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Sample records for heavy element targets

  1. Actinide targets for the synthesis of super-heavy elements

    SciTech Connect

    Roberto, J.; Alexander, Charles W.; Boll, Rose Ann; Ezold, Julie G.; Felker, Leslie Kevin; Rykaczewski, Krzysztof Piotr; Hogle, Susan L.

    2015-06-18

    Since 2000, six new super-heavy elements with atomic numbers 113 through 118 have been synthesized in hot fusion reactions of 48Ca beams on actinide targets. These target materials, including 242Pu, 244Pu, 243Am, 245Cm, 248Cm, 249Cf, and 249Bk, are available in very limited quantities and require specialized production and processing facilities resident in only a few research centers worldwide. This report describes the production and chemical processing of heavy actinide materials for super-heavy element research, current availabilities of these materials, and related target fabrication techniques. The impact of actinide materials in super-heavy element discovery is reviewed, and strategies for enhancing the production of rare actinides including 249Bk, 251Cf, and 254Es are described.

  2. Actinide targets for the synthesis of super-heavy elements

    NASA Astrophysics Data System (ADS)

    Roberto, J. B.; Alexander, C. W.; Boll, R. A.; Burns, J. D.; Ezold, J. G.; Felker, L. K.; Hogle, S. L.; Rykaczewski, K. P.

    2015-12-01

    Since 2000, six new super-heavy elements with atomic numbers 113 through 118 have been synthesized in hot fusion reactions of 48Ca beams on actinide targets. These target materials, including 242Pu, 244Pu, 243Am, 245Cm, 248Cm, 249Cf, and 249Bk, are available in very limited quantities and require specialized production and processing facilities resident in only a few research centers worldwide. This report describes the production and chemical processing of heavy actinide materials for super-heavy element research, current availabilities of these materials, and related target fabrication techniques. The impact of actinide materials in super-heavy element discovery is reviewed, and strategies for enhancing the production of rare actinides including 249Bk, 251Cf, and 254Es are described.

  3. Actinide targets for the synthesis of super-heavy elements

    DOE PAGES

    Roberto, J.; Alexander, Charles W.; Boll, Rose Ann; ...

    2015-06-18

    Since 2000, six new super-heavy elements with atomic numbers 113 through 118 have been synthesized in hot fusion reactions of 48Ca beams on actinide targets. These target materials, including 242Pu, 244Pu, 243Am, 245Cm, 248Cm, 249Cf, and 249Bk, are available in very limited quantities and require specialized production and processing facilities resident in only a few research centers worldwide. This report describes the production and chemical processing of heavy actinide materials for super-heavy element research, current availabilities of these materials, and related target fabrication techniques. The impact of actinide materials in super-heavy element discovery is reviewed, and strategies for enhancing themore » production of rare actinides including 249Bk, 251Cf, and 254Es are described.« less

  4. Preparation of targets by electrodeposition for heavy element studies

    NASA Astrophysics Data System (ADS)

    Eberhardt, K.; Schädel, M.; Schimpf, E.; Thörle, P.; Trautmann, N.

    2004-03-01

    For heavy element studies at GSI, lanthanide and actinide targets have been prepared by molecular plating. The deposition occurs from an isopropanolic solution at 1000-1200 V with current densities of a few mA/cm 2. Several lanthanide targets have been prepared for test experiments. With natGd deposited on a 10 μm thick Be backing foil a target density of 1100 μg/cm 2 could be achieved. Gd-targets were used for the production of α-emitting isotopes of Os, the homologue of hassium (Hs; Z=108), in order to develop a chemical separation procedure for Hs. 248Cm targets with densities up to 730 μg/cm 2 have been produced for recent experiments to investigate the chemical behaviour of Hs. Here, a rotating wheel system with a multi-target device has been applied enabling higher beam intensities, compared to a stationary target. The targets were irradiated with a pulsed 26Mg 5+ beam applying beam currents up to 6.6 μA electr. An α-spectroscopic investigation of the irradiated Cm-targets showed that the Cm-material is not evenly distributed over the entire target area. Very often, for heavy element investigations, chemical separation procedures are required to ensure high purity of the deposited actinide materials.

  5. Commissioning a Rotating Target Wheel Assembly for Heavy Element Studies

    NASA Astrophysics Data System (ADS)

    Fields, L. D.; Bennett, M. E.; Mayorov, D. A.; Folden, C. M.

    2013-10-01

    The heaviest elements are produced artificially by fusing nuclei of light elements within an accelerator to form heavier nuclei. The most direct method to increase the production rate of nuclei is to increase the beam intensity, necessitating the use of a rotating target to minimize damage to the target by deposited heat. Such a target wheel was constructed for heavy element research at Texas A&M University, Cyclotron Institute, consisting of a wheel with three banana-shaped target cutouts. The target is designed to rotate at 1700 rpm, and a fiber optic cable provides a signal to trigger beam pulsing in order to avoid irradiating the spokes between target segments. Following minor mechanical modifications and construction of a dedicated electrical panel, the rotating target assembly was commissioned for a beam experiment. A 15 MeV/u beam of 20Ne was delivered from the K500 cyclotron and detected by a ruggedized silicon detector. The beam pulsing response time was characterized as a function of the rational frequency of the target wheel. Preliminary analysis suggests that the K500 is capable of pulsing at rates of up to 250 Hz, which is sufficient for planned future experiments. Funded by DOE and NSF-REU Program.

  6. Targeting heavy rare earth elements in carbonatite complexes

    NASA Astrophysics Data System (ADS)

    Broom-Fendley, S.; Wall, F.; Gunn, A. G.; Dowman, E.

    2012-04-01

    The world's main sources of the rare earth elements (REE) are concentrated in carbonatite complexes. These have the advantages of high grade and tonnage, combined with low thorium contents, yet they are generally enriched in light rare earths (LREE). The heavy rare earths (HREE, which include Eu-Lu and Y) are more highly sought after because of their role in new and green technologies. HREE are predominantly extracted from ion-adsorption clays in China. These are small, low grade deposits, which are often illegally mined by artisans. Increased government control, environmental legislation and local demand for REE in China have led to high prices and global concerns about the security of supply of the HREE. Alternative sources of the HREE are poorly documented. We present a review of such targets, including: (1) 'abnormal' carbonatites; (2) areas around LREE-rich complexes such as breccia, fenite and latter stage veins; and (3) weathered carbonatites. At Lofdal, Namibia, carbonatite dykes contain xenotime-(Y) together with LREE minerals. The original chemistry of the carbonatite magma, coupled with late-stage magma and fluid evolution, seem to be controlling factors [1, 2]. The Khibina carbonatite, Kola Peninsula, Russia, is an example of where early LREE carbonatites become increasing HREE-enriched as magmas evolve to carbo-hydrothermal fluids [3]. Around carbonatite complexes in Malawi HREE enrichment can be found in breccia and in fenite. Breccia around Songwe shows areas with high Y/La ratios within the matrix caused by narrow zones of xenotime enrichment. Fenite around Kangankunde and Chilwa Island has higher HREE:LREE ratios than the carbonatite [4]. At weathered complexes, such as at Mount Weld in Western Australia, changes in both HREE concentration and LREE:HREE ratios are observed. In currently unworked sections of the deposit, the HREE mineral churchite (YPO4.H2O) has formed concentrations due to groundwater flow [5]. These areas of enrichment are

  7. Uranium fluoride and metallic uranium as target materials for heavy-element experiments at SHIP

    NASA Astrophysics Data System (ADS)

    Kindler, Birgit; Ackermann, Dieter; Hartmann, Willi; Heßberger, Fritz Peter; Hofmann, Sigurd; Hübner, Annett; Lommel, Bettina; Mann, Rido; Steiner, Jutta

    2008-06-01

    In this contribution we describe the production and application of uranium targets for synthesis of heavy elements. The targets are prepared from uranium fluoride (UF 4) and from metallic uranium with thin carbon foils as backing. Targets of UF 4 were produced by thermal evaporation in a similar way as the frequently applied targets out of Bi, Bi 2O 3, Pb, PbS, SmF 3, and NdF 3, prepared mostly from isotopically enriched material [Birgit Kindler, et al., Nucl. Instr. and Meth. A 561 (2006) 107; Bettina Lommel, et al., Nucl. Instr. and Meth. A 561 (2006) 100]. In order to use more intensive beams and to avoid scattering of the reaction products in the target, metallic uranium is favorable. However, evaporation of metallic uranium is not feasible at a sustainable yield. Therefore, we established magnetron sputtering of metallic uranium. We describe production and properties of these targets. First irradiation tests show promising results.

  8. Targets of uranium, plutonium, and curium for heavy-element research

    NASA Astrophysics Data System (ADS)

    Lobanov, Yu. V.; Buklanov, G. V.; Abdullin, F. Sh.; Polyakov, A. N.; Shirokovsky, I. V.; Tsyganov, Yu. S.; Utyonkov, V. K.

    1997-02-01

    The heavy-element research program of the Dubna gas-filled recoil separator requires the use of rather exotic, strongly radioactive targets which can withstand long-term, high-intensity heavy-ion bombardments. A number of targets with thicknesses of 0.1-0.8 mg/cm 2 deposited on various backings by different techniques such as electrospraying, mechanical painting with organic solutions, as well as molecular plating or electrodeposition from organic solutions were tested. The best results were obtained for electroplated targets deposited on 1.5 μm Ti backings. Isotopically enriched targets of 235,236,238U, 242,244Pu, and 248Cm mounted on rotating disks were irradiated by ions ranging from neon to argon with intensities up to 2 × 10 13pps delivered by the U400 cyclotron. During two months of irradiation the total beam dose of the 34S ions applied to the target of 244Pu reached 2.5 × 10 19. Collaborative Dubna-Livermore experiments were performed in 1993-1995 by employing the Dubna gas-filled recoil separator and resulted in the discovery of the new nuclides 262104, 265106, 266106, 267108, and 273110. The experiments aimed at the synthesis of element 114 are under preparation. Target fabrication methods and experimental results for nuclear physics studies at Coulomb energies are described.

  9. Rotating target wheel system for super-heavy element production at ATLAS

    NASA Astrophysics Data System (ADS)

    Greene, John P.; Heinz, Andreas; Falout, Joe; Janssens, Robert V. F.

    2004-03-01

    A new scattering chamber housing a large diameter rotating target wheel has been designed and constructed in front of the Fragment Mass Analyzer (FMA) for the production of very heavy nuclei ( Z>100) using beams from the Argonne Tandem Linear Accelerator System (ATLAS). In addition to the target and drive system, the chamber is extensively instrumented in order to monitor target performance and deterioration. Capabilities also exist to install rotating entrance and exit windows for gas cooling of the target within the scattering chamber. The design and initial tests are described.

  10. Heavy-element nucleosynthesis

    SciTech Connect

    Mathews, G.J.

    1990-10-30

    New measurements and theoretical studies of nuclear properties, together with new astronomical data on the growth of heavy-element abundances during the early history of the Galaxy, now provide a clearer picture of where in nature the elements heavier than iron are produced by rapid (r-process) and show (s-process) neutron capture reactions. The nuclear data suggest that the r-process involves a high-neutron-density beta-flow equilibrium environment and that the s-process may have occurred at a temperature and neutron density consistent with a {sup 13}C({alpha},n){sup 16}0 neutron source. The astronomical data, when compared with simple galactic chemical evolution modes, suggests that the r-process is associated with type II supernovae and that the neutron source must be manufactured by the star. Low-mass type II supernovae are proposed as the most important contributors to the r-process. A {sup 13}C neutron source in intermediate-mass stars is proposed for the s-process. 64 refs., 7 figs.

  11. Transfer reactions with heavy elements

    SciTech Connect

    Hoffman, D.C.

    1986-04-01

    Transfer reactions for several transuranium elements are studied. (/sup 248/Cm, /sup 249/Bk, /sup 249/CF, /sup 254/Es), /sup 16,18/O, /sup 20,22/Ne, and /sup 40,48/Ca projectiles are used. The production of neutron-rich heavy actinides is enhanced by the use of neutron-rich projectiles /sup 18/O and /sup 22/Ne. The maxima of the isotopic distributions occur at only 2 to 3 mass numbers larger for /sup 48/Ca than for /sup 40/Ca reactions with /sup 248/Cm. The cross sections decrease rapidly with the number of nucleons transferred. The use of neutron-rich targets favors the production of neutron-rich isotopes. ''Cold'' heavy targets are produced. Comparisons with simple calculations of the product excitation energies assuming binary transfers indicate that the maxima of the isotopic distributions occur at the lightest product isotope for which the energy exceeds the reaction barrier. The cross sections for transfer of the same nucleon clusters appear to be comparable for a wide variety of systems. 23 refs., 4 figs., 4 tabs.

  12. The Search for Heavy Elements

    ScienceCinema

    None

    2016-07-12

    The 1994 documentary "The Search for Heavy Elements" chronicles the expansion of the periodic table through the creation at Berkeley Lab of elements heavier than uranium. The documentary features a mix of rarely-seen archival footage, historical photos, and interviews with scientists who made history, such as Glenn Seaborg and Albert Ghiorso.

  13. The Search for Heavy Elements

    SciTech Connect

    2008-04-17

    The 1994 documentary "The Search for Heavy Elements" chronicles the expansion of the periodic table through the creation at Berkeley Lab of elements heavier than uranium. The documentary features a mix of rarely-seen archival footage, historical photos, and interviews with scientists who made history, such as Glenn Seaborg and Albert Ghiorso.

  14. Heavy Stars Thrive among Heavy Elements

    NASA Astrophysics Data System (ADS)

    2002-08-01

    VLT Observes Wolf-Rayet Stars in Virgo Cluster Galaxies [1] Summary Do very massive stars form in metal-rich regions of the Universe and in the nuclei of galaxies ? Or does "heavy element poisoning" stop stellar growth at an early stage, before young stars reach the "heavyweight class"? What may at the first glance appear as a question for specialists actually has profound implications for our understanding of the evolution of galaxies, those systems of billions of stars - the main building blocks of the Universe. With an enormous output of electromagnetic radiation and energetic elementary particles, massive stars exert a decisive influence on the surrounding (interstellar) gas and dust clouds . They also eject large amounts of processed elements, thereby participating in the gradual build-up of the many elements we see today. Thus the presence or absence of such stars at the centres of galaxies can significantly change the overall development of those regions and hence, presumably, that of the entire galaxy. A team of European astronomers [2] has now directly observed the presence of so-called Wolf-Rayet stars (born with masses of 60 - 90 times that of the Sun or more) within metal-rich regions in some galaxies in the Virgo cluster, some 50 million light-years away. This is the first unambiguous detection of such massive stellar objects in metal-rich regions . PR Photo 20a/02 : H II regions in the Virgo cluster galaxy NGC 4254 . PR Photo 20b/02 : Multi-object-slit observation of galaxy NGC 4303 . PR Photo 20c/02 : Spectrum of H II region in NGC 4254 with Wolf-Rayet signatures. Production of heavy elements in the Universe Most scientists agree that the Universe in which we live underwent a dramatic event, known as the Big Bang , approximately 15,000 million years ago. During the early moments, elementary particles were formed which after some time united into more complex nuclei and in turn resulted in the production of hydrogen and helium atoms and their isotopes

  15. Octupole correlations in the heavy elements

    SciTech Connect

    Chasman, R.R.

    1986-01-01

    The effects of octupole correlations on the nuclear structure of the heavy elements are discussed. The cluster model description of the heavy elements is analyzed. The relevance of 2/sup 6/-pole deformation and fast El transitions to an octupole model is considered. 30 refs., 21 figs., 1 tab.

  16. 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.

  17. Heavy Metals and Related Trace Elements.

    ERIC Educational Resources Information Center

    Leland, Harry V.; And Others

    1978-01-01

    Presents a literature review of heavy metals and related trace elements in the environment, covering publications of 1976-77. This review includes: (1) trace treatment in natural water and in sediments; and (2) bioaccumulation and toxicity of trace elements. A list of 466 references is presented. (HM)

  18. Heavy Metals and Related Trace Elements.

    ERIC Educational Resources Information Center

    Leland, Harry V.; And Others

    1978-01-01

    Presents a literature review of heavy metals and related trace elements in the environment, covering publications of 1976-77. This review includes: (1) trace treatment in natural water and in sediments; and (2) bioaccumulation and toxicity of trace elements. A list of 466 references is presented. (HM)

  19. The Electronic Structure of Heavy Element Complexes

    SciTech Connect

    Bursten, Bruce E.

    2000-07-25

    The area of study is the bonding in heavy element complexes, and the application of more sophisticated electronic structure theories. Progress is recounted in several areas: (a) technological advances and current methodologies - Relativistic effects are extremely important in gaining an understanding of the electronic structure of compounds of the actinides, transactinides, and other heavy elements. Therefore, a major part of the continual benchmarking was the proper inclusion of the appropriate relativistic effects for the properties under study. (b) specific applications - These include organoactinide sandwich complexes, CO activation by actinide atoms, and theoretical studies of molecules of the transactinide elements. Finally, specific directions in proposed research are described.

  20. Recent research on the heavy transuranium elements

    SciTech Connect

    Seaborg, G.T.

    1988-09-01

    This review is devoted to recent research (performed in the 1980s) on the heavy members of the group, defined as the transcurium elements (with a few references to related work on lighter elements). It covers the discovery of the three heaviest elements, the discovery of new isotopes, investigation of interesting decay properties of some previously known isotopes, investigations of some heavy ion reaction mechanisms in this region, and recent investigations of nuclear and chemical properties. It is not exhaustive in its coverage, is necessarily succinct, and inevitably places emphasis on those aspects with which the author is most familiar. 92 refs., 3 figs.

  1. Heavy Elements and Cool Stars

    NASA Technical Reports Server (NTRS)

    Wahlgren, Glenn M.; Carpenter, Kenneth G.; Norris, Ryan P.

    2008-01-01

    We report on progress in the analysis of high-resolution near-IR spectra of alpha Orionis (M2 Iab) and other cool, luminous stars. Using synthetic spectrum techniques, we search for atomic absorption lines in the stellar spectra and evaluate the available line parameter data for use in our abundance analyses. Our study concentrates on the post iron-group elements copper through zirconium as a means of investigating the slow neutron-capture process of nucleosynthesis in massive stars and the mechanisms that transport recently processed material up into the photospheric region. We discuss problems with the atomic data and model atmospheres that need to be addressed before theoretically derived elemental abundances from pre-supernova nucleosynthesis calculations can be tested by comparison with abundances determined from observations of cool, massive stars.

  2. The CoRoT target HD 49933: a possible seismic signature of heavy elements ionization in the deep convective zone

    NASA Astrophysics Data System (ADS)

    Brito, Ana; Lopes, Ilídio

    2017-04-01

    We use a seismic diagnostic, based on the derivative of the phase shift of the acoustic waves reflected by the surface, to probe the outer layers of the star HD 49933. This diagnostic is particularly sensitive to partial ionization processes occurring above the base of the convective zone. The regions of partial ionization of light elements, hydrogen and helium, have well-known seismological signatures. In this work, we detect a different seismic signature in the acoustic frequencies, which we showed to correspond to the location where the partial ionization of heavy elements occurs. The location of the corresponding acoustic glitch lies between the region of the second ionization of helium and the base of the convective zone, approximately 5 per cent below the surface of the stars.

  3. Production of heavy elements in inhomogeneous cosmologies

    NASA Astrophysics Data System (ADS)

    Rauscher, Thomas; Applegate, James H.; Cowan, John J.; Thielemann, Friedrich-Karl; Wiescher, Michael

    1994-07-01

    Baryon density inhomogeneities during big bang nucleosynthesis can result from a variety of possible causes (e.g., quantum chromodynamic and electroweak phase transitions; cosmic strings). We present here the consequences of such inhomogeneities with special emphasis on the production of heavy elements in a parameter study, varying the global baryon-to-photon ratio eta (which is related to the baryon density and the Hubble constant via eta10 = 64.94 Omegab(H0/50)2 and the length scale of the density inhomogeneities. The production of heavy elements beyond Fe can only occur in neutron-rich environments; thus, we limit our study to neutron-rich zones, originating from neutron diffusion into low-density regions. In this first calculation including elements heavier than Si, we prove an earlier hypothesis that under such conditions r-process elements can be produced, strongly enhanced by the process of fission cycling. Primordial r-process abundances are, however, very sensitive to the choice of eta. Significant amounts, comparable to or larger than the (permitted) floor of heavy-element abundances found in low-metallicity stars at the onset of galactic evolution, can only be obtained for values in excess of eta10 = 133 (i.e., Omegab(h50)2 = 2.0; e.g., Omegab = 1, H0 = 71, or Omegab = 0.5, H0 = 100) and large length scales of inhomogeneities, which minimize the back-diffusion of neutrons into proton-rich regions. Recent investigations analyzing the primordial abundances of light elements seem to set tighter limits, eta10 less than 26 to 39 (Omega b)(h50)2 less than 0.4 to 0.6, from He-4 and apparently considerably lower values based on Li, Be, and B. Under such conditions the predicted abundances of heavy elements are a factor of 105 or more below presently observable limits.

  4. Heavy element abundances and massive star formation

    NASA Technical Reports Server (NTRS)

    Wang, Boqi; Silk, Joseph

    1993-01-01

    The determination of the stellar initial mass function (IMF) remains a great challenge in astronomy. In the solar neighborhood, the IMF is reasonable well determined for stellar masses from about 0.1 to 60 solar mass. However, outside the solar neighborhood, the IMF is poorly known. Among those frequently discussed arguments favoring a different IMF outside the solar neighborhood are the estimated time to consume the remaining gas in spiral galaxies, and the high rate of forming massive stars in starburst galaxies. An interesting question then is whether there may be an independent way of testing possible variations in the IMF. Indeed, the heavy elements in the interstellar medium are mostly synthesized in massive stars, so increasing, or decreasing, the fraction of massive stars naturally leads to a variation in the heavy element yield, and thus, the metallicity. The observed abundance should severely constrain any deviations of the IMF from the locally determined IMF. We focus on element oxygen, which is the most abundant heavy element in the interstellar medium. Oxygen is ejected only by massive stars that can become Type 1 supernovae, and the oxygen abundance is, therefore, a sensitive function of the fraction of massive stars in the IMF. Adopting oxygen enables us to avoid uncertainties in Type 1 supernovae. We use the nucleosynthesis results to calculate the oxygen yield for given IMF. We then calculate the oxygen abundance in the interstellar medium assuming instantaneous recycling of oxygen.

  5. Heavy elements and mixing in red giants

    NASA Astrophysics Data System (ADS)

    Smith, Verne V.

    A brief overview of the s-process in red giants is presented, followed by discussions of three specific topics involving heavy-element s-process nucleosynthesis and mixing in red giants: (1) a comparison of neutron densities derived from observations and from the most recent stellar models, (2) how observations of technetium in S stars have led to a natural division of these stars into two separate groups, one of which is the result of single-star stellar evolution while the other is the result of mass transfer in a binary system, (3) a brief discussion of the recent speculative suggestion that gamma-ray induced photofission of heavy elements (Th and U) might be a source of the Tc observed in certain types of red giants.

  6. Frontiers of heavy element nuclear and radiochemistry

    SciTech Connect

    Hoffman, D.C.

    1997-10-01

    The production and half-lives of the heaviest chemical elements, now known through Z = 112, are reviewed. Recent experimental evidence for the stabilization of heavy element isotopes due to proximity to deformed nuclear shells at Z = 108 and N = 162 is compared with the theoretical predictions. The possible existence of isotopes of elements 107--110 with half-lives of seconds or longer, and production reactions and experimental techniques for increasing the overall yields of such isotopes in order to study both their nuclear and chemical properties are discussed. The present status of studies of the chemical properties of Rf, Ha, and Sg is briefly summarized and prospects for extending chemical studies beyond Sg are considered.

  7. Heavy element affinities in Apollo 17 samples

    NASA Technical Reports Server (NTRS)

    Allen, R. O., Jr.; Jovanovic, S.; Reed, G. W., Jr.

    1975-01-01

    Pb-204, Bi, Tl, and Zn in samples from the Apollo 17 site exhibit relationships not found in samples from other sites. Pb-204, Tl, and Zn in residues remaining after dilute acid leaching are correlated with one another. Orange soil 74220, which is enriched in Pb-204, Tl, and Zn, is included in these relationships. In addition, the submicron metallic phase generally associated with agglutinate formation is correlated with all three of these elements; this relationship has already been reported for Pb-204 in other samples. Thus, orange soil and agglutinates appear to be involved in concentrating heavy volatile metals. A process other than mixing is required to account for this. As a consequence of the isolation of the landing site by the surrounding massifs, local supply and recycling of volatile trace elements in soils may account for some of the interelement relations.

  8. Heavy element affinities in Apollo 17 samples

    NASA Technical Reports Server (NTRS)

    Allen, R. O., Jr.; Jovanovic, S.; Reed, G. W., Jr.

    1975-01-01

    Pb-204, Bi, Tl, and Zn in samples from the Apollo 17 site exhibit relationships not found in samples from other sites. Pb-204, Tl, and Zn in residues remaining after dilute acid leaching are correlated with one another. Orange soil 74220, which is enriched in Pb-204, Tl, and Zn, is included in these relationships. In addition, the submicron metallic phase generally associated with agglutinate formation is correlated with all three of these elements; this relationship has already been reported for Pb-204 in other samples. Thus, orange soil and agglutinates appear to be involved in concentrating heavy volatile metals. A process other than mixing is required to account for this. As a consequence of the isolation of the landing site by the surrounding massifs, local supply and recycling of volatile trace elements in soils may account for some of the interelement relations.

  9. Leap to explore the region of neutron-rich heavy element isotopes

    SciTech Connect

    Hoffman, D.C.

    1985-10-01

    The research aims of the Large Einsteinium Activation Program (LEAP) are described. This program is a major initiative to exploit currently existing expertise in heavy element research and the potential for producing very heavy actinide target materials such as 285-day /sup 254/Es at the High Flux Isotope Reactor at Oak Ridge National Laboratory. The stated aims of the program are to produce heavy element isotopes, to conduct chemical studies of these isotopes, to study the nuclear properties of such isotopes, and to produce a superheavy element (183 neutrons) by the using a /sup 254/Es target and /sup 48/Ca projectiles. 13 refs., 2 figs., 2 tabs. (DWL)

  10. Observation of heavy elements produced during explosive cold fusion

    SciTech Connect

    Matsumoto, T.; Kurokawa, K. )

    1991-11-01

    This paper reports on many-body fusion reactions that may take place during cold fusion. Heavy elements are observed that might have been produced by such reactions during electrolysis of heavy water. Elements such as sodium, magnesium, aluminum, and zinc are observed inside grain-shaped defects in a palladium rod used in a cold fusion experiment.

  11. Nucleosynthesis of heavy elements in the r-process

    SciTech Connect

    Panov, I. V.

    2016-03-15

    The current state of the problem of heavy-element production in the astrophysical r-process is surveyed. The nucleosynthesis process in the neutron-star-merger scenario, within which the problem of free-neutron source is solved, is considered most comprehensively. A model that describes well the observed abundances of heavy elements is examined. Theoretical approaches used in this model to calculate a number of features of short-lived neutron-rich nuclei are described. The contributions of various fission processes to the production of heavy elements are assessed. The possibility of superheavy-element production in the r-process is demonstrated.

  12. Heavy Element Abundances in NGC 5846

    NASA Technical Reports Server (NTRS)

    Jones, Christine

    2000-01-01

    In this paper we analyze the diffuse X-ray coronae surrounding the elliptical galaxy NGC 5846, combining measurements from two observatories, ROSAT and the Advanced Satellite for Cosmology and Astrophysics. We map the gas temperature distribution and find a central cool region within an approximately isothermal gas halo extending to a radius of about 50 kpc and evidence for a temperature decrease at larger radii. With a radially falling temperature profile, the total mass converges to (9.6 +/- 1.0) x 10(exp 12) solar mass at 230 kpc radius. This corresponds to a total mass to blue light ratio of 53 +/- 5 solar mass/solar luminosity. As in other early type galaxies, the gas mass is only a few percent of the total mass. Using the spectroscopic measurements, we also derive radial distributions for the heavy elements silicon and iron and find that the abundances of both decrease with galaxy radius. The mass ratio of Si to Fe lies between the theoretical predictions for element production in SN Ia and SN II, suggesting an important role for SN Ia, as well as SN II, for gas enrichment in ellipticals. Using the 2 SN la yield of Si, we set an upper limit of 0.012 h(sup 2, sub 50) solar neutrino units (SNU) for the SN Ia rate at radii >50 kpc, which is independent of possible uncertainties in the iron L-shell modeling. We compare our observations with the theoretical predictions for the chemical evolution of ellipticals. We conclude that the metal content in stars, if explained by the star formation duration, requires a significant decline in the duration of star formation with galaxy radius, ranging from 1 Gyr at the center to 0.01 Gyr at 100 kpc radius. Alternatively, the decline in metallicity with galaxy radius may be caused by a similar drop with radius in the efficiency of star formation. Based on the Si and Fe measurements presented in this paper, we conclude that the latter scenario is preferred unless a dependence of the SN Ia rate on stellar metallicity is invoked.

  13. Heavy Element Abundances in NGC 5846

    NASA Technical Reports Server (NTRS)

    Jones, Christine

    2000-01-01

    In this paper we analyze the diffuse X-ray coronae surrounding the elliptical galaxy NGC 5846, combining measurements from two observatories, ROSAT and the Advanced Satellite for Cosmology and Astrophysics. We map the gas temperature distribution and find a central cool region within an approximately isothermal gas halo extending to a radius of about 50 kpc and evidence for a temperature decrease at larger radii. With a radially falling temperature profile, the total mass converges to (9.6 +/- 1.0) x 10(exp 12) solar mass at 230 kpc radius. This corresponds to a total mass to blue light ratio of 53 +/- 5 solar mass/solar luminosity. As in other early type galaxies, the gas mass is only a few percent of the total mass. Using the spectroscopic measurements, we also derive radial distributions for the heavy elements silicon and iron and find that the abundances of both decrease with galaxy radius. The mass ratio of Si to Fe lies between the theoretical predictions for element production in SN Ia and SN II, suggesting an important role for SN Ia, as well as SN II, for gas enrichment in ellipticals. Using the 2 SN la yield of Si, we set an upper limit of 0.012 h(sup 2, sub 50) solar neutrino units (SNU) for the SN Ia rate at radii >50 kpc, which is independent of possible uncertainties in the iron L-shell modeling. We compare our observations with the theoretical predictions for the chemical evolution of ellipticals. We conclude that the metal content in stars, if explained by the star formation duration, requires a significant decline in the duration of star formation with galaxy radius, ranging from 1 Gyr at the center to 0.01 Gyr at 100 kpc radius. Alternatively, the decline in metallicity with galaxy radius may be caused by a similar drop with radius in the efficiency of star formation. Based on the Si and Fe measurements presented in this paper, we conclude that the latter scenario is preferred unless a dependence of the SN Ia rate on stellar metallicity is invoked.

  14. Optical model analyses of heavy ion fragmentation in hydrogen targets

    NASA Technical Reports Server (NTRS)

    Townsend, Lawrence W.

    1994-01-01

    Quantum-mechanical optical-model methods for calculating cross sections for the fragmentation of high-energy heavy ions by hydrogen targets are presented. The cross sections are calculated with a knockout-ablation collision formalism which has no arbitrary fitting parameters. Predictions of elemental production cross sections from the fragmentation of 1.2A Ge(V(La-139) nuclei and of isotope production cross sections from the fragmentation of 400A MeV(S-32) nuclei are in good agreement with recently reported experimental measurements.

  15. Target for the heaviest element production at RIKEN

    NASA Astrophysics Data System (ADS)

    Kaji, D.; Morimoto, K.; Yoneda, A.; Hasebe, H.; Yoshida, A.; Haba, H.; Goto, S.; Kudo, H.; Morita, K.

    2008-06-01

    A new gas-cooled rotating target system was developed for the heaviest element production. A target wheel with a diameter of 30.0 cm could be rotated up to 3000 rpm. A helium gas introduced into the target chamber mounted upstream of a gas-filled recoil separator, which enables an effective gas cooling of the target. The development has led to the successful production of heavy nuclides via cold fusion reactions of 208Pb( 64Ni,n) 271Ds, 209Bi( 64Ni,n) 272Rg, 208Pb( 70Zn,n) 277112, and 209Bi( 70Zn,n) 278113.

  16. Abundance of heavy elements in the atmosphere of Aldebaran

    NASA Astrophysics Data System (ADS)

    Gopka, V. F.; Komarov, N. S.

    1990-12-01

    The model-atmospheres method was used to determine the abundance of heavy elements in the atmosphere of Aldebaran. The absorption lines of the heavy elements were identified by calculating the synthetic spectrum and comparing it with the Aldebaran Atlas of Kipper and Klochkova. The main result of the present work is the discovery of a number of absorption lines of r and s processes characteristic for stars of the late spectral type K5 III.

  17. THE HEAVY-ELEMENT MASSES OF EXTRASOLAR GIANT PLANETS, REVEALED

    SciTech Connect

    Miller, Neil; Fortney, Jonathan J.

    2011-08-01

    We investigate a population of transiting planets that receive relatively modest stellar insolation, indicating equilibrium temperatures <1000 K, and for which the heating mechanism that inflates hot Jupiters does not appear to be significantly active. We use structural evolution models to infer the amount of heavy elements within each of these planets. There is a correlation between the stellar metallicity and the mass of heavy elements in its transiting planet(s). It appears that all giant planets possess a minimum of {approx}10-15 Earth masses of heavy elements, with planets around metal-rich stars having larger heavy-element masses. There is also an inverse relationship between the mass of the planet and the metal enrichment (Z{sub pl}/Z{sub star}), which appears to have little dependency on the metallicity of the star. Saturn- and Jupiter-like enrichments above solar composition are a hallmark of all the gas giants in the sample, even planets of several Jupiter masses. These relationships provide an important constraint on planet formation and suggest large amounts of heavy elements within planetary H/He envelopes. We suggest that the observed correlation can soon also be applied to inflated planets, such that the interior heavy-element abundance of these planets could be estimated, yielding better constraints on their interior energy sources. We point to future directions for planetary population synthesis models and suggest future correlations. This appears to be the first evidence that extrasolar giant planets, as a class, are enhanced in heavy elements.

  18. Heavy-element abundance patterns in hot DA white dwarfs

    NASA Astrophysics Data System (ADS)

    Barstow, M. A.; Good, S. A.; Holberg, J. B.; Hubeny, I.; Bannister, N. P.; Bruhweiler, F. C.; Burleigh, M. R.; Napiwotzki, R.

    2003-05-01

    We present a series of systematic abundance measurements for 25 hot DA white dwarfs in the temperature range ~20 000-110 000 K, based on far-ultraviolet spectroscopy with the Space Telescope Imaging Spectrograph (STIS)/Goddard High Resolution Spectrograph (GHRS) on-board Hubble Space Telescope, IUE and FUSE. Using our latest heavy-element blanketed non-local thermodynamic equilibrium (non-LTE) stellar atmosphere calculations we have addressed the heavy-element abundance patterns, making completely objective measurements of abundance values and upper limits using a χ2 fitting technique to determine the uncertainties in the abundance measurements, which can be related to the formal upper limits in those stars where particular elements are not detected. We find that the presence or absence of heavy elements in the hot DA white dwarfs largely reflects what would be expected if radiative levitation is the supporting mechanism, although the measured abundances do not match the predicted values very well, as reported by other authors in the past. Almost all stars hotter than ~50 000 K contain heavy elements. For most of these the spread in element abundances is quite narrow and similar to the abundances measured in G191-B2B. However, there is an unexplained dichotomy at lower temperatures with some stars having apparently pure H envelopes and others having detectable quantities of heavy elements. The heavy elements present in these cooler stars are often stratified, lying in the outermost layers of the envelope. A few strong temperature/evolutionary effects are seen in the abundance measurements. There is a decreasing Si abundance with temperature, the N abundance pattern splits into two groups at lower temperature and there is a sharp decline in Fe and Ni abundance to zero, below ~50 000 K. When detected, the Fe and Ni abundances maintain an approximately constant ratio, close to the cosmic value of ~20. For the hottest white dwarfs observed by STIS, the strongest

  19. Survival and compound nucleus probability of super heavy element Z = 117

    NASA Astrophysics Data System (ADS)

    Manjunatha, H. C.; Sridhar, K. N.

    2017-05-01

    As a part of a systematic study for predicting the most suitable projectile-target combinations for heavy-ion fusion experiments in the synthesis of 289-297Ts, we have calculated the transmission probability ( Tl), compound nucleus formation probabilities ( P_{CN}) and survival probability ( P_{sur}) of possible projectile-target combinations. We have also studied the fusion cross section, survival cross section and fission cross sections for different projectile-target combination of 289-297Ts. These theoretical parameters are required before the synthesis of the super heavy element. The calculated probabilities and cross sections show that the production of isotopes of the super heavy element with Z = 117 is strongly dependent on the reaction systems. The most probable reactions to synthetize the super heavy nuclei 289-297Ts are worked out and listed explicitly. We have also studied the variation of P_{CN} and P_{sur} with the mass number of projectile and target nuclei. This work is useful in the synthesis of the super heavy element Z = 117.

  20. The Chemical Evolution of Heavy Elements in Globular Clusters

    NASA Astrophysics Data System (ADS)

    Shingles, Luke J.; Karakas, Amanda I.; Hirschi, Raphael

    2014-01-01

    We present preliminary results from a chemical evolution model that tracks the composition of heavy elements beyond iron in a globular cluster. The heavy elements can be used as tracers of the nucleosynthetic events that defined the formation and evolution of star clusters in the early Universe. In particular, the chemical evolution model focuses on the hypothesis that rapidly-rotating massive stars produced the heavy elements via the slow neutron-capture process and seeded the proto-cluster while the stars we see today were still forming. We compare our model with heavy element abundances in M4 and M5, and M22. Our results are strongly dependent on the highly uncertain rate of the 17O(α,γ)21Ne reaction, which determines the strength of 16O as a neutron poison. We find that the [Pb/Ba] ratio is too low to match the empirical value, which might suggest that a contribution from AGB stars is required.

  1. The Properties of Heavy Elements in Giant Planet Envelopes

    NASA Astrophysics Data System (ADS)

    Soubiran, François; Militzer, Burkhard

    2016-09-01

    The core-accretion model for giant planet formation suggests a two-layer picture for the initial structure of Jovian planets, with heavy elements in a dense core and a thick H-He envelope. Late planetesimal accretion and core erosion could potentially enrich the H-He envelope in heavy elements, which is supported by the threefold solar metallicity that was measured in Jupiter’s atmosphere by the Galileo entry probe. In order to reproduce the observed gravitational moments of Jupiter and Saturn, models for their interiors include heavy elements, Z, in various proportions. However, their effect on the equation of state of the hydrogen-helium mixtures has not been investigated beyond the ideal mixing approximation. In this article, we report results from ab initio simulations of fully interacting H-He-Z mixtures in order to characterize their equation of state and to analyze possible consequences for the interior structure and evolution of giant planets. Considering C, N, O, Si, Fe, MgO, and SiO2, we show that the behavior of heavy elements in H-He mixtures may still be represented by an ideal mixture if the effective volumes and internal energies are chosen appropriately. In the case of oxygen, we also compute the effect on the entropy. We find the resulting changes in the temperature-pressure profile to be small. A homogeneous distribution of 2% oxygen by mass changes the temperature in Jupiter’s interior by only 80 K.

  2. Separation of transuranium elements from irradiated targets

    SciTech Connect

    Wham, R.M.; Benker, D.E.; Felker, L.K.; Chattin, F.R.

    1993-12-31

    Aluminum targets containing curium/americium oxide are irradiated to produce the transcurium actinides einsteinium, fermium, berkelium, and californium. Recovery of recycle curium/americium and the transcurium elements involves several chemical processing steps to selectively recover those elements and remove fission products. Chemical processing steps developed at the Radiochemical Engineering Development Center (REDC) include aluminum dejacketing, solvent extraction to remove bulk impurities, solvent extraction to remove plutonium, anion exchange to partition curium and transcurium elements from the rare earths, and a second anion exchange cycle to separate americium/curium from the transcurium elements.

  3. Characterization of aerosol transport in a recoil transfer chamber for heavy element chemistry

    NASA Astrophysics Data System (ADS)

    Lopez Morales, Gabriel; Tereshatov, Evgeny; Folden, Charles

    2014-09-01

    Heavy elements (HE) are elements with Z >103 that can be synthesized via target material bombardment by accelerated charged particles. Production and investigation of properties of new elements result in understanding of upper limit of Periodic Table of Elements. Study of chemical behavior of HE is usually based on comparison with their light homologue properties. Such experiments require transportation of elements of interest from a target chamber to a radiochemical laboratory within several seconds. Aerosol transport is a widely known way to transfer non-volatile elements in on-line experiments. This particular project is devoted to design, characterization and optimization of aerosol transport for implementation in future experiments at Cyclotron Institute, Texas A&M University. Different types of aerosol generators and particle parameters such as: size distribution, concentration and charge have been considered. Results showing procedure development will be presented. *Funded by DOE and NSF-REU Program.

  4. New Detector System for Super Heavy Elements Detection

    NASA Astrophysics Data System (ADS)

    Wieloch, A.; Sosin, Z.; Bańka, P.; Gonciarz, A.; Péter, J.; Drouart, A.; Dayras, R.; Łojek, K.; Stodel, Ch.; Adamczyk, M.; Avez, B.; Lasko, P.; Zosiak, Ł.; Kozik, T.; Alamanos, N.; Gillibert, A.; Grévy, S.; Hanappe, F.; Hannachi, F.; Hue, R.; Khouaja, A.; Lopez-Martens, A.; Manduci, L.; de Oliveira Santos, F.; Politi, G.; Saint-Laurent, M. G.; Stuttgé, L.; Vandamme, Ch.; Wieleczko, J. P.; Piasecki, E.; Trzcińska, A.; Gawlikowicz, W.; Kisielewski, M.; Kowalczyk, M.; Kordyasz, A.; Błocki, J.

    A new detector system dedicated for very/super heavy elements (VHE/SHE) detection that decay by spontaneous fission is presented. Such a decay mode of nuclei can be found e.g. in the region of Z≈100 (Fermium). Future experiments realized in the frame of French-Polish collaboration at the cyclotrons in GANIL and in the Heavy Ion Laboratory (HIL), University of Warsaw, is described. The results of test measurements made in the HIL for reactions 20Ne(8 A.MeV)+120Sn, 179Au are presented.

  5. Formation of super-heavy elements in astrophysical nucleosynthesis

    SciTech Connect

    Zagrebaev, V. I.; Karpov, A. V.; Mishustin, I. N.; Greiner, Walter

    2012-10-20

    The unexplored area of heavy neutron-rich nuclides is extremely important for the understanding of the r process of astrophysical nucleogenesis. For elements with Z>100 only neutron deficient isotopes (located to the left of the stability line) have been synthesized so far. The 'north-east' area of the nuclear map can be reached neither in fusion reactions nor in fragmentation processes. Low energy multi-nucleon transfer reactions are quite promising for the production and study of neutron-rich heavy nuclei including those located at the superheavy (SH) island of stability [1]. The neutron capture process is considered here as an alternative method for the production of SH nuclei. Requirements for the pulsed reactors of the next generation that could be used for the synthesis of long-living neutron rich SH nuclei are formulated. Formation of SH nuclei in supernova explosions is also discussed and the abundance of SH elements in nature is estimated.

  6. Effects of rare earth elements on the distribution of mineral elements and heavy metals in horseradish.

    PubMed

    Wang, Lihong; Huang, Xiaohua; Zhou, Qing

    2008-09-01

    In order to investigate the effects of rare earth elements (REEs) on horseradish, the distribution of the mineral elements and heavy metals in different organs of horseradish have been studied by using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Meanwhile, three variable major parameters, namely the concentration of REEs, the type of REEs, and the growth stage of plant were chosen. The results indicated that the test REEs, Ce(III) and Tb(III), could be accumulated in leaves, stems and roots of horseradish. In addition, we found that the content of mineral elements was increased in horseradish treated with 20mgl(-1) of Ce(III), but not those with the 20mgl(-1) of Tb(III). Moreover, the content of mineral elements in horseradish was decreased with the increasing concentration of REEs (100, 300mgl(-1)). Furthermore, we found that there were the opposite effects on the content of the heavy metals in horseradish treated with REEs. Finally, we found that the effect of REEs on the accumulation of REEs, and the content of mineral elements or heavy metals of horseradish during vigorous growth stage, no matter positive or negative, was more obvious than that of the other growth stages. These results demonstrated that the distribution behaviors of mineral elements and heavy metals in horseradish can be affected by the type and concentration of REEs, and the growth period of plant.

  7. The interstellar abundances of tin and four other heavy elements

    NASA Technical Reports Server (NTRS)

    Hobbs, L. M.; Welty, D. E.; Morton, D. C.; Spitzer, L.; York, D. G.

    1993-01-01

    Spectra recorded at 1150-1600 A with an instrumental resolution near 16 km/s were obtained with the Goddard High-Resolution Spectrograph on board the HST. The gaseous interstellar abundances of five heavy elements along the light paths to 23 Ori, 15 Mon, 1 Sco, Pi Sco, and Pi Aqr were determined from the observations. The 1400.450 A line of Sn II was detected and identified toward three stars; at Z = 50, tin is the first element from the fifth row of the periodic table to be identified in the interstellar medium. One spectral line of each of Cu II (Z = 29) and Ga II (Z = 31), three lines of Ge II (Z = 32), and two lines of Kr I (Z = 36) were also detected toward some or all of the five stars. The depletions of these five heavy elements generally decrease monotonically with increasing atomic number toward each of the six stars, and tin is generally undepleted within the observational errors. The depletions of 26 elements from the interstellar gas in an average dense interstellar cloud appear to correlate with the elemental 'nebular' condensation temperatures more closely than with the first ionization potentials.

  8. The interstellar abundances of tin and four other heavy elements

    NASA Technical Reports Server (NTRS)

    Hobbs, L. M.; Welty, D. E.; Morton, D. C.; Spitzer, L.; York, D. G.

    1993-01-01

    Spectra recorded at 1150-1600 A with an instrumental resolution near 16 km/s were obtained with the Goddard High-Resolution Spectrograph on board the HST. The gaseous interstellar abundances of five heavy elements along the light paths to 23 Ori, 15 Mon, 1 Sco, Pi Sco, and Pi Aqr were determined from the observations. The 1400.450 A line of Sn II was detected and identified toward three stars; at Z = 50, tin is the first element from the fifth row of the periodic table to be identified in the interstellar medium. One spectral line of each of Cu II (Z = 29) and Ga II (Z = 31), three lines of Ge II (Z = 32), and two lines of Kr I (Z = 36) were also detected toward some or all of the five stars. The depletions of these five heavy elements generally decrease monotonically with increasing atomic number toward each of the six stars, and tin is generally undepleted within the observational errors. The depletions of 26 elements from the interstellar gas in an average dense interstellar cloud appear to correlate with the elemental 'nebular' condensation temperatures more closely than with the first ionization potentials.

  9. Heavy ion beam transport and interaction with ICF targets

    NASA Astrophysics Data System (ADS)

    Velarde, G.; Aragonés, J. M.; Gago, J. A.; Gámez, L.; González, M. C.; Honrubia, J. J.; Martínez-Val, J. M.; Mínguez, E.; Ocaña, J. L.; Otero, R.; Perlado, J. M.; Santolaya, J. M.; Serrano, J. F.; Velarde, P. M.

    1986-01-01

    Numerical simulation codes provide an essential tool for analyzing the very broad range of concepts and variables considered in ICF targets. In this paper, the relevant processes embodied in the NORCLA code, needed to simulate ICF targets driven by heavy ion beams will be presented. Atomic physic models developed at DENIM to improve the atomic data needed for ion beam plasma interaction will be explained. Concerning the stopping power, the average ionization potential following a Thomas-Fermi model has been calculated, and results are compared with full quantum calculations. Finally, a parametric study of multilayered single shell targets driven by heavy ion beams will be shown.

  10. Lanthanide contraction and magnetism in the heavy rare earth elements.

    PubMed

    Hughes, I D; Däne, M; Ernst, A; Hergert, W; Lüders, M; Poulter, J; Staunton, J B; Svane, A; Szotek, Z; Temmerman, W M

    2007-04-05

    The heavy rare earth elements crystallize into hexagonally close packed (h.c.p.) structures and share a common outer electronic configuration, differing only in the number of 4f electrons they have. These chemically inert 4f electrons set up localized magnetic moments, which are coupled via an indirect exchange interaction involving the conduction electrons. This leads to the formation of a wide variety of magnetic structures, the periodicities of which are often incommensurate with the underlying crystal lattice. Such incommensurate ordering is associated with a 'webbed' topology of the momentum space surface separating the occupied and unoccupied electron states (the Fermi surface). The shape of this surface-and hence the magnetic structure-for the heavy rare earth elements is known to depend on the ratio of the interplanar spacing c and the interatomic, intraplanar spacing a of the h.c.p. lattice. A theoretical understanding of this problem is, however, far from complete. Here, using gadolinium as a prototype for all the heavy rare earth elements, we generate a unified magnetic phase diagram, which unequivocally links the magnetic structures of the heavy rare earths to their lattice parameters. In addition to verifying the importance of the c/a ratio, we find that the atomic unit cell volume plays a separate, distinct role in determining the magnetic properties: we show that the trend from ferromagnetism to incommensurate ordering as atomic number increases is connected to the concomitant decrease in unit cell volume. This volume decrease occurs because of the so-called lanthanide contraction, where the addition of electrons to the poorly shielding 4f orbitals leads to an increase in effective nuclear charge and, correspondingly, a decrease in ionic radii.

  11. Heavy Ion Inertial Fusion Energy: Summaries of Program Elements

    SciTech Connect

    Friedman, A; Barnard, J J; Kaganovich, I; Seidl, P A; Briggs, R J; Faltens, A; Kwan, J W; Lee, E P; Logan, B G

    2011-02-28

    The goal of the Heavy Ion Fusion (HIF) Program is to apply high-current accelerator technology to IFE power production. Ion beams of mass {approx}100 amu and kinetic energy {>=} 1 GeV provide efficient energy coupling into matter, and HIF enjoys R&D-supported favorable attributes of: (1) the driver, projected to be robust and efficient; see 'Heavy Ion Accelerator Drivers.'; (2) the targets, which span a continuum from full direct to full indirect drive (and perhaps fast ignition), and have metal exteriors that enable injection at {approx}10 Hz; see 'IFE Target Designs'; (3) the near-classical ion energy deposition in the targets; see 'Beam-Plasma Interactions'; (4) the magnetic final lens, robust against damage; see 'Final Optics-Heavy Ion Beams'; and (5) the fusion chamber, which may use neutronically-thick liquids; see 'Liquid-Wall Chambers.' Most studies of HIF power plants have assumed indirect drive and thick liquid wall protection, but other options are possible.

  12. Heavy-Element Abundances in Solar Energetic Particle Events

    NASA Technical Reports Server (NTRS)

    Reames, D. V.; Ng, C. K.

    2004-01-01

    We survey the relative abundances of elements with 1 < or equal to Z < or equal to 82 in solar energetic particle (SEP) events observed at 2-10 MeV/amu during nearly 9 years aboard the Wind spacecraft, with special emphasis on enhanced abundances of elements with Z > or equal to 34. Abundances of Fe/O again show a bimodal distribution with distinct contributions from impulsive and gradual SEP events as seen in earlier solar cycles. Periods with greatly enhanced abundances of (50 < or equal to Z < or equal to 56)/O, like those with enhanced (3)He/(4)He, fall prominently in the Fe-rich population of the impulsive SEP events. In a sample of the 39 largest impulsive events, 25 have measurable enhancements in (50 < or equal to z < or equal to 56)/O and (76 < or equal to Z < or equal to 82)/O, relative to coronal values, ranging from approx. 100 to 10,000. By contrast, in a sample of 45 large gradual events the corresponding enhancements vary from approx. 0.2 to 20. However, the magnitude of the heavy-element enhancements in impulsive events is less striking than their strong correlation with the Fe spectral index and flare size, with the largest enhancements occurring in flares with the steepest Fe spectra, the smallest Fe fluence, and the lowest X-ray intensity, as reported here for the first time. Thus it seems that small events with low energy input can produce only steep spectra of the dominant species but accelerate rare heavy elements with great efficiency, probably by selective absorption of resonant waves in the flare plasma. With increased energy input, enhancements diminish, as heavy ions are depleted, and spectra of the dominant species harden.

  13. Quasifission in heavy and superheavy element formation reactions

    NASA Astrophysics Data System (ADS)

    Hinde, D. J.; Dasgupta, M.; Jeung, D. Y.; Mohanto, G.; Prasad, E.; Simenel, C.; Walshe, J.; Wahkle, A.; Williams, E.; Carter, I. P.; Cook, K. J.; Kalkal, Sunil; Rafferty, D. C.; Rietz, R. du; Simpson, E. C.; David, H. M.; Düllmann, Ch. E.; Khuyagbaatar, J.

    2016-12-01

    Superheavy elements are created in the laboratory by the fusion of two heavy nuclei. The large Coulomb repulsion that makes superheavy elements decay also makes the fusion process that forms them very unlikely. Instead, after sticking together for a short time, the two nuclei usually come apart, in a process called quasifission. Mass-angle distributions give the most direct information on the characteristics and time scales of quasifission. A systematic study of carefully chosen mass-angle distributions has provided information on the global trends of quasifission. Large deviations from these systematics reveal the major role played by the nuclear structure of the two colliding nuclei in determining the reaction outcome, and thus implicitly in hindering or favouring superheavy element production.

  14. The application of alpha spectrometry to the discovery of new elements heavy-ion beam bombardment

    NASA Astrophysics Data System (ADS)

    Nitschke, J. M.

    1984-06-01

    Starting with polonium in 1898, alpha spectrometry has played a decisive role in the discovery of new, heavy elements. For even-even nuclei, alpha spectra have proven simple to interpret and exhibit systematic trends that allow extrapolation to unknown isotopes. The early discovery of the "natural" alpha decay series led to the very powerful method of "genetically" linking the decay of new elements to the well-established alpha emission of "daughter" and "granddaughter" nuclei. This technique has been used for all recent discoveries of new elements, including Z = 101, thin samples suitable for alpha spectrometry were prepared by chemical methods. With the advent of heavy-ion accelerators, new sample preparation methods emerged. These were based on the large momentum transfer associated with heavy-ion reactions, which produced energetic target recoils that, when ejected from the target, could be thermalized in helium gas. Subsequent electrical deposition or a helium jet technique yielded samples that were not only thin enough for alpha spectrometry, but also for alpha and beta-recoil experiments. Many variations of these methods have been developed and will be covered in this paper. For the synthesis of element 106, an aerosol-based recoil transport technique was devised. In this most recent experiments, alpha spectrometry has been coupled with the magnetic analysis of the recoils. The time from production to analysis of an isotope has thereby been reduced to 10 -1-10 0s for helium jets and 10 1-10 3 s for rapid chemical separations. Experiments are now in progress to synthesize super heavy elements (SHE) and to analyse them with These latest techniques. Again, alpha spectrometry will play a major role, since the expected signature for the decay of a SHE is a sequence of alpha decays followed by spontaneous fission.

  15. LDRD Final Report: Surrogate Nuclear Reactions and the Origin of the Heavy Elements (04-ERD-057)

    SciTech Connect

    Escher, J E; Bernstein, L A; Bleuel, D; Burke, J; Church, J A; Dietrich, F S; Forssen, C; Gueorguiev, V; Hoffman, R D

    2007-02-23

    Research carried out in the framework of the LDRD project ''Surrogate Nuclear Reactions and the Origin of the Heavy Elements'' (04-ERD-057) is summarized. The project was designed to address the challenge of determining cross sections for nuclear reactions involving unstable targets, with a particular emphasis on reactions that play a key role in the production of the elements between Iron and Uranium. This report reviews the motivation for the research, introduces the approach employed to address the problem, and summarizes the resulting scientific insights, technical findings, and related accomplishments.

  16. The importance of closed shell structures in the synthesis of super heavy elements

    NASA Astrophysics Data System (ADS)

    Hamilton, J. H.; Hofmann, S.; Oganessian, Y. T.

    2015-02-01

    The importance of shell closures and gaps in the single-particle energies for protons and neutrons on the stability of elements beyond Z = 100 will be described. Following the development of microscopic models with shell corrections, microscopic-macroscopic models predicted large gaps in the single-particle energy levels for protons and neutrons at Z = 102, 108 and N = 152, 162 for the same deformed shapes. Shell gaps for spherical shapes for N = 184 and Z = 114, 120 or 126 were also predicted to form an "Island of Stability" with very long half lives for fission and alpha decay. Cold fusion reactions involving beams of Ca to Zn and targets of stable 208Pb and 209Bi were pioneered at GSI and used to synthesize new elements for Z = 107 to 112 and in Japan a new isotope of 113. Hot fusion reactions between radioactive actinide targets and neutron-rich 48Ca beams were pioneered in JINR leading to the synthesis of new elements with Z = 113 to 118. Data on two neutron separation energies, spontaneous fission half lives and total half lives of super heavy elements showing the importance of reinforcement of the Z = 102, N = 152 and Z = 108, N = 162 single particle level gaps at the same deformation and Z = 114-126, N = 184 shell gaps in the synthesis of super heavy elements 107 to 118 are presented along with the latest results on their synthesis.

  17. The Origin and Distribution of Heavy Elements in HCG 62

    NASA Technical Reports Server (NTRS)

    Vrtilek, Jan; Lavoie, Anthony R. (Technical Monitor)

    2000-01-01

    We present recent data on the compact group HCG 62 taken with AXAF CCD Imaging Spectrometer-S (ACIS-S) on Chandra. The sparseness of groups and their relatively simple dynamical history allow the properties of the Intergalatic Medium (IGM) to be more directly related to galaxy evolution than may be possible in clusters, and their lower gas temperatures produce strong lines from a broader range of elements than is the case in hotter clusters. This observation exploits the high X-ray brightness of HCG 62 to determine accurately the abundances of heavy elements as a function of position in the group, to test whether abundance variations are associated with individual galaxies, and to trace the origin of the enrichment.

  18. Recent heavy flavor physics results from fixed target experiments

    SciTech Connect

    Spiegel, L.

    1991-11-01

    Recent results from fixed target experiments in the field of heavy quark flavors, as published or otherwise disseminated in the last year, are reviewed. Emphasis is placed on distilling the main conclusions from these results. 35 refs., 5 figs., 4 tabs.

  19. Isotopic and Elemental Compositions of Ar, Kr, and Xe in Bulk, Slow, and Fast Solar Wind Targets from Genesis

    NASA Astrophysics Data System (ADS)

    Vogel, N.; Baur, H.; Burnett, D. S.; Heber, V. S.; Wieler, R.

    2010-03-01

    We present new heavy noble gas isotopic and elemental data from GENESIS targets exposed to the bulk, the fast, and the slow solar wind. Implications on fractionation effects between the Sun and the Solar Wind will be discussed.

  20. In-beam fission study for Heavy Element Synthesis

    NASA Astrophysics Data System (ADS)

    Nishio, Katsuhisa

    2013-12-01

    Fission fragment mass distributions were measured in heavy-ion induced fissions using 238U target nucleus. The measured mass distributions changed drastically with incident energy. The results are explained by a change of the ratio between fusion and qasifission with nuclear orientation. A calculation based on a fluctuation dissipation model reproduced the mass distributions and their incident energy dependence. Fusion probability was determined in the analysis. Evaporation residue cross sections were calculated with a statistical model in the reactions of 30Si + 238U and 34S + 238U using the obtained fusion probability in the entrance channel. The results agree with the measured cross sections for seaborgium and hassium isotopes.

  1. Colliding Neutron Stars as the Source of Heavy Elements

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-09-01

    Where do the heavy elements the chemical elements beyond iron in our universe come from? One of the primary candidate sources is the merger of two neutron stars, but recent observations have cast doubt on this model. Can neutron-star mergers really be responsible?Elements from Collisions?Periodic table showing the origin of each chemical element. Those produced by the r-process are shaded orange and attributed to supernovae in this image; though supernovae are one proposed source of r-process elements, an alternative source is the merger of two neutron stars. [Cmglee]When a binary-neutron-star system inspirals and the two neutron stars smash into each other, a shower of neutrons are released. These neutrons are thought to bombard the surrounding atoms, rapidly producing heavy elements in what is known as r-process nucleosynthesis.So could these mergers be responsible for producing the majority of the universes heavy r-process elements? Proponents of this model argue that its supported by observations. The overall amount of heavy r-process material in the Milky Way, for instance, is consistent with the expected ejection amounts from mergers, based both on predicted merger rates for neutron stars in the galaxy, and on the observed rates of soft gamma-ray bursts (which are thought to accompany double-neutron-star mergers).Challenges from Ultra-Faint DwarfsRecently, however, r-process elements have been observed in ultra-faint dwarf satellite galaxies. This discovery raises two major challenges to the merger model for heavy-element production:When neutron stars are born during a core-collapse supernova, mass is ejected, providing the stars with asymmetric natal kicks. During the second collapse in a double-neutron-star binary, wouldnt the kick exceed the low escape velocity of an ultra-faint dwarf, ejecting the binary before it could merge and enrich the galaxy?Ultra-faint dwarfs have very old stellar populations and the observation of r-process elements in these stars

  2. Abundances in three heavy-element stars in Omega Centarui

    NASA Astrophysics Data System (ADS)

    Vanture, Andrew D.; Wallerstein, George; Brown, Jeffery A.

    1994-08-01

    The abundances of the iron-peak elements Fe, Ni, and Ti, the light metals Mg, Al, and K, and the s-process elements Rb, Y, and Zr are determined for the heavy-element stars ROA 371, ROA 5293, and ROA 3812 in the globular cluster Omega Centauri. ROA 3812 and ROA 5293 are classified as S stars while ROA 371 is classified as a K5 barium star. The metallicities of ROA 3812, 5293, and 371 are (Fe/H) = -0.7, -0.8, and -1.0 respectively. Thus, ROA 371 has a metallicity slightly higher than the red giants analyzed by Brown et al. (1991) and ROA 3812 and 5293 have metallicities near the upper end of the range for the cluster. All three stars show an excess of Al, which is common in red giants of Omega Centauri, and a mean excess of the s-process elements Rb, Y, and Zr of 1.4 dex. In addition, all three stars are too faint to be asymptotic giant branch (AGB) stars according to current theory. Hence, they were either formed with their present composition, as suggested by Lloyd Evans (1983a) or are binaries that have had their atmospheres polluted by a now defunct companion. Based upon the dependence of (s/Fe) on (Fe/H) for various s-process elements over a range from (Fe/H) = -2.0 to (Fe/H) = -0.7, we show that the Lloyd Evans hypothesis is probably correct. This shows that mass loss from AGB stars was contributing s-proces elements to the intracluster gas for as much as 109 yr before Type Ia SNe swept the cluster clear of gas and terminated star formation.

  3. Molecular dynamics simulations of ion range profiles for heavy ions in light targets

    SciTech Connect

    Lan, Chune; Xue, Jianming; Zhang, Yanwen; Morris, James R.; Zhu, Zihua; Gao, Yuan; Wang, Yugang; Yan, Sha; Weber, William J.

    2012-09-01

    The determination of stopping powers for slow heavy ions in targets containing light elements is important to accurately describe ion-solid interactions, evaluate ion irradiation effects and predict ion ranges for device fabrication and nuclear applications. Recently, discrepancies of up to 40% between the experimental results and SRIM (Stopping and Range of Ions in Matter) predictions of ion ranges for heavy ions with medium and low energies (<25 keV/nucleon) in light elemental targets have been reported. The longer experimental ion ranges indicate that the stopping powers used in the SRIM code are overestimated. Here, a molecular dynamics simulation scheme is developed to calculate the ion ranges of heavy ions in light elemental targets. Electronic stopping powers generated from both a reciprocity approach and the SRIM code are used to investigate the influence of electronic stopping on ion range profiles. The ion range profiles for Au and Pb ions in SiC and Er ions in Si, with energies between 20 and 5250 keV, are simulated. The simulation results show that the depth profiles of implanted ions are deeper and in better agreement with the experiments when using the electronic stopping power values derived from the reciprocity approach. These results indicate that the origin of the discrepancy in ion ranges between experimental results and SRIM predictions in the low energy region may be an overestimation of the electronic stopping powers used in SRIM.

  4. Molecular dynamics simulations of ion range profiles for heavy ions in light targets

    SciTech Connect

    Lan, Chune; Xue, Jianming; Zhang, Yanwen; Morris, James R; Zhu, Zihua; Gao, Yuan; Wang, Yugang; Yan, Sha; Weber, William J

    2012-01-01

    The determination of stopping powers for slow heavy ions in targets containing light elements is important to accurately describe ion-solid interactions, evaluate ion irradiation effects and predict ion ranges for device fabrication and nuclear applications. Recently, discrepancies of up to 40% between the experimental results and SRIM (Stopping and Range of Ions in Matter) predictions of ion ranges for heavy ions with medium and low energies (< {approx} 25 keV/nucleon) in light elemental targets have been reported. The longer experimental ion ranges indicate that the stopping powers used in the SRIM code are overestimated. Here, a molecular dynamics simulation scheme is developed to calculate the ion ranges of heavy ions in light elemental targets. Electronic stopping powers generated from both a reciprocity approach and the SRIM code are used to investigate the influence of electronic stopping on ion range profiles. The ion range profiles for Au and Pb ions in SiC and Er ions in Si, with energies between 20 and 5250 keV, are simulated. The simulation results show that the depth profiles of implanted ions are deeper and in better agreement with the experiments when using the electronic stopping power values derived from the reciprocity approach. These results indicate that the origin of the discrepancy in ion ranges between experimental results and SRIM predictions in the low energy region may be an overestimation of the electronic stopping powers used in SRIM.

  5. The heavy element yields of neutron capture nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Cameron, A. G. W.

    1982-01-01

    Consideration of the contribution made to the abundances of the heavy element isotopes by the S- and R-processes of nucleosynthesis has led to the determination that the previous assumption concerning the exclusive alignment of isobars to one or the other of these processes is probably in error. If the relatively small odd and even mass number abundance fluctuations characterizing R-process abundances are always the case, as assumed by this study, S-process contributions to the abundances of R-process isobars are substantial, consistent with transient flashing episodes in the S-process neutron production processes. A smooth and monotonically-decreasing curve of the abundance of the S-process yields times the neutron capture cross-section versus mass number is therefore the primary tool for the separation of the abundances due to the two processes.

  6. Uniform fuel target implosion in heavy ion inertial fusion

    NASA Astrophysics Data System (ADS)

    Kawata, S.; Karino, T.; Kondo, S.; Iinuma, T.; Barada, D.; Ma, Y. Y.; Ogoyski, A. I.

    2016-05-01

    For a steady operation of a fusion power plant the target implosion should be robust against the implosion non-uniformities. In this paper the non-uniformity mitigation mechanisms in the heavy ion beam (HIB) illumination are discussed in heavy ion inertial fusion (HIF). A density valley appears in the energy absorber, and the large-scale density valley also works as a radiation energy confinement layer, which contributes to the radiation energy smoothing for the HIB illumination non-uniformity. The large density-gradient scale, which is typically ∼500μm in HIF targets, also contributes to a reduction of the Rayleigh- Taylor instability growth rate. In HIF a wobbling HIBs illumination would also reduce the Rayleigh-Taylor instability growth and to realize a uniform implosion.

  7. Recent Super Heavy Element Experiments at GSI-SHIP

    NASA Astrophysics Data System (ADS)

    Stoyer, M.; Hofmann, S.; Heinz, S.; Mann, R.; Maurer, J.; Khuyagbaatar, J.; Ackermann, D.; Antalic, S.; Barth, W.; Burkhard, H. G.; Comas, V. F.; Dahl, L.; Eberhardt, K.; Henderson, R.; Heredia, J. A.; Hessberger, F. P.; Kenneally, J.; Kindler, B.; Kojouharov, I.; Kratz, J. V.; Lang, R.; Leino, M.; Lommel, B.; Moody, K.; Munzenberg, G.

    2014-09-01

    The synthesis of element 116 (Lv) in fusion-evaporation reactions of a 48Ca beam with 248Cm targets was studied at the velocity filter SHIP of GSI in Darmstadt. At excitation energies of the compound nuclei of 40.9 MeV, four decay chains were measured, which were assigned to the isotope 292Lv, and one chain, which was assigned to 293Lv. Measured cross-sections of (3.4 + 2.7 -1.6) pb and (0.9 + 2.1 -0.7) pb, respectively, and decay data of the chains agree with data measured previously at the Flerov Laboratory of Nuclear Reactions in Dubna. We measured the velocity spectra of the 116 isotopes and transfer products which reveal the reaction type underlying the synthesis of the nuclei. The experience gained in this experiment will serve as a basis for future experiments to study still heavier elements at the velocity filter SHIP. Searches for element 120 in fusion-evaporation reactions of a 54Cr beam with 248Cm targets were studied later at SHIP and progress in the analysis will be discussed. The synthesis of element 116 (Lv) in fusion-evaporation reactions of a 48Ca beam with 248Cm targets was studied at the velocity filter SHIP of GSI in Darmstadt. At excitation energies of the compound nuclei of 40.9 MeV, four decay chains were measured, which were assigned to the isotope 292Lv, and one chain, which was assigned to 293Lv. Measured cross-sections of (3.4 + 2.7 -1.6) pb and (0.9 + 2.1 -0.7) pb, respectively, and decay data of the chains agree with data measured previously at the Flerov Laboratory of Nuclear Reactions in Dubna. We measured the velocity spectra of the 116 isotopes and transfer products which reveal the reaction type underlying the synthesis of the nuclei. The experience gained in this experiment will serve as a basis for future experiments to study still heavier elements at the velocity filter SHIP. Searches for element 120 in fusion-evaporation reactions of a 54Cr beam with 248Cm targets were studied later at SHIP and progress in the analysis will be

  8. Waveform design for cognitive radar: target detection in heavy clutter

    NASA Astrophysics Data System (ADS)

    Kirk, Benjamin H.; Narayanan, Ram M.; Martone, Anthony F.; Sherbondy, Kelly D.

    2016-05-01

    In many applications of radar systems, detection of targets in environments with heavy clutter and interference can be difficult. It is desired that a radar system should detect targets at a further range as well as be able to detect these targets with very few false positive or negative readings. In a cognitive radar system, there are ways that these negative effects can be mitigated and target detection can be significantly improved. An important metric to focus on for increasing target detectability is the signal-to-clutter ratio (SCR). Cognitive radar offers solutions to issues such as this with the use of a priori knowledge of targets and environments as well as real time adaptations. A feature of cognitive radar that is of interest is the ability to adapt and optimize transmitted waveforms to a given situation. A database is used to hold a priori and dynamic knowledge of the operational environment and targets to be detected, such as clutter characteristics and target radar cross-section (RCS) estimations. Assuming this knowledge is available or can be estimated in real-time, the transmitted waveform can be tailored using methods such as transmission of a spectrum corresponding to the target-to-clutter ratio (TCR). These methods provide significant improvement in distinguishing targets from clutter or interference.

  9. Fusion-fission Study at JAEA for Heavy-element Synthesis

    NASA Astrophysics Data System (ADS)

    Nishio, K.

    Fission fragment mass distributions were measured in the heavy-ion induced fission using 238U target nucleus. The mass distribu- tions changed drastically with incident energy. The results are explained by a change of the ratio between fusion and qasifission with nuclear orientation. A calculation based on a fluctuation dissipation model reproduced the mass distributions and their inci- dent energy dependence. Fusion probability was determined in the analysis. Evaporation residue cross sections were calculated with a statistical model in the reactions of 30Si+238U and 34S+238U using the obtained fusion probability in the entrance channel. The results agree with the measured cross sections of 263,264Sg and 267,268Hs, produced by 30Si+238U and 34S+238U, respectively. It is also suggested that the sub-barrier energies can be used for heavy element synthesis.

  10. Heavy element stable isotope ratios: analytical approaches and applications.

    PubMed

    Tanimizu, Masaharu; Sohrin, Yoshiki; Hirata, Takafumi

    2013-03-01

    Continuous developments in inorganic mass spectrometry techniques, including a combination of an inductively coupled plasma ion source and a magnetic sector-based mass spectrometer equipped with a multiple-collector array, have revolutionized the precision of isotope ratio measurements, and applications of inorganic mass spectrometry for biochemistry, geochemistry, and marine chemistry are beginning to appear on the horizon. Series of pioneering studies have revealed that natural stable isotope fractionations of many elements heavier than S (e.g., Fe, Cu, Zn, Sr, Ce, Nd, Mo, Cd, W, Tl, and U) are common on Earth, and it had been widely recognized that most physicochemical reactions or biochemical processes induce mass-dependent isotope fractionation. The variations in isotope ratios of the heavy elements can provide new insights into past and present biochemical and geochemical processes. To achieve this, the analytical community is actively solving problems such as spectral interference, mass discrimination drift, chemical separation and purification, and reduction of the contamination of analytes. This article describes data calibration and standardization protocols to allow interlaboratory comparisons or to maintain traceability of data, and basic principles of isotope fractionation in nature, together with high-selectivity and high-yield chemical separation and purification techniques for stable isotope studies.

  11. Progress in Target Physics and Design for Heavy Ion Fusion

    NASA Astrophysics Data System (ADS)

    Callahan-Miller, Debra

    1999-11-01

    Two-dimensional, integrated calculations of a close-coupled version of the distributed radiator, heavy ion target predict gain 130 from 3.3 MJ of beam energy. To achieve these results, the case-to-capsule ratio was decreased by about 25% from our previous targets.(M. Tabak, D. Callahan-Miller, Phys. Plasmas, 5, 1895 (1998).) The smaller hohlraum results in smaller beam spots than had been previously assumed; this puts renewed emphasis on controlling emittance growth in the accelerator and on space-charge neutralization in the reactor chamber. These targets are robust--changes in ion range and ion stopping model can be accommodated by changes in the target. Single-mode Rayleigh-Taylor growth rates for this capsule are smaller than those for at least one NIF design. As a result, stability issues for the heavy ion capsule can be settled on NIF. The close-coupled target also opens up the possibility of a high gain Engineering Test Facility from a 1.5-2 MJ driver; calculations predict that gain 90 is achievable from 1.75 MJ of beam energy. Gain curves, used for optimizing the system of accelerator, final focus, chamber transport, and target, are in good agreement with the two-dimensional calculations for both the ``conventional'' and close-coupled case-to-capsule ratio. Finally, we will discuss the choice of hohlraum wall material which must satisfy constraints from target physics (high opacity/low heat capacity to minimize the amount of energy in the hohlraum wall), environment and safety (low activation for recycling and waste disposal), chamber design (recovery of the material from the chamber), and target fabrication (need to produce many low cost targets per day).

  12. Application of alpha spectrometry to the discovery of new elements by heavy-ion-beam bombardment

    SciTech Connect

    Nitschke, J.M.

    1983-05-01

    Starting with polonium in 1898, ..cap alpha..-spectrometry has played a decisive role in the discovery of new, heavy elements. For even-even nuclei, ..cap alpha..-spectra have proved simple to interpret and exhibit systematic trends that allow extrapolation to unknown isotopes. The early discovery of the natural ..cap alpha..-decay series led to the very powerful method of genetically linking the decay of new elements to the well-established ..cap alpha..-emission of daughter and granddaughter nuclei. This technique has been used for all recent discoveries of new elements including Z = 109. Up to mendelevium (Z = 101), thin samples suitable for ..cap alpha..-spectrometry were prepared by chemical methods. With the advent of heavy-ion accelerators new sample preparation methods emerged. These were based on the large momentum transfer associated with heavy-ion reactions, which produced energetic target recoils that, when ejected from the target, could be thermalized in He gas. Subsequent electrical deposition or a He-jet technique yielded samples that were not only thin enough for ..cap alpha..-spectroscopy, but also for ..cap alpha..- and ..beta..-recoil experiments. Many variations of these methods have been developed and are discussed. For the synthesis of element 106 an aerosol-based recoil transport technique was devised. In the most recent experiments, ..cap alpha..-spectrometry has been coupled with the magnetic analysis of the recoils. The time from production to analysis of an isotope has thereby been reduced to 10/sup -6/ s; while it was 10/sup -1/ to 10/sup 0/ s for He-jets and 10/sup 1/ to 10/sup 3/ s for rapid chemical separations. Experiments are now in progress to synthesize super heavy elements (SHE) and to analyze them with these latest techniques. Again, ..cap alpha..-spectrometry will play a major role since the expected signature for the decay of a SHE is a sequence of ..cap alpha..-decays followed by spontaneous fission.

