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Sample records for 217at 213po 209pb

  1. Half-lives of 221Fr, 217At, 213Bi, 213Po and 209Pb from the 225Ac decay series.

    PubMed

    Suliman, G; Pommé, S; Marouli, M; Van Ammel, R; Stroh, H; Jobbágy, V; Paepen, J; Dirican, A; Bruchertseifer, F; Apostolidis, C; Morgenstern, A

    2013-07-01

    The half-lives of (221)Fr, (217)At, (213)Bi, (213)Po, and (209)Pb were measured by means of an ion-implanted planar Si detector for alpha and beta particles emitted from weak (225)Ac sources or from recoil sources, which were placed in a quasi-2π counting geometry. Recoil sources were prepared by collecting atoms from an open (225)Ac source onto a glass substrate. The (221)Fr and (213)Bi half-lives were determined by following the alpha particle emission rate of recoil sources as a function of time. Similarly, the (209)Pb half-life was determined from the beta particle count rate. The shorter half-lives of (217)At and (213)Po were deduced from delayed coincidence measurements on weak (225)Ac sources using digital data acquisition in list mode. The resulting values: T1/2((221)Fr)=4.806 (6) min, T1/2((217)At)=32.8 (3)ms, T1/2((213)Bi)=45.62 (6)min, T1/2((213)Po)=3.708 (8) μs, and T1/2((209)Pb)=3.232 (5)h were in agreement only with the best literature data.

  2. High-spin states in the five-valence-particle nucleus {sup 213}Po

    SciTech Connect

    Astier, Alain; Porquet, Marie-Genevieve

    2011-03-15

    Excited states in {sup 213}Po have been populated using the {sup 18}O+ {sup 208}Pb reaction at 85 MeV beam energy and studied with the Euroball IV {gamma} multidetector array. The level scheme has been built up to {approx}2.0 MeV excitation energy and spin I{approx}25/2({h_bar}/2{pi}) from the triple {gamma} coincidence data. Spin and parity values of several yrast states have been assigned from the {gamma} angular properties. The configurations of the yrast states are discussed using results of empirical shell-model calculations and by analogy with the neighboring nuclei. The spin and parity values of several low-spin states of {sup 213}Po previously identified from the {beta} decay of {sup 213}Bi are revised.

  3. Diverse impacts of a step and repeated BDE209-Pb exposures on accumulation and metabolism of BDE209 in earthworms.

    PubMed

    Zhang, Wei; Liang, Jun; Li, Jing; Lin, Kuangfei; Fu, Rongbing

    2016-09-01

    Decabromodiphenyl ether (BDE209) and lead (Pb) are the two common contaminants at e-waste recycling sites (EWRSs). A laboratory incubation study was conducted to explore the impacts of a step and repeated BDE209-Pb exposures on accumulation and metabolism of BDE209 in earthworms Eisenia fetida for the first time. The results indicated that BDE209 concentrations in repetitively-polluted soils were clearly higher. And the existence of high-level Pb could promote the bioaccumulation of BDE209 in earthworms along the exposure time. The post-clitellum contents of BDE209 were more than the pre-clitellum during the entire incubation. Additionally, GC/MS analysis results demonstrated that BDE206, BDE208, BDE153, BDE99, BDE47 and BDE28 could be detected in Eisenia fetida throughout 28-d experiment, and BDE206 and BDE208 were predominant metabolic products. A step exposure decreased the capability to metabolize BDE209 in the presence of Pb. Average bioaccumulation factor (BAF) for a step treatment was 0.525, as well as it was more than 1.1 times that of repeated exposure (BAF = 0.48). SEM observations suggested that a step exposure mode aggravated the damage in earthworms than repeated exposure. The results and related findings will establish a useful scientific basis for soil ecological risk assessment at EWRSs.

  4. Level structure of the shell-model nucleus [sup 217]At

    SciTech Connect

    Sheline, R.K. ); Liang, C.F.; Paris, P. )

    1995-03-01

    Alpha recoil separation of a large number of [sup 221]Fr sources from a pure almost massless source of [sup 225]Ac made possible the study of the level structure of [sup 217]At following alpha decay from [sup 221]Fr. Alphas in coincidence with all gammas and gammas and electrons in coincidence with [sup 221]Fr alphas were used in this study. The levels in [sup 217]At can be interpreted in terms of the [pi]([ital h][sub 9/2])[sup 3] [nu]([ital g][sub 9/2])[sup [minus]4], [pi]([ital h][sub 9/2])[sup 2] f[sub 7/2] [nu]([ital g][sub 9/2])[sup [minus]4], and [pi]([ital h][sub 9/2])[sup 2] [ital i][sub 13/2] [nu]([ital g][sub 9/2])[sup [minus]4] shell-model configurations. Considerable similarity in the configurations and energies of the states of [sup 217]At and [sup 215]At is observed. The only change is in the neutron part of the configurations where the particle'' partial configuration in [sup 215]At (...[nu]([ital g][sub 9/2])[sup 4]) is replaced by the hole'' partial configuration in [sup 217]At (...[nu]([ital g][sub 9/2])[sup [minus]4]). No evidence for parity doublets is found in [sup 217]At.

  5. Possible cluster preformation in the 14C decay of 223Ra

    NASA Astrophysics Data System (ADS)

    Hussonnois, M.; Le Du, J. F.; Brillard, L.; Ardisson, G.

    1990-08-01

    A recent experiment on the 14C fine structure has shown that the branching ratio to 209Pb ground state is quite different from the one predicted by the various models of cluster emission. Assuming that the 14C is preformed in the 223Ra nucleus, we have calculated the hindrance factor F14C of the three 14C branches to 209Pb states with a barrier penetrability approximated by a square-well Coulomb potential. The F14C=3.9 and 4.6 values found for the 14C transitions to the two excited states at 779 keV (Iπ=11/2+) and 1423 keV (Iπ=15/2-), respectively, reveal that the cluster formation amplitudes in both transitions are close to those of the 222Ra and 224Ra 14C decays. Such values could be the result of ||nlj> shell-model components common to both the wave functions of the octupole deformed 223Ra nucleus and of the two first excited states of 209Pb spherical nucleus. The high hindrance factor F14C=583 of the 14C branch to the 209Pb ground state (Iπ=9/2+) could reveal the absence of ||1g9/2> shell-model component in the 223Ra wave function.

  6. Comment on ``Interpretation of the fine structure in the 14C radioactive decay of 223'

    NASA Astrophysics Data System (ADS)

    Hussonnois, M.; Le Du, J. F.; Brillard, L.; Ardisson, G.

    1991-12-01

    Priority of our interpretation of the fine structure in the 14C radioactive decay of 223Ra is asserted. It seems that the deformation parameter values, used in the framework of ARM to interpret properties of both 223Ra ground and excited states, partly allow for the qualitative interpretation of the experimental hindrance factors to the 209Pb states.

  7. Nuclear levels and structure from the decays of 213Bi and 209Tl

    NASA Astrophysics Data System (ADS)

    Ardisson, G.; Barci, V.; El Samad, O.

    1998-02-01

    Direct γ and γ-γ coincidence spectra of pure 209Tl and 213Bi sources obtained by radiochemical continuous separation were measured with coaxial and planar HPGe detectors. In 209Tl the half-life was measured, the β-decay energies and intensities of 11 γ transitions were reported, and a new decay scheme was proposed. In 213Bi β decay 22 transitions were observed, of which 18 were assigned to a new 213Po level scheme accounting for 9 excited states.

