WorldWideScience

Sample records for high tc greater

  1. Superconducting bolometers: high-Tc and low-Tc

    Science.gov (United States)

    Richards, Paul L.

    1991-07-01

    A description is given of recent work at Berkeley on superconducting detectors and mixers for infrared and millimeter wavelengths. The first report is a review article which summarizes the status of development of superconducting components for infrared and millimeter wave receivers. Next, a report is given on measurements and theoretical modeling of the absorptivity (surface resistance) of high quality epitaxial films of the high-Tc superconductor YBCO from 750 GHz to 21 THz. The next report describes measurements of the thermal boundary resistance between YBCO films and various substrates. This resistance is much larger than expected from the acoustic impedance mismatch model and gives a thermal time constant in the nanosecond range for typical YBCO films. Reports are also included on the design and experimental performance of two different types of high-Tc bolometric detectors. One is a conventional bolometer with a gold-black absorber. The other is an antenna coupled microbolometer. The properties of a low-Tc microbolometer are also described. The last reports describe accurate measurements and also theoretical modeling of an SIS quasi-particle waveguide mixer for W-band which uses very high quality Ta junctions. The best mixer noise is only 1.3 times the quantum limit. Both the mixer gain and the noise are in quantitative agreement with the quantum theory.

  2. Rugged Low-Resistance Contacts To High-Tc Superconductors

    Science.gov (United States)

    Caton, Randall; Selim, Raouf; Byvik, Charles E.; Buoncristiani, A. Martin

    1992-01-01

    Newly developed technique involving use of gold makes possible to fabricate low-resistance contacts with rugged connections to high-Tc superconductors. Gold diffused into specimen of superconducting material by melting gold beads onto surface of specimen, making strong mechanical contacts. Shear strength of gold bead contacts greater than epoxy or silver paste. Practical use in high-current-carrying applications of new high-Tc materials, including superconducting magnets, long-wavelength sensors, electrical ground planes at low temperatures, and efficient transmission of power.

  3. High Tc as a consequence of structure deformation

    Energy Technology Data Exchange (ETDEWEB)

    Djajic, R.P. (Faculty of Technical Sciences, Univ. of Novi Sad (Yugoslavia)); Tosic, B.S.; Setrajcic, J.P. (Inst. of Physics, Univ. of Novi Sad (Yugoslavia)); Mirjanic, D.L. (Faculty of Tech., Univ. of Banja Luka (Yugoslavia))

    1991-12-01

    Based on the experimental fact that doped perovskite structures behave as a system of energetically independent thin layers we developed a theoretical model for a single layer behaviour. It was shown that electron and phonon spectra are functions of azimuthal angle which in turn gives the specific relations for Tc which on the other hand differs significantly from the corresponding value in the BCS theory. The crucial fact, which allows the solution of this equation with high Tc, is the electron-electron interaction constant which in a thin doped layer is for an order or two orders of magnitude greater than the same interaction constant in the ideal infinite structure. (orig.).

  4. Grain boundaries in high-Tc superconductors

    NARCIS (Netherlands)

    Hilgenkamp, H.; Mannhart, J.

    2002-01-01

    Since the first days of high-Tc superconductivity, the materials science and the physics of grain boundaries in superconducting compounds have developed into fascinating fields of research. Unique electronic properties, different from those of the grain boundaries in conventional metallic supercondu

  5. Shock compaction of high- Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Weir, S.T.; Nellis, W.J.; McCandless, P.C.; Brocious, W.F. (Lawrence Livermore National Lab., CA (USA)); Seaman, C.L.; Early, E.A.; Maple, M.B. (California Univ., San Diego, La Jolla, CA (USA). Dept. of Physics); Kramer, M.J. (Ames Lab., IA (USA)); Syono, Y.; Kikuchi, M. (Tohoku Univ., Sendai (Japan))

    1990-09-01

    We present the results of shock compaction experiments on high-{Tc} superconductors and describe the way in which shock consolidation addresses critical problems concerning the fabrication of high J{sub c} bulk superconductors. In particular, shock compaction experiments on YBa{sub 2}Cu{sub 3}O{sub 7} show that shock-induced defects can greatly increase intragranular critical current densities. The fabrication of crystallographically aligned Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} samples by shock-compaction is also described. These experiments demonstrate the potential of the shock consolidation method as a means for fabricating bulk high-{Tc} superconductors having high critical current densities.

  6. New superconductors from granular to high T$_{c}$

    CERN Document Server

    Deutscher, Guy

    2006-01-01

    How new are the high Tc superconductors, as compared to the conventional low Tc ones? In what sense are these oxides different from regular metals in their normal state? How different is the mechanism for high Tc superconductivity from the well-known electron-phonon interaction that explains so well superconductivity in metals and alloys? What are the implications of the new features of the high Tc oxides for their practical applications? This book aims to give some answers to those questions, drawing particularly on similarities between the high Tc oxides and granular superconductors, which also present a maximum of their critical temperature near the metal-insulator transition.

  7. New superconductors from granular to high T$_{c}$

    CERN Document Server

    Deutscher, Guy

    2017-01-01

    How new are the high Tc superconductors, as compared to the conventional low Tc ones? In what sense are these oxides different from regular metals in their normal state? How different is the mechanism for high Tc superconductivity from the well-known electron-phonon interaction that explains so well superconductivity in metals and alloys? What are the implications of the new features of the high Tc oxides for their practical applications? This interesting book aims to provide some answers to those questions, drawing particularly on similarities between the high Tc oxides and granular superconductors, which also present a short coherence length, a small superfluid density and an inhomogeneous structure.

  8. High-Tc superconducting quantum interference device recordings of spontaneous brain activity: Towards high-Tc magnetoencephalography

    Science.gov (United States)

    Öisjöen, F.; Schneiderman, J. F.; Figueras, G. A.; Chukharkin, M. L.; Kalabukhov, A.; Hedström, A.; Elam, M.; Winkler, D.

    2012-03-01

    We have performed single- and two-channel high transition temperature (high-Tc) superconducting quantum interference device (SQUID) magnetoencephalography (MEG) recordings of spontaneous brain activity in two healthy human subjects. We demonstrate modulation of two well-known brain rhythms: the occipital alpha rhythm and the mu rhythm found in the motor cortex. We further show that despite higher noise-levels compared to their low-Tc counterparts, high-Tc SQUIDs can be used to detect and record physiologically relevant brain rhythms with comparable signal-to-noise ratios. These results indicate the utility of high-Tc technology in MEG recordings of a broader range of brain activity.

  9. Unconventional high-Tc superconductivity in fullerides.

    Science.gov (United States)

    Takabayashi, Yasuhiro; Prassides, Kosmas

    2016-09-13

    A3C60 molecular superconductors share a common electronic phase diagram with unconventional high-temperature superconductors such as the cuprates: superconductivity emerges from an antiferromagnetic strongly correlated Mott-insulating state upon tuning a parameter such as pressure (bandwidth control) accompanied by a dome-shaped dependence of the critical temperature, Tc However, unlike atom-based superconductors, the parent state from which superconductivity emerges solely by changing an electronic parameter-the overlap between the outer wave functions of the constituent molecules-is controlled by the C60 (3-) molecular electronic structure via the on-molecule Jahn-Teller effect influence of molecular geometry and spin state. Destruction of the parent Mott-Jahn-Teller state through chemical or physical pressurization yields an unconventional Jahn-Teller metal, where quasi-localized and itinerant electron behaviours coexist. Localized features gradually disappear with lattice contraction and conventional Fermi liquid behaviour is recovered. The nature of the underlying (correlated versus weak-coupling Bardeen-Cooper-Schrieffer theory) s-wave superconducting states mirrors the unconventional/conventional metal dichotomy: the highest superconducting critical temperature occurs at the crossover between Jahn-Teller and Fermi liquid metal when the Jahn-Teller distortion melts.This article is part of the themed issue 'Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene'.

  10. Electron Spin Pairing in High-Tc Superconductors

    Institute of Scientific and Technical Information of China (English)

    郭卫; 韩汝珊

    2001-01-01

    An electron pairing theory based on effective electron spin coupling mediated by antiferromagnetically correlated local moments is presented to account for high-Tc phenomena. We show that Kondo scattering and the suppression of the antiferromagnetic superexchange between Cu2+ moments lead to local triplet pairing, the mechanism underlying high-Tc superconductivity.

  11. Resonance of High Tc Superconducting Microstrip Patch in a Substrate-Superstrate Configuration

    Directory of Open Access Journals (Sweden)

    S. Benkouda

    2014-02-01

    Full Text Available The effect of a protecting dielectric superstrate on the resonance of a high Tc superconducting microstrip patch is investigated. The analysis approach is based on the spectral-domain method of moments in conjunction with the complex resistive boundary condition. The complex surface impedance of the superconducting thin film is determined using London’s equation and the two-fluid model of Gorter and Casimir. Numerical results show that the resonant frequency of the high Tc superconducting rectangular patch decreases monotonically with increasing superstrate thickness, the decrease being greater for high permittivity loading.

  12. High Tc superconducting fabrication of loop antenna

    Directory of Open Access Journals (Sweden)

    Widad Mahmood Faisal

    2012-09-01

    Full Text Available Using a solid state reaction to prepared many samples of YBa2Cu3O7−δ And (YBa2Cu3O7−δ1−x(Ag2Ox by mixing the appropriate ratios of constituent oxides; BaO, CuO, and Y2O3 the mixture were ground to fine power and then calcined at 900 °C without Ag2O and 930 °C for using Ag2O as impurities. The calcined black power were grounded again and molded into pellets by applying a hydrostatic pressure from (0.3–0.6 Gpa. These pellets were sintered at 950 °C. Silver was added as impurities with the calcined powder with ratios of 0.3, 0.35 and 0.45 to increase its ductility. The transition temperature for the superconductor samples were done using non-contact technique. It is an easy and sensitive technique compared with four – point probe method. The maximum Tc was 110 K for YBa2Cu3O6.989. Evaporation deposition technique to deposited a thin film, of 2200 A° thickness on the surface of the samples and then annealed to room temperature. This technical reduces the resistance to 0.2 Ω and makes a good ohmic contact at liquid nitrogen boiling point (77 K metals of various conductivity such as copper, brass aluminum and iron were used to study the effect of eddy-current loss on them and then compared with the superconducting samples, with Ag2O or without Ag2O. The maximum power loss were obtained for the superconducting samples when they cooling at liquid nitrogen temperature. The sintered pellets were drilled manually by 6 mm drill and a slot was done along its radius, to fabricate a superconducting loop antenna for receiving magnetic field signal. The best received signal was obtained when the antenna cooled to liquid nitrogen temperature.

  13. Nanoengineering of Flux Pinning Sites in High-Tc Superconductors

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Volume pinning forces were determined for a variety of bulk high-Tcsuperconductors of the 123-type from magnetization measurements. By means of scaling of the pinning forces, the acting pinning mechanisms in various temperature ranges were identified. The Nd-based superconductors and some YBCO crystalsexhibited a dominating pinning of the δTc-type (i.e., small, superconducting pinning sites). In contrast to this, the addition of insulating 211 particles provided pinning of the δl-type; providing effective pinning in the entire temperature range acting as a "background" pinning mechanism for the peak effect. Due to the small coherence lengths of the high-Tc compounds, effective pinning sites are defects or particles of nanometer size relative to ξ3. Integral magnetic measurements of the magnetization as a function of temperature in large applied magnetic fields (up to 7 T) revealed that practically all high-Tc compounds were spatially inhomogeneous, which could be caused byoxygen deficiency (YBCO), solid solutions of Nd/Ba (NdBCO and other light rare earth compounds), intergrowths (Bi-based superconductors), and doping by pair-breaking dopants like Zn, Pr. This implies that the superconducting sample consists of stronger and weaker superconducting areas, coupled together. In large appliedfields, this coupling gets broken and the magnetization versus temperature curves revealed more than one superconducting transition. In contrast, irradiation experiments by neutrons, protons, and heavy-ions enabled the artificial introduction of very effective pinning sites into the high-Tc superconductors, thus creating a large variety of different observations using magnetic data. From all these observations, we construct a pinning diagram for bulk high-Tc superconductors explaining many features observed in high-Tc samples.

  14. An Economical Magnetocardiogram System Based on High-Tc SQUIDs

    Institute of Scientific and Technical Information of China (English)

    LI Zhuo; ZHU Xue-Min; ZHANG Li-Hua; HUANG Xu-Guang; REN Yu-Feng; CHEN Geng-Hua; YANG Qian-Sheng; FENG Ji

    2006-01-01

    @@ An economical magnetocardiogram (MCG) system is built in our laboratory. It mainly consists of a MCG data acquisition stage equipped with two high-Tc superconducting quantum interference device (SQUID) magnetometers,a data processing stage with digital filtering and a one-layer μ-metal magnetically shielded room in conjunction with a high-Tc SQUID based active compensation. Experimental results show that a noise level of pico-tesla in MCG profiles, which is necessary for clinical applications, may be achieved with the system. Moreover, stable and convenient operations of the system are demonstrated with simulating MCG measurements.

  15. Superconducting Gap Anisotropy vs Doping Level in High- Tc Cuprates

    Science.gov (United States)

    Kendziora, C.; Kelley, R. J.; Onellion, M.

    1996-07-01

    We report the results of electronic Raman scattering in Bi2Sr2CaCu2O8+δ (Bi2212) and Tl2Ba2CuO6+δ (Tl2201) high-Tc superconductors with variations in the oxygen content. Near optimal doping, both materials show gap anisotropy, with 2Δ/kBTc values of 7.2 ( B1g) vs 5.8 ( A1g) in Tl2201 and 8.5 ( B1g) vs 6.2 ( A1g) in Bi2212. However, overdoped samples exhibit a symmetry independent gap with 2Δ/kBTc ranging from 5.2 for Bi2212 ( Tc = 57 K) to 3.9 in Tl2201 ( Tc = 37 K). We compare the data with calculations using both isotropic s-wave and d-wave order parameters.

  16. Plasma resonance in anisotropic layered high-Tc superconductors

    DEFF Research Database (Denmark)

    Sakai, Shigeki; Pedersen, Niels Falsig

    1999-01-01

    The plasma resonance is described theoretically by the inductive coupling model for a large stacked Josephson-junction system such as the intrinsic Josephson-junction array in anisotropic high- T-c superconductors. Eigenmodes of the plasma oscillation are analytically described and a numerical...

  17. Directly coupled slotted high-Tc dc SQUIDs

    NARCIS (Netherlands)

    Jansman, A.B.M.; Izquierdo, M.; Flokstra, J.; Rogalla, H.

    1999-01-01

    A flux quantization model gives estimates for the effective area and washer inductance of slotted high-Tc dc SQUIDs. The inductance prediction has not been verified yet. Here, the theoretical dependence of washer inductance and effective area for four slotted SQUID types on the London penetration de

  18. Peltier effect in the mixed state of high- Tc superconductors

    Science.gov (United States)

    Logvenov, G. Yu.; Ryazanov, V. V.; Ustinov, A. V.; Huebener, R. P.

    1991-04-01

    The Peltier and Seebeck effects in the mixed state of high- Tc superconductors are proportional to the resistivity due to flux motion. Therefore, both effects also show the broadening of the transition regime characteristic for these superconductors. The origin of the Peltier effect is discussed in detail, and the validity of the Thomson relation is confirmed, as expected.

  19. Technical issues of a high-Tc superconducting bulk magnet

    Science.gov (United States)

    Fujimoto, Hiroyuki

    2000-06-01

    Superconducting magnets made of high-Tc superconductors are promising for industrial applications. It is well known that REBa2Cu3O7-x superconductors prepared by melt processes have a high critical current density, Jc, at 77 K and high magnetic fields. The materials are very promising for high magnetic field applications as a superconducting permanent/bulk magnet with liquid-nitrogen refrigeration. Light rare-earth (LRE) BaCuO bulks, compared with REBaCuO bulks, exhibit a larger Jc in high magnetic fields and a much improved irreversibility field, Hirr, at 77 K. In this study, we discuss technical issues of a high-Tc superconducting bulk magnet, namely the aspects of the melt processing for bulk superconductors, their characteristic superconducting properties and mechanical properties, and trapped field properties of a superconducting bulk magnet. One of the possible applications is a superconducting bulk magnet for the magnetically levitated (Maglev) train in the future.

  20. High-Tc superconductor coplanar waveguide filter

    Science.gov (United States)

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

    1991-01-01

    Coplanar waveguide (CPW) low-pass filters made of YBa2Cu3O(7-delta) (YBCO) on LaAlO3 substrates, with dimensions suited for integrated circuits, were fabricated and packaged. A complete filter gives a true idea of the advantages and difficulties in replacing thin-film metal with a high-temperature superconductor in a practical circuit. Measured insertion losses in liquid nitrogen were superior to the loss of a similar thin-film copper filter throughout the 0- to 9.5-GHz passband. These results demonstrate the performance of fully patterned YBCO in a practical CPW structure after sealing in a hermetic package.

  1. High Tc: The Discovery of RBCO

    Science.gov (United States)

    Chu, C. W.

    2007-03-01

    It was said by Emerson that ``there is no history; there is only biography.'' This is especially true when the events are recounted by a person who, himself, has been heavily involved and the line between history and autobiography can become blurred. However, it is reasonable to say that discovery itself is not a series of accidents but an inevitable product of each development stage of scientific knowledge as was also pointed out by Holden et al. (1) The discovery of RBCO (2,3) with R = Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu is no exception. In this presentation, I will briefly recount several events that were crucial to the discovery of RBCO: those before 1986 (4) that sowed the seeds in our group important to our later high temperature superconductivity effort; those in 1986 (5) that were critical to our discovery of the 93 K RBCO soon after the discovery of the 35 K high temperature superconductor by M"uller and Bednorz (6); and those in 1987 when the barrier of the liquid nitrogen boiling temperature of 77 K was finally conquered. 1. G. J. Holton et al., American Scientist 84, 364 (1996). 2. M. K. Wu et al., Phys. Rev. Lett. 58, 908 (1987). 3. P. H. Hor et al., Phys. Rev. Lett. 58, 1891 (1987). 4. C. W. Chu et al., S. S. Comm. 18, 977 (1976); C. W. Chu and V. Diatchenko, Phys. Rev. Lett. 41, 572 (1978); T. H. Lin et al., Phys. Rev. B(RC) 29, 1493 (1984); J. H. Lin et al., J. Low Temp. Phys. 58, 363 (1985). 5. C. W. Chu et al., Phys. Rev. Lett. 58, 405 (1987); C. W. Chu et al., Science 235, 567 (1987). 6. J. G. Bednorz and K. A. M"uller, Z. Phys. B64, 189 (1986).

  2. Producing Ceramic High Tc Superconductors for Strong Current Applications

    Institute of Scientific and Technical Information of China (English)

    Jian-Xun Jin; Yuan-Chang Guo; Xue-Kei Fu; Shi-Xue Dou

    2000-01-01

    @@ Strong current and large-scale application is the most important prospect of high Tc superconductors (HTS).Practical HTS samples, both in forms of wire and bulk, have been produced with high critical currents operated at economic cryogenic temperatures, and studied for engineering applications with various prototype devices. The applicable HTS materials produced are introduced in this paper with regard to processing, characterization and application.

  3. Enhancement of Structure, Tc and Irreversibility Line in High Tc Superconductors by Heat Treatments

    Directory of Open Access Journals (Sweden)

    Abdeljabar Aboulkassim

    2015-08-01

    Full Text Available AC susceptibility (ac= ’+ i‖ and X ray diffraction (XRD are very useful for characterizing high Tc superconductors. We report here on the preparation, X-ray diffraction with Rietveld refinement, resistivity , AC magnetic susceptibility measurements and effect of heat treatments in (Y1-xNdxSrBaCu3O6+z. Each sample was subject to two types of heat treatment: oxygen annealing [O] and argon annealing followed by oxygen annealing [AO]. For each x, the [AO] heat treatment increases the orthorhombicity ε = (b-a/(b+a (for 0≤x0.2, the distance d[Cu(1-(Sr/Ba] (for x0.25; increase in cationic and chain oxygen ordering; psh and in-phase purity for the [AO] samples may account for the observed data.

  4. NMR/MRI with hyperpolarized gas and high Tc SQUID

    Science.gov (United States)

    Schlenga, Klaus; de Souza, Ricardo E.; Wong-Foy, Annjoe; Clarke, John; Pines, Alexander

    2000-01-01

    A method and apparatus for the detection of nuclear magnetic resonance (NMR) signals and production of magnetic resonance imaging (MRI) from samples combines the use of hyperpolarized inert gases to enhance the NMR signals from target nuclei in a sample and a high critical temperature (Tc) superconducting quantum interference device (SQUID) to detect the NMR signals. The system operates in static magnetic fields of 3 mT or less (down to 0.1 mT), and at temperatures from liquid nitrogen (77K) to room temperature. Sample size is limited only by the size of the magnetic field coils and not by the detector. The detector is a high Tc SQUID magnetometer designed so that the SQUID detector can be very close to the sample, which can be at room temperature.

  5. Mean field theory of high Tc cuprate superconductivity

    Directory of Open Access Journals (Sweden)

    K. Maki

    2006-09-01

    Full Text Available   Two decades ago the epoch making discovery of high Tc cuprate superconductivity by Bednorz and Müller shocked the world’s superconductivity community. However, already in 1979 and 1980, the first heavy fermion superconductor CeCu2Si2 and organic superconductor (TMTSF2PF6 have been discovered respectively. Also we know now that all these superconductors are unconventional and nodal. Further the quasiparticles in the normal state in these systems are Fermi liquids and the superconducting states are described in terms of generalized BCS wave function. Also the pseudogap phase in underdoped high Tc cuprates is described in terms of d-wave density wave. This implies necessarily that the superconductivity in underdoped cuprates is gossamer (i.e. d-wave superconductivity coexists with d-wave density wave. We shall present some quantitative tests of these new concepts, notions and ideas.

  6. High-spin states in the {sup 97}Tc nucleus

    Energy Technology Data Exchange (ETDEWEB)

    Bucurescu, D.; Cata-Danil, G.; Cata-Danil, I.; Ivascu, M.; Marginean, N.; Rusu, C.; Stroe, L.; Ur, C.A. [National Institute of Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest 76900 (Romania); Gadea, A. [INFN, Laboratori Nazionali di Legnaro, Legnaro (Italy)

    2003-04-01

    High-spin states in the {sup 97}Tc nucleus have been studied by in-beam {gamma}-ray spectroscopy with the reaction {sup 82}Se({sup 19}F,4n{gamma}) at 68 MeV incident energy. Excited states have been observed up to about 8 MeV excitation and spin 43/2{Dirac_h}. The observed level scheme is compared with results of shell model calculations. (orig.)

  7. A high-Tc superconductor bolometer on a silicon nitridemembrane

    NARCIS (Netherlands)

    Sanchez, S.; Elwenspoek, M.C.; Gui, C.; Nivelle, de M.J.M.E.; Vries, de R.; Korte, de P.A.J.; Bruijn, M.P.; Schwierzi, B.

    1997-01-01

    In this paper we describe the design, fabrication and performance of a high-Tc GdBa2Cu3O7-δ superconductor bolometer positioned on a 2×2 mm2, 1 μm thick silicon nitride membrane. The bolometer structure has an effective area of 0.64 mm2 and was grown on a specially developed silicon-on-nitride layer

  8. High Tc Superconductor Theoretical Models and Electromagnetic Flux Characteristics

    Institute of Scientific and Technical Information of China (English)

    JIN Jian-xun

    2006-01-01

    High Tc Superconductors (HTS) have special electromagnetic characteristics and phenomena. Effort has been made in order to theoretically understand the applied HTS superconductivity and HTS behaviors for practical applications, various theoretical models related to the HTS electromagnetic properties have been developed. The theoretical models and analytic methods are summarized with regard to understanding the HTS magnetic flux characteristic which is one of the most critical issues related to HTS applications such as for HTS magnetic levitation application.

  9. High-spin states in the {sup 96}Tc nucleus

    Energy Technology Data Exchange (ETDEWEB)

    Bucurescu, D.; Cata-Danil, G.; Cata-Danil, I.; Ivascu, M.; Marginean, N.; Rusu, C.; Stroe, L.; Ur, C.A. [National Inst. of Physics and Nuclear Engineering, Bucharest (Romania); Gizon, A.; Gizon, J. [Inst. des Sciences Nucleaires, IN2P3-CNRS/UPJ, Grenoble (France); Nyako, B.; Timar, J.; Zolnai, L. [Inst. of Nuclear Research, Debrecen (Hungary); Boston, A.J.; Joss, D.T.; Paul, E.S.; Semple, A.T. [Oliver Lodge Lab., Liverpool Univ. (United Kingdom); Parry, C.M. [Dept. of Physics, York Univ., Heslington, York (United Kingdom)

    2001-03-01

    High-spin states in the {sup 96}Tc nucleus have been studied with the reactions {sup 82}Se({sup 19}F,5n{gamma}) at 68 MeV and Zn({sup 36}S,{alpha}pxn) at 130 MeV. Two {gamma}-ray cascades (irregular bandlike structures) have been observed up to an excitation energy of about 10 MeV and spin 21-22{Dirac_h}. (orig.)

  10. Weak Coupling Electron-Phonon for High Tc Superconductors

    Science.gov (United States)

    Labbe, J.

    1989-01-01

    Our opinion is that, in the high Tc copper oxides, the electronic correlations are not large enough to allow the localization of the electrons of the half-filled d-p sub-band. Thus, we treat them as itinerant electrons, in a bidimensional structure. And we show that, contrary to a widely held opinion, the electron-phonon interaction can induce high Tc superconductivity in these compounds, even in the weak coupling limit. This is due to the fact that, because of the bidimensionality, the electronic density of states is sharply peaked in the neighbourhood of the Fermi energy. A small coupling between nearest neighbouring CuO2 planes is sufficient to prevent a very large reduction of Tc by the critical fluctuations. The calculated isotope effect is much smaller than usually in the BCS theory. And, in our weak coupling theory, the antiferromagnetic (AF) phase is much more rapidly destabilized by dopping or internal charge transfer than the superconducting phase, which takes place when the AF phase has vanished.

  11. High- Tc superconductivity: new issues from photoemission data

    Science.gov (United States)

    Margaritondo, G.; Grioni, M.; Vobornik, I.; Pavuna, D.

    2001-11-01

    Recent high-resolution photoemission results on high- Tc superconductors and other low-dimensional systems solve some critical issues but also open new fundamental questions. A recent breakthrough enabled us to clarify the interplay of conflicting periodicities in photoemission data, thus legitimizing the photoemission analysis of crystals with super-periodicities. On the other hand, results on the role of doping and of intentional disorder in Bi 2Sr 2CaCu 2O 8+ x single crystals raise questions about the origin of the pseudogap.

  12. Applications using high-Tc superconducting terahertz emitters

    Science.gov (United States)

    Nakade, Kurama; Kashiwagi, Takanari; Saiwai, Yoshihiko; Minami, Hidetoshi; Yamamoto, Takashi; Klemm, Richard A.; Kadowaki, Kazuo

    2016-03-01

    Using recently-developed THz emitters constructed from single crystals of the high-Tc superconductor Bi2Sr2CaCu2O8+δ, we performed three prototype tests of the devices to demonstrate their unique characteristic properties for various practical applications. The first is a compact and simple transmission type of THz imaging system using a Stirling cryocooler. The second is a high-resolution Michelson interferometer used as a phase-sensitive reflection-type imaging system. The third is a system with precise temperature control to measure the liquid absorption coefficient. The detailed characteristics of these systems are discussed.

  13. Scanning high-Tc SQUID imaging system for magnetocardiography

    Science.gov (United States)

    Yang, Hong-Chang; Wu, Tsung-Yeh; Horng, Herng-Er; Wu, Chau-Chung; Yang, S. Y.; Liao, Shu-Hsien; Wu, Chiu-Hsien; Jeng, J. T.; Chen, J. C.; Chen, Kuen-Lin; Chen, M. J.

    2006-05-01

    A scanning magnetocardiography (MCG) system constructed from SQUID sensors offers potential to basic or clinical research in biomagnetism. In this work, we study a first order scanning electronic high-Tc (HTS) SQUID MCG system for biomagnetic signals. The scanning MCG system was equipped with an x-y translation bed powered by step motors. Using noise cancellation and μ-metal shielding, we reduced the noise level substantially. The established scanning HTS MCG system was used to study the magnetophysiology of hypercholesterolaemic (HC) rabbits. The MCG data of HC rabbits were analysed. The MCG contour map of HC rabbits provides experimental models for the interpretation of human cardiac patterns.

  14. Microstructures and critical currents in high-{Tc} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Suenaga, Masaki

    1998-11-01

    Microstructural defects are the primary determining factors for the values of critical-current densities in a high {Tc} superconductor after the electronic anisotropy along the a-b plane and the c-direction. A review is made to assess firstly what would be the maximum achievable critical-current density in YBa{sub 2}Cu{sub 3}O{sub 7} if nearly ideal pinning sites were introduced and secondly what types of pinning defects are currently introduced or exist in YBa{sub 2}Cu{sub 3}O{sub 7} and how effective are these in pinning vortices.

  15. Analysis of sup 99m Tc-labeled radiopharmaceuticals by high-performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Muto, Toshio (Tokyo Metropolitan Isotope Research Center (Japan))

    1990-02-01

    High-performance liquid chromatography (HPLC) equiped with on line radiometric and optical detectors (i.e. radio-HPLC) have been applied to the radiochemical analysis of commonly-used {sup 99m}Tc-radio pharma ceuticals with a view point to check the radiochemical purities of the compounds. Chromatographic conditions were determined by examination of the types of column, mobile phase and pH. An aqueous size-exclusion (Shim-pack Diol-300) and reversed-phase column (Zorbax-ODS) were found to be suitable for {sup 99m}Tc-HSA and the other {sup 99m}Tc-agents, respectively. The analysis of low molecular weight {sup 99m}Tc-agents (e.g. {sup 99m}Tc-DTPA, {sup 99m}Tc-DMSA, {sup 99m}Tc-pyrophosphate, {sup 99m}Tc-phytic acid, {sup 99m}Tc-MDS, {sup 99m}Tc-HMDP) were done by reversed-phaseion pairing chromatography using a optimized mobile phase consisted on a mixture of 50 mM phosphate buffer (pH 7.0) and 2 mM TBA (tetra nbutyl) ammonium hydroxide in 30 % methanol. The mobile phases for analysis of medium molecular weight {sup 99m}Tc-HSA were consisted of a mixture of 50 mM phosphate buffer (ph 7.0) in 30 % methanol, and a mixtures of 1 % SDS (sodium dodecyl sulfonate) in Tris buffer (pH. 7.0), respectively. It was apparent from the radio-chromatograms obtained from these chromatographic conditions, that impurity of {sup 99m}TcO{sub 4} was observed in {sup 99m}Tc-pyrophosphate, {sup 99m}Tc-phytic acid, {sup 99m}Tc-MDP, {sup 99m}Tc-HMDP, and impurities of {sup 99m}Tc-labeled species and {sup 99m}TcO{sub 4}, were observed in {sup 99m}Tc-HIDA, {sup 99m}Tc-HIDA, {sup 99m}Tc-HSA. The radiochemical impurities of the {sup 99m}Tc-radiopharmaceuticals were ranged between 90 and 100 %. From these results, radio-HPLC has been shown to be suitable method for analysis of {sup 99m}Tc-radiopharmaceuticals, with rapidity and excellent precision. (author).

  16. Deformation processing of high-Tc superconducting oxides

    Science.gov (United States)

    Rajan, K.; German, R. M.; Knorr, D. B.; Maccrone, R. K.; Misiolek, W.; Wright, R. N.

    1989-04-01

    Plastic deformation and texture development in polycrystalline YBa2Cu3O7- δ has been studied to expedite the process development of high-critical-temperature (high-Tc) superconducting wires and tapes. It is anticipated that deformation texture will be a major processing consideration in terms of maximizing critical current density, assessing conductor-fabrication options in light of critical current density, and developing such mechanical properties as strength, toughness and thermal fatigue. The intrinsic texture development in YBa2Cu3O7- δ deformation processing should be highly beneficial, insofar as the c axes of the crystals tend to become oriented along the compression axis. This means that conducting tapes and wires formed by rolling, extrusion and drawing can develop textures with the c axis in the transverse or radial direction, thus maximizing the flow of current along the length of the conductor.

  17. International Discussion Meeting on High-Tc Superconductors

    CERN Document Server

    1988-01-01

    In the past two years conferences on superconductivity have been characterized by the attendance of hundreds of scientists. Consequently, the organizers were forced to schedule numerous parallel sessions and poster presentations with an almost unsurveyable amount of information. It was, therefore, felt that a more informal get-together, providing ample time for a thourough discussion of some topics of current interest in high-temperature superconductivity, was timely and benefitial for leading scientists as well as for newcomers in the field. The present volume contains the majority of papers presented at the International Discussion Meeting on High-Tc Superconductors held at the Mauterndorf Castle in the Austrian Alps from February 7 to 11, 1988. Each subject was introduced in review form by a few invited speakers and then discussed together with the contributed poster presentations. These discussion sessions chaired by selected scientists turned out to be the highlights of the meeting, not only because all ...

  18. Modeling of tunneling spectroscopy in high-TC superconductors

    Science.gov (United States)

    Shukrinov, Yu. M.; Namiranian, A.; Najafi, A.

    2001-01-01

    The tunneling density of states of high-Tc superconductors is calculated taking into account the tight-binding band structure, group velocity, and tunneling directionality for s-wave and d-wave gap symmetry. The characteristic density of states has asymmetry of the quasiparticle peaks, flat s-wave and cusplike d-wave subgap behavior, and an asymmetric background. It is assumed that the underlying asymmetry of the conductance peaks is primarily due to the features of the quasiparticle energy spectrum and that the d-wave symmetry enhances the degree of asymmetry of the peaks. Increasing the lifetime broadening factor changes the degree of asymmetry of the tunneling conductance peaks and leads to confluence of the quasiparticle and van Hove singularity peaks.

  19. Buffer layers for high-Tc thin films on sapphire

    Science.gov (United States)

    Wu, X. D.; Foltyn, S. R.; Muenchausen, R. E.; Cooke, D. W.; Pique, A.; Kalokitis, D.; Pendrick, V.; Belohoubek, E.

    1992-01-01

    Buffer layers of various oxides including CeO2 and yttrium-stabilized zirconia (YSZ) have been deposited on R-plane sapphire. The orientation and crystallinity of the layers were optimized to promote epitaxial growth of YBa2Cu3O(7-delta) (YBCO) thin films. An ion beam channeling minimum yield of about 3 percent was obtained in the CeO2 layer on sapphire, indicating excellent crystallinity of the buffer layer. Among the buffer materials used, CeO2 was found to be the best one for YBCO thin films on R-plane sapphire. High Tc and Jc were obtained in YBCO thin films on sapphire with buffer layers. Surface resistances of the YBCO films were about 4 mOmega at 77 K and 25 GHz.

  20. High-Tc Superconductors Based on FeAs Compounds

    CERN Document Server

    Izyumov, Yuri

    2010-01-01

    Physical properties and models of electronic structure are analyzed for a new class of high-TC superconductors which belong to iron-based layered compounds. Despite their variable chemical composition and differences in the crystal structure, these compounds possess similar physical characteristics, due to electron carriers in the FeAs layers and the interaction of these carriers with fluctuations of the magnetic order. A tremendous interest towards these materials is explained by the prospects of their practical use. In this monograph, a full picture of the formation of physical properties of these materials, in the context of existing theory models and electron structure studies, is given. The book is aimed at a broad circle of readers: physicists who study electronic properties of the FeAs compounds, chemists who synthesize them and specialists in the field of electronic structure calculations in solids. It is helpful not only to researchers active in the fields of superconductivity and magnetism, but also...

  1. Buffer layers for high-Tc thin films on sapphire

    Science.gov (United States)

    Wu, X. D.; Foltyn, S. R.; Muenchausen, R. E.; Cooke, D. W.; Pique, A.; Kalokitis, D.; Pendrick, V.; Belohoubek, E.

    1992-01-01

    Buffer layers of various oxides including CeO2 and yttrium-stabilized zirconia (YSZ) have been deposited on R-plane sapphire. The orientation and crystallinity of the layers were optimized to promote epitaxial growth of YBa2Cu3O(7-delta) (YBCO) thin films. An ion beam channeling minimum yield of about 3 percent was obtained in the CeO2 layer on sapphire, indicating excellent crystallinity of the buffer layer. Among the buffer materials used, CeO2 was found to be the best one for YBCO thin films on R-plane sapphire. High Tc and Jc were obtained in YBCO thin films on sapphire with buffer layers. Surface resistances of the YBCO films were about 4 mOmega at 77 K and 25 GHz.

  2. Moderately shielded high-Tc SQUID system for rat MCG

    Science.gov (United States)

    Bechstein, S.; Kim, I.-S.; Drung, D.; Novikov, I.; Schurig, Th

    2010-06-01

    Recently, we have developed a 5-channel high-Tc SQUID system with one signal channel intended for rat magnetocardiography (MCG) in moderately shielded or "quiet" real environment. This system is an adapted version of a human MCG system which has been improved with respect to user-friendliness and stability. A dewar with a cold-warm distance of 7 mm and a refill cycle time of up to one week is utilized. The implemented high-Tc SQUIDs are single-layer devices with grain boundary junctions fabricated at KRISS with laser ablation on 10 mm × 10 mm STO substrates. In order to cancel environmental magnetic noise, three of the five SQUIDs are arranged to build an axial software first-order or second-order gradiometer with a base line of 35 mm. The other two SQUIDs are used for balancing. To overcome previous system instabilities, we have implemented an Earth field compensation for each SQUID. For this, the SQUIDs were mounted in capsules containing integrated field compensation coils. The three Earth field components are measured with an additional triaxial fluxgate, and compensated at the SQUID locations using the low-noise current source of the SQUID readout electronics. This way, the SQUIDs can be cooled and operated in a low residual field that improves system stability and reduces low-frequency SQUID noise. It is even possible to slowly move the dewar in the Earth field (dynamic field compensation). Different noise cancellation procedures were optimized and compared employing a periodic signal source.

  3. First 13 Years of HIGH-Tc:. Brief Review and Open Questions

    Science.gov (United States)

    Pavuna, Davor

    Exactly 13 years ago, in April 1986, appeared the famous paper1 by Bednorz and Müller, that announced a striking discovery of high-Tc superconductivity in cuprates. Some 40'000 papers later, we are still struggling to understand the high-Tc superconductivity. Here I summarize some of the most relevant recent results and open questions by discussing the observed phenomena in a rather complex electronic phase diagram of high-Tc oxides.

  4. First 13 years of high-{Tc}: Brief review and open questions

    Energy Technology Data Exchange (ETDEWEB)

    Pavuna, D.

    1999-12-20

    Exactly 13 years ago, in April 1986, appeared the famous paper by Bednorz and Mueller, that announced a striking discovery of high-{Tc} superconductivity in cuprates. Some 40,000 papers later, scientists are still struggling to understand the high-{Tc} superconductivity. Here the author summarizes some of the most relevant recent results and open questions by discussing the observed phenomena in a rather complex electronic phase diagram of high-{Tc} oxides.

  5. On the application of High-Tc superconductors in power coils and transformers

    NARCIS (Netherlands)

    Chevtchenko, Oleg Alexandrovitch

    2002-01-01

    In this study, the electro-magnetic properties of high-Tc tapes and coils are investigated. The focus is on Bi-2223/Ag tapes with non-twisted superconducting filaments as these are the only high-Tc superconductors at present available in sufficient length for practical applications. The study is con

  6. A new mechanism for high-[Tc]: Electron scattering from interacting tunneling units

    Energy Technology Data Exchange (ETDEWEB)

    Klein, M.W.; Simanovsky, S.B. (Worcester Polytechnic Inst., MA (United States). Dept. of Physics)

    1998-12-20

    A theoretical model for high-[Tc] superconductivity is presented based on electron pairing due to their interaction with two-level or multi-level tunneling units (TU's) present in high-[Tc] materials. TU's were found experimentally in YBa[sub 2]Cu[sub 3]O[sub 7[minus][delta

  7. Origin of the high Neel temperature in SrTcO3

    OpenAIRE

    Mravlje, J.; Aichhorn, M; Georges, A.

    2011-01-01

    We investigate the origin of the high Neel temperature recently found in Tc perovskites. The electronic structure in the magnetic state of SrTcO3 and its 3d analogue SrMnO3 is calculated within a framework combining band-structure and many-body methods. In agreement with experiment, the Neel temperature of SrTcO3 is found to be four times larger than that of SrMnO3. We show that this is because the Tc-compound lies on the verge of the itinerant-to-localized transition, and also has a larger b...

  8. Surgical treatment of high-standing greater trochanter.

    Science.gov (United States)

    Takata, K; Maniwa, S; Ochi, M

    1999-01-01

    Eleven patients with high-standing greater trochanter (13 joints) aged 13-36 years underwent surgery. Distal transfer of the greater trochanter (group T) was performed in 4 patients (5 joints) and lateral displacement osteotomy (group L) in 7 (8 joints). The average follow-up duration was 13.4 years in group T and 5.9 years in group L. Clinical results were evaluated by the hip score according to Merle d'Aubigne. The mean hip score in group T was 13.4 points before operation and 15.4 points after operation, and in group L, 12.8 and 17.4 points, respectively. The postoperative clinical results of group L were significantly better than those of group T (P = 0.0494). In radiological evaluation, although the articulo-trochanteric distance (ATD) increased in both groups in group L it improved remarkably from 9.8 to 24.3, indicating a large descending distance of the greater trochanter. The lever arm ratio (LAR) did not change significantly in group T, but it decreased from 1.97 to 1.60 in group L (P = 0.004). This means that the lever arm of the abductors can certainly be extended by lateral displacement osteotomy. Lateral displacement osteotomy is the most effective procedure for high-standing greater trochanter.

  9. Comments on photoelectron spectroscopy of high- Tc 's

    Energy Technology Data Exchange (ETDEWEB)

    Arko, A.J.

    1991-01-01

    The photoemission discussion session during the Argonne conference on Fermiology of High-{Tc}'s provided a forum to air a number of unresolved issues in photoelectron spectroscopy. These are: (a) what is the exact energy dependence of the line width of the quasiparticle peaks: (b) are there any chemical potential shifts with hole doping; (c) why is a superconducting gap not observed in Y-123; and (d) different groups report different results in the band structure of Bi-2212. The first issue, while much discussed, essentially becomes a non-issue in the sense that nearly all theories predict a linear as well as a quadratic energy dependence to the quasiparticle lifetime. Furthermore, the data are not yet good enough to distinguish between linear and quadratic dependence in the important region within 0.1 eV of E{sub F}. Regarding chemical potential shifts, they very definitely are observed with hole doping both in Y-123 and Bi-2212 in spite of the claims by RVB enthusiasts to the contrary. In Y-123 the shifts are as large as 0.75 eV. The non-observation of a gap in Y-123 is puzzling, but may be related to surface reconstruction and an overdoped situation. The important question of whether we have one or two bands near E{sub F} in Bi-2212 revolves around the surface quality of the samples studied by different groups. It is difficult to compare data taken at room temperature vs. data taken at low temperature when no documentation exists that a reconstruction did not occur. We suspect that the small second band championed by the Sendai group is a surface impurity band.

  10. Progress and prospect on the research of new iron-based high-Tc superconductors

    Institute of Scientific and Technical Information of China (English)

    Xian-hui CHEN

    2010-01-01

    @@ Since the discovery of high-Tc copper oxides, researches on high-Tc superconductors and their physical mechanism have become one of the hottest topics in condensed matter physics. In conventional superconductors, superconductivity occurs at very low temperatures. When superconductive, a material presents zero resistance and diamagnetism which is called Meissner Effect. The highTc superconductors are the materials whose superconducting transition temperatures are beyond the McMillan limit of 39 K. However, up to now, the mechanism of the copper oxide superconductors is still under debate.

  11. Properties of HIGH-Tc Cuprates: Some Recent Results and Open Questions

    Science.gov (United States)

    Vobornik, Ivana; Pavuna, Davor

    Thirteen years ago, late in 1986, several groups confirmed striking claims of the famous paper by Bednorz and M[Z Phys. B 64 (1986) 189] that announced the discovery of high-Tc superconductivity in cuprates. Some 60,000 papers later, we are still struggling to understand the high-Tc oxide superconductivity. Here we present some of the most relevant recent experiments and discuss some open questions across rather complex electronic phase diagram; we also note an important role of un-intentional and intentional disorder in these layered, high-Tc oxides.

  12. Feshbach shape resonance for high Tc pairing in superlattices of quantum stripes and quantum wells

    Directory of Open Access Journals (Sweden)

    A Bianconi

    2006-09-01

    Full Text Available   The Feshbach shape resonances in the interband pairing in superconducting superlattices of quantum wells or quantum stripes is shown to provide the mechanism for high Tc superconductivity. This mechanism provides the Tc amplification driven by the architecture of material: superlattices of quantum wells (intercalated graphite or diborides and superlattices of quantum stripes (doped high Tc cuprate perovskites where the chemical potential is tuned to a Van Hove-Lifshitz singularity (vHs in the electronic energy spectrum of the superlattice associated with the change of the Fermi surface dimensionality in one of the subbands.

  13. A new family of high-Tc compounds-Stepping stones toward understanding unconventional superconductivity

    Institute of Scientific and Technical Information of China (English)

    SUN Yang; Mike GUIDRY; WU ChengLi

    2008-01-01

    @@ High-transition temperature (Tc) superconductivity was first discovered in layered copper-based oxides (cuprates)more than two decades ago[1], but its theoretical inter-pretation remains controversial[2,3]. The main question concerning the high-Tc superconductivity phase diagram is the transition between the antiferromagnetic (AF) and superconducting (SC) phases, which is dominated by anomalous properties commonly attributed to a pseu-dogap[4,5] in the spectrum. It is believed that the high-Tc mechanism in cuprates cannot be fully understood within the BCS theory[6] that explains normal supercon-ductivity. Despite much effort, there is no consensus as to the origin of the pseudogap properties, and the high-Tc mechanism remains an open question.

  14. High Affinity Immobilization of Proteins Using the CrAsH/TC Tag

    Directory of Open Access Journals (Sweden)

    Janine Schulte-Zweckel

    2016-06-01

    Full Text Available Protein microarrays represent important tools for biomedical analysis. We have recently described the use of the biarsenical-tetracysteine (TC tag for the preparation of protein microarrays. The unique feature of this tag enables the site-specific immobilization of TC-containing proteins on biarsenical-modified surfaces, resulting in a fluorescence enhancement that allows the direct quantification of the immobilized proteins. Moreover, the reversibility of the binding upon incubation with large quantities of thiols permits the detachment of the proteins from the surface, thereby enabling recovery of the substrate to extend the life time of the slide. Herein, we describe our recent results that further extend the applicability of the CrAsH/TC tag to the fabrication of biochips. With this aim, the immobilization of proteins on surfaces has been investigated using two different spacers and two TC tags, the minimal TC sequence (CCPGCC and an optimized motif (FLNCCPGCCMEP. While the minimal peptide motif enables a rapid recycling of the slide, the optimized TC sequence reveals an increased affinity due to its greater resistance to displacement by thiols. Moreover, the developed methodology was applied to the immobilization of proteins via on-chip ligation of recombinant protein thioesters.

  15. Plasma resonance and flux dynamics in layered high-Tc superconductors

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig; Sakai, S.

    2000-01-01

    Flux dynamics of layered high Tc superconductors are considered with special emphasis on the small oscillation modes. In particular we find the dispersion relation for the plasma modes and discuss the spectra to be observed in microwave experiments.......Flux dynamics of layered high Tc superconductors are considered with special emphasis on the small oscillation modes. In particular we find the dispersion relation for the plasma modes and discuss the spectra to be observed in microwave experiments....

  16. Models of high-Tc superconductivity and applications to electric generators and motors

    DEFF Research Database (Denmark)

    Sørensen, Mads Peter

    We present the Ginzburg Landau model for mesoscopic high-Tc superconductors of complex geometry. It is shown that giant vortices can form at boundary defects. The relation between total magnetic flux penetration through the superconductor and the externally applied field is established. This is i....... This is in turn used in modelling high-Tc superconducting generators proposed for windmills in the project SuperWind (http://www.superwind.dk)....

  17. Indelible Rules of Josephson Coupling Energy and Zero-Point Energy in High-Tc Cuprates

    Institute of Scientific and Technical Information of China (English)

    LIU Fu-Sui; CHEN Wan-Fang

    2004-01-01

    This paper shows that the Josephson coupling energy and the zero-point energy have indelible rules on the superfluid density and the superconductivity in the high-Tc cuprates.This paper also shows that the values of Tc at underdoped and overdoped regions are determined by the damage conditions of the phase coherence in the classical and the quantum XY-models,respectively.

  18. The doping dependence of T* - what is the real high-Tc phase diagram?

    OpenAIRE

    2000-01-01

    Underdoped high-Tc superconductors are frequently characterised by a temperature, T*, below which the normal-state pseudogap opens. Two different "phase diagrams" based on the doping (p) dependence of T* are currently considered: one where T* falls to zero at a critical doping state and the other where T* merges with Tc in the overdoped region. By examining the temperature dependence of the NMR Knight shift and relaxation rate, entropy, resistivity, infrared conductivity, Raman scattering, AR...

  19. Superfluid and normal fluid density in high- Tc superconductors

    Science.gov (United States)

    Tanner, D. B.; Liu, H. L.; Quijada, M. A.; Zibold, A. M.; Berger, H.; Kelley, R. J.; Onellion, M.; Chou, F. C.; Johnston, D. C.; Rice, J. P.; Ginsberg, D. M.; Markert, J. T.

    1998-01-01

    The electronic properties of the cuprate superconductors have been studied by measuring the reflectance over the frequency range from the far-infrared to the near-ultraviolet(roughly, 10 meV-5 eV). There is an interesting behavior in both the normal state and the superconducting state. In the normal state, there is the well-known non-Drude distribution of the doping-induced spectral weight. In the superconducting state, the spectral weight of the superconducting condensate correlates with Tc in a variety of materials. Remarkably, in optimally doped superconductors, only about 20% of the doping-induced carriers joins the superfluid; the rest of the spectral weight remains at finite frequencies.

  20. Superconducting fluctuations and pseudogap in high-Tc cuprates

    Directory of Open Access Journals (Sweden)

    Alloul H.

    2012-03-01

    Full Text Available Large pulsed magnetic fields up to 60 Tesla are used to suppress the contribution of superconducting fluctuations (SCF to the ab-plane conductivity above Tc in a series of YBa2Cu3O6+x. These experiments allow us to determine the field Hc’(T and the temperature Tc’ above which the SCFs are fully suppressed. A careful investigation near optimal doping shows that Tc’ is higher than the pseudogap temperature T*, which is an unambiguous evidence that the pseudogap cannot be assigned to preformed pairs. Accurate determinations of the SCF contribution to the conductivity versus temperature and magnetic field have been achieved. They can be accounted for by thermal fluctuations following the Ginzburg-Landau scheme for nearly optimally doped samples. A phase fluctuation contribution might be invoked for the most underdoped samples in a T range which increases when controlled disorder is introduced by electron irradiation. Quantitative analysis of the fluctuating magnetoconductance allows us to determine the critical field Hc2(0 which is found to be be quite similar to Hc’ (0 and to increase with hole doping. Studies of the incidence of disorder on both Tc’ and T* allow us to to propose a three dimensional phase diagram including a disorder axis, which allows to explain most observations done in other cuprate families.

  1. A New Mechanism for High-Tc:. Electron Scattering from Interacting Tunneling Units

    Science.gov (United States)

    Klein, Michael W.; Simanovsky, Sergey B.

    A theoretical model for high-Tc superconductivity is presented based on electron pairing due to their interaction with two-level or multi-level tunneling units (TU's) present in high-Tc materials. TU's were found experimentally in YBa2Cu3O7-δ, Bi2CaSr2Cu2O8, Tl2CaBa2Cu2O8 and in Tl2CaBa2CuO6. The TU's have specific directions of orientation with respect to the crystal axis and hence cause a strongly anisotropic scattering of the conduction electrons and a strongly anisotropic gap function Δ(k) with wave vector k. For the weak coupling case we obtain, (i) an analytically derived Δ(k) which has a linear combination of s-wave and dx2-y2-wave symmetry with nodes in Δ(k), (ii) a high-Tc determined by the elastic interaction potential between the TU's, (iii) an isotope effect consistent with experiment, (iv) a large uniaxial pressure p dependence of Tc for YBa2Cu3O7-δ close to optimal oxygen doping and (dTc/dpa) ≈ -(dTc/dpb) where Pa and Pb are the pressures in the a and b directions, (v) a quantitative agreement with experiment for dTc/dPi (i = a, b) when we use the elastic constant. The recently observed d ± s wave pairing in twinned YBa2Cu3O7-δ, with a reversal of the sign of s-wave component across the twin boundary, is also in agreement with our model.

  2. Defect-Induced Changes in the Spectral Properties of HIGH-Tc Cuprates

    Science.gov (United States)

    Vobornik, I.; Berger, H.; Rullier-Albenque, F.; Margaritondo, G.; Pavuna, D.; Grioni, L. Forroand M.

    Superconductivity in high-Tc cuprates is particularly sensitive to disorder due to the unconventional d-wave pairing symmetry. We investigated effects of disorder on the spectral properties of Bi2Sr2CaCu2O8+x high-Tc superconductor. We found that already small defect densities suppress the characteristic spectral signature of the superconducting state. The spectral line shape clearly reflects new excitations within the gap, as expected for defect-induced pair breaking. At the lowest defect concentrations the normal state remains unaffected, while increased disorder leads to suppression of the normal quasiparticle peaks.

  3. Low noise high-Tc superconducting bolometers on silicon nitride membranes for far-infrared detection

    NARCIS (Netherlands)

    Nivelle, de M.J.M.E.; Bruijn, M.P.; Vries, de R.; Wijnbergen, J.J.; Korte, de P.A.J.; Sanchez, S.; Elwenspoek, M.; Heidenblut, T.; Schwierzi, B.; Michalke, W.; Steinbeiss, E.

    1997-01-01

    High-Tc GdBa2Cu3O7 – delta superconductor bolometers with operation temperatures near 89 K, large receiving areas of 0.95 mm2 and very high detectivity have been made. The bolometers are supported by 0.62 µm thick silicon nitride membranes. A specially developed silicon-on-nitride layer was used to

  4. What makes the Tc of FeSe/SrTiO3 so high?

    Institute of Scientific and Technical Information of China (English)

    Dung-Hai Lee

    2015-01-01

    This paper reviews some of the recent progresses in the study of high temperature superconductivity in the interface between a single unit cell FeSe and SrTiO3. It offers the author’s personal view of why Tc is high and how to further increase it.

  5. Search for high-Tc conventional superconductivity at megabar pressures in the lithium-sulfur system

    Science.gov (United States)

    Kokail, Christian; Heil, Christoph; Boeri, Lilia

    2016-08-01

    Motivated by the recent report of superconductivity above 200 K in ultra-dense hydrogen sulfide, we search for high-TC conventional superconductivity in the phase diagram of the binary Li-S system, using ab initio methods for crystal structure prediction and linear response calculations for the electron-phonon coupling. We find that at pressures higher than 20 GPa, several new compositions, besides the known Li2S , are stabilized; many exhibit electride-like interstitial charge localization observed in other alkali-metal compounds. Of all predicted phases, only an fcc phase of Li3S , metastable before 640 GPa, exhibits a sizable TC, in contrast to what is observed in sulfur and phosphorus hydrides, where several stoichiometries lead to high TC. We attribute this difference to 2 s -2 p hybridization and avoided core overlap, and predict similar behavior for other alkali-metal compounds.

  6. Irradiation-induced disorder in high- Tc cuprates: electronic band structure study

    Science.gov (United States)

    Vobornik, I.; Quitmann, C.; Zacchigna, M.; Zwick, F.; Grioni, M.; Karkin, A.; Kelley, R. J.; Onellion, M.; Margaritondo, G.

    1998-05-01

    We used thermal neutron irradiation to produce disorder in Bi-2212 single crystals ( TC=85 K), at a constant carrier density. The irradiated samples were insulators. High-temperature superconductivity with a lower TC than prior to irradiation could be restored by a low-temperature annealing. We performed angle-resolved photoemission investigation on both unannealed (insulating) and annealed (superconducting) samples in order to study the corresponding changes in electronic structure. We observed a strong suppression of the spectral weight near the Fermi energy with increasing disorder. Our results demonstrate that effects related to disorder cannot be neglected in the interpretation of the spectral properties of cuprates.

  7. The influence of anharmonic phonons on the isotope effect in high-{Tc} oxides

    Energy Technology Data Exchange (ETDEWEB)

    Crespi, V.H.; Cohen, M.L.

    1992-01-01

    Anharmonic phonons are examined to study the unusual isotope effect exponents for the high-{Tc} oxides. Within a simple model of anharmonicity, the mass dependences of the electron-phonon coupling constant {lambda} and the phonon frequency determine the isotope effect exponent {alpha} as a function of coupling strength. A model in which the outer wells of a multiple-well potential deepen as the orthorhombic/low temperature tetragonal phase transition in La{sub 2-x}M{sub x}CuO{sub 4} is approached is consistent with some experimentally observed variations in {Tc} and {alpha}. 10 refs.

  8. The influence of anharmonic phonons on the isotope effect in high- Tc oxides

    Energy Technology Data Exchange (ETDEWEB)

    Crespi, V.H.; Cohen, M.L.

    1992-01-01

    Anharmonic phonons are examined to study the unusual isotope effect exponents for the high-{Tc} oxides. Within a simple model of anharmonicity, the mass dependences of the electron-phonon coupling constant {lambda} and the phonon frequency determine the isotope effect exponent {alpha} as a function of coupling strength. A model in which the outer wells of a multiple-well potential deepen as the orthorhombic/low temperature tetragonal phase transition in La{sub 2-x}M{sub x}CuO{sub 4} is approached is consistent with some experimentally observed variations in {Tc} and {alpha}. 10 refs.

  9. High T(c) superconductors: Technical and commercial challenge

    Science.gov (United States)

    Kirschner, I.; Horvath, E.; Vajda, I.; Bencze, L.; Goebl, N.

    1995-01-01

    Some basic questions of the way which leads from the discovery of high-T(c) superconductors to their applications is surveyed. The influence of high-T(c) superconducting technology on the industrial and social development is also briefly analyzed.

  10. Evaluation of Mo99 and Tc99m Productions Based on a High-Performance Cyclotron

    Directory of Open Access Journals (Sweden)

    J. Esposito

    2013-01-01

    Full Text Available Following preliminary feasibility studies which started at Legnaro National Laboratories (LNL in 2011, the Italian National Institute for Nuclear Physics (INFN research activities are underway aiming at the alternative, accelerator-driven, Mo99/Tc99m production routes. One of the most promising approaches is to use 100Mo-enriched (i.e., >99% molybdenum metallic targets, bombarded with high-beam-current, high-energy proton cyclotrons. In order to get a comprehensive map of radionuclides expected, a detailed theoretical investigation has been carried out using the TALYS-TENDL 2012 excitation functions extended up to (p,6n, (p,p5n, and (p,2p4n levels. A series of quality parameters have thus been calculated both at the end of beam (EOB and at longer times. Results point out that accelerator-99Mo is of limited interest for a possible massive production because of the quite low specific activity with respect to reactor-99Mo. Accelerator-Tc99m quality parameters (i.e., radionuclidic purity (RNP, isotopic purity (IP, and specific activities calculated are instead quite close to the generator-Tc. Calculations at 15, 20, and 25 MeV have thus been performed to assess the best operative irradiation condition for Tc99m production while minimizing both the short-lived and long-lived Tc contaminant radionuclides. Although present in minimum quantities, Tc contaminants may indeed have an impact either on the pharmaceutical labeling procedures or on contributing to patient radiation dose during the diagnostic procedures.

  11. Cathodoluminescence study of thin films of high Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Barkay, Z.; Azoulay, J.; Lereah, Y.; Dai, U.; Hess, N.; Racah, D.; Gruenbaum, E.; Deutscher, G. (School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 69978 Ramat Aviv (Israel))

    1990-10-22

    Cathodoluminescence (CL) of thin films of high {ital T}{sub {ital c}} superconductors was studied in the scanning electron microscope. The depth and the lateral locations of the different phases can be revealed. In thin films, unlike the bulk superconductors, the CL information can be obtained either from the film itself or the substrate by varying the primary beam energy. At high beam energy, substrate defects and slight thickness variations of a single high {ital T}{sub {ital c}} phase are observed. The resolution of the CL measurements improves at low temperatures.

  12. The 11th symposium of high Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hojou, Kiichi; Okayasu, Satoru; Sasase, Masato [eds.] [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-03-01

    This workshop was carried out on December 16 and 17, 1999, at JAERI, Tokai in a series of modification material by irradiation in 'the multi-core project II of the high temperature superconducting material research' organized by Science and Technology Agency. The following is the abstract of presentations concerning basic theories, various experimental results and material improvement of the superconductivity by high energy ion irradiation. (author)

  13. The 9th symposium of high Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hojou, Kiichi; Okayasu, Satoru; Sasase, Masato [eds.

    1998-03-01

    This workshop was carried out on December 11 and 12, 1997, at JAERI, Tokai in a series of modification of material by irradiation in `the multi core project II of the high temperature superconducting material research` organized by Science and Technology Agency. The following is the abstract of presentations concerning basic theories, various experimental results and material improvement of the superconductivity by high energy ion irradiation. The 26 papers are indexed individually. (J.P.N.)

  14. Note: A hand-held high-Tc superconducting quantum interference device operating without shielding.

    Science.gov (United States)

    He, D F

    2011-02-01

    By improving the compensation circuit, a hand-held high-Tc rf superconducting quantum interference devices (SQUID) system was developed. It could operate well when moving in unshielded environment. To check the operation, it was used to do eddy-current testing by hand moving the SQUID, and the artificial defect under 6 mm aluminum plate could be successfully detected in shielded environment.

  15. A high-Tc SQUID-based sensor head cooled by a Joule–Thomson cryocooler

    NARCIS (Netherlands)

    Rijpma, A.P.; Brake, ter H.J.M.; Vries, de E.; Nijhof, N.; Holland, H.J.; Rogalla, H.

    2002-01-01

    The goal of the so-called FHARMON project is to develop a high-Tc SQUID-based magnetometer system for the measurement of fetal heart activity in standard clinical environments. To lower the threshold for the application of this fetal heart monitor, it should be simple to operate. It is, therefore, a

  16. A high-Tc superconductor bolometer for remote sensing of atmospheric OH

    NARCIS (Netherlands)

    Nivelle, de M.J.M.E.; Bruijn, M.P.; Vries, de R.; Wijnbergen, J.J.; Korte, de P.A.J.; Sanchez, S.; Elwenspoek, M.; Heidenblut, T.; Schwierzi, B.; Michalke, W.; Steinbeiss, E.; Frericks, M.

    1996-01-01

    The technological feasibility is being investigated of a high-Tc superconductor transition edge bolometer for far-infrared detection, which can meet the requirements of a Fabry-Perot based satellite instrument designed for remote sensing of atmospheric OH. These include a time constant τ<0.3 s, an o

  17. Materials aspects of integrated high-Tc dc-SQUID magnetometer fabrication

    NARCIS (Netherlands)

    Hilgenkamp, J.W.M.; IJsselsteijn, R.P.J.; Rijnders, A.J.H.M.; Tavares, P.A.C.; Flokstra, J.; Rogalla, H.

    1993-01-01

    An integrated high Tc dc-SQUID magnetometer is being developed. It has in total 10 layers of five different materials. Various materials aspects of the fabrication process will be discussed, especially the smoothness of the films and the techniques to obtain smooth edges. Cross-overs and superconduc

  18. Closed-cycle gas flow system for cooling of high Tc d.c. SQUID magnetometers

    NARCIS (Netherlands)

    Bosch, van den P.J.; Holland, H.J.; Brake, ter H.J.M.; Rogalla, H.

    1995-01-01

    A high Tc.d.c SQUID based magnetometer for magnetocardiography is currently under development at the University of Twente. Since such a magnetometer should be simple to use, the cooling of the system can be realized most practically by means of a cryocooler. A closed-cycle gas flow cooling system in

  19. Peltier effect in the mixed state of high-Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Logvenov, G.Yu.; Ryazanov, V.V.; Ustinov, A.V.; Huebener, R.P. (Physikalisches Inst., Lehrstuhl Experimentalphysik 2, Univ. Tuebingen (Germany, F.R.))

    1991-04-01

    The Peltier and Seebeck effects in the mixed state of high-Tc superconductors are proportional to the resistivity due to flux motion. Therefore, both effects also show the broadening of the transition regime characteristic for these superconductors. The origin of the Peltier effect is discussed in detail, and the validity of the Thomson relation is confirmed, as expected. (orig.).

  20. Flux flow in high-Tc Josephson junctions

    DEFF Research Database (Denmark)

    Filatrella, G.; Pedersen, Niels Falsig

    1993-01-01

    The possibility of achieving fluxon nucleation in nonhysteretic high-T(c) Josephson junctions due to the presence of inhomogeneities is investigated numerically. For a large range of parameters the I- V characteristics in presence of such discontinuities show a strong similarity with those obtain...

  1. Measuring Thermal Diffusivity Of A High-Tc Superconductor

    Science.gov (United States)

    Powers, Charles E.; Oh, Gloria; Leidecker, Henning

    1992-01-01

    Technique for measuring thermal diffusivity of superconductor of high critical temperature based on Angstrom's temperature-wave method. Peltier junction generates temperature oscillations, which propagate with attenuation up specimen. Thermal diffusivity of specimen calculated from distance between thermocouples and amplitudes and phases of oscillatory components of thermocouple readings.

  2. Magnetoencephalography based on high-Tc superconductivity: a closer look into the brain?

    CERN Document Server

    Öisjöen, F; Figueras, G A; Chukharkin, M L; Kalabukhov, A; Hedström, A; Elam, M; Winkler, D

    2011-01-01

    Magnetoencephalography (MEG) enables the study of brain activity by recording the magnetic fields generated by neural currents and has become an important technique for neuroscientists in research and clinical settings. Unlike the liquid-helium cooled low-Tc superconducting quantum interference devices (SQUIDs) that have been at the heart of modern MEG systems since their invention, high-Tc SQUIDs can operate with liquid nitrogen cooling. The relaxation of thermal insulation requirements allows for a reduction in the stand-off distance between the sensor and the room-temperature environment from a few centimeters to less than a millimeter, where MEG signal strength is significantly higher. Despite this advantage, high-Tc SQUIDs have only been used for proof-of-principle MEG recordings of well-understood evoked activity. Here we show high-Tc SQUID-based MEG may be capable of providing novel information about brain activity due to the close proximity of the sensor to the head. We have performed single- and two-...

  3. Quasiclassical Theory of Twin Boundaries in High-Tc Superconductors

    OpenAIRE

    Belzig, Wolfgang; Bruder, Christoph; Sigrist, Manfred

    1998-01-01

    We investigate the electronic structure of twin boundaries in orthorhombically distorted high-T$_c$ materials using the quasiclassical theory of superconductivity. At low temperatures we find a local instability to a time-reversal symmetry breaking state at the twin boundary. This state yields spontaneous currents along the twin boundary that are microscopically explained by the structure of the quasiparticle bound states. We calculate the local density of states and find a splitting in the z...

  4. Program to Study AC Loss in High-Tc Superconductors

    Science.gov (United States)

    2007-11-02

    electric field. But similarities occur in that Bean models and modified Bean models can be used in both cases. In the high-7c case the two critical...loss results for low-7c material, replacing jc with j™’*’’. The same is true of modified Bean models where jcmter becomes a function of//. The...simplified by neglecting any time decay of the critical current density and using a strict Bean model of constant critical current density. (Since

  5. Temperature Dependence of Growth Mechanism for Nanoscale High Tc Superconductors

    Institute of Scientific and Technical Information of China (English)

    Wu-Ming Chen; Mustafa Yavuz; Jian-Xun Jin

    2008-01-01

    The growth mechanisms of high temper- ature Yttrium- and Bismuth-based-superconductors were investigated at nanoscale. We started with studying the growth relationships among the three phases of Bi-2201, Bi-2212, and Bi-2233, and then extended to another growth mechanism of Bi-2223 and the growth of yttrium-based high-temperature nanosupercon- ductors (nano-YBCO). A time dependence of growth experiment was performed. In this experiment, the Bi-based superconductors grew within different sintering periods, and its three phases were determined by X-ray diffraction. And then, a time dependence of growth model was suggested to explain the experimental facts. With this model, governing equations were derived to quantitatively describe the growth and decomposition mechanisms during sintering period. The results calculated from the derived equations were well in agreement with the experimental data. We also suggested an alternative growth mechanism for the Bi-2223 phase, which was supported by an observation of transmission electron microscopy (TEM). The nano-YBCO also grew, and their orthorhombic crystal structures were determined by the TEM. The superconducting properties of Bi-2223 were investigated by the measurements of ac magnetic susceptibility. It is expected that the derived equations will fit the alter- native experimental growth mechanism of the Bi-2223 phase and the nano-YBCO growth mechanism, too.

  6. Melt processing of bulk high Tc superconductors and their application

    Science.gov (United States)

    Murakami, M.; Oyama, T.; Fujimoto, H.; Gotoh, S.; Yamaguchi, K.

    1991-03-01

    The authors report a melt-powder-melt-growth (MPMG) process which results in high Jc for bulk Y-Ba-Cu-O superconductors. The Y-Ba-Cu-O pellets or powders are melt quenched. The quenched plates are crushed into powder and mixed well. The powder is then compacted into desired shapes, remelted, and slowly cooled in a thermal gradient. When the starting composition is changed from the 1:2:3 stoichiometry toward the Y2BaCuO5(211) rich region, the 211 inclusions can be dispersed in the YBa2Cu3O(x) matrix, which contributes to increases in both flux pinning force and fracture toughness. A Jc value exceeding 3 x 108 A/sq m has been achieved at 77 K and 1 T. Another attractive feature of the MPMG process is that other components such as fine Ag powders can be added during solid-state mixing. Fine dispersion of Ag particles can effectively reduce the amount of cracking. MPMG-processed Y-Ba-Cu-O with Ag doping can levitate a mass of 3-kg at 1-mm height using a repulsive force against a 0.4-T magnet. A noncontacting rotation device such as a magnetic bearing can be made utilizing bulk high-Jc materials. A superconducting permanent magnet is also a promising candidate for future application. MPMG-processed Y-Ba-Cu-O can generate 0.25 T at 77 K.

  7. Early High Tc Activity in Japan: The Franco Rasetti Lecture

    Science.gov (United States)

    Tanaka, Shoji

    2007-03-01

    From 1960 to 1980, R&D of superconductivity in Japan was carried out mainly to improve A15 superconducting wires and magnets. Improvement of wires were made mainly in the National Institute for Metals, and improvements of superconducting magnets were made in the Japan Atomic Energy Research Institute for future nuclear fusion reactors, the National Railway Laboratory for future maglev trains and also in the Electo-Technical Laboratory for MHD generators. I began the research of BPBO in 1975 and at that time the research of oxide superconductors was limited only to my laboratory in the University of Tokyo. During the study of this new superconductor, we learned quite a lot on how to make ceramic samples, how to measure electrical conductivity and magnetic susceptibility at low temperatures. In 1982, Prof. S. Nakajima organized a rather small group for investigating ``New Superconducting Phenomena,'' and I became a member of the group. In 1985, Nakajima expanded the research group to include more than 5 experimentalists and 5 theoreticians. The title of the research was ``New Superconducting Materials'' and the funds came from the Ministry of Education of Japan. In late October, 1986, we followed the first paper of Bednorz and Muller, and immediately found the material includes high temperature superconductor and reported it to the group meeting held in early November. In early December, we confirmed La2-xBaxCuO4 is the real high temperature superconductor, the critical temperature is 28K. I sent a copy of our paper to Prof. Beasley of California and asked to inform this fact to his colleagues. Asahi Shimbun, the biggest newspaper in Japan announced this in its science section, and then many people knew the high temperature superconductor had been discovered. Then many physicists and chemists rushed to this field very quickly and many kinds of materials were synthesized. In the Government, the Ministry of Education, the Ministry of International Trade and Industry

  8. Jahn–Teller physics and high-Tc superconductivity

    Directory of Open Access Journals (Sweden)

    Hugo Keller

    2008-09-01

    Full Text Available The discovery of high-temperature superconductivity in copper oxides was not accidental, but was based on the knowledge that the divalent copper ion, Cu2+, is one of the strongest Jahn–Teller ions. The Jahn–Teller effect is a consequence of the interplay between electronic degeneracy and coupling to the lattice, i.e. unconventional local electron–lattice interactions. The search for superconductivity in copper oxides was motivated by the idea that Jahn–Teller polaron formation could be a novel and much stronger glue for electron pairing than conventional Bardeen–Cooper–Schrieffer electron–phonon coupling. The consequences of these ideas are unconventional isotope effects and complex pairing symmetries related to multiband superconductivity, which are reviewed here.

  9. The unusually high Tc in rare-earth-doped single crystalline CaFe2As2

    Science.gov (United States)

    Wei, Fengyan; Lv, Bing; Deng, Liangzi; Meen, James K.; Xue, Yu-Yi; Chu, Ching-Wu

    2014-08-01

    In rare-earth-doped single crystalline CaFe2As2, the mysterious small volume fraction which superconducts up to 49 K, much higher than the bulk Tc ~ 30 s K, has prompted a long search for a hidden variable that could enhance the Tc by more than 30% in iron-based superconductors of the same structure. Here we report a chemical, structural and magnetic study of CaFe2As2 systematically doped with La, Ce, Pr and Nd. Coincident with the high Tc phase, we find extreme magnetic anisotropy, accompanied by an unexpected doping-independent Tc and equally unexpected superparamagnetic clusters associated with As vacancies. These observations lead us to conjecture that the tantalizing Tc enhancement may be associated with naturally occurring chemical interfaces and may thus provide a new paradigm in the search for superconductors with higher Tc.

  10. Electronic Raman scattering as a function of doping in high-{Tc} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kendziora, C. [Naval Research Lab., Washington, DC (United States); Kelley, R.J.; Onellion, M. [Univ. of Wisconsin, Madison, WI (United States). Physics Dept.

    1996-12-31

    The authors report the results of Raman scattering from the electronic continuum in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} (Bi 2212) and Ti{sub 2}Ba{sub 2}CuO{sub 6+{delta}} (Tl 2201) high temperature superconductors with variations in the oxygen content, {delta}. Below {Tc}, a peak develops in the Raman continuum associated with the opening of a superconducting gap, {Delta}(k). By selecting the polarizations of incident and scattered light, they are sensitive to possible anisotropy of the gap within the a-b plane. Near optimal doping, both materials show gap anisotropy, with 2{Delta}/k{sub B}{Tc} values of 7.2 (B{sub 1g}) vs. 5.8 (A{sub 1g}) in Tl 2202 and 8.5 (B{sub 1g}) vs. 6.2 (A{sub 1g}) in Bi 2212. In contrast, both show an isotropic gap at much lower energy shifts when the carrier concentration is raised: 2{Delta}/k{sub B}{Tc} = 3.9 (5.5) for Tl 2201 (Bi 2212) with {Tc} = 37K (57K). The authors compare the observed spectra with calculations based on order parameters with d-wave as well as isotropic s-wave symmetry and conclude that raising the doping level reduces the gap anisotropy to near zero.

