WorldWideScience

Sample records for relating sub-cellular metal

  1. Metal-induced stress in bivalves living along a gradient of Cd contamination: relating sub-cellular metal distribution to population-level responses

    International Nuclear Information System (INIS)

    Perceval, Olivier; Couillard, Yves; Pinel-Alloul, Bernadette; Giguere, Anik; Campbell, Peter G.C.

    2004-01-01

    The use of biomarkers to assess the impacts of contaminants on aquatic ecosystems has noticeably increased over the past few years. Few of these studies, however, have contributed to the prediction of ecologically significant effects (i.e., at the population or community levels). The present field study was designed to evaluate the potential of metallothionein (MT) and sub-cellular metal partitioning measurements for predicting toxic effects at higher levels of the biological organization in freshwater bivalves (Pyganodon grandis) chronically exposed to Cd. For that purpose, we quantitatively sampled P. grandis populations in the littoral zone of nine lakes on the Precambrian Canadian Shield during two consecutive summers (1998 and 1999); lakes were characterized by contrasting Cd levels but similar trophic status. We tested relationships between the population status of P. grandis (i.e., growth parameters, density, biomass, secondary production, turnover ratio and cumulative fecundity) and (i) ambient Cd concentrations, (ii) sub-organismal responses (MT concentrations in the gill cytosol of individuals and Cd concentrations in three metal-ligand pools identified as M-HMW, the high molecular weight pool, M-MT, the metallothionein-like pool and M-LMW, the low molecular weight pool) and (iii) ecological confounding factors (food resources, presence of host fishes for the obligatory parasitic larval stage of P. grandis). Our results show that littoral density, live weight, dry viscera biomass, production and cumulative fecundity decreased with increasing concentrations of the free-cadmium ion in the environment (Pearson's r ranging from -0.63 to -0.78). On the other hand, theoretical maximum shell lengths (L ∞ ) in our populations were related to both the dissolved Ca concentration and food quality (sestonic C and N concentrations). Overall, Cd concentrations in the gill cytosolic HMW pool of the individual molluscs were the biomarker response that was most

  2. Parasites modify sub-cellular partitioning of metals in the gut of fish

    Energy Technology Data Exchange (ETDEWEB)

    Oyoo-Okoth, Elijah, E-mail: elijaoyoo2009@gmail.com [Division of Environmental Health, School of Environmental Studies, Moi University, P.O. Box 3900, Eldoret (Kenya); Department of Aquatic Ecology and Ecotoxicology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 9424/1090 GE (Netherlands); Admiraal, Wim [Department of Aquatic Ecology and Ecotoxicology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 9424/1090 GE (Netherlands); Osano, Odipo [Division of Environmental Health, School of Environmental Studies, Moi University, P.O. Box 3900, Eldoret (Kenya); Kraak, Michiel H.S. [Department of Aquatic Ecology and Ecotoxicology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 9424/1090 GE (Netherlands); Gichuki, John; Ogwai, Caleb [Kenya Marine and Fisheries Research Institute, P.O. Box 1881, Kisumu (Kenya)

    2012-01-15

    Infestation of fish by parasites may influence metal accumulation patterns in the host. However, the subcellular mechanisms of these processes have rarely been studied. Therefore, this study determined how a cyprinid fish (Rastrineobola argentea) partitioned four metals (Cd, Cr, Zn and Cu) in the subcellular fractions of the gut in presence of an endoparasite (Ligula intestinalis). The fish were sampled along four sites in Lake Victoria, Kenya differing in metal contamination. Accumulation of Cd, Cr and Zn was higher in the whole body and in the gut of parasitized fish compared to non-parasitized fish, while Cu was depleted in parasitized fish. Generally, for both non-parasitized and parasitized fish, Cd, Cr and Zn partitioned in the cytosolic fractions and Cu in the particulate fraction. Metal concentrations in organelles within the particulate fractions of the non-parasitized fish were statistically similar except for Cd in the lysosome, while in the parasitized fish, Cd, Cr and Zn were accumulated more by the lysosome and microsomes. In the cytosolic fractions, the non-parasitized fish accumulated Cd, Cr and Zn in the heat stable proteins (HSP), while in the parasitized fish the metals were accumulated in the heat denatured proteins (HDP). On the contrary, Cu accumulated in the HSP in parasitized fish. The present study revealed specific binding of metals to potentially sensitive sub-cellular fractions in fish in the presence of parasites, suggesting interference with metal detoxification, and potentially affecting the health status of fish hosts in Lake Victoria.

  3. Seasonal variations in hepatic Cd and Cu concentrations and in the sub-cellular distribution of these metals in juvenile yellow perch (Perca flavescens)

    International Nuclear Information System (INIS)

    Kraemer, Lisa D.; Campbell, Peter G.C.; Hare, Landis

    2006-01-01

    Temporal fluctuations in metal (Cd and Cu) concentrations were monitored over four months (May to August) in the liver of juvenile yellow perch (Perca flavescens) sampled from four lakes situated along a metal concentration gradient in northwestern Quebec: Lake Opasatica (reference lake, low metal concentrations), Lake Vaudray (moderate metal concentrations) and lakes Osisko and Dufault (high metal levels). The objectives of this study were to determine if hepatic metal concentrations and metal-handling strategies at the sub-cellular level varied seasonally. Our results showed that Cd and Cu concentrations varied most, in both absolute and relative values, in fish with the highest hepatic metal concentrations, whereas fish sampled from the reference lake did not show any significant variation. To examine the sub-cellular partitioning of these two metals, we used a differential centrifugation technique that allowed the separation of cellular debris, metal detoxified fractions (heat-stable proteins such as metallothionein) and metal sensitive fractions (heat-denaturable proteins (HDP) and organelles). Whereas Cd concentrations in organelle and HDP fractions were maintained at low concentrations in perch from Lakes Opasatica and Vaudray, concentrations in these sensitive fractions were higher and more variable in perch from Lakes Dufault and Osisko, suggesting that there may be some liver dysfunction in these two fish populations. Similarly, Cu concentrations in these sensitive fractions were higher and more variable in perch from the two most Cu-contaminated lakes (Dufault and Osisko) than in perch from the other two lakes, suggesting a breakdown of homeostatic control over this metal. These results suggest not only that metal concentrations vary seasonally, but also that concentrations vary most in fish from contaminated sites. Furthermore, at the sub-cellular level, homeostatic control of metal concentrations in metal-sensitive fractions is difficult to maintain in

  4. Sub-cellular partitioning of Zn, Cu, Cd and Pb in the digestive gland of native Octopus vulgaris exposed to different metal concentrations (Portugal)

    Energy Technology Data Exchange (ETDEWEB)

    Raimundo, J. [National Institute for Agronomy and Fisheries Research - IPIMAR, Av. Brasilia, 1449-006 Lisbon (Portugal)], E-mail: jraimundo@ipimar.pt; Vale, C. [National Institute for Agronomy and Fisheries Research - IPIMAR, Av. Brasilia, 1449-006 Lisbon (Portugal); Duarte, R.; Moura, I. [REQUIMTE - CQFB, Department of Chemistry, Faculty of Sciences and Technology, New University of Lisbon, Qta Torre, 2829-516 Monte da Caparica (Portugal)

    2008-02-15

    Concentrations of Zn, Cu, Cd and Pb and their sub-cellular distributions were determined in composite samples of digestive glands of the common octopus, Octopus vulgaris caught from two areas of the Portuguese coast characterised by contrasting metal contamination. Minor contents of Zn (1%), Cu (2%), Cd (6%) and Pb (7%) were found in the insoluble fraction, consisting of nuclei, mitochondria, lysosomes and microsome operationally separated from the whole digestive gland through a sequential centrifugation. A tendency for linear relationships between metal concentrations in nuclei, mitochondria, lysosomes and whole digestive gland was observed. These relationships suggest that despite low metal content organelles responded to the increasing accumulated metals, which means that detoxifying mechanism in cytosol was incomplete. Poorer correlations between microsome and whole digestive gland did not point to metal toxicity in the analysed compartments. However, the high accumulated Cd indicated that O. vulgaris is an important vehicle of this element to its predators in the coastal environment.

  5. Sub-cellular partitioning of Zn, Cu, Cd and Pb in the digestive gland of native Octopus vulgaris exposed to different metal concentrations (Portugal)

    International Nuclear Information System (INIS)

    Raimundo, J.; Vale, C.; Duarte, R.; Moura, I.

    2008-01-01

    Concentrations of Zn, Cu, Cd and Pb and their sub-cellular distributions were determined in composite samples of digestive glands of the common octopus, Octopus vulgaris caught from two areas of the Portuguese coast characterised by contrasting metal contamination. Minor contents of Zn (1%), Cu (2%), Cd (6%) and Pb (7%) were found in the insoluble fraction, consisting of nuclei, mitochondria, lysosomes and microsome operationally separated from the whole digestive gland through a sequential centrifugation. A tendency for linear relationships between metal concentrations in nuclei, mitochondria, lysosomes and whole digestive gland was observed. These relationships suggest that despite low metal content organelles responded to the increasing accumulated metals, which means that detoxifying mechanism in cytosol was incomplete. Poorer correlations between microsome and whole digestive gland did not point to metal toxicity in the analysed compartments. However, the high accumulated Cd indicated that O. vulgaris is an important vehicle of this element to its predators in the coastal environment

  6. Sub-cellular localisation of fukutin related protein in different cell lines and in the muscle of patients with MDC1C and LGMD2I

    DEFF Research Database (Denmark)

    Torelli, Silvia; Brown, Susan C; Brockington, Martin

    2005-01-01

    MDC1C and LGMD2I are two allelic forms of muscular dystrophies caused by mutations in the gene encoding for fukutin related protein (FKRP). FKRP encodes for a putative glycosyltransferase, the precise function of which is unknown. However, the marked reduction of alpha-dystroglycan glycosylation ...

  7. Determining the sub-cellular localization of proteins within Caenorhabditis elegans body wall muscle.

    Science.gov (United States)

    Meissner, Barbara; Rogalski, Teresa; Viveiros, Ryan; Warner, Adam; Plastino, Lorena; Lorch, Adam; Granger, Laure; Segalat, Laurent; Moerman, Donald G

    2011-01-01

    Determining the sub-cellular localization of a protein within a cell is often an essential step towards understanding its function. In Caenorhabditis elegans, the relatively large size of the body wall muscle cells and the exquisite organization of their sarcomeres offer an opportunity to identify the precise position of proteins within cell substructures. Our goal in this study is to generate a comprehensive "localizome" for C. elegans body wall muscle by GFP-tagging proteins expressed in muscle and determining their location within the cell. For this project, we focused on proteins that we know are expressed in muscle and are orthologs or at least homologs of human proteins. To date we have analyzed the expression of about 227 GFP-tagged proteins that show localized expression in the body wall muscle of this nematode (e.g. dense bodies, M-lines, myofilaments, mitochondria, cell membrane, nucleus or nucleolus). For most proteins analyzed in this study no prior data on sub-cellular localization was available. In addition to discrete sub-cellular localization we observe overlapping patterns of localization including the presence of a protein in the dense body and the nucleus, or the dense body and the M-lines. In total we discern more than 14 sub-cellular localization patterns within nematode body wall muscle. The localization of this large set of proteins within a muscle cell will serve as an invaluable resource in our investigation of muscle sarcomere assembly and function.

  8. Sub-cellular distribution and translocation of TRP channels.

    Science.gov (United States)

    Toro, Carlos A; Arias, Luis A; Brauchi, Sebastian

    2011-01-01

    Cellular electrical activity is the result of a highly complex processes that involve the activation of ion channel proteins. Ion channels make pores on cell membranes that rapidly transit between conductive and non-conductive states, allowing different ions to flow down their electrochemical gradients across cell membranes. In the case of neuronal cells, ion channel activity orchestrates action potentials traveling through axons, enabling electrical communication between cells in distant parts of the body. Somatic sensation -our ability to feel touch, temperature and noxious stimuli- require ion channels able to sense and respond to our peripheral environment. Sensory integration involves the summing of various environmental cues and their conversion into electrical signals. Members of the Transient Receptor Potential (TRP) family of ion channels have emerged as important mediators of both cellular sensing and sensory integration. The regulation of the spatial and temporal distribution of membrane receptors is recognized as an important mechanism for controlling the magnitude of the cellular response and the time scale on which cellular signaling occurs. Several studies have shown that this mechanism is also used by TRP channels to modulate cellular response and ultimately fulfill their physiological function as sensors. However, the inner-working of this mode of control for TRP channels remains poorly understood. The question of whether TRPs intrinsically regulate their own vesicular trafficking or weather the dynamic regulation of TRP channel residence on the cell surface is caused by extrinsic changes in the rates of vesicle insertion or retrieval remain open. This review will examine the evidence that sub-cellular redistribution of TRP channels plays an important role in regulating their activity and explore the mechanisms that control the trafficking of vesicles containing TRP channels.

  9. Combined phase and X-Ray fluorescence imaging at the sub-cellular level

    International Nuclear Information System (INIS)

    Kosior, Ewelina

    2013-01-01

    This work presents some recent developments in the field of hard X-ray imaging applied to biomedical research. As the discipline is evolving quickly, new questions appear and the list of needs becomes bigger. Some of them are dealt with in this manuscript. It has been shown that the ID22NI beamline of the ESRF can serve as a proper experimental setup to investigate diverse aspects of cellular research. Together with its high spatial resolution, high flux and high energy range the experimental setup provides bigger field of view, is less sensitive to radiation damages (while taking phase contrast images) and suits well chemical analysis with emphasis on endogenous metals (Zn, Fe, Mn) but also with a possibility for exogenous one's like these found in nanoparticles (Au, Pt, Ag) study. Two synchrotron-based imaging techniques, fluorescence and phase contrast imaging were used in this research project. They were correlated with each other on a number of biological cases, from bacteria E.coli to various cells (HEK 293, PC12, MRC5VA, red blood cells). The explorations made in the chapter 5 allowed preparation of more established and detailed analysis, described in the next chapter where both techniques, X-ray fluorescence and phase contrast imaging, were exploited in order to access absolute metal projected mass fraction in a whole cell. The final image presents for the first time true quantitative information at the sub-cellular level, not biased by the cell thickness. Thus for the first time a fluorescence map serves as a complete quantitative image of a cell without any risk of misinterpretation. Once both maps are divided by each other pixel by pixel (fluorescence map divided by the phase map) they present a complete and final result of the metal (Zn in this work) projected mass fraction in ppm of dry weight. For the purpose of this calculation the analysis was extended to calibration (non-biological) samples. Polystyrene spheres of a known diameter and known

  10. Sub-cellular force microscopy in single normal and cancer cells.

    Science.gov (United States)

    Babahosseini, H; Carmichael, B; Strobl, J S; Mahmoodi, S N; Agah, M

    2015-08-07

    This work investigates the biomechanical properties of sub-cellular structures of breast cells using atomic force microscopy (AFM). The cells are modeled as a triple-layered structure where the Generalized Maxwell model is applied to experimental data from AFM stress-relaxation tests to extract the elastic modulus, the apparent viscosity, and the relaxation time of sub-cellular structures. The triple-layered modeling results allow for determination and comparison of the biomechanical properties of the three major sub-cellular structures between normal and cancerous cells: the up plasma membrane/actin cortex, the mid cytoplasm/nucleus, and the low nuclear/integrin sub-domains. The results reveal that the sub-domains become stiffer and significantly more viscous with depth, regardless of cell type. In addition, there is a decreasing trend in the average elastic modulus and apparent viscosity of the all corresponding sub-cellular structures from normal to cancerous cells, which becomes most remarkable in the deeper sub-domain. The presented modeling in this work constitutes a unique AFM-based experimental framework to study the biomechanics of sub-cellular structures. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Radiation damage on sub-cellular scales: beyond DNA

    International Nuclear Information System (INIS)

    Byrne, H L; McNamara, A L; Domanova, W; Kuncic, Z; Guatelli, S

    2013-01-01

    This study investigates a model cell as a target for low-dose radiation using Monte Carlo simulations. Mono-energetic electrons and photons are used with initial energies between 10 and 50 keV, relevant to out-of-field radiotherapy scenarios where modern treatment modalities expose relatively large amounts of healthy tissue to low-dose radiation, and also to microbeam cell irradiation studies which show the importance of the cytoplasm as a radiation target. The relative proportions of number of ionizations and total energy deposit in the nucleus and cytoplasm are calculated. We show that for a macroscopic dose of no more than 1 Gy only a few hundred ionizations occur in the nucleus volume whereas the number of ionizations in the cytoplasm is over a magnitude larger. We find that the cell geometry can have an appreciable effect on the energy deposit in the cell and can cause a nonlinear increase in energy deposit with cytoplasm density. We also show that changing the nucleus volume has negligible effect on the total energy deposit but alters the relative proportion deposited in the nucleus and cytoplasm; the nucleus volume must increase to approximately the same volume as the cytoplasm before the energy deposit in the nucleus matches that in the cytoplasm. Additionally we find that energy deposited by electrons is generally insensitive to spatial variations in chemical composition, which can be attributed to negligible differences in electron stopping power for cytoplasm and nucleus materials. On the other hand, we find that chemical composition can affect energy deposited by photons due to non-negligible differences in attenuation coefficients. These results are of relevance in considering radiation effects in healthy cells, which tend to have smaller nuclei. Our results further show that the cytoplasm and organelles residing therein can be important targets for low-dose radiation damage in healthy cells and warrant investigation as much as the conventional focus

  12. Sub-cellular force microscopy in single normal and cancer cells

    International Nuclear Information System (INIS)

    Babahosseini, H.; Carmichael, B.; Strobl, J.S.; Mahmoodi, S.N.; Agah, M.

    2015-01-01

    This work investigates the biomechanical properties of sub-cellular structures of breast cells using atomic force microscopy (AFM). The cells are modeled as a triple-layered structure where the Generalized Maxwell model is applied to experimental data from AFM stress-relaxation tests to extract the elastic modulus, the apparent viscosity, and the relaxation time of sub-cellular structures. The triple-layered modeling results allow for determination and comparison of the biomechanical properties of the three major sub-cellular structures between normal and cancerous cells: the up plasma membrane/actin cortex, the mid cytoplasm/nucleus, and the low nuclear/integrin sub-domains. The results reveal that the sub-domains become stiffer and significantly more viscous with depth, regardless of cell type. In addition, there is a decreasing trend in the average elastic modulus and apparent viscosity of the all corresponding sub-cellular structures from normal to cancerous cells, which becomes most remarkable in the deeper sub-domain. The presented modeling in this work constitutes a unique AFM-based experimental framework to study the biomechanics of sub-cellular structures. - Highlights: • The cells are modeled as a triple-layered structure using Generalized Maxwell model. • The sub-domains include membrane/cortex, cytoplasm/nucleus, and nuclear/integrin. • Biomechanics of corresponding sub-domains are compared among normal and cancer cells. • Viscoelasticity of sub-domains show a decreasing trend from normal to cancer cells. • The decreasing trend becomes most significant in the deeper sub-domain

  13. Sub-cellular force microscopy in single normal and cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Babahosseini, H. [VT MEMS Laboratory, The Bradley Department of Electrical and Computer Engineering, Blacksburg, VA 24061 (United States); Carmichael, B. [Nonlinear Intelligent Structures Laboratory, Department of Mechanical Engineering, University of Alabama, Tuscaloosa, AL 35487-0276 (United States); Strobl, J.S. [VT MEMS Laboratory, The Bradley Department of Electrical and Computer Engineering, Blacksburg, VA 24061 (United States); Mahmoodi, S.N., E-mail: nmahmoodi@eng.ua.edu [Nonlinear Intelligent Structures Laboratory, Department of Mechanical Engineering, University of Alabama, Tuscaloosa, AL 35487-0276 (United States); Agah, M., E-mail: agah@vt.edu [VT MEMS Laboratory, The Bradley Department of Electrical and Computer Engineering, Blacksburg, VA 24061 (United States)

    2015-08-07

    This work investigates the biomechanical properties of sub-cellular structures of breast cells using atomic force microscopy (AFM). The cells are modeled as a triple-layered structure where the Generalized Maxwell model is applied to experimental data from AFM stress-relaxation tests to extract the elastic modulus, the apparent viscosity, and the relaxation time of sub-cellular structures. The triple-layered modeling results allow for determination and comparison of the biomechanical properties of the three major sub-cellular structures between normal and cancerous cells: the up plasma membrane/actin cortex, the mid cytoplasm/nucleus, and the low nuclear/integrin sub-domains. The results reveal that the sub-domains become stiffer and significantly more viscous with depth, regardless of cell type. In addition, there is a decreasing trend in the average elastic modulus and apparent viscosity of the all corresponding sub-cellular structures from normal to cancerous cells, which becomes most remarkable in the deeper sub-domain. The presented modeling in this work constitutes a unique AFM-based experimental framework to study the biomechanics of sub-cellular structures. - Highlights: • The cells are modeled as a triple-layered structure using Generalized Maxwell model. • The sub-domains include membrane/cortex, cytoplasm/nucleus, and nuclear/integrin. • Biomechanics of corresponding sub-domains are compared among normal and cancer cells. • Viscoelasticity of sub-domains show a decreasing trend from normal to cancer cells. • The decreasing trend becomes most significant in the deeper sub-domain.

  14. Optically-controlled platforms for transfection and single- and sub-cellular surgery

    DEFF Research Database (Denmark)

    Villangca, Mark Jayson; Casey, Duncan; Glückstad, Jesper

    2015-01-01

    and specificity of optical trapping in conjunction with other modalities to perform single and sub-cellular surgery. These tools form highly tuneable platforms for the delivery or removal of material from cells of interest, but can simultaneously excite fluorescent probes for imaging purposes or plasmonic...... structures for very local heating. We discuss both the history and recent applications of the field, highlighting the key findings and developments over the last 40 years of biophotonics research....

  15. The UL24 protein of herpes simplex virus 1 affects the sub-cellular distribution of viral glycoproteins involved in fusion

    Energy Technology Data Exchange (ETDEWEB)

    Ben Abdeljelil, Nawel; Rochette, Pierre-Alexandre; Pearson, Angela, E-mail: angela.pearson@iaf.inrs.ca

    2013-09-15

    Mutations in UL24 of herpes simplex virus type 1 can lead to a syncytial phenotype. We hypothesized that UL24 affects the sub-cellular distribution of viral glycoproteins involved in fusion. In non-immortalized human foreskin fibroblasts (HFFs) we detected viral glycoproteins B (gB), gD, gH and gL present in extended blotches throughout the cytoplasm with limited nuclear membrane staining; however, in HFFs infected with a UL24-deficient virus (UL24X), staining for the viral glycoproteins appeared as long, thin streaks running across the cell. Interestingly, there was a decrease in co-localized staining of gB and gD with F-actin at late times in UL24X-infected HFFs. Treatment with chemical agents that perturbed the actin cytoskeleton hindered the formation of UL24X-induced syncytia in these cells. These data support a model whereby the UL24 syncytial phenotype results from a mislocalization of viral glycoproteins late in infection. - Highlights: • UL24 affects the sub-cellular distribution of viral glycoproteins required for fusion. • Sub-cellular distribution of viral glycoproteins varies in cell-type dependent manner. • Drugs targeting actin microfilaments affect formation of UL24-related syncytia in HFFs.

  16. Oil Spill Related Heavy Metal: A Review

    International Nuclear Information System (INIS)

    Ahmad Dasuki Mustafa; Hafizan Juahir; Kamaruzzaman Yunus; Mohammad Azizi Amran; Che Noraini Che Hasnam; Fazureen Azaman; Ismail Zainal Abidin; Syahril Hirman Azmee; Nur Hishaam Sulaiman

    2015-01-01

    Oil spill occurs every day worldwide and oil contamination is a significant contributor for the higher levels of heavy metals in the environment. This study is purposely to summarize the heavy metals which significant to major oil spill incidents around the world and effects of toxic metals to human health. The study performed a comprehensive review of relevant scientific journal articles and government documents concerning heavy metals contamination and oil spills. Overall, the heavy metals most frequently been detected in oil spill related study where Pb>Ni>V>Zn>Cd and caused many effects to human health especially cancer. In conclusion, the comparison of heavy metal level between the post - spill and baseline levels must be done, and implementation of continuous monitoring of heavy metal. In addition, the result based on the strategies must be transparent to public in order to maintaining human health. (author)

  17. Visualizing Escherichia coli sub-cellular structure using sparse deconvolution Spatial Light Interference Tomography.

    Directory of Open Access Journals (Sweden)

    Mustafa Mir

    Full Text Available Studying the 3D sub-cellular structure of living cells is essential to our understanding of biological function. However, tomographic imaging of live cells is challenging mainly because they are transparent, i.e., weakly scattering structures. Therefore, this type of imaging has been implemented largely using fluorescence techniques. While confocal fluorescence imaging is a common approach to achieve sectioning, it requires fluorescence probes that are often harmful to the living specimen. On the other hand, by using the intrinsic contrast of the structures it is possible to study living cells in a non-invasive manner. One method that provides high-resolution quantitative information about nanoscale structures is a broadband interferometric technique known as Spatial Light Interference Microscopy (SLIM. In addition to rendering quantitative phase information, when combined with a high numerical aperture objective, SLIM also provides excellent depth sectioning capabilities. However, like in all linear optical systems, SLIM's resolution is limited by diffraction. Here we present a novel 3D field deconvolution algorithm that exploits the sparsity of phase images and renders images with resolution beyond the diffraction limit. We employ this label-free method, called deconvolution Spatial Light Interference Tomography (dSLIT, to visualize coiled sub-cellular structures in E. coli cells which are most likely the cytoskeletal MreB protein and the division site regulating MinCDE proteins. Previously these structures have only been observed using specialized strains and plasmids and fluorescence techniques. Our results indicate that dSLIT can be employed to study such structures in a practical and non-invasive manner.

  18. Femtosecond laser nanosurgery of sub-cellular structures in HeLa cells by employing Third Harmonic Generation imaging modality as diagnostic tool.

    Science.gov (United States)

    Tserevelakis, George J; Psycharakis, Stylianos; Resan, Bojan; Brunner, Felix; Gavgiotaki, Evagelia; Weingarten, Kurt; Filippidis, George

    2012-02-01

    Femtosecond laser assisted nanosurgery of microscopic biological specimens is a relatively new technique which allows the selective disruption of sub-cellular structures without causing any undesirable damage to the surrounding regions. The targeted structures have to be stained in order to be clearly visualized for the nanosurgery procedure. However, the validation of the final nanosurgery result is difficult, since the targeted structure could be simply photobleached rather than selectively destroyed. This fact comprises a main drawback of this technique. In our study we employed a multimodal system which integrates non-linear imaging modalities with nanosurgery capabilities, for the selective disruption of sub-cellular structures in HeLa cancer cells. Third Harmonic Generation (THG) imaging modality was used as a tool for the identification of structures that were subjected to nanosurgery experiments. No staining of the biological samples was required, since THG is an intrinsic property of matter. Furthermore, cells' viability after nanosurgery processing was verified via Two Photon Excitation Fluorescence (TPEF) measurements. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Imaging of Caenorhabditis elegans samples and sub-cellular localization of new generation photosensitizers for photodynamic therapy, using non-linear microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Filippidis, G [Institute of Electronic Structure and Laser, Foundation of Research and Technology-Hellas, PO Box 1527, 71110 Heraklion (Greece); Kouloumentas, C [Institute of Electronic Structure and Laser, Foundation of Research and Technology-Hellas, PO Box 1527, 71110 Heraklion (Greece); Kapsokalyvas, D [Institute of Electronic Structure and Laser, Foundation of Research and Technology-Hellas, PO Box 1527, 71110 Heraklion (Greece); Voglis, G [Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology, Heraklion 71110, Crete (Greece); Tavernarakis, N [Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology, Heraklion 71110, Crete (Greece); Papazoglou, T G [Institute of Electronic Structure and Laser, Foundation of Research and Technology-Hellas, PO Box 1527, 71110 Heraklion (Greece)

    2005-08-07

    Two-photon excitation fluorescence (TPEF) and second-harmonic generation (SHG) are relatively new promising tools for the imaging and mapping of biological structures and processes at the microscopic level. The combination of the two image-contrast modes in a single instrument can provide unique and complementary information concerning the structure and the function of tissues and individual cells. The extended application of this novel, innovative technique by the biological community is limited due to the high price of commercial multiphoton microscopes. In this study, a compact, inexpensive and reliable setup utilizing femtosecond pulses for excitation was developed for the TPEF and SHG imaging of biological samples. Specific cell types of the nematode Caenorhabditis elegans were imaged. Detection of the endogenous structural proteins of the worm, which are responsible for observation of SHG signals, was achieved. Additionally, the binding of different photosensitizers in the HL-60 cell line was investigated, using non-linear microscopy. The sub-cellular localization of photosensitizers of a new generation, very promising for photodynamic therapy (PDT) (Hypericum perforatum L. extracts) was achieved. The sub-cellular localization of these novel photosensitizers was linked with their photodynamic action during PDT, and the possible mechanisms for cell killing have been elucidated.

  20. Movies of cellular and sub-cellular motion by digital holographic microscopy

    Directory of Open Access Journals (Sweden)

    Yu Lingfeng

    2006-03-01

    Full Text Available Abstract Background Many biological specimens, such as living cells and their intracellular components, often exhibit very little amplitude contrast, making it difficult for conventional bright field microscopes to distinguish them from their surroundings. To overcome this problem phase contrast techniques such as Zernike, Normarsky and dark-field microscopies have been developed to improve specimen visibility without chemically or physically altering them by the process of staining. These techniques have proven to be invaluable tools for studying living cells and furthering scientific understanding of fundamental cellular processes such as mitosis. However a drawback of these techniques is that direct quantitative phase imaging is not possible. Quantitative phase imaging is important because it enables determination of either the refractive index or optical thickness variations from the measured optical path length with sub-wavelength accuracy. Digital holography is an emergent phase contrast technique that offers an excellent approach in obtaining both qualitative and quantitative phase information from the hologram. A CCD camera is used to record a hologram onto a computer and numerical methods are subsequently applied to reconstruct the hologram to enable direct access to both phase and amplitude information. Another attractive feature of digital holography is the ability to focus on multiple focal planes from a single hologram, emulating the focusing control of a conventional microscope. Methods A modified Mach-Zender off-axis setup in transmission is used to record and reconstruct a number of holographic amplitude and phase images of cellular and sub-cellular features. Results Both cellular and sub-cellular features are imaged with sub-micron, diffraction-limited resolution. Movies of holographic amplitude and phase images of living microbes and cells are created from a series of holograms and reconstructed with numerically adjustable

  1. Sub-cellular damage by copper in the cnidarian Zoanthus robustus.

    Science.gov (United States)

    Grant, A; Trompf, K; Seung, D; Nivison-Smith, L; Bowcock, H; Kresse, H; Holmes, S; Radford, J; Morrow, P

    2010-09-01

    Sessile organisms may experience chronic exposure to copper that is released into the marine environment from antifoulants and stormwater runoff. We have identified the site of damage caused by copper to the symbiotic cnidarian, Zoanthus robustus (Anthozoa, Hexacorallia). External changes to the zoanthids were apparent when compared with controls. The normally flexible bodies contracted and became rigid. Histological examination of the zoanthid tissue revealed that copper had caused sub-cellular changes to proteins within the extracellular matrix (ECM) of the tubular body. Collagen in the ECM and the internal septa increased in thickness to five and seven times that of controls respectively. The epithelium, which stained for elastin, was also twice as thick and tough to cut, but exposure to copper did not change the total amount of desmosine which is found only in elastin. We conclude that copper stimulated collagen synthesis in the ECM and also caused cross-linking of existing proteins. However, there was no expulsion of the symbiotic algae (Symbiodinium sp.) and no effect on algal pigments or respiration (44, 66 and 110 microg Cu L(-1)). A decrease in net photosynthesis was observed only at the highest copper concentration (156 microg Cu L(-1)). These results show that cnidarians may be more susceptible to damage by copper than their symbiotic algae. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  2. Heavy metals and related trace elements

    International Nuclear Information System (INIS)

    Leland, H.V.; Luoma, S.N.; Wilkes, D.J.

    1977-01-01

    A review is given of heavy metals and related trace elements in the aquatic environment. Other reviews and bibliographies are cited, dealing with the metabolism and transport of metal ions and with the toxic effects of stable and radioactive trace metals on aquatic organisms. The sources of trace elements in natural waters are discussed. It is suggested that atmospheric inputs of several trace metals comprise sizable fractions of total inputs to the Great Lakes and continental shelf waters. Information on stack emissions of trace elements from a coal-fired steam plant was used to estimate the likely range of air concentrations and inputs to a forested watershed in Tennessee. Some basic concepts of cycling of elements through aquatic communities were examined, such as the Pb, Mn and Zn concentrations in sediment and estuarine plants and animals colonizing dredge-spoil disposal areas. The use of plants as biological indicators of trace element contamination was outlined, as well as bioaccumulation in aquatic fauna. The effects of environmental factors on the kinetics of element exchange were noted, for example the influx rates of Cs 137 in tubificid worms, and Co 60 and Zn 65 in shrimp were shown to be temperature dependent. The toxicity of heavy metals on aquatic fauna was discussed, such as the histopathological lesions in the kidney and liver of fishes caused by heavy metals, and the effects of Hg and Cu on the olfactory response of rainbow trout

  3. Quantifying the Sub-Cellular Distributions of Gold Nanospheres Uptaken by Cells through Stepwise, Site-Selective Etching.

    Science.gov (United States)

    Xia, Younan; Huo, Da

    2018-04-10

    A quantitative understanding of the sub-cellular distributions of nanoparticles uptaken by cells is important to the development of nanomedicine. With Au nanospheres as a model system, here we demonstrate, for the first time, how to quantify the numbers of nanoparticles bound to plasma membrane, accumulated in cytosol, and entrapped in lysosomes, respectively, through stepwise, site-selective etching. Our results indicate that the chance for nanoparticles to escape from lysosomes is insensitive to the presence of targeting ligand although ligand-receptor binding has been documented as a critical factor in triggering internalization. Furthermore, the presence of serum proteins is shown to facilitate the binding of nanoparticles to plasma membrane lacking the specific receptor. Collectively, these findings confirm the potential of stepwise etching in quantitatively analyzing the sub-cellular distributions of nanoparticles uptaken by cells in an effort to optimize the therapeutic effect. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Direct speciation analysis of arsenic in sub-cellular compartments using micro-X-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Bacquart, Thomas; Deves, Guillaume; Ortega, Richard

    2010-01-01

    Identification of arsenic chemical species at a sub-cellular level is a key to understanding the mechanisms involved in arsenic toxicology and antitumor pharmacology. When performed with a microbeam, X-ray absorption near-edge structure (μ-XANES) enables the direct speciation analysis of arsenic in sub-cellular compartments avoiding cell fractionation and other preparation steps that might modify the chemical species. This methodology couples tracking of cellular organelles in a single cell by confocal or epifluorescence microscopy with local analysis of chemical species by μ-XANES. Here we report the results obtained with a μ-XANES experimental setup based on Kirkpatrick-Baez X-ray focusing optics that maintains high flux of incoming radiation (>10 11 ph/s) at micrometric spatial resolution (1.5x4.0 μm 2 ). This original experimental setup enabled the direct speciation analysis of arsenic in sub-cellular organelles with a 10 -15 g detection limit. μ-XANES shows that inorganic arsenite, As(OH) 3 , is the main form of arsenic in the cytosol, nucleus, and mitochondrial network of cultured cancer cells exposed to As 2 O 3 . On the other hand, a predominance of As(III) species is observed in HepG2 cells exposed to As(OH) 3 with, in some cases, oxidation to a pentavalent form in nuclear structures of HepG2 cells. The observation of intra-nuclear mixed redox states suggests an inter-individual variability in a cell population that can only be evidenced with direct sub-cellular speciation analysis.

  5. Sub-cellular trafficking of phytochemicals explored using auto-fluorescent compounds in maize cells

    Directory of Open Access Journals (Sweden)

    Grotewold Erich

    2003-12-01

    Full Text Available Abstract Background Little is known regarding the trafficking mechanisms of small molecules within plant cells. It remains to be established whether phytochemicals are transported by pathways similar to those used by proteins, or whether the expansion of metabolic pathways in plants was associated with the evolution of novel trafficking pathways. In this paper, we exploited the induction of green and yellow auto-fluorescent compounds in maize cultured cells by the P1 transcription factor to investigate their targeting to the cell wall and vacuole, respectively. Results We investigated the accumulation and sub-cellular localization of the green and yellow auto-fluorescent compounds in maize BMS cells expressing the P1 transcription factor from an estradiol inducible promoter. We established that the yellow fluorescent compounds accumulate inside the vacuole in YFBs that resemble AVIs. The green fluorescent compounds accumulate initially in the cytoplasm in large spherical GFBs. Cells accumulating GFBs also contain electron-dense structures that accumulate initially in the ER and which later appear to fuse with the plasma membrane. Structures resembling the GFBs were also observed in the periplasmic space of plasmolized cells. Ultimately, the green fluorescence accumulates in the cell wall, in a process that is insensitive to the Golgi-disturbing agents BFA and monensin. Conclusions Our results suggest the presence of at least two distinct trafficking pathways, one to the cell wall and the other to the vacuole, for different auto-fluorescent compounds induced by the same transcription factor in maize BMS cells. These compartments represent two of the major sites of accumulation of phenolic compounds characteristic of maize cells. The secretion of the green auto-fluorescent compounds occurs by a pathway that does not involve the TGN, suggesting that it is different from the secretion of most proteins, polysaccharides or epicuticular waxes. The

  6. Sub-cellular localisation of a 15N-labelled peptide vector using NanoSIMS imaging

    Science.gov (United States)

    Römer, Winfried; Wu, Ting-Di; Duchambon, Patricia; Amessou, Mohamed; Carrez, Danièle; Johannes, Ludger; Guerquin-Kern, Jean-Luc

    2006-07-01

    Dynamic SIMS imaging is proposed to map sub-cellular distributions of isotopically labelled, exogenous compounds. NanoSIMS imaging allows the characterisation of the intracellular transport pathways of exogenous molecules, including peptide vectors employed in innovative therapies, using stable isotopes as molecular markers to detect the compound of interest. Shiga toxin B-subunit (STxB) was chosen as a representative peptide vector. The recombinant protein ( 15N-STxB) was synthesised in Escherichia coli using 15NH 4Cl as sole nitrogen source resulting in 15N enrichment in the molecule. Using the NanoSIMS 50 ion microprobe (Cameca), different ion species ( 12C 14N -, 12C 15N -, 31P -) originating from the same sputtered micro volume were simultaneously detected. High mass resolving power enabled the discrimination of 12C 15N - from its polyatomic isobars of mass 27. We imaged the membrane binding and internalisation of 15N-STxB in HeLa cells at spatial resolutions of less than 100 nm. Thus, the use of rare stable isotopes like 15N with dynamic SIMS imaging permits sub-cellular detection of isotopically labelled, exogenous molecules and imaging of their transport pathways at high mass and spatial resolution. Application of stable isotopes as markers can replace the large and chemically complex tags used for fluorescence microscopy, without altering the chemical and physical properties of the molecule.

  7. Sub-cellular mRNA localization modulates the regulation of gene expression by small RNAs in bacteria

    Science.gov (United States)

    Teimouri, Hamid; Korkmazhan, Elgin; Stavans, Joel; Levine, Erel

    2017-10-01

    Small non-coding RNAs can exert significant regulatory activity on gene expression in bacteria. In recent years, substantial progress has been made in understanding bacterial gene expression by sRNAs. However, recent findings that demonstrate that families of mRNAs show non-trivial sub-cellular distributions raise the question of how localization may affect the regulatory activity of sRNAs. Here we address this question within a simple mathematical model. We show that the non-uniform spatial distributions of mRNA can alter the threshold-linear response that characterizes sRNAs that act stoichiometrically, and modulate the hierarchy among targets co-regulated by the same sRNA. We also identify conditions where the sub-cellular organization of cofactors in the sRNA pathway can induce spatial heterogeneity on sRNA targets. Our results suggest that under certain conditions, interpretation and modeling of natural and synthetic gene regulatory circuits need to take into account the spatial organization of the transcripts of participating genes.

  8. The in vitro sub-cellular localization and in vivo efficacy of novel chitosan/GMO nanostructures containing paclitaxel.

    Science.gov (United States)

    Trickler, W J; Nagvekar, A A; Dash, A K

    2009-08-01

    To determine the in vitro sub-cellular localization and in vivo efficacy of chitosan/GMO nanostructures containing paclitaxel (PTX) compared to a conventional PTX treatment (Taxol). The sub-cellular localization of coumarin-6 labeled chitosan/GMO nanostructures was determined by confocal microscopy in MDA-MB-231 cells. The antitumor efficacy was evaluated in two separate studies using FOX-Chase (CB17) SCID Female-Mice MDA-MB-231 xenograph model. Treatments consisted of intravenous Taxol or chitosan/GMO nanostructures with or without PTX, local intra-tumor bolus of Taxol or chitosan/GMO nanostructures with or without PTX. The tumor diameter and animal weight was monitored at various intervals. Histopathological changes were evaluated in end-point tumors. The tumor diameter increased at a constant rate for all the groups between days 7-14. After a single intratumoral bolus dose of chitosan/GMO containing PTX showed significant reduction in tumor diameter on day 15 when compared to control, placebo and intravenous PTX administration. The tumor diameter reached a maximal decrease (4-fold) by day 18, and the difference was reduced to approximately 2-fold by day 21. Qualitatively similar results were observed in a separate study containing PTX when administered intravenously. Chitosan/GMO nanostructures containing PTX are safe and effective administered locally or intravenously. Partially supported by DOD Award BC045664.

  9. Differential uptake and oxidative stress response in zebrafish fed a single dose of the principal copper and zinc enriched sub-cellular fractions of Gammarus pulex

    International Nuclear Information System (INIS)

    Khan, Farhan R.; Bury, Nicolas R.; Hogstrand, Christer

    2010-01-01

    The sub-cellular compartmentalisation of trace metals and its effect on trophic transfer and toxicity in the aquatic food chain has been a subject of growing interest. In the present study, the crustacean Gammarus pulex was exposed to either 11 μg Cu l -1 , added solely as the enriched stable isotope 65 Cu, or 660 μg Zn l -1 , radiolabeled with 2MBq 65 Zn, for 16 days. Post-exposure the heat stable cytosol containing metallothionein-like proteins (MTLP) and a combined granular and exoskeletal (MRG + exo) fractions were isolated by differential centrifugation, incorporated into gelatin and fed to zebrafish as a single meal. Assimilation efficiency (AE) and intestinal lipid peroxidation, as malondialdehyde (MDA) were measured. There was a significant difference (p 65 Cu, although the results pointed towards greater bioavailability of the MTLP fraction compared to MRG + exo during the slow elimination phase (24-72 h) these results were not significant (p = 0.155). Neither zinc feed provoked a lipid peroxidation response in the intestinal tissue of zebrafish compared to control fish (gelatin fed), but both 65 Cu labeled feeds did. The greater effect was exerted by the MRG + exo (2.96 ± 0.29 nmol MDA mg protein -1 ) feed which three-fold greater than control (p -1 , p 109 Cd labeled G. pulex fractions were fed to zebrafish. Thus it appears that when a metal (Cu or Cd) has the potential to cause cytotoxicity via lipid peroxidation, a feed consisting of a largely unavailable fraction (MRG + exo) causes a greater intestinal stress response than the more bioavailable (MTLP) feed.

  10. Cell segmentation in time-lapse fluorescence microscopy with temporally varying sub-cellular fusion protein patterns.

    Science.gov (United States)

    Bunyak, Filiz; Palaniappan, Kannappan; Chagin, Vadim; Cardoso, M

    2009-01-01

    Fluorescently tagged proteins such as GFP-PCNA produce rich dynamically varying textural patterns of foci distributed in the nucleus. This enables the behavioral study of sub-cellular structures during different phases of the cell cycle. The varying punctuate patterns of fluorescence, drastic changes in SNR, shape and position during mitosis and abundance of touching cells, however, require more sophisticated algorithms for reliable automatic cell segmentation and lineage analysis. Since the cell nuclei are non-uniform in appearance, a distribution-based modeling of foreground classes is essential. The recently proposed graph partitioning active contours (GPAC) algorithm supports region descriptors and flexible distance metrics. We extend GPAC for fluorescence-based cell segmentation using regional density functions and dramatically improve its efficiency for segmentation from O(N(4)) to O(N(2)), for an image with N(2) pixels, making it practical and scalable for high throughput microscopy imaging studies.

  11. A novel optical microscope for imaging large embryos and tissue volumes with sub-cellular resolution throughout.

    Science.gov (United States)

    McConnell, Gail; Trägårdh, Johanna; Amor, Rumelo; Dempster, John; Reid, Es; Amos, William Bradshaw

    2016-09-23

    Current optical microscope objectives of low magnification have low numerical aperture and therefore have too little depth resolution and discrimination to perform well in confocal and nonlinear microscopy. This is a serious limitation in important areas, including the phenotypic screening of human genes in transgenic mice by study of embryos undergoing advanced organogenesis. We have built an optical lens system for 3D imaging of objects up to 6 mm wide and 3 mm thick with depth resolution of only a few microns instead of the tens of microns currently attained, allowing sub-cellular detail to be resolved throughout the volume. We present this lens, called the Mesolens, with performance data and images from biological specimens including confocal images of whole fixed and intact fluorescently-stained 12.5-day old mouse embryos.

  12. Lipase genes in Mucor circinelloides: identification, sub-cellular location, phylogenetic analysis and expression profiling during growth and lipid accumulation.

    Science.gov (United States)

    Zan, Xinyi; Tang, Xin; Chu, Linfang; Zhao, Lina; Chen, Haiqin; Chen, Yong Q; Chen, Wei; Song, Yuanda

    2016-10-01

    Lipases or triacylglycerol hydrolases are widely spread in nature and are particularly common in the microbial world. The filamentous fungus Mucor circinelloides is a potential lipase producer, as it grows well in triacylglycerol-contained culture media. So far only one lipase from M. circinelloides has been characterized, while the majority of lipases remain unknown in this fungus. In the present study, 47 potential lipase genes in M. circinelloides WJ11 and 30 potential lipase genes in M. circinelloides CBS 277.49 were identified by extensive bioinformatics analysis. An overview of these lipases is presented, including several characteristics, sub-cellular location, phylogenetic analysis and expression profiling of the lipase genes during growth and lipid accumulation. All of these proteins contained the consensus sequence for a classical lipase (GXSXG motif) and were divided into four types including α/β-hydrolase_1, α/β-hydrolase_3, class_3 and GDSL lipase (GDSL) based on gene annotations. Phylogenetic analyses revealed that class_3 family and α/β-hydrolase_3 family were the conserved lipase family in M. circinelloides. Additionally, some lipases also contained a typical acyltransferase motif of H-(X) 4-D, and these lipases may play a dual role in lipid metabolism, catalyzing both lipid hydrolysis and transacylation reactions. The differential expression of all lipase genes were confirmed by quantitative real-time PCR, and the expression profiling were analyzed to predict the possible biological roles of these lipase genes in lipid metabolism in M. circinelloides. We preliminarily hypothesized that lipases may be involved in triacylglycerol degradation, phospholipid synthesis and beta-oxidation. Moreover, the results of sub-cellular localization, the presence of signal peptide and transcriptional analyses of lipase genes indicated that four lipase in WJ11 most likely belong to extracellular lipases with a signal peptide. These findings provide a platform

  13. CHARACTERIZATION OF METAL BENZOTRIAZOLES AND RELATED POLYMERS

    Science.gov (United States)

    Benzotriazole (bta-H) is a well-known corrosion inhibitor for copper, copper-alloy, and other metal surfaces. Typical uses are to deactivate surfaces of computer hard drives and other internal metal computer parts, and for treatment of apparel hardware such as zippers and buttons...

  14. Lysosome-related organelles as mediators of metal homeostasis.

    Science.gov (United States)

    Blaby-Haas, Crysten E; Merchant, Sabeeha S

    2014-10-10

    Metal ion assimilation is essential for all forms of life. However, organisms must properly control the availability of these nutrients within the cell to avoid inactivating proteins by mismetallation. To safeguard against an imbalance between supply and demand in eukaryotes, intracellular compartments contain metal transporters that load and unload metals. Although the vacuoles of Saccharomyces cerevisiae and Arabidopsis thaliana are well established locales for the storage of copper, zinc, iron, and manganese, related compartments are emerging as important mediators of metal homeostasis. Here we describe these compartments and review their metal transporter complement. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Two-Photon Irradiation of an Intracellular Singlet Oxygen Photosensitizer: Achieving Localized Sub-Cellular Excitation in Spatially-Resolved Experiments

    DEFF Research Database (Denmark)

    Pedersen, Brian Wett; Breitenbach, Thomas; Redmond, Robert W.

    2010-01-01

    The response of a given cell to spatially-resolved sub-cellular irradiation of a singlet oxygen photosensitizer (protoporphyrin IX, PpIX) using a focused laser was assessed. In these experiments, incident light was scattered over a volume greater than that defi ned by the dimensions of the laser...

  16. High-resolution sub-cellular imaging by correlative NanoSIMS and electron microscopy of amiodarone internalisation by lung macrophages as evidence for drug-induced phospholipidosis.

    Science.gov (United States)

    Jiang, Haibo; Passarelli, Melissa K; Munro, Peter M G; Kilburn, Matt R; West, Andrew; Dollery, Colin T; Gilmore, Ian S; Rakowska, Paulina D

    2017-01-26

    Correlative NanoSIMS and EM imaging of amiodarone-treated macrophages shows the internalisation of the drug at a sub-cellular level and reveals its accumulation within the lysosomes, providing direct evidence for amiodarone-induced phospholipidosis. Chemical fixation using tannic acid effectively seals cellular membranes aiding intracellular retention of diffusible drugs.

  17. Anks3 alters the sub-cellular localization of the Nek7 kinase

    Energy Technology Data Exchange (ETDEWEB)

    Ramachandran, Haribaskar; Engel, Christina; Müller, Barbara [Renal Division, Department of Medicine, University Freiburg Medical Center, Hugstetter Str. 55, 79106 Freiburg (Germany); Dengjel, Jörn [Department of Dermatology, University Freiburg Medical Center and Center of Biological Systems Analysis, Habsburgerstr. 49, 79104 Freiburg (Germany); Walz, Gerd [Renal Division, Department of Medicine, University Freiburg Medical Center, Hugstetter Str. 55, 79106 Freiburg (Germany); Center for Biological Signaling Studies (BIOSS), Albertstr. 19, 79104 Freiburg (Germany); Yakulov, Toma A., E-mail: toma.antonov.yakulov@uniklinik-freiburg.de [Renal Division, Department of Medicine, University Freiburg Medical Center, Hugstetter Str. 55, 79106 Freiburg (Germany)

    2015-08-28

    Nephronophthisis (NPH) is an autosomal recessive cystic kidney disease, and a frequent cause of end-stage renal failure in children. To date, 17 NPH-associated gene products (NPHPs) have been identified. Most NPHPs participate in large multi-protein complexes that localize to the cilium and/or basal body; however, the precise composition of these complexes and their biological function remain largely unknown. We recently observed that the ankyrin repeat protein Anks3 interacts with the NPH family member Anks6. Both Anks3 and Anks6 form complexes with multiple other NPHPs, suggesting that both proteins function in similar or overlapping signaling pathways. Here, we show that Anks3, but not Anks6 interacted with the NIMA-related kinase Nek7, and was heavily modified in the presence of Nek7, resulting in an approximately 20 kD increase in molecular weight. Although mass spectrometry revealed increased serine and threonine phosphorylation of Anks3 primarily within the N-terminal ankyrin repeats also required for Nek7 interaction, the molecular weight increase occurred even in the presence of a kinase-dead Nek7 mutant, indicating that this modification was not caused by Nek7-dependent Anks3 phosphorylation. Furthermore, the Anks3 modification was specific for Nek7, and did not occur in the presence of Nek8. Importantly, Anks3 retained Nek7 in the cytoplasm, suggesting that, Nek7 triggers the modification of Anks3, which in turn prevents the nuclear localization of Nek7. - Highlights: • Anks3 interacted with Nek7 kinase, and was heavily modified in the presence of Nek7. • Anks3 N-terminal ankyrin repeats, but not SAM domain required for Nek7 interaction. • Nek7 increased Ser/Thr phosphorylation of Anks3 primarily within ankyrin domain. • Interaction with Anks3 led to cytoplasmic retention and nuclear exclusion of Nek7.

  18. The universal relation of galactic chemical evolution: the origin of the mass-metallicity relation

    International Nuclear Information System (INIS)

    Zahid, H. Jabran; Dima, Gabriel I.; Kudritzki, Rolf-Peter; Kewley, Lisa J.; Geller, Margaret J.; Hwang, Ho Seong; Silverman, John D.; Kashino, Daichi

    2014-01-01

    We examine the mass-metallicity relation for z ≲ 1.6. The mass-metallicity relation follows a steep slope with a turnover, or 'knee', at stellar masses around 10 10 M ☉ . At stellar masses higher than the characteristic turnover mass, the mass-metallicity relation flattens as metallicities begin to saturate. We show that the redshift evolution of the mass-metallicity relation depends only on the evolution of the characteristic turnover mass. The relationship between metallicity and the stellar mass normalized to the characteristic turnover mass is independent of redshift. We find that the redshift-independent slope of the mass-metallicity relation is set by the slope of the relationship between gas mass and stellar mass. The turnover in the mass-metallicity relation occurs when the gas-phase oxygen abundance is high enough that the amount of oxygen locked up in low-mass stars is an appreciable fraction of the amount of oxygen produced by massive stars. The characteristic turnover mass is the stellar mass, where the stellar-to-gas mass ratio is unity. Numerical modeling suggests that the relationship between metallicity and the stellar-to-gas mass ratio is a redshift-independent, universal relationship followed by all galaxies as they evolve. The mass-metallicity relation originates from this more fundamental universal relationship between metallicity and the stellar-to-gas mass ratio. We test the validity of this universal metallicity relation in local galaxies where stellar mass, metallicity, and gas mass measurements are available. The data are consistent with a universal metallicity relation. We derive an equation for estimating the hydrogen gas mass from measurements of stellar mass and metallicity valid for z ≲ 1.6 and predict the cosmological evolution of galactic gas masses.

  19. THE METALLICITIES OF LOW STELLAR MASS GALAXIES AND THE SCATTER IN THE MASS-METALLICITY RELATION

    International Nuclear Information System (INIS)

    Zahid, H. J.; Bresolin, F.; Kewley, L. J.; Coil, A. L.; Davé, R.

    2012-01-01

    In this investigation, we quantify the metallicities of low-mass galaxies by constructing the most comprehensive census to date. We use galaxies from the Sloan Digital Sky Survey (SDSS) and DEEP2 survey and estimate metallicities from their optical emission lines. We also use two smaller samples from the literature that have metallicities determined by the direct method using the temperature sensitive [O III]λ4363 line. We examine the scatter in the local mass-metallicity (MZ) relation determined from ∼20,000 star-forming galaxies in the SDSS and show that it is larger at lower stellar masses, consistent with the theoretical scatter in the MZ relation determined from hydrodynamical simulations. We determine a lower limit for the scatter in metallicities of galaxies down to stellar masses of ∼10 7 M ☉ which is only slightly smaller than the expected scatter inferred from the SDSS MZ relation and significantly larger than what has been previously established in the literature. The average metallicity of star-forming galaxies increases with stellar mass. By examining the scatter in the SDSS MZ relation, we show that this is mostly due to the lowest metallicity galaxies. The population of low-mass, metal-rich galaxies have properties that are consistent with previously identified galaxies that may be transitional objects between gas-rich dwarf irregulars and gas-poor dwarf spheroidals and ellipticals.

  20. Drosophila melanogaster Models of Metal-Related Human Diseases and Metal Toxicity.

    Science.gov (United States)

    Calap-Quintana, Pablo; González-Fernández, Javier; Sebastiá-Ortega, Noelia; Llorens, José Vicente; Moltó, María Dolores

    2017-07-06

    Iron, copper and zinc are transition metals essential for life because they are required in a multitude of biological processes. Organisms have evolved to acquire metals from nutrition and to maintain adequate levels of each metal to avoid damaging effects associated with its deficiency, excess or misplacement. Interestingly, the main components of metal homeostatic pathways are conserved, with many orthologues of the human metal-related genes having been identified and characterized in Drosophila melanogaster . Drosophila has gained appreciation as a useful model for studying human diseases, including those caused by mutations in pathways controlling cellular metal homeostasis. Flies have many advantages in the laboratory, such as a short life cycle, easy handling and inexpensive maintenance. Furthermore, they can be raised in a large number. In addition, flies are greatly appreciated because they offer a considerable number of genetic tools to address some of the unresolved questions concerning disease pathology, which in turn could contribute to our understanding of the metal metabolism and homeostasis. This review recapitulates the metabolism of the principal transition metals, namely iron, zinc and copper, in Drosophila and the utility of this organism as an experimental model to explore the role of metal dyshomeostasis in different human diseases. Finally, a summary of the contribution of Drosophila as a model for testing metal toxicity is provided.

  1. Similar star formation rate and metallicity variability time-scales drive the fundamental metallicity relation

    Science.gov (United States)

    Torrey, Paul; Vogelsberger, Mark; Hernquist, Lars; McKinnon, Ryan; Marinacci, Federico; Simcoe, Robert A.; Springel, Volker; Pillepich, Annalisa; Naiman, Jill; Pakmor, Rüdiger; Weinberger, Rainer; Nelson, Dylan; Genel, Shy

    2018-06-01

    The fundamental metallicity relation (FMR) is a postulated correlation between galaxy stellar mass, star formation rate (SFR), and gas-phase metallicity. At its core, this relation posits that offsets from the mass-metallicity relation (MZR) at a fixed stellar mass are correlated with galactic SFR. In this Letter, we use hydrodynamical simulations to quantify the time-scales over which populations of galaxies oscillate about the average SFR and metallicity values at fixed stellar mass. We find that Illustris and IllustrisTNG predict that galaxy offsets from the star formation main sequence and MZR oscillate over similar time-scales, are often anticorrelated in their evolution, evolve with the halo dynamical time, and produce a pronounced FMR. Our models indicate that galaxies oscillate about equilibrium SFR and metallicity values - set by the galaxy's stellar mass - and that SFR and metallicity offsets evolve in an anticorrelated fashion. This anticorrelated variability of the metallicity and SFR offsets drives the existence of the FMR in our models. In contrast to Illustris and IllustrisTNG, we speculate that the SFR and metallicity evolution tracks may become decoupled in galaxy formation models dominated by feedback-driven globally bursty SFR histories, which could weaken the FMR residual correlation strength. This opens the possibility of discriminating between bursty and non-bursty feedback models based on the strength and persistence of the FMR - especially at high redshift.

  2. HIDE-AND-SEEK WITH THE FUNDAMENTAL METALLICITY RELATION

    Energy Technology Data Exchange (ETDEWEB)

    Kashino, D. [Division of Particle and Astrophysical Science, Graduate School of Science, Nagoya University, Nagoya, 464-8602 (Japan); Renzini, A. [INAF Osservatorio Astronomico di Padova, vicolo dell’Osservatorio 5, I-35122 Padova (Italy); Silverman, J. D. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, the University of Tokyo, Kashiwanoha, Kashiwa, 277-8583 (Japan); Daddi, E., E-mail: daichi@nagoya-u.jp [Laboratoire AIM-Paris-Saclay, CEA/DSM-CNRS-Université Paris Diderot, Irfu/CEA-Saclay, Service d’Astrophysique, F-91191 Gif-sur-Yvette (France)

    2016-06-01

    We use ∼83,000 star-forming galaxies at 0.04 < z < 0.3 from the Sloan Digital Sky Survey to study the so-called fundamental metallicity relation (FMR) and report on the disappearance of its anti-correlation between metallicity and star formation rate (SFR) when using the new metallicity indicator recently proposed by Dopita et al. In this calibration, metallicity is primarily sensitive to the emission line ratio [N ii] λ 6584/[S ii] λλ 6717, 6731 that is insensitive to dilution by pristine infalling gas that may drive the FMR anti-correlation with SFR. Therefore, we conclude that the apparent disappearance of the FMR (using this new metallicity indicator) does not rule out its existence.

  3. Cloning, characterization and sub-cellular localization of gamma subunit of T-complex protein-1 (chaperonin) from Leishmania donovani

    Energy Technology Data Exchange (ETDEWEB)

    Bhaskar,; Kumari, Neeti [Division of Biochemistry, CSIR-Central Drug Research Institute, Chattar Manzil Palace, PO Box 173, Lucknow (India); Goyal, Neena, E-mail: neenacdri@yahoo.com [Division of Biochemistry, CSIR-Central Drug Research Institute, Chattar Manzil Palace, PO Box 173, Lucknow (India)

    2012-12-07

    Highlights: Black-Right-Pointing-Pointer The study presents cloning and characterization of TCP1{gamma} gene from L. donovani. Black-Right-Pointing-Pointer TCP1{gamma} is a subunit of T-complex protein-1 (TCP1), a chaperonin class of protein. Black-Right-Pointing-Pointer LdTCP{gamma} exhibited differential expression in different stages of promastigotes. Black-Right-Pointing-Pointer LdTCP{gamma} co-localized with actin, a cytoskeleton protein. Black-Right-Pointing-Pointer The data suggests that this gene may have a role in differentiation/biogenesis. Black-Right-Pointing-Pointer First report on this chapronin in Leishmania. -- Abstract: T-complex protein-1 (TCP1) complex, a chaperonin class of protein, ubiquitous in all genera of life, is involved in intracellular assembly and folding of various proteins. The gamma subunit of TCP1 complex (TCP1{gamma}), plays a pivotal role in the folding and assembly of cytoskeleton protein(s) as an individual or complexed with other subunits. Here, we report for the first time cloning, characterization and expression of the TCP1{gamma} of Leishmania donovani (LdTCP1{gamma}), the causative agent of Indian Kala-azar. Primary sequence analysis of LdTCP1{gamma} revealed the presence of all the characteristic features of TCP1{gamma}. However, leishmanial TCP1{gamma} represents a distinct kinetoplastid group, clustered in a separate branch of the phylogenic tree. LdTCP1{gamma} exhibited differential expression in different stages of promastigotes. The non-dividing stationary phase promastigotes exhibited 2.5-fold less expression of LdTCP1{gamma} as compared to rapidly dividing log phase parasites. The sub-cellular distribution of LdTCP1{gamma} was studied in log phase promastigotes by employing indirect immunofluorescence microscopy. The protein was present not only in cytoplasm but it was also localized in nucleus, peri-nuclear region, flagella, flagellar pocket and apical region. Co-localization of LdTCP1{gamma} with actin suggests

  4. Cloning, characterization and sub-cellular localization of gamma subunit of T-complex protein-1 (chaperonin) from Leishmania donovani

    International Nuclear Information System (INIS)

    Bhaskar,; Kumari, Neeti; Goyal, Neena

    2012-01-01

    Highlights: ► The study presents cloning and characterization of TCP1γ gene from L. donovani. ► TCP1γ is a subunit of T-complex protein-1 (TCP1), a chaperonin class of protein. ► LdTCPγ exhibited differential expression in different stages of promastigotes. ► LdTCPγ co-localized with actin, a cytoskeleton protein. ► The data suggests that this gene may have a role in differentiation/biogenesis. ► First report on this chapronin in Leishmania. -- Abstract: T-complex protein-1 (TCP1) complex, a chaperonin class of protein, ubiquitous in all genera of life, is involved in intracellular assembly and folding of various proteins. The gamma subunit of TCP1 complex (TCP1γ), plays a pivotal role in the folding and assembly of cytoskeleton protein(s) as an individual or complexed with other subunits. Here, we report for the first time cloning, characterization and expression of the TCP1γ of Leishmania donovani (LdTCP1γ), the causative agent of Indian Kala-azar. Primary sequence analysis of LdTCP1γ revealed the presence of all the characteristic features of TCP1γ. However, leishmanial TCP1γ represents a distinct kinetoplastid group, clustered in a separate branch of the phylogenic tree. LdTCP1γ exhibited differential expression in different stages of promastigotes. The non-dividing stationary phase promastigotes exhibited 2.5-fold less expression of LdTCP1γ as compared to rapidly dividing log phase parasites. The sub-cellular distribution of LdTCP1γ was studied in log phase promastigotes by employing indirect immunofluorescence microscopy. The protein was present not only in cytoplasm but it was also localized in nucleus, peri-nuclear region, flagella, flagellar pocket and apical region. Co-localization of LdTCP1γ with actin suggests that, this gene may have a role in maintaining the structural dynamics of cytoskeleton of parasite.

  5. ORIGIN OF THE GALAXY MASS-METALLICITY-STAR FORMATION RELATION

    International Nuclear Information System (INIS)

    Harwit, Martin; Brisbin, Drew

    2015-01-01

    We describe an equilibrium model that links the metallicity of low-redshift galaxies to stellar evolution models. It enables the testing of different stellar initial mass functions and metal yields against observed galaxy metallicities. We show that the metallicities of more than 80,000 Sloan Digital Sky Survey galaxies in the low-redshift range 0.07 ≤ z ≤ 0.3 considerably constrain stellar evolution models that simultaneously relate galaxy stellar mass, metallicity, and star formation rates to the infall rate of low-metallicity extragalactic gas and outflow of enriched matter. A feature of our model is that it encompasses both the active star forming phases of a galaxy and epochs during which the same galaxy may lie fallow. We show that the galaxy mass-metallicity-star formation relation can be traced to infall of extragalactic gas mixing with native gas from host galaxies to form stars of observed metallicities, the most massive of which eject oxygen into extragalactic space. Most consequential among our findings is that, on average, extragalactic infall accounts for one half of the gas required for star formation, a ratio that is remarkably constant across galaxies with stellar masses ranging at least from M* = 2 × 10 9 to 6 × 10 10 M ☉ . This leads us to propose that star formation is initiated when extragalactic infall roughly doubles the mass of marginally stable interstellar clouds. The processes described may also account quantitatively for the metallicity of extragalactic space, though to check this the fraction of extragalactic baryons will need to be more firmly established

  6. ORIGIN OF THE GALAXY MASS-METALLICITY-STAR FORMATION RELATION

    Energy Technology Data Exchange (ETDEWEB)

    Harwit, Martin; Brisbin, Drew, E-mail: harwit@verizon.net [Center for Radiophysics and Space Research, Cornell University, Ithaca, NY 14853 (United States)

    2015-02-20

    We describe an equilibrium model that links the metallicity of low-redshift galaxies to stellar evolution models. It enables the testing of different stellar initial mass functions and metal yields against observed galaxy metallicities. We show that the metallicities of more than 80,000 Sloan Digital Sky Survey galaxies in the low-redshift range 0.07 ≤ z ≤ 0.3 considerably constrain stellar evolution models that simultaneously relate galaxy stellar mass, metallicity, and star formation rates to the infall rate of low-metallicity extragalactic gas and outflow of enriched matter. A feature of our model is that it encompasses both the active star forming phases of a galaxy and epochs during which the same galaxy may lie fallow. We show that the galaxy mass-metallicity-star formation relation can be traced to infall of extragalactic gas mixing with native gas from host galaxies to form stars of observed metallicities, the most massive of which eject oxygen into extragalactic space. Most consequential among our findings is that, on average, extragalactic infall accounts for one half of the gas required for star formation, a ratio that is remarkably constant across galaxies with stellar masses ranging at least from M* = 2 × 10{sup 9} to 6 × 10{sup 10} M {sub ☉}. This leads us to propose that star formation is initiated when extragalactic infall roughly doubles the mass of marginally stable interstellar clouds. The processes described may also account quantitatively for the metallicity of extragalactic space, though to check this the fraction of extragalactic baryons will need to be more firmly established.

  7. Making Sense of Metal Allergy and Hypersensitivity to Metallic Implants in Relation to Hand Surgery.

    Science.gov (United States)

    Christensen, Thomas J; Samant, Shefali A; Shin, Alexander Y

    2017-09-01

    All metals implanted into a biological system undergo some degree of corrosion depending upon its composition. The electrochemical process of corrosion produces free metal ions, which may activate the host's immune system through a variety of mechanisms. Whereas dermal metal hypersensitivity is common, affecting 10% to 15% of the population, the immune reaction from implanted metals is much less common (allergy and hypersensitivity producing a multitude of patient symptoms. Superficial symptoms may be mild to severe forms of dermatitis, urticaria, pruritus, and vasculitis, whereas deep sequelae include metallosis-related pseudotumor, implant loosening, and joint stiffness. Currently, there are clinical tests to evaluate patients for metal hypersensitivity, but there is little agreement regarding the ideal timing and clinical situation prompting the work-up of a patient for a metal allergy or hypersensitivity. An understanding of the epidemiology, etiology, basic science, diagnostic testing, and treatment of patients with suspected metal allergy, as it pertains to the current literature, will aid orthopedic and plastic surgeons of all subspecialties in the management of patients requiring metallic implants. Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  8. Creep mechanisms and constitutive relations in pure metals

    International Nuclear Information System (INIS)

    Nix, W.D.

    1979-01-01

    The mechanisms of creep of pure metals is briefly reviewed and divided into two parts: steady state flow mechanisms, and non-steady state flow mechanisms and constitutive relations. Creep by diffusional flow is now reasonably well understood, with theory and experiment in good agreement. The closely related phenomenon of Harper--Dorn creep can also be understood in terms of diffusion between dislocations. Power law creep involves the climb of edge disloctions controlled by lattice self diffusion. Theoretical treatments of this process invariably give a power law exponent of 3. This natural creep law is compared with the data for FCC and BCC metals. It is suggested that diffusion controlled climb is the controlling process in BCC metals at very high temperatures. Stacking fault energy effects may preclude the possibility that creep is controlled entirely by lattice self diffusion in some FCC metals. The subject of power law breakdown is presented as a natural consequence of the transition to low temperature flow phenomena. The role of core diffusion in this transition is briefly discussed. The mechanisms are presented by which pure metals creep at elevated temperatures. While most of this review deals with the mechanisms of steady state flow, some discussion is devoted to creep flow under non-steady state conditions. This topic is discussed in connection with the development of constitutive equations for describing plastic flow in metals

  9. CE of phytosiderophores and related metal species in plants.

    Science.gov (United States)

    Xuan, Yue; Scheuermann, Enrico B; Meda, Anderson R; Jacob, Peter; von Wirén, Nicolaus; Weber, Günther

    2007-10-01

    Phytosiderophores (PS) and the closely related substance nicotianamine (NA) are key substances in metal uptake into graminaceous plants. Here, the CE separation of these substances and related metal species is demonstrated. In particular, the three PS 2'-deoxymugineic acid (DMA), mugineic acid (MA), and 3-epi-hydroxymugineic acid (epi-HMA), and NA, are separated using MES/Tris buffer at pH 7.3. Moreover, three Fe(III) species of the different PS are separated without any stability problems, which are often present in chromatographic analyses. Also divalent metal species of Cu, Ni, and Zn with the ligands DMA and NA are separated with the same method. By using a special, zwitterionic CE capillary, even the separation of two isomeric Fe(III) chelates with the ligand ethylenediamine-N,N'-bis(o-hydroxyphenyl)acetic acid (EDDHA) is possible (i.e., meso-Fe(III)-EDDHA and rac-Fe(III)-EDDHA), and for fast separations of NA and respective divalent and trivalent metal species, a polymer CE microchip with suppressed EOF is described. The proposed CE method is applicable to real plant samples, and enables to detect changes of metal species (Cu-DMA, Ni-NA), which are directly correlated to biological processes.

  10. Chelation in metal intoxication. V. Lowering of manganese content in poisoned rat organs

    Energy Technology Data Exchange (ETDEWEB)

    Tandon, S K; Mathur, A K

    1976-01-01

    Metal chelation has been considered useful in the management of manganese poisoning to a considerable extent. Our own studies in this direction have shown that some polyaminocarboxylic acids and a few amino acids are effective in not only removing manganese from the vital organs of experimentally poisoned animals but also in restoring certain metal induced biochemical and histological changes in such organs. Further, the success of p-aminosalicylic acid (PAS), a chemotherapeutic agent for tuberculosis, in manganese mobilization has led us to examine some other structurally related compounds together with a few other possible metal binding agents for their ability to remove excess metal from the organs, their sub-cellular fractions and blood cells of manganese administered rats and to investigate if there exists any relationship between the structure of such compounds and their metal mobilizing capacity. The present communication deals with the results of these investigations.

  11. Sub-cellular localisation studies may spuriously detect the Yes-associated protein, YAP, in nucleoli leading to potentially invalid conclusions of its function.

    Science.gov (United States)

    Finch, Megan L; Passman, Adam M; Strauss, Robyn P; Yeoh, George C; Callus, Bernard A

    2015-01-01

    The Yes-associated protein (YAP) is a potent transcriptional co-activator that functions as a nuclear effector of the Hippo signaling pathway. YAP is oncogenic and its activity is linked to its cellular abundance and nuclear localisation. Activation of the Hippo pathway restricts YAP nuclear entry via its phosphorylation by Lats kinases and consequent cytoplasmic retention bound to 14-3-3 proteins. We examined YAP expression in liver progenitor cells (LPCs) and surprisingly found that transformed LPCs did not show an increase in YAP abundance compared to the non-transformed LPCs from which they were derived. We then sought to ascertain whether nuclear YAP was more abundant in transformed LPCs. We used an antibody that we confirmed was specific for YAP by immunoblotting to determine YAP's sub-cellular localisation by immunofluorescence. This antibody showed diffuse staining for YAP within the cytosol and nuclei, but, noticeably, it showed intense staining of the nucleoli of LPCs. This staining was non-specific, as shRNA treatment of cells abolished YAP expression to undetectable levels by Western blot yet the nucleolar staining remained. Similar spurious YAP nucleolar staining was also seen in mouse embryonic fibroblasts and mouse liver tissue, indicating that this antibody is unsuitable for immunological applications to determine YAP sub-cellular localisation in mouse cells or tissues. Interestingly nucleolar staining was not evident in D645 cells suggesting the antibody may be suitable for use in human cells. Given the large body of published work on YAP in recent years, many of which utilise this antibody, this study raises concerns regarding its use for determining sub-cellular localisation. From a broader perspective, it serves as a timely reminder of the need to perform appropriate controls to ensure the validity of published data.

  12. Dynamic compressive constitutive relation and shearing instability of metallic neodymium

    International Nuclear Information System (INIS)

    Wang Huanran; Cai Canyuan; Chen Danian; Ma Dongfang; Hou Yanjun; Wu Shanxing

    2011-01-01

    Highlights: → Dynamic constitutive relation of Nd was determined in first compression of SHPB. → Deformation of Nd in multi-compression of SHPB were recorded by high-speed camera. → Constitutive relation of Nd was adjusted in modeling large deformation of Nd. → Results of SDDM investigation of recovered Nd specimens showed shearing fracture. → Shearing instability of Nd was estimated with constitutive relation. - Abstract: Based on static tests on MTS and dynamic tests on split Hopkinson pressure bar (SHPB) during the first loading, this study determined the dynamic compressive constitutive relation of metallic Nd. Based on large deformations of metallic Nd specimens generated by the multi-compressive loadings during SHPB tests, and recorded by a high-speed camera, the results of numerical simulations for SHPB test processes were used to extend the determined constitutive relation from small strain to large strain. The shearing instability strain in dynamic compressive deformations of metallic Nd was estimated with the extended constitutive relation according to the criterion given by Batra and Wei, and was compared with the average strain of recovered specimens.

  13. Rare metal granites and related rocks of the Ukrainian shield

    Directory of Open Access Journals (Sweden)

    Esipchuk, K.Ye.

