Science.gov

Sample records for 2 3 7

  1. 7 CFR 3.2 - Authority.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Secretary of Agriculture DEBT MANAGEMENT General § 3.2 Authority. The regulations in this part are issued... Treasury and Justice (31 CFR parts 901-904) that prescribe government-wide standards for administrative... this part also are issued under Treasury regulations implementing DCIA (31 CFR part 285) and...

  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. 7. VIEW FROM COURTYARD OF BUILDINGS 1, 2 AND 3 ...

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

    7. VIEW FROM COURTYARD OF BUILDINGS 1, 2 AND 3 LOOKING WEST ACROSS TECHWOOD DRIVE TOWARD 570-578 TECHWOOD DRIVE. - Techwood Homes (Public Housing), Bounded by North Avenue, Parker Street, William Street & Lovejoy Street, Atlanta, Fulton County, GA

  4. Synthesis and photoluminescence properties of Ln3+ (Ln3+=Tb3+, Dy3+, Sm3+, Er3+)-doped Ca2Nb2O7 phosphors

    NASA Astrophysics Data System (ADS)

    Xian, Jieqiang; Yi, Shuangping; Deng, Yaomin; Zhang, Lu; Hu, Xiaoxue; Wang, Yinhai

    2016-02-01

    A series of Ln3+ (Ln3+=Tb3+/Dy3+/Sm3+/Er3+) ions doped Ca2Nb2O7 phosphors have been synthesized by high-temperature solid-state reaction. The Ln3+-doped samples are well indexed to the pure Ca2Nb2O7 phase which revealed for the X-ray diffraction (XRD) result. Under the ultraviolet light, the prepared Ca2-xNb2O7:xLn3+ (Ln3+=Tb3+/Dy3+/Sm3+/Er3+) phosphors show the characteristic cyan (Tb3+), green-white (Sm3+), yellowish (Dy3+) and green (Er3+) emissions. The energy transfer mechanisms in Ca2Nb2O7: Tb3+/Dy3+/Sm3+/Er3+ phosphors have been investigated and it deduced to be a resonant type via an electric dipole-dipole interaction. In addition, their critical distances have been calculated by concentration quenching methods. The luminescence properties of Ca2Nb2O7:Tb3+/Dy3+/Sm3+/Er3+ phosphors indicated that the Ca2Nb2O7 is a suitable host for rare earth doped laser crystal and optical materials.

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. 2,3,7,8-TCDD, AND 2,3,7,8-TCDF AND PCB'S IN MARINE SEDIMENTS AND BIOTA: LABORATORY AND FIELD STUDIES

    EPA Science Inventory

    This report describes the bioaccumulation and depuration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF) and polychlorinated biphenyls (PCBs) by three species of marine benthos exposed to contaminated sediment collected from t...

  10. Metamagnetic Nematic Phase of Sr3Ru2O7

    NASA Astrophysics Data System (ADS)

    MacKenzie, Andrew

    2008-03-01

    In this talk I will review our group's recent observations that a quantum phase with pronounced electrical transport anisotropies forms in the vicinity of a metamagnetic quantum critical point in Sr3Ru2O7. The behaviour, which is strongly dependent on disorder and is only seen in the highest purity crystals, has phenomenological similarities with prior observations on two-dimensional electron gases in semiconductor devices [1,2]. Its appearance in bulk in Sr3Ru2O7 has allowed us to perform a number of thermodynamic measurements, and also offers the promise of study using modern surface-based spectroscopies such as angle resolved photoemission and spectroscopic imaging scanning tunneling microscopy. References [1] For example M.P. Lilly et al., Phys. Rev. Lett. 82, 394 (1999); ibid 83, 824 (1999) [2] W. Pan et al., Phys. Rev. Lett. 83, 820 (1999). Collaborators: S.A. Grigera^1, R.A. Borzi^1,2, A. Rost^1, J.F. Mercure^1, J. Farrell^1, R.S. Perry^3, A.G. Green^1, M. Allan^1, M. Wang^4, J. Lee^1, F. Baumberger^1, S.J.S Lister^1, S.L. Lee^1, J.C.S. Davis^1,4, Z.X. Shen^5, Y. Maeno^6. ^1 University of St Andrews, Scotland ^2 INFTA, La Plata, Argentina ^3 University of Edinburgh, Scotland ^4 Cornell University, USA ^5 Stanford University, USA ^6 Kyoto University, Japan

  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. 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.

  13. 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.

  14. Electron irradiation of YBa2CU3O7 ceramics

    NASA Astrophysics Data System (ADS)

    Konczykowski, Marcin; Gilchrist, John

    1991-11-01

    Irradiation treatments generally have three effects on the superconducting properties of high T_c ceramics. The superconductivity of the grains is modified, as witnessed by a shift in T_c. The mixed-state properties of the grains are changed due to the additional pinning centres, and inter-granular links are modified by the accumulation of irradiation defects at the grain boundaries. These effects are discussed with particular reference to the irradiation of polycrystalline YBa2CU3O7 at low temperature with 2-3 MeV electrons, which initially produces a random distribution of Frenkel defects. We draw attention to several kinds of measurements which can be made in situ or after transferring the sample to a measuring cryostat : the transfer allows the defects to recombine or migrate. Various DC and AC measurement methods are compared, and the three effects of irradiation are demonstrated. The irreversibility line is found to shift with T_c. Les propriétés supraconductrices des céramiques à haut T_c, sont généralement influencées dans trois domaines distincts par les irradiations. D'une part la supraconductivité des grains est modifiée, comme en témoigne le changement de T_c. D'autre part les propriétés à l'état mixte des grains sont modifiées par la présence de nouveaux centres de piégeage. Enfin les liaisons inter-granulaires sont altérées par l'accumulation de défauts d'irradiation aux joints de grains. Nous insistons particulièrement sur l'irradiation de YBa2CU3O7 polycristallin à basse température avec des électrons de 2 à 3 MeV, ce qui produit, en premier lieu, des défauts de Frenkel à répartition aléatoire. Plusieurs types de mesures peuvent être faites soit in situ, soit après transfert de l'échantillon dans un cryostat de mesures: le transfert permet la recombinaison ou la migration des défauts. Différentes méthodes en courant continu et en alternatif sont comparées, et les effets de l'irradiation sur les trois domaines ci

  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. 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

  18. Calix[4]arene Based Dual Fluorescent Sensor for Al(3+) and S2O7 (2.).

    PubMed

    Memon, Shahabuddin; Bhatti, Ashfaque Ali; Bhatti, Asif Ali; Ocak, Ümmühan; Ocak, Miraç

    2016-09-01

    Specific functionalized calix[4]arene based fluorescent chemosensor was synthesized for cations and anions binding efficiency examination. Receptor C4MA displayed strong affinity for Al(3+)and S2O7 (2-) with enhanced fluorescence intensity. The selective response of C4MA was investigated in the presence of different co-existing competing ions. The limit of detection (LOD) of Al(3+)and S2O7 (2-) was calculated as 2.8 × 10(-6) M and 2.6 × 10(-7) M respectively. Sensor C4MA forms (1:1) stoichiometric complex with both Al(3+) and S2O7 (2-) and their binding constants were calculated as 12.1 × 10(4) and 8.3 × 10(3) respectively. Complexes were also characterized through FT-IR spectroscopy. Graphical Abstract ᅟ. PMID:27324953

  19. 7 CFR 1216.2-1216.3 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions §§ 1216.2-1216.3...

  20. 7 CFR 1216.2-1216.3 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions §§ 1216.2-1216.3...

  1. 7 CFR 1216.2-1216.3 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions §§ 1216.2-1216.3...

  2. 7 CFR 1216.2-1216.3 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions §§ 1216.2-1216.3...

  3. 7 CFR 1216.2-1216.3 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions §§ 1216.2-1216.3...

  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. Chemical destruction of CH3I, C2H5I, 1-C3H7I, and 2-C3H7I in saltwater

    NASA Astrophysics Data System (ADS)

    Jones, Charlotte E.; Carpenter, Lucy J.

    2007-07-01

    Destruction of volatile iodocarbons in the oceans can potentially play an important role in determining the predominant chemical forms of iodine emitted to the atmosphere. Here we report chlorination and hydrolysis removal rates for CH3I, C2H5I, 1-C3H7I, and 2-C3H7I relevant to oceanic conditions. We have used these rates to calculate oceanic lifetimes for each iodocarbon with respect to total chemical destruction, as a function of seawater temperature. The resulting lifetimes are compared to typical iodocarbon oceanic residence times with respect to volatilization to the MBL. The rate of destruction of 2-C3H7I is much more rapid than chemical removal of the primary alkyl iodides, potentially explaining previous observations of lower 2-C3H7I concentrations in seawater compared to 1-C3H7I. Finally, in light of these results, we briefly discuss the potential impact of rising global seawater temperatures on oceanic iodocarbon concentrations.

  6. 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.

  7. 2,3,7,8-TCDD, 2,3,7,8-TCDF and PCBs in marine sediments and biota: Laboratory and field studies. Final report

    SciTech Connect

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

    1990-09-01

    The report describes the bioaccumulation and depuration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF) and polychlorinated biphenyls (PCBs) by three species of marine benthos exposed to contaminated sediment collected from the Passaic River (PR), New Jersey. Organisms were exposed to PR sediments for up to 180 days in the laboratory. In addition, sediments and associated infauna from the New York Bight were collected and analyzed for the same suite of chemical compounds.

  8. 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

  9. 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…

  10. 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.

  11. 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.

  12. Prediction of an U2S3-type polymorph of Al2O3 at 3.7 Mbar.

    PubMed

    Umemoto, Koichiro; Wentzcovitch, Renata M

    2008-05-01

    We predict by first principles a phase transition in alumina at approximately 3.7 Mbar and room temperature from the CaIrO(3)-type polymorph to another with the U(2)S(3)-type structure. Because alumina is used as window material in shock-wave experiments, this transformation should be important for the analysis of shock data in this pressure range. Comparison of our results on all high-pressure phases of alumina with shock data suggests the presence of two phase transitions in shock experiments: the corundum to Rh(2)O(3)(II)-type structure and the Rh(2)O(3)(II)-type to CaIrO(3)-type structure. The transformation to the U(2)S(3)-type polymorph is in the pressure range reached in the mantle of recently discovered terrestrial exoplanets and suggests that the multi-megabar crystal chemistry of planet-forming minerals might be related to that of the rare-earth sulfides. PMID:18451030

  13. Prediction of an U2S3-type polymorph of Al2O3 at 3.7 Mbar

    PubMed Central

    Umemoto, Koichiro; Wentzcovitch, Renata M.

    2008-01-01

    We predict by first principles a phase transition in alumina at ≈3.7 Mbar and room temperature from the CaIrO3-type polymorph to another with the U2S3-type structure. Because alumina is used as window material in shock-wave experiments, this transformation should be important for the analysis of shock data in this pressure range. Comparison of our results on all high-pressure phases of alumina with shock data suggests the presence of two phase transitions in shock experiments: the corundum to Rh2O3(II)-type structure and the Rh2O3(II)-type to CaIrO3-type structure. The transformation to the U2S3-type polymorph is in the pressure range reached in the mantle of recently discovered terrestrial exoplanets and suggests that the multi-megabar crystal chemistry of planet-forming minerals might be related to that of the rare-earth sulfides. PMID:18451030

  14. BIOAVAILABILITY OF 2,3,7,8-TCDD, 2,3,7,8-TCDF AND PCBS TO MARINE BENTHOS FROM PASSAIC RIVER SEDIMENTS

    EPA Science Inventory

    The bioaccumulation and depuration of 2,3,7,8-tetrachloro-dibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzofuran and polychlorinated biphenyls by marine benthos exposed to environmentally contaminated sediment were measured in a laboratory study. andworms (Nereis virens), clams (Macom...

  15. 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. PMID:20355659

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

    DOEpatents

    Field, George; Hammond, Peter R.

    1994-01-01

    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.

  17. 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.

  18. The interaction of MMP-2/B7-H3 in human osteoporosis.

    PubMed

    Feng, Ping; Zhang, Hong; Zhang, Zhuqiu; Dai, Xiaoli; Mao, Ting; Fan, Yinyin; Xie, Xiaofang; Wen, Huiyan; Yu, Peijuan; Hu, Yae; Yan, Ruhong

    2016-01-01

    The immune costimulatory molecule B7-H3 has been shown to be involved in the regulation of murine bone formation. However, the role of B7-H3 in bone metabolic diseases remains unknown. In our study, matrix metalloproteinase 2 (MMP-2) and soluble B7-H3 (sB7-H3) were found to be correlatively up-regulated in the sera of osteoporosis patients. Furthermore, our results showed that MG63 cells treated with MMP-2 inhibitors produced lower amounts of sB7-H3 while cells with recombinant MMP-2 had an increased membrane B7-H3 (mB7-H3) shedding. Therefore, elevated MMP-2 levels resulted in an elevation of serum sB7-H3 and reduction of osteoblastic mB7-H3. B7-H3 knockdown in MG63 cells significantly decreased osteoblastic markers and substantially decreased the number of mineralized nodules after 21days. Thus, B7-H3-deficient MG63 cells exhibited impaired bone formation. These results suggest that mB7-H3 is required for the later phases of osteoblast differentiation and that MMP-2/B7-H3 plays a negative regulatory role in osteoporosis. PMID:26631755

  19. EFFECT OF PRETREATMENT ON THE BILIARY EXCRETION OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD), 2,3,7,8-TETRACHLORODIBENZOFURAN (TCDF) NAD 3,3'4,4'-TETRACHLOROBIPHENYL (TCB) IN THE RAT

    EPA Science Inventory

    The laterally halogenated chemicals 2,3,7,8-tetrachlorodibenzofuran (TCDF) and 3,3',4,4 1-tetrachlorobiphenyl (TCB) exhibit the same spectrum of toxic effects as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) prototype and most toxic member of the halogenated aromatic hydrocarbon fam...

  20. 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,...

  1. 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,...

  2. 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,...

  3. A new cytotoxic coumarin, 7-[(E)-3',7'-dimethyl-6'-oxo-2',7'-octadienyl] oxy coumarin, from the leaves of Zanthoxylum schinifolium.

    PubMed

    Min, Bo Kyung; Hyun, Dong Geol; Jeong, Su Yang; Kim, Young Ho; Ma, Eun Sook; Woo, Mi Hee

    2011-05-01

    A new coumarin, 7-[(E)-3',7'-dimethyl-6'-oxo-2',7'-octadienyl]oxy coumarin (1), together with three known compounds, schinilenol (2), schinindiol (3) and 7-[(E)-7'-hydroxy-3',7'-dimethylocta-2',5'-dienyloxy]-coumarin (4) were isolated from the methylene chloride fraction of Z. schinifolium by normal and reverse phase column chromatographies. Their structures were determined on the basis of physical and spectroscopic evidences. Compound 1 (IC(50) 8.10 μM) showed potent cytotoxicity compared to auraptene (IC(50) 55.36 μM) against Jurkat T cells. The other isolated compounds 2 and 4 exhibited weak cytotoxicities. PMID:21656356

  4. 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

  5. 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

  6. INTERFACE DISORDER CONTROLLED SUPERCONDUCTIVITY YBa2Cu3O7 / SrTiO3 SUPERLATTICES

    SciTech Connect

    Garcia-Barriocanal, Javier; Rivera-Calzada, Alberto; Sefrioui, Z.; Arias, D; Varela del Arco, Maria; Leon, C.; Pennycook, Stephen J; Santamaria, J.

    2013-01-01

    We report on the coherent growth of 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 intra-cell 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.

  7. Human and rat primary hepatocyte CYP1A1 and 1A2 induction with 2,3,7,8-tetrachlorodibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzofuran, and 2,3,4,7,8-pentachlorodibenzofuran.

    PubMed

    Budinsky, Robert A; LeCluyse, Edward L; Ferguson, Stephen S; Rowlands, J Craig; Simon, Ted

    2010-11-01

    The concentration dose response for aryl hydrocarbon receptor (AHR)-mediated CYP1A1 and CYP1A2 messenger RNA (mRNA) induction and enzyme activity was determined in primary cultures of rat and human hepatocytes for 2,3,7,8-tetrachlorodibenzo-p-dioxin, 2,3,4,7,8-pentachlorodibenzofuran, and 2,3,7,8-tetrachlorodibenzofuran. Eleven different congener concentrations from 0.00001 to 100 nM were used, thus spanning seven orders of magnitude. The Hill model was used to obtain values of EC(x) and maximal response from the individual data sets. No-observed effect concentration values were derived using several statistical methods including Dunnett's test, the Welch-Aspin test, and step-down bilinear regression. Thresholds were estimated using baseline projection methods and a "hockey stick" fitting method. Human hepatocytes were less responsive and less sensitive with respect to CYP1A1 activity and mRNA induction than rats. On the other hand, the human CYP1A2 response was more robust than the response in rats but generally less sensitive. These data allow an evaluation of relative species sensitivities for developing interspecies toxicodynamic adjustment factors, for assessing AHR activation thresholds, and for evaluating relative congener potencies. Overall, these data support the position that humans are less sensitive than rats to these AHR-dependent end points and support the use of a data-derived adjustment factor of 1.0 or less for extrapolating between rats and humans. PMID:20705892

  8. 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.

  9. VAPOR-PHASE 2,3,7,8-TCDD SORPTION TO PLANT FOILAGE - A SPECIES COMPARISON

    EPA Science Inventory

    Plant uptake rate constants (k1) were determined for vapor-phase 2,3,7,8-TCDD using grass, azalea, spruce, kale and pepper foliage, and the fruit from apple, tomato and pepper. lants were exposed to vapor-phase 3H-2,3,7,8-TCDD for 96 h, and the TCDD sorption rate constant for eac...

  10. Induced Ferromagnetism at BiFeO3/YBa2Cu3O7 Interfaces

    PubMed Central

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

    2014-01-01

    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, 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. The emergence of interfacial ferromagnetism should have implications to electronic and transport properties. PMID:24947500

  11. 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

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Chromate(3-), bis -3- azo]-4-hydroxy-2... Substances § 721.9577 Chromate(3-), bis -3- azo]-4-hydroxy-2-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7... significant new uses subject to reporting. (1) The chemical substance identified as chromate(3-), bis -3-...

  12. 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

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Chromate(3-), bis -3- azo]-4-hydroxy-2... Substances § 721.9577 Chromate(3-), bis -3- azo]-4-hydroxy-2-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7... significant new uses subject to reporting. (1) The chemical substance identified as chromate(3-), bis -3-...

  13. 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

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Chromate(3-), bis -3- azo]-4-hydroxy-2... Substances § 721.9577 Chromate(3-), bis -3- azo]-4-hydroxy-2-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7... significant new uses subject to reporting. (1) The chemical substance identified as chromate(3-), bis -3-...

  14. 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

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Chromate(3-), bis -3- azo]-4-hydroxy-2... Substances § 721.9577 Chromate(3-), bis -3- azo]-4-hydroxy-2-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7... significant new uses subject to reporting. (1) The chemical substance identified as chromate(3-), bis -3-...

  15. 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

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Chromate(3-), bis -3- azo]-4-hydroxy-2... Substances § 721.9577 Chromate(3-), bis -3- azo]-4-hydroxy-2-naphthalene sulfonato (3-)]-,- azo]-4-hydroxy-7... significant new uses subject to reporting. (1) The chemical substance identified as chromate(3-), bis -3-...

  16. Made for "anchorin": Kv7.2/7.3 (KCNQ2/KCNQ3) channels and the modulation of neuronal excitability in vertebrate axons.

    PubMed

    Cooper, Edward C

    2011-04-01

    Kv7.2 and Kv7.3 (encoded by KCNQ2 and KCNQ3) are homologous subunits forming a widely expressed neuronal voltage-gated K(+) (Kv) channel. Hypomorphic mutations in either KCNQ2 or KCNQ3 cause a highly penetrant, though transient, human phenotype-epilepsy during the first months of life. Some KCNQ2 mutations also cause involuntary muscle rippling, or myokymia, which is indicative of motoneuron axon hyperexcitability. Kv7.2 and Kv7.3 are concentrated at axonal initial segments (AISs), and at nodes of Ranvier in the central and peripheral nervous system. Kv7.2 and Kv7.3 share a novel ∼80 residue C-terminal domain bearing an "anchor" motif, which interacts with ankyrin-G and is required for channel AIS (and likely, nodal) localization. This domain includes the sequence IAEGES/TDTD, which is analogous (not homologous) to the ankyrin-G interaction motif of voltage-gated Na(+) (Na(V)) channels. The KCNQ subfamily is evolutionarily ancient, with two genes (KCNQ1 and KCNQ5) persisting as orthologues in extant bilaterian animals from worm to man. However, KCNQ2 and KCNQ3 arose much more recently, in the interval between the divergence of extant jawless and jawed vertebrates. This is precisely the interval during which myelin and saltatory conduction evolved. The natural selection for KCNQ2 and KCNQ3 appears to hinge on these subunits' unique ability to be coordinately localized with Na(V) channels by ankyrin-G, and the resulting enhancement in the reliability of neuronal excitability. PMID:20940059

  17. Photolysis of octachlorodibenzo-p-dioxin on soils: Production of 2,3,7,8-tcdd

    SciTech Connect

    Miller, G.C.; Hebert, V.R.; Miille, M.J.; Mitzel, R.; Zepp, R.G.

    1989-01-01

    Photolysis of octachlorodibenzo-p-dioxin (OCDD) on soils results in production of the lower chlorinated dibenzo-p-dioxins, notably 2,3,7,7-tetrachloro-dibenzo-p-dioxin (2,3,7,8-TCDD), 1,2,3,7,8-pentachlorodibenzo-p-dioxin (1,2,3,7,8-PCDD) and three hexachlorodibenzo-p-dioxin isomers substituted at the 2,3,7,8-positions. Photodechlorination is favored at the lateral positions for the H6CDD and P5CDD congeners, based on the relative yields of the various isomers produced. The mean depth of photolysis of OCDD in the two soils examined varied between 0.06 and 0.13 mm.

  18. 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

    ...-amino-3- phebyl]azo]-3,3â²-dimethyl -4-yl]azo]-5-hydroxy-6-(phenylazo)-, disodium salt. 721.5279 Section... 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-...

  19. 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

    ...-amino-3- phebyl]azo]-3,3â²-dimethyl -4-yl]azo]-5-hydroxy-6-(phenylazo)-, disodium salt. 721.5279 Section... 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-...

  20. Magnetic anisotropic behavior in epitaxial La2/3Ca1/3MnO3/YBa2Cu3O7-δ/La2/3Ca1/3MnO3 and La2/3Ca1/3MnO3/La1/3Ca2/3MnO3/YBa2Cu3O7-δ trilayered structures

    NASA Astrophysics Data System (ADS)

    Morán, O.; Perez, F.; Saldarriaga, W.; Gross, K.; Baca, E.

    2008-04-01

    The temperature dependence of the magnetization along with magnetization hysteresis loops were measured on dc sputtered La2/3Ca1/3MnO3[ferromagneticwidth="0.3em"/>(F)]/YBa2Cu3O7-δ[superconductor(S)]/La2/3Ca1/3MnO3(F) and La2/3Ca1/3MnO3(F)/La1/3Ca2/3MnO3[antiferromagnetic(AF)]/YBa2Cu3O7δ(S) trilayered structures. The magnetic fields were applied both parallel (in-plane) and perpendicular (out-of-plane) to the film plane. Magnetization hysteresis loops, recorded at 5K, shown a clear central peak around zero field when the magnetic field was applied perpendicular to the film plane and a typical ferromagnetic behavior when applied parallel. Additionally, the dependence of the magnetization on the temperature, performed under the zero-field-cooling (ZFC) and field-cooling (FC) regimens, evidenced the active presence of the diamagnetic and ferromagnetic phases both in the F/S/F and F/AF/S trilayers. Thus, the diamagnetic phase was clearly observed under the ZFC regimen, whereas a possible paramagnetic Meissner effect was observed under the FC regimen.

  1. 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.

  2. 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.

  3. Beta-globin mRNAs capped with m7G, m2.7(2)G or m2.2.7(3)G differ in intrinsic translation efficiency.

    PubMed Central

    Darzynkiewicz, E; Stepinski, J; Ekiel, I; Jin, Y; Haber, D; Sijuwade, T; Tahara, S M

    1988-01-01

    We examined the intramolecular effect of altered cap structures on translation efficiency of artificial beta-globin mRNAs. For these studies, synthetic dinucleotides of the form X(5')ppp(5')G [X = 7-methyl guanosine (m7G), 2,7-dimethyl guanosine (m2(2,7)G) or 2,2,7-trimethyl guanosine (m3(2,2,7)G)], were transcriptionally incorporated into mRNAs, containing rabbit beta-globin coding sequences, using T7 RNA polymerase and a beta-globin cDNA template. These synthetic mRNAs were assayed in reticulocyte lysate for activity relative to m7G-capped mRNA. m2(2,7)G-Capped mRNA was found to be 1.5-fold more active than m7G-capped mRNA. Messenger RNA capped with m3(2,2,7)G was less active with activity of 0.24 relative to its m7G-capped counterpart (activity = 1.0). These data suggest that m7G-capped mRNAs become more active as translation templates after addition of a single N2 methyl moiety, which is especially pertinent to gene expression in togaviridae. The latter are observed to synthesize m2(2,7)G and m3(2,2,7)G-capped mRNAs in addition to m7G-capped templates during the course of infection in animal cells. Images PMID:3174438

  4. Paramagnetic Meissner effect in Y Ba2 Cu3 O7 / La0.7 Ca0.3 Mn O3 superlattices

    NASA Astrophysics Data System (ADS)

    López de La Torre, M. A.; Peña, V.; Sefrioui, Z.; Arias, D.; Leon, C.; Santamaria, J.; Martinez, J. L.

    2006-02-01

    We report the observation of a paramagnetic contribution to the field cooled magnetization that develops below the superconducting transition temperature Tc in measurements performed on YBa2Cu3O7/La0.7Ca0.3MnO3 superlattices. The effect has been detected only for samples whose manganite layers are magnetically granular. We discuss our observation of this paramagnetic Meissner effect (Wohlleben effect) in terms of an inhomogeneous superconducting state at the interface with the magnetically granular manganite layers.

  5. 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.

  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, 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...

  7. Synthesis and properties of new derivatives of ethyl 7-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrido [2,3-d]pyrimidine-5-carboxylate.

    PubMed

    Sladowska, H; Bartoszko-Malik, A; Zawisza, T

    1990-01-01

    Condensation of diethyl 2-amino-6-methylpyridine-3,4-dicarboxylate with phenyl or cyclohexyl isocyanates gave the corresponding derivatives of ethyl 7-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrido [2,3-d]pyrimidine- 5-carboxylate[(V), (VI)]. Alkylation of (V) and (VI) afforded the corresponding N-1 substituted derivatives (XI-XIX). PMID:2337441

  8. Heteromeric Kv7.2/7.3 channels differentially regulate action potential initiation and conduction in neocortical myelinated axons.

    PubMed

    Battefeld, Arne; Tran, Baouyen T; Gavrilis, Jason; Cooper, Edward C; Kole, Maarten H P

    2014-03-01

    Rapid energy-efficient signaling along vertebrate axons is achieved through intricate subcellular arrangements of voltage-gated ion channels and myelination. One recently appreciated example is the tight colocalization of K(v)7 potassium channels and voltage-gated sodium (Na(v)) channels in the axonal initial segment and nodes of Ranvier. The local biophysical properties of these K(v)7 channels and the functional impact of colocalization with Na(v) channels remain poorly understood. Here, we quantitatively examined K(v)7 channels in myelinated axons of rat neocortical pyramidal neurons using high-resolution confocal imaging and patch-clamp recording. K(v)7.2 and 7.3 immunoreactivity steeply increased within the distal two-thirds of the axon initial segment and was mirrored by the conductance density estimates, which increased from ~12 (proximal) to 150 pS μm(-2) (distal). The axonal initial segment and nodal M-currents were similar in voltage dependence and kinetics, carried by K(v)7.2/7.3 heterotetramers, 4% activated at the resting membrane potential and rapidly activated with single-exponential time constants (~15 ms at 28 mV). Experiments and computational modeling showed that while somatodendritic K(v)7 channels are strongly activated by the backpropagating action potential to attenuate the afterdepolarization and repetitive firing, axonal K(v)7 channels are minimally recruited by the forward-propagating action potential. Instead, in nodal domains K(v)7.2/7.3 channels were found to increase Na(v) channel availability and action potential amplitude by stabilizing the resting membrane potential. Thus, K(v)7 clustering near axonal Na(v) channels serves specific and context-dependent roles, both restraining initiation and enhancing conduction of the action potential. PMID:24599470

  9. Heteromeric Kv7.2/7.3 Channels Differentially Regulate Action Potential Initiation and Conduction in Neocortical Myelinated Axons

    PubMed Central

    Battefeld, Arne; Tran, Baouyen T.; Gavrilis, Jason; Cooper, Edward C.

    2014-01-01

    Rapid energy-efficient signaling along vertebrate axons is achieved through intricate subcellular arrangements of voltage-gated ion channels and myelination. One recently appreciated example is the tight colocalization of Kv7 potassium channels and voltage-gated sodium (Nav) channels in the axonal initial segment and nodes of Ranvier. The local biophysical properties of these Kv7 channels and the functional impact of colocalization with Nav channels remain poorly understood. Here, we quantitatively examined Kv7 channels in myelinated axons of rat neocortical pyramidal neurons using high-resolution confocal imaging and patch-clamp recording. Kv7.2 and 7.3 immunoreactivity steeply increased within the distal two-thirds of the axon initial segment and was mirrored by the conductance density estimates, which increased from ∼12 (proximal) to 150 pS μm−2 (distal). The axonal initial segment and nodal M-currents were similar in voltage dependence and kinetics, carried by Kv7.2/7.3 heterotetramers, 4% activated at the resting membrane potential and rapidly activated with single-exponential time constants (∼15 ms at 28 mV). Experiments and computational modeling showed that while somatodendritic Kv7 channels are strongly activated by the backpropagating action potential to attenuate the afterdepolarization and repetitive firing, axonal Kv7 channels are minimally recruited by the forward-propagating action potential. Instead, in nodal domains Kv7.2/7.3 channels were found to increase Nav channel availability and action potential amplitude by stabilizing the resting membrane potential. Thus, Kv7 clustering near axonal Nav channels serves specific and context-dependent roles, both restraining initiation and enhancing conduction of the action potential. PMID:24599470

  10. 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.

  11. Induced Ferromagnetism at BiFeO3/YBa2Cu3O7 Interfaces

    DOE PAGESBeta

    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

  12. 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. PMID:23381266

  13. Human health effects after exposure to 2,3,7,8-TCDD.

    PubMed

    Sweeney, M H; Mocarelli, P

    2000-04-01

    In 1949, the first descriptions of human exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD)-contaminated chemicals were reported after a trichlorophenol reactor explosion in Nitro, West Virginia, USA. Reported non-cancer health effects included a range of conditions affecting most systems. Additional reports of the health consequences of exposure continued through the remainder of the century. The majority of effects have been reported among highly exposed groups including occupational populations, such as chemical production workers, pesticide applicators, and individuals who handled or were exposed to materials treated with 2,3,7,8-TCDD-contaminated pesticides, and among residents of communities contaminated with tainted waste oil (Missouri, USA) and industrial effluent (Seveso, Italy). For only six exposed populations were biological measurements of 2,3,7,8-TCDD-contaminated collected and used to examine the relationship between non-cancer health effects and exposure. Of the many non-cancer health effects thought to be associated with 2,3,7,8-TCDD exposure, only chloracne, elevations in GGT and triglyceride levels, and alterations in FSH and LH were related to serum 2,3,7,8-TCDD levels. Mortality from cardiovascular diseases also appeared to be elevated among cohorts of exposed chemical workers and Seveso residents. Continued surveillance of the health of exposed populations will be useful in identifying the long-term effects of both high and low 2,3,7,8-TCDD exposure. PMID:10912244

  14. Estimating exposures to 2,3,7,8-TCDD. Draft report

    SciTech Connect

    Not Available

    1988-03-01

    This exposure assessment document provides a review and update of information related to exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). Several scenarios are constructed to illustrate how contaminated material from contaminated soil, various land-disposal situations, and municipal-waste incineration can result in exposure to 2,3,7,8-TCDD. Estimates are also provided to show what the human exposure and risk would be via inhalation, dermal contact, and ingestion of contaminated soil. Part One presents an update of previous work and an analysis of key issues related to exposure assessment for chlorinated dibenzo-p-dioxins with emphasis on 2,3,7,8-TCDD, such as the behavior of 2,3,7,8-TCDD in soil and sediment, bioavailability from soil, the use of pharmacokinetics for estimating 2,3,7,8-TCDD exposures, and plant uptake. Part Two addresses the application of exposure-assessment methods discussed in Part One, in evaluating 2,3,7,8-TCDD exposures from selected situations. Twenty different exposure scenarios, covering contaminated soil, landfills, and incineration are presented. Human exposure and risk calculations are then computed under each pathway for the different scenarios.

  15. [Analgesic activity of derivatives of 7-amino-2,3-polymethylenindoles and their congeners].

    PubMed

    Cerri, R; Boatto, G; Pau, A; Sparatore, F; Manca, P

    1988-02-01

    Some N-trifluoromethylsulphonyl and N-trifluoroacetylderivatives of 7-amino-2,3-polymethyleneindoles and of 7-amino-3-propylindole [(I) - (XIII)] were prepared and tested, together with corresponding aniline derivates [(XIV) - (XIX)] and with N-trifluoromethylsulphonylcyclopentylamine (XX), against formic acid induced writhings in mice. With very few exceptions, at the oral dose of 0.167 mmole/kg, they proved from 2 to 3.4 times more active than acetanilide. PMID:3391261

  16. 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.

  17. E3 Ubiquitin Ligase Fbw7 Negatively Regulates Osteoblast Differentiation by Targeting Runx2 for Degradation.

    PubMed

    Kumar, Yogesh; Kapoor, Isha; Khan, Kainat; Thacker, Gatha; Khan, Mohd Parvez; Shukla, Nidhi; Kanaujiya, Jitendra Kumar; Sanyal, Sabyasachi; Chattopadhyay, Naibedya; Trivedi, Arun Kumar

    2015-12-25

    Runx2, a master regulator of osteoblast differentiation, is tightly regulated at both transcriptional and post-translational levels. Post-translational modifications such as phosphorylation and ubiquitination have differential effects on Runx2 functions. Here, we show that the reduced expression and functions of Runx2 upon its phosphorylation by GSK3β are mediated by its ubiquitin-mediated degradation through E3 ubiquitin ligase Fbw7α. Fbw7α through its WD domain interacts with Runx2 both in a heterologous (HEK293T cells) system as well as in osteoblasts. GSK3β was also present in the same complex as determined by co-immunoprecipitation. Furthermore, overexpression of either Fbw7α or GSK3β was sufficient to down-regulate endogenous Runx2 expression and function; however, both failed to inhibit endogenous Runx2 when either of them was depleted in osteoblasts. Fbw7α-mediated inhibition of Runx2 expression also led to reduced Runx2 transactivation and osteoblast differentiation. In contrast, inhibition of Fbw7α restored Runx2 levels and promoted osteoblast differentiation. We also observed reciprocal expression levels of Runx2 and Fbw7α in models of bone loss such as lactating (physiological bone loss condition) and ovariectomized (induction of surgical menopause) animals that show reduced Runx2 and enhanced Fbw7α, whereas this was reversed in the estrogen-treated ovariectomized animals. In addition, methylprednisolone (a synthetic glucocorticoid) treatment to neonatal rats showed a temporal decrease in Runx2 with a reciprocal increase in Fbw7 in their calvarium. Taken together, these data demonstrate that Fbw7α negatively regulates osteogenesis by targeting Runx2 for ubiquitin-mediated degradation in a GSK3β-dependent manner and thus provides a plausible explanation for GSK3β-mediated bone loss as described before. PMID:26542806

  18. 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.

  19. 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.

  20. 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.

  1. Block by Block Growth of Ultrathin YBa2Cu3O 7-x in YBa2Cu3O 7-x/PrBa2Cu3O7 Superlattices

    NASA Astrophysics Data System (ADS)

    Varela, Maria; Grogger, Werner; Arias, Diego; Sefrioui, Zouhair; Leon, Carlos; Ballesteros, Carmen; Krishnan, Kannan M.; Santamaria, Jacobo

    2001-03-01

    High quality [YBa2Cu3O 7-x n u.c. /PrBa2Cu3O7 5 u.c.] 1000Å superlattices with noninteger YBa2Cu3O7-x layer thickness have been grown to investigate the growth mechanism of YBCO. We unambiguously show the block by block deposition as opposed to atomic layer by layer growth modes [1,2]. Samples were grown on SrTiO3 substrates by high oxygen pressure sputtering. Interfacial morphology has been characterized by x-ray diffraction (XRD) and energy filtered transmission electron microscopy (EFTEM). X ray refinement shows no interdiffusion, negligible interfacial roughness and significant epitaxial strain for YBCO layers, with thickness below 3 unit cells [3, 4]. X ray analysis shows that in superlattices with non integer YBCO layers, the superlattice modulation length does not commensurate with the underlying lattice [5]. EFTEM analysis shows the presence of interface steps one unit cell high, distributed in such a way that the interface plane composition changes coherently with increasing bilayer index. While a layer by layer growth would yield continuous one unit cell thick layers (and eventually Y/Pr alloys) the block by block growth mode results in one unit cell thick islands not completely covering the substrate surface. [1] T. Terashima, Y. Bando, K. Iijima, K. Yamamoto, K. Hiata, K. Hayashi, K. Kamigaki, H. Terauchi. Phys. Rev. Lett. 65 2684 (1990). [2] J.P. Locquet, A. Catana, E. Mächler, C. Gerber, J.G. Bednorz, Appl. Phys. Lett. 64, 372 (1994). [3] M.Varela, Z. Sefrioui, D. Arias, M. A. Navacerrada, M. Lucia, M. A. Lopez de la Torre, G. D. Loos, C. Leon, F. Sanchez-Quesada, J. Santamaría, Phys. Rev. Lett. 83, 3936 (1999). [4] M. Varela, D. Arias, Z. Sefrioui, C. León, C. Ballesteros, J. Santamaría. Phys. Rev. B 62 12509 (2000) [5] I. K. Schuller, M. Grimsditch, F. Chambers, G. Devane, H. Vanderstraeten, D. Neerinck, J.-P. Locquet, Y. Bruynseraede. Phys. Rev. Lett. 65 1235 (1990). + Financial support from CICYT grant nr.MAT99 1706E is acknowledged. Work at

  2. 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

  3. XANES and EXAFS study of Au-substituted YBa2Cu3O(7-delta)

    NASA Technical Reports Server (NTRS)

    Ruckman, Mark W.; Hepp, Aloysius F.