  11. Phase diagram and isotopic effect in high-Tc pnictide superconductors

    Science.gov (United States)

    Chen, Xianhui

    2010-03-01

    We will talk about the discovery of superconductivity with Tc higher than 40 K in Fe-based superconductors SmFeAsO1-xF. Tc higher than McMillan limit of 39 K definitely proves pnictide superconductors high-Tc superconductivity^1,2. In this talk, we present the transport properties: resistivity, Hall coefficient and transport properties under high magnetic field. These results suggest a quantum phase transition around x=0.14 in SmFeAsO1-xFx system. A electronic phase diagram is proposed, and coexistence of superconductivity and spin-density-wave is observed in Sm-1111 and Ba-122 system. We discuss the effect of isotopic effect on TC and TSDW in SmFeAsO1-xFx and Ba1-xKxFe2As2 systems. Our results show that oxygen isotope effect on TC and TSDW is very little, while the iron isotope exponent is about 0.35. Surprisingly, the iron isotope exchange shows the same effect on SDW transition as on superconductivity. Our results indicate that electron-phonon interaction plays some role in the superconducting mechanism, but simple electron-phonon coupling mechanism seems to be rather unlikely because a strong magnon-phonon coupling is included^3. 1. Chen, X. H. et al. Nature 453, 761-762 (2008). 2. Liu, R. H. et al. Phys. Rev. Lett. 101, 087001 (2008). 3. R. H. Liu et al., Nature 459, 64-67(2009).

  12. High Tc Superconducting Materials for Strong Current Applications: Approach at the First Stage

    Institute of Scientific and Technical Information of China (English)

    JIN Jian-xun

    2007-01-01

    Strong current and large-scale application is the most important prospect of high Tc superconductors (HTS). Practical HTS samples in various forms have been produced with high critical currents operated at economic cryogenic temperatures. Engineering applications of those HTS materials have been studied with various HTS prototype devices. The applicable HTS materials produced in different forms are verified in this paper with regard to their strong current characterizations, and the HTS applications are summarized along with the HTS prototypes made.

  13. Critical currents and superconductivity ferromagnetism coexistence in high-Tc oxides

    CERN Document Server

    Khene, Samir

    2016-01-01

    The book comprises six chapters which deal with the critical currents and the ferromagnetism-superconductivity coexistence in high-Tc oxides. It begins by gathering key data for superconducting state and the fundamental properties of the conventional superconductors, followed by a recap of the basic theories of superconductivity. It then discusses the differences introduced by the structural anisotropy on the Ginzburg-Landau approach and the Lawrence-Doniach model before addressing the dynamics of vortices and the ferromagnetism-superconductivity coexistence in high-Tc oxides, and provides an outline of the pinning phenomena of vortices in these materials, in particular the pinning of vortices by the spins. It elucidates the methods to improve the properties of superconducting materials for industrial applications. This optimization aims at obtaining critical temperatures and densities of critical currents at the maximum level possible. Whereas the primary objective is the basic mechanisms pushing the superco...

  14. On detection of the Fermi edge in in situ grown thin films of high- Tc oxides

    Science.gov (United States)

    Abrecht, M.; Ariosa, D.; Saleh, S. A.; Rast, S.; Margaritondo, G.; Onellion, M.; Pavuna, D.

    2001-11-01

    We discuss our systematic series of experiments on the photoelectric detection of the Fermi edge using a cylindrical mirror analyser on films of high- Tc oxides, grown in situ by pulsed laser ablation. The Fermi edge (comparable to the edge of the reference Ag) is very easily observed even in the two-phase BSCCO-2212 film that exhibits onsets of superconducting transitions, at 85 and 45 K. In contrast, the Fermi edge is weaker and more difficult to observe even in the state-of-the-art, highly epitaxial, monophase YBa 2Cu 3O 7- y (YBCO) and NdBa 2Cu 3O 7- y (NBCO-123) films (both with Tc=92 K). So far we could not detect the Fermi edge in the films of the double-`chain' YBCO-124.

  15. Multi-Channel High-Tc SQUID Detection System for Metallic Contaminants

    Science.gov (United States)

    Kitamura, Yoshihiro; Hatsukade, Yoshimi; Tanaka, Saburo; Ohtani, Takeyoshi; Suzuki, Shuichi

    Finding ultra-small metallic contaminants is a big issue for manufacturers of lithium-ion batteries nowadays. Therefore, we have developed high-Tc SQUID systems for detection of such fine magnetic metallic contaminants. In this paper, we constructed an eight channel high-Tc SQUID gradiometer system for inspection of a sheet electrode of a lithium ion battery with width of about 70 mm. By this system, a small iron ball of about 30 μm in diameter was successfully detected. It is shown that this system has a detectable range of 70 mm in width. These results suggest that the system is a promising tool for the detection of the contaminants in lithium ion batteries.

  16. Kinetic inductance effects in high-Tc microstrip circuits at microwave frequencies

    Science.gov (United States)

    Byrne, D. P.; Kwor, R.; Kalkur, T. S.

    1990-10-01

    This paper describes the fabrication of high-Tc superconducting thin films of BiCaSrCuO and the patterning of these films into integrated microstrip transmission line resonators designed to exhibit the effects of kinetic inductance. Emphasis is given to techniques to fabricate very thin, low-loss dielectric layers on BiCaSrCuO. Microwave S-parameter measurements on these resonators are reported along with functional dependence of tranmission line phase velocity and the characteristic impedance with temperature and microwave power density, especially at temperatures just below Tc. The results are used to infer high-frequency penetration depths and surface resistivities in BiCaSrCuO.

  17. The Study on AC Susceptibility Grained Model for The High-Tc Superconductor Bi-2223

    Science.gov (United States)

    Ozogul, O.

    2010-01-01

    The magnetic properties and the current transport of High-Tc ceramics are governed not only by the nature of diamagnetic grains but also by their interconnections which constitute the superconducting matrix. Such a sintered High-Tc Superconductor has two effects. One is intrinsic to the superconducting grains and the other is characteristic of the coupling between grains. These phenomena have been widely studied in order to understand the mechanisms governing the flux lines dynamic within critical-state models. While the original Bean model of the critical-state only predicts single characteristic in the imaginary part of the fundamental susceptibilities, grained Bean model, where the superconducting grains are immersed in weak superconducting matrix, predicts the typical double peak appear in the imaginary part and double transitions in the real part. The predictions of the grained Bean model for the field and temperature dependencies of the ac magnetic susceptibilities are compared with experimental results.

  18. High Tc superconductivity mechanism controlled by electric dipole correlation and charge correlation

    OpenAIRE

    2008-01-01

    The model is based on a mirror symmetry breaking second order phase transition leading to a pairing between a free charge carriers and a free mirror charge carriers. This approach gives a unified description of low and high Tc superconductivity with a point of view differing from that of BCS theory.The material's crystal structure symmetry is the key to understand the mechanism of pairing by introducing a mirror plane polarization effect in lattice as it is described below.

  19. Scanning instrumentation for measuring magnetic field trapping in high Tc superconductors

    Science.gov (United States)

    Sisk, R. C.; Helton, A. J.

    1993-01-01

    Computerized scanning instrumentation measures and displays trapped magnetic fields across the surface of high Tc superconductors at 77 K. Data are acquired in the form of a raster scan image utilizing stepping motor stages for positioning and a cryogenic Hall probe for magnetic field readout. Flat areas up to 45 mm in diameter are scanned with 0.5-mm resolution and displayed as false color images.

  20. Mechanism for the high Neel temperature in SrTcO_3

    OpenAIRE

    Middey, S.; Nandy, Ashis Kumar; Mahadevan, Priya; Sarma, D. D.

    2011-01-01

    The microscopic origin of the high Neel temperature (T_N) observed experimentally in SrTcO_3 has been examined using a combination of ab-initio electronic structure calculations and mean-field solutions of a multiband Hubbard model. The G-type antiferromagnetic state is found to be robust for a large region of parameter space, with large stabilization energies found, surprisingly, for small values of intraatomic exchange interaction strength as well as large bandwidths. The microscopic origin...

  1. A high-Tc superconductor bolometer on a silicon nitride membrane

    NARCIS (Netherlands)

    Sánchez, S.; Elwenspoek, M.C.; Gui, C.; Nivelle, de M.J.M.E.; Vries, de R.J.; Korte, de P.A.J.; Bruijn, M.P.; Wijnbergen, J.J.; Michalke, W.; Steinbeiss, E.; Heidenblut, T.; Schwierzi, B.

    1997-01-01

    In this paper we describe the design, fabrication and performance of a high-Tc GdBa2Cu3O7-δ superconductor bolometer positioned on a 2×2 mm2, 1 μm thick silicon nitride membrane. The bolometer structure has an effective area of 0.64 mm2, and was grown on a specially developed Silicon-On-Nitride laye

  2. High-spin states in the sup 9 sup 7 Tc nucleus

    CERN Document Server

    Bucurescu, D; Cata-Danil, I; Ivascu, M; Marginean, N; Rusu, C; Stroe, L; Ur, C A; Gadea, A

    2003-01-01

    High-spin states in the sup 9 sup 7 Tc nucleus have been studied by in-beam gamma-ray spectroscopy with the reaction sup 8 sup 2 Se( sup 1 sup 9 F,4n gamma) at 68 MeV incident energy. Excited states have been observed up to about 8 MeV excitation and spin 43/2 Planck constant. The observed level scheme is compared with results of shell model calculations. (orig.)

  3. Inductance measurements in multilevel high Tc step-edge grain boundary SQUIDS

    Science.gov (United States)

    Forrester, M. G.; Davidson, A.; Talvacchio, J.; Gavaler, J. R.; Przybysz, J. X.

    1994-10-01

    Multilevel high Tc SQUIDs, suitable for digital circuit applications, have been fabricated and tested. The devices employ a YBa2Cu3O7-δ (YBCO) ground plane, an epitaxial SrTiO3 insulator, and a YBCO microstrip layer. Junctions are formed by the step-edge grain boundary process, with a ground plane contact for the ``low'' side of each junction, using only isotropic sputtering and milling techniques. Control current is directly injected in a microstrip segment of the SQUID loop, allowing us to measure the microstrip inductance, and thus to infer the magnetic penetration depth of the YBCO. The SQUIDs are operational above 77 K, at which temperature we infer a penetration depth of 350 nm. The temperature dependence of the penetration depth is found to be in reasonable agreement with the Gorter-Casimir form close to Tc.

  4. Shrinkage of magnetosphere observed by TC-1 satellite during the high-speed solar wind stream

    Institute of Scientific and Technical Information of China (English)

    LI LiuYuan; CAO JinBin; ZHOU GuoCheng; YANG JunYing; YAN ChunXiao; ZHANG TieLong; H. REME; I. DANDOURAS; C. M. CARR

    2008-01-01

    During the interval 06:14-07:30 UT on August 24, 2005, since the Earth's magneto-pause was suddenly compressed by the persistent high-speed solar wind stream with the southward component of the interplanetary magnetic field (IMF), the magnetopause moved Inward for about 3.1 RE. Meanwhile, TC-1 satellite shifted from northern plasma sheet to the northern lobe/mantle region, although it kept Inward flying during the Interval 06:00-07:30UT. The shift of TC-1 from the plasma sheet to the lobe/mantle is caused by the simultaneous inward displacements of the plasma sheet and near-Earth lobe/mantle region, and their inward movement velocity is larger than the inward motion velocity of TC-1. The Joint inward dis-placements of the magnetopause, the lobe/mantle region and the plasma sheet indicate that the whole magnetosphere shrinks inward due to the magnetospheric compression by the high-speed solar wind stream, and the magnetospheric ions are attached to the magnetic field lines (i.e. 'frozen' in magnetic field) and move inward in the shrinking process of magnetosphere. The large shrinkage of magne-tosphere indicates that the near-Earth magnetotail compression caused by the strong solar wind dynamic pressure is much larger than its thickening caused by the southward component of the IMF, and the locations of magnetospheric regions with different plasmas vary remarkably with the variation of the solar wind dynamic pressure.

  5. Extended abstracts of the 12th JAERI workshop on high-Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hojou, Kiichi; Okayasu, Satoru; Sasase, Masato [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ishida, Takekazu [Osaka Prefectual Univ., Sakai (JP)] (eds.)

    2001-03-01

    This workshop was held on December 7-8, 2000 at JAERI (Tokai). The research group at JAERI shares a responsibility for material modification of high-Tc superconductors by irradiation in 'the multi-core project II of the high temperature superconducting material research' organized by STA (Science and Technology Agency) of Japan. This report contains the extended abstracts of workshop presentations covering basic theories, various experimental results and material improvement studies of the superconductivity by high energy ion irradiation. The twelve presentations of the workshop were devoted to a mini symposium where the direct observations of vortices were discussed in view of the various sophisticated techniques. (author)

  6. Effect of high density electropulsing treatment on formability of TC4 titanium alloy sheet

    Institute of Scientific and Technical Information of China (English)

    SONG Hui; WANG Zhong-jin; GAO Tie-jun

    2007-01-01

    An annealed TC4 titanium alloy sheet was treated by high density electropulsing (Jmax=(5.09-5.26)×103A/mm2, tp=110 μs) under ambient conditions. The effect of electropulsing treatment(EPT) on the plastic deformation behavior of TC4 titanium alloy sheet was studied using uniaxial tension tests. The experimental results indicate that electropulsing treatment significantly changes the mechanical properties of sheet metal: the uniform elongation is increased by 35%, the yield stress is decreased by 19.8% and the yield to tensile ratio is decreased by 17.6%. It is of significant meaning to improve the formability of TC4 titanium alloy sheet. The optical microscope and scanning electron microscope(SEM) were used to examine the changes of the microstructure and the fracture morphology before and after the electropulsing treatment. It is found that recrystallization occurs in the sheet metal and dimples in fracture surface are large and deep after the electropulsing treatment. The research results show that the electropulsing treatment is an effective method to improve the formability of titanium alloy sheets.

  7. Direct angle resolved photoemission spectroscopy and superconductivity of strained high-Tc films

    Science.gov (United States)

    Pavuna, Davor; Ariosa, Daniel; Cloetta, Dominique; Cancellieri, Claudia; Abrecht, Mike

    2008-02-01

    Since 1997 we systematically perform direct angle resolved photoemission spectroscopy (ARPES) on in-situ grown thin (<30 nm) cuprate films. Specifically, we probe low-energy electronic structure and properties of high-T_{c} superconductors (HTSC) under different degrees of epitaxial ({compressive vs. tensile}) strain. In overdoped and underdoped in-plane compressed (the strain is induced by the choice of substrate) ≈15 nm thin La_{2-x}Sr_{x}CuO_{4} (LSCO) films we almost double T_{c} to 40 K, from 20 K and 24 K, respectively. Yet the Fermi surface (FS) remains essentially two-dimensional. In contrast, ARPES data under {tensile} strain exhibit the dispersion that is three-dimensional, yet T_{c} drastically decreases. It seems that the in-plane compressive strain tends to push the apical oxygen far away from the CuO_{2} plane, enhances the two-dimensional character of the dispersion and increases T_{c}, while the tensile strain acts in the opposite direction and the resulting dispersion is three-dimensional. We have established the shape of the FS for both cases, and all our data are consistent with other ongoing studies, like EXAFS. As the actual lattice of cuprates is like a `Napoleon-cake', i.e. rigid CuO_{2 } planes alternating with softer `reservoir', that distort differently under strain, our data rule out all oversimplified two-dimensional (rigid lattice) mean field models. The work is still in progress on optimized La-doped Bi-2201 films with enhanced T_{c}.

  8. A novel phthalimide derivative, TC11, has preclinical effects on high-risk myeloma cells and osteoclasts.

    Directory of Open Access Journals (Sweden)

    Maiko Matsushita

    Full Text Available Despite the recent advances in the treatment of multiple myeloma (MM, MM patients with high-risk cytogenetic changes such as t(4;14 translocation or deletion of chromosome 17 still have extremely poor prognoses. With the goal of helping these high-risk MM patients, we previously developed a novel phthalimide derivative, TC11. Here we report the further characterization of TC11 including anti-myeloma effects in vitro and in vivo, a pharmacokinetic study in mice, and anti-osteoclastogenic activity. Intraperitoneal injections of TC11 significantly delayed the growth of subcutaneous tumors in human myeloma-bearing SCID mice. Immunohistochemical analyses showed that TC11 induced apoptosis of MM cells in vivo. In the pharmacokinetic analyses, the Cmax was 2.1 μM at 1 h after the injection of TC11, with 1.2 h as the half-life. TC11 significantly inhibited the differentiation and function of tartrate-resistant acid phosphatase (TRAP-positive multinucleated osteoclasts in mouse osteoclast cultures using M-CSF and RANKL. We also revealed that TC11 induced the apoptosis of myeloma cells accompanied by α-tubulin fragmentation. In addition, TC11 and lenalidomide, another phthalimide derivative, directly bound to nucleophosmin 1 (NPM1, whose role in MM is unknown. Thus, through multiple molecular interactions, TC11 is a potentially effective drug for high-risk MM patients with bone lesions. The present results suggest the possibility of the further development of novel thalidomide derivatives by drug designing.

  9. High 99mTc-DPD myocardial uptake in a patient with apolipoprotein AI-related amyloidotic cardiomyopathy.

    Science.gov (United States)

    Quarta, Candida Cristina; Obici, Laura; Guidalotti, Pier Luigi; Pieroni, Maurizio; Longhi, Simone; Perlini, Stefano; Verga, Laura; Merlini, Giampaolo; Rapezzi, Claudio

    2013-03-01

    Amyloidotic cardiomyopathy is still a widely underdiagnosed condition that usually requires endomyocardial biopsy (EMB) for a definite diagnosis. 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (99mTc-DPD) has proven highly sensitive for detecting amyloidotic cardiomyopathy due to transthyretin-related amyloid deposition. Herein we report the first description of the (99mTc-DPD scintigraphy profile in a patient with suspected amyloidotic cardiomyopathy and a final EMB- and genetically-proven diagnosis of familial apolipoprotein AI amyloidosis due to Leu174Ser variant.

  10. Iron-based superconductors: A new family to find the origin of high Tc superconductivity

    Institute of Scientific and Technical Information of China (English)

    Dao-xin Yao

    2011-01-01

    Since the discovery of iron-based superconductors in 2008 [1],a new tide of study on high Tc superconductors spreads worldwide quickly.After a few years' intensive study,many new compounds of iron-based superconductors have been found and their properties have been disclosed.The great achievement is attributed to the modern experimental techniques,fast developing numerical methods and improved theories during the study of cuprate superconductors or more generally strongly correlated electron systems.For instance,the Fermi surface,band structure and superconducting gap for a new compound could be measured quickly by modern ARPES technique [2].

  11. The gravity-induced phase shift detected by high-Tc Josephson junctions

    Institute of Scientific and Technical Information of China (English)

    HE Jian-e

    2007-01-01

    We derive from the Kaluza-Klein theory a formula for the gravity-induced phase shift around a circuit loop,which amounts to the order of 10-6 We propose experiments to detect this phase shift by using the high-Tc d-wave Josephson junction,which is included in a cuprate superconductor circuit loop.By rotating the loop around the horizontal axis,the gravity-induced phase shift can be detected as a frequency shift.These settings can also be used in turn to determine the gravitational constant.This method will be sensitive and accurate.

  12. Shrinkage of magnetosphere observed by TC-1 satellite during the high-speed solar wind stream

    Institute of Scientific and Technical Information of China (English)

    H.; RME; I.; DANDOURAS; C.; M.; CARR

    2008-01-01

    During the interval 06:14―07:30 UT on August 24, 2005, since the Earth’s magneto- pause was suddenly compressed by the persistent high-speed solar wind stream with the southward component of the interplanetary magnetic field (IMF), the magnetopause moved inward for about 3.1 RE. Meanwhile, TC-1 satellite shifted from northern plasma sheet to the northern lobe/mantle region, although it kept inward flying during the interval 06:00―07:30UT. The shift of TC-1 from the plasma sheet to the lobe/mantle is caused by the simultaneous inward displacements of the plasma sheet and near-Earth lobe/mantle region, and their inward movement velocity is larger than the inward motion velocity of TC-1. The joint inward dis-placements of the magnetopause, the lobe/mantle region and the plasma sheet indicate that the whole magnetosphere shrinks inward due to the magnetospheric compression by the high-speed solar wind stream, and the magnetospheric ions are attached to the magnetic field lines (i.e. ‘frozen’ in magnetic field) and move inward in the shrinking process of magnetosphere. The large shrinkage of magne-tosphere indicates that the near-Earth magnetotail compression caused by the strong solar wind dynamic pressure is much larger than its thickening caused by the southward component of the IMF, and the locations of magnetospheric regions with different plasmas vary remarkably with the variation of the solar wind dynamic pressure.

  13. Defect mediated magnetic interaction and high Tc ferromagnetism in Co doped ZnO nanoparticles.

    Science.gov (United States)

    Pal, Bappaditya; Giri, P K

    2011-10-01

    Structural, optical and magnetic studies have been carried out for the Co-doped ZnO nanoparticles (NPs). ZnO NPs are doped with 3% and 5% Co using ball milling and ferromagnetism (FM) is studied at room temperature and above. A high Curie temperature (Tc) has been observed from the Co doped ZnO NPs. X-ray diffraction and high resolution transmission electron microscopy analysis confirm the absence of metallic Co clusters or any other phase different from würtzite-type ZnO. UV-visible absorption and photoluminescence studies on the doped samples show change in band structure and oxygen vacancy defects, respectively. Micro-Raman studies of doped samples shows defect related additional strong bands at 547 and 574 cm(-1) confirming the presence of oxygen vacancy defects in ZnO lattice. The field dependence of magnetization (M-H curve) measured at room temperature exhibits the clear M-H loop with saturation magnetization and coercive field of the order of 4-6 emu/g and 260 G, respectively. Temperature dependence of magnetization measurement shows sharp ferromagnetic to paramagnetic transition with a high Tc = 791 K for 3% Co doped ZnO NPs. Ferromagnetic ordering is interpreted in terms of overlapping of polarons mediated through oxygen vacancy defects based on the bound magnetic polaron (BMP) model. We show that the observed FM data fits well with the BMP model involving localised carriers and magnetic cations.

  14. Thermophysical properties of Almahata Sitta meteorites (asteroid 2008 TC3) for high-fidelity entry modeling

    Science.gov (United States)

    Loehle, Stefan; Jenniskens, Peter; Böhrk, Hannah; Bauer, Thomas; Elsäßer, Henning; Sears, Derek W.; Zolensky, Michael E.; Shaddad, Muawia H.

    2017-02-01

    Asteroid 2008 TC3 was characterized in a unique manner prior to impacting Earth's atmosphere, making its October 7, 2008, impact a suitable field test for or validating the application of high-fidelity re-entry modeling to asteroid entry. The accurate modeling of the behavior of 2008 TC3 during its entry in Earth's atmosphere requires detailed information about the thermophysical properties of the asteroid's meteoritic materials at temperatures ranging from room temperature up to the point of ablation (T 1400 K). Here, we present measurements of the thermophysical properties up to these temperatures (in a 1 atm. pressure of argon) for two samples of the Almahata Sitta meteorites from asteroid 2008 TC3: a thick flat-faced ureilite suitably shaped for emissivity measurements and a thin flat-faced EL6 enstatite chondrite suitable for diffusivity measurements. Heat capacity was determined from the elemental composition and density from a 3-D laser scan of the sample. We find that the thermal conductivity of the enstatite chondrite material decreases more gradually as a function of temperature than expected, while the emissivity of the ureilitic material decreases at a rate of 9.5 × 10-5 K-1 above 770 K. The entry scenario is the result of the actual flight path being the boundary to the load the meteorite will be affected with when entering. An accurate heat load prediction depends on the thermophysical properties. Finally, based on these data, the breakup can be calculated accurately leading to a risk assessment for ground damage.

  15. Internal resonance of an elastic body levitated above high-Tc superconducting bulks

    Energy Technology Data Exchange (ETDEWEB)

    Kokuzawa, T; Toshihiko, S; Yoshizawa, M, E-mail: sugiura@mech.keio.ac.j [Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama (Japan)

    2010-06-01

    In high-Tc superconducting magnetic levitation systems, levitated bodies can keep stable levitation with no contact and no control and thus their damping is very small. Thanks to these features, their applications to various apparatus are expected. However, on account of their small damping, the nonlinearity of electromagnetic levitation force can give notable effects upon motion of the levitated bodies. Therefore this nonlinearity must be taken into account to accurately analyze the dynamical behavior of the levitated bodies. Structures of such a levitated body can show elastic deformation if the large electromagnetic force acts on it. Therefore, we need to deal with the model as an elastic body. As mentioned above, nonlinear characteristics easily appear in this elastic vibration on account of the small damping. Especially when the ratio of the natural frequencies of the eigenmodes is integer, internal resonance can occur. This nonlinear resonance is derived from nonlinear interactions among the eigenmodes of the elastic levitated body. This kind of internal resonance of an elastic body appearing in high-Tc superconducting levitation systems has not been studied so far. This research especially deals with internal resonance of a beam supported at both its ends by electromagnetic forces acting on permanent magnets. The governing equation with the nonlinear boundary conditions for the dynamics of a levitated beam has been derived. Numerical results show internal resonance of the 1st mode and the 3rd mode. Experimental results are qualitatively in good agreement with numerical ones.

  16. Operation of high- Tc SFQ devices at near liquid nitrogen temperature

    Science.gov (United States)

    Kim, Y. H.; Kang, J. H.; Lee, J. M.; Hahn, T. S.; Choi, S. S.; Park, S. J.

    1997-02-01

    As the operating temperature of the SFQ logic circuits gets higher by using high- Tc superconductors, the effect of noise on switching a Josephson junction to the voltage state becomes more important. In this paper, we report our work on high- Tc SFQ RS flip-flop which was made with YBCO thin film deposited on a SrTiO 3 bi-crystal. The circuit operated correctly at 71 K over the 200 computer-generated clock cycles without making errors, where a reset or a set operation was made over one clock cycle. Good agreement between the measured data and the calculation based on the thermal activation theory was obtained. The effective noise temperature used to fit the data was much higher than the physical temperature. This could be due to the instrument noise. Improvement in the measurement set-up might reduce the effective noise temperature. Also our measurement results indicate that the elevation of the operating temperature near the liquid nitrogen temperature may not affect the margin of the circuit.

  17. Optimization of HighTc Josephson nanojunctions by Monte Carlo simulations

    Science.gov (United States)

    Sirena, M.; Bergeal, N.; Lesueur, J.; Faini, G.; Bernard, R.; Briatico, J.; Crete, D.

    2007-03-01

    The fabrication of YBCO JJ by ion damage is the best method that allows closed packed JJ series within the nanoscale and that could operate at high temperature. However, the strong variation of the JJ's critical current with temperature (T) and the increase of dispersion for high irradiation dose are still important issues for several applications. Reproducible HTc JJ have been produced combining electron beam lithography and ion beam irradiation, whose characteristics can be adjusted on a wide range of T. To further improve the homogeneity of planar JJ and optimize their behaviour, we have studied its lateral ion damage distribution (LDD) for different ions and incident energies using Monte Carlo simulations. The LDD was used to calculate the transition temperature (Tc') of the irradiated zone and its resistance as a function of T. Dispersion in the irradiation mask's size was introduced as the source of the JJ's in-homogeneity. The simulations results reproduce quite well the observed dispersion of the irradiated JJ. A linear behaviour of the JJ's Tc' dispersion with basically the LDD width was found, independent of the incident ions mass, its energy, the films thickness, etc. By choosing the appropriate parameters is possible to increase the JJ homogeneity, reducing the LDD width.

  18. Josephson junction between two high Tc superconductors with arbitrary transparency of interface

    Directory of Open Access Journals (Sweden)

    GhR Rashedi

    2010-03-01

    Full Text Available In this paper, a dc Josephson junction between two singlet superconductors (d-wave and s-wave with arbitrary reflection coefficient has been investigated theoretically. For the case of high Tc superconductors, the c-axes are parallel to an interface with finite transparency and their ab-planes have a mis-orientation. The physics of potential barrier will be demonstrated by a transparency coefficient via which the tunneling will occur. We have solved the nonlocal Eilenberger equations and obtained the corresponding and suitable Green functions analytically. Then, using the obtained Green functions, the current-phase diagrams have been calculated. The effect of the potential barrier and mis-orientation on the currents is studied analytically and numerically. It is observed that, the current phase relations are totally different from the case of ideal transparent Josephson junctions between d-wave superconductors and two s-wave superconductors. This apparatus can be used to demonstrate d-wave order parameter in high Tc superconductors.

  19. Levitation performance of the magnetized bulk high- Tc superconducting magnet with different trapped fields

    Science.gov (United States)

    Liu, W.; Wang, J. S.; Liao, X. L.; Zheng, S. J.; Ma, G. T.; Zheng, J.; Wang, S. Y.

    2011-03-01

    To a high- Tc superconducting (HTS) maglev system which needs large levitation force density, the magnetized bulk high- Tc superconductor (HTSC) magnet is a good candidate because it can supply additional repulsive or attractive force above a permanent magnet guideway (PMG). Because the induced supercurrent within a magnetized bulk HTSC is the key parameter for the levitation performance, and it is sensitive to the magnetizing process and field, so the magnetized bulk HTSC magnets with different magnetizing processes had various levitation performances, not only the force magnitude, but also its force relaxation characteristics. Furthermore, the distribution and configuration of the induced supercurrent are also important factor to decide the levitation performance, especially the force relaxation characteristics. This article experimentally investigates the influences of different magnetizing processes and trapped fields on the levitation performance of a magnetized bulk HTSC magnet with smaller size than the magnetic inter-pole distance of PMG, and the obtained results are qualitatively analyzed by the Critical State Model. The test results and analyses of this article are useful for the suitable choice and optimal design of magnetized bulk HTSC magnets.

  20. Vibration reduction using autoparametric resonance in a high-Tc superconducting levitation system

    Science.gov (United States)

    Yamasaki, Hiroshi; Takazakura, Toyoki; Sakaguchi, Ryunosuke; Sugiura, Toshihiko

    2014-05-01

    High-Tc superconducting levitation systems have very small damping and enable stable levitation without control. Therefore, they can be applied to various kinds of application. However, there are some problems that small damping produces large vibration and nonlinearity of magnetic force can generate complicated phenomena. Accordingly, analysis of these phenomena and reduction of vibration occurring in the system are important. In this study, we examined reduction of vibration without using any absorbers, but utilizing autoparametric resonance caused by nonlinear coupling between vertical oscillation and horizontal oscillation. We conducted numerical analysis and experiments in order to investigate motions of a rigid bar levitated by the electromagnetic force from high-Tc superconductors. As a result, if the ratio of the natural frequency of vertical oscillation and that of horizontal oscillation is two to one, the vertical oscillation decreases while the horizontal oscillation is excited. Thus, it was confirmed that the amplitude of a primary resonance can be reduced by occurrence of autoparametric resonance without using any absorbers.

  1. Imaging of local temperature distributions in mesas of high-Tc superconducting terahertz sources

    Science.gov (United States)

    Tsujimoto, M.; Kambara, H.; Maeda, Y.; Yoshioka, Y.; Nakagawa, Y.; Kakeya, I.

    2014-12-01

    Stacks of intrinsic Josephson junctions in high-Tc superconductors are a promising source of intense, continuous, and monochromatic terahertz waves. In this paer, we establish a fluorescence-based temperature imaging system to directly image the surface temperature on a Bi2Sr2CaCu2O8+δ mesa sample. Intense terahertz emissions are observed in both high- and low-bias regimes, where the mesa voltage satisfies the cavity resonance condition. In the high- bias regime, the temperature distributions are shown to be inhomogeneous with a considerable temperature rise. In contrast, in the low-bias regime, the distributions are rather uniform and the local temperature is close to the bath temperature over the entire sample.

  2. High-Tc superconductivity in nanostructured NaxWO3-y: Sol-gel route

    Science.gov (United States)

    Aliev, Ali

    2009-03-01

    Tungsten trioxide, WO3-y infiltrated into various nanoporous matrix structures such as carbon inverse opal, carbon nanotubes paper, or platinum sponge and then intercalated with alkaline ions (Li^+, Na^+) exhibits a pronounced diamagnetic onset in ZFC magnetization in a wide range of temperatures, 125-132 K. Resistivity measurements show non zero jump and intensive fluctuations of electrical resistance below observed transition points. The observed magnetic and electrical anomalies in nanostructured tungsten bronzes (LixWO3-y, NaxWO3-y) suggest the possibility of localized non-percolated superconductivity. The direct evidence of polaron formation from temperature dependence of EPR and photoemission spectra and formation of bipolarons in weakly reduced to WO3-y, with 3-y typically in the order of 2.95 suggest bipolarons mechanism of a Bose-Einstein condensation of trapped electron pairs in doped WO3-y. On the other hand the strong lattice instabilities in 2D systems like layered cuprates and tungsten bronzes place the upper limit on Tc. Than, the percolative self-organized mechanism on the metal/insulator interface like Na/WO3 and NaWO3/nanostructured matrix can facilitate the high Tc obtained in sodium bronzes infiltrated into inverted carbon opal or carbon nanotube matricies.

  3. Superconducing gap anisotropy vs. doping level in high-Tc cuprates

    Science.gov (United States)

    Kendziora, C.; Kelley, R. J.; Onellion, M.

    1996-03-01

    We report the results of Raman scattering from the electronic continuum in Bi_2Sr_2CaCu_2O_8+δ (Bi 2212) and Tl_2Ba_2CuO_6+δ (Tl 2201) high temperature superconductors with variations in the oxygen content, δ. Below T_c, a peak develops in the Raman continuum associated with the opening of a superconducting gap, Δ(k). By selecting the polarizations of incident and scattered light, we are sensitive to possible anisotropy of the gap within the a-b plane. Near optimal doping, both materials show gap anisotropy, with 2Δ/k_BTc values of 7.2 (B_1g) vs. 5.8 (A_1g) in Tl 2201 and 8.5 (B_1g) vs. 6.2 (A_1g) in Bi 2212. In contrast, both show an isotropic gap at much lower energy shifts when the carrier concentration is raised: 2Δ/k_BTc = 3.9 (5.5) for Tl 2201 (Bi 2212) with Tc = 37K (57K). We compare the observed spectra with calculations based on order parameters with d-wave as well as isotropic s-wave symmetry and conclude that raising the doping level reduces the gap anisotropy to near zero.

  4. Infrared spectra of the high- Tc TlBaCaCuO superconductors

    Science.gov (United States)

    Yanru, Ren; Hanpeng, Liu; Mingzhu, Lin; Qingyun, Tu; Lihua, Sang; Zhenjin, Lin; Xianren, Meng; Zhenxing, Liu

    1988-12-01

    The TlBaCaCuO superconductors with zero resistance at temperatures in the range of 100-123 K have been sintered by solid state reactions. Electron microscopy and X-ray diffraction studies reveal that they are multiphased, containing both Tl 2Ba 2CaCu 2O 8 and Tl 2Ba 2Ca 2Cu 3O 10 superconducting phases. Infrared spectra have been measured at room temperature for the multiphase samples. The spectra display structures at ∼590 cm -1 ( P1) and ∼530 cm -1 ( P2) which seem characteristic to Cu-O stretching modes. The difference Δ P between P1 and P1 has been found to be related to the superconducting transition temperature. Smaller Δ P corresponds to a higher Tc. The electron-like excitation of∼0.1 eV and the phonon-like structure at ∼850 cm -1 are also found to be important for high Tc.

  5. Hilbert Spectral Analysis of THz Radiation Sources by High-Tc Josephson Detectors

    Science.gov (United States)

    Divin, Yuriy; Lyatti, Matvey; Poppe, Ulrich

    A Hilbert spectrum analyzer was developed and characterized with monochromatic radiation sources at the frequency range from 30 GHz to 1 THz. The analyzer was based on a high-Tc frequency-selective Josephson detector and cooled to temperatures of 60-80K by a Stirling cryocooler. The instrumental function of the spectrum analyzer was shown to be of Lorentz type and within accuracy up to 0.1% without any harmonic and subharmonic contributions. Spectral characterization of THz sources, based on frequency multiplication of input microwave radiation by Schottky diodes, was demonstrated for input frequencies from 10 to 20 GHz with a total scanning time as low as 50 ms per scan. The developed Hilbert spectrum analyzer might be considered as a compact and high-speed substitute of conventional Fourier spectrometers, which are used for characterization of THz radiation sources in combination with liquid-helium-cooled silicon bolometers.

  6. Separation of charge-order and magnetic QCPs in heavy fermions and high Tc cuprates

    Science.gov (United States)

    Harrison, Neil

    2010-03-01

    The Fermi surface topology of high temperature superconductors inferred from magnetic quantum oscillation measurements provides clues for the origin of unconventional pairing thus previously not accessed by other spectroscopy techniques. While the overdoped regime of the high Tc phase diagram has a large Fermi surface consistent with bandstructure calculations, the underdoped regime of YBa2Cu2O6+x is found to be composed of small pockets. There is considerable debate as to whether the small observed ``pocket'' is hole-like or electron-like- whether the Fermi surface is best described by a t-J model or a conventional band folding picture- whether or not a Fermi liquid description applies- or- whether bilayer coupling splits the degeneracy of the observed pockets. We (myself and collaborators) have now collected an extensive body of experimental data that brings this debate to rest, but raises new questions about the nature of itinerant magnetism in underdoped high Tc cuprates. Quantum oscillation measurements are performed on multiple samples in magnetic fields extending to 85 T, temperatures between 30 mK (dilution fridge in dc fields to 45 T) and 18 K, over a range of hole dopings and with samples rotated in-situ about multiple axes with respect to the magnetic field. We perform a topographical map of the Fermi surface, enabling the in-plane shape of one of the pockets to be determined- imposing stringent constraints on the origin of the Fermi surface. While quantum oscillations measurements are consistent with a topological Fermi surface change associated with magnetism near optimal doping, they also point to a secondary instability deep within the underdoped regime beneath a high Tc superconducting sub-dome. An steep upturn in the quasiparticle effective mass is observed on underdoping, suggestive of a quantum critical point near x= 0.46 separating the metallic regime (composed of small pockets) from a more underdoped insulating charge-ordered regime (earlier

  7. Development and characterization of highly polymorphic long TC repeat microsatellite markers for genetic analysis of peanut

    Directory of Open Access Journals (Sweden)

    Macedo Selma E

    2012-02-01

    Full Text Available Abstract Background Peanut (Arachis hypogaea L. is a crop of economic and social importance, mainly in tropical areas, and developing countries. Its molecular breeding has been hindered by a shortage of polymorphic genetic markers due to a very narrow genetic base. Microsatellites (SSRs are markers of choice in peanut because they are co-dominant, highly transferrable between species and easily applicable in the allotetraploid genome. In spite of substantial effort over the last few years by a number of research groups, the number of SSRs that are polymorphic for A. hypogaea is still limiting for routine application, creating the demand for the discovery of more markers polymorphic within cultivated germplasm. Findings A plasmid genomic library enriched for TC/AG repeats was constructed and 1401 clones sequenced. From the sequences obtained 146 primer pairs flanking mostly TC microsatellites were developed. The average number of repeat motifs amplified was 23. These 146 markers were characterized on 22 genotypes of cultivated peanut. In total 78 of the markers were polymorphic within cultivated germplasm. Most of those 78 markers were highly informative with an average of 5.4 alleles per locus being amplified. Average gene diversity index (GD was 0.6, and 66 markers showed a GD of more than 0.5. Genetic relationship analysis was performed and corroborated the current taxonomical classification of A. hypogaea subspecies and varieties. Conclusions The microsatellite markers described here are a useful resource for genetics and genomics in Arachis. In particular, the 66 markers that are highly polymorphic in cultivated peanut are a significant step towards routine genetic mapping and marker-assisted selection for the crop.

  8. 99mTc-labeled HYNIC-DAPI causes plasmid DNA damage with high efficiency.

    Science.gov (United States)

    Kotzerke, Joerg; Punzet, Robert; Runge, Roswitha; Ferl, Sandra; Oehme, Liane; Wunderlich, Gerd; Freudenberg, Robert

    2014-01-01

    (99m)Tc is the standard radionuclide used for nuclear medicine imaging. In addition to gamma irradiation, (99m)Tc emits low-energy Auger and conversion electrons that deposit their energy within nanometers of the decay site. To study the potential for DNA damage, direct DNA binding is required. Plasmid DNA enables the investigation of the unprotected interactions between molecules and DNA that result in single-strand breaks (SSBs) or double-strand breaks (DSBs); the resulting DNA fragments can be separated by gel electrophoresis and quantified by fluorescent staining. This study aimed to compare the plasmid DNA damage potential of a (99m)Tc-labeled HYNIC-DAPI compound with that of (99m)Tc pertechnetate ((99m)TcO4(-)). pUC19 plasmid DNA was irradiated for 2 or 24 hours. Direct and radical-induced DNA damage were evaluated in the presence or absence of the radical scavenger DMSO. For both compounds, an increase in applied activity enhanced plasmid DNA damage, which was evidenced by an increase in the open circular and linear DNA fractions and a reduction in the supercoiled DNA fraction. The number of SSBs elicited by 99mTc-HYNIC-DAPI (1.03) was twice that caused by (99m)TcO4(-) (0.51), and the number of DSBs increased fivefold in the (99m)Tc-HYNIC-DAPI-treated sample compared with the (99m)TcO4(-) treated sample (0.02 to 0.10). In the presence of DMSO, the numbers of SSBs and DSBs decreased to 0.03 and 0.00, respectively, in the (99m)TcO4(-) treated samples, whereas the numbers of SSBs and DSBs were slightly reduced to 0.95 and 0.06, respectively, in the (99m)Tc-HYNIC-DAPI-treated samples. These results indicated that (99m)Tc-HYNIC-DAPI induced SSBs and DSBs via a direct interaction of the (99m)Tc-labeled compound with DNA. In contrast to these results, (99m)TcO4(-) induced SSBs via radical formation, and DSBs were formed by two nearby SSBs. The biological effectiveness of (99m)Tc-HYNIC-DAPI increased by approximately 4-fold in terms of inducing SSBs and by

  9. 99mTc-labeled HYNIC-DAPI causes plasmid DNA damage with high efficiency.

    Directory of Open Access Journals (Sweden)

    Joerg Kotzerke

    Full Text Available (99mTc is the standard radionuclide used for nuclear medicine imaging. In addition to gamma irradiation, (99mTc emits low-energy Auger and conversion electrons that deposit their energy within nanometers of the decay site. To study the potential for DNA damage, direct DNA binding is required. Plasmid DNA enables the investigation of the unprotected interactions between molecules and DNA that result in single-strand breaks (SSBs or double-strand breaks (DSBs; the resulting DNA fragments can be separated by gel electrophoresis and quantified by fluorescent staining. This study aimed to compare the plasmid DNA damage potential of a (99mTc-labeled HYNIC-DAPI compound with that of (99mTc pertechnetate ((99mTcO4(-. pUC19 plasmid DNA was irradiated for 2 or 24 hours. Direct and radical-induced DNA damage were evaluated in the presence or absence of the radical scavenger DMSO. For both compounds, an increase in applied activity enhanced plasmid DNA damage, which was evidenced by an increase in the open circular and linear DNA fractions and a reduction in the supercoiled DNA fraction. The number of SSBs elicited by 99mTc-HYNIC-DAPI (1.03 was twice that caused by (99mTcO4(- (0.51, and the number of DSBs increased fivefold in the (99mTc-HYNIC-DAPI-treated sample compared with the (99mTcO4(- treated sample (0.02 to 0.10. In the presence of DMSO, the numbers of SSBs and DSBs decreased to 0.03 and 0.00, respectively, in the (99mTcO4(- treated samples, whereas the numbers of SSBs and DSBs were slightly reduced to 0.95 and 0.06, respectively, in the (99mTc-HYNIC-DAPI-treated samples. These results indicated that (99mTc-HYNIC-DAPI induced SSBs and DSBs via a direct interaction of the (99mTc-labeled compound with DNA. In contrast to these results, (99mTcO4(- induced SSBs via radical formation, and DSBs were formed by two nearby SSBs. The biological effectiveness of (99mTc-HYNIC-DAPI increased by approximately 4-fold in terms of inducing SSBs and by approximately

  10. Manipulation of magnetic carriers for drug delivery using pulsed-current high Tc superconductors

    Science.gov (United States)

    Cha, Yung; Chen, Lihua; Askew, Thomas; Veal, Boyd; Hull, John

    2007-04-01

    An innovative method of manipulating magnetic carriers is proposed, and its feasibility for drug delivery and therapy is demonstrated experimentally. The proposed method employs pulsed-field solenoid coils with high-critical- temperature ( Tc) superconductor inserts. Pulsed current is used to magnetize and de-magnetize the superconductor insert. The proposed method was demonstrated to be able to (1) move magnetic particles, ranging in size from a few millimeters to 10 μm, with strong enough forces over a substantial distance, (2) hold the particles at a designated position as long as needed, and (3) reverse the processes and retrieve the particles. We further demonstrated that magnetic particles can be manipulated in a stationary environment, in water flow, and in simulated blood (water/glycerol mixture) flow.

  11. Quantum nucleation of Minkowski spacetime from nothing in hyperbolic metamaterials based on high Tc superconductors

    CERN Document Server

    Smolyaninov, Igor I

    2013-01-01

    We demonstrate that high Tc superconductors exhibit hyperbolic metamaterial behavior in the far infrared and THz frequency ranges. In the THz range the hyperbolic behavior occurs only in the normal state, while no propagating modes exist in the superconducting state. Wave equation, which describes propagation of extraordinary light inside a hyperbolic metamaterial exhibits 2+1 dimensional Lorentz symmetry. The role of time in the corresponding effective 3D Minkowski spacetime is played by the spatial coordinate aligned perpendicular to the copper oxide layers. Such superconductor-based hyperbolic metamaterials exhibit a quantum phase transition at T=0, in which the effective Minkowski spacetime arise in the mixed state of the superconductor at some critical value of external magnetic field. Nucleation of Minkowski spacetime occurs via formation of quantized Abrikosov vortices, so that these vortices play the role of Minkowski spacetime quanta. Thus, the described system may be used as an experimental model of...

  12. Finding new superconductors: the spin-fluctuation gateway to high Tc and possible room temperature superconductivity.

    Science.gov (United States)

    Pines, David

    2013-10-24

    We propose an experiment-based strategy for finding new high transition temperature superconductors that is based on the well-established spin fluctuation magnetic gateway to superconductivity in which the attractive quasiparticle interaction needed for superconductivity comes from their coupling to dynamical spin fluctuations originating in the proximity of the material to an antiferromagnetic state. We show how lessons learned by combining the results of almost three decades of intensive experimental and theoretical study of the cuprates with those found in the decade-long study of a strikingly similar family of unconventional heavy electron superconductors, the 115 materials, can prove helpful in carrying out that search. We conclude that, since Tc in these materials scales approximately with the strength of the interaction, J, between the nearest neighbor local moments in their parent antiferromagnetic state, there may not be a magnetic ceiling that would prevent one from discovering a room temperature superconductor.

  13. Advanced nanoscopic studies in magneto-electric manganites and high T$_c$ superconductors

    CERN Document Server

    Melo Mendonça, Tânia Manuela; Martins Correia, João Guilherme

    2012-05-01

    Technological advances in materials synthesis and the development of new experimental techniques have created a wealth of information with remarkable implications for understanding the macroscopic properties of systems with strongly correlated electronic properties. These advances allowed the observation of a wide range of exotic phenomena such as high T$_c$ superconductivity, colossal magneto-resistance or, more recently, multiferroic behavior, which are known to be strongly dependent on the nanoscale phenomenology. In fact, several experimental and theoretical studies demonstrated that strongly correlated electron systems are not homogeneous at a local scale due to simultaneously active spin, charge, lattice and/or orbital interactions. Consequently, these systems show nanoscale chemical and electronic disorder, which lead to a rich variety of macroscopic properties. It is under this scope that the nuclear hyperfine techniques are introduced, being particularly useful to infer the local lattice structure, e...

  14. Quantum topological transition in hyperbolic metamaterials based on high Tc superconductors.

    Science.gov (United States)

    Smolyaninov, Igor I

    2014-07-30

    Hyperbolic metamaterials are known to exhibit a transition in the topology of the photon iso-frequency surface from a closed ellipsoid to an open hyperboloid, resulting in a considerable increase of the photonic density of states. This topological transition may also be described as a change of metric signature of the effective optical space. Here we demonstrate that high Tc superconductors exhibit hyperbolic metamaterial behavior in the far infrared and THz frequency ranges. In the THz range the hyperbolic behavior occurs only in the normal state, while no propagating photon modes exist in the superconducting state. Thus, a quantum topological transition may be observed for THz photons at zero temperature as a function of the external magnetic field, in which the effective Minkowski spacetime arises in the mixed state of the superconductor at some critical value of the external magnetic field. Nucleation of effective Minkowski spacetime occurs via the formation of quantized Abrikosov vortices.

  15. Electron Spin Pairing and the Phase Diagram of High-Tc Superconductors

    Institute of Scientific and Technical Information of China (English)

    GUO Wei; HAN Ru-Shan

    2001-01-01

    The origin of the instability of the normal state of electrons in the superconducting copper oxides is shown by the K-J model, in which the superexchange (K) between local moments and the Kondo exchange ( J) between electron and local moment are considered. The suppression of superexchange via impurity doping may induce effective spin coupling between electrons and triplet pairing (S = 1, Sz = 0). The spin pairing theory explains the phase diagram of high-To superconductors, especially the superconducting transition temperature Tc, the pseudogap temperature T* and the magnetic crossover temperature Tn as a function of the doped hole concentration. The universal expression for the empirical law of the superconducting transition temperature is derived from the theory.

  16. High- T_c superconducting thin film/GaAs MESFET hybrid microwave oscillator

    Institute of Scientific and Technical Information of China (English)

    金飚兵; 康琳; 伍瑞新; 张健羽; 程其恒; 吴培亨; 经东; 焦刚; 邵凯; 蒋明明; 张家宗; 孙敏松; 王蕴仪; 周岳亮; 吕惠宾; 许世发; 何萌; 王小平; 杨秉川; 卢剑; 张其邵

    1997-01-01

    A high- Tc superconducting (HTSC) thin film/GaAs MESFET hybrid microwave oscillator operated at 10 6 GHz has been designed, fabricated and characterized. Microstrip line structures were used throughout the circuit with superconducting thin film YBaiCuiO7 8(YBCO) as the conductor material. The YBCO thin films were deposited on 15 mm×10 mm×0. 5 mm LaAlO3 substrates. The oscillator was common-source, series feedback type using a GaAs-MESFET (NE72084) as the active device and a superconducting microstrip resonator as the frequency stabilizing element. By improving the unloaded quality factor Q0 of the superconducting microstrip resonator and adjusting the coupling coefficient between the resonator and the gate of the MESFET, the phase noise of the oscillator was decreased At 77 K, the phase noise of the oscillator at 10 kHz offset from carrier was - 87 dBc/Hz.

  17. High-Tc planar SQUID gradiometer for eddy current non-destructive evaluation

    Institute of Scientific and Technical Information of China (English)

    Zhang Ming-Jian; Lang Pei-Lin; Peng Zhi-Hui; Chen Ying-Fei; Chen Ke; Zheng Dong-Ning

    2006-01-01

    This paper reports the fabrication and test of a high-Tc SQUID planar gradiometer which is patterned from YBCO thin film deposited on a SrTiOs bicrystal substrate. The measurement of noise spectrum at 77K shows that the white noise at 200 Hz is about 1×10-4Φ0/Hz. The minimal magnetic gradient is measured and the results suggest that the minimal magnetic gradient is 94 pT/m. The planar gradiometer is used in non-destructive evaluation (NDE) experiments to detect the artifacts in conducting aluminium plates by performing eddy current testing in an unshielded environment. The effect of the exciting coil dimension on the NDE results is investigated. By mapping out the induced field distribution, flaws about 10mm below the plate surface can be clearly identified.

  18. Electrical properties of Y-Ba-Na-Cu-O high Tc superconductors thin films

    Energy Technology Data Exchange (ETDEWEB)

    Verdyan, A. (Center for Theoretical Education Holon (Israel) Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel-Aviv Univ. (Israel)); Lapsker, I. (Center for Theoretical Education Holon (Israel) Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel-Aviv Univ. (Israel)); Azoulay, J. (Center for Theoretical Education Holon (Israel) Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel-Aviv Univ. (Israel))

    1993-04-20

    Y-Ba-Na-Cu-O high Tc superconductors thin films deposited on MgO substrate by resistive evaporation technique were found to have improved electrical properties as compared to pure Y-Ba-Cu-O thin films similarly prepared. A simple conventional inexpensive vacuum system housing a single resistively tungsten heated source was used for the deposition. Pulverized mixture of Y, BaF[sub 2], NaF and Cu in the appropriate atomic proportion was evaporated onto the substrates whose temperature was held constant at 400 C during the evaporation. In situ heat treatment has been carried out at 700 C under oxygen partial pressure of 7 pa. The films thus obtained were found to have the normal superconductors orthorhombic phase at room temperature without any further ex situ heat treatment. The films were characterized and analyzed by X-ray diffraction auger election spectroscopy and four point dc electrical measurements. (orig.)

  19. Electrical properties of Y-Ba-Na-Cu-O high Tc superconductors thin films

    Science.gov (United States)

    Verdyan, A.; Lapsker, I.; Azoulay, J.; Sackler, Raymond; Sackler, Beverly

    1993-04-01

    Y-Ba-Na-Cu-O high Tc superconductors thin films deposited on MgO substrate by resistive evaporation technique were found to have improved electrical properties as compared to pure Y-Ba-Cu-O thin films similarly prepared. A simple conventional inexpensive vacuum system housing a single resistively tungsten heated source was used for the deposition. Pulverized mixture of Y, BaF 2, NaF and Cu in the appropriate atomic proportion was evaporated onto the substrates whose temperature was held constant at 400°C during the evaporation. In situ heat treatment has been carried out at 700°C under oxygen partial pressure of 7 pa. The films thus obtained were found to have the normal superconductors orthorhombic phase at room temperature without any further ex situ heat treatment. The films were characterized and analyzed by x-ray diffraction auger electron spectroscopy and four point dc electrical measurements.

  20. Features in Quasi-particle Excitations and Tunnelling Spectra due to Coupling to Spin Fluctuations in High-Tc Cuprates

    Institute of Scientific and Technical Information of China (English)

    赵力; 李建新; 龚昌德; 赵柏儒

    2002-01-01

    In a self-consistent mean-field treatment of the two-dimensional t - t' - J model, we theoretically examine thecoupling of in-plane quasi-particles to the antiferromagnetic spin fluctuations in high-Tc superconductors, whichrenormalizes the fermionic self-energy. We reproduce the characteristic peak,lip-hump structure observed notonly in angle-resolved photoemission spectroscopy, but also in superconductor-insulator-normal metal junctionsand scanning tunnelling microscopy experiments. We consider the evolution of this structure with doping. Itis shown that this kind of coupling can account for many anomalous properties of high-Tc superconductors insuperconducting states.

  1. Enhancing electric-field control of ferromagnetism through nanoscale engineering of high-Tc MnxGe1-x nanomesh

    Science.gov (United States)

    Nie, Tianxiao; Tang, Jianshi; Kou, Xufeng; Gen, Yin; Lee, Shengwei; Zhu, Xiaodan; He, Qinglin; Chang, Li-Te; Murata, Koichi; Fan, Yabin; Wang, Kang L.

    2016-10-01

    Voltage control of magnetism in ferromagnetic semiconductor has emerged as an appealing solution to significantly reduce the power dissipation and variability beyond current CMOS technology. However, it has been proven to be very challenging to achieve a candidate with high Curie temperature (Tc), controllable ferromagnetism and easy integration with current Si technology. Here we report the effective electric-field control of both ferromagnetism and magnetoresistance in unique MnxGe1-x nanomeshes fabricated by nanosphere lithography, in which a Tc above 400 K is demonstrated as a result of size/quantum confinement. Furthermore, by adjusting Mn doping concentration, extremely giant magnetoresistance is realized from ~8,000% at 30 K to 75% at 300 K at 4 T, which arises from a geometrically enhanced magnetoresistance effect of the unique mesh structure. Our results may provide a paradigm for fundamentally understanding the high Tc in ferromagnetic semiconductor nanostructure and realizing electric-field control of magnetoresistance for future spintronic applications.

  2. New Horizontal Merger Guidelines Indicate Greater Scrutiny of High Tech and Pharmaceutical Transactions

    OpenAIRE

    Janet McDavid; Eric Stock

    2010-01-01

    It also indicates greater Agency scrutiny of such transactions in industries characterized by differentiated products and high levels of R&D spendingâ۠such as the high tech and pharmaceutical industries. Janet McDavid & Eric Stock (Hogan Lovells)

  3. Unconventional charge order in a co-doped high-Tc superconductor.

    Science.gov (United States)

    Pelc, D; Vučković, M; Grafe, H-J; Baek, S-H; Požek, M

    2016-01-01

    Charge-stripe order has recently been established as an important aspect of cuprate high-Tc superconductors. However, owing to the complex interplay between competing phases and the influence of disorder, it is unclear how it emerges from the parent high-temperature state. Here we report on the discovery of an unconventional ordered phase between charge-stripe order and (pseudogapped) metal in the cuprate La1.8-xEu0.2SrxCuO4. We use three complementary experiments-nuclear quadrupole resonance, nonlinear conductivity and specific heat-to demonstrate that the order appears through a sharp phase transition and exists in a dome-shaped region of the phase diagram. Our results imply that the new phase is a state, which preserves translational symmetry: a charge nematic. We thus resolve the process of charge-stripe development in cuprates, show that this nematic phase is distinct from high-temperature pseudogap and establish a link with other strongly correlated electronic materials with prominent nematic order.

  4. Unconventional charge order in a co-doped high-Tc superconductor

    Science.gov (United States)

    Pelc, D.; Vučković, M.; Grafe, H.-J.; Baek, S.-H.; Požek, M.

    2016-09-01

    Charge-stripe order has recently been established as an important aspect of cuprate high-Tc superconductors. However, owing to the complex interplay between competing phases and the influence of disorder, it is unclear how it emerges from the parent high-temperature state. Here we report on the discovery of an unconventional ordered phase between charge-stripe order and (pseudogapped) metal in the cuprate La1.8-xEu0.2SrxCuO4. We use three complementary experiments--nuclear quadrupole resonance, nonlinear conductivity and specific heat--to demonstrate that the order appears through a sharp phase transition and exists in a dome-shaped region of the phase diagram. Our results imply that the new phase is a state, which preserves translational symmetry: a charge nematic. We thus resolve the process of charge-stripe development in cuprates, show that this nematic phase is distinct from high-temperature pseudogap and establish a link with other strongly correlated electronic materials with prominent nematic order.

  5. Construction and Tests of a High-Tc SQUID-Based Heart Scanner Cooled by Small Stirling Cryocoolers

    NARCIS (Netherlands)

    Blom, C.J.H.A.; Brake, ter H.J.M.; Holland, H.J.; Rijpma, A.P.; Rogalla, H.; Ross, R.G.

    1999-01-01

    A heart scanner that can be equipped with up to 25 high-Tc SQUID magnetometers was designed at the University of Twente. In this design the mechanical cooler interference is reduced by operating two coolers in counterphase. The magnetic cooler interference diminished by positioning the coolers and t

  6. Construction and tests of a high-Tc SQUID-based heart scanner cooled by small Stirling cryocoolers

    NARCIS (Netherlands)

    Blom, C.J.H.A.; ter Brake, Hermanus J.M.; Holland, Herman J.; Rijpma, A.P.; Rogalla, Horst; Ross, R.G.

    1999-01-01

    A heart scanner that can be equipped with up to 25 high-Tc SQUID magnetometers was designed at the University of Twente. In this design the mechanical cooler interference is reduced by operating two coolers in counterphase. The magnetic cooler interference diminished by positioning the coolers and

  7. Fabrications aspects of microwave devices, including ramp-type high-Tc Josephson junctions and log-periodic antenna's

    NARCIS (Netherlands)

    Terpstra, D.; Rijnders, A.J.H.M.; Roesthuis, F.J.G.; Blank, D.H.A.; Gerritsma, G.J.; Rogalla, H.

    1993-01-01

    We describe the development of high-Tc Josephson junction devices for applications at millimeter wave frequencies. These devices consist of ramp type YBCO/PBCO/YBCO Josephson junctions that are equipped with a noble metal log-periodic antenna. Growth conditions of all layers, as well as etching, cle

  8. Normal-state nodal electronic structure in underdoped high-Tc copper oxides.

    Science.gov (United States)

    Sebastian, Suchitra E; Harrison, N; Balakirev, F F; Altarawneh, M M; Goddard, P A; Liang, Ruixing; Bonn, D A; Hardy, W N; Lonzarich, G G

    2014-07-03

    An outstanding problem in the field of high-transition-temperature (high-Tc) superconductivity is the identification of the normal state out of which superconductivity emerges in the mysterious underdoped regime. The normal state uncomplicated by thermal fluctuations can be studied using applied magnetic fields that are sufficiently strong to suppress long-range superconductivity at low temperatures. Proposals in which the normal ground state is characterized by small Fermi surface pockets that exist in the absence of symmetry breaking have been superseded by models based on the existence of a superlattice that breaks the translational symmetry of the underlying lattice. Recently, a charge superlattice model that positions a small electron-like Fermi pocket in the vicinity of the nodes (where the superconducting gap is minimum) has been proposed as a replacement for the prevalent superlattice models that position the Fermi pocket in the vicinity of the pseudogap at the antinodes (where the superconducting gap is maximum). Although some ingredients of symmetry breaking have been recently revealed by crystallographic studies, their relevance to the electronic structure remains unresolved. Here we report angle-resolved quantum oscillation measurements in the underdoped copper oxide YBa2Cu3O6 + x. These measurements reveal a normal ground state comprising electron-like Fermi surface pockets located in the vicinity of the nodes, and also point to an underlying superlattice structure of low frequency and long wavelength with features in common with the charge order identified recently by complementary spectroscopic techniques.

  9. Development of 1.3GHz high-Tc rf SQUID

    Institute of Scientific and Technical Information of China (English)

    Liu Xin-Yuan; Xie Fei-Xiang; Meng Shu-Chao; Dai Yuan-Dong; Li Zhuang-Zhi; Ma Ping; Yang Tao; Nie Rui-Juan; Wang Fu-Ren

    2004-01-01

    @@ A new high-Tc (HTc) rf SQUID working at around 1.3GHz has been developed to avoid electromagnetic interference such as growing mobile communication jamming. This new system works in a frequency range from 1.23 to 1.42GHz (centred at 1.3GHz), which is not occupied by commercial communication. The sensor used in the 1.3GHz rf SQUID is made of a HTc coplanar superconducting resonator and a large-area HTc superconducting film concentrator. We have achieved in the 1.3GHz HTc rf SQUID system a minimal flux noise of 2.5×10-5φ0/√Hz and a magnetic field sensitivity of 38fT/√Hz in white noise range, respectively. The effective area of the concentrator fabricated on a 15×15mm2 substrate is 1.35mm2. It is shown that the 1.3GHz rf SQUID system has a high field sensitivity. Design and implementation of 1.3GHz HTc rf SQUID offers a promising direction of rf SQUID development for higher working frequency ranges.

  10. Growth of High TcYBaCuO Thin Films by Metalorganic Chemical Vapor Deposition

    Science.gov (United States)

    Kirlin, Peter S.; Binder, R.; Gardiner, R.; Brown, Duncan W.

    1990-03-01

    Thin films of YBa2Cu3O7-x were grown on MgO(100) by metalorganic chemical vapor deposition (MOCVD). Low pressure growth studies were carried out between 400 and 600°C using metal β-diketonate complexes as source reagents for Y, Ba, and Cu. As-deposited films were amorphous and a two stage annealing protocol was used in which fluorine was first removed in a Ar/H20 stream between 700 and 850°C, followed by calcination in flowing oxygen between 500 and 950°C. Scanning electron microscopy, X-ray diffraction and energy dispersive analysis indicate that good compositional and dimensional uniformity could be achieved. The temperature of the oxygen annealing step was shown to have a dramatic impact on the physical and electrical properties of the YBa2Cu307-x thin films. Annealing temperatures exceeding 910°C gave large crystallites and semiconducting resistivity above Tc; annealing temperatures below 910°C yielded films with metallic conductivity whose density and superconducting transition varied inversely with maximum annealing temperature. Optimized deposition/annealing protocols yielded films with a preferred c-axis orientation, R273/R100 ratios of 2, onsets as high as 94K and zero resistance exceeding 90K.

  11. Report on neutron beam utilization and study of high Tc superconductors at NRI

    Energy Technology Data Exchange (ETDEWEB)

    Vuong Huu Tan [Nuclear Physics Dept., Nuclear Research Inst. (NRI), Dalat (Viet Nam)

    1998-10-01

    Utilization of reactor neutron beams at NRI for research and applications up to November 1996 had been presented at the last Workshop in Jakarta (25-28 Nov., 1996). This paper describes new research and applications carried out at Nuclear Physics Department of NRI after that time. They consist of neutron beam developments, neutron activation cross section measurements for waste disposal assessment and in-vivo prompt gamma neutron activation analysis for Cd determination in organs. After the last Sub-Workshop on Neutron Scattering in Serpong (21-23 Nov., 1996), we were accepted to participate in the Regional Program on Study of High Tc Superconductors with the topic `The mechanism of Pb and Sb dopant role on superconductivity of 2223 phase of Bi-Sr-Ca-Cu-O system`. Indeed, this study has begun at NRI only since August, 1997 due to the problem of materials. The study has been carried out in collaboration with the Hanoi State University (Superconductors Department) where experts and equipment for superconductors research have been considered as the best ones in Vietnam. Primary results in this study are presented in this workshop. (author)

  12. A universal order underlying the pseudogap regime of the underdoped high Tc cuprates

    Science.gov (United States)

    Harrison, Neil

    2014-03-01

    A major achievement in condensed matter physics in the last quarter century has been a step towards the understanding of the unconventional d-wave superconducting state in the copper-oxide materials. Surprisingly, the normal state out of which the superconducting state emerges remains a mystery at low charge carrier densities, i.e., in the underdoped regime. This regime is of particular interest because it is characterised by an unusual momentum dependent energy pseudogap in the excitation spectrum that has defied explanation and is key to a full understanding of the unconventional d-wave superconducting state. I will present new quantum oscillation experimental results within the pseudogap regime of the high Tc superconductors YBa2Cu3O6+x and YBa2Cu4O8 which now extend up to the optimally-doped regime. These data reveal the evolution of the Fermi surface approaching the putative quantum critical point under the superconducting dome. A comprehensive angle-resolved study of the Fermi surface enables us to unambiguously identify a specific form of order that accounts for the observed quantum oscillations as well as other spectroscopic, transport and thermodynamic probes within the pseudogap regime. The author would like to thank B. Ramshaw, S. Sebastian, F. Balakirev, C. Mielke, M. Altarawneh, P. Goddard, S. Sabok, B. Babrowski, D. Bonn, W. Hardy, R. Liang and G. Lonzarich. This work was supported by the DOE BES ``Science of 100 tesla'' project and by the NSF and Florida State.

  13. Direct angle resolved photoelectron spectroscopy (DARPES) on high-Tc films: doping, strains, Fermi surface topology and superconductivity

    Science.gov (United States)

    Pavuna, D.; Ariosa, D.; Cancellieri, C.; Cloetta, D.; Abrecht, M.

    2008-03-01

    Since 1997 we systematically perform Direct ARPES ( = DARPES) on in-situ grown, non-cleaved, ultra-thin (<25nm) cuprate films. Specifically, we probe low energy electronic structure and properties of high-Tc films under different degree of epitaxial (compressive vs tensile) strain. In overdoped in-plane compressed La2-xSrxCuO4 (LSCO) thin films we double Tc from 20K to 40K, yet the Fermi surface (FS) remains essentially 2-dimensional (2D). In contrast, tensile strained films show 3-dimensional (3D) dispersion, while Tc is drastically reduced. It seems that the in-plane compressive strain tends to push the apical oxygen far away from the CuO2 plane, enhances the 2D character of the dispersion and increases Tc, while the tensile strain seems to act exactly in the opposite direction and the resulting dispersion is 3D. We have the FS topology for both cases. As the actual lattice of cuprates is 'Napoleon-cake' -like i.e. rigid CuO2 planes alternate with softer 'reservoir' (that strains distort differently) our results tend to rule out 2D rigid lattice mean field models. Finally, we briefly discuss recent successful determination of the FS topology from the observed wavevector quantization by DARPES in cuprate films thinner than 18 units cells (<24nm). Such an approach is of broader interest as it can be extended to other similar confined (ultra-thin) functional oxide systems.

  14. Anomalous open-circuit voltage from a high-Tc superconducting dynamo

    Science.gov (United States)

    Bumby, C. W.; Jiang, Zhenan; Storey, J. G.; Pantoja, A. E.; Badcock, R. A.

    2016-03-01

    We report on the behavior of a high-Tc superconducting (HTS) homopolar dynamo which outputs a DC open-circuit voltage when the stator is in the superconducting state, but behaves as a conventional AC alternator when the stator is in the normal state. We observe that this time-averaged DC voltage arises from a change in the shape of the AC voltage waveform that is obtained from a normal conducting stator. The measured DC voltage is proportional to frequency, and decreases with increasing flux gap between the rotor magnet and the HTS stator wire. We observe that the DC output voltage decreases to zero at large flux gaps, although small differences between the normal-conducting and superconducting waveforms are still observed, which we attribute to screening currents in the HTS stator wire. Importantly, the normalised pulse shape is found to be a function of the rotor position angle only. Based on these observations, we suggest that the origin of this unexpected DC effect can be explained by a model first proposed by Giaever, which considers the impact of time-varying circulating eddy currents within the HTS stator wire. Such circulating currents form a superconducting shunt path which "short-circuits" the high field region directly beneath the rotor magnet, at those points in the cycle when the rotor magnet partially overlaps the superconducting stator wire. This reduces the output voltage from the device during these periods of the rotor cycle, leading to partial rectification of the output voltage waveform and hence the emergence of a time-averaged DC voltage.

  15. 99mTc-Labeled HYNIC-DAPI Causes Plasmid DNA Damage with High Efficiency

    OpenAIRE

    Joerg Kotzerke; Robert Punzet; Roswitha Runge; Sandra Ferl; Liane Oehme; Gerd Wunderlich; Robert Freudenberg

    2014-01-01

    (99m)Tc is the standard radionuclide used for nuclear medicine imaging. In addition to gamma irradiation, (99m)Tc emits low-energy Auger and conversion electrons that deposit their energy within nanometers of the decay site. To study the potential for DNA damage, direct DNA binding is required. Plasmid DNA enables the investigation of the unprotected interactions between molecules and DNA that result in single-strand breaks (SSBs) or double-strand breaks (DSBs); the resulting DNA fragments ca...

  16. Emergent high-Tc ferroelectric ordering of strongly correlated and frustrated protons in a heteroepitaxial ice film

    Science.gov (United States)

    Sugimoto, Toshiki; Aiga, Norihiro; Otsuki, Yuji; Watanabe, Kazuya; Matsumoto, Yoshiyasu

    2016-11-01

    Materials containing strong correlation and frustration have the potential to respond to external perturbations in an unusual way. In the case of common water ice, protons in the hydrogen-bond network are strongly correlated and highly frustrated under Pauling's ice rules. At low temperature, the strongly correlated protons lose ergodicity, and little is understood about the cooperative thermodynamic and electric response to external stimuli. Here, using a model platinum substrate, we demonstrate emergent high-Tc ferroelectric proton ordering in a heteroepitaxial ice film. Such proton ordering is thermodynamically stable and has an extremely high critical temperature of ~175 K. We found that anisotropy and protolysis driven by the electrostatistics at the heterointerface are key factors in stimulating this novel exotic ordering in the many-body correlated proton system. The significant increase in Tc due to the heterointerface suggests the ubiquity of ferroelectric ice in nature--specifically, in space and the polar stratosphere.

  17. Doping-Induced Change of Optical Properties in Underdoped High-Tc Superconductors.

    Science.gov (United States)

    Liu, H. L.; Tanner, D. B.; Berger, H.; Forro, L.; Margaritondo, G.

    1997-03-01

    We report on ab-plane reflectivity measurements in underdoped single crystals of Bi_2Sr_2CaCu_2O_8. A generalized Drude analysis of the optical conductivity shows that the frequency-dependent scattering rate, 1/τ(ω,T), of two moderately underdoped samples (with Tc = 85, 80 K) displays similar structure at low frequencies as temperature is reduced. This threshold structure in the scattering rate is enhanced and moves to higher frequencies over the whole temperature range in two heavily underdoped crystals (with Tc = 40, 35 K). Alternatively, a two-component description has been used to fit the optical data. The Drude relaxation rate 1/τ(T) varies linearly with temperature and decreases dramatically below Tc in all underdoped materials. Interestingly, the magnitude of both elastic scattering and inelastic scattering of Ni doped crystal is large compared to other samples. We also found that superconducting Tc scales linearly with the condensated superfluid density, consistent with the results of muon-spin-rotation experiments. supported by NSF-9403894

  18. Mott insulator to high Tc superconductor via pressure: resonating valence bond theory and prediction of new systems.

    Science.gov (United States)

    Baskaran, G

    2003-05-16

    Mott insulator superconductor transition, via pressure and no external doping, is studied in orbitally nondegenerate spin-1 / 2 systems. It is presented as another resonating valence bond route to high T(c) superconductivity. We propose a "strong coupling" hypothesis that views long range Coulomb force driven first order Mott transition as a self-doping process that also preserves superexchange on the metal side. We present a two-species t-J model where conserved N0 doubly occupied (e(-)) sites and N0 empty sites (e(+)) hop in the background of N-2N(0) singly occupied (neutral) sites in a lattice of N sites. An equivalence to the regular t-J model is made. Some old and new systems are predicted to be candidates for pressure-induced high T(c) superconductivity.

  19. Influence of coupling parameter on current-voltage characteristics of intrinsic Josephson junctions in high- Tc superconductors

    Science.gov (United States)

    Shukrinov, Yu. M.; Mahfouzi, F.

    2006-02-01

    We study the current-voltage characteristics of intrinsic Josephson junctions in high-Tc superconductors by numerical calculations and in framework of capacitively coupled Josephson junctions model we obtain the total number of branches. The influence of the coupling parameter α on the current-voltage characteristics at fixed parameter β (β2 = 1/βc, where βc is McCumber parameter) and the influence of α on β-dependence of the current-voltage characteristics are investigated. We obtain the α-dependence of the branch's slopes and branch's endpoints. The presented results show new features of the coupling effect on the scheme of hysteresis jumps in current-voltage characteristics of intrinsic Josephson junctions in high-Tc superconductors.

  20. In situ fabrication of high-Tc Y-Ba-Cu-O thin film by resistive evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Azoulay, J. (Centre for Technological Education, Holon (Israel) Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv Univ. (Israel))

    1992-11-20

    We have recently used a simple conventional oil-pumped vacuum system equipped with a resistively heated boat for in situ fabrication of Y-Ba-Cu-O high Tc superconductivity phase thin films at a relatively low substrate temperature. A well-ground mixture of yttrium, BaF[sub 2] and copper, weighed in the atomic proportion to yield a stoichiometric YBa[sub 2]Cu[sub 3]O[sub 7-[delta

  1. Convective high-speed flow and field-aligned high-speed flows explored by TC-1

    Institute of Scientific and Technical Information of China (English)

    ZHANG LingQian; LIU ZhenXing; MA ZhiWei; W.BAUMJOHANN; M.W.DUNLOP4; WANG GuangJun; WANG Xiao; H.REME; C.CARR

    2008-01-01

    From June 1, 2004 to October 31, 2006, a total 465 high-speed flow events are observed by the TC-1 satellite in the near-Earth region (-13 RE < X < -9 RE, |Y|<10 RE, |2|<5 RE). Based on the angle between the flow and the magnetic field, the high-speed flow events are further divided into two types, that is,field-aligned high-speed flow (FAHF) in the plasma sheet boundary and convective bursty bulk flow (BBF) in the center plasma sheet. Among the total 465 high-speed flow events, there are 371 FAHFs,and 94 BBFs. The CHF are mainly concentrated in the plasma sheet, the intersection angle between the flow and the magnetic field is larger, the magnetic field intensity is relatively weak. The FHF are mainly distributed near the boundary layer of the plasma sheet, the intersection angle between the flow and magnetic field is smaller, and the magnetic field intensity is relatively strong. The convective BBFs have an important effect on the substorm.