  8. Double-magic nature of 132Sn and 208Pb through lifetime and cross-section measurements.

    PubMed

    Allmond, J M; Stuchbery, A E; Beene, J R; Galindo-Uribarri, A; Liang, J F; Padilla-Rodal, E; Radford, D C; Varner, R L; Ayres, A; Batchelder, J C; Bey, A; Bingham, C R; Howard, M E; Jones, K L; Manning, B; Mueller, P E; Nesaraja, C D; Pain, S D; Peters, W A; Ratkiewicz, A; Schmitt, K T; Shapira, D; Smith, M S; Stone, N J; Stracener, D W; Yu, C-H

    2014-05-02

    Single-neutron states in (133)Sn and (209)Pb, which are analogous to single-electron states outside of closed atomic shells in alkali metals, were populated by the ((9)Be, (8)Be) one-neutron transfer reaction in inverse kinematics using particle-γ coincidence spectroscopy. In addition, the s(1/2) single-neutron hole-state candidate in (131)Sn was populated by ((9)Be, (10)Be). Doubly closed-shell (132)Sn (radioactive) and (208)Pb (stable) beams were used at sub-Coulomb barrier energies of 3 MeV per nucleon. Level energies, γ-ray transitions, absolute cross sections, spectroscopic factors, asymptotic normalization coefficients, and excited-state lifetimes are reported and compared with shell-model expectations. The results include a new transition and precise level energy for the 3p(1/2) candidate in (133)Sn, new absolute cross sections for the 1h(9/2) candidate in (133)Sn and 3s(1/2) candidate in (131)Sn, and new lifetimes for excited states in (133)Sn and (209)Pb. This is the first report on excited-state lifetimes of (133)Sn, which allow for a unique test of the nuclear shell model and (132)Sn double-shell closure.

  9. Double-magic nature of 132Sn and 208Pb through lifetime and cross-section measurements

    SciTech Connect

    Allmond, James M; Stuchbery, Andrew E; Beene, James R; Galindo-Uribarri, Alfredo {nmn}; Liang, J Felix; Padilla-Rodal, Elizabeth; Radford, David C; Varner Jr, Robert L; Ayres, A.; Batchelder, J. C.; Bey, A.; Bingham, C. R.; Howard, Meredith E; Jones, K. L.; Manning, Brett M; Mueller, Paul Edward; Nesaraja, Caroline D; Pain, Steven D; Peters, William A; Ratkiewicz, Andrew J; Schmitt, Kyle; Shapira, Dan; Smith, Michael Scott; Stone, N. J.; Stracener, Daniel W; Yu, Chang-Hong

    2014-01-01

    Single-neutron states in 133Sn and 209Pb, which are analogous to single electrons outside of closed atomic shells in alkali metals, were populated by the (9Be,8Be) one-neutron transfer reaction in inverse kinematics using particle-gamma coincidence spectroscopy. In addition, the s1/2 single-neutron hole-state candidate in 131Sn was populated by (9Be,10Be). Doubly closed-shell 132Sn (radioactive) and 208Pb (stable) beams were used at sub-Coulomb barrier energies of 3 MeV per nucleon. Level energies, gamma-ray transitions, absolute cross sections, spectroscopic factors, asymptotic normalization coefficients, and excited-state lifetimes are reported and compared to shell-model expectations. The results include a new transition and precise level energy for the 3p1/2 candidate in 133Sn, new absolute cross sections for the 1h9/2 candidate in 133Sn and 3s1/2 candidate in 131Sn, and new lifetimes for excited states in 133Sn and 209Pb. This is the first report on excited-state lifetimes of 133Sn, which provide a unique signature of the single-neutron states and 132Sn double-shell closure.

  10. Identification of the 109Xe and 105Te Alpha-Decay Chain

    SciTech Connect

    Liddick, S. N.; Grzywacz, R.; Mazzocchi, C.; Page, R. D.; Rykaczewski, Krzysztof Piotr; Batchelder, J. C.; Bingham, C. R.; Darby, I. G.; Drafta, G.; Goodin, C.; Gross, Carl J; Hamilton, J. H.; Hecht, A. A.; Hwang, J. K.; Ilyushkin, S.; Joss, D. T.; Korgul, A.; Krolas, W.; Lagergren, K.; Li, K.; Tantawy, M. N.; Thomson, J.; Winger, J. A.

    2007-01-01

    The alpha-decay chain 109Xe-->105Te-->101Sn was identified at the Holifield Radioactive Ion Beam Facility. Advances in digital electronics have made possible the identification of both alpha emitters in the same experiment despite the disparate half-lives of 13+/_2ms and 620+/_70ns for 109Xe and 105Te, respectively. Two alpha-decay transitions were observed from 109Xe with Q/alpha values of 4067 +/_ 10 and 4217 +/_ 8keV. One transition between the ground states of 105Te and 101Sn was observed with a Q/alpha value of 4889 +/_6keV. Using the measured half-lives, branching ratios, and Q/alpha values the reduced alpha-decay widths, delta squared, were determined. Comparison of the delta squared value for 105Te with 213Po indicates a "superallowed" character in the alpha emission of 105Te.

  11. 209Tl half-life and gamma-ray measurements of radionuclides belonging to the (4 n + 1) decay chain

    NASA Astrophysics Data System (ADS)

    Ardisson, G.; Barci, V.; El Samad, O.

    1994-01-01

    Gamma-ray spectra of radiochemically separated 221Fr, 213Bi and 209Tl sources were measured using coaxial and planar HPGe detectors. The energies and emission probabilities of eight new gamma-ray transitions were observed in the decay of 209Tl; a half-life of (2.161±0.007) min was measured. Twenty-two gamma-rays have been attributed to the β-decay of 213Bi, of which 17 are new with respect to previous studies. The 213Po level scheme was determined using γ-γ coincidence measurements: eight excited states are proposed of which six are new. Preliminary measurements of the α-decay of 221Fr revealed the existence of 18 gamma-ray transitions of which eight are reported for the first time.

  12. Measurements of neutron capture cross section for {sup 207,208}Pb

    SciTech Connect

    Segawa, M.; Toh, Y.; Harada, H.; Kitatani, F.; Koizumi, M.; Fukahori, T.; Iwamoto, N.; Iwamoto, O.; Oshima, M.; Hatsukawa, Y.; Nagai, Y.; Igashira, M.; Kamada, S.; Tajika, M.

    2014-05-02

    The neutron capture cross sections for {sup 207,208}Pb have been measured in the neutron energy region from 10 to 110 keV. The γ-rays cascaded from a capture state to the ground state or low-lying states of {sup 208,209}Pb were observed for the first time, using an anti-Compton Nal(Tl) spectrometer and a TOF method. The observed discrete γ-ray energy spectra enabled us to determine neutron capture cross sections for {sup 207,208}Pb with small systematic errors, since we could distinguish γ-ray of {sup 207,208}Pb(n,γ) reactions from background γ-ray with use of the γ-ray spectra. The obtained cross sections include both contributions of resonance and direct capture components different from the previous TOF measurements.

  13. Coupled-Channel Models of Direct-Semidirect Capture via Giant-Dipole Resonances

    NASA Astrophysics Data System (ADS)

    Thompson, I. J.; Escher, J. E.; Arbanas, G.

    2014-04-01

    Semidirect capture, a two-step process that excites a giant-dipole resonance followed by its radiative de-excitation, is a dominant process near giant-dipole resonances, that is, for incoming neutron energies within 5-20 MeV. At lower energies such processes may affect neutron capture rates that are relevant to astrophysical nucleosynthesis models. We implement a semidirect capture model in the coupled-channel reaction code Fresco and validate it by comparing the cross section for direct-semidirect capture 208Pb(n,γ)209Pb to experimental data. We also investigate the effect of low-energy electric dipole strength in the pygmy resonance. We use a conventional single-particle direct-semidirect capture code Cupido for comparison. Furthermore, we present and discuss our results for direct-semidirect capture reaction 130Sn(n,γ)131Sn, the cross section of which is known to have a significant effect on nucleosynthesis models.

  14. Coupled-Channel Models of Direct-Semidirect Capture via Giant-Dipole Resonances

    SciTech Connect

    Thompson, I J; Escher, Jutta E; Arbanas, Goran

    2013-01-01

    Semidirect capture, a two-step process that excites a giant-dipole resonance followed by its radiative de-excitation, is a dominant process near giant-dipole resonances, that is, for incoming neutron energies within 5 20 MeV. At lower energies such processes may affect neutron capture rates that are relevant to astrophysical nucleosynthesis models. We implement a semidirect capture model in the coupled-channel reaction code Fresco and validate it by comparing the cross section for direct-semidirect capture 208Pb(n,g)209Pb to experimental data. We also investigate the effect of low-energy electric dipole strength in the pygmy resonance. We use a conventional single-particle direct-semidirect capture code Cupido for comparison. Furthermore, we present and discuss our results for direct-semidirect capture reaction 130Sn(n,g)131Sn, the cross section of which is known to have a significant effect on nucleosynthesis models.