  13. Electron loss from fast heavy ions: Target-scaling dependence

    SciTech Connect

    DuBois, R. D.; Santos, A. C. F.; Montenegro, E. C.; Sigaud, G. M.

    2011-08-15

    The target dependence for projectile electron loss is investigated using experimental data taken from the literature. Impact energies range from a few tens of eV/u to tens of MeV/u. For energies less than several MeV/u, the target dependences are shown to be very similar, independent of projectile species and charge state. Overall, however, with increasing impact energy the cross-section dependence on the target nuclear charge systematically increases. It is shown that none of the existing cross-section target scaling models reproduce these features. A model, based on Born scaling and including both the antiscreening and screening contributions to projectile electron loss, is developed. With the inclusion of relativistic effects, which increase the contribution from both channels at high energies, and ''target saturation'' effects, which reduce the contribution from the screening term for heavy targets and lower impact energies, this model describes quite reasonably all available experimental data. A simple scaling formula that reproduces the measured atomic number and impact velocity dependences is provided. This formula is applicable for projectile electron loss in collisions with either atomic or molecular targets and for impact energies ranging from a few to tens of MeV/u.

  14. Optical model calculations of heavy-ion target fragmentation

    NASA Technical Reports Server (NTRS)

    Townsend, L. W.; Wilson, J. W.; Cucinotta, F. A.; Norbury, J. W.

    1986-01-01

    The fragmentation of target nuclei by relativistic protons and heavy ions is described within the context of a simple abrasion-ablation-final-state interaction model. Abrasion is described by a quantum mechanical formalism utilizing an optical model potential approximation. Nuclear charge distributions of the excited prefragments are calculated by both a hypergeometric distribution and a method based upon the zero-point oscillations of the giant dipole resonance. Excitation energies are estimated from the excess surface energy resulting from the abrasion process and the additional energy deposited by frictional spectator interactions of the abraded nucleons. The ablation probabilities are obtained from the EVA-3 computer program. Isotope production cross sections for the spallation of copper targets by relativistic protons and for the fragmenting of carbon targets by relativistic carbon, neon, and iron projectiles are calculated and compared with available experimental data.

  15. Elemental characterization of PM1 in a heavy traffic region

    NASA Astrophysics Data System (ADS)

    Ambade, Balram

    Eight hours samples of airborne aerosols PM1 were collected during summer (August-September) and winter (October-November) form one year 2010- 2011 in a intense traffic area of Rajnandgaon city, India. Inductively coupled plasma mass spectroscopy was employed to measure heavy metals (Hg, Cd, Ni, Pb, As). Water-soluble ions (Na+, NH4 +, K+, Ca2+, Cl-, NO3 -, and SO42-) and carbonaceous mass (elemental and organic carbon) were detected using ion chromatograph and CHN analyzer, respectively. The results indicate that the composition of PM10 on intense traffic area is highly affected by automobile emissions. Based on the chemical information, positive matrix factorization (PMF) was used to identify PM sources. A total of five source types were identified, including soil dust, vehicle emissions, sea salt, industrial emissions and secondary aerosols, and their contributions were estimated using PMF. The crustal enrichment factors (EF) were calculated using Al as a reference for the trace metal species to identify the sources

  16. Recent developments in the synthesis of super heavy elements

    NASA Astrophysics Data System (ADS)

    Ackermann, D.

    2001-04-01

    Throughout the passed two decades isotopes of the elements with atomic numbers 107-112 have been synthesized and unambiguously identified at the velocity filter SHIP at GSI. In a recent experiment at SHIP the results for element 112 have been confirmed and a third decay chain of the isotope 277112 has been observed. Cold fusion reactions using Pb- and Bi- targets and evaporation residue(ER)-α-α correlations together with an efficient separation and detection system are the major ingredients for the success of these experiments. The sensitivity limit of the set-up at GSI has reached the 1pb level. For a systematic investigation in this region of the chart of nuclei and to synthesize heavier nuclei this limit has to be pushed to even lower values. An extensive development program is pursued at SHIP in order to reach at least an order of magnitude lower cross sections. Systematic investigations, the construction of decay chain networks and mass measurements are some of the possible approaches to study the decay chains attributed to isotopes of the elements 114, 116 and 118 at Dubna and Berkeley, which are, in contrast to those observed at GSI, not connected to decays of known isotopes. For the Berkeley results, in particular, several trials of confirmation have been undertaken at various laboratories including GSI. .

  17. The Discovery of Super-Heavy Element of Atomic Number Z = 113 Nihonium and Beyond*

    NASA Astrophysics Data System (ADS)

    Morita, Kosuke

    Experimental efforts and the achievements by the Super Heavy Element Research Group in RIKEN are presented in the lecture, including a new discovery of Z = 113 element. Eventually, this element has been named officially as Nihonium (Nh), proposed by our group, in November 2016. A new effort for possible new elements Z = 119 1nd 120 is also presented.

  18. Electronic stopping power for heavy ions in hot targets

    NASA Astrophysics Data System (ADS)

    Wang, You-Nian; Ma, Teng-Cai; Gong, Ye

    1993-03-01

    An investigation on the electronic stopping power and the effective charge for a heavy ion in a hot target is made using linear-response dielectric theory. The charge distribution of the electrons bound to a projectile is determined by the Brandt-Kitagawa (BK) model [Phys. Rev. B 25, 3631 (1982)]. Some analytical expressions of the electronic stopping power and the effective charge are obtained in the limits of the low and high velocities, respectively. The theoretical results are compared with the experimental data for high-velocity ions.

  19. Seismic monitoring of heavy oil reservoirs: Rock physics and finite element modelling

    NASA Astrophysics Data System (ADS)

    Theune, Ulrich

    In the past decades, remote monitoring of subsurface processes has attracted increasing attention in geophysics. With repeated geophysical surveys one attempts to detect changes in the physical properties in the underground without directly accessing the earth. This technique has been proven to be very valuable for monitoring enhanced oil recovery programs. This thesis presents an modelling approach for the feasibility analysis for monitoring of a thermal enhanced oil recovery technique applied to heavy oil reservoirs in the Western Canadian Sedimentary Basin. In order to produce heavy oil from shallow reservoirs thermal oil recovery techniques such as the Steam Assisted Gravity Drainage (SAGD) are often employed. As these techniques are expensive and technically challenging, early detection of operational problems is without doubt of great value. However, the feasibility of geophysical monitoring depends on many factors such as the changes in the rock physical properties of the target reservoir. In order to access the feasibility of seismic monitoring for heavy oil reservoirs, a fluid-substitutional rock physical study has been carried out to simulate the steam injection. The second modelling approach is based on a modified finite element algorithm to simulate the propagation of elastic waves in the earth, which has been developed independently in the framework of this thesis. The work summarized in this thesis shows a possibility to access the feasibility of seismic monitoring for heavy oil reservoirs through an extensive rock-physical study. Seismic monitoring is a useful tool in reservoir management decision process. However, the work reported here suggests that seismic monitoring of SAGD processes in the heavy oil reservoirs of the Western Canadian Sedimentary Basin is only feasible in shallow, unconsolidated deposits. For deeper, but otherwise geological similar reservoirs, the SAGD does not create a sufficient change in the rock physical properties to be

  20. Heavy and Superheavy Elements Production in High Intensive Neutron Fluxes of Explosive Process

    NASA Astrophysics Data System (ADS)

    Lutostansky, Yu. S.; Lyashuk, V. I.; Panov, I. V.

    2015-06-01

    Mathematical model of heavy and superheavy nuclei production in intensive pulsed neutron fluxes of explosive process is developed. The pulse character of the process allows dividing it in time into two stages: very short rapid process of multiple neutron captures with higher temperature and very intensive neutron fluxes, and relatively slower process with lesser temperature and neutron fluxes. The model was also extended for calculation of the transuranium yields in nuclear explosions takes into account the adiabatic character of the process, the probabilities of delayed fission, and the emission of delayed neutrons. Also the binary starting target isotopes compositions were included. Calculations of heavy transuranium and transfermium nuclei production were made for "Mike", "Par" and "Barbel" experiments, performed in USA. It is shown that the production of transfermium neutron-rich nuclei and superheavy elements with A ~ 295 is only possible when using binary mixture of starting isotopes with the significant addition of heavy components, such as long-lived isotopes of curium, or californium.

  1. The Importance of Closed Shell Structures in the Synthesis of Super Heavy Elements

    NASA Astrophysics Data System (ADS)

    Hamilton, J. H.; Hofmann, S.; Oganessian, Y. T.

    2014-09-01

    In 1965, macroscopic models predicted that nuclei beyond Z ~ 100 could not be synthesized because their fission barrier would go to zero. Then came microscopic models with shell corrections. Microscopic-macroscopic models predicted large gaps in the single-particle energy levels for protons and neutrons at Z = 102, 108 and N = 152, 162 for deformed shapes. The reinforcement of the Z = 102, N = 152 and Z = 108, N = 162 level gaps at the same deformations provided the stability for nuclei in these regions to be observed. Also predicted were shell gaps for spherical shapes for N = 184 and Z = 114, 120 or 126 forming an ``Island of Stability'' with very long half lives for fission and alpha decay. Cold fusion reactions involving beams of Ca to Zn and targets of stable 208Pb and 209Bi were pioneered at GSI and used to synthesize new elements for Z = 107 to 112 and in Japan a new isotope of 113. Hot fusion reactions between radioactive actinide targets and neutron-rich 48Ca beams were pioneered in JINR leading to the synthesis of new elements with Z = 113 to 118. Data showing the importance of reinforcement of the Z = 102, N = 152 and Z = 108, N = 162 single particle level gaps at the same deformation and Z = 114-126, N = 184 shell gaps in the synthesis of super heavy elements 107 to 118 will be presented along with the latest results on their synthesis.

  2. The Zintl Chemistry of the Heavy Tetrel Elements

    SciTech Connect

    Klem, Michael Thomas

    2002-12-31

    Exploration of the alkali metal/alkaline-earth metal/heavy tetrel (Sn or Pb) systems has revealed a vast array of new chemistry and novel structure types. The structures and properties of these new materials have been studied in an attempt to understand the chemistry of these and other related systems. The first phase reported is Rb4Pb9 (K4Pb9 type). The compound contains two different types of Pb94- deltahedra, a monocapped square pyramid and a distorted tricapped trigonal prism. Both cluster geometries correspond to a nido assignment even though the tricapped trigonal prism is not the classic Wade's rules nido deltahedron expected for a monocapped square antiprism. Also, a series of compounds that contain square pyramidal Tt5 polyanions of tin and lead has been obtained in alkaline-earth or rare-earth metal-tetrel systems by direct fusion of the elements to yield Sr3Sn5, Ba3Pb5, and La3Sn5. These phases contain square pyramidal clusters of the tetrel elements that are weakly interlinked into chains via two types of longer intercluster interactions that are mediated by bridging cations and substantially influenced by cation size and the free electron count. Attempts at incorporating another main-group element to form heteroatomic clusters were also successful. In the case of A5InPb8 (A = K, Rb), the compounds contain clusters composed of two Pb4 tetrahedra that are interbridged by a lone μ6-In atom. The InPb8 units are weakly interlinked into sheets in the ab plane by long intercluster Pb-Pb interactions. Using As led to the formation of the compound K5As3Pb3 which is made up of As3Pb35- crown clusters that can be likened to a 6-atom hypho-cluster based on the tricapped trigonal parent as the closo

  3. Direct measurements of the stopping power for antiprotons of light and heavy targets

    SciTech Connect

    Mo Uggerho Bluhme, H.; Knudsen, H.; Mikkelsen, U.; Paludan, K.; Morenzoni, E.

    1997-10-01

    Measurements of antiproton stopping powers around the stopping-power maximum are presented for targets of Al, Si, Ti, Cu, Ag, Ta, Pt, and Au. The Low Energy Antiproton Ring antiproton beam of 5.9 MeV is degraded to 50{endash}700 keV, and the energy loss is found by measuring the antiproton velocity before and after the target. Target thicknesses have been determined accurately by weighing and Rutherford backscattering techniques. The antiproton stopping powers are found to be reduced by around 35{percent} for both light and heavy elements near the electronic stopping-power maximum as compared to the equivalent proton stopping power. The antiproton stopping powers and the Barkas effect; that is, the difference in stopping power between protons and antiprotons is compared to theoretical estimates, based on a harmonic-oscillator model and an electron-gas model, and good agreement is obtained. {copyright} {ital 1997} {ital The American Physical Society}

  4. A finite element numerical solution of the multispecies relativistic heavy ion transport equations

    NASA Astrophysics Data System (ADS)

    Dandini, Vincent John

    1998-09-01

    The energy deposition characteristics of heavy ions and the availability of modern particle accelerators, have sparked a revival of interest in the use of these particles as a treatment tool for certain types of cancers. The presence of these high energy particles in the cosmic radiation has also been a concern of spacecraft designers since the advent of space flight. Collisions between projectile ions and the nuclei of target atoms can result in ion fragments that are different from the original projectile species. The energy deposition characteristics of these fragments differ from those of the original ion in a manner that increases their range beyond that of the original particle. Projectile loss due to the fragmentation process also affects the dose deposition profile in a target. An accurate dose calculation requires that these effects be taken into account. In order to bypass difficulties associated with Monte Carlo calculations and traditional discretization methods, the recently developed exponential discontinuous (ED) finite element technique has been applied to the calculation of the dose deposition by relativistic heavy ion projectiles and their fragments. The ELDRHIT code package has been developed to solve the relativistic heavy ion transport equations in space and energy using the straight ahead approximation with conservation of velocity. Energy loss is treated with the continuous slowing down approximation. Absorption and fragmentation cross sections and stopping powers are taken as piece-wise constant in each phase space cell. Initial results indicated that the ED method could not capture the Bragg peak of the primary ion. This result is due to numerical diffusion of the particle energy inherent to the method. However, a hybrid approach, using a characteristic based solution for the primary particle coupled with an ED solution for the fragments, has demonstrated very good agreement with experimental results.

  5. Edward A. Bouchet Award: Heavy element synthesis in the Universe

    NASA Astrophysics Data System (ADS)

    Ramirez-Ruiz, Enrico

    2017-01-01

    The source of about half of the heaviest elements in the Universe has been a mystery for a long time. Although the general picture of element formation is well understood, many questions about the nuclear physics processes and particularly the astrophysical details remain to be answered. Here I focus on advances in our understanding of the origin of the heaviest and rarest elements in the Universe.

  6. Comment on 'Heavy element production in inhomogeneous big bang nucleosynthesis'

    SciTech Connect

    Rauscher, Thomas

    2007-03-15

    The work of Matsuura et al. [Phys. Rev. D 72, 123505 (2005)] claims that heavy nuclei could have been produced in a combined p- and r-process in very high baryon density regions of an inhomogeneous big bang. However, they do not account for observational constraints and previous studies which show that such high baryon density regions did not significantly contribute to big bang abundances.

  7. Heavy element synthesis in the oldest stars and the early Universe.

    PubMed

    Cowan, John J; Sneden, Christopher

    2006-04-27

    The first stars in the Universe were probably quite different from those born today. Composed almost entirely of hydrogen and helium (plus a tiny trace of lithium), they lacked the heavier elements that determine the formation and evolution of younger stars. Although we cannot observe the very first stars--they died long ago in supernovae explosions--they created heavy elements that were incorporated into the next generation. Here we describe how observations of heavy elements in the oldest surviving stars in our Galaxy's halo help us understand the nature of the first stars--those responsible for the chemical enrichment of our Galaxy and Universe.

  8. NO HEAVY-ELEMENT DISPERSION IN THE GLOBULAR CLUSTER M92

    SciTech Connect

    Cohen, Judith G.

    2011-10-20

    Although there have been recent claims that there is a large dispersion in the abundances of the heavy neutron capture elements in the old Galactic globular cluster M92, we show that the measured dispersion for the absolute abundances of four of the rare earth elements within a sample of 12 luminous red giants in M92 ({<=}0.07 dex) does not exceed the relevant sources of uncertainty. As expected from previous studies, the heavy elements show the signature of the r-process. Their abundance ratios are essentially identical to those of M30, another nearby globular cluster of similar metallicity.

  9. Unraveling heavy oil desulfurization chemistry: targeting clean fuels.

    PubMed

    Choudhary, Tushar V; Parrott, Stephen; Johnson, Byron

    2008-03-15

    The sulfur removal chemistry of heavy oils has been unraveled by systematically investigating several heavy oils with an extremely wide range of properties. The heavy oil feed and product properties have been characterized by advanced analytical methods, and these properties have been related to the sulfur conversion data observed in pilot hydrotreating units. These studies coupled with kinetic treatment of the data have revealed that the desulfurization chemistry of heavy oils is essentially controlled by the strongly inhibiting three and larger ring aromatic hydrocarbon content and surprisingly not by the content of the "hard-to-remove" sulfur compounds. Such enhanced understanding of the heavy oil sulfur removal is expected to open new avenues for catalyst/process optimization for heavy oil desulfurization and thereby assist the efficent production of clean transporation fuels.

  10. Fraction distribution and risk assessment of heavy metals and trace elements in sediments of Lake Uluabat.

    PubMed

    Katip, Aslıhan; Karaer, Feza; Başkaya, Hüseyin Savaş; Ileri, Saadet; Sarmaşik, Sonay

    2012-09-01

    To examine the status and risk of heavy metal pollution, the distribution of As, Cd, Cr, Ni, and Pb in the sediment of Lake Uluabat was characterized. The present study used a four-stage method to assess the ecotoxicological effects of the heavy metal and trace elements fractions in the sediment of Lake Uluabat. Total Cr and Ni concentrations in the sediment were determined to have exceeded the severe effect level (SEL) limit values. The percentages of the variable fractions of Cr and Ni were below 10%. Because of this reason, they were not defined to have a high risk. The relationships among the physicochemical parameters, heavy metals and trace elements in water and sediment were determined statistically. Pb, Cd, and As in the water were found in relation with some of the fractions. Moreover, it was thought that the amounts of the elements of As releasing into the water might be increased due to their relations with the physicochemical parameters.

  11. Heavy-element abundances in the classical barium star HR 774

    NASA Astrophysics Data System (ADS)

    Tomkin, J.; Lambert, D. L.

    1983-10-01

    Low-noise high-resolution Digicon and Reticon spectra of HR 774 are analyzed to determine abundances for all accessible heavy elements in the visual and near-infrared. The authors find evidence of departures from LTE as large as 0.5 dex affecting the low-excitation neutral lines of heavy elements in HR 774 and the standard star (β Gem). These severe effects cancel in a comparison of HR 774 with β Gem. Abundances of 19 heavy elements (Z ≥ 37) are determined and used to derive s-process overabundances. The predicted s-process abundances fit the derived s-process abundances remarkably well. The pattern of s-process abundances is consistent with the 13C(α, n)16O reaction as the neutron source and excludes the 22Ne(α, n)25Mg reaction.

  12. CORONAL SOURCES, ELEMENTAL FRACTIONATION, AND RELEASE MECHANISMS OF HEAVY ION DROPOUTS IN THE SOLAR WIND

    SciTech Connect

    Weberg, Micah J.; Lepri, Susan T.; Zurbuchen, Thomas H. E-mail: slepri@umich.edu

    2015-03-10

    The elemental abundances of heavy ions (masses larger than He) in the solar wind provide information about physical processes occurring in the corona. Additionally, the charge state distributions of these heavy ions are sensitive to the temperature profiles of their respective source regions in the corona. Heavy ion dropouts are a relatively new class of solar wind events identified by both elemental and ionic charge state distributions. We have shown that their origins lie in large, closed coronal loops where processes such as gravitational settling dominate and can cause a mass-dependent fractionation pattern. In this study we consider and attempt to answer three fundamental questions concerning heavy ion dropouts: (1) 'where are the source loops located in the large-scale corona?'; (2) 'how does the interplay between coronal processes influence the end elemental abundances?'; and (3) 'what are the most probable release mechanisms'? We begin by analyzing the temporal and spatial variability of heavy ion dropouts and their correlation with heliospheric plasma and magnetic structures. Next we investigate the ordering of the elements inside dropouts with respect to mass, ionic charge state, and first ionization potential. Finally, we discuss these results in the context of the prevailing solar wind theories and the processes they posit that may be responsible for the release of coronal plasma into interplanetary space.

  13. Prospects of heavy and superheavy element production via inelastic nucleus-nucleus collisions - from 238U+238U to18O+254Es

    NASA Astrophysics Data System (ADS)

    Schädel, Matthias

    2016-12-01

    Multi-nucleon transfer reactions, frequently termed deep-inelastic, between heavy-ion projectiles and actinide targets provide prospects to synthesize unknown isotopes of heavy actinides and superheavy elements with neutron numbers beyond present limits. The 238U on 238U reaction, which revealed essential aspects of those nuclear reactions leading to surviving heavy nuclides, mainly produced in 3n and 4n evaporation channels, is discussed in detail. Positions and widths of isotope distributions are compared. It is shown, as a general rule, that cross sections peak at irradiation energies about 10% above the Coulomb barrier. Heavy target nuclei are essential for maximizing cross sections. Experimental results from the 238U on 248Cm reaction, including empirical extrapolations, are compared with theoretical model calculations predicting relatively high cross sections for neutron-rich nuclei. Experiments to test the validity of such predictions are proposed. Comparisons between rather symmetric heavy-ion reactions like 238U on 248Cm (or heavier targets up to 254Es) with very asymmetric ones like 18O on 254Es reveal that the ones with 238U as a projectile have the highest potential in the superheavy element region while the latter ones can be advantageous for the synthesis of heavy actinide isotopes. Concepts for highly efficient recoil separators designed for transfer products are presented.

  14. [Study on species and valence state of heavy metals and deleterious elements of mineral medicine].

    PubMed

    Han, Xu; Luo, Jiao-yang; Liu, Qiu-tao; Li, Yan-jun; Xie, Yan-jun; Yang, Shi-hai; Yang, Mei-hua

    2015-12-01

    As an important part of traditional Chinese medicine (TCM), mineral medicine plays an irreplaceable role. However, little has been reported on its species and valence state of heavy metals and deleterious elements, and also the relevance to pharmacological effect and toxicology. The present paper, in a new perspective, summarized the determination of the species and valence state of heavy metals and deleterious elements in recent years, discussed the progress of the pharmacological effect and toxicology, and prospected for future study which might provide reference for mineral medicine.

  15. Heavy Element Abundances in Planetary Nebulae from Deep Optical Echelle Spectroscopy

    NASA Astrophysics Data System (ADS)

    Mashburn, Amanda; Sterling, Nicholas C.; Dinerstein, Harriet L.; Garofali, Kristen; Jensema, Rachael; Turbyfill, Amanda; Wieser, Hannah-Marie N.; Reed, Evan C.; Redfield, Seth

    2016-01-01

    We present the abundances of neutron(n)-capture elements (atomic number Z > 30) and iron determined from deep optical echelle spectroscopy of 14 Galactic planetary nebulae (PNe). The spectra were obtained with the 2D-coudé spectrograph on the 2.7-m Harlan J. Smith telescope at McDonald Observatory. The abundances of n-capture elements can be enhanced in PNe due to slow n-capture nucleosynthesis in the progenitor asymptotic giant branch (AGB) stars. The high spectral resolution of these data (R = 36,700) allow most n-capture element emission lines to be resolved from other nebular and telluric features. We detect Kr in all of the observed PNe (with multiple ions detected in several objects), while Br, Rb, and Xe were each detected in 4--5 objects. Using the new Kr ionization correction factors (ICFs) of Sterling et al. (2015, ApJS, 218, 25), we find [Kr/O] abundances ranging from 0.05 to 1.1 dex. We utilize approximate ICFs for the other n-capture elements, and find slightly lower enrichments for Br and Rb (-0.1 to 0.7 dex), while Xe is enhanced relative to solar by factors of two to 30. The [Xe/Kr] ratios range from -0.3 to 1.4 dex, indicating a significant range in neutron exposures in PN progenitor stars. Interestingly, the largest [Xe/Kr] ratio is found in the thick-disk PN NGC 6644, which has a lower metallicity than the other observed PNe. We detect iron emission lines in all but one target. Fe can be depleted into dust grains in ionized nebulae, and its abundance thus provides key information regarding dust-to-gas ratios and grain destruction processes. We find that [Fe/O] ranges from -1.3 to -0.7 dex in the observed PNe, a smaller spread of depletion factors than found in recent studies (Delgado-Inglada & Rodriguez 2014, ApJ, 784, 173) though this may be due in part to our smaller sample. These data are part of a larger study of heavy elements in PNe, which will provide more accurate determinations of n-capture element abundances than previous estimates in

  16. Surrogate Nuclear Reactions and the Origin of the Heavy Elements

    SciTech Connect

    Escher, J; Ahle, L; Bernstein, L; Church, J; Dietrich, F; Forssen, C; Hoffman, R

    2004-07-13

    An innovative method for indirectly determining reaction cross sections via Surrogate Nuclear Reactions is presented. Exploring indirect approaches for obtaining reaction cross sections is important since a large number of nuclear reactions relevant to astrophysics cannot be measured with currently available techniques. A program is outlined for developing a comprehensive framework for planning and interpreting experiments that can yield the cross sections of interest. The applications will focus on reactions involving unstable nuclei that play a key role in the production of the elements between iron and uranium.

  17. The Heavy Element Abundance in Groups of Galaxies

    NASA Technical Reports Server (NTRS)

    David, Laurence

    2000-01-01

    Over the past few years we have analyzed a sample of clusters observed by the Advanced Spacecraft for Cosmology Astrophysics (ASCA) X-ray satellite. We performed spatially resolved X-ray spectroscopy of a sample of 18 relaxed clusters of galaxies with gas temperatures below 4 keV. The spectral analysis was done using ASCA/SIS (Solid state Imaging Spectrometer) data combined with imaging data from ROSAT/PSPC (German acronym for X-ray satellite/Position Sensitive Proportional Counter) and Einstein/IPC (Imaging Proportional Counter) observations. We derived temperature profiles using single-temperature fits for all of the clusters in the sample, and also corrected for the presence of cold gas in the center of so-called 'cooling flow' clusters. For all of the clusters in the sample we derived Si and Fe abundance profiles. For a few of the clusters we also were able to derive Ne and S abundance profiles. We compared the elemental abundances derived at similar overdensities in all of the clusters in the sample. We also compared element mass-to-light ratios for the entire sample. We concluded that the preferential accretion of low entropy, low abundance gas into the potentials of groups and cold clusters can explain most of the observed trends in metallicity. In addition, we discussed the importance of preheating of the intracluster medium by Type II supernovae on the cluster scaling relations.

  18. The Heavy Element Abundance in Groups of Galaxies

    NASA Technical Reports Server (NTRS)

    David, Laurence

    2000-01-01

    Over the past few years we have analyzed a sample of clusters observed by the Advanced Spacecraft for Cosmology Astrophysics (ASCA) X-ray satellite. We performed spatially resolved X-ray spectroscopy of a sample of 18 relaxed clusters of galaxies with gas temperatures below 4 keV. The spectral analysis was done using ASCA/SIS (Solid state Imaging Spectrometer) data combined with imaging data from ROSAT/PSPC (German acronym for X-ray satellite/Position Sensitive Proportional Counter) and Einstein/IPC (Imaging Proportional Counter) observations. We derived temperature profiles using single-temperature fits for all of the clusters in the sample, and also corrected for the presence of cold gas in the center of so-called 'cooling flow' clusters. For all of the clusters in the sample we derived Si and Fe abundance profiles. For a few of the clusters we also were able to derive Ne and S abundance profiles. We compared the elemental abundances derived at similar overdensities in all of the clusters in the sample. We also compared element mass-to-light ratios for the entire sample. We concluded that the preferential accretion of low entropy, low abundance gas into the potentials of groups and cold clusters can explain most of the observed trends in metallicity. In addition, we discussed the importance of preheating of the intracluster medium by Type II supernovae on the cluster scaling relations.

  19. Standardless Quantification of Heavy Elements by Electron Probe Microanalysis.

    PubMed

    Moy, Aurélien; Merlet, Claude; Dugne, Olivier

    2015-08-04

    Absolute Mα and Mβ X-ray intensities were measured for the elements Pt, Au, Pb, U, and Th by electron impact for energies ranging from 6 to 38 keV. Experimental data were obtained by measuring the X-ray intensity emitted from bulk samples with an electron microprobe using high-resolution wavelength-dispersive spectrometers. Recorded X-ray intensities were converted into absolute X-ray yields by evaluation of the detector efficiency and then compared with X-ray intensities calculated by means of Monte Carlo simulations. Simulated Mα and Mβ X-ray intensities were found to be in good agreement with the measurements, allowing their use in standardless quantification methods. A procedure and a software program were developed to accurately obtain virtual standard values. Standardless quantifications of Pb and U were tested on standards of PbS, PbTe, PbCl2, vanadinite, and UO2.

  20. Recent Investigations of Heavy Elements (37{<=}Z{<=}92)

    SciTech Connect

    Biemont, E.

    2011-05-11

    The present paper is an update and extension of previous compilations [1, 2] and it describes recent progress regarding the investigation of the radiative properties of the elements and ions (first three ionization stages) of the fifth and sixth rows of the periodic table and of the rare earths (mostly the lanthanides). From a combination of experimental radiative lifetimes obtained with laser spectroscopy and of theoretical branching fractions calculated with a quasirelativistic Hartree-Fock approach taking configuration interaction and core-polarization effects into account, transition probabilities have been deduced for a large number of transitions of astrophysical interest. Some new results are briefly described here. The numerical values are stored in the databases DESIRE and DREAM, which are developped and progressively updated on a web site of Mons University in Belgium.

  1. Marriage of heavy main group elements with π-conjugated materials for optoelectronic applications.

    PubMed

    Parke, Sarah M; Boone, Michael P; Rivard, Eric

    2016-08-07

    This review article summarizes recent progress in the synthesis and optoelectronic properties of conjugated materials containing heavy main group elements from Group 13-16 as integral components. As will be discussed, the introduction of these elements can promote novel phosphorescent behavior and support desirable molecular and polymeric properties such as low optical band gaps and high charge mobilities for photovoltaic and thin film transistor applications.

  2. Nuclear Hexadecapole Deformation Effects on the Production of Super-Heavy Elements

    NASA Astrophysics Data System (ADS)

    Wang, Nan; Dou, Liang; Zhao, En-Guang; Werner, Scheid

    2010-06-01

    We investigate the effects of the nuclear hexadecapole deformations on the interaction potentials between nuclei, the driving potentials and the fusion probabilities for some cold fusion reactions leading to super-heavy elements. It is found that nuclear hexadecapole deformations change significantly the structure of the driving potentials and the fusion probabilities for some reaction channels.

  3. Heavy-Ion Fusion Mechanism and Predictions of Super-Heavy Elements Production

    SciTech Connect

    Abe, Yasuhisa; Shen Caiwan; Boilley, David

    2009-08-26

    Fusion process is shown to firstly form largely deformed mono-nucleus and then to undergo diffusion in two-dimensions with the radial and mass-asymmetry degrees of freedom. Examples of prediction of residue cross sections are given for the elements with Z = 117 and 118.

  4. NEW HUBBLE SPACE TELESCOPE OBSERVATIONS OF HEAVY ELEMENTS IN FOUR METAL-POOR STARS

    SciTech Connect

    Roederer, Ian U.; Thompson, Ian B.; Lawler, James E.; Sobeck, Jennifer S.; Beers, Timothy C.; Cowan, John J.; Frebel, Anna; Ivans, Inese I.; Schatz, Hendrik; Sneden, Christopher

    2012-12-15

    Elements heavier than the iron group are found in nearly all halo stars. A substantial number of these elements, key to understanding neutron-capture nucleosynthesis mechanisms, can only be detected in the near-ultraviolet. We report the results of an observing campaign using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope to study the detailed heavy-element abundance patterns in four metal-poor stars. We derive abundances or upper limits from 27 absorption lines of 15 elements produced by neutron-capture reactions, including seven elements (germanium, cadmium, tellurium, lutetium, osmium, platinum, and gold) that can only be detected in the near-ultraviolet. We also examine 202 heavy-element absorption lines in ground-based optical spectra obtained with the Magellan Inamori Kyocera Echelle Spectrograph on the Magellan-Clay Telescope at Las Campanas Observatory and the High Resolution Echelle Spectrometer on the Keck I Telescope on Mauna Kea. We have detected up to 34 elements heavier than zinc. The bulk of the heavy elements in these four stars are produced by r-process nucleosynthesis. These observations affirm earlier results suggesting that the tellurium found in metal-poor halo stars with moderate amounts of r-process material scales with the rare earth and third r-process peak elements. Cadmium often follows the abundances of the neighboring elements palladium and silver. We identify several sources of systematic uncertainty that must be considered when comparing these abundances with theoretical predictions. We also present new isotope shift and hyperfine structure component patterns for Lu II and Pb I lines of astrophysical interest.

  5. Matrix elements of Δ B =0 operators in heavy hadron chiral perturbation theory

    NASA Astrophysics Data System (ADS)

    Lee, Jong-Wan

    2015-05-01

    We study the light-quark mass and spatial volume dependence of the matrix elements of Δ B =0 four-quark operators relevant for the determination of Vu b and the lifetime ratios of single-b hadrons. To this end, one-loop diagrams are computed in the framework of heavy hadron chiral perturbation theory with partially quenched formalism for three light-quark flavors in the isospin limit; flavor-connected and -disconnected diagrams are carefully analyzed. These calculations include the leading light-quark flavor and heavy-quark spin symmetry breaking effects in the heavy hadron spectrum. Our results can be used in the chiral extrapolation of lattice calculations of the matrix elements to the physical light-quark masses and to infinite volume. To provide insight on such chiral extrapolation, we evaluate the one-loop contributions to the matrix elements containing external Bd, Bs mesons and Λb baryon in the QCD limit, where sea and valence quark masses become equal. In particular, we find that the matrix elements of the λ3 flavor-octet operators with an external Bd meson receive the contributions solely from connected diagrams in which current lattice techniques are capable of precise determination of the matrix elements. Finite volume effects are at most a few percent for typical lattice sizes and pion masses.

  6. Predicting target displacements using ultrasound elastography and finite element modeling.

    PubMed

    op den Buijs, Jorn; Hansen, Hendrik H G; Lopata, Richard G P; de Korte, Chris L; Misra, Sarthak

    2011-11-01

    Soft tissue displacements during minimally invasive surgical procedures may cause target motion and subsequent misplacement of the surgical tool. A technique is presented to predict target displacements using a combination of ultrasound elastography and finite element (FE) modeling. A cubic gelatin/agar phantom with stiff targets was manufactured to obtain pre- and post-loading ultrasound radio frequency (RF) data from a linear array transducer. The RF data were used to compute displacement and strain images, from which the distribution of elasticity was reconstructed using an inverse FE-based approach. The FE model was subsequently used to predict target displacements upon application of different boundary and loading conditions to the phantom. The influence of geometry was investigated by application of the technique to a breast-shaped phantom. The distribution of elasticity in the phantoms as determined from the strain distribution agreed well with results from mechanical testing. Upon application of different boundary and loading conditions to the cubic phantom, the FE model-predicted target motion were consistent with ultrasound measurements. The FE-based approach could also accurately predict the displacement of the target upon compression and indentation of the breast-shaped phantom. This study provides experimental evidence that organ geometry and boundary conditions surrounding the organ are important factors influencing target motion. In future work, the technique presented in this paper could be used for preoperative planning of minimally invasive surgical interventions.

  7. Effects of heavy-element settling on solar neutrino fluxes and interior structure

    NASA Technical Reports Server (NTRS)

    Proffitt, Charles R.

    1994-01-01

    We consider the effects of gravitational settling of both He and heavier elements on the predicted solar neutrino fluxes and interior sound speed and density profiles. We find that while the structural changes that result from the inclusion of both He and heavy-element settling are only slightly larger than the changes resulting from the inclusion of He settling alone, the additional increases in expected neutrino fluxes are of comparable size. Our preferred model with both He and heavy-element settling has neutrino count rates of 9.0 SNU for Cl-37 detectors and 137 SNU for Ga-71 detectors, as compared to 7.1 and 127 SNU for a comparable model without any diffusive separation, or 8.0 and 132 SNU for a model that includes He settling alone. We suggest that the correction factors by which the predicted neutrino fluxes of solar models calculated without including the effects of diffusion should be multiplied are 1.25 +/- 0.08 for Cl detectors, 1.07 +/- 0.02 for Ga detectors, and 1.28 +/- 0.09 for the B-8 flux (1 sigma errors). Comparison of internal sound speed and density profiles strongly suggests that the additional changes in calculated p-mode oscillation frequencies due to the inclusion of heavy-element settling will be small compared to the changes that result from He settling alone, especially for the higher degree modes. All models with diffusive separation give much better agreement with the observed depth of the convection zone than do nondiffusive models. The model that includes both He and heavy-element settling requires an initial He mass fraction Y = 0.280 and has a surface He abundance of Y = 0.251 at the solar age.

  8. ON THE VOLATILE ENRICHMENTS AND HEAVY ELEMENT CONTENT IN HD189733b

    SciTech Connect

    Mousis, O.; Petit, J.-M.; Picaud, S.; Lunine, J. I.; Zahnle, K.; Marley, M. S.; Biennier, L.; Mitchell, J. B. A.; Cordier, D.; Georges, R.; Johnson, T. V.; Boudon, V.; Devel, M.; Griffith, C.; Iro, N.

    2011-02-01

    Favored theories of giant planet formation center around two main paradigms, namely the core accretion model and the gravitational instability model. These two formation scenarios support the hypothesis that the giant planet metallicities should be higher or equal to that of the parent star. Meanwhile, spectra of the transiting hot Jupiter HD189733b suggest that carbon and oxygen abundances range from depleted to enriched with respect to the star. Here, using a model describing the formation sequence and composition of planetesimals in the protoplanetary disk, we determine the range of volatile abundances in the envelope of HD189733b that is consistent with the 20-80 M{sub +} of heavy elements estimated to be present in the planet's envelope. We then compare the inferred carbon and oxygen abundances to those retrieved from spectroscopy, and we find a range of supersolar values that directly fit both spectra and internal structure models. In some cases, we find that the apparent contradiction between the subsolar elemental abundances and the mass of heavy elements predicted in HD189733b by internal structure models can be explained by the presence of large amounts of carbon molecules in the form of polycyclic aromatic hydrocarbons and soots in the upper layers of the envelope, as suggested by recent photochemical models. A diagnostic test that would confirm the presence of these compounds in the envelope is the detection of acetylene. Several alternative hypotheses that could also explain the subsolar metallicity of HD189733b are formulated: the possibility of differential settling in its envelope, the presence of a larger core that did not erode with time, a mass of heavy elements lower than the one predicted by interior models, a heavy element budget resulting from the accretion of volatile-poor planetesimals in specific circumstances, or the combination of all these mechanisms.

  9. Heavy metals and rare earth elements source-sink in some Egyptian cigarettes as determined by neutron activation analysis.

    PubMed

    Nada, A; Abdel-Wahab, M; Sroor, A; Abdel-Haleem, A S; Abdel-Sabour, M F

    1999-07-01

    Heavy metals and rare earth elements in two types of cigarettes were studied. The contents of trace elements were determined by using delayed neutron activation analysis. In the present study 11 elements have been detected in popular and fine brand cigarettes marketed in Egypt. Evaluation of these elements with their potential hazards for smokers is briefly discussed. The material balance (source and sink) for each element was determined. Also the ratio of element recovery to the total amount was assessed.

  10. Cosmological quantum chromodynamics, neutron diffusion, and the production of primordial heavy elements

    NASA Technical Reports Server (NTRS)

    Applegate, J. H.; Hogan, Craig J.; Scherrer, R. J.

    1988-01-01

    A simple one-dimensional model is used to describe the evolution of neutron density before and during nucleosynthesis in a high-entropy bubble left over from the cosmic quark-hadron phase transition. It is shown why cosmic nucleosynthesis in such a neutron-rich environment produces a surfeit of elements heavier than lithium. Analytical and numerical techniques are used to estimate the abundances of carbon, nitrogen, and heavier elements up to Ne-22. A high-density neutron-rich region produces enough primordial N-14 to be observed in stellar atmospheres. It shown that very heavy elements may be created in a cosmological r-process; the neutron exposure in the neutron-rich regions is large enough for the Ne-22 to trigger a catastrophic r-process runaway in which the quantity of heavy elements doubles in much less than an expansion time due to fission cycling. A primordial abundance of r-process elements is predicted to appear as an excess of rare earth elements in extremely metal-poor stars.

  11. Cosmological quantum chromodynamics, neutron diffusion, and the production of primordial heavy elements

    NASA Technical Reports Server (NTRS)

    Applegate, J. H.; Hogan, Craig J.; Scherrer, R. J.

    1988-01-01

    A simple one-dimensional model is used to describe the evolution of neutron density before and during nucleosynthesis in a high-entropy bubble left over from the cosmic quark-hadron phase transition. It is shown why cosmic nucleosynthesis in such a neutron-rich environment produces a surfeit of elements heavier than lithium. Analytical and numerical techniques are used to estimate the abundances of carbon, nitrogen, and heavier elements up to Ne-22. A high-density neutron-rich region produces enough primordial N-14 to be observed in stellar atmospheres. It shown that very heavy elements may be created in a cosmological r-process; the neutron exposure in the neutron-rich regions is large enough for the Ne-22 to trigger a catastrophic r-process runaway in which the quantity of heavy elements doubles in much less than an expansion time due to fission cycling. A primordial abundance of r-process elements is predicted to appear as an excess of rare earth elements in extremely metal-poor stars.

  12. Is there a role for fixed target heavy ion physics beyond RHIC startup?

    SciTech Connect

    Sandweiss, J.

    1995-07-15

    The interesting and important physics opportunities provided by AGS and CERN fixed target facilities will be far from exhausted by the time of RHIC turn on. Given the need for the AGS to provide heavy ion beams for injection into RHIC, the cost effectiveness of fixed target experimentation with AGS beams will be high. Examples of the physics are given.

  13. Nonlinear ion-acoustic waves in a degenerate plasma with nuclei of heavy elements

    SciTech Connect

    Hossen, M. A. Mamun, A. A.

    2015-10-15

    The ion-acoustic (IA) solitary waves propagating in a fully relativistic degenerate dense plasma (containing relativistic degenerate electron and ion fluids, and immobile nuclei of heavy elements) have been theoretically investigated. The relativistic hydrodynamic model is used to derive the Korteweg-de Vries (K-dV) equation by the reductive perturbation method. The stationary solitary wave solution of this K-dV equation is obtained to characterize the basic features of the IA solitary structures that are found to exist in such a degenerate plasma. It is found that the effects of electron dynamics, relativistic degeneracy of the plasma fluids, stationary nuclei of heavy elements, etc., significantly modify the basic properties of the IA solitary structures. The implications of this results in astrophysical compact objects like white dwarfs are briefly discussed.

  14. Altering genomic integrity: heavy metal exposure promotes trans-posable element-mediated damage

    PubMed Central

    Morales, Maria E.; Servant, Geraldine; Ade, Catherine; Roy-Enge, Astrid M.

    2015-01-01

    Maintenance of genomic integrity is critical for cellular homeostasis and survival. The active transposable elements (TEs) composed primarily of three mobile element lineages LINE-1, Alu, and SVA comprise approximately 30% of the mass of the human genome. For the past two decades, studies have shown that TEs significantly contribute to genetic instability and that TE-caused damages are associated with genetic diseases and cancer. Different environmental exposures, including several heavy metals, influence how TEs interact with its host genome increasing their negative impact. This mini-review provides some basic knowledge on TEs, their contribution to disease and an overview of the current knowledge on how heavy metals influence TE-mediated damage. PMID:25774044

  15. On the seismic age and heavy-element abundance of the Sun

    NASA Astrophysics Data System (ADS)

    Houdek, G.; Gough, D. O.

    2011-12-01

    We estimate the main-sequence age and heavy-element abundance of the Sun by means of an asteroseismic calibration of theoretical solar models using only low-degree acoustic modes from the BiSON. The method can therefore be applied also to other solar-type stars, such as those observed by the NASA satellite Kepler and the planned ground-based Danish-led Stellar Observations Network Group (SONG). The age, 4.60 ± 0.04 Gyr, obtained with this new seismic method, is similar to, although somewhat greater than, today's commonly adopted values, and the surface heavy-element abundance by mass, Zs= 0.0142 ± 0.0005, lies between the values quoted recently by Asplund et al. and by Caffau et al. We stress that our best-fitting model is not a seismic model, but a theoretically evolved model of the Sun constructed with 'standard' physics and calibrated against helioseismic data.

  16. Contamination level, distribution and health risk assessment of heavy and toxic metallic and metalloid elements in a cultivated mushroom Pleurotus florida (Mont.) singer.

    PubMed

    Khani, Rouhollah; Moudi, Maryam; Khojeh, Vahid

    2017-02-01

    There are great concentrations of toxic metallic and metalloid elements such as lead, arsenic, mercury, cadmium or silver in many species of mushrooms comparative to other fruits and vegetables. In this study, contamination with heavy and toxic metallic and metalloid elements in the cultivated mushroom of (Pleurotus florida (Mont.) Singer) is investigated. P. florida was cultivated on different substrates; wheat straw (as blank), wheat straw + pine cone, wheat straw + soybean straw and wheat straw + urea and the effects of these substrates on contamination levels of Mn, Fe, Cu, Zn, As, Cd, and Pb were analyzed. The results showed that the concentrations of essential elements (Mn, Fe, Cu, and Zn) in the target mushroom are at the typical levels. The estimated daily intakes of studied metallic and metalloid elements were below their oral reference dosage mentioned by the international regulatory bodies. Health risk index (HRI) was calculated to evaluate the consumer's health risk assessment from the metal intake that contaminated in the cultivated mushroom of P. florida on the different nutrient sources. In this study, the individual HRIs were less than 1, which indicates insignificant potential health risk associated with the consumption of target mushroom from the studied substrates. Based on the HRIs values among the toxic metallic and metalloid elements, As in the target mushroom in the substrate of the wheat straw + pine cone is the main sources of risk, and it may cause severe health problems. Thus, this study suggests that the concentrations of heavy and toxic elements should be periodically monitored in cultivated mushrooms.

  17. Long-lived heavy mass elements half-lives (A125)

    NASA Astrophysics Data System (ADS)

    Holden, N. E.

    Reported values of half-lives of intermediate mass and heavy elements are evaluated. The evaluation analysis estimates the systematic error the resulting standard deviation. Recommended values are then presented for Te-128, Te-130, I-129, La-138, Nd-144, Nd-145, Sm-146, Sm-147, Sm-148, Gd-152, Dy-154, Lu-176, Hf-174, Ta-180, Re-187, Os-186, Pt-190, Pb-204, Pb-205, and Th-230, Th-232.

  18. Fusion-Fission Dynamics of Super-Heavy Element Formation and Decay

    SciTech Connect

    Zagrebaev, V.I.

    2004-04-12

    The paper is focused on reaction dynamics of super-heavy nucleus formation and decay at beam energies near the Coulomb barrier. The aim is to review the things we have learned from recent experiments on fusion-fission reactions leading to the formation of compound nuclei with Z {>=} 102 and from their extensive theoretical analysis. Main attention is paid to the dynamics of formation of very heavy compound nuclei taking place in strong competition with the process of fast fission (quasi-fission). The choice of collective degrees of freedom playing a principal role, finding the multi-dimensional driving potential and the corresponding dynamic equation regulating the whole process are discussed. Theoretical predictions are made for synthesis of SH nuclei up to Z=120 in the asymmetric 'hot' fusion reactions basing on use of the heavy transactinide targets.

  19. Studies of Ultra-Heavy Elements in Solar Energetic Particles Above 10 MeV/nucleon

    NASA Astrophysics Data System (ADS)

    Leske, R. A.; Cohen, C. M.; Cummings, A. C.; Mewaldt, R. A.; Stone, E. C.; Wiedenbeck, M. E.; von Rosenvinge, T. T.

    2006-05-01

    Measurements below several MeV/nucleon show that abundances of elements heavier than Ni (Z=28) can be enhanced relative to oxygen by factors of ~100 to 1000 (depending on species) in impulsive solar energetic particle (SEP) events, and large gradual events are often iron-rich and may contain admixtures of flare seed material. Recently, using the Solar Isotope Spectrometer (SIS) on NASA's ACE spacecraft, which measures the composition of energetic nuclei for elements up to ~Zr (Z=40) at energies from ~10 to >100 MeV/nucleon, we have reported detection of enhanced ultra-heavy (UH) abundances in SEP events above 10 MeV/nucleon, with resolved UH elements such as Zn, Ge and Se (Z=30, 32, and 34). We present further SIS observations of ultra-heavy SEPs that can be used to test models of acceleration and abundance enhancements in both gradual and impulsive events. By surveying the entire >8 years of ACE data, we determine the average SEP composition for elements from Z=30 to 40 and examine the time distribution of these nuclei to assess whether they arrived preferentially during gradual or impulsive events. We test whether iron-rich gradual events show noticeably larger UH enhancements than other gradual events (as expected if iron-rich events contain flare seed material), and we report cases of large excesses of UH elements in impulsive events. For example, at energies >10 MeV/nucleon, the event of 23 July 2004 had a (34

  20. Assessment of essential elements and heavy metals content on Mytilus galloprovincialis from river Tagus estuary.

    PubMed

    Santos, I; Diniz, M S; Carvalho, M L; Santos, J P

    2014-06-01

    Trace elemental content was analysed in edible tissues of Mytilus galloprovincialis collected in five different sampling areas near the mouth of river Tagus estuary in Lisbon. The concentrations of essential elements (S, K, Ca, Fe, Cu, Zn, As, Br and Sr) were determined by energy-dispersive X-ray fluorescence (EDXRF) spectrometry, while toxic elements (Cr, Cd, Hg, Se and Pb) were measured by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The results show that the essential elements K and S are present at the highest concentrations in all the studied samples reaching 2,920 and 4,520 μg g(-1) (fresh weight), respectively. The highest levels of heavy metals found were in two areas close to the city for Pb and Cd, but below the maximum allowed values.

  1. NASA-SETI microwave observing project: Targeted Search Element (TSE)

    NASA Technical Reports Server (NTRS)

    Webster, L. D.

    1991-01-01

    The Targeted Search Element (TSE) performs one of two complimentary search strategies of the NASA-SETI Microwave Observing Project (MOP): the targeted search. The principle objective of the targeted search strategy is to scan the microwave window between the frequencies of one and three gigahertz for narrowband microwave emissions eminating from the direction of 773 specifically targeted stars. The scanning process is accomplished at a minimum resolution of one or two Hertz at very high sensitivity. Detectable signals will be of a continuous wave or pulsed form and may also drift in frequency. The TSE will possess extensive radio frequency interference (RFI) mitigation and verification capability as the majority of signals detected by the TSE will be of local origin. Any signal passing through RFI classification and classifiable as an extraterrestrial intelligence (ETI) candidate will be further validated at non-MOP observatories using established protocol. The targeted search will be conducted using the capability provided by the TSE. The TSE provides six Targeted Search Systems (TSS) which independently or cooperatively perform automated collection, analysis, storage, and archive of signal data. Data is collected in 10 megahertz chunks and signal processing is performed at a rate of 160 megabits per second. Signal data is obtained utilizing the largest radio telescopes available for the Targeted Search such as those at Arecibo and Nancay or at the dedicated NASA-SETI facility. This latter facility will allow continuous collection of data. The TSE also provides for TSS utilization planning, logistics, remote operation, and for off-line data analysis and permanent archive of both the Targeted Search and Sky Survey data.

  2. New Hubble Space Telescope Observations of Heavy Elements in Four Metal-Poor Stars

    NASA Astrophysics Data System (ADS)

    Roederer, Ian U.; Lawler, James E.; Sobeck, Jennifer S.; Beers, Timothy C.; Cowan, John J.; Frebel, Anna; Ivans, Inese I.; Schatz, Hendrik; Sneden, Christopher; Thompson, Ian B.

    2012-12-01

    Elements heavier than the iron group are found in nearly all halo stars. A substantial number of these elements, key to understanding neutron-capture nucleosynthesis mechanisms, can only be detected in the near-ultraviolet. We report the results of an observing campaign using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope to study the detailed heavy-element abundance patterns in four metal-poor stars. We derive abundances or upper limits from 27 absorption lines of 15 elements produced by neutron-capture reactions, including seven elements (germanium, cadmium, tellurium, lutetium, osmium, platinum, and gold) that can only be detected in the near-ultraviolet. We also examine 202 heavy-element absorption lines in ground-based optical spectra obtained with the Magellan Inamori Kyocera Echelle Spectrograph on the Magellan-Clay Telescope at Las Campanas Observatory and the High Resolution Echelle Spectrometer on the Keck I Telescope on Mauna Kea. We have detected up to 34 elements heavier than zinc. The bulk of the heavy elements in these four stars are produced by r-process nucleosynthesis. These observations affirm earlier results suggesting that the tellurium found in metal-poor halo stars with moderate amounts of r-process material scales with the rare earth and third r-process peak elements. Cadmium often follows the abundances of the neighboring elements palladium and silver. We identify several sources of systematic uncertainty that must be considered when comparing these abundances with theoretical predictions. We also present new isotope shift and hyperfine structure component patterns for Lu II and Pb I lines of astrophysical interest. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 8111 and

  3. Durability of targets and foils irradiated by intense heavy ion beams in experiments on synthesis of superheavy nuclei

    NASA Astrophysics Data System (ADS)

    Sagaidak, R. N.

    2017-09-01

    Durability of targets and window foils irradiated by intense heavy ion (HI) beams in the experiments on synthesis of superheavy nuclei, which are carried out in Dubna with Gas-Filled Recoil Separator (DGFRS), has been viewed in various ways. High fluxes of HI and heat generations, which are realized within relatively small areas and thicknesses of these elements of DGFRS, are inherent in such experiments. The lifetimes of the targets and window foils are estimated as the result of HI beam actions such as radiation damages, sputtering and evaporation of atoms. The most critical processes determining the durability of the targets and window foils are discussed. The processes of heat transfer due to thermal conductivity, convection and radiation are also considered from the point of view of possible ways of cooling of the elements irradiated by an intense HI beam. Temperatures of the targets and window foils as functions of time are calculated in the conditions of their pulse heating by the beam followed by radiative cooling of their surfaces. Such pulsing mode is realized in the DGFRS operation with the rotation of target and window foils irradiated by a continuous HI beam. Estimates show that radiative cooling in such conditions can be the most effective way of heat removal at the temperature of several hundred degrees. Such temperature can be reached on the surfaces of the target and window foils irradiated by HI beams at the intensity 1013 s-1.

  4. A transverse electron target for heavy ion storage rings

    SciTech Connect

    Geyer, Sabrina Meusel, Oliver; Kester, Oliver

    2015-01-09

    Electron-ion interaction processes are of fundamental interest for several research fields like atomic and astrophysics as well as plasma applications. To address this topic, a transverse electron target based on the crossed beam technique was designed and constructed for the application in storage rings. Using a sheet beam of free electrons in crossed beam geometry promises a good energy resolution and gives access to the interaction region for spectroscopy. The produced electron beam has a length of 10 cm in ion beam direction and a width in the transverse plane of 5 mm. Therewith, electron densities of up to 10{sup 9} electrons/cm{sup 3} are reachable in the interaction region. The target allows the adjustment of the electron beam current and energy in the region of several 10 eV to a few keV. Simulations have been performed regarding the energy resolution for electron-ion collisions and its influence on spectroscopic measurements. Also, the effect on ion-beam optics due to the space charge of the electron beam was investigated. Presently the electron target is integrated into a test bench to evaluate its performance for its dedicated installation at the storage rings of the FAIR facility. Therefore, optical diagnostics of the interaction region and charge state analysis with a magnetic spectrometer is used. Subsequently, the target will be installed temporarily at the Frankfurt Low-Energy Storage Ring (FLSR) for further test measurements.

  5. Supernova heavy element nucleosynthesis: Can it tell us about neutrino masses?

    SciTech Connect

    Fuller, George M.

    1997-05-20

    Here we describe a new probe of neutrino properties based on heavy element nucleosynthesis. This technique is in many ways akin to the familiar light element Primordial Nucleosynthesis probe of conditions in the early universe. Our new probe is based on the fact that neutrino masses and vacuum mixings can engender matter-enhanced neutrino flavor transformation in the post core bounce supernova environment. Transformations of the type {nu}{sub {mu}}{sub (r)}<-->{nu}{sub e} in this site will have significant effects on the synthesis of the rapid neutron capture (r-Process) elements and the light p-nuclei. We suggest that an understanding of the origin of these nuclides, combined with the measured abundances of these species, may provide a ''Rosetta Stone'' for neutrino properties. Heavy element nucleosynthesis abundance considerations give either constraints/evidence for neutrino masses and flavor mixings, or strong constraints on the site of origin of r-Process nucleosynthesis. The putative limits on neutrino characteristics are complimentary to those derived from laboratory neutrino oscillation studies and solar and atmospheric neutrino experiments. Preliminary studies show that the existence of r-Process nuclei in the abundances observed in the Galaxy cannot be understood unless neutrinos have small masses (possibly in the cosmologically significant range)

  6. Trace elements and heavy metals in hair of stage III breast cancer patients.

    PubMed

    Benderli Cihan, Yasemin; Sözen, Selim; Oztürk Yıldırım, Sema

    2011-12-01

    This prospective study was designed to compare the hair levels of 36 elements in 52 patients with stage III breast cancer to those of an equal number of healthy individuals. Principal component and cluster analysis were used for source of identification and apportionment of heavy metals and trace elements in these two groups. A higher average level of iron was found in samples from patients while controls had higher levels of calcium. Both patients and controls had elevated levels of tin, magnesium, zinc, and sodium. Almost all element values in cancer patients showed higher dispersion and asymmetry than in healthy controls. Between the two groups, there were statistically significant differences in the concentrations of silver, arsenic, gold, boron, barium, beryllium, calcium, cadmium, cerium, cobalt, cesium, gadolinium, manganese, nickel, lead, antimony, scandium, selenium, and zinc (p < 0.05). Strong positive correlations were found between lead and gold (r = 0.785) in the cancer group and between palladium and cobalt (r = 0.945) in the healthy individuals. Our results show that there are distinct patterns of heavy metals and trace elements in the hair of breast cancer patients in comparison to healthy controls. These results could be of significance in the diagnosis of breast cancer.

  7. The X-Target: A novel high gain target with single-sided heavy-ion beam illumination

    NASA Astrophysics Data System (ADS)

    Henestroza, Enrique

    2012-10-01

    A new inertial-fusion target configuration, the X-target, using one-sided heavy ion axial illumination has been explored [1]. It takes advantage of the unique energy deposition properties of heavy ion beams that have a classical, long penetration range. This class of target uses heavy ion beams to compress and ignite deuterium-tritium (DT) fuel that fills the interior of metal cases that have side-view cross sections in the shape of an ``X''. X-targets that incorporate inside the case a propellant (plastic) and a pusher (aluminum) surrounding the DT are capable of assembling fuel areal densities ˜2 g/cm^2 using two MJ-scale annular beams to implode quasi-spherically the target to peak DT densities ˜100 g/cm^3. A 3MJ fast-ignition solid ion beam heats the fuel to thermonuclear temperatures in ˜200 ps to start the burn propagation, obtaining gains of ˜300. The main concern for the X-target is the amount of high-Z atomic mixing at the ignition zone produced by hydro-instabilities, which, if large enough, could cool the fuel during the ignition process and prevent the propagation of the fusion burn. Analytic estimates and implosion calculations using the radiation hydrodynamics code HYDRA in 2D (RZ), at typical Eulerian mesh resolutions of a few microns, have shown that for the relatively low implosion velocities, low stagnation fuel densities, and low quasi-spherical fuel convergence ratios of the X-target, these hydro-instabilities do not have a large effect on the burning process. These preliminary studies need to be extended by further hydrodynamic calculations using finer resolution, complemented with turbulent mix modeling and validated by experiments, to ascertain the stability of the X-target design. We will present the current status of the X-target. [4pt] [1] E. Henestroza and B. G. Logan, Phys. Plasmas 19, 072706 (2012)

  8. [Levels of mineral elements composition and heavy metal pollution in human breast milk in Shenzhen City].

    PubMed

    Deng, Bo; Zhang, Huimin; Yan, Chunrong; Zhang, Lishi

    2009-05-01

    To investigate the levels of some mineral elements composition and heavy metal in human breast milk in Shenzhen, and estimate the status of infant with breast feeding. ICP-MS and ICP-AES instruments were used to detect the levels of four macroelements of Ca, K, Na, Mg and four microelements of Zn, Fe, Se, Cu, totally eight minerals as well as three heavy metal of Pb, As and Cd in human breast milk. 60 breast milk samples were collected from the women aged 20-35, lived in Shenzhen over 5 years, postdelivery 3 weeks to 2 months from Jul. to Nov. 2007. Average concentration for four kinds of macroelement of Ca, K, Na, Mg was 280.22, 498.61, 188.65 and 28.31 mg/L respectively, that for four kinds of microelements of Zn, Fe, Se, Cu was 2.29 mg/L, 358.88 microg/L, 8.28 microg/L and 339.16 microg/L respectively in 60 human breast milk samples. Average concentration of Pb was 2.13 microg/L in 60 human breest milk samples, and heavy metal As and Cd were non-detected. The nutrition status of four kinds of macroelement of Ca, K, Na, Mg and three kinds of microelements of Zn, Fe, Cu in 60 human breast milk samples were reasonable, but the lack of microelement Se and the pollution of the heavy metal should been taken into account.

  9. [Application of ICP-MS to detection of mineral elements and heavy metals in Cassava's byproducts].

    PubMed

    Tao, Hai-Teng; Zhang, Chun-Jiang; Chen, Xiao-Ming; Lüi, Fei-Jie; Tai, Jian-Xiang; Li, Kai-Mian

    2009-07-01

    Cassava is a main cultivated tropical crop in China, its rich starch roots are often used to produce fuel ethanol in recent years, so it's a kind of hot biomass energy crops. But cassava's byproducts such as leaves, stems and peels are regarded as waste, and are not fully utilized. Cassava's byproducts contain many nutrients, and can be used to process high value food products. The contents of mineral elements and heavy metals in cassava's byproducts were studied by ICP-MS. The results showed that cassava's byproducts contained many elements necessary to human health, the sequence of macroelements was K>Ca>P> Mg>S>Mn>Zn>Na>Fe>B>Cu, particularly, the contents of Fe, Mn, Zn and B ranged from 10 to 800 microg x g(-1) (DW), while the contents of microelements including Mo, Co, Se and Ge ranged from 0.01 to 0.2 microg x g(-1) (DW), which are important to human health. Besides macroelements and microelements, the contents of heavy metals (As, Cr, Pb and Hg) were also important to identify the quality of farm products, and the results showed that cassava's byproducts contained little heavy metals except Pb (2.19 microg x g(-1) (DW) in stalk peels). All the data showed that cassava's byproducts accorded with the national hygiene standards.

  10. Exploring Ultra-Heavy Cosmic Rays with the Trans-Iron Galactic Element Recorder (TIGER)

    NASA Astrophysics Data System (ADS)

    Link, Jason; Supertiger Collaboration

    2017-01-01

    Elements heavier than iron are primarily synthesized by neutron capture. These elements can be accelerated as cosmic-rays and measuring their abundances at Earth can yield information about galactic cosmic-rays' sources, the acceleration processes and the composition of the universe beyond the boundaries of our solar system. The Trans-Iron Galactic Element Recorder (TIGER) and its larger successor SuperTIGER was designed to measure the abundance of these ultra-heavy cosmic rays between Z=10 and Z=60. These detectors utilize scintillators with a wavelength shifter bar and PMT readout system as well as aerogel and acrylic Cherenkov detectors to identify the charge and energy of a particle and utilize a scintillating fiber hodoscope to provide trajectory information. In this talk I will review the results from this highly successful program, give the status for the next SuperTIGER flight planned for a December 2017 launch from Antarctica, and discuss the future direction of the program.

  11. Target Tracking in Heavy-Tailed Clutter Using Amplitude Information

    DTIC Science & Technology

    2009-07-01

    Oceanic Engineering, vol. 24, no. 3, pp. 261–284, Jul. 1999. [13] A. Papoulis and S. U. Pillai, Probability , Random Vari- ables and Stochastic...Signal to Noise Ratio (SNR) somewhere between 0dB and 20dB. This means that if the target is to be detected with a reasonably high probability one...1) Our objective is to evaluate the posterior Probability Density Function (PDF) p(xk|Zk) from the set of received measure- ments Zk = {Z1, . . . ,Zk

  12. Modeling of the distribution of heavy metals and trace elements in argan forest soil and parts of argan tree.

    PubMed

    Mohammed, Faez A E; Bchitou, Rahma; Boulmane, Mohamed; Bouhaouss, Ahmed; Guillaume, Dominique

    2013-01-01

    The transfer of heavy metals and trace elements from argan forest soil into the wood, leaves, almonds, and argan oil was studied. Analyzed metals were: chromium, cadmium, copper, zinc, lead, calcium, phosphorus, potassium, and magnesium. Correlations linking different behaviors of the studied heavy metals and trace elements observed by multidimensional analysis were attributed to partial-spatial variations. Whereas the RV-coefficient of wood, leaf, almond and oil groups was high, the soil group correlated poorly with the other groups.

  13. Ion acoustic shock waves in a degenerate relativistic plasma with nuclei of heavy elements

    NASA Astrophysics Data System (ADS)

    Atteya, A.; Behery, E. E.; El-Taibany, W. F.

    2017-03-01

    Based on the quantum hydrodynamics theory, a rigorous model for ion acoustic shock waves (IASWs) in a degenerate relativistic plasma with heavy ion nuclei is presented. Two cases are considered: the ultra-relativistic case and the non-relativistic case. A Korteweg-de Vries-Burger's (KdVB) equation describing IASWs in such plasma is derived, then its explicit as well as oscillatory solutions are deduced. It is found that the shape of IASWs is influenced by the particle density of degenerate electrons, the concentration of heavy elements, the viscosity coefficient, and the quantum Bohm potential term. The results should be useful in understanding the shock wave characteristics in degenerate plasma which is found in compact astrophysical objects.

  14. The elemental composition of the Sun. III. The heavy elements Cu to Th

    NASA Astrophysics Data System (ADS)

    Grevesse, Nicolas; Scott, Pat; Asplund, Martin; Sauval, A. Jacques

    2015-01-01

    We re-evaluate the abundances of the elements in the Sun from copper (Z = 29) to thorium (Z = 90). Our results are mostly based on neutral and singly-ionised lines in the solar spectrum. We use the latest 3D hydrodynamic solar model atmosphere, and in a few cases also correct for departures from local thermodynamic equilibrium (LTE) using non-LTE (NLTE) calculations performed in 1D. In order to minimise statistical and systematic uncertainties, we make stringent line selections, employ the highest-quality observational data and carefully assess oscillator strengths, hyperfine constants and isotopic separations available in the literature, for every line included in our analysis. Our results are typically in good agreement with the abundances in the most pristine meteorites, but there are some interesting exceptions. This analysis constitutes both a full exposition and a slight update of the relevant parts of the preliminary results we presented in Asplund et al. (2009, ARA&A, 47, 481), including full line lists and details of all input data that we have employed. Tables 1-3 are available in electronic form at http://www.aanda.org

  15. HEAVY-ELEMENT DISPERSION IN THE METAL-POOR GLOBULAR CLUSTER M92

    SciTech Connect

    Roederer, Ian U.; Sneden, Christopher

    2011-07-15

    Dispersion among the light elements is common in globular clusters (GCs), while dispersion among heavier elements is less common. We present detection of r-process dispersion relative to Fe in 19 red giants of the metal-poor GC M92. Using spectra obtained with the Hydra multi-object spectrograph on the WIYN Telescope at Kitt Peak National Observatory, we derive differential abundances for 21 species of 19 elements. The Fe-group elements, plus Y and Zr, are homogeneous at a level of 0.07-0.16 dex. The heavy-elements La, Eu, and Ho exhibit clear star-to-star dispersion spanning 0.5-0.8 dex. The abundances of these elements are correlated with one another, and we demonstrate that they were produced by r-process nucleosynthesis. This r-process dispersion is not correlated with the dispersion in C, N, or Na in M92, indicating that r-process inhomogeneities were present in the gas throughout star formation. The r-process dispersion is similar to that previously observed in the metal-poor GC M15, but its origin in M15 or M92 is unknown at present.

  16. An infrared maritime target detection algorithm applicable to heavy sea fog

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Dong, Lili; Zhao, Ming; Wu, Houde; Ji, Yuanyuan; Xu, Wenhai

    2015-07-01

    Infrared maritime images taken in heavy sea fog (HSF) are usually nonuniform in brightness distribution and targets in different region have significant differences in local contrast, which will cause great difficulty for normal target detection algorithm to remove background clutters and extract targets. To this problem, this paper proposes a new target detection algorithm based on image region division and wavelet inter-subband correlation. This algorithm will firstly divide the original image into different regions by an adaptive thresholding method OTSU. Then, wavelet threshold denoising is adopted to suppress noise in subbands. Finally, the real target is extracted according to its inter-subband correlation and local singularity in original image. Experiment results show that this algorithm can overcome the brightness nonuniformity and background clutters to extract all targets accurately. Besides, target's area is well retained. So the proposed algorithm has high practical value in maritime target search based on infrared imaging system.

  17. Forming a uniform distribution of heavy ions on a moving target

    NASA Astrophysics Data System (ADS)

    Kazarinov, N. Yu.; Kazacha, V. I.

    2017-01-01

    A way to obtain a uniform distribution of a heavy-ion beam on a moving target by scanning the beam over the target surface is considered. The scanning is performed by the horizontal and vertical scanner. A method is proposed for calculating the particle density distribution on the target with allowance for the influence of the horizontal slit in front of the target. Since the scanner forces deflecting the center of mass of the beam are periodic, the ion density distribution on the target is also a periodic function in the target motion direction and the spatial period of the function depends on the ratio of the scanner frequencies. With the high-frequency vertical scanner, a rather uniform particle density is obtained on the target despite considerable ion density inhomogeneities in the beam. With the slit, the particle density inhomogeneity on the target sharply increases when the scanned beam goes beyond the slit height.

  18. Vibrational circular dichroism spectra for large molecules and molecules with heavy elements

    NASA Astrophysics Data System (ADS)

    Reiter, Kevin; Kühn, Michael; Weigend, Florian

    2017-02-01

    We present an implementation of vibrational circular dichroism (VCD) spectra in TURBOMOLE. We mainly followed the route proposed by Cheeseman [Chem. Phys. Lett. 252, 211 (1996)] and extended the modules for calculating the magnetic response and vibrational frequencies accordingly. The implementation allows for gauge origin invariant employment of effective core potentials, as demonstrated for Co(ppy)3, ppy = 2-Phenylpyridine. In this way, scalar relativistic effects are covered and heavy elements can be treated. Further, with the present implementation molecular symmetry may be efficiently exploited, which makes the calculation of large (symmetric) systems feasible. The calculation of the VCD spectrum of icosahedral C6202+ is shown as an illustrative application.

  19. Long-lived heavy mass elements half-lives (A > 125)

    SciTech Connect

    Holden, N.E.

    1985-01-01

    Reported values of half-lives of intermediate mass and heavy elements are evaluated. The evaluation analysis estimates the systematic error the resulting standard deviation. Recommended values are then presented for /sup 128/Te, /sup 130/Te, /sup 129/I, /sup 138/La, /sup 144/Nd, /sup 145/Nd, /sup 146,147,148/Sm, /sup 152/Gd, /sup 154/Dy, /sup 176/Lu, /sup 174/Hf, /sup 180/Ta, /sup 187/Re, /sup 186/Os, /sup 190/Pt, /sup 204,205/Pb, and /sup 230,232/Th. 103 refs., 21 tabs. (WRF)

  20. Vibrational circular dichroism spectra for large molecules and molecules with heavy elements.

    PubMed

    Reiter, Kevin; Kühn, Michael; Weigend, Florian

    2017-02-07

    We present an implementation of vibrational circular dichroism (VCD) spectra in TURBOMOLE. We mainly followed the route proposed by Cheeseman [Chem. Phys. Lett. 252, 211 (1996)] and extended the modules for calculating the magnetic response and vibrational frequencies accordingly. The implementation allows for gauge origin invariant employment of effective core potentials, as demonstrated for Co(ppy)3, ppy = 2-Phenylpyridine. In this way, scalar relativistic effects are covered and heavy elements can be treated. Further, with the present implementation molecular symmetry may be efficiently exploited, which makes the calculation of large (symmetric) systems feasible. The calculation of the VCD spectrum of icosahedral C620(2+) is shown as an illustrative application.

  1. Evolution of heavy-element abundances in the Galactic halo and disk

    NASA Technical Reports Server (NTRS)

    Mathews, G. J.; Cowan, J. J.; Schramm, D. N.

    1988-01-01

    The constraints on the universal energy density and cosmological constant from cosmochronological ages and the Hubble age are reviewed. Observational evidence for the galactic chemical evolution of the heavy-element chronometers is descirbed in the context of numerical models. The viability of the recently discovered Th/Nd stellar chronometer is discussed, along with the suggestion that high r-process abundances in metal-poor stars may have resulted from a primordial r-process, as may be required by some inhomogeneous cosmologies.

  2. Controlled Synthesis of Polyions of Heavy Main-Group Elements in Ionic Liquids

    PubMed Central

    Groh, Matthias F.; Wolff, Alexander; Grasser, Matthias A.; Ruck, Michael

    2016-01-01

    Ionic liquids (ILs) have been proven to be valuable reaction media for the synthesis of inorganic materials among an abundance of other applications in different fields of chemistry. Up to now, the syntheses have remained mostly “black boxes”; and researchers have to resort to trial-and-error in order to establish a new synthetic route to a specific compound. This review comprises decisive reaction parameters and techniques for the directed synthesis of polyions of heavy main-group elements (fourth period and beyond) in ILs. Several families of compounds are presented ranging from polyhalides over carbonyl complexes and selenidostannates to homo and heteropolycations. PMID:27598123

  3. Evolution of heavy-element abundances in the Galactic halo and disk

    NASA Technical Reports Server (NTRS)

    Mathews, G. J.; Cowan, J. J.; Schramm, D. N.

    1988-01-01

    The constraints on the universal energy density and cosmological constant from cosmochronological ages and the Hubble age are reviewed. Observational evidence for the galactic chemical evolution of the heavy-element chronometers is descirbed in the context of numerical models. The viability of the recently discovered Th/Nd stellar chronometer is discussed, along with the suggestion that high r-process abundances in metal-poor stars may have resulted from a primordial r-process, as may be required by some inhomogeneous cosmologies.

  4. Thermohaline Instabilities Induced by Heavy Element Accretion onto White Dwarfs: Consequences on the Derived Accretion Rates

    NASA Astrophysics Data System (ADS)

    Deal, M.; Vauclair, S.; Vauclair, G.

    2013-01-01

    Heavy elements are observed in the atmospheres of many DA and DB white dwarfs, and their presence is attributed to the accretion of matter coming from debris disks. Several authors have deduced accretion rates from the observed abundances, taking into account the mixing induced by the convective zones and the gravitational settling. The obtained values are different for DA and DB white dwarfs. Here we show that an important process was forgotten in all these computations: thermohaline mixing, induced by the inverse μ-gradient built during the accretion process. Taking this mixing into account leads to an increase of the derived accretion rates, specially for DA white dwarfs, and modifies the conclusions.

  5. Chromatin landscape dictates HSF binding to target DNA elements.

    PubMed

    Guertin, Michael J; Lis, John T

    2010-09-09

    Sequence-specific transcription factors (TFs) are critical for specifying patterns and levels of gene expression, but target DNA elements are not sufficient to specify TF binding in vivo. In eukaryotes, the binding of a TF is in competition with a constellation of other proteins, including histones, which package DNA into nucleosomes. We used the ChIP-seq assay to examine the genome-wide distribution of Drosophila Heat Shock Factor (HSF), a TF whose binding activity is mediated by heat shock-induced trimerization. HSF binds to 464 sites after heat shock, the vast majority of which contain HSF Sequence-binding Elements (HSEs). HSF-bound sequence motifs represent only a small fraction of the total HSEs present in the genome. ModENCODE ChIP-chip datasets, generated during non-heat shock conditions, were used to show that inducibly bound HSE motifs are associated with histone acetylation, H3K4 trimethylation, RNA Polymerase II, and coactivators, compared to HSE motifs that remain HSF-free. Furthermore, directly changing the chromatin landscape, from an inactive to an active state, permits inducible HSF binding. There is a strong correlation of bound HSEs to active chromatin marks present prior to induced HSF binding, indicating that an HSE's residence in "active" chromatin is a primary determinant of whether HSF can bind following heat shock.

