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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. Polarization potentials for the 208Pb(7Li,6Li)209Pb transfer

    NASA Astrophysics Data System (ADS)

    Keeley, N.; Rusek, K.

    1997-12-01

    Recent optical model analyses of near-barrier 7Li+208Pb elastic scattering data found a peak in the energy dependence of WOM, the strength of the imaginary part of the optical model potential at the strong absorption radius. It was speculated that this might be due to the polarization potentials produced by couplings to the 208Pb(7Li,6Li)209Pb transfer channels. In this Brief Report we show explicitly that such couplings do indeed produce polarization potentials with the same energy dependence as that observed for the empirical optical potentials.

  4. Measurement of 208Pb(n ,γ )209Pb Maxwellian averaged neutron capture cross section

    NASA Astrophysics Data System (ADS)

    Weissman, L.; Tessler, M.; Arenshtam, A.; Eliyahu, I.; Halfon, S.; Guerrero, C.; Kaizer, B.; Kijel, D.; Kreisel, A.; Palchan, T.; Paul, M.; Perry, A.; Schimel, G.; Silverman, I.; Shor, A.; Tamim, N.; Vaintraub, S.

    2017-07-01

    The doubly magic 208Pb nucleus is a bottleneck at the termination of the s -process path due to its very low neutron capture cross section. This cross section is also important for the decomposition of s , r processes and U/Th radiogenic decay contributions to the Pb-Bi solar abundances. The 208Pb(n ,γ )209Pb cross section was measured at the Soreq Applied Research Accelerator Facility Phase I using an intense quasi-Maxwellian neutron source produced by irradiation of the liquid-lithium target with a 1.5-mA continuous-wave proton beam at 1.94 MeV. The cross section was measured by counting the β activity from the irradiated lead target. The measurement allowed us to evaluate the Maxwellian averaged cross section (MACS) at 30 keV obtaining a value of 0.33(2) mb. This has been compared with the earlier activation and time-of-flight measurements found in the literature. The MACS cross-sectional value of the 63Cu(n ,γ )64Cu reaction was determined in the same experiment and is compared to a recent published value.

  5. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. 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.

  7. Alpha spectroscopy of nuclides produced in the interaction of 5 GeV protons with heavy element targets

    NASA Astrophysics Data System (ADS)

    Bowman, J. David; Eppley, Richard E.; Hyde, Earl K.

    1982-02-01

    Alpha particle energies were redetermined to an accuracy of 2 to 5 keV for a group of 40 neutron-deficient nuclides with atomic numbers ranging from 65 to 88. Improved half-life values were measured for 10 of these nuclides. Weightless samples containing mixtures of these activities were prepared by use of the helium jet transport technique to remove spallation and fragmentation products recoiling from targets of U, Th, Au, and Ta bombarded with 5 GeV protons. Experimental and calibration techniques are discussed in detail. Implications of the results for the mechanism of reaction of 5 GeV protons with complex targets are briefly discussed. RADIOACTIVITY 5 GeV p + U, Th, Au, Ta; separated recoil products by helium jet; measured Eα, t12 151Dy, 154Er, 150Dy, 152Ho, 152Hom, 151Ho, 151Hom, 153Er, 152Er, 154Tm, 154Tmm, 153Tm, 179Pt, 155Yb, 178Pt, 177Pt, 176Pt, 199Pom, 198Po, 212Fr, 197Pom, 213Fr, 212Ra; measured Eα 149Tb, 211At, 204Fr, 222Ac, 217At, 218Rn, 219Fr, 211Po, 214Po, 217Rn, 216At, 218Fr, 215At, 213Po, 212Po, 214At, 211Pom; reaction mechanisms discussed.

  8. Antioxidant and gene expression responses of Eisenia fetida following repeated exposure to BDE209 and Pb in a soil-earthworm system.

    PubMed

    Hu, Shuangqing; Zhang, Wei; Li, Jing; Lin, Kuangfei; Ji, Rong

    2016-06-15

    This study first adopted repeated treatment model to investigate stress responses in earthworms (Eisenia fetida) following exposure to decabromodiphenyl ether (BDE209) and lead (Pb), which are the mainly co-existed contaminants at e-waste recycling sites. We evaluated the impacts of BDE209-Pb on antioxidative enzyme (superoxide dismutase, SOD; catalase, CAT) activities, malondialdehyde (MDA) contents and transcriptional levels of three target genes (SOD, CAT and Hsp70), and further explored the relationships among these biomarkers. Results demonstrated that almost all the parameters were generally induced and the responses followed certain dose-effect relationships. Compared to the controls, a significant (P<0.05) up-regulation trend of expression levels of the three genes could be clearly observed after 14days incubation. Additionally, there existed good correlations between target genes expression levels and antioxidant enzyme activities (R>0.64). The observations could provide important information of ecotoxicological effects of BDE209-Pb in a soil-earthworm system as well as the mechanism of antioxidant defense. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. Detection of Histomonas meleagridis in turkeys cecal droppings by PCR amplification of the small subunit ribosomal DNA sequence.

    PubMed

    Huber, Karine; Chauve, C; Zenner, L

    2005-08-10

    Histomonas meleagridis is a protozoan parasite that may cause histomoniasis, a disease of gallinaceous fowl characterized by necrotic typhlitis, hepatitis and high mortality. Diagnosis of this disease is based on direct identification or on cultivation of the parasite. With the aim of developing more sensitive, rapid and useful tools for parasite detection, PCR that amplified a DNA target of 209 pb of the 18S rRNA gene was designed to detect the genome of H. meleagridis and to differentiate it from the genome of Tetratrichomonas gallinarum, another common protozoan parasite of fowl. The sensitivity of the test was evaluated using serial diluted samples of cultured H. meleagridis and showed positive amplification for concentrations comprised between 10 and 10(-1)parasites/ml of culture. The sensitivity for cecal droppings samples was assessed using spiked material and was comprised between 3 x 10(3) and 3 x 10(5)parasites/ml of stool. The reliability of the PCR for the detection of Histomonas infection was also evaluated by experimental infection of turkeys. Results of the PCR appeared to be in agreement with the development of the clinical signs and of the cecal lesions. The PCR developed in this study may be a useful tool in the detection and identification of H. meleagridis for rapid, routine screening as a supplement to direct identification or cultivation of the parasite.

