody response to sheep red blood cells (SRBCs) in mice. Immunosuppression occurs in concert with hepatomegaly and associ...

  4. Metallic Borides, La2Re3B7 and La3Re2B5, Featuring Extensive Boron-Boron Bonding.

    PubMed

    Bugaris, Daniel E; Malliakas, Christos D; Chung, Duck Young; Kanatzidis, Mercouri G

    2016-02-15

    La2Re3B7 and La3Re2B5 have been synthesized in single-crystalline form from a molten La/Ni eutectic at 1000 °C in the first example of the flux crystal growth of ternary rare-earth rhenium borides. Both compounds crystallize in their own orthorhombic structure types, with La2Re3B7 (space group Pcca) having lattice parameters a = 7.657(2) Å, b = 6.755(1) Å, and c = 11.617(2) Å, and La3Re2B5 (space group Pmma) having lattice parameters a = 10.809(2) Å, b = 5.287(1) Å, and c = 5.747(1) Å. The compounds possess three-dimensional framework structures that are built up from rhenium boride polyhedra and boron-boron bonding. La3Re2B5 features fairly common B2 dumbbells, whereas La2Re3B7 has unique one-dimensional subunits composed of alternating triangular B3 and trans-B4 zigzag chain fragments. Also observed in La3Re2B5 is an unusual coordination of B by an octahedron of La atoms. Electronic band structure calculations predict that La2Re3B7 is a semimetal, which is observed in the electrical resistivity data as measured on single crystals, with behavior obeying the Bloch-Grüneisen model and a room-temperature resistivity ρ300 K of ∼375 μΩ cm. The electronic band structure calculations also suggest that La3Re2B5 is a regular metal. PMID:26812202

  5. 40 CFR 721.5260 - 1,3,6-Naphthalenetrisulfonic acid, 7-[[2-[(aminocarbonyl)amino]- 4-[[4-[[2-[2-(ethenylsulfonyl...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...,3,6-Naphthalenetrisulfonic acid, 7- - 4- ethyl]amino]- 6-fluoro-1,3,5-triazin-2-yl]amino]phenyl]azo... substance identified as 1,3,6-Naphthalenetrisulfonic acid, 7- -4- ethyl]amino]-6-fluoro-1,3,5-triazin-2-yl... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 1,3,6-Naphthalenetrisulfonic acid,...

  6. 40 CFR 721.5260 - 1,3,6-Naphthalenetrisulfonic acid, 7-[[2-[(aminocarbonyl)amino]- 4-[[4-[[2-[2-(ethenylsulfonyl...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...,3,6-Naphthalenetrisulfonic acid, 7- - 4- ethyl]amino]- 6-fluoro-1,3,5-triazin-2-yl]amino]phenyl]azo... substance identified as 1,3,6-Naphthalenetrisulfonic acid, 7- -4- ethyl]amino]-6-fluoro-1,3,5-triazin-2-yl... 40 Protection of Environment 31 2011-07-01 2011-07-01 false 1,3,6-Naphthalenetrisulfonic acid,...

  7. 40 CFR 721.5260 - 1,3,6-Naphthalenetrisulfonic acid, 7-[[2-[(aminocarbonyl)amino]- 4-[[4-[[2-[2-(ethenylsulfonyl...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...,3,6-Naphthalenetrisulfonic acid, 7- - 4- ethyl]amino]- 6-fluoro-1,3,5-triazin-2-yl]amino]phenyl]azo... substance identified as 1,3,6-Naphthalenetrisulfonic acid, 7- -4- ethyl]amino]-6-fluoro-1,3,5-triazin-2-yl... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 1,3,6-Naphthalenetrisulfonic acid,...

  8. 40 CFR 721.5260 - 1,3,6-Naphthalenetrisulfonic acid, 7-[[2-[(aminocarbonyl)amino]- 4-[[4-[[2-[2-(ethenylsulfonyl...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...,3,6-Naphthalenetrisulfonic acid, 7- - 4- ethyl]amino]- 6-fluoro-1,3,5-triazin-2-yl]amino]phenyl]azo... substance identified as 1,3,6-Naphthalenetrisulfonic acid, 7- -4- ethyl]amino]-6-fluoro-1,3,5-triazin-2-yl... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 1,3,6-Naphthalenetrisulfonic acid,...

  9. 40 CFR 721.5260 - 1,3,6-Naphthalenetrisulfonic acid, 7-[[2-[(aminocarbonyl)amino]- 4-[[4-[[2-[2-(ethenylsulfonyl...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...,3,6-Naphthalenetrisulfonic acid, 7- - 4- ethyl]amino]- 6-fluoro-1,3,5-triazin-2-yl]amino]phenyl]azo... substance identified as 1,3,6-Naphthalenetrisulfonic acid, 7- -4- ethyl]amino]-6-fluoro-1,3,5-triazin-2-yl... 40 Protection of Environment 32 2012-07-01 2012-07-01 false 1,3,6-Naphthalenetrisulfonic acid,...

  10. Oxi-nitrate synthesis of non-carbonated YBa 2Cu 3O 7-δ powders

    NASA Astrophysics Data System (ADS)

    Heintz, J. M.; Dardant, A.

    1997-02-01

    A new synthesis route of YBa 2Cu 3O 7-δ (YBCO) which does not involve any carbon contamination during the process is presented and discussed. Barium is introduced as a nitrate and yttrium and copper as oxides in the starting mixture. Influence of two calcination environments, oxygen and argon, is studied. In both cases, the first stage involves the formation of Ba 2Cu 3O 5+ x. Under argon atmosphere, the temperature of synthesis of YBCO is decreased by 200°C. Y 2BaCuO 5 was also formed during the process and appeared difficult to remove. Presence of Y 2BaCuO 5 was attributed to the reaction between Y 2O 3+2BaCuO 2 when oxygen was used while it resulted from YBCO decomposition from 800°C under low oxygen partial pressure. A two step process was finally proposed involving a first stage under argon to favour YBCO formation at low temperature and a second stage at 900°C under oxygen to promote YBCO synthesis. A fine and pure powder was so obtained.

  11. Metabolism and disposition of 2,3,7,8-tetrachlorodibenzo-p-dioxin in guinea pigs

    SciTech Connect

    Olson, J.R.

    1986-09-15

    Marked interspecies variability exists in the acute toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), with the guinea pig being the mammalian species most sensitive to the acute toxicity of TCDD. The metabolism and disposition of TCDD was investigated in guinea pigs for 45 days following a single exposure to purified (/sup 3/H)TCDD (0.56 microgram/kg, ip). Guinea pigs included in the toxicokinetic study gained body weight, maintained a normal relative body composition, and exhibited no gross signs of toxicity during the 45-day study. Approximately 36% of the dose of TCDD-derived /sup 3/H remained in the adipose tissue at 45 days following exposure to (/sup 3/H)TCDD, while the liver, pelt, and skeletal muscle and carcass each contained about 7% of the administered dose. Although most of the TCDD-derived radioactivity in liver, kidney, perirenal adipose tissue, and skeletal muscle represented unchanged TCDD, from 4 to 28% of the /sup 3/H was associated with metabolites of TCDD. This unexpected finding suggests that TCDD metabolites are not efficiently excreted from guinea pigs. The urinary and fecal excretion of TCDD-derived radioactivity followed apparent first-order kinetics, with an elimination half-life of 93.7 +/- 15.5 days (mean +/- SD). HPLC analysis of urine and bile from (/sup 3/H)TCDD-treated guinea pigs showed that all of the radioactivity represented metabolites of TCDD, indicating that these routes of elimination are dependent on prior metabolism of TCDD. However, 70 to 90% of the radioactivity in fecal samples was found to represent unmetabolized TCDD throughout the 45-day excretion study. The presence of TCDD in feces and its absence in bile suggest that the fecal excretion of unchanged TCDD resulted from the direct intestinal elimination of the lipophilic toxin.

  12. CaO-MgO-Al2O3-SiO2 (CMAS) corrosion of Gd2Zr2O7 and Sm2Zr2O7

    DOE PAGES

    Wang, Honglong; Bakal, Ahmet; Zhang, Xingxing; Tarwater, Emily; Sheng, Zhizhi; Fergus, Jeffrey W.

    2016-08-08

    Ceramic thermal barrier coatings are applied to superalloys used in gas turbine engineering to increase the operating temperature and the energy conversion efficiency. However, dust consisting of CaO-MgO-Al2O3-SiO2 (CMAS) from the air can be injected into the engines and corrode the thermal barrier coatings. Lanthanide zirconates are promising materials in thermal barrier coatings due to their low thermal conductivities, good phase stability and good corrosion resistance. However, the corrosion resistance mechanism of CMAS on lanthanide zirconates is still not clearly understood. In this work, the corrosion mechanism of Gd2Zr2O7 and Sm2Zr2O7 in CMAS is studied. Here, the results show thatmore » the CMAS can easily react with lanthanide zirconate thermal barrier coatings to form a dense layer, which can resist further corrosion« less

  13. Identification of dipeptidyl peptidase 3 as the Angiotensin-(1-7) degrading peptidase in human HK-2 renal epithelial cells.

    PubMed

    Cruz-Diaz, Nildris; Wilson, Bryan A; Pirro, Nancy T; Brosnihan, K Bridget; Marshall, Allyson C; Chappell, Mark C

    2016-09-01

    Angiotensin-(1-7) (Ang-(1-7)) is expressed within the kidney and exhibits renoprotective actions that antagonize the inflammatory, fibrotic and pro-oxidant effects of the Ang II-AT1 receptor axis. We previously identified a peptidase activity from sheep brain, proximal tubules and human HK-2 proximal tubule cells that metabolized Ang-(1-7); thus, the present study isolated and identified the Ang-(1-7) peptidase. Utilizing ion exchange and hydrophobic interaction chromatography, a single 80kDa protein band on SDS-PAGE was purified from HK-2 cells. The 80kDa band was excised, the tryptic digest peptides analyzed by LC-MS and a protein was identified as the enzyme dipeptidyl peptidase 3 (DPP 3, EC: 3.4.14.4). A human DPP 3 antibody identified a single 80kDa band in the purified enzyme preparation identical to recombinant human DPP 3. Both the purified Ang-(1-7) peptidase and DPP 3 exhibited an identical hydrolysis profile of Ang-(1-7) and both activities were abolished by the metallopeptidase inhibitor JMV-390. DPP 3 sequentially hydrolyzed Ang-(1-7) to Ang-(3-7) and rapidly converted Ang-(3-7) to Ang-(5-7). Kinetic analysis revealed that Ang-(3-7) was hydrolyzed at a greater rate than Ang-(1-7) [17.9 vs. 5.5 nmol/min/μg protein], and the Km for Ang-(3-7) was lower than Ang-(1-7) [3 vs. 12μM]. Finally, chronic treatment of the HK-2 cells with 20nM JMV-390 reduced intracellular DPP 3 activity and tended to augment the cellular levels of Ang-(1-7). We conclude that DPP 3 may influence the cellular expression of Ang-(1-7) and potentially reflect a therapeutic target to augment the actions of the peptide. PMID:27315786

  14. Effects of Y3+/Er3+ ratio on the 2.7 μm emission of Er3+ ions in oxyfluoride glass-ceramics

    NASA Astrophysics Data System (ADS)

    Zhao, Zhiyong; Liu, Chao; Xia, Mengling; Wang, Jing; Han, Jianjun; Xie, Jun; Zhao, Xiujian

    2016-04-01

    Y3+/Er3+ ions co-doped oxyfluoride glass-ceramics were investigated to realize efficient 2.7 μm emission. Incorporation of Er3+ ions into the fluoride nanocrystals was confirmed by the X-ray diffraction patterns, absorption spectra, emission spectra and Judd-Ofelt analysis. With an increase in the Y3+/Er3+ ratio, radiative lifetime, quantum efficiency and emission cross section of the 2.7 μm emission from Er3+ ions were greatly improved, due to the reduced effective concentration of Er3+ ions and suppressed cross relaxation processes among Er3+ ions in the fluoride nanocrystals. Compared to other Er3+-doped glasses, Y3+/Er3+ co-doped oxyfluoride glass-ceramics showed a promising potential for gain medium.

  15. Stability of bulk Ba2YCu3O(7-x) in a variety of environments

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Hepp, Aloysius F.; Curtis, Henry B.; Schupp, Donald A.; Hambourger, Paul D.; Blue, James W.

    1988-01-01

    Small bars of ceramic Ba2YCu3O(7-x) were fabricated and subjected to environments similar to those that might be encountered during some NASA missions. These conditions include ambient conditions, high humidity, vacuum, and high fluences of electrons and protrons. The normal state resistivity or critical current density (J sub c) were monitored during these tests to assess the stability of the material. When normal state resistivity is used as a criterion, the ambient stability of these samples was relatively good, exhibiting only a 2 percent degradation over a 3 month period. The humidity stability was shown to be very poor, and to be a steep function of temperature. Samples stored at 50 C for 40 min increased in normal state resistivity by four orders of magnitude. Kinetic analysis indicates that the degradation reaction is second order with water vapor concentration. It is suspected that humidity degradation also accounts for the ambient instability. The samples were stable to vacuum over a period of at least 3 months. Degradation of J sub c in a 1 MeV electron fluence of 9.7 x 10 to the 14th e(-)/sq cm was determined to be no more than about 2 percent. Degradation of J sub c in a 8.7 x 10 to the 14th p(+)/sq cm of 42 MeV protons was found to be grain size dependent. Samples with smaller grain size and initial J sub c of about 240 A/sq cm showed no degradation. while that with larger grain size and an initial J sub c of about 30 A/sq cm degraded to 37 percent of its original value.

  16. Slot Antenna Coupled YBa2Cu3O7-δ Josephson Mixers for Millimeter Wave Radiation

    NASA Astrophysics Data System (ADS)

    Hasegawa, Akihisa; Uchida, Takashi; Yasuoka, Yoshizumi

    1999-12-01

    The antenna structure and the direction of the irradiated signal wave were investigated in order to improve the responsivity of a slot antenna coupled YBa2Cu3O7-δ (YBCO) Josephson mixer. The slot antenna coupled Josephson mixer consists of a thin-film slot antenna on a fused quartz substrate and a YBCO Josephson junction on a MgO substrate. It was found that maximum responsivity was obtained by letting the thickness of the MgO substrate be odd multiples of λd/4 (λd: wavelength in the substrate) and irradiating the electromagnetic wave through the MgO substrate. Furthermore, the device with the optimized structure improved the responsivity in the third-harmonic mixing by 7 dB compared to the device without a slot antenna in the harmonicmixing at 48 GHz.

  17. Characterization of YBa_2Cu_3O7 bolometric detectors for far-IR receivers

    NASA Astrophysics Data System (ADS)

    Li, C. T.; Lee, Mark

    1997-03-01

    We have measured the homodyne responsivity of a narrow-line YBa2 Cu_3O7 thin film bolometric mixer coupled to a double-slot resonant antenna at 585 GHz. These bolometers are meant for low-power, wide-bandwidth far-IR receivers. Thus far, a responsivity of 10V/W has been achieved, limited primarily by the coupling efficiency to the radiation and by internal impedance mismatches. We will discuss the noise characteristics and the IF bandwidth of such a device used as a heterodyne mixer at 90 GHz.

  18. Enhancement of transport critical current density by Gd substitution in YBa2Cu3O7

    NASA Astrophysics Data System (ADS)

    Sastry, P. V. P. S. S.; Gopalakrishnan, I. K.; Yakhmi, J. V.; Iyer, R. M.

    1988-04-01

    Samples with composition Y(1-x)Gd(x)Ba2Cu3O7 (x = 0.001-0.005) are prepared and Tc, Delta Tc, Jc and room-temperature resistivity are measured. It is shown that upon substituting yttrium by small amounts of gadolinium, Jc can be improved significantly. The anticorrelation of Jc with Delta Tc and room-temperature resistivity is established. The possible role of gadolinium in enhancing Jc is discussed. General guidelines for getting high Jc values are gathered.

  19. Metamagnetic quantum criticality in Sr3Ru2O7 studied by thermal expansion.

    PubMed

    Gegenwart, P; Weickert, F; Garst, M; Perry, R S; Maeno, Y

    2006-04-01

    We report low-temperature thermal expansion measurements on the bilayer ruthenate Sr3Ru2O7 as a function of magnetic field applied perpendicular to the ruthenium-oxide planes. The field dependence of the c-axis expansion coefficient indicates the accumulation of entropy close to 8 T, related to an underlying quantum critical point. The latter is masked by two first-order metamagnetic transitions which bound a regime of enhanced entropy. Outside this region the singular thermal expansion behavior is compatible with the predictions of the itinerant theory for a two-dimensional metamagnetic quantum critical end point. PMID:16712009

  20. Anisotropy of I- V characteristics in YBa 2Cu 3O 7- δ films

    NASA Astrophysics Data System (ADS)

    Nojima, T.; Iimura, H.; Kuwasawa, Y.; Nakano, S.; Yamaguchi, T.

    1994-12-01

    Current voltage ( itI- V) curves CVD-YBa 2Cu 3O 7- δ films near the glass transition temperature Tg in the mixed state are studied as a function of the angle θ between magnetic field and c axis. In the vortex-glass scaling analysis of I- V curves, it is found that the glass critical exponentsare independent of θ, and do not show a remarkable change even at θ=90°( H⊥ c). Our results indicates that periodic plane-like intrinsic pinning is not so effective near Tg and vortices are pinned at the random point-like disorder for all field directions.

  1. Visible-light driven Gd2Ti2O7/GdCrO3 composite for hydrogen evolution.

    PubMed

    Parida, K M; Nashim, Amtul; Mahanta, Saroj Ku

    2011-12-28

    A series of Gd(2)Ti(2)O(7)/GdCrO(3) composites are prepared by solid state combustion method using Gd(NO(3))(3), TiO(2), Cr(2)O(3) as metal source and urea as a fuel. The composites are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible diffuse reflectance spectra (DRUV-vis), Brunauer-Emmett-Teller (BET) surface area measurements, photoluminescence spectra (PL), X-ray photoelectron spectroscopic (XPS) studies, photocurrent measurements etc. The photocatalytic activity of the composites is examined towards hydrogen production without using any co-catalyst under visible light illumination. The rate of formation of hydrogen is measured by the photocatalytic activity measurement device and gas chromatography (GC). The highest efficiency is observed over the composite GTC (Cr:Gd:Ti = 1:1:1). On the basis of photocurrent measurements and PL, a mechanism for the enhanced photocatalytic activity has been discussed.

  2. Teratogenicity of 2,3,7,8-tetrachlorodibenzofuran in the mouse

    SciTech Connect

    Hassoun, E.; d'Argy, R.; Dencker, L.

    1984-01-01

    2,3,7,8-Tetrachlorodibenzofuran (TCDBF) was administered in single doses (0.1-0.8 mg/kg body weight) intraperitoneally to pregnant C57BL mice on d 10, 11, 12, or 13 of gestation. A dose-dependent increase was observed in the frequency of fetal resorptions and fetal death, especially in the earlier stages (d 10-11). Cleft palate and hydronephrosis as well appeared in a dose-dependent manner, with a peak in sensitivity after administration on d 11-12. TCDBF given at a dose level of 0.1 mg/kg body weight on d 12 of gestation (only dose- and stage-tested) produced a marked thymic hypoplasia as well. A few cases of general hydrops occurred. The pattern of malformations and time of sensitivity corresponded well to that observed earlier after administration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; ED50 approx. = 25 ..mu..g/kg) and 3,3',4,4'-tetrachloroazoxybenzene (TCAOB; ED50 approx. = 6 mg/kg), two congeners of TCDBF, indicating common mechanisms of action of this family of compounds. Ornithine decarboxylase (ODC) is an important enzyme in cell proliferation and growth with a high activity in embryonic tissues. Liver ODC activity has previously been found to be stimulated by TCDD in weanling mice. However, this enzyme was not found to be stimulated in fetal and placental tissues, but slightly in maternal kidney after treatment with TCDBF in teratogenic doses. It is possible that the ODC activity increases under certain conditions only, on administration of TCDD and its congeners. 40 references, 3 tables, 3 figures.

  3. Temperature dependence of far-infrared difference reflectivity of YBa2Cu3O7-y

    NASA Astrophysics Data System (ADS)

    Krenn, H.; Bauer, G.; Vogl, G.; Strasser, G.; Gornik, E.

    1989-04-01

    Far-infrared difference reflectivity spectra (50-450 cm-1) below, across and above the transition temperature on polycrystalline single-phase YBa2Cu3O7-y samples were measured. The data are compared with model fits using the explicit temperature dependence of the Mattis-Bardeen conductivity, an effective-medium approach and temperature-dependent phonon oscillator parameters and alternatively a plasma model. For the plasma model we alternatively use a generalized Drude-like expression with a frequency-dependent damping after Thomas et al. [Phys. Rev. B 36, 846 (1987)] or the original model with Orenstein et al. [Phys. Rev. B 36, 729 (1987)] and Sherwin, Richards, and Zettl [Phys. Rev. B 37, 1587 (1988)] with a Drude contribution plus a mid-infrared oscillator, but with constant carrier relaxation rates. The models explain the difference reflectivity data (precision <0.2%) with a fitting accuracy of 1-2 % (Mattis-Bardeen model) or 2-3 % (plasma model) over the full temperature range. In order to investigate their applicability, reflectivity, and conductivity data of a highly oriented YBa2Cu3O7-y sample, as recently published by Bonn et al. [Phys. Rev. Lett. 58, 2249 (1987)], were also fitted with both models. Because of the frequency dependence of the free-carrier damping rates, it was important to fulfill the Kramers-Kronig relations between the real and the imaginary part of the dynamic conductivity in the calculations. For both models the characteristic dependences of the conductivity on frequency and temperature are given. Whereas, naturally, the Mattis-Bardeen model yields a gaplike depression of the conductivity for frequencies below an assumed gap, the plasma model results in somewhat smoother dependences of Re(σ(ω)) and Im(σ(ω)) in the frequency region of interest.

  4. Momentum density and 2D-ACAR experiments in YBa sub 2 Cu sub 3 O sub 7

    SciTech Connect

    Bansil, A. . Dept. of Physics); Smedskjaer, L.C. )

    1991-12-01

    We compare measured c-projected 2D-ACAR spectrum from an untwinned single crystal of YBa{sub 2}Cu{sub 3}O{sub 7-x} with the corresponding band theory predictions. Many different one-dimensional sections through the spectrum are considered, together with the characteristic amplitudes and shapes of the spectral anisotropies, with a focus on identifying and delineating Fermi surface signatures in the spectra. The positron data clearly show several distinct features of the ridge Fermi surface predicted by the band theory, and give an indication of the pillbox Fermi sheet. The good agreement between theory and experiment suggests that the band theory framework based on the local density approximation (LDA) is capable of providing a substantially correct description of the momentum density and Fermiology of the normal ground state electronic structure of YBa{sub 2}Cu{sub 3}O{sub 7}.

  5. Disorder-controlled superconductivity at YBa2Cu3O7/SrTiO3 interfaces

    NASA Astrophysics Data System (ADS)

    Garcia-Barriocanal, J.; Perez-Muñoz, A. M.; Sefrioui, Z.; Arias, D.; Varela, M.; Leon, C.; Pennycook, S. J.; Santamaria, J.

    2013-06-01

    We examine the effect of interface disorder in suppressing superconductivity in coherently grown ultrathin YBa2Cu3O7 (YBCO) layers on SrTiO3 (STO) in YBCO/STO superlattices. The termination plane of the STO is TiO2 and the CuO chains are missing at the interface. Disorder (steps) at the STO interface cause alterations of the stacking sequence of the intracell YBCO atomic layers. Stacking faults give rise to antiphase boundaries which break the continuity of the CuO2 planes and depress superconductivity. We show that superconductivity is directly controlled by interface disorder outlining the importance of pair breaking and localization by disorder in ultrathin layers.

  6. [{sup 3}H]-2,3,7,8-TCDD uptake and elimination kinetics of medaka (Oryzias latipes)

    SciTech Connect

    Schmieder, P.; Lothenbach, D.; Tietge, J.; Erickson, R.; Johnson, R.

    1995-10-01

    Uptake and elimination rate constants for [{sup 3}H]-2,3,7,8-tetrachlorodibenzo-p-dioxin ([{sup 3}H]TCDD) were estimated by exposing medaka (Oryzias latipes) to [{sup 3}H]TCDD in flowing water with no solvent carriers. Uptake was determined from body-burdens measured on exposure days 0, 2, 4, 6, 10, and 12. Elimination was quantified for whole fish after 28, 90, and 175 d in uncontaminated water. Medaka accumulated [{sup 3}H]TCDD at a rapid rate, achieving residues 24,000 times the water concentration after 12 d, with no indication of approach to steady state. After 6 months in uncontaminated water, the pg TCDD/g decreased by 69%, much of the decrease due to growth dilution as evidenced by only a 47% decrease in the pg TCDD/fish. Uptake and elimination rate constant (2,300 ml/g/d and 0.0045/d, respectively) were estimated by fitting a one-compartment, linear, mass-balance model to the data, adjusting for growth rate. The experimental design, including solvent-free delivery of [{sup 3}H]TCDD, exposure at concentrations below maximum water solubility, and measurement of fish growth and lipid content during a 6-month elimination phase, resulted in a predicted steady-state bioconcentration factor (BCF) for medaka of 510,000, a number considerably higher than previously reported for dioxin BCFs. Kinetic parameters were used to successfully predict TCDD BCF in medaka exposed independently.

  7. Immunomodulatory Response Triggered by the Alkaloids, 3-Amino-7-Benzylbenzimidazo[3,2-a] Quinolinium Chloride (ABQ-48) and 3-Nitro-7-Benzylbenzimidazo [3,2-a] Quinolinium Chloride (NBQ-48)

    PubMed Central

    Otero, Miguel; Zayas, Beatriz; Miranda, Eric; Velez, Christian; Hernandez, Wigberto J.; Rivera, Luis A.; Cox, Osvaldo

    2015-01-01

    ABQ-48 (3-amino-7-benzylbenzimidazo[3,2-a]quinolinium chloride) and NBQ-48 (3-nitro-7-benzylbenzimidaw[3,2-a] quinolinium chloride) are un-natural alkaloids containing a planar heteroaromatic systems characterized by quaternized nitrogen fused to benzothiazole nucleus. Both compounds are structurally related to naturally occurring substances such as elliptine (from Ochrosia), and berberine (from Berberis). Previous in vitro studies have shown these agents to control tumor-cell proliferation indicating that both BQS are active but especially ABQ-48 at a 1 OuM dose with over 80% control of the proliferation of multiple cancer cell lines from various etiologies including colon, melanoma, CNS and ovarian cells. Mechanism of action studies have also been conducted however this is the first approach to evaluate immune modulatory activity of these novel BQS. Immune-based therapy is an increasing field in which scientists identify how the immunomodulatory activity of known and newly discovered compounds elicits an immune response that could be used against diseases. In this study, our main objective was to apply an in vitro model to show the immunomodulatory effects of ABQ-48 and NBQ-48 by analyzing the cytokine profile resulting after extracted murine spleen cells were treated with both BQS using a fluorescence-based multiplex ELISA approach. Screened cytokines included: G-CSF, GM-CSF, IL-1a, IL-2, IL-3, IL-5, IL-6, IL-7, IL-10, IL-12p70, IL-13, IL-15, IL-17, IL-21, IL-23, IFN-γ, and TNF-α. Our study results show ABQ 48 and NBQ-48 to stimulate the release of G-CSF, IL-2, IL-6, and, IFN-γ when mouse splenocytes are incubated with serial dilutions of these agents. Our finding opens new possibilities of potentially using ABQ-48 and NBQ-48 as immunomodulatory agents; with intend to activate the immune system such as the production of neutrophils against cancer or reducing chemotherapy side effects. PMID:26086027

  8. All-YBa2Cu3O(7-x) edge-geometry weak links

    NASA Technical Reports Server (NTRS)

    Hunt, B. D.; Bajuk, L. J.; Barner, J. B.; Foote, M. C.; Jones, B. B.; Vasquez, R. P.

    1992-01-01

    High quality YBa2Cu3O(7-x)/normal-metal/YBa2Cu3O(7-x) edge-geometry weak links are fabricated using nonsuperconducting Y-Ba-Cu-O barrier layers deposited by laser ablation at reduced growth temperatures. Devices incorporating 25-100-A-thick barrier layers exhibit current-voltage characteristics consistent with the resistively-shunted-junction model, as well as ac Josephson steps. Magnetic field modulation of the critical currents shows Fraunhofer-like behavior with a periodicity which scales with device area. The critical currents vary exponentially with barrier thickness indicating an effective normal metal coherence length of 20 A. The average resistances scale linearly with Y-Ba-Cu-O interlayer thickness and device area. The scaling behavior of the device parameters combined with the well-behaved magnetic field modulation of the critical currents demonstrates good barrier-layer uniformity with low pinhole densities. Near the transition temperature, the critical currents exhibit a temperature dependence proportional to (1 - T/Tc) squared.

  9. Cleaning of YBa2Cu3O7-x surfaces by thermal oxidation treatments

    NASA Astrophysics Data System (ADS)

    Sobolewski, M. A.; Semancik, S.; Kreider, K.

    1990-01-01

    When exposed to air, YBa2Cu3O7-x reacts to form a nonsuperconducting surface layer which degrades the quality of devices formed by subsequent deposition of overlayers. Degradation may also be caused by contamination of the surface during prior processing. We have investigated the use of thermal oxidation treatments as a means of restoring these surfaces, in situ, prior to overlayer deposition. The oxidations were performed in a dual chamber UHV system equipped with x-ray and ultraviolet photoelectron spectroscopies, ion scattering spectroscopy, and a four point probe for in situ resistance measurements. Sputter-deposited, annealed YBa2Cu3O7-x thin films exposed to air underwent treatments at 350-650 °C for 5-60 min in 10-300 Torr of oxygen. Carbonate contamination was removed at T≥460 °C. Chlorine contamination present on some samples was removed at T≥600 °C. Resistance measurements indicate that the oxygen content within the films can be maintained during these treatments if a suitable temperature profile is used. The resulting surfaces are not ideal—an insulating layer ˜1 nm thick and deficient in yttrium is present. Nevertheless, the treatments described here may prove to be useful steps in device fabrication.

  10. Antiferromagnetic instability in Sr3Ru2O7: stabilized and revealed by dilute Mn impurities

    NASA Astrophysics Data System (ADS)

    Hossain, Muhammed; Bohnenbuck, B.; Chuang, Y.-D.; Cruz, E.; Wu, H.-H.; Tjeng, L. H.; Elfimov, I. S.; Hussain, Z.; Keimer, B.; Sawatzky, G. A.; Damascelli, A.

    2009-03-01

    X-ray Absorption Spectroscopy (XAS) and Resonant Elastic Soft X-ray Scattering (RESXS) studies have been performed on Mn-doped Sr3Ru2O7, both on the Ru and Mn L-edges, to investigate the origin of the metal insulator transition. Extensive simulations based on our experimental findings point toward an intrinsic antiferromagnetic instability in the parent Sr3Ru2O7 compound that is stabilized by the dilute Mn impurities. We show that the metal-insulator transition is a direct consequence of the antiferromagnetic order and we propose a phenomenological model that may be applicable also to metal-insulator transitions seen in other oxides. Moreover, a comparison of Ru and Mn L-edge data on 5% Mn doped system reveals that dilute Mn impurities are generating much more intense signal than Ru which is occupying 95% of the lattice sites. This suggests the embedding of dilute impurities as a powerful mean to probe weak and, possibly, spatially inhomogeneous order in solid-state systems. In collaboration with: Y. Yoshida (AIST), J. Geck, D.G. Hawthorn (UBC), M.W. Haverkort, Z. Hu, C. Sch"ußler-Langeheine (Cologne), R. Mathieu, Y. Tokura, S. Satow, H. Takagi (Tokyo), J.D. Denlinger (ALS).

  11. Fluctuation conductivity of oxygen underdoped YBa2Cu3O7-δ single crystals

    NASA Astrophysics Data System (ADS)

    Vovk, R. V.; Khadzhai, G. Ya.; Goulatis, I. L.; Chroneos, A.

    2014-03-01

    The electrical resistance in the range of ТC-300 K in the layer planes of YВа2Сu3О7-δ single crystals with a range of oxygen deficiency (providing a range of TC from 78 to 92 K) was investigated. The experimental data is approximated by an expression that accounts for the scattering of electrons on phonons, as well as on defects and the fluctuation conductivity in a 3-D model of the Aslamazov-Larkin theory. According to this approximation, depending upon the oxygen deficiency, the Debye temperature varies from 245 to 400 K, coherence length ξС(0)≈0.5 Å.

  12. DETECTION OF EXTENDED VHE GAMMA RAY EMISSION FROM G106.3+2.7 WITH VERITAS

    SciTech Connect

    Acciari, V. A.; Benbow, W.; Aliu, E.; Boltuch, D.; Arlen, T.; Chow, Y. C.; Aune, T.; Bautista, M.; Cogan, P.; Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R.; Bradbury, S. M.; Butt, Y.; Byrum, K.; Cannon, A.; Cesarini, A.; Ciupik, L.; Cui, W. E-mail: wakely@uchicago.ed

    2009-09-20

    We report the detection of very-high-energy (VHE) gamma-ray emission from supernova remnant (SNR) G106.3+2.7. Observations performed in 2008 with the VERITAS atmospheric Cherenkov gamma-ray telescope resolve extended emission overlapping the elongated radio SNR. The 7.3sigma (pre-trials) detection has a full angular extent of roughly 0.{sup 0}6 by 0.{sup 0}4. Most notably, the centroid of the VHE emission is centered near the peak of the coincident {sup 12}CO (J = 1-0) emission, 0.{sup 0}4 away from the pulsar PSR J2229+6114, situated at the northern end of the SNR. Evidently the current-epoch particles from the pulsar wind nebula are not participating in the gamma-ray production. The VHE energy spectrum measured with VERITAS is well characterized by a power law dN/dE = N {sub 0}(E/3 TeV){sup -G}AMMA with a differential index of GAMMA = 2.29 +- 0.33{sub stat} +- 0.30{sub sys} and a flux of N{sub 0} = (1.15 +- 0.27{sub stat} +- 0.35{sub sys}) x 10{sup -13} cm{sup -2} s{sup -1} TeV{sup -1}. The integral flux above 1 TeV corresponds to {approx}5 percent of the steady Crab Nebula emission above the same energy. We describe the observations and analysis of the object and briefly discuss the implications of the detection in a multiwavelength context.

  13. Influence of La2Zr2O7 Additive on Densification and Li+ Conductivity for Ta-Doped Li7La3Zr2O12 Garnet

    NASA Astrophysics Data System (ADS)

    Huang, Xiao; Shen, Chen; Rui, Kun; Jin, Jun; Wu, Meifen; Wu, Xiangwei; Wen, Zhaoyin

    2016-10-01

    A high-conductivity solid electrolyte, La2Zr2O7 (LZO) added to Li6.4La3Zr1.4Ta0.6O12 (LLZTO), was prepared via conventional solid-state reactions and sintered at 1100°C for 10 h, which is tens of Celsius degrees lower than the typical sintering temperature for LLZTO. The addition of LZO did not bring in any impurities. LZO acted as a sintering aid to densify the LLZTO from a relative density of 77% up to 90%, which was comparable to that of pure LLZTO sintered at 1200°C. The 6 wt.% LZO-LLZTO samples sintered at 1100°C and 1200°C exhibited a room-temperature conductivity of 1.92 × 10-4 S/cm and 5.84 × 10-4 S/cm, respectively, which were higher than that of pure LLZTO samples. Glass-like phases observed at grain boundaries in LZO-LLZTO ceramics indicated that LZO promoted the formation of the glass-like phases binding together LLZTO grains and thus leading to enhanced density and conductivity of LLZTO.

  14. Influence of La2Zr2O7 Additive on Densification and Li+ Conductivity for Ta-Doped Li7La3Zr2O12 Garnet

    NASA Astrophysics Data System (ADS)

    Huang, Xiao; Shen, Chen; Rui, Kun; Jin, Jun; Wu, Meifen; Wu, Xiangwei; Wen, Zhaoyin

    2016-08-01

    A high-conductivity solid electrolyte, La2Zr2O7 (LZO) added to Li6.4La3Zr1.4Ta0.6O12 (LLZTO), was prepared via conventional solid-state reactions and sintered at 1100°C for 10 h, which is tens of Celsius degrees lower than the typical sintering temperature for LLZTO. The addition of LZO did not bring in any impurities. LZO acted as a sintering aid to densify the LLZTO from a relative density of 77% up to 90%, which was comparable to that of pure LLZTO sintered at 1200°C. The 6 wt.% LZO-LLZTO samples sintered at 1100°C and 1200°C exhibited a room-temperature conductivity of 1.92 × 10-4 S/cm and 5.84 × 10-4 S/cm, respectively, which were higher than that of pure LLZTO samples. Glass-like phases observed at grain boundaries in LZO-LLZTO ceramics indicated that LZO promoted the formation of the glass-like phases binding together LLZTO grains and thus leading to enhanced density and conductivity of LLZTO.

  15. Ferroelectric properties of (Ba,Sr)TiO3 thin films grown on YBa2Cu3O7 layers

    NASA Astrophysics Data System (ADS)

    Tao, K.; Hao, Z.; Xu, B.; Chen, B.; Miao, J.; Yang, H.; Zhao, B. R.

    2003-09-01

    Ferroelectric and superconductor bilayers of Ba1-xSrxTiO3(BST)/YBa2Cu3 O7 (YBCO) are grown on (001) SrTiO3 substrates by magnetron sputtering and pulsed laser deposition. The BST thin films exhibit typical ferroelectric behavior in their hysteresis loops. Capacitance-voltage curves are measured. From the capacitance, a dielectric constant of 1250 is obtained. The current-voltage curve is fitted to investigate the mechanism of leakage. The Schottky barrier height at the Ag/BST interface is calculated to be 0.521 eV. The trapped level Et in BST is estimated to be 0.335 eV below the conduction-band edge. An energy band diagram of the Ag/BST/YBCO structure is proposed to explain the experimental results.

  16. 2,3,7, 8-TETRACHLORODIBENZO-P-DIOXIN (TCDD)-MEDIATED OXIDATIVE STRESS IN FEMALE CYP1A-2 KNOCKOUT (CYP1A2-/-) MICE

    EPA Science Inventory

    2,3,7,8-Tetrachlordibenzo-p-dioxin (TCDD)-Mediated Oxidative Stress in Female CYP1A2 Knockout (CYP1A2-/-) Mice

    Deborah Burgin1, Janet Diliberto2, Linda Birnbaum2
    1UNC Toxicology; 2USEPA/ORD/NHEERL, RTP, NC

    Most of the effects due to TCDD exposure are mediated via...

  17. Fermi Surface and Van Hove Singularities in the Itinerant Metamagnet Sr(3)Ru(2)O(7)

    SciTech Connect

    Tamai, A.; Allan, M.P.; Mercure, J.F.; Meevasana, W.; Dunkel, R.; Lu, D.H.; Perry, R.S.; Mackenzie, A.P.; Singh, D.J.; Shen, Z.-X.; Baumberger, F.; /Scottish U. Research Reactor Ctr. /St. Andrews U.

    2011-01-04

    The low-energy electronic structure of the itinerant metamagnet Sr{sub 3}Ru{sub 2}O{sub 7} is investigated by angle resolved photoemission and density functional calculations. We find well-defined quasiparticle bands with resolution limited line widths and Fermi velocities up to an order of magnitude lower than in single layer Sr{sub 2}RuO{sub 4}. The complete topography, the cyclotron masses and the orbital character of the Fermi surface are determined, in agreement with bulk sensitive de Haas - van Alphen measurements. An analysis of the dxy band dispersion reveals a complex density of states with van Hove singularities (vHs) near the Fermi level; a situation which is favorable for magnetic instabilities.

  18. Immunological markers among workers exposed to 2,3,7,8- tetrachlorodibenzo-p-dioxin

    PubMed Central

    Halperin, W.; Vogt, R.; Sweeney, M. H.; Shopp, G.; Fingerhut, M.; Petersen, M.

    1998-01-01

    OBJECTIVES: To examine the association of immune cell number and function with occupational exposure to substances contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). METHODS: A cross sectional medical survey. The exposed participants were employed at two chemical plants between 1951 and 1972 in the manufacture of 2,4,5- trichlorophenate and its derivatives. The reference group consisted of people with no occupational exposure to phenoxy herbicides who lived within the communities of the workers. Data from a total of 259 workers and 243 unexposed referents were included in the analysis of immune function. Laboratory tests for immune status included enumeration of circulating leukocyte and lymphocyte populations, proliferative responses of circulating lymphocytes to mitogens and antigens, and serum concentrations of the major immunoglobulins and complement factor C3. RESULTS: The workers had substantial exposure to substances contaminated with TCDD, as indicated by a lipid adjusted mean serum TCDD concentration of 229 ppt compared with a mean of 6 ppt in the unexposed referents. Workers were divided into categories based on their serum TCDD concentration. For all categories except the lowest, with values of serum TCDD comparable with the unexposed referents, there were increased odds of having lower counts of CD26 cells (activated T cells) (odds ratio (OR) 1.0, 95% confidence interval (95% CI) 0.5 to 1.8 for TCDD < 20 ppt; OR 1.6, 95% CI 0.8 to 3.2 for TCDD 20- 51 ppt; OR 2.7, 95% CI 1.4 to 5.1 for TCDD 52-125 ppt; OR 2.6, 95% CI 1.4 to 4.9 for TCDD 125-297 ppt; OR 2.4, 95% CI 1.3 to 4.6 for TCDD 298- 3389 ppt). A less consistent finding was decreased spontaneous proliferation of cultured lymphocytes. However, increases were found in proliferation of lymphocytes in response to concanavalin and pokeweed in workers in the high TCDD category. Age, cigarette smoking, and alcohol were significant predictors of several immunological outcomes. CONCLUSIONS

  19. Optical resolution by preferential crystallization of (1RS,3RS)-1,2,3,4-tetrahydro-6,7-dihydroxy-1-methyl-3-isoquinolinecarboxylic acid.

    PubMed

    Shiraiwa, Tadashi; Kiyoe, Ryuuichi

    2005-09-01

    The racemic structure of (1RS,3RS)-1,2,3,4-tetrahydro-6,7-dihydroxy-1-methyl-3-isoquinolinecarboxylic acid [(1RS,3RS)-1] was examined based on the melting point, solubility, and IR spectrum, with the aim of optical resolution by preferential crystallization. (1RS,3RS)-1 was indicated from these results to exist as a conglomerate. The successive optical resolution by preferential crystallization of (1RS,3RS)-1 yielded (1S,3S)- and (1R,3R)-1 with optical purities of 85--95% at 66--81% degrees of resolution, which were fully purified by recrystallization.

  20. Flux compression measurements in sintered bulk Ba2YCu3O7

    NASA Technical Reports Server (NTRS)

    Israelsson, U. E.; Strayer, D. M.

    1991-01-01

    Trapping of magnetic fields and subsequent flux compression have been realized in sintered bulk Ba2YCu3O7 superconductors at 77 K. The field is trapped in two interconnected holes of 0.95-cm and 0.52-cm diameter, respectively. By inserting a superconducting plunger with a diameter of 0.93 cm into the larger hole, the trapped flux is compressed into the smaller hole, where the flux density is measured with a Hall probe. The ratio of the areas available for the magnetic flux before and after compression is 3.7. Deviations from this compression ratio are observed to increase as the trapped field is increased, demonstrating penetration of magnetic flux into the interior of the superconductor. Using a simple extension of the critical state model, the authors demonstrate how the flux compression technique can be used to test the validity of the model and also to calculate the critical current density of the superconductor directly from the measurements.

  1. X-ray studies of 2-amino-4-(3-nitrophenyl)-5-oxo-4,5-dihydropyrano[3,2- c] chromene-3-carbonitrile and 2-amino-7,7-dimethyl-4-(4-nitrophenyl)-5-oxo-5,6,7,8-tetrahydro-4 H-chromene-3-carbonitrile

    NASA Astrophysics Data System (ADS)

    Sharma, S.; Banerjee, B.; Brahmachari, G.; Kant, R.; Gupta, V. K.

    2015-12-01

    Two carbonitrile compounds, 2-amino-4-(3-nitrophenyl)-5-oxo-4,5-dihydropyrano[3,2- c] chromene-3-carbonitrile ( I) and 2-amino-7,7-dimethyl-4-(4-nitrophenyl)-5-oxo-5,6,7,8-tetrahydro-4 H-chromene-3-carbonitrile ( II), were synthesized, and their crystal structures were determined by X-ray diffraction technique. The crystals are triclinic, a = 7.7970(12), 8.2171(7), b = 9.0390(10), 9.2238(7), c = 15.148(2), 14.5585(11) Å, α = 81.439(10)°, 74.895(6)°, β = 75.194(12)°, 87.392(6)°, γ = 76.151(11)°, 78.552(7)°, for I and II, respectively, Z = 2, sp. gr. P overline 1. The pyran ring in both the compounds deviates significantly from planarity and adopts boat conformation. The crystal structure is stabilized by N-H···O and N-H···N hydrogen bonds.

  2. Fragrance material review on 1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-naphthalenyl)ethanone (OTNE).

    PubMed

    Scognamiglio, J; Letizia, C S; Politano, V T; Api, A M

    2013-12-01

    A toxicologic and dermatologic review of 1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-naphthalenyl)ethanone (OTNE) when used as a fragrance ingredient is presented. OTNE is a member of the fragrance structural group Alkyl Cyclic Ketones. These fragrances can be described as being composed of an alkyl, R1, and various substituted and bicyclic saturated or unsaturated cyclic hydrocarbons, R2, in which one of the rings may include up to 12 carbons. Alternatively, R2 may be a carbon bridge of C2-C4 carbon chain length between the ketone and cyclic hydrocarbon. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for OTNE were evaluated then summarized and includes physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, phototoxicity, photoallergy, toxicokinetics, repeated dose, reproductive toxicity, and genotoxicity data. A safety assessment of the entire Alkyl Cyclic Ketones will be published simultaneously with this document; please refer to Belsito et al. (2013) for an overall assessment of the safe use of this material and all Alkyl Cyclic Ketones in fragrances.

  3. Overview of the 2nd Gen 3.7m HIAD Static Load Test

    NASA Technical Reports Server (NTRS)

    Swanson, G. T.; Kazemba, C. D.; Johnson, R. K.; Hughes, S. J.; Calomino, A. M.; Cheatwood, F. M.; Cassell, A. M.; Anderson, P.; Lowery, A.

    2015-01-01

    To support NASAs long term goal of landing humans on Mars, technologies which enable the landing of heavy payloads are being developed. Current entry, decent, and landing technologies are not practical for human class payloads due to geometric constraints dictated by current launch vehicle fairing limitations. Therefore, past and present technologies are now being explored to provide a mass and volume efficient solution to atmospheric entry, including Hypersonic Inflatable Aerodynamic Decelerators (HIADs). In October of 2014, a 3.7m HIAD inflatable structure with an integrated flexible thermal protection sys-tem (F-TPS) was subjected to a static load test series to verify the designs structural performance. The 3.7m HIAD structure was constructed in a 70 deg sphere-cone stacked-toroid configuration using eight inflatable tori, which were joined together using adhesives and high strength textile webbing to help distribute the loads throughout the inflatable structure. The inflatable structure was fabricated using 2nd generation structural materials that permit an increase in use temperature to 400 C+ as compared to the 250 C limitation of the 1st generation materials. In addition to the temperature benefit, these materials also offer a 40 reduction in structure mass. The 3.7m F-TPS was fabricated using high performance materials to protect the inflatable structure from heat loads that would be seen during atmospheric entry. The F-TPS was constructed of 2nd generation TPS materials increasing its heating capability from 35W sq cm to over 100W sq cm. This test article is the first stacked-torus HIAD to be fabricated and tested with a 70 deg sphere-cone. All previous stacked-torus HIADs have employed a 60o sphere-cone. To perform the static load test series, a custom test fixture was constructed. The fixture consisted of a structural tub rim with enough height to allow for dis-placement of the inflatable structure as loads were applied. The tub rim was attached to the

  4. Li7La3Zr2O12 Interface Modification for Li Dendrite Prevention.

    PubMed

    Tsai, Chih-Long; Roddatis, Vladimir; Chandran, C Vinod; Ma, Qianli; Uhlenbruck, Sven; Bram, Martin; Heitjans, Paul; Guillon, Olivier

    2016-04-27

    Al-contaminated Ta-substituted Li7La3Zr2O12 (LLZ:Ta), synthesized via solid-state reaction, and Al-free Ta-substituted Li7La3Zr2O12, fabricated by hot-press sintering (HP-LLZ:Ta), have relative densities of 92.7% and 99.0%, respectively. Impedance spectra show the total conductivity of LLZ:Ta to be 0.71 mS cm(-1) at 30 °C and that of HP-LLZ:Ta to be 1.18 mS cm(-1). The lower total conductivity for LLZ:Ta than HP-LLZ:Ta was attributed to the higher grain boundary resistance and lower relative density of LLZ:Ta, as confirmed by their microstructures. Constant direct current measurements of HP-LLZ:Ta with a current density of 0.5 mA cm(-2) suggest that the short circuit formation was neither due to the low relative density of the samples nor the reduction of Li-Al glassy phase at grain boundaries. TEM, EELS, and MAS NMR were used to prove that the short circuit was from Li dendrite formation inside HP-LLZ:Ta, which took place along the grain boundaries. The Li dendrite formation was found to be mostly due to the inhomogeneous contact between LLZ solid electrolyte and Li electrodes. By flatting the surface of the LLZ:Ta pellets and using thin layers of Au buffer to improve the contact between LLZ:Ta and Li electrodes, the interface resistance could be dramatically reduced, which results in short-circuit-free cells when running a current density of 0.5 mA cm(-2) through the pellets. Temperature-dependent stepped current density galvanostatic cyclings were also carried out to determine the critical current densities for the short circuit formation. The short circuit that still occurred at higher current density is due to the inhomogeneous dissolution and deposition of metallic Li at the interfaces of Li electrodes and LLZ solid electrolyte when cycling the cell at large current densities.

  5. Space Weather Observations by GNSS Radio Occultation: From FORMOSAT-3/COSMIC to FORMOSAT-7/COSMIC-2

    PubMed Central

    Yue, Xinan; Schreiner, William S; Pedatella, Nicholas; Anthes, Richard A; Mannucci, Anthony J; Straus, Paul R; Liu, Jann-Yenq

    2014-01-01

    The joint Taiwan-United States FORMOSAT-3/COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) mission, hereafter called COSMIC, is the first satellite constellation dedicated to remotely sense Earth's atmosphere and ionosphere using a technique called Global Positioning System (GPS) radio occultation (RO). The occultations yield abundant information about neutral atmospheric temperature and moisture as well as space weather estimates of slant total electron content, electron density profiles, and an amplitude scintillation index, S4. With the success of COSMIC, the United States and Taiwan are moving forward with a follow-on RO mission named FORMOSAT-7/COSMIC-2 (COSMIC-2), which will ultimately place 12 satellites in orbit with two launches in 2016 and 2019. COSMIC-2 satellites will carry an advanced Global Navigation Satellite System (GNSS) RO receiver that will track both GPS and Russian Global Navigation Satellite System signals, with capability for eventually tracking other GNSS signals from the Chinese BeiDou and European Galileo system, as well as secondary space weather payloads to measure low-latitude plasma drifts and scintillation at multiple frequencies. COSMIC-2 will provide 4–6 times (10–15X in the low latitudes) the number of atmospheric and ionospheric observations that were tracked with COSMIC and will also improve the quality of the observations. In this article we focus on COSMIC/COSMIC-2 measurements of key ionospheric parameters. PMID:26213514

  6. Vortex trapping and expulsion in thin-film YBa2Cu3O7-δ strips

    NASA Astrophysics Data System (ADS)

    Kuit, K. H.; Kirtley, J. R.; van der Veur, W.; Molenaar, C. G.; Roesthuis, F. J. G.; Troeman, A. G. P.; Clem, J. R.; Hilgenkamp, H.; Rogalla, H.; Flokstra, J.