  6. Heavy metals and trace elements in atmospheric fall-out: their relationship with topsoil and wheat element composition.

    PubMed

    Bermudez, Gonzalo M A; Jasan, Raquel; Plá, Rita; Pignata, María L

    2012-04-30

    The objectives of this study were to determine the average concentrations and deposition rates of 28 elements in atmospheric bulk deposition and to elucidate associations among topsoil, bulk deposition and wheat element composition. The fluxes of arsenic (As), copper (Cu), lead (Pb) and zinc (Zn) deposition in Córdoba were higher than in other agro-ecosystems, which reflects both natural (geochemistry and topsoil removal) and anthropogenic sources. High lanthanide, uranium (U) and thorium (Th) concentrations revealed the impact of an open cast uranium mine. The highest enrichment factors (EF) were those of Cu, Pb, Zn and nickel (Ni), with calcium (Ca) being the most prominent in the surroundings of a cement plant. Industries and the transport of airborne urban pollutants were the main anthropogenic sources for Ca, Cu, Ni, Pb, Zn, cadmium (Cd), iron (Fe), manganese (Mn) and antimony (Sb). The concentrations of metals in wheat grain were predicted using the topsoil and atmospheric fall-out composition with R(2)=0.90, with the latter being the best explanatory variable. The present study highlights the potential health hazards of wheat consumption (Environmental Protection Agency) by the assessment of heavy metals in bulk atmospheric deposition.

  7. Data of heavy elements for light sources in EUV and XUV and for other applications

    NASA Astrophysics Data System (ADS)

    Koike, F.; Funaba, H.; Goto, M.; Kato, D.; Kato, T.; Morita, S.; Murakami, I.; Sakaue, H. A.; Sudo, S.; Suzuki, C.; Tanuma, N.; Sasaki, A.; Ding, X. B.

    2013-07-01

    Atomic ionic states and transition properties of elements with atomic numbers Z ranging from 50 to 80 are discussed as these are important to the understanding of plasmas containing such heavy elements. As such, data productions and the current status of theoretical calculations in this field are discussed. Further, recent spectroscopic measurements and respective theoretical analyses for W, Gd, and Nd are provided. The spectra of photoemissions elicited by the transitions between the sub-shell levels in N-sub-shell open atomic ions are of interest for the strong influence received from the interactions between the electronic state configurations with different constituent orbitals. Visible light emissions of W from M1 as well as E2 transitions are introduced and discussed.

  8. Abundances of secondary elements among the ultra heavy cosmic rays: Results from HEAO-3

    NASA Technical Reports Server (NTRS)

    Klarmann, J.; Margolis, S. H.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Garrard, T. L.; Israel, M. H.; Kertzman, M. P.

    1985-01-01

    Observations of the abundances of elements of charge 62 or Z or = 73 in the cosmic radiation from the HEAO-3 Heavy Nuclei Experiment (HNE) are discussed. These elements, having solar, and presumably source, abundances much less than the heavier Pt and Pb groups, are expected to be largely products of spallation. Thus they are indicators of the conditions prevailing during the propagation of cosmic rays. The abundances have changed from those reported previously due to a different data selection. This results in better charge resolution and in a higher mean energy for the particles. All the particles included were required to have had a cutoff rigidity R sub c 5 GV. This allowed the charge determination to be based solely on the Cherenkov measurement.

  9. Data of heavy elements for light sources in EUV and XUV and for other applications

    SciTech Connect

    Koike, F.; Funaba, H.; Goto, M.; Kato, D.; Kato, T.; Morita, S.; Murakami, I.; Sakaue, H. A.; Sudo, S.; Suzuki, C.; Tanuma, N.; Sasaki, A.; Ding, X. B.

    2013-07-11

    Atomic ionic states and transition properties of elements with atomic numbers Z ranging from 50 to 80 are discussed as these are important to the understanding of plasmas containing such heavy elements. As such, data productions and the current status of theoretical calculations in this field are discussed. Further, recent spectroscopic measurements and respective theoretical analyses for W, Gd, and Nd are provided. The spectra of photoemissions elicited by the transitions between the sub-shell levels in N-sub-shell open atomic ions are of interest for the strong influence received from the interactions between the electronic state configurations with different constituent orbitals. Visible light emissions of W from M1 as well as E2 transitions are introduced and discussed.

  10. Neutron Production from In-situ Heavy Ice Coated Targets at Vulcan

    NASA Astrophysics Data System (ADS)

    Morrison, John; Krygier, A. G.; Kar, S.; Ahmed, H.; Alejo, A.; Clarke, R.; Fuchs, J.; Green, A.; Jung, D.; Kleinschmidt, A.; Najmudin, Z.; Nakamura, H.; Norreys, P.; Notley, M.; Oliver, M.; Roth, M.; Vassura, L.; Zepf, M.; Borghesi, M.; Freeman, R. R.

    2015-05-01

    Laser based neutron production experiments have been performed utilizing ultra-high intensity laser accelerated ions impinging upon a secondary target. The neutron yield from such experiments may be improved if the accelerated ions were primarily deuterons taking advantage of the d-d cross section. Recent experiments have demonstrated that selective deuteron acceleration from in-situ heavy ice coating of targets can produce ion spectra where deuterons comprise > 99 % of the measured ions. Results will be presented from integrated neutron production experiments from heavy ice targets coated in-situ recently performed on the Vulcan laser at Rutherford Appleton Laboratory. We are grateful for the Staff at RAL and acknowledge funding from the US DoE. AFOSR, European Social Fund, and the Czech Republic.

  11. Recent US target-physics-related research in heavy-ion inertial fusion: target gains and constraints on accelerator design

    SciTech Connect

    Mark, J.W.K.

    1982-03-09

    Inertial-fusion targets were designed for use with heavy-ion accelerators as drivers in fusion energy power plants. In the interest of providing inputs for understanding the trade-offs among accelerator designs, an initial survey was carried out regarding target gain versus parameters of relevance. This was done in two stages, firstly target gain was related to the beam energy, power, focal radius, and ion range. Secondly, a more comprehensive discussion was made by posing target gain constraints on the beam-occupied phase-space volume of the linacs. This latter discussion had included some rather simplified models of accelerator final focus and beam transport in near-vacuum fusion reaction chambers. Some further analyses of the basic assumptions of this summary are also described.

  12. Helioseismic models of the sun with a low heavy element abundance

    NASA Astrophysics Data System (ADS)

    Ayukov, S. V.; Baturin, V. A.

    2017-10-01

    Helioseismology and neutrino experiments probing the internal structure of the Sun have yieldedmuch information, such as the adiabatic elasticity index, density, and sound speed in the convective and radiative zones, the depth of the convective zone, and the flux of neutrinos from the core. The standard model of the Sun does not adequately reproduce these characteristics, with models with low heavy element contents (mass fraction of metals Z = 0.013 in the convective zone) deviating from the helioseismic data appreciably more strongly than models with high heavy element contents ( Z = 0.018). However, a spectroscopic low Z value is supported by studies reconstructing the Γ 1 profile in the adiabatic part of the convective zone based on the oscillation frequencies. Models of the convective zone show a good agreement precisely for low Z values. This study attempts to construct a model for the Sun with low Z that satisfies the helioseismic constraints. This model requires changes in the p + p reaction cross section and the opacities in the radiative zone. In our view, the helioseismic result for the mass concentrated in the convective zone testifies that the p + p reaction cross section or the electron-screening coefficient in the solar core must be increased by several percent over the current values. This requires a comparatively small correction to the opacities (by less than 5%), in order to obtain a solar model with low Z that is in agreement with the results of helioseismology and the observed solar neutrino fluxes.

  13. AMS of heavy elements with an ECR ion source and the ATLAS linear accelerator.

    SciTech Connect

    Paul, M.; Berkovits, D.; Ahmad, I.; Borasi, F.; Caggiano, J.; Davids, C.; Greene, J.; Harss, B.; Heinz, A.; Henderson, D. J.; Henning, W.; Jiang, C. L.; Pardo, R.; Rehm, K. E.; Rejoub, R.; Seweryniak, D.; Sonzogni, A.; Uusitalo, J.; Vondrasek, R.

    1999-12-13

    Understanding the fate of heavy-metal contaminants in the environment is of fundamental importance in the development and evaluation of effective remediation and sequestration strategies. Among the factors influencing the transport of these contaminants are their chemical speciation and the chemical and physical attributes of the surrounding medium. Bacteria and the extracellular material associated with them are thought to play a key role in determining a contaminant's speciation and thus its mobility in the environment. In addition, the microenvironment at and adjacent to actively metabolizing cell surfaces can be significantly different from the bulk environment. Thus, the spatial distribution and chemical speciation of contaminants and elements that are key to biological processes must be characterized at micron and submicron resolution in order to understand the microscopic physical, geological, chemical, and biological interfaces that determine a contaminant's macroscopic fate. Hard x-ray microimaging is a powerful technique for the element-specific investigation of complex environmental samples at the needed micron and submicron resolution. An important advantage of this technique results from the large penetration depth of hard X-rays in water. This advantage minimizes the requirements for sample preparation and allows the detailed study of hydrated samples. This paper presents results of studies of the spatial distribution of naturally occurring metals and a heavy-metal contaminant (Cr) in and near hydrated bacteria (Pseudomonas fluorescens) in the early stages of biofilm development performed at the Advanced Photon Source Sector 2 X-ray microscopy beamline.

  14. Prolong Restoration of the Water Quality of River Ganga Effect of Heavy Metals and Radioactive Elements.

    PubMed

    Tare, Vinod; Basu, Subhankar

    2014-04-01

    The genesis of the present research was the belief since ages and the observations made through some studies that the water of river Ganga has unique characteristics, which allows storage of water quality even on prolong storage. Very few systematic studies have been conducted to support the contention that the Ganga water indeed has some special composition that could be attributed to its unique storage capacity. It was postulated that prolong restoration of water quality depends on the ability to arrest microbial activity that is generally responsible for deterioration in water quality on prolong storage. Hence, attempt has been made to identify the parameters that are likely to influence the prolong storage of river water. Along with Ganga river water, other three major rivers, viz. Yamuna, Godavari and Narmada, were selected for comparison. Emphasis was made on estimation of heavy metals, radioactive elements, dissolved carbon and other physicochemical parameters such as temperature, pH, alkalinity, hardness and dissolved organic carbon. Based on the available information regarding the impact of heavy metals, radioactive elements vis-à-vis the chemical composition of water on microorganisms in the aquatic environment, an overall impact score for the waters of the four Indian rivers selected in the study has been assigned.

  15. [Determination of Heavy Metal Elements in Diatomite Filter Aid by Inductively Coupled Plasma Mass Spectrometry].

    PubMed

    Nie, Xi-du; Fu, Liang

    2015-11-01

    This study established a method for determining Be, Cr, Ni, As, Cd, Sb, Sn, Tl, Hg and Pb, total 10 heavy metals in diatomite filter aid. The diatomite filter aid was digested by using the mixture acid of HNO₃ + HF+ H₃PO₄ in microwave system, 10 heavy metals elements were determined by inductively coupled plasma mass spectrometry (ICP-MS). The interferences of mass spectrometry caused by the high silicon substrate were optimized, first the equipment parameters and isotopes of test metals were selected to eliminate these interferences, the methane was selected as reactant gas, and the mass spectral interferences were eliminated by dynamic reaction cell (DRC). Li, Sc, Y, In and Bi were selected as the internal standard elements to correct the interferences caused by matrix and the drift of sensitivity. The results show that the detection limits for analyte is in the range of 3.29-15.68 ng · L⁻¹, relative standard deviations (RSD) is less than 4.62%, and the recovery is in the range of 90.71%-107.22%. The current method has some advantages such as, high sensitivity, accurate, and precision, which can be used in diatomite filter aid quality control and safety estimations.

  16. Heavy Metals and Biogenic Elements in Aquatic Systems of the Don River Delta

    NASA Astrophysics Data System (ADS)

    Tkachenko, Anna; Tkachenko, Oleg

    2014-05-01

    River deltas are located in the lower parts of the cascade landscape-geochemical systems of the river basins, so their geochemical conditions often characterize the anthropogenic impact on whole river system. The Don River runs through the one of the most agriculturally developed and densely populated area of Russia, and flows into the Azov Sea - the smallest and shallowest sea in the world. These factors determine the geochemical features of aquatic systems of the Don River mouth area and the specificity of the "river-sea" geochemical barrier zone. The paper presents results of the field studies of the geochemical structure of the Don River mouth area, which were conducted in frames of the RFBR project in 2012-2013. Major types of the deltaic water streams and bodies were studied in different hydrological seasons: spring floods, summer, autumn and winter low water periods. About 50 samples of water, suspended matter and 60 samples of bottom sediments have been collected and analyzed for heavy metals (Fe, Mn, Zn, Cu, Ni, Co, Pb, Cr, Cd etc.) and biogenic elements (nitrate, nitrite, ammonium, phosphates, silica, total nitrogen and phosphorus, dissolved oxygen and chlorophyll) content. To assess the toxicity degree and nutrient potential of water, bioassay test conducted by growing daphnia in water samples were held. The study shows that the Don River delta water is characterized by the relatively low values of dissolved heavy metal content. Significantly higher values of heavy metals were determined in the vicinity of settlements only. Metal accumulation in bottom sediments can be associated mainly with the rate of water flow. Higher values were found in sediments of small channels with weak flow velocity and prevailing processes of the suspended matter deposition. The data on the seasonal dynamics of nutrients and spatial variability of their forms have been obtained. The maximum concentration of nitrogen, phosphorus, silicon, and other biogenic elements are

  17. An Induction Linac Driver For A 0.44 MJ Heavy-Ion Direct Drive Target

    SciTech Connect

    Seidl, P.A.; Lee, E.P.; Bangerter, R.O.; Faltens, A.

    2010-02-08

    The conceptual design of a heavy ion fusion driver system is described, including all major components. Particular issues emerging from this exercise are identified and discussed. The most important conclusion of our study is that due to stringent requirements on ion pulse phase space, we are unable to find a credible accelerator design that meets the requirements of the example target. Either the target design must be modified to accept larger ion ranges and larger focal spot sizes, or we must consider other target options.

  18. Directions for reactor target design based on the US heavy ion fusion systems assessment

    SciTech Connect

    Wilson, D.C.; Dudziak, D.; Magelssen, G.; Zuckerman, D.; Dreimeyer, D.

    1986-01-01

    We studied areas of major uncertainty in target design using the cost of electricity as our figure of merit. Net electric power from the plant was fixed at 1000 MW to eliminate large effects due to economies of scale. The system is relatively insensitive to target gain. Factors of three changes in gain cause only 8 to 12% changes in electricity cost. An increase in the peak power needed to drive targets poses only a small cost risk, but requires many more beamlets be transported to the target. A shortening of the required ion range causes both cost and beamlet difficulties. A factor of 4 decrease in the required range at a fixed driver energy increases electricity cost by 44% and raises the number of beamlets to 240. Finally, the heavy ion fusion system can accommodate large increases in target costs. To address the major uncertainties, target design should concentrate on the understanding requirements for ion range and peak driver power.

  19. Heavy element accumulation in Evernia prunastri lichen transplants around a municipal solid waste landfill in central Italy.

    PubMed

    Nannoni, Francesco; Santolini, Riccardo; Protano, Giuseppe

    2015-09-01

    This paper presents the results of a biomonitoring study to evaluate the environmental impact of airborne emissions from a municipal solid waste landfill in central Italy. Concentrations of 11 heavy elements, as well as photosynthetic efficiency and cell membrane integrity were measured in Evernia prunastri lichens transplanted for 4months in 17 monitoring sites around the waste landfill. Heavy element contents were also determined in surface soils. Analytical data indicated that emissions from the landfill affected Cd, Co, Cr, Cu, Ni, Pb, Sb and Zn concentrations in lichens transplanted within the landfill and along the fallout direction. In these sites moderate to severe accumulation of these heavy elements in lichens was coupled with an increase in cell membrane damage and decrease in photosynthetic efficiency. Nevertheless, results indicated that landfill emissions had no relevant impact on lichens, as heavy element accumulation and weak stress symptoms were detected only in lichen transplants from sites close to solid waste. The appropriate management of this landfill poses a low risk of environmental contamination by heavy elements. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. [Determination of trace heavy metal elements in cortex Phellodendron chinense by ICP-MS after microwave-assisted digestion].

    PubMed

    Kou, Xing-Ming; Xu, Min; Gu, Yong-Zuo

    2007-06-01

    An inductively coupled plasma mass spectrometry (ICP-MS) for determination of the contents of 8 trace heavy metal elements in cortex Phellodendron chinense after microwave-assisted digestion of the sample has been developed. The accuracy of the method was evaluated by the analysis of corresponding trace heavy metal elements in standard reference materials (GBW 07604 and GBW 07605). By applying the proposed method, the contents of 8 trace heavy metal elements in cortex Phellodendron chinense cultivated in different areas (in Bazhong, Yibin and Yingjing, respectively) of Sichuan and different growth period (6, 8 and 10 years of samples from Yingjing) were determined. The relative standard deviation (RSD) is in the range of 3.2%-17.8% and the recoveries of standard addition are in the range of 70%-120%. The results of the study indicate that the proposed method has the advantages of simplicity, speediness and sensitivity. It is suitable for the determination of the contents of 8 trace heavy metal elements in cortex Phellodendron chinense. The results also show that the concentrations of 4 harmful trace heavy metal elements As, Cd, Hg and Pb in cortex Phellodendron chinense are all lower than the limits of Chinese Pharmacopoeia and Green Trade Standard for Importing and Exporting Medicinal Plant and Preparation. Therefore, the cortex Phellodendron chinense is fit for use as medicine and export.

  1. Levels and spatial distribution of airborne chemical elements in a heavy industrial area located in the north of Spain.

    PubMed

    Lage, J; Almeida, S M; Reis, M A; Chaves, P C; Ribeiro, T; Garcia, S; Faria, J P; Fernández, B G; Wolterbeek, H T

    2014-01-01

    The adverse health effects of airborne particles have been subjected to intense investigation in recent years; however, more studies on the chemical characterization of particles from pollution emissions are needed to (1) identify emission sources, (2) better understand the relative toxicity of particles, and (3) pinpoint more targeted emission control strategies and regulations. The main objective of this study was to assess the levels and spatial distribution of airborne chemical elements in a heavy industrial area located in the north of Spain. Instrumental and biomonitoring techniques were integrated and analytical methods for k0 instrumental neutron activation analysis and particle-induced x-ray emission were used to determine element content in aerosol filters and lichens. Results indicated that in general local industry contributed to the emissions of As, Sb, Cu, V, and Ni, which are associated with combustion processes. In addition, the steelwork emitted significant quantities of Fe and Mn and the cement factory was associated with Ca emissions. The spatial distribution of Zn and Al also indicated an important contribution of two industries located outside the studied area.

  2. Possible Way To Describe Breit's Interaction in Solids Composed From Heavy Elements

    SciTech Connect

    Kutepov, A L

    2009-02-24

    The report describes a theoretical procedure which could help evaluate the effect of quantum electrodynamic corrections on the electronic structure of crystals consisting of heavy elements. The procedure uses the effective Breit interaction as correction to traditional Coulomb interaction between electrons in non-relativistic theory. A number of other simplifying assumptions were made since even such a simplified consideration of quantum electrodynamic effects in crystals is a great challenge. These are as follows: (1) Exchange and correlation effects from the nonrelativistic interaction (the Coulomb term) between electrons are described within Density Functional Theory (DFT). (2) The Breit correction is on at the phase which involves the calculation of matrix elements between basis functions which define the single-electron spectrum of a crystal. In order to calculate the contribution from the Breit correction, the total wave function of electrons in the crystal is approximated by one Slater determinant consisting of the single-electron DFT-orbitals. (3) Only local matrix elements (i.e., the part of the two-electron integral for which both coordinate arguments belong to one and the same muffin-tin sphere) are considered.

  3. Heavy metals and other elements in serum of cattle from organic and conventional farms.

    PubMed

    Tomza-Marciniak, Agnieszka; Pilarczyk, Bogumiła; Bąkowska, Małgorzata; Pilarczyk, Renata; Wójcik, Jerzy

    2011-11-01

    Concentrations of cadmium, lead, iron, zinc, copper, chromium, nickel, aluminium and arsenium were analysed in blood serum of cattle from organic (n=20) and conventional (n=21) farms. The elements were determined by inductively coupled plasma atomic emission spectrometry using an Optima 2000 DV instrument (Perkin Elmer Inc.). Animals from the organic farm were characterised by significantly lower (P<0.01) serum concentrations of Pb, Zn, Fe, Cu, Cr, Ni, As and Al compared to animals from the conventional farm. The concentration of Cd was similar in animals from both organic and conventional farms. The concentration of toxic elements in cattle from organic and conventional farms studied was very low. The trace essential elements were generally within the adequate ranges except Zn and Cu, which were deficient. In organically reared animals, also serum Fe content was below the critical level for diagnosing iron deficiency. Pb was significantly correlated with Cd, Zn, Fe, Cu and Ni. A significant positive correlation between the concentration of Cd and Zn, Cu and Ni concentrations was only observed in cows from the organic farm. The present results suggest that organically raised animals are less exposed to harmful environmental influences such as the environmental pollution with heavy metals. On the other hand, these animals are at a greater risk of mineral deficiency compared to animals kept on conventional farms.

  4. Heavy metal and other trace elements in native mussel Diplodon chilensis from Northern Patagonia Lakes, Argentina.

    PubMed

    Guevara, S Ribeiro; Bubach, D; Vigliano, P; Lippolt, G; Arribére, M

    2004-01-01

    Native mussels, Diplodon chilensis, were sampled from four lakes in Nahuel Huapi National Park, Northern Patagonia, Argentina in order to evaluate heavy-metal distribution in the region and to assess the contribution of this compartment of the trophic web to their circulation in the food chain. The concentration of potential pollutants Ag, As, Cr, Hg, Sb, and Se, and other nine elements of interest (Ba, Br, Ca, Co, Cs, Fe, Na, Sr, and Zn) were determined in Diplodon chilensis pooled samples. Digestive glands were analyzed separately from soft tissues. Geological tracers Sc, Ta, Th, and rare earth elements were also determined in order to discriminate lithophile contributions. Elemental concentrations of Ba, Br, Fe, Sr, Se, and Zn in total soft tissues samples do not show significant differences among sampling sites. Arsenic and Cr contents in total soft tissues and digestive gland pooled samples are higher in sampling points close to zones with human settlements. Silver contents in samples collected in Lake Nahuel Huapi were higher than in the other lakes studied, and up to 50-fold higher than the sample collected in Lake Traful, considered as the reference. Mercury highest concentration values measured in total soft tissues pooled samples from lakes Nahuel Huapi and Moreno were found to be similar to those observed in other reported Hg contamination situations, and they are three to five times higher than those of the reference samples collected in Lake Traful.

  5. Effects of elemental sulphur on heavy metal uptake by plants growing on municipal sewage sludge.

    PubMed

    Dede, Gulgun; Ozdemir, Saim

    2016-01-15

    In this study experiment was carried out to determine the phytoextraction potential of six plant species (Conium maculatum, Brassica oleraceae var. oleraceae, Brassica juncea, Datura stramonium, Pelargonium hortorum and Conyza canadensis) grown in a sewage sludge medium amended with metal uptake promoters. The solubility of Cu, Cd and Pb was significantly increased with the application of elemental S due to decrease of pH. Faecal coliform number was markedly decreased by addition of elemental sulphur. The extraction of Cu, Cr and Pb from sewage sludge by using B. juncea plant was observed as 65%, 65% and 54% respectively that is statistically similar to EDTA as sulphur. The bioaccumulation factors were found higher (>1) in the plants tested for Cu and Pb like B. juncea. Translocation index (TI) calculated values for Cd and Pb were greater than one (>1) in both C. maculatum and B. oleraceae var. oleraceae. The results cleared that the amendment of sludge with elemental sulphur showed potential to solubilize heavy metals in phytoremediation as much as EDTA.

  6. Infrared small target detection in heavy sky scene clutter based on sparse representation

    NASA Astrophysics Data System (ADS)

    Liu, Depeng; Li, Zhengzhou; Liu, Bing; Chen, Wenhao; Liu, Tianmei; Cao, Lei

    2017-09-01

    A novel infrared small target detection method based on sky clutter and target sparse representation is proposed in this paper to cope with the representing uncertainty of clutter and target. The sky scene background clutter is described by fractal random field, and it is perceived and eliminated via the sparse representation on fractal background over-complete dictionary (FBOD). The infrared small target signal is simulated by generalized Gaussian intensity model, and it is expressed by the generalized Gaussian target over-complete dictionary (GGTOD), which could describe small target more efficiently than traditional structured dictionaries. Infrared image is decomposed on the union of FBOD and GGTOD, and the sparse representation energy that target signal and background clutter decomposed on GGTOD differ so distinctly that it is adopted to distinguish target from clutter. Some experiments are induced and the experimental results show that the proposed approach could improve the small target detection performance especially under heavy clutter for background clutter could be efficiently perceived and suppressed by FBOD and the changing target could also be represented accurately by GGTOD.

  7. Light and heavy element isotopic compositions of mainstream SiC grains.

    SciTech Connect

    Amari, S.; Clayton, R. N.; Davis, A. M.; Lewis, R. S.; Pellin, M. J.

    1999-02-03

    Although a variety of types of pre-solar SiC grains have been classified by their C, N, and Si isotopic composition, the majority of such grains are so-called mainstream grains and are believed to have come from asymptotic giant branch stars [1]. We have previously reported the Mo isotopic compositions of presolar SiC grains whose C, N, and Si isotopic compositions were not known [2]. Since most presolar SiC grains fall in the mainstream group, we assumed that these grains were mainstream. The excellent match of the Mo isotopic data with expectations for nucleosynthesis in AGB stars was consistent with this identification. In order to better understand the distribution of isotopic compositions in presolar grains, we have begun to measure heavy element isotopic compositions of presolar SiC grains of known C, N and Si isotopic composition.

  8. Interannual heavy element and nutrient concentration trends in the top sediments of Venice Lagoon (Italy).

    PubMed

    Masiol, Mauro; Facca, Chiara; Visin, Flavia; Sfriso, Adriano; Pavoni, Bruno

    2014-12-15

    The elemental composition of surficial sediments of Venice Lagoon (Italy) in 1987, 1993, 1998 and 2003 were investigated. Zn and Cr concentrations resulted in higher than background levels, but only Cd and Hg were higher than legal quality standards (Italian Decree 2010/260 and Water Framework Directive 2000/60/EC). Contaminants with similar spatial distribution are sorted into three groups by means of correlation analysis: (i) As, Co, Cd, Cu, Fe, Pb, Zn; (ii) Ni, Cr; (iii) Hg. Interannual concentrations are compared by applying a factor analysis to the matrix of differences between subsequent samplings. A general decrease of heavy metal levels is observed from 1987 to 1993, whereas particularly high concentrations of Ni and Cr are recorded in 1998 as a consequence of intense clam fishing, subsequently mitigated by better prevention of illegal harvesting. Due to the major role played by anthropogenic sediment resuspension, bathymetric variations are also considered. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Models of H II regions - Heavy element opacity, variation of temperature

    NASA Technical Reports Server (NTRS)

    Rubin, R. H.

    1985-01-01

    A detailed set of H II region models that use the same physics and self-consistent input have been computed and are used to examine where in parameter space the effects of heavy element opacity is important. The models are briefly described, and tabular data for the input parameters and resulting properties of the models are presented. It is found that the opacities of C, Ne, O, and to a lesser extent N play a vital role over a large region of parameter space, while S and Ar opacities are negligible. The variation of the average electron temperature T(e) of the models with metal abundance, density, and T(eff) is investigated. It is concluded that by far the most important determinator of T(e) is metal abundance; an almost 7000 K difference is expected over the factor of 10 change from up to down abundances.

  10. Models of H II regions - Heavy element opacity, variation of temperature

    NASA Technical Reports Server (NTRS)

    Rubin, R. H.

    1985-01-01

    A detailed set of H II region models that use the same physics and self-consistent input have been computed and are used to examine where in parameter space the effects of heavy element opacity is important. The models are briefly described, and tabular data for the input parameters and resulting properties of the models are presented. It is found that the opacities of C, Ne, O, and to a lesser extent N play a vital role over a large region of parameter space, while S and Ar opacities are negligible. The variation of the average electron temperature T(e) of the models with metal abundance, density, and T(eff) is investigated. It is concluded that by far the most important determinator of T(e) is metal abundance; an almost 7000 K difference is expected over the factor of 10 change from up to down abundances.

  11. Dimers of heavy p-elements of groups IV-VI: Electronic, vibrational, and magnetic properties

    NASA Astrophysics Data System (ADS)

    Borisova, S. D.; Rusina, G. G.; Eremeev, S. V.; Chulkov, E. V.

    2016-04-01

    Equilibrium lengths and binding energies, vibrational frequencies, width of the HOMO-LUMO gap, and the magnetic anisotropy energies for one- and two-component dimers of heavy p elements of Groups IV (Sn, Pb), V (Sb, Bi), and VI (Se, Te) with a pronounced relativistic effect have been calculated with the use of the formalism of the density functional theory. It has been shown that it is necessary to take into account the spin-orbit coupling, which significantly affects the energy parameters of clusters. The analysis of the data obtained has revealed that the Pb-Te, Pb-Se, Sn-Te, and Sn-Se dimers have the widest gap at the Fermi level and the lowest reactivity. The magnetic anisotropy energy has been calculated for all single- and doublecomponent dimers and the direction of the easy magnetization axis has been determined.

  12. Lead, platinum and other heavy elements in the primary cosmic radiation: HEAO-3 results

    NASA Technical Reports Server (NTRS)

    Waddington, C. J.; Binns, W. R.; Brewster, N. R.; Fixsen, D. J.; Garrard, T. L.; Israel, M. H.; Klarmann, J.; Newport, B. J.; Stone, E. C.

    1986-01-01

    An observation of the abundances of cosmic-ray lead and platinum-group nuclei using data from the HEAO-3 Heavy Nuclei Experiment (HNE) which consisted of ion chambers mounted on both sides of a plastic Cherenkov counter (Binns et al., 1981) is reported. Further analysis with more stringent selections, inclusion of additional data, and a calibration at the LBL Bevalac, have allowed the determination of the abundance ratio of lead and the platinum group of elements for particles that had a cutoff rigidity R(c) 5 GV. The observed ratio for Pb/Pt is distinctly lower than that predicted by any of the standard models for cosmic ray sources. It is possible that the difference is not an indication that the cosmic ray source composition is greatly different from that of the solar system, but rather that there is less Pb in the solar system and in the r-process than is assumed in the standard models.

  13. Safety analysis report for the Heavy-Element Facility (Building 251), Lawrence Livermore National Laboratory

    SciTech Connect

    Kvam, D.J.

    1982-10-11

    A comprehensive safety analysis was performed on the Lawrence Livermore National Laboratory's Heavy Element Facility, Building 251. The purpose of the analysis was to evaluate the building and its operations in order to inform LLNL and the Department of Energy of the risks they assume at Building 251. This was done by examining all of the energy sources and matching them with the physical and administrative barriers that control, prevent, or mitigate their hazards. Risk was evaluated for each source under both normal and catastrophic circumstances such as fire, flood, high wind, lighting, earthquake, and criticality. No significant safety deficiencies were found; it is concluded that the operation of the facility presents no unacceptable risk.

  14. Heavy elements in globular clusters: The role of asymptotic giant branch stars

    SciTech Connect

    Straniero, O.; Cristallo, S.; Piersanti, L.

    2014-04-10

    Recent observations of heavy elements in globular clusters reveal intriguing deviations from the standard paradigm of the early galactic nucleosynthesis. If the r-process contamination is a common feature of halo stars, s-process enhancements are found in a few globular clusters only. We show that the combined pollution of asymptotic giant branch (AGB) stars with a mass ranging between 3 to 6 M {sub ☉} may account for most of the features of the s-process overabundance in M4 and M22. In these stars, the s process is a mixture of two very different neutron-capture nucleosynthesis episodes. The first is due to the {sup 13}C(α, n){sup 16}O reaction and takes place during the interpulse periods. The second is due to the {sup 22}Ne(α, n){sup 25}Mg reaction and takes place in the convective zones generated by thermal pulses. The production of the heaviest s elements (from Ba to Pb) requires the first neutron burst, while the second produces large overabundances of light s (Rb, Sr, Y, Zr). The first mainly operates in the less massive AGB stars, while the second dominates in the more massive. From the heavy-s/light-s ratio, we derive that the pollution phase should last for 150 ± 50 Myr, a period short enough compared to the formation timescale of the globular cluster system, but long enough to explain why the s-process pollution is observed in a few cases only. With few exceptions, our theoretical prediction provides a reasonable reproduction of the observed s-process abundances, from Sr to Hf. However, Ce is probably underproduced by our models, while Rb and Pb are overproduced. Possible solutions are discussed.

  15. HAT-P-26b: A Neptune-mass Exoplanet with Primordial Solar Heavy Element Abundance

    NASA Astrophysics Data System (ADS)

    Wakeford, Hannah; Sing, David; Deming, Drake; Kataria, Tiffany; Lopez, Eric

    2016-10-01

    A trend in giant planet mass and atmospheric heavy elemental abundance was first noted last century from observations of planets in our own solar system. These four data points from Jupiter, Saturn, Uranus, and Neptune have served as a corner stone of planet formation theory. Here we add another point in the mass-metallicity trend from a detailed observational study of the extrasolar planet HAT-P-26b, which inhabits the critical mass regime near Neptune and Uranus. Neptune-sized worlds are among the most common planets in our galaxy and frequently exist in orbital periods very different from that of our own solar system ice giants. Atmospheric studies are the principal window into these worlds, and thereby into their formation and evolution, beyond those of our own solar system. Using the Hubble Space Telescope and Spitzer, from the optical to the infrared, we conducted a detailed atmospheric study of the Neptune-mass exoplanet HAT-P-26b over 0.5 to 4.5 μm. We detect prominent H2O absorption at 1.4 μm to 525 ppm in the atmospheric transmission spectrum. We determine that HAT-P-26b's atmosphere is not rich in heavy elements (≈1.8×solar), which goes distinctly against the solar system mass-metallicity trend. This likely indicates that HAT-P-26b's atmosphere is primordial and obtained its gaseous envelope late in its disk lifetime with little contamination from metal-rich planetesimals.

  16. HAT-P-26b: A Neptune-mass Exoplanet with Primordial Solar Heavy Element Abundance

    NASA Astrophysics Data System (ADS)

    Wakeford, Hannah R.; Sing, David K.; Kataria, Tiffany; Deming, Drake; Nikolov, Nikolay; Lopez, Eric; Tremblin, Pascal; Skalid Amundsen, David; Lewis, Nikole K.; Mandell, Avi; Fortney, Jonathan J.; Knutson, Heather; Benneke, Björn; Evans, Tom M.

    2017-01-01

    A trend in giant planet mass and atmospheric heavy elemental abundance was first noted last century from observations of planets in our own solar system. These four data points from Jupiter, Saturn, Uranus, and Neptune have served as a corner stone of planet formation theory. Here we add another point in the mass-metallicity trend from a detailed observational study of the extrasolar planet HAT-P-26b, which inhabits the critical mass regime near Neptune and Uranus. Neptune-sized worlds are among the most common planets in our galaxy and frequently exist in orbital periods very different from that of our own solar system ice giants. Atmospheric studies are the principal window into these worlds, and thereby into their formation and evolution, beyond those of our own solar system. Using the Hubble Space Telescope and Spitzer, from the optical to the infrared, we conducted a detailed atmospheric study of the Neptune-mass exoplanet HAT-P-26b over 0.5 to 4.5 μm. We detect prominent H2O absorption at 1.4 μm to 525 ppm in the atmospheric transmission spectrum. We determine that HAT-P-26b’s atmosphere is not rich in heavy elements (≈1.8×solar), which goes distinctly against the solar system mass-metallicity trend. This likely indicates that HAT-P-26b’s atmosphere is primordial and obtained its gaseous envelope late in its disk lifetime with little contamination from metal-rich planetesimals.

  17. Size of lethality target in mouse immature oocytes determined with accelerated heavy ions.

    PubMed

    Straume, T; Dobson, R L; Kwan, T C

    1989-01-01

    Mouse immature oocytes were irradiated in vivo with highly charged, heavy ions from the Bevalac accelerator at the Lawrence Berkeley Laboratory. The particles used were 670-MeV/nucleon Si14+, 570-MeV/nucleon Ar18+, and 450-MeV/nucleon Fe26+. The cross-sectional area of the lethality target in these extremely radiosensitive cells was determined from fluence-response curves and information on energy deposition by delta rays. Results indicate a target cross-section larger than that of the nucleus, one which closely approximates the cross-sectional area of the entire oocyte. For 450-MeV/nucleon Fe26+ particles, the predicted target cross-sectional area is 120 +/- 16 microns2, comparing well with the microscopically determined cross-sectional area of 111 +/- 12 microns2 for these cells. The present results are in agreement with our previous target studies which implicate the oocyte plasma membrane.

  18. Interactions of heavy nuclei, Kr, Xe and Ho, in light targets

    NASA Technical Reports Server (NTRS)

    Kertzman, M. P.; Klarmann, J.; Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Garrard, T. L.; Israel, M. H.

    1985-01-01

    Over the past few years, the HEAO-3 measurements of the abundances of ultra-heavy cosmic ray nuclei (Z 26) at earth have been analyzed. In order to interpret these abundances in terms of a source composition, allowance must be made for the propagation of the nuclei in the interstellar medium. Vital to any calculation of the propagation is a knowlege of the total and partial interaction cross sections for these heavy nuclei on hydrogen. Until recently, data on such reactions have been scarce. However, now that relativistic heavy ion beams are available at the LBL Bevalac, some of the cross sections of interest can be measured at energies close to those of the cosmic ray nuclei being observed. During a recent calibration at the Bevalac of an array similar to the HEAO-C3 UH-nuclei detector, targets of raphite (C), polyethylene (CH2), and aluminum were exposed to five heavy ion beams ranging in charge (Z) from 36 to 92. Total and partial charge changing cross sections for the various beam nuclei on hydrogen can be determined from the measured cross sections on C and CH2, and will be applied to the propagation problem. The cross sections on Al can be used to correct the abundances of UH cosmic rays observed in the HEAO C-3 detector for interactions in the detector itself.

  19. Spatial and foveal biases, not perceived mass or heaviness, explain the effect of target size on representational momentum and representational gravity.

    PubMed

    De Sá Teixeira, Nuno; Oliveira, Armando Mónica

    2014-11-01

    The spatial memory for the last position occupied by a moving target is usually displaced forward in the direction of motion. Interpreted as a mental analogue of physical momentum, this phenomenon was coined representational momentum (RM). As momentum is given by the product of an object's velocity and mass, both these factors came to be under scrutiny in RM studies, the goal being to provide support for the internalization hypothesis. Although velocity was found to determine RM's magnitude, possible effects of mass were more elusive. Recently, an effect of target size on RM was reported, adding to previous findings that bigger targets were more mislocalized downward in the direction of gravity (via perceived heaviness and representational gravity; RG). The aim in the present research was to test that those outcomes reflect an internalization of momentum by excluding oculomotor factors. The results showed that an effect of target size, when it emerged, could be accounted for by a foveal bias such that bigger targets were more displaced toward gaze than were smaller ones. Specific contingencies between eye movements and target size seem to account for previous reports regarding the alleged effects of perceived mass on both RM and RG. This phenomenon seems furthermore to be modulated by the presence of other visual elements (fixation point) and the range of target velocities. These outcomes are taken as a rebuttal to the claim that cognitive analogues of mass or heaviness are responsible for previously reported effects of target size on both RM and RG.

  20. Naturally occurring heavy radioactive elements in the geothermal microcosm of the Los Azufres (Mexico) volcanic complex.

    PubMed

    Abuhani, W A; Dasgupta-Schubert, N; Villaseñor, L M; García Avila, D; Suárez, L; Johnston, C; Borjas, S E; Alexander, S A; Landsberger, S; Suárez, M C

    2015-01-01

    The Los Azufres geothermal complex of central Mexico is characterized by fumaroles and boiling hot-springs. The fumaroles form habitats for extremophilic mosses and ferns. Physico-chemical measurements of two relatively pristine fumarolic microcosms point to their resemblance with the paleo-environment of earth during the Ordovician and Devonian periods. These geothermal habitats were analysed for the distribution of elemental mass fractions in the rhizospheric soil (RS), the native volcanic substrate (VS) and the sediments (S), using the new high-sensitivity technique of polarized x-ray energy dispersive fluorescence spectrometry (PEDXRF) as well as instrumental neutron activation analysis (INAA) for selected elements. This work presents the results for the naturally occurring heavy radioactive elements (NOHRE) Bi, Th and U but principally the latter two. For the RS, the density was found to be the least and the total organic matter content the most. Bi was found to be negligibly present in all substrate types. The average Th and U mass fractions in the RS were higher than in the VS and about equal to their average mass fractions in the S. The VS mass fraction of Th was higher, and of U lower, than the mass fractions in the earth's crust. In fact for the fumaroles of one site, the average RS mass fractions of these elements were higher than the averaged values for S (without considering the statistical dispersion). The immobilization of the NOHRE in the RS is brought about by the bio-geochemical processes specific to these extremophiles. Its effectiveness is such that despite the small masses of these plants, it compares with, or may sometimes exceed, the immobilization of the NOHRE in the S by the abiotic and aggressive chemical action of the hot-springs. These results indicate that the fumarolic plants are able to transform the volcanic substrate to soil and to affect the NOHRE mass fractions even though these elements are not plant nutrients. Mirrored back to

  1. SRNL Development of Recovery Processes for Mark-18A Heavy Actinide Targets

    SciTech Connect

    Allender, Jeffrey S.; Bridges, Nicholas J.; Loftin, Bradley M.; Dunsmuir, Michael D.

    2015-07-14

    Savannah River National Laboratory (SRNL) and Oak Ridge National Laboratory (ORNL) are developing plans for the recovery of rare and unique isotopes contained within heavy-actinide target assemblies, specifically the Mark-18A. Mark-18A assemblies were irradiated in Savannah River Site (SRS) reactors in the 1970s under extremely high neutron-flux conditions and produced, virtually, the world's supply of plutonium-244, an isotope of key importance to high-precision actinide measurement and other scientific and nonproliferation uses; and curium highly enriched in heavy isotopes (e.g., curium-246 and curium-248). In 2015 and 2016, SRNL is pursuing tasks that would reduce program risk and budget requirements, including further characterization of unprocessed targets; engineering studies for the use of the SRNL Shielded Cells Facility (SCF) for recovery; and development of onsite and offsite shipping methods including a replacement for the heavy (70 ton) cask previously used for onsite transfer of irradiated items at SRS. A status update is provided for the characterization, including modeling using the Monte Carlo N-Particle Transport Code (MCNP); direct non-destructive assay measurements; and cask design.

  2. Enhancement of X-ray Energy Deposition via Heavy Element Sensitization in Biological Environments

    NASA Astrophysics Data System (ADS)

    Lim, Sara; Pradhan, Anil; Nahar, Sultana; Barth, Rolf

    2015-05-01

    Energy (dose) deposition by low vs. high energy x-rays (LEX & HEX), approximately E ~ 100 keV and E > 1 MeV respectively, was studied in biological matter sensitized with heavy elements (high-Z or HZ) to improve radiation therapy of cancer. Computations and simulations show that LEX interact favorably with HZ sensitizers by depositing more dose than HEX. LEX photons effectively photoionize deep inner electronic shells and release cell-killing Auger electrons near malignant cells embedded with HZ atoms. HEX photons predominantly Compton scatter with little interaction, even with HZ elements. Monte Carlo simulations show that in comparison to unsensitized tissue, LEX irradiation of HZ-sensitized models resulted in up to a factor of 2 increase in dose deposition relative to HEX. To validate the studies, in vitro experiments were performed using 2 distinct cancer cell types treated with Pt-based sensitizers, then irradiated with a LEX 160 KV x-ray source and a HEX 6 MV LINAC employed in radiation therapy. The experiments support numerical simulations, and demonstrate several factors lower survival of HZ-sensitized cells irradiated with LEX compared with HEX.

  3. VizieR Online Data Catalog: Compilation of atomic data for key heavy elements (Cashman+, 2017)

    NASA Astrophysics Data System (ADS)

    Cashman, F. H.; Kulkarni, V. P.; Kisielius, R.; Ferland, G. J.; Bogdanovich, P.

    2017-06-01

    Measurements of element abundances in galaxies from astrophysical spectroscopy depend sensitively on the atomic data used. With the goal of making the latest atomic data accessible to the community, we present a compilation of selected atomic data for resonant absorption lines at wavelengths longward of 911.753Å (the HI Lyman limit), for key heavy elements (heavier than atomic number 5) of astrophysical interest. In particular, we focus on the transitions of those ions that have been observed in the Milky Way interstellar medium (ISM), the circumgalactic medium (CGM) of the Milky Way and/or other galaxies, and the intergalactic medium (IGM). We provide wavelengths, oscillator strengths, associated accuracy grades, and references to the oscillator strength determinations. We also attempt to compare and assess the recent oscillator strength determinations. For about 22% of the lines that have updated oscillator strength values, the differences between the former values and the updated ones are >~0.1dex. Our compilation will be a useful resource for absorption line studies of the ISM, as well as studies of the CGM and IGM traced by sight lines to quasars and gamma-ray bursts. Studies (including those enabled by future generations of extremely large telescopes) of absorption by galaxies against the light of background galaxies will also benefit from our compilation. (2 data files).

  4. Heavy metals effects on forage crops yields and estimation of elements accumulation in plants as affected by soil.

    PubMed

    Grytsyuk, N; Arapis, G; Perepelyatnikova, L; Ivanova, T; Vynograds'ka, V

    2006-02-01

    Heavy metals (Cu, Cd, Pb, Zn) effect on the productivity of forage crops (clover and perennial cereal grasses) and their accumulation in plants, depending on the concentration of these elements in a soil, has been studied in micro-field experiments on three types of soil. The principle objective was to determine regularities of heavy metals migration in a soil-plant system aiming the estimation of permissible levels of heavy metals content in soils with the following elaboration of methods, which regulate the toxicants transfer to plants. Methods of field experiments, agrochemical and atomic absorption analysis were used. Results were statistically treated by Statistica 6.0, S-Plus 6. Experimental results have shown that the intensity of heavy metals accumulation in plants depends on the type of the soil, the species of plants, the physicochemical properties of heavy metals and their content in the soil. Logarithmic interdependency of heavy metals concentration in soils and their accumulation in plants is suggested. However, the strong correlation between the different heavy metals concentrations in the various soils and the yield of crops was not observed. Toxicants accumulation in crops decreased in time.

  5. The heavy-element abundances of AGB stars and the angular momentum conservation model of wind accretion for barium stars

    NASA Astrophysics Data System (ADS)

    Liang, Y. C.; Zhao, G.; Zhang, B.

    2000-11-01

    Adopting new s-process nucleosynthesis scenario and branch s-process path, we calculate the heavy-element abundances of solar metallicity 3Msun thermal pulse asymptotic giant branch (hereafter TP-AGB) stars, and then discuss the correlation between heavy-element abundances and C/O ratio. 13C(alpha ,n)16O reaction is the major neutron source, which is released in radiative condition during the interpulse period, hence gives rise to an efficient s-processing that depends on the 13C profile in the 13C pocket. A second small neutron burst from 22Ne source marginally operates during convective pulses over previously s-processed material diluted with fresh Fe seed and H-burning ashes. The calculated heavy-element abundances and C/O ratio on the surfaces of AGB stars are compared with the observations of MS, S and C (N-type) stars. The observations are characterized by a spread in neutron exposures: 0.5-2.5 times of the corresponding exposures reached in the three zones of the 13C pocket showed by Fig. 1 of Gallino et al. (1998). The evolutionary sequence from M to S to C stars is explained naturally by the calculated heavy-element abundances and C/O ratio. Then the heavy-element abundances on the surfaces of TP-AGB stars are used to calculate the heavy-element overabundances of barium stars, which are generally believed to belong to binary systems and their heavy-element overabundances are produced by the accreting material from the companions (the former TP-AGB stars and the present white dwarfs). To achieve this, firstly, the change equations of binary orbital elements are recalculated by taking the angular momentum conservation in place of the tangential momentum conservation, and the change of delta r/r term is considered; then the heavy-element overabundances of barium stars are calculated, in a self-consistent manner, through wind accretion during successive pulsed mass ejection, followed by mixing. The calculated relationships of heavy-element abundances to

  6. NF-kB activation and its downstream target genes expression after heavy ions exposure

    NASA Astrophysics Data System (ADS)

    Chishti, Arif Ali; Baumstark-Khan, Christa; Hellweg, Christine; Schmitz, Claudia; Koch, Kristina; Feles, Sebastian

    2016-07-01

    To enable long-term human space flight cellular radiation response to densely ionizing radiation needs to be better understood for developing appropriate countermeasures to mitigate acute effects and late radiation risks for the astronaut. The biological effectiveness of accelerated heavy ions (which constitute the most important radiation type in space) with high linear energy transfer (LET) for effecting DNA damage response pathways as a gateway to cell death or survival is of major concern not only for space missions but also for new regimes of tumor radiotherapy. In the current research study, the contribution of NF-κB in response to space-relevant radiation qualities was determined by a NF-κB reporter cell line (HEK-pNF-κB-d2EGFP/Neo L2). The NF-κB dependent reporter gene expression (d2EGFP) after ionizing radiation (X-rays and heavy ions) exposure was evaluated by flow cytometry. Because of differences in the extent of NF-κB activation after X-irradiation and heavy ions exposure, it was expected that radiation quality (LET) might play an important role in the cellular radiation response. In addition, the biological effectiveness (RBE) of NF-κB activation and reduction of cellular survival was examined for heavy ions having a broad range of LET (˜0.3 - 9674 keV/µm). Furthermore, the effect of LET on NF-κB target gene expression was analyzed by real time reverse transcriptase quantitative PCR (RT-qPCR). In this study it was proven that NF-κB activation and NF-κB dependent gene expression comprises an early step in cellular radiation response. Taken together, this study clearly demonstrates that NF-κB activation and NF-κB-dependent gene expression by heavy ions are highest in the LET range of ˜50-200 keV/μupm. The up-regulated chemokines and cytokines (CXCL1, CXCL2, CXCL10, IL-8 and TNF) might be important for cell-cell communication among hit as well as unhit cells (bystander effect). The results obtained suggest the NF-κB pathway to be a

  7. Target Designs for an Inertial Fusion Energy Power Plant Driven by Heavy Ions

    SciTech Connect

    Callahan, D A; Tabak, M

    2001-08-23

    We present two indirect drive inertial fusion targets driven by heavy ions beams for fusion energy production. Because there are uncertainties in the ion beam focal spot size and uncertainties in the accelerator cost, we have tried to design targets that cover a large parameter space. One of the designs requires small ion beam focal spots but produces more than adequate gain at low driver energy (gain 130 from 3.3 MJ of beam energy). The other design allows a large beam spot, but requires more driver energy (gain 55 from 6.7 MJ of beam energy). Target physics issues as well as the implications for the accelerator from each design are discussed.

  8. Heavy metal and trace elements in riparian vegetation and macrophytes associated with lacustrine systems in Northern Patagonia Andean Range.

    PubMed

    Juárez, Andrea; Arribére, María A; Arcagni, Marina; Williams, Natalia; Rizzo, Andrea; Ribeiro Guevara, Sergio

    2016-09-01

    Vegetation associated with lacustrine systems in Northern Patagonia was studied for heavy metal and trace element contents, regarding their elemental contribution to these aquatic ecosystems. The research focused on native species and exotic vascular plant Salix spp. potential for absorbing heavy metals and trace elements. The native species studied were riparian Amomyrtus luma, Austrocedrus chilensis, Chusquea culeou, Desfontainia fulgens, Escallonia rubra, Gaultheria mucronata, Lomatia hirsuta, Luma apiculata, Maytenus boaria, Myrceugenia exsucca, Nothofagus antarctica, Nothofagus dombeyi, Schinus patagonicus, and Weinmannia trichosperma, and macrophytes Hydrocotyle chamaemorus, Isöetes chubutiana, Galium sp., Myriophyllum quitense, Nitella sp. (algae), Potamogeton linguatus, Ranunculus sp., and Schoenoplectus californicus. Fresh leaves were analyzed as well as leaves decomposing within the aquatic bodies, collected from lakes Futalaufquen and Rivadavia (Los Alerces National Park), and lakes Moreno and Nahuel Huapi (Nahuel Huapi National Park). The elements studied were heavy metals Ag, As, Cd, Hg, and U, major elements Ca, K, and Fe, and trace elements Ba, Br, Co, Cr, Cs, Hf, Na, Rb, Se, Sr, and Zn. Geochemical tracers La and Sm were also determined to evaluate contamination of the biological tissues by geological particulate (sediment, soil, dust) and to implement concentration corrections.

  9. Trace elements and heavy metals in the Grand Bay National Estuarine Reserve in the northern Gulf of Mexico

    USDA-ARS?s Scientific Manuscript database

    The Grand Bay National Estuarine Research Reserve has the highest biotic diversity of habitats and offer a reserve of food resources and commercially significant species. Rapid human civilization has led to accumulation of heavy metals and trace elements in estuaries. The Grand Bay National Estuarin...

  10. VizieR Online Data Catalog: Behavior of heavy elements in H-He-Z mixtures (Soubiran+, 2016)

    NASA Astrophysics Data System (ADS)

    Soubiran, F.; Militzer, B.

    2016-11-01

    The core-accretion model for giant planet formation suggests a two-layer picture for the initial structure of Jovian planets, with heavy elements in a dense core and a thick H-He envelope. Late planetesimal accretion and core erosion could potentially enrich the H-He envelope in heavy elements, which is supported by the threefold solar metallicity that was measured in Jupiter's atmosphere by the Galileo entry probe. In order to reproduce the observed gravitational moments of Jupiter and Saturn, models for their interiors include heavy elements, Z, in various proportions. However, their effect on the equation of state of the hydrogen-helium mixtures has not been investigated beyond the ideal mixing approximation. In this article, we report results from ab initio simulations of fully interacting H-He-Z mixtures in order to characterize their equation of state and to analyze possible consequences for the interior structure and evolution of giant planets. Considering C, N, O, Si, Fe, MgO, and SiO2, we show that the behavior of heavy elements in H-He mixtures may still be represented by an ideal mixture if the effective volumes and internal energies are chosen appropriately. In the case of oxygen, we also compute the effect on the entropy. We find the resulting changes in the temperature-pressure profile to be small. A homogeneous distribution of 2% oxygen by mass changes the temperature in Jupiter's interior by only 80K. (3 data files).

  11. Progress towards a high-gain and robust target design for heavy ion fusion

    SciTech Connect

    Henestroza, Enrique; Grant Logan, B.

    2012-07-15

    Recently [E. Henestroza et al., Phys. Plasmas 18, 032702 (2011)], a new inertial-fusion target configuration, the X-target, using one-sided axial illumination has been explored. This class of target uses annular and solid-profile heavy ion beams to compress and ignite deuterium-tritium (DT) fuel that fills the interior of metal cases that have side-view cross sections in the shape of an 'X.' X-targets using all-DT-filled metal cases imploded by three annular ion beams resulted in fuel densities of {approx}50 g/cm{sup 3} at peak compression, and fusion gains of {approx}50, comparable to heavy ion driven hohlraum targets [D. A. Callahan-Miller and M. Tabak, Phys. Plasmas 7, 2083 (2000)]. This paper discusses updated X-target configurations that incorporate inside the case a propellant (plastic) and a pusher (aluminum) surrounding the DT fuel. The updated configurations are capable of assembling higher fuel areal densities {approx}2 g/cm{sup 2} using two annular beams to implode the target to peak DT densities {approx}100 g/cm{sup 3}, followed by a fast-ignition solid ion beam which heats the high-density fuel to thermonuclear temperatures in {approx}200 ps to start the burn propagation, obtaining gains of {approx}300. These targets have been modeled using the radiation-hydrodynamics code HYDRA [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] in two- and three- dimensions to study the properties of the implosion as well as the ignition and burn propagation phases. At typical Eulerian mesh resolutions of a few microns, the aluminum-DT interface shows negligible Rayleigh-Taylor (RT) and Richtmyer-Meshkov instability growth; also, the shear flow of the DT fuel as it slides along the metal X-target walls, which drives the RT and Kelvin Helmholtz instabilities, does not have a major effect on the burning rate. An analytic estimate of the RT instability process at the Al-DT interface shows that the aluminum spikes generated during the pusher deceleration phase would not

  12. Progress towards a high-gain and robust target design for heavy ion fusion

    NASA Astrophysics Data System (ADS)

    Henestroza, Enrique; Grant Logan, B.

    2012-07-01

    Recently [E. Henestroza et al., Phys. Plasmas 18, 032702 (2011)], a new inertial-fusion target configuration, the X-target, using one-sided axial illumination has been explored. This class of target uses annular and solid-profile heavy ion beams to compress and ignite deuterium-tritium (DT) fuel that fills the interior of metal cases that have side-view cross sections in the shape of an "X." X-targets using all-DT-filled metal cases imploded by three annular ion beams resulted in fuel densities of ˜50 g/cm3 at peak compression, and fusion gains of ˜50, comparable to heavy ion driven hohlraum targets [D. A. Callahan-Miller and M. Tabak, Phys. Plasmas 7, 2083 (2000)]. This paper discusses updated X-target configurations that incorporate inside the case a propellant (plastic) and a pusher (aluminum) surrounding the DT fuel. The updated configurations are capable of assembling higher fuel areal densities ˜2 g/cm2 using two annular beams to implode the target to peak DT densities ˜100 g/cm3, followed by a fast-ignition solid ion beam which heats the high-density fuel to thermonuclear temperatures in ˜200 ps to start the burn propagation, obtaining gains of ˜300. These targets have been modeled using the radiation-hydrodynamics code HYDRA [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] in two- and three- dimensions to study the properties of the implosion as well as the ignition and burn propagation phases. At typical Eulerian mesh resolutions of a few microns, the aluminum-DT interface shows negligible Rayleigh-Taylor (RT) and Richtmyer-Meshkov instability growth; also, the shear flow of the DT fuel as it slides along the metal X-target walls, which drives the RT and Kelvin Helmholtz instabilities, does not have a major effect on the burning rate. An analytic estimate of the RT instability process at the Al-DT interface shows that the aluminum spikes generated during the pusher deceleration phase would not reach the ignition zone in time to affect the burning

  13. DETERMINATION OF THE MINIMUM MASSES OF HEAVY ELEMENTS IN THE ENVELOPES OF JUPITER AND SATURN

    SciTech Connect

    Mousis, Olivier; Lunine, Jonathan I.; Marboeuf, Ulysse; Alibert, Yann; Fletcher, Leigh N.; Orton, Glenn S.; Pauzat, Francoise; Ellinger, Yves

    2009-05-10

    We calculate the minimum mass of heavy elements required in the envelopes of Jupiter and Saturn to match the observed oversolar abundances of volatiles. Because the clathration efficiency remains unknown in the solar nebula, we have considered a set of sequences of ice formation in which the fraction of water available for clathration is varied between 0 and 100%. In all the cases considered, we assume that the water abundance remains homogeneous whatever the heliocentric distance in the nebula and directly derives from a gas phase of solar composition. Planetesimals then form in the feeding zones of Jupiter and Saturn from the agglomeration of clathrates and pure condensates in proportions fixed by the clathration efficiency. A fraction of Kr and Xe may have been sequestrated by the H{sup +} {sub 3} ion in the form of stable XeH{sup +} {sub 3} and KrH{sup +} {sub 3} complexes in the solar nebula gas phase, thus implying the formation of at least partly Xe- and Kr-impoverished planetesimals in the feeding zones of Jupiter and Saturn. These planetesimals were subsequently accreted and vaporized into the hydrogen envelopes of Jupiter and Saturn, thus engendering volatiles enrichments in their atmospheres, with respect to hydrogen. Taking into account both refractory and volatile components, and assuming plausible molecular mixing ratios in the gas phase of the outer solar nebula, we show that it is possible to match the observed enrichments in Jupiter and Saturn, whatever the clathration efficiency. Our calculations predict that the O/H enrichment decreases from {approx} 5.5 to 5.1 times (O/H){sub sun} in the envelope of Jupiter and from 15.2 to 14.1 times (O/H){sub sun} in the envelope of Saturn with the growing clathration efficiency in the solar nebula. As a result, the minimum mass of ices needed to be injected in the envelope of Jupiter decreases from {approx} 20.0 to 18.6 M {sub +}, including a mass of water diminishing from 10.4 to 9.3 M {sub +}. In the same

  14. Determination of the Minimum Masses of Heavy Elements in the Envelopes of Jupiter and Saturn

    NASA Astrophysics Data System (ADS)

    Mousis, Olivier; Marboeuf, Ulysse; Lunine, Jonathan I.; Alibert, Yann; Fletcher, Leigh N.; Orton, Glenn S.; Pauzat, Françoise; Ellinger, Yves

    2009-05-01

    We calculate the minimum mass of heavy elements required in the envelopes of Jupiter and Saturn to match the observed oversolar abundances of volatiles. Because the clathration efficiency remains unknown in the solar nebula, we have considered a set of sequences of ice formation in which the fraction of water available for clathration is varied between 0 and 100%. In all the cases considered, we assume that the water abundance remains homogeneous whatever the heliocentric distance in the nebula and directly derives from a gas phase of solar composition. Planetesimals then form in the feeding zones of Jupiter and Saturn from the agglomeration of clathrates and pure condensates in proportions fixed by the clathration efficiency. A fraction of Kr and Xe may have been sequestrated by the H+ 3 ion in the form of stable XeH+ 3 and KrH+ 3 complexes in the solar nebula gas phase, thus implying the formation of at least partly Xe- and Kr-impoverished planetesimals in the feeding zones of Jupiter and Saturn. These planetesimals were subsequently accreted and vaporized into the hydrogen envelopes of Jupiter and Saturn, thus engendering volatiles enrichments in their atmospheres, with respect to hydrogen. Taking into account both refractory and volatile components, and assuming plausible molecular mixing ratios in the gas phase of the outer solar nebula, we show that it is possible to match the observed enrichments in Jupiter and Saturn, whatever the clathration efficiency. Our calculations predict that the O/H enrichment decreases from ~ 5.5 to 5.1 times (O/H)sun in the envelope of Jupiter and from 15.2 to 14.1 times (O/H)sun in the envelope of Saturn with the growing clathration efficiency in the solar nebula. As a result, the minimum mass of ices needed to be injected in the envelope of Jupiter decreases from ~ 20.0 to 18.6 M ⊕, including a mass of water diminishing from 10.4 to 9.3 M ⊕. In the same conditions, the minimum mass of ices needed in the envelope of Saturn

  15. Experimental approach to measure thick target neutron yields induced by heavy ions for shielding

    NASA Astrophysics Data System (ADS)

    Trinh, N. D.; Fadil, M.; Lewitowicz, M.; Brouillard, C.; Clerc, T.; Damoy, S.; Desmezières, V.; Dessay, E.; Dupuis, M.; Grinyer, G. F.; Grinyer, J.; Jacquot, B.; Ledoux, X.; Madeline, A.; Menard, N.; Michel, M.; Morel, V.; Porée, F.; Rannou, B.; Savalle, A.

    2017-09-01

    Double differential (angular and energy) neutron distributions were measured using an activation foil technique. Reactions were induced by impinging two low-energy heavy-ion beams accelerated with the GANIL CSS1 cyclotron: (36S (12 MeV/u) and 208Pb (6.25 MeV/u)) onto thick natCu targets. Results have been compared to Monte-Carlo calculations from two codes (PHITS and FLUKA) for the purpose of benchmarking radiation protection and shielding requirements. This comparison suggests a disagreement between calculations and experiment, particularly for high-energy neutrons.

  16. Transcriptional Targeting in the Airway Using Novel Gene Regulatory Elements

    PubMed Central

    Burnight, Erin R.; Wang, Guoshun; McCray, Paul B.

    2012-01-01

    The delivery of cystic fibrosis transmembrane conductance regulator (CFTR) to airway epithelia is a goal of many gene therapy strategies to treat cystic fibrosis. Because the native regulatory elements of the CFTR are not well characterized, the development of vectors with heterologous promoters of varying strengths and specificity would aid in our selection of optimal reagents for the appropriate expression of the vector-delivered CFTR gene. Here we contrasted the performance of several novel gene-regulatory elements. Based on airway expression analysis, we selected putative regulatory elements from BPIFA1 and WDR65 to investigate. In addition, we selected a human CFTR promoter region (∼ 2 kb upstream of the human CFTR transcription start site) to study. Using feline immunodeficiency virus vectors containing the candidate elements driving firefly luciferase, we transduced murine nasal epithelia in vivo. Luciferase expression persisted for 30 weeks, which was the duration of the experiment. Furthermore, when the nasal epithelium was ablated using the detergent polidocanol, the mice showed a transient loss of luciferase expression that returned 2 weeks after administration, suggesting that our vectors transduced a progenitor cell population. Importantly, the hWDR65 element drove sufficient CFTR expression to correct the anion transport defect in CFTR-null epithelia. These results will guide the development of optimal vectors for sufficient, sustained CFTR expression in airway epithelia. PMID:22447971

  17. The temperature and chronology of heavy-element synthesis in low-mass stars.

    PubMed

    Neyskens, P; Van Eck, S; Jorissen, A; Goriely, S; Siess, L; Plez, B

    2015-01-08

    Roughly half of the heavy elements (atomic mass greater than that of iron) are believed to be synthesized in the late evolutionary stages of stars with masses between 0.8 and 8 solar masses. Deep inside the star, nuclei (mainly iron) capture neutrons and progressively build up (through the slow-neutron-capture process, or s-process) heavier elements that are subsequently brought to the stellar surface by convection. Two neutron sources, activated at distinct temperatures, have been proposed: (13)C and (22)Ne, each releasing one neutron per α-particle ((4)He) captured. To explain the measured stellar abundances, stellar evolution models invoking the (13)C neutron source (which operates at temperatures of about one hundred million kelvin) are favoured. Isotopic ratios in primitive meteorites, however, reflecting nucleosynthesis in the previous generations of stars that contributed material to the Solar System, point to higher temperatures (more than three hundred million kelvin), requiring at least a late activation of (22)Ne (ref. 1). Here we report a determination of the s-process temperature directly in evolved low-mass giant stars, using zirconium and niobium abundances, independently of stellar evolution models. The derived temperature supports (13)C as the s-process neutron source. The radioactive pair (93)Zr-(93)Nb used to estimate the s-process temperature also provides, together with the pair (99)Tc-(99)Ru, chronometric information on the time elapsed since the start of the s-process, which we determine to be one million to three million years.

  18. Heavy metal and trace element concentrations in blood and follicular fluid affect ART outcome.

    PubMed

    Tolunay, Harun Egemen; Şükür, Yavuz Emre; Ozkavukcu, Sinan; Seval, Mehmet Murat; Ateş, Can; Türksoy, Vugar Ali; Ecemiş, Tolga; Atabekoğlu, Cem Somer; Özmen, Batuhan; Berker, Bülent; Sönmezer, Murat

    2016-03-01

    To assess the effects of heavy metal and trace element concentrations in blood and follicular fluid on assisted reproductive technology cycle outcome. A prospective study was conducted between January 2012 and July 2012 in a university hospital infertility clinic. One hundred and one patients with unexplained infertility who underwent intracytoplasmic sperm injection using GnRH-antagonist protocol were recruited. Concentrations of four toxic metals (Cd, Pb, Hg, As) and three trace elements (Cu, Zn, Fe) were measured both in blood and follicular fluid specimens. Patients were evaluated in two groups; the study group consisted of patients with ongoing pregnancy (n=20) and the reference group consisted of patients experienced assisted reproductive technology failure, miscarriage or biochemical pregnancy (n=81). Demographics and cycle parameters were comparable between the groups except for median number of day 3 Grade A embryos. Statistically significant negative correlations were found between blood Pb levels and number of MII oocytes, implantation, clinical pregnancy and ongoing pregnancy rates. Results of the log binomial regression revealed 2.2% lower risk for ongoing pregnancy for each 1μg/dL higher blood Pb concentration while holding the other variables in the model constant (RR 0.978; 95% CI 0.956-0.998; P=.041). Also, the results revealed 71.9% lower risk for ongoing pregnancy for each 1μg/dL higher follicular fluid Cu concentration while holding the other variables in the model constant (RR 0.288; 95% CI 0.085-0.92; P=.039). Blood concentrations of Pb and follicular fluid concentrations of Cu seem to have significant impacts on assisted reproductive technology cycle outcome. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  19. Effects of heavy metal and other elemental additives to activated sludge on growth of Eisenia foetida

    SciTech Connect

    Hartenstein, R.; Neuhauser, E.F.; Narahara, A.

    1981-09-01

    The approximate level at which added concentrations of certain elements would cause an activated sludge to induce a toxic effect upon the growth of Eisenia foetida was determined. During 43 trials on sludge samples obtained throughout 1 year of study, earthworms grew from 3 to 10 mg live wt at hatching to 792 mg +- 18% (mean +- C.V.) in 8 weeks, when sludge was 24/sup 0/C and contained no additives. None of several elements commonly used in microbial growth media enhanced the growth rate of the earthworm. At salt concentrations up to about 6.6% on a dry wt basis, none of six anions tested was in and of itself toxic, while five of 15 cations - Co, Hg, Cu, Ni, and Cd - appeared specifically to inhibit growth rate or cause death. Manganese, Cr, and Pb were innocuous even at the highest levels of application - 22,000, 46,000, and 52,000 mg/kg, respectively. Neither the anionic nor cationic component of certain salts, such as NaCl or NH/sub 4/Cl, could be said to inhibit growth, which occurred only at high concentrations of these salts (about 3.3 and/or 6.6%). Below 7 mmho/cm, toxicity could not be correlated with electrolytic conductance, though higher values may help to explain the nonspecific growth inhibitory effects of salts like NaCl and KCl. Nor could toxicity ever be ascribed to hydrogen ion activity, since sludge pH was not altered even at the highest salt dose. It is concluded that except under very extreme conditions, the levels of heavy metals and salts generally found in activated sludges will not have an adverse affect on the growth of E. foetida.

  20. Heavy-ion radiation induces both activation of multiple endogenous transposable elements and alterations in DNA methylation in rice

    NASA Astrophysics Data System (ADS)

    Zhang, Meng; Sun, Yeqing; Li, Xishan; Xiaolin, Cui; Li, Xiang

    2012-07-01

    Space radiation represents a complex environmental condition in which several interacting factors such as electron, neutron, proton, heavy-ion are involved, which may provoke stress responses and jeopardize genome integrity. Given the inherent property of epigenetic modifications to respond to intrinsic aswell as external perturbations, it is conceivable that epigenetic markers like DNA methylation and transposition may undergo alterations in response to space radiation. Cytosine DNA methylation plays important roles in maintaining genome stability and controlling gene expression. A predominant means for Transposable elements (TEs) to cause genetic instability is via their transpositional activation. To find the detailed molecular characterization of the nature of genomic changes induced by space radiation, the seeds of rice were exposed to 0.02, 0.2, 1, 2 and 20 Gy dose of ^{12}C heavy-ion radiation, respectively. We found that extensive alteration in both DNA methylation and gene expression occurred in rice plants after different dose of heavy-ion radiation. Here we shown that heavy-ion radiation has induced transposition of mPing and Tos17 in rice, which belong to distinct classes including the miniature inverted terminal repeat TEs (MITEs) and long-terminal repeat (LTR) retrotransposons, respectively. mPing and Tos17 mobility were found to correlate with cytosine methylation alteration detected by MSAP and genetic variation detected by AFLP. The result showed that at least in some cases transposition of TEs was associated with cytosine demethylation within the elements. Our results implicate that the heavy-ion radiation represents a potent mutagenic agent that can cause genomic instabilities by eliciting transposition of endogenous TEs in rice. Keywords: Heavy-ion radiation, DNA methylation, Transposable elements, mPing, Tos17

  1. Marine phosphorites as potential resources for heavy rare earth elements and yttrium

    USGS Publications Warehouse

    Hein, James; Koschinsky, Andrea; Mikesell, Mariah; Mizell, Kira; Glenn, Craig R.; Wood, Ray

    2016-01-01

    Marine phosphorites are known to concentrate rare earth elements and yttrium (REY) during early diagenetic formation. Much of the REY data available are decades old and incomplete, and there has not been a systematic study of REY distributions in marine phosphorite deposits that formed over a range of oceanic environments. Consequently, we initiated this study to determine if marine phosphorite deposits found in the global ocean host REY concentrations of high enough grade to be of economic interest. This paper addresses continental-margin (CM) and open-ocean seamount phosphorites. All 75 samples analyzed are composed predominantly of carbonate fluorapatite and minor detrital and authigenic minerals. CM phosphorites have low total REY contents (mean 161 ppm) and high heavy REY (HREY) complements (mean 49%), while seamount phosphorites have 4–6 times higher individual REY contents (except for Ce, which is subequal; mean ΣREY 727 ppm), and very high HREY complements (mean 60%). The predominant causes of higher concentrations and larger HREY complements in seamount phosphorites compared to CM phosphorites are age, changes in seawater REY concentrations over time, water depth of formation, changes in pH and complexing ligands, and differences in organic carbon content in the depositional environments. Potential ore deposits with high HREY complements, like the marine phosphorites analyzed here, could help supply the HREY needed for high-tech and green-tech applications without creating an oversupply of the LREY.

  2. Permanent magnetism of intermetallic compounds between light and heavy transition-metal elements.

    PubMed

    Kumar, P; Kashyap, A; Balamurugan, B; Shield, J E; Sellmyer, D J; Skomski, R

    2014-02-12

    First-principle calculations are used to investigate the intrinsic magnetic properties of intermetallic alloys of the type XMn, where X is a 4d or 5d element and M is Fe or Co. Emphasis is on the hexagonal C14 Laves-phase 1:2 and 1:5 alloys, the latter crystallizing in the CaCu5 structure. These series are of interest in permanent magnetism from fundamental and practical viewpoints, respectively. In the former, the unit cells form a prototypical motif where a heavy atom with high spin-orbit coupling and magnetocrystalline anisotropy is surrounded by many somewhat smaller M atoms with high magnetization, and the latter are Laves-phase derivatives of renewed interest in permanent magnetism. Our DFT calculations predict magnetic moments, magnetizations and anisotropies, as well as formation energies. The results are analyzed across the 4d and 5d series, especially with respect to hybridization effects between 3d and 4d/5d bands.

  3. Nucleosynthesis in Neutrino-driven Winds. II. Implications for Heavy Element Synthesis

    NASA Astrophysics Data System (ADS)

    Hoffman, R. D.; Woosley, S. E.; Qian, Y.-Z.

    1997-06-01

    During the first 20 s of its life, the enormous neutrino luminosity of a neutron star drives appreciable mass loss from its surface. This neutrino-driven wind has been previously identified as a likely site for the r-process. Qian & Woosley have derived, both analytically and numerically, the physical conditions relevant for heavy element synthesis in the wind. These conditions include the entropy (S), the electron fraction (Ye), the dynamic timescale, and the mass loss rate. Here we explore the implications of these conditions for nucleosynthesis. We find that the standard wind models derived in that paper are inadequate to make the r-process, though they do produce some rare species above the iron group. We further determine the general restrictions on the entropy, the electron fraction, and the dynamic timescale that are required to make the r-process. In particular, we derive from nuclear reaction network calculations the conditions required to give a sufficient neutron-to-seed ratio for production of the platinum peak. These conditions range from Ye ~ 0.2 and S <~ 100 baryon-1 for reasonable dynamic timescales of ~0.001-0.1 s, to Ye ~ 0.4-0.495 and S >~ 400 baryon-1 for a dynamic timescale of ~0.1 s. These conditions are also derived analytically to illustrate the physics determining the neutron-to-seed ratio.

  4. Whole Genome Resequencing Reveals Natural Target Site Preferences of Transposable Elements in Drosophila melanogaster

    PubMed Central

    Linheiro, Raquel S.; Bergman, Casey M.