  15. 14C cluster emission: a tool for the study of nuclear structures

    NASA Astrophysics Data System (ADS)

    Hussonnois, M.; Ardisson, G.

    1994-09-01

    A brief survey of the14C cluster emission of different radium isotopes will remind the first evidence for an odd-even effect in14C radioactivity. The discovery at the I.P.N. Orsay, of a fine structure in the14C emission of223Ra enhanced the development of this new investigation field. The qualitative interpretation of the favoured transitions to the first two excited states of the209Pb daughter nucleus offers a new possibility to better understand nuclear structures of heavy deformed nuclei. For instance, an accurate determination of the energy of the14C clusters emitted by225Ac and221Fr must allow to improve our knowledge of ground state configurations of these nuclei.

  16. Discovery of {sup 109}Xe and {sup 105}Te: Superallowed {alpha} Decay near Doubly Magic {sup 100}Sn

    SciTech Connect

    Liddick, S. N.; Batchelder, J. C.; Grzywacz, R.; Bingham, C. R.; Mazzocchi, C.; Drafta, G.; Tantawy, M. N.; Page, R. D.; Darby, I. G.; Joss, D. T.; Thomson, J.; Rykaczewski, K. P.; Gross, C. J.; Goodin, C.; Hamilton, J. H.; Hwang, J. K.; Li, K.; Hecht, A. A.; Ilyushkin, S.; Korgul, A.

    2006-08-25

    Two new {alpha} emitters {sup 109}Xe and {sup 105}Te were identified through the observation of the {sup 109}Xe{yields}{sup 105}Te{yields}{sup 101}Sn {alpha}-decay chain. The {sup 109}Xe nuclei were produced in the fusion-evaporation reaction {sup 54}Fe({sup 58}Ni,3n){sup 109}Xe and studied using the Recoil Mass Spectrometer at the Holifield Radioactive Ion Beam Facility. Two transitions at E{sub {alpha}}=4062{+-}7 keV and E{sub {alpha}}=3918{+-}9 keV were interpreted as the l=2 and l=0 transitions from the 7/2{sup +} ground state in {sup 109}Xe (T{sub 1/2}=13{+-}2 ms) to the 5/2{sup +} ground state and a 7/2{sup +} excited state, located at 150{+-}13 keV in {sup 105}Te. The observation of the subsequent decay of {sup 105}Te marks the discovery of the lightest known {alpha}-decaying nucleus. The measured transition energy E{sub {alpha}}=4703{+-}5 keV and half-life T{sub 1/2}=620{+-}70 ns were used to determine the reduced {alpha}-decay width {delta}{sup 2}. The ratio {delta}{sub {sup 105}Te}{sup 2}/{delta}{sub {sup 213}Po}{sup 2} of {approx}3 indicates a superallowed character of the {alpha} emission from {sup 105}Te.

  17. Testing the Perey effect

    DOE PAGES

    Titus, L. J.; Nunes, Filomena M.

    2014-03-12

    Here, the effects of non-local potentials have historically been approximately included by applying a correction factor to the solution of the corresponding equation for the local equivalent interaction. This is usually referred to as the Perey correction factor. In this work we investigate the validity of the Perey correction factor for single-channel bound and scattering states, as well as in transfer (p, d) cross sections. Method: We solve the scattering and bound state equations for non-local interactions of the Perey-Buck type, through an iterative method. Using the distorted wave Born approximation, we construct the T-matrix for (p,d) on 17O, 41Ca,more » 49Ca, 127Sn, 133Sn, and 209Pb at 20 and 50 MeV. As a result, we found that for bound states, the Perey corrected wave function resulting from the local equation agreed well with that from the non-local equation in the interior region, but discrepancies were found in the surface and peripheral regions. Overall, the Perey correction factor was adequate for scattering states, with the exception of a few partial waves corresponding to the grazing impact parameters. These differences proved to be important for transfer reactions. In conclusion, the Perey correction factor does offer an improvement over taking a direct local equivalent solution. However, if the desired accuracy is to be better than 10%, the exact solution of the non-local equation should be pursued.« less

  18. Lead isotopes and trace metal ratios of aerosols as tracers of Pb pollution sources in Kanpur, India

    NASA Astrophysics Data System (ADS)

    Sen, Indra; Bizimis, Michael; Tripathi, Sachchida; Paul, Debajyoti; Tyagi, Swati; Sengupta, Deep

    2015-04-01

    The anthropogenic flux of Pb in the Earth's surface is almost an order of magnitude higher than its corresponding natural flux [1]. Identifying the sources and pathways of anthropogenic Pb in environment is important because Pb toxicity is known to have adverse effects on human health. Pb pollution sources for America, Europe, and China are well documented. However, sources of atmospheric Pb are unknown in India, particularly after leaded gasoline was phased out in 2000. India has a developing economy with a rapidly emerging automobile and high temperature industry, and anthropogenic Pb emission is expected to rise in the next decade. In this study, we report on the Pb- isotope compositions and trace metal ratios of airborne particulates collected in Kanpur, an industrial city in northern India. The Pb concentration in the airborne particulate matter varies between 14-216 ng/m3, while the other heavy metals vary by factor of 10 or less, e.g. Cd=0.3-3 ng/m3, As=0.4-3.5 ng/m3, Zn=36-161 ng/m3, and Cu=3-22 ng/m3. The 206Pb/207Pb, 208Pb/206Pb, and 208Pb/207Pb vary between 1.112 - 1.129, 2.123-2.141, and 2.409-2.424 respectively, and are highly correlated with each other (R2>0.9). Pb isotopes and trace metal data reveals that coal combustion is the major source of anthropogenic Pb in the atmosphere, with limited contribution from mining and smelting processes. We further conclude that combination of Pb isotope ratios and V/Pb ratios are powerful tracers for Pb source apportionment studies, which is otherwise difficult to differentiate based only on Pb systematics [1] Sen and Peucker-Ehrenbrink (2012), Environ. Sci. Technol.(46), 8601-8609

  19. Breakthrough of 225Ac and its radionuclide daughters from an 225Ac/213Bi generator: development of new methods, quantitative characterization, and implications for clinical use.

    PubMed

    Ma, D; McDevitt, M R; Finn, R D; Scheinberg, D A

    2001-11-01

    Bisumth-213, a short-lived alpha particle emitting radionuclide, is generated from the decay of 225Ac, which has a half-life of 10 days. The development of a clinical 225Ac/213Bi generator and the preparation of a 213Bi radiolabeled antibody for radioimmunotherapy of leukemia have been reported. The 225Ac decay scheme is complex; therefore a thorough understanding of the impact of both the parent 225Ac and its daughters on radiolabeling, purification, and quantification is necessary for optimal use of the generator system. This paper reports: (i) unique new methods to measure 221Fr, 213Bi, and 209Pb, the prominent daughters of 225Ac; and (ii) a quantitative evaluation of 225Ac/213Bi generator breakthrough and the radionuclidic purity of 213Bi labeled radiopharmaceutical dose formulations. A quantitative multi-dimensional proportional scanning method was employed to distinguish and measure specific daughter radionuclides. This method combines thin layer chromatography in two perpendicular directions with attenuated collimation as a function of time for data collection and analysis. Francium-221 and 213Bi eluted differentially from the generator, and 221Fr contributed minimally to unchelated 213Bi in the reaction and final products. Lead-209 was present in the reaction solution, but not strongly bound by the chelating moiety either (i) under the 213Bi labeling reaction conditions or (ii) following chelated 213Bi decay. As a consequence of incorporating several new procedures to the operation of the generator, 225Ac breakthrough in the final product was further reduced and represented a trivial contaminant in the final drug formulations.

