Sample records for cadmium iron manganese

  1. Effect of dietary phytic acid and cadmium on the availability of cadmium, zinc, copper, iron, and manganese to rats

    SciTech Connect

    Turecki, T.; Ewan, R.C.; Stahr, H.M. [Iowa State Univ., Ames, IA (United States)

    1995-05-01

    The main route of cadmium intake for general population, both human and animal, is via ingestion. The intestinal absorption of cadmium is relatively low, 6% of a single oral dose for humans and less than 2% for various animal species. However, due to poor excretion, accumulation of cadmium occurs, primarily in kidney. The chronic exposure even to low levels of dietary cadmium can lead to the development of renal disturbances. Fox (1988) suggests that phytic acid might be a dietary component capable to influence the intestinal absorption of cadmium. Phytic acid naturally occurs as the major phosphorus storage constituent of most cereals, legumes, and oilseeds. At physiological pH, phytic acid is ionized and has a strong affinity for divalent cations. The potential of phytic acid to decrease the availability of Zn has been for long time of concern for nutritionists. Phytic acid has also been reported to decrease the availability of other trace metals. For nonessential elements, reduced availability of lead has been observed. The experimental data concerning the effect of dietary phytic acid on the availability of dietary cadmium are limited to the work of Rose and Quarterman (1984). The objective of this experiment was to examine: (1) the effect of dietary phytic acid on the availability of cadmium under conditions of chronic dietary exposure of rats to cadmium, and (2) the effect of dietary phytic acid and of chronic dietary exposure to cadmium on the availability of zinc, copper, iron, and manganese to rats. 19 refs., 4 tabs.

  2. Iron, manganese, cadmium, chromium, zinc and arsenic groundwater contents of Agbor and Owa communities of Nigeria.

    PubMed

    Oyem, Hector Henry; Oyem, Ifeanyi Mirian; Usese, Amii Isaac

    2015-01-01

    Iron, manganese, zinc, cadmium, and chromium heavy metals and arsenic contents of groundwater in area and surrounding environment, of Ika land in the Delta state, Nigeria was studied. Groundwater without any treatment is the predominant source of drinking water by inhabitants of these communities. However, the quality of this water source is not immediately known, raising questions of its safety. Results of a regional composite of groundwater obtained, shows high iron (27%) and zinc (36%) contents in Boji-Boji Agbor area, manganese (31%) was highest in Boji-Boji Owa. Alihame recorded the lowest value of zinc (8%), while manganese was lowest in Agbor Obi area (12%). Arsenic, cadmium, and chromium were below detection limit in all the sample sites. Correlational matrix analysis revealed no significant relationships between metal types studied. Analyses of chronic daily dose intake (CDI), and hazard index were all very low. A hazard index of 0.01 was obtained. One-way ANOVA show significant statistical difference in the mean concentrations of the heavy metals for the different sample sites, which indicate that different sites contribute differently to the mean concentrations of the groundwater in the study area. Four conclusions are drawn from this study. Indications are that the heavy metals present in the Nigerian aquifer are very much below the maximum concentration levels and guideline values of national and WHO standards. Secondly, there is a heavier load of these metals in the city centre than in the suburbs; with Boji-Boji area Agbor/Owa urban areas accounting for 27 and 20 percent of load respectively. Thirdly, the below detection limit results for some of the metal ions and the very low concentrations of those detected are pointers to the absence of industrial activities and mining. Finally, the groundwater in the study area is considered to be generally safe with respect to the contaminants studied and results posted for the composite samples. Inhabitants are therefore under no illusion of immediate or remote health challenges with regards to the heavy metals analyzed. More individual sampling, however, is recommended. PMID:25853026

  3. The ColRS signal transduction system responds to the excess of external zinc, iron, manganese, and cadmium

    PubMed Central

    2014-01-01

    Background The ColRS two-component system has been shown to contribute to the membrane functionality and stress tolerance of Pseudomonas putida as well as to the virulence of Pseudomonas aeruginosa and plant pathogenic Xanthomonas species. However, the conditions activating the ColRS pathway and the signal(s) sensed by ColS have remained unknown. Here we aimed to analyze the role of the ColRS system in metal tolerance of P. putida and to test whether ColS can respond to metal excess. Results We show that the ColRS system is necessary for P. putida to tolerate the excess of iron and zinc, and that it also contributes to manganese and cadmium tolerance. Excess of iron, zinc, manganese or cadmium activates ColRS signaling and as a result modifies the expression of ColR-regulated genes. Our data suggest that the genes in the ColR regulon are functionally redundant, as several loci have to be deleted to observe a significant decrease in metal tolerance. Site-directed mutagenesis of ColS revealed that excess of iron and, surprisingly, also zinc are sensed by a conserved ExxE motif in ColS’s periplasmic domain. While ColS is able to sense different metals, it still discriminates between the two oxidation states of iron, specifically responding to ferric and not ferrous iron. We propose a signal perception model involving a dimeric ColS, where each monomer donates one ExxE motif for metal binding. Conclusions Several transition metals are essential for living organisms in certain amounts, but toxic in excess. We show that ColRS is a sensor system which detects and responds to the excess of physiologically important metals such as zinc, iron and manganese. Thus, the ColRS system is an important factor for metal homeostasis and tolerance in P. putida. PMID:24946800

  4. Inductively coupled plasma atomic fluorescence spectrometric determination of cadmium, copper, iron, lead, manganese and zinc

    USGS Publications Warehouse

    Sanzolone, R.F.

    1986-01-01

    An inductively coupled plasma atomic fluorescence spectrometric method is described for the determination of six elements in a variety of geological materials. Sixteen reference materials are analysed by this technique to demonstrate its use in geochemical exploration. Samples are decomposed with nitric, hydrofluoric and hydrochloric acids, and the residue dissolved in hydrochloric acid and diluted to volume. The elements are determined in two groups based on compatibility of instrument operating conditions and consideration of crustal abundance levels. Cadmium, Cu, Pb and Zn are determined as a group in the 50-ml sample solution under one set of instrument conditions with the use of scatter correction. Limitations of the scatter correction technique used with the fluorescence instrument are discussed. Iron and Mn are determined together using another set of instrumental conditions on a 1-50 dilution of the sample solution without the use of scatter correction. The ranges of concentration (??g g-1) of these elements in the sample that can be determined are: Cd, 0.3-500; Cu, 0.4-500; Fe, 85-250 000; Mn, 45-100 000; Pb, 5-10 000; and Zn, 0.4-300. The precision of the method is usually less than 5% relative standard deviation (RSD) over a wide concentration range and acceptable accuracy is shown by the agreement between values obtained and those recommended for the reference materials.

  5. Drinking Water Problems: Iron and Manganese 

    E-print Network

    Dozier, Monty; McFarland, Mark L.

    2004-02-20

    Iron and manganese can give water an unpleasant taste, odor and color. In this publication you'll learn how to know whether your water contains iron or manganese and how to eliminate these contaminants with various treatment methods such as aeration...

  6. Tetragonal and Hexagonal Iron-Manganese Carbides

    Microsoft Academic Search

    M. J. Duggin

    1967-01-01

    DURING recent studies of the iron-manganese-carbon system, specimens, each weighing approximately 5 g, were carefully prepared according to predetermined compositions. The components were 500-mesh powders of 99.995 per cent pure iron and spectroscopically pure carbon and a 200-mesh powder of 99.995 per cent pure manganese. The component powders were intimately mixed by shaking, then each specimen was packed into a

  7. Iron-manganese nanowires for magnetoresistance

    NASA Astrophysics Data System (ADS)

    Brown, Joshua M.; Wilson, Chester

    2010-04-01

    The research presented in this abstract pertains to nanowire-structured magnetic sensors fabricated by pulsed, template electrodeposition relying on giant magnetoresistance (GMR). System fabrication involves electrodepositing metals with a DC-biased square wave from a solution of iron-manganese solution into the porous aluminum oxide surface of an aluminum sheet. The chemical make-up of the resulting 20nm diameter, 500nm length nanowires was 6 at% manganese and 45 at% iron, which is desirable because the ferromagnetic layers (Fe) should be large in comparison with the nonmagnetic layers (Mn). The resulting nanowires exhibited a 73% drop in resistance when exposed to an external magnetic field.

  8. A zinc-resistant human epithelial cell line is impaired in cadmium and manganese import

    SciTech Connect

    Rousselet, Estelle [CEA, DSV, IRTSV, Laboratoire de Chimie et Biologie des Metaux, Grenoble (France)]|[LCBM, CNRS UMR5249, Grenoble (France); Universite Joseph Fourier, Grenoble (France); Richaud, Pierre [CEA, DSV, IBEB, SBVME, LB3M, Saint-Paul-lez-Durance (France)]|[LB3M, CNRS UMR 6191, Saint-Paul-lez-Durance (France)]|[Universite Aix-Marseille (France); Douki, Thierry; Chantegrel, Jocelyne Garcia; Favier, Alain [Universite Joseph Fourier, Grenoble (France)]|[CEA, DSM, INaC/SCIB, Laboratoire 'Lesions des Acides Nucleiques', Grenoble (France); Bouron, Alexandre [CEA, DSV, IRTSV, Laboratoire de Chimie et Biologie des Metaux, Grenoble (France)]|[LCBM, CNRS UMR5249, Grenoble (France)]|[Universite Joseph Fourier, Grenoble (France); Moulis, Jean-Marc [CEA, DSV, IRTSV, Laboratoire de Chimie et Biologie des Metaux, Grenoble (France)]|[LCBM, CNRS UMR5249, Grenoble (France)]|[Universite Joseph Fourier, Grenoble (France)], E-mail: jean-marc.moulis@cea.fr

    2008-08-01

    A human epithelial cell line (HZR) growing with high zinc concentrations has been analyzed for its ability to sustain high cadmium concentrations. Exposure to up to 200 {mu}M of cadmium acetate for 24 h hardly impacted viability, whereas most of parental HeLa cells were killed by less than 10 {mu}M of cadmium. Upon challenge by 35 fold higher cadmium concentrations than HeLa cells, HZR cells did not display increased DNA damage, increased protein oxidation, or changed intracellular cadmium localization. Rather, the main cause of resistance against cadmium was by avoiding cadmium entry into cells, which differs from that against zinc as the latter accumulates inside cells. The zinc-resistant phenotype of these cells was shown to also impair extracellular manganese uptake. Manganese and cadmium competed for entry into HeLa cells. Probing formerly identified cadmium or manganese transport systems in different animal cells did not evidence any significant change between HeLa and HZR cells. These results reveal zinc adaptation influences manganese and cadmium cellular traffic and they highlight previously unknown connections among homeostasis of divalent metals.

  9. Simultaneous determination of arsenic, cadmium, calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, molybdenum, nickel, selenium, and zinc in fertilizers by microwave acid digestion and inductively coupled plasma-optical emission spectrometry detection: single-laboratory validation of a modification and extension of AOAC 2006.03.

    PubMed

    Webb, Sharon; Bartos, James; Boles, Rhonda; Hasty, Elaine; Thuotte, Ethel; Thiex, Nancy J

    2014-01-01

    A single-laboratory validation study was conducted for the simultaneous determination of arsenic, cadmium, calcium, cobalt, copper, chromium, iron, lead, magnesium, manganese, molybdenum, nickel, selenium, and zinc in all major types of commercial fertilizer products by microwave digestion and inductively coupled plasma-optical emission spectroscopy analysis. This validation study proposes an extension and modification of AOAC 2006.03. The extension is the inclusion of calcium, copper, iron, magnesium, manganese, and zinc, and the modification is incorporation of hydrochloric acid in the digestion system. This dual acid digestion utilizes both hydrochloric and nitric acids in a 3 to 9 mL volume ratio/100 mL. In addition to 15 of the 30 original validation materials used in the 2006.03 collaborative study, National Institute of Standards and Technology Standard Reference Material 695 and Magruder 2009-06 were incorporated as accuracy materials. The main benefits of this proposed method are a significant increase in laboratory efficiency when compared to the use of both AOAC Methods 965.09 and 2006.03 to achieve the same objective and an enhanced recovery of several metals. PMID:25051614

  10. Iron and manganese removal by using manganese ore constructed wetlands in the reclamation of steel wastewater.

    PubMed

    Xu, Jing-Cheng; Chen, Gu; Huang, Xiang-Feng; Li, Guang-Ming; Liu, Jia; Yang, Na; Gao, Sai-Nan

    2009-09-30

    To reclaim treated steel wastewater as cooling water, manganese ore constructed wetland was proposed in this study for the removal of iron and manganese. In lab-scale wetlands, the performance of manganese ore wetland was found to be more stable and excellent than that of conventional gravel constructed wetland. The iron and manganese concentration in the former was below 0.05 mg/L at hydraulic retention time of 2-5 days when their influent concentrations were in the range of 0.16-2.24 mg/L and 0.11-2.23 mg/L, respectively. Moreover, its removals for COD, turbidity, ammonia nitrogen and total phosphorus were 55%, 90%, 67% and 93%, respectively, superior to the corresponding removals in the gravel wetland (31%, 86%, 58% and 78%, respectively). The good performance of manganese ore was ascribed to the enhanced biological manganese removal with the aid of manganese oxide surface and the smaller size of the medium. The presence of biological manganese oxidation was proven by the facts of good manganese removal in wetlands at chemical unfavorable conditions (such as ORP and pH) and the isolation of manganese oxidizing strains from the wetlands. Similar iron and manganese removal was later observed in a pilot-scale gravel-manganese-ore constructed wetland, even though the manganese ore portion in total volume was reduced from 100% (in the lab-scale) to only 4% (in the pilot-scale) for the sake of cost-saving. The quality of the polished wastewater not only satisfied the requirement for cooling water but also suitable as make-up water for other purposes. PMID:19443107

  11. The content of manganese and iron in hip joint tissue.

    PubMed

    Brodziak-Dopiera?a, Barbara; Kwapuli?ski, Jerzy; Sobczyk, Krzysztof; Wiechu?a, Danuta

    2013-07-01

    Manganese and iron are elements that constitute components of bone tissue. The aim of this study was to determine presence of manganese and iron in hip joint tissue and interdependencies between these elements. The objects of the research were hip joint elements from people residing in cities on the territory of the Upper Silesian Industrial District. The number of people in the study group was 91 samples, including 66 samples from women and 25 from a man. The examined tissues were obtained intraoperatively during hip replacement procedures. The content of manganese and iron was determined using the atomic absorption spectrophotometry (AAS) method. The lowest content of manganese and iron was found in the cortical bone, and the largest, in the case of manganese, in the articular cartilage, whereas in the case of iron in a fragment of the cancellous bone from the intertrochanteric area. The content of iron in selected elements of the hip joint decreased with age. Higher content of manganese in hip joint tissue of women compared to men was confirmed. What is more, higher content of iron in hip joint tissue of men was confirmed as well. PMID:23415599

  12. Manganese, Iron, and sulfur cycling in Louisiana continental shelf sediments

    EPA Science Inventory

    Sulfate reduction is considered the primary pathway for organic carbon remineralization on the northern Gulf of Mexico Louisiana continental shelf (LCS) where bottom waters are seasonally hypoxic, yet limited information is available on the importance of iron and manganese cyclin...

  13. Oxygen toxicity in Streptococcus mutans: manganese, iron and superoxide dismutase

    SciTech Connect

    Martin, M.E.; Strachan, R.C.; Aranha, H.; Evans, S.L.; Salin, M.L.; Welch, B.; Arceneaux, J.E.L.; Byers, B.R.

    1984-07-01

    When cultured anaerobically in a chemically defined medium that was treated with Chelex-100 to lower its trace metal content, Streptococcus mutans OMZ176 had no apparent requirement for manganese or iron. Manganese or iron was necessary for aerobic cultivation in deep static cultures. During continuous aerobic cultivation in a stirred chemostat, iron did not support the growth rate achieved with manganese. Since the dissolved oxygen level in the chemostat cultures was higher than the final level in the static cultures, manganese may be required for growth at elevated levels. In medium supplemented with manganese, cells grown anaerobically contained a low level of superoxide dismutase (SOD) activity; aerobic cultivation increased SOD activity at least threefold. In iron-supplemented medium, cells grown anaerobically also had low SOD activity; aerobic incubation resulted in little increase in SOD activity. Polyacrylamide gel electrophoresis of the cell extracts revealed a major band and a minor band of SOD activity in the cells grown with manganese; however, cells grown with iron contained a single band of SOD activity with an R/sub f/ value similar to that of the major band found in cells grown with manganese. None of the SOD activity bands were abolished by the inclusion of 2 mM hydrogen peroxide in the SOD activity strain. S. mutans may not produce a separate iron-containing SOD but may insert either iron or manganese into an apo-SOD protein. Alternatively, iron may function in another activity (not SOD) that augments the defense against oxygen toxicity at low SOD levels. 28 references, 3 figures, 1 table.

  14. Cadmium and manganese flux in eelgrass Zostera marina II. Metal uptake by leaf and root-rhizome tissues

    Microsoft Academic Search

    B. H. Brinkhuis; W. F. Penello; A. C. Churchill

    1980-01-01

    Cadmium and manganese radionuclide uptake by Zostera marina L. tissues and translocation between rootrhizomes and leaves was examined. Cadmium concentrations in root-rhizomes increased with incubation time but appeared to reach saturation levels at 24 h of exposure. Translocation of cadmium between root-rhizomes and leaves occurred in both directions. A greater flux of cadmium downward suggested that root-rhizomes were a cadmium

  15. Effects of high but nontoxic dietary manganese and iron on their metabolism by calves

    SciTech Connect

    Ho, S.Y.; Miller, W.J.; Gentry, R.P.; Neathery, M.W.; Blackmon, D.M.

    1984-07-01

    Sixteen male Holstein calves were fed one of four diets for 18 days in an experiment consisting of 0 and 1000 ppm supplemental manganese and 0 and 1000 ppm added iron as manganese carbonate and ferrous carbonate. The control diet contained 55 ppm manganese and 220 ppm iron. All calves were dosed orally 48 h prior to sacrifice with 500 ..mu..Ci of manganese-54. Small intestinal iron was less in calves fed a high manganese diet, a possible interaction of these two elements at the absorption site. Feeding a high manganese diet tended to decrease iron (total) concentrations in liver and pancreas. When the high manganese diet was supplemented with additional iron, antagonistic effects of manganese on iron were eliminated. Neither iron nor manganese concentrations in tissues were affected by an increase of dietary iron. Manganese-54 content of tissue was reduced by the high manganese diet but was not affected by dietary iron. Total manganese and iron in feces fairly closely reflected dietary intake of each element with no evidence of interaction. Calves fed the high iron diet excreted less manganese-54 in their feces over 2 days. Total iron in blood serum was not affected significantly by the dietary treatments. 22 references, 2 figures, 7 tables.

  16. Effects of high but nontoxic dietary manganese and iron on their metabolism by calves.

    PubMed

    Ho, S Y; Miller, W J; Gentry, R P; Neathery, M W; Blackmon, D M

    1984-07-01

    Sixteen male Holstein calves were fed one of four diets for 18 days in an experiment consisting of 0 and 1000 ppm supplemental manganese and 0 and 1000 ppm added iron as manganese carbonate and ferrous carbonate. The control diet contained 55 ppm manganese and 220 ppm iron. All calves were dosed orally 48 h prior to sacrifice with 500 muCi of manganese-54. Small intestinal iron was less in calves fed a high manganese diet, a possible interaction of these two elements at the absorption site. Feeding a high manganese diet tended to decrease iron (total) concentrations in liver and pancreas. When the high manganese diet was supplemented with additional iron, antagonistic effects of manganese on iron were eliminated. Neither iron nor manganese concentrations in tissues were affected by an increase of dietary iron. Manganese-54 content of tissue was reduced by the high manganese diet but was not affected by dietary iron. Total manganese and iron in feces fairly closely reflected dietary intake of each element with no evidence of interaction. Calves fed the high iron diet excreted less manganese-54 in their feces over 2 days. Total iron in blood serum was not affected significantly by the dietary treatments. PMID:6747050

  17. Lake destratification and speciation of iron and manganese.

    PubMed

    Chiswell, B; Zaw, M

    1991-10-01

    A long-term study of the effect of artificial aeration (destratification) of a water storage dam upon the speciation of iron and manganese in the dam waters has been undertaken. Separation of dam samples into soluble and insoluble forms by selective membrane filtration was undertaken before using the techniques of EPR spectroscopy, ion chromatography and gel filtration to assess the speciation of soluble species, and selective extraction and surface analysis (ESCA, SIMS and SEM) techniques to determine the speciation of particulate iron and manganese species. The percentages of soluble iron and manganese before (1983-85) and after (1986-88) artificial aeration are compared for the periods Jan-Dec, Jan-Mar, and Jun-Aug at three depths 6 m, 15 m and 0.5 m above the dam base, to assess the importance of seasonal changes in the various depths of the dam. Although aeration had an initial marked reduction in levels of soluble iron and manganese at all depths of the dam, the concentrations of these mtals showed a steady increase over succeeding years. Analysis of the figures over summer and winter periods shows that the reduction of soluble iron was maintained in summer, but not during winter. Upon aeration, the initial reduction of soluble manganese concentration was maintained in succeeding years in the epilimnic regions of the dam, but not in the hypolimnion. Statistical analysis of data has been undertaken to correlate the changes in relationship between the various forms of iron and manganese with the advent of aeration. PMID:24233959

  18. Long-Term Follow-Up of Workplace and Well Water Manganese Effects on Iron Status Indexes in Manganese Miners

    Microsoft Academic Search

    Massod Mashhadi; Akbar Boojar; Faranak Goodarzi; Mohamad Ali Basedaghat

    2002-01-01

    The authors assessed the effect of water reconstitution in the workplace by evaluating the iron status of manganese mine workers during a long-term study. Subsequent analyses and biological monitoring were performed in a group of 150 manganese miners before, and 2.8 yr after, reconstitution of drinking water in the miners' workplace. The authors found significantly high concentrations of manganese in

  19. Levels of cadmium, manganese and lead in water and algae; Spirogyra aequinoctialis

    Microsoft Academic Search

    C. C. Kaonga; S. S. Chiotha; E. Fabiano; E. M. Henry

    This study assessed the ability of filamentous green algae; Spirogyra aequinoctialis to accumulate manganese, cadmium and lead from water. Water pH was also determined. Samples of S. aequinoctialis and their respective water environments were taken from designated sampling points in the city of Blantyre and Malawi during the rainy and dry season in order to capture seasonal variations. The concentration

  20. Elements of the iron and manganese cycles in Lake Baikal

    USGS Publications Warehouse

    Granina, L.Z.; Callender, E.

    2007-01-01

    Using data obtained in recent years, we considered the external mass balance and characteristics of internal iron and manganese cycles in Lake Baikal (biological uptake, remineralization, sedimentary and diffusive fluxes, accumulation in sediments, time of renewal, etc.). Some previous results and common concepts were critically reevaluated. ?? Pleiades Publishing, Ltd. 2007.

  1. Effects of high but nontoxic dietary manganese and iron on their metabolism by calves

    Microsoft Academic Search

    S. Y. Ho; W. J. Miller; R. P. Gentry; M. W. Neathery; D. M. Blackmon

    1984-01-01

    Sixteen male Holstein calves were fed one of four diets for 18 days in an experiment consisting of 0 and 1000 ppm supplemental manganese and 0 and 1000 ppm added iron as manganese carbonate and ferrous carbonate. The control diet contained 55 ppm manganese and 220 ppm iron. All calves were dosed orally 48 h prior to sacrifice with 500

  2. Adsorption of selenium by amorphous iron oxyhydroxide and manganese dioxide

    USGS Publications Warehouse

    Balistrieri, L.S.; Chao, T.T.

    1990-01-01

    This work compares and models the adsorption of selenium and other anions on a neutral to alkaline surface (amorphous iron oxyhydroxide) and an acidic surface (manganese dioxide). Selenium adsorption on these oxides is examined as a function of pH, particle concentration, oxidation state, and competing anion concentration in order to assess how these factors might influence the mobility of selenium in the environment. The data indicate that 1. 1) amorphous iron oxyhydroxide has a greater affinity for selenium than manganese dioxide, 2. 2) selenite [Se(IV)] adsorption increases with decreasing pH and increasing particle concentration and is stronger than selenate [Se(VI)] adsorption on both oxides, and 3. 3) selenate does not adsorb on manganese dioxide. The relative affinity of selenate and selenite for the oxides and the lack of adsorption of selenate on a strongly acidic surface suggests that selenate forms outer-sphere complexes while selenite forms inner-sphere complexes with the surfaces. The data also indicate that the competition sequence of other anions with respect to selenite adsorption at pH 7.0 is phosphate > silicate > molybdate > fluoride > sulfate on amorphous iron oxyhydroxide and molybdate ??? phosphate > silicate > fluoride > sulfate on manganese dioxide. The adsorption of phosphate, molybdate, and silicate on these oxides as a function of pH indicates that the competition sequences reflect the relative affinities of these anions for the surfaces. The Triple Layer surface complexation model is used to provide a quantitative description of these observations and to assess the importance of surface site heterogeneity on anion adsorption. The modeling results suggest that selenite forms binuclear, innersphere complexes with amorphous iron oxyhydroxide and monodentate, inner-sphere complexes with manganese dioxide and that selenate forms outer-sphere, monodentate complexes with amorphous iron oxyhydroxide. The heterogeneity of the oxide surface sites is reflected in decreasing equilibrium constants for selenite with increasing adsorption density and both experimental observations and modeling results suggest that manganese dioxide has fewer sites of higher energy for selenite adsorption than amorphous iron oxyhydroxide. Modeling and interpreting the adsorption of phosphate, molybdate, and silicate on the oxides are made difficult by the lack of constraint in choosing surface species and the fact that equally good fits can be obtained with different surface species. Finally, predictions of anion competition using the model results from single adsorbate systems are not very successful because the model does not account for surface site heterogeneity. Selenite adsorption data from a multi-adsorbate system could be fit if the equilibrium constant for selenite is decreased with increasing anion adsorption density. ?? 1990.

  3. The manganese and iron superoxide dismutases protect Escherichia coli from heavy metal toxicity.

    PubMed

    Geslin, C; Llanos, J; Prieur, D; Jeanthon, C

    2001-12-01

    Superoxide dismutases (SODs) are vital components that defend against oxidative stress through decomposition of superoxide radical. Escherichia coli contains two highly homologous SODs, a manganese- and an iron-containing enzyme (Mn-SOD and Fe-SOD, respectively). In contrast, a single Mn-SOD is present in Bacillus subtilis. In E. coli, the absence of SODs was found to be associated with an increased sensitivity to cadmium, nickel and cobalt ions. Mutants lacking either sodA or sodB exhibited metal resistance to levels comparable to that of the wild-type strain. Although sod-deficient mutant cells were more resistant to zinc than their wild-type counterpart, no differences between the strains were observed in the presence of copper. In B. subtilis, the sodA mutation had no effect on cadmium and copper resistance. These results suggest that intracellular generation of superoxide by cadmium, nickel and cobalt is toxic in E. coli. They support the participation of sod genes in its protection against metal stress. PMID:11766965

  4. Effects of iron and manganese on the formation of HAAs upon chlorinating Chlorella vulgaris

    Microsoft Academic Search

    Fei Ge; Xiuzhen Wu; Na Wang; Runliang Zhu; Tong Wang; Yin Xu

    2011-01-01

    The major objective of the present study was to investigate the role of iron and manganese on the formation of haloacetic acids (HAAs) when algae are chlorinated at different pHs. The results showed that both iron and manganese can reduce the yields of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) on chlorinating green alga Chlorella vulgaris (C. vulgaris) at a

  5. THE ACCUMULATION AND DISTRIBUTION OF VANADIUM, IRON, AND MANGANESE IN SOME SOLITARY ASCIDIANS

    Microsoft Academic Search

    H. MICHIBATA; T. TERADA; N. ANADA; K. YAMAKAWA; T. NUMAKUNAI

    The vanadium, iron, and manganese contents of 15 species of solitary ascidians belonging to the suborders Phlebobranchia and Stolidobranchia were determined by thermal neutron activation analysis. Vanadium was detectable in all species exam med. In general, the vanadium content in various tissues ofthe Phlebobranchia was considerably higher than the iron and manganese contents. The blood cells especially contained a large

  6. Manganese Doping of Magnetic Iron Oxide Nanoparticles: Tailoring Surface Reactivity for a Regenerable Heavy Metal Sorbent

    SciTech Connect

    Warner, Cynthia L.; Chouyyok, Wilaiwan; Mackie, Katherine E.; Neiner, Doinita; Saraf, Laxmikant; Droubay, Timothy C.; Warner, Marvin G.; Addleman, Raymond S.

    2012-02-28

    A method for tuning the analyte affinity of magnetic, inorganic nanostructured sorbents for heavy metal contaminants is described. The manganese-doped iron oxide nanoparticle sorbents have a remarkably high affinity compared to the precursor material. Sorbent affinity can be tuned toward an analyte of interest simply by adjustment of the dopant quantity. The results show that following the Mn doping process there is a large increase in affinity and capacity for heavy metals (i.e., Co, Ni, Zn, As, Ag, Cd, Hg, and Tl). Capacity measurements were carried out for the removal of cadmium from river water and showed significantly higher loading than the relevant commercial sorbents tested for comparison. The reduction in Cd concentration from 100 ppb spiked river water to 1 ppb (less than the EPA drinking water limit of 5 ppb for Cd) was achieved following treatment with the Mn-doped iron oxide nanoparticles. The Mn-doped iron oxide nanoparticles were able to load 1 ppm of Cd followed by complete stripping and recovery of the Cd with a mild acid wash. The Cd loading and stripping is shown to be consistent through multiple cycles with no loss of sorbent performance.

  7. Distributions of Manganese, Iron, and Manganese-Oxidizing Bacteria In Lake Superior Sediments of Different Organic Carbon Content

    NASA Technical Reports Server (NTRS)

    Richardson, Laurie L.; Nealson, Kenneth H.

    1989-01-01

    Profiles of oxygen, soluble and particulate manganese and iron, organic carbon and nitrogen were examined in Lake Superior sediment cores, along with the distribution and abundance of heterotrophic and manganese oxidizing bacteria. Analyses were performed using cores collected with the submersible Johnson Sea Link II. Three cores, exhibiting a range of organic carbon content, were collected from the deepest basin in Lake Superior and the north and south ends of the Caribou trough, and brought to the surface for immediate analysis. Minielectrode profiles of oxygen concentration of the three cores were carried out using a commercially available minielectrode apparatus. Oxygen depletion to less than 1% occurred within 4 cm of the surface for two of the cores, but not until approximately 15 cm for the core from the south basin of the Caribou trough. The three cores exhibited very different profiles of soluble, as well as leachable, manganese and iron, suggesting different degrees of remobilization of these metals in the sediments. Vertical profiles of viable bacteria and Mn oxidizing bacteria, determined by plating and counting, showed that aerobic (and facultatively aerobic) heterotrophic bacteria were present at the highest concentrations near the surface and decreased steadily with depth, while Mn oxidizing bacteria were concentrations primarily at and above the oxic/anoxic interface. Soluble manganese in the pore waters, along with abundant organic carbon, appeared to enhance the presence of manganese oxidizing bacteria, even below the oxic/anoxic interface. Profiles of solid-phase leachable manganese suggested a microbial role in manganese reprecipitation in these sediments.

  8. Blood Metal Concentrations of Manganese, Lead, and Cadmium in Relation to Serum Ferritin Levels in Ohio Residents

    EPA Science Inventory

    The objectives of this study were to assess fcrritin-specific profiles of blood metal concentrations such as manganese, lead, and cadmium and to evaluate whether ferritin may affect the behavior of the blood metals in relation to menstruation, menopause, or sex in Ohio residents....

  9. Potentiating effects of oxygen in lungs damaged by methylcyclopentadienyl manganese tricarbonyl, cadmium chloride, oleic acid, and antitumor drugs

    Microsoft Academic Search

    P. J. Hakkinen; C. C. Morse; F. M. Martin; W. E. Dalbey; W. M. Haschek; H. R. Witschi

    1983-01-01

    The intraperitoneal administration of methylcyclopentadienyl manganese tricarbonyl (MMT) and cyclophosphamide, exposure to an aerosol of cadmium chloride, intravenous administration of oleic acid, and intratracheal instillation of bleomycin to young female BALB\\/c mice or CD\\/CR rats result in acute lung injury. Pulmonary morphology and lung collagen content were examined in animals treated with these chemicals alone or in combination with an

  10. Self-focusing of laser beams in cadmium manganese telluride Cd(0.4)Mn(0.6)Te

    Microsoft Academic Search

    X. D. Dai; Y. Ito; Y. H. Ja

    1990-01-01

    Laser beam induced self-focusing in a relatively new diluted magnetic semiconductor cadmium manganese telluride, Cd(0.4)Mn(0.6)Te has been observed. It is found that a thermally-induced change in nonlinear refractive index is the main mechanism responsible for the self-focusing effect. The nonlinear refractive index has been determined using experimental results.

  11. Trivalent chromium, manganese, iron and cobalt chelates of a tetradentate N 6 macrocyclie ligand

    Microsoft Academic Search

    Vidya B. Rana; Prabha Singh; Dharam P. Singh; Mahendra P. Teotia

    1982-01-01

    Summary Trivalent chromium, manganese, iron and cobalt salts reactin situ with 2,6-diaminopyridine and acetylacetone to form complexes of the 16-membered N6 tetradentate macrocyclic ligand. The chelates are characterised as distorted square-pyramidal of [M(TML)X] type, where M = chromium(III), manganese(III), iron(III) and cobalt(III); X=Cl, Br, NO3 or NCS for chromium(III) and iron(III) and X=(OAc) for manganese(III) and (OH) for cobalt(III). The

  12. Evolution of Microstructures During Austempering of Ductile Irons Alloyed with Manganese and Copper

    NASA Astrophysics Data System (ADS)

    Dasgupta, Ranjan Kumar; Mondal, Dipak Kumar; Chakrabarti, Ajit Kumar

    2013-03-01

    The influences of relatively high manganese (0.45 through 1.0 wt pct) and copper (0.56 through 1.13 wt pct) contents on microstructure development and phase transformation in three austempered ductile irons have been studied. The experimental ductile irons alloyed with copper and manganese are found to be practically free from intercellular manganese segregation. This suggests that the positive segregation of manganese is largely neutralized by the negative segregation of copper when these alloying elements are added in appropriate proportions. The drop in unreacted austenite volume (UAV) with increasing austempering temperature and time is quite significant in irons alloyed with copper and manganese. The ausferrite morphology also undergoes a transition from lenticular to feathery appearance of increasing coarseness with the increasing austempering temperature and time. SEM micrographs of the austempered samples from the base alloy containing manganese only, as well as copper plus manganese-alloyed irons, clearly reveal the presence of some martensite along with retained austenite and ferrite. X-ray diffraction analysis also confirms the presence of these phases. SEM examination further reveals the presence of twinned martensite in the copper plus manganese-alloyed samples. The possibility of strain-induced transformation of austenite to martensite during austempering heat treatment is suggested.

  13. Influences on the oceanic biogeochemical cycling of the hybrid-type metals, cobalt, iron, and manganese

    E-print Network

    Noble, Abigail Emery

    2012-01-01

    Trace metal cycling is one of many processes that influence ocean ecosystem dynamics. Cobalt, iron, and manganese are redox active trace metal micro-nutrients with oceanic distributions that are influenced by both biological ...