    2012-01-01

    Transposable elements are mobile DNA sequences that integrate into host genomes using diverse mechanisms with varying degrees of target site specificity. While the target site preferences of some engineered transposable elements are well studied, the natural target preferences of most transposable elements are poorly characterized. Using population genomic resequencing data from 166 strains of Drosophila melanogaster, we identified over 8,000 new insertion sites not present in the reference genome sequence that we used to decode the natural target preferences of 22 families of transposable element in this species. We found that terminal inverted repeat transposon and long terminal repeat retrotransposon families present clade-specific target site duplications and target site sequence motifs. Additionally, we found that the sequence motifs at transposable element target sites are always palindromes that extend beyond the target site duplication. Our results demonstrate the utility of population genomics data for high-throughput inference of transposable element targeting preferences in the wild and establish general rules for terminal inverted repeat transposon and long terminal repeat retrotransposon target site selection in eukaryotic genomes. PMID:22347367

  5. Importance of ICPMS for speciation analysis is changing: future trends for targeted and non-targeted element speciation analysis.

    PubMed

    Feldmann, Joerg; Raab, Andrea; Krupp, Eva M

    2017-07-22

    This article is aimed at researchers interested in organic molecules which contain a heteroatom but who have never considered using inductively coupled plasma mass spectrometry (ICPMS) or who have used ICPMS for years and developed numerous methods for analysis of target elemental species. We try to illustrate (1) that ICPMS has been very useful for speciation analysis of metal(loid) target species and that there is now a trend to replace the costly detector with cheaper detection systems for routine target analysis, and (2) that ICPMS has been used and will be used even more in the future for non-targeted analysis of elements which are not normally associated with ICPMS analysis, such as non-metals such as sulfur, phosphorus, chlorine and fluorine. Graphical Abstract Starting with HPLC-ICPMS for non-targeted analysis of heteroatom containing molecules, once target molecule is identified alternative detectors can be used for routine measurements.

  6. Indirect-drive inertial fusion targets for two-sided heavy-ion illumination

    NASA Astrophysics Data System (ADS)

    Remizov, G. N.; Romanov, Yu. A.; Ryabikina, N. A.; Shagaliev, R. M.; Vakhlamova, L. L.; Vatulin, V. V.; Vinokurov, O. A.; Bock, R.; Kang, K.-H.; Maruhn, J. A.

    The properties of heavy-ion induced fusion targets with two-sided illumination and with the converters placed completely inside the hohlraum have been investigated using integrated simulations based on the SATURN and MIMOZA code packages in order to check the results obtained with the view factor method in previous work, which is briefly reviewed. Separate converter simulations show the importance of an accurate treatment of radiation transport and also demonstrate that a converter efficiency of 40 - 80% can be achieved easily depending on the detailed converter material and geometry. For the complete target, a gas fill is shown to be necessary and it turned out to be very important to allow some of the radiation shields to become partially transparent during the evolution. In the most favorable case, an asymmetry in the temperature on the capsule of about 5% was achieved, leading to a reduction of the neutron yield by a factor of 7 compared to an ideally symmetric situation.

  7. A mask for high-intensity heavy-ion beams in the MAYA active target

    NASA Astrophysics Data System (ADS)

    Rodríguez-Tajes, C.; Pancin, J.; Damoy, S.; Roger, T.; Babo, M.; Caamaño, M.; Farget, F.; Grinyer, G. F.; Jacquot, B.; Pérez-Loureiro, D.; Ramos, D.; Suzuki, D.

    2014-12-01

    The use of high-intensity and/or heavy-ion beams in active targets and time-projection chambers is often limited by the strong ionization produced by the beam. Besides the difficulties associated with the saturation of the detector and electronics, beam-related signals may hide the physical events of interest or reduce the detector performance. In addition, space-charge effects may deteriorate the homogeneity of the electric drift field and distort the subsequent reconstruction of particle trajectories. In anticipation of future projects involving such conditions, a dedicated beam mask has been developed and tested in the MAYA active target. Experimental results with a 136Xe beam are presented.

  8. Heavy-Ion Irradiation of Thulium(III) Oxide Targets Prepared by Polymer-Assisted Deposition

    SciTech Connect

    Garcia, Mitch A.; Ali, Mazhar N.; Chang, Noel N.; Parsons-Moss, Tashi; Ashby, Paul D.; Gates, Jacklyn M.; Stavsetra, Liv; Gregorich, Kenneth E.; Nitsche, Heino

    2008-09-15

    Thulium(III) oxide (Tm{sub 2}O{sub 3}) targets prepared by the polymer-assisted deposition (PAD) method were irradiated by heavy-ion beams to test the method's feasibility for nuclear science applications. Targets were prepared on silicon nitride backings (thickness of 1000 nm, 344 {micro}g/cm{sup 2}) and were irradiated with an {sup 40}Ar beam at laboratory frame energy of {approx}210 MeV (50 particle nA). The root mean squared (RMS) roughness prior to irradiation is 1.1 nm for a {approx}250 nm ({approx}220 {micro}g/cm{sup 2}) Tm{sub 2}O{sub 3} target, and an RMS roughness of 2.0 nm after irradiation was measured by atomic force microscopy (AFM). Scanning electron microscopy of the irradiated target reveals no significant differences in surface homogeneity when compared to imaging prior to irradiation. Target flaking was not observed from monitoring Rutherford scattered particles as a function of time.

  9. Hydrodynamic response of solid target heated by heavy ion beams from future facility HIAF

    NASA Astrophysics Data System (ADS)

    Ren, Jieru; Zhao, Yongtao; Cheng, Rui; Xu, Zhongfeng; Xiao, Guoqing

    2017-09-01

    The hydrodynamic response of solid target heated by heavy ion beams at High Intensity Accelerator Facility (HIAF) project was simulated with 1-D computer code. The energy deposition was benchmarked by a 2-D program. The work serves to show the prospect of HIAF project for High Energy Density Physics (HEDP) study, and provide helpful information for the future experiments. Various target materials and schemes are used in the calculation. The results show that in the first phase of HIAF project, the available ion beam is already a powerful tool to generate HED matter with specially designed target, and the second phase of the project will extend the accessible state of matter a big step further. What's more, the hydrodynamic behavior of the target under direct heating indicates that the beam parameter design for HEDP research should come to a compromise, which means, for example, with higher intensity or smaller focal spot, the beam pulse length must be compressed short enough to avoid the target dispersal before the end of the pulse.

  10. Criticality Safety of Low-Enriched Uranium and High-Enriched Uranium Fuel Elements in Heavy Water Lattices

    SciTech Connect

    Pesic, Milan P

    2003-10-15

    The RB reactor was designed as a natural-uranium, heavy water, nonreflected critical assembly in the Vinca Institute of Nuclear Sciences, Belgrade, Yugoslavia, in 1958. From 1962 until 2002, numerous critical experiments were carried out with low-enriched uranium and high-enriched uranium fuel elements of tubular shape, known as the Russian TVR-S fuel assembly type, placed in various heavy water square lattices within the RB cylindrical aluminum tank. Some of these well-documented experiments were selected, described, evaluated, and accepted for inclusion in the 'International Handbook of Evaluated Criticality Safety Benchmark Experiments', contributing to the preservation of a rather small number of heavy water benchmark critical experiments.

  11. Genome-wide target site triplication of Alu elements in the human genome.

    PubMed

    Lee, Wooseok; Mun, Seyoung; Kang, Keunsoo; Hennighausen, Lothar; Han, Kyudong

    2015-05-01

    Alu elements are the most successful short interspersed elements in primate genomes and their retrotransposition is a major source of genomic expansion. Alu elements integrate into genomic regions through target-site primed reverse transcription, which generates target site duplications (TSDs). Unexpectedly, we have identified target site triplications (TSTs) at some loci, where two Alu elements in tandem share one direct repeat. Thus, the three copies of the repeat are present. We located 212 TST loci in the human genome and examined 25 putative human-specific TST loci using PCR validation. As a result, 12 human-specific TST loci were identified. These findings suggest that unequal homologous recombination between TSDs can lead to TST. Through this mechanism, the copy number of Alu elements could have increased in primate genomes without new Alu retrotransposition events. This study provides new insight into the augmentation of Alu elements in the primate genome.

  12. Feasibility study of heavy-ion beams and compound target materials for muon production

    NASA Astrophysics Data System (ADS)

    Sohn, Jae Bum; Lee, Ju Hahn; Kim, Gi Dong; Kim, Yong Kyun

    2015-10-01

    We have investigated the feasibility of using compound materials as targets for muon production by virtue of simulations using a GEANT4 toolkit. A graphite material and two thermostable compound materials, beryllium oxide (BeO) and boron carbide (B4C), were considered as muon production targets, and their muon production rates for a 600-MeV proton beam were calculated and compared. For the thermal analysis, the total heat deposited on the targets by the proton beams and the secondary particles was calculated with the MCNPX code; then, the temperature distribution of target was derived from the calculated heat by using the ANSYS code with consideration of heat transfer mechanisms such as thermal conduction and thermal radiation. In addition, we have investigated whether the heavy-ion beams can be utilized for muon production. For various beam species such as 3He2, 4He, 7Li, 10B and 12C, their muon production rates were calculated and compared with the rates experimentally-obtained for a proton beam.

  13. Secondary neutron-production cross sections from heavy-ioninteractions in composite targets.

    SciTech Connect

    Heilbronn, L.; Iwata, Y.; Iwase,H.; Murakami, T.; Sato, H.; Nakamura, T.; Ronningen, R.M.; Ieki, K.; Gudowska, I.; Sobolevsky, N.

    2005-12-19

    Secondary neutron-production cross-sections have been measured from interactions of 290 MeV/nucleon C and 600 MeV/nucleon Ne in a target composed of simulated Martian regolith and polyethylene, and from 400 MeV/nucleon Ne interactions in wall material from the International Space Station. The data were measured between 5 and 80 deg in the laboratory. We report the double-differential cross sections, angular distributions, and total neutron-production cross sections from all three systems. The spectra from all three systems exhibit behavior previously reported in other heavy-ion, neutron production experiments; namely, a peak at forward angles near the energy corresponding to the beam velocity, with the remaining spectra generated by pre-equilibrium and equilibrium processes. The double differential cross sections are fitted with a moving-source parameterization. Also reported are the data without corrections for neutron flux attenuation in the target and other intervening materials, and for neutron production in non-target materials near the target position. These uncorrected spectra are compared with SHIELD-HIT and PHITS transport model calculations. The transport model calculations reproduce the spectral shapes well, but, on average, underestimate the magnitudes of the cross sections.

  14. Elements toward novel therapeutic targeting of the adrenergic system.

    PubMed

    Ghanemi, Abdelaziz; Hu, Xintian

    2015-02-01

    Adrenergic receptors belong to the family of the G protein coupled receptors that represent important targets in the modern pharmacotherapies. Studies on different physiological and pathophysiological properties of the adrenergic system have led to novel evidences and theories that suggest novel possible targeting of such system in a variety of pathologies and disorders, even beyond the classical known therapeutic possibilities. Herein, those advances have been illustrated with selected concepts and different examples. Furthermore, we illustrated the applications and the therapeutic implications that such findings and advances might have in the contexts of experimental pharmacology, therapeutics and clinic. We hope that the content of this work will guide researches devoted to the adrenergic aspects that combine neurosciences with pharmacology. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Heavy mass elements total half-lives for selected long-lived nuclides

    SciTech Connect

    Holden, N.E.

    1985-01-01

    In the past, many compilations and evaluations of half-lives have been made which have uncritically accepted authors' values and uncertainties. They have merely recommended weight-averaged reported results. This evaluation attempts to reanalyze each experiment in the literature including an estimate of the standard deviation utilizing, where possible, an estimate of the systematic error. This paper constitutes a preliminary step in the process of recommending values. The long-lived nuclides of heavy mass elements are of interest in determining geological ages using the Re-Os or the Lu-Hf dating methods, in supplying information on the p-process (proton capture) of nucleo-synthesis, in providing information on lepton number conservation and the rest mass for the electron neutrino from double ..beta.. decay processes and in the case of tantalum because it represents the first long-lived state which is actually an isomer. Experimental data on the half-lives of selected nuclides have been evaluated and recommended values and uncertainties are presented for the following nuclides: /sup 128/Te, /sup 130/Te, /sup 129/I, /sup 138/La, /sup 144,145/Nd, /sup 146,147,148/Sm, /sup 152/Gd, /sup 154/Dy, /sup 176/Lu, /sup 174/Hf, /sup 180/Ta, /sup 187/Re, /sup 186/Os, /sup 190/Pt, /sup 204,205/Pb and /sup 230,232/Th. It is shown that /sup 204/Pb, which was previously thought to be radioactive, is stable. For /sup 205/Pb, the L electron capture x-rays have been revised for the M and higher x-ray yields. The resulting half-life for /sup 205/Pb is 1.9 +- 0.3 x 10/sup 7/ years. /sup 146/Sm with a half-life of 1.03 +- 0.05 x 10/sup 8/ years is the longest-lived extinct natural nuclide. 21 tabs.

  16. Structural analyses of the storage container for heavy element facility, building-251

    SciTech Connect

    Ng, D S

    1999-01-01

    The Heavy Element Facility, Building 251, contains a series of underground storage vaults which are used for long term storage of nuclear materials. A storage rack with shelves is suspended from the top of each storage vault. The stainless steel containers enclosing the nuclear materials are stored on the shelves. A Hazard & Accident assessment analyzed the vulnerability of this storage system to assaults resulting from natural phenomena and accidents within the building. The assessment considered all racks and their containers to be stored underground and secured in their static, long-term configuration. Moving beyond the static, long-term hazard assessment, the structural analyses were performed to evaluate the storage container against a rare, short duration event. An accidental free drop of a container may occur in a combination of two events: a rare, short-duration earthquake concurrent with an operation of raising the storage rack to a maximum height that the crane is capable of. This hypothetical free drop may occur only to the container in the uppermost shelf of the storage rack. The analyses were the structural evaluation of the storage container to determine the material containment integrity of the storage container after the accident. The evaluation was performed simulating a free drop from the storage rack, with a maximum load in the container, striking/an unyielding surface in the worst orientation. The analyses revealed that, in the very unlikely event of a container drop, the integrity of the hermetic seal of the storage container could be compromised due to plastic deformation of the lid and mating flange. Simple engineering and administrative controls can prevent that from occurring.

  17. Heavy rare earth elements affect early life stages in Paracentrotus lividus and Arbacia lixula sea urchins.

    PubMed

    Oral, Rahime; Pagano, Giovanni; Siciliano, Antonietta; Gravina, Maria; Palumbo, Anna; Castellano, Immacolata; Migliaccio, Oriana; Thomas, Philippe J; Guida, Marco; Tommasi, Franca; Trifuoggi, Marco

    2017-04-01

    Heavy rare earth elements (HREEs) have been scarcely studied for their toxicity, in spite of their applications in several technologies. Thus HREEs require timely investigations for their adverse health effects. Paracentrotus lividus and Arbacia lixula embryos and sperm were exposed to trichloride salts of five HREEs (Dy, Ho, Er, Yb and Lu) and to Ce(III) as a light REE (LREE) reference to evaluate: 1) developmental defects (% DD) in HREE-exposed larvae or in the offspring of HREE-exposed sperm; 2) mitotic anomalies; 3) fertilization success; and 4) reactive oxygen species (ROS) formation, and nitric oxide (NO) and malondialdehyde (MDA) levels. Nominal HREE concentrations were confirmed by inductively coupled plasma mass spectrometry (ICP-MS). HREEs induced concentration-related DD increases in P. lividus and A. lixula larvae, ranging from no significant DD increase at 10(-7)M HREEs up to ≅100% DD at 10(-5)M HREE. Larvae exposed to 10(-5)M Ce(III) resulted in less severe DD rates compared to HREEs. Decreased mitotic activity and increased aberration rates were found in HREE-exposed P. lividus embryos. Significant increases in ROS formation and NO levels were found both in HREE-exposed and in Ce(III) embryos, whereas only Ce(III), but not HREEs resulted in significant increase in MDA levels. Sperm exposure to HREEs (10(-5)-10(-4)M) resulted in a concentration-related decrease in fertilization success along with increase in offspring damage. These effects were significantly enhanced for Dy(III), Ho(III), Er(III) and Yb(III), compared to Lu(III) and to Ce(III). HREE-associated toxicity affected embryogenesis, fertilization, cytogenetic and redox endpoints showing different toxicities of tested HREEs. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. HAT-P-26b: A Neptune-mass exoplanet with a well-constrained heavy element abundance.

    PubMed

    Wakeford, Hannah R; Sing, David K; Kataria, Tiffany; Deming, Drake; Nikolov, Nikolay; Lopez, Eric D; Tremblin, Pascal; Amundsen, David S; Lewis, Nikole K; Mandell, Avi M; Fortney, Jonathan J; Knutson, Heather; Benneke, Björn; Evans, Thomas M

    2017-05-12

    A correlation between giant-planet mass and atmospheric heavy elemental abundance was first noted in the past century from observations of planets in our own Solar System and has served as a cornerstone of planet-formation theory. Using data from the Hubble and Spitzer Space Telescopes from 0.5 to 5 micrometers, we conducted a detailed atmospheric study of the transiting Neptune-mass exoplanet HAT-P-26b. We detected prominent H2O absorption bands with a maximum base-to-peak amplitude of 525 parts per million in the transmission spectrum. Using the water abundance as a proxy for metallicity, we measured HAT-P-26b's atmospheric heavy element content ([Formula: see text] times solar). This likely indicates that HAT-P-26b's atmosphere is primordial and obtained its gaseous envelope late in its disk lifetime, with little contamination from metal-rich planetesimals. Copyright © 2017, American Association for the Advancement of Science.

  19. HAT-P-26b: A Neptune-mass exoplanet with a well-constrained heavy element abundance

    NASA Astrophysics Data System (ADS)

    Wakeford, Hannah R.; Sing, David K.; Kataria, Tiffany; Deming, Drake; Nikolov, Nikolay; Lopez, Eric D.; Tremblin, Pascal; Amundsen, David S.; Lewis, Nikole K.; Mandell, Avi M.; Fortney, Jonathan J.; Knutson, Heather; Benneke, Björn; Evans, Thomas M.

    2017-05-01

    A correlation between giant-planet mass and atmospheric heavy elemental abundance was first noted in the past century from observations of planets in our own Solar System and has served as a cornerstone of planet-formation theory. Using data from the Hubble and Spitzer Space Telescopes from 0.5 to 5 micrometers, we conducted a detailed atmospheric study of the transiting Neptune-mass exoplanet HAT-P-26b. We detected prominent H2O absorption bands with a maximum base-to-peak amplitude of 525 parts per million in the transmission spectrum. Using the water abundance as a proxy for metallicity, we measured HAT-P-26b’s atmospheric heavy element content (4.8-4.0+21.5 times solar). This likely indicates that HAT-P-26b’s atmosphere is primordial and obtained its gaseous envelope late in its disk lifetime, with little contamination from metal-rich planetesimals.

  20. Paddy soil — A suitable target for monitoring heavy metal pollution by magnetic proxies

    NASA Astrophysics Data System (ADS)

    Yan, H. T.; Hu, S. Y.; Blaha, U.; Rösler, W.; Duan, X. M.; Appel, E.

    2011-10-01

    A preliminary magnetic study around Meishan steel mill in Nanjing (SE China) was carried out combining geochemical analysis with scanning electron microscopy (SEM) to prove that paddy soil can be a suitable target for environmental study on heavy metal pollution. Magnetic background investigation showed a strong variation in this area due to different land uses and soil types. Magnetic susceptibilities (MS) measured on forest soils are much higher than in paddy fields, and values below 20 cm of the soil surface in forest with parent material of Xiashu loess are several times higher than in paddy soil with parent material of fluvisol. Measurements on vertical profiles show that paddy soil has a very low and stable magnetic background with mass-specific MS around 15 × 10 - 8 m 3 kg - 1 . A strong enhancement of MS values is found in the upper ~ 20 cm of paddy soil predominated by multidomain and pseudo single domain magnetite. However, relatively low S-ratios (0.57 to 0.85) reveal a significant contribution of imperfect anti-ferromagnetic minerals. Detailed research on a paddy soil core at site C719 near the steel mill indicates strong correlation between magnetic mineral concentration-related parameters (χ, ARM, SIRM) and heavy metal concentrations of Cu, Pb and Zn. In addition, typical anthropogenic Fe-spherules are detected in top paddy soil by means of SEM, which indicates that the increase of susceptibility in upper soil is mainly caused by steel mill emission. Mapping of MS in paddy fields across the steel mill area shows a decrease of MS with the distance to the major emission zone. Positive correlation between χ and Zn is found by measuring surface soil samples around the steel mill. Because of low background and high homogeneity of the ~ 20 cm uppermost mixing layer paddy fields are especially suitable for magnetic surface mapping of heavy metal pollution.

  1. Neutron yield and dose equivalent from heavy ion interactions on thick target

    NASA Astrophysics Data System (ADS)

    Sunil, C.; Saxena, A.; Choudhury, R. K.; Pant, L. M.

    2004-12-01

    Thick target neutron yields and angular distributions are essential for shielding calculations for ion beam accelerators. Most of such measurements available in the literature are for proton and alpha particle bombardments. In case of heavy ions, very few data are available in the energy region of 20 MeV amu -1 and below. We report here the neutron yield, double differential neutron yields and neutron dose equivalent values obtained from the double differential yields at 0° and 90° with respect to the beam for various heavy ions in the energy range of 3.5-7.0 MeV amu -1. Pulse shape discrimination was used to separate neutrons from gamma rays and time of flight technique was used for energy measurement. The double differential neutron yields were fitted using the moving source model and the nuclear temperature and source intensity are also determined. The neutron yield increases inversely with the mass of the projectile except in the case of 7Li where the yields are much lower than that obtained from 11B. This could be due to the structure of the loosely bound 7Li projectile. The neutron dose equivalent shows increasing trend with the decrease of the mass of the projectile.

  2. Heavy-ion beam induced effects in enriched gadolinium target films prepared by molecular plating

    NASA Astrophysics Data System (ADS)

    Mayorov, D. A.; Tereshatov, E. E.; Werke, T. A.; Frey, M. M.; Folden, C. M.

    2017-09-01

    A series of enriched gadolinium (Gd, Z = 64) targets was prepared using the molecular plating process for nuclear physics experiments at the Cyclotron Institute at Texas A&M University. After irradiation with 48Ca and 45Sc projectiles at center-of-target energies of Ecot = 3.8-4.7 MeV/u, the molecular films displayed visible discoloration. The morphology of the films was examined and compared to the intact target surface. The thin films underwent a heavy-ion beam-induced density change as identified by scanning electron microscopy and α-particle energy loss measurements. The films became thinner and more homogenous, with the transformation occurring early on in the irradiation. This transformation is best described as a crystalline-to-amorphous phase transition induced by atomic displacement and destruction of structural order of the original film. The chemical composition of the thin films was surveyed using energy dispersive spectroscopy and X-ray diffraction, with the results confirming the complex chemistry of the molecular films previously noted in other publications.

  3. Secondary neutron-production cross sections from heavy-ion interactions in composite targets

    SciTech Connect

    Heilbronn, L.; Iwata, Y.; Murakami, T.; Iwase, H.; Sato, H.; Nakamura, T.; Ronningen, R.M.; Ieki, K.; Gudowska, I.; Sobolevsky, N.

    2006-02-15

    Secondary neutron-production cross sections have been measured from interactions of 290 MeV/nucleon C and 600 MeV/nucleon Ne in a target composed of simulated Martian regolith and polyethylene, and from 400 MeV/nucleon Ne interactions in wall material from the International Space Station. The data were measured between 5 deg. and 80 deg. in the laboratory. We report the double-differential cross sections, angular distributions, and total neutron-production cross sections from all three systems. The spectra from all three systems exhibit behavior previously reported in other heavy-ion neutron-production experiments, namely, a peak at forward angles near the energy corresponding to the beam velocity, with the remaining spectra generated by pre-equilibrium and equilibrium processes. The double-differential cross sections are fitted with a moving-source parametrization. Also reported are the data without corrections for neutron flux attenuation in the target and other intervening materials and for neutron production in nontarget materials near the target position. These uncorrected spectra are compared with SHIELD-HIT and PHITS transport model calculations. The transport model calculations reproduce the spectral shapes well but, on average, underestimate the magnitudes of the cross sections.

  4. Depth of origin of sputtered atoms for elemental targets

    NASA Astrophysics Data System (ADS)

    Shulga, V. I.; Eckstein, W.

    1998-12-01

    The mean depth of origin of sputtered atoms is an important characteristic of the sputtering process. There exist several theoretical and experimental determinations of the escape depth with different results. To clear up the situation, in the present work a systematic computer simulation study of the mean depth of origin of sputtered atoms is performed. The Monte Carlo program TRIM.SP and the lattice code OKSANA are applied to calculate the distribution of depth of origin and the dependences of the mean depth of origin on the atomic density, N, projectile energy, E, the angle of incidence, α, projectile and target atomic species, Z1 and Z2, as well as the simulation model.

  5. Effect of heavy metals on silencing of engineered long interspersed element-1 retrotransposon in nondividing neuroblastoma cell line.

    PubMed

    Habibi, Laleh; Shokrgozar, Mohammad Ali; Motamedi, Mahdieh; Akrami, Seyed Mohammad

    2013-01-01

    L1 retrotransposons are the most active mobile DNA elements in human genome. Unregulated L1 retrotransposition may have deleterious effect by disrupting vital genes and inducing genomic instabilities. Therefore, human cells control L1 elements by silencing their activities through epigenetic mechanisms. It has been shown that cell division and heavy metals stimulate the frequency of L1 activities. Removal of silencing by L1 motivators may restart L1 element functions. Here, we have proposed that weather neurotoxic environmental heavy metals (as L1 stimulating factors) have a role in removing L1 silencing and restating its activities in nondividing neuronal cells. L1-RP green fluorescent protein (GFP)-tagged knock-in human neuroblastoma clones were prepared. Single-cell clone was treated with mitomycin-c combined with nontoxic and toxic concentrations of iron (Fe), copper (Cu), and mercury (Hg). Silencing status of engineered L1 elements in dividing and nondividing cells was determined through measuring the amount of GFP expressing cells with flow cytometry. The cytotoxic effect of mitomycin-c combined with metals was measured by MTT assay. Hg in nondividing cells and Fe, Cu, and Hg in dividing neuroblastoma cells could significantly remove L1 silencing. Also, mitomycin-c treatment did not have any effect on metal toxicity status in neuroblastoma cells. Totally, our findings have shown that cell division has a role in removing L1 silencing as well as L1 retrotransposition induced by environmental heavy metals. It has been also indicated that Hg at all concentrations could remove silencing of engineered L1 element regardless of cell cycle state.

  6. [Comparison of heavy metal elements between natural and plantation forests in a subtropical Montane forest].

    PubMed

    Nie, Ming; Wan, Jia-Rong; Chen, Xiao-Feng; Wang, Li; Li, Bo; Chen, Jia-Kuan

    2011-11-01

    Heavy metals as one of major pollutants is harmful to the health of forest ecosystems. In the present paper, the concentrations of thirteen heavy metals (Fe, Al, Ti, Cr, Cu, Mn, V, Zn, Ni, Co, Pb, Se and Cd) were compared between natural and plantation forests in the Mt. Lushan by ICP-AES and atomic absorption spectroscopy. The results suggest that the soil of natural forest had higher concentrations of Fe, Al, Ti, Cu, Mn, V, Zn, Ni, Co, Pb, Se, and Cd than the plantation forest except for Cr. The soil of natural forest had a higher level of heavy metals than that of the plantation forest as a whole. This might be due to that the natural forest has longer age than the plantation forest, and fixed soil heavy metals take a longer period of time than the plantation forest.

  7. Regulatory Elements in Vectors for Efficient Generation of Cell Lines Producing Target Proteins

    PubMed Central

    Maksimenko, O.; Gasanov, N. B.; Georgiev, P.

    2015-01-01

    To date, there has been an increasing number of drugs produced in mammalian cell cultures. In order to enhance the expression level and stability of target recombinant proteins in cell cultures, various regulatory elements with poorly studied mechanisms of action are used. In this review, we summarize and discuss the potential mechanisms of action of such regulatory elements. PMID:26483956

  8. Levels of some toxic elements and frequency of bacterial heavy metal resistance in sediment and sea water.

    PubMed

    Altug, Gulsen; Balkis, Nuray

    2009-02-01

    The Golden Horn Estuary located in the Istanbul region of Turkey has been thought to be a heavily polluted area since the 1950s: the concentration of the elements, which include heavy metals such as Cu2+, Mn2+, Ni2+, Zn2+, Pb2+, Cd2+, and Fe2+, was therefore investigated in sediment and water samples of the area. The resistance of Enterobacteriaceae members to some heavy metal salts was investigated to determine levels of metal-resistant bacteria in the Golden Horn Estuary after the environmental restoration project in 1998. The sediment samples were collected with an Ekman-Grab in the period from November 2002 to February 2004 from depths of 4-15 m and analyzed by means of an atomic absorption spectrophotometer. Analyses of average heavy metals of sediment samples yielded the following results: 131.5 ppm Cu, 405.5 ppm Mn, 46.5 ppm Ni, 191.2 ppm Zn, 81.5 ppm Pb and 27668 ppm Fe. As with water, Ni concentrations in sediment were found lower than that in limit values. Frequency of heavy metals resistance to Cu, Zn, Fe, Ni, Mn, Pb and Cd was detected as an average of 65.0%, 64.4%, 62.5%, 38.4%, 37.3%, 36.2% and 28.4%, respectively in a total of 192 strains isolated from sediment samples. It was observed that there was no statistically significant difference among the results of analyses with respect to sampling dates. Despite the environmental restoration project in 1998, our study results showed that heavy metal levels were still high in the sediment and this situation induced the tolerance of bacteria to some heavy metals.

  9. HEAVY ELEMENT NUCLEOSYNTHESIS IN THE BRIGHTEST GALACTIC ASYMPTOTIC GIANT BRANCH STARS

    SciTech Connect

    Karakas, Amanda I.; Garcia-Hernandez, D. A.

    2012-05-20

    We present updated calculations of stellar evolutionary sequences and detailed nucleosynthesis predictions for the brightest asymptotic giant branch (AGB) stars in the Galaxy with masses between 5 M{sub Sun} and 9 M{sub Sun }, with an initial metallicity of Z = 0.02 ([Fe/H] = 0.14). In our previous studies we used the Vassiliadis and Wood mass-loss rate, which stays low until the pulsation period reaches 500 days after which point a superwind begins. Vassiliadis and Wood noted that for stars over 2.5 M{sub Sun} the superwind should be delayed until P Almost-Equal-To 750 days at 5 M{sub Sun }. We calculate evolutionary sequences where we delay the onset of the superwind to pulsation periods of P Almost-Equal-To 700-800 days in models of M = 5, 6, and 7 M{sub Sun }. Post-processing nucleosynthesis calculations show that the 6 and 7 M{sub Sun} models produce the most Rb, with [Rb/Fe] Almost-Equal-To 1 dex, close to the average of most of the Galactic Rb-rich stars ([Rb/Fe] Almost-Equal-To 1.4 {+-} 0.8 dex). Changing the rate of the {sup 22}Ne +{alpha} reactions results in variations of [Rb/Fe] as large as 0.5 dex in models with a delayed superwind. The largest enrichment in heavy elements is found for models that adopt the NACRE rate of the {sup 22}Ne({alpha}, n){sup 25}Mg reaction. Using this rate allows us to best match the composition of most of the Rb-rich stars. A synthetic evolution algorithm is then used to remove the remaining envelope resulting in final [Rb/Fe] of Almost-Equal-To 1.4 dex although with C/O ratios >1. We conclude that delaying the superwind may account for the large Rb overabundances observed in the brightest metal-rich AGB stars.

  10. Condensates from stellar protoplanetary nebulae: Implications for heavy element and volatile enrichment in extrasolar planets

    NASA Astrophysics Data System (ADS)

    Johnson, T. V.; Lunine, J. I.; Mousis, O.

    2010-12-01

    The study of planetary systems around other stars is rapidly expanding to include spectral data on the composition of extrasolar planets. These can be interpreted in the context of what we know about the origin and evolution of our own solar system. Planetary characteristics are strongly affected by the composition of the solid material condensed from the protoplanetary stellar nebula in the planet forming regions, particularly the relative proportions of condensed volatile ices to refractory silicates and metals. This affects the relative amounts of enrichment of heavy elements and trapped volatiles of giant planets forming by core nucleated accretion and also the composition and evolution of rock-ice planetesimals which form satellites, Kuiper belt objects and asteroids, as well as solid, ‘terrestrial’ planets. Estimates of the rock-metal fraction of material incorporated by the ‘hot Jupiter’ HD 189733b have been used by Mousis et al. [1] to study the range of volatile abundances in the planet’s envelope. Since the parent star of HD 189733b has solar metallicity, solar abundance values from [2]were used, following the treatment of solar nebula condensates in [3]. However, while the compositions of main sequence stars are broadly similar to solar due to nucleosynthesis and the mixing of supernovae material, there are significant differences observed in the photospheric elemental abundances of the parent stars of extrasolar planets. We assume that this reflects equivalent differences in the composition of the protoplanetary nebulae from which these planets formed. Using data from two recent surveys of stars with extrasolar planets [4, 5] we have calculated the rock-metal fraction, fr-m, of ice-silicate condensates for 25 stars with a range of metallicity and composition. For solar composition fr-m varies from ~0.47 to ~0.76 depending on the redox state of C in the gas phase (CO-rich to CO-poor). The sample of extrasolar planet parent stars studied

  11. Periodic Table Target: A Game that Introduces the Biological Significance of Chemical Element Periodicity

    ERIC Educational Resources Information Center

    Sevcik, Richard S.; McGinty, Ragan L.; Schultz, Linda D.; Alexander, Susan V.

    2008-01-01

    Periodic Table Target, a game for middle school or high school students, familiarizes students with the form of the periodic table and the biological significance of different elements. The Periodic Table Target game board is constructed as a class project, and the game is played to reinforce the content. Students are assigned several elements…

  12. Periodic Table Target: A Game that Introduces the Biological Significance of Chemical Element Periodicity

    ERIC Educational Resources Information Center

    Sevcik, Richard S.; McGinty, Ragan L.; Schultz, Linda D.; Alexander, Susan V.

    2008-01-01

    Periodic Table Target, a game for middle school or high school students, familiarizes students with the form of the periodic table and the biological significance of different elements. The Periodic Table Target game board is constructed as a class project, and the game is played to reinforce the content. Students are assigned several elements…

  13. Observations of Heavy Element Abundances over a Broad Energy Range in 3He-rich Solar Energetic Particle Events

    NASA Astrophysics Data System (ADS)

    Wiedenbeck, M. E.; Mason, G. M.; Cohen, C. M.; Leske, R. A.; Cummings, A. C.; Dwyer, J. R.; Mazur, J. E.; Mewaldt, R. A.; Stone, E. C.; von Rosenvinge, T. T.

    2006-05-01

    During the maximum of solar cycle 23 a number of 3He-rich solar energetic particle (SEP) events with measurable intensities of heavy elements (Z≥6) at energies >10 MeV/nuc were observed with instrumentation on the Advanced Composition Explorer (ACE) spacecraft. This represents a relatively small fraction of all the 3He-rich SEP events that were detected since heavy-ion intensities at these energies were frequently too low to be measured. Using data from two ACE instruments (SIS covering ~10--60 MeV/nuc and ULEIS ~0.2--1 MeV/nuc) we have investigated heavy element abundances over a broad energy range in this special set of events. We report the average abundance ratios and the correlations between different ratios in the two energy intervals. Furthermore we compare the results from the two different energy ranges, both statistically and on an event-by-event basis. In addition, we compare the statistical properties observed in the SIS and ULEIS data sets with previously-published results obtained at intermediate energies (~1--3 MeV/nuc) from instruments on ISEE-3 during the maximum of solar cycle 21 (Mason et al. 1986, Reames et al. 1994).

  14. Systematics of cross sections for target K-vacancy production in heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Peng, Yong

    Cross sections for K-shell ionization by heavy ions have been determined from the measurements of target K x-ray yields. The measurements were performed with Ar, Kr, and Xe ions at energies from 2.5 to 25 MeV/amu and self-supported metallic foil targets of Al, Ti, Cu, Zr, Ag, Sm, and Ta. The x-ray yields were measured with a Si(Li) detector, while the projectile ions were counted in coincidence with the x-rays using a plastic scintillation detector. In addition, the amount of secondary K-shell ionization and the degree of simultaneous L-shell ionization in primary K-shell ionizing collisions were assessed by performing high-resolution x-ray measurements on targets of Al, Ti, V, Co, and Cu with a curved crystal spectrometer. The results of the high resolution measurements revealed that the apparent average L-shell spectator vacancy fraction at the time of Kalpha x-ray emission, pL, may be represented by a universal function of the Geometrical Model's parameter X for Z2 = 17-32. Multiple-vacancy Kalpha fluorescence yields and corrections for K-shell ionization by secondary processes were determined with the aid of the high resolution spectra for the targets Al, Ti, and Cu. Fluorescence yields for the other targets were determined using an extrapolation procedure. The resulting K-vacancy production cross sections for 2.5 to 6 MeV/amu projectiles were compared with a limited amount of available experimental data and shown to be in relatively good agreement. The ECPSSR predictions for all the targets except Al agreed reasonably well with experimental cross sections for Ar projectiles. The experimental cross sections for K-vacancy production in Al, Ti, Cu, Zr, and Ag were greatly deviated from the ECPSSR predictions. The cross sections for Kr on Sm and Ta were in good agreement with theory. The scaling properties of the Kalpha x-ray production cross sections were examined and a semiempirical "universal" curve was deduced that reproduces the measured cross sections to

  15. Parametric Study of Heavy Element Distributions in SiC Grains

    NASA Astrophysics Data System (ADS)

    Howard, W. M.; Arnould, M.

    1992-07-01

    Recent determinations of the isotopic composition of a series of heavy elements in small-sized (micron) SiC grains have provided nuclear astrophysics with a wealth of compositional clues as to the astrophysical origin of these grains. In particular, the isotopic compositions of Si, Ca, Ti, Sr, Kr, Xe, Ba, Nd, and Sm (1,2,3,4) have been measured and exhibit significant deviations from their solar system counterparts. Although various astrophysical sources of these anomalous compositions have been proposed, e.g., AGB or Wolf-Rayet stars, no consistent picture has emerged. We t parametrized model in order to investigate in as a broad way as possible the neutron exposures or ranges of such exposures that could replicate the series of measured isotopic compositions without relying on any specific (and highly uncertain) astrophysical scenario. This study is in the same spirit in which one has studied the s-process as well as the r- and p- processes with parametrized models in order to understand the bulk solar system composition. We find that we can reproduce the general trends of the isotopic data for the elements from krypton through samarium with a rather simple neutron exposure history. We also show how one can relax the classical assumption of a two- component mixing curve. We interpret the linear correlations in the three-isotope plots as a mixture of components with slightly different neutron exposures. The neutron captures are calculated by a method described earlier (5,6), where we use the latest compilation of neutron capture rates and of the temperature and density dependent beta-decay rates. For the initial composition we take a solar-like composition (7). We define a standard model by tau = 0.006 mb-1, a neutron exposure timescale of 5x10**6 s and a temperature kT = 30 keV, this implying a neutron density of 5x10**9 cm-3. This model defines a standard set of abundances. A series of computations has been performed with different tau values and initial

  16. Two-loop massive operator matrix elements and unpolarized heavy flavor production at asymptotic values Q≫m

    NASA Astrophysics Data System (ADS)

    Bierenbaum, Isabella; Blümlein, Johannes; Klein, Sebastian

    2007-09-01

    We calculate the O(αs2) massive operator matrix elements for the twist-2 operators, which contribute to the heavy flavor Wilson coefficients in unpolarized deeply inelastic scattering in the region Q≫m. The calculation has been performed using light-cone expansion techniques. We confirm an earlier result obtained in [M. Buza, Y. Matiounine, J. Smith, R. Migneron, W.L. van Neerven, Nucl. Phys. B 472 (1996) 611, arxiv:/hep-ph/9601302]. The calculation is carried out without using the integration-by-parts method and in Mellin space using harmonic sums, which lead to a significant compactification of the analytic results derived previously. The results allow to determine the heavy flavor Wilson coefficients for F(x,Q) to O(αs2) and for F(x,Q) to O(αs3) for all but the power suppressed terms ∝(/Q)k,k⩾1.

  17. Heavy-ion inertial fusion: influence of target gain on accelerator parameters for vacuum-propagation regimes in reaction chambers

    SciTech Connect

    Mark, J.W.K.; Bangerter, R.O.; Barletta, W.A.; Fawley, W.M.; Judd, D.L.

    1982-03-04

    Target physics imposes requirements on the design of inertial fusion drivers. The influence of beam propagation in near vacuum fusion reaction chambers is evaluated for the relation between target gain and the phase-space requirements of heavy-ion accelerators. Initial results suggest that neutralization of the ion beam has a much greater positive effect than the deleterious one of beam stripping provided that the fusion chamber pressure is < 10/sup -3/ torr (of Li vapor or equivalent).

  18. Element accumulation in boreal bryophytes, lichens and vascular plants exposed to heavy metal and sulfur deposition in Finland.

    PubMed

    Salemaa, Maija; Derome, John; Helmisaari, Heljä-Sisko; Nieminen, Tiina; Vanha-Majamaa, Ilkka

    2004-05-25

    Macronutrient (N, P, K, Mg, S, Ca), heavy metal (Fe, Zn, Mn, Cu, Ni, Cd, Pb) and Al concentrations in understorey bryophytes, lichens and vascular plant species growing in Scots pine forests at four distances from the Harjavalta Cu-Ni smelter (0.5, 2, 4 and 8 km) were compared to those at two background sites in Finland. The aim was to study the relationship between element accumulation and the distribution of the species along a pollution gradient. Elevated sulfur, nitrogen and heavy metal concentrations were found in all species groups near the pollution source. Macronutrient concentrations tended to decrease in the order: vascular plants>bryophytes>lichens, when all the species groups grew on the same plot. Heavy metal concentrations (except Mn) were the highest in bryophytes, followed by lichens, and were the lowest in vascular plants. In general, vascular plants, being capable of restricting the uptake of toxic elements, grew closer to the smelter than lichens, while bryophytes began to increase in the understorey vegetation at further distances from the smelter. A pioneer moss (Pohlia nutans) was an exception, because it accumulated considerably higher amounts of Cu and Ni than the other species and still survived close to the smelter. The abundance of most of the species decreased with increasing Cu and Ni concentrations in their tissues. Cetraria islandica, instead, showed a positive relationship between the abundance and Cu, Ni and S concentrations of the thallus. It is probable that, in addition to heavy metals, sporadically high SO(2) emissions have also affected the distribution of the plant species.

  19. Explosive Nucleosynthesis in Magnetohydrodynamical Jets from Collapsars. II --- Heavy-Element Nucleosynthesis of s, p, r-Processes

    NASA Astrophysics Data System (ADS)

    Ono, M.; Hashimoto, M.; Fujimoto, S.; Kotake, K.; Yamada, S.

    2012-10-01

    We investigate the nucleosynthesis in a massive star of 70 M_{⊙} with solar metallicity in the main sequence stage. The helium core mass after hydrogen burning corresponds to 32 M_{⊙}. Nucleosynthesis calculations have been performed during the stellar evolution and the jetlike supernova explosion of a collapsar model. We focus on the production of elements heavier than iron group nuclei. Nucleosynthesis calculations have been accomplished consistently from hydrostatic to dynamic stages by using large nuclear reaction networks, where the weak s-, p-, and r-processes are taken into account. We confirm that s-elements of 60 < A < 90 are highly overproduced relative to the solar abundances in the hydrostatic nucleosynthesis. During oxygen burning, p-elements of A > 90 are produced via photodisintegrations of seed s-elements. However, the produced p-elements are disintegrated in later stages except for ^{180}Ta. In the explosive nucleosynthesis, elements of 90 < A < 160 are significantly overproduced relative to the solar values owing to the r-process, which is very different from the results of spherical explosion models. Only heavy p-elements (N > 50) are overproduced via the p-process because of the low peak temperatures in the oxygen- and neon-rich layers. Compared with the previous study of r-process nucleosynthesis calculations in the collapsar model of 40 M_{⊙} by Fujimoto et al. [S. Fujimoto, M. Hashimoto, K. Kotake and S. Yamada, Astrophys. J. 656 (2007), 382; S. Fujimoto, N. Nishimura and M. Hashimoto, Astrophys. J. 680 (2008), 1350], our jet model cannot contribute to the third peak of the solar r-elements and intermediate p-elements, which have been much produced because of the distribution of the lowest part of electron fraction in the ejecta. Averaging the overproduction factors over the progenitor masses with the use of Salpeter's IMF, we suggest that the 70 M_{⊙} star could contribute to the solar weak s}-elements of 60 < A < 90 and neutron

  20. Heavy element effects in the diagonal Born–Oppenheimer correction within a relativistic spin-free Hamiltonian

    SciTech Connect

    Imafuku, Yuji; Abe, Minori; Schmidt, Michael W.; Hada, Masahiko

    2016-03-22

    Methodologies beyond the Born–Oppenheimer (BO) approximation are nowadays important to explain high precision spectroscopic measurements. Most previous evaluations of the BO correction are, however, focused on light-element molecules and based on a nonrelativistic Hamiltonian, so no information about the BO approximation (BOA) breakdown in heavy-element molecules is available. The present work is the first to investigate the BOA breakdown for the entire periodic table, by considering scalar relativistic effects in the Diagonal BO correction (DBOC). In closed shell atoms, the relativistic EDBOC scales as Z1.25 and the nonrelativistic EDBOC scales as Z1.17, where Z is the atomic number. Hence, we found that EDBOC becomes larger in heavy element atoms and molecules, and the relativistic EDBOC increases faster than nonrelativistic EDBOC. We have further investigated the DBOC effects on properties such as potential energy curves, spectroscopic parameters, and various energetic properties. The DBOC effects for these properties are mostly affected by the lightest atom in the molecule. Furthermore, in X2 or XAt molecule (X = H, Li, Na, K, Rb, and Cs) the effect of DBOC systematically decreases when X becomes heavier but in HX molecules, the effect of DBOC seems relatively similar among all the molecules.

  1. Heavy element effects in the diagonal Born–Oppenheimer correction within a relativistic spin-free Hamiltonian

    DOE PAGES

    Imafuku, Yuji; Abe, Minori; Schmidt, Michael W.; ...

    2016-03-22

    Methodologies beyond the Born–Oppenheimer (BO) approximation are nowadays important to explain high precision spectroscopic measurements. Most previous evaluations of the BO correction are, however, focused on light-element molecules and based on a nonrelativistic Hamiltonian, so no information about the BO approximation (BOA) breakdown in heavy-element molecules is available. The present work is the first to investigate the BOA breakdown for the entire periodic table, by considering scalar relativistic effects in the Diagonal BO correction (DBOC). In closed shell atoms, the relativistic EDBOC scales as Z1.25 and the nonrelativistic EDBOC scales as Z1.17, where Z is the atomic number. Hence, wemore » found that EDBOC becomes larger in heavy element atoms and molecules, and the relativistic EDBOC increases faster than nonrelativistic EDBOC. We have further investigated the DBOC effects on properties such as potential energy curves, spectroscopic parameters, and various energetic properties. The DBOC effects for these properties are mostly affected by the lightest atom in the molecule. Furthermore, in X2 or XAt molecule (X = H, Li, Na, K, Rb, and Cs) the effect of DBOC systematically decreases when X becomes heavier but in HX molecules, the effect of DBOC seems relatively similar among all the molecules.« less

  2. Transposable Element Targeting by piRNAs in Laurasiatherians with Distinct Transposable Element Histories

    PubMed Central

    Vandewege, Michael W.; Platt, Roy N.; Ray, David A.; Hoffmann, Federico G.

    2016-01-01

    PIWI proteins and PIWI-interacting RNAs (piRNAs) are part of a cellular pathway that has evolved to protect genomes against the proliferation of transposable elements (TEs). PIWIs and piRNAs assemble into complexes that are involved in epigenetic and post-transcriptional repression of TEs. Most of our understanding of the mechanisms of piRNA-mediated TE silencing comes from fruit fly and mouse models. However, even in these well-studied animals it is unclear how piRNA responses relate to variable TE expression and whether the strength of the piRNA response affects TE content over time. Here, we assessed the evolutionary interactions between TE and piRNAs in a statistical framework using three nonmodel laurasiatherian mammals as a study system: dog, horse, and a vesper bat. These three species diverged ∼80 million years ago and have distinct genomic TE contents. By comparing species with distinct TE landscapes, we aimed to identify clear relationships among TE content, expression, and piRNAs. We found that the TE subfamilies that are the most transcribed appear to elicit the strongest “ping-pong” response. This was most evident among long interspersed elements, but the relationships between expression and ping-pong pilRNA (piRNA-like) expression were more complex among SINEs. SINE transcripts were equally abundant in the dog and horse yet new SINE insertions were relatively rare in the horse genome, where we identified a stronger piRNA response. Our analyses suggest that the piRNA response can have a strong impact on the TE composition of a genome. However, our results also suggest that the presence of a robust piRNA response is apparently not sufficient to stop TE mobilization and accumulation. PMID:27060702

  3. On the internal pollution mechanisms in the globular cluster NGC 6121 (M4): heavy-element abundances and AGB models

    NASA Astrophysics Data System (ADS)

    D'Orazi, V.; Campbell, S. W.; Lugaro, M.; Lattanzio, J. C.; Pignatari, M.; Carretta, E.

    2013-07-01

    Globular clusters display significant variations in their light-element content, pointing to the existence of a second stellar generation formed from the ejecta of an earlier generation. The nature of these internal polluters is still a matter of debate: the two most popular scenarios indicate intermediate-mass asymptotic giant branch (IM-AGB) stars and fast rotating massive stars. Abundances determination for some key elements can help distinguish between these competitor candidates. We present in this paper Y abundances for a sample of 103 red giant branch stars in NGC 6121. Within measurement errors, we find that the [Y/Fe] is constant in this cluster contrary to a recent suggestion. For a subsample of six stars we also find [Rb/Fe] to be constant, consistent with previous studies showing no variation in other s-process elements. We also present a new set of stellar yields for IM-AGB stellar models of 5 and 6 M⊙, including heavy element s-process abundances. The uncertainties on the mass-loss rate, the mixing length parameter and the nuclear reaction rates have a major impact on the stellar abundances. Within the IM-AGB pollution scenario, the constant abundance of heavy elements inside the cluster requires a marginal s-process efficiency in IM-AGB stars. Such a constrain could still be satisfied by the present models assuming a stronger mass-loss rate. The uncertainties mentioned above are limiting the predictive power of IM-AGB models. For these reasons, at the moment we are not able to clearly rule out their role as main polluters of the second population stars in globular clusters.

  4. The Origins of Light and Heavy R-process Elements Identified by Chemical Tagging of Metal-poor Stars

    NASA Astrophysics Data System (ADS)

    Tsujimoto, Takuji; Shigeyama, Toshikazu

    2014-11-01

    Growing interests in neutron star (NS) mergers as the origin of r-process elements have sprouted since the discovery of evidence for the ejection of these elements from a short-duration γ-ray burst. The hypothesis of a NS merger origin is reinforced by a theoretical update of nucleosynthesis in NS mergers successful in yielding r-process nuclides with A > 130. On the other hand, whether the origin of light r-process elements are associated with nucleosynthesis in NS merger events remains unclear. We find a signature of nucleosynthesis in NS mergers from peculiar chemical abundances of stars belonging to the Galactic globular cluster M15. This finding combined with the recent nucleosynthesis results implies a potential diversity of nucleosynthesis in NS mergers. Based on these considerations, we are successful in the interpretation of an observed correlation between [light r-process/Eu] and [Eu/Fe] among Galactic halo stars and accordingly narrow down the role of supernova nucleosynthesis in the r-process production site. We conclude that the tight correlation by a large fraction of halo stars is attributable to the fact that core-collapse supernovae produce light r-process elements while heavy r-process elements such as Eu and Ba are produced by NS mergers. On the other hand, stars in the outlier, composed of r-enhanced stars ([Eu/Fe] gsim +1) such as CS22892-052, were exclusively enriched by matter ejected by a subclass of NS mergers that is inclined to be massive and consist of both light and heavy r-process nuclides.

  5. THE ORIGINS OF LIGHT AND HEAVY R-PROCESS ELEMENTS IDENTIFIED BY CHEMICAL TAGGING OF METAL-POOR STARS

    SciTech Connect

    Tsujimoto, Takuji; Shigeyama, Toshikazu

    2014-11-01

    Growing interests in neutron star (NS) mergers as the origin of r-process elements have sprouted since the discovery of evidence for the ejection of these elements from a short-duration γ-ray burst. The hypothesis of a NS merger origin is reinforced by a theoretical update of nucleosynthesis in NS mergers successful in yielding r-process nuclides with A > 130. On the other hand, whether the origin of light r-process elements are associated with nucleosynthesis in NS merger events remains unclear. We find a signature of nucleosynthesis in NS mergers from peculiar chemical abundances of stars belonging to the Galactic globular cluster M15. This finding combined with the recent nucleosynthesis results implies a potential diversity of nucleosynthesis in NS mergers. Based on these considerations, we are successful in the interpretation of an observed correlation between [light r-process/Eu] and [Eu/Fe] among Galactic halo stars and accordingly narrow down the role of supernova nucleosynthesis in the r-process production site. We conclude that the tight correlation by a large fraction of halo stars is attributable to the fact that core-collapse supernovae produce light r-process elements while heavy r-process elements such as Eu and Ba are produced by NS mergers. On the other hand, stars in the outlier, composed of r-enhanced stars ([Eu/Fe] ≳ +1) such as CS22892-052, were exclusively enriched by matter ejected by a subclass of NS mergers that is inclined to be massive and consist of both light and heavy r-process nuclides.

  6. Behavior and distribution of heavy metals including rare Earth elements, thorium, and uranium in sludge from industry water treatment plant and recovery method of metals by biosurfactants application.

    PubMed

    Gao, Lidi; Kano, Naoki; Sato, Yuichi; Li, Chong; Zhang, Shuang; Imaizumi, Hiroshi

    2012-01-01

    In order to investigate the behavior, distribution, and characteristics of heavy metals including rare earth elements (REEs), thorium (Th), and uranium (U) in sludge, the total and fractional concentrations of these elements in sludge collected from an industry water treatment plant were determined and compared with those in natural soil. In addition, the removal/recovery process of heavy metals (Pb, Cr, and Ni) from the polluted sludge was studied with biosurfactant (saponin and sophorolipid) elution by batch and column experiments to evaluate the efficiency of biosurfactant for the removal of heavy metals. Consequently, the following matters have been largely clarified. (1) Heavy metallic elements in sludge have generally larger concentrations and exist as more unstable fraction than those in natural soil. (2) Nonionic saponin including carboxyl group is more efficient than sophorolipid for the removal of heavy metals in polluted sludge. Saponin has selectivity for the mobilization of heavy metals and mainly reacts with heavy metals in F3 (the fraction bound to carbonates) and F5 (the fraction bound to Fe-Mn oxides). (3) The recovery efficiency of heavy metals (Pb, Ni, and Cr) reached about 90-100% using a precipitation method with alkaline solution.

  7. Behavior and Distribution of Heavy Metals Including Rare Earth Elements, Thorium, and Uranium in Sludge from Industry Water Treatment Plant and Recovery Method of Metals by Biosurfactants Application

    PubMed Central

    Gao, Lidi; Kano, Naoki; Sato, Yuichi; Li, Chong; Zhang, Shuang; Imaizumi, Hiroshi

    2012-01-01

    In order to investigate the behavior, distribution, and characteristics of heavy metals including rare earth elements (REEs), thorium (Th), and uranium (U) in sludge, the total and fractional concentrations of these elements in sludge collected from an industry water treatment plant were determined and compared with those in natural soil. In addition, the removal/recovery process of heavy metals (Pb, Cr, and Ni) from the polluted sludge was studied with biosurfactant (saponin and sophorolipid) elution by batch and column experiments to evaluate the efficiency of biosurfactant for the removal of heavy metals. Consequently, the following matters have been largely clarified. (1) Heavy metallic elements in sludge have generally larger concentrations and exist as more unstable fraction than those in natural soil. (2) Nonionic saponin including carboxyl group is more efficient than sophorolipid for the removal of heavy metals in polluted sludge. Saponin has selectivity for the mobilization of heavy metals and mainly reacts with heavy metals in F3 (the fraction bound to carbonates) and F5 (the fraction bound to Fe-Mn oxides). (3) The recovery efficiency of heavy metals (Pb, Ni, and Cr) reached about 90–100% using a precipitation method with alkaline solution. PMID:22693485

  8. Two Maize Genes Are Each Targeted Predominantly by Distinct Classes of Mu Elements

    PubMed Central

    Hardeman, K. J.; Chandler, V. L.

    1993-01-01

    The Mutator transposable element system of maize has been used to isolate mutations at many different genes. Six different classes of Mu transposable elements have been identified. An important question is whether particular classes of Mu elements insert into different genes at equivalent frequencies. To begin to address this question, we used a small number of closely related Mutator plants to generate multiple independent mutations at two different genes. The overall mutation frequency was similar for the two genes. We then determined what types of Mu elements inserted into the genes. We found that each of the genes was preferentially targeted by a different class of Mu element, even when the two genes were mutated in the same plant. Possible explanations for these findings are discussed. These results have important implications for cloning Mu-tagged genes as other genes may also be resistant or susceptible to the insertion of particular classes of Mu elements. PMID:8307329

  9. Effects of heavy elements in the sludge conveyed by the 2011 tsunami on human health and the recovery of the marine ecosystem

    NASA Astrophysics Data System (ADS)

    Sera, K.; Goto, S.; Takahashi, C.; Saitoh, Y.; Yamauchi, K.

    2014-01-01

    The 2011 tsunami not only caused significant damage, but also drew a large amount of sludge from the bottom of the sea. This may have exerted negative effects on human health. In order to evaluate changes in elemental concentrations in the body before and after the tsunami, we collected long hairs from victims of the disaster. Furthermore, sludge and plant samples were collected from three prefectures. The sludge samples on land were found to be still contaminated with heavy elements. The concentrations of heavy elements in the soils and plants gathered from the same tidelands decreased after one year. In hair analyses, no clear changes have been observed in heavy element concentrations measured before and after the tsunami. However, the concentration of some essential elements, such as Cu, Ca and Mg, showed a decreasing tendency after the tsunami.

  10. NUMEN Project @ LNS : Heavy ions double charge exchange reactions towards the 0νββ nuclear matrix element determination

    SciTech Connect

    Agodi, C. Calabretta, L.; Calanna, A.; Carbone, D.; Cavallaro, M.; Colonna, M.; Cuttone, G.; Finocchiaro, P.; Pandola, L.; Rifuggiato, D.; Tudisco, S.; Cappuzzello, F.; Greco, V.; Bonanno, D. L.; Bongiovanni, D. G.; Longhitano, F.; Branchina, V.; Foti, A.; Lo Presti, D.; Lanzalone, G.; and others

    2015-10-28

    In the NUMEN Project it is proposed an innovative technique to access the nuclear matrix elements entering in the expression of the life-time of the neutrinoless double beta decay, using relevant cross sections of double charge exchange reactions. A key aspect is the use of MAGNEX large acceptance magnetic spectrometer, for the detection of the ejectiles, and of the INFN Laboratori Nazionali del Sud (LNS) K800 Superconducting Cyclotron (CS), for the acceleration of the required high resolution and low emittance heavy-ion beams.

  11. Ab initio approaches for the determination of heavy element energetics: Ionization energies of trivalent lanthanides (Ln = La-Eu)

    SciTech Connect

    Peterson, Charles; Penchoff, Deborah A.; Wilson, Angela K.

    2015-11-21

    An effective approach for the determination of lanthanide energetics, as demonstrated by application to the third ionization energy (in the gas phase) for the first half of the lanthanide series, has been developed. This approach uses a combination of highly correlated and fully relativistic ab initio methods to accurately describe the electronic structure of heavy elements. Both scalar and fully relativistic methods are used to achieve an approach that is both computationally feasible and accurate. The impact of basis set choice and the number of electrons included in the correlation space has also been examined.

  12. Lead, platinum, and other heavy elements in the primary cosmic radiation: HEAO-3 results ssc wg032961 cb553097

    NASA Technical Reports Server (NTRS)

    Waddington, C. J.; Binns, W. R.; Brewster, N. R.; Fixsen, D. J.; Garrard, T. L.; Israel, M. H.; Klarmann, J.; Newport, B. J.; Stone, E. C.

    1985-01-01

    An observation of the abundances of cosmic-ray lead and platinum-group nuclei using data from the HEAO-3 Heavy Nuclei Experiment (HNE) which consisted of ion chambers mounted on both sides of a plastic Cerenkov counter is reported. Further analysis with more stringent selections, inclusion of additional data, and a calibration at the LBL Bevalac, have allowed obtaining the abundance ratio of lead and the platinum group of elements for particles that had a cutoff rigidity R sub c 5 GV.

  13. Lead, platinum, and other heavy elements in the primary cosmic radiation: HEAO-3 results ssc wg032961 cb553097

    NASA Technical Reports Server (NTRS)

    Waddington, C. J.; Binns, W. R.; Brewster, N. R.; Fixsen, D. J.; Garrard, T. L.; Israel, M. H.; Klarmann, J.; Newport, B. J.; Stone, E. C.

    1985-01-01

    An observation of the abundances of cosmic-ray lead and platinum-group nuclei using data from the HEAO-3 Heavy Nuclei Experiment (HNE) which consisted of ion chambers mounted on both sides of a plastic Cerenkov counter is reported. Further analysis with more stringent selections, inclusion of additional data, and a calibration at the LBL Bevalac, have allowed obtaining the abundance ratio of lead and the platinum group of elements for particles that had a cutoff rigidity R sub c 5 GV.

  14. Mitochondria as an important target in heavy metal toxicity in rat hepatoma AS-30D cells.

    PubMed

    Belyaeva, Elena A; Dymkowska, Dorota; Wieckowski, Mariusz R; Wojtczak, Lech

    2008-08-15

    The mechanisms of toxic effects of divalent cations of three heavy metals Hg, Cd and Cu in rat ascites hepatoma AS-30D cells cultivated in vitro were compared. It was found that the toxicity of these ions, applied in the micromolar range (10-500 microM), decreased from Hg(2+) (most toxic) to Cu(2+) (least toxic). Hg(2+) and Cd(2+) produced a high percentage of cell death by both necrosis and apoptosis, whereas Cu(2+) at concentrations up to 500 microM was weakly effective. Hg(2+) at concentration of 10 microM appeared slightly uncoupling (i.e., stimulated resting state respiration and decreased the mitochondrial transmembrane potential), whereas it exerted a strong inhibitory effect on the respiratory chain and rapid dissipation of the membrane potential at higher concentrations. Cu(2+) had inhibitory effect on cell respiration only at 500 microM concentration and after incubation of 48 h but produced a significant uncoupling effect at lower concentrations. Cu(2+) induced an early and sharp increase of intracellular production of reactive oxygen species (ROS). The action of Hg(2+) and Cd(2+) on ROS generation was biphasic. They stimulated ROS generation within the cells at low concentrations and at short incubation times but decreased ROS generation at higher concentrations and at longer incubation. It is concluded that mitochondria are an important target for toxic effects of Hg(2+), Cd(2+) and Cu(2+) in AS-30D rat hepatoma cells.

  15. Finite element modeling simulation-assisted design of integrated microfluidic chips for heavy metal ion stripping analysis

    NASA Astrophysics Data System (ADS)

    Hong, Ying; Zou, Jianhua; Ge, Gang; Xiao, Wanyue; Gao, Ling; Shao, Jinjun; Dong, Xiaochen

    2017-10-01

    In this article, a transparent integrated microfluidic device composed of a 3D-printed thin-layer flow cell (3D-PTLFC) and an S-shaped screen-printed electrode (SPE) has been designed and fabricated for heavy metal ion stripping analysis. A finite element modeling (FEM) simulation is employed to optimize the shape of the electrode, the direction of the inlet pipeline, the thin-layer channel height and the sample flow rate to enhance the electron-enrichment efficiency for stripping analysis. The results demonstrate that the S-shaped SPE configuration matches the channel in 3D-PTLFC perfectly for the anodic stripping behavior of the heavy metal ions. Under optimized conditions, a wide linear range of 1–80 µg l‑1 is achieved for Pb2+ detection with a limit of 0.3 µg l‑1 for the microfluidic device. Thus, the obtained integrated microfluidic device proves to be a promising approach for heavy metal ions stripping analysis with low cost and high performance.

  16. Recent advances and future perspectives of nanosized zero- valent iron for extraction of heavy elements from metallurgical sludges

    NASA Astrophysics Data System (ADS)

    Mikhailov, I. Yu; Levina, V. V.; Kolesnikov, E. A.; Chuprunov, K. O.; Gusev, A. A.; Godymchuk, A. Yu; Kuznetsov, D. V.

    2016-01-01

    Advanced oxidation processes with nanosized zero-valent iron have presented great potential in wastewater treatment technology and now experience both increasing popularity and reliable technical improvements. Besides wastewater treatment, there is another promising application for an emerging technology of iron nanoparticles - as Fenton-like catalyst for extraction of valuable elements from poor and secondary raw materials such as metallurgical sludges. In present research, we carried out a set of experiments with emphasis on the physicochemical mechanisms and their relationship to the performance. In particular, we examined complex acidic - hydrogen peroxide leaching of zinc from blast furnace sludge with nanosized zero-valent iron as Fenton-like catalyst. Results of the experiments showed promising potential for subsequent application in extraction of heavy and rare-earth elements.

  17. Sources and contents of heavy metals and other trace elements in animal manure

    USDA-ARS?s Scientific Manuscript database

    Trace elements take part in various physiological functions including enzyme formation, vitamin formation, metabolism, and electron transport in animals. Thus, trace elements are added to livestock and poultry diets to prevent diseases, improve weight gains and feed conversion, and increase egg prod...

  18. Sources and Contents of Heavy Metals and Other Trace Elements in Animal Manure

    USDA-ARS?s Scientific Manuscript database

    Trace elements are natural and added components of livestock and poultry feeds. Appropriate amounts of these trace elements in the diet of livestock and poultry ensures both health and reproduction. Unfortunately, many times trace metals that are added to livestock diets by producers or feed compani...

  19. Mapping of light elements with the ANSTO high energy heavy ion microprobe

    NASA Astrophysics Data System (ADS)

    Siegele, Rainer; Cohen, David D.

    2000-03-01

    7.62 MeV He was used to study the distribution of a wide range of elements in mineral sands. At this energy both He induced X-ray emission and a high energy resonance in oxygen can be applied simultaneously. The two techniques were used to study the distribution of elements ranging from sulfur to zirconium as well as oxygen.

  20. [Monitoring of heavy metals and trace elements in the air, fruits and vegetables and soil in the province of Catania (Italy)].

    PubMed

    Ferrante, Margherita; Fiore, Maria; Ledda, Caterina; Cicciù, Francesca; Alonzo, Elena; Fallico, Roberto; Platania, Francesco; Di Mauro, Rosario; Valenti, Lina; Sciacca, Salvatore

    2013-01-01

    Contamination of fruits and vegetables with heavy metals can result from anthropogenic events (car or factory emissions, poor management of sewage and industrial waste) or from natural events (volcanic activity and geological soil matrix). The chemical and toxicological characteristics of heavy metals can have an impact on human health through several mechanisms. Other metals, on the other hand, are essential for maintenance of physiological and biochemical human processes, are protective against many diseases and must be present in the diet because they cannot be synthesized by the human body. The purpose of this study was to assess the presence of heavy metals and trace elements both in fruit and vegetable products widely consumed in the province of Catania (Sicily, Italy) and in various environmental matrices (air, water and land), and to investigate possible sources of contamination. Fruit and vegetable products (tomatoes, lettuce, spinach, eggplants, potatoes, zucchini, grapes, apples and pears) were sampled (n = 60) from the towns of Adrano, Biancavilla and Mazzarrone. These locations were selected for their geomorphology, climate and cultivation characteristics. Levels of lead, cadmium, nickel, copper, zinc, vanadium and selenium in fruit, vegetables, air and water samples were determined using atomic absorption spectrometer with graphite furnace Perkin-Elmer AAnalyst 800 while soil samples were evaluated by the atomic emission spectrometer Optima 2000 DV Perkin-Elmer. The presence of mercury was evaluated by atomic absorption spectrometry with cold vapor technique. Study results revealed widespread contamination of fruit and vegetables and mainly due to use of fertilizers and to volcanic activity. A strategy targeting the entire food chain is essential for ensuring food safety and consumer protection and maintaining contaminants at levels which are not hazardous to health.

  1. MOLYBDENUM, RUTHENIUM, AND THE HEAVY r-PROCESS ELEMENTS IN MODERATELY METAL-POOR MAIN-SEQUENCE TURNOFF STARS

    SciTech Connect

    Peterson, Ruth C.

    2013-05-01

    The ratios of elemental abundances observed in metal-poor stars of the Galactic halo provide a unique present-day record of the nucleosynthesis products of its earliest stars. While the heaviest elements were synthesized by the r- and s-processes, dominant production mechanisms of light trans-ironic elements were obscure until recently. This work investigates further our 2011 conclusion that the low-entropy regime of a high-entropy wind (HEW) produced molybdenum and ruthenium in two moderately metal-poor turnoff stars that showed extreme overabundances of those elements with respect to iron. Only a few, rare nucleosynthesis events may have been involved. Here we determine abundances for Mo, Ru, and other trans-Fe elements for 28 similar stars by matching spectral calculations to well-exposed near-UV Keck HIRES spectra obtained for beryllium abundances. In each of the 26 turnoff stars with Mo or Ru line detections and no evidence for s-process production (therefore old), we find Mo and Ru to be three to six times overabundant. In contrast, the maximum overabundance is reduced to factors of three and two for the neighboring elements zirconium and palladium. Since the overproduction peaks sharply at Mo and Ru, a low-entropy HEW is confirmed as its origin. The overabundance level of the heavy r-process elements varies significantly, from none to a factor of four, but is uncorrelated with Mo and Ru overabundances. Despite their moderate metallicity, stars in this group trace the products of different nucleosynthetic events: possibly very few events, possibly events whose output depended on environment, metallicity, or time.

  2. Effects of alloying elements on the formation of < c >-component loops in Zr alloy Excel under heavy ion irradiation.

    SciTech Connect

    Idrees, Yasir; Francis, Elisabeth M.; Yao, Zhongwen; Korinek, Andreas; Kirk, Marquis A.; Sattari, Mohammad; Preuss, Michael; Daymond, M. R.

    2015-05-14

    We report here the microstructural changes occurring in the zirconium alloy Excel (Zr-3.5 wt% Sn-0.8Nb-0.8Mo-0.2Fe) during heavy ion irradiation. In situ irradiation experiments were conducted at reactor operating temperatures on two Zr Excel alloy microstructures with different states of alloying elements, with the states achieved by different solution heat treatments. In the first case, the alloying elements were mostly concentrated in the beta (beta) phase, whereas, in the second case, large Zr-3(Mo,Nb,Fe)(4) secondary phase precipitates (SPPs) were grown in the alpha (alpha) phase by long term aging. The heavy ion induced damage and resultant compositional changes were examined using transmission electron microscopy (TEM) in combination with scanning transmission electron microscope (STEM)-energy dispersive x-ray spectroscopy (EDS) mapping. Significant differences were seen in microstructural evolution between the two different microstructures that were irradiated under similar conditions. Nucleation and growth of < c >-component loops and their dependence on the alloying elements are a major focus of the current investigation. It was observed that the < c >-component loops nucleate readily at 100, 300, and 400 degrees C after a threshold incubation dose (TID), which varies with irradiation temperature and the state of alloying elements. It was found that the TID for the formation of < c >-component loops increases with decrease in irradiation temperature. Alloying elements that are present in the form of SPPs increase the TID compared to when they are in the beta phase solid solution. Dose and temperature dependence of loop size and density are presented. Radiation induced redistribution and clustering of alloying elements (Sn, Mo, and Fe) have been observed and related to the formation of < c >-component loops. It has been shown that at the higher temperature tests, irradiation induced dissolution of precipitates occurs whereas irradiation induced

  3. Non-Targeted Effects and the Dose Response for Heavy Ion Tumorigenesis

    NASA Technical Reports Server (NTRS)

    Chappell, Lori J.; Cucinotta, Francis A.

    2010-01-01

    There is no human epidemiology data available to estimate the heavy ion cancer risks experienced by astronauts in space. Studies of tumor induction in mice are a necessary step to estimate risks to astronauts. Previous experimental data can be better utilized to model dose response for heavy ion tumorigenesis and plan future low dose studies.

  4. [Intake of trace elements and heavy metals with the diet of 2-14 years old children. Zinc, manganese, copper, fluoride, iodine, selen; lead, cadmium, mercury (author's transl)].

    PubMed

    Stolley, H; Kersting, M; Droese, W

    1981-04-01

    For 2-14 year old children the intake of the trace elements zinc, manganese, copper, fluoride, iodine, selen, and of the heavy metals, lead, cadmium and mercury is calculated from their food intake. The results give a representative statement of the average supply of trace elements and of the average intake of heavy metals with the diet of children in the Federal Republic of Germany. It is shown that the choice of foodstuffs for the diet has an important influence on the supply of trace elements.

  5. Elemental Abundances of Ultra-Heavy Galactic Cosmic Rays from the SuperTIGER Instrument

    NASA Astrophysics Data System (ADS)

    Murphy, Ryan

    2016-07-01

    The SuperTIGER (Trans-Iron Galactic Element Recorder) experiment was launched on a long-duration balloon flight from Williams Field, Antarctica, on December 8, 2012. The instrument measured the relative elemental abundances of Galactic Cosmic Rays (GCR) for charge (Z) Z>10 with excellent charge resolution, displaying well resolved individual element peaks for 10 ≤ Z ≤ 40. During its record-breaking 55-day flight, SuperTIGER collected ˜4.73 x10^{6} Iron nuclei, ˜8 times as many as detected by its predecessor, TIGER, with charge resolution at iron of 0.17 cu. SuperTIGER measures charge (Z) and energy (E) using a combination of three scintillator and two Cherenkov detectors, and employs a scintillating fiber hodoscope for event trajectory determination. The SuperTIGER data have been analyzed to correct for instrument effects and remove events that underwent nuclear interactions within the instrument. The data include more than 600 events in the charge range 30 < Z ≤ 40. SuperTIGER is the first experiment to resolve elemental abundances of every element in this charge range with high statistics and single-element resolution. The relative abundances of the galactic cosmic ray source have been derived from the measured relative elemental abundances using atmospheric and interstellar propagations. The SuperTIGER measured abundances are generally consistent with previous experimental results from TIGER and ACE-CRIS, with improved statistical precision. The SuperTIGER results confirm the earlier results from TIGER, supporting a model of cosmic-ray origin in OB associations, with preferential acceleration of refractory elements over volatile elements ordered by atomic mass (A). A second SuperTIGER Antarctic flight is planned for December 2017. Details of the instrument, flight, data analysis, and ongoing preparations will be presented.

  6. U.S. Department of Energy Office of Science Heavy Elements Program. Final Report

    SciTech Connect

    Clark. S. B.; Ewing, R.

    2005-05-01

    In our first funding cycle, much time was spent developing protocols for characterizing and working with samples containing transuranium isotopes and obtaining preliminary experimental data on non-f-element systems.

  7. Non-Targeted Effects and the Dose Response for Heavy Ion Tumorigenesis

    NASA Technical Reports Server (NTRS)

    Chappelli, Lori J.; Cucinotta, Francis A.