  18. Nucleosynthesis at the termination point of the s process

    NASA Astrophysics Data System (ADS)

    Ratzel, U.; Arlandini, C.; Käppeler, F.; Couture, A.; Wiescher, M.; Reifarth, R.; Gallino, R.; Mengoni, A.; Travaglio, C.

    2004-12-01

    Stellar cross sections of importance with respect to the termination of the s -process reaction chain have been determined for the two cases, 208Pb (n,γ) 209Pb and 209Bi (n,γ) 210Big , yielding kT=30 keV values of <σv> / vT =0.31±0.2 mb and 2.54±0.14 mb , respectively. The measurements were carried out by activation of Pb and Bi samples in a quasistellar neutron spectrum using gold as a cross section standard. With this technique the uncertainties reported in previous works could be considerably reduced. The measurements are complemented by a discussion of the recycling at the termination point of the s -process neutron capture chain in a 3 M⊙ and [Fe/H] =-1.3 asymptotic giant branch star. At this metallicity, AGB stars give rise to the maximum production of s -process lead. The sensitivity of the isotopic lead abundances is discussed with respect to the remaining cross section uncertainties. The information obtained in this work is also of relevance for an assessment of the α activity due to a buildup of 210Po in Pb/Bi cooled fast reactor systems.

  19. 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

  20. 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.

  1. Enhanced soil washing process for the remediation of PBDEs/Pb/Cd-contaminated electronic waste site with carboxymethyl chitosan in a sunflower oil-water solvent system and microbial augmentation.

    PubMed

    Ye, Mao; Sun, Mingming; Wan, Jinzhong; Fang, Guodong; Li, Huixin; Hu, Feng; Jiang, Xin; Kengara, Fredrick Orori

    2015-02-01

    An innovative ex situ soil washing technology was developed to remediate polybrominated diphenyl ethers (PBDEs) and heavy metals in an electronic waste site. Elevated temperature (50 °C) in combination with ultrasonication (40 kHz, 20 min) at 5.0 mL L(-1) sunflower oil and 2.5 g L(-1) carboxymethyl chitosan were found to be effective in extracting mixed pollutants from soil. After two successive washing cycles, the removal efficiency rates for total PBDEs, BDE28, BDE47, BDE209, Pb, and Cd were approximately 94.1, 93.4, 94.3, 99.1, 89.3, and 92.7 %, respectively. Treating the second washed soil with PBDE-degrading bacteria (Rhodococcus sp. strain RHA1) inoculation and nutrient addition for 3 months led to maximum biodegradation rates of 37.3, 52.6, 23.9, and 1.3 % of the remaining total PBDEs, BDE28, BDE47, BDE209, respectively. After the combined treatment, the microbiological functions of washed soil was partially restored, as indicated by a significant increase in the counts, biomass C, N, and functioning diversity of soil microorganisms (p < 0.05), and the residual PBDEs and heavy metals mainly existed as very slow desorbing fractions and residual fractions, as evaluated by Tenax extraction combined with a first-three-compartment model and sequential extraction with metal stability indices (I R and U ts). Additionally, the secondary environmental risk of mixed contaminants in the remediated soil was limited. Therefore, the proposed combined cleanup strategy is an environment-friendly technology that is important for risk assessment and management in mixed-contaminated sites.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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

  7. Doubly magic 208Pb: High-spin states, isomers, and E 3 collectivity in the yrast decay

    NASA Astrophysics Data System (ADS)

    Broda, R.; Janssens, R. V. F.; Iskra, Ł. W.; Wrzesinski, J.; Fornal, B.; Carpenter, M. P.; Chiara, C. J.; Cieplicka-Oryńczak, N.; Hoffman, C. R.; Kondev, F. G.; Królas, W.; Lauritsen, T.; Podolyak, Zs.; Seweryniak, D.; Shand, C. M.; Szpak, B.; Walters, W. B.; Zhu, S.; Brown, B. A.

    2017-06-01

    Yrast and near-yrast levels up to spin values in excess of I =30 ℏ have been delineated in the doubly magic 208Pb nucleus following deep-inelastic reactions involving 208Pb targets and, mostly, 430-MeV 48Ca and 1440-MeV 208Pb beams. The level scheme was established up to an excitation energy of 16.4 MeV, based on multifold γ-ray coincidence relationships measured with the Gammasphere array. Below the well-known, 0.5-μs 10+ isomer, ten new transitions were added to earlier work. The delineation of the higher parts of the level sequence benefited from analyses involving a number of prompt- and delayed-coincidence conditions. Three new isomeric states were established along the yrast line with Iπ=20- (10 342 keV), 23+ (11 361 keV), and 28- (13 675 keV), and respective half-lives of 22(3), 12.7(2), and 60(6) ns. Gamma transitions were also identified preceding in time the 28- isomer; however, only a few could be placed in the level scheme and no firm spin-parity quantum numbers could be proposed. In contrast, for most states below this 28- isomer, firm spin-parity values were assigned, based on total electron-conversion coefficients, deduced for low-energy (<500 keV ) transitions from γ-intensity balances, and on measured γ-ray angular distributions. The latter also enabled the quantitative determination of mixing ratios. The transition probabilities extracted for all isomeric transitions in 208Pb have been reviewed and discussed in terms of the intrinsic structure of the initial and final levels involved. Particular emphasis was placed on the many observed E 3 transitions as they often exhibit significant enhancements in strength [of the order of tens of Weisskopf units (W.u.)] comparable to the one seen for the neutron j15 /2→g9 /2 E 3 transition in 209Pb. In this context, the enhancement of the 725-keV E 3 transition (56 W.u.) associated with the decay of the highest-lying 28- isomer observed in this work remains particularly challenging to explain. Large

  8. Doubly magic Pb208 : High-spin states, isomers, and E3 collectivity in the yrast decay

    DOE PAGES

    Broda, R.; Janssens, R. V. F.; Iskra, Ł. W.; ...