    1993-12-01

    Full Text Available Two rare metal leucocratic granites, Perga and Kamennaya complexes, can be distinquished on the Ukrainian shield. The Perga complex consists of medium- and coarse grained, mainly porphyric, biotite, riebeckite and aegirine granites, granite porphyries, microclinites and albitites with rare metal mineralization (genthelvite, phenacite, tantalite, cassiterite and wolframite etc.. Granites from several stocks (up to 30 km2 in the northwestern part of the shield, situated along the fracture zone, restricted the large Korosten pluton of rapakivi granites to the northwest. The age of these granites (Pb-Pb and U-Pb methods on zircon and monazite practically coincide with the age of rapakivi granites being 1750 Ma. Within the Korosten complex of rapakivi granites we consider that zinnwaldite granites, which are characterized by fluorite and topazine mineralization, represent the final phase of pluton. These granites differ from the Perga ones by their low content of rare metals. The Kamennaya Mogila complex lies in the southeastern part of the Ukrainian shield. It consists of biotite and muscovite-biotite, medium- and coarse-grained (also porphyric, and occasionally greisining granites with rare metal mineralization (cassiterite, columbite, molybdenite, wolframite and beryl. Granites form several stocks (5-30 km2 situated 10-30 km to the west-northwest of the South-Kalchik gabbro-syenite-granite pluton. Granitoids in both of these complexes have similar isotopic ages (1800 Ma. Leucocratic subalkaline granites (the Novoyanisol type are known within the pluton itself, occupying an intermediate position between the above mentioned in terms of mineral and geochemical composition. The gabbro-syenite-granite formation of the Nearazov region has a substantial similarity to the anorthosite-rapakivi-granite formation. In this respect the relation of each of them to rare metal granites is rather remarkable. This relation is, most probably, not only spatial, but

  14. Interaction of HSP20 with a viral RdRp changes its sub-cellular localization and distribution pattern in plants.

    Science.gov (United States)

    Li, Jing; Xiang, Cong-Ying; Yang, Jian; Chen, Jian-Ping; Zhang, Heng-Mu

    2015-09-11

    Small heat shock proteins (sHSPs) perform a fundamental role in protecting cells against a wide array of stresses but their biological function during viral infection remains unknown. Rice stripe virus (RSV) causes a severe disease of rice in Eastern Asia. OsHSP20 and its homologue (NbHSP20) were used as baits in yeast two-hybrid (YTH) assays to screen an RSV cDNA library and were found to interact with the viral RNA-dependent RNA polymerase (RdRp) of RSV. Interactions were confirmed by pull-down and BiFC assays. Further analysis showed that the N-terminus (residues 1-296) of the RdRp was crucial for the interaction between the HSP20s and viral RdRp and responsible for the alteration of the sub-cellular localization and distribution pattern of HSP20s in protoplasts of rice and epidermal cells of Nicotiana benthamiana. This is the first report that a plant virus or a viral protein alters the expression pattern or sub-cellular distribution of sHSPs.

  15. Implications of the dwarfs spheroidal galaxy mass-metallicity relation

    International Nuclear Information System (INIS)

    Smith, G.H.

    1985-01-01

    The properties of the mass-metallicity relation among dwarf spheroidal galaxies are discussed in terms of a model which assumes that the internal chemical evolution of the dwarf spheroidals was promoted by supernova activity. The model can be used to explain the observed dwarf spheroidal mass-metallicity relation assuming the present mass of these systems M sub s is proportional to their initial masses M as M sub s varies according to a power-law index of exp 7/4. It is inferred from the power-law dependence of M on the proto-cloud radius that the most massive dwarf spheroids were formed from the densest clouds. The observed slope of the mass-metallicity relation for dwarf spheroidal galaxies is found to be significantly different from theoretical estimates of this slope for elliptical galaxies. It is suggested that the difference may imply that spheroidal dwarfs and elliptical galaxies had different formation histories, confirming Kormendy's (1985) observations of differences in the brightness and luminosity trends. 54 references

  16. Toxicity of selenite in the unicellular green alga Chlamydomonas reinhardtii: Comparison between effects at the population and sub-cellular level

    International Nuclear Information System (INIS)

    Morlon, Helene; Fortin, Claude; Floriani, Magali; Adam, Christelle; Garnier-Laplace, Jacqueline; Boudou, Alain

    2005-01-01

    The toxicity of selenium in aquatic ecosystems is mainly linked to its uptake and biotransformation by micro-organisms, and its subsequent transfer upwards into the food chain. Thus, organisms at low trophic level, such as algae, play a crucial role. The aim of our study was to investigate the biological effects of selenite on Chlamydomonas reinhardtii, both at the sub-cellular level (effect on ultrastructure) and at the population level (effect on growth). The cells were grown under batch culture conditions in well-defined media and exposed to waterborne selenite at concentrations up to 500 μM; i.e. up to lethal conditions. Based on the relationship between Se concentration and cell density achieved after a 96 h exposure period, an EC 50 of 80 μM with a 95% confidence interval ranging between 64 and 98 μM was derived. No adaptation mechanisms were observed: the same toxicity was quantified for algae pre-contaminated with Se. The inhibition of growth was linked to impairments observed at the sub-cellular level. The intensity of the ultrastructural damages caused by selenite exposure depended on the level and duration of exposure. Observations by TEM suggested chloroplasts as the first target of selenite cytotoxicity, with effects on the stroma, thylakoids and pyrenoids. At higher concentrations, we could observe an increase in the number and volume of starch grains. For cells collected at 96 h, electron-dense granules were observed. Energy-dispersive X-ray microanalysis revealed that these granules contained selenium and were also rich in calcium and phosphorus. This study confirms that the direct toxicity of selenite on the phytoplankton biomass is not likely to take place at concentrations found in the environment. At higher concentrations, the link between effects at the sub-cellular and population levels, the over-accumulation of starch, and the formation of dense granules containing selenium are reported for the first time in the literature for a

  17. A celiac cellular phenotype, with altered LPP sub-cellular distribution, is inducible in controls by the toxic gliadin peptide P31-43.

    Directory of Open Access Journals (Sweden)

    Merlin Nanayakkara

    Full Text Available Celiac disease (CD is a frequent inflammatory intestinal disease, with a genetic background, caused by gliadin-containing food. Undigested gliadin peptides P31-43 and P57-68 induce innate and adaptive T cell-mediated immune responses, respectively. Alterations in the cell shape and actin cytoskeleton are present in celiac enterocytes, and gliadin peptides induce actin rearrangements in both the CD mucosa and cell lines. Cell shape is maintained by the actin cytoskeleton and focal adhesions, sites of membrane attachment to the extracellular matrix. The locus of the human Lipoma Preferred Partner (LPP gene was identified as strongly associated with CD using genome-wide association studies (GWAS. The LPP protein plays an important role in focal adhesion architecture and acts as a transcription factor in the nucleus. In this study, we examined the hypothesis that a constitutive alteration of the cell shape and the cytoskeleton, involving LPP, occurs in a cell compartment far from the main inflammation site in CD fibroblasts from skin explants. We analyzed the cell shape, actin organization, focal adhesion number, focal adhesion proteins, LPP sub-cellular distribution and adhesion to fibronectin of fibroblasts obtained from CD patients on a Gluten-Free Diet (GFD and controls, without and with treatment with A-gliadin peptide P31-43. We observed a "CD cellular phenotype" in these fibroblasts, characterized by an altered cell shape and actin organization, increased number of focal adhesions, and altered intracellular LPP protein distribution. The treatment of controls fibroblasts with gliadin peptide P31-43 mimics the CD cellular phenotype regarding the cell shape, adhesion capacity, focal adhesion number and LPP sub-cellular distribution, suggesting a close association between these alterations and CD pathogenesis.

  18. TSCA Chemical Data Reporting Fact Sheet: Reporting Manufactured Chemical Substances from Metal Mining and Related Activities

    Science.gov (United States)

    This fact sheet provides guidance on the Chemical Data Reporting (CDR) rule requirements related to the reporting of mined metals, intermediates, and byproducts manufactured during metal mining and related activities.

  19. Mass and metallicity scaling relations of high-redshift star-forming galaxies selected by GRBs

    DEFF Research Database (Denmark)

    Arabsalmani, M.; Møller, P.; Perley, D.~A.

    2018-01-01

    -metallicity relation of the general population. It is hard to decide whether this relatively small offset is due to systematic effects or the intrinsic nature of GRB hosts. We also investigate the possibility of using absorption-line metallicity measurements of GRB hosts to study the mass-metallicity relation at high...

  20. Distributions and natural levels of related metals in a trophic pathway

    International Nuclear Information System (INIS)

    Lemons, J.D.

    1976-06-01

    The first objective was to test the hypothesis that metal distributions and trends in organisms are, in part, a function of metal positions in the periodic table in unpolluted ecosystems. The data have shown that large soil crustal abundance differences of related elements (e.g. alkali metals) are proportionately approximated in higher organisms. Concentration factors for related nutritious and nonessential and toxic metals were determined along a trophic pathway. When the concentration factors were reported as the concentration of a particular metal by itself, all metal concentrations increased along the trophic pathway. The second objective of this study was to test the hypothesis that distributions and natural levels of chemically related nonessential and toxic metals can better be known when the metals are reported as a ratio, in ash, of the nonessential or toxic metal to its chemically related nutritious metal (e.g. strontium/calcium) as the metals are transferred through trophic pathways. The data have shown that when this method of reporting metal abundances in trophic levels is used, nonessential and toxic metals are discriminated against, relative to their chemically related nutritious metal, as the metals are transferred through the trophic pathway levels. The third objective was designed to test the hypothesis that surface deposition of toxic metals upon plants influences the trends of metal abundances through trophic pathways. This study indicates that metal pollution in the form of deposition upon plant surfaces bypasses the discrimination mechanisms in plants, and consequently elevates the total body burden in herbivores. It is likely that there is no herbivore defense for this type of metal exposure, because herbivores have probably come to rely, in part, upon the discriminatory mechanism of plants throughout the course of evolutionary history to keep toxic metal burdens low

  1. Abductor dysfunction and related sciatic nerve palsy, a new complication of metal-on-metal arthroplasty.

    Science.gov (United States)

    Beaver, Walter B; Fehring, Thomas K

    2012-08-01

    The optimal bearing for use in young patients with hip arthritis remains elusive. Current options include metal-on-cross-linked polyethylene, ceramic-on-cross-linked polyethylene, ceramic on ceramic, and metal on metal. Each of these bearing couples has advantages and disadvantages. Metal-on-metal designs allow the use of large heads that decrease impingement and improve stability. This fact has made this bearing an attractive option for surgeons and patients alike. This case report will illustrate a severe adverse reaction to metal debris with necrosis of soft tissues and subsequent damage to the sciatic nerve. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Fe-S cluster coordination of the chromokinesin KIF4A alters its sub-cellular localization during mitosis.

    Science.gov (United States)

    Ben-Shimon, Lilach; Paul, Viktoria D; David-Kadoch, Galit; Volpe, Marina; Stümpfig, Martin; Bill, Eckhard; Mühlenhoff, Ulrich; Lill, Roland; Ben-Aroya, Shay

    2018-05-30

    Fe-S clusters act as co-factors of proteins with diverse functions, e.g. in DNA repair. Down-regulation of the cytosolic iron-sulfur protein assembly (CIA) machinery promotes genomic instability by the inactivation of multiple DNA repair pathways. Furthermore, CIA deficiencies are associated with so far unexplained mitotic defects. Here, we show that CIA2B and MMS19, constituents of the CIA targeting complex involved in facilitating Fe-S cluster insertion into cytosolic and nuclear target proteins, co-localize with components of the mitotic machinery. Down-regulation of CIA2B and MMS19 impairs the mitotic cycle. We identify the chromokinesin KIF4A as a mitotic component involved in these effects. KIF4A binds a Fe-S cluster in vitro through its conserved cysteine-rich domain. We demonstrate in vivo that this domain is required for the mitosis-related KIF4A localization and for the mitotic defects associated with KIF4A knockout. KIF4A is the first identified mitotic component carrying such a post-translational modification. These findings suggest that the lack of Fe-S clusters in KIF4A upon down-regulation of the CIA targeting complex contributes to the mitotic defects. © 2018. Published by The Company of Biologists Ltd.

  3. Precision automation of cell type classification and sub-cellular fluorescence quantification from laser scanning confocal images

    Directory of Open Access Journals (Sweden)

    Hardy Craig Hall

    2016-02-01

    Full Text Available While novel whole-plant phenotyping technologies have been successfully implemented into functional genomics and breeding programs, the potential of automated phenotyping with cellular resolution is largely unexploited. Laser scanning confocal microscopy has the potential to close this gap by providing spatially highly resolved images containing anatomic as well as chemical information on a subcellular basis. However, in the absence of automated methods, the assessment of the spatial patterns and abundance of fluorescent markers with subcellular resolution is still largely qualitative and time-consuming. Recent advances in image acquisition and analysis, coupled with improvements in microprocessor performance, have brought such automated methods within reach, so that information from thousands of cells per image for hundreds of images may be derived in an experimentally convenient time-frame. Here, we present a MATLAB-based analytical pipeline to 1 segment radial plant organs into individual cells, 2 classify cells into cell type categories based upon random forest classification, 3 divide each cell into sub-regions, and 4 quantify fluorescence intensity to a subcellular degree of precision for a separate fluorescence channel. In this research advance, we demonstrate the precision of this analytical process for the relatively complex tissues of Arabidopsis hypocotyls at various stages of development. High speed and robustness make our approach suitable for phenotyping of large collections of stem-like material and other tissue types.

  4. Relation between heavy metals level in soil and some economic ...

    African Journals Online (AJOL)

    Ekpo

    Soil sample with the depth of (0-15cm), cassava leaves and, ... and P111. The high concentrations of trace metals recorded in the leaves of the plant species may be due to ... average temperature is between 250C and 360C ... the traditional land tenure system and the major crops ..... Historical records of metals pollution.

  5. Method for extracting copper, silver and related metals

    Science.gov (United States)

    Moyer, Bruce A.; McDowell, W. J.

    1990-01-01

    A process for selectively extracting precious metals such as silver and gold concurrent with copper extraction from aqueous solutions containing the same. The process utilizes tetrathiamacrocycles and high molecular weight organic acids that exhibit a synergistic relationship when complexing with certain metal ions thereby removing them from ore leach solutions.

  6. Methods for recovering metals from electronic waste, and related systems

    Science.gov (United States)

    Lister, Tedd E; Parkman, Jacob A; Diaz Aldana, Luis A; Clark, Gemma; Dufek, Eric J; Keller, Philip

    2017-10-03

    A method of recovering metals from electronic waste comprises providing a powder comprising electronic waste in at least a first reactor and a second reactor and providing an electrolyte comprising at least ferric ions in an electrochemical cell in fluid communication with the first reactor and the second reactor. The method further includes contacting the powders within the first reactor and the second reactor with the electrolyte to dissolve at least one base metal from each reactor into the electrolyte and reduce at least some of the ferric ions to ferrous ions. The ferrous ions are oxidized at an anode of the electrochemical cell to regenerate the ferric ions. The powder within the second reactor comprises a higher weight percent of the at least one base metal than the powder in the first reactor. Additional methods of recovering metals from electronic waste are also described, as well as an apparatus of recovering metals from electronic waste.

  7. THE MASS-METALLICITY RELATION OF GLOBULAR CLUSTERS IN THE CONTEXT OF NONLINEAR COLOR-METALLICTY RELATIONS

    International Nuclear Information System (INIS)

    Blakeslee, John P.; Cantiello, Michele; Peng, Eric W.

    2010-01-01

    Two recent empirical developments in the study of extragalactic globular cluster (GC) populations are the color-magnitude relation of the blue GCs (the 'blue tilt') and the nonlinearity of the dependence of optical GC colors on metallicity. The color-magnitude relation, interpreted as a mass-metallicity relation, is thought to be a consequence of self-enrichment. Nonlinear color-metallicity relations have been shown to produce bimodal color distributions from unimodal metallicity distributions. We simulate GC populations including both a mass-metallicity scaling relation and nonlinear color-metallicity relations motivated by theory and observations. Depending on the assumed range of metallicities and the width of the GC luminosity function (GCLF), we find that the simulated populations can have bimodal color distributions with a 'blue tilt' similar to observations, even though the metallicity distribution appears unimodal. The models that produce these features have the relatively high mean GC metallicities and nearly equal blue and red peaks characteristic of giant elliptical galaxies. The blue tilt is less apparent in the models with metallicities typical of dwarf ellipticals; the narrower GCLF in these galaxies has an even bigger effect in reducing the significance of their color-magnitude slopes. We critically examine the evidence for nonlinearity versus bimodal metallicities as explanations for the characteristic double-peaked color histograms of giant ellipticals and conclude that the question remains open. We discuss the prospects for further theoretical and observational progress in constraining the models presented here and for uncovering the true metallicity distributions of extragalactic GC systems.

  8. Improvements in or relating to surface treatment of metals

    International Nuclear Information System (INIS)

    Dearnaley, G.; Hartley, N.E.W.

    1975-01-01

    A method is described for surface treating metals so as to reduce their coefficients of friction. The metal is subjected to bombardment by a beam of ions of dry lubricant material, or material that forms a dry lubricant. The ions should have energies sufficient to cause them to be implanted into the surface region of the metal. The metal may be heated to facilitate assimilation of the ions, and implantation may be enhanced by means of irradiation of the article with radiation of energy sufficient to enhance diffusion of the ions into the article. The dry lubricant ions may comprise Mo + , In + , or Sn + . Where the article is of steel suitable ions are Mo + and S + deposited in the ratio of 1:2. Examples of application of the method are given, using a 500 Kv Cockcroft-Walton accelerator for the implantation. (U.K.)

  9. Metal accumulation by stream bryophytes, related to chemical speciation

    Energy Technology Data Exchange (ETDEWEB)

    Tipping, E. [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom)], E-mail: et@ceh.ac.uk; Vincent, C.D.; Lawlor, A.J.; Lofts, S. [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom)

    2008-12-15

    Metal accumulation by aquatic bryophytes was investigated using data for headwater streams of differing chemistry. The Windermere Humic Aqueous Model (WHAM) was applied to calculate chemical speciation, including competitive proton and metal interactions with external binding sites on the plants. The speciation modelling approach gives smaller deviations between observed and predicted bryophyte contents of Cu, Zn, Cd and Pb than regressions based on total filtered metal concentrations. If all four metals, and Ni, are considered together, the WHAM predictions are superior at the 1% level. Optimised constants for bryophyte binding by the trace metals are similar to those for humic substances and simple carboxylate ligands. Bryophyte contents of Na, Mg and Ca are approximately explained by binding at external sites, while most of the K is intracellular. Oxide phases account for some of the Al, and most of the Mn, Fe and Co. - Speciation modelling can be used to interpret the accumulation of Ni, Cu, Zn, Cd and Pb by bryophytes, supporting its use to quantify trace metal bioavailability in the field.

  10. Investigations on the metabolism of metals in decapod crustaceas in relation with moulting cycles and reproduction

    International Nuclear Information System (INIS)

    Martin, J.-L.M.

    1975-07-01

    A study of the metabolism of metals was carried out in decapod crustaceas; it showed that it was subject to cyclic variations during the life of the animals, closely correlated with growth moults. The metabolism of metals was also considered in its relations with reproduction, especially oogenesis and spermatogenesis, and embryonic development. In relation with moult, various factors playing a role on metal metabolism were investigated: role of metals in the organism, fasting and nutrition cycles and biochemical reserves, physico-chemical form of the metal and ultrastructure of uptake surfaces. The histological and histochemical aspects of the uptake of a number of metals were studied as well as inter-metallic and inter-organic relationships [fr

  11. Heavy metals in surface sediments of the Jialu River, China: Their relations to environmental factors

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jie [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849 (United States); Zhao, Changpo [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Luo, Yupeng [Department of Mathematics and Statistics, Auburn University, Auburn, AL 36849 (United States); Liu, Chunsheng, E-mail: liuchunshengidid@126.com [College of Fisheries, Huazhong Agricultural University, Wuhan 430070 (China); Kyzas, George Z. [Laboratory of General and Inorganic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece); Luo, Yin [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Zhao, Dongye [Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849 (United States); An, Shuqing [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Zhu, Hailiang, E-mail: zhuhl@nju.edu.cn [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China)

    2014-04-01

    Highlights: • Zhengzhou City had major effect on the pollution of the Jialu River. • TN, OP, TP and COD{sub Mn} in water drove heavy metals to deposit in sediments. • B-IBI was sensitive to the adverse effect of heavy metals in sediments. - Abstract: This work investigated heavy metal pollution in surface sediments of the Jialu River, China. Sediment samples were collected at 19 sites along the river in connection with field surveys and the total concentrations were determined using atomic fluorescence spectrometer and inductively coupled plasma optical emission spectrometer. Sediment samples with higher metal concentrations were collected from the upper reach of the river, while sediments in the middle and lower reaches had relatively lower metal concentrations. Multivariate techniques including Pearson correlation, hierarchical cluster and principal components analysis were used to evaluate the metal sources. The ecological risk associated with the heavy metals in sediments was rated as moderate based on the assessments using methods of consensus-based Sediment Quality Guidelines, Potential Ecological Risk Index and Geo-accumulation Index. The relations between heavy metals and various environmental factors (i.e., chemical properties of sediments, water quality indices and aquatic organism indices) were also studied. Nitrate nitrogen, total nitrogen, and total polycyclic aromatic hydrocarbons concentrations in sediments showed a co-release behavior with heavy metals. Ammonia nitrogen, total nitrogen, orthophosphate, total phosphate and permanganate index in water were found to be related to metal sedimentation. Heavy metals in sediments posed a potential impact on the benthos community.

  12. Heavy metals in surface sediments of the Jialu River, China: Their relations to environmental factors

    International Nuclear Information System (INIS)

    Fu, Jie; Zhao, Changpo; Luo, Yupeng; Liu, Chunsheng; Kyzas, George Z.; Luo, Yin; Zhao, Dongye; An, Shuqing; Zhu, Hailiang

    2014-01-01

    Highlights: • Zhengzhou City had major effect on the pollution of the Jialu River. • TN, OP, TP and COD Mn in water drove heavy metals to deposit in sediments. • B-IBI was sensitive to the adverse effect of heavy metals in sediments. - Abstract: This work investigated heavy metal pollution in surface sediments of the Jialu River, China. Sediment samples were collected at 19 sites along the river in connection with field surveys and the total concentrations were determined using atomic fluorescence spectrometer and inductively coupled plasma optical emission spectrometer. Sediment samples with higher metal concentrations were collected from the upper reach of the river, while sediments in the middle and lower reaches had relatively lower metal concentrations. Multivariate techniques including Pearson correlation, hierarchical cluster and principal components analysis were used to evaluate the metal sources. The ecological risk associated with the heavy metals in sediments was rated as moderate based on the assessments using methods of consensus-based Sediment Quality Guidelines, Potential Ecological Risk Index and Geo-accumulation Index. The relations between heavy metals and various environmental factors (i.e., chemical properties of sediments, water quality indices and aquatic organism indices) were also studied. Nitrate nitrogen, total nitrogen, and total polycyclic aromatic hydrocarbons concentrations in sediments showed a co-release behavior with heavy metals. Ammonia nitrogen, total nitrogen, orthophosphate, total phosphate and permanganate index in water were found to be related to metal sedimentation. Heavy metals in sediments posed a potential impact on the benthos community

  13. Rational design of mesoporous metals and related nanomaterials by a soft-template approach.

    Science.gov (United States)

    Yamauchi, Yusuke; Kuroda, Kazuyuki

    2008-04-07

    We review recent developments in the preparation of mesoporous metals and related metal-based nanomaterials. Among the many types of mesoporous materials, mesoporous metals hold promise for a wide range of potential applications, such as in electronic devices, magnetic recording media, and metal catalysts, owing to their metallic frameworks. Mesoporous metals with highly ordered networks and narrow pore-size distributions have traditionally been produced by using mesoporous silica as a hard template. This method involves the formation of an original template followed by deposition of metals within the mesopores and subsequent removal of the template. Another synthetic method is the direct-template approach from lyotropic liquid crystals (LLCs) made of nonionic surfactants at high concentrations. Direct-template synthesis creates a novel avenue for the production of mesoporous metals as well as related metal-based nanomaterials. Many mesoporous metals have been prepared by the chemical or electrochemical reduction of metal salts dissolved in aqueous LLC domains. As a soft template, LLCs are more versatile and therefore more advantageous than hard templates. It is possible to produce various nanostructures (e.g., lamellar, 2D hexagonal (p6mm), and 3D cubic (Ia\\3d)), nanoparticles, and nanotubes simply by controlling the composition of the reaction bath.

  14. Volcano Relation for the Deacon Process over Transition-Metal Oxides

    DEFF Research Database (Denmark)

    Studt, Felix; Abild-Pedersen, Frank; Hansen, Heine Anton

    2010-01-01

    We establish an activity relation for the heterogeneous catalytic oxidation of HCI (the Deacon Process) over rutile transition-metal oxide catalysts by combining density functional theory calculations (DFT) with microkinetic modeling. Linear energy relations for the elementary reaction steps...

  15. The risk of cataract in relation to metal arc welding

    DEFF Research Database (Denmark)

    Slagor, Rebekka Michaelsen; Dornonville de la Cour, Morten; Bonde, Jens Peter

    2016-01-01

    .95–1.21] and the adjusted HR was 1.08 (95% CI 0.95–1.22). Age and diabetes were as expected strong risk factors. Conclusion: We found no increased risk of developing cataract among Danish metal welders who worked with arc welding from 1950–1985. This may be attributed to the effectiveness of personal safety equipment....... increases the risk of cataract. Method: We compared the risk of being diagnosed with cataract from 1987–2012 in a historic cohort of 4288 male metal arc welders against a reference group comprised of Danish skilled and unskilled male workers with similar age distribution. For the welders’ cohort...... adjusted for baseline data regarding age, diabetes, and social group. Results: There were 266 welders and 29 007 referents with a diagnosis and/or operation for cataract. The unadjusted HR for cataract comparing ever-welders with referents was 1.07 [95% confidence interval (95% CI) 0...

  16. Relations between age, metallicity and kinematics of F-G stars of the Galactic disk

    International Nuclear Information System (INIS)

    Shevelev, Yu.G.; Marsakov, V.A.; Suchkov, A.A.

    1989-01-01

    The data for ∼ 5500 F-G stars are used to study their kinematics, metal abindance and HR diagram in terms of uvby photometry. The age-metallicity, velocity-metallicity, and age-velocity relations are derived. An estimate for the age of the galactic disk is obtained. The following is shown: 1) At[Fe/H] -0.1, turn out to be kinematically younger than these G dwarfs. The same paradox is revealed by G and K giants

  17. Heavy metals in surface sediments of the Jialu River, China: their relations to environmental factors.

    Science.gov (United States)

    Fu, Jie; Zhao, Changpo; Luo, Yupeng; Liu, Chunsheng; Kyzas, George Z; Luo, Yin; Zhao, Dongye; An, Shuqing; Zhu, Hailiang

    2014-04-15

    This work investigated heavy metal pollution in surface sediments of the Jialu River, China. Sediment samples were collected at 19 sites along the river in connection with field surveys and the total concentrations were determined using atomic fluorescence spectrometer and inductively coupled plasma optical emission spectrometer. Sediment samples with higher metal concentrations were collected from the upper reach of the river, while sediments in the middle and lower reaches had relatively lower metal concentrations. Multivariate techniques including Pearson correlation, hierarchical cluster and principal components analysis were used to evaluate the metal sources. The ecological risk associated with the heavy metals in sediments was rated as moderate based on the assessments using methods of consensus-based Sediment Quality Guidelines, Potential Ecological Risk Index and Geo-accumulation Index. The relations between heavy metals and various environmental factors (i.e., chemical properties of sediments, water quality indices and aquatic organism indices) were also studied. Nitrate nitrogen, total nitrogen, and total polycyclic aromatic hydrocarbons concentrations in sediments showed a co-release behavior with heavy metals. Ammonia nitrogen, total nitrogen, orthophosphate, total phosphate and permanganate index in water were found to be related to metal sedimentation. Heavy metals in sediments posed a potential impact on the benthos community. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. NMR determination of chemically related metals in solution as a new method of inorganic analysis

    International Nuclear Information System (INIS)

    Fedorov, L.A.

    1989-01-01

    An NMR spectroscopic method for the determination of chemically related metals in solution is suggested. The metals are determined in complexes with specially selected polydentate ligands. Structural requirements to ligands, analytical properties and general limits of the application of the method are discussed. (orig.)

  19. The Universal Stellar Mass-Stellar Metallicity Relation for Dwarf Galaxies

    OpenAIRE

    Kirby, Evan N.; Cohen, Judith G.; Guhathakurta, Puragra; Cheng, Lucy; Bullock, James S.; Gallazzi, Anna

    2013-01-01

    We present spectroscopic metallicities of individual stars in seven gas-rich dwarf irregular galaxies (dIrrs), and we show that dIrrs obey the same massmetallicity relation as the dwarf spheroidal (dSph) satellites of both the Milky Way and M31: Z * σ M * 0.30±0. 02 . The uniformity of the relation is in contradiction to previous estimates of metallicity based on photometry. This relationship is roughly continuous with the stellar massstellar metallicity relation for galaxies as massive asM*...

  20. Nonlinear Color–Metallicity Relations of Globular Clusters. VII. Nonlinear Absorption-line Index versus Metallicity Relations and Bimodal Index Distributions of NGC 5128 Globular Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sooyoung; Yoon, Suk-Jin, E-mail: sjyoon0691@yonsei.ac.kr [Department of Astronomy and Center for Galaxy Evolution Research, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2017-07-01

    Spectroscopy on the globular cluster (GC) system of NGC 5128 revealed bimodality in absorption-line index distributions of its old GCs. GC division is a widely observed and studied phenomenon whose interpretation has depicted host galaxy formation and evolution such that it harbors two distinct metallicity groups. Such a conventional view of GC bimodality has mainly been based on photometry. The recent GC photometric data, however, presented an alternative perspective in which the nonlinear metallicity-to-color transformation is responsible for color bimodality of GC systems. Here we apply the same line of analysis to the spectral indices and examine the absorption-line index versus metallicity relations for the NGC 5128 GC system. NGC 5128 GCs display nonlinearity in the metallicity-index planes, most prominently for the Balmer lines and by a non-negligible degree for the metallicity-sensitive magnesium line. We demonstrate that the observed spectroscopic division of NGC 5128 GCs can be caused by the nonlinear nature of the metallicity-to-index conversions and thus one does not need to resort to two separate GC subgroups. Our analysis incorporating this nonlinearity provides a new perspective on the structure of NGC 5128's GC system, and a further piece to the global picture of the formation of GC systems and their host galaxies.

  1. On the Origin of the Mass-Metallicity Relation for GRB Host Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Kocevski, Daniel; /KIPAC, Menlo Park; West, Andrew A.; /Boston U., Dept. Astron.

    2011-06-02

    We investigate the nature of the mass-metallicity (M-Z) relation for long gamma-ray burst (LGRB) host galaxies. Recent studies suggest that the M-Z relation for local LGRB host galaxies may be systematically offset towards lower metallicities relative to the M-Z relation defined by the general star forming galaxy (SDSS) population. The nature of this offset is consistent with suggestions that low metallicity environments may be required to produce high mass progenitors, although the detection of several GRBs in high-mass, high-metallicity galaxies challenges the notion of a strict metallicity cut-off for host galaxies that are capable of producing GRBs. We show that the nature of this reported offset may be explained by a recently proposed anti-correlation between the star formation rate (SFR) and the metallicity of star forming galaxies. If low metallicity galaxies produce more stars than their equally massive, high-metallicity counterparts, then transient events that closely trace the SFR in a galaxy would be more likely to be found in these low metallicity, low mass galaxies. Therefore, the offset between the GRB and SDSS defined M-Z relations may be the result of the different methods used to select their respective galaxy populations, with GRBs being biased towards low metallicity, high SFR, galaxies. We predict that such an offset should not be expected of transient events that do not closely follow the star formation history of their host galaxies, such as short duration GRBs and SN Ia, but should be evident in core collapse SNe found through upcoming untargeted surveys.

  2. Dispersion relations of the acoustic modes in divalent liquid metals

    Directory of Open Access Journals (Sweden)

    Inui Masanori

    2017-01-01

    Full Text Available Collective dynamics in liquid Ca and liquid Cd was studied by inelastic x-ray scattering (IXS. Using our experimental technique to prepare proper sample cells and high performance of an IXS beamline (BL35XU at SPring-8 in Japan, the dynamic structure factor with reasonable statistics was obtained for these divalent liquid metals. For both liquids, the dynamic structure factor at low Q exhibits a central peak with a shoulder or small hump clearly visible on each side, and the inelastic excitation energy determined using the model function composed of Lorentzian and the damped harmonic oscillator function disperses with increasing Q. The dispersion curves of these liquids were compared with that of the longitudinal acoustic phonon in each crystalline phase. From these results, clear difference in the interatomic interaction be- tween liquid Ca and liquid Cd was inferred.

  3. [Investigation and analysis of heavy metal pollution related to soil-Panax notoginseng system].

    Science.gov (United States)

    Chen, Lu; Mi, Yan-Hua; Lin, Xin; Liu, Da-Hui; Zeng, Min; Chen, Xiao-Yan

    2014-07-01

    In this study, five heavy metals contamination of soil and different parts of Panax notoginseng in the plantation area was investigated. Analysis of heavy metals correlation between the planting soil and P. notoginseng; and the absorption and accumulation characteristics and translocation of soil heavy metals by P. notoginseng plants was revealed. Through field investigation and laboratory analytical methods, analysis of China's 30 different soil P. notoginseng origin and content of heavy metals in five different parts of the P. notoginseng plant content of heavy metals. The results revealed that the soil heavy metals should not be neglected in the plantation area Referring to the national soil quality standards (GB15608-1995), the excessive degree of soil heavy metals pollution showed Hg > As > Cd > Cr in the plantation area, and Pb content of soil was in the scope of the standard. Refer to 'Green Industry Standards for Import and Export of Medical Plants and Preparations', the excessive degree of heavy metals content of P. notoginseng plants showed As > Pb > Cr > Cd, and Hg content of plants was in the scope of the standard. Concentrations of five heavy metals of underground parts of P. notoginseng plants are higher than aboveground, and heavy metals elements are more concentrated in the root, followed by the rhizome of P. notoginseng plants. Heavy metal accumulation characteristics of the different parts of the P. notoginseng of the overall performance is the root > the rhizome > the root tuber > leaves > stems. From the point of view BCF value analysis of various parts of the P. notoginseng plants to absorb heavy metals in soil, BCF values of all samples were less than 1, description P. notoginseng not belong Hyperaccumulator. From the view of transportation and related analysis of the soil-P. notoginseng systems, the rhizome of P. notoginseng and the content of As and Cr in soil was significantly correlated, the root of P. notoginseng and the content of Cd in

  4. Hotspot related plasmon assisted multiphoton photocurrents in metal-insulator-metal junctions

    Energy Technology Data Exchange (ETDEWEB)

    Differt, Dominik; Pfeiffer, Walter [Universitaet Bielefeld, Universitaetsstr. 25, 33615 Bielefeld (Germany); Diesing, Detlef [Universitaet Duisburg-Essen, Universitaetsstr. 5, 45117 Essen (Germany)

    2011-07-01

    Scanning photocurrent microscopy of metal-insulator-metal junctions (MIM) is used to investigate the mechanisms of femtosecond multiphoton photocurrent injection at liquid nitrogen temperature. The locally induced multiphoton photocurrent in a Ag-TaO-Ta MIM junction is measured in a scanning microscope cryostat under focused illumination (5{mu}m focus diameter, 800 nm, 30 fs, 80 MHz repetition rate). The intensity dependence reveals a mixture of two-photon and three-photon processes that are responsible for the photocurrent. Its lateral variation shows hotspot-like behaviour with significant magnitude variations on a 100 to 200 nm length scale. Assuming an injection current duration of 40fs the peak injection current density of about 10{sup 4} A cm{sup -2} is estimated - 10{sup 6} times higher than that for 400 nm continuous wave illumination slightly below the damage threshold. The simultaneously measured extinction of the incident radiation reveals a 20 to 30% increased absorption at the hotspots. We attribute the local photocurrent enhancement to the defect-assisted excitation of surface plasmon polaritons at the silver electrode leading to an enhanced local excitation.

  5. THE MASS-METALLICITY RELATION WITH THE DIRECT METHOD ON STACKED SPECTRA OF SDSS GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, Brett H.; Martini, Paul, E-mail: andrews@astronomy.ohio-state.edu [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)

    2013-03-10

    The relation between galaxy stellar mass and gas-phase metallicity is a sensitive diagnostic of the main processes that drive galaxy evolution, namely cosmological gas inflow, metal production in stars, and gas outflow via galactic winds. We employed the direct method to measure the metallicities of {approx}200,000 star-forming galaxies from the Sloan Digital Sky Survey that were stacked in bins of (1) stellar mass and (2) both stellar mass and star formation rate (SFR) to significantly enhance the signal-to-noise ratio of the weak [O III] {lambda}4363 and [O II] {lambda}{lambda}7320, 7330 auroral lines required to apply the direct method. These metallicity measurements span three decades in stellar mass from log(M{sub *}/M{sub Sun }) = 7.4-10.5, which allows the direct method mass-metallicity relation to simultaneously capture the high-mass turnover and extend a full decade lower in mass than previous studies that employed more uncertain strong line methods. The direct method mass-metallicity relation rises steeply at low mass (O/H {proportional_to} M{sub *} {sup 1/2}) until it turns over at log(M{sub *}/M{sub Sun }) = 8.9 and asymptotes to 12 + log(O/H) = 8.8 at high mass. The direct method mass-metallicity relation has a steeper slope, a lower turnover mass, and a factor of two to three greater dependence on SFR than strong line mass-metallicity relations. Furthermore, the SFR-dependence appears monotonic with stellar mass, unlike strong line mass-metallicity relations. We also measure the N/O abundance ratio, an important tracer of star formation history, and find the clear signature of primary and secondary nitrogen enrichment. N/O correlates tightly with oxygen abundance, and even more so with stellar mass.

  6. Relation between tobacco trace metals and soil type in Lebanon

    International Nuclear Information System (INIS)

    SLIM, K.; Saad, Z.; Kazpard, V.; El Samarani, A; Nabhan, Ph.

    2006-01-01

    The aim of study was to determine the concentration of nutrients in soil and tobacco samples from different agricultural regions. We studied the influence of soil type on tobacco quality and the transfer and accumulation of trace metals in tobacco leaves. The results showed that human activities in the Nabatiyeh region had a none pronounced effect on one agricultural plot than on its neighbor. The transfer factor of elements between soil and tobacco plants showed that major constituents are leached and absorbed from the soil, whereas some trace elements are finely absorbed from the alkaline soil. Statistical analysis of the micro nutrients in soil and plants confirmed the existence of two principal factors that control the distribution of elements in different compartments. Four tobacco plots in different regions were also studied as a functions of their pedologic and geologic characteristics. The major elements varied in all regions, but were always ordered Ca > Mg > Na > K. The highest transfer factor for nutrients was found in young soil layers. In the Akkar region, clay nutrients form complexes with micronutrients. Thereby reducing their absorption by tobacco plants. (author)

  7. IMF–METALLICITY: A TIGHT LOCAL RELATION REVEALED BY THE CALIFA SURVEY

    International Nuclear Information System (INIS)

    Martín-Navarro, Ignacio; Vazdekis, Alexandre; Falcón-Barroso, Jesús; La Barbera, Francesco; Lyubenova, Mariya; Trager, S. C.; Ven, Glenn van de; Ferreras, Ignacio; Sánchez, S. F.; García-Benito, R.; Mendoza, M. A.; Mast, D.; Sánchez-Blázquez, P.

    2015-01-01

    Variations in the stellar initial mass function (IMF) have been invoked to explain the spectroscopic and dynamical properties of early-type galaxies (ETGs). However, no observations have yet been able to disentangle the physical driver. We analyze here a sample of 24 ETGs drawn from the CALIFA survey, deriving in a homogeneous way their stellar population and kinematic properties. We find that the local IMF is tightly related to the local metallicity, becoming more bottom-heavy toward metal-rich populations. Our result, combined with the galaxy mass–metallicity relation, naturally explains previous claims of a galaxy mass–IMF relation, derived from non-IFU spectra. If we assume that—within the star formation environment of ETGs—metallicity is the main driver of IMF variations, a significant revision of the interpretation of galaxy evolution observables is necessary

  8. The Impact Of Integrated Parameters In The Manga Local Mass-Metallicity Relation

    Science.gov (United States)

    Barrera-Ballesteros, Jorge K.

    2016-09-01

    We present the surface mass density - gas metallicity (Σ_*-Z) relation for more than 500,000 spatially-resolved star-forming regions from a sample of 617 disk galaxies included in the MaNGA survey. We find a tight relation between these local properties with higher metallicities as the surface density increases, resembling a scaled-down version of the relation found previously for their integrated counterparts. This relation expands over three orders of magnitude in the surface mass and a factor of 8 in metallicity. Our large sample allows us to study the impact of global properties in this local relation. In particular, we find that for most disk galaxies the Σ_*-Z relation does not depend on the total stellar mass. Even more, for a large fraction of our sample (log(M_*/M_{⊙}) > 9.2) the observed metallicity gradients are well reproduced by the mass density gradients and the Σ_*-Z relation. We also find that this relation does not change significantly within the range of redshifts span by our sample. Our results suggest as the predominant scenario for metal enrichment as gas been recycled locally at shorter timescales in comparison to other global processes such as gas accretion or outflows.

  9. Investigation of metal/carbon-related materials for fuel cell applications by electronic structure calculations

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Ki-jeong [Korea Research Institute of Chemical Technology, P.O.Box 107, Yuseong, Daejeon 305-600 (Korea, Republic of)]. E-mail: kong@krict.re.kr; Choi, Youngmin [Korea Research Institute of Chemical Technology, P.O.Box 107, Yuseong, Daejeon 305-600 (Korea, Republic of); Ryu, Beyong-Hwan [Korea Research Institute of Chemical Technology, P.O.Box 107, Yuseong, Daejeon 305-600 (Korea, Republic of); Lee, Jeong-O [Korea Research Institute of Chemical Technology, P.O.Box 107, Yuseong, Daejeon 305-600 (Korea, Republic of); Chang, Hyunju [Korea Research Institute of Chemical Technology, P.O.Box 107, Yuseong, Daejeon 305-600 (Korea, Republic of)

    2006-07-15

    The potential of carbon-related materials, such as carbon nanotubes (CNTs) and graphite nanofibers (GNFs), supported metal catalysts as an electrode for fuel cell application was investigated using the first-principle electronic structure calculations. The stable binding geometries and energies of metal catalysts are determined on the CNT surface and the GNF edge. The catalyst metal is more tightly bound to the GNF edge than to the CNT surface because of the existence of active dangling bonds of edge carbon atoms. The diffusion barrier of metal atoms on the surface and edge is also obtained. From our calculation results, we have found that high dispersity is achievable for GNF due to high barrier against the diffusion of metal atoms, while CNT appears less suitable. The GNF with a large edge-to-wall ratio is more suitable for the high-performance electrode than perfect crystalline graphite or CNT.

  10. Investigation of metal/carbon-related materials for fuel cell applications by electronic structure calculations

    International Nuclear Information System (INIS)

    Kong, Ki-jeong; Choi, Youngmin; Ryu, Beyong-Hwan; Lee, Jeong-O; Chang, Hyunju

    2006-01-01

    The potential of carbon-related materials, such as carbon nanotubes (CNTs) and graphite nanofibers (GNFs), supported metal catalysts as an electrode for fuel cell application was investigated using the first-principle electronic structure calculations. The stable binding geometries and energies of metal catalysts are determined on the CNT surface and the GNF edge. The catalyst metal is more tightly bound to the GNF edge than to the CNT surface because of the existence of active dangling bonds of edge carbon atoms. The diffusion barrier of metal atoms on the surface and edge is also obtained. From our calculation results, we have found that high dispersity is achievable for GNF due to high barrier against the diffusion of metal atoms, while CNT appears less suitable. The GNF with a large edge-to-wall ratio is more suitable for the high-performance electrode than perfect crystalline graphite or CNT

  11. A METALLICITY-SPIN TEMPERATURE RELATION IN DAMPED Lyα SYSTEMS

    International Nuclear Information System (INIS)

    Kanekar, Nissim; Smette, Alain; Briggs, Frank H.; Chengalur, Jayaram N.

    2009-01-01

    We report evidence for an anti-correlation between spin temperature T s and metallicity [Z/H], detected at 3.6σ significance in a sample of 26 damped Lyα absorbers (DLAs) at redshifts 0.09 s = (-0.68 ± 0.17) x [Z/H] + (2.13 ± 0.21) from a linear regression analysis. Our results indicate that the high T s values found in DLAs do not arise from differences between the optical and radio sightlines, but are likely to reflect the underlying gas temperature distribution. The trend between T s and [Z/H] can be explained by the larger number of radiation pathways for gas cooling in galaxies with high metal abundances, resulting in a high cold gas fraction, and hence, a low spin temperature. Conversely, low-metallicity galaxies have fewer cooling routes, yielding a larger warm gas fraction and a high T s . Most DLAs at z > 1.7 have low metallicities, [Z/H] s and [Z/H] is consistent with the presence of a mass-metallicity relation in DLAs, suggested by the tight correlation between DLA metallicity and the kinematic widths of metal lines. Most high-z DLAs are likely to arise in galaxies with low masses (M vir 10.5 M sun ), low metallicities ([Z/H] <-1), and low cold gas fractions.

  12. Using scaling relations to understand trends in the catalytic activity of transition metals

    International Nuclear Information System (INIS)

    Jones, G; Bligaard, T; Abild-Pedersen, F; Noerskov, J K

    2008-01-01

    A method is developed to estimate the potential energy diagram for a full catalytic reaction for a range of late transition metals on the basis of a calculation (or an experimental determination) for a single metal. The method, which employs scaling relations between adsorption energies, is illustrated by calculating the potential energy diagram for the methanation reaction and ammonia synthesis for 11 different metals on the basis of results calculated for Ru. It is also shown that considering the free energy diagram for the reactions, under typical industrial conditions, provides additional insight into reactivity trends

  13. THE METALLICITY BIMODALITY OF GLOBULAR CLUSTER SYSTEMS: A TEST OF GALAXY ASSEMBLY AND OF THE EVOLUTION OF THE GALAXY MASS-METALLICITY RELATION

    International Nuclear Information System (INIS)

    Tonini, Chiara

    2013-01-01

    We build a theoretical model to study the origin of the globular cluster metallicity bimodality in the hierarchical galaxy assembly scenario. The model is based on empirical relations such as the galaxy mass-metallicity relation [O/H]-M star as a function of redshift, and on the observed galaxy stellar mass function up to redshift z ∼ 4. We make use of the theoretical merger rates as a function of mass and redshift from the Millennium simulation to build galaxy merger trees. We derive a new galaxy [Fe/H]-M star relation as a function of redshift, and by assuming that globular clusters share the metallicity of their original parent galaxy at the time of their formation, we populate the merger tree with globular clusters. We perform a series of Monte Carlo simulations of the galaxy hierarchical assembly, and study the properties of the final globular cluster population as a function of galaxy mass, assembly and star formation history, and under different assumptions for the evolution of the galaxy mass-metallicity relation. The main results and predictions of the model are the following. (1) The hierarchical clustering scenario naturally predicts a metallicity bimodality in the galaxy globular cluster population, where the metal-rich subpopulation is composed of globular clusters formed in the galaxy main progenitor around redshift z ∼ 2, and the metal-poor subpopulation is composed of clusters accreted from satellites, and formed at redshifts z ∼ 3-4. (2) The model reproduces the observed relations by Peng et al. for the metallicities of the metal-rich and metal-poor globular cluster subpopulations as a function of galaxy mass; the positions of the metal-poor and metal-rich peaks depend exclusively on the evolution of the galaxy mass-metallicity relation and the [O/Fe], both of which can be constrained by this method. In particular, we find that the galaxy [O/Fe] evolves linearly with redshift from a value of ∼0.5 at redshift z ∼ 4 to a value of ∼0.1 at

  14. The Origin of the Relation between Metallicity and Size in Star-forming Galaxies

    Science.gov (United States)

    Sánchez Almeida, J.; Dalla Vecchia, C.

    2018-06-01

    For the same stellar mass, physically smaller star-forming galaxies are also metal richer. What causes the relation remains unclear. The central star-forming galaxies in the EAGLE cosmological numerical simulation reproduce the observed trend. We use them to explore the origin of the relation assuming that the physical mechanism responsible for the anticorrelation between size and gas-phase metallicity is the same in the simulated and the observed galaxies. We consider the three most likely causes: (1) metal-poor gas inflows feeding the star formation (SF) process, (2) metal-rich gas outflows particularly efficient in shallow gravitational potentials, and (3) enhanced efficiency of the SF process in compact galaxies. Outflows (cause 2) and enhanced SF efficiency (cause 3) can be discarded. Metal-poor gas inflows (cause 1) produce the correlation in the simulated galaxies. Galaxies grow in size with time, so those that receive gas later are both metal poorer and larger, giving rise to the observed anticorrelation. As expected within this explanation, larger galaxies have younger stellar populations. We explore the variation with redshift of the relation, which is maintained up to, at least, redshift 8.

  15. On the behavior of Brønsted-Evans-Polanyi relations for transition metal oxides

    DEFF Research Database (Denmark)

    Vojvodic, Aleksandra; Vallejo, Federico Calle; Guo, Wei

    2011-01-01

    Versatile Brønsted-Evans-Polanyi (BEP) relations are found from density functional theory for a wide range of transition metal oxides including rutiles and perovskites. For oxides, the relation depends on the type of oxide, the active site, and the dissociating molecule. The slope of the BEP...

  16. Heavy metal content of lichens in relation to distance from a nickel smelter in Sudbury, Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Nieboer, E; Ahmed, H M; Puckett, K J; Richardson, D H.S.

    1972-01-01

    The Sudbury region of Ontario has large deposits of nickel, iron, and copper, and thus a number of smelting plants which produce sulfur dioxide and heavy metal pollution. Since lichens are good indicators of SO/sub 2/ pollution levels, the pattern of heavy metal content in lichen species in the area of a copper smelter in Sudbury was correlated with distance from the smelter to ascertain whether lichens might also be good indicators of the amount of heavy metal fallout. The lichens were analyzed qualitatively and quantitatively. All seven species of lichens contained copper, iron, zinc, nickel, manganese, and lead. Cadmium and cobalt were detected in two species. Neither gold nor silver could be identified in lichen material with the tests used. A pollution model was developed and compared to field results. The simple dilution of the stack effluent was consistent with the fact that the lichen metal content was related to the reciprocal of the distance from the pollution source. The lichens from the area could tolerate simultaneously high concentrations of several heavy metals that are known to be toxic to other plants. The mechanism of metal uptake was not clearly established. The study showed that lichens and other epiphytes are potentially the most useful indicators of heavy metal fallout around industrial plants.

  17. Long-term field metal extraction by Pelargonium: phytoextraction efficiency in relation to plant maturity.

    Science.gov (United States)

    Shahid, Muhammad; Arshad, Muhammad; Kaemmerer, Michel; Pinelli, Eric; Probst, Anne; Baque, David; Pradere, Philippe; Dumat, Camille

    2012-01-01

    The long length of periods required for effective soil remediation via phytoextraction constitutes a weak point that reduces its industrial use. However, these calculated periods are mainly based on short-term and/or hydroponic controlled experiments. Moreover, only a few studies concern more than one metal, although soils are scarcely polluted by only one element. In this scientific context, the phytoextraction of metals and metalloids (Pb, Cd, Zn, Cu, and As) by Pelargonium was measured after a long-term field experiment. Both bulk and rhizosphere soils were analyzed in order to determine the mechanisms involved in soil-root transfer. First, a strong increase in lead phytoextraction was observed with plant maturity, significantly reducing the length of the period required for remediation. Rhizosphere Pb, Zn, Cu, Cd, and As accumulation was observed (compared to bulk soil), indicating metal mobilization by the plant, perhaps in relation to root activity. Moreover, metal phytoextraction and translocation were found to be a function of the metals' nature. These results, taken altogether, suggest that Pelargonium could be used as a multi-metal hyperaccumulator under multi-metal soil contamination conditions, and they also provide an interesting insight for improving field phytoextraction remediation in terms of the length of time required, promoting this biological technique.

  18. Relating metal bioavailability to risk assessment for aquatic species: Daliao River watershed, China

    International Nuclear Information System (INIS)

    Han, Shuping; Zhang, Ying; Masunaga, Shigeki; Zhou, Siyun; Naito, Wataru

    2014-01-01

    The spatial distribution of metal bioavailability (Ni, Cu, Zn, and Pb) was first evaluated within the waters of Daliao River watershed, using the diffusive gradient in thin films (DGT) and chemical equilibrium models. To assess potential risks associated with metal bioavailability, site-specific 95% protection levels (HC5), risk characterizations ratios (RCR) and ratios of DGT-labile/HC5 were derived, using species sensitivity distribution (SSD). The highest bioavailability values for metals were recorded in the main channel of the Daliao River, followed by the Taizi River. Dynamic concentrations predicted by WHAM 7.0 and NICA-Donnan for Cu and Zn agreed well with DGT results. The estuary of the Daliao River was found to have the highest risks related to Ni, Cu, and Zn. The number of sites at risk increased when considering the total toxicity of Ni, Cu, and Zn. - Highlights: • Spatial variation in metal bioavailability within Daliao River watershed was studied. • WHAM 7.0 and NICA-Donnan examined the differences in predicting metal speciation. • Bioavailability values of metals were highest in main channel of the Daliao River. • Site-specific 95% protection levels (HC5)/risk variations were assessed using SSD. • Maximum risks from Ni, Cu, and Zn occurred in the estuary of the Daliao River. - The highest bioavailability values and the highest risks of metals were found in the estuary of the Daliao River

  19. The role of atomic hydrogen in regulating the scatter of the mass-metallicity relation

    Science.gov (United States)

    Brown, Toby; Cortese, Luca; Catinella, Barbara; Kilborn, Virginia

    2018-01-01

    In this paper, we stack neutral atomic hydrogen (H I) spectra for 9720 star-forming galaxies along the mass-metallicity relation. The sample is selected according to stellar mass (109 ≤ M⋆/M⊙ ≤ 1011) and redshift (0.02 ≤ z ≤ 0.05) from the overlap of the Sloan Digital Sky Survey and Arecibo Legacy Fast ALFA survey. We confirm and quantify the strong anticorrelation between H I mass and gas-phase metallicity at fixed stellar mass. Furthermore, we show for the first time that the relationship between gas content and metallicity is consistent between different metallicity estimators, contrary to the weaker trends found with star formation which are known to depend on the observational techniques used to derive oxygen abundances and star formation rates. When interpreted in the context of theoretical work, this result supports a scenario where galaxies exist in an evolving equilibrium between gas, metallicity and star formation. The fact that deviations from this equilibrium are most strongly correlated with gas mass suggests that the scatter in the mass-metallicity relation is primarily driven by fluctuations in gas accretion.

  20. Metal status in human endometrium: Relation to cigarette smoking and histological lesions

    International Nuclear Information System (INIS)

    Rzymski, Piotr; Rzymski, Paweł; Tomczyk, Katarzyna; Niedzielski, Przemysław; Jakubowski, Karol; Poniedziałek, Barbara; Opala, Tomasz

    2014-01-01

    Human endometrium is a thick, blood vessel-rich, glandular tissue which undergoes cyclic changes and is potentially sensitive to the various endogenous and exogenous compounds supplied via the hematogenous route. As recently indicated, several metals including Cd, Pb, Cr and Ni represent an emerging class of potential metalloestrogens and can be implicated in alterations of the female reproductive system including endometriosis and cancer. In the present study, we investigated the content of five metals: Cd, Cr, Ni, Pb and Zn in 25 samples of human endometrium collected from Polish females undergoing diagnostic or therapeutic curettage of the uterine cavity. The overall mean metal concentration (analyzed using microwave induced plasma atomic emission spectrometry MIP-OES) decreased in the following order: Cr>Pb>Zn>Ni>Cd. For the first time it was demonstrated that cigarette smoking significantly increases the endometrial content of Cd and Pb. Concentration of these metals was also positively correlated with years of smoking and the number of smoked cigarettes. Tissue samples with recognized histologic lesions (simple hyperplasia, polyposis and atrophy) were characterized by a 2-fold higher Cd level. No relation between the age of the women and metal content was found. Our study shows that human endometrium can be a potential target of metal accumulation within the human body. Quantitative analyses of endometrial metal content could serve as an additional indicator of potential impairments of the menstrual cycle and fertility. - Highlights: • Cd, Cr, Ni, Pb and Zn are detectable in human endometrium. • Mean metal content in human endometrium decreases in Cr>Pb>Zn>Ni>Cd order. • Cigarettes smoking increases endometrial content of Cd and Pb. • Lesioned endometrial tissue was characterized by higher metal contents

  1. Metal status in human endometrium: Relation to cigarette smoking and histological lesions

    Energy Technology Data Exchange (ETDEWEB)

    Rzymski, Piotr, E-mail: rzymskipiotr@ump.edu.pl [Department of Biology and Environmental Protection, Poznan University of Medical Sciences, Rokietnicka 8, 60-806 Poznań (Poland); Rzymski, Paweł; Tomczyk, Katarzyna [Department of Mother' s and Child' s Health, Gynecologic and Obstetrical University Hospital, Poznan University of Medical Sciences, Poznań (Poland); Niedzielski, Przemysław; Jakubowski, Karol [Department of Analytical Chemistry, Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań (Poland); Poniedziałek, Barbara [Department of Biology and Environmental Protection, Poznan University of Medical Sciences, Rokietnicka 8, 60-806 Poznań (Poland); Opala, Tomasz [Department of Mother' s and Child' s Health, Gynecologic and Obstetrical University Hospital, Poznan University of Medical Sciences, Poznań (Poland)

    2014-07-15

    Human endometrium is a thick, blood vessel-rich, glandular tissue which undergoes cyclic changes and is potentially sensitive to the various endogenous and exogenous compounds supplied via the hematogenous route. As recently indicated, several metals including Cd, Pb, Cr and Ni represent an emerging class of potential metalloestrogens and can be implicated in alterations of the female reproductive system including endometriosis and cancer. In the present study, we investigated the content of five metals: Cd, Cr, Ni, Pb and Zn in 25 samples of human endometrium collected from Polish females undergoing diagnostic or therapeutic curettage of the uterine cavity. The overall mean metal concentration (analyzed using microwave induced plasma atomic emission spectrometry MIP-OES) decreased in the following order: Cr>Pb>Zn>Ni>Cd. For the first time it was demonstrated that cigarette smoking significantly increases the endometrial content of Cd and Pb. Concentration of these metals was also positively correlated with years of smoking and the number of smoked cigarettes. Tissue samples with recognized histologic lesions (simple hyperplasia, polyposis and atrophy) were characterized by a 2-fold higher Cd level. No relation between the age of the women and metal content was found. Our study shows that human endometrium can be a potential target of metal accumulation within the human body. Quantitative analyses of endometrial metal content could serve as an additional indicator of potential impairments of the menstrual cycle and fertility. - Highlights: • Cd, Cr, Ni, Pb and Zn are detectable in human endometrium. • Mean metal content in human endometrium decreases in Cr>Pb>Zn>Ni>Cd order. • Cigarettes smoking increases endometrial content of Cd and Pb. • Lesioned endometrial tissue was characterized by higher metal contents.

  2. EXPLORING SYSTEMATIC EFFECTS IN THE RELATION BETWEEN STELLAR MASS, GAS PHASE METALLICITY, AND STAR FORMATION RATE

    International Nuclear Information System (INIS)

    Telford, O. Grace; Dalcanton, Julianne J.; Skillman, Evan D.; Conroy, Charlie

    2016-01-01

    There is evidence that the well-established mass–metallicity relation in galaxies is correlated with a third parameter: star formation rate (SFR). The strength of this correlation may be used to disentangle the relative importance of different physical processes (e.g., infall of pristine gas, metal-enriched outflows) in governing chemical evolution. However, all three parameters are susceptible to biases that might affect the observed strength of the relation between them. We analyze possible sources of systematic error, including sample bias, application of signal-to-noise ratio cuts on emission lines, choice of metallicity calibration, uncertainty in stellar mass determination, aperture effects, and dust. We present the first analysis of the relation between stellar mass, gas phase metallicity, and SFR using strong line abundance diagnostics from Dopita et al. for ∼130,000 star-forming galaxies in the Sloan Digital Sky Survey and provide a detailed comparison of these diagnostics in an appendix. Using these new abundance diagnostics yields a 30%–55% weaker anti-correlation between metallicity and SFR at fixed stellar mass than that reported by Mannucci et al. We find that, for all abundance diagnostics, the anti-correlation with SFR is stronger for the relatively few galaxies whose current SFRs are elevated above their past average SFRs. This is also true for the new abundance diagnostic of Dopita et al., which gives anti-correlation between Z and SFR only in the high specific star formation rate (sSFR) regime, in contrast to the recent results of Kashino et al. The poorly constrained strength of the relation between stellar mass, metallicity, and SFR must be carefully accounted for in theoretical studies of chemical evolution.

  3. Time-dependent inelastic analysis of metallic media using constitutive relations with state variables

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, V; Mukherjee, S [Cornell Univ., Ithaca, N.Y. (USA)

    1977-03-01

    A computational technique in terms of stress, strain and displacement rates is presented for the solution of boundary value problems for metallic structural elements at uniform elevated temperatures subjected to time varying loads. This method can accommodate any number of constitutive relations with state variables recently proposed by other researchers to model the inelastic deformation of metallic media at elevated temperatures. Numerical solutions are obtained for several structural elements subjected to steady loads. The constitutive relations used for these numerical solutions are due to Hart. The solutions are discussed in the context of the computational scheme and Hart's theory.

  4. Relation of radiation damage of metallic solids to electronic structure. Pt. 5

    International Nuclear Information System (INIS)

    Shalaev, A.M.; Adamenko, A.A.

    1977-01-01

    The problem of relating a damage in metal solids to the parameters of radiation fluxes and the physical nature of a target is considered. Basing upon experimental and theoretical investigations into the processes of interaction of particle fluxes with solids, the following conclusions have been reached. Threshold energy of ion displacement in the crystal lattice of a metal solid is dependent on the energy of a bombarding particle, which is due to ionization and electroexcitation stimulated by energy transfer from a fast particle to a system of collectivized electrons. The rate of metal solid damage by radiation depends on the state of the crystal lattice, in particular on its defectness. Variations of local electron density in the vicinity of a defect are related with changing thermodynamic characteristics of radiation-induced defect formation. A type of atomic bond in a solid affects the rate of radiation damage. The greatest damage occurs in materials with a covalent bond

  5. Multivariate analysis of selected metals in tannery effluents and related soil.

    Science.gov (United States)

    Tariq, Saadia R; Shah, Munir H; Shaheen, N; Khalique, A; Manzoor, S; Jaffar, M

    2005-06-30

    Effluent and relevant soil samples from 38 tanning units housed in Kasur, Pakistan, were obtained for metal analysis by flame atomic absorption spectrophotometric method. The levels of 12 metals, Na, Ca, K, Mg, Fe, Mn, Cr, Co, Cd, Ni, Pb and Zn were determined in the two media. The data were evaluated towards metal distribution and metal-to-metal correlations. The study evidenced enhanced levels of Cr (391, 16.7 mg/L) and Na (25,519, 9369 mg/L) in tannery effluents and relevant soil samples, respectively. The effluent versus soil trace metal content relationship confirmed that the effluent Cr was strongly correlated with soil Cr. For metal source identification the techniques of principal component analysis, and cluster analysis were applied. The principal component analysis yielded two factors for effluents: factor 1 (49.6% variance) showed significant loading for Ca, Fe, Mn, Cr, Cd, Ni, Pb and Zn, referring to a tanning related source for these metals, and factor 2 (12.6% variance) with higher loadings of Na, K, Mg and Co, was associated with the processes during the skin/hide treatment. Similarly, two factors with a cumulative variance of 34.8% were obtained for soil samples: factor 1 manifested the contribution from Mg, Mn, Co, Cd, Ni and Pb, which though soil-based is basically effluent-derived, while factor 2 was found associated with Na, K, Ca, Cr and Zn which referred to a tannery-based source. The dendograms obtained from cluster analysis, also support the observed results. The study exhibits a gross pollution of soils with Cr at levels far exceeding the stipulated safe limit laid down for tannery effluents.

  6. Accumulation of Heavy Metals in Roadside Soil in Urban Area and the Related Impacting Factors.

    Science.gov (United States)

    Wang, Meie; Zhang, Haizhen

    2018-05-24

    Heavy metal contamination in roadside soil due to traffic emission has been recognized for a long time. However, seldom has been reported regarding identification of critical factors influencing the accumulation of heavy metals in urban roadside soils due to the frequent disturbances such as the repair of damaged roads and green belt maintanance. Heavy metals in the roadside soils of 45 roads in Xihu district, Hangzhou city were investigated. Results suggested the accumulation of Cu, Pb, Cd, Cr, and Zn in roadside soil was affected by human activity. However, only two sites had Pb and Zn excessing the standards for residential areas, respectively, according to Chinese Environmental Quality Standards for soils. The concentrations of Cu, Pb, Cd, and Zn were significantly and positively correlated to soil pH and organic matter. An insignificant correlation between the age of the roads or vegetation cover types and the concentration of heavy metals was found although they were reported closely relating to the accumulation of heavy metals in roadside soils of highways. The highest Pb, Cd, and Cr taking place in sites with heavy traffic and significant differences in the concentrations of Cu, Pb, Cd, and Zn among the different categories of roads suggested the contribution of traffic intensity. However, it was difficult to establish a quantitative relationship between traffic intensity and the concentrations of heavy metals in the roadside soil. It could be concluded that impaction of traffic emission on the accumulation of heavy metals in roadside soils in urban area was slight and soil properties such as pH and organic matters were critical factors influencing the retention of heavy metals in soils.

  7. WE-AB-204-12: Dosimetry at the Sub-Cellular Scale of Auger-Electron Emitter 99m-Tc in a Mouse Single Thyroid Follicle Model

    Energy Technology Data Exchange (ETDEWEB)

    Taborda, A; Benabdallah, N; Desbree, A [Institut de Radioprotection et de Surete Nucleaire, Fontenay-aux-roses (France)

    2015-06-15

    Purpose: To perform a dosimetry study at the sub-cellular scale of Auger-electron emitter 99m-Tc using a mouse single thyroid cellular model to investigate the contribution of the 99m-Tc Auger-electrons to the absorbed dose and possible link to the thyroid stunning in in vivo experiments in mice, recently reported in literature. Methods: The simulation of S-values for Auger-electron emitting radionuclides was performed using both the recent MCNP6 software and the Geant4-DNA extension of the Geant4 toolkit. The dosimetric calculations were validated through comparison with results from literature, using a simple model of a single cell consisting of two concentric spheres of unit density water and for six Auger-electron emitting radionuclides. Furthermore, the S-values were calculated using a single thyroid follicle model for uniformly distributed 123-I and 125-I radionuclides and compared with published S-values. After validation, the simulation of the S-values was performed for the 99m-Tc radionuclide within the several mouse thyroid follicle cellular compartments, considering the radiative and non-radiative transitions of the 99m-Tc radiation spectrum. Results: The calculated S-values using MCNP6 are in good agreement with the results from literature, validating its use for the 99m-Tc S-values calculations. The most significant absorbed dose corresponds to the case where the radionuclide is uniformly distributed in the follicular cell’s nucleus, with a S-value of 7.8 mGy/disintegration, due mainly to the absorbed Auger-electrons. The results show that, at a sub-cellular scale, the emitted X-rays and gamma particles do not contribute significantly to the absorbed dose. Conclusion: In this work, MCNP6 was validated for dosimetric studies at the sub-cellular scale. It was shown that the contribution of the Auger-electrons to the absorbed dose is important at this scale compared to the emitted photons’ contribution and can’t be neglected. The obtained S

  8. The relation between Acid Volatile Sulfides (AVS) and metal accumulation in aquatic invertebrates: implications of feeding behavior and ecology.

    Science.gov (United States)

    De Jonge, Maarten; Blust, Ronny; Bervoets, Lieven

    2010-05-01

    The present study evaluates the relationship between Acid Volatile Sulfides (AVS) and metal accumulation in invertebrates with different feeding behavior and ecological preferences. Natural sediments, pore water and surface water, together with benthic and epibenthic invertebrates were sampled at 28 Flemish lowland rivers. Different metals as well as metal binding sediment characteristics including AVS were measured and multiple regression was used to study their relationship with accumulated metals in the invertebrates taxa. Bioaccumulation in the benthic taxa was primarily influenced by total metal concentrations in the sediment. Regarding the epibenthic taxa metal accumulation was mostly explained by the more bioavailable metal fractions in both the sediment and the water. AVS concentrations were generally better correlated with metal accumulation in the epibenthic invertebrates, rather than with the benthic taxa. Our results indicated that the relation between AVS and metal accumulation in aquatic invertebrates is highly dependent on feeding behavior and ecology. Copyright 2010 Elsevier Ltd. All rights reserved.

  9. Reactive oxygen species-related activities of nano-iron metal and nano-iron oxides.

    Science.gov (United States)

    Wu, Haohao; Yin, Jun-Jie; Wamer, Wayne G; Zeng, Mingyong; Lo, Y Martin

    2014-03-01

    Nano-iron metal and nano-iron oxides are among the most widely used engineered and naturally occurring nanostructures, and the increasing incidence of biological exposure to these nanostructures has raised concerns about their biotoxicity. Reactive oxygen species (ROS)-induced oxidative stress is one of the most accepted toxic mechanisms and, in the past decades, considerable efforts have been made to investigate the ROS-related activities of iron nanostructures. In this review, we summarize activities of nano-iron metal and nano-iron oxides in ROS-related redox processes, addressing in detail the known homogeneous and heterogeneous redox mechanisms involved in these processes, intrinsic ROS-related properties of iron nanostructures (chemical composition, particle size, and crystalline phase), and ROS-related bio-microenvironmental factors, including physiological pH and buffers, biogenic reducing agents, and other organic substances. Copyright © 2014. Published by Elsevier B.V.

  10. Heavy Metal Content in Chilean Fish Related to Habitat Use, Tissue Type and River of Origin.

    Science.gov (United States)

    Copaja, S V; Pérez, C A; Vega-Retter, C; Véliz, D

    2017-12-01

    In this study, we analyze the concentration of ten metals in two freshwater fish-the benthic catfish Trichomycterus areolatus and the limnetic silverside Basilichthys microlepidotus-in order to detect possible accumulation differences related to fish habitat (benthic or pelagic), tissue type (gill, liver and muscle), and the river of origin (four different rivers) in central Chile. The MANOVA performed with all variables and metals, revealed independent effects of fish, tissue and river. In the case of the fish factor, Cu, Cr, Mo and Zn showed statistically higher concentrations in catfish compared with silverside for all tissues and in all rivers (p food sources and respiration.

  11. Liquid metal embrittlement. From basic concepts to recent results related to structural materials for liquid metal spallation targets

    International Nuclear Information System (INIS)

    Gorse, D.; Goryachev, S.; Auger, T.

    2003-01-01

    At first, the basic features of LME are recalled (definition, characteristics, embrittling couples), together with classical experimental features and open questions. Then, a review of a few very recent results obtained on classical embrittling couples but using new powerful investigation techniques developed in France is proposed. Second we define LMC. The 'LME-LMC' correlation is postulated. Then we concentrate on the LME-LMC problem related to the build-up of the Liquid Metal Spallation target in the frame of the MEGAPIE project. The Russian expertise on LME is briefly mentioned. Then we present some results obtained in the frame of the Groupement de Recherche' GEDEON, focusing on steel grade T91 in contact with lead and lead-bismuth eutectic, in agreement with Russian literature. (author)

  12. Metal-insulator transition and superconductivity in heavily boron-doped diamond and related materials

    Energy Technology Data Exchange (ETDEWEB)

    Achatz, Philipp

    2009-05-15

    During this PhD project, the metal-insulator transition and superconductivity of highly boron-doped single crystal diamond and related materials have been investigated. The critical boron concentration n{sub c} for the metal-insulator transition was found to be the same as for the normal-superconductor transition. All metallic samples have been found to be superconducting and we were able to link the occurence of superconductivity to the proximity to the metal-insulator transition. For this purpose, a scaling law approach based on low temperature transport was proposed. Furthermore, we tried to study the nature of the superconductivity in highly boron doped single crystal diamond. Raman spectroscopy measurements on the isotopically substituted series suggest that the feature occuring at low wavenumbers ({approx} 500 cm{sup -1}) is the A1g vibrational mode associated with boron dimers. Usual Hall effect measurements yielded a puzzling situation in metallic boron-doped diamond samples, leading to carrier concentrations up to a factor 10 higher than the boron concentration determined by secondary ion mass spectroscopy (SIMS). The low temperature transport follows the one expected for a granular metal or insulator, depending on the interplay of intergranular and intragranular (tunneling) conductance. The metal-insulator transition takes place at a critical conductance g{sub c}. The granularity also influences significantly the superconducting properties by introducing the superconducting gap {delta} in the grain and Josephson coupling J between superconducting grains. A peak in magnetoresistance is observed which can be explained by superconducting fluctuations and the granularity of the system. Additionally we studied the low temperature transport of boron-doped Si samples grown by gas immersion laser doping, some of which yielded a superconducting transition at very low temperatures. Furthermore, preliminary results on the LO-phonon-plasmon coupling are shown for the

  13. Metal-insulator transition and superconductivity in heavily boron-doped diamond and related materials

    International Nuclear Information System (INIS)

    Achatz, Philipp

    2009-01-01

    During this PhD project, the metal-insulator transition and superconductivity of highly boron-doped single crystal diamond and related materials have been investigated. The critical boron concentration n c for the metal-insulator transition was found to be the same as for the normal-superconductor transition. All metallic samples have been found to be superconducting and we were able to link the occurence of superconductivity to the proximity to the metal-insulator transition. For this purpose, a scaling law approach based on low temperature transport was proposed. Furthermore, we tried to study the nature of the superconductivity in highly boron doped single crystal diamond. Raman spectroscopy measurements on the isotopically substituted series suggest that the feature occuring at low wavenumbers (∼ 500 cm -1 ) is the A1g vibrational mode associated with boron dimers. Usual Hall effect measurements yielded a puzzling situation in metallic boron-doped diamond samples, leading to carrier concentrations up to a factor 10 higher than the boron concentration determined by secondary ion mass spectroscopy (SIMS). The low temperature transport follows the one expected for a granular metal or insulator, depending on the interplay of intergranular and intragranular (tunneling) conductance. The metal-insulator transition takes place at a critical conductance g c . The granularity also influences significantly the superconducting properties by introducing the superconducting gap Δ in the grain and Josephson coupling J between superconducting grains. A peak in magnetoresistance is observed which can be explained by superconducting fluctuations and the granularity of the system. Additionally we studied the low temperature transport of boron-doped Si samples grown by gas immersion laser doping, some of which yielded a superconducting transition at very low temperatures. Furthermore, preliminary results on the LO-phonon-plasmon coupling are shown for the first time in aluminum

  14. Mitochondrial Dysfunctions and Altered Metals Homeostasis: New Weapons to Counteract HCV-Related Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Mario Arciello

    2013-01-01

    Full Text Available The hepatitis C virus (HCV infection produces several pathological effects in host organism through a wide number of molecular/metabolic pathways. Today it is worldwide accepted that oxidative stress actively participates in HCV pathology, even if the antioxidant therapies adopted until now were scarcely effective. HCV causes oxidative stress by a variety of processes, such as activation of prooxidant enzymes, weakening of antioxidant defenses, organelle damage, and metals unbalance. A focal point, in HCV-related oxidative stress onset, is the mitochondrial failure. These organelles, known to be the “power plants” of cells, have a central role in energy production, metabolism, and metals homeostasis, mainly copper and iron. Furthermore, mitochondria are direct viral targets, because many HCV proteins associate with them. They are the main intracellular free radicals producers and targets. Mitochondrial dysfunctions play a key role in the metal imbalance. This event, today overlooked, is involved in oxidative stress exacerbation and may play a role in HCV life cycle. In this review, we summarize the role of mitochondria and metals in HCV-related oxidative stress, highlighting the need to consider their deregulation in the HCV-related liver damage and in the antiviral management of patients.