  20. High thermoelectric figure of merit in nanocrystalline polyaniline at low temperatures

    SciTech Connect

    Nath, Chandrani; Kumar, Ashok E-mail: okram@csr.res.in; Kuo, Yung-Kang; Okram, Gunadhor Singh E-mail: okram@csr.res.in

    2014-09-29

    Thermoelectric coolers with figure of merit (ZT) close to unity at low temperatures are the need of the hour with new advances in high temperature superconductors, superconducting microelectronic circuits, quantum computers, and photonics. Here, we demonstrate that the conducting polymer polyaniline (Pani) doped with camphor sulfonic acid synthesized in semi-crystalline nanostructures, possesses a giant Seebeck effect at low temperatures. The resulting enormously large Seebeck coefficient (up to 0.6 V/K) combined with an intrinsically low electrical conductivity and thermal conductivity give rise to a ZT = 0.77 at 45 K and ZT = 2.17 at 17 K.

  1. High thermoelectric figure of merit in nanocrystalline polyaniline at low temperatures

    NASA Astrophysics Data System (ADS)

    Nath, Chandrani; Kumar, Ashok; Kuo, Yung-Kang; Okram, Gunadhor Singh

    2014-09-01

    Thermoelectric coolers with figure of merit (ZT) close to unity at low temperatures are the need of the hour with new advances in high temperature superconductors, superconducting microelectronic circuits, quantum computers, and photonics. Here, we demonstrate that the conducting polymer polyaniline (Pani) doped with camphor sulfonic acid synthesized in semi-crystalline nanostructures, possesses a giant Seebeck effect at low temperatures. The resulting enormously large Seebeck coefficient (up to 0.6 V/K) combined with an intrinsically low electrical conductivity and thermal conductivity give rise to a ZT = 0.77 at 45 K and ZT = 2.17 at 17 K.

  2. Synthesis and Antiproliferative Activity of Steroidal Thiosemicarbazone Platinum (Pt(II)) Complexes

    PubMed Central

    Huang, Yanmin; Kong, Erbin; Gan, Chunfang; Liu, Zhiping; Lin, Qifu; Cui, Jianguo

    2015-01-01

    Steroidal compounds exhibit particular physiological activities. In this paper, some steroidal thiosemicarbazones platinum (Pt(II)) complexes were synthesized by the condensation of steroidal ketones with thiosemicarbazide using estrone, chenodeoxycholic acid, and 7-deoxycholic acid as starting materials and complexation of steroidal thiosesemicarbazones with Pt(II). The complexes were characterized by IR, NMR, and MS, and their antiproliferative activities were evaluated. The results showed that some steroidal thiosemicarbazones platinum (Pt(II)) complexes displayed moderate cytotoxicity to HeLa and Bel-7404 cells. Thereinto, complex 6 showed an excellent inhibited selectivity to HeLa cells with an IC50 value of 9.2 μM and SI value of 21.7. At the same time, all compounds were almost inactive to HEK293T (normal kidney epithelial cells). The information obtained from the studies may be useful for the design of novel chemotherapeutic drugs. PMID:26635511

  3. Tunnel magnetoresistance in epitaxially grown magnetic tunnel junctions using Heusler alloy electrode and MgO barrier

    SciTech Connect

    Tsunegi, S.; Sakuraba, Y.; Oogane, M.; Telling, N. D.; Shelford, L. R.; Arenholz, E.; van der Laan, G.; Hicken, R. J.; Takanashi, K.; Ando, Y.

    2009-07-01

    Epitaxially grown magnetic tunnel junctions (MTJs) with a stacking structure of Co{sub 2}MnSi/MgO/CoFe were fabricated. Their tunnel magnetoresistance (TMR) effects were investigated. The TMR ratio and tunnelling conductance characteristics of MTJs were considerably different between those with an MgO barrier prepared using sputtering (SP-MTJ) and those prepared using EB evaporation (EB-MTJ). The EB-MTJ exhibited a very large TMR ratio of 217% at room temperature and 753% at 2 K. The bias voltage dependence of the tunnelling conductance in the parallel magnetic configuration for the EB-MTJ suggests that the observed large TMR ratio at RT results from the coherent tunnelling process through the crystalline MgO barrier. The tunnelling conductance in the anti-parallel magnetic configuration suggests that the large temperature dependence of the TMR ratio results from the inelastic spin-flip tunnelling process.

  4. Effects of nonlocality on transfer reactions

    NASA Astrophysics Data System (ADS)

    Titus, Luke

    Nuclear reactions play a key role in the study of nuclei away from stability. Single-nucleon transfer reactions involving deuterons provide an exceptional tool to study the single-particle structure of nuclei. Theoretically, these reactions are attractive as they can be cast into a three-body problem composed of a neutron, proton, and the target nucleus. Optical potentials are a common ingredient in reactions studies. Traditionally, nucleon-nucleus optical potentials are made local for convenience. The effects of nonlocal potentials have historically been included approximately by applying a correction factor to the solution of the corresponding equation for the local equivalent interaction. This is usually referred to as the Perey correction factor. In this thesis, we have systematically investigated the effects of nonlocality on (p,d) and (d,p) transfer reactions, and the validity of the Perey correction factor. We implemented a method to solve the single channel nonlocal equation for both bound and scattering states. We also developed an improved formalism for nonlocal interactions that includes deuteron breakup in transfer reactions. This new formalism, the nonlocal adiabatic distorted wave approximation, was used to study the effects of including nonlocality consistently in ( d,p) transfer reactions. For the (p,d) transfer reactions, we solved the nonlocal scattering and bound state equations using the Perey-Buck type interaction, and compared to local equivalent calculations. Using the distorted wave Born approximation we construct the T-matrix for (p,d) transfer on 17O, 41Ca, 49Ca, 127 Sn, 133Sn, and 209Pb at 20 and 50 MeV. Additionally we studied (p,d) reactions on 40Ca using the the nonlocal dispersive optical model. We have also included nonlocality consistently into the adiabatic distorted wave approximation and have investigated the effects of nonlocality on on (d,p) transfer reactions for deuterons impinged on 16O, 40Ca, 48Ca, 126Sn, 132Sn, 208Pb at 10

  5. Digital Breast Tomosynthesis versus Supplemental Diagnostic Mammographic Views for Evaluation of Noncalcified Breast Lesions

    PubMed Central

    Bandos, Andriy I.; Ganott, Marie A.; Sumkin, Jules H.; Kelly, Amy E.; Catullo, Victor J.; Rathfon, Grace Y.; Lu, Amy H.; Gur, David

    2013-01-01

    Purpose: To compare the diagnostic performance of breast tomosynthesis versus supplemental mammography views in classification of masses, distortions, and asymmetries. Materials and Methods: Eight radiologists who specialized in breast imaging retrospectively reviewed 217 consecutively accrued lesions by using protocols that were HIPAA compliant and institutional review board approved in 182 patients aged 31–60 years (mean, 50 years) who underwent diagnostic mammography and tomosynthesis. The lesions in the cohort included 33% (72 of 217) cancers and 67% (145 of 217) benign lesions. Eighty-four percent (182 of 217) of the lesions were masses, 11% (25 of 217) were asymmetries, and 5% (10 of 217) were distortions that were initially detected at clinical examination in 8% (17 of 217), at mammography in 80% (173 of 217), at ultrasonography (US) in 11% (25 of 217), or at magnetic resonance imaging in 1% (2 of 217). Histopathologic examination established truth in 191 lesions, US revealed a cyst in 12 lesions, and 14 lesions had a normal follow-up. Each lesion was interpreted once with tomosynthesis and once with supplemental mammographic views; both modes included the mediolateral oblique and craniocaudal views in a fully crossed and balanced design by using a five-category Breast Imaging Reporting and Data System (BI-RADS) assessment and a probability-of-malignancy score. Differences between modes were analyzed with a generalized linear mixed model for BI-RADS–based sensitivity and specificity and with modified Obuchowski-Rockette approach for probability-of-malignancy–based area under the receiver operating characteristic (ROC) curve. Results: Average probability-of-malignancy–based area under the ROC curve was 0.87 for tomosynthesis versus 0.83 for supplemental views (P < .001). With tomosynthesis, the false-positive rate decreased from 85% (989 of 1160) to 74% (864 of 1160) (P < .01) for cases that were rated BI-RADS category 3 or higher and from 57% (663 of