    2017-06-12

    Yrast and near-yrast levels up to spin values in excess of I = 30h have been delineated in the doubly-magic 208Pb nucleus following deep-inelastic reactions involving 208Pb targets and, mostly, 430-MeV 48Ca and 1440-MeV 208Pb beams. The level scheme was established up to an excitation energy of 16.4 MeV, based on multi-fold γ-ray coincidence relationships measured with the Gammasphere array. Below the well-known, 0.5-μs 10+ isomer, ten new transitions were added to earlier work. The delineation of the higher parts of the level sequence benefited from analyses involving a number of prompt- and delayed-coincidence conditions. Three new isomeric states weremore » established along the yrast line with I π = 20- (10342 keV), 23+ (11361 keV), and 28- (13675 keV), and respective half-lives of 22(3), 12.7(2), and 60(6) ns. Gamma transitions were also identified preceding in time the 28- isomer, however, only a few could be placed in the level scheme and no firm spin-parity quantum numbers could be proposed. In contrast, for most states below this 28- isomer, firm spin-parity values were assigned, based on total electron-conversion coefficients, deduced for low-energy (<500 keV) transitions from γ-intensity balances, and on measured γ-ray angular distributions. The latter also enabled the quantitative determination of mixing ratios. The transition probabilities extracted for all isomeric transitions in 208Pb have been reviewed and discussed in terms of the intrinsic structure of the initial and final levels involved. Particular emphasis was placed on the many observed E3 transitions as they often exhibit significant enhancements in strength (of the order of tens of W.u.) comparable to the one seen for the neutron j15/2→g9/2 E3 transition in 209Pb. In this context, the enhancement of the 725-keV E3 transition (56 W.u.) associated with the decay of the highest-lying 28- isomer observed in this work remains particularly challenging to explain. Large-scale shell

  9. 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

  10. Digital breast tomosynthesis versus supplemental diagnostic mammographic views for evaluation of noncalcified breast lesions.

    PubMed

    Zuley, Margarita L; 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

    To compare the diagnostic performance of breast tomosynthesis versus supplemental mammography views in classification of masses, distortions, and asymmetries. 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. 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 1160) to 48% (559 of 1160) for cases rated BI

  11. 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.

  12. Analyses of antibacterial activity and cell compatibility of titanium coated with a Zr-C-N film.

    PubMed

    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

    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. Reactive nitrogen gas (N(2)) with and without acetylene (C(2)H(2)) 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. 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. High-C-content Zr-C-N coatings not only provide short-term antibacterial activity against S. aureus but are also biocompatible with HGF cells.

  13. Enhancement of docosahexaenoic acid synthesis by manipulation of antioxidant capacity and prevention of oxidative damage in Schizochytrium sp.

    PubMed

    Ren, Lu-Jing; Sun, Xiao-Man; Ji, Xiao-Jun; Chen, Sheng-Lan; Guo, Dong-Sheng; Huang, He

    2017-01-01

    Oxygen-mediated cell damage is an important issue in aerobic fermentation. In order to counteract these problems, effect of ascorbic acid on cell growth and docosahexaenoic acid (DHA) production was investigated in Schizochytrium sp. Addition of 9g/L ascorbic acid resulted in 16.16% and 30.44% improvement in cell dry weight (CDW) and DHA yield, respectively. Moreover, the total antioxidant capacity (T-AOC) of cells decreased from 2.17 at 12h to 0 at 60h and did not recover, while ascorbic acid addition could extend the time of arrival zero with the reduced intracellular ROS. However, ROS levels still increased after 72h. Therefore, to further solve the problem of high ROS levels and low T-AOC of cells after 72h, a two-point addition strategy was proposed. With this strategy, DHA yield was further increased to 38.26g/L. This work innovatively investigated the feasibility of manipulating Schizochytrium sp. cultivation through ROS level and T-AOC. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. 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.

  15. 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.

  16. 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.

  17. Assessing the Availability of Healthier Children's Meals at Leading Quick-Service and Full-Service Restaurants.

    PubMed

    Sliwa, Sarah; Anzman-Frasca, Stephanie; Lynskey, Vanessa; Washburn, Kyle; Economos, Christina

    2016-04-01

    To compare the calorie, fat, saturated fat, and sodium content of available children's meal combinations in leading restaurants with national recommendations. Cross-sectional. Children's menu offerings and corresponding nutrition information were collected (May, 2014) from Web sites of the top 10 quick-service (QSR) and top 10 full-service (FSR) restaurant chains that offered a children's menu and provided nutrition information. Total calories (kcal), percent calories from fat and saturated fat, and total sodium (mg) were calculated for children's meal combinations (QSR N = 1,363; FSR N = 6,654). Combinations with ≤ 600 kcal, ≤ 35% kcal from fat, ≤ 10% kcal from saturated fat, ≤ 770 mg sodium, and those that met all 4 of these criteria were identified. Frequencies by restaurant segment. The majority of QSR (72%) and FSR (63%) meal combinations had ≤ 600 kcal. Only 31.9% of combinations at QSRs and 21.7% at FSRs met all 4 criteria. In both segments the calorie target was most frequently met, and the sodium target the least. Children's meal combinations with ≤ 600 kcal are available at leading restaurant chains, but many meals fail to meet current national recommendations for fat, saturated fat, and sodium. Menu labeling legislation may address caloric content but implications for other nutrients remain unclear. Copyright © 2016 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  18. Cross-sectional study of malocclusion in Spanish children.

    PubMed

    Almerich-Silla, José-Manuel; Montiel-Company, José-María; Bellot-Arcís, Carlos; Puertes-Fernández, Neus

    2014-01-01

    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. 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. 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. Approximately 20% of the children needed orthodontic treatment. Neither gender nor social class appeared to exert a significant influence on orthodontic treatment need.