    2010-01-01

    BACKGROUND: There is no human epidemiology data available to estimate the heavy ion cancer risks experienced by astronauts in space. Studies of tumor induction in mice are a necessary step to estimate risks to astronauts. Previous experimental data can be better utilized to model dose response for heavy ion tumorigenesis and plan future low dose studies. DOSE RESPONSE MODELS: The Harderian Gland data of Alpen et al.[1-3] was re-analyzed [4] using non-linear least square regression. The data set measured the induction of Harderian gland tumors in mice by high-energy protons, helium, neon, iron, niobium and lanthanum with LET s ranging from 0.4 to 950 keV/micron. We were able to strengthen the individual ion models by combining data for all ions into a model that relates both radiation dose and LET for the ion to tumor prevalence. We compared models based on Targeted Effects (TE) to one motivated by Non-targeted Effects (NTE) that included a bystander term that increased tumor induction at low doses non-linearly. When comparing fitted models to the experimental data, we considered the adjusted R2, the Akaike Information Criteria (AIC), and the Bayesian Information Criteria (BIC) to test for Goodness of fit.In the adjusted R2test, the model with the highest R2values provides a better fit to the available data. In the AIC and BIC tests, the model with the smaller values of the summary value provides the better fit. The non-linear NTE models fit the combined data better than the TE models that are linear at low doses. We evaluated the differences in the relative biological effectiveness (RBE) and found the NTE model provides a higher RBE at low dose compared to the TE model. POWER ANALYSIS: The final NTE model estimates were used to simulate example data to consider the design of new experiments to detect NTE at low dose for validation. Power and sample sizes were calculated for a variety of radiation qualities including some not considered in the Harderian Gland data

  8. Design of a distributed radiator target for inertial fusion driven from two sides with heavy ion beams

    SciTech Connect

    Tabak, M.; Callahan-Miller, D.

    1997-11-10

    We describe the status of a distributed radiator heavy ion target design. In integrated calculations this target ignited and produced 390-430 MJ of yieldwhen driven with 5.8-6.5 MJ of 3-4 GeV Pb ions. The target has cylindrical symmetry with disk endplates. The ions uniformly illuminate these endplates in a 5mm radius spot. We discuss the considerations which led to this design together with some previously unused design features: low density hohlraum walls in approximate pressure balance with internal low-Z fill materials, radiationsymmetry determined by the position of the radiator materials and particle ranges, and early time pressure symmetry possibly influenced by radiation shims. We discuss how this target scales to lower input energy or to lower beam power. Variant designs with more realistic beam focusing strategies are also discussed. We show the tradeoffs required for targets which accept higher particle energies.

  9. Mitochondria as an important target in heavy metal toxicity in rat hepatoma AS-30D cells

    SciTech Connect

    Belyaeva, Elena A. Dymkowska, Dorota; Wieckowski, Mariusz R.; Wojtczak, Lech

    2008-08-15

    The mechanisms of toxic effects of divalent cations of three heavy metals Hg, Cd and Cu in rat ascites hepatoma AS-30D cells cultivated in vitro were compared. It was found that the toxicity of these ions, applied in the micromolar range (10-500 {mu}M), decreased from Hg{sup 2+} (most toxic) to Cu{sup 2+} (least toxic). Hg{sup 2+} and Cd{sup 2+} produced a high percentage of cell death by both necrosis and apoptosis, whereas Cu{sup 2+} at concentrations up to 500 {mu}M was weakly effective. Hg{sup 2+} at concentration of 10 {mu}M appeared slightly uncoupling (i.e., stimulated resting state respiration and decreased the mitochondrial transmembrane potential), whereas it exerted a strong inhibitory effect on the respiratory chain and rapid dissipation of the membrane potential at higher concentrations. Cu{sup 2+} had inhibitory effect on cell respiration only at 500 {mu}M concentration and after incubation of 48 h but produced a significant uncoupling effect at lower concentrations. Cu{sup 2+} induced an early and sharp increase of intracellular production of reactive oxygen species (ROS). The action of Hg{sup 2+} and Cd{sup 2+} on ROS generation was biphasic. They stimulated ROS generation within the cells at low concentrations and at short incubation times but decreased ROS generation at higher concentrations and at longer incubation. It is concluded that mitochondria are an important target for toxic effects of Hg{sup 2+}, Cd{sup 2+} and Cu{sup 2+} in AS-30D rat hepatoma cells.

  10. Cytoplasmic intron sequence-retaining transcripts can be dendritically targeted via ID element retrotransposons.

    PubMed

    Buckley, Peter T; Lee, Miler T; Sul, Jai-Yoon; Miyashiro, Kevin Y; Bell, Thomas J; Fisher, Stephen A; Kim, Junhyong; Eberwine, James

    2011-03-10

    RNA precursors give rise to mRNA after splicing of intronic sequences traditionally thought to occur in the nucleus. Here, we show that intron sequences are retained in a number of dendritically-targeted mRNAs, by using microarray and Illumina sequencing of isolated dendritic mRNA as well as in situ hybridization. Many of the retained introns contain ID elements, a class of SINE retrotransposon. A portion of these SINEs confers dendritic targeting to exogenous and endogenous transcripts showing the necessity of ID-mediated mechanisms for the targeting of different transcripts to dendrites. ID elements are capable of selectively altering the distribution of endogenous proteins, providing a link between intronic SINEs and protein function. As such, the ID element represents a common dendritic targeting element found across multiple RNAs. Retention of intronic sequence is a more general phenomenon than previously thought and plays a functional role in the biology of the neuron, partly mediated by co-opted repetitive sequences.

  11. Measurements of Ultra-Heavy Elements in Solar Energetic Particle Events Above 10 MeV/nucleon

    NASA Astrophysics Data System (ADS)

    Leske, R. A.; Cohen, C. M.; Cummings, A. C.; Mewaldt, R. A.; Stone, E. C.; Wiedenbeck, M. E.; von Rosenvinge, T. T.

    2005-12-01

    Recent measurements from Wind/LEMT and ACE/ULEIS show that abundances of elements heavier than Ni (Z=28) can be enhanced relative to oxygen by factors of ~100 to 1000 (depending on species) in impulsive solar energetic particle (SEP) events at energies below several MeV/nucleon. The Solar Isotope Spectrometer (SIS) on ACE measures the composition of energetic nuclei for elements up to ~Zr (Z=40) at energies from ~10 to >100 MeV/nucleon. At these energies, even large gradual events often are very iron rich and may appear similar in composition to impulsive events, perhaps due to admixtures of flare seed material. Since August 1997, SIS has recorded ~1000 nuclei with Z≥29, including measurable quantities of Zn, Ge and Se (Z=30, 32, and 34). We present observations that establish the potential of extending ultra-heavy SEP measurements up to higher energies in order to test models of acceleration and abundance enhancements in both gradual and impulsive events. We find that the long-term average composition for elements from Z=30 to 40 appears to be similar to standard solar system values above 10 MeV/nucleon, but that there is considerable event-to-event variability. In particular, the event of 23 July 2004 is found to have very large enhancements in ultra-heavy ions at energies >10 MeV/nucleon, with a (34

  12. Multiple positive and negative 5' regulatory elements control the cell-type-specific expression of the embryonic skeletal myosin heavy-chain gene.

    PubMed Central

    Bouvagnet, P F; Strehler, E E; White, G E; Strehler-Page, M A; Nadal-Ginard, B; Mahdavi, V

    1987-01-01

    To identify the DNA sequences that regulate the expression of the sarcomeric myosin heavy-chain (MHC) genes in muscle cells, a series of deletion constructs of the rat embryonic MHC gene was assayed for transient expression after introduction into myogenic and nonmyogenic cells. The sequences in 1.4 kilobases of 5'-flanking DNA were found to be sufficient to direct expression of the MHC gene constructs in a tissue-specific manner (i.e., in differentiated muscle cells but not in undifferentiated muscle and nonmuscle cells). Three main distinct regulatory domains have been identified: (i) the upstream sequences from positions -1413 to -174, which determine the level of expression of the MHC gene and are constituted of three positive regulatory elements and two negative ones; (ii) a muscle-specific regulatory element from positions -173 to -142, which restricts the expression of the MHC gene to muscle cells; and (iii) the promoter region, downstream from position -102, which directs transcription initiation. Introduction of the simian virus 40 enhancer into constructs where subportions of or all of the upstream sequences are deleted (up to position -173) strongly increases the level of expression of such truncated constructs but without changing their muscle specificity. These upstream sequences, which can be substituted for by the simian virus 40 enhancer, function in an orientation-, position-, and promoter-dependent fashion. The muscle-specific element is also promoter specific but does not support efficient expression of the MHC gene. The MHC promoter in itself is not muscle specific. These results underline the importance of the concerted action of multiple regulatory elements that are likely to represent targets for DNA-binding-regulatory proteins. Images PMID:2830491

  13. Bacterial repetitive extragenic palindromic sequences are DNA targets for Insertion Sequence elements

    PubMed Central

    Tobes, Raquel; Pareja, Eduardo

    2006-01-01

    Background Mobile elements are involved in genomic rearrangements and virulence acquisition, and hence, are important elements in bacterial genome evolution. The insertion of some specific Insertion Sequences had been associated with repetitive extragenic palindromic (REP) elements. Considering that there are a sufficient number of available genomes with described REPs, and exploiting the advantage of the traceability of transposition events in genomes, we decided to exhaustively analyze the relationship between REP sequences and mobile elements. Results This global multigenome study highlights the importance of repetitive extragenic palindromic elements as target sequences for transposases. The study is based on the analysis of the DNA regions surrounding the 981 instances of Insertion Sequence elements with respect to the positioning of REP sequences in the 19 available annotated microbial genomes corresponding to species of bacteria with reported REP sequences. This analysis has allowed the detection of the specific insertion into REP sequences for ISPsy8 in Pseudomonas syringae DC3000, ISPa11 in P. aeruginosa PA01, ISPpu9 and ISPpu10 in P. putida KT2440, and ISRm22 and ISRm19 in Sinorhizobium meliloti 1021 genome. Preference for insertion in extragenic spaces with REP sequences has also been detected for ISPsy7 in P. syringae DC3000, ISRm5 in S. meliloti and ISNm1106 in Neisseria meningitidis MC58 and Z2491 genomes. Probably, the association with REP elements that we have detected analyzing genomes is only the tip of the iceberg, and this association could be even more frequent in natural isolates. Conclusion Our findings characterize REP elements as hot spots for transposition and reinforce the relationship between REP sequences and genomic plasticity mediated by mobile elements. In addition, this study defines a subset of REP-recognizer transposases with high target selectivity that can be useful in the development of new tools for genome manipulation. PMID

  14. THE SuperTIGER Instrument: Measurement of Elemental Abundances of Ultra-Heavy Galactic Cosmic Rays

    NASA Technical Reports Server (NTRS)

    Binns, W. R.; Bose, R. G.; Braun, D. L.; Brandt, T. J.; Daniels, W. M.; DowKonnt, P. F.; Fitzsimmons, S. P.; Hahne, D. J.; Hams, T.; Israel, M. H.; hide

    2014-01-01

    The SuperTIGER (Super Trans-Iron Galactic Element Recorder) instrument was developed to measure the abundances of galactic cosmic-ray elements from Ne-10 to Zr-40 with individual element resolution and the high statistics needed to test models of cosmic-ray origins. SuperTIGER also makes exploratory measurements of the abundances of elements with 40 < Z < or = 60 and measures the energy spectra of the more abundant elements for Z < or = 30 from about 0.8 to 10 GeV/nucleon. This instrument is an enlarged and higher resolution version of the earlier TIGER instrument. It was designed to provide the largest geometric acceptance possible and to reach as high an altitude as possible, flying on a standard long-duration 1.11 million cu m balloon. SuperTIGER was launched from Williams Field, McMurdo Station, Antarctica, on 2012 December 8, and made about 2.7 revolutions around the South Pole in 55 days of flight, returning data on over 50 x 10(exp 6) cosmic-ray nuclei with Z > or = 10, including approx.1300 with Z > 29 and approx.60 with Z > 49. Here, we describe the instrument, the methods of charge identification employed, the SuperTIGER balloon flight, and the instrument performance.

  15. The superTIGER instrument: Measurement of elemental abundances of ultra-heavy galactic cosmic rays

    SciTech Connect

    Binns, W. R.; Bose, R. G.; Braun, D. L.; Dowkontt, P. F.; Israel, M. H.; Moore, P.; Murphy, R. P.; Olevitch, M. A.; Rauch, B. F.; Brandt, T. J.; Daniels, W. M.; Fitzsimmons, S. P.; Hahne, D. J.; Hams, T.; Link, J. T.; Mitchell, J. W.; Sakai, K.; and others

    2014-06-10

    The SuperTIGER (Super Trans-Iron Galactic Element Recorder) instrument was developed to measure the abundances of galactic cosmic-ray elements from {sub 10}Ne to {sub 40}Zr with individual element resolution and the high statistics needed to test models of cosmic-ray origins. SuperTIGER also makes exploratory measurements of the abundances of elements with 40 < Z ≤ 60 and measures the energy spectra of the more abundant elements for Z ≤ 30 from about 0.8 to 10 GeV/nucleon. This instrument is an enlarged and higher resolution version of the earlier TIGER instrument. It was designed to provide the largest geometric acceptance possible and to reach as high an altitude as possible, flying on a standard long-duration 1.11 million m{sup 3} balloon. SuperTIGER was launched from Williams Field, McMurdo Station, Antarctica, on 2012 December 8, and made about 2.7 revolutions around the South Pole in 55 days of flight, returning data on over 50 × 10{sup 6} cosmic-ray nuclei with Z ≥ 10, including ∼1300 with Z > 29 and ∼60 with Z > 49. Here, we describe the instrument, the methods of charge identification employed, the SuperTIGER balloon flight, and the instrument performance.

  16. The SUPERTIGER Instrument: Measurement of Elemental Abundances of Ultra-Heavy Galactic Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Binns, W. R.; Bose, R. G.; Braun, D. L.; Brandt, T. J.; Daniels, W. M.; Dowkontt, P. F.; Fitzsimmons, S. P.; Hahne, D. J.; Hams, T.; Israel, M. H.; Klemic, J.; Labrador, A. W.; Link, J. T.; Mewaldt, R. A.; Mitchell, J. W.; Moore, P.; Murphy, R. P.; Olevitch, M. A.; Rauch, B. F.; Sakai, K.; San Sebastian, F.; Sasaki, M.; Simburger, G. E.; Stone, E. C.; Waddington, C. J.; Ward, J. E.; Wiedenbeck, M. E.

    2014-06-01

    The SuperTIGER (Super Trans-Iron Galactic Element Recorder) instrument was developed to measure the abundances of galactic cosmic-ray elements from 10Ne to 40Zr with individual element resolution and the high statistics needed to test models of cosmic-ray origins. SuperTIGER also makes exploratory measurements of the abundances of elements with 40 < Z <= 60 and measures the energy spectra of the more abundant elements for Z <= 30 from about 0.8 to 10 GeV/nucleon. This instrument is an enlarged and higher resolution version of the earlier TIGER instrument. It was designed to provide the largest geometric acceptance possible and to reach as high an altitude as possible, flying on a standard long-duration 1.11 million m3 balloon. SuperTIGER was launched from Williams Field, McMurdo Station, Antarctica, on 2012 December 8, and made about 2.7 revolutions around the South Pole in 55 days of flight, returning data on over 50 × 106 cosmic-ray nuclei with Z >= 10, including ~1300 with Z > 29 and ~60 with Z > 49. Here, we describe the instrument, the methods of charge identification employed, the SuperTIGER balloon flight, and the instrument performance.

  17. Glann Seaborg's Contributions to Heavy Element Science and the Periodic Table

    SciTech Connect

    Hobart, David E.

    2012-08-17

    In celebrating the centennial anniversary of the birth of Glenn T. Seaborg it is fitting that we recount and pay tribute to his legacy. Many know of the scientific accomplishments of this man who became a legend and anyone who has attended his lectures can attest to how informative, educational, and entertaining he was. He had a beguiling and whimsical sense of humor and used this to drive home his points and share his passion and quest for discovery. The periodic table is a fundamental cornerstone of science and remains a central unifying principal. Seaborg was the architect of the actinide series of elements and their proper placement in the periodic table and co-discoverer of ten transuranium elements - one of which bears his name, element 106, seaborgium. The work and achievements of this Nobel laureate have touched the lives of many and his legacy will continue for generations to come.

  18. A comprehensive analysis of the content of heavy rare-earth elements and platinum in snow samples to assess the ecological hazard of air pollution in urban areas

    NASA Astrophysics Data System (ADS)

    Vinokurov, S. F.; Tarasova, N. P.; Trunova, A. N.; Sychkova, V. A.

    2017-07-01

    Snow samples from the territory of the Setun River Valley Wildlife Sanctuary are analyzed for the content of rare-earth elements, heavy metals, and other hazardous elements by the inductively coupled plasma mass-spectrometry method. The changes in the concentrations of rare-earth elements, Pt, Pd, and indicator ratios of elements in the solid fractions of snow are revealed. A trend toward a decrease in the content of several elements northeastward of the Moscow Ring Road (MRR) is established. The level of seasonal atmospheric contamination of the area under study is assessed, and a possible source is identified.

  19. The correlation of serum trace elements and heavy metals with carotid artery atherosclerosis in maintenance hemodialysis patients.

    PubMed

    Ari, Elif; Kaya, Yuksel; Demir, Halit; Asicioglu, Ebru; Keskin, Sıddık

    2011-12-01

    Changes in essential trace elements and heavy metals may affect the atherosclerotic state of patients on maintenance hemodialysis (HD). The aim of the study was to evaluate the relation between the serum levels of some trace elements and heavy metals (iron, zinc, manganese, copper, magnesium, cobalt, cadmium, lead, and copper/zinc ratio) and carotid artery intima-media thickness (CIMT) in HD patients. Fifty chronic HD patients without known atherosclerotic disease and 48 age- and sex-matched healthy individuals were included in the study. The serum levels of trace elements (iron, zinc, manganese, copper, and magnesium) and heavy metals (cobalt, cadmium, and lead) were measured by Atomic Adsorption Spectrophotometer (UNICAM-929). CIMT was assessed by carotid artery ultrasonography. The serum levels of iron, zinc, and manganese were lower; levels of copper, magnesium, cobalt, cadmium, lead, and copper/zinc ratio were higher in HD patients compared to controls. CIMT in HD patients were higher than the control group (0.64 ± 0.11 vs 0.42 ± 0.05, p < 0.001). There was a significant negative correlation between CIMT and serum levels of zinc (r = -0.70, p < 0.01), iron (r = -0.71, p < 0.01), and manganese (r = -0.47, p < 0.01), while there was a significant positive correlation between CIMT and serum levels of copper (r = 0.63, p < 0.01), magnesium (r = 0.77, p < 0.01), cobalt (r = 0.63, p < 0.01), cadmium (r = 0.48, p < 0.01), lead (r = 0.38, p < 0.01), and copper/zinc ratio (r = 0.68, p < 0.01). A linear regression analysis showed that serum levels of magnesium, cadmium, lead, and copper/zinc ratio were still significantly and positively correlated with CIMT. We propose that copper/zinc ratio, magnesium and toxic metals cadmium and lead are independent determinants of CIMT in maintenance HD patients without known atherosclerotic disease.

  20. A procedure to correct for target thickness effects in heavy-ion PIXE at MeV energies

    NASA Astrophysics Data System (ADS)

    Zucchiatti, Alessandro; Galán, Patricia; Prieto, José Emilio

    2017-09-01

    We describe a novel procedure for the calculation of correction factors for taking into account the effect of target thickness to be applied to the determination of cross sections of X-ray emission induced by heavy ions at MeV energies. We discuss the origin of the correction and describe the calculations, based on simple polynomial fits of both the theoretical cross sections and the ion energy losses. The procedure can be easily implemented. We show several examples for a set of targets specifically produced for cross section measurements and for various combinations of ion type and energy.

  1. Quantum Monte Carlo of atomic and molecular systems with heavy elements

    NASA Astrophysics Data System (ADS)

    Mitas, Lubos; Kulahlioglu, Adem; Melton, Cody; Bennett, Chandler

    2015-03-01

    We carry out quantum Monte Carlo calculations of atomic and molecular systems with several heavy atoms such as Mo, W and Bi. In particular, we compare the correlation energies vs their lighter counterparts in the same column of the periodic table in order to reveal trends with regard to the atomic number Z. One of the observations is that the correlation energy for the isoelectronic valence space/states is mildly decreasing with increasing Z. Similar observation applies also to the fixed-node errors, supporting thus our recent observation that the fixed-node error increases with electronic density for the same (or similar) complexity of the wave function and bonding. In addition, for Bi systems we study the impact of the spin-orbit on the electronic structure, in particular, on binding, correlation and excitation energies.

  2. Multiple DNA sequence elements are necessary for the function of an immunoglobulin heavy chain promoter.

    PubMed Central

    Eaton, S; Calame, K

    1987-01-01

    Sequences required for the function of the mouse V1 immunoglobulin heavy chain variable-region (VH) promoter were identified by transient transfection of the normal and mutated promoters into plasmacytoma cells. Our results identify four regions required for normal promoter function: (i) the octamer ATGCAAAT, previously identified by others; (ii) a heptamer, CTAATGA; (iii) a pyrimidine-rich region; and (iv) a region between positions -125 and -251 relative to the transcription start site. Sequence analysis of 19 mouse and human VH 5' flanking regions shows that the heptamer and pyrimidine stretch are strongly conserved. We have also demonstrated that the octamer functions in an orientation independent manner in the VH promoter. Images PMID:3118372

  3. Lead, platinum, and other heavy elements in the primary cosmic radiation - HEAO 3 results

    NASA Technical Reports Server (NTRS)

    Binns, W. R.; Israel, M. H.; Brewster, N. R.; Fixsen, D. J.; Garrard, T. L.

    1985-01-01

    An observation of the abundances of cosmic-ray lead-group and platinum-group nuclei is reported, using data from the HEAO 3 Heavy Nuclei Experiment. From an analysis of 580 days of exposure, 322 nuclei were selected with reasonable charge resolution, E at least 1.3 GeV/nucleon and Z at least 50. The data show a defined abundance peak in the 'platinum' region (Z from 74 to 80), a small abundance of 'lead' (Z from 81 to 83), and a significant number of 'secondary' nuclei in the range of Z between 62 and 73. Possible explanations are offered for the deduced ratio in space of 0.25 plus or minus 0.09 for 'Pb/Pt' being distinctly lower than that predicted by any of the standard models for cosmic-ray sources and propagation effects.

  4. Lead, platinum, and other heavy elements in the primary cosmic radiation - HEAO 3 results

    NASA Technical Reports Server (NTRS)

    Binns, W. R.; Israel, M. H.; Brewster, N. R.; Fixsen, D. J.; Garrard, T. L.

    1985-01-01

    An observation of the abundances of cosmic-ray lead-group and platinum-group nuclei is reported, using data from the HEAO 3 Heavy Nuclei Experiment. From an analysis of 580 days of exposure, 322 nuclei were selected with reasonable charge resolution, E at least 1.3 GeV/nucleon and Z at least 50. The data show a defined abundance peak in the 'platinum' region (Z from 74 to 80), a small abundance of 'lead' (Z from 81 to 83), and a significant number of 'secondary' nuclei in the range of Z between 62 and 73. Possible explanations are offered for the deduced ratio in space of 0.25 plus or minus 0.09 for 'Pb/Pt' being distinctly lower than that predicted by any of the standard models for cosmic-ray sources and propagation effects.

  5. Multiple DNA sequence elements are necessary for the function of an immunoglobulin heavy chain promoter

    SciTech Connect

    Eaton, S.; Calame, K.

    1987-11-01

    Sequences required for the function of the mouse V1 immunoglobulin heavy chain variable-region (V/sub H/) promoter were identified by transient transfection of the normal and mutated promoters into plasmacytoma cells. The results identify four regions required for normal promoter function: (i) the octamer ATGCAAAT, previously identified by others; (ii) a heptamer, CTAATGA; (iii) a pyrimidine-rich region; and (iv) a region between positions -125 and -251 relative to the transcription start site. Sequence analysis of 19 mouse and human V/sub H/ 5' flanking regions shows that the heptamer and pyrimidine stretch are strongly conserved. The authors have also demonstrated that the octamer functions in an orientation independent manner in the V/sub H/ promoter.

  6. Fixation and imaging of biological elements: heavy metals, diffusible substances, ions, peptides, and lipids.

    PubMed

    Mizuhira, V; Hasegawa, H; Notoya, M

    2000-01-01

    We tested various fixation and analysis methods to demonstrate by electron microscopy elemental imaging in tissues and cells, i.e., soluble substances such as many kinds of ionic elements, water soluble low molecular peptides, and even organic solvent soluble substances such as lipids. For the ionic elements, we tested frozen dried or freeze-substituted methods and organic or inorganic special chemical precipitation methods combined with microwaved fixation methods. The data were analyzed with electron beam X-ray microanalysis, electron energy filtered imaging analysis, and electron microscope autoradiography. The data were demonstrated as elemental distribution images and were calculated quantitatively. For the soluble low molecular peptides, we developed a tannic acid and aldehyde method combined with microwaved fixation. We discuss the theoretical background of the tannic acid fixation and microwaved fixation methods. For the organic solvent soluble substances, i.e., lipids including steroids, we successfully tested the use of a mixed fixative of aldehyde and osmium, digitonization, and osmification with the use of p-phenylendiamine or imidazole. We also proposed some new ideal biotracers for electron beam X-ray microanalysis and electron energy filtered imaging analysis.

  7. Combined element magnet production for the relativistic heavy ion collider (RHIC) at BNL

    SciTech Connect

    Mulhall, S.; Foelsche, H.; Ganetis, G.

    1995-05-01

    The production of 432 combined element magnets for RHIC is well underway. These magnets consist of a superconducting corrector, a quadrupole, and a sextupole combined into an integrated cold mass which is inserted into a cryostat. Production experiences as well as test results are reported.

  8. Study of heavy metals and other elements in macrophyte algae using energy-dispersive X-ray fluorescence

    SciTech Connect

    Carvalho, M.L.; Amorim, P.; Marques, M.I.M.; Ramos, M.T.; Ferreira, J.G.

    1997-04-01

    Fucus vesiculosus L. seaweeds from three estuarine stations were analyzed by X-ray fluorescence, providing results for the concentration of total K, Ca, Ti, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Sr, and Pb. Four different structures of the algae (base, stipe, reproductive organs, and growing tips) were analyzed to study the differential accumulation of heavy metals by different parts of Fucus. Some elements (e.g., Cu and Fe) are preferentially accumulated in the base of the algae, whereas others (e.g., As) exhibit higher concentrations in the reproductive organs and growing tips. The pattern of accumulation in different structures is similar for Cu, Zn, and Pb, but for other metals there is considerable variability in accumulation between parts of the plant. This is important in determining which structures of the plant should be used for biomonitoring. For samples collected at stations subject to differing metal loads, the relative elemental composition is approximately constant, notwithstanding significant variation in absolute values. The proportion of metals in Fucus is similar to that found in other estuaries, where metal concentrations are significantly lower. Energy-dispersive X-ray fluorescence has been shown to be a suitable technique for multielement analysis in this type of sample. No chemical pretreatment is required, minimizing sample contamination. The small amount of sample required, and the wide range of elements that can be detected simultaneously make energy-dispersive X-ray fluorescence a valuable tool for pollution studies.

  9. Application of prestressed structural elements in the erection of heavy viscoelastic arched structures with the use of an additive technology

    NASA Astrophysics Data System (ADS)

    Manzhirov, A. V.; Parshin, D. A.

    2016-11-01

    The process of erection an object under the action of gravity forces in the absence of additional loads is studied together with the technology of application of prestressed structure elements. The mathematically two-dimensional engineering problem of mechanics of gradual building of a heavy semicircular vault from a prestressed viscoelastic homogeneously aging material is solved analytically. The vault fixation on a rigid horizontal base by sliding fixation, which ensures continuous smooth contact between the vault foot and the base, is considered. The performed computations permit demonstrating high efficiency of preliminary stress creation in the material elements added to the vault in the process of its building in order to control its technological stress state. It is shown that this measure permits significantly decreasing the final values of the separating contact stresses on the foot of the built vault and obtaining the final state of the whole structure which is safer with respect to the level of tensile stresses than that obtain by using unstressed elements.

  10. Natural radioactive elements and heavy metals in coal, fly ash and bottom ash from a thermal power plant

    SciTech Connect

    Font, J.; Casas, M.; Forteza, R.; Cerda, V.; Garcias, F. )

    1993-11-01

    The composition of coal used as fuel at a thermal power plant and those of the fly and bottom ashes it produces were determined. Radioactive elements were analysed for by alpha and gamma spectrometry, while sulphur, carbon and nitrogen were determined by burning. Heavy metals were quantified by X-ray fluorescence spectrometry and inductively coupled plasma atomic emission spectroscopy (ICPAES). The low sulphur content of the coal (0.68%) gives rise to fly ash containing only 0.21% of this element. The radiochemical analyses performed by alpha spectrometry revealed that most of the uranium remains in the solid residue resulting from disaggregation of the sample with Na[sub 2]CO[sub 3] in the separation process. Also, the gamma spectrometric results show that the elements from the 4n and 4n + 2 series and [sup 40]K concentrate in fly ash, the mean particle size of which is the smallest of all the residues assayed. 8 refs., 5 figs., 5 tabs.

  11. Transgenic analysis of the thyroid-responsive elements in the alpha-cardiac myosin heavy chain gene promoter.

    PubMed

    Subramaniam, A; Gulick, J; Neumann, J; Knotts, S; Robbins, J

    1993-02-25

    The role of two putative, cis-acting thyroid hormone-responsive elements, TRE1 and TRE2, located at -129 to -149 and -102 to -120, respectively, on the murine alpha-myosin heavy chain (MHC) gene, has been investigated in transgenic mice. These motifs are present in a 4.5-kilobase fragment lying upstream of the transcriptional start site of the mouse alpha-MHC gene: this fragment directs appropriate expression of a reporter gene in transgenic mice (Subramaniam, A., Jones, W. K., Gulick, J., Wert, S., Neumann, J., and Robbins, J. (1991) J. Biol. Chem. 266, 24613-24620). Here, we independently mutate the TRE1 and TRE2 elements by base substitution. The mice were analyzed for transgene expression in different muscle and non-muscle tissues including the atria and ventricles. Normal levels of transgene expression were observed in euthyroid mice carrying a mutation in TRE1. In contrast to these results, mice in which TRE2 was mutated showed reduced levels of CAT activity in both the atria and ventricles, suggesting a previously undefined role for this element in the constitutive up-regulation of the alpha-MHC gene. In hypothyroid mice carrying either of these mutations, the complete cessation of ventricular expression of the chloramphenicol acetyltransferase transcripts that takes place in the alpha-5.5 (wild type) animals did not occur.

  12. Quantitative analysis of some oligo-elements and heavy metals in some species of Thymus from Morocco.

    PubMed

    Bennouna, M A; Belaqziz, R; Arjouni, M Y; Romane, A

    2013-01-01

    In order to valorise natural substances, concentrations of 20 mineral elements were evaluated in five species of Moroccan thyme. These species which belong to the Lamiaceae family are Thymus leptobotrys, Thymus broussonetii, Thymus maroccanus, Thymus pallidus and Thymus satureioïdes growing in different regions of central and southern Morocco. Samples of plants were subjected to digestion and heavy metals were determined by inductively coupled plasma mass spectrometry. The highest concentrations of calcium, iron, zinc, cobalt and chromium were registered in T. broussonetii, T. pallidus, T. leptobotrys, T. maroccanus and T. satureioïdes with respective values of 1991, 423, 73, 6 and 11 mg/kg. Furthermore, silicium and boron were analysed only for the species T. broussonetii and their respective concentrations were found to be 112 and 43 mg/kg. The ultra trace elements Si, B, Ni, Ni, As, Li, V and toxic elements Cd and Pb were also evaluated. The results were treated by the method of principal components analysis.

  13. Ultrashort pulsed laser tools for testing of semiconductor elements hardness to single event effects, caused by cosmic heavy charged particles

    NASA Astrophysics Data System (ADS)

    Gordienko, Alexandra V.; Mavritskii, Oleg B.; Egorov, Andrey N.; Pechenkin, Alexander A.; Savchenkov, Dmitriy V.

    2015-03-01

    The installations for laser testing of microelectronic elements (first of all - integrated circuits) of devices for space applications for hardness to local radiation effects from heavy charged particles are presented. The possibility of a focused pulsed laser radiation application to the study of local radiation effects, caused by single heavy charged particles, is explained. The fundamentals of an approach to the construction of test sets, based on the picosecond and femtosecond lasers and systems for focusing their radiation, are considered. The main technical requirements for the basic modules of sets for laser testing (laser wavelength and pulse duration and repetition rate, spatial beam parameters and minimal spot size, speed of object movement and so on) are substantiated. All worked out sets have a full-featured software for the operational management of all modules of the laser test facility, including the positioning of the object, to provide feedback from the measurement results of the reaction of the object on the laser excitation. The parameters of developed laser hardware and software systems and their foreign counterparts are compared. Further improvement directions for laser testing tools are briefly outlined. The discussion is also presented of described hardware technical and operational characteristics, allowing to use it for a variety of scientific research studies, requiring selective (with submicron spatial resolution) object excitation by ultrashort laser pulses and recording responses to this effect with the exact timing of the moment of excitation, as well as to perform a variety of high precision technological operations.

  14. Trace elements and heavy metals in the Grand Bay National Estuarine Reserve in the northern Gulf of Mexico

    PubMed Central

    McComb, Jacqueline Q.; Han, Fengxiang X.; Rogers, Christian; Thomas, Catherine; Arslan, Zikri; Ardeshir, Adeli; Tchounwou, Paul B.

    2015-01-01

    The objectives of this study are to investigate distribution of trace elements and heavy metals in the salt marsh and wetland soil and biogeochemical processes in the Grand Bay National Estuarine Research Reserve of the northern Gulf of Mexico. The results show that Hg, Cd and to some extent, As and Pb have been significantly accumulated in soils. The strongest correlations were found between concentrations of Ni and total organic matter contents. The correlations decreased in the order: Ni > Cr > Sr > Co > Zn, Cd > Cu > Cs. Strong correlations were also observed between total P and concentrations of Ni, Co, Cr, Sr, Zn, Cu, and Cd. This may be related to the P spilling accident in 2005 in the Bangs Lake site. Lead isotopic ratios in soils matched well those of North American coals, indicating the contribution of Pb through atmospheric fallout from coal power plants. PMID:26238403

  15. Magnetocaloric effect in heavy rare-earth elements doped Fe-based bulk metallic glasses with tunable Curie temperature

    NASA Astrophysics Data System (ADS)

    Li, Jiawei; Huo, Juntao; Law, Jiayan; Chang, Chuntao; Du, Juan; Man, Qikui; Wang, Xinmin; Li, Run-Wei

    2014-08-01

    The effects of heavy rare earth (RE) additions on the Curie temperature (TC) and magnetocaloric effect of the Fe-RE-B-Nb (RE = Gd, Dy and Ho) bulk metallic glasses were studied. The type of dopping RE element and its concentration can easily tune TC in a large temperature range of 120 K without significantly decreasing the magnetic entropy change (ΔSM) and refrigerant capacity (RC) of the alloys. The observed values of ΔSM and RC of these alloys compare favorably with those of recently reported Fe-based metallic glasses with enhanced RC compared to Gd5Ge1.9Si2Fe0.1. The tunable TC and large glass-forming ability of these RE doped Fe-based bulk metallic glasses can be used in a wide temperature range with the final required shapes.

  16. Trace elements and heavy metals in the Grand Bay National Estuarine Reserve in the northern Gulf of Mexico.

    PubMed

    McComb, Jacqueline Q; Han, Fengxiang X; Rogers, Christian; Thomas, Catherine; Arslan, Zikri; Ardeshir, Adeli; Tchounwou, Paul B

    2015-10-15

    The objectives of this study are to investigate distribution of trace elements and heavy metals in the salt marsh and wetland soil and biogeochemical processes in the Grand Bay National Estuarine Research Reserve of the northern Gulf of Mexico. The results show that Hg, Cd and to some extent, As and Pb have been significantly accumulated in soils. The strongest correlations were found between concentrations of Ni and total organic matter contents. The correlations decreased in the order: Ni>Cr>Sr>Co>Zn, Cd>Cu>Cs. Strong correlations were also observed between total P and concentrations of Ni, Co, Cr, Sr, Zn, Cu, and Cd. This may be related to the P spilling accident in 2005 in the Bangs Lake site. Lead isotopic ratios in soils matched well those of North American coals, indicating the contribution of Pb through atmospheric fallout from coal power plants.

  17. Experimental K X-ray intensity ratios of some heavy elements

    NASA Astrophysics Data System (ADS)

    Sakar, E.; Gurol, A.; Bastug, A.

    2017-02-01

    The K X-ray intensity ratios of some elements (Z&2gt;70) were measured by using an Energy Dispersive X-Ray Fluorescence Spectrometer, which has an intense radioisotope source and an HPGe detector. The experimental results had uncertainties about 4% and were in good agreement with theoretical results of Scofield. In order to obtain more reliable results, the experiments should be carried out with synchrotron radiation having a more intense and monochromatic radiation source and detectors with better resolutions.

  18. Elemental abundance and spectral variations of the suprathermal heavy ion populations in interplanetary space

    NASA Astrophysics Data System (ADS)

    Al Dayeh, Maher Abdul Hamid

    Solar energetic particles (SEPs) associated with coronal mass ejections (CMEs) are usually accompanied by large particle intensities and magnetic clouds that often cause terrestrial geomagnetic storms. These storms present a danger to many aspects on earth, from satellites and communications, to power and pipelines, in addition to forming a danger to astronauts in space. The scientific objectives for studying SEPs in this dissertation are twofold. First is to improve our understanding of SEP sources, acceleration, and propagation in interplanetary (IP) space. The second is to improve our capabilities in space weather prediction. This dissertation investigates the source material of SEPs through detailed analysis of the temporal, compositional, and spectral variations of heavy ion species (mass > 4 nucleons) at the energy range ~0.045 MeV/nuc -10 MeV/nuc from December 1995 to December 2006, thus covering all of solar cycle 23. Data used in this dissertation are mainly from ULEIS and STEP time-of-flight mass spectrometers onboard the ACE (launched 08/1997) and Wind (launched 11/1994) spacecraft respectively. Observations reported in this work show that daily variations of low-energy heavy ions (~0.12 MeV/nucleon) in IP space are correlated with the solar cycle. Such dependence is not seen in a set of gradual SEP events. However, these events show large event-to-event fluctuations. This suggests that there exist multiple scenarios by which the seed material is injected into accelerating IP shocks, these are: (i) remnant material from previous flares that remain in IP space or get continuously replenished by frequent flare activity; (ii) direct contributions from accompanying flares, i.e., particles that escape from the flare through open field lines could encounter the CME shock, get re- accelerated and cause an enhancement in the heavy-ion abundances; (iii) the same or nearby active regions on the Sun produce suprathermal particles with flare-like composition that

  19. What are the astrophysical sites for the r-process and the production of heavy elements?

    NASA Astrophysics Data System (ADS)

    Thielemann, F.-K.; Arcones, A.; Käppeli, R.; Liebendörfer, M.; Rauscher, T.; Winteler, C.; Fröhlich, C.; Dillmann, I.; Fischer, T.; Martinez-Pinedo, G.; Langanke, K.; Farouqi, K.; Kratz, K.-L.; Panov, I.; Korneev, I. K.

    2011-04-01

    This article addresses three of the four nucleosynthesis processes involved in producing heavy nuclei beyond Fe (with a main focus on the r-process). Opposite to the fourth process (the s-process), which operates in stellar evolution during He- and C-burning, they are all related to explosive burning phases, (presumably) linked to core collapse supernova events of massive stars. The (classical) p-process is identified with explosive Ne/O-burning in outer zones of the progenitor star. It is initiated by the passage of the supernova shock wave and acts via photodisintegration reactions like a spallation process which produces neighboring (proton-rich) isotopes from pre-existing heavy nuclei. The reproduction of some of the so-called lighter p-isotopes with A<100 faces problems in this environment. The only recently discovered νp-process is related to the innermost ejecta, the neutrino wind expelled from the hot proto-neutron star after core collapse and the supernova explosion. This neutrino wind is proton-rich in its early phase, producing nuclei up to 64Ge. Reactions with neutrinos permit to overcome decay/reaction bottlenecks for the flow beyond 64Ge, thus producing light p-isotopes, which face problems in the classical p-process scenario. The understanding of the r-process, being identified for a long time with rapid neutron captures and passing through nuclei far from stability, is still experiencing major problems. These are on the one hand related to nuclear uncertainties far from stability (masses, half-lives, fission barriers), affecting the process speed and abundance peaks. On the other hand the site is still not definitely located, yet. (i) Later, possibly neutron-rich, high entropy phases of the neutrino wind (if they materialize!) could permit its operation. (ii) Other options include the ejection of very neutron-rich neutron star-like matter, occurring possibly in neutron star mergers or core collapse supernova events with jets, related to prior

  20. Heavy metals, metalloids and other hazardous elements in marine plastic litter.

    PubMed

    Turner, Andrew

    2016-10-15

    Plastics, foams and ropes collected from beaches in SW England have been analysed for As, Ba, Br, Cd, Cl, Cr, Cu, Hg, Ni, Pb, Sb, Se, Sn and Zn by field-portable-x-ray fluorescence spectrometry. High concentrations of Cl in foams that were not PVC-based were attributed to the presence of chlorinated flame retardants. Likewise, high concentrations of Br among both foams and plastics were attributed to the presence of brominated flame retardants. Regarding heavy metals and metalloids, Cd and Pb were of greatest concern from an environmental perspective. Lead was encountered in plastics, foams and ropes and up to concentrations of 17,500μgg(-1) due to its historical use in stabilisers, colourants and catalysts in the plastics industry. Detectable Cd was restricted to plastics, where its concentration often exceeded 1000μgg(-1); its occurrence is attributed to the use of both Cd-based stabilisers and colourants in a variety of products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Trace elements and heavy metals in mineral and bottled drinking waters on the Iranian market.

    PubMed

    Hadiani, Mohammad Rasoul; Dezfooli-Manesh, Shirin; Shoeibi, Shahram; Ziarati, Parisa; Mousavi Khaneghah, Amin

    2015-01-01

    A survey of Iranian waters, sampled from 2010 to 2013, is presented. A total of 128 water samples from 42 different brands of bottled mineral and drinking water were collected and analysed for contamination levels of lead (Pb), cadmium (Cd), copper (Cu), arsenic (As) and mercury (Hg). Determinations were performed using a graphite furnace atomic absorption spectrophotometer for Pb, Cd and Cu, a hydride vapour generation as well as an Arsenator digital kit (Wagtech WTD, Tyne and Wear, UK) for As and a direct mercury analyser for Hg. Arsenic concentration in six bottled gaseous mineral samples was higher than the related limit. Regardless of these, mean concentrations of Pb, Cd, Cu, As and Hg in all types of water samples were 4.50 ± 0.49, 1.08 ± 0.09, 16.11 ± 2.77, 5.80 ± 1.63 and 0.52 ± 0.03 µg L⁻¹, respectively. Values obtained for analysed heavy metals in all samples were permissible according to the limits of national and international standards.

  2. Interactions of heavy nuclei, Kr, Xe and Ho, in light targets

    NASA Technical Reports Server (NTRS)

    Kertzman, M. P.; Klarmann, J.; Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Garrard, T. L.; Israel, M. H.

    1985-01-01

    Over the past few years, the HEAO-3 measurements of the abundance of ultra-heavy cosmic ray nuclei (Z 26) at Earth were analyzed. In order to interpret these abundances in terms of a source composition, allowances must be made for the propagation of the nuclei in the interstellar medium. Vital to any calculation of the propagation is a knowlege of the total and partial interaction cross sections for these heavy nuclei on hydrogen. Until recently, data on such reactions have been scarce. The semi-empirical formalism of Silberberg and Tsao were relied upon to predict the partial cross sections. However, now that relativistic heavy ion beams are available at the LBL Bevalac, some of the cross sections of interest can be measured at energies close to those of the cosmic ray nuclei being observed.

  3. Maps showing interpretation, using R-mode factor analysis, of trace-element abundances in heavy-mineral concentrate samples, Delta 1° x 2° Quadrangle, Utah

    USGS Publications Warehouse

    Zimbelman, David R.

    1994-01-01

    A set of heavy-mineral concentrate data for the Delta 1° x 2° quadrangle, Utah Conterminous U.S. Mineral Assessment Program (CUSMAP) project was compiled from results of analyses of samples collected during the National Uranium Resource Evaluation Program (SURE), as well as results obtained from samples collected more recently by the USGS. Data results, sampling methods, and analytical methods are provided in Abrogast and others, 1993; 1990; 1988a; 1988b). A similar report, discussing results obtained from stream-sediment samples, is presented in Zimbelman (1993a). The Delta 1° x 2° quadrangle, Utah (figure 1) contains a variety of hydrothermal mineral deposit types, including porphyry-, vein-, replacement-, and Carlin-type deposits. These deposit types have been worked for commodities including gold, silver, beryllium, uranium, lead, zinc, copper, manganese, and cadmium (Lindsey, 1977; Morris and Mogensen, 1978; Zimbelman and others, 1990; Zimbelman and others, 1988). Heavy-mineral concentrate and stream-sediment samples derived from these hydrothermally altered rocks typically contain many geochemical anomalies (for example, see Zimbelman 1993b, c, d). Element associations characterizing lithology and hydrothermal mineral deposits can be distinguished using R-mode factor analysis. This tool often is useful in reconnaissance-scale surveys where sample anomalies are often weak. and single-element distributions may not help to delineate targets. R-mode factors analysis can help identify geologic trends and areas most likely to contain the mineral deposits. R-mode factor analysis was performed on a data set of results of analyses for 19 elements in 643 samples and produced a six-factor model. These six factors represent the geochemical contributions to the data set provided by lithologic and mineralization processes, The distribution of samples that contain high scores for mineralization-related factors is widespread in the Delta quadrangle. These sample sites

  4. Targeting heterochromatin formation to transposable elements in Drosophila: potential roles of the piRNA system.

    PubMed

    Sentmanat, M; Wang, S H; Elgin, S C R

    2013-06-01

    Successful heterochromatin formation is critical for genome stability in eukaryotes, both to maintain structures needed for mitosis and meiosis and to silence potentially harmful transposable elements. Conversely, inappropriate heterochromatin assembly can lead to inappropriate silencing and other deleterious effects. Hence targeting heterochromatin assembly to appropriate regions of the genome is of utmost importance. Here we focus on heterochromatin assembly in Drosophila melanogaster, the model organism in which variegation, or cell-to-cell variable gene expression resulting from heterochromatin formation, was first described. In particular, we review the potential role of transposable elements as genetic determinants of the chromatin state and examine how small RNA pathways may participate in the process of targeted heterochromatin formation.

  5. Micro-distribution of heavy rare earth elements in Round Top Mountain rhyolite deposit (Hudspeth County, Texas, USA) by EPMA mapping

    NASA Astrophysics Data System (ADS)

    Pingitore, N. E., Jr.; Piranian, M.; Amaya, M. A.; Negron, L. M.; Gorski, D.

    2015-12-01

    Round Top Mountain, west Texas, USA, is composed almost entirely of peraluminous rhyolite, with pervasive low-grade enrichment in yttrium and heavy rare earth elements (Y+HREEs). The exposed rhyolite laccolith also contains Li, Be, U, Th, Nb, Ta, Ga, Rb, Cs, Sn, and F. The valuable Y+HREEs are hosted in yttrofluorite, which is soluble in dilute sulfuric acid. Texas Rare Earth Resources, Inc. proposes to surface mine, crush, and heap leach the massive, 109ton deposit. The distribution of Y+HREEs, and that of other trace elements, is remarkably homogeneous at outcrop drill hole scale (Pingitore et al., FM14-V23D-4827: Uniform Distribution of Yttrium…). Here we document that Y+HREE mineralization appears pervasive through the rhyolite at a sub-millimeter scale. We examined 15 thin sections of rhyolite fragments randomly selected from a composite sample produced by mixing several hundred kg of aliquot material recovered from >100 reverse circulation drill holes scattered across much of the mountain. A total of 16 elements (Y, Dy, Yb, F, U, Th, Nb, Sn, Zr, Rb, Ca, Na, K, Fe, Al, Si) plus back scattered electron image were mapped in WDS mode by stage raster across a 2 x 2 mm field at 516 x 516 pixel resolution on a Cameca SX-100 class EPMA. Typical maps revealed 5-10 grains that contained Y + Dy + Yb; most also contained F and Ca, indicating yttrofluorite mineralogy. Most grains were under 10 μm in 2-D size. We view this 5-10 grain figure of merit as a minimum number of target grains since we employed a conservative approach to their identification. This finding suggests that a 1 mm cube of the rhyolite contains 250-500 target grains (assuming that the EPMA sampled to a depth of 5 μm and that sampled grains did not extend below that depth in size). Viewed from a mining processing standpoint, each particle for the anticipated heap leach, with a nominal crush size of ½ to 1 inch (13-26 mm), would contain on the order of 250,000 to 500,000 target microscopic mineral

  6. Abundances of heavy elements in metal deficient stars II. Detailed spectroscopic analysis

    NASA Astrophysics Data System (ADS)

    Zhao, Gang

    1994-01-01

    In this paper, we determine the abundances of a number of neutron capture elements in metal-poor dwarfs and subgiants. The strontium, yttrium, zirconium, barium, lanthanum, cerium and europium abundances are deduced in a sample of 10 to 20 stars on the basis of high resolution, high signal-to-noise spectra. The main results are: (1) The elements of the first peak, strontium-yttrium-zirconium, show the odd-even effect: strontium and zirconium are less deficient than yttrium in Population II stars. (2) The yttrium abundance is constant ([ Y/Fe] = -0.06) for all stars with [ Fe/H] > -2.5 . (3) The barium overdeficiency increases with decreasing metallicity when [ Fe/H] < -1.7 . (4) Lanthanum and cerium are overdeficient with respect to iron. (5) Europium is overabundant for -1 > [ Fe/H] > -2 . (6) There is a real cosmic scatter in [ Y/Fe] , [ Zr/Fe] and [ Ba/Fe] , of the order of 0.1 dex.

  7. Heavy metals and mineral elements not included on the nutritional labels in table olives.

    PubMed

    López-López, Antonio; López, Rafael; Madrid, Fernando; Garrido-Fernández, Antonio

    2008-10-22

    The average contents, in mg/kg edible portion (e.p.), of elements not considered for nutritional labeling in Spanish table olives were as follows: aluminum, 71.1; boron, 4.41; barium, 2.77; cadmium, 0.04; cobalt, 0.12; chromium, 0.19; lithium, 6.56; nickel, 0.15; lead, 0.15; sulfur, 321; tin, 18.4; strontium, 9.71; and zirconium, 0.04. Sulfur was the most abundant element in table olives, followed by aluminum and tin (related to green olives). There were significant differences between elaboration styles, except for aluminum, tin, and sulfur. Ripe olives had significantly higher concentrations (mg/kg e.p.) of boron (5.32), barium (3.91), cadmium (0.065), cobalt (0.190), chromium (0.256), lithium (10.01), nickel (0.220), and strontium (10.21), but the levels of tin (25.55) and zirconium (0.039) were higher in green olives. The content of contaminants (cadmium, nickel, and tin) was always below the maximum limits legally established. The discriminant analysis led to an overall 86% correct classification of cases (80% after cross-validation).

  8. Heavy metal transfers between trophic compartments in different ecosystems in Galicia (Northwest Spain): Essential elements

    SciTech Connect

    Gonzalez, X.I.; Aboal, J.R.; Fernandez, J.A.; Carballeira, A.

    2008-11-15

    In the present study, we determined the concentrations of Cu, Fe, Mn, and Zn in soil and several trophic compartments at a total of 16 sampling stations. The trophic compartments studied were primary producers, represented by two species of terrestrial mosses (Pseudoescleropodium purum and Hypnum cupressiforme) and oak trees (Quercus robur or Q. pyrenaica); primary consumers, represented by the wood mouse (Apodemus sylvaticus) and the yellow necked mouse (A. flavicollis); secondary consumers, represented by the shrew (Sorex granarius); and finally, detritivores, represented by slugs (Arion ater). Thirteen of the sampling stations were located in mature oak woodlands (Quercus sp.); two of the sampling stations were located in the area surrounding a restored lignite mine dump, and the other in an ultrabasic area. The analytical determinations revealed a lack of significant correlations among trophic compartments, possibly caused by effective regulation of metals by organisms and/or spatial variation in availability of metals from soil or food. Furthermore, the only element that showed a clear pattern of biomagnification was Cu; as for the other elements, there was always some divergence from such a pattern. Finally, the patterns of bioaccumulation in contaminated and woodland sampling stations were very similar, although there was enrichment of the concentrations of Cu, Mn, and Zn in the mice viscera, which, except for Mn, were related to higher edaphic concentrations.

  9. RCS Predictions From a Method of Moments and a Finite-Element Code for Several Targets

    DTIC Science & Technology

    2010-07-01

    01803 14. ABSTRACT This report presents results of radar cross section (RCS) calculations for several interesting targets using a method-of-moments...TERMS radar cross section, method of moments, finite element, modeling 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18... radar cross section (RCS) simulation that require an exact code for solution. In this report, we compare RCS calculations with two very different

  10. Accumulation of heavy metals and trace elements in fluvial sediments received effluents from traditional and semiconductor industries

    NASA Astrophysics Data System (ADS)

    Hsu, Liang-Ching; Huang, Ching-Yi; Chuang, Yen-Hsun; Chen, Ho-Wen; Chan, Ya-Ting; Teah, Heng Yi; Chen, Tsan-Yao; Chang, Chiung-Fen; Liu, Yu-Ting; Tzou, Yu-Min

    2016-09-01

    Metal accumulation in sediments threatens adjacent ecosystems due to the potential of metal mobilization and the subsequent uptake into food webs. Here, contents of heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) and trace elements (Ga, In, Mo, and Se) were determined for river waters and bed sediments that received sewage discharged from traditional and semiconductor industries. We used principal component analysis (PCA) to determine the metal distribution in relation to environmental factors such as pH, EC, and organic matter (OM) contents in the river basin. While water PCA categorized discharged metals into three groups that implied potential origins of contamination, sediment PCA only indicated a correlation between metal accumulation and OM contents. Such discrepancy in metal distribution between river water and bed sediment highlighted the significance of physical-chemical properties of sediment, especially OM, in metal retention. Moreover, we used Se XANES as an example to test the species transformation during metal transportation from effluent outlets to bed sediments and found a portion of Se inventory shifted from less soluble elemental Se to the high soluble and toxic selenite and selenate. The consideration of environmental factors is required to develop pollution managements and assess environmental risks for bed sediments.

  11. Determination of radioactive elements and heavy metals in sediments and soil from domestic water sources in northern peninsular Malaysia.

    PubMed

    Muhammad, Bashir G; Jaafar, Mohammad Suhaimi; Abdul Rahman, Azhar; Ingawa, Farouk Abdulrasheed

    2012-08-01

    Soil serves as a major reservoir for contaminants as it posseses an ability to bind various chemicals together. To safeguard the members of the public from an unwanted exposure, studies were conducted on the sediments and soil from water bodies that form the major sources of domestic water supply in northern peninsular Malaysia for their trace element concentration levels. Neutron Activation Analysis, using Nigeria Research Reactor-1 (NIRR-1) located at the Centre for Energy Research and Training, Zaria, Nigeria was employed as the analytical tool. The elements identified in major quantities include Na, K, and Fe while As, Br, Cr, U, Th, Eu, Cs, Co, La, Sm, Yb, Sc, Zn, Rb, Ba, Lu, Hf, Ta, and Sb were also identified in trace quantities. Gamma spectroscopy was also employed to analyze some soil samples from the same area. The results indicated safe levels in terms of the radium equivalent activity, external hazard index as well as the mean external exposure dose rates from the soil. The overall screening of the domestic water sources with relatively high heavy metals concentration values in sediments and high activity concentration values in soil is strongly recommended as their accumulation overtime as a consequence of leaching into the water may be of health concern to the members of the public.

  12. Segregation of cardiac and skeletal muscle-specific regulatory elements of the beta-myosin heavy chain gene.

    PubMed Central

    Rindt, H; Knotts, S; Robbins, J

    1995-01-01

    The beta-myosin heavy chain (beta-MyHC) gene is expressed in cardiac and slow skeletal muscles. To examine the regulatory sequences that are required for the gene's expression in the two compartments in vivo, we analyzed the expression pattern of a transgene consisting of the beta-MyHC gene 5' upstream region linked to the chloramphenicol acetyltransferase reporter gene. By using 5600 bp of 5' upstream region, the transgene was expressed at high levels in the slow skeletal muscles. Decreased levels of thyroid hormone led to the up-regulation of the transgene in both cardiac and skeletal muscles, mimicking the behavior of the endogenous beta-MyHC gene. After deleting the distal 5000 bp, the level of reporter gene expression was strongly reduced. However, decreased levels of thyroid hormone led to an 80-fold skeletal muscle-specific increase in transgene expression, even upon the ablation of a conserved cis-regulatory element termed MCAT, which under normal (euthyroid) conditions abolishes muscle-specific expression. In contrast, cardiac-specific induction was not detected with the deletion construct. These observations indicate that the cardiac and skeletal muscle regulatory elements can be functionally segregated on the beta-MyHC gene promoter. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:7878016

  13. Segregation of cardiac and skeletal muscle-specific regulatory elements of the beta-myosin heavy chain gene.

    PubMed

    Rindt, H; Knotts, S; Robbins, J

    1995-02-28

    The beta-myosin heavy chain (beta-MyHC) gene is expressed in cardiac and slow skeletal muscles. To examine the regulatory sequences that are required for the gene's expression in the two compartments in vivo, we analyzed the expression pattern of a transgene consisting of the beta-MyHC gene 5' upstream region linked to the chloramphenicol acetyltransferase reporter gene. By using 5600 bp of 5' upstream region, the transgene was expressed at high levels in the slow skeletal muscles. Decreased levels of thyroid hormone led to the up-regulation of the transgene in both cardiac and skeletal muscles, mimicking the behavior of the endogenous beta-MyHC gene. After deleting the distal 5000 bp, the level of reporter gene expression was strongly reduced. However, decreased levels of thyroid hormone led to an 80-fold skeletal muscle-specific increase in transgene expression, even upon the ablation of a conserved cis-regulatory element termed MCAT, which under normal (euthyroid) conditions abolishes muscle-specific expression. In contrast, cardiac-specific induction was not detected with the deletion construct. These observations indicate that the cardiac and skeletal muscle regulatory elements can be functionally segregated on the beta-MyHC gene promoter.

  14. Observations of heavy-element recombination lines in the Rho Ophiuchi dark cloud at 13 centimeters wavelength

    NASA Technical Reports Server (NTRS)

    Knapp, G. R.; Kuiper, T. B. H.; Brown, R. L.

    1976-01-01

    High-sensitivity observations at the carbon 140-alpha and 141-alpha recombination-line frequencies in the direction of the Rho Oph dust cloud show the presence of recombination lines of carbon and sulfur, but not of other heavy elements. These results require that the elements Si, Fe, and Mg are depleted by factors greater than 15, 10, and 2, respectively, most likely into interstellar grains, whereas sulfur is undepleted. They also require that only approximately one-sixth of the carbon is present in the gas phase in the cloud. From the observed size of the C II region together with the observed carbon depletion, it is inferred that the density in the carbon-line-emitting region is 25,000 per cu cm and that the size of the S II region is significantly larger than that of the C II region. The agreement between the widths of the recombination lines (which arise in a small region of the cloud) and those of the more widely distributed molecular species suggests that the lines in this cloud are broadened by microturbulence on a scale of much less than 0.1 pc.

  15. Accumulation of heavy metals and trace elements in fluvial sediments received effluents from traditional and semiconductor industries

    PubMed Central

    Hsu, Liang-Ching; Huang, Ching-Yi; Chuang, Yen-Hsun; Chen, Ho-Wen; Chan, Ya-Ting; Teah, Heng Yi; Chen, Tsan-Yao; Chang, Chiung-Fen; Liu, Yu-Ting; Tzou, Yu-Min

    2016-01-01

    Metal accumulation in sediments threatens adjacent ecosystems due to the potential of metal mobilization and the subsequent uptake into food webs. Here, contents of heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) and trace elements (Ga, In, Mo, and Se) were determined for river waters and bed sediments that received sewage discharged from traditional and semiconductor industries. We used principal component analysis (PCA) to determine the metal distribution in relation to environmental factors such as pH, EC, and organic matter (OM) contents in the river basin. While water PCA categorized discharged metals into three groups that implied potential origins of contamination, sediment PCA only indicated a correlation between metal accumulation and OM contents. Such discrepancy in metal distribution between river water and bed sediment highlighted the significance of physical-chemical properties of sediment, especially OM, in metal retention. Moreover, we used Se XANES as an example to test the species transformation during metal transportation from effluent outlets to bed sediments and found a portion of Se inventory shifted from less soluble elemental Se to the high soluble and toxic selenite and selenate. The consideration of environmental factors is required to develop pollution managements and assess environmental risks for bed sediments. PMID:27681994

  16. Viral expression cassette elements to enhance transgene target specificity and expression in gene therapy.

    PubMed

    Powell, Sara Kathleen; Rivera-Soto, Ricardo; Gray, Steven James

    2015-01-01

    Over the last five years, the number of clinical trials involving AAV (adeno-associated virus) and lentiviral vectors continue to increase by about 150 trials each year. For continued success, AAV and lentiviral expression cassettes need to be designed to meet each disease's specific needs. This review discusses how viral vector expression cassettes can be engineered with elements to enhance target specificity and increase transgene expression. The key differences relating to target specificity between ubiquitous and tissue-specific promoters are discussed, as well as how endogenous miRNAs and their target sequences have been used to restrict transgene expression. Specifically, relevant studies indicating how cis-acting elements such as introns, WPRE, polyadenylation signals, and the CMV enhancer are highlighted to show their utility for enhancing transgene expression in gene therapy applications. All discussion bears in mind that expression cassettes have space constraints. In conclusion, this review can serve as a menu of vector genome design elements and their cost in terms of space to thoughtfully engineer viral vectors for gene therapy.

  17. Determination of siderophile element characteristics throughout lunar history: Implications for the lunar magma ocean and late heavy bombardment

    NASA Astrophysics Data System (ADS)

    Sharp, Miriam Gregoria

    Examining the chemical behavior of highly siderophile elements (HSE) in impact events and during planetary differentiation can illuminate geologic processes that have affected the Moon. This dissertation addresses impactor compositions during the putative late heavy bombardment and the chemical composition of the evolving lunar magma ocean at both the times of core segregation and crust formation. Concentrations of the HSE Re, Os, Ir, Ru, Pt, and Pd and 187Os/188Os isotopic compositions are reported for seven Apollo 17 and four Apollo 16 impact melt rocks. Most Apollo 17 samples examined here as in prior studies are characterized by very similar HSE signatures, consistent with a common impactor that had suprachondritic Ru/Ir, Pd/Ir, and Re/Os. In contrast to the Apollo 17 signature, the Apollo 16 impact melts have a wider range of Ru/Ir, Pd/Ir, and Re/Os. This compositional range might be the result of sampling at least three impactor signatures at this site. Experimentally determined plagioclase-melt partition coefficients are also presented. These partition coefficients are used to estimate the concentrations of Sr, Hf, Ga, W, Mo, Ru, Pd, Au, Ni, and Co in a crystallizing lunar magma ocean at the point of plagioclase flotation. Plagioclase-melt derived concentrations for Sr, Ga, Ru, Pd, Au, Ni, and Co are also consistent with prior estimates. Estimates for Hf, W, and Mo, however, are higher. These elements may have concentrated in the residual liquid during fractional crystallization, due to their incompatibility. Experimentally determined metal-silicate partition coefficients are used to constrain the concentrations of W, Mo, Ru, Pd, Au, Ni, and Co in the lunar magma ocean at the time of core formation. The resulting lunar mantle estimates are generally consistent with previous estimates for the concentration of these elements in the lunar mantle. Together, these new results are used to present a compositional timeline for the Moon between the crystallization of

  18. Distinctive features of sputtering of Fe-Cr-Ni alloys containing heavy-element alloying constituent

    SciTech Connect

    Buchin, V.V.; Guseva, M.I.; Ivanov, S.M.; Nikol'skii, Y.V.; Stepanchikov, V.A.; Varga, L.

    1986-09-01

    Results are presented of a study of how radiation-induced segregation of admixtures in Fe-Cr-Ni alloys affects the composition and concentration of atoms sputtered by hydrogen ions. Targets of two Fe-Cr-Ni alloys, one of which contains 4% Mo and the other containing 5-7% Mo and 2-3% W, were bombarded with 10-keV hydrogen ions at 400 C in the ILU ion accelerator. A graph shows the distribution, found by means of Auger spectroscopy, of the components in a target of ChS-42P alloy after bombardment with hydrogen ions. The concentration of Fe, Ni, and Mo atoms decreased sharply and the concentration of Cr atoms increased. The coefficients for sputtering of Ni, Fe, and Cr by H/sup +/ ions differ only slightly, decreasing in the sequence Ni, Cr, Fe. The mass number of molybdenum is much greater than that of the main constituents of the alloy and the sputtering coefficient is minimal.

  19. A multi-element ICP-MS survey method as an alternative to the heavy metals limit test for pharmaceutical materials.

    PubMed

    Wang, T; Wu, J; Hartman, R; Jia, X; Egan, R S

    2000-10-01

    A multi-element inductively coupled plasma-mass spectrometry (ICP-MS) survey method has been demonstrated as an alternative to the antiquated 'heavy metals limit test' prescribed by United States Pharmacopoeia (USP), European Pharmacopoeia (EP), and British Pharmacopoeia (BP), for drug substances, intermediates, and raw materials. The survey method is simple, fast, sensitive, semi-quantitative to quantitative, and includes all the elements which can be analyzed by atomic spectroscopy.

  20. Antisense oligonucleotides targeting translation inhibitory elements in 5' UTRs can selectively increase protein levels.

    PubMed

    Liang, Xue-Hai; Sun, Hong; Shen, Wen; Wang, Shiyu; Yao, Joyee; Migawa, Michael T; Bui, Huynh-Hoa; Damle, Sagar S; Riney, Stan; Graham, Mark J; Crooke, Rosanne M; Crooke, Stanley T

    2017-09-19

    A variety of diseases are caused by deficiencies in amounts or activity of key proteins. An approach that increases the amount of a specific protein might be of therapeutic benefit. We reasoned that translation could be specifically enhanced using trans-acting agents that counter the function of negative regulatory elements present in the 5' UTRs of some mRNAs. We recently showed that translation can be enhanced by antisense oligonucleotides (ASOs) that target upstream open reading frames. Here we report the amount of a protein can also be selectively increased using ASOs designed to hybridize to other translation inhibitory elements in 5' UTRs. Levels of human RNASEH1, LDLR, and ACP1 and of mouse ACP1 and ARF1 were increased up to 2.7-fold in different cell types and species upon treatment with chemically modified ASOs targeting 5' UTR inhibitory regions in the mRNAs encoding these proteins. The activities of ASOs in enhancing translation were sequence and position dependent and required helicase activity. The ASOs appear to improve the recruitment of translation initiation factors to the target mRNA. Importantly, ASOs targeting ACP1 mRNA significantly increased the level of ACP1 protein in mice, suggesting that this approach has therapeutic and research potentials. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  1. Heavy metals and essential elements in Commerson's dolphins (Cephalorhynchus c. commersonii) from the southwestern South Atlantic Ocean.

    PubMed

    Cáceres-Saez, Iris; Ribeiro Guevara, Sergio; Dellabianca, Natalia A; Goodall, R Natalie P; Cappozzo, H Luis

    2013-07-01

    A survey of the elemental contents of K, Mg, Mn, Na, Cl, Br, Cs, Co, Rb, Fe, Zn, Al, Ti, V, As, Ag, Au and Cd in liver, kidney and muscle was performed in specimens of Commerson's dolphins (Cephalorhynchus c. commersonii) from subantarctic waters. The concentrations were determined by Instrumental Neutron Activation Analysis and the specimens derives from animals incidentally caught in artisanal fishing nets. Liver had the highest concentrations of Fe, 897(79) μg g(-1) DW (dry weight) (average; standard deviation in parenthesis), kidney had the highest Cd, 35 (24) μg g(-1) DW; Cl, 9,200 (1,700) μg g(-1) DW; Na, 6,800 (1,100) μg g(-1) DW and Br, 73(12) μg g(-1) DW; and muscle the highest Mg 954 (71) μg g(-1) DW. Potassium and Cs concentrations in muscle and kidney ranged in 12,510-13,020 and 0.230-0.252 μg g(-1) DW, respectively; Zn and Mn concentrations were similar in liver and kidney (117-122.1 and 3.66-16.5 μg g(-1) DW, respectively). Silver was high in liver 5.4(5.0) μg g(-1) DW and kidney 1.2(2.7) μg g(-1) DW. Gold, Rb, Co and As had no differences among tissues. Likewise, as in other odontocete species, the concentrations of essential elements showed little variation between the specimens analyzed, since they are regulated biochemically; however, heavy metals showed high variability. This study constitutes the first large description of the elemental composition in Commerson's dolphins from subantarctic waters of the South Atlantic Ocean.

  2. Heavy metals and trace elements in hair and urine of a sample of arab children with autistic spectrum disorder.

    PubMed

    Blaurock-Busch, Eleonor; Amin, Omnia R; Rabah, Thanaa

    2011-10-01

    General information: Autism is a severe developmental disorder which involves social withdrawal, communication deficits, and stereotypic/repetitive behavior. The pathophysiological etiologies which precipitate autism symptoms remain elusive and controversial in many cases, but both genetic and environmental factors (and their interactions) have been implicated. While autism is considered multicausal, environmental factors have received significant attention. International discussion has ocused on neurotoxins such as mercury and lead, suggesting that these and other toxic metals contribute to the development of the disorder. An epidemiological study released in 2006 (Palmer et al.) linking Toxic Release Inventory (TRI) data on mercury to special education data in Texas reported a 61% increase in autism prevalence rates (or 17% adjusted) per 1000 pounds of mercury released into the environment (1). We attempted to further evaluate whether exposure to variable environmental contributes to the genesis of autistic spectrum disorder, and thus is a factor increasing the risk for developing autism symptoms in utero or in early childhood. The purpose of this study is to examine possible environmental risk factors and sources of exposure to mercury and other heavy metals in children with autism spectrum disorder versus controls. Through laboratory diagnostics we are able to distinguish between present and past exposure (i.e. hair analysis measurements reflect past exposure), urinary excretion levels of unprovoked urine represent immediate exposure. By assessing a spectrum of trace elements and heavy metals in hair and urine of both autistic and control groups, we focused on the participants≈ past and present exposure. The participants were 25 Autistic Spectrum Disorder (ASD) children (22 boys and 3 girls) between the age of 3 and 9 years. They were either diagnosed previously by other psychiatrist, psychologist, and developmental pediatrician or suspected by their parents

  3. Reaction dynamics induced by the radioactive ion beam 7Be on medium-mass and heavy targets

    NASA Astrophysics Data System (ADS)

    Mazzocco, M.; Boiano, A.; Boiano, C.; La Commara, M.; Manea, C.; Parascandolo, C.; Pierroutsakou, D.; Stefanini, C.; Strano, E.; Torresi, D.; Acosta, L.; Di Meo, P.; Fernandez-Garcia, J. P.; Glodariu, T.; Grebosz, J.; Guglielmetti, A.; Keeley, N.; Lay, J. A.; Marquinez-Duran, G.; Martel, I.; Mazzocchi, C.; Molini, P.; Nicoletto, M.; Pakou, A.; Parkar, V. V.; Rusek, K.; Sánchez-Benítez, A. M.; Sandoli, M.; Sava, T.; Sgouros, O.; Signorini, C.; Silvestri, R.; Soramel, F.; Soukeras, V.; Stiliaris, E.; Stroe, L.; Toniolo, N.; Zerva, K.

    2015-10-01

    We studied the reaction dynamics induced at Coulomb barrier energies by the weakly-bound Radioactive Ion Beam 7Be (Sα = 1.586 MeV) on medium-mass (58Ni) and heavy (208Pb) targets. The experiments were performed at INFN-LNL (Italy), where a 2-3×105 pps 7Be secondary beam was produced with the RIB in-flight facility EXOTIC. Charged reaction products were detected by means of high-granularity silicon detectors in rather wide angular ranges. The contribution presents an up-to-date status of the data analysis and theoretical interpretation for both systems.

  4. Photon plus heavy-quark production in high-energy collisions within the target rest frame formalism

    SciTech Connect

    Betemps, M. A.; Machado, M. V. T.

    2010-11-01

    We apply the target rest frame formalism to photon+heavy quark production cross section in hadronic collisions at high energies. We investigate the dependence of the production cross section on the photon and quark rapidities and transverse momenta. It is shown that the photon transverse momentum spectrum is a sensitive probe of color dipole scattering amplitude. The theoretical results are compared to Tevatron measurements of the differential {gamma}+c+X and {gamma}+b+X production cross sections at {radical}(s)=1.96 TeV. An analysis for proton-proton and proton-lead collisions at the LHC regime is also performed.

  5. Electronic Structure Calculations for Heavy Elements: Radon (Z=86) and Francium (Z=87)

    NASA Astrophysics Data System (ADS)

    Koufos, Alexander; Papaconstantopoulos, Dimitrios

    2010-03-01

    Electronic structure calculations allow scientists to predict the properties of solids without the use of physical material. Although the ability to manipulate matter has improved dramatically within the past couple decades, some matter is still hard to study. Modern computers not only let us study this matter, but allow us to do it more quickly and just as accurately. The electronic structure of two rare and mostly unstudied elements, Radon (Z=86) and Francium (Z=87), has been calculated. The augmented plane wave (APW) method with local density approximation (LDA) functional as well as the linearized augmented plane wave (LAPW) method with both LDA and generalized gradient approximation (GGA) functionals were used to perform the calculations. Francium total energy calculations gave the fcc structure slightly below the bcc structure with a minimal energy difference of δE=0.33mRy. The difference found is consistent with other alkali metal total energy calculations which do not verify the bcc structure to be the ground state. Radon was predicted to be an insulator with a gap of 0.931 Ry similar to the other noble gases.

  6. Atomic structure of the super-heavy element No I (Z=102)

    NASA Astrophysics Data System (ADS)

    Liu, Yong; Hutton, Roger; Zou, Yaming

    2007-12-01

    The multiconfiguration Dirac-Fock (MCDF) method was used to calculate the excitation energies of the levels of P3 and P1 in the lowest excited configurations for the two homolog elements of No I and Yb I. Also the transition probability of the 7s7pP11→7s2S10 transition and the ground-state ionization energy of No I were calculated. The results for Yb I agree very well with the available experiments, with deviations of below 0.6% for the triplets and below 4% for the singlet. The result for the No I excitation energies clears the situation of conflicting results between Borschevsky , 30056cm-1 (3.726 eV) [Phys. Rev. A 75, 042514 (2007)], and Fritzsche, 3.36 eV [Eur. Phys. J. D 33, 15 (2005)] for the 7s7pP11 level, which is planned to be measured in the near future with a newly developed experimental technique by Backe [Eur. Phys. J. D 45, 99 (2007)]. The ionization energy result obtained in this work, 53701cm-1 , is in excellent agreement with the scaled result of 53600(600)cm-1 .

  7. Atomic structure of the super-heavy element No I (Z=102)

    SciTech Connect

    Liu, Yong; Hutton, Roger; Zou Yaming

    2007-12-15

    The multiconfiguration Dirac-Fock (MCDF) method was used to calculate the excitation energies of the levels of {sup 3}P and {sup 1}P in the lowest excited configurations for the two homolog elements of No I and Yb I. Also the transition probability of the 7s7p {sup 1}P{sub 1}{yields}7s{sup 2} {sup 1}S{sub 0} transition and the ground-state ionization energy of No I were calculated. The results for Yb I agree very well with the available experiments, with deviations of below 0.6% for the triplets and below 4% for the singlet. The result for the No I excitation energies clears the situation of conflicting results between Borschevsky et al., 30 056 cm{sup -1} (3.726 eV) [Phys. Rev. A 75, 042514 (2007)], and Fritzsche, 3.36 eV [Eur. Phys. J. D 33, 15 (2005)] for the 7s7p {sup 1}P{sub 1} level, which is planned to be measured in the near future with a newly developed experimental technique by Backe et al. [Eur. Phys. J. D 45, 99 (2007)]. The ionization energy result obtained in this work, 53 701 cm{sup -1}, is in excellent agreement with the scaled result of 53 600(600) cm{sup -1}.

  8. Elemental Abundances of Ultra-Heavy Nuclei Measured by SuperTIGER: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Murphy, R. P.; Binns, W. R.; Bose, R. G.; Dowkontt, P. F.; Israel, M. H.; Rauch, B. F.; Ward, J. E.; Brandt, T. J.; de Nolfo, G. A.; Hams, T.; Link, J. T.; Mitchell, J. W.; Sakai, K.; Sasaki, M.; Labrador, A. W.; Mewaldt, R. A.; Stone, E. C.; Waddington, C. J.; Wiedenbeck, M. E.