  6. Cross-sectional study of malocclusion in Spanish children

    PubMed Central

    Montiel-Company, José M.; Bellot-Arcís, Carlos; Puertes-Fernández, Neus

    2014-01-01

    Objectives: This study was conducted to determine the orthodontic treatment need of the child population of the Valencia region of Spain, employing the DAI and the IOTN, to examine the relations between treatment need, socio-economic data and gender and to assess the diagnostic agreement between the two indices. Study Design: A cross-sectional descriptive study was conducted in a random representative sample of the schoolchild population of the Valencia region of Spain. The sample size was a total of 765 children aged 12 and 15 years at 39 schools. Results: The orthodontic treatment need assessed by the DAI was 21.7% at 12 years of age and 14.1% at 15 years. The orthodontic treatment need assessed by the IOTN DHC was 20.9% at 12 years of age and 12.7% at 15 years. The diagnostic agreement between the DAI and the modified IOTN was moderate, with Kappa scores of 0.426 at 12 years of age and 0.415 for the 15-year-old group. Conclusions: Approximately 20% of the children needed orthodontic treatment. Neither gender nor social class appeared to exert a significant influence on orthodontic treatment need. Key words:Orthodontics, epidemiology, children, malocclusion. PMID:23986013

  7. Optimal thermionic energy conversion with established electrodes for high-temperature topping and process heating. [coal combustion product environments

    NASA Technical Reports Server (NTRS)

    Morris, J. F.

    1980-01-01

    Applied research-and-technology (ART) work reveals that optimal thermionic energy conversion (TEC) with approximately 1000 K to approximately 1100 K collectors is possible using well established tungsten electrodes. Such TEC with 1800 K emitters could approach 26.6% efficiency at 27.4 W/sq cm with approximately 1000 K collectors and 21.7% at 22.6 W/sq cm with approximately 1100 K collectors. These performances require 1.5 and 1.7 eV collector work functions (not the 1 eV ultimate) with nearly negligible interelectrode losses. Such collectors correspond to tungsten electrode systems in approximately 0.9 to approximately 6 torr cesium pressures with 1600 K to 1900 K emitters. Because higher heat-rejection temperatures for TEC allow greater collector work functions, interelectrode loss reduction becomes an increasingly important target for applications aimed at elevated temperatures. Studies of intragap modifications and new electrodes that will allow better electron emission and collection with lower cesium pressures are among the TEC-ART approaches to reduced interelectrode losses. These solutions will provide very effective TEC to serve directly in coal-combustion products for high-temperature topping and process heating. In turn this will help to use coal and to use it well.

  8. Nitrogen-Doped Hollow Carbon Nanospheres for High-Performance Li-Ion Batteries.

    PubMed

    Yang, Yufen; Jin, Song; Zhang, Zhen; Du, Zhenzhen; Liu, Huarong; Yang, Jia; Xu, Hangxun; Ji, Hengxing

    2017-04-13

    N-doped carbon materials is of particular attraction for anodes of lithium-ion batteries (LIBs) because of their high surface areas, superior electrical conductivity, and excellent mechanical strength, which can store energy by adsorption/desorption of Li(+) at the interfaces between the electrolyte and electrode. By directly carbonization of zeolitic imidazolate framework-8 nanospheres synthesized by an emulsion-based interfacial reaction, we obtained N-doped hollow carbon nanospheres with tunable shell thickness (20 nm to solid sphere) and different N dopant concentrations (3.9 to 21.7 at %). The optimized anode material possessed a shell thickness of 20 nm and contained 16.6 at % N dopants that were predominately pyridinic and pyrrolic. The anode delivered a specific capacity of 2053 mA h g(-1) at 100 mA g(-1) and 879 mA h g(-1) at 5 A g(-1) for 1000 cycles, implying a superior cycling stability. The improved electrochemical performance can be ascribed to (1) the Li(+) adsorption dominated energy storage mechanism prevents the volume change of the electrode materials, (2) the hollow nanostructure assembled by the nanometer-sized primary particles prevents the agglomeration of the nanoparticles and favors for Li(+) diffusion, (3) the optimized N dopant concentration and configuration facilitate the adsorption of Li(+); and (4) the graphitic carbon nanostructure ensures a good electrical conductivity.

  9. Some properties of low-vapor-pressure braze alloys for thermionic converters

    NASA Technical Reports Server (NTRS)

    Bair, V. L.

    1978-01-01

    Density, dc electrical resistivity, thermal conductivity, and linear thermal expansion are measured for arc-melted rod-shaped samples of binary eutectics of Zr, Hf, Ru, Nb, Ir, Mo, Ta, Os, Re, and W selected as very-low-pressure braze fillers for thermionic converters. The first two properties are measured at 296 K for Zr-21.7 at% Ru, Zr-13 wt% W, Zr-19 wt% W, Zr-22.3 at% Nb, Nb-66.9 at% Ru, Hf-25.3 wt% Re, Zr-25.7 at% Ta, Hf-22.5 at% W, and Nb-35 wt% Mo. The last property is measured from 293 K to 2/3 melting point for specified alloys of different compositions. Resistivities of 0.000055 to 0.000181 ohm-cm are observed with the alloys having resistivities about ten times that of the less resistive constituent metal and about three times that of the more resistive constituent metal, except for Zr-19 wt% W and Nb-35 wt% Mo (greater resistivities). Thermal expansion coefficients vary from 0.000006 to 0.0000105/K. All brazes exhibit linear thermal expansion near that of their constituent metals.

  10. Nuclear Data Evaluation for Mass Chain A=217:Odd-Proton Nuclei.

    PubMed

    Nafee, Sherif S; Shaheen, Salem A; Al-Ramady, Amir M

    2016-01-01

    Thallium (81(217)Tl, Bismuth (83(217)Bi), Astatine (85(217)At), Francium (87(217)Fr), Actinium (89(217)Ac) and Protactinium (91(217)Pa) are of odd-proton numbers among the mass chain A = 217. In the present work, the half-lives and gamma transitions for the six nuclei have been studied and adopted based on the recently published interactions or unevaluated nuclear data sets XUNDL. The Q (α) has been updated based on the recent published work of the Atomic Mass Evaluation AME2012 as well. Moreover, the total conversion electrons as well as the K-Shell to L-Shell, L-Shell to M-Shell and L-Shell to N-Shell Conversion Electron Ratios have been calculated using BrIcc code v2.3. An updated skeleton decay scheme for each of the above nuclei has been presented here. The decay hindrance factors (HF) calculated using the ALPHAD program, which is available from Brookhaven National Laboratory's website, have been calculated for the α- decay data sets for (221)Fr-, (221)Ac- and (221)Pa-α-decays.

  11. Prognostic features of patients with myelodysplastic syndromes aged < 50 years: update of a single-institution experience.

    PubMed

    Breccia, Massimo; Finsinger, Paola; Loglisci, Giuseppina; Santopietro, Michelina; Salaroli, Adriano; Serrao, Alessandra; Latagliata, Roberto; Volpicelli, Paola; Petrucci, Luigi; Nanni, Mauro; Alimena, Giuliana

    2012-12-01

    Fewer than 10% of patients with myelodysplastic syndromes (MDS) are younger than 50 years. A series of 91 younger patients (median age 44 years with female prevalence) are reported and compared with elderly patients. Frequent karyotypic changes were trisomy 8 (9.8%) and monosomy 7 (5%). Twenty-three patients had occupational exposure to potential mutagens (benzene and solvents), with a male predominance, higher frequency of refractory cytopenia with multilineage dysplasia (RCMD) (52%) and higher frequency of monosomy 7 (21.7%). At a median follow-up of 72 months, 22 patients (24%) evolved to acute leukemia, with higher frequency being observed among the exposed cohort (39% vs. 19% non-exposed). Unfavorable factors for overall survival were: age > 40 years, > 5% of blasts, trilinear bone marrow involvement and intermediate-high World Health Organization Prognostic Scoring System (WPSS) risk. The present results suggest that younger MDS could be identified as a distinct subset. For patients belonging to the low/intermediate-I risk group, due to a low transformation rate, aggressive approaches should rarely be recommended.