  2. Oxygen Adsorption-Desorption Behavior and Superconducting Properties of High-Tc Bi(Pb)-Sr-Ca-Cu-O

    Science.gov (United States)

    Miura, Norio; Suzuta, Hiroki; Deshimaru, Yuichi; Shimizu, Youichi; Sakashita, Hirofumi; Yamazoe, Noboru

    1989-07-01

    Temperature-programmed desorption (TPD) chromatograms revealed that a small amount of oxygen was desorbed from high-Tc Bi(Pb)-Sr-Ca-Cu-O (BPSCCO) in the temperature range from ca. 350 to ca. 650°C prior to a steep increase of oxygen desorption in the higher temperature range. The Tc of BPSCCO was significantly lowered with the progress of oxygen desorption especially in the former temperature range, and was restored to the original level when the desorbed oxygen was recovered. With no corresponding changes in X-ray powder diffraction pattern being detected, the oxygen desorbed below ca. 650°C was concluded to have strong relevance to the superconductivity of BPSCCO.

  3. Very high MHC Class IIB diversity without spatial differentiation in the mediterranean population of greater Flamingos.

    Science.gov (United States)

    Gillingham, Mark A F; Béchet, Arnaud; Courtiol, Alexandre; Rendón-Martos, Manuel; Amat, Juan A; Samraoui, Boudjéma; Onmuş, Ortaç; Sommer, Simone; Cézilly, Frank

    2017-02-20

    Selective pressure from pathogens is thought to shape the allelic diversity of major histocompatibility complex (MHC) genes in vertebrates. In particular, both local adaptation to pathogens and gene flow are thought to explain a large part of the intraspecific variation observed in MHC allelic diversity. To date, however, evidence that adaptation to locally prevalent pathogens maintains MHC variation is limited to species with limited dispersal and, hence, reduced gene flow. On the one hand high gene flow can disrupt local adaptation in species with high dispersal rates, on the other hand such species are much more likely to experience spatial variation in pathogen pressure, suggesting that there may be intense pathogen mediated selection pressure operating across breeding sites in panmictic species. Such pathogen mediated selection pressure operating across breeding sites should therefore be sufficient to maintain high MHC diversity in high dispersing species in the absence of local adaptation mechanisms. We used the Greater Flamingo, Phoenicopterus roseus, a long-lived colonial bird showing a homogeneous genetic structure of neutral markers at the scale of the Mediterranean region, to test the prediction that higher MHC allelic diversity with no population structure should occur in large panmictic populations of long-distance dispersing birds than in other resident species. We assessed the level of allelic diversity at the MHC Class IIB exon 2 from 116 individuals born in four different breeding colonies of Greater Flamingo in the Mediterranean region. We found one of the highest allelic diversity (109 alleles, 2 loci) of any non-passerine avian species investigated so far relative to the number of individuals and loci genotyped. There was no evidence of population structure between the four major Mediterranean breeding colonies. Our results suggest that local adaptation at MHC Class IIB in Greater Flamingos is constrained by high gene flow and high MHC diversity

  4. Presentation of test cases TC-2A, TC-2B, TC-2C, TC-2D - Twodimensional, incompressible, wall flows with separation

    DEFF Research Database (Denmark)

    Scheel Larsen, Poul

    1988-01-01

    The four test cases comprise the backfacing step at high Re-number (TC-2A) and low Re-number (TC-2B), a low Re-number boundary layer flow past a thin obstacle, fence-on-wall (TC-2C), and a high Re-number developed channel flow past a squareobstacle (TC-2D). Geometry, test conditions and available...

  5. High T(c) superconductivity in MgB2 by nonadiabatic pairing.

    Science.gov (United States)

    Cappelluti, E; Ciuchi, S; Grimaldi, C; Pietronero, L; Strässler, S

    2002-03-18

    The evidence for the key role of the sigma bands in the electronic properties of MgB2 points to the possibility of nonadiabatic effects in the superconductivity of these materials. These are governed by the small value of the Fermi energy due to the vicinity of the hole doping level to the top of the sigma bands. We show that the nonadiabatic theory leads to a coherent interpretation of T(c) = 39 K and the boron isotope coefficient alphaB = 0.30 without invoking very large couplings and it naturally explains the role of the disorder on T(c). It also leads to various specific predictions for the properties of MgB2 and for the material optimization of these types of compounds.

  6. X-ray MCD Measurements in a high Tc molecular-based magnet

    NARCIS (Netherlands)

    Arrio, M.-A.; Sainctavit, Ph.; Cartier dit Moulin, Ch.; Brouder, Ch.; Groot, F.M.F. de; Mallah, T.; Verdaguer, M.

    1996-01-01

    The molecular based magnet Cs^(I)[Ni^(II)Cr^(III)(CN)6]. 2H2O is a ferromagnet with a Curie temperature Tc = 90 K. Its structure consists of face centred cubic lattice of Ni^(II) ions connected by Cr(CN)6 entities. We have recorded X-ray Magnetic Circular Dichroism (XMCD) at nickel L2,3 edges. It

  7. X-ray MCD Measurements in a high Tc molecular-based magnet

    NARCIS (Netherlands)

    Arrio, M.-A.; Sainctavit, Ph.; Cartier dit Moulin, Ch.; Brouder, Ch.; Groot, F.M.F. de; Mallah, T.; Verdaguer, M.

    2001-01-01

    The molecular based magnet Cs^(I)[Ni^(II)Cr^(III)(CN)6]. 2H2O is a ferromagnet with a Curie temperature Tc = 90 K. Its structure consists of face centred cubic lattice of Ni^(II) ions connected by Cr(CN)6 entities. We have recorded X-ray Magnetic Circular Dichroism (XMCD) at nickel L2,3 edges. It cl

  8. Measurement of Magnetic Moment at the Atomic Scale in a High TC Molecular Based Magnet

    NARCIS (Netherlands)

    Arrio, M.-A.; Sainctavit, Ph.; Cartier dit Moulin, Ch.; Brouder, Ch.; Groot, F.M.F. de; Mallah, T.; Verdaguer, M.

    2001-01-01

    The molecular-based magnet Cs^(I) [Ni^(II) Cr^(III) (CN)6]-2H2O is a ferromagnetic with a Curie temperature TC ) 90 K. Its structure consists of face-centered cubic lattice of Ni^(II) ions connected by Cr(CN)6 entities. We have recorded X-ray magnetic circular dichroism (XMCD) at nickel L2,3 edges.

  9. Unusual isotope effects on the pseudogap in high-Tc cuprate superconductors as support for the BCS-like pairing theory of large polarons above Tc

    Science.gov (United States)

    Dzhumanov, S.; Baimatov, P. J.; Djumanov, Sh. S.

    2015-06-01

    The BCS-like pairing theory is extended to the intermediate coupling regime and to the cases of exotic cuprate superconductors with large and small Fermi surfaces, so as to describe the pairing correlations above Tc , the opening of a pseudogap (PG) at a mean-field temperature T∗ >Tc and the unusual isotope effects on the PG in these materials within the large polaron model and two different BCS-like approaches. We argue that unconventional electron-phonon interactions are responsible for the polaron formation and the separation between temperatures T∗ (the onset of precursor Cooper pairing) and Tc (the onset of the superconducting transition) in exotic cuprate superconductors. Using the extended BCS-like approaches, we calculate the PG formation temperature T∗ , isotope shifts ΔT∗ , oxygen and copper isotope exponents and show that isotope effects on the PG basically depend on strengths of Coulomb and electron-phonon interactions, doping levels and dielectric constants of the cuprates. The new BCS-like pairing theory of polaronic carriers predicts the existence of small and sizable positive oxygen isotope effect and very large negative oxygen and copper isotope effects on the PG in the cuprates with large Fermi surfaces. The calculated results for T∗ , isotope shifts and exponents are compared with experimental data on various cuprate superconductors. For all the considered cases, a good quantitative agreement was found between theory and experimental data. We also predict the existence of small and sizable negative isotope effects on T∗ in deeply underdoped cuprates with small Fermi surfaces. Further, we find that the isotope effects on T∗ (=Tc) in heavily overdoped cuprates just like in some metals are relatively small positive or become even negative.

  10. High- Tc superconductivity due to coexisting wide and narrow bands: A fluctuation exchange study of the Hubbard ladder as a test case

    Science.gov (United States)

    Kuroki, Kazuhiko; Higashida, Takafumi; Arita, Ryotaro

    2005-12-01

    We propose that when the Fermi level lies within a wide band and also lies close to but not within a coexisting narrow band, high- Tc superconductivity may take place due to the large number of interband pair scattering channels and the small renormalization of the quasiparticles. We show using the fluctuation exchange method that this mechanism works for the Hubbard model on a ladder lattice with diagonal hoppings. From this viewpoint, we give a possible explanation for the low Tc for the actual hole-doped ladder compound, and further predict a higher Tc for the case of electron doping.

  11. Mn-stabilized zirconia: from imitation diamonds to a new potential high-Tc ferromagnetic spintronics material.

    Science.gov (United States)

    Ostanin, S; Ernst, A; Sandratskii, L M; Bruno, P; Däne, M; Hughes, I D; Staunton, J B; Hergert, W; Mertig, I; Kudrnovský, J

    2007-01-05

    From the basis of ab initio electronic structure calculations which include the effects of thermally excited magnetic fluctuations, we predict Mn-stabilized cubic zirconia to be ferromagnetic above 500 K. We find this material, which is well known both as an imitation diamond and as a catalyst, to be half-metallic with the majority and minority spin Mn impurity states lying in zirconia's wide gap. The Mn concentration can exceed 40%. The high-Tc ferromagnetism is robust to oxygen vacancy defects and to how the Mn impurities are distributed on the Zr fcc sublattice. We propose this ceramic as a promising future spintronics material.

  12. Higher critical current density achieved in Bi-2223 High-Tc superconductors

    Directory of Open Access Journals (Sweden)

    M.S. Shalaby

    2016-07-01

    Full Text Available Bi2Sr2Ca2Cu3Ox (Bi-2223 were prepared using a solid state reaction method at different sintering times and temperatures. Structural phase identifications have been done using X-Ray analysis and refinement by Reitveld method which proves the coexistence of Bi-2223 and Bi-2212 phases. The critical transition temperature Tc and critical current density Jc values were measured using superconducting quantum interference device magnetometer (SQUID and by the magneto-optics technique. A remarkable rapid decrease to the diamagnetic signal in the magnetization versus temperature M(T at 110 K and Jc around 1.2 × 107 A/m2 at 5 K are confirmed for the Bi-2223 compound.

  13. Dominant aerosol processes during high-pollution episodes over Greater Tokyo

    CERN Document Server

    Sartelet, Karine; Sportisse, Bruno

    2007-01-01

    This paper studies two high-pollution episodes over Greater Tokyo: 9 and 10 December 1999, and 31 July and 1 August 2001. Results obtained with the chemistry-transport model (CTM) Polair3D are compared to measurements of inorganic PM2.5. To understand to which extent the aerosol processes modeled in Polair3D impact simulated inorganic PM2.5, Polair3D is run with different options in the aerosol module, e.g. with/without heterogeneous reactions. To quantify the impact of processes outside the aerosol module, simulations are also done with another CTM (CMAQ). In the winter episode, sulfate is mostly impacted by condensation, coagulation, long-range transport, and deposition to a lesser extent. In the summer episode, the effect of long-range transport largely dominates. The impact of condensation/evaporation is dominant for ammonium, nitrate and chloride in both episodes. However, the impact of the thermodynamic equilibrium assumption is limited. The impact of heterogeneous reactions is large for nitrate and amm...

  14. Rapid sympatry explains greater color pattern divergence in high latitude birds.

    Science.gov (United States)

    Martin, Paul R; Montgomerie, Robert; Lougheed, Stephen C

    2010-02-01

    Latitudinal variation in patterns of evolution has fascinated biologists for over a century, but our understanding of latitudinal differences in evolutionary processes-such as selection and drift-remains limited. Here, we test for, and find, accelerated evolution of color patterns in bird taxa that breed at higher latitudes compared with those breeding in the tropics, analyzing data from seven diverse avian families. Most important, we show that the extent of overlap of species' breeding ranges (degree of sympatry) explains the elevated rate of color pattern evolution at higher latitudes. We suggest that the dynamic shifts in breeding ranges that accompanied climatic changes during the last 3 million years (Milankovitch Oscillations) resulted in more rapid and more frequent secondary contact at high latitudes. We argue that sympatry among diverging clades causes greater divergence of color traits in birds at higher latitudes through sexual, social, or ecological character displacement that accelerate rates of evolution, and through the selective elimination of weakly differentiated lineages that hybridize and fuse in sympatry (differential fusion).

  15. Competing structural ordering tendencies in new high-TC ferromagnetic Fe-Co-based Heusler alloys from ab initio investigations

    Energy Technology Data Exchange (ETDEWEB)

    Dannenberg, Antje; Gruner, Markus; Entel, Peter [Faculty of Physics, University of Duisburg-Essen, 47048 Duisburg (Germany); Wuttig, Manfred [Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742 (United States)

    2011-07-01

    Fe-Co-based Heuslers are candidates for new ferromagnetic shape memory alloys (FSMA) as they promise higher operation temperatures compared with prototype Ni2MnGa. Of interest are also the corresponding binary systems FeZn and Fe3Ga which show a huge magnetostriction. We present results of ab initio and Monte Carlo calculations regarding structural, magnetic, and electronic properties of Fe2CoGa1-xZnx alloys in conventional X2YZ and inverse (XY)XZ Heusler structures. All systems exhibit high Curie temperatures TC. The preference of the cubic inverse structures is believed to originate from the bcc-like environment of two inequivalent Fe atoms and their strong hybridization with the Co- states. Weakening the Co-Fe hybridization by substitution of Ga by Zn reduces this preference and leads to higher TC but simultaneously reduces the miscibility. Despite the strong spin-dependent Fe-Co hybridization we find a localized character of the spin moments. Extraordinary Z-elements like Cu, Ag, and Au or further enhancement of the Zn content induces a martensitic instability also in the inverse structures. Thus, we conclude that it is possible to find new FSMA with rather high Curie temperatures.

  16. Heat treatment of wires on the basis of the high Tc superconductor YBa2Cu3Ox

    Science.gov (United States)

    Müller, P.; Schubert, M.; Rodig, Ch.; Fuchs, G.; Fischer, K.

    1989-08-01

    Ag-sheathed powder-in-tube wires on the basis of the high Tc superconductor YBa2Cu3Ox are produced by a drawing process. After cold working, the wires are not superconducting. By heat treatment at temperatures >900 °C, lattice defects are healed and the contact between the grains is improved. After this heat treatment the wires are slowly cooled in an O2 atmosphere in order to adjust the optimum O2 stoichiometry. The annealing temperature has a strong influence on the attainable critical current density. By annealing a wire with 420 ppm carbon content at 950 °C, jc values of 5020 A/cm2 at 4.2 K and 1130 A/cm2 at 77 K were achieved. Drastically reduced critical current densities in wires with high carbon content demonstrate the importance of a low carbon content for achieving high critical current densities in YBa2Cu3Ox .

  17. TC4钛合金高效磨削加工用环形热管砂轮的研制%Development of Annular Heat Pipe Grinding Wheel for High Efficiency Machining of TC4 Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    赫青山; 傅玉灿; 徐鸿钧; 马可; 陈琛

    2013-01-01

    Workpiece burnout is one of the distressing problems to be solved for the difficult-to-machine material TC4 titanium alloy due to the high grinding temperature caused by excessive grinding heat accumulation in the grinding zone.A new method of cooling the grinding zone by means of heat pipe technology is proposed in this paper.The heat transfer principle of an annular heat pipe grinding wheel(HPGW)was illustrated in the grinding process and an annular HPGW was designed and developed for high efficiency grinding of titanium alloy TC4.The manufacture was performed of annular heat pipe in the wheel consisting of three processes of vacuum pumping,working fluid filling and mechanical sealing.Finally,grinding experiments with different wheels (HPGW and non-HPGW) were carried out to verify the effect of enhancing heat transfer in the grinding zone under the same grinding condition for titanium alloy TC4.The results show that using the HPGW can effectively reduce the grinding temperature and prevent burnout in the grinding process.%针对航空航天高强韧性难加工材料TC4钛合金在磨削加工中存在磨削温度高而导致工件表面烧伤的问题,提出利用热管换热技术冷却磨削弧区的新方法.分析了环形热管砂轮在加工中对磨削弧区的强化换热原理,并设计制作出能够用于磨削加工的环形热管砂轮,同时实现了对砂轮基体内环形管腔的密封、抽真空、精确注液与机械式真空封口.最后,在相同磨削工艺条件下,使用环形热管砂轮和无热管砂轮进行TC4钛合金缓进给深切磨削对比试验,验证了环形热管砂轮对磨削弧区温度的控制效果.试验结果表明:设计制作的环形热管砂轮在TC4钛合金高效磨削过程中可以有效降低磨削温度,避免工件表面出现烧伤.

  18. Phase Diagram and Electronic Properties of High-Tc Superconducting Oxides

    Science.gov (United States)

    Pavuna, Davor

    We firstly briefly summarize some of the most relevant recent results and open questions across rather complex electronic phase diagram of cuprates. We continue with a discussion of results on thin superconducting oxide films grown by laser ablation. Systematic studies show that BSCCO-phases and LSCO-214 exhibit conductor-like Fermi edge, whereas materials containing "chains" (like YBCO-123) are prone to very rapid surface degradation, most likely related to critical oxygen loss at the outermost layers. Recently, direct ARPES dispersion measurements on in-situ grown, strained 10UC thin LSCO-214 films (Tc = 44 K) have shown the band crossing of Fermi level well before the Brillouin zone boundary. This is in contrast to the flat band observed in unstrained single crystals — and to the band flattening predicted by band calculations for in-plane compressive strain. In spite of density of states reduction near the Fermi level, the critical temperature increases in strained films with respect to unstrained crystals; this poses further challenge to HTSC theory.

  19. Analysis of Magnetic Critical Fields in Iron-Based SmFeAsO0.85 HIGH-Tc Superconductor

    Science.gov (United States)

    Ahmad, Dawood; Song, Tae Kwon; Park, In Suk; Kim, G. C.; Ren, Zhi-An; Kim, Y. C.

    The magnetic properties of the newly discovered iron-oxypnictide SmFeAsO0.85 high-Tc superconductor with a Tc of around 55 K were investigated. Bulk SmFeAsO0.85 was prepared by a method for high-pressure synthesis. The lower critical field Hc1 was estimated from the magnetization at low fields; Hc1(0) was measured to be 212 Oe. A linear temperature dependence instead of saturation at low temperatures in Hc1(T) revealed unconventional superconductivity with a nodal gap structure in our SmFeAsO0.85 superconductor. The results showed that the well-known secondary peak in the temperature dependence of the critical current density Jc is absent in the SmFeAsO0.85 high-Tc superconductor. The irreversibility line Birr was fitted well by the power law dependence (1 - T/Tc)n with n ~ 1.5. This is indicative of the flux creep phenomena in the SmFeAsO0.85 high-Tc superconductor. In addition, within the range of measurement temperatures in this study, no crossover was observed in the temperature dependence of the irreversibility line Birr which may be due to low anisotropy in our SmFeAsO0.85 superconductor.

  20. Greater increases in temperature extremes in low versus high income countries

    Science.gov (United States)

    Herold, Nicholas; Alexander, Lisa; Green, Donna; Donat, Markus

    2017-03-01

    It is commonly expected that the world’s lowest income countries will face some of the worst impacts of global warming, despite contributing the least to greenhouse gas emissions. Using global atmospheric reanalyses we show that the world’s lowest income countries are already experiencing greater increases in the occurrence of temperature extremes compared to the highest income countries, and have been for over two decades. Not only are low income countries less able to support mitigation and adaptation efforts, but their typically equatorial location predisposes them to lower natural temperature variability and thus greater changes in the occurrence of temperature extremes with global warming. This aspect of global warming is well known but overlooked in current international climate policy agreements and we argue that it is an important factor in reducing inequity due to climate impacts.

  1. Material Specific Rational Design of A1B2C3O7 High-Tc Superconductors without Copper [A, B, C = Cations

    Science.gov (United States)

    Isikaku-Ironkwe, O'paul; Schaffer, Michael J.

    Soon after the discovery of YBa2Cu3O7 with Tc = 93K, a similar structured system with Ag replacing Cu was discovered with a Tc = 50K. Also, the discovery of Ba0 . 6 K0 . 4 BiO3 with Tc = 30K indicated that Cu was not indispensable for high temperature superconductivity (HTSC). Latter, the discoveries of the Pnictide and Chalcogenide high-Tc superconductors confirmed those earlier experimental indications. Using our recently developed Material Specific Characterization Dataset (MSCD) model for analysis and design of superconductors, we have computed many designs that satisfy the MSCD characteristics of YBa2Cu3O7 as a design model. Our design recognizes the valence state characteristics that make YBa2Cu3O6 a semiconductor, while YBa2Cu3O7is a superconductor. Here we present ten material specific rational design examples of potential A1B2C3O7 HTSCs without Cu, using the YBa2Cu3O7 design model. This MSCD design model opens the possibility for search and discovery of high-Tc oxide superconductor systems without copper.

  2. Examination of the peak in dICO/dlnt in weak-linked high Tc superconductors caused by trapped flux

    Science.gov (United States)

    Rezeq, Moh'd.; LeBlanc, M. A. R.

    2007-04-01

    Altshuler et al discovered that dICO/dlnt, the rate of increase of the critical current IC with time in polycrystalline high TC samples, traced a peak when measured versus HM, the amplitude of the sweep of the flux trapping magnetic field. We show that the sharp peak in dICO/dlnt which their model generates arises from a special feature of the formulae they use to describe IC versus HM. Pursuing an extension of these formulae, and exploiting a Brandt-Indenbom formula for the return field of the magnetized grains, we (i) reproduce observations of Altshuler et al, Batista-Leyva et al and a family of curves of dICO/dlnt reported by Cobas et al, and (ii) estimate the return fields. We also explore the peak structure of dICO/dlnt versus HM generated by using two well known empirical expressions for IC(H), and the Brandt-Indenbom formula.

  3. Edge ferromagnetism from Majorana flat bands: application to split tunneling-conductance peaks in high-Tc cuprate superconductors.

    Science.gov (United States)

    Potter, Andrew C; Lee, Patrick A

    2014-03-21

    In mean-field descriptions of nodal d-wave superconductors, generic edges exhibit dispersionless Majorana fermion bands at zero energy. These states give rise to an extensive ground-state degeneracy, and are protected by time-reversal symmetry. We argue that the infinite density of states of these flat bands make them inherently unstable to interactions, and show that repulsive interactions lead to edge ferromagnetism which splits the flat bands. This edge ferromagnetism offers an explanation for the observation of the splitting of zero-bias peaks in edge tunneling in high-Tc cuprate superconductors. We argue that this mechanism for splitting is more likely than previously proposed scenarios and describe its experimental consequences.

  4. Josephson-junction single plaquette as a model for the high-Tc grain-boundary junctions

    Science.gov (United States)

    Kim, Jinhee; Shin, Hyun Joon; Lee, Hu Jong

    1994-03-01

    We have calculated the widths of the integer and half-integer voltage steps in a square Josephson-junction single plaquette as a function of ac level for various filling factors f. The characteristic features of the step widths, corresponding to n=0, 1/2, and 1, show clear differences between small and large values of f, and are in reasonable agreement with the results observed experimentally in high-Tc single grain-boundary junctions. When the inhomogeneity in the critical current of the junctions parallel and perpendicular to the external current is introduced to the model the equations of motion for a single plaquette become equivalent to those of a dc superconducting quantum interference device in the limit of small loop inductance.

  5. Analysis of High Tc Superconducting Rectangular Microstrip Patches over Ground Planes with Rectangular Apertures in Substrates Containing Anisotropic Materials

    Directory of Open Access Journals (Sweden)

    Abderraouf Messai

    2013-01-01

    Full Text Available A rigorous full-wave analysis of high Tc superconducting rectangular microstrip patch over ground plane with rectangular aperture in the case where the patch is printed on a uniaxially anisotropic substrate material is presented. The dyadic Green’s functions of the considered structure are efficiently determined in the vector Fourier transform domain. The effect of the superconductivity of the patch is taken into account using the concept of the complex resistive boundary condition. The accuracy of the analysis is tested by comparing the computed results with measurements and previously published data for several anisotropic substrate materials. Numerical results showing variation of the resonant frequency and the quality factor of the superconducting antenna with regard to operating temperature are given. Finally, the effects of uniaxial anisotropy in the substrate on the resonant frequencies of different TM modes of the superconducting microstrip antenna with rectangular aperture in the ground plane are presented.

  6. Large low-symmetry polarons of the high-Tc, copper oxides: Formation, mobility and ordering

    Science.gov (United States)

    Bersuker, Gennadi I.; Goodenough, John B.

    1997-02-01

    A microscopic model of the evolution from antiferromagnetic insulator to superconductor on oxidation of the parent-phase (CuO 2) 2- sheets of a cuprate superconductor starts with the assumption that strong electron-lattice interactions are dominant and give a heterogeneous electronic distribution. Introduction of pseudo-Jahn-Teller vibronic coupling associated with the δ holes in the (CuO 2) (2-δ) - sheets is shown to stabilize, below a critical temperature Tp ≈ 850 K, large non-adiabatic polarons containing 5 to 7 copper centers; cooperative low-symmetry in-plane vibrations also stabilize an elastic attractive force between polarons that can overcome the longer-range Coulomb repulsion between polarons. Utilizing established parameters for isolated CuO 6 complexes gives a calculated polaron size of 5 to 7 copper centers, which compares with a measured mean size of 5.3 copper centers in underdoped samples 0 hopping. This type of motion, which is not described by conventional transport theories, gives a linear increase of the resistivity with temperature above a temperature Tϱ due to scattering of the polaron at its own border, which separates regions inside and outside the polaron of slightly different mean CuO bond length. At lower temperatures, the polaron mobility becomes activated, but at higher concentrations this change is obscured because the elastic interpolaron attractive force causes the polarons to condense into a “polaron liquid,” and below some critical temperature Td ≥ Tc the polarons undergo long-range ordering into one-dimensional polaronic stripes separated by stripes of the parent phase, which support antiferromagnetic spin fluctuations. The zig-zag polaron stripes consist of polaron pairs oriented alternately along [100] and [010] axes of a CuO 2 sheet. Formation of the ordered superstructure permits conduction of hole pairs without scattering from lattice vibrations provided there is also coupling in the third dimension between Cu

  7. Microstructure and performance of solid TC4 titanium alloy subjected to the high pulsed magnetic field treatment

    Energy Technology Data Exchange (ETDEWEB)

    Li, G.R., E-mail: liguirong@ujs.edu.cn; Li, Y.M.; Wang, F.F.; Wang, H.M.

    2015-09-25

    Highlights: • A high pulsed magnetic field was introduced to process the solid titanium alloy. • The phase transition from beta to alpha in processed alloy was discovered. • The magneto-plasticity effect was found and highlighted. • The strength and toughness of treated alloy were enhanced synchronously. - Abstract: The effect of high pulsed magnetic field with different magnetic induced intensity (B) on the microstructure and mechanical performance of solid TC4 titanium alloy was investigated. The microstructure morphology was characterized by metallographic microscope, scanning electronic microscopy and transmission electronic microscopy. The results show that the magnetic has induced the phase transformation from β to α. At 4 T the volume fraction of α phase has increased from 49% (B = 0) to 59%. Meanwhile, compared to that of original sample the dislocation density at 3 T is 4.8 times, which was the result of magneto-plasticity effect. However, the dislocation density will not always increase with B due to the dislocation pile-up effect. The mechanical properties tests show that the strength of materials is enhanced with the B increase within a certain scope. The strength and elongation of processed TC4 alloy exhibit the obvious changes: when B = 3 T the maximum strength reaches 1330 MPa which ascribes to the dislocation strengthening. It is enhanced by 7.6% compared to that of original sample. It is noted that when B = 4 T the strength and toughness are improved simultaneously which are attributed to not only the dislocation strengthening but also the amount, distribution and morphology of α phase.

  8. Vertical Cloud Climatology During TC4 Derived from High-Altitude Aircraft Merged Lidar and Radar Profiles

    Science.gov (United States)

    Hlavka, Dennis; Tian, Lin; Hart, William; Li, Lihua; McGill, Matthew; Heymsfield, Gerald

    2009-01-01

    profiles occurring 94 percent of the time during the ER-2 flights. One to three cloud layers were common, with the average calculated at 2.03 layers per profile. The upper troposphere had a cloud frequency generally over 30%, reaching 42 percent near 13 km during the study. There were regional differences. The Caribbean was much clearer than the Pacific regions. Land had a much higher frequency of high clouds than ocean areas. One region just south and west of Panama had a high probability of clouds below 15 km altitude with the frequency never dropping below 25% and reaching a maximum of 60% at 11-13 km altitude. These cloud statistics will help characterize the cloud volume for TC4 scientists as they try to understand the complexities of the tropical atmosphere.

  9. Investigation of ultra-high cycle fatigue behavior of TC17 alloy at a frequency of 20kHz%20kHz下TC17钛合金超高周疲劳性能研究

    Institute of Scientific and Technical Information of China (English)

    高潮; 程礼; 彭桦; 申景生; 邱辰霖; 刘延杰

    2012-01-01

    The bending fatigue system was developed using the piezoelectric ultrasonic fatigue testing technology and experimental investigation of the ultra-high cycles fatigue life for TC17 alloy subjected to bending fatigue deformation has been conducted.The experimental resultes show that the specimens were tested to failure in the range of 107-109 cycles and the fatigue limit decreases with the increasing number of cycles between 107 and 109 for R=-1.0 and there was no obvious fatigue limit.The S-N curve for TC17 is a continuous decline curve between 107 and 109 cycles.The fractographic study showes that fatigue failures are mostly initiated at the surface of the test specimens.When there are subsurface inclusions,fatigue cracks initiated from subsurface inclusions,and the composition of inclusions is mainly oxides of aluminums.%应用基于压电超声疲劳试验技术开发的20kHz弯曲疲劳试验系统,完成了室温下TC17合金超高周疲劳试验.结果表明:在疲劳循环大于107周次时,试样仍会发生疲劳断裂,疲劳强度随循环次数的增加而下降,并不存在明显的疲劳极限.TC17合金的应力-寿命(S-N)曲线在107~109周次的范围内为连续下降型.光学显微镜发现,TC17合金的疲劳破坏主要起源于试样表面.当存在夹杂物时,疲劳裂纹从距离表面很近的夹杂物处萌生,能谱分析表明夹杂物的成分主要是铝的氧化物.

  10. /sup 99m/Tc-aminohexylidendiphosphonate and /sup 99/mTc-Pyrophosphate in the scintigraphic diagnosis of experimental cardiomyopathy in dogs

    Energy Technology Data Exchange (ETDEWEB)

    Duska, F.; Kafka, P.; Mazurova, Y.; Hadas, L.; Vizda, J.; Palicka, V.; Grossman, V.

    1987-10-01

    Experimental cardiomyopathy was provoked in 24 dogs with high intravenous doses of adrenaline and theophylline. These lesions were studied by means of the new agent /sup 99m/Tc-AHDP and /sup 99m/Tc-PYP in comparison. Cardiomyopathy could be imaged as early as 4 h after the onset of involvement but not later than 7 days. A maximum accumulation occurred in lesions 24 h old, /sup 99m/Tc uptake in the myocardium was graded scintigraphically, /sup 99m/Tc-AHDP was accumulated in the altered myocardium to a greater extent than /sup 99m/Tc-PYP. Scintigraphic findings were in good agreement with plasma levels of creatine-kinase. A comparison with histology demonstrated that the maximum accumulation of radiopharmaceuticals occurred at the time when the development of myocardium involvement reached the stage of myocytolysis.

  11. Evidence for greater cue reactivity among low-dependent vs. high-dependent smokers.

    Science.gov (United States)

    Watson, Noreen L; Carpenter, Matthew J; Saladin, Michael E; Gray, Kevin M; Upadhyaya, Himanshu P

    2010-07-01

    Cue reactivity paradigms are well-established laboratory procedures used to examine subjective craving in response to substance-related cues. For smokers, the relationship between nicotine dependence and cue reactivity has not been clearly established. The main aim of the present study was to further examine this relationship. Participants (N=90) were between the ages 18-40 and smoked > or =10 cigarettes per day. Average nicotine dependence (Fagerström Test for Nicotine Dependence; FTND) at baseline was 4.9 (SD=2.1). Participants completed four cue reactivity sessions consisting of two in vivo cues (smoking and neutral) and two affective imagery cues (stressful and relaxed), all counterbalanced. Craving in response to cues was assessed following each cue exposure using the Questionnaire of Smoking Urges-Brief (QSU-B). Differential cue reactivity was operationally defined as the difference in QSU scores between the smoking and neutral cues, and between the stressful and relaxed cues. Nicotine dependence was significantly and negatively associated with differential cue reactivity scores in regard to hedonic craving (QSU factor 1) for both in vivo and imagery cues, such that those who had low FTND scores demonstrated greater differential cue reactivity than those with higher FTND scores (beta=-.082; p=.037; beta=-.101; p=.023, respectively). Similar trends were found for the Total QSU and for negative reinforcement craving (QSU factor 2), but did not reach statistical significance. Under partially sated conditions, less dependent smokers may be more differentially cue reactive to smoking cues as compared to heavily dependent smokers. These findings offer methodological and interpretative implications for cue reactivity studies. 2010 Elsevier Ltd. All rights reserved.

  12. Evidence for greater cue reactivity among low dependent vs. high dependent smokers

    Science.gov (United States)

    Watson, Noreen L.; Carpenter, Matthew J.; Saladin, Michael E.; Gray, Kevin M.; Upadhyaya, Himanshu P.

    2010-01-01

    Introduction Cue reactivity paradigms are well-established laboratory procedures used to examine subjective craving in response to substance-related cues. For smokers, the relationship between nicotine dependence and cue reactivity has not been clearly established. The main aim of the present study was to further examine this relationship. Methods Participants (N=90) were between the ages 18–40 and smoked ≥10 cigarettes per day. Average nicotine dependence (Fagerström Test for Nicotine Dependence; FTND) at baseline was 4.9 (SD=2.1). Participants completed four cue reactivity sessions consisting of two in vivo cues (smoking, neutral) and two affective imagery cues (stressful, relaxed), all counterbalanced. Craving in response to cues was assessed following each cue exposure using the Questionnaire of Smoking Urges—Brief (QSU-B). Differential cue reactivity was operationally defined as the difference in QSU scores between the smoking and neutral cues, and between the stressful and relaxed cues. Results Nicotine dependence was significantly and negatively associated with differential cue reactivity scores in regards to hedonic craving (QSU factor 1) for both in vivo and imagery cues, such that those who had low FTND scores demonstrated greater differential cue reactivity than those with higher FTND scores (β = −.082; p = .037; β = −.101; p = .023, respectively). Similar trends were found for the total QSU and for negative reinforcement craving (QSU factor 2), but did not reach statistical significance. Discussion Under partially sated conditions, less dependent smokers may be more differentially cue reactive to smoking cues as compared to heavily dependent smokers. These findings offer methodological and interpretative implications for cue reactivity studies. PMID:20206451

  13. Structural optimization and physical properties of TcB3 and MoB3 at high-pressure: First-principles

    Science.gov (United States)

    Ying, Chun; Bai, Xiaowan; Du, Yungang; Zhao, Erjun; Lin, Lin; Hou, Qingyu

    2016-06-01

    The thermodynamic, mechanical and dynamic properties of TcB3 and MoB3 are systematically investigated at high-pressure by first-principles within density functional theory (DFT). The calculated formation enthalpies are negative for TcB3 with considered structures under the pressure range from 0 to 100 GPa. Triboride hP4-TcB3 (i.e., TcB3 in hP4-OsB3 type structure) has the lowest formation enthalpy of -1.44 eV under ambient condition. The largest shear modulus of 240 GPa and smallest Poisson’s ratio of 0.20 for oP16-TcB3 are comparable to those of 267 GPa and 0.15 for ReB2. The calculated elastic constants show that MB3 (M=Tc and Mo) are mechanically stable at ambient conditions, except for mP8-MoB3. The estimated high hardness of 33.4 and 33.1 GPa for oP16-TcB3 and hP4-TcB3, respectively, are reported for the first time. The calculated lattice parameters for MoB3 are in good agreement with the previously theoretical and experimental studies. Below 13 GPa, hP16-MoB3 and hR24-MoB3 are thermodynamically more favorable than MoB3 in other structures. A pressure-induced phase transition is predicted at 13 GPa from hP16-MoB3 and hR24-MoB3 to hP4-MoB3. Above 13 GPa, hP4-MoB3 becomes the thermodynamically most stable phase among MoB3 in considered structures. All compounds with considered structures are metallic, and the electronic structures of MB3 are governed by a strong hybridization between M-4d and B-2p states. The strong and directional covalent bonding between M-4d and B-2p as well as the strong interlayer interactions of boron layers are correlated to the high hardness of 38.0 and 38.4 GPa for hP16-MoB3 and hR24-MoB3, respectively.

  14. From high-Tc superconductors to highly correlated Mott insulators—25 years of pulsed laser deposition of functional oxides in Leipzig

    Science.gov (United States)

    Lorenz, Michael; Hochmuth, Holger; Kneiß, Max; Bonholzer, Michael; Jenderka, Marcus; Grundmann, Marius

    2015-02-01

    Pulsed laser deposition (PLD) in Leipzig started in 1989 with Bi2Sr2Ca1Cu2O8 high-Tc superconducting thin films grown in a laser-ionization mass spectrometer. Here, we briefly review 25 years of development of advanced PLD processes in Leipzig and their application to high-Tc superconducting, wide-bandgap semiconducting and multiferroic thin films, nanostructures and composites. The first two decades were devoted to large-area and double-sided YBa2Cu3O7-δ thin films and hetero- and homoepitaxial ZnO-based films and nanowires, respectively. Based on that, transparent, oxide-based electronic devices are processed with epitaxial n-ZnO:Mg, Ga2O3, In2O3, or TiO2 films. Amorphous oxide films of p-ZnCo2O4 and p-NiO provide p-type counterparts in highly rectifying pn-junction devices and are an environmentally friendly alternative. Magnetoelectric multiferroic composites, and highly correlated iridate thin films are other current hot research topics. PLD appears as one of the most flexible growth techniques for functional oxides on research and demonstrator level.

  15. Bearing design for flywheel energy storage using high-TC superconductors

    Science.gov (United States)

    Hull, John R.; Mulcahy, Thomas M.

    2000-01-01

    A high temperature superconductor material bearing system (38) This system (38) includes a rotor (50) having a ring permanent magnet (60), a plurality of permanent magnets (16, 20 and 70) for interacting to generate levitation forces for the system (38). This group of magnets are a push/pull bearing (75). A high temperature superconductor structure (30) interacts with the ting permanent magnet (60) to provide stabilizing forces for the system (38).

  16. Tl sub 0. 75 Pb sub 0. 20 Sb sub 0. 05 Ca sub 2 Ba sub 3 Cu sub 4 O sub y high Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kostadinov, I.Z.; Mateev, M.D.; Tihov, J.; Skumriev, V.; Tsakin, E. (Faculty of Physics, Sofia Univ. (Bulgaria)); Petrov, O.; Dinolova, E. (Inst. of Applied Mineralogy, Academy of Sciences, Sofia (Bulgaria)); Kovachev, V. (Inst. of Solid State Physics, Acadademy of Sciences, Sofia (Bulgaria))

    1989-12-01

    A new Tl based high Tc superconducting phase was studied. The pellets were prepared from nitrates and were found to be single phased. The critical temperature was determined to be 121K. The X-ray powder diffraction demonstrated tetragonal structure with c = 31.9A. The SEM analysis also indicates monophase composition. (orig.).

  17. A cervid vocal fold model suggests greater glottal efficiency in calling at high frequencies.

    Directory of Open Access Journals (Sweden)

    Ingo R Titze

    Full Text Available Male Rocky Mountain elk (Cervus elaphus nelsoni produce loud and high fundamental frequency bugles during the mating season, in contrast to the male European Red Deer (Cervus elaphus scoticus who produces loud and low fundamental frequency roaring calls. A critical step in understanding vocal communication is to relate sound complexity to anatomy and physiology in a causal manner. Experimentation at the sound source, often difficult in vivo in mammals, is simulated here by a finite element model of the larynx and a wave propagation model of the vocal tract, both based on the morphology and biomechanics of the elk. The model can produce a wide range of fundamental frequencies. Low fundamental frequencies require low vocal fold strain, but large lung pressure and large glottal flow if sound intensity level is to exceed 70 dB at 10 m distance. A high-frequency bugle requires both large muscular effort (to strain the vocal ligament and high lung pressure (to overcome phonation threshold pressure, but at least 10 dB more intensity level can be achieved. Glottal efficiency, the ration of radiated sound power to aerodynamic power at the glottis, is higher in elk, suggesting an advantage of high-pitched signaling. This advantage is based on two aspects; first, the lower airflow required for aerodynamic power and, second, an acoustic radiation advantage at higher frequencies. Both signal types are used by the respective males during the mating season and probably serve as honest signals. The two signal types relate differently to physical qualities of the sender. The low-frequency sound (Red Deer call relates to overall body size via a strong relationship between acoustic parameters and the size of vocal organs and body size. The high-frequency bugle may signal muscular strength and endurance, via a 'vocalizing at the edge' mechanism, for which efficiency is critical.

  18. Oxygen stabilization induced enhancement in superconducting characteristics of high-Tc oxides

    Science.gov (United States)

    Wu, M. K.; Chen, J. T.; Huang, C. Y.

    1991-01-01

    In an attempt to enhance the electrical and mechanical properties of the high temperature superconducting oxides, high T(sub c) composites were prepared composed of the 123 compounds and AgO. The presence of extra oxygen due to the decomposition of AgO at high temperature is found to stabilize the superconducting 123 phase. Ag is found to serve as clean flux for grain growth and precipitates as pinning center. Consequently, almost two orders of magnitude enhancement in critical current densities were also observed in these composites. In addition, these composites also show much improvement in workability and shape formation. On the other hand, proper oxygen treatment of Y5Ba6Cu11Oy was found to possibly stabilize superconducting phase with T(sub c) near 250 K. I-V, ac susceptibility, and electrical resistivity measurements indicate the existence of this ultra high T(sub c) phase in this compound. Detailed structure, microstructure, electrical, magnetic and thermal studies of the superconducting composites and the ultra high T(sub c) compound are presented and discussed.

  19. Electronic structure Fermi liquid theory of high Tc superconductors: Comparison of predictions with experiments

    Science.gov (United States)

    Yu, Jaejun; Freeman, A. J.

    1991-01-01

    Predictions of local density functional (LDF) calculations of the electronic structure and transport properties of high T(sub c) superconductors are presented. As evidenced by the excellent agreement with both photoemission and positron annihilation experiments, a Fermi liquid nature of the 'normal' state of the high T(sub c) superconductors become clear for the metallic phase of these oxides. In addition, LDF predictions on the normal state transport properties are qualitatively in agreement with experiments on single crystals. It is emphasized that the signs of the Hall coefficients for the high T(sub c) superconductors are not consistent with the types of dopants (e.g., electron-doped or hole-doped) but are determined by the topology of the Fermi surfaces obtained from the LDF calculations.

  20. Microbial impacts on (99m)Tc migration through sandstone under highly alkaline conditions relevant to radioactive waste disposal.

    Science.gov (United States)

    Smith, Sarah L; Boothman, Christopher; Williams, Heather A; Ellis, Beverly L; Wragg, Joanna; West, Julia M; Lloyd, Jonathan R

    2017-01-01

    Geological disposal of intermediate level radioactive waste in the UK is planned to involve the use of cementitious materials, facilitating the formation of an alkali-disturbed zone within the host rock. The biogeochemical processes that will occur in this environment, and the extent to which they will impact on radionuclide migration, are currently poorly understood. This study investigates the impact of biogeochemical processes on the mobility of the radionuclide technetium, in column experiments designed to be representative of aspects of the alkali-disturbed zone. Results indicate that microbial processes were capable of inhibiting (99m)Tc migration through columns, and X-ray radiography demonstrated that extensive physical changes had occurred to the material within columns where microbiological activity had been stimulated. The utilisation of organic acids under highly alkaline conditions, generating H2 and CO2, may represent a mechanism by which microbial processes may alter the hydraulic conductivity of a geological environment. Column sediments were dominated by obligately alkaliphilic H2-oxidising bacteria, suggesting that the enrichment of these bacteria may have occurred as a result of H2 generation during organic acid metabolism. The results from these experiments show that microorganisms are able to carry out a number of processes under highly alkaline conditions that could potentially impact on the properties of the host rock surrounding a geological disposal facility for intermediate level radioactive waste. Copyright © 2016. Published by Elsevier B.V.

  1. Measurement of repulsive force of high Tc materials due to Meissner effect and its two dimensional distribution

    Science.gov (United States)

    Ishigaki, H.; Itoh, M.; Hida, A.; Endo, H.; Oya, T.

    1991-03-01

    As a basic study for magnetic bearings using high-Tc superconductors, evaluations of the materials were conducted. These evaluations included measurements of the repulsive force and lateral restoring force of various kinds of YBCO pellets. Pure air, which was supplied in the process of fabrication, and the presence of Ag in YBCO showed evidence of the effects of increasing the repulsive force. The lateral restoring force which was observed in the lateral displacement of a levitated permanent magnet over YBCO pellets was also affected by pure air and the presence of Ag. A new measuring instrument for magnetic fields was developed by using a highly sensitive force sensor. Because this instrument has the capability of measuring the repulsive force due to the Meissner effect, it was used for evaluating the two-dimensional distribution of superconducting properties. Results show that the pellets had nonuniform superconducting properties. The two-dimensional distribution of residual flux density on the pellets which had been cooled in a magnetic field (field cooling) was also observed by means of the instrument. The mechanism for generating lateral force is discussed in relation to the distribution.

  2. Bombesin receptors and transplanted stem cells in rat brain: High-resolution scan with 99mTc BN1.1

    Science.gov (United States)

    Scopinaro, F.; Paschali, E.; Di Santo, G.; Antonellis, T.; Massari, R.; Trotta, C.; Gourni, H.; Bouziotis, P.; David, V.; Soluri, A.; Varvarigou, A. D.

    2006-12-01

    The aim of this work is to detect the presence of transplanted stem cells (TSC) in rat brain with high-resolution (HR) scintigraphy and labelled bombesin (BN). BN is a morphogen for Central Nervous System (CNS) as well as for other organs: CNS-oriented TSC over-express BN Receptors (BNR). BN is also a neurotransmitter and modulates several functions of CNS. 99mTc labelled BN-like peptide scan of CNS is the ideal method to detect growing TSC once knowing normal distribution of BNRs in CNS. HR Planar and single photon emission computerized tomography (SPECT) images of rat brain were performed with new HR detectors (Li-tech, Italy). Pertechnetate, 99mTc HMPAO and the new 99mTc BN1.1 (patented) were i.v. administered in five rats. HR SPECT of 99mTc BN1.1 detected olfactory tract, fronto-lateral cortex, cerebellum, basal ganglia and amygdale. Results of SPECT were confirmed by bio-distribution study performed after autopsy of three of the five rats. The remaining two rats underwent cerebral lesions followed by transplant of TSC. Three months later, HR scintigraphy was repeated and showed images completely different from previous basal study, with hot spot of 99mTc BN1.1 corresponding to the site of TSC transplant. Immuno-histochemistry confirmed the presence of viable TSC. Not only 99mTc BN1.1 HR scan showed viability of transplanted TSC but also the "background brain" was the still now unknown map of BNR in mammalian brain.

  3. Magnetic-flux dynamics of high-Tc superconductors in weak magnetic fields

    DEFF Research Database (Denmark)

    Il’ichev, E. V.; Jacobsen, Claus Schelde

    1994-01-01

    Aspects of magnetic-flux dynamics in different types of samples of the high-temperature superconductor YBa2Cu3Ox have been investigated in magnetic fields below 1 Oe and at 77 K. The experiments were carried out in an arrangement including a field coil, a flat sample perpendicular to the field...

  4. High-frequency waves following PKP-CDIFF at distances greater than 155°

    Science.gov (United States)

    Nakanishi, Ichiro

    1990-04-01

    Using a seismic network in Hokkaido-Tohoku region, Japan we observe PKP waves in the distance range 152 to 157°from a deep earthquake in Argentina. The seismic network consists of 26 stations and provides us with a data set of dense distance sampling. The examination of amplitude variation of PKP-BC and PKP-Cdiff with distance locates the C-cusp at about 155.5° for a surface source for the path from Argentina to Japan. This C-cusp position suggests a P velocity of 10.27 km/s at the bottom of the outer core. The bandpass filtering of the data shows that high-frequency waves are observed following PKP-Cdiff at distances beyond the C-cusp. The waves are characterized by a dominant frequency of about 2 to 3 Hz, a long duration of oscillation until the arrival of PKP-AB, and an apparent onset slowness of about 4 s/deg, which is approximately equal to that of PKP-AB in the distance range. The onset time of the high-frequency waves seems to be consistent with the least time of the scattering of PKP-BC on the receiver side near the bottom of the upper mantle.

  5. Greater virulence of highly pathogenic H5N1 influenza virus in cats than in dogs.

    Science.gov (United States)

    Kim, Heui Man; Park, Eun Hye; Yum, Jung; Kim, Hyun Soo; Seo, Sang Heui

    2015-01-01

    Highly pathogenic H5N1 influenza virus continues to infect animals and humans. We compared the infectivity and pathogenesis of H5N1 virus in domestic cats and dogs to find out which animal is more susceptible to H5N1 influenza virus. When cats and dogs were infected with the H5N1 virus, cats suffered from severe outcomes including death, whereas dogs did not show any mortality. Viruses were shed in the nose and rectum of cats and in the nose of dogs. Viruses were detected in brain, lung, kidney, intestine, liver, and serum in the infected cats, but only in the lung in the infected dogs. Genes encoding inflammatory cytokines and chemokines, Toll-like receptors, and apoptotic factors were more highly expressed in the lungs of cats than in those of dogs. Our results suggest that the intensive monitoring of dogs is necessary to prevent human infection by H5N1 influenza virus, since infected dogs may not show clear clinical signs, in contrast to infected cats.

  6. Fabrication of high-Tc superconducting hot electron bolometers for terahertz mixer applications

    Science.gov (United States)

    Villegier, Jean-Claude; Degardin, Annick F.; Guillet, Bruno; Houze, Frederic; Kreisler, Alain J.; Chaubet, Michel

    2005-03-01

    Superconducting Hot Electron Bolometer (HEB) mixers are a competitive alternative to Schottky diode mixers or other conventional superconducting receiver technologies in the terahertz frequency range because of their ultrawide bandwidth (from millimeter waves to the visible), high conversion gain, and low intrinsic noise level, even at 77 K. A new technological process has been developed to realize HEB mixers based on high temperature superconducting materials, using 15 to 40 nm thick layers of YBa2Cu3O7-δ (YBCO), sputtered on MgO (100) substrates by hollow cathode magnetron sputtering. Critical temperature values of YBCO films were found in the 85 to 91 K range. Sub-micron HEB bridges (0.8 μm x 0.8 μm) were obtained by combining electronic and UV lithography followed by selective etching techniques. Realization of YBCO HEB coupling to planar integrated gold antennas was also considered.

  7. Anisotropy Effect on Levitation Performance of Bulk High-Tc Superconductors Above a Permanent Magnet Guideway

    Science.gov (United States)

    Zheng, Jun; Liao, Xinglin; Jing, Hailian; Lin, Qunxu; Ma, Guangtong; Yen, Fei; Wang, Suyu; Wang, Jiasu

    The anisotropy properties of bulk high-temperature superconductors (HTSCs) are taken into consideration for the application of high-temperature superconducting (HTS) Maglev systems, which are especially based on the different flux-trapping capabilities as well as critical current density, Jc, values between the growth section boundary (GSB) and the growth sections (GS) in bulk superconductors. By adjusting the angle between the GSB of bulk HTSCs and the strongest magnetic field position of a permanent magnet guideway (PMG), the levitation force and its relaxation processes are compared at different field-cooling conditions. Experimental results show that the levitation capability and the suppression of levitation force decay can be enhanced by optimizing the GS/GSB alignment of every bulk HTSC above the PMG. Meanwhile, our conclusions may provide references to other HTS maglev systems with small levitation gaps, i.e., superconducting magnetic bearings.

  8. Progress in high Tc magnetic sensors and their applications. [Y-Ba-Cu-O

    Energy Technology Data Exchange (ETDEWEB)

    Donaldson, G.B.; Bowman, R.M.; Cochran, A.; Kirk, K.J.; Pegrum, C.M. (Dept. of Physics and Applied Physics, Strathclyde Univ., Glasgow (United Kingdom)); Macfarlane, J.C. (Div. of Applied Physics, CSIRO, Lindfield (Australia))

    1992-01-01

    We report recent progress on the development of components needed for high T[sub c] SQUID magnetic sensors, and on some of the early applications which are appearing or can be foreseen. The SNS type edge junction, and the step edge and biepitaxial grain boundary junction technologies are considered and we include details of our own YBCO device based on steps which are Ar ion-milled in MgO substrates. A review of applications prospects for these detectors will be given in the light of the available noise performance which for high T[sub c] DC SQUIDs, at much less than 10[sup -4] [Phi][sub 0] Hz[sup -1/2], is now better than for commercial low T[sub c] RF SQUIDs. Illustrations are given from clinical biomagnetism and from non-destructive evaluation of conducting materials.

  9. On field effect studies and superconductor-insulator transition in high-Tc cuprates

    Science.gov (United States)

    Dubuis, G.; Bollinger, A. T.; Pavuna, D.; Božović, I.

    2013-07-01

    We summarize previous field effect studies in high- T c cuprates and then discuss our method to smoothly tune the carrier concentration of a cuprate film over a wide range using an applied electric field. We synthesized epitaxial one-unit-cell thick films of La2- x Sr x CuO4 and from them fabricated electric double layer transistor devices utilizing various gate electrolytes. We were able to vary the carrier density by about 0.08 carriers per Cu atom, with the resulting change in T c of 30 K. The superconductor-insulator transition occurred at the critical resistance very close to the quantum resistance for pairs, R Q = h/(2 e)2 = 6.5 kΩ. This is suggestive of a quantum phase transition, possibly driven by quantum phase fluctuations, between a "Bose insulator" and a high- T c superconductor state.

  10. Design aspects and comparison between high Tc superconducting coplanar waveguide and microstrip line

    Science.gov (United States)

    Kong, K. S.; Bhasin, K. B.; Itoh, T.

    1991-01-01

    The high T sub c superconducting microstrip line and coplanar waveguide are compared in terms of the loss characteristics and the design aspects. The quality factor Q values for each structure are compared in respect to the same characteristic impedance with the comparable dimensions of the center conductor of the coplanar waveguide and the strip of the microstrip line. Also, the advantages and disadvantages for each structure are discussed in respect to passive microwave circuit applications.

  11. Microscopic Superconductivity and Room Temperature Electronics of High-Tc Cuprates

    Institute of Scientific and Technical Information of China (English)

    LIU Fu-Sui; CHEN Wan-Fang

    2008-01-01

    This paper points out that the Landau criterion for macroscopic superfluidity of He H is only a criterion for microscopic superfluidity of 4He, extends the Landau criterion to microscopic superconductivity in fermions (electron and hole) system and system with Cooper pairs without long-range phase coherence. This paper gives another three non-superconductive systems that are of microscopic superconductivity. This paper demonstrates that one application of microscopic superconductivity is to establish room temperature electronics of the high-To cuprates.

  12. A very High Performance Multi Purpose Computing Card for TM/TC and Control Systems

    OpenAIRE

    Wittkamp, Markus; Zigiotto, Anderson

    2009-01-01

    For future sounding rocket and balloon missions, a powerful processing system is needed for ambitious rate and attitude control algorithms as well as data acquisition for telemetry with high data rates (e.g. digital video). The card comprises a dual core DSP together with a large FPGA to collect and process experiment data, build telemetry data streams and decode commands for the onboard experiment module network. Due to the use of FPGA controlled periphery the Euro sized card offers th...

  13. Correlation of normal and superconducting properties and unified approach to the description of high Tc oxides

    Science.gov (United States)

    Kresin, V. Z.; Wolf, S. A.

    1991-01-01

    We present a unified approach based on the Fermi liquid picture which allows us to describe the normal as well as the superconducting properties of the doped cuprates. The theory that is presented is for the doped compounds which are metallic. One can distinguish two interrelated, but nevertheless, different directions in the physics of high T(sub c): one involving the problem of carrier doping and the transition to the metallic state, and the second being the description of the metallic state. It is important that this metallic phase undergoes the transition into the superconducting state; as a result, our analysis is directly related to the origin of high T(sub c). We are using a quasi-2D Fermi liquid model to estimate the fundamental parameters of these very interesting materials. We find that this description is able to describe these materials and also that phonons and plasmons play a major role in the mechanism of high T(sub c).

  14. Superconductivity in the high-Tc Bi-Ca-Sr-Cu-O system - Phase identification

    Science.gov (United States)

    Hazen, R. M.; Prewitt, C. T.; Angel, R. J.; Ross, N. L.; Finger, L. W.

    1988-01-01

    Four phases are observed in superconducting Bi-Ca-Sr-Cu-O samples. The superconducting phase, with onset temperature near 120 K, is a 15.4-A-layered compound with composition near Bi2Ca1Sr2Cu2O9 and an A-centered orthorhombic unit subcell 5.41 x 5.44 x 30.78 A. X-ray diffraction and electron microscopy data are consistent with a structure of alternating perovskite and Bi2O2 layers. High-resolution transmission electron microscopy images reveal a b-axis superstructure of 27.2 A, numerous (001) stacking faults, and other defects.

  15. The discovery of high-Tc superconductivity-unexpected discovery, unconventional behaviour

    Directory of Open Access Journals (Sweden)

    A. Andreone

    2006-09-01

    Full Text Available   A brief review on some peculiar properties of high temperature superconductors (HTS is presented. Twenty years after the discovery, it appears more and more clear that the behaviour of this new class of materials is remarkably different from what have been re-classified as “conventional” superconductors. In the following we will focus our attention on the study of two phenomena, namely the Josephson effect and the Meissner effect, where the unconventional nature of superconductivity in HTS offers exciting perspectives both for the understanding of the underlying mechanism, so far still unknown, and for the large potential of applications in different areas of superconducting electronics.

  16. Nodal quasi-particles of the high-Tc superconductors as carriers of heat

    Directory of Open Access Journals (Sweden)

    K. Behnia

    2006-09-01

    Full Text Available   In the quest for understanding correlated electrons, high-temperature superconductivity remains a formidable challenge and a source of insight. This paper briefly recalls the central achievement by the study of heat transport at low temperatures. At very low temperatures, nodal quasi-particles of the d-wave superconducting gap become the main carriers of heat. Their thermal conductivity is unaffected by disorder and reflects the fine structure of the superconducting gap. This finding had led to new openings in the exploration of other unconventional superconductors

  17. Interaction of microwave radiation with high-Tc films of different microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Konopka, J.; Jung, G.; Gierlowski, P.; Kula, W.; Konopka, A.; Lewandowski, S.J. (Inst. of Physics, Polish Academy of Sciences, Warszawa (Poland)); Sobolewski, R. (Inst. of Physics, Polish Academy of Sciences, Warszawa (Poland) Dept. of Electrical Engineering, Univ. of Rochester, NY (USA))

    1989-12-01

    We performed microwave detection and emission experiments on Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O thin films fabricated on several crystalline substrates using a chemical-spray technique and a dc-magnetron-sputtering process. Our experiments revealed a strong correlation between the film microstructure and its microwave properties. Most pronounced nonlinear effects were observed in highly granular Y-Ba-Cu-O films deposited on ZrO{sub 2}. Improvement in the film microstructure led to a substantial decrease of the microwave noise emission. (orig.).

  18. Future prospects of high Tc superconductors-coated conductors and their applications

    Science.gov (United States)

    Shiohara, Yuh; Yoshizumi, Masateru; Takagi, Yuji; Izumi, Teruo

    2013-01-01

    The research and development of high-temperature superconducting wires, especially yttrium-based coated conductors (CCs), and their energy applications have been expected to reduce CO2 emissions. This article reviews recent progress in this area, mainly focusing on the results obtained by national projects in Japan. The Ic (critical current) × L (wire length) value of CCs has been improved to reach 466,752 A m (572 A/cm-W, 816 m), which exceeds that of Bi-system wires. CCs have also been improved in terms of in-field performance and AC loss reduction to meet market requirements. Power applications such as superconducting magnetic energy storage (SMES) systems, power cables and transformers have been developed using CCs in the current project. Because of fundamental research on high-capacity power cables, a low AC loss of 0.8 W/m-ph at 3 kA and 73.7 K was achieved. System design and fundamental research were performed on a 2GJ-class SMES system and a 20 MVA-class transformer. Based on the technologies developed by the end of the current project (FY2012), the innovation process of those applications will reach the implementation stage, where the long-term reliability tests will be performed. The process is expected to reach the penetration and propagation stage around 2020.

  19. Low-frequency noise in high-{Tc} superconductor Josephson junctions, SQUIDs, and magnetometers

    Energy Technology Data Exchange (ETDEWEB)

    Miklich, A.H.

    1994-05-01

    Design and performance of high-T{sub c} dc superconducting quantum interference devices (SQUEDs), junctions that comprise them, and magnetometers made from them are described, with attention to sources of 1/f noise. Biepitaxial junctions are found to have large levels of critical current fluctuations which make them unsuitable for low-noise SQUIDS; this suggests a poorly connected interface at the grain boundary junction. SQUIDs from bicrystal junctions have levels of critical current noise controllable using bias current reversal techniques which leave the noise white down to frequencies of a few Hz. A SQUID with an energy resolution of 1.5{times}10{sup {minus}30} J Hz{sup {minus}1} at 1 Hz is reported. Magnetometers in which a (9 mm){sup 2} pickup loop is directly coupled to a SQUID body have achieved field resolutions of 93 fT Hz{sup {minus}1/2} down to frequencies below I Hz, improving to 39 fT Hz{sup {minus}1/2} at 1 Hz with the addition of a 50mm-diameter single-turn flux transformer. Poor coupling to pickup loop makes it difficult to satisfy competing goals of high field resolution and small detector size necessary for multichannel biomagnetic imaging. Improved coupling is demonstrated by the use of multiturn-input-coil flux transformers, and a resolution of 35 fT Hz{sup {minus}1/2} in the white noise region is reported with a (10 mm){sup 2} pickup loop. However, additional 1/f noise from processed multilayer structures in the transformer limits the resolution at 1 Hz to 114 fT Hz{sup {minus}1/2}. High-T{sub c} SQUIDs exhibit additional 1/f noise when cooled in a nonzero static magnetic field because of additional flux vortices trapped in the film, with the noise power at 1 Hz typically increasing by a factor of 10--20 in a field of 0.05mT (0.5 G). Finally, a SQUID-based voltmeter with a resolution of 9.2 pV.Hz{sup {minus}1/2} at 10 Hz (24 pV Hz{sup {minus}1/2} at 1 Hz) is described.

  20. Surface Optimization of RBa2Cu3O7-δ (R=Y, Nd) Epitaxial High Tc Films for In Situ Photoemission Studies

    Science.gov (United States)

    Abrecht, M.; Schmauder, T.; Ariosa, D.; Touzelet, O.; Rast, S.; Onellion, M.; Pavuna, D.

    One of the intrinsic difficulties for in situ photoemission studies of high Tc oxide films is the surface volatility, especially the oxygen loss. In order to solve this problem, we have constructed a dedicated system for high Tc film surface studies, in particular for ARPES measurements. Here we briefly describe our pulsed laser deposition (PLD) system that is linked to the photoemission chamber at the Synchrotron Radiation Center (SRC) in Wisconsin, and discuss crystallographic and electronic properties measured on epitaxial YBa2Cu3O7-δ (YBCO) and NdBa2Cu3O7-δ (NBCO) films. Resistivity and XRD studies show that the best c axis epitaxial films, with Tc (onset)=92 K (Tc0=90.5 K), are monophase and single crystalline with crystal coherence up to almost 1 µm. Initial core level photoemission study indicates that, for YBCO on SrTiO3 (without any buffer layer), the Ba oxide layer tends to be the dominant surface layer. Further experiments are underway to reproducibly detect sharp Fermi edge and perform ARPES study on optimally doped film surfaces.

  1. Experimental and theoretical investigation on high-Tc superconducting intrinsic Josephson junctions

    Science.gov (United States)

    Grib, Alexander; Shukrinov, Yury; Schmidl, Frank; Seidel, Paul

    2010-11-01

    Within the last years many groups have realized and investigated different types of intrinsic Josephson junction (IJJ) arrays out of high-temperature superconducting single crystals or thin films. We tried to improve the synchronization between the junctions by external shunts. Mesa structures as well as microbridges on vicinal cut substrates showed multi-branch behaviour in their IV characteristics and random switching between branches. Theoretical modelling was done investigating phase dynamics and stability numerically as well as analytically. Branch structure in current voltage characteristics of IJJ is studied in the framework of different models, particularly, in capacitevely coupled Josephson junctions (CCJJ) model and CCJJ model with diffusion current. Results of modelling of return current in IV characteristics for stacks with different number of IJJ are presented. We discussed the possible mechanisms of synchronization and the ranges of stability. Conclusions with respect to application of such arrays such as radiation sources were given.

  2. Magneto-optical studies of magnetization processes in high-Tc superconductors structure.

    Energy Technology Data Exchange (ETDEWEB)

    Vlasko-Vlasox, V. K.

    1998-12-02

    Magneto-optical imaging is a powerful tool for nondestructive quality control and scientific research through visualization of magnetic fields around any magnetic flux or current carrying sample. It allows real time observations of domain structures and their transformations in magnetics, static and dynamic field patterns due to inhomogeneous currents in electric circuits and superconductors, and reveals distortions of the fields due to defects. In addition to qualitative pictures showing different details in the intensities of the magneto-optical images, one can obtain quantitative maps of field distributions and retrieve values of the underlying currents or magnetization variations. In this review we discuss the advantages of magneto-optics for studies of superconductors, show its place among other techniques, and report recent results in magneto-optical investigations of high temperature superconductors (HTS).

  3. Compensated electron and hole pickets in an underdoped high Tc superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Neil [Los Alamos National Laboratory; Altarawneh, Moaz M [Los Alamos National Laboratory; Mielke, Charles H [Los Alamos National Laboratory; Sebastian, Suchitra E [CAMBRIDGE U; Goddard, P A [U OF OXFORD; Liang, Ruixing [U BRITISH COLUMBIA; Bonn, D A [U BRITISH COLUMBIA; Hardy, W N [U BRITISH COLUMBIA; Andersen, O K [MAX PLANCK INST.; Lonzarich, G G [CAMBRIDGE U

    2010-01-01

    Important to the question of high temperature superconductivity is whether bound fermionic pairs with zero or finite momentum - exhibiting bosonic physics - are involved. Here we use angle-dependent magnetic quantum oscillation measurements in underdoped YBa{sub 2}Cu{sub 3}O{sub 6+x} to reveal two significantly differently corrugated small sections of Fermi surface, identifying them as comprising opposite carriers located at different locations of the Brillouin zone. The surprising finding that these disproportionately heavy small pockets are equal in size indicates they are prone to a finite momentum excitonic insulator instability. We discuss the possibility that reducing the doping drives YBa{sub 2}Cu{sub 3}O{sub 6+x} closer to an instability of this nature, its ultimate realization occuring at the metal-insulator quantum critical point, accompanied by a potential enhancement of superconducting transition temperatures.

  4. High-Tc Superconductor Detection Coils for a Magnetic Resonance System

    Institute of Scientific and Technical Information of China (English)

    康琳; 吴培亨; 潘俊; 蔡卫星; 杨森祖; 曹春海

    2002-01-01

    Considering that in a magnetic resonance system, if the detection coil contributes dominantly to the system noise, the performance of the whole system can certainly be improved by switching to a detection coil made of a high-temperature superconductor, and using YBa2Cu3O7 thinfilms on 25 × 25 mm2 LaAIO3 substrates, we have prepared two kinds of detection coils: single-coil and two-coil. Encouragingly, their quality factors are measured to be Q > 2500 for two-coil (at 22.566MHz and 77K) and Q > 5500 for single-coil (at 92.3MHz and 77K),respectively. Here, we describe the details of the design, fabrication and testing of the coils.

  5. Short-circuit experiments on a high Tc-superconducting cable conductor

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Jensen, E.H.; Traholt, C.

    2002-01-01

    A high temperature superconductor (HTS) cable conductor (CC) with a critical current of 2.1 kA was tested over a range of short-circuit currents up to 20 kA. The duration of the short-circuit currents is 1 s. Between each short-circuit test the critical current of the HTS CC was measured in order...... to detect degradation due to the short-circuit current. During the over-current testing the current and voltage along the CC were measured as well as its temperature. Significant warming above the critical temperature occurs for short-circuit currents of 10 kA and above. No critical current degradation...

  6. Compensated electron and hole pickets in an underdoped high Tc superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Neil [Los Alamos National Laboratory; Altarawneh, Moaz M [Los Alamos National Laboratory; Mielke, Charles H [Los Alamos National Laboratory; Sebastian, Suchitra E [CAMBRIDGE U; Goddard, P A [U OF OXFORD; Liang, Ruixing [U BRITISH COLUMBIA; Bonn, D A [U BRITISH COLUMBIA; Hardy, W N [U BRITISH COLUMBIA; Andersen, O K [MAX PLANCK INST.; Lonzarich, G G [CAMBRIDGE U

    2010-01-01

    Important to the question of high temperature superconductivity is whether bound fermionic pairs with zero or finite momentum - exhibiting bosonic physics - are involved. Here we use angle-dependent magnetic quantum oscillation measurements in underdoped YBa{sub 2}Cu{sub 3}O{sub 6+x} to reveal two significantly differently corrugated small sections of Fermi surface, identifying them as comprising opposite carriers located at different locations of the Brillouin zone. The surprising finding that these disproportionately heavy small pockets are equal in size indicates they are prone to a finite momentum excitonic insulator instability. We discuss the possibility that reducing the doping drives YBa{sub 2}Cu{sub 3}O{sub 6+x} closer to an instability of this nature, its ultimate realization occuring at the metal-insulator quantum critical point, accompanied by a potential enhancement of superconducting transition temperatures.

  7. Fabrication and testing of long length high-{Tc} composite conductors. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, L.M.

    1997-12-31

    Presently some methods of HTS-conductors processing are under study in the authors laboratory. ``Powder-in-tube`` (PIT), ``Jelly-roll``, electrophorethis are among them. PIT process has developed predominantly both in a view of the achieved J{sub c} values Bi-2223 phase was used as a core material for these tapes. Since the main purpose of the task order was to enhance the development of long length high temperature superconductor tapes, the authors have considered reasonable to lay the perfection idea of the PIT process step by step or tape by tape. To realize it they have assumed, keeping stable the basic scheme of PIT process, to vary some technological parameters which are as follows: (1) type of initial powder; (2) sheath material; (3) tape construction (filaments number, cross section e.a.); and (4) processing regimes. This report covers the fabrication process and characteristics of the produced conductors.

  8. The string universe high T$_{c}$ superconductor or quantum Hall conductor?

    CERN Document Server

    Ellis, Jonathan Richard; Nanopoulos, Dimitri V

    1992-01-01

    Our answer is the latter. Space-time singularities, including the initial one, are described by world-sheet topological Abelian gauge theories with a Chern-Simons term. Their effective $N=2$ supersymmetry provides an initial fixed point where the Bogomolny bound is saturated on the world-sheet, corresponding to an extreme Reissner-Nordstrom solution in space-time. Away from the singularity the gauge theory has world-sheet matter fields, bosons and fermions, associated with the generation of target space-time. Because the fermions are complex (cf the Quantum Hall Effect) rather than real (cf high-$T_c$ superconductors) the energetically-preferred vacuum is not parity or time-reversal invariant, and the associated renormalization group flow explains the cosmological arrow of time, as well as the decay of real or virtual black holes, with a monotonic increase in entropy.

  9. Flip-chip-type high-Tc gradiometer for biomagnetic measurements in unshielded environment

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A flip-chip-type gradiometer has been constructed with a 10 mm×5 mm planar DC-SQUID gradiometer fabricated on a SrTiO3 bicrystal substrate and a flux transformer made from a YBCO*/YBCO/CeO2/YSZ multilayer on a φ50.8 mm Si wafer. The coupling coefficient between the flux transformer and the planar gradiometer is 0.18. The transformer increases effectively the resolution of the gradiometer. A magnetic field gradient resolution of 73 fT·cm-1·Hz-1/2 in the white region and 596 fT·cm-1Hz-1/2 at 1 Hz has been obtained. High quality magnetocardiogram signals have been successfully measured by using this flip-chip-type gradiometer in an unshielded environment.

  10. Flip-chip-type high- T_c gradiometer for biomagnetic measurements in unshielded environment

    Institute of Scientific and Technical Information of China (English)

    田永君; 王天生; 陈珂; 漆汉宏; 陈烈; 郑东宁; Sven; LINZEN; Frank; SCHMIDL; Paul; SEIDEL

    2000-01-01

    A flip-chip-type gradiometer has been constructed with a 10 mm × 5 mm planar DC-SQUID gradiometer fabricated on a SrTiO3 bicrystal substrate and a flux transformer made from a YB-CO* /YBCO/CeO2/YSZ multilayer on a φ50.8 mm Si wafer. The coupling coefficient between the flux transformer and the planar gradiometer is 0.18. The transformer increases effectively the resolution of the gradiometer. A magnetic field gradient resolution of 73 fT·cm-1·Hz-1/2 in the white region and 596 fT·cm-1Hz-1/2 at 1 Hz has been obtained. High quality magnetocardiogram signals have been successfully measured by using this flip-chip-type gradiometer in an unshielded environment.

  11. Monitoring of Spectral Map Changes from Normal State to Superconducting State in High-TC Superconductor Films Using Raman Imaging

    Directory of Open Access Journals (Sweden)

    J. L. González-Solís

    2015-01-01

    Full Text Available We have explored the chemical structure of TlBa2Ca2Cu3O9 high-TC superconductor films with Tl-1223 phase to monitor spectral map changes from normal state to superconducting state using the technique of Raman imaging. Raman images were performed for 12 different temperatures in the 77–293 K range. At room temperature, the Raman images were characterized by a single color but as the temperature dropped a new color appeared and when the temperature of 77 K is reached and the superconducting state is assured, the Raman images were characterized by the red, green, and blue colors. Our study could suggest that the superconducting state emerged around 133 K, in full agreement with those reported in the literature. A cross-checking was done applying principal component analysis (PCA to other sets of Raman spectra of our films measured at different temperatures. PCA result showed that the spectra can be grouped into two temperature ranges, one in the 293–153 K range and the other in the 133–77 K range suggesting that transition to the superconducting state occurred at some temperature around 133 K. This is the first report of preliminary results evaluating the usefulness of Raman imaging in determination of transition temperature of superconductor films.