  15. A NEW SCALING RELATION FOR H II REGIONS IN SPIRAL GALAXIES: UNVEILING THE TRUE NATURE OF THE MASS-METALLICITY RELATION

    Energy Technology Data Exchange (ETDEWEB)

    Rosales-Ortega, F. F.; Diaz, A. I. [Departamento de Fisica Teorica, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Sanchez, S. F.; Iglesias-Paramo, J.; Vilchez, J. M.; Mast, D. [Instituto de Astrofisica de Andalucia (CSIC), Camino Bajo de Huetor s/n, Aptdo. 3004, E-18080 Granada (Spain); Bland-Hawthorn, J. [Sydney Institute for Astronomy, School of Physics A28, University of Sydney, NSW 2006 (Australia); Husemann, B., E-mail: frosales@cantab.net [Leibniz-Institut fuer Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany)

    2012-09-10

    We demonstrate the existence of a local mass, metallicity, star formation relation using spatially resolved optical spectroscopy of H II regions in the local universe. One of the projections of this distribution-the local mass-metallicity relation-extends over a wide range in this parameter space: three orders of magnitude in mass and a factor of eight in metallicity. We explain the new relation as the combined effect of the differential distributions of mass and metallicity in the disks of galaxies, and a selective star formation efficiency. We use this local relation to reproduce-with a noticeable agreement-the mass-metallicity relation seen in galaxies, and conclude that the latter is a scale-up integrated effect of a local relation, supporting the inside-out growth and downsizing scenarios of galaxy evolution.

  16. On the behavior of Bronsted-Evans-Polanyi Relations for Transition Metal Oxides

    Energy Technology Data Exchange (ETDEWEB)

    Vojvodic, Aleksandra

    2011-08-22

    Versatile Broensted-Evans-Polanyi (BEP) relations are found from density functional theory for a wide range of transition metal oxides including rutiles and perovskites. For oxides, the relation depends on the type of oxide, the active site and the dissociating molecule. The slope of the BEP relation is strongly coupled to the adsorbate geometry in the transition state. If it is final state-like the dissociative chemisorption energy can be considered as a descriptor for the dissociation. If it is initial state-like, on the other hand, the dissociative chemisorption energy is not suitable as descriptor for the dissociation. Dissociation of molecules with strong intramolecular bonds belong to the former and molecules with weak intramolecular bonds to the latter group. We show, for the prototype system La-perovskites, that there is a 'cyclic' behavior in the transition state characteristics upon change of the active transition metal of the oxide.

  17. The mass-metallicity-star formation rate relation under the STARLIGHT microscope

    Science.gov (United States)

    Schlickmann, M.; Vale Asari, N.; Cid Fernandes, R.; Stasińska, G.

    2014-10-01

    The correlation between stellar mass and gas-phase oxygen abundance (M-Z relation) has been known for decades. The slope and scatter of this trend is strongly dependent on galaxy evolution: Chemical enrichment in a galaxy is driven by its star formation history, which in turn depends on its secular evolution and interaction with other galaxies and intergalactic gas. In last couple of years, the M-Z relation has been studied as a function of a third parameter: the recent star formation rate (SFR) as calibrated by the Hα luminosity, which traces stars formed in the last 10 Myr. This mass-metallicity-SFR relation has been reported to be very tight. This result puts strong constraints on galaxy evolution models in low and high redshifts, informing which models of infall and outflow of gas are acceptable. We explore the mass-metallicity-SFR relation in light of the SDSS-STARLIGHT database put together by our group. We find that we recover similar results as the ones reported by authors who use the MPA/JHU catalogue. We also present some preliminary results exploring the mass-metallicity-SFR relation in a more detailed fashion: starlight recovers a galaxy's full star formation history, and not only its recent SFR.

  18. Origin of metallic Fe-Ni in Renazzo and related chondrites

    Science.gov (United States)

    Lee, Min S.; Rubin, Alan E.; Wasson, John T.

    1992-01-01

    To assess the formation of metallic Fe-Ni in Renazzo and related chondrites, Ni and Co zoning profiles in metallic Fe-Ni are determined from different petrographic sites (chondrule interiors, chondrule margins, chondrule rims, and matrix) in Renazzo, Al Rais, and the related chondrite, MacAlpine Hills 87320. Metal from chondrule interiors shows flat Ni and Co concentrations and profiles, moderately large grain-to-grain compositional variations (even with chondrules), and generally high Ni and Co. Nickel concentrations extend above the kamacite stability limit; etching such 'martensite' shows high-Ni domains in some cases, but observed Ni concentrations do not exceed 190 mg/g. Metal from chondrule margins adjacent to matrix shows convex Ni and Co zoning profiles; the highest Ni and Co concentrations are at grain centers, although the mean central Ni and Co concentrations in margin grains are much lower than those from chondrule interiors; the remainder are convex. The low Co and Ni contents at the edge of grains in chondrule margins are interpreted to reflect dilution by Fe produced by FeO reduction.

  19. Sex- and age-related variation in metal content of penguin feathers.

    Science.gov (United States)

    Squadrone, Stefania; Abete, Maria Cesarina; Brizio, Paola; Monaco, Gabriella; Colussi, Silvia; Biolatti, Cristina; Modesto, Paola; Acutis, Pier Luigi; Pessani, Daniela; Favaro, Livio

    2016-03-01

    The presence of xenobiotics, such as metals, in ecosystems is concerning due to their durability and they pose a threat to the health and life of organisms. Moreover, mercury can biomagnify in many marine food chains and, therefore, organisms at higher trophic levels can be adversely impacted. Although feathers have been used extensively as a bio-monitoring tool, only a few studies have addressed the effect of both age and sex on metal accumulation. In this study, the concentrations of trace elements were determined in the feathers of all members of a captive colony of African Penguins (Spheniscus demersus) housed in a zoological facility in Italy. Tests were performed by inductively coupled plasma-mass spectrometry to detect aluminum, arsenic, cadmium, cobalt, chromium, copper, iron, manganese, nickel, lead, selenium, tin, vanadium, and zinc. Mercury was detected by a direct mercury analyzer. Sexing was performed by a molecular approach based on analyzing the chromo-helicase-DNA-binding1 gene, located on the sex chromosomes. Sex- and age-related differences were studied in order to investigate the different patterns of metal bioaccumulation between male and female individuals and between adults and juveniles. Juvenile females had significantly higher arsenic levels than males, while selenium levels increased significantly with age in both sexes. Penguins kept in controlled environments-given that diet and habitat are under strict control-represent a unique opportunity to determine if and how metal bioaccumulation is related to sex and age.

  20. Infant and mother related outcomes from exposure to metals with endocrine disrupting properties during pregnancy

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, A. [Interdisciplinary School of Health Sciences, University of Ottawa, Ottawa (Canada); Kumarathasan, P. [Environmental Health Science and Research Bureau, Health Canada, Ottawa (Canada); Gomes, J., E-mail: jgomes@uottawa.ca [Interdisciplinary School of Health Sciences, University of Ottawa, Ottawa (Canada); McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa (Canada)

    2016-11-01

    Background: Endocrine-related adverse health effects from exposure to heavy metals such as lead, arsenic, cadmium, and mercury are yet to be adequately described. The purpose of this review was to gain insight into maternal exposure to heavy metals, and to identify potential endocrine-related adverse health effects in the mother and the infant. Methods: Relevant databases were searched for original research reports and a total of 46 articles were retained for scrutiny. Required data was extracted from these studies and their methodology was assessed. Results: Impaired fetal growth was observed from exposure to all endocrine disrupting metals, while exposure to lead and arsenic were associated with spontaneous abortion, stillbirth and neonatal deaths. Maternal exposure to arsenic was associated with impaired glucose tolerance in these mothers. Conclusion: Impaired fetal growth, fetal loss, and neonatal deaths were significantly associated with heavy metals exposure during pregnancy; however, hypertension and gestational diabetes require further investigation. - Highlights: • Low and high dose exposure to lead was associated with low birth weight, preterm birth, stillbirths, spontaneous abortions and hypertension. • Exposure to arsenic was associated with fetal loss, stillbirths and spontaneous abortions. • Exposure to cadmium was associated with low birth weight. • Exposure to mercury was associated with spontaneous abortions and neurotoxic effects. • Exposure to copper was associated with low birth weight and spontaneous abortions and exposure to zinc was associated with low birth weight.

  1. Infant and mother related outcomes from exposure to metals with endocrine disrupting properties during pregnancy

    International Nuclear Information System (INIS)

    Rahman, A.; Kumarathasan, P.; Gomes, J.

    2016-01-01

    Background: Endocrine-related adverse health effects from exposure to heavy metals such as lead, arsenic, cadmium, and mercury are yet to be adequately described. The purpose of this review was to gain insight into maternal exposure to heavy metals, and to identify potential endocrine-related adverse health effects in the mother and the infant. Methods: Relevant databases were searched for original research reports and a total of 46 articles were retained for scrutiny. Required data was extracted from these studies and their methodology was assessed. Results: Impaired fetal growth was observed from exposure to all endocrine disrupting metals, while exposure to lead and arsenic were associated with spontaneous abortion, stillbirth and neonatal deaths. Maternal exposure to arsenic was associated with impaired glucose tolerance in these mothers. Conclusion: Impaired fetal growth, fetal loss, and neonatal deaths were significantly associated with heavy metals exposure during pregnancy; however, hypertension and gestational diabetes require further investigation. - Highlights: • Low and high dose exposure to lead was associated with low birth weight, preterm birth, stillbirths, spontaneous abortions and hypertension. • Exposure to arsenic was associated with fetal loss, stillbirths and spontaneous abortions. • Exposure to cadmium was associated with low birth weight. • Exposure to mercury was associated with spontaneous abortions and neurotoxic effects. • Exposure to copper was associated with low birth weight and spontaneous abortions and exposure to zinc was associated with low birth weight.

  2. A NEW SCALING RELATION FOR H II REGIONS IN SPIRAL GALAXIES: UNVEILING THE TRUE NATURE OF THE MASS-METALLICITY RELATION

    International Nuclear Information System (INIS)

    Rosales-Ortega, F. F.; Díaz, A. I.; Sánchez, S. F.; Iglesias-Páramo, J.; Vílchez, J. M.; Mast, D.; Bland-Hawthorn, J.; Husemann, B.

    2012-01-01

    We demonstrate the existence of a local mass, metallicity, star formation relation using spatially resolved optical spectroscopy of H II regions in the local universe. One of the projections of this distribution—the local mass-metallicity relation—extends over a wide range in this parameter space: three orders of magnitude in mass and a factor of eight in metallicity. We explain the new relation as the combined effect of the differential distributions of mass and metallicity in the disks of galaxies, and a selective star formation efficiency. We use this local relation to reproduce—with a noticeable agreement—the mass-metallicity relation seen in galaxies, and conclude that the latter is a scale-up integrated effect of a local relation, supporting the inside-out growth and downsizing scenarios of galaxy evolution.

  3. Trace metals in Antarctica related to climate change and increasing human impact.

    Science.gov (United States)

    Bargagli, R

    2000-01-01

    in most samples of atmospheric particulates, snow, ice, soils, and marine sediments from Antarctica can be taken as global background levels. Comparison between the results of trace element surveys in marine waters of the Southern Ocean and in other seas is practically impossible. The upwelling or subduction of water masses, the seasonality in ice cover and in phytoplankton biomass, the low fallout of atmospheric dust, and many other peculiar characteristics of the Southern Ocean make concentrations of trace metals in surface waters quite variable in space and time. The depletion of nutrients in surface waters, which is a regular feature of many marine environments, rarely occurs in the Southern Ocean. Waters in some regions are characterized by very low concentrations of Fe and Mn, whereas in others the content of Cd is relatively high at the beginning of summer and may decrease about one order of magnitude during the phytoplankton bloom. Although in most Antarctic coastal ecosystems the input of metals from geochemical and anthropogenic sources and from long-range transport is negligible, concentrations of Cd in the waters and biota may be higher than in waters and related species of organisms from polluted coastal areas. Like the Southern Ocean, Antarctic lakes have many peculiar characteristics. They are often perennially ice covered and without outlet, and their water, which is gained only from short-term melting of snow and glaciers in summer, is lost mainly by sublimation of surface ice. Several lakes are distinctly stratified: the water under the ice may be cool, rich in oxygen, and among the cleanest and clearest of natural waters, whereas water near the bottom becomes anoxic, tepid, and richer in major and trace elements. Considering the specificity of Antarctic environments, to evaluate the extent and consequences of global changes and increasing human activities in Antarctica itself, research on the biogeochemistry of trace metals and monitoring programs

  4. Cytotoxic mechanism related to dihydrolipoamide dehydrogenase in Leydig cells exposed to heavy metals

    International Nuclear Information System (INIS)

    Ji, Xunmin; Li, Zhiliang; Chen, Hongxia; Li, Junqi; Tian, Huajian; Li, Zengli; Gao, Xuejuan; Xiang, Qi; Su, Zhijian; Huang, Yadong; Zhang, Qihao

    2015-01-01

    Heavy metals are common environmental toxicants with adverse effects on steroid biosynthesis. The importance of mitochondria has been recognized in cytotoxic mechanism of heavy metals on Leydig cells these years. But it is still poorly known. Our previous study reported that dihydrolipoamide dehydrogenase (DLD) located on the mitochondria was significantly decreased in Leydig cells exposed to cadmium, which suggested that DLD might be involved in the cytotoxic effects. Therefore, the altered expression of DLD was validated in rats and R2C cells exposed to cadmium, manganese and lead, and the role of DLD in the steroid synthesis pathway cAMP/PKA-ERK1/2 was investigated in this study. With a low expression of DLD, heavy metals dramatically reduced the levels of steroid hormone by inhibiting the activation of cAMP/PKA, PKC signaling pathway and the steroidogenic enzymes StAR, CYP11A1 and 3β-HSD. After knockdown of DLD in R2C cells, progesterone synthesis was reduced by 40%, and the intracellular concentration of cAMP, protein expression of StAR, 3β-HSD, PKA, and the phosphorylation of ERK1/2 were also decreased. These results highlight that DLD is down-regulation and related to steroid biosynthesis in Leyig cells exposed to heavy metals; cAMP/PKA act as downstream effector molecules of DLD, which activate phosphorylation of ERK1/2 to initiate the steroidogenesis

  5. Surface density: a new parameter in the fundamental metallicity relation of star-forming galaxies

    Science.gov (United States)

    Hashimoto, Tetsuya; Goto, Tomotsugu; Momose, Rieko

    2018-04-01

    Star-forming galaxies display a close relation among stellar mass, metallicity, and star formation rate (or molecular-gas mass). This is known as the fundamental metallicity relation (FMR) (or molecular-gas FMR), and it has a profound implication on models of galaxy evolution. However, there still remains a significant residual scatter around the FMR. We show here that a fourth parameter, the surface density of stellar mass, reduces the dispersion around the molecular-gas FMR. In a principal component analysis of 29 physical parameters of 41 338 star-forming galaxies, the surface density of stellar mass is found to be the fourth most important parameter. The new 4D fundamental relation forms a tighter hypersurface that reduces the metallicity dispersion to 50 per cent of that of the molecular-gas FMR. We suggest that future analyses and models of galaxy evolution should consider the FMR in a 4D space that includes surface density. The dilution time-scale of gas inflow and the star-formation efficiency could explain the observational dependence on surface density of stellar mass.

  6. On the determination of representative stress–strain relation of metallic materials using instrumented indentation

    International Nuclear Information System (INIS)

    Fu, Kunkun; Chang, Li; Zheng, Bailin; Tang, Youhong; Wang, Hongjian

    2015-01-01

    Highlights: • A method to convert indentation load–depth curve into representative stress–strain curve is presented. • Representative stress–strain curves of six metals are obtained using finite element analysis. • Different representative strain definitions are compared using finite element method. • Representative stress–strain curve of molybdenum films is obtained by nanoindentation tests. - Abstract: In this study, attempts have been made to estimate the representative stress–strain relation of metallic materials from indentation tests using an iterative method. Finite element analysis was performed to validate the method. The results showed that representative stress–strain relations of metallic materials using the present method were in a good agreement with those from tensile tests. Further, this method was extended to predict representative stress–strain relation of ultra-thin molybdenum films with a thickness of 485 nm using nanoindentation. Yielding strength and strain hardening exponent of the films were therefore obtained, which showed a good agreement with the published data

  7. Heavy metals content in degraded agricultural soils of a mountain region related to soil properties

    Science.gov (United States)

    Navarro-Pedreño, José; Belén Almendro-Candel, María; Gómez, Ignacio; Jordán, Manuel M.; Bech, Jaume; Zorpas, Antonis

    2017-04-01

    Agriculture has been practiced for long time in Mediterranean regions. Intensive agriculture and irrigation have developed mainly in the valleys and coastal areas. In the mountainous areas, dry farming has been practiced for centuries. Soils have been fertilized using mainly organic amendments. Plants extracted nutrients and other elements like heavy metals presented in soils and agricultural practices modified soil properties that could favor the presence of heavy metals. In this work, it has been checked the content of heavy metals in 100 agricultural soils samples of the NorthWest area of the province of Alicante (Spain) which has been long cultivated with cereals and olive trees, and now soils are abandoned and degraded because of the low agricultural yields. European policy has the aim to improve the sustainable agriculture and recover landscapes of mountain regions. So that, it is important to check the state of the soils (Marques et al. 2007). Soils samples (arable layer) were analyzed determining: pH (1:5, w/v, water extract), equivalent calcium carbonate content, organic matter by Walkley-Black method (Nelson and Sommers 1996), micronutrients (Cu, Fe, Mn, Zn) extracted with DTPA (Lindsay and Norvell, 1978) and measured by atomic absorption spectrometry, and total content of metals (Cd, Cr, Ni, Pb) measured in soil samples after microwave acid digestion (Moral et al. 1996), quantifying the content of metals by ICP analysis. The correlation between soil properties and metals. The results indicated that pH and carbonates are the most important properties of these soils correlated with the metals (both micronutrients and heavy metals). The available micronutrients (all of them) are close correlated with the pH and carbonates in soils. Moreover, heavy metals like Pb and Ni are related to available Mn and Zn. Keywords: pH, carbonates, heavy metals, abandoned soils. References: Lindsay,W.L., andW.A. Norvell. 1978. "Development of a DTPA Soil Test for Zinc, Iron

  8. Relating environmental availability to bioavailability: soil-type-dependent metal accumulation in the oligochaete Eisenia andrei.

    Science.gov (United States)

    Peijnenburg, W J; Baerselman, R; de Groot, A C; Jager, T; Posthuma, L; Van Veen, R P

    1999-11-01

    Body residues are often better estimates of the amount of a chemical at the sites of toxic action in an organism than ambient soil concentrations, because bioavailability differences among soils are explicitly taken into account in considerations of body residues. Often, however, insufficient attention is paid to the rate and extent at which tissue concentrations respond to soil concentrations and soil characteristics. In this contribution the impact of soil characteristics on the environmental bioavailability of heavy metals for the oligochaete worm Eisenia andrei is reported. Uptake of As, Cd, Cr, Cu, Ni, Pb, and Zn in 20 Dutch field soils and in OECD artificial soil was quantified as a function of time. Internal metal concentrations varied less than the corresponding external levels. Metal uptake and elimination were both metal- and species-dependent. Worms typically attained steady-state concentrations rapidly for Cr, Cu, Ni, and Zn. Internal concentrations similar to those in the cultivation medium, linearly increasing body concentrations, or steady-state internal concentrations well above those in the cultivation medium were found for As, Cd, and Pb. Multivariate expressions were derived to describe uptake rate constants, steady-state concentrations, and bioaccumulation factors as a function of soil characteristics. Soil acidity is the most important solid-phase characteristic modulating the availability of As, Cd, and Pb. Although additional semimechanistic calculations yielded evidence of pore-water-related uptake of Cd and Pb modulated by competition between H(+) and metal ions at the active sites of the membranes, the findings for Cr, Cu, Ni, and Zn point to additional influences, among which is probably regulation. Copyright 1999 Academic Press.

  9. Nuclear methods applied for studies of contact phenomena in metal-fluid media and between metallic components in relative motion

    International Nuclear Information System (INIS)

    Racolta, P.M.; Popa-Simil, L.; Voiculescu, Dana; Muntele, C. I.

    1997-01-01

    The two main goals of this research project were: establishing of an activation methodology for metallic structures using accelerated beams obtained at our cyclotron and adapting the spectrometric analysis methods of the gamma radiations for corrosion level determinations. The developed methods, including the calibration (relations between the radioactivity level and the thickness of removed layer due to corrosion), were based on the remnant radioactivity measuring method. The experiments were focused on a proper selection of the nuclear reaction to be utilised for measurements, depending on the type of metallic alloys investigated. This study also consisted of optimizing the irradiation (particle, energy and dose) and cooling time so as to obtain a measuring sensitivity of 0.1-1μm for Fe, Ti, V, Cr, Cu, Mo based alloys. A portable two-channel γ-spectrometric installation was adapted to a customer's corrosion testing stand. Corrosion levels of a Romanian-made injection pump working with different types of Diesel oils and Diesel oil + special additives + water mixtures were determined. The nuclear reactions used were 56 Fe (p,n) 56 Co and 56 Fe (d,n) 57 Co. A selected area of the pump's piston was activated up to 30 μm. The testing programme was made for 300 h working times on the test stand; corrosion levels of approx. 0.3 μm were observed. In cooperation with a group from Tribology Laboratory from the Bucharest Technical University, Ti-coated pallets of a water pump were tested in their near real working environment - salty and sandy water. The 48 Ti (p,n) 48 V nuclear reaction was used for labelling a Ti thickness up to 50 μm. In this experiment, the main interest was to determine the minimum detectable corroded thickness by this radiotracer - based method. Our measurements showed that sensitivities of 0.05 - 1 μm can be achieved. In 1996, in cooperation with the National Institute for Thermal Engines, the wear of the piston ring - cylinder jacket friction

  10. The relation between Acid Volatile Sulfides (AVS) and metal accumulation in aquatic invertebrates: Implications of feeding behavior and ecology

    International Nuclear Information System (INIS)

    De Jonge, Maarten; Blust, Ronny; Bervoets, Lieven

    2010-01-01

    The present study evaluates the relationship between Acid Volatile Sulfides (AVS) and metal accumulation in invertebrates with different feeding behavior and ecological preferences. Natural sediments, pore water and surface water, together with benthic and epibenthic invertebrates were sampled at 28 Flemish lowland rivers. Different metals as well as metal binding sediment characteristics including AVS were measured and multiple regression was used to study their relationship with accumulated metals in the invertebrates taxa. Bioaccumulation in the benthic taxa was primarily influenced by total metal concentrations in the sediment. Regarding the epibenthic taxa metal accumulation was mostly explained by the more bioavailable metal fractions in both the sediment and the water. AVS concentrations were generally better correlated with metal accumulation in the epibenthic invertebrates, rather than with the benthic taxa. Our results indicated that the relation between AVS and metal accumulation in aquatic invertebrates is highly dependent on feeding behavior and ecology. - The relation between AVS and metal accumulation in aquatic invertebrates is highly dependent on feeding behavior and ecology.

  11. Probing galaxy growth through metallicity scaling relations over the past 12 Gyr of cosmic history

    Science.gov (United States)

    Sanders, Ryan; MOSDEF team

    2018-01-01

    A primary goal of galaxy evolution studies is to understand the processes governing the growth of the baryonic content of galaxies over cosmic history. Observations of galaxy metallicity scaling relations and their evolution with redshift, in combination with chemical evolution models, provide unique insight into the interplay between star formation, gas accretion, and feedback/outflows. I present measurements of the stellar mass-gas phase metallicity relation and its evolution over the past 12 Gyr from z~0 to z~3.5, utilizing data from the Mosfire Deep Evolution Field survey that uniquely provides rest-frame optical spectra of >1000 uniformly-selected galaxies at z=1.3-3.8. We find evolution towards lower metallicity at fixed stellar mass with increasing redshift that is consistent with current cosmological simulations including chemical evolution, with a large evolution of ~0.3 dex from z~0 to z~2.5 and minor evolution of 2, and discuss the potential of current and next-generation observational facilities to obtain statistical auroral-line samples at high redshifts.

  12. Species- and age-related variation in metal exposure and accumulation of two passerine bird species

    Energy Technology Data Exchange (ETDEWEB)

    Berglund, A.M.M., E-mail: asa.berglund@emg.umu.se [Section of Ecology, 20014 University of Turku (Finland); Koivula, M.J.; Eeva, T. [Section of Ecology, 20014 University of Turku (Finland)

    2011-10-15

    We measured the concentration of several elements (arsenic [As], calcium [Ca], cadmium [Cd], copper [Cu], nickel [Ni], lead [Pb], selenium [Se] and zinc [Zn]) in adult and nestling pied flycatchers (Ficedula hypoleuca) and great tits (Parus major) at different distances to a Cu-Ni smelter in 2009. Feces of nestlings generally failed to correspond with internal element concentrations but reflected the pollution exposure, indicating an increased stress by removal of excess metals. The uptake of Cu and Ni were regulated, but As, Cd, Pb and Se accumulated in liver tissue. Pied flycatchers had generally higher element concentrations than great tits. The higher accumulation of As and Pb in pied flycatcher livers was explained by a more efficient absorption, whereas the higher Cd concentration was primarily due to different intake of food items. Age-related differences occurred between the two species, though both Cd and Se accumulated with age. - Highlights: > We measured metal concentrations in feces and livers of two passerine species. > We examined species- and age-related differences in polluted environments. > Feces was evaluated as a useful non-destructive measure of increased stress. > Generally pied flycatchers accumulated higher concentrations than great tits. > Cadmium and selenium accumulated with age in both species. - Accumulation of metals in liver of two insectivorous passerines reflects inter-specific differences in diet, absorption rate and physiological requirements.

  13. Species- and age-related variation in metal exposure and accumulation of two passerine bird species

    International Nuclear Information System (INIS)

    Berglund, A.M.M.; Koivula, M.J.; Eeva, T.

    2011-01-01

    We measured the concentration of several elements (arsenic [As], calcium [Ca], cadmium [Cd], copper [Cu], nickel [Ni], lead [Pb], selenium [Se] and zinc [Zn]) in adult and nestling pied flycatchers (Ficedula hypoleuca) and great tits (Parus major) at different distances to a Cu-Ni smelter in 2009. Feces of nestlings generally failed to correspond with internal element concentrations but reflected the pollution exposure, indicating an increased stress by removal of excess metals. The uptake of Cu and Ni were regulated, but As, Cd, Pb and Se accumulated in liver tissue. Pied flycatchers had generally higher element concentrations than great tits. The higher accumulation of As and Pb in pied flycatcher livers was explained by a more efficient absorption, whereas the higher Cd concentration was primarily due to different intake of food items. Age-related differences occurred between the two species, though both Cd and Se accumulated with age. - Highlights: → We measured metal concentrations in feces and livers of two passerine species. → We examined species- and age-related differences in polluted environments. → Feces was evaluated as a useful non-destructive measure of increased stress. → Generally pied flycatchers accumulated higher concentrations than great tits. → Cadmium and selenium accumulated with age in both species. - Accumulation of metals in liver of two insectivorous passerines reflects inter-specific differences in diet, absorption rate and physiological requirements.

  14. The alteration of oxidation and related properties of metals by ion implantation

    International Nuclear Information System (INIS)

    Dearnaley, G.

    1981-01-01

    A review is given of the various ways in which ion implanted additives can affect the thermal oxidation of metals, for example by blocking diffusion paths for ions, by catalytic effects or by altering the plasticity of the oxide. The versatility of the process has already proved useful in the study of oxidation mechanisms. Ways of achieving a long-lasting protection are discussed in relation to the dominant mechanisms of oxidation inhibition. In many practical applications at elevated temperatures oxidation and mechanical stresses co-exist. In steels the process of oxidative wear is important under conditions of poor lubrication and implanted metallic ions have been shown to be effective. In titanium alloys fatigue cracks probably initiate at dislocation sites at which oxidation proceeds most rapidly, and hence the same implanted species can improve both types of behaviour. Successful implantation treatments for fretting fatigue in titanium and a corrosion-erosion problem in steel are described. (orig.)

  15. THE KENNICUTT–SCHMIDT RELATION IN EXTREMELY METAL-POOR DWARF GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Filho, M. E.; Almeida, J. Sánchez; Muñoz-Tuñón, C. [Instituto Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Amorín, R. [National Institute for Astrophysics, Astronomical Observatory of Rome, Via Frascati 33, I-00040 Monteporzio Catone (Rome) (Italy); Elmegreen, B. G. [IBM, T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States); Elmegreen, D. M., E-mail: mfilho@astro.up.pt [Department of Physics and Astronomy, Vassar College, Poughkeepsie, NY 12604 (United States)

    2016-04-01

    The Kennicutt–Schmidt (KS) relation between the gas mass and star formation rate (SFR) describes the star formation regulation in disk galaxies. It is a function of gas metallicity, but the low-metallicity regime of the KS diagram is poorly sampled. We have analyzed data for a representative set of extremely metal-poor galaxies (XMPs), as well as auxiliary data, and compared these to empirical and theoretical predictions. The majority of the XMPs possess high specific SFRs, similar to high-redshift star-forming galaxies. On the KS plot, the XMP H i data occupy the same region as dwarfs and extend the relation for low surface brightness galaxies. Considering the H i gas alone, a considerable fraction of the XMPs already fall off the KS law. Significant quantities of “dark” H{sub 2} mass (i.e., not traced by CO) would imply that XMPs possess low star formation efficiencies (SFE{sub gas}). Low SFE{sub gas} in XMPs may be the result of the metal-poor nature of the H i gas. Alternatively, the H i reservoir may be largely inert, the star formation being dominated by cosmological accretion. Time lags between gas accretion and star formation may also reduce the apparent SFE{sub gas}, as may galaxy winds, which can expel most of the gas into the intergalactic medium. Hence, on global scales, XMPs could be H i-dominated, high-specific-SFR (≳10{sup −10} yr{sup −1}), low-SFE{sub gas} (≲10{sup −9} yr{sup −1}) systems, in which the total H i mass is likely not a good predictor of the total H{sub 2} mass, nor of the SFR.

  16. Assessment of Trace Metals in Soil, Vegetation and Rodents in Relation to Metal Mining Activities in an Arid Environment.

    Science.gov (United States)

    Méndez-Rodríguez, Lia C; Alvarez-Castañeda, Sergio Ticul

    2016-07-01

    Areas where abandoned metal-extraction mines are located contain large quantities of mineral wastes derived from environmentally unsafe mining practices. These wastes contain many pollutants, such as heavy metals, which could be released to the environment through weathering and leaching, hence becoming an important source of environmental metal pollution. This study evaluates differences in the levels of lead, iron, nickel, manganese, copper and cadmium in rodents sharing the same type of diet under different microhabitat use in arid areas with past mining activities. Samples of soil, roots, branches and seeds of Palo Adán (Fouquieria diguetii) and specimens of two rodent species (Chaetodipus arenarius and C. spinatus) were collected in areas with impact from past metal mining activities as well as from areas with no mining impact. Both rodent species mirrored nickel and iron levels in soil and seeds, as well as lead levels in soil; however, C. arenarius accumulated higher levels of manganese, copper and cadmium.

  17. The mass-metallicity relations for gas and stars in star-forming galaxies: strong outflow versus variable IMF

    Science.gov (United States)

    Lian, Jianhui; Thomas, Daniel; Maraston, Claudia; Goddard, Daniel; Comparat, Johan; Gonzalez-Perez, Violeta; Ventura, Paolo

    2018-02-01

    We investigate the mass-metallicity relations for the gaseous (MZRgas) and stellar components (MZRstar) of local star-forming galaxies based on a representative sample from Sloan Digital Sky Survey Data Release 12. The mass-weighted average stellar metallicities are systematically lower than the gas metallicities. This difference in metallicity increases towards galaxies with lower masses and reaches 0.4-0.8 dex at 109 M⊙ (depending on the gas metallicity calibration). As a result, the MZRstar is much steeper than the MZRgas. The much lower metallicities in stars compared to the gas in low-mass galaxies imply dramatic metallicity evolution with suppressed metal enrichment at early times. The aim of this paper is to explain the observed large difference in gas and stellar metallicity and to infer the origin of the mass-metallicity relations. To this end we develop a galactic chemical evolution model accounting for star formation, gas inflow and outflow. By combining the observed mass-metallicity relation for both gas and stellar components to constrain the models, we find that only two scenarios are able to reproduce the observations. Either strong metal outflow or a steep initial mass function (IMF) slope at early epochs of galaxy evolution is needed. Based on these two scenarios, for the first time we successfully reproduce the observed MZRgas and MZRstar simultaneously, together with other independent observational constraints in the local Universe. Our model also naturally reproduces the flattening of the MZRgas at the high-mass end leaving the MZRstar intact, as seen in observational data.

  18. INSIGHTS ON THE STELLAR MASS-METALLICITY RELATION FROM THE CALIFA SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    González Delgado, R. M.; García-Benito, R.; Pérez, E.; Cortijo-Ferrero, C.; López Fernández, R.; Sánchez, S. F. [Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía s/n, E-18008 Granada (Spain); Cid Fernandes, R.; De Amorim, A. L.; Lacerda, E. A. D.; Vale Asari, N. [Departamento de Física, Universidade Federal de Santa Catarina, P.O. Box 476, 88040-900 Florianópolis, SC (Brazil); Alves, J. [University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna (Austria); Bland-Hawthorn, J. [Sydney Institute for Astronomy, The University of Sydney, NSW 2006 (Australia); Galbany, L. [Millennium Institute of Astrophysics and Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Gallazzi, A. [INAF—Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze (Italy); Husemann, B. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching b. München (Germany); Bekeraite, S. [Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany); Jungwiert, B. [Astronomical Institute of the Academy of Sciences of the Czech Republic, v.v.i., Bocni II 1401, 14131 Prague (Czech Republic); López-Sánchez, A. R. [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); De Lorenzo-Cáceres, A. [School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS (United Kingdom); Marino, R. A. [CEI Campus Moncloa, UCM-UPM, Departamento de Astrofísica y CC. de la Atmósfera, Facultad de CC. Físicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain); Collaboration: CALIFA collaboration920; and others

    2014-08-10

    We use spatially and temporally resolved maps of stellar population properties of 300 galaxies from the CALIFA integral field survey to investigate how the stellar metallicity (Z {sub *}) relates to the total stellar mass (M {sub *}) and the local mass surface density (μ{sub *}) in both spheroidal- and disk-dominated galaxies. The galaxies are shown to follow a clear stellar mass-metallicity relation (MZR) over the whole 10{sup 9}-10{sup 12} M {sub ☉} range. This relation is steeper than the one derived from nebular abundances, which is similar to the flatter stellar MZR derived when we consider only young stars. We also find a strong relation between the local values of μ{sub *} and Z {sub *} (the μZR), betraying the influence of local factors in determining Z {sub *}. This shows that both local (μ{sub *}-driven) and global (M {sub *}-driven) processes are important in determining metallicity in galaxies. We find that the overall balance between local and global effects varies with the location within a galaxy. In disks, μ{sub *} regulates Z {sub *}, producing a strong μZR whose amplitude is modulated by M {sub *}. In spheroids it is M {sub *} that dominates the physics of star formation and chemical enrichment, with μ{sub *} playing a minor, secondary role. These findings agree with our previous analysis of the star formation histories of CALIFA galaxies, which showed that mean stellar ages are mainly governed by surface density in galaxy disks and by total mass in spheroids.

  19. Hexavalent chromium-induced apoptosis of granulosa cells involves selective sub-cellular translocation of Bcl-2 members, ERK1/2 and p53

    International Nuclear Information System (INIS)

    Banu, Sakhila K.; Stanley, Jone A.; Lee, JeHoon; Stephen, Sam D.; Arosh, Joe A.; Hoyer, Patricia B.; Burghardt, Robert C.

    2011-01-01

    Hexavalent chromium (CrVI) has been widely used in industries throughout the world. Increased usage of CrVI and atmospheric emission of CrVI from catalytic converters of automobiles, and its improper disposal causes various health hazards including female infertility. Recently we have reported that lactational exposure to CrVI induced a delay/arrest in follicular development at the secondary follicular stage. In order to investigate the underlying mechanism, primary cultures of rat granulosa cells were treated with 10 μM potassium dichromate (CrVI) for 12 and 24 h, with or without vitamin C pre-treatment for 24 h. The effects of CrVI on intrinsic apoptotic pathway(s) were investigated. Our data indicated that CrVI: (i) induced DNA fragmentation and increased apoptosis, (ii) increased cytochrome c release from the mitochondria to cytosol, (iii) downregulated anti-apoptotic Bcl-2, Bcl-XL, HSP70 and HSP90; upregulated pro-apoptotic BAX and BAD, (iv) altered translocation of Bcl-2, Bcl-XL, BAX, BAD, HSP70 and HSP90 to the mitochondria, (v) upregulated p-ERK and p-JNK, and selectively translocated p-ERK to the mitochondria and nucleus, (vi) activated caspase-3 and PARP, and (vii) increased phosphorylation of p53 at ser-6, ser-9, ser-15, ser-20, ser-37, ser-46 and ser-392, increased p53 transcriptional activation, and downregulated MDM-2. Vitamin C pre-treatment mitigated CrVI effects on apoptosis and related pathways. Our study, for the first time provides a clear insight into the effect of CrVI on multiple pathways that lead to apoptosis of granulosa cells which could be mitigated by vitamin C.

  20. Understanding the sub-cellular dynamics of silicon transportation and synthesis in diatoms using population-level data and computational optimization.

    Directory of Open Access Journals (Sweden)

    Narjes Javaheri

    2014-06-01

    Full Text Available Controlled synthesis of silicon is a major challenge in nanotechnology and material science. Diatoms, the unicellular algae, are an inspiring example of silica biosynthesis, producing complex and delicate nano-structures. This happens in several cell compartments, including cytoplasm and silica deposition vesicle (SDV. Considering the low concentration of silicic acid in oceans, cells have developed silicon transporter proteins (SIT. Moreover, cells change the level of active SITs during one cell cycle, likely as a response to the level of external nutrients and internal deposition rates. Despite this topic being of fundamental interest, the intracellular dynamics of nutrients and cell regulation strategies remain poorly understood. One reason is the difficulties in measurements and manipulation of these mechanisms at such small scales, and even when possible, data often contain large errors. Therefore, using computational techniques seems inevitable. We have constructed a mathematical model for silicon dynamics in the diatom Thalassiosira pseudonana in four compartments: external environment, cytoplasm, SDV and deposited silica. The model builds on mass conservation and Michaelis-Menten kinetics as mass transport equations. In order to find the free parameters of the model from sparse, noisy experimental data, an optimization technique (global and local search, together with enzyme related penalty terms, has been applied. We have connected population-level data to individual-cell-level quantities including the effect of early division of non-synchronized cells. Our model is robust, proven by sensitivity and perturbation analysis, and predicts dynamics of intracellular nutrients and enzymes in different compartments. The model produces different uptake regimes, previously recognized as surge, externally-controlled and internally-controlled uptakes. Finally, we imposed a flux of SITs to the model and compared it with previous classical kinetics

  1. Fate of airborne metal pollution in soils as related to agricultural management. 1. Zn and Pb distributions in soil profiles

    NARCIS (Netherlands)

    Fernandez, C.; Labanowski, J.; Cambier, P.; Jongmans, A.G.; Oort, van F.

    2007-01-01

    The fate of airborne metal pollutants in soils is still relatively unknown. We studied the incorporation of such airborne metal pollution in two soils under long-term permanent pasture (PP) and conventional arable land (CA). Both soils were located at an almost equal distance from a former zinc

  2. Treatment of cuff-related tracheal stenosis with a fully covered retrievable expandable metallic stent

    International Nuclear Information System (INIS)

    Chen, G.; Wang, Z.; Liang, X.; Wang, Y.; Wang, Y.; Wang, Z.; Xian, J.

    2013-01-01

    Aim: To investigate the clinical effectiveness, complications, and optimal duration of use of covered retrievable expandable metallic stents in the management of cuff-related tracheal stenosis. Materials and methods: Twenty-one patients with cuff-related tracheal stenosis, Meyer–Cotton grade II (29%) and III (71%), who underwent fluoroscopically guided placement of covered retrievable expandable metallic stents were studied. Sixty-four-section computed tomography (CT) and bronchovideoscopy were performed prior to stent insertion, 1 month after stent insertion, in the case of stent-related complications, and after stent removal. Clinical manifestations, Hugh–Jones classification, and forced expiratory volume in 1 s (FEV1) were used to evaluate respiratory function before and after stent insertion and removal. The diameter of the stricture and FEV1 changes before insertion and after removal were analysed using the paired samples t-test. A p-value of ≤0.05 was considered statistically significant. Results: Twenty-one patients had 27 covered retrievable expandable metallic stents placed. Stents were electively removed from 20 patients. The median duration of stent placement was 5 months (range 4–12 months). One stent was not removed due to mucopolysaccharidosis type II (MPS II or Hunter syndrome) with tracheomalacia. After stent removal, airway dimensions increased and airway occlusion was symptomatically relieved in all patients. CT and bronchovideoscopy showed patent lumens with increased dimensions. Stent-related complications occurred in 19 (91%) patients, including granulation tissue formation (n = 18, 86%), stent migration and stent expectoration (n = 2, 10%), mucus plugging (n = 1, 5%), and halitosis (n = 6, 29%). Some patients experienced multiple complications, which were all managed effectively while the stent was still in place. There was a statistically significant difference in the diameter of the stricture and FEV1 between the time of stent

  3. Treatment of cuff-related tracheal stenosis with a fully covered retrievable expandable metallic stent.

    Science.gov (United States)

    Chen, G; Wang, Z; Liang, X; Wang, Y; Wang, Y; Wang, Z; Xian, J

    2013-04-01

    To investigate the clinical effectiveness, complications, and optimal duration of use of covered retrievable expandable metallic stents in the management of cuff-related tracheal stenosis. Twenty-one patients with cuff-related tracheal stenosis, Meyer-Cotton grade II (29%) and III (71%), who underwent fluoroscopically guided placement of covered retrievable expandable metallic stents were studied. Sixty-four-section computed tomography (CT) and bronchovideoscopy were performed prior to stent insertion, 1 month after stent insertion, in the case of stent-related complications, and after stent removal. Clinical manifestations, Hugh-Jones classification, and forced expiratory volume in 1 s (FEV1) were used to evaluate respiratory function before and after stent insertion and removal. The diameter of the stricture and FEV1 changes before insertion and after removal were analysed using the paired samples t-test. A p-value of ≤0.05 was considered statistically significant. Twenty-one patients had 27 covered retrievable expandable metallic stents placed. Stents were electively removed from 20 patients. The median duration of stent placement was 5 months (range 4-12 months). One stent was not removed due to mucopolysaccharidosis type II (MPS II or Hunter syndrome) with tracheomalacia. After stent removal, airway dimensions increased and airway occlusion was symptomatically relieved in all patients. CT and bronchovideoscopy showed patent lumens with increased dimensions. Stent-related complications occurred in 19 (91%) patients, including granulation tissue formation (n = 18, 86%), stent migration and stent expectoration (n = 2, 10%), mucus plugging (n = 1, 5%), and halitosis (n = 6, 29%). Some patients experienced multiple complications, which were all managed effectively while the stent was still in place. There was a statistically significant difference in the diameter of the stricture and FEV1 between the time of stent insertion and removal. An improvement in

  4. Biased resistor network model for electromigration failure and related phenomena in metallic lines

    Science.gov (United States)

    Pennetta, C.; Alfinito, E.; Reggiani, L.; Fantini, F.; Demunari, I.; Scorzoni, A.

    2004-11-01

    Electromigration phenomena in metallic lines are studied by using a biased resistor network model. The void formation induced by the electron wind is simulated by a stochastic process of resistor breaking, while the growth of mechanical stress inside the line is described by an antagonist process of recovery of the broken resistors. The model accounts for the existence of temperature gradients due to current crowding and Joule heating. Alloying effects are also accounted for. Monte Carlo simulations allow the study within a unified theoretical framework of a variety of relevant features related to the electromigration. The predictions of the model are in excellent agreement with the experiments and in particular with the degradation towards electrical breakdown of stressed Al-Cu thin metallic lines. Detailed investigations refer to the damage pattern, the distribution of the times to failure (TTFs), the generalized Black’s law, the time evolution of the resistance, including the early-stage change due to alloying effects and the electromigration saturation appearing at low current densities or for short line lengths. The dependence of the TTFs on the length and width of the metallic line is also well reproduced. Finally, the model successfully describes the resistance noise properties under steady state conditions.

  5. Environmental hazards related to Miscanthus x giganteus cultivation on heavy metal contaminated soil

    Directory of Open Access Journals (Sweden)

    Pogrzeba M.

    2013-04-01

    Full Text Available According to recent estimates reaching the target of a 20% share of renewable energy sources (RES in the final energy balance in Poland by 2020 will result in the demand for more than 8 million tons of biomass, which, in turn, will entail the necessity of creating large-scale energy crop plantations. According to EU assumptions the most effective way to produce biomass for energy purposes is cultivation of energy crops in agricultural areas. It is particularly vital for Poland, because these areas constitute a relatively large part of the country (59%, 76% of them being used as farmlands. In Silesia, the most industrialized region of the country, 5-10% of agricultural soils are contaminated with cadmium, lead and zinc. The main objective of the presented study was to estimate the accumulation of heavy metals in the tissues of Miscanthus x giganteus grown on contaminated soils and calculate concentrations of Pb, Cd and Zn in crops. It was shown that the large intake of heavy metals by that species could cause high emissions of pollutants into the atmosphere during its improper combustion. As a side effect, winter harvesting led to the loss of even 30% of biomass. Plant residues (leaves can be the source of pollution after decomposing and releasing metals back into the soil. Moreover, miscanthus leaves can be transferred by wind to the surrounding areas. It is very likely that ash coming from the combustion of contaminated biomass cannot be used as a fertilizer.

  6. Data-driven modeling of background and mine-related acidity and metals in river basins

    International Nuclear Information System (INIS)

    Friedel, Michael J.

    2014-01-01

    A novel application of self-organizing map (SOM) and multivariate statistical techniques is used to model the nonlinear interaction among basin mineral-resources, mining activity, and surface-water quality. First, the SOM is trained using sparse measurements from 228 sample sites in the Animas River Basin, Colorado. The model performance is validated by comparing stochastic predictions of basin-alteration assemblages and mining activity at 104 independent sites. The SOM correctly predicts (>98%) the predominant type of basin hydrothermal alteration and presence (or absence) of mining activity. Second, application of the Davies–Bouldin criteria to k-means clustering of SOM neurons identified ten unique environmental groups. Median statistics of these groups define a nonlinear water-quality response along the spatiotemporal hydrothermal alteration-mining gradient. These results reveal that it is possible to differentiate among the continuum between inputs of background and mine-related acidity and metals, and it provides a basis for future research and empirical model development. The trained self-organizing map is used to determine upstream hydrothermal alteration (AS – acid sulfate; PROP – propylitic, PROP-V – propylitic veins, QSP – quartz-sericite-pyrite, WSP – weak-sericite-pyrite; Mining activity: MINES) from water-quality measurements in the Animas river basin, Colorado, USA. The white hexagons are sized proportional to the number of water-quality samples associated with that SOM neuron. Highlights: • We model surface-water quality response using a self-organizing map and multivariate statistics. • Applying Davies–Bouldin criteria to k-means clusters defines ten environmental response groups. • The approach differentiates between background and mine-related acidity and metals. -- These results reveal that it is possible to differentiate among the continuum between inputs of background and mine-related acidity and metals

  7. Leukemia-related mortality in towns lying in the vicinity of metal production and processing installations.

    Science.gov (United States)

    García-Pérez, Javier; López-Cima, María Felicitas; Boldo, Elena; Fernández-Navarro, Pablo; Aragonés, Nuria; Pollán, Marina; Pérez-Gómez, Beatriz; López-Abente, Gonzalo

    2010-10-01

    Releases to the environment of toxic substances stemming from industrial metal production and processing installations can pose a health problem to populations in their vicinity. To investigate whether there might be excess leukemia-related mortality in populations residing in towns in the vicinity of Spanish metal industries included in the European Pollutant Emission Register. Ecologic study designed to examine mortality due to leukemia at a municipal level, during the period 1994-2003. Population exposure to pollution was estimated on the basis of distance from town of residence to pollution source. Using Poisson regression models, we analyzed: risk of dying from leukemia in a 5-kilometer zone around installations which had become operational prior to 1990; effect of pollution discharge route and type of industrial activity; and risk gradient within a 50-kilometer radius of such installations. Excess mortality (relative risk, 95% confidence interval) was detected in the vicinity of pre-1990 installations (1.07, 1.02-1.13 in men; 1.05, 1.00-1.11 in women), with this being more elevated in the case of installations that released pollution to air versus water. On stratifying by type of industrial activity, statistically significant associations were also observed among women residing in the vicinity of galvanizing installations (1.58, 1.09-2.29) and surface-treatment installations using an electrolytic or chemical process (1.34, 1.10-1.62), which released pollution to air. There was an effect whereby risk increased with proximity to certain installations. The results suggest an association between risk of dying due to leukemia and proximity to Spanish metal industries. Copyright 2010 Elsevier Ltd. All rights reserved.

  8. FURTHER DEFINITION OF THE MASS-METALLICITY RELATION IN GLOBULAR CLUSTER SYSTEMS AROUND BRIGHTEST CLUSTER GALAXIES

    International Nuclear Information System (INIS)

    Cockcroft, Robert; Harris, William E.; Wehner, Elizabeth M. H.; Whitmore, Bradley C.; Rothberg, Barry

    2009-01-01

    We combine the globular cluster (GC) data for 15 brightest cluster galaxies and use this material to trace the mass-metallicity relations (MMRs) in their globular cluster systems (GCSs). This work extends previous studies which correlate the properties of the MMR with those of the host galaxy. Our combined data sets show a mean trend for the metal-poor subpopulation that corresponds to a scaling of heavy-element abundance with cluster mass Z ∼ M 0.30±0.05 . No trend is seen for the metal-rich subpopulation which has a scaling relation that is consistent with zero. We also find that the scaling exponent is independent of the GCS specific frequency and host galaxy luminosity, except perhaps for dwarf galaxies. We present new photometry in (g',i') obtained with Gemini/GMOS for the GC populations around the southern giant ellipticals NGC 5193 and IC 4329. Both galaxies have rich cluster populations which show up as normal, bimodal sequences in the color-magnitude diagram. We test the observed MMRs and argue that they are statistically real, and not an artifact caused by the method we used. We also argue against asymmetric contamination causing the observed MMR as our mean results are no different from other contamination-free studies. Finally, we compare our method to the standard bimodal fitting method (KMM or RMIX) and find our results are consistent. Interpretation of these results is consistent with recent models for GC formation in which the MMR is determined by GC self-enrichment during their brief formation period.

  9. Multiaxial Cycle Deformation and Low-Cycle Fatigue Behavior of Mild Carbon Steel and Related Welded-Metal Specimen

    Directory of Open Access Journals (Sweden)

    Weilian Qu

    2017-01-01

    Full Text Available The low-cycle fatigue experiments of mild carbon Q235B steel and its related welded-metal specimens are performed under uniaxial, in-phase, and 90° out-of-phase loading conditions. Significant additional cyclic hardening for 90° out-of-phase loading conditions is observed for both base metal and its related weldment. Besides, welding process produces extra additional hardening under the same loading conditions compared with the base metal. Multiaxial low-cycle fatigue strength under 90° out-of-phase loading conditions is significantly reduced for both base-metal and welded-metal specimens. The weldment has lower fatigue life than the base metal under the given loading conditions, and the fatigue life reduction of weldment increases with the increasing strain amplitude. The KBM, FS, and MKBM critical plane parameters are evaluated for the fatigue data obtained. The FS and MKBM parameters are found to show better correlation with fatigue lives for both base-metal and welded-metal specimens.

  10. Traffic Related Aerosol Exposure And Their Risk Assessment Of Associated Metals In Delhi, India

    Directory of Open Access Journals (Sweden)

    Rajesh Kushwaha

    2013-12-01

    Full Text Available A pilot study was carried out in New Delhi, India, to assess the level of traffic related aerosol exposure, individually and associated metals. These investigations also try to formulate their risk assessment using different modes of transport on a typical journey to work route and compared Bus, Auto-rickshaws and Bike (Two Wheelers during the journey. The inhalable particulate matter monitored in winter period and also evaluated the potential health risk due to inhalation in the study. The exposure of Particulate matter was observed maximum in the Bike (502 ± 176.38 μgm-3 and minimum in the Auto-rickshaw (208.15 ± 61.38 μgm-3. In case of human exposure to metals (viz. Cu, Cd, Mn, Pb, Ni, Co, Cr, Fe, Zn, it was mostly exposed by Fe, Zn and Co and least exposed by Cd, Cr and Pb. Human health risk was estimated based on exposure and dosage response. The assessment of particulate-bound elements was calculated by assuming exposure of 6 h. The findings indicated that the exposure to particulate bound elements have relatively more adverse health effects. International Journal of Environment, Volume-2, Issue-1, Sep-Nov 2013, Pages 26-36 DOI: http://dx.doi.org/10.3126/ije.v2i1.9205

  11. Differences in metal sequestration between zebra mussels from clean and polluted field locations.

    Science.gov (United States)

    Voets, Judith; Redeker, Erik Steen; Blust, Ronny; Bervoets, Lieven

    2009-06-04

    Organisms are able to detoxify accumulated metals by, e.g. binding them to metallothionein (MT) and/or sequestering them in metal-rich granules (MRG). The different factors involved in determining the capacity or efficiency with which metals are detoxified are not yet known. In this work we studied how the sub-cellular distribution pattern of cadmium, copper and zinc in whole tissue of zebra mussels from clean and polluted surface waters is influenced by the total accumulated metal concentration and by its physiological condition. Additionally we measured the metallothionein concentration in the mussel tissue. Metal concentration increased gradually in the metal-sensitive and detoxified sub-cellular fractions with increasing whole tissue concentrations. However, metal concentrations in the sensitive fractions did not increase to the same extent as metal concentrations in whole tissues. In more polluted mussels the contribution of MRG and MT became more important. Nevertheless, metal detoxification was not sufficient to prevent metal binding to heat-sensitive low molecular weight proteins (HDP fraction). Finally we found an indication that metal detoxification was influenced by the condition of the zebra mussels. MT content could be explained for up to 83% by variations in Zn concentration and physiological condition of the mussels.

  12. Differences in metal sequestration between zebra mussels from clean and polluted field locations

    International Nuclear Information System (INIS)

    Voets, Judith; Redeker, Erik Steen; Blust, Ronny; Bervoets, Lieven

    2009-01-01

    Organisms are able to detoxify accumulated metals by, e.g. binding them to metallothionein (MT) and/or sequestering them in metal-rich granules (MRG). The different factors involved in determining the capacity or efficiency with which metals are detoxified are not yet known. In this work we studied how the sub-cellular distribution pattern of cadmium, copper and zinc in whole tissue of zebra mussels from clean and polluted surface waters is influenced by the total accumulated metal concentration and by its physiological condition. Additionally we measured the metallothionein concentration in the mussel tissue. Metal concentration increased gradually in the metal-sensitive and detoxified sub-cellular fractions with increasing whole tissue concentrations. However, metal concentrations in the sensitive fractions did not increase to the same extent as metal concentrations in whole tissues. In more polluted mussels the contribution of MRG and MT became more important. Nevertheless, metal detoxification was not sufficient to prevent metal binding to heat-sensitive low molecular weight proteins (HDP fraction). Finally we found an indication that metal detoxification was influenced by the condition of the zebra mussels. MT content could be explained for up to 83% by variations in Zn concentration and physiological condition of the mussels.

  13. Differences in metal sequestration between zebra mussels from clean and polluted field locations

    Energy Technology Data Exchange (ETDEWEB)

    Voets, Judith [Laboratory for Ecophysiology, Biochemistry and Toxicology, Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Redeker, Erik Steen [Laboratory for Ecophysiology, Biochemistry and Toxicology, Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Institute for Materials Research, Chemistry Division, Hasselt University, Agoralaan Building D G1-36, B 3590 Diepenbeek (Belgium); Blust, Ronny [Laboratory for Ecophysiology, Biochemistry and Toxicology, Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Bervoets, Lieven, E-mail: Lieven.bervoets@ua.ac.be [Laboratory for Ecophysiology, Biochemistry and Toxicology, Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium)

    2009-06-04

    Organisms are able to detoxify accumulated metals by, e.g. binding them to metallothionein (MT) and/or sequestering them in metal-rich granules (MRG). The different factors involved in determining the capacity or efficiency with which metals are detoxified are not yet known. In this work we studied how the sub-cellular distribution pattern of cadmium, copper and zinc in whole tissue of zebra mussels from clean and polluted surface waters is influenced by the total accumulated metal concentration and by its physiological condition. Additionally we measured the metallothionein concentration in the mussel tissue. Metal concentration increased gradually in the metal-sensitive and detoxified sub-cellular fractions with increasing whole tissue concentrations. However, metal concentrations in the sensitive fractions did not increase to the same extent as metal concentrations in whole tissues. In more polluted mussels the contribution of MRG and MT became more important. Nevertheless, metal detoxification was not sufficient to prevent metal binding to heat-sensitive low molecular weight proteins (HDP fraction). Finally we found an indication that metal detoxification was influenced by the condition of the zebra mussels. MT content could be explained for up to 83% by variations in Zn concentration and physiological condition of the mussels.

  14. The mass-metallicity and fundamental metallicity relations at z > 2 using very large telescope and Subaru near-infrared spectroscopy of zCOSMOS galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Maier, C.; Ziegler, B. L. [Department of Astrophysics, University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna (Austria); Lilly, S. J.; Peng, Y. [Institute of Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Contini, T. [Institut de Recherche en Astrophysique et Planétologie, CNRS, 14 avenue Édouard Belin, F-31400 Toulouse (France); Pérez Montero, E. [Instituto de Astrofísica de Andalucia, CSIC, Apartado de Correos 3004, E-18080 Granada (Spain); Balestra, I., E-mail: christian.maier@univie.ac.at [Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, Giessenbachstrasse, D-85741 Garching b. München (Germany)

    2014-09-01

    In the local universe, there is good evidence that, at a given stellar mass M, the gas-phase metallicity Z is anti-correlated with the star formation rate (SFR) of the galaxies. It has also been claimed that the resulting Z(M, SFR) relation is invariant with redshift—the so-called 'fundamental metallicity relation' (FMR). Given a number of difficulties in determining metallicities, especially at higher redshifts, the form of the Z(M, SFR) relation and whether it is really independent of redshift is still very controversial. To explore this issue at z > 2, we used VLT-SINFONI and Subaru-MOIRCS near-infrared spectroscopy of 20 zCOSMOS-deep galaxies at 2.1 < z < 2.5 to measure the strengths of up to five emission lines: [O II] λ3727, Hβ, [O III] λ5007, Hα, and [N II] λ6584. This near-infrared spectroscopy enables us to derive O/H metallicities, and also SFRs from extinction corrected Hα measurements. We find that the mass-metallicity relation (MZR) of these star-forming galaxies at z ≈ 2.3 is lower than the local Sloan Digital Sky Survey (SDSS) MZR by a factor of three to five, a larger change than found by Erb et al. using [N II]/Hα-based metallicities from stacked spectra. We discuss how the different selections of the samples and metallicity calibrations used may be responsible for this discrepancy. The galaxies show direct evidence that the SFR is still a second parameter in the MZR at these redshifts. However, determining whether the Z(M, SFR) relation is invariant with epoch depends on the choice of extrapolation used from local samples, because z > 2 galaxies of a given mass have much higher SFRs than the local SDSS galaxies. We find that the zCOSMOS galaxies are consistent with a non-evolving FMR if we use the physically motivated formulation of the Z(M, SFR) relation from Lilly et al., but not if we use the empirical formulation of Mannucci et al.

  15. The effects of pH and concentration on heavy metal speciation and mobility, and its relation to heavy metal hyperaccumulation and distribution in selected native Australian flora

    International Nuclear Information System (INIS)

    Menon, D.D.; McPhail, D.C.; Hallam, N.

    2000-01-01

    Full text: The purpose of this research is to establish a clearer understanding of the relations that exist between heavy metal activity, speciation, bioavailability and their uptake and spatial distribution into plants. A combination of experimental modeling and pot trials using toxic heavy metals (cadmium, lead, mercury, copper, chromium and zinc) will be carried out. In the experiments, selected native Australian flora (Eucalyptus, Acacia, Atriplex) adapted to adverse environmental conditions will be used. Varying external factors such as pH, and metal concentration altered the composition of heavy metal speciation in the soil solution. Mathematical and geochemical (PHREEQC) models were used to vary these factors and emulate the conditions under which experimentation will be taking place. These variations help determine the possible heavy metal speciation that would occur in both soil and hydroponic based experiments under given conditions. The rhizosphere, soil solution and the plant material will be analysed by Inductively Coupled Plasma Mass Spectroscopy (ICPMS). Proton Ion X-ray Emission (PIXE) and Secondary Ion Mass spectrometry will help ascertain the distribution, concentration of heavy metal taken up into plant tissues. Information derived from these data will be used to determine and understand how varying such environmental conditions and hence heavy metal speciation affect their bioavailability in the medium, and how their acceptance, accumulation and storage within the selected flora. Preliminary experimentation showed that, for lead and cadmium, the variation in soil solution pH affected the quantity of heavy metal accumulated into selected native Australian flora. ICP-MS analysis of plants subjected to a known soil solution spiked with 200 μmol of lead and cadmium showed that the quantities of lead and cadmium accumulated into plant sections (roots, stems and leaves) varied in the selected woody species. A. heteroclita, A. saligna, and A

  16. Hemodialysis shunts-related subclavian vein stenosis : treatment with self-expandable metallic stent

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Gyee; Lee, Young Chul; Shin, Sang Soo; Kim, Yun Hyeon; Kim, Jae Kyu; Kang, Heoung Keun; Jeong, Sang Young; Choi, Su Jin Na [Chonnam Univ. College of Medicine, Kwangju (Korea, Republic of)

    1999-04-01

    To evaluate the usefulness of placement of self-expandable stents in hemodialytic shunt-related subclavian vein stenosis. Self-expandable metallic stent was placed in nine patients with hemodialytic shunt-related subclavian vein stenosis. In seven cases, angioplasty was attempted before stent placement; in five, stents were placed immediately after failed angioplasty; and in two, due to restenosis after angioplasty. Procedures involved a 10mm diameter, 7-10cm length Wallstent in eight cases, and a 10mm diameter, 8cm length Hanaro stent in one. In all cases, clinical follow-up, which included physical examination and the measurement of venous resistance pressure during hemodialysis, was performed. The follow-up period was between 5 months and 1 year 7 months. Repeated intervention was performed if restenosis was detected. The stenotic sites were in eight cases the site of a previous subclavian venous line, and in one, the site of anatomic narrowing at the thoracic inlet of the subclavian vein. The technical success rate was 100%;a resulting complication was stent migration into the right atrium in one case in which a Hanaro stent had been used; this was removed by snaring. During follow-up of the eight patients in whon stent placement was successful, restenosis developed in three cases. This occurred during the 7th, 8th, and 15th month, respectively. Two such cases were treated by balloon dilatation. In hemodialytic shunt-related subclavian vein stenosis, treatment involving the use of a self-expandable metallic stent is useful, especially for treating a lesion which has not responded to angioplasty with a high patency rate.

  17. Hemodialysis shunts-related subclavian vein stenosis : treatment with self-expandable metallic stent

    International Nuclear Information System (INIS)

    Kim, Sang Gyee; Lee, Young Chul; Shin, Sang Soo; Kim, Yun Hyeon; Kim, Jae Kyu; Kang, Heoung Keun; Jeong, Sang Young; Choi, Su Jin Na

    1999-01-01

    To evaluate the usefulness of placement of self-expandable stents in hemodialytic shunt-related subclavian vein stenosis. Self-expandable metallic stent was placed in nine patients with hemodialytic shunt-related subclavian vein stenosis. In seven cases, angioplasty was attempted before stent placement; in five, stents were placed immediately after failed angioplasty; and in two, due to restenosis after angioplasty. Procedures involved a 10mm diameter, 7-10cm length Wallstent in eight cases, and a 10mm diameter, 8cm length Hanaro stent in one. In all cases, clinical follow-up, which included physical examination and the measurement of venous resistance pressure during hemodialysis, was performed. The follow-up period was between 5 months and 1 year 7 months. Repeated intervention was performed if restenosis was detected. The stenotic sites were in eight cases the site of a previous subclavian venous line, and in one, the site of anatomic narrowing at the thoracic inlet of the subclavian vein. The technical success rate was 100%;a resulting complication was stent migration into the right atrium in one case in which a Hanaro stent had been used; this was removed by snaring. During follow-up of the eight patients in whon stent placement was successful, restenosis developed in three cases. This occurred during the 7th, 8th, and 15th month, respectively. Two such cases were treated by balloon dilatation. In hemodialytic shunt-related subclavian vein stenosis, treatment involving the use of a self-expandable metallic stent is useful, especially for treating a lesion which has not responded to angioplasty with a high patency rate

  18. Indoor metallic pollution related to mining activity in the Bolivian Altiplano

    International Nuclear Information System (INIS)

    Fonturbel, Francisco E.; Barbieri, Enio; Herbas, Cristian; Barbieri, Flavia L.; Gardon, Jacques

    2011-01-01

    The environmental pollution associated with mining and metallurgical activities reaches its greatest extent in several Andean cities and villages. Many locations in this area have accumulated through centuries a large amount of mining wastes, often disregarding the magnitude of this situation. However, in these naturally mineralized regions, there is little information available stating the exact role of mining and metallurgical industries in urban pollution. In this study, we demonstrated that the various metallic elements present in indoor dust (As, Cd, Cu, Pb, Sb, Sn, Zn) had a common origin and this contamination was increased by the proximity to the mines. Lead dust concentration was found at concerning levels for public health. In addition, wrong behaviors such as carrying mining workwear home contributed to this indoor dust pollution. Consequently, the constant exposure of the population could represent a potential health hazard for vulnerable groups, especially children. - Highlights: → We measured polymetallic pollution in household indoor dust from a mining town. → Toxic elements (Pb, As, Cd, Sb) in dust are correlated, suggesting a common origin. → The most polluted houses are within a 1 km radius around the mining center. → Carrying mining workwear home increases indoor pollution. → Lead concentrations in dust represent a serious concern for Public Health (600 μg/g). - In a typical Andean mining city, the urban indoor pollution with toxic metallic elements is directly related to the closeness of the mining activities.

  19. Indoor metallic pollution related to mining activity in the Bolivian Altiplano

    Energy Technology Data Exchange (ETDEWEB)

    Fonturbel, Francisco E., E-mail: fonturbel@ug.uchile.cl [Departamento de Ciencias Ecologicas, Facultad de Ciencias, Universidad de Chile, Santiago (Chile); Barbieri, Enio [IRD-HSM (Institut de Recherche pour le Developpement), La Paz (Bolivia, Plurinational State of); Herbas, Cristian [Universidad Mayor de San Andres, IGEMA Institute (Instituto de Investigaciones Geologicas y del Medio Ambiente), La Paz (Bolivia, Plurinational State of); Barbieri, Flavia L.; Gardon, Jacques [IRD-HSM (Institut de Recherche pour le Developpement), La Paz (Bolivia, Plurinational State of); Universidad Mayor de San Andres, SELADIS Institute (Instituto de Servicios de Laboratorio para el Diagnostico e Investigacion en Salud), La Paz (Bolivia, Plurinational State of)

    2011-10-15

    The environmental pollution associated with mining and metallurgical activities reaches its greatest extent in several Andean cities and villages. Many locations in this area have accumulated through centuries a large amount of mining wastes, often disregarding the magnitude of this situation. However, in these naturally mineralized regions, there is little information available stating the exact role of mining and metallurgical industries in urban pollution. In this study, we demonstrated that the various metallic elements present in indoor dust (As, Cd, Cu, Pb, Sb, Sn, Zn) had a common origin and this contamination was increased by the proximity to the mines. Lead dust concentration was found at concerning levels for public health. In addition, wrong behaviors such as carrying mining workwear home contributed to this indoor dust pollution. Consequently, the constant exposure of the population could represent a potential health hazard for vulnerable groups, especially children. - Highlights: > We measured polymetallic pollution in household indoor dust from a mining town. > Toxic elements (Pb, As, Cd, Sb) in dust are correlated, suggesting a common origin. > The most polluted houses are within a 1 km radius around the mining center. > Carrying mining workwear home increases indoor pollution. > Lead concentrations in dust represent a serious concern for Public Health (600 {mu}g/g). - In a typical Andean mining city, the urban indoor pollution with toxic metallic elements is directly related to the closeness of the mining activities.

  20. Oxidative damage to collagen and related substrates by metal ion/hydrogen peroxide systems

    DEFF Research Database (Denmark)

    Hawkins, C L; Davies, Michael Jonathan

    1997-01-01

    . In this study electron paramagnetic resonance spectroscopy with spin trapping has been used to identify radicals formed on collagen and related materials by metal ion-H2O2 mixtures. Attack of the hydroxyl radical, from a Fe(II)-H2O2 redox couple, on collagen peptides gave signals from both side chain (.CHR...... are similar to those from the alpha-carbon site of peptides and the side-chain of lysine. Enzymatic digestion of the large, protein-derived, species releases similar low-molecular-weight adducts. The metal ion employed has a dramatic effect on the species observed. With Cu(I)-H2O2 or Cu(II)-H2O2 instead of Fe(II)-H......2O2, evidence has been obtained for: i) altered sites of attack and fragmentation, ii) C-terminal decarboxylation, and iii) hydrogen abstraction at N-terminal alpha-carbon sites. This altered behaviour is believed to be due to the binding of copper ions to some substrates and hence site...

  1. Investigation Effect of Biorhythm on Work-Related Accidents in The Metal Industry (A Short Report

    Directory of Open Access Journals (Sweden)

    Ehsanollah Habibi

    2016-07-01

    Full Text Available Biorhythm is one of the newest subjects in the field of cognition of mental ergonomics which can be very effective in reduction of work-related accidents or mistakes with no apparent reason. With evaluating Biorhythm individuals can intervention action to reduce job accidents carried out. Thus, the aim of this study was to determine the relationship Biorhythm and work-related accidents in the metal industry. This research is a cross-sectional and analytical-descriptive in the metal industrial Isfahan city of 120 work-related accidents during 2015. The required information was collected from available documents in HSE unit of the company biorhythm charts were drawn based on a date of accidents and participants birthdays, using natural Biorhythm Software V3.02 Conduct. Finally، the data were analyzed using spss version 20 and descriptive statistics.This study showed that the frequency of accidents in critical days and negative section of physical cycle was more than expected. Also the frequency of accidents in critical days and negative section of emotional and intellectual cycles was less than expected. Most type of injury, including cuts to 35.8 percent and the lowest type of injury was torsion with 5 percent. Most limb injury, hands and fingers with 51.7 percent and the lowest limb injury were back at 2.5 percent. Accidents outbreak in physical cycles was 38.3 percent. These 120 accidents in additionally were causing 120 loss of working days in effect accident. Most percent of loss of working days were for 20 to 30 days with of 39.2 percent. Most percent of loss of working days were for 20 to 30 days with of 39.2 percent. Due to the physical nature of the work activities in the metal industry can be stated that the study showed that in physical work activities, frequency of accidents in critical days and negative section of physical cycle in which the person is not physically ready to do the job was more than expected. Therefore, by training

  2. Do galaxy global relationships emerge from local ones? The SDSS IV MaNGA surface mass density-metallicity relation

    Science.gov (United States)

    Barrera-Ballesteros, Jorge K.; Heckman, Timothy M.; Zhu, Guangtun B.; Zakamska, Nadia L.; Sánchez, Sebastian F.; Law, David; Wake, David; Green, Jenny E.; Bizyaev, Dmitry; Oravetz, Daniel; Simmons, Audrey; Malanushenko, Elena; Pan, Kaike; Roman Lopes, Alexandre; Lane, Richard R.

    2016-12-01

    We present the stellar surface mass density versus gas metallicity (Σ*-Z) relation for more than 500 000 spatially resolved star-forming resolution elements (spaxels) from a sample of 653 disc galaxies included in the SDSS IV MaNGA survey. We find a tight relation between these local properties, with higher metallicities as the surface density increases. This relation extends over three orders of magnitude in the surface mass density and a factor of 4 in metallicity. We show that this local relationship can simultaneously reproduce two well-known properties of disc galaxies: their global mass-metallicity relationship and their radial metallicity gradients. We also find that the Σ*-Z relation is largely independent of the galaxy's total stellar mass and specific star formation rate (sSFR), except at low stellar mass and high sSFR. These results suggest that in the present-day universe local properties play a key role in determining the gas-phase metallicity in typical disc galaxies.

  3. A hidden variable in shear transformation zone volume versus Poisson's ratio relation in metallic glasses

    Science.gov (United States)

    Kim, S. Y.; Oh, H. S.; Park, E. S.

    2017-10-01

    Herein, we elucidate a hidden variable in a shear transformation zone (STZ) volume (Ω) versus Poisson's ratio (ν) relation and clarify the correlation between STZ characteristics and the plasticity of metallic glasses (MGs). On the basis of cooperative shear model and atomic stress theories, we carefully formulate Ω as a function of molar volume (Vm) and ν. The twofold trend in Ω and ν is attributed to a relatively large variation of Vm as compared to that of ν as well as an inverse relation between Vm and ν. Indeed, the derived equation reveals that the number of atoms in an STZ instead of Ω is a microstructural characteristic which has a close relationship with plasticity since it reflects the preference of atomistic behaviors between cooperative shearing and the generation of volume strain fluctuation under stress. The results would deepen our understanding of the correlation between microscopic behaviors (STZ activation) and macroscopic properties (plasticity) in MGs and enable a quantitative approach in associating various STZ-related macroscopic behaviors with intrinsic properties of MGs.

  4. Structural studies of metal oxides related to High-Tc superconductors

    International Nuclear Information System (INIS)

    Hjorth, M.