    2014-03-01

    The SuperTIGER (Trans-Iron Galactic Element Recorder) experiment was launched on a long-duration balloon flight from Williams Field, Antarctica, on December 8, 2012 and flew for a total of 55 days at a mean atmospheric depth of 4.4 g/cm2. The instrument is designed to measure the abundances of galactic cosmic rays in the charge (Z) range from 10 <= Z <= 40 with high statistical precision and excellent charge resolution, with exploratory measurements into the 40 < Z <= 60 range. The instrument, the methods of charge identification that are employed, and the SuperTIGER balloon flight will be described. The data that will be presented contain more than 600 events with charge 30 < Z <= 40, ~ 4.5x that collected by the two TIGER flights combined. The charge resolution obtained for iron is <0.18 cu. We will discuss the OB association model for the origin of galactic cosmic rays and show how SuperTIGER measurements will be used as a stringent test of this model. This research was supported by NASA under grants NNX09AC17G and NNX14AB25G and by the McDonnell Center for the Space Sciences at Washington University.

  9. Hubble Space Telescope observations of cool white dwarf stars: Detection of new species of heavy elements

    NASA Technical Reports Server (NTRS)

    Shipman, Harry; Barnhill, Maurice; Provencal, Judi; Roby, Scott; Bues, Irmela; Cordova, France; Hammond, Gordon; Hintzen, Paul; Koester, Detlev; Liebert, James

    1995-01-01

    Observations of cool white dwarf stars with the Hubble Space Telescope (HST) has uncovered a number of spectral features from previouslly unobserved species. In this paper we present the data on four cool white dwarfs. We present identifications, equivalent width measurements, and brief summaries of the significance of our findings. The four stars observed are GD 40 (DBZ3, G 74-7 (DAZ), L 745-46A (DZ), and LDS 749B (DBA). Many additional species of heavey elements were detected in GD 40 and G 74-7. In L 745-46A, while the detections are limited to Fe 1, Fe II, and Mg II, the quality of the Mg II h and K line profiles should permit a test of the line broadening theories, which are so crucial to abundance determinations. The clear detection of Mg II h and k in LDS 749 B should, once an abundance determination is made, provide a clear test of the hypothesis that the DBA stars are the result of accretion from the interstellar medium. This star contains no other clear features other than a tantalizing hint of C II 1335 with a P Cygni profile, and some expected He 1 lines.

  10. Hubble Space Telescope observations of cool white dwarf stars: Detection of new species of heavy elements

    NASA Technical Reports Server (NTRS)

    Shipman, Harry; Barnhill, Maurice; Provencal, Judi; Roby, Scott; Bues, Irmela; Cordova, France; Hammond, Gordon; Hintzen, Paul; Koester, Detlev; Liebert, James

    1995-01-01

    Observations of cool white dwarf stars with the Hubble Space Telescope (HST) has uncovered a number of spectral features from previouslly unobserved species. In this paper we present the data on four cool white dwarfs. We present identifications, equivalent width measurements, and brief summaries of the significance of our findings. The four stars observed are GD 40 (DBZ3, G 74-7 (DAZ), L 745-46A (DZ), and LDS 749B (DBA). Many additional species of heavey elements were detected in GD 40 and G 74-7. In L 745-46A, while the detections are limited to Fe 1, Fe II, and Mg II, the quality of the Mg II h and K line profiles should permit a test of the line broadening theories, which are so crucial to abundance determinations. The clear detection of Mg II h and k in LDS 749 B should, once an abundance determination is made, provide a clear test of the hypothesis that the DBA stars are the result of accretion from the interstellar medium. This star contains no other clear features other than a tantalizing hint of C II 1335 with a P Cygni profile, and some expected He 1 lines.

  11. The LLNL Heavy Element Facility -- Facility Management, Authorization Basis, and Readiness Assessment Lessons Learned in the Heavy Element Facility (B251) Transition from Category II Nuclear Facility to Radiological Facility

    SciTech Connect

    Mitchell, M; Anderson, B; Brown, E; Gray, L

    2006-04-10

    This paper presents Facility Management, Readiness Assessment, and Authorization Basis experience gained and lessons learned during the Heavy Element Facility Risk Reduction Program (RRP). The RRP was tasked with removing contaminated glove boxes, radioactive inventory, and contaminated ventilation systems from the Heavy Element Facility (B251) at Lawrence Livermore National Laboratory (LLNL). The RRP was successful in its goal in April 2005 with the successful downgrade of B251 from a Category II Nuclear Facility to a Radiological Facility. The expertise gained and the lessons learned during the planning and conduct of the RRP included development of unique approaches in work planning/work control (''Expect the unexpected and confirm the expected'') and facility management. These approaches minimized worker dose and resulted in significant safety improvements and operational efficiencies. These lessons learned can help similar operational and management activities at other sites, including facilities restarting operations or new facility startup. B251 was constructed at LLNL to provide research areas for conducting experiments in radiochemistry using transuranic elements. Activities at B251 once included the preparation of tracer sets associated with the underground testing of nuclear devices and basic research devoted to a better understanding of the chemical and nuclear behavior of the transuranic elements. Due to the age of the facility, even with preventative maintenance, facility safety and experimental systems were deteriorating. A variety of seismic standards were used in the facility design and construction, which encompassed eight building increments constructed over a period of 26 years. The cost to bring the facility into compliance with the current seismic and other requirements was prohibitive, and simply maintaining B251 as a Category II nuclear facility posed serious cost considerations under a changing regulatory environment. Considering the high

  12. Light and Heavy Element Abundance Variations in the Outer Halo Globular Cluster NGC 6229

    NASA Astrophysics Data System (ADS)

    Johnson, Christian I.; Caldwell, Nelson; Rich, R. Michael; Walker, Matthew G.

    2017-10-01

    NGC 6229 is a relatively massive outer halo globular cluster that is primarily known for exhibiting a peculiar bimodal horizontal branch morphology. Given the paucity of spectroscopic data on this cluster, we present a detailed chemical composition analysis of 11 red giant branch members based on high resolution (R ≈ 38,000), high S/N (>100) spectra obtained with the MMT-Hectochelle instrument. We find the cluster to have a mean heliocentric radial velocity of -{138.1}-1.0+1.0 {km} {{{s}}}-1, a small dispersion of {3.8}-0.7+1.0 {km} {{{s}}}-1, and a relatively low {(M/{L}{{V}})}ȯ ={0.82}-0.28+0.49. The cluster is moderately metal-poor with < [{Fe}/{{H}}]> =-1.13 dex and a modest dispersion of 0.06 dex. However, 18% (2/11) of the stars in our sample have strongly enhanced [La, Nd/Fe] ratios that are correlated with a small (∼0.05 dex) increase in [Fe/H]. NGC 6229 shares several chemical signatures with M75, NGC 1851, and the intermediate metallicity populations of ω Cen, which lead us to conclude that NGC 6229 is a lower mass iron-complex cluster. The light elements exhibit the classical (anti-)correlations that extend up to Si, but the cluster possesses a large gap in the O–Na plane that separates first and second generation stars. NGC 6229 also has unusually low [Na, Al/Fe] abundances that are consistent with an accretion origin. A comparison with M54 and other Sagittarius clusters suggests that NGC 6229 could also be the remnant core of a former dwarf spheroidal galaxy.

  13. Regulatory elements necessary for termination of transcription within the immunoglobulin heavy chain gene locus

    SciTech Connect

    Moore, B.B.

    1992-01-01

    Previous experimentation demonstrated that regulation of the IgM only phenotype in both pre-B and immature B cells was primarily at the transcriptional level. Expression of IgD mRNA involves transcription of the entire 29 kilobase rearranged [mu]-[delta] locus. Mature B cells transcribe the [beta] exons at approximately half the level that they transcribe the [delta] gene. Early B cells however, transcribe the [mu] gene with approximately 90% more efficiency than they do the [delta] gene. Specifically, early B cells show a transcription termination event occurring within a 1 kilobase region of the [mu]-[delta] intron. This dissertation analyzes the sequence elements necessary to encode the transcription termination event within the [mu]-[delta] intron. This work shows that the termination motif consists of specific sequences within the [mu]m poly(A) site as well as a region of the [mu]-[delta] intron contained within a 1200 base pair fragment. The 1200 base pair fragment extends from the Pst I site within the intron and ends just prior to the C[delta]1 exon. This fragment contains a 162 base pair unique sequence inverted repeat (USIR). Furthermore, the [mu]m site is specifically required because the [mu]s site was unable to substitute, despite extensive usage. In addition, the USIR-containing intron functions in an orientation-dependent manner. Analysis of this termination motif in a variety of lymphoid and non-lymphoid cells suggests that this motif is an intrinsic polymerase II termination motif. This implies that transcription termination in early B cells is by a default model and that active regulation of this motif involves an anti-termination event in mature B cells.

  14. Development of a high intensity 48Ca ion beam for the heavy element program

    SciTech Connect

    Wutte, Daniela; Leitner, Mattheus; Lyneis, Claude

    2002-02-02

    A high intensity {sup 48}Ca ion beam has been developed at the 88 Inch Cyclotron for the synthesis of {sup 283}112 using the reaction {sup 238}U({sup 48}Ca, 3n). An ion beam intensity of {approx} 700 pnA was delivered on target, resulting in a total dose of 2 x 10{sup 18} ions over a six day period. Since {sup 48}Ca is a very expensive and rare isotope minimal consumption is essential. Therefore a new oven [1] and special tantalum liner [2] have been developed for the AECR-U ion source during the last year to improve the metal ion beam efficiency. Both the LBL ECR and the AECR-U ion sources are built with radial access. Six radial slots between the sextupole magnet bars provide additional pumping and easy access to the plasma chamber for ovens and feedthroughs. Two types of radial ovens have been used at LBNL in the past, operating at temperatures up to 2100 C.

  15. Bioavailability of heavy metals, germanium and rare earth elements at Davidschacht dump-field in mine affected area of Freiberg (Saxony)

    NASA Astrophysics Data System (ADS)

    Midula, Pavol; Wiche, Oliver

    2016-04-01

    Bioavailability research presents an essential tool, in modern phytoremediation and phytomining technologies, allowing the estimation of plant available fractions of elements in soils. However, up to date, sufficient interdisciplinary knowledge on the biogeochemically impacted behavior of specific target elements, in particular Ge and REEs in mining affected soils and their uptake into strategically used plants is lacking. This presented work is focused on a correlation study between the concentrations of selected heavy metals, Ge and REEs in soils formed on the top of the dump-field of Davidschacht and the corresponding their concentrations in 12 vascular plant species. The mine-dump of Davidschacht, situated in the Freiberg (Saxony, Germany) municipality area was chosen as the study area, which has been considered to be a high contaminated enclave, due to the mining history of the region. In total 12 sampling sites with differing composition of plant species were selected. At each sampling site soil samples from a soil depth of 0 - 10 cm and samples of plant material (shoots) were taken. The soil samples were analysed for total concentration of elements, pH (H2O) and consequently analysed by 4-step sequential extraction (SE) to determine fractions of elements that are mobile (fraction 1), acid soluble (pH 5) (fraction 2), bound to organic and oxidizable matter (fraction 3) and bound to amorphic oxides (fraction 4). The plant material was decomposed by hydrofluoric acid in order to extract the elements. Concentrations of elements in soil extracts and digestion solutions were analysed by ICP-MS. For all species bioconcentration factor (BCF) was calculated of the total concentration of elements in order to investigate the bioaccumulation potential. Arsenic (As), cadmium (Cd) and lead (Pb) were chosen as the representative heavy metals. Within the REEs neodymium (Nd) and cerium (Ce) were selected as representatives for all REEs, since Nd and Ce correlated significant

  16. Identification of a 94-bp GC-rich element in the smooth muscle myosin heavy-chain promoter controlling vascular smooth muscle cell-specific gene expression.

    PubMed

    Deindl, Elisabeth; Middeler, Guido; Müller, Oliver J; Selbert, Stefan; Schlenke, Peter; Marienfeld, Uta; Thirion, Christian; Katus, Hugo A; Franz, Wolfgang M

    2006-01-01

    The previously described rabbit 2.3-kilobase smooth muscle myosin heavy-chain (SMHCwt) promoter targets gene expression in transgenic animals to vascular smooth muscle cells (SMCs), including coronary arteries. Therefore, SMHCwt is thought to provide a promising tool for human gene therapy. In the present study, we examined tissue specificity and expression levels of wild-type and mutated SMHC promoters within the system of high-capacity adenoviral (hcAd) vectors. SMHCwt and a series of SMHC promoter deletion mutants, a triple promoter as well as a cytomegalovirus-SMHC hybrid promoter driving the enhanced green fluorescence protein (EGFP) reporter gene were transiently transfected into aortic SMCs. Fluorescence intensity was measured by flow cytometric analysis. Consecutively, hcAd vectors were constructed with the SMHCwt and the mutant promoter with the highest fluorescence activity. Levels of EGFP expression were determined after transduction of SMCs derived from human coronary arteries. For analysis of tissue specificity, embryonic stem (ES) cell-derived SMCs (ESdSMHCs) and cardiomyocytes (ESdCMs) were used. In comparison with SMHCwt, only the SMHCdel94 mutant lacking a 94-bp GC-rich element revealed a 1.5-fold increased fluorescence activity. Transduction of primary SMCs of human coronary arteries with hcAd vectors confirmed an increased EGFP expression driven by the SMHCdel94 promoter. In ES-cell-derived embryoid bodies, SMHCwt was exclusively active in transduced ESdSMCs. In contrast, expression of SMHCdel94 was also found in ESdCMs and other nontarget cells of the embryoid body. The tissue-specific rabbit SMHCwt promoter seems to be suitable for adenoviral gene transfer in SMCs of human coronary arteries and deletion of a 94-bp negative cis-acting GC-rich element results in loss of specificity.

  17. Heavy element abundances in Ap stars from ultraviolet data. I - The bright reference stars Alpha Lyrae and Alpha Canis Majoris A

    NASA Technical Reports Server (NTRS)

    Boiarchuk, A. A.; Snow, T. P., Jr.

    1978-01-01

    Curve-of-growth analysis is used to derive chemical abundances in Alpha Lyr and Alpha CMa, based on ultraviolet spectra obtained with Copernicus. This analysis is part of a program to study the abundances of the heavy elements mercury and platinum and the short-lived element technetium in the atmospheres of Ap and Am stars. Ultraviolet Fe II lines are used to establish the curves of growth for Alpha Lyr and Alpha CMa A; abundances of a variety of elements, along with upper limits on Hg, Pt, and Tc, are derived. In cases where previous studies based on visual spectra have included elements in common with the present analysis, the agreement is good within the known uncertainties. One new element, cadmium, is observed for these two stars. The upper limits on Pt and Hg, as well as Tc, show that these elements are probably not enhanced in Alpha CMa A by more than about one order of magnitude.

  18. Heavy element abundances in Ap stars from ultraviolet data. I - The bright reference stars Alpha Lyrae and Alpha Canis Majoris A

    NASA Technical Reports Server (NTRS)

    Boiarchuk, A. A.; Snow, T. P., Jr.

    1978-01-01

    Curve-of-growth analysis is used to derive chemical abundances in Alpha Lyr and Alpha CMa, based on ultraviolet spectra obtained with Copernicus. This analysis is part of a program to study the abundances of the heavy elements mercury and platinum and the short-lived element technetium in the atmospheres of Ap and Am stars. Ultraviolet Fe II lines are used to establish the curves of growth for Alpha Lyr and Alpha CMa A; abundances of a variety of elements, along with upper limits on Hg, Pt, and Tc, are derived. In cases where previous studies based on visual spectra have included elements in common with the present analysis, the agreement is good within the known uncertainties. One new element, cadmium, is observed for these two stars. The upper limits on Pt and Hg, as well as Tc, show that these elements are probably not enhanced in Alpha CMa A by more than about one order of magnitude.

  19. Morpholino antisense oligonucleotides targeting intronic repressor Element1 improve phenotype in SMA mouse models.

    PubMed

    Osman, Erkan Y; Miller, Madeline R; Robbins, Kate L; Lombardi, Abby M; Atkinson, Arleigh K; Brehm, Amanda J; Lorson, Christian L

    2014-09-15

    Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by the loss of Survival Motor Neuron-1 (SMN1). In all SMA patients, a nearly identical copy gene called SMN2 is present, which produces low levels of functional protein owing to an alternative splicing event. To prevent exon-skipping, we have targeted an intronic repressor, Element1 (E1), located upstream of SMN2 exon 7 using Morpholino-based antisense oligonucleotides (E1(MO)-ASOs). A single intracerebroventricular injection in the relatively severe mouse model of SMA (SMNΔ7 mouse model) elicited a robust induction of SMN protein, and mean life span was extended from an average survival of 13 to 54 days following a single dose, consistent with large weight gains and a correction of the neuronal pathology. Additionally, E1(MO)-ASO treatment in an intermediate SMA mouse (SMN(RT) mouse model) significantly extended life span by ∼700% and weight gain was comparable with the unaffected animals. While a number of experimental therapeutics have targeted the ISS-N1 element of SMN2 pre-mRNA, the development of E1 ASOs provides a new molecular target for SMA therapeutics that dramatically extends survival in two important pre-clinical models of disease.

  20. Numerical study of heavy-ion stopping in foam targets with one-dimensional subcell-scale hydrodynamic motions

    NASA Astrophysics Data System (ADS)

    Oguri, Y.; Kondo, K.; Hasegawa, J.

    2014-01-01

    Heavy-ion stopping in foam targets with subcell-scale hydro motions was numerically investigated in relation to ion-driven warm dense matter experiments. To simulate porous foam targets, we employed a simple 1D periodic multilayer model consisting of thin solid slabs and gaps between them. The averaged pore diameter and cell-wall thickness of the foam were represented by the gap width between the slabs and the slab thickness, respectively. The density- and temperature-dependent projectile stopping cross-sections were evaluated using a binary encounter model taking into account the electronic state of target atoms during heating and expansion. We employed a combination of 11Na projectiles and subrange 13Al foam targets with ρ=0.05ρsolid. The hydrodynamic motion of the target was calculated with a 1D code. During homogenization, hot dense spots appeared at the original gap positions, owing to stagnation of the jets. As a result, even after the pores were filled with blow-off materials, the initial inhomogeneity was not completely smeared out, and the total energy loss was still not equal to that in the homogeneous equivalent, especially for large pore sizes.

  1. Evaluation of Segmented Amorphous-Contact Planar Germanium Detectors for Heavy-Element Research

    NASA Astrophysics Data System (ADS)

    Jackson, Emily G.

    The challenge of improving our understanding of the very heaviest nuclei is at the forefront of contemporary low-energy nuclear physics. In the last two decades, "in-beam" spectroscopy experiments have advanced from Z=98 to Z=104, Rutherfordium, allowing insights into the dynamics of the fission barrier, high-order deformations, and pairing correlations. However, new detector technologies are needed to advance to even heavier nuclei. This dissertation is aimed at evaluating one promising new technology; large segmented planar germanium wafers for this area of research. The current frontier in gamma-ray spectroscopy involves large-volume (>9 cm thick) coaxial detectors that are position sensitive and employ gamma-ray "tracking". In contrast, the detectors assessed in this dissertation are relatively thin (~1 cm) segmented planar wafers with amorphous-germanium strip contacts that can tolerate extremely high gamma-ray count rates, and can accommodate hostile neutron fluxes. They may be the only path to heavier "in-beam" spectroscopy with production rates below 1 nanobarn. The resiliency of these detectors against neutron-induced damage is examined. Two detectors were deliberately subjected to a non-uniform neutron fluence leading to considerable degradation of performance. The neutrons were produced using the 7Li(p, n)7Be reaction at the UMass Lowell Van-de-Graaff accelerator with a 3.7-MeV proton beam incident on a natural Li target. The energy of the neutrons emitted at zero degrees was 2.0 MeV, close to the mean energy of the fission neutron spectrum, and each detector was exposed to a fluence >3.6 x109 n/cm2. A 3-D software "trap-corrector" gain-matching algorithm considerably restored the overall performance. Other neutron damage mitigation tactics were explored including over biasing the detector and flooding the detector with a high gamma-ray count rate. Various annealing processes to remove neutron damage were investigated. An array of very large diameter

  2. Magnetocaloric effect in heavy rare-earth elements doped Fe-based bulk metallic glasses with tunable Curie temperature

    SciTech Connect

    Li, Jiawei; Huo, Juntao; Chang, Chuntao E-mail: dujun@nimte.ac.cn; Du, Juan E-mail: dujun@nimte.ac.cn; Man, Qikui; Wang, Xinmin; Li, Run-Wei; Law, Jiayan

    2014-08-14

    The effects of heavy rare earth (RE) additions on the Curie temperature (T{sub C}) and magnetocaloric effect of the Fe-RE-B-Nb (RE = Gd, Dy and Ho) bulk metallic glasses were studied. The type of dopping RE element and its concentration can easily tune T{sub C} in a large temperature range of 120 K without significantly decreasing the magnetic entropy change (ΔS{sub M}) and refrigerant capacity (RC) of the alloys. The observed values of ΔS{sub M} and RC of these alloys compare favorably with those of recently reported Fe-based metallic glasses with enhanced RC compared to Gd{sub 5}Ge{sub 1.9}Si{sub 2}Fe{sub 0.1}. The tunable T{sub C} and large glass-forming ability of these RE doped Fe-based bulk metallic glasses can be used in a wide temperature range with the final required shapes.

  3. Geochemistry of dissolved trace elements and heavy metals in the Dan River Drainage (China): distribution, sources, and water quality assessment.

    PubMed

    Meng, Qingpeng; Zhang, Jing; Zhang, Zhaoyu; Wu, Tairan

    2016-04-01

    Dissolved trace elements and heavy metals in the Dan River drainage basin, which is the drinking water source area of South-to-North Water Transfer Project (China), affect large numbers of people and should therefore be carefully monitored. To investigate the distribution, sources, and quality of river water, this study integrating catchment geology and multivariate statistical techniques was carried out in the Dan River drainage from 99 river water samples collected in 2013. The distribution of trace metal concentrations in the Dan River drainage was similar to that in the Danjiangkou Reservoir, indicating that the reservoir was significantly affected by the Dan River drainage. Moreover, our results suggested that As, Sb, Cd, Mn, and Ni were the major pollutants. We revealed extremely high concentrations of As and Sb in the Laoguan River, Cd in the Qingyou River, Mn, Ni, and Cd in the Yinhua River, As and Sb in the Laojun River, and Sb in the Dan River. According to the water quality index, water in the Dan River drainage was suitable for drinking; however, an exposure risk assessment model suggests that As and Sb in the Laojun and Laoguan rivers could pose a high risk to humans in terms of adverse health and potential non-carcinogenic effects.

  4. Design and discovery of a novel half-Heusler transparent hole conductor made of all-metallic heavy elements.

    PubMed

    Yan, Feng; Zhang, Xiuwen; Yu, Yonggang G; Yu, Liping; Nagaraja, Arpun; Mason, Thomas O; Zunger, Alex

    2015-06-24

    Transparent conductors combine two generally contradictory physical properties, but there are numerous applications where both functionalities are crucial. Previous searches focused on doping wide-gap metal oxides. Focusing instead on the family of 18 valence electron ternary ABX compounds that consist of elements A, B and X in 1:1:1 stoichiometry, we search theoretically for electronic structures that simultaneously lead to optical transparency while accommodating intrinsic defect structures that produce uncompensated free holes. This leads to the prediction of a stable, never before synthesized TaIrGe compound made of all-metal heavy atom compound. Laboratory synthesis then found it to be stable in the predicted crystal structure and p-type transparent conductor with a strong optical absorption peak at 3.36 eV and remarkably high hole mobility of 2,730 cm(2) V(-1) s(-1) at room temperature. This methodology opens the way to future searches of transparent conductors in unexpected chemical groups.

  5. Simultaneous atomic-resolution electron ptychography and Z-contrast imaging of light and heavy elements in complex nanostructures

    PubMed Central

    Yang, H.; Rutte, R. N.; Jones, L.; Simson, M.; Sagawa, R.; Ryll, H.; Huth, M.; Pennycook, T. J.; Green, M.L.H.; Soltau, H.; Kondo, Y.; Davis, B. G.; Nellist, P. D.

    2016-01-01

    The aberration-corrected scanning transmission electron microscope (STEM) has emerged as a key tool for atomic resolution characterization of materials, allowing the use of imaging modes such as Z-contrast and spectroscopic mapping. The STEM has not been regarded as optimal for the phase-contrast imaging necessary for efficient imaging of light materials. Here, recent developments in fast electron detectors and data processing capability is shown to enable electron ptychography, to extend the capability of the STEM by allowing quantitative phase images to be formed simultaneously with incoherent signals. We demonstrate this capability as a practical tool for imaging complex structures containing light and heavy elements, and use it to solve the structure of a beam-sensitive carbon nanostructure. The contrast of the phase image contrast is maximized through the post-acquisition correction of lens aberrations. The compensation of defocus aberrations is also used for the measurement of three-dimensional sample information through post-acquisition optical sectioning. PMID:27561914

  6. Korteweg-de Vries-Burgers equation in a multi-component magnetized plasma with nuclei of heavy elements

    NASA Astrophysics Data System (ADS)

    Hosen, B.; Amina, M.; Mamun, A. A.; Hossen, M. R.

    2016-12-01

    The nonlinear properties of ion-acoustic (IA) waves are investigated in a relativistically degenerate magnetized quantum plasma, whose constituents are non-degenerate inertial ions, degenerate electrons and immobile positively-charged heavy elements. For nonlinear studies, the well-known reductive perturbation technique is employed to derive the Korteweg-de Vries-Burger equation in the presence of relativistically degenerate electrons. Numerically, the amplitude, width, and phase speed are shown to be associated with the localized IA solitons, and shocks are shown to be significantly influenced by the various intrinsic parameters relevant to our model. The solitary and the shock wave properties have been to be influenced in the non-relativistic, as well as the ultrarelativistic, limits. The effects of the external magnetic field and the obliqueness are found to change the basic properties of IA waves significantly. The present analysis can be useful in understanding the collective process in dense astrophysical environments, like there of non-rotating white dwarfs, neutron stars, etc.

  7. Simultaneous atomic-resolution electron ptychography and Z-contrast imaging of light and heavy elements in complex nanostructures

    NASA Astrophysics Data System (ADS)

    Yang, H.; Rutte, R. N.; Jones, L.; Simson, M.; Sagawa, R.; Ryll, H.; Huth, M.; Pennycook, T. J.; Green, M. L. H.; Soltau, H.; Kondo, Y.; Davis, B. G.; Nellist, P. D.

    2016-08-01

    The aberration-corrected scanning transmission electron microscope (STEM) has emerged as a key tool for atomic resolution characterization of materials, allowing the use of imaging modes such as Z-contrast and spectroscopic mapping. The STEM has not been regarded as optimal for the phase-contrast imaging necessary for efficient imaging of light materials. Here, recent developments in fast electron detectors and data processing capability is shown to enable electron ptychography, to extend the capability of the STEM by allowing quantitative phase images to be formed simultaneously with incoherent signals. We demonstrate this capability as a practical tool for imaging complex structures containing light and heavy elements, and use it to solve the structure of a beam-sensitive carbon nanostructure. The contrast of the phase image contrast is maximized through the post-acquisition correction of lens aberrations. The compensation of defocus aberrations is also used for the measurement of three-dimensional sample information through post-acquisition optical sectioning.

  8. Investigation of heavy-ion fusion with deformed surface diffuseness: Actinide and lanthanide targets

    NASA Astrophysics Data System (ADS)

    Alavi, S. A.; Dehghani, V.

    2017-05-01

    By using a deformed Broglia-Winther nuclear interaction potential in the framework of the WKB method, the near- and above-barrier heavy-ion-fusion cross sections of 16O with some lanthanides and actinides have been calculated. The effect of deformed surface diffuseness on the nuclear interaction potential, the effective interaction potential at distinct angle, barrier position, barrier height, cross section at each angles, and fusion cross sections of 16O+147Sm,150Nd,154Sm , and 166Er and 16O+232Th,238U,237Np , and 248Cm have been studied. The differences between the results obtained by using deformed surface diffuseness and those obtained by using constant surface diffuseness were noticeable. Good agreement between experimental data and theoretical calculation with deformed surface diffuseness were observed for 16O+147Sm,154Sm,166Er,238U,237Np , and 248Cm reactions. It has been observed that deformed surface diffuseness plays a significant role in heavy-ion-fusion studies.

  9. Heavy-ion collisions in a fixed target mode at the LHC beams

    NASA Astrophysics Data System (ADS)

    Kurepin, Alexey; Topilskaya, Nataliya

    2017-03-01

    The interaction of high-energy LHC beams with fixed target, including polarized nuclei targets, can expand the range of fundamental physical investigations accessible at CERN. High-intensity beam of protons and lead ions accumulated in the LHC collider allows to apply the gas-target system like the LHCb SMOG or HERMES systems. It is also possible to use the beam halo by placing in the halo the fixed target in the form of thin ribbon or use a bend crystal to extract the beam. In the extracted beam it is possible to install a polarized target. Using the proton and ion beams of the LHC with fixed targets, the data in the energy interval between maximum energy of the SPS and the nominal RHIC energy in p-A and A-A collisions could be obtained. The fixed target mode allows the intensive study of rare processes, the study of polarization phenomena, the measurements of the parameters needed to analyze the data of cosmic rays and neutrino astrophysics, detailed study of the processes of quarkonia production and suppression. The high statistics data on quarkonium production at these energies will give the possibility to clarify the mechanism of production, to investigate the importance of recombination process and the energy dependence on the phase transition of nuclear matter to the quark-gluon phase. Also the physical program includes the study of the Drell-Yan process, D-meson production, flow and spin physics.

  10. The abundance pattern of heavy elements in Sirius: Impact of modern observations (STIS) and improved Atomic data

    NASA Astrophysics Data System (ADS)

    Ramsay Cowley, Charles; Ayres, Thomas; Wahlgren, Glenn; Carpenter, Kenneth

    2015-08-01

    The abundance pattern of heavy elements in Sirius: Impact of modern observations (STIS) and improved atomic data. We determine abundances or upper limits for the 55 stable elements from copper to uranium for the A1 Vm star Sirius. The primary observational material consists of Hubble Space Telescope (HST) spectra taken with the Space Telescope Imaging Spectrograph (STIS) from the ASTRAL project (Ayres 2010, ApJS, 187, 149). We have also used archival material from COPERNICUS (retrieved from the MAST) and from HST/GHRS, as well as the ground-based Furenlid, Westin, and Kurucz Sirius Atlas (FWK). The GHRS observations were described by Wahlgren, et al. (1993, Bull. AAS, 25, 1321). We also used the monumental study of Sirius by Klaus Kohl (1964, Zs. f. Ap. 60, 115, 1964, see also 1964, Das Spektrum des Sirius, 3100 - 8863A, Kiel thesis). Abundance determinations are based on the photospheric model of Landstreet (2011, A&A, 528, 132). The atomic data base is significantly improved since the pioneering work by Sadakane (1988, PASP, 100, 811; 1991, 103, 355). The basic source was VALD3 (http://vald.inasan.ru/~vald3/php/vald.php), supplemented for all species by the essential NIST bibliographic data base (http://physics.nist.gov/cgi-bin/ASBib1/TransProbBib.cgi). We determine abundances and upper limits by synthesizing short wavelength regions around strong lines. Virtually all of the abundance/upper limit results show excesses over the solar composition of between 1 and 2 dex. This result is in general agreement with overall results for metallic line stars, though we have no information on possible severe depletions for most elements. We conclude that the mechanisms causing abundance anomalies in Sirius have not acted to produce the extreme excesses of 4 or more dex (Pt, Hg), or deficiencies (Zn) seen in many HgMn stars.CRC thanks Stefano Bagnulo for the UVESPOP Sirius spectrum. Robert Kurucz was most helpful with older Sirius UV and visual spectra.

  11. Combining Heavy Ion Radiation and Artificial MicroRNAs to Target the Homologous Recombination Repair Gene Efficiently Kills Human Tumor Cells

    SciTech Connect

    Zheng Zhiming; Wang Ping; Wang Hongyan; Zhang Xiangming; Wang Minli; Cucinotta, Francis A.; Wang Ya

    2013-02-01

    Purpose: Previously, we demonstrated that heavy ions kill more cells at the same dose than X-rays because DNA-clustered lesions produced by heavy ions affect nonhomologous end-joining (NHEJ) repair but not homologous recombination repair (HRR). We have also shown that our designed artificial microRNAs (amiRs) could efficiently target XRCC4 (an essential factor for NHEJ) or XRCC2 (an essential factor for HRR) and sensitize human tumor cells to X-rays. Based on these data, we were interested in testing the hypothesis that combining heavy ions and amiRs to target HRR but not NHEJ should more efficiently kill human tumor cells. Methods and Materials: Human tumor cell lines (U87MG, a brain tumor cell line, and A549, a lung cancer cell line) and their counterparts, overexpressed with amiR to target XRCC2, XRCC4 or both, were used in this study. Survival sensitivities were examined using a clonogenic assay after these cells were exposed to X-rays or heavy ions. In addition, these cell lines were subcutaneously injected into nude mice to form xenografts and the tumor size was compared after the tumor areas were exposed to X-rays or heavy ions. Results: Although targeting either XRCC4 (NHEJ factor) or XRCC2 (HRR factor) sensitized the human tumor cells to X-rays, in vitro and the xenograft animal model, targeting only XRCC2 but not XRCC4 sensitized the human tumor cells to heavy ions in vitro and in the xenograft animal model. Conclusions: Combining heavy ions with targeting the HRR pathway, but not the NHEJ pathway, could significantly improve the efficiency of tumor cell death.

  12. The {alpha}-induced thick-target {gamma}-ray yield from light elements

    SciTech Connect

    Heaton, R.K. |

    1994-10-01

    The {alpha}-induced thick-target {gamma}-ray yield from light elements has been measured in the energy range 5.6 MeV {le} E{sub {alpha}} {le} 10 MeV. The {gamma}-ray yield for > 2.1 MeV from thick targets of beryllium, boron nitride, sodium fluoride, magnesium, aluminum and silicon were measured using the {alpha}-particle beam from the Lawrence Berkeley Laboratories 88 in. cyclotron. The elemental yields from this experiment were used to construct the {alpha}-induced direct production {gamma}-ray spectrum from materials in the SNO detector, a large volume ultra-low background neutrino detector located in the Creighton mine near Sudbury, Canada. This background source was an order of magnitude lower than predicted by previous calculations. These measurements are in good agreement with theoretical calculations of this spectrum based on a statistical nuclear model of the reaction, with the gross high energy spectrum structure being reproduced to within a factor of two. Detailed comparison of experimental and theoretical excitation population distribution of several residual nuclei indicate the same level of agreement within experimental uncertainties.

  13. Experimental determination of particle range and dose distribution in thick targets through fragmentation reactions of stable heavy ions.

    PubMed

    Inaniwa, Taku; Kohno, Toshiyuki; Tomitani, Takehiro; Urakabe, Eriko; Sato, Shinji; Kanazawa, Mitsutaka; Kanai, Tatsuaki

    2006-09-07

    In radiation therapy with highly energetic heavy ions, the conformal irradiation of a tumour can be achieved by using their advantageous features such as the good dose localization and the high relative biological effectiveness around their mean range. For effective utilization of such properties, it is necessary to evaluate the range of incident ions and the deposited dose distribution in a patient's body. Several methods have been proposed to derive such physical quantities; one of them uses positron emitters generated through projectile fragmentation reactions of incident ions with target nuclei. We have proposed the application of the maximum likelihood estimation (MLE) method to a detected annihilation gamma-ray distribution for determination of the range of incident ions in a target and we have demonstrated the effectiveness of the method with computer simulations. In this paper, a water, a polyethylene and a polymethyl methacrylate target were each irradiated with stable (12)C, (14)N, (16)O and (20)Ne beams. Except for a few combinations of incident beams and targets, the MLE method could determine the range of incident ions R(MLE) with a difference between R(MLE) and the experimental range of less than 2.0 mm under the circumstance that the measurement of annihilation gamma rays was started just after the irradiation of 61.4 s and lasted for 500 s. In the process of evaluating the range of incident ions with the MLE method, we must calculate many physical quantities such as the fluence and the energy of both primary ions and fragments as a function of depth in a target. Consequently, by using them we can obtain the dose distribution. Thus, when the mean range of incident ions is determined with the MLE method, the annihilation gamma-ray distribution and the deposited dose distribution can be derived simultaneously. The derived dose distributions in water for the mono-energetic heavy-ion beams of four species were compared with those measured with an

  14. Bone as target organ for metals: the case of f-elements.

    PubMed

    Vidaud, Claude; Bourgeois, Damien; Meyer, Daniel

    2012-06-18

    The skeleton is a target organ for most metals. This leads to their bioaccumulation, either as storage of useful oligoelements or as a protection against damage by toxic elements. The different events leading to their accumulation in this organ, under constant remodeling, are not fully understood, nor the full subsequent impact on bone metabolism. This lack of knowledge is particularly true for lanthanides and actinides, whose use has been increasing over recent decades. These metals, known as f-elements, present chemical similarities and differences. After a comparison of the biologically relevant physicochemical properties of lanthanides and actinides, and a brief reminder of the main events of bone metabolism, this review considers the results published over the past decade regarding the interaction between bones and f-elements. Emphasis will be given to the molecular events, which constitute the basis of the most recent toxicological studies in this domain but still need further investigation. Ionic exchanges with the inorganic matrix, interactions with bone proteins, and cellular mechanism disturbances are mainly considered in this review.

  15. Recombinant botulinum neurotoxin A heavy chain-based delivery vehicles for neuronal cell targeting

    PubMed Central

    Ho, Mengfei; Chang, Li-Hsin; Pires-Alves, Melissa; Thyagarajan, Baskaran; Bloom, Jordan E.; Gu, Zhengrong; Aberle, Karla K.; Teymorian, Sasha A.; Bannai, Yuka; Johnson, Steven C.; McArdle, Joseph J.; Wilson, Brenda A.

    2011-01-01

    The long half-life of botulinum neurotoxin serotype A (BoNT/A) in cells poses a challenge in developing post-exposure therapeutics complementary to existing antitoxin strategies. Delivery vehicles consisting of the toxin heavy chain (HC), including the receptor-binding domain and translocation domain, connected to an inhibitory cargo offer a possible solution for rescuing intoxicated neurons in victims paralyzed from botulism. Here, we report the expression and purification of soluble recombinant prototype green fluorescent protein (GFP) cargo proteins fused to the entire BoNT/A-HC (residues 544–1295) in Escherichia coli with up to a 40 amino acid linker inserted between the cargo and BoNT/A-HC vehicle. We show that these GFP-HC fusion proteins are functionally active and readily taken up by cultured neuronal cells as well as by neuronal cells in mouse motor nerve endings. PMID:21051321

  16. Generation of heavy ion beams using femtosecond laser pulses in the target normal sheath acceleration and radiation pressure acceleration regimes

    NASA Astrophysics Data System (ADS)

    Petrov, G. M.; McGuffey, C.; Thomas, A. G. R.; Krushelnick, K.; Beg, F. N.

    2016-06-01

    Theoretical study of heavy ion acceleration from sub-micron gold foils irradiated by a short pulse laser is presented. Using two dimensional particle-in-cell simulations, the time history of the laser pulse is examined in order to get insight into the laser energy deposition and ion acceleration process. For laser pulses with intensity 3 × 10 21 W / cm 2 , duration 32 fs, focal spot size 5 μm, and energy 27 J, the calculated reflection, transmission, and coupling coefficients from a 20 nm foil are 80%, 5%, and 15%, respectively. The conversion efficiency into gold ions is 8%. Two highly collimated counter-propagating ion beams have been identified. The forward accelerated gold ions have average and maximum charge-to-mass ratio of 0.25 and 0.3, respectively, maximum normalized energy 25 MeV/nucleon, and flux 2 × 10 11 ions / sr . An analytical model was used to determine a range of foil thicknesses suitable for acceleration of gold ions in the radiation pressure acceleration regime and the onset of the target normal sheath acceleration regime. The numerical simulations and analytical model point to at least four technical challenges hindering the heavy ion acceleration: low charge-to-mass ratio, limited number of ions amenable to acceleration, delayed acceleration, and high reflectivity of the plasma. Finally, a regime suitable for heavy ion acceleration has been identified in an alternative approach by analyzing the energy absorption and distribution among participating species and scaling of conversion efficiency, maximum energy, and flux with laser intensity.

  17. Paired hormone response elements predict caveolin-1 as a glucocorticoid target gene.

    PubMed

    van Batenburg, Marinus F; Li, Hualing; Polman, J Annelies; Lachize, Servane; Datson, Nicole A; Bussemaker, Harmen J; Meijer, Onno C

    2010-01-21

    Glucocorticoids act in part via glucocorticoid receptor binding to hormone response elements (HREs), but their direct target genes in vivo are still largely unknown. We developed the criterion that genomic occurrence of paired HREs at an inter-HRE distance less than 200 bp predicts hormone responsiveness, based on synergy of multiple HREs, and HRE information from known target genes. This criterion predicts a substantial number of novel responsive genes, when applied to genomic regions 10 kb upstream of genes. Multiple-tissue in situ hybridization showed that mRNA expression of 6 out of 10 selected genes was induced in a tissue-specific manner in mice treated with a single dose of corticosterone, with the spleen being the most responsive organ. Caveolin-1 was strongly responsive in several organs, and the HRE pair in its upstream region showed increased occupancy by glucocorticoid receptor in response to corticosterone. Our approach allowed for discovery of novel tissue specific glucocorticoid target genes, which may exemplify responses underlying the permissive actions of glucocorticoids.

  18. Design specification for the European Spallation Source neutron generating target element

    NASA Astrophysics Data System (ADS)

    Aguilar, A.; Sordo, F.; Mora, T.; Mena, L.; Mancisidor, M.; Aguilar, J.; Bakedano, G.; Herranz, I.; Luna, P.; Magan, M.; Vivanco, R.; Jimenez-Villacorta, F.; Sjogreen, K.; Oden, U.; Perlado, J. M.; Martinez, J. L.; Bermejo, F. J.

    2017-06-01

    The paper addresses some of the most relevant issues concerning the thermal hydraulics and radiation damage of the neutron generation target to be built at the European Spallation Source as recently approved after a critical design review. The target unit consists of a set of Tungsten blocks placed inside a wheel of 2.5 m diameter which rotates at some 0.5 Hz in order to distribute the heat generated from incoming protons which reach the target in the radial direction. The spallation material elements are composed of an array of Tungsten pieces which rest on a rotating steel support (the cassette) and are distributed in a cross-flow configuration. The thermal, mechanical and radiation effects resulting from the impact of a 2 GeV proton pulse are analysed in detail as well as an evaluation of the inventory of spallation products. The current design is found to conform to specifications and found to be robust enough to deal with several accident scenarios.

  19. Fixed target project AFTER at the LHC beams for heavy ion and hadron physics

    NASA Astrophysics Data System (ADS)

    Kurepin, A. B.; Topilskaya, N. S.

    2017-09-01

    High intensity proton and lead ion beams at the LHC collider allow one to use the beam halo by placing a fixed target or a bent crystal for beam extraction. The particle energy in this case is just half that at the RHIC collider, but the luminosity exceeds the collider luminosity many times. It is also possible to install a polarized target in the extracted beam. The project AFTER is aimed at investigation of rare processes, polarization phenomena, determination of the parameters required for analysis of cosmic rays and neutrino astrophysics, detailed investigation of quarkonia production and suppression depending on the phase transition of matter to the quark-gluon phase.

  20. Coupled-cluster method for open-shell heavy-element systems with spin-orbit coupling.

    PubMed

    Cao, Zhanli; Wang, Fan; Yang, Mingli

    2017-04-07

    The coupled-cluster approach with spin-orbit coupling (SOC) included in post-self-consistent field treatment (SOC-CC) using relativistic effective core potentials is extended to spatially non-degenerate open-shell systems in this work. The unrestricted Hartree-Fock determinant corresponding to the scalar relativistic Hamiltonian is employed as the reference and the open-shell SOC-CC approach is implemented at the CC singles and doubles (CCSD) level as well as at the CCSD level augmented by a perturbative treatment of triple excitations (CCSD(T)). Due to the breaking of time-reversal symmetry and spatial symmetry, this open-shell SOC-CC approach is rather expensive compared with the closed-shell SOC-CC approach. The open-shell SOC-CC approach is applied to some open-shell atoms and diatomic molecules with s(1), p(3), σ(1), or π(2) configuration. Our results indicate that rather accurate results can be achieved with the open-shell SOC-CCSD(T) approach for these systems. Dissociation energies for some closed-shell molecules containing heavy IIIA or VIIA atoms are also calculated using the closed-shell SOC-CC approach, where energies of the IIIA or VIIA atoms are obtained from those of the closed-shell ions and experimental ionization potentials or electron affinities. SOC-CCSD(T) approach affords reliable dissociation energies for these molecules. Furthermore, scalar-relativistic CCSD(T) approach with the same strategy can also provide reasonable dissociation energies for the 5th row IIIA or VIIA molecules, while the error becomes pronounced for the 6th row elements.

  1. Coupled-cluster method for open-shell heavy-element systems with spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Cao, Zhanli; Wang, Fan; Yang, Mingli

    2017-04-01

    The coupled-cluster approach with spin-orbit coupling (SOC) included in post-self-consistent field treatment (SOC-CC) using relativistic effective core potentials is extended to spatially non-degenerate open-shell systems in this work. The unrestricted Hartree-Fock determinant corresponding to the scalar relativistic Hamiltonian is employed as the reference and the open-shell SOC-CC approach is implemented at the CC singles and doubles (CCSD) level as well as at the CCSD level augmented by a perturbative treatment of triple excitations (CCSD(T)). Due to the breaking of time-reversal symmetry and spatial symmetry, this open-shell SOC-CC approach is rather expensive compared with the closed-shell SOC-CC approach. The open-shell SOC-CC approach is applied to some open-shell atoms and diatomic molecules with s1, p3, σ1, or π2 configuration. Our results indicate that rather accurate results can be achieved with the open-shell SOC-CCSD(T) approach for these systems. Dissociation energies for some closed-shell molecules containing heavy IIIA or VIIA atoms are also calculated using the closed-shell SOC-CC approach, where energies of the IIIA or VIIA atoms are obtained from those of the closed-shell ions and experimental ionization potentials or electron affinities. SOC-CCSD(T) approach affords reliable dissociation energies for these molecules. Furthermore, scalar-relativistic CCSD(T) approach with the same strategy can also provide reasonable dissociation energies for the 5th row IIIA or VIIA molecules, while the error becomes pronounced for the 6th row elements.

  2. Structural differences between light and heavy rare earth element binding chlorophylls in naturally grown fern: Dicranopteris linearis.

    PubMed

    Wei, Zhenggui; Hong, Fashui; Yin, Ming; Li, Huixin; Hu, Feng; Zhao, Guiwen; Wong, Jonathan Woonchung

    2005-09-01

    Chloroplasts and chlorophylls were isolated from the leaves of Dicranopteris linearis, a natural perennial fern sampled at rare earth element (REE) mining areas in the South-Jiangxi region (southern China). The inductively coupled plasma-mass spectrometry (ICP-MS) results indicated that REEs were present in the chloroplasts and chlorophylls of D. linearis. The in vivo coordination environment of light REE (lanthanum) or heavy REE (yttrium) ions in D. linearis chlorophyll-a was determined by the extended X-ray absorption fine structure (EXAFS). Results revealed that there were eight nitrogen atoms in the first coordination shell of the lanthanum atom, whereas there were four nitrogen atoms in the first coordination shell of yttrium. It was postulated that the lanthanum-chlorophyll-a complex might have a double-layer sandwich-like structure, but yttrium-binding chlorophyll-a might be in a single-layer form. Because the content of REE-binding chlorophylls in D. linearis chlorophylls was very low, it is impossible to obtain structural characteristics of REE-binding chlorophylls by direct analysis of the Fourier transform infrared (FTIR) and ultraviolet (UV)-visible spectra of D. linearis chlorophylls. In order to acquire more structural information of REE-binding chlorophyll-a in D. linearis, lanthanum - and yttrium-chlorophyll-a complexes were in vitro synthesized in acetone solution. Element analyses and EXAFS results indicated that REE ions (lanthanum or yttrium) of REE-chlorophyll-a possessed the same coordination environment whether in vivo or in vitro. The FTIR spectra of the REE-chlorophyll-a complexes indicated that REEs were bound to the porphyrin rings of chlorophylls. UV-visible results showed that the intensity ratios of Soret to the Q-band of REE-chlorophyll-a complexes were higher than those of standard chlorophyll-a and pheophytin-a, indicating that REE-chlorophyll-a might have a much stronger ability to absorb the ultraviolet light. The MCD spectrum in

  3. Accumulation and tissue distribution of heavy metals and essential elements in loggerhead turtles (Caretta caretta) from Spanish Mediterranean coastline of Murcia.

    PubMed

    Jerez, Silvia; Motas, Miguel; Cánovas, Régulo Angel; Talavera, Jesús; Almela, Ramón Miguel; Del Río, Alejandro Bayón

    2010-01-01

    Sea turtles are of increasing interest as potential bioindicators of the heavy metal pollution in marine ecosystems. In the present work, concentrations of heavy metals and essential elements (As, Cd, Hg, Pb, Se, Zn) in different organs and tissues (liver, kidney, muscle, bone, blood, central nervous system and skin) of loggerhead sea turtles (Caretta caretta) were determined from stranded animals found along the Spanish Mediterranean coastlines of Murcia. Relatively high average levels of As (skin: 52.13 microg g(-1) dry weight; muscle: 40.95 microg g(-1) dry weight), and especially high individual levels of Zn in muscle tissue (1002.4 microg g(-1) dry weight) were detected. Furthermore, a significant degree of organotrophism of Cd was observed in kidney tissue. The concentrations detected, the distribution among the tissues and the differences observed between juvenile and adult specimens are generally compatible with chronic exposure to the elements studied, whilst levels produced by acute exposure were ruled out.

  4. [MONITORING OF THE CONTENT OF HEAVY METALS AND ELEMENTS IN THE SNOW COVER IN AGRICULTURAL SOILS AT THE TERRITORY OF THE MOSCOW REGION].

    PubMed

    Ermakov, A A; Karpova, E A; Malysheva, A G; Mikhaylova, R I; Ryzhova, I N

    2015-01-01

    The monitoring of snow cover pollution by heavy metals and elements (zinc, copper, lead, cadmium, arsenic, nickel, chromium, strontium, manganese, fluorine, lithium) was performed in 20 districts of the Moscow region in 2009, 2012 and 2013. The assessment of the levels of contamination by heavy metals and elements was given by means of comparison of them with the average values in the snow cover near Moscow in the end of the last century and in some areas of the world, that no exposed to technological environmental impact. 7 districts of Moscow region were characterized by a high content of lead and cadmium in the snow water. It requires the control of water, soil and agricultural products pollution.

  5. Cosmic ray heavy ion LET mapping for aluminum, silicon, and tissue targets

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Barth, J. M.; Jordan, T. M.

    1987-01-01

    Linear energy transfer (LET) values in aluminum, silicon, and tissue targets have been calculated for 31 galactic cosmic ray ion species in eight different units. The values are described for single event upset (SEU) effect assessments or radiobiological evaluations. The data are presented in graphical and tabular form.

  6. Reaction dynamics induced by the radioactive ion beam {sup 7}Be on medium-mass and heavy targets

    SciTech Connect

    Mazzocco, M. Stefanini, C.; Strano, E.; Torresi, D.; Lay, J. A.; Molini, P.; Soramel, F.; Boiano, A.; Parascandolo, C.; Pierroutsakou, D.; Di Meo, P.; Boiano, C.; La Commara, M.; Sandoli, M.; Silvestri, R.; Manea, C.; Nicoletto, M.; Acosta, L.; Fernandez-Garcia, J. P.; Glodariu, T.; and others

    2015-10-15

    We studied the reaction dynamics induced at Coulomb barrier energies by the weakly-bound Radioactive Ion Beam {sup 7}Be (S{sub α} = 1.586 MeV) on medium-mass ({sup 58}Ni) and heavy ({sup 208}Pb) targets. The experiments were performed at INFN-LNL (Italy), where a 2-3×10{sup 5} pps {sup 7}Be secondary beam was produced with the RIB in-flight facility EXOTIC. Charged reaction products were detected by means of high-granularity silicon detectors in rather wide angular ranges. The contribution presents an up-to-date status of the data analysis and theoretical interpretation for both systems.

  7. Simulation of Intense Beams and Targets for Heavy-Ion-Fusion Science (HEDLP / Inertial Fusion Energy)

    SciTech Connect

    Friedman, Alex; Barnard, John J.; Cohen, Ron H.; Dorf, Mikhail; Eder, David; Grote, Dave P.; Lund, Steve M.; Sharp, William M.; Henestroza, Enrique; Lee, Ed P.; Vay, Jean -Luc; Davidson, Ron C.; Kaganovich, Igor D.; Qin, Hong; Startsev, Ed; Fagnan, Kirsten; Koniges, Alice; Bertozzi, Andrea

    2010-08-26

    Our principal goals, and activities in support of those goals, over the next five years are as follows: (1) Optimize the properties of the NDCX-II beam for each class of target experiments; achieve quantitative agreement with measurements; develop improved machine configurations and operating points. To accomplish these goals, we plan to use Warp to simulate NDCX-II from source to target, in full kinetic detail, including first-principles modeling of beam neutralization by plasma. The output from an ensemble of Warp runs (representing shot-to-shot variations) will be used as input to target simulations using ALE-AMR on NERSC, and other codes. (2) Develop enhanced versions of NDCX-II (the machine is designed to be extensible and reconfigurable), and carry out studies to define a next-step ion beam facility. To accomplish these goals, much of the work will involve iterative optimization employing Warp runs that assume ideal beam neutralization downstream of the accelerator. (3) Carry out detailed target simulations in the Warm Dense Matter regime using the ALE-AMR code, including surface tension effects, liquid-vapor coexistence, and accurate models of both the driving beam and the target geometry. For this we will need to make multiple runs (to capture shot-to-shot variations), and to both develop and employ synthetic diagnostics (to enable comparison with experiments). The new science that will be revealed is the physics of the transition from the liquid to vapor state of a volumetrically superheated material, wherein droplets are formed, and wherein phase transitions, surface tension and hydrodynamics all play significant roles in the dynamics. These simulations will enable calculations of equation of state and other material properties, and will also be of interest for their illumination of the science of droplet formation.

  8. Hydrogen plasma dynamics in the spherical theta pinch plasma target for heavy ion stripping

    SciTech Connect

    Loisch, G.; Jacoby, J.; Xu, G.; Blazevic, A.; Cihodariu-Ionita, B.

    2015-05-15

    Due to the superior ability of dense and highly ionised plasmas to ionise penetrating heavy ion beams to degrees beyond those reachable by common gas strippers, many experiments have been performed to find suitable plasma generators for this application. In the field of gas discharges, mainly z-pinch devices have been investigated so far, which are known to be limited by the nonlinear focusing effects of the plasma columns sustaining current and by electrode erosion. The spherical theta pinch has therefore been proposed as a substitution for the z-pinch, promising progress by inductive rather than capacitive coupling and displacement of the outer magnetic field by the dense, diamagnetic discharge plasma. As yet mainly experiments with argon/hydrogen mixture gas have been performed, which is not suitable for the application as a plasma stripper, this paper describes the first detailed analysis of the plasma parameters and dynamics of a hydrogen plasma created by the spherical theta pinch. These include the time integrated and time resolved electron density, the dynamics of the plasma in the discharge vessel, the comparison with the argon dominated plasma, and an outlook to reachable characteristics with similar devices.

  9. Br-rich tips of calcified crab claws are less hard but more fracture resistant: a comparison of mineralized and heavy-element biological materials.

    PubMed

    Schofield, Robert M S; Niedbala, Jack C; Nesson, Michael H; Tao, Ye; Shokes, Jacob E; Scott, Robert A; Latimer, Matthew J

    2009-06-01

    We find that the spoon-like tips of the chelipeds (large claws) of the crab Pachygrapsus crassipes differ from the rest of the claw in that they are not calcified, but instead contain about 1% bromine--thus they represent a new example of a class of structural biological materials that contain heavy elements such as Zn, Mn, Fe, Cu, and Br bound in an organic matrix. X-ray absorption spectroscopy data suggest that the bromine is bound to phenyl rings, possibly in tyrosine. We measure a broad array of mechanical properties of a heavy-element biological material for the first time (abrasion resistance, coefficient of kinetic friction, energy of fracture, hardness, modulus of elasticity and dynamic mechanical properties), and we make a direct comparison with a mineralized tissue. Our results suggest that the greatest advantage of bromine-rich cuticle over calcified cuticle is resistance to fracture (the energy of fracture is about an order of magnitude greater than for calcified cuticle). The greatest advantage relative to unenriched cuticle, represented by ant mandible cuticle, is a factor of about 1.5 greater hardness and modulus of elasticity.The spoon-like tips gain additional fracture resistance from the orientation of the constituent laminae and from the viscoelasticity of the material. We suggest that fracture resistance is of greater importance in smaller organisms, and we speculate that one function of heavy elements in structural biological materials is to reduce molecular resonant frequencies and thereby increase absorption of energy from impacts.

  10. Br-rich tips of calcified crab claws are less hard but more fracture resistant: a comparison of biomineralized and heavy-element biomaterials

    PubMed Central

    Schofield, Robert M. S.; Niedbala, Jack C.; Nesson, Michael H.; Tao, Ye; Shokes, Jacob E.; Scott, Robert A.; Latimer, Matthew J.

    2009-01-01

    We find that the spoon-like tips of the chelipeds (large claws) of the crab Pachygrapsus crassipes differ from the rest of the claw in that they are not calcified, but instead contain about 1% bromine – thus they represent a new example of a class of structural biomaterials that contain heavy elements such as Zn, Mn, Fe, Cu, and Br bound in an organic matrix. X-ray absorption spectroscopy data suggest that the bromine is bound to phenyl rings, possibly in tyrosine. We measure a broad array of mechanical properties of a heavy-element biomaterial (abrasion resistance, coefficient of kinetic friction, energy of fracture, hardness, modulus of elasticity and dynamic mechanical properties) for the first time, and we make a direct comparison with a mineralized tissue. Our results suggest that the greatest advantage of bromine-rich cuticle over calcified cuticle is resistance to fracture (the energy of fracture is about an order of magnitude greater than for calcified cuticle). The greatest advantage relative to unenriched cuticle, represented by ant mandible cuticle, is a factor of about 1.5 greater hardness and modulus of elasticity. The spoon-like tips gain increased fracture resistance from the orientation of the constituent laminae and from the viscoelasticity of the materials. We suggest that fracture resistance is of greater importance in smaller organisms, and we speculate that one function of heavy elements in mechanical biomaterials is to reduce molecular resonant frequencies and thereby increase absorption of energy from impacts. PMID:19422071

  11. Heavy particle atomic collisions in astrophysics: Beyond H and He targets

    SciTech Connect

    Stancil, P.C.; Krstic, P.S.; Schultz, D.R.

    1998-06-01

    The physical conditions relating to the emission of x-rays from Jovian and cometary atmospheres and to supernova ejecta are briefly described. Emphasis is placed on elucidating the relevance and importance of atomic collision processes, the availability of data, and the outstanding data needs for modeling these environments. Some preliminary theoretical studies of electron capture for important collisions systems, involving molecular and atomic metal targets, are presented.

  12. Linear microfocus bremsstrahlung generated in light and heavy narrow targets in B-18 betatron

    NASA Astrophysics Data System (ADS)

    Rychkov, M. M.; Kaplin, V. V.; Malikov, E. L.; Smolyanskiy, V. A.; Stepanov, I. B.; Lutsenko, A. S.; Gentsel'man, V.; Vas'kovskii, I. K.

    2017-08-01

    The first results of studying the properties of X- and G-ray beams generated at the grazing incidence of 18-MeV electrons with the 50 and 8-μm-thick Si crystals and a 13-μm-thick Ta foil of 4 mm in length along the electron beam are presented. The target has been placed in a goniometer inside the chamber of a B-18 betatron. The results exhibit strong changes in the angular distribution of radiation at the variation of the orientation of the target. This effect is not observed in the case of the normal incidence of electrons on the surface of a thin target. Images of a reference microstructure have been obtained with a high resolution of details of the microstructure owing to the smallness of the source of radiation. The dependence of the contrast of an image on the position of the microstructure in the radiation cone has been demonstrated, which is determined by the change in the effective size of the radiation source when the emission angle of the source is changed.

  13. Hotspots for Vitamin-Steroid-Thyroid Hormone Response Elements Within Switch Regions of Immunoglobulin Heavy Chain Loci Predict a Direct Influence of Vitamins and Hormones on B Cell Class Switch Recombination.

    PubMed

    Hurwitz, Julia L; Penkert, Rhiannon R; Xu, Beisi; Fan, Yiping; Partridge, Janet F; Maul, Robert W; Gearhart, Patricia J

    2016-03-01

    Vitamin A deficiencies are common throughout the world and have a significant negative influence on immune protection against viral infections. Mouse models demonstrate that the production of IgA, a first line of defense against viruses at mucosal sites, is inhibited in the context of vitamin A deficiency. In vitro, the addition of vitamin A to activated B cells can enhance IgA expression, but downregulate IgE. Previous reports have demonstrated that vitamin A modifies cytokine patterns, and in so doing may influence antibody isotype expression by an indirect mechanism. However, we have now discovered hundreds of potential response elements among Sμ, Sɛ, and Sα switch sites within immunoglobulin heavy chain loci. These hotspots appear in both mouse and human loci and include targets for vitamin receptors and related proteins (e.g., estrogen receptors) in the nuclear receptor superfamily. Full response elements with direct repeats are relatively infrequent or absent in Sγ regions although half-sites are present. Based on these results, we pose a hypothesis that nuclear receptors have a direct effect on the immunoglobulin heavy chain class switch recombination event. We propose that vitamin A may alter S site accessibility to activation-induced deaminase and nonhomologous end-joining machinery, thereby influencing the isotype switch, antibody production, and protection against viral infections at mucosal sites.

  14. Targeting the (3.8-4.0 Ga) Impactors: Siderophile Element Signatures of Lunar Impact Melts

    NASA Astrophysics Data System (ADS)

    Bennett, V.; Norman, M.; Ryder, G.

    2001-12-01

    Significant gaps remain in our understanding of the early impact history of the Earth and Moon, and their influence on geologic and biologic development. Outstanding controversies include whether or not the Moon, and by inference the early Earth, was hit by an unusually heavy "terminal cataclysm" of collisions during the period 3.8 to 4.0 Ga, and the number of large impact events represented by lunar samples. Coincidentally or not, the large nearside lunar basins are almost identical in age with the oldest terrestrial rocks, and are therefore relevant for consideration of the possible role of impacts in shaping the terrestrial continents and early life environments. To improve our understanding of the impact history of the Moon and to provide new information about the types of planetesimals that were involved in the early impact history of the inner Solar System, we measured the concentrations of highly siderophile elements (HSE: Re, Ir, Pt, Pd, Ru) in a suite of Apollo 17 impact melt breccias using high precision ID-ICPMS methods. These breccias all have poikilitic textures, relatively mafic bulk compositions, and high levels of incompatible trace elements and all likely represent ejecta from the Serenitatis basin. Ar-Ar ages are consistent with the formation of these breccias in a single impact event at 3893 +/- 9 Ma. HSE from 11 representative samples have W-shaped patterns on CI-normalized diagrams, with enrichments in Re, Ru and Pd relative to Ir and Pt, and absolute abundances ranging from \\sim0.5 to 4% of CI reference values. Stronger depletions of Ir and Pt relative to Re, Ru, and Pd are correlated with decreasing HSE concentrations. The samples with the highest HSE concentrations have patterns that are identical to those of EH chondrites, but the patterns become increasingly less diagnostic of meteorite group with decreasing concentrations. The systematic variation of HSE patterns with decreasing concentration suggests that simple chemical fingerprints of

  15. Halbach arrays consisting of cubic elements optimised for high field gradients in magnetic drug targeting applications.

    PubMed

    Barnsley, Lester C; Carugo, Dario; Owen, Joshua; Stride, Eleanor

    2015-11-07

    A key challenge in the development of magnetic drug targeting (MDT) as a clinically relevant technique is designing systems that can apply sufficient magnetic force to actuate magnetic drug carriers at useful tissue depths. In this study an optimisation routine was developed to generate designs of Halbach arrays consisting of multiple layers of high grade, cubic, permanent magnet elements, configured to deliver the maximum pull or push force at a position of interest between 5 and 50 mm from the array, resulting in arrays capable of delivering useful magnetic forces to depths past 20 mm. The optimisation routine utilises a numerical model of the magnetic field and force generated by an arbitrary configuration of magnetic elements. Simulated field and force profiles of optimised arrays were evaluated, also taking into account the forces required for assembling the array in practice. The resultant selection for the array, consisting of two layers, was then constructed and characterised to verify the simulations. Finally the array was utilised in a set of in vitro experiments to demonstrate its capacity to separate and retain microbubbles loaded with magnetic nanoparticles against a constant flow. The optimised designs are presented as light-weight, inexpensive options for applying high-gradient, external magnetic fields in MDT applications.

  16. A P Element Chimera Containing Captured Genomic Sequences Was Recovered at the Vestigial Locus in Drosophila following Targeted Transposition

    PubMed Central

    Heslip, T. R.; Williams, J. A.; Bell, J. B.; Hodgetts, R. B.

    1992-01-01

    A P element carrying the Dopa decarboxylase gene, P[Ddc], was targeted into vg(21), a cryptic P element induced mutant allele of the vestigial (vg) locus. The resulting allele, vg(28w), contained the expected P[Ddc] plus an additional 9.5 kb of DNA, captured from elsewhere on chromosome II. Reversion of the vg(28w) mutant allele demonstrated that the entire insert can excise but cannot reinsert at an appreciable frequency. We explain the targeted transposition as the repair of a double stranded gap, created by the excision of the P element at vg(21), and suggest that the formation of chimeric elements may be an important component of P element dependent genomic instability. PMID:1325388

  17. Do pharmacological approaches that prevent opioid tolerance target different elements in the same regulatory machinery?

    PubMed

    Garzón, Javier; Rodríguez-Muñoz, María; Sánchez-Blázquez, Pilar

    2008-06-01

    In the nervous system, the interaction of opioids like heroin and morphine with the G protein-coupled Mu-opioid receptor (MOR) provokes the development of tolerance to these opioids, as well as physical dependence. Tolerance implies that higher doses of these drugs must be consumed in order to obtain an equivalent sensation, a situation that contributes notably to the social problems surrounding recreational opioid abuse. The mechanisms that promote opioid tolerance involve a series of adaptive changes in the MOR and in the post-receptor signalling elements. Pharmacological studies have consistently identified a number of signalling proteins relevant to morphine-induced tolerance, including the delta-opioid receptor (DOR), protein kinase C (PKC), protein kinase A (PKA), calcium/calmodulin-dependent kinase II (CaMKII), nitric oxide synthase (NOS), N-methyl-D-aspartate acid glutamate receptors (NMDAR), and regulators of G-signalling (RGS) proteins. Thus, it is feasible that these treatments which diminish morphine tolerance target distinct elements within the same regulatory machinery. In this scheme, the signals originated at the agonist-activated MORs would be recognised by elements such as the NMDARs, which in turn exert a negative feedback on MOR-evoked signalling. This process involves DOR regulation of MORs, MOR-induced activation of NMDARs (probably via the regulation of Src, recruiting PKC and Galpha subunits) and the NMDAR-mediated activation of CaMKII. The active CaMKII promotes the sequestering of morphine-activated Gbetagamma dimers by phosducin-like proteins (PhLP) and of Galpha subunits by RGS proteins and tolerance to opioids like morphine develops. Future efforts to study these phenomena should focus on fitting additional pieces into this puzzle in order to fully define the mechanism underlying the desensitization of MORs in neural cells.

  18. Managing Inventories of Heavy Actinides

    SciTech Connect

    Wham, Robert M; Patton, Bradley D

    2011-01-01

    The Department of Energy (DOE) has stored a limited inventory of heavy actinides contained in irradiated targets, some partially processed, at the Savannah River Site (SRS) and Oak Ridge National Laboratory (ORNL). The 'heavy actinides' of interest include plutonium, americium, and curium isotopes; specifically 242Pu and 244Pu, 243Am, and 244/246/248Cm. No alternate supplies of these heavy actinides and no other capabilities for producing them are currently available. Some of these heavy actinide materials are important for use as feedstock for producing heavy isotopes and elements needed for research and commercial application. The rare isotope 244Pu is valuable for research, environmental safeguards, and nuclear forensics. Because the production of these heavy actinides was made possible only by the enormous investment of time and money associated with defense production efforts, the remaining inventories of these rare nuclear materials are an important part of the legacy of the Nuclear Weapons Program. Significant unique heavy actinide inventories reside in irradiated Mark-18A and Mark-42 targets at SRS and ORNL, with no plans to separate and store the isotopes for future use. Although the costs of preserving these heavy actinide materials would be considerable, for all practical purposes they are irreplaceable. The effort required to reproduce these heavy actinides today would likely cost billions of dollars and encompass a series of irradiation and chemical separation cycles for at least 50 years; thus, reproduction is virtually impossible. DOE has a limited window of opportunity to recover and preserve these heavy actinides before they are disposed of as waste. A path forward is presented to recover and manage these irreplaceable National Asset materials for future use in research, nuclear forensics, and other potential applications.

  19. Functional evolution of the p53 regulatory network through its target response elements

    PubMed Central

    Jegga, Anil G.; Inga, Alberto; Menendez, Daniel; Aronow, Bruce J.; Resnick, Michael A.

    2008-01-01

    Transcriptional network evolution is central to the development of complex biological systems. Networks can evolve through variation of master regulators and/or by changes in regulation of genes within networks. To gain insight into meaningful evolutionary differences in large networks, it is essential to address the functional consequences of sequence differences in response elements (REs) targeted by transcription factors. Using a combination of custom bioinformatics and multispecies alignment of promoter regions, we investigated the functional evolution of REs in terms of responsiveness to the sequence-specific transcription factor p53, a tumor suppressor and master regulator of stress responses. We identified REs orthologous to known p53 targets in human and rodent cells or alternatively REs related to the established p53 consensus. The orthologous REs were assigned p53 transactivation capabilities based on rules determined from model systems, and a functional heat map was developed to visually summarize conservation of sequence and relative level of responsiveness to p53 for 47 REs in 14 species. Individual REs exhibited marked differences in transactivation potentials and widespread evolutionary turnover. Functional differences were often not predicted from consensus sequence evaluations. Of the established human p53 REs analyzed, 91% had sequence conservation in at least one nonprimate species compared with 67.5% for functional conservation. Surprisingly, there was almost no conservation of functional REs for genes involved in DNA metabolism or repair between humans and rodents, suggesting important differences in p53 stress responses and cancer development. PMID:18187580

  20. Elemental conservation units: communicating extinction risk without dictating targets for protection.

    PubMed

    Wood, Chris C; Gross, Mart R

    2008-02-01

    Conservation biologists mostly agree on the need to identify and protect biodiversity below the species level but have not yet resolved the best approach. We addressed 2 issues relevant to this debate. First, we distinguished between the abstract goal of preserving the maximum amount of unique biodiversity and the pragmatic goal of minimizing the loss of ecological goods and services given that further loss of biodiversity seems inevitable. Second, we distinguished between the scientific task of assessing extinction risk and the normative task of choosing targets for protection. We propose that scientific advice on extinction risk be given at the smallest meaningful scale: the elemental conservation unit (ECU). An ECU is a demographically isolated population whose probability of extinction over the time scale of interest (say 100 years) is not substantially affected by natural immigration from other populations. Within this time frame, the loss of an ECU would be irreversible without human intervention. Society's decision to protect an ECU ought to reflect human values that have social, economic, and political dimensions. Scientists can best inform this decision by providing advice about the probability that an ECU will be lost and the ecological and evolutionary consequences of that loss in a form that can be integrated into landscape planning. The ECU approach provides maximum flexibility to decision makers and ensures that the scientific task of assessing extinction risk informs, but remains distinct from, the normative social challenge of setting conservation targets.

  1. The application of neutron radioscopy to lithium-aluminum alloy target elements

    SciTech Connect

    Antal, J.J.; Marotta, A.S. . Materials Technology Lab.); Salaymeh, S.R.; Varallo, T.P. )

    1989-01-01

    We have shown that neutron radioscopy is very useful in locating the position of a Li-Al alloy core enriched in lithium-6 in tubular aluminum target elements. The alloy core is displaced during a forming process and its location must be redetermined before processing can be completed. The Army's low-flux mobile neutron radioscopy system was employed in these studies as a model system for possible on-line, in-plant use. A series of core end sections of target tubes containing from 0.1 to 4.6 grams of lithium-6 per foot of length were examined radioscopically with thermal neutrons. The system was able to determine the extent of lithium alloy core from the highest concentrations down to about 0.2 grams of lithium-6 per ft within one minute of data collection time. A marked loss of sensitivity below this level could be recovered by providing higher geometrical resolution in the images obtained or by using image enhancement techniques. Film radiography was used to verify the accuracy of radioscopic determinations at the lowest lithium concentrations. 7 refs., 6 figs., 1 tab.

  2. Optimization of Morpholino Antisense Oligonucleotides Targeting the Intronic Repressor Element1 in Spinal Muscular Atrophy.

    PubMed

    Osman, Erkan Y; Washington, Charles W; Kaifer, Kevin A; Mazzasette, Chiara; Patitucci, Teresa N; Florea, Kyra M; Simon, Madeline E; Ko, Chien-Ping; Ebert, Allison D; Lorson, Christian L

    2016-09-01

    Loss of Survival Motor Neuron-1 (SMN1) causes Spinal Muscular Atrophy, a devastating neurodegenerative disease. SMN2 is a nearly identical copy gene; however SMN2 cannot prevent disease development in the absence of SMN1 since the majority of SMN2-derived transcripts are alternatively spliced, encoding a truncated, unstable protein lacking exon 7. Nevertheless, SMN2 retains the ability to produce low levels of functional protein. Previously we have described a splice-switching Morpholino antisense oligonucleotide (ASO) sequence that targets a potent intronic repressor, Element1 (E1), located upstream of SMN2 exon 7. In this study, we have assessed a novel panel of Morpholino ASOs with the goal of optimizing E1 ASO activity. Screening for efficacy in the SMNΔ7 mouse model, a single ASO variant was more active in vivo compared with the original E1(MO)-ASO. Sequence variant eleven (E1(MOv11)) consistently showed greater efficacy by increasing the lifespan of severe Spinal Muscular Atrophy mice after a single intracerebroventricular injection in the central nervous system, exhibited a strong dose-response across an order of magnitude, and demonstrated excellent target engagement by partially reversing the pathogenic SMN2 splicing event. We conclude that Morpholino modified ASOs are effective in modifying SMN2 splicing and have the potential for future Spinal Muscular Atrophy clinical applications.

  3. Target enrichment of ultraconserved elements from arthropods provides a genomic perspective on relationships among Hymenoptera.

    PubMed

    Faircloth, Brant C; Branstetter, Michael G; White, Noor D; Brady, Seán G

    2015-05-01

    Gaining a genomic perspective on phylogeny requires the collection of data from many putatively independent loci across the genome. Among insects, an increasingly common approach to collecting this class of data involves transcriptome sequencing, because few insects have high-quality genome sequences available; assembling new genomes remains a limiting factor; the transcribed portion of the genome is a reasonable, reduced subset of the genome to target; and the data collected from transcribed portions of the genome are similar in composition to the types of data with which biologists have traditionally worked (e.g. exons). However, molecular techniques requiring RNA as a template, including transcriptome sequencing, are limited to using very high-quality source materials, which are often unavailable from a large proportion of biologically important insect samples. Recent research suggests that DNA-based target enrichment of conserved genomic elements offers another path to collecting phylogenomic data across insect taxa, provided that conserved elements are present in and can be collected from insect genomes. Here, we identify a large set (n = 1510) of ultraconserved elements (UCEs) shared among the insect order Hymenoptera. We used in silico analyses to show that these loci accurately reconstruct relationships among genome-enabled hymenoptera, and we designed a set of RNA baits (n = 2749) for enriching these loci that researchers can use with DNA templates extracted from a variety of sources. We used our UCE bait set to enrich an average of 721 UCE loci from 30 hymenopteran taxa, and we used these UCE loci to reconstruct phylogenetic relationships spanning very old (≥220 Ma) to very young (≤1 Ma) divergences among hymenopteran lineages. In contrast to a recent study addressing hymenopteran phylogeny using transcriptome data, we found ants to be sister to all remaining aculeate lineages with complete support, although this result could be explained by

  4. Rapid screening of heavy metals and trace elements in environmental samples using portable X-ray fluorescence spectrometer, A comparative study

    PubMed Central

    McComb, Jacqueline Q.; Rogers, Christian; Han, Fengxiang X.; Tchounwou, Paul B.