  12. Analyses of Antibacterial Activity and Cell Compatibility of Titanium Coated with a Zr–C–N Film

    PubMed Central

    Chang, Yin-Yu; Huang, Heng-Li; Lai, Chih-Ho; Hsu, Jui-Ting; Shieh, Tzong-Ming; Wu, Aaron Yu-Jen; Chen, Chao-Ling

    2013-01-01

    Objective The purpose of this study was to verify the antibacterial performance and cell proliferation activity of zirconium (Zr)–carbon (C)–nitride (N) coatings on commercially pure titanium (Ti) with different C contents. Materials and Methods Reactive nitrogen gas (N2) with and without acetylene (C2H2) was activated by Zr plasma in a cathodic-arc evaporation system to deposit either a zirconium nitride (ZrN) or a Zr–C–N coating onto Ti plates. The bacterial activity of the coatings was evaluated against Staphylococcus aureus with the aid of SYTO9 nucleic acid staining and scanning electron microscopy (SEM). Cell compatibility, mRNA expression, and morphology related to human gingival fibroblasts (HGFs) on the coated samples were also determined by using the MTT assay, reverse transcriptase–polymerase chain reaction, and SEM. Results The Zr–C–N coating with the highest C content (21.7 at%) exhibited the lowest bacterial preservation (P<0.001). Biological responses including proliferation, gene expression, and attachment of HGF cells to ZrN and Zr–C–N coatings were comparable to those of the uncoated Ti plate. Conclusions High-C-content Zr–C–N coatings not only provide short-term antibacterial activity against S. aureus but are also biocompatible with HGF cells. PMID:23431391

  13. Metallic cobalt and iron particles in large and medium pore zeolites. Methods of generation and ferromagnetic resonance characterization

    SciTech Connect

    Iton, L.E.; Beal, R.B.; Hamot, P.J.

    1983-01-01

    Spectroscopic studies utilizing photoacoustic electronic spectroscopy, electron paramagnetic resonance, and ferromagnetic resonance have been made on the formation of (1) Co metal particles from CO(NH/sub 3/)/sub 6//sup 3 +/ exchanged into Y zeolite and (2) Fe metal particles from nonframework Fe/sup 3 +/ ions in an aluminoferrisilicate analogue of ZSM-5 zeolite. Decomposition of the Co(NH/sub 3/)/sub 6//sup 3 +/ complex is accompanied by autoreduction to the Co/sup 2 +/ state, observed by EPR at 7/sup 0/K, but no Co metal is formed. The Co/sup 2 +/ ions migrate from the supercage locations of the parent complexes into the hexagonal prisms and are subsequently very difficult to reduce, even with H/sub 2/ at 823/sup 0/K. High-temperature FMR data suggest that the small amount of Co metal particles which are formed exist with the fcc crystal structure yielding g = 2.17 at 508/sup 0/K, consistent with an empirically calculated value for fcc Co. Hexagonal close packed Co particles are expected to exhibit much larger magnetic anisotropy than was observed. The Fe/sup 3 +/ ions in the medium pore pentasil aluminoferrisilicate zeolite can be reduced to the metallic state following either (a) precipitation of the inclusion compound, Fe/sup III/(Fe/sup II/(CN)/sub 5/(NO)), in the zeolite, or (b) generation of superparamagnetic oxidic ferric ion clusters. High-temperature FMR data establish that smaller Fe particles can be obtained by the latter method.

  14. Optimal thermionic energy conversion with established electrodes for high-temperature topping and process heating

    SciTech Connect

    Morris, J.F.

    1980-07-01

    Advantages of thermionic energy conversion (TEC) have been counted and are recounted with emphasis on high-temperature service in coal-combustion products. Efficient, economical, nonpolluting utilization of coal here and now is a critically important national goal. And TEC can augment this capability not only by the often proposed topping of steam power plants but also by higher-temperature topping and process heating. For these applications, applied-research-and-technology (ART) work reveals that optimal TEC with approx. 1000-to approx. 1100 K collectors is possible using well-established tungsten electrodes. Such TEC with 1800 K emitters could approach 26.6% efficiency at 27.4 W/cm/sup 2/ with approx. 1000 K collectors and 21.7% at 22.6 W/cm/sup 2/ with approx. 1100 K collectors. These performances require 1.5- and 1.7-eV collector work functions (not the 1-eV ultimate) with nearly negligible interelectrode losses. Such collectors correspond to tungsten electrode systems in approx. 0.9-to approx. 6-torr cesium pressures with 1600-to-1900 K emitters. Because higher heat-rejection temperatures for TEC allow greater collector work functions, interelectrode-loss reduction becomes an increasingly important target for applications aimed at elevated temperatures. Studies of intragap modifications and new electrodes that will allow better electron emission and collection with lower cesium pressures are among the TEC-ART approaches to reduced interelectrode losses. These solutions will provide very effective TEC to serve directly in coal-combustion products for high-temperature topping and process heating. In turn this will help to use coal-and to use it well.

  15. [Spectral analysis of polyphenol oxidase (PPO) and lipoxygenase (LOX) treated by pulsed electric field].

    PubMed

    Luo, Wei; Zhang, Ruo-Bing; Chen, Jie; Wang, Li-Ming; Guan, Zhi-Cheng; Jia, Zhi-Dong

    2009-08-01

    Inactivation effect of pulsed electric field (PEF) on polyphenol oxidase (PPO) and lipoxygenase (LOX) was investigated using a laboratory PEF system with a coaxial treatment chamber. Circular dichroism (CD) and fluorescence analysis were used to study the conformation change of the protein. The experimental results show that PPO and LOX can be effectively inactivated by the PEF treatment. Inactivation effect of PPO and LOX increases with the increase in the applied electric strength and the treatment time. Activity of PPO and LOX can be reduced by 60.3% and 21.7% at 20 kV x cm(-1) after being treated for 320 micros respectively. The decrease of the negative peaks (208 and 215 nm in PPO spectra, 208 nm and 218 nm in LOX spectra) in CD spectra of PPO and LOX shows that PEF treatment caused a loss of alpha-helix and increase in beta-sheet content, indicating that conformation changes occur in the secondary structure of PPO and LOX enzyme. This effect was strengthened as the applied electric field increased: alpha-helical content of PPO and LOX was 56% and 29% after being treated at 8 kV x cm(-1), however, when the electric field was increased up to 20 kV x cm(-1), alpha-helical content of PPO and LOX decreased to 21% and 16% respectively. The decrease rate of alpha-helix and increase rate of beta-sheet in PPO are higher than LOX, indicating that the second conformation of PPO is less resistant to PEF treatment than LOX. The fluorescence intensity of LOX increases after PEF treatment. At the same time, increasing the applied pulsed electric field increases the fluorescence intensity emitted. Fluorescence measurements confirm that tertiary conformation changes occur in the local structure of LOX. However the possible mechanism of the conformation change induced by the PEF treatment is beyond the scope of the present investigation.

  16. Crystal Structures of a Piscine Betanodavirus: Mechanisms of Capsid Assembly and Viral Infection

    PubMed Central

    Chen, Nai-Chi; Yoshimura, Masato; Guan, Hong-Hsiang; Wang, Ting-Yu; Misumi, Yuko; Lin, Chien-Chih; Chuankhayan, Phimonphan; Nakagawa, Atsushi; Chan, Sunney I.; Tsukihara, Tomitake; Chen, Tzong-Yueh; Chen, Chun-Jung

    2015-01-01

    Betanodaviruses cause massive mortality in marine fish species with viral nervous necrosis. The structure of a T = 3 Grouper nervous necrosis virus-like particle (GNNV-LP) is determined by the ab initio method with non-crystallographic symmetry averaging at 3.6 Å resolution. Each capsid protein (CP) shows three major domains: (i) the N-terminal arm, an inter-subunit extension at the inner surface; (ii) the shell domain (S-domain), a jelly-roll structure; and (iii) the protrusion domain (P-domain) formed by three-fold trimeric protrusions. In addition, we have determined structures of the T = 1 subviral particles (SVPs) of (i) the delta-P-domain mutant (residues 35−217) at 3.1 Å resolution; and (ii) the N-ARM deletion mutant (residues 35−338) at 7 Å resolution; and (iii) the structure of the individual P-domain (residues 214−338) at 1.2 Å resolution. The P-domain reveals a novel DxD motif asymmetrically coordinating two Ca2+ ions, and seems to play a prominent role in the calcium-mediated trimerization of the GNNV CPs during the initial capsid assembly process. The flexible N-ARM (N-terminal arginine-rich motif) appears to serve as a molecular switch for T = 1 or T = 3 assembly. Finally, we find that polyethylene glycol, which is incorporated into the P-domain during the crystallization process, enhances GNNV infection. The present structural studies together with the biological assays enhance our understanding of the role of the P-domain of GNNV in the capsid assembly and viral infection by this betanodavirus. PMID:26491970

  17. THE SIMPLE SURVEY: OBSERVATIONS, REDUCTION, AND CATALOG

    SciTech Connect

    Damen, M.; Franx, M.; Taylor, E. N.; Labbe, I.; Van Dokkum, P. G.; Muzzin, A.; Brandt, W. N.; Dickinson, M.; Gawiser, E.; Illingworth, G. D.; Marchesini, D.; Papovich, C.; Rix, H.-W.