  12. Field-dependent critical state of high-Tc superconducting strip simultaneously exposed to transport current and perpendicular magnetic field

    Science.gov (United States)

    Xue, Cun; He, An; Yong, Huadong; Zhou, Youhe

    2013-12-01

    We present an exact analytical approach for arbitrary field-dependent critical state of high-Tc superconducting strip with transport current. The sheet current and flux-density profiles are derived by solving the integral equations, which agree with experiments quite well. For small transport current, the approximate explicit expressions of sheet current, flux-density and penetration depth for the Kim model are derived based on the mean value theorem for integration. We also extend the results to the field-dependent critical state of superconducting strip in the simultaneous presence of applied field and transport current. The sheet current distributions calculated by the Kim model agree with experiments better than that by the Bean model. Moreover, the lines in the Ia-Ba plane for the Kim model are not monotonic, which is quite different from that the Bean model. The results reveal that the maximum transport current in thin superconducting strip will decrease with increasing applied field which vanishes for the Bean model. The results of this paper are useful to calculate ac susceptibility and ac loss.

  13. Field-dependent critical state of high-Tc superconducting strip simultaneously exposed to transport current and perpendicular magnetic field

    Directory of Open Access Journals (Sweden)

    Cun Xue

    2013-12-01

    Full Text Available We present an exact analytical approach for arbitrary field-dependent critical state of high-Tc superconducting strip with transport current. The sheet current and flux-density profiles are derived by solving the integral equations, which agree with experiments quite well. For small transport current, the approximate explicit expressions of sheet current, flux-density and penetration depth for the Kim model are derived based on the mean value theorem for integration. We also extend the results to the field-dependent critical state of superconducting strip in the simultaneous presence of applied field and transport current. The sheet current distributions calculated by the Kim model agree with experiments better than that by the Bean model. Moreover, the lines in the Ia-Ba plane for the Kim model are not monotonic, which is quite different from that the Bean model. The results reveal that the maximum transport current in thin superconducting strip will decrease with increasing applied field which vanishes for the Bean model. The results of this paper are useful to calculate ac susceptibility and ac loss.

  14. High Tc thin film superconductors: preparation, patterning and characterization. [Y-Ba-Cu-O; Bi-Sr-Ca-Cu-O

    Energy Technology Data Exchange (ETDEWEB)

    Azoulay, J. (Center for Tech. Education, Holon (Israel) Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel-Aviv Univ. (Israel))

    1991-12-10

    A conventional oil-pumped vacuum system equipped with resistively heated tungsten boat sources was used for evaporation of bismuth- or yttrium-based cuprates for high Tc thin films superconductors. A well-ground mixture with atomic proportions of bismuth, SrF{sub 2}, CaF{sub 2} and copper for bismuth-based material, and of YF{sub 3}, BaF{sub 2} and copper for yttrium-based material, was inserted into the boat and then resistively evaporated onto different substrates such as MgO, ZrO{sub 2} and SrTiO{sub 3} kept at room temperature. Yttrium-based thin films were found to have a better quality upon reduction of fluorine in the constituents. Thus, films prepared with an yttrium BaF{sub 2} and copper mixture show a metallic-like behaviour, sharper transition and higher zero-resistance temperature as compared with that of films obtained by using a YF{sub 2} constituent instead of yttrium. Bismuth-based thin films were found to lose bismuth during heat treatment unless the copper constituent ended the evaporation process and was subsequently fully oxidized at 400degC. Bismuth-based patterned films were easily obtained by using a lift-off photolithographic method. Typical thickness of the films was measured to be about 0.5 {mu}m after heat treatment. (orig.).

  15. Expedient multi-step synthesis of organometallic complexes of Tc and Re in high effective specific activity. A new platform for the production of molecular imaging and therapy agents.

    Science.gov (United States)

    Causey, Patrick W; Besanger, Travis R; Schaffer, Paul; Valliant, John F

    2008-09-15

    For over thirty years, instant labeling kits which involve no purification steps have been the only method used to prepare (99m)Tc radiopharmaceuticals for clinical studies. To address the limitations imposed by instant kits, which is hindering the development of molecularly targeted Tc- and Re-based imaging and therapy agents, a new strategy for the rapid multistep synthesis and purification of organometallic technetium-based molecular probes and corresponding rhenium-based therapeutic analogues was developed. Beginning with MO4(-) (M = (99m)Tc, (186/188)Re), the carbonyl precursor [M(CO)3(H2O)3](+) was synthesized in 3 min in quantitative yield in a microwave reactor. A dipicolyl ligand was added and the chelate complex was formed in high yield in 2 min using microwave heating at 150 degrees C. This was followed by a new purification strategy to remove unlabeled ligand which entailed using a copper resin/C18 solid phase extraction protocol giving the desired product in greater than 78% decay corrected yield (dcy). Conversion to the corresponding succinimidyl active ester was achieved following a 5 min microwave irradiation at 120 degrees C and C18 solid phase extraction purification in 60% dcy. A series of amides were prepared subsequently by microwave heating at 120 degrees C for 5 min producing the desired targets in greater than 86% dcy. The reported method represents a move away from traditional instant kits toward more versatile platform synthesis and purification technologies that are better suited for producing modern molecular imaging and therapy agents.

  16. Compressed H3S: inter-sublattice Coulomb coupling in a high-TC superconductor.

    Science.gov (United States)

    Harshman, Dale R; Fiory, Anthony T

    2017-07-19

    Upon thermal annealing at or above room temperature (RT) and at high hydrostatic pressure P ~ 155 GPa, sulfur trihydride H3S exhibits a measured maximum superconducting transition temperature TC ~ 200 K. Various theoretical frameworks incorporating strong electron-phonon coupling and Coulomb repulsion have reproduced this record-level TC. Of particular relevance is that experimentally observed H-D isotopic correlations among TC, P, and annealed order indicate an H-D isotope effect exponent α limited to values ≤ 0.183, leaving open for consideration unconventional high-TC superconductivity with electronic-based enhancements. The work presented herein examines Coulombic pairing arising from interactions between neighboring S and H species on separate interlaced sublattices constituting H3S in the Im3m structure. The optimal value of the transition temperature is calculated from TC0 = kB-1Λe2/ℓζ, with Λ = 0.007465 Å, inter-sublattice S-H separation spacing ζ = a0/√2, interaction charge linear spacing ℓ = a0 (3/σ)1/2, average participating charge fraction σ = 3.43 ± 0.10 estimated from calculated H-projected electron states, and lattice parameter a0 = 3.0823 Å at P = 155 GPa. The resulting value of TC0 = 198.5 ± 3.0 K is in excellent agreement with transition temperatures determined from resistivity (196 - 200 K onsets, 190 - 197 K midpoints), susceptibility (200 K onset), and critical magnetic fields (203.5 K by extrapolation). Analysis of mid-infrared reflectivity data confirms the expected correlation between boson energy and ζ-1. Suppression of TC below

  17. Emerging Diluted Ferromagnetism in High-Tc Superconductors Driven by Point Defect Clusters.

    Science.gov (United States)

    Gazquez, Jaume; Guzman, Roger; Mishra, Rohan; Bartolomé, Elena; Salafranca, Juan; Magén, Cesar; Varela, Maria; Coll, Mariona; Palau, Anna; Valvidares, S Manuel; Gargiani, Pierluigi; Pellegrin, Eric; Herrero-Martin, Javier; Pennycook, Stephen J; Pantelides, Sokrates T; Puig, Teresa; Obradors, Xavier

    2016-06-01

    Defects in ceramic materials are generally seen as detrimental to their functionality and applicability. Yet, in some complex oxides, defects present an opportunity to enhance some of their properties or even lead to the discovery of exciting physics, particularly in the presence of strong correlations. A paradigmatic case is the high-temperature superconductor YBa2Cu3O7-δ (Y123), in which nanoscale defects play an important role as they can immobilize quantized magnetic flux vortices. Here previously unforeseen point defects buried in Y123 thin films that lead to the formation of ferromagnetic clusters embedded within the superconductor are unveiled. Aberration-corrected scanning transmission microscopy has been used for exploring, on a single unit-cell level, the structure and chemistry resulting from these complex point defects, along with density functional theory calculations, for providing new insights about their nature including an unexpected defect-driven ferromagnetism, and X-ray magnetic circular dichroism for bearing evidence of Cu magnetic moments that align ferromagnetically even below the superconducting critical temperature to form a dilute system of magnetic clusters associated with the point defects.

  18. A magnetic levitation rotating plate model based on high-Tc superconducting technology

    Science.gov (United States)

    Zheng, Jun; Li, Jipeng; Sun, Ruixue; Qian, Nan; Deng, Zigang

    2017-09-01

    With the wide requirements of the training aids and display models of science, technology and even industrial products for the public like schools, museums and pleasure grounds, a simple-structure and long-term stable-levitation technology is needed for these exhibitions. Opportunely, high temperature superconducting (HTS) technology using bulk superconductors indeed has prominent advantages on magnetic levitation and suspension for its self-stable characteristic in an applied magnetic field without any external power or control. This paper explores the feasibility of designing a rotatable magnetic levitation (maglev) plate model with HTS bulks placed beneath a permanent magnet (PM) plate. The model is featured with HTS bulks together with their essential cryogenic equipment above and PMs below, therefore it eliminates the unclear visual effects by spray due to the low temperature coolant such as liquid nitrogen (LN2) and additional levitation weight of the cryogenic equipment. Besides that, a matched LN2 automation filling system is adopted to help achieving a long-term working state of the rotatable maglev plate. The key low-temperature working condition for HTS bulks is maintained by repeatedly opening a solenoid valve and automatically filling LN2 under the monitoring of a temperature sensor inside the cryostat. With the support of the cryogenic devices, the HTS maglev system can meet all requirements of the levitating display model for exhibitions, and may enlighten the research work on HTS maglev applications.

  19. Progress in Neutron Scattering Studies of Spin Excitations in High-Tc Cuprates

    Science.gov (United States)

    Fujita, Masaki; Hiraka, Haruhiro; Matsuda, Masaaki; Matsuura, Masato; Tranquada, John M.; Wakimoto, Shuichi; Xu, Guangyong; Yamada, Kazuyoshi

    2012-01-01

    Neutron scattering experiments continue to improve our knowledge of spin fluctuations in layered cuprates, excitations that are symptomatic of the electronic correlations underlying high-temperature superconductivity. Time-of-flight spectrometers, together with new and varied single crystal samples, have provided a more complete characterization of the magnetic energy spectrum and its variation with carrier concentration. While the spin excitations appear anomalous in comparison with simple model systems, there is clear consistency among a variety of cuprate families. Focusing initially on hole-doped systems, we review the nature of the magnetic spectrum, and variations in magnetic spectral weight with doping. We consider connections with the phenomena of charge and spin stripe order, and the potential generality of such correlations as suggested by studies of magnetic-field and impurity induced order. We contrast the behavior of the hole-doped systems with the trends found in the electron-doped superconductors. Returning to hole-doped cuprates, studies of translation-symmetry-preserving magnetic order are discussed, along with efforts to explore new systems. We conclude with a discussion of future challenges.

  20. Phonon characteristics of high {Tc} superconductors from neutron Doppler broadening measurements

    Energy Technology Data Exchange (ETDEWEB)

    Trela, W.J.; Kwei, G.H.; Lynn, J.E. [Los Alamos National Lab., NM (United States); Meggers, K. [Univ. of Kiel (Germany)

    1994-12-01

    Statistical information on the phonon frequency spectrum of materials can be measured by neutron transmission techniques if they contain nuclei with low energy resonances, narrow enough to be Doppler-broadened, in their neutron cross sections. The authors have carried out some measurements using this technique for materials of the lanthanum barium cuprate class, La{sub 2{minus}x}Ba{sub x}CuO{sub 4}. Two samples with slightly different concentrations of oxygen, one being superconductive, the other not, were examined. Pure lanthanum cuprate was also measured. Lanthanum, barium and copper all have relatively low energy narrow resonances. Thus it should be possible to detect differences in the phonons carried by different kinds of atom in the lattice. Neutron cross section measurements have been made with high energy resolution and statistical precision on the 59m flight path of LANSCE, the pulsed spallation neutron source at Los Alamos National Laboratory. Measurements on all three materials were made over a range of temperatures from 15K to 300K, with small steps through the critical temperature region near 27K. No significant changes in the mean phonon energy of the lanthanum atoms were observed near the critical temperature of the super-conducting material. It appears however that the mean phonon energy of lanthanum in the superconductor is considerably higher than that in the non-superconductors. The samples used in this series of experiments were too thin in barium and copper to determine anything significant about their phonon spectra.

  1. Design report of Task 7.5, High-Tc Link

    CERN Document Server

    Ballarino, A

    2012-01-01

    The proposal of developing High Temperature Superconducting (HTS) cables derives from the potential of the application of HTS in the powering system of the LHC accelerator [1]. The powering of the LHC magnets is today performed via power converters located in tunnel alcoves. Warm cables connect the power converters to the leads integrated in cryostats in line with the beam. The use of superconducting links allows the removal of the powering equipment from the radiation areas in the tunnel to remote radiation-free locations. As a result, one can ensure safer long-term operation of the equipment as well as easier access - in non radiation zones - of personnel to power converters, current leads and related control apparatus for the maintenance, repair, diagnostic and other interventions. The FP7 activity performed within the Task 7.5 aims at the development of a superconducting link of the type that could be applied in the LHC at P3 or P7. It consists of 48 cables, rated at 600 A – DC, and developed for the po...

  2. High Density, Insensitive Oxidizer With RDX Performance Final Report CRADA No. TC02178.0

    Energy Technology Data Exchange (ETDEWEB)

    Pagoria, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Preda, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-25

    This was a collaborative effort between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and Physical Sciences, Inc. (PSI), to develop a synthesis and evaluate a novel high density, insensitive oxidizer with RDX performance. This CRADA resulted from the award of a Phase I STTR ("STTR") from DOD. In recent years, the synthesis of new energetic heterocyclic compounds to replace the energetic materials currently in the stockpile has received a great amount of attention. The Office of the Secretary of Defense has identified that there is a need to incorporate new energetic materials in current and future weapon systems in an effort to increase performance and decrease sensitivity. For many of the future weapon systems, incorporation of energetic compounds currently in the stockpile will not provide the desired performance and sensitivity goals. The success of this CRADA may lead to a Phase I option STTR from DOD and to a Phase II STTR from DOD. The goal of this CRADA was to produce and test a novel oxidizer, 2,5,8-trinitroheptazine (TNH).

  3. A study of fabrication and properties of high-Tc superconductor tapes

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Jin Ho; Ji, Bong Ki; Kim, Tae Woo [Sungkyunkwan University, Seoul (Korea, Republic of)

    1997-07-01

    Superconductor tape with improved electrical and mechanical properties is needed for the application of high technology equipments. To this end, we evaluated the effects of processing variables on interface irregularity, microstructure, and resultant J{sub c} of tape. For the tapes made by PIT technique, the degree of interface irregularity was varied with powder packing methods and forming process variables. It was observed that the degree of interface irregularity of tapes by CIP method was more reduced, compared to that of tape by ram method. In addition, the degree of interface irregularity was promoted with decreasing the dimension of tape during forming process. As the dimension of wire/tape were changed from diameter of 3.25 mm to thickness of 0.20 mm during forming process, J{sub c} value, were observed to be increased by 10 times. It was likely that the improvement of J{sub c} was mainly result from the enhanced texturing of 2223 grain. Microstructural investigation showed the degree of texturing were degraded by the existence of both second phases and interface irregularity. If the interface were glat, larger grain size and better texturing near interface were developed compared to those inside superconducting core. The improvements of microstructure near interface may be result o reaction between Ag and superconductor phase. 23 refs., 15 figs. (author)

  4. Nodal Liquid Theory of the Pseudo-Gap Phase of High-Tc Superconductors

    Science.gov (United States)

    Balents, Leon; Fisher, Matthew P. A.; Nayak, Chetan

    We introduce and study the nodal liquid, a novel zero-temperature quantum phase obtained by quantum-disordering a d-wave superconductor. It has numerous remarkable properties which lead us to suggest it as an explanation of the pseudo-gap state in underdoped high-temperature superconductors. In the absence of impurities, these include power-law magnetic order, a T-linear spin susceptibility, nontrivial thermal conductivity, and two- and one-particle charge gaps, the latter evidenced, e.g. in transport and electron photoemission (which exhibits pronounced fourfold anisotropy inherited from the d-wave quasiparticles). We use a (2+1)-dimensional duality transformation to derive an effective field theory for this phase. The theory is comprised of gapless neutral Dirac particles living at the former d-wave nodes, weakly coupled to the fluctuating gauge field of a dual Ginzburg-Landau theory. The nodal liquid interpolates naturally between the d-wave superconductor and the insulating antiferromagnet, and our effective field theory is powerful enough to permit a detailed analysis of a panoply of interesting phenomena, including charge ordering, antiferromagnetism, and d-wave superconductivity. We also discuss the zero-temperature quantum phase transitions which separate the nodal liquid from various ordered phases.

  5. MAGLEV: The double benefits of high-Tc superconductors and its development as an aerospace technology

    Science.gov (United States)

    Johnson, L. R.; Giese, R. F.

    1988-04-01

    The potential for magnetically levitated (MAGLEV) vehicles is discussed as a means of both inter-city travel and a technology option to relieve the growing problem of air traffic congestion. A brief summary is presented of the two primary MAGLEV concepts: (1) the attractive-force, electromagnetic system (EMS) and (2) the repulsive-force, electrodynamic system (EDS), and continues with a discussion of the advantages, potential for reduced costs and higher reliability, that the newly-discovered, high-temperature superconductors offer for EDS MAGLEV vehicles. A summary of the current status of worldwide MAGLEV research is presented, followed by a discussion of the resurgence of US interest in MAGLEV. An analysis of air-traffic congestion suggests that MAGLEV can substitute for short-to-medium distance air travel. By promoting MAGLEV as an airline technology, airlines can retain their familiar hub-and-spoke systems with MAGLEVs an integral part of the spoke portion. A preliminary analysis suggests that MAGLEV capital costs are likely to be comparable to those of interstate highways, and use of MAGLEVs can delay the need for new airport construction. For each short-to-medium flight diverted to MAGLEV, an airline can substitute a longer flight. The short-haul flights use an inordinate amount of fuel, which is a major component of airline operating costs. MAGLEV energy consumption would be significantly less and would not have the emissions associated with petroleum fuel. Finally, passengers should benefit from MAGLEV technology: travel options will be extended, delays will be reduced, and costs for inter-city travel will be reduced.

  6. High Tc superconductors: The scaling of Tc with the number of bound holes associated with charge transfer neutralizing the multivalence cations

    Science.gov (United States)

    Vezzoli, G. C.; Chen, M. F.; Craver, F.

    1991-01-01

    It is observed that for the known high-T(sub c) Cu-, Tl-, and Bi-based superconductors, T(sub c) scales consistently with the number of bound holes per unit cell which arise from charge transfer excitations of frequency approximately = 3 x 10(exp 13) that neutralized the multivalence cations into diamagnetic states. The resulting holes are established on the oxygens. Extrapolation of this empirical fit in the up-temperature direction suggests a T(sub c) of about 220-230 K at a value of 25 holes/unit cell (approximately the maximum that can be materials-engineered into a high-T(sub c) K2MnF4 or triple Perovskite structure). In the down-temperature direction, the extrapolation gives a T(sub c) in the vicinity of 235 K for the Y-Ba-Cu-O system as well as the known maximum temperature of 23 K for low-T(sub c) materials shown by Nb3Ge. The approach is also consistent with the experimental findings that only multivalence ions which are diamagnetic in their atomic state (Cu, Tl, Bi, Pb, and Sb) associate with high-T(sub c) compounds.

  7. Highly Selective Colorimetric and Luminescence Response of a Square-Planar Platinum(II) Terpyridyl Complex to Aqueous TcO4-

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Sayandev; Norton, Amie E.; Edwards, Matthew K.; Peterson, James M.; Taylor, Stephen D.; Bryan, Samuel A.; Andersen, Amity; Govind, Niranjan; Albrecht-Schmitt, Thomas E.; Connick, William; Levitskaia, Tatiana G.

    2015-10-08

    In an effort to address the need for a rapid, selective and economical detection technique for aqueous pertechnetate (TcO4-) anion based on recognition at the molecular level, simple salts of transition metal complexes that undergo a distinct spectroscopic change upon exposure to aqueous anions were explored. The Pt(II) complex [Pt(tpy)Br]SbF6 (tpy=2,2';6',2"-terpyridine) undergoes a dramatic color change and intense luminescence response upon TcO4- uptake due to concomitant enhancement of Pt•••Pt interactions. The spectroscopic response was highly selective and quantitative for aqueous TcO4- among other competing anions. Complimentary Raman spectroscopy and microscopy techniques, structural determination and theoretical methods were employed to achieve molecular-level understanding of the mechanism of the response to aqueous TcO4-.

  8. Milking technique of sup(99m)Tc generators and labeling efficiencies

    Energy Technology Data Exchange (ETDEWEB)

    Salehi, N.; Guignard, P.A. (Royal Melbourne Hospital, Parkville (Australia). Dept. of Nuclear Medicine)

    1985-05-01

    Increased levels of /sup 99/Tc in generator produced sup(99m)Tc have an adverse effect on the labelling efficiency of red blood cells and human serum albumin. A two-step milking technique in which the first 1-2 ml of eluate is discarded has been found to produce higher and more constant labelling efficiency of lymphocytes and platelets than a one-step procedure. Binding efficiency of platelet-rich plasma and lymphocytes with sup(99m)Tc is greater in the two-step technique. High activity concentration in the eluate for critical labelling is between 1.5-3 ml.

  9. Synthesis of colloidal Mn2+:ZnO quantum dots and high-TC ferromagnetic nanocrystalline thin films.

    Science.gov (United States)

    Norberg, Nick S; Kittilstved, Kevin R; Amonette, James E; Kukkadapu, Ravi K; Schwartz, Dana A; Gamelin, Daniel R

    2004-08-04

    We report the synthesis of colloidal Mn(2+)-doped ZnO (Mn(2+):ZnO) quantum dots and the preparation of room-temperature ferromagnetic nanocrystalline thin films. Mn(2+):ZnO nanocrystals were prepared by a hydrolysis and condensation reaction in DMSO under atmospheric conditions. Synthesis was monitored by electronic absorption and electron paramagnetic resonance (EPR) spectroscopies. Zn(OAc)(2) was found to strongly inhibit oxidation of Mn(2+) by O(2), allowing the synthesis of Mn(2+):ZnO to be performed aerobically. Mn(2+) ions were removed from the surfaces of as-prepared nanocrystals using dodecylamine to yield high-quality internally doped Mn(2+):ZnO colloids of nearly spherical shape and uniform diameter (6.1 +/- 0.7 nm). Simulations of the highly resolved X- and Q-band nanocrystal EPR spectra, combined with quantitative analysis of magnetic susceptibilities, confirmed that the manganese is substitutionally incorporated into the ZnO nanocrystals as Mn(2+) with very homogeneous speciation, differing from bulk Mn(2+):ZnO only in the magnitude of D-strain. Robust ferromagnetism was observed in spin-coated thin films of the nanocrystals, with 300 K saturation moments as large as 1.35 micro(B)/Mn(2+) and T(C) > 350 K. A distinct ferromagnetic resonance signal was observed in the EPR spectra of the ferromagnetic films. The occurrence of ferromagnetism in Mn(2+):ZnO and its dependence on synthetic variables are discussed in the context of these and previous theoretical and experimental results.

  10. High-Tc and high-Jc SmFeAs(O,F) films on fluoride substrates grown by molecular beam epitaxy

    Science.gov (United States)

    Ueda, Shinya; Takeda, Soichiro; Takano, Shiro; Yamamoto, Akiyasu; Naito, Michio

    2011-12-01

    Superconducting thin films of SmFeAs(O,F) were prepared by molecular beam epitaxy on fluoride substrates. In our process, F-free SmFeAsO films were grown first, and F was subsequently introduced to the films by diffusion from an overlayer of SmF3. By this simple process, record high Tc, namely, Tcon (Tcend) = 57.8 K (56.4 K) was obtained in a film on CaF2. Furthermore, the films on CaF2 showed high critical current density over 1 MA/cm2 in the self-field at 5 K. The correlation between superconductivity and epitaxial strain in SmFeAs(O,F) films is discussed.

  11. Probabilistic assessment for the design of high reliability objects (greater than 0.999) such as solid propellant grains

    Science.gov (United States)

    Nahon, S.; Silvestrini, P.; Thepenier, J.

    1992-07-01

    A Bayesian method is proposed which uses the safety margin to justify the design of high-reliability objects characterized by one-shot destructive functioning and by a high manufacturing cost. To validate the Bayesian reliability model, a program of overtests has been conducted with seven solid propellant grains of six tons each. Each trial has been performed with a reduced safety margin leading to a design reliability of 0.5 at 60 percent confidence level. The reliability model gives reasonably good agreement with experimental results as the confidence level stabilizes, leading to the conclusion that it can be applied to estimate higher reliability levels (greater than 0.999).

  12. Structural changes of high-Tc superconductors under pressures up to 29 GPa and at temperatures between 15 and 300 K

    Science.gov (United States)

    Fietz, W. H.; Wassilew, C. A.; Ludwig, H. A.; Obst, B.; Dietrich, M. R.

    1990-05-01

    Structural changes in the high-Tc superconductors YbBa2Cu3O7 (Yb-123) and Yb2BaCuO5 (Yb-211) with increasing pressure are studied using self-focusing X-ray equipment with a position-sensitive detector. The results show that Yb-123 has a bulk modulus of 155 GPa with linear compressibilities beta(a) = 0.0013/GPa, beta(b) = 0.0015/GPa, and beta(c) = 0.0033/GPa. The bulk modulus of superconducting Yb-211 is 170 GPa. Similar measurements on several other high-Tc superconductors and related materials show a systematic decrease of the bulk modulus of high-Tc superconductors when going from materials closely related to perovskite to materials with an extremely degenerated perovskite structure. This change is mainly caused by a change of the linear compressibility in the c-axis direction. The linear compressibilities in the a and b directions are similar for all these materials.

  13. Greater Melbourne.

    Science.gov (United States)

    Wulff, M; Burke, T; Newton, P

    1986-03-01

    With more than a quarter of its population born overseas, Melbourne, Australia, is rapidly changing from an all-white British outpost to a multicultural, multilingual community. Since the "white" Australian policy was abandoned after World War II, 3 million immigrants from 100 different countries have moved to Australia. Most of the immigrants come from New Zealand, Rhodesia, South Africa, Britain, Ireland, Greece, Turkey, Yugoslavia, Poland, and Indochina. Melbourne is Australia's 2nd largest city and houses 1 out of 5 Australians. Its 1984 population was 2,888,400. Melbourne's housing pattern consists of subdivisions; 75% of the population live in detached houses. Between 1954 and 1961 Melbourne grew at an annual rate of 3.5%; its growth rate between 1961 and 1971 still averaged 2.5%. In the 1970s the growth rate slowed to 1.4%. Metropolitan Melbourne has no central government but is divided into 56 councils and 8 regions. Both Australia's and Melbourne's fertility rates are high compared to the rest of the developed world, partly because of their younger age structure. 41% of Melbourne's population was under age 24 in 1981. Single-person households are growing faster than any other type. 71% of the housing is owner-occupied; in 1981 the median sized dwelling had 5.2 rooms. Public housing only accounts for 2.6% of all dwellings. Fewer students graduate from high school in Australia than in other developed countries, and fewer graduates pursue higher education. Melbourne's suburban sprawl promotes private car travel. In 1980 Melbourne contained more than 28,000 retail establishments and 4200 restaurants and hotels. Industry accounts for 30% of employment, and services account for another 30%. Its largest industries are motor vehicles, clothing, and footware. Although unemployment reached 10% after the 1973 energy crisis, by 1985 it was down to 6%.

  14. Possible field-tuned superconductor-insulator transition in high-Tc superconductors: implications for pairing at high magnetic fields.

    Science.gov (United States)

    Steiner, M A; Boebinger, G; Kapitulnik, A

    2005-03-18

    The behavior of some high temperature superconductors (HTSC), such as La(2-x)Sr(x)CuO(4) and Bi(2)Sr(2-x)La(x)CuO(6 + delta), at very high magnetic fields, is similar to that of thin films of amorphous InOx near the magnetic-field-tuned superconductor-insulator transition. Analyzing the InOx data at high fields in terms of persisting local pairing amplitude, we argue by analogy that the local pairing amplitude also persists well into the dissipative state of the HTSCs, the regime commonly denoted as the "normal state" in very high magnetic field experiments.

  15. Different fibrovascularization rate between coralline hydroxyapatite and high density porous polyethylene (Medpore) measured by 99mTc-MDP bone scintigraphy 6 months after intraorbital implantation.

    Science.gov (United States)

    Pan, M-H; Wu, Y-W; Yen, R-F; Tzen, K-Y; Liao, S-L; Kao, C-H

    2003-12-01

    Many materials and types of implant have been used to achieve a cosmetic effect and prosthesis motility in the anophthalmic socket. Hydroxyapatite remains the implant material of choice for producing the most natural prosthesis motility while porous polyethylene shows promising characteristics as another useful material. The aim of this study was to compare the fibrovascular ingrowth rates of orbital implants between coralline hydroxyapatite and high density porous polyethylene (Medpore). The fibrovascularization rate is determined by bone imaging using 99mTc methylene diphosphonate (99mTc-MDP) 6 months after implantation. Our study included 29 patients with coralline, and nine patients with Medpore implants. Our results showed that groups with coralline implants appearing to achieve complete fibrovascularization at a much more rapid rate than those with Medpore. The differences in rate were statistically significant.

  16. Systemic Oxidative Stress Is Increased to a Greater Degree in Young, Obese Women Following Consumption of a High Fat Meal

    Directory of Open Access Journals (Sweden)

    Richard J. Bloomer

    2009-01-01

    Full Text Available High fat meals induce oxidative stress, which is associated with the pathogenesis of disease. Obese individuals have elevated resting biomarkers of oxidative stress compared to non-obese. We compared blood oxidative stress biomarkers in obese (n = 14; 30 ± 2 years; BMI 35 ± 1 kg•m−2 and non-obese (n = 16; 24 ± 2 years; BMI 23 ± 1 kg•m−2 women, in response to a high fat meal. Blood samples were collected pre-meal (fasted, and at 1, 2, 4 and 6 hours post meal, and assayed for trolox equivalent antioxidant capacity (TEAC, xanthine oxidase activity (XO, hydrogen peroxide (H2O2, malondialdehyde (MDA, triglycerides (TAG, and glucose. An obesity status effect was noted for all variables (p 0.05, contrasts revealed greater values in obese compared to non-obese women for XO, H2O2, MDA, TAG and glucose, and lower values for TEAC at times from 1–6 hours post feeding (p ≤ 0.03. We conclude that young, obese women experience a similar pattern of increase in blood oxidative stress biomarkers in response to a high fat meal, as compared to non-obese women. However, the overall oxidative stress is greater in obese women, and values appear to remain elevated for longer periods of time post feeding. These data provide insight into another potential mechanism related to obesity-mediated morbidity.

  17. Large-moment antiferromagnetic order in overdoped high-Tc superconductor 154SmFeAsO1-xDx

    Science.gov (United States)

    Iimura, Soshi; Okanishi, Hiroshi; Matsuishi, Satoru; Hiraka, Haruhiro; Honda, Takashi; Ikeda, Kazutaka; Hansen, Thomas C.; Otomo, Toshiya; Hosono, Hideo

    2017-05-01

    In iron-based superconductors, high critical temperature (Tc) superconductivity over 50 K has only been accomplished in electron-doped hREFeAsO (hRE is heavy rare earth (RE) element). Although hREFeAsO has the highest bulk Tc (58 K), progress in understanding its physical properties has been relatively slow due to difficulties in achieving high-concentration electron doping and carrying out neutron experiments. Here, we present a systematic neutron powder diffraction study of 154SmFeAsO1-xDx, and the discovery of a long-range antiferromagnetic ordering with x ≥ 0.56 (AFM2) accompanying a structural transition from tetragonal to orthorhombic. Surprisingly, the Fe magnetic moment in AFM2 reaches a magnitude of 2.73 μB/Fe, which is the largest in all nondoped iron pnictides and chalcogenides. Theoretical calculations suggest that the AFM2 phase originates in kinetic frustration of the Fe-3dxy orbital, in which the nearest-neighbor hopping parameter becomes zero. The unique phase diagram, i.e., highest-Tc superconducting phase adjacent to the strongly correlated phase in electron-overdoped regime, yields important clues to the unconventional origins of superconductivity.

  18. Preparation, structure and superconductivity of high T(c) compounds: Research of high temperature superconductors in Hungary

    Science.gov (United States)

    Kirschner, I.

    1995-01-01

    In this paper the main directions, methods and results of the investigation of high-T(c) superconductors in Hungary are briefly summarized. The fundamental idea of this research is to study the effect of starting conditions on the microstructure of samples and the influence of the latter one on their superconducting parameters. The investigation concerning technical development is also mentioned.

  19. Polarized training has greater impact on key endurance variables than threshold, high intensity or high volume training

    Directory of Open Access Journals (Sweden)

    Thomas eStöggl

    2014-02-01

    Full Text Available Endurance athletes integrate four conditioning concepts in their training programs: high-volume training (HVT, ‘threshold-training’ (THR, high-intensity interval training (HIIT and a combination of these aforementioned concepts known as polarized training (POL. The purpose of this study was to explore which of these four training concepts provides the greatest response on key components of endurance performance in well-trained endurance athletes. Methods: Forty eight runners, cyclists, triathletes and cross-country skiers (peak oxygen uptake: (VO2peak: 62.6±7.1 mL∙min-1∙kg-1 were randomly assigned to one of four groups performing over nine weeks. An incremental test, work economy and a VO2peak tests were performed. Training intensity was heart rate controlled. Results: POL demonstrated the greatest increase in VO2peak (+6.8 ml∙min∙kg-1 or 11.7%, P0.05. Conclusion: POL resulted in the greatest improvements in most key variables of endurance performance in well-trained endurance athletes. THR or HVT did not lead to further improvements in performance related variables.

  20. Novel Interplay between High-Tc Superconductivity and Antiferromagnetism in Tl-Based Six-CuO2-Layered Cuprates: 205Tl- and 63Cu-NMR Probes

    Science.gov (United States)

    Mukuda, Hidekazu; Shiki, Nozomu; Kimoto, Naoki; Yashima, Mitsuharu; Kitaoka, Yoshio; Tokiwa, Kazuyasu; Iyo, Akira

    2016-08-01

    We report 63Cu- and 205Tl-NMR studies on six-layered (n = 6) high-Tc superconducting (SC) cuprate TlBa2Ca5Cu6O14+δ (Tl1256) with Tc ˜ 100 K, which reveal that antiferromagnetic (AFM) order takes place below TN ˜ 170 K. In this compound, four underdoped inner CuO2 planes [n(IP) = 4] sandwiched by two outer planes (OPs) are responsible for the onset of AFM order, whereas the nearly optimally-doped OPs responsible for the onset of bulk SC. It is pointed out that an increase in the out-of-plane magnetic interaction within an intra-unit-cell causes TN ˜ 45 K for Tl1245 with n(IP) = 3 to increase to ˜170 K for Tl1256 with n(IP) = 4. It is remarkable that the marked increase in TN and the AFM moments for the IPs does not bring about any reduction in Tc, since Tc ˜ 100 K is maintained for both compounds with nearly optimally doped OP. We highlight the fact that the SC order for n ≥ 5 is mostly dominated by the long-range in-plane SC correlation even in the multilayered structure, which is insensitive to the magnitude of TN and the AFM moments at the IPs or the AFM interaction among the IPs. These results demonstrate a novel interplay between the SC and AFM orders when the charge imbalance between the IPs and OP is significantly large.

  1. Facilitation in Caribbean coral reefs: high densities of staghorn coral foster greater coral condition and reef fish composition.

    Science.gov (United States)

    Huntington, Brittany E; Miller, Margaret W; Pausch, Rachel; Richter, Lee

    2017-05-01

    Recovery of the threatened staghorn coral (Acropora cervicornis) is posited to play a key role in Caribbean reef resilience. At four Caribbean locations (including one restored and three extant populations), we quantified characteristics of contemporary staghorn coral across increasing conspecific densities, and investigated a hypothesis of facilitation between staghorn coral and reef fishes. High staghorn densities in the Dry Tortugas exhibited significantly less partial mortality, higher branch growth, and supported greater fish abundances compared to lower densities within the same population. In contrast, partial mortality, branch growth, and fish community composition did not vary with staghorn density at the three other study locations where staghorn densities were lower overall. This suggests that density-dependent effects between the coral and fish community may only manifest at high staghorn densities. We then evaluated one facilitative mechanism for such density-dependence, whereby abundant fishes sheltering in dense staghorn aggregations deliver nutrients back to the coral, fueling faster coral growth, thereby creating more fish habitat. Indeed, dense staghorn aggregations within the Dry Tortugas exhibited significantly higher growth rates, tissue nitrogen, and zooxanthellae densities than sparse aggregations. Similarly, higher tissue nitrogen was induced in a macroalgae bioassay outplanted into the same dense and sparse aggregations, confirming greater bioavailability of nutrients at high staghorn densities. Our findings inform staghorn restoration efforts, suggesting that the most effective targets may be higher coral densities than previously thought. These coral-dense aggregations may reap the benefits of positive facilitation between the staghorn and fish community, favoring the growth and survivorship of this threatened species.

  2. Wide-pulse-high-frequency neuromuscular stimulation of triceps surae induces greater muscle fatigue compared with conventional stimulation.

    Science.gov (United States)

    Neyroud, Daria; Dodd, David; Gondin, Julien; Maffiuletti, Nicola A; Kayser, Bengt; Place, Nicolas

    2014-05-15

    We compared the extent and origin of muscle fatigue induced by short-pulse-low-frequency [conventional (CONV)] and wide-pulse-high-frequency (WPHF) neuromuscular electrical stimulation. We expected CONV contractions to mainly originate from depolarization of axonal terminal branches (spatially determined muscle fiber recruitment) and WPHF contractions to be partly produced via a central pathway (motor unit recruitment according to size principle). Greater neuromuscular fatigue was, therefore, expected following CONV compared with WPHF. Fourteen healthy subjects underwent 20 WPHF (1 ms-100 Hz) and CONV (50 μs-25 Hz) evoked isometric triceps surae contractions (work/rest periods 20:40 s) at an initial target of 10% of maximal voluntary contraction (MVC) force. Force-time integral of the 20 evoked contractions (FTI) was used as main index of muscle fatigue; MVC force loss was also quantified. Central and peripheral fatigue were assessed by voluntary activation level and paired stimulation amplitudes, respectively. FTI in WPHF was significantly lower than in CONV (21,717 ± 11,541 vs. 37,958 ± 9,898 N·s P 0.05). Overall, our results showed a different motor unit recruitment pattern between the two neuromuscular electrical stimulation modalities with a lower FTI indicating greater muscle fatigue for WPHF, possibly limiting the presumed benefits for rehabilitation programs.

  3. In-situ deposition of YBCO high-Tc superconducting thin films by MOCVD and PE-MOCVD

    Science.gov (United States)

    Zhao, J.; Noh, D. W.; Chern, C.; Li, Y. Q.; Norris, P. E.; Kear, B.; Gallois, B.

    1991-01-01

    Metal-Organic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T(sub c) greater than 90 K and J(sub c) of approximately 10(exp 4) A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metal-organic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology.

  4. Preparation of high T(c) Tl-Ba-Ca-Cu-O thin films by pulsed laser evaporation and Tl2O3 vapor processing

    Science.gov (United States)

    Johs, B.; Thompson, D.; Ianno, N. J.; Woollam, John A.; Liou, S. H.

    1989-01-01

    Tl-Ba-Ca-Cu-O superconducting thin films with zero-resistance temperatures up to 115 K have been prepared using a Tl2O3 vapor process on Ba-Ca-Cu-O precursor thin films. The Ba-Ca-Cu-O thin films were made by laser deposition on Y-stabilized ZrO2 substrates. This technique minimizes problems caused by the toxicity of Tl2O3, and its subsequent decomposition to the volatile and toxic Tl2O upon heating. Therefore, it may have practical application in the fabrication of high T(c) Tl-Ba-Ca-Cu-O superconducting thin-film devices.

  5. Bond polarons and high-Tc superconductivity in single layer La_(2-x)Sr_xCuO_4: normal state currents and pairing

    CERN Document Server

    Georgiev, Mladen

    2011-01-01

    We use the term "bond polaron" for a phonon coupled entity which makes the link between neighboring conductive CuO_2 layers in high-Tc superconductive materials. The link is essential for the superconductivity which requires a long range phase coherence in addition to pairing of carriers. The linkage features studied point to a process which is less dependent on the doped hole density implanted as x in the solid solution. The analysis applies to single layered materials mostly but may help understand multilayer ones as well.

  6. Phase 2 Study of (99m)Tc-Trofolastat SPECT/CT to Identify and Localize Prostate Cancer in Intermediate- and High-Risk Patients Undergoing Radical Prostatectomy and Extended Pelvic LN Dissection.

    Science.gov (United States)

    Goffin, Karolien E; Joniau, Steven; Tenke, Peter; Slawin, Kevin; Klein, Eric A; Stambler, Nancy; Strack, Thomas; Babich, John; Armor, Thomas; Wong, Vivien

    2017-09-01

    (99m)Tc-trofolastat ((99m)Tc-MIP-1404), a small-molecule inhibitor of prostate-specific membrane antigen, shows high potential to detect prostate cancer (PCa) noninvasively using SPECT. We therefore wanted to assess the performance of (99m)Tc-trofolastat SPECT/CT in a phase 2 multicenter, multireader prospective study in patients with intermediate- and high-grade PCa, before radical prostatectomy and extended pelvic lymph node (LN) dissection, with histopathology as the gold standard. Methods: PCa patients (n = 105) with an increased risk of LN involvement (LNI) underwent pelvic (99m)Tc-trofolastat SPECT/CT before radical prostatectomy with extended pelvic LN dissection. The sensitivity of (99m)Tc-trofolastat for detection of PCa on a patient and lobe basis, using visual and semiquantitative (tumor-to-background ratio [TBR]) scores, and of LNI was evaluated as well as the correlation of uptake within the gland to Gleason scores (GS) and assessment of the predictive potential of (99m)Tc-trofolastat uptake for LNI. Results: PCa was detected in 98 patients (94%) with acceptable variability between readers. There was a significantly higher visual score and TBR in positive lobes compared with tumor-negative lobes. Receiver-operating characteristic analysis showed that visual scores more accurately discriminated lobes with GS ≤ 3 + 3 from ≥ 3 + 4, whereas TBRs discriminated high-grade disease from normal lobes better. Visual scores and TBRs correlated significantly with GS. (99m)Tc-trofolastat SPECT/CT detected LNI with a sensitivity of 50% and specificity of 87%, and TBR values significantly predicted LNI with a sensitivity of 90%. Conclusion:(99m)Tc-trofolastat SPECT/CT detects PCa with high sensitivity in patients with intermediate- and high-risk PCa compared with histology. It has the potential to be used as a surrogate marker for GS and predict LNI. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

  7. 99mTc-MIBI Lung Scintigraphy in the Assessment of Pulmonary Involvement in Interstitial Lung Disease and Its Comparison With Pulmonary Function Tests and High-Resolution Computed Tomography: A Preliminary Study.

    Science.gov (United States)

    Bahtouee, Mehrzad; Saberifard, Jamshid; Javadi, Hamid; Nabipour, Iraj; Raeisi, Alireza; Assadi, Majid; Eftekhari, Mohammad

    2015-11-01

    The differentiation of active inflammatory processes from an inactive form of the disease is of great value in the management of interstitial lung disease (ILD). The aim of this investigation was to assess the efficacy of 99mTc-methoxy-isobutyl-isonitrile (99mTc-MIBI) scans in distinguishing the severity of the disease compared to radiological and clinical parameters.In total, 19 known cases of ILD were included in this study and were followed up for 1 year. Five patients without lung disease were considered as the control group. The patients underwent pulmonary function tests (PFTs) and high-resolution computed tomography scans, followed by 99mTc-MIBI scanning. The 99mTc-MIBI scans were analyzed either qualitatively (subjectively) or semiquantitatively.All 19 ILD patients demonstrated a strong increase in 99mTc-MIBI uptake in the lungs compared to the control group. The 99mTc-MIBI scan scores were higher in the patient group in both the early phase (0.24[0.19-0.31] vs 0.11[0.10-0.15], P 0.14). The 99mTc-MIBI scan scores were not significantly correlated with the PFT findings (P > 0.05). In total, 5 patients died and 14 patients were still alive over the 1-year follow-up period. There was also a significant difference between the uptake intensity of 99mTc-MIBI and the outcome in the early phase (dead: 0.32[0.29-0.43] vs alive: 0.21[0.18-0.24], P pulmonary involvement in early views, which were well correlated with HRCT findings. These results also revealed that 99mTc-MIBI lung scans might be used as a complement to other diagnostic and clinical examinations in terms of functional information in ILD; however, further investigations are strongly required.

  8. Electron pitch angle variations recorded at the high magnetic latitude boundary layer by the NUADU instrument on the TC-2 spacecraft

    Directory of Open Access Journals (Sweden)

    L. Lu

    2005-11-01

    Full Text Available The NUADU (NeUtral Atom Detector Unit experiment aboard TC-2 recorded, with high temporal and spatial resolution, 4π solid angle images of electrons (~50-125 keV spiraling around geomagnetic field lines at high northern magnetic latitudes (L>10, during its in-orbit commissioning phase (September 2004. The ambient magnetic field, as well as electrons in other energy ranges, were simultaneously measured by the TC-2 magnetometer (FGM, the plasma electron and current experiment (PEACE, the low energy ion detector (LEID and the high energy electron detector (HEED. The NUADU data showed that up-flowing electron beams could form "ring-like" and "dumbbell-type" pitch angle distributions (PADs in the region sampled. Changes in these pitch angle distributions due to transient magnetic variations are suggested to have been associated with electron acceleration along the geomagnetic field lines. A nested magnetic bottle configuration that formed due to the propagation towards the Earth of a magnetic pulse, is proposed to have been associated with this process.

  9. 10 CFR 72.108 - Spent fuel, high-level radioactive waste, or reactor-related greater than Class C waste...

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Spent fuel, high-level radioactive waste, or reactor... RADIOACTIVE WASTE, AND REACTOR-RELATED GREATER THAN CLASS C WASTE Siting Evaluation Factors § 72.108 Spent fuel, high-level radioactive waste, or reactor-related greater than Class C waste transportation. The...

  10. 10 CFR 72.128 - Criteria for spent fuel, high-level radioactive waste, reactor-related greater than Class C waste...

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Criteria for spent fuel, high-level radioactive waste, reactor-related greater than Class C waste, and other radioactive waste storage and handling. 72.128... STORAGE OF SPENT NUCLEAR FUEL, HIGH-LEVEL RADIOACTIVE WASTE, AND REACTOR-RELATED GREATER THAN CLASS C...

  11. 99mTc-ciprofloxacin for diagnosis of bacterial infection

    Science.gov (United States)

    Aungurarat, A.; Ngamprayad, T.; Dangprasert, M.; Phumkem, S.; Jowanaridhi, B.

    2015-05-01

    Preparation of 99mTc-ciprofloxacin for diagnosis of bacterial infection was investigated by varying factors which affected this compound. The optimum conditions for preparation of 99mTc-ciprofloxacin and a lyophilized kit for Tc-99m labelling were studied. The results from biodistribution study showed that the percentages of the injected dose per gram tissues of infected area at 1 and 3 hours after injection were around 0.25-0.56. 99mTc-ciprofloxacin was found sterile, pyrogen-free and non-toxic. Radiochemical purity was greater than 90% with greater than 6 hours of stability.

  12. Influence of thermal cycle on trapped flux in high Tc material; Koon chodendo torappu jisoku eno ondo saikuru no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Nitta, K. [Keio Univ., Tokyo (Japan); Kang, Y.M.; Fujimoto, S. [Daikin Industries Ltd., Osaka (Japan); Sawa, K.; Iwasa, Y.

    2000-05-29

    Among utilization forms of high-temperature superconductor bulks, that is paid attention is the application as a magnetic field source having a mechanism similar to a permanent magnet while generating a much greater magnetic field by trapping the magnetic field due to a pinning effect. However, when taking into consideration a degree of freedom of carrying or the like, a method called regular cooling has great restriction, thus a new cooling mechanism is desired. Therefore, an apparatus that temporally uses a refrigerating machine for cooling and uses a cold insulating device to keep the temperature below a critical temperature, thus maintaining a super-conductive state is proposed. However, despite the cold insulation, temperature rising is unavoidable, so that the superconductor is re-cooled by the refrigerating machine before it reaches the critical temperature. It has not been clarified yet how the flux trapped to a disk varies due to a thermal cycle caused by the temperature rising and repeated cooling. In this research, the variation of the trapped flux of a superconductor YBCO Disk (molten body) under a thermal cycle of 20K-40K is investigated. (NEDO)

  13. CTLA-4 (CD152) enhances the Tc17 differentiation program.

    Science.gov (United States)

    Pick, Jonas; Arra, Aditya; Lingel, Holger; Hegel, J Kolja; Huber, Magdalena; Nishanth, Gopala; Jorch, Gerhard; Fischer, Klaus-Dieter; Schlüter, Dirk; Tedford, Kerry; Brunner-Weinzierl, Monika C

    2014-07-01

    Although CD8(+) T cells that produce IL-17 (Tc17 cells) have been linked to host defense, Tc17 cells show reduced cytotoxic activity, which is the characteristic function of CD8(+) T cells. Here, we show that CTLA-4 enhances the frequency of IL-17 in CD8(+) T cells, indicating that CTLA-4 (CD152) specifically promotes Tc17 differentiation. Simultaneous stimulation of CTLA-4(+/+) and CTLA-4(-/-) T cells in cocultures and agonistic CTLA-4 stimulation unambiguously revealed a cell-intrinsic mechanism for IL-17 control by CTLA-4. The quality of CTLA-4-induced Tc17 cells was tested in vivo, utilizing infection with the facultative intracellular bacterium Listeria monocytogenes (LM). Unlike CTLA-4(+/+) Tc17 cells, CTLA-4(-/-) were nearly as efficient as Tc1 CTLA-4(+/+) cells in LM clearance. Additionally, adoptively transferred CTLA-4(-/-) Tc17 cells expressed granzyme B after rechallenge, and produced Tc1 cytokines such as IFN-γ and TNF-α, which strongly correlate with bacterial clearance. CTLA-4(+/+) Tc17 cells demonstrated a high-quality Tc17 differentiation program ex vivo, which was also evident in isolated IL-17-secreting Tc17 cells, with CTLA-4-mediated enhanced upregulation of Tc17-related molecules such as IL-17A, RORγt, and IRF-4. Our results show that CTLA-4 promotes Tc17 differentiation that results in robust Tc17 responses. Its inactivation might therefore represent a central therapeutic target to enhance clearance of infection.

  14. Reassessment of the electronic state, magnetism, and superconductivity in high-Tc cuprates with the Nd2CuO4 structure

    Science.gov (United States)

    Naito, Michio; Krockenberger, Yoshiharu; Ikeda, Ai; Yamamoto, Hideki

    2016-04-01

    The electronic phase diagram of the cuprates remains enigmatic and is still a key ingredient to understand the mechanism of high-Tc superconductivity. It has been believed for a long time that parent compounds of cuprates were universally antiferromagnetic Mott insulators (charge-transfer insulators) and that high-Tc superconductivity would develop upon doping holes or electrons in a Mott-Hubbard insulator ("doped Mott-insulator scenario"). However, our recent discovery of superconductivity in the parent compounds of square-planar cuprates with the Nd2CuO4 (T') structure and the revised electronic phase diagram in T' cuprates urged a serious reassessment to the above scenario. In this review, we present the main results derived from our synthesis and experiments on T' cuprates in the undoped or heavily underdoped regime over 20 years, including material issues and basic physics. The key material issue is how to remove excess oxygen ions at the apical site without introducing oxygen vacancies in the CuO2 planes. In order to put this into practice, the basic knowledge of complex solid-state chemistry in T' cuprates is required, which is also included in this review.

  15. 99mTc-IgG-Lung Scintigraphy in the Assessment of Pulmonary Involvement in Interstitial Lung Disease and Its Comparison With Pulmonary Function Tests and High-Resolution Computed Tomography: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Bahtouee

    2015-08-01

    Full Text Available Background The discrimination of inactive inflammatory processes from the active form of the disease is of great importance in the management of interstitial lung disease (ILD. Objectives The aim of this study was to determine the efficacy of 99mTc-IgG scan for the detection of severity of disease compared to high-resolution computed tomography (HRCT and pulmonary function test (PFT. Patients and Methods Eight known cases of ILD including four cases of Mustard gas (MG intoxication and four patients with ILD of unknown cause were included in this study. A population of six patients without lung disease was considered as the control group. The patients underwent PFT and high-resolution computed tomography, followed by 99mTc-IgG scan. They were followed up for one year. 99mTc-IgG scan assessment of IgG uptake was accomplished both qualitatively (subjectively and semiquantitatively. Results All eight ILD patients demonstrated a strong increase in 99mTc-IgG uptake in the lungs, compared to the control patients. The 99mTc-IgG scan scores were higher in the patient group (0.64[95% confidence interval(CI=0.61-0.69] than the control group (0.35 (0.35[95% CI=0.28-0.40], (P 0.05. There were no significant correlations between 99mTc-IgG score and HRCT patterns including ground glass opacity, reticular fibrosis and honeycombing (P value > 0.05. Conclusion The present results confirmed that 99mTc-IgG scan could be applied to detect the severity of pulmonary involvement, which was well correlated with HRCT findings. This data also showed that the 99mTc-IgG scan might be used as a complement to HRCT in the functional evaluation of the clinical status in ILD; however, further studies are recommended.

  16. Fabrication and properties of high-Tc films deposited on LaGaO sub 3 and LaAlO sub 3 substrates

    Energy Technology Data Exchange (ETDEWEB)

    Sobolewski, R.; Gierlowski, P.; Kula, W.; Jung, G.; Zarembinski, S.; Berkowski, M.; Dabkowski, A.; Pajaczkowska, A. (Inst. of Physics, Polish Academy of Sciences, Warszawa (Poland))

    1989-12-01

    We report on our progress in the fabrication and characterization of high-Tc thin films prepared on the in-house grown single crystal LaGaO{sub 3} and LaAlO{sub 3} substrates. Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O films were deposited using a chemical-spray technique and a dc-magnetron-sputtering process, followed by an ex-situ high temperature annealing. In the case of LaAlO{sub 3} substrates, both fabrication methods resulted in highly oriented films, characterized by very good superconducting properties. On the LaGaO{sub 3} substrates we succeeded in fabricating only Bi-Sr-Ca-Cu-O superconducting films. (orig.).

  17. Amplified Late Pliocene terrestrial warmth in northern high latitudes from greater radiative forcing and closed Arctic Ocean gateways

    Science.gov (United States)

    Feng, Ran; Otto-Bliesner, Bette L.; Fletcher, Tamara L.; Tabor, Clay R.; Ballantyne, Ashley P.; Brady, Esther C.

    2017-05-01

    . High insolation, greater CO2 forcing, and Arctic gateways closure each contributes to reduce the underestimate by enhancing the Arctic warmth of 1-2 °C. These results highlight the importance of considering proxy NHL warmth in the context of Pliocene Arctic gateway changes, and variations in insolation and CO2 forcing.

  18. A two-phase charge-density real-space-pairing model of high-Tc superconductivity.

    Science.gov (United States)

    Humphreys

    1999-03-01

    It is usually assumed that high-T(c) superconductors have a periodic band structure and a periodic charge density, although amorphous low-T(c) superconductors are known. In this paper, it is suggested that the CuO(2) conduction planes of cuprate superconductors consist of regions of two different charge densities which do not normally repeat periodically. It is suggested that the pairing of holes occurs in real space in cuprate superconductors. It is proposed that the hole-pairing mechanism is magnetic exchange coupling and the pairing force is strong, the pairing energy being greater than kT at room temperature. The bound hole pair is essentially a bipolaron. A real-space model is very tentatively suggested in which the CuO(2) planes of YBa(2)Cu(3)O(7) contain nanodomains of a 3 x 3 hole lattice surrounded by interfaces one unit cell wide in which the holes are paired. In the superconducting state in this model, the existing hole pairs condense and move coherently and collectively around the insulating nanodomains, like trams running around blocks of houses, with one hole on each tramline. The hole pairs move in an elegant manner with hole pairs hopping from oxygen to oxygen via adjacent copper sites. The model explains the superconducting current being in the ab plane and it also explains the very short coherence lengths. Because the pairing force is strong, the model suggests that room-temperature superconductivity might be possible in carefully designed new oxide materials.

  19. Tc Generator Development: Up-to-Date Tc Recovery Technologies for Increasing the Effectiveness of Mo Utilisation

    Directory of Open Access Journals (Sweden)

    Van So Le

    2014-01-01

    Full Text Available A review on the Mo sources available today and on the Tc generators developed up to date for increasing the effectiveness of Mo utilisation is performed in the format of detailed description of the features and technical performance of the technological groups of the Mo production and Tc recovery. The latest results of the endeavour in this field are also surveyed in regard of the technical solution for overcoming the shortage of Mo supply. The technological topics are grouped and discussed in a way to reflect the similarity in the technological process of each group. The following groups are included in this review which are high specific activity Mo: the current issues of production, the efforts of more effective utilisation, and the high specific activity Mo-based Tc generator and Tc concentration units; low specific activity Mo: the Mo production based on neutron capture and accelerators and the direct production of Tc and the methods of increasing the specific activity of Mo using Szilard-Chalmers reaction and high electric power isotopic separator; up-to-date technologies of Tc recovery from low specific activity Mo: the solvent extraction-based Tc generator, the sublimation methods for Mo/Tc separation, the electrochemical method for Tc recovery, and the column chromatographic methods for Tc recovery. Besides the traditional Tc-generator systems, the integrated Tc generator systems (Tc generator column combined with postelution purification/concentration unit are discussed with the format of process diagram and picture of real generator systems. These systems are the technetium selective sorbent column-based generators, the high Mo-loading capacity column-based integrated Tc generator systems which include the saline-eluted generator systems, and the nonsaline aqueous and organic solvent eluent-eluted generator systems using high Mo-loading capacity molybdategel and recently developed sorbent columns. Tc concentration methods used in the

  20. SHMUTZ & PROTON-DIAMANT H + Irradiated/Written-Hyper/Super-conductivity(HC/SC) Precognizance/Early Experiments Connections: Wet-Graphite Room-Tc & Actualized MgB2 High-Tc: Connection to Mechanical Bulk-Moduli/Hardness: Diamond Hydrocarbon-Filaments, Disorder, Nano-Powders:C,Bi,TiB2,TiC

    Science.gov (United States)

    Wunderman, Irwin; Siegel, Edward Carl-Ludwig; Lewis, Thomas; Young, Frederic; Smith, Adolph; Dresschhoff-Zeller, Gieselle

    2013-03-01

    SHMUTZ: ``wet-graphite''Scheike-....[Adv.Mtls.(7/16/12)]hyper/super-SCHMUTZ-conductor(S!!!) = ``wet''(?)-``graphite''(?) = ``graphene''(?) = water(?) = hydrogen(?) =ultra-heavy proton-bands(???) = ...(???) claimed room/high-Tc/high-Jc superconductOR ``p''-``wave''/ BAND(!!!) superconductIVITY and actualized/ instantiated MgB2 high-Tc superconductors and their BCS- superconductivity: Tc Siegel[ICMAO(77);JMMM 7,190(78)] connection to SiegelJ.Nonxline-Sol.40,453(80)] disorder/amorphous-superconductivity in nano-powders mechanical bulk/shear(?)-moduli/hardness: proton-irradiated diamond, powders TiB2, TiC,{Siegel[Semis. & Insuls.5:39,47, 62 (79)])-...``VS''/concommitance with Siegel[Phys.Stat.Sol.(a)11,45(72)]-Dempsey [Phil.Mag. 8,86,285(63)]-Overhauser-(Little!!!)-Seitz-Smith-Zeller-Dreschoff-Antonoff-Young-...proton-``irradiated''/ implanted/ thermalized-in-(optimal: BOTH heat-capacity/heat-sink & insulator/maximal dielectric-constant) diamond: ``VS'' ``hambergite-borate-mineral transformable to Overhauser optimal-high-Tc-LiBD2 in Overhauser-(NW-periodic-table)-Land: CO2/CH4-ETERNAL-sequestration by-product: WATER!!!: physics lessons from

  1. Direct 99m Tc labeling of Herceptin (trastuzumab) by 99m Tc(I) tricarbonyl ion.

    Science.gov (United States)

    Chen, Wan-Jou; Yen, Chao-Liang; Lo, Su-Tang; Chen, Kuo-Ting; Lo, Jem-Mau

    2008-03-01

    By simply incubating Herceptin (trastuzumab) with [99m Tc(CO)3(OH2)3]+ ion in saline, a significant yield of 99m Tc-labeled trastuzumab was found to be achievable. The effective labeling may be based on that trastuzumab is inherent with endogenous histidine group to which 99m Tc(I) tricarbonyl ion can be strongly bound. For practical 99m Tc labeling processing, trastuzumab was purified beforehand from the commercial product, Herceptin (Genentech) via size exclusion chromatography to remove the excipient, alpha-histidine and a high-labeled yield could be obtained by incubating the purified trastuzumab with [99m Tc(CO)3(OH2)3]+. Retention of bioactivity of the 99m Tc(I)-labeled trastuzumab was validated using a cell binding test.

  2. pTC-1 observation of ion high-speed flow reversal in the near-Earth plasma sheet during substorm

    Institute of Scientific and Technical Information of China (English)

    H.; RME; I.; DANDOURAS; C.; M.; CARR

    2008-01-01

    Based on measurements of FGM and HIA on board TC-1 at its apogee on Septem-ber 14, 2004, we analyzed the ion high-speed flows in the near-Earth plasma sheet observed during the substorm expansion phase. Strong tailward high-speed flows (Vx ~ -350 km/s) were first seen at about X ~ -13.2 RE in near-Earth magnetotail, one minute later the flows reversed from tailward to earthward. The reversal process occurred quickly after the substorm expansion onset. The near-Earth magnetotail plasma sheet was one of key regions for substorm onset. Our analysis showed that the ion flow reversal from tailward to earthward was likely to be in close relation with the substorm expansion initiation and might play an important role in trigger-ing the substorm expansion onset.

  3. High T(c) electron doped Ca10(Pt3As8)(Fe2As2)5 and Ca10(Pt4As8)(Fe2As2)5 superconductors with skutterudite intermediary layers.

    Science.gov (United States)

    Ni, Ni; Allred, Jared M; Chan, Benny C; Cava, Robert Joseph

    2011-11-01

    It has been argued that the very high transition temperatures of the highest T(c) cuprate superconductors are facilitated by enhanced CuO(2) plane coupling through heavy metal oxide intermediary layers. Whether enhanced coupling through intermediary layers can also influence T(c) in the new high T(c) iron arsenide superconductors has never been tested due the lack of appropriate systems for study. Here we report the crystal structures and properties of two iron arsenide superconductors, Ca(10)(Pt(3)As(8))(Fe(2)As(2))(5) (the "10-3-8 phase") and Ca(10)(Pt(4)As(8))(Fe(2)As(2))(5) (the "10-4-8 phase"). Based on -Ca-(Pt(n)As(8))-Ca-Fe(2)As(2)- layer stacking, these are very similar compounds for which the most important differences lie in the structural and electronic characteristics of the intermediary platinum arsenide layers. Electron doping through partial substitution of Pt for Fe in the FeAs layers leads to T(c) of 11 K in the 10-3-8 phase and 26 K in the 10-4-8 phase. The often-cited empirical rule in the arsenide superconductor literature relating T(c) to As-Fe-As bond angles does not explain the observed differences in T(c) of the two phases; rather, comparison suggests the presence of stronger FeAs interlayer coupling in the 10-4-8 phase arising from the two-channel interlayer interactions and the metallic nature of its intermediary Pt(4)As(8) layer. The interlayer coupling is thus revealed as important in enhancing T(c) in the iron pnictide superconductors.

  4. High-Tc copper oxide superconductors and related novel materials dedicated to prof K. A. Müller on the occasion of his 90th birthday

    CERN Document Server

    Keller, Hugo; Bianconi, Antonio

    2017-01-01

    Authored by many of the world's leading experts on high-Tc superconductivity, this volume presents a panorama of ongoing research in the field, as well as insights into related multifunctional materials. The contributions cover many different and complementary aspects of the physics and materials challenges, with an emphasis on superconducting materials that have emerged since the discovery of the cuprate superconductors, for example pnictides, MgB2, H2S and other hydrides. Special attention is also paid to interface superconductivity. In addition to superconductors, the volume also addresses materials related to polar and multifunctional ground states, another class of materials that owes its discovery to Prof. Müller's ground-breaking research on SrTiO3.

  5. Effects of pairing potential scattering on Fourier-transformed inelastic tunneling spectra of high-Tc cuprate superconductors with bosonic modes.

    Science.gov (United States)

    Zhu, Jian-Xin; McElroy, K; Lee, J; Devereaux, T P; Si, Qimiao; Davis, J C; Balatsky, A V

    2006-10-27

    Recent scanning tunneling microscopy (STM) experimentally observed strong gap inhomogeneity in Bi2Sr2CaCu2O(8+delta) (BSCCO). We argue that disorder in the pair potential underlies the gap inhomogeneity, and investigate its role in the Fourier-transformed inelastic tunneling spectra as revealed in the STM. We find that the random pair potential induces unique q-space patterns in the local density of states (LDOS) of a d-wave superconductor. We consider the effects of electron coupling to various bosonic modes and find the pattern of LDOS modulation due to coupling to the B(1g) phonon mode to be consistent with the one observed in the inelastic electron tunnneling STM experiment in BSCCO. These results suggest strong electron-lattice coupling as an essential part of the superconducting state in high-Tc materials.

  6. Fracture behavior of an inclined crack interacting with a circular inclusion in a high-TC superconductor under an electromagnetic force

    Directory of Open Access Journals (Sweden)

    Feng Xue

    2015-11-01

    Full Text Available A simple model is proposed to investigate the interaction problem for a circular nonsuperconducting inclusion embedded in a high-TC superconducting matrix which contains an inclined crack, oriented at an arbitrary angle from the direction of the critical currents. The electromagnetic behavior is described by the critical state, the original Bean model. The perturbation brought upon by the circular inclusion and the crack on the critical current density is assumed to be negligible and not considered in this model. The distribution dislocation technology is applied to formulate the current problem. The stress intensity factors (SIFs are obtained by solving the formulated singular integral equations. The effects of the crack angle, the elastic modulus, the inclusion-crack distance and the inclusion-crack size on the stress intensity factors are discussed in detail.

  7. Fracture behavior of an inclined crack interacting with a circular inclusion in a high-TC superconductor under an electromagnetic force

    Science.gov (United States)

    Xue, Feng; Zhang, Zhaoxia; Gou, Xiaofan

    2015-11-01

    A simple model is proposed to investigate the interaction problem for a circular nonsuperconducting inclusion embedded in a high-TC superconducting matrix which contains an inclined crack, oriented at an arbitrary angle from the direction of the critical currents. The electromagnetic behavior is described by the critical state, the original Bean model. The perturbation brought upon by the circular inclusion and the crack on the critical current density is assumed to be negligible and not considered in this model. The distribution dislocation technology is applied to formulate the current problem. The stress intensity factors (SIFs) are obtained by solving the formulated singular integral equations. The effects of the crack angle, the elastic modulus, the inclusion-crack distance and the inclusion-crack size on the stress intensity factors are discussed in detail.

  8. Ice hydrometeor profile retrieval algorithm for high frequency microwave radiometers: application to the CoSSIR instrument during TC4

    Directory of Open Access Journals (Sweden)

    K. F. Evans

    2012-04-01

    Full Text Available A Bayesian algorithm to retrieve profiles of cloud ice water content (IWC, ice particle size (Dme, and relative humidity from millimeter-wave/submillimeter-wave radiometers is presented. The first part of the algorithm prepares an a priori file with cumulative distribution functions (CDFs and empirical orthogonal functions (EOFs of profiles of temperature, relative humidity, three ice particle parameters (IWC, Dme, distribution width, and two liquid cloud parameters. The a priori CDFs and EOFs are derived from CloudSat radar reflectivity profiles and associated ECMWF temperature and relative humidity profiles combined with three cloud microphysical probability distributions obtained from in situ cloud probes. The second part of the algorithm uses the CDF/EOF file to perform a Bayesian retrieval with a hybrid technique that uses Monte Carlo integration (MCI or, when too few MCI cases match the observations, uses optimization to maximize the posterior probability function. The very computationally intensive Markov chain Monte Carlo (MCMC method also may be chosen as a solution method. The radiative transfer model assumes mixtures of several shapes of randomly oriented ice particles, and here random aggregates of hexagonal plates, spheres, and dendrites are used for tropical convection. A new physical model of stochastic dendritic snowflake aggregation is developed. The retrieval algorithm is applied to data from the Compact Scanning Submillimeter-wave Imaging Radiometer (CoSSIR flown on the ER-2 aircraft during the Tropical Composition, Cloud and Climate Coupling (TC4 experiment in 2007. Example retrievals with error bars are shown for nadir profiles of IWC, Dme, and relative humidity, and nadir and conical scan swath retrievals of ice water path and average Dme. The ice cloud retrievals are evaluated by retrieving integrated 94 GHz backscattering from CoSSIR for comparison

  9. Ice hydrometeor profile retrieval algorithm for high frequency microwave radiometers: application to the CoSSIR instrument during TC4

    Science.gov (United States)

    Evans, K. F.; Wang, J. R.; O'C Starr, D.; Heymsfield, G.; Li, L.; Tian, L.; Lawson, R. P.; Heymsfield, A. J.; Bansemer, A.

    2012-04-01

    A Bayesian algorithm to retrieve profiles of cloud ice water content (IWC), ice particle size (Dme), and relative humidity from millimeter-wave/submillimeter-wave radiometers is presented. The first part of the algorithm prepares an a priori file with cumulative distribution functions (CDFs) and empirical orthogonal functions (EOFs) of profiles of temperature, relative humidity, three ice particle parameters (IWC, Dme, distribution width), and two liquid cloud parameters. The a priori CDFs and EOFs are derived from CloudSat radar reflectivity profiles and associated ECMWF temperature and relative humidity profiles combined with three cloud microphysical probability distributions obtained from in situ cloud probes. The second part of the algorithm uses the CDF/EOF file to perform a Bayesian retrieval with a hybrid technique that uses Monte Carlo integration (MCI) or, when too few MCI cases match the observations, uses optimization to maximize the posterior probability function. The very computationally intensive Markov chain Monte Carlo (MCMC) method also may be chosen as a solution method. The radiative transfer model assumes mixtures of several shapes of randomly oriented ice particles, and here random aggregates of hexagonal plates, spheres, and dendrites are used for tropical convection. A new physical model of stochastic dendritic snowflake aggregation is developed. The retrieval algorithm is applied to data from the Compact Scanning Submillimeter-wave Imaging Radiometer (CoSSIR) flown on the ER-2 aircraft during the Tropical Composition, Cloud and Climate Coupling (TC4) experiment in 2007. Example retrievals with error bars are shown for nadir profiles of IWC, Dme, and relative humidity, and nadir and conical scan swath retrievals of ice water path and average Dme. The ice cloud retrievals are evaluated by retrieving integrated 94 GHz backscattering from CoSSIR for comparison with the Cloud Radar System (CRS) flown on the same aircraft. The rms difference in

  10. Determination of Tc-99 in radioactive wastes; Determinacion de Tc-99 en desechos radiactivos

    Energy Technology Data Exchange (ETDEWEB)

    Rivera S, A. A.

    2015-07-01

    Tc-99 is a fission product and one of the most important radionuclides from the view point of safety assessment for the disposal of radioactive waste because of its long half-life (2.1 x 10{sup 5} years) and high mobility in soil-water systems, if this is released into the environment in significant quantities can concentrate on plants and animals. Tc-99 is a pure beta emitter with a maximum energy of 292 KeV, so their quantification imposes destructive methods to be analyzed by liquid scintillation. Therefore the quantification of Tc-99 in ion exchange resins requires of the mineralization of these and separation of Tc-99 of other radioisotopes present in the resin. Therefore the object of this thesis is to develop a quantification method of Tc-99 content in spent exchange resins. So in order to track the behavior of technetium during digestion exchange resins and radiochemical separation, given its high volatility, in this work the {sup 99m}Tc is used. To determine the degree of mineralization of the resins, an analysis was performed by chromatography. Subsequently the method used to determine the percentage of {sup 99m}Tc aerosolized during mineralization of resin is described. After the method for the radiochemical separation of {sup 99m}Tc is presented by liquid-liquid extraction using crown ether as extractant; for this testing was performed by varying the molarity of the extractant, the ratio of solvent extractant, type of digestion of the resin and the presence of Sr-85, in order to study the behavior of {sup 99m}Tc in the presence of this radioisotope. Finally, a track beta spectra of a sample of {sup 99m}Tc eluted from a generator {sup 99}Mo/{sup 99m}Tc function of time was performed. (Author)

  11. Possible association of ABCB1:c.3435T>C polymorphism with high-density-lipoprotein-cholesterol response to statin treatment - a pilot study.

    Directory of Open Access Journals (Sweden)

    Anna Sałacka

    2014-08-01

    Full Text Available The gene product ABCB1 (formerly MDR1 or P-glycoprotein is hypothesized to be involved in cholesterol cellular trafficking, redistribution and intestinal re-absorption. Carriers of the ABCB1:3435T allele have previously been associated with decreases in ABCB1 mRNA and protein concentrations and have been correlated with changes in serum lipid concentrations. The aim of this study was to investigate possible association between the ABCB1:3435T>C polymorphism and changes in lipids in patients following statin treatment. Outpatients (n=130 were examined: 43 men (33%, 87 women (67%: treated with atorvastatin or simvastatin (all patients with equivalent dose of 20 or 40 mg/d simvastatin. Blood was taken for ABCB1:3435T>C genotyping, and before and after statin treatment for lipid concentration determination (total cholesterol, high-density-lipoprotein-cholesterol (HDL-C, triglycerides. Change (Δ in lipid parameters, calculated as differences between measurements before and after treatment, were analyzed with multiple regression adjustments: gender, diabetes, age, body mass index, equivalent statin dose, length of treatment. Univariate and multivariate analyses showed significant differences in ΔHDL-C (univariate p=0.029; multivariate p=0.036 and %ΔHDL-C (univariate p=0.021; multivariate p=0.023 between patients with TT (-0.05 ± 0.13 g/l; -6.8% ± 20%; respectively and CC+CT genotypes (0.004 ± 0.15 g/l; 4.1 ± 26%; respectively. Reduction of HDL-C in homozygous ABCB1:3435TT patients suggests this genotype could be associated with a reduction in the benefits of statin treatment.

  12. Tc Chemistry in HLW: Role of Organic Complexants

    Energy Technology Data Exchange (ETDEWEB)

    Hess, Nancy S.; Conradsen, Steven D.