    2014-01-01

    With industrialization, great amounts of trace elements and heavy metals have been excavated and released on the surface of the earth and dissipated into the environments. Rapid screening technology for detecting major and trace elements as well as heavy metals in variety of environmental samples is most desired. The objectives of this study were to determine the detection limits, accuracy, repeatability and efficiency of a X-ray fluorescence spectrometer (Niton XRF analyzer) in comparison with the traditional analytical methods, inductively coupled plasma optical emission spectrometer (ICP-OES) and inductively coupled plasma optical emission spectrometer (ICP-MS) in screening of major and trace elements of environmental samples including estuary soils and sediments, contaminated soils, and biological samples. XRF is a fast and non-destructive method in measuring the total concentration of multi--elements simultaneously. Contrary to ICP-OES and ICP-MS, XRF analyzer is characterized by the limited preparation required for solid samples, non-destructive analysis, increased total speed and high throughout, the decreased production of hazardous waste and the low running costs as well as multi-elemental determination and portability in the fields. The current comparative study demonstrates that XRF is a good rapid non-destructive method for contaminated soils, sediments and biological samples containing higher concentrations of major and trace elements. Unfortunately, XRF does not have sensitive detection limits of most major and trace elements as ICP-OES or ICP-MS but it may serve as a rapid screening tool for locating hot spots of uncontaminated field soils and sediments. PMID:25861136

  5. Concentrations of toxic heavy metals and trace elements in raw milk of Simmental and Holstein-Friesian cows from organic farm.

    PubMed

    Pilarczyk, Renata; Wójcik, Jerzy; Czerniak, Paweł; Sablik, Piotr; Pilarczyk, Bogumiła; Tomza-Marciniak, Agnieszka

    2013-10-01

    Concentrations of toxic heavy metals (cadmium (Cd), lead (Pb)) and major nutritional and trace elements (Ca, Mg, P, Cu, Fe, Mn, Se, Zn) were analyzed in the milk of Simmental (n = 20) and Holstein-Friesian (n = 20) cows from an organic farm. Elements were determined using inductively coupled plasma emission atomic spectrometry. The conducted research showed that the milk of Simmental cows was characterized by the more advantageous mineral composition and lower concentration of noxious heavy metals compared to the milk of Holstein-Friesian cows. In the milk of Simmental cows, significantly lower concentrations of Pb and Cd (P < 0.001) and Cu (P < 0.05) and significantly higher concentrations of Fe and Mg (P < 0.05) as well as nonsignificantly higher concentrations of Ca, Mn, and Se were found. In the milk of both breeds, very low Cu concentrations were recorded. The higher-than-recommended concentration of Pb in milk was also found. In the milk of both breeds, the significant positive correlations between concentrations of the following elements were observed: Pb-Cd, Pb-Se, Cd-Se, Cd-Mn, Zn-Cu, Zn-P, Ca-P, Ca-Mg, and Mg-P. The correlations between other elements within each of the analyzed breeds separately were also found.

  6. A possible aid in targeted insertion of large DNA elements by CRISPR/Cas in mouse zygotes.

    PubMed

    Nakao, Harumi; Harada, Takeshi; Nakao, Kazuki; Kiyonari, Hiroshi; Inoue, Kenichi; Furuta, Yasuhide; Aiba, Atsu

    2016-02-01

    The CRISPR/Cas system has rapidly emerged recently as a new tool for genome engineering, and is expected to allow for controlled manipulation of specific genomic elements in a variety of species. A number of recent studies have reported the use of CRISPR/Cas for gene disruption (knockout) or targeted insertion of foreign DNA elements (knock-in). Despite the ease of simple gene knockout and small insertions or nucleotide substitutions in mouse zygotes by the CRISPR/Cas system, targeted insertion of large DNA elements remains an apparent challenge. Here the generation of knock-in mice with successful targeted insertion of large donor DNA elements ranged from 3.0 to 7.1 kb at the ROSA26 locus using the CRISPR/Cas system was achieved. Multiple independent knock-in founder mice were obtained by injection of hCas9 mRNA/sgRNA/donor vector mixtures into the cytoplasm of C57BL/6N zygotes when the injected zygotes were treated with an inhibitor of actin polymerization, cytochalasin. Successful germ line transmission of three of these knock-in alleles was also confirmed. The results suggested that treatment of zygotes with actin polymerization inhibitors following microinjection could be a viable method to facilitate targeted insertion of large DNA elements by the CRISPR/Cas system, enabling targeted knock-in readily attainable in zygotes.

  7. Laser Resonance Ionization Spectroscopy of the Lanthanides Tb, Dy and Ho as Homologues to Actinides and Super Heavy Elements

    SciTech Connect

    Gottwald, T.; Mattolat, C.; Raeder, S.; Wendt, K.; Lassen, J.; Liu, Y.

    2009-03-17

    Spectroscopic investigations of the rare earth elements Tb, Dy and Ho have been carried out using laser resonance ionization mass spectroscopy. A variety of new intermediate energy levels and autoionizing states were observed in these elements. Efficient and selective excitation and ionization schemes for the elements have been developed for Ti:Sapphire lasers using the spectroscopic data. Resonant ionization schemes for Np were also been studied as the preparation work for related investigations on actinide elements and for the spectroscopy on the heaviest elements, where spectroscopic data so far are scarce or not existing at all.

  8. EDITORIAL Neuroglia as a Central Element of Neurological Diseases: An Underappreciated Target for Therapeutic Intervention

    PubMed Central

    Peng, Liang; Parpura, Vladimir; Verkhratsky, Alexei

    2014-01-01

    Neuroglia of the central nervous system (CNS), represented by cells of neural (astrocytes, oligodendrocytes and NG2 glial cells) and myeloid (microglia) origins are fundamental for homeostasis of the nervous tissue. Astrocytes are critical for the development of the CNS, they are indispensable for synaptogenesis, and they define structural organisation of the nervous tissue, as well as the generation and maintenance of CNS-blood and cerebrospinal fluid-blood barriers. Astroglial cells control homeostasis of ions and neurotransmitters and provide neurones with metabolic support. Oligodendrocytes, through the process of myelination, as well as by homoeostatic support of axons provide for interneuronal connectivity. The NG2 cells receive direct synaptic inputs, and might be important elements of adult remyelination. Microglial cells, which originate from foetal macrophages invading the brain early in embryogenesis, shape the synaptic connections through removing of redundant synapses and phagocyting apoptotic neurones. Neuroglia also form the defensive system of the CNS through complex and context-specific programmes of activation, known as reactive gliosis. Many neurological diseases are associated with neurogliopathologies represented by asthenic and atrophic changes in glial cells that, through the loss or diminution of their homeostatic and defensive functions, assist evolution of pathology. Conceptually, neurological and psychiatric disorders can be regarded as failures of neuroglial homeostatic/ defensive responses, and, hence, glia represent a (much underappreciated) target for therapeutic intervention. PMID:25342938

  9. Molecular basis of PRC1 targeting to Polycomb response elements by PhoRC

    PubMed Central

    Frey, Felice; Sheahan, Thomas; Finkl, Katja; Stoehr, Gabriele; Mann, Matthias; Benda, Christian; Müller, Jürg

    2016-01-01

    Polycomb group (PcG) protein complexes repress transcription by modifying target gene chromatin. In Drosophila, this repression requires association of PcG protein complexes with cis-regulatory Polycomb response elements (PREs), but the interactions permitting formation of these assemblies are poorly understood. We show that the Sfmbt subunit of the DNA-binding Pho-repressive complex (PhoRC) and the Scm subunit of the canonical Polycomb-repressive complex 1 (PRC1) directly bind each other through their SAM domains. The 1.9 Å crystal structure of the Scm-SAM:Sfmbt-SAM complex reveals the recognition mechanism and shows that Sfmbt-SAM lacks the polymerization capacity of the SAM domains of Scm and its PRC1 partner subunit, Ph. Functional analyses in Drosophila demonstrate that Sfmbt-SAM and Scm-SAM are essential for repression and that PhoRC DNA binding is critical to initiate PRC1 association with PREs. Together, this suggests that PRE-tethered Sfmbt-SAM nucleates PRC1 recruitment and that Scm-SAM/Ph-SAM-mediated polymerization then results in the formation of PRC1-compacted chromatin. PMID:27151979

  10. Expression of the Arabidopsis transposable element Tag1 is targeted to developing gametophytes.

    PubMed Central

    Galli, Mary; Theriault, Angie; Liu, Dong; Crawford, Nigel M

    2003-01-01

    The Arabidopsis transposon Tag1 undergoes late excision during vegetative and germinal development in plants containing 35S-Tag1-GUS constructs. To determine if transcriptional regulation can account for the developmental control of Tag1 excision, the transcriptional activity of Tag1 promoter-GUS fusion constructs of various lengths was examined in transgenic plants. All constructs showed expression in the reproductive organs of developing flowers but no expression in leaves. Expression was restricted to developing gametophytes in both male and female lineages. Quantitative RT-PCR analysis confirmed that Tag1 expression predominates in the reproductive organs of flower buds. These results are consistent with late germinal excision of Tag1, but they cannot explain the vegetative excision activity of Tag1 observed with 35S-Tag1-GUS constructs. To resolve this issue, Tag1 excision was reexamined using elements with no adjacent 35S promoter sequences. Tag1 excision in this context is restricted to germinal events with no detectable vegetative excision. If a 35S enhancer sequence is placed next to Tag1, vegetative excision is restored. These results indicate that the intrinsic activity of Tag1 is restricted to germinal excision due to targeted expression of the Tag1 transposase to developing gametophytes and that this activity is altered by the presence of adjacent enhancers or promoters. PMID:14704189

  11. Activity of a Py-Im polyamide targeted to the estrogen response element.

    PubMed

    Nickols, Nicholas G; Szablowski, Jerzy O; Hargrove, Amanda E; Li, Benjamin C; Raskatov, Jevgenij A; Dervan, Peter B

    2013-05-01

    Pyrrole-imidazole (Py-Im) polyamides are a class of programmable DNA minor groove binders capable of modulating the activity of DNA-binding proteins and affecting changes in gene expression. Estrogen receptor alpha (ERα) is a ligand-activated hormone receptor that binds as a homodimer to estrogen response elements (ERE) and is a driving oncogene in a majority of breast cancers. We tested a selection of structurally similar Py-Im polyamides with differing DNA sequence specificity for activity against 17β-estadiol (E2)-induced transcription and cytotoxicity in ERα positive, E2-stimulated T47DKBluc cells, which express luciferase under ERα control. The most active polyamide targeted the sequence 5'-WGGWCW-3' (W = A or T), which is the canonical ERE half site. Whole transcriptome analysis using RNA-Seq revealed that treatment of E2-stimulated breast cancer cells with this polyamide reduced the effects of E2 on the majority of those most strongly affected by E2 but had much less effect on the majority of E2-induced transcripts. In vivo, this polyamide circulated at detectable levels following subcutaneous injection and reduced levels of ER-driven luciferase expression in xenografted tumors in mice after subcutaneous compound administration without significant host toxicity.

  12. Qualification of high heat flux components: application to target elements of W7-X divertor

    NASA Astrophysics Data System (ADS)

    Missirlian, M.; Durocher, A.; Grosman, A.; Schlosser, J.; Boscary, J.; Escourbiac, F.; Cismondi, F.

    2007-03-01

    The development of actively cooled plasma-facing components (PFC) represents one of fusion's most challenging engineering efforts. In this frame, a high-quality bonding between the refractory armour and the heat sink is essential to ensure the heat removal capability and the thermal performances of PFC. Experience gained during manufacturing of Tore Supra actively cooled PFC led to the establishment of a qualification methodology and provided a large experience of acceptance criteria using an active infrared thermography (système d'acquisition de traitement infra-rouge, SATIR). This paper presents the application of this qualification process to the W7-X pre-series components, with the objective of assessing and defining workable acceptance criteria that enable reliable predictions of performance at the nominal heat flux requirements in W7-X. Finally, to check the reliability of the non-destructive examination (NDE) method by transient infrared thermography, the newly defined acceptance criteria were applied to W7-X pre-series target elements (batch #3). The SATIR results, benchmarked with HHF tests performed on the GLADIS ion beam facility were discussed to assess the ability to detect critical defects at the interface between tiles and heat sink.

  13. Real-world emission factors for antimony and other brake wear related trace elements: size-segregated values for light and heavy duty vehicles.

    PubMed

    Bukowiecki, Nicolas; Lienemann, Peter; Hill, Matthias; Figi, Renato; Richard, Agnes; Furger, Markus; Rickers, Karen; Falkenberg, Gerald; Zhao, Yongjing; Cliff, Steven S; Prevot, Andre S H; Baltensperger, Urs; Buchmann, Brigitte; Gehrig, Robert

    2009-11-01

    Hourly trace element measurements were performed in an urban street canyon and next to an interurban freeway in Switzerland during more than one month each, deploying a rotating drum impactor (RDI) and subsequent sample analysis by synchrotron radiation X-ray fluorescence spectrometry (SR-XRF). Antimony and other brake wear associated elements were detected in three particle size ranges (2.5-10, 1-2.5, and 0.1-1 microm). The hourly measurements revealed that the effect of resuspended road dust has to be taken into account for the calculation of vehicle emission factors. Individual values for light and heavy duty vehicles were obtained for stop-and-go traffic in the urban street canyon. Mass based brake wear emissions were predominantly found in the coarse particle fraction. For antimony, determined emission factors were 11 +/- 7 and 86 +/- 42 microg km(-1) vehicle(-1) for light and heavy duty vehicles, respectively. Antimony emissions along the interurban freeway with free-flowing traffic were significantly lower. Relative patterns for brake wear related elements were very similar for both considered locations. Beside vehicle type specific brake wear emissions, road dust resuspension was found to be a dominant contributor of antimony in the street canyon.

  14. Heavy metal and trace element distributions in groundwater in natural slopes and highly urbanized spaces in Mid-Levels area, Hong Kong.

    PubMed

    Leung, Chi-Man; Jiao, Jiu Jimmy

    2006-02-01

    The lower slope of the Mid-Levels area, Hong Kong, is one the most heavily urbanized coastal areas in the world. A comprehensive groundwater heavy metal and trace element study was conducted in the Mid-Levels area aiming to investigate the impacts of urbanization on the aqueous distributions of these chemicals. Groundwater samples were collected in the upper natural slopes and the lower highly urbanized spaces in the area in different seasons, and analyzed for heavy metal and trace element contents. Compared to the results from natural slopes, groundwater samples in the developed spaces did not exhibit significant elevated levels in Zn, Cr, Cu, Cd, Pb and Fe, which are commonly found in stormwater. On the other hand, the samples were found to have elevated contents in Mn, V, Co and Mo, minor stormwater-related heavy metals, suggesting that stormwater drains may be leaking to some extent. However, the results suggested that the vadose zone could remove many of the heavy metals, protecting groundwater from being contaminated seriously. Statistical analysis suggested that a certain amount of Mn and Co was likely to be re-mobilized from natural soils due to the changes in local redox conditions, while Mn, V, Co and Mo may also be derived from steel corrosion as a result of prolonged submergence. Besides, the average B concentration in the developed spaces was about eight times higher than that in the natural slopes, indicating the presence of sewage. The mean Se concentration in the developed spaces was about 100 times higher than that in the natural slopes. About 40% of samples in the developed spaces contained Se level higher than the drinking water guideline value proposed by the World Health Organization. Se was found to be positively correlated with B and SO4(2-) (R = 0.534 and 0.631, respectively), suggesting that Se may also be related to leakage from sewage pipes. Part of the Sr may come from leakage of flushing water and/or sewage as Sr was strongly correlated

  15. Origin assignment of unidentified corpses by use of stable isotope ratios of light (bio-) and heavy (geo-) elements--a case report.

    PubMed

    Rauch, Elisabeth; Rummel, Susanne; Lehn, Christine; Büttner, Andreas

    2007-05-24

    An unknown male body was found near an expressway in Germany. As different criminalistic and forensic methods (e.g. tooth status, fingerprint or DNA-analysis) could not help to identify the person, multielement stable isotope investigations were applied. The combined analysis of stable isotope ratios of light (H, C, N) and heavy elements (Pb, Sr) on the man's body tissues supported to assign him to Romania. The case report demonstrates an application of multielement-isotope analysis in the forensic fields and its potential.

  16. High-energy accelerator for beams of heavy ions

    DOEpatents

    Martin, Ronald L.; Arnold, Richard C.

    1978-01-01

    An apparatus for accelerating heavy ions to high energies and directing the accelerated ions at a target comprises a source of singly ionized heavy ions of an element or compound of greater than 100 atomic mass units, means for accelerating the heavy ions, a storage ring for accumulating the accelerated heavy ions and switching means for switching the heavy ions from the storage ring to strike a target substantially simultaneously from a plurality of directions. In a particular embodiment the heavy ion that is accelerated is singly ionized hydrogen iodide. After acceleration, if the beam is of molecular ions, the ions are dissociated to leave an accelerated singly ionized atomic ion in a beam. Extraction of the beam may be accomplished by stripping all the electrons from the atomic ion to switch the beam from the storage ring by bending it in magnetic field of the storage ring.

  17. Growth Suppression of Lung Cancer Cells by Targeting Cyclic AMP Response Element-Binding Protein

    PubMed Central

    Aggarwal, Sita; Kim, Seung-Wook; Ryu, Seung-Hee; Chung, Wen-Cheng; Koo, Ja Seok

    2010-01-01

    Genes regulated by cyclic AMP response element-binding protein (CREB) have been reported to suppress apoptosis, induce cell proliferation, and mediate inflammation and tumor metastasis. However, it is not clear whether CREB is critically involved in the carcinogenesis of lung cancer. We found that non-small cell lung cancer (NSCLC) cell lines exhibited elevated constitutive activity in CREB; in its immediate upstream kinases, ribosomal s6 kinase and extracellular signal kinase; and in the CREB-regulated cell survival proteins, Bcl-2 and Bcl-xL. We hypothesized that constitutively active CREB is important to lung cancer cell growth and survival and therefore could be a potential therapeutic target for NSCLC. Ectopic expression of dominant-repressor CREB and transfection with small interfering RNA against CREB suppressed the growth and survival of NSCLC cells and induced apoptotic cell death. Furthermore, treating H1734 NSCLC cells with an inhibitor of the CREB signaling pathway, Ro-31-8220, inhibited CREB activation by blocking the activity of extracellular signal kinase and ribosomal s6 kinase, arrested the cell cycle at the G2/M phase, and subsequently induced apoptosis with the suppression of Bcl-2 and Bcl-xL expression. Ro-31-8220 suppressed both the anchorage-dependent and the independent growth of NSCLC cells, but its cytotoxic effect was much less prominent in normal bronchial epithelial cells. Our results indicate that active CREB plays an important role in NSCLC cell growth and survival. Thus, agents that suppress CREB activation could have potential therapeutic value for NSCLC treatment. PMID:18281471

  18. Optimization of laser induced breakdown spectroscopy system by neurogenetic method for multi-elemental analysis of heavy metals in soil

    NASA Astrophysics Data System (ADS)

    Liu, Lituo; Liu, Jianguo; Zhao, Nanjing; Wang, Yin; Shi, Huan; Wang, Chunlong; Zhang, Yujun; Liu, Wenqing

    2011-11-01

    Laser indued breakdown spectroscopy(LIBS) system was used for analysis of heavy metals (Cr, Pb, Cu, Ni, Cd, Zn) in soil. And neuro-genetic method was applied to optimize the system parameters in order to maximize the signal-background ratio of all heavy metals simultaneously. LIBS system equipped with an Andor Echelle spectrometer, coupled to an ICCD detector. A Q-switched Nd:YAG laser was used to induced plazma. Delay time, integration time, scan times of laser pluse, frequency of laser were optimized. The optimized parameters were obtained: 1μs delay time, 4.5μs integration time, 48 scan times, and 11Hz frequency of laser.

  19. Effect of silver nanoparticles on concentration of silver heavy element and growth indexes in cucumber ( Cucumis sativus L . negeen)

    NASA Astrophysics Data System (ADS)

    Shams, Gholamabbas; Ranjbar, Morteza; Amiri, Aliasghar

    2013-05-01

    The tremendous progress on nanoparticle research area has been made significant effects on the economy, society, and the environment. Silver nanoparticle is one of the most important particles in these categories. Silver nanoparticles can be converted to the heavy silver metal in water by oxidation. Moreover, in the high amounts of silver concentration, they will be accumulated in different parts of the plant. However, by changing the morphology of the plant, the production will be harmful for human consumptions. In this study, nano-powders with average 50 nm silver particles are mixed with deionized distilled water in a completely randomized design. Seven treatments with various concentrations of suspension silver nanoparticles were prepared and repeated in four different parts of the plant in a regular program of spraying. Samples were analyzed to study the growth indexes and concentration of silver in different parts of the plant. It was observed that with increasing concentration of silver nanoparticles on cucumber, the growth indexes (except pH fruit), and the concentration of silver heavy metal are increased significantly. The incremental concentration had the linear relationship with correlation coefficient 0.95 and an average of 0.617 PPM by increasing of each unit in one thousand concentration of nanosilver. Although, by increasing concentration of silver nanoparticles as spraying form, the plant morphological characteristics were improved, the concentration of silver heavy metal in various plant organs was increased. These results open a new pathway to consider the effect of nanoparticles on plant's productions for human consumptions.

  20. New X-ray microprobe system for trace heavy element analysis using ultraprecise X-ray mirror optics of long working distance

    NASA Astrophysics Data System (ADS)

    Terada, Yasuko; Yumoto, Hirokatsu; Takeuchi, Akihisa; Suzuki, Yoshio; Yamauchi, Kazuto; Uruga, Tomoya

    2010-05-01

    A new X-ray microprobe system for trace heavy element analysis using ultraprecise X-ray mirror optics of 300 mm long working distance has been developed at beamline 37XU of SPring-8. A focusing test has been performed in the X-ray energy range 20-37.7 keV. A focused beam size of 1.3 μm ( V)×1.5 μm ( H) has been achieved at an X-ray energy of 30 keV, and a total photon flux of the focused beam was about 2.7×10 10 photons/s. Micro-X-ray fluorescence (μ-XRF) analysis of eggplant roots has been carried out using the developed microprobe. It is clearly observed in the XRF images that cadmium is highly accumulated in the endodermis, exodermis and epidermis of roots. This study demonstrates the potential of scanning microscopy for heavy elements analysis in the high-energy X-ray region.

  1. [Research on the content of trace elements and heavy metals in the three kinds of Zhejiang specific medicinal materials before and after processing].

    PubMed

    Yuan, Ke; Wang, Lin; Sun, Su-Qin; Yin, Ming-Wen

    2010-05-01

    By establishing the ICP-MS determining method, we determined the contents of Mn, Fe, Cu, Zn, Cr, As, Cd and Pb in the three kinds of Zhejiang specific medicinal materials before and after processing them. The recovery ratio with standard addition of the method is between 95.2% and 106.3, and the relative standard deviation between 0.69% and 2.34%. The results of the experiment show that the contents of useful metals Mn, Fe, Cu and Zn are fairly high both before and after processing, while the contents of harmful heavy metals Cd, Cr, Pb and As are all lower than the limited quantity in the standard of Chinese Pharmacopoeia. After processing, there seems to be some content changes in the trace elements and heavy metals. Different content changes depend on different processing methods. After processing, except the notable decrease in Pb, the contents of Cu, As and Cd are almost constant, while the contents of other elements are nearly all increased. The result seems to be related with the methods of processing. This experimental result provides us with new scientific foundation for the further research on the relationship between different processing methods and different efficacy of the three specific Zhejiang medicinal materials.

  2. Poly(dA-dT) promoter elements increase the equilibrium accessibility of nucleosomal DNA target sites.

    PubMed

    Anderson, J D; Widom, J

    2001-06-01

    Polypurine tracts are important elements of eukaryotic promoters. They are believed to somehow destabilize chromatin, but the mechanism of their action is not known. We show that incorporating an A(16) element at an end of the nucleosomal DNA and further inward destabilizes histone-DNA interactions by 0.1 +/- 0.03 and 0.35 +/- 0.04 kcal mol(-1), respectively, and is accompanied by 1.5- +/- 0.1-fold and 1.7- +/- 0.1-fold increases in position-averaged equilibrium accessibility of nucleosomal DNA target sites. These effects are comparable in magnitude to effects of A(16) elements that correlate with transcription in vivo, suggesting that our system may capture most of their physiological role. These results point to two distinct but interrelated models for the mechanism of action of polypurine tract promoter elements in vivo. Given a nucleosome positioned over a promoter region, the presence of a polypurine tract in that nucleosome's DNA decreases the stability of the DNA wrapping, increasing the equilibrium accessibility of other DNA target sites buried inside that nucleosome. Alternatively (if nucleosomes are freely mobile), the presence of a polypurine tract provides a free energy bias for the nucleosome to move to alternative locations, thereby changing the equilibrium accessibilities of other nearby DNA target sites.

  3. High conservation of a 5' element required for RNA editing of a C target in chloroplast psbE transcripts.

    PubMed

    Hayes, Michael L; Hanson, Maureen R

    2008-09-01

    C-to-U editing modifies 30-40 distinct nucleotides within higher-plant chloroplast transcripts. Many C targets are located at the same position in homologous genes from different plants; these either could have emerged independently or could share a common origin. The 5' sequence GCCGUU, required for editing of C214 in tobacco psbE in vitro, is one of the few identified editing cis-elements. We investigated psbE sequences from many plant species to determine in what lineage(s) editing of psbE C214 emerged and whether the cis-element identified in tobacco is conserved in plants with a C214. The GCCGUU sequence is present at a high frequency in plants that carry a C214 in psbE. However, Sciadopitys verticillata (Pinophyta) edits C214 despite the presence of nucleotide differences compared to the conserved cis-element. The C214 site in psbE genes is represented in members of four branches of spermatophytes but not in gnetophytes, resulting in the parsimonious prediction that editing of psbE C214 was present in the ancestor of spermatophytes. Extracts from chloroplasts from a species that has a difference in the motif and lacks the C target are incapable of editing tobacco psbE C214 substrates, implying that the critical trans-acting protein factors were not retained without a C target. Because noncoding sequences are less constrained than coding regions, we analyzed sequences 5' to two C editing targets located within coding regions to search for possible editing-related conserved elements. Putative editing cis-elements were uncovered in the 5' UTRs near editing sites psbL C2 and ndhD C2.

  4. Rotifer rDNA-specific R9 retrotransposable elements generate an exceptionally long target site duplication upon insertion.

    PubMed

    Gladyshev, Eugene A; Arkhipova, Irina R

    2009-12-15

    Ribosomal DNA genes in many eukaryotes contain insertions of non-LTR retrotransposable elements belonging to the R2 clade. These elements persist in the host genomes by inserting site-specifically into multicopy target sites, thereby avoiding random disruption of single-copy host genes. Here we describe R9 retrotransposons from the R2 clade in the 28S RNA genes of bdelloid rotifers, small freshwater invertebrate animals best known for their long-term asexuality and for their ability to survive repeated cycles of desiccation and rehydration. While the structural organization of R9 elements is highly similar to that of other members of the R2 clade, they are characterized by two distinct features: site-specific insertion into a previously unreported target sequence within the 28S gene, and an unusually long target site duplication of 126 bp. We discuss the implications of these findings in the context of bdelloid genome organization and the mechanisms of target-primed reverse transcription.

  5. Heavy Chain-Only IgG2b Llama Antibody Effects Near-Pan HIV-1 Neutralization by Recognizing a CD4-Induced Epitope That Includes Elements of Coreceptor- and CD4-Binding Sites

    PubMed Central

    Luongo, Timothy S.; Georgiev, Ivelin S.; Matz, Julie; Schmidt, Stephen D.; Louder, Mark K.; Kessler, Pascal; Yang, Yongping; McKee, Krisha; O'Dell, Sijy; Chen, Lei; Baty, Daniel; Chames, Patrick; Martin, Loïc; Mascola, John R.

    2013-01-01

    The conserved HIV-1 site of coreceptor binding is protected from antibody-directed neutralization by conformational and steric restrictions. While inaccessible to most human antibodies, the coreceptor site has been shown to be accessed by antibody fragments. In this study, we used X-ray crystallography, surface plasmon resonance, and pseudovirus neutralization to characterize the gp120-envelope glycoprotein recognition and HIV-1 neutralization of a heavy chain-only llama antibody, named JM4. We describe full-length IgG2b and IgG3 versions of JM4 that target the coreceptor-binding site and potently neutralize over 95% of circulating HIV-1 isolates. Contrary to established trends that show improved access to the coreceptor-binding region by smaller antibody fragments, the single-domain (VHH) version of JM4 neutralized less well than the full-length IgG2b version of JM4. The crystal structure at 2.1-Å resolution of VHH JM4 bound to HIV-1 YU2 gp120 stabilized in the CD4-bound state by the CD4-mimetic miniprotein, M48U1, revealed a JM4 epitope that combined regions of coreceptor recognition (including the gp120 bridging sheet, V3 loop, and β19 strand) with gp120 structural elements involved in recognition of CD4 such as the CD4-binding loop. The structure of JM4 with gp120 thus defines a novel CD4-induced site of vulnerability involving elements of both coreceptor- and CD4-binding sites. The potently neutralizing JM4 IgG2b antibody that targets this newly defined site of vulnerability adds to the expanding repertoire of broadly neutralizing antibodies that effectively neutralize HIV-1 and thereby potentially provides a new template for vaccine development and target for HIV-1 therapy. PMID:23843638

  6. Heavy chain-only IgG2b llama antibody effects near-pan HIV-1 neutralization by recognizing a CD4-induced epitope that includes elements of coreceptor- and CD4-binding sites.

    PubMed

    Acharya, Priyamvada; Luongo, Timothy S; Georgiev, Ivelin S; Matz, Julie; Schmidt, Stephen D; Louder, Mark K; Kessler, Pascal; Yang, Yongping; McKee, Krisha; O'Dell, Sijy; Chen, Lei; Baty, Daniel; Chames, Patrick; Martin, Loïc; Mascola, John R; Kwong, Peter D

    2013-09-01

    The conserved HIV-1 site of coreceptor binding is protected from antibody-directed neutralization by conformational and steric restrictions. While inaccessible to most human antibodies, the coreceptor site has been shown to be accessed by antibody fragments. In this study, we used X-ray crystallography, surface plasmon resonance, and pseudovirus neutralization to characterize the gp120-envelope glycoprotein recognition and HIV-1 neutralization of a heavy chain-only llama antibody, named JM4. We describe full-length IgG2b and IgG3 versions of JM4 that target the coreceptor-binding site and potently neutralize over 95% of circulating HIV-1 isolates. Contrary to established trends that show improved access to the coreceptor-binding region by smaller antibody fragments, the single-domain (VHH) version of JM4 neutralized less well than the full-length IgG2b version of JM4. The crystal structure at 2.1-Å resolution of VHH JM4 bound to HIV-1 YU2 gp120 stabilized in the CD4-bound state by the CD4-mimetic miniprotein, M48U1, revealed a JM4 epitope that combined regions of coreceptor recognition (including the gp120 bridging sheet, V3 loop, and β19 strand) with gp120 structural elements involved in recognition of CD4 such as the CD4-binding loop. The structure of JM4 with gp120 thus defines a novel CD4-induced site of vulnerability involving elements of both coreceptor- and CD4-binding sites. The potently neutralizing JM4 IgG2b antibody that targets this newly defined site of vulnerability adds to the expanding repertoire of broadly neutralizing antibodies that effectively neutralize HIV-1 and thereby potentially provides a new template for vaccine development and target for HIV-1 therapy.

  7. HELAC-Onia 2.0: An upgraded matrix-element and event generator for heavy quarkonium physics

    NASA Astrophysics Data System (ADS)

    Shao, Hua-Sheng

    2016-01-01

    We present an upgraded version (denoted as version 2.0) of the program HELAC-ONIA for the automated computation of heavy-quarkonium helicity amplitudes within non-relativistic QCD framework. The new code has been designed to include many new and useful features for practical phenomenological simulations. It is designed for job submissions under cluster environment for parallel computations via PYTHON scripts. We have interfaced HELAC-ONIA to the parton shower Monte Carlo programs PYTHIA 8 and QEDPS to take into account the parton-shower effects. Moreover, the decay module guarantees that the program can perform the spin-entangled (cascade-)decay of heavy quarkonium after its generation. We have also implemented a reweighting method to automatically estimate the uncertainties from renormalization and/or factorization scales as well as parton-distribution functions to weighted or unweighted events. A further update is the possibility to generate one-dimensional or two-dimensional plots encoded in the analysis files on the fly. Some dedicated examples are given at the end of the writeup.

  8. Spin-Orbit Effects in Closed-Shell Heavy and Superheavy Element Monohydrides and Monofluorides with Coupled-Cluster Theory.

    PubMed

    Gao, Dong-Dong; Cao, Zhanli; Wang, Fan

    2016-03-03

    Bond lengths and force constants of a set of closed-shell sixth-row and superheavy element monohydrides and monofluorides are calculated in this work. Kramers restricted coupled-cluster approaches (KR-CC) with spin-orbit coupling (SOC) included at the self-consistent field (SCF) level as well as CC approaches with SOC included in post-SCF treatment (SOC-CC) are employed in calculations. Recently published relativistic effective core potentials are employed, and highly accurate results for superheavy element molecules are achieved with KR-CCSD(T). SOC effects on bond lengths and force constants of these molecules are investigated. Effects of electron correlation are shown to be affected by SOC to a large extent for some superheavy element molecules. Bond lengths and force constants with SOC-CC agree very well with those of KR-CC for most of the sixth-row element molecules. As for superheavy element molecules, SOC-CCSD is able to afford results that are in good agreement with those of KR-CCSD except for 111F, while the error of SOC-CCSD(T) is more pronounced. Large error would be encountered with SOC-CC approaches for molecules when both SOC and electron correlation effects are sizable.

  9. Heavy-ion double charge exchange reactions: A tool toward 0 νββ nuclear matrix elements

    NASA Astrophysics Data System (ADS)

    Cappuzzello, F.; Cavallaro, M.; Agodi, C.; Bondì, M.; Carbone, D.; Cunsolo, A.; Foti, A.

    2015-11-01

    The knowledge of the nuclear matrix elements for the neutrinoless double beta decay is fundamental for neutrino physics. In this paper, an innovative technique to extract information on the nuclear matrix elements by measuring the cross section of a double charge exchange nuclear reaction is proposed. The basic point is that the initial- and final-state wave functions in the two processes are the same and the transition operators are similar. The double charge exchange cross sections can be factorized in a nuclear structure term containing the matrix elements and a nuclear reaction factor. First pioneering experimental results for the 40Ca(18O,18Ne)40Ar reaction at 270 MeV incident energy show that such cross section factorization reasonably holds for the crucial 0+ → 0+ transition to 40Args, at least at very forward angles.

  10. Determining the DNA sequence elements required for binding integration host factor to two different target sites.

    PubMed Central

    Hales, L M; Gumport, R I; Gardner, J F

    1994-01-01

    Binding sites for the Escherichia coli protein integration host factor (IHF) include a set of conserved bases that can be summarized by the consensus sequence WATCAANNNNTTR (W is dA or dT, R is dA or dG, and N is any nucleotide). However, additional 5'-proximal bases, whose common feature is a high dA+dT content, are also thought to be required for binding at some sites. We examine the relative contribution of these two sequence elements to IHF binding to the H' and H1 sites in attP of bacteriophage lambda by using the bacteriophage P22-based challenge-phage system. IHF was unable to act as a repressor in the challenge-phage assay at H' sites containing the core consensus element but lacking the dA+dT-rich element. This indicates that both elements are required for IHF to bind to the H' site. In contrast, the core consensus determinant alone is sufficient for IHF binding to the H1 site, which lacks an upstream dA+dT-rich region. Fifty mutants that decreased or eliminated IHF binding to the H1 site were isolated. Sequence analysis showed changes in the bases in the core consensus element only, further indicating that this determinant is sufficient for IHF binding to the H1 site. We found that placement of a dA+dT-rich element upstream of the H1 core consensus element significantly increased the affinity, suggesting that the presence of a dA+dT-rich element enhances IHF binding. PMID:8188600

  11. Influence of season and diet on liver and kidney content of essential elements and heavy metals in Svalbard reindeer.

    PubMed

    Borch-Iohnsen, B; Nilssen, K J; Norheim, G

    1996-03-01

    Samples of liver (n = 78) and kidney (n = 60) from Svalbard reindeer (Rangifer tarandus platyrhynchus Vrolik) collected at four different seasons in Svalbard were analysed for their content of Cd, Pb, Cu, Zn, Mn, and Se. The study shows that when animals are exposed to large seasonal variations in both the quality and quantity of food, it is crucial to relate element concentrations to the physiological condition of the animal, e.g., to look at seasonal fluctuations in the total element content of the different organs.

  12. An in silico strategy identified the target gene candidates regulated by dehydration responsive element binding proteins (DREBs) in Arabidopsis genome.

    PubMed

    Wang, Shichen; Yang, Shuo; Yin, Yuejia; Guo, Xiaosen; Wang, Shan; Hao, Dongyun

    2009-01-01

    Identification of downstream target genes of stress-relating transcription factors (TFs) is desirable in understanding cellular responses to various environmental stimuli. However, this has long been a difficult work for both experimental and computational practices. In this research, we presented a novel computational strategy which combined the analysis of the transcription factor binding site (TFBS) contexts and machine learning approach. Using this strategy, we conducted a genome-wide investigation into novel direct target genes of dehydration responsive element binding proteins (DREBs), the members of AP2-EREBPs transcription factor super family which is reported to be responsive to various abiotic stresses in Arabidopsis. The genome-wide searching yielded in total 474 target gene candidates. With reference to the microarray data for abiotic stresses-inducible gene expression profile, 268 target gene candidates out of the total 474 genes predicted, were induced during the 24-h exposure to abiotic stresses. This takes about 57% of total predicted targets. Furthermore, GO annotations revealed that these target genes are likely involved in protein amino acid phosphorylation, protein binding and Endomembrane sorting system. The results suggested that the predicted target gene candidates were adequate to meet the essential biological principle of stress-resistance in plants.

  13. Superheavy Elements

    NASA Astrophysics Data System (ADS)

    Hofmann, S.

    The nuclear shell model predicts that the next doubly magic shell closure beyond 208Pb is at a proton number Z=114, 120, or 126 and at a neutron number N=172 or 184. The outstanding aim of experimental investigations is the exploration of this region of spherical `SuperHeavy Elements' (SHEs). Experimental methods have been developed which allowed for the identification of new elements at production rates of one atom per month. Using cold fusion reactions which are based on lead and bismuth targets, relatively neutron-deficient isotopes of the elements from 107 to 113 were synthesized at GSI in Darmstadt, Germany, and/or at RIKEN in Wako, Japan. In hot fusion reactions of 48Ca projectiles with actinide targets more neutron-rich isotopes of the elements from 112 to 116 and even 118 were produced at the Flerov Laboratory of Nuclear Reactions (FLNR) at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. Recently, part of these data which represent the first identification of nuclei located on the predicted island of SHEs were confirmed in two independent experiments. The decay data reveal that for the heaviest elements, the dominant decay mode is α emission rather than fission. Decay properties as well as reaction cross-sections are compared with results of theoretical studies. Finally, plans are presented for the further development of the experimental set-up and the application of new techniques. At a higher sensitivity, the detailed exploration of the region of spherical SHEs will be in the center of interest of future experimental work. New data will certainly challenge theoretical studies on the mechanism of the synthesis, on the nuclear decay properties, and on the chemical behavior of these heaviest atoms at the limit of stability.

  14. Levels of rare earth elements, heavy metals and uranium in a population living in Baiyun Obo, Inner Mongolia, China: a pilot study.

    PubMed

    Hao, Zhe; Li, Yonghua; Li, Hairong; Wei, Binggan; Liao, Xiaoyong; Liang, Tao; Yu, Jiangping

    2015-06-01

    The Baiyun Obo deposit is the world's largest rare earth elements (REE) deposit. We aimed to investigate levels of REE, heavy metals (HMs) and uranium (U) based on morning urine samples in a population in Baiyun Obo and to assess the possible influence of rare earth mining processes on human exposure. In the mining area, elevated levels were found for the sum of the concentrations of light REE (LREE) and heavy REE (HREE) with mean values at 3.453 and 1.151 μg g(-1) creatinine, which were significantly higher than those in the control area. Concentrations of HMs and U in the population increased concomitantly with increasing REE levels. The results revealed that besides REE, HMs and U were produced with REE exploitation. Gender, age, educational level, alcohol and smoking habit were major factors contributing to inter-individual variation. Males were more exposed to these metals than females. Concentrations in people in the senior age group and those with only primary education were low. Drinking and smoking were associated with the levels of LREE, Cr, Cu, Cd and Pb in morning urine. Hence this study provides basic and useful information when addressing public and environmental health challenges in the areas where REE are mined and processed.

  15. Vented target elements for use in an isotope-production reactor. [LMFBR

    DOEpatents

    Cawley, W.E.; Omberg, R.P.

    1982-08-19

    A method is described for producing tritium gas in a fast breeder reactor cooled with liquid metal. Lithium target material is placed in pins equipped with vents, and tritium gas is recovered from the coolant.

  16. KEPLER-15b: A HOT JUPITER ENRICHED IN HEAVY ELEMENTS AND THE FIRST KEPLER MISSION PLANET CONFIRMED WITH THE HOBBY-EBERLY TELESCOPE

    SciTech Connect

    Endl, Michael; MacQueen, Phillip J.; Cochran, William D.; Brugamyer, Erik J.; Buchhave, Lars A.; Rowe, Jason; Lucas, Phillip; Isaacson, Howard; Bryson, Steve; Howell, Steve B.; Borucki, William J.; Caldwell, Douglas; Christiansen, Jessie L.; Haas, Michael R.; Fortney, Jonathan J.; Hansen, Terese; Ciardi, David R.; Everett, Mark; Ford, Eric B.; and others

    2011-11-01

    We report the discovery of Kepler-15b (KOI-128), a new transiting exoplanet detected by NASA's Kepler mission. The transit signal with a period of 4.94 days was detected in the quarter 1 (Q1) Kepler photometry. For the first time, we have used the High Resolution Spectrograph (HRS) at the Hobby-Eberly Telescope (HET) to determine the mass of a Kepler planet via precise radial velocity (RV) measurements. The 24 HET/HRS RVs and 6 additional measurements from the Fibre-fed Echelle Spectrograph spectrograph at the Nordic Optical Telescope reveal a Doppler signal with the same period and phase as the transit ephemeris. We used one HET/HRS spectrum of Kepler-15 taken without the iodine cell to determine accurate stellar parameters. The host star is a metal-rich ([Fe/H] = 0.36 {+-} 0.07) G-type main-sequence star with T{sub eff} = 5515 {+-} 124 K. The semi-amplitude K of the RV orbit is 78.7{sup +8.5}{sub -9.5} m s{sup -1}, which yields a planet mass of 0.66 {+-} 0.1 M{sub Jup}. The planet has a radius of 0.96 {+-} 0.06 R{sub Jup} and a mean bulk density of 0.9 {+-} 0.2 g cm{sup -3}. The radius of Kepler-15b is smaller than the majority of transiting planets with similar mass and irradiation level. This suggests that the planet is more enriched in heavy elements than most other transiting giant planets. For Kepler-15b we estimate a heavy element mass of 30-40 M{sub Circled-Plus }.

  17. Kepler-15b: A Hot Jupiter Enriched in Heavy Elements and the First Kepler Mission Planet Confirmed with the Hobby-Eberly Telescope

    NASA Astrophysics Data System (ADS)

    Endl, Michael; MacQueen, Phillip J.; Cochran, William D.; Brugamyer, Erik J.; Buchhave, Lars A.; Rowe, Jason; Lucas, Phillip; Isaacson, Howard; Bryson, Steve; Howell, Steve B.; Fortney, Jonathan J.; Hansen, Terese; Borucki, William J.; Caldwell, Douglas; Christiansen, Jessie L.; Ciardi, David R.; Demory, Brice-Olivier; Everett, Mark; Ford, Eric B.; Haas, Michael R.; Holman, Matthew J.; Horch, Elliott; Jenkins, Jon M.; Koch, David J.; Lissauer, Jack J.; Machalek, Pavel; Still, Martin; Welsh, William F.; Sanderfer, Dwight T.; Seader, Shawn E.; Smith, Jeffrey C.; Thompson, Susan E.; Twicken, Joseph D.

    2011-11-01

    We report the discovery of Kepler-15b (KOI-128), a new transiting exoplanet detected by NASA's Kepler mission. The transit signal with a period of 4.94 days was detected in the quarter 1 (Q1) Kepler photometry. For the first time, we have used the High Resolution Spectrograph (HRS) at the Hobby-Eberly Telescope (HET) to determine the mass of a Kepler planet via precise radial velocity (RV) measurements. The 24 HET/HRS RVs and 6 additional measurements from the Fibre-fed Échelle Spectrograph spectrograph at the Nordic Optical Telescope reveal a Doppler signal with the same period and phase as the transit ephemeris. We used one HET/HRS spectrum of Kepler-15 taken without the iodine cell to determine accurate stellar parameters. The host star is a metal-rich ([Fe/H] = 0.36 ± 0.07) G-type main-sequence star with T eff = 5515 ± 124 K. The semi-amplitude K of the RV orbit is 78.7+8.5 -9.5 m s-1, which yields a planet mass of 0.66 ± 0.1 M Jup. The planet has a radius of 0.96 ± 0.06 R Jup and a mean bulk density of 0.9 ± 0.2 g cm-3. The radius of Kepler-15b is smaller than the majority of transiting planets with similar mass and irradiation level. This suggests that the planet is more enriched in heavy elements than most other transiting giant planets. For Kepler-15b we estimate a heavy element mass of 30-40 M ⊕. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

  18. Nucleosynthesis in helium-enriched asymptotic giant branch models: Implications for heavy element enrichment in ω Centauri

    SciTech Connect

    Karakas, Amanda I.; Marino, Anna F.; Nataf, David M.

    2014-03-20

    We investigate the effect of helium enrichment on the evolution and nucleosynthesis of low-mass asymptotic giant branch (AGB) stars of 1.7 M {sub ☉} and 2.36 M {sub ☉} with a metallicity of Z = 0.0006 ([Fe/H] ≈–1.4). We calculate evolutionary sequences with the primordial helium abundance (Y = 0.24) and with helium-enriched compositions (Y = 0.30, 0.35, 0.40). For comparison, we calculate models of the same mass but at a lower metallicity Z = 0.0003 ([Fe/H] ≈–1.8) with Y = 0.24. Post-processing nucleosynthesis calculations are performed on each of the evolutionary sequences to determine the production of elements from hydrogen to bismuth. Elemental surface abundance predictions and stellar yields are presented for each model. The models with enriched helium have shorter main sequence and AGB lifetimes, and they enter the AGB with a more massive hydrogen-exhausted core than the primordial helium model. The main consequences are as follows: (1) low-mass AGB models with enhanced helium will evolve more than twice as fast, giving them the chance to contribute sooner to the chemical evolution of the forming globular clusters, and (2) the stellar yields will be strongly reduced relative to their primordial helium counterparts. An increase of ΔY = 0.10 at a given mass decreases the yields of carbon by up to ≈60% and of fluorine by up to 80%; it also decreases the yields of the s-process elements barium and lanthanum by ≈45%. While the yields of first s-process peak elements strontium, yttrium, and zirconium decrease by up to 50%, the yields of rubidium either do not change or increase.

  19. Cosmic-ray Heavy-element Spectra Over an Extended Energy Range from the Advanced Composition Explorer

    NASA Astrophysics Data System (ADS)

    Wiedenbeck, M. E.; Binns, W. R.; Christian, E. R.; Cummings, A. C.; Davis, A. J.; de Nolfo, G. A.; Israel, M. H.; Leske, R. A.; Labrador, A. W.; Mewaldt, R. A.; Stone, E. C.; von Rosenvinge, T. T.

    2016-12-01

    The Cosmic Ray Isotope Spectrometer (CRIS) on NASA's Advanced Composition Explorer (ACE) spacecraft has been measuring energy spectra and elemental and isotopic composition of galactic cosmic rays (GCRs) since ACE was launched in August 1997. Using measurements of nuclei that stop in thick stacks of silicon detectors, spectra are obtained for all elements from B through Ni. Typical energy coverage extends from 60 to 280 MeV/nuc for oxygen and 115 to 570 MeV/nuc for iron. Energy spectra of GCR nuclei observed near Earth have an intensity peak around several hundred MeV/nuc that is caused by the combined effects of ionization energy loss plus energy-dependent diffusion in the interstellar medium and solar modulation in the heliosphere. While the stopping-particle data provide precise measurements of the spectral roll-off on the low-energy side of the peak, they do not extend to high enough energy to precisely determine the peak shape and location. In addition to the stopping-particle measurements, CRIS routinely collects data on higher energy nuclei that penetrate the entire thickness of the silicon stacks. We have analyzed 18 years of penetrating-particle data using a new technique that achieves clean separation of even individual rare elements such as F and Sc and allows us to extend the CRIS measurements of GCR energy spectra to above the peak. We will discuss this analysis technique and present CRIS elemental energy spectra over a wider energy range than has previously been possible. We will also compare the spectra with predictions of a model calculation of the effects of interstellar and heliospheric transport.

  20. Nucleosynthesis in Helium-enriched Asymptotic Giant Branch Models: Implications for Heavy Element Enrichment in ω Centauri

    NASA Astrophysics Data System (ADS)

    Karakas, Amanda I.; Marino, Anna F.; Nataf, David M.

    2014-03-01

    We investigate the effect of helium enrichment on the evolution and nucleosynthesis of low-mass asymptotic giant branch (AGB) stars of 1.7 M ⊙ and 2.36 M ⊙ with a metallicity of Z = 0.0006 ([Fe/H] ≈-1.4). We calculate evolutionary sequences with the primordial helium abundance (Y = 0.24) and with helium-enriched compositions (Y = 0.30, 0.35, 0.40). For comparison, we calculate models of the same mass but at a lower metallicity Z = 0.0003 ([Fe/H] ≈-1.8) with Y = 0.24. Post-processing nucleosynthesis calculations are performed on each of the evolutionary sequences to determine the production of elements from hydrogen to bismuth. Elemental surface abundance predictions and stellar yields are presented for each model. The models with enriched helium have shorter main sequence and AGB lifetimes, and they enter the AGB with a more massive hydrogen-exhausted core than the primordial helium model. The main consequences are as follows: (1) low-mass AGB models with enhanced helium will evolve more than twice as fast, giving them the chance to contribute sooner to the chemical evolution of the forming globular clusters, and (2) the stellar yields will be strongly reduced relative to their primordial helium counterparts. An increase of ΔY = 0.10 at a given mass decreases the yields of carbon by up to ≈60% and of fluorine by up to 80%; it also decreases the yields of the s-process elements barium and lanthanum by ≈45%. While the yields of first s-process peak elements strontium, yttrium, and zirconium decrease by up to 50%, the yields of rubidium either do not change or increase.

  1. Investigation of Generation, Acceleration, Transport and Final Focusing of High-Intensity Heavy Ion Beams from Sources to Targets

    SciTech Connect

    Chiping Chen

    2006-10-26

    Under the auspices of the research grant, the Intense Beam Theoretical Research Goup at Massachusetts Institute of Technology's Plasma Science and Fusion Center made significant contributions in a number of important areas in the HIF and HEDP research, including: (a) Derivation of rms envelope equations and study of rms envelope dynamics for high-intensity heavy ion beams in a small-aperture AG focusing transport systems; (b) Identification of a new mechanism for chaotic particle motion, halo formation, and beam loss in high-intensity heavy ion beams in a small-aperture AG focusing systems; Development of elliptic beam theory; (d) Study of Physics Issues in the Neutralization Transport Experiment (NTX).

  2. Combining Hi-C data with phylogenetic correlation to predict the target genes of distal regulatory elements in human genome.

    PubMed

    Lu, Yulan; Zhou, Yuanpeng; Tian, Weidong

    2013-12-01

    Defining the target genes of distal regulatory elements (DREs), such as enhancer, repressors and insulators, is a challenging task. The recently developed Hi-C technology is designed to capture chromosome conformation structure by high-throughput sequencing, and can be potentially used to determine the target genes of DREs. However, Hi-C data are noisy, making it difficult to directly use Hi-C data to identify DRE-target gene relationships. In this study, we show that DREs-gene pairs that are confirmed by Hi-C data are strongly phylogenetic correlated, and have thus developed a method that combines Hi-C read counts with phylogenetic correlation to predict long-range DRE-target gene relationships. Analysis of predicted DRE-target gene pairs shows that genes regulated by large number of DREs tend to have essential functions, and genes regulated by the same DREs tend to be functionally related and co-expressed. In addition, we show with a couple of examples that the predicted target genes of DREs can help explain the causal roles of disease-associated single-nucleotide polymorphisms located in the DREs. As such, these predictions will be of importance not only for our understanding of the function of DREs but also for elucidating the causal roles of disease-associated noncoding single-nucleotide polymorphisms.

  3. The heaviest elements

    SciTech Connect

    Hoffman, D.C. Lawrence Berkeley Lab., CA )

    1994-05-02

    How long does an atom need to exist before it's possible to do any meaningful chemistry on it Is it possible to learn anything at all about the reactions of an element for which no more than a few dozen atoms have ever existed simultaneously These are some of the questions colleagues in a few laboratories worldwide attempt to answer as they investigate the chemistry of the heaviest elements--elements produced one atom at a time in accelerators by bombarding radioactive targets with high-intensity beams of heavy ions. All of these elements spontaneously decay; the most stable of them have half-lives of only a few minutes, some that are less stable exist for only milliseconds. So far, no chemical studies have been performed on elements whose longest lived isotopes last only milliseconds because the difficulties of doing chemistry on this time scale under highly radioactive conditions are enormous. Over the past 10 years, however, nuclear chemists have developed new techniques or adapted existing ones to begin to probe the chemical properties of those very heavy elements that have half-lives in the range of seconds to minutes. Although the classic experiments are now nearly 40 years old, they are worth describing, as they were the first of their kind and illustrate many of the techniques that are still used and essential in studying these very short-lived, radioactive elements.

  4. The Nrf2-antioxidant response element pathway: a target for regulating energy metabolism

    USDA-ARS?s Scientific Manuscript database

    The nuclear factor E2-related factor 2 (Nrf2) is a transcription factor that responds to oxidative stress by binding to the antioxidant response element (ARE) in the promoter of genes coding for antioxidant enzymes like NAD(P)H:quinone oxidoreductase 1 (NQO1) and proteins for glutathione synthesis. ...

  5. Different behaviours in phytoremediation capacity of two heavy metal tolerant poplar clones in relation to iron and other trace elements.

    PubMed

    Baldantoni, Daniela; Cicatelli, Angela; Bellino, Alessandro; Castiglione, Stefano

    2014-12-15

    Plant biodiversity and intra-population genetic variability have not yet been properly exploited in the framework of phytoremediation and soil reclamation. For this reason, iron and other metal accumulation capacity of two Cu and Zn tolerant poplar clones, namely AL22 (Populus alba L.) and N12 (Populus nigra L.), was investigated in a pot experiment. Cuttings of the two clones were planted in iron rich soil collected from an urban-industrial area. Concentrations of Cd, Cu, Fe, Pb and Zn were analysed in leaves (at different times), as well as in stems and in roots (at the end of the experiment), both in control plants and in plants grown on a soil whose Fe availability was artificially enhanced. Results showed that Cd and Zn were preferentially accumulated in leaves, whereas Cu, Fe and Pb were mainly accumulated in roots. The main differences in metal accumulation between clones were related to Cd (about tenfold higher concentrations in N12) and Cu (higher concentrations in AL22). Once soil Fe availability was enhanced, the uptake and accumulation of all metals declined, with the exception of Fe at the first sampling time in AL22 leaves. The different behaviour of the two poplar clones suggests that a thoughtful choice should be made for their use in relation to soil heavy metal remediation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. A multi-element screening method to identify metal targets for blood biomonitoring in green sea turtles (Chelonia mydas).

    PubMed

    Villa, C A; Finlayson, S; Limpus, C; Gaus, C

    2015-04-15

    Biomonitoring of blood is commonly used to identify and quantify occupational or environmental exposure to chemical contaminants. Increasingly, this technique has been applied to wildlife contaminant monitoring, including for green turtles, allowing for the non-lethal evaluation of chemical exposure in their nearshore environment. The sources, composition, bioavailability and toxicity of metals in the marine environment are, however, often unknown and influenced by numerous biotic and abiotic factors. These factors can vary considerably across time and space making the selection of the most informative elements for biomonitoring challenging. This study aimed to validate an ICP-MS multi-element screening method for green turtle blood in order to identify and facilitate prioritisation of target metals for subsequent fully quantitative analysis. Multi-element screening provided semiquantitative results for 70 elements, 28 of which were also determined through fully quantitative analysis. Of the 28 comparable elements, 23 of the semiquantitative results had an accuracy between 67% and 112% relative to the fully quantified values. In lieu of any available turtle certified reference materials (CRMs), we evaluated the use of human blood CRMs as a matrix surrogate for quality control, and compared two commonly used sample preparation methods for matrix related effects. The results demonstrate that human blood provides an appropriate matrix for use as a quality control material in the fully quantitative analysis of metals in turtle blood. An example for the application of this screening method is provided by comparing screening results from blood of green turtles foraging in an urban and rural region in Queensland, Australia. Potential targets for future metal biomonitoring in these regions were identified by this approach. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Enhancer connectome in primary human cells identifies target genes of disease-associated DNA elements.

    PubMed

    Mumbach, Maxwell R; Satpathy, Ansuman T; Boyle, Evan A; Dai, Chao; Gowen, Benjamin G; Cho, Seung Woo; Nguyen, Michelle L; Rubin, Adam J; Granja, Jeffrey M; Kazane, Katelynn R; Wei, Yuning; Nguyen, Trieu; Greenside, Peyton G; Corces, M Ryan; Tycko, Josh; Simeonov, Dimitre R; Suliman, Nabeela; Li, Rui; Xu, Jin; Flynn, Ryan A; Kundaje, Anshul; Khavari, Paul A; Marson, Alexander; Corn, Jacob E; Quertermous, Thomas; Greenleaf, William J; Chang, Howard Y

    2017-09-25

    The challenge of linking intergenic mutations to target genes has limited molecular understanding of human diseases. Here we show that H3K27ac HiChIP generates high-resolution contact maps of active enhancers and target genes in rare primary human T cell subtypes and coronary artery smooth muscle cells. Differentiation of naive T cells into T helper 17 cells or regulatory T cells creates subtype-specific enhancer-promoter interactions, specifically at regions of shared DNA accessibility. These data provide a principled means of assigning molecular functions to autoimmune and cardiovascular disease risk variants, linking hundreds of noncoding variants to putative gene targets. Target genes identified with HiChIP are further supported by CRISPR interference and activation at linked enhancers, by the presence of expression quantitative trait loci, and by allele-specific enhancer loops in patient-derived primary cells. The majority of disease-associated enhancers contact genes beyond the nearest gene in the linear genome, leading to a fourfold increase in the number of potential target genes for autoimmune and cardiovascular diseases.

  8. Targeted Killing as an Element of U.S. Foreign Policy in the War On Terror

    DTIC Science & Technology

    2006-05-25

    at http://www.washington times.com/commentary/20040325-091452-7923r.htm16 Jan 2006. Cohen, William S. Statement to the National Commission on...cfrterrorism.org/policy/assassination.html 26 Jan 2006. David, Steven R. “Fatal Choices: Israel’s Policy of Targeted Killing.” The Begin-Sadat Center...Relations, 20 Jan 2006. Accessed online at http://www.cfr.org/publication/9627/targeted_killings.html 26 Jan 2006. Kaufman, Whit. “The Ethics of

  9. The production of stress ethylene relative to the concentration of heavy metals and other elements in the lichen Hypogymnia physodes

    SciTech Connect

    Garty, J.; Kauppi, M.; Kauppi, A.

    1997-11-01

    The objective of this study was to examine fluctuations in the production of ethylene by the lichen, Hypogymnia physodes, indicative of environmental stress caused by air pollutants. In addition, the authors investigated the accumulation capacity of H. physodes, transplanted in the vicinity of two streets having slow traffic and a highway in the city of Oulu, N. Finland, for a short period (45 d). The amounts of stress ethylene produced by the transplanted lichens was compared with the amounts of airborne elements accumulated in the thallus. H. physodes manifested a high accumulation capacity for Fe and Mg in thalli exposed in either one or both streets with slow traffic in Oulu in comparison with thalli left on the control site in the forest outside of the city. Two of the observed elements, Zn and Fe, exhibited a significant positive correlation with the ethylene concentration detected concomitant in thalli retrieved from one or both streets with slow traffic were higher than the concentrations in thalli transplanted in a highway with 25,240 cars/d after 45 d of exposure. The data thus suggest that the streets with slow traffic and fewer cars are more polluted than the highway.

  10. Batch leaching tests of motherboards to assess environmental contamination by bromine, platinum group elements and other selected heavy metals.

    PubMed

    Almeida, César; Grosselli, Melina; González, Patricia; Martínez, Dante; Gil, Raúl

    2016-02-01

    In this study, a batch leaching test was executed to evaluate the toxicity associated with chemicals contained in motherboards. The leaching solutions used were distilled water, nitric acid, acetic acid and synthetic acid rain solution. A total of 21 elements including Ag, As, Au, Br, Cd, Co, Cr, Cu, Hf, Ir, Mn, Ni, Os, Pb, Pd, Pt, Rd, Rh, Se, U and Zn were analyzed. In this study, the pH values of all the leachates fell within the range of 2.33-4.88. The highest concentrations of metals were obtained from the acid rain solution, whilst the maximum value of bromine was achieved with solution of acetic acid. Appreciable concentrations of platinum group elements were detected with concentrations around 3.45, 1.43, 1.21 and 22.19 µg L(-1) for Ir, Pd, Pt and Rh, respectively. The different leaching of the motherboards revealed the predominant presence of the toxic substances in the leached from the e-waste. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Downstream Regulatory Element Antagonist Modulator (DREAM), a target for anti-thrombotic agents.

    PubMed

    Cho, Jaehyung

    2017-03-01

    Circulating platelets participate in the process of numerous diseases including thrombosis, inflammation, and cancer. Thus, it is of great importance to understand the underlying mechanisms mediating platelet activation under disease conditions. Emerging evidence indicates that despite the lack of a nucleus, platelets possess molecules that are involved in gene transcription in nucleated cells. This review will summarize downstream regulatory element antagonist modulator (DREAM), a transcriptional repressor, and highlight recent findings suggesting its novel non-transcriptional role in hemostasis and thrombosis.

  12. Distribution and mobility of heavy elements in floodplain agricultural soils along the Ibar River (Southern Serbia and Northern Kosovo). Chemometric investigation of pollutant sources and ecological risk assessment.

    PubMed

    Barać, Nemanja; Škrivanj, Sandra; Bukumirić, Zoran; Živojinović, Dragana; Manojlović, Dragan; Barać, Milan; Petrović, Rada; Ćorac, Aleksandar

    2016-05-01

    This work investigates the influence of a high-magnitude flood event on heavy elements (HEs) pollution and mobility in the agricultural soils along Ibar River in Southern Serbia and Northern Kosovo. The study area was one of the most important Pb/Zn industrial regions in Europe. Soil samples (n = 50) collected before and after the floods in May 2014 were subjected to the sequential extraction procedure proposed by the Community Bureau of Reference (BCR). The results indicated that the floods significantly increased not only the pseudo total concentrations of HEs in the soil but also their mobile and potentially bioavailable amounts. Moreover, higher concentrations (both pseudo total and potentially bioavailable) were found in the agricultural soils closer to the industrial hotspots. Principal component analysis and hierarchical cluster analysis successfully grouped the analyzed elements according to their anthropogenic or natural origin. The floods significantly increased the potential ecological risk of HEs associated with Pb/Zn industrial activities in the study area. The potential ecological risk of Cd after the floods was highest and should be of special concern.

  13. Study the chemical composition and biological outcomes resulting from the interaction of the hormone adrenaline with heavy elements: Infrared, Raman, electronic, 1H NMR, XRD and SEM studies

    NASA Astrophysics Data System (ADS)

    Ibrahim, Omar B.; Mohamed, Mahmoud A.; Refat, Moamen S.

    2014-01-01

    Heavy metal adrenaline complexes formed from the reaction of adrenaline with Al3+, Zn2+, Sn2+, Sb3+, Pb2+and Bi3+ ions in methanolic solvent at 60 °C. The final reaction products have been isolated and characterization using elemental analyses (% of carbon, hydrogen and nitrogen), conductivity measurements, mid infrared, Raman laser, UV-Vis, 1H NMR spectra, X-ray powder diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDX). Upon the spectroscopic, conductivity and elemental analyses, the stoichiometric reactions indicated that the data obtained refer to 1:2 (M:L) for Zn2+, Sn2+, Pb2+and Bi3+ complexes [Zn(Adr)2(Cl)2], [Sn(Adr)2]Cl2, [Pb(Adr)2](NO3)2 and [Bi(Adr)2(Cl)2]Cl, while the molar ratio 1:3 (M:L) for Al3+ and Sb3+ with formulas [Al(Adr)3](NO3)3 and [Sb(Adr)3]Cl3. The infrared and Raman laser spectra interpreted the mode of interactions which associated through the two phenolic groups of catechol moiety. The adrenaline chelates have been screened for their in vitro antibacterial activity against four bacteria, Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and two strains of fungus (Aspergillus flavus and Candida albicans). The metal chelates were shown to possess more antibacterial and antifungal activities than the free adrenaline chelate.

  14. Multiple muscle-specific regulatory elements are associated with a DNase I hypersensitive site of the cardiac beta-myosin heavy-chain gene.

    PubMed

    Huang, W Y; Chen, J J; Shih, N; Liew, C C

    1997-10-15

    Using nuclei isolated from neonatal cardiomyocytes, we have mapped the DNase I hypersensitive sites (DHSs) residing within the 5'-upstream regions of the hamster cardiac myosin heavy-chain (MyHC) gene. Two cardiac-specific DHSs within the 5 kb upstream region of the cardiac MyHC gene were identified. One of the DHSs was mapped to the -2.3 kb (beta-2.3 kb) region and the other to the proximal promoter region. We further localized the beta-2.3 kb site to a range of 250 bp. Multiple, conserved, muscle regulatory motifs were found within the beta-2.3 kb site, consisting of three E-boxes, one AP-2 site, one CArG motif, one CT/ACCC box and one myocyte-specific enhancer factor-2 site. This cluster of regulatory elements is strikingly similar to a cluster found in the enhancer of the mouse muscle creatine kinase gene (-1256 to -1050). The specific interaction of the motifs within the beta-2.3 kb site and the cardiac nuclear proteins was demonstrated using gel mobility-shift assays and footprinting analysis. In addition, transfection analysis revealed a significant increase in chloramphenicol acetyltransferase activity when the beta-2.3 kb site was linked to a heterologous promoter. These results suggest that previously undefined regulatory elements of the beta-MyHC gene may be associated with the beta-2.3 kb site.

  15. Over Target Baseline: Lessons Learned from the NASA SLS Booster Element

    NASA Technical Reports Server (NTRS)

    Carroll, Truman J.

    2016-01-01

    Goal of the presentation is to teach, and then model, the steps necessary to implement an Over Target Baseline (OTB). More than a policy and procedure session, participants will learn from recent first hand experience the challenges and benefits that come from successfully executing an OTB.

  16. Demystifying the secret mission of enhancers: linking distal regulatory elements to target genes

    PubMed Central

    Yao, Lijing; Berman, Benjamin P.; Farnham, Peggy J.

    2015-01-01

    Abstract Enhancers are short regulatory sequences bound by sequence-specific transcription factors and play a major role in the spatiotemporal specificity of gene expression patterns in development and disease. While it is now possible to identify enhancer regions genomewide in both cultured cells and primary tissues using epigenomic approaches, it has been more challenging to develop methods to understand the function of individual enhancers because enhancers are located far from the gene(s) that they regulate. However, it is essential to identify target genes of enhancers not only so that we can understand the role of enhancers in disease but also because this information will assist in the development of future therapeutic options. After reviewing models of enhancer function, we discuss recent methods for identifying target genes of enhancers. First, we describe chromatin structure-based approaches for directly mapping interactions between enhancers and promoters. Second, we describe the use of correlation-based approaches to link enhancer state with the activity of nearby promoters and/or gene expression. Third, we describe how to test the function of specific enhancers experimentally by perturbing enhancer–target relationships using high-throughput reporter assays and genome editing. Finally, we conclude by discussing as yet unanswered questions concerning how enhancers function, how target genes can be identified, and how to distinguish direct from indirect changes in gene expression mediated by individual enhancers. PMID:26446758

  17. Comparison of Digestion Methods for the Determination of Trace Elements and Heavy Metals in Human Hair and Nails

    PubMed Central

    Ishak, Ismarulyusda; Rosli, Farah Dayana; Mohamed, Jamaludin; Mohd Ismail, Muhammad Faiz

    2015-01-01

    Background Microwave is the most reliable sample digestion method. However, it requires expensive microwave digester automation and has relatively low productivity. In this study, three non-automated digestion methods, i.e. wet acid digestion using nitric acid (HNO3) and hydrogen peroxide (H2O2), wet acid digestion using HNO3, and dry washing, are compared in order to determine the best approach. Methods Certified reference material IAEA-086 (International Atomic Energy Agency, Austria) and hair and nail samples from 20 female students of Universiti Kebangsaan Malaysia, aged 19 to 30 years, were collected and analysed using the three digestion methods. Results For hair samples, analysis of variance of repeated measures showed significant differences in the level of all elements (P < 0.001) between the three methods. For nail samples, only the copper (Cu) level showed no significant difference (P = 0.100) between methods. Wet acid digestion using HNO3 and H2O2 showed the best within- and between-run relative standard deviation (RSD) values, with within-run RSD for all elements, except for selenium (Se), < 5%. The between-run precision ranges from 6.14% to 17.96% for hair and from 3.53% to 11.52% for nail samples. Wet acid digestion using HNO3 and H2O2 showed both good accuracy and precision for manganese (Mn) and magnesium (Mg), with percentage recoveries of 110% and 96.9%, respectively. All elements show higher method detection limit (MDL) values than the previous study: 0.05 μg/g Mg for wet acid digestion using HNO3, 0.02 μg/g Se for wet acid digestion using HNO3 and H2O2, and 0.2 μg/g Mg for dry ash method. Conclusion Wet acid digestion using HNO3 and H2O2 proved to be the best method in terms of precision, accuracy, recovery, and MDL. However, only Mn and Mg showed adequate precision, accuracy, and percentage of recovery. PMID:28223880

  18. Identification and Characterization of Putative Integron-Like Elements of the Heavy-Metal-Hypertolerant Strains of Pseudomonas spp.

    PubMed

    Ciok, Anna; Adamczuk, Marcin; Bartosik, Dariusz; Dziewit, Lukasz

    2016-11-28

    Pseudomonas strains isolated from the heavily contaminated Lubin copper mine and Zelazny Most post-flotation waste reservoir in Poland were screened for the presence of integrons. This analysis revealed that two strains carried homologous DNA regions composed of a gene encoding a DNA_BRE_C domain-containing tyrosine recombinase (with no significant sequence similarity to other integrases of integrons) plus a three-component array of putative integron gene cassettes. The predicted gene cassettes encode three putative polypeptides with homology to (i) transmembrane proteins, (ii) GCN5 family acetyltransferases, and (iii) hypothetical proteins of unknown function (homologous proteins are encoded by the gene cassettes of several class 1 integrons). Comparative sequence analyses identified three structural variants of these novel integron-like elements within the sequenced bacterial genomes. Analysis of their distribution revealed that they are found exclusively in strains of the genus Pseudomonas.

  19. A New Gas Stopper for Heavy Element Chemistry Research at the Texas A&M University Cyclotron Institute

    NASA Astrophysics Data System (ADS)

    Alfonso, Marisa; Tereshatov, Evgeny; Devanzo, Michael; Sefcik, Jordan; Bennett, Megan; Mayorov, Dmitriy; Werke, Tyler; Folden, Charles

    2014-09-01

    A Recoil Transfer Chamber (RTC) to facilitate the chemical study of the heaviest elements, created via fusion-evaporation reactions, has been fabricated at the Cyclotron Institute at Texas A&M University. This gas stopper is a hybrid of previously used RTCs in the transactinide field and one used at Michigan State University for stopping products from projectile fragmentation reactions. Our RTC uses laminar gas flow and a series of electrodes that create a potential gradient to efficiently transport evaporation residues to an appropriate chemistry experiment. The RTC was characterized offline using 216Po recoils from a 228Th source and online using a high cross section fusion-evaporation reaction, 118Sn(40Ar, 6n)152Er. Results show an online extraction efficiency of (70 +/ - 9)%, which is comparable to devices used worldwide. This talk will discuss the design of the RTC and present results from offline and online experiments.

  20. Quantitative Evaluation of Heavy Metals and Trace Elements in the Urinary Bladder: Comparison Between Cancerous, Adjacent Non-cancerous and Normal Cadaveric Tissue.

    PubMed

    Abdel-Gawad, Mahmoud; Elsobky, Emad; Shalaby, Mahmoud M; Abd-Elhameed, Mohamed; Abdel-Rahim, Mona; Ali-El-Dein, Bedeir

    2016-12-01

    The role of heavy metals and trace elements (HMTE) in the development of some cancers has been previously reported. Bladder carcinoma is a frequent malignancy of the urinary tract. The most common risk factors for bladder cancer are exposure to industrial carcinogens, cigarette smoking, gender, and possibly diet. The aim of this study was to evaluate HTME concentrations in the cancerous and adjacent non-cancerous tissues and compare them with those of normal cadaveric bladder. This prospective study included 102 paired samples of full-thickness cancer and adjacent non-cancerous bladder tissues of radical cystectomy (RC) specimens that were histologically proven as invasive bladder cancer (MIBC). We used 17 matched controls of non-malignant bladder tissue samples from cadavers. All samples were processed and evaluated for the concentration of 22 HMTE by using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Outcome analysis was made by the Mann-Whitney U, chi-square, Kruskal-Wallis, and Wilcoxon signed ranks tests. When compared with cadaveric control or cancerous, the adjacent non-cancerous tissue had higher levels of six elements (arsenic, lead, selenium, strontium, zinc, and aluminum), and when compared with the control alone, it had a higher concentration of calcium, cadmium, chromium, potassium, magnesium, and nickel. The cancerous tissue had a higher concentration of cadmium, lead, chromium, calcium, potassium, phosphorous, magnesium, nickel, selenium, strontium, and zinc than cadaveric control. Boron level was higher in cadaveric control than cancerous and adjacent non-cancerous tissue. Cadmium level was higher in cancerous tissue with node-positive than node-negative cases. The high concentrations of cadmium, lead, chromium, nickel, and zinc, in the cancerous together with arsenic in the adjacent non-cancerous tissues of RC specimens suggest a pathogenic role of these elements in BC. However, further work-up is needed to support this

  1. Water contamination with heavy metals and trace elements from Kilembe copper mine and tailing sites in Western Uganda; implications for domestic water quality.

    PubMed

    Abraham, Mwesigye R; Susan, Tumwebaze B

    2017-02-01

    The mining and processing of copper in Kilembe, Western Uganda, from 1956 to 1982 left over 15 Mt of cupriferous and cobaltiferous pyrite dumped within a mountain river valley, in addition to mine water which is pumped to the land surface. This study was conducted to assess the sources and concentrations of heavy metals and trace elements in Kilembe mine catchment water. Multi-element analysis of trace elements from point sources and sinks was conducted which included mine tailings, mine water, mine leachate, Nyamwamba River water, public water sources and domestic water samples using ICP-MS. The study found that mean concentrations (mg kg(-1)) of Co (112), Cu (3320), Ni (131), As (8.6) in mine tailings were significantly higher than world average crust and were being eroded and discharged into water bodies within the catchment. Underground mine water and leachate contained higher mean concentrations (μg L(-1)) of Cu (9470), Co (3430) and Ni (590) compared with background concentrations (μg L(-1)) in un contaminated water of 1.9, 0.21 and 0.67 for Cu, Co and Ni respectively. Over 25% of household water samples exceeded UK drinking water thresholds for Al of 200 μg L(-1), Co exceeded Winsconsin (USA drinking) water thresholds of 40 μg L(-1) in 40% of samples while Fe in 42% of samples exceeded UK thresholds of 200 μg L(-1). The study however found that besides mining activities, natural processes of geological weathering also contributed to Al, Fe, and Mn water contamination in a number of public water sources.