    1990-02-01

    The project was started in order to investigate metal oxide structures related in some way to high-T c superconductors, using the crystallographic methods available; and in order to be able to use crystallographic methods in ways that go beyond routine applications in order to contribute to the crystallographic knowledge concerning these oxides. The project goes a step outside the boarders normally defined by using the term ''high-T c superconductors'', thus studying metal oxides from a more general crystallographic viewpoint. The methods used are the expansions of the spherical atom model, and of the thermal probability density function, and combination of X-ray work with high resolution electron microscopy. The use of the expanded diffraction models presents problems such as bad convergence in least squares refinement, physical unreasonable parameters, problems with interpretation of the results and difficulties due to missing or insufficient computer programs. The use of these models is discussed. Dynamical theory is applied when considering electron diffraction results. The theory is presented, focusing on the modifications of the standard theory used for some of the structures considered in the thesis, and in overview on other theoretical topics is given. A presentation is given of the structures which have been considered and of earlier work on related compounds, of the problems and solutions applied to the compound discussed and of the results obtained. The results are discussed. The appendices describe published papers and the work not directly connected to the main topics, e.g. implementation and development of computer programs. (AB) 172 refs

  5. Relations between metals (Zn, Pb, Cd and Cu) and glutathione-dependent detoxifying enzymes in spiders from a heavy metal pollution gradient

    International Nuclear Information System (INIS)

    Wilczek, Grazyna; Babczynska, Agnieszka; Augustyniak, Maria; Migula, Pawel

    2004-01-01

    We studied the relations between glutathione-dependent detoxifying enzymes and heavy metal burdens in the web-building spider Agelena labyrinthica (Agelenidae) and the wolf spider Pardosa lugubris (Lycosidae) from five meadow sites along a heavy metal pollution gradient. We assayed the activity of glutathione-S-transferase (GST) and glutathione peroxidases (GPOX, GSTPx), and glutathione (GSH) levels in both sexes. Except for GSH vs Pb content, we found significant correlations between GPOX and GSTPx activity and metal concentrations in females of A. labyrinthica. The highest activity of these enzymes measured in the web-building spiders was found in the individuals from the most polluted sites. In P. lugubris males significant correlations were found between GST and Pb and Zn concentrations, and between GPOX and GSTPx and the concentration of Cu. GST activity was higher in males collected from less polluted areas. Thus, detoxifying strategies against pollutants seemed to be sex-dependent. Actively hunting spiders had higher metal concentrations, maintaining lower activity of detoxifying enzymes and a lower glutathione level. - Capsule: Glutathione-linked enzyme activity in spiders from polluted areas depends on hunting strategy and sex

  6. Relations between metals (Zn, Pb, Cd and Cu) and glutathione-dependent detoxifying enzymes in spiders from a heavy metal pollution gradient

    Energy Technology Data Exchange (ETDEWEB)

    Wilczek, Grazyna [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland); Babczynska, Agnieszka [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland); Augustyniak, Maria [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland); Migula, Pawel [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland)]. E-mail: migula@us.edu.pl

    2004-12-01

    We studied the relations between glutathione-dependent detoxifying enzymes and heavy metal burdens in the web-building spider Agelena labyrinthica (Agelenidae) and the wolf spider Pardosa lugubris (Lycosidae) from five meadow sites along a heavy metal pollution gradient. We assayed the activity of glutathione-S-transferase (GST) and glutathione peroxidases (GPOX, GSTPx), and glutathione (GSH) levels in both sexes. Except for GSH vs Pb content, we found significant correlations between GPOX and GSTPx activity and metal concentrations in females of A. labyrinthica. The highest activity of these enzymes measured in the web-building spiders was found in the individuals from the most polluted sites. In P. lugubris males significant correlations were found between GST and Pb and Zn concentrations, and between GPOX and GSTPx and the concentration of Cu. GST activity was higher in males collected from less polluted areas. Thus, detoxifying strategies against pollutants seemed to be sex-dependent. Actively hunting spiders had higher metal concentrations, maintaining lower activity of detoxifying enzymes and a lower glutathione level. - Capsule: Glutathione-linked enzyme activity in spiders from polluted areas depends on hunting strategy and sex.

  7. Acute effects of heavy metals on the expression of glutathione-related antioxidant genes in the marine ciliate Euplotes crassus

    International Nuclear Information System (INIS)

    Kim, Se-Hun; Kim, Se-Joo; Lee, Jae-Seong; Lee, Young-Mi

    2014-01-01

    Highlights: • Significant higher increases in the relative ROS and total GSH levels were observed after exposure to heavy metals. • Real-time PCR data showed expression levels of GPx and GR mRNA were sensitively modulated within 8 h of exposure to heavy metals. • E. crassus GPx and GR genes may be involved in cellular defense mechanisms against heavy metal-induced oxidative stress. • E. crassus GPx and GR genes will be useful as potential molecular markers for monitoring heavy metal contamination. - Abstract: Euplotes crassus, a single-celled eukaryote, is directly affected by environmental contaminants. Here, exponentially cultured E. crassus were exposed to cadmium, copper, lead, and zinc and then the reactive oxygen species (ROS) and total glutathione (GSH) levels were measured. Subsequently, the transcriptional modulation of glutathione peroxidase (GPx) and glutathione reductase (GR) were estimated by quantitative RT-PCR. After an 8-h exposure, significantly higher increases in the relative ROS and total GSH levels were observed in exposed group, compared to the controls. Real-time PCR data revealed that the expression levels of GPx and GR mRNA were sensitively modulated within 8 h of exposure to all heavy metals. These findings suggest that these genes may be involved in cellular defense mechanisms by modulating their gene expression against heavy metal-induced oxidative stress. Thus, they may be useful as potential molecular biomarkers to assess sediment environments for contaminants

  8. THE REDSHIFT EVOLUTION OF THE RELATION BETWEEN STELLAR MASS, STAR FORMATION RATE, AND GAS METALLICITY OF GALAXIES

    International Nuclear Information System (INIS)

    Niino, Yuu

    2012-01-01

    We investigate the relation between stellar mass (M * ), star formation rate (SFR), and metallicity (Z) of galaxies, the so-called fundamental metallicity relation, in the galaxy sample of the Sloan Digital Sky Survey Data Release 7. We separate the galaxies into narrow redshift bins and compare the relation at different redshifts and find statistically significant (>99%) evolution. We test various observational effects that might cause seeming Z evolution and find it difficult to explain the evolution of the relation only by the observational effects. In the current sample of low-redshift galaxies, galaxies with different M * and SFR are sampled from different redshifts, and there is degeneracy between M * /SFR and redshift. Hence, it is not straightforward to distinguish a relation between Z and SFR from a relation between Z and redshift. The separation of the intrinsic relation from the redshift evolution effect is a crucial issue in the understanding of the evolution of galaxies.

  9. Relations between variously available fractions of trace metals in the soil and their actual plant-uptake

    International Nuclear Information System (INIS)

    Bujtas, K.; Csillag, J.

    1999-01-01

    In a pot experiment, availabilities of Cd, Cr, Ni, Pb, and Zn added to the soil as metal nitrates or as enrichment of sewage sludge were evaluated by comparing concentrations of their total potentially available, presumably plant-available and directly plant-available forms in the soil. At excessively increasing soil contamination, the plant-available concentrations increased more than the total soil contents, thus the relative availabilities of the metals increased. This was reflected in the amounts taken up by the young maize test plants and in the plant/soil transfer factors. Transfer factors calculated for the 'plant-available' soil metal contents depended less on the contamination level than those based on total soil metal contents. Refs. 8 (author)

  10. On a New Theoretical Framework for RR Lyrae Stars. II. Mid-infrared Period–Luminosity–Metallicity Relations

    Energy Technology Data Exchange (ETDEWEB)

    Neeley, Jillian R.; Marengo, Massimo; Trueba, Nicolas [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Bono, Giuseppe; Braga, Vittorio F.; Magurno, Davide [Department of Physics, Università di Roma Tor Vergara, via della Ricerca Scientifica 1, I-00133 Roma (Italy); Dall’Ora, Massimo; Marconi, Marcella [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiarello 16, I-80131 Napoli (Italy); Tognelli, Emanuele; Moroni, Pier G. Prada [Dipartimento di Fisica, Università di Pisa, Lago Bruno Pontecorvo 3, I-56127, Pisa (Italy); Beaton, Rachael L.; Madore, Barry F.; Seibert, Mark [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Freedman, Wendy L. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Monson, Andrew J. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Scowcroft, Victoria [Department of Physics, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Stetson, Peter B., E-mail: jrneeley@iastate.edu [NRC-Herzberg, Dominion Astrophysical Observatory, 5071 West Saanich Road, Victoria BC V9E 2E7 (Canada)

    2017-06-01

    We present new theoretical period–luminosity–metallicity (PLZ) relations for RR Lyræ stars (RRLs) at Spitzer and WISE wavelengths. The PLZ relations were derived using nonlinear, time-dependent convective hydrodynamical models for a broad range of metal abundances ( Z = 0.0001–0.0198). In deriving the light curves, we tested two sets of atmospheric models and found no significant difference between the resulting mean magnitudes. We also compare our theoretical relations to empirical relations derived from RRLs in both the field and in the globular cluster M4. Our theoretical PLZ relations were combined with multi-wavelength observations to simultaneously fit the distance modulus, μ {sub 0}, and extinction, A {sub V}, of both the individual Galactic RRL and of the cluster M4. The results for the Galactic RRL are consistent with trigonometric parallax measurements from Gaia ’ s first data release. For M4, we find a distance modulus of μ {sub 0} = 11.257 ± 0.035 mag with A {sub V}= 1.45 ± 0.12 mag, which is consistent with measurements from other distance indicators. This analysis has shown that, when considering a sample covering a range of iron abundances, the metallicity spread introduces a dispersion in the PL relation on the order of 0.13 mag. However, if this metallicity component is accounted for in a PLZ relation, the dispersion is reduced to ∼0.02 mag at mid-infrared wavelengths.

  11. Relating Magnetic Parameters to Heavy Metal Concentrations and Environmental Factors at Formosa Mine Superfund Site, Douglas County, OR

    Science.gov (United States)

    Upton, T. L.

    2016-12-01

    Advances in the field of environmental magnetism have led to exciting new applications for this field. Magnetic minerals are ubiquitous in the environment and tend to have an affinity for heavy metals. Hence, it has been demonstrated that magnetic properties are often significantly related to concentrations of heavy metals and other pollutants. As a result, magnetic techniques have been used as proxy for determining hot spots of several types of pollution produced from a diversity of anthropogenic sources. Magnetic measurements are non-destructive and relatively inexpensive compared to geochemical analyses. The utility of environmental magnetic methods varies widely depending on biological, chemical and physical processes that create and transform soils and sediments. Applications in the direction of mapping heavy metals have been studied and shown to be quite useful in countries such as China and India but to date, little research has been done in the US. As such, there is need to expand the scope of research to a wider range of soil types and land uses, especially within the US. This study investigates the application of environmental magnetic techniques to mapping of heavy metal concentrations at the Formosa Mine Superfund Site, an abandoned mine about 25 miles southwest of Roseburg, OR. The soils and sediment at this site are derived from pyrite-rich bedrock which is weak in terms of magnetic susceptibility. Using hotspot analysis, correlation and cluster analyses, interactions between metals and magnetic parameters are investigated in relation to environmental factors such as proximity to seeps and adits. Preliminary results suggest significant correlation of magnetic susceptibility with certain heavy metals, signifying that magnetic methods may be useful in mapping heavy metal hotspots at this site. Further analysis examines the relation of various land use differences in magnetic signatures obtained throughout the Cow Creek watershed.

  12. Bioaccessibility of metal cations in soil is linearly related to its water exchange rate constant.

    Science.gov (United States)

    Laird, Brian D; Peak, Derek; Siciliano, Steven D

    2011-05-01

    Site-specific risk assessments often incorporate the concepts of bioaccessibility (i.e., contaminant fraction released into gastrointestinal fluids) or bioavailability (i.e., contaminant fraction absorbed into systemic circulation) into the calculation of ingestion exposure. We evaluated total and bioaccessible metal concentrations for 19 soil samples under simulated stomach and duodenal conditions using an in vitro gastrointestinal model. We demonstrated that the median bioaccessibility of 23 metals ranged between exchange rates of metal cations (k(H₂O)) indicated that desorption kinetics may influence if not control metal bioaccessibility.

  13. Corrosion of valve metals

    International Nuclear Information System (INIS)

    Draley, J.E.

    1976-01-01

    A general survey related to the corrosion of valve metals or film-forming metals. The way these metals corrode with some general examples is described. Valve metals form relatively perfect oxide films with little breakdown or leakage when anodized

  14. Chemical speciation of heavy metals in sandy soils in relation to availability and mobility

    NARCIS (Netherlands)

    Temminghoff, E.J.M.

    1998-01-01

    The environmental risk of heavy metals which are present in soil at a certain total content is highly dependent on soil properties. Chemical speciation is a comprehensive term for the distribution of heavy metals over all possible chemical forms (species) in soil solution and in the solid

  15. ELECTED PROBLEMS RELATED TO ENVIRONMENTAL HEAVY METALS EXPOSURE AND CHELATION THERAPY

    Directory of Open Access Journals (Sweden)

    Anna Skoczyńska

    2010-09-01

    Full Text Available Background: Exposure to heavy metals leads to functional and metabolic disturbances and many of them are included in pathogenesis of common diseases (arterial hypertension, atherosclerosis, neurodegenerative processes. In this context new therapeutic and prophylactic strategies are necessary. Patients diagnosed with chronic heavy metals intoxication usually require chelation to increase mobilisation of metals from tissues and elimination of them via urine. Acute poisoning with toxic metal may be difficult to diagnosis, especially in case of accidental intoxication or suicidal intention. Patients also require chelation after causative factor is identified. Objectives: To describe some problems connected with toxicity of metals poisoning and to review pharmacologic therapies that could have a role in poisoning with metals. Methods: A review of the literature was carried out and expert opinion expressed. Results/conclusion: Chelation is a common therapy in case of poisoning with toxic metals but it is satisfied only partially. A combined therapy with structurally different chelators or long-term acting chelators could become viable alternatives in the future. A combined therapy with an antioxidant plus chelator may be a good choice in patients chronically poisoned with metals. Exposure to lead should be taken into account during estimation of global cardiovascular risk.

  16. Perspective on Structural Evolution and Relations with Thermophysical Properties of Metallic Liquids.

    Science.gov (United States)

    Wang, Xiao-Dong; Jiang, Jian-Zhong

    2017-11-01

    The relationship between the structural evolution and properties of metallic liquids is a long-standing hot issue in condensed-matter physics and materials science. Here, recent progress is reviewed in several fundamental aspects of metallic liquids, including the methods to study their atomic structures, liquid-liquid transition, physical properties, fragility, and their correlations with local structures, together with potential applications of liquid metals at room temperature. Involved with more experimentally and theoretically advanced techniques, these studies provide more in-depth understanding of the structure-property relationship of metallic liquids and promote the design of new metallic materials with superior properties. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Data-driven modeling of background and mine-related acidity and metals in river basins

    Science.gov (United States)

    Friedel, Michael J

    2013-01-01

    A novel application of self-organizing map (SOM) and multivariate statistical techniques is used to model the nonlinear interaction among basin mineral-resources, mining activity, and surface-water quality. First, the SOM is trained using sparse measurements from 228 sample sites in the Animas River Basin, Colorado. The model performance is validated by comparing stochastic predictions of basin-alteration assemblages and mining activity at 104 independent sites. The SOM correctly predicts (>98%) the predominant type of basin hydrothermal alteration and presence (or absence) of mining activity. Second, application of the Davies–Bouldin criteria to k-means clustering of SOM neurons identified ten unique environmental groups. Median statistics of these groups define a nonlinear water-quality response along the spatiotemporal hydrothermal alteration-mining gradient. These results reveal that it is possible to differentiate among the continuum between inputs of background and mine-related acidity and metals, and it provides a basis for future research and empirical model development.

  18. Stability of biogenic metal(loid) nanomaterials related to the colloidal stabilization theory of chemical nanostructures.

    Science.gov (United States)

    Piacenza, Elena; Presentato, Alessandro; Turner, Raymond J

    2018-02-25

    In the last 15 years, the exploitation of biological systems (i.e. plants, bacteria, mycelial fungi, yeasts, and algae) to produce metal(loid) (Me)-based nanomaterials has been evaluated as eco-friendly and a cost-effective alternative to the chemical synthesis processes. Although the biological mechanisms of biogenic Me-nanomaterial (Bio-Me-nanomaterials) production are not yet completely elucidated, a key advantage of such bio-nanostructures over those chemically synthesized is related to their natural thermodynamic stability, with several studies ascribed to the presence of an organic layer surrounding these Bio-Me-nanostructures. Different macromolecules (e.g. proteins, peptides, lipids, DNA, and polysaccharides) or secondary metabolites (e.g. flavonoids, terpenoids, glycosides, organic acids, and alkaloids) naturally produced by organisms have been indicated as main contributors to the stabilization of Bio-Me-nanostructures. Nevertheless, the chemical-physical mechanisms behind the ability of these molecules in providing stability to Bio-Me-nanomaterials are unknown. In this context, transposing the stabilization theory of chemically synthesized Me-nanomaterials (Ch-Me-nanomaterials) to biogenic materials can be used towards a better comprehension of macromolecules and secondary metabolites role as stabilizing agents of Bio-Me-nanomaterials. According to this theory, nanomaterials are generally featured by high thermodynamic instability in suspension, due to their high surface area and surface energy. This feature leads to the necessity to stabilize chemical nanostructures, even during or directly after their synthesis, through the development of (i) electrostatic, (ii) steric, or (iii) electrosteric interactions occurring between molecules and nanomaterials in suspension. Based on these three mechanisms, this review is focused on parallels between the stabilization of biogenic or chemical nanomaterials, suggesting which chemical-physical mechanisms may be

  19. Dielectric relaxations in non-metallic materials related to Y-Ba-Cu-O superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Bennani, H.; Pilet, J.C. (Lab. Instrumentation, Rennes-1 Univ., 35 (France)); Guilloux-Viry, M.; Perrin, C.; Perrin, A.; Sergent, M. (Lab. de Chimie Minerale B, C.N.R.S., 35 - Rennes (France))

    1990-10-15

    In relation with high Tc superconducting material studies, dielectric measurements have been carried out, in the frequency range 10 Hz - 100 kHz, on two powdered compounds belonging to the Y-Ba-Cu-O system. The non-metallic tetragonal phases YBa{sub 2}Cu{sub 3}O{sub 6+x} exhibit dielectric relaxations: for the studied samples (x<0.4) the activation energy U is observed in the range 0.5related to the presence of electrical dipoles due to the local dissymmetries induced by oxygen vacancies in the Cu-O chains. The insulating green phase Y{sub 2}BaCuO{sub 5} has a lower activation energy U {approx equal} 0.4 eV and an entropy factor A {approx equal} 10{sup 10} Hz. A second dielectric relaxation has been detected at higher temperature, near 400 K. Additional measurements to 77 K at 1 MHz give a value of dielectric constant {epsilon}'=3 and a low loss factor tg{delta}=10{sup -3}: this latter value is comparable to the one of lanthanum gallate recently proposed as a substrate for high frequency uses. This result enhances the previously reported potential interest of this material as substrate or buffer layer for preparation of superconducting thin films for high frequency applications. (orig.).

  20. Quantitation of maxillary remodeling. 1. A description of osseous changes relative to superimposition on metallic implants.

    Science.gov (United States)

    Baumrind, S; Korn, E L; Ben-Bassat, Y; West, E E

    1987-01-01

    Lateral skull radiographs for a set of 31 human subjects were examined using computer-aided methods in an attempt to quantify modal trends of maxillary remodeling during the mixed dentition and adolescent growth periods. Cumulative changes in position of anterior nasal spine (ANS), posterior nasal spine (PNS), and Point A are reported at annual intervals relative to superimposition on previously placed maxillary metallic implants. This in vivo longitudinal study confirms at a high level of confidence earlier findings by Enlow, Björk, Melsen, and others to the effect that the superior surface of the maxilla remodels downward during the period of growth and development being investigated. However, the inter-individual variability is relatively large, the mean magnitudes of change are relatively small, and the rate of change appears to diminish by 13.5 years. For the 19 subjects for whom data were available for the time interval from 8.5 to 15.5 years, mean downward remodeling at PNS was 2.50 mm with a standard deviation of 2.23 mm. At ANS, corresponding mean value was 1.56 mm with a standard deviation of 2.92 mm. Mean rotation of the ANS-PNS line relative to the implant line was 1.1 degree in the "forward" direction. However, this rotational change was particularly variable with a standard deviation of 4.6 degrees and a range of 11.3 degrees "forward" to 6.7 degrees "backward." The study provides strong evidence that the palate elongates anteroposteriorly mainly by the backward remodeling of structures located posterior to the region in which the implants were placed. There is also evidence that supports the idea of modal resorptive remodeling at ANS and PNS, but here the data are somewhat more equivocal. It appears likely, but not certain, that there are real differences in the modal patterns of remodeling between treated and untreated subjects. Because of problems associated with overfragmentation of the sample, sex differences were not investigated.

  1. Heavy metals in wild house mice from coal-mining areas of Colombia and expression of genes related to oxidative stress, DNA damage and exposure to metals.

    Science.gov (United States)

    Guerrero-Castilla, Angélica; Olivero-Verbel, Jesús; Marrugo-Negrete, José

    2014-03-01

    Coal mining is a source of pollutants that impact on environmental and human health. This study examined the metal content and the transcriptional status of gene markers associated with oxidative stress, metal transport and DNA damage in livers of feral mice collected near coal-mining operations, in comparison with mice obtained from a reference site. Mus musculus specimens were caught from La Loma and La Jagua, two coal-mining sites in the north of Colombia, as well as from Valledupar (Cesar Department), a city located 100km north of the mines. Concentrations in liver tissue of Hg, Zn, Pb, Cd, Cu and As were determined by differential stripping voltammetry, and real-time PCR was used to measure gene expression. Compared with the reference group (Valledupar), hepatic concentrations of Cd, Cu and Zn were significantly higher in animals living near mining areas. In exposed animals, the mRNA expression of NQ01, MT1, SOD1, MT2, and DDIT3 was 4.2-, 7.3-, 2.5-, 4.6- and 3.4-fold greater in coal mining sites, respectively, than in animals from the reference site (pmining may generate pollutants that could affect the biota, inducing the transcription of biochemical markers related to oxidative stress, metal exposure, and DNA damage. These changes may be in part linked to metal toxicity, and could have implications for the development of chronic disease. Therefore, it is essential to implement preventive measures to minimize the effects of coal mining on its nearby environment, in order to protect human health. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Modeling Ethanol Decomposition on Transition Metals: A Combined Application of Scaling and Bronsted-Evans-Polanyi Relations

    DEFF Research Database (Denmark)

    Ferrin, P.; Simonetti, D.; Kandoi, S.

    2009-01-01

    calculations necessary to describe trends in activity and selectivity across metal and alloy surfaces, thus extending the reach of DFT to more complex systems. In-this work, the well-known family of Bronsted-Evans-Polanyi (BEP) correlations, connecting minima with maxima in the potential energy surface...... on a subset of these surfaces are calculated. Experiments on supported catalysts verify that this simple model is reasonably accurate in describing reactivity trends across metals, suggesting that the combination of BEP and scaling relations may substantially reduce the cost of DFT calculations required...

  3. Dining at the periodic table: metals concentrations as they relate to recycling.

    Science.gov (United States)

    Johnson, Jeremiah; Harper, E M; Lifset, Reid; Graedel, T E

    2007-03-01

    A correlation between the prices of a variety of substances and their dilutions in their initial matrices was shown in 1959 by T.K. Sherwood. The research presented here shows that the relationship holds for engineering metals today, which we termed the metals-specific Sherwood plot. The concentrations of metals in products (e.g., printed wiring boards and automobiles) and waste streams (e.g., municipal solid waste, and construction and demolition debris) were plotted with this correlation. In addition, for the products and waste streams that undergo disassembly at end-of-life, the metals concentrations of the disassembled components were also plotted. It was found that most of the metals that are currently targeted for recycling have post-disassembly concentrations that lie above the metals-specific Sherwood plot (i.e., have concentrations that are more enriched than minimum profitable ore grades). This suggests that material concentration plays a role in the viability of recycling at end-of-life. As products grow in complexity and the variety of materials used, analyses such as this one provide insight for policymakers and those interested in material sustainability into macro-level trends of material use and future recycling practices.

  4. Monitoring Heavy Metal Contents with Sphagnum Junghuhnianum Moss Bags in Relation to Traffic Volume in Wuxi, China

    Directory of Open Access Journals (Sweden)

    Rong Hu

    2018-02-01

    Full Text Available Despite its small size, a moss bag can reveal the different temporal and spatial deposition patterns of pollutants at a particular site; therefore, researchers can use moss bags to determine pollution sources and to put forward strategies for pollution control. Although the use of moss bags to monitor atmospheric pollution has been widely reported in Europe, there are few such empirical studies in China. Thus, in this study, bags containing the moss Sphagnum junghuhnianum were used to assess the concentrations of heavy metals (chromium (Cr, copper (Cu, lead (Pb, vanadium (V, and zinc (Zn at five sampling sites (four roads and a forest park during the summer and winter of 2012. According to the relative accumulation factor (RAF and contamination factor (CF results, pollution in winter was heavier than that in summer, and Cr was found to be the most contaminating, having the highest mean CF. There was a significant positive correlation (p < 0.05 between traffic volume and concentration for three heavy metals (Cr, Cu, and V in winter, whereas a significant positive correlation (p < 0.05 was observed between traffic volume and concentrations for four heavy metal elements (Cr, Pb, V, and Zn in summer, indicating a close relationship between heavy metal contents and traffic volume. Although there was substantial variation in the concentrations of the five heavy metals in the moss bags, significant correlations between heavy metals suggested that the contaminants originated from a common source, namely vehicle emissions. The results demonstrated that the four roads were subject to different degrees of pollution depending on the volume of traffic using each road. Therefore, the results of this study suggest that traffic volume is a major reason for heavy metal pollution.

  5. Monitoring Heavy Metal Contents with Sphagnum Junghuhnianum Moss Bags in Relation to Traffic Volume in Wuxi, China.

    Science.gov (United States)

    Hu, Rong; Yan, Yun; Zhou, Xiaoli; Wang, Yanan; Fang, Yanming

    2018-02-22

    Despite its small size, a moss bag can reveal the different temporal and spatial deposition patterns of pollutants at a particular site; therefore, researchers can use moss bags to determine pollution sources and to put forward strategies for pollution control. Although the use of moss bags to monitor atmospheric pollution has been widely reported in Europe, there are few such empirical studies in China. Thus, in this study, bags containing the moss Sphagnum junghuhnianum were used to assess the concentrations of heavy metals (chromium (Cr), copper (Cu), lead (Pb), vanadium (V), and zinc (Zn)) at five sampling sites (four roads and a forest park) during the summer and winter of 2012. According to the relative accumulation factor (RAF) and contamination factor (CF) results, pollution in winter was heavier than that in summer, and Cr was found to be the most contaminating, having the highest mean CF. There was a significant positive correlation ( p heavy metals (Cr, Cu, and V) in winter, whereas a significant positive correlation ( p heavy metal elements (Cr, Pb, V, and Zn) in summer, indicating a close relationship between heavy metal contents and traffic volume. Although there was substantial variation in the concentrations of the five heavy metals in the moss bags, significant correlations between heavy metals suggested that the contaminants originated from a common source, namely vehicle emissions. The results demonstrated that the four roads were subject to different degrees of pollution depending on the volume of traffic using each road. Therefore, the results of this study suggest that traffic volume is a major reason for heavy metal pollution.

  6. A research program in determination of heavy metals in sediments and benthic species in relation to nuclear power plant operation

    Science.gov (United States)

    Phelps, H. L.

    1984-01-01

    Heavy metals in the estuarine environment can be toxic to fish and shellfish early life history stages and concentrations build up to levels of concern in marketable shellfish. The present survey was begun just before startup in 1974 of the 1900 megawatt Calvert Cliffs Nuclear Power Plant on the Chesapeake Bay in order to assess and understand factors relating to heavy metal accumulation in estuarine biota. Oysters were collected in large numbers at test and reference sites in June 1974 to 77 and individually analyzed for copper and zinc. Oyster copper and zinc concentrations were correlated with salinity read at time of collection. The relationship of oyster age to metal concentration was examined with two sets of oysters of known age and genetic origin (laboratory spawned). Copper sorption by typical mid Bay sediments, and field studies on cadmium concentrations in sediments were examined.

  7. Relation between leaching characteristics of heavy metals and physical properties of fly ashes from typical municipal solid waste incinerators.

    Science.gov (United States)

    Ni, Peng; Li, Hailong; Zhao, Yongchun; Zhang, Junying; Zheng, Chuguang

    2017-09-01

    Due to the alkalinity and high concentration of potentially hazardous heavy metals, fly ash from a municipal solid waste (MSW) incinerator is classified as hazardous waste, which should be of particular concern. Physical and chemical characterizations of the contrasted fly ashes were investigated to explore the relation between leaching characteristics of heavy metals and physical properties of fly ashes. The results showed that CaClOH, NaCl, Ca(OH) 2 , KCl and SiO 2 were primary mineral compositions in the MSWI fly ashes, and the particle size distribution of fly ash ranged between 10 μm and 300 μm. The smaller the particle size distribution of fly ash, the larger the BET-specific surface area, which was beneficial to the leaching of heavy metals. As a result of various pores, it easily accumulated heavy metals as well. The leaching tests exhibited a high leachability of heavy metals and the leaching concentration of Pb in almost all of the fly ash samples went far beyond the Standard for Pollution Control on the Landfill Site of Municipal Solid Waste. Thereupon, it is necessary to establish proper disposal systems and management strategies for environmental protection based on the characteristics of MSW incineration (MSWI) fly ash in China.

  8. Multi-objective Optimization of Friction Welding Process Parameters using Grey Relational Analysis for Joining Aluminium Metal Matrix Composite

    Directory of Open Access Journals (Sweden)

    Sreenivasan KONGANAPURAM SUNDARARAJAN

    2018-05-01

    Full Text Available Aluminium metal matrix composites has gained importance in recent time because of its improved mechanical and metallurgical properties. The welding of aluminium metal matrix composites using conventional welding process has got many demerits so in order to overcome them a solid state welding process is to be employed. To achieve a good strength weld in the aluminium metal matrix composite bars an efficient and most preferred technique is friction welding. In this work the aluminium metal matrix composite AA7075 + 10 % vol SiC-T6 is selected and friction welded. The combination of friction welding process parameters such as spindle speed, friction pressure, upset pressure and burn-off- length for joining the AA7075 + 10 % vol SiCP-T6 metal matrix composite bars are selected by Taguchi’s design of experiment. The optimum friction welding parameters were determined for achieving improved ultimate tensile strength and the hardness using grey relational analysis. A combined grey relational grade is found from the determined grey relational coefficient of the output responses and the optimum friction welding process parameters were obtained as spindle speed – 1200 rpm, friction pressure – 100 MPa, upset pressure – 250 MPa, Burn-off-Length – 2 mm. Analysis of variance (ANOVA performed shows that the friction pressure is the most significant friction welding parameter that influences the both the ultimate tensile strength and hardness of friction welded AA7075 + 10 % volSiCP-T6 joints. The fractured surface under microstructure study also revealed good compliance with the grey relational grade result. DOI: http://dx.doi.org/10.5755/j01.ms.24.2.17725

  9. NONLINEAR COLOR-METALLICITY RELATIONS OF GLOBULAR CLUSTERS. III. ON THE DISCREPANCY IN METALLICITY BETWEEN GLOBULAR CLUSTER SYSTEMS AND THEIR PARENT ELLIPTICAL GALAXIES

    International Nuclear Information System (INIS)

    Yoon, Suk-Jin; Lee, Sang-Yoon; Cho, Jaeil; Kim, Hak-Sub; Chung, Chul; Kim, Sooyoung; Lee, Young-Wook; Blakeslee, John P.; Peng, Eric W.; Sohn, Sangmo T.

    2011-01-01

    One of the conundrums in extragalactic astronomy is the discrepancy in observed metallicity distribution functions (MDFs) between the two prime stellar components of early-type galaxies—globular clusters (GCs) and halo field stars. This is generally taken as evidence of highly decoupled evolutionary histories between GC systems and their parent galaxies. Here we show, however, that new developments in linking the observed GC colors to their intrinsic metallicities suggest nonlinear color-to-metallicity conversions, which translate observed color distributions into strongly peaked, unimodal MDFs with broad metal-poor tails. Remarkably, the inferred GC MDFs are similar to the MDFs of resolved field stars in nearby elliptical galaxies and those produced by chemical evolution models of galaxies. The GC MDF shape, characterized by a sharp peak with a metal-poor tail, indicates a virtually continuous chemical enrichment with a relatively short timescale. The characteristic shape emerges across three orders of magnitude in the host galaxy mass, suggesting a universal process of chemical enrichment among various GC systems. Given that GCs are bluer than field stars within the same galaxy, it is plausible that the chemical enrichment processes of GCs ceased somewhat earlier than that of the field stellar population, and if so, GCs preferentially trace the major, vigorous mode of star formation events in galactic formation. We further suggest a possible systematic age difference among GC systems, in that the GC systems in more luminous galaxies are older. This is consistent with the downsizing paradigm whereby stars of brighter galaxies, on average, formed earlier than those of dimmer galaxies; this additionally supports the similar nature shared by GCs and field stars. Although the sample used in this study (the Hubble Space Telescope Advanced Camera for Surveys/Wide Field Channel, WFPC2, and WFC3 photometry for the GC systems in the Virgo galaxy cluster) confines our

  10. The MOSDEF Survey: A Stellar Mass–SFR–Metallicity Relation Exists at z ∼ 2.3

    Science.gov (United States)

    Sanders, Ryan L.; Shapley, Alice E.; Kriek, Mariska; Freeman, William R.; Reddy, Naveen A.; Siana, Brian; Coil, Alison L.; Mobasher, Bahram; Davé, Romeel; Shivaei, Irene; Azadi, Mojegan; Price, Sedona H.; Leung, Gene; Fetherholf, Tara; de Groot, Laura; Zick, Tom; Fornasini, Francesca M.; Barro, Guillermo

    2018-05-01

    We investigate the nature of the relation among stellar mass, star formation rate, and gas-phase metallicity (the {M}* –SFR–Z relation) at high redshifts using a sample of 260 star-forming galaxies at z ∼ 2.3 from the MOSDEF survey. We present an analysis of the high-redshift {M}* –SFR–Z relation based on several emission-line ratios for the first time. We show that a {M}* –SFR–Z relation clearly exists at z ∼ 2.3. The strength of this relation is similar to predictions from cosmological hydrodynamical simulations. By performing a direct comparison of stacks of z ∼ 0 and z ∼ 2.3 galaxies, we find that z ∼ 2.3 galaxies have ∼0.1 dex lower metallicity at fixed {M}* and SFR. In the context of chemical evolution models, this evolution of the {M}* –SFR–Z relation suggests an increase with redshift of the mass-loading factor at fixed {M}* , as well as a decrease in the metallicity of infalling gas that is likely due to a lower importance of gas recycling relative to accretion from the intergalactic medium at high redshifts. Performing this analysis simultaneously with multiple metallicity-sensitive line ratios allows us to rule out the evolution in physical conditions (e.g., N/O ratio, ionization parameter, and hardness of the ionizing spectrum) at fixed metallicity as the source of the observed trends with redshift and with SFR at fixed {M}* at z ∼ 2.3. While this study highlights the promise of performing high-order tests of chemical evolution models at high redshifts, detailed quantitative comparisons ultimately await a full understanding of the evolution of metallicity calibrations with redshift. Based on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation.

  11. Macrobenthic community in the Douro estuary: relations with trace metals and natural sediment characteristics

    International Nuclear Information System (INIS)

    Mucha, A.P.; Vasconcelos, M.T.S.D.; Bordalo, A.A.

    2003-01-01

    This study used a novel approach to detect a clear signature of metal contamination and biological impacts in an estuary. - The relationship between macrobenthic community structure and natural characteristics of sediment and trace metal contamination were studied in the lower Douro estuary (Portugal, NW, Iberian Peninsula), using an innovative threefold approach (SQG, Sediment Quality Guidelines), metal normalization to Fe, and macrobenthic community structure. This study allowed detection of a clear signature of anthropogenic contamination, in terms of Zn, Cu, Pb, and Cr in the north bank of the estuary, which experiences high urban pressure. Using the SQG approach, metal concentrations above ERM (effects range--median) were observed only at one sampling station, but several stations had levels above ERL (effects range-low). The macrobenthic community had a low diversity, with only 19 species found in the entire estuarine area, dominated by opportunistic species. The granulometric distribution of the sediments (estimated from the combination of organic matter, Fe and Al) seemed to be the major structuring factor for the communities, establishing the natural macrobenthic distribution pattern. The metals (Zn, Cu, Pb, and Cr) seemed to act as a disturbing factor over the natural distribution, with deleterious consequences for the macrobenthic communities

  12. Improvements in or relating to the production of metal-containing material in particulate form

    International Nuclear Information System (INIS)

    Woodhead, J.L.; Scott, K.T.B.; Ball, P.W.

    1977-01-01

    The process described refers mainly to production of the material in the form of very small spheres. It comprises forming a metal compound-containing gel precipitate by mixing a solution or sol of the metal compound with a soluble organic polymer and contacting the mixture with a precipitating reagent to precipitate the metal as an insoluble compound bound with the polymer. The precipitate is then subjected in the liquid phase to a breaking down and dispersing process to produce an intermediate product suitable for spray drying, and the intermediate product is spray dried to form the particulate product. The breaking down and dispersing process may be performed by means of a colloid mill or vibratory stirrer. Examples of application of the process are described. (U.K.)

  13. Heavy metals uptake by sonicated activated sludge: Relation with floc surface properties

    International Nuclear Information System (INIS)

    Laurent, Julien; Casellas, Magali; Dagot, Christophe

    2009-01-01

    The effects of sonication of activated sludge on heavy metal uptake were in a first time investigated in respect with potential modifications of floc surface properties. The treatment led to the simultaneous increase of specific surface area and of the availability of negative and/or hydrophilic sites. In parallel, organic matter was released in the soluble fraction. Sorption isotherms of cadmium and copper showed that uptake characteristics and mechanisms were highly dependent on both heavy metal species and specific energy supplied. The increase of both specific surface area and fixation sites availability led to the increase of Cd(II) uptake. For Cu(II), organic matter released in soluble phase during the treatment seemed to act as a ligand and to limit adsorption on flocs surface. Three different heavy metals uptake mechanisms have been identified: proton exchange, ion exchange and (co)precipitation

  14. The galaxy population of Abell 1367: the stellar mass-metallicity relation

    Science.gov (United States)

    Mouhcine, M.; Kriwattanawong, W.; James, P. A.

    2011-04-01

    Using wide baseline broad-band photometry, we analyse the stellar population properties of a sample of 72 galaxies, spanning a wide range of stellar masses and morphological types, in the nearby spiral-rich and dynamically young galaxy cluster Abell 1367. The sample galaxies are distributed from the cluster centre out to approximately half the cluster Abell radius. The optical/near-infrared colours are compared with simple stellar population synthesis models from which the luminosity-weighted stellar population ages and metallicities are determined. The locus of the colours of elliptical galaxies traces a sequence of varying metallicity at a narrow range of luminosity-weighted stellar ages. Lenticular galaxies in the red sequence, however, exhibit a substantial spread of luminosity-weighted stellar metallicities and ages. For red-sequence lenticular galaxies and blue cloud galaxies, low-mass galaxies tend to be on average dominated by stellar populations of younger luminosity-weighted ages. Sample galaxies exhibit a strong correlation between integrated stellar mass and luminosity-weighted stellar metallicity. Galaxies with signs of morphological disturbance and ongoing star formation activity, tend to be underabundant with respect to passive galaxies in the red sequence of comparable stellar masses. We argue that this could be due to tidally driven gas flows towards the star-forming regions, carrying less enriched gas and diluting the pre-existing gas to produce younger stellar populations with lower metallicities than would be obtained prior to the interaction. Finally, we find no statistically significant evidence for changes in the luminosity-weighted ages and metallicities for either red-sequence or blue-cloud galaxies, at fixed stellar mass, with location within the cluster. We dedicate this work to the memory of our friend and colleague C. Moss who died suddenly recently.

  15. Age-Related Uptake of Heavy Metals in Human Spinal Interneurons.

    Directory of Open Access Journals (Sweden)

    Roger Pamphlett

    Full Text Available Toxic heavy metals have been implicated in the loss of spinal motoneurons in amyotrophic lateral sclerosis/motor neuron disease (ALS/MND. Motoneuron loss in the spinal anterior horn is severe in ALS/MND at the time of death, making this tissue unsuitable for examination. We therefore examined spinal cords of people without muscle weakness to look for any presence of heavy metals that could make these neurons susceptible to damage. Spinal cord samples from 50 individuals aged 1-95 y who had no clinical or histopathological evidence of spinal motoneuron loss were studied. Seven μm formalin-fixed paraffin-embedded sections were stained for heavy metals with silver nitrate autometallography (AMGHM which detects intracellular mercury, silver or bismuth. Neurons in the spinal cord were classified as interneurons or α-motoneurons based on their site and cell body diameter. Spinal interneurons containing heavy metals were present in 8 of 24 people (33% aged 61-95 y, but not at younger ages. These AMGHM interneurons were most numerous in the lumbar spinal cord, with moderate numbers in the caudal cervical cord, few in the rostral cervical cord, and almost none in the thoracic cord. All people with AMGHM interneurons had occasional AMGHM staining in α-motoneurons as well. In one man AMGHM staining was present in addition in dorsomedial nucleus and sensory neurons. In conclusion, heavy metals are present in many spinal interneurons, and in a few α-motoneurons, in a large proportion of older people. Damage to inhibitory interneurons from toxic metals in later life could result in excitotoxic injury to motoneurons and may underlie motoneuron injury or loss in conditions such as ALS/MND, multiple sclerosis, sarcopenia and calf fasciculations.

  16. Metal recycling technology and related issues in the United States, a BNFL perspective

    International Nuclear Information System (INIS)

    Bradbury, P.; Dam, S.; Starke, W.

    1995-01-01

    Radioactively contaminated metallic materials comprise a large part of the potential waste products which result from nuclear facility repair, refurbishment, and decommissioning. United States Government (Departments of Energy and Defense) facilities, U.S. nuclear power plants, and other commercial nuclear fuel cycle facilities have large inventories of radioactive scrap metal which could be decontaminated and recycled into useful radioactive and non-radioactive products. Residual radioactivity and recycling criteria is needed to avoid the high cost of disposal and the waste of natural resources. In the United Kingdom, BNFL has decommissioned the gaseous diffusion plant at Capenhurst and has recycled a large fraction of the metallic scrap into the metals market. Other structural materials have also been released as uncontaminated scrap. U.K. release criteria for residual radionuclide contamination have been applied to these operations. A variety of techniques were utilized to size reduce large components, to remove radioactivity, and to survey and release these materials. These methods and the application of release criteria has a direct relationship to methods which would be applicable in the U.S. and in other countries. This paper will describe the specific U.K. technology and experience in the decontamination, recycle, and release of scrap metal. It will also describe the U.S. environment for metal recycle, including the volumes and levels of contamination, and the current and proposed release criteria. Comparisons will be presented between the U.S. and U.K., both in technology and methodology for recycle and in regulatory criteria for residual radioactivity and material release and for ultimate decommissioning. The paper will then provide suggested approaches and criteria for U.S. recycling and decommissioning. (author)

  17. INTERTEXTUAL RELATIONS IN METAL FIRTINA 4 TURAN NOVEL METAL FIRTINA 4 TURAN ROMANINDA METİNLERARASI İLİŞKİLER

    Directory of Open Access Journals (Sweden)

    Mehmet SOĞUKÖMEROĞULLARI

    2012-06-01

    Full Text Available Tradition is employed in the course of progress of genre of novel, which is introduced to Turkish literature through translations from Western Literature. Especially, the way that Ahmet Mithat Efendi followed provides basis fort he progress of the novel of that kind. In modern thought, corresponding sense of that way is intertextual relations. Briefly, intertextual relations that refer to the gathering and the fashion of redesigning of other texts echo in Metal Fırtına 4 Turan, the subject matter of this study. Metal Fırtına 4 Turan consists of the gathering and reinterpretation of such elements of especially folklore, mythology, and folk literature as Shamanism, Ergenekon epic, wolf, and end of the world or Kalgançı Çak legend. Those elements in the novel constitute the subject matter of this article. Türk edebiyatına Batı edebiyatından çevirilerle giren roman türünün gelişim aşamasında gelenekten faydalanılır. Özellikle Ahmet Mithat Efendi’nin izlediği yol bu yönde romanın ilerlemesine zemin hazırlar. Bu tarzın modern düşüncede karşılığı metinlerarası ilişkilerdir. Kısaca, bir metnin başka metinlerin bir araya gelmesi ve yeniden tasarlanması şeklinde tanımlanabilecek olan metinlerarası ilişkiler, inceleme konumuz olan Metal Fırtına 4 Turan romanına da yansır. Özellikle folklor, mitoloji veya halk edebiyatı ögelerinden Şamanizm, Ergenekon destanı, kurt ve dünyanın sonu veya Kalgançı Çak efsanesinin bir araya getirilerek yeniden yorumlanmasıyla oluşan Metal Fırtına 4 Turan romanındaki bu unsurlar makalenin konusunu teşkil eder.

  18. Monitoring of heavy metals in selected Water Supply Systems in Poland, in relation to current regulations

    Science.gov (United States)

    Szuster-Janiaczyk, Agnieszka; Zeuschner, Piotr; Noga, Paweł; Skrzypczak, Marta

    2018-02-01

    The study presents an analysis of water quality monitoring in terms of the content of heavy metals, which is conducted in three independent water supply systems in Poland. The analysis showed that the monitoring of heavy metals isn't reliable - both the quantity of tested water samples and the location of the monitoring points are the problem. The analysis of changes in water quality from raw water to tap water was possible only for one of the analysed systems and indicate a gradual deterioration of water quality, although still within acceptable limits of legal regulations.

  19. A Review of Flood-Related Storage and Remobilization of Heavy Metal Pollutants in River Systems

    Czech Academy of Sciences Publication Activity Database

    Ciszewski, D.; Matys Grygar, Tomáš

    2016-01-01

    Roč. 227, č. 7 (2016), s. 227-239 ISSN 0049-6979 R&D Projects: GA ČR(CZ) GA15-00340S Institutional support: RVO:61388980 Keywords : River * Sediment * Heavy metals * Mobilization * Pollution Subject RIV: DD - Geochemistry Impact factor: 1.702, year: 2016

  20. Transition-metal derivatives of nido-boranes and some related species

    International Nuclear Information System (INIS)

    Greenwood, N.N.; Kennedy, J.D.

    1982-01-01

    This paper reviews the wide variety of metalloboranes that have been made by the reactions of transitional-metal compounds with nido-boranes or their anions. The authors concentrate on preparative and structural aspects and discuss presumed reaction mechanisms or postulated modes of bonding. Monoboron, diboron, triboron, tetraboron, pentaboron, hexaboron, nonaboron, decaboron, octadecaboron, and icosaboron compounds are discussed

  1. Assessment of heavy metal pollution in Ghana by nuclear-related techniques

    International Nuclear Information System (INIS)

    Akoto Bamford, S.; Aboh, I.; Osae, E.

    1992-01-01

    X-ray fluorescence analysis and atomic absorption spectrophotometry was used to test for the presence and levels of heavy metals in solid wastes discharged from the gold mining industry. This report contains the results of the analysis of vegetation and river sediment samples. 2 refs, 2 tabs

  2. Binary and ternary carbides and nitrides of the transition metals and their phase relations

    International Nuclear Information System (INIS)

    Holleck, H.

    1981-01-01

    The occurrance and the structure of the binary and ternary transition metal carbides and nitrides are described. Phase diagrams are assessed for most of the binary and ternary systems. Many ternary phase diagrams are published in this report for the first time. (orig.) [de

  3. The age-metallicity relation in the solar neighbourhood from a pilot sample of white dwarf-main sequence binaries

    OpenAIRE

    Rebassa-Mansergas, A.; Anguiano, B.; García-Berro, E.; Freeman, K. C.; Cojocaru, R.; Manser, C. J.; Pala, A. F.; Gänsicke, B. T.; Liu, X. -W.

    2016-01-01

    The age–metallicity relation (AMR) is a fundamental observational constraint for understanding how the Galactic disc formed and evolved chemically in time. However, there is not yet an agreement on the observational properties of the AMR for the solar neighbourhood, primarily due to the difficulty in obtaining accurate stellar ages for individual field stars. We have started an observational campaign for providing the much needed observational input by using wide white-dwarf–main-sequence (WD...

  4. A randomized, controlled intervention of machine guarding and related safety programs in small metal-fabrication businesses.

    Science.gov (United States)

    Parker, David L; Brosseau, Lisa M; Samant, Yogindra; Xi, Min; Pan, Wei; Haugan, David

    2009-01-01

    Metal fabrication employs an estimated 3.1 million workers in the United States. The absence of machine guarding and related programs such as lockout/tagout may result in serious injury or death. The purpose of this study was to improve machine-related safety in small metal-fabrication businesses. We used a randomized trial with two groups: management only and management-employee. We evaluated businesses for the adequacy of machine guarding (machine scorecard) and related safety programs (safety audit). We provided all businesses with a report outlining deficiencies and prioritizing their remediation. In addition, the management-employee group received four one-hour interactive training sessions from a peer educator. We evaluated 40 metal-fabrication businesses at baseline and 37 (93%) one year later. Of the three nonparticipants, two had gone out of business. More than 40% of devices required for adequate guarding were missing or inadequate, and 35% of required safety programs and practices were absent at baseline. Both measures improved significantly during the course of the intervention. No significant differences in changes occurred between the two intervention groups. Machine-guarding practices and programs improved by up to 13% and safety audit scores by up to 23%. Businesses that added safety committees or those that started with the lowest baseline measures showed the greatest improvements. Simple and easy-to-use assessment tools allowed businesses to significantly improve their safety practices, and safety committees facilitated this process.

  5. Assessment of levels and 'health-effects' of airborne particulate matter in mining, metal refining and metal working industries using nuclear and related analytical techniques

    International Nuclear Information System (INIS)

    2008-01-01

    The International Atomic Energy Agency (IAEA) has been supporting, over the years, several coordinated research programmes (CRPs) on various research topics related to environmental issues impacting human health. The primary aim of these CRPs has been to help enhance the research and development capabilities in the Member States, particularly among developing countries; to identify the sources of various environmental contaminants and evaluate their fate; and to provide for the basis of improved health among human populations by the use of nuclear and related analytical techniques. The CRP on Assessment of Levels and Health-Effects of Airborne Particulate Matter in Mining, Metal Refining and Metal Working Industries using nuclear and related analytical techniques focused on improving the competence for research on workplace monitoring in a variety of industrial environments. The personal monitoring of the APM (airborne particulate matter) of the exposed workforce was carried out for the first time by many participants. Nuclear and related analytical techniques, including the application of proton micro-beam, were used to generate the trace element concentration profiles in various biomarkers tissues of the exposed workers. The quality assurance/quality control (QA/QC) aspects related to the CRP were addressed through intercomparison analyses of APM on filter paper samples and freeze dried human urine samples to generate validated data. These data have helped to generate correlations between the occupational exposure measured and the magnitude of the biological response. Such new information is essential to evolve procedures to considerably reduce/eliminate the pollutants in the workplace environment and to make informed decisions on the evolution of standards in working environments aimed at preserving the health of workers. The purpose of this TECDOC is to provide an overview of the activities performed under the CRP by the participants. The overall achievements

  6. Related Structure Characters and Stability of Structural Defects in a Metallic Glass.

    Science.gov (United States)

    Niu, Xiaofeng; Feng, Shidong; Pan, Shaopeng

    2018-03-22

    Structural defects were investigated by a recently proposed structural parameter, quasi-nearest atom (QNA), in a modeled Zr 50 Cu 50 metallic glass through molecular dynamics simulations. More QNAs around an atom usually means that more defects are located near the atom. Structural analysis reveals that the spatial distribution of the numbers of QNAs displays to be clearly heterogeneous. Furthermore, QNA is closely correlated with cluster connections, especially four-atom cluster connections. Atoms with larger coordination numbers usually have less QNAs. When two atoms have the same coordination number, the atom with larger five-fold symmetry has less QNAs. The number of QNAs around an atom changes rather frequently and the change of QNAs might be correlated with the fast relaxation metallic glasses.

  7. A study on the treatment process of industrial wastewater related to heavy metal wastewater

    International Nuclear Information System (INIS)

    Park, J. J.; Shin, J. M.; Kim, J. H.; Yang, M. S.; Kim, M. J.; Son, J. S.; Park, H. S.

    1999-08-01

    The supernatant from metal wastewater by using magnesium hydroxide and dolomite was used to treat dyeing wastewater. In the case of magnesium hydroxide. In the case of magnesium hydroxide, the optimum dosage was 10 % (v/v) for supernatant A and 3 % (v/v) for separation B. Color turbidity and COD removal was 99 to 100 % , 85 to 97 % and 43 to 53 %, respectively. In the case of dolomite, the optimum dosage was 30 % (v/v) for supernatant A and 3% for supernatant B. Color, turbidity and COD removal was 96 to 99 %, 62 to 91 % and 52 to 53 %, respectively. In dyeing wastewater treatment by using supernatant from metal wastewater, the cost of chemicals was reduced by about 80 %

  8. Related Structure Characters and Stability of Structural Defects in a Metallic Glass

    Science.gov (United States)

    Niu, Xiaofeng; Feng, Shidong; Pan, Shaopeng

    2018-01-01

    Structural defects were investigated by a recently proposed structural parameter, quasi-nearest atom (QNA), in a modeled Zr50Cu50 metallic glass through molecular dynamics simulations. More QNAs around an atom usually means that more defects are located near the atom. Structural analysis reveals that the spatial distribution of the numbers of QNAs displays to be clearly heterogeneous. Furthermore, QNA is closely correlated with cluster connections, especially four-atom cluster connections. Atoms with larger coordination numbers usually have less QNAs. When two atoms have the same coordination number, the atom with larger five-fold symmetry has less QNAs. The number of QNAs around an atom changes rather frequently and the change of QNAs might be correlated with the fast relaxation metallic glasses. PMID:29565298

  9. Multicharged ion-induced emission from metal- and insulator surfaces related to magnetic fusion research

    Energy Technology Data Exchange (ETDEWEB)

    Winter, H.P. [Technische Univ., Vienna (Austria). Inst. fuer Allgemeine Physik

    1997-01-01

    The edge region of magnetically confined plasmas in thermonuclear fusion experiments couples the hot plasma core with the cold first wall. We consider the dependence of plasma-wall interaction processes on edge plasma properties, with particular emphasis on the role of slow multicharged ions (MCI). After a short survey on the physics of slow MCI-surface interaction we discuss recent extensive studies on MCI-induced electron emission from clean metal surfaces conducted at impact velocities << 1 a.u., from which generally reliable total electron yields can be obtained. We then demonstrate the essentially different role of the MCI charge for electron emission from metallic and insulator surfaces, respectively. Furthermore, we present recent results on slow MCI-induced `potential sputtering` of insulators which, in contrast to the well established kinetic sputtering, already occurs at very low ion impact energy and strongly increases with the MCI charge state. (J.P.N.). 55 refs.

  10. Relation between the degree of lung pollution by air pollution and heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Kawai, H; Endo, R; Takemoto, K

    1975-04-01

    Human and dog lungs were analyzed for 13 kinds of heavy metals. The human lungs (all of Tokyo citizens) showed a broad range of dust sedimentation, some correlation between the degree of pollution and the amount of cadmium, nickel, and chromium only, and conspicuous individual differences seemingly due to occupation. No correlation was found between the amount of pulmonary metals, and age, or sex. In dog lungs there was no correlation between the local pollution and the amount of iron, copper, zinc, cobalt, and cadmium. Cadmium, nickel, lead, and chromium showed a correlation between local air pollution in human lungs. In dogs obtained in Korea, Ni and Cr were higher than in dog lungs obtained in Jinsen.

  11. Methane oxidation over noble metal catalysts as related to controlling natural gas vehicle exhaust emissions

    International Nuclear Information System (INIS)

    Oh, S.H.; Mitchell, P.J.; Siewert, R.M.

    1992-01-01

    Natural gas has considerable potential as an alternative automotive fuel. This paper reports on methane, the principal hydrocarbon species in natural-gas engine exhaust, which has extremely low photochemical reactivity but is a powerful greenhouse gas. Therefore, exhaust emissions of unburned methane from natural-gas vehicles are of particular concern. This laboratory reactor study evaluates noble metal catalysts for their potential in the catalytic removal of methane from natural-gas vehicle exhaust. Temperature run-up experiments show that the methane oxidation activity decreases in the order Pd/Al 2 O 3 > Rh/Al 2 O 3 > Pt/Al 2 O 3 . Also, for all the noble metal catalysts studied, methane conversion can be maximized by controlling the O 2 concentration of the feedstream at a point somewhat rich (reducing) of stoichiometry

  12. Hair as an indicator of the body burden of metals in relation to age

    International Nuclear Information System (INIS)

    Kostial, K.

    1993-01-01

    Many factors influencing metal deposition in hair are still unknown. Animal experiments were performed to obtain data on the mechanism of transfer of elements into hair and to estimate whether hair retention is influenced by age, sex and chelating agent treatment. Experiments were performed on albino rats (Wistar strain) of different age and sex. Whole body hair (skin included) and organ retention of various elements was determined at different periods of time after intraperitoneal administration of the radioactive isotopes 115m Cd, 203 Hg, 54 Mn, 59 Fe, 65 Zn, 141 Ce, 137 Cs, 203 Pb and 85 Sr. In some experiments DTPA was used for reducing body retention of 155m Cd and 141 Ce and DMPS for reducing 203 Hg retention. Results show that hair and organ retention of elements in rats varies with age, sex and chelation treatment and such changes are specific for each element and can not be generalized. Age as a factor influencing hair retention of metals is likely to be more important for some elements than for others. In kinetic studies we found that due to differences in element distribution and kinetics, the relationship between hair and organ retention at various time intervals varies both with age and the element concerned. Sex influences not only hair but also metal retention and distribution in other organs. (author). 4 refs

  13. Development of 4S and related technologies (2). Long life metallic fuel

    International Nuclear Information System (INIS)

    Yacout, A.M.; Tsuboi, Y.; Ueda, N.

    2009-01-01

    This paper provides an overview of the long life metallic fuel to be used in the 4S reactor. The 4S fuel design is presented and implications of its characteristics on fuel performance are discussed. Main design characteristics include the long fuel life time of 30 years and the wider and longer fuel pins compared to EBR-II and FFTF fuel pins. The LIFE-METAL fuel performance code was used to evaluate the performance of the 4S fuel design. The code has been validated using post irradiation examination data of metallic fuel irradiated in EBR-II. The performance evaluation shows the benign nature of the design. The design enables the fuel to perform adequately during reactor operations without violating any of a conservative set of steady state design criteria. A survey evaluation of the fuel performance is also presented. This performance bounding evaluation took into account possible fuel swelling behavior and cladding temperature range that represents worst case scenarios. The evaluation showed that the fuel maintains its integrity even under those worst case conditions. (author)

  14. Dispersion relation and electron acceleration in the combined circular and elliptical metallic-dielectric waveguide filled by plasma

    Science.gov (United States)

    Abdoli-Arani, A.; Montazeri, M. M.

    2018-04-01

    Two special types of metallic waveguide having dielectric cladding and plasma core including the combined circular and elliptical structure are studied. Longitudinal and transverse field components in the different regions are obtained. Applying the boundary conditions, dispersion relations of the electromagnetic waves in the structures are obtained and then plotted. The acceleration of an injected external relativistic electron in the considered waveguides is studied. The obtained differential equations related to electron motion are solved by the fourth-order Runge-Kutta method. Numerical computations are made, and the results are graphically presented.

  15. Heavy metals in wild boar (Sus scrofa and related lesions

    Directory of Open Access Journals (Sweden)

    A. Zaccaroni

    2003-10-01

    Full Text Available Heavy metals are toxic elements naturally present in the environment which can be bioconcentrated by plants and animals and incorporated into food cycles. Thus the use of wildlife species as monitors is a useful tool to assess environmental pollution. Because of its ethological characteristics, wild boar is highly probable to be exposed to pollution, mainly by heavy metals. These pollutants, when present at high enough concentrations, can induce histological lesion in various tissues. The purpose of the present work was to investigate the levels of five metals (cadmium, copper, iron, lead and zinc in wild boar, Sus scrofa, originating from an Apennine area of Emilia Romagna, Northern Italy, and to evaluate any possible correlation with histological lesions eventually observed. Samples of several organs (liver, heart, kidney, diaphragm, abductor muscle, masseter, eye, testis, brain, lung and spleen were collected from hunted animals during winter 2001. Levels of metals were determined on freeze dried tissues employing microwave wet digestion. Toxicological analysis were performed by atomic absorption spectrophotometry and data expressed on a dry weight basis. Histopatological analyses were performed on fixed samples of the same tissue. Highest mean values were found in kidney for cadmium and copper (7 ± 1 ppm and 30 ± 2.6 ppm respectively and in liver for copper (21.16 ± 3.28 ppm, lead (2139 ± 680.6 ppb, iron (415.92 ± 24.41 ppm and zinc (94.76 ± 6.11 ppm. In all other tissues, mean concentrations of each metal were at low levels, and were comparable one another. A statistical difference was found for iron (p<0.05, copper (p<0.05 and cadmium (p<0.01 in kidney, in testis (p<0.01 for zinc and in liver for copper (p<0.05 and cadmium (p<0.01 as function of age cohorts. When sex was considered, a statistical difference was found for iron in eye, for copper in heart and for cadmium in heart and kidney. Histopatological analysis allowed

  16. Alkali Metal Ion Complexes with Phosphates, Nucleotides, Amino Acids, and Related Ligands of Biological Relevance. Their Properties in Solution.

    Science.gov (United States)

    Crea, Francesco; De Stefano, Concetta; Foti, Claudia; Lando, Gabriele; Milea, Demetrio; Sammartano, Silvio

    2016-01-01

    Alkali metal ions play very important roles in all biological systems, some of them are essential for life. Their concentration depends on several physiological factors and is very variable. For example, sodium concentrations in human fluids vary from quite low (e.g., 8.2 mmol dm(-3) in mature maternal milk) to high values (0.14 mol dm(-3) in blood plasma). While many data on the concentration of Na(+) and K(+) in various fluids are available, the information on other alkali metal cations is scarce. Since many vital functions depend on the network of interactions occurring in various biofluids, this chapter reviews their complex formation with phosphates, nucleotides, amino acids, and related ligands of biological relevance. Literature data on this topic are quite rare if compared to other cations. Generally, the stability of alkali metal ion complexes of organic and inorganic ligands is rather low (usually log K  Na(+) > K(+) > Rb(+) > Cs(+). For example, for citrate it is: log K ML = 0.88, 0.80, 0.48, 0.38, and 0.13 at 25 °C and infinite dilution. Some considerations are made on the main aspects related to the difficulties in the determination of weak complexes. The importance of the alkali metal ion complexes was also studied in the light of modelling natural fluids and in the use of these cations as probes for different processes. Some empirical relationships are proposed for the dependence of the stability constants of Na(+) complexes on the ligand charge, as well as for correlations among log K values of NaL, KL or LiL species (L = generic ligand).

  17. Serum heavy metals and hemoglobin related compounds in Saudi Arabia firefighters

    Directory of Open Access Journals (Sweden)

    Al-Malki Abdulrahman L

    2009-07-01

    Full Text Available Abstract Background Firefighters are frequently exposed to significant concentrations of hazardous materials including heavy metals, aldehydes, hydrogen chloride, dichlorofluoromethane and some particulates. Many of these materials have been implicated in the triggering of several diseases. The aim of the present study is to investigate the effect of fire smoke exposure on serum heavy metals and possible affection on iron functions compounds (total iron binding capacity, transferrin saturation percent, ferritin, unsaturated iron-binding capacity blood hemoglobin and carboxyhemoglobin,. Subjects and methods Two groups of male firefighter volunteers were included; the first included 28 firefighters from Jeddah city, while the second included 21 firefighters from Yanbu city with an overall age rang of 20–48 years. An additional group of 23 male non-firefighters volunteered from both cities as normal control subjects. Blood samples were collected from all volunteer subjects and investigated for relevant parameters. Results The results obtained showed that there were no statistically significant changes in the levels of serum heavy metals in firefighters as compared to normal control subjects. Blood carboxyhemoglobin and serum ferritin were statistically increased in Jeddah firefighters, (p Conclusion Such results might point to the need for more health protective and prophylactic measures to avoid such hazardous health effects (elevated Blood carboxyhemoglobin and serum ferritin and decreased serum TIBC and UIBC that might endanger firefighters working under dangerous conditions. Firefighters must be under regular medical follow-up through standard timetabled medical laboratory investigations to allow for early detection of any serum biochemical or blood hematological changes.

  18. New synthesis ways of supported metallic catalysts and structure-reactivity relations in catalysis by metals; Nouvelles voies de syntheses de catalyseurs metalliques supportes et relations structure-reactivite en catalyse par les metaux

    Energy Technology Data Exchange (ETDEWEB)

    Uzio, D.

    2006-01-15

    This work deals with some research studies in the field of supported metallic catalysts. In all these works have been studied the characteristics bound to the active sites and the relations between these characteristics and the catalytic performances. The genesis of colloidal suspensions of transition metallic oxide has been used for the preparation of selective hydrogenation catalysts. At first studied in the case of palladium, this new synthesis way has been used for other metals such as Pt, Ni or Co. These studies have then been developed for preparing bimetallic catalysts (PdSn) with as supplementary aim the control of the homogeneity of the bimetallic character at the scale of nano-metric particles. These works have particularly allowed to specify the chemistry of the solutions of some metallic complexes and to rationalize the chemical processes carried out in the usual fabrication processes. Studies on size effects and the study of the reactivity of the nano and sub nano-metric particle have then been developed. Indeed, the clusters containing some atoms can see their intrinsic properties varied very strongly under the influence of several parameters as the number of atoms, the nature of the support, the reactional atmosphere. Using the knowledge acquired during the preceding works (chemistry of palladium aqueous solutions), the study of new methods of preparation of particles containing very few atoms has brought new data on the properties of hyper dispersed particles as well as on the principle of sensitivity to structure. The contribution of the support to the catalytic process for the hydrogenation of different substrates has been studied too. (O.M.)

  19. On the mass-metallicity relation, velocity dispersion and gravitational well depth of GRB host galaxies

    DEFF Research Database (Denmark)

    Arabsalmani, Maryam; Møller, Palle; Fynbo, Johan P. U.

    2015-01-01

    -DLA samples and compare the measured stellar masses for the four hosts where stellar masses have been determined from SED fits. We find excellent agreement and conclude that, on basis of all available data and tests, long duration GRB-DLA hosts and intervening QSO-DLAs are consistent with being drawn from...... away from the metallicity in the centre of the galaxy, second the path of the sightline through different parts of the potential well of the dark matter halo will cause different velocity fields to be sampled. We report evidence suggesting that this second effect may have been detected....

  20. Improvements in or relating to processes for reducing the oxygen content of metal oxides

    International Nuclear Information System (INIS)

    James, R.H.; Spooner, J.A.

    1980-01-01

    A process is described for reducing the oxygen content of a metal oxide material (such as an intimate mixture of uranium and plutonium oxides or a mixed oxide of uranium and plutonium) by contacting the material with a hydrogen-containing gas at an elevated temperature, wherein the material is contained in a plurality of carbon crucibles, each crucible having apertured ends and being otherwise a closed vessel, the crucibles being moved through a heated zone in end-to-end contact and thereby forming a duct through which the gas is passed counter-current to the direction of movement of the crucibles. (author)

  1. Soil-Plant Metal Relations in Panax notoginseng: An Ecosystem Health Risk Assessment

    Science.gov (United States)

    Ou, Xiaohong; Wang, Li; Guo, Lanping; Cui, Xiuming; Liu, Dahui; Yang, Ye

    2016-01-01

    This study features a survey of the content of heavy metals (Pb, Cd, Cr, As, Hg and Cu) in root and cultivation soils of Panax notoginseng (P. notoginseng), carried out in China’s Yunnan Province. The average contents of Pb, Cd, Cr, As, Hg, and Cu in the soil were 61.6, 0.4, 102.4, 57.1, 0.3, and 35.1 mg·kg−1, respectively. The heavy metals’ pollution indexes can be ranked as follows: As > Cd > Hg > Cu > Cr > Pb. The proportion of soil samples at slight, middle, strong, very strong, and extremely strong levels of potential environmental risk had values of 5.41%, 21.62%, 35.14%, 10.81%, and 27.03%, respectively. The potential environment risk index (RI) showed that 29.73% out of the total sample sites were above the level of strong and extremely strong. The ranges of Pb, Cd, Cr, As, Hg, and Cu content in tuber were 0.04–3.26, 0.04–0.33, 0.22–5.4, 0.10–1.8, 0.00–0.02, and 5.0–20.9 mg·kg−1, respectively. In combination with P. notoginseng consumption data, the estimated heavy metal daily intakes (EDIs) were 0.08–0.23, 0.006–0.019, 0.17–0.52, 0.04–0.12, 0.001–0.002, and 0.59–1.77 μg·kg−1·bw/day. All target hazard quotients (THQs) of individual elements and hazard indexes (HI) were less than one. The present study indicates that most of the P. notoginseng cultivation soil in the province of Yunnan presented slight and moderate ecological risk. Thus, more attention should be given to the heavy metals As, Cd, and Hg when selecting planting areas for the cultivation of P. notoginseng. Health risks associated with the intake of a single element or consumption of the combined metals through P. notoginseng are absent. PMID:27827951

  2. Assessment of complex water pollution with heavy metals and Pyrethroid pesticides on transcript levels of metallothionein and immune related genes.

    Science.gov (United States)

    Ghazy, Haneen A; Abdel-Razek, Mohamed A S; El Nahas, Abeer F; Mahmoud, Shawky

    2017-09-01

    Alteration of immunological function of an aquatic organism can be used as an indicator for evaluating the direct effect of exposure to pollutants. The aim of this work is to assess the impact of complex water pollution with special reference to Pyrethroid pesticides and heavy metals on mRNA transcript levels of Metallothionine and some immune related genes of Nile tilapia (Oreochromas Niloticus). Residues of six heavy metals and six Pyrethroid were assessed in water as well as fish tissues at three different sites of Lake Burullus, located at Northern Egypt. Variations of water physicochemical properties associated with different levels of heavy metals at the three different sections were recorded. Tissue residues of Fe, Mn and Zn, Cu, Ni exceed water levels in contrast to elevated water level of Pb. All assessed Pyrethroids are detected in fish tissue samples with higher concentration (3-42 folds) than that found in water samples especially Cypermethrin. Significant down-regulation of expression levels of metallothionein (MT) at the three sections of the lake was observed. The expression of immune related genes (IgM) and inflammatory cytokines (TNF, IL.8 and IL.1) were affected. IgM and TNF were significantly down-regulated at eastern and western section of the lake; meanwhile the expression of IL8 is down regulated at the three sections of the lack. IL1 was significantly up-regulated at eastern and middle sections. We conclude that, variable gene expression of MT and immune-related genes at the three sections of the lack impose different response to complex water pollution in relation to variable aquatic environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Six sigma implementation and its effects on configuration management related to metal industry

    International Nuclear Information System (INIS)

    Tariq, M.M.; Ahmad, S.F.; Mahmoo, A.; Kalsoom, T.

    2006-01-01

    This paper discusses the implementation of Six Sigma and its effects on Configuration Management (CM) of metal industry. The basic idea behind the Six Sigma philosophy is to continuously reduce product and process variation. Design for Six Sigma (DFSS) methodology generates new processes, products, services, plants, etc., whereas Define, Measure, Analyze, Improve and Control (DMAIC) methodology improves existing processes, products, services, designs, plants, etc. The DFSS project stages are summarized as Identify, Design, Optimize, and Validate (IDOV). Role of CM for DFSS and DMAIC will be discussed. Seven steps for Six Sigma introduction in new management strategy and the other seven steps for Six Sigma improvement implementation shall be discussed indicating possible role of CM. Tasks of Black Belt leader in Six Sigma implementation are very important. The expected outcomes of Six Sigma efforts are: Faster and more robust product development. More efficient and capable manufacturing processes and, more confident overall business performance. The investigation and knowledge of Six Sigma effects produced in metals industry on CM will increase the effectiveness of each other, and it will be a better, reliable and well documented approach towards Six Sigma. (author)

  4. Mandibular remodeling measured on cephalograms. 1. Osseous changes relative to superimposition on metallic implants.

    Science.gov (United States)

    Baumrind, S; Ben-Bassat, Y; Korn, E L; Bravo, L A; Curry, S

    1992-08-01

    We report the results of a study aimed at quantifying remodeling of mandibular surfaces in a sample of growing children who represent those usually treated by orthodontists in the mixed and early adult dentition. The sample, 31 patients with metallic implants of the Björk-type, was monitored at annual intervals between 8 1/2 and 15 1/2 years of age. (Maxillary remodeling changes for the sample have been reported earlier.) The present article reports findings concerning changes at condyle, gonion, menton, pogonion, and point B as identified on lateral cephalograms. Data are reported in the Frankfort plane frame of reference with the cephalograms from different time points superimposed on the metallic implants. Mean displacement at condyle was larger than that at any other landmark and was similar in magnitude and direction to the observations of Björk when the difference in orientation of the vertical axis in the two studies is taken into account. The mean displacement of gonion was in an upward and backward direction at an angle of approximately 45 degrees to the Frankfort plane. Mean displacements at menton and pogonion were in a downward and backward direction but were very small. Mean displacement at point B was somewhat greater than that of menton and gonion, oriented in an upward and backward direction. Individual variation for most of the parameters measured was sufficiently large to warrant the inference that caution should be used when mean values are applied to the analysis of individual cases.

  5. Stellar Absorption Line Analysis of Local Star-forming Galaxies: The Relation between Stellar Mass, Metallicity, Dust Attenuation, and Star Formation Rate

    International Nuclear Information System (INIS)

    Jabran Zahid, H.; Kudritzki, Rolf-Peter; Ho, I-Ting; Conroy, Charlie; Andrews, Brett

    2017-01-01

    We analyze the optical continuum of star-forming galaxies in the Sloan Digital Sky Survey by fitting stacked spectra with stellar population synthesis models to investigate the relation between stellar mass, stellar metallicity, dust attenuation, and star formation rate. We fit models calculated with star formation and chemical evolution histories that are derived empirically from multi-epoch observations of the stellar mass–star formation rate and the stellar mass–gas-phase metallicity relations, respectively. We also fit linear combinations of single-burst models with a range of metallicities and ages. Star formation and chemical evolution histories are unconstrained for these models. The stellar mass–stellar metallicity relations obtained from the two methods agree with the relation measured from individual supergiant stars in nearby galaxies. These relations are also consistent with the relation obtained from emission-line analysis of gas-phase metallicity after accounting for systematic offsets in the gas-phase metallicity. We measure dust attenuation of the stellar continuum and show that its dependence on stellar mass and star formation rate is consistent with previously reported results derived from nebular emission lines. However, stellar continuum attenuation is smaller than nebular emission line attenuation. The continuum-to-nebular attenuation ratio depends on stellar mass and is smaller in more massive galaxies. Our consistent analysis of stellar continuum and nebular emission lines paves the way for a comprehensive investigation of stellar metallicities of star-forming and quiescent galaxies.

  6. Stellar Absorption Line Analysis of Local Star-forming Galaxies: The Relation between Stellar Mass, Metallicity, Dust Attenuation, and Star Formation Rate

    Energy Technology Data Exchange (ETDEWEB)

    Jabran Zahid, H. [Smithsonian Astrophysical Observatory, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Kudritzki, Rolf-Peter; Ho, I-Ting [University of Hawaii at Manoa, Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Conroy, Charlie [Department of Astronomy, Harvard University, Cambridge, MA, 02138 (United States); Andrews, Brett, E-mail: zahid@cfa.harvard.edu [PITT PACC, Department of Physics and Astronomy, University of Pittsburgh, 3941 O’Hara Street, Pittsburgh, PA 15260 (United States)

    2017-09-20

    We analyze the optical continuum of star-forming galaxies in the Sloan Digital Sky Survey by fitting stacked spectra with stellar population synthesis models to investigate the relation between stellar mass, stellar metallicity, dust attenuation, and star formation rate. We fit models calculated with star formation and chemical evolution histories that are derived empirically from multi-epoch observations of the stellar mass–star formation rate and the stellar mass–gas-phase metallicity relations, respectively. We also fit linear combinations of single-burst models with a range of metallicities and ages. Star formation and chemical evolution histories are unconstrained for these models. The stellar mass–stellar metallicity relations obtained from the two methods agree with the relation measured from individual supergiant stars in nearby galaxies. These relations are also consistent with the relation obtained from emission-line analysis of gas-phase metallicity after accounting for systematic offsets in the gas-phase metallicity. We measure dust attenuation of the stellar continuum and show that its dependence on stellar mass and star formation rate is consistent with previously reported results derived from nebular emission lines. However, stellar continuum attenuation is smaller than nebular emission line attenuation. The continuum-to-nebular attenuation ratio depends on stellar mass and is smaller in more massive galaxies. Our consistent analysis of stellar continuum and nebular emission lines paves the way for a comprehensive investigation of stellar metallicities of star-forming and quiescent galaxies.