    2011-01-20

    We present the Spitzer IRAC/MUSYC Public Legacy Survey in the Extended CDF-South (SIMPLE), which consists of deep IRAC observations covering the {approx}1600 arcmin{sup 2} area surrounding GOODS-S. The limiting magnitudes of the SIMPLE IRAC mosaics typically are 23.8, 23.6, 21.9, and 21.7, at 3.6 {mu}m, 4.5 {mu}m, 5.8 {mu}m, and 8.0 {mu}m, respectively (5{sigma} total point source magnitudes in AB). The SIMPLE IRAC images are combined with the 10' x 15' GOODS IRAC mosaics in the center. We give detailed descriptions of the observations, data reduction, and properties of the final images, as well as the detection and photometry methods used to build a catalog. Using published optical and near-infrared data from the Multiwavelength Survey by Yale-Chile (MUSYC), we construct an IRAC-selected catalog, containing photometry in UBVRIz'JHK, [3.6 {mu}m], [4.5 {mu}m], [5.8 {mu}m], and [8.0 {mu}m]. The catalog contains 43,782 sources with S/N >5 at 3.6 {mu}m, 19,993 of which have 13-band photometry. We compare this catalog to the publicly available MUSYC and FIREWORKS catalogs and discuss the differences. Using a high signal-to-noise sub-sample of 3391 sources with ([3.6] + [4.5])/2 < 21.2, we investigate the star formation rate history of massive galaxies out to z {approx} 1.8. We find that at z {approx} 1.8 at least 30% {+-} 7% of the most massive galaxies (M{sub *} >10{sup 11} M{sub sun}) are passively evolving, in agreement with earlier results from surveys covering less area.

  18. RAPID DETERMINATION OF RA-226 IN ENVIRONMENTAL SAMPLES

    SciTech Connect

    Maxwell, S.

    2012-01-03

    A new rapid method for the determination of {sup 226}Ra in environmental samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for emergency response or routine sample analyses. The need for rapid analyses in the event of a Radiological Dispersive Device or Improvised Nuclear Device event is well-known. In addition, the recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid analyses for radionuclides in environmental samples in the event of a nuclear accident. {sup 226}Ra (T1/2 = 1,620 years) is one of the most toxic of the long-lived alpha-emitters present in the environment due to its long life and its tendency to concentrate in bones, which increases the internal radiation dose of individuals. The new method to determine {sup 226}Ra in environmental samples utilizes a rapid sodium hydroxide fusion method for solid samples, calcium carbonate precipitation to preconcentrate Ra, and rapid column separation steps to remove interferences. The column separation process uses cation exchange resin to remove large amounts of calcium, Sr Resin to remove barium and Ln Resin as a final purification step to remove {sup 225}Ac and potential interferences. The purified {sup 226}Ra sample test sources are prepared using barium sulfate microprecipitation in the presence of isopropanol for counting by alpha spectrometry. The method showed good chemical recoveries and effective removal of interferences. The determination of {sup 226}Ra in environmental samples can be performed in less than 16 h for vegetation, concrete, brick, soil, and air filter samples with excellent quality for emergency or routine analyses. The sample preparation work takes less than 6 h. {sup 225}Ra (T1/2 = 14.9 day) tracer is used and the {sup 225}Ra progeny {sup 217}At is used to determine chemical yield via alpha spectrometry. The rapid fusion technique is a rugged sample digestion method that ensures that any

  19. Keck and VLT Observations of Super-Damped Lyman-Alpha Absorbers at z 2- 2.5: Constraints on Chemical Compositions and Physical Conditions

    NASA Astrophysics Data System (ADS)

    Kulkarni, Varsha P.; Som, Debopam; Morrison, Sean; Péroux, Celine; Quiret, Samuel; York, Donald G.

    2015-12-01

    We report Keck/Echellette Spectrograph and Imager and Very Large Telescope/Ultraviolet-Visual Echelle Spectrograph observations of three super-damped Lyα quasar absorbers with H i column densities log NH i ≥ 21.7 at redshifts 2 ≲ z ≲ 2.5. All three absorbers show similar metallicities (˜-1.3 to -1.5 dex), and dust depletion of Fe, Ni, and Mn. Two of the absorbers show supersolar [S/Zn] and [Si/Zn]. We combine our results with those for other damped Lyα a absorbers (DLAs) to examine trends between NH i, metallicity, and dust depletion. A larger fraction of the super-DLAs lie close to or above the line [X/H] = 20.59 - log NH i in the metallicity versus NH i plot, compared to the less gas-rich DLAs, suggesting that super-DLAs are more likely to be rich in molecules. Unfortunately, our data for Q0230-0334 and Q0743+1421 do not cover H2 absorption lines. For Q1418+0718, some H2 lines are covered, but not detected. CO is not detected in any of our absorbers. For DLAs with log NH i < 21.7, we confirm strong correlation between metallicity and Fe depletion, and find a correlation between metallicity and Si depletion. For super-DLAs, these correlations are weaker or absent. The absorbers toward Q0230-0334 and Q1418+0718 show potential detections of weak Lyα emission, implying star formation rates of ˜1.6 and ˜0.7 M⊙ yr-1, respectively (ignoring dust extinction). Upper limits on the electron densities from C ii*/C ii or Si ii*/Si ii are low, but are higher than the median values in less gas-rich DLAs. Finally, systems with log NH i > 21.7 may have somewhat narrower velocity dispersions Δv90 than the less gas-rich DLAs, and may arise in cooler and/or less turbulent gas. Includes observations collected during program ESO 93.A-0422 at the European Southern Observatory (ESO) Very Large Telescope (VLT) with the Ultraviolet-Visual Echelle Spectrograph (UVES) on the 8.2 m telescopes operated at the Paranal Observatory, Chile. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.

  20. KECK AND VLT OBSERVATIONS OF SUPER-DAMPED Lyα ABSORBERS AT z ∼ 2–2.5: CONSTRAINTS ON CHEMICAL COMPOSITIONS AND PHYSICAL CONDITIONS

    SciTech Connect

    Kulkarni, Varsha P.; Som, Debopam; Morrison, Sean; Péroux, Celine; Quiret, Samuel; York, Donald G.