    1990-01-01

    The near-edge structure (XANES) of the Au L3 and Cu K edges of YBa2Au(0.3)Cu(2.7)O(7-delta) was studied. X ray diffraction suggests that Au goes on the Cu(1) site and XANES shows that this has little effect on the oxidation state of the remaining copper. The gold L3 edge develops a white line feature whose position lies between that of trivalent gold oxide (Au2O3) and monovalent potassium gold cyanide (KAu(CN)2) and whose intensity relative to the edge step is smaller than in the two reference compounds. The L3 EXAFS for Au in the superconductor resembles that of Au2O3. However, differences in the envelope of the Fourier filtered component for the first shell suggest that the local structure of the Au in the superconductor is not equivalent to Au2O3.

  4. Mechanism of Dis3l2 substrate recognition in the Lin28-let-7 pathway.

    PubMed

    Faehnle, Christopher R; Walleshauser, Jack; Joshua-Tor, Leemor

    2014-10-01

    The pluripotency factor Lin28 inhibits the biogenesis of the let-7 family of mammalian microRNAs. Lin28 is highly expressed in embryonic stem cells and has a fundamental role in regulation of development, glucose metabolism and tissue regeneration. Overexpression of Lin28 is correlated with the onset of numerous cancers, whereas let-7, a tumour suppressor, silences several human oncogenes. Lin28 binds to precursor let-7 (pre-let-7) hairpins, triggering the 3' oligo-uridylation activity of TUT4 and TUT7 (refs 10-12). The oligoU tail added to pre-let-7 serves as a decay signal, as it is rapidly degraded by Dis3l2 (refs 13, 14), a homologue of the catalytic subunit of the RNA exosome. The molecular basis of Lin28-mediated recruitment of TUT4 and TUT7 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 that of its exosome counterpart. The resulting path reveals an extensive network of uracil-specific interactions spanning the first 12 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

  5. Calculation of 2,3,7,8-TCDD equivalent concentrations of complex environmental contaminant mixtures

    PubMed Central

    Eadon, George; Kaminsky, Laurence; Silkworth, Jay; Aldous, Kenneth; Hilker, David; O'Keefe, Patrick; Smith, Robert; Gierthy, John; Hawley, John; Kim, Nancy; DeCaprio, Anthony

    1986-01-01

    Sufficient toxicological data are now available to permit use of conventional risk assessment techniques to estimate the hazards associated with human exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). However, many real-world exposures involve complex mixtures of dibenzodioxins, dibenzofurans, and related compounds. Historical approaches to risk assessment on such mixtures have ranged from ignoring all compounds except 2,3,7,8-TCDD itself to assuming that all compounds have potencies equal to 2,3,7,8-TCDD. An alternative approach which uses existing literature data and analytical results to calculate the “2,3,7,8-TCDD equivalent” concentration of a mixture in order to “predict” its biological potency relative to 2,3,7,8-TCDD itself is advanced here. Previously reported in vivo acute and subchronic studies and some recently obtained analytical chemistry data are integrated here to clarify the utility of this important approach and to assess the uncertainties associated with its use. This predictive approach, and various conceptually similar ones, have now found wide applicability to the risk assessment process associated with exposure to complex mixtures of dioxins, dibenzofurans, and related compounds. PMID:3830107

  6. 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

  7. Calculation of 2,3,7,8-TCDD equivalent concentrations of complex environmental contaminant mixtures

    SciTech Connect

    Eadon, G.; Kaminsky, L.; Silkworth, J.; Aldous, K.; Hilker, D.; O'Keefe, P.; Smith, R.; Gierthy, J.; Hawley, J.; Kim, N.

    1986-12-01

    Sufficient toxicological data are now available to permit use of conventional risk assessment techniques to estimate the hazards associated with human exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). However, many real-world exposures involve complex mixtures of dibenzodioxins, dibenzofurans, and related compounds. Historical approaches to risk assessment on such mixtures have ranged from ignoring all compounds except 2,3,7,8-TCDD itself to assuming that all compounds have potencies equal to 2,3,7,8-TCDD. An alternative approach which uses existing literature data and analytical results to calculate the 2,3,7,8-TCDD equivalent concentration of a mixture in order to predict its biological potency relative to 2,3,7,8-TCDD itself is advanced here. Previously reported in vivo acute and subchronic studies and some recently obtained analytical chemistry data are integrated here to clarify the utility of this important approach and to assess the uncertainties associated with its use. This predictive approach, and various conceptually similar ones, have now found wide applicability to the risk assessment process associated with exposure to complex mixtures of dioxins, dibenzofurans, and related compounds.

  8. 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

  9. Coherent acoustic phonons in YBa2Cu3O7/La1/3Ca2/3MnO3 superlattices

    NASA Astrophysics Data System (ADS)

    Li, Wei; He, Bin; Zhang, Chunfeng; Liu, Shenghua; Liu, Xiaoran; Middey, S.; Chakhalian, J.; Wang, Xiaoyong; Xiao, Min

    2016-03-01

    We investigate photo-induced coherent acoustic phonons in complex oxide superlattices consisting of high-Tc superconductor YBa2Cu3O7-x and ferromagnetic manganite La1/3Ca2/3MnO3 epitaxial layers with broadband pump-probe spectroscopy. Two oscillatory components have been observed in time-resolved differential reflectivity spectra. Based on the analysis, the slow oscillation mode with a frequency sensitive to the probe wavelength is ascribed to the stimulated Brillouin scattering due to the photon reflection by propagating train of coherent phonons. The fast oscillation mode with a probe-wavelength-insensitive frequency is attributed to the Bragg oscillations caused by specular phonon reflections at oxide interfaces or the electron-coupling induced modulation due to free carrier absorption in the metallic superlattices. Our findings suggest that oxide superlattice is an ideal system to tailor the coherent behaviors of acoustic phonons and to manipulate the thermal and acoustic properties.

  10. Measurement of magnetic exchange in ferromagnet-superconductor La2/3Ca1/3MnO3/YBa2Cu3O7 bilayers.

    PubMed

    Giblin, S R; Taylor, J W; Duffy, J A; Butchers, M W; Utfeld, C; Dugdale, S B; Nakamura, T; Visani, C; Santamaria, J

    2012-09-28

    The existence of coherent magnetic correlations in the normal phase of cuprate high-temperature superconductors has proven difficult to measure directly. Here we report on a study of ferromagnetic-superconductor bilayers of La2/3Ca1/3MnO3/YBa2Cu3O7 (LCMO/YBCO) with varying YBCO layer thicknesses. Using x-ray magnetic circular dichroism, we demonstrate that the ferromagnetic layer induces a Cu magnetic moment in the adjacent high-temperature superconductor. For thin samples, this moment exists at all temperatures below the Curie temperature of the LCMO layer. However, for a YBCO layer thicker than 12 unit cells, the Cu moment is suppressed for temperatures above the superconducting transition, suggesting this to be a direct measurement of magnetic coherence in the normal state of a superconducting oxide. PMID:23030115

  11. 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.

  12. Regulation of TRPM7 Function by IL-6 through the JAK2-STAT3 Signaling Pathway

    PubMed Central

    Wang, Jing; Zhao, Yin; Luo, Zhenzhao; Gao, Yan; Shi, Jing

    2016-01-01

    Aims Previous studies have demonstrated that expression of the TRPM7 channel, which may induce delayed cell death by mediating calcium influx, is precisely regulated. However, functional regulation of TRPM7 channels by endogenous molecules has not been elucidated. The proinflammatory cytokine IL-6 contributes to regulation of Ca2+ influx in cerebral ischemia, but the role of IL-6 in regulating TRPM7 functioning is unknown. Thus, we here investigated the interaction between IL-6 and TRPM7 channels and the relevant mechanisms. Materials and Methods Using whole-cell patch-clamping, we first investigated the effect of IL-6 on TRPM7-like currents in primary cultured cortical neurons. Next, TRPM7-overexpressing HEK293 cells were used to confirm the effect of IL-6/sIL-6R on TRPM7. Finally, we used specific signaling pathway inhibitors to investigate the signaling pathways involved. Results IL-6 or IL-6/sIL-6R dose-dependently inhibited inward TRPM7 currents, in both primary cultured neurons and HEK293 cells overexpressing TRPM7. In intracellular Mg2+-free conditions, extracellular Ca2+ or the α-kinase domain of TRPM7 did not participate in this regulation. The inhibitory effect of IL-6 on TRPM7 could be blocked by specific inhibitors of the JAK2−STAT3 pathway, but not of the PI3K, ERK1/2, or PLC pathways. Conclusions IL-6 inhibits the inward TRPM7 current via the JAK2−STAT3 signaling pathway. PMID:27010689

  13. Hollow CoFe2O4-Co3Fe7 microspheres applied in electromagnetic absorption

    NASA Astrophysics Data System (ADS)

    Li, Wanxi; Wang, Liancheng; Li, Guomin; Xu, Yao

    2015-03-01

    In this work, monodisperse hollow cobalt ferrite (CoFe2O4) microspheres with mean diameter of 150 nm and shell thickness of 50 nm have been successfully prepared via a one-pot solvothermal method. In order to improve the microwave absorption, a thermal reduction process was designed to synthesize hollow CoFe2O4-Co3Fe7 microspheres. Scanning electron microscopy and transmission electron microscopy images showed that the CoFe2O4-Co3Fe7 microspheres retained hollow structure. Microwave absorption results revealed that hollow CoFe2O4-Co3Fe7 microspheres exhibited much stronger electromagnetic absorption than the original hollow CoFe2O4 microspheres. Most importantly, when the sample thickness was 1.3 mm, the reflection loss (RL) less than -10 dB was obtained in the frequency range of 12.5-17.7 GHz, which nearly covered the entire Ku-band. When the sample thickness increased to 2 mm, the minimum RL was as high as -41.6 dB with the effective bandwidth (the bandwidth of RL at -10 dB) of 3 GHz. The enhanced microwave absorption was attributed to efficient complement between dielectric loss and magnetic loss. These results indicated that the hollow CoFe2O4-Co3Fe7 microspheres could be used as a new candidate for microwave absorbents, especially in Ku-band.

  14. YBa2Cu3O(7-delta)/Au/Nb sandwich geometry SNS weak links on c-axis oriented YBa2Cu3O(7-delta)

    NASA Technical Reports Server (NTRS)

    Foote, M. C.; Hunt, B. D.; Bajuk, L. J.

    1991-01-01

    Sandwich geometry superconductor/normal metal/superconductor structures have been fabricated on LaAlO3 and cubic zirconia with laser-ablated, c-axis-oriented YBa2Cu3O(7-delta) base electrodes, 100-600 A of Au, and Nb counter electrodes, all formed in situ without breaking vacuum. Junctions range in size from 5 to 50 micron on a side. Four probe I-V measurements at 4.2 K show RnA products as low as 6 x 10 to the -9th sq cm and critical current densities up to 5.2 kA/sq cm. AC Josephson steps were observed with the application of 10-GHz radiation. The temperature dependence of Jc and the observation of the AC Josephson effect suggest that true supercurrents are present and that they do indeed represent the characteristics of the YBa2Cu3O(7-delta)/Au/Nb structure. The best results were obtained when the devices were annealed at about 450 C in O2 for 30 min after Au deposition.

  15. 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

  16. 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

  17. Optimization of YBa sub 2 Cu sub 3 O sub 7 thin films for multilayers

    SciTech Connect

    Humphreys, R.G.; Chew, N.G.; Satchell, J.S.; Goodyear, S.W.; Edwards, J.A.; Blenkinsop, S.E. )

    1991-03-01

    This paper studies the in situ growth of YBa{sub 2}Cu{sub 3}O{sub 7} thin films using e-beam coevaporation. The growth conditions for smooth YBa{sub 2}Cu{sub 3}O{sub 7} films with high T{sub c} and J{sub c} have been established. Superconductor-insulator and SIS structures have been grown using Y{sub 2}O{sub 3} as an epitaxial insulator, and preliminary vertical transport measurements in patterned structures are reported.

  18. Mixed Valent Gold Oxides: Syntheses, Structures, and Properties of Rb 5Au 3O 2, Rb 7Au 5O 2, and Cs 7Au 5O 2

    NASA Astrophysics Data System (ADS)

    Mudring, Anja-Verena; Nuss, Jürgen; Wedig, Ulrich; Jansen, Martin

    2000-11-01

    The title compounds Rb5Au3O2, Rb7Au5O2, and Cs7Au5O2 are the first examples of mixed valent phases containing gold in the oxidation states +1 and -1. Their crystal structures (Rb5Au3O2, Pbam, a=736.4(1) pm, b=1430.8(2) pm, c=567.9(1) pm, Z=2, R(F)=0.053, 647 reflections; Rb7Au5O2, Immm, a=567.1(2) pm, b=930.1(1) pm, C=1659.4(3) pm, Z=2, R(F)=0.066, 409 reflections; Cs7Au5O2, Immm, a=599.4(1) pm, b=960.6(3) pm, c=1720.8(12) pm, Z=2, R(F)=0.039, 386 reflections) are characterized by the combination of distinctive structural features of gold(I) oxides and aurides: for Au(+1) a typical linear coordination by oxygen is found and the surroundings of Au(-1) bear a close resemblance to the binary 1:1 aurides. In consequence the overall structures of Rb5Au3O2 and M7Au5O2 can be described as intergrowths of M3AuO2 and MAu (M=Rb, Cs), constituting members of a homologous series [MAu]n[M3AuO2] with n=2 and 4, respectively. The crystal chemical evidence for the valence states assumed, also confirmed by Mößbauer spectroscopy, is supported by various band structure calculations (Hartee-Fock and density functional) clearly indicating the coexistence of two different oxidation states. The compounds have been synthesized by reacting binary aurides MAu and alkali monoxides M2O (M=Rb, Cs) with elemental gold in the required stochiometric amounts. Hereby, a further astonishing parallel to the chemistry of halogens is revealed. Like these, gold disproportionates upon interaction with bases.

  19. Synthesis, photoluminescence and thermoluminescence properties of LiNa3P2O7:Tb3+ green emitting phosphor

    NASA Astrophysics Data System (ADS)

    Munirathnam, K.; Dillip, G. R.; Ramesh, B.; Joo, S. W.; Prasad Raju, B. Deva

    2015-11-01

    The alkaline phosphate based LiNa3P2O7:Tb3+ phosphors are prepared by solid state reaction method. X-ray diffraction (XRD) analysis shows that all the powders possess orthorhombic structure. Fourier transform infrared (FTIR) spectroscopy studies suggest that the phosphor belong to the diphosphate family. The morphology of the phosphors is identified by scanning electron microscopy (SEM). Upon 378 nm excitation, the LiNa3P2O7:Tb3+ phosphors shown emission bands at 482, 545, 588 and 620 nm corresponding to the transitions 5D4→7F6, 5D4→7F5, 5D4→7F4 and 5D4→7F3, respectively. The optimized concentration of Tb3+ in LiNa3P2O7 phosphor is found to be 9 mol%. The concentration quenching mechanism was proved to be the exchange interaction between two nearest Tb3+ ions with the critical distance (Rc) of 1.18 nm. The Commission International de l'Eclairage (CIE) coordinates evidence that the phosphors emit in the green light region. Thermoluminescence properties of the prepared phosphors are studied by pre-irradiating the powders with different doses of UV irradiation. The kinetic parameters of TL glow curves are calculated using Chen's peak shape method.

  20. 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

  1. 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

  2. Structural Study of Electrochemically Obtained Li 2+ xTi 3O 7

    NASA Astrophysics Data System (ADS)

    Arroyo y de Dompablo, M. E.; Várez, A.; García-Alvarado, F.

    2000-08-01

    Li2Ti3O7, a ramsdellite-type compound, is able to reversibly insert approximately 2.3 lithium ions per formula down to 1 V versus lithium. Both electron and X-ray diffraction techniques show that the electrochemically inserted compounds Li2+xTi3O7, with x<2, maintain the ramsdellite structure, although some important microstructural differences are observed. For example the compound with x=0.55 exhibits an incommensurate modulation (q≈{1}/{3}c*). On the other hand, for Li2+xTi3O7 with x>2, a commensurable a×2b×c cell can be proposed. A close structural relationship between the intercalated compounds and host compound, together with the small changes in the basic ramsdellite cell parameters during the intercalation process, is likely at the origin of the good cycling behavior of a lithium cell using Li2Ti3O7 as the positive electrode.

  3. 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

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 7-Oxabicyclo heptane, 3-ethenyl, 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...

  4. Origin Single-stranded DNA Releases Sld3 Protein from the Mcm27 Complex, Allowing the GINS Tetramer to Bind the Mcm27 Complex*

    PubMed Central

    Bruck, Irina; Kaplan, Daniel L.

    2011-01-01

    The replication fork helicase in eukaryotic cells is comprised of Cdc45, Mcm27, and GINS (CMG complex). In budding yeast, Sld3, Sld2, and Dpb11 are required for the initiation of DNA replication, but Sld3 and Dpb11 do not travel with the replication fork. Sld3 and Cdc45 bind to early replication origins during the G1 phase of the cell cycle, whereas Sld2, GINS, polymerase ϵ, and Dpb11 form a transient preloading complex that associates with origins during S phase. We show here that Sld3 binds tightly to origin single-stranded DNA (ssDNA). CDK-phosphorylated Sld3 binds to origin ssDNA with similar high affinity. Origin ssDNA does not disrupt the interaction between Sld3 and Dpb11, and origin ssDNA does not disrupt the interaction between Sld3 and Cdc45. However, origin ssDNA substantially disrupts the interaction between Sld3 and Mcm27. GINS and Sld3 compete with one another for binding to Mcm27. However, in a mixture of Sld3, GINS, and Mcm27, origin ssDNA inhibits the interaction between Sld3 and Mcm27, whereas origin ssDNA promotes the association between GINS and Mcm27. We also show that origin single-stranded DNA promotes the formation of the CMG complex. We conclude that origin single-stranded DNA releases Sld3 from Mcm27, allowing GINS to bind Mcm27. PMID:21460226

  5. Temperature dependence of superfluid density in YBa 2Cu 3O 7- δ and Y 0.7Ca 0.3Ba 2Cu 3O 7- δ thin films: A doping dependence study of the linear slope

    NASA Astrophysics Data System (ADS)

    Lai, L. S.; Juang, J. Y.; Wu, K. H.; Uen, T. M.; Gou, Y. S.

    2005-11-01

    By using a microstrip ring resonator to measure the temperature dependence of the in-plane magnetic penetration depth λ(T) in YBa2Cu3O7-δ (YBCO) and Y0.7Ca0.3Ba2Cu3O7-δ (Ca-YBCO) epitaxially grown thin films, the linear temperature dependence of the superfluid density ρs/m∗ ≡ 1/λ2(T) was observed from the under- to the overdoped regime at the temperatures below T/Tc ≈ 0.3 . For the underdoped regime of YBCO and Ca-YBCO thin films, the magnitude of the slope d(1/λ2(T))/dT is insensitive to doping, and it can be treated in the framework of projected d-density-wave model. Combining these slope values with the thermal conductivity measurements, the Fermi-liquid correction factor α2 from the Fermi-liquid model, suggested by Wen and Lee, was revealed here with various doping levels.

  6. 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)

  7. Nqrs Data for C8H7ClN2O3 (Subst. No. 1079)

    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. 1079)

  8. Integrated YBa2Cu3O7-x magnetometer for biomagnetic measurements

    NASA Astrophysics Data System (ADS)

    Drung, D.; Ludwig, F.; Müller, W.; Steinhoff, U.; Trahms, L.; Koch, H.; Shen, Y. Q.; Jensen, M. B.; Vase, P.; Holst, T.; Freltoft, T.; Curio, G.

    1996-03-01

    An integrated dc superconducting quantum interference device (SQUID) magnetometer has been fabricated using a YBa2Cu3O7-x-SrTiO3-YBa2Cu3O7-x multilayer process. The magnetometer consists of a 8.3 mm×8.6 mm pickup coil coupled inductively to a small washer-type SQUID with 9 Ω bicrystal junctions via an integrated 101/2-turn input coil. Using simple direct-coupled read-out electronics with additional positive feedback, a noise level of 9.7 fT/√Hz at 1 kHz and 53 fT/√Hz at 1 Hz was measured inside a magnetically shielded room. Due to the low noise level biomagnetic heart and brain signals with high quality and the very weak signals of the peripheral nerve system were recorded.

  9. Fabrication of YBa2Cu3O7-δ superconducting nanofibres by electrospinning

    NASA Astrophysics Data System (ADS)

    Cui, Xue Mei; Lyoo, Won Seok; Son, Won Keun; Park, Dae Hun; Choy, Jin Ho; Lee, Taek Seung; Park, Won Ho

    2006-12-01

    YBa2Cu3O7-δ superconducting nanofibres were successfully fabricated via the electrospinning method in combination with the sol-gel process. The solution was prepared by the sol-gel process with a homogeneous aqueous PVA solution containing Y, Ba, and Cu acetates. The viscosity of the precursor sol for electrospinning was controlled by the evaporation of solvent and a condensation reaction. The electrospun nanofibres were pyrolysed to remove PVA or volatile components, and then sintered to generate a superconducting phase. The critical transition temperature (Tc) of superconducting YBa2Cu3O7-δ nanofibres was measured by DC susceptibility tests. By optimizing the electrospinning process and following heat treatments, superconducting YBa2Cu3O7-δ nanofibres with a Tc = 92.2 K could be produced.

  10. Integrated hybrid treatment for the remediation of 2,3,7,8-tetrachlorodibenzo-p-dioxin.

    PubMed

    Bokare, Varima; Murugesan, Kumarasamy; Kim, Jae-Hwan; Kim, Eun-Ju; Chang, Yoon-Seok

    2012-10-01

    The dioxin isomer 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TeCDD) has been reported as the deadliest compound known to science. Due to its highly recalcitrant nature and low bioavailability, it is stubborn toward bioremediation and chemical treatment. Efforts to degrade it using one single technique have not accomplished the desired results. In this study, we have tried to develop an integrated 2,3,7,8-TeCDD removal process using palladized iron nanoparticles (Pd/nFe) for initial reductive dechlorination under anoxic conditions and subsequent oxidative biomineralization. Using laboratory synthesized Pd/nFe, 2,3,7,8-TeCDD was completely dechlorinated to form the end product dibenzo-p-dioxin (DD). Oxidative degradation of DD was successfully achieved by growing active cells of a dioxin-degrading microorganism Sphingomonas wittichii RW1 (DSM 6014) under aerobic culture conditions. Metabolite identification was done by high performance liquid chromatography (HPLC) and whole cell protein was measured as the indicator for cell growth. To the best of our knowledge, this is the first report on integrated hybrid degradation method for 2,3,7,8-TeCDD. PMID:22909785

  11. 4-Imino-2,7-dimethyl-5,6,7,8-tetra-hydro-4H-1-benzothieno[2,3-d]pyrimidin-3-amine.

    PubMed

    Kalashetti, Mallikarjun B; Fathima, Nikhath; Khan, Ashraf Y; Begum, Noor Shahina; Khazi, I M

    2012-08-01

    In the title compound, C(12)H(16)N(4)S, the fused benzothio-phene and the pyrimidine rings are coplanar [dihedral angle = 1.61 (6)°]. Three C atoms of the cyclohexene ring (at positions 3, 6 and 7) are disordered over two sites with an occupancy ratio of 0.702 (8):0.298 (8). The cyclo-hexene ring in both the major and minor components adopts a half-chair conformation. The crystal structure is stabilized by N-H⋯N and C-H⋯N inter-actions, resulting in the formation of inversion dimers with R(2) (2)(10) and R(2) (2)(12) graph-set motifs. PMID:22904911

  12. 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.

  13. 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.

  14. NIR to visible upconversion emission in Tm3+ doped Na2Y2B2O7 powder phosphor

    NASA Astrophysics Data System (ADS)

    Soni, Abhishek Kumar; Rai, Vineet Kumar

    2015-05-01

    Tm3+ ions doped Na2Y2B2O7 powder phosphor has been synthesized through combustion method. Crystal structure and phase of the prepared sample have been investigated by powder X-ray diffraction (XRD) analysis. Upconversion emission bands in the 400-900 nm range under the excitation of 980nm diode laser have been acquired, and involved upconversion mechanism has been discussed with the help of a suitable energy level diagram. The colour coordinate of developed phosphor has been calculated by CIE chromaticity diagram. Present phosphor can be used in fabrication of upconverting LEDs.

  15. Crystal-field level inversion in lightly Mn-doped Sr3Ru2O7

    SciTech Connect

    Hossain, M. A.; Hu, Z.; Haverkort, M. W.; Burnus, T.; Chang, C. F.; Klein, S.; Denlinger, J. D.; Lin, H.-J.; Chen, C. T.; Mathieu, R.; Kaneko, Y.; Tokura, Y.; Satow, S.; Yoshida, Y.; Takagi, H.; Tanaka, A.; Elfimov, I. S.; Sawatzky, G. A.; Tjeng, L. H.; Damascelli, A.

    2008-01-15

    Sr3(Ru1-xMnx)2O7, in which 4d-Ru is substituted by the more localized 3d-Mn, is studied by x-ray dichroism and spin-resolved density functional theory. We find that Mn impurities do not exhibit the same 4+ valence of Ru, but act as 3+ acceptors; the extra eg electron occupies the in-plane 3dx2-y2 orbital instead of the expected out-of-plane 3d3z2-r2. We propose that the 3d-4d interplay, via the ligand oxygen orbitals, is responsible for this crystal-field level inversion and the material's transition to an antiferromagnetic, possibly orbitally ordered, low-temperature state.

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

    SciTech Connect

    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.

  17. 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.

  18. 40 CFR 180.1086 - 3,7,11-Trimethyl-1,6,10-dodecatriene-1-ol and 3,7,11-trimethyl-2,6,10-dodecatriene-3-ol...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....1086 3,7,11-Trimethyl-1,6,10-dodecatriene-1-ol and 3,7,11-trimethyl-2,6,10-dodecatriene-3-ol; exemption... 40 Protection of Environment 23 2010-07-01 2010-07-01 false 3,7,11-Trimethyl-1,6,10-dodecatriene-1-ol and 3,7,11-trimethyl-2,6,10-dodecatriene-3-ol; exemption from the requirement of a tolerance....

  19. Evolution of the local electronic states in Mn-doped Sr3 Ru2 O7

    NASA Astrophysics Data System (ADS)

    Leshen, Justin; Petryk, Matthew; Giannakis, Ioannis; Trager, Michael; Kavai, Mariam; Singer, Noah; Kaneko, Yoshio; Tokura, Yoshi; Aynajian, Pegor

    2015-03-01

    Thermal and quantum phase transitions have been central to the study of the strongly correlated electron systems. The double layer Sr3Ru2O7 is a particularly interesting candidate for such studies where a few percent of Mn-doping, replacing the Ru atoms, drives the system towards an antiferromagnetic (AFM) Mott insulator. Using scanning tunneling microscopy and spectroscopy we will address the effect of individual Mn dopants on the local electronic density of states in lightly doped Sr3(Ru1-xMnx)2 O7 and investigate the evolution of its electronic states across the paramagnetic metal to AFM Mott insulating phase transition.

  20. DISPOSITION OF 2,3,7,8-TETRABROMODIBENZO-P-DIOXIN AND 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN IN THE RAT: BILIARY EXCRETION AND INDUCTION OF CYTOCHROMES CYP1A1 AND CYP1A2

    EPA Science Inventory

    The biologic activity and pharmacokinetic properties of 2,3,7,8-tetrabromodibenzo-p-dioxin (TBDD) are similar to those of the chlorinated congener, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Metabolism of both compounds appears to be rate-limiting for excretion which is primaril...

  1. 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.

  2. Crystal structure of 2-amino-7,7-dimethyl-5-oxo-4-(pyridin-4-yl)-5,6,7,8-tetrahydro-4 H-chromene-3-carbonitrile hemihydrate

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    The title compound, 2-amino-7,7-dimethyl-5-oxo-4-(pyridin-4-yl)-5,6,7,8-tetrahydro-4 Hchromene-3-carbonitrile was synthesized by multicomponent reaction at room temperature using commercially available urea as inexpensive and environmentally benign organo-catalyst. Its structure was determined by X-ray structure analysis. The crystals are monoclinic, sp. gr. C2/ c, a = 22.010(6), b = 11.0364(10), c = 17.147(4) Å, β = 130.37(4)°, Z = 8, R = 0.0433 for 2377 observed reflections.

  3. Mesoporous CdS-pillared H2Ti3O7 nanohybrids with efficient photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Lin, Bizhou; Zhou, Yi; He, Liwen; Yang, Weiwei; Chen, Yilin; Gao, Bifen

    2015-04-01

    Heterostructured CdS-pillared H2Ti3O7 nanohybrids were prepared by the self-assembly of exfoliated trititanate nanosheets and CdS nanosol particles under the electrostatic interactions. It was revealed that the present nanohybrids were mesoporous with specific surface areas of about 90 m2 g-1. The nanohybrids exhibited high photocatalytic activity and good recurrence stability in the H2 evolution from water splitting. When the preparation molar ratio of H2Ti3O7/CdS was 2:1, the nanohybrid reached a high H2-evolution rate of 1523 μmol h-1 g-1 under a 300 W Xe lamp irradiation, which was 13 times higher than the bare CdS. Apart from the wider spectral responsive range, the superior photocatalytic performance of the nanohybrids was predominantly attributed to the efficient photogenerated charge separation between the trititanate nanosheets and the encapsulated CdS nanoparticles.

  4. Two oxo complexes with tetranuclear [Fe(4)(mu(3)-O)(2)](8+) and trinuclear [Fe(3)(mu(3)-O)](7+) units.

    PubMed

    Cortés, Piedad; Atria, Ana María; Garland, María Teresa; Baggio, Ricardo

    2006-07-01

    Two new oxo complexes, namely hexa-mu(2)-acetato-acetatoaquabis(di-3-pyridylamine)di-mu(3)-oxo-tetrairon(III) chloride monohydrate ethanol 1.25-solvate, [Fe(4)(C(2)H(3)O(2))(7)O(2)(C(10)H(9)N(3))(2)(H(2)O)]Clx1.25C(2)H(6)OxH(2)O, (I), containing a tetranuclear [Fe(4)(mu(3)-O)(2)](8+) unit, and 2-methylimidazolium hexa-mu(2)-acetato-acetatodiaqua-mu(3)-oxo-triiron(III) chloride dihydrate, (C(4)H(7)N(2))[Fe(3)(C(2)H(3)O(2))(7)O(H(2)O)(2)]Clx2H(2)O, (II), with a trinuclear [Fe(3)(mu(3)-O)](7+) unit, are presented. Both structures are formed by two well differentiated entities, viz. a compact isolated cluster composed of Fe(III) ions coordinated to O(2-) and CH(3)CO(2)(-) anions, and an external group formed by a central Cl(-) ion surrounded by different solvent groups to which the anion is bound through hydrogen bonding. In the case of (I), charge balance cannot be achieved within the groups, so the structure is macroscopically ionic; in the case of (II), in contrast, each group is locally neutral owing to the internal compensation of charges. The trinuclear complex crystallizes with the metal cluster, chloride anion and 2-methylimidazolium cation bisected by a crystallographic mirror plane. PMID:16823197

  5. 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

  6. 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...

  7. 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...

  8. 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.

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

    EPA Science Inventory

    The sorption of 14C-labelcd 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) from water by two uncontaminated surface soils from the Times Beach, MO, area was evaluated by using batch shake testing. orption isotherm plots for the soil with the lower fraction organic carbon (foc) were l...

  10. 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 ...

  11. The fabrication of YBa2Cu3O7 thin films by thermal coevaporation in oxygen

    NASA Astrophysics Data System (ADS)

    Wiesmann, H.; Chen, De Huai

    Thin films of YBa2Cu3O7 have been fabricated by the technique of thermal coevaporation in oxygen. Details of the deposition system design and process are presented. Preliminary results are presented for films grown on magnesium oxide substrates. The films are characterized by x ray diffraction and the quality of their superconducting transition.

  12. 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.

  13. 7-Azaindole-3-acetic acid derivatives: potent and selective CRTh2 receptor antagonists.

    PubMed

    Sandham, David A; Adcock, Claire; Bala, Kamlesh; Barker, Lucy; Brown, Zarin; Dubois, Gerald; Budd, David; Cox, Brian; Fairhurst, Robin A; Furegati, Markus; Leblanc, Catherine; Manini, Jodie; Profit, Rachael; Reilly, John; Stringer, Rowan; Schmidt, Alfred; Turner, Katharine L; Watson, Simon J; Willis, Jennifer; Williams, Gareth; Wilson, Caroline

    2009-08-15

    High throughput screening identified a 7-azaindole-3-acetic acid scaffold as a novel CRTh2 receptor antagonist chemotype, which could be optimised to furnish a highly selective compound with good functional potency for inhibition of human eosinophil shape change in whole blood and oral bioavailability in the rat. PMID:19592244

  14. 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN LEVELS IN ADIPOSE TISSUE OF VIETNAM VETERANS

    EPA Science Inventory

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has been detected at levels ranging from 20 to 173 parts per trillion in adipose tissue from three Vietnam veterans who were 'heavily exposed' to Herbicide Orange. Some tissue samples from other Vietnam veterans and from controls also co...

  15. 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

  16. Coherent Quasiparticles with a Small Fermi Surface in Lightly Doped Sr3Ir2O7

    NASA Astrophysics Data System (ADS)

    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.

    2014-12-01

    We characterize the electron doping evolution of (Sr1 -xLax)3Ir2O7 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 3 x /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 Sr3Ir2O7 .

  17. Site-specific electronic structure of the RBa2Cu3O7-y family

    NASA Astrophysics Data System (ADS)

    Merz, M.; Gerhold, S.; Nücker, N.; Kuntscher, C. A.; Burbulla, B.; Schweiss, P.; Schuppler, S.; Chakarian, V.; Freeland, J.; Idzerda, Y. U.; Kläser, M.; Müller-Vogt, G.; Wolf, Th.

    1999-10-01

    With polarization-dependent O 1s near-edge x-ray-absorption spectroscopy on detwinned RBa2Cu3O7-y (R=Y, La, Pr, Nd) and twinned Pr1-zBa2+zCu3O7-y single crystals, the unoccupied electronic structure of the CuO2 planes and CuO3 chains has been investigated. The data underline the exceptional role of Pr among the rare-earth atoms, which leads to the stabilization of the Pr 4f-O 2pπ states, and therefore to the suppression of superconductivity. Estimates of the out-of-plane fraction for these hybrids are discussed. Moreover, upon substitution of Pr by Ba in Pr1-zBa2+zCu3O7-y a shift of the Pr 4f-O 2pπ band to below the Fermi level is indicated, concurrent with a transfer of doped holes back to the Zhang-Rice singlets.

  18. Microwave properties of a Y 0.7Ca 0.3Ba 2Cu 3O 7- δ microstrip ring resonator with various hole concentrations

    NASA Astrophysics Data System (ADS)

    Lai, L. S.; Juang, J. Y.; Wu, K. H.; Uen, T. M.; Lin, J. Y.; Gou, Y. S.

    2004-10-01

    Superconducting ring resonator with a Y 0.7Ca 0.3Ba 2Cu 3O 7- δ ground plane was fabricated by using Y 0.7Ca 0.3Ba 2Cu 3O 7- δ thin film deposited on both sides of a LaAlO 3 (LAO) substrate. The resonator exhibits a high quality factor Q > 10 4 at T < 30 K, and from empirical relation, Tc/ Tc,max = 1 - 82.6( p - 0.16) 2, we obtained the hole concentration p. By controlling the oxygen contents of the ring resonator, the hole concentration p was controlled from 0.218 to 0.088, determined by the empirical relation, in the same film. The temperature dependence of the resonance frequency, f( T), was then systematically studied. By using Chang’s inductive formula and taking a functional form ( λ(5 K)/ λ( T)) 2 = 1 - ( T/ Tc) 2 at T < 0.6 Tc, the London penetration depths λ(5 K) for various oxygen contents at 5 K were obtained, respectively. Finally, it allows us to test the Uemura relation 1/ λ2(5 K) ∝ Tc from the over- to the underdoped regime in the same sample.

  19. Enhanced photoluminescence of Ca2Al2SiO7:Eu3+ by charge compensation method

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Wang, J.; Zhang, M.; Ding, W.; Su, Q.

    2007-09-01

    The effect of compensator on optical properties of Ca2Al2SiO7:Eu3+ is systematically investigated by the X-ray powder diffraction, photo-luminescence (PL) properties and lifetime. It is obviously observed that the PL intensity of Eu3+ under 394 nm excitation increases in the order of Ca1.86Eu0.14Al2SiO7 (CAS), Ca1.72Na0.14Eu0.14Al2SiO7 (CASNa) and Ca1.86Eu0.14Al2.14Si0.86O7 (CASAl), the intensity of Eu3+ are 100%, 134%, 184%, and the lifetime of Eu3+ are 0.75 ms, 1.28 ms and 1.39 ms, respectively. A charge compensation model is proposed to explain the changes in the emission intensity and lifetime of Eu3+ in Ca2Al2SiO7 with different compensation methods.

  20. Magnetic flux relaxation in YBa2Cu3)(7-x) thin film: Thermal or athermal

    NASA Technical Reports Server (NTRS)

    Vitta, Satish; Stan, M. A.; Warner, J. D.; Alterovitz, S. A.

    1991-01-01

    The magnetic flux relaxation behavior of YBa2Cu3O(7-x) thin film on LaAlO3 for H is parallel to c was studied in the range 4.2 - 40 K and 0.2 - 1.0 T. Both the normalized flux relaxation rate S and the net flux pinning energy U increase continuously from 1.3 x 10(exp -2) to 3.0 x 10(exp -2) and from 70 to 240 meV respectively, as the temperature T increases from 10 to 40 K. This behavior is consistent with the thermally activated flux motion model. At low temperatures, however, S is found to decrease much more slowly as compared with kT, in contradiction to the thermal activation model. This behavior is discussed in terms of the athermal quantum tunneling of flux lines. The magnetic field dependence of U, however, is not completely understood.

  1. All-YBa2Cu3O7 trilayer tunnel junctions with Sr2AlTaO6 barrier

    NASA Astrophysics Data System (ADS)

    Ying, Q. Y.; Hilbert, Claude

    1994-12-01

    A new barrier material, Sr2AlTaO6, was employed in fabricating all-YBa2Cu3O7 trilayer tunnel junctions using in situ coevaporation and sputtering deposition. It was found that the superior material properties of Sr2AlTaO6 allow the use of a very thin barrier layer. A dramatic increase in the quasiparticle density of states at the YBa2Cu3O7 superconductive gap was observed for the first time from thin-film all-YBa2Cu3O7 devices. Well-defined gap structures were observed at temperatures up to 47 K. The tunneling characteristics are consistent with the typical superconductor-insulator-superconductor behavior. The temperature dependence of the superconductive gap is compared with the BCS theory.