  7. The Effect of Susceptibility Artifacts Related to Metallic Implants on Adjacent-Lesion Assessment in Simultaneous TOF PET/MR.

    Science.gov (United States)

    Svirydenka, Hanna; Delso, Gaspar; De Galiza Barbosa, Felipe; Huellner, Martin; Davison, Helen; Fanti, Stefano; Veit-Haibach, Patrick; Ter Voert, Edwin E G W

    2017-07-01

    Metalic implants may affect attenuation correction (AC) in PET/MR imaging. The purpose of this study was to evaluate the effect of susceptibility artifacts related to metallic implants on adjacent metabolically active lesions in clinical simultaneous PET/MR scanning for both time-of-flight (TOF) and non-TOF reconstructed PET images. Methods: We included 27 patients without implants but with confirmed 18 F-FDG-avid lesions adjacent to common implant locations. In all patients, a clinically indicated whole-body 18 F-FDG PET/MR scan was acquired. Baseline non-TOF and TOF PET images were reconstructed. Reconstruction was repeated after the introduction of artificial signal voids in the AC map to simulate metallic implants in standard anatomic areas. All reconstructed images were qualitatively and quantitatively assessed and compared with the baseline images. Results: In total, 51 lesions were assessed. In 40 and 50 of these cases (non-TOF and TOF, respectively), the detectability of the lesions did not change; in 9 and 1 cases, the detectability changed; and in 2 non-TOF cases, the lesions were no longer visible after the introduction of metallic artifacts. The inclusion of TOF information significantly reduced artifacts due to simulated implants in the femoral head, sternum, and spine ( P = 0.01, 0.01, and 0.03, respectively). It also improved image quality in these locations ( P = 0.02, 0.01, and 0.01, respectively). The mean percentage error was -3.5% for TOF and -4.8% for non-TOF reconstructions, meaning that the inclusion of TOF information reduced the percentage error in SUV max by 28.5% ( P metallic implants have a significant effect on small, moderately 18 F-FDG-avid lesions near the implant site that possibly may go unnoticed without TOF information. On larger, highly 18 F-FDG-avid lesions, the metallic implants had only a limited effect. The largest significant quantitative difference was found in artifacts of the sternum. There was only a weak inverse

  8. THE QUEST FOR CRADLES OF LIFE: USING THE FUNDAMENTAL METALLICITY RELATION TO HUNT FOR THE MOST HABITABLE TYPE OF GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Dayal, Pratika [Institute for Computational Cosmology, Department of Physics, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Cockell, Charles [UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3HJ (United Kingdom); Rice, Ken [Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ (United Kingdom); Mazumdar, Anupam [Consortium for Fundamental Physics, Lancaster University, Lancaster LA1 4 YB (United Kingdom)

    2015-09-01

    The field of astrobiology has made huge strides in understanding the habitable zones around stars (stellar habitable zones) where life can begin, sustain its existence and evolve into complex forms. A few studies have extended this idea by modeling galactic-scale habitable zones (galactic habitable zones) for our Milky Way (MW) and specific elliptical galaxies. However, estimating the habitability for galaxies spanning a wide range of physical properties has so far remained an outstanding issue. Here, we present a “cosmobiological” framework that allows us to sift through the entire galaxy population in the local universe and answer the question, “Which type of galaxy is most likely to host complex life in the cosmos?” Interestingly, the three key astrophysical criteria governing habitability (total mass in stars, total metal mass and ongoing star formation rate) are found to be intricately linked through the “fundamental metallicity relation” as shown by Sloan Digital Sky Survey observations of more than a hundred thousand galaxies in the local universe. Using this relation we show that metal-rich, shapeless giant elliptical galaxies at least twice as massive as the MW (with a tenth of its star formation rate) can potentially host ten thousand times as many habitable (Earth-like) planets, making them the most probable “cradles of life” in the universe.

  9. THE QUEST FOR CRADLES OF LIFE: USING THE FUNDAMENTAL METALLICITY RELATION TO HUNT FOR THE MOST HABITABLE TYPE OF GALAXY

    International Nuclear Information System (INIS)

    Dayal, Pratika; Cockell, Charles; Rice, Ken; Mazumdar, Anupam

    2015-01-01

    The field of astrobiology has made huge strides in understanding the habitable zones around stars (stellar habitable zones) where life can begin, sustain its existence and evolve into complex forms. A few studies have extended this idea by modeling galactic-scale habitable zones (galactic habitable zones) for our Milky Way (MW) and specific elliptical galaxies. However, estimating the habitability for galaxies spanning a wide range of physical properties has so far remained an outstanding issue. Here, we present a “cosmobiological” framework that allows us to sift through the entire galaxy population in the local universe and answer the question, “Which type of galaxy is most likely to host complex life in the cosmos?” Interestingly, the three key astrophysical criteria governing habitability (total mass in stars, total metal mass and ongoing star formation rate) are found to be intricately linked through the “fundamental metallicity relation” as shown by Sloan Digital Sky Survey observations of more than a hundred thousand galaxies in the local universe. Using this relation we show that metal-rich, shapeless giant elliptical galaxies at least twice as massive as the MW (with a tenth of its star formation rate) can potentially host ten thousand times as many habitable (Earth-like) planets, making them the most probable “cradles of life” in the universe

  10. Mobilisation of heavy metals into the urine by CaEDTA: relation to erythrocyte and plasma concentrations and exposure indicators.

    Science.gov (United States)

    Araki, S; Aono, H; Murata, K

    1986-09-01

    To investigate the effects of calcium disodium ethylenediamine tetra-acetate (CaEDTA) on the urinary excretion, erythrocyte, and plasma concentrations and exposure indicators of seven heavy metals, CaEDTA was administered by intravenous infusion to 20 workers exposed to lead, zinc, and copper. The workers' blood lead concentrations ranged from 22 to 59 micrograms/dl (mean 38 micrograms/dl (1.8 mumol/l]. The 24 hour urinary excretion of metals after CaEDTA administration (mobilisation yield) was on average 13 times the background excretion for lead, 11 times for zinc, 3.8 times for manganese, 3.4 times for cadmium, 1.3 times for copper, and 1.1 times for chromium; no significant increase was found for mercury. The mobilisation yield of lead (MPb) was significantly correlated with whole blood and erythrocyte concentrations and the urinary excretion of lead but not with its plasma concentration; similarly, the mobilisation yield of cadmium was significantly correlated with its erythrocyte concentration. In addition, MPb was significantly correlated with intra-erythrocytic enzyme delta-aminolaevulinic acid dehydratase activity and urinary coproporphyrin excretion. The relation between the mobilisation yield of heavy metals and their body burden (and toxic signs) is discussed in the light of these findings.

  11. Assessment of heavy metal accumulation in two species of Tillandsia in relation to atmospheric emission sources in Argentina

    International Nuclear Information System (INIS)

    Wannaz, Eduardo D.; Carreras, Hebe A.; Perez, Carlos A.; Pignata, Maria L.

    2006-01-01

    The ability of Tillandsia capillaris Ruiz and Pav. f. capillaris and Tillandsia permutata A. Cast. to accumulate heavy metals was evaluated in relation to potential atmospheric emission sources in Argentina. The sampling areas (n = 38) were chosen in the province of Cordoba, located in the center of Argentina, and categorized according to land use, anthropogenic activities and/or distance to potential heavy metal emission sources. In each sampling site, pools of 40-50 individuals of each species were made from plants collected along the four cardinal directions. The concentrations of V, Mn, Fe, Co, Ni, Cu, Zn, Pb and Br of these samples were measured by Total Reflection X-Ray Fluorescence (TXRF) analysis with Synchrotron Radiation. Each species was submitted to a cluster analysis in order to discriminate different groups of heavy metals as tracers of natural or anthropogenic sources. A Contamination Factor (CF) was calculated using the concentrations of the elements in each sample compared to their concentrations in the control samples. Finally, the rank coefficients of correlation between the CFs and the categorical variables characteristic of each site (land use and anthropogenic load) were analyzed. A positive correlation was found for T. capillaris between the CFs of V, Mn, Co, Ni, Cu and Zn and the urban-industrial category, whereas the CF values for Zn and Pb were positively correlated with the road category. In T. permutata there was a positive correlation between the CF of Zn and the urban-industrial category and the CF of Pb with the road category. We therefore conclude that T. capillaris is a more efficient metal accumulator in passive biomonitoring studies

  12. Assessment of heavy metal accumulation in two species of Tillandsia in relation to atmospheric emission sources in Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Wannaz, Eduardo D. [Departamento de Quimica, Instituto Multidisciplinario de Biologia Vegetal - IMBIV/CONICET-UNC, Facultad de Ciencias Exactas, Fisicas y Naturales, Universidad Nacional de Cordoba, Av. Velez Sarsfield 1611, Ciudad Universitaria (X5016GCA) Cordoba (Argentina); Carreras, Hebe A. [Departamento de Quimica, Instituto Multidisciplinario de Biologia Vegetal - IMBIV/CONICET-UNC, Facultad de Ciencias Exactas, Fisicas y Naturales, Universidad Nacional de Cordoba, Av. Velez Sarsfield 1611, Ciudad Universitaria (X5016GCA) Cordoba (Argentina); Perez, Carlos A. [Laboratorio Nacional de Luz Sincrotron - LNLS/CNPq, Caixa Postal 6192, 13038-970 Campinas (Brazil); Pignata, Maria L. [Departamento de Quimica, Instituto Multidisciplinario de Biologia Vegetal - IMBIV/CONICET-UNC, Facultad de Ciencias Exactas, Fisicas y Naturales, Universidad Nacional de Cordoba, Av. Velez Sarsfield 1611, Ciudad Universitaria (X5016GCA) Cordoba (Argentina)]. E-mail: pignata@com.uncor.edu

    2006-05-15

    The ability of Tillandsia capillaris Ruiz and Pav. f. capillaris and Tillandsia permutata A. Cast. to accumulate heavy metals was evaluated in relation to potential atmospheric emission sources in Argentina. The sampling areas (n = 38) were chosen in the province of Cordoba, located in the center of Argentina, and categorized according to land use, anthropogenic activities and/or distance to potential heavy metal emission sources. In each sampling site, pools of 40-50 individuals of each species were made from plants collected along the four cardinal directions. The concentrations of V, Mn, Fe, Co, Ni, Cu, Zn, Pb and Br of these samples were measured by Total Reflection X-Ray Fluorescence (TXRF) analysis with Synchrotron Radiation. Each species was submitted to a cluster analysis in order to discriminate different groups of heavy metals as tracers of natural or anthropogenic sources. A Contamination Factor (CF) was calculated using the concentrations of the elements in each sample compared to their concentrations in the control samples. Finally, the rank coefficients of correlation between the CFs and the categorical variables characteristic of each site (land use and anthropogenic load) were analyzed. A positive correlation was found for T. capillaris between the CFs of V, Mn, Co, Ni, Cu and Zn and the urban-industrial category, whereas the CF values for Zn and Pb were positively correlated with the road category. In T. permutata there was a positive correlation between the CF of Zn and the urban-industrial category and the CF of Pb with the road category. We therefore conclude that T. capillaris is a more efficient metal accumulator in passive biomonitoring studies.

  13. Indoor metallic pollution related to mining activity in the Bolivian Altiplano.

    Science.gov (United States)

    Fontúrbel, Francisco E; Barbieri, Enio; Herbas, Cristian; Barbieri, Flavia L; Gardon, Jacques

    2011-10-01

    The environmental pollution associated with mining and metallurgical activities reaches its greatest extent in several Andean cities and villages. Many locations in this area have accumulated through centuries a large amount of mining wastes, often disregarding the magnitude of this situation. However, in these naturally mineralized regions, there is little information available stating the exact role of mining and metallurgical industries in urban pollution. In this study, we demonstrated that the various metallic elements present in indoor dust (As, Cd, Cu, Pb, Sb, Sn, Zn) had a common origin and this contamination was increased by the proximity to the mines. Lead dust concentration was found at concerning levels for public health. In addition, wrong behaviors such as carrying mining workwear home contributed to this indoor dust pollution. Consequently, the constant exposure of the population could represent a potential health hazard for vulnerable groups, especially children. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Metal-Binding Ability of Leu-Enkephalin, Related Glycoconjugates and Peptidomimetics

    Directory of Open Access Journals (Sweden)

    Zsuzsa Majer

    2015-12-01

    Full Text Available Both the chemistry and consequences of the nonenzymatic reaction between reducing sugars and reactive amino groups of amino acids, peptides and proteins (known as the Maillard reaction, have received considerable attention in food and health science fields. This initial reaction results in Amadori and similar products formation, followed by degradation to advanced glycation end products (AGEs. It is well established that AGEs are associated with color and odor of thermally processed or stored food, as well as with pathogen products in a number of diseases. The model systems of early stage Maillard reaction products (MRP were prepared between endogenous opioid peptide leucine enkephalin (1 and D-glucose / D-glucuronic acid. The complexation ability of prepared MRP with metal ions (Ca2+, Zn2+, Al3+, Pb2+ and Cu2+ was investigated and compared to the complexation ability of parent peptide using ECD and FTIR spectroscopic measurements.

  15. THE GAS PHASE MASS METALLICITY RELATION FOR DWARF GALAXIES: DEPENDENCE ON STAR FORMATION RATE AND HI GAS MASS

    Energy Technology Data Exchange (ETDEWEB)

    Jimmy; Tran, Kim-Vy [George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Saintonge, Amélie; Accurso, Gioacchino [Department of Physics and Astronomy, University College London, Gower Place, London WC1E 6BT (United Kingdom); Brough, Sarah; Oliva-Altamirano, Paola [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia)

    2015-10-20

    Using a sample of dwarf galaxies observed using the VIMOS IFU on the Very Large Telescope, we investigate the mass–metallicity relation (MZR) as a function of star formation rate (FMR{sub SFR}) as well as HI-gas mass (FMR{sub HI}). We combine our IFU data with a subsample of galaxies from the ALFALFA HI survey crossmatched to the Sloan Digital Sky Survey (SDSS) to study the FMR{sub SFR} and FMR{sub HI} across the stellar mass range 10{sup 6.6}–10{sup 8.8} M{sub ⊙}, with metallicities as low as 12 + log(O/H) = 7.67. We find the 1σ mean scatter in the MZR to be 0.05 dex. The 1σ mean scatter in the FMR{sub SFR} (0.02 dex) is significantly lower than that of the MZR. The FMR{sub SFR} is not consistent between the IFU observed galaxies and the ALFALFA/SDSS galaxies for SFRs lower than 10{sup −2.4} M{sub ⊙} yr{sup −1}, however, this could be the result of limitations of our measurements in that regime. The lowest mean scatter (0.01 dex) is found in the FMR{sub HI}. We also find that the FMR{sub HI} is consistent between the IFU observed dwarf galaxies and the ALFALFA/SDSS crossmatched sample. We introduce the fundamental metallicity luminosity counterpart to the FMR, again characterized in terms of SFR (FML{sub SFR}) and HI-gas mass (FML{sub HI}). We find that the FML{sub HI} relation is consistent between the IFU observed dwarf galaxy sample and the larger ALFALFA/SDSS sample. However, the 1σ scatter for the FML{sub HI} relation is not improved over the FMR{sub HI} scenario. This leads us to conclude that the FMR{sub HI} is the best candidate for a physically motivated fundamental metallicity relation.

  16. EVOLUTION OF THE MASS-METALLICITY RELATIONS IN PASSIVE AND STAR-FORMING GALAXIES FROM SPH-COSMOLOGICAL SIMULATIONS

    International Nuclear Information System (INIS)

    Romeo Velonà, A. D.; Gavignaud, I.; Meza, A.; Sommer-Larsen, J.; Napolitano, N. R.; Antonuccio-Delogu, V.; Cielo, S.

    2013-01-01

    We present results from SPH-cosmological simulations, including self-consistent modeling of supernova feedback and chemical evolution, of galaxies belonging to two clusters and 12 groups. We reproduce the mass-metallicity (ZM) relation of galaxies classified in two samples according to their star-forming (SF) activity, as parameterized by their specific star formation rate (sSFR), across a redshift range up to z = 2. The overall ZM relation for the composite population evolves according to a redshift-dependent quadratic functional form that is consistent with other empirical estimates, provided that the highest mass bin of the brightest central galaxies is excluded. Its slope shows irrelevant evolution in the passive sample, being steeper in groups than in clusters. However, the subsample of high-mass passive galaxies only is characterized by a steep increase of the slope with redshift, from which it can be inferred that the bulk of the slope evolution of the ZM relation is driven by the more massive passive objects. The scatter of the passive sample is dominated by low-mass galaxies at all redshifts and keeps constant over cosmic times. The mean metallicity is highest in cluster cores and lowest in normal groups, following the same environmental sequence as that previously found in the red sequence building. The ZM relation for the SF sample reveals an increasing scatter with redshift, indicating that it is still being built at early epochs. The SF galaxies make up a tight sequence in the SFR-M * plane at high redshift, whose scatter increases with time alongside the consolidation of the passive sequence. We also confirm the anti-correlation between sSFR and stellar mass, pointing at a key role of the former in determining the galaxy downsizing, as the most significant means of diagnostics of the star formation efficiency. Likewise, an anti-correlation between sSFR and metallicity can be established for the SF galaxies, while on the contrary more active galaxies

  17. Spectral Analysis Related to Bare-Metal and Drug-Eluting Coronary Stent Implantation

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Rose Mary Ferreira Lisboa da, E-mail: roselisboa@cardiol.br [Faculdade de Medicina da UFMG, Divinópolis, MG (Brazil); Silva, Carlos Augusto Bueno [Faculdade de Medicina da UFMG, Divinópolis, MG (Brazil); Belo Horizonte, Hospital São João de Deus, Divinópolis, MG (Brazil); Greco, Otaviano José [Belo Horizonte, Hospital São João de Deus, Divinópolis, MG (Brazil); Moreira, Maria da Consolação Vieira [Faculdade de Medicina da UFMG, Divinópolis, MG (Brazil)

    2014-08-15

    The autonomic nervous system plays a central role in cardiovascular regulation; sympathetic activation occurs during myocardial ischemia. To assess the spectral analysis of heart rate variability during stent implantation, comparing the types of stent. This study assessed 61 patients (mean age, 64.0 years; 35 men) with ischemic heart disease and indication for stenting. Stent implantation was performed under Holter monitoring to record the spectral analysis of heart rate variability (Fourier transform), measuring the low-frequency (LF) and high-frequency (HF) components, and the LF/HF ratio before and during the procedure. Bare-metal stent was implanted in 34 patients, while the others received drug-eluting stents. The right coronary artery was approached in 21 patients, the left anterior descending, in 28, and the circumflex, in 9. As compared with the pre-stenting period, all patients showed an increase in LF and HF during stent implantation (658 versus 185 ms2, p = 0.00; 322 versus 121, p = 0.00, respectively), with no change in LF/HF. During stent implantation, LF was 864 ms2 in patients with bare-metal stents, and 398 ms2 in those with drug-eluting stents (p = 0.00). The spectral analysis of heart rate variability showed no association with diabetes mellitus, family history, clinical presentation, beta-blockers, age, and vessel or its segment. Stent implantation resulted in concomitant sympathetic and vagal activations. Diabetes mellitus, use of beta-blockers, and the vessel approached showed no influence on the spectral analysis of heart rate variability. Sympathetic activation was lower during the implantation of drug-eluting stents.

  18. BEP-relations for N2 dissociation over stepped transition metal and alloy surfaces

    DEFF Research Database (Denmark)

    Fronczek-Munter, Ture Rønved; Bligaard, Thomas; Christensen, Claus H.

    2008-01-01

    , a perfectly linear Bronsted-Evans-Polanyi (BEP) relation between the transition-state potential energy and the dissociative chemisorption energy is obtained. The perfect BEP relation, which extends over 12 eV in chemisorption energy, suggests that the manifestation of BEP relations for surface reactions...... is a general electronic structure effect, and that geometric effects are responsible for the scatter which is normally observed around the BEP line. The BEP relation is also shown to be valid for both surface and bulk alloys. The scatter is, however, larger than for the pure elements. This can be understood...

  19. Molecular diversity of arbuscular mycorrhizal fungi in relation to soil chemical properties and heavy metal contamination

    International Nuclear Information System (INIS)

    Zarei, Mehdi; Hempel, Stefan; Wubet, Tesfaye; Schaefer, Tina; Savaghebi, Gholamreza; Jouzani, Gholamreza Salehi; Nekouei, Mojtaba Khayam; Buscot, Francois

    2010-01-01

    Abundance and diversity of arbuscular mycorrhizal fungi (AMF) associated with dominant plant species were studied along a transect from highly lead (Pb) and zinc (Zn) polluted to non-polluted soil at the Anguran open pit mine in Iran. Using an established primer set for AMF in the internal transcribed spacer (ITS) region of rDNA, nine different AMF sequence types were distinguished after phylogenetic analyses, showing remarkable differences in their distribution patterns along the transect. With decreasing Pb and Zn concentration, the number of AMF sequence types increased, however one sequence type was only found in the highly contaminated area. Multivariate statistical analysis revealed that further factors than HM soil concentration affect the AMF community at contaminated sites. Specifically, the soils' calcium carbonate equivalent and available P proved to be of importance, which illustrates that field studies on AMF distribution should also consider important environmental factors and their possible interactions. - The molecular diversity of AMF was found to be influenced by a combination of soil heavy metal and other soil chemical parameters.

  20. Molecular diversity of arbuscular mycorrhizal fungi in relation to soil chemical properties and heavy metal contamination

    Energy Technology Data Exchange (ETDEWEB)

    Zarei, Mehdi [Department of Soil Science, College of Agriculture, University of Shiraz, Shiraz (Iran, Islamic Republic of); Hempel, Stefan, E-mail: hempel.stefan@googlemail.co [UFZ Helmholtz Centre for Environmental Research Leipzig-Halle, Department of Soil Ecology, Theodor-Lieser-Strasse 4, 06120 Halle (Germany); Freie Universitaet Berlin, Institut fuer Biologie, Okologie der Pflanzen, Altensteinstrasse 6, 14195 Berlin (Germany); Wubet, Tesfaye; Schaefer, Tina [UFZ Helmholtz Centre for Environmental Research Leipzig-Halle, Department of Soil Ecology, Theodor-Lieser-Strasse 4, 06120 Halle (Germany); Savaghebi, Gholamreza [Department of Soil Science Engineering, University College of Agriculture and Natural Resources, University of Tehran, Karaj (Iran, Islamic Republic of); Jouzani, Gholamreza Salehi; Nekouei, Mojtaba Khayam [Agricultural Biotechnology Research Institute of Iran (ABRII), P.O. Box 31535-1897, Karaj (Iran, Islamic Republic of); Buscot, Francois [UFZ Helmholtz Centre for Environmental Research Leipzig-Halle, Department of Soil Ecology, Theodor-Lieser-Strasse 4, 06120 Halle (Germany)

    2010-08-15

    Abundance and diversity of arbuscular mycorrhizal fungi (AMF) associated with dominant plant species were studied along a transect from highly lead (Pb) and zinc (Zn) polluted to non-polluted soil at the Anguran open pit mine in Iran. Using an established primer set for AMF in the internal transcribed spacer (ITS) region of rDNA, nine different AMF sequence types were distinguished after phylogenetic analyses, showing remarkable differences in their distribution patterns along the transect. With decreasing Pb and Zn concentration, the number of AMF sequence types increased, however one sequence type was only found in the highly contaminated area. Multivariate statistical analysis revealed that further factors than HM soil concentration affect the AMF community at contaminated sites. Specifically, the soils' calcium carbonate equivalent and available P proved to be of importance, which illustrates that field studies on AMF distribution should also consider important environmental factors and their possible interactions. - The molecular diversity of AMF was found to be influenced by a combination of soil heavy metal and other soil chemical parameters.

  1. The Simple Metals and New Models of the Interacting-Electron-Gas Type: I. Anomalous Plasmon Dispersion Relations in Heavy Alkali Metals

    Science.gov (United States)

    Okuda, Takashi; Horio, Kohji; Ohmura, Yoshihiro; Mizuno, Yukio

    2018-06-01

    The well-known interacting-electron-gas model of metallic states is modified by replacing the Coulomb interaction by a truncated one to weaken the repulsive force between electrons at short distances. The new model is applied to the so-called simple metals and is found far superior to the old one. Most of the calculations are carried out successfully on the basis of the random-phase-approximation (RPA), which is known much too poor for the old familiar model. In the present paper the numerical value of the new parameter peculiar to the new model is determined systematically with the help of the observed plasmon spectrum for each metal.

  2. Conformational locking by design: relating strain energy with luminescence and stability in rigid metal-organic frameworks.

    Science.gov (United States)

    Shustova, Natalia B; Cozzolino, Anthony F; Dincă, Mircea

    2012-12-05

    Minimization of the torsional barrier for phenyl ring flipping in a metal-organic framework (MOF) based on the new ethynyl-extended octacarboxylate ligand H(8)TDPEPE leads to a fluorescent material with a near-dark state. Immobilization of the ligand in the rigid structure also unexpectedly causes significant strain. We used DFT calculations to estimate the ligand strain energies in our and all other topologically related materials and correlated these with empirical structural descriptors to derive general rules for trapping molecules in high-energy conformations within MOFs. These studies portend possible applications of MOFs for studying fundamental concepts related to conformational locking and its effects on molecular reactivity and chromophore photophysics.

  3. The Sounds of Metal

    DEFF Research Database (Denmark)

    Grund, Cynthia M.

    2015-01-01

    Two, I propose that this framework allows for at least a theoretical distinction between the way in which extreme metal – e.g. black metal, doom metal, funeral doom metal, death metalrelates to its sound as music and the way in which much other music may be conceived of as being constituted...

  4. In situ and laboratory bioassays with Chironomus riparius larvae to assess toxicity of metal contamination in rivers: the relative toxic effect of sediment versus water contamination.

    Science.gov (United States)

    Faria, Mafalda S; Lopes, Ricardo J; Nogueira, António J A; Soares, Amadeu M V M

    2007-09-01

    We used bioassays employing head capsule width and body length increase of Chironomus riparius larvae as end points to evaluate metal contamination in streams. Bioassays were performed in situ near an abandoned Portuguese goldmine in the spring of 2003 and 2004. Bioassays also were performed under laboratory conditions with water and sediment collected from each stream to verify if laboratory bioassays could detect in situ toxicity and to evaluate the relative contribution of sediment and water to overall toxicity. We used field sediments with control water and control sediments with field water to discriminate between metal contamination in water and sediment. Field water with dry and sieved, organic matter-free, and nontreated sediments was used to determine the toxicity of heavy metals that enter the organism through ingested material. In both in situ and laboratory bioassays, body length increase was significantly inhibited by metal contamination, whereas head capsule width was not affected. Body length increase was more affected by contaminated sediment compared to contaminated water. The lowest-effect level of heavy metals was observed in the dry and sieved sediment that prevented ingestion of sediment particles by larvae. These results suggest that body length increase of C. riparius larvae can be used to indicate the impact of metal contamination in rivers. Chironomus riparius larvae are more affected by heavy metals that enter the organism through ingested sediment than by heavy metals dissolved in the water column. Nevertheless, several factors, such as the particle size and organic matter of sediment, must be taken into account.

  5. Plant-associated bacteria and their role in the success or failure of metal phytoextraction projects: first observations of a field-related experiment

    Science.gov (United States)

    Weyens, Nele; Beckers, Bram; Schellingen, Kerim; Ceulemans, Reinhart; Croes, Sarah; Janssen, Jolien; Haenen, Stefan; Witters, Nele; Vangronsveld, Jaco

    2013-01-01

    Phytoextraction has been reported as an economically and ecologically sound alternative for the remediation of metal-contaminated soils. Willow is a metal phytoextractor of interest because it allows to combine a gradual contaminant removal with production of biomass that can be valorized in different ways. In this work two willow clones growing on a metal-contaminated site were selected: ‘Belgisch Rood’ (BR) with a moderate metal extraction capacity and ‘Tora’ (TO) with a twice as high metal accumulation. All cultivable bacteria associated with both willow clones were isolated and identified using 16SrDNA ARDRA analysis followed by 16SrDNA sequencing. Further all isolated bacteria were investigated for characteristics that might promote plant growth (production of siderophores, organic acids and indol acetic acid) and for their metal resistance. The genotypic and phenotypic characterization of the isolated bacteria showed that the TO endophytic bacterial population is more diverse and contains a higher percentage of metal-resistant plant growth promoting bacteria than the endophytic population associated with BR. We hypothesize that the difference in the metal accumulation capacity between BR and TO clones might be at least partly related to differences in characteristics of their associated bacterial population. PMID:23425076

  6. Heavy metals screening of rice bran oils and its relation to composition

    Science.gov (United States)

    Rice bran oil contains beneficial compounds that contribute to the high stability of the oil itself, as well as the health of consumers. As a result, rice bran oil has been growing in popularity and is now widely used in many countries. However, concerns have surfaced in recent years related to the ...

  7. Determination of the Relative Atomic Masses of Metals by Liberation of Molecular Hydrogen

    Science.gov (United States)

    Waghorne, W. Earle; Rous, Andrew J.

    2009-01-01

    Students determine the relative atomic masses of calcium, magnesium, and aluminum by reaction with hydrochloric acid and measurement of the volume of hydrogen gas liberated. The experiment demonstrates stoichiometry and illustrates clearly that mass of the reagent is not the determinant of the amounts in chemical reactions. The experiment is…

  8. Heavy Metal in Children's Tooth Enamel: Related to Autism and Disruptive Behaviors?

    Science.gov (United States)

    Abdullah, Maryam M.; Ly, Agnes R.; Goldberg, Wendy A.; Clarke-Stewart, K. Alison; Dudgeon, John V.; Mull, Christopher G.; Chan, Tony J.; Kent, Erin E.; Mason, Andrew Z.; Ericson, Jonathon E.

    2012-01-01

    To examine possible links between neurotoxicant exposure and neuropsychological disorders and child behavior, relative concentrations of lead, mercury, and manganese were examined in prenatal and postnatal enamel regions of deciduous teeth from children with Autism Spectrum Disorders (ASDs), high levels of disruptive behavior (HDB), and typically…

  9. Relative importance of different exposure routes of heavy metals for humans living near a municipal solid waste incinerator

    International Nuclear Information System (INIS)

    Li, Tong; Wan, Yi; Ben, Yujie; Fan, Senrong; Hu, Jianying

    2017-01-01

    The potential health effects of toxic chemicals (e.g. heavy metals) emitted by municipal solid waste incinerators (MSWIs) are of great concern to local residents, however there have been few studies on the contributions of different exposure pathways and their subsequent effects on the body burden of residents living near MSWIs. In this study, multiple exposure routes of heavy metals including Pb, Cr, Cd and Mn were assessed by investigating the metals in foods (such as vegetables, crops, meats and fruits etc.), drinking water, ambient air and soil collected surrounding an MSWI in Shenzhen, south China. Vegetable ingestion played the most important role in the total average daily dose of Pb and Cr, and cereals were the key exposure routes for Mn and Cd. Compound-specific contaminations were observed in the investigated areas, with Pb and Cr present in the surrounding environment, having accumulated to relatively high levels in the local vegetables, and the intake of contaminated vegetable foods greatly influencing the body burden of Pb and Cr. Consistently, significantly high blood concentrations of Pb and Cr were detected in the local residents compared to a referenced population, and a lack of significant differences was found for Cd and Mn. The results possibly suggested that emission of MSWI influenced the external exposure doses of the major pathways of Pb and Cr in this study, and resulted in the different body burden of metals in humans living near a MSWI. MSWI-local food-humans is an important exposure pathway for residents living near MSWI, and thus should not be neglected in developing future strategies and policies to prevent the high risks suffered by residents living near MSWIs. - Highlights: • Vegetable and cereal ingestion were the main contributors to exposure of Pb/Cr and Mn/Cd, respectively. • Concentrations of Pb/Cr in vegetables grown near MSWI were significantly higher. • Blood concentrations of Pb/Cr in populations near MSWI were

  10. Group 4 Metalloporphyrin diolato Complexes and Catalytic Application of Metalloporphyrins and Related Transition Metal Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Du, Guodong [Iowa State Univ., Ames, IA (United States)

    2003-01-01

    -, bis-alkoxo, and chelating diolato complexes, depending on the identity of diols and the stoichiometry employed. It was also found that tin porphyrin complexes promoted the oxidative cleavage of vicinal diols and the oxidation of α-ketols to α-diketones with dioxygen. In extending the chemistry of metalloporphyrins and analogous complexes, a series of chiral tetraaza macrocyclic ligands and metal complexes were designed and synthesized. Examination of iron(II) complexes showed that they were efficient catalysts for the cyclopropanation of styrene by diazo reagents. Good yields and high diastereoselectivity were obtained with modest enantioselectivity. A rationalization of the stereoselectivity was presented on the basis of structural factors in a carbene intermediate.

  11. Bioaccumulation of heavy metals in the earthworms Lumbricus rubellus and Aporrectodea caliginosa in relation to total and available metal concentrations in field soils

    International Nuclear Information System (INIS)

    Hobbelen, P.H.F.; Koolhaas, J.E.; Gestel, C.A.M. van

    2006-01-01

    The aim of this study was to determine important metal pools for bioaccumulation by the earthworms Lumbricus rubellus and Aporrectodea caliginosa in soils with high binding capacity. Cd, Cu and Zn concentrations in soil, pore water and CaCl 2 extracts of soil, in leaves of the plant species Urtica dioica and in earthworms were determined at 15 field sites constituting a gradient in metal pollution. Variations in the Cu and Cd concentrations in L. rubellus and Cu concentrations in A. caliginosa were best explained by total soil concentrations, while variation in Cd concentration in A. caliginosa was best explained by pore water concentrations. Zn concentrations in L. rubellus and A. caliginosa were not significantly correlated to any determined variable. It is concluded that despite low availability, earthworms in floodplain soils contain elevated concentrations of Cu and Cd, suggesting that uptake takes place not only from the soluble metal concentrations. - Earthworms in floodplain soils not only accumulate heavy metals from soluble metal pools

  12. Bioaccumulation of heavy metals in the earthworms Lumbricus rubellus and Aporrectodea caliginosa in relation to total and available metal concentrations in field soils

    Energy Technology Data Exchange (ETDEWEB)

    Hobbelen, P.H.F. [Department of Animal Ecology, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands)]. E-mail: phobbelen@usgs.gov; Koolhaas, J.E. [Department of Animal Ecology, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands); Gestel, C.A.M. van [Department of Animal Ecology, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands)

    2006-11-15

    The aim of this study was to determine important metal pools for bioaccumulation by the earthworms Lumbricus rubellus and Aporrectodea caliginosa in soils with high binding capacity. Cd, Cu and Zn concentrations in soil, pore water and CaCl{sub 2} extracts of soil, in leaves of the plant species Urtica dioica and in earthworms were determined at 15 field sites constituting a gradient in metal pollution. Variations in the Cu and Cd concentrations in L. rubellus and Cu concentrations in A. caliginosa were best explained by total soil concentrations, while variation in Cd concentration in A. caliginosa was best explained by pore water concentrations. Zn concentrations in L. rubellus and A. caliginosa were not significantly correlated to any determined variable. It is concluded that despite low availability, earthworms in floodplain soils contain elevated concentrations of Cu and Cd, suggesting that uptake takes place not only from the soluble metal concentrations. - Earthworms in floodplain soils not only accumulate heavy metals from soluble metal pools.

  13. Metal-rich fluid inclusions provide new insights into unconformity-related U deposits (Athabasca Basin and Basement, Canada)

    Science.gov (United States)

    Richard, Antonin; Cathelineau, Michel; Boiron, Marie-Christine; Mercadier, Julien; Banks, David A.; Cuney, Michel

    2016-02-01

    -rich alteration. Finally, the metal concentrations in the NaCl-rich and CaCl2-rich brines are among the highest recorded compared to present-day sedimentary formation waters and fluid inclusions from basin-hosted base metal deposits (up to 600 ppm U, 3000 ppm Mn, 4000 ppm Zn, 6000 ppm Cu, 8000 ppm Pb, and 10,000 ppm Fe). The CaCl2-rich brine carries up to one order of magnitude more metal than the NaCl-rich brine. Though the exact origin of major cations and metals of the two brines remains uncertain, their contrasting compositions indicate that the two brines had distinct flow paths and fluid-rock interactions. Large-scale circulation of the brines in the Athabasca Basin and Basement was therefore a key parameter for metal mobility (including U) and formation of unconformity-related U deposits.

  14. Noble metal catalyzed aqueous phase hydrogenation and hydrodeoxygenation of lignin-derived pyrolysis oil and related model compounds.

    Science.gov (United States)

    Mu, Wei; Ben, Haoxi; Du, Xiaotang; Zhang, Xiaodan; Hu, Fan; Liu, Wei; Ragauskas, Arthur J; Deng, Yulin

    2014-12-01

    Aqueous phase hydrodeoxygenation of lignin pyrolysis oil and related model compounds were investigated using four noble metals supported on activated carbon. The hydrodeoxygenation of guaiacol has three major reaction pathways and the demethylation reaction, mainly catalyzed by Pd, Pt and Rh, produces catechol as the products. The presence of catechol and guaiacol in the reaction is responsible for the coke formation and the catalysts deactivation. As expected, there was a significant decrease in the specific surface area of Pd, Pt and Rh catalysts during the catalytic reaction because of the coke deposition. In contrast, no catechol was produced from guaiacol when Ru was used so a completely hydrogenation was accomplished. The lignin pyrolysis oil upgrading with Pt and Ru catalysts further validated the reaction mechanism deduced from model compounds. Fully hydrogenated bio-oil was produced with Ru catalyst. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Fabrication and metallization of 3D electrospun nanofiberous architecture with gold and silver coating for applications related to electrochemical supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Park, Keon Young [University of Pennsylvania, 3451 Walnut Street, Philadelphia, PA 19104 (United States); Ramaraj, B. [Research and Development Department, Central Institute of Plastics Engineering and Technology (CIPET), 630, Phase IV, GIDC, Vatva, Ahmedabad 382445 (India); Choi, Won Suk [Department of Chemistry, Hannam University, 461-6 Jeon min-dong, Yuseoung-gu, Daejeon 305-811 (Korea, Republic of); Yoon, Kuk Ro, E-mail: kryoon@hannam.ac.kr [Department of Chemistry, Hannam University, 461-6 Jeon min-dong, Yuseoung-gu, Daejeon 305-811 (Korea, Republic of)

    2013-11-01

    We have engineered a metallic architecture with high surface area and ultralow density for applications related to electrochemical supercapacitors. This is achieved first by design and fabrication of new annular collector template for electrospinning process, then the extrusion of polystyrene (PS) nanofiber through the fabricated annulus collector template followed by electroless plating of nanofiber assembly with gold and silver. The resultant three dimensional structures were characterized by optical microscopy (OM), Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The OM images suggest that the fabrication process causes the electrospun fibers to be hinged to one another, maximizing contact junctions enhancing mechanical stability. The coated structure has a superior surface area, is robust, and is freestanding – making it an attractive architectural design for an electrode. The SEM images show interlocking of nanofibers to one another, further indicating the potential application for this system as a high surface area, low density charge collector ideal for nanostructured growths. - Graphical abstract: A new annular collector template was designed and fabricated to create a 3D electrospun nanofiber assembly. This ultralight 3D architecture with high surface was electroless plated with silver and gold to assess its suitability for applications related to electrochemical supercapacitors. This structure is highly conductive leading us to believe that this product can be utilized as an alternate electrode charge collector. - Highlights: • A metallic architecture with high surface area and ultralow density was fabricated. • A new annular collector template for electrospinning was designed and fabricated. • Electrospun PS nanofibers with 3D structure were coated with silver and gold. • The coated structure is

  16. Molecular oxidative stress markers in olive ridley turtles (Lepidochelys olivacea) and their relation to metal concentrations in wild populations.

    Science.gov (United States)

    Cortés-Gómez, Adriana A; Morcillo, Patricia; Guardiola, Francisco A; Espinosa, Cristobal; Esteban, María A; Cuesta, Alberto; Girondot, Marc; Romero, Diego

    2018-02-01

    Due to their longevity and extensive migration areas, marine turtles are able to accumulate diverse contaminants over many years and as a consequence they represent an interesting bioindicator species for marine ecosystem pollution. Metals provoke toxicological effects in many aquatic animal species, but marine turtles have been under-investigated in this area. Thus, we have determined the presence of certain inorganic elements (As, Cd, Cu, Ni, Pb, Se and Zn) in olive ridley turtles (Lepidochelys olivacea) and related them to metallothionein (MT), superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) transcription and/or enzymatic activities. Gene expression of sod, cat and gr was found to be higher in blood than liver or kidney but most of the significant relationships were found in liver, not only for gene expression but also for enzyme activities. This must be related to the role the liver has as the first filter organ. Several positive relationships of sod, cat and gr gene expression in the different tissues were found in this population, as well as very high Cd concentrations. This could mean that these turtles are adapting to the metals-production of ROS and damage through a high transcription of these antioxidants. Multiple positive relationships with GR seem to be part of its compensatory effect due to the decrease of SOD production against the high and chronic exposure to certain xenobiotics. CAT, on the other hand, seems not to be used much, and glutathione detoxification of H 2 O 2 may be more important in this species. Finally, despite the very high Cd concentrations found in this population, no significant relationship was found in any tissue with metallothionein gene expression. These results, along with very high Cd concentrations and a negative relationship with Cu, lead us to consider some kind of disruption in mt gene expression in these turtles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Metallic stent implantation in patients with iliac artery occlusion: long-term patency rate and factors related to recurrence

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Seok Kyun; Kim, Jae Kyu; Yoon, Woong; Kim, Jeong; Park, Jin Gyoon; Kang, Heoung Keun; Choi, Soo JinNa [Chonnam National University Hospital School of Medicine, Gwangju (Korea, Republic of)

    2003-09-01

    To determine the long-term patency rate in 68 patients with iliac artery occlusion who underwent metallic stent implantation, and to analyze the factors related to recurrence. Sixty-eight patients with occlusive disease of the iliac artery underwent implantation of a self-expandable metallic stent. The clinical symptoms were intermittent claudication (n=48), resting pain (n=11), and gangrene (n=9). Stent patency was determined by follow-up angiography and color Doppler imaging, and the cumulative patency rate using the Kaplan-Meier method. Cox's proportional hazard model was used to analyse recurrence-related factors involving clinical symptoms (Fontaine stage), risk factors, and anatomical factors such as lesion location, length, and the development of collaterals. The duration of follow-up varied from 1 day to 73 months (mean, 23.8 months). Arterial occlusion recurred in 16 of 68 patients (23.5%), and the cumulative patency rate was as follows: 95.4% at one month, 93.2% at six months, 80.1% at one year, 73.2% at two years, 68.9% at three years, and 62% at five years. According to a statistical analysis of risk factors, the recurrence (p=0.04) than in those without it, but in patients who smoked, hypertension, DM, and previous cerebrovascular disease were not statistically significant. With regard to anatomical factors, the recurrent rate for lesions involving the external iliac artery was 6.5 times higher (p=0.02) than for those involving the common iliac artery. Variations in the fontaine stage were not statistically significant indicators of recurrence. The recurrence rate after implantation of an iliac artery stent is higher in patients with heart disease than in those without it, and higher for occlusive lesions involving the external iliac artery than for those of the common iliac artery.

  18. Metallic stent implantation in patients with iliac artery occlusion: long-term patency rate and factors related to recurrence

    International Nuclear Information System (INIS)

    Chung, Seok Kyun; Kim, Jae Kyu; Yoon, Woong; Kim, Jeong; Park, Jin Gyoon; Kang, Heoung Keun; Choi, Soo JinNa

    2003-01-01

    To determine the long-term patency rate in 68 patients with iliac artery occlusion who underwent metallic stent implantation, and to analyze the factors related to recurrence. Sixty-eight patients with occlusive disease of the iliac artery underwent implantation of a self-expandable metallic stent. The clinical symptoms were intermittent claudication (n=48), resting pain (n=11), and gangrene (n=9). Stent patency was determined by follow-up angiography and color Doppler imaging, and the cumulative patency rate using the Kaplan-Meier method. Cox's proportional hazard model was used to analyse recurrence-related factors involving clinical symptoms (Fontaine stage), risk factors, and anatomical factors such as lesion location, length, and the development of collaterals. The duration of follow-up varied from 1 day to 73 months (mean, 23.8 months). Arterial occlusion recurred in 16 of 68 patients (23.5%), and the cumulative patency rate was as follows: 95.4% at one month, 93.2% at six months, 80.1% at one year, 73.2% at two years, 68.9% at three years, and 62% at five years. According to a statistical analysis of risk factors, the recurrence (p=0.04) than in those without it, but in patients who smoked, hypertension, DM, and previous cerebrovascular disease were not statistically significant. With regard to anatomical factors, the recurrent rate for lesions involving the external iliac artery was 6.5 times higher (p=0.02) than for those involving the common iliac artery. Variations in the fontaine stage were not statistically significant indicators of recurrence. The recurrence rate after implantation of an iliac artery stent is higher in patients with heart disease than in those without it, and higher for occlusive lesions involving the external iliac artery than for those of the common iliac artery

  19. Fabrication and metallization of 3D electrospun nanofiberous architecture with gold and silver coating for applications related to electrochemical supercapacitors

    International Nuclear Information System (INIS)

    Park, Keon Young; Ramaraj, B.; Choi, Won Suk; Yoon, Kuk Ro

    2013-01-01

    We have engineered a metallic architecture with high surface area and ultralow density for applications related to electrochemical supercapacitors. This is achieved first by design and fabrication of new annular collector template for electrospinning process, then the extrusion of polystyrene (PS) nanofiber through the fabricated annulus collector template followed by electroless plating of nanofiber assembly with gold and silver. The resultant three dimensional structures were characterized by optical microscopy (OM), Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The OM images suggest that the fabrication process causes the electrospun fibers to be hinged to one another, maximizing contact junctions enhancing mechanical stability. The coated structure has a superior surface area, is robust, and is freestanding – making it an attractive architectural design for an electrode. The SEM images show interlocking of nanofibers to one another, further indicating the potential application for this system as a high surface area, low density charge collector ideal for nanostructured growths. - Graphical abstract: A new annular collector template was designed and fabricated to create a 3D electrospun nanofiber assembly. This ultralight 3D architecture with high surface was electroless plated with silver and gold to assess its suitability for applications related to electrochemical supercapacitors. This structure is highly conductive leading us to believe that this product can be utilized as an alternate electrode charge collector. - Highlights: • A metallic architecture with high surface area and ultralow density was fabricated. • A new annular collector template for electrospinning was designed and fabricated. • Electrospun PS nanofibers with 3D structure were coated with silver and gold. • The coated structure is

  20. Structurally related hydrazone-based metal complexes with different antitumor activities variably induce apoptotic cell death.

    Science.gov (United States)

    Megger, Dominik A; Rosowski, Kristin; Radunsky, Christian; Kösters, Jutta; Sitek, Barbara; Müller, Jens

    2017-04-05

    Three new complexes bearing the tridentate hydrazone-based ligand 2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)pyridine (L) were synthesized and structurally characterized. Biological tests indicate that the Zn(ii) complex [ZnCl 2 (L)] is of low cytotoxicity against the hepatocellular carcinoma cell line HepG2. In contrast, the Cu(ii) and Mn(ii) complexes [CuCl 2 (L)] and [MnCl 2 (L)] are highly cytotoxic with EC 50 values of 1.25 ± 0.01 μM and 20 ± 1 μM, respectively. A quantitative proteome analysis reveals that treatment of the cells with the Cu(ii) complex leads to a significantly altered abundance of 102 apoptosis-related proteins, whereas 38 proteins were up- or down-regulated by the Mn(ii) complex. A closer inspection of those proteins regulated only by the Cu(ii) complex suggests that the superior cytotoxic activity of this complex is likely to be related to an initiation of the caspase-independent cell death (CICD). In addition, an increased generation of reactive oxygen species (ROS) and a strong up-regulation of proteins responsive to oxidative stress suggest that alterations of the cellular redox metabolism likely contribute to the cytotoxicity of the Cu(ii) complex.

  1. Relative SHG measurements of metal thin films: Gold, silver, aluminum, cobalt, chromium, germanium, nickel, antimony, titanium, titanium nitride, tungsten, zinc, silicon and indium tin oxide

    Directory of Open Access Journals (Sweden)

    Franklin Che

    Full Text Available We have experimentally measured the surface second-harmonic generation (SHG of sputtered gold, silver, aluminum, zinc, tungsten, copper, titanium, cobalt, nickel, chromium, germanium, antimony, titanium nitride, silicon and indium tin oxide thin films. The second-harmonic response was measured in reflection using a 150 fs p-polarized laser pulse at 1561 nm. We present a clear comparison of the SHG intensity of these films relative to each other. Our measured relative intensities compare favorably with the relative intensities of metals with published data. We also report for the first time to our knowledge the surface SHG intensity of tungsten and antimony relative to that of well known metallic thin films such as gold and silver. Keywords: Surface second-harmonic generation, Nonlinear optics, Metal thin films

  2. Relativity-Induced Bonding Pattern Change in Coinage Metal Dimers M2 (M = Cu, Ag, Au, Rg).

    Science.gov (United States)

    Li, Wan-Lu; Lu, Jun-Bo; Wang, Zhen-Ling; Hu, Han-Shi; Li, Jun

    2018-05-07

    The periodic table provides a fundamental protocol for qualitatively classifying and predicting chemical properties based on periodicity. While the periodic law of chemical elements had already been rationalized within the framework of the nonrelativistic description of chemistry with quantum mechanics, this law was later known to be affected significantly by relativity. We here report a systematic theoretical study on the chemical bonding pattern change in the coinage metal dimers (Cu 2 , Ag 2 , Au 2 , Rg 2 ) due to the relativistic effect on the superheavy elements. Unlike the lighter congeners basically demonstrating ns- ns bonding character and a 0 g + ground state, Rg 2 shows unique 6d-6d bonding induced by strong relativity. Because of relativistic spin-orbit (SO) coupling effect in Rg 2 , two nearly degenerate SO states, 0 g + and 2 u , exist as candidate of the ground state. This relativity-induced change of bonding mechanism gives rise to various unique alteration of chemical properties compared with the lighter dimers, including higher intrinsic bond energy, force constant, and nuclear shielding. Our work thus provides a rather simple but clear-cut example, where the chemical bonding picture is significantly changed by relativistic effect, demonstrating the modified periodic law in heavy-element chemistry.

  3. Cadmium bound to metal rich granules and exoskeleton from Gammarus pulex causes increased gut lipid peroxidation in zebrafish following single dietary exposure

    International Nuclear Information System (INIS)

    Khan, F.R.; Bury, N.R.; Hogstrand, C.

    2010-01-01

    There has been a growing interest in establishing how the sub-cellular distribution of metals in macro-invertebrate prey affects metal trophic bioavailability and toxicity. In this study, the crustacean Gammarus pulex was exposed to 300 μg Cd l -1 spiked with 109 Cd for 13 days, from which the two principal metal containing sub-cellular fractions, the metallothionein-like protein (MTLP) and the metal rich granule and exoskeleton (MRG + exo) were isolated. These fractions were produced at equal metal content, incorporated into gelatin and fed to zebrafish as a single meal; assimilation efficiency (AE), carcass and gut tissue metal concentrations and gut lipid peroxidative damage measured as malondialdehyde (MDA) were assessed. The AE of cadmium bound to the MTLP fraction was 32.1 ± 5.6% which was significantly greater than the AE of MRG + exo bound Cd, 13.0 ± 2.1% (p -1 in fish fed MTLP-Cd compared to 9.5 ± 1.4 ng Cd g -1 in fish fed MRG + exo fraction. Both feeds led to significantly increased MDA levels compared to the control group (gelatin only feed), but MRG + exo feed caused significantly more oxidative damage than the MTLP feed (p < 0.01). Thus, MTLP-Cd is more bioavailable than the cadmium bound to granules and exoskeleton, but it was the latter fraction, largely considered as having limited bioavailability, that appeared to exert a greater localised oxidative injury to the digestive tract of zebrafish.

  4. Iron encrustations on filamentous algae colonized by Gallionella-related bacteria in a metal-polluted freshwater stream

    Science.gov (United States)

    Mori, J. F.; Neu, T. R.; Lu, S.; Händel, M.; Totsche, K. U.; Küsel, K.

    2015-09-01

    Filamentous macroscopic algae were observed in slightly acidic to circumneutral (pH 5.9-6.5), metal-rich stream water that leaked out from a former uranium mining district (Ronneburg, Germany). These algae differed in color and morphology and were encrusted with Fe-deposits. To elucidate their potential interaction with Fe(II)-oxidizing bacteria (FeOB), we collected algal samples at three time points during summer 2013 and studied the algae-bacteria-mineral compositions via confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectra, and a 16S and 18S rRNA gene-based bacterial and algae community analysis. Surprisingly, sequencing analysis of 18S rRNA gene regions of green and brown algae revealed high homologies with the freshwater algae Tribonema (99.9-100 %). CLSM imaging indicated a loss of active chloroplasts in the algae cells, which may be responsible for the change in color in oxidation under the putative oxygen-saturated conditions that occur in association with photosynthetic algae. Quantitative PCR (polymerase chain reaction) revealed even higher Gallionella-related 16S rRNA gene copy numbers on the surface of green algae compared to the brown algae. The latter harbored a higher microbial diversity, including some putative predators of algae. A loss of chloroplasts in the brown algae could have led to lower photosynthetic activities and reduced EPS production, which is known to affect predator colonization. Collectively, our results suggest the coexistence of oxygen-generating algae Tribonema sp. and strictly microaerophilic neutrophilic FeOB in a heavy metal-rich environment.

  5. Kinetics and thermodynamics of ceramic/metal interface reactions related to high T(sub c) superconducting applications

    Science.gov (United States)

    Notis, Michael R.; Oh, Min-Seok

    1990-01-01

    Superconducting ceramic materials, no matter what their form, size or shape, must eventually make contact with non-superconducting materials in order to accomplish current transfer to other parts of a real operating system, or for testing and measurement of properties. Thus, whether the configuration is a clad wire, a bulk superconducting disc, tape, or a thick or thin superconducting film on a substrate, the physical and mechanical behavior of interface (interconnections, joints, etc.) between superconductors and normal conductor materials of all kinds is of extreme importance to the technological development of these systems. Fabrication heat treatments associated with the particular joining process allow possible reactions between the superconducting ceramic and the contact to occur, and consequently influence properties at the interface region. The nature of these reactions is therefore of great broad interest, as these may be a primary determinant for the real capability of these materials. Research related both to fabrication of composite sheathed wire products, and the joining contacts for physical property measurements, as well as, a review of other related literature in the field are described. Comparison are made between 1-2-3, Bi-, and Tl-based ceramic superconductors joined to a variety of metals including Cu, Ni, Fe, Cr, Ag, Ag-Pd, Au, In, and Ga. The morphology of reaction products and the nature of interface degradation as a function of time will be highlighted.

  6. Assessment of the structural relations between the bcc and omega phases of Ti, Zr, Hf and other transition metals

    International Nuclear Information System (INIS)

    Aurelio, G.; Guillermet, A.F.

    2000-01-01

    The name omega (Ω) phase refers to a high-pressure structural modification of the transition metals (TMs) Ti, Zr, and Hf. In alloys of Ti, Zr and Hf with other TMs, the Ω phase can be formed and retained metastably at room temperature by quenching the bcc structure, which is usually the stable high-temperature phase in these alloy systems. As a part of a systematic investigation of the structural and bonding properties of the bcc and Ω phases, and of the bcc → Ω phase transformation in TMs and alloys, we present in this paper a detailed analysis of the structural relations between these phases in Ti, Zr, Hf and in other TMs. The approach is as follows. First, we establish the most general geometrical relations connecting the lattice parameters and interatomic distances (IDs) of the bcc and Ω structures. Next, we focus on the ratio between the relevant IDs of these phases, which are assessed on the basis of an extensive database with experimental and theoretical information. Both stable and metastable structures are considered, and various remarkable regularities in ID ratios are discussed. Finally, in the light of the systematics of ID ratios established in the present work, a discussion is made of the probable lattice parameters for the Ω phase of Hf, which are not yet accurately known from direct measurements. (orig.)

  7. Relations between stellar mass and electron temperature-based metallicity for star-forming galaxies in a wide mass range

    International Nuclear Information System (INIS)

    Shi Wei-Bin; Zhao Gang; Ruan Gui-Ping; Zhou Li; Liang Yan-Chun; Shao Xu; Liu Xiao-Wei; Hammer Francois; Flores Hector; Zhang Yong

    2014-01-01

    We select 947 star-forming galaxies from SDSS-DR7 with [O III]λ4363 emission lines detected at a signal-to-noise ratio larger than 5σ. Their electron temperatures and direct oxygen abundances are then determined. We compare the results from different methods. t 2 , the electron temperature in the low ionization region, estimated from t 3 , that in the high ionization region, is compared using three analysis relations between t 2 – t 3 . These show obvious differences, which result in some different ionic oxygen abundances. The results of t 3 , t 2 , O ++ /H + and O + /H + derived by using methods from IRAF and literature are also compared. The ionic abundances O ++ /H + are higher than O + /H + for most cases. The different oxygen abundances derived from T e and the strong-line ratios show a clear discrepancy, which is more obvious following increasing stellar mass and strong-line ratio R 23 . The sample of galaxies from SDSS with detected [O III]λ4363 have lower metallicites and higher star formation rates, so they may not be typical representatives of the whole population of galaxies. Adopting data objects from Andrews and Martini, Liang et al. and Lee et al. data, we derive new relations of stellar mass and metallicity for star-forming galaxies in a much wider stellar mass range: from 10 6 M ⊙ to 10 11 M ⊙ . (research papers)

  8. Relations among pH, sulfate, and metals concentrations in anthracite and bituminous coal-mine discharges, Pennsylvania

    Science.gov (United States)

    Cravotta, III, Charles A.

    2006-01-01

    Water-quality data for discharges from 140 abandoned mines in the Bituminous and Anthracite Coalfields of Pennsylvania illustrate relations among pH, sulfate, and dissolved metal concentrations. The pH for the 140 samples ranged from 2.7 to 7.3, with two modes at pH 2.5 to 4 (acidic) and 6 to 7 (near neutral). Generally, flow rates were smaller and solute concentrations were greater for low-pH samples; flow rates increased with pH. Although the pH distribution was similar for the bituminous and anthracite subsets, the bituminous discharges had smaller median flow rates, greater concentrations of sulfate, iron, and aluminum, and smaller concentrations of barium and lead than anthracite discharges with the same pH values. The observed relations between the pH and constituent concentrations can be attributed to (1) dilution of acidic water by alkaline ground water; (2) solubility control of aluminum, iron, manganese, barium, and lead by hydroxide, sulfate, and/or carbonate minerals; and (3) aqueous sulfate-complex formation. The formation of AlSO4+ and AlHSO4+2 complexes adds to the total dissolved aluminum concentration at pH of equilibrium with aluminum hydroxide or hydroxysulfate minerals and can account for 10 to 20 times greater concentrations of dissolved aluminum in bituminous discharges compared to anthracite discharges at similar pH. Sulfate complexation also can account for 10 to 30 times greater concentrations of dissolved ferric iron concentrations at equilibrium with ferrihydrite (Fe(OH)3) and/or schwertmannite (Fe8O8(OH)4.5(SO4)1.75) at pH of 3 to 5. In contrast, lower barium and lead concentrations in bituminous than anthracite discharges indicates elevated sulfate concentration could decrease mobility of these metals by the formation of insoluble minerals such as barite (BaSO4) or anglesite (PbSO4). Most samples were saturated with barite, but none were saturated with anglesite. Hence, lead concentrations could be controlled by coprecipitation with

  9. Qualitative relation between heavy metal concentration in soil and agricultural products: a Chinese peri-urban case study

    Science.gov (United States)

    Kikuchi, Ryunosuke; Ferreira, Carla Sofia; Dinis Ferreira, Antonio

    2017-04-01

    A peri-urban area refers to a transition or interaction zone, where urban and rural activities are juxtaposed, and landscape features are subject to rapid modifications, mainly due to human activities. It is reported that peri-urban areas which might include valuable protected areas (e.g. forested hills, preserved woodlands, prime agricultural lands, etc.) can provide essential life support services for urban residents. A peri-urban area is not only a zone experiencing the immediate impacts of land demands from urban growth and pollution, but it is also a wider market-related zone of influence, recognized for the supply of agricultural and natural resource products. It is reported that China's environmental crisis is one of the most pressing challenges to emerge from the country's rapid industrialization; therefore a field study was carried out to investigate the qualitative relation of soil property with vegetable agricultural products in the Chinese peri-urban area located in Luoyang city (34°37'N and 112°27'E). Soil, water and plant (e.g. squash, Cucurbita maxima) samples were taken over the study site, and heavy metal concentrations were analyzed. All the soil samples showed Cd concentrations exceeded the permissible level established by Chinese guidelines for soil quality (0.3 mg/kg). The contents of Zn, Pb and Cu also surpassed the Chinese guideline levels (Zn = 250 mg/kg, Pb = 50 mg/kg and Cu = 100 mg/kg) in several soil samples. Although the sampled plants contained some degree of all the heavy metals, only the Al concentration was high in the Cucurbita maxima samples (317 mg/kg), which is a specie of cultivated squash. Considering the world market and the global trade of agricultural products, it can be said that the food risk associated with farm products containing Al is not local but global. It is concluded that an environmental contamination of the peri-urban areas may lead to the threat to food security.

  10. Role of trace metals in cell proliferation in the human neuroblastoma: relations with the oncogene N-myc

    International Nuclear Information System (INIS)

    Moretto, Ph.; Michelet, C.; Gouget, B.; Ortega, R.; Sergiant, C.; Llabador, Y.; Simonoff, M.; Benard, J.

    1997-01-01

    Neuroblastoma is one of the most common tumors in young children. Iron is known to be necessary for cellular proliferation. Several studies have suggested that neuroblastoma cells appear to be relatively sensitive to growth inhibition by specific Fe chelators, in vitro. In addition, it appeared that an increased serum ferritin level at diagnosis was associated with a poorer outcome than a normal level. On the other hand it was reported that untreated primary neuroblastoma had multiple copies of the N-myc oncogene. A significant association between genomic amplification and rapid tumor progression after diagnosis has been demonstrated. In order to study the relationship between iron N-myc amplification, we propose to determine the trace metal content of neuroblastoma cells. Preliminary results obtained with two distinct cell lines: SK-N-SH, a neuroblastoma cell line with a single copy of N-myc and IGR-N-91, a metastatic cell line exhibiting 60 copies of N-myc are presented. (authors)

  11. Assessment of human health risk related to metals by the use of biomonitors in the province of Cordoba, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Carreras, Hebe A. [Departamento de Quimica, Instituto Multidisciplinario de Biologia Vegetal, IMBIV/CONICET-UNC, Facultad de Ciencias Exactas, Fisicas y Naturales, Universidad Nacional de Cordoba, Av. Velez Sarsfield 1611, Ciudad Universitaria, X5016GCA Cordoba (Argentina)], E-mail: hcarreras@com.uncor.edu; Wannaz, Eduardo D.; Pignata, Maria L. [Departamento de Quimica, Instituto Multidisciplinario de Biologia Vegetal, IMBIV/CONICET-UNC, Facultad de Ciencias Exactas, Fisicas y Naturales, Universidad Nacional de Cordoba, Av. Velez Sarsfield 1611, Ciudad Universitaria, X5016GCA Cordoba (Argentina)

    2009-01-15

    The evaluation of metal contents in the environment is of vital importance for the assessment of human exposure. Thus the species Usnea amblyoclada, Ramalina celastri and Tillandsia capillaris were tested as bioaccumulators of transition metals in the urban area of Cordoba city, Argentina. The level of metals on biomonitors was compared to that of total deposition samples. All three species discriminated zones within the urban area of Cordoba city with different pollution levels; they revealed high levels of Zn in the downtown area and confirmed high levels of some transition metals in an industrial area. The correlation analysis revealed that the lichen R. celastri had the highest correlation rates with total deposition samples, suggesting it is a valuable biomonitor of atmospheric pollution. A significant relationship was also observed between respiratory diseases in children and the contents of metal accumulated in R. celastri and T. capillaris, indicating their usefulness when assessing human exposure to metals. - Metal accumulation in epiphytes is correlated with human respiratory diseases.

  12. Assessment of human health risk related to metals by the use of biomonitors in the province of Cordoba, Argentina

    International Nuclear Information System (INIS)

    Carreras, Hebe A.; Wannaz, Eduardo D.; Pignata, Maria L.

    2009-01-01

    The evaluation of metal contents in the environment is of vital importance for the assessment of human exposure. Thus the species Usnea amblyoclada, Ramalina celastri and Tillandsia capillaris were tested as bioaccumulators of transition metals in the urban area of Cordoba city, Argentina. The level of metals on biomonitors was compared to that of total deposition samples. All three species discriminated zones within the urban area of Cordoba city with different pollution levels; they revealed high levels of Zn in the downtown area and confirmed high levels of some transition metals in an industrial area. The correlation analysis revealed that the lichen R. celastri had the highest correlation rates with total deposition samples, suggesting it is a valuable biomonitor of atmospheric pollution. A significant relationship was also observed between respiratory diseases in children and the contents of metal accumulated in R. celastri and T. capillaris, indicating their usefulness when assessing human exposure to metals. - Metal accumulation in epiphytes is correlated with human respiratory diseases

  13. On the relation between the ratio of energy of vaporization to activation energy for flow and physical properties of liquid metals

    International Nuclear Information System (INIS)

    Dutt, N.V.K.; Ravikumar, Y.V.L.; Prasad, D.H.L.

    1993-01-01

    A relation between the ratio of energy of vaporization (Esub(vap) to the activation energy for flow (Esub(vis)) and the ratio of melting point (T m ) to the critical temperature (T c ) has been developed for liquid metals, and is shown to be superior to the examinations from Eyring theory. (author). 12 refs

  14. Heavy metal burden in coastal marine sediments of north west coast of India in relation to pollution

    Digital Repository Service at National Institute of Oceanography (India)

    Rokade, M.A.

    the concentrations of potentially toxic metals (Flegal and Wilhelmy, 1991; Hornberger et al., 1999). 6 Between 1850 and 1900 most of the Hg mining in the world occurred in the watershed of the San Francisco Bay. Hydraulic mining for gold mobilized sediments... to the ocean bottom water (about 0.2 8 μg/l). When anoxic diagenesis takes over, reduction of Fe also occurs with high levels of both the metals in pore waters. Several trace metals that are bound to particle surfaces are also mobilized with Mn and Fe...

  15. Catalytic ozonation not relying on hydroxyl radical oxidation: A selective and competitive reaction process related to metal-carboxylate complexes

    KAUST Repository

    Zhang, Tao; Croue, Jean-Philippe

    2014-01-01

    Catalytic ozonation following non-hydroxyl radical pathway is an important technique not only to degrade refractory carboxylic-containing organic compounds/matter but also to avoid catalyst deactivation caused by metal-carboxylate complexation

  16. The Role of Metal Binding in the Amyotrophic Lateral Sclerosis-Related Aggregation of Copper-Zinc Superoxide Dismutase

    Directory of Open Access Journals (Sweden)

    Ivana Sirangelo

    2017-08-01

    Full Text Available Protein misfolding and conformational changes are common hallmarks in many neurodegenerative diseases involving formation and deposition of toxic protein aggregates. Although many players are involved in the in vivo protein aggregation, physiological factors such as labile metal ions within the cellular environment are likely to play a key role. In this review, we elucidate the role of metal binding in the aggregation process of copper-zinc superoxide dismutase (SOD1 associated to amyotrophic lateral sclerosis (ALS. SOD1 is an extremely stable Cu-Zn metalloprotein in which metal binding is crucial for folding, enzymatic activity and maintenance of the native conformation. Indeed, demetalation in SOD1 is known to induce misfolding and aggregation in physiological conditions in vitro suggesting that metal binding could play a key role in the pathological aggregation of SOD1. In addition, this study includes recent advances on the role of aberrant metal coordination in promoting SOD1 aggregation, highlighting the influence of metal ion homeostasis in pathologic aggregation processes.

  17. A CRITICAL LOOK AT THE MASS-METALLICITY-STAR FORMATION RATE RELATION IN THE LOCAL UNIVERSE. I. AN IMPROVED ANALYSIS FRAMEWORK AND CONFOUNDING SYSTEMATICS

    Energy Technology Data Exchange (ETDEWEB)

    Salim, Samir; Salzer, John J. [Department of Astronomy, Indiana University, Bloomington, IN 47404 (United States); Lee, Janice C. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Ly, Chun [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Brinchmann, Jarle [Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands); Davé, Romeel [University of the Western Cape, Bellville, Cape Town 7535 (South Africa); Dickinson, Mark [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Charlot, Stéphane, E-mail: salims@indiana.edu [Institut d' Astrophysique de Paris, CNRS, F-75014 Paris (France)

    2014-12-20

    It has been proposed that the (stellar) mass-(gas) metallicity relation of galaxies exhibits a secondary dependence on star formation rate (SFR), and that the resulting M {sub *}-Z-SFR relation may be redshift-invariant, i.e., ''fundamental''. However, conflicting results on the character of the SFR dependence, and whether it exists, have been reported. To gain insight into the origins of the conflicting results, we (1) devise a non-parametric, astrophysically motivated analysis framework based on the offset from the star-forming ({sup m}ain{sup )} sequence at a given M {sub *} (relative specific SFR); (2) apply this methodology and perform a comprehensive re-analysis of the local M {sub *}-Z-SFR relation, based on SDSS, GALEX, and WISE data; and (3) study the impact of sample selection and of using different metallicity and SFR indicators. We show that metallicity is anti-correlated with specific SFR regardless of the indicators used. We do not find that the relation is spurious due to correlations arising from biased metallicity measurements or fiber aperture effects. We emphasize that the dependence is weak/absent for massive galaxies (log M {sub *} > 10.5), and that the overall scatter in the M {sub *}-Z-SFR relation does not greatly decrease from the M {sub *}-Z relation. We find that the dependence is stronger for the highest SSFR galaxies above the star-forming sequence. This two-mode behavior can be described with a broken linear fit in 12+log(O/H) versus log (SFR/M {sub *}), at a given M {sub *}. Previous parameterizations used for comparative analysis with higher redshift samples that do not account for the more detailed behavior of the local M {sub *}-Z-SFR relation may incorrectly lead to the conclusion that those samples follow a different relationship.

  18. Global DNA methylation in earthworms: A candidate biomarker of epigenetic risks related to the presence of metals/metalloids in terrestrial environments

    Energy Technology Data Exchange (ETDEWEB)

    Maldonado Santoyo, Maria; Rodriguez Flores, Crescencio; Lopez Torres, Adolfo; Wrobel, Kazimierz [Department of Chemistry, University of Guanajuato, L de Retana No 5, 36000 Guanajuato (Mexico); Wrobel, Katarzyna, E-mail: katarzyn@quijote.ugto.mx [Department of Chemistry, University of Guanajuato, L de Retana No 5, 36000 Guanajuato (Mexico)

    2011-10-15

    In this work, possible relationships between global DNA methylation and metal/metalloid concentrations in earthworms have been explored. Direct correlation was observed between soil and tissue As, Se, Sb, Zn, Cu, Mn, Ag, Co, Hg, Pb (p < 0.05). Speciation results obtained for As and Hg hint at the capability of earthworms for conversion of inorganic element forms present in soil to methylated species. Inverse correlation was observed between the percentage of methylated DNA cytosines and total tissue As, As + Hg, As + Hg + Se + Sb ({beta} = -0.8456, p = 0.071; {beta} = -0.9406, p = 0.017; {beta} = -0.9526, p = 0.012 respectively), as well as inorganic As + Hg ({beta} = -0.8807, p = 0.049). It was concluded that earthworms would be particularly helpful as bioindicators of elements undergoing in vivo methylation and might also be used to assess the related risk of epigenetic changes in DNA methylation. - Graphical abstract: Display Omitted Highlights: > Several metals and metalloids contribute to epigenetic gene regulation. > As, Hg, Se, Sb inversely correlated with global DNA methylation in earthworms. > Biomethylation of the above elements in worms suggested. > Elements biomethylation apparently competes with DNA methylation. > DNA methylation a biomarker of epigenetic risks related to soil metals/metalloids. - Biomethylation of As, Hg in earthworms versus DNA methylation - a candidate biomarker of epigenetic risks related to the presence of metals/metalloids in soil.

  19. Mechanistic studies related to the metal catalyzed reduction of carbon monoxide to hydrocarbons. Final report, April 1, 1977-June 30, 1985

    International Nuclear Information System (INIS)

    Casey, C.P.

    1985-02-01

    Studies of compounds related to proposed intermediates in the hydrogenation of carbon monoxide over homogeneous and heterogeneous catalysts have been carried out. The synthesis, structure, and reactions of metal formyl compounds have been investigated. The synthesis and desproportionation reactions of hydroxymethyl metal compounds have been explored. Reactions involving interconversion of n 5 - and n'-C 5 H 5 organometallic compounds have been discovered. New synthetic routes to bimetallic compounds with bridging hydrocarbon ligands have been developed. The first bimetallic compound with a budging CH ligand has been prepared. The hydrocarbation reaction in which the CH bond of a bridging methylidyne complex adds across a carbon-carbon double bond has been discovered. New heterobimetallic compounds linked by a heterodifunctional ligand and heterobimetallic compounds with directly bonded early and late transition metals have been synthesized in a search for new CO hydrogenation catalysts. 36 refs

  20. Concentrations of trace elements in human tissues and relation of ratios of mutual metals to the human health

    International Nuclear Information System (INIS)

    Ling-wei, X.; Shao-xian, L.; Xiao-juan, Z.

    1989-01-01

    According to the experimental results, the concentrations and concentrations in order, of trace elements in human tissues among Changsha's People in China are reported. The authors particularly present that the ratios of mutual metals (M/N) in normal physiological tissues and fluids are very important factors which indicate the metabolic situations of trace elements in the body and as the indices which evaluate the situation of human health. (M and N mean the concentrations of different trace elements in the tissues or fluids, respectively.) Up to now, it is still an interesting field to study the functions of trace elements for the human health. There are previously some reports about the concentrations of trace elements in normal physiological tissues/ or organs and fluids of human body. These provide very valuable data for biological medicine. In the study presented atomic absorption method was adopted in order to determine the concentrations of Zn, Cu, Mn, Ni, Pb and Cd in human tissues (liver, spleen, kidney, bone, lung, pancreas, heart and artery and muscle) at autopsy. The authors suggest that trace elements, are contained in the body in an aproportional way, in normal physiological tissues and fluids, and the ratios may directly indicate metabolic situation of trace elements in the body which further reveal the mystery of trace elements for human health. Therefore, the ratios M/N as an indicator of health is more proper than that only using concentrations of trace elements. Schroeder (1973) reported that incidence of heart disease is related to the imbalance of ration Zn/Cd and Zn/Cu rather than the concentrations of Zn, Cd, Cu, and the intellectual development also depends on the proper proportion among copper, cadmium, lead, zinc in the body

  1. Metal concentrations in Unio pictorum mancus (Mollusca, Lamellibranchia from of 12 Northern Italian lakes in relation to their trophic level

    Directory of Open Access Journals (Sweden)

    Paolo LODIGIANI

    2003-08-01

    Full Text Available This research aims to test the reliability of environmental monitoring by bioaccumulators of pollutants; that is to establish a positive relationship between the pollutant concentrations in the bioaccumulator and those in the water in which it lives. To this end we analysed the contents of Al, Cu, Zn, Fe, Mn and Ca in the soft tissues and shell of Unio pictorum mancus. The filtered water samples from the mussel habitat were analysed for the same metals. The mussels were collected from 15 stations settled in 12 Northern Italian lakes during the first two weeks of July 2001. These results were obtained: a metal concentrations varied widely with mussel size and among stations; b a significant positive correlation between the concentration of calcium in the water and in the mussel tissues, but no relationship emerged for the other metals; c no relationship between the metal concentrations in the tissues and those in the shell was found; d there was a certain tendency for Mn, Fe and Zn concentrations in the soft tissues to increase with shell size; e the sequence of the decreasing metal concentrations arranged for the tissues was similar to that of the shell, but rather different from that in the water; and f the concentration factor values of the trace metals were high for the shell and soft tissues. In highly productive lakes large size mussels dominated, whereas small mussels were more abundant in low productive lakes. Although the metal concentrations in the water of productive lakes were greater than in low productive ones, the metal concentrations in the tissues of the mussels from the latter were generally higher than those in the mussels from the former. We propose some hypotheses to explain this paradox. Finally, our results show that the metal concentrations in the mussels do not reflect the metal concentrations in the water in which they live. It follows that this commonly used but oversimplified monitoring system cannot be recommended. On

  2. Geochemical behavior and environmental risks related to the use of abandoned base-metal tailings as construction material in the upper-Moulouya district, Morocco.