    2008-04-01

    A scanning superconducting quantum interference device microscope was used to image vortex trapping as a function of the magnetic induction during cooling in thin-film YBa2Cu3O7-δ (YBCO) strips for strip widths W from 2 to 50μm . We found that vortices were excluded from the strips when the induction Ba was below a critical induction Bc . We present a simple model for the vortex exclusion process which takes into account the vortex-antivortex pair production energy as well as the vortex Meissner and self-energies. This model predicts that the real density n of trapped vortices is given by n=(Ba-BK)/Φ0 with BK=1.65Φ0/W2 and Φ0=h/2e the superconducting flux quantum. This prediction is in good agreement with our experiments on YBCO, as well as with previous experiments on thin-film strips of niobium. We also report on the positions of the trapped vortices. We found that at low densities the vortices were trapped in a single row near the centers of the strips, with the relative intervortex spacing distribution width decreasing as the vortex density increased, a sign of longitudinal ordering. The critical induction for two rows forming in the 35μm wide strip was (2.89+1.91-0.93)Bc , consistent with a numerical prediction.

  7. Production and dechlorination of 2,3,7,8-tetrachlorodibenzo-p-dioxin in historically-contaminated estuarine sediments

    SciTech Connect

    Albrecht, I.D.; Barkovskii, A.L.; Adriaens, P.

    1999-03-01

    Polychlorinated dibenzo-p-dioxins (PCDD) are ubiquitous and considered to be unreactive to biotic and abiotic transformation processes. Here the authors demonstrate that sediment-associated 2,3,7,8-substituted dioxin residues in general, and 2,3,7,8-TCDD in particular, are in a state of flux, as they are produced from peri-dechlorination of octaCDD, and further laterally dechlorinated in 2-MCDD. This reaction can be stimulated in the presence of organic acids, 2-monobromodibenzo-p-dioxin (2-MBDD) and hydrogen, which result in the production of HpCDD, 2,3,7,8-TCDD, and 2-MCDD, respectively. The results indicate that dechlorination of 2,3,7,8-TCDD is not likely a rate-limiting step in the hydrogen-stimulated reaction, which presents a potential strategy to decontaminate dioxin-contaminated environments.

  8. Proposed occupational exposure limit for 2,3,7,8-tetrachlorodibenzo-p-dioxin

    SciTech Connect

    Leung, H.W.; Murray, F.J.; Paustenbach, D.J.

    1988-09-01

    One contaminant produced unintentionally during the manufacture of chlorophenols and phenoxy herbicides is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The resulting TCDD-containing wastes have been detected at many hazardous waste sites which in recent years have been in the process of remediation. Concerns about worker exposure to TCDD-contaminated soil (dust) during remediation of hazardous waste sites have produced a need for an occupational exposure limit (OEL) for TCDD. The animal toxicology data and human experience with TCDD are reviewed, and an occupational exposure limit for TCDD is proposed. The animal data support risk estimations which are based on TCDD as a nongenotoxic carcinogen. Studies on human populations have failed to demonstrate clearly any significant long-term health effects at levels to which humans have been exposed. The data indicate that an 8-hr time-weighted average limit of 2 ng/m3 is appropriate, and the associated risk would be consistent with other carcinogens at their corresponding OELs. A preliminary OEL of 0.2 ng/m3 (200 pg/m3) is recommended, however, in light of other sources of exposure because of TCDD's ubiquitousness in the environment, its unclear mechanism of action, and its rather long biological half-life in humans. This limit provides an ample margin of safety to prevent chloracne following repeated, acute exposure, and it addresses those chronic effects of TCDD observed in animal studies as well as those observed after accidental human exposure. The resulting body burden caused by chronic exposure to TCDD at the proposed OEL is examined. Its toxicological significance is compared with human tissue data and with other similarly persistent chemicals. 74 references.

  9. Weak antilocalization in thin films of the Bi2Te2.7Se0.3 solid solution

    NASA Astrophysics Data System (ADS)

    Abdullaev, N. A.; Alekperov, O. Z.; Aligulieva, Kh. V.; Zverev, V. N.; Kerimova, A. M.; Mamedov, N. T.

    2016-09-01

    A technology has been developed for the preparation of thin films of the Bi2Te2.7Se0.3 solid solution through the thermal evaporation in a vacuum using the "hot-wall" method. The high quality of the thin films thus prepared has been confirmed by the X-ray diffraction and Raman scattering data. The electron transport has been investigated over wide ranges of temperatures (1.4-300 K) and magnetic fields (up to 8 T). It has been assumed that the observed weak antilocalization is associated with the dominant contribution from the surface states of a topological insulator. The dephasing length has been estimated.

  10. Alpha3* and alpha 7 nAChR-mediated Ca2+ transient generation in IMR-32 neuroblastoma cells.

    PubMed

    Ween, Hilde; Thorin-Hagene, Kirsten; Andersen, Elisabeth; Grønlien, Jens Halvard; Lee, Chih-Hung; Gopalakrishnan, Murali; Malysz, John

    2010-10-01

    Alpha3-containing (alpha 3*) and alpha 7 nicotinic acetylcholine receptors (nAChRs) are expressed in human IMR-32 neuroblastoma cells and implicated in Ca(2+) signaling. In this study, we investigated the intracellular Ca(2+) transient generation evoked by selective activation of alpha 3* (agonist potency rank order: epibatidine>varenicline>nicotine approximately cytisine) and alpha 7 (rank order in the presence of alpha 7 positive allosteric modulator or PAM: A-795723>NS6784 approximately PNU-282987) using, respectively, varenicline and NS6784 (+alpha 7 PAM) by Ca(2+) imaging. Effects of inhibitors of nAChRs (MLA and mecamylamine), ER Ca(2+) ATPase pump (CPA and thapsigargin), Ca(2+)-induced Ca(2+) release (ryanodine and dantrolene), Ca(2+) channels (nitrendipine, diltiazem, and Cd(2+)), and removal of extracellular Ca(2+) were examined. alpha 7 PAMs, when tested in the presence of NS6784, were more active when added first, followed by the agonist, than in the reverse order. Removal of extracellular Ca(2+) - but not CPA, thapsigargin, ryanodine, dantrolene, nitrendipine, diltiazem, or Cd(2+) - diminished the alpha 7 agonist-evoked Ca(2+) transients. In contrast, only diltiazem and nitrendipine and removal of extracellular Ca(2+) inhibited the alpha 3*-mediated Ca(2+) transients. The differential effect of diltiazem and nitrendipine versus Cd(2+) was due to direct inhibition of alpha 3* nAChRs as revealed by Ca(2+) imaging in HEK-293 cells expressing human alpha 3 beta 4 nAChRs and patch clamp in IMR-32 cells. In summary, this study provides evidence that alpha 3* and alpha 7 nAChR agonist-evoked global Ca(2+) transient generation in IMR-32 cells does not primarily involve voltage-dependent Ca(2+) channels, intracellular Ca(2+) stores, or Ca(2+)-induced Ca(2+) release. These mechanisms may, however, be still involved in other forms of nAChR-mediated Ca(2+) signaling.

  11. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and long term immunologic memory.

    PubMed

    Sherr, David H

    2004-06-01

    The highlighted article by B. Paige Lawrence and Beth Vorderstrasse addresses an oft forgotten aspect of immunotoxicity, the effects of environmental toxins on immunologic memory. Here, the authors take a step towards filling that information gap by evaluating the effects of a prototypic environmental toxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), on memory responses to a real-world pathogen, influenza A virus, presented to an animal model in a physiologically relevant manner. Multiple outcomes are evaluated, the vast majority of which suggest important and long-term TCDD-induced changes in the immune system after both primary and secondary exposure to this pathogen. The implications of these studies with regard to the immuno-competence of TCDD-exposed individuals are far reaching.

  12. Josephson oscillation linewidth of ion-irradiated YBa2Cu3O7 junctions

    NASA Astrophysics Data System (ADS)

    Sharafiev, A.; Malnou, M.; Feuillet-Palma, C.; Ulysse, C.; Febvre, P.; Lesueur, J.; Bergeal, N.

    2016-07-01

    We report on the noise properties of ion-irradiated YBa2Cu3O7 Josephson junctions. This work aims at investigating the linewidth of the Josephson oscillation with a detector response experiment at ≃132 GHz. Experimental results are compared with a simple analytical model based on the Likharev-Semenov equation and the de Gennes dirty limit approximation. We show that the main source of low-frequency fluctuations in these junctions is the broadband Johnson noise and that the excess ≤ft(\\tfrac{1}{f}\\right) noise contribution does not prevail in the temperature range of interest, as reported in some other types of high-T c superconducting Josephson junctions. Finally, we discuss the interest of ion-irradiated junctions to implement frequency-tunable oscillators consisting of synchronized arrays of Josephson junctions.

  13. Surface Structure and Property Coupling of Sr3(Ru1-xMnx)2 O7

    NASA Astrophysics Data System (ADS)

    Chen, Chen; Durand, Corentin; Li, An-Ping; Zhang, Jiandi; Jin, Rongying; Plummer, Ward

    2014-03-01

    The double-layered Ruthenate Sr3Ru2O7 exhibits interesting behavior under the influence of pressure, while partial substitution of Mn for Ru generates a dramatic response in the physical properties. Even more striking is the structure-property relationship observed at the surface. Combining LEED I - V , with STM/STS and high-resolution electron energy loss spectroscopy (HREELS), we document a very unique surface phase diagram. The octahedra are tilted at the surface (not in the bulk) for low Mn doping, and the surface stabilizes and enhances the octahedra rotation, present in the bulk for Mn doping less that ~ 20%. The structure-property relationship at the surface is consistent with calculations of a tilt/rotation phase diagram (PRB 64, 020509 (2001)). Tilt distortion at the surface favors an insulating AFM ordered phase and when tilt is removed by doping of Mn the surface becomes conducting. Supported by NSF

  14. Oxygen deficiency in Ba2YCu3O7- δ: The need for a microscopic description

    NASA Astrophysics Data System (ADS)

    Batlogg, B.; Cava, R. J.

    1987-12-01

    The physical properties, such as crystal structure, resistivity, Tc and normal state susceptibility have been studied in Ba 2YCu 3O 7-δ as a function of oxygen deficiency δ. Oxygen was removed in a controlled way at relatively low temperatures employing a Zr-gettering technique. Not only do we find a second superconducting phase with Tc∼60 K and with new (short-range) crystallographic periodicity along the b-direction, but we also find that all physical properties depend on the manner in which oxygen is removed. Variations of physical properties among samples with the same over-all oxygen content can be consistently associated with the occupation of the various O-sites in the structure.

  15. Effect of hot isostatic pressing on RBa sub 2 Cu sub 3 O sub 7 superconductors

    SciTech Connect

    Sadananda, K.; Singh, A.K.; Iman, M.A.; Osofsky, M.; Le Tourneau, V.; Richards, L.E. )

    1988-09-01

    In an effort to make dense, consolidated superconductors, the hot isostatic pressing process was applied to the RBa{sub 2}Cu{sub 3}O{sub 7} system, where R is a rare-earth element. The authors have demonstrated the applicability of the hot isostatic pressing process to produce a fine-grained consolidated solid which can be cut into any desired form. The grain refinement that occurred during hot isostatic pressing was related to the fracture of coarse-grained particles during pressurization. Hot isostatic pressing combined with post-annealing increased the superconducting onset temperature to >95 K. Because of the grain refinement and the higher {Tc} achieved, the superconductor material processed by hot isostatic pressing is also expected to have higher current density, J{sub c}, than its sintered counterpart. The hot isostatic pressing process was also used successfully for the system Bi-Sr-Ca-Cu-O to make dense, bulk superconducting material.

  16. Electrochemical properties of Li7La3Zr2O12-based solid state battery

    NASA Astrophysics Data System (ADS)

    Ahn, Cheol-Woo; Choi, Jong-Jin; Ryu, Jungho; Hahn, Byung-Dong; Kim, Jong-Woo; Yoon, Woon-Ha; Choi, Joon-Hwan; Lee, Jong-Sook; Park, Dong-Soo

    2014-12-01

    The effect of moisture on the Li ion conduction of Li7La3Zr2O12 (LLZ) ceramic and the electrochemical properties of LLZ-based solid state battery was investigated using LiFePO4 (LFP) film as a cathode. LFP film was fabricated by aerosol deposition method. The secondary phase was formed in LLZ ceramic, when the specimen was exposed in humid air. With the formation of the secondary phase, the severe degradation of Li ion conduction was observed at the grain boundary. In addition, the charge and discharge capacities of LLZ-based solid state cell were quite low at room temperature, although, at 140 °C, the cell showed the high capacity. Therefore, the protection of LLZ ceramic from moisture might be required to gain the high capacity of LLZ-based solid state cell at room temperature.

  17. Josephson oscillation linewidth of ion-irradiated YBa2Cu3O7 junctions

    NASA Astrophysics Data System (ADS)

    Sharafiev, A.; Malnou, M.; Feuillet-Palma, C.; Ulysse, C.; Febvre, P.; Lesueur, J.; Bergeal, N.

    2016-07-01

    We report on the noise properties of ion-irradiated YBa2Cu3O7 Josephson junctions. This work aims at investigating the linewidth of the Josephson oscillation with a detector response experiment at ≃132 GHz. Experimental results are compared with a simple analytical model based on the Likharev–Semenov equation and the de Gennes dirty limit approximation. We show that the main source of low-frequency fluctuations in these junctions is the broadband Johnson noise and that the excess ≤ft(\\tfrac{1}{f}\\right) noise contribution does not prevail in the temperature range of interest, as reported in some other types of high-T c superconducting Josephson junctions. Finally, we discuss the interest of ion-irradiated junctions to implement frequency-tunable oscillators consisting of synchronized arrays of Josephson junctions.

  18. Biomagnification of bioassay derived 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents

    USGS Publications Warehouse

    Jones, P.D.; Ankley, G.T.; Best, D. A.; Crawford, R.; DeGalan, N.; Giesy, J.P.; Kubiak, T.J.; Ludwig, J. P.; Newsted, J.L.; Tillitt, D. E.; Verbrugge, D.A.

    1993-01-01

    In recent years contamination of the Great Lakes ecosystem with planar chlorinated hydrocarbons (PCHs) has attracted considerable concern due to their known reproductive and teratogenic effects. The H4IIE bioassay has been standardized as a means of measuring the biological potency of a PCH mixture as 2,3,7,8-tetrachloro-p-dibenzodioxin equivalents (TCDD-EQ). Using this bioassay we have investigated the biomagnification of TCDD-EQ in a semi-closed ecosystem. The biomagnification of TCDD-EQ is demonstrated and results indicate that the food chain is the major pathway for TCDD-EQ through this ecosystem. The H4IIE assay system is demonstrated to be a viable integrative measure of the total concentration of TCDD-EQ in different trophic levels.

  19. Levitation of YBa2Cu3O(7-x) superconductor in a variable magnetic field

    NASA Technical Reports Server (NTRS)

    Terentiev, Alexander N.; Kuznetsov, Anatoliy A.

    1992-01-01

    The influence of both a linear alternating and rotational magnetic field component on the levitation behavior of a YBa2Cu3O(7-x) superconductor was examined. The transition from a plastic regime of levitation to an elastic one, induced by an alternating field component, was observed. An elastic regime in contrast to a plastic one is characterized by the unique position of stable levitation and field frequency dependence of relaxation time to this position. It was concluded that the vibrations of a magnet levitated above the superconductor can induce a transition from a plastic regime of levitation to an elastic one. It was found that a rotational magnetic field component induced rotations of a levitated superconductor. Rotational frictional motion of flux lines is likely to be an origin of torque developed. A prototype of a motor based on a levitated superconductor rotor is proposed.

  20. 2,2,3,3,11,11,12,12-Octamethyl-1,4,7,10,13-pentaoxacyclohexadecane: improved synthesis and crystal structure with NaSCN

    SciTech Connect

    Loustau-Chartez, Ms. Fanny; Robeson, Rachel M; Custelcean, Radu; Sachleben, Richard A.; Bonnesen, Peter V

    2009-01-01

    An efficient synthesis of 2,2,3,3,11,11,12,12-octamethyl-1,4,7,10,13-pentaoxacyclohexadecane (1, OM16C5) is described, which affords over an order of magnitude improvement in yield over the previously reported method. The first X-ray crystal structure of 1, as a complex with NaSCN, is also reported. There is much interest in sodium-selective ionophores [1,2] for use in electrodes [1,3] and optodes [4]. One such ionophore is 2,2,3,3,11,11,12,12-octamethyl-1,4,7,10,13-pentaoxacyclohexadecane (1, octamethyl-16-crown-5 or OM16C5), which was first prepared in 1996 by Suzuki and coworkers [1]. The synthetic procedure as reported and shown in Scheme 1 involved three steps starting from pinacol. The first two steps proceeded in excellent (95%) and good (ca. 81%) yields, respectively. However, the cyclization step, involving the addition of diethylene glycol dimesylate to 2,3,3,9,9,10-hexamethyl-4,8-dioxa-2,10-undecanediol (2) using NaH in THF, proceeded poorly with a low (3.7%) isolated yield, making the overall yield for the three steps starting from pinacol approximately 2.8%. We were interested in this crown ether for alkali-metal extraction studies, and sought to improve the yield so that larger (potentially gram) quantities of material could be readily prepared. We report here a modification of the synthetic procedure that boosts the conversion of 1 from 2 over 15-fold, by using three good- to high-yielding steps that allows 1 to be obtained from 2 in a combined yield of 59%. We also report for the first time a crystal structure of 1, as the NaSCN complex

  1. Preparation, Processing and Tunneling in YBa2Cu3O7-δ-Pb Native-Barrier Structures

    NASA Astrophysics Data System (ADS)

    Frangi, Francesca; Dwir, Benjamin; James, Jonathan H.; Gauzzi, Andrea; Pavuna, Davor

    1993-06-01

    We have developed a procedure for the preparation of small (40× 40 μm2) window-type YBa2Cu3O7-δ-Pb junctions with YSZ insulator and native tunnel barrier. We present the patterning technique of the two electrodes based on photolithography and wet etching. The nature of the barrier is found to be semiconducting. The tunneling measurements show gap-like feature of YBa2Cu3O7-δ at 8.5 meV and some additional features related to Pb and YBa2Cu3O7-δ phonon spectra.

  2. Electrically tunable transport in antiferromagnetic Sr3Ir2O7

    NASA Astrophysics Data System (ADS)

    Seinige, Heidi; Wang, Cheng; Cao, Gang; Zhou, Jianshi-S.; Goodenough, John B.; Tsoi, Maxim

    Recently we demonstrated experimentally the existence of interconnections between magnetic state and transport currents in antiferromagnetic (AFM) Mott insulator Sr2IrO4. We found a very large anisotropic magnetoresistance and demonstrated a reversible resistive switching driven by high-density currents/high electric fields. These results support the feasibility of AFM spintronics, where antiferromagnets are used in place of ferromagnets, however a low Néel temperature of this material (240 K) questions any practical applications. Here we present a comparative electrical transport study of its sister compound Sr2IrO4 which has a higher transition temperature (285 K). Similar to the case of Sr2IrO4, we find a continuous reduction in the resistivity of Sr3Ir2O7 as a function of increasing electrical bias and abrupt reversible changes above a threshold bias current. We explain these results by a reduction of activation energy associated with a field-driven lattice distortion. This work was supported in part by C-SPIN, one of six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA, and by NSF Grants DMR-1207577, DMR-1265162, and DMR-1122603.

  3. 33.8 Tesla with a YBa2Cu3O7-x Superconducting Test Coil

    NASA Astrophysics Data System (ADS)

    Markiewicz, W. D.; Weijers, H. W.; Noyes, P. D.; Trociewitz, U. P.; Pickard, K. W.; Sheppard, W. R.; Jaroszynski, J. J.; Xu, A.; Larbalestier, D. C.; Hazelton, D. W.

    2010-04-01

    A small coil was made and tested for the purpose of magnet technology development for YBa2Cu3O7-x (YBCO) high field coils. The coil has a winding inner diameter of 24 mm, outer diameter of 36 mm, and length of 46 mm in a pancake wound construction of 5 double pancakes. The YBCO conductor is SuperPower SCS4050 with 2×20 μm of copper stabilizer. The coil was tested in the high field user facility of the NHMFL in a 31 T background field magnet. At this background field, the coil was operated to a current of 325 A and produced a field increment of 2.8 T for a record total field of 33.8 T. The average current density in the windings at full current was very high at 446 A/mm2. The test was complicated by the accumulation of trapped helium gas about the coil due to the diamagnetic effect of helium at high field. Even though the coil operated at elevated temperature during the high field test, the coil performance was limited by mechanical degradation and not a critical current limit.

  4. Effect of nanowires SiO2 on superconducting properties of YBa2Cu3O7-d bulks

    NASA Astrophysics Data System (ADS)

    Salem, M. K. Ben; Hannachi, E.; Slimani, Y.; Hamrita, A.; Bessais, L.; Azzouz, F. Ben; Salem, M. Ben

    2013-12-01

    The effects of SiO2 nanowires on the superconducting properties of YBa2Cu3O7-d (YBCO) compound were studied. Samples were synthesized in air using a standard solid state reaction technique by adding nanowires SiO2 up to 1wt.%. Phase analysis by X-ray diffraction (XRD), microstructure investigation by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDXS), critical current density dependence on applied magnetic field Jc(H) and electrical resistivity as a function of temperature ρ(T) were carried out to evaluate the relative performance of samples. We find that Tco does not change much (90.8-90.2 K) with the low concentration of SiO2 (≤ 0.1 wt.%) and Jc(H) is enhanced.

  5. Flux pinning and irreversibility in YBa sub 2 Cu sub 3 O sub 7 superconducting crystal

    SciTech Connect

    Sagdahl, L.T.; Gjolmesli, S.; Laegreid, T.; Fossheim, K.; Assmus, W. )

    1990-10-01

    Extensive ac-magnetic-permeability studies have been carried out on the irreversible behavior and flux dynamics in superconducting YBa{sub 2}Cu{sub 3}O{sub 7} crystals in external magnetic fields up to 7.5 T. From the analysis the irreversibility line {ital B}{sup *}({ital T}{sup *}) is found to scale as (1{minus}{ital T}{sup *}/{Tc}){sup {ital n}}, where {ital n}{approx equal}1.5 for fields higher than 1.5 T, and {ital n}{approx equal}1 for lower fields. The exponents are sensitive to the choice of {Tc}. The frequency dependence of the irreversibility temperature is carefully studied in the low-frequency region from 10 to 10{sup 5} Hz and is found to be logarithmic in the whole frequency range. The small logarithmic slope increases with increasing external field. The analysis is done within a flux-creep picture using a single-relaxation-time form for the complex permeability, and a vortex-glass model. The peak in the imaginary part of the permeability in different dc fields is successfully fitted to the predictions of the flux-creep model. A dynamical screening length is needed to account for the observed frequency dependence of the irreversibility temperature.

  6. Lithium Ion Pathway within Li7 La3 Zr2 O12 -Polyethylene Oxide Composite Electrolytes.

    PubMed

    Zheng, Jin; Tang, Mingxue; Hu, Yan-Yan

    2016-09-26

    Polymer-ceramic composite electrolytes are emerging as a promising solution to deliver high ionic conductivity, optimal mechanical properties, and good safety for developing high-performance all-solid-state rechargeable batteries. Composite electrolytes have been prepared with cubic-phase Li7 La3 Zr2 O12 (LLZO) garnet and polyethylene oxide (PEO) and employed in symmetric lithium battery cells. By combining selective isotope labeling and high-resolution solid-state Li NMR, we are able to track Li ion pathways within LLZO-PEO composite electrolytes by monitoring the replacement of (7) Li in the composite electrolyte by (6) Li from the (6) Li metal electrodes during battery cycling. We have provided the first experimental evidence to show that Li ions favor the pathway through the LLZO ceramic phase instead of the PEO-LLZO interface or PEO. This approach can be widely applied to study ion pathways in ionic conductors and to provide useful insights for developing composite materials for energy storage and harvesting. PMID:27611222

  7. Lithium Ion Pathway within Li7 La3 Zr2 O12 -Polyethylene Oxide Composite Electrolytes.

    PubMed

    Zheng, Jin; Tang, Mingxue; Hu, Yan-Yan

    2016-09-26

    Polymer-ceramic composite electrolytes are emerging as a promising solution to deliver high ionic conductivity, optimal mechanical properties, and good safety for developing high-performance all-solid-state rechargeable batteries. Composite electrolytes have been prepared with cubic-phase Li7 La3 Zr2 O12 (LLZO) garnet and polyethylene oxide (PEO) and employed in symmetric lithium battery cells. By combining selective isotope labeling and high-resolution solid-state Li NMR, we are able to track Li ion pathways within LLZO-PEO composite electrolytes by monitoring the replacement of (7) Li in the composite electrolyte by (6) Li from the (6) Li metal electrodes during battery cycling. We have provided the first experimental evidence to show that Li ions favor the pathway through the LLZO ceramic phase instead of the PEO-LLZO interface or PEO. This approach can be widely applied to study ion pathways in ionic conductors and to provide useful insights for developing composite materials for energy storage and harvesting.

  8. Epitaxial Growth of YBa2Cu3O7 Films onto LaAlO3 (100) by Using Oxalates

    NASA Astrophysics Data System (ADS)

    Dominguez, A. Bustamante; Felix, L. León; Garcia, J.; Santibañez, J. Flores; Valladares, L. De Los Santos; Gonzalez, J. C.; Anaya, A. Osorio; Pillaca, M.

    Due to the current necessity to obtain epitaxial superconductor films at low cost, we report the growth of YBa2Cu3O7 (Y123) films by chemical deposition. The procedure involved simple steps such as precipitation of stoichiometric amounts of yttrium, barium and copper acetates in oxalic acid (H2C2O4). The precursor solution was dripped onto LaAlO3 (100) substrates with the help of a Fisher pipette. The films were annealed in oxygen atmosphere during 12 h at three different temperatures: 820 °C, 840 °C and 860 °C. After 820 °C and 860 °C annealing, X-ray diffraction (XRD) analysis revealed high intensity of the (00l) reflections denoting that most of the Y123 grains were c-axis oriented. In addition, we also observed a-axis oriented grains ((h00) reflexion), minor randomly oriented grains and other phases (such as Y2BaCuO5 and CuO). In contrast, the sample treated at 840 °C, we noticed c - and a-axis oriented grains, very small amounts of randomly oriented grains without formation of other phases. From the magnetization versus temperature measurements, the critical temperatures were estimated at 70K and 90K for the samples annealed at 820 °C and 860 °C respectively.

  9. Structure of H2Ti3O7 and its evolution during sodium insertion as anode for Na ion batteries.

    PubMed

    Eguía-Barrio, Aitor; Castillo-Martínez, Elizabeth; Zarrabeitia, Maider; Muñoz-Márquez, Miguel A; Casas-Cabanas, Montse; Rojo, Teófilo

    2015-03-14

    H2Ti3O7 was prepared as a single phase material by ionic exchange from Na2Ti3O7. The complete ionic exchange was confirmed by (1)H and (23)Na solid state Nuclear Magnetic Resonance (NMR). The atomic positions of H2Ti3O7 were obtained from the Rietveld refinement of powder X-ray diffraction (PXRD) and neutron diffraction experimental data, the latter collected at two different wavelengths to precisely determine the hydrogen atomic positions in the structure. All H(+) cations are hydrogen bonded to two adjacent [Ti3O7](2-) layers leading to the gliding of the layers and lattice centring with respect to the parent Na2Ti3O7. In contrast with a previous report where protons were located in two different positions of H2Ti3O7, 3 types of proton positions were found. Two of the three types of proton are bonded to the only oxygen linked to a single titanium atom forming an H-O-H angle close to that of the water molecule. H2Ti3O7 is able to electrochemically insert Na(+). The electrochemical insertion of sodium into H2Ti3O7 starts with a solid solution regime of the C-centred phase. Then, between 0.6 and 1.2 inserted Na(+) the reaction proceeds through a two phase reaction and a plateau at 1.3 V vs. Na(+)/Na is observed in the voltage-composition curve. The second phase resembles the primitive Na2Ti3O7 cell as detected by in situ PXRD. Upon oxidation, from 0.9 to 2.2 V, the PXRD pattern remains mostly unchanged probably due to H(+) removal instead of Na(+), with the capacity quickly fading upon cycling. Conditioning H2Ti3O7 for two cycles at 0.9-2.2 V before cycling in the 0.05-1.6 V range yields similar specific capacity and better retention than the original Na2Ti3O7 in the same voltage range.

  10. Structure of H2Ti3O7 and its evolution during sodium insertion as anode for Na ion batteries.

    PubMed

    Eguía-Barrio, Aitor; Castillo-Martínez, Elizabeth; Zarrabeitia, Maider; Muñoz-Márquez, Miguel A; Casas-Cabanas, Montse; Rojo, Teófilo

    2015-03-14

    H2Ti3O7 was prepared as a single phase material by ionic exchange from Na2Ti3O7. The complete ionic exchange was confirmed by (1)H and (23)Na solid state Nuclear Magnetic Resonance (NMR). The atomic positions of H2Ti3O7 were obtained from the Rietveld refinement of powder X-ray diffraction (PXRD) and neutron diffraction experimental data, the latter collected at two different wavelengths to precisely determine the hydrogen atomic positions in the structure. All H(+) cations are hydrogen bonded to two adjacent [Ti3O7](2-) layers leading to the gliding of the layers and lattice centring with respect to the parent Na2Ti3O7. In contrast with a previous report where protons were located in two different positions of H2Ti3O7, 3 types of proton positions were found. Two of the three types of proton are bonded to the only oxygen linked to a single titanium atom forming an H-O-H angle close to that of the water molecule. H2Ti3O7 is able to electrochemically insert Na(+). The electrochemical insertion of sodium into H2Ti3O7 starts with a solid solution regime of the C-centred phase. Then, between 0.6 and 1.2 inserted Na(+) the reaction proceeds through a two phase reaction and a plateau at 1.3 V vs. Na(+)/Na is observed in the voltage-composition curve. The second phase resembles the primitive Na2Ti3O7 cell as detected by in situ PXRD. Upon oxidation, from 0.9 to 2.2 V, the PXRD pattern remains mostly unchanged probably due to H(+) removal instead of Na(+), with the capacity quickly fading upon cycling. Conditioning H2Ti3O7 for two cycles at 0.9-2.2 V before cycling in the 0.05-1.6 V range yields similar specific capacity and better retention than the original Na2Ti3O7 in the same voltage range. PMID:25683725

  11. Helical order and multiferroicity in the S =1/2 quasi-kagome system KCu3As2O7(OD)3

    NASA Astrophysics Data System (ADS)

    Nilsen, G. J.; Okamoto, Y.; Ishikawa, H.; Simonet, V.; Colin, C. V.; Cano, A.; Chapon, L. C.; Hansen, T.; Mutka, H.; Hiroi, Z.

    2014-04-01

    Several Cu2+ hydroxide minerals have been recently identified as candidate realizations of the S=1/2 kagome Heisenberg model. In this context, we have studied the distorted system KCu3As2O7(OD)3 using neutron scattering and bulk measurements. Although the distortion favors magnetic order over a spin liquid ground state, refinement of the magnetic diffraction pattern below TN1=7.05(5) K yields a complex helical structure with k =(0.77,0,0.11). This structure, as well as the spin excitation spectrum, are well described by a classical Heisenberg model with ferromagnetic nearest neighbor couplings. Multiferroicity is observed below TN1, with an unusual crossover between improper and pseudoproper behavior occurring at TN2=5.5 K. The polarization at T =2 K is P =1.5μCm-2. The properties of KCu3As2O7(OD)3 highlight the variety of physics which arise from the interplay of spin and orbital degrees of freedom in Cu2+ kagome systems.

  12. Experimental and theoretical study on diethyl-(Z)-2-(5,7-diphenyl-1,3,4-oxadiazepin-2-yl)-2-butenedioate using different levels of computational methods.

    PubMed

    Asadi, Z; Asnaashariisfahani, M B; Vessally, E; Esrafili, M D

    2015-04-01

    In this research work, diethyl-(Z)-2-(5,7-diphenyl-1,3,4-oxadiazepin-2-yl)-2-butenedioate, 7, was synthesized and characterized by FT-IR, 1H NMR, 13C NMR spectroscopy, elemental analyses and mass spectra. The reliabilities of various ab initio methods including HF and B3LYP were evaluated. The bond lengths, bond angles, dihedral angles, charge density on atoms at 7 were calculated. The ab initio calculations indicated that the B3LYP method with a 6-311++G(d,p) basis set can give accurate results. The 13C NMR and 1H NMR chemical shifts of 7 calculated and compared with the related experimental data. The HOMO, LUMO, molecular electrostatic potential (MEP) of 7 were investigated. The thermodynamic parameters and physico-chemical properties were calculated.

  13. Pseudomonas sp. CL7 from Sludge Removed 2,3,4,6-Tetrachlorophenol in Vivo and in Vitro Condition.

    PubMed

    Karn, Santosh Kumar; Reddy, M Sudhakara; Chakrabarti, Swapan Kumar

    2016-04-01

    The present research focused on 2,3,4,6-Tetrachlorophenol (2,3,4,6-TeCP) mineralizing bacterium from the sludge of pulp and paper industry and identified as Pseudomonas sp. CL7 by 16s rRNA gene sequences analysis. This isolate degraded 2,3,4,6-TeCP as indicated by stoichiometric release of chloride and biomass formation. High pressure liquid chromatography (HPLC) analysis showed that Pseudomonas sp. (CL7) was able to mineralize a higher concentration of 2,3,4,6-TeCP (600 mg/l or 2.5 mM) than any previously reported 2,3,4,6-TeCP degrading bacteria. As the concentration of 2,3,4,6-TeCP increased from 50 (0.21 mM) to 600 mg/l (2.5 mM), the reduction in the cell growth was observed and the 2,3,4,6-TeCP degradation was more than 85% in all the concentrations in the present study. CL7 was able to remove 100% of 2,3,4,6-TeCP from the sludge (in Vitro condition) when supplemented with 100 mg/l (0.42 mM) of 2,3,4,6-TeCP and grown for two weeks. This study showed that CL7 can be used for bioremediation of 2,3,4,6-TeCP. PMID:27131053

  14. Benzophenanthridines. V. Investigation of the Rodionov-Suvorov scheme. Synthesis of 3,3-diethoxycarbonyl-2-(3,4-dimethoxyphenyl)-6,7-dimethoxy-1-tetralone

    SciTech Connect

    Kyong, D.H.; Sladkov, V.I.; Suvorov, N.N.

    1988-02-20

    Triethyl 1,3-bis(3,4-dimethoxyphenyl)propane-1,2,2-tricarboxylate was synthesized by the alkylation of the lithium enolate of ethyl homoveratrate with /alpha/-bromo(3,4-dimethoxybenzyl)malonic ester. It was converted by intramolecular acylation, catalyzed by BF/sub 3/ /times/ OEt/sub 2/, into the ACD synthon for the total synthesis of benzo(c)-phenanthridine alkaloids by the Rodionov-Suvorov scheme, i.e., 3,3-diethoxy-carbonyl-2-(3,4-dimethoxyphenyl)-6,7-dimethoxy-1-tetralone. The structure of the synthesized substances agrees well with the data from elemental analysis and IR, /sup 1/H NMR, and mass spectra.

  15. High-Pressure Synthesis of Melilite-type Rare-Earth Nitridophosphates RE2P3N7 and a Ba2Cu[Si2O7]-type Polymorph.

    PubMed

    Kloß, Simon D; Weidmann, Niels; Niklaus, Robin; Schnick, Wolfgang

    2016-09-19

    High-pressure metathesis was proposed to be a gateway to the elusive class of rare-earth nitridophosphates. With this method the first ternary compounds of this class with sum formula RE2P3N7 were prepared, a melilite-type with RE = Pr, Nd, Sm, Eu, Ho, Yb (Ho2P3N7: P4̅21m, a = 7.3589(2), c = 4.9986(2) Å, Z = 2) and a Ba2Cu[Si2O7] structure type with RE = La, Ce, Pr (Pr2P3N7: monoclinic, C2/c, a = 7.8006(3), b = 10.2221(3), c = 7.7798(3) Å, β = 111.299(1)°, Z = 4). The phase relation between the two structure types was prior unknown and is here evidenced by experimental data as well as density functional theory calculations performed for the Pr2P3N7 compounds. Adequate classification of both structures types with regard to Liebau nomenclature, vertex symbol, and point symbol is made. Additionally, the tiling patterns of the monolayered structures are deducted. We demonstrate that high-pressure metathesis offers a systematic access to rare-earth nitridophosphates with an atomic ratio of P/N between 1/2 and 1/4. PMID:27579899

  16. Epitaxial YBa2Cu3O7-x nanocomposite thin films from colloidal solutions

    NASA Astrophysics Data System (ADS)

    Cayado, P.; De Keukeleere, K.; Garzón, A.; Perez-Mirabet, L.; Meledin, A.; De Roo, J.; Vallés, F.; Mundet, B.; Rijckaert, H.; Pollefeyt, G.; Coll, M.; Ricart, S.; Palau, A.; Gázquez, J.; Ros, J.; Van Tendeloo, G.; Van Driessche, I.; Puig, T.; Obradors, X.

    2015-12-01

    A methodology of general validity to prepare epitaxial nanocomposite films based on the use of colloidal solutions containing different crystalline preformed oxide nanoparticles (ex situ nanocomposites) is reported. The trifluoroacetate (TFA) metal-organic chemical solution deposition route is used with alcoholic solvents to grow epitaxial YBa2Cu3O7 (YBCO) films. For this reason stabilizing oxide nanoparticles in polar solvents is a challenging goal. We have used scalable nanoparticle synthetic methodologies such as thermal and microwave-assisted solvothermal techniques to prepare CeO2 and ZrO2 nanoparticles. We show that stable and homogeneous colloidal solutions with these nanoparticles can be reached using benzyl alcohol, triethyleneglycol, nonanoic acid, trifluoroacetic acid or decanoic acid as protecting ligands, thereby allowing subsequent mixing with alcoholic TFA solutions. An elaborate YBCO film growth analysis of these nanocomposites allows the identification of the different relevant growth phenomena, e.g. nanoparticles pushing towards the film surface, nanoparticle reactivity, coarsening and nanoparticle accumulation at the substrate interface. Upon mitigation of these effects, YBCO nanocomposite films with high self-field critical currents (J c ˜ 3-4 MA cm-2 at 77 K) were reached, indicating no current limitation effects associated with epitaxy perturbation, while smoothed magnetic field dependences of the critical currents at high magnetic fields and decreased effective anisotropic pinning behavior confirm the effectiveness of the novel developed approach to enhance vortex pinning. In conclusion, a novel low cost solution-derived route to high current nanocomposite superconducting films and coated conductors has been developed with very promising features.

  17. Oxidative stress in lake sturgeon orally exposed to 2,3,7,8-tetrachlorodibenzofuran

    SciTech Connect

    Palace, V.P.; Dick, T.A.; Brown, S.B.; Baron, C.L.; Klaverkamp, J.F. |

    1994-12-31

    Juvenile lake sturgeon were orally dosed with gelatin containing nominal concentrations of 0, 0.16 or 1.6 ng 2,3,7,8-tetrachlorodibenzofuran (TCDF)/Kg fish weight. Liver, kidney and blood were collected 10 and 27 days after exposure. Phase 1 (mixed function oxidase MFO) and Phase 2 (glucuronyltransferase) enzyme activities were determined in liver. In addition, concentrations of nonenzymatic (ascorbic acid, tocopherol, retinoids) and enzymatic (superoxide dismutase, catalase, glutathione peroxidase) antioxidant parameters were quantified in liver and kidney. TCDF concentrations were elevated in liver and kidney of both dose groups at 10 and 27 days. However, lower tissue concentrations of TCDF at 27 days compared with 10 day exposures, as well as the presence of polar metabolites in bile, suggest rapid metabolism and clearance of the contaminant. Phase 1 and Phase 2 enzyme activities were induced in a dose dependent manner with activities at the two sample periods reflecting the different TCDF concentrations. Indicators of oxidative stress responded similarly.

  18. Aerosol assisted chemical vapor deposition of superconducting YBa 2Cu 3O 7

    NASA Astrophysics Data System (ADS)

    Salazar, K. V.; Ott, K. C.; Dye, R. C.; Hubbard, K. M.; Peterson, E. J.; Coulter, J. Y.; Kodas, T. T.

    1992-08-01

    A hybrid process, aerosol-assisted chemical vapor deposotion (AACVD), is described for reproducible preparation of superconducting thin films of YBa 2Cu 3O 7-χ. The process consists of atomizing a toluene solution of the Y, Ba, and Cu tetramethylheptanedionato complexes using an aerosol generator. The aerosol is transported into a CVD reactor where solvent and precursor evaporation and deposition occur at atmospheric pressure on heated substrates. The process provides stable evaporation rates for all three precursors, yielding constant film stoichiometry throughout the deposition period and from film to film. Superconducting films may be deposited in-situ at substrate heater temperatures above 825°C, or may be formed at lower temperatures by deposition followed by post-deposition annealing at higher temperatures. The microstructure and quality of films are highly dependent on the conditions employed in deposition and in the case of films deposited below 825°C, the post-deposition annealing conditions. Superconducting films prepared by the AACVD/post-annealing process have a metallic normal state resistivity signature with a zero resistance temperature typically above 88K, and are highly c-axis oriented. Transport critical current densities measured at 75 K on polycrystalline films prepared by the AACVD process are 220 000 A/cm 2 and 84 000 A/cm 2 at self-field and 0.1 T, respectively.

  19. (R)-3'-(3-methylbenzo[b]thiophen-5-yl)spiro[1-azabicyclo[2,2,2]octane-3,5'-oxazolidin]-2'-one, a novel and potent alpha7 nicotinic acetylcholine receptor partial agonist displays cognitive enhancing properties.

    PubMed

    Tatsumi, Ryo; Fujio, Masakazu; Takanashi, Shin-ichi; Numata, Atsushi; Katayama, Jiro; Satoh, Hiroyuki; Shiigi, Yasuyuki; Maeda, Jun-ichi; Kuriyama, Makoto; Horikawa, Takashi; Murozono, Takahiro; Hashimoto, Kenji; Tanaka, Hiroshi

    2006-07-13

    Recent studies have suggested that the alpha7 nicotinic acetylcholine receptors play important roles in learning and memory. Herein, we describe our research of the structure-activity relationships (SAR) in a series of (S)-spiro[1-azabicyclo[2.2.2]octane-3,5'-oxazolidin]-2'-ones bearing various bicyclic moieties to discover novel alpha7 receptor agonists. Through a number of SAR studies on the series, we have found out that inhibition of CYP 2D6 isozyme, which was a primary obstacle for the previously identified compound, was avoidable by the introduction of bicyclic moieties. Chemical optimization of the series led to the identification of a novel and potent alpha7 nicotinic acetylcholine receptor partial agonist 23. This compound not only possessed high binding affinity (K(i) = 3 nmol/L) toward the alpha7 receptor but also showed agonistic activity even at a concentration of 0.1 micromol/L. In addition, compound 23 improved cognition in several rat models, which might suggest the potential of the alpha7 receptor partial agonist for the treatment of neurological disorders including cognitive dysfunction.

  20. The solubility and site preference of Fe3+ in Li73xFexLa3Zr2O12 garnets

    PubMed Central

    Rettenwander, D.; Geiger, C.A.; Tribus, M.; Tropper, P.; Wagner, R.; Tippelt, G.; Lottermoser, W.; Amthauer, G.

    2015-01-01

    A series of Fe3+-bearing Li7La3Zr2O12 (LLZO) garnets was synthesized using solid-state synthesis methods. The synthetic products were characterized compositionally using electron microprobe analysis and inductively coupled plasma optical emission spectroscopy (ICP-OES) and structurally using X-ray powder diffraction and 57Fe Mössbauer spectroscopy. A maximum of about 0.25 Fe3+ pfu could be incorporated in Li73xFexLa3Zr2O12 garnet solid solutions. At Fe3+ concentrations lower than about 0.16 pfu, both tetragonal and cubic garnets were obtained in the synthesis experiments. X-ray powder diffraction analysis showed only a garnet phase for syntheses with starting materials having intended Fe3+ contents lower than 0.52 Fe3+ pfu. Back-scattered electron images made with an electron microprobe also showed no phase other than garnet for these compositions. The lattice parameter, a0, for all solid-solution garnets is similar with a value of a0≈12.98 Å regardless of the amount of Fe3+. 57Fe Mössbauer spectroscopic measurements indicate the presence of poorly- or nano-crystalline FeLaO3 in syntheses with Fe3+ contents greater than 0.16 Fe3+ pfu. The composition of different phase pure Li73xFexLa3Zr2O12 garnets, as determined by electron microprobe (Fe, La, Zr) and ICP-OES (Li) measurements, give Li6.89Fe0.03La3.05Zr2.01O12, Li6.66Fe0.06La3.06Zr2.01O12, Li6.54Fe0.12La3.01Zr1.98O12, and Li6.19Fe0.19La3.02Zr2.04O12. The 57Fe Mössbauer spectrum of cubic Li6.54Fe0.12La3.01Zr1.98O12 garnet indicates that most Fe3+ occurs at the special crystallographic 24d position, which is the standard tetrahedrally coordinated site in garnet. Fe3+ in smaller amounts occurs at a general 96h site, which is only present for certain Li-oxide garnets, and in Li6.54Fe0.12La3.01Zr1.98O12 this Fe3+ has a distorted 4-fold coordination. PMID:26435549

  1. Nonaqueous slip casting of YBa2Cu3O(7-x) superconductive ceramics. Ph.D. Thesis - 1993

    NASA Technical Reports Server (NTRS)

    Hooker, Matthew W.; Taylor, Theodore D.

    1994-01-01

    This study investigates the slip casting of YBa2Cu3O(7-x) powders using nonaqueous carrier liquids and fired ceramic molds. The parameters of the process examined here include the rheological properties of YBa2Cu3O(7-x) powder dispersed in various solvent/dispersant systems, the combination of nonaqueous slips with fired ceramic molds to form the superconductive ceramics, the process-property relationships using a four-factor factorial experiment, and the applicability of magnetic fields to align the YBa2Cu3O(7-x) grains during the casting process.

  2. Tunneling characteristics of YBa 2Cu 3O 7-δ-Pb window-type Josephson junctions

    NASA Astrophysics Data System (ADS)

    Frangi, F.; Dwir, B.; Pavuna, D.

    1992-02-01

    We present the results of tunneling measurements done on window-type, native-barrier YBa 2Cu 3O 7-δ-Pb junctions. We show features in the I-V curves which are related to the gap of YBa 2Cu 3O 7-δ, as well as to the Pb and YBa 2Cu 3O 7-δ phonon spectra. The nature of barrier in these structures is found to be semi-conducting. We can also see the asymmetry in the tunneling curves.

  3. Drinking-water criteria document for 2,3,7,8-tetrachlorodibenzo-p-dioxin. Draft report

    SciTech Connect

    Not Available

    1988-04-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) is one of the most toxic and environmentally stable tricyclic aromatic compounds belonging to chlorinated dibenzo-p-dioxins. 2,3,7,8-TCDD has been demonstrated to be teratogenic in rats, mice and rabbits, and feticidal in monkeys. The major toxic signs and terata observed were cleft palate in mice, edema, hemorrhage, and kidney anomalies in rats and extra ribs in rabbits. Some epidemiological studies have indicated a possible teratogenic effect in humans, but the evidence is not sufficient to reach a firm conclusion.

  4. Phase diagrams of the systems Mn(VO{sub 3}){sub 2}-M(VO{sub 3}){sub 2} and Mn{sub 2}V{sub 2}O{sub 7}-M{sub 2}V{sub 2}O{sub 7} (M = Sr, Ba)

    SciTech Connect

    Zhuravlev, V.D.; Surat, L.L.; Velikodnyi, Yu.A.

    1994-12-01

    In this paper, the authors report results on the phase relations in meta- and pyrovanadate binary systems containing manganese, strontium, or barium and their phase diagrams. Using powder X-ray diffraction and differential thermal analysis, we studied the phase diagrams of the systems Mn(VO{sub 3}){sub 2}-M(VO){sub 3}{sub 2} and Mn{sub 2}V{sub 2}-O{sub 7}-M{sub 2}V{sub 2}O{sub 7} (M=Sr,Ba) in air. Mn{sub 1-x}Sr{sub x}(VO{sub 3}){sub 2}solid solutions and three new compounds, BaMnV{sub 2}O{sub 7}, SrMnV{sub 2}O{sub 7}, and Sr{sub 3}Mn(V{sub 2}O{sub 7}){sub 2}, were found, and their thermal behavior was studied.

  5. In vivo neurometabolic profiling in patients with spinocerebellar ataxia types 1, 2, 3, and 7.

    PubMed

    Adanyeguh, Isaac M; Henry, Pierre-Gilles; Nguyen, Tra M; Rinaldi, Daisy; Jauffret, Celine; Valabregue, Romain; Emir, Uzay E; Deelchand, Dinesh K; Brice, Alexis; Eberly, Lynn E; Öz, Gülin; Durr, Alexandra; Mochel, Fanny

    2015-04-15

    Spinocerebellar ataxias (SCAs) belong to polyglutamine repeat disorders and are characterized by a predominant atrophy of the cerebellum and the pons. Proton magnetic resonance spectroscopy ((1) H MRS) using an optimized semiadiabatic localization by adiabatic selective refocusing (semi-LASER) protocol was performed at 3 T to determine metabolite concentrations in the cerebellar vermis and pons of a cohort of patients with SCA1 (n=16), SCA2 (n=12), SCA3 (n=21), and SCA7 (n=12) and healthy controls (n=33). Compared with controls, patients displayed lower total N-acetylaspartate and, to a lesser extent, lower glutamate, reflecting neuronal loss/dysfunction, whereas the glial marker, myoinositol (myo-Ins), was elevated. Patients also showed higher total creatine as reported in Huntington's disease, another polyglutamine repeat disorder. A strong correlation was found between the Scale for the Assessment and Rating of Ataxia and the neurometabolites in both affected regions of patients. Principal component analyses confirmed that neuronal metabolites (total N-acetylaspartate and glutamate) were inversely correlated in the vermis and the pons to glial (myo-Ins) and energetic (total creatine) metabolites, as well as to disease severity (motor scales). Neurochemical plots with selected metabolites also allowed the separation of SCA2 and SCA3 from controls. The neurometabolic profiles detected in patients underlie cell-specific changes in neuronal and astrocytic compartments that cannot be assessed by other neuroimaging modalities. The inverse correlation between metabolites from these two compartments suggests a metabolic attempt to compensate for neuronal damage in SCAs. Because these biomarkers reflect dynamic aspects of cellular metabolism, they are good candidates for proof-of-concept therapeutic trials. © 2015 International Parkinson and Movement Disorder Society.