  19. 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

  20. Risk factors for persistent cervical intraepithelial neoplasia grades 1 and 2: managed by watchful waiting.

    PubMed

    Ho, Gloria Y F; Einstein, Mark H; Romney, Seymour L; Kadish, Anna S; Abadi, Maria; Mikhail, Magdy; Basu, Jayasri; Thysen, Benjamin; Reimers, Laura; Palan, Prabhudas R; Trim, Shelly; Soroudi, Nafisseh; Burk, Robert D

    2011-10-01

    : This study examines risk factors for persistent cervical intraepithelial neoplasia (CIN) and examines whether human papillomavirus (HPV) testing predicts persistent lesions. : Women with histologically diagnosed CIN 1 or CIN 2 (n = 206) were followed up every 3 months without treatment. Human papillomavirus genotyping, plasma levels of ascorbic acid, and red blood cell folate levels were obtained. Cervical biopsy at 12 months determined the presence of CIN. Relative risk (RR) was estimated by log-linked binomial regression models. : At 12 months, 70% of CIN 1 versus 54% of CIN 2 lesions spontaneously regressed (p < .001). Levels of folate or ascorbic acid were not associated with persistent CIN at 12 months. Compared with HPV-negative women, those with multiple HPV types (RRs ranged from 1.68 to 2.17 at each follow-up visit) or high-risk types (RRs range = 1.74-2.09) were at increased risk for persistent CIN; women with HPV-16/18 had the highest risk (RRs range = 1.91-2.21). Persistent infection with a high-risk type was also associated with persistent CIN (RRs range = 1.50-2.35). Typing for high-risk HPVs at 6 months only had a sensitivity of 46% in predicting persistence of any lesions at 12 months. : Spontaneous regression of CIN 1 and 2 occurs frequently within 12 months. Human papillomavirus infection is the major risk factor for persistent CIN. However, HPV testing cannot reliably predict persistence of any lesion.

  1. 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

    2017-04-26

    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.

  2. 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

  3. A new structure of p-GaN/InGaN heterojunction to enhance hole injection for blue GaN-based LEDs

    NASA Astrophysics Data System (ADS)

    Lin, Zhiting; Wang, Haiyan; Lin, Yunhao; Yang, Meijuan; Li, Guoqiang; Xu, Bingshe

    2016-07-01

    A new structure of p-GaN/InGaN heterojunction has been proposed to enhance hole injection for blue GaN-based light-emitting diodes (LEDs). It is demonstrated by the simulation results that a p-GaN (50 nm)/In0.05Ga0.95N (150 nm) heterojunction can make a 25% and 10% increment of hole and electron concentration in the active region, respectively, finally resulting in a 55% improvement on the LED’s radiative recombination intensity. The simulation also reveals that the efficiency droop is alleviated from 32.9% to 21.7% at the current density of 100 A cm-2. The enhanced hole injection is mainly attributed to the increased average background hole concentration of the area between the p-AlGaN electron blocking layer (EBL) to the p-GaN/InGaN heterojunction. The increasing potential barrier of the conduction band, resulting from the introduction of p-GaN/InGaN heterojunction, would also weaken electron leakage and is favorable to the LED’s luminous performance. The experimental results show that the wall-plug efficiency (WPE) of the p-GaN/InGaN LED increases by 26.0% at the injection current of 75 mA, in spite of the increasing electric resistance, which impairs the improvement of the LED’s performance from the enhanced hole injection. The structure of the p-GaN/InGaN heterojunction is novel in the field of p-type region design, and is a simple but effective way to promote the LED’s performance, which is very promising for application in further high-performance LED fabrication.

  4. One-Year Evolution of Behavioral and Psychological Symptoms of Dementia in Patients Initially Hospitalized in Cognitive Behavioral Units: The EVITAL Prospective Cohort.

    PubMed

    Rouch, Isabelle; Pongan, Elodie; Trombert, Béatrice; Fabre, Florence; Auguste, Nicolas; Sellier, Claire; Freulon, Magalie; Jacqueline, Sophie; Federico, Denis; Mouchoux, Christelle; Martin-Gaujard, Géraldine; Krolak-Salmon, Pierre; Laurent, Bernard; Dorey, Jean-Michel

    2017-01-01

    The 2008-2012 French Alzheimer's Plan has provided hospital Cognitive and Behavioral Units (CBU) to improve the management of patients with productive behavioral and psychological symptoms of dementia (BPSD). Little is known concerning the behavioral outcome of these patients after discharge. The present study investigated the long-term evolution of BPSD over one year after CBU discharge. The EVITAL cohort included 221 participants admitted to the CBUs of 3 French hospitals. BPSD were collected using the Neuropsychiatric Inventory (NPI) at admission and 3, 6, and 12 months after hospitalization. The global NPI score evolution was assessed using a linear mixed-effect model. A four-factor model of the NPI including behavioral dyscontrol, psychosis, mood, and agitation subscores was also analyzed. Our analysis focused on 148 patients followed up during 12 months and evaluated at each visit. The global NPI score was 48.5 (SD 21.7) at baseline, 28.8 (SD 18.7) at 3-month, 23.2 (SD 16.4) at 6-month and 20.9 (SD 15.9) at 12-month follow-up. The score significantly decreased from baseline to follow-up (F = 109.3 p < 0.0001). Moreover, the decrease was observed for each NPI subscores. The Clinical Dementia Rating (CDR) scale score was significantly linked to the baseline NPI score (t = 2.76, p = 0.009). Conversely, the NPI decline was observed whatever the CDR level. The present study showed a decrease in the global NPI score and all its subscores during the year following the CBU hospitalization, regardless of the initial CDR score.

  5. Problem-Solving Therapy and Supportive Therapy in Older Adults With Major Depression and Executive Dysfunction

    PubMed Central

    Areán, Patricia A.; Raue, Patrick; Mackin, R. Scott; Kanellopoulos, Dora; McCulloch, Charles; Alexopoulos, George S.