  2. Studies on Pulsed Laser Deposited YbBa_2Cu_3O_7-x Thin Films

    NASA Astrophysics Data System (ADS)

    Srinivas, S.; Ramachandra Rao, M. S.; Pinto, R.; Bhatnagar, Anil K.

    1998-03-01

    We have deposited high quality YbBa_2Cu_3O_7-x thin films on LaAlO_3<100> substrates using pulsed laser deposition(PLD) method. Films are characterized by XRD, Resistivity, SQUID measurements and surface morphology using Atomic Force Microscopy. We have noticed spiral like growth in a film by AFM. The critical T_co around 88 K and critical current density at zero field is 2x10^6 A/cm^2 at 77 K and SQUID measurement calculations have shown critical current densities as high as 10^7 A/cm^2 at 77K. ( One of the Authors would like to thank UGC-CSIR for financial assistance and is grateful to CSIR for the research support)

  3. Study of superconducting a-axis oriented YBa 2Cu 3O 7-δ thin films deposited on Y 2O 3/YSZ/Si with PrBa 2Cu 3O 7-δ seed layer

    NASA Astrophysics Data System (ADS)

    Rosova, Alica; Chromik, Stefan; Benacka, Stefan; Wuyts, Bart

    1995-02-01

    Epitaxial a-axis oriented YBa 2Cu 3O 7-δ (YBCO) superconducting thin films have been grown by off-axis magnetron sputtering on Y 2O 3/YSZ/Si substrates with PrBa 2Cu 3O 7-δ (PBCO) seed layer. The YBCO thin films were deposited immediately after the on-axis magnetron sputtering of PBCO. XRD analyses show that the a-axis volume fraction for 120 nm thick YBCO films varies with substrate temperature during PBCO deposition and its maximum value is higher than 98%. The TEM study shows the clear dependence between the character of the R- T dependence and the microstructure of our YBCO thin films, which varies with the change of the volume ratio of a-axis to c-maxis oriented YBCO.

  4. 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.

  5. 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).

  6. 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

    ...- - 4- ethyl]amino]- 6-fluoro-1,3,5-triazin-2-yl]amino]phenyl]azo], trisodium salt. 721.5260 Section 721...,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-......

  7. 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

    ...- - 4- ethyl]amino]- 6-fluoro-1,3,5-triazin-2-yl]amino]phenyl]azo], trisodium salt. 721.5260 Section 721...,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-......

  8. Radiolytic degradation of 2,3,7,8-TCDD in artificially contaminated soils

    SciTech Connect

    Hillarides, R.J.; Gray, K.A. ); Guzzetta, J.; Cortellucci, N.; Sommer, C. )

    1994-12-01

    This paper reports results of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) destruction on artificially contaminated soil using cobalt-60 ([sup 60]Co) [gamma] radiation. Important parameters (soil moisture content, surfactant type/concentration, equilibration, and radiation dose) and their optimum ranges are identified. Scavenger (N[sub 2]O, O[sub 2], 2-propanol) studies were conducted to explore the consequences of controlling oxidative and reductive conditions in the soil, and reaction byproducts have been analyzed under selected reaction conditions. A standard soil (EPA SSM-91) was artificially contaminated with 2,3,7,8-TCDD to 100 ppb, and in the presence of 25% water and 2% surfactant (RA-40) and at a high irradiation dose (800 kGy), greater than 92% TCDD destruction was achieved, resulting in a final TCDD concentration of less than 7 ppb. Results of scavenger and byproduct studies and theoretical target theory calculations indicate that TCDD destruction is caused primarily by direct radiation effects and proceeds through reductive dechlorination. 53 refs., 6 figs., 3 tabs.

  9. 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}

  10. Photolithographically patterned thin-film multilayer devices of YBa2Cu3O(7-x)

    NASA Astrophysics Data System (ADS)

    Kingston, J. J.; Wellstood, F. C.; Quan, Du; Clarke, John

    1991-03-01

    Thin-film YBa2Cu3O(7-x) - SrTiO3-YBa2Cu3O(7-x) multilayer interconnect structures in which each in situ laser-deposited film is independently patterned by photolithography have been fabricated. The two key components necessary for a superconducting multilayer interconnect technology have been constructed: crossovers and window contacts. As a further demonstration of the technology, the authors have fabricated a thin-film flux transformer which is suitable for use with a superconducting quantum interference device (SQUID) and includes a ten-turn input coil with 6-micron linewidth. Transport measurements showed that the critical temperature was 87 K and the critical current was 135 micro-A at 82 K.

  11. Photolithographically patterened thin-film multilayer devices of YBa2Cu3O(7-x)

    NASA Astrophysics Data System (ADS)

    Kingston, J. J.; Wellstood, F. C.; Quan, Du; Clarke, J.

    1990-09-01

    We have fabricated thin-film YBa2Cu3O(7-x) SrTiO3YBa2Cu3O(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 micrometer linewidth. Transport measurements showed that the critical temperature was 87K and the critical current was 135 microns A at 82K.

  12. Growth of YBa 2Cu 3O 7-δ on Co implanted substrates

    NASA Astrophysics Data System (ADS)

    Weber, C.; Kahlmann, F.; Schubert, J.; Zander, W.; Kabius, B.; Breuer, U.; Buchal, Ch.

    1997-02-01

    We have studied films of YBa 2Cu 3O 7-δ (YBCO) grown on SrTiO 3 substrates, which were implanted with high doses of Co (1 × 10 16-5 × 10 17 ions/cm 2 at 100 keV). The indirect modification of YBCO by local ion implantation of Co into the substrate is investigated to evaluate the feasibility of a new planar technology for the fabrication of Josephson junctions. The modified YBCO might become a barrier region of a Josephson junction. We found a strong diffusion of the implanted Co ions out of the substrates into the YBCO films during the deposition process, forming YBa 2Cu 3- xCo xO 7-δ. Our EDX and SNMS analyses show that the Co concentration x is homogeneous across the films. YBa 2Cu 3- xCo xO 7-δ is well known to be an excellent barrier material for SNS-type Josephson junctions. Using a 1.4 μm thick photoresist mask, we have locally implanted Co into the substrates to study the lateral diffusion of Co into the YBCO film above the non-implanted region. We performed EDX analysis on cross-sectional TEM samples and found strong lateral diffusion of Co from the implanted substrate within the YBCO film located above the non-implanted region.

  13. 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.

  14. Nonaqueous chemical depth profiling of YBa2Cu3O(7-x)

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

    A nonaqueous solution of Br in absolute ethanol (EtOH) has recently been reported to be effective at removing nonsuperconducting surface species from YBa2Cu3O(7-x) films, leaving the surface close to the ideal stoichiometry. This same etchant is shown here to be an effective bulk etchant in chemical depth profiling through 1-micron-thick films. The Cu remains in the 2 + oxidation state and the stoichiometry, as determined by X-ray photoelectron spectroscopy, is close to ideal and nearly constant throughout the profile, indicating the absence of any large preferential etching effects. The reaction of YBa2Cu3O(7-x) films with HF/EtOH, HCl/EtOH, and I/EtOH solutions is also reported.

  15. Coherent quasiparticles with a small Fermi Surface in lightly doped Sr3Ir2O7

    NASA Astrophysics Data System (ADS)

    de la Torre, Alberto; McKeown Walker, Siobhan; Tamai, Anna; Hunter, Emily; Subedi, Alaska; Kim, Timur; Hoesch, Moritz; Perry, Robin; Georges, Antoine; Baumberger, Felix

    2015-03-01

    We characterize the electron doping evolution of (Sr1-xLax)Ir2O7 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 3 x / 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 Sr3Ir2O7, in stark contrast with underdoped cuprates.

  16. 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 .

  17. 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.

  18. 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.

  19. Multiple Metamagnetic Quantum Criticality in Sr3 Ru2 O7

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    Bilayer strontium ruthenate Sr3 Ru2 O7 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 ΓH, 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.

  20. 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

  1. Synthesis of carbon-14 and deuterium labeled N-nitroso-2 (3',7'-dimethyl-2',6'-octadienyl) aminoethanols

    USGS Publications Warehouse

    Abidi, S.L.; Idelson, A.L.

    1981-01-01

    Methods of preparation of carbon-14 and deuterium labeled N-nitroso-2(3,7-dimethyl-2,6-octadienyl) aminoethanols are described. The primary synthetic method involved alkylation of ethanolamine or ethylglycine with suitable chlorides and subsequent mild nitrosation. Isomeric 14C-nitrosamines were also prepared by selective -cleavage of the di-substituted ethanolamine with nitrous acid.

  2. Colossal Magnetoresistance Without Mn3+/Mn4+ Double Exchange in the Stoichiometric Pyrochlore Tl2Mn2O7

    PubMed

    Subramanian; Toby; Ramirez; Marshall; Sleight; Kwei

    1996-07-01

    Structural analysis from powder neutron and single-crystal x-ray diffraction data for a sample of the Tl2Mn2O7 pyrochlore, which exhibits colossal magnetoresistance (CMR), shows no deviations from ideal stoichiometry. This analysis gives an Mn-O distance of 1.90 angstroms, which is significantly shorter than the Mn-O distances (1.94 to 2.00 angstroms) observed in phases based on LaMnO3 perovskites that exhibit CMR. Both results in Tl2Mn2O7 indicate oxidation states very close to Tl23+Mn24+O7. Thus, Tl2Mn2O7 has neither mixed valence for a double-exchange magnetic interaction nor a Jahn-Teller cation such as Mn3+, both of which were thought to have an important function in CMR materials. An alternate mechanism for CMR in Tl2Mn2O7 based on magnetic ordering driven by superexchange and strong spin-fluctuation scattering above the Curie temperature is proposed here. PMID:8688054

  3. 3,8-Dimethyl-4,7-diaza-deca-3,7-diene-2,9-dione dioxime.

    PubMed

    Achiwawanich, Supakit; Duangtongyou, Tanwawan; Pakawatchai, Chaveng; Siripaisarnpipat, Sutatip

    2010-01-01

    The complete mol-ecule of the title compound, C(10)H(18)N(4)O(2), is generated by a crystallographic inversion centre at the mid-point of the central C-C bond. The two oxime groups have an E configuration. In the crystal, mol-ecules are linked through inter-molecular O-H⋯N hydrogen bonds. PMID:21522645

  4. A novel mutation in Prph2, a gene regulated by Nr2e3, causes retinal degeneration and outer segment defects similar to Nr2e3rd7/rd7 retinas

    PubMed Central

    Nystuen, Arne M.; Sachs, Andrew J.; Yuan, Yang; Heuermann, Laura; Haider, Neena B.

    2014-01-01

    The nmf193 mutant was generated by a large-scale ENU mutagenesis screen and originally described as having a dominantly inherited phenotype characterized by fundus abnormalities. We determined that nmf193 mice exhibit outer segment defects and progressive retinal degeneration. Clinical examination revealed retinal spotting apparent at 6 weeks of age. Histological analysis of homozygous mutant mice at 6 weeks indicated an absence of outer segments (OS) and a 50% reduction of photoreceptor cells which progressed to complete loss of photoreceptors by 10 months. Mice heterozygous for the nmf193 mutation had a less severe phenotype of shortened outer segments at 2 months with progressive loss of photoreceptor cells to 50% by 10 months. A positional cloning approach using a DNA pooling strategy was performed to identify the causative mutation in nmf193 mice. The nmf193 mutation linked to chromosome 17 and fine mapped to an interval containing the peripherin/rds (Prph2) gene. Mutation analysis identified a single base change in Prph2 that causes aberrant splicing between exon 1 and 2. Interestingly, a comparative histological analysis demonstrated that Prph2nmf193/+ mutants have similar photoreceptor degeneration to that of Nr2e3rd7/rd7. We show that Prph2 mRNA and protein levels are reduced in the Nr2e3rd7/rd7 mutant compared to control littermates. Further, chromatin immunoprecipitation analysis shows that Prph2 is a direct target of NR2E3. In addition, the down-regulation of Prph2 gene expression is similar in both the Nr2e3rd7/rd7 and Prph2nmf193/+ mutants suggesting that the reduction of Prph2 may contribute to the degenerative pathology seen in Nr2e3rd7/rd7. PMID:18763016

  5. 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,...

  6. 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,...

  7. NUCLEATION OF YBA(2)CU(3)O(7-D) IN THE BAF(2) PROCESS

    SciTech Connect

    WU,L.; SOLOVYOV,V.F.; WIESMANN,H.J.; ZHU,Y.; SUENAGA,M.

    2001-06-24

    The nucleation of the c-axis aligned and non-c-axis YBa{sub 2}Cu{sub 3}O{sub {approximately}6.1} (YBCO) from precursor films on [001]-cut SrTiO{sub 3} was investigated for the so-called BaF{sub 2} process. Specimens with different thickness were quenched from 735 C, then studied by transmission electron microscopy and x-ray diffraction techniques. Preceding the formation of YBCO nuclei, three intermediate phases of (Y,Ba) oxy-fluoride and a transition phase without F were found in the precursor films. These were structurally and chemically related to the nuclei of YBCO which was found to be deficient in Cu relative to its stoichiometric composition.

  8. Palladium(IV) in an Oxoanionic Environment: The XeF2 Assisted Synthesis of [Pd(S2 O7 )3 ](2.).

    PubMed

    Bruns, Jörn; van Gerven, David; Klüner, Thorsten; Wickleder, Mathias S

    2016-07-01

    For the first time tetravalent palladium is detected, coordinated exclusively by simple oxoanions. Stabilization was achieved by formation of the [Pd(S2 O7 )3 ](2-) complex in which three chelating disulfate groups surround the metal atom. The salt K2 [Pd(S2 O7 )3 ] could only be obtained if the reaction of K2 [PdCl6 ] and neat SO3 was performed in the presence of XeF2 . PMID:27238846

  9. 3,8-Dimethyl-4,7-diaza­deca-3,7-diene-2,9-dione dioxime

    PubMed Central

    Achiwawanich, Supakit; Duangtongyou, Tanwawan; Pakawatchai, Chaveng; Siripaisarnpipat, Sutatip

    2011-01-01

    The complete mol­ecule of the title compound, C10H18N4O2, is generated by a crystallographic inversion centre at the mid-point of the central C—C bond. The two oxime groups have an E configuration. In the crystal, mol­ecules are linked through inter­molecular O—H⋯N hydrogen bonds. PMID:21522645

  10. 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.

  11. 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.

  12. 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

  13. Transition Edge YBa_2Cu_3O_(7-x) Microbolometers for Infrared Staring Arrays

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    A potentially important application of high-temperature superconducting microbolometers is infrared staring arrays. In many such staring arrays, sensitivity is more important than speed of response. Thus, it is desirable to design low-thermal-mass pixels that are thermally isolated from the substrate. To this end, Johnson, et al. at Honeywell have fabricated meander lines of YBa_2Cu_3O_7(-x) (YBCO) sandwiched between layers of Si_3N_4 (SN). The silicon was etched out from under each YBCO meander line to form low-thermal-mass, thermally isolated microbolometers. These devices showed responsivities up to 60 kV/W with a 16 micro-A bias, and a noise equivalent power of 9x10^(-13) W/Hz^(1/2) at 7 Hz with a 5 micro-A bias (neglecting contact noise)...

  14. Thermoluminescence and Mechanoluminescence Properties of Ba2-xMgSi2O7:XCe3+ Phosphors

    NASA Astrophysics Data System (ADS)

    Sao, Sanjay Kumar; Brahme, Nameeta; Bisen, D. P.; Tiwari, Geetanjali

    The Ce3+ doped Ba2MgSi2O7 phosphor is synthesized via high temperature solid state reaction method. The Thermoluminescence (TL) and Mechanoluminescence (ML) analysis presents that the emission of this phosphor is in violet region around 400 nm. It is found that the TL intensity is maximum for 0.05mole Ce3+doping and the TL intensity increases with UV exposure time up to 25 min then decreases for higher UV radiation dose. The ML intensity of Ba2MgSi2O7:Ce3+ is maximum for 0.05 mole Ce3+ doping and it is also observed that ML intensity is increasing approximately linearly with impact velocity.

  15. Sandwich-Geometry YBa(2)Cu(3)O(7-delta)/Au/Nb SNS Devices

    NASA Technical Reports Server (NTRS)

    Foote, Marc C.; Hunt, Brian D.

    1993-01-01

    Superconductor/normal-conductor/superconductor (SNS) devices in which electronically active layers consist of high-temperature superconductor YBa(2)Cu(3)O(7-delta), normal conductor Au, and conventional superconductor Nb, fabricated in sandwich geometry. Devices and processes by which fabricated are part of continuing effort to develop SNS microbridges for use in superconducting quantum interference devices (SQUIDS's) or as mixers or local oscillators operating at frequencies of hundreds of gigahertz. Results show promise for manufacture of practical devices.

  16. 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

  17. Anisotropic transport properties of PrBa 2Cu 3O 7

    NASA Astrophysics Data System (ADS)

    Goto, M.; Takenaka, K.; Eisaki, H.; Uchida, S.

    1997-08-01

    The in-plane resitivity is measured on the twin-free PrBa 2Cu 3O 7 crystals. The observal anisotropy indicates that dominant carrier conduction takes place in the CuO one-dimensional chain. By applying the pressure, ϱa, containing CuO 2 plane contribution increases more rapidly than ϱa, containing both and plane contributions. This is considered to be due to the increased the hybridization between Pr4f and O2p orbital at the plane site, consistent with the scenario proposed by Fehrenbacher and Rice.

  18. 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

  19. Rationale for assessment of risk from exposure to 2,3,7,8-TCDD

    SciTech Connect

    Mukerjee, D.; Stara, J.F.; Schaum, J.L.

    1986-01-01

    The human health risk assessment is supported by methodology for utilizing toxic effects in animals consisting of carcinogenic and noncarcinogenic responses as a result of chronic, subchronic and acute exposures. One of the initial steps in a risk assessment activity involves the estimation of exposure levels. These estimates are typically based on either direct environmental measurements or predictions obtained from fate and transport models. The decision to develop assessment of risk from chronic exposure based on a nonthreshold model is made if a chemical demonstrates carcinogenic activity in animal bioassays and/or in human epidemiological studies. In the absence of any positive human epidemiologic data, it is assumed that a substance which induces a statistically significant carcinogenic response in animals has the probability to cause cancer in humans. The carcinogenic potential of 2,3,7,8-TCDD has been established based on chronic exposure in rodents. In addition, 2,3,7,8-TCDD has also been shown to be a liver cancer promoter in rodents. In the risk assessment on dioxins based on chronic exposure in experimental animals, 2,3,7,8-TCDD is regarded as a carcinogenic substance.

  20. 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.

  1. 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

  2. Sequentially evaporated thin film YBa2Cu3O(7-x) superconducting microwave ring resonator

    NASA Technical Reports Server (NTRS)

    Rohrer, Norman J.; To, Hing Y.; Valco, George J.; Bhasin, Kul B.; Chorey, Chris; Warner, Joseph D.

    1990-01-01

    There is great interest in the application of thin film high temperature superconductors in high frequency electronic circuits. A ring resonator provides a good test vehicle for assessing the microwave losses in the superconductor and for comparing films made by different techniques. Ring resonators made of YBa2Cu3O(7-x) have been investigated on LaAlO3 substrates. The superconducting thin films were deposited by sequential electron beam evaporation of Cu, Y, and BaF2 with a post anneal. Patterning of the superconducting film was done using negative photolithography. A ring resonator was also fabricated from a thin gold film as a control. Both resonators had a gold ground plane on the backside of the substrate. The ring resonators' reflection coefficients were measured as a function of frequency from 33 to 37 GHz at temperatures ranging from 20 K to 68 K. The resonator exhibited two resonances which were at 34.5 and 35.7 GHz at 68 K. The resonant frequencies increased with decreasing temperature. The magnitude of the reflection coefficients was in the calculation of the unloaded Q-values. The performance of the evaporated and gold resonator are compared with the performance of a laser ablated YBa2Cu3O(7-x) resonator. The causes of the double resonance are discussed.

  3. Fe-57 and Sn-119 Moessbauer study of La2CuO(4-y), YBa2Cu3O(7-y) and SmBa2Cu3O(7-y)

    NASA Technical Reports Server (NTRS)

    Jha, S.; Mitros, C.; Yehia, S.; Lahamer, Amer; Julian, Glenn M.

    1988-01-01

    Moessbauer studies reveal antiferromagnetic order in doped La2CuO(4-7): at 77 K, H = 476 kOe at Fe-57 and H is less that 10 kOe at Sn-119. Split-source and conventional absorber experiments on RBa2Cu3O(7-y) (R = Y, Sm) are consistent with occupation of 3 sites by Fe-57, the relative population depending on sample preparation and Fe concentration.

  4. Synthesis and antiviral activity of certain 4-substituted and 2,4-disubstituted 7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3-d]pyrimidines.

    PubMed

    Saxena, N K; Hagenow, B M; Genzlinger, G; Turk, S R; Drach, J C; Townsend, L B

    1988-08-01

    Treatment of the sodium salt of 4-chloro-2-(methylthio)pyrrolo[2,3-d]pyrimidine (2) with (2-acetoxyethoxy)methyl bromide (3) has provided 4-chloro-2-(methylthio)-7[(2-acetoxyethoxy)methyl]pyrrolo[2,3- d]pyrimidine (4). Ammonolysis of 4 at room temperature gave 4-chloro-2-(methylthio)-7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3- d]pyrimidine (5). However, ammonolysis of 5 at 130 degrees C furnished 4-amino-2-(methylthio)-7-[(2-hydroxyethoxy)methyl]-pyrrolo[2,3- d]pyrimidine (6), which on desulfurization with Raney Ni yielded 4-amino-7-[(2-hydroxyethoxy)-methyl]pyrrolo[2,3-d]pyrimidine (7) (acyclic analogue of tubercidin). The oxidation of 6 with m-chloroperbenzoic acid provided the sulfone derivative 8. A nucleophilic displacement of the 2-methylsulfonyl group from 8 with methoxide anion provided 4-amino-2-methoxy-7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3-d]pyrimidine (9). Demethylation of 9 with iodotrimethylsilane gave 4-amino-2-hydroxy-7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3-d]pyrimidine (10). Treatment of 2,4-dichloropyrrolo[2,3-d]pyrimidine (11) with 3 gave the protected acyclic compound 12, which on deacetylation and ammonolysis under controlled reaction conditions gave 2,4-dichloro-7-[(2-hydroxyethoxy)-methyl]pyrrolo[2,3-d]pyrimidine (13) and 4-amino-2-chloro-7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3- d]pyrimidine (14), respectively. The condensation of 2-acetamido-4-chloropyrrolo[2,3-d]pyrimidine (15) with 3 gave the protected acyclic compound 16, which on concomitant deacetylation and ammonolysis with methanolic ammonia at an elevated temperature yielded 2,4-diamino-7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3-d]pyrimidine (17) in moderate yield. In tests involving human cytomegalovirus (HCMV) and herpes simplex virus type 1 (HSV-1), only slight activity and cytotoxicity were observed. The most active compounds (12 and 13) were slightly more active against HCMV than acyclovir, but both compounds were inactive against HSV-1. The activity against HCMV, however, was not well

  5. Synthesis, photoluminescence and Judd-Ofelt parameters of LiNa3P2O7:Eu3+ orthorhombic microstructures

    NASA Astrophysics Data System (ADS)

    Munirathnam, K.; Dillip, G. R.; Raju, B. Deva Prasad; Joo, S. W.; Dhoble, S. J.; Nagabhushana, B. M.; Hari Krishna, R.; Ramesh, K. P.; Varadharaj Perumal, S.; Prakashbabu, D.

    2015-09-01

    We report, for the first time, the photoluminescence properties of Eu3+-doped LiNa3P2O7 phosphor, synthesized by a facile solid-state reaction method in air atmosphere. The crystal structure and phase purity of the phosphors were analyzed by X-ray diffraction analysis. Orthorhombic structural morphology was identified by scanning electron microscopy. The phosphate groups in the phosphor were confirmed by Fourier transform infrared analysis. Bandgap of the phosphor was calculated from the diffuse reflectance spectra data using Kubelka-Munk function. Under 395-nm UV excitation, the phosphors show signs of emitting red color due to the 5D0 → 7F2 transition. In accordance with Judd-Ofelt theory, spectroscopic parameters such as oscillator intensity parameter Ω t ( t = 2), spontaneous emission probabilities, fluorescence branching ratios and radiative lifetimes were calculated and analyzed for the first time in this system.

  6. Frequency dependence of the nonlinear response in YBa2Cu3O7-x transmission lines

    NASA Astrophysics Data System (ADS)

    Mateu, Jordi; Booth, James C.; Moeckly, Brian H.

    2007-01-01

    The authors evaluate the frequency dependence of the nonlinear response in high-temperature superconductor YBa2Cu3O7-x thin films by simultaneously measuring the nonlinear intermodulation products and harmonic generation in broadband superconducting transmission lines at 76K. The frequencies of the two-tone incident signal are set to produce spurious signals from 1to21GHz. They extract a nonlinear term ∣ΔR2+jωΔL2∣ by applying a model of spurious signal generation in superconducting transmission lines to their measurement results. They found that this nonlinear term follows a linear dependence on frequency, indicating a dominant contribution of the nonlinear inductance ΔL2 over the nonlinear resistance ΔR2, (ωΔL2≫ΔR2), for the superconducting nonlinear response.

  7. Nonaqueous chemical etch for YBa2Cu3O(7-x)

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    A nonaqueous chemical etch, with Br as the active ingredient, is described which removes the insulating hydroxides and carbonates that form on high-temperature superconductor surfaces as a result of atmospheric exposure. X-ray photoemission spectra have been recorded before and after etching YBa2Cu3O(7-x) films. It is found that, after the etch, the high binding energy O 1s and Ba 3d peaks associated with surface contaminants are greatly reduced, the Y:Ba:Cu ratio is close to the expected 1:2:3, and the oxidation state of the Cu(2+) is not affected. The resistance of an etched film reaches zero at 78 K, compared to 81 K for a similar unetched film. The suitability of other nonaqueous halogen-based etches is discussed, as is the applicability of this etch to other high-Tc superconductors.

  8. 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

  9. 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

  10. Whole brain 3D T2-weighted BOLD fMRI at 7T

    PubMed Central

    Hua, Jun; Qin, Qin; van Zijl, Peter C. M.; Pekar, James J.; Jones, Craig K.

    2014-01-01

    Purpose A new acquisition scheme for T2-weighted spin-echo BOLD fMRI is introduced. Methods It employs a T2-preparation module to induce BOLD contrast, followed by a single-shot 3D fast gradient-echo readout with short TE. It differs from most spin-echo BOLD sequences in that BOLD contrast is generated before the readout, which eliminates the “dead time” due to long TE required for T2 contrast, and substantially improves acquisition efficiency. This approach, termed “3D T2prep-GRE”, was implemented at 7T with a typical spatial (2.5×2.5×2.5mm3) and temporal (TR=2.3s) resolution for fMRI and whole-brain coverage (55 slices), and compared with the widely used 2D spin-echo EPI sequence. Results In fMRI experiments of simultaneous visual/motor activities, 3D T2prep-GRE showed minimal distortion and little signal dropout across the whole brain. Its lower power deposition allowed greater spatial coverage (55 versus 17 slices with identical TR, resolution and power level), temporal SNR (60% higher) and CNR (35% higher) efficiency than 2D spin-echo EPI. It also showed smaller T2* contamination. Conclusion This approach is expected to be useful for ultra-high field fMRI, especially for regions near air cavities. The concept of using T2-preparation to generate BOLD contrast can be combined with many other sequences at any field strength. PMID:24338901

  11. Disposition of 1,2,3,7,8-pentachlorodibenzofuran in the rat

    SciTech Connect

    Brewster, D.W.; Birnbaum, L.S.

    1988-09-30

    1,2,3,7,8-Pentachlorodibenzofuran (1PeCDF) is one of several toxic polychlorinated dibenzofurans (PCDFs) which are ubiquitous environmental contaminants. Related in structure and toxicity to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), PCDFs have been detected in municipal and industrial effluents, PCB mixtures, and in a variety of antiseptics and preservative solutions. The objective of this study was to evaluate the distribution and elimination of 1PeCDF in the rat and to compare these parameters with that of 2,3,4,7,8-pentachlorodibenzofuran (4PeCDF) and 2,3,7,8-tetrachlorodibenzofuran (TCDF). After iv administration of 0.1 mumol (3H)1PeCDF/kg, 1PeCDF was rapidly cleared from the blood and distributed to the liver, muscle, skin, and adipose tissue in a manner similar to that for other dibenzofurans. The initial pool sizes of 1PeCDF-derived radioactivity in the liver, muscle, skin, and adipose tissue were 43,35,10, and 7% of the administered dose, respectively. In all cases, loss of radioactivity from these tissues could be described by exponential decay and the initial half-lives for these tissues were 1.36, 0.03, 13, and 1 day, respectively. After redistribution from the muscle, skin, and adipose tissues to the liver, 1PeCDF was metabolized to a polar metabolite(s) and excreted from the body via the bile into the feces. No parent compound was detected in the bile and fecal excretion was the major route of elimination. Most of the radioactivity in the urine was excreted within the first day, after which less than 0.5% of the dose/day was detected. More than half of the administered dose was excreted in the urine and feces within 2 days. The whole-body half-life of related compounds is 4PeCDF much greater than 1PeCDF greater than or equal to TCDF.

  12. Epigallocatechin-3-gallate elicits Ca2+ spike in MCF-7 breast cancer cells: essential role of Cav3.2 channels.

    PubMed

    Ranzato, Elia; Magnelli, Valeria; Martinotti, Simona; Waheed, Zeina; Cain, Stuart M; Snutch, Terrance P; Marchetti, Carla; Burlando, Bruno

    2014-10-01

    We used MCF-7 human breast cancer cells that endogenously express Cav3.1 and Cav3.2 T-type Ca(2+) channels toward a mechanistic study on the effect of EGCG on [Ca(2+)]i. Confocal Ca(2+) imaging showed that EGCG induces a [Ca(2+)]i spike which is due to extracellular Ca(2+) entry and is sensitive to catalase and to low-specificity (mibefradil) and high-specificity (Z944) T-type Ca(2+)channel blockers. siRNA knockdown of T-type Ca(2+) channels indicated the involvement of Cav3.2 but not Cav3.1. Application of EGCG to HEK cells expressing either Cav3.2 or Cav3.1 induced enhancement of Cav3.2 and inhibition of Cav3.1 channel activity. Measurements of K(+) currents in MCF-7 cells showed a reversible, catalase-sensitive inhibitory effect of EGCG, while siRNA for the Kv1.1 K(+) channel induced a reduction of the EGCG [Ca(2+)]i spike. siRNA for Cav3.2 reduced EGCG cytotoxicity to MCF-7 cells, as measured by calcein viability assay. Together, data suggest that EGCG promotes the activation of Cav3.2 channels through K(+) current inhibition leading to membrane depolarization, and in addition increases Cav3.2 currents. Cav3.2 channels are in part responsible for EGCG inhibition of MCF-7 viability, suggesting that deregulation of [Ca(2+)]i by EGCG may be relevant in breast cancer treatment. PMID:25260713

  13. YBa2Cu3O7-δ superconducting films prepared by low pressure post-annealing

    NASA Astrophysics Data System (ADS)

    Wang, Lianhong; Liu, Chong; Fan, Jing

    2014-12-01

    YBa2Cu3O7-δ precursor films are deposited on 2″ LaAlO3 wafer by the co-evaporation technique using Y, BaF2 and Cu as evaporation sources. After deposition, the films are annealed at low-pressure atmosphere with the composition of oxygen and water vapour. Compared with the normal pressure annealing, it is shown that low pressure can greatly improve the superconducting properties of 2″ YBCO films with thickness larger than 500 nm, as the microcrack on films surface becomes unobservable the microwave surface resistance is greatly reduced. Furthermore, it is also revealed that the optimal processing window for making high quality superconducting YBCO films through ex-situ process is relatively small, therefore the ambient in annealing furnace is crucial important and should be precisely controlled.

  14. Conductor-backed coplanar waveguide resonators of YBa2Cu3O(7-delta) on LaAlO3

    NASA Technical Reports Server (NTRS)

    Miranda, Felix A.; Bhasin, Kul B.; Kong, Keon-Shik; Itoh, Tatsuo; Stan, Mark A.

    1992-01-01

    Conductor-backed coplanar waveguide (CBCPW) resonators operating at 10.8 GHz have been fabricated from laser ablated and off-axis magnetron sputtered YBa2Cu3O(7-delta) (YBCO) high-temperature superconducting (HTS) thin films on LaAlO3. These resonators were tested in the temperature range from 14 to 92 K. The unloaded quality factor at 77 K of the HTS CBCPW resonators was 3 to 4 times that of a similar gold resonator. To the authors' knowledge, these results represent the first reported measurements of HTS-based CBCPW resonators.

  15. 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.

  16. 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.

  17. Conversion of Y3(Al,Ga)5O12:Tb3+ to Y2Si2O7:Tb3+ thin film by annealing at higher temperatures

    NASA Astrophysics Data System (ADS)

    Yousif, A.; Swart, H. C.; Ntwaeaborwa, O. M.; Coetsee, E.

    2013-04-01

    Y3(Al,Ga)5O12:Tb thin films were grown on Si(1 0 0) substrates in an Ar working atmosphere by using the pulsed laser deposition (PLD) technique. The Y3(Al,Ga)5O12:Tb target was ablation deposited onto a Si(1 0 0) substrate using a 266 nm Nd:YAG laser. The influence of post deposition annealing temperature (1073 K to 1473 K) on the excitation and the emission bands, and the crystal structure of the thin film were monitored. X-ray diffraction (XRD) and photoelectron spectroscopy (XPS) depth profiles of the thin films indicate that there were annealing induced changes in the crystal structure and chemical composition causing changes in the excitation bands. These changes (structure and composition) are attributed to interdiffusion of atomic species between the substrate and the Y3(Al,Ga)5O12:Tb3+ thin film. The XRD and XPS data confirm that after annealing, Y3(Al,Ga)5O12:Tb3+ was converted to Y2Si2O7:Tb3+. A change in the relative ratios of the excitation band intensities was measured. Atomic force microscopy (AFM) showed that topographical changes also occurred during the annealing process. Thermoluminescence (TL) glow curves of the Y3(Al,Ga)5O12:Tb3+ thin films before and after annealing, indicated the presence of different types of traps resulting from the change on the structure of the thin films.

  18. Preparation of the YBa 2Cu 3O 7- x powders by emulsion drying method

    NASA Astrophysics Data System (ADS)

    Um, Woo Sik; Kim, Ho Gi

    1989-12-01

    The superconducting powders of YBa 2Cu 3O 7- x were easily prepared from water-in oil type emulsion by loading the yttrium, barium, and copper ions into the aqueous phase. The superconducting orthorhombic phase was formed by calcining at 750°C for 10 h in O 2. The size of the superconducting phase powders was submicron. The density of the sintered specimen using this powders was about 95% of the theoretical density and the resistance sharply decreases at transition temperature.

  19. Digital logic with YBa sub 2 Cu sub 3 O sub 7 minus x dc SQUIDs

    SciTech Connect

    Schwarzbek, S.M.; Davidheiser, R.A.; Fischer, G.R.; Luine, J.A.; Schneier, N.J. )

    1991-08-12

    We report the operation of AND, EXOR, EXNOR, and inverting gates in a circuit architecture suitable for the set of all Boolean gates. Series arrays of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} dc superconducting quantum interference devices with integrated coils exhibit sufficient modulation to allow low-speed tests demonstrating gate logic, and lack of oscillation or latching. The best inverter operated (without load) at 36 {mu}V, with 2 nW of gate dissipation.

  20. Selectivity optimization of substituted 1,2,3-triazoles as α7 nicotinic acetylcholine receptor agonists.

    PubMed

    Arunrungvichian, Kuntarat; Fokin, Valery V; Vajragupta, Opa; Taylor, Palmer

    2015-08-19

    Three series of substituted anti-1,2,3-triazoles (IND, PPRD, and QND), synthesized by cycloaddition from azide and alkyne building blocks, were designed to enhance selectivity and potency profiles of a lead α7 nicotinic acetylcholine receptor (α7-nAChR) agonist, TTIn-1. Designed compounds were synthesized and screened for affinity by a radioligand binding assay. Their functional characterization as agonists and antagonists was performed by fluorescence resonance energy transfer assay using cell lines expressing transfected cDNAs, α7-nAChRs, α4β2-nAChRs, and 5HT3A receptors, and a fluorescence cell reporter. In the IND series, a tropane ring of TTIn-1, substituted at N1, was replaced by mono- and bicyclic amines to vary length and conformational flexibility of a carbon linker between nitrogen atom and N1 of the triazole. Compounds with a two-carbon atom linker optimized binding with Kd's at the submicromolar level. Further modification at the hydrophobic indole of TTIn-1 was made in PPRD and QND series by fixing the amine center with the highest affinity building blocks in the IND series. Compounds from IND and PPRD series are selective as agonists for the α7-nAChRs over α4β2-nAChRs and 5HT3A receptors. Lead compounds in the three series have EC50's between 28 and 260 nM. Based on the EC50, affinity, and selectivity determined from the binding and cellular responses, two of the leads have been advanced to behavioral studies described in the companion article (DOI: 10.1021/acschemneuro.5b00059). PMID:25932897

  1. 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...

  2. 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,...

  3. 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,...

  4. 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,...

  5. 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.

  6. Progress towards all-chemical superconducting YBa2Cu3O7-coated conductors

    NASA Astrophysics Data System (ADS)

    Obradors, X.; Puig, T.; Pomar, A.; Sandiumenge, F.; Mestres, N.; Coll, M.; Cavallaro, A.; Romà, N.; Gázquez, J.; González, J. C.; Castaño, O.; Gutierrez, J.; Palau, A.; Zalamova, K.; Morlens, S.; Hassini, A.; Gibert, M.; Ricart, S.; Moretó, J. M.; Piñol, S.; Isfort, D.; Bock, J.