  14. Role of manganese in protection against oxidative stress under iron starvation in cyanobacterium Anabaena 7120.

    PubMed

    Kaushik, Manish Singh; Srivastava, Meenakshi; Verma, Ekta; Mishra, Arun Kumar

    2015-06-01

    The cyanobacterium Anabaena sp. PCC 7120 was grown in presence and absence of iron to decipher the role of manganese in protection against the oxidative stress under iron starvation and growth, manganese uptake kinetics, antioxidative enzymes, lipid peroxidation, electrolyte leakage, thiol content, total peroxide, proline and NADH content was investigated. Manganese supported the growth of cyanobacterium Anabaena 7120 under iron deprived conditions where maximum uptake rate of manganese was observed with lower Km and higher Vmax values. Antioxidative enzymes were also found to be elevated in iron-starved conditions. Estimation of lipid peroxidation and electrolyte leakage depicted the role of manganese in stabilizing the integrity of the membrane which was considered as the prime target of oxygen free radicals in oxidative stress. The levels of total peroxide, thiol, proline and NADH content, which are the representative of oxidative stress response in Anabaena 7120, were also showed increasing trends in iron starvation. Hence, the results discerned, clearly suggested the role of manganese in protection against the oxidative stress in cyanobacterium Anabaena 7120 under iron starvation either due to its antioxidative properties or involvement as cofactor in a number of antioxidative enzymes. PMID:25572501

  15. An optically-interrogated microwave-Poynting-vector sensor using cadmium manganese telluride.

    PubMed

    Chen, Chia-Chu; Whitaker, John F

    2010-06-01

    A single <110> cadmium-manganese-telluride crystal that exhibits both the Pockels and Faraday effects is used to produce a Poynting-vector sensor for signals in the microwave regime. This multi-birefringent crystal can independently measure either electric or magnetic fields through control of the polarization of the optical probe beam. After obtaining all the relevant electric and magnetic field components, a map of the Poynting vector along a 50-Omega microstrip was experimentally determined without the need for any further transformational calculations. The results demonstrate that this sensor can be used for near-field mapping of the Poynting vector. Utilizing both amplitude and phase information from the fields in the microwave signal, it was confirmed for the case of an open-terminated microstrip that no energy flowed to the load, while for a microstrip with a matched termination, the energy flowed consistently along the transmission line. PMID:20588348

  16. Concentration of Lead, Mercury, Cadmium, Aluminum, Arsenic and Manganese in Umbilical Cord Blood of Jamaican Newborns

    PubMed Central

    Rahbar, Mohammad H.; Samms-Vaughan, Maureen; Dickerson, Aisha S.; Hessabi, Manouchehr; Bressler, Jan; Coore Desai, Charlene; Shakespeare-Pellington, Sydonnie; Reece, Jody-Ann; Morgan, Renee; Loveland, Katherine A.; Grove, Megan L.; Boerwinkle, Eric

    2015-01-01

    The objective of this study was to characterize the concentrations of lead, mercury, cadmium, aluminum, and manganese in umbilical cord blood of Jamaican newborns and to explore the possible association between concentrations of these elements and certain birth outcomes. Based on data from 100 pregnant mothers and their 100 newborns who were enrolled from Jamaica in 2011, the arithmetic mean (standard deviation) concentrations of cord blood lead, mercury, aluminum, and manganese were 0.8 (1.3 ?g/dL), 4.4 (2.4 ?g/L), 10.9 (9.2 ?g/L), and 43.7 (17.7 ?g/L), respectively. In univariable General Linear Models, the geometric mean cord blood aluminum concentration was higher for children whose mothers had completed their education up to high school compared to those whose mothers had any education beyond high school (12.2 ?g/L vs. 6.4 ?g/L; p < 0.01). After controlling for maternal education level and socio-economic status (through ownership of a family car), the cord blood lead concentration was significantly associated with head circumference (adjusted p < 0.01). Our results not only provide levels of arsenic and the aforementioned metals in cord blood that could serve as a reference for the Jamaican population, but also replicate previously reported significant associations between cord blood lead concentrations and head circumference at birth in other populations. PMID:25915835

  17. Iron deficiency increases blood concentrations of neurotoxic metals in children

    PubMed Central

    Kim, Yangho

    2014-01-01

    Iron deficiency affects approximately one-third of the world's population, occurring most frequently in children aged 6 months to 3 years. Mechanisms of iron absorption are similar to those of other divalent metals, particularly manganese, lead, and cadmium, and a diet deficient in iron can lead to excess absorption of manganese, lead, and cadmium. Iron deficiency may lead to cognitive impairments resulting from the deficiency itself or from increased metal concentrations caused by the deficiency. Iron deficiency combined with increased manganese or lead concentrations may further affect neurodevelopment. We recently showed that blood manganese and lead concentrations are elevated among iron-deficient infants. Increased blood manganese and lead levels are likely associated with prolonged breast-feeding, which is also a risk factor for iron deficiency. Thus, babies who are breast-fed for prolonged periods should be given plain, iron-fortified cereals or other good sources of dietary iron. PMID:25210521

  18. Manganese-mitigation of cadmium toxicity to seedling growth of Phytolacca acinosa Roxb. is controlled by the manganese/cadmium molar ratio under hydroponic conditions.

    PubMed

    Liu, Huimin; Zhang, Yuxiu; Chai, Tuanyao; Tan, Jinjuan; Wang, Jianwu; Feng, Shanshan; Liu, Geyu

    2013-12-01

    Manganese (Mn) can interact with cadmium (Cd) in environments and influence the toxic effect of Cd on plants. However, few studies have investigated the relationship between the Mn/Cd ratio and plant Cd-toxicity along Cd concentrations. In this paper, we studied the effects of external Mn/Cd molar ratios (0, 10, 30, 50 and 60) on Cd toxicity in the Mn hyperaccumulator and Cd tolerant plant, Phytolacca acinosa Roxb., at three Cd levels (50, 100 and 200 ?M) under hydroponic conditions. Our result showed that seedling growth (y) under Cd stress was strongly positively related to the solution Mn/Cd molar ratio (SMCR). The relationship between the two variables under solution Cd concentrations was well explained by the linear regression model y=a+b1 (SMCR)+b2 (Solution-Cd). Increasing SMCR significantly reduced the Cd concentration and increased the Mn concentration in plant tissues. However, seedling growth was consistent with the shoot Mn/Cd molar ratio rather than with the Mn or Cd concentrations in plant tissues. At low levels of SMCR (e.g. 0 and 10), elevation of Mn distribution in shoot tissues might be a mechanism in P. acinosa seedlings to defend against Cd-toxicity. In comparison with low levels of SMCR, high levels of SMCR (e.g. 50 and 60) greatly alleviated lipid peroxidation and plant water-loss, and enhanced photosynthesis. However, the alleviated lipid peroxidation in the Mn-mitigation of Cd toxicity was likely to be the secondary effect resulting from the antagonism between Mn and Cd in the plant. PMID:24095921

  19. Iron, Manganese and Copper Release from Synthetic Hydroxyapatite

    NASA Technical Reports Server (NTRS)

    Sutter, B.; Hossner, L. R.; Ming, Douglas W.

    1999-01-01

    Kinetic stir-flow dissolution experiments were performed on iron- (Fe-SHA), manganese- (Mn-SHA), and copper- (Cu-SHA) containing synthetic hydroxyapatites. Solution treatments consisted of de-ionized water, citric acid and DTPA. Initially, Mn concentrations were higher than Cu concentrations and Fe concentrations were the lowest in all treatments. At later times Mn and Cu concentrations dropped in the DTPA treatment while Fe rose to the concentration similar to Mn and Cu. At all times, metal release concentrations in the water and citric acid treatments followed the trend of Mn>Cu>Fe. Rietveld analysis of x-ray diffraction data and ^31P NMR indicated that the metals substituted for Ca in the SHA structure. However, EPR data suggested that a metal (hydr)oxide phase existed either on the SHA surface or between the SHA crystallites. The metal concentration trend of Mn>Cu>Fe suggested that the initial solution metal concentrations are dependent on the dissolution of (hydr)oxides from SHA surfaces or between SHA crystallites. Similar metal concentrations at later times in the DTPA experiments suggests that metal concentrations were controlled by the release of Mn, Cu, or Fe from the SHA structure.

  20. Manganese.

    PubMed

    Barceloux, D G

    1999-01-01

    Manganese is a very hard, brittle metal, which is used to increase the strength of steel alloys. Absorption from the gastrointestinal tract occurs in the divalent and tetravalent forms. Permanganates, which are strong oxidizing agents, have a +7 valence. The principal organomanganese compound is the anti-knock additive, methylcyclopentadienyl manganese tricarbonyl. Manganese is a ubiquitous constituent of the environment comprising about 0.1% of the earth's crust. For the general population, food is the most important source of manganese with daily intake ranging from 2-9 mg Mn. Combustion of gasoline containing methylcyclopentadienyl manganese tricarbonyl releases submicron particles of Mn3O4 that are potentially respirable. Biomagnification of manganese in the food chain probably does not occur. The lungs and gastrointestinal tract absorb some manganese, but the relative amounts absorbed from each site are not known. Homeostatic mechanisms limit the absorption of manganese from the gastrointestinal tract. Elimination of manganese occurs primarily by excretion into the bile. Animal studies indicate that manganese is an essential co-factor for enzymes, such as hexokinase, superoxide dismutase, and xanthine oxidase. However, no case of manganese deficiency in humans has been identified. Manganism is a central nervous system disease first described in the 1800s following exposure to high concentrations of manganese oxides. Manganese madness was the term used to describe the initial psychiatric syndrome (compulsive behavior, emotional lability, hallucinations). More commonly, these workers developed a Parkinson's-like syndrome. Currently, the risks of exposure to low concentrations of manganese in the industrial and in the environmental settings (e.g., methylcyclopentadienyl manganese tricarbonyl in gasoline) are being evaluated with regards to the development of subclinical neuropsychological changes. The American Conference of Governmental and Industrial Hygienists recently lowered the TLV-TWA for manganese compounds and inorganic manganese compounds to 0.2 mg Mn/m3. PMID:10382563

  1. Manganese and iron both influence the shoot transcriptome of Typha angustifolia despite distinct preference towards manganese accumulation

    Microsoft Academic Search

    D. Chakraborty; S. Abhay Kumar; M. Sen; S. K. Apte; S. Das; R. Acharya; T. Das; A. V. R. Reddy; S. Roychaudhury; H. Rajaram; A. Seal

    2011-01-01

    Typha angustifolia is a metal hypertolerant grass that predominates the wetlands of uranium tailings in Jaduguda, India, contaminated with extreme\\u000a levels of iron (Fe) and manganese (Mn). In the paper investigations were carried out to understand the molecular mechanism\\u000a of metal tolerance in this tolerant macrophyte. Metal analysis was coupled with fluorescent differential display (FDD) and\\u000a reverse northern to compare

  2. Associations of Toenail Arsenic, Cadmium, Mercury, Manganese, and Lead with Blood Pressure in the Normative Aging Study

    PubMed Central

    Wright, Robert O.; Hu, Howard; Amarasiriwardena, Chitra; Baccarelli, Andrea; Litonjua, Augusto; Sparrow, David; Vokonas, Pantel; Schwartz, Joel

    2011-01-01

    Background: Arsenic, cadmium, mercury, and lead are associated with cardiovascular disease in epidemiologic research. These associations may be mediated by direct effects of the metals on blood pressure (BP) elevation. Manganese is associated with cardiovascular dysfunction and hypotension in occupational cohorts. Objectives: We hypothesized that chronic arsenic, cadmium, mercury, and lead exposures elevate BP and that manganese lowers BP. Methods: We conducted a cross-sectional analysis of associations between toenail metals and BP among older men from the Normative Aging Study (n = 639), using linear regression and adjusting for potential confounders. Results: An interquartile range increase in toenail arsenic was associated with higher systolic BP [0.93 mmHg; 95% confidence interval (CI): 0.25, 1.62] and pulse pressure (0.76 mmHg; 95% CI: 0.22, 1.30). Positive associations between arsenic and BP and negative associations between manganese and BP were strengthened in models adjusted for other toenail metals. Conclusions: Our findings suggest associations between BP and arsenic and manganese. This may be of public health importance because of prevalence of both metal exposure and cardiovascular disease. Results should be interpreted cautiously given potential limitations of toenails as biomarkers of metal exposure. PMID:21878420

  3. Recent research progress on iron- and manganese-based positive electrode materials for rechargeable sodium batteries

    NASA Astrophysics Data System (ADS)

    Yabuuchi, Naoaki; Komaba, Shinichi

    2014-08-01

    Large-scale high-energy batteries with electrode materials made from the Earth-abundant elements are needed to achieve sustainable energy development. On the basis of material abundance, rechargeable sodium batteries with iron- and manganese-based positive electrode materials are the ideal candidates for large-scale batteries. In this review, iron- and manganese-based electrode materials, oxides, phosphates, fluorides, etc, as positive electrodes for rechargeable sodium batteries are reviewed. Iron and manganese compounds with sodium ions provide high structural flexibility. Two layered polymorphs, O3- and P2-type layered structures, show different electrode performance in Na cells related to the different phase transition and sodium migration processes on sodium extraction/insertion. Similar to layered oxides, iron/manganese phosphates and pyrophosphates also provide the different framework structures, which are used as sodium insertion host materials. Electrode performance and reaction mechanisms of the iron- and manganese-based electrode materials in Na cells are described and the similarities and differences with lithium counterparts are also discussed. Together with these results, the possibility of the high-energy battery system with electrode materials made from only Earth-abundant elements is reviewed.

  4. Investigations of Cadmium Manganese Telluride Crystals for Room-temperature Radiation Detection

    SciTech Connect

    Yang, G.; Bolotnikov, A; Li, L; Camarda, G; Cui, Y; Hossain, A; Kim, K; Carcelen, V; Gul, R; James, R

    2010-01-01

    Cadmium manganese telluride (CMT) has high potential as a material for room-temperature nuclear-radiation detectors. We investigated indium-doped CMT crystals taken from the stable growth region of the ingot and compared its characteristics with that from the last-to-freeze region. We employed different techniques, including synchrotron white-beam x-ray topography (SWBXT), current-voltage (I-V) measurement, and low-temperature photoluminescence spectra, and we also assessed their responses as detectors of radiation exposure. The crystal from the stable growth region proved to be superior to that from the last-to-freeze region; it is a single-grain crystal, free of twins, and displayed a resistivity higher by one order of magnitude. The segregation of indium dopant in the ingot might be responsible for its better resistivity. Furthermore, we recorded a good response in the detector fabricated from the crystal taken from the stable growth region; its ({mu}{tau})e value was 2.6 x 10{sup -3} cm{sup 2}/V, which is acceptable for thin detectors, including their application in medicine.

  5. Transcriptional and biochemical effects of cadmium and manganese on the defense system of Octopus vulgaris paralarvae.

    PubMed

    Nicosia, Aldo; Salamone, Monica; Mazzola, Salvatore; Cuttitta, Angela

    2015-01-01

    Due to anthropogenic activities the relative concentrations of cadmium and manganese have increased in the marine environment. Cephalopods are able to accumulate such metals and, as inhabitant of coastal waters, Octopus vulgaris is continuously exposed to anthropogenic activities. Since no study is available on the effects of heavy metals at molecular level in developing octopuses, herein we exposed 1-day-old paralarvae for 24 h to 10, 100, and 1000 ?g/L of CdCl2 or MnCl2. Cd exerted a concentration-dependent inhibition of survival and a reduction in growth rate was shown while Mn exposure did not affect the survival rate even at the highest concentrations. Gene expression profiles of hsp70, sod, cat, and gst genes were analyzed by quantitative real-time PCR and defined patterns of transcription were observed. Moreover posttranscriptional analyses were also performed suggesting the impairment of metabolic functions, under strong oxidative conditions (as occurred in paralarvae exposed to Cd) or the complete detoxification events (as occurred in paralarvae exposed to Mn). PMID:25705660

  6. Occurrence and Distribution of Iron, Manganese, and Selected Trace Elements in Ground Water in the Glacial Aquifer System of the Northern United States

    USGS Publications Warehouse

    Groschen, George E.; Arnold, Terri L.; Morrow, William S.; Warner, Kelly L.

    2009-01-01

    Dissolved trace elements, including iron and manganese, are often an important factor in use of ground water for drinking-water supplies in the glacial aquifer system of the United States. The glacial aquifer system underlies most of New England, extends through the Midwest, and underlies portions of the Pacific Northwest and Alaska. Concentrations of dissolved trace elements in ground water can vary over several orders of magnitude across local well networks as well as across regions of the United States. Characterization of this variability is a step toward a regional screening-level assessment of potential human-health implications. Ground-water sampling, from 1991 through 2003, of the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey determined trace element concentrations in water from 847 wells in the glacial aquifer system. Dissolved iron and manganese concentrations were analyzed in those well samples and in water from an additional 743 NAWQA land-use and major-aquifer survey wells. The samples are from monitoring and water-supply wells. Concentrations of antimony, barium, beryllium, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, selenium, strontium, thallium, uranium, and zinc vary as much within NAWQA study units (local scale; ranging in size from a few thousand to tens of thousands of square miles) as over the entire glacial aquifer system. Patterns of trace element concentrations in glacial aquifer system ground water were examined by using techniques suitable for a dataset with zero to 80 percent of analytical results reported as below detection. During the period of sampling, the analytical techniques changed, which generally improved the analytical sensitivity. Multiple reporting limits complicated the comparison of detections and concentrations. Regression on Order Statistics was used to model probability distributions and estimate the medians and other quantiles of the trace element concentrations. Strontium and barium were the most frequently detected and usually were present in the highest concentrations. Iron and manganese were the next most commonly detected and next highest in concentrations. Iron concentrations were the most variable with respect to the range of variations (both within local networks and aquifer-wide) and with respect to the disparity between magnitude of concentrations (detections) and the frequency of samples below reporting limits (nondetections). Antimony, beryllium, cadmium, silver, and thallium were detected too infrequently for substantial interpretation of their occurrence or distributions or potential human-health implications. For those elements that were more frequently detected, there are some geographic patterns in their occurrence that primarily reflect climate effects. The highest concentrations of several elements were found in the West-Central glacial framework area (High Plains and northern Plains areas). There are few important patterns for any element in relation to land use, well type, or network type. Shallow land-use (monitor) wells had iron concentrations generally lower than the glacial aquifer system wells overall and much lower than major-aquifer survey wells, which comprise mostly private- and public-supply wells. Unlike those for iron, concentration patterns for manganese were similar among shallow land-use wells and major-aquifer survey wells. An apparent relation between low pH and relatively low concentrations of many elements, except lead, may be more indicative of the relatively low dissolved-solids content in wells in the Northeastern United States that comprise the majority of low pH wells, than of a pH dependent pattern. Iron and manganese have higher concentrations and larger ranges of concentrations especially under more reducing conditions. Dissolved oxygen and well depth were related to iron and manganese concentrations. Redox conditions also affect several trace elements such

  7. Cadmium depletes cellular iron availability through enhancing ferroportin translation via iron responsive element.

    PubMed

    Sun, Li; Wang, Lixin; Wang, Zhe; He, Wei; Zhang, Shuping; Guo, Wenli; Qian, Yi; Ji, Hong; Rong, Haiqin; Liu, Sijin

    2015-04-01

    Cadmium (Cd) is a heavy metal that has detrimental effects on various organs. The widespread contamination of Cd in the environment, crops and food sources poses a severe threat to human health. Acute toxicities of Cd have been extensively investigated; however, the health impact of chronic low?dose exposure to Cd, particularly exposure under non?toxic concentrations, has yet to be elucidated. Furthermore, the toxic threshold of Cd is currently unknown. Ferroportin is the only known iron exporter in vertebrate cells, and it has an essential role in controlling iron egress from cells. To the best of our knowledge, the present study is the first to verify the regulation of ferroportin by Cd. Treatment with low?dose Cd (i.e. at sublethal concentrations, without undermining cell viability) increased the protein expression of ferroportin in macrophages, and this was associated with depleted cellular iron levels. Mechanistic investigations revealed that Cd modulated the ferroportin concentration at the translational level, via the iron responsive element located at the 5'?untranslated region of ferroportin. In conclusion, these data provide evidence for the molecular basis by which Cd alters cellular iron availability through elevating concentrations of ferroportin. PMID:25435269

  8. Alteration of Serum Concentrations of Manganese, Iron, Ferritin, and Transferrin Receptor Following Exposure to Welding Fumes Among Career Welders

    PubMed Central

    Lu, Ling; Zhang, Long-lian; Li, G. Jane; Guo, Wenrui; Liang, Wannian; Zheng, Wei

    2014-01-01

    This study was performed to determine airborne manganese levels during welding practice and to establish the relationship between long-term, low-level exposure to manganese and altered serum concentrations of manganese, iron, and proteins associated with iron metabolism in career welders. Ninety-seven welders (average age of 36 years) who have engaged in electric arc weld in a vehicle manufacturer were recruited as the exposed group. Welders worked 7–8 h per day with employment duration of 1–33 years. Control subjects consisted of 91 employees (average age of 35 years) in the same factory but not in the welding profession. Ambient manganese levels in welders’ breathing zone were the highest inside the vehicle (1.5 ± 0.7 mg/m3), and the lowest in the center of the workshop (0.2 ± 0.05 mg/m3). Since the filter size was 0.8 ?m, it is possible that these values may be likely an underestimation of the true manganese levels. Serum levels of manganese and iron in welders were about three-fold (p < 0.01) and 1.2-fold (p < 0.01), respectively, higher than those of controls. Serum concentrations of ferritin and transferrin were increased among welders, while serum transferrin receptor levels were significantly decreased in comparison to controls. Linear regression analyses revealed a lack of association between serum levels of manganese and iron. However, serum concentrations of iron and ferritin were positively associated with years of welder experience (p < 0.05). Moreover, serum transferrin receptor levels were inversely associated with serum manganese concentrations (p < 0.05). These findings suggest that exposure to welding fume among welders disturbs serum homeostasis of manganese, iron, and the proteins associated with iron metabolism. Serum manganese may serve as a reasonable biomarker for assessment of recent exposure to airborne manganese. PMID:15713346

  9. Manganese accumulates in iron-deficient rat brain regions in a heterogeneous fashion and is associated with neurochemical alterations

    Microsoft Academic Search

    Keith M. Erikson; Zakariya K. Shihabi; Judy L. Aschner; Michael Aschner

    2002-01-01

    Previous studies have shown that iron deficiency (ID) increases brain manganese (Mn), but specific regional changes have not\\u000a been addressed. Weanling rats were fed one of three semipurified diets: control (CN), iron deficient (ID), or iron deficient\\/manganese\\u000a fortified (IDMn+). Seven brain regions were analyzed for Mn concentration and amino acid (glutamate, glutamine, taurine, ?-aminobutyric\\u000a acid) concentrations. Both ID and IDMn+

  10. Iron deficiency increases blood cadmium levels in adolescents surveyed in KNHANES 2010-2011.

    PubMed

    Lee, Byung-Kook; Kim, Suk Hwan; Kim, Nam-Soo; Ham, Jung-O; Kim, Yangho

    2014-06-01

    Discrepancies have been reported in the relationships between iron and cadmium concentrations. The distribution of blood cadmium concentrations was assessed in a representative sample of Korean adolescents participating in the Korean National Health and Nutritional Examination Survey (KNHANES) 2010-2011, and the association between blood cadmium and iron concentrations was determined. This study was based on data from KNHANES, in which a rolling sampling design was used to perform a complex, stratified, multistage probability cluster survey of a representative sample of the noninstitutionalized civilian population in South Korea. Serum ferritin was categorized as low (<15.0 ?g/L), low normal (15.0-<30.0 ?g/L for girls, 15.0-<50.0 ?g/L for boys), or normal (?30.0 ?g/L for girls, ?50.0 ?g/L for boys), and the association between serum ferritin and blood cadmium concentrations was assessed after adjustment for various demographic and lifestyle factors. The geometric mean (GM) of blood cadmium was significantly higher among both boys and girls in the low than in the normal ferritin group. After controlling for covariates, multiple regression analysis showed that blood cadmium concentration was inversely correlated with serum ferritin concentration in both boys and girls. In conclusion, iron deficiency is associated with increased blood cadmium concentrations in a representative sample of Korean adolescents, as evaluated in KNHANES. PMID:24797808

  11. Iron interactions and other biological reactions mediating the physiological and toxic actions of manganese

    Microsoft Academic Search

    Jerome A Roth; Michael D Garrick

    2003-01-01

    Chronic exposure to the divalent heavy metals, such as iron, lead, manganese (Mn), and chromium, has been linked to the development of severe, often irreversible neurological disorders and increased vulnerability to developing Parkinson’s disease. Although the mechanisms by which these metals elicit or facilitate neuronal cell death are not well defined, neurotoxicity is limited by the extent to which they

  12. Ammonia, iron and manganese removal from potable water using trickling filters

    Microsoft Academic Search

    A. G. Tekerlekopoulou; D. V. Vayenas

    2007-01-01

    Pilot scale trickling filters were constructed and tested in order to study biological removal of ammonia, iron and manganese from potable water. The effect of the size of the support material on nitrification performance was studied extensively. The mean size of the gravel and hence, the specific surface area was found to be critical for optimal nitrification operation. A steady-state

  13. Iron Deficient and Manganese Supplemented Diets Alter Metals and Transporters in the Developing Rat Brain

    Microsoft Academic Search

    Stephanie J. Garcia; Kristin Gellein; Tore Syversen; Michael Aschner

    2007-01-01

    Manganese (Mn) neurotoxicity in adults can result in psycho- logical and neurological disturbances similar to Parkinson's disease, including extrapyramidal motor system defects and altered behaviors. Iron (Fe) deficiency is one of the most prevalent nutritional disorders in the world, affecting approximately 2 billion people, especially pregnant and lactating women, infants, toddlers, and adolescents. Fe deficiency can enhance brain Mn accumulation

  14. Oxidant Selection for the Treatment of Manganese (II), Iron (II), and Arsenic (III) in Groundwaters

    EPA Science Inventory

    In order to comply with the United States Environmental Protection Agency?s (U.S. EPA?s) arsenic standard and the manganese and iron secondary maximum contaminant levels (MCLs) in water (10µg/L, 50µg/L, and 300µg/L, respectively), many Midwestern water utilities must add a strong...

  15. Influence of vegetative cycle of asparagus ( Asparagus officinalis L.) on copper, iron, zinc and manganese content

    Microsoft Academic Search

    M. A. Amaro-Lopez; G. Zurera-Cosano; R. Moreno-Rojas; R. M. Garcia-Gimeno

    1995-01-01

    The essential elements copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn) were analyzed in fresh asparagus to determine the effects of the vegetative cycle of the plant on the micronutrient content. Asparagus samples were classified in two groups by diameter (14 mm). Asparagus from a sample group with the same diameter were divided into two portions (apical and basal)

  16. STUDIES ON THE DETERMINATION OF TRACE OF ELEMENTS IN IRON AND STEELS. VII. SPECTROPHOTOMETRIC DETERMINATION OF MICRO AMOUNTS OF CADMIUM IN CAST IRON

    Microsoft Academic Search

    S. Maekawa; Y. Yoneyama

    1961-01-01

    An absorption photometric method for the determination of cadmium in ; cast iron by extraction as a dithizonate is described. The sample is decomposed ; by perchloric acid. After an addition of citric acid, ammonium hydroxide is ; added up to pH 9. Cadmium is extracted together with copper and nickel by ; dithizone --chloroform solution. From the extract, cadmium

  17. Potentiating effects of oxygen in lungs damaged by methylcyclopentadienyl manganese tricarbonyl, cadmium chloride, oleic acid, and antitumor drugs

    SciTech Connect

    Hakkinen, P.J.; Morse, C.C.; Martin, F.M.; Dalbey, W.E.; Haschek, W.M.; Witschi, H.R.

    1983-01-01

    The intraperitoneal administration of methylcyclopentadienyl manganese tricarbonyl (MMT) and cyclophosphamide, exposure to an aerosol of cadmium chloride, intravenous administration of oleic acid, and intratracheal instillation of bleomycin to young female BALB/c mice or CD/CR rats result in acute lung injury. Pulmonary morphology and lung collagen content were examined in animals treated with these chemicals alone or in combination with an elevated oxygen concentration (80%) in the inspired air. In mice, the development of fibrosis could be significantly enhanced if animals treated with MMT, cadmium chloride, cyclophosphamide, or bleomycin were exposed to 80% oxygen immediately following exposure to these agents. In rats only cyclophosphamide- and bleomycin-induced acute lung injury was potentiated by hyperoxia, resulting in significant enhancement of lung collagen content. The pathogenesis responsible for this differential species response of pulmonary injury to hyperoxia remains to be investigated.

  18. Lipid production combined with biosorption and bioaccumulation of cadmium, copper, manganese and zinc by oleaginous microalgae Chlorella minutissima UTEX2341.

    PubMed

    Yang, JinShui; Cao, Jing; Xing, GuanLan; Yuan, HongLi

    2014-11-01

    Algae lipid production combined with heavy metal removal is a cost-effective and environment-friendly method for algae biofuel production and hazardous waste treatment. Chlorella minutissima UTEX 2341 had strong resistance to cadmium, copper, manganese and zinc ions under heterotrophic culture condition and could efficiently remove them through intracellular accumulation and extracellular immobilization. Meanwhile, lipid accumulation was not inhibited by heavy metals. Instead, the algae lipid content significantly increased by 21.07% and 93.90%, respectively with the addition of cadmium and copper. Furthermore, the heavy metal residue in lipid was within ?g range and satisfied the commercial standard. This artificial wastewater-algae biofuel-heavy-metal integrated utilization technology offered a new alternative solution to the problems of energy shortage and environmental pollution. PMID:25459865

  19. Coprecipitation mechanisms and products in manganese oxidation in the presence of cadmium

    USGS Publications Warehouse

    Hem, J.D.; Lind, Carol J.

    1991-01-01

    Manganese oxidation products were precipitated in an aerated open-aqueous system where a continuous influx of mixed Mn2+ and Cd2+ solution was supplied and pH was maintained with an automated pH-stat adding dilute NaOH. X-ray diffraction and electron diffraction identified the solids produced as mixtures of Cd2Mn34+O8, Mn2+2Mn4+3O8, MnO2 (ramsdellite), and CdCO3. Mean oxidation numbers of the total precipitated Mn as great as 3.6 were reached during titrations. During subsequent aging in solution, oxidation numbers between 3.8 and 3.9 were reached in some precipitates in less than 40 days. Conditional oxidation rate constants calculated from a crystal-growth equation applied to titration data showed the overall precipitation rate, without considering manganese oxidation state in the precipitate, was increased by a factor of ~4 to ~7 when the mole ratio (Cd/Mn + Cd) of cadmium in the feed solution was 0.40 compared with rate constants for hausmannite (Mn2+Mn23+O4 precipitation under similar conditions but without accessory metals. Kinetic experiments were made to test effects of various Cd/Mn + Cd mole ratios and rates of addition of the feed solution, different temperatures from 5.0 to 35??C, and pH from 8.0 to 9.0. Oxidation rates were slower when the Cd mole ratio was less than 0.40. The rate increased by a factor of ~10 when pH was raised one-half unit. The effect of temperature on the rate constants was also substantial, but the meaning of this is uncertain because the rate of formation of Mn4+ oxide in the absence of Cd or other accessory metals was too slow to be measurable in titration experiments. The increased rate of Mn4+ oxide formation in the presence of Cd2+ can be ascribed to the formation of a labile adsorbed intermediate, CdMn2O4 Int, an analog of hausmannite, formed on precipitate surfaces at the beginning of the oxidation process. The increased lability of this structure, resulting from coordination-chemical behavior of Cd2+ during the titration, causes a rapid second-stage rearrangement and facilitates disproportionation of the Mn3+ ions. The Mn2+ ions thus released provide a positive feedback mechanism that couples the two steps of the conversion of Mn2+ to Mn4+ more closely than is possible when other metal ions besides manganese are not present. During aging of precipitates in contact with solutions, proportions of Cd2Mn3O8 and MnO2 increased at the expense of other precipitate components. ?? 1991.

  20. Microwave Resonance and Relaxation of Excess-Iron Manganese Ferrites

    Microsoft Academic Search

    Yoshiyuki Watanabe

    1973-01-01

    FMR measurements at 9.3 GHz have been made on single crystal disks of manganese ferrites with resistivities of the order of 0.1 \\\\varOmegacm (300 K), for various values of thickness. Comparison of the data with calculated absorption formulae indicates that an appreciable influence of skin depth effect remains until the thickness becomes as small as about 40 mum. This means

  1. Arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in feathers of Black-legged Kittiwake ( Rissa tridactyla) and Black Oystercatcher ( Haematopus bachmani) from Prince William Sound, Alaska

    Microsoft Academic Search

    Joanna Burger; Michael Gochfeld; Kelsey Sullivan; David Irons; Aly McKnight

    2008-01-01

    Arsenic, cadmium, chromium, lead, manganese, mercury and selenium were analyzed in the feathers of Black-legged Kittiwakes (Rissa tridactyla) from Shoup Bay in Prince William Sound, Alaska to determine if there were age-related differences in metal levels, and in Black Oystercatchers (Haematopus bachmani)) from the same region to determine if there were differences in oiled and unoiled birds. Except for mercury,

  2. A Simple Method Based on ICP-MS for Estimation of Background Levels of Arsenic, Cadmium, Copper, Manganese, Nickel, Lead, and Selenium in Blood of the Brazilian Population

    Microsoft Academic Search

    Juliana A. Nunes; Bruno L. Batista; Jairo L. Rodrigues; Naise M. Caldas; José A. G. Neto; Fernando Barbosa Jr

    2010-01-01

    Throughout the world, biomonitoring has become the standard for assessing exposure of individuals to toxic elements as well as for responding to serious environmental public health problems. However, extensive biomonitoring surveys require rapid and simple analytical methods. Thus, a simple and high-throughput method is proposed for the determination of arsenic (As), cadmium (Cd), copper (Cu), manganese (Mn), nickel (Ni), lead

  3. Maternal Exposure to Cadmium and Manganese Impairs Reproduction and Progeny Fitness in the Sea Urchin Paracentrotus lividus

    PubMed Central

    Migliaccio, Oriana; Castellano, Immacolata; Cirino, Paola; Romano, Giovanna; Palumbo, Anna

    2015-01-01

    Metal contamination represents one of the major sources of pollution in marine environments. In this study we investigated the short-term effects of ecologically relevant cadmium and manganese concentrations (10-6 and 3.6 x 10-5 M, respectively) on females of the sea urchin Paracentrotus lividus and their progeny, reared in the absence or presence of the metal. Cadmium is a well-known heavy metal, whereas manganese represents a potential emerging contaminant, resulting from an increased production of manganese-containing compounds. The effects of these agents were examined on both P. lividus adults and their offspring following reproductive state, morphology of embryos, nitric oxide (NO) production and differential gene expression. Here, we demonstrated that both metals differentially impaired the fertilization processes of the treated female sea urchins, causing modifications in the reproductive state and also affecting NO production in the ovaries. A detailed analysis of the progeny showed a high percentage of abnormal embryos, associated to an increase in the endogenous NO levels and variations in the transcriptional expression of several genes involved in stress response, skeletogenesis, detoxification, multi drug efflux processes and NO production. Moreover, we found significant differences in the progeny from females exposed to metals and reared in metal-containing sea water compared to embryos reared in non-contaminated sea water. Overall, these results greatly expanded previous studies on the toxic effects of metals on P. lividus and provided new insights into the molecular events induced in the progeny of sea urchins exposed to metals. PMID:26125595

  4. Associations of iron metabolism genes with blood manganese levels: a population-based study with validation data from animal models

    PubMed Central

    2011-01-01

    Background Given mounting evidence for adverse effects from excess manganese exposure, it is critical to understand host factors, such as genetics, that affect manganese metabolism. Methods Archived blood samples, collected from 332 Mexican women at delivery, were analyzed for manganese. We evaluated associations of manganese with functional variants in three candidate iron metabolism genes: HFE [hemochromatosis], TF [transferrin], and ALAD [?-aminolevulinic acid dehydratase]. We used a knockout mouse model to parallel our significant results as a novel method of validating the observed associations between genotype and blood manganese in our epidemiologic data. Results Percentage of participants carrying at least one copy of HFE C282Y, HFE H63D, TF P570S, and ALAD K59N variant alleles was 2.4%, 17.7%, 20.1%, and 6.4%, respectively. Percentage carrying at least one copy of either C282Y or H63D allele in HFE gene was 19.6%. Geometric mean (geometric standard deviation) manganese concentrations were 17.0 (1.5) ?g/l. Women with any HFE variant allele had 12% lower blood manganese concentrations than women with no variant alleles (? = -0.12 [95% CI = -0.23 to -0.01]). TF and ALAD variants were not significant predictors of blood manganese. In animal models, Hfe-/- mice displayed a significant reduction in blood manganese compared with Hfe+/+ mice, replicating the altered manganese metabolism found in our human research. Conclusions Our study suggests that genetic variants in iron metabolism genes may contribute to variability in manganese exposure by affecting manganese absorption, distribution, or excretion. Genetic background may be critical to consider in studies that rely on environmental manganese measurements. PMID:22074419

  5. OPT3 Is a Component of the Iron-Signaling Network between Leaves and Roots and Misregulation of OPT3 Leads to an Over-Accumulation of Cadmium in Seeds

    PubMed Central

    Mendoza-Cózatl, David G.; Xie, Qingqing; Akmakjian, Garo Z.; Jobe, Timothy O.; Patel, Ami; Stacey, Minviluz G.; Song, Lihui; Demoin, Dustin Wayne; Jurisson, Silvia S.; Stacey, Gary; Schroeder, Julian I.