    2010-01-01

    Objective The purpose of this study was to determine whether problem-solving therapy is an effective treatment in older patients with depression and executive dysfunction, a population likely to be resistant to antidepressant drugs. Method Participants were adults age 60 and older with major depression and executive dysfunction. Problem-solving therapy was modified to be accessible to this population. Participants were randomly assigned to 12 weekly sessions of problem-solving therapy or supportive therapy and assessed at weeks 3, 6, 9, and 12. Results Of the 653 individuals referred for this study, 221 met selection criteria and were enrolled in the study. Reduction of depressive symptom severity was comparable for the two treatment groups during the first 6 weeks of treatment, but at weeks 9 and 12 the problem-solving therapy group had a greater reduction in symptom severity, a greater response rate, and a greater remission rate than the supportive therapy group (response rates at week 9: 47.1% and 29.3%; at week 12: 56.7% and 34.0%; remission rates at week 9: 37.9% and 21.7%; at week 12: 45.6% and 27.8%). Problem-solving therapy yielded one additional response or remission over supportive therapy for every 4.4–5.6 patients by the end of the trial. Conclusions These results suggest that problem-solving therapy is effective in reducing depressive symptoms and leading to treatment response and remission in a considerable number of older patients with major depression and executive dysfunction. The clinical value of this finding is that problem-solving therapy may be a treatment alternative in an older patient population likely to be resistant to pharmacotherapy. PMID:20516155

  6. Problem-solving therapy and supportive therapy in older adults with major depression and executive dysfunction.

    PubMed

    Areán, Patricia A; Raue, Patrick; Mackin, R Scott; Kanellopoulos, Dora; McCulloch, Charles; Alexopoulos, George S

    2010-11-01

    The purpose of this study was to determine whether problem-solving therapy is an effective treatment in older patients with depression and executive dysfunction, a population likely to be resistant to antidepressant drugs. Participants were adults age 60 and older with major depression and executive dysfunction. Problem-solving therapy was modified to be accessible to this population. Participants were randomly assigned to 12 weekly sessions of problem-solving therapy or supportive therapy and assessed at weeks 3, 6, 9, and 12. Of the 653 individuals referred for this study, 221 met selection criteria and were enrolled in the study. Reduction of depressive symptom severity was comparable for the two treatment groups during the first 6 weeks of treatment, but at weeks 9 and 12 the problem-solving therapy group had a greater reduction in symptom severity, a greater response rate, and a greater remission rate than the supportive therapy group (response rates at week 9: 47.1% and 29.3%; at week 12:56.7% and 34.0%; remission rates at week 9: 37.9% and 21.7%; at week 12: 45.6% and 27.8%). Problem-solving therapy yielded one additional response or remission over supportive therapy for every 4.4-5.6 patients by the end of the trial. These results suggest that problem-solving therapy is effective in reducing depressive symptoms and leading to treatment response and remission in a considerable number of older patients with major depression and executive dysfunction. The clinical value of this finding is that problem-solving therapy may be a treatment alternative in an older patient population likely to be resistant to pharmacotherapy.

  7. Cross-sectional survey of treatment practices for urethritis at pharmacies, private clinics and government health facilities in coastal Kenya: many missed opportunities for HIV prevention.

    PubMed

    Mugo, Peter M; Duncan, Sarah; Mwaniki, Samuel W; Thiong'o, Alexander N; Gichuru, Evanson; Okuku, Haile Selassie; van der Elst, Elise M; Smith, Adrian D; Graham, Susan M; Sanders, Eduard J

    2013-11-01

    While bacterial sexually transmitted infections (STIs) are important cofactors for HIV transmission, STI control has received little attention in recent years. The aim of this study was to assess STI treatment and HIV testing referral practices among health providers in Kenya. In 2011 we assessed quality of case management for male urethritis at pharmacies, private clinics and government health facilities in coastal Kenya using simulated visits at pharmacies and interviews at pharmacies and health facilities. Quality was assessed using Ministry of Health guidelines. Twenty (77%) of 26 pharmacies, 20 (91%) of 22 private clinics and all four government facilities in the study area took part. The median (IQR) number of adult urethritis cases per week was 5 (2-10) at pharmacies, 3 (1-3) at private clinics and 5 (2-17) at government facilities. During simulated visits, 10% of pharmacies prescribed recommended antibiotics at recommended dosages and durations and, during interviews, 28% of pharmacies and 27% of health facilities prescribed recommended antibiotics at recommended dosages and durations. Most regimens were quinolone-based. HIV testing was recommended during 10% of simulated visits, 20% of pharmacy interviews and 25% of health facility interviews. In an area of high STI burden, most men with urethritis seek care at pharmacies and private clinics. Most providers do not comply with national guidelines and very few recommend HIV testing. In order to reduce the STI burden and mitigate HIV transmission, there is an urgent need for innovative dissemination of up-to-date guidelines and inclusion of all health providers in HIV/STI programmes.

  8. Dynamical Cluster-decay Model (DCM) applied to 9Li+208Pb reaction

    NASA Astrophysics Data System (ADS)

    Kaur, Arshdeep; Hemdeep; Kaushal, Pooja; Behera, Bivash R.; Gupta, Raj K.

    2017-10-01

    The decay mechanism of 217At* formed in 9Li+208Pb reaction is studied within the dynamical cluster-decay model (DCM) at various center-of-mass energies. The aim is to see the behavior of a light neutron-rich radioactive beam on a doubly-magic target nucleus for the (total) fusion cross section σfus and the individual decay channel cross sections. Experimentally, only the isotopic yield of heavy mass residues 211-214At * [equivalently, the light-particles (LPs) evaporation residue cross sections σxn for x = 3- 6 neutrons emission] are measured, with the fusion-fission (ff) component σff taken zero. For a fixed neck-length parameter ΔR, the only parameter in the DCM, we are able to fit σfus =∑x=16σxn almost exactly for 9Li on 208Pb at all E c . m .'s. However, the observed individual decay channels (3n-6n) are very poorly fitted, with unobserved channels (1n, 2n) and σff strongly over-estimated. Different ΔR values, meaning thereby different reaction time scales, are required to fit individually both the observed and unobserved evaporation residue channels (1n-6n) and σff, but then the compound nucleus (CN) contribution σCN is very small (< 1%), and the non-compound nucleus (nCN) decay cross section σnCN contributes the most towards total σfus (=σCN +σnCN). Thus, the 9Li induced reaction on doubly-magic 208Pb is more of a quasi-fission-like nCN decay, which is further analyzed in terms of the statistical CN formation probability PCN and CN survival probability Psurv. For the reaction under study, PCN < < 1 and Psurv → 1, in particular at above barrier energies.