    2006-03-01

    Chemical solution deposition (CSD) has recently emerged as a very competitive technique for obtaining epitaxial films of high quality with controlled nanostructure. In particular, the all-CSD approach is considered to be one of the most promising approaches for cost-effective production of second-generation superconducting wires. The trifluoroacetate (TFA) route is a very versatile route for achieving epitaxial YBa2Cu3O7 (YBCO) layers with high critical currents. In this work, recent advances towards improvement of the performance of several conductor architectures based on the YBCO TFA process will be presented. We show that new improved anhydrous TFA precursors allow a significant shortening of the pyrolysis time (~1.5 h), and we have increased the total film thickness in a single deposition using polymeric additives. On the other hand, further understanding of the YBCO nucleation and growth process has allowed us to obtain a controlled microstructure and high critical currents (Jcap4-5 MA cm-2 and Icap300 A cm-1 width at 77 K). The growth conditions (CSD) and post-processing conditions (sputtering and CSD) for the underlying oxide cap and buffer layers (CeO2, BaZrO3, SrTiO3, La2Zr2O7, (La,Sr)MnO3) and of self-organized nanostructures (CeO2, BaZrO3) deposited by CSD have been investigated to obtain high-quality interfaces in multilayered systems. Different single-crystal or metallic substrates (YSZ-IBAD (yttrium stabilized zirconia-ion beam assisted deposition) and Ni-RABiT (rolling assisted biaxial texturing)) have been investigated and long (ap10 m) CSD biaxially textured buffers (CeO2, La2Zr2O7) have been grown on Ni-RABiT substrates using a reel-to-reel system. High-performance TFA-YBCO-coated conductors have been obtained on vacuum-based buffer layers (Icap140 A cm-1 width) and on CSD buffer layers grown on IBAD YSZ-SS (stainless steel) substrates. Finally, we report on recent analysis of the magnetic granularity and vortex pinning properties of TFA

  7. 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

  8. AC Josephson effect in YBa 2Cu 3O 7-δ bicrystal grain boundary junctions

    NASA Astrophysics Data System (ADS)

    Fischer, Gerd M.; Andreev, Alexey V.; Divin, Yuri Ya.; Freltoft, Thorsten; Mygind, Jesper; Pedersen, Niels F.; Shen, Yueqiang; Vase, Per

    1994-02-01

    The ac Josephson effect in YBa 2Cu 3O 7-δ bicrystal grain boundary junctions was studied in the temperature range from 4K to 90K. Junctions with widths from 0.2 to 50 μm were made on SrTiO 3 bicrystal substrates by laser ablation and e-beam lithography. The linewidth of the Josephson oscillations is derived from the shape of the dc voltage response to low-intensity, f = 70 GHz radiation at voltages V ≃ ( {h}/{2e}) f , assuming the RSJ model. The effect of the size on the Josephson behavior of this type of high-T c junctions was studied. Close to T c the linewidth of the Josephson oscillations was shown to be determined by thermal fluctuations.

  9. Molecular doping of regioregular poly(3-hexylthiophene) layers by 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane investigated by infrared spectroscopy and electrical measurements

    NASA Astrophysics Data System (ADS)

    Tadaki, Daisuke; Ma, Teng; Zhang, Jinyu; Iino, Shohei; Hirano-Iwata, Ayumi; Kimura, Yasuo; Niwano, Michio

    2015-09-01

    Molecular doping is a charge-transfer process intended to improve the performance of organic electronic devices such as organic transistors. We have investigated molecular doping of regioregular poly(3-hexylthiophene) (P3HT) layers by 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) using infrared absorption spectroscopy in the multiple internal reflection geometry (MIR-IRAS) and conductivity measurements. IRAS data confirm that F4-TCNQ acts as an effective p-type dopant for P3HT; highly doped P3HT displayed an intense, broad absorption band due to polaron (“polaron band”) and a high carrier (hole) density which are indicative of the charge transfer between F4-TCNQ and P3HT. We demonstrate that the charge (hole) transferred from the dopant molecule is distributed along the P3HT polymer chain and spreads over at least 10 thiophene monomer units on the chain. From a comparison of the measured conductivity of F4-TCNQ-doped P3HT layers with the carrier density, we show that the carrier mobility is proportional to the concentration of carriers (holes), which suggests that F4-TCNQ doping induces the conformational change of P3HT polymer chains to enhance the mobility of holes in the films of the doped P3HTs.

  10. YBa2Cu3O7 thin films on nanocrystalline diamond films for HTSC bolometer

    NASA Technical Reports Server (NTRS)

    Cui, G.; Beetz, C. P., Jr.; Boerstler, R.; Steinbeck, J.

    1993-01-01

    Superconducting YBa2Cu3O(7-x) films on nanocrystalline diamond thin films have been fabricated. A composite buffer layer system consisting of diamond/Si3N4/YSZ/YBCO was explored for this purpose. The as-deposited YBCO films were superconducting with Tc of about 84 K and a relatively narrow transition width of about 8 K. SEM cross sections of the films showed very sharp interfaces between diamond/Si3N4 and between Si3N4/YSZ. The deposited YBCO film had a surface roughness of about 1000 A, which is suitable for high-temperature superconductive (HTSC) bolometer fabrication. It was also found that preannealing of the nanocrystalline diamond thin films at high temperature was very important for obtaining high-quality YBCO films.

  11. New 3-Cyano-2-Substituted Pyridines Induce Apoptosis in MCF 7 Breast Cancer Cells.

    PubMed

    Malki, Ahmed; Mohsen, Mona; Aziz, Hassan; Rizk, Ola; Shaban, Omima; El-Sayed, Mohamed; Sherif, Zaki A; Ashour, Hayam

    2016-01-01

    The synthesis of new 3-cyano-2-substituted pyridines bearing various pharmacophores and functionalities at position 2 is described. The synthesized compounds were evaluated for their in vitro anti-cancer activities on five cancer cell lines using 5-FU as reference compound. The results revealed that the benzohydrazide derivative 9a induced growth inhibition in human breast cancer cell line MCF-7 with an IC50 value of 2 μM and it showed lower cytotoxicity on MCF-12a normal breast epithelial cells. Additionally, 9a induced apoptotic morphological changes and induced apoptosis in MCF-7 in a dose and time-dependent manner according to an enzyme linked immunosorbent apoptosis assay which is further confirmed by a TUNEL assay. Flow cytometric analysis indicated that 9a arrested MCF-7 cells in the G1 phase, which was further confirmed by increased expression of p21 and p27 and reduced expression of CDK2 and CDK4. Western blot data revealed significant upregulation of the expression of p53, Bax, caspase-3 and down-regulation of Bcl-2, Mdm-2 and Akt. Additionally, 9a increased the release of cytochrome c from mitochondria to cytoplasm which provokes the mitochondrial apoptotic pathway while it showed no significant change on the expression of the death receptor proteins procaspase-8, caspase-8 and FAS. Furthermore, 9a reduced the expression of phospho AKT and β-catenin in dose dependent manner while inhibiting the expression of migration-related genes such as matrix metalloproteinase (MMP)-9 and vascular endothelial growth factor (VEGF). Our findings suggest that compound 9a could be considered as a lead structure for further development of more potent apoptosis inducing agents with anti-metastatic activities. PMID:26901182

  12. Flux pinning in neutron irradiated YBa sub 2 Cu sub 3 O sub 7 minus x

    SciTech Connect

    Lessure, H.A.; Simizu, S.; Baumert, B.A.; Sankar, S.G.; McHenry, M.E. ); Maley, M.P.; Cost, J.R.; Willis, J.O. )

    1991-03-01

    This paper reports on identical polycrystalline samples of YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} irradiated with fast neutrons (E {gt} 0.1 MeV) in eight steps between 0 and 2.1 {times} 10{sup 18} n/cm{sup 2}. Notable irradiation effects include a T{sub c} depression of nearly 2 K at the highest fluence and large improvement in the critical current density for fields from 0-9 T and temperatures between 4-80 K. Critical currents approaching 2 {times} 10{sup 7} A/cm{sup 2} are observed for optimally irradiated materials at 5K (in zero field) while at 77 K, J{sub c} (O kOe) approaches 5 {times} 10{sup 5} A/cm{sup 2}. Irradiation is seen to take a nearly equilibrium magnetization curve at 77 K and broaden it to a significantly hysteretic curve. A substantial shift in the effective pinning potential as a function of current density is inferred from magnetic relaxation measurements at H = 1T. This is the first such measurement in which systematically increased activation energies for flux creep (as a function of current density) are noted.

  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. 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.

  15. Ten Ghz YBa2Cu3O(7-Delta) Superconducting Ring Resonators on NdGaO3 Substrates

    NASA Technical Reports Server (NTRS)

    To, H. Y.; Valco, G. J.; Bhasin, K. B.

    1993-01-01

    YBa2Cu3O(7-delta) thin films were formed on NdGaO3 substrates by laser ablation. Critical temperatures greater than 89 K and critical current densities exceeding 2 x 10(exp 8) Acm(sub -2) at 77 K were obtained. The microwave performance of films patterned into microstrip ring resonators with gold ground planes was measured. An unloaded quality factor six times larger than that of a gold resonator of identical geometry was achieved. The unloaded quality factor decreased below 70 K for both the superconducting and gold resonators due to increasing dielectric losses in the substrate. The temperature dependence of the loss tangent of NdGaO3 was extracted from the measurements.

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

    DOE PAGESBeta

    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

  17. 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.

  18. Biaxially aligned YBa 2Cu 3O 7-x thin film tapes

    NASA Astrophysics Data System (ADS)

    Iijima, Yasuhiro; Tanabe, Nobuo; Ikeno, Yoshimitsu; Kohno, Osamu

    1991-12-01

    We report the formation of biaxially oriented films of yttorium-stabilized ZrO 2 (YSZ) on a polycrystalline, Ni-based alloy (Hastelloy c276) by Ion-Beam-Assisted Deposition (IBAD), and the subsequent a-b plane aligned YBa 2Cu 3O 7-x (YBCO) films deposited by laser ablation. Jc of 6.0×10 4 A/cm 2 (77 K, O T) and 1.4×10 4 A/cm 2 (77 K, 0.6 T) were obtained. A new method to prevent intergranular-weak-links has been developed for application of oxide superconducting thin films, for tape-shaped cables, magnets, magnetic shields, microwave devices, etc.

  19. Transmission Electron Microscope Study on Electrodeposited Gd2O3 and Gd2Zr2O7 Buffer Layers forYBa2Cu307-..delta.. Superconductors

    SciTech Connect

    Zhao, W.; Norman, A.; Phok, S.; Bhattacharya, R.

    2008-01-01

    We have investigated the microstructures of electrodeposited Gd{sub 2}O{sub 3} (GO) and Gd{sub 2}Zr{sub 2}O{sub 7} (GZO) buffer layers for YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) superconductors with conventional transmission electron microscopy (TEM). A high density of nanoscale voids was present in the GZO buffer layers. No voids were observed in GO buffer layers grown on GZO. YBCO superconductor grown on the GO/GZO buffer layer structure produced a critical current density (J{sub c}) of 3.3 x 10{sup 6} A/cm{sup 2} at 77 K in zero field.

  20. 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.

  1. A novel radioligand for the ATP-gated ion channel P2X7: [3H] JNJ-54232334.

    PubMed

    Lord, Brian; Ameriks, Michael K; Wang, Qi; Fourgeaud, Lawrence; Vliegen, Maarten; Verluyten, Willy; Haspeslagh, Pieter; Carruthers, Nicholas I; Lovenberg, Timothy W; Bonaventure, Pascal; Letavic, Michael A; Bhattacharya, Anindya

    2015-10-15

    The ATP-gated ion channel P2X7 has emerged as a potential central nervous system (CNS) drug target based on the hypotheses that pro-inflammatory cytokines such as IL-1β that are released by microglia, may contribute to the etiology of various disorders of the CNS including depression. In this study, we identified two closely related P2X7 antagonists, JNJ-54232334 and JNJ-54140515, and then tritium labeled the former to produce a new radioligand for P2X7. JNJ-54232334 is a high affinity ligand for the rat P2X7 with a pKi of 9.3±0.1. In rat cortical membranes, [3H] JNJ-54232334 reached saturable binding with equilibrium dissociation (Kd) constant of 4.9±1.3 nM. The compound displayed monophasic association and dissociation kinetics with fast on and off rates. In rat brain sections, specific binding of [3H] JNJ-54232334 was markedly improved compared to the previously described P2X7 radioligand, [3H] A-804598. In P2X7 knockout mouse brain sections, [3H] A-804598 bound to non-P2X7 binding sites in contrast to [3H] JNJ-54232334. In rat or wild type mouse brain sections [3H] JNJ-54232334 bound in a more homogenous and region independent manner. The ubiquitous expression of P2X7 receptors was confirmed with immunohistochemistry in rat brain sections. The partial displacement of [3H] A-804598 binding resulted in the underestimation of the level of ex vivo P2X7 occupancy for JNJ-54140515. Higher levels of P2X7 ex vivo occupancy were measured using [3H] JNJ-54232334 due to less non-specific binding. In summary, we describe [3H] JNJ-54232334 as a novel P2X7 radioligand, with improved properties over [3H] A-804598. PMID:26386289

  2. Tilt grain boundaries in YBa sub 2 Cu sub 3 O sub 7-x thin films

    SciTech Connect

    Gao, Y.; Bai, G.; Chang, H.L.M.; Merkle, K.L.; Lam, D.J.

    1990-07-01

    Grain boundaries in YBa{sub 2}Cu{sub 3}O{sub 7-x} superconductor thin films grown on (001) MgO by metal-organic chemical vapor deposition (MOCVD) have been characterized using transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). It was found that the YBa{sub 2}Cu{sub 3}O{sub 7-x} thin films were highly textured with the c axes, or (001) orientation, nearly parallel between grains and perpendicular to the MgO substrate. A majority of the grain boundaries are low-angle boundaries with a tilt angle, {theta}, less than 15{degree}. The low-angle boundaries appear to be strongly faceted on an atomic scale in such a way that the boundary planes tend to be parallel to the (100), (010), or (110) lattice planes in one of the adjacent grains. Almost all of the lattice planes, except for a number of distorted regions along the boundaries, are continuous across the boundaries from one grain to another, accommodating the misorientation with a slight bending of the lattice planes. The small-angle boundaries are shown to consist of arrays of dislocations. A domain structure, formed by the interchange of a and b axes has been observed in large grains. The domain boundaries are strongly faceted with the (100) and (010) lattice planes parallel to the boundaries. These observations on the atomic structure of boundaries, are used to discuss the effect of grain boundaries on superconductor properties in YBa{sub 2}Cu{sub 3}O{sub 7-x} thin films. 15 refs., 9 figs.

  3. 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.

  4. Anisotropic vortex lattice in YBa[sub 2]Cu[sub 3]O[sub 7

    SciTech Connect

    Yethiraj, M.; Mook, H.A.; Wignall, G.D.; Cubitt, R.; Forgan, E.M.; Lee, S.L.; Paul, D.M.; Armstrong, T. Superconductivity Research Group, University of Birmingham, Birmingham B15 2TT Physik-Institut der Universitaet Zuerich, Schoenberggasse 9, CH 8001, Zuerich Department of Physics, University of Warwick, Coventry CV4 7AL Allied Signal Research Laboratories, Torrance, California 90509 )

    1993-11-01

    We report on small angle neutron scattering observations of the flux line lattice (FLL) in a single crystal of YBa[sub 2]Cu[sub 3]O[sub 7]. To probe the mass anisotropy ratio, [ital m][sub 3]/[ital m][sub 1], measurements were made as a function of angle, [Theta], between the 8 kOe applied field and the crystallographic (001) axis for 0[degree][le][Theta][le]80[degree]. With the rotation about an [ital a]/[ital b] (or [ital y]) axis, two symmetry-related distorted hexagonal FLL domains formed. Contrary to theoretical prediction, the lattices formed are consistent with a rotation of the short basis vector, [bold a][sub 1], from the [ital x] axis by 15[degree], after the effects of anisotropy are removed. The mass ratio is 20[plus minus]2, which is slightly lower than published values. The temperature dependence of the intensity is not conventional.

  5. Synthesis, microstructure and magnetic properties of Fe3Si0.7Al0.3@SiO2 core-shell particles and Fe3Si/Al2O3 soft magnetic composite core

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Fan, Xi'an; Wu, Zhaoyang; Li, Guangqiang

    2015-11-01

    Fe3Si0.7Al0.3@SiO2 core-shell particles and Fe3Si/Al2O3 soft magnetic composite core have been synthesized via a modified stöber method combined with following high temperature sintering process. Most of conductive Fe3Si0.7Al0.3 particles could be uniformly coated by insulating SiO2 using the modified stöber method. The Fe3Si0.7Al0.3@SiO2 core-shell particles exhibited good soft magnetic properties with low coercivity and high saturation magnetization. The reaction 4Al+3SiO2=2α-Al2O3+3Si took place during the sintering process. As a result the new Fe3Si/Al2O3 composite was formed. The Fe3Si/Al2O3 composite core displayed more excellent soft magnetic properties, better frequency stability at high frequencies, much higher electrical resistivity and lower core loss than the pure Fe3Si0.7Al0.3 core. The method of introducing insulating layers surrounding magnetic particles provides a promising route to develop new and high compact soft magnetic materials with good magnetic and electric properties.

  6. Interband transitions in YBa{sub 2}Cu{sub 3}O{sub 7}

    SciTech Connect

    Kircher, J.; Humlicek, J.; Garriga, M.; Cardona, M.; Fuchs, D.; Habermeier, H.U.; Fang, Y.; Welp, U.; Vandervoort, K.; Crabtree, G.

    1991-08-01

    Using rotating analyzer ellipsometry, we have measured all three components of the dielectric tensor of YBa{sub 2}CU{sub 3}O{sub 7} from near-infrared to vacuum-ultraviolet (0.7 -- 24 eV). In the low energy region the spectra for a -- b polarization can be well modelled by a Drude free-carrier response with a frequency independent scattering rate. Below 10 eV we observe strongly anisotropic interband transitions involving the partially filled valence band and the conduction band. At higher energies the anisotropy becomes smaller. In that region we see two prominent double structures around 16 eV and 20 eV that we assign to transitions from lower lying bands with O s and Ba p character to states dose to the Fermi level.

  7. Structural defects in trifluoroacetate derived YBa2Cu3O7 thin films

    NASA Astrophysics Data System (ADS)

    Gazquez, J.; Coll, M.; Roma, N.; Sandiumenge, F.; Puig, T.; Obradors, X.

    2012-06-01

    We present an accurate description of the structural defects occurring within YBa2Cu3O7 (YBCO) films grown by chemical solution deposition (CSD) based on metal trifluoroacetates (TFA). Transmission electron microscopy (TEM) is the essential tool to identify and evaluate the microstructural defects that might act as natural pinning centers. Our study of TFA-YBCO thin films shows that the YBCO thin films contain a variety of extended defects, such as intergrowths, twin boundaries and dislocations, mainly in the basal plane. These extended defects and their interaction make up a rich variety of key microstructural features that play an important role in the YBCO thin films physical properties and performance.

  8. Addition of Iridium to the Biopolymer Mediated Synthesis of YBa2Cu3O7 δ

    NASA Astrophysics Data System (ADS)

    Wimbush, Stuart C.; Marx, Werner; Barth, Andreas; Hall, Simon R.

    This work represents the first study into the addition of iridium into the solgel synthesis of the high temperature superconductor YBa2Cu3O7δ (Y123). Through a biopolymermediated synthetic approach, the homogeneous nature of the precursor sol and the preferred nucleation and growth of Y123 phases allow for a high yield of superconducting nanoparticles with no suppression of the superconducting critical temperature, even at high levels (40 wt%) of iridium addition. We attribute this to iridium not substituting into the Y123 crystal lattice, instead forming an associate phase.

  9. 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

  10. Joint of REBa2Cu3O7-δ Coated Conductors Using Metal Organic Deposition

    NASA Astrophysics Data System (ADS)

    Hiramatsu, K.; Teranishi, R.; Yamada, K.; Sato, Y.; Kaneko, K.

    Joint techniques connecting REBa2Cu3O7-δ(REBCO) coated conductors (CCs) are required to fabricate long length CCs and to repair locally damaged one. Two pieces of REBCO CC were attempted to be jointed using a metal organic deposition (MOD) method. The starting solution for YBCO layer was coated on GdBCO layer of CCs and calcined to fabricate precursor films, two of which were stuck together in a face to face manner, and then these films were pressurized and crystallized to joint them. Two CCs were successfully jointed together with c-axis oriented YBCO without pores and reacted phases at the joint interface.

  11. 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.

  12. 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.

  13. 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}.

  14. Inelastic-neutron-scattering study of the Er3+ energy levels in ErBa2Cu3O7

    NASA Astrophysics Data System (ADS)

    Soderholm, L.; Loong, C.-K.; Kern, S.

    1992-05-01

    Magnetic excitation spectra of ErBa2Cu3O7 have been measured by use of inelastic neutron scattering. Optimal experimental conditions allow the resolution of the transitions between the Er3+ ground state and all seven excited states within the 4I15/2 Russell-Saunders ground multiplet. The data are analyzed in terms of an intermediate-coupling crystal-field model, calculated using spherical-tensor techniques. Calculated spectra based on the results of this analysis are consistent with all experimental spectra, including those obtained at higher temperatures. The eigenfunctions and eigenvalues obtained from this analysis are used to calculate the magnetic properties expected of Er3+ in this crystal environment.

  15. 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.

  16. Studies on white light emission of Sr2MgSi2O7 doped with Dy3+ phosphors

    NASA Astrophysics Data System (ADS)

    Shrivastava, Ravi; Kaur, Jagjeet; Dash, Manoranjan

    2015-06-01

    Present paper reports the preparation of Sr2MgSi2O7 doped with Dy3+ ions by modified high temperature solid state reaction technique. Samples were prepared for different concentration of Dy3+ (0.5, 1.0, 1.5, 2.0 and 2.5 mol%). Sample with optimum photoluminescence intensity was characterized by X-ray diffraction (XRD) technique. Observed XRD spectrum matched with crystallographic open database card specifically appeared for Sr2MgSi2O7 phosphor. This is a confirmation of proper preparation of the sample. Photoluminescence studies of these samples were done. Emission spectra exhibited 5 prominent peaks at 480, 490, 575, 590 and 660 nm respectively. In this case Dy3+ acts as an activator. Peaks centered at 480 and 490 nm are due to the transition 4F9/2 → 6H15/2 (blue color) of Dy3+ ions occupied at different sites. Similarly 575 and 590 nm peaks are originated due to transition 4F9/2 → 6H13/2 (yellow-orange color) of Dy3+ ions occupied at different sites. Emission at 660 nm is due to transition 4F9/2 → 6H11/2 (red color). CIE coordinates have been calculated for each sample and its value exhibited that, overall emission is near white light. In order to investigate the suitability of the samples as white color light sources for industrial uses, correlated color temperature (CCT) and color rendering index (CRI) were calculated. Values of CCT and CRI were found, well within the defined acceptable range.

  17. Origin of paramagnetic magnetization in field-cooled YBa2Cu3O7-δ films

    NASA Astrophysics Data System (ADS)

    Luzhbin, D. A.; Pan, A. V.; Komashko, V. A.; Flis, V. S.; Pan, V. M.; Dou, S. X.; Esquinazi, P.

    2004-01-01

    Temperature dependences of the magnetic moment have been measured in YBa2Cu3O7-δ thin films over a wide magnetic-field range (5⩽H⩽104 Oe). In these films a paramagnetic signal known as the paramagnetic Meissner effect has been observed. The experimental data in the films, which have strong pinning and high critical current densities (Jc˜2×106 A/cm2 at 77 K), are shown to be highly consistent with the theoretical model proposed by Koshelev and Larkin [Phys. Rev. B 52, 13 559 (1995)]. This finding indicates that the origin of the paramagnetic effect is ultimately associated with nucleation and inhomogeneous spatial redistribution of magnetic vortices in a sample which is cooled down in a magnetic field. It is also shown that the distribution of vortices is extremely sensitive to the interplay of film properties and the real experimental conditions of the measurements.

  18. Paramagnetic moments in YBa2Cu3O7-δ nanocomposite films

    NASA Astrophysics Data System (ADS)

    Dias, F. T.; Vieira, V. N.; Silva, D. L.; Albino Aguiar, J.; Valadão, D. R. B.; Obradors, X.; Puig, T.; Wolff-Fabris, F.; Kampert, E.

    2014-08-01

    We report on magnetization studies in YBa2Cu3O7-δ thin films with dispersed Ba2YTaO6 nanoparticles. The magnetization measurements were made using a superconducting quantum interference device (SQUID) and a vibrating sample magnetometer (VSM). Magnetic moments were measured as functions temperature using zero-field cooling (ZFC) and field-cooled (FC) prescriptions for magnetic fields up to 10 T applied parallel and perpendicular to the ab planes. A paramagnetic response related to the superconducting state was observed during the FC experiments. This effect, known as paramagnetic Meissner effect (PME), apparently increases when the magnetic field is increased. We discuss our PME results in terms of the strong pinning scenario modulated by Ba2YTaO6 nanoparticles dispersed into the superconducting matrix.

  19. Persistent photoconductivity in oxygen deficient YBa2Cu3O7-δ/La2/3Ca1/3MnO3-x superlattices grown by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Kawashima, Kazuhiro; Soltan, Soltan; Logvenov, Gennady; Habermeier, Hanns-Ulrich

    2013-09-01

    We report a large persistent photoconductivity (PPC) in oxygen-reduced YBa2Cu3O7-δ/La2/3Ca1/3MnO3-x (YBCO/LCMO) superlattices (SLs) grown by pulsed laser deposition that scales with oxygen deficiency and is similar to that observed in single layer YBa2Cu3O7-δ films. These results contradict the previous observations, where in sputtered bilayer samples only a transient photoconductivity was found. We argue that the PPC effect in superlattices is caused by the PPC effect due to YBa2Cu3O7-δ layers with limited charge transfer to La2/3Ca1/3MnO3-x. The discrepancy arises from the different permeability of charges across the interface and sheds light on the sensitivity of oxide interface properties to details of their preparation.

  20. Rapid processing method for solution deposited YBa 2Cu 3O 7- δ thin films

    NASA Astrophysics Data System (ADS)

    Dawley, J. T.; Clem, P. G.; Boyle, T. J.; Ottley, L. M.; Overmyer, D. L.; Siegal, M. P.

    2004-02-01

    YBa 2Cu 3O 7- δ (YBCO) films, deposited on buffered metal substrates, are the primary candidate for second-generation superconducting (SC) wires, with applications including expanded power grid transmission capability, compact motors, and enhanced sensitivity magnetic resonance imaging. Feasibility of manufacturing such superconducting wires is dependent on high processing speed, often a limitation of vapor and solution-based YBCO deposition processes. In this work, YBCO films were fabricated via a new diethanolamine-modified trifluoroacetic film solution deposition method. Modifying the copper chemistry of the YBCO precursor solution with diethanolamine enables a hundredfold decrease in the organic pyrolysis time required for MA/cm 2 current density ( Jc) YBCO films, from multiple hours to ∼20 s in atmospheric pressure air. High quality, ∼0.2 μm thick YBCO films with Jc (77 K) values ⩾2 MA/cm 2 at 77 K are routinely crystallized from these rapidly pyrolyzed films deposited on LaAlO 3. This process has also enabled Jc (77 K)=1.1 MA/cm 2 YBCO films via 90 m/h dip-coating on Oak Ridge National Laboratory RABiTS™ textured metal tape substrates. This new YBCO solution deposition method suggests a route toward inexpensive and commercializable ∼$10/kA m solution deposited YBCO coated conductor wires.

  1. [{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.

  2. Influence of gamma irradiation on conductivity of YBa2Cu3O7

    NASA Astrophysics Data System (ADS)

    Manjunatha, H. C.

    2015-08-01

    We report a study on influence of gamma irradiation on conductivity of YBa2Cu3O7. We have measured the mass attenuation coefficient, effective atomic number, electron density and electrical conductivity for various gamma sources of energy ranging from 0.084 MeV to 1.330 MeV (170Tm, 57Co, 141Ce, 203Hg, 51Cr, 113Sn, 22Na, 137Cs, 60Co, 22Na and 60Co). The measured values agree with the theoretical values. The values of these parameters have been found to change with energy and interaction of gamma. We find evidence for a variation of the electrical conductivity of YBa2Cu3O7 with the irradiated photon energy and this variation is shown in figures up to 105 MeV. The variations of effective atomic number and electron density with energy are shown graphically for all photon interactions. Conductivity found to vary with the energy of the irradiated gamma radiation and interaction process of gamma. This kind of studies is important in the field of superconductivity.

  3. 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).

  4. Polarization Domain Switching of Improper Hybrid Ferroelectric (Ca,Sr)3Ti2O7 Crystals

    NASA Astrophysics Data System (ADS)

    Lim, Seong Joon; Gao, Bin; Kim, Jaewook; Huang, Fei-Ting; Cheong, Sang-Wook; RCEM Team

    The observation of switchable polarization loops at room temperature in (Ca,Sr)3Ti2O7, induced by improper hybrid ferroelectricity, has drawn much attention. Since the ferroelectric polarization directly couples with structural distortions (oxygen octahedral tilting and rotation) in hybrid improper ferroelectrics, the energy barrier for polarization switching is predicted to be large, and the observation of ferroelectric polarization loops was a surprise. Furthermore, the observed complexity of the domain wall configuration in (Ca,Sr)3Ti2O7 may complicate the domain wall motion or the domain nucleation for polarization switching. Thus, it is imperative to understand the mechanism and dynamics of polarization domain switching. Particularly, it has to be clarified if polarization switching occurs through 90° or 180° switching. Comparing piezoresponse force microscope and polarized optical microscope images before and after applying electric fields consecutively, we explored the mechanism and dynamics of polarization domain switching. This work is funded by the Gordon and Betty Moore Foundation's EPiQS Initiative through Grant GBMF4413 to the Rutgers Center for Emergent Materials.

  5. Structural chemistry of Au(III)-substituted Ba2YCu3O(7-delta)

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    A series of gold-substituted perovskite superconductors Ba2Y(Cu/1-x/Aux)3O(7-delta)(x = 0-0.1) was 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 was found to be trivalent by X-ray photoelectron spectroscopy. 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, while remaining Cu in the chains is reduced to Cu(I), resulting in an oxygen stoichiometry of less than 7. Finally, no large effect on Tc is observed (Tc = 89 K for x = 0.10), in contrast to the effect of a number of other metal ion dopants. These results are discussed relative to the chemistry of Au(III) and to the use of the metal in structures containing gold and ceramic superconductors.

  6. REVIEW OF PLANT UPTAKE OF 2,3,7,8-TCDD FROM SOIL AND POTENTIAL INFLUENCES OF BIOAVAILABILITY

    EPA Science Inventory

    Volatilization of 2,3,7,8-TCDD from soil and resorption on foliage represents a significant route of contamination. ome studies indicate low-level uptake, translocation from roots to foliage and transpiration from foliage, while one shows more than 95% of 2,3,7,8-TCDD associated ...

  7. BIOAVAILABILITY OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN FROM MUNICIPAL INCINERATOR FLY ASH TO FRESHWATER FISH

    EPA Science Inventory

    The bioavailability of 2,3,7,8-TCDD from municipal incinerator fly ash to freshwater fish was determined. It was observed that carp exposed to fly ash containing all 22 TCDD isomers, or the solvent extract of the fly ash, retain only 2,3,7,8-TCDD. Exposures with fly ash appears t...

  8. Tank 241-AP-107, grab samples 7AP-97-1, 7AP-97-2 and 7AP-97-3 analytical results for the final report

    SciTech Connect

    Steen, F.H.

    1997-12-22

    This document is the final report for tank 241-AP-107 grab samples. Three grab samples were collected from riser 1 on September 11, 1997. Analyses were performed on samples 7AP-97-1, 7AP-97-2 and 7AP-97-3 in accordance with the Compatibility Grab Sampling and Analysis Plan (TSAP) (Sasaki, 1997) and the Data Quality Objectives for Tank Farms Waste Compatibility Program (DQO) (Rev. 1: Fowler, 1995; Rev. 2: Mulkey and Nuier, 1997). The analytical results are presented in the data summary report (Table 1). A notification was made to East Tank Farms Operations concerning low hydroxide in the tank and a hydroxide (caustic) demand analysis was requested. The request for sample analysis (RSA) (Attachment 2) received for AP-107 indicated that the samples were polychlorinated biphenyl (PCB) suspects. Therefore, prior to performing the requested analyses, aliquots were made to perform PCB analysis in accordance with the 222-S Laboratory administrative procedure, LAP-101-100. The results of this analysis indicated that no PCBs were present at 50 ppm and analysis proceeded as non-PCB samples. The results and raw data for the PCB analysis will be included in a revision to this document. The sample breakdown diagrams (Attachment 1) are provided as a cross-reference for relating the tank farm customer identification numbers with the 222-S Laboratory sample numbers and the portion of sample analyzed.

  9. 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...

  10. Tuning the Upconversion Luminescence Lifetimes of KYb2 F7 :Ho(3+) Nanocrystals for Optical Multiplexing.

    PubMed

    Ding, Mingye; Chen, Daqin; Ma, Danyang; Liu, Peng; Song, Kaixin; Lu, Hongwei; Ji, Zhenguo

    2015-12-21

    Conventional luminescent color coding is limited by spectral overlap and the interference of background fluorescence, thus restricting the number of distinguishable identities that can be used in practice. Here, we demonstrate the possibility of generating diverse time-domain codes, specially designed for a single emission band, using lanthanide-doped upconversion nanocrystals. Based on the knowledge of concentration quenching, the upconversion luminescence kinetics of KYb2 F7 : Ho(3+) nanocrystals can be precisely controlled by modifying the dopant concentration of Ho(3+) ions, resulting in a tunable emission lifetime from 75.8 to 1944.5 μs, which suggests the practicality of these time-domain codes for optical multiplexing. PMID:26436998

  11. Coplanar waveguide microwave filter of YBa2Cu3O7

    NASA Technical Reports Server (NTRS)

    Chew, Wilbert; Riley, A. L.; Rascoe, Daniel L.; Hunt, Brian D.; Foote, Marc C.; Cooley, Thomas W.; Bajuk, Louis J.

    1991-01-01

    Thin film low-pass microwave filters have been made with laser-ablated YBa2Cu3O(7-delta) (YBCO) deposited on LaAlO3 substrates, using a coplanar waveguide structure. The coplanar waveguide sections had dimensions suited for integrated circuits. Measured losses in liquid nitrogen were superior to the loss in a similar thin-film copper filter throughout the 0 to 9.5 GHz pass-band. A simple transmission-line model is adequate for filter design using YBCO films with repeatable characteristics. The measured filters demonstrate the performance of fully patterned YBCO after sealing in space-qualifiable hermetic packages. Five packaged filters of this design were delivered to the Naval Research Laboratory as candidates for space flight in the High Temperature Superconductivity Space Experiment.

  12. Coplanar waveguide microwave filter of YBa2Cu3O7

    NASA Astrophysics Data System (ADS)

    Chew, Wilbert; Riley, A. L.; Rascoe, Daniel L.; Hunt, Brian D.; Foote, Marc C.; Cooley, Thomas W.; Bajuk, Louis J.

    1991-07-01

    Thin film low-pass microwave filters have been made with laser-ablated YBa2Cu3O(7-delta) (YBCO) deposited on LaAlO3 substrates, using a coplanar waveguide structure. The coplanar waveguide sections had dimensions suited for integrated circuits. Measured losses in liquid nitrogen were superior to the loss in a similar thin-film copper filter throughout the 0 to 9.5 GHz pass-band. A simple transmission-line model is adequate for filter design using YBCO films with repeatable characteristics. The measured filters demonstrate the performance of fully patterned YBCO after sealing in space-qualifiable hermetic packages. Five packaged filters of this design were delivered to the Naval Research Laboratory as candidates for space flight in the High Temperature Superconductivity Space Experiment.

  13. 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.

  14. Focal Cortical Lesion Detection in Multiple Sclerosis: 3T DIR versus 7T FLASH-T2*

    PubMed Central

    Nielsen, A. Scott; Kinkel, R. Philip; Tinelli, Emanuele; Benner, Thomas; Cohen-Adad, Julien; Mainero, Caterina

    2014-01-01

    Purpose To evaluate the inter-rater agreement of cortical lesion detection using 7T FLASH-T2* and 3T DIR sequences. Materials and Methods Twenty-six patients with multiple sclerosis were scanned on a human 7T (Sidemen’s) and 3T MRI (TIM Trio, Sidemen’s) to acquire 3T DIR/MEMPR and 7T FLASH-T2* sequences. Four independent reviewers scored and categorized cortical lesions in the bilateral pre-central gyri (motor strips) as leukocortical, intracortical, or subpial. Inter-rater agreement was assessed according to lesion category using the kappa statistic. The sensitivity of recent MAGNIMS consensus guidelines for cortical lesion detection using 3T DIR was assessed with 7T FLASH-T2* as the reference gold standard. Results Inter-rater agreement at 7T was excellent compared to 3T (k=0.97 vs. 0.12). FLASH-T2* at 7T detected subpial lesions while 3T DIR did not. The predicted sensitivity of 3T DIR sequence for cortical lesions in vivo is modest (range of 13.6 to 18.3%). Conclusion 7T FLASH-T2* detects more cortical—particularly subpial—lesions compared to 3T DIR. In the absence of DIR/post-mortem data, 7T FLASH-T2* is a suitable gold-standard instrument and should be incorporated into future consensus guidelines. PMID:22045554

  15. Liquid Phase Growth of YBa2Cu3O7-x at Low Temperatures Using KOHFLUX

    NASA Astrophysics Data System (ADS)

    Yamada, Yasuji; Funaki, Shuhei; Nakayama, Fumiya; Okunishi, Ryota; Miyachi, Yugo

    Molten KOH method, which was reported for the growth of YBa2Cu4O8 (Y124) crystal, was applied to synthesize and grow YBa2Cu3O7-x (Y123) crystal. Y123 phase was synthesized by controlling growth temperature and oxygen partial pressure. The shape of synthesized grains was cubic-like, indicating that they grew by the transportation of solute through liquid phase. Using KOH flux method, substitution of rare-earth elements for Y in Y123 phase was easily obtained. Liquid phase epitaxy of Y123 film on a single crystalline substrate was achieved by slow cooling flux method but not by top-seeded solution growth yet.

  16. 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.