    2003-06-01

    Tc complexation with organic compounds in tank waste plays a significant role in the redox chemistry of Tc and the partitioning of Tc between the supernatant and sludge components in waste tanks. These processes need to be understood so that strategies to effectively remove Tc from high-level nuclear waste prior to waste immobilization can be developed and so that long-term consequences of Tc remaining in residual waste after sludge removal can be evaluated. Only limited data on the stability of Tc-organic complexes exists and even less thermodynamic data on which to develop predictive models of Tc chemical behavior is available. To meet these challenges we are conducting a research program to study to develop thermodynamic data on Tc-organic complexation over a wide range of chemical conditions. We will attempt to characterize Tc-speciation in actual tank waste using state-of-the-art analytical organic chemistry, separations, and speciation techniques to validate our model. On the basis of such studies we will develop credible model of Tc chemistry in HLW that will allow prediction of Tc speciation in tank waste and Tc behavior during waste pretreatment processing and in waste tank residuals.

  13. Analysis and Simulation of CNC High Speed Turning TC4 Cutting Force%数控高速车削TC4切削力分析与模拟

    Institute of Scientific and Technical Information of China (English)

    许光彬; 韩江

    2015-01-01

    通过理论分析高速干切削TC4切削用量对切削力的影响规律,并利用Deform-3D仿真分析了切削用量对切削力的影响,得出切削力与切削速度近似符合Salomon假说中关于切削力的变化规律;切削力与切削深度、进给量近似成正比.结果证明:理论分析与仿真结果与实际情况较为吻合,对于揭示了高速切削TC4变形机理,改善其表面质量和提高刀具使用寿命和建立高速切削参数数据库具有指导意义.

  14. 99mTc-MIBI Lung Scintigraphy in the Assessment of Pulmonary Involvement in Interstitial Lung Disease and Its Comparison With Pulmonary Function Tests and High-Resolution Computed Tomography

    Science.gov (United States)

    Bahtouee, Mehrzad; Saberifard, Jamshid; Javadi, Hamid; Nabipour, Iraj; Raeisi, Alireza; Assadi, Majid; Eftekhari, Mohammad

    2015-01-01

    Abstract The differentiation of active inflammatory processes from an inactive form of the disease is of great value in the management of interstitial lung disease (ILD). The aim of this investigation was to assess the efficacy of 99mTc-methoxy-isobutyl-isonitrile (99mTc-MIBI) scans in distinguishing the severity of the disease compared to radiological and clinical parameters. In total, 19 known cases of ILD were included in this study and were followed up for 1 year. Five patients without lung disease were considered as the control group. The patients underwent pulmonary function tests (PFTs) and high-resolution computed tomography scans, followed by 99mTc-MIBI scanning. The 99mTc-MIBI scans were analyzed either qualitatively (subjectively) or semiquantitatively. All 19 ILD patients demonstrated a strong increase in 99mTc-MIBI uptake in the lungs compared to the control group. The 99mTc-MIBI scan scores were higher in the patient group in both the early phase (0.24[0.19–0.31] vs 0.11[0.10–0.15], P  0.14). The 99mTc-MIBI scan scores were not significantly correlated with the PFT findings (P > 0.05). In total, 5 patients died and 14 patients were still alive over the 1-year follow-up period. There was also a significant difference between the uptake intensity of 99mTc-MIBI and the outcome in the early phase (dead: 0.32[0.29–0.43] vs alive: 0.21[0.18–0.24], P lung scans might distinguish the severity of pulmonary involvement in early views, which were well correlated with HRCT findings. These results also revealed that 99mTc-MIBI lung scans might be used as a complement to other diagnostic and clinical examinations in terms of functional information in ILD; however, further investigations are strongly required. PMID:26632717

  15. New multi-purpose high copy number vector with greater mitotic stability for diverse applications in fission yeast Schizosaccharomyces pombe.

    Science.gov (United States)

    Verma, Hemant Kumar; Singh, Jagmohan

    2012-11-01

    We have constructed a pUC19-based multipurpose ATG vector in Schizosaccharomyces pombe with higher copy number and mitotic stability possible with commonly used vectors. The vector, having an NdeI site in its polylinker to provide ATG site for expression, carries a greatly truncated version of URA3 gene, URA3m, of Saccharomyces cerevisiae as a selection marker. In addition, it contains the mat2P-right flank region (mat2P-RF) of S. pombe as an autonomous replicating sequence (ARS) and a polylinker with wider choice of restriction sites. While URA3m confers an increase in plasmid copy number up to 200 copies/cell, mat2P-RF imparts greater mitotic stability than the standard ars1 element of S. pombe. Finally, the vector also includes the transcription termination signal of the nmt1 gene (Tnmt1). This basic vector should serve as a versatile tool for studies of gene function in S. pombe.

  16. Effect of double glow plasma surface chromizing on high-temperature oxidation resistance of TC4 titanium alloy%TC4合金双辉等离子渗Cr高温氧化行为

    Institute of Scientific and Technical Information of China (English)

    魏东博; 张平则; 姚正军; 梁文萍; 缪强; 徐重

    2011-01-01

    Isothermal oxidation behavior of TC4 titanium alloy,which was chromized by the double glow plasma surface alloying technology(DGP),were investigated at 650 ℃,750 ℃ and 850 ℃.The results show that the chromizing layer consists of surface loose layer,compact deposited layer and Ti-Cr mutual diffusion layer.The diffusion layer has better oxidation resistance compared with NiCrAlY thermal barrier coating.The ratio of Cr to Ti content in the diffusion layer exhibits gradient distribution by Cr,Cr1.97Ti1.07 and CrTi4.Under oxidation circumstance,Cr,Ti and Al diffuse outward to form multilayer oxide films,which prevent inward diffusion of oxygen.At 650 ℃,the oxidation films consist of two layers: the external Cr2O3 layer and the internal TiO2 layer.At 750 ℃,a mixed oxide layer containing Cr2O3 and TiO2 is formed beneath the Cr2O3 layer and TiO2 layer,whereby Ti(Cr,Al)2 Laves phase is observed in the Ti-depleted layer.At 850 ℃,a mixed oxide layer containing TiO2,Ti2O3 and Ti3O5 is formed beneath the Cr2O3 layer and Al2O3 layer,whereby Ti(Cr,Al)2 Laves phase and Kirkendall voids are formed in the depletion layer.%研究了双层辉光等离子渗Cr对TC4合金650、750、850℃恒温氧化性能的影响。结果表明:渗Cr后,表面梯度合金层显著提高了TC4合金的高温氧化性能,Ti-Cr互扩散层可有效阻止氧向基体扩散。氧化过程中,Ti、Cr向外扩散形成TiO2/Cr2O3氧化膜,其形态与氧化温度有关。850℃氧化100 h后,渗Cr试样表面形成致密Cr2O3膜,恒温氧化性能优于NiCrAlY热障涂层。

  17. Bright upconversion luminescence and increased Tc in CaBi{sub 2}Ta{sub 2}O{sub 9}:Er high temperature piezoelectric ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Peng Dengfeng [Functional Materials Research Laboratory, Tongji University, 1239 Siping Road, Shanghai 200092 (China); National Institute of Advanced Industrial Science and Technology, Kyushu, 807-1 Shuku, Tosu, Saga 841-0052 (Japan); Wang Xusheng; Yao Xi [Functional Materials Research Laboratory, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Xu Chaonan [National Institute of Advanced Industrial Science and Technology, Kyushu, 807-1 Shuku, Tosu, Saga 841-0052 (Japan); Lin Jian; Sun Tiantuo [College of Material Science and Engineering, Tongji University, 4800 Cao' an Highway, Shanghai 201804 (China)

    2012-05-15

    Er{sup 3+} doped CaBi{sub 2}Ta{sub 2}O{sub 9} (CBT) bismuth layered-structure high temperature piezoelectric ceramics were synthesized by the traditional solid state method. The upconversion (UC) emission properties of Er{sup 3+} doped CBT ceramics were investigated as a function of Er{sup 3+} concentration and incident pump power. A bright green upconverted emission was obtained under excitation 980 nm at room temperature. The observed strong green and weak red emission bands corresponded to the transitions from {sup 4}S{sub 3/2} and {sup 4}F{sub 9/2} to {sup 4}I{sub 15/2}, respectively. The dependence of UC emission intensity on pumping power indicated that a three-photon process was involved in UC emissions. Studies of dielectric with temperature have also been carried out. Introduction of Er increased the Curie temperature of CBT, thus, making this ceramic suitable for sensor applications at higher temperatures. Because of its strong up-converted emission and increased Tc, the multifunctional high temperature piezoelectric ceramic may be useful in high temperature sensor, fluorescence thermometry, and optical-electro integration applications.

  18. Development of cooling systems for high-Tc superconducting sampler; Koon chodendo sanpura reikyaku shisutemu no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, S. [Daikin Industries Ltd., Osaka (Japan). Air-Conditioning R and D Lab.; Kang, Y.M. [Daikin Industries Ltd., Osaka (Japan). ENvironmental Lab.

    2000-05-29

    The sampler applying the high speed responsibility of high temperature super-conducting Josephson junction and height of the critical current sensitivity is expected as means of accurately observing super speed digital signal waveform. The high temperature super-conducting element practically used in combination with a small sized refrigerator up to now is a microwave filter being a driven element and a SQUID being a low speed analog element. In this study, the element using high speed switching characteristic of the Josephson junction like sampler circuit is applied to two small refrigerating machines of Stirling refrigerating machine and GM type pulse tube refrigerating machine. As an example of the former, a system for observing super-speed digital waveform is introduced. In this system, Stirling refrigerating machine of 5W(at mark)80K class is used in order to obtain the cooling temperature below 40K for improving the performance of the high temperature superconductivity sampler. As an example of the latter, a current waveform measurement system is introduced. (NEDO)

  19. Establishment of an experimental human lung adenocarcinoma cell line SPC-A-1BM with high bone metastases potency by {sup 99m}Tc-MDP bone scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Yang Shunfang [Department of Nuclear Medicine, Shanghai Chest Hospital of Shanghai Jiaotong University, Shanghai 200030 (China)], E-mail: yzyg@sh163.net; Dong Qianggang [Laboratory of Mol-diagnosis, Shanghai Cancer Institute of Shanghai Jiaotong University, Shanghai 200032 (China); Yao Ming [Laboratory of Pathology, Shanghai Cancer Institute of Shanghai Jiaotong University, Shanghai 200032 (China); Shi Meiping [Department of Pathology, Shanghai Chest Hospital of Shanghai Jiaotong University, Shanghai 200030 (China); Ye Jianding [Department of Radiology, Shanghai Chest Hospital of Shanghai Jiaotong University, Shanghai 200030 (China); Zhao Langxiang [Department of Pathology, Shanghai Chest Hospital of Shanghai Jiaotong University, Shanghai 200030 (China); Su Jianzhong; Gu Weiyong [Shanghai Thoracic Tumor Institute, Shanghai Chest Hospital of Shanghai Jiaotong University, Shanghai 200030 (China); Xie Wenhui [Department of Nuclear Medicine, Shanghai Chest Hospital of Shanghai Jiaotong University, Shanghai 200030 (China); Wang Kankan; Du Yanzhi [State Key Laboratory of Medical Genomics, Ruijin Hospital of Shanghai Jiaotong University, Shanghai 200025 (China); Li Yao [State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai 200433 (China); Huang Yan [State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai 200433 (China)], E-mail: huangyan@fudan.edu.cn

    2009-04-15

    Background: Bone metastasis is one of the most common clinical phenomena of late stage lung cancer. A major impediment to understanding the pathogenesis of bone metastasis has been the lack of an appropriate animal and cell model. This study aims to establish human lung adenocarcinoma cell line with highly bone metastases potency with {sup 99m}Tc-MDP bone scintigraphy. Methods: The human lung adenocarcinoma cancer cells SPC-A-1 were injected into the left cardiac ventricle of NIH-Beige-Nude-XID (NIH-BNX) immunodeficient mice. The metastatic lesions of tumor-bearing mice were imaged with {sup 99m}Tc-MDP bone scintigraphy on a Siemens multi-single photon emission computed tomography. Pinhole images were acquired on a GZ-B conventional gamma camera with a self-designed pinhole collimator. The mice with bone metastasis were sacrificed under deep anesthesia, and the lesions were resected. Bone metastatic cancer cells in the resected lesions were subjected for culture and then reinoculated into the NIH-BNX mice through left cardiac ventricle. The process was repeated for eight cycles to obtain a novel cell subline SPC-A-1BM. Real-time polymerase chain reaction (PCR) was used to compare the gene expression differences in the parental and SPC-A-1BM cells. Results: The bone metastasis sites were successfully revealed by bone scintigraphy. The established bone metastasis cell line SPC-A-1BM had a high potential to metastasize in bone, including mandible, humerus, thoracic vertebra, lumbar, femur, patella, ilium and cartilage rib. The expression level of vascular endothelial growth factor gene family, Bcl-2 and cell adhesion-related genes ECM1, ESM1, AF1Q, SERPINE2 and FN1 were examined. Gene expression difference was found between parental and bone-seeking metastasis cell SPC-A-1BM, which indicates SPC-A-1BM has metastatic capacity vs. its parental cells. Conclusion: SPC-A-1BM is a bone-seeking metastasis human lung adenocarcinoma cell line. Bone scintigraphy may be used as

  20. Establishment of an experimental human lung adenocarcinoma cell line SPC-A-1BM with high bone metastases potency by (99m)Tc-MDP bone scintigraphy.

    Science.gov (United States)

    Yang, Shunfang; Dong, Qianggang; Yao, Ming; Shi, Meiping; Ye, Jianding; Zhao, Langxiang; Su, Jianzhong; Gu, Weiyong; Xie, Wenhui; Wang, Kankan; Du, Yanzhi; Li, Yao; Huang, Yan

    2009-04-01

    Bone metastasis is one of the most common clinical phenomena of late stage lung cancer. A major impediment to understanding the pathogenesis of bone metastasis has been the lack of an appropriate animal and cell model. This study aims to establish human lung adenocarcinoma cell line with highly bone metastases potency with (99m)Tc-MDP bone scintigraphy. The human lung adenocarcinoma cancer cells SPC-A-1 were injected into the left cardiac ventricle of NIH-Beige-Nude-XID (NIH-BNX) immunodeficient mice. The metastatic lesions of tumor-bearing mice were imaged with (99m)Tc-MDP bone scintigraphy on a Siemens multi-single photon emission computed tomography. Pinhole images were acquired on a GZ-B conventional gamma camera with a self-designed pinhole collimator. The mice with bone metastasis were sacrificed under deep anesthesia, and the lesions were resected. Bone metastatic cancer cells in the resected lesions were subjected for culture and then reinoculated into the NIH-BNX mice through left cardiac ventricle. The process was repeated for eight cycles to obtain a novel cell subline SPC-A-1BM. Real-time polymerase chain reaction (PCR) was used to compare the gene expression differences in the parental and SPC-A-1BM cells. The bone metastasis sites were successfully revealed by bone scintigraphy. The established bone metastasis cell line SPC-A-1BM had a high potential to metastasize in bone, including mandible, humerus, thoracic vertebra, lumbar, femur, patella, ilium and cartilage rib. The expression level of vascular endothelial growth factor gene family, Bcl-2 and cell adhesion-related genes ECM1, ESM1, AF1Q, SERPINE2 and FN1 were examined. Gene expression difference was found between parental and bone-seeking metastasis cell SPC-A-1BM, which indicates SPC-A-1BM has metastatic capacity vs. its parental cells. SPC-A-1BM is a bone-seeking metastasis human lung adenocarcinoma cell line. Bone scintigraphy may be used as an accurate, sensitive, noninvasive tool to detect

  1. Macrophages from chickens selected for high antibody response produced more nitric oxide and have greater phagocytic capacity.

    Science.gov (United States)

    Guimarães, Marco Cesar Cunegundes; Guillermo, Landi Veivi Costilla; Matta, Marcos Fernando de Rezende; Soares, Sandro Gomes; DaMatta, Renato Augusto

    2011-04-15

    Macrophages are fundamental cells of the innate immune system, which, through phagocytosis and nitric oxide production, eliminate pathogens. The aim of the present study was to determine if macrophages from chicken families divergently selected to high and low antibodies response differ in nitric oxide production and phagocytic capacity. Blood monocytes derived macrophages were activated with lipopolysaccharide and supernatant from chicken spleen lymphocytes cultured with Concanavalin A (containing chicken interferon). Nitric oxide production was evaluated in culture supernatants. Phagocytic capacity of activated and non-activated macrophages was assayed using yeasts and IgY opsonized sheep red blood cells. Activated and non-activated macrophages from the high antibodies response family produced higher nitric oxide levels, internalized more yeast and significantly more opsonized sheep red blood cells than macrophages from the low antibodies response family. Moreover, activated macrophages became more elongated and widely spread. These findings indicate that macrophages from the high antibodies response family were more active suggesting that the differences in antibody response also depend on macrophage function.

  2. High-Tc superconductivity in ultrathin Bi2Sr2CaCu2O(8+x) down to half-unit-cell thickness by protection with graphene.

    Science.gov (United States)

    Jiang, Da; Hu, Tao; You, Lixing; Li, Qiao; Li, Ang; Wang, Haomin; Mu, Gang; Chen, Zhiying; Zhang, Haoran; Yu, Guanghui; Zhu, Jie; Sun, Qiujuan; Lin, Chengtian; Xiao, Hong; Xie, Xiaoming; Jiang, Mianheng

    2014-12-08

    High-Tc superconductors confined to two dimension exhibit novel physical phenomena, such as superconductor-insulator transition. In the Bi2Sr2CaCu2O(8+x) (Bi2212) model system, despite extensive studies, the intrinsic superconducting properties at the thinness limit have been difficult to determine. Here, we report a method to fabricate high quality single-crystal Bi2212 films down to half-unit-cell thickness in the form of graphene/Bi2212 van der Waals heterostructure, in which sharp superconducting transitions are observed. The heterostructure also exhibits a nonlinear current-voltage characteristic due to the Dirac nature of the graphene band structure. More interestingly, although the critical temperature remains essentially the same with reduced thickness of Bi2212, the slope of the normal state T-linear resistivity varies by a factor of 4-5, and the sheet resistance increases by three orders of magnitude, indicating a surprising decoupling of the normal state resistance and superconductivity. The developed technique is versatile, applicable to investigate other two-dimensional (2D) superconducting materials.

  3. A comparison of rat SPECT images obtained using 99mTc derived from 99Mo produced by an electron accelerator with that from a reactor

    Science.gov (United States)

    Galea, R.; Wells, R. G.; Ross, C. K.; Lockwood, J.; Moore, K.; Harvey, J. T.; Isensee, G. H.

    2013-05-01

    Recent shortages of molybdenum-99 (99Mo) have led to an examination of alternate production methods that could contribute to a more robust supply. An electron accelerator and the photoneutron reaction were used to produce 99Mo from which technetium-99m (99mTc) is extracted. SPECT images of rat anatomy obtained using the accelerator-produced 99mTc with those obtained using 99mTc from a commercial generator were compared. Disks of 100Mo were irradiated with x-rays produced by a 35 MeV electron beam to generate about 1110 MBq (30 mCi) of 99Mo per disk. After target dissolution, a NorthStar ARSII unit was used to separate the 99mTc, which was subsequently used to tag pharmaceuticals suitable for cardiac and bone imaging. SPECT images were acquired for three rats and compared to images for the same three rats obtained using 99mTc from a standard reactor 99Mo generator. The efficiency of 99Mo-99mTc separation was typically greater than 90%. This study demonstrated the delivery of 99mTc from the end of beam to the end user of approximately 30 h. Images obtained using the heart and bone scanning agents using reactor and linac-produced 99mTc were comparable. High-power electron accelerators are an attractive option for producing 99Mo on a national scale.

  4. A comparison of rat SPECT images obtained using (99m)Tc derived from 99Mo produced by an electron accelerator with that from a reactor.

    Science.gov (United States)

    Galea, R; Wells, R G; Ross, C K; Lockwood, J; Moore, K; Harvey, J T; Isensee, G H

    2013-05-07

    Recent shortages of molybdenum-99 ((99)Mo) have led to an examination of alternate production methods that could contribute to a more robust supply. An electron accelerator and the photoneutron reaction were used to produce (99)Mo from which technetium-99m ((99m)Tc) is extracted. SPECT images of rat anatomy obtained using the accelerator-produced (99m)Tc with those obtained using (99m)Tc from a commercial generator were compared. Disks of (100)Mo were irradiated with x-rays produced by a 35 MeV electron beam to generate about 1110 MBq (30 mCi) of (99)Mo per disk. After target dissolution, a NorthStar ARSII unit was used to separate the (99m)Tc, which was subsequently used to tag pharmaceuticals suitable for cardiac and bone imaging. SPECT images were acquired for three rats and compared to images for the same three rats obtained using (99m)Tc from a standard reactor (99)Mo generator. The efficiency of (99)Mo-(99m)Tc separation was typically greater than 90%. This study demonstrated the delivery of (99m)Tc from the end of beam to the end user of approximately 30 h. Images obtained using the heart and bone scanning agents using reactor and linac-produced (99m)Tc were comparable. High-power electron accelerators are an attractive option for producing (99)Mo on a national scale.

  5. Effects of magnetic field on the cuprate high-Tc superconductor La2-xSrxCuO4

    DEFF Research Database (Denmark)

    Lake, B.; Aeppli, G.; Christensen, N.B.

    2004-01-01

    This article discusses neutron scattering measurements on the cuprate, high transition temperature superconductor La2-xSrxCuO4 (LSCO) in an applied magnetic field. LSCO is a type-II superconductor and magnetic flux can penetrate the material via the formation of vorticies. Phase coherent...

  6. TC-2 Satellite Delivered

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    On April 18, 2005, TC-2, the second satellite of Double Star Program (DSP), which was jointly developed by CNSA and ESA, was approved to be delivered to the user after the on-board test and trial operation. The satellite is working well and the performance can meet the user's need. The satellite has collected large amount of valuable scientific data

  7. Non-destructive testing (NDT) of metal cracks using a high Tc rf-SQUID and eddy current method

    Energy Technology Data Exchange (ETDEWEB)

    Lu, D.F.; Fan, C.; Ruan, J.Z. [Midwest Superconductivity Inc., Lawrence, KS (United States)] [and others

    1994-12-31

    A SQUID is the most sensitive device to detect change in magnetic field. A non-destructive testing (NDT) device using high temperature SQUIDs and eddy current method will be much more sensitive than those currently used eddy current systems, yet much cheaper than one with low temperature SQUIDs. In this paper, we present our study of such a NDT device using a high temperature superconducting rf-SQUID as a gradiometer sensor. The result clearly demonstrates the expected sensitivity of the system, and indicates the feasibility of building a portable HTS SQUID NDT device with the help from cryocooler industry. Such a NDT device will have a significant impact on metal corrosion or crack detection technology.

  8. Out-of-plane Ionicity versus In-plane Covalency Interplay in High-Tc Superconducting Oxides

    OpenAIRE

    2015-01-01

    It seems that the remarkable properties of the high temperature superconducting oxides, especially the Insulator-Metal Transition (IMT) and the Metal-Superconductor Transition (MST) both originate from the competition (interplay) between ionic versus in-plane covalence nature of bonds in these materials. As a result of this competition, the microscopic order parameter, that is firmly identified to be the local field estimated from the ionic polarization at the sub-unit level (one half of the ...

  9. Imaging of brain tumors and other lesions utilizing /sup 99m/Tc phosphates and /sup 99m/Tc pertechnetate

    Energy Technology Data Exchange (ETDEWEB)

    Schauwecker, D.S.; Burt, R.W.; Richmond, B.D.

    1982-11-01

    The intensity of parenchymal brain lesions was compared using /sup 99m/Tc pertechnetate and /sup 99m/Tc phosphate. The following conclusions were made: 1. If the /sup 99m/Tc phosphate intensity is greater than the intensity of the /sup 99m/Tc pertechnetate scan, and the patient is evaluated within four weeks of ictus, the lesion is a CVA (P less than .001). 2. If the /sup 99m/Tc phosphate intensity is less than or equal to the intensity of the /sup 99m/Tc pertechnetate scan, and the patient is evaluated within four weeks of ictus, the parenchymal lesion is not a CVA (P less than .001). 3. If the evaluation takes place longer than six weeks after ictus, then no evaluation about the nature of the lesion can be made based upon uptake of /sup 99m/Tc phosphate and /sup 99m/Tc pertechnetate.

  10. Lorentz microscopy observation of vortices in high-Tc superconductors using a 1-MV field emission transmission electron microscope.

    Science.gov (United States)

    Harada, Ken

    2013-06-01

    Lorentz microscopy has opened the door to observing a single quantized magnetic flux line (i.e. a vortex) and its dynamic behavior inside a superconductor in real time. It resulted from the efforts of Dr Akira Tonomura and his collaborators, who developed a field emission electron microscope and advanced the technologies used for visualizing vortices (e.g. a low-temperature specimen stage and a magnetic-field application system). They used a 1-MV field emission transmission electron microscope with an electron beam that can penetrate thick specimens of high-temperature superconductors (Bi2Sr2CaCu2O8+δ and YB2C3O7-δ) to reveal the flux-line features inside materials and their interactions with defects. This memorial paper reviews the results of research in the area of vortex matter physics.

  11. Study on Recovery Performance of High Tc Superconducting Tapes for Resistive Type Superconducting Fault Current Limiter Applications

    Science.gov (United States)

    kar, Soumen; Kulkarni, Sandeep; Dixit, Manglesh; Singh, Kuwar Pal; Gupta, Alok; Balasubramanyam, P. V.; Sarangi, S. K.; Rao, V. V.

    Recent advances in reliable production of long length high temperature superconducting (HTS) tapes have resulted in commercial application of superconducting fault current limiters (SFCLs) in electrical utility networks. SFCL gives excellent technical performance when compared to conventional fault current limiters. The fast self-recovery from normal state to superconducting state immediately after the fault removal is an essential criterion for resistive type SFCL operation. In this paper, results on AC over-current testing of 1st generation (1G) Bi2223 tapes and 2nd generation (2G) YBCO coated conductors operating at 77 K are reported. From these results, the recovery time is estimated for different available HTS tapes in the market. The current limiting tests have also been performed to study the effective current limitation. Further, the recovery characteristics after the current limitation are quantitatively discussed for repetitive faults for different time intervals in the range of 100 ms to few seconds.

  12. Crystal Growth and Electronic Raman Scattering Study of Model High-Tc Cuprate HgBa2 CaCu2 O6 +Ä

    Science.gov (United States)

    Wang, Lichen; Li, Yuan; Luo, Xiangpeng; Li, Jiarui; Yuan Li's Group in ICQM Team

    In this talk, I will report our recent progress on crystal growth of HgBa2CaCu2O6 +x (Hg1212), which possesses a simple tetragonal crystal structure and the highest ambient-pressure Tc (128 K) among all cuprate superconductors with two CuO2 sheets in the primitive cell. Improvement in single-crystal synthesis was made possible by using self-designed high-pressure furnaces and a two-layer encapsulation method, and we demonstrate that the hole concentration can be homogeneously tuned in the underdoped region by post-growth annealing. Our electronic Raman scattering experiments reveal that the maximum of the d-wave superconducting gap increases from single-layer HgBa2CuO4 +x to double-layer Hg1212. In the same spectra, it is found that the characteristic energy of spin excitations, as manifested by the energy of the two-magnon signal, also increases in a nearly proportional fashion. This result is consistent with the idea that magnetic interactions are closely related to the Cooper pairing mechanism.

  13. High-Tc Superconductivity: Strong Indication of Filamentary-Chaotic Conductance and Possible Routes to Superconductivity Above Room Temperature

    CERN Document Server

    Otto, Hans Hermann

    2016-01-01

    The empirical relation of T_co(K)=2740/_c^4 between the transition temperature of optimum doped superconductors T_co and the mean cationic charge _c, a physical paradox, can be recast to strongly support fractal theories of high-T_c superconductors, thereby applying the finding that the optimum hole concentration of h^+ = 0.229 can be linked with the universal fractal constant delta_1 = 8.72109... of the renormalized Henon map. The transition temperature obviously increases steeply with a domain structure of ever narrower size, characterized by Fibonacci numbers. With this backing superconductivity above room temperature can be conceived for synthetic sandwich structures of _c less than 2+. For instance, composites of tenorite and cuprite respectively tenorite and CuI (CuBr, CuCl) onto AuCu alloys are proposed. This specification is suggested by previously described filamentary superconductivity of 'bulk' CuO_1-x samples. In addition, cesium substitution in the Tl-1223 compound is an option. A low mean cation...

  14. Field-dependent critical state of high-Tc superconducting strip simultaneously exposed to transport current and perpendicular magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Cun; He, An; Yong, Huadong; Zhou, Youhe, E-mail: zhouyh@lzu.edu.cn [Key Laboratory of Mechanics on Disaster and Environment in Western China attached to the Ministry of Education of China, and Department of Mechanics and Engineering Sciences, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)

    2013-12-15

    We present an exact analytical approach for arbitrary field-dependent critical state of high-T{sub c} superconducting strip with transport current. The sheet current and flux-density profiles are derived by solving the integral equations, which agree with experiments quite well. For small transport current, the approximate explicit expressions of sheet current, flux-density and penetration depth for the Kim model are derived based on the mean value theorem for integration. We also extend the results to the field-dependent critical state of superconducting strip in the simultaneous presence of applied field and transport current. The sheet current distributions calculated by the Kim model agree with experiments better than that by the Bean model. Moreover, the lines in the I{sub a}-B{sub a} plane for the Kim model are not monotonic, which is quite different from that the Bean model. The results reveal that the maximum transport current in thin superconducting strip will decrease with increasing applied field which vanishes for the Bean model. The results of this paper are useful to calculate ac susceptibility and ac loss.

  15. Separation of tc from Uranium and development of metallic Technetium waste forms

    Science.gov (United States)

    Mausolf, Edward John

    The isotope Technetium-99 (99Tc) is a major fission product of the nuclear industry. In the last decade, approximately 20 tons of 99Tc have been produced by the US nuclear industry. Due to its long half-life (t1/2 = 214,000 yr), beta radiotoxicity, and high mobility as pertechnetate [TcO4]-, Tc represents long-term concern to the biosphere. Various options have been considered to manage 99Tc. One of them is its separation from spent fuel, conversion to the metal and incorporation into a metallic waste form for long-term disposal. After dissolution of spent fuel in nitric acid and extraction of U and Tc in organic media, previously developed methods can be used to separate Tc from U, convert the separate Tc stream to the metal and reuse the uranium component of the fuel. A variety of metallic waste forms, ranging from pure Tc metal to ternary Tc alloys combined with stainless steel (SS) and Zr are proposed. The goal of this work was to examine three major questions: What is the optimal method to separate Tc from U? After separation, what is the most efficient method to convert the Tc stream to Tc metal? Finally, what is the corrosion behavior of Tc metal, Tc-SS alloys and Tc-Zr-SS alloys in 0.01M NaCl? The goal is to predict the long term behavior of Tc metallic waste in a hypothetical storage environment. In this work, three methods have been used to separate Tc from U: anionic exchange resin, liquid-liquid extraction and precipitation. Of the three methods studied, anionic exchange resins is the most selective. After separation of Tc from U, three different methods were studied to convert the Tc stream to the metal: thermal treatment under hydrogen atmosphere, electrochemical and chemical reduction of pertechnetate in aqueous media. The thermal treatment of the Tc stream under hydrogen atmosphere is the preferred method to produce Tc metal. After Tc metal is isolated, it will be incorporated into a metal host phase. Three different waste forms were produced for

  16. sup 99m Tc renal tubular function agents: Current status

    Energy Technology Data Exchange (ETDEWEB)

    Eshima, D.; Fritzberg, A.R.; Taylor, A. Jr. (Emory Univ. School of Medicine, Atlanta, GA (USA))

    1990-01-01

    Orthoiodohippuric (OIH) acid labeled with 131I is a widely used renal radiopharmaceutical agent and has been the standard radiopharmaceutical agent for the measurement of effective renal plasma flow (EPRF). Limitations to the routine clinical use of 131I OIH are related to the suboptimal imaging properties of the 131I radionuclide and its relatively high radiation dose. 123I has been substituted for 131I; however, its high cost and short shelf-life have limited its widespread use. Recent work has centered on the development of a new 99mTc renal tubular function agent, which would use the optimal radionuclidic properties and availability of 99mTc and combine the clinical information provided by OIH. The search for a suitable 99mTc renal tubular function agent has focused on the diamide dithiolate (N2S2), the paraaminohippuric iminodiacetic acid (PAHIDA), and the triamide mercaptide (N3S) donor ligand systems. To date, the most promising 99mTc tubular function agent is the N3S complex: 99mTc mercaptoacetyltriglycine (99mTc MAG3). Studies in animal models in diuresis, dehydration, acid or base imbalance, ischemia, and renal artery stenosis demonstrate that 99mTc MAG3 behaves similarly to 131I OIH. A simple kit formulation is available that yields the 99mTc MAG3 complex in high radiochemical purity. Studies in normal subjects and patients indicate that 99mTc MAG3 is an excellent 99mTc renal tubular agent, but its plasma clearance is only 50% to 60% that of OIH. In an effort to develop an improved 99mTc renal tubular function agent, changes have been made in the core N3S donor ligand system, but to date no agent has been synthesized that is clinically superior to 99mTc MAG3. 61 references.

  17. Evaluation of {sup 99m}Tc-glucarate as a breast cancer imaging agent in a xenograft animal model

    Energy Technology Data Exchange (ETDEWEB)

    Gambini, Juan Pablo [Nuclear Medicine Center, Clinical Hospital, University of Uruguay, Montevideo, 11600 (Uruguay); Cabral, Pablo [Nuclear Investigations Center, School of Science, University of Uruguay, Montevideo, 11400 (Uruguay); Alonso, Omar [Nuclear Medicine Center, Clinical Hospital, University of Uruguay, Montevideo, 11600 (Uruguay); Savio, Eduardo [Department of Radiochemistry, School of Chemistry, University of Uruguay, Montevideo, 11800 (Uruguay); Daibes Figueroa, Said [Research Service, Harry S. Truman Veterans Memorial Hospital, Columbia, MO 65201 (United States); Zhang Xiuli [Research Service, Harry S. Truman Veterans Memorial Hospital, Columbia, MO 65201 (United States); Department of Biochemistry, University of Missouri, Columbia, MO 65211 (United States); Ma Lixin [Research Service, Harry S. Truman Veterans Memorial Hospital, Columbia, MO 65201 (United States); Department of Radiology, University of Missouri, Columbia, MO 65212 (United States); Deutscher, Susan L. [Research Service, Harry S. Truman Veterans Memorial Hospital, Columbia, MO 65201 (United States); Department of Biochemistry, University of Missouri, Columbia, MO 65211 (United States); Quinn, Thomas P., E-mail: quinnt@missouri.ed [Research Service, Harry S. Truman Veterans Memorial Hospital, Columbia, MO 65201 (United States); Department of Biochemistry, University of Missouri, Columbia, MO 65211 (United States); Department of Radiology, University of Missouri, Columbia, MO 65212 (United States)

    2011-02-15

    Introduction: The use of [{sup 99m}Tc]glucarate has been reported as an infarct-avid agent with the potential for very early detection of myocardial infarction. [{sup 99m}Tc]Glucarate has also been postulated as an agent for non-invasive detection of tumors. The aim of our study was to develop a Glucarate kit and evaluate [{sup 99m}Tc]glucarate as a potential cancer imaging agent in female SCID mice bearing human MDA-MB-435 breast tumors. Methods: Glucarate in a kit formulation was labeled with {sup 99m}Tc and evaluated for radiolabelling efficiency and radiochemical purity. The Glucarate kit stability was assessed by monthly quality controls. The pharmacokinetics of [{sup 99m}Tc]glucarate were determined in female SCID mice bearing MDA-MB-435 human breast carcinoma tumors at 0.5, 1, 2, 4 and 24 h. Nuclear imaging studies were performed with a micro-single photon emission tomography (SPECT)/computed tomography (CT) system at 2 h post injection, while magnetic resonance imaging (MRI) was employed for tumor morphology analysis and metastatic deposit localization. Results: The Glucarate kits exhibited a stable shelf life of 6 months. [{sup 99m}Tc]Glucarate was obtained with radiochemical purity greater than 95%. Biodistribution studies demonstrated moderate tumor uptake coupled with high renal clearance. Tumor-to-muscle ratios were 4.85 and 5.14 at 1 and 4 h post injection. MRI analysis showed tumors with dense cellular growth and moderate central necrosis. [{sup 99m}Tc]Glucarate uptake in the primary MDA-MB-435 shoulder tumors and metastatic lesions were clearly visualized with micro-SPECT/CT imaging. Conclusions: Selective tumor uptake and rapid clearance from nontarget organs makes [{sup 99m}Tc]glucarate a potential agent for breast cancer imaging that awaits validation in a clinical trial.

  18. Direct {sup 99m}Tc labeling of Herceptin (trastuzumab) by {sup 99m}Tc(I) tricarbonyl ion

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W.-J.; Yen, C.-L.; Lo, S.-T.; Chen, K.-T. [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lo, J.-M. [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China)], E-mail: jmlo@mx.nthu.edu.tw

    2008-03-15

    By simply incubating Herceptin (trastuzumab) with [{sup 99m}Tc(CO){sub 3}(OH{sub 2}){sub 3}]{sup +} ion in saline, a significant yield of {sup 99m}Tc-labeled trastuzumab was found to be achievable. The effective labeling may be based on that trastuzumab is inherent with endogenous histidine group to which {sup 99m}Tc(I) tricarbonyl ion can be strongly bound. For practical {sup 99m}Tc labeling processing, trastuzumab was purified beforehand from the commercial product, Herceptin (Genentech) via size exclusion chromatography to remove the excipient, {alpha}-histidine and a high-labeled yield could be obtained by incubating the purified trastuzumab with [{sup 99m}Tc(CO){sub 3}(OH{sub 2}){sub 3}]{sup +}. Retention of bioactivity of the {sup 99m}Tc(I)-labeled trastuzumab was validated using a cell binding test.

  19. Preparation and physical properties of polycrystalline (Bi{sub 1{minus}x}Pb{sub x}){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} high {Tc} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Awan, M.S.; Maqsood, M.; Mirza, S.A.; Yousaf, M.; Maqsood, A. [Quaid-i-Azam Univ., Islamabad (Pakistan)

    1995-02-01

    (Bi{sub 1{minus}x}Pb{sub x}){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} (x = 0.3) high critical transition temperature ({Tc}) superconductors are synthesized by the solid-state reaction method in polycrystalline form. X-ray diffraction (XRD) studies, direct current (dc) electrical resistivity measurements, scanning electron microscopic (SEM) studies, critical current density measurements and zero-field alternating current (ac) susceptibility measurements are performed to investigate the physical changes, structural changes, and magnetic behavior of the superconducting samples. X-ray diffraction studies show that a high {Tc} phase exists with orthorhombic symmetry in the specimen. According to the XRD data, the lattice parameters of the high {Tc} phase were determined as a = 0.537(1) nm, b = 0.539(1) nm, and c = 3.70(1) nm. The compound exhibits a superconducting transition at 106 {plus_minus} 1 K for zero resistance. The ac susceptibility measurements in zero field confirm the dc electrical resistivity results; hence both support the XRD results. The particle size and structural changes as a function of the cold-pressing and aging effect are also reported.

  20. Impeding 99Tc(IV) mobility in novel waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Mal Soon; Um, Wooyong; Wang, Guohui; Kruger, Albert A.; Lukens, Wayne W.; Rousseau, Roger J.; Glezakou, Vassiliki Alexandra

    2016-06-30

    Technetium (99Tc) is a long-lived radioactive fission product whose mobility in the subsurface is largely governed by its oxidation state1. Immobilization of Tc in mineral substrates is crucial for radioactive waste management and environmental remediation. Tc(IV) incorporation in spinels2, 3 has been proposed as a novel method to increase Tc retention in glass waste forms. However, experiments with Tc-magnetite under high temperature and oxic conditions showed re-oxidation of Tc(IV) to volatile pertechnetate Tc(VII)O4-.4, 5 Here we address this problem with large-scale ab initio molecular dynamics simulations and propose that elevated temperatures, 1st row transition metal dopants can significantly enhance Tc retention in the order Co > Zn > Ni. Experiments with doped spinels at T=700 ºC provided quantitative confirmation of increased Tc retention in the same order predicted by theory. This work highlights the power of modern state-of-the-art simulations to provide essential insights and generate bottom-up design criteria of complex oxide materials at elevated temperatures.

  1. MgB2超导电性的发现及新一轮高临界温度超导研究热潮%DISCOVERY OF SUPERCONDUCTING MgB2 RENEWS INTEREST IN HIGH Tc SUPERCONDUCTORS

    Institute of Scientific and Technical Information of China (English)

    熊光成

    2001-01-01

    On January 10 J. Akimitsu(Aoyama Gakuin University)announced at asymposium in Japan that MgB2 is a BCS type superconductor with Tc = 39K. This discovery is causing new excitement in high temperature superconducting research.%2001年1月10日,在日本召开的学术会议上,AoyamaGakuin大学的J.Akimitsu教授宣布MgB2显现超导电性(Tc=39K).紧接着的一系列研究工作表明,MgB2属于BCS超导体.这些发现引起了新一轮高临界温度超导研究热潮.

  2. A study on hadron interactions through observation of cosmic-ray families of visible energy greater than 500 TeV in high mountain emulsion chambers

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, S. [Waseda Univ., Tokyo (Japan). Adv. Res. Center for Sci. and Eng.; Tamada, M. [Faculty of Science and Technology, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577 (Japan)

    1996-08-19

    The characteristics of hadron interactions are studied with emulsion chambers exposed at both Mt. Chacaltaya and the Pamirs. The total exposure is {approx}1330 m{sup 2} year. Event by event surveys on the shower configurations in a single family event were accomplished over the 75 cosmic-ray families in the highest energy range, i.e., visible energy greater than 500 TeV. Extraordinary characteristics of high energy shower clusters of small spread and the exotic type interactions, Centauro species, are discussed from the cosmic-ray-family phenomenological point of view. (orig.).

  3. Cherecteristic on lower carriers dencity in high Tc copper oxidie superconductors%高Tc铜氧化物超导体的低密度载流子特征

    Institute of Scientific and Technical Information of China (English)

    黄新民; 陈羽

    2014-01-01

    In this paper , the electronegative equalization principle is used to study the formation chemi-cal bond among the elements of the high Tc copper oxide superconductors .For the chemical bond formation , the lower carriers density is produced , witch is very strong affection the high Tc superconductivity .With the chemical bond , the electrons density in superconductors is distributed disproportionatel .The disproportionate characteristic form the different nature between the superconducting state and non-superconducting state .%用电负性均衡原理研究在高Tc 铜氧化物超导体中由于元素中有化学键的形成,形成了低密度载流子浓度并对超导电性产生了强烈的影响;由于元素之间形成化学键,电子密度的分布在超导材料中的不均匀性,使得超导材料中形成宏观物理性质不同的板块结构。

  4. Muscle localization of Tc-99m MDP after exertion

    Energy Technology Data Exchange (ETDEWEB)

    Valk, P.

    1984-09-01

    Very high muscle uptake of Tc-99m MDP was seen two days after the start of a program of vigorous weight-lifting exercises. Localization of Tc-99m bone tracer in muscle that has been damaged by exertion may be a more common phenomenon than is recognized at present.

  5. High-Tc superconductivity near the anion height instability in Fe-based superconductors: analysis of LaFeAsO(1-x)H(x).

    Science.gov (United States)

    Onari, Seiichiro; Yamakawa, Youichi; Kontani, Hiroshi

    2014-05-09

    The isostructural transition in the tetragonal phase with a sizable change in the anion height, is realized in heavily H-doped LaFeAsO and (La,P) codoped CaFe2As2. In these compounds, the superconductivity with higher Tc (40-50 K) is realized near the isostructural transition. To find the origin of the anion-height instability and the role in realizing the higher-Tc state, we develop the orbital-spin fluctuation theory by including the vertex correction. We analyze LaFeAsO(1-x)H(x) and find that the non-nematic orbital fluctuations, which induce the anion-height instability, are automatically obtained at x∼0.5, in addition to the conventional nematic orbital fluctuations at x∼0. The non-nematic orbital order triggers the isostructural transition, and its fluctuation would be a key ingredient to realize higher-Tc superconductivity of order 50 K.

  6. Recovering greater fungal diversity from pristine and diesel fuel contaminated Sub-Antarctic soil through cultivation using a high and a novel low nutrient approach

    Directory of Open Access Journals (Sweden)

    Belinda Carlene Ferrari

    2011-11-01

    Full Text Available Novel cultivation strategies for bacteria are widespread and are well described for recovering greater diversity from the hitherto unculturable majority. While similar approaches have not been demonstrated for fungi it has been suggested that of the 1.5 million estimated species less than 5% have been recovered into pure culture. Fungi are known to be involved in many degradative processes, including the breakdown of hydrocarbons, and it has been speculated that in Polar Regions they contribute significantly to bioremediation of soils contaminated with hydrocarbons. Given the biotechnological potential of fungi there is a need to increase efforts for greater species recovery, particularly from extreme environments such as sub-Antarctic Macquarie Island. In this study, like the hitherto unculturable bacteria, high concentrations of nutrients selected for predominantly different species to that recovered using low nutrient media. By combining both approaches to cultivation from contaminated and non-contaminated soils, 99 fungal species were recovered, including 42 yet unidentified species, several of which were isolated from soils containing high concentrations of diesel fuel. These novel species will now be characterized for their potential role in hydrocarbon degradation.

  7. Evaluation of Tc-99m leukocyte scan in the diagnosis of acute appendicitis

    Energy Technology Data Exchange (ETDEWEB)

    Butler, J.A.; Marcus, C.S.; Henneman, P.L.; Inkelis, S.H.; Wilson, S.E.

    1987-05-01

    A new /sup 99m/Tc Microlite leukocyte scan was performed in 38 patients to assess its value in the diagnosis of acute appendicitis. Autologous leukocytes are labeled with /sup 99m/Tc by inducing phagocytosis of /sup 99m/Tc albumin microcolloid particles. The advantages of this test over the standard indium-111 scan include superior imaging capability, a marked reduction (greater than 75%) in the radiation dose, and performance of the test including labeling, in less than 3 hr. Imaging is performed at 5-90 min postinjection of labeled cells. There were 19 male and 19 female patients with ages ranging from 10 to 80 years, in whom the diagnosis of appendicitis was indeterminate on clinical examination. Of the 13 of the 38 patients (34%) who came to surgery 12 had acute appendicitis. The WBC scan correctly identified 10 of the 12 cases of appendicitis. There were two false-negative studies. In the nonoperative group of 25 patients admitted for observation, 21 studies were reported as negative and four identified other sites of inflammation. All patients with a negative study have remained asymptomatic on follow-up. With a sensitivity of 83% (10/12) and a specificity of 100% (26/26) the /sup 99m/Tc leukocyte scan provides a rapid and highly accurate method for diagnosis of appendicitis in this preliminary study of patients with equivocal clinical exams.

  8. Novel (99m)Tc(III) Complexes [(99m)TcCl(CDO)(CDOH)2B-R] (CDOH2 = Cyclohexanedione Dioxime) Useful as Radiotracers for Heart Imaging.

    Science.gov (United States)

    Liu, Min; Fang, Wei; Liu, Shuang

    2016-11-16

    In this study, we evaluated seven new (99m)Tc(III) complexes [(99m)TcCl(CDO)(CDOH)2B-R] ((99m)Tc-2Fboroxime: R = 2-formylfuran-3-yl (2F); (99m)Tc-3Fboroxime: R = furan-3-yl (3F); (99m)Tc-5Fboroxime: R = 5-formyfuran-2-yl (5F); (99m)Tc-HPboroxime: R = 6-hydroxylpyridin-2-yl (HP); (99m)Tc-MPYboroxime: R = 5-methoxypyridin-3-yl (MPY); (99m)Tc-PMboroxime: R = 1,5-pyrimidin-3-yl (PM); and (99m)Tc-4PYboroxime: R = pyridin-4-yl (4PY)) for their potential as heart imaging agents. All new (99m)Tc(III) radiotracers except (99m)Tc-2Fboroxime were prepared with high radiochemical purity (RCP > 95%). The low RCP (∼75%) for (99m)Tc-2Fboroxime is most likely caused by steric hindrance from the 3-formyl group. Biodistribution and imaging studies were performed in SD rats. Planar image quantification was performed to compare their myocardial retention times. We found that the myocardial washout curves of new (99m)Tc(III) radiotracers were best fitted the biexponential decay function. The AUC (area under the curve) values followed the general trend: (99m)Tc-5Fboroxime (129 ± 6) > (99m)Tc-3Fboroxime (114 ± 11) > (99m)Tc-Teboroxime (104 ± 16) > (99m)Tc-MPYboroxime (92 ± 18) > (99m)Tc-4PYboroxime (77 ± 10) > (99m)Tc-PMboroxime (68 ± 14) ≈ (99m)Tc-HPboroxime (62 ± 14). The 2 min heart uptake values from biodistribution studies follow the ranking order of (99m)Tc-5Fboroxime (3.75 ± 0.15%ID/g) ≈ (99m)Tc-MPYboroxime (3.73 ± 0.24%ID/g) > (99m)Tc-PMboroxime (3.47 ± 0.15%ID/g) ≈ (99m)Tc-3Fboroxime ≈ (3.25 ± 0.77%ID/g). The 5 min heart uptake of (99m)Tc-5Fboroxime (3.91 ± 0.09%ID/g) was almost identical to its 2 min heart uptake (3.75 ± 0.15%ID/g), and its 15 min heart uptake value (2.83 ± 0.08%ID/g) compared well to the 2 min heart uptake of (99m)Tc-Teboroxime (3.00 ± 0.37%ID/g). It took ∼5 min for (99m)Tc-5Fboroxime to approach the 1 min heart uptake value of (99m)Tc-Teboroxime (∼3.5% ID/g) and ∼9.5 min to reach the 2 min heart uptake value of (99m)Tc

  9. High-fat diet-related stimulation of sweetness desire is greater in women than in men despite high vegetable intake.

    Science.gov (United States)

    Zhou, Bei; Yamanaka-Okumura, Hisami; Adachi, Chisaki; Kawakami, Yuka; Katayama, Takafumi; Takeda, Eiji

    2015-05-01

    To examine the effects of lunches with different dietary energy densities on food preferences between genders. Randomized crossover study. Participants were administered the following packed test meals once weekly on a specified day during six sessions: control (150 g of rice with a sautéed beef entrée containing 40 g of raw beef and 240 g of vegetables), high-meat/low-rice, low-vegetable, medium-fat/low-vegetable, high-fat and high-fat/low-vegetable meals. Subjective levels of sensory properties were assessed over time using visual analogue scales. University of Tokushima Graduate School, Tokushima, Japan. Sixty-five men and sixty-five women matched by age and BMI. Men showed significantly stronger desires for salty and fatty foods after meals (Pmeal, and increasing fat content under high-vegetable conditions caused a significant stimulated sweetness desire in women more than in men (Pmeal with 100 g of rice, sweetness desire was stronger in women (P=0.024), whereas no significant differences in sweetness desire were shown between genders after another low-energy-density control meal with 150 g of rice. Men had significantly stronger desires for salty and fatty foods, whereas women preferred sweet food after meals. The sweetness desire in women was stimulated by increasing fat content, even with a high vegetable intake. Low rice intake in a low-energy-density diet also caused a relative stimulation of sweetness desire in women.

  10. Imaging and biodistribution of ~(99)Tc~m labeled peptide high-binding VEGF receptor 3 in nude mice with ovarian cancer%~(99)Tc~m标记VEGFR-3高亲和融合多肽在荷人卵巢癌裸鼠体内的分布和显像研究

    Institute of Scientific and Technical Information of China (English)

    王玲; 梁志清; 侍立峰; 杨明福; 刘广元

    2009-01-01

    目的 研究~(99)Tc~m标记VEGFR-3高亲和融合肽(phage-SHSWHWLPNLRHYAS)在荷人卵巢癌裸鼠体内分布和放射免疫定位显像.方法 用NHS-MAG3为双功能鳌合剂,固相法合成多肽.~(99)Tc~m预亚锡直接标记法进行标记,纸层析法测定标记率.经尾静脉注射于荷瘤鼠体内,取不同时相进行SPECT显像,测定标记物在体内的分布情况并进行分析.结果 融合多肽的~(99)Tc~m标记率为95.27%,放射化学纯度为96%,放射性浓度24.6 MBq/ml.经鼠尾静脉注射后1 h,植瘤部位开始出现放射性浓集,肾脏、肝脏及膀胱组织也可见显像;注射后3 h肿瘤显像最清晰,每克组织注射百分剂量率(%ID/g)为(30.20±6.89).其余大部分脏器的T/NT值均达最高,最高为肌肉(13.13);注射后4 h肿瘤部位显像逐渐消退.对照组裸鼠的肿瘤部位始终未见显像.结论 筛选获得的VEGFR-3高亲和融合肽能够靶向荷瘤鼠体内肿瘤组织,实现肿瘤的靶向受体显像.%Objective To investigate the imaging and biodistribution of ~(99)Tc~m labeled peptide (phage-SHSWHWLPNLRHYAS) high-binding VEGF receptor 3 in nude mice with ovarian cancer. Methods We used NHS-MAG3 as the bifunctional chelating agent and synthesized the peptide above. It was completed with pre-stannous direct labeling by ~(99)Tc~m and then the labeling efficiency was determined by paper chromatography. The tumor bearing mice were injected via tail veins with radiolabeled peptide. The tumors were imaged with single photon emission computed tomography (SPECT). We measured and calculated the biodistribution of the radiolabeled peptide. Results The labeled rate was 95. 27% and the radiochemical purity was 96%. Under a SPECT apparatus, we observed tumor location image at 1 h post injection and the tumor images was the clearest at 3 h post injection, with the injected dose per gram of tissue (%ID/g) of (30. 20±6. 89) at the tumor sites. The tumor/muscle ratio was 13.13. Conclusion Our peptide can

  11. Sustained availability of 99mTc: possible paths forward.

    Science.gov (United States)

    Pillai, Maroor Raghavan Ambikalmajan; Dash, Ashutosh; Knapp, F F Russ

    2013-02-01

    The availability of (99m)Tc for single-photon imaging in diagnostic nuclear medicine is crucial, and current availability is based on the (99)Mo/(99m)Tc generator fabricated from fission-based molybdenum (F (99)Mo) produced using high enriched uranium (HEU) targets. Because of risks related to nuclear material proliferation, the use of HEU targets is being phased out and alternative strategies for production of both (99)Mo and (99m)Tc are being evaluated intensely. There are evidently no plans for replacement of the limited number of reactors that have primarily provided most of the (99)Mo. The uninterrupted, dependable availability of (99m)Tc is a crucial issue. For these reasons, new options being pursued include both reactor- and accelerator-based strategies to sustain the continued availability of (99m)Tc without the use of HEU. In this paper, the scientific and economic issues for transitioning from HEU to non-HEU are also discussed. In addition, the comparative advantages, disadvantages, technical challenges, present status, future prospects, security concerns, economic viability, and regulatory obstacles are reviewed. The international actions in progress toward evolving possible alternative strategies to produce (99)Mo or (99m)Tc are analyzed as well. The breadth of technologies and new strategies under development to provide (99)Mo and (99m)Tc reflects both the broad interest in and the importance of the pivotal role of (99m)Tc in diagnostic nuclear medicine.

  12. Investigation of four {sup 99m}Tc-labeled bacteriophages for infection-specific imaging

    Energy Technology Data Exchange (ETDEWEB)

    Rusckowski, Mary [Division of Nuclear Medicine, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655-0243 (United States)], E-mail: mary.rusckowski@umassmed.edu; Gupta, Suresh; Liu Guozheng; Dou Shuping; Hnatowich, Donald J. [Division of Nuclear Medicine, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655-0243 (United States)

    2008-05-15

    Introduction: This study investigated radiolabeled bacteriophages for specific detection of infection through gamma imaging. Previously, a {sup 99m}Tc-labeled M13 phage demonstrated specific binding for its host Escherichia coli in vitro and in mice through imaging. Methods: This study was extended to phages P22, E79, VD-13 and phage 60. Each was radiolabeled with {sup 99m}Tc using the chelator MAG{sub 3}, and were evaluated for binding to host and non-host bacteria in vitro and in a mouse infection model. Results: In vitro, each {sup 99m}Tc-phage bound to its host at least 4-fold higher than to non-host bacteria. For example, {sup 99m}Tc-E79 showed 10- to 20-fold greater binding to host Pseudomonas aeruginosa compared to non-host Escherichia coli and Salmonella enterica, and {sup 99m}Tc-phage 60 showed 20-fold greater binding to host Klebsiella pneumoniae over non-hosts. Mice received host or non-host bacteria in one thigh, and 3 h later, the {sup 99m}Tc-phages were administered intravenously. After a further 3 h, the tissues were counted. Liver accumulation was highest for {sup 99m}Tc-E79, averaging 39% compared to an average of 13% for the other {sup 99m}Tc-phages. Animals infected with host bacteria showed infected thigh/normal thigh ratios of 14.2 for {sup 99m}Tc-E79, 2.9 for {sup 99m}Tc-P22, 3.5 for {sup 99m}Tc-VD-13 and 2.1 for {sup 99m}Tc-phage 60. Conclusions: Although specific host binding was observed in vitro for each of these four {sup 99m}Tc-phages, only {sup 99m}Tc-E79 showed specificity for its host in an in vivo model.

  13. High Intensity Interval Training Leads to Greater Improvements in Acute Heart Rate Recovery and Anaerobic Power as High Volume Low Intensity Training

    Directory of Open Access Journals (Sweden)

    Thomas L. Stöggl

    2017-08-01

    Full Text Available The purpose of the current study was to explore if training regimes utilizing diverse training intensity distributions result in different responses on neuromuscular status, anaerobic capacity/power and acute heart rate recovery (HRR in well-trained endurance athletes.Methods: Thirty-six male (n = 33 and female (n = 3 runners, cyclists, triathletes and cross-country skiers [peak oxygen uptake: (VO2peak: 61.9 ± 8.0 mL·kg−1·min−1] were randomly assigned to one of three groups (blocked high intensity interval training HIIT; polarized training POL; high volume low intensity oriented control group CG/HVLIT applying no HIIT. A maximal anaerobic running/cycling test (MART/MACT was performed prior to and following a 9-week training period.Results: Only the HIIT group achieved improvements in peak power/velocity (+6.4%, P < 0.001 and peak lactate (P = 0.001 during the MART/MACT, while, unexpectedly, in none of the groups the performance at the established lactate concentrations (4, 6, 10 mmol·L−1 was changed (P > 0.05. Acute HRR was improved in HIIT (11.2%, P = 0.002 and POL (7.9%, P = 0.023 with no change in the HVLIT oriented control group.Conclusion: Only a training regime that includes a significant amount of HIIT improves the neuromuscular status, anaerobic power and the acute HRR in well-trained endurance athletes. A training regime that followed more a low and moderate intensity oriented model (CG/HVLIT had no effect on any performance or HRR outcomes.

  14. Lodging Update: Greater Boston

    Directory of Open Access Journals (Sweden)

    Rachel Roginsky

    2012-09-01

    Full Text Available Pinnacle Advisory Group provides an update of lodging industry performance in New England and Boston for the first half of 2012. While the New England region outpaced the nation, the specific story varies from state to state. Only Massachusetts and Vermont achieved REVPAR performance better than the national average. A review of the Greater Boston lodging market reveals that a healthy local economy and strong convention calendar, combined with a number of one-time events and limited new supply, boosted the local market in 2012. The outlook for 2013 in Greater Boston remains positive, with expectations of a 4.7% growth in REVPAR.

  15. Combined single crystal polarized XAFS and XRD at high pressure: probing the interplay between lattice distortions and electronic order at multiple length scales in high Tc cuprates

    Science.gov (United States)

    Fabbris, G.; Hücker, M.; Gu, G. D.; Tranquada, J. M.; Haskel, D.

    2016-07-01

    Some of the most exotic material properties derive from electronic states with short correlation length (~10-500 {\\AA}), suggesting that the local structural symmetry may play a relevant role in their behavior. Here we discuss the combined use of polarized x-ray absorption fine structure and x-ray diffraction at high pressure as a powerful method to tune and probe structural and electronic orders at multiple length scales. Besides addressing some of the technical challenges associated with such experiments, we illustrate this approach with results obtained in the cuprate La$_{1.875}$Ba$_{0.125}$CuO$_4$, in which the response of electronic order to pressure can only be understood by probing the structure at the relevant length scales.

  16. Beta decay of Tc-111 to Ru-111

    NARCIS (Netherlands)

    Pfeiffer, B; Lhersonneau, G; Dendooven, P; Honkanen, A; Huhta, M; Klockl, [No Value; Oinonen, M; Penttila, H; Persson, B.L.; Perajarvi, K; Wang, JC; Kratz, KL; Aysto, J

    1998-01-01

    The beta-decay of the very neutron-rich Tc-111 nucleus has been observed. A partial decay scheme of Ru-111 is presented, complementing the high-spin levels earlier reported in spontaneous fission work.

  17. [Greater trochanteric pain syndrome].

    Science.gov (United States)

    Gollwitzer, H; Opitz, G; Gerdesmeyer, L; Hauschild, M

    2014-01-01

    Greater trochanteric pain is one of the common complaints in orthopedics. Frequent diagnoses include myofascial pain, trochanteric bursitis, tendinosis and rupture of the gluteus medius and minimus tendon, and external snapping hip. Furthermore, nerve entrapment like the piriformis syndrome must be considered in the differential diagnosis. This article summarizes essential diagnostic and therapeutic steps in greater trochanteric pain syndrome. Careful clinical evaluation, complemented with specific imaging studies and diagnostic infiltrations allows determination of the underlying pathology in most cases. Thereafter, specific nonsurgical treatment is indicated, with success rates of more than 90 %. Resistant cases and tendon ruptures may require surgical intervention, which can provide significant pain relief and functional improvement in most cases.

  18. The Tribolium castaneum cell line TcA: a new tool kit for cell biology.

    Science.gov (United States)

    Silver, Kristopher; Jiang, Hongbo; Fu, Jinping; Phillips, Thomas W; Beeman, Richard W; Park, Yoonseong

    2014-10-30

    The red flour beetle, Tribolium castaneum, is an agriculturally important insect pest that has been widely used as a model organism. Recently, an adherent cell line (BCIRL-TcA-CLG1 or TcA) was developed from late pupae of the red flour beetle. Next generation transcriptome sequencing of TcA cells demonstrated expression of a wide variety of genes associated with specialized functions in chitin metabolism, immune responses and cellular and systemic RNAi pathways. Accordingly, we evaluated the sensitivity of TcA cells to dsRNA to initiate an RNAi response. TcA cells were highly sensitive to minute amounts of dsRNA, with a minimum effective dose of 100 pg/mL resulting in significant suppression of gene expression. We have also developed a plasmid containing two TcA-specific promoters, the promoter from the 40S ribosomal protein subunit (TC006550) and a bi-directional heat shock promoter (TcHS70) from the intergenic space between heat shock proteins 68a and b. These promoters have been employed to provide high levels of either constitutive (TC006550) or inducible (TcHS70) gene expression of the reporter proteins. Our results show that the TcA cell line, with its sensitivity to RNAi and functional TcA-specific promoters, is an invaluable resource for studying basic molecular and physiological questions.

  19. 99m Tc-labeled heparin test in orthopaedic surgery

    Energy Technology Data Exchange (ETDEWEB)

    Bouvier, J.F.; Lafon, J.C.; Colin, M.; Chatelut, J.; Beaubatie, F. (Hopital Universitaire Dupuytren, Limoges (France))

    1983-06-30

    99m Tc-labeled heparin test was performed for early detection of phlebitis or pulmonary embolism after orthopaedic prothesis. Heparinic treatment and surgery per se were demonstrated to have no effect on the results. If this test demonstrates a statistical difference for pathologic patients, it is of greater value to consider ratio between rates before and after intervention.

  20. Impeding 99Tc(IV) mobility in novel waste forms

    Science.gov (United States)

    Lee, Mal-Soon; Um, Wooyong; Wang, Guohui; Kruger, Albert A.; Lukens, Wayne W.; Rousseau, Roger; Glezakou, Vassiliki-Alexandra

    2016-06-01

    Technetium (99Tc) is an abundant, long-lived radioactive fission product whose mobility in the subsurface is largely governed by its oxidation state. Tc immobilization is crucial for radioactive waste management and environmental remediation. Tc(IV) incorporation in spinels has been proposed as a novel method to increase Tc retention in glass waste forms during vitrification. However, experiments under high-temperature and oxic conditions show reoxidation of Tc(IV) to volatile pertechnetate, Tc(VII). Here we examine this problem with ab initio molecular dynamics simulations and propose that, at elevated temperatures, doping with first row transition metal can significantly enhance Tc retention in magnetite in the order Co>Zn>Ni. Experiments with doped spinels at 700 °C provide quantitative confirmation of the theoretical predictions in the same order. This work highlights the power of modern, state-of-the-art simulations to provide essential insights and generate theory-inspired design criteria of complex materials at elevated temperatures.

  1. Significantly greater triglyceridemia in Black African compared to White European men following high added fructose and glucose feeding: a randomized crossover trial.

    Science.gov (United States)

    Goff, Louise M; Whyte, Martin B; Samuel, Miriam; Harding, Scott V

    2016-09-02

    Black African (BA) populations are losing the cardio-protective lipid profile they historically exhibited, which may be linked with increasing fructose intakes. The metabolic effects of high fructose diets and how they relate to blood lipids are documented for Caucasians, but have not been described in BA individuals. The principle objective of this pilot study was to assess the independent impacts of high glucose and fructose feeding in men of BA ancestry compared to men of White European (WE) ancestry on circulating triglyceride (TG) concentrations. Healthy males, aged 25-60 years, of BA (n = 9) and WE (n = 11) ethnicity were randomly assigned to 2 feeding days in a crossover design, providing mixed nutrient meals with 20 % total daily caloric requirements from either added glucose or fructose. Circulating TG, non-esterified fatty acids (NEFA), glucose, insulin and C-peptide were measured over two 24-h periods. Fasting TGs were lower in BAs than WEs on the fructose feeding day (p fructose feeding to increase in both BA (baseline median fasting: 0.80, IQR 0.6-1.1 vs 24-h median post-fructose: 1.09, 0.8-1.4 mmol/L; p = 0.06) and WE (baseline median fasting 1.10, IQR 0.9-1.5 vs 24-h median post-fructose: 1.16, IQR 0.96-1.73 mmol/L; p = 0.06). Analysis within ethnic group demonstrated that in TG iAUC was significantly higher in BA compared to WE on both glucose (35, IQR 11-56 vs -4, IQR -10-1 mmol/L/min; p = 0.004) and fructose (48, IQR 15-68 vs 13, IQR -7-38 mmol/L/min; p = 0.04). Greater suppression of postprandial NEFA was evident in WE than BA after glucose feeding (-73, IQR -81- -52 vs -26, IQR -48- -3 nmol/L/min; p = 0.001) but there was no ethnic difference following fructose feeding. Understanding the metabolic effects of dietary acculturation and Westernisation that occurs in Black communities is important for developing prevention strategies for chronic disease development. These data show postprandial

  2. Novel HIV IL-4R antagonist vaccine strategy can induce both high avidity CD8 T and B cell immunity with greater protective efficacy.

    Science.gov (United States)

    Jackson, Ronald J; Worley, Matthew; Trivedi, Shubhanshi; Ranasinghe, Charani

    2014-09-29

    We have established that the efficacy of a heterologous poxvirus vectored HIV vaccine, fowlpox virus (FPV)-HIV gag/pol prime followed by attenuated vaccinia virus (VV)-HIV gag/pol booster immunisation, is strongly influenced by the cytokine milieu at the priming vaccination site, with endogenous IL-13 detrimental to the quality of the HIV specific CD8+ T cell response induced. We have now developed a novel HIV vaccine that co-expresses a C-terminal deletion mutant of the mouse IL-4, deleted for the essential tyrosine (Y119) required for signalling. In our vaccine system, the mutant IL-4C118 can bind to IL-4 type I and II receptors with high affinity, and transiently prevent the signalling of both IL-4 and IL-13 at the vaccination site. When this IL-4C118 adjuvanted vaccine was used in an intranasal rFPV/intramuscular rVV prime-boost immunisation strategy, greatly enhanced mucosal/systemic HIV specific CD8+ T cells with higher functional avidity, expressing IFN-γ, TNF-α and IL-2 and greater protective efficacy were detected. Surprisingly, the IL-4C118 adjuvanted vaccines also induced robust long-lived HIV gag-specific serum antibody responses, specifically IgG1 and IgG2a. The p55-gag IgG2a responses induced were of a higher magnitude relative to the IL-13Rα2 adjuvant vaccine. More interestingly, our recently tested IL-13Rα2 adjuvanted vaccine which only inhibited IL-13 activity, even though induced excellent high avidity HIV-specific CD8+ T cells, had a detrimental impact on the induction of gag-specific IgG2a antibody immunity. Our observations suggest that (i) IL-4 cell-signalling in the absence of IL-13 retarded gag-specific antibody isotype class switching, or (ii) IL-13Rα2 signalling was involved in inducing good gag-specific B cell immunity. Thus, we believe our novel IL-4R antagonist adjuvant strategy offers great promise not only for HIV-1 vaccines, but also against a range of chronic infections where sustained high quality mucosal and systemic T and B

  3. A novel ternary ligand system useful for preparation of cationic (99m)Tc-diazenido complexes and (99m)Tc-labeling of small biomolecules.

    Science.gov (United States)

    Kim, Young-Seung; He, Zhengjie; Hsieh, Wen-Yuan; Liu, Shuang

    2006-01-01

    This report describes a novel ternary ligand system composed of a phenylhydrazine, a crown ether-containing dithiocarbamate (DTC), and a PNP-type bisphosphine (PNP). The combination of three different ligands with (99m)Tc results in cationic (99m)Tc-diazenido complexes, [(99m)Tc(NNAr)(DTC)(PNP)]+, with potential radiopharmaceuticals for heart imaging. Synthesis of cationic (99m)Tc-diazenido complexes can be accomplished in two steps. For example, the reaction of phenylhydrazine with (99m)TcO4- at 100 degrees C in the presence of excess stannous chloride and 1,2-diaminopropane-N,N,N',N'-tetraacetic acid (PDTA) results in the [(99m)Tc(NNPh)(PDTA)n] intermediate, which then reacts with sodium N-(dithiocarbamato)-2-aminomethyl-15-Crown-5 (L4) and N,N-bis[2-(bis(3-ethoxypropyl)phosphino)ethyl]ethoxyethylamine (PNP6) at 100 degrees C for 15 min to give the complex, [(99m)Tc(NNPh)(L4)(PNP6)]+ in high yield (>90%). Cationic complexes [(99m)Tc(NNPh)(DTC)(PNP)]+ are stable for > or = 6 h. Their composition was determined to be 1:1:1:1 for Tc:NNPh:DTC:PNP using the mixed-ligand experiments on the tracer ((99m)Tc) level and was further confirmed by the ESI-MS spectral data of a model compound [Re(NNPh)(L4)(L6)]+. It was found that both DTCs and bisphosphines have a significant impact on the lipophilicity of their cationic (99m)Tc-diazenido complexes. Results from a (99m)Tc-labeling efficiency experiment showed that 4-hydrazinobenzoic acid (HYBA) might be useful as a bifunctional coupling agent for (99m)Tc-labeling of small biomolecules. However, the (99m)Tc-labeling efficiency of HYBA is much lower than that of 6-hydrazinonicotinic acid (HYNIC) with tricine and trisodium triphenylphosphine-3,3',3''-trisulfonate (TPPTS) as coligands.

  4. Magnesium potassium phosphate ceramic for {sup 99}Tc immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D. [Energy Technology Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)]. E-mail: dsingh@anl.gov; Mandalika, V.R. [Energy Technology Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Parulekar, S.J. [Department of Chemical and Environmental Engineering, Illinois Institute of Technology, Chicago, IL 60616 (United States); Wagh, A.S. [Energy Technology Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)]. E-mail: wagh@anl.gov

    2006-02-01

    Technetium-99, present in the US Department of Energy's (DOE) high-level waste (HLW) as a by-product of fission reactions, poses a serious environmental threat because it has a long half-life, is highly mobile in its soluble Tc{sup 7+} oxidation state and is volatile at high temperatures. Magnesium potassium phosphate (MKP) ceramics have been developed to treat {sup 99}Tc that has been partitioned and eluted from simulated high-level tank wastes by means of sorption processes. Waste forms were fabricated by adding MKP binder and a reducing agent (SnCl{sub 2}) to the {sup 99}Tc-containing aqueous waste. In addition, waste forms were fabricated by first precipitating {sup 99}Tc from the waste and subsequently solidifying it in MKP. {sup 99}Tc loadings in the waste forms were as high as 900 ppm by weight. Waste form performance was established through various strength, leaching, and durability tests. Long-term leaching studies, as per the ANS 16.1 procedure, showed leachability indices between 11 and 14 for {sup 99}Tc under ambient conditions. The normalized leach rate for {sup 99}Tc, according to the product consistency test, was as low as 1.1 x 10{sup -3} g/m{sup 2} d. The waste forms exhibited a compressive strength of {approx}30 MPa and were durable in an aqueous environment. Containment of {sup 99}Tc in MKP ceramics is believed to be due to a combination of appropriate reducing environment (determined from Eh-pH measurements) and microencapsulation in a dense matrix.

  5. sup(99m)Tc-Ethylenediamine-N, N-diacetic acid. A radiopharmaceutical with tumor affinity

    Energy Technology Data Exchange (ETDEWEB)

    Imoto, Takeshi (Kyushu Univ., Fukuoka (Japan). Faculty of Medicine)

    1984-05-01

    sup(99m)Tc-Ethylenediamine-N, N-Diacetic Acid (sup(99m)Tc-EDDA), a compound having affinity for tumors was evaluated, and the results were as follows. 1) sup(99m)Tc-EDDA accumulated in experimentally-induced tumors. The tumor/tissue ratio (%g/dose) of sup(99m)Tc-EDDA was greater than that of /sup 67/Ga-citrate, especially with Ehrlich ascites tumors. 2) sup(99m)Tc-EDDA accumulated mainly in the nuclear components of tumor cells. 3) No acute toxic effects of EDDA were observed in mice, rabbits or in volunteers. 4) The sup(99m)Tc-EDDA image was positive in 72 % of clinical examinations of lung cancer. The sup(99m)Tc-EDDA did not accumulate in the liver, and this suggests that tumor near the liver may be more easily detected with sup(99m)Tc-EDDA than with /sup 67/Ga-citrate. 5) In some cases sup(99m)Tc-EDDA accumulated in mammary glands (nipples) and in pleural effusions (pleuritis), though the mechanism of which was obscure. 6) sup(99m)Tc-EDDA is a good agent for detecting malignant tumors.