    2014-01-01

    Plants and seeds are the main dietary sources of zinc, iron, manganese, and copper, but are also the main entry point for toxic elements such as cadmium into the food chain. We report here that an Arabidopsis oligopeptide transporter mutant, opt3-2, over-accumulates cadmium (Cd) in seeds and roots but, unexpectedly, under-accumulates Cd in leaves. The cadmium distribution in opt3-2 differs from iron, zinc, and manganese, suggesting a metal-specific mechanism for metal partitioning within the plant. The opt3-2 mutant constitutively up-regulates the Fe/Zn/Cd transporter IRT1 and FRO2 in roots, indicative of an iron-deficiency response. No genetic mutants that impair the shoot-to-root signaling of iron status in leaves have been identified. Interestingly, shoot-specific expression of OPT3 rescues the Cd sensitivity and complements the aberrant expression of IRT1 in opt3-2 roots, suggesting that OPT3 is required to relay the iron status from leaves to roots. OPT3 expression was found in the vasculature with preferential expression in the phloem at the plasma membrane. Using radioisotope experiments, we found that mobilization of Fe from leaves is severely affected in opt3-2, suggesting that Fe mobilization out of leaves is required for proper trace-metal homeostasis. When expressed in yeast, OPT3 does not localize to the plasma membrane, precluding the identification of the OPT3 substrate. Our in planta results show that OPT3 is important for leaf phloem-loading of iron and plays a key role regulating Fe, Zn, and Cd distribution within the plant. Furthermore, ferric chelate reductase activity analyses provide evidence that iron is not the sole signal transferred from leaves to roots in leaf iron status signaling. PMID:24880337

  6. OPT3 is a component of the iron-signaling network between leaves and roots and misregulation of OPT3 leads to an over-accumulation of cadmium in seeds.

    PubMed

    Mendoza-Cózatl, David G; Xie, Qingqing; Akmakjian, Garo Z; Jobe, Timothy O; Patel, Ami; Stacey, Minviluz G; Song, Lihui; Demoin, Dustin Wayne; Jurisson, Silvia S; Stacey, Gary; Schroeder, Julian I

    2014-09-01

    Plants and seeds are the main dietary sources of zinc, iron, manganese, and copper, but are also the main entry point for toxic elements such as cadmium into the food chain. We report here that an Arabidopsis oligopeptide transporter mutant, opt3-2, over-accumulates cadmium (Cd) in seeds and roots but, unexpectedly, under-accumulates Cd in leaves. The cadmium distribution in opt3-2 differs from iron, zinc, and manganese, suggesting a metal-specific mechanism for metal partitioning within the plant. The opt3-2 mutant constitutively up-regulates the Fe/Zn/Cd transporter IRT1 and FRO2 in roots, indicative of an iron-deficiency response. No genetic mutants that impair the shoot-to-root signaling of iron status in leaves have been identified. Interestingly, shoot-specific expression of OPT3 rescues the Cd sensitivity and complements the aberrant expression of IRT1 in opt3-2 roots, suggesting that OPT3 is required to relay the iron status from leaves to roots. OPT3 expression was found in the vasculature with preferential expression in the phloem at the plasma membrane. Using radioisotope experiments, we found that mobilization of Fe from leaves is severely affected in opt3-2, suggesting that Fe mobilization out of leaves is required for proper trace-metal homeostasis. When expressed in yeast, OPT3 does not localize to the plasma membrane, precluding the identification of the OPT3 substrate. Our in planta results show that OPT3 is important for leaf phloem-loading of iron and plays a key role regulating Fe, Zn, and Cd distribution within the plant. Furthermore, ferric chelate reductase activity analyses provide evidence that iron is not the sole signal transferred from leaves to roots in leaf iron status signaling. PMID:24880337

  7. Manganese exposure among smelting workers: blood manganese-iron ratio as a novel tool for manganese exposure assessment.

    PubMed

    Cowan, Dallas M; Fan, Qiyuan; Zou, Yan; Shi, Xiujuan; Chen, Jian; Aschner, Michael; Rosenthal, Frank S; Zheng, Wei

    2009-02-01

    Unexposed control subjects (n = 106), power distributing and office workers (n = 122), and manganese (Mn)-exposed ferroalloy smelter workers (n = 95) were recruited to the control, low and high groups, respectively. Mn concentrations in saliva, plasma, erythrocytes, urine and hair were significantly higher in both exposure groups than in the controls. The Fe concentration in plasma and erythrocytes, however, was significantly lower in Mn-exposed workers than in controls. The airborne Mn levels were significantly associated with Mn/Fe ratio (MIR) of erythrocytes (eMIR) (r = 0.77, p < 0.01) and plasma (pMIR) (r = 0.70, p < 0.01). The results suggest that the MIR may serve as a useful biomarker to distinguish Mn-exposed workers from the unexposed, control population. PMID:19283519

  8. Manganese exposure among smelting workers: blood manganese–iron ratio as a novel tool for manganese exposure assessment

    PubMed Central

    Cowan, Dallas M.; Fan, Qiyuan; Zou, Yan; Shi, Xiujuan; Chen, Jian; Aschner, Michael; Rosenthal, Frank S.; Zheng, Wei

    2014-01-01

    Unexposed control subjects (n = 106), power distributing and office workers (n = 122), and manganese (Mn)-exposed ferroalloy smelter workers (n = 95) were recruited to the control, low and high groups, respectively. Mn concentrations in saliva, plasma, erythrocytes, urine and hair were significantly higher in both exposure groups than in the controls. The Fe concentration in plasma and erythrocytes, however, was significantly lower in Mn-exposed workers than in controls. The airborne Mn levels were significantly associated with Mn/Fe ratio (MIR) of erythrocytes (eMIR) (r = 0.77, p < 0.01) and plasma (pMIR) (r = 0.70, p < 0.01). The results suggest that the MIR may serve as a useful biomarker to distinguish Mn-exposed workers from the unexposed, control population. PMID:19283519

  9. Manganese

    MedlinePLUS

    ... no RDAs for a nutrient, the Adequate Intake (AI) is used as a guide. The AI is the estimated amount of the nutrient that ... assumed to be adequate. The daily Adequate Intake (AI) levels for manganese are: infants birth to 6 ...

  10. The Association of Cobalt with Iron and Manganese (Oxyhydr)oxides in Marine Sediment

    Microsoft Academic Search

    Anthony Stockdale; William Davison; Hao Zhang; John Hamilton-Taylor

    2010-01-01

    Formation and dissolution of authigenic Fe and Mn (oxyhydr)oxides influence cycling of trace metals in oxic\\/suboxic surface\\u000a sediments. We used the diffusive gradients in thin films technique (DGT) to estimate the association of cobalt with iron and\\u000a manganese oxides. We compared Co, Fe and Mn maxima measured by DGT in the pore waters of fresh and aged marine sediment cores

  11. New Iron(II) and Manganese(II) Complexes of Two Ultra-Rigid, Cross-Bridged Tetraazamacrocycles for Catalysis and Biomimicry

    E-print Network

    Hubin, Tim

    New Iron(II) and Manganese(II) Complexes of Two Ultra-Rigid, Cross-Bridged Tetraazamacrocycles abstraction reactions. Introduction Manganese and iron share with copper dominance over the vast realm iron-based oxidation catalysis while Mn catalase,5 mitochondrial superoxide dismu- tase,6

  12. Iron and manganese in anaerobic respiration: environmental significance, physiology, and regulation

    NASA Technical Reports Server (NTRS)

    Nealson, K. H.; Saffarini, D.

    1994-01-01

    Dissimilatory iron and/or manganese reduction is known to occur in several organisms, including anaerobic sulfur-reducing organisms such as Geobacter metallireducens or Desulfuromonas acetoxidans, and facultative aerobes such as Shewanella putrefaciens. These bacteria couple both carbon oxidation and growth to the reduction of these metals, and inhibitor and competition experiments suggest that Mn(IV) and Fe(III) are efficient electron acceptors similar to nitrate in redox abilities and capable of out-competing electron acceptors of lower potential, such as sulfate (sulfate reduction) or CO2 (methanogenesis). Field studies of iron and/or manganese reduction suggest that organisms with such metabolic abilities play important roles in coupling the oxidation of organic carbon to metal reduction under anaerobic conditions. Because both iron and manganese oxides are solids or colloids, they tend to settle downward in aquatic environments, providing a physical mechanism for the movement of oxidizing potential into anoxic zones. The resulting biogeochemical metal cycles have a strong impact on many other elements including carbon, sulfur, phosphorous, and trace metals.

  13. Iron and manganese in anaerobic respiration: environmental significance, physiology, and regulation.

    PubMed

    Nealson, K H; Saffarini, D

    1994-01-01

    Dissimilatory iron and/or manganese reduction is known to occur in several organisms, including anaerobic sulfur-reducing organisms such as Geobacter metallireducens or Desulfuromonas acetoxidans, and facultative aerobes such as Shewanella putrefaciens. These bacteria couple both carbon oxidation and growth to the reduction of these metals, and inhibitor and competition experiments suggest that Mn(IV) and Fe(III) are efficient electron acceptors similar to nitrate in redox abilities and capable of out-competing electron acceptors of lower potential, such as sulfate (sulfate reduction) or CO2 (methanogenesis). Field studies of iron and/or manganese reduction suggest that organisms with such metabolic abilities play important roles in coupling the oxidation of organic carbon to metal reduction under anaerobic conditions. Because both iron and manganese oxides are solids or colloids, they tend to settle downward in aquatic environments, providing a physical mechanism for the movement of oxidizing potential into anoxic zones. The resulting biogeochemical metal cycles have a strong impact on many other elements including carbon, sulfur, phosphorous, and trace metals. PMID:7826009

  14. Cadmium

    Cancer.gov

    Cadmium is a natural element found in tiny amounts in air, water, soil, and food. All soils and rocks, including coal and mineral fertilizers, contain some cadmium. Most cadmium used in the United States is extracted during the production of other metals such as zinc, lead, and copper. Cadmium does not corrode easily and has been used to manufacture batteries, pigments, metal coatings, and plastics.

  15. Iron and copper accumulation in the brain of coxsackievirus-infected mice exposed to cadmium

    Microsoft Academic Search

    N.-G.. Ilbaeck; U. Lindh; R. Minqin; G. Friman; F. Watt

    2006-01-01

    Cadmium (Cd) is a potentially toxic metal widely distributed in the environment and known to cause adverse health effects in humans. During coxsackievirus infection, the concentrations of essential and nonessential trace elements (e.g., iron (Fe), copper (Cu), and Cd) change in different target organs of the infection. Fe and Cu are recognized cofactors in host defence reactions, and Fe is

  16. THE EFFECTS OF IRON(II) ON ARSENIC(III) OXIDATION AND ARSENIC SORPTION/DESORPTION ON MANGANESE OXIDES

    E-print Network

    Sparks, Donald L.

    THE EFFECTS OF IRON(II) ON ARSENIC(III) OXIDATION AND ARSENIC SORPTION/DESORPTION ON MANGANESE © 2014 Yun Wu All Rights Reserved #12;THE EFFECTS OF IRON(II) ON ARSENIC(III) OXIDATION AND ARSENIC, Caroline Golt on arsenic speciation and UD Soil Test Lab. I thank all current and previous members

  17. Assessment of metals in down feathers of female common eiders and their eggs from the Aleutians: arsenic, cadmium, chromium, lead, manganese, mercury, and selenium

    PubMed Central

    Burger, Joanna; Gochfeld, Michael; Jeitner, Christian; Snigaroff, Daniel; Snigaroff, Ronald; Stamm, Timothy; Volz, Conrad

    2014-01-01

    Concentrations of arsenic, cadmium, chromium, lead, manganese, mercury and selenium were examined in the down feathers and eggs of female common eiders (Somateria mollissima) from Amchitka and Kiska Islands in the Aleutian Chain of Alaska to determine whether there were (1) differences between levels in feathers and eggs, (2) differences between the two islands, (3) positive correlations between metal levels in females and their eggs, and (4) whether there was more variation within or among clutches. Mean levels in eggs (dry weight) were as follows: arsenic (769 ppb, ng/g), cadmium (1.49 ppb), chromium (414 ppb), lead (306 ppb), manganese (1,470 ppb), mercury (431 ppb) and selenium (1,730 ppb). Levels of arsenic were higher in eggs, while chromium, lead, manganese, and mercury were higher in feathers; there were no differences for selenium. There were no significant interisland differences in female feather levels, except for manganese (eider feathers from Amchitka were four times higher than feathers from Kiska). Levels of manganese in eggs were also higher from Amchitka than Kiska, and eider eggs from Kiska had significantly higher levels of arsenic, but lower levels of selenium. There were no significant correlations between the levels of any metals in down feathers of females and in their eggs. The levels of mercury in eggs were below ecological benchmark levels, and were below human health risk levels. However, Aleuts can seasonally consume several meals of bird eggs a week, suggesting cause for concern for sensitive (pregnant) women. PMID:17934788

  18. Intestinal absorption of dietary cadmium in women depends on body iron stores and fiber intake.

    PubMed Central

    Berglund, M; Akesson, A; Nermell, B; Vahter, M

    1994-01-01

    Measurements of intake and uptake of cadmium in relation to diet composition were carried out in 57 nonsmoking women, 20-50 years of age. A vegetarian/high-fiber diet and a mixed-diet group were constructed based on results from a food frequency questionnaire. Duplicate diets and the corresponding feces were collected during 4 consecutive days in parallel with dietary recording of type and amount of food ingested for determination of the dietary intake of cadmium and various nutrients. Blood and 24-hr urine samples were collected for determination of cadmium, hemoglobin, ferritin, and zinc. There were no differences in the intake of nutrients between the mixed-diet and the high-fiber diet groups, except for a significantly higher intake of fiber (p < 0.001) and cadmium (p < 0.002) in the high-fiber group. Fecal cadmium corresponded to 98% in the mixed-diet group and 100% in the high-fiber diet group. No differences in blood cadmium (BCd) or urinary cadmium (UCd) between groups could be detected. There was a tendency toward higher BCd and UCd concentrations with increasing fiber intake; however, the concentrations were not statistically significant at the 5% level, indicating an inhibitory effect of fiber on the gastrointestinal absorption of cadmium. Sixty-seven percent of the women had serum ferritin < 30 micrograms/l, indicating reduced body iron stores, which were highly associated with higher BCd (irrespective of fiber intake). BCd was mainly correlated with UCd, serum ferritin, age, anf fibre intake. UCd and serum ferritin explained almost 60% of the variation in BCd.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 1. Figure 2. Figure 3. A Figure 3. B Figure 4. Figure 5. PMID:7713018

  19. [Spectroscopic analysis of substituted tetraphenylporphyrin iron, manganese, cobalt, copper and zinc complexes].

    PubMed

    Wang, Lan-zhi; She, Yuan-bin

    2008-10-01

    A full IR, UV-Vis, FIR, spectroscopic analysis on substituted porphyrin iron, manganese, cobalt, copper and Zinc complexes was performed, and the spectroscopic patterns were found for the metalloporphyrin compounds with various structures. Base on molecular structures theory, the reasons for the spectroscopic patterns were discussed deeply. Considering the inconsistency of the far-infrared spectra of the Fe-Cl axial bonds in chloro-iron tetraphenylporphyrins reported in the literature. Their far-infrared absorptions were investigated by using both theoretical analysis and experimental determination, and the results showing that their vibrational frequencies of the Fe--Cl bonds in different substitution chloro-iron tetraphenylporphyrins were associated with their structures, and were linearly related to the length of Fe--Cl bonds. PMID:19123396

  20. The photochemistry of manganese and the origin of banded iron formations

    NASA Technical Reports Server (NTRS)

    Anbar, A. D.; Holland, H. D.

    1992-01-01

    The origin of the deposition of superior-type Precambrian banded iron formations (BIFs) is investigated in experiments where the effect of UV radiation on dissolved manganese was studied to determine if the commonly accepted photochemical model for BIF formation is consistent with the distribution of Mn in BIFs. Solutions containing 0.56 M NaCl and about 180 microM MnCl2, with or without 3 to 200 microM FeCl2 were irradiated with filtered and unfiltered UV light for up to 8 hrs; the solutions were deaerated and buffered to a pH of 7, and the experiments were conducted under oxygen-free atmosphere. Data on the rate of manganese photooxidation confirmed that a photochemical model for the origin of oxide facies BIFs is consistent with field observations.

  1. Thermodynamic and kinetic studies of biosorption of iron and manganese from aqueous medium using rice husk ash

    NASA Astrophysics Data System (ADS)

    Adekola, F. A.; Hodonou, D. S. S.; Adegoke, H. I.

    2014-11-01

    The adsorption behavior of rice husk ash with respect to manganese and iron has been studied by batch methods to consider its application for water and waste water treatment. The optimum conditions of adsorption were determined by investigating the effect of initial metal ion concentration, contact time, adsorbent dose, pH value of aqueous solution and temperature. Adsorption equilibrium time was observed at 120 min. The adsorption efficiencies were found to be pH dependent. The equilibrium adsorption experimental data were found to fit the Langmuir, Freundlich and Temkin isotherms for iron, but fitted only Langmuir isotherm for manganese. The pseudo-second order kinetic model was found to describe the manganese and iron kinetics more effectively. The thermodynamic experiment revealed that the adsorption processes involving both metals were exothermic. The adsorbent was finally applied to typical raw water with initial manganese and iron concentrations of 3.38 mg/l for Fe and 6.28 mg/l, respectively, and the removal efficiency was 100 % for Mn and 70 % for Fe. The metal ions were desorbed from the adsorbent using 0.01 M HCl, it was found to quantitatively remove 67 and 86 % of Mn and Fe, respectively, within 2 h. The results revealed that manganese and iron are considerably adsorbed on the adsorbent and could be an economic method for the removal of these metals from aqueous solutions.

  2. Removal of iron and manganese by artificial destratification in a tropical climate (Upper Layang Reservoir, Malaysia).

    PubMed

    Ismail, R; Kassim, M A; Inman, M; Baharim, N H; Azman, S

    2002-01-01

    Environmental monitoring was carried out at Upper Layang Reservoir situated in Masai, Johor, Malaysia. The study shows that thermal stratification and natural mixing of the water column do exist in the reservoir and the level of stratification varies at different times of the year. Artificial destratification via diffused air aeration techniques was employed at the reservoir for two months. The results show that thermal stratification was eliminated after a week of continuous aeration. The concentrations of iron and to a lesser extent manganese in the water column was also reduced during the aeration period. PMID:12448467

  3. Iron-manganese binary oxide coated functionalized multiwalled carbon nanotubes for arsenic removal

    NASA Astrophysics Data System (ADS)

    Tamilarasan, P.; Ramaprabhu, S.

    2012-06-01

    In the present study, we report, iron-manganese based amorphous binary oxide coated functionalized multiwalled carbon nanotubes (f-MWNTs) as an efficient adsorbent for arsenic removal. The Fe-Mn binary oxide/f-MWNTs (FeMn/f-MWNT) has been synthesized by co-precipitation of both oxides in the presence of f-MWNTs and characterized. The arsenic (both arsenate and arsenite) adsorption capacity of the nanocomposite has been studied by batch adsorption method at pH around 7. Langmuir and Elovich equations were used to extract the isotherm and kinetic constants, respectively. This nanocomposite shows fast adsorption kinetics and high adsorption capacity.

  4. Biomimetic degradation of lignin and lignin model compounds by synthetic anionic and cationic water soluble manganese and iron porphyrins.

    PubMed

    Crestini, C; Saladino, R; Tagliatesta, P; Boschi, T

    1999-09-01

    The biomimetic oxidation of 5-5' condensed and diphenylmethane lignin model compounds with several water soluble anionic and cationic iron and manganese porphyrins in the presence of hydrogen peroxide is reported. The oxidative efficiency of manganese and iron meso-tetra(2,6-dichloro-3-sulphonatophenyl) porphyrin chloride (TDCSPPMnCl and TDCSPPFeCl, respectively), meso-tetra-3-sulphonatophenyl porphyrin chloride (TSPPMnCl) and manganese meso-tetra(N-methylpyridinio)porphyrin pentaacetate (TPyMePMn(CH3COO)5) was compared on the basis of the oxidation extent of the models tested. Manganese porphyrins were found more effective in degrading lignin substructures than iron ones. Among them the cationic TPyMePMn (CH3COO)5, never used before in lignin oxidation, showed to be the best catalyst. The catalytic activity of porphyrins in hydrogen peroxide oxidation of residual kraft lignin was also investigated. The use of quantitative 31P NMR allowed the focusing on the occurrence of different degradative pathways depending on the catalyst used. TPyMePMn(CH3COO)5 was able to perform the most extensive degradation of the lignin structure, as demonstrated by the decrease of aliphatic hydroxyl groups and carboxylic acids. Noteworthy, no significant condensation reactions occurred during manganese porphyrins catalyzed oxidations of residual kraft lignin, while in the presence of iron porphyrins a substantial increase of condensed substructures was detected. PMID:10530938

  5. Growth and Dissolution of Iron and Manganese Oxide Films

    SciTech Connect

    Scot T. Martin

    2008-12-22

    Growth and dissolution of Fe and Mn oxide films are key regulators of the fate and transport of heavy metals in the environment, especially during changing seasonal conditions of pH and dissolved oxygen. The Fe and Mn are present at much higher concentrations than the heavy metals, and, when Fe and Mn precipitate as oxide films, heavy metals surface adsorb or co-precipitate and are thus essentially immobilized. Conversely, when the Fe and Mn oxide films dissolve, the heavy metals are released to aqueous solution and are thus mobilized for transport. Therefore, understanding the dynamics and properties of Fe and Mn oxide films and thus on the uptake and release of heavy metals is critically important to any attempt to develop mechanistic, quantitative models of the fate, transport, and bioavailablity of heavy metals. A primary capability developed in our earlier work was the ability to grow manganese oxide (MnO{sub x}) films on rhodochrosite (MnCO{sub 3}) substrate in presence of dissolved oxygen under mild alkaline conditions. The morphology of the films was characterized using contact-mode atomic force microscopy. The initial growth began by heteroepitaxial nucleation. The resulting films had maximum heights of 1.5 to 2 nm as a result of thermodynamic constraints. Over the three past years, we have investigated the effects of MnO{sub x} growth on the interactions of MnCO{sub 3} with charged ions and microorganisms, as regulated by the surface electrical properties of the mineral. In 2006, we demonstrated that MnO{sub x} growth could induce interfacial repulsion and surface adhesion on the otherwise neutral MnCO{sub 3} substrate under environmental conditions. Using force-volume microscopy (FVM), we measured the interfacial and adhesive forces on a MnO{sub x}/MnCO{sub 3} surface with a negatively charged silicon nitride tip in a 10-mM NaNO3 solution at pH 7.4. The interfacial force and surface adhesion of MnOx were approximately 40 pN and 600 pN, respectively, whereas those of MnCO{sub 3} were essentially zero. The force differences between MnO{sub x} and MnCO{sub 3} suggest that oxide film growth can focus adsorbates to certain parts of the surface and thereby templating a heterogeneous layout of them. We suspected that the force differences were in part due to the differences in surface electrical properties. In 2007, we investigated two important electrical properties of MnO{sub x} and MnCO{sub 3} surfaces, namely surface potential and ion mobility. Surface potential is a composite quantity that can be linked to the local lattice structure of the reconstructed surface and the adsorption of water layers. The mobile surface ions formed by dissolution can also contribute to surface potential. Using Kelvin probe force microscopy (KPFM) and scanning polarization force microscopy (SPFM), we found that MnOx possessed excess surface potentials of over +200 mV in humid nitrogen and the excess surface potential decreased with increasing relative humidity (i.e., increasing adsorbed water layers on the mineral surface). The dependence of the excess surface potential was attributed to the change of the contributions from mobile ions. These results supported our earlier hypothesis that MnO{sub x} and MnCO{sub 3} had different surface electrical properties. In the third year, we systematically characterized that the change of the electrical double layer (EDL) structure of MnCO{sub 3} surface due to MnO{sub x} growth in aqueous solution and its dependence on pH. The structure of the electrical double layer determines the electrostatic interactions between the mineral surface and charged adsorbates. As described by the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, the electrostatic force, together with van der Waals interaction, regulates surface adsorption and bacterial attachment. Once adsorbates establish contact with the surface, they must resist hydraulic shear forces through surface adhesion. The adhesion of mineral surfaces is also affected by their electrostatic interactions with adsorbates. To probe the EDL structure, we ap

  6. Effect of cadmium on iron uptake in cucumber roots: A Mössbauer-spectroscopic study

    Microsoft Academic Search

    Krisztina Kovács; Ern? Kuzmann; Attila Vértes; László Lévai; Ferenc Fodor

    2010-01-01

    The uptake and accumulation of iron in cucumber roots exposed to cadmium were investigated with Fe sufficient and deficient\\u000a cucumber plants using Mössbauer spectroscopy, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and ferric chelate reductase\\u000a activity measurements. Both Fe sufficient and Fe deficient plants were applied. In the case of Fe sufficient cucumber roots\\u000a grown in nutrient solution with 10 ?M Cd

  7. Effects of Exogenous Gibberellic Acid3 on Iron and Manganese Plaque Amounts and Iron and Manganese Uptake in Rice

    PubMed Central

    Guo, Yue; Zhu, Changhua; Gan, Lijun; Ng, Denny; Xia, Kai

    2015-01-01

    Gibberellins (GA) regulate various components of plant development. Iron and Mn plaque result from oxiding and hydroxiding Fe and Mn, respectively, on the roots of aquatic plant species such as rice (Oryza sativa L.). In this study, we found that exogenous gibberellic acid3 (GA3) spray decreased Fe plaque, but increased Mn plaque, with applications of Kimura B nutrient solution. Similar effects from GA3, leading to reduced Fe plaque and increased Mn plaque, were also found by scanning electron microscopy and energy dispersive X-ray spectrometric microanalysis. Reduced Fe plaque was observed after applying GA3 to the groups containing added Fe2+ (17 and 42 mg•L-1) and an increasing trend was detected in Mn plaques of the Mn2+ (34 and 84 mg•L-1) added treatments. In contrast, an inhibitor of GA3, uniconazole, reversed the effects of GA3. The uptake of Fe or Mn in rice plants was enhanced after GA3 application and Fe or Mn plaque production. Strong synergetic effects of GA3 application on Fe plaque production were detected. However, no synergetic effects on Mn plaque production were detected. PMID:25710173

  8. Studies on the role of iron in the reversal of zinc, cadmium, vanadium, nickel, and cobalt toxicities in boiler pullets

    Microsoft Academic Search

    Blalock

    1986-01-01

    Excess dietary iron reduced the toxicity of cadmium (Cd), cobalt (Co), nickel (Ni) and vanadium (V) in chicks. In order to gain further insight into this phenomenon, the toxicity of these elements was examined under conditions of dietary iron deficiency, ca. 10 ppm, and excess, ca. 1010 ppm. Graded levels of Cd, Co, Ni, V and also of zinc (Zn)

  9. Cadmium and manganese accumulation in Phytolacca americana L. and the roles of non-protein thiols and organic acids.

    PubMed

    Gao, Lu; Peng, Kejian; Xia, Yan; Wang, Guiping; Niu, Liyuan; Lian, Chunlan; Shen, Zhenguo

    2013-01-01

    Phytolacca americana L. can accumulate large amounts of heavy metals in its aerial tissues, especially cadmium (Cd) and manganese (Mn). It has great potential for use in phytoextraction of metals from multi-metal-contaminated soils. This study was conducted to further investigate the Cd- and Mn-tolerance strategies of this plant. Concentrations of non-protein thiols (NPTs) and phytochelatins (PCs) in leaves and roots increased significantly as the concentration of Cd in solution increased. The molar ratios of PCs:soluble Cd ranged from 1.8 to 3.6 in roots and 8.1 to 31.6 in leaves, suggesting that the cellular response involving PC synthesis was sufficient to complex Cd ions in the cytosol, especially that of leaves. In contrast, excess Mn treatments did not result in a significant increase in NPT or PC concentrations in leaves or roots. Oxalic acid concentrations in leaves of plants exposed to 2 or 20 mM Mn reached 69.4 to 89.3 mg (0.771 to 0.992 mmol) g(-1) dry weight, respectively, which was approximately 3.7- to 8.6-fold higher than the Mn level in the 0.6 M HCl extract. Thus, oxalic acid may play an important role in the detoxification of Mn. PMID:23487997

  10. Deriving freshwater quality criteria for copper, cadmium, aluminum and manganese for protection of aquatic life in Malaysia.

    PubMed

    Shuhaimi-Othman, M; Nadzifah, Y; Nur-Amalina, R; Umirah, N S

    2013-03-01

    Freshwater quality criteria for copper (Cu), cadmium (Cd), aluminum (Al), and manganese (Mn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia, which were Macrobrachiumlanchesteri (prawn), two fish -Poeciliareticulata and Rasborasumatrana, Melanoidestuberculata (snail), Stenocyprismajor (ostracod), Chironomusjavanus (midge larvae), Naiselinguis (annelid), and Duttaphrynusmelanostictus (tadpole), to determine 96-h LC50 values for Cu, Cd, Al, and Mn. The final acute values (FAVs) for Cu, Cd, Al, and Mn were 2.5, 3.0, 977.8, and 78.3 ?gL(-1), respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a Criterion Maximum Concentration (CMC) and a criterion Continuous Concentration (CCC) for Cu, Cd, Al, and Mn of 1.3, 1.5, 488.9, and 39.1 ?gL(-1) and 0.3, 0.36, 117.8, and 9.4 ?gL(-1), respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Cu, Cd, Al, and Mn based on aquatic biota in Malaysia. Based on LC50 values, this study indicated that R.sumatrana, M.lanchesteri, C.javanus, and N.elinguis were the most sensitive to Cu, Cd, Al, and Mn, respectively. PMID:23246727

  11. Early onset of virus infection and up-regulation of cytokines in mice treated with cadmium and manganese.

    PubMed

    Seth, Pankaj; Husain, Mirza M; Gupta, Pratibha; Schoneboom, A; Grieder, Bruce Franziska B; Mani, Haresh; Maheshwari, Radha K

    2003-06-01

    A substantial database indicates that a large number of environmental pollutants, chemicals and therapeutic agents to which organisms are exposed cause immunotoxicity. The suppression of immune functions may cause increased susceptibility of the host to a variety of microbial pathogens potentially resulting in a life-threatening state. Evaluation of the immunotoxic potential of chemical xenobiotics is of great concern and, therefore, we have investigated the impact of exposure of inorganic metals, specifically cadmium (Cd) and manganese (Mn) on Encephalomyocarditis virus (EMCV), Semliki Forest virus (SFV), and Venezuelan Equine Encephalitis virus (VEEV) infection. Pretreatment with a single, oral dose of Cd or Mn increased the susceptibility of mice to a sub-lethal infection of these viruses as observed by increased severity of symptoms and mortality compared to untreated controls. An early onset of virus infection was found in brains of Cd and Mn treated animals. Histopathological observations of the brain indicate evidence of inflammation and greater tissue pathology in Cd-or Mn-exposed mice compared to control animals. Meningitis and vascular congestion was seen in virus infected mice in all the metal treated groups, and further, the perivascular inflammation appeared earlier in treated mice compared to control. Encephalitis was maximum in Cd pretreated mice. Widespread environmental contamination of metals and the potential for their exposure and subsequent infection of humans or animals is indicative that further studies of these and all other metals are important to understand the effect of environmental pollution on human health. PMID:12572694

  12. Ozone decomposition and benzene oxidation catalysts based on iron and manganese oxides as industrial wastes from water decontamination by ozone treatment

    Microsoft Academic Search

    L. A. Zaloznaya; S. N. Tkachenko; G. V. Egorova; I. S. Tkachenko; A. V. Sobolev; E. Z. Golosman; V. A. Troshina; V. V. Lunin

    2009-01-01

    Effective ozone decomposition catalysts were created on the basis of iron oxides as side products from natural water treated\\u000a with ozone at water treatment plants. Iron oxide catalysts doped with manganese oxide are by 40% more active in benzene oxidation.\\u000a These iron-manganese catalysts can be recommended for industrial manufacture by the designed technologies and application\\u000a in ozone decomposition and benzene

  13. Arsenic, Iron, Lead, Manganese and Uranium Concentrations in Private Bedrock Wells in Southeastern New Hampshire, 2012-2013

    EPA Science Inventory

    Trace metals, such as arsenic, iron, lead, manganese, and uranium, in groundwater used for drinking have long been a concern because of the potential adverse effects on human health and the aesthetic or nuisance problems that some present. Moderate to high concentrations of the t...