  9. Rehabilitation of hand function after spinal cord injury using a novel handgrip device: a pilot study.

    PubMed

    Hoffman, Haydn; Sierro, Tiffany; Niu, Tianyi; Sarino, Melanie E; Sarrafzadeh, Majid; McArthur, David; Edgerton, V Reggie; Lu, Daniel C

    2017-03-21

    Activity-based therapy (ABT) for patients with spinal cord injury (SCI), which consists of repetitive use of muscles above and below the spinal lesion, improves locomotion and arm strength. Less data has been published regarding its effects on hand function. We sought to evaluate the effects of a weekly hand-focused therapy program using a novel handgrip device on grip strength and hand function in a SCI cohort. Patients with SCI were enrolled in a weekly program that involved activities with the MediSens (Los Angeles, CA) handgrip. These included maximum voluntary contraction (MVC) and a tracking task that required each subject to adjust his/her grip strength according to a pattern displayed on a computer screen. For the latter, performance was measured as mean absolute accuracy (MAA). The Spinal Cord Independence Measure (SCIM) was used to measure each subject's independence prior to and after therapy. Seventeen patients completed the program with average participation duration of 21.3 weeks. The cohort included patients with American Spinal Injury Association (ASIA) Impairment Scale (AIS) A (n = 12), AIS B (n = 1), AIS C (n = 2), and AIS D (n = 2) injuries. The average MVC for the cohort increased from 4.1 N to 21.2 N over 20 weeks, but did not reach statistical significance. The average MAA for the cohort increased from 9.01 to 21.7% at the end of the study (p = .02). The cohort's average SCIM at the end of the study was unchanged compared to baseline. A weekly handgrip-based ABT program is feasible and efficacious at increasing hand task performance in subjects with SCI.

  10. 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.

  11. Microchannel plate detector detection efficiency to monoenergetic electrons between 3 and 28 keV

    NASA Astrophysics Data System (ADS)

    Blase, Ryan C.; Benke, Roland R.; Miller, Gregory P.; Pickens, Keith S.; Waite, J. Hunter

    2017-05-01

    An unshielded microchannel plate (MCP) detector with an ultrafine pore diameter of 2 μm was irradiated by an electron beam to determine the detection efficiency of electrons for creating detector signals, or counts. Tested electron energies spanned a range of 3 kiloelectron volts (keV) to 28 keV. Higher detection efficiencies were measured at the lower end of this energy range, 0.376 counts per incident electron at 3 keV down to 0.155 at 15 keV with an increase to 0.217 at 18 keV and then another decrease down to 0.15 counts per incident electron at 28 keV. The increase at 18 keV is attributed to primary electron interaction with the L shell electrons of lead (Pb), leading to an increase in secondary electron and X-ray generation within the MCP and thus an increase in detection efficiency. For the electron beam directed normal to the MCP surface, the lowest efficiency of 0.15 counts per incident electron was observed at 28 keV. Detection efficiency was also tested as a function of incident angle with angular steps of 5°. Detection efficiency was more sensitive to the angle of incidence as the incident electron energy decreased. The detection efficiency at 3 keV decreased from 0.376 counts per electron at the zero degree angle (normal incidence to MCP surface) to 0.027 counts per electron at an incident angle of 50° (average in both orientations). At 28 keV, the decrease in detection efficiency as a function of increasing angle was less pronounced, ranging from 0.15 counts per electron at zero degrees to 0.08 counts per electron at 50° (average in both orientations). Experimental data showed lower detection efficiencies compared with previously published data.

  12. 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.

  13. [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.

  14. Edge effects enhance selfing and seed harvesting efforts in the insect-pollinated Neotropical tree Copaifera langsdorffii (Fabaceae)

    PubMed Central

    Tarazi, R; Sebbenn, A M; Kageyama, P Y; Vencovsky, R

    2013-01-01

    Edge effects may affect the mating system of tropical tree species and reduce the genetic diversity and variance effective size of collected seeds at the boundaries of forest fragments because of a reduction in the density of reproductive trees, neighbour size and changes in the behaviour of pollinators. Here, edge effects on the genetic diversity, mating system and pollen pool of the insect-pollinated Neotropical tree Copaifera langsdorffii were investigated using eight microsatellite loci. Open-pollinated seeds were collected from 17 seed trees within continuous savannah woodland (SW) and were compared with seeds from 11 seed trees at the edge of the savannah remnant. Seeds collected from the SW had significantly higher heterozygosity levels (Ho=0.780; He=0.831) than seeds from the edge (Ho=0.702; He=0.800). The multilocus outcrossing rate was significantly higher in the SW (tm=0.859) than in the edge (tm=0.759). Pollen pool differentiation was significant, however, it did not differ between the SW (=0.105) and the edge (=0.135). The variance effective size within the progenies was significantly higher in the SW (Ne=2.65) than at the edge (Ne=2.30). The number of seed trees to retain the reference variance effective size of 500 was 189 at the SW and 217 at the edge. Therefore, it is preferable that seed harvesting for conservation and environmental restoration strategies be conducted in the SW, where genetic diversity and variance effective size within progenies are higher. PMID:23486081

  15. 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

  16. 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.

  17. Genome-wide linkage scan for plasma high density lipoprotein cholesterol, apolipoprotein A-1 and triglyceride variation among American Indian populations: the Strong Heart Family Study

    PubMed Central

    Li, X; Monda, KL.; Göring, HHH; Haack, K; Cole, SA; Diego, VP; Almasy, L; Laston, S; Howard, BV; Shara, NM; Lee, ET; Best, LG; Fabsitz, RR; MacCluer, JW; North, KE