    Science.gov (United States)

    Argane, R; El Adnani, M; Benzaazoua, M; Bouzahzah, H; Khalil, A; Hakkou, R; Taha, Y

    2016-01-01

    In some developing countries, base-metal residues that were abandoned in tailing ponds or impoundments are increasingly used as construction material without any control, engineering basis, or environmental concern. This uncontrolled reuse of mine tailings may constitute a new form of pollution risks for humans and ecosystems through metal leaching. Therefore, the aim of the current study is to assess mine drainage, metal mobility, and geochemical behavior of two abandoned mine tailings commonly used in the upper-Moulouya region (eastern Morocco) as fine aggregates for mortar preparation. Their detailed physical, chemical, and mineralogical properties were subsequently evaluated in the context of developing appropriate alternative reuses to replace their conventional disposal and limit their weathering exposure. The obtained results showed that both tailings contain relatively high quantities of residual metals and metalloids with lead (ranging between 3610 and 5940 mg/kg) being the major pollutant. However, the mineralogical investigations revealed the presence of abundant neutralizing minerals and low sulfide content which influence mine drainage geochemistry and subsequently lower metals mobility. In fact, leachate analyses from weathering cell kinetic tests showed neutral conditions and low sulfide oxidation rates. According to these results, the tailings used as construction material in the upper-Moulouya region have very low generating potential of contaminated effluents and their reuse as aggregates may constitute a sustainable alternative method for efficient tailing management.

  3. Heavy metal distributions in Peru Basin surface sediments in relation to historic, present and disturbed redox environments

    Science.gov (United States)

    Koschinsky, Andrea

    Heavy metal distributions in deep-sea surface sediments and pore water profiles from five areas in the Peru Basin were investigated with respect to the redox environment and diagenetic processes in these areas. The 10-20-cm-thick Mn oxide-rich and minor metal-rich top layer is underlain by an increase in dissolved Mn and Ni concentrations resulting from the reduction of the MnO 2 phase below the oxic zone. The mobilised associated metals like Co, Zn and Cu are partly immobilised by sorption on clay, organic or Fe compounds in the post-oxic environment. Enrichment of dissolved Cu, Zn, Ni, Co, Pb, Cd, Fe and V within the upper 1-5 cm of the oxic zone can be attributed to the degradation of organic matter. In a core from one area at around 22-25 cm depth, striking enrichments of these metals in dissolved and solid forms were observed. Offset distributions between oxygen penetration and Mn reduction and the thickness of the Mn oxide-rich layer indicate fluctuations of the Mn redox boundary on a short-term time scale. Within the objectives of the German ATESEPP research programme, the effect of an industrial impact such as manganese nodule mining on the heavy metal cycle in the surface sediment was considered. If the oxic surface were to be removed or disturbed, oxygen would penetrate deep into the formerly suboxic sediment and precipitate Mn 2+ and metals like Ni and Co which are preferably scavenged by MnO 2. The solid enrichments of Cd, V, and other metals formed in post-oxic environments would move downward with the new redox boundary until a new equilibrium between oxygen diffusion and consumption is reached.

  4. Relation between the electrolytic solution pressures of the metals and their toxicity to the stickleback (Gasterosteus acelueatus l. )

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J R.E.

    1939-01-01

    Lethal concentration limits have been determined for the hydrogen ion and the ions of eighteen metals. The three-spined stickleback (Gasterosteus aculeatus l.) has been employed as test animal. According to their lethal concentration limits on a mg./l. basis their order of increasing toxicity is: Sr, Ca, Na, Ba, Mg, K, Mn, Co, Cr, Ni, Au, Zn, Cd, Pb, Al, Cu, H, Hg, and Ag. On a molar concentration basis the order is as follows: Na, Ca, Sr, Mg, Ba, K, Mn, Co, Cr, Ni, H, Zn, Al, Au, Cd, Pb, Cu, Hg, Ag. All these ions, with the exception of the first six (the metals of the alkalis and alkaline earths), bring about the death of fish by precipitating the gill secretions, thus causing asphyxiation. The alkali and alkaline earth metals appear to enter the body and act as true internal poisons. The position of iron is uncertain. The toxicity of solutions of iron salts appears to be due, mainly if not entirely, to their acidity. On a mg./l. or molar concentration basis there is a marked relationship between the toxicity of the metals and their solution pressures. The metals of very low solution pressure (Ag, Cu, etc.), i.e. those whose ions are most ready to part with their charges and enter into combination with other ions or compounds, are the most toxic as they precipitate the gill secretions and bring about asphyxiation with extreme rapidity. Metals of somewhat higher solution pressure (Zn, Pb, Cd) act in the same way but more slowly. Manganese, which of all the heavy metals has the highest solution pressure, takes effect very slowly and the ions of the alkali and alkaline earth metals, which have a high affinity for their charges, do not precipitate the gill secretions at all. In the case of all ions other than those of the alkali and alkaline earth metals the reactions responsible for the death of the fish take place outside the body. Thus their speed of action does not depend on their penetrating power and the permeability factor does not enter.

  5. Assessing ecotoxicity and uptake of metals and metalloids in relation to two different earthworm species (Eiseina hortensis and Lumbricus terrestris)

    International Nuclear Information System (INIS)

    Leveque, Thibaut; Capowiez, Yvan; Schreck, Eva; Mazzia, Christophe; Auffan, Mélanie; Foucault, Yann; Austruy, Annabelle; Dumat, Camille

    2013-01-01

    Due to diffuse atmospheric fallouts of process particles enriched by metals and metalloids, polluted soils concern large areas at the global scale. Useful tools to assess ecotoxicity induced by these polluted soils are therefore needed. Earthworms are currently used as biotest, however the influence of specie and earthworm behaviour, soil characteristics are poorly highlighted. Our aim was therefore to assess the toxicity of various polluted soils with process particles enriches by metals and metalloids (Pb, Cd, Cu, Zn, As and Sb) collected from a lead recycling facility on two earthworm species belonging to different ecological types and thus likely to have contrasted behavioural responses (Eiseina hortensis and Lumbricus terrestris). The combination of behavioural factors measurements (cast production and biomass) and physico-chemical parameters such as metal absorption, bioaccumulation by earthworms and their localization in invertebrate tissues provided a valuable indication of pollutant bioavailability and ecotoxicity. Soil characteristics influenced ecotoxicity and metal uptake by earthworms, as well as their soil bioturbation. -- Highlights: •Historically polluted soils collected from a lead recycling facility were studied. •Cast production is a sensitive parameter to assess ecotoxicity on earthworms. •Both soil parameters, like organic matter content and pH and earthworm specie influence metal uptake and ecotoxicity. -- Behavioural factors and inorganic pollutant uptake by earthworms provide a valuable indication of bioavailability and ecotoxicity

  6. A guidance manual for estimating greenhouse gas emissions from fuel combustion and process-related sources for primary base metals smelting and refining

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-03-01

    This technical guidance manual is a useful resource for helping the metals industry compile inventories of its greenhouse gas (GHG) emissions. The guidance is consistent with Canada's national GHG accounting methodologies. It provides information to smelters and refiners of base metals on how to estimate their GHG emissions from fuel combustion and specific process-related activities. The base metals group in this manual included copper, nickel, lead, zinc, and cobalt. Fuel combustion includes all stationary combustion activities for generating heat or work, and includes waste incineration if the waste heat is used for energy. It also includes mobile fuel combustion activities such as on-site transportation of raw materials from one process to another. Guidance is provided for carbon dioxide (CO{sub 2}), methane (CH{sub 4}) and nitrous oxide (N{sub 2}O). Process-related activities include specific industrial processes that contribute to GHG emissions. For base metal smelting, this includes CO{sub 2} emissions from use of carbonate reagents, use of reducing agents, electrode consumption, and hydrofluorocarbons (HFC) emissions from use in refrigeration systems. This document also included sections on quality assurance; aspects of uncertainty assessment; verification; and, reporting of emissions information. refs., tabs., figs.

  7. Metals in urine in relation to the prevalence of pre-diabetes, diabetes and atherosclerosis in rural India.

    Science.gov (United States)

    Velmurugan, Ganesan; Swaminathan, Krishnan; Veerasekar, Ganesh; Purnell, Jonathan Q; Mohanraj, Sundaresan; Dhivakar, Mani; Avula, Anil Kumar; Cherian, Mathew; Palaniswami, Nalla G; Alexander, Thomas; Pradeep, Thalappil

    2018-04-19

    Diabetes and cardiovascular diseases are growing burdens in rural communities worldwide. We have observed a high prevalence of diabetes among rural farming communities in India and sought to evaluate the association of non-traditional risk factors, such as metals, with diabetes and other cardiometabolic risk factors in this community. Anthropometric measurements, chemistries and carotid intima-media thickness were determined in 865 participants of the Kovai Medical Center and Hospital-Nallampatti Non-Communicable Disease Study-I (KMCH-NNCD-I, 2015), a cross-sectional study conducted in a farming village in South India. Urinary metal levels were determined by inductively couped plasma-mass spectrometry analysis and corrected to urinary creatinine level. Statistical analyses were performed to study the association between urinary metal levels and clinical parameters. 82.5% of the study population were involved in farming and high levels of toxic metals were detected in the synthetic fertilisers used in the study village. The prevalence of pre-diabetes, diabetes and atherosclerosis was 43.4%, 16.2% and 10.3%, respectively. On logistic regression analysis, no association of traditional risk factors such as body mass index, blood pressure and total cholesterol with disease conditions was observed, but urinary levels of metals such as arsenic, chromium, aluminium and zinc showed an association with diabetes, while arsenic and zinc showed an association with pre-diabetes and atherosclerosis. Our data suggest a probable role of metals in the aetiology of diabetes and cardiovascular diseases in rural communities. Identifying and eliminating the causes of increased levels of these environmental chemicals could have a beneficial impact on the burden of non-communicable diseases in rural population. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly

  8. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Fatigue life of metal treated by magnetic field

    Science.gov (United States)

    Liu, Zhao-Long; Hu, Hai-Yun; Fan, Tian-You; Xing, Xiu-San

    2009-03-01

    This paper investigates theoretically the influence of magnetization on fatigue life by using non-equilibrium statistical theory of fatigue fracture for metals. The fatigue microcrack growth rate is obtained from the dynamic equation of microcrack growth, where the influence of magnetization is described by an additional term in the potential energy of microcrack. The statistical value of fatigue life of metal under magnetic field is derived, which is expressed in terms of magnetic field and macrophysical as well as microphysical quantities. The fatigue life of AISI 4140 steel in static magnetic field from this theory is basically consistent with the experimental data.

  9. Evolution of the mass-metallicity relations in passive and star-forming galaxies from SPH-cosmological simulations

    DEFF Research Database (Denmark)

    Velonà, A. D Romeo; Sommer-Larsen, J.; Napolitano, N. R.

    2013-01-01

    at high redshift, whose scatter increases with time alongside the consolidation of the passive sequence. We also confirm the anti-correlation between sSFR and stellar mass, pointing at a key role of the former in determining the galaxy downsizing, as the most significant means of diagnostics of the star...... formation efficiency. Likewise, an anti-correlation between sSFR and metallicity can be established for the SF galaxies, while on the contrary more active galaxies in terms of simple SFR are also metal-richer. Finally, the [O/Fe] abundance ratio is presented too: we report a strong increasing evolution...

  10. Mobilisation of heavy metals into the urine by CaEDTA: relation to erythrocyte and plasma concentrations and exposure indicators.

    OpenAIRE

    Araki, S; Aono, H; Murata, K

    1986-01-01

    To investigate the effects of calcium disodium ethylenediamine tetra-acetate (CaEDTA) on the urinary excretion, erythrocyte, and plasma concentrations and exposure indicators of seven heavy metals, CaEDTA was administered by intravenous infusion to 20 workers exposed to lead, zinc, and copper. The workers' blood lead concentrations ranged from 22 to 59 micrograms/dl (mean 38 micrograms/dl (1.8 mumol/l]. The 24 hour urinary excretion of metals after CaEDTA administration (mobilisation yield) w...

  11. Metal interactions with boron clusters

    International Nuclear Information System (INIS)

    Grimes, R.N.

    1982-01-01

    This book presents information on the following topics: the structural and bonding features of metallaboranes and metallacarboranes; transition-metal derivatives of nido-boranes and some related species; interactions of metal groups with the octahydrotriborate (1-) anion, B 3 H 8 ; metallaboron cage compounds of the main group metals; closo-carborane-metal complexes containing metal-carbon and metal-boron omega-bonds; electrochemistry of metallaboron cage compounds; and boron clusters with transition metal-hydrogen bonds

  12. Comparison of Structurally–Related Alkoxide, Amine, and Thiolate–Ligated MII (M= Fe, Co) Complexes: the Influence of Thiolates on the Properties of Biologically Relevant Metal Complexes

    Science.gov (United States)

    Brines, Lisa M.; Villar-Acevedo, Gloria; Kitagawa, Terutaka; Swartz, Rodney D.; Lugo-Mas, Priscilla; Kaminsky, Werner; Benedict, Jason B.; Kovacs, Julie A.

    2009-01-01

    Mechanistic pathways of metalloenzymes are controlled by the metal ion’s electronic and magnetic properties, which are tuned by the coordinated ligands. The functional advantage gained by incorporating cysteinates into the active site of non-heme iron enzymes such as superoxide reductase (SOR) is not entirely understood. Herein we compare the structural and redox properties of a series of structurally–related thiolate, alkoxide, and amine–ligated Fe(II) complexes in order to determine how the thiolate influences properties critical to function. Thiolates are shown to reduce metal ion Lewis acidity relative to alkoxides and amines, and have a strong trans influence thereby helping to maintain an open coordination site. Comparison of the redox potentials of the structurally analogous compounds described herein indicates that alkoxide ligands favor the higher-valent Fe3+ oxidation state, amine ligands favor the reduced Fe2+ oxidation state, and thiolates fall somewhere in between. These properties provide a functional advantange for substrate reducing enzymes in that they provide a site at the metal ion for substrate to bind, and a moderate potential that facilitates both substrate reduction, and regeneration of the catalytically active reduced state. Redox potentials for structurally–related Co(II) complexes are shown to be cathodically–shifted relative to their Fe(II) analogues, making them ineffective reducing agents for substrates such as superoxide. PMID:21731109

  13. A local leaky-box model for the local stellar surface density-gas surface density-gas phase metallicity relation

    Science.gov (United States)

    Zhu, Guangtun Ben; Barrera-Ballesteros, Jorge K.; Heckman, Timothy M.; Zakamska, Nadia L.; Sánchez, Sebastian F.; Yan, Renbin; Brinkmann, Jonathan

    2017-07-01

    We revisit the relation between the stellar surface density, the gas surface density and the gas-phase metallicity of typical disc galaxies in the local Universe with the SDSS-IV/MaNGA survey, using the star formation rate surface density as an indicator for the gas surface density. We show that these three local parameters form a tight relationship, confirming previous works (e.g. by the PINGS and CALIFA surveys), but with a larger sample. We present a new local leaky-box model, assuming star-formation history and chemical evolution is localized except for outflowing materials. We derive closed-form solutions for the evolution of stellar surface density, gas surface density and gas-phase metallicity, and show that these parameters form a tight relation independent of initial gas density and time. We show that, with canonical values of model parameters, this predicted relation match the observed one well. In addition, we briefly describe a pathway to improving the current semi-analytic models of galaxy formation by incorporating the local leaky-box model in the cosmological context, which can potentially explain simultaneously multiple properties of Milky Way-type disc galaxies, such as the size growth and the global stellar mass-gas metallicity relation.

  14. Relation between the amount of dissolved water and metals dissolved from stainless steel or aluminum plate in safflower oil

    Energy Technology Data Exchange (ETDEWEB)

    Takasago, Masahisa; Takaoka, Kyo

    1986-12-01

    The amount of water dissolved in safflower oil at the frying temperature (180 deg C) was 518 -- 1012 ppM, allowing water to drop continuously (0.035 g/2 min) into the oil for 1 -- 3 h. When the oil was heated with metal plates under the same conditions, the amount of dissolved water in the oil increased more than in the absence of the metal plates. In case of stainless steel, the amount was 1.26 to 1.33 times, and with aluminum plates, 1.06 to 1.13 times the amount without plates. When these metal plates were heated with the oil under the above conditions, the water dissolved the metal of the plates into the oil. In case of stainless steel, iron dissolved from 0.17 to 0.77 ppM, nickel, 0.04 ppM and chromium, from 0.02 to 0.03 ppM. Similarly, the amount of aluminum dissolved from the aluminum plate was from 0.10 to 0.45 ppM.

  15. The relation between the amount of dissolved water and metals dissolved from stainless steel or aluminum plate in safflower oil

    International Nuclear Information System (INIS)

    Takasago, Masahisa; Takaoka, Kyo

    1986-01-01

    The amount of water dissolved in safflower oil at the frying temperature (180 deg C) was 518 ∼ 1012 ppm, allowing water to drop continuously (0.035 g/2 min) into the oil for 1 ∼ 3 h. When the oil was heated with metal plates under the same conditions, the amount of dissolved water in the oil increased more than in the absence of the metal plates. In case of stainless steel, the amount was 1.26 to 1.33 times, and with aluminum plates, 1.06 to 1.13 times the amount without plates. When these metal plates were heated with the oil under the above conditions, the water dissolved the metal of the plates into the oil. In case of stainless steel, iron dissolved from 0.17 to 0.77 ppm, nickel, 0.04 ppm and chromium, from 0.02 to 0.03 ppm. Similarly, the amount of aluminum dissolved from the aluminum plate was from 0.10 to 0.45 ppm. (author)

  16. Fate of Metals in Relation to Water and Sediment Properties in a Subtropical Lake in Central Himalaya, India.

    Science.gov (United States)

    Inaotombi, Shaikhom; Gupta, Prem Kumar

    2017-04-01

    Lakes of Himalaya are one of the most fragile ecosystems on earth. Tourism and urban development in the upland region strongly affect its water resources. The high rate of sedimentation and organic matter deposition alters the ecological state of sediment bed, which indirectly influences on dynamics of metallic elements. We investigated spatial and temporal variations of water and sediment characteristic in Lake Sattal of Central Himalaya, India. Samples were collected seasonally from four sampling locations from January 2011 to December 2012. Pearson's correlation and Canonical correspondence analysis (CCAs) were applied to examine the dynamics and behaviors of heavy metals. Concentrations of elements were in the order of fluoride (Fl) > zinc (Zn) > copper (Cu) > iron (Fe) > manganese (Mn). Sand size fraction was higher in the littoral zone while clay particle was dominant in the profundal zone of the lake. Dissolved oxygen at sediment-water-interface (SWI) and water temperature were the major factors influencing the dynamics of metallic contents in the water column. Spatially, total organic matter (TOM) was higher in the deeper portion of the lake. Our study revealed that mobility of Fe is temperature-dependent, whereas speciation of Mn and Cu are primarily controlled by the suboxic condition of SWI in organic-rich site. Upland lakes are more vulnerable to anoxic condition and have severe implications on heavy metals speciation. Proper implementation of land use policies and management practices, including stormwater detention, can be integrated into resolving such problems.

  17. Heavy metal accumulation related to population density in road dust samples taken from urban sites under different land uses

    NARCIS (Netherlands)

    Trujillo-González, Juan Manuel; Torres-Mora, Marco Aurelio; Keesstra, Saskia; Brevik, Eric C.; Jiménez-Ballesta, Raimundo

    2016-01-01

    Soil pollution is a key component of the land degradation process, but little is known about the impact of soil pollution on human health in the urban environment. The heavy metals Pb, Zn, Cu, Cr, Cd and Ni were analyzed by acid digestion (method EPA 3050B) and a total of 15 dust samples were

  18. Application of multivariate statistical analysis in the pollution and health risk of traffic-related heavy metals.

    Science.gov (United States)

    Ebqa'ai, Mohammad; Ibrahim, Bashar

    2017-12-01

    This study aims to analyse the heavy metal pollutants in Jeddah, the second largest city in the Gulf Cooperation Council with a population exceeding 3.5 million, and many vehicles. Ninety-eight street dust samples were collected seasonally from the six major roads as well as the Jeddah Beach, and subsequently digested using modified Leeds Public Analyst method. The heavy metals (Fe, Zn, Mn, Cu, Cd, and Pb) were extracted from the ash using methyl isobutyl ketone as solvent extraction and eventually analysed by atomic absorption spectroscopy. Multivariate statistical techniques, principal component analysis (PCA), and hierarchical cluster analysis were applied to these data. Heavy metal concentrations were ranked according to the following descending order: Fe > Zn > Mn > Cu > Pb > Cd. In order to study the pollution and health risk from these heavy metals as well as estimating their effect on the environment, pollution indices, integrated pollution index, enrichment factor, daily dose average, hazard quotient, and hazard index were all analysed. The PCA showed high levels of Zn, Fe, and Cd in Al Kurnish road, while these elements were consistently detected on King Abdulaziz and Al Madina roads. The study indicates that high levels of Zn and Pb pollution were recorded for major roads in Jeddah. Six out of seven roads had high pollution indices. This study is the first step towards further investigations into current health problems in Jeddah, such as anaemia and asthma.

  19. Assessing ecotoxicity and uptake of metals and metalloids in relation to two different earthworm species (Eiseina hortensis and Lumbricus terrestris).

    Science.gov (United States)

    Leveque, Thibaut; Capowiez, Yvan; Schreck, Eva; Mazzia, Christophe; Auffan, Mélanie; Foucault, Yann; Austruy, Annabelle; Dumat, Camille

    2013-08-01

    Due to diffuse atmospheric fallouts of process particles enriched by metals and metalloids, polluted soils concern large areas at the global scale. Useful tools to assess ecotoxicity induced by these polluted soils are therefore needed. Earthworms are currently used as biotest, however the influence of specie and earthworm behaviour, soil characteristics are poorly highlighted. Our aim was therefore to assess the toxicity of various polluted soils with process particles enriches by metals and metalloids (Pb, Cd, Cu, Zn, As and Sb) collected from a lead recycling facility on two earthworm species belonging to different ecological types and thus likely to have contrasted behavioural responses (Eiseina hortensis and Lumbricus terrestris). The combination of behavioural factors measurements (cast production and biomass) and physico-chemical parameters such as metal absorption, bioaccumulation by earthworms and their localization in invertebrate tissues provided a valuable indication of pollutant bioavailability and ecotoxicity. Soil characteristics influenced ecotoxicity and metal uptake by earthworms, as well as their soil bioturbation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Determination of trace elements and heavy metals in agricultural products cultivated at the Rimac river valley in Lima city using nuclear and related analytical techniques

    OpenAIRE

    Bedregal, Patricia; Torres, Blanca; Olivera, Paula; Mendoza, Pablo; Ubillús, Marco; Creed-Kanashiro, H.; Penny, M.; Junco, J.; Ganoza, L.

    2004-01-01

    There are strong indications that the Rimac river valley is being contaminated with heavy metals and an excess of trace elements that come from some industrial and mining activities developed along the Rimac river valley. The agricultural products cultivated there in could be suffering the same effect. Nuclear and related analytical techniques will play an important role in the study of pollution by providing information concerning the degree of contamination in some agricultural products cul...

  1. Chemical evolution of the solar neighborhood. II. The age-metallicity relation and the history of star formation in the galactic disk

    International Nuclear Information System (INIS)

    Twarog, B.A.

    1980-01-01

    The age-metallicty relation for the disk in the neighborhood of the Sun is derived from four-color and Hβ photometry of a large sample of southern F dwarfs, analyzed in combination with theoretical isochrones. It is found that the mean metallicity of the disk increased by about a factor of 5 between 12 and 5 billion years ago and has increased only slightly since then; this conclusion is independent of the helium abundance assumed for the models

  2. Surprising abundance of Gallionella-related iron oxidizers in creek sediments at pH 4.4 or at high heavy metal concentrations

    Science.gov (United States)

    Fabisch, Maria; Beulig, Felix; Akob, Denise M.; Küsel, Kirsten

    2013-01-01

    We identified and quantified abundant iron-oxidizing bacteria (FeOB) at three iron-rich, metal-contaminated creek sites with increasing sediment pH from extremely acidic (R1, pH 2.7), to moderately acidic (R2, pH 4.4), to slightly acidic (R3, pH 6.3) in a former uranium-mining district. The geochemical parameters showed little variations over the 1.5 year study period. The highest metal concentrations found in creek sediments always coincided with the lowest metal concentrations in creek water at the slightly acidic site R3. Sequential extractions of R3 sediment revealed large portions of heavy metals (Ni, Cu, Zn, Pb, U) bound to the iron oxide fraction. Light microscopy of glass slides exposed in creeks detected twisted stalks characteristic of microaerobic FeOB of the family Gallionellaceae at R3 but also at the acidic site R2. Sequences related to FeOB such as Gallionella ferruginea, Sideroxydans sp. CL21, Ferritrophicum radicicola, and Acidovorax sp. BrG1 were identified in the sediments. The highest fraction of clone sequences similar to the acidophilic “Ferrovum myxofaciens” was detected in R1. Quantitative PCR using primer sets specific for Gallionella spp., Sideroxydans spp., and “Ferrovum myxofaciens” revealed that ~72% (R2 sediment) and 37% (R3 sediment) of total bacterial 16S rRNA gene copies could be assigned to groups of FeOB with dominance of microaerobic Gallionella spp. at both sites. Gallionella spp. had similar and very high absolute and relative gene copy numbers in both sediment communities. Thus, Gallionella-like organisms appear to exhibit a greater acid and metal tolerance than shown before. Microaerobic FeOB from R3 creek sediment enriched in newly developed metal gradient tubes tolerated metal concentrations of 35 mM Co, 24 mM Ni, and 1.3 mM Cd, higher than those in sediments. Our results will extend the limited knowledge of FeOB at contaminated, moderately to slightly acidic environments.

  3. Surprising abundance of Gallionella-related iron oxidizers in creek sediments at pH 4.4 or at high heavy metal concentrations

    Directory of Open Access Journals (Sweden)

    Maria eFabisch

    2013-12-01

    Full Text Available We identified and quantified abundant iron-oxidizing bacteria (FeOB at three iron-rich, metal-contaminated creek sites with increasing sediment pH from extremely acidic (R1, pH 2.7, to moderately acidic (R2, pH 4.4, to slightly acidic (R3, pH 6.3 in a former uranium-mining district. The geochemical parameters showed little variations over the 1.5 year study period. The highest metal concentrations found in creek sediments always coincided with the lowest metal concentrations in creek water at the slightly acidic site R3. Sequential extractions of R3 sediment revealed large portions of heavy metals (Ni, Cu, Zn, Pb, U bound to the iron oxide fraction. Light microscopy of glass slides exposed in creeks detected twisted stalks characteristic of microaerobic FeOB of the family Gallionellaceae at R3 but also at the acidic site R2. Sequences related to FeOB such as Gallionella ferruginea, Sideroxydans sp. CL21, Ferritrophicum radicicola, and Acidovorax sp. BrG1 were identified in the sediments. The highest fraction of clone sequences similar to the acidophilic ‘Ferrovum myxofaciens’ was detected in R1. Quantitative PCR using primer sets specific for Gallionella spp., Sideroxydans spp., and ‘Ferrovum myxofaciens’ revealed that approximately 72% (R2 sediment and 37% (R3 sediment of total bacterial 16S rRNA gene copies could be assigned to groups of FeOB with dominance of microaerobic Gallionella spp. at both sites. Gallionella spp. had similar and very high absolute and relative gene copy numbers in both sediment communities. Thus, Gallionella-like organisms appear to exhibit a greater acid and metal tolerance than shown before. Microaerobic FeOB from R3 creek sediment enriched in newly developed metal gradient tubes tolerated metal concentrations of 35 mM Co, 24 mM Ni, and 1.3 mM Cd, higher than those in sediments. Our results will extend the limited knowledge of FeOB at contaminated, moderately to slightly acidic environments.

  4. Separate Ways: The Mass–Metallicity Relation Does Not Strongly Correlate with Star Formation Rate in SDSS-IV MaNGA Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Barrera-Ballesteros, J. K.; Heckman, T. [Department of Physics and Astronomy, Johns Hopkins University, Bloomberg Center, 3400 N. Charles St., Baltimore, MD 21218 (United States); Sánchez, S. F. [Instituto de Astronomía, Universidad Nacional Autónoma de México, A.P. 70-264, 04510 México, D.F., México (Mexico); Blanc, G. A., E-mail: jbarrer3@jhu.edu [Observatories of the Carnegie Institution for Science, 813 Santa Barbara St, Pasadena, CA 91101 (United States); Collaboration: MaNGA Team

    2017-07-20

    We present the integrated stellar mass–metallicity relation (MZR) for more than 1700 galaxies included in the integral field area SDSS-IV MaNGA survey. The spatially resolved data allow us to determine the metallicity at the same physical scale (effective radius, R {sub eff}) using a heterogeneous set of 10 abundance calibrators. In addition to scale factors, the shape of the MZR is similar for all calibrators, consistent with those reported previously using single-fiber and integral field spectroscopy. We compare the residuals of this relation against the star formation rate (SFR) and specific SFR (sSFR). We do not find a strong secondary relation of the MZR with either SFR or sSFR for any of the calibrators, in contrast with previous single-fiber spectroscopic studies. Our results agree with a scenario in which metal enrichment happens at local scales, with global outflows playing a secondary role in shaping the chemistry of galaxies and cold-gas inflows regulating the stellar formation.

  5. Separate Ways: The Mass–Metallicity Relation Does Not Strongly Correlate with Star Formation Rate in SDSS-IV MaNGA Galaxies

    International Nuclear Information System (INIS)

    Barrera-Ballesteros, J. K.; Heckman, T.; Sánchez, S. F.; Blanc, G. A.

    2017-01-01

    We present the integrated stellar mass–metallicity relation (MZR) for more than 1700 galaxies included in the integral field area SDSS-IV MaNGA survey. The spatially resolved data allow us to determine the metallicity at the same physical scale (effective radius, R eff ) using a heterogeneous set of 10 abundance calibrators. In addition to scale factors, the shape of the MZR is similar for all calibrators, consistent with those reported previously using single-fiber and integral field spectroscopy. We compare the residuals of this relation against the star formation rate (SFR) and specific SFR (sSFR). We do not find a strong secondary relation of the MZR with either SFR or sSFR for any of the calibrators, in contrast with previous single-fiber spectroscopic studies. Our results agree with a scenario in which metal enrichment happens at local scales, with global outflows playing a secondary role in shaping the chemistry of galaxies and cold-gas inflows regulating the stellar formation.

  6. Separate Ways: The Mass-Metallicity Relation Does Not Strongly Correlate with Star Formation Rate in SDSS-IV MaNGA Galaxies

    Science.gov (United States)

    Barrera-Ballesteros, J. K.; Sánchez, S. F.; Heckman, T.; Blanc, G. A.; The MaNGA Team

    2017-07-01

    We present the integrated stellar mass-metallicity relation (MZR) for more than 1700 galaxies included in the integral field area SDSS-IV MaNGA survey. The spatially resolved data allow us to determine the metallicity at the same physical scale (effective radius, R eff) using a heterogeneous set of 10 abundance calibrators. In addition to scale factors, the shape of the MZR is similar for all calibrators, consistent with those reported previously using single-fiber and integral field spectroscopy. We compare the residuals of this relation against the star formation rate (SFR) and specific SFR (sSFR). We do not find a strong secondary relation of the MZR with either SFR or sSFR for any of the calibrators, in contrast with previous single-fiber spectroscopic studies. Our results agree with a scenario in which metal enrichment happens at local scales, with global outflows playing a secondary role in shaping the chemistry of galaxies and cold-gas inflows regulating the stellar formation.

  7. Metal ion attachment to the matrix meso-tetrakis(pentafluorophenyl)porphyrin, related matrices and analytes: an experimental and theoretical study.

    Science.gov (United States)

    van Kampen, Jeroen J A; Luider, Theo M; Ruttink, Paul J A; Burgers, Peter C

    2009-11-01

    In a previous study [van Kampen et al. Analytical Chemistry 2006; 78: 5403], we found that meso-tetrakis (pentafluorophenyl)porphyrin (F20TPP), in combination with lithium salts, provides an efficient matrix to cationize small molecules by Li+ attachment and that this combination can be successfully applied to the quantitative analysis of drugs, such as antiretroviral compounds using matrix-assisted laser desorption ionization in conjunction with a time-of-flight analyzer (MALDI-TOF). In the present study, we further explore the mechanism of metal ion attachment to F20TPP and analytes by MALDI-FTMS(/MS). To this end, we have studied the interaction of F20TPP and analytes with various mono-, di- and trivalent metal ions (Li+, Na+, K+, Rb+, Cs+, Co2+, Cu2+, Zn2+, Fe2+, Fe3+ and Ga3+). For the alkali cations, we find that F20TPP forms complexes only with Li+ and Na+; in addition, model analyte molecules such as poly(ethyleneglycol)s, mixed with F20TPP and the alkali cations, also only form Li+ and Na+ adducts. This contrasts sharply with the commonly used matrix 2,5-dihydroxybenzoic acid, where analytes are most efficiently cationized by Na+ or K+. Reasons for this difference are delineated. Ab initio calculations on porphyrin itself reveal that even the smallest alkali cation, Li+, does not fit in the porphyrin cavity, but lies on top of it, pushing the 21H and 23 H hydrogen atoms out of and below the plane with concomitant bending of the porphyrin skeleton in the opposite direction, i.e. toward the cation. Thus, the Li+ ion is not effectively sequestered and is in fact exposed and thus accessible for donation to analyte molecules. Interaction of F20TPP with di- and trivalent metal ions leads to protoporphyrin-metal ions, where the metal ion is captured within the protoporphyrin dianion cavity. The most intense signal is obtained when F20TPP is reacted with CuCl2 and then subjected to laser ablation. This method presents an easy general route to study the metal

  8. Assessment of levels and 'health-effects' of airborne particulate matter in mining, metal refining and metal working industries using nuclear and related analytical techniques

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-01-15

    The International Atomic Energy Agency (IAEA) has been supporting, over the years, several coordinated research programmes (CRPs) on various research topics related to environmental issues impacting human health. A variety of industrial environments such as: galvanisation, iron and steel production, steel construction, coal fired thermal power plants, mining and mineral beneficiation of monazite, zinc smelters, and phosphate fertilizer production plants were included in this CRP. Toxic elements specific for particular industries as potential pollutants were monitored within individual projects. The CRP focussed on the use of nuclear and related analytical techniques for studies of exposure to inorganic constituents and radionuclides from naturally occurring radioactive materials (NORMs), in the workplaces and their impacts on the health of the workers. The objectives were to: develop strategies and techniques for sampling of workplace airborne particulate matter (APM) and of bio-markers (e.g. hair, blood, nails, teeth, urine, breath) of exposed and non-exposed individuals; develop reliable analytical procedures for the analysis of such samples, using nuclear and related analytical techniques; carry out workplace and personal monitoring surveys, and assess workers' exposure to toxic elements on the basis of measurements results. This document provides an overview of the activities performed under the CRP by the participants. The overall achievements are summarized and those aspects that require a further deeper look are also pointed out. The individual country reports include details on the progress made by the respective participants during the CRP period.

  9. GAS REGULATION OF GALAXIES: THE EVOLUTION OF THE COSMIC SPECIFIC STAR FORMATION RATE, THE METALLICITY-MASS-STAR-FORMATION RATE RELATION, AND THE STELLAR CONTENT OF HALOS

    Energy Technology Data Exchange (ETDEWEB)

    Lilly, Simon J.; Carollo, C. Marcella; Pipino, Antonio; Peng Yingjie [Institute for Astronomy, Department of Physics, ETH Zurich, CH-8093 Zurich (Switzerland); Renzini, Alvio [Department of Physics and Astronomy Galileo Galilei, Universita degli Studi di Padova, via Marzolo 8, I-35131 Padova (Italy)

    2013-08-01

    A very simple physical model of galaxies is one in which the formation of stars is instantaneously regulated by the mass of gas in a reservoir with mass loss scaling with the star-formation rate (SFR). This model links together three different aspects of the evolving galaxy population: (1) the cosmic time evolution of the specific star-formation rate (sSFR) relative to the growth of halos, (2) the gas-phase metallicities across the galaxy population and over cosmic time, and (3) the ratio of the stellar to dark matter mass of halos. The gas regulator is defined by the gas consumption timescale ({epsilon}{sup -1}) and the mass loading {lambda} of the wind outflow {lambda}{center_dot}SFR. The simplest regulator, in which {epsilon} and {lambda} are constant, sets the sSFR equal to exactly the specific accretion rate of the galaxy; more realistic situations lead to an sSFR that is perturbed from this precise relation. Because the gas consumption timescale is shorter than the timescale on which the system evolves, the metallicity Z is set primarily by the instantaneous operation of the regulator system rather than by the past history of the system. The metallicity of the gas reservoir depends on {epsilon}, {lambda}, and sSFR, and the regulator system therefore naturally produces a Z(m{sub star}, SFR) relation if {epsilon} and {lambda} depend on the stellar mass m{sub star}. Furthermore, this relation will be the same at all epochs unless the parameters {epsilon} and {lambda} themselves change with time. A so-called fundamental metallicity relation is naturally produced by these conditions. The overall mass-metallicity relation Z(m{sub star}) directly provides the fraction f{sub star}(m{sub star}) of incoming baryons that are being transformed into stars. The observed Z(m{sub star}) relation of Sloan Digital Sky Survey (SDSS) galaxies implies a strong dependence of stellar mass on halo mass that reconciles the different faint-end slopes of the stellar and halo mass

  10. Genetic variation in metallothionein and metal-regulatory transcription factor 1 in relation to urinary cadmium, copper, and zinc

    International Nuclear Information System (INIS)

    Adams, Scott V.; Barrick, Brian; Christopher, Emily P.; Shafer, Martin M.; Makar, Karen W.; Song, Xiaoling; Lampe, Johanna W.; Vilchis, Hugo; Ulery, April; Newcomb, Polly A.

    2015-01-01

    Background: Metallothionein (MT) proteins play critical roles in the physiological handling of both essential (Cu and Zn) and toxic (Cd) metals. MT expression is regulated by metal-regulatory transcription factor 1 (MTF1). Hence, genetic variation in the MT gene family and MTF1 might influence excretion of these metals. Methods: 321 women were recruited in Seattle, WA and Las Cruces, NM and provided demographic information, urine samples for measurement of metal concentrations by mass spectrometry and creatinine, and blood or saliva for extraction of DNA. Forty-one single nucleotide polymorphisms (SNPs) within the MTF1 gene region and the region of chromosome 16 encoding the MT gene family were selected for genotyping in addition to an ancestry informative marker panel. Linear regression was used to estimate the association of SNPs with urinary Cd, Cu, and Zn, adjusted for age, urinary creatinine, smoking history, study site, and ancestry. Results: Minor alleles of rs28366003 and rs10636 near the MT2A gene were associated with lower urinary Cd, Cu, and Zn. Minor alleles of rs8044719 and rs1599823, near MT1A and MT1B, were associated with lower urinary Cd and Zn, respectively. Minor alleles of rs4653329 in MTF1 were associated with lower urinary Cd. Conclusions: These results suggest that genetic variation in the MT gene region and MTF1 influences urinary Cd, Cu, and Zn excretion. - Highlights: • Genetic variation in metallothionein (MT) genes was assessed in two diverse populations. • Single nucleotide polymorphisms (SNPs) in MT genes were associated with mean urinary Cd, Cu and Zn. • Genetic variation may influence biomarkers of exposure, and associations of exposure with health.

  11. Genetic variation in metallothionein and metal-regulatory transcription factor 1 in relation to urinary cadmium, copper, and zinc

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Scott V., E-mail: sadams@fhcrc.org [Public Health Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109 (United States); Barrick, Brian [Department of Plant and Environmental Sciences, New Mexico State University, Box 30003 MSC 3Q, Las Cruces, NM 88003 (United States); Christopher, Emily P. [Public Health Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109 (United States); Shafer, Martin M. [Environmental Chemistry and Technology, Wisconsin State Laboratory of Hygiene, University of Wisconsin, 2601 Agriculture Dr., Madison, WI 53718 (United States); Makar, Karen W.; Song, Xiaoling [Public Health Science Biomarker Laboratory, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109 (United States); Lampe, Johanna W. [Public Health Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109 (United States); Vilchis, Hugo [Border Epidemiology and Environmental Health Center, New Mexico State University, Box 30001 MSC 3BEC, Las Cruces, NM 88003 (United States); Ulery, April [Department of Plant and Environmental Sciences, New Mexico State University, Box 30003 MSC 3Q, Las Cruces, NM 88003 (United States); Newcomb, Polly A. [Public Health Sciences Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109 (United States)

    2015-12-15

    Background: Metallothionein (MT) proteins play critical roles in the physiological handling of both essential (Cu and Zn) and toxic (Cd) metals. MT expression is regulated by metal-regulatory transcription factor 1 (MTF1). Hence, genetic variation in the MT gene family and MTF1 might influence excretion of these metals. Methods: 321 women were recruited in Seattle, WA and Las Cruces, NM and provided demographic information, urine samples for measurement of metal concentrations by mass spectrometry and creatinine, and blood or saliva for extraction of DNA. Forty-one single nucleotide polymorphisms (SNPs) within the MTF1 gene region and the region of chromosome 16 encoding the MT gene family were selected for genotyping in addition to an ancestry informative marker panel. Linear regression was used to estimate the association of SNPs with urinary Cd, Cu, and Zn, adjusted for age, urinary creatinine, smoking history, study site, and ancestry. Results: Minor alleles of rs28366003 and rs10636 near the MT2A gene were associated with lower urinary Cd, Cu, and Zn. Minor alleles of rs8044719 and rs1599823, near MT1A and MT1B, were associated with lower urinary Cd and Zn, respectively. Minor alleles of rs4653329 in MTF1 were associated with lower urinary Cd. Conclusions: These results suggest that genetic variation in the MT gene region and MTF1 influences urinary Cd, Cu, and Zn excretion. - Highlights: • Genetic variation in metallothionein (MT) genes was assessed in two diverse populations. • Single nucleotide polymorphisms (SNPs) in MT genes were associated with mean urinary Cd, Cu and Zn. • Genetic variation may influence biomarkers of exposure, and associations of exposure with health.

  12. EVALUATION OF FERRIC CHLORIDE AND ALUM EFFICIENCIES IN ENHANCED COAGULATION FOR TOC REMOVAL AND RELATED RESIDUAL METAL CONCENTRATIONS

    Directory of Open Access Journals (Sweden)

    A. Mesdaghinia, M. T. Rafiee, F. Vaezi and A. H. Mahvi

    2005-07-01

    Full Text Available Although the removal of colloidal particles continues to be an important reason for using coagulation, a newer objective, the removal of natural organic matter (NOM to reduce the formation of disinfection by-products (DBPs, is growing in importance. Enhanced coagulation is thus introduced to most water utilities treating surface water. Bench-scale experiments were conducted to compare the effectiveness of alum and ferric chloride in removing DBPs precursors from eight synthetic water samples, each representing a different element of the USEPA’s 3×3 enhanced coagulation matrix. The effect of enhanced coagulation on the residual metal (aluminum/iron concentration in the treated water was assessed as well. The removal of total organic carbon (TOC was dependent on the coagulant type and was enhanced with increasing coagulant dose, but the latter had no further considerable effect in case of increasing to high levels. For all the treated samples coagulation with ferric chloride proved to be more effective than alum at similar doses and the mean values of treatment efficiencies were 51% and 32% for ferric chloride and alum, respectively. Ferric chloride was therefore considered the better chemical for enhancing the coagulation process. Besides, due to less production of sludge by this coagulant, it would be predicted that treatment plants would be confronted to fewer problems with respect to final sludge disposal. Measurements of residual metal in treated water indicated that iron and aluminum concentrations had been increased as expected but the quality of water concerning the residual metal deteriorated much more in cases of under-dosing. Despite expecting high residual Al and Fe concentrations under enhanced coagulation, metal concentrations were frequently remained low and were not increased appreciably.

  13. Loss of metal ions, disulfide reduction and mutations related to familial ALS promote formation of amyloid-like aggregates from superoxide dismutase.

    Directory of Open Access Journals (Sweden)

    Zeynep A Oztug Durer

    Full Text Available Mutations in the gene encoding Cu-Zn superoxide dismutase (SOD1 are one of the causes of familial amyotrophic lateral sclerosis (FALS. Fibrillar inclusions containing SOD1 and SOD1 inclusions that bind the amyloid-specific dye thioflavin S have been found in neurons of transgenic mice expressing mutant SOD1. Therefore, the formation of amyloid fibrils from human SOD1 was investigated. When agitated at acidic pH in the presence of low concentrations of guanidine or acetonitrile, metalated SOD1 formed fibrillar material which bound both thioflavin T and Congo red and had circular dichroism and infrared spectra characteristic of amyloid. While metalated SOD1 did not form amyloid-like aggregates at neutral pH, either removing metals from SOD1 with its intramolecular disulfide bond intact or reducing the intramolecular disulfide bond of metalated SOD1 was sufficient to promote formation of these aggregates. SOD1 formed amyloid-like aggregates both with and without intermolecular disulfide bonds, depending on the incubation conditions, and a mutant SOD1 lacking free sulfhydryl groups (AS-SOD1 formed amyloid-like aggregates at neutral pH under reducing conditions. ALS mutations enhanced the ability of disulfide-reduced SOD1 to form amyloid-like aggregates, and apo-AS-SOD1 formed amyloid-like aggregates at pH 7 only when an ALS mutation was also present. These results indicate that some mutations related to ALS promote formation of amyloid-like aggregates by facilitating the loss of metals and/or by making the intramolecular disulfide bond more susceptible to reduction, thus allowing the conversion of SOD1 to a form that aggregates to form resembling amyloid. Furthermore, the occurrence of amyloid-like aggregates per se does not depend on forming intermolecular disulfide bonds, and multiple forms of such aggregates can be produced from SOD1.

  14. Application of liquid metals for the extraction of solid metals

    International Nuclear Information System (INIS)

    Borgstedt, H.U.

    1996-01-01

    Liquid metals dissolve several solid metals in considerable amounts at moderate temperatures. The dissolution processes may be based upon simple physical solubility, formation of intermetallic phases. Even chemical reactions are often observed in which non-metallic elements might be involved. Thus, the capacity to dissolve metals and chemical properties of the liquid metals play a role in these processes. Besides the solubility also chemical properties and thermochemical data are of importance. The dissolution of metals in liquid metals can be applied to separate the solutes from other metals or non-metallic phases. Relatively noble metals can be chemically reduced by the liquid phases. Such solution processes can be applied in the extractive metallurgy, for instance to extract metals from metallic waste. The recycling of metals is of high economical and ecological importance. Examples of possible processes are discussed. (author)

  15. Ferromagnetism and suppression of metallic clusters in Fe implanted ZnO -- a phenomenon related to defects?

    International Nuclear Information System (INIS)

    Arenholz, Elke; Zhou, S.; Potzger, K.; Talut, G.; Reuther, H.; Kuepper, K.; Grenzer, J.; Xu, Q.; Mucklich, A.; Helm, M.; Fassbender, J.; Arenholz, E.

    2008-01-01

    We investigated ZnO(0001) single crystals annealed in high vacuum with respect to their magnetic properties and cluster formation tendency after implant-doping with Fe. While metallic Fe cluster formation is suppressed, no evidence for the relevance of the Fe magnetic moment to the observed ferromagnetism was found. The latter along with the cluster suppression is discussed with respect to defects in the ZnO host matrix, since the crystalline quality of the substrates was lowered due to the preparation as observed by x-ray diffraction

  16. Ferromagnetism and suppression of metallic clusters in Fe implanted ZnO: a phenomenon related to defects?

    International Nuclear Information System (INIS)

    Zhou Shengqiang; Potzger, K; Talut, G; Reuther, H; Kuepper, K; Grenzer, J; Xu Qingyu; Muecklich, A; Helm, M; Fassbender, J; Arenholz, E

    2008-01-01

    We investigated ZnO(0 0 0 1) single crystals annealed in high vacuum with respect to their magnetic properties and cluster formation tendency after implant-doping with Fe. While metallic Fe cluster formation is suppressed, no evidence for the relevance of the Fe magnetic moment to the observed ferromagnetism was found. The latter along with the cluster suppression is discussed with respect to defects in the ZnO host matrix, since the crystalline quality of the substrates was lowered due to the preparation as observed by x-ray diffraction

  17. Fungitoxicity of metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Somers, E

    1961-01-01

    The in vitro fungistatic activity of some twenty-four metal cations has been determine against Alternaria tenuis and Botrytis fabae. The metal salts, mainly nitrates, were tested in aqueous solution without added spore germination stimulant. The logarithm of the metal ion concentration at the ED 50 value has been found to conform to the exponenttial relationship with electronegativity proposed by Danielli and Davies (1951). These results are discussed in relation to the site of action of metal cations on the fungal cell.

  18. Catalytic ozonation not relying on hydroxyl radical oxidation: A selective and competitive reaction process related to metal-carboxylate complexes

    KAUST Repository

    Zhang, Tao

    2014-01-01

    Catalytic ozonation following non-hydroxyl radical pathway is an important technique not only to degrade refractory carboxylic-containing organic compounds/matter but also to avoid catalyst deactivation caused by metal-carboxylate complexation. It is unknown whether this process is effective for all carboxylates or selective to special molecule structures. In this work, the selectivity was confirmed using O3/(CuO/CeO2) and six distinct ozone-resistant probe carboxylates (i.e., acetate, citrate, malonate, oxalate, pyruvate and succinate). Among these probe compounds, pyruvate, oxalate, and citrate were readily degraded following the rate order of oxalate>citrate>pyruvate, while the degradation of acetate, malonate, and succinate was not promoted. The selectivity was independent on carboxylate group number of the probe compounds and solution pH. Competitive degradation was observed for carboxylate mixtures following the preference order of citrate, oxalate, and finally pyruvate. The competitive degradation was ascribed to competitive adsorption on the catalyst surface. It was revealed that the catalytically degradable compounds formed bidentate chelating or bridging complexes with surface copper sites of the catalyst, i.e., the active sites. The catalytically undegradable carboxylates formed monodentate complexes with surface copper sites or just electrostatically adsorbed on the catalyst surface. The selectivity, relying on the structure of surface metal-carboxylate complex, should be considered in the design of catalytic ozonation process. © 2013 Elsevier B.V.

  19. Impact of metal and ceramic fixed orthodontic appliances on judgments of beauty and other face-related attributes.

    Science.gov (United States)

    Fonseca, Lílian Martins; Araújo, Telma Martins de; Santos, Aline Rôde; Faber, Jorge

    2014-02-01

    Physical attributes, behavior, and personal ornaments exert a direct influence on how a person's beauty and personality are judged. The aim of this study was to investigate how people who wear a fixed orthodontic appliance see themselves and are seen by others in social settings. A total of 60 adults evaluated their own smiling faces in 3 different scenarios: without a fixed orthodontic appliance, wearing a metal fixed orthodontic appliance, and wearing an esthetic fixed orthodontic appliance. Furthermore, 15 adult raters randomly assessed the same faces in standardized front-view facial photographs. Both the subjects and the raters answered a questionnaire in which they evaluated criteria on a numbered scale ranging from 0 to 10. The models judged their own beauty, and the raters assigned scores to beauty, age, intelligence, ridiculousness, extroversion, and success. The self-evaluations showed decreased beauty scores (P <0.0001) when a fixed orthodontic appliance, especially a metal one, was being worn. There was no statistically significant difference between the 3 situations in the 6 criteria analyzed. A fixed orthodontic appliance did not affect how personal attributes are assessed. However, fixed orthodontic appliances apparently changed the subjects' self-perceptions when they looked in the mirror. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  20. A framework and methods for incorporating gender-related issues in wildlife risk assessment: gender-related differences in metal levels and other contaminants as a case study.

    Science.gov (United States)

    Burger, Joanna

    2007-05-01

    Gender plays a role in the genetics, physiology, morphology, and behavior of organisms, and thus influences the uptake, fate, and effects of contaminants in organisms. There are a number of chemical analysis tools, as well as biological approaches to understanding the influence of gender on contaminant levels and effects in wildlife. Biological approaches occur at all levels, from mutagenesis, gene expression and biochemistry, to physiology, morphology and development, to pathology and behavior. Information on the effects of gender at all these levels is essential for model building, risk assessment, and developing biomonitoring plans. Gender influences both internal and external fate and effects. However, bioaccumulation and effects cannot occur without exposure, which is mediated by behavior, bioavailability, bioaccessibility, and absorption. Gender influences a number of individual features (size, nutrition, genetics, hormones), that in turn affect niche differentiation, leading back to differences in exposure and susceptibility. Both sexes have a variety of methods of ridding the body of contaminants, through the bile, urine, exhaled air, and sloughing of epidermal structures (skin, hair, feathers). Females can also rid their body of contaminants through egg contents and egg shells, or mammals by transfer to the developing fetus and through breast milk. The availability of contaminant data in wildlife depends partly on the ease of identification of the sexes by either external or internal examination. Thus, there are more data on contaminant levels in birds and mammals than in fish. Surprisingly, metal levels are not uniformly low in females, even when they are morphologically smaller than males. For 43 studies of metals in vertebrates, females had higher levels in 30 cases where there were significant differences (and males were higher in only 14 cases). Females usually had higher levels of mercury than males. Review of the literature suggests that authors

  1. Metal-metal-hofteproteser

    DEFF Research Database (Denmark)

    Ulrich, Michael; Overgaard, Søren; Penny, Jeannette

    2014-01-01

    In Denmark 4,456 metal-on-metal (MoM) hip prostheses have been implanted. Evidence demonstrates that some patients develope adverse biological reactions causing failures of MoM hip arthroplasty. Some reactions might be systemic. Failure rates are associated with the type and the design of the Mo...

  2. Chemical characteristics of dissolved organic matter (DOM) in relation to heavy metal concentrations in soil water from boreal peatlands after clear-cut harvesting

    Science.gov (United States)

    Kiikkilä, O.; Nieminen, T.; Starr, M.; Ukonmaanaho, L.

    2012-04-01

    Boreal peatlands form an important terrestrial carbon reserve and are a major source of dissolved organic matter (DOM) to surface waters, particularly when disturbed through forestry practices such as draining or timber harvesting. Heavy metals show a strong affinity to organic matter and so, along with DOM, heavy metals can be mobilized and transported from the soil to surface waters and sediments where they may become toxic to aquatic organisms and pass up the food chain. The complexation of heavy metals with DOM can be expected to be related and determined by the chemical characteristics of DOM and oxidation/reducing conditions in the peat. We extracted interstitial water from peat samples and determined the concentrations of dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and Al, Cu, Zn and Fe in various fractions of DOM isolated by adsorption properties (XAD-8 fractionation) and molecular-weight (ultrafiltration). The peat samples were taken from 0-30 and 30-50 cm depth in drained peatland catchments two years after whole-tree or stem-only clear-cut harvesting (Scots pine or Norway spruce) had been carried out. The samples from the upper layer had been subject to alternating saturation/aeration conditions while the deeper layer had been continuously under the water table. The fractionation of DOC and DON according to both adsorption properties and molecular-weight fractions clearly differed between the upper and lower peat layers. While the hydrophobic acid fraction contained proportionally more DOC and DON than the hydrophilic acid fraction in the upper peat layer the results were vice versa in the lower peat layer. High-molecular-weight compounds (> 100 kDa) were proportionally more abundant in the upper and low-molecular-weight compounds (< 1 kDa) in the lower peat layer. These differences are assumed to reflect differences in the aerobic/ anaerobic conditions and degree of decomposition between the two layers. The concentrations of Zn, Al

  3. Nature of low dimensional structural modulations and relative phase stability in RexMo(W)1-xS2 transition metal dichalcogenide alloys

    KAUST Repository

    Sahu, R.

    2017-03-08

    We report on the various types of Peierls like two dimensional structural modulations and relative phase stability of 2H and 1T poly-types in the RexMo1-xS2 and RexW1-xS2 alloy system. Theoretical calculation predicts a polytype phase transition cross over at ∼50 at. % of Mo and W in ReS2 in both monolayer and bulk form, respectively. Experimentally, two different types of structural modulations at 50% and a modulation corresponding to trimerization at 75% alloy composition are observed for RexMo1-xS2 and only one type of modulation is observed at the 50% RexW1-xS2 alloy system. The 50% alloy system is found to be a suitable monolithic candidate for metal semiconductor transition with minute external perturbation. ReS2 is known to be in the 2D Peierls distorted 1Td structure and forms a chain like superstructure. Incorporation of Mo and W atoms into the ReS2 lattice modifies the metal-metal hybridization between the cations and influences the structural modulation and electronic properties of the system. The results offer yet another effective way to tune the electronic structure and poly-type phases of this class of materials other than intercalation, strain, and vertical stacking arrangement.

  4. Atomic-Scale Origin of the Quasi-One-Dimensional Metallic Conductivity in Strontium Niobates with Perovskite-Related Layered Structures.

    Science.gov (United States)

    Chen, Chunlin; Yin, Deqiang; Inoue, Kazutoshi; Lichtenberg, Frank; Ma, Xiuliang; Ikuhara, Yuichi; Bednorz, Johannes Georg

    2017-12-26

    The quasi-one-dimensional (1D) metallic conductivity of the perovskite-related Sr n Nb n O 3n+2 compounds is of continuing fundamental physical interest as well as being important for developing advanced electronic devices. The Sr n Nb n O 3n+2 compounds can be derived by introducing additional oxygen into the SrNbO 3 perovskite. However, the physical origin for the transition of electrical properties from the three-dimensional (3D) isotropic conductivity in SrNbO 3 to the quasi-1D metallic conductivity in Sr n Nb n O 3n+2 requires more in-depth clarification. Here we combine advanced transmission electron microscopy with atomistic first-principles calculations to unambiguously determine the atomic and electronic structures of the Sr n Nb n O 3n+2 compounds and reveal the underlying mechanism for their quasi-1D metallic conductivity. We demonstrate that the local electrical conductivity in the Sr n Nb n O 3n+2 compounds directly depends on the configuration of the NbO 6 octahedra in local regions. These findings will shed light on the realization of two-dimensional (2D) electrical conductivity from a bulk material, namely by segmenting a 3D conductor into a stack of 2D conducting thin layers.

  5. Determination of selected metals in urban runoff and related estuarine sediments by neutron activation and atomic absorption

    International Nuclear Information System (INIS)

    Christensen, E.R.; Guinn, V.P.; Scherfig, J.

    1977-01-01

    Pollution sources for Newport Bay, California are of a nonpoint nature. To assess the heavy metals loading of the runoff into the Bay, 18 water samples, taken during dry and rainy periods, have been analyzed for Mn, Cu, Zn, and Pb, using atomic absorption spectrometry (AAS). In addition, 7 sediment cores from the Upper Bay and 5 sediment grab samples from the Lower Bay were analyzed for Cr, Mn, Fe, Co, Cu, Zn, and Pb. Instrumental neutron activation analysis (INAA) was used for Cr, Fe, and Co, whereas Mn, Cu, and Pb were determined by AAS. Zinc was determined by both of these techniques. Three major streams pass into Newport Bay carrying: (1) agricultural and to some extent urban and residential runoff (70-90%), (2) urban runoff (10-30%), and (3) residential runoff (<5%). The levels of Zn and Pb are much higher under storm conditions, e.g., 338 μg/l Zn and 425 μg/l Pb, than during dry weather, where typical concentrations are 20 μg/l Zn and 9 μg/l Pb. For Cu there is a moderate increase from about 10 μg/l in dry weather to a maximum of 54 μg/l under storm conditions. Soil erosion appears to be responsible for high Mn values (max. 1230 μg/l) in agricultural storm runoff. The cleansing action of a storm is evidenced by high concentrations in the beginning, and much lower levels towards the end of the storm.Vertical profiles of heavy metals in sediment cores indicate that Zn and Pb are the only metals of those investigated that show clearly increased levels in the uppermost layers. Typical enrichment ratios are 2.0 for Zn and 5.5 for Pb. Maximum concentrations of Zn and Pb in sediments from the Upper Bay were 300 ppm and 132 ppm, respectively. The highest Pb value was found close to the mouth of the urban drainage channel. Dating of selected cores was carried out by the Pb-210 method. Mass injection rates into Upper Newport Bay for Zn and Pb of anthropogenic origin were estimated to be 6.0 and 6.5 tons/yr, respectively

  6. Metallated metal-organic frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Bury, Wojciech; Farha, Omar K.; Hupp, Joseph T.; Mondloch, Joseph E.

    2017-08-22

    Porous metal-organic frameworks (MOFs) and metallated porous MOFs are provided. Also provided are methods of metallating porous MOFs using atomic layer deposition and methods of using the metallated MOFs as catalysts and in remediation applications.

  7. Relation between calculated Lennard-Jones potential and thermal stability of Cu-based bulk metallic glasses

    International Nuclear Information System (INIS)

    Lin, T.; Bian, X.F.; Jiang, J.

    2006-01-01

    Two metallic bulk glasses, Cu 60 Zr 30 Ti 10 and Cu 47 Ti 33 Zr 11 Ni 8 Si 1 , with a diameter of 3 mm were prepared by copper mold casting method. Dilatometric measurement was carried out on the two glassy alloys to obtain information about the average nearest-neighbour distance r 0 and the effective depth of pair potential V 0 . By assuming a Lennard-Jones potential, r 0 and V 0 were calculated to be 0.28 nm and 0.16 eV for Cu 60 Zr 30 Ti 10 and 0.27 nm and 0.13 eV for Cu 47 Ti 33 Zr 11 Ni 8 Si 1 , respectively. It was found that the glassy alloy Cu 60 Zr 30 Ti 10 was more stable than Cu 47 Ti 33 Zr 11 Ni 8 Si 1 against heating from both experiment and calculation

  8. CoCr wear particles generated from CoCr alloy metal-on-metal hip replacements, and cobalt ions stimulate apoptosis and expression of general toxicology-related genes in monocyte-like U937 cells

    Energy Technology Data Exchange (ETDEWEB)

    Posada, Olga M., E-mail: O.M.PosadaEstefan@leeds.ac.uk [Biomedical Engineering Department, University of Strathclyde, Wolfson Centre, Glasgow G4 0NW (United Kingdom); Gilmour, Denise [Pure and Applied Chemistry Department, University of Strathclyde, Thomas Graham Building, Glasgow G1 1XL (United Kingdom); Tate, Rothwelle J., E-mail: r.j.tate@strath.ac.uk [Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE (United Kingdom); Grant, M. Helen [Biomedical Engineering Department, University of Strathclyde, Wolfson Centre, Glasgow G4 0NW (United Kingdom)

    2014-11-15

    Cobalt-chromium (CoCr) particles in the nanometre size range and their concomitant release of Co and Cr ions into the patients' circulation are produced by wear at the articulating surfaces of metal-on-metal (MoM) implants. This process is associated with inflammation, bone loss and implant loosening and led to the withdrawal from the market of the DePuy ASR™ MoM hip replacements in 2010. Ions released from CoCr particles derived from a resurfacing implant in vitro and their subsequent cellular up-take were measured by ICP-MS. Moreover, the ability of such metal debris and Co ions to induce both apoptosis was evaluated with both FACS and immunoblotting. qRT-PCR was used to assess the effects on the expression of lymphotoxin alpha (LTA), BCL2-associated athanogene (BAG1), nitric oxide synthase 2 inducible (NOS2), FBJ murine osteosarcoma viral oncogene homolog (FOS), growth arrest and DNA-damage-inducible alpha (GADD45A). ICP-MS showed that the wear debris released significant (p < 0.05) amounts of Co and Cr ions into the culture medium, and significant (p < 0.05) cellular uptake of both ions. There was also an increase (p < 0.05) in apoptosis after a 48 h exposure to wear debris. Analysis of qRT-PCR results found significant up-regulation (p < 0.05) particularly of NOS2 and BAG1 in Co pre-treated cells which were subsequently exposed to Co ions + debris. Metal debris was more effective as an inducer of apoptosis and gene expression when cells had been pre-treated with Co ions. This suggests that if a patient receives sequential bilateral CoCr implants, the second implant may be more likely to produce adverse effects than the first one. - Highlights: • Effects of CoCr nanoparticles and Co ions on U937 cells were investigated. • Ions released from wear debris play an important role in cellular response, • Toxicity of Co ions could be related to NO metabolic processes and apoptosis. • CoCr particles were a more effective inducer of apoptosis after cell

  9. Cadmium bound to metal rich granules and exoskeleton from Gammarus pulex causes increased gut lipid peroxidation in zebrafish following single dietary exposure

    Energy Technology Data Exchange (ETDEWEB)

    Khan, F.R., E-mail: fkhan@wlu.ca [Nutritional Sciences Division, King' s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH (United Kingdom); Bury, N.R.; Hogstrand, C. [Nutritional Sciences Division, King' s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH (United Kingdom)

    2010-01-31

    There has been a growing interest in establishing how the sub-cellular distribution of metals in macro-invertebrate prey affects metal trophic bioavailability and toxicity. In this study, the crustacean Gammarus pulex was exposed to 300 {mu}g Cd l{sup -1} spiked with {sup 109}Cd for 13 days, from which the two principal metal containing sub-cellular fractions, the metallothionein-like protein (MTLP) and the metal rich granule and exoskeleton (MRG + exo) were isolated. These fractions were produced at equal metal content, incorporated into gelatin and fed to zebrafish as a single meal; assimilation efficiency (AE), carcass and gut tissue metal concentrations and gut lipid peroxidative damage measured as malondialdehyde (MDA) were assessed. The AE of cadmium bound to the MTLP fraction was 32.1 {+-} 5.6% which was significantly greater than the AE of MRG + exo bound Cd, 13.0 {+-} 2.1% (p < 0.05). Of the metal retained by the fish at 72 h post-feeding, 94% of MTLP-Cd had been incorporated into the carcass, whereas a significant proportion (46%) of MRG + exo-Cd, although assimilated, appeared to remain associated with intestinal tissue. However, this did not translate into a gut tissue concentration difference with 6.8 {+-} 1.2 ng Cd g{sup -1} in fish fed MTLP-Cd compared to 9.5 {+-} 1.4 ng Cd g{sup -1} in fish fed MRG + exo fraction. Both feeds led to significantly increased MDA levels compared to the control group (gelatin only feed), but MRG + exo feed caused significantly more oxidative damage than the MTLP feed (p < 0.01). Thus, MTLP-Cd is more bioavailable than the cadmium bound to granules and exoskeleton, but it was the latter fraction, largely considered as having limited bioavailability, that appeared to exert a greater localised oxidative injury to the digestive tract of zebrafish.

  10. The FMOS-COSMOS survey of star-forming galaxies at z ∼ 1.6. II. The mass-metallicity relation and the dependence on star formation rate and dust extinction

    Energy Technology Data Exchange (ETDEWEB)

    Zahid, H. J.; Sanders, D. B.; Chu, J.; Hasinger, G. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Kashino, D. [Division of Particle and Astrophysical Science, Graduate School of Science, Nagoya University, Nagoya, 464-8602 (Japan); Silverman, J. D. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, the University of Tokyo, Kashiwanoha, Kashiwa, 277-8583 (Japan); Kewley, L. J. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Daddi, E. [CEA-Saclay, Service d' Astrophysique, F-91191 Gif-sur-Yvette (France); Renzini, A. [INAF Osservatorio Astronomico di Padova, vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Rodighiero, G. [Dipartimento di Astronomia, Università di Padova, vicolo dell Osservatorio 3, I-35122 Padova (Italy); Nagao, T. [The Hakubi Center for Advanced Research, Kyoto University, Kyoto 606-8302 (Japan); Arimoto, N. [National Astronomical Observatory of Japan, Subaru Telescope, 650 North Aohoku Place, Hilo, HI 96720 (United States); Kartaltepe, J. [National Optical Astronomy Observatory, 950 N. Cherry Ave., Tucson, AZ 85719 (United States); Lilly, S. J.; Carollo, C. M. [Institute for Astronomy, ETH Zürich, Wolfgang-Pauli-strasse 27, 8093 Zürich (Switzerland); Maier, C. [Vienna University, Department of Astrophysics, Tuerkenschanzstrasse 17, 1180 Vienna (Austria); Geller, M. J. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Capak, P. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Ilbert, O. [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, 13388, Marseille (France); Kajisawa, M., E-mail: jabran@ifa.hawaii.edu [Research Center for Space and Cosmic Evolution, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577 (Japan); Collaboration: COSMOS Team; and others

    2014-09-01

    We investigate the relationships between stellar mass, gas-phase oxygen abundance (metallicity), star formation rate (SFR), and dust content of star-forming galaxies at z ∼ 1.6 using Subaru/FMOS spectroscopy in the COSMOS field. The mass-metallicity (MZ) relation at z ∼ 1.6 is steeper than the relation observed in the local universe. The steeper MZ relation at z ∼ 1.6 is mainly due to evolution in the stellar mass where the MZ relation begins to turnover and flatten. This turnover mass is 1.2 dex larger at z ∼ 1.6. The most massive galaxies at z ∼ 1.6 (∼10{sup 11} M {sub ☉}) are enriched to the level observed in massive galaxies in the local universe. The MZ relation we measure at z ∼ 1.6 supports the suggestion of an empirical upper metallicity limit that does not significantly evolve with redshift. We find an anti-correlation between metallicity and SFR for galaxies at a fixed stellar mass at z ∼ 1.6, which is similar to trends observed in the local universe. We do not find a relation between stellar mass, metallicity, and SFR that is independent of redshift; rather, our data suggest that there is redshift evolution in this relation. We examine the relation between stellar mass, metallicity, and dust extinction, and find that at a fixed stellar mass, dustier galaxies tend to be more metal rich. From examination of the stellar masses, metallicities, SFRs, and dust extinctions, we conclude that stellar mass is most closely related to dust extinction.

  11. Active galactic nuclei emission line diagnostics and the mass-metallicity relation up to redshift z ∼ 2: The impact of selection effects and evolution

    International Nuclear Information System (INIS)

    Juneau, Stéphanie; Bournaud, Frédéric; Daddi, Emanuele; Elbaz, David; Duc, Pierre-Alain; Gobat, Raphael; Jean-Baptiste, Ingrid; Le Floc'h, Émeric; Pannella, Maurilio; Schreiber, Corentin; Charlot, Stéphane; Lehnert, M. D.; Pacifici, Camilla; Trump, Jonathan R.; Brinchmann, Jarle; Dickinson, Mark

    2014-01-01

    Emission line diagnostic diagrams probing the ionization sources in galaxies, such as the Baldwin-Phillips-Terlevich (BPT) diagram, have been used extensively to distinguish active galactic nuclei (AGN) from purely star-forming galaxies. However, they remain poorly understood at higher redshifts. We shed light on this issue with an empirical approach based on a z ∼ 0 reference sample built from ∼300,000 Sloan Digital Sky Survey galaxies, from which we mimic selection effects due to typical emission line detection limits at higher redshift. We combine this low-redshift reference sample with a simple prescription for luminosity evolution of the global galaxy population to predict the loci of high-redshift galaxies on the BPT and Mass-Excitation (MEx) diagnostic diagrams. The predicted bivariate distributions agree remarkably well with direct observations of galaxies out to z ∼ 1.5, including the observed stellar mass-metallicity (MZ) relation evolution. As a result, we infer that high-redshift star-forming galaxies are consistent with having normal interstellar medium (ISM) properties out to z ∼ 1.5, after accounting for selection effects and line luminosity evolution. Namely, their optical line ratios and gas-phase metallicities are comparable to that of low-redshift galaxies with equivalent emission-line luminosities. In contrast, AGN narrow-line regions may show a shift toward lower metallicities at higher redshift. While a physical evolution of the ISM conditions is not ruled out for purely star-forming galaxies and may be more important starting at z ≳ 2, we find that reliably quantifying this evolution is hindered by selections effects. The recipes provided here may serve as a basis for future studies toward this goal. Code to predict the loci of galaxies on the BPT and MEx diagnostic diagrams and the MZ relation as a function of emission line luminosity limits is made publicly available.

  12. Active galactic nuclei emission line diagnostics and the mass-metallicity relation up to redshift z ∼ 2: The impact of selection effects and evolution

    Energy Technology Data Exchange (ETDEWEB)

    Juneau, Stéphanie; Bournaud, Frédéric; Daddi, Emanuele; Elbaz, David; Duc, Pierre-Alain; Gobat, Raphael; Jean-Baptiste, Ingrid; Le Floc' h, Émeric; Pannella, Maurilio; Schreiber, Corentin [CEA-Saclay, DSM/IRFU/SAp, F-91191 Gif-sur-Yvette (France); Charlot, Stéphane; Lehnert, M. D.; Pacifici, Camilla [UPMC-CNRS, UMR 7095, Institut d' Astrophysique de Paris, F-75014 Paris (France); Trump, Jonathan R. [University of California Observatories/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Brinchmann, Jarle [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Dickinson, Mark, E-mail: stephanie.juneau@cea.fr [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)

    2014-06-10

    Emission line diagnostic diagrams probing the ionization sources in galaxies, such as the Baldwin-Phillips-Terlevich (BPT) diagram, have been used extensively to distinguish active galactic nuclei (AGN) from purely star-forming galaxies. However, they remain poorly understood at higher redshifts. We shed light on this issue with an empirical approach based on a z ∼ 0 reference sample built from ∼300,000 Sloan Digital Sky Survey galaxies, from which we mimic selection effects due to typical emission line detection limits at higher redshift. We combine this low-redshift reference sample with a simple prescription for luminosity evolution of the global galaxy population to predict the loci of high-redshift galaxies on the BPT and Mass-Excitation (MEx) diagnostic diagrams. The predicted bivariate distributions agree remarkably well with direct observations of galaxies out to z ∼ 1.5, including the observed stellar mass-metallicity (MZ) relation evolution. As a result, we infer that high-redshift star-forming galaxies are consistent with having normal interstellar medium (ISM) properties out to z ∼ 1.5, after accounting for selection effects and line luminosity evolution. Namely, their optical line ratios and gas-phase metallicities are comparable to that of low-redshift galaxies with equivalent emission-line luminosities. In contrast, AGN narrow-line regions may show a shift toward lower metallicities at higher redshift. While a physical evolution of the ISM conditions is not ruled out for purely star-forming galaxies and may be more important starting at z ≳ 2, we find that reliably quantifying this evolution is hindered by selections effects. The recipes provided here may serve as a basis for future studies toward this goal. Code to predict the loci of galaxies on the BPT and MEx diagnostic diagrams and the MZ relation as a function of emission line luminosity limits is made publicly available.