  6. Near-infrared emissions from Yb3+-doped CeO2 and Ce2Si2O7 films based on silicon substrates subjected to thermal treatment

    NASA Astrophysics Data System (ADS)

    Mu, Guangyao; Wang, Shenwei; Li, Ling; Yin, Xue; Huang, Miaoling; Yi, Lixin

    2016-05-01

    Photoluminescence properties of Yb3+-doped CeO2 films annealed in different atmospheres were investigated. CeO2:Yb3+ films were deposited by electron-beam evaporation technique. Near-infrared emission around 970 nm was observed after annealing the films both in air and in Ar-H2 atmosphere, which is attributed to the Yb3+:2F5/22F7/2 transition. Optimization of the Yb3+ concentration for the 970 nm luminescence yield was also investigated. Characterized by different methods, Ce2Si2O7 was formed in the films annealed in reducing atmosphere, which was expected to be more applicable for the silicon-based optoelectronic applications.

  7. [The neuroprotective action of enantiomers and racemate of 2-(3,7-dioxo-2,4,6,8-tetraazabicyclo[3.3.0]oct-2-yl)-4-methylthiobutanoic acid].

    PubMed

    Kravchenko, A N; Baranov, V V; Anikina, L V; Vikharev, Iu B; Bushmarinov, I S; Neliubina, Iu V

    2012-01-01

    Neurotropic, neuroprotective and antioxidant actions of the enantiomers and the racemate of 2-(3,7-dioxo-2,4,6,8-tetraazabicyclo[3.3.0]oct-2-yl)-4-methylthiobutanoic acid were investigated. Only (+)-(S)-2-(3,7-dioxo-2,4,6,8-tetraazabicyclo[3.3.0]oct-2-yl)-4-methylthiobutanoic acid was found to have neuroprotective properties. A distereoselective synthesis of enantiomers and racemate was performed by condensations of (S), (R) and (R,S)-N-carbamoylmethionines with 4,5-dihydroxyimidazolidin-2-one (DHI), respectively. By the X-ray method, the major racemate was proved to crystallize from water as a conglomerate. No antioxidant activity was revealed.

  8. Space station systems analysis study. Part 2, volume 3: Appendixes, Book 2: Supporting data (7 through 18)

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Topics discussed include: (1) design considerations for a MARS sample return laboratory module for space station investigations; (2) crew productivity as a function of work shift arrangement; (3) preliminary analysis of the local logistics problem on the space construction base; (4) mission hardware construction operational flows and timelines; (5) orbit transfer vehicle concept definition; (6) summary of results and findings of space processing working review; (7) crew and habitability subsystem (option L); (8) habitability subsystem considerations for shuttle tended option L; (9) orbiter utilization in manned sortie missions; (10) considerations in definition of space construction base standard module configuration (option L); (11) guidance, control, and navigation subsystems; and (12) system and design tradeoffs.

  9. Superconducting YBa2Cu3O7 films for novel (opto)electronic device structures

    NASA Astrophysics Data System (ADS)

    Pavuna, D.; Dwir, B.; Gauzzi, A.; James, J. H.; Kellett, B. J.

    1991-02-01

    This short overview briefly summarizes the most important parameters for successful preparation and associated properties of thin films of YBa2Cu3O(7-delta) (YBCO) superconductors. The principles are illustrated by using the example of monotarget ion beam sputtering technique: YBCO films grown in situ on SrTiO3 show Tc(onset) = 92 K and Tco = 91 K. Magnetron sputtering, E-beam evaporation, laser ablation and molecular beam epitaxy are discussed. In situ ion beam sputtering of YBCO on Si and GaAs substrates with intermediate, conducting Indium Tin Oxide (ITO) buffer layers is also presented. Uniform, textured YBCO films on ITO exhibit Tc(onset) at 92 K and Tco at 68 K and 60 K on Si and GaAs substrates, respectively; the latter is the highest Tc reported on GaAs. YBCO/ITO films exhibit metallic resistivity behavior. Finally, the performance of a simple optical bolometer demonstrated on YBCO films and the results of tunneling measurements on the window-type YBCO-Pb tunnel junctions are discussed.

  10. Photoresponse of YBa2Cu3O(7-delta) granular and epitaxial superconducting thin films

    NASA Technical Reports Server (NTRS)

    Valco, G. J.; Claspy, P.; Warner, J. D.; Varaljay, N.; Bhasin, K. B.

    1990-01-01

    The response is reported of thin films of YBa2Cu3O(7-delta) with either a very grainy or a smooth epitaxial morphology to visible radiation. SrTiO3 substrates were employed for both types of films. The grainy films were formed by sequential multi-layer electron beam evaporation while the epitaxial films were formed by laser ablation. Both films were patterned into H shaped detectors via a negative photolithographic process employing a Br/ethanol etchant. The bridge region of the H was 50 microns wide. The patterned films formed by laser ablation and sequential evaporation had critical temperatures of 74 K and 72 K respectively. The bridge was current biased and illuminated with chopped He-Ne laser radiation and the voltage developed in response to the illumination was measured. A signal was detected only above the critical temperature and the peak of the response coincided with the resistive transition for both types of films although the correspondence was less exact for the grainy film. The details of the responses and their analysis are presented.

  11. Structure and Stoichiometry in Supervalent Doped Li7La3 Zr2O12

    DOE PAGES

    Mukhopadhyay, Saikat; Thompson, Travis; Sakamoto, Jeff; Huq, Ashfia; Wolfenstine, Jeff; Allen, Jan L.; Bernstein, Noam; Stewart, Derek A.; Johannes, M. D.

    2015-04-20

    The oxide garnet material Li7La3 Zr2O12 shows remarkably high ionic conductivity when doped with supervalent ions that are charge compensated by Li vacancies and is currently one of the best candidates for development of a technologically relevant solid electrolyte. Determination of optimal dopant concentration, however, has remained a persistent problem due to the extreme difficulty of establishing the actual (as compared to nominal) stoichiometry of intentionally doped materials and by the fact that it is still not entirely clear what level of lattice expansion/contraction best promotes. ionic diffusion. By combining careful synthesis, neutron diffraction, high-resolution X-ray diffraction (XRD), Raman measurements,more » and density functional theory calculations, we show that structure and stoichiometry are intimately related such that the former can in many cases be used as a gauge of the latter. We show that different Li-vacancy creating supervalent ions (Al3+ vs Ta5+) affect the structure very differently, both in terms of the lattice constant, which is easily measurable, and hi terms of the local structure, which can be difficult or impossible to access experimentally but may have important ramifications for conduction. We carefully correlate the lattice constant to dopant type/concentration via Vegard's law and then further correlate these quantities to relevant local structural parameters. In conclusion, our work opens the possibility of developing a codopant scheme that optimizes the Li vacancy concentration and the lattice size simultaneously.« less

  12. Free energy of formation of Cs 3PuCl 6 and CsPu 2Cl 7

    NASA Astrophysics Data System (ADS)

    Williamson, M. A.; Kleinschmidt, P. D.

    The free energy, enthalpy and entropy of formation of the compounds Cs 3PuCl 6 and CsPu 2Cl 7 have been determined by measuring the sublimation pressures for the reactions CsCl( s) / aiCsCl( g), {2}/{5}Cs 3PuCl 6(s) /ai {1}/{5}CsPu 2Cl 7(s) + CsCl(g) , and CsPu2Cl7( s) / ai 2 PuCl3( s) + CsCl( g). The pressures are measured using Knudsen effusion mass spectrometry over the temperature range 600 to 850 K. For the formation of Cs 3PuCl 6 from CsCl and PuCl 3, ΔG0298 = -77.3 ± 8.5 kJ/ mol, ΔH0298 = -82.1 ± 7.8 kJ/ mol, and ΔS0298 = -16.2 ± 10.9 J/ Kmol. For CsPu 2Cl 7, ΔG0298 = -39.4 ± 3.5 kJ/ mol, ΔH0298 = -40.8 ± 3.2 kJ/ mol, and ΔS0298 = -4.6 ± 4.2 J/ Kmol.

  13. Ethyl (Z)-2-(2-fluoro­benzyl­idene)-7-methyl-3-oxo-5-phenyl-3,5-dihydro-2H-thia­zolo[3,2-a]pyrimidine-6-carboxyl­ate

    PubMed Central

    Zhao, Cheng-Guang; Hu, Jie; Zhang, Ya-Li; Zhang, Jing; Yang, Shu-Lin

    2011-01-01

    The title compound, C23H19FN2O3S, a fused-pyrimidine derivative, displays dihedral angles between the thia­zole ring and the benzene ring and substituted benzene ring of 7.10 (14) and 3.48 (12)°, respectively. The dihydro­pyrimidine ring adopts a flattened boat conformation. The olefinic double bond is in a Z configuration. PMID:22220026

  14. Fabrication and critical current density analysis of YBa2Cu3O7+(BaSnO3)‧/YBa2Cu3O7+(BaSnO3)″ multilayer films

    NASA Astrophysics Data System (ADS)

    Horide, Tomoya; Sakamoto, Nobuhiro; Ichinose, Ataru; Matsumoto, Kaname

    2016-08-01

    Multilayers (MLs) comprising of YBa2Cu3O7(YBCO)+BaSnO3(BSO) layers with different BSO content were fabricated, and their critical current density (J c) was measured to understand influence of ML structure on vortex pinning. Elongated and segmented nanorods were observed in the MLs, and ab-plane aligned nanoparticles appeared depending on BSO content. When BSO formed only elongated and segmented nanorods in MLs, J c exhibited a linear relationship between J c in the single layer films. On the other hand, when MLs contained ab-plane aligned nanoparticles in addition to nanorods, J c decreased with lower-J c-layer fraction more rapidly. These results suggest that J c was degraded due to easy vortex flow along the lower-J c-layers, and that the acceleration of vortex motion depended on the type of lower-J c-layers. Vortex behavior which is not observed in conventional systems such as single layer films and bulk samples is strongly expected in MLs, since fine tuning of pinning center structure is possible.

  15. Characterization of MBa2Cu3O7-x thin films by Raman microspectroscopy.

    PubMed

    Venkataraman, Kartik; Baurceanu, Roxanne; Maroni, Victor A

    2005-05-01

    Thin film embodiments of MBa2Cu3O7-x (MBCO, M = yttrium or a rare-earth metal) prepared by several different deposition methods on a variety of substrates were investigated by Raman microspectroscopy. Several of the unique characterization capabilities of Raman spectroscopy in the analysis of MBCO thin films are highlighted by the results of these investigations. The Raman active phonons of the orthorhombic and tetragonal forms of MBCO that are most useful for characterization of textured MBCO films are diagrammed and discussed. A rapid procedure for qualitative texture mapping of MBCO thin films using Raman microscopy techniques is presented, and a new approach for investigating phase separation at the sub-micrometer level in MBCO thin films based on curve resolution of the MBCO Cu2 phonon is described. The assignment of a particular feature often observed in Raman spectra of MBCO films to cation disorder is reinforced by results of a cation substitution study. The depth of penetration of the laser into MBCO films and the type of information that can be obtained by varying the extent of defocusing of the laser are also discussed. PMID:15969809

  16. Flat YBa 2Cu 3O 7- x layers for planar tunnel-device technology

    NASA Astrophysics Data System (ADS)

    Klemenz, C.; Scheel, H. J.

    1996-02-01

    The conditions for achieving extremely flat YBa 2Cu 3O 7- x (YBCO) surfaces with large interstep distances as required for a reliable planar HTSC tunnel-device technology are analyzed. Considerations of thermodynamics, kinetics and transport of the growth species show that by liquid phase epitaxy (LPE) it is possible to achieve such flat YBCO surfaces, which is experimentally proven. Specifically, in LPE the growth from relatively concentrated solutions occurs at high temperatures near thermodynamic equilibrium. The small supersaturation (of < 0.17°C) required for obtaining step distances of more than 10 μm has been calculated by using the heat of solution from the measured solubility curve and the theoretical treatment of the experimental sufface features. Jackson's α factors (roughness parameter) are derived for a- and c-oriented YBCO films and explain the different degree of polygonization of the observed growth spirals. The concentrations of YBCO in physical vapour deposition (PVD) and in metal-organic chemical vapour deposition (MOCVD) are very small and the supersaturations at least 10 2 times higher than in LPE. This, together with the thermodynamic stability limit (temperature, oxygen partial pressure), sets an inherent limit to the interstep distance in PVD and MOCVD, thus limiting the achievable flatness of vapour-grown YBCO layers.

  17. Point defects in YBa2Cu3O7-x studied using positron annihilation

    NASA Astrophysics Data System (ADS)

    Chudy, Michal; Eisterer, M.; Weber, H. W.; Veterníková, J.; Sojak, S.; Slugeň, V.

    2012-07-01

    Fast neutron irradiation is a powerful technique for introducing additional pinning centers into high temperature superconductors. The spherical defects with sizes of a few nanometers are considered to be effective pinning centers, enhancing Jc. Their morphology is well-known and has already been investigated by several authors in great detail. However, only very little is known about the nature and density of smaller and point defects, which are invisible in transmission electron microscopy. Positron annihilation lifetime spectroscopy was applied to investigate the nature and the concentration of small point-like defects. In this work, the influence of small point defects, such as vacancies and vacancy clusters, on the superconducting properties of YBa2Cu3O7-x bulks was studied; these were introduced by irradiation in the TRIGA Mark II reactor in Vienna. Jc and Tc measurements were performed prior to and after each irradiation step. The samples were irradiated up to a fast neutron ( > 0.1 MeV) fluence of 6 × 1021 m-2. The two kinds of defects—the large collision cascades and the small point-like defects—contribute to the decrease of Tc as well as to the Jc enhancement in astonishingly similar ways.

  18. 7 CFR 7.3 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Definitions. 7.3 Section 7.3 Agriculture Office of the Secretary of Agriculture SELECTION AND FUNCTIONS OF AGRICULTURAL STABILIZATION AND CONSERVATION STATE, COUNTY AND COMMUNITY COMMITTEES § 7.3 Definitions. The terms defined in part 719 of this title...

  19. Phase relations in the K 2W 2O 7-K 2WO 4-KPO 3-Bi 2O 3 system and structure of K 6.5Bi 2.5W 4P 6O 34

    NASA Astrophysics Data System (ADS)

    Terebilenko, K. V.; Zatovsky, I. V.; Baumer, V. N.; Ogorodnyk, I. V.; Slobodyanik, N. S.; Shishkin, O. V.

    2008-09-01

    The phase relations in the cross-section of the K 2W 2O 7-K 2WO 4-KPO 3 containing 15 mol% Bi 2O 3 were undertaken using flux method. Crystallization fields of K 6.5Bi 2.5W 4P 6O 34, K 2Bi(PO 4)(WO 4), Bi 2WO 6, KBi(WO 4) 2 and their cocrystallization areas were identified. Novel phase K 6.5Bi 2.5W 4P 6O 34 was characterized by single-crystal X-ray diffraction: sp. gr. P-1, a=9.4170(5), b=9.7166(4), c=17.6050(7) Å, α=90.052(5)°, β=103.880(5)° and γ=90.125(5)°. It has a layered structure, which contains {K 7Bi 5W 8P 12O 68} ∞ layers stacked parallel to ab plane and sheets composed by potassium atoms separating these layers. Sandwich-like {K 7Bi 5W 8P 12O 68} ∞ layers are assembled from [W 2P 2O 13] ∞ and [BiPO 4] ∞ building units, and are penetrated by tunnels with K/Bi atoms inside. FTIR-spectra of K 2Bi(PO 4)(WO 4) and K 6.5Bi 2.5W 4P 6O 34 were discussed on the basis of factor group theory.

  20. A role for the Perlman syndrome exonuclease Dis3l2 in the Lin28-let-7 pathway

    PubMed Central

    Chang, Hao-Ming; Triboulet, Robinson; Thornton, James E.; Gregory, Richard I.

    2013-01-01

    The pluripotency factor Lin28 blocks the expression of let-7 microRNAs (miRNAs) in undifferentiated cells during development and functions as an oncogene in a subset of cancers1. Lin28 binds to let-7 precursor RNAs and recruits 3′ terminal uridylyl transferases (TUTases) to selectively inhibit let-7 biogenesis2–4. Uridylated pre-let-7 is refractory to processing by Dicer and is rapidly degraded by an unknown ribonuclease5. Here we identify Dis3l2 as the 3′-5′ exonuclease responsible for the decay of uridylated pre-let-7. Biochemical reconstitution assays reveal that 3′ oligouridylation stimulates Dis3l2 activity in vitro, and knockdown of Dis3l2 in mouse embryonic stem cells leads to the stabilization of pre-let-7. Our study establishes 3′ oligouridylation as an RNA decay signal for Dis3l2 and identifies the first physiological RNA substrate of this novel exonuclease that is mutated in the Perlman syndrome of fetal overgrowth and predisposition to Wilms’ tumor6. PMID:23594738

  1. Sputter-induced grain boundary junctions in YBa2Cu3O7 - x thin films on MgO

    NASA Astrophysics Data System (ADS)

    Vuchic, B. V.; Merkle, K. L.; Dean, K. A.; Buchholz, D. B.; Chang, R. P. H.; Marks, L. D.

    1995-03-01

    A low voltage argon ion sputter technique was used to form grain boundary junctions in YBa2Cu3O7-x thin films on MgO. The YBa2Cu3O7-x thin film grown on a pre-sputtered region of MgO was rotated 45° about the [001] axis relative to the YBa2Cu3O7-x thin film grown on an adjacent unsputtered region of the substrate. YBa2Cu3O7-x thin films were grown using pulsed organometallic beam epitaxy (POMBE). The current-voltage and resistance-temperature characteristics of individual grain boundary junctions demonstrated weak-link-type behavior. Sputter-induced 45° grain boundary junctions are advantageous in device applications because they are planar and simple to form in many configurations.

  2. Raman spectra and dielectric studies in Ti substituted Bi2 (Zn2/3Nb4/3)O7 pyrochlores

    NASA Astrophysics Data System (ADS)

    Kumar, Aditya; Singh, Manoj K.; Singh, Gulab; Sudheendran, K.; Raju, K. C. James

    2016-05-01

    Bi2Zn2/3-x/3Nb4/3-2x/3TixO7 (m - BZNT) with x = 0 to 0.4 were synthesized in the conventional solid state route. The dielectric constants of these ceramics at microwave frequencies are found to be increasing from 70 to 114 when x increased from 0 to 0.4. Raman scattering studies were carried out to investigate the effect of Ti4+ substitution on the dielectric properties of Bi2 (Zn2/3Nb4/3)O7 (m-BZN) ceramics. The observed Raman peaks in the m-BZNT are slightly shifted towards lower frequency in comparison to that of m-BZN clearly indicated that the Ti4+ ions are indeed occupying substitution sites in the host m - BZN. The anomalous change in intensity and full with at half maxima (FWHM) of Raman modes at 749 and 847 cm-1 suggest change in oxygen octahedral closely related to dielectric properties of m-BZNT.

  3. Identification of a novel class of selective Tpl2 kinase inhibitors: 4-Alkylamino-[1,7]naphthyridine-3-carbonitriles.

    PubMed

    Kaila, Neelu; Green, Neal; Li, Huan-Qiu; Hu, Yonghan; Janz, Kristin; Gavrin, Lori Krim; Thomason, Jennifer; Tam, Steve; Powell, Dennis; Cuozzo, John; Hall, J Perry; Telliez, Jean-Baptiste; Hsu, Sang; Nickerson-Nutter, Cheryl; Wang, Qin; Lin, Lih-Ling

    2007-10-01

    We have previously reported the discovery and initial SAR of the [1,7]naphthyridine-3-carbonitriles and quinoline-3-carbonitriles as Tumor Progression Loci-2 (Tpl2) kinase inhibitors. In this paper, we report new SAR efforts which have led to the identification of 4-alkylamino-[1,7]naphthyridine-3-carbonitriles. These compounds show good in vitro and in vivo activity against Tpl2 and improved pharmacokinetic properties. In addition they are highly selective for Tpl2 kinase over other kinases, for example, EGFR, MEK, MK2, and p38. Lead compound 4-cycloheptylamino-6-[(pyridin-3-ylmethyl)-amino]-[1,7]naphthyridine-3-carbonitrile (30) was efficacious in a rat model of LPS-induced TNF-alpha production.

  4. Identification of a novel class of selective Tpl2 kinase inhibitors: 4-Alkylamino-[1,7]naphthyridine-3-carbonitriles.

    PubMed

    Kaila, Neelu; Green, Neal; Li, Huan-Qiu; Hu, Yonghan; Janz, Kristin; Gavrin, Lori Krim; Thomason, Jennifer; Tam, Steve; Powell, Dennis; Cuozzo, John; Hall, J Perry; Telliez, Jean-Baptiste; Hsu, Sang; Nickerson-Nutter, Cheryl; Wang, Qin; Lin, Lih-Ling

    2007-10-01

    We have previously reported the discovery and initial SAR of the [1,7]naphthyridine-3-carbonitriles and quinoline-3-carbonitriles as Tumor Progression Loci-2 (Tpl2) kinase inhibitors. In this paper, we report new SAR efforts which have led to the identification of 4-alkylamino-[1,7]naphthyridine-3-carbonitriles. These compounds show good in vitro and in vivo activity against Tpl2 and improved pharmacokinetic properties. In addition they are highly selective for Tpl2 kinase over other kinases, for example, EGFR, MEK, MK2, and p38. Lead compound 4-cycloheptylamino-6-[(pyridin-3-ylmethyl)-amino]-[1,7]naphthyridine-3-carbonitrile (30) was efficacious in a rat model of LPS-induced TNF-alpha production. PMID:17664070

  5. Crystal structure of (1S,3R,8R,9R)-2,2-di-chloro-3,7,7-tri-methyl-10-methylenetri-cyclo-[6.4.0.0(1,3)]dodecan-9-ol.

    PubMed

    Benzalim, Ahmed; Auhmani, Aziz; Bimoussa, Abdoullah; Ait Itto, My Youssef; Daran, Jean-Claude; Auhmani, Abdelwahed

    2016-08-01

    The title compound, C16H24Cl2O, was synthesized by treating (1S,3R,8S,9R,10S)-2,2-di-chloro-3,7,7,10-tetra-methyl-9,10-ep-oxy-tri-cyclo-[6.4.0.0(1,3)]dodecane with a concentrated solution of hydro-bromic acid. It is built up from three fused rings: a cyclo-heptane ring, a cyclo-hexyl ring bearing alkene and hy-droxy substituents, and a cyclo-propane ring bearing two chlorine atoms. The asymmetric unit contains two mol-ecules linked by an O-H⋯O hydrogen bond. In the crystal, further O-H⋯O hydrogen bonds build up an R 4 (4)(8) cyclic tetra-mer. One of the mol-ecules presents disorder that affects the seven-membered ring. In both mol-ecules, the six-membered rings display a chair conformation, whereas the seven-membered rings display conformations inter-mediate between boat and twist-boat for the non-disordered mol-ecule and either a chair or boat and twist-boat for the disordered mol-ecule owing to the disorder. The absolute configuration for both mol-ecules is 1S,3R,8R,9R and was deduced from the chemical pathway and further confirmed by the X-ray structural analysis. PMID:27536404

  6. Large area ion beam sputtered YBa2Cu3O(7-delta) films for novel device structures

    NASA Astrophysics Data System (ADS)

    Gauzzi, A.; Lucia, M. L.; Kellett, B. J.; James, J. H.; Pavuna, D.

    1992-03-01

    A simple single-target ion-beam system is employed to manufacture large areas of uniformly superconducting YBa2Cu3O(7-delta) films which can be reproduced. The required '123' stoichiometry is transferred from the target to the substrate when ion-beam power, target/ion-beam angle, and target temperature are adequately controlled. Ion-beam sputtering is experimentally demonstrated to be an effective technique for producing homogeneous YBa2Cu3O(7-delta) films.

  7. Bioinspired Hydrogenase Models: The Mixed-Valence Triiron Complex [Fe3(CO)7(μ-edt)2] and Phosphine Derivatives [Fe3(CO)7–x(PPh3)x(μ-edt)2] (x = 1, 2) and [Fe3(CO)5(κ2-diphosphine)(μ-edt)2] as Proton Reduction Catalysts

    PubMed Central

    2014-01-01

    The mixed-valence triiron complexes [Fe3(CO)7–x(PPh3)x(μ-edt)2] (x = 0–2; edt = SCH2CH2S) and [Fe3(CO)5(κ2-diphosphine)(μ-edt)2] (diphosphine = dppv, dppe, dppb, dppn) have been prepared and structurally characterized. All adopt an anti arrangement of the dithiolate bridges, and PPh3 substitution occurs at the apical positions of the outer iron atoms, while the diphosphine complexes exist only in the dibasal form in both the solid state and solution. The carbonyl on the central iron atom is semibridging, and this leads to a rotated structure between the bridged diiron center. IR studies reveal that all complexes are inert to protonation by HBF4·Et2O, but addition of acid to the pentacarbonyl complexes results in one-electron oxidation to yield the moderately stable cations [Fe3(CO)5(PPh3)2(μ-edt)2]+ and [Fe3(CO)5(κ2-diphosphine)(μ-edt)2]+, species which also result upon oxidation by [Cp2Fe][PF6]. The electrochemistry of the formally Fe(I)–Fe(II)–Fe(I) complexes has been investigated. Each undergoes a quasi-reversible oxidation, the potential of which is sensitive to phosphine substitution, generally occurring between 0.15 and 0.50 V, although [Fe3(CO)5(PPh3)2(μ-edt)2] is oxidized at −0.05 V. Reduction of all complexes is irreversible and is again sensitive to phosphine substitution, varying between −1.47 V for [Fe3(CO)7(μ-edt)2] and around −1.7 V for phosphine-substituted complexes. In their one-electron-reduced states, all complexes are catalysts for the reduction of protons to hydrogen, the catalytic overpotential being increased upon successive phosphine substitution. In comparison to the diiron complex [Fe2(CO)6(μ-edt)], [Fe3(CO)7(μ-edt)2] catalyzes proton reduction at 0.36 V less negative potentials. Electronic structure calculations have been carried out in order to fully elucidate the nature of the oxidation and reduction processes. In all complexes, the HOMO comprises an iron–iron bonding orbital localized between the two iron

  8. Boson localization and universality in YBa2Cu(3-x)M(x)O(7-delta)

    NASA Technical Reports Server (NTRS)

    Kallio, A.; Apaja, V.; Poykko, S.

    1995-01-01

    We consider a two component mixture of charged fermions on neutralizing background with all sign combinations and arbitrarily small mass ratios. In the two impurity limit for the heavier component we show that the pair forms a bound state for all charge combinations. In the lowest order approximation we derive a closed form expression Veff(r) for the binding potential which has short-range repulsion followed by attraction. In the classical limit, when the mass of embedded particles is large m2 much greater than m, we can calculate from Veff(r) also the cohesive energy E and the bond length R of a metallic crystal such as lithium. The lowest order result is R = 3.1 A, E = -0.9 eV, not entirely different from the experimental result for lithium metal. The same interaction for two holes on a parabolic band with m2 greater than m gives the quantum mechanical bound state which one may interpret as a boson or local pair in the case of high-Te and heavy fermion superconductors. We also show that for compounds of the type YBa2Cu(3 - x)M(x)O(7 - delta) one can understand most of the experimental results for the superconducting and normal states with a single temperature dependent boson breaking function f(T) for each impurity content x governing the decay of bosons into pairing fermions. In the normal state f(T) turns out to be a linear, universal function, independent of the impurity content I and the oxygen content delta. We predict with universality a depression in Tc(x) with slight down bending in agreement with experiment. As a natural consequence of the model the bosons become localized slightly above Tc due to the Wigner crystallization, enhanced with lattice local field minima. The holes remain delocalized with a linearly increasing concentration in the normal state, thus explaining the rising Hall density. The boson localization temperature T(sub BL) shows up as a minimum in the Hall density R(sub ab)(exp -1). We also give explanation for very recently observed

  9. Elastic Properties of the Solid Electrolyte Li7La3Zr2O12 (LLZO)

    SciTech Connect

    Yu, Seungho; Schmidt, Robert D.; Garcia-mendez, Regina; Herbert, Erik G.; Dudney, Nancy J.; Wolfenstine, Jeff; Sakamoto, Jeff; Seigel, Donald

    2015-12-16

    The oxide known as LLZO, with nominal composition Li7La3Zr2O12, is a promising solid electrolyte for Li-based batteries due to its high Li-ion conductivity and chemical stability with respect to lithium. Solid electrolytes may also enable the use of metallic Li anodes by serving as a physical barrier that suppresses dendrite initiation and propagation during cycling. Prior linear elasticity models of the Li electrode/solid electrolyte interface suggest that the stability of this interface is highly dependent on the elastic properties of the solid separator. For example, dendritic suppression is predicted to be enhanced as the electrolyte s shear modulus increases. In the present study a combination of first-principles calculations, acoustic impulse excitation measurements, and nanoindentation experiments are used to determine the elastic constants and moduli for highconductivity LLZO compositions based on Al and Ta doping. The calculated and measured isotropic shear moduli are in good agreement and fall within the range of 56-61 GPa. These values are an order of magnitude larger than that for Li metal and far exceed the minimum value ( 8.5 GPa) believed to be necessary to suppress dendrite initiation. These data suggest that LLZO exhibits sufficient stiffness to warrant additional development as a solid electrolyte for Li batteries.

  10. Elastic Properties of the Solid Electrolyte Li7La3Zr2O12 (LLZO)

    DOE PAGES

    Yu, Seungho; Schmidt, Robert D.; Garcia-mendez, Regina; Herbert, Erik G.; Dudney, Nancy J.; Wolfenstine, Jeff; Sakamoto, Jeff; Seigel, Donald

    2015-12-16

    The oxide known as LLZO, with nominal composition Li7La3Zr2O12, is a promising solid electrolyte for Li-based batteries due to its high Li-ion conductivity and chemical stability with respect to lithium. Solid electrolytes may also enable the use of metallic Li anodes by serving as a physical barrier that suppresses dendrite initiation and propagation during cycling. Prior linear elasticity models of the Li electrode/solid electrolyte interface suggest that the stability of this interface is highly dependent on the elastic properties of the solid separator. For example, dendritic suppression is predicted to be enhanced as the electrolyte s shear modulus increases. Inmore » the present study a combination of first-principles calculations, acoustic impulse excitation measurements, and nanoindentation experiments are used to determine the elastic constants and moduli for highconductivity LLZO compositions based on Al and Ta doping. The calculated and measured isotropic shear moduli are in good agreement and fall within the range of 56-61 GPa. These values are an order of magnitude larger than that for Li metal and far exceed the minimum value ( 8.5 GPa) believed to be necessary to suppress dendrite initiation. These data suggest that LLZO exhibits sufficient stiffness to warrant additional development as a solid electrolyte for Li batteries.« less

  11. Electrical and thermal properties of Tb0.3Dy0.7Fe2-x

    NASA Astrophysics Data System (ADS)

    Cook, B. A.; Harringa, J. L.; Hansen, T.

    2000-01-01

    Samples of Tb0.3Dy0.7Fe2-x where x=0.05-0.10 (TERFENOL-D) were characterized for electrical resistivity and thermal diffusivity between room temperature and the Curie temperature, which for this composition is 360 °C. Additionally, the thermal diffusivity of one of the samples was measured to 1000 °C. Measurements were performed on two different orientations of standard, production-grade, grain-oriented TERFENOL-D produced by a Bridgman growth technique at ETREMA Products, Inc. The orientations were parallel and normal to the <112> crystallographic direction. The electrical resistivity and thermal diffusivity both exhibited isotropic behavior over the temperature range studied. The electrical resistivity of all samples increased monotonically from 0.06 mΩ-cm at room temperature to 0.14 mΩ cm at 360 °C, consistent with behavior expected for normal metals. The thermal conductivity was found to decrease with temperature from 135 mW/cm °C at room temperature to 122 mW/cm °C at 360 °C. The thermal diffusivity was found to exhibit a sharp cusp in the vicinity of the Curie temperature, TC, increasing with temperature for T>TC. Application of the Wiedemann-Franz law indicates that over 86% of the heat is carried by electrons.

  12. Enhanced critical currents by silver sheeting of YBa2Cu3O7-δ thin films

    NASA Astrophysics Data System (ADS)

    Kienzle, M.; Albrecht, J.; Warthmann, R.; Kronmüller, H.; Leonhardt, S.; Jooss, Ch.

    2002-08-01

    Magneto-optical investigation of flux penetration into high-temperature superconducting thin films allows the determination of the local critical current density jc by an inversion scheme of Biot-Savart's law. This method is used to examine the influence of silver sheeting on jc in thin films of YBa2Cu3O7-δ (YBCO) quantitatively. It can be found that a feasible silver covering layer on top of a YBCO thin film can enhance the critical current density by up to 50%. Spatially resolved measurements of the magnetic-flux density distribution in partly silver covered YBCO films show the influence of the cover layer on the current pattern in the superconductor. The measured enhancement of the critical current density, that is induced by the silver layer, has its origin in a spatially varying proximity effect between superconductor and silver layer which leads to a strong variation of the flux-line energies on a small length scale. This variation is directly related to an additional pinning force density on the flux lines. A detailed model is developed that can explain the measured enhancement of the critical current density by considering this additional pinning.

  13. Critical current behavior of Ag-coated YBa2Cu3O(7-x) thin films

    NASA Astrophysics Data System (ADS)

    Ono, R. H.; Beall, J. A.; Harvey, T. E.; Reintsema, C. D.; Johansson, M.

    1991-03-01

    The authors studied the behavior of high-quality YBa2Cu3O(7-x) (YBCO) thin films with Ag overlayers. The authors chose to study Ag in detail because of its widespread use as contact metallization and because of their earlier studies of proximity effects in YBCO. The details of transport critical current measurements are presented. It is shown that the Ag coatings can reduce normal state resistance while not degrading the critical current density. The key technological result is that the various thicknesses of Ag that were used did not reduce Jc or Jc(H). Critical current densities in excess of 106 A/sq cm have been achieved at temperatures greater than 76 K. An unusual effect was seen in Jc(H) when the field was oriented perpendicular to the c axis of the film. The Jc at 1 T was higher in samples with 10-nm coatings of Ag than in similar uncoated samples. It was also shown that the composite resistance of Ag-YBCO bilayers can be much lower than the resistance of uncoated YBCO.

  14. Thermodynamics of phase formation in the quantum critical metal Sr3Ru2O7

    PubMed Central

    Rost, A. W.; Grigera, S. A.; Bruin, J. A. N.; Perry, R. S.; Tian, D.; Raghu, S.; Kivelson, Steven Allan; Mackenzie, A. P.

    2011-01-01

    The behavior of matter near zero temperature continuous phase transitions, or “quantum critical points” is a central topic of study in condensed matter physics. In fermionic systems, fundamental questions remain unanswered: the nature of the quantum critical regime is unclear because of the apparent breakdown of the concept of the quasiparticle, a cornerstone of existing theories of strongly interacting metals. Even less is known experimentally about the formation of ordered phases from such a quantum critical “soup.” Here, we report a study of the specific heat across the phase diagram of the model system Sr3Ru2O7, which features an anomalous phase whose transport properties are consistent with those of an electronic nematic. We show that this phase, which exists at low temperatures in a narrow range of magnetic fields, forms directly from a quantum critical state, and contains more entropy than mean-field calculations predict. Our results suggest that this extra entropy is due to remnant degrees of freedom from the highly entropic state above Tc. The associated quantum critical point, which is “concealed” by the nematic phase, separates two Fermi liquids, neither of which has an identifiable spontaneously broken symmetry, but which likely differ in the topology of their Fermi surfaces. PMID:21933961

  15. Thermodynamics of phase formation in the quantum critical metal Sr3Ru2O7.

    PubMed

    Rost, A W; Grigera, S A; Bruin, J A N; Perry, R S; Tian, D; Raghu, S; Kivelson, Steven Allan; Mackenzie, A P

    2011-10-01

    The behavior of matter near zero temperature continuous phase transitions, or "quantum critical points" is a central topic of study in condensed matter physics. In fermionic systems, fundamental questions remain unanswered: the nature of the quantum critical regime is unclear because of the apparent breakdown of the concept of the quasiparticle, a cornerstone of existing theories of strongly interacting metals. Even less is known experimentally about the formation of ordered phases from such a quantum critical "soup." Here, we report a study of the specific heat across the phase diagram of the model system Sr(3)Ru(2)O(7), which features an anomalous phase whose transport properties are consistent with those of an electronic nematic. We show that this phase, which exists at low temperatures in a narrow range of magnetic fields, forms directly from a quantum critical state, and contains more entropy than mean-field calculations predict. Our results suggest that this extra entropy is due to remnant degrees of freedom from the highly entropic state above T(c). The associated quantum critical point, which is "concealed" by the nematic phase, separates two Fermi liquids, neither of which has an identifiable spontaneously broken symmetry, but which likely differ in the topology of their Fermi surfaces.

  16. Optical and scintillation properties of ce-doped (Gd2Y1)Ga2.7Al2.3O12 single crystal grown by Czochralski method

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Wu, Yuntao; Ding, Dongzhou; Li, Huanying; Chen, Xiaofeng; Shi, Jian; Ren, Guohao

    2016-06-01

    Multicomponent garnets, due to their excellent light yield and energy resolution, become one of the most promising scintillators used for homeland security and nuclear non-proliferation applications. This work focuses on the optimization of Ce-doped (Gd,Y)3(Ga,Al)5O12 scintillators using a combination strategy of pre-screening and scale-up. Ce-doped GdxY1-xGayAl5-yO12 (x=1, 2 and y=2, 2.2, 2.5, 2.7, 3) polycrystalline powders were prepared by high-temperature solid state reaction method. The desired garnet phase in all the samples was confirmed using X-ray diffraction measurement. By comparing the radioluminescence intensity, the highest scintillation efficiency was achieved at a component of Gd2Y1Ga2.7Al2.3O12:Ce powders. A (Gd2Y1)Ga2.7Al2.3O12 doped with 1% Ce single crystal with dimensions of Ø35×40 mm was grown by Czochralski method using a <111> oriented seed. Luminescence and scintillation properties were measured. An optical transmittance of 84% was achieved in the concerned wavelength from 500 to 800 nm. Its 5d-4f emission of Ce3+ is at 530 nm. The light yield of a Ce1%: Gd2Y1Ga2.7Al2.3O12 single crystal slab at a size of 5×5×1 mm3 can reach about 65,000±3000 Ph/MeV along with two decay components of 94 and 615 ns under 137Cs source irradiation.

  17. Superconductor to Mott insulator transition in YBa2Cu3O7/LaCaMnO3 heterostructures

    PubMed Central

    Gray, B. A.; Middey, S.; Conti, G.; Gray, A. X.; Kuo, C.-T.; Kaiser, A. M.; Ueda, S.; Kobayashi, K.; Meyers, D.; Kareev, M.; Tung, I. C.; Liu, Jian; Fadley, C. S.; Chakhalian, J.; Freeland, J. W.

    2016-01-01

    The superconductor-to-insulator transition (SIT) induced by means such as external magnetic fields, disorder or spatial confinement is a vivid illustration of a quantum phase transition dramatically affecting the superconducting order parameter. In pursuit of a new realization of the SIT by interfacial charge transfer, we developed extremely thin superlattices composed of high Tc superconductor YBa2Cu3O7 (YBCO) and colossal magnetoresistance ferromagnet La0.67Ca0.33MnO3 (LCMO). By using linearly polarized resonant X-ray absorption spectroscopy and magnetic circular dichroism, combined with hard X-ray photoelectron spectroscopy, we derived a complete picture of the interfacial carrier doping in cuprate and manganite atomic layers, leading to the transition from superconducting to an unusual Mott insulating state emerging with the increase of LCMO layer thickness. In addition, contrary to the common perception that only transition metal ions may respond to the charge transfer process, we found that charge is also actively compensated by rare-earth and alkaline-earth metal ions of the interface. Such deterministic control of Tc by pure electronic doping without any hindering effects of chemical substitution is another promising route to disentangle the role of disorder on the pseudo-gap and charge density wave phases of underdoped cuprates. PMID:27627855

  18. Superconductor to Mott insulator transition in YBa2Cu3O7/LaCaMnO3 heterostructures.

    PubMed

    Gray, B A; Middey, S; Conti, G; Gray, A X; Kuo, C-T; Kaiser, A M; Ueda, S; Kobayashi, K; Meyers, D; Kareev, M; Tung, I C; Liu, Jian; Fadley, C S; Chakhalian, J; Freeland, J W

    2016-01-01

    The superconductor-to-insulator transition (SIT) induced by means such as external magnetic fields, disorder or spatial confinement is a vivid illustration of a quantum phase transition dramatically affecting the superconducting order parameter. In pursuit of a new realization of the SIT by interfacial charge transfer, we developed extremely thin superlattices composed of high Tc superconductor YBa2Cu3O7 (YBCO) and colossal magnetoresistance ferromagnet La0.67Ca0.33MnO3 (LCMO). By using linearly polarized resonant X-ray absorption spectroscopy and magnetic circular dichroism, combined with hard X-ray photoelectron spectroscopy, we derived a complete picture of the interfacial carrier doping in cuprate and manganite atomic layers, leading to the transition from superconducting to an unusual Mott insulating state emerging with the increase of LCMO layer thickness. In addition, contrary to the common perception that only transition metal ions may respond to the charge transfer process, we found that charge is also actively compensated by rare-earth and alkaline-earth metal ions of the interface. Such deterministic control of Tc by pure electronic doping without any hindering effects of chemical substitution is another promising route to disentangle the role of disorder on the pseudo-gap and charge density wave phases of underdoped cuprates. PMID:27627855

  19. Superconductor to Mott insulator transition in YBa2Cu3O7/LaCaMnO3 heterostructures

    DOE PAGES

    Gray, B. A.; Middey, S.; Conti, G.; Gray, A. X.; Kuo, C. -T.; Kaiser, A. M.; Ueda, S.; Kobayashi, K.; Meyers, D.; Kareev, M.; et al

    2016-09-15

    The superconductor-to-insulator transition (SIT) induced by means such as external magnetic fields, disorder or spatial confinement is a vivid illustration of a quantum phase transition dramatically affecting the superconducting order parameter. In this paper, in pursuit of a new realization of the SIT by interfacial charge transfer, we developed extremely thin superlattices composed of high Tc superconductor YBa2Cu3O7 (YBCO) and colossal magnetoresistance ferromagnet La0.67Ca0.33MnO3 (LCMO). By using linearly polarized resonant X-ray absorption spectroscopy and magnetic circular dichroism, combined with hard X-ray photoelectron spectroscopy, we derived a complete picture of the interfacial carrier doping in cuprate and manganite atomic layers, leadingmore » to the transition from superconducting to an unusual Mott insulating state emerging with the increase of LCMO layer thickness. In addition, contrary to the common perception that only transition metal ions may respond to the charge transfer process, we found that charge is also actively compensated by rare-earth and alkaline-earth metal ions of the interface. Finally, such deterministic control of Tc by pure electronic doping without any hindering effects of chemical substitution is another promising route to disentangle the role of disorder on the pseudo-gap and charge density wave phases of underdoped cuprates.« less

  20. Superconductor to Mott insulator transition in YBa2Cu3O7/LaCaMnO3 heterostructures

    NASA Astrophysics Data System (ADS)

    Gray, B. A.; Middey, S.; Conti, G.; Gray, A. X.; Kuo, C.-T.; Kaiser, A. M.; Ueda, S.; Kobayashi, K.; Meyers, D.; Kareev, M.; Tung, I. C.; Liu, Jian; Fadley, C. S.; Chakhalian, J.; Freeland, J. W.

    2016-09-01

    The superconductor-to-insulator transition (SIT) induced by means such as external magnetic fields, disorder or spatial confinement is a vivid illustration of a quantum phase transition dramatically affecting the superconducting order parameter. In pursuit of a new realization of the SIT by interfacial charge transfer, we developed extremely thin superlattices composed of high Tc superconductor YBa2Cu3O7 (YBCO) and colossal magnetoresistance ferromagnet La0.67Ca0.33MnO3 (LCMO). By using linearly polarized resonant X-ray absorption spectroscopy and magnetic circular dichroism, combined with hard X-ray photoelectron spectroscopy, we derived a complete picture of the interfacial carrier doping in cuprate and manganite atomic layers, leading to the transition from superconducting to an unusual Mott insulating state emerging with the increase of LCMO layer thickness. In addition, contrary to the common perception that only transition metal ions may respond to the charge transfer process, we found that charge is also actively compensated by rare-earth and alkaline-earth metal ions of the interface. Such deterministic control of Tc by pure electronic doping without any hindering effects of chemical substitution is another promising route to disentangle the role of disorder on the pseudo-gap and charge density wave phases of underdoped cuprates.

  1. Superconductor to Mott insulator transition in YBa2Cu3O7/LaCaMnO3 heterostructures.

    PubMed

    Gray, B A; Middey, S; Conti, G; Gray, A X; Kuo, C-T; Kaiser, A M; Ueda, S; Kobayashi, K; Meyers, D; Kareev, M; Tung, I C; Liu, Jian; Fadley, C S; Chakhalian, J; Freeland, J W

    2016-01-01

    The superconductor-to-insulator transition (SIT) induced by means such as external magnetic fields, disorder or spatial confinement is a vivid illustration of a quantum phase transition dramatically affecting the superconducting order parameter. In pursuit of a new realization of the SIT by interfacial charge transfer, we developed extremely thin superlattices composed of high Tc superconductor YBa2Cu3O7 (YBCO) and colossal magnetoresistance ferromagnet La0.67Ca0.33MnO3 (LCMO). By using linearly polarized resonant X-ray absorption spectroscopy and magnetic circular dichroism, combined with hard X-ray photoelectron spectroscopy, we derived a complete picture of the interfacial carrier doping in cuprate and manganite atomic layers, leading to the transition from superconducting to an unusual Mott insulating state emerging with the increase of LCMO layer thickness. In addition, contrary to the common perception that only transition metal ions may respond to the charge transfer process, we found that charge is also actively compensated by rare-earth and alkaline-earth metal ions of the interface. Such deterministic control of Tc by pure electronic doping without any hindering effects of chemical substitution is another promising route to disentangle the role of disorder on the pseudo-gap and charge density wave phases of underdoped cuprates.

  2. Cancer mortality in workers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin

    SciTech Connect

    Fingerhut, M.A.; Halperin, W.E.; Marlow, D.A.; Piacitelli, L.A.; Honchar, P.A.; Sweeney, M.H.; Greife, A.L.; Dill, P.A.; Steenland, K.; Suruda, A.J. )

    1991-01-24

    In both animal and epidemiologic studies, exposure to dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, or TCDD) has been associated with an increased risk of cancer. We conducted a retrospective cohort study of mortality among the 5172 workers at 12 plants in the United States that produced chemicals contaminated with TCDD. Occupational exposure was documented by reviewing job descriptions and by measuring TCDD in serum from a sample of 253 workers. Causes of death were taken from death certificates. Mortality from several cancers previously associated with TCDD (stomach, liver, and nasal cancers, Hodgkin's disease, and non-Hodgkin's lymphoma) was not significantly elevated in this cohort. Mortality from soft-tissue sarcoma was increased, but not significantly (4 deaths; standardized mortality ratio (SMR), 338; 95 percent confidence interval, 92 to 865). In the subcohort of 1520 workers with greater than or equal to 1 year of exposure and greater than or equal to 20 years of latency, however, mortality was significantly increased for soft-tissue sarcoma (3 deaths; SMR, 922; 95 percent confidence interval, 190 to 2695) and for cancers of the respiratory system (SMR, 142; 95 percent confidence interval, 103 to 192). Mortality from all cancers combined was slightly but significantly elevated in the overall cohort (SMR, 115; 95 percent confidence interval, 102 to 130) and was higher in the subcohort with greater than or equal to 1 year of exposure and greater than or equal to 20 years of latency (SMR, 146; 95 percent confidence interval, 121 to 176). This study of mortality among workers with occupational exposure to TCDD does not confirm the high relative risks reported for many cancers in previous studies. Conclusions about an increase in the risk of soft-tissue sarcoma are limited by small numbers and misclassification on death certificates.

  3. Field modulated microwave absorption in YBa{sub 2}Cu{sub 3}O{sub 7}/PrBa{sub 2}Cu{sub 3}O{sub 7} multilayers

    SciTech Connect

    Dumas, J.; Thrane, B.P.; Feinberg, D.

    1996-11-01

    The authors describe field modulated microwave absorption measurements on YBa{sub 2}Cu{sub 3}O{sub 7} / PrBa{sub 2}Cu{sub 3}O{sub 7} multilayers with PrBa{sub 2}Cu{sub 3}O{sub 7} thickness in the range 2.5 to 10 nm and with a fixed YBa{sub 2}Cu{sub 3}O{sub 7} thickness of 10 nm. The Fourier spectrum of the reflected microwave power reveals one fundamental frequency which appears at T{sub c} and even harmonics of the modulation field frequency {omega} at lower temperatures. The determination of the irreversibility line near T{sub c} for different values of the PrBa{sub 2}Cu{sub 3}O{sub 7} thickness and inferred from the vanishing of the nonlinear response signal at 2{omega} in the presence of superimposed dc and modulation fields is reported.

  4. 6,7-Dimethoxy-2-{2-[4-(1H-1,2,3-triazol-1-yl)phenyl]ethyl}-1,2,3,4-tetrahydroisoquinolines as superior reversal agents for P-glycoprotein-mediated multidrug resistance.

    PubMed

    Liu, Baomin; Qiu, Qianqian; Zhao, Tianxiao; Jiao, Lei; Li, Yunman; Huang, Wenlong; Qian, Hai

    2015-02-01

    P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) is a major obstacle for successful cancer chemotherapy. Based on our previous study, 17 novel compounds with the 6,7-dimethoxy-2-{2-[4-(1H-1,2,3-triazol-1-yl)phenyl]ethyl}-1,2,3,4-tetrahydroisoquinoline scaffold were designed and synthesized. Among them, 2-[(1-{4-[2-(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)ethyl]phenyl}-1H-1,2,3-triazol-4-yl)methoxy]-N-(p-tolyl)benzamide (compound 7 h) was identified as a potent modulator of P-gp-mediated MDR, with high potency (EC50 =127.5 ± 9.1 nM), low cytotoxicity (TI>784.3), and long duration (>24 h) in reversing doxorubicin (DOX) resistance in K562/A02 cells. Compound 7 h also enhanced the effects of other MDR-related cytotoxic agents (paclitaxel, vinblastine, and daunorubicin), increased the accumulation of DOX and blocked P-gp-mediated rhodamine 123 efflux function in K562/A02 MDR cells. Moreover, 7 h did not have any effect on cytochrome (CYP3A4) activity. These results indicate that 7 h is a relatively safe modulator of P-gp-mediated MDR that has good potential for further development.