  6. Undoped high-Tc superconductivity in T'-La1.8Eu0.2CuO4+δ revealed by 63,65Cu and 139La NMR: Bulk superconductivity and antiferromagnetic fluctuations

    Science.gov (United States)

    Fukazawa, Hideto; Ishiyama, Seiya; Goto, Masato; Kanamaru, Shuhei; Ohashi, Kohki; Kawamata, Takayuki; Adachi, Tadashi; Hirata, Michihiro; Sasaki, Takahiko; Koike, Yoji; Kohori, Yoh

    2017-10-01

    We performed 63,65Cu and 139La NMR measurements of T'-La1.8Eu0.2CuO4+δ (T'-LECO) with the Nd2CuO4-type structure (so-called T'-structure). As a result, we detected the 63,65Cu NMR signal under finite magnetic fields and found superconductivity without antiferromagnetic (AF) order only in the reduced T'-LECO, where excess apical oxygen atoms are properly removed. This indicates that the intrinsic ground state of the ideal T'-LECO is a paramagnetic and superconducting (SC) state. Below Tc, the Knight shift was found to rapidly decrease, which indicates the emergence of bulk superconductivity due to spin-singlet Cooper pairs in the reduced T'-LECO. In the SC state of the reduced T'-LECO, moreover, a characteristic temperature dependence of the spin-lattice relaxation rate 1/T1 was observed, which implies the existence of nodal lines in the SC gap. These findings suggest that the superconductivity in the reduced T'-LECO probably has d-wave symmetry. In the normal state of the reduced T'-LECO, on the other hand, AF fluctuations were found to exist from the temperature dependence of 1/T1T, though no clear pseudogap behavior was observed. This suggests that the AF correlation plays a key role in the superconductivity of undoped high-Tc cuprate superconductors with the T'-structure.

  7. GASIFICATION TEST RUN TC06

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services, Inc.

    2003-08-01

    This report discusses test campaign TC06 of the Kellogg Brown & Root, Inc. (KBR) Transport Reactor train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Reactor is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or a gasifier using a particulate control device (PCD). The Transport Reactor was operated as a pressurized gasifier during TC06. Test run TC06 was started on July 4, 2001, and completed on September 24, 2001, with an interruption in service between July 25, 2001, and August 19, 2001, due to a filter element failure in the PCD caused by abnormal operating conditions while tuning the main air compressor. The reactor temperature was varied between 1,725 and 1,825 F at pressures from 190 to 230 psig. In TC06, 1,214 hours of solid circulation and 1,025 hours of coal feed were attained with 797 hours of coal feed after the filter element failure. Both reactor and PCD operations were stable during the test run with a stable baseline pressure drop. Due to its length and stability, the TC06 test run provided valuable data necessary to analyze long-term reactor operations and to identify necessary modifications to improve equipment and process performance as well as progressing the goal of many thousands of hours of filter element exposure.

  8. Asialoglycoprotein receptor targeted imaging using Tc-99m galactosylated chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Kim, E. M.; Jeong, H. J.; Kim, B. C.; Kim, C. K [Wonkang University College of Medicine, Iksan (Korea, Republic of)

    2004-07-01

    The asialoglycoprotein receptor (ASGP-R) is expressed on liver hepatocytes. Chitosan conjugates of galactose have shown to be specifically taken up by liver parenchymal cells via ASGP-R. In this study, Tc-99m hydrazino nicotinamide (HYNIC)-galactosylated chitosan (HYNIC-GC) was synthesized and evaluated as a targeted agent for the imaging of hepatocytes. GC was obtained after coupling of lactobionic acid as the galactose moiety and coupled with HYNIC. HYNIC-GC was radiolabeled with Tc-99m using stannous chloride and tricine as reducing agent and coligand respectively. Hepatic uptake property of Tc-99m HYNIC-GC was studied in female Balb/C mouse. Tc-99m HYNIC--GC and Tc-99m HYNIC-Chitosan as a control were intravenously injected into mice. Receptor binding was identified by coinjection with 50 mM and 80mM free galactose respectively. Biodistribution was determined at three different time points. The level of galactose substitution was 7.6%. Labeling efficiency was >90% both in vitro and serum up to 24 h. Tc-99m HYNIC-GC injected via tail vein of mice showed high selectivity of liver. On the other hands, Tc-99m HC without galactose group showed low uptake (Fig. 1A, 1B). Hepatic uptake of Tc-99m HYNIC-GC was dramatically blocked by 50 mM and 80 mM free galactose coinjection (Fig. 1C, 1D). The liver accumulated about 14 percent injected dose per gram (%ID/g) up to 120 min after injection. Tc-99m HYNIC-GC showed specific and rapid targeting to liver. It is a promising specific radiopharmaceutical with potential applications in the imaging of liver parenchymal cells.

  9. Enhanced 99 Tc retention in glass waste form using Tc(IV)-incorporated Fe minerals

    Energy Technology Data Exchange (ETDEWEB)

    Um, Wooyong; Luksic, Steven A.; Wang, Guohui; Saslow, Sarah; Kim, Dong-Sang; Schweiger, Michael J.; Soderquist, Chuck Z.; Bowden, Mark E.; Lukens, Wayne W.; Kruger, Albert A.

    2017-11-01

    Technetium (99Tc) immobilization by doping into iron oxide mineral phases may alleviate the problems with Tc volatility during vitrification of nuclear waste. Reduced Tc, Tc(IV), substitutes for Fe(III) in the crystal structure by a process of Tc reduction from Tc(VII) to Tc(IV) followed by co-precipitation of Fe oxide minerals. Two Tc-incorporated Fe minerals (Tc-goethite and Tc-magnetite/maghemite) were prepared and tested for Tc retention in glass melt samples at temperatures between 600 – 1,000 oC. After being cooled, the solid glass specimens prepared at different temperatures were analyzed for Tc oxidation state using Tc K-edge XANES. In most samples, Tc was partially oxidized from Tc(IV) to Tc(VII) as the melt temperature increased. However, Tc retention in glass melt samples prepared using Tc-incorporated Fe minerals were moderately higher than in glass prepared using KTcO4 because of limited and delayed Tc volatilization.

  10. Spectral investigation of hot-spot and cavity resonance effects on the terahertz radiation emitted from high-Tc superconducting Bi2Sr2CaCu2O8+δ single crystal mesa structures

    Science.gov (United States)

    Kadowaki, Kazuo; Watanabe, Chiharu; Minami, Hidetoshi; Yamamoto, Takashi; Kashiwagi, Takanari; Klemm, Richard

    2014-03-01

    Terahertz (THz) electromagnetic radiation emitted from high-Tc superconducting Bi2Sr2CaCu2O8+δ mesa structures in the case of single mesa and series-connected mesas is investigated by the FTIR spectroscopic technique while observing its temperature distribution simultaneously by a SiC photoluminescence technique. Changing the bias level, sudden jumps of the hot-spot position were clearly observed. Although the radiation intensity changes drastically associated with the jump of the hot spot position, the frequency is unaffected as long as the voltage per junction is kept constant. Since the frequency of the intense radiation satisfies the cavity resonance condition, we confirmed that the cavity resonance is of primarily importance for the synchronization of whole intrinsic Josephson junctions in the mesa for high power radiation. This work was supported in part by the Grant-in-Aid for challenging Exploratory Research, the Ministry of Education, Culture, Sports, Science & Technology (MEXT).

  11. Clinical investigation of accumulation process of {sup 99m}Tc-HMDP and -MDP in bone

    Energy Technology Data Exchange (ETDEWEB)

    Matumoto, Takahiro [Health Insurance Naruto Hospital, Tokushima (Japan); Miyoshi, Hirokazu; Satou, Kazuo; Kishi, Taro; Yoshino, Tomio; Nishitani, Hiromu

    2000-06-01

    The accumulation process in bone of {sup 99m}Tc-hydroxymethylene diphosphonate ({sup 99m}Tc-HMDP) and {sup 99m}Tc-methylene diphosphonate ({sup 99m}Tc-MDP) was examined on 9 subjects (5 for {sup 99m}Tc-HMDP and 4 for {sup 99m}Tc-MDP). {sup 99m}Tc compounds in blood were analyzed with radio-thinlayer chromatography, radioactivity was measured using a scintillation counter, and the uptake of both {sup 99m}Tc diphosphonates in bone was examined by scintigraphy. The amounts of {sup 99m}Tc-HMDP and MDP compounds disappeared from blood for 2 h after injection were 83% and 87%, respectively, and these were almost unchanged even after 3 h. While the greater part of {sup 99m}TcO{sub 4}{sup -} contained in both diphosphonates was disappeared from blood, the small amounts of unknown {sup 99m}Tc compounds were produced in blood. The ratio of the radioactivity of {sup 99m}Tc-HMDP in lumbar vertebra to soft tissue near bone was 1.5{+-}0.5 after about 3 h, showing that equilibrium occurred in the process of the accumulation in bone, and good scintigrams were depicted in all the cases. These results suggest that the accumulation in bone of both {sup 99m}Tc diphosphonates may be by both fast chemical absorption onto the surface of the hydroxyapatite in bone and slow uptake mediated through osteoblast-like cells and organic matters. (author)

  12. Spectroscopic Properties of Tc(I) Tricarbonyl Species Relevant to the Hanford Tank Waste

    Energy Technology Data Exchange (ETDEWEB)

    Levitskaia, Tatiana G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Andersen, Amity [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chatterjee, Sayandev [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hall, Gabriel B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Walter, Eric D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Washton, Nancy M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-12-04

    Technetium-99 (Tc) exists predominately in soluble forms in the liquid supernatant and salt cake fractions of the nuclear tank waste stored at the U.S. DOE Hanford Site. In the strongly alkaline environments prevalent in the tank waste, its dominant chemical form is pertechnetate (TcO4-, oxidation state +7). However, attempts to remove Tc from the Hanford tank waste using ion-exchange processes specific to TcO4- only met with limited success, particularly processing tank waste samples containing elevated concentrations of organic complexants. This suggests that a significant fraction of the soluble Tc can be present as non-pertechnetate low-valent Tc (oxidation state < +7) (non-pertechnetate). The chemical identities of these non-pertechnetate species are poorly understood. Previous analysis of the SY-101 and SY-103 tank waste samples provided strong evidence that non-pertechnetate can be comprised of [Tc(CO)3]+ complexes containing Tc in oxidation state +1 (Lukens et al. 2004). During the last two years, our team has expanded this work and demonstrated that high-ionic-strength solutions typifying tank waste supernatants promote oxidative stability of the [Tc(CO)3]+ species (Rapko et al. 2013; Levitskaia et al. 2014). It also was observed that high-ionic-strength alkaline matrices stabilize Tc(VI) and potentially Tc(IV) oxidation states, particularly in presence organic chelators, suggesting that the relevant Tc compounds can serve as important redox intermediates facilitating the reduction of Tc(VII) to Tc(I). Designing strategies for effective Tc processing, including separation and immobilization, necessitates understanding the molecular structure of these non-pertechnetate species and their identification in the actual tank waste samples. To-date, only limited information exists regarding the nature and characterization of the Tc(I), Tc(IV), and Tc(VI) species. One objective of this project is to

  13. Study on 99mTc-MAG3 and 99mTc-DMSA renal accumulation using in vitro cellular model.

    Science.gov (United States)

    Nový, Zbynĕk; Mandíková, Jana; Trejtnar, Frantisek

    2011-02-01

    Mercaptoacetyltriglycine (MAG3) and dimercaptosuccinic acid (DMSA) labelled with technetium-99m belongs to standard renal radiodiagnostics. However, the renal transport mechanisms responsible for their high renal uptake have not been fully explained. In addition, no in vitro experimental study comparing the renal uptake of these radiopharmaceuticals at the cellular level has not been performed. The investigation compared the 99mTc-MAG3 and 99mTc-DMSA renal uptake using primary rat renal cells and evaluated contribution of active and passive transport processes to the renal accumulation. The renal cells were isolated from the rat kidneys by means of the two-phase collagenase perfusion method. The used experimental model showed to be useful tool for such type of investigation. The results documented significant quantitative and qualitative differences in the accumulation of 99mTc-DMSA and 99mTc-MAG3 in the rat isolated cells. The found experimental data indicated several times higher uptake of 99mTc-MAG3 than that found in 99mTc-DMSA. 99mTc-MAG3 cellular uptake was substantially decreased when active, energy-dependent processes were inhibited. However, 99mTc-DMSA accumulation in the renal cells demonstrated only a minor dependency on energy. These findings demonstrate a very different character of the membrane transport determining 99mTc-DMSA and 99mTc-MAG3 renal accumulation.

  14. Comparative biological evaluation between {sup 99m}Tc tricarbonyl and {sup 99m}Tc-Sn(II) levosalbutamol as a β{sub 2}-adrenoceptor agonist

    Energy Technology Data Exchange (ETDEWEB)

    Sanad, Mahmoud H. [Atomic Energy Authority, Cairo (Egypt). Labeled Compounds Dept.; Borai, Emad H. [Atomic Energy Authority, Cairo (Egypt). Analytical Chemistry Dept.

    2015-07-01

    This study describes the comparison between {sup 99m}Tc-tricarbonyl and {sup 99m}Tc-Sn (II) levosalbutamol as a β{sub 2}-adrenoceptors radiopharmaceutical and evaluation of their different biological characteristics using experimental animals. Levosalbutamol was labeled firstly with {sup 99m}Tc in the presence of SnCl{sub 2} . 2H{sub 2}O as a reducing agent under the optimum conditions: pH 8, 50 μg SnCl{sub 2} . 2H{sub 2}O, room temperature, 40 μg levosalbutamol and 30 min reaction time to give a maximum radiochemical yield of 98 ± 0.1%. The obtained {sup 99m}Tc-levosalbutamol was stable for a time up to 8 h. Secondly, {sup 99m}Tc-tricarbonyl ([{sup 99m}Tc(CO){sub 3}(H{sub 2}O){sub 3}]{sup +}) levosalbutamol was prepare under 30 min heating at 100 C. Labeling yield and stability were analyzed by high performance liquid chromatography (labeling yield >99% and stability for 8 h). Biodistribution investigation showed that, the maximum uptake ratio of the {sup 99m}Tc-levosalbutamol ({sup 99m}Tc-Lev) between lung and heart was 2.34 ± 0.62 % of the injected activity/g tissue organ, at 30 min post-injection. But in case of {sup 99m}Tc-tricarbonyl levosalbutamol ({sup 99m}Tc-tricarbonyl Lev) the maximum uptake ratio was 3.6 ± 0.11 of the injected activity/g tissue organ, at 30 min post-injection. This indicates that {sup 99m}Tc-tricarbonyl levosalbutamol was more selective for lung β{sub 2}-adrenoceptors than {sup 99m}Tc-levosalbutamol. These results introduce {sup 99m}Tc-tricarbonyl levosalbutamol as a novel potential radiopharmaceutical for lung imaging.

  15. Availability of {sup 99}Tc in undisturbed soil cores

    Energy Technology Data Exchange (ETDEWEB)

    Denys, Sebastien; Echevarria, Guillaume E-mail: guillaume.echevarria@ensaia.inpl-nancy.fr; Florentin, Louis; Leclerc-Cessac, Elisabeth; Morel, Jean-Louis

    2003-07-01

    Models for safety assessment of radioactive waste repositories need accurate values of the soil-to-plant transfer of radionuclides. In oxidizing environments, {sup 99}Tc is expected to occur as pertechnetate ({sup 99}TcO{sub 4}{sup -}). Due to its high mobility, leaching of this element in the field might be important, potentially affecting the reliability of estimated transfer parameters of {sup 99}Tc as measured in closed experimental systems such as hydroponics or pot experiments. The aim of this experiment was to measure the leaching of {sup 99}Tc in undisturbed irrigated soil cores under cultivation as well as plant uptake and to study the possible competition between the two transfer pathways. Undisturbed soil cores (50x50 cm) were sampled from a Rendzic Leptosol (R), a colluvial Fluvic Cambisol (F) and a Dystric Cambisol (D) using PVC tubes (three cores sampled per soil type). Each core was equipped with a leachate collector at the bottom, allowing the monitoring of {sup 99}Tc leaching through the cores. Cores were placed in a greenhouse and maize (Zea mays L., cv. DEA, Pioneer[reg]) was sown. After 135 d, maize was harvested and radioactivity determined in both plant and water samples. Results showed that during the growing period, leaching of {sup 99}Tc was limited, due to the high evapotranspiration rate of maize. After harvest, leaching of {sup 99}Tc went on because of the absence of evapotranspiration. Effective uptake (EU) of {sup 99}Tc in leaves and grains was calculated. EU reached 70% of the input in the leaves and was not significantly different among soils. These results confirmed those obtained from pot experiments, even though leaching was allowed to occur in close-to-reality hydraulical conditions. As a consequence, it was concluded that pot experiments are an adequate surrogate for more complex 'close-to-reality' experimental systems for measuring transfer factors.

  16. Internal static electric and magnetic field at the copper cite in a single crystal of the electron-doped high-Tc superconductor Pr1.85Ce0.15CuO4 -y

    Science.gov (United States)

    Wu, Guoqing; Zamborszky, F.; Reyes, A. P.; Kuhns, P. L.; Greene, R. L.; Clark, W. G.

    2014-12-01

    We report 63 ,65Cu -NMR spectroscopy and Knight shift measurements on a single crystal of the electron-doped high-Tc superconductor Pr1.85Ce0.15CuO4 -y with an applied magnetic field (H ) up to 26.42 T. A very small NQR frequency is obtained with the observation of the spectrum, which shows an extremely wide continuous distribution of it that becomes significantly narrower below 20 K at H ∥c where the superconductivity is completely suppressed, indicating a significant change in the charge distribution at the Cu site, while the corresponding change at H ⊥c is negligible when the superconductivity is present or not fully suppressed. The Knight shift and central linewidth are proportional to the applied magnetic field with a high anisotropy. We find that the magnitude of the internal static magnetic field at the copper is dominated by the anisotropic Cu2 + 3 d orbital contributions, while its weak temperature dependence is mainly determined by the isotropic contact hyperfine coupling to the paramagnetic Pr3 + spins, which also gives rise to the full distribution of the internal static magnetic field at the copper for H ⊥c . This internal static electric and magnetic field environment at the copper is very different from that in the hole-doped cuprates, and may provide new insight into the understanding of high-Tc superconductivity. Other experimental techniques are needed to verify whether the observed significant narrowing of the charge distribution at the Cu site with H ∥c is caused by the charge ordering [E. H. da Silva Neto et al., Science (to be published, 2014)] or a new type of charge modulation.

  17. Getters for Tc and I Removal from Liquid Waste

    Science.gov (United States)

    Qafoku, N. P.; Asmussen, M.; Lawter, A.; Neeway, J.; Smith, G.

    2015-12-01

    A cementitious waste form, Cast Stone, is being evaluated as a possible supplemental waste form for the low activity waste (LAW) at the Hanford Site, which contains significant amounts of radioactive 99Tc and 129I, as part of the tank waste cleanup mission. To improve the retention of Tc and/or I in Cast Stone, materials with a high affinity for Tc and/or I, termed "getters," can be added to decrease the rate of contaminant release and diffusivity, and improve Cast Stone performance. A series of kinetic batch sorption experiments was performed to determine the effectiveness of the getter materials. Several Tc getters [blast furnace slag, Sn (II) apatite, SnCl2, nanoporous Sn phosphate, KMS-2 (a potassium-metal-sulfide), and Sn(II) hydroxyapatite] and I getters [layered Bi hydroxide, natural argentite mineral, synthetic argentite, Ag-impregnated carbon, and Ag-exchanged zeolite] were tested in different solution media, 18.2 MΩ DI H2O and a caustic LAW waste simulant containing 6.5 M Na or 7.8 M Na. The experiments were conducted at room temperature in the presence or absence of air. Results indicated that most Tc getters (with the exception of KMS-2) performed better in the DI H2O solution than in the 6.5 and 7.8 M Na LAW simulant. In addition, Tc sequestration may be affected by the presence of other redox sensitive elements that were present in the LAW simulant, such as Cr. The Tc getter materials have been examined through various solid-state characterization techniques such as XRD, SEM/EDS, XANES and EXAFS which provided evidence for plausible mechanisms of aqueous Tc removal. The results indicated that the Tc precipitates differ depending on the getter material and that Tc(VII) is reduced to Tc(IV) in most of the getters but to a differing extents. For the I getters, Ag-exchanged zeolite and synthetic argentite were the most effective ones. The other I getters showed limited effectiveness for sorbing I under the high ionic strength and caustic conditions of

  18. Ice hydrometeor profile retrieval algorithm for high-frequency microwave radiometers: application to the CoSSIR instrument during TC4

    Science.gov (United States)

    Evans, K. F.; Wang, J. R.; O'C Starr, D.; Heymsfield, G.; Li, L.; Tian, L.; Lawson, R. P.; Heymsfield, A. J.; Bansemer, A.

    2012-09-01

    A Bayesian algorithm to retrieve profiles of cloud ice water content (IWC), ice particle size (Dme), and relative humidity from millimeter-wave/submillimeter-wave radiometers is presented. The first part of the algorithm prepares an a priori file with cumulative distribution functions (CDFs) and empirical orthogonal functions (EOFs) of profiles of temperature, relative humidity, three ice particle parameters (IWC, Dme, distribution width), and two liquid cloud parameters. The a priori CDFs and EOFs are derived from CloudSat radar reflectivity profiles and associated ECMWF temperature and relative humidity profiles combined with three cloud microphysical probability distributions obtained from in situ cloud probes. The second part of the algorithm uses the CDF/EOF file to perform a Bayesian retrieval with a hybrid technique that uses Monte Carlo integration (MCI) or, when too few MCI cases match the observations, uses optimization to maximize the posterior probability function. The very computationally intensive Markov chain Monte Carlo (MCMC) method also may be chosen as a solution method. The radiative transfer model assumes mixtures of several shapes of randomly oriented ice particles, and here random aggregates of spheres, dendrites, and hexagonal plates are used for tropical convection. A new physical model of stochastic dendritic snowflake aggregation is developed. The retrieval algorithm is applied to data from the Compact Scanning Submillimeter-wave Imaging Radiometer (CoSSIR) flown on the ER-2 aircraft during the Tropical Composition, Cloud and Climate Coupling (TC4) experiment in 2007. Example retrievals with error bars are shown for nadir profiles of IWC, Dme, and relative humidity, and nadir and conical scan swath retrievals of ice water path and average Dme. The ice cloud retrievals are evaluated by retrieving integrated 94 GHz backscattering from CoSSIR for comparison with the Cloud Radar System (CRS) flown on the same aircraft. The rms difference in

  19. Ice hydrometeor profile retrieval algorithm for high-frequency microwave radiometers: application to the CoSSIR instrument during TC4

    Directory of Open Access Journals (Sweden)

    K. F. Evans

    2012-09-01

    Full Text Available A Bayesian algorithm to retrieve profiles of cloud ice water content (IWC, ice particle size (Dme, and relative humidity from millimeter-wave/submillimeter-wave radiometers is presented. The first part of the algorithm prepares an a priori file with cumulative distribution functions (CDFs and empirical orthogonal functions (EOFs of profiles of temperature, relative humidity, three ice particle parameters (IWC, Dme, distribution width, and two liquid cloud parameters. The a priori CDFs and EOFs are derived from CloudSat radar reflectivity profiles and associated ECMWF temperature and relative humidity profiles combined with three cloud microphysical probability distributions obtained from in situ cloud probes. The second part of the algorithm uses the CDF/EOF file to perform a Bayesian retrieval with a hybrid technique that uses Monte Carlo integration (MCI or, when too few MCI cases match the observations, uses optimization to maximize the posterior probability function. The very computationally intensive Markov chain Monte Carlo (MCMC method also may be chosen as a solution method. The radiative transfer model assumes mixtures of several shapes of randomly oriented ice particles, and here random aggregates of spheres, dendrites, and hexagonal plates are used for tropical convection. A new physical model of stochastic dendritic snowflake aggregation is developed. The retrieval algorithm is applied to data from the Compact Scanning Submillimeter-wave Imaging Radiometer (CoSSIR flown on the ER-2 aircraft during the Tropical Composition, Cloud and Climate Coupling (TC4 experiment in 2007. Example retrievals with error bars are shown for nadir profiles of IWC, Dme, and relative humidity, and nadir and conical scan swath retrievals of ice water path and average Dme. The ice cloud retrievals are evaluated by retrieving integrated 94 GHz backscattering from CoSSIR for comparison

  20. What's in a Name?FRAMING:Martin-Bradshaw DYSfunctionality = Siegel ``Buzzwordism,Bandwagonism&Sloganeering For: Fun, Profit,Survival,Ego": From SOC to FLT Proof to High-Tc to Spintronics to Giant-Magnetoresistance: Ethics??? SHMETHICS!!! Rampant Sociolog

    Science.gov (United States)

    Siegel, Edward

    2008-03-01

    Buzzwordism,Bandwagonism,Sloganeering for:Fun,Profit,Survival, Ego=ethics DYSunctionality: Digits log-law: Siegel INVERSION: bosons=digits; Excluded d=0? P(0)=oo V P(1)high-Tc! Emery SC 3-band V Siegel multi-band Hubbard-mdls[J.Mag.Mag. Mtls.(1976-1980);APS March Mtgs.,1987-on];Intl.Conf.High-Tc:Stanford,1987;Berkeley,1987); WorldCong.SC, 1992]: 1970s<1993! Anderson SC RVB V Overhauser CORRECT SS/CDWs:1960s<1987. Fert-Grunberg GMR V decade-earlier Siegel[JMMM.7,31(1978);Mayo,Village Voice,p.40(8/21/78):1978<1988!!!A la Brian Martin-John Bradshaw addictions 12-step recovery programs[Healing SHAME That BINDS YOU]: One is only as SICK as one's SECRETS! Ethics? SHMETHICS! RAMPANT ethical DYSfunctionality!!!

  1. Application of Ionic Liquids for Tc Recovery from Aqueous Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, Dominique C.; Shkrob, Ilya A.; Vandegrift, George F. [Argonne National Laboratory, Chemical Sciences and Engineering Division, 9700 S. Cass Ave, Argonne, IL 60439 (United States); Wishart, James F. [Brookhaven National Laboratory (United States); Dietz, Mark L. [University of Wisconsin at Milwaukee (United States)

    2009-06-15

    Removal of technetium (Tc) from spent fuel waste is important because of its high mobility and long half-life. Current method of removal of Tc(VII) from the Tc product stream of the UREX process is a lengthy and complicated process which involves a multi-step chemical reduction of Tc from aqueous solution. Ionic liquids (ILs) have a potential to simplify separation and reduction of Tc from spent fuel streams. Studies of the extraction of actinides and fission products into ILs have demonstrated that these solvents can yield metal ion extraction efficiencies far exceeding those obtained in conventional liquid-liquid systems. Furthermore, ionic liquids are finding an increasing number of applications in electrodeposition of metals as their electrochemical window can reach more than 4 V and thus gives access to a number of elements that can not be electrodeposited from aqueous solutions. These finding suggest that ionic liquids can be used for separation of pertechnetate and subsequent electrodeposition on an electrode, to produce a metallic waste form. In this presentation we will present our progress on examining ionic liquids based extraction media for the separation of Tc(VII) from aqueous ammonia solutions. (authors)

  2. Toxicity of sup 99 Tc: Can it represent a risk to man

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, G.B.; Hegela, M.; Vankerkom, J.; Kirchmann, R.; Maisin, J.R.; Lambiet-Collier, M. (Centre d' Etude de l' Energie Nucleaire CEN-SCK (Belgium))

    1989-08-01

    The movement through the environment and the toxicity to plants of {sup 99}Tc have been studied. However, information is scanty on {sup 99}Tc toxicity to mammals even though this is the decisive criterion for assessing the consequences of releases of Tc. A critical tissue could be the thyroid because of its preferential accumulation of Tc and the developing organism because of its greater radiosensitivity; moreover, this toxicity might be enhanced under conditions of a low iodine (I) diet. These questions were studied in rats given large amounts of {sup 99}Tc in either a normal or an I-deficient diet for several months starting 2 wk before mating. Newborns were continued on these diets after weaning. The parameters determined were: occurrence of pregnancy and litter size, triiodothyronine and thyroxin in serum, uptake of {sup 131}I by the thyroid 24 h after injection, histology of the thyroid and concentration of Tc in tissues of the mothers and their decendants. Thyroid damage, as well as the effects on pregnancy, could be observed after amounts of 10 micrograms Tc g-1 food. Iodine deficiency only slightly influences the {sup 99}Tc toxicity. The chemical and radiological toxicity of {sup 99}Tc to rats is small. Consequently, it seems unlikely that contamination levels in the environment would ever reach levels that could lead to serious non-stochastic effects, even in the developing organism.

  3. Scintigraphic findings on {sup 99m}Tc-MDP, {sup 99m}Tc-sestamibi and {sup 99m}Tc-HMPAO images in Gaucher`s disease

    Energy Technology Data Exchange (ETDEWEB)

    Mariani, G. [Nuclear Medicine Service, DIMI, University of Genoa (Italy); Molea, N. [Regional Center of Nuclear Medicine, University of Pisa (Italy); La Civita, L. [Rheumatology Unit, University of Pisa (Italy); Porciello, G. [Rheumatology Unit, University of Pisa (Italy); Lazzeri, E. [Regional Center of Nuclear Medicine, University of Pisa (Italy); Ferri, C. [Rheumatology Unit, University of Pisa (Italy)

    1996-04-01

    We report here on the use of the lipophilic cationic complex technetium-99m sestamibi ({sup 99m}Tc-MIBI), employed as an indicator of increased cellular density and metabolic activity, to evaluate Gaucher cell infiltrates in the bone marrow; {sup 99m}Tc-hexametazime ({sup 99m}Tc-HMPAO) was also employed, as a pure indicator of lipidic infiltration in the bone marrow. A 67-year-old patient with known type 1 Gaucher`s disease presented with a painful left hip and knee and difficulty in gait subsequent to traumatic fracture of the left femoral neck that had required implant of a fixation screw-plaque. Bone scan with {sup 99m}Tc-methylene diphosphonate revealed reduced uptake at the distal metaphyseal-epiphyseal femoral region. In addition, whole-body maps and spot-view acquisitions of the thighs and legs were recorded at both 30 min and 2.5 h after the injection of {sup 99m}Tc-MIBI: the scintigraphic pattern clearly showed increased uptake at several sites involved by Gaucher deposits in the bone marrow (both knees, with variable intensity in different areas), matching the bone changes detected by conventional x-ray. The target to non-target ratios slowly decreased with time, from an average value of 2.25 in the early scan to an average value of 2 in the delayed scan. The lipid-soluble agent {sup 99m}Tc-HMPAO exhibited a superimposable scintigraphic pattern of accumulation at the involved sites, though with lower target to non-target ratios (1.27-1.48). The results obtained in this patient suggest a potential role of {sup 99m}Tc-MIBI in the scintigraphic evaluation of Gaucher`s lipid deposits in the bone marrow. If the results are confirmed in other patients, this radiopharmaceutical would offer clear advantages over {sup 133}Xe because of its wider availability and greater practicality (i.v. administration of {sup 99m}Tc-MIBI versus inhalation of {sup 133}Xe, and use of a single gamma camera instead of two as with {sup 133}Xe). (orig.). With 3 figs.

  4. The Distribution of Tc in Purex

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Tc is an important fission product (fission yield of 99Tc is 6.13%) and has complex chemical behavior. It distributes in many flows of Purex. The influence of Tc can be ignored in military plutonium production reactor because the burning up of it is very low and the production of Tc is little. The burning up of PWR is much deeper and the production of Tc is much higher than the former so the tendency and controlling of Tc in Purex causes popular consideration. The main reason for that is the peculiar chemical property of Tc. Tc co-extracts with Zr, U and Pu in 1A cell and effect the separation of U or Pu in 1B cell by consuming large amount of reductants and

  5. Power Systems Development Facility Gasification Test Campaign TC25

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2008-12-01

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC25, the second test campaign using a high moisture lignite coal from the Red Hills mine in Mississippi as the feedstock in the modified Transport Gasifier configuration. TC25 was conducted from July 4, 2008, through August 12, 2008. During TC25, the PSDF gasification process operated for 742 hours in air-blown gasification mode. Operation with the Mississippi lignite was significantly improved in TC25 compared to the previous test (TC22) with this fuel due to the addition of a fluid bed coal dryer. The new dryer was installed to dry coals with very high moisture contents for reliable coal feeding. The TC25 test campaign demonstrated steady operation with high carbon conversion and optimized performance of the coal handling and gasifier systems. Operation during TC25 provided the opportunity for further testing of instrumentation enhancements, hot gas filter materials, and advanced syngas cleanup technologies. The PSDF site was also made available for testing of the National Energy Technology Laboratory's fuel cell module and Media Process Technology's hydrogen selective membrane with syngas from the Transport Gasifier.

  6. Power Systems Development Facility Gasification Test Campaign TC25

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2008-12-01

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC25, the second test campaign using a high moisture lignite coal from the Red Hills mine in Mississippi as the feedstock in the modified Transport Gasifier configuration. TC25 was conducted from July 4, 2008, through August 12, 2008. During TC25, the PSDF gasification process operated for 742 hours in air-blown gasification mode. Operation with the Mississippi lignite was significantly improved in TC25 compared to the previous test (TC22) with this fuel due to the addition of a fluid bed coal dryer. The new dryer was installed to dry coals with very high moisture contents for reliable coal feeding. The TC25 test campaign demonstrated steady operation with high carbon conversion and optimized performance of the coal handling and gasifier systems. Operation during TC25 provided the opportunity for further testing of instrumentation enhancements, hot gas filter materials, and advanced syngas cleanup technologies. The PSDF site was also made available for testing of the National Energy Technology Laboratory's fuel cell module and Media Process Technology's hydrogen selective membrane with syngas from the Transport Gasifier.

  7. Calculated insulin resistance correlates with stone-forming urinary metabolic changes and greater stone burden in high-risk stone patients.

    Science.gov (United States)

    Tran, Timothy Y; Flynn, Mary; O'Bell, John; Pareek, Gyan

    2016-06-01

    Metabolic syndrome and diabetes are associated with nephrolithiasis. Proposed mechanisms of lithogenesis include insulin resistance causing low urine pH and hyperinsulinemia leading to hypercalciuria. Herein, we sought to determine whether insulin resistance was associated with differences in stone burden and lithogenic changes on 24-hour urine samples. All patients that underwent comprehensive metabolic workup including 24-hour urine samples and fasting insulin levels were included. Insulin resistance was defined as a homeostasis model assessment of insulin resistance value > 5 (HOMA-IR = (glucose×insulin)/405). Patients on active metabolic therapy were excluded or the 24-hour urine sample predating treatment was utilized for analysis. Stone burden was determined by totaling the maximal diameter of all stones noted on CT. 18 of 30 patients (60.0%) had HOMA-IR > 5. Among patients with calculated insulin resistance, stone burden was greater (17.6 mm vs. 6.3 mm, p = 0.002) and 24-hour urine samples revealed higher urine calcium (293 mg/d vs. 159 mg/d, p = 0.02) and lower urine pH and citrate (454 mg/d vs. 639 mg/d, p = 0.04 and 5.83 vs. 6.33, p = 0.04, respectively). Previous studies have demonstrated a correlation between metabolic syndrome, diabetes, and nephrolithiasis. This report demonstrates a quantitative increase in stone burden among patients with calculated insulin resistance. The pathway for this greater stone burden may be related to the urinary metabolic changes noted among patients with insulin resistance. In the future, targeting reduction of fasting insulin levels may represent a key element of stone disease prevention.

  8. Biological evaluation of 99mTc-labeled cyclic glycoprotein IIb/IIIa receptor antagonists in the canine arteriovenous shunt and deep vein thrombosis models: effects of chelators on biological properties of [99mTc]chelator-peptide conjugates.

    Science.gov (United States)

    Barrett, J A; Damphousse, D J; Heminway, S J; Liu, S; Edwards, D S; Looby, R J; Carroll, T R

    1996-01-01

    A series of 99mTc-labeled cyclic glycoprotein IIb/IIIa receptor antagonists, [99mTcO(L1-III)]-, [99mTcO-(L6-III)]-, [99mTcO(L1-V)]-, and [99mTcO(L6-V)]-, were evaluated in a canine arteriovenous (AV) shunt model for their potential use as thrombus imaging agents. The thrombus formed consists of a platelet-rich head and a fibrin-rich tail. All four agents were incorporated into the growing thrombus under both arterial (platelet-rich) and venous (platelet-poor) conditions. The rank order for uptake was [99mTcO(L1-V)]- > [99mTcO(L6-V)]- > [99mTcO(L6-III)]- > [99mTcO(L1-III)]- (arterial range, 5.8-0.47% id/g; venous range, 0.58-0.04% id/g). The uptakes of both [99mTcO(L6-III)]- and [99mTcO-(L1-III)]- under both arterial and venous conditions were not significantly greater than that of [99mTc]-albumin and [125I]fibrinogen. In contrast, the uptakes of both [99mTcO(L1-V)]- and [99mTcO(L6-V)]- were significantly greater than those of [99mTc]albumin and [125I]fibrinogen and comparable to that of [111In]platelets under both arterial and venous conditions. All four [99mTc]chelator-peptide conjugates are cleared faster than the controls with the clearance of the conjugates of peptide III faster than that of the conjugates of peptide V. The differences in incorporation are attributable to the effect of both the cyclic peptide and the chelator. The conjugate [99mTcO(L1-V)]- was also studied using a canine DVT (deep vein thrombosis) model. [99mTcO(L1-V)]- was actively incorporated into the growing thrombus with images clearly detectable within 15 min postinjection. At 2 h postinjection, thrombus/blood and thrombus/muscle ratios [region of interest (ROI)/background] were approximately 7/1 and 10/1, respectively. This clearly demonstrated that the conjugate [99mTcO(L1-V)]- has the potential for rapid diagnosis of thrombolic events occurring under both arterial and venous conditions.

  9. {sup 99m}Tc-HYNIC-derivatized ternary ligand complexes for {sup 99m}Tc-labeled polypeptides with low in vivo protein binding

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Masahiro; Arano, Yasushi E-mail: arano@p.chiba-u.ac.jp; Mukai, Takahiro; Fujioka, Yasushi; Ogawa, Kazuma; Uehara, Tomoya; Saga, Tsuneo; Konishi, Junji; Saji, Hideo

    2001-04-01

    6-Hydrazinopyridine-3-carboxylic acid (HYNIC) is a representative agent used to prepare technetium-99m ({sup 99m}Tc)-labeled polypeptides with tricine as a coligand. However, {sup 99m}Tc-HYNIC-labeled polypeptides show delayed elimination rates of the radioactivity not only from the blood but also from nontarget tissues such as the liver and kidney. In this study, a preformed chelate of tetrafluorophenol (TFP) active ester of [{sup 99m}Tc](HYNIC)(tricine)(benzoylpyridine: BP) ternary complex was synthesized to prepare {sup 99m}Tc-labeled polypeptides with higher stability against exchange reactions with proteins in plasma and lysosomes using the Fab fragment of a monoclonal antibody and galactosyl-neoglycoalbumin (NGA) as model polypeptides. When incubated in plasma, [{sup 99m}Tc](HYNIC-Fab)(tricine)(BP) showed significant reduction of the radioactivity in high molecular weight fractions compared with [{sup 99m}Tc](HYNIC-Fab)(tricine){sub 2.} When injected into mice, [{sup 99m}Tc](HYNIC-NGA)(tricine)(BP) was metabolized to [{sup 99m}Tc](HYNIC-lysine)(tricine)(BP) in the liver with no radioactivity detected in protein-bound fractions in contrast to the observations with [{sup 99m}Tc](HYNIC-NGA)(tricine){sub 2.} In addition, [{sup 99m}Tc](HYNIC-NGA)(tricine)(BP) showed significantly faster elimination rates of the radioactivity from the liver as compared with [{sup 99m}Tc](HYNIC-NGA)(tricine){sub 2.} Similar results were observed with {sup 99m}Tc-labeled Fab fragments where [{sup 99m}Tc](HYNIC-Fab)(tricine)(BP) exhibited significantly faster elimination rates of the radioactivity not only from the blood but also from the kidney. These findings indicated that conjugation of [{sup 99m}Tc](HYNIC)(tricine)(BP) ternary ligand complex to polypeptides accelerated elimination rates of the radioactivity from the blood and nontarget tissues due to low binding of the [{sup 99m}Tc](HYNIC)(tricine)(BP) complex with proteins in the blood and in the lysosomes. Such characteristics

  10. 优秀游泳运动员高强度训练中VAT和T/C值变化的分析研究%The Study on Change of VAT and T/C Ratio of Elite Swimmer in High Intensive Training

    Institute of Scientific and Technical Information of China (English)

    李越; 竺嵘; 张辉

    2001-01-01

    高强度训练周期中血清睾酮(T)与血清皮质醇(C)比值(T/C)和无氧阈速率(VAT)发生变化,其变化形式表现为:在训练周期中,T/C值和VAT发生变化的时间和程度不同;在训练周期中,男子游泳运动员与女子游泳运动员的T/C值和VAT变化的时间和程度不同。%The ratio of blood serum testosterone and cortisol (T/C) and VATchanges in high intensive training. The time and degree of the variation of T/C ratio and VAT are different. In training cycle, there is different between male swimmer and female swimmer in T/C ratio and VAT.

  11. SYNTHESIS, REACTIONS AND STRUCTURE OF CP'TC(CO)3 DERIVATIVES

    NARCIS (Netherlands)

    CASTRO, HHK; MEETSMA, A; TEUBEN, JH; VAALBURG, W; PANEK, K

    1991-01-01

    A novel procedure for a high yield synthesis of Tc2(CO)10 is reported. Cyclopentadienyl technetium carbonyl complexes of general formula Cp'Tc(CO)3, where Cp' = eta-5-C5H5, eta-5-C5Me5, or eta-5-C5(Me)4[(CH2)3NMe2], have been prepared by reaction of Tc(CO)5I with the appropriate lithium cyclopentadi

  12. Synthesis, reactions and structure of Cp´Tc(CO)3 derivatives

    NARCIS (Netherlands)

    Knight Castro, H.H.; Meetsma, A.; Teuben, J.H.; Vaalburg, W.; Panek, K.

    1991-01-01

    A novel procedure for a high yield synthesis of Tc2(CO)10 is reported. Cyclopentadienyl technetium carbonyl complexes of general formula Cp´Tc(CO)3, where Cp´ = η5-C5H5, η5-C5Me5, or η5-C5(Me)4[(CH2)3NMe2], have been prepared by reaction of Tc(CO)5I with the appropriate lithium cyclopentadienide in

  13. First results of dose to patient in CT extracted with an automatic registration system; Primeros resultados de dosis a paciente en TC extraidas con un sistema automatico de registro

    Energy Technology Data Exchange (ETDEWEB)

    Minambres Moro, A.; Fernandez Leton, P.; Garcia Ruiz-Zorilla, J.; Perez Moreno, J. M.; Zucca Aparicio, D.

    2013-07-01

    Radiation protection of the patient in computed tomography (CT) is a priority for several reasons: the dose received during a scan is relatively high, is the diagnostic mode with greater contribution to dose to patient collective and the frequency of completion of TC is increasing rapidly the past few years. On the other hand, are currently beginning to commercially offer automated registration of dose to patient receiving dosimetric parameters of all scans performed on the equipment connected to the system. In this communication the first results are presented from two TC connected to an automatic system of this kind recently installed at our Center. (Author)

  14. Online Course Use in New York High Schools: Results from a Survey in the Greater Capital Region. REL 2015-074. Stated Briefly

    Science.gov (United States)

    Clements, Margaret; Pazzaglia, Angela M.; Zweig, Jacqueline

    2015-01-01

    This "Stated Briefly" report is a companion piece that summarizes the results of another report of the same name. The goal of the study conducted by the Regional Educational Laboratory Northeast and Islands' Northeast Rural Districts Research Alliance (NRDRA) was to provide information about how and why high schools in the Greater…

  15. Genomewide high-density SNP linkage analysis of non-BRCA1/2 breast cancer families identifies various candidate regions and has greater power than microsatellite studies

    NARCIS (Netherlands)

    A. González-Neira (Anna); J.M. Rosa-Rosa; A. Osorio (Ana); E. Gonzalez (Emilio); M.C. Southey (Melissa); O. Sinilnikova (Olga); H. Lynch (Henry); R.A. Oldenburg (Rogier); C.J. van Asperen (Christi); N. Hoogerbrugge (Nicoline); G. Pita (G.); P. Devilee (Peter); D. Goldgar (David); J. Benítez (Javier)

    2007-01-01

    textabstractBackground: The recent development of new high-throughput technologies for SNP genotyping has opened the possibility of taking a genome-wide linkage approach to the search for new candidate genes involved in heredity diseases. The two major breast cancer susceptibility genes BRCA1 and BR

  16. High T$_{c}$ superconductors and related transition metal oxides special contributions in honor of K. Alex Müller on the occasion of his 80th birthday

    CERN Document Server

    Bussmann-Holder, Annette

    2007-01-01

    This book containing 30 articles written by highly reputed experts is dedicated to K. Alex Müller on the occasion of his 80th birthday. The contributions reflect the major research areas of K. Alex Müller which he activated in high temperature superconductivity and phase transitions. They are theoretical as well as experimental ones and focus mainly on high temperature superconductivity. A smaller part deals with ferroelectricity and their applications. Also in this field there have recently been major break throughs experimentally as well as theoretically which will be addressed by the invited authors. During the scientific career of K. Alex Müller he made major advances in the understanding of ferroelectricity, which used to be his major research field. The discovery of superconductivity in cuprates for which he received together with J. Georg Bednorz the Nobel Prize in 1987 has not diminished his interest in this area, but has enlarged his activities considerably.

  17. A conveniently prepared Tc-99m resin for semisolid gastric emptying studies

    Energy Technology Data Exchange (ETDEWEB)

    Wirth, N.; Swanson, D.; Shapiro, B.; Nakajo, M.; Coffey, J.L.; Eckhauser, F.; Owyang, C.

    1983-06-01

    A polystyrene resin, suitable for semi-solid gastric emptying studies, was rapidly (less than 20 min) and conveniently prepared using commercially available reagents. Using the outlined procedure, Chelex-100 resin bound Tc-99m with greater than 98% labeling efficiency. The resulting Tc-99m Chelex-100 resin demonstrated excellent in vitro and in vivo stability. The clinical application of Tc-99m Chelex-100 resin, mixed with oatmeal, was tested in normal subjects and in various patient groups, including diabetic autonomic neuropathy, pyloric obstruction, postoperative dumping syndrome, and morbidly obese patients before and after gastroplasty.

  18. Conveniently prepared Tc-99m resin for semisolid gastric emptying studies

    Energy Technology Data Exchange (ETDEWEB)

    Wirth, N. (Univ. of Michigan, Ann Arbor); Shapiro, B.; Nakajo, M.; Coffey, J.L.; Eckhauser, F.; Owyang, C.

    1983-06-01

    A polystyrene resin, suitable for semi-solid gastric emptying studies, was rapidly (<20 min) and coveniently prepared using commercially available reagents. Using the outlined procedure, Chelex-100 resin bound Tc-99m with greater than 98% labeling efficiency. The resulting Tc-99m Chelex-100 resin demonstrated excellent in vitro and in vivo stability. The clinical application of Tc-99m Chelex-100 resin, mixed with oatmeal, was tested in normal subjects and in various patient groups, including diabetic autonomic neuropathy, pyloric obstruction, postoperative dumping syndrome, and morbidly obese patients before and after gastroplasty.

  19. Role of the upper branch of the hour-glass magnetic spectrum in the formation of the main kink in the electronic dispersion of high-Tc cuprate superconductors

    Science.gov (United States)

    Geffroy, Dominique; Chaloupka, Jiří; Dahm, Thomas; Munzar, Dominik

    2016-04-01

    We investigate the electronic dispersion of the high-Tc cuprate superconductors using the fully self-consistent version of the phenomenological model, where charge planar quasiparticles are coupled to spin fluctuations. The inputs we use, the underlying (bare) band structure and the spin susceptibility χ , are extracted from fits of angle-resolved photoemission and inelastic neutron scattering data of underdoped YBa2Cu3O6.6 by T. Dahm and coworkers [Nat. Phys. 5, 217 (2009), 10.1038/nphys1180]. Our main results are as follows: (i) We have confirmed the finding by Dahm and coworkers that the main nodal kink is, for the present values of the input parameters, determined by the upper branch of the hourglass of χ . We demonstrate that the properties of the kink depend qualitatively on the strength of the charge-spin coupling. (ii) The effect of the resonance mode of χ on the electronic dispersion strongly depends on its kurtosis in the quasimomentum space. A low (high) kurtosis implies a negligible (considerable) effect of the mode on the dispersion in the near-nodal region. (iii) The energy of the kink decreases as a function of the angle θ between the Fermi surface cut and the nodal direction, in qualitative agreement with recent experimental observations. We clarify the trend and make a specific prediction concerning the angular dependence of the kink energy in underdoped YBa2Cu3O6.6 .

  20. Novel (99m)Tc(III)-azide complexes [(99m)Tc(N3)(CDO)(CDOH)2B-R] (CDOH2=cyclohexanedione dioxime) as potential radiotracers for heart imaging.

    Science.gov (United States)

    Liu, Min; Zheng, Yumin; Avcibasi, Ugur; Liu, Shuang

    2016-11-01

    In this study, novel (99m)Tc(III)-azide complexes [(99m)Tc(N3)(CDO)(CDOH)2B-R] ((99m)Tc-ISboroxime-N3: R=IS; (99m)Tc-MPboroxime-N3: R=MP; (99m)Tc-PAboroxime-N3: R=PA; (99m)Tc-PYboroxime-N3: R=PY; and (99m)Tc-Uboroxime-N3: R=5U) were evaluated as heart imaging agents. Complexes [(99m)Tc(N3)(CDO)(CDOH)2B-R] (R=IS, MP, PA, PY and 5U) were prepared by ligand exchange between NaN3 and [(99m)TcCl(CDO)(CDOH)2B-R]. Biodistribution and imaging studies were carried out in Sprague-Dawley rats. Image quantification was performed to compare their initial heart uptake and myocardial retention. (99m)Tc-ISboroxime-N3, (99m)Tc-PYboroxime-N3 and (99m)Tc-Uboroxime-N3 were prepared with high RCP (93-98%) while the RCP of (99m)Tc-MPboroxime-N3 and (99m)Tc-PAboroxime-N3 was 80-85%. The myocardial retention curves of (99m)Tc-ISboroxime-N3, (99m)Tc-PYboroxime-N3 and (99m)Tc-Uboroxime-N3 were best fitted to the bi-exponential decay function. The half-time of the fast component was 1.6±0.4min for (99m)Tc-ISboroxime-N3, 0.7±0.1min for (99m)Tc-PYboroxime-N3 and 0.9±0.4min for (99m)Tc-Uboroxime-N3. The 2-min heart uptake from biodistribution studies followed the ranking order of (99m)Tc-ISboroxime-N3 (3.60±0.68%ID/g)>(99m)Tc-PYboroxime-N3 (2.35±0.37%ID/g)≫(99m)Tc-Uboroxime-N3 (1.29±0.06%ID/g). (99m)Tc-ISboroxime-N3 had the highest 2-min heart uptake among (99m)Tc radiotracers revaluated in SD rats. High quality SPECT images were obtained with the right and left ventricular walls being clearly delineated. The best image acquisition window was 0-5min for (99m)Tc-ISboroxime-N3. Both azide coligand and boronate caps had significant impact on the heart uptake and myocardial retention of complexes [(99m)Tc(N3)(CDO)(CDOH)2B-R]. Among the radiotracers evaluated in SD rats, (99m)Tc-ISboroxime-N3 has the highest initial heart uptake with the heart retention comparable to that of (99m)Tc-Teboroxime. (99m)Tc-ISboroxime-N3 is a promising alternative to (99m)Tc-Teboroxime for SPECT MPI. Copyright

  1. Greater effects of high- compared with moderate-intensity interval training on cardio-metabolic variables, blood leptin concentration and ratings of perceived exertion in obese adolescent females.

    Science.gov (United States)

    Racil, G; Coquart, J B; Elmontassar, W; Haddad, M; Goebel, R; Chaouachi, A; Amri, M; Chamari, K

    2016-06-01

    This study examined the effects of high- vs. moderate-intensity interval training on cardiovascular fitness, leptin levels and ratings of perceived exertion (RPE) in obese female adolescents. Forty-seven participants were randomly assigned to one of three groups receiving either a 1:1 ratio of 15 s of effort comprising moderate-intensity interval training (MIIT at 80% maximal aerobic speed: MAS) or high-intensity interval training (HIIT at 100% MAS), with matched 15 s recovery at 50% MAS, thrice weekly, or a no-training control group. The HIIT and MIIT groups showed improved (p HIIT group showed decreased waist circumference (WC) (p = 0.017). The effect of exercise on maximal oxygen uptake (VO2max) was significant (p = 0.019, ES = 0.48 and p = 0.010, ES = 0.57, HIIT and MIIT, respectively). The decrease of rate-pressure product (RPP) (p HIIT and MIIT, respectively) followed the positive changes in resting heart rate and blood pressures. Blood glucose, insulin level and the homeostasis model assessment index for insulin decreased (p HIIT and MIIT, respectively. In the post-intervention period, blood leptin was strongly associated with %BF (p HIIT and MIIT groups, respectively, while RPE was strongly associated with BM (p HIIT group. The results suggest that high-intensity interval training may produce more positive effects on health determinants in comparison with the same training mode at a moderate intensity.

  2. High Cellular Monocyte Activation in People Living With Human Immunodeficiency Virus on Combination Antiretroviral Therapy and Lifestyle-Matched Controls Is Associated With Greater Inflammation in Cerebrospinal Fluid

    Science.gov (United States)

    Booiman, Thijs; Wit, Ferdinand W.; Maurer, Irma; De Francesco, Davide; Sabin, Caroline A.; Harskamp, Agnes M.; Prins, Maria; Garagnani, Paolo; Pirazzini, Chiara; Franceschi, Claudio; Fuchs, Dietmar; Gisslén, Magnus; Winston, Alan; Reiss, Peter; Reiss, P.; Wit, F. W. N. M.; Schouten, J.; Kooij, K. W.; van Zoest, R. A.; Elsenga, B. C.; Janssen, F. R.; Heidenrijk, M.; Zikkenheiner, W.; van der Valk, M.; Kootstra, N. A.; Booiman, T.; Harskamp-Holwerda, A. M.; Boeser-Nunnink, B.; Maurer, I.; Mangas Ruiz, M. M.; Girigorie, A. F.; Villaudy, J.; Frankin, E.; Pasternak, A.; Berkhout, B.; van der Kuyl, T.; Portegies, P.; Schmand, B. A.; Geurtsen, G. J.; ter Stege, J. A.; Klein Twennaar, M.; Majoie, C. B. L. M.; Caan, M. W. A.; Su, T.; Weijer, K.; Bisschop, P. H. L. T.; Kalsbeek, A.; Wezel, M.; Visser, I.; Ruhé, H. G.; Franceschi, C.; Garagnani, P.; Pirazzini, C.; Capri, M.; Dall’Olio, F.; Chiricolo, M.; Salvioli, S.; Hoeijmakers, J.; Pothof, J.; Prins, M.; Martens, M.; Moll, S.; Berkel, J.; Totté, M.; Kovalev, S.; Gisslén, M.; Fuchs, D.; Zetterberg, H.; Winston, A.; Underwood, J.; McDonald, L.; Stott, M.; Legg, K.; Lovell, A.; Erlwein, O.; Doyle, N.; Kingsley, C.; Sharp, D. J.; Leech, R.; Cole, J. H.; Zaheri, S.; Hillebregt, M. M. J.; Ruijs, Y. M. C.; Benschop, D. P.; Burger, D.; de Graaff-Teulen, M.; Guaraldi, G.; Bürkle, A.; Sindlinger, T.; Moreno-Villanueva, M.; Keller, A.; Sabin, C.; de Francesco, D.; Libert, C.; Dewaele, S.

    2017-01-01

    Abstract Background. Increased monocyte activation and intestinal damage have been shown to be predictive for the increased morbidity and mortality observed in treated people living with human immunodeficiency virus (PLHIV). Methods. A cross-sectional analysis of cellular and soluble markers of monocyte activation, coagulation, intestinal damage, and inflammation in plasma and cerebrospinal fluid (CSF) of PLHIV with suppressed plasma viremia on combination antiretroviral therapy and age and demographically comparable HIV-negative individuals participating in the Comorbidity in Relation to AIDS (COBRA) cohort and, where appropriate, age-matched blood bank donors (BBD). Results. People living with HIV, HIV-negative individuals, and BBD had comparable percentages of classical, intermediate, and nonclassical monocytes. Expression of CD163, CD32, CD64, HLA-DR, CD38, CD40, CD86, CD91, CD11c, and CX3CR1 on monocytes did not differ between PLHIV and HIV-negative individuals, but it differed significantly from BBD. Principal component analysis revealed that 57.5% of PLHIV and 62.5% of HIV-negative individuals had a high monocyte activation profile compared with 2.9% of BBD. Cellular monocyte activation in the COBRA cohort was strongly associated with soluble markers of monocyte activation and inflammation in the CSF. Conclusions. People living with HIV and HIV-negative COBRA participants had high levels of cellular monocyte activation compared with age-matched BBD. High monocyte activation was predictive for inflammation in the CSF. PMID:28680905

  3. Less-healthy eating behaviors have a greater association with a high level of sugar-sweetened beverage consumption among rural adults than among urban adults

    Directory of Open Access Journals (Sweden)

    Wesley R. Dean

    2011-04-01

    Full Text Available Background: Sugar-sweetened beverage (SSB consumption is associated with the increasing prevalence of overweight and obesity in the United States; however, little is known about how less-healthy eating behaviors influence high levels of SSB consumption among rural adults. Objective: We assessed the frequency of SSB consumption among rural and urban adults, examined the correlates of frequent SSB consumption, and determined difference in correlates between rural and urban adults in a large region of Texas. Design: A cross-sectional study using data on 1,878 adult participants (urban = 734 and rural = 1,144, who were recruited by random digit dialing to participate in the seven-county 2006 Brazos Valley Community Health Assessment. Data included demographic characteristics, eating behaviors (SSB consumption, frequency of fast-food meals, frequency of breakfast meals, and daily fruit and vegetable intake, and household food insecurity. Results: The prevalence of any consumption of SSB and the prevalence of high consumption of SSB were significantly higher among rural adults compared with urban counterparts. The multivariable logistic regression models indicated that a high level of SSB consumption (≥3 cans or glasses SSB/day was associated with demographic characteristics (poverty-level income and children in the home, frequent consumption of fast-food meals, infrequent breakfast meals, low fruit and vegetable intake, and household food insecurity especially among rural adults. Conclusions: This study provides impetus for understanding associations among multiple eating behaviors, especially among economically and geographically disadvantaged adults. New strategies are needed for educating consumers, not only about how to moderate their SSB intake, but also how to simultaneously disrupt the co-occurrence of undesirable eating and promote healthful eating.

  4. 高温压电材料的概况及发展趋势%Development of high Tc piezoelectric ceramics

    Institute of Scientific and Technical Information of China (English)

    石维; 冉耀宗; 左江红; 王强; 陶涛; 欧永康

    2011-01-01

    介绍了高温压电材料的研究现状,综述了钙钛矿、钨青铜型、铋层状、碱金属铌酸盐结构体系4种不同压电陶瓷的结构及研究情况,并指出了高居里点压电陶瓷的研究方向和发展趋势。%This paper reviewed the high Curie temperature piezoelectric materials, including tungsten bronze, bismuth layer structured, Perovskite types piezoelectric ceramics and corundum structure ceramics. The research studies on the development of four different structure types high curies piezoelectric ceramics were also reviewed. In addition, the research direction and piezoelectric ceramic development trend were discussed.

  5. System applications of high-Tc superconductor sampler cooled y a cryo-cooler; Reitoki reikyaku koon chodendo sanpura no shisutemu oyo

    Energy Technology Data Exchange (ETDEWEB)

    Hidaka, M.; Sato, T.; Tahara, S. [NEC Corp., Tokyo (Japan). Fundamental Research Laboratories

    1999-11-10

    It is possible to require these currents from the voltage measurement using the semiconductor sampler, if the impedance is known. However, the measurement was not possible for the current in LSI with the complicated layer structure, since the impedance is generally unknown. We develop 'the current measurement system' using characteristics of the high-temperature superconductivity sampler in order to solve this. In this system, the sampler chip is cooled to near 40K using the refrigerating machine. (NEDO)

  6. Genomewide high-density SNP linkage analysis of non-BRCA1/2 breast cancer families identifies various candidate regions and has greater power than microsatellite studies

    Directory of Open Access Journals (Sweden)

    Gonzalez-Neira Anna

    2007-08-01

    Full Text Available Abstract Background The recent development of new high-throughput technologies for SNP genotyping has opened the possibility of taking a genome-wide linkage approach to the search for new candidate genes involved in heredity diseases. The two major breast cancer susceptibility genes BRCA1 and BRCA2 are involved in 30% of hereditary breast cancer cases, but the discovery of additional breast cancer predisposition genes for the non-BRCA1/2 breast cancer families has so far been unsuccessful. Results In order to evaluate the power improvement provided by using SNP markers in a real situation, we have performed a whole genome screen of 19 non-BRCA1/2 breast cancer families using 4720 genomewide SNPs with Illumina technology (Illumina's Linkage III Panel, with an average distance of 615 Kb/SNP. We identified six regions on chromosomes 2, 3, 4, 7, 11 and 14 as candidates to contain genes involved in breast cancer susceptibility, and additional fine mapping genotyping using microsatellite markers around linkage peaks confirmed five of them, excluding the region on chromosome 3. These results were consistent in analyses that excluded SNPs in high linkage disequilibrium. The results were compared with those obtained previously using a 10 cM microsatellite scan (STR-GWS and we found lower or not significant linkage signals with STR-GWS data compared to SNP data in all cases. Conclusion Our results show the power increase that SNPs can supply in linkage studies.

  7. Gamma/neutron analysis for SNM signatures at high-data rates(greater than 107 cps) for single-pulse active interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Forman L.; Dioszegi, I.; Salwen, C.

    2011-04-26

    We are developing a high data gamma/neutron spectrometer suitable for active interrogation of special nuclear materials (SNM) activated by a single burst from an intense source. We have tested the system at Naval Research Laboratory's (NRL) Mercury pulsed-power facility at distances approaching 10 meters from a depleted uranium (DU) target. We have found that the gamma-ray field in the target room 'disappears' 10 milliseconds after the x-ray flash, and that gamma ray spectroscopy will then be dominated by isomeric states/beta decay of fission products. When a polyethylene moderator is added to the DU target, a time-dependent signature of the DU is produced by thermalized neutrons. We observe this signature in gamma-spectra measured consecutively in the 0.1-1.0 ms time range. These spectra contain the Compton edge line (2.2 MeV) from capture in hydrogen, and a continuous high energy gamma-spectrum from capture or fission in minority constituents of the DU.

  8. Long-term community changes on a high-latitude coral reef in the Greater St Lucia Wetland Park, South Africa.

    Science.gov (United States)

    Schleyer, Michael H; Kruger, Alke; Celliers, Louis

    2008-03-01

    South African coral reefs are limited in size but, being marginal, provide a model for the study of many of the stresses to which these valuable systems are being subjected globally. Soft coral cover, comprising relatively few species, exceeds that of scleractinians over much of the reefs. The coral communities nevertheless attain a high biodiversity at this latitude on the East African coast. A long-term monitoring programme was initiated in 1993, entailing temperature logging and image analysis of high resolution photographs of fixed quadrats on representative reef. Sea temperatures rose by 0.15 degrees C p.a. at the site up to 2000 but have subsequently been decreasing by 0.07 degrees C p.a. Insignificant bleaching was encountered in the region during the 1998 El Nino Southern Oscillation (ENSO) event, unlike elsewhere in East Africa, but quantifiable bleaching occurred during an extended period of warming in 2000. Peak temperatures on the South African reefs thus appear to have attained the coral bleaching threshold. While this has resulted in relatively little bleaching thus far, the increased temperatures appear to have had a deleterious effect on coral recruitment success as other anthropogenic influences on the reefs are minimal. Recruitment success diminished remarkably up to 2004 but appears again to be improving. Throughout, the corals have also manifested changes in community structure, involving an increase in hard coral cover and reduction in that of soft corals, resulting in a 5.5% drop in overall coral cover. These "silent" effects of temperature increase do not appear to have been reported elsewhere in the literature.

  9. Israeli 'cancer shift' over heart disease mortality may be led by greater risk in women with high intake of n-6 fatty acids.

    Science.gov (United States)

    Shapira, Niva

    2007-10-01

    My hypothesis is that higher female sensitivity to increased n-6 polyunsaturated fatty acids and their carcinogenic effect may contribute to the recent Israeli 'cancer shift' over heart disease mortality (23.1 vs. 22.3%, 1999). High n-6 polyunsaturated fatty acid intake was the presumed dietary risk underlying the 'Israeli paradox', the unexpected gap between 'ill' health and 'good' diet. Scientific literature and population health surveillance reports were reviewed. Cancer death rates for Israeli Arabs, who consumed a more traditional Mediterranean diet - more monounsaturated fatty acids, mostly olive oil, and less n-6 polyunsaturated fatty acids - are still 1.1-1.7 times (men-women) lower than in Israeli Jews, but are increasing faster (23.6 and 5.1% vs. 5.3 and -3.3%, 1980-2000), concurrently with dietary 'Israelization' - specifically, increased intake of n-6 polyunsaturated fatty acids. Israeli-Jewish women attained an earlier, much larger (29 vs. 7%, 1999) 'cancer : heart disease mortality shift' (ratio >1.0), ranked much worse for cancer (15th/44 European countries) than men (37th) and heart disease (38th and 34th, respectively), and had much higher cancer prevalence (1 : 3) than Israeli-Arab women (1 : 6), though dietary compositions were similar, save for higher n-6 polyunsaturated fatty acid and polyunsaturated fatty acid : monounsaturated fatty acid ratio. Population studies of Israeli Jews, Arabs, and women support the association of high n-6 polyunsaturated fatty acid intake with increased cancer risk and higher female sensitivity. Research findings suggest that gender and sex hormones may influence n-6 polyunsaturated fatty acid metabolism and carcinogenesis. This appears to be the first time gender has been proposed to modulate national cancer epidemiology, suggesting implications for differential nutritional prevention, warranting further research.

  10. High Tc ferrimagnetic organic-inorganic hybrid materials with MnII-L-MnII and MnII-NC-NbIV linkages (L=pyrazine, pyrazine-N,N'-dioxide, bipyrimidine).

    Science.gov (United States)

    Podgajny, Robert; Pinkowicz, Dawid; Korzeniak, Tomasz; Nitek, Wojciech; Rams, Michał; Sieklucka, Barbara

    2007-11-26

    A series of heterobimetallic, cyano-bridged 3D inorganic-organic hybrid networks with MnII-L-MnII and MnII-NC-NbIV linkages are reported. Reaction of [Mn(H2O)6]2+ with [Nb(CN)8]4- in the presence of organic linker L (pyrazine (pyz), pyrazine-N,N'-dioxide (pzdo), and 2,2'-bipyrimidine (bpym)) in H2O affords {MnII2(pz)2(H2O)4[NbIV(CN)8]}.pz.3H2O (1), {MnII2(pzdo)(H2O)4[NbIV(CN)8]}.5H2O (2), and {MnII2(bpym)(H2O)2[NbIV(CN)8]} (3), respectively. 1-3 were examined by X-ray crystallography and vibrational and magnetochemical studies. 1 is characterized by the coexistence of 3D inorganic cyano-bridged and 1D organic [Mn-(micro-pyz)]n2n+ sublattices along with the presence of monocoordinated and crystallization molecules of pyrazine. Assemblies 2 and 3 exhibit dimeric {MnII2-(micro-L)}4+ coordination motifs. The magnetic behavior of heterobimetallic 1-3 complexes is dominated by antiferromagnetic coupling between MnII and NbIV centers mediated by cyano bridges, resulting in long-range ferrimagnetic ordering with a high TC of 27 (1), 37 (2), and 50 K (3). The magneto-structural correlation leads to the conclusion that the magnitude of TC is related to the type of coordination polyhedra of [Nb(CN)8] moieties (SAPR (1), intermediate between SAPR and DD (2), and DD (3)), the relative number of cyano bridges per Mn2Nb unit, and coexistence of inorganic and organic connectivity. FC/ZFC responses appear to be sensitive to the degree of organic connectivity. The discussion of magneto-structural correlation is based on the spin-density properties of adequate heterobimetallic systems containing octacyanometalates.

  11. High-Tc ferromagnetic semiconductor-like behavior and unusual electrical properties in compounds with a 2×2×2 superstructure of the half-Heusler phase.

    Science.gov (United States)

    Xiong, Ding-Bang; Okamoto, Norihiko L; Waki, Takeshi; Zhao, Yufeng; Kishida, Kyosuke; Inui, Haruyuki

    2012-02-27

    Heusler phases, including the full- and half-Heusler families, represent an outstanding class of multifunctional materials on account of their great tunability in compositions, valence electron counts (VEC), and properties. Here we demonstrate a systematic design of a series of new compounds with a 2×2×2 superstructure of the half-Heusler unit cell in X-Y-Z (X=Fe, Ru, Co, Rh, Ir; Y=Zn, Mn; Z=Sn, Sb) systems. Their structures were solved by using both powder and single-crystal X-ray diffraction, and also directly observed by using high-angle annular dark-field imaging in a scanning transmission electron microscope (HAADF-STEM). The VEC values of these new compounds span a wide and continuous range comparable to those for the full- and half-Heusler families, thereby implying tunability in compositions and physical properties in the superstructure. In fact, we observed abnormal electrical properties and a ferromagnetic semiconductor-like behavior with a high and tunable Curie temperature in these superstructures. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Topological susceptibility near Tc in SU(3 gauge theory

    Directory of Open Access Journals (Sweden)

    Guang-Yi Xiong

    2016-01-01

    Full Text Available Topological charge susceptibility χt for pure gauge SU(3 theory at finite temperature is studied using anisotropic lattices. The over-improved stout-link smoothing method is utilized to calculate the topological charge. Near the phase transition point we find a rapid declining behavior for χt with values decreasing from (188(1 MeV4 to (67(3 MeV4 as the temperature increased from zero temperature to 1.9Tc which demonstrates the existence of topological excitations far above Tc. The 4th order cumulant c4 of topological charge, as well as the ratio c4/χt is also investigated. Results of c4 show step-like behavior near Tc while the ratio at high temperature agrees with the value as predicted by the diluted instanton gas model.

  13. Microstructure and Properties of Laser Additive Manufacturing TC Bearing

    OpenAIRE

    YANG Jiao-xi; Hu, Xing; WANG Yan-fang

    2016-01-01

    In order to solve the problem of uneven wear of TC bearing that conventional method brought and improve its service life,wear-resistant coating was fabricated on the surface of steel parts matrix with the method of laser additive manufacture. The Cr3C2/Fe based alloy was deposited by laser cladding technique on the inner-sleeve cylindrical and outer-sleeve bore of TC bearing with two different process parameters. The high-performance coating was obtained respectively, of cracks free,no pores ...

  14. High chance that current atmospheric greenhouse concentrations commit to warmings greater than 1.5 °C over land.

    Science.gov (United States)

    Huntingford, Chris; Mercado, Lina M

    2016-07-27

    The recent Paris UNFCCC climate meeting discussed the possibility of limiting global warming to 2 °C since pre-industrial times, or possibly even 1.5 °C, which would require major future emissions reductions. However, even if climate is stabilised at current atmospheric greenhouse gas (GHG) concentrations, those warming targets would almost certainly be surpassed in the context of mean temperature increases over land only. The reason for this is two-fold. First, current transient warming lags significantly below equilibrium or "committed" warming. Second, almost all climate models indicate warming rates over land are much higher than those for the oceans. We demonstrate this potential for high eventual temperatures over land, even for contemporary GHG levels, using a large set of climate models and for which climate sensitivities are known. Such additional land warming has implications for impacts on terrestrial ecosystems and human well-being. This suggests that even if massive and near-immediate emissions reductions occur such that atmospheric GHGs increase further by only small amounts, careful planning is needed by society to prepare for higher land temperatures in an eventual equilibrium climatic state.

  15. High chance that current atmospheric greenhouse concentrations commit to warmings greater than 1.5 °C over land

    Science.gov (United States)

    Huntingford, Chris; Mercado, Lina M.

    2016-07-01

    The recent Paris UNFCCC climate meeting discussed the possibility of limiting global warming to 2 °C since pre-industrial times, or possibly even 1.5 °C, which would require major future emissions reductions. However, even if climate is stabilised at current atmospheric greenhouse gas (GHG) concentrations, those warming targets would almost certainly be surpassed in the context of mean temperature increases over land only. The reason for this is two-fold. First, current transient warming lags significantly below equilibrium or “committed” warming. Second, almost all climate models indicate warming rates over land are much higher than those for the oceans. We demonstrate this potential for high eventual temperatures over land, even for contemporary GHG levels, using a large set of climate models and for which climate sensitivities are known. Such additional land warming has implications for impacts on terrestrial ecosystems and human well-being. This suggests that even if massive and near-immediate emissions reductions occur such that atmospheric GHGs increase further by only small amounts, careful planning is needed by society to prepare for higher land temperatures in an eventual equilibrium climatic state.

  16. Repeated magnetization with temperature control in a high-Tc superconducting bulk; Ondo seigyo wo tomonatta koon chodendo baaruku tai no dotai no kurikaeshi no chakuji ho

    Energy Technology Data Exchange (ETDEWEB)

    Kamijo, H.; Fujimoto, H. [Railway tech. Research Inst., Tokyo (Japan)

    2000-05-29

    It examines applicability of the hulk magnet which uses magnetize-ingly the high-temperature superconductivity bulk body to the superconducting magnet for levitation system railway. It must be magnetized to the superconductive bulk body in respect of as much as possible large magnetic flux in order to obtain the powerful bulk magnet. Therefore, large coil for the impression magnetic field and power are required, and there is a problem of the growth of large electromagnetic mosquito even in the magnetizing process. Then, it is trying the method for magnetizing large magnetic field to the superconductive bulk body by comparatively small impression magnetic field by the method for repeatedly carrying out field cool and pulse magnetizing, while it gradually lowers the temperature of the superconductive bulk body from the critical temperature. (NEDO)

  17. Simulating the Euclidean time Schroedinger equations using an Intel iPSC/860 hypercube: Application to the t-J model of high-{Tc} superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Kovarik, M.D.; Barnes, T. [Oak Ridge National Lab., TN (United States)]|[Tennessee Univ., Knoxville, TN (United States). Dept. of Physics

    1993-10-01

    We describe a Monte Carlo simulation of a dynamical fermion problem in two spatial dimensions on an Intel iPSC/860 hypercube. The problem studied is the determination of the dispersion relation of a dynamical hole in the t-J model of the high temperature superconductors. Since this problem involves the motion of many fermions in more than one spatial dimensions, it is representative of the class of systems that suffer from the ``minus sign problem`` of dynamical fermions which has made Monte Carlo simulation very difficult. We demonstrate that for small values of the hole hopping parameter one can extract the entire hole dispersion relation using the GRW Monte Carlo algorithm, which is a simulation of the Euclidean time Schroedinger equation, and present results on 4 {times} 4 and 6 {times} 6 lattices. Generalization to physical hopping parameter values wig only require use of an improved trial wavefunction for importance sampling.

  18. Radiochemical purity of Mo and Tc solution obtained after irradiation and dissolution of Mo-100-enriched and ultra-high-purity natural Mo disks

    Energy Technology Data Exchange (ETDEWEB)

    Tkac, Peter [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States); Chemerisov, Sergey D. [Argonne National Lab. (ANL), Argonne, IL (United States); Rotsch, David A. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-09-01

    Four irradiations of ultra-high-purity natural Mo targets and one irradiation using 97.4% Mo-100-enriched material were performed. The purpose of these irradiations was to determine whether the presence of Sn stabilizer in the H2O2 used for the dissolution of sintered Mo disks can affect the radiochemical purity of the final K2MoO4 in 5M KOH solution. Results from radiochemical purity tests performed using thin-layer paper chromatography show that even 2– 3× excess of Sn-stabilized H2O2 typically used for dissolution of sintered Mo disks did not affect the radiochemical purity of the final product.