  13. Preliminary investigations on picoplankton-related precipitation of alkaline-earth metal carbonates in meso-oligotrophic lake Geneva (Switzerland

    Directory of Open Access Journals (Sweden)

    Jean-Michel Jaquet

    2013-10-01

    Full Text Available In the course of a routine water-quality survey in meso-oligotrophic lake Geneva (Switzerland, suspended matter was collected by filtration on 0.2 μm membranes in July and August 2012 at the depth of maximal chlorophyll a (Chl a concentration (2 mg m–3. Examination by scanning electron microscopy revealed the presence of numerous dark and gelatinous patches occluding the pores of the membranes, containing high numbers of picoplanktonic cells and, in places, clusters of high-reflectance smooth microspheres (1-2 μm in diameter. Their chemical composition, determined by semi-quantitative, energy-dispersive X ray spectroscopy (EDS showed magnesium (Mg, calcium (Ca, strontium (Sr and barium (Ba (alkaline earth metals to be the dominant cations. Among the anions, phosphorus (P and carbon (C were present, but only the latter is considered here (as carbonate. The microspheres were subdivided into four types represented in a Ca-Sr-Ba ternary space. All types are confined within a domain bound by Ca>45, Sr<10 and Ba<50 (in mole %. Type I, the most frequent, displays a broad variability in Ba/Ca, even within a given cluster. Types II and III are devoid of Ba, but may incorporate P. Type IV contains only Ca. The Type I composition resembles that of benstonite, a Group IIA carbonate that was recently found as intracellular granules in a cyanobacterium from alkaline lake Alchichica (Mexico.Lake Geneva microspheres are solid, featureless and embedded in a mucilage-looking substance in the vicinity of, but seemingly not inside, picoplanktonic cells morphologically similar to Chlorella and Synechococcus. In summer 2012, the macroscopic physico-chemical conditions in lake Geneva epilimnion were such as to allow precipitation of Ca but not of Sr and Ba carbonates. Favourable conditions did exist, though, in the micro-environment provided by the combination of active picoplankton and a mucilaginous envelope. Further studies are ongoing to investigate the

  14. Variations in gene expression levels in four European zebra mussel, Dreissena polymorpha, populations in relation to metal bioaccumulation: A field study.

    Science.gov (United States)

    Kerambrun, E; Rioult, D; Delahaut, L; Evariste, L; Pain-Devin, S; Auffret, M; Geffard, A; David, E

    2016-12-01

    The present study was performed to validate the suitability of using gene expression in zebra mussels, Dreissena polymorpha, for biomonitoring of freshwater environment. Mussels were collected in four French rivers (Meuse, Moselle, Oise and Vilaine) in spring and autumn. Relative gene expression of 9 candidate genes involved in cellular metabolic activities (Cytochrome-c-oxidase - cox, and ATP synthase - atp), detoxification process (Metallothionein - mt and Glutathion-S-Transferase - gst), oxidative stress (Catalase - cat, Superoxyde Dismutase - sod and Glutathion peroxidase - gpx) and digestive functions (Amylase - amy and Cellulase - ghf) were measured in digestive gland. Metal bioaccumulation in tissues and morphometric parameters were also analyzed to interpret molecular responses. All our results are consistent with different physiological reactions to environmental condition between zebra mussel populations. In spring, the levels of mt, sod, gpx, cat, atp, amy and ghf relative expression were significantly higher in mussels with the lowest metal bioaccumulation (the Meuse) compared to at least one of the other sites. In autumn, this higher expression levels in Meuse River were still observed for gpx, cat, atp and amy. This study has also pointed out different sources of variability in gene expression (individual size, season, trophic resources and origin of mussels) which are inevitable in natural fluctuant environment. This underlines the importance to take them into account in field study to propose a correct interpretation of biomarker responses. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Bayesian importance parameter modeling of misaligned predictors: soil metal measures related to residential history and intellectual disability in children.

    Science.gov (United States)

    Onicescu, Georgiana; Lawson, Andrew B; McDermott, Suzanne; Aelion, C Marjorie; Cai, Bo

    2014-09-01

    In this paper, we propose a novel spatial importance parameter hierarchical logistic regression modeling approach that includes measurement error from misalignment. We apply this model to study the relationship between the estimated concentration of soil metals at the residence of mothers and the development of intellectual disability (ID) in their children. The data consist of monthly computerized claims data about the prenatal experience of pregnant women living in nine areas within South Carolina and insured by Medicaid during January 1, 1996 and December 31, 2001 and the outcome of ID in their children during early childhood. We excluded mother-child pairs if the mother moved to an unknown location during pregnancy. We identified an association of the ID outcome with arsenic (As) and mercury (Hg) concentration in soil during pregnancy, controlling for infant sex, maternal race, mother's age, and gestational weeks at delivery. There is some indication that Hg has a slightly higher importance in the third and fourth months of pregnancy, while As has a more uniform effect over all the months with a suggestion of a slight increase in risk in later months.

  16. THEY MIGHT BE GIANTS: LUMINOSITY CLASS, PLANET OCCURRENCE, AND PLANET-METALLICITY RELATION OF THE COOLEST KEPLER TARGET STARS

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Andrew W.; Hilton, Eric J. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Gaidos, Eric [Department of Geology and Geophysics, University of Hawaii, Honolulu, HI 96822 (United States); Lepine, Sebastien, E-mail: amann@ifa.hawaii.edu [Department of Astrophysics, American Museum of Natural History, New York, NY 10024 (United States)

    2012-07-01

    We estimate the stellar parameters of late K- and early M-type Kepler target stars. We obtain medium-resolution visible spectra of 382 stars with K{sub P} - J > 2 ({approx_equal}K5 and later spectral type). We determine luminosity class by comparing the strength of gravity-sensitive indices (CaH, K I, Ca II, and Na I) to their strength in a sample of stars of known luminosity class. We find that giants constitute 96% {+-} 1% of the bright (K{sub P} < 14) Kepler target stars, and 7% {+-} 3% of dim (K{sub P} > 14) stars, significantly higher than fractions based on the stellar parameters quoted in the Kepler Input Catalog (KIC). The KIC effective temperatures are systematically (110{sup +15}{sub -35} K) higher than temperatures we determine from fitting our spectra to PHOENIX stellar models. Through Monte Carlo simulations of the Kepler exoplanet candidate population, we find a planet occurrence of 0.36 {+-} 0.08 when giant stars are properly removed, somewhat higher than when a KIC log g > 4 criterion is used (0.27 {+-} 0.05). Last, we show that there is no significant difference in g - r color (a probe of metallicity) between late-type Kepler stars with transiting Earth-to-Neptune-size exoplanet candidates and dwarf stars with no detected transits. We show that a previous claimed offset between these two populations is most likely an artifact of including a large number of misidentified giants.

  17. Biomonitoring of heavy metal deposition in the south Ural region: some preliminary results obtained by nuclear and related techniques

    International Nuclear Information System (INIS)

    Frontas'eva, M.V.; Steinnes, E.; Lyapunov, S.M.; Cherchintsev, V.D.; Smirnov, L.I.

    1999-01-01

    The first results are reported from the analysis of feather mosses used to study heavy metal atmospheric deposition in the vicinity of Magnitogorsk, the center of the steel industry in Russia. Moss samples collected at sites 30 km to the north-west of the industry were analyzed by instrumental neutron activation analysis using epithermal neutrons (ENAA), Results for a total of 38 elements are reported, including Pb, Cd, and Cu determined by atomic absorption spectroscopy (AAS). The element concentrations in moss samples from this work are compared with relevant literature data for strongly polluted areas in Central and Northern Europe and background values from Norway obtained by the same biomonitoring technique. The concentrations of Sb in the examined area are the highest ever reported for mosses, and also levels of Fe, Cr, and V are found to be particularly high. A scanning electron microscope connected to an XRF analyzer (SEM-XRF) was used to examine the surface of the moss samples. Photographs of identified iron spherules along with other aerosol particles made at magnification of 3500 to 5000 times and corresponding XRF analyses verifying the nature of typical particles are presented

  18. Interplay of metals and bromine with dioxin-related compounds concentrated in e-waste open burning soil from Agbogbloshie in Accra, Ghana

    International Nuclear Information System (INIS)

    Fujimori, Takashi; Itai, Takaaki; Goto, Akitoshi; Asante, Kwadwo A.; Otsuka, Masanari; Takahashi, Shin; Tanabe, Shinsuke

    2016-01-01

    Open burning of electronic waste (e-waste) releases various metals and organohalogen compounds in the environment. Here we investigated the interplay of metals (Cu, Pb, Zn, Fe, Co, and Sr) and bromine (Br) in the formation of dioxin-related compounds (DRCs), including polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs), as well as non-regulated DRCs such as polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) and their monobrominated PCDD/Fs in soils sampled from open burning e-waste sites at Agbogbloshie in Accra, Ghana. The predominant DRCs were PBDFs, PCDFs, PCDDs, and DL-PCBs. Statistical analyzes, X-ray absorption spectroscopy, and the PCDF/PCDD ratio suggested possible formation paths of PCDD/Fs and DL-PCBs by catalytic behaviors of copper chlorides (CuCl, CuCl_2, and Cu_2(OH)_3Cl) and thermal breakdown of polyvinyl chloride. Predominant formation of brominated furans may be derived from electron transfer from intermediates of PBDE to copper, Cu(II) → Cu(I). Lead chloride also contributed to generate DRCs and may become highly bioaccessible through the open burning of e-waste. The main zinc species (ZnCl_2 and ZnS) suggested a possible relationship to generate DRCs and specific zinc source such as tire burning. Cu, Pb, Zn, and Br contained in various e-wastes, wires/cables, plastics, and tires strongly influenced generation of many DRCs. - Highlights: • Extremely high DRCs were detected from an open burning soil of e-waste. • Predominant DRCs were PBDFs, PCDFs, PCDDs, and DL-PCBs. • Some metals shows good correlation to DRCs by PCA and cluster analysis. • Speciation of Cu, Pb, Zn in residual soil were successfully measured by XAFS. • Electron transfer via Cu(II) → Cu(I) can be important for DRCs formation. - Metals speciation in residual soil after open burning of e-waste may act as a catalyst for formation of dioxin-related compounds.

  19. Metal uptake by homegrown vegetables – The relative importance in human health risk assessments at contaminated sites

    Energy Technology Data Exchange (ETDEWEB)

    Augustsson, Anna L.M., E-mail: anna.augustsson@lnu.se [Department of Biology and Environmental Science, Linnaeus University, SE-391 82 Kalmar (Sweden); Uddh-Söderberg, Terese E. [Department of Biology and Environmental Science, Linnaeus University, SE-391 82 Kalmar (Sweden); Hogmalm, K. Johan [Department of Earth Sciences, University of Gothenburg, Gothenburg (Sweden); Filipsson, Monika E.M. [Department of Biology and Environmental Science, Linnaeus University, SE-391 82 Kalmar (Sweden)

    2015-04-15

    Risk assessments of contaminated land often involve the use of generic bioconcentration factors (BCFs), which express contaminant concentrations in edible plant parts as a function of the concentration in soil, in order to assess the risks associated with consumption of homegrown vegetables. This study aimed to quantify variability in BCFs and evaluate the implications of this variability for human exposure assessments, focusing on cadmium (Cd) and lead (Pb) in lettuce and potatoes sampled around 22 contaminated glassworks sites. In addition, risks associated with measured Cd and Pb concentrations in soil and vegetable samples were characterized and a probabilistic exposure assessment was conducted to estimate the likelihood of local residents exceeding tolerable daily intakes. The results show that concentrations in vegetables were only moderately elevated despite high concentrations in soil, and most samples complied with applicable foodstuff legislation. Still, the daily intake of Cd (but not Pb) was assessed to exceed toxicological thresholds for about a fifth of the study population. Bioconcentration factors were found to vary more than indicated by previous studies, but decreasing BCFs with increasing metal concentrations in the soil can explain why the calculated exposure is only moderately affected by the choice of BCF value when generic soil guideline values are exceeded and the risk may be unacceptable. - Highlights: • Uptake of Cd and Pb by lettuce and potatoes increased with soil contamination. • Consumption of homegrown vegetables may lead to a daily Cd intake above TDIs. • The variability in the calculated BCFs is high when compared to previous studies. • Exposure assessments are most sensitive to the choice of BCFs at low contamination.

  20. Metal uptake by homegrown vegetables – The relative importance in human health risk assessments at contaminated sites

    International Nuclear Information System (INIS)

    Augustsson, Anna L.M.; Uddh-Söderberg, Terese E.; Hogmalm, K. Johan; Filipsson, Monika E.M.

    2015-01-01

    Risk assessments of contaminated land often involve the use of generic bioconcentration factors (BCFs), which express contaminant concentrations in edible plant parts as a function of the concentration in soil, in order to assess the risks associated with consumption of homegrown vegetables. This study aimed to quantify variability in BCFs and evaluate the implications of this variability for human exposure assessments, focusing on cadmium (Cd) and lead (Pb) in lettuce and potatoes sampled around 22 contaminated glassworks sites. In addition, risks associated with measured Cd and Pb concentrations in soil and vegetable samples were characterized and a probabilistic exposure assessment was conducted to estimate the likelihood of local residents exceeding tolerable daily intakes. The results show that concentrations in vegetables were only moderately elevated despite high concentrations in soil, and most samples complied with applicable foodstuff legislation. Still, the daily intake of Cd (but not Pb) was assessed to exceed toxicological thresholds for about a fifth of the study population. Bioconcentration factors were found to vary more than indicated by previous studies, but decreasing BCFs with increasing metal concentrations in the soil can explain why the calculated exposure is only moderately affected by the choice of BCF value when generic soil guideline values are exceeded and the risk may be unacceptable. - Highlights: • Uptake of Cd and Pb by lettuce and potatoes increased with soil contamination. • Consumption of homegrown vegetables may lead to a daily Cd intake above TDIs. • The variability in the calculated BCFs is high when compared to previous studies. • Exposure assessments are most sensitive to the choice of BCFs at low contamination

  1. Corrosion product identification and relative rates of corrosion of candidate metals in an irradiated air-steam environment

    International Nuclear Information System (INIS)

    Reed, D.T.; Swayambunathan, V.; Tani, B.S.; Van Konynenburg, R.A.

    1989-01-01

    Previously reported work by others indicates that dicopper trihydroxide nitrate, Cu 2 NO 3 (OH) 3 , forms on copper and copper alloys subjected to irradiated moist air near room temperature. We have performed experiments over a range of temperature and humidity, and have found that this species is formed at temperatures up to at least 150 degree C if low to intermediate relative humidities are present. At 150 degree C and 100% relative humidity, only Cu 2 O and CuO were observed. The relative general corrosion rates of the copper materials tested in 1-month experiments at dose rates of 0.7 and 2.0 kGy/h were Cu > 70/30 Cu--Ni > Al-bronze. High-nickel alloy 825 showed no observable corrosion. 29 refs., 4 tabs

  2. Heavy metals

    OpenAIRE

    Adriano, Domy; VANGRONSVELD, Jaco; Bolan, N.S.; Wenzel, W.W.

    2005-01-01

    - Sources of Metals in the Environment - Environmental Contamination - Retention and Dynamics of Metals in Soils - Adsorption - Complexation - Precipitation - Bioavailability–Natural Attenuation Interactions - Biological Response to Metals - Soil Remediation

  3. Grey relational analysis for evaluating the effects of different rates of wine lees-derived biochar application on a plant-soil system with multi-metal contamination.

    Science.gov (United States)

    Xu, Min; Zhu, Qihong; Wu, Jun; He, Yan; Yang, Gang; Zhang, Xiaohong; Li, Li; Yu, Xiaoyu; Peng, Hong; Wang, Lilin

    2018-03-01

    In this study, grey relational analysis (GRA) was used to investigate the effects of different application rates of wine lees-derived biochar on a plant-soil system with multi-metal contamination. A pot experiment was conducted to determine rice growth in multi-metal-contaminated soil amended with samples of wine lees-derived biochar, and 47 indicators (including soil properties, microbial activity, and plant physiology) were selected as evaluation indexes to assess the plant-soil system. The results indicated that higher wine lees-derived biochar application rates (2% W/W) were favorable for soil fertility, the bioconcentration factor (BF), and the mobility factor (MF, %) (with the exception of Cr, Zn, and Hg), but an application of 1% produced the highest plant growth, enzymatic activities, and bacterial diversity. The richness of the bacterial communities was reduced in the soil amended with the wine lees-derived biochar. According to the GRA assessment, the 1% application rate of wine lees-derived biochar was more suitable for restoring the holistic plant-soil system than were the application rates of 0, 0.5, and 2% (W/W). Furthermore, this study shows that GRA is a useful method for evaluating plant-soil systems.

  4. Atmospheric deposition of heavy metals in transilvanian plateau of romania studied by the moss bio monitoring Technique employing nuclear and related analytical Techniques and gis technology

    International Nuclear Information System (INIS)

    Lucaciu, Adriana; Craciun, L.; Cuculeanu, V.; Eseanu, D.

    2001-01-01

    This paper presents data for 39 elements of 69 moss samples (Hypnum cupressiforme) collected in the Transilvanian Plateau of Romania. This results have obtained in the framework of the project Atmospheric Deposition of Heavy Metals in Rural and Urban Areas of Romania Studied by the Moss Bio monitoring Technique Employing Nuclear and Related Analytical Techniques and GIS Technology carried out under the auspices of the International Atomic Energy Agency, Vienna.The samples collected have been analyzed by ENAA with the exception of Cu, Cd, and Pb which were determined by AAS. IAEA certified materials were used to ensure the quality of the measurements. The regional concentration variations of selected elements are presented in the form of maps constructed by GIS technology. Extremely high values are observed for elements such as Cu, Zn, As and Sb in parts of this territory affected by local metal industries. The levels are among the highest observed in the world, and could be partly responsible for the unfortunate health situation in some of these areas

  5. Quantifying the impact of relativity and of dispersion interactions on the activation of molecular oxygen promoted by noble metal nanoparticles

    KAUST Repository

    Kanoun, Mohammed; Cavallo, Luigi

    2014-01-01

    an energy barrier close to 20 kcal/mol on Ag38, which decreases to slightly more than 10 kcal/mol on Au38. This behavior is analyzed to quantify the impact of relativity and of dispersion interactions through a comparison of nonrelativistic, scalar

  6. New applications in EPA’s ECOTOX Knowledge System: Assimilating relative potencies of metals across chemical and biological species from literature-based toxicity effects data.

    Science.gov (United States)

    Toxicity of metals in field settings can vary widely among ionic chemical species and across biological receptors. Thus, a challenge often found in developing TRVs for the risk assessment of metals is identifying the most appropriate metal and biological species combinations for...

  7. Loading of Two Related Metal-Organic Frameworks (MOFs, [Cu2(bdc2(dabco] and [Cu2(ndc2(dabco], with Ferrocene

    Directory of Open Access Journals (Sweden)

    Wolfgang Wenzel

    2011-09-01

    Full Text Available We have studied the loading of two related, similar porous metal-organic frameworks (MOFs [Cu2(bdc2(dabco] (1, and [Cu2(ndc2(dabco] (2 with ferrocene by exposing bulk powder samples to the corresponding vapor. On the basis of powder X-ray diffraction data and molecular dynamics (MD calculations we propose that each pore can store one ferrocene molecule. Despite the rather pronounced similarity of the two MOFs a quite different behavior is observed, for 1 loading with ferrocene leads to an anisotropic 1% contraction, whereas for 2 no deformation is observed. Mössbauer spectroscopy studies reveal that the Fe oxidation level remains unchanged during the process. Time dependent studies reveal that the diffusion constant governing the loading from the gas-phase for 1 is approximately three times larger than the value for 2.

  8. Antibiotic resistance genes in surface water of eutrophic urban lakes are related to heavy metals, antibiotics, lake morphology and anthropic impact.

    Science.gov (United States)

    Yang, Yuyi; Xu, Chen; Cao, Xinhua; Lin, Hui; Wang, Jun

    2017-08-01

    Urban lakes are impacted by heavy human activities and represent potential reservoirs for antibiotic resistance genes. In this study, six urban lakes in Wuhan, central China were selected to analyze the distribution of sulfonamide resistance (sul) genes, tetracycline resistance (tet) genes and quinolone resistance (qnr) genes and their relationship with heavy metals, antibiotics, lake morphology and anthropic impact. sul1 and sul2 were detected in all six lakes and dominated the types of antibiotic resistance genes, which accounted for 86.28-97.79% of the total antibiotic resistance gene abundance. For eight tested tet genes, antibiotic efflux pumps (tetA, tetB, tetC, and tetG) genes were all observed in six lakes and had higher relative abundance than ribosomal protection protein genes (tetM and tetQ). For 4 plasmid mediated quinolone resistance genes, only qnrD is found in all six lakes. The class I integron (intI1) is also found to be a very important media for antibiotic resistance gene propagation in urban lakes. The results of redundancy analysis and variation partitioning analysis showed that antibiotic and co-selection with heavy metals were the major factors driving the propagation of antibiotic resistance genes in six urban lakes. The heavily eutrophic Nanhu Lake and Shahu Lake which located in a high density building area with heavy human activities had the higher relative abundance of total antibiotic resistance genes. Our study could provide a useful reference for antibiotic resistance gene abundance in urban lakes with high anthropic impact.

  9. Investigation of the electronic structure of high-temperature superconductors and related transition metal oxides with near-edge x-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Gerhold, S.

    2001-01-01

    The unoccupied electronic structure and its orbital character has been studied with polarization-dependent near-edge x-ray absorption spectroscopy (NEXAFS) for selected high-temperature superconductors (HTSC) and related transition metal oxides. Although YBa 2 Cu 3 O 7-δ (Y-123) is arguably the best-investigated HTSC a conclusive NEXAFS study on how partial substitution of Cu by other transition metals affects the electronic structure has sorely been missing. The study presented here on a series of well characterized YBa 2 Cu 3-x Fe x O y single crystals shows that the cause for T c suppression is not at all magnetic pair breaking but charge carrier depletion, primarily in the chains; effects from disorder cannot be excluded. Annealing at high oxygen pressure increases along with oxygen content both the hole concentration and T c . Fe 3d-O 2p-derived states contribute prominently to the spectra for all polarizations a few eV above E F . Iron prefers a trivalent state in Y-123; upon reduction a spin transition can be observed. As YBa 2 Cu 3-x Fe x O y single crystals cannot be detwinned it is very difficult to distinguish between contributions from planes and chains to the spectra. In this situation thin films grown with a reduced degree of twinning ('twin-poor') allow more detailed investigations. An extended self-absorption correction was developed for fluorescence yield NEXAFS on epitactical HTSC thin films. Its application to twin-poor Y-123 thin films demonstrates that (apart from the effect of residual twins) the spectral information is equivalent to that of detwinned single crystals for a range of optimum film thicknesses, and this in turn allows to augment the NEXAFS study of YBa 2 Cu 3-x Fe x O y with spectra for corresponding twin-poor thin films. The system Ca 2-x (Sr,La) x RuO 4 is structurally related to the HTSCs; the development of its unoccupied electronic structure with x was investigated in this work, with emphasis on the metal

  10. Glassy metals

    CERN Document Server

    Russew, Krassimir

    2016-01-01

    The topics discussed in this book focus on fundamental problems concerning the structural relaxation of amorphous metallic alloys, above all the possibility of studying it on the basis of viscous flow behavior and its relation to rheological anomalies, such as bend stress relaxation, thermal expansion, specific heat, density changes, and crystallization. Most relaxation studies deal with the relaxation changes of a single definite material property, and not with a wider spectrum of physical properties integrated into a common framework. This book shows that it is possible to describe these property changes on the basis of a more comprehensive theoretical understanding of their mechanism.

  11. Alkali metal hydride formation

    International Nuclear Information System (INIS)

    1976-01-01

    The present invention relates to a method of producing alkali metal hydrides by absorbing hydrogen gas under pressure into a mixture of lower alkyl mono amines and alkali metal alkyl amides selected from sodium and potassium amides formed from said amines. The present invention also includes purification of a mixture of the amines and amides which contain impurities, such as is used as a catalytic exchange liquid in the enrichment of deuterium, involving the formation of the alkali metal hydride

  12. Quantifying the impact of relativity and of dispersion interactions on the activation of molecular oxygen promoted by noble metal nanoparticles

    KAUST Repository

    Kanoun, Mohammed

    2014-06-26

    We compared the mechanism of O2 dissociation catalyzed by Cu38, Ag38, and Au38 nanoparticles. Overall, our results indicate that O2 dissociation is extremely easy on Cu38, with an almost negligible barrier for the O-O breaking step. It presents an energy barrier close to 20 kcal/mol on Ag38, which decreases to slightly more than 10 kcal/mol on Au38. This behavior is analyzed to quantify the impact of relativity and of dispersion interactions through a comparison of nonrelativistic, scalar-relativistic, and dispersioncorrected DFT methods. Nonrelativistic calculations show a clear trend down the triad, with larger in size nanoparticle (NP), weaker O2 adsorption energy, and higher O2 dissociation barrier, which is so high for Au38 to be in sharp contrast with the mild conditions used experimentally. Inclusion of relativity has no impact on the O2 adsorption energy, but it reduces the energy barrier for O2 dissociation on Au38 from 30.1 to 11.4 kcal/mol, making it even lower than that on Ag38 and consistent with the mild conditions used experimentally. Dispersion interactions have a remarkable role in improving the adsorption ability of O2 on the heavier Ag38 and especially Au38 NPs, contributing roughly 50% of the total adsorption energy, while they have much less impact on O2 adsorption on Cu38.

  13. Body burden of aluminum in relation to central nervous system function among metal inert-gas welders.

    Science.gov (United States)

    Riihimäki, V; Hänninen, H; Akila, R; Kovala, T; Kuosma, E; Paakkulainen, H; Valkonen, S; Engström, B

    2000-04-01

    The relationship between elevated internal aluminum loads and central nervous system function was studied among aluminum welders, and the threshold level for adverse effect was defined. For 65 aluminum welders and 25 current mild steel welders body burden was estimated, and the aluminum concentrations in serum (S-Al) and urine (U-Al) were analyzed with graphite furnace atomic absorption spectrometry with Zeeman background correction. Referents and low-exposure and high-exposure groups were defined according to an aggregated measure of aluminum body burden, the group median S-Al levels being 0.08, 0.14, and 0.46 micromol/l, respectively, and the corresponding values for U-Al being 0.4, 1.8, and 7.1 micromol/l. Central nervous system functions were assessed with a neuropsychological test battery, symptom and mood questionnaires, a visual and quantitative analysis of electroencephalography (EEG), and P3 event-related potentials with pitch and duration paradigms. Subjective symptoms showed exposure-related increases in fatigue, mild depression, and memory and concentration problems. Neuropsychological testing revealed a circumscribed effect of aluminum, mainly in tasks demanding complex attention and the processing of information in the working memory system and in the analysis and recall of abstract visual patterns. The visual EEG analysis revealed pathological findings only for aluminum welders. Mild, diffuse abnormalities were found in 17% of the low-exposure group and 27% of the high-exposure group, and mild to moderate epileptiform abnormalities at a frequency of 7% and 17%, respectively. Both objective neurophysiological and neuropsychological measures and subjective symptomatology indicated mild but unequivocal findings dose-dependently associated with increased aluminum body burden. The study indicates that the body burden threshold for adverse effect approximates an U-Al value of 4-6 micromol/l and an S-Al value of 0.25-0.35 micromol/l among aluminum welders.

  14. Systematically extracting metal- and solvent-related occupational information from free-text responses to lifetime occupational history questionnaires.

    Science.gov (United States)

    Friesen, Melissa C; Locke, Sarah J; Tornow, Carina; Chen, Yu-Cheng; Koh, Dong-Hee; Stewart, Patricia A; Purdue, Mark; Colt, Joanne S

    2014-06-01

    Lifetime occupational history (OH) questionnaires often use open-ended questions to capture detailed information about study participants' jobs. Exposure assessors use this information, along with responses to job- and industry-specific questionnaires, to assign exposure estimates on a job-by-job basis. An alternative approach is to use information from the OH responses and the job- and industry-specific questionnaires to develop programmable decision rules for assigning exposures. As a first step in this process, we developed a systematic approach to extract the free-text OH responses and convert them into standardized variables that represented exposure scenarios. Our study population comprised 2408 subjects, reporting 11991 jobs, from a case-control study of renal cell carcinoma. Each subject completed a lifetime OH questionnaire that included verbatim responses, for each job, to open-ended questions including job title, main tasks and activities (task), tools and equipment used (tools), and chemicals and materials handled (chemicals). Based on a review of the literature, we identified exposure scenarios (occupations, industries, tasks/tools/chemicals) expected to involve possible exposure to chlorinated solvents, trichloroethylene (TCE) in particular, lead, and cadmium. We then used a SAS macro to review the information reported by study participants to identify jobs associated with each exposure scenario; this was done using previously coded standardized occupation and industry classification codes, and a priori lists of associated key words and phrases related to possibly exposed tasks, tools, and chemicals. Exposure variables representing the occupation, industry, and task/tool/chemicals exposure scenarios were added to the work history records of the study respondents. Our identification of possibly TCE-exposed scenarios in the OH responses was compared to an expert's independently assigned probability ratings to evaluate whether we missed identifying

  15. Explosion metal welding

    International Nuclear Information System (INIS)

    Popoff, A.A.

    1976-01-01

    Process parameters pertaining to welding similar and dissimilar metals using explosives are reviewed. The discussion centers on the interrelationship of physical parameters which play a part in achieving desirable metallurgical results. Present activities in explosion metal welding at LASL are presented and shown how they related to the interests of the ERDA community

  16. Interplay of metals and bromine with dioxin-related compounds concentrated in e-waste open burning soil from Agbogbloshie in Accra, Ghana.

    Science.gov (United States)

    Fujimori, Takashi; Itai, Takaaki; Goto, Akitoshi; Asante, Kwadwo A; Otsuka, Masanari; Takahashi, Shin; Tanabe, Shinsuke

    2016-02-01

    Open burning of electronic waste (e-waste) releases various metals and organohalogen compounds in the environment. Here we investigated the interplay of metals (Cu, Pb, Zn, Fe, Co, and Sr) and bromine (Br) in the formation of dioxin-related compounds (DRCs), including polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs), as well as non-regulated DRCs such as polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) and their monobrominated PCDD/Fs in soils sampled from open burning e-waste sites at Agbogbloshie in Accra, Ghana. The predominant DRCs were PBDFs, PCDFs, PCDDs, and DL-PCBs. Statistical analyzes, X-ray absorption spectroscopy, and the PCDF/PCDD ratio suggested possible formation paths of PCDD/Fs and DL-PCBs by catalytic behaviors of copper chlorides (CuCl, CuCl2, and Cu2(OH)3Cl) and thermal breakdown of polyvinyl chloride. Predominant formation of brominated furans may be derived from electron transfer from intermediates of PBDE to copper, Cu(II) → Cu(I). Lead chloride also contributed to generate DRCs and may become highly bioaccessible through the open burning of e-waste. The main zinc species (ZnCl2 and ZnS) suggested a possible relationship to generate DRCs and specific zinc source such as tire burning. Cu, Pb, Zn, and Br contained in various e-wastes, wires/cables, plastics, and tires strongly influenced generation of many DRCs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Nanocarrier-mediated foliar zinc fertilization influences expression of metal homeostasis related genes in flag leaves and enhances gluten content in durum wheat.

    Science.gov (United States)

    Deshpande, Paresh; Dapkekar, Ashwin; Oak, Manoj; Paknikar, Kishore; Rajwade, Jyutika

    2018-01-01

    Wheat is the staple food for most of the world's population; however, it is a poor source of zinc. Foliar fertilization of zinc via zinc loaded chitosan nanocarriers (Zn-CNP) post-anthesis has proved to be a promising approach for grain zinc enhancement in durum wheat as evidenced in our earlier study. However, the molecular mechanism of uptake of zinc via Zn-CNP remains unclear. Foliar application of Zn-CNP was performed at post anthesis stages in two durum wheat cultivars (MACS 3125 and UC1114, containing the Gpc-B1 gene), and expression levels of several metal-related genes were analyzed during early senescence. Zn-CNP application indeed caused changes in gene expression as revealed by qPCR data on representative genes involved in metal homeostasis, phloem transporters, and leaf senescence. Furthermore, zinc-regulated transporters and iron (Fe)-regulated transporter-like protein (ZIP) family [ZIP1, ZIP7, ZIP15], CA (carbonic anhydrase), and DMAS (2'-deoxymugineic acid synthase) in flag leaves exhibited significant correlation with zinc content in the seeds. The analysis of grain endosperm proteins showed enhancement of gamma gliadins while other gluten subunits decreased. Gene expression within ZIP family members varied with the type of cultivar mostly attributed to the Gpc-B1, concentration of external zinc ions as well as the type of tissue analyzed. Correlation analysis revealed the involvement of the selected genes in zinc enhancement. At the molecular level, uptake of zinc via Zn-CNP nanocarrier was comparable to the uptake of zinc via common zinc fertilizers i.e. ZnSO4.

  18. Tracing sediment sources in the Williams River catchment using caesium-137 and heavy metals: towards an assessment of the relative importance of surface erosion and gully erosion

    International Nuclear Information System (INIS)

    Krause, A.K.; Kalma, J.D.; Loughran, R.J.

    1999-01-01

    Recent sediment sourcing in the 1175km 2 Williams River catchment near Newcastle, NSW, has involved the use of caesium-137 ( 137 Cs) and heavy metals to identify zones of erosion and estimate erosion rates. Sediment sources to the Williams River include sheet erosion from forested and grazed lands, stream channels (especially banks), gullies and roads. The fallout environmental radioisotope 137 Cs was used to assess the erosion status of five vegetated slopes using soil sampling along transects. The net loss or gain of 137 Cs at each sampling point was compared with the 137 Cs level at a reference site at the slope crest. Net soil loss at each point was calculated from an Australian regression model relating net soil loss from runoff-erosion plots to 137 Cs deficit in soils (n=34; r=0.84). Net soil gain was calculated using the regression model in reverse mode. A weighted net soil loss (or gain) was then calculated for each slope transect. Results showed low net soil loss, ranging from zero to 0.64 t ha -1 yr 1 , suggesting that slopes were not major contributors of sediment to the Williams River. A small sub-catchment south of Wirragulla Hill, typical of the lower Williams region, was selected for more detailed tracing of sediment sources. The catchment contains gullies, sheet-erosion exposed sub-soil, grassland and one unsealed road. Heavy metals and 137 Cs have been used to fingerprint the sources, and these measurements will be compared with suspended sediment collected from drainage water in the creek. Only preliminary results have been obtained for this component of the study. The paper will assess these two approaches for the identification of sediment sources and discuss practical applications in water resources management

  19. Nanocarrier-mediated foliar zinc fertilization influences expression of metal homeostasis related genes in flag leaves and enhances gluten content in durum wheat.

    Directory of Open Access Journals (Sweden)

    Paresh Deshpande

    Full Text Available Wheat is the staple food for most of the world's population; however, it is a poor source of zinc. Foliar fertilization of zinc via zinc loaded chitosan nanocarriers (Zn-CNP post-anthesis has proved to be a promising approach for grain zinc enhancement in durum wheat as evidenced in our earlier study. However, the molecular mechanism of uptake of zinc via Zn-CNP remains unclear.Foliar application of Zn-CNP was performed at post anthesis stages in two durum wheat cultivars (MACS 3125 and UC1114, containing the Gpc-B1 gene, and expression levels of several metal-related genes were analyzed during early senescence. Zn-CNP application indeed caused changes in gene expression as revealed by qPCR data on representative genes involved in metal homeostasis, phloem transporters, and leaf senescence. Furthermore, zinc-regulated transporters and iron (Fe-regulated transporter-like protein (ZIP family [ZIP1, ZIP7, ZIP15], CA (carbonic anhydrase, and DMAS (2'-deoxymugineic acid synthase in flag leaves exhibited significant correlation with zinc content in the seeds. The analysis of grain endosperm proteins showed enhancement of gamma gliadins while other gluten subunits decreased. Gene expression within ZIP family members varied with the type of cultivar mostly attributed to the Gpc-B1, concentration of external zinc ions as well as the type of tissue analyzed. Correlation analysis revealed the involvement of the selected genes in zinc enhancement.At the molecular level, uptake of zinc via Zn-CNP nanocarrier was comparable to the uptake of zinc via common zinc fertilizers i.e. ZnSO4.

  20. Relativity

    CERN Document Server

    Einstein, Albert

    2013-01-01

    Time magazine's ""Man of the Century"", Albert Einstein is the founder of modern physics and his theory of relativity is the most important scientific idea of the modern era. In this short book, Einstein explains, using the minimum of mathematical terms, the basic ideas and principles of the theory that has shaped the world we live in today. Unsurpassed by any subsequent books on relativity, this remains the most popular and useful exposition of Einstein's immense contribution to human knowledge.With a new foreword by Derek Raine.

  1. Assessment of human health risk related to metals by the use of biomonitors in the province of Córdoba, Argentina.

    Science.gov (United States)

    Carreras, Hebe A; Wannaz, Eduardo D; Pignata, María L

    2009-01-01

    The evaluation of metal contents in the environment is of vital importance for the assessment of human exposure. Thus the species Usnea amblyoclada, Ramalina celastri and Tillandsia capillaris were tested as bioaccumulators of transition metals in the urban area of Córdoba city, Argentina. The level of metals on biomonitors was compared to that of total deposition samples. All three species discriminated zones within the urban area of Córdoba city with different pollution levels; they revealed high levels of Zn in the downtown area and confirmed high levels of some transition metals in an industrial area. The correlation analysis revealed that the lichen R. celastri had the highest correlation rates with total deposition samples, suggesting it is a valuable biomonitor of atmospheric pollution. A significant relationship was also observed between respiratory diseases in children and the contents of metal accumulated in R. celastri and T. capillaris, indicating their usefulness when assessing human exposure to metals.

  2. Influence of a step-change in metal exposure (Cd, Cu, Zn) on metal accumulation and subcellular partitioning in a freshwater bivalve, Pyganodon grandis: A long-term transplantation experiment between lakes with contrasting ambient metal levels

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Sophie [INRS-Eau, Terre et Environnement, Université du Québec, 490 de la Couronne, Québec, QC G1K 9A9 (Canada); Bonneris, Emmanuelle [INRS-Eau, Terre et Environnement, Université du Québec, 490 de la Couronne, Québec, QC G1K 9A9 (Canada) and Bayer S.A.S., Bayer CropScience, 16 Rue Jean-Marie Leclair, CP 90106, F 69266 Lyon Cedex 09 (France); Michaud, Annick [INRS-Eau, Terre et Environnement, Université du Québec, 490 de la Couronne, Québec, QC G1K 9A9 (Canada) and Direction des Évaluations environnementales, Ministère du Développement durable, de l’Environnement et des Parcs, 675, boul. René-Lévesque Est, 6e étage, Québec, QC G1R 5V7 (Canada); Pinel-Alloul, Bernadette [Groupe de Recherche Interuniversitaire en Limnologie et Environnement Aquatique (GRIL), Département de Sciences Biologiques, Université de Montréal, C.P. 6128, Montréal, QC H3C 3J7 (Canada); Campbell, Peter G.C., E-mail: peter.campbell@ete.inrs.ca [INRS-Eau, Terre et Environnement, Université du Québec, 490 de la Couronne, Québec, QC G1K 9A9 (Canada)

    2013-05-15

    Highlights: ? We transferred freshwater bivalves from a reference lake to a Cd and Zn contaminated lake. ? Changes in metal accumulation and subcellular partitioning were followed over time (up to 860 d). ? Metal detoxification strategies differed between target organs (gills vs. digestive gland). ? The ability to handle Cd is inherent in P. grandis, not a trait acquired after long-term adaptation. -- Abstract: The objective of the present field experiment was to identify detoxification responses in the gills and digestive gland of a freshwater unionid bivalve, Pyganodon grandis, subjected to a step-change in metal exposure. Adult bivalves were transferred from a reference site (Lake Opasatica) and a metal-contaminated lake (Lake Héva) to a second contaminated lake (Lake Vaudray) in northwestern Quebec, Canada. Changes in organ metal concentrations, in the subcellular distribution of metals and in metallothionein concentrations were followed over time (t = 0, 132, (400) and 860 days). At each collection time and for each bivalve, the gills and digestive gland were excised and gently homogenized; six sub-cellular fractions were separated by differential centrifugation and analyzed for their Cd, Cu and Zn content, and metallothionein was quantified independently. Metal detoxification strategies were shown to differ between target organs: in the gills, incoming metals were sequestered largely in the granules, whereas in the digestive gland the same metals primarily accumulated in the cytosol, in the metallothionein-like protein fraction. These metal-handling strategies, as employed by the metal-naïve bivalves originating in the reference lake, closely resemble those identified in free-living P. grandis chronically exposed in the metal-contaminated lake, suggesting that the ability to handle incoming metals (Cd in particular) is inherent in P. grandis and is not a trait acquired after long-term adaptation of the bivalve to metal-contaminated environments. The

  3. Soil heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Sherameti, Irena [Jena Univ. (Germany). Inst. fuer Allgemeine Botanik und Pflanzenphysiologie; Varma, Ajit (eds.) [Amity Univ., Uttar Pradesh (India). Amity Inst. of Microbial Technology; Amity Science, Technology and Innovation Foundation, Noida, UP (India)

    2010-07-01

    Human activities have dramatically changed the composition and organisation of soils. Industrial and urban wastes, agricultural application and also mining activities resulted in an increased concentration of heavy metals in soils. How plants and soil microorganisms cope with this situation and the sophisticated techniques developed for survival in contaminated soils is discussed in this volume. The topics presented include: the general role of heavy metals in biological soil systems; the relation of inorganic and organic pollutions; heavy metal, salt tolerance and combined effects with salinity; effects on abuscular mycorrhizal and on saprophytic soil fungi; heavy metal resistance by streptomycetes; trace element determination of environmental samples; the use of microbiological communities as indicators; phytostabilization of lead polluted sites by native plants; effects of soil earthworms on removal of heavy metals and the remediation of heavy metal contaminated tropical land. (orig.)

  4. Combined and Relative Effect Levels of Perceived Risk, Knowledge, Optimism, Pessimism, and Social Trust on Anxiety among Inhabitants Concerning Living on Heavy Metal Contaminated Soil.

    Science.gov (United States)

    Tang, Zhongjun; Guo, Zengli; Zhou, Li; Xue, Shengguo; Zhu, Qinfeng; Zhu, Huike

    2016-11-02

    This research aims at combined and relative effect levels on anxiety of: (1) perceived risk, knowledge, optimism, pessimism, and social trust; and (2) four sub-variables of social trust among inhabitants concerning living on heavy metal contaminated soil. On the basis of survey data from 499 Chinese respondents, results suggest that perceived risk, pessimism, optimism, and social trust have individual, significant, and direct effects on anxiety, while knowledge does not. Knowledge has significant, combined, and interactive effects on anxiety together with social trust and pessimism, respectively, but does not with perceived risk and optimism. Social trust, perceived risk, pessimism, knowledge, and optimism have significantly combined effects on anxiety; the five variables as a whole have stronger predictive values than each one individually. Anxiety is influenced firstly by social trust and secondly by perceived risk, pessimism, knowledge, and optimism. Each of four sub-variables of social trust has an individual, significant, and negative effect on anxiety. When introducing four sub-variables into one model, trust in social organizations and in the government have significantly combined effects on anxiety, while trust in experts and in friends and relatives do not; anxiety is influenced firstly by trust in social organization, and secondly by trust in the government.

  5. New metals

    International Nuclear Information System (INIS)

    Bergqvist, U.

    1983-12-01

    The aim of this report is to estimate the exposure to various metals and metal compounds and discuss the available information of the possible toxic effects of these metals and compounds. In the first section, some metals are defined as those with either a large or a fast increasing exposure to living organisms. The available information on toxicity is discussed in the second section. In the third section interesting metals are defined as compounds having a large exposure and an apparent insufficient knowledge of their possible toxic effects. Comments on each of these metals are also to be found in the third section. (G.B.)

  6. Production of magnesium metal

    Science.gov (United States)

    Blencoe, James G [Harriman, TN; Anovitz, Lawrence M [Knoxville, TN; Palmer, Donald A [Oliver Springs, TN; Beard, James S [Martinsville, VA

    2010-02-23

    A process of producing magnesium metal includes providing magnesium carbonate, and reacting the magnesium carbonate to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The carbon dioxide is used as a reactant in a second process. In another embodiment of the process, a magnesium silicate is reacted with a caustic material to produce magnesium hydroxide. The magnesium hydroxide is reacted with a source of carbon dioxide to produce magnesium carbonate. The magnesium carbonate is reacted to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The invention further relates to a process for production of magnesium metal or a magnesium compound where an external source of carbon dioxide is not used in any of the reactions of the process. The invention also relates to the magnesium metal produced by the processes described herein.

  7. Influence of N deficiency and salinity on metal (Pb, Zn and Cu) accumulation and tolerance by Rhizophora stylosa in relation to root anatomy and permeability

    International Nuclear Information System (INIS)

    Cheng Hao; Wang Youshao; Ye Zhihong; Chen Danting; Wang Yutu; Peng Yalan; Wang Liying

    2012-01-01

    Effects of N deficiency and salinity on root anatomy, permeability and metal (Pb, Zn and Cu) translocation and tolerance were investigated using mangrove seedlings of Rhizophora stylosa. The results showed that salt could directly reduce radial oxygen loss (ROL) by stimulation of lignification within exodermis. N deficiency, oppositely, would reduce lignification. Such an alteration in root permeability may also influence metal tolerance by plants. The data indicated that a moderate salinity could stimulate a lignified exodermis that delayed the entry of metals into the roots and thereby contributed to a higher metal tolerance, while N deficiency would aggravate metal toxicity. The results from sand pot trail further confirmed this issue. This study provides a barrier property of the exodermis in dealing with environments. The plasticity of root anatomy is likely an adaptive strategy to regulate the fluxes of gases, nutrients and toxins at root–soil interface. - Highlights: ► Salt induced lignified exodermis which slowed down metal entry into the plants. ► N deficiency, oppositely, aggravated metal mobility and toxicity. ► Barrier properties of the exodermis. - N deficiency and salinity regulate the apoplastic transport barrier of metals and their toxicities

  8. Relevance of hair and spines of the European hedgehog (Erinaceus europaeus) as biomonitoring tissues for arsenic and metals in relation to blood

    NARCIS (Netherlands)

    Vermeulen, F.; Havé, D' H.; Mubiana, V.K.; Brink, van den N.W.; Blust, R.; Bervoets, L.; Coen, De W.

    2009-01-01

    Hair has been proven to be suitable for non-destructive and non-invasive exposure assessments in human and mammal populations. A previous study with European hedgehog (Erinaceus europaeus) showed that, for some metals, hair and spine metal concentrations were positively correlated to levels in

  9. Changes in cell-type composition in digestive gland of slugs and its influence in biomarkers following transplantation between a relatively unpolluted and a chronically metal-polluted site

    International Nuclear Information System (INIS)

    Zaldibar, B.; Cancio, I.; Soto, M.; Marigomez, I.

    2008-01-01

    Changes in cell-type composition (CCTC) is a general phenomenon that takes place in the digestive gland epithelium of stressed molluscs. The aim of the present work was to determine whether CCTC is a reversible process in the digestive gland of sentinel slugs chronically exposed to metal pollution and how CCTC affects metal accumulation parameters and different cell and tissue biomarkers of exposure and effect. Slugs (Arion ater) from an abandoned zinc mine were transferred to a relatively unpolluted site and the other way around for 3, 10 and 28 d. The volume density of black silver deposits (Vv BSD ) after autometallography, and metallothionein (MT) levels were used as biomarkers of exposure to metals and CCTC and lysosomal responses were selected as effect biomarkers. Results indicated that slugs were sensitive to recent metal pollution; however, slugs chronically exposed to metals presented some characteristic features and were less responsive to pollution cessation without signs of CCTC reversal. - Cell and tissue-level biomarkers in slugs after recent and chronic metal pollution

  10. Electrical Conductivity in Transition Metals

    Science.gov (United States)

    Talbot, Christopher; Vickneson, Kishanda

    2013-01-01

    The aim of this "Science Note" is to describe how to test the electron-sea model to determine whether it accurately predicts relative electrical conductivity for first-row transition metals. In the electron-sea model, a metal crystal is viewed as a three-dimensional array of metal cations immersed in a sea of delocalised valence…

  11. Silicone metalization

    Energy Technology Data Exchange (ETDEWEB)

    Maghribi, Mariam N. (Livermore, CA); Krulevitch, Peter (Pleasanton, CA); Hamilton, Julie (Tracy, CA)

    2008-12-09

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  12. Global DNA methylation in earthworms: a candidate biomarker of epigenetic risks related to the presence of metals/metalloids in terrestrial environments.

    Science.gov (United States)

    Santoyo, María Maldonado; Flores, Crescencio Rodríguez; Torres, Adolfo Lopez; Wrobel, Kazimierz; Wrobel, Katarzyna

    2011-10-01

    In this work, possible relationships between global DNA methylation and metal/metalloid concentrations in earthworms have been explored. Direct correlation was observed between soil and tissue As, Se, Sb, Zn, Cu, Mn, Ag, Co, Hg, Pb (p< 0.05). Speciation results obtained for As and Hg hint at the capability of earthworms for conversion of inorganic element forms present in soil to methylated species. Inverse correlation was observed between the percentage of methylated DNA cytosines and total tissue As, As + Hg, As + Hg + Se + Sb (β = -0.8456, p = 0.071; β = -0.9406, p = 0.017; β = -0.9526, p = 0.012 respectively), as well as inorganic As + Hg (β = -0.8807, p = 0.049). It was concluded that earthworms would be particularly helpful as bioindicators of elements undergoing in vivo methylation and might also be used to assess the related risk of epigenetic changes in DNA methylation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Metals production

    Science.gov (United States)

    Beck, Theodore S.

    1992-01-01

    Existing procedures for design of electrochemical plants can be used for design of lunar processes taking into consideration the differences in environmental conditions. These differences include: 1/6 Earth gravity, high vacuum, solar electrical and heat source, space radiation heat sink, long days and nights, and different availability and economics of materials, energy, and labor. Techniques have already been developed for operation of relatively small scale hydrogen-oxygen fuel cell systems used in the U.S. lunar landing program. Design and operation of lunar aqueous electrolytic process plants appears to be within the state-of-the-art. Finding or developing compatible materials for construction and designing of fused-magma metal winning cells will present a real engineering challenge.

  14. Global Proteome Response to Deletion of Genes Related to Mercury Methylation and Dissimilatory Metal Reduction Reveals Changes in Respiratory Metabolism in Geobacter sulfurreducens PCA.

    Science.gov (United States)

    Qian, Chen; Johs, Alexander; Chen, Hongmei; Mann, Benjamin F; Lu, Xia; Abraham, Paul E; Hettich, Robert L; Gu, Baohua

    2016-10-07

    Geobacter sulfurreducens PCA can reduce, sorb, and methylate mercury (Hg); however, the underlying biochemical mechanisms of these processes and interdependent metabolic pathways remain unknown. In this study, shotgun proteomics was used to compare global proteome profiles between wild-type G. sulfurreducens PCA and two mutant strains: a ΔhgcAB mutant, which is deficient in two genes known to be essential for Hg methylation and a ΔomcBESTZ mutant, which is deficient in five outer membrane c-type cytochromes and thus impaired in its ability for dissimilatory metal ion reduction. We were able to delineate the global response of G. sulfurreducens PCA in both mutants and identify cellular networks and metabolic pathways that were affected by the loss of these genes. Deletion of hgcAB increased the relative abundances of proteins implicated in extracellular electron transfer, including most of the c-type cytochromes, PilA-C, and OmpB, and is consistent with a previously observed increase in Hg reduction in the ΔhgcAB mutant. Deletion of omcBESTZ was found to significantly increase relative abundances of various methyltransferases, suggesting that a loss of dissimilatory reduction capacity results in elevated activity among one-carbon (C1) metabolic pathways and thus increased methylation. We show that G. sulfurreducens PCA encodes only the folate branch of the acetyl-CoA pathway, and proteins associated with the folate branch were found at lower abundance in the ΔhgcAB mutant strain than the wild type. This observation supports the hypothesis that the function of HgcA and HgcB is linked to C1 metabolism through the folate branch of the acetyl-CoA pathway by providing methyl groups required for Hg methylation.

  15. Synthesis of Binary Transition Metal Nitrides, Carbides and Borides from the Elements in the Laser-Heated Diamond Anvil Cell and Their Structure-Property Relations

    Directory of Open Access Journals (Sweden)

    Lkhamsuren Bayarjargal

    2011-09-01

    Full Text Available Transition metal nitrides, carbides and borides have a high potential for industrial applications as they not only have a high melting point but are generally harder and less compressible than the pure metals. Here we summarize recent advances in the synthesis of binary transition metal nitrides, carbides and borides focusing on the reaction of the elements at extreme conditions generated within the laser-heated diamond anvil cell. The current knowledge of their structures and high-pressure properties like high-(p; T stability, compressibility and hardness is described as obtained from experiments.

  16. Synthesis of Binary Transition Metal Nitrides, Carbides and Borides from the Elements in the Laser-Heated Diamond Anvil Cell and Their Structure-Property Relations

    Science.gov (United States)

    Friedrich, Alexandra; Winkler, Björn; Juarez-Arellano, Erick A.; Bayarjargal, Lkhamsuren

    2011-01-01

    Transition metal nitrides, carbides and borides have a high potential for industrial applications as they not only have a high melting point but are generally harder and less compressible than the pure metals. Here we summarize recent advances in the synthesis of binary transition metal nitrides, carbides and borides focusing on the reaction of the elements at extreme conditions generated within the laser-heated diamond anvil cell. The current knowledge of their structures and high-pressure properties like high-(p,T) stability, compressibility and hardness is described as obtained from experiments. PMID:28824101

  17. Variability of PAHs and trace metals in the sediments in relation to environmental characteristics of the bottom layer in the middle Adriatic Sea

    Science.gov (United States)

    Grilli, Federica; Frapiccini, Emanuela; Campanelli, Alessandra; Guicciardi, Stefano; Marini, Mauro; Marasovic, Ivona; Grbec, Branka; Skejić, Sanda; Ujević, Ivana; Lušić, Jelena

    2015-04-01

    In the framework of the project PERSEUS (Policy-oriented marine Environmental Research in the Southern EUropean Seas), two interdisciplinary surveys were carried out in April 2013 and April 2014 in the middle Adriatic Sea along the Pescara-Sibenik transect (Jabuka Pits area) and Vieste-Split transect (Palagruza Sill area) with Croatian research vessel "Bios II" and the Italian research vessel "G. Dallaporta", respectively. The main objective of these research cruises was the implementation of the Marine Strategy Framework Directive (MSFD) in the Adriatic region for collecting physical, chemical and biological data in order to get a better understanding of whole Adriatic ecosystem. The two transects are already recognised as a key areas for the interception and the study of dense water modification (Zore-Armanda, 1963; Marini et al., 2006; Grilli et al., 2013). Due to seasonal circulation patterns, they are characterized by high temporal variability of the thermohaline structure (Grbec and Morović, 1997; Vilibić, et al., 2004) and other oceanographic parameters. Long term oceanographic records from the Middle Adriatic enable better understanding of the ecosystem response to changes of atmospheric and sea conditions through physical, chemical and biological processes (Marasović et al., 1995). Several oceanographic parameters relevant and useful for the ecosystem assessment of the two areas (temperature, salinity, density, fluorescence, oxygen, nutrients, chlorophyll, phyto- and zoo-plankton as well as selected pollutants , trace metals and Polycyclic Aromatic Hydrocarbons-PAHs in sediments) were collected. In the present work, the variations of PAHs and trace metals concentration in the marine sediments are presented in relation to the physical and chemical characteristics of the bottom layer. A constant influx of metal induces more intense accumulation of anthropogenic metals, especially Cd, in sediment from Jabuka Pit, and the metal content slightly increases

  18. Metals and Neurodegeneration

    Science.gov (United States)

    Chen, Pan; Miah, Mahfuzur Rahman; Aschner, Michael

    2016-01-01

    Metals play important roles in the human body, maintaining cell structure and regulating gene expression, neurotransmission, and antioxidant response, to name a few. However, excessive metal accumulation in the nervous system may be toxic, inducing oxidative stress, disrupting mitochondrial function, and impairing the activity of numerous enzymes. Damage caused by metal accumulation may result in permanent injuries, including severe neurological disorders. Epidemiological and clinical studies have shown a strong correlation between aberrant metal exposure and a number of neurological diseases, including Alzheimer’s disease, amyotrophic lateral sclerosis, autism spectrum disorders, Guillain–Barré disease, Gulf War syndrome, Huntington’s disease, multiple sclerosis, Parkinson’s disease, and Wilson’s disease. Here, we briefly survey the literature relating to the role of metals in neurodegeneration. PMID:27006759

  19. Understanding how cells allocate metals using metal sensors and metallochaperones.

    Science.gov (United States)

    Tottey, Stephen; Harvie, Duncan R; Robinson, Nigel J

    2005-10-01

    Each metalloprotein must somehow acquire the correct metal. We review the insights into metal specificity in cells provided by studies of ArsR-SmtB DNA binding, metal-responsive transcriptional repressors, and a bacterial copper chaperone. Cyanobacteria are the one bacterial group that have known enzymatic demand for cytoplasmic copper import. The copper chaperone and ATPases that supply cyanobacterial plastocyanin and cytochrome oxidase are reviewed, along with related ATPases for cobalt and zinc. These studies highlight the contributions of protein-protein interactions to metal speciation. Metal sensors and metallochaperones, along with metal transporters and metal-storage proteins, act in concert not only to supply the correct metals but also to withhold the wrong ones.

  20. Electric-dipole absorption resonating with longitudinal optical phonon-plasmon system and its effect on dispersion relations of interface phonon polariton modes in metal/semiconductor-stripe structures

    Science.gov (United States)

    Sakamoto, Hironori; Takeuchi, Eito; Yoshida, Kouki; Morita, Ken; Ma, Bei; Ishitani, Yoshihiro

    2018-01-01

    Interface phonon polaritons (IPhPs) in nano-structures excluding metal components are thoroughly investigated because they have lower loss in optical emission or absorption and higher quality factors than surface plasmon polaritons. In previous reports, it is found that strong infrared (IR) absorption is based on the interaction of p-polarized light and materials, and the resonance photon energy highly depends on the structure size and angle of incidence. We report the optical absorption by metal/semiconductor (bulk-GaAs and thin film-AlN)-stripe structures in THz to mid-IR region for the electric field of light perpendicular to the stripes, where both of s- and p-polarized light are absorbed. The absorption resonates with longitudinal optical (LO) phonon or LO phonon-plasmon coupling (LOPC) modes, and thus is independent of the angle of incidence or structure size. This absorption is attributed to the electric dipoles by the optically induced polarization charges at the metal/semiconductor, heterointerfaces, or interfaces of high electron density layers and depression ones. The electric permittivity is modified by the formation of these dipoles. It is found to be indispensable to utilize our form of altered permittivity to explain the experimental dispersion relations of metal/semiconductor-IPhP and SPhP in these samples. This analysis reveals that the IPhPs in the stripe structures of metal/AlN-film on a SiC substrate are highly confined in the AlN film, while the permittivity of the structures of metal/bulk-GaAs is partially affected by the electric-dipoles. The quality factors of the electric-dipole absorption are found to be 42-54 for undoped samples, and the value of 62 is obtained for Al/AlN-IPhP. It is thought that metal-contained structures are not obstacles to mode energy selectivity in phonon energy region of semiconductors.

  1. Covalent bonding and band-gap formation in ternary transition-metal di-aluminides: Al4MnCo and related compounds

    International Nuclear Information System (INIS)

    Krajci, M.; Hafner, J.

    2002-01-01

    In this paper we extend our previous study of the electronic structure of and bonding mechanism in transition-metal (TM) di-aluminides to ternary systems. We have studied the character of the bonding in Al 4 MnCo and related TM di-aluminides in the C11 b (MoSi 2 ) and C54 (TiSi 2 ) crystal structures. A peculiar feature of the electronic structure of these TM di-aluminides is the existence of a semiconducting gap at the Fermi level. In our previous work we predicted a gap in Al 2 TM compounds where the TM atoms have eight valence electrons. Here we demonstrate that the semiconducting gap does not disappear if the TM sites are occupied by two different TMs, provided that the electron-per-atom ratio is conserved. Such a replacement substantially increases the class of possibly semiconducting TM di-aluminides. Substitution for 3d TMs of 4d or 5d TMs enhances the width of the gap. From the analysis of the charge density distribution and the crystal orbital overlap population, we conclude that the bonding between atoms has dominantly covalent character. This is confirmed not only by the enhanced charge density halfway between atoms, but also by the clear bonding-antibonding splitting of the electronic states. If the gaps between split states that correspond to all bonding configurations in the crystal have a common overlap at the Fermi level, the intermetallic compound becomes a semiconductor. However, the results of the total-energy calculations suggest that the existence of a band gap does not necessarily imply a stable structure. Strong covalent bonds can exist also in Al-TM structures where no band gap is observed. (author)

  2. Vapor trap for liquid metal

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, T

    1968-05-22

    In a pipe system which transfers liquid metal, inert gas (cover gas) is packed above the surface of the liquid metal to prevent oxidization of the liquid. If the metal vapor is contained in such cover gas, the circulating system of the cover gas is blocked due to condensation of liquid metal inside the system. The present invention relates to an improvement in vapor trap to remove the metal vapor from the cover gas. The trap consists of a cylindrical outer body, an inlet nozzle which is deeply inserted inside the outer body and has a number of holes to inject the cove gas into the body, metal mesh or steel wool which covers the exterior of the nozzle and on which the condensation of the metal gas takes place, and a heater wire hich is wound around the nozzle to prevent condensation of the metal vapor at the inner peripheral side of the mesh.

  3. NONLINEAR COLOR-METALLICITY RELATIONS OF GLOBULAR CLUSTERS. II. A TEST ON THE NONLINEARITY SCENARIO FOR COLOR BIMODALITY USING THE u-BAND COLORS: THE CASE OF M87 (NGC 4486)

    International Nuclear Information System (INIS)

    Yoon, Suk-Jin; Lee, Sang-Yoon; Kim, Hak-Sub; Cho, Jaeil; Chung, Chul; Sohn, Sangmo T.; Blakeslee, John P.

    2011-01-01

    The optical color distributions of globular clusters (GCs) in most large elliptical galaxies are bimodal. Based on the assumed linear relationship between GC colors and their metallicities, the bimodality has been taken as evidence of two GC subsystems with different metallicities in each galaxy and has led to a number of theories in the context of galaxy formation. More recent observations and modeling of GCs, however, suggests that the color-metallicity relations (CMRs) are inflected, and thus colors likely trace metallicities in a nonlinear manner. The nonlinearity could produce bimodal color distributions from a broad underlying metallicity spread, even if it is unimodal. Despite the far-reaching implications, whether CMRs are nonlinear and whether the nonlinearity indeed causes the color bimodality are still open questions. Given that the spectroscopic refinement of CMRs is still very challenging, we here propose a new photometric technique to probe the possible nonlinear nature of CMRs. In essence, a color distribution of GCs is a 'projected' distribution of their metallicities. Since the form of CMRs hinges on which color is used, the shape of color distributions varies depending significantly on the colors. Among other optical colors, the u-band related colors (e.g., u – g and u – z) are theoretically predicted to exhibit significantly less inflected CMRs than other preferred CMRs (e.g., for g – z). As a case study, we performed the Hubble Space Telescope (HST)/WFPC2 archival u-band photometry for the M87 (NGC 4486) GC system with confirmed color bimodality. We show that the u-band color distributions are significantly different from that of g – z and consistent with our model predictions. With more u-band measurements, this method will support or rule out the nonlinear CMR scenario for the origin of GC color bimodality with high confidence. The HST/WFC3 observations in F336W for nearby large elliptical galaxies are highly anticipated in this regard.

  4. Chromium metal organic frameworks and synthesis of metal organic frameworks

    Science.gov (United States)

    Zhou, Hong-Cai; Liu, Tian-Fu; Lian, Xizhen; Zou, Lanfang; Feng, Dawei

    2018-04-24

    The present invention relates to monocrystalline metal organic frameworks comprising chromium ions and carboxylate ligands and the use of the same, for example their use for storing a gas. The invention also relates to methods for preparing metal organic frameworks comprising chromium, titanium or iron ions and carboxylate ligands. The methods of the invention allow such metal organic frameworks to be prepared in monocrystalline or polycrystalline forms.

  5. Metallic nanomesh

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Zhifeng; Sun, Tianyi; Guo, Chuanfei

    2018-02-20

    A transparent flexible nanomesh having at least one conductive element and sheet resistance less than 300.OMEGA./.quadrature. when stretched to a strain of 200% in at least one direction. The nanomesh is formed by depositing a sacrificial film, depositing, etching, and oxidizing a first metal layer on the film, etching the sacrificial film, depositing a second metal layer, and removing the first metal layer to form a nanomesh on the substrate.

  6. Mapping the Galvanic Corrosion of Three Metals Coupled with a Wire Beam Electrode: The Influence of Temperature and Relative Geometrical Position

    Science.gov (United States)

    Liu, Yun-Fei; Liu, Shu-Fa; Duan, Jin-Zhuo

    2018-01-01

    The local electrochemical properties of galvanic corrosion for three coupled metals in a desalination plant were investigated with three wire-beam electrodes as wire sensors: aluminum brass (HAl77-2), titanium (TA2), and 316L stainless steel (316L SS). These electrodes were used with artificial seawater at different temperatures. The potential and current–density distributions of the three-metal coupled system are inhomogeneous. The HAl77-2 wire anodes were corroded in the three-metal coupled system. The TA2 wires acted as cathodes and were protected; the 316L SS wires acted as secondary cathodes. The temperature and electrode arrangement have important effects on the galvanic corrosion of the three-metal coupled system. The corrosion current of the HAl77-2 increased with temperature indicating enhanced anode corrosion at higher temperature. In addition, the corrosion of HAl77-2 was more significant when the HAl77-2 wires were located in the middle of the coupled system than with the other two metal arrangement styles. PMID:29495617

  7. OBSERVATIONS OF BINARY STARS WITH THE DIFFERENTIAL SPECKLE SURVEY INSTRUMENT. V. TOWARD AN EMPIRICAL METAL-POOR MASS–LUMINOSITY RELATION

    International Nuclear Information System (INIS)

    Horch, Elliott P.; Van Altena, William F.; Demarque, Pierre; Howell, Steve B.; Everett, Mark E.; Ciardi, David R.; Teske, Johanna K.; Henry, Todd J.; Winters, Jennifer G.

    2015-01-01

    In an effort to better understand the details of the stellar structure and evolution of metal-poor stars, the Gemini North telescope was used on two occasions to take speckle imaging data of a sample of known spectroscopic binary stars and other nearby stars in order to search for and resolve close companions. The observations were obtained using the Differential Speckle Survey Instrument, which takes data in two filters simultaneously. The results presented here are of 90 observations of 23 systems in which one or more companions was detected, and six stars where no companion was detected to the limit of the camera capabilities at Gemini. In the case of the binary and multiple stars, these results are then further analyzed to make first orbit determinations in five cases, and orbit refinements in four other cases. The mass information is derived, and since the systems span a range in metallicity, a study is presented that compares our results with the expected trend in total mass as derived from the most recent Yale isochrones as a function of metal abundance. These data suggest that metal-poor main-sequence stars are less massive at a given color than their solar-metallicity analogues in a manner consistent with that predicted from the theory

  8. Mapping the Galvanic Corrosion of Three Metals Coupled with a Wire Beam Electrode: The Influence of Temperature and Relative Geometrical Position.

    Science.gov (United States)

    Ju, Hong; Yang, Yuan-Feng; Liu, Yun-Fei; Liu, Shu-Fa; Duan, Jin-Zhuo; Li, Yan

    2018-02-28

    The local electrochemical properties of galvanic corrosion for three coupled metals in a desalination plant were investigated with three wire-beam electrodes as wire sensors: aluminum brass (HAl77-2), titanium (TA2), and 316L stainless steel (316L SS). These electrodes were used with artificial seawater at different temperatures. The potential and current-density distributions of the three-metal coupled system are inhomogeneous. The HAl77-2 wire anodes were corroded in the three-metal coupled system. The TA2 wires acted as cathodes and were protected; the 316L SS wires acted as secondary cathodes. The temperature and electrode arrangement have important effects on the galvanic corrosion of the three-metal coupled system. The corrosion current of the HAl77-2 increased with temperature indicating enhanced anode corrosion at higher temperature. In addition, the corrosion of HAl77-2 was more significant when the HAl77-2 wires were located in the middle of the coupled system than with the other two metal arrangement styles.

  9. Mapping the Galvanic Corrosion of Three Metals Coupled with a Wire Beam Electrode: The Influence of Temperature and Relative Geometrical Position

    Directory of Open Access Journals (Sweden)

    Hong Ju

    2018-02-01

    Full Text Available The local electrochemical properties of galvanic corrosion for three coupled metals in a desalination plant were investigated with three wire-beam electrodes as wire sensors: aluminum brass (HAl77-2, titanium (TA2, and 316L stainless steel (316L SS. These electrodes were used with artificial seawater at different temperatures. The potential and current–density distributions of the three-metal coupled system are inhomogeneous. The HAl77-2 wire anodes were corroded in the three-metal coupled system. The TA2 wires acted as cathodes and were protected; the 316L SS wires acted as secondary cathodes. The temperature and electrode arrangement have important effects on the galvanic corrosion of the three-metal coupled system. The corrosion current of the HAl77-2 increased with temperature indicating enhanced anode corrosion at higher temperature. In addition, the corrosion of HAl77-2 was more significant when the HAl77-2 wires were located in the middle of the coupled system than with the other two metal arrangement styles.

  10. Corrosion-resistant metal surfaces

    Science.gov (United States)

    Sugama, Toshifumi [Wading River, NY

    2009-03-24

    The present invention relates to metal surfaces having thereon an ultrathin (e.g., less than ten nanometer thickness) corrosion-resistant film, thereby rendering the metal surfaces corrosion-resistant. The corrosion-resistant film includes an at least partially crosslinked amido-functionalized silanol component in combination with rare-earth metal oxide nanoparticles. The invention also relates to methods for producing such corrosion-resistant films.

  11. Comparative Study of Raw and Boiled Silver Pomfret Fish from Coastal Area and Retail Market in Relation to Trace Metals and Proximate Composition

    Science.gov (United States)

    Huque, Roksana; Munshi, M. Kamruzzaman; Khatun, Afifa; Islam, Mahfuza; Hossain, Afzal; Hossain, Arzina; Akter, Shirin; Kabir, Jamiul; Nahar Jolly, Yeasmin; Islam, Ashraful

    2014-01-01

    Trace metals concentration and proximate composition of raw and boiled silver pomfret (Pampus argenteus) from coastal area and retail market were determined to gain the knowledge of the risk and benefits associated with indiscriminate consumption of marine fishes. The effects of cooking (boiling) on trace metal and proximate composition of silver pomfret fish were also investigated. Trace element results were determined by the Energy Dispersive X-ray Fluorescence (EDXRF) Spectrometer wherein fish samples from both areas exceeded the standard limits set by FAO/WHO for manganese, lead, cadmiumm and chromium and boiling has no significant effects on these three metal concentrations. Long-term intake of these contaminated fish samples can pose a health risk to humans who consume them. PMID:26904650

  12. Levels of metals in kidney, liver and muscle tissue and their relation to the occurrence of parasites in the red fox in the Lower Silesian Forest in Europe.

    Science.gov (United States)

    Binkowski, Łukasz J; Merta, Dorota; Przystupińska, Anna; Sołtysiak, Zenon; Pacoń, Jarosław; Stawarz, Robert

    2016-04-01

    Together with the occurrence of parasites, increased concentrations of xenobiotics, to which scavengers are greatly exposed, may significantly influence the physiology of red foxes. It is also suspected that these two factors interact. The accumulation of various metals (Ca, Cd, Cu, Fe, Hg, K, Mg, Ni, Pb, Zn) in kidney, liver and muscle tissue was investigated, as well as the occurrence of parasites, and the potential link to the presence of metals. Generally speaking, neither sex nor age influenced these concentrations. K, Mg and Fe were found in the highest concentrations and Hg was found in the lowest. Various relationships between the concentrations of metals were observed in the tissues. 34% of the specimens studied were hosts to parasites. No clear, significant connection between the concentrations and the occurrence of parasites was noted, but the discernible trend confirmed by the logistic regression, needs further study. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Comparative Study of Raw and Boiled Silver Pomfret Fish from Coastal Area and Retail Market in Relation to Trace Metals and Proximate Composition

    Directory of Open Access Journals (Sweden)

    Roksana Huque

    2014-01-01

    Full Text Available Trace metals concentration and proximate composition of raw and boiled silver pomfret (Pampus argenteus from coastal area and retail market were determined to gain the knowledge of the risk and benefits associated with indiscriminate consumption of marine fishes. The effects of cooking (boiling on trace metal and proximate composition of silver pomfret fish were also investigated. Trace element results were determined by the Energy Dispersive X-ray Fluorescence (EDXRF Spectrometer wherein fish samples from both areas exceeded the standard limits set by FAO/WHO for manganese, lead, cadmiumm and chromium and boiling has no significant effects on these three metal concentrations. Long-term intake of these contaminated fish samples can pose a health risk to humans who consume them.

  14. Plasma metallization

    International Nuclear Information System (INIS)

    Crowther, J.M.

    1997-09-01

    Many methods are currently used for the production of thin metal films. However, all of these have drawbacks associated with them, for example the need for UHV conditions, high temperatures, exotic metal precursors, or the inability to coat complex shaped objects. Reduction of supported metal salts by non-isothermal plasma treatment does not suffer from these drawbacks. In order to produce and analyse metal films before they become contaminated, a plasma chamber which could be attached directly to a UHV chamber with XPS capability was designed and built. This allowed plasma treatment of supported metal salts and surface analysis by XPS to be performed without exposure of the metal film to the atmosphere. Non-equilibrium plasma treatment of Nylon 66 supported gold(lll) chloride using hydrogen as the feed gas resulted in a 95% pure gold film, the remaining 5% of the film being carbon. If argon or helium were used as the feed gases during plasma treatment the resultant gold films were 100% pure. Some degree of surface contamination of the films due to plasma treatment was observed but was easily removed by argon ion cleaning. Hydrogen plasma reduction of glass supported silver(l) nitrate and palladium(ll) acetate films reveals that this metallization technique is applicable to a wide variety of metal salts and supports, and has also shown the ability of plasma reduction to retain the complex 'fern-like' structures seen for spin coated silver(l) nitrate layers. Some metal salts are susceptible to decomposition by X-rays. The reduction of Nylon 66 supported gold(lll) chloride films by soft X-rays to produce nanoscopic gold particles has been studied. The spontaneous reduction of these X-ray irradiated support gold(lll) chloride films on exposure to the atmosphere to produce gold rich metallic films has also been reported. (author)

  15. Characterization of sewage sludge amended soils and related crop plants with respect to phytoavailability of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn)

    Czech Academy of Sciences Publication Activity Database

    Večeřa, Zbyněk; Dočekal, Bohumil; Marek, Petr; Sáňka, M.