    2015-12-10

    We report Keck/Echellette Spectrograph and Imager and Very Large Telescope/Ultraviolet-Visual Echelle Spectrograph observations of three super-damped Lyα quasar absorbers with H i column densities log N{sub H} {sub i} ≥ 21.7 at redshifts 2 ≲ z ≲ 2.5. All three absorbers show similar metallicities (∼−1.3 to −1.5 dex), and dust depletion of Fe, Ni, and Mn. Two of the absorbers show supersolar [S/Zn] and [Si/Zn]. We combine our results with those for other damped Lyα a absorbers (DLAs) to examine trends between N{sub H} {sub i}, metallicity, and dust depletion. A larger fraction of the super-DLAs lie close to or above the line [X/H] = 20.59 − log N{sub H} {sub i} in the metallicity versus N{sub H} {sub i} plot, compared to the less gas-rich DLAs, suggesting that super-DLAs are more likely to be rich in molecules. Unfortunately, our data for Q0230−0334 and Q0743+1421 do not cover H{sub 2} absorption lines. For Q1418+0718, some H{sub 2} lines are covered, but not detected. CO is not detected in any of our absorbers. For DLAs with log N{sub H} {sub i} < 21.7, we confirm strong correlation between metallicity and Fe depletion, and find a correlation between metallicity and Si depletion. For super-DLAs, these correlations are weaker or absent. The absorbers toward Q0230−0334 and Q1418+0718 show potential detections of weak Lyα emission, implying star formation rates of ∼1.6 and ∼0.7 M{sub ⊙} yr{sup −1}, respectively (ignoring dust extinction). Upper limits on the electron densities from C ii*/C ii or Si ii*/Si ii are low, but are higher than the median values in less gas-rich DLAs. Finally, systems with log N{sub H} {sub i} > 21.7 may have somewhat narrower velocity dispersions Δv{sub 90} than the less gas-rich DLAs, and may arise in cooler and/or less turbulent gas.

  1. How does back muscle strength change after posterior lumbar interbody fusion?

    PubMed

    Lee, Chong-Suh; Kang, Kyung-Chung; Chung, Sung-Soo; Park, Won-Hah; Shin, Won-Ju; Seo, Yong-Gon

    2017-02-01

    OBJECTIVE There is a lack of evidence of how back muscle strength changes after lumbar fusion surgery and how exercise influences these changes. The aim of this study was to evaluate changes in back muscle strength after posterior lumbar interbody fusion (PLIF) and to measure the effects of a postoperative exercise program on muscle strength and physical and mental health outcomes. METHODS This prospective study enrolled 59 women (mean age 58 years) who underwent PLIF at 1 or 2 spinal levels. To assess the effects of a supervised lumbar stabilization exercise (LSE), the authors allocated the patients to an LSE (n = 26) or a control (n = 33) group. The patients in the LSE group performed the LSEs between 3 and 6 months postoperatively. Back extensor strength, visual analog scale (VAS) scores in back pain, and physical component summary (PCS) and mental component summary (MCS) scores on the 36-Item Short Form Health Survey were determined for the both groups. RESULTS Mean strength of the back muscles tended to slightly decrease by 7.5% from preoperatively to 3 months after PLIF (p = 0.145), but it significantly increased thereafter and was sustained until the last follow-up (38.1%, p < 0.001). The mean back muscle strength was similar in the LSE and control groups preoperatively, but it increased significantly more in the LSE group (64.2%) than in the control group (21.7%) at the last follow-up 12 months after PLIF (p = 0.012). At the last follow-up, decreases in back pain VAS scores were more significant among LSE group patients, who had a pain reduction on average of 58.2%, than among control group patients (reduction of 26.1%) (p = 0.013). The patients in the LSE group also had greater improvement in both PCS (39.9% improvement) and MCS (20.7% improvement) scores than the patients in the control group (improvement of 18.0% and 1.1%, p = 0.042 and p = 0.035, respectively). CONCLUSIONS After PLIF, strength in back muscles decreased until 3 months postoperatively but significantly increased after that period. The patients who regularly underwent postoperative LSE had significantly improved back strength, less pain, and less functional disability at 12 months postoperatively.

  2. Determination the total neutron yields of several semiconductor compounds using various alpha emitters

    NASA Astrophysics Data System (ADS)

    Abdullah, Ramadhan Hayder; Sabr, Barzan Nehmat

    2016-03-01

    In the present work, the cross-sections of (α,n) reactions available in the literature as a function of α-particle energies for light and medium elements have been rearranged for α-particle energies from near threshold up to 10 MeV in steps of (0.050MeV) using the (Excel and Matlab) computer programs. The obtained data were used to calculate the neutron yields (n/106α) using the quick basic-computer program (Simpson Rules). The stopping powers of alpha particle energies from near threshold to 10 MeV for light and medium elements such as (nat.Be,10B,11B,13C,14N,nat.O,nat.F,nat.Mg,nat.Al,29Si,30Si, nat.P and 46.48Ti) have been calculated using the Zeigler formula. The kinetic energies (Tα) and the branching ratios of each α-emitters such as (211Bi, 210Po, 211Po, 215Po, 217At, 218Rn, 219Rn, 222Rn, 224Ra, 226Ra, 215Th, 228Th, 232U, 234U, 236U, 238U, 238Pu, 239Pu, 241Am, 245Es, 252Fm, 254Fm, 256Fm, 257Fm and 257Md) are taken into consideration to calculate the mean kinetic energy . The polynomial expressions were used to fitting the calculated weighted average of neutron yields (n/106α) for natural light and medium elements such as (Be, B, C, N, O, F, Mg, Al, Si, P and Ti) to determine the adopted neutron yields from the best fitting equation with minimum (CHISQ) at mean kinetic energies of various α-emitters. The total neutron yields (n/s/gx/ppmi) of the mentioned natural light and medium elements have been calculated using the adopted neutron yields (n/106α) from the fitting equations at mean kinetic energies of various α-emitters. The total neutron yields (n/s/gα-emitters/gcompounds) of semiconductor compounds such as (AlN, AlP, BN, BP, SiC, TiO2, BeSiN2, MgCN2, MgSiN2 and MgSiP2) have been calculated by mixing (1gram) of compounds with (1gram) of pure α-emitters using the quick basic computer program. The aim of the present work is to constructed and fabricate the neutron sources theoretically

  3. Effects of Ionizing Radiation on Murine Gene Expression in Skin and Bone

    NASA Technical Reports Server (NTRS)

    Terada, Masahiro; Schreurs, Ann-Sofie; Shirazi-Fard, Yasaman; Alwood, Joshua; Tahimic, Candice; Sowa, Marianne B.; Globus, Ruth K.

    2017-01-01

    Long duration spaceflight causes a negative calcium balance and reduces bone density in astronauts. The potential for exposure to space radiation to contribute to lasting decrements in bone mass is not yet understood. Sustained changes to bone mass have a relatively long latency for development, however skin is a radiation sensitive organ and changes in skin gene expression may serve as an early radiation biomarker of exposures and may correlate with adverse effects on skeletal tissue. Previous studies have shown that FGF18 gene expression levels of hair follicles collected from astronauts on the ISS rose over time. In the hair follicle, FGF18 signaling mediates radioresistance in the telogen by arresting the cell cycle, and FGF18 has the potential to function as a radioprotector. In bone, FGF18 appears to regulate cell proliferation and differentiation positively during osteogenesis and negatively during chondrogenesis. Cellular defense responses to radiation are shared by a variety of organs, hence in this study, we examined whether radiation induced gene expression changes in skin may be predictive of the responses of skeletal tissue to radiation exposure. We have examined oxidative stress and growth arrest pathways in mouse skin and long bones by measuring gene expression levels via quantitative polymerase chain reaction (qPCR) after exposure to total body irradiation (TBI). To investigate the effects of irradiation on gene expression, we used skin and femora (cortical shaft) from the following treatment groups: control (normally loaded, sham-irradiated), and TBI (0.5 Gy Fe-56 600 MeV/n and 0.5 Gy H-1 150 MeV/n). Animals were euthanized one and 11 days post-IR. Statistical analysis was performed via a Student's ttest. In skin samples one day after IR, skin expression of FGF18 was significantly greater (3.8X) than sham-irradiated controls (3.8X), but did not differ 11 days post TBI. Expression levels of other radiation related genes (Nfe2l2, Trp53, Cdkn1a, FoxO3, Gadd45g, SOD1), was not different due to TBI at either time point. In bone (femora) TBI significantly increased (3.8X) expression of the pro-bone resorption cytokine, MCP-1, one day after TBI. FGF18 expression in skin and MCP- 1 expression in bone were found to be positively correlated (P less than 0.002, r=0.8779). Further, microcomputed tomography analysis of tibae from these animals showed reduced fractional cancellous bone volume (-21.7%) at 11 days post exposure. These results suggest that early radiation induced changes in FGF18 gene expression in skin may have value for predicting subsequent loss of cancellous bone mass.