  14. Uptake of iron, zinc, manganese, and copper by seedlings of hybrid and traditional rice cultivars from different soil types

    Microsoft Academic Search

    X. Yang; V. Römheld; H. Marschner

    1994-01-01

    In pot experiments, uptake of zinc (Zn), copper (Cu), iron (Fe), and manganese (Mn) by hybrid rice from different soil types was compared with a traditional rice (Oryza sativa L.) cultivar. The concentration and total uptake of Fe in the shoots of hybrid rice grown in Oxisol and Ultisol were lower than those of the traditional cultivar. The concentration and

  15. SOLID PHASE SPECIATION OF IRON AND MANGANESE IN ALUM SHALE SOILS STUDIED BY PARALLEL AND SEQUENTIAL EXTRACTION

    Microsoft Academic Search

    R. P. Narwall; B. R. Singh

    2001-01-01

    The kind of association of heavy metals with soil components determines the mobility and availability of metals in soils. It is, therefore, necessary to understand and differentiate the different physicochemical forms of metals. A laboratory study was conducted to investigate the solubility of iron (Fe) and manganese (Mn) and their association with soil components by the newly developed sequential extraction

  16. Iron-Mediated Inhibition of Mitochondrial Manganese Uptake Mediates Mitochondrial Dysfunction in a Mouse Model of Hemochromatosis

    PubMed Central

    Jouihan, Hani A; Cobine, Paul A; Cooksey, Robert C; Hoagland, Emily A; Boudina, Sihem; Abel, E Dale; Winge, Dennis R; McClain, Donald A

    2008-01-01

    Previous phenotyping of glucose homeostasis and insulin secretion in a mouse model of hereditary hemochromatosis (Hfe?/?) and iron overload suggested mitochondrial dysfunction. Mitochondria from Hfe?/? mouse liver exhibited decreased respiratory capacity and increased lipid peroxidation. Although the cytosol contained excess iron, Hfe?/? mitochondria contained normal iron but decreased copper, manganese, and zinc, associated with reduced activities of copper-dependent cytochrome c oxidase and manganese-dependent superoxide dismutase (MnSOD). The attenuation in MnSOD activity was due to substantial levels of unmetallated apoprotein. The oxidative damage in Hfe?/? mitochondria is due to diminished MnSOD activity, as manganese supplementation of Hfe?/? mice led to enhancement of MnSOD activity and suppressed lipid peroxidation. Manganese supplementation also resulted in improved insulin secretion and glucose tolerance associated with increased MnSOD activity and decreased lipid peroxidation in islets. These data suggest a novel mechanism of iron-induced cellular dysfunction, namely altered mitochondrial uptake of other metal ions. PMID:18317567

  17. Iron-mediated inhibition of mitochondrial manganese uptake mediates mitochondrial dysfunction in a mouse model of hemochromatosis.

    PubMed

    Jouihan, Hani A; Cobine, Paul A; Cooksey, Robert C; Hoagland, Emily A; Boudina, Sihem; Abel, E Dale; Winge, Dennis R; McClain, Donald A

    2008-01-01

    Previous phenotyping of glucose homeostasis and insulin secretion in a mouse model of hereditary hemochromatosis (Hfe(-/-)) and iron overload suggested mitochondrial dysfunction. Mitochondria from Hfe(-/-) mouse liver exhibited decreased respiratory capacity and increased lipid peroxidation. Although the cytosol contained excess iron, Hfe(-/-) mitochondria contained normal iron but decreased copper, manganese, and zinc, associated with reduced activities of copper-dependent cytochrome c oxidase and manganese-dependent superoxide dismutase (MnSOD). The attenuation in MnSOD activity was due to substantial levels of unmetallated apoprotein. The oxidative damage in Hfe(-/-) mitochondria is due to diminished MnSOD activity, as manganese supplementation of Hfe(-/-) mice led to enhancement of MnSOD activity and suppressed lipid peroxidation. Manganese supplementation also resulted in improved insulin secretion and glucose tolerance associated with increased MnSOD activity and decreased lipid peroxidation in islets. These data suggest a novel mechanism of iron-induced cellular dysfunction, namely altered mitochondrial uptake of other metal ions. PMID:18317567

  18. Bacterial Disproportionation of Elemental Sulfur Coupled to Chemical Reduction of Iron or Manganese

    PubMed Central

    Thamdrup, Bo; Finster, Kai; Hansen, Jens Würgler; Bak, Friedhelm

    1993-01-01

    A new chemolithotrophic bacterial metabolism was discovered in anaerobic marine enrichment cultures. Cultures in defined medium with elemental sulfur (S0) and amorphous ferric hydroxide (FeOOH) as sole substrates showed intense formation of sulfate. Furthermore, precipitation of ferrous sulfide and pyrite was observed. The transformations were accompanied by growth of slightly curved, rod-shaped bacteria. The quantification of the products revealed that S0 was microbially disproportionated to sulfate and sulfide, as follows: 4S0 + 4H2O ? SO42- + 3H2S + 2H+. Subsequent chemical reactions between the formed sulfide and the added FeOOH led to the observed precipitation of iron sulfides. Sulfate and iron sulfides were also produced when FeOOH was replaced by FeCO3. Further enrichment with manganese oxide, MnO2, instead of FeOOH yielded stable cultures which formed sulfate during concomitant reduction of MnO2 to Mn2+. Growth of small rod-shaped bacteria was observed. When incubated without MnO2, the culture did not grow but produced small amounts of SO42- and H2S at a ratio of 1:3, indicating again a disproportionation of S0. The observed microbial disproportionation of S0 only proceeds significantly in the presence of sulfide-scavenging agents such as iron and manganese compounds. The population density of bacteria capable of S0 disproportionation in the presence of FeOOH or MnO2 was high, > 104 cm-3 in coastal sediments. The metabolism offers an explanation for recent observations of anaerobic sulfide oxidation to sulfate in anoxic sediments. PMID:16348835

  19. Characterization of biological iron sulfide composites and its application in the treatment of cadmium-contaminated wastewater.

    PubMed

    Yang, Yang; Xie, Yifei; Li, Xudong

    2015-03-01

    A strain of sulfate reducing bacteria, which could generate biological iron sulfide composites, was applied for Cd (II) removal from wastewater. The influence of biological iron sulfide composites dosage, initial pH and temperature on the rate of Cd (II) removal from wastewater by biological iron sulfide composites were investigated. The microscopic morphological characteristics and elemental composition changes of the biological iron sulfide before and after treatment was compared, using scanning electron microscopy and energy-dispersive spectrometry, then the mechanism of Cd (II) removal was explored. The results showed that Cd (II) reduction rate increased with increase in dosage of biological iron sulfide composites and initial temperature. At 25 degrees C, pH 4.0, with dosage of sulfide and cadmium ions molar equal to 99.93% Cd (II) was removed from cadmium wastewater (100 mg l(-1)), and the residual concentration of cadmium reached Chinese Integrated Wastewater Discharge Standard (GB8978-1996). The present study revealed that bio- precipitation of FeS, the main component of biological iron sulfide composites, played leading role in the process of Cd (II) reduction. Therefore, it is prospective to apply biological iron sulfide composites in the emergency treatment of cadmium-contaminated wastewater. PMID:25895261

  20. Adsorption of copper, cadmium, lead and zinc onto a synthetic manganese oxide.

    PubMed

    Della Puppa, Loïc; Komárek, Michael; Bordas, François; Bollinger, Jean-Claude; Joussein, Emmanuel

    2013-06-01

    Due to its simple and inexpensive synthesis, a new amorphous hydrous manganese oxide (AMO) has been studied as a possible chemical stabilizing agent for soils contaminated with metals. Preliminary experiments evaluating the stability of AMO in pure water have reported only minor dissolution (5.70% and 0.24% depending on the w/v ratio). Sorption kinetics have shown fast metal adsorption, especially for Pb. The sorption capacities of AMO for Cu, Cd, Pb, and Zn have been described and compared with synthetic birnessite for pH 4 and 5.5. Both oxides show similar sorption capacities at pH 4 despite the fact that birnessite characteristics (pH of zero point charge, specific surface area and cation exchange capacity) are more favorable for metal sorption. Moreover, the pH adsorption-edges show that the AMO is more pH-dependent than birnessite. PMID:23566588

  1. Diffusion zone between high-chromium cast iron and high-manganese steel during electric-slag facing

    SciTech Connect

    Ponomarenko, V.P.; Shvartser, A.Y.; Stroganova, G.V.

    1986-05-01

    The authors investigate extending the service lives of components by the method of electric-slag facing of working surfaces. Steel 45 was used in the annealed state. Electric-slag remelting was the method used to determine the bending strength. Metallographic examinations were conducted under an MIM-8m microscope, while x-ray analysis of the built-up and base metals were performed on a DRON-2 diffractometer. BAsic alloying elements, chromium and manganese were studied on a ''Cameca MS-46'' microanalyzer. During the electri-slag facing of a high-chromium cast iron containing 8% of Mn on high-manganese steel 11OG13L diffusion equalization of the manganese content occurs in the fusion zone. Diffusion displacement of carbon, chromium, and manganese from high-chromium cast iron into the high-manganese steel during electric-slag facing gies rise to a smooth change in the structure of the metal in the fusion zone, and to increased strength of the joint between the unlike materials investigated.

  2. Novel processing of iron-manganese alloy-based biomaterials by inkjet 3-D printing.

    PubMed

    Chou, Da-Tren; Wells, Derrick; Hong, Daeho; Lee, Boeun; Kuhn, Howard; Kumta, Prashant N

    2013-11-01

    The present work provides an assessment of 3-D printed iron-manganese biodegradable scaffolds as a bone scaffold material. Iron-based alloys have been investigated due to their high strength and ability to slowly corrode. Current fabrications of Fe-based materials generate raw material which must be machined into their desired form. By using inkjet 3-D printing, a technique which generates complex, customizable parts from powders mechanically milled Fe-30Mn (wt.%) powder was directly processed into scaffolds. The 3-D printed parts maintained an open porosity of 36.3% and formed a mixed phase alloy of martensitic ? and austenitic ? phases. Electrochemical corrosion tests showed the 3-D printed Fe-Mn to desirably corrode significantly more rapidly than pure iron. The scaffolds exhibited similar tensile mechanical properties to natural bone, which may reduce the risk of stress shielding. Cell viability testing of MC3T3-E1 pre-osteoblast cells seeded directly onto the Fe-Mn scaffolds using the live/dead assay and with cells cultured in the presence of the scaffolds' degradation products demonstrated good in vitro cytocompatibility compared to tissue culture plastic. Cell infiltration into the open pores of the 3-D printed scaffolds was also observed. Based on this preliminary study, we believe that 3-D printed Fe-Mn alloy is a promising material for craniofacial biomaterial applications, and represents an opportunity for other biodegradable metals to be fabricated using this unique method. PMID:23624222

  3. Acetyl transfer between manganese and iron complexes: Reaction of acetylpentacarbonylmanganese with dicarbonylcyclopentadienyliron(0)

    SciTech Connect

    Wang, P.; Atwood, J.D. [State Univ. of New York, Buffalo, NY (United States)

    1993-12-31

    Reactions of Mn(CO){sub 5}(C(O)Me) with CpFe(CO){sub 2}- results in CpFe(CO){sub 2}Me, Cp{sub 2}Fe{sub 2}(CO){sub 4} and Mn(CO){sub 5}- in less than five minutes at room temperature. Labeling the carbonyl of the acetyl puts the label only on a carbonyl of the CpFe(CO){sub 2}Me. Thus the acetyl is transferred from the manganese to the iron as a group, before CO dissociation leads to the methyl product. CO dissociation from CpFe(CO){sub 2}(C(O)Me) does not occur under the experimental conditions. A scheme is suggested to accommodate these observations. 13 refs., 1 tab.

  4. Synthetic, Biochemical, Antifertility and Antiinflammatory Aspects of Manganese and Iron Complexes

    PubMed Central

    Chaudhary, Ashu; Phor, Anita; Sharma, Sanjay; Gajraj, Anita

    2002-01-01

    Manganese(II) and iron(II) macrocyclic complexes of polyamide groups have been synthesized by the template codensation of diamines (2,6 diaminopyridine, 1,2 phenylenediamine and 1,3 phenylenediame) and triamine (diethylenetriamine) with phthalic acid in 1:2:2 molar ratios. On the basis of elemental analysis, IR, electronic, magnetic moment, Mössbauer, mass and X-ray spectral studies, octahedral structure has been assigned to [ M ( N 4 mac n ) Cl 2 ] (M = Mn(II) and Fe(II), n = 1 to 4) complexes. The complexes have been screened in vitro against a number of fungi and bacteria to assess their growth inhibiting potential. An attempt has been made to correlate the structural aspects of the compounds with their antiinflammatory and antifertility activities. PMID:18475430

  5. Manganese exposure among smelting workers: Relationship between blood manganese–iron ratio and early onset neurobehavioral alterations

    PubMed Central

    Cowan, Dallas M.; Zheng, Wei; Zou, Yan; Shi, Xiujuan; Chen, Jian; Rosenthal, Frank S.; Fan, Qiyuan

    2014-01-01

    A biomarker for detection of early onset neurobehavioral alterations in manganism remains unknown. The purpose of this study was to use a neurobehavioral test battery to identify subtle changes in Mn-induced motor and memory dysfunction and to relate the quantifiable neurological dysfunction to an established Mn-exposure index such as blood manganese–iron ratio (MIR). A total of 323 subjects were recruited to control (n = 106), low-exposure (122), and high-exposure (95) groups. The test battery consisted of standard testing procedures including the nine-hole and groove-type steadiness tester, Benton visual retention test, and Purdue pegboard coordination test. No significant health problems or clinically diagnosed neurological dysfunctions were observed. Benton test did not reveal any abnormal memory deficits among Mn-exposed smelters, nor did the groove and nine-hole tests detect any abnormality in dynamic and static steadiness in tested subjects. Purdue pegboard test showed a remarkable age-related decline in fine movement coordination among all study participants regardless of the Mn-exposure condition. Mn exposure significantly exacerbated this age-related deterioration. Statistical modeling revealed that the plasma and erythrocyte MIR (i.e., pMIR and eMIR, respectively) were associated with Purdue pegboard scores. Among all subjects whose MIR were above the cut-off value (COV), pMIR was significantly correlated with pegboard scores (r = ?0.261, p = 0.002), whereas for those subjects over the age of 40, the eMIR, but not pMIR, was associated with declined pegboard performance (r = ?0.219, p = 0.069). When both factors were taken into account (i.e., age > 40 and MIR > the COV), only pMIR was inversely associated with pegboard scores. Combining their usefulness in Mn-exposure assessment, we recommend that the blood Mn–Fe ratio may serve as a reasonable biomarker not only for assessment of Mn exposure but also for health risk assessment. PMID:19963104

  6. Biogeochemistry of the coupled manganese-iron-sulfur cycles of intertidal surface sediments

    NASA Astrophysics Data System (ADS)

    Bosselmann, K.; Boettcher, M. E.; Billerbeck, M.; Walpersdorf, E.; Debeer, D.; Brumsack, H.-J.; Huettel, M.; Joergensen, B. B.

    2003-04-01

    The biogeochemistry of the coupled iron-manganese-sulfur-carbon cycles was studied in temperate intertidal surface sediments of the German Wadden Sea (North Sea). Coastal sampling sites include sand, mixed and mud flats with different organic matter and metal contents and permeability reflecting different hydrodynamic regimes. The field study focusses on the influence of temperature, organic matter load, and sediment types on the dynamics of biogeochemical reactions on different time scales (season, day-night, tidal cycles). One of the main interests was related to the cycling of metals (Mn, Fe) in relation to the activity of sulfate-reducing bacteria. Pore water profiles were investigated by sediment sectioning and high resolution gel sampling techniques. Microbial sulfate reduction rates were measured using radiolabeled sulfate with the whole core incubation technique and the spatial distribution of bacterial activity was visualised by using "2D-photoemulsion-monitoring technique". The biogeochemical sulfur cycle was additionally characterised by the stable isotope ratios (S,O) of different sulfur species (e.g., SO_4, AVS, pyrite). Element transfers (metals, nutrients) across the sediment-water interface were additionally quantified by the application of benthic flux chambers. Microbial sulfate reduction was generally highest in the suboxic zone of the surface sediments indicating its potential importance for the mobilization of iron and manganese. In organic matter poor permeable sediments tidal effects additionally influence the spatial and temporal distribution of dissolved redox-sensitive metals. In organic matter-rich silty and muddy sediments, temperature controlled the microbial sulfate reduction rates. Depth-integrated sulfate reduction rates in sandy sediments were much lower and controlled by both temperature and organic matter. Formation of anoxic sediment surfaces due to local enhanced organic matter load (so-called "black spots") may create windows of an increase flux of metals, nutrients and hydrogen sulfide. Acknowledgements: The study was supported by German Science Foundation within the DFG-research group "BioGeoChemistry of the Waddensea" and Max Planck Society.

  7. Iron interactions and other biological reactions mediating the physiological and toxic actions of manganese.

    PubMed

    Roth, Jerome A; Garrick, Michael D

    2003-07-01

    Chronic exposure to the divalent heavy metals, such as iron, lead, manganese (Mn), and chromium, has been linked to the development of severe, often irreversible neurological disorders and increased vulnerability to developing Parkinson's disease. Although the mechanisms by which these metals elicit or facilitate neuronal cell death are not well defined, neurotoxicity is limited by the extent to which they are transported across the blood-brain barrier and their subsequent uptake within targeted neurons. Once inside the neuron, these heavy metals provoke a series of biochemical and molecular events leading to cell death induced by either apoptosis and/or necrosis. The toxicological properties of Mn have been studied extensively in recent years because of the potential health risk created by increased atmospheric levels owing to the impending use of the gas additive methylcyclopentadienyl manganese tricarbonyl. Individuals exposed to high environmental levels of Mn, which include miners, welders, and those living near ferroalloy processing plants, display a syndrome known as manganism, best characterized by debilitating symptoms resembling those of Parkinson's disease. Mn disposition in vivo is influenced by dietary iron intake and stores within the body since the two metals compete for the same binding protein in serum (transferrin) and subsequent transport systems (divalent metal transporter, DMT1). There appear to be two distinct carrier-mediated transport systems for Mn and ferrous ion: a transferrin-dependent and a transferrin-independent pathway, both of which utilize DMT1 as the transport protein. Accordingly, this commentary focuses on the biochemical and molecular processes responsible for the cytotoxic actions of Mn and the role that cellular transport plays in mediating the physiological as well as the toxicological actions of this metal. PMID:12818360

  8. Metallation and mismetallation of iron and manganese proteins in vitro and in vivo: the class I ribonucleotide reductases as a case study

    E-print Network

    Stubbe, JoAnne

    How cells ensure correct metallation of a given protein and whether a degree of promiscuity in metal binding has evolved are largely unanswered questions. In a classic case, iron- and manganese-dependent superoxide dismutases ...

  9. Spectroscopic Studies of the Iron and Manganese Reconstituted Tyrosyl Radical in Bacillus Cereus Ribonucleotide Reductase R2 Protein

    PubMed Central

    Tomter, Ane B.; Zoppellaro, Giorgio; Bell, Caleb B.; Barra, Anne-Laure; Andersen, Niels H.; Solomon, Edward I.; Andersson, K. Kristoffer

    2012-01-01

    Ribonucleotide reductase (RNR) catalyzes the rate limiting step in DNA synthesis where ribonucleotides are reduced to the corresponding deoxyribonucleotides. Class Ib RNRs consist of two homodimeric subunits: R1E, which houses the active site; and R2F, which contains a metallo cofactor and a tyrosyl radical that initiates the ribonucleotide reduction reaction. We studied the R2F subunit of B. cereus reconstituted with iron or alternatively with manganese ions, then subsequently reacted with molecular oxygen to generate two tyrosyl-radicals. The two similar X-band EPR spectra did not change significantly over 4 to 50 K. From the 285 GHz EPR spectrum of the iron form, a g1-value of 2.0090 for the tyrosyl radical was extracted. This g1-value is similar to that observed in class Ia E. coli R2 and class Ib R2Fs with iron-oxygen cluster, suggesting the absence of hydrogen bond to the phenoxyl group. This was confirmed by resonance Raman spectroscopy, where the stretching vibration associated to the radical (C-O, ?7a?=?1500 cm?1) was found to be insensitive to deuterium-oxide exchange. Additionally, the 18O-sensitive Fe-O-Fe symmetric stretching (483 cm?1) of the metallo-cofactor was also insensitive to deuterium-oxide exchange indicating no hydrogen bonding to the di-iron-oxygen cluster, and thus, different from mouse R2 with a hydrogen bonded cluster. The HF-EPR spectrum of the manganese reconstituted RNR R2F gave a g1-value of ?2.0094. The tyrosyl radical microwave power saturation behavior of the iron-oxygen cluster form was as observed in class Ia R2, with diamagnetic di-ferric cluster ground state, while the properties of the manganese reconstituted form indicated a magnetic ground state of the manganese-cluster. The recent activity measurements (Crona et al., (2011) J Biol Chem 286: 33053–33060) indicates that both the manganese and iron reconstituted RNR R2F could be functional. The manganese form might be very important, as it has 8 times higher activity. PMID:22432022

  10. The distribution of copper, manganese, zinc, and iron in antarctic waters and the relation of the concentrations of these metals to biological primary productivity 

    E-print Network

    Arhelger, Martin Edward

    1967-01-01

    THE DISTRIBUTION OF COPPER, MANGANESE, ZINC, AND IRON IN ANTARCTIC WATERS AND THE RELATION OF THE CONCENTRATIONS OF THESE METALS TO BIOLOGICAL PRIMARY PRODUCTIVITY A Thesis By MARTIN EDWARD ARHELGER Submitted to the Graduate College... of the Texas A& 1 University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August I967 Major Subj ect: CHEMICAL OCEANOGRAPHY THE DISTRIBUTION OF COPPER, MANGANESE, ZINC, AND IRON IN ANTARCTIC WATERS AND THE RELATION...

  11. Effects of iron and manganese in culture solution on their concentrations in roots and shoots of rice plants (Oryza sativa L.) grown under anaerobic conditions 

    E-print Network

    Bacha, Richard E

    1976-01-01

    EFFECTS OF IRON AND MANGANESE IN CULTURE SOLUTION ON THEIR CONCENTRATIONS IN ROOTS AND SHOOTS OF RICE PLANTS (~Or za sativa L. ) GROWN UNDER ANAEROBIC CONDITIONS A Thesis by RICHARD E. BACHA Submitted to the Graduate College of Texas ASM Un... i vers i ty in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE December 1976 Major Subject: Soil Science EFFECTS OF IRON AND MANGANESE IN CULTURE SOLUTION ON THEIR CONCENTRATIONS IN ROOTS AND SHOOTS OF RICE PLANTS...

  12. The Significance of Diagenesis versus Riverine Input in Contributing to the Sediment Geochemical Matrix of Iron and Manganese in an Intertidal Region

    Microsoft Academic Search

    C. A Thomas; L. I Bendell-Young

    1999-01-01

    Summer porewater and spring and summer surficial sediment samples were collected from 26 locations in the intertidal region of the Fraser River estuary. Porewaters were analysed for dissolved iron and manganese (as defined by species <0·2?m in diameter) to assess the contribution of diagenesis to concentrations of iron and manganese oxides at the sediment–water interface. Surficial sediment samples were geochemically

  13. Relationships between chemical forms of soil iron and manganese and their absorption by rice from 34 flooded Gulf Coast soils of Texas

    E-print Network

    Phillips, Douglas Patton

    1971-01-01

    submergence of 34 Gulf Coast soils . . . . . . . 10 Relationship between active (ammonium acetate- hydroquinone extractable) and water soluble manganese of 34 Texas Gulf Coast soils . . 11 Relationship between active (sodium hydrosulfite- EDTA extractable... determinations were made: (i) The concentrations of water soluble iron and manganese at weekly intervals from time of submergence; (ii) Reduction potential measurements at weekly intervals from time of submergence. (iii) The concentrations of iron...

  14. Mesoporous iron–manganese oxides for sulphur mustard and soman degradation

    SciTech Connect

    Štengl, Václav, E-mail: stengl@iic.cas.cz [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR, v.v.i., 250 68 ?ež (Czech Republic) [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR, v.v.i., 250 68 ?ež (Czech Republic); J.E. Purkyn? University in Ústí nad Labem, Faculty of Environment, 400 96 Ústí nad Labem (Czech Republic); Grygar, Tomáš Matys [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR, v.v.i., 250 68 ?ež (Czech Republic) [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR, v.v.i., 250 68 ?ež (Czech Republic); J.E. Purkyn? University in Ústí nad Labem, Faculty of Environment, 400 96 Ústí nad Labem (Czech Republic); Bludská, Jana [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR, v.v.i., 250 68 ?ež (Czech Republic)] [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR, v.v.i., 250 68 ?ež (Czech Republic); Opluštil, František; N?mec, Tomáš [Military Technical Institute of Protection Brno, Vesla?ská 230, 628 00 Brno (Czech Republic)] [Military Technical Institute of Protection Brno, Vesla?ská 230, 628 00 Brno (Czech Republic)

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ? New nanodispersive materials based on Fe and Mn oxides for degradations of warfare agents. ? The best activities for the degradation of sulphur mustard (97.9% in 64 min) and soman (97.9% in 64 min). ? One pot synthesis with friendly transformed to industrial conditions. -- Abstract: Substituted iron(III)–manganese(III, IV) oxides, ammonio-jarosite and birnessite, were prepared by a homogeneous hydrolysis of potassium permanganate and iron(III) sulphate with 2-chloroacetamide and urea, respectively. Synthesised oxides were characterised using Brunauer–Emmett–Teller (BET) surface area and Barrett–Joiner–Halenda porosity (BJH), X-ray diffraction (XRD), infrared spectroscopy (IR), Raman spectroscopy and scanning electron microscopy (SEM). The oxides were taken for an experimental evaluation of their reactivity against sulphur mustard (HD) and soman (GD). When ammonio-jarosite formation is suppressed by adding urea to the reaction mixture, the reaction products are mixtures of goethite, schwertmannite and ferrihydrite, and their degradation activity against soman considerably increases. The best activities for the degradation of sulphur mustard (97.9% in 64 min) and soman (97.9% in 64 min) were observed for FeMn{sub 7}5 with 32.6 wt.% Fe (36.8 wt.% Mn) and FeMn{sub 3}7U with 60.8 wt.% Fe (10.1 wt.% Mn) samples, respectively.

  15. Concentration of Copper, Iron, Zinc, Cadmium, Lead, and Nickel in Boar Semen and Relation to the Spermatozoa Quality

    Microsoft Academic Search

    Peter Massányi; Jozef Trandžík; Pavol Nad; Beáta Koréneková; Magdaléna Skalická; Robert Toman; Norbert Luká?; Peter Strapák; Marko Halo; Ján Tur?an

    2003-01-01

    The concentration of copper, iron, zinc, cadmium, lead, and nickel as well as its relation to spermatozoa quality was investigated. The semen samples were analyzed by atomic absorption spectrophotometry (AAS). The concentration of copper in boar semen was 1.64 ± 0.28 mg kg and of iron 16.14 ± 10.35 mg kg. The concentration of zinc in boar semen reached an average value of 171.74 ± 64.72 mg kg and the level of

  16. Bacterial removal in flow-through columns packed with iron-manganese bimetallic oxide-coated sand

    Microsoft Academic Search

    Seong-Jik Park; Chang-Gu Lee; Song-Bae Kim; Yoon-Young Chang; Jae-Kyu Yang

    2012-01-01

    The objective of this study was to investigate the performance of iron-manganese bimetallic oxide-coated sand (IMCS) in the removal of bacteria (Escherichia coli ATCC 11105) using small-scale (length = 20 cm, inner diameter = 2.5 cm) and 30-day long-term (length = 50 cm, inner diameter = 2.5 cm) column experiments. Results indicated that the bacterial removal capacity of IMCS (qeq =

  17. Evaluation of iron and manganese-coated pumice application for the removal of as(v) from aqueous solutions.

    PubMed

    Far, Leila Babaie; Souri, Bubak; Heidari, Masoumeh; Khoshnavazi, Roshan

    2012-01-01

    Arsenic contamination of water has been recognized as a serious environmental issue and there are reports on its epidemiological problems to human health. The objective of this study was to evaluate the performances of iron-coated pumice and manganese-coated pumice as the adsorbents for removing arsenate from aqueous solutions. The effect of various parameters such as adsorbent dose, contact time, pH and initial concentration on removal efficiency of arsenate were evaluated in batch mode. The data obtained from the kinetic studies were analyzed using kinetic models of pseudo-first-order and pseudo-second-order. In addition, two isotherm models of Freundlich and Langmuir were used to fit the experimental data. The results showed that the optimum dosage of iron-coated pumice and manganese-coated pumice for arsenate removal were 40 and 80 g/L whereas the adsorption process reached equilibrium after 80 and 100 min, respectively. The maximum removal efficiency of arsenate using the two adsorbents were both recorded in pH=3 as the removal efficiency gradually declined following every increase in pH values of the solution. Iron-coated pumice also showed to have high removal efficiency when the initial concentration of arsenate was high while the low concentration of arsenate was efficiently removed by manganese-coated pumice. Moreover, it was depicted that the adsorption kinetics by both adsorbents followed pseudo-second order equation and the uptake data of arsenate were well fitted with Langmuir isotherm model. Therefore, it could be concluded that iron and manganese-coated pumice could be considered as suitable adsorbents for arsenate removal from aqueous solutions. PMID:23369510

  18. Diagnostics of manganese-iron nodules in soddy-podzolic soils at different degrees of gleyzation from their magnetic properties

    Microsoft Academic Search

    V. F. Babanin; V. I. Nikolaev; D. E. Pukhov; A. M. Shipilin; O. A. Shirmina

    2007-01-01

    The composition and magnetic properties of manganese-iron nodules in soddy-podzolic soils at different degrees of hydromorphism\\u000a were studied. The data of chemical analysis, magnetic measurements, and X-ray diffraction analysis indicate that the nanoparticles\\u000a of magnetite act as a strongly magnetic phase in these nodules. The distribution of strongly magnetic nodules in soils and\\u000a the absence of correlation between the content

  19. Diagnostics of manganese-iron nodules in soddy-podzolic soils at different degrees of gleyzation from their magnetic properties

    Microsoft Academic Search

    V. F. Babanin; V. I. Nikolaev; D. E. Pukhov; A. M. Shipilin; O. A. Shirmina

    2007-01-01

    The composition and magnetic properties of manganese-iron nodules in soddy-podzolic soils at different degrees of hydromorphism were studied. The data of chemical analysis, magnetic measurements, and X-ray diffraction analysis indicate that the nanoparticles of magnetite act as a strongly magnetic phase in these nodules. The distribution of strongly magnetic nodules in soils and the absence of correlation between the content

  20. Zinc, lead and cadmium accumulation and tolerance in Typha latifolia as affected by iron plaque on the root surface

    Microsoft Academic Search

    Zhihong Ye; Alan J. M Baker; Ming-Hung Wong; Arthur J Willis

    1998-01-01

    The effects of iron plaque on the growth of Typha latifolia L. and its accumulation of zinc (Zn), lead (Pb) and cadmium (Cd) were investigated under field conditions and in nutrient solution cultures in the laboratory. In the field, Zn concentrations (but not Cd) on the root surface were positively related to Fe concentrations on the root surface. In the

  1. THE COMPARATIVE EXCLUSION OF ZINC AND IRON FROM RICE GRAIN IN RELATION TO RICE GRAIN CADMIUM: IMPLICATIONS FOR HUMAN HEALTH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice grain samples collected from within an isolated and geo-physically unique Zinc/Cadmium (Zn/Cd) co-contaminated area in Thailand suggests that the rice plant effectively controls grain Zn and Iron (Fe) uptake even though concurrent aqua regia digested soil Zn and Fe concentrations ranged from 25...

  2. Effect of lactose, copper and iron on manganese retention and tissue distribution in rats fed dextrose-casein diets.

    PubMed

    King, B D; Lassiter, J W; Neathery, M W; Miller, W J; Gentry, R P

    1980-03-01

    The effect of iron, lactose and copper on manganese retention was studied in rats fed two diets. Thirty-six male albino rats (75 to 100 g) were allotted to six groups of six rats each. Three groups received a purified manganese-free dextrose-casein diet, and three groups received the same purified diet with 17% lactose added at the expense of dextrose. One group fed each of the above diets received either a manganese-free mineral mixture, the mineral mixture with 5 ppm supplemental Cu or the same mineral mixture with Fe removed. After 7 days on the diets, each rat was given, by gavage, 10 muCi of 54Mn activity as 54MnCl2 in a sodium acetate buffer. On the third day after dosing, the rats were sacrificed and samples of liver, kidneys, semitendinosus muscle, spleen and tibia were taken for stable and radioactive manganese analysis. Lactose added to the purified diet depressed 54Mn retention in all tissues studied. Lactose addition also decreased specific activities of the livers and kidneys but tended to increase stable manganese values. Copper apparently had little direct effect on 54Mn retention but tended to reduce the effect of lactose on 54Mn retention. Omission of Fe greatly increased 54Mn retention values in all tissues studied with or without added lactose. Fe omission also significantly increased the specific activities and stable Mn values of livers and the specific activity of kidneys. The results indicate that low dietary Fe may be a contributing factor to the increased manganese retention observed in this study and a previous study. PMID:7364681

  3. Induction of superoxide dismutases in Escherichia coli by manganese and iron

    SciTech Connect

    Pugh, S.Y.R.; DiGuiseppi, J.L.; Fridovich, I.

    1984-10-01

    Growth of Escherichia coli B in simple media enriched with Mn(II) resulted in the elevation of the manganese-containing superoxide dismutase, whereas growth in such medium enriched with iron caused increased content of the iron-containing superoxide dismutase. Enrichment of the medium with Co(II), Cu(II), Mo(VI), Zn(II), or Ni(II) had no effect. The inductions of superoxide dismutase by Mn(II) or by Fe(II) were dioxygen dependent, but these metals did not affect the CN/sup -/-resistant respiration of E. coli B and did not influence the increase in the CN/sup -/-resistant respiration caused by paraquat. Mn(II) and paraquat acted synergistically in elevating the superoxide dismutase content, and Mn(II) reduced the growth inhibition imposed by paraquat. E. coli grown in the complex 3% Trypticase soy broth (BBL Microbiology Systems)-0.5% yeast extract-0.2% glucose medium contained more superoxide dismutase than did cells grown in the simple media and were less responsive to enrichment of the medium with Mn(II) or Fe(II). Nevertheless, in the presence of paraquat, induction of superoxide dismutase by these metals could be seen even in the Trypticase-yeast extract-glucose medium. On the basis of these observations, the authors propose that the apo-superoxide dismutases may act as autogenous repressors and that Mn(II) and Fe(II) increase the cell content of the corresponding enzymes by speeding the conversion of the apo- to the holoenzymes.