  17. Induction of Heat Shock Proteins and Antioxidant Enzymes in 2,3,7,8-TCDD-Induced Hepatotoxicity in Rats

    PubMed Central

    Kim, Hyun-Sook; Park, So-Young; Yoo, Ki-Yeol

    2012-01-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) is an environmental toxicant with a polyhalogenated aromatic hydrocarbon structure and is one of the most toxic man-made chemicals. Exposure to 2,3,7,8-TCDD induces reproductive toxicity, immunotoxicity, and hepatotoxicity. In this study, we evaluated how 2,3,7,8-TCDD-induced hepatotoxicity affect the expression of heat shock proteins and antioxidant enzymes using the real-time polymerase chain reaction (PCR) in rat. 2,3,7,8-TCDD increased heat shock protein (Hsp27, α-B-crystallin, Mortalin, Hsp105, and Hsp90s) and antioxidant enzymes (SOD-3, GST and catalase) expression after a 1 day exposure in livers of rats, whereas heat shock protein (α-B-crystallin, Hsp90, and GRP78) and antioxidant enzymes (SOD-1, SOD-3, catalase, GST, and GPXs) expression decreased on day 2 and then slowly recovered back to control levels on day 8. These results suggest that heat shock proteins and antioxidant enzymes were induced as protective mechanisms against 2,3,7,8-TCDD induced hepatotoxicity, and that prolonged exposure depressed their levels, which recovered to control levels due to reduced 2,3,7,8-TCDD induced hepatotoxicity. PMID:23269910

  18. Interfacial effects revealed by ultrafast relaxation dynamics in BiFeO3/YBa2Cu3O7 bilayers

    NASA Astrophysics Data System (ADS)

    Springer, D.; Nair, Saritha K.; He, Mi; Lu, C. L.; Cheong, S. A.; Wu, T.; Panagopoulos, C.; Chia, Elbert E. M.; Zhu, Jian-Xin

    2016-02-01

    The temperature dependence of the relaxation dynamics in the bilayer thin film heterostructure composed of multiferroic BiFeO3 (BFO) and superconducting YBa2Cu3O7 (YBCO) grown on a (001) SrTiO3 substrate is studied by a time-resolved pump-probe technique, and compared with that of pure YBCO thin film grown under the same growth conditions. The superconductivity of YBCO is found to be retained in the heterostructure. We observe a speeding up of the YBCO recombination dynamics in the superconducting state of the heterostructure, and attribute it to the presence of weak ferromagnetism at the BFO/YBCO interface as observed in magnetization data. An extension of the Rothwarf-Taylor model is used to fit the ultrafast dynamics of BFO/YBCO, that models an increased quasiparticle occupation of the ferromagnetic interfacial layer in the superconducting state of YBCO.

  19. High Electrical Conductivity in Ni3(2,3,6,7,10,11-hexaiminotriphenylene)2, a Semiconducting Metal-Organic Graphene Analogue

    SciTech Connect

    Sheberla, Dennis; Sun, Lei; Blood-Forsythe, Martin A.; Er, Süleyman; Wade, Casey R.; Brozek, Carl K.; Aspuru-Guzik, Alán; Dinc,; #259; Mircea,

    2014-09-22

    Reaction of 2,3,6,7,10,11-hexaaminotriphenylene with Ni2+ in aqueous NH3 solution under aerobic conditions produces Ni3(HITP)2 (HITP = 2,3,6,7,10,11-hexaiminotriphenylene), a new two-dimensional metal–organic framework (MOF). The new material can be isolated as a highly conductive black powder or dark blue-violet films. Two-probe and van der Pauw electrical measurements reveal bulk (pellet) and surface (film) conductivity values of 2 and 40 S·cm–1, respectively, both records for MOFs and among the best for any coordination polymer.

  20. The onset of ferromagnetism and superconductivity in [La0.7Sr0.3MnO3(n u.c.)/YBa2Cu3O7(2 u.c.)]20 superlattices.

    PubMed

    Dybko, K; Aleshkevych, P; Sawicki, M; Paszkowicz, W; Przyslupski, P

    2013-09-18

    With the aim of studying the interface magnetism, the onset of ferromagnetism and the onset of the transition to the superconducting state a series of [La0.7Sr0.3MnO3(n u.c.)/YBa2Cu3O7(2 u.c.)]20 (LSMO/YBCO) superlattices with nominally varying layer thickness of the LSMO from one to four unit cells (u.c.) was prepared and characterized by x-ray diffraction, electronic transport, magnetization and ferromagnetic resonance measurements. Spontaneous magnetization was observed for a superlattice with four u.c. LSMO layer thickness in a multilayer structure. Superlattices with 3 u.c. of LSMO and lower layer thicknesses did not show a signature of ferromagnetism. The onset of superconductivity was observed for superlattices with one and two LSMO layer u.c. thickness. PMID:23962975

  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, 2010 CFR

    2010-07-01

    ...- amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3- -, trisodium salt (generic). 721.5262 Section 721.5262...,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-......

  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

    ...- amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3- -, trisodium salt (generic). 721.5262 Section 721.5262...,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-......

  3. Functional characterization of SAG/RBX2/ROC2/RNF7, an antioxidant protein and an E3 ubiquitin ligase

    PubMed Central

    Li, Hua

    2013-01-01

    SAG (Sensitive to Apoptosis Gene), also known as RBX2 (RING box protein 2), ROC2 (Regulator of Cullins 2), or RNF7 (RING Finger Protein 7), was originally cloned in our laboratory as a redox inducible antioxidant protein and later characterized as the second member of the RBX/ROC RING component of the SCF (SKP1-CUL-F-box Proteins) E3 ubiquitin ligase. When acting alone, SAG scavenges oxygen radicals by forming inter- and intra- molecular disulfide bonds, whereas by forming a complex with other components of the SCF E3 ligase, SAG promotes ubiquitination and degradation of a number of protein substrates, including c-JUN, DEPTOR, HIF-1α, IκBα, NF1, NOXA, p27, and procaspase-3, thus regulating various signaling pathways and biological processes. Specifically, SAG protects cells from apoptosis, confers radioresistance, and plays an essential and non-redundant role in mouse embryogenesis and vasculogenesis. Furthermore, stress-inducible SAG is overexpressed in a number of human cancers and SAG overexpression correlates with poor patient prognosis. Finally, SAG transgenic expression in epidermis causes an early stage inhibition, but later stage promotion, of skin tumorigenesis triggered by DMBA/TPA. Given its major role in promoting targeted degradation of tumor suppressive proteins, leading to apoptosis suppression and accelerated tumorigenesis, SAG E3 ligase appears to be an attractive anticancer target. PMID:23136067

  4. Upconversion luminescence properties and color tunability of 12CaOṡ7Al2O3:Ho3+/Yb3+ single crystal

    NASA Astrophysics Data System (ADS)

    Qu, Yunfei; Qiu, Zhaozhong; Wang, Rui; Liu, Liang; Tao, Ye; Zhou, Jianjun

    2016-03-01

    Rear earth (RE) ions-doped 12CaOṡ7Al2O3 single crystal has been successfully prepared by Czochralski method. Under 980 nm excitation, a strong green upconversion emission at 548 nm and a weaker red upconversion emission at 662 nm were observed. The green upconversion emission is corresponding to the transition of 5F 4/5S2 →5I8 of Ho3+, and the red one is corresponding to the transition of 5F5 →5I8 of Ho3+. A much weaker NIR band at 762 nm is also observed, which corresponds to the 5F 4/5S2 →5I7 transition of Ho3+. The pump dependence and luminescence decay dynamics spectra show the green and red upconversion are populated by two-photon process, and the upconversion mechanisms are analyzed in detail. The color of the upconversion luminescence can be changed by simply adjusting the excitation power. RE ions-doped 12CaOṡ7Al2O3 single crystal with these properties is expected to have broad application prospects in solid-state multicolor display and instrument integration. RE ions-doped 12CaOṡ7Al2O3 single crystal has the ability to replace some traditional single crystals such as LiNbO3 in many applications.

  5. Epitaxial CeO2 buffer layers for YBa2Cu3O(7-delta) films on sapphire

    NASA Astrophysics Data System (ADS)

    Maul, M.; Schulte, B.; Haeussler, P.; Frank, G.; Steinborn, T.; Fuess, H.; Adrian, H.

    1993-08-01

    The paper reports the successful in situ preparation of thin epitaxial CeO2 buffer layers and YBa2Cu3O(7-delta) (YBCO) films on (1 -1 0 2) Al2O3 substrates by electron beam coevaporation, using an evaporation system (Leybold L560) with four sources. Electron beam sources were used for Y, Ba, and Ce, while Cu was evaporated from a resistively heated tungsten boat. The buffer layers show very smooth surfaces and structural properties close to those of a single crystal. High quality YBCO films grown on these buffer layers have Tc not 88 K or above and j(c) values of 10 exp 6 A/sq cm or greater.

  6. Volumetric Measurement of Labile Ions Through Corrosion of YBa2Cu3O7-x

    NASA Astrophysics Data System (ADS)

    Dou, S. X.; Liu, H. K.; Bourdillon, A. J.; Tan, N. X.; Zhou, J. P.; Sorrell, C. C.; Easterling, K. E.

    The stability of sintered YBa2Cu3O7-x {123} in various aqueous solutions was investigated. It was found that all aqueous solutions have detrimental effects on superconduction in {123}. Based on the evolution of O2 through the reaction of {123} with acid, the volumetric measurement technique has been established for determining the quantity of Cu3+ in {123} with excellent reproducibility. In nitric acid the sintered {123} is much more stable than Ag, Cu or Ni metals, which are sometimes used in processing {123}, for example as cladding in wire drawing. {123} tends to passivate in concentrated acid. Impurity-doped and multiphase specimens generally suffer enhanced corrosion in water due to the formation of micro-electrochemical cells. Material with the tetragonal crystal structure is more stable in water than that with the orthorhombic structure, indicating that the sensitivity of {123} to water can be attributed to the presence of Cu3+ which is the driving force for rapid oxidation and reduction reactions in water.

  7. Anisotropic optical properties of YBa sub 2 Cu sub 3 O sub 7

    SciTech Connect

    Nee, T. )

    1992-06-15

    Based upon the published results of YBa{sub 2}Cu{sub 3}O{sub 7} single-crystal reflectance spectra measured at room temperature, the empirical anisotropic spectral density functions and quasidielectric functions {epsilon}{sub 1{ital j}}+{ital i}{epsilon}{sub 2{ital j}} ({ital j}={ital a},{ital b},{ital c}) are determined in the 0.05 to 6 eV spectral range. These functions are an excellent fit to the reflectance spectra of samples in single-crystal, twin-crystal, and polycrystalline forms; they agree well with the published anisotropic transport and ellipsometry data. For polarizations along the {ital a} and {ital b} axes, the numerically determined empirical spectral density functions have shown two interband absorption peaks at 2.5 and 5 eV. For energy above 3 eV, the spectral density functions do not agree with the published theoretical interband conductivities that are derived from the band structure calculations.

  8. 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. PMID:27029789

  9. 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.

  10. 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

  11. 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, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Chromate(2-), -7-nitro-1-substituted... Significant New Uses for Specific Chemical Substances § 721.5288 Chromate(2-), -7-nitro-1-substituted] -1... chemical substance identified generically as chromate(2-), -7- nitro-1-substituted] -1-substituted]-,...

  12. 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, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Chromate(2-), -7-nitro-1-substituted... Significant New Uses for Specific Chemical Substances § 721.5288 Chromate(2-), -7-nitro-1-substituted] -1... chemical substance identified generically as chromate(2-), -7- nitro-1-substituted] -1-substituted]-,...

  13. 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, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Chromate(2-), -7-nitro-1-substituted... Significant New Uses for Specific Chemical Substances § 721.5288 Chromate(2-), -7-nitro-1-substituted] -1... chemical substance identified generically as chromate(2-), -7- nitro-1-substituted] -1-substituted]-,...

  14. 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

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Chromate(2-), -7-nitro-1-substituted... Significant New Uses for Specific Chemical Substances § 721.5288 Chromate(2-), -7-nitro-1-substituted] -1... chemical substance identified generically as chromate(2-), -7- nitro-1-substituted] -1-substituted]-,...

  15. 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, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Chromate(2-), -7-nitro-1-substituted... Significant New Uses for Specific Chemical Substances § 721.5288 Chromate(2-), -7-nitro-1-substituted] -1... chemical substance identified generically as chromate(2-), -7- nitro-1-substituted] -1-substituted]-,...

  16. A proposed occupational exposure limit for 2,3,7,8-tetrachlorodibenzo-p-dioxin.

    PubMed

    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.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2972183

  17. Metamagnetism and Nonlinear Susceptibilities in the Bilayer Ruthenate Sr3Ru2O7

    NASA Astrophysics Data System (ADS)

    Phelan, D.; Shivaram, B.; Vecchione, A.; Fittipaldi, Rosalba

    We report measurements of the third and fifth order nonlinear susceptibilities in the correlated oxide metamagnet, Sr3Ru2O7 for both orientations of the magnetic field, H parallel to the c-axis and in the basal plane. In both geometries we observe peaks in the temperature dependence of the higher order susceptibilities. The position in temperature where the peak in the fifth order susceptibility occurs is at half the temperature where a peak in the third order susceptibility is seen. The latter in turn is at half the temperature where the peak in the linear susceptibility is known to occur. This simple scaling is common to both orientations of the magnetic field. These results will be discussed in the context of similar work with heavy fermion metamagnets1. ``Universality in the Magnetic Response of Metamagnetic Metals'', B.S. Shivaram, D.G. Hinks, and Pradeep Kumar, Phys. Rev. B 89 , 241107(R), 2014.

  18. Observation of Pr magnetic order in PrBa2Cu3O7

    NASA Astrophysics Data System (ADS)

    Skanthakumar, S.; Lynn, J. W.; Rosov, N.; Cao, G.; Crow, J. E.

    1997-02-01

    Neutron-diffraction experiments have been carried out to investigate the magnetic order in PrBa2Cu3O7. Our neutron data indicate that the Cu spins order above 300 K. This ordering is not significantly affected at low temperatures, where new magnetic Bragg peaks develop below 17 K that must be associated with the antiferromagnetic ordering of Pr spins, with an ordered moment of 0.79(5)μB. This rules out the possibility recently proposed by Nehrke and Pieper [Phys. Rev. Lett. 76, 1936 (1996)] that the new magnetic Bragg peaks arise from a spin reorientation of the Cu spins and that the Pr carries essentially no moment.

  19. Mechanical response of the flux lines in ceramic YBa2Cu3O7

    NASA Astrophysics Data System (ADS)

    Luzuriaga, J.; André, M.-O.; Benoit, W.

    1992-06-01

    We have studied the mechanical response of the flux-line lattice (FLL) in ceramic samples of YBa2Cu3O7 by means of a low-frequency forced pendulum. The internal friction and elastic modulus variation of the FLL have been measured as a function of temperature for different values of the applied stress. A somewhat different behavior was observed whether a zero-field-cooling or field-cooling procedure was followed. Measurements of the internal friction and elastic modulus as a function of the applied stress at constant temperature show amplitude-dependent dissipation, with a maximum dissipation at intermediate values of the stress. This dependence is well fitted by a rheological model of extended dry friction, if we restrict ourselves to the dissipation and modulus at fixed temperature. The agreement is not so good when attempting to extend the model to fit the temperature dependence.

  20. 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. PMID:15185717

  1. Laser writing and rewriting on YBa2Cu3O7 films

    NASA Astrophysics Data System (ADS)

    Shen, Y. Q.; Freltoft, T.; Vase, P.

    1991-09-01

    High-resolution patterning (4 microns) has been achieved on epitaxial thin films of the high-temperature superconductor YBa2Cu3O(7-delta) using laser writing. A focused laser beam is applied to write semiconducting patterns on superconducting films in a vacuum or in a nitrogen atmosphere. The semiconducting patterns are shown to be formed by a reduction of the oxygen content due to local heating caused by the laser beam. The process does not cause any structural damage and does not change the surface morphology. When reapplying the same laser beam and rewriting the film in an oxygen atmosphere, it is possible to restore the superconductive properties. The application of this method for production of superconducting microelectronic circuits is discussed.

  2. Quasiparticle Scattering Rate and Antiferromagnetic Excitations in YBa_2Cu_3O_7.

    NASA Astrophysics Data System (ADS)

    Stojković, Branko P.; Blumberg, G.; Klein, M. V.

    1996-03-01

    In quasi-two-dimensional d-wave superconductors Van Hove singularities close to the Fermi surface lead to magnetic quasi-particle excitations.(G. Blumberg, B. P. Stojković and M. V. Klein, preprint.) Assuming a model electron-magnon interaction and realistic electronic band structure for YBa_2Cu_3O_7, we calculate the inelastic electronic scattering rate in both normal and superconducting states. In agreement with the momentum dependent spectral function broadening observed in YBCO in the superconducting state by photoemission spectroscopy, we find different quasiparticle scattering rates as a function of energy and temperature for different regions of the Brillouin zone. We calculate the magnetic excitation spectra in momentum space and use them to discuss the implications of our results for NMR, inelastic neutron scattering, and Raman spectroscopy.

  3. Nature of Y1Ba2Cu3O7 nucleation centers on ceria buffers

    NASA Astrophysics Data System (ADS)

    Solovyov, Vyacheslav F.; Develos-Bagarinao, Katherine; Li, Qiang; Qing, Jie; Zhou, Juan

    2010-01-01

    The purpose of this study is to enhance properties of the second-generation wires by increasing the density of Y1Ba2Cu3O7 (YBCO) nucleation centers on the surface of the ceria buffer. To identify the nature of the nucleation centers, we compare nucleation kinetics and performance of YBCO layers deposited by the metal-organic process on a standard RABiTS tape to YBCO on ceria buffers with well-controlled structure and surface morphology. The structure of the YBCO layer at the early stage of nucleation and growth is determined by high-flux synchrotron x-ray diffraction. It is shown that the best buffers exhibit high YBCO nucleation rates and produce YBCO nuclei with the least cation disorder. The high YBCO nucleation rate is associated with a high density of threading dislocation outcrops. A strategy for buffer optimization is identified.

  4. Revisiting the vortex-core tunnelling spectroscopy in YBa2Cu3O7

    NASA Astrophysics Data System (ADS)

    Bruér, Jens; Maggio-Aprile, Ivan; Jenkins, Nathan; Ristić, Zoran; Erb, Andreas; Berthod, Christophe; Fischer, Øystein; Renner, Christoph

    2016-03-01

    The observation by scanning tunnelling spectroscopy of Abrikosov vortex cores in the high-temperature superconductor YBa2Cu3O7-δ (Y123) has revealed a robust pair of electron-hole symmetric states at finite subgap energy. Their interpretation remains an open question because theory predicts a different signature in the vortex cores, characterized by a strong zero-bias conductance peak. Here, we present scanning tunnelling spectroscopy data on very homogeneous Y123 at 0.4 K revealing that the subgap features do not belong to vortices: they are actually observed everywhere along the surface with high spatial and energy reproducibility, even in the absence of magnetic field. Detailed analysis and modelling show that these states remain unpaired in the superconducting phase and belong to an incoherent channel, which contributes to the tunnelling signal in parallel with the superconducting density of states.

  5. 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.

  6. 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.

  7. 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.

  8. Pilot study on health effects of environmental 2,3,7,8-TCDD in Missouri

    SciTech Connect

    Webb, K.; Evans, R.G.; Stehr, P.; Ayres, S.M.

    1987-01-01

    Waste oil contaminated with 2,3,7,8-TCDD was sprayed at various sites in the state of Missouri. Eighty-two individuals who reported living or working in TCDD-contaminated areas and 40 individuals with little or no exposure to TCDD were selected for study; 85% elected to participate in the study. Data were obtained from medical histories, general physicals, neurological and dermatological examinations, and laboratory tests. There were no cases of chloracne reported. The only hematologic comparison that was significant was a higher mean platelet count in the exposed group. This study did not produce any firm indication of increased disease prevalence related to environmental TCDD exposures. Since this was a pilot study, it is important that we continue to limit human exposure to dioxin to the lowest levels technologically feasible until definitive answers to the health consequences of exposure are determined.

  9. Design, Synthesis, and Potential Antidepressant-like Activity of 7-prenyloxy-2,3-dihydroflavanone Derivatives.

    PubMed

    Zhen, Xing-Hua; Quan, Ying-Chun; Peng, Zhou; Han, Yan; Zheng, Zhou-Jun; Guan, Li-Ping

    2016-06-01

    A series of 7-prenyloxy-2, 3-dihydroflavanone derivatives were synthesized and screened for their antidepressant-like activity. Among them, it was observed that compounds 5j and 5k were found to be the most antidepressant-like activity. In addition, it was found that compounds 5j and 5k significantly increased the concentrations of the main neurotransmitters 5-HT and NE in the hippocampus, hypothalamus, and cortex. Compounds 5j and 5k also significantly increased the contents of 5-HIAA in the hippocampus and cortex, shut down 5-HT metabolism compared with mice treated with stress vehicle. These results suggested that compounds 5j and 5k displayed potent antidepressant-like properties that were mediated via neurochemical systems. PMID:26705885

  10. Non-volatile resistive switching in the dielectric superconductor YBa(2)Cu(3)O(7-δ).

    PubMed

    Acha, C; Rozenberg, M J

    2009-01-28

    We report on the reversible, non-volatile and polarity-dependent resistive switching between superconductor and insulator states at the interfaces of an Au/YBa(2)Cu(3)O(7-δ) (YBCO)/Au system. We show that, upon application of electric pulses, the superconducting state of YBCO in regions near the electrodes can be reversibly removed and restored. In addition, four-wire measurements reveal that pulsing also induces significant non-volatile changes in the bulk resistance. We argue that our observations are compatible with a scenario where the switching effect is due to migration of oxygen ions along grain boundaries that control the inter-grain superconducting coupling. PMID:21715820

  11. 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

  12. Growth behavior of YBa sub 2 Cu sub 3 O sub 7 minus. delta. and NdBa sub 2 Cu sub 3 O sub 7 minus. delta. thin films observed by electron diffraction

    SciTech Connect

    Shimizu, T.; Nonaka, H.; Arai, K. )

    1991-07-29

    Growth behavior of thin films of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} and NdBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} has been observed in reflection high-energy electron diffraction (RHEED) during coevaporation of constituent metal atoms with a NO{sub 2} supersonic molecular beam. The intensity oscillations of RHEED specular beam have been observed during deposition. The nucleation behavior of NdBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} is found to be different from that of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} in RHEED observation.

  13. 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

  14. Two isotypic diphosphates Li M2H 3(P 2O 7) 2 ( M=Ni, Co) containing ferromagnetic zigzag MO 6 chains

    NASA Astrophysics Data System (ADS)

    Yang, Tao; Yang, Sihai; Liao, Fuhui; Lin, Jianhua

    2008-06-01

    Two new isotypic phosphates LiNi 2H 3(P 2O 7) 2 ( 1) and LiCo 2H 3(P 2O 7) 2 ( 2) have been hydrothermally synthesized and structurally characterized by the single-crystal X-ray diffraction technique. They crystallize in the monoclinic space group C2/ c with the lattice: a=10.925(2) Å, b=12.774(3) Å, c=8.8833(18) Å, β=123.20(3)° for 1 and a=10.999(2) Å, b=12.863(3) Å, c=8.9419(18) Å, β=123.00(3)° for 2. The transition metal atoms are octahedrally coordinated, whereas the lithium and phosphorus atoms are all tetrahedrally coordinated. As the lithium-induced derivatives of MH 2P 2O 7 ( M=Ni, Co), 1 and 2 possess the same structure with MH 2P 2O 7 in terms of topology, comprising the MO 6 zigzag chains and P 2O 7 as the interchain groups. The magnetisms of 1 and 2 could be interpreted by adopting a quasi-one-dimensional (1D) zigzag chain model as that in their parent compounds: both 1 and 2 have ferromagnetic (FM) NiO 6/CoO 6 chains; 1 shows a FM cluster glass behavior at low temperatures, which is originated from the possible antiferromagnetic (AFM) next-nearest-neighbour intrachain interactions; 2 shows a AFM ordering at TN=2.6 K and a metamagnetic transition at HC=4.2 kOe at 1.8 K.

  15. 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

  16. Magnetotransport study of Kondo compound Ce(Ni0.7Cu0.3)2Al3

    NASA Astrophysics Data System (ADS)

    Yadam, Sankararao; Singh, Durgesh; Venkateshwarlu, D.; Gangrade, Mohan Kumar; Samatham, S. Shanmukharao; Ganesan, V.

    2015-06-01

    CeNi2Al3 system has evolved in to a known thermoelectric material with a usable figure of merit at low temperatures. Kondo effect plays a crucial role in the enhancement of TEP in this system especially when the Ni site is substituted with non-magnetic elements like Cu. Effect of high magnetic fields on various properties of this system is yet to be explored. Ce(Ni0.7Cu0.3)2Al3 is a representative sample that has a significant enhancement of TEP whose reasons are being explored recently. Here we report the magnetoresistivity measurements on this sample down to 2K and fields upto 14T. The famous negative ln(T) rise with a minimum at 14.5 K is getting suppressed by the magnetic fields. Magnetic correlations are observed with increasing magnetic field strength in the form of a hump like behavior due to competition between Kondo and RKKY interactions. This hump is shifted to higher temperatures with increase in the field strength which indicates probable onset of ferromagnetic correlations that is being corroborated by the observed negative magnetoresistance at low temperatures.

  17. Hepatocellular carcinomas promote tumor-associated macrophage M2-polarization via increased B7-H3 expression.

    PubMed

    Kang, Fu-Biao; Wang, Ling; Li, Dong; Zhang, Yin-Ge; Sun, Dian-Xing

    2015-01-01

    B7 family members are aberrantly expressed on the human hepatocellular carcinoma (HCC) cell surface, and induce local and systemic immunosuppression. Tumor-associated macrophages (TAMs) are a significant immune cell subpopulation in HCC and may be induced to express co-inhibitory molecules including B7 homologue 3 (B7-H3). In the present study, 79.3% of the HCC tissue samples showed high expression of B7-H3 which was positively correlated with the number of TAMs in the evaluated cancer tissues. Furthermore, high levels of TAMs or B7-H3 were associated with a shorter survival time of the HCC patients. In vitro, B7-H3 expression was upregulated at both the mRNA and protein levels in phorbol 12-myristate 13-acetate (PMA)-induced THP-1 cells cocultured with HepG2 cells in a Transwell system. In addition, B7-H3 promoted PMA-induced THP-1 cells to differentiate into the M2 phenotype, with evidence of increases in arginase 1 (Arg1), vascular endothelial cell growth factor (VEGF) and macrophage-derived chemokine (CCL22) mRNA following coculture with HepG2 cells. However, this phenomenon was abrogated through knockdown of B7-H3 by RNA interference or by blocking the signal transducer and activator of trans-cription 3 (STAT3) signaling pathway. Overall, these results suggest that the B7-H3-mediated STAT3 signaling pathway is an important mechanism for inducing M2-type polarization of TAMs, which accelerates HCC development. Our findings may support the development of novel therapeutic strategies for HCC patients through the skewing of the TAM phenotype by targeting the B7-H3 signaling pathway. PMID:25370943

  18. Development of the 3.7 GHz LHCD system on HL-2A

    NASA Astrophysics Data System (ADS)

    Lu, B.; Huang, M.; Zeng, H.; Bai, X. Y.; Mao, X. H.; Lu, Z. H.; Liang, J.; Kang, Z. H.; Wang, M. W.; Feng, K.; Wang, H.; Wang, C.; Wang, J. Q.; Wei, S.; Yao, T.; Bu, Y. N.; Feng, J.; Cheng, G. Y.; Song, S. D.; Xia, D. H.; Rao, J.

    2014-10-01

    A 2 MW-3.7 GHz lower hybrid current drive (LHCD) system is under development for physics experiments on the HL-2A device. The RF Power is generated by four TH2103A klystron amplifiers and propagates in the TE10 mode through WR284 waveguides. The transmission lines with a length of 20 m to 30 m are pressurized with 2 bars of nitrogen to decrease the possibility of arcing. The launcher, based on the passive-active multi-junction (PAM) concept, has been developed and is currently being realized. It was designed for a power spectrum peaked at N|| = 2.75 with good coupling properties over a wide range of plasma parameters. The four klystrons are fed by a high-voltage power supply (HVPS) based on the pulse step modulation (PSM) concept with a fast switch-off time of less than ten μs. This system is expected to be in operation within 1 years and will explore many international thermonuclear experimental reactor (ITER) related LH experiments in the following years.

  19. Positron annihilation in the hydrogenated granular superconductor of YBa 2Cu 3O 7

    NASA Astrophysics Data System (ADS)

    Lam, C. C.; Shao, L. W.; Jin, X.; Chen, W. M.; Xiong, H. Q.; Feng, J.; Qi, S. R.; Hung, K. C.

    1996-02-01

    In this paper, we have used the sputtering neutral-particles mass spectroscopy (SNMS) and positron-annihilation technique to investigate the effect of hydrogenation on the physical properties of different oxygenated YBa 2Cu 3O 7-δ superconductors. Under the same of hydrogenation treatment, the hydrogenation effects on the superconductors are compared to the non-superconductors. It was shown that the hydrogen concentration in the superconductors is about eight times of the non-superconductor's. It was proven that the long lifetime of positrons in the annihilation process is determined by the variation of the concentrations of monovacancies and microvoids, which takes place in both of intragrain and intergrain samples. The hydrogenation effect can be classified into four stages. At the first stage, the hydrogen atoms fill both monovacancy and microvoid. At the end of the first stage, the long lifetime τ2 reaches the maximum value which is determined by the lifetime of the positron in the monovacancy-free and nearly microvoid-exhausted YBCO sample. In the second stage, the hydrogen charging will lead to creation of new monovacancies; this will make the long lifetime τ2 drop monotonically to its minimum value. In the third stage, further hydrogen charging promotes the formation of microvoids, and leads to an increasing τ2 up to a saturation value, which indicates the equilibrium concentrations of monovacancy and microvoid at that temperature.

  20. 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.

  1. 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.

  2. Enhancement of the photoluminescence and long afterglow properties of Sr2MgSi2O7:Eu(2+) phosphor by Dy(3+) co-doping.

    PubMed

    Sahu, Ishwar Prasad; Bisen, D P; Brahme, Nameeta; Ganjir, Manju

    2015-12-01

    Sr2MgSi2O7:Eu(2+) and Sr2MgSi2O7:Eu(2+),Dy(3+) long afterglow phosphors were synthesized under a weak reducing atmosphere by the traditional high temperature solid state reaction method. The synthesized phosphors were characterized by powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and photo-, thermo- and mechanoluminescence spectroscopic techniques. The phase structure of the sintered phosphor was an akermanite type structure, which belongs to tetragonal crystallography. The thermoluminescence properties of these phosphors were investigated and compared. Under ultraviolet light excitation, the emission spectra of both prepared phosphors were composed of a broad emission band peaking at 470 nm. When the Sr2MgSi2O7:Eu(2+) phosphor was co-doped with Dy(3+), the photoluminescence (PL), afterglow and mechanoluminescence (ML) intensity were strongly enhanced. The decay graph indicated that both the sintered phosphors contained fast decay and slow decay processes. The ML intensities of Sr2MgSi2O7:Eu(2+) and Sr2MgSi2O7:Eu(2+),Dy(3+) phosphors were increased proportionally with increasing impact velocity, a finding that suggests that these phosphors could be used as sensors to detect the stress of an object. PMID:25847277

  3. Strategic Research on Performance Optimization of YBa2Cu3O7 Coated Conductors

    SciTech Connect

    Aytug, Tolga; Christen, David K; Kim, Kyunghoon; Lupini, Andrew R; Paranthaman, Mariappan Parans; Polat, Ozgur; Thompson, James R; Xiong, X.; Selvamanickam, V.; Meyer III, Harry M; Qiu, Xiaofeng

    2008-01-01

    Practical applications of second generation (2G) high temperature superconductor (HTS) wires require high critical current density, Jc, at high temperatures and magnetic fields. It has been well established that Jc can be increased via nanostructural engineering of artificial pinning centers within the HTS matrix. In the present work, composite LaMnO3:MgO (LMO:MgO) cap buffer layers with varying MgO contents 5 vol% up to 75 vol% have been grown on homo-epi MgO/IBAD(MgO) substrates to enhance the performance of YBa2Cu3O7-x (YBCO) films. Results showed formation of phase separated MgO nanocolumns within the LMO matrix. The impact of these nanocolumns on the superconducting properties of YBCO films deposited on the nanostructured layer was investigated by electrical transport measurements. Such YBCO films showed better in-field performance compared to that of YBCO films on standard LMO cap films. In particular, measurements of the field-angle dependence revealed c-axis correlated pinning for YBCO films on these composite cap layers. The present results demonstrate a practical approach to obtain high performance superconducting wires.

  4. Peripheral neuropathy after occupational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).

    PubMed

    Sweeney, M H; Fingerhut, M A; Arezzo, J C; Hornung, R W; Connally, L B

    1993-06-01

    Reports of human exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) describe signs and symptoms consistent with exposure-related peripheral neuropathy. In a cross-sectional study, prevalence of peripheral neuropathy was measured in 265 workers exposed 15 years earlier to chemicals contaminated with TCDD and in 244 unexposed, age-, race-, gender- and community-matched comparisons. Cases of peripheral neuropathy were defined from examination, electrophysiologic and quantitative sensory tests, and symptoms. Exposure was assessed by measuring lipid-adjusted serum TCDD levels. The mean serum TCDD level for workers (220 parts per trillion (ppt)) was significantly higher than for referents (7 ppt) (p < .0001). Thirty-two percent of both worker and referent groups met the case definition for peripheral neuropathy. In the logistic regression analyses, serum TCDD level was not related to peripheral neuropathy. These data suggest that despite continued high serum TCDD levels, peripheral neuropathy is not a long-term sequela of high exposure to TCDD-contaminated chemicals. However, the study cannot preclude the occurrence and subsequent resolution of acute effects caused by high exposure, as experienced in Seveso and possibly by some workers, while exposed to high levels of TCDD-contaminated substances. PMID:8392292

  5. Effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on scratching behavior in mice.

    PubMed

    Ono, Rie; Kagawa, Yoto; Takahashi, Yuji; Akagi, Masaki; Kamei, Chiaki

    2010-03-01

    The present study was performed to study the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on scratching behavior in hairless mice, which are highly sensitive to pruritogens (mediators causing itching), except for histamine, and are suitable for time-course studies due to their hairless skin. TCDD is a well-known environmental pollutant that causes skin diseases with itching; therefore, we examined whether TCDD induced itching. Oral administration of TCDD caused no increase in scratching behavior when used alone, whereas TCDD in combination with distilled water or acetone/olive oil application caused a significant increase in scratching behavior. Furthermore, nerve growth factor (NGF) content in the skin increased significantly. A single administration of chlorpheniramine (histamine H1 receptor antagonist), tranilast (chemical mediator release inhibitor) and olopatadine (histamine H1 receptor antagonist) had no effect on scratching behavior induced by TCDD in combination with acetone/olive oil application. With repeated administration for 7 days, chlorpheniramine and tranilast had no effect on scratching behavior, whereas olopatadine significantly inhibited scratching behavior. In addition, only olopatadine significantly inhibited NGF content in the skin. From these findings, it can be concluded that TCDD is not a pruritogen but causes alloknesis (itchy skin) with the simultaneous use of trivial external stimulation. In addition, it was found that drugs which decreased skin NGF contents may inhibit this scratching behavior. PMID:19969104

  6. 7-endo selenocyclization reactions on chiral 3-prenyl and 3-cinnamyl-2-hydroxymethylperhydro-1,3-benzoxazine derivatives. A way to enantiopure 1,4-oxazepanes.

    PubMed

    Nieto, Javier; Andrés, Celia; Pérez-Encabo, Alfonso

    2015-09-14

    Enantiopure 1,4-oxazepane derivatives have been prepared by selenocyclofunctionalization of chiral 3-prenyl- and 3-cinnamyl-2-hydroxymethyl-substituted perhydro-1,3-benzoxazine derivatives. The 7-endo-cyclization occurs in high yields and diastereoselection. The regio- and stereochemistry of the cyclization products was dependent on the substitution pattern of the double bond, the nature of the hydroxyl group and the experimental conditions. PMID:26223944

  7. Thermodynamic properties of a layered S = 7/2 Heisenberg magnet Gd(OH)CO3

    NASA Astrophysics Data System (ADS)

    Orendac, Martin; Ulicny, Martin; Cizmar, Erik; Orendacova, Alzbeta; Chen, Yan-Cong; Meng, Zhao-Sha; Tong, Ming-Liang

    2015-03-01

    Thermodynamic quantities and ESR spectra of Gd(OH)CO3 (I) are reported. The material may be considered to consist of weakly coupled layers with potentially triangular arrangement of exchange paths within each layer. Different bridging groups and distances among Gd3+ ions may be responsible for spatial anisotropy of magnetic coupling. Preliminary analysis of magnetic susceptibility using Curie-Weiss law yielded θ = -1.05 K indicating weak antiferromagnetic coupling and consequently, spin frustration in (I). More detailed simultaneous analysis of specific heat, susceptibility and magnetization studied down to nominally 0.45 K revealed non-negligible role of single-ion anisotropy. Using the model of weakly interacting S =7/2 trimers, the gross features of measured data may be explained while assuming single-ion anisotropy D /kB ~ 0.6 K and effective intratrimer magnetic coupling | J /kB | ~0.3 K. The obtained D value reasonably reproduces the position and shape of ESR line. The performed analysis suggests that magnetism in (I) is governed predominantly by crystal field effects and frustration plays a minor role. Supported by ITMS26220120005 and VEGA 1/0143/13.

  8. 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.

  9. 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.

  10. Entropy and Fermi surface considerations in the nematic phase of Sr3Ru2O7

    NASA Astrophysics Data System (ADS)

    MacKenzie, Andrew

    2010-03-01

    The layered perovskite metal Sr3Ru2O7 has generated interest because of the discovery of nematic-like electrical transport properties at low temperatures [1]. The unusual properties are seen in the vicinity of a metamagnetic quantum critical point. They appear to be the result of the formation of a new phase, which can be observed only in the highest purity single crystals, with mean free paths of several thousand angstroms. Recently, my group has concentrated on understanding this phase and determining its boundaries using thermodynamic probes. In this talk I will review the physics that we believe underlies our observations, and then report on the recent progress, showing how measurements of the specific heat and magneto-caloric effect enable the determination of a complete ``entropy landscape'' of phase formation in the vicinity of a quantum critical point [2]. I will also discuss the discovery of de Haas-van Alphen oscillations within the putative electronic nematic phase [3]. [4pt] [1] R.A. Borzi, S.A. Grigera, J. Farrell, R.S. Perry, S. Lister, S.L. Lee, D.A. Tennant, Y. Maeno & A.P. Mackenzie, Science 315, 214 (2007). [0pt] [2] A.W. Rost, R.S. Perry, J.F. Mercure, A.P. Mackenzie & S.A. Grigera, Science 325, 1360 (2009). [0pt] [3] J.-F. Mercure, S. K. Goh, E. C. T. O'Farrell, R. S. Perry, M. L. Sutherland, A. Rost, S. A. Grigera, R. A. Borzi, P. Gegenwart and A. P. Mackenzie, Phys. Rev. Lett. 103, 176401 (2009).