    2011-01-01

    Background Recent studies have identified chromosomal regions linked to variation in high density lipoprotein cholesterol (HDL-C), apolipoprotein A-1 (Apo A-1) and triglyceride (TG), although results have been inconsistent and previous studies of American Indian populations are limited Objective In an attempt to localize quantitative trait loci (QTLs) influencing HDL-C, Apo A-1 and TG, we conducted genome-wide linkage scans of subjects of the Strong Heart Family Study. Methods We implemented analyses in 3484 men and women aged 18 years or older, at three study centers. Results With adjustment for age, sex and center, we detected a QTL influencing both HDL-C (LOD = 4.4, genome-wide P = 0.001) and Apo A-1 (LOD = 3.2, genome-wide P = 0.020) nearest marker D6S289 at 6p23 in the Arizona sample. Another QTL influencing Apo A-1 was found nearest marker D9S287 at 9q22.2 (LOD = 3.0, genome-wide P = 0.033) in the North and South Dakotas. We detected a QTL influencing TG nearest marker D15S153 at 15q22.31 (LOD = 4.5 in the overall sample and LOD = 3.8 in the Dakotas sample, genome-wide P = 0.0044) and when additionally adjusted for waist, current smoking, current alcohol, current estrogen, lipid treatment, impaired fasting glucose, and diabetes, nearest marker D10S217 at 10q26.2 (LOD = 3.7, genome-wide P = 0.0058) in the Arizona population. Conclusions The replication of QTLs in regions of the genome that harbor well-known candidate genes suggest that chromosomes 6p, 9q and 15q warrant further investigation with fine mapping for causative polymorphisms in American Indians. PMID:19429595

  18. 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.

  19. 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.

  20. 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

  1. Liver SULmean at FDG PET/CT: interreader agreement and impact of placement of volume of interest.

    PubMed

    Viner, Maya; Mercier, Gustavo; Hao, Frank; Malladi, Ashish; Subramaniam, Rathan M

    2013-05-01

    To evaluate how interreader agreement and the site of the volume of interest (VOI) affect the agreement and variability of liver mean standardized uptake value normalized to lean body mass (SUL(mean)) at fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT). Institutional review board approval was obtained for this HIPAA-compliant retrospective review of PET/CT images and patient records. PET/CT images were reviewed in 116 randomly selected patients who had undergone a baseline PET/CT examination and who had normal livers according to imaging and biochemical test results. A 30-mm-diameter spherical VOI was placed within the right lobe of the liver above, below, and at the level of the main portal vein. Two readers performed all measurements independently. Analysis of variance, intraclass correlation coefficient (ICC) analysis, and Bland-Altman analysis were performed. The mean SUL(mean) was between 2.11 and 2.17 at the upper, portal, and lower levels of the right lobe of the liver. The coefficient of variance was between 21.0% and 23.1%, without significant differences for location, with the least variance in the upper level. The ICC of the two readers varied between 0.98 and 0.99 (95% confidence interval [CI]: 0.97, 0.99; P = .0001) at each level. The greatest precision (narrowest CI) was also in the upper level. Bias was 0.025 ± 0.10 (standard deviation) at the upper level, was 0.004 ± 0.14 at the lower level, and was 0.047 ± 0.10 at the portal vein (P = .02). For each reader, there was almost perfect reliability between the SUL(mean) measurements made at the three levels, with an ICC of 0.98 (95% CI: 0.98, 0.99; P = .0001). Liver SUL(mean) at FDG PET/CT has excellent interreader agreement, with similar values and variance whether measured at the upper, lower, or portal vein levels within the right lobe of the liver. © RSNA, 2013.

  2. Incidence of neoplasias and effectiveness of postoperative surveillance endoscopy for patients with ulcerative colitis: comparison of ileorectal anastomosis and ileal pouch-anal anastomosis.

    PubMed

    Ishii, Hiroaki; Hata, Keisuke; Kishikawa, Junko; Anzai, Hiroyuki; Otani, Kensuke; Yasuda, Koji; Nishikawa, Takeshi; Tanaka, Toshiaki; Tanaka, Junichiro; Kiyomatsu, Tomomichi; Kawai, Kazushige; Nozawa, Hiroaki; Kazama, Shinsuke; Yamaguchi, Hironori; Ishihara, Soichiro; Sunami, Eiji; Kitayama, Joji; Watanabe, Toshiaki

    2016-03-09

    The incidence of neoplasia after surgery has not been sufficiently evaluated in patients with ulcerative colitis (UC), particularly in the Japanese population, and it is not clear whether surveillance endoscopy is effective in detecting dysplasia/cancer in the remnant rectum or pouch. The aims of this study were to assess and compare postoperative development of dysplasia/cancer in patients with UC who underwent ileorectal anastomosis (IRA) or ileal pouch-anal anastomosis (IPAA) and to evaluate the effectiveness of postoperative surveillance endoscopy. One hundred twenty patients who received postoperative surveillance endoscopy were retrospectively reviewed for development of dysplasia/cancer in the remnant rectal mucosa or pouch. Three hundred seventy-nine endoscopy sessions were conducted for 30 patients after IRA, while 548 pouch endoscopy sessions were conducted for 90 patients after IPAA. In the IRA group, 5 patients developed dysplasia/cancer during postoperative surveillance and in all cases, neoplasia was detected at an early stage. In the IRA group, no patient developed neoplasia within 10 years of diagnosis; the cumulative incidence of neoplasia after disease onset was 7.2, 12.0, and 23.9% at 15, 20, and 25 years, respectively. In one case after stapled IPAA, dysplasia was found at the ileal pouch; a subsequent 9 endoscopy sessions in 8 years did not detect any dysplasia. Neoplasia was found more frequently during postoperative surveillance in the IRA group than in the IPAA group (p = .0028). The cumulative incidence of neoplasia after IRA was 3.8, 8.7, and 21.7% at 10, 15, and 20 years, respectively, and that after IPAA was 1.6% at 20 years. The cumulative incidence of neoplasia after IPAA was minimal. Those who underwent IRA had a greater risk of developing neoplasia than those who underwent IPAA, although postoperative surveillance endoscopy was able to detect dysplasia/cancer at an early stage. IRA can be the surgical procedure of choice only in selected cases in which it would be of benefit to the patient, with more careful surveillance.