  4. Iron deficient and manganese supplemented diets alter metals and transporters in the developing rat brain.

    PubMed

    Garcia, Stephanie J; Gellein, Kristin; Syversen, Tore; Aschner, Michael

    2007-01-01

    Manganese (Mn) neurotoxicity in adults can result in psychological and neurological disturbances similar to Parkinson's disease, including extrapyramidal motor system defects and altered behaviors. Iron (Fe) deficiency is one of the most prevalent nutritional disorders in the world, affecting approximately 2 billion people, especially pregnant and lactating women, infants, toddlers, and adolescents. Fe deficiency can enhance brain Mn accumulation even in the absence of excess Mn in the environment or the diet. To assess the neurochemical interactions of dietary Fe deficiency and excess Mn during development, neonatal rats were exposed to either a control diet, a low-Fe diet (ID), or a low-Fe diet supplemented with Mn (IDMn) via maternal milk during the lactation period (postnatal days [PN] 4-21). In PN21 pups, both the ID and IDMn diets produced changes in blood parameters characteristic of Fe deficiency: decreased hemoglobin (Hb) and plasma Fe, increased plasma transferrin (Tf), and total iron binding capacity (TIBC). Treated ID and IDMn dams also had decreased Hb throughout lactation and ID dams had decreased plasma Fe and increased Tf and TIBC on PN21. Both ID and IDMn pups had decreased Fe and increased copper brain levels; in addition, IDMn pups also had increased brain levels of several other essential metals including Mn, chromium, zinc, cobalt, aluminum, molybdenum, and vanadium. Concurrent with altered concentrations of metals in the brain, transport proteins divalent metal transporter-1 and transferrin receptor were increased. No significant changes were determined for the neurotransmitters gamma aminobutyric acid and glutamate. The results of this study confirm that there is homeostatic relationship among several essential metals in the brain and not simply between Fe and Mn. PMID:17060373

  5. Speciation of dissolved iron(II) and manganese(II) in a groundwater pollution plume

    SciTech Connect

    Jensen, D.L.; Boddum, J.K.; Redemann, S.; Christensen, T.H. [Technical Univ. of Denmark, Lyngby (Denmark)] [Technical Univ. of Denmark, Lyngby (Denmark)

    1998-09-15

    Groundwater samples with high concentrations of Fe(II) and Mn(II), obtained from an anaerobic pollution plume, were speciated under anaerobic conditions in terms of colloidal (screen filtration and cross-flow ultrafiltration), complexed (ion-exchange resins), and free divalent species of Fe(II) and Mn(II). Most of the metal content in a nonfiltered sample passed through a 0.001 {micro}m membrane and was considered truly dissolved. Although free metal ions were the dominant species in the dissolved fraction, speciation modeling using MINTEQA2 suggested an average of 19% Fe(II) a/nd 20% Mn(II) were present as bicarbonate complexes, which are here operationally defined as labile. Organic complexes were not significant, although the groundwater contained up to 67 mg of C L{sup {minus}1}. Calculations with MINTEQA2 indicated that sample solutions representative of the truly dissolved fraction were strongly supersaturated with respect to siderite (FeCO{sub 3}) and moderately supersaturated with respect to rhodochrosite (MnCO{sub 3}). SEM-EDS (Scanning Electron Microscopy combined with Energy Dispersive X-ray Spectroscopy) analysis indicated that the colloidal fractions most likely consisted of clay type particles and iron sulfide precipitates. The amount of Mn(II) in the colloidal fractions was too low for determination by SEM-EDS. These results show that roughly 65% of the iron and manganese in anaerobic pollution plumes is present as free divalent ions and, according to the current thermodynamic database in MINTEQA2, the solutions are supersaturated with respect to carbonate.

  6. AurF from Streptomyces thioluteus and a possible new family of manganese/iron oxygenases.

    PubMed

    Krebs, Carsten; Matthews, Megan L; Jiang, Wei; Bollinger, J Martin

    2007-09-18

    We recently reported that the R2 subunit of class Ic ribonucleotide reductase from Chlamydia trachomatis contains a heterodinuclear Mn/Fe redox cofactor [Jiang, W., Yun, D., Saleh, L., Barr, E. W., Xing, G., Hoffart, L. M., Maslak, M.-A., Krebs, C., and Bollinger, J. M., Jr. (2007) Science 316, 1188-1191]. The N-oxygenase, AurF, from Streptomyces thioluteus catalyzes the six-electron oxidation of p-aminobenzoate to p-nitrobenzoate and contains the EX2HX60-180EX2H sequence motif previously used to identify proteins with non-heme diiron clusters. Two research groups independently obtained evidence for the presence of iron and manganese in preparations of AurF. The electron paramagnetic resonance (EPR) spectrum of purified, resting AurF presented in one of these studies is markedly similar to the spectrum of the MnIII/FeIII form of C. trachomatis R2. We propose that S. thioluteus AurF also may harbor a heterodinuclear Mn/Fe cofactor, which it may use to activate O2 for oxidation of the aryl amine to the nitro compound. Hypothetical proteins encoded in the genomes of several other bacteria have similar sequences and may also be members of this nascent family of oxygen-activating Mn/Fe proteins. PMID:17718517

  7. Early diagenetic processes generate iron and manganese oxide layers in the sediments of Lake Baikal, Siberia.

    PubMed

    Torres, Natascha T; Och, Lawrence M; Hauser, Peter C; Furrer, Gerhard; Brandl, Helmut; Vologina, Elena; Sturm, Michael; Bürgmann, Helmut; Müller, Beat

    2014-04-01

    Distinct layers of iron(III) and manganese(IV) (Fe/Mn) oxides are found buried within the reducing part of the sediments in Lake Baikal and cause considerable complexity and steep vertical gradients with respect to the redox sequence. For the on-site investigation of the responsible biogeochemical processes, we applied filter tube samplers for the extraction of sediment porewater combined with a portable capillary electrophoresis instrument for the analyses of inorganic cations and anions. On the basis of the new results, the sequence of diagenetic processes leading to the formation, transformation, and dissolution of the Fe/Mn layers was investigated. With two exemplary cores we demonstrate that the dissolution of particulate Fe and Mn is coupled to the anaerobic oxidation of CH? (AOM) either via the reduction of sulphate (SO?(2-)) and the subsequent generation of Fe(II) by S(-II) oxidation, or directly coupled to Fe reduction. Dissolved Fe(II) diffuses upwards to reduce particulate Mn(IV) thus forming a sharp mineral boundary. An alternative dissolution pathway is indicated by the occurrence of anaerobic nitrification of NH?(+) observed at locations with Mn(IV). Furthermore, the reasons and consequences of the non-steady-state sediment pattern and the resulting redox discontinuities are discussed and a suggestion for the burial of active Fe/Mn layers is presented. PMID:24619231

  8. Molecular-Level Processes Governing the Interaction of Contaminants with Iron and Manganese Oxides - Final Report

    SciTech Connect

    Brown Jr., G. E.; Chambers, S. A.

    1999-10-31

    Many of the inorganic and organic contaminants present in sediments at DOE sites can be altered or destroyed by reduction and oxidation (redox) reactions occurring at mineral surfaces. A fundamental understanding of such redox processes provided by molecular-level studies on structurally and compositionally well-defined mineral surfaces will lead to: (i) improved models of contaminant fate and transport in geochemical systems, and (ii) optimized manipulation of these processes for remediation purposes. To contribute to this understanding, we will study, both experimentally and theoretically, redox processes involving three important contaminants - chromate ion, carbon tetrachloride, and trichloroethene TCE, on the following iron and manganese oxides - hematite, magnetite, maghemite, and pyrolusite. These oxides and their hydroxylated analogs commonly occur as coatings on minerals or as interfaces in the subsurface environment. Single-crystal surfaces of these oxides will be synthesized in carefully controlled fashion by molecular beam epitaxy. These surfaces, as well as high surface are powdered samples of these oxides, will be used in spectroscopic and kinetic experiments in both aqueous and gas phases. Our goal is to identify products and to determine the kinetics and mechanisms of surface-catalyzed redox reaction of Cr(VI) and CR(III), and the reductive dechlorination of carbon tetrachloride and TCE. The combination of theory and experiment will provide the base information needed to scale from the molecular level to the microscopic grain level minerals.

  9. Geometric and Electronic Structures of Manganese-substituted Iron Superoxide Dismutase

    PubMed Central

    Jackson, Timothy A.; Gutman, Craig T.; Maliekal, James; Miller, Anne-Frances; Brunold, Thomas C.

    2013-01-01

    The active-site structures of the oxidized and reduced forms of manganese-substituted iron superoxide dismutase (Mn(Fe)SOD) are examined, for the first time, using a combination of spectroscopic and computational methods. On the basis of electronic absorption, circular dichrosim (CD), magnetic CD (MCD), and variable-temperature variable-field MCD data obtained for oxidized Mn(Fe)SOD, we propose that the active site of this species is virtually identical to that of wild-type manganese SOD (MnSOD), both containing a metal ion that resides in a trigonal bipyramidal ligand environment. This proposal is corroborated by quantum mechanical / molecular mechanical (QM/MM) computations performed on complete protein models of Mn(Fe)SOD in both its oxidized and reduced states and, for comparison, wild-type (WT) MnSOD. The major differences between the QM/MM optimized active sites of WT MnSOD and Mn(Fe)SOD are a smaller (His)N–Mn–N(His) equatorial angle and a longer (Gln146(69))NH?O(sol) H-bond distance in the metal-substituted protein. Importantly, these modest geometric differences are consistent with our spectroscopic data obtained for the oxidized proteins and high-field electron paramagnetic resonance spectra reported previously for reduced Mn(Fe)SOD and MnSOD. As Mn(Fe)SOD exhibits a reduction midpoint potential (Em) almost 700 mV higher than that of MnSOD, which has been shown to be sufficient for explaining the lack of SOD activity displayed by the metal-subtituted species (Vance, C. K.; Miller, A. F. Biochemistry 2001, 40, 13079–13087), Ems were computed for our experimentally validated QM/MM optimized models of Mn(Fe)SOD and MnSOD. These computations properly reproduce the experimental trend and reveal that the drastically elevated Em of the metal substituted protein stems from a larger separation between the second-sphere Gln residue and the coordinated solvent in Mn(Fe)SOD relative to MnSOD, which causes a weakening of the corresponding H-bond interaction in the oxidized state and alleviates steric crowding in the reduced state. PMID:23461587

  10. Chemiluminescent photon yields measured in the flame photometric detector on chromatographic peaks containing sulfur, phosphorus, manganese, ruthenium, iron or selenium

    NASA Astrophysics Data System (ADS)

    Aue, Walter A.; Singh, Hameraj

    2001-05-01

    Photon yields — the number of photons generated per analyte atom — are of obvious analytical and mechanistic importance in flame chemiluminescence. However, such numbers are unavailable for spectral detectors in gas chromatography (as well as for most conventional spectroscopic systems). In this study, photon yields have been determined for the chemiluminescence of several elements in the flame photometric detector (FPD). The number of photons generated per atom of FPD-active element was 2×10 -3 for sulfur (emitter S 2*, test compound thianaphthene), 3×10 -3 for phosphorus [HPO*, tris(pentafluorophenyl)phosphine], 8×10 -3 for manganese (Mn*, methylcyclopentadienyl manganese tricarbonyl), 3×10 -3 for ruthenium (emitter unknown, ruthenocene), 4×10 -5 for iron (Fe*, ferrocene) and 2×10 -4 for selenium (Se 2*, dimethylbenzselenazole). Total flows, maximum thermocouple temperatures, and visible flame volumes have also been estimated for each element under signal/noise-optimized conditions in order to provide a database for kinetic calculations.

  11. Cadmium, Copper, Iron, Lead, Manganese, and Zinc in Evaporated Milk, Infant Products, and Human Milk

    Microsoft Academic Search

    G. K. Murthy

    1971-01-01

    Infant formula foods, such as evaporated milk, modified milk, and formulas contain- ing lamb meat and soya flour, were col leered quarterly from the Cincinnati, Ohio, market. Human milk from 13 mothers residing in the Cincinnati area was col- lected during April and May 1968. They were analyzed for Cd, Cu, Fe, Pb, Mn, and Zn by atomic absorption speetro-

  12. Changes in Dietary Iron Exacerbate Regional Brain Manganese Accumulation as Determined by Magnetic Resonance Imaging

    PubMed Central

    Fitsanakis, Vanessa A.; Zhang, Na; Avison, Malcolm J.; Erikson, Keith M.; Gore, John C.; Aschner, Michael

    2011-01-01

    Manganese (Mn) is an essential metal required for normal homeostasis. Humans chronically exposed to high Mn levels, however, may exhibit psychomotor signs secondary to increased brain Mn. As Mn and iron (Fe) share several cellular membrane transporters, decreased Fe levels resulting from Fe deficiency or anemia lead to increased brain Mn deposition. Conversely, decreased Mn levels are associated with abnormal brain Fe accumulation. To reduce potential Mn toxicity resulting from brain Mn accumulation, we proposed that increased dietary Fe would attenuate brain Mn deposition. To test this hypothesis, three groups of Sprague-Dawley rats were injected weekly (14 weeks) with Mn (3 mg/kg) and fed normal Fe (TX), Fe-supplemented (FeS), or Fe-deficient (FeD) chow. Control (CN) rats received normal dietary Fe and saline injections. Using magnetic resonance imaging, rats were imaged biweekly for 14 weeks to qualitatively monitor brain Mn and Fe accumulation. Both FeS and FeD had greater brain Mn deposition than TX rats. By week 3, R1 values, which correlate with Mn deposition, were statistically significantly increased (p < 0.05) in brain stem, cerebellum, cortex, midbrain, and striatum compared with CN or TX animals. By week 14, R1 values for all brain regions in FeS and FeD animals were statistically significantly increased (p < 0.05). By the end of the study, similar results were obtained for R2 values, a marker of Fe accumulation. These data suggest that Fe supplementation does not effectively protect and may even exacerbate brain Mn accumulation in mammals subchronically exposed to Mn. PMID:21177776

  13. Single, binary, and multicomponent sorption of iron and manganese on lignite

    SciTech Connect

    Mohad, D.; Chander, S. [Penn State University, University Park, PA (United States). Dept. of Energy & Geoenvironmental Engineering

    2006-07-01

    Acid mine drainage (AMD) has long been a significant environmental problem resulting from the microbial oxidation of iron pyrite in the presence of water and air, affording an acidic solution that contains toxic metal ions. The main objective of this study was to remove metal ions (Fe(II), Fe(III), Mn(II), Zn(II)) from AMD using lignite, a low-cost adsorbent. The lignite sorbent was utilized for the sorption of ferrous, ferric, manganese, zinc, and calcium ions in aqueous solutions. Studies were performed at different pH to find optimum pH. Equilibrium isotherms were determined to assess the maximum adsorption capacity of lignite for different metal ions. Sorption capacities were compared in single, binary, ternary, and multicomponent systems. The sorption data are correlated with Freundlich and Langmuir isotherms in each system. Both Freundlich and Langmuir isotherms fit the data reasonably well in terms of regression coefficients. Sorption studies were also performed at different temperatures to obtain the thermodynamic parameters of the process. The maximum lignite adsorption capacities at 25{sup o}C were 34.22, 25.84, and 11.90 mg/g for Fe(II), Mn(II), and Fe(III), respectively. Adsorption of Fe{sup 2+} (24.70 mg/g at 10{sup o}C and 46.46 mg/g at 40{sup o}C) increased with increased temperature, while Mn{sup 2+} adsorption (28.11 mg/g at 10{sup o}C and 7.70 mg/g at 40{sup o}C) decreased with increased temperature.

  14. Stability Behavior and Thermodynamic States of Iron and Manganese in Sandy Soil Aquifer, Manukan Island, Malaysia

    SciTech Connect

    Lin, Chin Yik, E-mail: cy_lin_ars@hotmail.com [Universiti Malaysia Sabah, School of Science and Technology (Malaysia); Abdullah, Mohd. Harun [Universiti Malaysia Sabah, Water Research Unit, School of Science and Technology (Malaysia); Musta, Baba; Praveena, Sarva Mangala [Universiti Malaysia Sabah, School of Science and Technology (Malaysia); Aris, Ahmad Zaharin [Universiti Putra Malaysia, Faculty of Environmental Studies (Malaysia)

    2011-03-15

    A total of 20 soil samples were collected from 10 boreholes constructed in the low lying area, which included ancillary samples taken from the high elevation area. Redox processes were investigated in the soil as well as groundwater in the shallow groundwater aquifer of Manukan Island, Sabah, Malaysia. Groundwater samples (n = 10) from each boreholes were also collected in the low lying area to understand the concentrations and behaviors of Fe and Mn in the dissolved state. This study strives to obtain a general understanding of the stability behaviors on Fe and Mn at the upper unsaturated and the lower-saturated soil horizons in the low lying area of Manukan Island as these elements usually play a major role in the redox chemistry of the shallow groundwater. Thermodynamic calculations using PHREEQC showed that the groundwater samples in the study area are oversaturated with respect to goethite, hematite, Fe(OH){sub 3} and undersaturated with respect to manganite and pyrochroite. Low concentrations of Fe and Mn in the groundwater might be probably due to the lack of minerals of iron and manganese oxides, which exist in the sandy aquifer. In fact, high organic matters that present in the unsaturated horizon are believed to be responsible for the high Mn content in the soil. It was observed that the soil samples collected from high elevation area (BK) comprises considerable amount of Fe in both unsaturated (6675.87 mg/kg) and saturated horizons (31440.49 mg/kg) compared to the low Fe content in the low lying area. Based on the stability diagram, the groundwater composition lies within the stability field for Mn{sup 2+} and Fe{sup 2+} under suboxic condition and very close to the FeS/Fe{sup 2+} stability boundary. This study also shows that both pH and Eh values comprise a strong negative value thus suggesting that the redox potential is inversely dependent on the changes of pH.

  15. Basin-Scale Transport of Hydrothermal Iron, Manganese and Aluminum Across the Eastern South Pacific

    NASA Astrophysics Data System (ADS)

    Sedwick, P. N.; Resing, J. A.; Sohst, B. M.; Jenkins, W. J.; German, C. R.; Moffett, J. W.

    2014-12-01

    The U.S. GEOTRACES Eastern Pacific Zonal Transect cruise (GEOTRACES GP06) examined the water-column distribution of trace elements between Peru and Tahiti, crossing the southern East Pacific Rise (EPR) midway along the cruise track. Shipboard measurements made along this ocean section reveal the mid-depth lateral transport of hydrothermal dissolved iron (dFe), manganese (dMn) and aluminum (dAl) over a distance of more than 4,000 km, from the EPR westward into the deep South Pacific basin. Post-cruise measurements of the conservative hydrothermal tracer helium-3 indicate the loss of at least 85% of the hydrothermal dFe over a distance of ~80 km west from the ridge axis, presumably as a result of oxidation, scavenging and precipitation. Further west of the ridge axis, dFe and excess helium-3 (3Hexs) are linearly correlated (r2 = 0.99), showing a more than 4-fold conservative dilution of hydrothermal dFe over a distance of ~4000 km. This behavior may reflect the lateral transport of iron as relatively unreactive, colloidal oxyhydroxides; ongoing analyses of cruise samples by other groups will provide data to test this hypothesis. The loss of hydrothermal dMn relative to 3Hexs extends over a greater distance than for dFe, as far as ~250 km to the west of the ridge axis, beyond which dMn exhibits nearly conservative behavior. The hydrothermal dAl anomaly appears to extend over 3,000 km west of the EPR, and is not readily explained based on the known composition of ridge-axis vent fluids. The linear dFe versus 3Hexs relationship in the off-axis hydrothermal plume has a slope of 5.6 x 106 mol/mol, which falls roughly between values estimated for the western South Pacific and the South Atlantic basins. If we assume that our dFe and 3He data are generally representative of mid-ocean ridge hydrothermal emissions, then the estimated global hydrothermal 3He efflux of 530 mol/y yields an effective hydrothermal dFe input of 2.9 Gmol/y to the ocean interior.

  16. Arabidopsis Thaliana CARBOXYL-TERMINAL DOMAIN PHOSPHATASE-Like1 (CPL1) Mediates Responses to Iron Deficiency and Cadmium Toxicity

    E-print Network

    Aksoy, Emre

    2014-04-24

    ARABIDOPSIS THALIANA CARBOXYL-TERMINAL DOMAIN PHOSPHATASE- LIKE1 (CPL1) MEDIATES RESPONSES TO IRON DEFICIENCY AND CADMIUM TOXICITY A Dissertation by EMRE AKSOY Submitted to the Office of Graduate and Professional Studies of Texas... CTD C-TERMINAL DOMAIN vi CPL1 CTD PHOSPHATASE-LIKE1 LUC luciferase GUS ?-glucuronidase GFP Green Fluorescent Protein ABA abscisic acid ICP-MS inductively coupled plasma–mass spectrometry vii TABLE OF CONTENTS Page...

  17. Effect of Cadmium and Iron on Rice (Oryza Sativa L.) Plant in Chelator-Buffered Nutrient Solution

    Microsoft Academic Search

    Tapan Adhikari; Elisha Tel-Or; Yael Libal; Moshe Shenker

    2006-01-01

    To better understand the mechanisms responsible for differences in uptake and distribution of cadmium (Cd), nutrient-solution experiments were conducted with different varieties of rice (Oryza sativa), ‘Khitish’ and ‘CNRH3’. The plants were grown in a complete nutrient solution with different levels of pCd (-log free Cd activity) and pFe [-log free iron (Fe) activity]. The required concentrations of chelating agent

  18. Effects of iron and manganese in culture solution on their concentrations in roots and shoots of rice plants (Oryza sativa L.) grown under anaerobic conditions

    E-print Network

    Bacha, Richard E

    1976-01-01

    . Hossner The objectives of this investigation were to determine the relationships between iron and manganese in solution and in the plant, and to study the composition of coatings formed on the root epidermis of rice plants. Rice was transplanted... = 0. 81 ) and Nn 1n solution (r = 0. 80**). Both Fe and Mn prec1pitated on the root epidermis. Iron prec1pitated at all levels of Fe added. Manganese was only found in the coatings when at least 50 ppm Nn were appl1ed in the sand culture. Good...

  19. Effects of sulfur, zinc, iron, copper, manganese, and boron applications on sunflower yield and plant nutrient concentration

    SciTech Connect

    Hilton, B.R.; Zubriski, J.C.

    1985-01-01

    Sulfur, zinc, iron, copper, manganese, and boron application did not affect the seed yield or oil percentage of sunflower (Helianthus annuus L.) on both dryland and irrigated soils in North Dakota in 1981. Field averages indicated significant Zn, Mn, and B uptake by sunflower at the 12-leaf stage as a result of fertilization with these elements. Increased Zn uptake was also observed in the uppermost mature leaf at anthesis from zinc fertilization. Although sunflower yield from boron fertilization was not significantly different from the check, a trend was observed in which boron fertilization seemed to decrease sunflower yield. Sunflower yields from the boron treatment were the lowest out of seven treatments in three out of four fields. Also, sunflower yield from the boron treatment was significantly lower than both iron and sulfur treatments when all fields were combined.

  20. Effect of excessive dietary fluoride on nutrient digestibility and retention of iron, copper, zinc, and manganese in growing pigs.

    PubMed

    Tao, X; Xu, Z R; Wang, Y Z

    2005-11-01

    Ninety-six crossbred growing pigs were used to evaluate the effects of fluoride levels on growth performance, nutrient digestibility, and the retention of minerals in tissues. Four dietary treatments were formulated by supplementing fluorine (as NaF) to a corn-soybean basal diet (39.75 mg/kg F) to provide the following added fluorine levels: 0, 50, 100, and 150 mg/kg fluorine. The results showed pigs of the 100 and 150 mg/kg fluorine-added groups had decreased average daily gain (ADG) and increased feed gain ratio (F/G) compared to the control (p < 0.05). Apparent digestibility of protein and calcium in 100 and 150 mg/kg fluorine-treated groups was significantly lower than that of the control (p < 0.05). On the other hand, iron, copper, zinc, and manganese levels in most tissues of the 100 and 150 mg/kg fluorine groups were markedly changed compared to the control (p < 0.05). However, growth performance, nutrient digestibility, and mineral concentrations in all tissues of pigs were not significantly affected by the addition of 50 mg/kg fluorine (p > 0.05). Thus, this study suggested that excess fluoride levels could decrease growth performance and change the retention of iron, copper, zinc, and manganese in pigs. PMID:16217139

  1. Two-dimensional and fine structure in the concentrations of iron and manganese in sediment pore-waters

    SciTech Connect

    Shuttleworth, S.M.; Davison, W.; Hamilton-Taylor, J.

    1999-12-01

    The technique of diffusive equilibration in thin films (DET) was used to measure sediment pore-water concentrations of dissolved iron and manganese at high-spatial resolution (1 mm). Measurements in a laboratory microcosm of homogeneously mixed sediment gave reproducible concentration-depth profiles with no fine scale features. By contrast, measurements in undisturbed surface sediments showed fine structure that was only occasionally reproduced in profiles from several replicate field deployments. Although redox-related features in the profiles, indicative of processes traditionally considered to occur with lateral uniformity, were generally present, the details observed in the replicate deployments were different. DET was modified to allow horizontal as well as vertical measurement of pore-water solutes. The resulting 2D images of the distribution of iron and manganese concentration in pore-waters showed systematic vertical and horizontal structure. The individual component vertical profiles of the 2D measurement were only 3 mm apart and yet they were sometimes quite different from one another. These findings suggest that (1) microniches play a major role in metal remobilization, (2) results from single vertical profiles may not be representative, and (3) caution should be exercised when estimating exchange fluxes from vertical concentration gradients.

  2. Catalytic Convergence of Manganese and Iron Lipoxygenases by Replacement of a Single Amino Acid*

    PubMed Central

    Wennman, Anneli; Jernerén, Fredrik; Hamberg, Mats; Oliw, Ernst H.

    2012-01-01

    Lipoxygenases (LOXs) contain a hydrophobic substrate channel with the conserved Gly/Ala determinant of regio- and stereospecificity and a conserved Leu residue near the catalytic non-heme iron. Our goal was to study the importance of this region (Gly332, Leu336, and Phe337) of a lipoxygenase with catalytic manganese (13R-MnLOX). Recombinant 13R-MnLOX oxidizes 18:2n-6 and 18:3n-3 to 13R-, 11(S or R)-, and 9S-hydroperoxy metabolites (?80–85, 15–20, and 2–3%, respectively) by suprafacial hydrogen abstraction and oxygenation. Replacement of Phe337 with Ile changed the stereochemistry of the 13-hydroperoxy metabolites of 18:2n-6 and 18:3n-3 (from ?100% R to 69–74% S) with little effect on regiospecificity. The abstraction of the pro-S hydrogen of 18:2n-6 was retained, suggesting antarafacial hydrogen abstraction and oxygenation. Replacement of Leu336 with smaller hydrophobic residues (Val, Ala, and Gly) shifted the oxygenation from C-13 toward C-9 with formation of 9S- and 9R-hydroperoxy metabolites of 18:2n-6 and 18:3n-3. Replacement of Gly332 and Leu336 with larger hydrophobic residues (G332A and L336F) selectively augmented dehydration of 13R-hydroperoxyoctadeca-9Z,11E,15Z-trienoic acid and increased the oxidation at C-13 of 18:1n-6. We conclude that hydrophobic replacements of Leu336 can modify the hydroperoxide configurations at C-9 with little effect on the R configuration at C-13 of the 18:2n-6 and 18:3n-3 metabolites. Replacement of Phe337 with Ile changed the stereospecific oxidation of 18:2n-6 and 18:3n-3 with formation of 13S-hydroperoxides by hydrogen abstraction and oxygenation in analogy with soybean LOX-1. PMID:22822060

  3. Insights into the iron-ome and manganese-ome of ?mtm1 Saccharomyces cerevisiae Mitochondria

    PubMed Central

    Park, Jinkyu; McCormick, Sean P.; Chakrabarti, Mrinmoy

    2013-01-01

    Biophysical spectroscopies and LC-ICP-MS were used to evaluate the iron-ome and manganese-ome of mitochondria from ?mtm1 yeast cells. Deleting the mitochondrial carrier gene MTM1 causes Fe to accumulate in mitochondria and Mn superoxide dismutase (SOD2) activity to decline. One explanation for this is that some accumulated Fe misincorporates into apo-Sod2p. Mössbauer spectroscopy revealed that most of the accumulated Fe was FeIII nanoparticles which are unlikely to misincorporate into apo-Sod2p. Under anaerobic conditions, Fe did not accumulate yet SOD2 activity remained low, suggesting that the two phenomena are independent. Mn concentrations were two-fold higher in ?mtm1 mitochondria than in WT mitochondria. Soluble extracts from such samples were subjected to size-exclusion LC and fractions were analyzed with an on-line ICP-MS. Two major Mn peaks were observed, one due to MnSod2p and the other to a Mn species with a mass of 2–3 kDa (called Mn2–3). Mn2–3 may deliver Mn into apo-Sod2p. Most Mn in WT mitochondria was associated with MnSod2p, whereas most Mn in ?mtm1 mitochondria was associated with Mn2–3. The [Mn2–3] increased in cells grown on high MnCl2 while the MnSod2p concentration remained unchanged. Corresponding Fe traces showed numerous peaks, including a complex of ~ 3 kDa which may be the form of Fe that misincorporates, and an Fe peak with the molecular mass of Sod2p that may correspond to FeSod2p. The intensity of this peak suggests that deleting MTM1 probably diminishes SOD2 activity by some means other than Fe misincorporation. A portion of Sod2p in ?mtm1 mitochondria might be unfolded or immature. Mtm1p may import a species required for apo-Sod2p maturation, activity or stability. PMID:23598994

  4. Iron, copper, and manganese complexes with in vitro superoxide dismutase and/or catalase activities that keep Saccharomyces cerevisiae cells alive under severe oxidative stress.

    PubMed

    Ribeiro, Thales P; Fernandes, Christiane; Melo, Karen V; Ferreira, Sarah S; Lessa, Josane A; Franco, Roberto W A; Schenk, Gerhard; Pereira, Marcos D; Horn, Adolfo

    2015-03-01

    Due to their aerobic lifestyle, eukaryotic organisms have evolved different strategies to overcome oxidative stress. The recruitment of some specific metalloenzymes such as superoxide dismutases (SODs) and catalases (CATs) is of great importance for eliminating harmful reactive oxygen species (hydrogen peroxide and superoxide anion). Using the ligand HPClNOL {1-[bis(pyridin-2-ylmethyl)amino]-3-chloropropan-2-ol}, we have synthesized three coordination compounds containing iron(III), copper(II), and manganese(II) ions, which are also present in the active site of the above-noted metalloenzymes. These compounds were evaluated as SOD and CAT mimetics. The manganese and iron compounds showed both SOD and CAT activities, while copper showed only SOD activity. The copper and manganese in vitro SOD activities are very similar (IC50~0.4 ?mol dm(-3)) and about 70-fold higher than those of iron. The manganese compound showed CAT activity higher than that of the iron species. Analyzing their capacity to protect Saccharomyces cerevisiae cells against oxidative stress (H2O2 and the O2(•-) radical), we observed that all compounds act as antioxidants, increasing the resistance of yeast cells mainly due to a reduction of lipid oxidation. Especially for the iron compound, the data indicate complete protection when wild-type cells were exposed to H2O2 or O2(•-) species. Interestingly, these compounds also compensate for both superoxide dismutase and catalase deficiencies; their antioxidant activity is metal ion dependent, in the order iron(III)>copper(II)>manganese(II). The protection mechanism employed by the complexes proved to be independent of the activation of transcription factors (such as Yap1, Hsf1, Msn2/Msn4) and protein synthesis. There is no direct relation between the in vitro and the in vivo antioxidant activities. PMID:25511255

  5. Electronic structure of the dioxygen to transition metal bond: generalized molecular orbital calculations on models of manganese, iron, and cobalt porphyrins 

    E-print Network

    Newton, James Edward

    1982-01-01

    ELECTRONIC STRUCTURE OF THE DIOXYGEN TO TRANSITION METAL BOND: GENERALIZED MOLECULAR ORBITAL CALCULATIONS ON MODELS OF MANGANESE, IRON, AND COBALT PORPHYRINS A Thesis by JAMES EDWARD NEWTON Submitted to the Graduate College of Texas ASM..., IRON, AND COBALT PORPHYRINS A Thesis by JAMES EDWARD NEWTON Approved as to style and content by: (Chairman of Committee) (Member) mbe ember) (Head of part ent) May 1982 ABSTRACT Electronic Structure of the Dioxygen to Transition Metal Bond...

  6. The intake and excretion of lead and cadmium by the elderly.

    PubMed

    Bunker, V W; Lawson, M S; Delves, H T; Clayton, B E

    1984-05-01

    Metabolic balance for lead and cadmium were carried out in 23 healthy elderly people aged 69.7 to 85.5 yr while living in their own homes and eating self-selected diets. Mean intakes of lead and cadmium were 54.6 and 8.6 micrograms/day, with mean retentions of -8.7 and -1.7 micrograms/day, respectively. Daily dietary lead correlated (p less than 0.05) with the intake of energy, nitrogen, calcium, iron, and zinc but not with manganese or copper. Dietary intake of cadmium correlated (p less than 0.05) only with that of zinc and manganese. There was a highly significant (p less than 0.001) inverse correlation between the percentage cadmium absorbed and body iron stores measured as serum iron, percentage iron saturation, and ferritin. Mean whole blood concentrations were 138 micrograms/l for lead and 0.79 microgram/l for cadmium. The negative balances observed in these elderly people were very different from the positive balances found in a previous similar study in children. PMID:6711483

  7. A Green Analytical Method Using Ultrasound in Sample Preparation for the Flow Injection Determination of Iron, Manganese, and Zinc in Soluble Solid Samples by Flame Atomic Absorption Spectrometry

    PubMed Central

    Yebra, M. Carmen

    2012-01-01

    A simple and rapid analytical method was developed for the determination of iron, manganese, and zinc in soluble solid samples. The method is based on continuous ultrasonic water dissolution of the sample (5–30?mg) at room temperature followed by flow injection flame atomic absorption spectrometric determination. A good precision of the whole procedure (1.2–4.6%) and a sample throughput of ca. 25 samples h–1 were obtained. The proposed green analytical method has been successfully applied for the determination of iron, manganese, and zinc in soluble solid food samples (soluble cocoa and soluble coffee) and pharmaceutical preparations (multivitamin tablets). The ranges of concentrations found were 21.4–25.61??g?g?1 for iron, 5.74–18.30??g?g?1 for manganese, and 33.27–57.90??g?g?1 for zinc in soluble solid food samples and 3.75–9.90??g?g?1 for iron, 0.47–5.05??g?g?1 for manganese, and 1.55–15.12??g?g?1 for zinc in multivitamin tablets. The accuracy of the proposed method was established by a comparison with the conventional wet acid digestion method using a paired t-test, indicating the absence of systematic errors. PMID:22567553

  8. Biosynthesis and isomerization of 11-hydroperoxylinoleates by manganese- and iron-dependent lipoxygenases

    Microsoft Academic Search

    Ernst H. Oliw; Mirela Cristea; Mats Hamberg

    2004-01-01

    Manganese lipoxygenase (Mn-LO) oxygenates linoleic acid (LA) to a mixture of the hydroperoxides—11(S)-hydroperoxy-9Z,12Z-octadecadienoic acid [11(S)-HPODE] and 13(R)-hydroperoxy-9Z,11E-octadecadienoic acid [13(R)-HPODE]- and also catalyzes the conversion of 11(S)-HPODE to 13(R)-HPODE via oxygen-centered (LOO•) and carbon-centered (L•) radicals [Hamberg, M., Su, C., and Oliw, E. (1998) Manganese Lipoxygenase.\\u000a Discovery of a Bis-allylic Hydroperoxide as Product and Intermediate in a Lipoxygenase Reaction, J. Biol.

  9. Studies on the role of iron in the reversal of zinc, cadmium, vanadium, nickel, and cobalt toxicities in boiler pullets

    SciTech Connect

    Blalock, T.L.