  11. Frustrated magnetism in doped quasi-triangular lattice materials, Cu2(1-x)Zn2x(OH)3NO3/(C7H15COO)

    NASA Astrophysics Data System (ADS)

    Wu, Jian; Werner, Fletcher; Gangopadhyay, Anup K.; Solin, S. A.

    2010-03-01

    We have performed DC and AC magnetic susceptibility measurements on the spin S=1/2 quasi-triangular lattice materials Cu2(1-x)Zn2x(OH)3NO3/(C7H15COO). The X-ray diffraction experiments reveal that this class of materials has a crystal structure in P21/m space group, in which Cu^2+ and Zn^2+ ions are arranged on a slightly distorted triangular lattice [1]. Cu2(1-)Zn2x(OH)3NO3 with a short inorganic intercalation NO3 group, have a long-range antiferromagnetic order at low temperature. The Neel temperature TN decreases from 11K to 5.6K while the Curie-Weiss temperature increases from -5.1K to +2.8K as the Zn concentration increases from 0 to 65%. After a longer alkanecarboxylate C7H15COO group was introduced into the interlayer space, a spin-glass like behavior in magnetic properties was observed [2]. The value |θcw /TN| is approximately 20, indicating the materials are in a medium level frustrated state. The onset of a ferromagnetic correlation was found in both DC and AC susceptibility data. The interplay of geometrical frustration and the coexistence of ferromagnetic and antiferromagnetic couplings has driven the materials into a glassy ground state. [1] G. Linder, et al., Journal of Solid State Chemistry (1995) [2] M. A. Girtu et al, Phys Rev B 61,4117(2000).

  12. 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.

  13. 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.

  14. 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.

  15. Enhanced cycle stability at high rate and excellent high rate capability of La0.7Sr0.3Mn0.7Co0.3O3-coated LiMn2O4

    NASA Astrophysics Data System (ADS)

    Shi, Ting; Dong, Yue; Wang, Chun-Mei; Tao, Fen; Chen, Li

    2015-01-01

    La0.7Sr0.3Mn0.7Co0.3O3-coated spinel LiMn2O4 with excellent cycle stability and high rate capability is successfully prepared by a sol-gel method. The 3 wt.% La0.7Sr0.3Mn0.7Co0.3O3-coated LiMn2O4 shows the optimum electrochemical performance. It can deliver 101 mAh g-1 at 10 C even after 100 cycles with a capacity retention of 93.5%. In contrast, the bare LiMn2O4 delivers 83.6 mAh g-1 at the same condition, only 84.5% capacity left. The rate capability of 3 wt.% La0.7Sr0.3Mn0.7Co0.3O3-coated LiMn2O4 is also obviously enhanced, especially at high rates (10 C, 20 C and 30 C). It can deliver 74.3 mAh g-1 at 30 C which is much higher than that of the bare sample (47.2 mAh g-1). The bare and coated LiMn2O4 samples are studied with various techniques. Both powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements demonstrate the existence of the La0.7Sr0.3Mn0.7Co0.3O3, and it has no influence on the crystal structure of the pristine LiMn2O4. Transmission electron microscopy (TEM) shows that La0.7Sr0.3Mn0.7Co0.3O3 coating layer with good crystallinity can cover the surface of LiMn2O4 to form a core-shell structure. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) demonstrate that the coating layer can improve the kinetics of electrodes.

  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. Transport Studies on Nanometer Thick YBa2Cu3O7-δ Multilayers Using Y0.4Pr0.6Cu3O7 and PrBa2(Cu0.8Ga0.2)3O7 as Buffer Layers

    NASA Astrophysics Data System (ADS)

    Wu, Ke; Tipparach, Udom.; Chen, Tar-Pin; Li, Qi; Zeng, X. H.; Wert, E.; Wagner, John. L.; Chen, Quark Y.; Wang, J. T.; Yang, Hong-Chang; Horng, Herng-Er

    We have fabricated PrBa2[Cu1-xGax]3O7 (PBGCO) ceramic samples for x = 0.05, 0.10, 0.15 and 0.20. The electrical resistivities of these samples are many orders of magnitude higher than that of PrBa2Cu3O7 (Pr123) while the other physical properties remain much the same. PBGCO therefore may be a possible buffer layer for YBa2Cu3O7-δ (Y123) superlattices/multilayers. For this reason YBa2Cu3O7-δ/PrBa2(Cu0.8Ga0.2)3O7 (Y123/PBCGO) and YBa2Cu3O7-δ/Y0.4Pr0.6Ba2Cu3O7 (Y123/YPBCO) superlattices were fabricated and their transport properties were studied. It is found that although PBGCO is better for insulating Y123 films in trilayers, inter-Y123 layer coupling exists between separated Y123 layer.

  18. 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.

  19. Solubility of 2,3,7,8-TCDD (tetrachlorodibenzo-p-dioxin) in contaminated soils

    SciTech Connect

    Jackson, D.R.; Roulier, M.H.; Grotta, H.M.; Rust, S.W.; Warner, J.S.

    1986-01-01

    Soils from ten sites contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were investigated in aqueous batch and intact core leaching studies to determine water/soil partition coefficients (K/sub p/) for TCDD and factors affecting the K/sub p/. TCDD content in soils ranged from 8 to 26,000 ng/g. For the batch extractions, TCDD concentrations in solution ranged from 0.1 to 56 ng/L; 79% of the values were 2.0 ng/L or less. For the intact cores, TCDD concentrations in leachate ranged from 0.1 to 14 ng/L; 81% of the values were 2.0 ng/L or less. The amount of TCDD in the soil and the amount of TCDD in the water extracts were strongly related to the total solvent-extractable organic matter (SEOM) in soil and the halogenated semi-volatiles in the solvent-extractable fraction. These results suggest that co-contaminants in the wastes along with the TCDD were sorbed to the soil and that these materials as a group greatly influence the partitioning of TCDD between soil and water in these contaminated soils.

  20. 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.

  1. Thermal denitrogenation of 7-isopropylidene-2,3-diaza-norbornene: formation of substituted 3-methylene-(1,4)-pentadienes.

    PubMed

    Bozkaya, Uğur; Özkan, Ilker

    2012-11-01

    A theoretical study of the thermal denitrogenation of 7-isopropylidene-2,3-diaza-norbornene is carried out by employing density functional theory and high level ab initio methods, such as the complete active space self-consistent field, multi-reference second-order Møller-Plesset perturbation theory, and coupled-cluster singles and doubles with perturbative triples. In all computations Pople's polarized triple-ζ split valence basis set, 6-311G(d,p), is utilized. The potential energy surface for the relevant system is explored to provide a theoretical account for the formation of trienes (major products). For this purpose, a mechanism has been proposed and theoretically studied. The rate constant for each isomerization reaction is computed using the transition state theory. The simultaneous first-order ordinary-differential equations are solved numerically for the considered system to obtain time-dependent concentrations, hence the product distributions at a given temperature. Our results demonstrate that E- and Z-2-methyl-3-ethylidene-1,4-pentadienes are formed via a reaction path originating from 3-isopropylidene-1,4-pentadiene. The result of kinetic analysis agrees well with the experimental observations of Berson et al. (M. R. Mazur, S. E. Potter, A. R. Pinhas and J. A. Berson, J. Am. Chem. Soc., 1982, 104, 6823-6824). Further, the computed percentage of trienes is in general agreement with experiment. Therefore, we conclude that our proposed mechanism satisfactorily explains the experimental observations. PMID:22992761

  2. 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

  3. The solubility and site preference of Fe3+ in Li7-3xFexLa3Zr2O12 garnets

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

    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 Li7-3xFexLa3Zr2O12 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 Li7-3xFexLa3Zr2O12 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.

  4. 2,2,4-Trimethyl-7-nitro-2,3-dihydro-1H-1,5-benzodiazepin-5-ium perchlorate

    PubMed Central

    Mehdi, Sayed Hasan; Sulaiman, Othman; Ghalib, Raza Murad; Yeap, Chin Sing; Fun, Hoong-Kun

    2010-01-01

    In the title mol­ecular salt, C12H16N3O2 +·ClO4 −, the nitro group is close to being coplanar with the benzene ring [dihedral angle = 8.1 (3)°]. The seven-membered ring has a maximum deviation of 0.502 (3) Å at the C atom between the dimethyl- and methyl-substituted C atoms. In the crystal, the components are linked into infinite sheets lying parallel to the bc plane by N—H⋯O and C—H⋯O hydrogen bonds. A short O⋯N contact of 2.896 (4) Å occurs within the sheets and a short O⋯O contact of 2.608 (4) Å occurs between the sheets. PMID:21588044

  5. 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.

  6. Density functional theory calculations of UO2 oxidation: evolution of UO(2+x), U4O(9-y), U3O7, and U3O8.

    PubMed

    Andersson, D A; Baldinozzi, G; Desgranges, L; Conradson, D R; Conradson, S D

    2013-03-01

    Formation of hyperstoichiometric uranium dioxide, UO2+x, derived from the fluorite structure was investigated by means of density functional theory (DFT) calculations. Oxidation was modeled by adding oxygen atoms to UO2 fluorite supercells. For each compound ab initio molecular dynamics simulations were performed to allow the ions to optimize their local geometry. A similar approach was used for studying the reduction of U3O8. In agreement with the experimental phase diagram we identify stable line compounds at the U4O9-y and U3O7 stoichiometries. Although the transition from fluorite to the layered U3O8 structure occurs at U3O7 (UO2.333) or U3O7.333 (UO2.444), our calculated low temperature phase diagram indicates that the fluorite derived compounds are favored up to UO2.5, that is, as long as the charge-compensation for adding oxygen atoms occurs via formation of U(5+) ions, after which the U3O8-y phase becomes more stable. The most stable fluorite UO2+x phases at low temperature (0 K) are based on ordering of split quad-interstitial oxygen clusters. Most existing crystallographic models of U4O9 and U3O7, however, apply the cuboctahedral cluster. To better understand these discrepancies, the new structural models are analyzed in terms of existing neutron diffraction data. DFT calculations were also performed on the experimental cuboctahedral based U4O9-y structure, which enable comparisons between the properties of this phase with the quad-interstitial ones in detail. PMID:23406007

  7. The intersublattice exchange interactions in the R 2Co 7B 3 compounds (R = heavy rare earth)

    NASA Astrophysics Data System (ADS)

    Kowalczyk, A.

    1997-07-01

    The experimental values of Curie temperatures of hexagonal R 2Co 7B 3 (R = heavy rare earth) compounds are used to calculate the effective intersublattice exchange interactions, JRCo, between R and Co sublattices. A mean field approximation is used. The compounds belong to the R n+1Co 3 n+5B 2 n family. The R 2Co 7B 3 is a combination of CaCu 5 and CeCo 3B 2-type structures. The JRCo has a tendency to decrease with increasing atomic number of the rare earth partner. A similar tendency has been found for other Fe and Co-based compounds.

  8. 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. PMID:25773989

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

    PubMed Central

    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

    2015-01-01

    Background Spinocerebellar Ataxias (SCAs) belong to polyglutamine repeat disorders and are characterized by a predominant atrophy of the cerebellum and the pons. Methods Proton magnetic resonance spectroscopy (1H MRS) using an optimised 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), SCA7 (n = 12) and healthy controls (n = 33). Results Compared to controls, patients displayed lower total N-acetylaspartate and, to a lesser extent, lower glutamate, reflecting neuronal loss/dysfunction, while the glial marker, myo-inositol, was elevated. Patients also showed higher total creatine as reported in Huntington disease, another polyglutamine repeat disorder. There was a strong correlation 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-inositol) 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. Conclusion 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. PMID:25773989

  10. 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.

  11. Microwave microstrip resonator measurements of Y1Ba2Cu3O(7-x) and Bi2Sr2Ca1Cu2O(8-y) thin films

    NASA Technical Reports Server (NTRS)

    Lichtenberg, Christopher L.; Wosik, Jaroslaw; Davis, Matthew; Wolfe, J. C.

    1989-01-01

    Radio frequency (RF) surface resistance measurement experiments on high T(sub c) thin films were performed. The method uses a microstrip resonator comprising a top gold conductor strip, an alumina dielectric layer, and a separate superconductivity ground plane. The surface resistance of the superconducting ground plane can be determined, with reference to a gold calibration standard, from the measured quality factor of the half-wave resonator. Initial results near 7 GHz over the temperature range from 25 to 300 K are presented for YBa2Cu3O(7-x) and Bi2Sr2CaCu2O(8-y) thin film samples deposited by an electron beam flash evaporation process. The RF surface resistance at 25 K for both materials in these samples was found to be near 25 milliohms.

  12. Structure and Stoichiometry in Supervalent Doped Li7La3 Zr2O12

    DOE PAGESBeta

    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

  13. Wrinkling of YBa2Cu3O7-x film prepared by trifluoroacetate metal organic deposition

    NASA Astrophysics Data System (ADS)

    Jin, L. H.; Li, C. S.; Yu, Z. M.; Feng, J. Q.; Zhang, S. N.; Sulpice, A.; Wang, Y.; Zhang, P. X.

    2015-11-01

    YBa2Cu3O7-x (YBCO) films with wrinkles have been fabricated on LaAlO3(1 0 0) substrates by trifluoroacetate metal organic deposition (TFA-MOD). The decomposition behavior of YBCO-TFA gel and the formation mechanism of wrinkles were analyzed by thermal analysis, Fourier transform infrared spectroscopy, and atomic force microscopy. The effects of wrinkles on the texture, microstructure and critical current density of the final crystallized film were also investigated by X-ray diffraction and scanning electron microscopy. The heating rate in the decomposition process was a crucial parameter to control the wavelength and wave amplitude of wrinkles on the surface of YBCO precursor film. Furthermore, the wrinkles of precursor films were transformed into the ridges of crystallized films during the crystallization process. Large ridges resulted in the degradation of texture of YBCO crystallized films. The decrease of critical current density (Jc) of YBCO crystallized films could be ascribed to the formation of ridges, the segregated phases and the degradation of texture. It suggested that the smooth morphology of YBCO precursor films would be beneficial to the enhancement of Jc value.

  14. 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

  15. Chemistry of the hexaborane(10) analogue (PPh{sub 3}){sub 2}(CO)IrB{sub 5}H{sub 8}: Formation and characterization of the heterobimetallaheptaboranes 1,1,1-(CO){sub 3}-2,2-(CO){sub 2}-2,4-(PPh{sub 3}){sub 2-closo-}-1,2-FeIrB{sub 5}H{sub 4} and 2-(CO)-2,2-(PPh{sub 3}){sub 2}-7-Cl-7-(PMe{sub 2}Ph)-nido-2,7-IrPtB{sub 5}H{sub 7}

    SciTech Connect

    Bould, J.; Rath, N.P.; Fang, H.; Barton, L.

    1996-03-27

    The chemistry of the hexaborane(10) analogue (PPh{sub 3}){sub 2}(CO)IrB{sub 5}H{sub 8} (4) has been investigated. The two standard reactions in which metal-containing moieties may be incorporated into the B{sub 6}H{sub 10} cage find success when applied to the iridahexaborane (4). The reaction of Fe{sub 2}(CO){sub 9} with (PPh{sub 3}){sub 2}(CO)IrB{sub 5}H{sub 8} in C{sub 6}H{sub 6} solution affords 1,1,1-(CO){sub 3}-2,2-(CO){sub 2}-2,4-(PPh{sub 3}){sub 2-closo}-1,2-FeIrB{sub 5}H{sub 4} (1) in moderate (28.5%) yield. Except for carborane derivatives, 1 is the first pentagonal bipyramidal metallaheptaborane to be structurally characterized. Compound 1 was identified by NMR, IR, and high-resolution mass spectroscopy and by a single-crystal X-ray diffraction study. Treatment of a THF solution of the sodium anion salt of 4, Na[(PPh{sub 3}){sub 2}(CO)IrB{sub 5}H{sub 7}], with [Pt(PMe{sub 2}Ph)Cl{sub 2}]{sub 2} in Ch{sub 2}Cl{sub 2} affords yellow solid 2-(CO)-2,2-(PPh{sub 3}){sub 2}-7-Cl-7-(PM3{sub 2}-Ph)-nido-2,7-IrPtB{sub 5}H{sub 7} (2) in 5% yield. 2 is identified similarily. It exists as a nido seven-vertex cluster formally derived by removal of a vertex of connectivity 5 from a closed triangulated dodecahedral polyhedron. 2 is two skeletal electrons short of the electron count for a classical nido cluster, and it is compared to systems with related structures and also to other systems containing the Pt moiety functioning as a two-orbital two-electon donor.

  16. Theoretical Study of Mechanism and Regioselectivity of 1,3-dipolar Cycloaddition of N-[methyl]-C-[5-nitro-2-furyl] Nitrilimine with Dimethyl 7-oxabicyclo[2,2,1]hepta-2,5-diene-2,3-dicarboxylate

    NASA Astrophysics Data System (ADS)

    Moeinpour, Farid

    2010-04-01

    The mechanism and regioselectivity of 1,3-dipolar cycloaddition of N-[methyl]-C-[5-nitro-2-furyl] nitrilimine with dimethyl 7-oxabicyclo[2,2,1]hepta-2,5-diene-2,3-dicarboxylate were investigated using activation energy calculations and density functional theory-based reactivity indexes. The reaction proceeds by an asynchronous concerted mechanism. The calculations are performed at the B3LYP/6-31G(d) level of theory and the obtained results are in agreement with experimental outcome.

  17. Novel methyl substituted 1-(5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanones are P2X7 antagonists.

    PubMed

    Rudolph, Dale A; Alcazar, Jesus; Ameriks, Michael K; Anton, Ana Belen; Ao, Hong; Bonaventure, Pascal; Carruthers, Nicholas I; Chrovian, Christa C; De Angelis, Meri; Lord, Brian; Rech, Jason C; Wang, Qi; Bhattacharya, Anindya; Andres, Jose Ignacio; Letavic, Michael A

    2015-08-15

    The optimization efforts that led to a novel series of methyl substituted 1-(5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanones that are potent rat and human P2X7 antagonists are described. These efforts resulted in the discovery of compounds with good drug-like properties that are capable of high P2X7 receptor occupancy in rat following oral administration, including compounds 7n (P2X7 IC50 = 7.7 nM) and 7u (P2X7 IC50 =7 .7 nM). These compounds are expected to be useful tools for characterizing the effects of P2X7 antagonism in models of depression and epilepsy, and several of the compounds prepared are candidates for effective P2X7 PET tracers. PMID:26099534

  18. [2](1,3)Adamantano[2](2,7)pyrenophane: A Hydrocarbon with a Large Dipole Moment.

    PubMed

    Kahl, Paul; Wagner, J Philipp; Balestrieri, Ciro; Becker, Jonathan; Hausmann, Heike; Bodwell, Graham J; Schreiner, Peter R

    2016-08-01

    The fusion of the sp(3) -hybridized parent diamondoid adamantane with the sp(2) -hybridized pyrene results in a hybrid structure with a very large dipole moment which arises from bending the pyrene moiety. Presented herein is the synthesis, study of the electronic and optical properties, as well as the dynamic behavior of this new hydrocarbon. PMID:27364983

  19. 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.

  20. Cancer risk-specific dose estimate for 2,3,7,8-TCDD. Draft report

    SciTech Connect

    Not Available

    1988-06-01

    This draft report focuses on the hazard identification and dose-response assessment for the potential human carcinogenicity of the chemical. The objective of the report is to determine if EPA's 1985 cancer risk assessment for polychlorinated dibenzo-p-dioxins should be modified in light of recent data, alternative risk-assessment methods, or alternative interpretations of data on the chemical. The report concludes that (1) the 1985 assessment that associates a 0.006 pk/kg/day dose with a plausible upper-bound increased cancer risk of one in a million should be reconsidered, and (2) a change to a 0.1 pg/kg/day dose as a plausible upper bound associated with an increased lifetime risk of one in a million is consistent with the available data and theories, and represents a reasonable science policy for the Agency. Also, appendices A through F to the document contain important background information on a broad range of issues related to 2,3,7,8-TCDD including quantitative implications (A), epidemiology (B and D), reproductive and developmental toxicity (C), immunotoxicity (E), and mechanisms of action (F).

  1. 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

  2. Tuning Vortex Creep in Irradiated YBa2Cu3O7-δ Coated Conductors

    NASA Astrophysics Data System (ADS)

    Eley, Serena; Kihlstrom, Karen; Holleis, Sigrid; Leroux, Maxime; Rupich, Martin; Miller, Dean; Kayani, Asghar; Welp, Ulrich; Kwok, Wai-Kwong; Civale, Leonardo

    YBa2Cu3O7-δ coated conductors (CCs) show non-monotonic changes in the temperature-dependent creep rate, S (T) , due to mixed pinning landscapes comprised of twin boundaries, planar defects, point defects, and nanoparticle precipitates. Notably, in low fields, there is a conspicuous dip in S as T increases from ~20K to ~65K. The source of this dip is poorly understood. Moreover, pinning landscapes that are favorable for high critical currents, Jc, are not necessarily optimal for low S. We have found that, though oxygen irradiation introduces few-nm-sized defects that result in significant increases in Jc, it is detrimental to creep, increasing S (reducing the dip depth) for T > 20K. Understanding the source of this dip is crucial to engineering pinning landscapes that concurrently promote high Jc and low S. To this end, we study changes in S (T) as we tune the ratio of smaller (point to few-nm-sized) defects to larger nanoparticles in an oxygen-irradiated CC by annealing in O2 at 250°C to 600°C. We observe a steady decrease in S (T > 20K) with increasing annealing temperature. This suggests that pre-existing nanoparticle precipitates are likely responsible for the dip in S (T) , and underlines the fact that the effects of defects are not additive, but rather can be competitive.

  3. 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.

  4. 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

  5. Thyroid hormones modulate the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

    SciTech Connect

    Rozman, K.; Rozman, T.; Scheufler, E.; Pazdernik, T.; Greim, H.

    1985-01-01

    The first experiment is a continuation of a study reported previously. In this experiment, 60 male Sprague-Dawley rats were divided into 6 equal groups. Four groups of rats were thyroidectomized by 3 mCi Na/sup 131/ l/kg rat. Five weeks later 2 of the thyroidectomized and 1 of the nonthyroidectomized groups of rats received ip 100 ..mu..g TCDD/kg body weight in corn oil/acetone, whereas 3 corresponding groups of rats served as vehicle controls. Two days after dosing and every 7 d thereafter, 1 thyroidectomized control group and 1 thyroidectomized TCDD-dosed group were given ip 105 ..mu..g t/sub 4//kg body weight. The course of TCDD toxicity was similar in nonthyroidectomized and thyroidectomized T/sub 4/-treated rats, but was different in thyroidectomized animals without T/sub 4/ replacement therapy. At d 90 after TCDD dosage, mortality was still lower and the mean time to death was increased (p < 0.01) in this group of rats compared to nonthyroidectomized or thyroidectomized T/sub 4/-treated rats. However, administration of T/sub 4/ starting at d 91 after dosing with TCDD resulted within 2 wk in the same final mortality in thyroidectomized rats as in nonthyroidectomized or thyroidectomized T/sub 4/-treated animals, indicating that thyroid hormones modulate the time course of the wasting syndrome but do not affect the ultimate mortality figure. In the second experiment the three vehicle control groups of the first experiment were used. Nonthyroidectomized vehicle controls and thyroidectomized T/sub 4/-treated controls were maintained as before, whereas thyroidectomized controls received T/sub 3/ at 5 ..mu..g/kg daily. One month later each rat was dosed with TCDD at 100 ..mu..g/kg in corn oil/acetone. Toxicity of TCDD was similar in nonthyroidectomized, thyroidectomized T/sub 4/-treated, and thyroidectomized T/sub 3/-treated rats as judged by mortality, body weight, and food intake, indicating no difference between T/sub 3/ and T/sub 4/ in the modulation of TCDD

  6. Synthesis and pharmacological properties of 1-(4-substituted)butyl derivatives of amides of 7-methyl-3-phenyl-2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimi dine-5 -carboxylic acid.

    PubMed

    Sladowska, H; Sieklucka-Dziuba, M; Rejdak, R; Kleinrok, Z

    2000-01-01

    The synthesis of 1-(4-substituted)butyl derivatives of amides of 7-methyl-3-phenyl-2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimid ine-5- carboxylic acid and the results of the preliminary pharmacological screening are described in this paper. Some of them showed a weak analgesic action and caused suppression of the spontaneous locomotor activity of mice. PMID:10755225

  7. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) enhances placental inflammation

    PubMed Central

    Peltier, Morgan R.; Arita, Yuko; Klimova, Natalia G.; Gurzenda, Ellen M.; Koo, Hchi-Chi; Murthy, Amitasrigowri; Lerner, Veronica; Hanna, Nazeeh

    2013-01-01

    Preterm birth is a leading cause of perinatal morbidity and mortality that is often associated with ascending infections from the lower genital tract. Recent studies with animal models have suggested that developmental exposure to the environmental toxin 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can increase the risk of preterm birth in the offspring. How TCDD may modify placental immunity to ascending infections is unclear. Therefore, we studied the effects of TCDD treatment on basal and Escherichia coli-stimulated cytokine production by placental explants. Cultures of second-trimester placentas were treated with up to 40 nM TCDD for 72 h and then stimulated with 107 CFU/ml E. coli for an additional 24 h. Concentrations of cytokines and PGE2 were measured in conditioned medium by immunoassay. TCDD exposure increased mRNA levels of IL-1β by unstimulated cultures, but no effects on protein levels of this cytokine were detected. TNF-α production was unaffected by TCDD for unstimulated cultures, but pre-treatment with 40 nM TCDD significantly increased E. coli-stimulated TNF-α production. Both basal and bacteria-stimulated PGE2 and COX-2 gene expression were enhanced by TCDD pretreatment. In contrast, production of the anti-inflammatory cytokine, IL-10, was reduced by TCDD pretreatment for both unstimulated and E. coli-stimulated cultures. No effect of TCDD on the viability of the cultures was detected. These results suggest that TCDD exposure may shift immunity to enhance a proinflammatory phenotype at the maternal–fetal interface that could increase the risk of infection-mediated preterm birth. PMID:23642494

  8. 3,3-Bis-(4-hydroxyphenyl)-7-methyl-2-indolinone (BHMI), the active metabolite of the laxative sulisatin.

    PubMed

    Moretó, M; Goñalons, E; Mylonakis, N; Giráldez, A; Torralba, A

    1979-01-01

    The disodium salt of the sulphuric diester of 3,3-bis-(4-hydroxyphenyl)-7-methyl-2-indolinone (sodium sulisatin, Laxitex), a synthetic laxative with two phenolic groups esterified with sulfate, has been studied in order to find out if its laxative properties may be attributed to the unaltered compound or to its diphenolic derivative BHMI. We first studied the effect of homogenates of the gastrointestinal tract of rats and of rat cecal content of the hydrolysis of sulfate ester bonds of sulisatin. Results show that sulisatin can be hydrolyzed by cecal content while homogenates of stomach, small intestine and large intestine have no hydrolytic effect. Sulisatin is also a substrate of arylsulfate sulphohydrolase obtained from the snail Helix pomatia. The unaltered drug has no effect on the intestinal motility since it does not change the intestinal transit speed in rats pretreated with neomycin sulfate. Sulisatin (1.5, 3 and 6 mg) is unable to inhibit water absorption in rat colon while small amounts of BHMI (15 and 30 micrograms) may inhibit it significantly. It is concluded that sulisatin passes unaltered through the small intestine and is hydrolyzed in the large intestine by the intestinal microflora to its diphenolic derivative BHMI, which is responsible for the laxative activity of the drug. PMID:583222

  9. Induced Ferromagnetism at Interfaces between BiFeO3 and YBa2Cu3O7

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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 the 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, into a resultant generic phase diagram. The emergence of interfacial ferromagnetism should have implications to electronic and transport properties. This work was supported by U.S. DOE at LANL under Contract No. DE-AC52-06NA25396, LANL LDRD-DR Program, and in part by the Center for Integrated Nanotechnologies, a U.S. DOE Office of Basic Energy Sciences user facility.

  10. Review of plant uptake of 2,3,7,8-TCDD from soil and potential influences of bioavailability

    SciTech Connect

    Kew, G.; Schaum, J.L.; White, P.; Evans, T.T.

    1989-08-01

    Volatilization of 2,3,7,8-TCDD from soil and resorption on foliage represents a significant route of contamination. Some studies indicate low-level uptake, translocation from roots to foliage and transpiration from foliage, while one shows more than 95% of 2,3,7,8-TCDD associated with edible fruits and with tubers is found in peels. Differences in bioavailability from different soils might account for some inconsistencies between existing studies, suggesting additional information useful in reporting future work.

  11. Strong flux pinning enhancement in YBa2Cu3O7-x films by embedded BaZrO3 and BaTiO3 nanoparticles

    NASA Astrophysics Data System (ADS)

    Ding, Fa-Zhu; Gu, Hong-Wei; Zhang, Teng; Wang, Hong-Yan; Qu, Fei; Qiu, Qing-Quan; Dai, Shao-Tao; Peng, Xing-Yu

    2013-07-01

    YBa2Cu3O7-x (YBCO) films with embedded BaZrO3 and BaTiO3 nanoparticles were fabricated by metalorganic deposition using trifluoroacetates (TFA-MOD). Both X-ray diffraction and transmission electron microscopy revealed that these BaZrO3 and BaTiO3 nanoparticles had random orientations and were distributed stochastically in the YBCO matrix. The unique combined microstructure enhances the critical current density (Jc) of the BaZrO3/BaTiO3 doped-YBCO films, while keeping the critical transition temperature (Tc) close to that in the pure YBCO films. These results indicate that BaZrO3 and BaTiO3 nanoparticles provide strong flux pinning in YBCO films.

  12. 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.

  13. Crystal structure of 7-[(2E)-2-benzyl­idene-3-oxobut­oxy]-4-methyl-2H-chromen-2-one

    PubMed Central

    Caracelli, Ignez; Zukerman-Schpector, Julio; Moran, Paulo J. S.; de Paula, Bruno R. S.; Tiekink, Edward R. T.

    2015-01-01

    Two independent mol­ecules (A and B) comprise the asymmetric unit of the title compound, C21H18O4. There are significant conformational differences between the mol­ecules relating in particular to the relative orientation of the 3-oxo-2-(phenyl­methyl­idene)but­oxy substituent with respect to the superimposable chromen-2-one residues. To a first approximation, the substituents are mirror images; both are approximately perpendicular to the chromen-2-one fused ring system with dihedral angles of 88.50 (7) (A) and 81.96 (7)° (B). Another difference between the independent mol­ecules is noted in the dihedral angles between the adjacent phenyl and but-3-en-2-one groups of 8.72 (12) (A) and 27.70 (10)° (B). The conformation about the ethene bond in both mol­ecules is E. The crystal packing features C—H⋯O, C—H⋯π(ar­yl) and π–π [Cg⋯Cg = 3.6657 (8) and 3.7778 (8) Å] stacking inter­actions, which generate a three-dimensional network. PMID:26029424

  14. A comparative study of Cr7C3, Fe3C and Fe2B in cast iron both from ab initio calculations and experiments

    NASA Astrophysics Data System (ADS)

    Xiao, B.; Xing, J. D.; Feng, J.; Zhou, C. T.; Li, Y. F.; Su, W.; Xie, X. J.; Cheng, Y. H.

    2009-06-01

    The ground state properties of three compounds, Cr7C3, Fe3C and Fe2B, are investigated using ab initio calculations based on density functional theory. Formation enthalpy values indicate that Cr7C3 is the most stable crystal among the three compounds. Fe3C is metastable which has a positive heat of formation value. The calculated bulk modulus, shear modulus and Young's modulus value of Cr7C3 are 311 GPa, 143.8 GPa and 374 GPa, respectively. The bulk modulus values of Fe2B and Fe3C are 194 GPa and 258 GPa. We also find that both the hardness and the stiffness of the Cr7C3 type carbides can be improved by doping with B, W, Mo, etc. The bulk modulus of transition metal doped Fe2B is considerably higher than pure Fe2B. The electronic structures of Fe2B and Fe3C are ferromagnetic and the evaluated average magnetic moment of Fe is 2.09μB/atom for Fe3C and 2.02μB/atom for Fe2B, respectively. Micro-indentation test results indicate that Cr7C3 is the hardest phase among the three phases and shows excellent wear resistance performance under three-body abrasive experiments. The experimental results are in agreement with the theoretical prediction that Cr7C3 is the best both in stability and mechanical performance.

  15. 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

  16. 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

  17. 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(κ(2)-diphosphine)(μ-edt)2] as Proton Reduction Catalysts.

    PubMed

    Rahaman, Ahibur; Ghosh, Shishir; Unwin, David G; Basak-Modi, Sucharita; Holt, Katherine B; Kabir, Shariff E; Nordlander, Ebbe; Richmond, Michael G; Hogarth, Graeme

    2014-03-24

    The mixed-valence triiron complexes [Fe3(CO)7-x (PPh3) x (μ-edt)2] (x = 0-2; edt = SCH2CH2S) and [Fe3(CO)5(κ(2)-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(κ(2)-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 atoms

  18. 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.

  19. 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.

  20. Investigations on the synthesis and properties of new derivatives of ethyl 3H-2-imino-7-methyl-4-oxopyrido [3,2-e]-1,3-thiazine-6-carboxylate and isomeric compounds.

    PubMed

    Sladowska, H; Zawisza, T

    1982-04-01

    Condensation of diethyl 2-chloro-6-methylpyridine-3,5-dicarboxylate (IV) with thiourea and alkyl or alkenyl N-mono- and N,N'-disubstituted thioureas gives mainly the corresponding derivatives of ethyl 3H-2-imino-7-methyl-4-oxopyrido [3,2-e]-1,3-thiazine-6-carboxylate (VI-XII). As by-products isomeric derivatives of ethyl 7-methyl-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrido [2,3-d) pyrimidine-6-carboxylate (XIII-XVIII) are formed. PMID:7084447

  1. 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

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

    DOE PAGESBeta

    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

  3. Coherent Voltage Oscillations in Superconducting Polycrystalline Y1Ba2Cu3O7-x

    NASA Astrophysics Data System (ADS)

    Altinkok, A.; Yetiş, H.; Olutaş, M.; Kiliç, K.; Kiliç, A.; Çetin, O.

    2006-06-01

    We have investigated the voltage response of superconducting polycrystalline bulk Y1Ba2Cu3O7-x (YBCO) material to a bidirectional square wave current with long periods and dc current by means of the evolution of the voltage-time (V-t) curves near the critical temperature. In a well-defined range of amplitudes and periods of driving current, and temperatures, it was observed that a non-linear response to bidirectional square wave current rides on a time independent background voltage value and manifests itself as regular sinusoidal-like voltage oscillations. It was found that the non-linear response disappears when the bidirectional current was switched to dc current. The spectral content of the voltage oscillations analyzed by the Fast Fourier Transform of the corresponding V-t curves revealed that the fundamental harmonics is comparable to the frequency of bidirectional square wave current. The coherent voltage oscillations were discussed mainly in terms of the dynamic competition between pinning and depinning together with the disorder in the coupling strength between the superconducting grains (i.e Josephson coupling effects). The density fluctuations and semi-elastic coupling of the flux lines with the pinning centers were also considered as possible physical mechanisms in the interpretation of the experimental results.

  4. Shock wave induced changes in superconductivity in YBa2Cu3O(7-delta)

    NASA Astrophysics Data System (ADS)

    Murr, L. E.; Niou, C. S.; Jin, S.; Tiefel, T. H.; James, A. C. W. P.

    1989-10-01

    Shock wave loading produced significant changes in superconductivity in sintered YBa2Cu3O(7-delta) causing a broad transition with Tc (R = 0) around 40 K. The normal-state resistivity increased by 20-50 times with the rho-T curve exhibiting a semiconducting behavior. Comparative thermogravimetric analysis, however, indicated no loss of oxygen in the shock-loaded sample, and X-ray powder diffraction analysis showed no major changes except for slight line broadening. The observed semiconductive behavior and degradation in superconductivity is thus attributed to a rather subtle disturbance in crystal structure, the nature of which is not clearly understood at present. The lack of sufficient recovery in Tc by post-shock oxygen processing at temperatures as high as 750 C and subsequent cooling implies that the atomic-scale disturbance may not necessarily be related to a simple oxygen disorder. Such defects, if controlled properly, may be advantagenously turned into desirable flux-pinning sites for improved critical currents.

  5. 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.

  6. Methods for aquatic ecological risk assessments of 2,3,7,8-TCDD and related chemicals

    SciTech Connect

    Cook, P.; Erickson, R.; Spehar, R.; Bradbury, S.; Ankley, G.; Burkhard, L.

    1994-12-31

    As part of USEPA`s ongoing assessment of the aquatic ecological risk of 2,3,7,8-TCDD and related polyhalogenated aromatic chemicals, available information on bioaccumulation and effects of these chemicals was analyzed to determine major uncertainties and approaches for addressing these uncertainties. Reported effects vary widely among chemicals, exposure conditions, and organisms. Considerable variability can be explained by relating effects to chemical accumulation, so measurement or prediction of chemical concentrations in tissues of aquatic organisms is essential in assessing risk. However, many of the most toxic of these compounds are difficult to measure in water and have uncertain activities based on available octanol-water partition coefficients. The biota-sediment accumulation factor (BSAF), through direct measurement of the fugacity gradient between sediments and organisms, can be used to predict bioaccumulation. When TCDD toxicity is expressed on the basis of accumulation, fish early-life-stage survival appears to be the most sensitive endpoint for aquatic organisms. For aquatic-associated wildlife, limited data requires that dose be referenced to TCDD concentration in food. Reproductive effects on certain fish-eating birds and mammals are of greatest concern. Such effect concentrations can be used to assess risk based on fish contamination surveys or, when combined with BSAFs and BAFs, on sediment and water concentrations. However, such assessments are made uncertain by limited toxicity information for certain taxonomic groups and endpoints.

  7. Public health response to 2,3,7,8-TCDD environmental contamination in Missouri

    SciTech Connect

    Stehr, P.A.; Forney, D.; Stein, G.; Donnell, H.D.; Falk, H.; Hotchkiss, R.; Spratlin, W.A.; Sampson, E.; Smith, S.J.

    1985-05-01

    In 1971, waste oil containing 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was sprayed for dust control on a number of residential, recreational, and work areas in Missouri. In several of them, the level and extent of environmental contamination were not known until late 1982 or 1983. Extrapolation from existing toxicological data indicated the potential for substantial adverse health effects in highly exposed populations. As a result, the Missouri Division of Health and the Centers for Disease Control initiated close collaboration with the Environmental Protection Agency (EPA) on review and evaluation of environmental data, the development of health advisories to EPA on the need for remedial or preventive actions at specific contaminated sites, a health education effort for the medical community and general public, establishment of a dermatological screening clinic, establishment of a central listing of potentially exposed persons through administration of a health effects survey questionnaire, and a pilot medical study of a ''highest risk'' cohort. Strategies for additional interventions will continue to be based on findings derived from this first phase of the investigation.