  5. 49 CFR 545.7 - Reporting requirements for vehicles listed in § 541.3(b)(2).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 6 2011-10-01 2011-10-01 false Reporting requirements for vehicles listed in § 541.3(b)(2). 545.7 Section 545.7 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR VEHICLE THEFT PREVENTION STANDARD PHASE-IN...

  6. A novel redox reaction between 8-Aza-5,7-dimethyl-2-trifluoromethylchromone and alkyl mercaptoacetates. Facile synthesis of CF3-containing 2-pyridone derivatives.

    PubMed

    Sosnovskikh, Vyacheslav Ya; Barabanov, Mikhail A; Usachev, Boris I

    2004-11-26

    8-Aza-5,7-dimethyl-2-trifluoromethylchromone reacts with alkyl mercaptoacetates in the presence of triethylamine to give pyrido derivatives of 2-oxa-7-thiabicyclo[3.2.1]octane, which undergo the reductive ring opening to alkyl 2-[[3-(4,6-dimethyl-2-oxo-1,2-dihydropyridin-3-yl)-3-oxo-1-(trifluoromethyl)propyl]sulfanyl]acetates. The latter can be also obtained directly from 8-aza-5,7-dimethyl-2-trifluoromethylchromone and behave as the masked alpha,beta-unsaturated ketone, 4,6-dimethyl-3-(4,4,4-trifluorobut-2-enoyl)pyridin-2(1H)-one. This compound was independently synthesized from 3-acetyl-4,6-dimethyl-2-pyridone, and its synthetic potential was studied. A wide variety of 2-pyridone derivatives containing the CF(3) group have been prepared in good to moderate yields.

  7. Synthesis, characterization, and crystal structure of 2-amino-7-methyl-5-oxo-4-phenyl-4,5-dihydropyrano[3,2-c] pyran-3-carbonitrile

    SciTech Connect

    Sharma, S.; Banerjee, B.; Brahmachari, G.; Kant, Rajni; Gupta, V. K.

    2015-12-15

    2-Amino-7-methyl-5-oxo-4-phenyl-4,5-dihydropyrano[3,2-c] pyran-3-carbonitrile, C{sub 16}H{sub 12}N{sub 2}O{sub 3} is synthesized via one-pot multi-component reaction at room temperature using commercially available urea as inexpensive and environmentally benign organo-catalyst. Its structure is determined by single-crystal X-ray diffraction technique The crystals are monoclinic, a = 10.7357(12), b = 8.7774(8), c = 15.0759(16) Å, β = 103.575(11)°, Z = 4, sp. gr. P2{sub 1}/n, R = 0.0551 for 1696 observed reflections. The crystal structure is stabilized by N–H···N, C–H···O, and C–H···π interactions.

  8. All chemical solution deposition of textured YBa2Cu3O7-x/Y0.2Ce0.8O2/La2Zr2O7 multilayer films on biaxially textured NiW tape

    NASA Astrophysics Data System (ADS)

    Chen, Yuanqing; Tang, Xinni; Bian, Weibai; Li, Mengjuan; Jiang, Ping; Zhao, Gaoyang

    2015-07-01

    Biaxially textured La2Zr2O7 (LZO) single buffer layer, Y0.2Ce0.8O2 (YCO) single buffer layer, and YCO/LZO bilayer buffer layer are prepared on NiW tapes using chemical solution deposition technique. All the buffer layers are of good in-plane and out-of-plane texture. The introduction of a YCO cap layer on the LZO buffer layer improves the surface quality of the films. YBa2Cu3O7-x (YBCO) films are then prepared on these buffer layers using our recently developed low-fluorine solution route. Purely c-oriented YBCO films with good in-plane and out-of-plane texture are obtained on the YCO/LZO bilayer buffer layers. The YBCO/YCO/LZO/Ni stack prepared using all chemical solution routes shows a high Tc over 90 K, a sharp transition temperature ΔT = 0.8 K, and a Jc of 0.7 MA cm-2(at 77 K, 0T).

  9. Structure and physical properties of new iron hydrogenophosphates: K2Fe(HP2O7)(H2PO4)2, LiH3Fe2(P2O7)2, and FeH2P2O7.

    PubMed

    Pralong, V; Baies, R; Caignaert, V; Raveau, B

    2009-07-20

    The exploration of the systems Fe-H-P-O, Li-Fe-H-P-O, and K-Fe-H-P-O using soft chemistry methods has allowed three new hydrogenophosphates to be synthesized, whose structures have been determined by ab initio calculations. The structures of two of them--FeH(2)P(2)O(7) and LiH(3)Fe(P(2)O(7))(2)--exhibit close relationships: their 3D framework consists of [FeO(4)](infinity) and [LiFe(2)O(12)](infinity) chains of edge-sharing octahedra, respectively, interconnected through diphosphate groups. These two diphosphates exhibit a paramagnetic to antiferromagnetic transition at low temperatures. The former phase exhibits intrachain ferromagnetic interactions (theta(p) > 0) in competition with the antiferromagnetic interchain ordering, whereas for the second one, the ferromagnetic interactions have disappeared due to the presence of Li in the chains. Differently, the third phosphate, K(2)Fe(HP(2)O(7))(H(2)PO(4))(2), exhibits a chain structure, involving isolated FeO(6) octahedra, and consequently is paramagnetic in the whole temperature range (4-300 K). Among these three phosphates, only the latter exhibits ionic conductivity, which may originate from the proton mobility.

  10. Noncanonical E2 recruitment by the autophagy E1 revealed by Atg7-Atg3 and Atg7-Atg10 structures

    SciTech Connect

    Kaiser, Stephen E; Mao, Kai; Taherbhoy, Asad M; Yu, Shanshan; Olszewski, Jennifer L; Duda, David M; Kurinov, Igor; Deng, Alan; Fenn, Timothy D; Klionsky, Daniel J; Schulman, Brenda A

    2012-11-11

    Core functions of autophagy are mediated by ubiquitin-like protein (UBL) cascades, in which a homodimeric E1 enzyme, Atg7, directs the UBLs Atg8 and Atg12 to their respective E2 enzymes, Atg3 and Atg10. Crystallographic and mutational analyses of yeast (Atg7–Atg3)2 and (Atg7–Atg10)2 complexes reveal noncanonical, multisite E1-E2 recognition in autophagy. Atg7's unique N-terminal domain recruits distinctive elements from the Atg3 and Atg10 'backsides'. This, along with E1 and E2 conformational variability, allows presentation of 'frontside' Atg3 and Atg10 active sites to the catalytic cysteine in the C-terminal domain from the opposite Atg7 protomer in the homodimer. Despite different modes of binding, the data suggest that common principles underlie conjugation in both noncanonical and canonical UBL cascades, whereby flexibly tethered E1 domains recruit E2s through surfaces remote from their active sites to juxtapose the E1 and E2 catalytic cysteines.

  11. A model to evaluate past exposure to 2,3,7,8-TCDD.

    PubMed

    Pinsky, P F; Lorber, M N

    1998-01-01

    Data from several studies suggest that concentrations of dioxins rose in the environment from the 1930s to about the 1960s/70s and have been declining over the last decade or two. The most direct evidence of this trend comes from lake core sediments, which can be used to estimate past atmospheric depositions of dioxins. The primary source of human exposure to dioxins is through the food supply. The pathway relating atmospheric depositions to concentrations in food is quite complex, and accordingly, it is not known to what extent the trend in human exposure mirrors the trend in atmospheric depositions. This paper describes an attempt to statistically reconstruct the pattern of past human exposure to the most toxic dioxin congener, 2,3,7,8-TCDD (abbreviated TCDD), through use of a simple pharmacokinetic (PK) model which included a time-varying TCDD exposure dose. This PK model was fit to TCDD body burden data (i.e., TCDD concentrations in lipid) from five U.S. studies dating from 1972 to 1987 and covering a wide age range. A Bayesian statistical approach was used to fit TCDD exposure; model parameters other than exposure were all previously known or estimated from other data sources. The primary results of the analysis are as follows: (1) use of a time-varying exposure dose provided a far better fit to the TCDD body burden data than did using a dose that was constant over time; this is strong evidence that exposure to TCDD has, in fact, varied during the 20th century, (2) the year of peak TCDD exposure was estimated to be in the late 1960s, which coincides with peaks found in sediment core studies, (3) modeled average exposure doses during these peak years was estimated at 1.4-1.9 pg TCDD/kg-day, and (4) modeled exposure doses of TCDD for the late 1980s of less than 0.10 pg TCDD/kg-day correlated well with recent estimates of exposure doses around 0.17 pg TCDD/kg-day (recent estimates are based on food concentrations combined with food ingestion rates; food is

  12. ESR experiments and spectra simulations in YBa2Cu3O7-x, Y2BaCuO5, and BaCuO2+x

    NASA Astrophysics Data System (ADS)

    de Mesquita, R. N.; Castilho, J. H.; Barberis, G. E.; Rettori, C.; Torriani, I.; de Lima, O. F.; Gama, S.; Jardim, R. F.; Terrile, M. C.; Basso, H.; Nascimento, O. R.

    1989-04-01

    Room-temperature X- and Q-band ESR spectra of the high-Tc superconductor YBa2Cu3O7-x and the semiconductors Y2BaCuO5 and BaCuO2+x are studied experimentally and theoretically by measuring, calculating, and fitting the powder spectra corresponding to an anisotropic Zeeman Hamiltonian for Cu2+ in orthorhombic and tetragonal local symmetries. ESR and x-ray studies in their correspoinding oxygen-deficient stoichiometries, obtained by heat treatment under vacuum, were also done. Our results support those of Bowden et al. and Vier et al. in RBa2Cu3O7-x (R=Y, Eu), indicating that the Cu(1) and Cu(2) atoms in the pure YBa2Cu3O7-x phase are not ESR active and the small resonance observed in these compounds comes from other residual phases. The purest YBa2Cu3O7-xsamples that we were able to prepare still have 0.1-0.5 % mass fraction of other residual copper compounds which are responsible for the observed resonance.

  13. Selective androgen receptor modulators based on a series of 7H-[1,4]oxazino[3,2-g]quinolin-7-ones with improved in vivo activity.

    PubMed

    Long, Yun Oliver; Higuchi, Robert I; Caferro, Thomas R; Lau, Thomas L S; Wu, Min; Cummings, Marquis L; Martinborough, Esther A; Marschke, Keith B; Chang, William Y; López, Francisco J; Karanewsky, Donald S; Zhi, Lin

    2008-05-01

    Modification on a lead series of [1,4]oxazino[3,2-g]quinolin-7-ones at the 2-position led to selective androgen receptor modulators with improved in vivo activity. The most potent analog (-)-33a exhibited full maintenance of levator ani muscle at 3mg/kg and reduced activity on ventral prostate weight in a 2-week orally-dosed and orchidectomized rat maintenance assay.

  14. Face-capping μ3-BO in B6(BO)7-: boron oxide analogue of B6H7- with rhombic 4c-2e bonds.

    PubMed

    Guo, Jin-Chang; Lu, Hai-Gang; Zhai, Hua-Jin; Li, Si-Dian

    2013-11-14

    Using the first-principle approaches, we predict a B6(BO)7(-) cluster with a face-capping μ(3)-BO, which is the boron oxide analogue of closo-B6H7(-) with a face-capping μ(3)-H. Detailed topological analysis of electron density clearly reveals the existence of three rhombic 4c-2e bonds around the B/H apex in both C3v B6(BO)7(-) and C3v B6H7(-), which possesses similar electron densities at their bond and ring critical points. The adaptive natural density partitioning (AdNDP) analysis provides a direct and visual picture of the B-B-B-B/H 4c-2e bonds for the first time. Adiabatic and vertical electron detachment energies of the concerned monoanions are calculated to facilitate their future photoelectron spectroscopy measurements and characterizations. The presence of the B6(BO)7(-) and B6H7(-) clusters extends the BO/H isolobal analogy to the whole μ(n)-BO/H series (n = 1, 2, and 3) and enriches the chemistry of boronyl. PMID:24147988

  15. Transcriptional profiling of rat hypothalamus response to 2,3,7,8-tetrachlorodibenzo-ρ-dioxin.

    PubMed

    Houlahan, Kathleen E; Prokopec, Stephenie D; Moffat, Ivy D; Lindén, Jere; Lensu, Sanna; Okey, Allan B; Pohjanvirta, Raimo; Boutros, Paul C

    2015-02-01

    In some mammals, halogenated aromatic hydrocarbon (HAH) exposure causes wasting syndrome, defined as significant weight loss associated with lethal outcomes. The most potent HAH in causing wasting is 2,3,7,8-tetrachlorodibenzo-ρ-dioxin (TCDD), which exerts its toxic effects through the aryl hydrocarbon receptor (AHR). Since TCDD toxicity is thought to predominantly arise from dysregulation of AHR-transcribed genes, it was hypothesized that wasting syndrome is a result of to TCDD-induced dysregulation of genes involved in regulation of food-intake. As the hypothalamus is the central nervous systems' regulatory center for food-intake and energy balance. Therefore, mRNA abundances in hypothalamic tissue from two rat strains with widely differing sensitivities to TCDD-induced wasting syndrome: TCDD-sensitive Long-Evans rats and TCDD-resistant Han/Wistar rats, 23h after exposure to TCDD (100μg/kg) or corn oil vehicle. TCDD exposure caused minimal transcriptional dysregulation in the hypothalamus, with only 6 genes significantly altered in Long-Evans rats and 15 genes in Han/Wistar rats. Two of the most dysregulated genes were Cyp1a1 and Nqo1, which are induced by TCDD across a wide range of tissues and are considered sensitive markers of TCDD exposure. The minimal response of the hypothalamic transcriptome to a lethal dose of TCDD at an early time-point suggests that the hypothalamus is not the predominant site of initial events leading to hypophagia and associated wasting. TCDD may affect feeding behaviour via events upstream or downstream of the hypothalamus, and further work is required to evaluate this at the level of individual hypothalamic nuclei and subregions.

  16. Percutaneous Absorption of 2,3,7,8-Tetrachlorodibenzo-P-Dioxin (TCDD) From Soil (Journal Article)

    EPA Science Inventory

    Eight dermal absorption (two in vivo; six in vitro) and one intravenous experiment were conducted using 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) either neat (high dose at ~250 µg/cm2 and low dose at 10 ng/cm2) or sorbed on a low organic (LOS) or high organic (HOS) soil at 1 ppm...

  17. TERATOGENIC RESPONSES OF TGFALPHA KNOCKOUT FETUSES TO 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD)

    EPA Science Inventory

    ABBOTT1, B.D., A.R. BUCKALEW1, and P.L. BRYANT2. 1Reproductive Toxicology Division, EPA, RAP, NC; 2Dept. Environ. Sciences & Engineering, UNC, Chapel Hill, NC. Teratogenic responses of TGF knockout fetuses to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).

    TCDD induces cl...

  18. Towards environmentally friendly Na-ion batteries: Moisture and water stability of Na2Ti3O7

    NASA Astrophysics Data System (ADS)

    Zarrabeitia, M.; Castillo-Martínez, E.; López Del Amo, J. M.; Eguía-Barrio, A.; Muñoz-Márquez, M. A.; Rojo, T.; Casas-Cabanas, M.

    2016-08-01

    We report here on the moisture and water stability of the promising Na-ion anode material Na2Ti3O7. Spontaneous Na+/H+ exchange is detected by PXRD after air exposure, forming solid solution compounds of the form Na2-xHxTi3O7 (0 < x < 2). By controlled ion exchange in aqueous solution two mixed compositions are prepared and their composition and structure are characterized with a panel of techniques. Both mixed compositions crystallize in C2/m space group like H2Ti3O7, and therefore Na+/H+ exchange is found to involve a structural transition from AA stacking of [TiO6] layers to AB stacking sequence. The electrochemical behaviour of the mixed compositions vs. Na+/Na is studied as well as that of an electrode of pure Na2Ti3O7 prepared in water media. The water-processed electrode is shown to exhibit a superior cycling stability and therefore the results obtained highlight the potential of Na2Ti3O7 as a green, low cost anode material for NIBs.

  19. Towards environmentally friendly Na-ion batteries: Moisture and water stability of Na2Ti3O7

    NASA Astrophysics Data System (ADS)

    Zarrabeitia, M.; Castillo-Martínez, E.; López Del Amo, J. M.; Eguía-Barrio, A.; Muñoz-Márquez, M. A.; Rojo, T.; Casas-Cabanas, M.

    2016-08-01

    We report here on the moisture and water stability of the promising Na-ion anode material Na2Ti3O7. Spontaneous Na+/H+ exchange is detected by PXRD after air exposure, forming solid solution compounds of the form Na2-xHxTi3O7 (0 < x < 2). By controlled ion exchange in aqueous solution two mixed compositions are prepared and their composition and structure are characterized with a panel of techniques. Both mixed compositions crystallize in C2/m space group like H2Ti3O7, and therefore Na+/H+ exchange is found to involve a structural transition from AA stacking of [TiO6] layers to AB stacking sequence. The electrochemical behaviour of the mixed compositions vs. Na+/Na is studied as well as that of an electrode of pure Na2Ti3O7 prepared in water media. The water-processed electrode is shown to exhibit a superior cycling stability and therefore the results obtained highlight the potential of Na2Ti3O7 as a green, low cost anode material for NIBs.

  20. Golgi-modifying properties of macfarlandin E and the synthesis and evaluation of its 2,7-dioxabicyclo[3.2.1]octan-3-one core

    PubMed Central

    Schnermann, Martin J.; Beaudry, Christopher M.; Egorova, Anastasia V.; Polishchuk, Roman S.; Sütterlin, Christine; Overman, Larry E.

    2010-01-01

    Golgi-modifying properties of the spongian diterpene macfarlandin E (MacE) and a synthetic analog, t-Bu-MacE, containing its 2,7-dioxabicyclo[3.2.1]octan-3-one moiety are reported. Natural product screening efforts identified MacE as inducing a novel morphological change in Golgi structure defined by ribbon fragmentation with maintenance of the resulting Golgi fragments in the pericentriolar region. t-Bu-MacE, which possesses the substituted 2,7-dioxabicyclo[3.2.1]octan-3-one but contains a tert-butyl group in place of the hydroazulene subunit of MacE, was prepared by chemical synthesis. Examination of the Golgi-modifying properties of MacE, t-Bu-MacE, and several related structures revealed that the entire oxygen-rich bridged-bicyclic fragment is required for induction of this unique Golgi organization phenotype. Further characterization of MacE-induced Golgi modification showed that protein secretion is inhibited, with no effect on the actin or microtubule cytoskeleton being observed. The conversion of t-Bu-MacE and a structurally related des-acetoxy congener to substituted pyrroles in the presence of primary amines in protic solvent at ambient temperatures suggests that covalent modification might be involved in the Golgi-altering activity of MacE. PMID:20332207

  1. 40 CFR 721.5262 - 2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[substituted] amino]-1,3,5-triazin-2-yl]amino]-4...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...,7-Naphthalenedisulfonic acid, 5- amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3- -, trisodium salt...-Naphthalenedisulfonic acid, 5- amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3- -, trisodium salt (PMN P-00-0803) is...-naphthalenedisulfonic acid, 5- ethyl]amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3- -, sodium salt (1:3) (PMN......

  2. Oxygen desorption from YBa2Cu3O(7-x) and Bi2CaSr2Cu2O(8 + delta) superconductors

    NASA Technical Reports Server (NTRS)

    Mesarwi, A.; Levenson, L. L.; Ignatiev, A.

    1991-01-01

    Oxygen desorption experiments from YBa2Cu3O(7-x) (YBCO) and Bi2CaSr2Cu2O(8 + delta) (BSCCO) superconductors were carried out using a quadrupole mass spectrometer for monitoring the desorbing species and X-ray photoemission spectroscopy for surface characterization. Molecular oxygen was found to desorb from both superconductors following photoirradiation with ultraviolet/optical radiation and subsequent heating at over 150 C. Both YBCO and BSCCO were found to have similar oxygen desorption rates and similar activation energies. The desorption data as well as the X-ray photoemission data indicate that the oxygen desorption is not intrinsic to the superconductors but rather due to molecular oxygen entrapped in the material.

  3. In vivo formation of N7-guanine DNA adduct by safrole 2',3'-oxide in mice.

    PubMed

    Shen, Li-Ching; Chiang, Su-Yin; Lin, Ming-Huan; Chung, Wen-Sheng; Wu, Kuen-Yuh

    2012-09-18

    Safrole, a naturally occurring product derived from spices and herbs, has been shown to be associated with the development of hepatocellular carcinoma in rodents. Safrole 2',3'-oxide (SFO), an electrophilic metabolite of safrole, was shown to react with DNA bases to form detectable DNA adducts in vitro, but not detected in vivo. Therefore, the objective of this study was to investigate the formation of N7-(3-benzo[1,3]dioxol-5-yl-2-hydroxypropyl)guanine (N7γ-SFO-Gua) resulting from the reaction of SFO with the most nucleophilic site of guanine in vitro and in vivo with a newly developed isotope-dilution high performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) method. N7γ-SFO-Gua and [(15)N(5)]-N7-(3-benzo[1,3]dioxol-5-yl-2-hydroxypropyl)guanine ([(15)N(5)]-N7γ-SFO-Gua) were first synthesized, purified, and characterized. The HPLC-ESI-MS/MS method was developed to measure N7γ-SFO-Gua in calf thymus DNA treated with 60 μmol of SFO for 72 h and in urine samples of mice treated with a single dose of SFO (30 mg/kg body weight, intraperitoneally). In calf thymus DNA, the level of N7γ-SFO-Gua was 2670 adducts per 10(6)nucleotides. In urine of SFO-treated mice, the levels of N7γ-SFO-Gua were 1.02±0.14 ng/mg creatinine (n=4) on day 1, 0.73±0.68 ng/mg creatinine (n=4) on day 2, and below the limit of quantitation on day 3. These results suggest that SFO can cause in vivo formation of N7γ-SFO-Gua, which may then be rapidly depurinated from the DNA backbone and excreted through urine.

  4. Improved synthesis of ceramic superconductors with alkaline earth peroxides - Synthesis and processing of Ba2YCu3O(7-x)

    NASA Technical Reports Server (NTRS)

    Hepp, A. F.; Gaier, J. R.; Philipp, W. H.; Warner, J. D.; Aron, P. R.; Pouch, J. J.

    1988-01-01

    Synthesis processes for the preparation of ceramic conductors Ba2YCu3O(7-x) from BaO2 or BaCO3 in flowing O2 or N2 are described, and the characteristics of the materials produced in these processes are compared. Results of EDAX, XRD, SEM, and dc resistivity analyses demonstrated that superconducting materials made from BaO2 were more homogeneous, denser, and more metallic than materials produced from BaCO3, because of the higher reactivity of BaO2. Potential applications of this processes are discussed.

  5. The bulk modulus and young's modulus of the superconductor Ba sub 2 Cu sub 3 YO sub 7

    SciTech Connect

    Block, S.; Piermarini, G.J.; Munro, R.G.; Wong-Ng, W. )

    1987-07-01

    The isothermal equation of state of the high temperature superconducting ceramic material Ba{sub 2}Cu{sub 3}YO{sub 7} has been determined by measurements in a diamond anvil pressure cell using an energy dispersive x-ray diffraction method. The orthorhombic unit cell lattice parameters (a = 3.8856 {angstrom}, b = 11.6804 {angstrom}, c = 3.8185 {angstrom}) were found to have compressions of (2.0%, 2.3%, 1.1%) respectively over the pressure range from one atmosphere to 10.6 GPa at room temperature. Subsequent equation of state analysis of the approximately linear compression of the volume determined that the isothermal bulk modulus was 196 {plus minus} 17 GPa. Young's modulus was estimated to be 235 {plus minus} 20 GPa assuming that the Poisson's ratio for Ba{sub 2}Cu{sub 3}YO{sub 7} was 0.3 which is typical of many ceramics.

  6. High Chemical Activity of a Perovskite Surface: Reaction of CO with Sr3Ru2O7

    NASA Astrophysics Data System (ADS)

    Stöger, Bernhard; Hieckel, Marcel; Mittendorfer, Florian; Wang, Zhiming; Fobes, David; Peng, Jin; Mao, Zhiqiang; Schmid, Michael; Redinger, Josef; Diebold, Ulrike

    2014-09-01

    Adsorption of CO at the Sr3Ru2O7(001) surface was studied with low-temperature scanning tunneling microscopy (STM) and density functional theory. In situ cleaved single crystals terminate in an almost perfect SrO surface. At 78 K, CO first populates impurities and then adsorbs above the apical surface O with a binding energy Eads=-0.7 eV. Above 100 K, this physisorbed CO replaces the surface O, forming a bent CO2 with the C end bound to the Ru underneath. The resulting metal carboxylate (Ru-COO) can be desorbed by STM manipulation. A low activation (0.2 eV) and high binding (-2.2 eV) energy confirm a strong reaction between CO and regular surface sites of Sr3Ru2O7; likely, this reaction causes the "UHV aging effect" reported for this and other perovskite oxides.

  7. Zn3(OH)2V2O7·2H2O/g-C3N4: A novel composite for efficient photodegradation of methylene blue under visible-light irradiation

    NASA Astrophysics Data System (ADS)

    Wang, Qizhao; Zheng, Longhui; Bai, Yan; Zhao, Jianjun; Wang, Fangping; Zhang, Rong; Huang, Haohao; Su, Bitao

    2015-08-01

    In this work, we used a facile method to prepare a series of Zn3(OH)2V2O7·2H2O/g-C3N4 composites in a 70 °C water bath for 10 h and characterized them by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (DRS), Brunauer-Emmett-Teller (BET), and photoluminescence (PL). Degradation of methylene blue (MB) and phenol were carried out to evaluate the photocatalytic activities of samples under visible light irradiation. Presence of Zn3(OH)2V2O7·2H2O increased surface areas and promoted the charge separation, exerted great influence on the photocatalytic activity and absorption capacity of g-C3N4. In addition, the synergic effect was explained and a possible photocatalytic mechanism was proposed.

  8. Synthesis and biological activity of novel series of 4-methoxy, and 4,9-dimethoxy-5-substituted furo[2,3-g]-1,2,3-benzoxathiazine-7,7-dioxide derivatives

    PubMed Central

    El-Sawy, Eslam R.; Ebaid, Manal S.; Abo-Salem, Heba M.; El-Hallouty, Salwa; Kassem, Emad M.; Mandour, Adel H.

    2013-01-01

    A novel series of 4-methoxy, and 4,9-dimethoxy-5-substituted furo[2,3-g]-1,2,3-benzoxathiazine-7,7-dioxide derivatives 3a,b, 10a–g and 11a–g were prepared in good yields via the reaction of 4-methoxy (1a) and 4,7-dimethoxy-5-acetyl-6-hydroxybenzofurans (1b) and their α,β-unsaturated keto derivatives 6a–g and 7a–g with chlorosulfonyl isocyanate (CSI). On the other hand, N-chlorosulfonyl carbamate derivatives 4a,b, 12a,b and 13a,b were prepared and allowed to react with piperidine to give the corresponding N-piperidinosulfonyl carbamate derivatives 5a,b, 14a,b and 15a,b, respectively. Sixteen new target compounds 3a,b, 10a–g, and 11a–g were tested for their DPPH radical-scavenging, and in vitro antiproliferative activity against A-549, MCF7 and HCT-116 cancer cell lines. Compounds 10a, 11c, 11e, and 11g showed moderate DPPH radical-scavenging activity compared to ascorbic acid at 100 μg/mL. 4,9-Dimethoxy-5-substituted styrylfuro[3,2-g]-1,2,3-benzoxathiazine-7,7-dioxides 11a, 11b, and 11c were found to be highly active against A-549 and HCT-116 cancer cell lines with IC50 values ranging from 0.02 to 0.08 μmol/mL compared to doxorubicin with IC50 = 0.04 and 0.06 μmol/mL, respectively. PMID:25685501

  9. Synthesis, structure and superconducting properties of metastable Y(Ba/2-x/Y/x/)Cu3O(7+delta)

    NASA Astrophysics Data System (ADS)

    Iqbal, Z.; Reidinger, F.; Bose, A.; Cipollini, N.; Taylor, T. J.

    1988-01-01

    The synthesis and characterization of a majority (90-95 percent) phase Y1.5Ba1.5Cu3O(7+delta), referred to for historical reasons as Y 3-3-6, prepared by firing an atomically mixed citrate precursor between 810 and 825 C for 2 hrs, are reported. X-ray and powder diffraction data indicate that the Y 3-3-6 is isostructural with its La analog La1.5Ba1.5Cu3O(7+delta). Electron microprobe and thermogravimetry data yield a unit-cell composition Y(Ba/2-x/Y/x/)Cu3O(7+delta), with x = 0.50 and delta = 0.10-0.15 for the parent compound. Specimens of Y 3-3-6 with x = 0.50 and 0.375, which were annealed in O2 at 1 atm and at above 3 atm, displayed semiconducting behavior. Filamentary superconductivity, detected electrically and magnetically, with transition onsets at 80 and 60 K respectively, is observed in specimens annealed in 3 atm O2 at 520 C.

  10. The interactions of 2,3,7,8-tetrachlorodibenzo-p-dioxin(TCDD) and 6-methyl-1,3,8-trichlorodibenzofuran (MCDF) in TCDD-induced porphyria

    SciTech Connect

    Yao, Cheng Catsby.

    1989-01-01

    Halogenated aryl hydrocarbon(HAH)-induced porphyria is caused by alteration of porphyrin metabolism and results in the accumulation of hepatic and urinary porphyrins. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (75 {mu}/kg) caused significant increases of hepatic porphyrin levels in C57BL/6 male, female and ovariectomized female, and C57BL/10 male mice 3 weeks after treatment. In contrast, 6-methyl-1,3,8-trichlorodibenzofuran (MCDF) was inactive at a dose of 750 {mu}mol/kg. Cotreatment with MCDF (750 {mu}mol/kg) and 2,3,7,8-TCDD (75 {mu}g/kg) resulted in partial antagonism of 2,3,7,8-TCDD-induced porphyrin accumulation in female but not in male mice. In female C57BL/6 mice, 2,3,7,8-TCDD-induced porphyria was accompanied by the induction of hepatic microsomal aryl hydrocarbon hydroxylase (AHH) and ethoxyresorufin O-deethylase (EROD) activities and the inhibition of uroporphyrinogen decarboxylase (UROD) activity. MCDF (750 {mu}mol/kg) did not significantly affect these enzyme activities. In coadministration studies, MCDF partially antagonized 2,3,7,8-TCDD-induced hepatic porphyrin accumulation but did not affect the activities of hepatic AHH, EROD or UROD. These results demonstrate that the induction of the monooxygenase enzyme activities and the inhibition of UROD activity by 2,3,7,8-TCDD and the development of porphyria are not coordinately regulated in C57BL/6 female mice. In cultured chick embryo hepatocytes, 2,3,7,8-TCDD caused a significant increase in porphyrin levels and induced AHH and EROD activities. MCDF and Aroclor 1254 partially antagonized the 2,3,7,8-TCDD induced AHH and EROD activities but not the porphyrin accumulation.

  11. Crystal and electronic structure changes during the charge-discharge process of Na4Co3(PO4)2P2O7

    NASA Astrophysics Data System (ADS)

    Moriwake, Hiroki; Kuwabara, Akihide; Fisher, Craig A. J.; Nose, Masafumi; Nakayama, Hideki; Nakanishi, Shinji; Iba, Hideki; Ikuhara, Yuichi

    2016-09-01

    Sodium-ion batteries offer a potential solution to the problem of limited lithium resources, and the newly developed positive electrode material Na4Co3(PO4)2P2O7 is attracting significant attention due to its high rate, high capacity, and high voltage compared to other sodium-ion battery materials. However, details of its electronic structure and its charge/discharge behavior are still uncertain. Here we report detailed first-principles calculations of the desodiation behavior of Na4Co3(PO4)2P2O7 using the GGA + U formalism of density functional theory. Assuming a stepwise desodiation process, removal of Na down to NaCo3(PO4)2P2O7 is found to be accompanied by oxidation of Co2+ to Co3+. Further removal of Na to give Co3(PO4)2P2O7 requires oxidation of oxygen 2p orbitals in the P2O7 polyhedra instead of Co3+ being oxidized to Co4+. The holes thus formed are expected to be strongly self-trapped, rendering them immobile at room temperature. At the same time, a large volume shrinkage is observed during this last desodiation step, constricting the Na migration channels. These two factors may explain the difficulty encountered experimentally in removing all Na from Na4Co3(PO4)2P2O7.

  12. The Effect of Ag-DOPING on the Critical Current Density of YBa2Cu3O7-δ Superconductors

    NASA Astrophysics Data System (ADS)

    Lue, Juh Tzeng; Kung, J. H.; Yen, H. H.; Chen, Y. C.; Wu, P. T.

    The superconducting state and the transition temperature Tc of the interstitially Ag-doped YBa2 Cu3 O7-δ are not changed even when the Ag concentration is increased up to 20%, whereas the substitutionally doped YBa2 Cu3-x Agx O7-δ system ceases to be superconductive when the contents x of Ag is over 1.2. Magnetic susceptibility measurement indicates that the interstitial Ag-doping yields higher diamagnetic signal and enhances the critical current density by 15 folds. Photoelectron emission and electron spin resonance spectroscopic studies elucidate that the copper ions change from diamagnetic to paramagnetic states at some doping levels.

  13. Synthesis of the high temperature superconductor YBa 2Cu 3O 7-δ by the hydroxide co-precipitation method

    NASA Astrophysics Data System (ADS)

    Schildermans, I.; Van Bael, M.; Knaepen, E.; Yperman, J.; Mullens, J.; Van Poucke, L. C.

    1997-02-01

    A new synthetic route is developed to prepare a hydroxide precursor for the superconductor YBa 2Cu 3O 7-δ. In an inert atmosphere and at low temperature the yttrium, barium and copper hydroxides are co-precipitated by adding the metal perchlorates and sodium hydroxide together. The analysis of the precursor proved the absence of ClO 4- and Na + ions. The thermal treatment (12 h calcinating at 950°C, 36 h sintering at 950°C and 6 h annealing at 400°C) gives a superconductor YBa 2Cu 3O 7-δ with a transition temperature of 90.2 K.

  14. Structural characterization of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}/Y{sub 2}O{sub 3} composite films

    SciTech Connect

    Broussard, P.R.; Wall, M.A.; Talvacchio, J.

    1998-04-01

    Using 4-circle x-ray diffraction and transmission electron microscopy, we have studied the microstructure and in-plane orientation of the phases present in thin film composite mixtures of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} and Y{sub 2}O{sub 3}. We see a high degree of in-plane orientation and have verified a previous prediction for the in-plane order of Y{sub 2}BaCuO{sub 5} on (110) MgO. Transmission electron microscopy shows the composite films to be a mixture of two phases, with YBCO grain sizes of {approx}1{mu}m. We have also compared our observations of the in-plane order to the predictions of a modified near coincidence site lattice model. {copyright} {ital 1998 Materials Research Society.}

  15. Theoretical study of isoelectronic molecules: B6H10, 2-CB5H9, 2,3-C2B4H8, 2,3,4-C3B3H7, and 2,3,4,5-C4B2H6.

    PubMed

    Tian, Shan Xi

    2005-07-28

    Isoelectronic molecules regarding B6H10, 2-CB5H9, 2,3-C2B4H8, 2,3,4-C3B3H7, and 2,3,4,5-C4B2H6 are studied by the density functional B3LYP/6-311G(d,p) method and the electron propagator theory in the partial third-order quasiparticale approximation, as well as the extrapolated calculation with the coupled-cluster CCSD(T) theory. The calculated ionization potentials are in good agreement with the experimental data from photoelectron spectroscopy. Valence structures are characterized with natural orbital bond (NBO) theory, exhibiting the multiple three-center two-electron bonds B-H-B, B-B-B, C-B-B, B-C-B, and C-B-C, and chemical bond rearrangements in the cations. PMID:16834005

  16. Estrogen increases Nrf2 activity through activation of the PI3K pathway in MCF-7 breast cancer cells

    SciTech Connect

    Wu, Juanjuan; Williams, Devin; Walter, Grant A.; Thompson, Winston E.; Sidell, Neil

    2014-11-01

    The actions of the transcription factor Nuclear factor erythroid 2-related factor (Nrf2) in breast cancer have been shown to include both pro-oncogenic and anti-oncogenic activities which is influenced, at least in part, by the hormonal environment. However, direct regulation of Nrf2 by steroid hormones (estrogen and progesterone) has received only scant attention. Nrf2 is known to be regulated by its cytosolic binding protein, Kelch-like ECH-associated protein 1 (Keap1), and by a Keap1-independent mechanism involving a series of phosphorylation steps mediated by phosphatidylinositol 3-kinase (PI3K) and glycogen synthase kinase 3 beta (GSK3β). Here, we report that estrogen (E2) increases Nrf2 activity in MCF7 breast cancer cells through activation of the PI3K/GSK3β pathway. Utilizing antioxidant response element (ARE)-containing luciferase reporter constructs as read-outs for Nrf2 activity, our data indicated that E2 increased ARE activity >14-fold and enhanced the action of the Nrf2 activators, tertiary butylhydroquinone (tBHQ) and sulforaphane (Sul) 4 to 9 fold compared with cells treated with tBHQ or Sul as single agents. This activity was shown to be an estrogen receptor-mediated phenomenon and was antagonized by progesterone. In addition to its action on the reporter constructs, mRNA and protein levels of heme oxygenase 1, an endogenous target gene of Nrf2, was markedly upregulated by E2 both alone and in combination with tBHQ. Importantly, E2-induced Nrf2 activation was completely suppressed by the PI3K inhibitors LY294002 and Wortmannin while the GSK3β inhibitor CT99021 upregulated Nrf2 activity. Confirmation that E2 was, at least partly, acting through the PI3K/GSK3β pathway was indicated by our finding that E2 increased the phosphorylation status of both GSK3β and Akt, a well-characterized downstream target of PI3K. Together, these results demonstrate a novel mechanism by which E2 can regulate Nrf2 activity in estrogen receptor-positive breast cancer

  17. Structural and optical characterizations of Ca2Al2SiO7:Ce3+, Mn2+ nanoparticles produced via a hybrid route

    NASA Astrophysics Data System (ADS)

    Teixeira, V. C.; Montes, P. J. R.; Valerio, M. E. G.

    2014-07-01

    Pure, Ce3+ doped and Ce3+ and Mn2+ co-doped Ca2Al2SiO7 ceramic powders were prepared by two different methodologies which are the proteic sol-gel process and a new hybrid route combining the proteic sol-gel with solid state reaction processes. The second one is an eco-friendly method because it uses natural raw materials in replacement of the metal alkoxides used in the traditional sol-gel routes. X-ray diffraction showed that Ca2Al2SiO7 crystalline phase was obtained for both preparations. Differential thermal analysis indicated that the exothermic event around 850 °C, for sample produced by proteic sol-gel method, and around 927 °C, for ceramics prepared by hybrid synthesis, can be associated to crystallization of Ca2Al2SiO7. Transmission electron microscope indicates that regular and spherical nanoparticles were obtained with average sizes of about 12 nm. The Scherrer’s method was used to determine the average crystallite sizes and it was shown that nanometric crystallites were obtained of about 74 nm for samples produced via hybrid route. For all the single phase samples, the crystallite sizes are about the same and that agrees with TEM results. Diffuse optical reflectance measurements were used to estimate the Ca2Al2SiO7 optical band gap and the obtained value is about 6 eV, photoluminescence (PL) spectra presented typical emissions of Ce3+ and Mn2+ ions. Upon excitation at 352 nm the emission spectra showed a broad band centered at 415 nm due to the Ce3+ 4f1 → 5d1 typical transition. This emission is resonant with Mn2+ excitation and it transfers energy to Mn ions generating a second broad emission band centered at 620 nm due to the Mn2+. The PL results were used to obtain, as a fist approach, the Ce3+ energy levels diagram and, using the Tanabe-Sugano diagrams, the transitions due to the Mn2+ were calculated. X-ray excited optical luminescence measurements showed the same emission spectra as the PL emission spectra. Luminescence lifetime decay

  18. The effect of heat treatment on the corrosion resistance of 440C stainless steel in 20% HNO3 + 2.5% Na2Cr2O7 solution

    NASA Astrophysics Data System (ADS)

    Savas, Terence P.; Wang, Allen Yi-Lan; Earthman, James C.

    2003-04-01

    The effect of heat treatment on the corrosion resistance of 440C stainless steel was investigated in a 20% HNO3 + 2.5% Na2Cr2O7 solution using electrochemical noise (ECN) measurements, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) examinations. The noise resistance ( Rn), which has been found to be inversely related to the localized corrosion rate, was measured to be 5.7E + 08 Ω-cm2, 4.2E + 08 Ω-cm2, and 3.7E + 04 Ω-cm2 for the oil-quenched, air-quenched, and vacuum furnace cooled (VFC) samples, respectively, after 1200 s exposures. The Rn for all heat treat conditions stabilized within a range of 1.0E + 07 Ω-cm2 to 3.2E + 08 Ω-cm2 after 2 h exposures. The EIS response showed a polarization resistance ( R p) on the order of 6.6E + 04 Ω-cm2, 5.3E + 04 Ω-cm2, and 1.1E + 04 Ω-cm2 for the oil-quenched, air-quenched, and VFC samples, respectively, after 2 h exposures. The EIS data are in good agreement with ECN data and indicate that after longer exposures, general corrosion mechanisms dominate and the corrosion rates are comparable. SEM examinations of specimens subjected to 1200 s exposures revealed that severity of pitting and intergranular corrosion damage was consistent with trends in the Rn data. Specifically, the electrochemical noise data as well as SEM examinations of specimens revealed a higher localized corrosion resistance of the hardened specimens during the early stages of passivation. This greater resistance to localized corrosion can be attributed to an increased stability of the natural passive film resulting from a higher concentration of chromium atoms in solution for the martensite phase.

  19. Large area superconducting YBa 2Cu 3O 7-x films grown by single target ion beam sputtering

    NASA Astrophysics Data System (ADS)

    Gauzzi, Andrea; Lucía, Maria L.; Kellett, Bruce J.; James, Jonathan H.; Pavuna, Davor

    1991-10-01

    We have demonstrated, by using a simple single YBa 2Cu 3O 7- x target ion beam system that, with a sufficiently low power ion beam, preferential sputtering is avoided and high-quality YBa 2Cu 3O 7- x films are deposited over areas larger than ≈ 30 cm 2 in a reproducible way. As-deposited films on <100>SrTiO 3 are 50-100 nmthick, c-oriented and show the following reproducible electrical properties (within the given variations): Tc0 =90±0.5 K, transitions widths less than 1 K, j inc(77 K)=1.0-1.2× 10 6 A cm -2, ϱ(300 K)=300±50μΩ cm, ϱ(300 K)/ ϱ(100 K)=2.9±0.1. The extrapolated residual resistivity ϱ res(O K) is between 0 and 5% of ϱ(300 K).

  20. The concentration and distribution of 2,3,7,8-dibenzo-p-dioxins/-furans in chickens

    NASA Technical Reports Server (NTRS)

    Ferrario, J.; Byrne, C.

    2000-01-01

    The concentrations of the 2,3,7,8-Cl substituted dibenzo-p-dioxins/-furans (PCDDs/PCDFs) were determined in the edible tissues of whole chicken fryers and compared with the values found in their abdominal fat. The values are presented both on a whole weight basis and on a lipid adjusted basis for each tissue. While there is a marked difference in the concentration of the 2,3,7,8-dibenzo-p-dioxins in the edible tissues expressed on a whole weight basis, the lipid-adjusted concentrations of the individual dioxins were not statistically different in the various tissues. This validates the use of lipid adjusted concentrations of 2,3,7,8-PCDDs/PCDFs in abdominal fat for the determination of the presence of these compounds in different tissues.

  1. Electrochemical formation of polypyrrole films on YBa sub 2 Cu sub 3 O sub 7- x. Technical report

    SciTech Connect

    Osteryoung, J.G.; Magee, L.J.; Carlin, R.T.

    1988-10-01

    Aqueous electrochemical processes at the surface of the high-temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 7-x}, including deposition of silver and magnesium, have been reported. This superconductor dissolves spontaneously under acidic conditions, and barium dissolves and oxide films form during anodization in neutral and basic electrolytes. An additional complication for electrodeposition of metals onto YBa{sub 2}Cu{sub 3}O{sub 7-x} is the competing reduction of the substrate. We report here the electrodeposition of polypyrrole from acetonitrile (MeCN) onto YBa{sub 2}Cu{sub 3}O{sub 7-x}. Since polypyrrole is formed by oxidation of pyrrole, the substrate is not reduced at the potentials employed. For comparison, deposition of AG from MeCN is also discussed.

  2. Anisotropy of oxygen tracer diffusion in YBa sub 2 Cu sub 3 O sub 7-. delta. single crystals

    SciTech Connect

    Rothman, S.J.; Routbort, J.L.; Liu, J.-Z.; Downey, J.W.; Thompson, L.J.; Fang, Y.; Shi, D.; Baker, J.E.; Rice, J.P.; Ginsberg, D.M.; Illinois Univ., Urbana, IL . Materials Research Lab.)

    1989-09-01

    The crystal structure of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} strongly suggests that the diffusion of oxygen in this material will be highly anisotropic, with diffusion in the ab plane being much faster than diffusion parallel to the c axis, and this has been assumed in most analyses of diffusion in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}. The present data confirm this hypothesis; the diffusion coefficient in the ab plane is several orders of magnitude greater than the diffusion coefficient along the c axis. Some interesting artifacts of the measurement, due to this strong anisotropy, are also revealed. Oxygen exchange in polycrystalline samples of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} is discussed in terms of these results. 15 refs., 9 figs.

  3. Development of 3D full-core ERANOS-2.2/MCNPX-2.7.0 models and neutronic analysis of the BFS-2 zero-power facility

    SciTech Connect

    Girardin, G.; Alonso, M.; Mikityuk, K.

    2012-07-01

    The present paper is addressing the development and validation against experimental data of 3D full-core models of the BFS-2 zero-power fast-reactor using both the deterministic system code ERANOS-2.2 and the stochastic code MCNPX-2.7.0. The model configuration of BFS considered for analysis is the BFS-62-3A benchmark. To extend the - deterministic/stochastic - code-to-code comparison, neutronic parameters, i.e. reactivity, neutron spectrum and reaction rates, were also simulated at the cell level with the Monte Carlo code SERPENT-1.1.7 with two modern data libraries, ENDF-B/VII and JEFF-3.1.1. The BFS-2 critical zero-power facility at the Inst. of Physics and Power Engineering (IPPE) was designed for simulations of the core and shielding of sodium-cooled, fast reactors, for neutron data validation and comparison with experimental results. At the BFS-2 facility, the BFS-62-3A critical benchmark experiment was set-up as a mock-up of the BN-600 reactor, with hybrid MOX fuel and stainless steel reflectors. A UO{sub 2} blanket and a large non-homogeneous stainless-steel reflector surround the core. The lattice is hexagonal of pitch 5.1 cm and metallic dowels are used to keep in central position cylindrical rods made of different types of material (fissile, fertile, blanket, plenum, shielding and absorber). A typical subassembly is formed in piling up various pellets of about 1 cm in height and 4.6 cm in diameter, conferring large heterogeneity in the axial direction. The full-core model development was a complex task due to the large number of subassemblies and the axial subassembly heterogeneity. In ERANOS-2.2, it was necessary to homogenize axially per region the pellets used to form the subassembly. The self-shielded macroscopic cross-sections were calculated using the cell code ECCO in association with JEFF-3.1 and ENDF/B-VI.8 data libraries. The core calculations were performed with broad cross-sections data in 33 neutron energy groups with the solver AVNM in the

  4. Characterization and humidity sensing properties of the sensor based on Na2Ti3O7 nanotubes.

    PubMed

    Zhang, Yupeng; Wu, Jian; Zhang, Ying; Guo, Wenbin; Ruan, Shenping

    2014-06-01

    Na2Ti3O7 nanotubes was synthesized by a hydrothermal method, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Then the material was coated on Al2O3 ceramic substrate to fabricate humidity sensors using Ag-Pd as interdigitated electrodes. The sensor shows high humidity sensitivity and quick response-recovery time. The impedance changes about five orders of magnitude within humidity range from 11% to 95% relative humidity (RH). At the frequency of 100 Hz, the response time is 2 s and recovery time is 4 s, and the maximum hysteresis is less than 3% RH. Moreover, complex impedance property at different RH was investigated to study sensing mechanism. The results indicate the potential applications of Na2Ti3O7 nanotubes for fabricating high-performance humidity sensors.

  5. Instability investigation of In0.7Ga0.3As quantum-well MOSFETs with Al2O3 and Al2O3/HfO2

    NASA Astrophysics Data System (ADS)

    Kwon, Hyuk-Min; Kim, Do-Kywn; Lim, Sung-Kyu; Hwang, Hae-Chul; Son, Seung Woo; Park, Jung Ho; Park, Won-Sang; Kim, Jin Su; Shin, Chan-Soo; Park, Won-Kyu; Lee, Jung Hee; Kim, Taewoo; Kim, Dae-Hyun

    2016-07-01

    We present an instability investigation of In0.7Ga0.3As quantum-well (QW) metal-oxide-semiconductor field-effect-transistors (MOSFETs) on InP substrate with Al2O3 and Al2O3/HfO2 gate stacks. The device with bi-layer Al2O3/HfO2 gate stack exhibits larger shift in threshold-voltage (ΔVT) under a constant-voltage-stress condition (CVS), than one with single Al2O3 gate stack. At cryogenic temperature, the device with bi-layer Al2O3/HfO2 gate stack also induces worse hysteresis behavior than one with single Al2O3 gate stack. These are mainly attributed to more traps inside the HfO2 material, yielding a charge build-up inside the HfO2 gate dielectric. This strongly calls for a follow-up process to minimize those traps within the high-k dielectric layer and eventually to improve the reliability of InGaAs MOSFETs with HfO2-based high-k gate dielectric.

  6. Selective interlayer ferromagnetic coupling between the Cu spins in YBa2Cu3O7−x grown on top of La0.7Ca0.3MnO3

    PubMed Central

    Huang, S. W.; Wray, L. Andrew; Jeng, Horng-Tay; Tra, V. T.; Lee, J. M.; Langner, M. C.; Chen, J. M.; Roy, S.; Chu, Y. H.; Schoenlein, R. W.; Chuang, Y.-D.; Lin, J.-Y.