    1986-01-01

    Excess dietary iron reduced the toxicity of cadmium (Cd), cobalt (Co), nickel (Ni) and vanadium (V) in chicks. In order to gain further insight into this phenomenon, the toxicity of these elements was examined under conditions of dietary iron deficiency, ca. 10 ppm, and excess, ca. 1010 ppm. Graded levels of Cd, Co, Ni, V and also of zinc (Zn) were added to achieve toxicities of these heavy metals. In every case the iron-supplemented chicks were less susceptible to the every case the iron-supplemented chicks were less susceptible to the toxicities of these elements than were those chicks receiving the iron-deficient diet. The results of these studies revealed that Fe alters the metabolism of Zn, Cd, V, Ni and Co in livers and kidneys of chicks. The data further show that Zn, Cd, and Co alter Fe metabolism in chick livers and kidneys. Additionally, hemoglobin concentration was altered by Zn, Cd, and V, as well as Fe, in chicks. The locus of these interactions was more clearly defined using the radioactive tracers /sup 109/Cd, /sup 60/Co, /sup 63/Ni, /sup 48/V, and /sup 65/Zn. Iron deficiency increased absorption of Co and Ni, reduced liver retention of Cd, and Zn without affecting absorption and increased blood and liver levels of V, possibly as a result of decreased bone uptake. The alteration of liver metabolism of Cd and Zn in iron deficiency was investigated using column chromatography and atomic absorption spectrophotometry. Adequate dietary iron appears to act synergistically with Cd and Zn to induce metallothionein in the liver. Increased dietary Fe was observed to result in an increased liver influx of Zn and Cd. It is possible that iron acts in this manner to induce metallothionein synthesis.

  10. Iron and copper accumulation in the brain of coxsackievirus-infected mice exposed to cadmium

    SciTech Connect

    Ilbaeck, N.-G. [Section of Infectious Diseases, Department of Medical Sciences, Uppsala University Hospital, S-751 85 Uppsala (Sweden) and Toxicology Division, National Food Administration, Uppsala (Sweden)]. E-mail: nils-gunnar.ilback@slv.se; Lindh, U. [Research in Metal Biology, Rudbeck Laboratory, Uppsala University, Uppsala (Sweden); Minqin, R. [Centre for Ion Beam Applications, Department of Physics, National University of Singapore (Singapore); Friman, G. [Section of Infectious Diseases, Department of Medical Sciences, Uppsala University Hospital, S-751 85 Uppsala (Sweden); Watt, F. [Centre for Ion Beam Applications, Department of Physics, National University of Singapore (Singapore)

    2006-11-15

    Cadmium (Cd) is a potentially toxic metal widely distributed in the environment and known to cause adverse health effects in humans. During coxsackievirus infection, the concentrations of essential and nonessential trace elements (e.g., iron (Fe), copper (Cu), and Cd) change in different target organs of the infection. Fe and Cu are recognized cofactors in host defence reactions, and Fe is known to be associated with certain pathological conditions of the brain. However, whether nonessential trace elements could influence the balance of essential trace elements in the brain is unknown. In this study the brain Fe, Cu, and Cd contents were measured through inductively coupled plasma mass spectrometry and their distributions determined by nuclear microscopy in the early phase (day 3) of coxsackievirus B3 (CB3) infection in nonexposed and in Cd-exposed female Balb/c mice. In CB3 infection the brain is a well-known target that has not been studied with regard to trace element balance. The brain concentration of Cu compared with that of noninfected control mice was increased by 9% (P<0.05) in infected mice not exposed to Cd and by 10% (not significant) in infected Cd-exposed mice. A similar response was seen for Fe, which in infected Cd-exposed mice, compared to noninfected control mice, tended to increase by 16%. Cu showed an even tissue distribution, whereas Fe was distributed in focal deposits. Changes in Cd concentration in the brain of infected mice were less consistent but evenly distributed. Further studies are needed to define whether the accumulation and distribution of trace elements in the brain have an impact on brain function.

  11. sup 210 Po and sup 210 Pb remobilization from lake sediments in relation to iron and manganese cycling

    SciTech Connect

    Benoit, G.; Hemond, H.F. (Massachusetts Institute of Technology, Cambridge (USA))

    1990-08-01

    The behavior of {sup 210}Po and {sup 210}Pb was studied in the water column of an oligotrophic, dimictic lake. Direct uptake of the radionuclides by sediments was negligible compared to removal on particles, and {sup 210}Pb scavenging was 4 times that of {sup 210}Po. Both nuclides were found to be significantly remobilized from sediments into the stratified, anoxic water column. Releases seem to be linked to the cycling of the transition metals, iron and possibly manganese. The distribution of both iron and {sup 210}Pb in stratified, anoxic waters can be modeled as constant release and rapid horizontal mixing/dilution; vertical turbulent transport had a negligible effect on element distributions. Upon contact with oxygen, iron rapidly reprecipitates, forming a particulate maximum and rescavenging {sup 210}Pb. Unlike {sup 210}Pb, much {sup 210}Po is released from sediments before overlying water becomes completely anoxic, leading to unsupported {sup 210}Po. {sup 210}Po cycling in the stratified water column is more complex than that of {sup 210}Pb, and additional removal mechanism(s) may be active, including perhaps oxidation of soluble Po(II) to insoluble Po(IV).

  12. Arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in feathers of Black-legged Kittiwake (Rissa tridactyla) and Black Oystercatcher (Haematopus bachmani) from Prince William Sound, Alaska.

    PubMed

    Burger, Joanna; Gochfeld, Michael; Sullivan, Kelsey; Irons, David; McKnight, Aly

    2008-07-15

    Arsenic, cadmium, chromium, lead, manganese, mercury and selenium were analyzed in the feathers of Black-legged Kittiwakes (Rissa tridactyla) from Shoup Bay in Prince William Sound, Alaska to determine if there were age-related differences in metal levels, and in Black Oystercatchers (Haematopus bachmani)) from the same region to determine if there were differences in oiled and unoiled birds. Except for mercury, there were no age-related differences in metals levels in the feathers of kittiwakes. Kittiwakes over 13 years of age had the highest levels of mercury. There were no differences in levels of metals in the feathers of oystercatchers from oiled and unoiled regions of Prince William Sound. Except for mercury, the feathers of oystercatchers had significantly higher levels of all metals than those of kittiwakes. Levels of mercury in kittiwake feathers (mean of 2910 ng/g [ppb]) were within the range of many species of seabirds reported for other studies, and were generally below adverse effects levels. PMID:18440597

  13. Role of the metal in the bonding and properties of bimetallic complexes involving manganese, iron, and cobalt.

    PubMed

    Tereniak, Stephen J; Carlson, Rebecca K; Clouston, Laura J; Young, Victor G; Bill, Eckhard; Maurice, Rémi; Chen, Yu-Sheng; Kim, Hyun Jung; Gagliardi, Laura; Lu, Connie C

    2014-02-01

    A multidentate ligand platform is introduced that enables the isolation of both homo- and heterobimetallic complexes of divalent first-row transition metal ions such as Mn(II), Fe(II), and Co(II). By means of a two-step metalation strategy, five bimetallic coordination complexes were synthesized with the general formula M1M2Cl(py3tren), where py3tren is the triply deprotonated form of N,N,N-tris(2-(2-pyridylamino)ethyl)amine. The metal-metal pairings include dicobalt (1), cobalt-iron (2), cobalt-manganese (3), diiron (4), and iron-manganese (5). The bimetallic complexes have been investigated by X-ray diffraction and X-ray anomalous scattering studies, cyclic voltammetry, magnetometry, Mössbauer spectroscopy, UV-vis-NIR spectroscopy, NMR spectroscopy, combustion analyses, inductively coupled plasma optical emission spectrometry, and ab initio quantum chemical methods. Only the diiron chloride complex in this series contains a metal-metal single bond (2.29 Å). The others show weak metal-metal interactions (2.49 to 2.53 Å). The diiron complex is also distinct with a septet ground state, while the other bimetallic species have much lower spin states from S = 0 to S = 1. We propose that the diiron system has delocalized metal-metal bonding electrons, which seems to correlate with a short metal-metal bond and a higher spin state. Multiconfigurational wave function calculations revealed that, indeed, the metal-metal bonding orbitals in the diiron complex are much more delocalized than those of the dicobalt analogue. PMID:24125042

  14. Altered Manganese Homeostasis and Manganese Toxicity in a Huntington's Disease Striatal Cell Model Are Not Explained by Defects in the Iron Transport System

    PubMed Central

    Williams, B. Blairanne; Kwakye, Gunnar F.; Wegrzynowicz, Michal; Aschner, Michael; Erikson, Keith M.; Bowman, Aaron B.

    2010-01-01

    Expansion of a polyglutamine tract in Huntingtin (Htt) leads to the degeneration of medium spiny neurons in Huntington's disease (HD). Furthermore, the HTT gene has been functionally linked to iron (Fe) metabolism, and HD patients show alterations in brain and peripheral Fe homeostasis. Recently, we discovered that expression of mutant HTT is associated with impaired manganese (Mn) uptake following overexposure in a striatal neuronal cell line and mouse model of HD. Here we test the hypothesis that the transferrin receptor (TfR)–mediated Fe uptake pathway is responsible for the HD-associated defects in Mn uptake. Western blot analysis showed that TfR levels are reduced in the mutant STHdhQ111/Q111 striatal cell line, whereas levels of the Fe and Mn transporter, divalent metal transporter 1 (DMT1), are unchanged. To stress the Fe transport system, we exposed mutant and wild-type cells to elevated Fe(III), which revealed a subtle impairment in net Fe uptake only at the highest Fe exposures. In contrast, the HD mutant line exhibited substantial deficits in net Mn uptake, even under basal conditions. Finally, to functionally evaluate a role for Fe transporters in the Mn uptake deficit, we examined Mn toxicity in the presence of saturating Fe(III) levels. Although Fe(III) exposure decreased Mn neurotoxicity, it did so equally for wild-type and mutant cells. Therefore, although Fe transporters contribute to Mn uptake and toxicity in the striatal cell lines, functional alterations in this pathway are insufficient to explain the strong Mn resistance phenotype of this HD cell model. PMID:20547568

  15. Chemically bonded phosphate ceramics of trivalent oxides of iron and manganese

    DOEpatents

    Wagh, Arun S. (Orland Park, IL); Jeong, Seung-Young (Westmont, IL)

    2002-01-01

    A new method for combining elemental iron and other metals to form an inexpensive ceramic to stabilize arsenic, alkaline red mud wastes, swarfs, and other iron or metal-based additives, to create products and waste forms which can be poured or dye cast.

  16. Inhibition of Ape1 nuclease activity by lead, iron, and cadmium.

    PubMed Central

    McNeill, Daniel R; Narayana, Avinash; Wong, Heng-Kuan; Wilson, David M

    2004-01-01

    Many environmental metals are co-carcinogens, eliciting their effects via inhibition of DNA repair. Apurinic/apyrimidinic (AP) endonuclease 1 (Ape1) is the major mammalian abasic endonuclease and initiates repair of this cytotoxic/mutagenic lesion by incising the DNA backbone via a Mg(2+)-dependent reaction. In this study we examined the effects of arsenite [As(III)], cadmium [Cd(II)], cobalt [Co(II)], iron [Fe(II)], nickel [Ni(II)], and lead [Pb(II)] at concentrations ranging from 0.3 to 100 microM on the incision activity of Ape1 in the presence of 1 mM MgCl(subscript)2(/subscript). Pb(II) and Fe(II) inhibited Ape1 activity at each of the concentrations tested, with an IC(subscript)50(/subscript) (half-maximal inhibitory concentration) of 0.61 and 1.0 microM, respectively. Cd(II) also inhibited Ape1 activity but only at concentrations > 10 microM. No inhibition was seen with As(III), Co(II), or Ni(II). A similar inhibition pattern was observed with the homologous Escherichia coli protein, exonuclease III, but no inhibition was seen with the structurally distinct AP endonuclease E. coli endonuclease IV, indicating a targeted effect of Pb(II), Fe(II), and Cd(II) on the Ape1-like repair enzymes. Excess nonspecific DNA did not abrogate the metal inactivation, suggesting a protein-specific effect. Notably, Cd(II), Fe(II), and Pb(II) [but not As(III), Co(II), or Ni(II)] inhibited AP endonuclease activity in whole-cell extracts but had no significant effect on single nucleotide gap filling, 5'-flap endonuclease, and nick ligation activities, supporting the idea of selective inactivation of Ape1 in cells. Our results are the first to identify a potential DNA repair enzyme target for lead and suggest a means by which these prevalent environmental metals may elicit their deleterious effects. PMID:15159209

  17. The alternative aerobic ribonucleotide reductase of Escherichia coli, NrdEF, is a manganese-dependent enzyme that enables cell replication during periods of iron starvation

    PubMed Central

    Martin, Julia E.; Imlay, James A.

    2011-01-01

    The genome of Escherichia coli encodes two class I ribonucleotide reductases. The first, NrdAB, is a well-studied iron-dependent enzyme that is essential for aerobic growth. The second, NrdEF, is not functional under routine conditions, and its role is obscure. Recent studies demonstrated that NrdEF can be activated in vitro by manganese as well as iron. Since iron enzymes are potential targets for hydrogen peroxide, and since the nrdHIEF operon is induced during H2O2 stress, we hypothesized that H2O2 might inactivate NrdAB and that NrdEF might be induced to compensate. This idea was tested using E. coli mutants that are chronically stressed by H2O2. Contrary to expectation, NrdAB remained active. Its resistance to H2O2 depended upon YfaE, which helps to activate NrdB. The induction of NrdEF during H2O2 stress was mediated by the inactivation of Fur, an iron-dependent repressor. This regulatory arrangement implied that NrdEF has a physiological role during periods of iron starvation. Indeed, NrdEF supported cell replication in iron-depleted cells. Iron bound to NrdF when it was expressed in iron-rich cells, but NrdEF was functional only in cells that were both iron-depleted and manganese-rich. Thus NrdEF supports DNA replication when iron is unavailable to activate the housekeeping NrdAB enzyme. PMID:21338418

  18. Effects of dietary cadmium exposure on tissue-specific cadmium accumulation, iron status and expression of iron-handling and stress-inducible genes in rainbow trout: influence of elevated dietary iron.

    PubMed

    Kwong, Raymond W M; Andrés, Jose A; Niyogi, Som

    2011-03-01

    Recent evidences suggest that dietary cadmium (Cd) uptake likely occurs via the dietary iron (Fe) uptake pathway in freshwater fish, at least in part. The present study investigated the interactive effects of dietary Cd and Fe in juvenile rainbow trout (Oncorhynchus mykiss). Fish were treated for four weeks with four different diets: normal Fe, high Fe, normal Fe plus Cd, and high Fe plus Cd. Physiological parameters, tissue-specific Fe and Cd level, plasma Fe status, and tissue-specific mRNA expression of transferrin, metallothioneins (MT-A and MT-B) and heat shock proteins 70 (HSP70a and HSP70b) were analyzed. Exposure to dietary Cd increased Cd burden in the following order: intestine>kidney>stomach>liver>gill>carcass. Interestingly, high dietary Fe reduced Cd accumulation in the stomach and intestine as well as in the wholebody of fish. Dietary Cd increased hepatic transferrin mRNA expression and total Fe binding capacity in the plasma, indicating the effect of Cd on Fe handling in fish. The mRNA expression of MTs and HSP70s was also increased in various tissues following dietary Cd exposure, however the response profile of different MT and HSP70 genes was not consistent among different tissues. In general, MT-A was more responsive to Cd exposure in the intestine and liver, whereas MT-B was more responsive in the kidney. Similarly, HSP70a expression was more sensitive to Cd exposure than HSP70b, particularly in the intestine. Interestingly, high Fe diet suppressed Cd-induced induction of transferrin, MT and HSP70 genes in various tissues. Overall, our study suggests that elevated dietary Fe can reduce Cd accumulation and ameliorate Cd-induced stress responses in freshwater fish. PMID:21371606

  19. Comparative electrochemistry and electrocatalytic activities of cobalt, iron and manganese phthalocyanine complexes axially co-ordinated to mercaptopyridine self-assembled monolayer at gold electrodes

    Microsoft Academic Search

    Kenneth I. Ozoemena; Tebello Nyokong

    2006-01-01

    Comparative surface electrochemistry and electrocatalytic properties of solid ultrathin monolayer films of metallophthalocyanine (MPc) complexes of cobalt (CoPc), iron (FePc) and manganese (MnPc) self-immobilised, via axial ligation reaction, onto preformed 4-mercaptopyridine self-assembled monolayers (SAMs) on gold electrodes have been described. Surface electrochemical parameters of the modified electrodes showed that these MPc-SAMs are densely packed with flat orientations. The electrochemical, electrocatalytic

  20. RESPONSE OF ‘GRANNY SMITH’ APPLE TREES TO FOLIAR TITANIUM SPRAYS UNDER CONDITIONS OF LOW SOIL AVAILABILITY OF IRON, MANGANESE, AND ZINC

    Microsoft Academic Search

    Pawe? Wójcik; Hamide Gubbuk; Hüseyin Akgül; Esma Gunes; Kadir Ucgun; Hakk? Koçal; Cenk Küçükyumuk

    2010-01-01

    The aim of the study was to examine impact of foliar titanium (Ti) sprays on vegetative and reproductive response of apple (Malus domestica Borkh.) trees under conditions of low soil availability of iron (Fe), manganese (Mn), and zinc (Zn). The experiment was conducted during 2005–2006 at a Experimental Station in Isparta region, Turkey, on mature ‘Granny Smith’ apple trees\\/M.9, planted

  1. Elevated Airborne Exposures of Teenagers to Manganese, Chromium, and Iron from Steel Dust and New York City’s Subway System

    PubMed Central

    CHILLRUD, STEVEN N.; EPSTEIN, DAVID; ROSS, JAMES M.; SAX, SONJA N.; PEDERSON, DEE; SPENGLER, JOHN D.; KINNEY, PATRICK L.

    2011-01-01

    There is increasing interest in potential health effects of airborne exposures to hazardous air pollutants at relatively low levels. This study focuses on sources, levels, and exposure pathways of manganese, chromium, and iron among inner-city high school students in New York City (NYC) and the contribution of subways. Samples of fine particulate matter (PM2.5) were collected during winter and summer over 48 h periods in a variety of settings including inside homes, outdoors, and personal samples (i.e., sampling packs carried by subjects). PM2.5 samples were also collected in the NYC subway system. For NYC, personal samples had significantly higher concentrations of iron, manganese, and chromium than did home indoor and ambient samples. The ratios and strong correlations between pairs of elements suggested steel dust as the source of these metals for a large subset of the personal samples. Time–activity data suggested NYC subways as a likely source of these elevated personal metals. In duplicate PM2.5 samples that integrated 8 h of underground subway exposure, iron, manganese, and chromium levels (>2 orders of magnitude above ambient levels) and their ratios were consistent with the elevated personal exposures. Steel dust in the NYC subway system was the dominant source of airborne exposures to iron, manganese, and chromium for many young people enrolled in this study, with the same results expected for other NYC subway riders who do not have occupational exposures to these metals. However, there are currently no known health effects at the exposure levels observed in this study. PMID:14968857

  2. Effects of Dietary Nickel and Protein on Growth, Nitrogen Metabolism and Tissue Concentrations of Nickel, Iron, Zinc, Manganese and Copper in Calves1

    Microsoft Academic Search

    JERRY W. SPEARS; R. W. HARVEY

    Thirty male calves were used in a 2 x 3 factorial arrangement of treatments to determine the effects of dietary nickel and protein on performance, urease activity and tissue concentrations of nickel, iron, zinc, copper and manganese Protein levels evaluated were 10.0, 12.25 and 14.5%, and nickel was supplemented at a level of 0 or 5 mg\\/kg of diet. Nickel

  3. Metallation and mismetallation of iron and manganese proteins in vitro and in vivo: the class I ribonucleotide reductases as a case study

    PubMed Central

    Cotruvo, Joseph A.; Stubbe, JoAnne

    2012-01-01

    How cells ensure correct metallation of a given protein and whether a degree of promiscuity in metal binding has evolved are largely unanswered questions. In a classic case, iron- and manganese-dependent superoxide dismutases (SODs) catalyze the disproportionation of superoxide using highly similar protein scaffolds and nearly identical active sites. However, most of these enzymes are active with only one metal, although both metals can bind in vitro and in vivo. Iron(II) and manganese(II) bind weakly to most proteins and possess similar coordination preferences. Their distinct redox properties suggest that they are unlikely to be interchangeable in biological systems except when they function in Lewis acid catalytic roles, yet recent work suggests this is not always the case. This review summarizes the diversity of ways in which iron and manganese are substituted in similar or identical protein frameworks. As models, we discuss (1) enzymes, such as epimerases, thought to use FeII as a Lewis acid under normal growth conditions but which switch to MnII under oxidative stress; (2) extradiol dioxygenases, which have been found to use both FeII and MnII, the redox role of which in catalysis remains to be elucidated; (3) SODs, which use redox chemistry and are generally metal-specific; and (4) the class I ribonucleotide reductases (RNRs), which have evolved unique biosynthetic pathways to control metallation. The primary focus is the class Ib RNRs, which can catalyze formation of a stable radical on a tyrosine residue in their ?2 subunits using either a di-iron or a recently characterized dimanganese cofactor. The physiological roles of enzymes that can switch between iron and manganese cofactors are discussed, as are insights obtained from the studies of many groups regarding iron and manganese homeostasis and the divergent and convergent strategies organisms use for control of protein metallation. We propose that, in many of the systems discussed, “discrimination” between metals is not performed by the protein itself, but it is instead determined by the environment in which the protein is expressed. PMID:22991063

  4. Relationships between chemical forms of soil iron and manganese and their absorption by rice from 34 flooded Gulf Coast soils of Texas 

    E-print Network

    Phillips, Douglas Patton

    1971-01-01

    RELATIONSHIPS BETHFEN CHEHICAL FOPHS OF SOIL IRON AND HANGANESE AND THEIP, ABSOPPT ION BY RICE FROH 34 FLOODED GULF COAST SOILS OF TEXAS A Thesis by Douglas Patton Phillips Sub"nitted to the Graduate College of Texas MH University in partial... fulfillment of the requirement for the degree of YESTER OF SCIENCE December 1 971 Yidjor Subject: 5011 Ch lilistry m A H 0 0 m m i III RELATIONSHIPS BETWEEN CHEMICAL FORMS OF SOIL IRON AND MANGANESE AND THEIR ABSORPTION BY RICE FROM 34 FLOODED...

  5. Exposure to bis(maltolato)oxovanadium(IV) increases levels of hepcidin mRNA and impairs the homeostasis of iron but not that of manganese.

    PubMed

    Sánchez-González, Cristina; Rivas-García, Lorenzo; López-Chaves, Carlos; Rodríguez-Nogales, Alba; Algieri, Francesca; Gálvez, Julio; Gómez-Aracena, Jorge; Vera-Ramírez, Laura; Montes-Bayon, Maria; Sanz-Medel, Alfredo; Llopis, Juan

    2014-11-01

    The aim of this study was to examine whether alterations in iron homeostasis, caused by exposure to vanadium, are related to changes in the gene expression of hepatic hepcidin. Two groups of rats were examined: control and vanadium-exposed. Vanadium, as bis(maltolato)oxovanadium(IV) was supplied in the drinking water. The experiment had a duration of five weeks. Iron and manganese were measured in excreta, serum and tissues. Leptin, ferritin, IL-1?, IL-6, TNF-?, red blood cells, haemoglobin and haematocrit were determined. Protein carbonyl group levels and hepcidin gene expression were determined in the liver. In the vanadium-exposed rats, iron absorption, serum iron and leptin and all haematological parameters decreased. Levels of IL-6, TNF-? and ferritin in serum and of iron in the liver, spleen and heart increased. In the liver, levels of protein carbonyl groups and hepcidin mRNA were also higher in the vanadium-exposed group. Exposure to vanadium did not modify manganese homeostasis. The results obtained from this study provide the first evidence that bis(maltolato)oxovanadium(IV) produces an increase in the gene expression of the hepcidin, possibly caused by an inflammatory process. Both factors could be the cause of alterations in Fe homeostasis and the appearance of anaemia. However, Mn homeostasis was not affected. PMID:25168077

  6. Iron as a possible aggravating factor for osteopathy in itai-itai disease, a disease associated with chronic cadmium intoxication

    SciTech Connect

    Noda, M.; Yasuda, M.; Kitagawa, M. (Toyama Medical and Pharmaceutical Univ. (Japan))

    1991-03-01

    Itai-itai disease is thought to be the result of chronic cadmium (Cd) intoxication. We examined 23 autopsy cases of itai-itai disease and 18 cases of sudden death as controls. Urine and blood samples from 10 patients were collected before they died and revealed the presence of severe anemia and renal tubular injuries. Undecalcified sections of iliac bone were stained with Aluminon reagent, and ammonium salt of aurintricarboxylic acid, and Prussian blue reagent in all cases of itai-itai disease. These two reagents reacted at the same mineralization fronts. X-ray microanalysis revealed the presence of iron at mineralization fronts in itai-itai disease. Five patients showed evidence of hemosiderosis in the liver, spleen, and pancreas, probably as a result of post transfusion iron overload. Renal calculi and calcified aortic walls were also stained with Prussian blue reagent in several patients. Neither ferritin nor transferrin were visualized at mineralization fronts in itai-itai disease by immunohistochemical staining. These results suggest that iron is bound to calcium or to calcium phosphate by a physicochemical reaction. A marked osteomalacia was observed in 10 cases of itai-itai disease by histomorphometry. Regression analyses of data from cases of itai-itai disease suggested that an Aluminon-positive metal inhibited mineralization and that renal tubules were injured. Since bone Cd levels were increased in itai-itai disease, it is likely that renal tubules were injured by exposure to Cd. Therefore, stainable bone iron is another possible aggravating factor for osteopathy in itai-itai disease, and a synergistic effect between iron and Cd on mineralization is proposed.

  7. Shelf-to-basin shuttling of iron and manganese as a driver of phosphorus burial in the Landsort Deep during past periods of hypoxia

    NASA Astrophysics Data System (ADS)

    Dijkstra, Nikki; Slomp, Caroline P.; Ash, Jeanine; Bauersachs, Thorsten; Hardisty, Dalton; Martin, Ellen; Riedinger, Natascha

    2015-04-01

    Bottom water hypoxia (i.e. low oxygen conditions) in coastal systems is an increasing world-wide problem. Enhanced external phosphorus inputs may contribute to the development of hypoxia by increasing primary production in the water column. The associated elevated flux of organic matter to the seafloor may then result in an oxygen demand in bottom waters that outpaces supply. The mechanisms leading to removal of phosphorus from the Baltic Sea system through burial in the sediment are still incompletely understood. The Baltic Sea is currently hypoxic and has experienced two earlier periods of hypoxia during the Holocene. These are the Holocene Thermal Maximum (ca 8000-4000 yrs ago) and the Medieval Climate Anomaly (ca 700-1000 yrs ago) (Zillen et al., 2008). Based on sediment records for the Gotland Deep area, Jilbert and Slomp (2013) suggest that particle shuttles of iron and manganese oxides from the shelves act as drivers for authigenesis of phosphorus-bearing minerals in the deep euxinic basins. Here, we present geochemical results for a long sediment record (0 - 90 mbsf) from the deepest basin in the Baltic Sea (Landsort Deep, 451 m, Site M0063), which was retrieved during the International Ocean Discovery Programme (IODP) Baltic Sea Paleoenvironment Expedition 347 in 2013. Bulk sediment and pore water geochemical analyses, results of sequential extractions for phosphorus, iron and sulfur, and various micro-analyses are combined to assess whether shelf-to-basin shuttling of manganese and iron affects the long-term burial of phosphorus in the Landsort Deep. We find that highly organic-rich sediments were deposited in the Landsort Deep following the transition from a lacustrine to a brackish/marine environment. This is reflected, for example, in the organic carbon content and pore water geochemistry. Elevated molybdenum and organic carbon/phosphorus ratios in the sediment allow the two major hypoxic periods during the early and mid-Holocene to be identified. All sediments, but particularly sediments which were deposited during these two hypoxic periods, contain high concentrations of phosphorus, manganese, iron/aluminum and calcium. Results of sequential phosphorus extractions using the SEDEX method suggest that iron-bound phosphates and authigenic calcium phosphates are major phosphorus burial phases in the Landsort Deep throughout the whole Holocene but especially during the hypoxic periods. Vivianite crystals (>63 ?m, reduced iron phosphates) were observed at various depths within the sediment record and were characterized with XRD, SEM/EDX and XAS. We propose that the enhanced formation and burial of P-bearing minerals in the Landsort Deep during past periods of hypoxia are closely coupled to the shuttling of manganese and iron into this deep basin.

  8. Bioaccumulation of iron, zinc, cadmium and chromium by juvenile snail Limicolaria aurora J., fed edible mushroom Pleurotus spp from Niger Delta, Nigeria.

    PubMed

    Ebenso, I E; Solomon, I P; Akoje, C C; Akpan, I P; Eko, P M; Akpan, E A; Omole, A J

    2013-03-01

    The effects of uptake of metals (iron, zinc, cadmium and chromium) by juvenile snail Limicolaria aurora fed edible mushroom Pleurotus spp from 3 contaminated farm sites and a laboratory grown species (control) respectively were investigated. The 120 snails were fed in plastic snaileries for 4 weeks in the laboratory. Control site was risk free. Metal uptake was low and bioaccumulation in L. aurora tissue was below FAO/WHO standard of 1 mg/kg for chromium and cadmium. Snails were considered safe for consumption. PMID:23229305

  9. Spatio-temporal Distribution and Chemical Speciation of Iron and Manganese in Sediments from Lake Aha, China

    NASA Astrophysics Data System (ADS)

    Liu, Feng; Hu, Jiwei; Qin, Fanxin; Jiang, Cuihong; Huang, Xianfei; Deng, Jiajun; Li, Cunxiong

    2010-11-01

    This paper reports an investigation on pollution and potential risk on elements of iron (Fe) and manganese (Mn) in sediments from Lake Aha, which is a drinking-water source for Guiyang City, the capital of Guizhou Province in southwestern China. In the present research, chemical speciation of Fe and Mn in sediments from the lake was studied based on the sequential extraction procedure developed by Tessier et al.. The results obtained from the study are as follows. The average values of total Fe were 47617 mg/kg and 70325 mg/kg in sediments from the lake in summer and winter respectively, and its speciation consisted mainly of residual and Fe-Mn oxides fractions. The amounts of total Fe and the distribution of its speciation in the sediments should be affected by effluents from a large quantity of deserted coal mines in the lake basin in summer and winter. The average values of total Mn were 7996 mg/kg and 1753 mg/kg in summer and winter respectively, and its speciation is primarily comprised of carbonate and Fe-Mn oxides fractions. The amounts of total Mn and its distribution in different fractions in the sediments were believed to be primarily influenced by effluents from those deserted coal mines in summer and by the condition of redox interface in winter.

  10. Matrix isolation infrared spectra, assignment and DFT investigation on reactions of iron and manganese monoxides with CH3Cl.

    PubMed

    Zhao, Yanying; Fan, Kexue; Huang, Yongfei; Zheng, Xuming

    2013-12-01

    The reactions of iron and manganese monoxide molecules (FeO, and MnO) with monochloromethane in solid argon have been studied by matrix isolation infrared spectroscopy and quantum chemistry calculations. When annealing, the reactions of FeO and MnO with CH3Cl first form the OM-(?(Cl)-CH3Cl) (MMn, Fe) complexes, which can isomerize to CH3MOCl (MMn, Fe) upon 300

  11. Rapid removal and separation of iron(II) and manganese(II) from micropolluted water using magnetic graphene oxide.

    PubMed

    Yan, Han; Li, Haijiang; Tao, Xue; Li, Kun; Yang, Hu; Li, Aimin; Xiao, Shoujun; Cheng, Rongshi

    2014-06-25

    A novel two-dimensional carbon-based magnetic nanomaterial, magnetic graphene oxide (MGO), was prepared and then used as an efficient adsorbent. MGO showed rapid and complete removal of iron(II) (Fe) and manganese(II) (Mn) from micropolluted water bodies over a wide pH range. After saturated adsorption, MGO could be rapidly separated from water under an external magnetic field. Results of the adsorption equilibrium study indicated that the adsorption of Fe and Mn by MGO took place via monolayer heterogeneous and spontaneous processes resulting from the heterogeneity of the MGO surface as well as from the electrostatic interactions between surface acidic groups of MGO and metal ions. In addition, both the Fe and Mn uptake of MGO was very slightly affected by NaCl, although it decreased with increased humic acid in solutions. In an Fe/Mn binary aqueous system, both metal ions can be efficiently removed at low concentrations, but MGO showed preferential adsorption of Fe in a concentrated aqueous mixture. The adsorption behavior in the binary system was due to different affinities of surface oxygen-containing functional groups on MGO to Fe and Mn. Finally, unlike traditional approaches in recycling and reusing an adsorbent, the Fe- and Mn-loaded MGO can be directly applied as a new adsorbent to achieve the efficient removal of fluoride from aqueous solutions. PMID:24787443

  12. The abundance of iron-peak elements and the dust composition in eta Carinae: manganese

    Microsoft Academic Search

    M. A. Bautista; M. Meléndez; H. Hartman; T. R. Gull; K. Lodders

    2011-01-01

    We study the chemical abundances of the strontium filament found in the ejecta of eta Carinae. In particular, we derive the abundances of iron-peak elements from the spectra of their singly ionized ions present in the optical\\/infrared (IR) spectra. In this paper we analyse the spectrum of Mn II using a new non-local thermodynamic equilibrium (non-LTE) model for this system.

  13. Effect of carbon type and particle size on the reduction of iron, phosphorus, and manganese

    SciTech Connect

    Fedotov, A.O.

    1986-01-01

    Because of the desirability of creating waste-free technologies, efficient use of phosphate slags from the iron and steel industry currently attracts special attention. Phosphate-iron slag was selected as the subject for reduction because this material has a modulus of acidity of 0.8, giving minimum viscosity and consequently maximum rate of reduction. To determine the chemical activity of the different carbons, the authors studied the selective reduction of the elements in the slag using coke, lean coal, graphite, and KAU coke as reducing agents. To clarify the effect of the particle size on the rate of reduction of the slag elements, the authors carried out experiments using different fractions of coke as reducing agents. A graph of the relationship between process rate and particle size is shown in a figure. It was concluded that the rate of reduction of the elements of a slag by carbon depends on the particle size of the reducing agent and is at a maximum when using the 2-4 mm fraction. The maximum activity with respect to a phosphate-iron slag melt is shown by KAU coke.

  14. Relationship of manganese-iron oxides and associated heavy metals to grain size in stream sediments

    USGS Publications Warehouse

    Whitney, P.R.

    1975-01-01

    The distribution of ammonium citrate-leachable lead, zinc and cadmium among size fractions in stream sediments is strongly influenced by the presence of hydrous Mn-Fe oxides in the form of coatings on sediment grains. Distribution curves showing leachable metals as a function of particle size are given for eight samples from streams in New York State. These show certain features in common; in particular two concentrations of metals, one in the finest fractions, and a second peak in the coarse sand and gravel fraction. The latter can be explained as a result of the increasing prevalence and thickness of oxide coatings with increasing particle size, with the oxides serving as collectors for the heavy metals. The distribution of Zn and Cd in most of the samples closely parallels that of Mn; the distribution of Pb is less regular and appears to be related to Fe in some samples and Mn in others. The concentration of metals in the coarse fractions due to oxide coatings, combined with the common occurrence of oxide deposition in streams of glaciated regions, raises the possibility of using coarse materials for geochemical surveys and environmental heavy-metal studies. ?? 1975.