  3. Engineered liposomes for potential alpha-particle therapy of metastatic cancer.

    PubMed

    Sofou, Stavroula; Thomas, James L; Lin, Hung-yin; McDevitt, Michael R; Scheinberg, David A; Sgouros, George

    2004-02-01

    Disseminated, metastatic cancer is frequently incurable. Targeted alpha-particle emitters hold great promise as therapeutic agents for disseminated disease. (225)Ac is a radionuclide generator that has a 10-d half-life and results in alpha-emitting daughter elements ((221)Fr, (217)At, (213)Bi) that lead to the emission of a total of 4 alpha-particles. The aim of this study was to develop approaches for stable and controlled targeting of (225)Ac to sites of disseminated tumor metastases. Liposomes with encapsulated (225)Ac were developed to retain the potentially toxic daughters at the tumor site. (225)Ac was passively entrapped in liposomes. To experimentally test the retention of actinium and its daughters by the liposomes, the gamma-emissions of (213)Bi were measured in liposome fractions, which were separated from the parent liposome population and the free radionuclides, at different times. Under equilibrium conditions the decay rate of (213)Bi was used to determine the concentration of (225)Ac. Measurements of the kinetics of (213)Bi activity were performed to estimate the entrapment of (213)Bi, the last alpha-emitting daughter in the decay chain. Stable pegylated phosphatidylcholine-cholesterol liposomes of different sizes and charge were prepared. Multiple (more than 2) (225)Ac atoms were successfully entrapped per liposome. (225)Ac retention by zwitterionic liposomes was more than 88% over 30 d. Retention by cationic liposomes was lower. A theoretical calculation showed that for satisfactory (213)Bi retention (>50%), liposomes of relatively large sizes (>650 nm in diameter) are required. (213)Bi retention was experimentally verified to be liposome-size dependent. For large liposomes, the measured (213)Bi retention was lower than theoretically predicted (less than 10%). This work supports the hypothesis that it may be possible to develop (225)Ac-based therapies by delivering multiple (225)Ac atoms in liposomes. Improvements in the retention of (225)Ac

  4. Substrate impact on the low-temperature growth of GaN thin films by plasma-assisted atomic layer deposition

    SciTech Connect

    Kizir, Seda; Haider, Ali; Biyikli, Necmi

    2016-07-15

    Gallium nitride (GaN) thin films were grown on Si (100), Si (111), and c-plane sapphire substrates at 200 °C via hollow-cathode plasma-assisted atomic layer deposition (HCPA-ALD) using GaEt{sub 3} and N{sub 2}/H{sub 2} plasma as group-III and V precursors, respectively. The main aim of the study was to investigate the impact of substrate on the material properties of low-temperature ALD-grown GaN layers. Structural, chemical, and optical characterizations were carried out in order to evaluate and compare film quality of GaN on different substrates. X-ray reflectivity measurements showed film density values of 5.70, 5.74, and 5.54 g/cm{sup 3} for GaN grown on Si (100), Si (111), and sapphire, respectively. Grazing incidence x-ray diffraction measurements exhibited hexagonal wurtzite structure in all HCPA-ALD grown GaN samples. However, dominant diffraction peak for GaN films grown on Si and sapphire substrates were detected differently as (002) and (103), respectively. X-ray diffraction gonio scans measured from GaN grown on c-plane sapphire primarily showed (002) orientation. All samples exhibited similar refractive index values (∼2.17 at 632 nm) with 2–3 at. % of oxygen impurity existing within the bulk of the films. The grain size was calculated as ∼9–10 nm for GaN grown on Si (100) and Si (111) samples while it was ∼5 nm for GaN/sapphire sample. Root-mean-square surface roughness values found as 0.68, 0.76, and 1.83 nm for GaN deposited on Si (100), Si (111), and sapphire, respectively. Another significant difference observed between the samples was the film growth per cycle: GaN/sapphire sample showed a considerable higher thickness value when compared with GaN/Si samples, which might be attributed to a possibly more-efficient nitridation and faster nucleation of sapphire surface.

  5. 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.

  6. 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

  7. 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.

  8. Alfacalcidol improves muscle power, muscle function and balance in elderly patients with reduced bone mass.

    PubMed

    Schacht, E; Ringe, Johann D

    2012-01-01

    We investigated the effect of daily therapy with 1 mcg alfacalcidol (Doss(®)-TEVA/AWD-pharma) on muscle power, muscle function, balance performance and fear of falls in an open, multi-centered, uncontrolled, prospective study on a cohort of patients with reduced bone mass. Among the 2,097 participants, 87.1% were post-menopausal women and 12.9% were men. Mean age was 74.8 years and mean body mass index (BMI) 26.3 kg/m². A total of 75.3% of the study population had osteoporosis, 81% a diagnosis of "increased risk of falls" and 70.1% had a creatinine clearance (CrCl) of <65 ml/min. Participants underwent muscle function and muscle power tests at onset and after 3 and 6 months: the timed up and go test (TUG) and the chair rising test (CRT). At baseline and after 6 months, participants performed the tandem gait test (TGT) and filled out a questionnaire evaluating fear of falling. Successful performance in the muscle tests is associated with a significantly lower risk of falls and non-vertebral fractures in elderly patients (successful test performance: TUG ≤ 10 s (sec), CRT ≤ 10 s, TGT ≥ 8 steps). A significant improvement in the performance of the two muscle tests was proved already after 3 months of treatment with alfacalcidol and further increased by the end of the therapeutic intervention. There were significant increases in the number of participants able to successfully perform the tests: 24.6% at baseline and 46.3% at the end of trial for the TUG (P < 0.0001) and 21.7% at baseline and 44.2% at the end for the CRT test (P = 0.0001). The mean time used for the TUG was decreased by 3.0 s from the average onset value of 17.0 s and by 3.1 s from the initial average 16.5 s for the CRT. The percentage of participants able to perform the balance test (TGT) increased from 36.0% at onset to 58.6% at the end of the trial (P < 0.0001). An increased fear of falling was reduced by the end of the study in 74.4% of the patients. Throughout the study, there were 26 adverse drug reactions in 11 out of 2,097 patients (incidence 0.52%). No serious adverse drug reactions and no cases of hypercalcemia were documented. We conclude that treatment with alfacalcidol is safe, increases muscle power, muscle function and balance and reduces fear of falls. The significant improvement in the three muscle and balance tests and fear of falls may have a preventative effect on falls and fractures. We suggest that the quantitative risk tests used in this study could be reliable surrogate parameters for the risk of falls and fractures in elderly patients.