  2. Autoregulation of fos: the dyad symmetry element as the major target of repression.

    PubMed Central

    König, H; Ponta, H; Rahmsdorf, U; Büscher, M; Schönthal, A; Rahmsdorf, H J; Herrlich, P

    1989-01-01

    Fos and Jun co-operatively repress the fos promoter. Removal of all putative Fos/Jun binding sites from the fos promoter neither obliterates the repression by Fos/Jun in transient cotransfection experiments in NIH3T3 cells nor the turn-off kinetics of serum-induced fos expression in stably transfected NIH3T3 cells. The dyad symmetry element (DSE) suffices to subject a promoter to this type of repression. However, one of the putative Fos/Jun binding sites (-292 to -299 and thus located immediately adjacent to the DSE), determines the very low level of basal expression. Images PMID:2511006

  3. Targeting a Regulatory Element in Human Thymidylate Synthase mRNA

    PubMed Central

    Brunn, Nicholas D.; Sega, Emily Garcia; Kao, Melody B.

    2013-01-01

    Thymidylate synthase (TS) is a key enzyme in the biosynthesis of thymidine. TS inhibitors, which are used in cancer chemotherapy, suffer from resistance development in tumors through upregulation of TS expression. Autoregulatory translation control has been implicated with TS overexpression. TS binding at its own mRNA, which leads to sequestration of the start codon, is abolished when the enzyme forms an inhibitor complex, thereby relieving translation suppression. We have used the protein binding site from the TS mRNA in the context of a bicistronic expression system to validate targeting the regulatory motif with stabilizing ligands that prevent ribosomal initiation. Stabilization of the RNA by mutations, which were studied as surrogates of ligand binding, suppresses translation of the TS protein. Compounds that stabilize the TS binding RNA motif and thereby inhibit ribosomal initiation might be used in combination with existing TS enzyme-targeting drugs to overcome resistance development during chemotherapy. PMID:23143777

  4. Fragmentation Cross Sections of 290 and 400 MeV/nucleon 12C Beamson Elemental Targets

    SciTech Connect

    Zeitlin, C.; Guetersloh, S.; Heilbronn, L.; Miller, J.; Fukumura,A.; Iwata, Y.; Murakami, T.

    2007-03-17

    Charge-changing and fragment production cross sections at 0circ have been obtained for interactions of 290 MeV/nucleon and 400MeV/nucleon carbon beams with C, CH2, Al, Cu, Sn, and Pb targets. Thesebeams are relevant to cancer therapy, space radiation, and the productionof radioactive beams. We compare to previously published results using Cand CH2 targets at similar beam energies. Due to ambiguities arising fromthe presence of multiple fragments on many events, previous publicationshave reported only cross sections for B and Be fragments. In this work wehave extracted cross sections for all fragment species, using dataobtained at three distinct values of angular acceptance, supplemented bydata taken with the detector stack placed off the beam axis. A simulationof the experiment with the PHITS Monte Carlo code shows fair agreementwith the data obtained with the large acceptance detectors, but agreementis poor at small acceptance. The measured cross sections are alsocompared to the predictions of the one-dimensional cross section modelsEPAX2 and NUCFRG2; the latter is presently used in NASA's space radiationtransport calculations. Though PHITS and NUCFRG2 reproduce thecharge-changing cross sections with reasonable accuracy, none of themodels is able to accurately predict the fragment cross sections for allfragment species and target materials.

  5. Production of neutron-rich nuclides in the heavy-element region via /sup 3/He-induced reactions

    SciTech Connect

    Chu, Y.Y.; Zhou, M.L.

    1982-01-01

    We have measured the production cross sections for /sup 233/Th and /sup 231/Th from the bombardment of /sup 238/U with /sup 3/He ions at 46-, 53-, and 60-MeV at the Brookhaven 60-in. isochronous cyclotron. We have also attempted to observe the decay of /sup 233/Ac produced via /sup 238/U(/sup 3/He,/sup 8/B) or equivalent reactions using 61 MeV /sup 3/He ions by first separating thorium from actinium and then performing chemical purifications on the second thorium sample into which the actinium has decayed. In the four experiments we performed, three gave results consistent with the ..beta.. half-life of /sup 233/Ac somewhat longer than 120 s and the production cross section from this target-projectile combination in the order of 1 to 2 ..mu..b.

  6. Ecotoxicological characteristic of a soil polluted by radioactive elements and heavy metals before and after its bioremediation

    NASA Astrophysics Data System (ADS)

    Georgiev, P.; Groudev, S.; Spasova, I.; Nikolova, M.

    2012-04-01

    Cinnamon soils from southeastern Bulgaria are heavily polluted with radionuclides (uranium, radium) and toxic heavy metals (copper and lead) due to the winds transportation of fine particles from flotation dumps to the soil surface. As a result of this, the polluted soils are characterized by a slightly alkaline pH (7.82) and positive net neutralization potential (+136.8 kg CaCO3/t). A fresh sample of cinnamon soil was subjected to remediation under laboratory conditions in four lysimeters each containing 70 kg of soil. The preliminary study revealed that most of the pollutants were presented as carbonate, reducible and oxidisable mobility fractions, i.e. pollutants ions were specifically adsorbed by carbonate and ferric iron minerals or were capsulated in sulfides. The applied soil treatment was connected with leaching of the pollutants located mainly in the horizon A, their transportation through the soil profile as soluble forms, and their precipitation in the rich-in-clay subhorizon B3. The efficiency of leaching depended on the activity of the indigenous microflora and on the chemical processes connected with solubilization of pollutants and formation of stable complexes with some organic compounds, chloride and hydrocarbonate ions. These processes were considerably enhanced by adding hay to the horizon A and irrigating the soil with water solutions containing the above-mentioned ions and some nutrients. After 18 months of treatment, each of the soil profiles in the different lysimeters was divided into five sections reflecting the different soil layers. The soil in these sections was subjected to a detailed chemical analysis and the data obtained were compared with the relevant data obtained before the start of the experiment. The best leaching of pollutants from horizon A was measured in the variants where soil mulching was applied. For example, the best leaching of lead (54.5 %) was found in the variant combining this technique and irrigation with solutions

  7. Basic Research on the Composition of Heavy Cosmic Rays: The Trans-Iron Galactic Element Recorder Experiment (TIGER)

    NASA Technical Reports Server (NTRS)

    Binns, W. Robert

    2004-01-01

    Among the most fundamental astrophysical problems is understanding the mechanism by which particles are accelerated to the enormous energies observed in the cosmic rays. That problem can be conveniently divided into two questions: (1) What is the source of the energy and the mechanism for converting the energy of that source into the energy of individual cosmic-ray nuclei, and (2) what is the source of the material that is accelerated and the mechanism for injecting that material into the cosmic-ray accelerator? There is a general consensus that the answer to the first of these questions, for nuclei with energy eV, is that the source of their energy is almost certainly from supernova explosions (e.g., Ginzburg & Syrovatskii, 1964). The answer to the second question is still uncertain, although evidence in favor of a superbubble origin of cosmic rays is becoming quite significant (Higdon et al, 2203 and Binns, 2005 (Submitted to ApJ). There are several ways of interpreting available data that lead to quite different models for the source of the material and its injection mechanism. With the The Trans-Iron Galactic Element Recorder Experiment (TIGER) instrument we have obtained data that will help to distinguish among these possible models. In the report, the TIGER flights, the instrument itself, results, and a publication list as a result of the work are presented.

  8. Z-dependence analysis of M x-ray production cross sections for heavy elements with 60≤Z≤90 by protons impact

    SciTech Connect

    Deghfel, B.; Kahoul, A.; Nekkab, M.

    2015-03-30

    Motivated by the large deviation between the experiment and the predictions of the most often used model of ionization process by a charged particle, namely ECPSSR model, a large database of experimental M-shell X-ray production cross-sections by protons energies varying from 0.1 to 4.0 MeV for elements with atomic number 60 ≤ Z ≤ 90, is collected from various sources published from 1980 till 2009 to deduce an empirical M x-ray production cross section. This latter is then deduced from the available experimental data as a function of the scaled velocity parameter by using the whole range of elements (collective analysis) or by introducing the dependence of these cross sections on the atomic number of the target, noted as “Z-dependence analysis” in addition to the collective one. The corresponding results and their deviation from the experimental data are presented for selected elements. Also, a comparison is made for selected elements between our results and other theoretical as well as experimental works.

  9. Major Element Analysis of the Target Rocks at Meteor Crater, Arizona

    NASA Technical Reports Server (NTRS)

    See, Thomas H.; Hoerz, Friedrich; Mittlefehldt, David W.; Varley, Laura; Mertzman, Stan; Roddy, David

    2002-01-01

    We collected approximately 400 rock chips in continuous vertical profile at Meteor Crater, Arizona, representing, from bottom to top, the Coconino, Toroweap, Kaibab, and Moenkopi Formations to support ongoing compositional analyses of the impact melts and their stratigraphic source depth(s) and other studies at Meteor Crater that depend on the composition of the target rocks. These rock chips were subsequently pooled into 23 samples for compositional analysis by XRF (x ray fluorescence) methods, each sample reflecting a specific stratigraphic "subsection" approximately 5-10 in thick. We determined the modal abundance of quartz, dolomite, and calcite for the entire Kaibab Formation at vertical resolutions of 1-2 meters. The Coconino Formation composes the lower half of the crater cavity. It is an exceptionally pure sandstone. The Toroweap is only two inches thick and compositionally similar to Coconino, therefore, it is not a good compositional marker horizon. The Kaibab Formation is approximately 80 in thick. XRD (x ray diffraction) studies show that the Kaibab Formation is dominated by dolomite and quartz, albeit in highly variable proportions; calcite is a minor phase at best. The Kaibab at Meteor Crater is therefore a sandy dolomite rather than a limestone, consistent with pronounced facies changes in the Permian of SE Arizona over short vertical and horizontal distances. The Moenkopi forms the 12 in thick cap rock and has the highest Al2O3 and FeO concentrations of all target rocks. With several examples, we illustrate how this systematic compositional and modal characterization of the target ideologies may contribute to an understanding of Meteor Crater, such as the depth of its melt zone, and to impact cratering in general, such as the liberation of CO2 from shocked carbonates.

  10. Flux and dose transmission through concrete of neutrons from proton induced reactions on various target elements

    NASA Astrophysics Data System (ADS)

    Maiti, Moumita; Nandy, Maitreyee; Roy, S. N.; Sarkar, P. K.

    2004-12-01

    Simple empirical expressions for transmission of flux and dose through concrete are presented for neutrons from proton induced reactions. For this purpose the neutron emission from different targets in proton induced reactions in the energy range 25-200 MeV have been considered. The calculated effective dose outside a concrete shield shows overall good agreement with the effective dose estimated from measured neutron flux in the framework of the Moyer model. The calculated effective attenuation length shows a rising trend with incident proton energy and shield thickness.

  11. Macrophage Migration Inhibitory Factor as an Emerging Drug Target to Regulate Antioxidant Response Element System

    PubMed Central

    Yukitake, Hiroshi; Takizawa, Masayuki

    2017-01-01

    Oxidative stress is involved in pathophysiology and pathological conditions of numerous human diseases. Thus, understanding the mechanisms underlying the redox homeostasis in cells and organs is valuable for discovery of therapeutic drugs for oxidative stress-related diseases. Recently, by applying chemical biology approach with an ARE activator, BTZO-1, we found macrophage migration inhibitory factor (MIF) as a new regulator of antioxidant response element- (ARE-) mediated gene transcription. BTZO-1 and its active derivatives bound to MIF and protected cells and organs from oxidative insults via ARE activation in animal models with oxidative stress such as ischemia/reperfusion injury, inflammatory bowel diseases, and septic shock. In this review, we briefly highlight key findings in understanding the MIF-ARE system. PMID:28191280

  12. Emittance estimation by an ion optical element with variable focusing strength and a viewing target

    SciTech Connect

    Maeder, J.; Rossbach, J.; Maimone, F.; Spaedtke, P.; Tinschert, K.; Lang, R.; Sun, L.; Cao, Y.; Zhao, H.

    2010-02-15

    The emittance of an extracted ion beam can be estimated to first order by a series of three linear independent profile measurements. This estimation is restricted to the evaluation of an upper limit of the emittance value for a homogeneous, nonfilamented beam. The beam is assumed to be round, respectively elliptical, without any structure of the intensity distribution, no space charge has been assumed for the drifting beam, and the optics is assumed to be linear. Instead of using three different drift sections, a linear focusing element with three different focusing strengths can be used. Plotting the beam radius as function of focusing strength, three independent solutions can be used to calculate the Twiss parameters {alpha}, {beta}, and {gamma} and furthermore the emittance {epsilon}. Here we describe the measurements which have been performed with the SECRAL ion source at Institute of Modern Physics Lanzhou.

  13. CONSTRAINTS ON THE FORMATION OF THE GALACTIC BULGE FROM Na, Al, AND HEAVY-ELEMENT ABUNDANCES IN PLAUT's FIELD

    SciTech Connect

    Johnson, Christian I.; Rich, R. Michael; Kobayashi, Chiaki; Fulbright, Jon P. E-mail: rmr@astro.ucla.edu E-mail: jfulb@skysrv.pha.jhu.edu

    2012-04-20

    We report chemical abundances of Na, Al, Zr, La, Nd, and Eu for 39 red giant branch (RGB) stars and 23 potential inner disk red clump stars located in Plaut's low-extinction window. We also measure lithium for a super Li-rich RGB star. The abundances were determined by spectrum synthesis of high-resolution (R Almost-Equal-To 25,000), high signal-to-noise (S/N {approx} 50-100 pixel{sup -1}) spectra obtained with the Blanco 4 m telescope and Hydra multifiber spectrograph. For the bulge RGB stars, we find a general increase in the [Na/Fe] and [Na/Al] ratios with increasing metallicity, and a similar decrease in [La/Fe] and [Nd/Fe]. Additionally, the [Al/Fe] and [Eu/Fe] abundance trends almost identically follow those of the {alpha}-elements, and the [Zr/Fe] ratios exhibit relatively little change with [Fe/H]. The consistently low [La/Eu] ratios of the RGB stars indicate that at least a majority of bulge stars formed rapidly ({approx}<1 Gyr) and before the main s-process could become a significant pollution source. In contrast, we find that the potential inner disk clump stars exhibit abundance patterns more similar to those of the thin and thick disks. Comparisons between the abundance trends at different bulge locations suggest that the inner and outer bulges formed on similar timescales. However, we find evidence of some abundance differences between the most metal-poor and metal-rich stars in various bulge fields. The data also indicate that the halo may have had a more significant impact on the outer bulge initial composition than the inner bulge composition. The [Na/Fe], and to a lesser extent [La/Fe], abundances further indicate that the metal-poor bulge, at least at {approx}1 kpc from the Galactic center, and thick disk may not share an identical chemistry.

  14. Mechanical properties of UO2 thin films under heavy ion irradiation using nanoindentation and finite element modeling

    NASA Astrophysics Data System (ADS)

    Elbakhshwan, Mohamed S.; Miao, Yinbin; Stubbins, James F.; Heuser, Brent J.

    2016-10-01

    The mechanical response of UO2 to irradiation is becoming increasingly important due to the shift to higher burn-up rates in the next generation of nuclear reactors. In the current study, thin films of UO2 were deposited on YSZ substrates using reactive-gas magnetron sputtering. Nanoindentation was used to measure the mechanical properties of the as-grown and irradiated films. Finite element modeling was used to account for the substrate effect on the measurements. In order to study the effect of displacement cascades accompanying gas bubbles, 5000 Å UO2 films were irradiated with 600 keV Kr+ ions at 25 °C and 600 °C. These irradiation conditions were used to confine radiation damage effects and implanted gas within the film. Results showed an increase in the film hardness and yield strength with dose, while elastic modulus initially decreased with irradiation and then kept increasing with dose. The change in hardness and elastic modulus is attributed to the introduction of gas bubbles and displacement cascade damage. Irradiation at 600 °C resulted in a decrease in the hardness and elastic modulus after irradiation using 600 keV Kr+ at a dose of 1E14 ions/cm2. Both hardness and elastic modulus then increased with irradiation dose. This behavior is attributed to recrystallization during irradiation at 600 °C and the formation of nanocrystallite regions with diameter and density that increase with dose. The calculation of the critical resolved shear stress (CRSS) demonstrated that nanocrystals are the primary cause for film hardening based on the Orowan hardening mechanism.

  15. Ceramide-tamoxifen regimen targets bioenergetic elements in acute myelogenous leukemia.

    PubMed

    Morad, Samy A F; Ryan, Terence E; Neufer, P Darrell; Zeczycki, Tonya N; Davis, Traci S; MacDougall, Matthew R; Fox, Todd E; Tan, Su-Fern; Feith, David J; Loughran, Thomas P; Kester, Mark; Claxton, David F; Barth, Brian M; Deering, Tye G; Cabot, Myles C

    2016-07-01

    The objective of our study was to determine the mechanism of action of the short-chain ceramide analog, C6-ceramide, and the breast cancer drug, tamoxifen, which we show coactively depress viability and induce apoptosis in human acute myelogenous leukemia cells. Exposure to the C6-ceramide-tamoxifen combination elicited decreases in mitochondrial membrane potential and complex I respiration, increases in reactive oxygen species (ROS), and release of mitochondrial proapoptotic proteins. Decreases in ATP levels, reduced glycolytic capacity, and reduced expression of inhibitors of apoptosis proteins also resulted. Cytotoxicity of the drug combination was mitigated by exposure to antioxidant. Cells metabolized C6-ceramide by glycosylation and hydrolysis, the latter leading to increases in long-chain ceramides. Tamoxifen potently blocked glycosylation of C6-ceramide and long-chain ceramides. N-desmethyltamoxifen, a poor antiestrogen and the major tamoxifen metabolite in humans, was also effective with C6-ceramide, indicating that traditional antiestrogen pathways are not involved in cellular responses. We conclude that cell death is driven by mitochondrial targeting and ROS generation and that tamoxifen enhances the ceramide effect by blocking its metabolism. As depletion of ATP and targeting the "Warburg effect" represent dynamic metabolic insult, this ceramide-containing combination may be of utility in the treatment of leukemia and other cancers. Copyright © 2016 by the American Society for Biochemistry and Molecular Biology, Inc.

  16. Ceramide-tamoxifen regimen targets bioenergetic elements in acute myelogenous leukemia1

    PubMed Central

    Morad, Samy A. F.; Ryan, Terence E.; Neufer, P. Darrell; Zeczycki, Tonya N.; Davis, Traci S.; MacDougall, Matthew R.; Fox, Todd E.; Tan, Su-Fern; Feith, David J.; Loughran, Thomas P.; Kester, Mark; Claxton, David F.; Barth, Brian M.; Deering, Tye G.; Cabot, Myles C.

    2016-01-01

    The objective of our study was to determine the mechanism of action of the short-chain ceramide analog, C6-ceramide, and the breast cancer drug, tamoxifen, which we show coactively depress viability and induce apoptosis in human acute myelogenous leukemia cells. Exposure to the C6-ceramide-tamoxifen combination elicited decreases in mitochondrial membrane potential and complex I respiration, increases in reactive oxygen species (ROS), and release of mitochondrial proapoptotic proteins. Decreases in ATP levels, reduced glycolytic capacity, and reduced expression of inhibitors of apoptosis proteins also resulted. Cytotoxicity of the drug combination was mitigated by exposure to antioxidant. Cells metabolized C6-ceramide by glycosylation and hydrolysis, the latter leading to increases in long-chain ceramides. Tamoxifen potently blocked glycosylation of C6-ceramide and long-chain ceramides. N-desmethyltamoxifen, a poor antiestrogen and the major tamoxifen metabolite in humans, was also effective with C6-ceramide, indicating that traditional antiestrogen pathways are not involved in cellular responses. We conclude that cell death is driven by mitochondrial targeting and ROS generation and that tamoxifen enhances the ceramide effect by blocking its metabolism. As depletion of ATP and targeting the “Warburg effect” represent dynamic metabolic insult, this ceramide-containing combination may be of utility in the treatment of leukemia and other cancers. PMID:27140664

  17. Source Regions of the Interplanetary Magnetic Field and Variability in Heavy-Ion Elemental Composition in Gradual Solar Energetic Particle Events

    NASA Technical Reports Server (NTRS)

    Ko, Yuan-Kuen; Tylka, Allan J.; Ng, Chee K.; Wang, Yi-Ming; Dietrich, William F.

    2013-01-01

    Gradual solar energetic particle (SEP) events are those in which ions are accelerated to their observed energies by interactions with a shock driven by a fast coronal mass-ejection (CME). Previous studies have shown that much of the observed event-to-event variability can be understood in terms of shock speed and evolution in the shock-normal angle. But an equally important factor, particularly for the elemental composition, is the origin of the suprathermal seed particles upon which the shock acts. To tackle this issue, we (1) use observed solar-wind speed, magnetograms, and the PFSS model to map the Sun-L1 interplanetary magnetic field (IMF) line back to its source region on the Sun at the time of the SEP observations; and (2) then look for correlation between SEP composition (as measured by Wind and ACE at approx. 2-30 MeV/nucleon) and characteristics of the identified IMF-source regions. The study is based on 24 SEP events, identified as a statistically-significant increase in approx. 20 MeV protons and occurring in 1998 and 2003-2006, when the rate of newly-emergent solar magnetic flux and CMEs was lower than in solar-maximum years and the field-line tracing is therefore more likely to be successful. We find that the gradual SEP Fe/O is correlated with the field strength at the IMF-source, with the largest enhancements occurring when the footpoint field is strong, due to the nearby presence of an active region. In these cases, other elemental ratios show a strong charge-to-mass (q/M) ordering, at least on average, similar to that found in impulsive events. These results lead us to suggest that magnetic reconnection in footpoint regions near active regions bias the heavy-ion composition of suprathermal seed ions by processes qualitatively similar to those that produce larger heavy-ion enhancements in impulsive SEP events. To address potential technical concerns about our analysis, we also discuss efforts to exclude impulsive SEP events from our event sample.

  18. High power density targets

    NASA Astrophysics Data System (ADS)

    Pellemoine, Frederique

    2013-12-01

    In the context of new generation rare isotope beam facilities based on high-power heavy-ion accelerators and in-flight separation of the reaction products, the design of the rare isotope production targets is a major challenge. In order to provide high-purity beams for science, high resolution is required in the rare isotope separation. This demands a small beam spot on the production target which, together with the short range of heavy ions in matter, leads to very high power densities inside the target material. This paper gives an overview of the challenges associated with this high power density, discusses radiation damage issues in targets exposed to heavy ion beams, and presents recent developments to meet some of these challenges through different projects: FAIR, RIBF and FRIB which is the most challenging. Extensive use of Finite Element Analysis (FEA) has been made at all facilities to specify critical target parameters and R&D work at FRIB successfully retired two major risks related to high-power density and heavy-ion induced radiation damage.

  19. Role of nuclear volume in driving equilibrium stable isotope fractionation of mercury, thallium, and other very heavy elements

    NASA Astrophysics Data System (ADS)

    Schauble, Edwin A.

    2007-05-01

    Equilibrium stable isotope fractionations of mercury and thallium are estimated for molecules, atoms and ions using first-principles vibrational frequency and electronic structure calculations. These calculations suggest that isotopic variation in nuclear volume is the dominant cause of equilibrium fractionation, driving 205Tl/ 203Tl and 202Hg/ 198Hg fractionations of up to 3‰ at room temperature. Mass-dependent fractionations are smaller, ca. 0.5-1‰ for the same isotopes. Both fractionation mechanisms tend to enrich the neutron-rich isotopes in oxidized mercury- and thallium-bearing phases (Tl 3+ and Hg 2+) relative to reduced phases (Tl + and Hg 0). Among Hg 2+-bearing species, inorganic molecules and complexes like HgCl 2, HgCl42- and Hg(HO)62+ will have higher 202Hg/ 198Hg than coexisting methylmercury species, suggesting a possible application of Hg-isotope measurements to understanding mercury methylation and increasing methylmercury concentrations at the top of the food chain. Estimated 205Tl/ 203Tl fractionation between Tl(HO)63+ and Tl(HO)3+ is in reasonable agreement with the fractionations previously observed between seawater and Fe-Mn crusts, supporting an equilibrium-like reduction/oxidation fractionation mechanism. More generally, nuclear-volume isotope fractionation will concentrate larger (heavier) nuclei in species where the electron density at the nucleus is small—due to lack of s-electrons (e.g., Hg 2+—[Xe]4f 145d 106s 0 vs. Hg 0—[Xe]4f 145d 106s 2) or enhanced s-electron screening by extra p, d, or f electrons (e.g., Tl 0—[Xe]4f 145d 106s 26p 1 vs. Tl +—[Xe]4f 145d 106s 26p 0). Nuclear-volume fractionations become much smaller for lighter elements, declining from ˜1‰/amu for thallium and mercury to ˜0.2‰/amu for ruthenium and ˜0.02‰/amu for sulfur.

  20. Scavenger receptor A gene regulatory elements target gene expression to macrophages and to foam cells of atherosclerotic lesions.

    PubMed Central

    Horvai, A; Palinski, W; Wu, H; Moulton, K S; Kalla, K; Glass, C K

    1995-01-01

    Transcription of the macrophage scavenger receptor A gene is markedly upregulated during monocyte to macrophage differentiation. In these studies, we demonstrate that 291 bp of the proximal scavenger receptor promoter, in concert with a 400-bp upstream enhancer element, is sufficient to direct macrophage-specific expression of a human growth hormone reporter in transgenic mice. These regulatory elements, which contain binding sites for PU.1, AP-1, and cooperating ets-domain transcription factors, are also sufficient to mediate regulation of transgene expression during the in vitro differentiation of bone marrow progenitor cells in response to macrophage colony-stimulating factor. Mutation of the PU.1 binding site within the scavenger receptor promoter severely impairs transgene expression, consistent with a crucial role of PU.1 in regulating the expression of the scavenger receptor gene. The ability of the scavenger receptor promoter and enhancer to target gene expression to macrophages in vivo, including foam cells of atherosclerotic lesions, suggests that these regulatory elements will be of general utility in the study of macrophage differentiation and function by permitting specific modifications of macrophage gene expression. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:7777517

  1. Development of heavy mineral and heavy element database of soil sediments in Japan using synchrotron radiation X-ray powder diffraction and high-energy (116 keV) X-ray fluorescence analysis: 1. Case study of Kofu and Chiba region.

    PubMed

    Bong, Willy Shun Kai; Nakai, Izumi; Furuya, Shunsuke; Suzuki, Hiroko; Abe, Yoshinari; Osaka, Keiichi; Matsumoto, Takuya; Itou, Masayoshi; Imai, Noboru; Ninomiya, Toshio

    2012-07-10

    We have started the construction of a nationwide forensic soil sediment database for Japan based on the heavy mineral and trace heavy element compositions of stream sediments collected at 3024 points all over Japan obtained by high-resolution synchrotron X-ray powder diffraction (SR-XRD) and high-energy synchrotron X-ray fluorescence analysis (HE-SR-XRF). In this study, the performance of both techniques was demonstrated by analyzing soil sediments from two different geological regions, the Kofu and Chiba regions in Kanto province, to construct database that can be applied in the future to provenance analysis of soil evidence from a crime scene. The sediments from the quaternary volcanic lithology of the Chiba region were found to be dominated by heavy minerals of volcanic origin - orthopyroxene, clinopyroxene, and amphibole, and the REEs (rare earth elements) within the region showed similar geochemical behavior. On the other hand, four distinct heavy mineral groups were identified in the sediments of the Kofu region, where there is a great variety of underlying bedrock, and the geochemical behavior of the REEs in the sediments also varied accordingly to their geological origins. As such, our study shows that high-resolution SR-XRD data can provide information on the spatial distribution patterns of heavy minerals in stream sediments, playing an important role in determining their likely geographical origin. Meanwhile, the highly sensitive HE-SR-XRF data allow us to study the geochemical behavior of trace heavy elements, especially the REEs in the sediments, providing additional support to further constrain the likely geographical origin of the sediments determined by heavy minerals.

  2. Grain refinement in heavy rare earth element-free sintered Nd–Fe–B magnets by addition of a small amount of molybdenum

    SciTech Connect

    Kim, Jin Woo; Lee, Won Suk; Byun, Jong Min; Kim, Young Do; Kim, Se Hoon

    2015-05-07

    We employed a modified refractory-metal-addition method to achieve higher coercivity and remanence in heavy rare earth element (HREE)-free Nd–Fe–B sintered magnets. This process involved inducing the formation of a homogeneous secondary phase at the grain boundaries during sintering, making it possible to control the intergrain diffusion by adding small amounts of Mo, a refractory metal. To control the microstructure of the secondary phase effectively, a metal organic compound of the refractory metal was coated on the surfaces of the particles of an HREE-free Nd–Fe–B powder. The average grain size after this process was 5.60 μm, which was approximately 1.8 μm smaller than that of the HREE-free sintered Nd–Fe–B magnets (7.4 μm). The coercivity of the magnets prepared through this process could be increased from 11.88 kOe to 13.91 kOe without decreasing their remanence.

  3. Report on the recent advances performed in the determination of radiative parameters for spectral lines of astrophysical interest in heavy elements

    NASA Astrophysics Data System (ADS)

    Quinet, Pascal

    2015-08-01

    Heavy atoms and ions of the periodic table, in particular those with Z > 36, have been rather little investigated up to until very recently, due to the numerous difficulties met both on the theoretical and on the experimental sides. In relation with the recent needs in astrophysics, the situtaion has considerably evolved over the past few years and substantial progress has been reported. This progress has been made easier by the developments of theoretical methods and also by the extensive use of laser spectroscopy.Having in mind the astrophysical context, we have started a systematic investigation of radiative parameters of these ions (neutral, singly and doubly ionized elements) about 15 years ago. As a consequence, a large number of new results have been obtained. About 700 radiative lifetimes have been measured by time-resolved laser-induced fluorescence spectroscopy. The combination of these lifetimes with theoretical (and, when possible, experimental) branching fractions has led to transition probabilities for about 100000 transitions in atoms and ions belonging to the lanthanide group as well as to the fifth and the sixth rows of the periodic table.

  4. lumpGEM: Systematic generation of subnetworks and elementally balanced lumped reactions for the biosynthesis of target metabolites

    PubMed Central

    Ataman, Meric

    2017-01-01

    In the post-genomic era, Genome-scale metabolic networks (GEMs) have emerged as invaluable tools to understand metabolic capabilities of organisms. Different parts of these metabolic networks are defined as subsystems/pathways, which are sets of functional roles to implement a specific biological process or structural complex, such as glycolysis and TCA cycle. Subsystem/pathway definition is also employed to delineate the biosynthetic routes that produce biomass building blocks. In databases, such as MetaCyc and SEED, these representations are composed of linear routes from precursors to target biomass building blocks. However, this approach cannot capture the nested, complex nature of GEMs. Here we implemented an algorithm, lumpGEM, which generates biosynthetic subnetworks composed of reactions that can synthesize a target metabolite from a set of defined core precursor metabolites. lumpGEM captures balanced subnetworks, which account for the fate of all metabolites along the synthesis routes, thus encapsulating reactions from various subsystems/pathways to balance these metabolites in the metabolic network. Moreover, lumpGEM collapses these subnetworks into elementally balanced lumped reactions that specify the cost of all precursor metabolites and cofactors. It also generates alternative subnetworks and lumped reactions for the same metabolite, accounting for the flexibility of organisms. lumpGEM is applicable to any GEM and any target metabolite defined in the network. Lumped reactions generated by lumpGEM can be also used to generate properly balanced reduced core metabolic models. PMID:28727789

  5. Key Elements of and Materials Performance Targets for Highly Insulating Window Frames

    SciTech Connect

    Gustavsen, Arild; Grynning, Steinar; Arasteh, Dariush; Jelle, Bjorn Petter; Goudey, Howdy

    2011-03-28

    The thermal performance of windows is important for energy efficient buildings. Windows typically account for about 30-50 percent of the transmission losses though the building envelope, even if their area fraction of the envelope is far less. The reason for this can be found by comparing the thermal transmittance (U-factor) of windows to the U-factor of their opaque counterparts (wall, roof and floor constructions). In well insulated buildings the U-factor of walls, roofs an floors can be between 0.1-0.2 W/(m2K). The best windows have U-values of about 0.7-1.0. It is therefore obvious that the U-factor of windows needs to be reduced, even though looking at the whole energy balance for windows (i.e. solar gains minus transmission losses) makes the picture more complex.In high performance windows the frame design and material use is of utmost importance, as the frame performance is usually the limiting factor for reducing the total window U-factor further. This paper describes simulation studies analyzing the effects on frame and edge-of-glass U-factors of different surface emissivities as well as frame material and spacer conductivities. The goal of this work is to define materials research targets for window frame components that will result in better frame thermal performance than is exhibited by the best products available on the market today.

  6. Top Quark Produced Through the Electroweak Force: Discovery Using the Matrix Element Analysis and Search for Heavy Gauge Bosons Using Boosted Decision Trees

    SciTech Connect

    Pangilinan, Monica

    2010-05-01

    The top quark produced through the electroweak channel provides a direct measurement of the Vtb element in the CKM matrix which can be viewed as a transition rate of a top quark to a bottom quark. This production channel of top quark is also sensitive to different theories beyond the Standard Model such as heavy charged gauged bosons termed W'. This thesis measures the cross section of the electroweak produced top quark using a technique based on using the matrix elements of the processes under consideration. The technique is applied to 2.3 fb-1 of data from the D0 detector. From a comparison of the matrix element discriminants between data and the signal and background model using Bayesian statistics, we measure the cross section of the top quark produced through the electroweak mechanism σ(p$\\bar{p}$ → tb + X, tqb + X) = 4.30-1.20+0.98 pb. The measured result corresponds to a 4.9σ Gaussian-equivalent significance. By combining this analysis with other analyses based on the Bayesian Neural Network (BNN) and Boosted Decision Tree (BDT) method, the measured cross section is 3.94 ± 0.88 pb with a significance of 5.0σ, resulting in the discovery of electroweak produced top quarks. Using this measured cross section and constraining |Vtb| < 1, the 95% confidence level (C.L.) lower limit is |Vtb| > 0.78. Additionally, a search is made for the production of W' using the same samples from the electroweak produced top quark. An analysis based on the BDT method is used to separate the signal from expected backgrounds. No significant excess is found and 95% C.L. upper limits on the production cross section are set for W' with masses within 600-950 GeV. For four general models of W{prime} boson production using decay channel W' → t$\\bar{p}$, the lower mass limits are the following: M(W'L with SM couplings) > 840 GeV; M(W'R) > 880 GeV or 890 GeV if the right-handed neutrino is

  7. Top quark produced through the electroweak force: Discovery using the matrix element analysis and search for heavy gauge bosons using boosted decision trees

    NASA Astrophysics Data System (ADS)

    Pangilinan, Monica

    The top quark produced through the electroweak channel provides a direct measurement of the Vtb element in the CKM matrix which can be viewed as a transition rate of a top quark to a bottom quark. This production channel of top quark is also sensitive to different theories beyond the Standard Model such as heavy charged gauged bosons termed W'. This thesis measures the cross section of the electroweak produced top quark using a technique based on using the matrix elements of the processes under consideration. The technique is applied to 2.3 fb--1 of data from the DO detector. From a comparison of the matrix element discriminants between data and the signal and background model using Bayesian statistics, we measure the cross section of the top quark produced through the electroweak mechanism spp¯→ tb+X,tqb+X=4.30+0.98-1.2 0pb The measured result corresponds to a 4.9sigma Gaussian-equivalent significance. By combining this analysis with other analyses based on the Bayesian Neural Network (BNN) and Boosted Decision Tree (BDT) method, the measured cross section is 3.94 +/- 0.88 pb with a significance of 5.0sigma, resulting in the discovery of electroweak produced top quarks. Using this measured cross section and constraining |Vtb| < 1, the 95% confidence level (C.L.) lower limit is |Vtb| > 0.78. Additionally, a search is made for the production of W' using the same samples from the electroweak produced top quark. An analysis based on the BDT method is used to separate the signal from expected backgrounds. No significant excess is found and 95% C.L. upper limits on the production cross section are set for W' with masses within 600--950 GeV. For four general models of W' boson production using decay channel W' → tb¯, the lower mass limits are the following: M( W'L with SM couplings) > 840 GeV; M( W'R ) > 880 GeV or 890 GeV if the right-handed neutrino is lighter or heavier than W'R ; and M( W'L+R ) > 915 GeV.

  8. Multi-unit inertial fusion plants based on HYLIFE-II, with shared heavy-ion RIA driver and target factory, producing electricity and hydrogen fuel

    SciTech Connect

    Logan, G.; Moir, R.; Hoffman, M.

    1994-05-05

    Following is a modification of the IFEFUEL systems code, called IFEFUEL2, to treat specifically the HYLIFE-II target chamber concept. The same improved Recirculating Induction Accelerator (RIA) energy scaling model developed recently by Bieri is used in this survey of the economics of multi-unit IFE plants producing both electricity and hydrogen fuel. Reference cases will assume conventional HI-indirect target gains for a 2 mm spot, and improved HYLIFE-II BoP models as per Hoffman. Credits for improved plant availability and lower operating costs due to HYLIFE-II`s 30-yr target chamber lifetime are included, as well as unit cost reductions suggested by Delene to credit greater {open_quotes}learning curve{close_quotes} benefits for the duplicated portions of a multi-unit plant. To illustrate the potential impact of more advanced assumptions, additional {open_quotes}advanced{close_quotes} cases will consider the possible benefits of an MHD + Steam BoP, where direct MHD conversion of plasma from baseball-size LiH target blanket shells is assumed to be possible in a new (as yet undesigned) liquid Flibe-walled target chamber, together and separately, with advanced, higher-gain heavy-ion targets with Fast Ignitors. These runs may help decide the course of a possible future {open_quotes}HYLIFE-III{close_quotes} IFE study. Beam switchyard and final focusing system costs per target chamber are assumed to be consistent with single-sided illumination, for either {open_quotes}conventional{close_quotes} or {open_quotes}advanced{close_quotes} indirect target gain assumptions. Target costs are scaled according to the model by Woodworth. In all cases, the driver energy and rep rate for each chosen number of target chambers and total plant output will be optimized to minimize the cost of electricity (CoE) and the associated cost of hydrogen (CoH), using a relationship between CoE and CoH to be presented in the next section.

  9. Ion-driver fast ignition: Reducing heavy-ion fusion driver energy and cost, simplifying chamber design, target fab, tritium fueling and power conversion

    SciTech Connect

    Logan, G.; Callahan-Miller, D.; Perkins, J.; Caporaso, G.; Tabak, M.; Moir, R.; Meier, W.; Bangerter, Roger; Lee, Ed

    1998-04-01

    (built-in as part of each target); (4) beam space charge-neutralization during both drift compression and final focus to target. Except for (1) and (2), these critical issues may be explored on existing heavy-ion storage ring accelerator facilities.

  10. Distributing Characteristics of Heavy Metal Elements in A Tributary of Zhedong River in Laowangzhai Gold Deposit, Yunnan (China): An Implication to Environmentology from Sediments

    NASA Astrophysics Data System (ADS)

    Yang, Shuran; Danĕk, Tomáš; Yang, Xiaofeng; Cheng, Xianfeng

    2016-10-01

    Five heavy metal contents from five sediments and seven sediment profiles in an upstream reach of Zhedong river in Laowangzhai gold deposit were investigated in this research, along with analysis of the horizontal distribution, the surface distribution, the vertical distribution and the interlayer distribution of five heavy metal contents: arsenic (As), mercury (Hg), copper (Cu), lead (Pb) and zinc (Zn). The potential ecological risk of five heavy metals was evaluated to help understanding pollution control of Laowangzhai deposit.

  11. Binary-encounter electron emission after fast heavy-ion impact on complex rare- and molecular-gas targets

    NASA Astrophysics Data System (ADS)

    Bechthold, U.; Ullrich, J.; Ramm, U.; Kraft, G.; Hagmann, S.; Schultz, D. R.; Reinhold, C. O.; Schmidt-Böcking, H.

    1998-09-01

    Doubly differential cross sections (DDCSs) for electron emission have been measured for collisions of 3.6 MeV/u Ne10+, Xe40+ and 5.9 MeV/u U29+ on neon, xenon, water, ethanol, methanol, propanol, C2F6, SF6, and C3F8. Electrons ejected with emission angles between 0° and 180° with respect to the ion beam axis have been recorded simultaneously using a toroidal electron spectrometer. We analyze the singly differential cross section (SDCS) for binary encounter electron (BEe) production as a function of target electron number and laboratory emission angle. We find that there exists a linear scaling of the BEe SDCS with the number of electrons bound in the target with an energy lower than the reduced projectile energy. The enhancement of BEe production in the forward direction in collisions with partially stripped ions is studied for the different projectiles and targets and compared to theoretical calculations.

  12. Targeted identification of short interspersed nuclear element families shows their widespread existence and extreme heterogeneity in plant genomes.

    PubMed

    Wenke, Torsten; Döbel, Thomas; Sörensen, Thomas Rosleff; Junghans, Holger; Weisshaar, Bernd; Schmidt, Thomas

    2011-09-01

    Short interspersed nuclear elements (SINEs) are non-long terminal repeat retrotransposons that are highly abundant, heterogeneous, and mostly not annotated in eukaryotic genomes. We developed a tool designated SINE-Finder for the targeted discovery of tRNA-derived SINEs. We analyzed sequence data of 16 plant genomes, including 13 angiosperms and three gymnosperms and identified 17,829 full-length and truncated SINEs falling into 31 families showing the widespread occurrence of SINEs in higher plants. The investigation focused on potato (Solanum tuberosum), resulting in the detection of seven different SolS SINE families consisting of 1489 full-length and 870 5' truncated copies. Consensus sequences of full-length members range in size from 106 to 244 bp depending on the SINE family. SolS SINEs populated related species and evolved separately, which led to some distinct subfamilies. Solanaceae SINEs are dispersed along chromosomes and distributed without clustering but with preferred integration into short A-rich motifs. They emerged more than 23 million years ago and were species specifically amplified during the radiation of potato, tomato (Solanum lycopersicum), and tobacco (Nicotiana tabacum). We show that tobacco TS retrotransposons are composite SINEs consisting of the 3' end of a long interspersed nuclear element integrated downstream of a nonhomologous SINE family followed by successfully colonization of the genome. We propose an evolutionary scenario for the formation of TS as a spontaneous event, which could be typical for the emergence of SINE families.

  13. Targeted Identification of Short Interspersed Nuclear Element Families Shows Their Widespread Existence and Extreme Heterogeneity in Plant Genomes[W

    PubMed Central

    Wenke, Torsten; Döbel, Thomas; Sörensen, Thomas Rosleff; Junghans, Holger; Weisshaar, Bernd; Schmidt, Thomas

    2011-01-01

    Short interspersed nuclear elements (SINEs) are non-long terminal repeat retrotransposons that are highly abundant, heterogeneous, and mostly not annotated in eukaryotic genomes. We developed a tool designated SINE-Finder for the targeted discovery of tRNA-derived SINEs. We analyzed sequence data of 16 plant genomes, including 13 angiosperms and three gymnosperms and identified 17,829 full-length and truncated SINEs falling into 31 families showing the widespread occurrence of SINEs in higher plants. The investigation focused on potato (Solanum tuberosum), resulting in the detection of seven different SolS SINE families consisting of 1489 full-length and 870 5′ truncated copies. Consensus sequences of full-length members range in size from 106 to 244 bp depending on the SINE family. SolS SINEs populated related species and evolved separately, which led to some distinct subfamilies. Solanaceae SINEs are dispersed along chromosomes and distributed without clustering but with preferred integration into short A-rich motifs. They emerged more than 23 million years ago and were species specifically amplified during the radiation of potato, tomato (Solanum lycopersicum), and tobacco (Nicotiana tabacum). We show that tobacco TS retrotransposons are composite SINEs consisting of the 3′ end of a long interspersed nuclear element integrated downstream of a nonhomologous SINE family followed by successfully colonization of the genome. We propose an evolutionary scenario for the formation of TS as a spontaneous event, which could be typical for the emergence of SINE families. PMID:21908723

  14. A novel target-specific gene delivery system combining baculovirus and sequence-specific long interspersed nuclear elements.

    PubMed

    Kawashima, Tomoko; Osanai, Mizuko; Futahashi, Ryo; Kojima, Tetsuya; Fujiwara, Haruhiko

    2007-07-01

    Transposable elements are valuable for somatic and germ-line transformation. However, long interspersed nuclear elements (LINEs) have not been used because of poor information on the transposition mechanism. We have developed a novel gene delivery system combining baculovirus AcNPV and two silkworm LINEs, SART1 and R1, which integrate into specific sequences of telomeric repeats and 28S ribosomal DNA, respectively. When two LINEs containing the enhanced green fluorescent protein gene recombined into AcNPV were infected into fifth instar larvae of the silkworm, we observed target-specific retrotransposition of LINEs at 72h post-infection, using polymerase chain reaction amplification and sequencing. Telomere- and 28S rDNA-specific transposition occurred in all nine tissues tested, including the ovary and testis. This is the first demonstration of site-specific gene delivery in living larvae. Insertion efficiencies were dependent on the virus titer for injection and the host strains of Bombyx mori. Using this system, we successfully detected the intergeneration transmission of retrotransposed sequences. In addition, AcNPV-mediated SART1 also transposed into telomere of another lepidopteran, Orgyia recens, suggesting that this system is useful for a wide variety of AcNPV-infectious insects. Site-specific gene delivery by virus-mediated LINE will be a potential gene therapy tool to avoid harmful unexpected insertions.

  15. A cross sectional study of hepatitis B, C, some trace elements, heavy metals, aflatoxin B1 and schistosomiasis in a rural population, Egypt.

    PubMed

    Sayed, Hanan Ali; El Ayyat, Afaf; El Dusoki, Howaida; Zoheiry, Mona; Mohamed, Salwa; Hassan, Mona; El Assaly, Nihal; Awad, Alaa; El Ansary, Mahmoud; Saad, Amal; El Karim, Ahmed Abd

    2005-01-01

    Chronic liver diseases are disastrous to health. Many factors are associated with their prevalence, hence endemicity. These are mainly infectious, parasitic and toxic. A survey was conducted in a village south to Cairo. Large industries concerned with iron and steel industry, metals smelting, cement manufacturing and electric station were located north to the village. A systematic random sample of houses was selected. All individuals inside the houses were invited to share in the study. Sample size was 84 individuals. Hepatitis markers were done (HBsAg and anti-HCV antibodies). The levels of some heavy metals were assessed; which were lead, mercury, arsenic, aluminum, manganese, nickel, chromium and cadmium. Levels of some trace elements were assessed. These were copper, iron, selenium and zinc. Aflatoxin B1 was assessed in serum. Assessment of schistosomal circulating antigen and antibodies was carried out. Abdominal ultrasonograghy was done to assess liver condition. Univariate logistic regression analysis was done to assess the association between studied variables and HBsAg or anti-HCV sero-positive subjects. The association between studied variables and bilharzial or fatty liver, diagnosed by ultrasonography, were also assessed. The univariate logistic regression analysis revealed odds ratios at the following results. For HBsAg seropositive subjects, aflatoxin B1, lead, chromium and schistosomal antigen and antibodies were higher than negative ones where odds ratios were; 6.2, 1.6, 1.6, 1.6 and 1.7, respectively. None of the variables showed statistically significant difference. For anti-HCV antibodies sero-positive subjects, aflatoxin B1 and chromium had the highest odds ratios among the studied variables, (odds ratios were 2.5 and 2.4, respectively). Bilharzial liver showed higher significant positivity of anti-HCV antibodies and insignificant decreased level of zinc than negative ones (odds ratios were 7.2 and 4.5, respectively). Fatty liver cases showed

  16. EFFECT OF LASER LIGHT ON MATTER. LASER PLASMAS: Films containing heavy hydrogen isotopes in laser thermonuclear fusion targets

    NASA Astrophysics Data System (ADS)

    Abramov, Yu A.; Bessarab, A. V.; Veselov, A. V.; Gavrilov, P. I.; Druzhinin, A. A.; Izgorodin, V. M.; Karel'skaya, T. V.; Kirillov, G. A.; Komleva, G. V.; Lyamin, G. A.; Nikolaev, G. P.; Pinegin, A. V.; Punin, V. T.; Rabinovich, K. G.; Romaev, V. N.; Rogachev, V. G.; Solomatina, E. Yu; Tarasova, N. N.; Tachaev, G. V.; Andryushin, V. V.; Emel'yanov, S. A.; Kryuchenkov, V. B.; Markelov, N. N.; Markushkin, Yu E.; Chirin, N. A.

    1994-02-01

    An investigation was made of fuel films in targets used in experiments on laser thermonuclear fusion in Iskra-4 and Iskra-5 systems. These films were formed from condensed deuterium and a deuterium—tritium mixture, and also from metal hydrides and polyethylene containing deuterium and tritium.

  17. The role of repair in the survival of mammalian cells from heavy ion irradiation - Approximation to the ideal case of target theory

    NASA Technical Reports Server (NTRS)

    Lett, J. T.; Cox, A. B.; Story, M. D.

    1989-01-01

    Experiments are discussed in which the cell-cycle dependency of the repair deficiency of the S/S variant of the L5178Y murine leukemic lymphoblast was examined by treatment with the heavy ions, Ne-20, Si-28, Ar-40, Fe-56, and Nb-93. Evidence from those studies provide support for the notion that as the linear energy transfer of the incident radiation increases the ability of the S/S cell to repair radiation damage decreases until it is eliminated around 500 keV/micron. In the region of the latter linear energy transfer value, the behavior of the S/S cell approximates the ideal case of target theory where post-irradiation metabolism does not influence cell survival.

  18. The role of repair in the survival of mammalian cells from heavy ion irradiation - Approximation to the ideal case of target theory

    NASA Technical Reports Server (NTRS)

    Lett, J. T.; Cox, A. B.; Story, M. D.

    1989-01-01

    Experiments are discussed in which the cell-cycle dependency of the repair deficiency of the S/S variant of the L5178Y murine leukemic lymphoblast was examined by treatment with the heavy ions, Ne-20, Si-28, Ar-40, Fe-56, and Nb-93. Evidence from those studies provide support for the notion that as the linear energy transfer of the incident radiation increases the ability of the S/S cell to repair radiation damage decreases until it is eliminated around 500 keV/micron. In the region of the latter linear energy transfer value, the behavior of the S/S cell approximates the ideal case of target theory where post-irradiation metabolism does not influence cell survival.

  19. Heavy Element Spectroscopy At JYFL

    SciTech Connect

    Greenlees, P.T.; Eeckhaudt, S.; Grahn, T.; Jones, P.; Julin, R.; Juutinen, S.; Kankaanpaeae, H.; Keenan, A.; Kettunen, H.; Leino, M.; Leppaenen, A.-P.; Muikku, M.; Nieminen, P.; Pakarinen, J.; Rahkila, P.; Scholey, C.; Uusitalo, J.; Amzal, N.; Bastin, J.E.; Hammond, N.J.

    2005-04-05

    A series of experiments to study the properties of transfermium nuclei have been performed at the Department of Physics of the University of Jyvaeskylae. The experiments are carried out by a large group of collaborating institutes. These studies have been rendered possible by the coupling of various state-of-the-art detector systems to the RITU gas-filled recoil separator. In-beam conversion-electron and gamma-ray measurements have been made using the SACRED silicon and JuroGam germanium-detector arrays, respectively. The introduction of the GREAT spectrometer and TDR data acquisition system have greatly improved the quality of the data obtained at RITU. A brief overview of the instrumentation used and highlights from recent experiments are presented.

  20. Spectroscopy of very heavy elements

    SciTech Connect

    Julin, Rauno

    2004-02-27

    Data from in-beam spectroscopic experiments using recoil gating and recoil-decay-tagging (RDT) techniques carried out at the Jyvaeskylae Accelerator Laboratory (JYFL) for 254No, 252No, 250Fm and255Lr are presented and discussed.

  1. Increasing prevalence of ciprofloxacin-resistant food-borne Salmonella strains harboring multiple PMQR elements but not target gene mutations

    PubMed Central

    Lin, Dachuan; Chen, Kaichao; Wai-Chi Chan, Edward; Chen, Sheng

    2015-01-01

    Fluoroquinolone resistance in Salmonella has become increasingly prevalent in recent years. To probe the molecular basis of this phenomenon, the genetic and phenotypic features of fluoroquinolone resistant Salmonella strains isolated from food samples were characterized. Among the 82 Salmonella strains tested, resistance rate of the three front line antibiotics of ceftriaxone, ciprofloxacin and azithromycin was 10%, 39% and 25% respectively, which is significantly higher than that reported in other countries. Ciprofloxacin resistant strains typically exhibited cross-resistance to multiple antibiotics including ceftriaxone, primarily due to the presence of multiple PMQR genes and the blaCTX-M-65, blaCTX-M-55 blaCMY-2 and blaCMY-72 elements. The prevalence rate of the oqxAB and aac(6’)-Ib-cr genes were 91% and 75% respectively, followed by qnrS (66%), qnrB (16%) and qnrD (3%). The most common PMQR combination observable was aac(6’)-Ib-cr-oqxAB-qnrS2, which accounted for 50% of the ciprofloxacin resistant strains. Interestingly, such isolates contained either no target mutations or only a single gyrA mutation. Conjugation and hybridization experiments suggested that most PMQR genes were located either in the chromosome or a non-transferrable plasmid. To summarize, findings in this work suggested that PMQRs greatly facilitate development of fluoroquinolone resistance in Salmonella by abolishing the requirement of target gene mutations. PMID:26435519

  2. Development of an odd-Z-projectile reaction for heavy element synthesis: 208Pb(64Ni, n)271Ds and 208Pb(65Cu, n)272111

    SciTech Connect

    Folden III, C.M.; Gregorich, K.E.; Dullmann, Ch.E.; Mahmud, H.; Pang, G.K.; Schwantes, J.M.; Sudowe, R.; Zielinski, P.M.; Nitsche, H.; Hoffman, D.C.

    2004-08-16

    Seven {sup 271}Ds decay chains were identified in the bombardment of {sup 208}Pb targets with 311.5- and 314.3-MeV {sup 64}Ni projectiles using the Berkeley Gas-filled Separator. These data, combined with previous results, provide an excitation function for this reaction. From these results, an optimum energy of 321 MeV was estimated for the production of {sup 272}111 in the reaction {sup 208}Pb({sup 65}Cu, n). One decay chain was observed, resulting in a cross section of 1.7{sub -1.4}{sup +3.9} pb. This experiment confirms the discovery of element 111 by the Darmstadt group who used the {sup 209}Bi({sup 64}Ni, n){sup 272}111 reaction.

  3. The F-box family genes as key elements in response to salt, heavy mental, and drought stresses in Medicago truncatula.

    PubMed

    Song, Jian Bo; Wang, Yan Xiang; Li, Hai Bo; Li, Bo Wen; Zhou, Zhao Sheng; Gao, Shuai; Yang, Zhi Min

    2015-07-01

    F-box protein is a subunit of Skp1-Rbx1-Cul1-F-box protein (SCF) complex with typically conserved F-box motifs of approximately 40 amino acids and is one of the largest protein families in eukaryotes. F-box proteins play critical roles in selective and specific protein degradation through the 26S proteasome. In this study, we bioinformatically identified 972 putative F-box proteins from Medicago truncatula genome. Our analysis showed that in addition to the conserved motif, the F-box proteins have several other functional domains in their C-terminal regions (e.g., LRRs, Kelch, FBA, and PP2), some of which were found to be M. truncatula species-specific. By phylogenetic analysis of the F-box motifs, these proteins can be classified into three major families, and each family can be further grouped into more subgroups. Analysis of the genomic distribution of F-box genes on M. truncatula chromosomes revealed that the evolutional expansion of F-box genes in M. truncatula was probably due to localized gene duplications. To investigate the possible response of the F-box genes to abiotic stresses, both publicly available and customer-prepared microarrays were analyzed. Most of the F-box protein genes can be responding to salt and heavy metal stresses. Real-time PCR analysis confirmed that some of the F-box protein genes containing heat, drought, salicylic acid, and abscisic acid responsive cis-elements were able to respond to the abiotic stresses.

  4. Binary-encounter electron emission after fast heavy-ion impact on complex rare- and molecular-gas targets

    SciTech Connect

    Bechthold, U.; Ullrich, J.; Ramm, U.; Kraft, G.; Hagmann, S.; Schultz, D.R.; Reinhold, C.O.; Schmidt-Boecking, H.

    1998-09-01

    Doubly differential cross sections (DDCSs) for electron emission have been measured for collisions of 3.6 MeV/u Ne{sup 10+}, Xe{sup 40+} and 5.9 MeV/u U{sup 29+} on neon, xenon, water, ethanol, methanol, propanol, C{sub 2}F{sub 6}, SF{sub 6}, and C{sub 3}F{sub 8}. Electrons ejected with emission angles between 0{degree} and 180{degree} with respect to the ion beam axis have been recorded simultaneously using a toroidal electron spectrometer. We analyze the singly differential cross section (SDCS) for binary encounter electron (BE{ital e}) production as a function of target electron number and laboratory emission angle. We find that there exists a linear scaling of the BE{ital e} SDCS with the number of electrons bound in the target with an energy lower than the reduced projectile energy. The enhancement of BE{ital e} production in the forward direction in collisions with partially stripped ions is studied for the different projectiles and targets and compared to theoretical calculations. {copyright} {ital 1998} {ital The American Physical Society}

  5. Quasispherical fuel compression and fast ignition in a heavy-ion-driven X-target with one-sided illumination

    SciTech Connect

    Henestroza, Enrique; Logan, B. Grant; Perkins, L. John

    2011-03-15

    The HYDRA radiation-hydrodynamics code [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] is used to explore one-sided axial target illumination with annular and solid-profile uranium ion beams at 60 GeV to compress and ignite deuterium-tritium fuel filling the volume of metal cases with cross sections in the shape of an ''X'' (X-target). Quasi-three-dimensional, spherical fuel compression of the fuel toward the X-vertex on axis is obtained by controlling the geometry of the case, the timing, power, and radii of three annuli of ion beams for compression, and the hydroeffects of those beams heating the case as well as the fuel. Scaling projections suggest that this target may be capable of assembling large fuel masses resulting in high fusion yields at modest drive energies. Initial two-dimensional calculations have achieved fuel compression ratios of up to 150X solid density, with an areal density {rho}R of about 1 g/cm{sup 2}. At these currently modest fuel densities, fast ignition pulses of 3 MJ, 60 GeV, 50 ps, and radius of 300 {mu}m are injected through a hole in the X-case on axis to further heat the fuel to propagating burn conditions. The resulting burn waves are observed to propagate throughout the tamped fuel mass, with fusion yields of about 300 MJ. Tamping is found to be important, but radiation drive to be unimportant, to the fuel compression. Rayleigh-Taylor instability mix is found to have a minor impact on ignition and subsequent fuel burn-up.

  6. MiR-199a-5p suppresses tumorigenesis by targeting clathrin heavy chain in hepatocellular carcinoma.

    PubMed

    Huang, Guo-Hao; Shan, Hong; Li, Dan; Zhou, Bin; Pang, Peng-Fei

    2017-03-01

    The deregulation of microRNA (miRNA) is frequently associated with a variety of cancers, including hepatocellular carcinoma (HCC). In this study, we investigated the expression and possible role of miR-199a-5p in HCC. The expression of miR-199a-5p was measured by quantitative RT-PCR in HCC. The effect of miR-199a-5p was evaluated by cell viability and colony formation assays in HCC cell lines and tumor cell growth assay in xenograft nude mice. Quantitative real time PCR results showed that miR-199a-5p was down-regulated in 77.9 % (67/86) of HCC tissues compared with adjacent nontumor tissues. MiR-199a-5p mimic reduced cell viability and colony formation by induction of cell arrest in HCC cell lines and inhibited tumor cell growth in xenograft nude mice, but miR-199a-5p inhibitor increased cell viability and colony formation in HCC cell lines and tumor cell growth in xenograft nude mice. Furthermore, CLTC was defined as a potential direct target of miR-199a-5p by MiRanda and TargetScan predictions. The dual-luciferase reporter gene assay results showed that CLTC was a direct target of miR-199a-5p. The use of miR-199a-5p mimic or inhibitor could decrease or increase CLTC protein levels in HCC cell lines. We conclude that the frequently down-regulated miR-199a-5p can regulate CLTC and might function as a tumor suppressor in HCC. Therefore, miR-199a-5p may serve as a useful therapeutic agent for miRNA-based HCC therapy.

  7. Heat transfer to a heavy liquid metal in curved geometry: Code validation and CFD simulation for the MEGAPIE lower target

    NASA Astrophysics Data System (ADS)

    Dury, Trevor V.

    2006-06-01

    The ESS and SINQ Heat Emitting Temperature Sensing Surface (HETSS) mercury experiments have been used to validate the Computational Fluid Dynamics (CFD) code CFX-4 employed in designing the lower region of the international liquid metal cooled MEGAPIE target, to be installed at SINQ, PSI, in 2006. Conclusions were drawn on the best turbulence models and degrees of mesh refinement to apply, and a new CFD model of the MEGAPIE geometry was made, based on the CATIA CAD design of the exact geometry constructed. This model contained the fill and drain tubes as well as the bypass feed duct, with the differences in relative vertical length due to thermal expansion being considered between these tubes and the window. Results of the mercury experiments showed that CFD calculations can be trusted to give peak target window temperature under normal operational conditions to within about ±10%. The target nozzle actually constructed varied from the theoretical design model used for CFD due to the need to apply more generous separation distances between the nozzle and the window. In addition, the bypass duct contraction approaching the nozzle exit was less sharp compared with earlier designs. Both of these changes modified the bypass jet penetration and coverage of the heated window zone. Peak external window temperature with a 1.4 mA proton beam and steady-state operation is now predicted to be 375 °C, with internal temperature 354.0 °C (about 32 °C above earlier predictions). Increasing bypass flow from 2.5 to 3.0 kg/s lowers these peak temperatures by about 12 °C. Stress analysis still needs to be made, based on these thermal data.

  8. Myosin‑II heavy chain and formin mediate the targeting of myosin essential light chain to the division site before and during cytokinesis

    PubMed Central

    Feng, Zhonghui; Okada, Satoshi; Cai, Guoping; Zhou, Bing; Bi, Erfei

    2015-01-01

    MLC1 is a haploinsufficient gene encoding the essential light chain for Myo1, the sole myosin‑II heavy chain in the budding yeast Saccharomyces cerevisiae. Mlc1 defines an essential hub that coordinates actomyosin ring function, membrane trafficking, and septum formation during cytokinesis by binding to IQGAP, myosin‑II, and myosin‑V. However, the mechanism of how Mlc1 is targeted to the division site during the cell cycle remains unsolved. By constructing a GFP‑tagged MLC1 under its own promoter control and using quantitative live‑cell imaging coupled with yeast mutants, we found that septin ring and actin filaments mediate the targeting of Mlc1 to the division site before and during cytokinesis, respectively. Both mechanisms contribute to and are collectively required for the accumulation of Mlc1 at the division site during cytokinesis. We also found that Myo1 plays a major role in the septin‑dependent Mlc1 localization before cytokinesis, whereas the formin Bni1 plays a major role in the actin filament–dependent Mlc1 localization during cytokinesis. Such a two‑tiered mechanism for Mlc1 localization is presumably required for the ordered assembly and robustness of cytokinesis machinery and is likely conserved across species. PMID:25631819

  9. An estrogen-responsive element-targeted histone deacetylase enzyme has an antiestrogen activity that differs from that of hydroxytamoxifen.

    PubMed

    Demirpence, Ediz; Semlali, Abdelhabib; Oliva, Joan; Balaguer, Patrick; Badia, Eric; Duchesne, Marie-Josèphe; Nicolas, Jean-Claude; Pons, Michel

    2002-11-15

    We showed previously that prolonged treatment of a MCF-7-derived cell line with hydroxytamoxifen (OHT) induces the irreversible silencing of some estrogen-responsive genes, whereas OHT-resistant cell growth appears simultaneously (E. Badia et al., Cancer Res., 60: 4130-4138, 2000). Based on the hypothesis that particular gene silencings could be involved in triggering the resistance phenomenon, we focused our study on the mechanism of OHT-induced silencing. More precisely, we wished to determine to what extent the recruited histone deacetylase (HDAC) activity, which is known to be involved in the repressive effect induced by antagonist ligands of nuclear receptors, could participate in various aspects of OHT effects, particularly in gene silencing. A fusion protein (HDAC-EG) of human HDAC1 fused with the estrogen receptor DNA-binding domain and the glucocorticoid receptor ligand-binding domain allowed targeting of chimeric HDAC1 activity on estrogen-responsive elements (EREs) in the presence of glucocorticoid ligands. When HDAC-EG was transiently expressed in HeLa cells together with estrogen receptor, an antiestrogen-like effect was obtained on an ERE-controlled luciferase reporter gene in the presence of agonist or antagonist glucocorticoids. In MCF-7-derived cells stably expressing HDAC-EG and an estrogen-regulated luciferase, liganded HDAC-EG again produced an antiestrogenic effect on expression of natural estrogen-regulated genes such as pS2, progesterone receptor, and cathepsin D and cell growth together with chimeric luciferase gene expression. However, a prolonged HDAC-EG-mediated antiestrogen effect did not lead to irreversible luciferase gene silencing, as OHT does. It nevertheless accelerated the OHT-driven phenomenon. The antiestrogen effect of OHT thus differs from that of an ERE-targeted HDAC1 activity that might participate in irreversible silencing but is not sufficient to trigger it.

  10. Autism genes are selectively targeted by environmental pollutants including pesticides, heavy metals, bisphenol A, phthalates and many others in food, cosmetics or household products.

    PubMed

    Carter, C J; Blizard, R A

    2016-10-27

    The increasing incidence of autism suggests a major environmental influence. Epidemiology has implicated many candidates and genetics many susceptibility genes. Gene/environment interactions in autism were analysed using 206 autism susceptibility genes (ASG's) from the Autworks database to interrogate ∼1 million chemical/gene interactions in the comparative toxicogenomics database. Any bias towards ASG's was statistically determined for each chemical. Many suspect compounds identified in epidemiology, including tetrachlorodibenzodioxin, pesticides, particulate matter, benzo(a)pyrene, heavy metals, valproate, acetaminophen, SSRI's, cocaine, bisphenol A, phthalates, polyhalogenated biphenyls, flame retardants, diesel constituents, terbutaline and oxytocin, inter alia showed a significant degree of bias towards ASG's, as did relevant endogenous agents (retinoids, sex steroids, thyroxine, melatonin, folate, dopamine, serotonin). Numerous other suspected endocrine disruptors (over 100) selectively targeted ASG's including paraquat, atrazine and other pesticides not yet studied in autism and many compounds used in food, cosmetics or household products, including tretinoin, soy phytoestrogens, aspartame, titanium dioxide and sodium fluoride. Autism polymorphisms influence the sensitivity to some of these chemicals and these same genes play an important role in barrier function and control of respiratory cilia sweeping particulate matter from the airways. Pesticides, heavy metals and pollutants also disrupt barrier and/or ciliary function, which is regulated by sex steroids and by bitter/sweet taste receptors. Further epidemiological studies and neurodevelopmental and behavioural research is warranted to determine the relevance of large number of suspect candidates whose addition to the environment, household, food and cosmetics might be fuelling the autism epidemic in a gene-dependent manner.

  11. Gene expression promoted by the SV40 DNA targeting sequence and the hypoxia-responsive element under normoxia and hypoxia.

    PubMed

    Sacramento, C B; Moraes, J Z; Denapolis, P M A; Han, S W

    2010-08-01

    The main objective of the present study was to find suitable DNA-targeting sequences (DTS) for the construction of plasmid vectors to be used to treat ischemic diseases. The well-known Simian virus 40 nuclear DTS (SV40-DTS) and hypoxia-responsive element (HRE) sequences were used to construct plasmid vectors to express the human vascular endothelial growth factor gene (hVEGF). The rate of plasmid nuclear transport and consequent gene expression under normoxia (20% O2) and hypoxia (less than 5% O2) were determined. Plasmids containing the SV40-DTS or HRE sequences were constructed and used to transfect the A293T cell line (a human embryonic kidney cell line) in vitro and mouse skeletal muscle cells in vivo. Plasmid transport to the nucleus was monitored by real-time PCR, and the expression level of the hVEGF gene was measured by ELISA. The in vitro nuclear transport efficiency of the SV40-DTS plasmid was about 50% lower under hypoxia, while the HRE plasmid was about 50% higher under hypoxia. Quantitation of reporter gene expression in vitro and in vivo, under hypoxia and normoxia, confirmed that the SV40-DTS plasmid functioned better under normoxia, while the HRE plasmid was superior under hypoxia. These results indicate that the efficiency of gene expression by plasmids containing DNA binding sequences is affected by the concentration of oxygen in the medium.

  12. MicroRNA-27a Regulates Beta Cardiac Myosin Heavy Chain Gene Expression by Targeting Thyroid Hormone Receptor β1 in Neonatal Rat Ventricular Myocytes▿

    PubMed Central

    Nishi, Hitoo; Ono, Koh; Horie, Takahiro; Nagao, Kazuya; Kinoshita, Minako; Kuwabara, Yasuhide; Watanabe, Shin; Takaya, Tomohide; Tamaki, Yodo; Takanabe-Mori, Rieko; Wada, Hiromichi; Hasegawa, Koji; Iwanaga, Yoshitaka; Kawamura, Teruhisa; Kita, Toru; Kimura, Takeshi

    2011-01-01

    MicroRNAs (miRNAs), small noncoding RNAs, are negative regulators of gene expression and play important roles in gene regulation in the heart. To examine the role of miRNAs in the expression of the two isoforms of the cardiac myosin heavy chain (MHC) gene, α- and β-MHC, which regulate cardiac contractility, endogenous miRNAs were downregulated in neonatal rat ventricular myocytes (NRVMs) using lentivirus-mediated small interfering RNA (siRNA) against Dicer, an essential enzyme for miRNA biosynthesis, and MHC expression levels were examined. As a result, Dicer siRNA could downregulate endogenous miRNAs simultaneously and the β-MHC gene but not α-MHC, which implied that specific miRNAs could upregulate the β-MHC gene. Among 19 selected miRNAs, miR-27a was found to most strongly upregulate the β-MHC gene but not α-MHC. Moreover, β-MHC protein was downregulated by silencing of endogenous miR-27a. Through a bioinformatics screening using TargetScan, we identified thyroid hormone receptor β1 (TRβ1), which negatively regulates β-MHC transcription, as a target of miR-27a. Moreover, miR-27a was demonstrated to modulate β-MHC gene regulation via thyroid hormone signaling and to be upregulated during the differentiation of mouse embryonic stem (ES) cells or in hypertrophic hearts in association with β-MHC gene upregulation. These findings suggested that miR-27a regulates β-MHC gene expression by targeting TRβ1 in cardiomyocytes. PMID:21149577

  13. Generation of antibody- and B cell-deficient pigs by targeted disruption of the J-region gene segment of the heavy chain locus.

    PubMed

    Mendicino, M; Ramsoondar, J; Phelps, C; Vaught, T; Ball, S; LeRoith, T; Monahan, J; Chen, S; Dandro, A; Boone, J; Jobst, P; Vance, A; Wertz, N; Bergman, Z; Sun, X-Z; Polejaeva, I; Butler, J; Dai, Y; Ayares, D; Wells, K

    2011-06-01

    A poly(A)-trap gene targeting strategy was used to disrupt the single functional heavy chain (HC) joining region (J(H)) of swine in primary fibroblasts. Genetically modified piglets were then generated via somatic cell nuclear transfer (SCNT) and bred to yield litters comprising J(H) wild-type littermate (+/+), J(H) heterozygous knockout (±) and J(H) homozygous knockout (-/-) piglets in the expected Mendelian ratio of 1:2:1. There are only two other targeted loci previously published in swine, and this is the first successful poly(A)-trap strategy ever published in a livestock species. In either blood or secondary lymphoid tissues, flow cytometry, RT-PCR and ELISA detected no circulating IgM(+) B cells, and no transcription or secretion of immunoglobulin (Ig) isotypes, respectively in J(H) -/- pigs. Histochemical and immunohistochemical (IHC) studies failed to detect lymph node (LN) follicles or CD79α(+) B cells, respectively in J(H) -/- pigs. T cell receptor (TCR)(β) transcription and T cells were detected in J(H) -/- pigs. When reared conventionally, J(H) -/- pigs succumbed to bacterial infections after weaning. These antibody (Ab)- and B cell-deficient pigs have significant value as models for both veterinary and human research to discriminate cellular and humoral protective immunity to infectious agents. Thus, these pigs may aid in vaccine development for infectious agents such as the pandemic porcine reproductive and respiratory syndrome virus (PRRSV) and H1N1 swine flu. These pigs are also a first significant step towards generating a pig that expresses fully human, antigen-specific polyclonal Ab to target numerous incurable infectious diseases with high unmet clinical need.

  14. The new confocal heavy ion microprobe beamline at ANSTO: The first microprobe resolution tests and applications for elemental imaging and analysis

    NASA Astrophysics Data System (ADS)

    Pastuovic, Z.; Siegele, R.; Cohen, D. D.; Mann, M.; Ionescu, M.; Button, D.; Long, S.

    2017-08-01

    The Centre for Accelerator Science facility at ANSTO has been expanded with the new NEC 6 MV ;SIRIUS; accelerator system in 2015. In this paper we present a detailed description of the new nuclear microprobe-Confocal Heavy Ion Micro-Probe (CHIMP) together with results of the microprobe resolution testing and the elemental analysis performed on typical samples of mineral ore deposits and hyper-accumulating plants regularly measured at ANSTO. The CHIMP focusing and scanning systems are based on the OM-150 Oxford quadrupole triplet and the OM-26 separated scan-coil doublet configurations. A maximum ion rigidity of 38.9 amu-MeV was determined for the following nuclear microprobe configuration: the distance from object aperture to collimating slits of 5890 mm, the working distance of 165 mm and the lens bore diameter of 11 mm. The overall distance from the object to the image plane is 7138 mm. The CHIMP beamline has been tested with the 3 MeV H+ and 6 MeV He2+ ion beams. The settings of the object and collimating apertures have been optimized using the WinTRAX simulation code for calculation of the optimum acceptance settings in order to obtain the highest possible ion current for beam spot sizes of 1 μm and 5 μm. For optimized aperture settings of the CHIMP the beam brightness was measured to be ∼0.9 pA μm-2 mrad-2 for 3 MeV H+ ions, while the brightness of ∼0.4 pA μm-2 mrad-2 was measured for 6 MeV He2+ ions. The smallest beam sizes were achieved using a microbeam with reduced particle rate of 1000 Hz passing through the object slit apertures several micrometers wide. Under these conditions a spatial resolution of ∼0.6 μm × 1.5 μm for 3 MeV H+ and ∼1.8 μm × 1.8 μm for 6 MeV He2+ microbeams in horizontal (and vertical) dimension has been achieved. The beam sizes were verified using STIM imaging on 2000 and 1000 mesh Cu electron microscope grids.

  15. Superiority of Low Energy 160 KV X-Rays Compared to High Energy 6 MV X-Rays in Heavy Element Radiosensitization for Cancer Treatment

    NASA Astrophysics Data System (ADS)

    Lim, Sara N.; Pradhan, Anil K.; Nahar, Sultana N.; Barth, Rolf F.; Yang, Weilian; Nakkula, Robin J.; Palmer, Alycia; Turro, Claudia

    2013-06-01

    High energy X-rays in the MeV range are generally employed in conventional radiation therapy from linear accelerators (LINAC) to ensure sufficient penetration depths. However, lower energy X-rays in the keV range may be more effective when coupled with heavy element (high-Z or HZ) radiosensitizers. Numerical simulations of X-ray energy deposition for tumo