  15. Structural and magnetic properties of the iron substituted lithium manganese spinel oxides

    NASA Astrophysics Data System (ADS)

    Wolska, Emilia; Tovar, Michael; Andrzejewski, Bartlomiej; Nowicki, Waldemar; Darul, Jolanta; Piszora, Pawel; Knapp, Michael

    2006-01-01

    Most studies on the lithium-manganese oxide as a cathode material have concentrated on the stabilization of the cubic spinel structure, mainly by doping other transition metal ions into LiMn 2O 4 lattice. Partial substitution of Fe 3+ ions for Mn 3+ restrains the Jahn-Teller effect, owing to the reduction of Mn 3+/Mn 4+ ratio. In LiFe 0.1Mn 1.9O 4 spinel oxide the phase transitions from cubic to orthorhombic and/or tetragonal structure, appearing for LiMn 2O 4 below the room temperature, may be totally suppressed. The changes in stoichiometry of LiFe xMn 2- xO 4 system, modify the sequence of phase transitions and lower the transition temperature. A superexchange magnetic interaction between the Mn ions via oxygen atoms alters, with the Fe 3+-content in Li xMn 3- xO 4 increasing from x=0.0-0.1, showing the antiferromagnetic ordering at very low temperature. The Néel point increases from 7 to 27 K. Effect of Fe 3+ ions substitution in the LiFe xMn 2- xO 4 system on its low-temperature structural phase transitions, have been investigated using high-resolution synchrotron X-ray powder diffraction, neutron powder diffraction and the magnetic susceptibility measurements. Divergences appear in the interpretation of magnetic structure on the basis of experimental results, acquired from neutron diffraction data, and obtained from the direct current susceptibility measurements.

  16. Comparison of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in feathers in bald eagle (Haliaeetus leucocephalus), and comparison with common eider (Somateria mollissima), glaucous-winged gull (Larus glaucescens), pigeon guillemot (Cepphus columba), and tufted puffin (Fratercula cirrhata) from the Aleutian Chain of Alaska

    PubMed Central

    Burger, Joanna; Gochfeld, Michael

    2014-01-01

    There is an abundance of field data for levels of metals from a range of places, but relatively few from the North Pacific Ocean and Bering Sea. In this paper we examine the levels of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in feathers from common eiders (Somateria mollissima), glaucous-winged gulls (Larus glaucescens), pigeon guillemots (Cepphus columba), tufted puffins (Fratercula cirrhata) and bald eagles (Haliaeetus leucocephalus) from the Aleutian Chain of Alaska. Our primary objective was to test the hypothesis that there are no trophic levels relationships for arsenic, cadmium, chromium, lead, manganese, mercury and selenium among these five species of birds breeding in the marine environment of the Aleutians. There were significant interspecific differences in all metal levels. As predicted bald eagles had the highest levels of arsenic, chromium, lead, and manganese, but puffins had the highest levels of selenium, and pigeon guillemot had higher levels of mercury than eagles (although the differences were not significant). Common eiders, at the lowest trophic level had the lowest levels of some metals (chromium, mercury and selenium). However, eiders had higher levels than all other species (except eagles) for arsenic, cadmium, lead, and manganese. Levels of lead were higher in breast than in wing feathers of bald eagles. Except for lead, there were no significant differences in metal levels in feathers of bald eagles nesting on Adak and Amchitka Island; lead was higher on Adak than Amchitka. Eagle chicks tended to have lower levels of manganese than older eagles. PMID:18521716

  17. Comparison of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in feathers in bald eagle (Haliaeetus leucocephalus), and comparison with common eider (Somateria mollissima), glaucous-winged gull (Larus glaucescens), pigeon guillemot (Cepphus columba), and tufted puffin (Fratercula cirrhata) from the Aleutian Chain of Alaska.

    PubMed

    Burger, Joanna; Gochfeld, Michael

    2009-05-01

    There is an abundance of field data for levels of metals from a range of places, but relatively few from the North Pacific Ocean and Bering Sea. In this paper we examine the levels of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in feathers from common eiders (Somateria mollissima), glaucous-winged gulls (Larus glaucescens), pigeon guillemots (Cepphus columba), tufted puffins (Fratercula cirrhata) and bald eagles (Haliaeetus leucocephalus) from the Aleutian Chain of Alaska. Our primary objective was to test the hypothesis that there are no trophic levels relationships for arsenic, cadmium, chromium, lead, manganese, mercury and selenium among these five species of birds breeding in the marine environment of the Aleutians. There were significant interspecific differences in all metal levels. As predicted bald eagles had the highest levels of arsenic, chromium, lead, and manganese, but puffins had the highest levels of selenium, and pigeon guillemot had higher levels of mercury than eagles (although the differences were not significant). Common eiders, at the lowest trophic level had the lowest levels of some metals (chromium, mercury and selenium). However, eiders had higher levels than all other species (except eagles) for arsenic, cadmium, lead, and manganese. Levels of lead were higher in breast than in wing feathers of bald eagles. Except for lead, there were no significant differences in metal levels in feathers of bald eagles nesting on Adak and Amchitka Island; lead was higher on Adak than Amchitka. Eagle chicks tended to have lower levels of manganese than older eagles. PMID:18521716

  18. Pivalate Bridged High Spin Manganese(II) and Iron(II) Polymers

    Microsoft Academic Search

    I. L. Eremenko; M. A. Kiskin; I. G. Fomina; A. A. Sidorov; G. G. Aleksandrov; V. N. Ikorskii; Yu. G. Shvedenkov; Yu. V. Rakitin; V. M. Novotortsev

    2005-01-01

       Antiferromagnetic Mn(II) polymers of general formula {[L2Mn(?-OOCCMe3)2][Mn2(?-OOCCMe3)4]}n (L = 1,2-phenylenediamine (3) and 4,5-dimethyl-1,2-phenylenediamine (4)) were synthesized from [Mn(?-OOCCMe3)2(HOEt)]\\u000a n\\u000a (1) polymer and arenediamines in MeCN solution. The tetranuclear cluster Fe4(?3-OH)2(?-OOCCMe3)4(?2-OOCCMe3)2(EtOH)6 (5) was prepared by reacting FeSO4·7H2O with KOOCCMe3 in EtOH and was used as starting pivalate iron(II) agent in further reactions. The thermolysis of 5 in MeCN was shown to

  19. The Abundance of Iron-Peak Elements and the Dust Composition in eta Carinae: Manganese

    NASA Technical Reports Server (NTRS)

    Bautista, M. A.; Melendez, M.; Hartman, H.; Gull, T. R.; Lodders, K.

    2010-01-01

    We study the chemical abundances of the Strontium Filament found in the ejecta of (eta) Carinae. In particular, we derive the abundances of iron-peak elements front spectra of their singly ionized ions present in the optical/IR spectra. In this paper we analyze the spectrum of Mn II using a new non-LTE model for this system. In constructing this models we carried out theoretical calculations of radiative transition rates and electron impact excitation rate coefficients. We find that relative to Ni the gas phase abundance ratio of Mn is roughly solar, similar to the Cr abundance but in contrast to the large enhancements in the abundances of Sc and Ti. NVe interpret this result as an indication of non-equilibrium condensation in the ejecta of (eta) Carinae.

  20. Arsenic, iron, lead, manganese, and uranium concentrations in private bedrock wells in southeastern New Hampshire, 2012-2013

    USGS Publications Warehouse

    Flanagan, Sarah M.; Belaval, Marcel; Ayotte, Joseph D.

    2014-01-01

    Trace metals, such as arsenic, iron, lead, manganese, and uranium, in groundwater used for drinking have long been a concern because of the potential adverse effects on human health and the aesthetic or nuisance problems that some present. Moderate to high concentrations of the trace metal arsenic have been identified in drinking water from groundwater sources in southeastern New Hampshire, a rapidly growing region of the State (Montgomery and others, 2003). During the past decade (2000–10), southeastern New Hampshire, which is composed of Hillsborough, Rockingham, and Strafford Counties, has grown in population by nearly 48,700 (or 6.4 percent) to 819,100. These three counties contain 62 percent of the State’s population but encompass only about 22 percent of the land area (New Hampshire Office of Energy and Planning, 2011). According to a 2005 water-use study (Hayes and Horn, 2009), about 39 percent of the population in these three counties in southeastern New Hampshire uses private wells as sources of drinking water, and these wells are not required by the State to be routinely tested for trace metals or other contaminants. Some trace metals have associated human-health benchmarks or nonhealth guidelines that have been established by the U.S. Environmental Protection Agency (EPA) to regulate public water supplies. The EPA has established a maximum contaminant level (MCL) of 10 micrograms per liter (?g/L) for arsenic (As) and a MCL of 30 ?g/L for uranium (U) because of associated health risks (U.S. Environmental Protection Agency, 2012). Iron (Fe) and manganese (Mn) are essential for human health, but Mn at high doses may have adverse cognitive effects in children (Bouchard and others, 2011; Agency for Toxic Substances and Disease Registry, 2012); therefore, the EPA has issued a lifetime health advisory (LHA) of 300 ?g/L for Mn. Recommended secondary maximum contaminant levels (SMCLs) for Fe (300 ?g/L) and Mn (50 ?g/L) were established primarily as nonhealth guidelines—based on aesthetic considerations, such as taste or the staining of laundry and plumbing fixtures—because these contaminants, at the SMCLs, are not considered to present risks to human health. Because lead (Pb) contamination of drinking water typically results from corrosion of plumbing materials belonging to water-system customers but still poses a risk to human health, the EPA established an action level (AL) of 15 ?g/L for Pb instead of an MCL or SMCL (U.S. Environmental Protection Agency, 2012). The 15-?g/L AL for Pb has been adopted by the New Hampshire Department of Environmental Services for public water systems, and if exceeded, the public water system must inform their customers and undertake additional actions to control corrosion in the pipes of the distribution system (New Hampshire Department of Environmental Services, 2013). Unlike the quality of drinking water provided by public water suppliers, the quality of drinking water obtained from private wells in New Hampshire is not regulated; consequently, private wells are sampled only when individual well owners voluntarily choose to sample them. The U.S. Geological Survey (USGS), in cooperation with the EPA New England, conducted an assessment in 2012–13 to provide private well owners and State and Federal health officials with information on the distribution of trace-metal (As, Fe, Pb, Mn, and U) concentrations in groundwater from bedrock aquifers in the three counties of southeastern New Hampshire. This fact sheet analyzes data from water samples collected by a randomly selected group of private well owners from the three-county study area and describes the major findings for trace-metal concentrations.

  1. Selenium, copper, zinc, iron and manganese content of seven meat cuts from Hereford and Braford steers fed pasture in Uruguay.

    PubMed

    Cabrera, M C; Ramos, A; Saadoun, A; Brito, G

    2010-03-01

    Tenderloin (T), eye of rump (E), striploin (S), eye round (ER), tri-tip (TT), rib-eye roll (RR) and three rib plate-flank on (RP) meat cuts were evaluated. Selenium contents ranged between 0.42 and 1.20 mg/kg wet tissue (wt) in Hereford (H) breed and between 0.49 and 1.3 mg/kg wt in Braford (B) breed. In H and B breeds, T, TT and RP, and TT and RP were the richest cuts in selenium, respectively. Copper contents ranged between 0.25 and 1.04 mg/kg wt in H, and between 0.19 and 1.09 mg/kg wt in B. In H breed, RP had significantly more Cu than ER, TT, and RR. In B breed, ER and RR show a significant lower Cu level in comparison to the other meat cuts. Zinc contents ranged between 23 and 72.7 mg/kg wt in H, and between 23 and 63.9 mg/kg wt in B. RP is the richest cut in Zn compared to the other cuts in the two breeds. Iron contents ranged between 16.4 and 48.2 mg/kg wt in H, and between 14.2 and 47.9 mg/kg wt in B. In H breed, RR shows a lower content compared to the other cuts, except RP and S. In B breed, RR had the lowest level of Fe compared to the other cuts, except RP and T. Manganese contents ranged between 0.05 and 0.17 mg/kg wt in H, and between 0.04 and 0.48 mg/kg wt in B. In H no differences were detected between cuts. In B breed, ER cut shows the highest level of Mn. PMID:20374819

  2. Reactive iron and manganese distributions in seabed sediments near small mountainous rivers off Oregon and California (USA)

    NASA Astrophysics Data System (ADS)

    Roy, Moutusi; McManus, James; Goñi, Miguel A.; Chase, Zanna; Borgeld, Jeffry C.; Wheatcroft, Robert A.; Muratli, Jesse M.; Megowan, Meghan R.; Mix, Alan

    2013-02-01

    We examined the spatial distribution of sedimentary reactive iron (FeR) and manganese (MnR) along the continental shelf near the mouth of the Umpqua River, Oregon (USA). A well-defined muddy (silt+clay) depocenter of fluvial origin characterizes this part of the Oregon margin. Reactive Fe and Mn contents are elevated within the silt-rich landward edge of the depocenter. Away from this depocenter, sediments are predominantly sandy both along the inner-shelf (<˜100 m depth) and mid-shelf (˜100-150 m depth) and have lower concentrations of reactive metals compared to the depocenter. Sediments are also muddy along the slope (>˜150 m depth) and have elevated FeR and MnR. Based on their correlation with sediment grain size, it appears that FeR and to a lesser extent MnR, are associated with mud size sediments. Reactive metal concentration is also positively correlated with organic carbon (OC) content, indicating a potentially common source. Seabed sediments from five other small, mountainous river systems (Klamath, Eel, Navarro, Russian, and Salinas) located south of Umpqua show the same general relationship between FeR and OC. Although both FeR and MnR exhibit similar relationships to grain size and OC, the relationships with MnR exhibit considerable scatter. Comparison of Umpqua River suspended sediment data with the seabed data suggests that MnR is more prone to loss from sediment particles during transit to the seabed as compared to FeR, and this difference explains why FeR maintains a reasonably tight relationship with organic carbon and particle size along the seafloor relative to MnR.

  3. Low-temperature superacid catalysis: Reactions of n - butane and propane catalyzed by iron- and manganese-promoted sulfated zirconia

    SciTech Connect

    Tsz-Keung, Cheung; d`Itri, J.L.; Lange, F.C.; Gates, B.C. [Univ. of California, Davis, CA (United States)

    1995-12-31

    The primary goal of this project is to evaluate the potential value of solid superacid catalysts of the sulfated zirconia type for light hydrocarbon conversion. The key experiments catalytic testing of the performance of such catalysts in a flow reactor fed with streams containing, for example, n-butane or propane. Fe- and Mn-promoted sulfated zirconia was used to catalyze the conversion of n-butane at atmospheric pressure, 225-450{degrees}C, and n-butane partial pressures in the range of 0.0025-0.01 atm. At temperatures <225{degrees}C, these reactions were accompanied by cracking; at temperatures >350{degrees}C, cracking and isomerization occurred. Catalyst deactivation, resulting at least in part from coke formation, was rapid. The primary cracking products were methane, ethane, ethylene, and propylene. The observation of these products along with an ethane/ethylene molar ratio of nearly 1 at 450{degrees}C is consistent with cracking occurring, at least in part, by the Haag-Dessau mechanism, whereby the strongly acidic catalyst protonates n-butane to give carbonium ions. The rate of methane formation from n-butane cracking catalyzed by Fe- and Mn-promoted sulfated zirconia at 450{degrees}C was about 3 x 10{sup -8} mol/(g of catalyst {center_dot}s). The observation of butanes, pentanes, and methane as products is consistent with Olah superacid chemistry, whereby propane is first protonated by a very strong acid to form a carbonium ion. The carbonium ion then decomposes into methane and an ethyl cation which undergoes oligocondensation reactions with propane to form higher molecular weight alkanes. The results are consistent with the identification of iron- and manganese-promoted sulfated zirconia as a superacid.

  4. Biodistribution and acute toxicity of a nanofluid containing manganese iron oxide nanoparticles produced by a mechanochemical process

    PubMed Central

    Bellusci, Mariangela; La Barbera, Aurelio; Padella, Franco; Mancuso, Mariateresa; Pasquo, Alessandra; Grollino, Maria Giuseppa; Leter, Giorgio; Nardi, Elisa; Cremisini, Carlo; Giardullo, Paola; Pacchierotti, Francesca

    2014-01-01

    Superparamagnetic iron oxide nanoparticles are candidate contrast agents for magnetic resonance imaging and targeted drug delivery. Biodistribution and toxicity assessment are critical for the development of nanoparticle-based drugs, because of nanoparticle-enhanced biological reactivity. Here, we investigated the uptake, in vivo biodistribution, and in vitro and in vivo potential toxicity of manganese ferrite (MnFe2O4) nanoparticles, synthesized by an original high-yield, low-cost mechanochemical process. Cultures of murine Balb/3T3 fibroblasts were exposed for 24, 48, or 72 hours to increasing ferrofluid concentrations. Nanoparticle cellular uptake was assessed by flow-cytometry scatter-light measurements and microscopy imaging after Prussian blue staining; cytotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony-forming assays. After a single intravenous injection, in vivo nanoparticle biodistribution and clearance were evaluated in mice by Mn spectrophotometric determination and Prussian blue staining in the liver, kidneys, spleen, and brain at different posttreatment times up to 21 days. The same organs were analyzed for any possible histopathological change. The in vitro study demonstrated dose-dependent nanoparticle uptake and statistically significant cytotoxic effects from a concentration of 50 ?g/mL for the MTT assay and 20 ?g/mL for the colony-forming assay. Significant increases in Mn concentrations were detected in all analyzed organs, peaking at 6 hours after injection and then gradually declining. Clearance appeared complete at 7 days in the kidneys, spleen, and brain, whereas in the liver Mn levels remained statistically higher than in vehicle-treated mice up to 3 weeks postinjection. No evidence of irreversible histopathological damage to any of the tested organs was observed. A comparison of the lowest in vitro toxic concentration with the intravenously injected dose and the administered dose of other ferrofluid drugs currently in clinical practice suggests that there might be sufficient safety margins for further development of our formulation. PMID:24790434

  5. Biodistribution and acute toxicity of a nanofluid containing manganese iron oxide nanoparticles produced by a mechanochemical process.

    PubMed

    Bellusci, Mariangela; La Barbera, Aurelio; Padella, Franco; Mancuso, Mariateresa; Pasquo, Alessandra; Grollino, Maria Giuseppa; Leter, Giorgio; Nardi, Elisa; Cremisini, Carlo; Giardullo, Paola; Pacchierotti, Francesca

    2014-01-01

    Superparamagnetic iron oxide nanoparticles are candidate contrast agents for magnetic resonance imaging and targeted drug delivery. Biodistribution and toxicity assessment are critical for the development of nanoparticle-based drugs, because of nanoparticle-enhanced biological reactivity. Here, we investigated the uptake, in vivo biodistribution, and in vitro and in vivo potential toxicity of manganese ferrite (MnFe2O4) nanoparticles, synthesized by an original high-yield, low-cost mechanochemical process. Cultures of murine Balb/3T3 fibroblasts were exposed for 24, 48, or 72 hours to increasing ferrofluid concentrations. Nanoparticle cellular uptake was assessed by flow-cytometry scatter-light measurements and microscopy imaging after Prussian blue staining; cytotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony-forming assays. After a single intravenous injection, in vivo nanoparticle biodistribution and clearance were evaluated in mice by Mn spectrophotometric determination and Prussian blue staining in the liver, kidneys, spleen, and brain at different posttreatment times up to 21 days. The same organs were analyzed for any possible histopathological change. The in vitro study demonstrated dose-dependent nanoparticle uptake and statistically significant cytotoxic effects from a concentration of 50 ?g/mL for the MTT assay and 20 ?g/mL for the colony-forming assay. Significant increases in Mn concentrations were detected in all analyzed organs, peaking at 6 hours after injection and then gradually declining. Clearance appeared complete at 7 days in the kidneys, spleen, and brain, whereas in the liver Mn levels remained statistically higher than in vehicle-treated mice up to 3 weeks postinjection. No evidence of irreversible histopathological damage to any of the tested organs was observed. A comparison of the lowest in vitro toxic concentration with the intravenously injected dose and the administered dose of other ferrofluid drugs currently in clinical practice suggests that there might be sufficient safety margins for further development of our formulation. PMID:24790434

  6. No significant effect of iron deficiency on cadmium body burden or kidney dysfunction among women in the general population in Japan

    Microsoft Academic Search

    T. Tsukahara; T. Ezaki; J. Moriguchi; K. Furuki; Y. Fukui; H. Ukai; S. Okamoto; H. Sakurai; M. Ikeda

    2003-01-01

    Objective. To examine if iron-deficient conditions modify body burden or health effects of cadmium among women in the general population in Japan.Methods. In 2002, 1,482 women aged 20 to 74 years in six prefectures in Japan provided informed consent to participate in this study. They offered peripheral blood and spot urine samples, and answered questionnaires on their social habits and

  7. Development and application of 16S rRNA-targeted probes for detection of iron- and manganese-oxidizing sheathed bacteria in environmental samples.

    PubMed Central

    Siering, P L; Ghiorse, W C

    1997-01-01

    Comparative sequence analysis of the 16S rRNA genes from several Leptothrix and Sphaerotilus strains led to the design of an oligonucleotide probe (PS-1) based on a sequence within the hypervariable region 1 specific for four Leptothrix strains and for one of the four Sphaerotilus natans strains examined. Another probe (PSP-6) was based on a sequence within the hypervariable region 2. PSP-6 was specific for one of the two evolutionary lineages previously described for Leptothrix spp. (P. L. Siering and W. C. Ghiorse, Int. J. Syst. Bacteriol. 46:173-182, 1996). Fluorescein-labeled oligonucleotide probes were synthesized, and their specificity for fluorescence in situ hybridization identification was confirmed by a laser scanning microscopy technique (W. C. Ghiorse, D. N. Miller, R. L. Sandoli, and P. L. Siering, Microsc. Res. Tech. 33:73-86, 1996) to compare whole-cell hybridizations of closely related bacteria. Probe specificity was also tested in dot blot against total RNA isolated from four Leptothrix strains, four Sphaerotilus strains, and 15 other members of the class Proteobacteria. When the probes were tested on samples from the Sapsucker Woods wetland habitat where Leptothrix spp. are thought to play a role in manganese and iron oxidation, positive signals were obtained from several sheathed filamentous bacteria including some that were morphologically similar to previously isolated strains of "Leptothrix discophora." Other unknown filamentous sheathed bacteria also gave strong positive signals. This work provides a foundation for future studies correlating the presence of members of the Leptothrix-Sphaerotilus group of sheathed bacteria with manganese and iron oxidation activity in habitats where biological iron and manganese oxidation are important environmental processes. PMID:9023942

  8. Oxidation of pyrite and iron sulfide by manganese dioxide in marine sediments

    NASA Astrophysics Data System (ADS)

    Schippers, A.; Jørgensen, B. B.

    2001-03-01

    Oxidation of pyrite (FeS 2) under anaerobic conditions in marine sediments is experimentally shown for the first time. In slurry experiments with 55FeS 2 and a MnO 2 rich marine sediment an oxidation of 55FeS 2 was detected which decreased with depth and decreasing concentration of MnO 2 in the sediment. FeS 2 and iron sulfide (FeS) were oxidized chemically at pH 8 by MnO 2 but not by nitrate or amorphic Fe(III) oxide. Elemental sulfur and sulfate were the only products of FeS oxidation, whereas FeS 2 was oxidized to a variety of sulfur compounds, mainly sulfate plus intermediates such as thiosulfate, trithionate, tetrathionate, and pentathionate. Thiosulfate was oxidized by MnO 2 to tetrathionate while other intermediates were oxidized to sulfate. The reaction products indicate that FeS 2 was oxidized via the "Thiosulfate-mechanism" and FeS via the "Polysulfide-mechanism" (Schippers and Sand, 1999). The processes are summarized by the overall equations: (1) FeS 2+7.5 MnO 2+11 H +?Fe(OH) 3+2 SO 42-+7.5 Mn 2++4 H 2O (2) FeS+1.5 MnO 2+3 H +?Fe(OH) 3+S O+1.5 Mn 2+ For FeS 2 oxidation the reaction rates related to the mineral surface area were 1.02 and 1.12 nmol m -2 s -1 for total dissolved S and total dissolved Fe, respectively. Since these values are in the same range as previously published rates for the oxidation of FeS 2 by Fe(III), and since Fe(III) is a well-known oxidant for FeS 2 even at circumneutral pH, Fe(III) is assumed also to be the oxidant for FeS and FeS 2 in the presence of MnO 2. At the iron sulfide surface, Fe(III) is reduced to Fe(II) which is reoxidized to Fe(III) by MnO 2. Thus, an Fe(II)/Fe(III) shuttle should transport electrons between the surfaces of the two solid compounds.

  9. A study of the kinetics and fate of zinc-65 and iron-59 mobilized from labeled ghosts by reticulocyte lysates of normal and cadmium-treated rabbits 

    E-print Network

    McAleese, Kathryn Noel

    1976-01-01

    A STUDY OF THE KINETICS AND FATE OF ZINC ? 65 AND IRON-59 MOBILIZED FROM LABELED GHOSTS BY RETICULOCYTE LYSATES OF NORMAL AND CADMIUM-TREATED RABBITS A Thesis by KATHRYN NOEL McALEESE Submitted to the Graduate College of Texas ASM University... in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE December 1976 Major Subject: Biochemistry A STUDY OF THE KINETICS AND FATE OF ZINC-65 AND IRON-59 MOBILIZED FROM LABELED GHOSTS BY RETICULOCYTE LYSATES OF NORMAL AND CAIRIUM...

  10. Evolution of novel bioresorbable iron-manganese implant surfaces and their degradation behaviors in vitro.

    PubMed

    Heiden, Michael; Walker, Emily; Nauman, Eric; Stanciu, Lia

    2015-01-01

    The purpose of this study is to advance understanding of surface degradation kinetics for Fe-Mn bioresorbable alloys (specifically Fe-20%Mn) and target degradable fracture fixation implants for hard tissues. This study addresses how arc melted Fe-20%Mn discs degrade in a static, osteogenic medium for up to a 3 month time span. Degradation behavior of these bulk alloys was investigated using both mass loss tests for measuring long-term corrosion rates and potentiostatic tests for following the instantaneous rate of degradation. It was discovered that cold-rolling Fe-20%Mn to 77% cold work (CW) suppressed the instantaneous corrosion rate compared with the cast structure. It was also found that an unstable iron-rich oxide layer forms on the entire surface of these bulk samples and the act of machining the bulk metal into a defined shape may affect the morphology of the oxide layer on the outer edge of the samples during degradation. The mechanisms behind the surface evolution of these potential orthopedic implants are investigated in detail. PMID:24616416

  11. X-ray fluorescence analysis of iron and manganese distribution in primary dopaminergic neurons

    PubMed Central

    Du?i?, Tanja; Barski, Elisabeth; Salome, Murielle; Koch, Jan C; Bähr, Mathias; Lingor, Paul

    2013-01-01

    Transition metals have been suggested to play a pivotal role in the pathogenesis of Parkinson's disease. X-ray microscopy combined with a cryogenic setup is a powerful method for elemental imaging in low concentrations and high resolution in intact cells, eliminating the need for fixation and sectioning of the specimen. Here, we performed an elemental distribution analysis in cultured primary midbrain neurons with a step size in the order of 300 nm and ? 0.1 ppm sensitivity under cryo conditions by using X-ray fluorescence microscopy. We report the elemental mappings on the subcellular level in primary mouse dopaminergic (DAergic) and non-DAergic neurons after treatment with transition metals. Application of Fe2+ resulted in largely extracellular accumulation of iron without preference for the neuronal transmitter subtype. A quantification of different Fe oxidation states was performed using X-ray absorption near edge structure analysis. After treatment with Mn2+, a cytoplasmic/paranuclear localization of Mn was observed preferentially in DAergic neurons, while no prominent signal was detectable after Mn3+ treatment. Immunocytochemical analysis correlated the preferential Mn uptake to increased expression of voltage-gated calcium channels in DAergic neurons. We discuss the implications of this differential elemental distribution for the selective vulnerability of DAergic neurons and Parkinson's disease pathogenesis. PMID:23106162

  12. A photo-oxidation procedure using UV radiation/H 2O 2 for decomposition of wine samples — Determination of iron and manganese content by flame atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    dos Santos, Walter N. L.; Brandão, Geovani C.; Portugal, Lindomar A.; David, Jorge M.; Ferreira, Sérgio L. C.

    2009-06-01

    This paper proposes the use of photo-oxidation with UV radiation/H 2O 2 as sample pretreatment for the determination of iron and manganese in wines by flame atomic absorption spectrometry (FAAS). The optimization involved the study of the following variables: pH and concentration of buffer solution, concentrated hydrogen peroxide volume and irradiation time. The evaluation of sample degradation was monitored by measuring the absorbance at the maximum wavelength of red wine (530 nm). Using the experimental conditions established during the optimization (irradiation time of 30 min, oxidant volume of 2.5 mL, pH 10, and a buffer concentration of 0.15 mol L - 1 ), this procedure allows the determination of iron and manganese with limits of detection of 30 and 22 ?g L - 1 , respectively, for a 5 mL volume of digested sample. The precision levels, expressed as relative standard deviation (RSD), were 2.8% and 0.65% for iron and 2.7% and 0.54% for manganese for concentrations of 0.5 and 2.0 mg L - 1 , respectively. Addition/recovery tests for evaluation of the accuracy were in the ranges of 90%-111% and 95%-107% for iron and manganese, respectively. This digestion procedure has been applied for the determination of iron and manganese in six wine samples. The concentrations varied from 1.58 to 2.77 mg L - 1 for iron and from 1.30 to 1.91 mg L - 1 for manganese. The results were compared with those obtained by an acid digestion procedure and determination of the elements by FAAS. There was no significant difference between the results obtained by the two methods based on a paired t-test (at 95% confidence level).

  13. Manganese, the stress reliever.

    PubMed

    Latour, J-M

    2015-01-01

    Convergent evidence has emerged over the past decade to highlight the role of manganese as a key player in the defenses that many organisms are building to fight oxidative stress. For redox processes replacing iron by manganese requires adaptation at different levels. The aim of this perspective is to summarize recent important observations and to analyze the implications of the present knowledge for resolving future issues. PMID:25434324

  14. The precipitation of aluminum, iron and manganese at the junction of Deer Creek with the Snake River in Summit County, Colorado

    USGS Publications Warehouse

    Theobald, P.K., Jr.; Lakin, H.W.; Hawkins, D.B.

    1963-01-01

    The oxidation of disseminated pyrite in relatively acid schists and gneisses of the Snake River drainage basin provides abundant iron sulfate and sulfuric acid to ground and surface water. This acid water dissolves large quantities of many elements, particularly aluminum and surprisingly large quantities of elements, such as magnesium and zinc, not expected to be abundant in the drainage basin. The adjoining drainage to the west, Deer Creek, is underlain by basic rocks, from which the water inherits a high pH. Despite the presence of base- and precious- metal veins in the drainage basin of Deer Creek, it carries less metal than the Snake River. The principal precipitate on the bed of the Snake River is hydrated iron oxide with small quantities of the other metals. In Deer Creek manganese oxide is precipitated with iron oxide and large quantities of other metals are carried down with this precipitate. Below the junction of these streams the pH stabilizes at a near-neutral value. Iron is removed from the Snake River water at the junction, and aluminum is precipitated for some distance downstream. The aluminum precipitate carries down other metals in concentrations slightly less than that in the manganese precipitate on Deer Creek. The natural processes observed in this junction if carried to a larger scale could provide the mechanism described by Ansheles (1927) for the formation of bauxite. In the environment described, geochemical exploration by either water or stream sediment techniques is difficult because of (1) the extreme pH differential between the streams above their junction and (2) the difference in the precipitates formed on the streambeds. ?? 1963.

  15. Manganese(II), iron(II), cobalt(II), and copper(II) complexes of an extended inherently chiral tris-bipyridyl cage

    PubMed Central

    Perkins, David F.; Lindoy, Leonard F.; McAuley, Alexander; Meehan, George V.; Turner, Peter

    2006-01-01

    Manganese(II), iron(II), cobalt(II), and copper(II) derivatives of two inherently chiral, Tris(bipyridyl) cages (L and L?) of type [ML]-(PF6)2(solvent)n and [FeL?](ClO4)2 are reported, where L is the hexa-tertiary butyl-substituted derivative of L?. These products were obtained by using the free cage and metal template procedures; the latter involved the reductive amination of the respective Tris-dialdehyde precursor complexes of iron(II), cobalt(II), or nickel(II). Electrochemical, EPR, and NMR studies have been used to probe the nature of the individual complexes. X-ray structures of the manganese(II), iron(II), and copper(II) complexes of L and the iron(II) complex of L? are presented; these are compared with the previously reported structures of the corresponding nickel(II) complex and metal-free cage (L). In each complex the metal cation occupies the cage's central cavity and is coordinated to six nitrogens from the three bipyridyl groups. The cations [MnL]2+ and [FeL]2+ are isostructural but both exhibit a different arrangement of the bound cage to that observed in the corresponding nickel(II) and copper(II) complexes. The latter have an exo-exo arrangement of the bridgehead nitrogen lone pairs, with the metal inducing a triple helical twist that extends ?22 Å along the axial length of each complex. In contrast, [MnL]2+ and [FeL]2+ have their terminal nitrogen lone pairs directed endo, causing a significant change in the configuration of the bound ligand. In [FeL?]2+, the cage has both bridgehead nitrogen lone pairs orientated exo. Semiempirical calculations indicate that the observed endo-endo and exo-exo arrangements are of comparable energy. PMID:16407129

  16. Long-term removal and retention of iron and manganese from acidic mine drainage by wetlands. Volume 1. Methods, results, and appendices. Final report, July 1987-January 1990

    SciTech Connect

    Brooks, R.P.; Unz, R.F.; Davis, L.K.; Tarutis, W.J.; Yanchunas, J.

    1990-01-01

    A promising low-technology solution for treating acidic mine drainage (AMD) emanating from coal mined lands involves the use of constructed wetlands. The research was directed at addressing questions about retention mechanisms for the long-term storage of iron and manganese in constructed wetlands dominated by broad-leaved cattails (Typha latifolia). Three sites in central Pennsylvania spanning the range of water chemistry parameters found in AMD were investigated. When the AMD was circumneutral, and metal loadings were low, 79% of the iron, and 48% of the manganese were retained on average. In the highly acidic site (pH approx. = 3), < 10% of the metal loadings were retained. The primary retention mechanism appears to be the formation of metal oxides in the aerobic zones of the sediments. Although most microbial isolates extracted from sediment cores originated in the aerobic portions of the sediments, there was no evidence that they were transforming metals. When AMD is circumneutral and metal loadings are low, constructed wetlands can be an effective approach to treating mine drainage. At sites with highly acidic waters and high metal loadings, the use of constructed wetlands to treat AMD may be ineffectual, and should be implemented with caution.

  17. Effect of manganese and iron at a neutral and acidic pH on the hematology of the banded Tilapia (Tilapia sparrmanii)

    SciTech Connect

    Wepener, V.; Van Vuren, J.H.J.; Du Preez, H.H. [Rand Afrikaans Univ., Johannesburg (South Africa)

    1992-10-01

    The pollution of natural water bodies is a common phenomenon in developing countries. Increases in population densities lead to increased mining and industrial activities in the area. With the establishment of gold and coal mines in South Africa, several industrial zones were created to support the mining industry. Many of these industries consist of heavy metal processing factories. Over the years pollution from the mines has led to acidification of the streams and lakes in the Transvaal. It was also found that high concentrations of heavy metals occurred in the water, sediments, plants and fish tissue in the affected water systems. Of all the heavy metals, iron and manganese were found in the highest concentrations. In order to determine the subtle, non-lethal effects induced by sublethal concentrations of heavy metals on the physiology of fish, it is necessary to monitor certain clinical parameters. The use of hematological methods as indicators of sublethal stress can supply valuable information concerning the physiological reactions of fish in a changing environment. The reason for this is the close association between the circulatory system of the fish and the external environment. The objective of the present paper was to evaluate the effects of manganese and iron at a neutral and acidic pH on the hematology of Tilapia sparrmanii. 19 refs., 2 figs.