  19. A Novel Ternary Ligand System Useful for Preparation of Cationic 99mTc-Diazenido Complexes and 99mTc-Labeling of Small Biomolecules

    Science.gov (United States)

    Kim, Young-Seung; He, Zhengjie; Hsieh, Wen-Yuan; Liu, Shuang

    2008-01-01

    This report describes a novel ternary ligand system composed of a phenylhydrazine, a crown ether-containing dithiocarbamate (DTC) and a PNP-type bisphosphine (PNP). The combination of three different ligands with 99mTc results in cationic 99mTc-diazenido complexes,[99mTc(NNAr)(DTC)(PNP)]+, with potential radiopharmaceuticals for heart imaging. Synthesis of cationic 99mTc-diazenido complexes can be accomplished in two steps with high yield. For example, the reaction of phenylhydrazine with 99mTcO4− at 100 °C in the presence of excess stannous chloride and 1,2-diaminopropane-N,N,N’,N’-tetraacetic acid (PDTA) results in the [99mTc(NNPh)(PDTA)n] intermediate, which then reacts with sodium N-(dithiocarbamato)-2-aminimethyl-15-Crown-5 (L4) and N,N-bis[2-(bis(3-ethoxypropyl)phosphino)ethyl]ethoxy-ethylamine (PNP6) at 100 °C for 15 min to give the complex, [99mTc(NNPh)(L4)(PNP6)]+ in high yield (> 90%). Cationic complexes [99mTc(NNPh)(DTC)(PNP)]+ are stable for ≥6 h. Their composition was determined to be 1:1:1:1 for Tc:NNPh:DTC:PNP using the mixed-ligand experiments on the tracer (99mTc) level, and was further confirmed by the ESI-MS spectral data of a model compound [Re(NNPh)(L4)(L6)]+. It was found that both DTCs and bisphosphines have a significant impact on the lipophilicity of their cationic 99mTc-diazenido complexes. Results from a 99mTc-labeling efficiency experiment showed that 4-hydrazinobenzoic acid (HYBA) might be useful as a bifunctional coupling agent for 99mTc-labeling of small biomolecules. However, the 99mTc-labeling efficiency of HYBA is much lower than that of 6-hydrazinonicotinic acid (HYNIC) with tricine and trisodium triphenylphosphine-3,3’,3”-trisulfonate (TPPTS) as coligands. PMID:16536480

  20. Inflammatory breast cancer: High incidence of GCC haplotypes (-1082A/G, -819T/C, and -592A/C) in the interleukin-10 gene promoter correlates with over-expression of interleukin-10 in patients' carcinoma tissues.

    Science.gov (United States)

    Sabet, Salwa; El-Sayed, Shrouk Khalaf; Mohamed, Hossam Taha; El-Shinawi, Mohamed; Mohamed, Mona M

    2017-07-01

    Interleukin-10 is involved in carcinogenesis by supporting tumor escape from the immune response. The aim of this study was to assess the single nucleotide polymorphisms, -1082A/G, -819T/C and -592A/C, in interleukin-10 gene promoter in inflammatory breast cancer compared to non-inflammatory breast cancer and association of these polymorphisms with interleukin-10 gene expression. We enrolled 105 breast cancer tissue (72 non-inflammatory breast cancer and 33 inflammatory breast cancer) patients and we determined the three studied single nucleotide polymorphisms in all samples by polymerase chain reaction restriction fragment length polymorphism and investigated their association with the disease and with various prognostic factors. In addition, we assessed the expression of interleukin-10 gene by real-time quantitative reverse transcription polymerase chain reaction and the correlation between studied single nucleotide polymorphisms and interleukin-10 messenger RNA expression. We found co-dominant effect as the best inheritance model (in the three studied single nucleotide polymorphisms in non-inflammatory breast cancer and inflammatory breast cancer samples), and we didn't identify any association between single nucleotide polymorphisms genotypes and breast cancer prognostic factors. However, GCC haplotype was found highly associated with inflammatory breast cancer risk (p interleukin-10 messenger RNA was significantly higher (p interleukin-10 gene expression (r = 0.9, p < 0.001).

  1. Optimization of the detection coil of high-Tc superconducting quantum interference device-based nuclear magnetic resonance for discriminating a minimum amount of liver tumor of rats in microtesla fields

    Science.gov (United States)

    Chen, Hsin-Hsien; Huang, Kai-Wen; Yang, Hong-Chang; Horng, Herng-Er; Liao, Shu-Hsien

    2013-08-01

    This study presents an optimization of the detection coil of high-Tc superconducting quantum interference device (SQUID)-based nuclear magnetic resonance (NMR) in microtesla fields for discriminating a minimum amount of liver tumor in rats by characterizing the longitudinal relaxation rate, T1-1, of tested samples. The detection coil, which was coupled to the SQUID through a flux transformer, was optimized by varying the copper wires' winding turns and diameters. When comparing the measured NMR signals, we found that the simulated NMR signal agrees with simulated signals. When discriminating liver tumors in rats, the averaged longitudinal relaxation rate was observed to be T1-1 = 3.3 s-1 for cancerous liver tissue and T1-1 = 6.6 s-1 for normal liver tissue. The results suggest that it can be used to successfully discriminate cancerous liver tissue from normal liver tissues in rats. The minimum amount of samples that can be detected is 0.2 g for liver tumor and 0.4 g for normal liver tissue in 100 μT fields. The specimen was not damaged; it can be used for other pathological analyses. The proposed method provides more possibilities for examining undersized specimens.

  2. A first insight into high prevalence of undiagnosed smear-negative pulmonary tuberculosis in Northern Ethiopian prisons: implications for greater investment and quality control.

    Directory of Open Access Journals (Sweden)

    Fantahun Biadglegne

    Full Text Available BACKGROUND: Tuberculosis (TB transmission in prisons poses significant risks to inmates as well as the general population. Currently, there are no data on smear-negative pulmonary TB cases in prisons and by extension no data on the impact such cases have on TB incidence. This study was designed to obtain initial data on the prevalence of smear-negative cases of TB in prisons as well as preliminary risk factor analysis for such TB cases. METHODS: This cross-sectional survey was conducted in November 2013 at eight main prisons located in the state of Amhara, Ethiopia. Interviews using a structured and pretested questionnaire were done first to identify symptomatic prisoners. Three consecutive sputum samples were collected and examined using acid fast bacilli (AFB microscopy at the point of care. All smear-negative sputum samples were taken for culture and Xpert testing. Descriptive and multivariate analysis was done using SPSS version 16. RESULTS: Overall the prevalence of smear-negative pulmonary TB cases in the study prisons was 8% (16/200. Using multivariate analysis, a contact history to TB patients in prison, educational level, cough and night sweating were found to be predictors of TB positivity among smear-negative pulmonary TB cases (p ≤ 0.05. CONCLUSIONS: In the studied prisons, high prevalence of undiagnosed TB cases using AFB microscopy was documented, which is an important public health concern that urgently needs to be addressed. Furthermore, patients with night sweating, non-productive cough, a contact history with TB patients and who are illiterate merit special attention, larger studies are warranted in the future to assess the associations more precisely. Further studies are also needed to examine TB transmission dynamics by patients with smear-negative pulmonary TB in a prison setting.

  3. Greater default-mode network abnormalities compared to high order visual processing systems in amnestic mild cognitive impairment: an integrated multi-modal MRI study.

    Science.gov (United States)

    Sala-Llonch, Roser; Bosch, Beatriz; Arenaza-Urquijo, Eider M; Rami, Lorena; Bargalló, Núria; Junqué, Carme; Molinuevo, José-Luis; Bartrés-Faz, David

    2010-01-01

    We conducted an integrated multi-modal magnetic resonance imaging (MRI) study based on functional MRI (fMRI) data during a complex but cognitively preserved visual task in 15 amnestic mild cognitive impairment (a-MCI) patients and 15 Healthy Elders (HE). Independent Component Analysis of fMRI data identified a functional network containing an Activation Task Related Pattern (ATRP), including regions of the dorsal and ventral visual stream, and a Deactivation Task Related Pattern network (DTRP), with high spatial correspondence with the default-mode network (DMN). Gray matter (GM) volumes of the underlying ATRP and DTRP cortical areas were measured, and probabilistic tractography (based on diffusion MRI) identified fiber pathways within each functional network. For the ATRP network, a-MCI patients exhibited increased fMRI responses in inferior-ventral visual areas, possibly reflecting compensatory activations for more compromised dorsal regions. However, no significant GM or white matter group differences were observed within the ATRP network. For the DTRP/DMN, a-MCI showed deactivation deficits and reduced GM volumes in the posterior cingulate/precuneus, excessive deactivations in the inferior parietal lobe, and less fiber tract integrity in the cingulate bundles. Task performance correlated with DTRP-functionality in the HE group. Besides allowing the identification of functional reorganizations in the cortical network directly processing the task-stimuli, these findings highlight the importance of conducting integrated multi-modal MRI studies in MCI based on spared cognitive domains in order to identify functional abnormalities in critical areas of the DMN and their precise anatomical substrates. These latter findings may reflect early neuroimaging biomarkers in dementia.

  4. Greater impact of acute high-intensity interval exercise on post-exercise executive function compared to moderate-intensity continuous exercise.

    Science.gov (United States)

    Tsukamoto, Hayato; Suga, Tadashi; Takenaka, Saki; Tanaka, Daichi; Takeuchi, Tatsuya; Hamaoka, Takafumi; Isaka, Tadao; Hashimoto, Takeshi

    2016-03-01

    Aerobic moderate-intensity continuous exercise (MCE) can improve executive function (EF) acutely, potentially through the activation of both physiological and psychological factors. Recently, high-intensity interval exercise (HIIE) has been reported to be more beneficial for physical adaptation than MCE. Factors for EF improvement can potentially be more enhanced by HIIE than by MCE; but the effects of HIIE on EF remain unknown. Therefore, we aimed to examine to what extent HIIE impacts post-exercise EF immediately after exercise and during post-exercise recovery, compared with traditional MCE. Twelve healthy male subjects performed cycle ergometer exercise based on either HIIE or MCE protocols in a randomized and counterbalanced order. The HIIE protocol consisted of four 4-min bouts at 90% of peak VO2 with 3-min active recovery at 60% of peak VO2. A volume-matched MCE protocol was applied at 60% of peak VO2. To evaluate EF, a color-words Stroop task was performed pre- and post-exercise. Improvement in EF immediately after exercise was the same for the HIIE and MCE protocols. However, the improvement of EF by HIIE was sustained during 30 min of post-exercise recovery, during which MCE returned to the pre-exercise level. The EF response in the post-exercise recovery was associated with changes in physiological and psychological responses. The present findings showed that HIIE and MCE were capable of improving EF. Moreover, HIIE could prolong improvement in EF during post-exercise recovery. For the first time, we suggest that HIIE may be more effective strategy than MCE for improving EF.

  5. Clinical indications to the use of (99m)Tc-EDDA/HYNIC-TOC to detect somatostatin receptor-positive neuroendocrine tumors.

    Science.gov (United States)

    Parisella, M G; Chianelli, M; D'Alessandria, C; Todino, V; Mikolajczak, R; Papini, E; Dierckx, R A; Scopinaro, F; Signore, A

    2012-02-01

    The aim of this study was to define, retrospectively, the utility to perform (99m)Tc-EDDA/HYNIC-Tyr3-octreotide ((99m)Tc-EDDA/HYNIC-TOC) scan in patients with NET. We studied 50 consecutive patients affected by different types of NET and divided in two groups. Group 1: 34 patients with known lesions in which (99m)Tc-EDDA/HYNIC-TOC was performed for staging, characterisation or to choose the appropriate treatment. Group 2: 16 patients suspected of having NET or in follow up after surgery. Patients were injected with 370 MBq of (99m)Tc-EDDA/HYNIC-Tyr3-octreotide and whole-body and SPET images acquired 2-3 hours after injection. Overall, 29 patients (58%) had a positive scan, with a sensitivity, specificity and accuracy of 70.3%, 76.9% and 72%, respectively (78.1%, 50% and 76.5%, in group 1 and 20%, 81.2%, 62.5% in group 2). In patients from group 1 (99m)Tc-HYNIC-TOC scintigraphy showed a concordance of 68% with another imaging procedure and in 9 patients revealed a greater number of lesions. In the second group, false negative results were especially found in patients with medullary thyroid cancer with negative radiological findings and elevated calcitonin. In conclusion, (99m)Tc-EDDA/HYNIC-TOC is highly indicated for in vivo histological characterization of known NET lesions, previously identified by other imaging modalities or biopsy, to plan appropriate therapy especially for patients with inoperable disease. In patients with only biochemical suspicion of NET and in those with negative markers, this scintigraphy does not significantly modify the clinical management.

  6. High HIV incidence among persons who inject drugs in Pakistan: greater risk with needle sharing and injecting frequently among the homeless.

    Directory of Open Access Journals (Sweden)

    Rab Nawaz Samo

    Full Text Available BACKGROUND: The incidence of HIV among persons who inject drugs (PWIDU has fallen in many nations, likely due to successes of clean needle/syringe exchange and substance abuse treatment and service programs. However in Pakistan, prevalence rates for PWID have risen dramatically. In several cities, prevalence exceeded 20% by 2009 compared to a 2003 baseline of just 0.5%. However, no cohort study of PWID has ever been conducted. METHODS: We enrolled a cohort of 636 HIV seronegative PWID registered with three drop-in centers that focus on risk reduction and basic social services in Karachi. Recruitment began in 2009 (March to June and PWID were followed for two years. We measured incidence rates and risk factors associated with HIV seroconversion. RESULTS: Incidence of HIV was 12.4 per 100 person-years (95% exact Poisson confidence interval [CI]: 10.3-14.9. We followed 474 of 636 HIV seronegative persons (74.5% for two years, an annual loss to follow-up of <13 per 100 person years. In multivariable Cox regression analysis, HIV seroconversion was associated with non-Muslim religion (Adjusted risk ratio [ARR] = 1.7, 95%CI:1.4, 2.7, p = 0.03, sharing of syringes (AR  = 2.3, 95%CI:1.5, 3.3, p<0.0001, being homeless (ARR = 1.7, 95%CI:1.1, 2.5, p = 0.009, and daily injection of drugs (ARR = 1.1, 95%CI:1.0, 1.3, p = 0.04. CONCLUSIONS: Even though all members of the cohort of PWID were attending risk reduction programs, the HIV incidence rate was very high in Karachi from 2009-2011. The project budget was low, yet we were able to retain three-quarters of the population over two years. Absence of opiate substitution therapy and incomplete needle/syringe exchange coverage undermines success in HIV risk reduction.

  7. Beta decay of {sup 111}Tc to {sup 111}Ru

    Energy Technology Data Exchange (ETDEWEB)

    Pfeiffer, B.; Kloeckl, I.; Kratz, K.L. [Mainz Univ. (Germany). Inst. fuer Kernchemie; Lhersonneauc, G.; Dendooven, P.; Honkanen, A.; Huhta, M.; Oinonen, M.; Penttilae, H.; Peraejaervi, K.; Wang, J.C.; Aeystoe, J. [Department of Physics, University of Jyvaeskylae, P.O.Box 35, FIN-40351 Jyvaeskylae (Finland); Persson, J.R. [School of Physics and Space Research, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

    1998-05-01

    The {beta}-decay of the very neutron-rich {sup 111}Tc nucleus has been observed. A partial decay scheme of {sup 111}Ru is presented, complementing the high-spin levels earlier reported in spontaneous fission work. (orig.) With 1 fig., 2 tabs., 20 refs.

  8. Potential value of color-coded dynamic breast-specific gamma-imaging; comparing {sup 99m}Tc-(V)-DMSA, {sup 99m}Tc-MIBI, and {sup 99m}Tc-HDP in a mouse mammary tumor model

    Energy Technology Data Exchange (ETDEWEB)

    Leeuwen, Fijs W.B. van, E-mail: fw.v.leeuwen@nki.n [Departments of Radiology and Nuclear Medicine, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, 1066 CX Amsterdam (Netherlands); Buckle, Tessa; Batteau, Lukas; Pool, Bert; Sinaasappel, Michiel [Departments of Radiology and Nuclear Medicine, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, 1066 CX Amsterdam (Netherlands); Jonkers, Jos [Department of Molecular Biology, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, 1066 CX Amsterdam (Netherlands); Gilhuijs, Kenneth G.A. [Departments of Radiology and Nuclear Medicine, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, 1066 CX Amsterdam (Netherlands)

    2010-12-15

    Using a mouse mammary tumor model based on orthotopic transplantation of luciferase-expressing mouse ILC cells (KEP1-Luc cells), we evaluated the diagnostic value of three clinically applied tracers: {sup 99m}Tc-(V)-DMSA, {sup 99m}Tc-MIBI, and {sup 99m}Tc-HDP. Uptake of the tracers is compared using static and dynamic imaging procedures. We found that dynamic imaging in combination with pixel-by-pixel color coding has an added value over (high resolution) static imaging procedures. Such dynamic imaging procedures could enhance the potential of breast-specific gamma-imaging.

  9. Tc-99 Ion Exchange Resin Testing

    Energy Technology Data Exchange (ETDEWEB)

    Valenta, Michelle M.; Parker, Kent E.; Pierce, Eric M.

    2010-08-01

    Pacific Northwest National Laboratory was contracted by CHPRC to evaluate the release of 99Tc from spent resin used to treat water from well 299-W15-765 and stored for several years. The key questions to be answered are: 1) does 99Tc readily release from the spent ion exchange resin after being in storage for several years; 2) if hot water stripping is used to remove the co-contaminant carbon tetrachloride, will 99Tc that has been sequestered by the resin be released; and 3) can spent resin be encapsulated into a cementitious waste form; if so, how much 99Tc would be released from the weathering of the monolith waste form? The results from the long term stability leach test results confirm that the resin is not releasing a significant amount of the sequestered 99Tc, evident by the less than 0.02% of the total 99Tc loaded being identified in the solution. Furthermore, it is possible that the measured 99Tc concentration is the result of 99Tc contained in the pore spaces of the resin. In addition to these results, analyses conducted to examine the impact of hot water on the release of 99Tc suggest that only a small percentage of the total is being released. This suggest that hot water stripping to remove carbon tetrachloride will not have a significant affect on the resin’s ability to hold-on to sequestered 99Tc. Finally, encapsulation of spent resin in a cementitious material may be a viable disposal option, but additional tests are needed to examine the extent of physical degradation caused by moisture loss and the effect this degradation process can have on the release of 99Tc.

  10. Expression and Characterization of Catalytic Domain of T Cell Protein Tyrosine Phosphatase(ΔTC-PTP)——Immunohistochemical Study of ΔTC-PTP Expression in Non-small Cell Lung Carcinomas

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhi-cheng; SUN Mei; ZHANG Xing-yi; LIU Ke-xiang; SHI Dong-lei; LI Jin-dong; SU Ji-quan; XU Yue-chi; FU Xue-qi

    2007-01-01

    This study objective was to express and characterize the catalytic domain of the human T cell protein tyrosine phosphatase(ΔTC-PTP) and to study immunohistochemically the expression of ΔTC-PTP in human non-small cell lung cancers. ΔTC-PTP gene was PCR amplified with the cDNA of human TC-PTP as template, and cloned into the pT7 expression vector. The recombinant pT7-ΔTC-PTP was expressed in E.coli Rosetta(DE3) host cells and purified. The enzymatic characteristics of ΔTC-PTP including enzyme activity and kinetics assay were measured. The antiserum was prepared by immunizing rabbit with the purified recombinant ΔTC-PTP. Rabbit polyclonal antibody against ΔTC-PTP was purified by PVDF immobilized antigen affinity chromatography. Immunohistochemical staining of lung cancer tissues was performed with antibody against ΔTC-PTP protein. ΔTC-PTP gene was correctly cloned, expressed, and purified. The recombinant ΔTC-PTP had a highly catalytic activity of PTPase. Squamous cell lung carcinoma showed a significantly higher expression rate of ΔTC-PTP(76.92%, 10/13) than adenocarcinoma(57.14%, 4/7) and normal lung tissue(20%, 1/5). This study represents the first demonstration that ΔTC-PTP is highly expressed in human squamous cell lung carcinomas. In addition, this study provides an important basis for further studying the biological function of TC-PTP and its relationship with lung carcinomas and other diseases.

  11. Estudio de la variación de la permeabilidad de la dentina radicular usando isótopos 99mTc, después de la aplicación de láser de alta intensidad Study of the dentin root permeability variation using 99mTc isotopes, after the application of high intensity laser

    Directory of Open Access Journals (Sweden)

    R. Cabrales Salgado

    2012-02-01

    Full Text Available Objetivo: Este estudio tuvo como objetivo evaluar las variaciones de la permeabilidad dentinaria radicular de dientes humanos después del preparo químico-quirúrgico e irradiación con láser de Er: YAG, Nd: YAG, a través de la utilización del radioisótopo tecnecio-99m (99mTc libre. Materiales y métodos: Canales de treinta raíces palatinas de primeros premolares superiores humanos fueron preparados y divididos, aleatoriamente, en 3 grupos experimentales: G1 (control, G2 (irradiación con láser de Er: YAG y G3 (irradiación con láser de Nd: YAG. Las muestras recibieron en el interior del canal radicular, 99mTc libre en cantidad suficiente para el llenado y colocados en tubos de ensayo contiendo 1 ml de solución salina. Después de 1 hora, la cuenta del isótopo radioactivo (99mTc fue realizada. Resultados: Después del análisis estadístico (ANOVA, fue verificado que los mejores resultados obtenidos en cuanto a la disminución de la permeabilidad se encontraron en el Grupo 3, seguido del Grupo 2 y del Grupo 1. Conclusión: Concluimos que irradiación con láser de Nd: YAG provocó una disminución significativa de la permeabilidad dentinaria del canal radicular. El láser de Er: YAG y el control en relación a la permeabilidad de la dentina de las paredes del canal radicular no presentaron diferencias estadísticamente significativas a nivel de 5%.Objective: The objective of this study was to evaluate changes in root dentin permeability of human teeth after chemical-surgical preparation, and laser irradiation with Er: YAG, Nd: YAG, through the use of the radioisotope technetium-99m (99mTc free. Materials and methods: thirty Channels palatal roots of human maxillary first premolars were prepared and divided randomly into three experimental groups: G1 (control, G2 (laser irradiation with Er: YAG and G3 (Nd laser irradiation : YAG. in the samples were deposited 99mTc free inside the root canal, enough to fill and placed in test tubes

  12. High Tc superconducting small loop antenna

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Z.; Mehler, M.J.; Maclean, T.S.M.; Lancaster, M.J.; Gough, C.E. (Univ. of Birmingham (UK)); Alford, N. (I.C.I. Advanced Materials Div., Runcorn (UK))

    1989-12-01

    The improvement in the radiation efficiency of an electrically small loop antenna is analysed when it is fabricated from a superconductor, and experimental results for a liquid nitrogen cooled, ceramic superconducting loop at 450MHz are presented. (orig.).

  13. Anisotropic flux pinning in high Tc superconductors

    Science.gov (United States)

    Koleśnik, S.; Igalson, J.; Skośkiewicz, T.; Szymczak, R.; Baran, M.; Pytel, K.; Pytel, B.

    1995-02-01

    In this paper we present a comparison of the results of FC magnetization measurements on several PbSr(Y,Ca)CuO crystals representing various levels of flux pinning. The pinning centers in our crystals have been set up during the crystal growth process or introduced by neutron irradiation. Some possible explanations of the observed effects, including surface barrier, flux-center distribution and sample-shape effects, are discussed.

  14. Dielectric response in high Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Aguilar, F.; Costa-Quintana, J.; Febrero, F.; Aurell, M.T.; Sanchez, A.; Munoz, J.S. (Dept. de Fisica, Grupo de Electromagnetismo, Univ. Autonoma de Barcelona (Spain)); Balle, S. (Dept. de Fisica, Univ. de les Illes Balears, Palma de Mallorca (Spain))

    1989-12-01

    The random phase approximation integral equation is solved for obtaining the dynamically screened interaction between d electrons (W{sub d}({omega})), p electrons (W{sub p}({omega})) and p/d electrons (W{sub pd}({omega})). Some characteristic divergences of this last interaction correspond to the plasmon frequencies which one can relate with the effective masses of the p and d electrons close to E{sub F} by means of the relation {omega}{sub p1}/{omega}{sub p2} = (m{sub 2}/m{sub 1}){sup 1/2}. Another feature of this W{sub pd}({omega}) interaction is the attractive character for low frequencies. The lowest frequency for which {epsilon}{sub pd} = 0 decreases when the localization of states close to E{sub F} arising from the x{sup 2}-y{sup 2} symmetry increases. (orig.).

  15. High-Tc spin superfluidity in antiferromagnets.

    Science.gov (United States)

    Bunkov, Yu M; Alakshin, E M; Gazizulin, R R; Klochkov, A V; Kuzmin, V V; L'vov, V S; Tagirov, M S

    2012-04-27

    We report the observation of the unusual behavior of induction decay signals in antiferromagnetic monocrystals with Suhl-Nakamura interactions. The signals show the formation of the Bose-Einstein condensation (BEC) of magnons and the existence of spin supercurrent, in complete analogy with the spin superfluidity in the superfluid (3)He and the atomic BEC of quantum gases. In the experiments described here, the temperature of the magnon BEC is a thousand times larger than in the superfluid (3)He. It opens a possibility to apply the spin supercurrent for various magnetic spintronics applications.

  16. TC-1 Satellite of DSP Delivered

    Institute of Scientific and Technical Information of China (English)

    SunQing

    2004-01-01

    TC-1 satellite of Double Star Program (DSP), a near-earth equatorial satellite, was delivered to the representative of the end user, the Research Center for Space Science and Application under the Chinese Academy of Sciences (CAS) on April 12, 2004, which symbolized that TC-1 satellite was put into operation formally.

  17. Hepatic blood flow determination. A comparison of 99mTc-diethyl-IDA and indocyanine green as hepatic blood flow indicators in man

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Winkler, K

    1987-01-01

    99mTc-diethyl-acetanilide-iminodiacetic acid (IDA) was compared with indocyanine green (ICG) as an indicator of hepatic blood flow (HBF). Twelve subjects (8 with cirrhosis, 2 with fatty liver, one with pancreatitis, and one with intestinal angina) were studied during hepatic vein catheterization....... In 9 subjects the HBF measurements (indirect Fick-principle) were within 0.8-1.9 l/min, and no significant difference was observed between the values obtained by ICG and 99mTc-diethyl-IDA (mean 1.24 vs 1.26 l/min, P greater than 0.4). In 2 subjects with cirrhosis very high but almost identical values...... were found with the two indicators. In one subject ICG could not be measured in plasma because of hyperlipidaemia, but HBF was easily determined by 99mTc-diethyl-IDA. The results indicate that 99mTc-diethyl-IDA can be used as an indicator of HBF. This indicator is not superior to ICG in patients...

  18. TcCYPR04, a Cacao Papain-Like Cysteine-Protease Detected in Senescent and Necrotic Tissues Interacts with a Cystatin TcCYS4.

    Science.gov (United States)

    Cardoso, Thyago Hermylly Santana; Freitas, Ana Camila Oliveira; Andrade, Bruno Silva; Sousa, Aurizangela Oliveira de; Santiago, André da Silva; Koop, Daniela Martins; Gramacho, Karina Peres; Alvim, Fátima Cerqueira; Micheli, Fabienne; Pirovani, Carlos Priminho

    2015-01-01

    The interaction amongst papain-like cysteine-proteases (PLCP) and their substrates and inhibitors, such as cystatins, can be perceived as part of the molecular battlefield in plant-pathogen interaction. In cacao, four cystatins were identified and characterized by our group. We identified 448 proteases in cacao genome, whereof 134 were cysteine-proteases. We expressed in Escherichia coli a PLCP from cacao, named TcCYSPR04. Immunoblottings with anti-TcCYSPR04 exhibited protein increases during leaf development. Additional isoforms of TcCYSPR04 appeared in senescent leaves and cacao tissues infected by Moniliophthora perniciosa during the transition from the biotrophic to the saprophytic phase. TcCYSPR04 was induced in the apoplastic fluid of Catongo and TSH1188 cacao genotypes, susceptible and resistant to M. perniciosa, respectively, but greater intensity and additional isoforms were observed in TSH1188. The fungal protein MpNEP induced PLCP isoform expression in tobacco leaves, according to the cross reaction with anti-TcCYSPR04. Several protein isoforms were detected at 72 hours after treatment with MpNEP. We captured an active PLCP from cacao tissues, using a recombinant cacao cystatin immobilized in CNBr-Sepharose. Mass spectrometry showed that this protein corresponds to TcCYSPR04. A homology modeling was obtained for both proteins. In order to become active, TcCYSPR04 needs to lose its inhibitory domain. Molecular docking showed the physical-chemical complementarities of the interaction between the cacao enzyme and its inhibitor. We propose that TcCYSPR04 and its interactions with cacao cystatins are involved in the senescence and necrosis events related to witches' broom symptoms. This molecular interaction may be the target for future interventions to control witches' broom disease.

  19. Scintillating 99Tc Selective Ion Exchange Resins

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell Greenhalgh; Richard D. Tillotson

    2012-07-01

    Scintillating technetium (99Tc) selective ion exchange resins have been developed and evaluated for equilibrium capacities and detection efficiencies. These resins can be utilized for the in-situ concentration and detection of low levels of pertechnetate anions (99TcO4-) in natural waters. Three different polystyrene type resin support materials were impregnated with varying amounts of tricaprylmethylammonium chloride (Aliquat 336) extractant, several different scintillating fluors and wavelength shifters. The prepared resins were contacted batch-wise to equilibrium over a wide range of 99TcO4- concentrations in natural water. The measured capacities were used to develop Langmuir adsorption isotherms for each resin. 99Tc detection efficiencies were determined and up to 71.4 ± 2.6% was achieved with some resins. The results demonstrate that a low level detection limit for 99TcO4- in natural waters can be realized.

  20. Spin polarization effect for Tc2 molecule

    Institute of Scientific and Technical Information of China (English)

    Yan Shi-Ying; Zhu Zheng-He

    2004-01-01

    Density functional method (DFT) (B3p86) of Gaussian98 has been used to optimize the structure of the Tc2 molecule. The result shows that the ground state for Tc2 molecule is an 11-multiple state and its electronic configuration is 11∑- g, which shows the spin polarization effect of Tc2 molecule of a transition metal element for the first time.Meanwhile, we have not found any spin pollution because the wavefunction of the ground state does not mingle with wavefunctions of higher energy states. So, that the ground state for Tc2 molecule is an 11-multiple state is indicative of the spin polarization effect of Tc2 molecule of a transition metal element: that is, there exist 10 parallel spin electrons. The non-conjugated electron is greatest in number. These electrons occupy different spacious tracks, so that the energy of Tc2 molecule is minimized. It can be concluded that the effect of parallel spin of the Tc2 molecule is larger than the effect of the conjugated molecule, which is obviously related to the effect of electron d delocalization.In addition, the Murrell-Sorbie potential functions with the parameters for the ground state 11∑- g and other states of Tc2 molecule are derived. Dissociation energy De for the ground state of Tc2 molecule is 2.266eV, equilibrium bond length Re is 0.2841nm, vibration frequency ωe is 178.52cm-1. Its force constants f2, f3, and f4 are 0.9200aJ.nm-2,-3.5700aJ.nm-3, 11.2748aJ.nm-4 respectively. The other spectroscopic data for the ground state of Tc2 molecule ωexe,Be, αe are 0.5523cm- 1, 0.0426cm- 1, 1.6331 × 10-4cm- 1 respectively.

  1. The function of Sn(II)-apatite as a Tc immobilizing agent

    Energy Technology Data Exchange (ETDEWEB)

    Asmussen, R. Matthew; Neeway, James J.; Lawter, Amanda R.; Levitskaia, Tatiana G.; Lukens, Wayne W.; Qafoku, Nikolla P.

    2016-11-01

    Technetium-99 is a radioactive contaminant of high concern at many nuclear waste storage sites. At the U.S. Department of Energy Hanford Site, 99Tc is a component of low-activity waste (LAW) fractions of the nuclear tank waste, which are highly caustic, high ionic strength and have high concentrations of chromate. Removal of 99Tc from LAW streams would greatly benefit the site remediation process. In this study, we investigated the removal of 99Tc(VII), as pertechnetate, from deionized water (DIW) and a LAW simulant using two solid sorbents, tin (II) apatite (Sn-A) and SnCl2 through batch sorption testing and solid phase characterization. Sn-A showed higher levels of removal of Tc from both DIW and LAW simulant compared with the SnCl2. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/XEDS) and X-ray adsorption spectroscopy (XAS) of Sn-A following batch experiments in DIW showed that TcO4- is reduced to Tc(IV) on the Sn-A surface with no incorporation into the lattice structure of Sn-A. The performance of Sn-A in the LAW simulant was lowered due to a combined effect of the high alkalinity, which lead to an increased dissolution of Sn from the Sn-A, and a preference for the reduction of Cr(VI) over Tc(VII).

  2. TC10 is regulated by caveolin in 3T3-L1 adipocytes.

    Directory of Open Access Journals (Sweden)

    Dave Bridges

    Full Text Available BACKGROUND: TC10 is a small GTPase found in lipid raft microdomains of adipocytes. The protein undergoes activation in response to insulin, and plays a key role in the regulation of glucose uptake by the hormone. METHODOLOGY/PRINCIPAL FINDINGS: TC10 requires high concentrations of magnesium in order to stabilize guanine nucleotide binding. Kinetic analysis of this process revealed that magnesium acutely decreased the nucleotide release and exchange rates of TC10, suggesting that the G protein may behave as a rapidly exchanging, and therefore active protein in vivo. However, in adipocytes, the activity of TC10 is not constitutive, indicating that mechanisms must exist to maintain the G protein in a low activity state in untreated cells. Thus, we searched for proteins that might bind to and stabilize TC10 in the inactive state. We found that Caveolin interacts with TC10 only when GDP-bound and stabilizes GDP binding. Moreover, knockdown of Caveolin 1 in 3T3-L1 adipocytes increased the basal activity state of TC10. CONCLUSIONS/SIGNIFICANCE: Together these data suggest that TC10 is intrinsically active in vivo, but is maintained in the inactive state by binding to Caveolin 1 in 3T3-L1 adipocytes under basal conditions, permitting its activation by insulin.

  3. Preparation and Biodistribution of 99mTc-Pamidronate as Bone Imaging Agent

    Directory of Open Access Journals (Sweden)

    LUO Hong-yi

    2016-02-01

    Full Text Available Labeling of Pamidronate (PAM with 99mTc was studied by a direct labeling method in the presence of SnCl2•2H2O as reducing agent. The influences of the concentration of SnCl2•2H2O, PAM concentration and pH value, reaction time on labeling yield were investigated. The optimum labeling was determined. The results showed that the radiochemistry purity of 99mTc-PAM was more than 95%. Biodistribution studies in normal mice and rats showed very high uptake of 99mTc-PAM and long retain in bone. 99mTc-PAM was washed out from the blood very quickly. In addition, considerable uptake in the kidneys indicated this complex was excreted mainly by renal pathway. On the other hand, the radioactivity in liver, lung and heart was negligible. It could be known from SPECT images that 99mTc-PAM would be an excellent bone-imaging agent. Bone uptake of 99mTc-PAM was higher than that of 99mTc-MDP in mice. This study suggested that 99mTc-PAM was a promising bone imaging agent and further study was worthwhile.

  4. Impact of bidentate chelators on lipophilicity, stability, and biodistribution characteristics of cationic 99mTc-nitrido complexes.

    Science.gov (United States)

    Kim, Young-Seung; He, Zhengjie; Hsieh, Wen-Yuan; Liu, Shuang

    2007-01-01

    This report describes synthesis and evaluation of novel cationic 99mTc-nitrido complexes, [99mTcN(L)(PNP)](+) (L = ma, ema, tma, etma and mpo; PNP = PNP5, PNP6, and L6), as potential radiotracers for heart imaging. Cationic complexes [99mTcN(L)(PNP)](+) were prepared in two steps. For example, reaction of succinic dihydrazide with 99mTcO4(-) in the presence of excess stannous chloride and PDTA resulted in the [99mTcN(PDTA)n] intermediate, which then reacted Hmpo and PNP6 at 100 degrees C for 10-15 min to give [99mTcN(mpo)(PNP6)](+) in >90% yield. It was found that bidentate chelators have a significant impact on lipophilicity, solution stability, biodistribution, and metabolic stability of cationic 99mTc-nitrido complexes. The fact that [99mTcN(ema)(PNP6)](+) decomposes rapidly in the presence of cysteine (1 mg/mL) while [99mTcN(etma)(PNP6)](+) and [99mTcN(mpo)(PNP6)](+) remain stable for >6 h under the same conditions strongly suggests that thione-S donors in bidentate chelators increase the solution stability of their cationic 99mTc-nitrido complexes. Biodistribution studies were performed on four cationic 99mTc-nitrido complexes in Sprague-Dawley rats. [99mTcN(etma)(PNP5)](+) is of particular interest due to its high initial heart uptake (1.81 +/- 0.35 %ID/g at 5 min postinjection), and long myocardial retention (1.99 +/- 0.47 %ID/g at 120 min postinjection). The heart/liver ratio of [99mTcN(etma)(PNP5)](+) (6.06 +/- 1.48) at 30 min postinjection is almost identical that of 99mTcN-DBODC5 (6.01 +/- 1.45), and is >2 times better than that of 99mTc-sestamibi (2.90 +/- 0.22). Results from metabolism studies show that [99mTcN(etma)(PNP5)](+) has no significant metabolism in the urine, but it does show significant metabolism in feces samples at 120 min postinjection. Planar imaging studies suggest that [99mTcN(etma)(PNP5)](+) might be able to give clinically useful images of the heart as early as 30 min postinjection. [99mTcN(etma)(PNP5)](+) is a very promising

  5. Measure of the magnitude of Young's modulus in whisker-like samples of the Bi-based high-Tc materials Bi sub 2 Sr sub 2 CaCu sub 2 O sub x and Bi sub 2 Sr sub 2 Ca sub 2 Cu sub 3 O sub x

    Energy Technology Data Exchange (ETDEWEB)

    Tritt, T.M.; Ehrlich, A.C.; Gillespie, D.J. (Materials Physics Branch, Naval Research Lab., Washington, DC (USA)); Marone, M.; Chen Xinfen; Skove, M.J.; Tessema, G.X. (Clemson Univ., Dept. of Physics, SC (USA)); Franck, J.P.; Jung, J. (Univ. of Alberta, Dept. of Physics, Edmonton, AB (Canada))

    1991-08-01

    We have measured Young's modulus in ribbon-like whisker samples of the high-Tc materials: Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x} and Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}. This is the first direct measurement of Young's modulus for whiskers of any of the high Tc materials. We used a stress-strain probe that applies an axial force (uniaxial stress) to the whisker-like sample and simultaneously measures the corresponding sample elongation. The slope of the resulting stress-strain curve yields the magnitude of Young's modulus (Y). We found these Bi based high-Tc materials to be soft with Y {approx equal} 20 GPa for Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x} and Y {approx equal} 25 GPa for Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}. (orig.).

  6. Use of 99mTc from a commercial 99Mo/9mTc generator as yield tracer for the determination of 99Tc at low levels

    DEFF Research Database (Denmark)

    Hou, Xiaolin; Jensen, Mikael; Nielsen, Sven Poul

    2007-01-01

    cartridges was investigated to purify the eluate to obtain a suitable Tc-99m tracer with low Tc-99 concentration. The activity ratio of Tc-99/Tc-99m in the prepared Tc-99m solution is lower than 15 x 10(-9), which is higher than the theoretical ratio of less than 10 x 10(-9). The possible reason is discussed......) 2007 Elsevier Ltd. All rights reserved....

  7. Studies of Long-lived Radionuclides in the Environment - with Emphasis on {sup 99}Tc, {sup 237}Np and Pu Isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Lindahl, Patric

    2003-03-01

    Studies of the long-lived anthropogenic radionuclides 99Tc, 237Np, 239Pu and 240Pu were performed in marine and terrestrial areas contaminated by different accidental and controlled releases of radioactive materials. The three main sources discussed in this thesis are nuclear weapons tests, nuclear reprocessing plants and the Chernobyl accident. Results are mainly based on measurements of environmental samples collected in different parts of Sweden. An analytical method for trace analysis of plutonium and neptunium in environmental samples using ICP-MS (Inductively Coupled Plasma Mass Spectrometry) is described, and the results compared with those from conventional alpha spectrometry. The use of activated carbon filters for the separation of 99Tc from marine waters, with an adsorption efficiency in the range of 70%, is described. During 1991, 1995 and 2001 brown seaweed samples were collected at several stations along the Swedish west coast. In addition to these locations, a well-defined site (Saerdal; 56.76 deg N, 12.63 deg E) was included from which 99Tc data were collected from 1967 to 2000. The effect of discharges from the Sellafield EARP (Enhanced Actinide Removal Plant) from 1995-1996 was observed in brown seaweed from the Swedish west coast 4-5 years later, with a ten-fold increase in 99Tc activity concentration. An inverse correlation between 99Tc and 137Cs concentrations in seaweed was observed due to continuous mixing of high-Tc-low-Cs (Atlantic Sea) and low-Tc-high-Cs (Baltic Sea) waters. Radioactive materials from the Chernobyl accident contaminated various part of Sweden and by analysing lichen samples from different areas an estimate of the deposited 237Np density could be made. Through the determination of 240Pu/239Pu and 237Np/239Pu atomic ratios, source identification could be made in Swedish lichen samples. In the areas most contaminated by the Chernobyl accident in Sweden, the Chernobyl-derived 237Np contribution was up to 30% of the total

  8. Conscientiousness predicts greater recovery from negative emotion.

    Science.gov (United States)

    Javaras, Kristin N; Schaefer, Stacey M; van Reekum, Carien M; Lapate, Regina C; Greischar, Lawrence L; Bachhuber, David R; Love, Gayle Dienberg; Ryff, Carol D; Davidson, Richard J

    2012-10-01

    Greater levels of conscientiousness have been associated with lower levels of negative affect. We focus on one mechanism through which conscientiousness may decrease negative affect: effective emotion regulation, as reflected by greater recovery from negative stimuli. In 273 adults who were 35-85 years old, we collected self-report measures of personality including conscientiousness and its self-control facet, followed on average 2 years later by psychophysiological measures of emotional reactivity and recovery. Among middle-aged adults (35-65 years old), the measures of conscientiousness and self-control predicted greater recovery from, but not reactivity to, negative emotional stimuli. The effect of conscientiousness and self-control on recovery was not driven by other personality variables or by greater task adherence on the part of high conscientiousness individuals. In addition, the effect was specific to negative emotional stimuli and did not hold for neutral or positive emotional stimuli.

  9. Unconventional normal-state spin dynamics in underdoped high-Tc cuprates as a fingerprint of spiral correlations of localized spins and dual localized/itinerant nature of spin fluctuations

    Science.gov (United States)

    Onufrieva, F.

    2017-03-01

    The paper is motivated by the observation of unusual and not well understood spin dynamics in low- and moderately doped high-Tc cuprates as well as by the discovery in these materials of a static incommensurate order for doping exceeding the insulator-metal boundary in the phase diagram. We develop a microscopic approach that allows us to treat accurately the quantum fluctuations in the spiral state developing upon doping the Mott-Neel insulator. We show that the spiral order of localized spins induces an off-diagonal order of mobile charges and a gap Δ ∝|Q | in their spectrum (Q is the spiral incommensurability wave vector defined with respect to QAF). Due to the dynamic spin-charge interaction the latter gap produces a feedback effect consisting in the appearence of a gap in the coherent spin excitation spectrum. As a result, the characteristic energy ωc=Δ appears, in the spin excitation spectra. It separates two components with qualitatively different behavior-above ωc, spin excitations are magnonlike and have an upward dispersion, below it, they are of the relaxation type and have a slight downward dispersion. The form of the dispersion is close to the form observed experimentally (by inelastic neutron scattering), which can be characterized as OPEN-hour-glass shaped or Y -shaped. There is no qualitative difference between the spin dynamics in the normal and SC states as far as doping is relatively low. There is no resonance. Other important features, including the incommensurability and uniaxial anisotropy of the low-energy spin excitations and the doping dependencies of the characteristic energy and wave vectors, are also close to those observed experimentally in low-doped cuprates. We show that the static spiral state becomes unstable at the critical doping nc. We show also that adopting the hypothesis about the presence of finite-energy spiral correlations in the paramagnetic state above nc and based on the results obtained for the static spiral state

  10. Influence of critical current density on levitation force of high - Tc superconducting system under field cooling condition%临界电流密度对场冷超导磁悬浮力的影响研究

    Institute of Scientific and Technical Information of China (English)

    赵宪锋; 周又和

    2011-01-01

    After the penetration depth of superconducting currents and the internal magnetic field interior of the HTS were calculated, the influence of critical current density (Jc) on the interaction forces between a high - Tc superconductor (HTS) and a permanent magnet (PM) was investigated under field cooling process based on Kim critical state model. It was found that the maximum levitation forces including the attractive force and the repulsive force increased as an exponential function with the increasing of the Jc. They became to saturate at high Jc. The hysteresis energy loss of vertical force - displacement curve under field cooling condition was larger than the one under zero -field cooling condition. There was a force ratio k, which was important on estimating the mechanics capability of superconducting levitation system with large Jc. All these relations could be explained with the penetration history of superconducting currents under field cooling condition.%基于Kim临界态模型,通过考虑超导块材内部屏蔽电流的穿透历史过程,讨论了场冷条件下临界电流密度对高温超导悬浮系统磁悬浮排斥力和吸引力的影响.结果显示:最大超导磁悬浮排斥力和吸引力均随临界电流密度的增加呈指数关系增加,并趋于饱和;场冷条件下的磁悬浮力回滞能量损耗远高于零场冷情况;存在一个磁悬浮力比率κ,κ值对于评价大电流超导磁悬浮系统的机械性能具有重要作用.磁悬浮力随临界电流密度的这些变化特征可以用超导块材内部屏蔽电流的穿透情况进行合理地解释,为高温超导悬浮系统的工业应用提供了重要的理论依据.

  11. Does chronic alcohol use by HIV-infected patients on d4T/3TC/NVP drug regimen effect the HIV viral load and what is the therapeutic window of the drugs, CD4+ count and WBC count in patients with high viral load during the 9 months period of follow up?

    Directory of Open Access Journals (Sweden)

    Godfrey S. Bbosa

    2013-10-01

    Full Text Available The study investigated the effects of chronic alcohol use on HIV viral load in HIV-infected patients on d4T/3TC/NVP drug regimen during 9 months follow up period. It also determined plasma drug concentrations of d4T, 3TC and NVP; CD4+ and WBC counts for patients with high HIV viral load. A case-control study using repeated measures with serial measurements was used. A total of 41 patients (20 alcohol group and 21 control group were screened for alcohol use using WHO AUDIT tool and chronic alcohol use biomarkers. Blood sampling was done at 3 month intervals for a period of 9 months. HIV viral load was determined using Roche Amplicor HIV-1 monitor test, version 1.5 (Amplicor. The d4T, 3TC and NVP concentrations were determined by Shimadzu Class-VPTM HPLC Chromatography data system version 6.1. The CD4+ cell count was determined using FACSCalibur flow cytometer. The WBC was determined using automated hematological Coulter CBC-5 Hematology Analyzer system. Results show that % patients with HIV viral load ≥400 copies/ml in control group was highest (23.8%, n=5 at 3 month while in chronic alcohol use group, it was at 0 month (35%, n=7 for both WHO AUDIT tool and chronic alcohol-use biomarkers groups. Generally patients with high viral load ≥400 copies/ml was observed in chronic alcohol use as compared to control group in both WHO AUDIT tool and biomarkers group despite of patients having high steady state d4T, 3TC and NVP plasma drug concentrations in circulation that is available to suppress HIV virus. The high viral load could be associated with the emergence of resistance of the HIV virus and these patients generally had a low CD4+ cell count. Some of these patients had no detectable d4T plasma drug concentrations in circulation and most of them with high viral load had sub-therapeutic NVP plasma drug concentrations in their blood circulation. Chronic ethanol use by HIV-infected patients on d4T/3TC/NVP drug regimen increased HIV viral load and

  12. Tc-99m-EDDA-HYNIC-TOC somatostatin receptor scintigraphy in patients with carcinoids

    Directory of Open Access Journals (Sweden)

    Vlajković Marina

    2014-11-01

    Full Text Available The aim of this paper is to determine the influence of Ki-67 proliferation index on somatostatin receptor scintigraphy (SSRS with Tc-99m-EDDA-HYNIC-TOC (Tc-99m-Tektrotyd somatostatin analogue in patients with carcinoid tumors. Sixty-one patients (31 female, 30 male; age range: 33-76 years were examined: 13 patients highly suspected of having a carcinoid, and 48 patients who had undergone the surgical removal of the tumor. Whole body SSRS at 4 h postinjection, spot scintigrams and SPECT of the selected regions were obtained for all patients. Tc-99m-Tektrotyd scintigraphy was classified as true positive in 26 out of 30 and true negative in 24 out of 28 patients. The sensitivity of Tc-99mTc-Tektrotyd scintigraphy was found to be as high as 94.74% in the group of patients with low mitotic index Ki67 (20%. The likelihood of Tc-99m-Tektrotyd scan being positive when a carcinoid is present was found to be inversely proportional to the value of Ki67 proliferation index. The results showed that Tc-99m-Tektrotyd SSRS is a sensitive method for diagnosing and staging patients with well-differentiated carcinoid tumors. However, in poorly differentiated tumors with high Ki67 proliferation index, additional analyses are necessary for precise staging.

  13. Removal of TcO4- from Representative Nuclear Waste Streams with Layered Potassium Metal Sulfide Materials

    Energy Technology Data Exchange (ETDEWEB)

    Neeway, James J.; Asmussen, Robert M.; Lawter, Amanda R.; Bowden, Mark E.; Lukens, Wayne W.; Sarma, Debajit; Riley, Brian J.; Kanatzidis, Mercouri G.; Qafoku, Nikolla

    2016-06-01

    Many efforts have focused on the sequestration and immobilization of 99Tc because the radionuclide is highly mobile in oxidizing environments and presents serious health risks due to its radiotoxicity and long half-life (t1/2 = 213 000 a). One of the more common methods for Tc removal from solution and immobilization in solids is based on reducing Tc from highly soluble Tc(VII) to sparingly soluble Tc(IV). In order to remove solution Tc through this reduction process, the Tc-sequestering solid must contain a reducing agent and, ideally, the Tc-sequestering material would function in a large range of chemical environments. For long-term stability, the reduced Tc would preferentially be incorporated into the resulting mineral structure instead of simply being sorbed onto the mineral surface. Here, we report results obtained from batch sorption experiments performed in anoxic and oxic conditions with two sulfide-containing potassium metal sulfide (KMS) materials, known as KMS-2 and KMS-2-SS. In deionized water in anoxic conditions after 15 d of contact, KMS-2 is capable of removing ~45% of Tc and KMS-2-SS is capable of removing ~90% of Tc. The improved performance of KMS-2-SS compared to KMS-2 in deionized water in anoxic conditions appears to be linked both to a higher pH resulting from the batch sorption experiments performed with KMS-2-SS and a higher overall purity of KMS-2-SS. Both materials perform even better in highly caustic (pH~13.5), high ionic strength (8.0 M) simulated Hanford low-activity waste solutions, removing more than 90% Tc after 15 d of contact in anoxic conditions. Post-reaction solids analysis indicate that Tc(VII) is reduced to Tc(IV) and that Tc(IV) is bonded to S atoms in the resulting KMS-2 structure in a Tc2S7 form. In contrast to previous ion exchange experiments with other KMS materials, the batch sorption experiments examining Tc removal cause the initially crystalline KMS materials to lose much of their initial long-range order.

  14. {sup 99m}Tc-MDP and {sup 99m}Tc-MIBI scintimammography in patients with clinically suspicious breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Pai, Moon Sun; Park, Chan H.; Kim, Su Zy; Yoon, Suk Nam; Park, Hee Boong [College of Medicine, Ajou Univ., Suwon (Korea, Republic of)

    1997-07-01

    around the tumor on MDP scan than MIBI scan. The sensitivity of MDP-SM for the detection of breast lesions was 90% and 57% for the lymph node lesion. There were the same in MIBI scintimammography, but the quality of MDP images was inferior to that of MIBI. {sup 99m}Tc-MDP scintimammography can demonstrate malignant breast lesions during the preoperative bone scan with a high accuracy. However, the scan quality is not as good as MIBI scintimammography.

  15. A novel {sup 99m}Tc-labeled dimethyl-substituted zoledronic acid (DMIDP) with improved bone imaging efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, L.; Lin, J.; Luo, S.; Wang, Y.; Cheng, W.; Zhang, S. [Jiangsu Institute of Nuclear Medicine, Wuxi (China). Key Laboratory of Nuclear Medicine

    2012-07-01

    A novel zoledronic acid (ZL) derivative, 1-hydroxy-2-(2,4-dimethyl-1H-imidazol-1-yl)-ethane-1,1-diyldiphosphonic acid (DMIDP, dimezoledronate), was successfully prepared and labeled with {sup 99m}Tc in a high labeling yield. The biodistribution in mice shows that {sup 99m}Tc-DMIDP has significant advantage regarding bone resorption and clearance from soft tissues compared with {sup 99m}Tc-ZL and the clinically widely-used bone-imaging agent {sup 99m}Tc-MDP (methylenediphosphonic acid). Kinetics of blood clearance displayed that distribution half-life (T{sub 1/2{alpha}}) and elimination half-life (T{sub 1/2{beta}}) of {sup 99m}Tc-DMIDP were 2.53 min and 23.53 min, while those of {sup 99m}Tc-ZL were 2.28 and 52.63 min, respectively. Excellent images of the rabbit skeleton can be quickly obtained from {sup 99m}Tc-DMIDP, which was faster than {sup 99m}Tc-ZL and {sup 99m}Tc-MDP. The present findings indicate that {sup 99m}Tc-DMIDP possesses excellent potential for application as a novel bone scanning agent. (orig.)

  16. An electrochemical procedure to concentrate {sup 99m}Tc availed from a zirconium [{sup 99}Mo] molybdate gel generator

    Energy Technology Data Exchange (ETDEWEB)

    Chakravarty, Rubel [Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Sarkar, S.K. [Radiopharmaceuticals Laboratory, Board of Radiation and Isotope Technology, Navi Mumbai 400705 (India); Venkatesh, Meera [Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Dash, Ashutosh, E-mail: adash@barc.gov.in [Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2012-02-15

    Successful use of electrochemical method to concentrate {sup 99m}Tc obtained from a zirconium molybdate (Zr{sup 99}Mo) gel generator is reported. The process consists of electrodeposition of the {sup 99m}Tc in an oxalate bath on a small platinum electrode followed by recovery of {sup 99m}Tc in a small volume of normal saline. The overall recovery of {sup 99m}Tc was >90% with >99.99% radionuclidic purity and >99% radiochemical purity. The compatibility of the product in the preparation of {sup 99m}Tc labeled formulations such as {sup 99m}Tc-DMSA and {sup 99m}Tc-EC was found to be satisfactory in terms of high labeling yields (>98%). - Highlights: Black-Right-Pointing-Pointer Utility of electrochemical technique to concentrate {sup 99m}Tc obtained from an expired Zr{sup 99}Mo gel generator. Black-Right-Pointing-Pointer Optimization of experimental conditions for quantitative deposition of {sup 99m}Tc. Black-Right-Pointing-Pointer Evaluation of quality features of the concentrated {sup 99m}TcO{sub 4}{sup -} solution for radiopharmaceutical applications.

  17. Formalizing BPEL-TC Through ?-Calculus

    Directory of Open Access Journals (Sweden)

    Preeti Marwaha

    2013-07-01

    Full Text Available WS-BPEL is way to define business processes that interact with external entities through webservice operations using WSDL. We have proposed BPEL-TC, an extension to existing WS-BPEL whichuses temporally customized Web Services (WSDL-TC as a model for process decomposition and assembly.WSDL-TC handles both backward compatible and incompatible changes and also maintains variousversions of the artifacts that results due to changes over time and customizations desired by the users. Inthis paper, we are using pi-calculus to formalize Business Process Execution Language- TemporalCustomization (BPEL-TC process. π -calculus is a model of computation for concurrent systems alongwith changing connectivity of interactive systems. Pi-calculus is an extension of the process algebra CCS,with added mobility to CCS while preserving its algebraic properties.

  18. 205Tl Knight and chemical shift in the high- Tc superconductors Tl 2Ba 2CuO 6, Tl 2CaBa 2Cu 2O 8 and Tl 2Ca 2Ba 2Cu 3O 10

    Science.gov (United States)

    Winzek, N.; Hentsch, F.; Mehring, M.; Mattausch, Hj.; Kremer, R.; Simon, A.

    1990-06-01

    We report on the 205Tl NMR (nuclear magnetic resonance) spectra of the title compounds below and above the superconducting transition temperature Tc. The TlO layer NMR spectra are dominated by chemical shifts corresponding to Tl 3+ with a smaller additional positive Knight shift, whereas a “defect line” of Tl replacing Ca in the two and three layer compounds exhibits a large negative Knight shift, which is attributed to O-holes in the CuO 2 layers.

  19. Soil-to-Rice Transfer of {sup 99}Tc in Paddy Soils Contaminated in Two Different Ways

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yongho; Lim, Kwangmuk; Jun, In; Kim, Byungho; Keum, Dongkwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Rice is one of the most important food crops in the world. All isotopes of technetium (Tc) are radioactive, and the environmentally most important one is {sup 99}Tc because of its very long half-life (2.1x10{sup 5} years) and relatively high {sup 235}U-fission yield. Accordingly, it is one of the critical radionuclides in an environmental impact assessment for radioactive waste disposal. A significant amount of {sup 99}Tc can be released into the atmosphere in a severe reactor accident as was shown in the Chernobyl accident. It is a pure better emitter and thus internal exposure via food consumption may be a primary contributor to the {sup 99}Tc radiation dose to humans. Paddy rice fields can be contaminated with {sup 99}Tc in various ways. In the present study, greenhouse experiments were conducted to investigate the transfer of {sup 99}Tc from four paddy soils contaminated in two different ways. One was to simulate plowing the topsoil after a pre-transplanting deposition of {sup 99}Tc, whereas the other was to simulate a {sup 99}Tc deposition onto the surface water shortly after transplanting. Soil-to-rice transfer of {sup 99}Tc in paddy soils was experimentally investigated for two different scenarios of the paddy-field contamination. It was demonstrated that a post-transplanting deposition of {sup 99}Tc onto the surface water can lead to a much higher transfer than a pre-transplanting deposition followed by plowing. The surface-water concentrations of {sup 99}Tc following the post-transplanting deposition was markedly higher than those following the pre-transplanting deposition, possibly indicating a much higher plant-base uptake of {sup 99}Tc following the post-transplanting deposition. The present results can be referred to in a radiological impact assessment for the contamination of paddy fields with {sup 99}Tc by chronic or acute releases from nuclear facilities.

  20. A kinetic model for 99mTc-DMSA in the rat.

    Science.gov (United States)

    Maneval, D C; D'Argenio, D Z; Wolf, W

    1990-01-01

    A pharmacokinetic model was developed for the renal imaging agent 99mTc-DMSA in anesthetized rats, which incorporated data from serial measurements of blood and urine simultaneously with dynamic images obtained over an 8-h period. Animals which received a 10 mg/kg dose of unlabeled DMSA immediately before 99mTc-DMSA injection had a significantly reduced kidney accumulation and greater urinary elimination of 99mTc than animals which received the radiopharmaceutical alone. The kidney clearance was also significantly lower in rats receiving unlabeled DMSA, but no significant difference was determined between the urine clearance estimates of the two animal groups. Because the increase in the amount eliminated in the urine was not coupled with a significant change in urine clearance, it would appear that unlabeled DMSA saturated the kidney uptake mechanism(s) of 99mTc-DMSA without modifying the urinary clearance process. This interpretation is consistent with the hypothesis that renal handling of 99mTc-DMSA is governed by both glomerular filtration and peritubular capillary uptake. The simultaneous acquisition of blood, urine and non invasive image data allows for a comprehensive and informative model of the physiological disposition of 99mTc-DMSA.

  1. Technetium Removal Using Tc-Goethite Coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    Um, Wooyong; Wang, Guohui; Jung, Hun Bok; Peterson, Reid A.

    2013-11-18

    This report describes the results from laboratory tests performed at Pacific Northwest National Laboratory for the U.S. Department of Energy (DOE) EM-31 Support Program (EMSP) subtask, “Low temperature waste forms coupled with technetium removal using an alternative immobilization process such as Fe(II) treated-goethite precipitation” to increase our understanding of 99Tc long-term stability in goethite mineral form and the process that controls the 99Tc(VII) reduction and removal by the final Fe (oxy)hydroxide forms. The overall objectives of this task were to 1) evaluate the transformation process of Fe (oxy)hydroxide solids to the more crystalline goethite (α-FeOOH) mineral for 99Tc removal and 2) determine the mechanism that limits 99Tc(IV) reoxidation in Fe(II)-treated 99Tc-goethite mineral and 3) evaluate whether there is a long-term 99Tcoxidation state change for Tc sequestered in the iron solids.

  2. Genotoxic effect of radio marked lymphocytes using Tc-99m complexes; Efecto genotoxico del radiomarcado de linfocitos empleando complejos de Tc-99m

    Energy Technology Data Exchange (ETDEWEB)

    Pedraza L, M.; Ferro F, G.; Mendiola C, M.T.; Morales R, P. [Instituto nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    The genotoxic effect of radio marked lymphocytes was evaluated using {sup 99m}-Tc-HMPAO and {sup 99m}-Tc- gentisic acid complexes. With the results of this work it is pretended to contribute to the knowledge of genetic and structural damages that provokes the radiation in the marked lymphocytes. The d, 1-HMPAO was synthesized in laboratory with a yielding of 30 %. The radiochemical purity of the complexes was greater than 85%. Mouse lymphocytes obtained of sanguineous volumes 2 ml were used. The radio marked efficiency of cells was 19.6 {+-} 6.4% and 25.6 {+-} 5.8% for {sup 99m}Tc-HMPAO and {sup 99m} Tc gentisic acid respectively. The genotoxic effect was evaluated using the technique of Unicellular Electrophoresis in Micro gel (Comet assay). The results showed that both {sup 99m} Tc complexes produce genotoxicity due to their capacity to penetrate cells, therefore the Auger and M internal conversion electrons place all their energy obtaining doses of Gray order. (Author)

  3. 99mTc MIBI in neurofibromatosis imaging diagnosis: case report.

    Science.gov (United States)

    Stefănescu, C; Meignan, M; Volkenstein, P; Rusu, V

    1996-01-01

    99mTc MIBI has been shown to accumulate in different cancer cells types, in vitro and malignant tumours in vivo, making evidence of the scintigraphic diagnostic of them. We report two cases of neurofibromatosis type I, which has realised high levels of 99mTc MIBI uptake, primary to all chemo- or radiotherapy. Only certain zones of tumorous localisation have been seen, but a relation with the lesion histology was not really established. In conclusion, 99mTc MIBI scintigraphy may be usefull in the investigation of type I neurofibromatosis.

  4. Etiology of amyloidosis determines myocardial 99mTc-DPD uptake in amyloidotic cardiomyopathy.

    Science.gov (United States)

    Longhi, Simone; Bonfiglioli, Rachele; Obici, Laura; Gagliardi, Christian; Milandri, Agnese; Lorenzini, Massimiliano; Guidalotti, Pier Luigi; Merlini, Giampaolo; Rapezzi, Claudio

    2015-05-01

    Tc-DPD (Tc-3,3-diphosphono-1,2-propanodicarboxylic acid) has a high affinity for transthyretin (TTR)-infiltrated myocardium, allowing a differential diagnosis with light chain cardiac amyloidosis and other nonamyloidotic cardiomyopathies with a hypertrophic phenotype, in which myocardial tracer uptake is low or absent. Myocardial bone tracer uptake in the rarer forms of amyloidosis (eg, apolipoprotein-related) has been rarely studied. We present 4 cases of cardiac amyloidosis that underwent Tc-DPD scintigraphy; myocardial DPD uptake was present in patients with ATTR, wtTTR and apolipoprotein AI and negative in cases with AL and apolipoprotein AII-related disease.

  5. Oxidative Dissolution Potential of Biogenic and Abiogenic TcO2 in Subsurface Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Fredrickson, Jim K.; Zachara, John M.; Plymale, Andrew E.; Heald, Steve M.; McKinley, James P.; Kennedy, David W.; Liu, Chongxuan; Nachimuthu, Ponnusamy

    2009-04-15

    Technetium-99 (Tc) is an important fission product contaminant associated with sites of nuclear fuels reprocessing and geologic nuclear waste disposal. Exhibiting an intermediate redox potential, Tc is highly mobile in its anionic, oxidized state [Tc(VII)O4-]; and less mobile as a poorly soluble oxyhydroxide precipitate [Tc(IV)O2•nH2O] in its reduced state. Here we investigate the potential for oxidation of Tc(IV) that was heterogeneously reduced by reaction with biogenic Fe(II) in two sediments differing in mineralogy and aggregation state (FRC, RG). Both sediments contained Fe(III) and Mn(III/IV) as redox active phases, but FRC also contained mass-dominant Fe-phyllosilicates of different types. Biogenic Tc(IV)O2•nH2O was oxidized in anoxic, but unreduced RG and FRC sediments through redox interaction with Mn(III/IV) oxides. Bioreduction by Shewanella putrefaciens CN32 dissolved Mn(III/IV) oxides and generated biogenic Fe(II) that was reactive with Tc(VII) in heat-killed, bioreduced sediment. Biogenic Fe(II) in the FRC exceeded that in RG by a factor of two. More rapid reduction rates were observed in the RG that had lower biogenic Fe(II), and less particle aggregation. EXAFS measurements indicated that the primary reduction product was a TcO2-like phase in both sediments. Redox product Tc(IV) oxidized rapidly and completely in RG when contacted with air. Oxidation, in contrast, was slow and incomplete in the FRC, in spite of similar molecular speciation to RG. X-ray microprobe, electron microprobe, x-ray absorption spectroscopy, and micro x-ray diffraction were applied to the whole sediment and isolated Tc-contained particles. These analyses revealed that non-oxidizable Tc(IV) in the FRC existed as complexes with octahedral Fe(III) within intra-grain domains of 50-100 µm-sized, Fe-containing micas presumptively identified as celadonite. The markedly slower oxidation rates in FRC as compared to RG were attributed to mass-transfer-limited migration of O2 into

  6. Oxidative dissolution potential of biogenic and abiogenic TcO 2 in subsurface sediments

    Science.gov (United States)

    Fredrickson, James K.; Zachara, John M.; Plymale, Andrew E.; Heald, Steve M.; McKinley, James P.; Kennedy, David W.; Liu, Chongxuan; Nachimuthu, Ponnusamy

    2009-04-01

    Technetium-99 (Tc) is an important fission product contaminant associated with sites of nuclear fuels reprocessing and geologic nuclear waste disposal. Tc is highly mobile in its most oxidized state [Tc(VII)O4-] and less mobile in the reduced form [Tc(IV)O 2· nH 2O]. Here we investigate the potential for oxidation of Tc(IV) that was heterogeneously reduced by reaction with biogenic Fe(II) in two sediments differing in mineralogy and aggregation state; unconsolidated Pliocene-age fluvial sediment from the upper Ringold (RG) Formation at the Hanford Site and a clay-rich saprolite from the Field Research Center (FRC) background site on the Oak Ridge Site. Both sediments contained Fe(III) and Mn(III/IV) as redox active phases, but FRC also contained mass-dominant Fe-phyllosilicates of different types. Shewanella putrefaciens CN32 reduced Mn(III/IV) oxides and generated Fe(II) that was reactive with Tc(VII) in heat-killed, bioreduced sediment. After bioreduction and heat-killing, biogenic Fe(II) in the FRC exceeded that in RG by a factor of two. More rapid reduction rates were observed in the RG that had lower biogenic Fe(II), and less particle aggregation. EXAFS measurements indicated that the primary reduction product was a TcO 2-like phase in both sediments. The biogenic redox product Tc(IV) oxidized rapidly and completely in RG when contacted with air. Oxidation, in contrast, was slow and incomplete in the FRC, in spite of similar molecular scale speciation of Tc compared to RG. X-ray microprobe, electron microprobe, X-ray absorption spectroscopy, and micro X-ray diffraction were applied to the whole sediment and isolated Tc-containing particles. These analyses revealed that non-oxidizable Tc(IV) in the FRC existed as complexes with octahedral Fe(III) within intra-grain domains of 50-100 μm-sized, Fe-containing micas presumptively identified as celadonite. The markedly slower oxidation rates in FRC as compared to RG were attributed to mass

  7. Oxidative dissolution potential of biogenic and abiogenic TcO{sub 2} in subsurface sediments.

    Energy Technology Data Exchange (ETDEWEB)

    Fredrickson, J. K.; Zachara, J. M.; Plymale, A. E.; Heald, S. M.; McKinley, J. P.; Kennedy, D. W.; Liu, C.; Nachimuthu, P. (X-Ray Science Division); ( PSC-USR); (PNNL)

    2009-04-01

    Technetium-99 (Tc) is an important fission product contaminant associated with sites of nuclear fuels reprocessing and geologic nuclear waste disposal. Tc is highly mobile in its most oxidized state [Tc(VII)O{sub 4}{sup -}] and less mobile in the reduced form [Tc(IV)O{sub 2} {center_dot} nH{sub 2}O]. Here we investigate the potential for oxidation of Tc(IV) that was heterogeneously reduced by reaction with biogenic Fe(II) in two sediments differing in mineralogy and aggregation state; unconsolidated Pliocene-age fluvial sediment from the upper Ringold (RG) Formation at the Hanford Site and a clay-rich saprolite from the Field Research Center (FRC) background site on the Oak Ridge Site. Both sediments contained Fe(III) and Mn(III/IV) as redox active phases, but FRC also contained mass-dominant Fe-phyllosilicates of different types. Shewanella putrefaciens CN32 reduced Mn(III/IV) oxides and generated Fe(II) that was reactive with Tc(VII) in heat-killed, bioreduced sediment. After bioreduction and heat-killing, biogenic Fe(II) in the FRC exceeded that in RG by a factor of two. More rapid reduction rates were observed in the RG that had lower biogenic Fe(II), and less particle aggregation. EXAFS measurements indicated that the primary reduction product was a TcO{sub 2}-like phase in both sediments. The biogenic redox product Tc(IV) oxidized rapidly and completely in RG when contacted with air. Oxidation, in contrast, was slow and incomplete in the FRC, in spite of similar molecular scale speciation of Tc compared to RG. X-ray microprobe, electron microprobe, X-ray absorption spectroscopy, and micro X-ray diffraction were applied to the whole sediment and isolated Tc-containing particles. These analyses revealed that non-oxidizable Tc(IV) in the FRC existed as complexes with octahedral Fe(III) within intra-grain domains of 50-100 {micro}m-sized, Fe-containing micas presumptively identified as celadonite. The markedly slower oxidation rates in FRC as compared to RG were

  8. PREFACE: 2014 Joint IMEKO TC1-TC7-TC13 Symposium: Measurement Science Behind Safety and Security

    Science.gov (United States)

    Sousa, João A.; Ribeiro, Álvaro S.; Filipe, Eduarda

    2015-02-01

    The 2014 Joint IMEKO (International Measurement Confederation) TC1-TC7-TC13 Symposium was organized by RELACRE - Portuguese Association of Accredited Laboratories and the Portuguese Society for Metrology, on 3-5 September 2014. The work of this symposium is reported in this volume. The scope of the symposium includes the main topics covered by the above Technical Committees: - TC1 Education and Training in measurement and Instrumentation - TC7 Measurement Science - TC13 Measurements in Biology and Medicine The effort towards excellence of previous events, in this well established series, is maintained. There has been a special focus on measurement science behind safety and security, with the aim of highlighting the interdisciplinary character of measurement science and the importance of metrology in our daily lives. The discussion was introduced by keynote lectures on measurement challenges in biometrics, health monitoring and social sciences, to promote useful interactions with scientists from different disciplines. The Symposium was attended by experts working in these areas from 18 countries, including USA, Japan and China, and provided a useful forum for them to share and exchange their work and ideas. In total over fifty papers are included in the volume, organized according to the presentation sessions. Each paper was independently peer-reviewed by two reviewers from a distinguished international panel. The Symposium was held in Funchal, capital of Madeira Islands, known as the Atlantic Pearl. This wonderful Atlantic archipelago, formed by Madeira and Porto Santo islands, discovered in the 14th century, was chosen to host the 2014 IMEKO TC1-TC7-TC13 Joint Symposium ''Measurement Science behind Safety and Security''. It was the first territory discovered by the Portuguese sailors, when set out to discover a new world, in an epic journey where instrumentation and quality of measurement played a central role in the success of the enterprise, and gave an

  9. Direct 99mTc labeling of monoclonal antibodies: radiolabeling and in vitro stability.

    Science.gov (United States)

    Garron, J Y; Moinereau, M; Pasqualini, R; Saccavini, J C

    1991-01-01

    Direct labeling involves 99mTc binding to different donor groups on the protein, giving multiple binding sites of various affinities resulting in an in vivo instability. The stability has been considerably improved by activating the antibody using a controlled reduction reaction (using 2-aminoethanethiol). This reaction generates sulfhydryl groups, which are known to strongly bind 99mTc. The direct 99mTc antibody labeling method was explored using whole antibodies and fragments. Analytical methods were developed for routine evaluation of radiolabeling yield and in vitro stability. Stable direct antibody labeling with 99mTc requires the generation of sulfhydryl groups, which show high affinity binding sites for 99mTc. Such groups are obtained with 2-aminoethanethiol (AET), which induces the reduction of the intrachain or interchain disulfide bond, with no structural deterioration or any loss of immunobiological activity of the antibody. The development of fast, reliable analytical methods has made possible the qualitative and quantitative assessment of technetium species generated by the radiolabeling process. Labeling stability is determined by competition of the 99mTc-antibody bond with three ligands, Chelex 100 (a metal chelate-type resin), free DTPA solution and 1% HSA solution. Very good 99mTc-antibody stability is obtained with activated IgG (IgGa) and Fab' fragment, which makes these substances possible candidates for immunoscintigraphy use.

  10. Effects of soluble organic complexants and their degradation products on the removal of selected radionuclides from high-level waste. Part 3, Distributions of Sr, Cs, Tc, Pu, and Am onto 33 absorbers from four variations of a 3:1 dilution of Hanford complexant concentrate (CC) simulant: Part 4, The effects of varying dilution ratios on the distributions of Sr, Cs, Tc, Pu, and Am onto 12 absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, S.F. [Sandia National Labs., Albuquerque, NM (United States); Svitra, Z.V.; Bowen, S.M. [Los Alamos National Lab., NM (United States)

    1995-09-01

    Many of the radioactive waste storage tanks at USDOE facilities contain organic compounds that have been degraded by radiolysis and chemical reactions during decades of storage. Objective of this study was to measure effects of soluble organic complexants and their degradation products on sorption of Sr, Cs, Tc, Pu and Am onto 33 absorbers that in the absence of these organic compounds offer high sorption of these elements. The elements were in a generic simulant for Hanford complexant concentrate supernate that initially contained six organic complexants: EDTA, HEDTA, NTA, citrate, gluconate, and iminodiacetate. This simulant was tested as prepared and after gamma-irradiation to approximately 34 Mrads. Two other variations consisted of the unirradiated and irradiated simulants after treatment at 450C and 15,000 psi in a hydrothermal organic-destruction process. These experiments were conducted with a 3:1 water-to-simulant dilution of each of the four simulant variations. To determine effects of varying dilution ratios on the sorption of these five elements from the unirradiated and gamma-irradiated simulants that were not treated with the hydrothermal process, we measured their distribution from a 1:1 dilution, using 1 M NaOH as the diluent, onto the 12 best-performing absorbers. We then measured the sorption of these five elements from solutions having diluent-simulant ratios of 0, 0.5, 2.0, and 3.0 onto the three absorbers that performed best for sorbing Sr, Pu and Am from the 1:1 dilution. For each of 900 element/absorber/solution combinations, we measured distribution coefficients (Kd values) twice for each period for dynamic contact periods of 30 min, 2 h, and 6 h to obtain information about absorber stability and sorption kinetics. The 5400 measured Kd values indicate that the sorption of Sr, Pu, and Am is significantly decreased by the organic complexants in these simulant solutions, whereas the sorption of Cs and Tc is much less affected.