    2001-01-01

    Roč. 8, 2-3 (2001), s. 243-252 ISSN 1231-7098 R&D Projects: GA MŠk OK 385 Grant - others:Copernicus(BE) ERB IC-15-CT98-0124 Institutional research plan: CEZ:AV0Z4031919 Keywords : determination of heavy metals * sewage sludge * soil analysis Subject RIV: CB - Analytical Chemistry, Separation

  16. A Longitudinal Study of Association between Heavy Metals and Itchy Eyes, Coughing in Chronic Cough Patients: Related with Non-Immunoglobulin E Mediated Mechanism

    Directory of Open Access Journals (Sweden)

    Thao Thi Thu Nguyen

    2016-01-01

    Full Text Available The association between heavy metals exposure and respiratory diseases or allergic sensitization showing high serum immunoglobulin E (IgE has been suggested. However, previous findings have been inconsistent and the mechanisms responsible remain unclear. We evaluated heavy metal exposure and its association with coughing, itchy eyes in chronic cough patients with different IgE levels. Ninety outpatients in Kanazawa University Hospital were recruited between January–June 2011. Subjects whose total IgE measured by radioimmunosorbent test were asked to record their daily symptoms. We collected daily total suspended particles (TSP from which concentrations of calcium (Ca, cadmium (Cd, chromium (Cr, iron (Fe, manganese (Mn, nickel (Ni, and lead (Pb were determined then divided into high and low level groups. Generalized estimating equations were applied to compute the relationship between concentrations of these metals and symptoms. All metals at high levels were significantly associated with itchy eyes compared with low levels, with exception of Ca, the six others were significant in patients with IgE < 250 IU/mL. Cd, Fe, Mn had association with coughing (odds ratio-OR (95% confidence interval-CI: 1.13 (1.03, 1.24, 1.22 (1.05, 1.42, and 1.13 (1.01, 1.27, respectively, this relationship remained significant for Cd (OR (95% CI: 1.14 (1.03, 1.27 and Mn (OR (95% CI: 1.15 (1.00, 1.31 in patients with lower IgE. Our findings demonstrate the relationship between aerial heavy metals and itchy eyes, coughing in chronic cough patients, suggesting these symptoms may be due to a non-IgE mediated mechanism.

  17. Dinitrogen and Related Chemistry of the Lanthanides: A Review of the Reductive Capture of Dinitrogen, As Well As Mono- and Di-aza Containing Ligand Chemistry of Relevance to Known and Postulated Metal Mediated Dinitrogen Derivatives

    Directory of Open Access Journals (Sweden)

    Damien N. Stringer

    2010-02-01

    Full Text Available This paper reviews the current array of complexes of relevance to achieving lanthanide mediated nitrogen fixation. A brief history of nitrogen fixation is described, including a limited discussion of successful transition metal facilitated nitrogen fixation systems. A detailed discussion of the numerous lanthanide-nitrogen species relevant to nitrogen fixation are discussed and are related to the Chatt cycle for nitrogen fixation.

  18. Micro metal forming

    CERN Document Server

    2013-01-01

    Micro Metal Forming, i. e. forming of parts and features with dimensions below 1 mm, is a young area of research in the wide field of metal forming technologies, expanding the limits for applying metal forming towards micro technology. The essential challenges arise from the reduced geometrical size and the increased lot size. In order to enable potential users to apply micro metal forming in production, information about the following topics are given: tribological behavior: friction between tool and work piece as well as tool wear mechanical behavior: strength and formability of the work piece material, durability of the work pieces size effects: basic description of effects occurring due to the fact, that the quantitative relation between different features changes with decreasing size process windows and limits for forming processes tool making methods numerical modeling of processes and process chains quality assurance and metrology All topics are discussed with respect to the questions relevant to micro...

  19. Genotoxicity of metal nanoparticles.

    Science.gov (United States)

    Xie, Hong; Mason, Michael M; Wise, John Pierce

    2011-01-01

    Nanotechnology is currently used in industry, medicine, and military applications, as well as in more than 300 commercial products. Yet, the same properties that make these particles exciting for technology also make them daunting public health concerns because their toxicity is unknown and relatively unexplored. Increased attention is being placed on the study of metal particle genotoxicity; however, a lot of unknowns remain about their effects and the mechanisms. In this article, we highlight some metal and metal oxide nanoparticles of interest and discuss the current in vivo and in vitro studies of genotoxic effects. Many metal nanoparticles were found to cause chromosomal aberrations, DNA strand breaks, oxidative DNA damage, and mutations. Inconsistencies are found in the literature, however, thus drawing conclusions is difficult due to a variety of factors. Therefore, the areas requiring further attention are highlighted and recommendations to improve our understanding of the genotoxic potential are addressed.

  20. Hazard assessment of metals in invasive fish species of the Yamuna River, India in relation to bioaccumulation factor and exposure concentration for human health implications.

    Science.gov (United States)

    Singh, Atul K; Srivastava, Sharad C; Verma, Pankaj; Ansari, Abubakar; Verma, Ambrish

    2014-06-01

    Monitoring of heavy metals was conducted in the Yamuna River considering bioaccumulation factor, exposure concentration, and human health implications which showed contamination levels of copper (Cu), lead (Pb), nickel (Ni), and chromium (Cr) and their dispersion patterns along the river. Largest concentration of Pb in river water was 392 μg L(-1); Cu was 392 μg L(-1) at the extreme downstream, Allahabad and Ni was 146 μg L(-1) at midstream, Agra. Largest concentration of Cu was 617 μg kg(-1), Ni 1,621 μg kg(-1) at midstream while Pb was 1,214 μg kg(-1) at Allahabad in surface sediment. The bioconcentration of Cu, Pb, Ni, and Cr was observed where the largest accumulation of Pb was 2.29 μg kg(-1) in Oreochromis niloticus and 1.55 μg kg(-1) in Cyprinus carpio invaded at Allahabad while largest concentration of Ni was 174 μg kg(-1) in O. niloticus and 124 μg kg(-1) in C. carpio in the midstream of the river. The calculated values of hazard index (HI) for Pb was found more than one which indicated human health concern. Carcinogenic risk value for Ni was again high i.e., 17.02 × 10(-4) which was larger than all other metals studied. The results of this study indicated bioconcentration in fish due to their exposures to heavy metals from different routes which had human health risk implications. Thus, regular environmental monitoring of heavy metal contamination in fish is advocated for assessing food safety since health risk may be associated with the consumption of fish contaminated through exposure to a degraded environment.

  1. Hydrogeochemical and mineralogical characteristics related to heavy metal attenuation in a stream polluted by acid mine drainage:A case study in Dabaoshan Mine, China

    Institute of Scientific and Technical Information of China (English)

    Huarong Zhao; Beicheng Xia; Jianqiao Qin; Jiaying Zhang

    2012-01-01

    Dabaoshan Mine,the largest mine in south China,has been developed since the 1970s.Acid mine drainage (AMD) discharged from the mine has caused severe environmental pollution and human health problems.In this article,chemical characteristics,mineralogy of ocher precipitations and heavy metal attenuation in the AMD are discussed based on physicochemical analysis,mineral analysis,sequential extraction experiments and hydrogeochemistry.The AMD chemical characteristics were determined from the initial water composition,water-rock interactions and dissolved sulfide minerals in the mine tailings.The waters,affected and unaffected by AMD,were Ca-SO4 and Ca-HCO3 types,respectively.The affected water had a low pH,high SO42- and high heavy metal content and oxidation as determined by the Fe2+/Fe3+ couple.Heavy metal and SO42- contents of Hengshi River water decreased,while pH increased,downstream.Schwertmannite was the major mineral at the waste dump,while goethite and quartz were dominant at the tailings dam and streambed.Schwertmannite was transformed into goethite at the tailings dam and streambed.The sulfate ions of the secondary minerals changed from bidentate- to monodentate-complexes downstream.Fe-Mn oxide phases of Zn,Cd and Pb in sediments increased downstream.However,organic matter complexes of Cu in sediments increased further away from the tailings.Fe3+ mineral precipitates and transformations controlled the AMD water chemistry.

  2. Assessing the Variability of Heavy Metal Concentrations in Liquid-Solid Two-Phase and Related Environmental Risks in the Weihe River of Shaanxi Province, China

    Science.gov (United States)

    Song, Jinxi; Yang, Xiaogang; Zhang, Junlong; Long, Yongqing; Zhang, Yan; Zhang, Taifan

    2015-01-01

    Accurate estimation of the variability of heavy metals in river water and the hyporheic zone is crucial for pollution control and environmental management. The biotoxicities and potential ecological risks of heavy metals (Cu, Zn, Pb, Cd) in a solid-liquid two-phase system were estimated using the Geo-accumulation Index, Potential Ecological Risk Assessment and Quality Standard Index methods in the Weihe River of Shaanxi Province, China. Water and sediment samples were collected from five study sites during spring, summer and winter, 2013. The dominant species in the streambed sediments were chironomids and flutter earthworm, whose bioturbation mainly ranged from 0 to 20 cm. The concentrations of heavy metals in surface water and pore water varied obviously in spring and summer. The degrees of concentration of Cu and Cd in spring and summer were higher than the U.S. water quality Criteria Maximum Concentrations. Furthermore, the biotoxicities of Pb and Zn demonstrated season-spatial variations. The concentrations of Cu, Zn, Pb and Cd in spring and winter were significantly higher than those in summer, and the pollution levels also varied obviously in different layers of the sediments. Moreover, the pollution level of Cd was the most serious, as estimated by all three assessment methods. PMID:26193293

  3. Spatial distribution and potential biological risk of some metals in relation to granulometric content in core sediments from Chilika Lake, India.

    Science.gov (United States)

    Barik, Saroja K; Muduli, Pradipta R; Mohanty, Bita; Rath, Prasanta; Samanta, Srikanta

    2018-01-01

    The article presents first systematic report on the concentration of selected major elements [iron (Fe) and manganese (Mn)] and minor elements [zinc (Zn), copper (Cu), chromium (Cr), lead (Pb), nickel (Ni), and cobalt (Co)] from the core sediment of Chilika Lake, India. The analyzed samples revealed higher content of Pb than the background levels in the entire study area. The extent of contamination from minor and major elements is expressed by assessing (i) the metal enrichments in the sediment through the calculations of anthropogenic factor (AF), pollution load index (PLI), Enrichment factor (EF), and geoaccumulation index (Igeo) and (ii) potential biological risks by the use of sediment quality guidelines like effect range median (ERM) and effect range low (ERL) benchmarks. The estimated indices indicated that sediment is enriched with Pb, Ni, Cr, Cu and Co. The enrichment of these elements seems to be due to the fine granulometric characteristics of the sediment with Fe and Mn oxyhydroxides being the main metal carriers and fishing boats using low grade paints, fuel, and fishing technology using lead beads fixed to fishing nets. Trace element input to the Chilika lake needs to be monitored with due emphasis on Cr and Pb contaminations since the ERM and ERL benchmarks indicated potential biological risk with these metals.

  4. Novel non-platinum metal catalyst material

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a novel non-platinum metal catalyst material for use in low temperature fuel cells and electrolysers and to fuel cells and electrolysers comprising the novel non-platinum metal catalyst material. The present invention also relates to a novel method for synthesizing...... the novel non-platinum metal catalyst material....

  5. Electronic structure of metallic glasses

    International Nuclear Information System (INIS)

    Oelhafen, P.; Lapka, R.; Gubler, U.; Krieg, J.; DasGupta, A.; Guentherodt, H.J.; Mizoguchi, T.; Hague, C.; Kuebler, J.; Nagel, S.R.

    1981-01-01

    This paper is organized in six sections and deals with (1) the glassy transition metal alloys, their d-band structure, the d-band shifts on alloying and their relation to the alloy heat of formation (ΔH) and the glass forming ability, (2) the glass to crystal phase transition viewed by valence band spectroscopy, (3) band structure calculations, (4) metallic glasses prepared by laser glazing, (5) glassy normal metal alloys, and (6) glassy hydrides

  6. Correlations of particle number concentrations and metals with nitrogen oxides and other traffic-related air pollutants in Glasgow and London

    Science.gov (United States)

    Sánchez Jiménez, Araceli; Heal, Mathew R.; Beverland, Iain J.

    2012-07-01

    Particle number concentration (PNC) and transition metal content are implicated in the health effects of airborne particulate matter (PM) but they are difficult to measure so consequently their temporal and spatial variations are not well characterized. Daily concentrations of PNC and particle-bound water-soluble metals (V, Cr, Mn, Fe, Ni, Cu, As, Cd and Pb) were measured at background and kerbside sites in Glasgow and London to examine if other metrics of air pollution such as optical darkness (absorbance) of collected filter samples of PM, gravimetric PM, and NO, NO2 and CO gas concentrations, can be used as surrogates for the temporal and spatial variations of the former. NO2 and NOx exhibited a high degree of within-site correlation and with PNC and water-soluble metals (Fe, Cu, As, Cd, Pb) at background sites in both cities. There is therefore potential to use NO2 and NOx as surrogates for PNC and water-soluble metal at background sites. However, correlation was weaker in complex street canyon environments where pollutant concentrations are strongly affected by local sources and the small-scale variations in pollutant dispersion induced by the wind regimes within street canyons. The corollary of the high correlation between NO2 and PNC and water-soluble metals at the background sites is that the latter pollutants may act as confounders for health effects attributed to NO2 from such sites. Concentrations of CO cannot be used as a surrogate for PNC. Increments in daily NOx and NO2 concentrations between trafficked and background sites were shown to be a simple and novel surrogate for daily spatial variation of PNC; for example, increments in NOx explained 78-79% of the variance in PNC at the paired sites in both Glasgow and London, but relationships were city specific. The increments in NOx also explained 70% of the spatial variation in Cu and Ni in Glasgow but not in London. Weekly NO2 measurements derived from passive diffusion tubes were also shown to

  7. Charging damage in floating metal-insulator-metal capacitors

    NARCIS (Netherlands)

    Ackaert, Jan; Wang, Zhichun; De Backer, E.; Coppens, P.

    2002-01-01

    In this paper, charging induced damage (CID) to metal-insulator-metal capacitors (MIMC) is reported. The damage is caused by the build up of a voltage potential difference between the two plates of the capacitor. A simple logarithmic relation is discovered between the damage by this voltage

  8. Atmospheric deposition of heavy metals in rural and urban areas of Romania studied by the moss biomonitoring technique employing nuclear and related analytical techniques and GIS technology

    International Nuclear Information System (INIS)

    Lucaciu, Adriana; Frontasyeva, Marina; Stan, Otilia; Steinnes, E.; Sasaran, N.; Cziple Katalina

    2001-01-01

    This paper presents data for 39 elements in moss samples collected in the Transylvanian Plateau of Romania. The analyses were carried out by ENAA with the exception of Cu and Pb which were determined by AAS. Extremely high values are observed for elements such as Cu, Zn, As, Cd, and Sb in parts of this territory affected by local metal industries. The levels are among the highest observed in the world, and could be partly responsible for the unfortunate health situation in some of these areas. (author)

  9. Full-scale agricultural biogas plant metal content and process parameters in relation to bacterial and archaeal microbial communities over 2.5 year span.

    Science.gov (United States)

    Repinc, Sabina Kolbl; Šket, Robert; Zavec, Domen; Mikuš, Katarina Vogel; Fermoso, Fernando G; Stres, Blaž

    2018-05-01

    A start-up of 4 MW agricultural biogas plant in Vučja vas, Slovenia, was monitored from 2011 to 2014. The start-up was carried out in 3 weeks with the intake of biomass from three operating full-scale 1-2 MW donor agricultural biogas plants. The samples were taken from donor digesters and from two serial digesters during the start-up over the course of 2.5 years. Bacterial and Archaeal microbial communities progressively diverged from the composition of donor digesters during the start-up phase. The rate of change of Bacterial community decreased exponentially over the first 2.5 years as dynamics within the first 70 days was comparable to that of the next 1.5 years, whereas approximately constant rate was observed for Archaea. Despite rearrangements, the microbial communities remained functionally stable and produced biogas throughout the whole 2.5 years of observation. All systems parameters measured were ordered according to their Kernel density (Gaussian function) ranging from the most dispersed (substrate categories used as cosubstrates, quantities of each cosubstrate, substate dry and volatile matter, process parameters) towards progressively least dispersed (trace metal and ion profiles, aromatic-polyphenolic compounds, biogas plant functional output (energy)). No deficiency was detected in trace metal content as the distribution of metals and elements fluctuated within the suggested limits for biogas over 2.5 year observation. In contrast to the recorded process variables, Bacterial and Archaeal microbial communities exhibited directed changes oriented in time. Variation partitioning showed that a large fraction of variability in the Bacterial and Archaeal microbial communities (55% and 61%, respectively) remained unexplained despite numerous measured variables (n = 44) and stable biogas production. Our results show that the observed reorganization of microbial communities was not directly associated with impact on the full-scale biogas reactor

  10. Behavior of Metals in Soils

    Science.gov (United States)

    One of the major issues of concern to the Forum is the mobility of metals in soils as related to subsurface remediation. For the purposes of this Issue Paper, those metals most commonly found at Superfund sites will be discussed in terms of the processes..

  11. Knowledge-based metals & materials

    OpenAIRE

    Sasson, Amir

    2011-01-01

    This study presents the Norwegian metal and material industry (defined as all metal and material related firms located in Norway, regardless of ownership) and evaluates the industry according to the underlying dimensions of a global knowledge hub - cluster attractiveness, education attractiveness, talent attractiveness, R&D and innovation attractiveness, ownership attractiveness, environmental attractiveness and cluster dynamics.

  12. Relationship between metal speciation in soil solution and metal adsorption at the root surface of ryegrass.

    Science.gov (United States)

    Kalis, Erwin J J; Temminghoff, Erwin J M; Town, Raewyn M; Unsworth, Emily R; van Riemsdijk, Willem H

    2008-01-01

    The total metal content of the soil or total metal concentration in the soil solution is not always a good indicator for metal availability to plants. Therefore, several speciation techniques have been developed that measure a defined fraction of the total metal concentration in the soil solution. In this study the Donnan Membrane Technique (DMT) was used to measure free metal ion concentrations in CaCl(2) extractions (to mimic the soil solution, and to work under standardized conditions) of 10 different soils, whereas diffusive gradients in thin-films (DGT) and scanning chronopotentiometry (SCP) were used to measure the sum of free and labile metal concentrations in the CaCl(2) extracts. The DGT device was also exposed directly to the (wetted) soil (soil-DGT). The metal concentrations measured with the speciation techniques are related to the metal adsorption at the root surface of ryegrass (Lolium perenne L.), to be able to subsequently predict metal uptake. In most cases the metal adsorption related pH-dependently to the metal concentrations measured by DMT, SCP, and DGT in the CaCl(2) extract. However, the relationship between metal adsorption at the root surface and the metal concentrations measured by the soil-DGT was not-or only slightly-pH dependent. The correlations between metal adsorption at the root surface and metal speciation detected by different speciation techniques allow discussion about rate limiting steps in biouptake and the contribution of metal complexes to metal bioavailability.

  13. Liquid metal heat transfer issues

    International Nuclear Information System (INIS)

    Hoffman, H.W.; Yoder, G.L.

    1984-01-01

    An alkali liquid metal cooled nuclear reactor coupled with an alkali metal Rankine cycle provides a practicable option for space systems/missions requiring power in the 1 to 100 MW(e) range. Thermal issues relative to the use of alkali liquid metals for this purpose are identified as these result from the nature of the alkali metal fluid itself, from uncertainties in the available heat transfer correlations, and from design and performance requirements for system components operating in the earth orbital microgravity environment. It is noted that, while these issues require further attention to achieve optimum system performance, none are of such magnitude as to invalidate this particular space power concept

  14. Mechanical tests imaging on metallic matrix composites. Experimental contribution to homogenization methods validation and identification of phase-related mechanical properties

    International Nuclear Information System (INIS)

    Quoc-Thang Vo

    2013-01-01

    This work is focused on a matrix/inclusion metal composite. A simple method is proposed to evaluate the elastic properties of one phase while the properties of the other phase are assumed to be known. The method is based on both an inverse homogenization scheme and mechanical field's measurements by 2D digital image correlation. The originality of the approach rests on the scale studied, i.e. the microstructure scale of material: the characteristic size of the inclusions is about few tens of microns. The evaluation is performed on standard uniaxial tensile tests associated with a long-distance microscope. It allows observation of the surface of a specimen on the microstructure scale during the mechanical stress. First, the accuracy of the method is estimated on 'perfect' mechanical fields coming from numerical simulations for four microstructures: elastic or porous single inclusions having either spherical or cylindrical shape. Second, this accuracy is estimated on real mechanical field for two simple microstructures: an elasto-plastic metallic matrix containing a single cylindrical micro void or four cylindrical micro voids arranged in a square pattern. Third, the method is used to evaluate elastic properties of αZr inclusions with arbitrary shape in an oxidized Zircaloy-4 sample of the fuel cladding of a pressurized water reactor after an accident loss of coolant accident (LOCA). In all this study, the phases are assumed to have isotropic properties. (author) [fr

  15. Soil treatment to remove uranium and related mixed radioactive heavy metal contaminants. Ninth quarterly technical and financial progress report, January 1, 1995--March 31, 1995

    International Nuclear Information System (INIS)

    1995-05-01

    The objective of this project is to design and develop a physico-chemical treatment process for the removal of uranium and heavy metals from contaminated soil to achieve target contamination levels below 35 pCi/g of soil and a target for non-radioactive heavy metals below concentration levels permissible for release of the soil. The work will involve bench-scale and pilot-scale tests, using chelation-flotation, chemical leaching and ultrasonic leaching techniques, in conjunction with cross-flow microfiltration and filter-press operations. The effectiveness of an integrated process to treat leachates generated from soil processing will be demonstrated. Process flow-sheets suitable for in-situ and ex-situ applications will be developed and preliminary costs will be provided for the soil and leachate treatment technologies. In accordance with 10CFR 600.31 (d)(i), an extension of the project period including final report submission to 31 July 1995 was made in anticipation of potential delays in receiving Fernald soil samples at Chalk River Laboratories for the planned pilot-scale verification tests. Ex-situ pilot-scale soil decontamination and leachate treatment tests using Chalk River Chemical Pit soil are nearing completion. Soil decontamination tests using Fernald Incinerator Area soil originally scheduled for February 1995 was postponed to May 1995 as result of unexpected delays in the preparation of two drums of soils (∼416 kg) by FERMCO and paperwork required to arrange for export/import licenses

  16. Complications related to conventional self-expandable metal stent insertion and internal irradiation stent insertion in patients with advanced esophageal carcinoma: an analysis of 32 cases

    International Nuclear Information System (INIS)

    Xu Xingwen; Di Haiting; Zhu Jun; Shi Jian

    2011-01-01

    Objective: To compare the occurrence of complications between conventional self-expandable metal stent and internal irradiation stent insertion in treating patients with advanced esophageal carcinomas. Methods: A total of 32 patients with advanced esophageal carcinoma were randomly divided into irradiation stent group (n=15) and conventional stent group (n=17). Internal irradiation stent loaded with 125 I seeds was employed in patients of irradiation stent group, while conventional self-expandable metal stent was used in patients of conventional stent group. After the treatment, clinical follow-up was regularly conducted. Postoperative complications such as fever, severe chest pain, cough, esophageal perforation, pneumonia, hemorrhage, stent migration and restenosis, etc. were observed. Results: No significant difference in the occurrence of fever, severe chest pain, esophageal perforation and hemorrhage existed between the two groups (P>0.05). The difference in the occurrence of long-term complications such as stent migration or restenosis between the two groups was out statistically significant (P>0.05). However, the restenosis in irradiation stent group occurred obviously much later than that in conventional stent group. Conclusion: For the treatment of advanced esophageal carcinomas, the insertion of internal irradiation esophageal stent is safe. It dose not increase the incidence of postoperative complications. Therefore, it is worth popularizing this technique in clinical practice. (authors)

  17. Evolution of the Stellar Mass–Metallicity Relation. I. Galaxies in the z ∼ 0.4 Cluster Cl0024

    Science.gov (United States)

    Leethochawalit, Nicha; Kirby, Evan N.; Moran, Sean M.; Ellis, Richard S.; Treu, Tommaso

    2018-03-01

    We present the stellar mass–stellar metallicity relationship (MZR) in the galaxy cluster Cl0024+1654 at z ∼ 0.4 using full-spectrum stellar population synthesis modeling of individual quiescent galaxies. The lower limit of our stellar mass range is M * = 109.7 M ⊙, the lowest galaxy mass at which individual stellar metallicity has been measured beyond the local universe. We report a detection of an evolution of the stellar MZR with observed redshift at 0.037 ± 0.007 dex per Gyr, consistent with the predictions from hydrodynamical simulations. Additionally, we find that the evolution of the stellar MZR with observed redshift can be explained by an evolution of the stellar MZR with the formation time of galaxies, i.e., when the single stellar population (SSP)-equivalent ages of galaxies are taken into account. This behavior is consistent with stars forming out of gas that also has an MZR with a normalization that decreases with redshift. Lastly, we find that over the observed mass range, the MZR can be described by a linear function with a shallow slope ([{Fe}/{{H}}]\\propto (0.16+/- 0.03){log}{M}* ). The slope suggests that galaxy feedback, in terms of mass-loading factor, might be mass-independent over the observed mass and redshift range.

  18. Metal cyanides

    International Nuclear Information System (INIS)

    Wells, A.F.

    1988-01-01

    From the biewpoint of general crystal T chemistry principles and on the basis of modern data the structural chemistry of metal cyanites is presented. The features of the structure of the following compounds are considered: simple ionic alkali cyanides (Li-Cs) containing CN - ions; molybdenum (4,5), tungsten (4,5), rhenium (5,6) complexes etc, where-CN group is only connected with one metal atom; covalent cyanides of cadmium and other elements in which the CN-group serves as a bridge

  19. Plume-related mantle source of super-large rare metal deposits from the Lovozero and Khibina massifs on the Kola Peninsula, Eastern part of Baltic Shield: Sr, Nd and Hf isotope systematics

    Science.gov (United States)

    Kogarko, L. N.; Lahaye, Y.; Brey, G. P.

    2010-03-01

    The two world’s largest complexes of highly alkaline nepheline syenites and related rare metal loparite and eudialyte deposits, the Khibina and Lovozero massifs, occur in the central part of the Kola Peninsula. We measured for the first time in situ the trace element concentrations and the Sr, Nd and Hf isotope ratios by LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometer) in loparite, eudialyte an in some other pegmatitic minerals. The results are in aggreement with the whole rock Sr and Nd isotope which suggests the formation of these superlarge rare metal deposits in a magmatic closed system. The initial Hf, Sr, Nd isotope ratios are similar to the isotopic signatures of OIB indicating depleted mantle as a source. This leads to the suggestion that the origin of these gigantic alkaline intrusions is connected to a deep seated mantle source—possibly to a lower mantle plume. The required combination of a depleted mantle and high rare metal enrichment in the source can be explained by the input of incompatible elements by metasomatising melts/fluids into the zones of alkaline magma generation shortly before the partial melting event (to avoid ingrowth of radiogenic isotopes). The minerals belovite and pyrochlore from the pegmatites are abnormally high in 87Sr /86Sr ratios. This may be explained by closed system isotope evolution as a result of a significant increase in Rb/Sr during the evolution of the peralkaline magma.

  20. heavy metals

    African Journals Online (AJOL)

    NICO

    aDepartment of Chemistry, Tshwane University of Technology, P.O. Box 56208, Arcadia, 0007, South Africa. bSchool of Health Systems and Public Health, Faculty of Health Sciences, ... ing the levels of toxic metals in food.15,19 Compared to ET-AAS or .... mum pressure 350 psi and maximum temperature 210 °C. The.

  1. Italian position paper on the safety analysis of liquid metal fast breeder reactors as related to sodium fires. The PEC reactor

    International Nuclear Information System (INIS)

    Gerosa, A.

    1983-01-01

    To obtain a deep understanding of physical phenomena and engineering problems connected to sodium fires, and to optimize the utilization of human and financial resources available, CNEN (now ENEA) has decided to join the French Commissariat a l'Energie Atomique (CEA) in the realization of a Franco-Italian experimental programme on sodium fires, named ESMERALDA. As for design preventions for PEC reactor (a fast flux, liquid metal cooled, fuel element testing reactor) fundamental choices were made taking into account all available knowledge, but with particular reference to the results of CEA's previous experiments on sodium fires. More detailed design analysis will be possible in the future, based on experimental results coming from the ESMERALDA programme

  2. Metal-ligand interactions

    Science.gov (United States)

    Ervin, Kent M.

    Experimental studies of the interactions of small transition-metal cluster anions with carbonyl ligands are reviewed and compared with neutral and cationic clusters. Under thermal conditions, the reaction rates of transition-metal clusters with carbon monoxide are measured as a function of cluster size. Saturation limits for carbon monoxide addition can be related to the geometric structures of the clusters. Both energy-resolved threshold collision-induced dissociation experiments and time-resolved photodissociation experiments are used to measure metal-carbonyl binding energies. For platinum and palladium trimer anions, the carbonyl binding energies are assigned to different geometric binding sites. Platinum and palladium cluster anions catalyse the oxidation of carbon monoxide to carbon dioxide in a full catalytic cycle at thermal energies.

  3. Metal-microorganism interactions

    International Nuclear Information System (INIS)

    Andres, Y.; Thouand, G.; Redercher, S.; Boualam, M.; Texier, A.Cl.; Hoeffer, R.

    1997-01-01

    The physico-chemical procedures of treating the metalliferous effluents are not always adapted to de polluting the slightly concentrated industrial wastes. An alternative idea was advanced, implying the ability of some microorganisms to fix in considerable amounts the metal ions present in aqueous solutions, possibly in a selective way. This approach has been investigated thoroughly during the last 30 years, particularly from a mechanistic point of view. The advantage of the microorganisms lies mainly in the large diversity of bacteria and in their chemical state dependent interaction with metals, as well as, in the possibilities of developing their selective and quantitative separation properties. A biomass from Mycobacterium smegmatis, an acidic alcoholic resistant bacteria, has been used to prepare a bio-sorption support allowing the preferential sorption of thorium as compared to uranium and lanthanum. These studies have been extended to biological polymers such as chitosan and to studies related to bioaccumulation mechanisms and/or to the microbial resistances towards metals

  4. Polyamorphism in metalic glass.

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, H. W.; Liu, H. Z.; Cheng, Y. Q.; Wen, J.; Lee, P.L.; Luo, W.K.; Shastri, S.D.; Ma, E.; X-Ray Science Division; Johns Hopkins Univ.; Chinese Academy of Sciences

    2007-03-01

    A metal, or an alloy, can often exist in more than one crystal structure. The face-centered-cubic and body-centered-cubic forms of iron (or steel) are a familiar example of such polymorphism. When metallic materials are made in the amorphous form, is a parallel 'polyamorphism' possible? So far, polyamorphic phase transitions in the glassy state have been observed only in glasses involving directional and open (such as tetrahedral) coordination environments. Here, we report an in situ X-ray diffraction observation of a pressure-induced transition between two distinct amorphous polymorphs in a Ce{sub 55}Al{sub 45} metallic glass. The large density difference observed between the two polyamorphs is attributed to their different electronic and atomic structures, in particular the bond shortening revealed by ab initio modeling of the effects of f-electron delocalization. This discovery offers a new perspective of the amorphous state of metals, and has implications for understanding the structure, evolution and properties of metallic glasses and related liquids. Our work also opens a new avenue towards technologically useful amorphous alloys that are compositionally identical but with different thermodynamic, functional and rheological properties due to different bonding and structural characteristics.

  5. Metal-silica sol-gel materials

    Science.gov (United States)

    Stiegman, Albert E. (Inventor)

    2002-01-01

    The present invention relates to a single phase metal-silica sol-gel glass formed by the co-condensation of a transition metal with silicon atoms where the metal atoms are uniformly distributed within the sol-gel glass as individual metal centers. Any transition metal may be used in the sol-gel glasses. The present invention also relates to sensor materials where the sensor material is formed using the single phase metal-silica sol-gel glasses. The sensor materials may be in the form of a thin film or may be attached to an optical fiber. The present invention also relates to a method of sensing chemicals using the chemical sensors by monitoring the chromatic change of the metal-silica sol-gel glass when the chemical binds to the sensor. The present invention also relates to oxidation catalysts where a metal-silica sol-gel glass catalyzes the reaction. The present invention also relates to a method of performing oxidation reactions using the metal-silica sol-gel glasses. The present invention also relates to organopolymer metal-silica sol-gel composites where the pores of the metal-silica sol-gel glasses are filled with an organic polymer polymerized by the sol-gel glass.

  6. Characterization of star-forming dwarf galaxies at 0.1 ≲z ≲ 0.9 in VUDS: probing the low-mass end of the mass-metallicity relation

    Science.gov (United States)

    Calabrò, A.; Amorín, R.; Fontana, A.; Pérez-Montero, E.; Lemaux, B. C.; Ribeiro, B.; Bardelli, S.; Castellano, M.; Contini, T.; De Barros, S.; Garilli, B.; Grazian, A.; Guaita, L.; Hathi, N. P.; Koekemoer, A. M.; Le Fèvre, O.; Maccagni, D.; Pentericci, L.; Schaerer, D.; Talia, M.; Tasca, L. A. M.; Zucca, E.

    2017-05-01

    Context. The study of statistically significant samples of star-forming dwarf galaxies (SFDGs) at different cosmic epochs is essential for the detailed understanding of galaxy assembly and chemical evolution. However, the main properties of this large population of galaxies at intermediate redshift are still poorly known. Aims: We present the discovery and spectrophotometric characterization of a large sample of 164 faint (IAB 23-25 mag) SFDGs at redshift 0.13 ≤ z ≤ 0.88 selected by the presence of bright optical emission lines in the VIMOS Ultra Deep Survey (VUDS). We investigate their integrated physical properties and ionization conditions, which are used to discuss the low-mass end of the mass-metallicity relation (MZR) and other key scaling relations. Methods: We use optical VUDS spectra in the COSMOS, VVDS-02h, and ECDF-S fields, as well as deep multi-wavelength photometry that includes HST-ACS F814W imaging, to derive stellar masses, extinction-corrected star-formation rates (SFR), and gas-phase metallicities of SFDGs. For the latter, we use the direct method and a Te-consistent approach based on the comparison of a set of observed emission lines ratios with the predictions of detailed photoionization models. Results: The VUDS SFDGs are compact (median re 1.2 kpc), low-mass (M∗ 107-109M⊙) galaxies with a wide range of star-formation rates (SFR(Hα) 10-3-101M⊙/yr) and morphologies. Overall, they show a broad range of subsolar metallicities (12 +log (O/H) =7.26-8.7; 0.04 ≲Z/Z⊙≲ 1). Nearly half of the sample are extreme emission-line galaxies (EELGs) characterized by high equivalent widths and emission line ratios indicative of higher excitation and ionization conditions. The MZR of SFDGs shows a flatter slope compared to previous studies of galaxies in the same mass range and redshift. We find the scatter of the MZR is partly explained in the low mass range by varying specific SFRs and gas fractions amongst the galaxies in our sample. In

  7. Antimicrobial Polymers with Metal Nanoparticles

    Science.gov (United States)

    Palza, Humberto

    2015-01-01

    Metals, such as copper and silver, can be extremely toxic to bacteria at exceptionally low concentrations. Because of this biocidal activity, metals have been widely used as antimicrobial agents in a multitude of applications related with agriculture, healthcare, and the industry in general. Unlike other antimicrobial agents, metals are stable under conditions currently found in the industry allowing their use as additives. Today these metal based additives are found as: particles, ions absorbed/exchanged in different carriers, salts, hybrid structures, etc. One recent route to further extend the antimicrobial applications of these metals is by their incorporation as nanoparticles into polymer matrices. These polymer/metal nanocomposites can be prepared by several routes such as in situ synthesis of the nanoparticle within a hydrogel or direct addition of the metal nanofiller into a thermoplastic matrix. The objective of the present review is to show examples of polymer/metal composites designed to have antimicrobial activities, with a special focus on copper and silver metal nanoparticles and their mechanisms. PMID:25607734

  8. Metal shadowing for electron microscopy.

    Science.gov (United States)

    Hendricks, Gregory M

    2014-01-01

    Metal shadowing of bacteria, viruses, isolated molecules, and macromolecular assemblies is another high-resolution method for observing the ultrastructure of biological specimens. The actual procedure for producing a metal shadow is relatively simple; a heavy metal is evaporated from a source at an oblique angle to the specimen. The metal atoms pile up on the surfaces that face the source, but the surfaces away from the source are shielded and receive little metal deposit, creating a "shadow." However, the process of producing biological specimens that are suitable for metal shadowing can be very complex. There are a whole host of specimen preparation techniques that can precede metal shadowing, and all provide superior preservation in comparison to air drying, a required step in negative staining procedures. The physical forces present during air drying (i.e., surface tension of the water-air interface) will literally crush most biological specimens as they dry. In this chapter I explain the development of and procedures for the production of biological specimens from macromolecular assemblies (e.g., DNA and RNA), purified isolated molecules (e.g., proteins), and isolated viruses and bacteria preparations suitable for metal shadowing. A variation on this basic technique is to rotate the specimen during the metal deposition to produce a high-resolution three-dimensional rendering of the specimen.

  9. Ter-dependent stress response systems: novel pathways related to metal sensing, production of a nucleoside-like metabolite, and DNA-processing.

    Science.gov (United States)

    Anantharaman, Vivek; Iyer, Lakshminarayan M; Aravind, L

    2012-10-30

    The mode of action of the bacterial ter cluster and TelA genes, implicated in natural resistance to tellurite and other xenobiotic toxic compounds, pore-forming colicins and several bacteriophages, has remained enigmatic for almost two decades. Using comparative genomics, sequence-profile searches and structural analysis we present evidence that the ter gene products and their functional partners constitute previously underappreciated, chemical stress response and anti-viral defense systems of bacteria. Based on contextual information from conserved gene neighborhoods and domain architectures, we show that the ter gene products and TelA lie at the center of membrane-linked metal recognition complexes with regulatory ramifications encompassing phosphorylation-dependent signal transduction, RNA-dependent regulation, biosynthesis of nucleoside-like metabolites and DNA processing. Our analysis suggests that the multiple metal-binding and non-binding TerD paralogs and TerC are likely to constitute a membrane-associated complex, which might also include TerB and TerY, and feature several, distinct metal-binding sites. Versions of the TerB domain might also bind small molecule ligands and link the TerD paralog-TerC complex to biosynthetic modules comprising phosphoribosyltransferases (PRTases), ATP grasp amidoligases, TIM-barrel carbon-carbon lyases, and HAD phosphoesterases, which are predicted to synthesize novel nucleoside-like molecules. One of the PRTases is also likely to interact with RNA by means of its Pelota/Ribosomal protein L7AE-like domain. The von Willebrand factor A domain protein, TerY, is predicted to be part of a distinct phosphorylation switch, coupling a protein kinase and a PP2C phosphatase. We show, based on the evidence from numerous conserved gene neighborhoods and domain architectures, that both the TerB and TelA domains have been linked to diverse lipid-interaction domains, such as two novel PH-like and the Coq4 domains, in different bacteria

  10. Titanium metal obtention by fused salts electrolysis

    International Nuclear Information System (INIS)

    Perillo, P.M.; Ares, Osvaldo; Botbol, Jose.

    1989-01-01

    Potassium fluorotitanate dissolved in fused sodium chloride or potassium chloride may be electrolyzed under an inert gas atmosphere. Solid electrolysis products are formed on the cathode which contains titanium metal, sodium chloride, lower fluorotitanates and small quantities of alkali metal fluorotitanate. The extraction of titanium from the electrolysis products may be carried out by aqueous leaching (removal of chloride salts of alkali metals and a certain amount of fluorotitanates). Titanium metal obtained is relatively pure. (Author)

  11. Nanotoxicity: the toxicity research progress of metal and metal-containing nanoparticles.

    Science.gov (United States)

    Ding, Lingling; Liu, Zhidong; Aggrey, Mike Okweesi; Li, Chunhua; Chen, Jing; Tong, Ling

    2015-01-01

    Along with the exuberant development of nanotechnology, a large number of nanoformulations or non materials are successfully applied in the clinics, biomedicine, cosmetics and industry. Despite some unique advantages of nanoformulations, there exist potentially worrying toxic effects, particularly those related to metal and metal-containing nanoparticles (NPs). Although various researches have been conducted to assess the metallic and metal-containing nanoparticles toxic effects, only little is known about the toxicity expressive types and evaluation, reasons and mechanisms, influencing factors and research methods of metal and metal-containing nanotoxicity. Therefore, it is of importance to acquire a better understanding of metal and metal-containing nanoparticles toxicity for medical application. This review presents a summary on the metal and metal-containing nanoparticles toxicity research progress consulting relevant literature.

  12. ISIDORE, a probe for in situ trace metal speciation based on Donnan membrane technique with related electrochemical detection part 1: Equilibrium measurements

    Energy Technology Data Exchange (ETDEWEB)

    Parat, Corinne, E-mail: corinne.parat@univ-pau.fr [Université de Pau et des Pays de l’Adour, CNRS UMR 5254, LCABIE, 64000 Pau (France); Pinheiro, J.P. [Université de Lorraine/ENSG, CNRS UMR 7360, LIEC, 54500 Nancy (France)

    2015-10-08

    This work presents the development of a new probe (ISIDORE probe) based on the hyphenation of a Donnan Membrane Technique device (DMT) to a screen-printed electrode through a flow-cell to determine the free zinc, cadmium and lead ion concentration in natural samples, such as a freshwater river. The probe displays many advantages namely: (i) the detection can be performed on-site, which avoids all problems inherent to sampling, transport and storage; (ii) the low volume of the acceptor solution implies shorter equilibration times; (ii) the electrochemical detection system allows monitoring the free ion concentration in the acceptor solution without sampling. - Highlights: • A new probe has been developed for on-site analyses of free metal ion. • A screen-printed electrode has been hyphenated to a DMT device. • Analysis time has been reduced to 6H against 36H when using a classical DMT device. • This new probe has been successfully applied on a synthetic freshwater sample.

  13. Catalytic production of metal carbonyls from metal oxides

    Science.gov (United States)

    Sapienza, Richard S.; Slegeir, William A.; Foran, Michael T.

    1984-01-01

    This invention relates to the formation of metal carbonyls from metal oxides and specially the formation of molybdenum carbonyl and iron carbonyl from their respective oxides. Copper is used here in admixed form or used in chemically combined form as copper molybdate. The copper/metal oxide combination or combined copper is utilized with a solvent, such as toluene and subjected to carbon monoxide pressure of 25 atmospheres or greater at about 150.degree.-260.degree. C. The reducing metal copper is employed in catalytic concentrations or combined concentrations as CuMoO.sub.4 and both hydrogen and water present serve as promoters. It has been found that the yields by this process have been salutary and that additionally the catalytic metal may be reused in the process to good effect.

  14. Heavy metal movement in metal-contaminated soil profiles

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhenbin; Shuman, L.M. [Univ. of Georgia, Griffin, GA (United States)

    1996-10-01

    Heavy metal movement in soil profiles is a major environmental concern because even slow transport through the soil may eventually lead to deterioration of groundwater quality. In this study, three metal-contaminated soil (Fuquay, Dothan, and Clarendon) were selected from cropland were a high-metal flue dust had been applied annually for 6 years to raise soil pH, with application ending 4 years before sampling. One uncontaminated soil (Tifton) from the same physiographic area was also sampled as a control. Soil samples were collected in 15-cm increments from the surface to 105 cm in depth. Total contents of Zn, Cd, and Pb in the soils samples were determined. To better understand metal movement in relation to metal fractions in the soil profile, soil samples were also extracted sequentially for exchangeable (EXC), organic matter (OM), Mn oxide (MNO), amorphous Fe oxide (AFEO), crystalline Fe oxide (CFEO), and residual (RES) fractions. 35 refs., 6 figs., 2 tabs.

  15. Co-ordinated research project on assessment of levels and health-effects of airborne particulate matter in mining, metal refining and metal working industries using nuclear and related analytical techniques. Report on the second research co-ordination meeting

    International Nuclear Information System (INIS)

    2000-01-01

    Overall objectives: To demonstrate the applicability of nuclear and related techniques in studies that may impact on human health, giving emphasis to the solution of problems that have been identified to be of high priority in national and international programmes for sustainable development. Specific objectives: To develop strategies and techniques for sampling of workplace airborne particulate matter (APM) and of human tissues and body fluids (hair, blood, etc.) of exposed and non-exposed persons; To development suitable analytical procedures for analysis of such types of samples, using nuclear and related analytical techniques; To carry out workplace and personal monitoring of APM and characterise the health effects of such exposure in terms of the observed elemental concentration; To carry out tissue analyses of the workers so exposed for biological monitoring and the health effects studies. Achievements: a) Specific industries not previously monitored in individual countries have been targeted in respect of pollution assessment. Some examples are: Stainless steel processing and construction; Galvanising industry; Zinc smelting operations; Mineral fertiliser industry. b) Validation of analytical techniques through quality control exercises: NAT-3 Interlaboratory comparison for the determination of trace and minor elements in urban dust artificially loaded on air filters; NAT-4 Proficiency test on selected trace elements in lyophilised urine and air filters. c) Capacity building through the establishment of new multidisciplinary teams, personnel training and laboratory expertise. d) The sampling procedures have been harmonised through: The application of the ''Gent'' sampler for APM collection, IAEA procedures and IUPAC guidelines for sampling and sample handling of hair, blood and urine. e) All participants performed surveys on targeted industries and selected pollutants. f) The scientific output of the CRP is materialised in various national and international

  16. Holographic duality: Stealing dimensions from metals

    Science.gov (United States)

    Zaanen, Jan

    2013-10-01

    Although electrically charged black holes seem remote from superconductors and strange metals in the laboratory, they might be intimately related by the holographic dualities discovered in string theory.

  17. Contaminatiom of sediment loads of the Waterwork Ružín I. by heavy metals in relation to mining sludge basins

    Directory of Open Access Journals (Sweden)

    Brehuv Ján

    2000-09-01

    Full Text Available From the results of monitoring of the quality of surface water in the Hnilec and Hornád rivers and their tributaries followed that in addition to industrial toxic substances, it were the heavy metals from localities of former and still continuing mining, treatment or metallurgic activities that significantly influence a long-term polution. The subsequent project showed a need to monitor the impact of anthropogenic activity, namely on the Waterwork (VD Ružín I. It was a task of our institution to judge the quality of sediment loads in the waterwork area.The first samples of sediment loads of the waterwork were taken in 1994. The sampling process then continued on the same places in following years. The special methods of sampling of sediment loads (sediments from the waterwork bed were worked out depending on the locality of sampling. The total analysis of obtained air-dried samples was caried out using the AAS method. The heavy metals were also analysed. In the consent with standards and requiremnts of the co-ordinator of task, the sediment deposits were assessed in consent with Decree of the Ministry of Land Managment of the Slovak Republik 531/1994-540 on the highest admissible values of harmful subsatances in land.Comparing the results of sampling we have observed that the critical values have been achieved in case of Cu. Its high values were found in the branches of Hnilec and Hornád rivers, as well sa in the branch of Opátka. The increased contents of Co are in Beliansky and Opatsky branches, at the inflow of Hnilec and Folkmarsky brook into the waterwork. The position of Hg is interesting, as it was the main contaminating element of The Hornad river and its sediments in the past. Hg is not currently present at significant quantities.The vertical sampling was also carried out in the course of research. It was proved that the content of contaminating elements in sediments of waterwork originates in the industrial activity perfomed 15

  18. Luminescence properties of Tb{sub 3}Al{sub 5}O{sub 12} garnet and related compounds synthesized by the metal organic decomposition method

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, Yuya; Nakamura, Toshihiro, E-mail: tnakamura@gunma-u.ac.jp; Adachi, Sadao, E-mail: adachi@gunma-u.ac.jp

    2017-03-15

    The Tb–Al–O ternay compounds were prepared by the metal organic decompostion (MOD) method from mixted solutions of Al{sub 2}O{sub 3} and Tb{sub 4}O{sub 7} and subsequent calcination at T{sub c}=1200 °C in air. The structural and optical properties of the synthesized compounds were examined using X-ray diffraction analysis, photoluminescence (PL) analysis, PL excitation (PLE) spectroscopy, PL decay kinetics, and diffuse reflectance spetrosopy. The stoichiometric compounds of terbium aluminium garnet Tb{sub 3}Al{sub 5}O{sub 12} (TAG) and peroviskite-type TbAlO{sub 3} were synthesized at molar ratios of x=0.375 and 0.5 [x ≡Tb{sub 4}O{sub 7}/(Tb{sub 4}O{sub 7}+2Al{sub 2}O{sub 3})], together with the end-point binary materials of rhombohedral Al{sub 2}O{sub 3} (α-Al{sub 2}O{sub 3}; x=0) and cubic Tb{sub 4}O{sub 7} (x=1.0). One can also expect synthesis of stoichiometric compounds Tb{sub 4}Al{sub 2}O{sub 9} and Tb{sub 3}AlO{sub 12} at x=0.667 and 0.75, respectively; however, these compounds were found to be very difficult to synthesize by the MOD method or, probably by other methods. Temperature dependence of the PL spectra for TAG was measured from T=20–440 K in 10-K step and analyzed using a newly developed theoretical model. Raman scattering measurements were also performed on the Tb–Al–O material system with compositions widely varying from x=0 (α-Al{sub 2}O{sub 3}) to 1.0 (Tb{sub 4}O{sub 7}).

  19. The use of nuclear and related techniques for the studies of possible health impact of airborne particulate matter in a metal industry

    International Nuclear Information System (INIS)

    Djojosubroto, Harjoto; Supriatna, Dadang; Kumolowati, Endang; Widjajakusuma, Benjamin

    2000-01-01

    Various processes in an industry may produce gases and fine airborne particulate matters. Elements and hazardous chemicals in the fine particulate matters may enter the human body through inhalation and direct contact with the skin. Excessive inhalation and contact with the fine airborne particulate matter may lead to intoxication due to excessive intake of the hazardous chemicals and toxic elements. The elements will be accumulated in human organs, such as liver, kidneys and brain, manifest in clinical syndromes such as hypertension, renal failure and neurological symptoms and signs. The absorbed elements are excreted through the urinary tract as urine. They also can be excreted through hair and nails. Elevated blood and urinary aluminum levels have been observed after occupational exposure to various aluminum compounds. This phenomenon indicates the absorption through inhalation, as there are no data indicating significant dermal absorption for aluminum. Absorption of chromium compounds in the workplace occurs mainly through inhalation. The absorption is dependent on the valence and solubility of the particular chromium species. Some elements such as trivalent chromium ions are readily cleared from the blood, but hexavalent chromium ions are retained much longer in the blood. The aluminum compounds vary greatly in their toxic and carcinogenic effects. Although the trivalent chromium is readily excreted, continuous intake may cause the blood chromium level to be higher than normal. These elements may either have an deleterious effect on, or be considered essential for human health. In this study, the levels and health effects of airborne particulate matter in the workplace are assessed by elemental quantification of blood, hair and nail of workers in a metal industry and in airborne particulate samples that are collected at the workplace. The present report represents progress of activities following the first Research Co-ordination Meeting 1997 in Vienna

  20. Superconductivity in transition metals.

    Science.gov (United States)

    Slocombe, Daniel R; Kuznetsov, Vladimir L; Grochala, Wojciech; Williams, Robert J P; Edwards, Peter P

    2015-03-13

    A qualitative account of the occurrence and magnitude of superconductivity in the transition metals is presented, with a primary emphasis on elements of the first row. Correlations of the important parameters of the Bardeen-Cooper-Schrieffer theory of superconductivity are highlighted with respect to the number of d-shell electrons per atom of the transition elements. The relation between the systematics of superconductivity in the transition metals and the periodic table high-lights the importance of short-range or chemical bonding on the remarkable natural phenomenon of superconductivity in the chemical elements. A relationship between superconductivity and lattice instability appears naturally as a balance and competition between localized covalent bonding and so-called broken covalency, which favours d-electron delocalization and superconductivity. In this manner, the systematics of superconductivity and various other physical properties of the transition elements are related and unified. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  1. Therapy of metal poisoning

    International Nuclear Information System (INIS)

    Lindenbaum, A.

    1975-01-01

    The following studies were conducted: physical character of lead acetate and other toxic metal compounds as related to tissue distribution, toxicity, and therapeutic removal; interactions of monomeric plutonium with specific components of mouse liver and skeleton; metabolism and therapeutic decorporation of plutonium in mice and dogs; comparative studies of tissue distribution of plutonium isotopes; and microdistribution of monomeric and polymeric plutonium in beagle liver and bone

  2. Intracellular delivery of nanomaterials for sub-cellular imaging and tracking of biomolecules

    Science.gov (United States)

    Medepalli, Krishna Kiran

    Nanomaterials have many intriguing applications in biology and medicine. Unique properties such as enhanced electrical properties, increased chemical reactivity and resistance to degradation, novel optical properties and comparable size to that of biological systems have led to their use in various biomedical applications. The most important applications of nanomaterials for medicine are in drug delivery and imaging. This research focuses on utilizing the biocompatibility of single walled Carbon nanotubes (SWCNTs) and optical properties colloidal quantum dots (QDs) for cellular drug delivery and imaging of biomolecules. The first part of this research deals with single walled carbon nanotubes which are excellent candidates for targeted drug delivery applications due their unique structural and functional properties. However, prior to their use in therapeutics, their biocompatibility needs to be thoroughly investigated. The objectives of this research were to establish the biocompatibility of SWCNTs and demonstrate their use as drug delivery carriers into cells. Blood, a living tissue, is chosen as the biological system as it contains various cells which can potentially interact with SWCNTs during the delivery mechanism. The interactions of these cells in the blood (specifically white blood cells or leukocytes) with the SWCNTs provide vital information regarding the immune response of the host to the nanotubes. This research investigates the immune response of white blood cells due to SWCNTs via (a) direct interaction---presence of nanotubes in the blood and, (b) indirect interaction---presentation of nanotubes by antigen-presenting-cells to white blood cells. These two interactions recreate the innate and adaptive immune responses occurring in the body to any foreign substance. SWCNTs are functionalized with single stranded DNA (ss-DNA), which serves as a dispersant of nanotubes as well as a backbone for further attachment of other biomolecules of interest. Confocal microscopy and flow cytometric studies are performed to characterize the interactions. Results from this acute immune response study demonstrate the biocompatibility of SWCNTs in whole blood and also confirm the cellular delivery of single stranded DNA. The second part of the research is on colloidal quantum dots (QDs): nanometer sized semiconductor crystals typically between 1 nm to 20 nm in diameter. In addition to being size comparable with many biological systems, and having large surface area for multiple biomolecules attachment, they possess high resistance to chemical and photo degradation, tunable emission based on size and composition which makes them excellent candidates for cellular delivery and imaging. The main objectives of this research was to demonstrate the use of QDs for cellular imaging as well as targeted biomolecule delivery by conjugating the QDs with an antibody to a functional protein and delivery into live cells. Conventional techniques deliver QDs as aggregates, however, a major challenge in the use of QDs for cellular imaging and biomolecule delivery is achieving freely dispersed QDs inside the cells. In this research, a new technique to deliver monodispersed QDs inside live cells was developed. The approach combines osmosis driven fluid transport into cells achieved by creating hypotonic environment and reversible permeabilization using low concentrations of cell permeabilization agents like Saponin. The results confirm that highly efficient endocytosis-free intracellular delivery of QDs can be accomplished using this method. Confocal microscopy is used to image the QDs inside the cells and flow cytometry is used for quantifying the fluorescence. To demonstrate targeted delivery, QDs are conjugated to the antibody of a protein: the nuclear transcriptional factor, NFkB (Nuclear Factor kappa-light chain-enhancer of activated B cells) using EDC/sulfo NHS chemistry methods. NFkB is a family of proteins with 5 different subunits and is involved in a variety of biological processes such as immune and inflammatory responses and cellular developmental processes. In unstimulated cells, NFkB is inactive in cytoplasm and translocates to the nucleus upon stimulation using bacterial products, viruses, radiation, and the like. QDs fluorescence could be used to monitor NFKB activity over extended periods of time in live cells.

  3. Agent-Based Modeling of Mitochondria Links Sub-Cellular Dynamics to Cellular Homeostasis and Heterogeneity.

    Directory of Open Access Journals (Sweden)

    Giovanni Dalmasso

    Full Text Available Mitochondria are semi-autonomous organelles that supply energy for cellular biochemistry through oxidative phosphorylation. Within a cell, hundreds of mobile mitochondria undergo fusion and fission events to form a dynamic network. These morphological and mobility dynamics are essential for maintaining mitochondrial functional homeostasis, and alterations both impact and reflect cellular stress states. Mitochondrial homeostasis is further dependent on production (biogenesis and the removal of damaged mitochondria by selective autophagy (mitophagy. While mitochondrial function, dynamics, biogenesis and mitophagy are highly-integrated processes, it is not fully understood how systemic control in the cell is established to maintain homeostasis, or respond to bioenergetic demands. Here we used agent-based modeling (ABM to integrate molecular and imaging knowledge sets, and simulate population dynamics of mitochondria and their response to environmental energy demand. Using high-dimensional parameter searches we integrated experimentally-measured rates of mitochondrial biogenesis and mitophagy, and using sensitivity analysis we identified parameter influences on population homeostasis. By studying the dynamics of cellular subpopulations with distinct mitochondrial masses, our approach uncovered system properties of mitochondrial populations: (1 mitochondrial fusion and fission activities rapidly establish mitochondrial sub-population homeostasis, and total cellular levels of mitochondria alter fusion and fission activities and subpopulation distributions; (2 restricting the directionality of mitochondrial mobility does not alter morphology subpopulation distributions, but increases network transmission dynamics; and (3 maintaining mitochondrial mass homeostasis and responding to bioenergetic stress requires the integration of mitochondrial dynamics with the cellular bioenergetic state. Finally, (4 our model suggests sources of, and stress conditions amplifying, cell-to-cell variability of mitochondrial morphology and energetic stress states. Overall, our modeling approach integrates biochemical and imaging knowledge, and presents a novel open-modeling approach to investigate how spatial and temporal mitochondrial dynamics contribute to functional homeostasis, and how subcellular organelle heterogeneity contributes to the emergence of cell heterogeneity.

  4. Understanding radiation damage on sub-cellular scale using RADAMOL simulation tool

    Czech Academy of Sciences Publication Activity Database

    Štěpán, Václav; Davídková, Marie

    2016-01-01

    Roč. 128, NOV (2016), s. 11-17 ISSN 0969-806X R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk LD12008 Grant - others:GA MŠk(CZ) LM2010005 Institutional support: RVO:61389005 Keywords : charged particles * DNA * proteins * radiation damage * radical attack * water radiolysis Subject RIV: BO - Biophysics Impact factor: 1.315, year: 2016

  5. Sub-cellular distribution of two salt-induced peptides in roots of ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-09-15

    Sep 15, 2009 ... INTRODUCTION. Plants in their natural environment are subject to a num- .... plasma membrane (PM) components using the method of. Hodges and Mills ... the plant cell there are various compartments, to which ions may be ...

  6. Apparatus and method for measuring single cell and sub-cellular photosynthetic efficiency

    Science.gov (United States)

    Davis, Ryan Wesley; Singh, Seema; Wu, Huawen

    2013-07-09

    Devices for measuring single cell changes in photosynthetic efficiency in algal aquaculture are disclosed that include a combination of modulated LED trans-illumination of different intensities with synchronized through objective laser illumination and confocal detection. Synchronization and intensity modulation of a dual illumination scheme were provided using a custom microcontroller for a laser beam block and constant current LED driver. Therefore, single whole cell photosynthetic efficiency, and subcellular (diffraction limited) photosynthetic efficiency measurement modes are permitted. Wide field rapid light scanning actinic illumination is provided for both by an intensity modulated 470 nm LED. For the whole cell photosynthetic efficiency measurement, the same LED provides saturating pulses for generating photosynthetic induction curves. For the subcellular photosynthetic efficiency measurement, a switched through objective 488 nm laser provides saturating pulses for generating photosynthetic induction curves. A second near IR LED is employed to generate dark adapted states in the system under study.

  7. Assessment of natural and artificial radioactivity levels and radiation hazards and their relation to heavy metals in the industrial area of Port Said city, Egypt.

    Science.gov (United States)

    Attia, T E; Shendi, E H; Shehata, M A

    2015-02-01

    A detailed gamma ray spectrometry survey was carried out to make an action in environmental impact assessment of urbanization and industrialization on Port Said city, Egypt. The concentrations of the measured radioelements U-238, Th-232 in ppm, and K-40 %, in addition to the total counts of three selected randomly dumping sites (A, B, and C) were mapped. The concentration maps represent a base line for the radioactivity in the study area in order to detect any future radioactive contamination. These concentrations are ranging between 0.2 and 21 ppm for U-238 and 0.01 to 13.4 ppm for Th-232 as well as 0.15 to 3.8 % for K-40, whereas the total count values range from 8.7 to 123.6 uR. Moreover, the dose rate was mapped using the same spectrometer and survey parameters in order to assess the radiological effect of these radioelements. The dose rate values range from 0.12 to 1.61 mSv/year. Eighteen soil samples were collected from the sites with high radioelement concentrations and dose rates to determine the activity concentrations of Ra-226, Th-232, and K-40 using HPGe spectrometer. The activity concentrations of Ra-226, Th-232, and K-40 in the measured samples range from 18.03 to 398.66 Bq kg(-1), 5.28 to 75.7 Bq kg(-1), and 3,237.88 to 583.12 Bq kg(-1), respectively. In addition to analyze heavy metal for two high reading samples (a 1 and a 10) which give concentrations of Cd and Zn elements (a 1 40 ppm and a 10 42 ppm) and (a 1 0.90 ppm and a 10 0.97 ppm), respectively, that are in the range of phosphate fertilizer products that suggested a dumped man-made waste in site A. All indicate that the measured values for the soil samples in the two sites of three falls within the world ranges of soil in areas with normal levels of radioactivity, while site A shows a potential radiological risk for human beings, and it is important to carry out dose assessment program with a specifically detailed monitoring program periodically.

  8. Metal sorption on kaolinite

    International Nuclear Information System (INIS)

    Westrich, H.R.; Brady, P.V.; Cygan, R.T.; Nagy, K.L.; Anderson, H.L.

    1997-01-01

    A key issue in performance assessment of low-level radioactive waste sites is predicting the transport and retardation of radionuclides through local soils under a variety of hydrologic and geochemical conditions. Improved transport codes should include a mechanistic model of radionuclide retardation. The authors have been investigating metal sorption (Cs + , Sr 2+ , and Ba 2+ ) on a simple clay mineral (kaolinite) to better understand the geochemical interactions of common soil minerals with contaminated groundwaters. These studies include detailed characterizations of kaolinite surfaces, experimental adsorption measurements, surface complexation modeling, and theoretical simulations of cation sorption. The aluminol edge (010) site has been identified as the most likely site for metal sorption on kaolinite in natural solutions. Relative metal binding strengths decrease from Ba 2+ to Sr 2+ to Cs + , with some portion sorbed on both kaolinite edges and basal surfaces. Some Cs + also appears to be irreversibly sorbed on both sites. Molecular dynamics simulations suggest that Cs + is sorbed at aluminol (010) edge sites as an inner-sphere complex and weakly sorbed as an outer-sphere complex on (001) basal surfaces. These results provide the basis to understand and predict metal sorption onto kaolinite, and a framework to characterize sorption processes on more complex clay minerals

  9. Nature of low dimensional structural modulations and relative phase stability in RexMo(W)1-xS2 transition metal dichalcogenide alloys

    KAUST Repository

    Sahu, R.; Bhat, U.; Batra, Nitin M; Sharona, H.; Vishal, B.; Sarkar, S.; Devi, Assa Aravindh Sasikala; Peter, S. C.; Roqan, Iman S.; Costa , P. M. F. J.; Datta, Ranjan

    2017-01-01

    We report on the various types of Peierls like two dimensional structural modulations and relative phase stability of 2H and 1T poly-types in the RexMo1-xS2 and RexW1-xS2 alloy system. Theoretical calculation predicts a polytype phase transition

  10. Challenges Related to the Use of Liquid Metal and Molten Salt Coolants in Advanced Reactors. Report of the collaborative project COOL of the International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO)

    International Nuclear Information System (INIS)

    2013-05-01

    The International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) was launched in 2000, based on a resolution by the IAEA General Conference (GC(44)/RES/21). INPRO aims at helping to ensure that nuclear energy is available in the twenty-first century in a sustainable manner, and seeks to bring together all interested Member States, both technology holders and technology users, to jointly consider actions to achieve desired innovations. INPRO is taking care of the specific needs of developing countries. One of the aims of INPRO is to develop options for enhanced sustainability through promotion of technical and institutional innovations in nuclear energy technology through collaborative projects among IAEA Member States. Collaboration among INPRO members is fostered on selected innovative nuclear technologies to bridge technology gaps. Collaborative projects have been selected so that they complement other national and international R and D activities. The INPRO Collaborative Project COOL on Investigation of Technological Challenges Related to the Removal of Heat by Liquid Metal and Molten Salt Coolants from Reactor Cores Operating at High Temperatures investigated the technological challenges of cooling reactor cores that operate at high temperatures in advanced fast reactors, high temperature reactors and accelerator driven systems by using liquid metals and molten salts as coolants. The project was initiated in 2008 and was led by India; experts from Brazil, China, Germany, India, Italy and the Republic of Korea participated and provided chapters of this report. The INPRO Collaborative Project COOL addressed the following fields of research regarding liquid metal and molten salt coolants: (i) survey of thermophysical properties; (ii) experimental investigations and computational fluid dynamics studies on thermohydraulics, specifically pressure drop and heat transfer under different operating conditions; (iii) monitoring and control of coolant

  11. Study on Concentration of Particulate Matter with Diameter Less than 10 Microns, Heavy Metals and Polycyclic Aromatic Hydrocarbons Related to PM2.5 in the Ambient Air of Sina Hospital District

    Directory of Open Access Journals (Sweden)

    Majid Kermani

    2014-03-01

    Full Text Available Background:In recent decades, extensive studies have shown a number of short and long-term health effects of particle matters. In addition to particle matters, polycyclic aromatic hydrocarbons (PAHs and heavy metals in airborne particles due to their mutagenic and carcinogenic properties are considered major air pollutants. So, the aim of this study was to evaluate the concentration of PM2.5particulate, 7heavy metal concentrations and 13 PAHs compound associated with fine particles (PM2.5-boud PAHs in the district of Sina hospital, Tehran. Methods: This cross-sectional study was carried out in air of Sina Hospital district in Tehran. Concentrations of fine particulate matter (PM2.5 were determined by gravimetric. Also heavy metal concentrations in samples after digestion were determined with ICP-AES instrument through injection. Then the PAHs compounds from each sample were extracted by ultrasonic method. After this step, extracted sample was injected for analysis by GC-MS and concentration of each compound was read. Results: The daily average concentration of PM2.5 during the study was 41.19 µg/m3.Concentration values for zinc, lead, cadmium, chromium, nickel and arsenic, were 92/69, 05/38, 2/18, 24/4, 19/4 and 34/1 ng/m3 respectively but mercury not found in this study. Average concentrations of PAHs compounds have been variable from0.07 ng/m3 for Chrysene to 1.21ng/m3 for Dibenzo(ahanthracene. Conclusion: In this study, the daily average of PM2.5 concentrations was above the Iranian National PM, WHO (25 µg/m3 and EPA (35 µg/m3 standards established for PM2.5 particles. Heavy metal concentrations in this study were lower than values reported in previous studies in Tehran. The highest concentrations among PAHs compounds belonging toIndeo(cd 1,2,3pyren, Dibenzo(ah anthracene, Benzo (B flouranthin and Benzo (Kflouranthin that all of these compounds are related to vehicle emissions.

  12. Durability of metals from archaeological objects, metal meteorites, and native metals

    International Nuclear Information System (INIS)

    Johnson, A.B. Jr.; Francis, B.

    1980-01-01

    Metal durability is an important consideration in the multi-barrier nuclear waste storage concept. This study summarizes the ancient metals, the environments, and factors which appear to have contributed to metal longevity. Archaeological and radiochemical dating suggest that human use of metals began in the period 6000 to 7000 BC. Gold is clearly the most durable, but many objects fashioned from silver, copper, bronze, iron, lead, and tin have survived for several thousand years. Dry environments, such as tombs, appear to be optimum for metal preservation, but some metals have survived in shipwrecks for over a thousand years. The metal meteorites are Fe-base alloys with 5 to 60 wt% Ni and minor amounts of Co, I, and S. Some meteoritic masses with ages estimated to be 5,000 to 20,000 years have weathered very little, while other masses from the same meteorites are in advanced stages of weathering. Native metals are natural metallic ores. Approximately five million tonnes were mined from native copper deposits in Michigan. Copper masses from the Michigan deposits were transported by the Pleistocene glaciers. Areas on the copper surfaces which appear to represent glacial abrasion show minimal corrosion. Dry cooling tower technology has demonstrated that in pollution-free moist environments, metals fare better at temperatures above than below the dewpoint. Thus, in moderate temperature regimes, elevated temperatures may be useful rather than detrimental for exposures of metal to air. In liquid environments, relatively complex radiolysis reactions can occur, particularly where multiple species are present. A dry environment largely obviates radiolysis effects

  13. Durability of metals from archaeological objects, metal meteorites, and native metals

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, A.B. Jr.; Francis, B.

    1980-01-01

    Metal durability is an important consideration in the multi-barrier nuclear waste storage concept. This study summarizes the ancient metals, the environments, and factors which appear to have contributed to metal longevity. Archaeological and radiochemical dating suggest that human use of metals began in the period 6000 to 7000 BC. Gold is clearly the most durable, but many objects fashioned from silver, copper, bronze, iron, lead, and tin have survived for several thousand years. Dry environments, such as tombs, appear to be optimum for metal preservation, but some metals have survived in shipwrecks for over a thousand years. The metal meteorites are Fe-base alloys with 5 to 60 wt% Ni and minor amounts of Co, I, and S. Some meteoritic masses with ages estimated to be 5,000 to 20,000 years have weathered very little, while other masses from the same meteorites are in advanced stages of weathering. Native metals are natural metallic ores. Approximately five million tonnes were mined from native copper deposits in Michigan. Copper masses from the Michigan deposits were transported by the Pleistocene glaciers. Areas on the copper surfaces which appear to represent glacial abrasion show minimal corrosion. Dry cooling tower technology has demonstrated that in pollution-free moist environments, metals fare better at temperatures above than below the dewpoint. Thus, in moderate temperature regimes, elevated temperatures may be useful rather than detrimental for exposures of metal to air. In liquid environments, relatively complex radiolysis reactions can occur, particularly where multiple species are present. A dry environment largely obviates radiolysis effects.

  14. Are Vicinal Metal Surfaces Stable?

    DEFF Research Database (Denmark)

    Frenken, J. W. M.; Stoltze, Per

    1999-01-01

    We use effective medium theory to demonstrate that the energies of many metal surfaces are lowered when these surfaces are replaced by facets with lower-index orientations. This implies that the low-temperature equilibrium shapes of many metal crystals should be heavily faceted. The predicted...... instability of vicinal metal surfaces is at variance with the almost generally observed stability of these surfaces. We argue that the unstable orientations undergo a defaceting transition at relatively low temperatures, driven by the high vibrational entropy of steps....

  15. Relationship between the nuclear resonance of cobalt metal and its ferromagnetic properties; Relations entre la resonance nucleaire du cobalt metallique et ses proprietes ferromagnetiques

    Energy Technology Data Exchange (ETDEWEB)

    Aubrun, J.N. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-05-15

    Theoretical study of nuclear magnetic resonance in ferromagnetic metals shows the near dependence of ferromagnetic properties and unusual feature of this nuclear resonance. This results from a strong interaction between nuclei and magnetic electrons. They excite the nuclei, and, in Bloch walls, submit them to a RF field much stronger than those directly applied. The parameters of the resonance are determined from wall movement and depend consequently of ferromagnetic constants. The theory is enable to provide quantitatively some peculiar effects, specially those of a continuous magnetic field and of temperature. Experimental study was made on cobalt powders, and is in good agreement with theory. However one must take the skin-effect into consideration and accordingly adjust, the theory. This can explain some observed divergences, as well as the influence at particles size and magnetic field over the line shape. Original informations have been obtained about some typical ferromagnetic properties of cobalt, when studying magnetic field effect, and it has been able to apply this method to other ferromagnetic materials. In consideration of the peculiar characteristics of this nuclear resonance, which occurs without external magnetic field and whose line width is large, new models of spectrographs have been realized and have permitted accurate measures of the line shape. The weak intensity of the signals obtained in some cases, has induced the elaboration of an original method of extraction whose theory and practical uses are described here. The whole of this experiment reveals the nuclear resonance as a strong way for the study of ferromagnetism, which is able to detect microscopic phenomenons, not easily accessible by classical methods. (author) [French] L'etude theorique de la resonance magnetique nucleaire dans les metaux ferromagnetiques revele l'etroite liaison entre les proprietes ferromagnetiques et l'aspect inhabituel de cette resonance. Ceci

  16. Relationship between the nuclear resonance of cobalt metal and its ferromagnetic properties; Relations entre la resonance nucleaire du cobalt metallique et ses proprietes ferromagnetiques

    Energy Technology Data Exchange (ETDEWEB)

    Aubrun, J N [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-05-15

    Theoretical study of nuclear magnetic resonance in ferromagnetic metals shows the near dependence of ferromagnetic properties and unusual feature of this nuclear resonance. This results from a strong interaction between nuclei and magnetic electrons. They excite the nuclei, and, in Bloch walls, submit them to a RF field much stronger than those directly applied. The parameters of the resonance are determined from wall movement and depend consequently of ferromagnetic constants. The theory is enable to provide quantitatively some peculiar effects, specially those of a continuous magnetic field and of temperature. Experimental study was made on cobalt powders, and is in good agreement with theory. However one must take the skin-effect into consideration and accordingly adjust, the theory. This can explain some observed divergences, as well as the influence at particles size and magnetic field over the line shape. Original informations have been obtained about some typical ferromagnetic properties of cobalt, when studying magnetic field effect, and it has been able to apply this method to other ferromagnetic materials. In consideration of the peculiar characteristics of this nuclear resonance, which occurs without external magnetic field and whose line width is large, new models of spectrographs have been realized and have permitted accurate measures of the line shape. The weak intensity of the signals obtained in some cases, has induced the elaboration of an original method of extraction whose theory and practical uses are described here. The whole of this experiment reveals the nuclear resonance as a strong way for the study of ferromagnetism, which is able to detect microscopic phenomenons, not easily accessible by classical methods. (author) [French] L'etude theorique de la resonance magnetique nucleaire dans les metaux ferromagnetiques revele l'etroite liaison entre les proprietes ferromagnetiques et l'aspect inhabituel de cette resonance. Ceci resulte du

  17. Rare earth metal alloy magnets

    International Nuclear Information System (INIS)

    Harris, I.R.; Evans, J.M.; Nyholm, P.S.

    1979-01-01

    This invention relates to rare earth metal alloy magnets and to methods for their production. The technique is based on the fact that rare earth metal alloys (for e.g. cerium or yttrium) which have been crumbled to form a powder by hydride formation and decomposition can be used for the fabrication of magnets without the disadvantages inherent in alloy particle size reduction by mechanical milling. (UK)

  18. LIQUID METAL COMPOSITIONS CONTAINING URANIUM

    Science.gov (United States)

    Teitel, R.J.

    1959-04-21

    Liquid metal compositions containing a solid uranium compound dispersed therein is described. Uranium combines with tin to form the intermetallic compound USn/sub 3/. It has been found that this compound may be incorporated into a liquid bath containing bismuth and lead-bismuth components, if a relatively small percentage of tin is also included in the bath. The composition has a low thermal neutron cross section which makes it suitable for use in a liquid metal fueled nuclear reactor.

  19. METHOD OF DISSOLVING URANIUM METAL

    Science.gov (United States)

    Slotin, L.A.

    1958-02-18

    This patent relates to an economicai means of dissolving metallic uranium. It has been found that the addition of a small amount of perchloric acid to the concentrated nitric acid in which the uranium is being dissolved greatly shortens the time necessary for dissolution of the metal. Thus the use of about 1 or 2 percent of perchioric acid based on the weight of the nitric acid used, reduces the time of dissolution of uranium by a factor of about 100.

  20. Metal Contacts to Gallium Arsenide.</