  8. Generation of thick Ba2YCu3O7 films by aerosol deposition

    NASA Astrophysics Data System (ADS)

    Kodas, T. T.; Engler, E. M.; Lee, V. Y.

    1989-05-01

    Thick superconducting films were fabricated by producing high-purity Ba2YCu3O7 particles by aerosol decomposition in a gaseous flow system, depositing the particles directly from the gas phase onto surfaces by thermophoresis, and then sintering and annealing the deposited particulate films in an oxygen flow. Particulate films with thicknesses of 1 mm were deposited on the inside surfaces of copper tubes and sintered to provide uniform adherent coatings with sharp superconducting transitions above 91 K. High-purity powders based on the Bi-Sr-Ca-Cu-O and Tl-Ca-Ba-Cu-O systems were also produced and sintered to form bulk ceramics with transitions at 80 and 110 K, respectively, suggesting that the process is general and can be used for a variety of materials. Advantages of the process include the ease of obtaining the correct oxygen content and the ability to fabricate thick films of fine grained material while minimizing exposure to carbon and other contaminants.

  9. 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.

  10. Microstructure and superconductivity of highly ordered YBa(2)Cu(3)O(7-δ) nanowire arrays.

    PubMed

    Zhang, Genqiang; Lu, Xiaoli; Zhang, Tao; Qu, Jifeng; Wang, Wei; Li, Xiaoguang; Yu, Shuhong

    2006-08-28

    In order to explore the fundamental properties of one-dimensional nanostructured high-temperature superconductors and enhance their promising applications, a universal and general method for the synthesis of high-quality YBa(2)Cu(3)O(7-δ) (YBCO) nanowire arrays is developed, which involves the combination of a novel sol-gel process to lower the crystallization temperature of YBCO, and porous anodic alumina (PAA) as an effective morphology-directing hard template. Field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) results indicate that the as-prepared YBCO nanowires have average diameters of about 50 nm and lengths up to several microns. The structures of the samples were analysed by x-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), energy-dispersive x-ray spectroscopy (EDX) and inductively coupled plasma (ICP) analysis, which indicate that the nanowires are well crystallized with orthorhombic YBCO-123 structure. The magnetization measurement under zero-field-cooled (ZFC) mode indicates that the superconducting transition temperature (T(c)) of the nanowires is about 92 K, which is in agreement with that of a bulk YBCO sample. PMID:21727567

  11. 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. PMID:25470220

  12. Preparation of orthorhombic Ba sub 2 YCu sub 3 O sub 7 powder by single-step calcining

    SciTech Connect

    Spann, J.R.; Kahn, M. ); Lloyd, I.K. . Engineering Materials Group); Chase, M.T. )

    1990-02-01

    A single calcination step, solid-state process that provides orthohombic Ba{sub 2}YCu{sub 3}O{sub 7} powder is described. BaCO{sub 3}, Y{sub 2}O{sub 3}, and CuO are used as precursor materials. The only phase identifiable by x-ray diffraction is the orthorhombic Ba{sub 2}YCu{sub 3}O{sub 7}. The use of a vacuum during the initial stages of the calcining process promotes complete decomposition of the carbonate, and no residual carbonate is observed. An oxygen atmosphere during the later stages of calcining ensures proper oxidation to Ba{sub 2}YCu{sub 3}O{sub 7}. The use of a similar combination vacuum-oxygen calcining schedule should also be beneficial in the preparation of chemically derived powders.

  13. 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...

  14. Crystal growth and mechanical hardness of In2Se2.7Sb0.3 single crystal

    NASA Astrophysics Data System (ADS)

    Patel, Piyush; Vyas, S. M.; Patel, Vimal; Pavagadhi, Himanshu; Solanki, Mitesh; Jani, Maunik P.

    2015-08-01

    The III-VI compound semiconductors is important for the fabrication of ionizing radiation detectors, solid-state electrodes, and photosensitive heterostructures, solar cell and ionic batteries. In this paper, In2Se2.7 Sb0.3 single crystals were grown by the Bridgman method with temperature gradient of 60 °C/cm and the growth velocity 0.5cm/hr. The as-grown crystals were examined under the optical microscope for surface study, a various growth features observed on top free surface of the single crystal which is predominant of layers growth mechanism. The lattice parameters of as-grown crystal was determined by the XRD analysis. A Vickers' projection microscope were used for the study of microhardness on the as-cleaved, cold-worked and annealed samples of the crystals, the results were discussed, and reported in detail.

  15. Development of YBa2Cu3O7-Ba2YTaO6 nanocomposites by chemical solution deposition

    NASA Astrophysics Data System (ADS)

    Garcés, P.; Coll, M.; Castro, H.; Puig, T.; Obradors, X.

    2014-12-01

    In this work we report the study of chemical solution deposited (CSD) YBa2Cu3O7-δ (YBCO) nanocomposite thin films, with diluted Ba2YTaO6 (BYTO) nanoparticles. We studied the influence of thermal treatment on the properties of nanocomposites, with different content of secondary phases (6%, 10% and 20%). We measured the film microstructure, nanostrain and the superconducting properties: critical temperature (Tc) and critical current density (Jc). The films were characterized using X-rays diffraction and SQUID inductive measurements. The use of two steps in the thermal treatment allowed to increase the nanostrain up to 0.30% for high nanoparticle loads (20%BYTO), decrease the nanoparticle size down to 15 nm and lead a smoother Jc(H) dependence, compared with the standard (single-step) thermal process and the pristine YBCO films.

  16. Continuing investigation of sweeping Jovian resonances - The 7:3 amd 3:2 resonances with further discussion of the 2:1 resonance

    NASA Technical Reports Server (NTRS)

    Torbett, M. V.; Smoluchowski, R.

    1983-01-01

    The formation of the solar system from an accretion disk around the protosun can have a significant impact on the celestial mechanics of the early solar system. The solids in the disk settled to the midplane and formed a planetesimal swarm while an early-formed Jupiter was present. The gravity of the disk makes the radial force law become non-Keplerian, causing the commensurability resonances of the early-formed Jupiter to be displaced from where they would otherwise be. An analysis similar to that previously applied to the 2:1, 3:1 and 5:2 resonances is presently undertaken for the 7:3 and 3:2 resonances, and a Kirkwood-like gap is obtained for a sweeping 7:3 resonance. An accumulation of objects is obtained near the 3:2 resonance which, with the ejection of objects on either side of the resonance, would resemble the Hilda group of asteroids. Agreement between the exact commensurability location and the gap center is discussed for the 2:1 resonance.

  17. Neutrophil P2X7 receptors mediate NLRP3 inflammasome-dependent IL-1β secretion in response to ATP

    PubMed Central

    Karmakar, Mausita; Katsnelson, Michael A.; Dubyak, George R.; Pearlman, Eric

    2016-01-01

    Although extracellular ATP is abundant at sites of inflammation, its role in activating inflammasome signalling in neutrophils is not well characterized. In the current study, we demonstrate that human and murine neutrophils express functional cell-surface P2X7R, which leads to ATP-induced loss of intracellular K+, NLRP3 inflammasome activation and IL-1β secretion. ATP-induced P2X7R activation caused a sustained increase in intracellular [Ca2+], which is indicative of P2X7R channel opening. Although there are multiple polymorphic variants of P2X7R, we found that neutrophils from multiple donors express P2X7R, but with differential efficacies in ATP-induced increase in cytosolic [Ca2+]. Neutrophils were also the predominant P2X7R-expressing cells during Streptococcus pneumoniae corneal infection, and P2X7R was required for bacterial clearance. Given the ubiquitous presence of neutrophils and extracellular ATP in multiple inflammatory conditions, ATP-induced P2X7R activation and IL-1β secretion by neutrophils likely has a significant, wide ranging clinical impact. PMID:26877061

  18. 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.

  19. Co-deposited thin films of YBa 2Cu 3O 7-δ-Ag

    NASA Astrophysics Data System (ADS)

    Moshfegh, A. Z.; Wang, Y. Q.; Sun, Y. Y.; Mesarwi, A.; Hor, P. H.; Ignatiev, A.

    1993-12-01

    The fabrication of high-temperature superconducting YBa 2Cu 3O 7-δ-Ag thin films has been investigated using a high-pressure Ag coevaporation-DC sputtering technique. Various analytical techniques including X-ray diffraction (XRD), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), electron probe microanalysis (EPMA), energy dispersive X-ray analysis (EDX), and Tc measurement have been utilized for characterization of the films. Highly reproducible c-oriented (00 l) films have been prepared in-situ at a relatively low growth temperature (≃670°C) by this technique. The transition temperatures Tc gradually decreased with added Ag from 90 K (0 at.% Ag) to 72 K (22.3 at.% Ag) for the films deposited on MgO (100) substrates. X-ray diffraction indicated that the Ag is in the metallic state as a separate phase with respect to the YBCO and that the c-lattice parameter of the grown films remained unchanged with Ag addition. Surface morphology of the YBCO-Ag films exhibited a particulate-type structure with the grain size increasing as the Ag content increased. The temperature coefficient of the normalized resistance, d R( T)/ R(280 K)/d T, was also noticed to decrease for the Ag- containing samples as compared to Ag-free YBCO films. AES depth profiling identified Ag residing mainly at the YBCO/MgO interface. The effect of Ag addition to the films has been described by a particle growth model.

  20. 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.

  1. Growth, spectroscopic properties and laser performance near 2 μM of Tm3+/Ho3+: SrGdGa3O7 crystal

    NASA Astrophysics Data System (ADS)

    Xia, Houping; Feng, Jianghe; Xu, Jinlong; You, Zhenyu; Wang, Yan; Tu, Chaoyang

    2015-04-01

    The Tm3+/Ho3+: SrGdGa3O7 single crystal was grown by the Czochralski method. The polarized absorption spectra, emission spectra and fluorescence decay curves of the crystal were measured. The crystal exhibited a broad absorption band and a broad emission band, as well as a fluorescence lifetime of 5I7 multiplet of Ho3+ ions up to 8.0 ms. End-pumped by a fiber-coupled diode laser at 808 nm, the laser operation around 2.0 μm has been realized with the a-cut and c-cut crystal samples. The maximum output power is 200 mW when a-cut crystal sample was employed.

  2. Photoluminescence of Tb 3+ and Mn 2+ activated Ca 8MgGd(PO 4) 7 under vacuum ultraviolet excitation

    NASA Astrophysics Data System (ADS)

    Zhang, Jia; Wang, Yuhua; Huang, Yan

    2011-06-01

    Novel Tb 3+ and Mn 2+ activated Ca 8MgGd(PO 4) 7 phosphors were synthesized by solid-state reaction and their photoluminescence properties in vacuum ultraviolet region were investigated for the first time. It can be observed from the excitation spectra that the host-related absorption band is located around 170 nm, and it overlaps the O 2- → Tb 3+ charge transfer band of Ca 8MgGd(PO 4) 7:Tb 3+ around 161 nm and the 3d 5 → 3d 44s transition band of Ca 8MgGd(PO 4) 7:Mn 2+ near 200 nm. The 4f-4f 5d spin-allowed and spin-forbidden transitions of Tb 3+ are verified to be located at 170-250 and 257-271 nm, respectively. Upon 147 nm excitation, the dominant emission peak intensity of the Ca 8MgGd 0.1(PO 4) 7:0.9Tb 3+ phosphor is about 2.7 times stronger than that of the commercial Zn 2SiO 4:Mn 2+ green phosphor, and the brightness of the former with a short decay time of 2.5 ms is about 98% of the latter's. The Ca 8MgGd(PO 4):Mn 2+ phosphor excited at 147 nm exhibits a deep red emission around 650 nm, which could be attributed to the 4T 1 → 6A 1 transition of Mn 2+, with the CIE index (0.679, 0.321). In a word, the results above indicate that both Tb 3+ and Mn 2+ activated Ca 8MgGd(PO 4) 7 phosphors could be promising for PDP or Hg-free lamp applications.

  3. 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.

  4. 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.

  5. 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

  6. Photoluminescence of Au - formed in 12CaO · 7Al 2O 3 single crystal by Au +-implantation

    NASA Astrophysics Data System (ADS)

    Miyakawa, M.; Kamioka, H.; Hirano, M.; Kamiya, T.; Hosono, H.

    2006-09-01

    Au + ion implantation with fluences from 1 × 10 14 to 3 × 10 16 cm -2 into 12CaO · 7Al 2O 3 (C12A7) single crystals was carried out at a sample temperature of 600 °C. The implanted sample with the fluence of 1 × 10 15 cm -2 exhibited photoluminescence (PL) bands peaking at ˜3.1 and ˜2.3 eV at ⩽150 K when excited by He-Cd laser (325 nm). This was the first observation of PL from C12A7. These two PL bands are possibly due to intra-ionic transitions of an Au - ion having the electronic configuration of 6 s2, judged from their similarities to those reported on Au - ions in alkali halides. However, when the concentration of the implanted Au ions exceeded the theoretical maximum value of anions encaged in C12A72.3 × 10 21 cm -3), surface plasmon absorption appeared in the optical absorption spectrum, suggesting Au colloids were formed at such high fluences. These observations indicate that negative gold ions are formed in the cages of C12A7 by the Au + implantation if an appropriate fluence is chosen.

  7. Synthesis, structure, and polymorphism of A3LnSi2O7 (A=Na, K; Ln=Sm, Ho, Yb)

    NASA Astrophysics Data System (ADS)

    Latshaw, Allison M.; Yeon, Jeongho; Smith, Mark D.; zur Loye, Hans-Conrad

    2016-03-01

    Four new members of the A3LnSi2O7 family, K3SmSi2O7, Na3HoSi2O7, and two polymorphs of Na3YbSi2O7, are reported. K3SmSi2O7 crystallizes in the hexagonal space group P63/mcm, Na3HoSi2O7 and Na3YbSi2O7 crystallize in the hexagonal space group P63/m, and Na3YbSi2O7 crystallizes in the trigonal space group P31c. The Na3YbSi2O7 composition that crystallizes in P31c is a new structure type. The magnetic properties for the Ho and Yb analogs are reported.

  8. Electrical Grain Boundary Characteristics of Dense Cubic Li 7-3xAlxLa3Zr2O7 (x = 0.05 - 0.3) Prepared by Spark Plasma Sintering

    NASA Astrophysics Data System (ADS)

    Ibbotson, Matthew Gianni Equi

    In an effort to measure the electrical grain boundary characteristics of fully dense (˜99%) cubic Li 7-3xAlxLa3Zr 2O12 (x = 0.05 - 0.3), small grain size samples of 1 - 2mum were made using the Spark Plasma Sintering (SPS) method. The large internal interfacial area of SPS samples increased the grain boundary contribution to the total resistance to separate typically overlapping bulk and grain boundary impedance responses, supporting grain boundary conductivity (sigma GB) measurements. sigmaGBwas on average two orders of magnitude lower than the bulk conductivity (sigmabulk), indicating the grain boundaries of this material are resistive to Li+ transport, despite literature reports of low grain boundary resistance. sigmaGB = 3.8x10-7 +/- 11%, 7.9x10-7 +/- 11%, and 4.8x10-7 +/- 27% S/cm at 250C with corresponding EaGB = 0.44 +/- 3%, 0.49 +/- 4%, 0.46 +/- 2% eV, for 5, 20, and 30mol%Al 3+ LLZO, respectively. The electrical grain boundary thickness (delta GB) calculated using the Brick Layer Model decreased monotonically with aluminum concentration (CAl3+) to indicate a possible space-charge effect on sigmaGB, and was deltaGB = 10.2 +/- 18% , 9.9 +/- 12% , 6.0 +/- 20% nm for 5, 20, and 30mol%Al LLZO, respectively. Non-linear behavior of sigmaGB with CAl3+ was discussed in terms of competing space-charge and impurity segregation effects that simultaneously influence lithium conduction in the electrical GB. Optimum sigmaGB and sigmabulk of 7.9x10-7 +/- 11% and 4.6x10-4 +/- 4% S/cm at 250C, respectively, were found to coincide at CAl3+ = 20mol%, the critical aluminum dopant concentration for cubic LLZO phase stability.

  9. 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.

  10. 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.

  11. 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...

  12. 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...

  13. Activation of P2X7 receptors in glial satellite cells reduces pain through downregulation of P2X3 receptors in nociceptive neurons

    PubMed Central

    Chen, Yong; Zhang, Xiaofei; Wang, Congying; Li, GuangWen; Gu, Yanping; Huang, Li-Yen Mae

    2008-01-01

    Purinergic ionotropic P2X7 receptors (P2X7Rs) are closely associated with excitotoxicity and nociception. Inhibition of P2X7R activation has been considered as a potentially useful strategy to improve recovery from spinal cord injury and reduce inflammatory damage to trauma. The physiological functions of P2X7Rs, however, are poorly understood, even though such information is essential for making the P2X7R an effective therapeutic target. We show here that P2X7Rs in satellite cells of dorsal root ganglia tonically inhibit the expression of P2X3Rs in neurons. Reducing P2X7R expression using siRNA or blocking P2X7R activity by antagonists elicits P2X3R up-regulation, increases the activity of sensory neurons responding to painful stimuli, and evokes abnormal nociceptive behaviors in rats. Thus, contrary to the notion that P2X7R activation is cytotoxic, P2X7Rs in satellite cells play a crucial role in maintaining proper P2X3R expression in dorsal root ganglia. Studying the mechanism underlying the P2X7R–P2X3R control, we demonstrate that activation of P2X7Rs evokes ATP release from satellite cells. ATP in turn stimulates P2Y1 receptors in neurons. P2Y1 receptor activation appears to be necessary and sufficient for the inhibitory control of P2X3R expression. We further determine the roles of the P2X7R–P2Y1–P2X3R inhibitory control under injurious conditions. Activation of the inhibitory control effectively prevents the development of allodynia and increases the potency of systemically administered P2X7R agonists in inflamed rats. Thus, direct blocking P2X7Rs, as proposed before, may not be the best strategy for reducing pain or lessening neuronal degeneration because it also disrupts the protective function of P2X7Rs. PMID:18946042

  14. 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......

  15. Design, synthesis, and evaluation of 7H-thiazolo-[3,2-b]-1,2,4-triazin-7-one derivatives as dual binding site acetylcholinesterase inhibitors.

    PubMed

    Liu, Sijie; Shang, Ruofeng; Shi, Lanxiang; Zhou, Ran; He, Jingyu; Wan, David Chi-Cheong

    2014-08-01

    New dual binding site acetylcholinesterase (AChE) inhibitors have been designed and synthesized as a new drug candidate for the treatment of Alzheimer's disease (AD) through the binding to both catalytic and peripheral sites of the enzyme. Therefore, a series of 7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives 6a-j were synthesized and investigated for their ability to inhibit the activity of human AChE (hAChE) in comparison with huperzine-A. All the compounds were found to inhibit AChE activity, especially compounds 6c and 6i with the inhibition value of 76.10% and 77.82%, respectively. The molecular docking study indicated that they were nicely accommodated by AChE. The molecular docking study revealed that 6c and 6i possessed a more optimal binding conformation than 6a and can perfectly fit into the active and peripheral site of hAChE, and consequently exhibited highly improved inhibitor potency to hAChE. PMID:24890706

  16. 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. PMID:25529477

  17. 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.

  18. Synthesis, characterization, and crystal structure of 2-amino-7-methyl-5-oxo-4-phenyl-4,5-dihydropyrano[3,2- c]pyran-3-carbonitrile

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    2-Amino-7-methyl-5-oxo-4-phenyl-4,5-dihydropyrano[3,2- c]pyran-3-carbonitrile, C16H12N2O3 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. P21/ 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.

  19. 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

  20. 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.

  1. Growth of 3-Inch-Diameter Li2B4O7 Single Crystal Using the Resistance Heating Furnace

    NASA Astrophysics Data System (ADS)

    Sugawara, Tamotsu; Komatsu, Ryuichi; Sugihara, Tadashi

    1994-09-01

    The mode and origin of cracking of lithium tetraborate ( Li2B4O7) single crystals during growth using a resistance heating furnace have been studied. The relationship between the formation mechanism of anomalous growth ridges and the occurrence of cracking was examined. It is concluded that a high temperature gradient near the interface and small temperature fluctuations in the melt are needed for growing a crack-free 3-inch-diameter Li2B4O7 single crystal.

  2. Novel inorganic borate host phosphor K2Al2B2O7:Dy3+ for LED based solid state lighting

    NASA Astrophysics Data System (ADS)

    Palaspagar, R. S.; Sonekar, R. P.; Omanwar, S. K.

    2013-06-01

    In the present work we report the preparation and photoluminescence characteristics of Dy3+ doped borate phosphor K2Al2B2O7:Dy3+. The fine polycrystalline powder samples of K2Al2B2O7:Dy3+ has been prepared by a novel combustion technique. This method is based on the exothermic redox reaction involves, metal nitrates and organic fuel (urea). The formation of samples was confirmed by powder XRD technique. The photoluminescence properties of borate phosphors have been investigated on fluorescence spectrometer (F-7000). The PL excitation spectra of K2Al2B2O7:Dy3+ consists of several bands peaking at 241 nm, 297 nm, 324 nm, 350 nm, 364 nm and 387 nm. Since the prominent excitation peaks are above 360nm, the phosphor may useful for solid state lighting application. The emission spectrum monitored at 351 nm excitation consists of blue emission band peaking at 481 nm and yellow emission band peaking at 574nm.

  3. Magnetic and electrical characterization of YBa 2Cu 3O 7 thin films made by laser ablation

    NASA Astrophysics Data System (ADS)

    Vase, Per; Shen, Yue Quang; Freltoft, Torsten

    1991-09-01

    High quality epitaxial thin films of YBa 2Cu 3O 7 have been deposited on single crystal MgO (100), SrTiO 3 (100), and LaAlO 3 (100) by laser ablation. The transport critical current density at 77 K is in the range of 10 6 - 10 7 A/cm 2 depending on the type of substrate. An alternative way to measure the critical current density based on high probe field ac-susceptibility measurements, avoiding the needs of patterning, is described, and the results are compared to transport measurement.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Fabrication and characterization of long-persistent luminescence/polymer (Ca2MgSi2O7:Eu2+, Dy3+/PLA) composite fibers by electrospinning

    NASA Astrophysics Data System (ADS)

    Ye, Feng; Dong, Shengjie; Tian, Zhe; Yao, Sijia; Zhou, Zhufa; Wang, Shumei

    2015-07-01

    Long-persistent luminescence /polymer (Ca2MgSi2O7:Eu2+, Dy3+/PLA) composite fibers have been fabricated via electrospinning method. The as-prepared one-dimensional fiber has been characterized by fluorescence microscope and distinct photographs have been obtained. The results show that the Ca2MgSi2O7:Eu2+, Dy3+ particles (12 wt%, size 200 nm) are uniformly dispersed in the PLA fibers (diameter 2.5 μm). It was found that the composite fibers have an emission band from 430 nm to 650 nm that peaks at 537 nm and 452 nm. Similarly, its phosphorescent emission spectra have similar features of luminescence (emission band from 430 nm to 650 nm that peaks at 537 nm and 452 nm). The decay curves of the composite fibers present a similar attenuate tendency with Ca2MgSi2O7:Eu2+, Dy3+ pure particles, but with lower intensity. The composite fiber has applications possibility in textile, display, optical detectors, indicator in the dark without electric energy which they never had before.

  10. Design and Synthesis of (2-(5-Chloro-2,2-dimethyl-2,3-dihydrobenzofuran-7-yl)cyclopropyl)methanamine as a Selective Serotonin 2C Agonist

    PubMed Central

    Cheng, Jianjun; Giguere, Patrick M.; Lv, Wei; Roth, Bryan L.; Kozikowski, Alan P.

    2015-01-01

    A conformationally restricted analog of a selective cyclopropane-bearing serotonin 2C agonist was designed and synthesized. A 2,2-dimethyl-2,3-dihydrobenzofuran scaffold was investigated as a constrained variant of a biologically active isopropyl phenyl ether. Construction of the required dimethyl-2,3-dihydrobenzofuran intermediate began using a procedure that relied on a microwave-assisted alkylation reaction. The synthesis of the designed compound as its HCl salt is reported in a total of 12 steps and 17% overall yield. Biological evaluation revealed the constrained analog to be a selective serotonin 2C agonist with modest potency. PMID:26120215

  11. Quantitative analysis of thin films of RBa(2)Cu(3)O(7-x) (R-rare earth elements) and ZrO(2) (Y(2)O(3)) buffer layers by SNMS.

    PubMed

    Rebane, J A; Kaul, A R; Tretyakov, Y D

    1996-12-01

    It is shown that RBa(2)Cu(3)O(7-X) single crystals may be used as reference samples for the quantitative analysis of RBa(2)Cu(3)O(7-X) thin films by SNMS. RSF-values for Y and Cu (relative to Ba) determined for ceramic RBa(2)Cu(3)O(7-X) samples are higher than those for single crystals. This difference may be caused by Ba segregation on grain boundaries. The depth profile analysis of YSZ/Al(2)O(3) samples was performed by DBM using a Ni grid to prevent sample charging. The reproducibility of analysis was better than 10%. PMID:15045213

  12. X-ray absorption spectroscopy study of the electronic and magnetic proximity effects in YBa2Cu3O7/La2 /3Ca1 /3MnO3 and La2 -xSrxCuO4/La2 /3Ca1 /3MnO3 multilayers

    NASA Astrophysics Data System (ADS)

    Uribe-Laverde, M. A.; Das, S.; Sen, K.; Marozau, I.; Perret, E.; Alberca, A.; Heidler, J.; Piamonteze, C.; Merz, M.; Nagel, P.; Schuppler, S.; Munzar, D.; Bernhard, C.

    2014-11-01

    With x-ray absorption spectroscopy we investigated the orbital reconstruction and the induced ferromagnetic moment of the interfacial Cu atoms in YBa2Cu3O7/La2 /3Ca1 /3MnO3 (YBCO/LCMO) and La2 -xSrxCuO4/La2 /3Ca1 /3MnO3 (LSCO/LCMO) multilayers. We demonstrate that these electronic and magnetic proximity effects are coupled and are common to these cuprate/manganite multilayers. Moreover, we show that they are closely linked to a specific interface termination with a direct Cu-O-Mn bond. We furthermore show that the intrinsic hole doping of the cuprate layers and the local strain due to the lattice mismatch between the cuprate and manganite layers are not of primary importance. These findings underline the central role of the covalent bonding at the cuprate/manganite interface in defining the spin-electronic properties.

  13. Structural, electrical and magnetic characterization of artificial ferromagnetic/superconducting (La(0.7)Ca(0.3)MnO(3)/YBa(2)Cu(3)O(7-x)) heterostructures.

    PubMed

    Piano, S; De Santis, A; Bobba, F; Giubileo, F; Longobardi, M; Di Bartolomeo, A; Polichetti, M; Scarfato, A; Zola, D; Vecchione, A; Cucolo, A M

    2009-06-24

    The fabrication and characterization of superconducting and ferromagnetic heterostructures is an open field due to the fundamental interest in the physics of the coexistence of these two competing orders and their possible applications in the spintronics industry. In this paper we present structural, electrical and magnetic characterization for the single La(0.7)Ca(0.3)MnO(3) (LCMO) thin layer, La(0.7)Ca(0.3)MnO(3)/YBa(2)Cu(3)O(7-x) (LCMO/YBCO) bilayers and the LCMO/YBCO/LCMO trilayers. In particular, we show a detailed magnetic characterization of the LCMO thin films by means of low temperature magnetic force microscopy. We discuss the different dynamics of the magnetic domains observed, depending on the substrate induced strain and on the film thickness. PMID:21828429

  14. 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

  15. Investigations on the g factors for the Cu2+ sites in YBa1.9Na0.1Cu3O7-δ and YBa2Cu3O7

    NASA Astrophysics Data System (ADS)

    Chao-Ying, Li; Xue-Mei, Zheng

    2013-03-01

    The anisotropic g factors gi (i=x, y, z ) for the six-fold coordinated orthorhombic Cu2+(1) site in YBa1.9Na0.1Cu3O7-δ and the five-fold coordinated tetragonal Cu2+(2) site in YBa2Cu3O7-δ are theoretically studied from the perturbation formulas of the g factors for a 3d9 ion in orthorhombically and tetragonally elongated octahedra, respectively. The orthorhombic (or tetragonal) field parameters are obtained using the superposition model and the local structures of the Cu2+ sites. In view of covalency, the contributions from the ligand orbital and spin-orbit coupling interactions are taken into account. For the Cu2+(1) site in YBa1.9Na0.1Cu3O7-δ, the axial anisotropy Δg[=gz-(gx-gy)/2] may be ascribed to the moderate (about 3%) elongation of the Cu-O distance along c axis, while the perpendicular anisotropy δg(=gx-gy) can be characterized by the planar bond length deviation difference δR(≈0.083 Å) in the perpendicular (ab) plane. However, for the Cu2+(2) site in YBa2Cu3O7-δ, the anisotropy Δg(=g||-g⊥) is illustrated by the significant elongation of the [CuO5]8- cluster along c axis with about 25% longer axial Cu-O distance than the four planar ones. The theoretical g factors are in good agreement with the experimental data.

  16. 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

  17. 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.

  18. 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.

  19. Flux dynamics and irreversibility in YBa sub 2 Cu sub 3 O sub 7 with Y sub 2 BaCuO sub 5 inclusions and in single crystal YBa sub 2 Cu sub 3 O sub 7

    SciTech Connect

    Fossheim, K.; Karkut, M.G.; Heill, L.K.; Slaski, M.; Sagdahl, L.T. . Div. of Physics Selskapet for Industriell og Teknisk Forskning, Trondheim ); Vinokur, V. ); Murakami, M.; Fujimoto, H.; Koshizuka, N.; Tanaka, S. ); Gencer, F.; Abell, J.S.; Gough, C.E. (School of

    1992-01-01

    We have measured the ac magnetic permeability response function {mu} = {mu}{prime} + i{mu}{double prime} in melt-processed melt grown YBa{sub 2}Cu{sub 3}O{sub 7} with Y{sub 2}BaCuO{sub 5} inclusions (MPMG) and in single crystal YBa{sub 2}Cu{sub 3}O{sub 7} (SC) in applied magnetic fields up to 8 Tesla oriented either parallel or perpendicular to the crystalline c-axis. The ac response of the two samples has been mapped out as a function of temperature, frequency, ac field amplitude, dc applied field, and field orientation. The peak in the lossy part of the susceptibility {mu}{double prime} is used to probe the flux dynamics in the vicinity of the irreversibility line. The data are interpreted by comparison with expectations of an anisotropic vortex glass- to -liquid transition. The inferred melting lines as well as the frequency dependence and non-linear response are in overall agreement with the expected behavior. In the range of available parameters and variables we find the system to be in the solid vortex phase for H{perpendicular}c since there is a strong H{sub ac} dependence and only a weak frequency dependence on the temperature position of the loss peak. For H{parallel}c, the situation is reversed, and the loss peak depends only weakly on H{sub ac} and strongly on the frequency.

  20. Photodissociation dynamics of the 2-propyl radical, C{sub 3}H{sub 7}

    SciTech Connect

    Noller, Bastian; Fischer, Ingo

    2007-04-14

    The photodissociation of 2-propyl leading to propene+H was investigated with nanosecond time resolution. A supersonic beam of isolated 2-propyl radicals was produced by pyrolysis of 2-bromopopane. The kinetic energy release of the H-atom photofragment was monitored as a function of excitation wavelength by photofragment Doppler spectroscopy via the Lyman-{alpha} transition. The loss of hydrogen atoms after excitation proceeds in {alpha} position to the radical center with a rate constant of 5.8x10{sup 7} s{sup -1} at 254 nm. Approximately 20% of the excess energy is deposited as translation in the H-atom photofragment. In contrast 1-propyl does not lose H atoms to a significant extent. The experimental results are compared to simple Rice-Ramsperger-Kassel-Marcus calculations. The possible reaction pathways are examined in hybrid density functional theory calculations.

  1. 2-Amino-4-methyl-4,5,6,7-tetrahydro-1-benzothiophene-3-carbonitrile.

    PubMed

    Khan, Ashraf Y; Fathima, Nikhath; Kalashetti, Mallikarjun B; Begum, Noor Shahina; Khazi, I M

    2012-10-01

    In the title compound, C(10)H(12)N(2)S, the thio-phene ring is essentially planar (r.m.s. deviation = 0.0290 Å). The two C atoms of the cyclo-hexene ring (at positions 6 and 7) are disordered over two sets of sites in a 0.810 (5):0.190 (5) ratio. The cyclo-hexene rings in both the major and minor occupancy conformers adopt a half-chair conformation. In the crystal, there are two types of N-H⋯N inter-action. One of these results in centrosymmetric head-to-head dimers corresponding to an R(2) (2)(12) graph-set motif and the other forms a 20-membered macrocyclic ring involving six mol-ecules. PMID:23125792

  2. Piezo-strain induced non-volatile resistance states in (011)-La2/3Sr1/3MnO3/0.7Pb(Mg2/3Nb1/3)O3-0.3PbTiO3 epitaxial heterostructures

    NASA Astrophysics Data System (ADS)

    Yang, Yuanjun; Luo, Z. L.; Meng Yang, Meng; Huang, Haoliang; Wang, Haibo; Bao, J.; Pan, Guoqiang; Gao, C.; Hao, Qiang; Wang, Shutong; Jokubaitis, Michael; Zhang, Wenzhe; Xiao, Gang; Yao, Yiping; Liu, Yukuai; Li, X. G.

    2013-01-01

    The non-volatile resistance states induced by converse piezoelectric effect are observed in ferromagnetic/ferroelectric epitaxial heterostructures of (011)-La2/3Sr1/3MnO3/0.7Pb(Mg2/3Nb1/3)O3-0.3PbTiO3 (LSMO/PMN0.7PT0.3). Three stable remnant strain states and the corresponding resistance states are achieved by properly reversing the electric field from the depolarized direction in ferroelectric PMN0.7PT0.3 substrate. The non-volatile resistance states of the LSMO film can be manipulated by applied electric-field pulse sequence as a result of the large coupling between the electronic states of LSMO film and the strain transferred from the ferroelectric substrate. The electrically tunable, non-volatile resistance states observed exhibit potential for applications in low-power-consumption electronic devices.

  3. A physiologically-based pharmacokinetic model for disposition of 2,3,7,8-TCDD in fathead minnow and medaka.

    PubMed

    Parhizgari, Zahra; Li, James

    2014-05-01

    A physiologically-based pharmacokinetic model was developed for the disposition of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in 2 fish species--fathead minnow and medaka. The model was developed based on the empirical data on disposition of dioxins in fish tissues, as well as existing knowledge on the mechanisms of uptake, distribution, storage, and elimination of dioxins in various species (other than fish). The present study examined the applicability of mechanisms known to occur in other species for fish and concluded that the same mechanisms defined for disposition of 2,3,7,8-TCDD in (mostly) rodents can be applicable for the 2 fish species examined as well. Parameter values for the model were selected and/or calibrated using available databases. Model compartments included the gill, kidney, liver, and other richly-perfused tissues, as well as fat and other slowly-perfused tissues. The model was calibrated using 2 independent datasets for exposure of fathead minnow and medaka to 2,3,7,8-TCDD in water. The initial values of the model parameters were selected from several sources, and calibrated to represent the 2 exposure datasets. With very few exceptions, the estimated parameter values for the 2 species were comparable, and the final predictions were in strong agreement with the observations. The model developed in the present study can therefore be used in the prediction of the body burden of 2,3,7,8-TCDD in fathead minnow and medaka. Uncertainty in the model prediction as a result of variability in input parameters is discussed for the parameters with the highest impacts on the model outcome. PMID:24375498

  4. Insert coil test for HEP high field magnets using yba2cu3o7-δ coated conductor tapes

    NASA Astrophysics Data System (ADS)

    Lombardo, Vito; Barzi, Emanuela; Turrioni, Daniele; Zlobin, Alexander

    2012-06-01

    The final beam cooling stages of a Muon Collider require DC solenoid magnets with magnetic fields of 30-50 T. In this paper we present progress in insert coil development using commercially available YBa2Cu3O7.δ Coated Conductor. Technological aspects covered in the development, including coil geometry, insulation, manufacturing process and testing are summarized and discussed. Test results of double pancake coils operated in liquid nitrogen and liquid helium are presented and compared with the performance of YBa2Cu3O7.δ tape short samples.

  5. 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.

  6. Selective interlayer ferromagnetic coupling between the Cu spins in YBa2Cu3O7–x grown on top of La0.7Ca0.3MnO3

    DOE PAGESBeta

    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

  7. 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

  8. Selective interlayer ferromagnetic coupling between the Cu spins in YBa2Cu3O7-x grown on top of La0.7Ca0.3MnO3.

    PubMed

    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

  9. CHAPTER 7: EPIDEMIOLOGY/HUMAN DATA - HEALTH ASSESSMENT FOR 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD) AND RELATED COMPOUNDS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) is conducting a scientific reassessment of the risks of exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and chemically similar compounds collectively known as dioxin. PA has undertaken this task in response to emerging scienti...

  10. Design, Preparation, and Characterization of a Novel Red Long-Persistent Perovskite Phosphor: Ca3Ti2O7:Pr3+.

    PubMed

    Wang, Bo; Lin, Hang; Xu, Ju; Chen, Hui; Lin, Zebin; Huang, Feng; Wang, Yuansheng

    2015-12-01

    Currently, the development of efficient red-emitting persistent phosphor is still an ongoing challenge. Herein, a novel red-emitting LPL phosphor Ca3Ti2O7:Pr(3+) is successfully prepared by a high-temperature solid-state method. XRD Rietveld refinement analyses demonstrate the high phase purity of the sample which crystallizes in an orthorhombic Ccm21 space group with lattice parameters of a = 5.7702(5) Å, b = 19.4829(7) Å, and c = 5.1214(2) Å. Electronic structure of the host matrix is analyzed by the first-principle calculation using CASTEP code. The calculation results show that Ca3Ti2O7 has a direct band gap with CB and VB mainly composed of the Ti-3d and O-2p states, respectively. On the basis of the DR spectrum, the band gap is determined to be 3.6 eV. It is demonstrated that the 612 nm red-emitting persistent luminescence of Ca3Ti2O7:Pr(3+) can be either activated by Ti(4+)-O(2-) → Ti(3+)-O(-) host absorption and Pr(3+)-O-Ti(4+) → Pr(4+)-O-Ti(3+) IVCT in the UV region, or Pr(3+):(3)H4 → (3)PJ transition in the blue region. The red afterglow can last for ∼ 5 min observed by the naked eyes in the dark after ceasing the irradiation source. On the basis of the TL analyses, the trap is found exponentially distributed in the host with the depth of 0.69-0.92 eV. Finally, a possible LPL mechanism for Ca3Ti2O7:Pr(3+) is proposed. PMID:26561233

  11. 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.