  11. Novel 99mTc labeled σ receptor ligand as a potential tumor imaging agent

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A novel 99mTc labeled complex, [N-[2-((2-oxo-2-(4-(3-phenylpropyl)piperazin-1-yl)ethyl) (2-mercaptoethyl)amino)acetyl]-2-aminoethanethiolato]Technetium(V) oxide (PPPE-MAMA′-99mTcO) ([99mTc]-2) has been designed and prepared based on the integrated approach. The corresponding rhenium complex (PPPE-MAMA′-ReO)(Re-2) has been prepared and characterized. In vitro competition binding assays show moderate affinity of Re-2 towards σ1 and σ2 receptors with Ki values of 8.67 ± 0.07 and 5.71 ± 1.88 μmol, respectively. Planar images obtained at 0.5 h, 4 h, 20 h after I.v. Injection indicate the accumulation of [99mTc]-2 in MCF-7 human breast tumor bearing mice at 20 h. Furthermore, the accumulation of [99mTc]-2 has been inhibited at 20 h after co-injection of [99mTc]-2 plus haloperidol (1 mg/kg). Biodistribution studies of [99mTc]-2 display an in vivo tumor uptake of 0.14% ± 0.01% ID/g at 24 h post I.v. Injection with a tumor/muscle ratio of 6.02 ± 0.87. The above results suggest that [99mTc]-2, derived from a previously published lead compound, retains certain tumor uptake and affinity for σ receptors. [99mTc]-2 may be used as a basis for further structural modifications to develop tumor imaging agents with high affinity for σ receptors.

  12. 99Mo/(99m)Tc separation: an assessment of technology options.

    Science.gov (United States)

    Dash, Ashutosh; Knapp, F F Russ; Pillai, M R A

    2013-02-01

    Several strategies for the effective separation of (99m)Tc from (99)Mo have been developed and validated. Due to the success of column chromatographic separation using acidic alumina coupled with high specific activity fission (99)Mo (F (99)Mo) for production of (99)Mo/(99m)Tc generators, however, most technologies until recently have generated little interest. The reduced availability of F (99)Mo and consequently the shortage of (99)Mo/(99m)Tc column generators in the recent past have resurrected interest in the production of (99)Mo as well as (99m)Tc by alternate routes. Most of these alternative production processes require separation techniques capable of providing clinical grade (99m)Tc from low specific activity (99)Mo or irradiated Mo targets. For this reason there has been renewed interest in alternate separation routes. This paper reviews the reported separation technologies which include column chromatography, solvent extraction, sublimation and gel systems that have been traditionally used for the fabrication of (99)Mo/(99m)Tc generator systems. The comparative advantage, disadvantage, and technical challenges toward adapting the emerging requirements are discussed. New developments such as solid-phase column extraction, electrochemical separation, extraction chromatography, supported liquid membrane (SLM) and thermochromatographic techniques are also being evaluated for their potential application in the changed scenario of providing (99m)Tc from alternate routes. Based on the analysis provided in this review, it appears that some proven separation technologies can be quickly resurrected for the separation of clinical grade (99m)Tc from macroscopic levels of reactor or cyclotron irradiated molybdenum targets. Furthermore, emerging technologies can be developed further to respond to the expected changing modes of (99m)Tc production.

  13. [Autoerotic fatalities in Greater Dusseldorf].

    Science.gov (United States)

    Hartung, Benno; Hellen, Florence; Borchard, Nora; Huckenbeck, Wolfgang

    2011-01-01

    Autoerotic fatalities in the Greater Dusseldorf area correspond to the relevant medicolegal literature. Our results included exclusively young to middle-aged, usually single men who were found dead in their city apartments. Clothing and devices used showed a great variety. Women's or fetish clothing and complex shackling or hanging devices were disproportionately frequent. In most cases, death occurred due to hanging or ligature strangulation. There was no increased incidence of underlying psychiatric disorders. In most of the deceased no or at least no remarkable alcohol intoxication was found. Occasionally, it may be difficult to reliably differentiate autoerotic accidents, accidents occurring in connection with practices of bondage & discipline, dominance & submission (BDSM) from natural death, suicide or homicide.

  14. Assessing microenvironment immunogenicity using tumor specimen exomes: Co-detection of TcR-α/β V(D)J recombinations correlates with PD-1 expression.

    Science.gov (United States)

    Tu, Yaping N; Tong, Wei Lue; Samy, Mohammad D; Yavorski, John M; Kim, Minjung; Blanck, George

    2017-03-03

    T-cell receptor (TcR) recombinations can be recovered from tumor specimen, whole exome (WXS) files. However, it is not yet clear how these recombinations represent lymphocytes or an anti-tumor immune response. Here we report the identification of productive TcR-β recombinations in WXS files representing primary and metastatic melanoma. The recombinations are identifiable in about 20% of the cancer genome atlas melanoma samples. This frequency of detection is lower than the frequency of TcR-α VJ recombinations, consistent with the occurrence of biallelic TcR-α recombinations and possibly consistent with fact that only one junctional recombination is required for TcR-α whereas two recombinations are required to form a TcR-β gene. Nevertheless, the ratio of productive TcR-β to unproductive TcR-β samples, in comparison to the ratio of productive to unproductive TcR-α or TcR-γ positive-samples, is very high. This result indicates that detection of a productive TcR-β VDJ recombination represents a comparatively high standard for potential antigen binding capacity, when employing a tumor specimen exome file for the assessment. Additionally, PD-1 expression and antigen presentation functions correlated with the co-detection of TcR-α and -β recombinations (e.g., p < 0.0004), suggesting that co-detection of TcR-α and -β recombinations represents an anti-melanoma response that has been blunted by the advent of PD-1 expression. We further show that the algorithm for detecting the TcR-β VDJ recombinations is applicable to exome files generated from mouse tissue, thus providing for opportunities to develop empirical paradigms for interpreting the identification of TcR V(D)J recombinations in tissue resident lymphocytes. This article is protected by copyright. All rights reserved.

  15. A {sup 99m}Tc Generator using PZC for (n,{gamma}) {sup 99}Mo

    Energy Technology Data Exchange (ETDEWEB)

    Adang, H.G.; Mutalib, A.; Suparman, I.; Hamid; Purwadi, B.; Pancoko, M.; Setiowati, S.; Yulianti, V.; Robertus, D.H. [Radioisotope Production Center, National Atomic Energy Agency Kawasan PUSPIPTEK, Serpong (Indonesia)

    1998-10-01

    The high performance adsorbent Poly Zirconium Compound (PZC) was produced by Department of Radioisotope, Japan Atomic Energy Research Institute. This compound was developed as an adsorbent for natural Mo (n,{gamma}) {sup 99}Mo-{sup 99m}Tc Generator. In the present paper, we report the performance of the PZC for a {sup 99m}Tc Generator which was focused on the yield, on elution profile and {sup 99}Mo breakthrough. (author)

  16. Tc-99m-labeled red blood cells for the measurement of red cell mass in newborn infants: concise communication

    Energy Technology Data Exchange (ETDEWEB)

    Linderkamp, O.; Betke, K.; Fendel, H.; Klemm, J.; Lorenzen, K.; Riegel, K.P.

    1980-07-01

    In vitro and in vivo investigations were performed to examine the binding of Tc-99m to neonatal red blood cells (RBC). Labeling efficiency was about 90%, and unbound Tc-99m less than 3% after one washing, in premature and full-term newborns and in children. Thus presence of high percentages of fetal hemoglobin (Hb F) did not influence the labeling of RBCs with Tc-99m. RBCs of 11 newborns were hemolysed and the distribution of Tc-99m on RBC components was analyzed. Although Hb F percentage averaged (60.0 +- 8.10)% (s.d.), only (11.9 +- 3.7)% of Tc-99m was bound by Hb F, whereas (45.0 +- 6.1)% was associated with Hb A. RBC membranes bound (13.7 +- 4.3)% and (29.3 +- 4.0)% were found unbound in hemolysates. These results indicate that Tc-99m preferentially binds to beta chains. In vivo equilibration of Tc-99m RBCs and of albumin labeled with Evans blue was investigated in five newborn infants. Tc-99m RBCs were stable in each case during the first hour after injection. Elution of Tc-99m from RBCs was (3.4 +- 1.5)% per h. Body-to-venous hematocrit ratio averaged 0.86 +- 0.03.

  17. Insights into Stabilization of the 99TcVO Core for Synthesis of 99TcVO Compounds

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, Donna; Burton-Pye, Benjamin P.; Lukens, Wayne W.; Howell, Robertha C.; Francesconi, Lynn C.

    2014-01-01

    Synthesis of technetium-99 (99Tc; t1/2: 2.1 105 years, max: 253 keV) materials is of importance in studies of the nuclear fuel cycle where Tc is a major fission product (6percent thermal yield from 235U and 239Pu), in understanding radioactive tank waste composition, and in identifying 99mTc compounds for nuclear medicine imaging. One of the most useful synthetic starting materials, (NBu4)TcOCl4, is susceptible to disproportionation in water to form TcO4 and TcIV species, especially TcO2 2H2O. This unwanted reaction is especially problematic when working with ligands bearing hard donor atoms, such as oxygen, where the stability with the soft TcV=O3+ core may be low. Polyoxometalates (POMs) are such ligands. They possess defect sites with four hard oxygen atoms and show low (ca. 108) stability constants with transition metals. Tc complexes of POMs are molecular-level models for Tc metal oxide solid-state materials and can provide information on coordination and redox environments of metal oxides that stabilize low-valent Tc. In order to synthesize pure Tc POM complexes [TcVO(1-P2W17O61)]7 (TcVO-1) and [TcVO(2-P2W17O61)]7 (TcVO-2) from (NBu4)TcOCl4, we have identified strategies that minimize formation of TcIV species and optimize the formation of pure TcV species. The parameters that we consider are the amount of ethylene glycol, which is employed as a transfer ligand to prevent hydrolysis of (NBu4)TcOCl4, and the precipitating agent. The TcIV species that contaminates the non-optimized syntheses is likely a TcIV -oxido-bridged dimer [TcIV-(-O)2-TcIV]. We also employ a novel procedure where the 2 ligand is photoactivated and reduced (in the presence of a sacrificial electron donor) to subsequently reduce TcVIIO4 to an isolatable TcVO-2 product that is remarkably free of TcIV.

  18. Synthesis, biodistribution and imaging of {sup 99m}tc-7-HYNIC-TAXOL

    Energy Technology Data Exchange (ETDEWEB)

    Rha, D. S.; Park, J. Y.; Awh, O. D. [College of Health Science, Yonsei University, Seoul (Korea, Republic of); Lee, T. S.; Choi, T. H.; Woo, K. S.; Chung, W. S.; Choi, C. W.; Kim, S. M. [Korea Institutes of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2005-07-01

    Taxol has been used in the treatment of breast, ovary and lung cancers. To evaluate the feasibility of 99mTc-7-HYNIC(hydrazino nicotinamide)-taxol as a tumor imaging agent, it was synthesized, and its biodistribution and gamma camera image were obtained in B16-F10 melanoma bearing C57BL6 mice 7-t-BOC-HYNIC-taxol was synthesized through six steps, and 7-HYNIC-taxol was finally obtained by t-BOC deprotecting from 7-t-BOC-HYNIC-taxol. The product was purified by column chromatography. 99mTc-7-HYNIC-taxol complex from 7-HYNIC-taxol was prepared by labeling with 99mTc in the presence of SnCl2{center_dot}2H20 and tricine. The biochemical behaviors of the complex such as in vitro stability and lipophilicity, in vitro transchelation were investigated. The biodistribution and in vivo image of 99mTc-7-HYNIC-taxol were obtained in B16-F10 melanoma bearing C57BL6 mice. After 1, 6 and 24 hr post-injection, the weight and radioactivity of each organ were measured and gamma camera image was obtained. The total synthetic yield of 7-HYNIC-taxol was 42.6%. Radiolabeling yield of 99mTc-HYNIC-taxol was 99.9%. 99mTc-7-HYNIC-taxol was stable at 37? for 24 hrs. 99mTc-7-HYNIC-taxol was slightly more soluble in water than in organic solvent. The binding ability of 99mTc-7-HYNIC-taxol to serum proteins was 39.9%. In vivo transchelation test, the 99mTc-7-HYNIC-taxol retained over 86% of radiochemical purity after incubation with DTPA or cysteine. 99mTc-7-HYNIC-taxol was intravenously administered to C57BL6 mice bearing B16-F10 melanoma at footpad. Tumor/blood ratios were 1.17, 26.0, and 2.87, and tumor/muscle ratios were 12.2, 168, and 15.0 at 1 h. 6 h and 24 h post injection, respectively. The gamma camera image was obtained at 6 h post injection showed selectively localized in tumor. 99mTc-7-HYNIC-taxol showed high stability and was selectively localized in B16-F10 melanoma. These results suggest that 99mTc-7-HYNIC-taxol can be used as tumor imaging agent.

  19. /sup 99m/Tc-aprotinin: A new tracer for kidney morphology and function

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, C.; Donadio, C.; Tramonti, G.; Lorusso, P.; Bellitto, L.; Lunghi, F.

    1984-01-01

    Aprotinin (Ap), a low molecular weight polyeptide (6500 dalton), is a protease inhibitor which is electively and stably accumulated in the kidney. In 112 adult patients, with either uni- or bilateral renal disease with different degrees of renal impairment (from normal GFR to advanced renal failure), renal scans were performed by means of Ap labelled with /sup 99m/Tc. Highly satisfactory renal scans were obtained in all patients. In 20 patients with renal failure (serum creatinine 1.8 - 8.5 mg/dl, mean 4.7) a comparison was made of the renal scans obtained with /sup 99m/Tc-Ap and with /sup 99m/Tc-DMSA. /sup 99m/Tc-Ap was slightly better than /sup 99m/Tc-DMSA, especially in patients with far advanced renal failure. Some aspects of the pharmacokinetics of /sup 99m/Tc-Ap were studied in 72 cases. In 22 of these patients plasma clearance of /sup 99m/Tc-Ap was determined by the single injection method using a two-compartment model. In patients with GFR>90 ml/min plasma cl of /sup 99m/Tc-Ap was 67.6 +- 8.4 SD ml/min. A good correlation was observed between plasma clearance of /sup 99m/Tc-Ap and GFR (r = 0.74). After i.v. injection /sup 99m/Tc-Ap was stably fixed by the kidney. Renal radioactivity remained stable between the 2nd and the 8th hour after the injection. Urinary excretion of radioactivity measured in 35 patients in the first and in the second 2-hour interval after i.v. injection of /sup 99m/Tc-Ap was negligible in all patients (2.7 +- 1.5 SD percent of the dose in the fist 2 hours; 2.8 +- 1.4 SD between the 2nd and the 4th hour). Conclusions. /sup 99m/Tc-Ap is an excellent agent for renal imaging. It also seems promising for renal function studies.

  20. Power Systems Development Facility Gasification Test Campaing TC18

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2005-08-31

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device (PCD), advanced syngas cleanup systems, and high pressure solids handling systems. This report details Test Campaign TC18 of the PSDF gasification process. Test campaign TC18 began on June 23, 2005, and ended on August 22, 2005, with the gasifier train accumulating 1,342 hours of operation using Powder River Basin (PRB) subbituminous coal. Some of the testing conducted included commissioning of a new recycle syngas compressor for gasifier aeration, evaluation of PCD filter elements and failsafes, testing of gas cleanup technologies, and further evaluation of solids handling equipment. At the conclusion of TC18, the PSDF gasification process had been operated for more than 7,750 hours.

  1. Power Systems Development Facility Gasification Test Campaign TC24

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2008-03-30

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC24, the first test campaign using a bituminous coal as the feedstock in the modified Transport Gasifier configuration. TC24 was conducted from February 16, 2008, through March 19, 2008. The PSDF gasification process operated for about 230 hours in air-blown gasification mode with about 225 tons of Utah bituminous coal feed. Operational challenges in gasifier operation were related to particle agglomeration, a large percentage of oversize coal particles, low overall gasifier solids collection efficiency, and refractory degradation in the gasifier solids collection unit. The carbon conversion and syngas heating values varied widely, with low values obtained during periods of low gasifier operating temperature. Despite the operating difficulties, several periods of steady state operation were achieved, which provided useful data for future testing. TC24 operation afforded the opportunity for testing of various types of technologies, including dry coal feeding with a developmental feeder, the Pressure Decoupled Advanced Coal (PDAC) feeder; evaluating a new hot gas filter element media configuration; and enhancing syngas cleanup with water-gas shift catalysts. During TC24, the PSDF site was also made available for testing of the National Energy Technology Laboratory's fuel cell module and Media Process Technology's hydrogen selective membrane.

  2. Synthesis and evaluation of {sup 99m}Tc/{sup 99}Tc-MAG3-biotin conjugates for antibody pretargeting strategies

    Energy Technology Data Exchange (ETDEWEB)

    Gog, Frank B. van; Visser, Gerard W.M.; Gowrising, Radjish W.A.; Snow, Gordon B.; Dongen, Guus A.M.S. van E-mail: gams.vandongen@azvu.nl

    1998-10-01

    Four {sup 99m}Tc-MAG3-biotin conjugates were synthesized to determine their potential use in antibody pretargeting strategies for radioimmunoscintigraphy (RIS). To use these {sup 99m}Tc-MAG3-biotin conjugates as model compounds for {sup 186}Re-MAG3-biotin conjugates for radioimmunotherapy (RIT), nanomolar amounts of {sup 99}Tc were added as carrier to {sup 99m}Tc. The biotin derivatives used for the preparation of the conjugates - biocytin, biotin hydrazide, biotinyl-piperazine, and biotinyl-diaminosuccinic acid - differed at the site that is regarded to be susceptible to hydrolysis by biotinidase present in human plasma. All four conjugates were produced with high radiochemical purity, were stable in PBS, and demonstrated full binding capacity to streptavidin. The {sup 99m}Tc/{sup 99}Tc-MAG3-labeled biotinyl-piperazine and biotinyl-diaminosuccinic acid conjugates were stable in mouse as well as human plasma, whereas the corresponding biocytin and biotin hydrazide conjugates were rapidly degraded. The biodistribution in nude mice at 30 min after injection was similar for all conjugates, and a rapid blood clearance and high intestinal excretion were both observed. It is concluded that the metabolic routing of a conjugate containing biotin and MAG3 is dominated by these two moieties. For this reason, MAG3-biotin conjugates do not seem suited for pretargeted RIT, for which quantitative and fast renal excretion is a prerequisite to minimize radiation toxicity. However, in a pretargeted RIS approach the {sup 99m}Tc-MAG3-biotin conjugates might have potential.

  3. Tropical Cyclone Prediction Using COAMPS-TC

    Science.gov (United States)

    2014-09-01

    Oceanography | Vol. 27, No.3104 S P E C I A L I S S U E O N N AV Y O P E R AT I O N A L M O D E L S Tropical Cyclone Prediction Using COAMPS...Ocean/ Atmosphere Mesoscale Prediction System for Tropical Cyclones (COAMPS®-TC) has been developed for prediction of tropical cyclone track, structure...and intensity. The COAMPS-TC has been tested in real time in both uncoupled and coupled modes over the past several tropical cyclone seasons in

  4. Synthesis and biological assessment of folate-accepted developer (99m)Tc-DTPA-folate-polymer.

    Science.gov (United States)

    Chen, Fei; Shao, Kejing; Zhu, Bao; Jiang, Mengjun

    2016-05-15

    A novel cancer-targetable folate-poly(2-hydroxyethyl methacrylate) (PFDH) copolymer containing DTPA segment was prepared by conventional chemical synthesis and labeled with (99m)Tc subsequently. The (99m)Tc-labled PFDH could be produced easily with high radiochemical yield of 91% and radiochemical purity of 95%. The LogP octanol-water value for the (99m)Tc-labled PFDH was -2.19 and the radiotracer was stable in phosphate-buffered saline and human serum for 2h (>95% in PBS or ∼90% in human serum). To investigate (99m)Tc-labled PFDH tumor targeting, the in vitro and in vivo stability, cell uptake, in vivo biodistribution, and SPECT imaging were evaluated, respectively. These preliminary results strongly suggest that the novel folate conjugated dendrimer maybe developed to be potential for delivery of therapeutic radionuclides.

  5. Limitations and pitfalls of 99mTc-EDDA/HYNIC-TOC (Tektrotyd) scintigraphy.

    Science.gov (United States)

    Garai, Ildikó; Barna, Sandor; Nagy, Gabor; Forgacs, Attila

    2016-01-01

    Tektrotyd kit was developed by Polatom company for 99mTc labeling to make an alternative tracer of somatostatin receptor scintigraphy available. Since 2005, 99mTc-EDDA/HYNIC-Tyr3-Octreotide has been used in clinical imaging and achieved high impact in management of patients with neuroendocrine tumors. Knowing the limitations and pitfalls is essential to provide ac-curate diagnosis. Therefore, the potential pitfalls associated with the use of 99mTc-EDDA/HYNIC-TOC are reviewed on the basis of own experience. Data were analyzed of 310 patients who underwent somatostatin receptor scintigraphy with 99mTc-Tektrotyd. Pitfalls during radiolabeling process or acquisition can worsen the sensitivity of SRS (somatostatin receptor scintigraphy). Recognizing physi-ological and clinical pitfalls, the diagnostic accuracy will improve.

  6. A {sup 99m}Tc-labeled dual-domain cytokine ligand for imaging of inflammation

    Energy Technology Data Exchange (ETDEWEB)

    Liu Zhonglin, E-mail: zliu@radiology.arizona.edu [Department of Radiology, University of Arizona, Tucson, P.O. Box 245067 Tucson, AZ 85724-5067 (United States); Wyffels, Leonie; Barber, Christy [Department of Radiology, University of Arizona, Tucson, P.O. Box 245067 Tucson, AZ 85724-5067 (United States); Hui, Mizhou M. [AmProtein, Inc. San Gabriel, CA (United States); Woolfenden, James M. [Department of Radiology, University of Arizona, Tucson, P.O. Box 245067 Tucson, AZ 85724-5067 (United States)

    2011-08-15

    Introduction: Interleukin (IL)-1 and IL-18 are potent proinflammatory cytokines in inflammation-related diseases. Their actions are regulated by IL-1 receptor antagonist (IL-1ra) and IL-18 binding protein (IL-18bp). This study was designed to {sup 99m}Tc-radiolabel an IL-1ra and IL-18bp dual-domain cytokine ligand, IL-18bp-Fc-IL-1ra, for specific inflammation targeting. Methods: The {sup 99m}Tc-IL-18bp-Fc-IL-1ra was obtained by direct labeling via 2-iminothiolane reduction. Competitive binding of {sup 99m}Tc-labeled and unlabeled IL-18bp-Fc-IL-1ra to rat polymorphonuclear leukocytes was assessed in vitro. A mouse ear edema model was used to evaluate specific targeting properties of {sup 99m}Tc-IL-18bp-Fc-IL1ra in vivo. The correlation between {sup 99m}Tc-IL-18bp-Fc-IL-1ra uptake and {sup 111}In-labeled polymorphonuclear neutrophil infiltration was studied using ischemic-reperfused rat hearts. Results: Direct {sup 99m}Tc-labeling yielded a stable dual-domain cytokine radioligand with radiochemical purity greater than 95% after gel filtration. Competitive binding studies showed specific targeting of {sup 99m}Tc-IL-18bp-Fc-IL-1ra to inflammatory cells. The {sup 99m}Tc-IL-18bp-Fc-IL-1ra uptake was 1.80{+-}0.17 % injected dose per gram (%ID/g) in the inflamed ear without blocking, whereas uptake in the presence of IL-18bp-Fc-IL-1ra was 1.09{+-}0.08 %ID/g (P<.05). The amounts of IL-1{beta} and IL-18 were significantly increased in the inflamed ears compared to the vehicle controls. A significant correlation of {sup 99m}Tc-IL-18bp-Fc-IL-1ra with {sup 111}In-labeled neutrophil distribution was observed in the ischemic-reperfused hearts (P<.001). Conclusion: Targeting proinflammatory cytokines with {sup 99m}Tc-IL-18bp-Fc-IL-1ra may provide a suitable approach for specific detection of inflammatory sites.

  7. Investigating the role of 99mTc-TRODAT-1 SPECT imaging in idiopathic Parkinson's disease

    Institute of Scientific and Technical Information of China (English)

    GENG Yu; SHI Guo-hua; JIANG Yun; XU Ling-xun; HU Xing-yue; SHAO Yu-quan

    2005-01-01

    Objective: To investigate the role of 99mTc-TRODAT-1 SPECT in diagnosis and assessing severity of idiopathic Parkinson's disease (PD). Methods: Thirty-eight patients with primary, tentative diagnosis of PD and eighteen age-matched normal controls were studied with 99mTc-TRODAT-1 SPECT imaging. The regions of interests (ROIs) were drawn manually on cerebellum (CB), occipital cortex (OC) and three transverse plane slice-views of striatums, the semiquantitative BG (background)/[(OC+CB)/2] were then calculated. Results: A lower uptake of 99mTc-TRODAT-Ⅰ in striatums were displayed in thirty-six out of thirty-eight PD patients by visual inspection, compared to controls. In twenty-four PD cases with HYS (Hoehn and Yahr scale) stage I, a greater loss of DAT uptake was found in striatum and its subregions contralateral striatum to the affected limbs than in the same regions of the controls, although the striatal uptake was bilaterally reduced. Using Spearman correlation analysis showed that the reduction of the uptake ratios significantly correlated with the UPDRS in striatum and all its subregions in the PD group (P<0.05), a similar change was also found in the putamen by using the rating scale of Hoehn and Yahr (P<0.05).However, analysis of variance (ANOVA) did not show any relationship between the decreasing uptake of 99mTc-TRODAT-1 and increasing severity of PD patients, although the specific uptake of 99mTc-TRODAT-Ⅰ was continuously decreased in the striatum by visual inspection with the progress of PD from HYS stage Ⅰ to Ⅲ. Conclusion: 99mTc-TRODAT- 1 SPECT imaging may serve as a useful method for improving the correct diagnosis of PD. In assessing the role of99mTc-TRODAT- 1 SPECT in disease severity of PD, UPDRS can offer a comprehensive index, although the Hoehn and Yahr assessment may be available in part.

  8. Greater trochanteric fracture with occult intertrochanteric extension.

    Science.gov (United States)

    Reiter, Michael; O'Brien, Seth D; Bui-Mansfield, Liem T; Alderete, Joseph

    2013-10-01

    Proximal femoral fractures are frequently encountered in the emergency department (ED). Prompt diagnosis is paramount as delay will exacerbate the already poor outcomes associated with these injuries. In cases where radiography is negative but clinical suspicion remains high, magnetic resonance imaging (MRI) is the study of choice as it has the capability to depict fractures which are occult on other imaging modalities. Awareness of a particular subset of proximal femoral fractures, namely greater trochanteric fractures, is vital for both radiologists and clinicians since it has been well documented that they invariably have an intertrochanteric component which may require surgical management. The detection of intertrochanteric or cervical extension of greater trochanteric fractures has been described utilizing MRI but is underestimated with both computed tomography (CT) and bone scan. Therefore, if MRI is unavailable or contraindicated, the diagnosis of an isolated greater trochanteric fracture should be met with caution. The importance of avoiding this potential pitfall is demonstrated in the following case of an elderly woman with hip pain and CT demonstrating an isolated greater trochanteric fracture who subsequently returned to the ED with a displaced intertrochanteric fracture.

  9. Comparative analysis of the recently discovered hAT transposon TcBuster in human cells.

    Directory of Open Access Journals (Sweden)

    Lauren E Woodard

    Full Text Available BACKGROUND: Transposons are useful tools for creating transgenic organisms, insertional mutagenesis, and genome engineering. TcBuster, a novel hAT-family transposon system derived from the red flour beetle Tribolium castaneum, was shown to be highly active in previous studies in insect embryoes. METHODOLOGY/PRINCIPAL FINDINGS: We tested TcBuster for its activity in human embryonic kidney 293 (HEK-293 cells. Excision footprints obtained from HEK-293 cells contained small insertions and deletions consistent with a hAT-type repair mechanism of hairpin formation and non-homologous end-joining. Genome-wide analysis of 23,417 piggyBac, 30,303 Sleeping Beauty, and 27,985 TcBuster integrations in HEK-293 cells revealed a uniquely different integration pattern when compared to other transposon systems with regards to genomic elements. TcBuster experimental conditions were optimized to assay TcBuster activity in HEK-293 cells by colony assay selection for a neomycin-containing transposon. Increasing transposon plasmid increased the number of colonies, whereas gene transfer activity dependent on codon-optimized transposase plasmid peaked at 100 ng with decreased colonies at the highest doses of transposase DNA. Expression of the related human proteins Buster1, Buster3, and SCAND3 in HEK-293 cells did not result in genomic integration of the TcBuster transposon. TcBuster, Tol2, and piggyBac were compared directly at different ratios of transposon to transposase and found to be approximately comparable while having their own ratio preferences. CONCLUSIONS/SIGNIFICANCE: TcBuster was found to be highly active in mammalian HEK-293 cells and represents a promising tool for mammalian genome engineering.

  10. Jasmonate-responsive expression of paclitaxel biosynthesis genes in Taxus cuspidata cultured cells is negatively regulated by the bHLH transcription factors TcJAMYC1, TcJAMYC2 and TcJAMYC4

    Directory of Open Access Journals (Sweden)

    Sangram Keshari Lenka

    2015-02-01

    Full Text Available Taxus cell suspension culture is a sustainable technology for the industrial production of paclitaxel (Taxol®, a highly modified diterpene anti-cancer agent. The methyl jasmonate (MJ-mediated paclitaxel biosynthetic pathway is not fully characterized, making metabolic engineering efforts difficult. Here, promoters of seven genes (TASY, T5αH, DBAT, DBBT, PAM, BAPT and DBTNBT, encoding enzymes of the paclitaxel biosynthetic pathway were isolated and used to drive MJ-inducible expression of a GUS reporter construct in transiently transformed Taxus cells, showing that elicitation of paclitaxel production by MJ is regulated at least in part at the level of transcription. The paclitaxel biosynthetic pathway promoters contained a large number of E-box sites (CANNTG, similar to the binding sites for the key MJ-inducible transcription factor AtMYC2 from Arabidopsis thaliana. Three MJ-inducible MYC transcription factors similar to AtMYC2 (TcJAMYC1, TcJAMYC2 and TcJAMYC4 were identified in Taxus. Transcriptional regulation of paclitaxel biosynthetic pathway promoters by transient over expression of TcJAMYC transcription factors indicated a negative rather than positive regulatory role of TcJAMYCs on paclitaxel biosynthetic gene expression.

  11. Radiolabelling of human platelets with sup 99m Tc-HMPAO

    Energy Technology Data Exchange (ETDEWEB)

    Vorne, M.; Honkanen, T.; Karppinen, K.; Roening, M.; Sakki, S. (Paeijaet-Haeme Central Hospital, Lahti (Finland))

    1989-01-01

    The optimum conditions for labelling platelets with lipophilic {sup 99m}Tc-hexamethyl propylene amine oxime ({sup 99m}Tc-HMPAO) were evaluated. An aseptic closed system was used throughout the procedure in patient studies. 48 ml blood were withdrawn into 12 ml ACD using sterile 60 ml plastic syringes. After mixing, the blood was transferred to sterile 10 ml vacuum tubes and platelets were isolated according to standard centrifugation procedures. The labelling efficiency was not dependent upon incubation temperature (22 deg. C, 37 deg. C) but was greater in saline than in the presence of plasma. The labelling efficiency increased with time up to 60 min in saline. The elution of {sup 99m}Tc from platelets was about 25% in plasma milieu in vitro but did not increase with time during 160 min. 5 patients with verified fresh deep vein thrombosis in the lower leg were imaged after injection of labelled autologous platelets. All 4 of the patients without anticoagulant therapy showed positive uptake of {sup 99m}Tc-HMPAO-labelled platelets, but the 5th patient - under heparin therapy - was negative in scientigraphy. Our results are encouraging and {sup 99m}Tc-HMPAO-labelled platelets offer a promising tool for evaluating various clinical situations. (author).

  12. Role of CD8 Regulatory T Cells versus Tc1 and Tc17 Cells in the Development of Human Graft-versus-Host Disease

    Science.gov (United States)

    Gutiérrez-Hoya, Adriana; López-Santiago, Rubén; Vela-Ojeda, Jorge; Montiel-Cervantes, Laura; Rodríguez-Cortés, Octavio; Rosales-García, Víctor; Flores-Mejía, Raúl; Sandoval-Borrego, Daniela

    2017-01-01

    CD8+ T cells that secrete proinflammatory cytokines play a central role in exacerbation of inflammation; however, a new subpopulation of CD8 regulatory T cells has recently been characterized. This study analyzes the prominent role of these different subpopulations in the development of graft-versus-host disease (GVHD). Samples from 8 healthy donors mobilized with Filgrastim® (G-CSF) and 18 patients who underwent allogeneic hematopoietic stem cell transplantation (HSCT) were evaluated by flow cytometry. Mobilization induced an increase in Tc1 (p < 0.01), Th1 (p < 0.001), Tc17 (p < 0.05), and CD8+IL-10+ cells (p < 0.05), showing that G-CSF induces both pro- and anti-inflammatory profiles. Donor-patient correlation revealed a trend (p = 0.06) toward the development of GVHD in patients who receive a high percentage of Tc1 cells. Patients with acute GVHD (aGVHD), either active or controlled, and patients without GVHD were evaluated; patients with active aGVHD had a higher percentage of Tc1 (p < 0.01) and Tc17 (p < 0.05) cells, as opposed to patients without GVHD in whom a higher percentage of CD8 Treg cells (p < 0.01) was found. These findings indicate that the increase in Tc1 and Tc17 cells is associated with GVHD development, while regulatory CD8 T cells might have a protective role in this disease. These tests can be used to monitor and control GVHD. PMID:28164135

  13. Role of CD8 Regulatory T Cells versus Tc1 and Tc17 Cells in the Development of Human Graft-versus-Host Disease

    Directory of Open Access Journals (Sweden)

    Adriana Gutiérrez-Hoya

    2017-01-01

    Full Text Available CD8+ T cells that secrete proinflammatory cytokines play a central role in exacerbation of inflammation; however, a new subpopulation of CD8 regulatory T cells has recently been characterized. This study analyzes the prominent role of these different subpopulations in the development of graft-versus-host disease (GVHD. Samples from 8 healthy donors mobilized with Filgrastim® (G-CSF and 18 patients who underwent allogeneic hematopoietic stem cell transplantation (HSCT were evaluated by flow cytometry. Mobilization induced an increase in Tc1 (p<0.01, Th1 (p<0.001, Tc17 (p<0.05, and CD8+IL-10+ cells (p<0.05, showing that G-CSF induces both pro- and anti-inflammatory profiles. Donor-patient correlation revealed a trend (p=0.06 toward the development of GVHD in patients who receive a high percentage of Tc1 cells. Patients with acute GVHD (aGVHD, either active or controlled, and patients without GVHD were evaluated; patients with active aGVHD had a higher percentage of Tc1 (p<0.01 and Tc17 (p<0.05 cells, as opposed to patients without GVHD in whom a higher percentage of CD8 Treg cells (p<0.01 was found. These findings indicate that the increase in Tc1 and Tc17 cells is associated with GVHD development, while regulatory CD8 T cells might have a protective role in this disease. These tests can be used to monitor and control GVHD.

  14. A fast and simple dose-calibrator-based quality control test for the radionuclidic purity of cyclotron-produced 99mTc

    Science.gov (United States)

    Tanguay, J.; Hou, X.; Esquinas, P.; Vuckovic, M.; Buckley, K.; Schaffer, P.; Bénard, F.; Ruth, T. J.; Celler, A.

    2015-11-01

    Cyclotron production of {{}99\\text{m}} Tc through the 100Mo(p,2n){{}99\\text{m}} Tc reaction channel is actively being investigated as an alternative to reactor-based 99Mo generation by nuclear fission of 235U. Like most radioisotope production methods, cyclotron production of {{}99\\text{m}} Tc will result in creation of unwanted impurities, including Tc and non-Tc isotopes. It is important to measure the amounts of these impurities for release of cyclotron-produced {{}99\\text{m}} Tc (CPTc) for clinical use. Detection of radioactive impurities will rely on measurements of their gamma (γ) emissions. Gamma spectroscopy is not suitable for this purpose because the overwhelming presence of {{}99\\text{m}} Tc and the count-rate limitations of γ spectroscopy systems preclude fast and accurate measurement of small amounts of impurities. In this article we describe a simple and fast method for measuring γ emission rates from radioactive impurities in CPTc. The proposed method is similar to that used to identify 99Mo breakthrough in generator-produced {{}99\\text{m}} Tc: one dose calibrator (DC) reading of a CPTc source placed in a lead shield is followed by a second reading of the same source in air. Our experimental and theoretical analysis show that the ratio of DC readings in lead to those in air are linearly related to γ emission rates from impurities per MBq of {{}99\\text{m}} Tc over a large range of clinically-relevant production conditions. We show that estimates of the γ emission rates from Tc impurities per MBq of {{}99\\text{m}} Tc can be used to estimate increases in radiation dose (relative to pure {{}99\\text{m}} Tc) to patients injected with CPTc-based radiopharmaceuticals. This enables establishing dosimetry-based clinical-release criteria that can be tested using commercially-available dose calibrators. We show that our approach is highly sensitive to the presence of {{}93\\text{g}} Tc, {{}93\\text{m}} Tc, {{}94\\text{g}} Tc, {{}94\\text{m}} Tc

  15. General report of TC 106: Unsaturated soils

    NARCIS (Netherlands)

    Jommi, C.

    2013-01-01

    This general report summarises the contributions on unsaturated soil mechanics submitted to the Discussion Session of TC106 – Unsaturated soils –at the 18th International Conference on Soil Mechanics and Geotechnical Engineering held in Paris in September 2013. The thirty-five papers collected under

  16. General report of TC 106: Unsaturated soils

    NARCIS (Netherlands)

    Jommi, C.

    2013-01-01

    This general report summarises the contributions on unsaturated soil mechanics submitted to the Discussion Session of TC106 – Unsaturated soils –at the 18th International Conference on Soil Mechanics and Geotechnical Engineering held in Paris in September 2013. The thirty-five papers collected under

  17. The Relationship Between the High-Tc Superconductivity of Oxide and the Number of Average Valence Electrons%高Tc氧化物超导电性与平均价电子数关系

    Institute of Scientific and Technical Information of China (English)

    谭勇权

    2001-01-01

    自Villars等人首先尝试用黄金坐标对高Tc(氧化物超导体的临界温度)超导电性进行分析以来,此法一直为研究人员所重视,本文亦用此法对近百种高Tc氧化物超导体进行分析,得出高Tc氧化物超导电性的又一新的经验判据:一切高Tc氧化物超导体其平均价电子数都在3.9至6.6之间,其值不在此范围内的氧化物都不具有高Tc超导电性.

  18. Development of Tyrosine-Based Radiotracer Tc99m-N4-Tyrosine for Breast Cancer Imaging

    Directory of Open Access Journals (Sweden)

    Fan-Lin Kong

    2012-01-01

    Full Text Available The purpose of this study was to develop an efficient way to synthesize Tc99m-O-[3-(1,4,8,11-tetraazabicyclohexadecane-propyl]-tyrosine (Tc99m-N4-Tyrosine, a novel amino acid-based radiotracer, and evaluate its potential in breast cancer gamma imaging. Precursor N4-Tyrosine was synthesized using a 5-step procedure, and its total synthesis yield was 38%. It was successfully labeled with Tc99m with high radiochemical purity (>95%. Cellular uptake of Tc99m-N4-Tyrosine was much higher than that of Tc99m-N4 and the clinical gold standard 18F-2-deoxy-2-fluoro-glucose (18F-FDG in rat breast tumor cells in vitro. Tissue uptake and dosimetry estimation in normal rats revealed that Tc99m-N4-Tyrosine could be safely administered to humans. Evaluation in breast tumor-bearing rats showed that although Tc99m-N4-Tyrosine appeared to be inferior to 18F-FDG in distinguishing breast tumor tissue from chemical-induced inflammatory tissue, it had high tumor-to-muscle uptake ratios and could detect breast tumors clearly by planar scintigraphic imaging. Tc99m-N4-Tyrosine could thus be a useful radiotracer for use in breast tumor diagnostic imaging.

  19. High-Tc Superconductivity and Raman Scattering Study of the phonon properties of electron doped (transition metal, rare-earth) - Oxygen-Free CaFeAsF and compared with RFeAsO system

    Science.gov (United States)

    Sasmal, Kalyan; Hadjiev, Viktor; Chu, C. W.(Paul)

    Quaternary CaFeAsF has ZrCuSiAs-type structure,(RO)δ+ layer in RFeAsO replaced by (CaF)δ+ layer,with tetragonal (P4/nmm)-orthorhombic (Cmma) phase transition at 134K,while magnetic order,SDW sets in at 114K. Partial replacement of Fe with Co/Ni is direct electron doping to (FeAs)δ+ layer.Tc ~15K in CaFe0.9Ni0.1AsF.Substitution of rare earth metal for alkaline earth metal suppresses anomaly in resistivity & induces superconductivity.Tc ~52K in Ca0.5Pr0.5FeAsF.Characterized by resistivity, susceptibility,XRD & EDX-SEM.Upper critical field estimated from magneto resistance.Bulk superconductivity proved by DC magnetization. Hall coefficient RH revealed hole-like charge carriers in parent compound CaFeAsF, while electron-type (RH in normal state is -Ve) for Ca0.5Pr0.5FeAsF.Evolution of Raman active phonons of Ca1-xPrxFeAsF measured with polarized Raman spectroscopy at room temperature from absurfaces of impurity-free microcrystals.Spectra exhibit sharp phonon lines on very weak electronic scattering background.Frequency and symmetry of Raman phonons involving out-of-plane atomic vibrations are found at 162.5 cm-1 (A1 g, Pr), 201 cm-1 (A1 g, As), 215.5 cm-1 (B1 g, Fe), 265 cm-1 (Eg, Fe) and 334 cm-1 (B1 g, F) for Ca0.5Pr0.5FeAsF.Observations are compared with RFeAsO unconventional superconductors also possibly related to magnetic fluctuations

  20. TC81201F MPEG2 decoder LSI; MPEG2 decoder LSI TC81201F

    Energy Technology Data Exchange (ETDEWEB)

    Kitagaki, K. [Toshiba Corp., Tokyo (Japan)

    1996-04-01

    The moving picture expert group 2 (MPEG2) decoder LSI series have been developed, in order to meet needs for diversifying multi-media systems. MPEG2 is an international standard for coding moving pictures, capable of compressing large quantities of moving picture data. Therefore, the decoder LSI for the MPEG2 signals is also a key device to realize the multi-media systems. The system needs are diversifying, as seen in different audio codes for DVD`s and digital satellite broadcasting systems (DBS`s). The company has developed, based on decoder LSI T9556 announced in 1994, TC81200F for mass production, TC81201F optimized for the DVD system and TC81211F as the one-chip device for MPEG1 decoder. Chip cost and system cost of TC81201F are reduced by optimizing functions and circuits, and by reducing external memories. 4 refs., 4 figs., 1 tab.

  1. Dose calibrator linearity test: 99mTc versus 18F radioisotopes

    Directory of Open Access Journals (Sweden)

    José Willegaignon

    2015-02-01

    Full Text Available Objective: The present study was aimed at evaluating the viability of replacing 18F with 99mTc in dose calibrator linearity testing. Materials and Methods: The test was performed with sources of 99mTc (62 GBq and 18F (12 GBq whose activities were measured up to values lower than 1 MBq. Ratios and deviations between experimental and theoretical 99mTc and 18F sources activities were calculated and subsequently compared. Results: Mean deviations between experimental and theoretical 99mTc and 18F sources activities were 0.56 (± 1.79% and 0.92 (± 1.19%, respectively. The mean ratio between activities indicated by the device for the 99mTc source as measured with the equipment pre-calibrated to measure 99mTc and 18F was 3.42 (± 0.06, and for the 18F source this ratio was 3.39 (± 0.05, values considered constant over the measurement time. Conclusion: The results of the linearity test using 99mTc were compatible with those obtained with the 18F source, indicating the viability of utilizing both radioisotopes in dose calibrator linearity testing. Such information in association with the high potential of radiation exposure and costs involved in 18F acquisition suggest 99mTc as the element of choice to perform dose calibrator linearity tests in centers that use 18F, without any detriment to the procedure as well as to the quality of the nuclear medicine service.

  2. Dose calibrator linearity test: {sup 99m}Tc versus {sup 18}F radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Willegaignon, Jose; Coura-Filho, George Barberio; Garcez, Alexandre Teles, E-mail: willegaignon@hotmail.com [Instituto do Cancer do Estado de Sao Paulo Octavio Frias de Oliveira (ICESP), Sao Paulo, SP (Brazil); Sapienza, Marcelo Tatit; Buchpiguel, Carlos Alberto [Universidade de Sao Paulo (FM/USP), Sao Paulo, SP (Brazil). Fac. de Medicina; Alves, Carlos Eduardo Gonzalez Ribeiro; Cardona, Marissa Anabel Rivera; Gutterres, Ricardo Fraga [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2015-01-15

    Objective: the present study was aimed at evaluating the viability of replacing {sup 18}F with {sup 99m}Tc in dose calibrator linearity testing. Materials and methods: the test was performed with sources of {sup 99m}Tc (62 GBq) and {sup 18}F (12 GBq) whose activities were measured up to values lower than 1 MBq. Ratios and deviations between experimental and theoretical {sup 99m}Tc and {sup 18}F sources activities were calculated and subsequently compared. Results: mean deviations between experimental and theoretical {sup 99m}Tc and {sup 18}F sources activities were 0.56 (± 1.79)% and 0.92 (± 1.19)%, respectively. The mean ratio between activities indicated by the device for the {sup 99m}Tc source as measured with the equipment precalibrated to measure {sup 99m}Tc and {sup 18}F was 3.42 (± 0.06), and for the {sup 18}F source this ratio was 3.39 (± 0.05), values considered constant over the measurement time. Conclusion: the results of the linearity test using {sup 99m}Tc were compatible with those obtained with the {sup 18}F source, indicating the viability of utilizing both radioisotopes in dose calibrator linearity testing. Such information in association with the high potential of radiation exposure and costs involved in {sup 18}F acquisition suggest {sup 99m}Tc as the element of choice to perform dose calibrator linearity tests in centers that use {sup 18}F, without any detriment to the procedure as well as to the quality of the nuclear medicine service. (author)

  3. Water-stable fac-{TcO₃}⁺ complexes - a new field of technetium chemistry.

    Science.gov (United States)

    Braband, Henrik

    2011-01-01

    The development of technetium chemistry has been lagging behind that of its heavier congener rhenium, primarily because the inherent radioactivity of all Tc isotopes has limited the number of laboratories that can study the chemistry of this fascinating element. Although technetium is an artificial element, it is not rare. Significant amounts of the isotope (99)Tc are produced every day as a fission byproduct in nuclear power plants. Therefore, a fundamental understanding of the chemistry of (99)Tc is essential to avoid its release into the environment. In this article the chemistry of technetium at its highest oxidation state (+VII) is reviewed with a special focus on recent developments which make water-stable complexes of the general type [TcO(3)(tacn-R)](+) (tacn-R = 1,4,7-triazacyclononane or derivatives) accessible. Complexes containing the fac-{TcO(3)}(+) core display a unique reactivity. In analogy to [OsO(4)] and [RuO(4)], complexes containing the fac-{TcO(3)}(+) core undergo with alkenes metal-mediated, vicinal cis-dihydroxylation reactions (alkene-glycol interconversion) in water via a (3+2)-cycloaddition reaction. Therefore, water-stable fac-{(99m)TcO(3)}(+) complexes pave the way for a new labeling strategy for radiopharmaceutical applications, based on (3+2)-cycloaddition reactions. This new concept for the labeling of biomolecules with small [(99m)TcO(3)(tacn-R)](+)-type complexes by way of a (3+2)-cycloaddition with alkenes is discussed in detail. The herein reported developments in high-valent technetium chemistry create a new field of research with this artificial element. This demonstrates the potential of fundamental research to provide new impetus of innovation for the development of new methods for radiopharmaceutical applications.

  4. Dose calibrator linearity test: 99mTc versus 18F radioisotopes*

    Science.gov (United States)

    Willegaignon, José; Sapienza, Marcelo Tatit; Coura-Filho, George Barberio; Garcez, Alexandre Teles; Alves, Carlos Eduardo Gonzalez Ribeiro; Cardona, Marissa Anabel Rivera; Gutterres, Ricardo Fraga; Buchpiguel, Carlos Alberto

    2015-01-01

    Objective The present study was aimed at evaluating the viability of replacing 18F with 99mTc in dose calibrator linearity testing. Materials and Methods The test was performed with sources of 99mTc (62 GBq) and 18F (12 GBq) whose activities were measured up to values lower than 1 MBq. Ratios and deviations between experimental and theoretical 99mTc and 18F sources activities were calculated and subsequently compared. Results Mean deviations between experimental and theoretical 99mTc and 18F sources activities were 0.56 (± 1.79)% and 0.92 (± 1.19)%, respectively. The mean ratio between activities indicated by the device for the 99mTc source as measured with the equipment pre-calibrated to measure 99mTc and 18F was 3.42 (± 0.06), and for the 18F source this ratio was 3.39 (± 0.05), values considered constant over the measurement time. Conclusion The results of the linearity test using 99mTc were compatible with those obtained with the 18F source, indicating the viability of utilizing both radioisotopes in dose calibrator linearity testing. Such information in association with the high potential of radiation exposure and costs involved in 18F acquisition suggest 99mTc as the element of choice to perform dose calibrator linearity tests in centers that use 18F, without any detriment to the procedure as well as to the quality of the nuclear medicine service. PMID:25798005

  5. The function of Sn(II)-apatite as a Tc immobilizing agent

    Science.gov (United States)

    Asmussen, R. Matthew; Neeway, James J.; Lawter, Amanda R.; Levitskaia, Tatiana G.; Lukens, Wayne W.; Qafoku, Nikolla P.

    2016-11-01

    At the U.S. Department of Energy Hanford Site, Tc-99 is a component of low-activity waste (LAW) fractions of the nuclear tank waste and removal of Tc from LAW streams would greatly benefit the site remediation process. In this study, we investigated the removal of Tc(VII), as pertechnetate, from deionized water (DIW) and a LAW simulant through batch sorption testing and solid phase characterization using tin (II) apatite (Sn-A) and SnCl2. Sn-A showed higher levels of Tc removal from both DIW and LAW simulant. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/XEDS) and X-ray absorption spectroscopy (XAS) of reacted Sn-A in DIW showed that TcO4- is reduced to Tc(IV) on the Sn-A surface. The performance of Sn-A in the LAW simulant was lowered due to a combined effect of the high alkalinity, which lead to an increased dissolution of Sn from the Sn-A, and a preference for the reduction of Cr(VI).

  6. On the origin of the Almahata-Sitta meteorite and 2008TC3 asteroid

    CERN Document Server

    Gayon-Markt, Julie; Morbidelli, Alessandro; Marchi, Simone

    2012-01-01

    Asteroid 2008TC3 was a Near Earth Asteroid that impacted the Earth on 2008 October 7. Meteorites were produced by the break-up of 2008TC3 in the high atmosphere and at present, about 600 meteorites - called Almahata Sitta - coming from 2008TC3 have been recovered. A mineralogical study of Almahata Sitta fragments shows that the asteroid 2008TC3 was made of meteorites of different types (ureilites, H, L, and E chondrites). Understanding the origin of this body and how it was put together remain a challenge. Here we perform a detailed spectroscopical and dynamical investigation to show that the most likely source region of 2008TC3 is in the inner Main Belt at low inclination (i<8 degrees). We show that asteroids with spectroscopic classes that can be associated with the different meteorite types of Almahata Sitta are present in the region of the Main Belt that includes the Nysa-Polana family and objects of the Background at low inclination. Searching for a possible scenario of formation for 2008TC3, we show ...

  7. Thymidine kinase enzyme selective imaging radiopharmaceutical. {sup 99m}Tc(CO){sub 3}-Ganciclovir

    Energy Technology Data Exchange (ETDEWEB)

    Gedik, B.; Teksoez, S.; Ichedef, C.; Kilcar, A.Y.; Medine, E.I.; Ucar, E. [Ege Univ., Bornova, Izmir (Turkey). Dept. of Nuclear Applications

    2013-03-01

    The aim of this study is to radiolabel Ganciclovir, known as having selective antiviral properties against thymidine kinase, with technetium tricarbonylcore ({sup 99m}Tc(CO){sub 3}{sup +}) and to investigate the biological behavior of this complex in vitro and in vivo. Commercially provided Ganciclovir (GCV) was radiolabeled with {sup 99m}Tc(CO){sub 3}{sup +}. Initially, optimum radiolabeling conditions were determined by analyzing factors such as temperature, pH and time. Quality control of the radiolabeled compound was performed. The radiolabeling yield was found to be 97%. The {sup 99m}Tc(CO){sub 3}-GCV complex also displayed good in vitro stability during the 24 h period. In vitro cell uptake studies showed that the {sup 99m}Tc(CO){sub 3}-GCV complex is highly uptaken in A-549, PC-3, HeLa cell lines according to the control group {sup 99m}Tc(I)-tricarbonyl core. The knowledge gained from in vivo and in vitro studies of {sup 99m}Tc(CO){sub 3}-GCV could contribute to the development of a new HSV1-tk gene imaging agent. (orig.)

  8. Th1 Th2, Tc1 Tc2 cells of patients with otolaryngological diseases

    Directory of Open Access Journals (Sweden)

    Nobuo Ohta

    2004-01-01

    Full Text Available Cytokines are important regulatory mediators secreted by T cells and other immunoactive cells. Based on the cytokine synthesis patterns, CD4 T cells can often be classified into at least two populations with different immune regulatory functions. The Th1 cells, producing interleukin (IL-2 and interferon (IFN-γ, are often associated with cell-mediated immune responses such as delayed type hypersensitivity (DTH, whereas Th2 cells, secreting IL-4, IL-5 and IL-13, usually provide B cell help and enhance allergic reactions. Naïve CD8 T cells, similar to CD4 T cells, can differentiate into at least two subsets of cytolytic effector cells with distinct cytokine patterns. The Tc1 cells secrete a Th 1 - like cytokine pattern, including IL-2 and IFN-γ. The Tc2 cells produce Th2 cytokines, including IL-4, IL-5 and 11—10. There is increasing evidence that Th1/Th2 and Tc1/Tc2 cytokine imbalance has been of patho- genetic importance in various diseases, such as allergic and autoimmune diseases. The present review article focuses on the evidence that the imbalance of Th1/Th2 and Tc1/Tc2 cytokines plays an important role in various otolaryngological diseases, such as Kimura's disease, Wegener's granulomatosism, acute perceptive hearing loss and Meniere's disease. It is concluded that the predominance of Th 1 or Th2 and Tc1 or Tc2 cells may contribute to the mechanism in the pathogenesis of these otolaryngological diseases.

  9. Bioreduction of Fe-bearing clay minerals and their reactivity toward pertechnetate (Tc-99)

    Science.gov (United States)

    Bishop, Michael E.; Dong, Hailiang; Kukkadapu, Ravi K.; Liu, Chongxuan; Edelmann, Richard E.

    2011-09-01

    99Technetium ( 99Tc) is a fission product of uranium-235 and plutonium-239 and poses a high environmental hazard due to its long half-life ( t1/2 = 2.13 × 10 5 y), abundance in nuclear wastes, and environmental mobility under oxidizing conditions [i.e., Tc(VII)]. Under reducing conditions, Tc(VII) can be reduced to insoluble Tc(IV). Ferrous iron, either in aqueous form (Fe 2+) or in mineral form [Fe(II)], has been used to reduce Tc(VII) to Tc(IV). However, the reactivity of Fe(II) from clay minerals, other than nontronite, toward immobilization of Tc(VII) and its role in retention of reduced Tc(IV) has not been investigated. In this study the reactivity of a suite of clay minerals toward Tc(VII) reduction and immobilization was evaluated. The clay minerals chosen for this study included five members in the smectite-illite (S-I) series, (montmorillonite, nontronite, rectorite, mixed layered I-S, and illite), chlorite, and palygorskite. Surface Fe-oxides were removed from these minerals with a modified dithionite-citrate-bicarbonate (DCB) procedure. The total structural Fe content of these clay minerals, after surface Fe-oxide removal, ranged from 0.7% to 30.4% by weight, and the structural Fe(III)/Fe(total) ratio ranged from 45% to 98%. X-ray diffraction (XRD) and Mössbauer spectroscopy results showed that after Fe oxide removal the clay minerals were free of Fe-oxides. Scanning electron microscopy (SEM) revealed that little dissolution occurred during the DCB treatment. Bioreduction experiments were performed in bicarbonate buffer (pH-7) with structural Fe(III) in the clay minerals as the sole electron acceptor, lactate as the sole electron donor, and Shewanella putrefaciens CN32 cells as a mediator. In select tubes, anthraquinone-2,6-disulfate (AQDS) was added as electron shuttle to facilitate electron transfer. In the S-I series, smectite (montmorillonite) was the most reducible (18% and 41% without and with AQDS, respectively) and illite the least (1% for both

  10. Bioreduction of Fe-bearing clay minerals and their reactivity toward pertechnetate (Tc-99)

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, Michael E.; Dong, Hailiang; Kukkadapu, Ravi K.; Liu, Chongxuan; Edelmann, Richard E.

    2011-07-01

    99Technetium (99Tc) is a fission product of uranium-235 and plutonium-239 and poses a high environmental hazard due to its long half-life (t1/2 = 2.13 x 105 y), abundance in nuclear wastes, and environmental mobility under oxidizing conditions [i.e., Tc(VII)]. Under reducing conditions, Tc(VII) can be reduced to insoluble Tc(IV). Ferrous iron [Fe(II)], either in aqueous form or in mineral form, has been used to reduce Tc(VII) to Tc(IV). However, the reactivity of Fe(II) from clay minerals, other than nontronite, toward immobilization of Tc(VII) and its role in retention of reduced Tc(IV) have not been investigated. In this study the reactivity of a suite of clay minerals toward Tc(VII) reduction and immobilization was evaluated. The clay minerals chosen for this study included five members in the smectite-illite (S-I) series, (montmorillonite, nontronite, rectorite, mixed layered I-S, and illite), chlorite, and palygorskite. Fe-oxides were removed from these minerals with a modified dithionite-citrate-bicarbonate (DCB) procedure. The total Fe content of these clay minerals, after Fe-oxide removal, ranged from 0.7 to 30.4% by weight, and the Fe(III)/Fe(total) ratio ranged from 44.9 to 98.5%. X-ray diffraction (XRD) and Mössbauer spectroscopy results showed that after Fe oxide removal the clay minerals were free of Fe-oxides. Scanning electron microscopy (SEM) revealed that little dissolution occurred during the DCB treatment. Bioreduction experiments were performed in bicarbonate buffer (pH-7) with Fe(III) in the clay minerals as the sole electron acceptor, lactate as the sole electron donor, and Shewanella Putrifaciens CN32 cells as mediators. In select tubes, anthraquinone-2,6-disulfate (AQDS) was added as electron shuttle to facilitate electron transfer. The extent of Fe(III) bioreduction was the highest for chlorite (~43 wt%) and the lowest for palygorskite (~4.17 wt%). In the S-I series, NAu-2 was the most reducible (~31 %) and illite the least (~0.4 %). The

  11. Preparation, quality control and biological evaluation of {sup 99m}Tc-labelled cationic steroid antibiotic (CSA-13)

    Energy Technology Data Exchange (ETDEWEB)

    Roohi, S.; Amir, N.; Mushtaq, A.; Salahuddin, S.M.; Jehangir, M. [Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan). Isotope Production Div.; Savage, P.B. [Brigham Young Univ., Provo, UT (United States). Dept. of Chemistry and Biochemistry

    2009-07-01

    Ceragenins (CSAs) are a new class of antimicrobial agents that display broad spectrum antibacterial activity and may find use in the treatment of various infections. A member of this class CSA-13 was labelled with {sup 99m}Tc using SnCl{sub 2}.H{sub 2}O as a reducing agent. The labelling efficiency depended on the ligand/reductant ratio, pH and volume of the reaction mixture. The radiochemical purity and stability of {sup 99m}Tc-CSA was determined by thin layer chromatography. Biodistribution studies of {sup 99m}Tc-CSA were performed in Sprague Dawley rats. Liver and spleen uptake was quite high. A significantly higher accumulation of {sup 99m}Tc-CSA was seen at sites of S. aureus infected rats. The results were compared with {sup 99m}Tc-Ciprofloxacin. (orig.)

  12. Sclerosing cholangitis: cholescintigraphy with Tc-99m-labeled DISIDA

    Energy Technology Data Exchange (ETDEWEB)

    Ament, A.E.; Bick, R.J.; Miraldi, F.D.; Haaga, J.R.; Wiedenmann, S.D.

    1984-04-01

    Four patients with primary sclerosing cholangitis (PCS) were examined with the hepatobiliary agent Tc-99m-labeled DISIDA (diisopropylphenylcarbamoyl iminodiacetic acid), and the results correlated with those of invasive cholangiography. Cholescintigraphy is superior to cholangiography in cases of suspected PSC where there is nonfilling of biliary radicals due to high-grade stenosis. The finding of delayed hepatic parenchymal clearance can allow estimation of the degree of obstruction of the various branches of the major bile ducts. Cholescintigraphy offers a noninvasive method of investigating patients with suspected sclerosing chloangitis, leading to earlier diagnosis. Confirmation with invasive cholangiographic procedures is recommended.

  13. Power Systems Development Facility Gasification Test Campaign TC22

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2008-11-01

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC22, the first test campaign using a high moisture lignite from Mississippi as the feedstock in the modified Transport Gasifier configuration. TC22 was conducted from March 24 to April 17, 2007. The gasification process was operated for 543 hours, increasing the total gasification operation at the PSDF to over 10,000 hours. The PSDF gasification process was operated in air-blown mode with a total of about 1,080 tons of coal. Coal feeder operation was challenging due to the high as-received moisture content of the lignite, but adjustments to the feeder operating parameters reduced the frequency of coal feeder trips. Gasifier operation was stable, and carbon conversions as high as 98.9 percent were demonstrated. Operation of the PCD and other support equipment such as the recycle gas compressor and ash removal systems operated reliably.

  14. Assessing Greater Sage-Grouse Selection of Brood-Rearing Habitat Using Remotely-Sensed Imagery: Can Readily Available High-Resolution Imagery Be Used to Identify Brood-Rearing Habitat Across a Broad Landscape?

    Directory of Open Access Journals (Sweden)

    Matthew Westover

    Full Text Available Greater sage-grouse populations have decreased steadily since European settlement in western North America. Reduced availability of brood-rearing habitat has been identified as a limiting factor for many populations. We used radio-telemetry to acquire locations of sage-grouse broods from 1998 to 2012 in Strawberry Valley, Utah. Using these locations and remotely-sensed NAIP (National Agricultural Imagery Program imagery, we 1 determined which characteristics of brood-rearing habitat could be used in widely available, high resolution imagery 2 assessed the spatial extent at which sage-grouse selected brood-rearing habitat, and 3 created a predictive habitat model to identify areas of preferred brood-rearing habitat. We used AIC model selection to evaluate support for a list of variables derived from remotely-sensed imagery. We examined the relationship of these explanatory variables at three spatial extents (45, 200, and 795 meter radii. Our top model included 10 variables (percent shrub, percent grass, percent tree, percent paved road, percent riparian, meters of sage/tree edge, meters of riparian/tree edge, distance to tree, distance to transmission lines, and distance to permanent structures. Variables from each spatial extent were represented in our top model with the majority being associated with the larger (795 meter spatial extent. When applied to our study area, our top model predicted 75% of naïve brood locations suggesting reasonable success using this method and widely available NAIP imagery. We encourage application of our methodology to other sage-grouse populations and species of conservation concern.

  15. Assessing Greater Sage-Grouse Selection of Brood-Rearing Habitat Using Remotely-Sensed Imagery: Can Readily Available High-Resolution Imagery Be Used to Identify Brood-Rearing Habitat Across a Broad Landscape?

    Science.gov (United States)

    Westover, Matthew; Baxter, Jared; Baxter, Rick; Day, Casey; Jensen, Ryan; Petersen, Steve; Larsen, Randy

    2016-01-01

    Greater sage-grouse populations have decreased steadily since European settlement in western North America. Reduced availability of brood-rearing habitat has been identified as a limiting factor for many populations. We used radio-telemetry to acquire locations of sage-grouse broods from 1998 to 2012 in Strawberry Valley, Utah. Using these locations and remotely-sensed NAIP (National Agricultural Imagery Program) imagery, we 1) determined which characteristics of brood-rearing habitat could be used in widely available, high resolution imagery 2) assessed the spatial extent at which sage-grouse selected brood-rearing habitat, and 3) created a predictive habitat model to identify areas of preferred brood-rearing habitat. We used AIC model selection to evaluate support for a list of variables derived from remotely-sensed imagery. We examined the relationship of these explanatory variables at three spatial extents (45, 200, and 795 meter radii). Our top model included 10 variables (percent shrub, percent grass, percent tree, percent paved road, percent riparian, meters of sage/tree edge, meters of riparian/tree edge, distance to tree, distance to transmission lines, and distance to permanent structures). Variables from each spatial extent were represented in our top model with the majority being associated with the larger (795 meter) spatial extent. When applied to our study area, our top model predicted 75% of naïve brood locations suggesting reasonable success using this method and widely available NAIP imagery. We encourage application of our methodology to other sage-grouse populations and species of conservation concern.

  16. Mismatched uptake of Tc-99m-ECD and Tc-99m-HMPAO in subacute cerebral infarction: Tc-99m-ECD for viability and Tc-99m-HMPAO for flow restoration

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D. S.; Hyun, I. Y.; Kim, S. K. [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)] [and others

    1997-07-01

    Tc-99m-HMPAO reflects tissue perfusion but Tc-99m-ECD uptake is affected by tissue viability in addition to tissue perfusion which the varied state of cellular retention of Tc-99m-ECD reflects. Luxuriously perfused area on Tc-99m-HMPAO SPECT implies that this cortex was already reperfused either spontaneously or after thrombolysis and that accompanied paralysis of vascular reactivity in those zones warms progressive deterioration. We tried to find out if we can use sequential Tc-99m-ECD/Tc-99m-HMPAO SPECT to reveal cortical perfusion and severity and range of risky areas of cerbral cortex despite reperfusion in sub-acute infarction. In 13 patients (M ; F =7 : 6, mean age 57 (range: 26-84)) with cortical (n=12) and basal ganglia infarction (1), we performed sequential Tc-99m-ECD/Tc-99m-HMPAO SPECT at the same position. At first, 555 MBq of Tc-99m-ECD was injected and imaged and then 1110 MBq of Tc-99m-HMPAO was injected again and imaged with the patients in situ, and the first image (Tc-99m-ECD) and the subtracted image (2nd- 1st : Tc-99m-HMPAO) were compared slice by slice. Study was done from 3 days to 31 days (16{+-}9) after ictus. Tc-99m-ECD uptake was always less than or equal to Tc-99m-HMPAO uptake at the lesion in all cases. Luxury perfusion was prominent in four patients. Mismatched uptake was found in 10 patients. Severity of mismatch showed diverse spectrum and was ranged from total middle cerebral artery territory (1 case) to peripheral thin zones around infarction (2 cases). The other 7 showed intermediate amount of tissues with mismatch , i.e., Tc-99m-ECD defects where Tc-99m-HMPAO uptake is in part increased, normal or decreased. Upon discharge, patients having more uptake with Tc-99m-ECD predicted improvement. Patients having mismatched uptake went dichotomous way. In conclusion, Tc-99m-ECD/Tc-99m-HMPAO sequential SPECT is feasible and reveal both tissue perfusion (Tc-99m-HMPAO ) and discrepant Tc-99m-ECD uptake probably reflecting viability in acute

  17. PREFACE: 2013 Joint IMEKO (International Measurement Confederation) TC1-TC7-TC13 Symposium: Measurement Across Physical and Behavioural Sciences

    Science.gov (United States)

    Battista Rossi, Giovanni; Crenna, Francesco; Belotti, Vittorio

    2013-09-01

    The 2013 Joint IMEKO (International Measurement Confederation) TC1-C7-TC13 was organised by the University of Genova - DIME/MEC, Measurement Laboratory, Italy, on 4-6 September 2013. The work of this symposium is reported in this volume. The scope of the symposium includes the main topics covered by the above Technical Committees: TC1 Education and Training in Measurement and Instrumentation TC7 Measurement Science TC13 Measurements in Biology and Medicine This is in keeping with the tradition set by the previous events of this well established series. There has been a special focus on measurement across physical and behavioural sciences, with the aim of highlighting the interdisciplinary character of measurement science and of promoting constructive interactions with scientists in other disciplines. The discussion was introduced by keynote lectures on measurement challenges in psychophysics, psychometrics and quantum physics. The symposium was attended by experts working in these areas from 18 countries, including USA, Australia and Japan, and provided a useful forum for them to share and exchange their work and ideas. In total over sixty papers are included in the volume, organised according to the presentation sessions. Each paper was independently peer-reviewed by two reviewers from a distinguished international panel. The Symposium was held in Genova, which was the European Capital of Culture in 2004, and took place in Palazzo Ducale, an important historical building whose construction started in the 13th century, and that has been the house of the Duke of Genova from the 14th century. Genova, whose name comes from the Latin word 'Janua' (meaning 'door', as January is the door month of the year), has been regarded over the centuries as a door connecting Europe with the different countries and cultures of the Mediterranean basin and thus was an appropriate site for an international symposium involving different and new scientific visions and approaches to

  18. Evaluation of {sup 99m}Tc(CO){sub 5}I as a potential lung perfusion agent

    Energy Technology Data Exchange (ETDEWEB)

    Miroslavov, Alexander E.; Gorshkov, Nikolay I.; Lumpov, Alexander L. [Division of Radiochemical Research, Khlopin Radium Institute, 2nd Murinskii pr. 28, 194021, St Petersburg (Russian Federation); Yalfimov, Anatoly N. [Nuclear Medicine Department, Central Research Institute of Roentgenology and Radiology, Leningradskaya str. 70/4, 197000, St Petersburg (Russian Federation); Suglobov, Dmitrii N. [Division of Radiochemical Research, Khlopin Radium Institute, 2nd Murinskii pr. 28, 194021, St Petersburg (Russian Federation); Ellis, Beverley L. [Department of Nuclear Medicine, Manchester Royal Infirmary, M13 9WL Manchester (United Kingdom)], E-mail: bev.ellis@manchester.ac.uk; Braddock, Rattana; Smith, Anne-Marie [Imaging Science and Biomedical Engineering, School of Cancer and Imaging Science, Stopford Building, The University of Manchester, Oxford Road, Manchester M13 9PT (United Kingdom); Prescott, Mary C.; Lawson, Richard S. [Department of Nuclear Medicine, Manchester Royal Infirmary, M13 9WL Manchester (United Kingdom); Sharma, Harbans L. [Imaging Science and Biomedical Engineering, School of Cancer and Imaging Science, Stopford Building, The University of Manchester, Oxford Road, Manchester M13 9PT (United Kingdom)

    2009-01-15

    percentage of injected dose per organ {+-}S.D. at 1 h was as follows: lung, 22.47{+-}2.31; liver, 10.53{+-}1.8; heart, 0.18{+-}0.01; kidney, 1.2{+-}0.17. Tissue distribution studies with {sup 99m}Tc-MAA showed 100% lung uptake. Conclusion: {sup 99m}Tc(CO){sub 5}I was synthesized with a high radiochemical purity and showed a high accumulation in the lungs. Further work on the mechanism and optimization of lung uptake of {sup 99m}Tc-pentacarbonyl complexes is warranted.

  19. Synthesis and Characterization of Tc(I) Carbonyl Nitrosyl Species Relevant to the Hanford Tank Waste: FY 2016 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Gabriel B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chatterjee, Sayandev [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Levitskaia, Tatiana G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Martin, Thibaut J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wall, Nathalie [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Walter, Eric D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-11-24

    Among long-lived radioactive constituents in the Hanford tank waste, Tc presents a unique challenge in that it exists predominantly in the liquid phase, generally in the anionic form of pertechnetate, TcO4-, which is highly volatile at low-activity waste (LAW) vitrification melter temperatures and mobile in the Hanford site’s subsurface environment. The complex behavior of Tc under storage, treatment, and immobilization conditions significantly affects its management options, which to-date remain uncertain. In strongly alkaline environments, Tc exists as pertechnetate, TcO4- (oxidation state +7), and in the reduced forms (oxidation state < +7) collectively known as non-pertechnetate species. Pertechnetate is a well-characterized, anionic Tc species that can be removed from LAW by anion exchange or solvent extraction methods. There is no definitive information on the origin of the non-pertechnetate Tc species, nor is there a comprehensive description of their composition and behavior. It has been recently proposed that the non-pertechnetate species can comprise Tc(I) metal center and carbonyl or mixed carbonyl nitrosyl ligands stabilizing low-valent Tc. Recent work by our group has significantly expanded this previous work, generating a series of Tc(I) carbonyl compounds and demonstrating that they can be generated from reduction of TcO4- in the simulated Hanford tank waste in presence of CO at elevated temperature (Levitskaia et al. 2014). These results are consistent with the previous proposal that [Tc(CO)3]+ species can be present in the Hanford tank waste and suggest that the low Tc(I) oxidation state is stabilized by the π-accepting ability of the CO ligands. The continuation work has been initiated to develop model Tc carbonyl nitrosyl compounds and investigate their potential presence in the Hanford tank wastes. This report summarizes our to-date results.

  20. Superplastic Deformation of TC6 Alloy

    Directory of Open Access Journals (Sweden)

    DING Ling

    2016-12-01

    Full Text Available The superplastic tensile tests of TC6 alloy were conducted in the temperature range of 800-900℃ by using the maximum m value superplasticity deformation (Max m SPD method and the constant strain rate deformation method at the strain rate range of 0.0001-0.1 s-1. The stress-strain curve of the tensile tests was obtained and the microstructure near the fracture were analyzed by metallographic microscope. The result shows that the superplasticity of TC6 alloy is excellent, and the elongation increases first and then decreases with the increase of strain rate or temperature. When the temperature is 850℃ and strain rate is 0.001 s-1 at constant stain rate tensile tests, the elongation reaches up to 993%. However, the elongation using Max m SPD method at 850℃ is 1353%. It is shown that the material can achieve better superplasticity by using Max m SPD tensile compared to constant stain rate tensile under the same temperature. The superplastic deformation of TC6 alloy can enhance the dynamic recrystallization behavior significantly, the dynamic recrystallization behavior is promoted when strain rate and temperature are increased.