    2015-01-01

    Studies to date on ferromagnet/d-wave superconductor heterostructures focus mainly on the effects at or near the interfaces while the response of bulk properties to heterostructuring is overlooked. Here we use resonant soft x-ray scattering spectroscopy to reveal a novel c-axis ferromagnetic coupling between the in-plane Cu spins in YBa2Cu3O7−x (YBCO) superconductor when it is grown on top of ferromagnetic La0.7Ca0.3MnO3 (LCMO) manganite layer. This coupling, present in both normal and superconducting states of YBCO, is sensitive to the interfacial termination such that it is only observed in bilayers with MnO2 but not with La0.7Ca0.3O interfacial termination. Such contrasting behaviors, we propose, are due to distinct energetic of CuO chain and CuO2 plane at the La0.7Ca0.3O and MnO2 terminated interfaces respectively, therefore influencing the transfer of spin-polarized electrons from manganite to cuprate differently. Our findings suggest that the superconducting/ferromagnetic bilayers with proper interfacial engineering can be good candidates for searching the theorized Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state in cuprates and studying the competing quantum orders in highly correlated electron systems. PMID:26573394

  7. Selective interlayer ferromagnetic coupling between the Cu spins in YBa2Cu3O7–x grown on top of La0.7Ca0.3MnO3

    DOE PAGES

    Huang, S. W.; Wray, L. Andrew; Jeng, Horng -Tay; Tra, V. T.; Lee, J. M.; Langner, M. C.; Chen, J. M.; Roy, S.; Chu, Y. H.; Schoenlein, R. W.; et al

    2015-11-17

    Studies to date on ferromagnet/d-wave superconductor heterostructures focus mainly on the effects at or near the interfaces while the response of bulk properties to heterostructuring is overlooked. Here we use resonant soft x-ray scattering spectroscopy to reveal a novel c-axis ferromagnetic coupling between the in-plane Cu spins in YBa2Cu3O7–x (YBCO) superconductor when it is grown on top of ferromagnetic La0.7Ca0.3MnO3 (LCMO) manganite layer. This coupling, present in both normal and superconducting states of YBCO, is sensitive to the interfacial termination such that it is only observed in bilayers with MnO2 but not with La0.7Ca0.3O interfacial termination. Thus, such contrasting behaviors,more » we propose, are due to distinct energetic of CuO chain and CuO2 plane at the La0.7Ca0.3O and MnO2 terminated interfaces respectively, therefore influencing the transfer of spin-polarized electrons from manganite to cuprate differently. Our findings suggest that the superconducting/ferromagnetic bilayers with proper interfacial engineering can be good candidates for searching the theorized Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state in cuprates and studying the competing quantum orders in highly correlated electron systems.« less

  8. Phase stability of cubic pyrochlore rare earth tantalate pinning additives in YBa2Cu3O7- superconductor

    SciTech Connect

    Wee, Sung Hun; Cantoni, Claudia; Zuev, Yuri L; Specht, Eliot D; Goyal, Amit

    2012-01-01

    Phase stability of cubic-pyrochlore-structured RE3TaO7 (RTO, where RE = rare earth elements) pinning additives in YBa2Cu3O7- (YBCO) superconductor and the pinning properties influenced by RTO addition into YBCO films were investigated. RTO completely reacts with YBCO and is converted to cubic-double-perovskite-structured Ba2RETaO6 (BRETO), a more thermodynamically stable tantalate phase within YBCO. In RTO-doped YBCO films, BRETO self-assembled nanocolumnns align along the c-axis of the film and play a major role in the improvement of flux pinning and Jc performance over wide magnetic field and angular ranges.

  9. A new method for measuring low resistivity contacts between silver and YBa2Cu3O(7-x) superconductor

    NASA Technical Reports Server (NTRS)

    Hsi, Chi-Shiung; Haertling, Gene H.; Sherrill, Max D.

    1991-01-01

    Several methods of measuring contact resistivity between silver electrodes and YBa2Cu3O(7-x) superconductors were investigated; including the two-point, the three point, and the lap-joint methods. The lap-joint method was found to yield the most consistent and reliable results and is proposed as a new technique for this measurement. Painting, embedding, and melting methods were used to apply the electrodes to the superconductor. Silver electrodes produced good ohmic contacts to YBa2Cu3O(7-x) superconductors with contact resistivities as low as 1.9 x 10 to the -9th ohm sq cm.

  10. 5,6,7-trisubstituted 4-aminopyrido[2,3-d]pyrimidines as novel inhibitors of adenosine kinase.

    PubMed

    Perner, Richard J; Gu, Yu-Gui; Lee, Chih-Hung; Bayburt, Erol K; McKie, Jeffery; Alexander, Karen M; Kohlhaas, Kathy L; Wismer, Carol T; Mikusa, Joe; Jarvis, Michael F; Kowaluk, Elizabeth A; Bhagwat, Shripad S

    2003-11-20

    The synthesis and structure-activity relationship of a series of 5,6,7-trisubstituted 4-aminopyrido[2,3-d]pyrimidines as novel nonnucleoside adenosine kinase inhibitors is described. A variety of alkyl, aryl, and heteroaryl substituents were found to be tolerated at the C5, C6, and C7 positions of the pyridopyrimidine core. These studies have led to the identification of analogues that are potent inhibitors of adenosine kinase with in vivo analgesic activity.

  11. Synthesis and biological activity of 7H-benzo[4,5]indolo[2,3-b]-quinoxaline derivatives.

    PubMed

    Shibinskaya, Marina O; Karpenko, Alexander S; Lyakhov, Sergey A; Andronati, Sergey A; Zholobak, Nadezhda M; Spivak, Nikolay Ya; Samochina, Natalia A; Shafran, Lev M; Zubritsky, Mykhail Ju; Galat, Valerij F

    2011-02-01

    New 7-(2-aminoethyl)-7H-benzo[4,5]indolo[2,3-b]quinoxalines (13-20) were synthesized with high yields starting from 3H-benzo[e]indole-1,2-dione. These compounds were screened for the cytotoxicity, anti-viral activity, interferon inducing ability and DNA affinity compared with the corresponding 6-(2-aminoethyl)-6H-indolo[2,3-b]quinoxaline derivatives (1-12). It was shown, that compounds 13-20 bind to DNA stronger (lg Кa=6.23-6.87) than compounds 1-12 (lg Кa=5.57-5.89). Anti-viral activity is significantly reduced with annulations of benzene ring in Indoloquinoxaline moiety 13-20.

  12. Hybrid artificial pinning centers of elongated-nanorods and segmented-nanorods in YBa2Cu3O7 films

    NASA Astrophysics Data System (ADS)

    Horide, Tomoya; Sakamoto, Nobuhiro; Ichinose, Ataru; Otsubo, Koji; Kitamura, Takanori; Matsumoto, Kaname

    2016-10-01

    To control the anisotropy of critical current density (J c), hybrid artificial pinning centers (APCs) of elongated-nanorods and segmented-nanorods were incorporated into YBa2Cu3O7 films. The elongated-nanorods and segmented-nanorods were formed by fabricating multilayer films using YBa2Cu3O7+BaSnO3 targets with a different BaSnO3 content. According to the elastic calculation, the BaSnO3-free YBa2Cu3O7 regions between BaSnO3 segmented-nanorods were highly strained, resulting in their alignment along the c-axis. Pinning of the vortex kinks and straight vortices by the nanorod ends improved J c in a wide range around B//ab. The angular dependence of J c systematically varied with the multilayer structure of layer thickness and BSO content. J c depended on the layer thickness even with keeping the constant average BSO content, showing that the BaSnO3 distribution, as well as the average BaSnO3 content, affected the J c. The hybrid pinning effect of elongated-nanorods and nanorod ends improved the J c anisotropy although the effect was not so large in the present films. The control of strain and interface is expected to lead to further improvement of J c.

  13. StarD7 Knockdown Modulates ABCG2 Expression, Cell Migration, Proliferation, and Differentiation of Human Choriocarcinoma JEG-3 Cells

    PubMed Central

    Flores-Martín, Jésica; Rena, Viviana; Márquez, Sebastián; Panzetta-Dutari, Graciela M.; Genti-Raimondi, Susana

    2012-01-01

    Background StAR-related lipid transfer domain containing 7 (StarD7) is a member of the START-domain protein family whose function still remains unclear. Our data from an explorative microarray assay performed with mRNAs from StarD7 siRNA-transfected JEG-3 cells indicated that ABCG2 (ATP-binding cassette sub-family G member 2) was one of the most abundantly downregulated mRNAs. Methodology/Principal Findings Here, we have confirmed that knocking down StarD7 mRNA lead to a decrease in the xenobiotic/lipid transporter ABCG2 at both the mRNA and protein levels (−26.4% and −41%, p<0.05, at 48 h of culture, respectively). Also a concomitant reduction in phospholipid synthesis, bromodeoxyuridine (BrdU) uptake and 3H-thymidine incorporation was detected. Wound healing and transwell assays revealed that JEG-3 cell migration was significantly diminished (p<0.05). Conversely, biochemical differentiation markers such as human chorionic gonadotrophin β-subunit (βhCG) protein synthesis and secretion as well as βhCG and syncytin-1 mRNAs were increased approximately 2-fold. In addition, desmoplakin immunostaining suggested that there was a reduction of intercellular desmosomes between adjacent JEG-3 cells after knocking down StarD7. Conclusions/Significance Altogether these findings provide evidence for a role of StarD7 in cell physiology indicating that StarD7 modulates ABCG2 multidrug transporter level, cell migration, proliferation, and biochemical and morphological differentiation marker expression in a human trophoblast cell model. PMID:22952907

  14. Photolithographically patterened thin-film multilayer devices of YBa sub 2 Cu sub 3 O sub 7-x

    SciTech Connect

    Kingston, J.J.; Wellstood, F.C.; Quan, D.; Clarke, J.

    1990-09-01

    We have fabricated thin-film YBa{sub 2}Cu{sub 3}O{sub 7-x}-SrTiO{sub 3}-YBa{sub 2}Cu{sub 3}O{sub 7-x} multilayer interconnect structures in which each in situ laser-deposited film is independently patterned by photolithography. In particular, we have constructed the two key components necessary for a superconducting multilayer interconnect technology, crossovers and window contacts. As a further demonstration of the technology, we have fabricated a thin-film flux transformer, suitable for use with a Superconducting QUantum Interference Device (SQUID), that includes a ten-turn input coil with 6{mu}m linewidth. Transport measurements showed that the critical temperature was 87K and the critical current was 135 {mu}A at 82K. 7 refs., 6 figs.

  15. X-ray Mapping in Heterocyclic Design: XIV. Tricyclic Heterocycles Based on 2-Oxo-1,2,5,6,7,8-Hexahydroquinoline-3-Carbonitrile

    SciTech Connect

    Mazina, O.S.; Rybakov, V.B.; Chernyshev, V.V.; Babaev, E.V.; Aslanov, L.A.

    2004-11-01

    The structures of four compounds are studied using single-crystal X-ray diffraction: 1-[2-(4-chlorophenyl)-2-oxoethyl]-2-oxo-1,2,5,6,7,8-hexahydroquinoline -3-carbonitrile [a = 4.908(4) A, b = 11.644(10) A, c = 13.587(2) A, {beta} = 94.31(5) deg., Z = 2, space group P2{sub 1}]; 2-[2-(4-chlorophenyl)-2-oxoethoxy]-5,6,7,8-tetrahydroquinoline -3-carbonitrile [a = 7.6142(8) A, b = 14.778(2) A, c = 14.132(2) A, {beta} = 100.38(1) deg., Z = 4, space group P2{sub 1}/c]; 4-(aminocarbonyl)-2-(chlorophenyl)-6,7,8,9-tetrahydro[1.3]oxazolo[3,2-a] quinolin-3-ium perchlorate [a = 5.589(7) A, b = 24.724(15) A, c = 13.727(5) A, {beta} = 97.66(9) deg., Z = 4, space group P2{sub 1}/n]; and (3-amino-5,6,7,8-tetrahydrofuro[2,3-b]quinolin-2-yl)-(4-chlorophenyl) methanone [a = 7.150(2) A, b = 7.4288(10) A, c = 15.314(3) A, {alpha} = 98.030(10) deg., {beta} = 99.21(2) deg., {gamma} = 105.34(2) deg., Z = 2, space group P1-bar]. The structures are solved by direct methods and refined by the full-matrix least-squares procedure in the anisotropic approximation to R = 0.0728, 0.0439, 0.1228, and 0.0541, respectively. The structure of 1-(4-chlorophenyl)-4-piperidin-1-yl-8,9-dihydro-7H-pyrrolo[3.2.1-ij] quinoline-5-carboxamide [a = 23.9895(9) A, b = 5.1557(3) A, c = 17.0959(9) A, {beta} = 106.43 deg., Z = 4, space group P{sub 1}/c] is investigated by X-ray powder diffraction. This structure is solved using the grid search procedure and refined by the Rietveld method to R{sub wp} = 0.0773, R{sub exp} = 0.0540, R{sub p} = 0.0585, R{sub b} = 0.1107, and {chi}{sup 2} = 1.78.

  16. Interleukin-7 optimizes FOXP3+CD4+ regulatory T cells reactivity to interleukin-2 by modulating CD25 expression.

    PubMed

    Simonetta, Federico; Gestermann, Nicolas; Bloquet, Stéphane; Bourgeois, Christine

    2014-01-01

    The vast majority of Foxp3 regulatory T cells (Treg) exhibits constitutive expression of CD25 (IL-2Rα), which allows the constitution of the high affinity IL-2Rαβγ receptor, ensuring efficient IL-2 binding by Treg. Maintenance of CD25 expression at Treg surface depends on both cell intrinsic factors and environmental stimuli such as IL-2 itself. Whether other factors can participate to maintenance of CD25 expression in vivo is at present unknown. In the present work we demonstrated that IL-7, a gamma-chain cytokine exerting a crucial role in T cell development and homeostasis, is able and necessary to sustain the expression of high levels of CD25 at Treg surface. We demonstrated that, during in vitro cultures performed in the absence of IL-2, IL-7 is able to sustain CD25 expression at Treg surface through a transcriptional mechanism. By studying mice in which IL-7 signaling is either genetically impaired or increased and by employing adoptive transfer murine models, we demonstrated that IL-7 is necessary for sustained expression of CD25 at Treg surface in vivo. To ascertain the biological impact of IL-7 mediated modulation of CD25 expression, we demonstrated that IL-7 modulation of CD25 expression at Treg surface affected their ability to efficiently bind IL-2 and transduce IL-2 signaling. Finally, we demonstrated that IL-7 dependent modulation of CD25 associated with potentiated IL-2 induced expansion of Treg in vivo. Collectively, our results identify IL-7 as a necessary factor contributing to sustained CD25 expression at Treg surface in vivo thereby affecting their ability to efficiently react to IL-2. PMID:25485946

  17. Plasmon-enhanced UV and blue upconverted emissions of Tm3+-doped 12CaO·7Al2O3 nanocrystals by attaching Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhu, Hancheng; Liu, Yuxue; Zhao, Dongxing; Zhang, Meng; Yang, Jian; Yan, Duanting; Liu, Chunguang; Xu, Changshan; Layfield, Carter; Ma, Li; Wang, Xiaojun

    2016-09-01

    Tm3+-doped 12CaO·7Al2O3 (C12A7) nanocrystals with the grain size of 360 nm have been fabricated by chemical co-precipitation method. Up-converted emissions at 367, 457, 476, 648, and 682 nm, corresponding to the 1D23H6, 1D23F4, 1G4 → 3H6, 1G4 → 3F4, and 3F33H6 transitions, respectively, are observed under 808 nm excitation. Plasmon-enhanced ultraviolet (UV) and blue upconverted emissions of Tm3+-doped C12A7 nanocrystals have been achieved by attaching Ag nanoparticles onto the surface of nanocrystals. The enhancement of the upconverted emissions is highly wavelength-dependent. The emission intensities of the sample with Ag+ concentration of 5.0 × 10-3 mol/L at 367 and 476 nm are enhanced about 10 and 3 times, respectively, relative to the sample without Ag attachment. The enhancement mechanism can be ascribed to surface plasmon resonance due to the highly localized electric field and the increased radiative decay rate around Ag nanoparticles. Our results suggest that Tm3+-doped C12A7 nanocrystals by attaching Ag nanoparticles might be a potential material for upconversion, compact and tunable short-wavelength lasers.

  18. White light emission and energy transfer in Dy{sup 3+}/Eu{sup 3+} co-doped BaLa{sub 2}WO{sub 7} phosphors

    SciTech Connect

    Deng, Yaomin; Yi, Shuangping Huang, Jun; Xian, Jieqiang; Zhao, Weiren

    2014-09-15

    Highlights: • BaLa{sub 2}WO{sub 7}:Dy{sup 3+}, Eu{sup 3+} phosphors were synthesized by solid-state reaction. • Eu{sup 3+} compensated the red emission component of the BaLa{sub 2}WO{sub 7}:Dy{sup 3+} phosphor. • The observed emission lifetimes indicates the energy transfer from Dy{sup 3+} to Eu{sup 3+}. • BaLa{sub 2}WO{sub 7}:Dy{sup 3+}, Eu{sup 3+} are potential phosphors used in n-UV pumped white LEDs. - Abstract: Tunable full color emissive BaLa{sub 1.75−x}WO{sub 7}:0.25Dy{sup 3+}, xEu{sup 3+} phosphors which peaked at 484 nm (blue), 572 nm (yellow), 593 nm (orange), and 617 nm (red) were synthesized by the traditional solid-state reaction method. The as-synthesized phosphors were characterized by X-ray power diffraction, diffused reflectance spectra, photoluminescence decay curves, photoluminescence excitation and emission spectra. The photoluminescence excitation spectra range from 200 to 500 nm, including an O{sup 2−}⟶W{sup 6+} charge transfer band and several 4f–4f transition peaks of Dy{sup 3+} and Eu{sup 3+}. Co-doping with Eu{sup 3+} compensated the red emission component of the BaLa{sub 2}WO{sub 7}:Dy{sup 3+} phosphor. Furthermore, the energy transfer from Dy{sup 3+} to Eu{sup 3+} was confirmed based on the luminescence spectra and decay curves. The intense white light emissions are suggestive exploration for the potential phosphor for optical materials applications used in the ultraviolet excited white light emitting diodes.

  19. The dopamine D3/D2 receptor agonist 7-OH-DPAT induces cognitive impairment in the marmoset.

    PubMed

    Smith, A G; Neill, J C; Costall, B

    1999-06-01

    Previous work has shown that dopaminergic systems are involved in cognitive function in the common marmoset. The present study investigated the role of dopamine D3 receptors in cognitive performance in the marmoset. The effects of the putative dopamine D3 receptor agonist, 7-OH-DPAT, on performance of a same-day reversal visual object discrimination task were assessed using a miniature Wisconsin General Test Apparatus (WGTA). Within the same test session marmosets acquired a two-choice object discrimination initial task and a reversal task to criterion. 7-OH-DPAT (6-10 microg/kg) significantly impaired reversal task performance only, without affecting acquisition of the initial task. A higher dose of 25 microg/kg 7-OH-DPAT impaired initial task acquisition as well as reversal task acquisition, possibly as a consequence of a nonspecific influence on motor function. The dopamine D2 receptor antagonist (-)sulpiride (5-10 microg/kg) and the alpha2-receptor antagonist yohimbine (50 microg/kg) failed to attenuate the effects of 7-OH-DPAT (6 microg/kg) in this task. In contrast, the dopamine D2/D3 receptor antagonist raclopride (50 microg/kg) significantly attenuated the 7-OH-DPAT-induced impairment of reversal task performance. These results suggest that activation of dopamine D3 receptors produces a selective impairment of aspects of cognitive function in the marmoset.

  20. Neutron irradiation damage effect on superconducting and normal state properties of the YBa 2Cu 3O 7 system

    NASA Astrophysics Data System (ADS)

    Przysłupski, P.; Wiśniewski, A.; Koleśnik, S.; Dobrowolski, W.; Pajączkowska, A.; Pytel, K.; Pytel, B.

    1988-06-01

    Effect of irradiation by fast neutrons on superconducting and normal state properties of the YBa 2Cu 3O 7 samples is presented. Transport measurements showed a degradation of all superconducting parameters, especially the transport critical current density. Critical current densities obtained from magnetization data exhibited a substantial increase / about 15 times at 77 K and H = 10 kOe/ after the irradiation with the fluence in the range 2.4·10 17 ÷ 8.7 · 10 17 n/cm 2. Such an anomalous bahavior is explained in terms of neutron created defects at intergrain regions and improved intragrain pinning.

  1. Structure-activity relationships of 6-(2,6-dichlorophenyl)-8-methyl-2-(phenylamino)pyrido[2,3-d]pyrimidin-7-ones: toward selective Abl inhibitors

    PubMed Central

    Antczak, Christophe; Veach, Darren R.; Ramirez, Christina N.; Minchenko, Maria A.; Shum, David; Calder, Paul A.; Frattini, Mark G.; Clarkson, Bayard; Djaballah, Hakim

    2013-01-01

    We report the design, synthesis and structure-activity relationship (SAR) of a series of novel pyrido[2,3-d]pyrimidin-7-one compounds as potent Abl kinase inhibitors. We evaluate their specificity profile against a panel of human recombinant kinases, as well as their biological profile toward a panel of well characterized cancer cell lines. Our study reveals that substitutions in the -3 and -4 positions of the phenylamino moiety lead to improved potency and improved selectivity both in target-based and cell based assays. Altogether, our results provide an insight into the SAR of pyrido[2,3-d]pyrimidin-7-ones for the development of drug candidates with improved potency and selectivity for the targeted treatment of CML. PMID:19889540

  2. Comparison of Ba sub 2 YCu sub 3 O sub 7 minus. delta. films on NdGaO sub 3 and LaAlO sub 3

    SciTech Connect

    Phillips, J.M.; Siegal, M.P.; Perry, C.L.; Marshall, J.H. )

    1991-03-01

    This paper studies the properties of 100 nm films of Ba{sub 2}YCu{sub 3}O{sub 7{minus}{delta}} (BYCO) grown on LaAlO{sub 3}(100) and NdGaO{sub 3}(100) by co- evaporation of Cy, Y, and BaF{sub 2} followed by a two-stage anneal ex situ. The authors find that the structural properties of the films on both substrates are optimized when the maximum temperature of the anneal is 900{degrees} C, while the superconducting properties are slightly better if the maximum temperature does not exceed 875{degrees} C. Films on LaAlO{sub 3} can tolerate a longer time at the maximum annealing temperature than can films on NdGaP{sub 3}. The authors postulate that this is due to a reaction between Ga in the NdGaO{sub 3} and at least one of the constituents of the BYCO film (probably Y).

  3. Background considerations for the 2H(7Be,3H)6Be experimental data II: Three-body continuum

    NASA Astrophysics Data System (ADS)

    Chae, K. Y.; Guimarães, V.

    2015-11-01

    The present article reports second background considerations for the experimentally obtained 2H(7Be,3H)6Be differential cross sections. The one-neutron transfer reaction was measured in inverse kinematics by using radioactive 7Be ( t 1/2 = 53.2 days) beams at the Holifield Radioactive Ion Beam Facility of the Oak Ridge National Laboratory in 2004 in order to search for the resonances in the unbound 6Be nucleus. Resonances in this nucleus would affect the 3He(3He,2 p)4He reaction rate of the proton-proton chain occurring in stars such as our sun. The result shows, however, that the direct transfer to 6Be resonances is not particularly strong compared to other reaction channels that can produce tritons in the exit channels. The goals of the present work is to better understand the cross section data from transfer reaction measurements by adopting background considerations using the three-body continuum.

  4. Reduced microwave losses of YBa2Cu3O7-δ thin films on electro-optic LiNbO3 crystals

    NASA Astrophysics Data System (ADS)

    Fàbrega, L.; Rubí, R.; Fontcuberta, J.; Sánchez, F.; Ferrater, C.; García-Cuenca, M. V.; Varela, M.; Collado, C.; Mateu, J.; Menendez, O.; O'Callaghan, J. M.

    2002-11-01

    We report on the growth of epitaxial YBa2Cu3O7 thin films on X-cut LiNbO3 single crystals. The use of double CeO2/YSZ buffer layers allows a single in-plane orientation of YBa2Cu3O7, and results in superior superconducting properties. In particular, surface resistance Rs values of 1.4 mΩ have been measured at 8 GHz and 65 K. The attainment of such low values of Rs constitutes a key step toward the incorporation of high Tc materials as electrodes in photonic and acoustic devices.

  5. Crystal structure, spectroscopic investigations and quantum chemical calculation studies of (3aR,6S,7aR)-7a-bromo-6-methyl-2-[(4-methylphenyl)sulfonyl]-1,2,3,6,7,7a-hexahydro-3a,6-epoxyisoindole: A combined experimental and theoretical studies

    NASA Astrophysics Data System (ADS)

    Alaşalvar, Can; Demircan, Aydın; Koşar, Başak; Pekacar, Ali İhsan; Büyükgüngör, Orhan

    2016-11-01

    The crystal structure and spectroscopic properties of (3aR,6S,7aR)-7a-bromo-6-methyl-2-[(4-methylphenyl)sulfonyl]-1,2,3,6,7,7a-hexahydro-3a,6-epoxyisoindole were determined by X-ray diffraction, IR and 13CNMR and 1H NMR spectroscopy techniques. We investigate molecular and crystal structure of the new sulfonamide, which was derived from an environmental friendly cyclization reaction in water. This work allow to the development of a stereo-selective tandem allylamine isomerization/Diels Alder cyclo-addition sequence led to rapid assembly of complex nitrogen containing heterocycles. The molecular geometry from X-ray determination, vibrational frequencies and NMR shifts values of the title compound in the ground state have been calculated by using CAM-B3LYP and B3LYP methods with 6-311++G(d,p) basis sets. The calculated results show that the optimized geometry can well regenerate the crystal structure and theoretical vibrational frequencies and chemical shift data are in good agreement with experimental data. Besides, it is examined nonlinear optic properties, molecular electrostatic potential map and HOMO-LUMO orbitals of the molecule.

  6. Universal Heat Transport in YBa_2Cu_3O_7

    NASA Astrophysics Data System (ADS)

    Taillefer, Louis; Lussier, Benoit; Gagnon, Robert; Behnia, Kamran; Aubin, Hervé

    1997-03-01

    The thermal conductivity κ(T) of YBa_2Cu_3O_6.9 was measured along the a-axis of untwinned single crystals at very low temperatures (0.05 - 1 K). The magnitude of κ in these high-quality crystals is such that it significantly exceeds the maximum possible phonon contribution, thereby revealing unambiguously a dominant quasiparticle conduction at the lowest temperatures. The existence of uncondensed quasiparticles in clean samples at T=T_c/1000 is compelling evidence for an unconventional gap structure with nodes. Moreover, this quasiparticle contribution is essentially unaffected by the addition of up to 3% Zn impurities (which decreases the low-temperature electronic mean free path by a factor of up to 30). This remarkable insensitivity to impurity scattering is a direct confirmation of the universality of transport coefficients predicted for a superconductor with a gap that vanishes along a line of nodes(Patrick A. Lee, Phys. Rev. Lett. 71), 1887 (1993).^,2. Our results are compared with the recent calculations of Graf et al.(M.J. Graf, et al.), Phys. Rev. B 53, 15147 (1996). for a d_x^2-y^2 pairing state, and an excellent quantitative agreement is found for the universal T arrow 0 limit of κ/T.

  7. 3D-QSAR Study of 7,8-Dialkyl-1,3-diaminopyrrolo-[3,2-f] Quinazolines with Anticancer Activity as DHFR Inhibitors

    NASA Astrophysics Data System (ADS)

    Chen, Jin-can; Chen, Lan-mei; Liao, Si-yan; Qian, Li; Zheng, Kang-cheng

    2009-06-01

    A three-dimensional quantitative structure-activity relationship (3D-QSAR) study of a series of 7,8-dialkyl-1,3-diaminopyrrolo-[3,2-f] quinazolines with anticancer activity as dihydrofolate reductase (DHFR) inhibitors was carried out by using the comparative molecular field analysis (CoMFA), on the basis of our reported 2D-QSAR of these compounds. The established 3D-QSAR model has good quality of statistics and good prediction ability; the non cross-validation correlation coefficient and the cross-validation value of this model are 0.993 and 0.619, respectively, the F value is 193.4, and the standard deviation SD is 0.208. This model indicates that the steric field factor plays a much more important role than the electrostatic one, in satisfying agreement with the published 2D-QSAR model. However, the 3D-QSAR model offers visual images of the steric field and the electrostatic field. The 3D-QSAR study further suggests the following: to improve the activity, the substituent R' should be selected to be a group with an adaptive bulk like Et or i-Pr, and the substituent R should be selected to be a larger alkyl. In particular, based on our present 3D-QSAR as well as the published 2D-QSAR, the experimentally-proposed hydrophobic binding mechanism on the receptor-binding site of the DHFR can be further explained in theory. Therefore, the QSAR studies help to further understand the “hydrophobic binding" action mechanism of this kind of compounds, and to direct the molecular design of new drugs with higher activity.

  8. Repeated dose toxicity and relative potency of 1,2,3,4,6,7-hexachloronaphthalene (PCN 66) 1,2,3,5,6,7-hexachloronaphthalene (PCN 67) compared to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for induction of CYP1A1, CYP1A2 and thymic atrophy in female Harlan Sprague-Dawley rats.

    PubMed

    Hooth, Michelle J; Nyska, Abraham; Fomby, Laurene M; Vasconcelos, Daphne Y; Vallant, Molly; DeVito, Michael J; Walker, Nigel J

    2012-11-15

    In this study we assessed the relative toxicity and potency of the chlorinated naphthalenes 1,2,3,4,6,7-hexachloronaphthalene (PCN 66) and 1,2,3,5,6,7-hexachloronaphthalene (PCN 67) relative to that of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Chemicals were administered in corn oil:acetone (99:1) by gavage to female Harlan Sprague-Dawley rats at dosages of 0 (vehicle), 500, 1500, 5000, 50,000 and 500,000 ng/kg (PCN 66 and PCN 67) and 1, 3, 10, 100, and 300 ng/kg (TCDD) for 2 weeks. Histopathologic changes were observed in the thymus, liver and lung of TCDD treated animals and in the liver and thymus of PCN treated animals. Significant increases in CYP1A1 and CYP1A2 associated enzyme activity were observed in all animals exposed to TCDD, PCN 66 and PCN 67. Dose response modeling of CYP1A1, CYP1A2 and thymic atrophy gave ranges of estimated relative potencies, as compared to TCDD, of 0.0015-0.0072, for PCN 66 and 0.00029-0.00067 for PCN 67. Given that PCN 66 and PCN 67 exposure resulted in biochemical and histopathologic changes similar to that seen with TCDD, this suggests that they should be included in the WHO toxic equivalency factor (TEF) scheme, although the estimated relative potencies indicate that these hexachlorinated naphthalenes should not contribute greatly to the overall human body burden of dioxin-like activity.

  9. Electric field tuning of non-volatile three-state magnetoelectric memory in FeCo-NiFe2O4/Pb(Mg1/3Nb2/3)0.7Ti0.3O3 heterostructures

    NASA Astrophysics Data System (ADS)

    Jiang, Changjun; Zhang, Chao; Dong, Chunhui; Guo, Dangwei; Xue, Desheng

    2015-03-01

    We demonstrate electric field impulse-induced reversible tristable magnetization switching in FeCo-NiFe2O4/Pb(Mg1/3Nb2/3)0.7Ti0.3O3 (PMN-PT) heterostructures at room temperature. The magnetic properties of the FeCo-NiFe2O4 film can be changed reversibly by the strain-mediated magnetoelectric coupling effect. Three piezostrain-mediated reversible and stable electric resistance states were obtained in the FeCo-NiFe2O4 film when different electric field impulses were applied, including large positive and negative fields and an impulse that was smaller than the electric coercive field. Consequently, reversible electric field impulse tuning of the tristable resistance state, which is related to the different magnetization switching properties of the materials, was realized. These results provide a promising approach for low loss multistate magnetoelectric memory devices for information storage applications.

  10. Discovery of 3-(5-chloro-2-furoyl)-3,7-diazabicyclo[3.3.0]octane (TC-6683, AZD1446), a novel highly selective α4β2 nicotinic acetylcholine receptor agonist for the treatment of cognitive disorders.

    PubMed

    Mazurov, Anatoly A; Miao, Lan; Bhatti, Balwinder S; Strachan, Jon-Paul; Akireddy, Srinivasa; Murthy, Srinivasa; Kombo, David; Xiao, Yun-de; Hammond, Philip; Zhang, Jenny; Hauser, Terry A; Jordan, Kristen G; Miller, Craig H; Speake, Jason D; Gatto, Gregory J; Yohannes, Daniel

    2012-11-01

    Diversification of essential nicotinic cholinergic pharmacophoric elements, i.e., cationic center and hydrogen bond acceptor, resulted in the discovery of novel potent α4β2 nAChR selective agonists comprising a series of N-acyldiazabicycles. Core characteristics of the series are an exocyclic carbonyl moiety as a hydrogen bond acceptor and endocyclic secondary amino group. These features are positioned at optimal distance and with optimal relative spatial orientation to provide near optimal interactions with the receptor. A novel potent and highly selective α4β2 nAChR agonist 3-(5-chloro-2-furoyl)-3,7-diazabicyclo[3.3.0]octane (56, TC-6683, AZD1446) with favorable pharmaceutical properties and in vivo efficacy in animal models has been identified as a potential treatment for cognitive deficits associated with psychiatric or neurological conditions and is currently being progressed to phase 2 clinical trials as a treatment for Alzheimer's disease.

  11. Effect of particle size on the flux pinning properties of YBa2Cu3O7–δ thin films containing fine Y2O3 nanoprecipitates

    NASA Astrophysics Data System (ADS)

    Yamasaki, H.

    2016-06-01

    The magnetic-field angle dependence of the critical current density, J c(H, θ), was measured at various temperatures in co-evaporated YBa2Cu3O7–δ (YBCO) thin films. The YBCO films showed volcano-shaped J c(θ) peaks around H//ab, and J c(θ) peaks around H//c were not observed. Film A, deposited at a lower temperature than the commercial standard film B, showed lower J c values at high temperatures (T ≥ 60 K) compared with film B, although film A showed higher J c at T = 20 K. Plan-view transmission electron microscope observations revealed that films A and B contained a high density of fine Y2O3 nanoprecipitates. The modes in the distribution of their cross-sectional areas are 10–20 nm2 in film A and 20–30 nm2 in film B. Because of the smaller particle size, film A showed lower J c at high temperatures owing to the smaller elementary pinning force, f p, but showed higher J c at 20 K where the temperature-dependent coherence length ξ ab (T) was short (∼2 nm) and comparable with the radius of Y2O3 nanoparticles. Film A showed anisotropic scaling behavior at T = 70–80 K, and the T dependence of J c followed ∼(1 ‑ T/T c) m (1 + T/T c)2 (m ≈ 2.5), which was expected from a simple flux-pinning model.

  12. Discovery of New Iron Oxide Fe7O9 and its Solid Solution, (Mg,Fe2+)3Fe3+4O9

    NASA Astrophysics Data System (ADS)

    Sinmyo, R.; Bykova, E.; Ovsyannikov, S. V.; McCammon, C. A.; Kupenko, I.; Ismailova, L.; Dubrovinsky, L. S.

    2015-12-01

    Iron oxides are fundamentally important compounds for Earth science. Particularly, the stability and properties of iron oxides are essential information to understand the structure and chemistry of the mantle. Here we report new high-pressure polymorphs of iron oxide Fe7O9 (Fe3+/Fe2+ = 4/3) and its Fe2+-Mg solid solution (Mg,Fe2+)3Fe3+4O9 that can be recovered at ambient conditions. We synthesized single crystals of the both compounds at about 24-26 GPa using a multi-anvil press. Single crystal X-ray diffraction (XRD) studies showed that the crystal structures of both Fe7O9 and (Mg,Fe2+)3Fe3+4O9 have monoclinic C2/m space groups, that differ from any other known lattices of iron oxides. Mössbauer spectra are in agreement with the crystal structure refined from single crystal XRD. This newly found Fe7O9 polymorph suggests that iron oxides may have more variable mixed valence state under high-pressure condition than previously thought. Based on analogy with Fe2+1+nFe3+2O4+n group, a Fe2+3±nFe3+4O9±n group might be also stable at certain high pressures and temperatures and oxygen fugacity.

  13. COMPARATIVE SENSITIVITY OF DIFFERENT LIFE-STAGES OF MEDAKA AND SALMONID FISHES TO 2,3,7,8-TCDD

    EPA Science Inventory

    The early life stages of fish are known to be more sensitive than the adults to the toxicological effects of 2,3,7,8-tetrachlorodibenzo(p)dioxin (TCDD). Embryo larval stages of medake, for example, experience 50% lethality when TCDD residues in the eggs are 1396 pg/g. By contrast...

  14. Spectrophotometric Determination of the Hole Concentration in the Superconductor YBa2Cu3O(sub 7-x)

    ERIC Educational Resources Information Center

    Hoppe, Jack I.; Malati, Mounir A.

    2005-01-01

    An experimental study of ceramic superconductors namely YBa2Cu3O(sub 7-x), which illustrates the use of spectrophotometry, based on the electronic spectra of complexes of Fe(II), Fe(III) and Cu(II) to better understand the stoichiometry of YBCO is described. The results from this experiment are in good agreement with those obtained by the…

  15. Fine Mutational Analysis of 2B8 and 3H7 Tag Epitopes with Corresponding Specific Monoclonal Antibodies.

    PubMed

    Kim, Tae-Lim; Cho, Man-Ho; Sangsawang, Kanidta; Bhoo, Seong Hee

    2016-06-30

    Bacteriophytochromes are phytochrome-like light-sensing photoreceptors that use biliverdin as a chromophore. To study the biochemical properties of the Deinococcus radiodurans bacteriophytochrome (DrBphP) protein, two anti-DrBphP mouse monoclonal antibodies (2B8 and 3H7) were generated. Their specific epitopes were identified in our previous report. We present here fine epitope mapping of these two antibodies by using truncation and substitution of original epitope sequences in order to identify minimized epitope peptides. The previously reported original epitope sequences for 2B8 and 3H7 were truncated from both sides. Our analysis showed that the minimal peptide sequence lengths for 2B8 and 3H7 antibodies were nine amino acids (RDPLPFFPP) and six amino acids (PGEIEE), respectively. We further characterized these peptides in order to investigate their reactivity after single deletion and single substitution of the original peptides. We found that single-substituted 2B8 epitope (RDPLPAFPP) and dual-substituted 3H7 epitope (PGEIAD) showed significantly increased reactivity. These two antibodies with high reactivity for the short modified peptide sequences are valueble for developing new peptide tags for protein research. PMID:27137090

  16. Non-classical heteroacenes: synthesis and properties of anthra[2,3-c:6,7-c']dithiophene derivatives.

    PubMed

    Djukic, Brandon; Perepichka, Dmitrii F

    2011-12-21

    A new class of linear heteroacenes, anthra[2,3-c:6,7-c']dithiophenes, containing non-classical (non-Kekulé) thiophene in a 22-electron π-conjugated system have been prepared by electrochemical reduction. The electronic properties have been studied by DFT calculations and spectroelectrochemistry, supporting the formation of a triplet electronic structure. PMID:22042513

  17. Fine Mutational Analysis of 2B8 and 3H7 Tag Epitopes with Corresponding Specific Monoclonal Antibodies

    PubMed Central

    Kim, Tae-Lim; Cho, Man-Ho; Sangsawang, Kanidta; Bhoo, Seong Hee

    2016-01-01

    Bacteriophytochromes are phytochrome-like light-sensing photoreceptors that use biliverdin as a chromophore. To study the biochemical properties of the Deinococcus radiodurans bacteriophytochrome (DrBphP) protein, two anti-DrBphP mouse monoclonal antibodies (2B8 and 3H7) were generated. Their specific epitopes were identified in our previous report. We present here fine epitope mapping of these two antibodies by using truncation and substitution of original epitope sequences in order to identify minimized epitope peptides. The previously reported original epitope sequences for 2B8 and 3H7 were truncated from both sides. Our analysis showed that the minimal peptide sequence lengths for 2B8 and 3H7 antibodies were nine amino acids (RDPLPFFPP) and six amino acids (PGEIEE), respectively. We further characterized these peptides in order to investigate their reactivity after single deletion and single substitution of the original peptides. We found that single-substituted 2B8 epitope (RDPLPAFPP) and dual-substituted 3H7 epitope (PGEIAD) showed significantly increased reactivity. These two antibodies with high reactivity for the short modified peptide sequences are valueble for developing new peptide tags for protein research. PMID:27137090

  18. SORPTION OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN TO SOILS FROM WATER/METHANOL MIXTURES

    EPA Science Inventory

    Sorption of 14C-labeled 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to soils from water/methanol mixtures has been evaluated by batch shake testing. Uncontaminated soils from Times Beach, MO, were used in these experiments and ranged in fraction organic carbon (U...

  19. THE CONCENTRATION AND DISTRIBUTION OF 2,3,7,8-DIBENZO-P-DIOXINS / - FURANS IN CHICKENS

    EPA Science Inventory

    The concentrations of 2,3,7,8-Cl substituted dibenzo-p-dioxins/-furans (PCDDs/PCDFs) were determined in the edible tissues of whole chicken fryers and compared with the values found in their abdominal fat. The values are presented both on a whole weight basis and on a lipid-adju...

  20. 40 CFR 721.5288 - Chromate(2-), [3-hydroxy-4-[(2-hydroxy-1-naphthenyl)azo]-7-nitro-1-substituted][N-[7-hydroxy-8...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...] -1-substituted]-, salt (generic). 721.5288 Section 721.5288 Protection of Environment ENVIRONMENTAL...-substituted]-, salt (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as chromate(2-), -7- nitro-1-substituted] -1-substituted]-,...

  1. Topochemical fluorination of Sr3(M(0.5)Ru(0.5))2O7 (M = Ti, Mn, Fe), n = 2, Ruddlesden-Popper phases.

    PubMed

    Romero, Fabio Denis; Bingham, Paul A; Forder, Susan D; Hayward, Michael A

    2013-03-18

    Reaction of the appropriate Sr3(M(0.5)Ru(0.5))2O7 (M = Ti, Mn, Fe), n = 2, Ruddlesden-Popper oxide with CuF2 under flowing oxygen results in formation of the oxide-fluoride phases Sr3(Ti(0.5)Ru(0.5))2O7F2, Sr3(Mn(0.5)Ru(0.5))2O7F2, and Sr3(Fe(0.5)Ru(0.5))2O(5.5)F(3.5) via a topochemical anion insertion/substitution process. Analysis indicates the titanium and manganese phases have Ti(4+), Ru(6+) and Mn(4+), Ru(6+) oxidation state combinations, respectively, while Mössbauer spectra indicate an Fe(3+), Ru(5.5+) combination for the iron phase. Thus, it can be seen that the soft fluorination conditions employed lead to formation of highly oxidized Ru(6+) centers in all three oxide-fluoride phases, while oxidation states of the other transition metal M cations remain unchanged. Fluorination of Sr3(Ti(0.5)Ru(0.5))2O7 to Sr3(Ti(0.5)Ru(0.5))2O7F2 leads to suppression of magnetic order as the fluorinated material approaches metallic behavior. In contrast, fluorination of Sr3(Mn(0.5)Ru(0.5))2O7 and Sr3(Fe(0.5)Ru(0.5))2O7 lifts the magnetic frustration present in the oxide phases, resulting in observation of long-range antiferromagnetic order at low temperature in Sr3(Mn(0.5)Ru(0.5))2O7F2 and Sr3(Fe(0.5)Ru(0.5))2O(5.5)F(3.5). The influence of the topochemical fluorination on the magnetic behavior of the Sr3(M(0.5)Ru(0.5))2O(x)F(y) phases is discussed on the basis of changes to the ruthenium oxidation state and structural distortions.

  2. In-situ deposition and processing of YBa2Cu3O(7-x) films and multilayers for optoelectronic devices

    NASA Astrophysics Data System (ADS)

    Villegier, J. C.; Moriceau, H.; Boucher, H.; di Cioccio, L.; Chicault, R.

    1991-03-01

    In situ direct deposition at about 700 C of thin YBa2Cu3O(7-x) superconductive films and multilayers has been done by three techniques using stoichiometric YBa2Cu3O(7-x) sintered targets. Excimer laser ablation in a dc magnetron system with hollow and planar targets leads to 0.5-, 1.2-, and 2.5-in diameter uniformly superconductive layers under static conditions. High critical current densities associated with low resistivity and good epitaxial behavior are achieved on top of MgO, SrTiO3, LaAlO3, and YSZ single-crystal wafers. High-quality c-oriented films are routinely obtained by means of a dc magnetron on large sapphire substrates covered by a YSZ RF sputtered buffer layer. The infrared properties of such films have been checked at 1.15-micron wavelength. In order to achieve active devices, small YBa2Cu3O7-YSZ-Ag tunnel junctions and arrays have been successfully patterned in the superconductor/insulator/normal-metal trilayers using SNOP (selective niobium overlap process).

  3. R2O3 (R = La, Y) modified erbium activated germanate glasses for mid-infrared 2.7 μm laser materials

    PubMed Central

    Cai, Muzhi; Zhou, Beier; Wang, Fengchao; Wei, Tao; Tian, Ying; Zhou, Jiajia; Xu, Shiqing; Zhang, Junjie

    2015-01-01

    Er3+ activated germanate glasses modified by La2O3 and Y2O3 with good thermal stability were prepared. 2.7 μm fluorescence was observed and corresponding radiative properties were investigated. A detailed discussion of J–O parameters has been carried out based on absorption spectra and Judd–Ofelt theory. The peak emission cross sections of La2O3 and Y2O3 modified germanate glass are (14.3 ± 0.10) × 10−21 cm2 and (15.4 ± 0.10) × 10−21 cm2, respectively. Non-radiative relaxation rate constants and energy transfer coefficients of 4I11/2 and 4I13/2 levels have been obtained and discussed to understand the 2.7 μm fluorescence behavior. Moreover, the energy transfer processes of 4I11/2 and 4I13/2 level were quantitatively analyzed according to Dexter’s theory and Inokuti–Hirayama model. The theoretical calculations are in good agreement with the observed 2.7 μm fluorescence phenomena. Results demonstrate that the Y2O3 modified germanate glass, which possesses more excellent spectroscopic properties than La2O3 modified germanate glass, might be an attractive candidate for mid-infrared laser. PMID:26279092

  4. R2O3 (R = La, Y) modified erbium activated germanate glasses for mid-infrared 2.7 μm laser materials

    NASA Astrophysics Data System (ADS)

    Cai, Muzhi; Zhou, Beier; Wang, Fengchao; Wei, Tao; Tian, Ying; Zhou, Jiajia; Xu, Shiqing; Zhang, Junjie

    2015-08-01

    Er3+ activated germanate glasses modified by La2O3 and Y2O3 with good thermal stability were prepared. 2.7 μm fluorescence was observed and corresponding radiative properties were investigated. A detailed discussion of J-O parameters has been carried out based on absorption spectra and Judd-Ofelt theory. The peak emission cross sections of La2O3 and Y2O3 modified germanate glass are (14.3 ± 0.10) × 10-21 cm2 and (15.4 ± 0.10) × 10-21 cm2, respectively. Non-radiative relaxation rate constants and energy transfer coefficients of 4I11/2 and 4I13/2 levels have been obtained and discussed to understand the 2.7 μm fluorescence behavior. Moreover, the energy transfer processes of 4I11/2 and 4I13/2 level were quantitatively analyzed according to Dexter’s theory and Inokuti-Hirayama model. The theoretical calculations are in good agreement with the observed 2.7 μm fluorescence phenomena. Results demonstrate that the Y2O3 modified germanate glass, which possesses more excellent spectroscopic properties than La2O3 modified germanate glass, might be an attractive candidate for mid-infrared laser.

  5. Superconductivity in the surface of YBa 2Cu 3O 7-δ films. Role of the charge reservoir block on the occurence of the superconductivity in one-unit-cell thick YBa 2Cu 3O 7

    NASA Astrophysics Data System (ADS)

    Shimura, Ken-ichi; Daitoh, Yoshihiro; Yano, Yoshihiko; Terashima, Takahito; Bando, Yoshichika; Matsuda, Yuji; Komiyama, Susumu

    1994-07-01

    We have studied the superconductivity in the surface of c-axis oriented ultrathin films of YBa 2Cu 3O 7-δ (YBCO) using a heterostructure of cap oxide/one-unit-cell thick (1-UCT) YBCO/PrBa 2Cu 3O 7-δ buffer layer/SrTiO 3. Atomic force microscope images of the film have revealed multi-terraces with a height of a unit cell of YBCO, indicating two-dimensional nucleation and growth. From cross-sectional transmission electron microscope observation, it has been revealed that the terminating layer of the film is a CuO layer. Cap oxides of BaO and SrO with NaCl-type structure and BaTiO 3, SrTiO 3, CaTiO 3, PbTiO 3, and CdTiO 3 with perovskite-type structure have the ability to produce superconductivity in 1-UCT YBCO. These cap oxides contain an MO ‘rocksalt’-type layer which is needed to form an MO-CuO-BaO charge reservoir block. It is required for making the superconductivity in 1-UCT YBCO that the lattice mismatch between the cap oxide and YBCO is sufficiently small (⩽6%) and the valence of M is 2+.

  6. Structure and photoluminescence properties of Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+} phosphors for solid-state lighting application

    SciTech Connect

    Wen, Dawei; Yang, Hui; Yang, Guanhui; Shi, Jianxin Wu, Mingmei Su, Qiang

    2014-05-01

    Novel phosphors of Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+} and Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+} were synthesized by a solid-state process and characterized with X-ray diffraction, photoluminescence (PL), PL excitation (PLE), and fluorescence decay time. The relationship between the observed Ce{sup 3+} emission properties and the crystal structure of Na{sub 2}Y{sub 2}B{sub 2}O{sub 7} is built and the result shows that Ce{sup 3+} ions occupy two non-equivalent Y{sup 3+} sites in the host. The codoping of Tb{sup 3+} in Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+} can tune the emitting colour from blue to green and increase the luminescence quantum efficiency to 75.2% by the energy transfer of Ce{sup 3+}→Tb{sup 3+}. The energy transfer processes of Ce{sup 3+}–Ce{sup 3+} and Ce{sup 3+}–Tb{sup 3+} are analysed and determined to be electric dipole–dipole and dipole–quadrupole, respectively. The broad PLE spectra of Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+} and Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+} are well matched with the emission from near UV LED chips, which indicates that they are promising blue and green phosphors for phosphor-converted white LEDs. - Graphical abstract: Colour-tunable phosphors Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+} with optimal quantum yield of 75.2% are synthesized and the phosphors can be served as n-UV pumped materials for LEDs. - Highlights: • Green phosphor Na{sub 2}Y{sub 2}B{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+} with quantum efficiency of 75.2% for n-UV application is synthesized. • The site occupation of Ce{sup 3+} in Na{sub 2}Y{sub 2}B{sub 2}O{sub 7} is investigated with the crystal structure and photoluminescence spectra. • The energy transfer of Ce{sup 3+}–Ce{sup 3+} and Ce{sup 3+}–Tb{sup 3+}, which is responsible to the tunable emitting colour of the phosphor, is demonstrated and the mechanism is studied.

  7. Synthesis and the crystal and molecular structures of 4-(piperidyl-1)-2-phenylpyrido[2,3-a]anthraquinone-7,12 Mono- and dibromohydrates (HL)Br . 3H{sub 2}O and (H{sub 2}L)Br{sub 2} . 3H{sub 2}O

    SciTech Connect

    Kovalchukova, O. V.; Stash, A. I.; Belsky, V. K.; Strashnova, S. B.; Zaitsev, B. E.; Ryabov, M. A.