  12. Mechanism and kinetics study on the ozonolysis reaction of 2,3,7,8-TCDD in the atmosphere.

    PubMed

    Bai, Jing; Sun, Xiaomin; Zhang, Chenxi; Gong, Chen; Hu, Jingtian; Zhang, Jianghua

    2014-01-01

    The ozonolysis of 2,3,7,8-tetra-chlorodibenzo-p-dioxin (2,3,7,8-TCDD) is an efficient degradation way in the atmosphere. The ozonolysis process and possible reactions path of Criegee Intermediates with NO and H2O are introduced in detail at the method of MPWB1K/6-31+G(d,p)//MPWB1K/6-311+G(3df,2p) level. In ozonolysis, H2O is an important source of OH radical formation and initiated the subsequent degradation reaction. The Rice-Ramsperger-Kassel-Marcus (RRKM) theory was applied to calculate rate constants with the temperature ranging from 200 to 600 K. The rate constant of reaction between 2,3,7,8-TCDD and O3 is 4.80 x 10(-20) cm3/(mole x sec) at 298 K and 760 Torr. The atmospheric lifetime of the reaction species was estimated according to rate constants, which is helpful for the atmospheric model study on the degradation and risk assessment of dioxin. PMID:24649705

  13. Structural and ferroelectric properties of BaTiO 3/YBa 2Cu 3O 7 heterostructures prepared by laser molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Wang, H. S.; Liu, Y. W.; Ma, K.; Peng, Z. Q.; Cui, D. F.; Lu, H. B.; Zhou, Y. L.; Chen, Z. H.; Li, L.; Yang, G. Z.

    1997-08-01

    Heteroepitaxial BaTiO 3(BTO)/YBa 2Cu 3O 7(YBCO) thin films were grown on (100) SrTiO 3(STO) substrates by ozone assistant laser molecular beam epitaxy (L sbnd MBE). The results show that by using this technique, high quality ferroelectric/superconductor heterostructures with high crystalline quality and desirable device performance can be obtained.

  14. 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.

  15. 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.

  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. 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.

  18. Intense 2.7 μm and broadband 2.0 μm emission from diode-pumped Er3+/Tm3+/Ho(3+)-doped fluorophosphate glass.

    PubMed

    Tian, Ying; Xu, Rongrong; Hu, Lili; Zhang, Junjie

    2011-08-15

    This Letter reports intense emission at 2.7 μm and broadband emission at 2.0 μm from Er(3+)/Tm(3+)/Ho(3+)-doped fluorophosphate glass. The fluorescence characteristics and energy transfer upon excitation of a conventional 980 nm laser diode are investigated. Based on the fluorescence spectra and lifetime measurement, the effect of Tm(3+) and Ho(3+) ions on intense 2.7 μm emission in fluorophosphate glass is demonstrated. It is also found that the effective bandwidth of 2.0 μm emission due to Tm(3+) and Ho(3+) ions can reach as high as 196 nm. These results indicate that the advantageous spectroscopic characteristics of Er(3+)/Tm(3+)/Ho(3+) triply doped fluorophosphate glass together with the outstanding thermal properties may become an attractive host for the mid-IR solid state lasers. PMID:21847213

  19. Mechanisms of oxygen ion diffusion in a nanoporous complex oxide 12CaO•7 Al2 O3

    NASA Astrophysics Data System (ADS)

    Sushko, Peter V.; Shluger, Alexander L.; Hayashi, Katsuro; Hirano, Masahiro; Hosono, Hideo

    2006-01-01

    We performed a theoretical analysis of O2- diffusion mechanisms in a nanoporous complex oxide 12CaO•7Al2O3 (C12A7). This material can be viewed as a positively charged framework, arranged in subnanometer sized cages, hosting extra-framework O2- ions occupying one in six cages. Using both classical molecular-dynamics simulations and ab initio calculations we demonstrate that the diffusion of O2- species is dominated by the exchange of framework and extra-framework O2- ions rather than by an interstitial diffusion mechanism. The results allow us to rationalize the origins of the experimentally observed high oxide ion conductivity of C12A7 and the stability of its lattice under positive ion-beam irradiation.

  20. Benzene-1,2,4,5-tetra-carb-oxy-lic acid bis-(1,3,7-trimethyl-2,3,6,7-tetra-hydro-1H-purine-2,6-dione).

    PubMed

    Arman, Hadi D; Tiekink, Edward R T

    2013-01-01

    The asymmetric unit of the title co-crystal, C10H6O8·2C8H10N4O2, comprises a centrosymmetric benzene-1,2,4,5-tetra-carb-oxy-lic acid (LH4) mol-ecule and a mol-ecule of caffeine in a general position. LH4 is nonplanar, with the dihedral angles between the ring and pendent carb-oxy-lic acid groups being 44.22 (7) and 49.74 (7)°. By contrast, the caffeine mol-ecule is planar (r.m.s. deviation = 0.040 Å). Supra-molecular layers parallel to (-1-10) are sustained by carb-oxy-lic acid O-H⋯O(carbon-yl) and O-H⋯N(imidazole) hydrogen bonds, as well as by meth-yl-carbonyl C-H⋯O inter-actions. These stack via π-π inter-actions between the benzene and imidazole rings [inter-centroid distance = 3.4503 (10) Å]. PMID:24427071

  1. 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.

  2. An Alternating Copolymer Derived from Indolo[3,2-b]carbazole and 4,7-Di(thieno[3,2-b]thien-2-yl)-2,1,3-benzothiadiazole for Photovoltaic Cells.

    PubMed

    Xia, Yangjun; Su, Xuehua; He, Zhicai; Ren, Xia; Wu, Hongbing; Cao, Yong; Fan, Duowang

    2010-07-15

    An alternating narrow bandgap conjugated copolymer (PICZ-DTBT, E(g)  = 1.83 eV) derived from 5,11-di(9-heptadecanyl)indolo[3,2-b]carbazole and 4,7-di(thieno[3,2-b]thien-2-yl)-2,1,3-benzothiadiazole (DTBT), was prepared by the palladium-catalyzed Suzuki coupling reaction. The resultant polymer absorbs light from 350-690 nm, exhibits two absorbance peaks at around 420 and 570 nm and has good solution processibility and thermal stability. The highest occupied molecular orbital (HOMO) energy level and lowest unoccupied molecular orbital (LUMO) level of the copolymer determined by cyclic voltammetry were about -5.18 and -3.35 eV, respectively. Prototype bulk heterojunction photovoltaic cells from solid-state composite films based on PICZ-DTBT and [6,6]-phenyl-C(71) butyric acid methyl ester (PC(71) BM), show power conversion efficiencies up to 2.4% under 80 mW · cm(-2) illumination (AM1.5) with an open-circuit voltage of V(oc)  = 0.75 V, a short current density of J(sc)  = 6.02 mA · cm(-2) , and a fill factor of 42%. This indicates that the copolymer PICZ-DTBT is a viable electron donor material for polymeric solar cells. PMID:21567526

  3. Bis(μ 3-iodo)-pentakis(μ 2-iodo)-penta-copper(I) - A fully ordered, isolated [Cu 5I 7] 2- cluster

    NASA Astrophysics Data System (ADS)

    Jalilian, Ehsan; Lidin, Sven

    2011-04-01

    Two new compounds, [(C 4H 9) 4P] 2[Cu 5I 7] and [(C 4H 9) 4P] 2[Cu 5I 7]·CH 3COCH 2OH were synthesized by solvolysis and their crystal structures were solved. The first compound is disordered, but the solvate represents the first example of a fully ordered [Cu 5I 7] 2- cluster. It displays a molecular symmetry very close to C 2. Both compounds crystallize in space group P2 1/c.

  4. The microwave spectrum, structure and dipole moment of cyclobutene ozonide (2,3,7-trioxabicyclo[2.2.1]heptane)

    NASA Astrophysics Data System (ADS)

    Borseth, Donald G.; Lorenčak, Primož; Badawi, Hassan M.; Hillig, Kurt W.; Kuczkowski, R. L.; Mendenhall, G. David

    1988-11-01

    Cyclobutene ozonide containing deuterium, 13C and 18O enrichment was prepared by ozonolysis of cyclobutene and via singlet molecular oxygen addition to furan. It was established that the ozonide has Cs symmetry. The structure was determined from the assignment of the microwave spectra of eight isotopic species. The peroxy bond distance of 1.492(5) Å is increased by about 0.03 Å compared with less strained monocyclic ozonides. The ring strain is also evident in several other bond distances and angles when compared with cyclopentene ozonide. The dipole moment is 2.857(2) debye.

  5. 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.

  6. 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 Central

    Hooth, Michelle J.; Nyska, Abraham; Fomby, Laurene M.; Vasconcelos, Daphne Y.; Vallant, Molly; DeVito, Michael J.; Walker, Nigel J.

    2012-01-01

    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, 50000 and 500000 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. PMID:22813907

  7. MUTAGENICITY AND CLASTOGENICITY OF ADRIAMYCIN IN L5178Y/TK+/- 3.7.2C MOUSE LYMPHOMA CELLS

    EPA Science Inventory

    Adriamycin was a potent mutagen at the tk locus of L5178Y/TK+/- -3.7.2C mouse lymphoma cells. A dose of 5 ng/ml gave total mutant frequencies of 417/ten to the 6th power survivors (background = 110/ten to the 6th power; survival = 62%) and 350/ten to the 6th power survivors (back...

  8. 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...

  9. High Temperature Superconductor GdBa2Cu3O7-x Investigation by Optically Thermostimulated Exoemission (otsee) Method

    NASA Astrophysics Data System (ADS)

    Chrzanowski, J.; Sujak, B.; Benzar, I.; Zaleski, A. J.; Ciszek, M.; Olejniczak, J.

    Measurements of optically-thermostimulated electron emission from the high temperature superconductor GdBa2Cu3O7-x were performed for the temperature range of 65-300 K. Changes in the intensity of the emitted electrons with temperature were observed. OTSEE peak at about 230 K is ascribed to structural changes in the sample, which are reflected at surface layer.

  10. SORPTION OF 2, 3, 7, 8-TETRACHLORODIBENZO-P-DIOXIN TO SOILS FROM WATER/METHANOL MIXTURES

    EPA Science Inventory

    Sorption of 14 C-labeled 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCCD) to Soils from water/methanol mixtures has been evaluated by batch shake testing. ncontaminated soils from Times Beach, MO, were used in these experiments and ranged in fraction organic carbon (foc) from 0.0066 to...

  11. EFFECTS OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD) ON FETAL MOUSE URINARY TRACT EPITHELIUM IN VITRO

    EPA Science Inventory

    2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), produces hydronephrosis by altering the differentiation and proliferation of ureteric epithelial cells in the embryonic C57BL/6N mouse urinary tract. This study examines the effects of TCDD on late gestation fetal urinary tract cells u...

  12. 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

  13. Crossover point in the magnetic phase diagram of YBa2Cu3O7-δ with twin planes

    NASA Astrophysics Data System (ADS)

    Morgoon, V. N.; Bindilatti, V.; Bondarenko, A. V.; Rodrigues, D.; Sivakov, A. V.

    1996-03-01

    We studied the vortex melting transition in twinned YBa2Cu3O7-δ single crystals and observed the critical point where the continuous vortex-glass line joins the first order melting line, and pinning in liquid-vortex state.

  14. 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...

  15. 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…

  16. 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

  17. 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

  18. 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.

  19. Thermal expansion of the high-7c superconductors REBa2Cu3O7 (RE = Y, Dy) revisited at low temperatures

    NASA Astrophysics Data System (ADS)

    Lahoubi, M.

    2014-05-01

    The linear thermal expansion coefficient α(T) of two high-Tc superconductors, YBa2Cu3O7 and DyBa2Cu3O7 has been revisited in the 4.5-80K temperature range. The X-ray diffraction analysis and microstructural characterization using scanning electron microscopy confirm an orthorhombic single phase with an average of the grain size of about 20 μm for both polycrystalline samples. In the case of the Dy compound, a small magnetic excess superimposed to the high phonon contribution is observed in the T3 term, whereas no anomaly is detected below 40K. The deduced magnetic contribution αm(T) which increases monotonically with rising temperature is attributed to the CF interactions induced by the 4f electric quadrupole moment of the Dy Kramers ions. A discussion and a comparison with respect to the previous experimental and theoretical works are presented.

  20. Excellent performances of energy harvester using cantilever driving double-clamped 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 plates and symmetric middle-stops

    NASA Astrophysics Data System (ADS)

    Zeng, Zhou; Ren, Bo; Xu, Qing; Lin, Di; Di, Wenning; Luo, Haosu; Wang, Dong

    2015-10-01

    We present a high performance nonlinear piezoelectric energy harvester constituted by a cantilever with symmetrically middle-stops and double-clamped piezoelectric plates based on piezoelectric single crystal 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3. Electrical properties of the device under different excitation frequencies, accelerations, and load resistances are studied systematically. Under a low acceleration of 3 m/s2 (0.3 g), a peak voltage of 26.2 V and a maximum normalized power of 25.6 mW/g2 were obtained across a matching impedance of 600 kΩ with favorable bandwidths. The low excitation acceleration and excellent performances indicate that the device can be a promising candidate for energy harvesting in low-power electronics and wireless sensors.

  1. 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.

  2. 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.

  3. Synthesis and structural/physical properties of U3Fe2Ge7: a single-crystal study.

    PubMed

    Henriques, Margarida S; Gorbunov, Denis I; Waerenborgh, João C; Pasturel, Mathieu; Andreev, Alexander V; Dušek, Michal; Skourski, Yurii; Havela, Ladislav; Gonçalves, António P

    2015-10-01

    A single crystal of U3Fe2Ge7 was synthesized by the tin-flux method, and its structural and electronic properties were studied. The compound crystallizes in the orthorhombic crystal structure of La3Co2Sn7 type with two Wyckoff sites for the U atoms. U3Fe2Ge7 displays a ferromagnetic order below TC = 62 K. Magnetization measurements in static (up to 14 T) and pulsed (up to 60 T) magnetic fields revealed a strong two-ion uniaxial magnetic anisotropy. The easy magnetization direction is along the c axis and the spontaneous magnetic moment is 3.3 μB per formula unit at 2 K. The moment per Fe atom is 0.2 μB, as follows from Mössbauer spectroscopy. The magnetic moments are oriented perpendicular to the shortest inter-uranium distances that occur within the zigzag chains in the ab plane, contrary to other U-based isostructural compounds. The magnetization along the a axis reveals a first-order magnetization process that allows for a quantitative description of the magnetic anisotropy in spite of its enormous energetic strength. The strong anisotropy is reflected in the specific heat and electrical resistivity that are affected by a gap in magnon spectrum. PMID:26371628

  4. 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.

  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. 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.

  7. Novel configuration of processing bulk textured YB 2Cu 3O 7-x superconductor by seeded infiltration growth method

    NASA Astrophysics Data System (ADS)

    Cao, Haitao; Moutalbi, Nahed; Harnois, Christelle; Hu, Rui; Li, Jinshan; Zhou, Lian; Noudem, Jacques G.

    2010-01-01

    Mono-domain YBa 2Cu 3O 7-x (Y123) bulk superconductors have been processed using seeded infiltration growth technique (SIG). The combination of melt infiltrated liquid source (Ba 3Cu 5O 8) into the Y 2BaCuO 5 (Y211) pre-form and the nucleation of Y123 domain from SmBa 2Cu 3O 7 crystal seed has been investigated. The different configurations of SIG process were compared in this study. In addition, the effect of the starting Y211 particles size has been studied. The results reveal that, the Y211 particle size and different configurations strongly influence the properties of the final bulk superconductor sample.

  8. Large area, low microwave surface resistance thin films of YBa 2Cu 3O 7 prepared by pulsed laser ablation

    NASA Astrophysics Data System (ADS)

    Tian, Y. J.; Lu, H. B.; Xu, S. F.; Chen, Z. H.; Cui, D. F.; Zhou, Y. L.; Zhang, Y. Z.; Li, L.; Yang, G. Z.

    1994-02-01

    YBa 2Cu 3O 7 (YBCO) superconducting thin films were deposited on (100)LaAlO 3 substrates 35 mm in diameter by pulsed laser ablation. The substrates were heated resistively during deposition by a single-crystal Si heater and the laser beam was scanned on the rotating YBCO target. The films exhibited a thickness variation of ±3.7%, with zero resistance temperature Tc0 =90.6±0.6 K, critical current density Jc=2.9±0.9×10 6A/ cm2 at 77 K, and at 10 GHz a surface microwave resistance of <250μΩ at 77 K. The above-mentioned properties showed that high-quality YBCO thin films over a large substrate area can be obtained with this laser ablation system.

  9. Er3+ doped germanate-tellurite glass for mid-infrared 2.7 μm fiber laser material

    NASA Astrophysics Data System (ADS)

    Lu, Yu; Cai, Muzhi; Cao, Ruijie; Qian, Shan; Xu, Shiqing; Zhang, Junjie

    2016-03-01

    2.7 μm fluorescence has been achieved in the different concentration Er3+ doped germanate-tellurite glasses. The germanate-tellurite glass shows a good thermal stability and Fourier transform infrared spectra indicates that the mid-infrared transmission spectra performance is good. Based on the measured absorption spectra, the Judd-Ofelt parameters were calculated and discussed. Moreover, the emission spectra of Er3+ doped glasses show that the emission intensity at ~2.7 μm reaches a maximal value and no obvious concentration quenching phenomenon happens even if the ErF3-doping concentration is 1.5 mol%. In addition, the 2.7 μm radiative transition probability and emission cross section is 35.57 s-1 and 13.87×10-21 cm2 corresponding to the Er3+:4I11/2→4I13/2 transition and superior gain performance was also obtained from the prepared glass. Meanwhile, energy transfer mechanism has been investigated in detail. Hence, the spectroscopic characteristics as well as the good thermal property indicate that this kind of glass is an attractive host for developing mid-infrared fiber laser.

  10. Microwave heating-induced static magnetic flux penetration in YBa2Cu3O7-δ superconducting thin films

    NASA Astrophysics Data System (ADS)

    Kermorvant, Julien; Mage, Jean-Claude; Marcilhac, Bruno; Lemaître, Yves; Bobo, Jean-François; Jacominus van der Beek, Cornelis

    2012-06-01

    The magneto-optical imaging technique is used to visualize the penetration of the magnetic induction in YBa2Cu3O7-δ thin films during surface resistance measurements. The in situ surface resistance measurements were performed at 7 GHz using the dielectric resonator method. When only the microwave magnetic field Hrf is applied to the superconductor, no Hrf-induced vortex penetration is observed, even at high rf power. In contrast, in the presence of a constant magnetic field superimposed on Hrf, we observe a progression of the flux front as Hrf is increased. A local thermometry method based on the measurement of the resonant frequency of the dielectric resonator placed on the YBa2Cu3O7-δ thin film shows that the Hrf-induced flux penetration is due to the increase of the film temperature.

  11. Synthesis and properties of amides of 1-benzyl-3-methyl- and 1-butyl-3-phenyl-7-methyl-4-oxo-2-thioxo (2,4-dioxo)-1,2,3,4-tetrahydropyrido-[2,3-d]pyrimidine-6-carboxy lic acids.

    PubMed

    Sladowska, H; Zawisza, T

    1986-12-01

    Amides of 1-benzyl-3,7-dimethyl-4-oxo-2-thioxo-1,2,3,4- tetrahydropyrido[2,3]pyrimidine-6-carboxylic acid were obtained by the condensation of ammonia, primary and secondary cyclic amines with the corresponding acid chloride. As by - products amides of 1-benzyl-3,7-dimethyl-2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyr imidine-6- carboxylic acid were isolated as a result of desulfuration. The same reaction performed with chloride of 1-butyl-7-methyl-3-phenyl-4-oxo-2-thioxo-1,2,3,4-tetrahydropyri do[2,3- d]pyrimidine-6-carboxylic acid gave mainly the corresponding 2,4-dioxo-amides. PMID:3556569

  12. In-situ superconducting YBa2Cu3O7 thin films grown by ion beam co-deposition

    NASA Astrophysics Data System (ADS)

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

    1989-12-01

    We present superconducting YBa2C3O7 (YBCO) thin films grown in-situ by three-ion-beam sputtering. Y, Y2O3, Cu, Cu2O, BaF2 and BaCO3 sputter targets have been investigated. The highest quality films were prepared using a BaCO3 target. Auger analysis of films grown using a BaCO3 target show no carbon content. Y2O3 and Cu2O are more suitable than the native metals as sputter targets for YBCO growth as they are much less prone to sputter rate variations with oxygen partial pressure. They also supply oxygen to the growing film. As-deposited YBCO films are metallic (resistivity 240 μΩ cm at 100 K), reflective, and of highly homogeneous composition with TCO transition temperatures of 73 K and transition widths of 15 K. Post-annealing in flowing oxygen improves TCO's to 82 K. Critical currents are in excess of 105 A cm-2 at 77 K. Films are textured with c-axis orientation perpendicular to the (100) SrTiO3 substrate surface. As-deposited superconducting YBCO films have also been prepared on SiO2 and Y2O3 buffer layers on Si wafers.

  13. Investigations on the synthesis and pharmacological properties of amides of 7-methyl-3-phenyl-1-[2-hydroxy-3-(4-phenyl-1-piperazinyl)propyl]-2,4- dioxo-1,2,3,4-tetrahydropyrido[2,3-d]-pyrimidine-5-carboxylic acid.

    PubMed

    Sladowska, H; Sieklucka-Dziuba, M; Rajtar, G; Sadowski, M; Kleinrok, Z

    1999-01-01

    Synthesis of amides of 7-methyl-3-phenyl-2,4-dioxo-1,2,3,4- tetrahydropyrido[2,3-d]pyrimidine-5-carboxylic acid (6-10) and their 1-[2-hydroxy-3(4-phenyl-1-piperazinyl)propyl] derivatives (11-15) are described. Some of them displayed strong analgesic activity. PMID:10668178

  14. The fabrication of YBa sub 2 Cu sub 3 O sub 7 thin films by thermal coevaporation in oxygen

    SciTech Connect

    Wiesmann, H.; Chen, De Huai.

    1989-01-01

    Thin films of YBa{sub 2}Cu{sub 3}O{sub 7} have been fabricated by the technique of thermal coevaporation in oxygen. Details of the deposition system design and process are presented. Preliminary results are presented for films grown on magnesium oxide substrates. The films are characterized by x-ray diffraction and the quality of their superconducting transition. 10 refs., 3 figs.

  15. Synthesis and Anti-HCV Activity of 4-Methoxy-7H-Pyrrolo[2,3-d] Pyrimidine Carbocyclic Nucleosides.

    PubMed

    Thiyagarajan, Anandarajan; Toyama, Masaaki; Baba, Masanori; Sharon, Ashoke; Bal, Chandralata

    2016-06-01

    The present study includes the exploration of new possible nucleoside mimetics based on 4-methoxy-7H-pyrrolo[2,3-d]pyrimidine carbocyclic nucleosides (4a-g), which were synthesized by 10-15 synthetic steps and characterized adequately. We report the anti-HCV activities and cytotoxicities of 4a-g. Compound 4a was analyzed by single crystal X-ray diffraction which showed some puckering in the cyclopentene ring with a 2'-endo conformation and anti-base disposition (χ = -125.7°). PMID:27152477

  16. Molecular mechanism of inhibition of estrogen-induced cathepsin D gene expression by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in MCF-7 cells

    SciTech Connect

    Krishnan, V.; Porter, W.; Santostefano, M.; Wang, Xiahong

    1995-12-01

    This report describes how 17{beta}-estradiol (E2) induces cathepsin D gene expression, but is inhibited by the aryl hydrocarbon receptor by disruption of the estrogen receptor/pBC12/S1/pac plasmid complex by interaction with an overlapping xenobiotic responsive element. It was also determined that 2,3,7,8-tetrachlorobenzo-p-dioxin (TCDD) alone does not affect cathepsin D gene expression but can together with E2 to affect the rate of transcription and levels of immunoreactive protein. 85 refs., 6 figs., 2 tabs.

  17. Pump saturation effect of the Er3+/Yb3+ co-doped Y2Ti2O7 phosphors containing nanocrystals

    NASA Astrophysics Data System (ADS)

    Song, Feng; Wang, Fengxiao; Zhang, Jun; Chen, Gui-Yang; Feng, Ming

    2014-03-01

    Er3+ and Yb3+ co-doped Y2Ti2O7 phosphors containing nanocrystals were prepared by sol-gel method and annealed at 800 °C for 1 h in air. The X-ray diffraction (XRD) and transmission electron microscope (TEM) images showed that the mean size of nano-crystals is about 40-50nm, which corresponds well with the calculated results by Scherrer equation. Photoluminescence spectra and its upconversion properties were investigated. The anomalous slopes of the fitted line in the log-log plots for upconversion emissions and the pump-saturation effect of near infrared (NIR) emission were observed in the nanocrystalline samples. The reasons for the highly efficient upconversion luminescence and pump-saturation effect of NIR emission were discussed by a theoretical model of practical Er3+/Yb3+ co-doped system based on the rate equations. This work is supported by International Cooperation Program sponsored by Ministry of Science and Technology (MOST) of People's Republic of China.

  18. 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.

  19. 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

  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. Ethyl 7'-(6-benz-yloxy-2,2-dimethyl-tetra-hydro-furo[3,2-d][1,3]dioxol-5-yl)-2-oxo-5',6',7',7a'-tetra-hydro-1'H,2H-spiro-[acenaphthyl-ene-1,5'-pyrrolo-[1,2-c][1,3]thia-zole]-6'-carboxyl-ate.

    PubMed

    Jagadeesan, G; Sethusankar, K; Prasanna, R; Raghunathan, R

    2012-08-01

    In the title compound, C(34)H(35)NO(7)S, the acenaphthyl-ene unit is essentially planar (r.m.s. deviation = 0.0335 Å). The pyrrolo-thia-zole ring system is folded about the bridging N-C bond; the thia-zolidine and pyrrolidine rings adopt S- and C-envelope conformations, respectively, with a 'butterfly' angle between the mean planes of 51.38 (10)°. The dioxolane and tetra-hydro-furan rings adopt O- and a C-envelope conformations, respectively, with a 'butterfly' angle between the mean planes of 57.12 (10)°. Two C atoms are each disordered over two positions with site-occupancy factors of 0.450 (7) and 0.550 (7). The crystal packing is stabilized by C-H⋯O inter-actions, generating an R(2) (2)(14) graph-set ring motif. PMID:22904945

  2. 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

  3. Atmosphere control during preparation of YBa sub 2 Cu sub 3 O sub 7- x magnet windings

    SciTech Connect

    Poeppel, R.B.; Dorris, S.E.; Picciolo, J.J.; Balachandran, U.; Lanagan, M.T.; Zhang, C.Z.; Merkle, K.; Gao, Y.; Dusek, J.T.

    1990-10-01

    Large coils of YBa{sub 2}Cu{sub 3}O{sub 7-x} can be fired successfully if the furnace atmosphere is carefully controlled. Organics added during processing produce CO{sub 2} during the initial portions of the firing schedule. Transmission electron microscopy of material fired in atmospheres containing various levels of CO{sub 2} clearly shows the extent of grain boundary degradation caused by CO{sub 2}. Coils with acceptable critical current density can be produced if the rate of CO{sub 2} removal is adequate. 9 refs., 4 figs., 1 tab.

  4. Synthesis and Fungicidal Activities of (Z/E)-3,7-Dimethyl-2,6-octadienamide and Its 6,7-Epoxy Analogues.

    PubMed

    Yang, Mingyan; Dong, Hongbo; Jiang, Jiazhen; Wang, Mingan

    2015-01-01

    In order to find new lead compounds with high fungicidal activity, (Z/E)-3,7-dimethyl-2,6-octadienoic acids were synthesized via selective two-step oxidation using the commercially available geraniol/nerol as raw materials. Twenty-eight different (Z/E)-3,7-dimethyl-2,6-octadienamide derivatives were prepared by reactions of (Z/E)-carboxylic acid with various aromatic and aliphatic amines, followed by oxidation of peroxyacetic acid to afford their 6,7-epoxy analogues. All of the compounds were characterized by HR-ESI-MS and ¹H-NMR spectral data. The preliminary bioassays showed that some of these compounds exhibited good fungicidal activities against Rhizoctonia solani (R. solani) at a concentration of 50 µg/mL. For example, 5C, 5I and 6b had 94.0%, 93.4% and 91.5% inhibition rates against R. solani, respectively. Compound 5f displayed EC50 values of 4.3 and 9.7 µM against Fusahum graminearum and R. Solani, respectively. PMID:26610465

  5. Retrospective cohort study between selective and standard C3-7 laminoplasty. Minimum 2-year follow-up study

    PubMed Central

    Asazuma, Takashi; Masuoka, Kazunori; Yasuoka, Hiroki; Motosuneya, Takao; Sakai, Tsubasa; Nemoto, Koichi

    2007-01-01

    A total of 64 patients with cervical spondylotic myelopathy (CSM) were assessed in this study. Forty-two patients underwent selective expansive open-door laminoplasty (ELAP). Twenty-two patients who underwent conventional C3-7 ELAP served as controls. There were no significant differences in recovery rate of JOA scores, C2–C7 angle or cervical range of motion between two groups. Incidence of axial symptoms and segmental motor paralysis in selective ELAP was significantly lower than those in the C3-7 ELAP. Size of anterior compression mass, postoperative spinal cord positions and decompression conditions were evaluated using preoperative or postoperative MRI in 50 of 64 patients. There was a positive correlation between number of expanded laminae and maximum anterior spaces of spinal cord. Incomplete decompression was developed in three of 37 patients in selective ELAP and in two of 13 patients in C3-7ELAP. Mean size of anterior compression mass at incomplete decompression levels was significantly greater than that at complete decompression levels. Since, there was less posterior movement of the spinal cord in selective ELAP than that in C3-7ELAP, minute concerns about size of anterior compression mass is necessary to decide the number of expanded laminae. Overall, selective ELAP was less invasive and useful in reducing axial symptoms and segmental motor paralysis. This new surgical strategy was effective in improving the surgical outcomes of CSM, and short-term results were satisfactory. PMID:17726618

  6. 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.

  7. 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

  8. 40 CFR 721.9575 - Chromate(3-), bis[3-[[5-(aminosulfonyl)-2-hydroxyphenyl]azo]-4-hydroxy-7-[[2-oxo-1-[(phenylamino...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Chromate(3-), bis azo]-4-hydroxy-7... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.9575 Chromate(3-), bis azo... significant new uses subject to reporting. (1) The chemical substance identified as chromate(3-), bis...

  9. 40 CFR 721.9575 - Chromate(3-), bis[3-[[5-(aminosulfonyl)-2-hydroxyphenyl]azo]-4-hydroxy-7-[[2-oxo-1-[(phenylamino...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Chromate(3-), bis azo]-4-hydroxy-7... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.9575 Chromate(3-), bis azo... significant new uses subject to reporting. (1) The chemical substance identified as chromate(3-), bis...

  10. 40 CFR 721.9575 - Chromate(3-), bis[3-[[5-(aminosulfonyl)-2-hydroxyphenyl]azo]-4-hydroxy-7-[[2-oxo-1-[(phenylamino...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Chromate(3-), bis azo]-4-hydroxy-7... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.9575 Chromate(3-), bis azo... significant new uses subject to reporting. (1) The chemical substance identified as chromate(3-), bis...

  11. 40 CFR 721.9575 - Chromate(3-), bis[3-[[5-(aminosulfonyl)-2-hydroxyphenyl]azo]-4-hydroxy-7-[[2-oxo-1-[(phenylamino...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Chromate(3-), bis azo]-4-hydroxy-7... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.9575 Chromate(3-), bis azo... significant new uses subject to reporting. (1) The chemical substance identified as chromate(3-), bis...

  12. 40 CFR 721.9575 - Chromate(3-), bis[3-[[5-(aminosulfonyl)-2-hydroxyphenyl]azo]-4-hydroxy-7-[[2-oxo-1-[(phenylamino...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Chromate(3-), bis azo]-4-hydroxy-7... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.9575 Chromate(3-), bis azo... significant new uses subject to reporting. (1) The chemical substance identified as chromate(3-), bis...

  13. Broken particle-hole symmetry at atomically flat a-axis YBa2Cu3O7-delta interfaces.

    PubMed

    Davidson, Bruce A; Ramazashvili, Revaz; Kos, Simon; Eckstein, James N

    2004-09-01

    We have studied quasiparticle tunneling into atomically flat a-axis films of YBa(2)Cu(3)O(7-delta) and DyBa(2)Cu(3)O(7-delta) through epitaxial CaTiO3 barriers. The junction heterostructures were grown by oxide molecular beam epitaxy and were carefully optimized using in situ monitoring techniques, resulting in unprecedented crystalline perfection of the superconductor-insulator interface. Below T(c), the tunneling conductance shows the evolution of a large unexpected asymmetrical feature near zero-bias. This is evidence that superconducting YBCO crystals, atomically truncated along the lobe direction with a titanate layer, have intrinsically broken particle-hole symmetry over macroscopically large areas. PMID:15447441

  14. 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.

  15. 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.

  16. Thermally activated flux dissipation in [ital c]-axis-oriented YBa[sub 2]Cu[sub 3]O[sub 7]/PrBa[sub 2]Cu[sub 3]O[sub 7] multilayers

    SciTech Connect

    Qiu, X.G.; Zhao, B.R.; Guo, S.Q.; Zhang, J.R.; Li, L. ); Ichikawa, F.; Nishizaki, T.; Fukami, T.; Horie, Y.; Aomine, T. )

    1993-06-01

    We have systematically studied the resistive transition of multilayers of YBa[sub 2]Cu[sub 3]O[sub 7]/PrBa[sub 2]Cu[sub 3]O[sub 7] (YBCO/PBCO) under different perpendicular magnetic fields. It was found that the resistive transition is dominated by the flux-thermal-activation process; the broadening of the resistive transition was observed with the same order as that in single-layer thin films and the resistivity obeys the relation [rho]=[rho][sub 0] exp([minus][ital U]/[ital kT]). The activation energy depends logarithmically on the applied magnetic fields and decreased linearly with temperature. This phenomenon may be attributed to the creation of edge-dislocation pairs in the two-dimensional pancake vortices situated in the individual YBCO layer. The possible pinning mechanisms in the multilayers are discussed.

  17. Synthesis and anti-DNA viral activities in vitro of certain 2,4-disubstituted-7-(2-deoxy-2-fluoro-beta-D-arabinofuranosyl)pyrrolo[2,3-d d pyrimidine nucleosides.

    PubMed

    Bhattacharya, B K; Ojwang, J O; Rando, R F; Huffman, J H; Revankar, G R

    1995-09-29

    Several novel 2,4-disubstituted-7-(2-deoxy-2-fluoro-beta-D- arabinofuranosyl)pyrrolo[2,3-d]pyrimidines have been synthesized and evaluated for their anti-human cytomegalovirus (HCMV), anti-hepatitis B virus (HBV), and anti-herpes simplex virus (HSV) activities in vitro. These nucleosides were prepared starting from 2-amino-4-chloro-7-(2-deoxy-2-fluoro- 3,5-di-O-benzoyl-beta-D-arabinofuranosyl)pyrrolo[2,3-d]pyrimidine (3), which in turn was synthesized by direct glycosylation of the sodium salt of 2-amino-4-chloropyrrolo[2,3-d]pyrimidine (1) with 2-deoxy-2-fluoro-3,5-di-O-benzoyl-alpha-D-arabinofuranosyl bromide (2). Displacement of the 4-chloro group of 3 with OH, NH2, NHOH, SH, and SeH nucleophiles furnished the corresponding nucleosides 6-8, 12, and 14, respectively. The 3'-deoxygenation of 2-amino-4-chloro-7- (2-deoxy-2-fluoro-beta-D-arabinofuranosyl)pyrrolo[2,3-d]pyrimidine (4) and subsequent amination gave 2,4-diamino-2',3'-dideoxy derivative 19. Catalytic hydrogenation of 3 followed by debenzoylation afforded 2-aminopyrrolo[2,3-d]pyrimidine nucleoside 23. Among the compounds evaluated for their ability to inhibit the growth of HCMV (strain AD169) in MRC-5 cells using a plaque reduction assay, only 7 was significantly active in vitro with a 50% inhibitory concentration (IC50) of 3.7 micrograms/mL (TI > 125), whereas the IC50 value of ganciclovir (DHPG) was 3.2 micrograms/mL. Strain D16 of HCMV was more resistant to 7 (IC50 11 micrograms/mL) than the AD169 strain. When 7 was tested in combination with DHPG, the resultant anti-HCMV activity was found to be moderately synergistic with no evidence of antagonism. Nucleoside 7 also reduced episomal HBV replication in human hepatoblastoma 2.2.15 cells with an IC50 of 0.7 micrograms/mL (TI > 143). Development of cells harboring HBV which had become resistant to the drug was not observed with 7. Compound 7 also exhibited significant activity against herpes simplex virus types 1 and 2 (IC50 of 4.1 and 6.3 micrograms

  18. Natural strong pinning sites in laser-ablated YBa2Cu3O7-δ thin films

    NASA Astrophysics Data System (ADS)

    Huijbregtse, J. M.; Dam, B.; van der Geest, R. C. F.; Klaassen, F. C.; Elberse, R.; Rector, J. H.; Griessen, R.

    2000-07-01

    At low temperatures dislocations are the dominant flux-pinning centers in thin films of YBa2Cu3O7-δ deposited on (100) SrTiO3 substrates [B. Dam et al., Nature (London) 399, 439 (1999)]. Using a wet-chemical etching technique in combination with atomic force microscopy, both the length and the lateral dislocation distribution are determined in laser ablated YBa2Cu3O7-δ films. We find that (i) dislocations are induced in the first stages of film growth, i.e., close to the substrate-film interface, and persist all the way up to the film surface parallel to the c axis, resulting in a uniform length distribution, and (ii) the radial dislocation distribution function exhibits a universal behavior: it approaches zero at small distances, indicating short-range ordering of the defects. This self-organization of the growth-induced correlated disorder makes epitaxial films completely different from single crystals with randomly distributed columnar defects created by means of heavy-ion irradiation. Since the substrate temperature can be used to tune the dislocation density ndisl over almost two orders of magnitude (~1-100/μm2), the mechanism by which dislocations are induced is closely related to the YBa2Cu3O7-δ nucleation and growth mechanism. We present evidence for preferential precipitation in the first monolayer and precipitate generated dislocations.

  19. 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.

  20. 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.