    2009-01-15

    4-(Piperidyl-1)-2-phenylpyrido[2,3-a]anthraquinone-7,12 monobromohydrate (HL)Br . 3H{sub 2}O (I) and 4-(piperidyl-1)-2-phenylpyrido[2,3-a]anthraquinone-7,12 dibromohydrate (H{sub 2}L)Br{sub 2} . 3H{sub 2}O (II) are isolated in the crystalline state. The crystal structures of compounds I and II are determined using X-ray diffraction. It is established that the protonation of 4-(piperidyl-1)-2-phenylpyrido[2,3-a]anthraquinone-7,12 proceeds primarily through the pyridine atom at pH 2-3. The attachment of the second proton occurs through the piperidine nitrogen atom at pH {approx} 1.

  8. Integrated multilayer sputter-induced 45° YBa2Cu3O7 - x grain boundary junctions

    NASA Astrophysics Data System (ADS)

    Vuchic, B. V.; Merkle, K. L.; Dean, K. A.; Buchholz, D. B.; Chang, R. P. H.; Marks, L. D.

    1995-08-01

    A versatile multilayer technique has been developed to form 45° YBa2Cu3O7-x [001] tilt grain boundary junctions on LaAlO3 substrates. An epitaxial MgO layer is initially deposited on a (100) LaAlO3substrate using pulsed organometallic beam epitaxy (POMBE). After a pregrowth sputter treatment, an YBa2Cu3O7-x thin film is then grown using POMBE. The resultant film is c-axis oriented with a cube-on-cube orientation over the unsputtered portion of the MgO, and rotated by 45° about the [001] axis on the sputtered region of the substrate. The resulting grain boundary junction shows weak-link behavior. The advantage of this technique is the ability to place the grain boundary anywhere on the substrate in any configuration, and the potential to use any substrate upon which MgO can be epitaxially grown.

  9. Epitaxial thin-film growth of Ruddlesden-Popper-type Ba3Zr2O7 from a BaZrO3 target by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Butt, Shariqa Hassan; Rafique, M. S.; Siraj, K.; Latif, A.; Afzal, Amina; Awan, M. S.; Bashir, Shazia; Iqbal, Nida

    2016-07-01

    Ruddlesden-Popper Ba3Zr2O7 thin films have been synthesized via pulsed laser deposition (PLD) technique. The optimization of deposition parameters in PLD enables the formation of thin film of metastable Ba3Zr2O7 phase from BaZrO3 target. In order to see the post-annealing effects on the structural and optical properties, the deposited Ba3Zr2O7 thin films were annealed at 500, 600 and 800 °C. X-ray diffraction (XRD) reveals the formation of Ba3Zr2O7 phase with tetragonal structure. The changes in the surface of the deposited films were analysed by FE-SEM and AFM. The thin film post-annealed at 500 °C exhibited the best structural, optical and surface properties. Furthermore, the chemical states and chemical composition of the films were determined by X-ray photoelectron spectroscopy (XPS) near the surface. The XPS results show that Ba, Zr and O exist mainly in the form of Ba3Zr2O7 Ruddlesden-Popper-type perovskite structure.

  10. Fish IRF3 up-regulates the transcriptional level of IRF1, IRF2, IRF3 and IRF7 in CIK cells.

    PubMed

    Xu, Xiaowen; Lai, Qinan; Gu, Meihui; Liu, Dan; Hou, Qunhao; Liu, Xiancheng; Mi, Yichuan; Sun, Zhicheng; Wang, Haizhou; Lin, Gang; Hu, Chengyu

    2015-12-01

    Interferon Regulatory Factors (IRFs) belong to a family of transcription factor involved in transcriptional regulation of type I IFN and IFN-stimulated genes (ISG) in cells. In the present study, an IRF3 full-length cDNA (termed CiIRF3, JX999055) and its promoter sequence were cloned by homology cloning strategy and genome walking from grass carp (Ctenopharyngodon idella). The full-length cDNA sequence of CiIRF3 is comprised of a 5'UTR (195 bp), a 3'UTR (269 bp) and a largest open reading frame (ORF) of 1377 bp encoding a polypeptide of 458 amino acids. CiIRF3 has a conservative DNA-binding domain (DBD) at N-terminal and a relatively conserved interferon regulatory factors association domain (IAD). Phylogenetic tree analysis indicated that CiIRF3 gathers together with other IRF-3 from higher vertebrates in the same branch. The promoter sequence of CiIRF3 (596 bp) consists of three IRF-E, a C/EBP beta, a NF-kappa B and a TATA-BOX. CiIRF3 was constitutively expressed at low level in different grass carp tissues but was rapidly up-regulated with Poly I:C stimulation. To study the molecular mechanism of CiIRF3 regulating the transcription of IRFs, CiIRF3 was expressed in Escherichia coli BL21 and purified by affinity chromatography with the Ni-NTA His-Bind Resin. Gel mobility shift assays revealed the affinity of CiIRF3 protein with promoters of CiIRF1, CiIRF2, CiIRF3 and CiIRF7 respectively. Then, CIK cells were co-transfected with pcDNA3.1-CiIRF3, pGL3-promotor (pGL3-CiIRF1, pGL3-CiIRF2, pGL3-CiIRF3, pGL3-CiIRF7) and luciferase reporter vector respectively. The cotransfection experiment showed that CiIRF3 increased the promoter activity of CiIRF1, CiIRF2, CiIRF3 and CiIRF7. Furthermore, overexpression of CiIRF3 in CIK cells also up-regulated the expressions of CiIRF1, CiIRF2, CiIRF3 and CiIRF7. So, CiIRF3 can improve the transcriptional level of CiIRF1, CiIRF2, CiIRF3 and CiIRF7. PMID:26545324

  11. Synthesis and antimicrobial activity of acyclo C-nucleosides: 3-(alditol-1-yl)-7-oxo-5-phenyl-1,2,4-triazolo[4,3-a]pyrimidines.

    PubMed

    Shaban, M A; Nasr, A Z; Morgaan, A E

    2000-02-01

    Condensation of 2-hydrazino-4-oxo-6-phenylpyrimidine (1) with aldopentoses 2a-d or aldohexoses 2e-g gave the corresponding aldehydo-sugar (4-oxo-6-phenylpyrimidin-2-yl)hydrazones 3a-g which were acetylated to the corresponding poly-O-acetyl-aldehydo-sugar (3-acetyl-4-oxo-6-phenylpyrimidin-2-yl)hydrazones 4a-g. The latter compounds underwent oxidative cyclization with bromine in acetic acid and in the presence of sodium acetate to the corresponding 8-acetyl-3- (poly-O-acetyl-alditol-1-yl)-7-oxo-5-phenyl-1,2,4-triazolo[4,3-a]pyrimid ines 6a-g. Compounds 6a-g were also obtained by consecutive one-pot oxidative cyclization/acetylation in which the parent hydrazones 3a-g were treated with bromine/acetic acid/sodium acetate followed by acetic anhydride. Deacetylation of 6a-g with ammonium hydroxide in methanol gave the title compounds 7a-g. The antibacterial and antifungal activities of compounds 3c, 3f, 7c and 7f are reported. PMID:10723764

  12. Organocatalyzed enantioselective synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carboxylates

    PubMed Central

    Ramireddy, Naresh; Abbaraju, Santhi; Zhao, Cong-Gui

    2011-01-01

    The organocatalyzed enantioselective synthesis of biologically active 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carboxylate derivatives was achieved using bifunctional cinchona alkaloids as the catalysts. Using quinine thiourea as the catalyst, the tandem Michael addition-cyclization reaction between 1,3-cyclohexanediones and alkylidenecyanoacetate derivatives gives the desired products in high yields (up to 92%) and good ee values (up to 82%). PMID:22081731

  13. Millimeter-wave surface resistance of laser-ablated YBa2Cu3O(7-delta) superconducting films

    NASA Technical Reports Server (NTRS)

    Miranda, F. A.; Gordon, W. L.; Bhasin, K. B.; Warner, J. D.

    1990-01-01

    The millimeter-wave surface resistance of YBa2Cu3O(7-delta) superconducting films was measured in a gold-plated copper host cavity at 58.6 GHz between 25 and 300 K. High-quality laser-ablated films of 1.2-micron thickness were deposited on SrTiO3 and LaGaO3 substrates. Their transition temperatures were 90.0 and 88.9 K, with a surface resistance at 70 K of 82 and 116 milliohms, respectively. These values are better than the values for the gold-plated cavity at the same temperature and frequency.

  14. Combustion Synthesis of CaAl2Si2O8:Eu2+, Dy3+ And CaSrAl2SiO7:Eu2+ Long After Glow Phosphors

    NASA Astrophysics Data System (ADS)

    Talwar, Gurjeet; Joshi, C. P.; Moharil, S. V.; Kondawar, V. K.

    2011-10-01

    CaSrAl2SiO7:Eu2+ and CaAl2Si2O8:Eu2+, Dy3+ are prepared through modified combustion technique. The photoluminescence and long after glow decay characteristics are studied. PL emission spectra of both the phosphors are obtained in blue region.

  15. [Acute myeloid leukemia with monosomy 7 and inv(3)(q21q26.2) complicated with central diabetes insipidus].

    PubMed

    Nanno, Satoru; Hagihara, Kiyoyuki; Sakabe, Manami; Okamura, Hiroshi; Inaba, Akiko; Nagata, Yuki; Nishimoto, Mitsutaka; Koh, Hideo; Nakao, Yoshitaka; Nakane, Takahiko; Nakamae, Hirohisa; Shimono, Taro; Hino, Masayuki

    2013-04-01

    A 20-year-old female presented with thirst, polyposia, and polyuria and was referred to our hospital because of leukocytosis and anemia. Bone marrow aspiration revealed 66.8% myeloperoxidase-positive blasts and trilineage myelodysplasia. The karyotype was 45, XX, inv(3)(q21q26.2), -7[19]. Therefore, a diagnosis of AML with inv(3)(q21q26.2) complicated by -7 was made. Moreover, hyposthenuria and a low anti-diuretic hormone (ADH) level were observed. Although cerebrospinal fluid analysis was normal, magnetic resonance imaging (MRI) revealed the absence of hyperintensity in the neurohypophysis in T1-weighted images. Therefore, she was also diagnosed with diabetes insipidus. After she was administered a desmopressin nasal spray, the volume of urine produced decreased. Following treatment with second induction therapy containing high-dose cytarabine for AML, she achieved complete remission in the bone marrow. Moreover, when the abnormality on MRI and the volume of urine were normalized, she discontinued desmopressin. Although diabetes insipidus is a rare complication of AML, the majority of AML patients who have diabetes insipidus have the abnormal karyotypes with inv(3)(q21q26.2)/t(3;3)(q21;q26.2) and monosomy 7. Further study is required to clarify the pathogenesis and develop a strategy for the treatment of this category of AML.

  16. Induction of nitric oxide production by the cytostatic macrolide apicularen A [2,4-heptadienamide, N-[(1E)-3-[(3S,5R,7R,9S)-3,4,5,6,7,8,9,10-octahydro-7,14 dihydroxy-1-oxo-5,9-epoxy-1H-2-benzoxacyclododecin-3-yl]-1 propenyl]-, (2Z,4Z)-(9CI)] and possible role of nitric oxide in apicularen A-induced apoptosis in RAW 264.7 cells.

    PubMed

    Hong, JangJa; Yokomakura, Aya; Nakano, Yasuhiro; Ban, Hyun Seung; Ishihara, Kenji; Ahn, Jong-Woong; Zee, OkPyo; Ohuchi, Kazuo

    2005-03-01

    We previously reported that apicularen A [2,4-heptadienamide, N-[(1E)-3-[(3S,5R,7R,9S)-3,4,5,6,7,8,9,10-octahydro-7,14 dihydroxy-1-oxo-5,9-epoxy-1H-2-benzoxacyclododecin-3-yl]-1 propenyl]-, (2Z,4Z)-(9CI)], a highly cytostatic macrolide isolated from the myxobacterial genus Chondromyces, induces apoptosis in the mouse leukemic monocyte cell line RAW 264.7. To analyze the action mechanism of apicularen A for the induction of apoptosis, effects of apicularen A on nitric oxide (NO) production in RAW 264.7 cells were examined. It was demonstrated that apicularen A at 10 and 100 nM induced nitrite production, whereas apicularen B [2,4-heptadienamide, N-[(1E)-3-[(3S,5R,7R,9S)-7-[[2-(acetylamino)-2-deoxy-beta-d-glucopyranosyl]oxy]-3,4,5,6,7,8,9,10-octahydro-14-hydroxy-1-oxo-5,9-epoxy-1H-2-benzoxacyclododecin-3-yl]-1 propenyl]-, (2Z,4Z)-(9CI)], an N-acetyl-glucosamine glycoside of apicularen A, had no effect at 100 nM. The apicularen A-induced nitrite production was accompanied by an increase in the level of inducible nitric-oxide synthase (iNOS) and its mRNA and was suppressed by the NOS inhibitor N(G)-monomethyl-l-arginine acetate (l-NMMA). In addition, apicularen A activated nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) and decreased the level of IkappaB-alpha and increased that of phosphorylated c-Jun N-terminal kinase (JNK). Furthermore, the apicularen A-induced nitrite production was suppressed by the NF-kappaB inhibitor Bay 11-7082 [(E)-3-(4-methylphenylsulfonyl)-2-propenenitrile] and the JNK inhibitor SP600125 [anthra[1,9-cd]pyrazol-6(2H)-one]. These findings suggested that apicularen A activates NF-kappaB and AP-1, thus triggering the expression of iNOS mRNA and iNOS protein and induces NO production. Finally, apicularen A decreased cell growth and survival and cell viability and disrupted the mitochondrial membrane potential. The addition of l-NMMA partially recovered the apicularen A-induced decrease in cell growth and survival and cell

  17. Structural, magnetic, and magnetothermal properties of the Tb0.3Dy0.7Co2 compound

    NASA Astrophysics Data System (ADS)

    Politova, G. A.; Tereshina, I. S.; Burkhanov, G. S.; Chistyakov, O. D.; Chzhan, V. B.; Nizhankovskii, V. I.; Zaleski, A.; Kaminskaya, T. P.; Popov, V. V.

    2011-10-01

    A complex investigation of the structural, magnetic, and magnetothermal properties of the Tb0.3Dy0.7Co2 compound synthesized with the use of high-purity rare-earth metals has been performed. The phase composition has been controlled using the X-ray structural analysis, and the topology of the alloy surface has been investigated using atomic-force microscopy. It has been established that the Tb0.3Dy0.7Co2 compound is single-phase, while the samples selected for measurements possess a clearly pronounced texture. The magnetization has been measured using a vibrating-sample magnetometer in the fields up to 100 kOe in a temperature range from 4.2 to 200 K. The Curie temperature of the compound is 170 K. The data on the temperature dependence of heat capacity of Tb0.3Dy0.7Co2 have been obtained. The magnetocaloric effect Δ T has been measured by a direct method in the fields up to 18 kOe applied both along and perpendicularly to the texture axis. The anisotropic behavior of the magnitude Δ T for this compound, which possesses the cubic structure, has been found. The maximum value of the magnetocaloric effect Δ T = 2.3 K (Δ H = 18 kOe) has been observed upon applying the magnetic field along the texture axis.

  18. Remarkable changes in the photoluminescent properties of Y2Ce2O7:Eu(3+) red phosphors through modification of the cerium oxidation states and oxygen vacancy ordering.

    PubMed

    Raj, Athira K V; Prabhakar Rao, P; Sreena, T S; Sameera, S; James, Vineetha; Renju, U A

    2014-11-21

    A new series of red phosphors based on Eu(3+)-doped yttrium cerate [Y1.9Ce2O7:0.1Eu(3+), Y2Ce1.9O7:0.1Eu(3+) and Y2Ce2-xO7:xEu(3+) (x = 0.05, 0.10, 0.15, 0.20, 0.25 and 0.50)] was prepared via a conventional solid-state method. The influence of the substitution of Eu(3+) at the aliovalent site on the photoluminescent properties was determined by powder X-ray diffraction, FT Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy with energy-dispersive spectroscopy, UV-visible absorption spectroscopy, photoluminescence spectroscopy and lifetime measurements. The substitution of Eu(3+) at the Ce(4+) site induces a structural transition from a defect fluorite to a C-type structure, which increases the oxygen vacancy ordering and the distortion of the Eu(3+) environment, and decreases the formation of Ce(3+) states. In contrast, phosphors with isovalent substitution at the Y(3+) site exhibit the biphasic nature of defect fluorite and a C-type structure, thereby increasing the number of Ce(3+) oxidation states. These modifications resulted in remarkable changes in the photoluminescent properties of Y2Ce1.9O7:0.1Eu(3+) red phosphors, with emission intensities 3.8 times greater than those of the Ce0.9O2:0.1Eu(3+) and Y1.9Ce2O7:0.1Eu(3+). The photoluminescent properties of Y2Ce2-xO7:xEu(3+) were studied at different Eu(3+) concentrations under excitation with blue light. These phosphors emit intense red light due to the (5)D0-(7)F2 transition under excitation at 466 nm and no concentration quenching is observed with up to 50 mol% Eu(3+). They show increased lifetimes in the range 0.62-0.72 ms at Eu(3+) concentrations. The cation ordering linked to the oxygen vacancy ordering led to the uniform distribution of Eu(3+) ions in the lattice, thus allowing higher doping concentrations without quenching and consequently increasing the lifetime of the (5)D0 states. Our results demonstrate that significant improvements in

  19. Indoleamine 2,3-dioxygenase Activity Contributes to Local Immune Suppression in the Skin Expressing Human Papillomavirus Oncoprotein E7

    PubMed Central

    Mittal, D; Kassianos, AJ; Tran, LS; Bergot, AS; Gosmann, C; Hofmann, J; Blumenthal, A; Leggatt, GR; Frazer, IH

    2013-01-01

    Chronic infection of anogenital epithelium with human papillomavirus (HPV) promotes development of cancer. Many pathogens evoke immunosuppressive mechanisms to enable persistent infection. We have previously shown that grafted skin expressing HPV16 E7 oncoprotein from a keratin-14 promoter (K14E7) is not rejected by a syngeneic, immunocompetent host. In this study we show that indoleamine 2, 3-dioxygenase (IDO) 1, an IFN-γ inducible immunoregulatory molecule, is more highly expressed by langerin−ve dermal dendritic cells from K14E7 skin than nontransgenic control skin. Furthermore, inhibiting IDO activity using 1-D/L-methyl tryptophan promotes K14E7 skin graft rejection. Increased IDO1 expression and activity in K14E7 skin requires IFN-γ and iNKT cells, both of which have been shown to negatively regulate T-cell effector function and suppress K14E7 graft rejection. Further, dendritic cells from K14E7 skin express higher level of IFN-γ receptor (IFN-γR) than dendritic cells from control skin. K14E7 transgenic skin recruits significantly higher number of dendritic cells, independent of IFN-γ and IFN-γR expression. Consistent with these observations in a murine model, we found higher expression of IDO1 and IFN-γ but not IDO2 in the cervical epithelium of patients with HPV-associated cervical intraepithelial neoplasia (CIN) 2/3. Our data support a hypothesis that induction of IDO1 in HPV infected skin contributes to evasion of host immunity. PMID:23652797

  20. CYP1A2 DOES NOT PLAY A CRITICAL ROLE IN 2, 3 7, 8-TETRACHLORODIBENZO-P-DIOXIN-INDUCED IMMUNOSUPRESSION

    EPA Science Inventory

    CYP1A2 IS NOT REQUIRED FOR 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN-INDUCED IMMUNOSUPPRESSION Smialowicz, Ralph J1; Burgin, Deborah E2; Williams, Wanda C1; Diliberto, Janet J1; Birnbaum, Linda S1
    1 Experimental Toxicology Division, US EPA, RTP, NC, USA; 2Curriculum in Toxicology, U...

  1. YBa2Cu3O(7-x)/Au/Nb device structures

    NASA Technical Reports Server (NTRS)

    Hunt, B. D.; Foote, M. C.; Bajuk, L.; Vasquez, R. P.

    1991-01-01

    Fabrication and testing of planar and edge geometry YBaCuO/Au/Nb superconductor/normal-metal/superconductor (SNS) device structures is described. Weak-link devices of this type serve as sensitive probes of the electrical quality of the YBaCuO/Au interface. The devices are fabricated using laser-ablated, in situ, c-axis-oriented YBaCuO thin films, with both annealed and unannealed YBaCuO/Au interfaces. The planar SNS structures are formed by sequential, in situ deposition of YBaCuO, Au, and Nb, followed by etching, planarization, and wiring electrode definition to produce junctions ranging from 5 to 20 micron on a side. Resulting RnA products are 1-10 x 10 to the -8th ohm-sq cm with critical current densities up to 5 kA/sq cm. For the edge geometry devices, the YBaCuO film edges are patterned using Ar ion milling, followed by a low energy ion cleaning step and in situ deposition of Au and Nb. Devices with areas in the 10 to the -7th to 10 to the -8th sq cm range have been fabricated with RnA products lower than 10 to the -8th ohm-sq cm and critical current densities up to 3kA/sq cm. Both types of devices show ac Josephson steps under microwave irradiation. The best results have been obtained with annealed YBaCuO/Au interfaces.

  2. β-Zn3BPO7:Mn2+: A novel rare-earth-free possible deep-red emitting phosphor

    NASA Astrophysics Data System (ADS)

    Han, Bing; Li, Pengju; Zhang, Jie; Jin, Lin; Luo, Wen; Shi, Hengzhen

    2015-04-01

    Novel rare-earth-free deep-red emitting phosphors, β-Zn3(1-x)Mn3xBPO7, were prepared successfully by high temperature solid-state reaction and their photoluminescence properties were investigated. The excitation spectrum consists of a broad excitation band peaking at 255 nm and a group of line-shaped excitation peaks around 350 nm and 500 nm, which can be attributed to the charge transfer transition in Mn2+-O2- bonds and the inner d-d electron transitions of Mn2+ ion, respectively. The emission bands are due to 4T1(4G) → 6A1(6S) transition of the Mn2+ ion and there exists efficient energy transfer from charge transfer state of Mn2+-O2- bonds to Mn2+ ions. The dependence of emission wavelength on Mn2+ concentration is studied. The decay curve of Mn2+ ions luminescence in β-Zn3BPO7:Mn2+ is also measured.

  3. QSPR study of solvent quenching of the 5D 0 → 7F 2 emission of Eu(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate) 3

    NASA Astrophysics Data System (ADS)

    Mercader, Andrew G.; Duchowicz, Pablo R.; Fernández, Francisco M.; Castro, Eduardo A.; Wolcan, Ezequiel

    2008-09-01

    We performed a predictive analysis, based on quantitative structure-property relationships (QSPR), of the luminescence lifetime ( τ) of Eu(fod) 3 in different solvents. The Eu(fod) 3 luminescent properties have been helpful as replacements for radioactivity, alternatives to standard fluorescent dyes and donors in energy transfer experiments, and are gaining expanding applications in wide variety of bioanalytical assays. Our best QSPR linear model constructed from 23 molecular structures combines four molecular descriptors, selected from more than a thousand geometrical, topological, quantum-mechanical and electronic types of descriptors.

  4. A novel α4/7-conotoxin LvIA from Conus lividus that selectively blocks α3β2 vs. α6/α3β2β3 nicotinic acetylcholine receptors

    PubMed Central

    Luo, Sulan; Zhangsun, Dongting; Schroeder, Christina I.; Zhu, Xiaopeng; Hu, Yuanyan; Wu, Yong; Weltzin, Maegan M.; Eberhard, Spencer; Kaas, Quentin; Craik, David J.; McIntosh, J. Michael; Whiteaker, Paul

    2014-01-01

    This study was performed to discover and characterize the first potent α3β2-subtype-selective nicotinic acetylcholine receptor (nAChR) ligand. A novel α4/7-conotoxin, α-CTxLvIA, was cloned from Conus lividus. Its pharmacological profile at Xenopus laevis oocyte-expressed rat nAChR subtypes was determined by 2-electrode voltage-clamp electrophysiology, and its 3-dimensional (3D) structure was determined by NMR spectroscopy. α-CTx LvIA is a 16-aa C-terminally-amidated peptide with 2-disulfide bridges. Using rat subunits expressed in Xenopus oocytes, we found the highest affinity of α-CTxLvIA was for α3β2 nAChRs (IC50 8.7 nM), where blockade was reversible within 2 min. IC50 values were >100 nM at α6/α3β2β3, α6/α3β4, and α3β4 nAChRs, and ≥3 μM at all other subtypes tested. α3β2 vs. α6β2 subtype selectivity was confirmed for human-subunit nAChRs with much greater preference (300-fold) for α3β2 over α6β2 nAChRs. This is the first α-CTx reported to show high selectivity for human α3β2 vs. α6β2 nAChRs. α-CTxLvIA adopts two similarly populated conformations water: one (assumed to be bioactive) is highly structured, whereas the other is mostly random coil in nature. Selectivity differences with the similarly potent, but less selective, α3β2 nAChR antagonist α-CTx PeIA probably reside within the three residues, which differ in loop 2, given their otherwise similar 3D structures. α4/7-CTx LvIA is a new, potent, selective α3β2 nAChR antagonist, which will enable detailed studies of α3β2 nAChR structure, function, and physiological roles.—Luo, S., Zhangsun, D., Schroeder, C. I., Zhu, X., Hu, Y., Wu, Y., Weltzin, M. M., Eberhard, S., Kaas, Q., Craik, D. J., McIntosh, J. M., Whiteaker, P. A novel α4/7-conotoxin LvIA from Conus lividus that selectively blocks α3β2 vs. α6/α3β2β3 nicotinic acetylcholine receptors. PMID:24398291

  5. The anisotropic nature of the superconducting properties of single crystal Y 1Ba 2Cu 3O 7 - x

    NASA Astrophysics Data System (ADS)

    Worthington, T. K.; Gallagher, W. J.; Kaiser, D. L.; Holtzberg, F. H.; Dinger, T. R.

    1988-06-01

    A series of noncontact magnetic measurements on high-quality single crystals of Y 1Ba 2Cu 3O 7 - x have enabled us to demonstrate that the superconducting-state properties of Y 1Ba 2Cu 3O 7 - x are those of a conventional, anisotropic superconductor with the anisotropy being associated with the highly conducting Cu sbnd O sheets in the Y 1Ba 2Cu 3O 7 - x crystal structure. The anisotropy in the superconducting state is reflected most strongly in the critical current anisotropy, which is as large as 20 to 1 at low temperatures and low fields and gets arbitrarily large at higher temperatures and higher fields. The upper critical field H C2 shows an anisotropy that varies from 6:1 to 10:1 in different crystals of high quality. Along the copper-oxygen sheets the upper critical field is enormous, extrapolating to ∼60 Tesla by 77 K and implying a low-temperature Ginzburg-Landau coherence length normal to the layers of 2Å- 4Å. Strong upward curvature is evident in the H C2 data in both orientations of applied field. This curvature can be interpreted in terms of thermodynamic fluctuations, and, if this explanation is correct, the critical region is enormous, extending more than 25 K below T C.

  6. Visible and infrared luminescence properties of Er{sup 3+}-doped Y{sub 2}Ti{sub 2}O{sub 7} nanocrystals

    SciTech Connect

    Ting, Chu-Chi; Chiu, Yi-Shan; Chang, Chia-Wei; Chuang, Liang-Chih

    2011-03-15

    Er{sup 3+}-doped Y{sub 2}Ti{sub 2}O{sub 7} nanocrystals were fabricated by the sol-gel method. While the annealing temperature exceeds 757 {sup o}C, amorphous pyrochlore phase Er{sub x}Y{sub 2-x}Ti{sub 2}O{sub 7} transfers to well-crystallized nanocrystals, and the average crystal size increases from {approx}70 to {approx}180 nm under 800-1000 {sup o}C/1 h annealing. Er{sub x}Y{sub 2-x}Ti{sub 2}O{sub 7} nanocrystals absorbing 980 nm photons can produce the upconversion (526, 547, and 660 nm; {sup 2}H{sub 11/2}{yields}{sup 4}I{sub 15/2}, {sup 4}S{sub 3/2}{yields}{sup 4}I{sub 15/2}, and {sup 4}F{sub 9/2}{yields}{sup 4}I{sub 15/2}, respectively) and Stokes (1528 nm; {sup 4}I{sub 13/2}{yields}{sup 4}I{sub 15/2}) photoluminescence (PL). The infrared PL decay curve is single-exponential for Er{sup 3+} (5 mol%)-doped Y{sub 2}Ti{sub 2}O{sub 7} nanocrystals but slightly nonexponential for Er{sup 3+} (10 mol%)-doped Y{sub 2}Ti{sub 2}O{sub 7} nanocrystals. For 5 and 10 mol% doping concentrations, the mechanism of up-converted green light is the two-photon excited-state absorption. Much stronger intensity of red light relative to green light was observed for the sample with 10 mol% dopant. This phenomenon can be attributed to the reduced distance between Er{sup 3+}-Er{sup 3+} ions, resulting in the enhancement of the energy-transfer upconversion and cross-relaxation mechanisms. -- Graphical Abstract: Emission fluorescence spectra of the Er{sup 3+} (3, 5, 7, or 10 mol%)-doped Y{sub 2}Ti{sub 2}O{sub 7} nanocrystals annealed at 800 {sup o}C for 1 h under 980 nm pumping. The Er{sup 3+}-doped Y{sub 2}Ti{sub 2}O{sub 7} nanocrystals absorbing 980 nm photons can produce the upconversion (526, 547, and 660 nm; {sup 2}H{sub 11/2}{yields}{sup 4}I{sub 15/2}, {sup 4}S{sub 3/2}{yields}{sup 4}I{sub 15/2}, and {sup 4}F{sub 9/2}{yields}{sup 4}I{sub 15/2}, respectively) and Stokes (1528 nm; {sup 4}I{sub 13/2}{yields}{sup 4}I{sub 15/2}) photoluminescence. Display Omitted Research highlights

  7. Millimeter wave surface resistance of RBa2Cu3O(7-delta) (R=Y,Eu,Dy,Sm,Er) superconductors

    NASA Technical Reports Server (NTRS)

    Miranda, F. A.; Gordon, W. L.; Eck, T. G.; Bhasin, K. B.; Warner, J. D.; Jenkins, K. A.

    1990-01-01

    The measurements are reported of the millimeter wave surface resistance R(sub s) at 58.6 GHz of bulk samples of RBa2Cu3O(7-delta) (R = Y,Eu,Dy,Sm,Er) and of YBa2Cu3O(7-delta) superconducting films, in the temperature range from 20 to 300 K. The bulk samples were prepared by cold pressing the powders of RBa2Cu3O(7-delta) into one in. disks. The powders were prepared by several sinterings in one atmosphere of oxygen at 925 C, with grindings between sinterings, to obtain the superconducting phase. The thin films were deposited on SrTiO3 and LaGaO3 substrates by pulsed laser ablation. Each sample was measured by replacing the end wall of a gold-plated Te sub 013 circular mode copper cavity with the sample and determining the cavity quality factor . From the difference in the Q-factor of the cavity, with and without the sample, the R(sub s) of the sample was determined.

  8. Ethyl 2,7,7-trimethyl-4-(1-methyl-1H-indol-3-yl)-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate.

    PubMed

    Oztürk Yildirim, Sema; Butcher, Ray J; Gündüz, Miyase Gözde; El-Khouly, Ahmed; Simşek, Rahime; Safak, Cihat

    2013-01-01

    In the title mol-ecule, C24H28N2O3, the cyclo-hexene ring is in a sofa conformation and the 1,4-dihydro-pyridine ring is in a slight boat conformation. In the indole ring system, the pyrrole and benzene rings form a dihedral angle of 2.63 (7)°. In the crystal, N-H⋯O hydrogen bonds connect the mol-ecules into C(6) chains parallel to the b axis and pairs of weak C-H⋯O hydrogen bonds link inversion-related chains into a ladder motif through R2(2)(18) rings. A weak intra-molecular C-H⋯O hydrogen bond is also observed. PMID:23476426

  9. MSRB7 reverses oxidation of GSTF2/3 to confer tolerance of Arabidopsis thaliana to oxidative stress

    PubMed Central

    Lee, Shu-Hong; Li, Chia-Wen; Koh, Kah Wee; Chuang, Hsin-Yu; Chen, Yet-Ran; Lin, Choun-Sea; Chan, Ming-Tsair

    2014-01-01

    Methionine sulfoxide reductases (MSRs) catalyse the reduction of oxidized methionine residues, thereby protecting proteins against oxidative stress. Accordingly, MSRs have been associated with stress responses, disease, and senescence in a taxonomically diverse array of organisms. However, the cytosolic substrates of MSRs in plants remain largely unknown. Here, we used a proteomic analysis strategy to identify MSRB7 substrates. We showed that two glutathione transferases (GSTs), GSTF2 and GSTF3, had fewer oxidized methionine (MetO) residues in MSRB7-overexpressing Arabidopsis thaliana plants than in wild-type plants. Conversely, GSTF2 and GSTF3 were highly oxidized and unstable in MSRB7-knockdown plants. MSRB7 was able to restore the MetO-GSTF2M100/104 and MetO-GSTF3M100 residues produced during oxidative stress. Furthermore, both GSTs were specifically induced by the oxidative stress inducer, methyl viologen. Our results indicate that specific GSTs are substrates of MSRs, which together provide a major line of defence against oxidative stress in A. thaliana. PMID:24962998

  10. Line-of-sight displacement from ALOS-2 interferometry: Mw 7.8 Gorkha Earthquake and Mw 7.3 aftershock

    NASA Astrophysics Data System (ADS)

    Lindsey, Eric O.; Natsuaki, Ryo; Xu, Xiaohua; Shimada, Masanobu; Hashimoto, Manabu; Melgar, Diego; Sandwell, David T.

    2015-08-01

    Interferometric synthetic aperture radar (InSAR) is a key tool for the analysis of displacement and stress changes caused by large crustal earthquakes, particularly in remote areas. A challenge for traditional InSAR has been its limited spatial and temporal coverage especially for very large events, whose dimensions exceed the typical swath width of 70-100 km. This problem is addressed by the ALOS-2 satellite, whose PALSAR-2 instrument operates in ScanSAR mode, enabling a repeat time of 2 weeks and a swath width of 350 km. Here we present InSAR line-of-sight displacement data from ALOS-2/PALSAR-2 observations covering the Mw 7.8 Gorkha, Nepal earthquake and its Mw 7.3 aftershock that were acquired within 1 week of each event. The data are made freely available and we encourage their use in models of the fault slip and associated stress changes. The Mw 7.3 aftershock not only extended the rupture area of the main shock toward the east but also left a 20 km gap where the fault has little or no coseismic slip. We estimate this unslipped fault patch has the potential to generate a Mw 6.9 event.

  11. Protein Kinase CK2 Interacts at the Neuromuscular Synapse with Rapsyn, Rac1, 14-3-3γ, and Dok-7 Proteins and Phosphorylates the Latter Two*

    PubMed Central

    Herrmann, Dustin; Straubinger, Marion; Hashemolhosseini, Said

    2015-01-01

    Previously, we demonstrated that the protein kinase CK2 associates with and phosphorylates the receptor tyrosine kinase MuSK (muscle specific receptor tyrosine kinase) at the neuromuscular junction (NMJ), thereby preventing fragmentation of the NMJs (Cheusova, T., Khan, M. A., Schubert, S. W., Gavin, A. C., Buchou, T., Jacob, G., Sticht, H., Allende, J., Boldyreff, B., Brenner, H. R., and Hashemolhosseini, S. (2006) Genes Dev. 20, 1800–1816). Here, we asked whether CK2 interacts with other proteins involved in processes at the NMJ, which would be consistent with the previous observation that CK2 appears enriched at the NMJ. We identified the following proteins to interact with protein kinase CK2: (a) the α and β subunits of the nicotinic acetylcholine receptors with weak interaction, (b) dishevelled (Dsh), and (c) another four proteins, Rapsyn, Rac1, 14-3-3γ, and Dok-7, with strong interaction. CK2 phosphorylated 14-3-3γ at serine residue 235 and Dok-7 at several serine residues but does not phosphorylate Rapsyn or Rac1. Furthermore, phosphomimetic Dok-7 mutants aggregated nicotinic acetylcholine receptors in C2C12 myotubes with significantly higher frequency than wild type Dok-7. Additionally, we mapped the interacting epitopes of all four binding partners to CK2 and thereby gained insights into the potential role of the CK2/Rapsyn interaction. PMID:26198629

  12. Protein kinase CK2 interacts at the neuromuscular synapse with Rapsyn, Rac1, 14-3-3γ, and Dok-7 proteins and phosphorylates the latter two.

    PubMed

    Herrmann, Dustin; Straubinger, Marion; Hashemolhosseini, Said

    2015-09-11

    Previously, we demonstrated that the protein kinase CK2 associates with and phosphorylates the receptor tyrosine kinase MuSK (muscle specific receptor tyrosine kinase) at the neuromuscular junction (NMJ), thereby preventing fragmentation of the NMJs (Cheusova, T., Khan, M. A., Schubert, S. W., Gavin, A. C., Buchou, T., Jacob, G., Sticht, H., Allende, J., Boldyreff, B., Brenner, H. R., and Hashemolhosseini, S. (2006) Genes Dev. 20, 1800-1816). Here, we asked whether CK2 interacts with other proteins involved in processes at the NMJ, which would be consistent with the previous observation that CK2 appears enriched at the NMJ. We identified the following proteins to interact with protein kinase CK2: (a) the α and β subunits of the nicotinic acetylcholine receptors with weak interaction, (b) dishevelled (Dsh), and (c) another four proteins, Rapsyn, Rac1, 14-3-3γ, and Dok-7, with strong interaction. CK2 phosphorylated 14-3-3γ at serine residue 235 and Dok-7 at several serine residues but does not phosphorylate Rapsyn or Rac1. Furthermore, phosphomimetic Dok-7 mutants aggregated nicotinic acetylcholine receptors in C2C12 myotubes with significantly higher frequency than wild type Dok-7. Additionally, we mapped the interacting epitopes of all four binding partners to CK2 and thereby gained insights into the potential role of the CK2/Rapsyn interaction.

  13. Magnetic memory based on La{sub 0.7}Ca{sub 0.3}MnO{sub 3}/YBa{sub 2}Cu{sub 3}O{sub 7}/La{sub 0.7}Ca{sub 0.3}MnO{sub3} ferromagnet/superconductor hybrid structures.

    SciTech Connect

    Nemes, N. M.; Visani, C.; Leon, C.; Garcia-Hernandez, M.; Simon, F.; Feher, T.; te Velthuis, S. G. E.; Hoffmann, A.; Santamaria, J.; Materials Science Division; Univ. Complutense de Madrid; Inst. de Ciencia de Materiales de Madrid; Budapest Univ. of Technology; Hungarian Academy of Sciences

    2010-01-01

    We report a memory concept utilizing ferromagnet/superconductor/ferromagnet La{sub 0.7}Ca{sub 0.3}MnO{sub 3}/YBa{sub 2}Cu{sub 3}O{sub 7}/La{sub 0.7}Ca{sub 0.3}MnO{sub 3} thin film hybrid structures. The orientation of the magnetic field with respect to the ferromagnetic easy axis has a strong effect on superconductivity as indicated by a strong variation in the magnetoresistance (MR). MR can be controlled by rotating a small magnetic field applied in the plane of the film in a way that is determined by the in-plane biaxial magnetic anisotropy. The proposed memory device has the advantages of superconducting detection elements (fast response and low dissipation), small (100-150 Oe) writing fields, and resistance read-out without need for applied field.

  14. Symmetrical interfacial reconstruction and magnetism in La{sub 0.7}Ca{sub 0.3}MnO{sub 3}/YBa{sub 2}Cu{sub 3}O{sub 7}/La{sub 0.7}Ca{sub 0.3}MnO{sub 3} heterostructures.

    SciTech Connect

    Visani, C.; Tornos, J.; Nemes, N. M.; Rocci, M.; Leon, C.; Santamaria, J.; te Velthuis, S. G. E.; Liu, Y.; Hoffmann, A.; Freeland, J. W.; Garcia-Hernandez, M.; Fitzsimmons, M. R.; Kirby, B. J.; Varela, M.; Pennycock, S. J.

    2011-01-01

    We have analyzed the interface structure and composition of La{sub 0.7}Ca{sub 0.3}MnO{sub 3}/YBa{sub 2}Cu{sub 3}O{sub 7}/La{sub 0.7}Ca{sub 0.3}MnO{sub 3} trilayers by combined polarized neutron reflectometry, aberration-corrected microscopy, and atomic column resolution electron-energy-loss spectroscopy and x-ray absorption with polarization analysis. We find the same stacking sequence at both top and bottom cuprate interfaces. X-ray magnetic circular dichroism experiments show that both cuprate interfaces are magnetic with a magnetic moment induced in Cu atoms as expected from symmetric Mn-O-Cu superexchange paths. These results supply a solid footing for the applicability of recent theories explaining the interplay between magnetism and superconductivity in this system in terms of the induced Cu spin polarization at both interfaces.

  15. Structure cristalline et etude par spectrometrie de vibration (IR et Raman) du bis(ethylenediammonium) diphosphate (NH 3(CH 2) 2NH 3) 2 · P 2O 7

    NASA Astrophysics Data System (ADS)

    Kamoun, Slaheddine; Jouini, Amor; Daoud, Abdelaziz

    1992-07-01

    Classical methods extensively known for the synthesis of inorganic condensed phosphates are used to give compounds that are intermediate between inorganic and organic. We prepared the title compound to examine the possibility of using, in this new field, the ion exchange resin and Boullé's methods. Chemical preparation, crystal structure, and vibrational studies are given for a new diphosphate. The bis(ethylenediammonium) diphosphate salt is monoclinic with the unit cell dimensions a = 8.724(1), b = 13.511(2), c = 10.039(1)Å, β = 96.25(1)°, V = 1176.3(5)Å 3, Dm = 1.673Mg m -3, D x = 1.684Mg m -3, μ = 2.163 mm -1, space group C2 c with Z = 4. The structure was solved by the Patterson method and refined to a final R value of 0.059 for 2602 observed independent reflections. The P sbnd O(L) sbnd P bridge is symmetrical with a P sbnd O(L) distance of 1.570(1)Åand a POP angle of 141.94(7)°. The P 2O 4-7 anions are located around the twofold axis. The ethylenediammonium dications have a trans configuration. Half of them, having a crystallographic inversion center, are located in channels delimited by the diphosphate anions. The others, located around the twofold axis, are sandwiched along the c axis between two diphosphate anions. The cohesion and the stability of the atomic arrangement result from the N sbnd H···O hydrogen bonds. The IR and Raman spectra of [NH 3(CH) 2NH 32 · P 2O 7 are recorded and analyzed. From the spectra it is inferred that the P 2O 4-7 anion has a C2 symmetry in the crystal; all the POP modes (stretching and bending) are active in IR and Raman.

  16. Infrared Spectroscopic Evidences of Strong Electronic Correlations in (Sr1‑xLax)3Ir2O7

    NASA Astrophysics Data System (ADS)

    Ahn, Gihyeon; Song, S. J.; Hogan, T.; Wilson, S. D.; Moon, S. J.

    2016-09-01

    We report on infrared spectroscopic studies of the electronic response of the (Sr1‑xLax)3Ir2O7 system. Our experiments revealed hallmarks of strong electronic correlations in the evolution of the electronic response across the filling-controlled insulator-metal transition. We observed a collapse of the Jeff = 1/2 Mott gap accompanying the transfer of the spectral weight from the high-energy region to the gap region with electron doping. The intraband conductivity at the metallic side of the transition was found to consist of coherent Drude-like and incoherent responses. The sum rule and the extended Drude model analyses further indicated a large mass enhancement. Our results demonstrate a critical role of the electronic correlations in the charge dynamics of the (Sr1‑xLax)3Ir2O7 system.

  17. Infrared Spectroscopic Evidences of Strong Electronic Correlations in (Sr1−xLax)3Ir2O7

    PubMed Central

    Ahn, Gihyeon; Song, S. J.; Hogan, T.; Wilson, S. D.; Moon, S. J.

    2016-01-01

    We report on infrared spectroscopic studies of the electronic response of the (Sr1−xLax)3Ir2O7 system. Our experiments revealed hallmarks of strong electronic correlations in the evolution of the electronic response across the filling-controlled insulator-metal transition. We observed a collapse of the Jeff = 1/2 Mott gap accompanying the transfer of the spectral weight from the high-energy region to the gap region with electron doping. The intraband conductivity at the metallic side of the transition was found to consist of coherent Drude-like and incoherent responses. The sum rule and the extended Drude model analyses further indicated a large mass enhancement. Our results demonstrate a critical role of the electronic correlations in the charge dynamics of the (Sr1−xLax)3Ir2O7 system. PMID:27599573

  18. The thermodynamic properties of 4,5,9,10-tetrahydropyrene and 1,2,3,6,7,8-hexahydropyrene

    SciTech Connect

    Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A.; Smith, N.K.; Steele, W.V.

    1992-12-01

    Measurements leading to the calculation of the ideal-gas thermodynamic properties are reported for 4,5,9,10-tetrahydropyrene and 1,2,3,6,7,8-hexahydropyrene. Experimental methods included combustion calorimetry, adiabatic heat-capacity calorimetry, vibrating-tube densitometry, comparative ebulliometry, inclined-piston gauge manometry, and differential-scanning calorimetry (d.s.c.). Critical properties were estimated for both materials based on the measurement results. Entropies, enthalpies, and Gibbs energies of formation were derived for the ideal gases for selected temperatures between 380 K and 700 K. The property-measurement results reported here for 4,5,9,10-tetrahydropyrene and 1,2,3,6,7,8-hexahydropyrene are the first for these important intermediates in the pyrene/H{sub 2} hydrogenation reaction network.

  19. Infrared Spectroscopic Evidences of Strong Electronic Correlations in (Sr1-xLax)3Ir2O7.

    PubMed

    Ahn, Gihyeon; Song, S J; Hogan, T; Wilson, S D; Moon, S J

    2016-01-01

    We report on infrared spectroscopic studies of the electronic response of the (Sr1-xLax)3Ir2O7 system. Our experiments revealed hallmarks of strong electronic correlations in the evolution of the electronic response across the filling-controlled insulator-metal transition. We observed a collapse of the Jeff = 1/2 Mott gap accompanying the transfer of the spectral weight from the high-energy region to the gap region with electron doping. The intraband conductivity at the metallic side of the transition was found to consist of coherent Drude-like and incoherent responses. The sum rule and the extended Drude model analyses further indicated a large mass enhancement. Our results demonstrate a critical role of the electronic correlations in the charge dynamics of the (Sr1-xLax)3Ir2O7 system. PMID:27599573

  20. Fermi surface and order parameter driven vortex lattice structure transitions in twin-free YBa2Cu3O7.

    PubMed

    White, J S; Hinkov, V; Heslop, R W; Lycett, R J; Forgan, E M; Bowell, C; Strässle, S; Abrahamsen, A B; Laver, M; Dewhurst, C D; Kohlbrecher, J; Gavilano, J L; Mesot, J; Keimer, B; Erb, A

    2009-03-01

    We report on small-angle neutron scattering studies of the intrinsic vortex lattice (VL) structure in detwinned YBa2Cu3O7 at 2 K, and in fields up to 10.8 T. Because of the suppressed pinning to twin-domain boundaries, a new distorted hexagonal VL structure phase is stabilized at intermediate fields. It is separated from a low-field hexagonal phase of different orientation and distortion by a first-order transition at 2.0(2) T that is probably driven by Fermi surface effects. We argue that another first-order transition at 6.7(2) T, into a rhombic structure with a distortion of opposite sign, marks a crossover from a regime where Fermi surface anisotropy is dominant, to one where the VL structure and distortion is controlled by the order-parameter anisotropy. PMID:19392554

  1. Solid-phase synthesis of 2-substituted 4-amino-7-oxo-5,6,7,8-tetrahydropyrido[2,3-d]pyrimidines.

    PubMed

    Falcó, José L; Borrell, José I; Teixidó, Jordi

    2003-01-01

    An efficient solid-phase synthesis of 2-substituted 4-aminopyrido[2,3-d]pyrimidines 15 is reported. The procedure started by solid supporting a p-hydroxybenzaldehyde 8 to the Wang resin by using the Mitsunobu protocol. The resulting aldehyde 17 was treated with a substituted acid methyl malonate 10 to afford the corresponding alpha, beta-unsaturated ester 18, which was converted to the Michael adduct 21 by reaction with malononitrile. Cyclization of 21 with an amidine system 13 yielded the solid supported pyridopyrimidine 22, which afforded the corresponding 2-substituted 4-aminopyrido[2,3-d]pyrimidine 15 upon treatment with TFA:DCM. Compounds 15 present three diversity centers R1, R2 and R3. Having validated the chemistry on solid support, a 32-membered combinatorial library was obtained using this protocol.

  2. The effects of space radiation on thin films of YBa2Cu3O(7-x)

    NASA Technical Reports Server (NTRS)

    Herschitz, R.; Bogorad, A.; Bowman, C.; Seehra, S. S.; Mogro-Campero, A.; Turner, L. G.

    1991-01-01

    This investigation had two objectives: (1) to determine the effects of space radiation on superconductor parameters that are most important in space applications; and (2) to determine whether this effect can be simulated with Co-60 gamma rays, the standard test method for space materials. Thin films of yttrium barium copper oxide (YBCO) were formed by coevaporation of Y, BaF2, and Cu and post-annealing in wet oxygen at 850 C for 3.5 h. The substrate used was (100) silicon with an evaporated zirconia buffer layer. The samples were characterized by four point probe electrical measurements as a function of temperature. The parameters measured were the zero resistance transition temperature T(sub c) and the room temperature resistance. The samples were then exposed to Co-60 gamma-rays in air and in pure nitrogen, and to 780 keV electrons, in air. The parameters were then remeasured. The results are summarized. The results indicate little or no degradation in the parameters measured for samples exposed up to 10 Mrads of gamma-rays in nitrogen. However, complete degradation is preliminarily attributed to the high level of ozone generated in the chamber by the gamma-ray interaction with air. It can be concluded that: (1) the electron component of space radiation does not degrade the critical temperature of the YBCO films described, at least for energies around 800 keV and doses similar to those received by surface materials on spacecraft in typical remote sensing missions; and (2) for qualifying this and other superconducting materials against the space-radiation threat the standard test method used in the aerospace industry, namely, exposure to Co-60 gamma-rays in air, may require some further investigation. As a minimum, the sample must be either in vacuum or in positive nitrogen pressure.

  3. An Efficient Solution-Phase Synthesis of 4,5,7-Trisubstituted Pyrrolo[3,2-d]pyrimidines

    PubMed Central

    Zhang, Weihe; Liu, Jing; Stashko, Michael A.; Wang, Xiaodong

    2013-01-01

    We have developed an efficient and robust route to synthesize 4,5,7-trisubstituted pyrrolo[3,2-d]pyrimidines as potent kinase inhibitors. This solution-phase synthesis features a SNAr substitution reaction, cross-coupling reaction, one-pot reduction/reductive amination and N-alkylation reaction. These reactions occur rapidly with high yields and have broad substrate scopes. A variety of groups can be selectively introduced into the N5 and C7 positions of 4,5,7-trisubstituted pyrrolopyrimidines at a late stage of the synthesis, thereby providing a highly efficient approach to explore the structure-activity relationships of pyrrolopyrimidine derivatives. Four synthetic analogs have been profiled against a panel of 48 kinases and a new and selective FLT3 inhibitor 9 is identified. PMID:23181516

  4. 2.7 μm fluorescence and energy transfer in Er{sup 3+} doped germanosilicate glasses

    SciTech Connect

    Wei, Tao; Jing, Xufeng; Tian, Ying; Chen, Fangze; Wang, Fengchao; Xu, Shiqing

    2014-06-01

    Highlights: • Novel Er{sup 3+} doped germanosilicate glasses were synthesized. • Excellent thermal stability and 2.7 μm emission properties were obtained. • High A{sub rad} (33.75 s{sup −1}) and emission cross section (1.90 × 10{sup −20} cm{sup 2}) were achieved. • A reasonable energy transfer mechanism was put forward. - Abstract: 2.7 μm fluorescence has been achieved for the first time in Er{sup 3+} doped novel germanosilicate glasses. Thermal stability, spectroscopic properties and energy transfer mechanism have been investigated in detail. Moreover, the spontaneous transition probability (A{sub rad}) and emission cross section of samples were calculated and analyzed. The prepared Er{sup 3+} doped germanosilicate glasses possessing excellent thermal stability, high A{sub rad} (33.75 s{sup −1}) and emission cross section of 2.7 μm (1.90 × 10{sup −20} cm{sup 2}) provide a new material for the realization of mid-infrared fiber lasers.

  5. 1,3,4,6,7,9-Hexamethylbenzo[1,2-c:3,4-c':5,6-c'']trithiophene: a twisted heteroarene.

    PubMed

    Wu, Yao-Ting; Tai, Chia-Cheng; Lin, Wei-Chih; Baldridge, Kim K

    2009-07-01

    1,3,4,6,7,9-Hexamethylbenzo[1,2-c:3,4-c':5,6-c'']trithiophene (C-Me) was prepared by palladium-catalyzed methylations of the corresponding hexabromide C-Br. The twisted structure of C-Me has been confirmed by X-ray crystal analysis. The physical properties of twisted C-Me and planar benzo[1,2-c:3,4-c':5,6-c'']trithiophene (C-H) were studied and compared. Crystal structures are compared to computational structures determined using density functional theory, with both the M06-2X and B3PW91 functionals.

  6. Development and field validation of a multimedia exposure assessment model for waste load allocation in aquatic ecosystems: Application to 2,3,7,8-tetrachlorodibenzo-p-dioxin and 2,3,7,8-tetrachlorodibenzofuran in the Fraser River Watershed

    SciTech Connect

    Gobas, F.A.P.; Pasternak, J.P.; Lien, K.; Duncan, R.K.

    1998-08-15

    Knowledge of the relationship between contaminant emissions and ambient concentrations is crucial in achieving environmental quality objectives. This paper reports the development and field validation of EcoFate, a time dependent multimedia mass balance simulation model of the environmental distribution food-chain accumulation of organic contaminants in aquatic ecosystems. The purpose of the model is to present a methodology for deriving maximum daily-loading estimates in accordance with environmental quality objectives for a variety of aquatic ecosystems impacted by emissions from one or several point or nonpoint sources. The application of the model to multiple, time-varying pulp and paper mill discharges of 2,3,7,8-tetrachlorodibenzo-p-dioxin and 2,3,7,8-tetrachlorodibenzofuran in the Fraser-Thompson River system from 1988 to 1995 is demonstrated. The ability of the model to predict chemical concentrations in various environmental media and organisms resulting from chemical emissions is tested against field data collected over a 7 year period. The results include (1) a comparison of observed and predicted concentrations, (2) an assessment of uncertainty, and (3) a test of the model`s temporal response to changes in contaminant loadings. The application of the model for the derivation of maximum daily loadings for multiple point sources in watersheds is illustrated.

  7. Synthesis and electrochemical properties of nonstoichiometric composition Li2.7Ti2(PO4)3/C with orthorhombic structure

    NASA Astrophysics Data System (ADS)

    Yao, Xiang; Su, Zhi; Pan, Hui

    2016-08-01

    Carbon-coated Li2.7Ti2(PO4)3, a new mixed-valence titanium(III/IV) phosphate, is synthesized by the microwave-assisted sol-gel method using citric acid as both a chelating reagent and carbon source for the cathode material in lithium-ion batteries. The contents of Li, Ti and P are analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES) and ion chromatography (IC). The microstructure, composition, and electrochemical performance of Li2.7Ti2(PO4)3/C samples are characterized by X-ray Diffraction (XRD), X-ray photoelectron spectroscopy(XPS), scanning electron microscope (SEM) and cyclic voltammetry (CV). The Li2.7Ti2(PO4)3/C sample exhibits a high initial discharge capacity of 123.6 mA h g-1 at 0.1C and outstanding cycling ability.

  8. Nicotine-morphine interactions at α4β2, α7 and α3(⁎) nicotinic acetylcholine receptors.

    PubMed

    Talka, Reeta; Salminen, Outi; Whiteaker, Paul; Lukas, Ronald J; Tuominen, Raimo K

    2013-02-15

    Nicotine and opioids share several behavioral and rewarding properties. Although both opioids and nicotine have their own specific mechanism of action, there is empirical and experimental evidence of interactions between these drugs. We studied receptor-level interactions of nicotine and morphine at α4β2, α7 and α3(⁎) nicotinic acetylcholine receptors. [(3)H]epibatidine displacement was used to determine if morphine binds competitively to nicotinic acetylcholine receptors. Functional interactions of morphine and nicotine were studied with calcium fluorometry and (86)Rb(+) efflux assays. Morphine displaced [(3)H]epibatidine from nicotinic agonist binding sites in all cell lines studied. The Ki values for morphine were 13.2μM in SH-EP1-hα4β2 cells, 0.16μM and 126μM in SH-SY5Y cells and 43.7μM in SH-EP1-hα7 cells. In SH-EP1-hα4β2 cells expressing α4β2 nicotinic acetylcholine receptors, morphine acted as a partial agonist of (86)Rb(+) efflux comparable to cytisine (with EC50 values of 53.3μM for morphine and 5.38μM for cytisine). The effect of morphine was attenuated concentration-dependently by the nicotinic antagonist mecamylamine. In the SH-SY5Y cell line expressing several subtypes of nicotinic acetylcholine receptors morphine had an inhibitory effect on nicotine induced (86)Rb(+) ion efflux mediated by α3(⁎) nicotinic acetylcholine receptors. These results suggest that morphine acts as a partial agonist at α4β2 nicotinic acetylcholine receptors and as a weak antagonist at α3(⁎) nicotinic acetylcholine receptors.

  9. THE KMOS{sup 3D} SURVEY: DESIGN, FIRST RESULTS, AND THE EVOLUTION OF GALAXY KINEMATICS FROM 0.7 ≤ z ≤ 2.7

    SciTech Connect

    Wisnioski, E.; Förster Schreiber, N. M.; Wuyts, S.; Wuyts, E.; Bandara, K.; Genzel, R.; Bender, R.; Davies, R.; Lang, P.; Mendel, J. T.; Beifiori, A.; Chan, J.; Fabricius, M.; Fudamoto, Y.; Kulkarni, S.; Kurk, J.; Lutz, D.; Wilman, D.; Fossati, M.; Brammer, G.; and others

    2015-02-01

    We present the KMOS{sup 3D} survey, a new integral field survey of over 600 galaxies at 0.7 < z < 2.7 using KMOS at the Very Large Telescope. The KMOS{sup 3D} survey utilizes synergies with multi-wavelength ground- and space-based surveys to trace the evolution of spatially resolved kinematics and star formation from a homogeneous sample over 5 Gyr of cosmic history. Targets, drawn from a mass-selected parent sample from the 3D-HST survey, cover the star formation-stellar mass (M {sub *}) and rest-frame (U – V) – M {sub *} planes uniformly. We describe the selection of targets, the observations, and the data reduction. In the first-year of data we detect Hα emission in 191 M {sub *} = 3 × 10{sup 9}-7 × 10{sup 11} M {sub ☉} galaxies at z = 0.7-1.1 and z = 1.9-2.7. In the current sample 83% of the resolved galaxies are rotation dominated, determined from a continuous velocity gradient and v {sub rot}/σ{sub 0} > 1, implying that the star-forming ''main sequence'' is primarily composed of rotating galaxies at both redshift regimes. When considering additional stricter criteria, the Hα kinematic maps indicate that at least ∼70% of the resolved galaxies are disk-like systems. Our high-quality KMOS data confirm the elevated velocity dispersions reported in previous integral field spectroscopy studies at z ≳ 0.7. For rotation-dominated disks, the average intrinsic velocity dispersion decreases by a factor of two from 50 km s{sup –1}at z ∼ 2.3 to 25 km s{sup –1}at z ∼ 0.9. Combined with existing results spanning z ∼ 0-3, we show that disk velocity dispersions follow an evolution that is consistent with the dependence of velocity dispersion on gas fractions predicted by marginally stable disk theory.

  10. Luminescence characteristics of C5+ ions and 60Co irradiated Li2BaP2O7:Dy3+ phosphor

    NASA Astrophysics Data System (ADS)

    Wani, J. A.; Dhoble, N. S.; Lochab, S. P.; Dhoble, S. J.

    2015-04-01

    In this work a study on some thermoluminescence characteristics of Li2BaP2O7:Dy phosphor is presented. The phosphor was synthesized by solid state diffusion method and characterized for its phase purity by X-ray diffraction (XRD). FT-IR spectrum was also carried out to confirm the presence of phosphate family and vibrations corresponding to P-O-P group. Spectroscopic investigation was approached through photoluminescence (PL) and thermoluminescence (TL). PL emission spectrum of Dy3+ ions corresponding to 4F9/2 → 6H13/2 (483 nm) and 4F9/2 → 6H15/2 (574 nm) transitions is revealed under 351 nm excitation wavelength. This characteristic emission confirms the presence of Dy3+ ions in the Li2BaP2O7 host matrix. To induce TL properties in Li2BaP2O7:Dy phosphor was irradiated with C5+ ion beams and gamma rays (60Co). A nearly simple glow curve was observed for Li2BaP2O7:Dy under two different excitation sources. TL response is almost linear over a wide range. Average absorbed dose (D bar) and mean linear energy transfer (LET ‾) of C5+ ion beams in Li2BaP2O7:Dy have also been calculated. Values of parameters like E and S known as trap depth and frequency factor respectively were obtained by using TLanal computer program. Also SRIM based calculations were performed to study the effect of C5+ ion beams on the samples of Li2BaP2O7:Dy. SRIM calculations show that Ba2+ vacancies are highest in number. Till date no such luminescence information on Li2BaP2O7:Dy phosphor is available.

  11. X-ray absorption study of the ferromagnetic Cu moment at the YBa2Cu3O7/La2 /3Ca1 /3MnO3 interface and variation of its exchange interaction with the Mn moment

    NASA Astrophysics Data System (ADS)

    Sen, K.; Perret, E.; Alberca, A.; Uribe-Laverde, M. A.; Marozau, I.; Yazdi-Rizi, M.; Mallett, B. P. P.; Marsik, P.; Piamonteze, C.; Khaydukov, Y.; Döbeli, M.; Keller, T.; Biškup, N.; Varela, M.; Vašátko, J.; Munzar, D.; Bernhard, C.

    2016-05-01

    With x-ray absorption spectroscopy and polarized neutron reflectometry we studied how the magnetic proximity effect at the interface between the cuprate high-TC superconductor YBa2Cu3O7 (YBCO) and the ferromagnet La2 /3Ca1 /3MnO3 (LCMO) is related to the electronic and magnetic properties of the LCMO layers. In particular, we explored how the magnitude of the ferromagnetic Cu moment on the YBCO side depends on the strength of the antiferromagnetic (AF) exchange coupling with the Mn moment on the LCMO side. We found that the Cu moment remains sizable if the AF coupling with the Mn moments is strongly reduced or even entirely suppressed. The ferromagnetic order of the Cu moments thus seems to be intrinsic to the interfacial CuO2 planes and related to a weakly ferromagnetic intraplanar exchange interaction. The latter is discussed in terms of the partial occupation of the Cu 3 d3 z2-r2 orbitals, which occurs in the context of the so-called orbital reconstruction of the interfacial Cu ions.

  12. Enhancement of the mechanoluminescence properties on Ca2MgSi2O7:Dy3+ phosphor by co-doping of charge compensator ions

    NASA Astrophysics Data System (ADS)

    Sahu, Ishwar Prasad

    2016-08-01

    In the present article, effect of charge compensator ions (R+ = Li+, Na+ and K+) on dysprosium-doped di-calcium magnesium di-silicate (Ca2MgSi2O7:Dy3+) phosphors were investigated. The Ca2MgSi2O7:Dy3+ and Ca2MgSi2O7:Dy3+, R+ phosphors, were prepared by solid-state reaction method. The crystal structures of sintered phosphors were an akermanite-type structure which belongs to the tetragonal crystallography. The peaks of mechanoluminescence (ML) intensity were increased linearly with increasing impact velocity of the moving piston. Thus, present investigation indicates that the piezoelectricity was responsible to produce ML in prepared phosphors. The time of the peak ML intensity and the decay rate did not change significantly with respect to increasing impact velocity. Addition of charge compensator ions enhances the luminescence intensity of prepared Ca2MgSi2O7:Dy3+ phosphors, because they neutralize the charge generated by Dy3+ substitution for Ca2+ ions. The role of Li+ ions among all charge compensator ions (Na+ or K+) used was found to be most effective for enhanced Dy3+ ion emission. These ML materials can be used in the devices such as stress sensor, fracture sensor, impact sensor, damage sensors, safety management monitoring system and fuse system for army warheads.

  13. Synthesis, characterization and photophysical properties of novel 5,7-disubstituted-1,4-diazepine-2,3-dicarbonitriles

    NASA Astrophysics Data System (ADS)

    Wieczorek, Ewelina; Gierszewski, Mateusz; Popenda, Lukasz; Tykarska, Ewa; Gdaniec, Maria; Jurga, Stefan; Sikorski, Marek; Mielcarek, Jadwiga; Piskorz, Jaroslaw; Goslinski, Tomasz

    2016-04-01

    Three 5,7-disubstituted-1,4-diazepine-2,3-dicarbonitriles with bulky 2-(3,5-dibromophenyl)ethenyl, 2-(4-tert-butylphenyl)ethenyl and 2-(3,5-dibenzyloxyphenyl)ethenyl substituents were synthesized and characterized using UV-Vis, MS ES, elemental analysis and NMR spectroscopy. NMR data indicated that diazepine rings of all obtained compounds adopted 6H-tautomeric form. In addition, trans-isomerism within styryl substituents was observed. Experimental data for diazepine derivative containing 2-(4-tert-butylphenyl)ethenyl substituents were verified by X-ray crystallography. The obtained compounds were subjected to photophysical studies. In the UV-Vis absorption spectra two characteristic bands were found. In the solvatochromic study, the first band maxima were located in the range of 384-418 nm, whereas second band maxima in the range of 313-345 nm. Fluorescence intensity of novel diazepine derivatives was rather low in all solvents used with the values of fluorescence quantum yield VF = 10-4 for 2-(3,5-dibromophenyl)ethenyl, and 10-5 for 2-(4-tert-butylphenyl)ethenyl and 3,5-(dibenzyloxyphenyl)ethenyl 1,4-diazepine-2,3-dicarbonitriles.

  14. Synthesis of polysubstituted 4,5,6,7-tetrahydrofuro[2,3-c]pyridines by a novel multicomponent reaction.

    PubMed

    Fayol, Aude; Zhu, Jieping

    2004-01-01

    [reaction: see text] A novel three-component synthesis of tetrahydrofuro[2,3-c]pyridines from readily accessible starting materials is described. Simply heating a toluene solution of an aminopentynoate, an aldehyde, and an alpha-isocyanoacetamide in the presence of ammonium chloride provided the 4,5,6,7-tetrahydrofuro[2,3-c]pyridines in good to excellent yield. The fused ring system is produced in this one-pot process by the concomitant formation of five chemical bonds. PMID:14703364

  15. DNA Strand Cleaving Properties and Hypoxia-Selective Cytotoxicity of 7-Chloro-2-thienylcarbonyl-3-trifluoromethylquinoxaline 1,4-Dioxide

    PubMed Central

    Junnotula, Venkatraman; Rajapakse, Anuruddha; Arbillaga, Leire; de Cerain, Adela López; Solano, Beatriz; Villar, Raquel; Monge, Antonio

    2012-01-01

    The heterocyclic N-oxide, 3-amino-1,2,4-benzotriazine 1,4-dioxide (tirapazamine, 1), shows promising antitumor activity in preclinical studies, but there is a continuing need to explore new compounds in this general structural category. In the work described here, we examined the properties of 7-chloro-2-thienylcarbonyl-3-trifluoromethylquinoxaline 1,4-dioxide (9h). We find that 9h causes redox-activated, hypoxia-selective DNA cleavage that mirrors the lead compound, tirapazamine, in both mechanism and potency. Furthermore, we find that 9h displays hypoxia-selective cytotoxicity against human cancer cell lines. PMID:20371184

  16. Grain size dependence of microwave absorption in Y 1Ba 2Cu 3O 7 powders near T c

    NASA Astrophysics Data System (ADS)

    Gould, A.; Jackson, E. M.; Renouard, K.; Crittenden, R.; Bhagat, S. M.; Spencer, N. D.; Dolhert, L. E.; Wormsbecher, R. F.

    1988-11-01

    A systematic study of the relationship between particle dimensions and microwave absorption in micron size powders of superconducting Y 1Ba 2Cu 3O 7 reveals that small particles have negligible absorption at T<0.8 Tc, and that the transition gets sharper as the grains get bigger. However, when the particles get so large as to incorporate multiple grains, the transition broadens and there is significant absorption down to 0.7 Tc. The temperature dependence in the small (≤10 μm) powders is satisfactorily described by a simple extension of London's theory.

  17. Thermal stability and 2.7 μm spectroscopic properties in Er3+ doped tellurite glasses

    NASA Astrophysics Data System (ADS)

    Tian, Ying; Li, Bingpeng; Chen, Rong; Xia, Jienan; Jing, Xufeng; Zhang, Junjie; Xu, Shiqing

    2016-10-01

    In present paper, the thermal stability and 2.7 μm spectroscopic properties in Er3+ doped tellurite glasses have been investigated by 980 nm laser diode pumping. Thermal analysis indicates that GeO2 modified tellurite glass has better thermal stability and anti-crystallization ability. Judd-Ofelt intensity parameters are calculated and discussed to examine the covalency characteristics based on absorption spectra. The 2.7 μm fluorescence is obtained and the lifetime can reach 124 ± 1 μs with the quantum efficiency of 61.5% in prepared samples. Moreover, higher effective emission bandwidth (136.67 nm), emission cross sections (12.75 × 10-21 cm2) and radiative transition probability (95.66s-1) at 2.7 μm are achieved. In addition, upconversion and near-infrared emission spectra are measured to elucidate energy transfer mechanism of Er3+. The results suggest that the present tellurite glass modified by GeO2 might have promising applications in mid-infrared fiber lasers.

  18. Dystonia and tremor following exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin

    SciTech Connect

    Klawans, H.L.

    1987-01-01

    Forty-seven railroad workers who were exposed to polychlorinated phenols, including dioxin (TCDD), during 1979 while cleaning up the chemical spillage following damage to a tank car filled with these chemicals were followed medically for the subsequent 6 years. Two committed suicide. The initial neurological complaints included a sense of fatigue and muscle aching, both of which have been reported in other individuals following dioxin exposure. On detailed neurological examination in December, 1985, 24 of 45 had dystonic writer's cramp and/or other action dystonias of the hands. None of the involved individuals had a family history of dystonia, and all 24 dated the onset of the dystonia to the first 2 to 3 years subsequent to their toxic exposure. The dystonias varied in severity but were usually mild. No other types of dystonic involvement were recognized. Thirty-five of the 45 individuals also manifested postural and terminal intention tremor which resembled benign essential tremor. None of the involved individuals had a family history of tremor, and all 35 of those affected dated the onset of the tremor to some time subsequent to their toxic exposure. Forty-three of 45 patients had histories and findings suggestive of peripheral neuropathy. This is the first report relating any type of dystonia to prior dioxin exposure and the first report relating action dystonia, such as dystonic writer's cramp, and postural/terminal intention tremor, to toxic exposure of any type.

  19. Extremely large anisotropic transport caused by electronic phase separation in Ti-doped Ca3Ru2O7

    NASA Astrophysics Data System (ADS)

    Peng, Jin; Liu, J. Y.; Gu, Xiaomin; Zhou, Guotai; Wang, Wei; Hu, J.; Zhang, F. M.; Wu, X. S.

    2016-06-01

    In this paper, we reported an extremely large out-of-plane/in-plane anisotropic transport ({ρc}/{ρab} ~ 109) in double layer ruthenates. The mechanism that may be responsible for this phenomenon is also explored here. Distinct from previously well studied layered materials which show large out-of-plane/in-plane electronic anisotropy (103–106), the Ti-doped Ca3Ru2O7 single crystals not only form quasi-2D layered structure, but also show phase separation within the layers. We found that Ti doping in Ca3Ru2O7 induced electronic phase separation between the insulating phase and weak localized phase. The ratio of these two phases is very sensitive to the Ti concentration. At typical concentration, the weak localized phase may form a channel on the background of the insulating phase within the ab plane. However, the small volume of weak localized phase makes it less likely to overlap in different layers. This results in a much larger electronic anisotropy ratio than pristine compound Ca3Ru2O7. This new mechanism provides a route for further increase electronic anisotropy, which will remarkably reduce current leak and power consumption in electronic devices.

  20. User's guide for ERB-7 SEFDT. Volume 3: Quality control report for year-2

    NASA Technical Reports Server (NTRS)

    Vasanth, K. L.

    1984-01-01

    Problems in the solar data generated by the Nimbus 7 satellite are discussed specifically for scientific users. Major and minor data flaws in the Solar and Earth Flux Data Tape (SEFDT) were identified, defined and categorized. Solar channel assembly misalignment, data gaps, and algorithm errors were among the problems described in detail. Solar flux density data derived from SEFDT are presented in graphical form.

  1. Reaction between enaminones and acetylenic esters in the presence of triphenylphosphine: a convenient synthesis of alkyl 2(1-benzyl-2,4-dioxo-2,3,4,5,6,7-hexahydro-1H-indol-3-yl)acetates.

    PubMed

    Nasiri, Farough; Bayzidi, Massood; Zolali, Amin

    2012-08-01

    One-pot reaction between enaminocarbonyl compounds derived from six-membered 1,3-diketones and substituted benzylamines, and electron-deficient acetylenic esters in the presence of triphenylphosphine lead to alkyl 2-(1-benzyl-6,6-dimethyl-2,4-dioxo-2,3,4,5,6,7-hexahydro-1H-indol-3-yl)acetate derivatives in good yields.

  2. Postnatal changes of nicotinic acetylcholine receptor alpha 2, alpha 3, alpha 4, alpha 7 and beta 2 subunits genes expression in rat brain.

    PubMed

    Zhang, X; Liu, C; Miao, H; Gong, Z H; Nordberg, A

    1998-10-01

    Postnatal changes of nicotinic acetylcholine receptor (nAChR) alpha 2, alpha 3, alpha 4, alpha 7 and beta 2 subunits mRNAs were investigated in rat brain using ribonuclease protection assay. Multiple developmental patterns were observed: (1) transient expression during the first few postnatal weeks; alpha 2 in the hippocampus and brain stem, alpha 3 in the striatum, cerebellum and cortex, alpha 4 in the hippocampus, striatum and cerebellum, alpha 7 in the cerebellum and beta 2 in the striatum. (2) Constant expression across development; alpha 2 and alpha 3 in the thalamus, alpha 4 in the cortex, thalamus and brain stem, alpha 7 in the thalamus and brain stem and beta 2 in all brain regions except striatum. (3) Non-detection across development; alpha 2 in the cortex, striatum and cerebellum. (4) Increase with age; alpha 7 in the cortex and hippocampus. (5) Bell-shaped development; alpha 7 in the striatum. Postnatal changes of nAChR isoforms in different brain regions of rat were investigated by receptor binding assays. The developmental patterns of [3H]epibatidine and (-)-[3H]nicotine binding sites were similar to each other in each brain region, but different from that of [3H] alpha-bungarotoxin binding sites. No obvious correlation was observed between the developmental patterns of [3H] alpha-bungarotoxin, [3H]epibatidine and (-)-[3H]nicotine binding sites and corresponding subunits mRNAs. These results indicate that multiple mechanisms are involved in changes of gene expression of nAChRs subunits in the brain of developing rats.

  3. Microstructure and flux pinning properties of melt textured grown doped YBa 2Cu 3O 7

    NASA Astrophysics Data System (ADS)

    Monot, I.; Verbist, K.; Hervieu, M.; Laffez, P.; Delamare, M. P.; Wang, J.; Desgardin, G.; Van Tendeloo, G.

    1997-02-01

    The physical properties and the microstructure of highly textured YBa 2Cu 3O 7/Y 2BaCuO 5 ceramics, doped with platinum and/or cerium have been investigated by high resolution electron microscopy (HREM), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The Ce, Pt and Ce + Pt doped samples show different Jc behaviours as function of the applied field and a systematic comparison of the microstructure at different scales has been performed. The combination of both dopants leads to a drastic improvement of the critical current density either under zero field or with an external magnetic field (fishtail effect). A critical current density up to 56 000 A/cm 2 has been observed, which remains 43 000 A/cm 2 under 1 T in a sample doped with 2 wt% cerium oxide and 0.5 wt% platinum oxide. We suggest that a slight introduction of Ce in the YBa 2Cu 3O 7-δ matrix locally changes the superconducting properties, and enhances the flux pinning properties. Micron size BaCeO 3 particles, which appear with a preferential orientation in the YBa 2Cu 3O 7-δ matrix, are also potential candidates for strong pinning. Other secondary phases, formed during the growth and the presence of a nanocrystalline phase in the plate like gap of the Ce + Pt doped samples are other admixtures. Finally a high density of twins is observed in all samples with some differences between the cerium and the platinum doped samples. They most probably contribute to pinning under intermediate field.

  4. Turtle sex determination assay: Mass balance and responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin and 3,3',4,4',5-pentachlorobiphenyl

    USGS Publications Warehouse

    Gale, Robert W.; Bergeron, Judith M.; Willingham, Emily J.; Crews, David

    2002-01-01

    Polyhalogenated hydrocarbons have been implicated in the anomalous sexual differentiation of mammals and reptiles. Here, a temperature-sensitive turtle sex determination assay using the red-eared slider (Trachemys scripta elegans) was used to determine the estrogenic or antiestrogenic activity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 3,3′,4,4′,5-pentachlorobiphenyl (PCB-126). Neither TCDD nor PCB-126 showed a statistically significant difference in the resulting sex ratios (Fisher's exact test, p < 0.45). As a consequence of the dosing technique (eggshell spotting), the shell retained 90 and 96% of the dose for PCB-126 and TCDD, respectively, similar to retention of estradiol-17β. However, the dosing allowed transfer of sufficient chemical to achieve tissue concentrations that were greater than most concentrations reported for environmentally incurred residues. Similar relative mass distributions of PCB-126 and TCDD were observed in albumin (14–20%), yolk (55–70%), and embryo (16–25%). Relative concentration distributions in the embryo approached those in the yolk, 37 to 40% and 40 to 52%, respectively, while relative concentrations in the albumin remained at 11 to 20%. Lipid-normalized TCDD and PCB-126 concentrations were 30- to 40-fold greater in the embryo than in the yolk. It is hypothesized that nonpassive partitioning processes may have occurred in the embryo.

  5. Thermodynamic evidence for the Bose glass transition in twinnedYBa2Cu3O7-δcrystals

    DOE PAGES

    Pérez-Morelo, D. J.; Osquiguil, E.; Kolton, A. B.; Nieva, G.; Jung, I. W.; López, D.; Pastoriza, H.

    2015-07-21

    We used a micromechanical torsional oscillator to measure the magnetic response of a twinned YBaBa2Cu3O7-δ single crystal disk near the Bose glass transition. We observe an anomaly in the temperature dependence of the magnetization consistent with the appearance of a magnetic shielding perpendicular to the correlated pinning of the twin boundaries. This effect is related to the thermodynamic transition from the vortex liquid phase to a Bose glass state.

  6. A series of new infrared NLO semiconductors, ZnY6Si2S14, Al(x)Dy3(Si(y)Al(1-y))S7, and Al0.33Sm3SiS7.

    PubMed

    Guo, Sheng-Ping; Guo, Guo-Cong; Wang, Ming-Sheng; Zou, Jian-Ping; Xu, Gang; Wang, Guo-Jian; Long, Xi-Fa; Huang, Jin-Shun

    2009-08-01

    Four new quaternary isostructural rare-earth thiosilicates, ZnY(6)Si(2)S(14) (1), Al(0.50)Dy(3)(Si(0.50)Al(0.50))S(7) (2), Al(0.38)Dy(3)(Si(0.85)Al(0.15))S(7) (3), and Al(0.33)Sm(3)SiS(7) (4), crystallized in the chiral and polar space group P6(3), have been prepared by a facile synthetic routine. Compounds 1-3 show strong second harmonic generation effects at 2.1 um with the intensities of 1, 2, and 3 being about 2, 2, and 1 times that of KTP (KTiOPO(4)), respectively. The calculated band structure of 1 implies that the optical absorptions of BLn(6)M(2)Q(14) and ALn(3)MQ(7) family compounds are mainly ascribed to the charge transitions from Q-p to Ln-4f (4d for Y) states. Compounds 2-4 exhibit antiferromagnetic-like interactions.

  7. Optimization of large area YBa 2Cu 3O 7-x films by single target ion beam sputtering

    NASA Astrophysics Data System (ADS)

    Gauzzi, A.; Lucia, M. L.; Affronte, M.; Pavuna, D.

    1991-12-01

    We report on the in-situ growth over large area of high-quality homogeneous YBa 2Cu 3O 7-x films by single target ion beam sputtering. The ‘123’ stoichiometry transfer to the substrates is obtained by using sufficiently low power ion beam and a grazing angle between the ion beam and the target. The as-deposited films show consistent homogeneity and reproducible superconducting properties (ΔT c<1 K, j c(77K)>10 6 A cm -2 at 77 K) over areas larger than ≈30 cm 2.

  8. Fabrication and characterization of La2Zr2O7 films on different buffer architectures for YBa2Cu3O7-δ coated conductors by RF magnetron sputtering.

    PubMed

    Xu, Da; Liu, Linfei; Xiao, Guina; Li, Yijie

    2013-02-27

    La2Zr2O7 (LZO) films were grown on different buffer architectures by radio frequency magnetron sputtering for the large-scale application of YBa2Cu3O7-x (YBCO)-coated conductors. The three different buffer architectures were cerium oxide (CeO2), yttria-stabilized zirconia (YSZ)/CeO2, and CeO2/YSZ/CeO2. The microstructure and surface morphology of the LZO film were studied by X-ray diffraction, optical microscopy, field emission scanning electron microscopy, and atomic force microscopy. The LZO films prepared on the CeO2, YSZ/CeO2, and CeO2/YSZ/CeO2 buffer architectures were preferentially c-axis-oriented and highly textured. The in-plane texture of LZO film on CeO2 single-buffer architecture was ∆ φ = 5.5° and the out-of-plane texture was ∆ ω = 3.4°. All the LZO films had very smooth surfaces, but LZO films grown on YSZ/CeO2 and CeO2/YSZ/CeO2 buffer architectures had cracks. The highly textured LZO film grown on CeO2-seed buffered NiW tape was suitable for the epitaxial growth of YBCO film with high currents.

  9. High trapped field performances in thin-wall YBa2Cu3O7-δ bulk cryomagnets

    NASA Astrophysics Data System (ADS)

    Kenfaui, Driss; Sibeud, Pierre-Frédéric; Louradour, Eric; Noudem, Jacques G.; Chaud, Xavier

    2013-05-01

    Thin-wall YBa2Cu3O7-δ bulk single domains were grown from drilled preforms with a holes network in the aim of increasing the specific areas and diminishing the oxygen diffusion paths. By applying a progressive annealing at high temperature under oxygen pressure (10 MPa), crack-free superconductors were obtained in a very short time (less than 3 days). A crack-free microstructure fostered large size persistent current loops, which boosted the trapped field performances. A trapped field Bmax = 5.2 T at 17 K was achieved on a 16 mm-diameter thin-wall pellet (disk surface s = 1.987 cm2), which led to a striking trapped field density Bmax/S=2.617 T cm-2.

  10. Directly coupled direct current superconducting quantum interference device magnetometers based on ramp-edge Ag:YBa{sub 2}Cu{sub 3}O{sub 7{minus}x}/PrBa{sub 2}Cu{sub 3}O{sub 7{minus}x}/Ag:YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} junctions

    SciTech Connect

    Jia, Q.X.; Yan, F.; Mombourquette, C.; Reagor, D.

    1998-06-01

    Directly coupled dc superconducting quantum interference device (SQUID) magnetometers on LaAlO{sub 3} substrates were fabricated using ramp-edge superconductor/normal-metal/superconductor junctions, where Ag-doped YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} was used for the electrode and PrBa{sub 2}Cu{sub 3}O{sub 7{minus}x} for the normal-metal barrier. A flux noise of 8{times}10{sup {minus}6}thinsp{Phi}{sub 0}thinspHz{sup {minus}1/2} at 10 kHz measured with a dc bias current was achieved at 75 K, which corresponded to a field sensitivity of 400thinspfTHz{sup {minus}1/2} for a magnetometer with a pick-up loop area of 8.5thinspmm{times}7.5thinspmm. Most significantly, the noise floor increased at lower frequencies with a frequency dependence slightly less than 1/f. The field noise of the SQUID magnetometers increased by only 25{percent} after cycling the devices from zero field to 500 mG. In a static earth{close_quote}s magnetic field background, the field noise of the SQUID magnetometers increased by less than a factor of 2. {copyright} {ital 1998 American Institute of Physics.}

  11. 7 CFR 7.2 - General.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false General. 7.2 Section 7.2 Agriculture Office of the Secretary of Agriculture SELECTION AND FUNCTIONS OF AGRICULTURAL STABILIZATION AND CONSERVATION STATE, COUNTY AND COMMUNITY COMMITTEES § 7.2 General. State, county, and community committees shall, as...

  12. Effect of surface coating of KYb2F7:Tm(3+) on optical properties and biomedical applications.

    PubMed

    Pedraza, Francisco J; Avalos, Julio C; Yust, Brian G; Tsin, Andrew; Sardar, Dhiraj K

    2016-09-23

    This project aims to provide an insight on the effects of biocompatible polymers on the optical properties and the nanoparticle-cell interaction of KYb2F7:Tm(3+) nanocrystals that exhibit strong near infrared (NIR) fluorescence. KYb2F7:Tm(3+) nanocrystals were synthesized with a diameter of 20-30 nm and surface modified with poly(ethylene glycol), Pluronic(®) F-127, and poly(N-vinylpyrrolidone), due to the associated advantages. Some of these include biocompatibility and biodistribution in the instance of agglomeration and hydrophobicity as well as the addition of a targeting agent and drug loading by further functionalization. Despite the decrease in fluorescence intensity induced by the surface modification, thulium's emission fingerprint was easily detected. Moreover, surface modified KYb2F7:Tm(3+) nanocrystals failed to induce a toxic response on endothelial cells following a 24 h uptake period up to concentrations of 100 μg ml(-1). In vitro toxicity and confocal imaging have demonstrated the versatility of these NIR fluorescence nanocrystals in biomedical imaging, drug delivery, and photodynamic therapy. PMID:27518385

  13. Effect of surface coating of KYb2F7:Tm3+ on optical properties and biomedical applications

    NASA Astrophysics Data System (ADS)

    Pedraza, Francisco J.; Avalos, Julio C.; Yust, Brian G.; Tsin, Andrew; Sardar, Dhiraj K.

    2016-09-01

    This project aims to provide an insight on the effects of biocompatible polymers on the optical properties and the nanoparticle-cell interaction of KYb2F7:Tm3+ nanocrystals that exhibit strong near infrared (NIR) fluorescence. KYb2F7:Tm3+ nanocrystals were synthesized with a diameter of 20–30 nm and surface modified with poly(ethylene glycol), Pluronic® F-127, and poly(N-vinylpyrrolidone), due to the associated advantages. Some of these include biocompatibility and biodistribution in the instance of agglomeration and hydrophobicity as well as the addition of a targeting agent and drug loading by further functionalization. Despite the decrease in fluorescence intensity induced by the surface modification, thulium’s emission fingerprint was easily detected. Moreover, surface modified KYb2F7:Tm3+ nanocrystals failed to induce a toxic response on endothelial cells following a 24 h uptake period up to concentrations of 100 μg ml‑1. In vitro toxicity and confocal imaging have demonstrated the versatility of these NIR fluorescence nanocrystals in biomedical imaging, drug delivery, and photodynamic therapy.

  14. Effect of surface coating of KYb2F7:Tm3+ on optical properties and biomedical applications

    PubMed Central

    Pedraza, Francisco J; Avalos, Julio C; Yust, Brian G; Tsin, Andrew; Sardar, Dhiraj K

    2016-01-01

    This project aims to provide an insight on the effects of biocompatible polymers on the optical properties and the nanoparticle-cell interaction of KYb2F7:Tm3+ nanocrystals that exhibit strong near infrared (NIR) fluorescence. KYb2F7:Tm3+ nanocrystals were synthesized with a diameter of 20–30 nm and surface modified with poly(ethylene glycol), Pluronic® F-127, and poly(N-vinylpyrrolidone), due to the associated advantages. Some of these include biocompatibility and biodistribution in the instance of agglomeration and hydrophobicity as well as the addition of a targeting agent and drug loading by further functionalization. Despite the decrease in fluorescence intensity induced by the surface modification, thulium’s emission fingerprint was easily detected. Moreover, surface modified KYb2F7:Tm3+ nanocrystals failed to induce a toxic response on endothelial cells following a 24 h uptake period up to concentrations of 100 μg ml−1. In vitro toxicity and confocal imaging have demonstrated the versatility of these NIR fluorescence nanocrystals in biomedical imaging, drug delivery, and photodynamic therapy. PMID:27518385

  15. Current dependent angular magnetoresistance in strongly Pr-doped Y Ba2Cu3O7-δ single crystal

    NASA Astrophysics Data System (ADS)

    Sandu, V.; Gyawali, P.; Katuwal, T.; Almasan, C. C.; Taylor, B. J.; Maple, M. B.

    2009-03-01

    We report a strong dependence of the angular magnetoresistance (AMR) on the current density in Y Ba2Cu3O7-δ single crystal above the critical temperature Tc = 13 K for any applied field up to 14 T. We estimated the current dependence from the angular dependence of the top resistance Rtop, as measured on the face where the current is applied, and the bottom resistance Rbot as measured on the opposite face. At any temperature, both below and above Tc, Rtop decreases as the field becomes parallel to the current and ab-plane with an angle dependence that suggests an important contribution arising from the vortex flow. Rbot evolves from a monotonic to nonmonotonic angle dependence with three minima and two maxima in the angle range 0 — 180° as the temperature increases. For less Pr-doped samples, Y0.58Pr0.42Ba2Cu3O7-δ (Tc = 39 K) and Y0.68rP0.32Ba2Cu3O7-δ (Tc = 55 K), where the interplane resistivity is much lower, both Rtop and Rbot follow the same monotonic angle dependence in all temperature and field range.

  16. Subtle porosity variation in the YBa2Cu3O(7-x) high-temperature superconductor revealed by ultrasonic imaging

    NASA Technical Reports Server (NTRS)

    Roth, D. J.; Generazio, E. R.; Stang, D. B.; Hepp, A. F.

    1990-01-01

    The characterization of global porosity variation within a nominally 93-percent-dense specimen of YBa2Cu3O(7-x) high-temperature superconductor is reported. With a computer-controlled scanning system, precision ultrasonic velocity measurements were obtained at 100 micron increments over an 8- by 8-mm area of the YBa2Cu3O(7-x) specimen. The measurements were used to form a color map of velocity variation across the scanned region of the specimen. Subtle velocity variation on the order of 1 percent was observed. The specimen was shown by experimental methods to be single-phase, untextured, and free of nonuniform residual microstresses. From this knowledge and an established velocity-density relationship, a likely conclusion is that the observed velocity variations are solely due to porosity variations of similar magnitude. Locating these subtle porosity variations is critical since they can result in an order of magnitude variation in J(sub c) for dense YBCO specimens. Thus, mapping the global porosity distribution within YBa2Cu3O(7-x) may reveal regions that have poorer superconducting properties. Ultrasonic velocity results are translated into useful microstructural information for the material scientist.

  17. Effect of surface coating of KYb2F7:Tm3+ on optical properties and biomedical applications

    NASA Astrophysics Data System (ADS)

    Pedraza, Francisco J.; Avalos, Julio C.; Yust, Brian G.; Tsin, Andrew; Sardar, Dhiraj K.

    2016-09-01

    This project aims to provide an insight on the effects of biocompatible polymers on the optical properties and the nanoparticle-cell interaction of KYb2F7:Tm3+ nanocrystals that exhibit strong near infrared (NIR) fluorescence. KYb2F7:Tm3+ nanocrystals were synthesized with a diameter of 20-30 nm and surface modified with poly(ethylene glycol), Pluronic® F-127, and poly(N-vinylpyrrolidone), due to the associated advantages. Some of these include biocompatibility and biodistribution in the instance of agglomeration and hydrophobicity as well as the addition of a targeting agent and drug loading by further functionalization. Despite the decrease in fluorescence intensity induced by the surface modification, thulium’s emission fingerprint was easily detected. Moreover, surface modified KYb2F7:Tm3+ nanocrystals failed to induce a toxic response on endothelial cells following a 24 h uptake period up to concentrations of 100 μg ml-1. In vitro toxicity and confocal imaging have demonstrated the versatility of these NIR fluorescence nanocrystals in biomedical imaging, drug delivery, and photodynamic therapy.

  18. 2,3,4,7,8-pentachlorodibenzofuran is a more potent cytochrome P4501A inducer than 2,3,7,8-tetrachlorodibenzo-p-dioxin in herring gull hepatocyte cultures.

    PubMed

    Hervé, Jessica C; Crump, Doug L D; McLaren, Kristina K; Giesy, John P; Zwiernik, Matthew J; Bursian, Steven J; Kennedy, Sean W

    2010-09-01

    Concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), and 2,3,7,8-tetrachlorodibenzofuran (TCDF) on cytochrome P4501A (CYP1A) induction were determined in primary cultures of embryonic herring gull (Larus argentatus) hepatocytes exposed for 24 h. Based on the concentration that induced 50% of the maximal response (EC50), the relative potencies of TCDD and TCDF did not differ by more than 3.5-fold. However, also based on the EC50, PeCDF was 40-fold, 21-fold, and 9.8-fold more potent for inducing ethoxyresorufin-O-deethylase (EROD) activity, CYP1A4 mRNA expression, and CYP1A5 mRNA expression than TCDD, respectively. The relative CYP1A-inducing potencies of PeCDF and of other dioxin-like chemicals (DLCs) in herring gull hepatocytes (HEH RePs), along with data on concentrations of DLCs in Great Lakes herring gull eggs, were used to calculate World Health Organization toxic equivalent (WHO-TEQ) concentrations and herring gull embryonic hepatocyte toxic equivalent (HEH-TEQ) concentrations. The analysis indicated that, when using avian toxic equivalency factors (TEFs) recommended by the WHO, the relative contribution of TCDD (1.1-10.2%) to total WHO-TEQ concentration was higher than that of PeCDF (1.7-2.9%). These results differ from the relative contribution of TCDD and PeCDF when HEH RePs were used; PeCDF was a major contributor (36.5-52.9%) to total HEH-TEQ concentrations, whereas the contribution by TCDD (1.2-10.3%) was less than that of PeCDF. The WHO TEFs for avian species were largely derived from studies with the domestic chicken (Gallus gallus domesticus). The findings of the present study suggest that it is necessary to determine the relative potencies of DLCs in wild birds and to re-evaluate their relative contributions to the biochemical and toxic effects previously reported in herring gulls and other avian species.

  19. A new group of aromatic prenyltransferases in fungi, catalyzing a 2,7-dihydroxynaphthalene 3-dimethylallyl-transferase reaction.

    PubMed

    Haug-Schifferdecker, Elisa; Arican, Deniz; Brückner, Reinhard; Heide, Lutz

    2010-05-28

    Five fungal genomes from the Ascomycota (sac fungi) were found to contain a gene with sequence similarity to a recently discovered small group of bacterial prenyltransferases that catalyze the C-prenylation of aromatic substrates in secondary metabolism. The genes from Aspergillus terreus NIH2624, Botryotinia fuckeliana B05.10 and Sclerotinia sclerotiorum 1980 were expressed in Escherichia coli, and the resulting His(8)-tagged proteins were purified and investigated biochemically. Their substrate specificity was found to be different from that of any other prenyltransferase investigated previously. Using 2,7-dihydroxynaphthalene (2,7-DHN) and dimethylallyl diphosphate as substrates, they catalyzed a regiospecific Friedel-Crafts alkylation of 2,7-DHN at position 3. Using the enzyme of A. terreus, the K(m) values for 2,7-DHN and dimethylallyl diphosphate were determined as 324 +/- 25 microM and 325 +/- 35 microM, respectively, and k(cat) as 0.026 +/- 0.001 s(-1). A significantly lower level of prenylation activity was found using dihydrophenazine-1-carboxylic acid as aromatic substrate, and only traces of products were detected with aspulvinone E, flaviolin, or 4-hydroxybenzoic acid. No product was formed with l-tryptophan, l-tyrosine, or 4-hydroxyphenylpyruvate. The genes for these fungal prenyltransferases are not located within recognizable secondary metabolic gene clusters. Their physiological function is yet unknown.

  20. Transport properties of La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/YBa{sub 2}Cu{sub 3}O{sub 7-δ} (LSMO/YBCO) heterostructure

    SciTech Connect

    Sharma, Minaxi; Sharma, K. K. E-mail: kknitham@gmail.com; Kumar, Arvind; Kumar, Ravi; Choudhary, R. J.

    2015-05-15

    We report on the transport properties of La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (200 nm)/YBa{sub 2}Cu3O{sub 7-δ} (50 nm) (LSMO/YBCO) heterostructure in the presence and absence of magnetic field, deposited on LaAlO3 (001) substrate using pulsed laser deposition technique. X- ray diffraction pattern confirms that the grown heterostructure is single phase in nature. The temperature dependent resistivity shows a metallic behavior below 304 K, superconductivity is completely suppressed by the presence of thick LSMO layer. From resistivity-temperature (ρ-T) curve, we have also observed the metal to insulator transition temperature at 304 K and increases to higher temperature side (353 K) on the application of magnetic field. We found a maximum magnetoresistance ratio ∼47% at 246 K temperature. Temperature co-efficient of resistance is ∼1.7 % K{sup −1} at 202 K, can be useful for bolometric performances and temperature sensors.

  1. NLRP3 inflammasome as a target of berberine in experimental murine liver injury: interference with P2X7 signalling.

    PubMed

    Vivoli, Elisa; Cappon, Andrea; Milani, Stefano; Piombanti, Benedetta; Provenzano, Angela; Novo, Erica; Masi, Alessio; Navari, Nadia; Narducci, Roberto; Mannaioni, Guido; Moneti, Gloriano; Oliveira, Claudia P; Parola, Maurizio; Marra, Fabio

    2016-10-01

    Berberine (BRB) is commonly used in herbal medicine, but its mechanisms of action are poorly understood. In the present study, we tested BRB in steatohepatitis induced by a methionine- and choline-deficient (MCD) diet, in acute acetaminophen intoxication and in cultured murine macrophages. BRB markedly improved parameters of liver injury and necroinflammation induced by the MCD diet, although increased mortality was observed by mechanisms independent of bacterial infections or plasma levels of BRB. The MCD diet induced up-regulation of all components of the NLRP3 (NACHT, LRR and PYD domain-containing protein 3) inflammasome, and increased hepatic levels of mature IL-1β (interleukin 1β). All of these parameters were significantly reduced in mice treated with BRB. In mice administered an acetaminophen overdose, a model dependent on inflammasome activation, BRB reduced mortality and ALT (alanine aminotransferase) elevation, and limited the expression of inflammasome components. In vitro, LPS (lipopolysaccharide)-induced activation of NLRP3 inflammasome in RAW264.7 murine macrophages was markedly decreased by pre-incubation with BRB. BRB significantly limited the activation of the purinergic receptor P2X7, involved in the late phases of inflammasome activation. Upon P2X7 knockdown, the ability of BRB to block LPS-induced secretion of IL-1β was lost. These data indicate that administration of BRB ameliorates inflammation and injury in two unrelated murine models of liver damage. We demonstrate for the first time that BRB interferes with activation of the NLRP3 inflammasome pathway in vivo and in vitro, through a mechanism based on interference with activation of P2X7, a purinergic receptor involved in inflammasome activation. PMID:27439970

  2. NLRP3 inflammasome as a target of berberine in experimental murine liver injury: interference with P2X7 signalling.

    PubMed

    Vivoli, Elisa; Cappon, Andrea; Milani, Stefano; Piombanti, Benedetta; Provenzano, Angela; Novo, Erica; Masi, Alessio; Navari, Nadia; Narducci, Roberto; Mannaioni, Guido; Moneti, Gloriano; Oliveira, Claudia P; Parola, Maurizio; Marra, Fabio

    2016-10-01

    Berberine (BRB) is commonly used in herbal medicine, but its mechanisms of action are poorly understood. In the present study, we tested BRB in steatohepatitis induced by a methionine- and choline-deficient (MCD) diet, in acute acetaminophen intoxication and in cultured murine macrophages. BRB markedly improved parameters of liver injury and necroinflammation induced by the MCD diet, although increased mortality was observed by mechanisms independent of bacterial infections or plasma levels of BRB. The MCD diet induced up-regulation of all components of the NLRP3 (NACHT, LRR and PYD domain-containing protein 3) inflammasome, and increased hepatic levels of mature IL-1β (interleukin 1β). All of these parameters were significantly reduced in mice treated with BRB. In mice administered an acetaminophen overdose, a model dependent on inflammasome activation, BRB reduced mortality and ALT (alanine aminotransferase) elevation, and limited the expression of inflammasome components. In vitro, LPS (lipopolysaccharide)-induced activation of NLRP3 inflammasome in RAW264.7 murine macrophages was markedly decreased by pre-incubation with BRB. BRB significantly limited the activation of the purinergic receptor P2X7, involved in the late phases of inflammasome activation. Upon P2X7 knockdown, the ability of BRB to block LPS-induced secretion of IL-1β was lost. These data indicate that administration of BRB ameliorates inflammation and injury in two unrelated murine models of liver damage. We demonstrate for the first time that BRB interferes with activation of the NLRP3 inflammasome pathway in vivo and in vitro, through a mechanism based on interference with activation of P2X7, a purinergic receptor involved in inflammasome activation.

  3. Nrf2 protects against 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced oxidative injury and steatohepatitis

    SciTech Connect

    Lu Hong; Cui Wei; Klaassen, Curtis D.

    2011-10-15

    Previous studies demonstrate that Nrf2, a master regulator of antioxidative responses, is essential in mediating induction of many antioxidative enzymes by acute activation of the AhR. However, the role of Nrf2 in protecting against oxidative stress and DNA damage induced by sustained activation of the AhR remains unknown and was investigated herein. Tissue and blood samples were collected from wild-type (WT) and Nrf2-null mice 21 days after administration of a low-toxic dose (10 {mu}g/kg ip) of TCDD. Only Nrf2-null mice lost body weight after TCDD treatment; however, blood levels of ALT were not markedly changed in either genotype, indicating a lack of extensive necrosis. Compared to livers of TCDD-treated WT mice, livers of TCDD-treated Nrf2-null mice had: 1) degenerated hepatocytes, lobular inflammation, marked fat accumulation, and higher mRNA expression of inflammatory and fibrotic genes; 2) depletion of glutathione, elevation in lipid peroxidation and marker of DNA damage; 3) attenuated induction of phase-II enzymes Nqo1, Gsta1/2, and Ugt2b35 mRNAs, but higher induction of cytoprotective Ho-1, Prdx1, Trxr1, Gclc, and Epxh1 mRNAs; 4) higher mRNA expression of Fgf21 and triglyceride-synthesis genes, but down-regulation of bile-acid-synthesis genes and cholesterol-efflux transporters; and 5) trend of induction/activation of c-jun and NF-kB. Additionally, TCDD-treated Nrf2-null mice had impaired adipogenesis in white adipose tissue. In conclusion, Nrf2 protects livers of mice against oxidative stress, DNA damage, and steatohepatitis induced by TCDD-mediated sustained activation of the AhR. The aggravated hepatosteatosis in TCDD-treated Nrf2-null mice is due to increased lipogenesis in liver and impaired lipogenesis in white adipose tissue. - Highlights: > TCDD causes hepatosteatosis and induction of Nrf2-target genes in wild-type mice. > TCDD causes weight loss, oxidative injury, and steatohepatitis in Nrf2-null mice. > Livers of TCDD-treated Nrf2-null mice have

  4. 2,3,4,7,8-Pentachlorodibenzofuran is far less potent than 2,3,7,8-tetrachlorodibenzo-p-dioxin in disrupting the pituitary–gonad axis of the rat fetus

    SciTech Connect

    Taura, Junki; Takeda, Tomoki; Fujii, Misaki; Hattori, Yukiko; Ishii, Yuji; Kuroki, Hiroaki; Tsukimori, Kiyomi; Uchi, Hiroshi; Furue, Masutaka; Yamada, Hideyuki

    2014-11-15

    The effect of 2,3,4,7,8-pentachlorodibenzofuran (PnCDF) on the fetal pituitary–gonad axis was compared with that produced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in Wistar rats. Maternal treatment at gestational day (GD) 15 with PnCDF and TCDD reduced the fetal expression at GD20 of pituitary luteinizing hormone (LH) and the testicular proteins necessary for steroidogenesis. The relative potencies of PnCDF ranged from 1/42nd to 1/63rd of the TCDD effect. While PnCDF, at a dose sufficient to cause a reduction in fetal LH, provoked defects in sexual behavior at adulthood, a dose less than the ED{sub 50} failed to produce any abnormality. There was a loss of fetal body weight following in utero exposure to PnCDF, and the effect of PnCDF was also much less than that of TCDD. The disturbance in fetal growth was suggested to be due to a reduction in the level of fetal growth hormone (GH) by dioxins. The disorder caused by PnCDF/TCDD in the fetal pituitary–gonad axis occurred at doses less than those needed to cause wasting syndrome in pubertal rats. The harmful effect of PnCDF relative to TCDD was more pronounced in fetal rats than in pubertal rats. These lines of evidence suggest that: 1) PnCDF as well as TCDD imprints defects in sexual behavior by disrupting the fetal pituitary–gonad axis; 2) these dioxins hinder fetal growth by reducing the expression of fetal GH; and 3) the fetal effects of PnCDF/TCDD are more sensitive than sub-acute toxicity during puberty, and the relative effect of PnCDF varies markedly depending on the indices used. - Highlights: • 2,3,4,7,8-Pentachlorodibenzofuran (PnCDF) lowers gonadal steroidogenesis in fetuses. • PnCDF exerts the above effect through an initial attenuation in gonadotropin level. • PnCDF imprints sexual immaturity by transiently disrupting the pituitary–gonad axis. • PnCDF also disturbs pup growth probably due to a reduction in growth hormone level. • The above effects are far lesser in PnCDF than 2,3,7

  5. Thermodynamic studies of studtite thermal decomposition pathways via amorphous intermediates UO3, U2O7, and UO4

    DOE PAGES

    Guo, Xiaofeng; Wu, Di; Xu, Hongwu; Burns, Peter C.; Navrotsky, Alexandra

    2016-06-08

    The thermal decomposition of studtite (UO2)O2(H2O)2·2H2O results in a series of intermediate X-ray amorphous materials with general composition UO3+x (x = 0, 0.5, 1). As an extension of a structural study on U2O7, this work provides detailed calorimetric data on these amorphous oxygen-rich materials since their energetics and thermal stability are unknown. These were characterized in situ by thermogravimetry, and mass spectrometry. Ex situ X-ray diffraction and infrared spectroscopy characterized their chemical bonding and local structures. This detailed characterization formed the basis for obtaining formation enthalpies by high temperature oxide melt solution calorimetry. The thermodynamic data demonstrate the metastability ofmore » the amorphous UO3+x materials, and explain their irreversible and spontaneous reactions to generate oxygen and form metaschoepite. Thus, formation of studtite in the nuclear fuel cycle, followed by heat treatment, can produce metastable amorphous UO3+x materials that pose the risk of significant O2 gas. Quantitative knowledge of the energy landscape of amorphous UO3+x was provided for stability analysis and assessment of conditions for decomposition.« less

  6. Thermodynamic studies of studtite thermal decomposition pathways via amorphous intermediates UO3, U2O7, and UO4

    NASA Astrophysics Data System (ADS)

    Guo, Xiaofeng; Wu, Di; Xu, Hongwu; Burns, Peter C.; Navrotsky, Alexandra

    2016-09-01

    The thermal decomposition of studtite (UO2)O2(H2O)2·2H2O results in a series of intermediate X-ray amorphous materials with general composition UO3+x (x = 0, 0.5, 1). As an extension of a structural study on U2O7, this work provides detailed calorimetric data on these amorphous oxygen-rich materials since their energetics and thermal stability are unknown. These were characterized in situ by thermogravimetry, and mass spectrometry. Ex situ X-ray diffraction and infrared spectroscopy characterized their chemical bonding and local structures. This detailed characterization formed the basis for obtaining formation enthalpies by high temperature oxide melt solution calorimetry. The thermodynamic data demonstrate the metastability of the amorphous UO3+x materials, and explain their irreversible and spontaneous reactions to generate oxygen and form metaschoepite. Thus, formation of studtite in the nuclear fuel cycle, followed by heat treatment, can produce metastable amorphous UO3+x materials that pose the risk of significant O2 gas. Quantitative knowledge of the energy landscape of amorphous UO3+x was provided for stability analysis and assessment of conditions for decomposition.

  7. Development of a superconducting joint between a GdBa2Cu3O7-δ-coated conductor and YBa2Cu3O7-δ bulk: towards a superconducting joint between RE (Rare Earth) Ba2Cu3O7-δ-coated conductors

    NASA Astrophysics Data System (ADS)

    Jin, Xinzhe; Yanagisawa, Yoshinori; Maeda, Hideaki; Takano, Yoshiki

    2015-07-01

    We have started to develop a superconducting bridge joint between two GdBa2Cu3O7-δ (Gd123)-coated conductors, where both conductors are placed in an end-to-end arrangement on the surface of a melt-textured YBCO (including Y2BaCuO5 and YBa2Cu3O7-δ) bulk, which acts as a superconducting medium between the coated conductors. As a first step in the development, one half of the bridge joint assembly was modeled and investigated. Experimental results achieved are as follows: (a) the higher-melting-temperature textured Gd123-coated conductor acts as a seed for the melt texture of the YBa2Cu3O7-δ (Y123) bulk, and (b) the superconducting phase continues across the Y123/Gd123 boundary. The critical current of the joint model is 10 A, which is about 10% of the original Gd123-coated conductor, at 77 K in a self-magnetic field. These results are considered to be extensible to the superconducting bridge joint between the Gd123-coated conductors.

  8. Room temperature degradation of YBa2Cu3O(7-x) superconductors in varying relative humidity environments

    NASA Technical Reports Server (NTRS)

    Hooker, M. W.; Wise, S. A.; Carlberg, I. A.; Stephens, R. M.; Simchick, R. T.; Farjami, A.

    1993-01-01

    An aging study was performed to determine the stability of YBa2Cu3O(7-x) ceramics in humid environments at 20 C. In this study, fired ceramic specimens were exposed to humidity levels ranging from 30.5 to 100 percent for 2-, 4-, and 6-week time intervals. After storage under these conditions, the specimens were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrical resistance measurements. At every storage condition evaluated, the fired ceramics were found to interact with H2O present in the surrounding environment, resulting in the decomposition of the YBa2Cu3O(7-x) phase. XRD data showed that BaCO3, CuO, and Y2BaCuO5 were present after aging and that the peak intensities of these impurity phases increased both with increasing humidity level and with increasing time of exposure. Additionally, SEM analyses of the ceramic microstructures after aging revealed the development of needle-like crystallites along the surface of the test specimens after aging. Furthermore, the superconducting transition temperature T(sub c) was found to decrease both with increasing humidity level and with increasing time of exposure. All the specimens aged at 30.5, 66, and 81 percent relative humidity exhibited superconducting transitions above 80 K, although these values were reduced by the exposure to the test conditions. Conversely, the specimens stored in direct contact with water (100 percent relative humidity) exhibited no superconducting transitions.

  9. The balance of TCF7L2 variants with differential activities in Wnt-signaling is regulated by lithium in a GSK3{beta}-independent manner

    SciTech Connect

    Struewing, Ian; Boyechko, Tania; Barnett, Corey; Beildeck, Marcy; Byers, Stephen W.; Mao, Catherine D.

    2010-08-20

    Research highlights: {yields} Identification of a novel effect of lithium on the expression of TCF7L2 RNA isoforms and protein variants. {yields} The extent of lithium-induced TCF7L2 form switch mirrors cell responsiveness to Wnt/{beta}-catenin signaling. {yields} Demonstration that lithium has dual GSK3{beta}-dependent and -independent effects on TCF7L2 expression. {yields} Demonstration that TCF7L2 expression is repressed by the transcriptionally active TCF7L2E form. {yields} Evidence for a lithium-induced de-repression mechanism of TCF7L2 expression via TCF7L2 variant switch. -- Abstract: TCF7L2 transcription factor is a downstream effector of the canonical Wnt/{beta}-catenin signaling, which controls cell fate and homeostasis. However, the complexity of TCF7L2 expression with numerous mRNA isoforms coding for proteins with distinct N- and C-termini allows variability in TCF7L2 functions and regulations. Here, we show that although TCF7L2 mRNA isoforms distinguish fetal, immortalized and adult differentiated endothelial cells (EC), they cannot explain the lack of significant {beta}-catenin/TCF7 activities in ECs. Lithium, a Wnt-signaling activator, increases TCF7L2 mRNA levels and induces an RNA isoform switch favoring the expression of TCF7L2-short forms lacking the C-termini domains. Although the latter occurs in different cell types, its extent depends on the overall increase of TCF7L2 transcription, which correlates with cell responsiveness to Wnt/{beta}-catenin signaling. While GSK3{beta} down-regulation increases TCF7L2 expression, there is no concomitant change in TCF7L2 mRNA isoforms, which demonstrate the dual effects of lithium on TCF7L2 expression via a GSK3{beta}-dependent up-regulation and a GSK3{beta}-independent modulation of RNA splicing. TCF7L2E-long forms display a repressor activity on TCF7L2-promoter reporters and lithium induces a decrease of the endogenous TCF7L2 forms bound to native TCF7L2-promoter chromatin at two novel distal TCF7

  10. Properties of large area ErBa2Cu3O(7-x) thin films deposited by ionized cluster beams

    NASA Technical Reports Server (NTRS)

    Levenson, L. L.; Stan, M.; Bhasin, K. B.

    1991-01-01

    Ionized cluster beam (ICB) deposition is employed to produce ErBa2Cu3O(7-x) films on different substrates without post-annealing. Films with diameters of up to 70 mm are grown on SrTiO3 100 plane and exhibit Tc values of 84-87 K, Jc of about 10 exp 6 A/sq m at 77 K. These films are epitaxial with the c-axis perpendicular to the plane of the substrate surface, and they can be routinely produced by ICB with good Jc and Tc.

  11. Reduced reactivity to air on HF-treated YBa2Cu3O(7-x)surfaces

    NASA Technical Reports Server (NTRS)

    Vasquez, R. P.; Hunt, B. D.; Foote, M. C.

    1989-01-01

    Treatment of YBa2Cu3O(7-x) films with a nonaqueous solution of HF in absolute ethanol results in the formation of an oxyfluoride with relative Y:Ba:Cu concentrations of 1:4:3 on the surface, as determined by X-ray photoelectron spectroscopy. The passivation properties of chemically treated films were tested by monitoring the growth of the high binding energy O 1s peak, associated with nonsuperconducting surface species, as a function of air exposure time, for both HF-treated and untreated films. The native oxyfluoride is shown to reduce the reactivity of the superconductor to air.

  12. Images of interlayer vortices and c -axis penetration depth of high- Tc YBa2Cu3O7-y superconductor

    NASA Astrophysics Data System (ADS)

    Iguchi, Ienari; Takeda, Tomohiro; Uchiyama, Tetsuji; Sugimoto, Akira; Hatano, Takeshi

    2006-06-01

    The measurements on the magnetic image of interlayer vortices are performed for the high- Tc YBa2Cu3O7-y(110) thin film using a high sensitive scanning SQUID microscopy. Clear images of aligned giant interlayer vortices are observable. For the majority of vortices, using the London model, the c -axis penetration depth is estimated to be about 20μm at 3K . The temperature dependence of λc is obtained from the observed vortex images at different temperatures, whose behavior is in good agreement with those of the microwave cavity measurement.

  13. Effect of thyroidectomy and thyroxine on 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced immunotoxicity

    SciTech Connect

    Pazdernik, T.L.; Rozman, K.K.

    1985-02-18

    Radiothyroidectomy protected against 2,3,7,8-tetrachloro dibenzo-p-dioxin (TCDD)-induced immunotoxicity in rats as assessed by the spleen anti-SRBC plaque-forming cell assay. Thyroxin (T/sub 4/) replacement therapy partially reversed the effects of thyroidectomy on T/sub 4/ and triiodothyronine (T/sub 3/) serum levels, body weight and immune function as well as restored TCDD-induced immunotoxicity. Thus, hypothyroidism induced by TCDD exposure can be viewed as a protective response of the organism to reduce the insult caused by TCDD.

  14. Deposition, surface chemistry, and electrochemistry of yttrium barium(2) copper(3) oxide(7-delta)

    NASA Astrophysics Data System (ADS)

    Wells, Andrea Dawn

    2001-10-01

    While high-temperature superconductors have been around for over 15 years, implementation of these materials into devices has been hindered by their poor materials properties. Work described in this dissertation targets the development of a fundamental understanding of the interfacial properties exhibited by common cuprate superconductors. This dissertation is organized such that the core introductory topics are covered in this chapter with more details provided in subsequent chapters as relevant. Chapter 2 covers the subject matter associated with the optimization of YBCO thin films created by pulsed laser deposition. Using an experimental design methodology, the laser energy, temperature and oxygen partial pressure are varied to create high quality c-axis oriented thin film. In addition, the temperature of a seed layer is varied with the deposition of a YBCO layer to create high quality a-axis films. These films are evaluated and characterized by their x-ray diffraction and resistivity versus temperature. The surface quality is evaluated by scanning electron microscopic imaging. Once these films are created, the electrochemistry on their surface is characterized. Chapter 3 of this dissertation uses electrochemical methods to determine the relationship between electrode response and surface corrosion. Here, XPS is also used to determine the surface quality of the films and the effectiveness of integration of a pulse laser ablation facility with a glove box to control surface corrosion. By comparing the XPS data with that obtained by the electrochemical responses, a more complete understanding of the surface chemistry and relative reactivity characteristics of YBCO films of different orientations is obtained. In addition, a-axis oriented grains are evaluated as are their c-axis counterparts to explore the capacity for both to support electrodeposition of silver upon the surface. These results are compared to those obtained on unoptimized corroded films treated by

  15. Structural changes and superconducting properties of Gd1-2xPrxCaxBa2Cu3O7-δ HTSCs

    NASA Astrophysics Data System (ADS)

    Udomkan, N.; Winotai, P.; Suryanarayanan, R.; Charoenthai, N.

    2005-10-01

    We report on structural changes and the properties of Gd1-2xPrxCaxBa2Cu3O7-δ (0<=x<=0.3) high temperature superconductors which were prepared and characterized. The transition temperature (Tc) was found to decrease roughly linearly with respect to the Pr and Ca concentration x. 65Cu2+(3d9) and 63Cu2+(3d9) ions from impurity phase BaCuO2 give rise to X-band electron spin resonant (ESR) two-quartet absorption peaks centred at ~310 mT (g~2.020) which are superposed by the broad ESR peak of Gd3+(4f7) at g~2.000 in the undoped Gd123. Both sets of ESR peaks shift towards low fields as the temperature is lowered, which is due to the change in crystal field experienced by the ions. It should be noted here that even at 77 K there still is no magnetic ordering from Gd3+ ions. However, at x = 0.025 doping, a new six-peak hyperfine multiplet ESR signal arising from 141Pr4+ (4f1,S = 1/2,I = 5/2) appears at ~323 mT (g~2.029). Typical simulated ESR parameters of Gd3+ in Gd1-2xPrxCaxBa2Cu3O7-δ at x = 0.025, are gx = 2.4879, gy = 2.3921 and gz = 2.2590, Axx = 12.50, Ayy = 23.50, Azz = 32.00 G and the zero-field splitting parameter (D) of 66.0 G, respectively. This signal arises from some Pr ions entering the Gd site with a valence of four, thus lending support to the hole-filling and pair-breaking models.

  16. On the entangled growth of NaTaO3 cubes and Na2Ti3O7 wires in sodium hydroxide solution.

    PubMed

    Baumann, Stefan O; Liu, Chang; Elser, Michael J; Sternig, Andreas; Siedl, Nicolas; Berger, Thomas; Diwald, Oliver

    2013-07-29

    The entangled growth of sodium titanate Na2Ti3O7 nanowires and sodium tantalate NaTaO3 cubes was investigated with electron microscopy, X-ray diffraction, and UV diffuse reflectance spectroscopy. Depending on the composition of the Ta2O5- and TiO2-particle-based powder mixtures, which served as educts, we observed different types of hybridization effects. These include the titanium-induced contraction of the NaTaO3 perovskite-type unit cell and the generation of electronic defect states in NaTaO3 that give rise to optical subbandgap transitions and tantalum-induced limitations of the Na2Ti3O7 nanowire growth. The transformation from Ta2O5 to NaTaO3 occurs through a dissolution-recrystallization process. A systematic analysis of the impact of different titanium sources on NaTaO3 dispersion and, thus, on the properties of the entangled nanostructures revealed that a perfect intermixture of cubes and nanowires can only be achieved when titanate nanosheets emerge during transformation as reaction intermediates and shield nucleation and growth of isolated NaTaO3 cubes. The here demonstrated approach can be highly instrumental for understanding the nucleation and growth of composite and entangled nanostructures in solution and--at the same time--provides an interesting new class of photoactive composite materials.

  17. In-plane electric field controlled perpendicular magnetic anisotropy in an FePt/[Pb(Mg1/3Nb2/3)O3]0.7-(PbTiO3)0.3 heterostructure

    NASA Astrophysics Data System (ADS)

    Guo, Qi; Xu, Xiaoguang; Feng, Julong; Liu, Pengfei; Wu, Yong; Ma, Li; Zhou, Shiming; Miao, Jun; Jiang, Yong

    2016-06-01

    We report the in-plane electric field controlled perpendicular magnetic anisotropy of L10-FePt films deposited on polarized [Pb(Mg1/3Nb2/3)O3]0.7-(PbTiO3)0.3 single crystal substrates. The out-of-plane coercivity (H c⊥) of FePt films exhibits a regular response to the in-plane electric field applied on substrates. The experimental change of H c⊥ is approximately 21.3% with the electric field varying from -10 to 10 kV/cm. The magnetization direction can be controlled by switching the electric field. The remanence of FePt films can also be manipulated by the electric field, so that a “W”-shaped sawtooth magnetic signal can be generated by a sawtooth electric field.

  18. 4-(8-Quinolyl)amino-7-nitro-2,1,3-benzoxadiazole as a new colorimetric probe for rapid and visual detection of Hg2+

    NASA Astrophysics Data System (ADS)

    Wang, Ke; Yang, Lixue; Zhao, Chuan; Ma, Huimin

    2013-03-01

    4-Amino-7-nitro-2,1,3-benzoxadiazole (ANBD) usually serves as a scaffold for developing fluorescent probes. In this paper, however, ANBD has been used as a chromogenic unit to design a new colorimetric probe, 4-(8-quinolyl)amino-7-nitro-2,1,3-benzoxadiazole (1), for rapid and visual detection of Hg2+. The reaction of 1 with Hg2+ in NaH2PO4-Na2HPO4 buffer (pH 7.0) containing 70% (v/v) acetonitrile forms a 1:1 complex, accompanying a red shift of the absorption maximum from 482 nm to 557 nm and a distinct color change from orange to violet. Moreover the color reaction exhibits a high selectivity and sensitivity to Hg2+ only, instead of other common metal ions. This behavior may be ascribed to the formation of a specific 1-Hg2+ complex, which is supported by 1H NMR titration experiments. The present study is not only a supplement to the detection method of Hg2+, but also a merit to the chemistry of 4-amino-7-nitro-2,1,3-benzoxadiazole.

  19. Cation disorder and gas phase equilibrium in an YBa 2Cu 3O 7- x superconducting thin film

    NASA Astrophysics Data System (ADS)

    Shin, Dong Chan; Ki Park, Yong; Park, Jong-Chul; Kang, Suk-Joong L.; Yong Yoon, Duk

    1997-02-01

    YBa 2Cu 3O 7- x superconducting thin films have been grown by in situ off-axis rf sputtering with varying oxygen pressure, Ba/Y ratio in a target, and deposition temperature. With decreasing oxygen pressure, increasing Ba/Y ratio, increasing deposition temperature, the critical temperature of the thin films decreased and the c-axis length increased. The property change of films with the variation of deposition variables has been explained by a gas phase equilibrium of the oxidation reaction of Ba and Y. Applying Le Chatelier's principle to the oxidation reaction, we were able to predict the relation of deposition variables and the resultant properties of thin films; the prediction was in good agreement with the experimental results. From the relation between the three deposition variables and gas phase equilibrium, a 3-dimensional processing diagram was introduced. This diagram has shown that the optimum deposition condition of YBa 2Cu 3O 7- x thin films is not a fixed point but can be varied. The gas phase equilibrium can also be applied to the explanation of previous results that good quality films were obtained at low deposition temperature using active species, such as O, O 3, and O 2+.

  20. Ligand binding to the human MT2 melatonin receptor: The role of residues in transmembrane domains 3, 6, and 7

    SciTech Connect

    Mazna, Petr; Berka, Karel; Balik, Ales; Svoboda, Petr; Obsilova, Veronika; Obsil, Tomas . E-mail: teisingr@biomed.cas.cz

    2005-07-08

    To better understand the mechanism of interactions between G-protein-coupled melatonin receptors and their ligands, our previously reported homology model of human MT2 receptor with docked 2-iodomelatonin was further refined and used to select residues within TM3, TM6, and TM7 potentially important for receptor-ligand interactions. Selected residues were mutated and radioligand-binding assay was used to test the binding affinities of hMT2 receptors transiently expressed in HEK293 cells. Our data demonstrate that residues N268 and A275 in TM6 as well as residues V291 and L295 in TM7 are essential for 2-iodomelatonin binding to the hMT2 receptor, while TM3 residues M120, G121, V124, and I125 may participate in binding of other receptor agonists and/or antagonists. Presented data also hint at possible specific interaction between the side-chain of Y188 in second extracellular loop and N-acetyl group of 2-iodomelatonin.

  1. 7 CFR Appendices 1, 2 and 3 to... - Dairy Tariff-Rate Import Quota Licensing

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Tokyo round Uruguay round NON-CHEESE ARTICLES BUTTER (NOTE 6) 5,278,428 1,698,572 EU-25 75,459 20,702... Uruguay 250,000 Other Countries 100,906 100,729 Any Country 300,000 BLUE-MOLD CHEESE (EXCEPT STILTON...,276 210,207 367,517 1,890,000 EU-25 2,496,468 885,532 2,025,000 Romania 500,000 Uruguay 428,000...

  2. Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on development of anuran amphibians

    SciTech Connect

    Jung, R.E.; Walker, M.K.

    1997-02-01

    The authors exposed anuran eggs and tadpoles to vehicle control (0.7% acetone) or waterborne [{sup 3}H]2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 24 h and subsequently raised them in clean water. Neither American toads nor green frogs exhibited TCDD-related mortality, but leopard frogs showed significantly increased mortality over controls. Eggs and tadpoles eliminated TCDD relatively quickly compared with published data for other vertebrates, with t{sub {1/2}} of 1 to 5 d (American toad), 2 to 7 d (leopard frog), and 4 to 6 d (green frog). Elimination rates were slowest for tadpoles fed nothing, fastest for those fed a low-fat diet, and intermediate for those fed a high-fat diet. Although not significant, American toads exposed to {ge}0.03 {micro}g TCDD/L appeared to metamorphose earlier, and those exposed to higher TCDD treatments appeared to metamorphose at a larger body mass than controls. Comparisons of these results with studies of fish early life stages suggest that anuran eggs and tadpoles eliminate TCDD more rapidly and are 100- to 1,000-fold less sensitive to its deleterious effects during development. These differences may be related to differences in metabolic rate, patterns of lipid storage and utilization, and aryl hydrocarbon receptor binding and signal transduction.

  3. Non-local spin injection effects in coplanar La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}/ La{sub 0.7}Sr{sub 0.3}MnO{sub 3} tri-layer

    SciTech Connect

    Joseph, D. Paul; Lin, J. G.

    2015-06-24

    Non-local electrical properties of pulsed laser deposited La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (L-B-L) coplanar tri-layer is investigated under different wiring configurations. Long range super-current of Bi-2212 penetrating into LSMO is dependent on geometry of spin injection. From qualitative analysis of structural, magnetic and electrical data, long range super-current is suggested to pass through domain walls and/or grain boundaries of LSMO.

  4. Caspase-3/7-mediated Cleavage of β2-spectrin is Required for Acetaminophen-induced Liver Damage

    PubMed Central

    Baek, Hye Jung; Lee, Yong Min; Kim, Tae Hyun; Kim, Joo-Young; Park, Eun Jung; Iwabuchi, Kuniyoshi; Mishra, Lopa; Kim, Sang Soo

    2016-01-01

    The ubiquitously expressed β2-spectrin (β2SP, SPTBN1) is the most common non-erythrocytic member of the β-spectrin gene family. Loss of β2-spectrin leads to defects in liver development, and its haploinsufficiency spontaneously leads to chronic liver disease and the eventual development of hepatocellular cancer. However, the specific role of β2-spectrin in liver homeostasis remains to be elucidated. Here, we reported that β2-spectrin was cleaved by caspase-3/7 upon treatment with acetaminophen which is the main cause of acute liver injury. Blockage of β2-spectrin cleavage robustly attenuated β2-spectrin-specific functions, including regulation of the cell cycle, apoptosis, and transcription. Cleaved fragments of β2-spectrin were physiologically active, and the N- and C-terminal fragments retained discrete interaction partners and activity in transcriptional regulation and apoptosis, respectively. Cleavage of β2-spectrin facilitated the redistribution of the resulting fragments under conditions of liver damage induced by acetaminophen. In contrast, downregulation of β2-spectrin led to resistance to acetaminophen-induced cytotoxicity, and its insufficiency in the liver promoted suppression of acetaminophen-induced liver damage and enhancement of liver regeneration. Conclusions: β2-Spectrin, a TGF-β mediator and signaling molecule, is cleaved and activated by caspase-3/7, consequently enhancing apoptosis and transcriptional control to determine cell fate upon liver damage. These findings have extended our knowledge on the spectrum of β2-spectrin functions from a scaffolding protein to a target and transmitter of TGF-β in liver damage. PMID:26884715

  5. Toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin to embryos of the fathead minnow (Pimephales promelas, Rafinesque)

    SciTech Connect

    Olivieri, C.; Cooper, K.

    1995-12-31

    This study correlates the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) residue and its toxicity to the fathead minnow embryo exposed to levels lower than the TCDD solubility range. The TCDD tissue doses in the embryo/larvae were related to gross lesions, delayed hatching, and death. A 7-day bioconcentration factor on a lipid basis (BCF{sub L}) was calculated. Embryos at the blatsula stage were exposed to [{sup 3}H] TCDD water concentrations (0.37, 0.59, 1.2, 2.83, and 10.1 6 ng/L), a nontreatment control and a solvent carrier control. Lesions were qualified as mild and severe based on their onset and their pathogenesis. Thus, mild lesions developed just prior to hatching or post-hatching at the fifth day of development. The severe lesions appeared at the third day of development. Embryos with tissue doses {le}2.46 {+-} 1.34 ng/g consistently developed mild lesions, while embryos with tissue doses {ge} 12.07 {+-} 4.91 ng/g developed severe lesions. The lowest observable adverse effect level was 0.04 {+-} 0.02 ng/g. The calculated 7-day ED{sub 50} was 0.14 ng/g. There was no delayed hatching at any of the concentrations tested. Embryo death occurred at a tissue concentration {ge}2.46 ng/g. The calculated 7-day LD{sub 50} was 25.71 ng/g. The relationship between the concentration of TCDD in the water (x = ng/L) and in the tissue dose (y = ng/g) fitted a linear curve y = {minus}1,143 + 3,792.5x, r{sup 2} = 0.98. The calculated BCF{sub L} (wet weight) was dose dependent. Embryos with tissue doses of 0.04 and 0.16 ng/g had BCF{sub L} of 2,700 and 3,325, respectively. Embryos with tissue doses of 2.46, 12.07, and 37.07 ng/g, had a BCF{sub L} of 104,225, 106,625 and 91,075, respectively.

  6. Observation of a three-dimensional quasi-long-range electronic supermodulation in YBa2Cu3O(7-x)/La0.7Ca0.3MnO3 heterostructures.

    PubMed

    He, Junfeng; Shafer, Padraic; Mion, Thomas R; Vu, Thanh Tra; He, Qing; Kong, J; Chuang, Y-D; Yang, W L; Graf, M J; Lin, J-Y; Chu, Y-H; Arenholz, E; He, Rui-Hua

    2016-01-01

    Recent developments in high-temperature superconductivity highlight a generic tendency of the cuprates to develop competing electronic (charge) supermodulations. While coupled with the lattice and showing different characteristics in different materials, these supermodulations themselves are generally conceived to be quasi-two-dimensional, residing mainly in individual CuO2 planes, and poorly correlated along the c axis. Here we observed with resonant elastic X-ray scattering a distinct type of electronic supermodulation in YBa2Cu3O(7-x) (YBCO) thin films grown epitaxially on La0.7Ca0.3MnO3 (LCMO). This supermodulation has a periodicity nearly commensurate with four lattice constants in-plane, eight out of plane, with long correlation lengths in three dimensions. It sets in far above the superconducting transition temperature and competes with superconductivity below this temperature for electronic states predominantly in the CuO2 plane. Our finding sheds light on the nature of charge ordering in cuprates as well as a reported long-range proximity effect between superconductivity and ferromagnetism in YBCO/LCMO heterostructures. PMID:26927313

  7. Competition Between H2SO4(-)(CH3)3N and H2SO4-H2O Interactions: Theoretical Studies on the Clusters [(CH3)3N]·(H2SO4)·(H2O)(3-7).

    PubMed

    Xu, Zhen-Zhen; Fan, Hong-Jun

    2015-08-27

    The role of the nucleation of sulfuric acid with amines in aerosol formation and its implications for environment is one of the fundamental unsettled questions in atmospheric chemistry. We have investigated the cluster of [(CH3)3N]·(H2SO4)·(H2O)n (n = 37) by molecular dynamics to obtain configurational sampling combination with CAM-B3LYP/6-311G(d,p) level to locate the global and many local minima for each cluster size. According to the binding energies at the method of MP2/6-311++G(d,p), the total binding energies decrease with the increasing of the water molecules. For each global minimum, the average binding energies decrease from n = 3 to 4, then increase slowly. The protons of H2SO4 are preferred to transfer to the (CH3)3N to form ion-pair HSO4(–) and (CH3)3NH(+), and the (CH3)3NH(+) ions are coordinated at the first hydrated shell of HSO4(–) when n is between 3 and 5 and coordinated at the second or third hydrated shell when n is larger than 5.

  8. Electronic spectroscopy and photodissociation dynamics of Co(2+)-methanol clusters: Co2+ (CH3OH)n (n = 4-7).

    PubMed

    Thompson, Christopher J; Faherty, Kieron P; Stringer, Kay L; Metz, Ricardo B

    2005-03-01

    Solvated cluster ions Co2+ (CH3OH)n (n = 4-7) have been produced by electrospray and studied using photofragment spectroscopy. There are notable differences between the photodissociation spectra of these complexes and the analogous water complexes. Co2+ (CH3OH)6 absorbs significantly more strongly than Co2+ (H2O)6. The photodissociation spectra of Co2+ (CH3OH)n (n = 4, 5 and 6) are very similar, which suggests that they share the Co2+ (CH3OH)4 chromophore, with additional solvent molecules in the second shell. In contrast, our earlier studies indicate that Co2+ (H2O)6 is six coordinate, and its spectrum is significantly different from that of Co2+ (H2O)4. The larger clusters Co2+ (CH3OH)n (n = 5-7) dissociate by simple loss of one or more solvent molecules. Larger clusters tend to lose more solvent molecules, especially at higher photon energies. As with the corresponding water cluster, Co2+ (CH3OH)4 photodissociates by proton transfer through a salt-bridge intermediate. This is accompanied by a modest kinetic energy release of 170 kJ mol(-1) and occurs with a lifetime of 145 ns.

  9. Developmental and posthatch effects of in ovo exposure to 2,3,7,8-TCDD, 2,3,4,7,8-PECDF, and 2,3,7,8-TCDF in Japanese quail (Coturnix japonica), common pheasant (Phasianus colchicus), and white leghorn chicken (Gallus gallus domesticus) embryos.

    PubMed

    Cohen-Barnhouse, Andrew M; Zwiernik, Matthew J; Link, Jane E; Fitzgerald, Scott D; Kennedy, Sean W; Giesy, John P; Wiseman, Steve; Jones, Paul D; Newsted, John L; Kay, Denise; Bursian, Steven J

    2011-07-01

    An egg injection study was conducted to confirm a proposed model of relative sensitivity of three avian species to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-like chemicals. It was previously reported that the order of species sensitivity to in ovo exposure to TCDD, 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), or 2,3,7,8-tetrachlorodibenzofuran (TCDF) at doses ranging from 0.044 to 37 picomoles (pmol)/g egg was the chicken (Gallus gallus domesticus), common pheasant (Phasianus colchicus), and Japanese quail (Coturnix japonica) based on embryo mortality and hepatic enzyme induction. In the present study, the incidence of developmental deformities, changes in body and relative organ masses, and organ pathology of hatchlings as additional indicators of species sensitivity were assessed; in addition, embryo mortality in the three species was categorized by stage of development. Embryo mortality varied temporally with significant increases generally occurring after organogenesis and just prior to hatching. A significant increase in the percentage of developmental deformities was observed only in Japanese quail exposed to TCDF. Body and relative organ masses of quail, pheasants, and chickens dosed in ovo with TCDD, PeCDF, or TCDF were not consistently affected. Chemical-related pathology occurred only in livers of quail at the greatest doses of each compound. These results indicated that the incidence of developmental deformities, changes in body and relative organ masses and organ pathology could not be used as indicators of species sensitivity or chemical potency.

  10. Surface Broken Symmetry on Orthorhombic Double-layer Sr3(Ru1-xMnx)2 O7

    NASA Astrophysics Data System (ADS)

    Chen, Chen; Nascimento, V. B.; Diao, Zhenyu; Zhang, Jiandi; Jin, Rongying; Plummer, E. W.

    The surface of double-layered ruthenate Sr3Ru2O7 exhibits octahedra tilt distortion and an enhanced rotational distortion caused by the broken symmetry. Previous LEED IV calculation reveals that the tilt angle is (2.5+/-1.7)°at 80 K (B. Hu et. al., Physical Review B 81, 184104 (2010). A glideline symmetry and a mirror symmetry along this direction are both broken. Results from LEED IV simulations show that both broken symmetries originate from the emergence of surface tilt. The degree of broken symmetry is more sensitive to the tilt angle, thus producing a smaller error than from conventional LEED IV calculation. When Mn doping is induced into the compound, the tilt is removed and the symmetry of the LEED pattern returns to what is expected for rotation, two glide planes and four-fold symmetry. Supported by NSF DMR-1002622.

  11. Effect of Alternative Insulation Materials on Quench Propagation in ReBa2Cu3O7-delta Coils

    NASA Astrophysics Data System (ADS)

    Phillips, Makita R.

    ReBa2Cu3Odelta-7 (REBCO) coils have the potential to impact a variety of magnet applications but due to slow normal zone propagation velocity (NZPV), quench detection and protection remain difficult. It is therefore important to understand how quench behavior is affected by various aspects of coil design, geometric considerations and material properties. Although past studies have explored the effects of varying the conductor properties, it is important to investigate the influence of insulation as well. In this study, the effect of insulation properties on three-dimensional (3D) quench propagation in REBCO-based coils is investigated. At present, superconducting magnets primarily use insulators that are electrically and thermally insulating; typically Kapton. Here the impact of electrically insulating, thermally conducting insulators on quench behavior was studied. In particular, the behavior of a Kapton insulated coil was compared to doped-TiO2 and ideal Al2O3 insulated coils. A non-insulated coil was also evaluated. Using a mixed-dimensional model the effect of various insulation materials on multiple quench parameters in REBCO coated conductor coils was studied. The comparison of the usage alternative insulation was conducted for a 20 mum and 100 mum case using three models: Concept Model 1, 2 and 3. Concept model 1 studied the effects on 3D propagation behavior, including the 3D current sharing volume (CSV) and key quench parameters, including minimum quench energy, hotspot temperature and NZPV. Concept model 2 (CM 2) cooled a room temperature coil configuration from room temperature to 50 K for a 15 min duration. The radial and hoop stresses were observed at the cleavage edge, middle height and along the conductor width in the central conductor. Concept model 3 (CM 3) determined the thermal stresses based upon the thermal development of CM 1 during a quench. Concept model 1 found that ideal Al2O3 insulation resulted in the highest MQE, lowest peak temperature

  12. Synthesis, structures, electrochemical studies and antioxidant activity of 5-aryl-4-oxo-3,4,5,8-tetrahydropyrido[2,3-d]pyrimidine-7-carboxylic acids

    NASA Astrophysics Data System (ADS)

    Quiroga, Jairo; Romo, Pablo E.; Ortiz, Alejandro; Isaza, José Hipólito; Insuasty, Braulio; Abonia, Rodrigo; Nogueras, Manuel; Cobo, Justo

    2016-09-01

    The synthesis of 5-aryl-4-oxo-3,4,5,8-tetrahydropyrido[2,3-d]pyrimidine-7-carboxylic acids 3 from the reaction of 6-aminopyrimidines 1 with arylidene derivatives of pyruvic acid 2 under microwave and ultrasound irradiation is described. The orientation of cyclization process was determined by NMR measurements. The methodology provides advantages such as high yields and friendly to the environment without the use of solvents. The antioxidant properties, DPPH free radical scavenging, ORAC, and anodic potential oxidation of the new pyridopyrimidines were studied.

  13. Epitaxial growth of Ce 2Y 2O 7 buffer layers for YBa 2Cu 3O 7-δ coated conductors using reel-to-reel DC reactive sputtering

    NASA Astrophysics Data System (ADS)

    Fan, F.; Lu, Y. M.; Ying, L. L.; Liu, Z. Y.; Cai, C. B.; Hühne, R.; Holzapfel, B.

    2011-08-01

    Biaxially textured Ce 2Y 2O 7 (CYO) films were deposited on Ni-5at.%W (Ni-5W) tapes by a DC reactive sputtering technique in a reel-to-reel system. Subsequent YBa 2Cu 3O 7-δ (YBCO) films were prepared using pulsed laser deposition leading to a simplified coated conductor architecture of YBCO/CYO/Ni-5W. X-ray diffraction measurements revealed an epitaxial growth of the CYO buffer layer with a texture spread down to 2.2° and 4.7° for the out-of-plane and in-plane alignment, respectively. Microstructural investigations showed a dense, smooth and crack-free surface morphology for CYO film up to a thickness of 350 nm, implying an effective suppression of cracks due to the incorporation of Y in CeO 2. The superconducting transition temperature T c of about 90 K with a narrow transition of 0.8 K and the inductively measured critical current density J c of about 0.7 MA/cm 2 indicate the potential of the single CYO buffer layer.

  14. Novel series of potent, nonsteroidal, selective androgen receptor modulators based on 7H-[1,4]oxazino[3,2-g]quinolin-7-ones.

    PubMed

    Higuchi, Robert I; Arienti, Kristen L; López, Francisco J; Mani, Neelakhanda S; Mais, Dale E; Caferro, Thomas R; Long, Yun Oliver; Jones, Todd K; Edwards, James P; Zhi, Lin; Schrader, William T; Negro-Vilar, Andrés; Marschke, Keith B

    2007-05-17

    Recent interest in orally available androgens has fueled the search for new androgens for use in hormone replacement therapy and as anabolic agents. In pursuit of this, we have discovered a series of novel androgen receptor modulators derived from 7H-[1,4]oxazino[3,2-g]quinolin-7-ones. These compounds were synthesized and evaluated in competitive binding assays and an androgen receptor transcriptional activation assay. A number of compounds from the series demonstrated single-digit nanomolar agonist activity in vitro. In addition, lead compound (R)-16e was orally active in established rodent models that measure androgenic and anabolic properties of these agents. In this assay, (R)-16e demonstrated full efficacy in muscle and only partially stimulated the prostate at 100 mg/kg. These data suggest that these compounds may be utilized as selective androgen receptor modulators or SARMs. This series represents a novel class of compounds for use in androgen replacement therapy.

  15. Structure of trihydrated rare-earth acid diphosphates LnHP 2O 7·3H 2O ( Ln=La, Er)

    NASA Astrophysics Data System (ADS)

    Ben Moussa, S.; Ventemillas, S.; Cabeza, A.; Gutierrez-Puebla, E.; Sanz, J.

    2004-06-01

    In trihydrated lanthanum acid-diphosphates LnHP 2O 7·3H 2O, prepared from acid LnCl 3 and Na 4P 2O 7 solutions (pH=1), two crystal forms were obtained. Layered structures of two representative members of this family have been determined by single-crystal X-ray diffraction (XRD) technique. In the case of orthorhombic LaHP 2O 7·3H 2O (type I), lanthanum cations are ninefold coordinated and diphosphate groups adopt a staggered (alternated) configuration. In the case of triclinic ErHP 2O 7·3H 2O (type II), erbium cations are eightfold coordinated and diphosphate groups adopt an eclipsed configuration. In agreement with Infrared (IR) spectroscopic data, a bended configuration for diphosphate groups has been deduced. In both structures, one-dimensional chains of edge-sharing rare-earth polyhedra are linked together by diphosphate groups to form the phosphate layers. In both diphosphates, PO 4 and HPO 4 environments have been identified by 31P MAS-NMR technique. In the two compounds, OH groups of HPO 4 tetrahedra point out of diphosphate planes interacting with adjacent layers. In La-diphosphate, the interaction between HPO 4 groups and water molecules of adjacent layers is favored; however, in Er-diphosphate, the interaction between phosphate acid groups of contiguous layers is produced. Based on structural information deduced, differences detected in IR and NMR spectra of two disphosphates are discussed.

  16. Synthesis of (Ca,Ce3+,Ce4+)2Ti2O7: a pyrochlore with mixed-valence cerium

    NASA Astrophysics Data System (ADS)

    Garvie, Laurence A. J.; Xu, Huifang; Wang, Yifeng; Putnam, Robert L.

    2005-05-01

    Pyrochlore with mixed-valence Ce was synthesized by firing and annealing Ce(NO3)4, TiO2, and Ca(OH)2 with a stoichiometry of CaCeTi2O7 at 1300 °C. The product contains Ce-pyrochlore, Ce-rich perovskite, CeO2 (cerianite), and minor CaO. Electron energy-loss spectroscopy (EELS) revealed both Ce4+ and Ce3+ in the Ce-pyrochlore with a Ce4+ to total Ce (Ce4+/ΣCe) of 0.80 giving (CaCe0.213+Ce0.864+)TiO. Cerium in the perovskite and cerianite is dominated by Ce3+ and Ce4+, respectively. High-resolution transmission electron microscope (HRTEM) images show that the boundary between Ce-pyrochlore and Ce-rich perovskite is semi-coherently bonded. The orientational relationship between the neighboring Ce-pyrochlore and Ce-rich perovskite is not random. Ce-pyrochlore (CaCeTi2O7) is a chemical analogue for CaPuTi2O7, which is a proposed ceramic waste form for deposition of excess weapons-usable Pu in geological repositories. It is postulated, based on the presence of Ce3+ in the Ce-pyrochlore, that neutron poisons such as Gd can be incorporated into the CaPuTi2O7 phase.

  17. High critical current density YBa 2Cu 3O 7- δ films on surface-oxidized metallic substrates

    NASA Astrophysics Data System (ADS)

    Matsumoto, Kaname; Kim, SeokBeom; Yamagiwa, Katsuya; Koike, Yoshihiro; Hirabayashi, Izumi; Watanabe, Tomonori; Uno, Naoki; Ikeda, Masaru

    2000-06-01

    YBa 2Cu 3O 7-δ (YBCO) films with high critical current density ( Jc) were fabricated on nickel tapes buffered with bi-axially textured NiO prepared by surface-oxidation epitaxy (SOE). The effects of oxide cap layers, such as YSZ, CeO 2 and MgO, on the SOE-grown NiO were investigated to improve the superconducting properties of the YBCO films on NiO. By inserting a thin MgO cap layer between NiO layer and YBCO film, a Jc of 3×10 5 A/cm 2 (77 K, 0 T) was achieved. This result indicates the potentiality of the SOE method. In this paper, the application of the NiO/Ni substrate to non-vacuum processings, such as metal-organic deposition (MOD) and liquid phase epitaxy (LPE) will be also introduced.

  18. Electronic structure, magnetic and optical properties of the Ba7(BO3)4-xF2+3x crystal

    NASA Astrophysics Data System (ADS)

    Yelisseyev, P.; Solntsev, V. P.; Jiang, Xingxing; Bekker, T. B.; Lin, Zheshuai; Fedorov, P. P.

    2015-09-01

    Large size Ba7(BO3)4-xF2+3x (x=0.49) single crystals of optical quality, up to 20 mm in size, were grown. Crystals exhibit a wide transparent spectral range from 0.215 to 6.6 μm with the indirect energy band gaps of 4.97 and 5.09 eV at 300 and 80 K, respectively. X-ray irradiation can induce strong absorption in crystals in the UV to near IR regions, mainly from four types of paramagnetic centers: two hole-type centers where oxygen near some defect is ionized (OX1- or O1-) and two electron-type centers where fluorine vacancies capture electrons (e6- and e4-). The electron spin resonance analysis and first-principles studies identified the detailed optical transitions in these centers. The induced absorption can be removed by illumination with photon energy 2.57(BO3)4-xF2+3x both the top of valence bands and the bottom of conduction bands are composed of B 2p and O 2p orbitals. The linear and nonlinear optical properties are dominantly determined by the electron transition within (BO3)3- groups. Nonlinear susceptibility and birefringence are predicted to be d31=0.14 pm/V and 0.016 at x=0.25 and decrease to 0.01 and 0.011, respectively, as x grows to 0.75, due to the increase of F content in Ba7(BO3)4-xF2+3x.

  19. Numerical analysis of 2.7 μm lasing in Er3+-doped tellurite fiber lasers

    PubMed Central

    Wang, Weichao; Li, Lixiu; Chen, Dongdan; Zhang, Qinyuan

    2016-01-01

    The laser performance of Er3+-doped tellurite fiber lasers operating at 2.7 μm due to 4I11/2 → 4I13/2 transition has been theoretically studied by using rate equations and propagation equations. The effects of pumping configuration and fiber length on the output power, slope efficiency, threshold, and intracavity pump and laser power distributions have been systematically investigated to optimize the performance of fiber lasers. When the pump power is 20 W, the maximum slope efficiency (27.62%), maximum output power (5.219 W), and minimum threshold (278.90 mW) are predicted with different fiber lengths (0.05–5 m) under three pumping configurations. It is also found that reasonable output power is expected for fiber loss below 2 dB/ m. The numerical modeling on the two- and three-dimensional laser field distributions are further analyzed to reveal the characteristics of this multimode step-index tellurite fiber. Preliminary simulation results show that this Er3+-doped tellurite fiber is an excellent alternative to conventional fluoride fiber for developing efficient 2.7 μm fiber lasers. PMID:27545663

  20. Numerical analysis of 2.7 μm lasing in Er(3+)-doped tellurite fiber lasers.

    PubMed

    Wang, Weichao; Li, Lixiu; Chen, Dongdan; Zhang, Qinyuan

    2016-01-01

    The laser performance of Er(3+)-doped tellurite fiber lasers operating at 2.7 μm due to (4)I11/2 → (4)I13/2 transition has been theoretically studied by using rate equations and propagation equations. The effects of pumping configuration and fiber length on the output power, slope efficiency, threshold, and intracavity pump and laser power distributions have been systematically investigated to optimize the performance of fiber lasers. When the pump power is 20 W, the maximum slope efficiency (27.62%), maximum output power (5.219 W), and minimum threshold (278.90 mW) are predicted with different fiber lengths (0.05-5 m) under three pumping configurations. It is also found that reasonable output power is expected for fiber loss below 2 dB/ m. The numerical modeling on the two- and three-dimensional laser field distributions are further analyzed to reveal the characteristics of this multimode step-index tellurite fiber. Preliminary simulation results show that this Er(3+)-doped tellurite fiber is an excellent alternative to conventional fluoride fiber for developing efficient 2.7 μm fiber lasers. PMID:27545663