  18. Reducing effect of ingesting tannic acid on the absorption of iron, but not of zinc, copper and manganese by rats.

    PubMed

    Afsana, Kaosar; Shiga, Kazuki; Ishizuka, Satoshi; Hara, Hiroshi

    2004-03-01

    Interest in the beneficial effects of polyphenols, including tannic acid (TA), is increasing, although, these compounds also have adverse effects; for example, on the absorption of iron (Fe), and possibly other trace minerals. We examined the effect of a graded dose of TA on the absorption of Fe and compared with that of zinc (Zn), copper (Cu) and manganese (Mn) in rats. We also investigated the effect of TA on cecal fermentation which plays a role in absorption. In Experiment 1, to set the optimum dose of Fe, male Sprague-Dawley rats (weighing 70-90 g) after acclimatization were fed with different levels of dietary Fe (5, 10, 20, 30 and 35 mg/kg). We observed that the hematocrit (Ht), serum Fe concentration and transferrin saturation (%) were each reduced in those rats fed less than 20 mg/kg Fe in a dose-dependent manner. In Experiment 2, the rats were fed with test diets containing the minimum required level of Fe, 30 mg/kg diet, with (5, 10, 15 and 20 g/kg diet) or without TA for a period of three weeks. Feeding a diet containing more than 10 g TA/kg diet, but not 5 g TA/kg diet, reduced the hemoglobin concentration (Hb), Ht and serum Fe concentration due to decreased Fe absorption. In contrast, the Zn, Cu and Mn absorption was not affected by TA feeding. It is also demonstrated that liver Fe, but not the Zn, Cu and Mn contents, were lower in the TA groups than in the TA-free control group. Feeding TA slightly decreased the pH value of the cecal contents with an increase in the major short-chain fatty acid pool. About 15% of the ingested TA were recovered in the feces of each TA-fed group. Our results demonstrate that more than 10 g TA/kg diet induced anemia by reducing the Fe absorption, although there was no effect on the absorption of other important trace minerals. Our findings suggest that the usual intake of polyphenols is relatively safe, but that a high intake by supplementation or by dietary habit of tannin affects only the Fe level. PMID:15056891

  19. Catalytic oxidation of NO with O2 over FeMnOx/TiO2: Effect of iron and manganese oxides loading sequences and the catalytic mechanism study

    NASA Astrophysics Data System (ADS)

    Zhang, Mengying; Li, Caiting; Qu, Long; Fu, Mengfan; Zeng, Guangming; Fan, Chunzhen; Ma, Jinfeng; Zhan, Fuman

    2014-05-01

    FeMnOx/TiO2 with different iron and manganese oxides adding orders were prepared through isovolumetric impregnation and tested for catalytic oxidation of NO with O2. It was found that the sample obtained from one-step impregnation method had better catalytic activity. The excellent activity was attributed to higher surface area, lower crystalline of manganese oxides, abundant Mn3+, Fe3+ and chemisorbed oxygen species on the surface. Furthermore, effects of loading sequences on FeMnOx/TiO2 catalysts were investigated. The study showed that Fe and Mn would affect each other and change the surface physicochemical properties of FeMnOx/TiO2 when they were loaded step-by-step. In addition, the inhibiting effect of H2O on catalytic activity was reversible while the conversion of NO recovered to 40% when SO2 was cut off. XPS analysis between used and fresh catalysts revealed the electron transfer between Fen+ and Mnn+ ions in FeMnOx/TiO2. Possible reaction mechanism was put forward by comprehensive analysis of XPS and FT-IR results.

  20. Manganese recycling in the United States in 1998

    USGS Publications Warehouse

    Jones, Thomas S.

    2001-01-01

    This report describes the flow and processing of manganese within the U.S. economy in 1998 with emphasis on the extent to which manganese is recycled. Manganese was used mostly as an alloying agent in alloys in which it was a minor component. Manganese was recycled mostly within scrap of iron and steel. A small amount was recycled within aluminum used beverage cans. Very little manganese was recycled from materials being recovered specifically for their manganese content. For the United States in 1998, 218,000 metric tons of manganese was estimated to have been recycled from old scrap, of which 96% was from iron and steel scrap. Efficiency of recycling was estimated as 53% and recycling rate as 37%. Metallurgical loss of manganese was estimated to be about 1.7 times that recycled. This loss was mostly into slags from iron and steel production, from which recovery of manganese has yet to be shown economically feasible.

  1. Effects of iron, zinc, calcium, and vitamins on the activity and contents of human placental copper/zinc and manganese superoxide dismutases.

    PubMed

    Hunaiti, A A; Saleh, M S

    1996-09-01

    One hundred seventy-nine pregnant women, ages 15-45 yr, were divided into three groups. Group A was orally given one spansule per day containing 150 mg dried ferrous sulfate, 61.8 mg zinc sulfate, and 500 micrograms folic acid, starting from the first 4 wk of pregnancy and ending at the day of delivery. Similarly, group B was given one tablet containing 625 mg calcium carbonate, 1000 mg vitamin C, 300 IU Vitamin D, 1350 mg citric acid, and 15 mg Vitamin B6. Group C was without any supplements and served as a control. Mothers who received iron/zinc supplements (group A) during pregnancy had significantly higher copper/zinc superoxide dismutase activity in their placentae than calcium/vitamin-supplemented mothers (group B) or unsupplemented mothers (group C). The enzyme activity increased with age of the mothers from 15 to 40 yr, then decreased after in both supplemented groups, whereas this increase and decrease occurred at early age in the unsupplemented group. Immunochemical quantitation of the enzyme contents showed no significant difference between the supplemented and unsupplemented groups, suggesting that the observed increase in the enzyme activity might arise from posttranslational processing of the enzyme. The placental manganese superoxide dismutase activity and contents, however, were similar in the supplemented groups, whereas they were slightly higher in the unsupplemented group; the overall superoxide dismutase-like activities in the placentae were the highest in iron-zinc supplemented group and the lowest in the unsupplemented group. PMID:8909696

  2. Concentrations of strontium, barium, cadmium, copper, zinc, manganese, chromium, antimony, selenium, and lead in the liver and kidneys of dogs according to age, gender, and the occurrence of chronic kidney disease

    PubMed Central

    Mainzer, Barbara; Lahrssen-Wiederholt, Monika; Schafft, Helmut; Palavinskas, Richard; Breithaupt, Angele; Zentek, Jürgen

    2015-01-01

    This study was conducted to measure the concentrations of strontium (Sr), barium (Ba), cadmium (Cd), copper (Cu), zinc (Zn), manganese (Mn), chromium (Cr), antimony (Sb), selenium (Se), and lead (Pb) in canine liver, renal cortex, and renal medulla, and the association of these concentrations with age, gender, and occurrence of chronic kidney disease (CKD). Tissues from 50 dogs were analyzed using inductively coupled plasma mass spectrometry. Cu, Zn, and Mn levels were highest in the liver followed by the renal cortex and renal medulla. The highest Sr, Cd, and Se concentrations were measured in the renal cortex while lower levels were found in the renal medulla and liver. Female dogs had higher tissue concentrations of Sr (liver and renal medulla), Cd (liver), Zn (liver and renal cortex), Cr (liver, renal cortex, and renal medulla), and Pb (liver) than male animals. Except for Mn and Sb, age-dependent variations were observed for all element concentrations in the canine tissues. Hepatic Cd and Cr concentrations were higher in dogs with CKD. In conclusion, the present results provide new knowledge about the storage of specific elements in canine liver and kidneys, and can be considered important reference data for diagnostic methods and further investigations. PMID:25234328

  3. Influence of essential elements on manganese intoxication

    SciTech Connect

    Khandelwal, S.; Ashquin, M.; Tandon, S.K.

    1984-01-01

    With a view to explore the influence of essential metals in manganese intoxication, the effect of calcium, iron or zinc supplementation on the uptake of manganese and on the activity of manganese sensitive enzymes, succinic dehydrogenase and cytochrome oxidase in brain and liver of rat was investigated. The choice of the two mitochondrial enzymes was based on the fact that the mitochondria are the chief site of manganese accumulation and their activity in brain, liver and blood of rats is significantly influenced by manganese.

  4. Fractionation and solubility of cadmium in paddy soils amended with porous hydrated calcium silicate.

    PubMed

    Zhao, Xiu-Lan; Masaihiko, Saigusa

    2007-01-01

    Previous studies have shown that porous hydrated calcium silicate (PS) is very effective in decreasing cadmium (Cd) content in brown rice. However, it is unclear whether the PS influences cadmium transformation in soil. The present study examined the effect of PS on pH, cadmium transformation and cadmium solubility in Andosol and Alluvial soil, and also compared its effects with CaCO3, acidic porous hydrated calcium silicate (APS) and silica gel. Soil cadmium was operationally fractionationed into exchangeable (Exch), bound to carbonates (Carb), bound to iron and manganese oxides (FeMnO(x)), bound to organic matters (OM) and residual (Res) fraction. Application of PS and CaCO3 at hig rates enhanced soil pH, while APS and silica gel did not obviously change soil pH. PS and CaCO3 also increased the FeMnO(x)-Cd in Andosol and Carb-Cd in Alluvial soil, thus reducing the Exch-Cd in the tested soils. However, PS was less effective than CaCO3 at the same application rate. Cadmium fractions in the two soils were not changed by the treatments of APS and silica gel. There were no obvious differences in the solubility of cadmium in soils treated with PS, APS, silica gel and CaCO3 except Andosol treated 2.0% CaCO3 at the same pH of soil-CaCl2 suspensions. These findings suggested that the decrease of cadmium availability in soil was mainly attributed to the increase of soil pH caused by PS. PMID:17918598

  5. Cobalt, manganese, and iron near the Hawaiian Islands: A potential concentrating mechanism for cobalt within a cyclonic eddy and implications for the hybrid-type trace metals

    NASA Astrophysics Data System (ADS)

    Noble, Abigail E.; Saito, Mak A.; Maiti, Kanchan; Benitez-Nelson, Claudia R.

    2008-05-01

    The vertical distributions of cobalt, iron, and manganese in the water column were studied during the E-Flux Program (E-Flux II and III), which focused on the biogeochemistry of cold-core cyclonic eddies that form in the lee of the Hawaiian Islands. During E-Flux II (January 2005) and E-Flux III (March 2005), 17 stations were sampled for cobalt ( n=147), all of which demonstrated nutrient-like depletion in surface waters. During E-Flux III, two depth profiles collected from within a mesoscale cold-core eddy, Cyclone Opal, revealed small distinct maxima in cobalt at ˜100 m depth and a larger inventory of cobalt within the eddy. We hypothesize that this was due to a cobalt concentrating effect within the eddy, where upwelled cobalt was subsequently associated with sinking particulate organic carbon (POC) via biological activity and was released at a depth coincident with nearly complete POC remineralization [Benitez-Nelson, C., Bidigare, R.R., Dickey, T.D., Landry, M.R., Leonard, C.L., Brown, S.L., Nencioli, F., Rii, Y.M., Maiti, K., Becker, J.W., Bibby, T.S., Black, W., Cai, W.J., Carlson, C.A., Chen, F., Kuwahara, V.S., Mahaffey, C., McAndrew, P.M., Quay, P.D., Rappe, M.S., Selph, K.E., Simmons, M.P., Yang, E.J., 2007. Mesoscale eddies drive increased silica export in the subtropical Pacific Ocean. Science 316, 1017-1020]. There is also evidence for the formation of a correlation between cobalt and soluble reactive phosphorus during E-Flux III relative to the E-Flux II cruise that we suggest is due to increased productivity, implying a minimum threshold of primary production below which cobalt-phosphate coupling does not occur. Dissolved iron was measured in E-Flux II and found in somewhat elevated concentrations (˜0.5 nM) in surface waters relative to the iron depleted waters of the surrounding Pacific [Fitzwater, S.E., Coale, K.H., Gordon, M.R., Johnson, K.S., Ondrusek, M.E., 1996. Iron deficiency and phytoplankton growth in the equatorial Pacific. Deep-Sea Research II 43 (4-6), 995-1015], possibly due to island effects associated with the iron-rich volcanic soil from the Hawaiian Islands and/or anthropogenic inputs. Distinct depth maxima in total dissolved cobalt were observed at 400-600 m depth, suggestive of the release of metals from the shelf area of comparable depth that surrounds these islands.

  6. Investigation of the effects of cadmium by micro analytical methods on Lycopersicon esculentum Mill. roots.

    PubMed

    Colak, G; Baykul, M C; Gürler, R; Catak, E; Caner, N

    2014-09-01

    The interactions between cadmium stress and plant nutritional elements have been investigated on complete plant or at the level of organs. This study was undertaken to contribute to the exploration of the physiological basis of cadmium phytotoxicity. We examined the changes in the nutritional element compositions of the root epidermal cells of the seedlings of Lycopersicon esculentum Mill. at the initial growth stages that is known as the most sensitive stage to the stress. Effects of cadmium stress on the seedlings of Lycopersicon esculentum Mill. were examined by EDX (Energy Dispersive X-Ray Microanalysis) assay performed with using low vacuum (? 24 Pascal) Scanning Electron Microscopy. In the analysis performed at the level of root epidermal cells, some of the macro- and micronutrient contents of the cells (carbon, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, copper, and zinc levels) were found to change when the applying toxic concentrations of cadmium. There was no change in the manganese and sodium content of the epidermal cells. It was concluded that the changes in nutritional element composition of the cells can be considered as an effective parameter in explaining the physiological mechanisms of cadmium-induced growth inhibition. PMID:25194735

  7. A first-principles study aided with Monte Carlo simulations of carbon doped iron-manganese alloys

    NASA Astrophysics Data System (ADS)

    Comtesse, D.; Herper, H. C.; Hucht, A.; Entel, P.

    2012-10-01

    We have investigated the complex magnetic properties of Fe1- x Mn x C y alloys by using an iterative combination of ab initio calculations and Monte Carlo simulations. The latter gives insight into finite temperature magnetism and allows to determine the critical temperature of magnetic phase transitions. We restrict the investigation to ordered systems with 25, 50 and 75% manganese and study the influence of carbon at octahedral interstitial sites on the magnetic properties. The combination of ab initio calculations with Monte Carlo simulations turns out to be a powerful tool to determine the complex magnetic structures, which originate from the competition of ferro- and antiferromagnetic interactions in the FeMn alloys.

  8. Manganese neurotoxicity.

    PubMed

    Dobson, Allison W; Erikson, Keith M; Aschner, Michael

    2004-03-01

    Manganese is an essential trace element and it is required for many ubiquitous enzymatic reactions. While manganese deficiency rarely occurs in humans, manganese toxicity is known to occur in certain occupational settings through inhalation of manganese-containing dust. The brain is particularly susceptible to this excess manganese, and accumulation there can cause a neurodegenerative disorder known as manganism. Characteristics of this disease are described as Parkinson-like symptoms. The similarities between the two disorders can be partially explained by the fact that the basal ganglia accumulate most of the excess manganese compared with other brain regions in manganism, and dysfunction in the basal ganglia is also the etiology of Parkinson's disease. It has been proposed that populations already at heightened risk for neurodegeneration may also be more susceptible to manganese neurotoxicity, which highlights the importance of investigating the human health effects of using the controversial compound, methylcyclopentadienyl manganese tricarbonyl (MMT), in gasoline to increase octane. The mechanisms by which increased manganese levels can cause neuronal dysfunction and death are yet to be elucidated. However, oxidative stress generated through mitochondrial perturbation may be a key event in the demise of the affected central nervous system cells. Our studies with primary astrocyte cultures have revealed that they are a critical component in the battery of defenses against manganese-induced neurotoxicity. Additionally, evidence for the role of oxidative stress in the progression of manganism is reviewed here. PMID:15105259

  9. Extracellular Norepinephrine, Norepinephrine Receptor and Transporter Protein and mRNA Levels Are Differentially Altered in the Developing Rat Brain Due to Dietary Iron Deficiency and Manganese Exposure

    PubMed Central

    Anderson, Joel G.; Fordahl, Steven C.; Cooney, Paula T.; Weaver, Tara L.; Colyer, Christa L.; Erikson, Keith M.

    2009-01-01

    Manganese (Mn) is an essential trace element, but overexposure is characterized by Parkinson’s like symptoms in extreme cases. Previous studies have shown Mn accumulation is exacerbated by dietary iron deficiency (ID) and disturbances in norepinephrine (NE) have been reported. Because behaviors associated with Mn neurotoxicity are complex, the goal of this study was to examine the effects of Mn exposure and ID-associated Mn accumulation on NE uptake in synaptosomes, extracellular NE concentrations, and expression of NE transport and receptor proteins. Sprague-Dawley rats were assigned to four dietary groups: control (CN; 35 mg Fe/kg diet), iron-deficient (ID; 6 mg Fe/kg diet), CN with Mn exposure (via the drinking water; 1 g Mn/L) (CNMn), and ID with Mn (IDMn). 3H-NE uptake decreased significantly (R=?0.753, p=0.001) with increased Mn concentration in the locus coeruleus, while decreased Fe was associated with decreased uptake of 3H-NE in the caudate putamen (R=0.436, p=0.033) and locus coeruleus (R=0.86; p<0.001). Extracellular concentrations of NE in the caudate putamen were significantly decreased in response to Mn exposure and ID (p<0.001). A diverse response of Mn exposure and ID was observed on mRNA and protein expression of NE transporter (NET) and ?2 adrenergic receptor. For example, elevated brain Mn and decreased Fe caused an approximate 50% decrease in NET and ?2 adrenergic receptor protein expression in several brain regions, with reductions in mRNA expression also observed. These data suggest that Mn exposure results in a decrease in NE uptake and extracellular NE concentrations via altered expression of transport and receptor proteins. PMID:19481535

  10. MANGANESE TOURMALINES

    Microsoft Academic Search

    M. N. Slivko

    1961-01-01

    The role of manganese in the chemical composition and coloring of tourmaline is discussed. It is shown that manganese tourmaline-tsilaisite is similar to tourmaline-elbaite in composition and condition formation. The miscibility in the sherlite-elbaite-tsilaisite system is complete, but in the sherlite-dravite-tsilaisite system there is a gap between the dravite and tsilaisite, similar to the relationship between dravite and elbaite.Manganese may

  11. Iron

    MedlinePLUS

    Iron is a mineral that our bodies need for many functions. For example, iron is part of hemoglobin, a protein which carries ... It helps our muscles store and use oxygen. Iron is also part of many other proteins and ...

  12. Application of Zeeman graphite furnace atomic absorption spectrometry with high-frequency modulation polarization for the direct determination of aluminum, beryllium, cadmium, chromium, mercury, manganese, nickel, lead, and thallium in human blood.

    PubMed

    Ivanenko, Natalya B; Solovyev, Nikolay D; Ivanenko, Anatoly A; Ganeev, Alexander A

    2012-10-01

    Determination of aluminum (Al), beryllium (Be), cadmium (Cd), chromium (Cr), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), and thallium (Tl) concentrations in human blood using high-frequency modulation polarization Zeeman graphite furnace atomic absorption spectrometry (GFAAS) was performed. No sample digestion was used in the current study. Blood samples were diluted with deionized water or 0.1 % (m/v) Triton X-100 solution for Tl. Dilution factors ranged from 1/5 per volume for Be and Tl to 1/20 per volume for Cd and Pb. For Tl, Cd, and Hg, noble metals (gold, platinum, rhodium, etc.) were applied as surface modifiers. To mitigate chloride interference, 2 % (m/v) solution of NH(4)NO(3) was used as matrix modifier for Tl and Ni assessment. The use of Pd(NO(3))(2) as oxidative modifier was necessary for blood Hg and Tl measurement. Validation of the methods was performed by analyzing two-level reference material Seronorm. The precision of the designed methods as relative SD was between 4 and 12 % (middle of a dynamic range) depending on the element. For additional validation, spiked blood samples were analyzed. Limits of detection (LoDs, 3?, n = 10) for undiluted blood samples were 2.0 ?g L(-1) for Al, 0.08 ?g L(-1) for Be, 0.10 ?g L(-1) for Cd, 2.2 ?g L(-1) for Cr, 7 ?g L(-1) for Hg, 0.4 ?g L(-1) for Mn, 2.3 ?g L(-1) for Ni, 3.4 ?g L(-1) for Pb, and 0.5 ?g L(-1) for Tl. The LoDs achieved allowed determination of Al, Cd, Cr, Mn, Ni, and Pb at both toxic and background levels. Be, Hg, and Tl could be reliably measured at toxic levels only. The methods developed are used for clinical diagnostics and biological monitoring of work-related exposure. PMID:22868581

  13. Manganese-Induced Hydroxyl Radical Formation in Rat Striatum Is Not Attenuated by Dopamine Depletion or Iron Chelation in Vivo

    Microsoft Academic Search

    W. N. Sloot; J. Korf; J. F. Koster; L. E. A. de Wit; J. B. P. Gramsbergen

    1996-01-01

    The present studies were aimed at investigating the possible roles of dopamine (DA) and iron in production of hydroxyl radicals (·OH) in rat striatum after Mn2+intoxication. For this purpose, DA depletions were assessed concomitant within vivo2,3- and 2,5-dihydroxybenzoic acid (DHBA) formation from the reaction of salicylate with·OH, of which 2,3-DHBA is a nonenzymatic adduct. Following intrastriatal Mn2+injection, marked 2,3-DHBA increases

  14. Method for selective recovery of cadmium from cadmium-bearing waste

    Microsoft Academic Search

    H. Reinhardt; H. D. Ottertun; J. H. A. Rydberg

    1977-01-01

    A method for the selective recovery of cadmium, nickel and cobalt from a nickel--cadmium battery waste comprises the following steps: (A) leaching the waste with an ammoniacal carbonate solution to form an aqueous ammoniacal carbonate solution containing cadmium, nickel and cobalt (II) ammine complexes and a leaching residue--any iron in the waste is in the leaching residue; (B) adding air

  15. The magnetism of metallic manganese alloys

    SciTech Connect

    Holden, T.M. (Atomic Energy of Canada Ltd., Chalk River, ON (Canada)); Mikke, K. (Institute of Atomic Energy, Otwock-Swierk (Poland)); Fawcett, E. (Toronto Univ., ON (Canada)); Fernandez-Baca, J.A. (Oak Ridge National Lab., TN (United States))

    1992-01-01

    The magnetic excitations in antiferromagnetic manganese-copper and manganese-iron alloys are characterized by high spin-wave velocities, and energy gap at long wavelengths and wavelength dependent damping. There are strong elastic constant anomalies above T[sub N] as well as magnetoelastic distortions below T[sub N]. The theoretical explanation of these effects is reviewed.

  16. The magnetism of metallic manganese alloys

    SciTech Connect

    Holden, T.M. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada); Mikke, K. [Institute of Atomic Energy, Otwock-Swierk (Poland); Fawcett, E. [Toronto Univ., ON (Canada); Fernandez-Baca, J.A. [Oak Ridge National Lab., TN (United States)

    1992-12-31

    The magnetic excitations in antiferromagnetic manganese-copper and manganese-iron alloys are characterized by high spin-wave velocities, and energy gap at long wavelengths and wavelength dependent damping. There are strong elastic constant anomalies above T{sub N} as well as magnetoelastic distortions below T{sub N}. The theoretical explanation of these effects is reviewed.

  17. Transformation of triclosan to 2,8-dichlorodibenzo-p-dioxin by iron and manganese oxides under near dry conditions.

    PubMed

    Ding, Jiafeng; Su, Mian; Wu, Cuiwei; Lin, Kunde

    2015-08-01

    Triclosan (TCS) is a broad-spectrum antibacterial agent widely used in household and personal care products and is frequently detected in the environment. Previous studies have shown that TCS could be converted to the more toxic compound 2,8-dichlorodibenzo-p-dioxins (2,8-DCDD) in photochemical reactions and incineration processes. In this study, we demonstrated the formation of 2,8-DCDD from the oxidation of TCS by ?-FeOOH and a natural manganese oxides (MnOx) sand. Experiments at room temperature and under near dry conditions showed that Fe and Mn oxides readily catalyzed the conversion of TCS to 2,8-DCDD and other products. Approximately 5.5% of TCS was transformed to 2,8-DCDD by ?-FeOOH in 45d and a higher conversion percentage (6.7%) was observed for MnOx sand in 16d. However, the presence of water in the samples significantly inhibited the formation of 2,8-DCDD. Besides 2,8-DCDD, 2,4-dichlorphenol (2,4-DCP), 4-chlorobenzene-1,2-diol, 2-chloro-5-(2,4-dichlorophenoxy)benzene-1,4-diol, and 2-chloro-5-(2,4-dichlorophenoxy)-1,4-benzoquinone were identified in the reactions. The possible pathways for the formation of reaction products were proposed. This study suggests that Fe and Mn oxides-mediated transformation of TCS under near dry conditions might be another potential pathway for the formation of 2,8-DCDD in the natural environment. PMID:25880455

  18. Arabidopsis Thaliana CARBOXYL-TERMINAL DOMAIN PHOSPHATASE-Like1 (CPL1) Mediates Responses to Iron Deficiency and Cadmium Toxicity 

    E-print Network

    Aksoy, Emre

    2014-04-24

    The expression of genes that control iron (Fe) uptake and distribution (i.e., Fe utilization- related genes) is under a strict regulation. Fe deficiency strongly induces Fe utilization- related gene expression; however, little is known about...

  19. Manganese (II) induces chemical hypoxia by inhibiting HIF-prolyl hydroxylase: Implication in manganese-induced pulmonary inflammation

    SciTech Connect

    Han, Jeongoh [Laboratory of Biomedicinal Chemistry, College of Pharmacy, Pusan National University, Busan, 609-735 (Korea, Republic of); Lee, Jong-Suk [Laboratory of Physiology, College of Pharmacy, Yeungnam University, Gyeongsan (Korea, Republic of); Choi, Daekyu; Lee, Youna; Hong, Sungchae; Choi, Jungyun; Han, Songyi [Laboratory of Biomedicinal Chemistry, College of Pharmacy, Pusan National University, Busan, 609-735 (Korea, Republic of); Ko, Yujin; Kim, Jung-Ae [Laboratory of Physiology, College of Pharmacy, Yeungnam University, Gyeongsan (Korea, Republic of); Mi Kim, Young [Medicinal Chemistry, College of Pharmacy, Pusan National University, Busan (Korea, Republic of); Jung, Yunjin [Laboratory of Biomedicinal Chemistry, College of Pharmacy, Pusan National University, Busan, 609-735 (Korea, Republic of)], E-mail: jungy@pusan.ac.kr

    2009-03-15

    Manganese (II), a transition metal, causes pulmonary inflammation upon environmental or occupational inhalation in excess. We investigated a potential molecular mechanism underlying manganese-induced pulmonary inflammation. Manganese (II) delayed HIF-1{alpha} protein disappearance, which occurred by inhibiting HIF-prolyl hydroxylase (HPH), the key enzyme for HIF-1{alpha} hydroxylation and subsequent von Hippel-Lindau(VHL)-dependent HIF-1{alpha} degradation. HPH inhibition by manganese (II) was neutralized significantly by elevated dose of iron. Consistent with this, the induction of cellular HIF-1{alpha} protein by manganese (II) was abolished by pretreatment with iron. Manganese (II) induced the HIF-1 target gene involved in pulmonary inflammation, vascular endothelial growth factor (VEGF), in lung carcinoma cell lines. The induction of VEGF was dependent on HIF-1. Manganese-induced VEGF promoted tube formation of HUVEC. Taken together, these data suggest that HIF-1 may be a potential mediator of manganese-induced pulmonary inflammation.

  20. A Holocene record of endogenic iron and manganese precipitation and vegetation history in a lake-fen complex in northwestern Minnesota

    USGS Publications Warehouse

    Dean, W.E.; Doner, L.A.

    2012-01-01

    Little Shingobee Lake and Fen are part of the extensive network of lakes and wetlands in the Shingobee River headwaters of northwestern Minnesota, designed to study the interactions between surface and ground waters. Prior to about 11. 2 cal. ka, most of these lakes and wetlands were interconnected to form glacial Lake Willobee, which apparently formed when a debris flow dammed the Shingobee River. Between 11. 2 and 8. 5 cal. ka, the level of Lake Willobee fell as a result of breaching of the dam, transforming the deep lake into the existing lakes and wetlands. Analyses of a 9-m core from Little Shingobee Lake (LSL-B), and lacustrine sediments under 3. 3 m of peat in a 17-m core from Little Shingobee Fen (LSF-10), show that the dominant components are allogenic clastic material, and endogenic CaCO3 and organic matter. In both cores almost all of the iron (Fe) and manganese (Mn) are incorporated in endogenic minerals, presumed to be X-ray amorphous oxyhydroxide minerals, that occur in significant quantities throughout the cores; almost no Fe and Mn are contributed from detrital aluminosilicate minerals. This suggests that, for most of the Holocene, the allogenic watershed contributions to lake chemistry were minor compared to the dissolved mineral load. In addition, prior to 3. 5 cal. ka, pollen zone boundaries coincide with large changes in lake-sediment mineralogy, indicating that both landscape and climate processes were linked to early- and mid-Holocene lake chemistry. The pollen time series, with sequential domination by spruce, pine, sagebrush-oak, birch-oak and, finally, white pine is typical of the region and reflects the changing location of the prairie-forest transition zone over time. These changes in vegetation had some profound effects on the geochemistry of the lake waters. ?? 2011 Springer Science+Business Media B.V. (outside the USA).

  1. THE ROLE OF IRON IN Deinococcus radiodurans ENGINEERED FOR GROWTH ON TOLUENE AND THE ROLE OF MANGANESE IN THE EXTREME RADIATION RESISTANCE PHENOTYPE

    SciTech Connect

    Hassan Brim; Elena K. Gaidamakova; Vera Y. Matrosova; Min Zhai; Amudhan Venkateswaran; Marina Omelchenko; Kira S. Makarova; Lawrence P. Wackett; James K. Fredrickson; Michael J. Daly

    2004-03-17

    Toluene and other fuel hydrocarbons are commonly found in association with radionuclides at numerous Department of Energy (DOE) sites, frequently occurring together with Cr(VI) and other heavy metals. In this study, the extremely radiation resistant bacterium Deinococcus radiodurans was engineered for complete toluene mineralization by cloned expression of tod and xyl genes of Pseudomonas putida. The recombinant Tod/Xyl strain showed significant incorporation of carbon from the toluene aromatic ring into cellular macromolecules and carbon dioxide, in the absence or presence of chronic radiation. We have shown that intracellular iron concentrations in wild-type D. radiodurans in minimal medium are exceptionally low and not sufficient to support growth on toluene using Fe-dependent oxygenases cloned from P. putida. Introducing the fur mutation into D. radiodurans increased intracellular Fe levels, and imparted on the engineered strain the ability to grow on meta-toluate as the sole carbon and energy source. The organism's native Cr(VI) reduction capabilities were facilitated by toluene when present as the sole carbon and energy source in natural sediment analogues of DOE contaminated environments. The engineered bacteria were able to oxidize toluene under both minimal and complex nutrient conditions, which is important since both conditions have environmental equivalents in the context of bioremediation processes. As such, the Tod/Xyl strain is providing a model for understanding the role of Fe and reduction of metals coupled to organic contaminant oxidation in aerobic radionuclide contaminated sediments. We have shown that D. radiodurans contains high intracellular manganese levels, and that Mn restriction sensitizes cells to irradiation. We propose that the unusually high Mn/Fe ratio of D. radiodurans facilitates survival by quenching oxidative stress during recovery.

  2. The origin of manganese-rich metasediments and their relationship to iron formation and base metal deposits, western Georgia piedmont

    SciTech Connect

    Wonder, J.D.

    1987-08-01

    Manganiferous metasediments (coticules), banded iron-formation, and tourmaline-quartz rocks (tourmalinites) are found in close spatial association to each other and to volcanogenic base metal sulfide and gold deposits in the Northern Piedmont of western Georgia. Coticules, which consist of up to 90% garnet and contain from 1 to 15 weight % MnO and 14 to 37 % Fe/sub 2/O/sub 3/, are often hosted by metabasalt. Tourmalinites occur as poorly-bedded aggregates or disseminations and are also found locally associated with metabasalt. Trace element analyses of coticules yield conflicting results. Cu + Co + Ni values and Zr/Cr ratios are low and indicate a hydrothermal origin. Alumina concentrations, Y/P/sub 2/O/sub 5/% ratios, and Th values indicate the probable presence of pelagic sediments in the protolith. Rare earth element patterns are enriched in the light elements and have slight negative Eu anomalies, resembling the patterns of pelagic clays most closely. The protolith of coticules was apparently a hydrothermal sediment with pelagic and/or terrigenous input. Tourmaline in tourmalinites is chemically similar to stratabound sulfide-related examples. Both coticules and tourmalinites are interpreted as metamorphosed seafloor exhalative sediments and thus indicate the potential for the presence of genetically related ore mineralization.

  3. Iron, manganese and copper concentrations in wet precipitations and kinetics of the oxidation of SO 2 in rain water at two urban sites, Jaipur and Kota, in Western India

    NASA Astrophysics Data System (ADS)

    Manoj, S. V.; Mishra, C. D.; Sharma, M.; Rani, A.; Jain, R.; Bansal, S. P.; Gupta, K. S.

    Rain-water samples were collected from Jaipur and Kota in Western India during the monsoon seasons of 1996-1999. In all cases, the pH of rain-water samples exceeded 7.0 and fell in the range (7.1-8.5). In view of the fact that the trace metals particularly iron, manganese and copper have been held responsible for the catalytic activity of rain-water, the chemical analysis of the collected samples was done with regard to the concentrations of these metals. The kinetics of autoxidation of SO 2 has been studied using rain-water samples as medium.

  4. MODIFYING IRON REMOVAL PROCESSES TO INCREASE ARSENIC REMOVAL

    EPA Science Inventory

    Iron and manganese are naturally occurring substances that are normally found in insoluble forms in many ground waters in the US. Similar to iron and manganese, arsenic also occurs widely in the earth's crust and is a natural contaminant of many ground waters. Iron and manganese ...

  5. Effect of manganese and zinc on the growth of Anacystis nidulans

    SciTech Connect

    Lee, L.H.; Lustigman, B.; Dandorf, D. (Montclair State College, Upper Montclair, NJ (United States))

    1994-07-01

    Anacystis nidulans is a unicellular member of the cyanobacteria, one of the largest groups of the Kingdom Monera. It is similar to other bacteria in the structure and chemistry of the cell wall, and its cell division and genetic recombination. Photoautotrophy is the main mode of nutrition and the photosynthetic apparatus is similar to that of other cyanobacteria. Cyanobacteria are excellent organisms to serve as environmental pollution indicators for the investigation of a wide variety of biological problems. There have been several studies on the effects of heavy metals on A. nidulans. Some of these elements, such as manganese, are known to be essential nutrients for cyanobacteria. Others, such as cadmium, are not known to be necessary for normal growth and metabolism. Large amounts of either essential or non-essential elements can be toxic. Manganese and zinc are essential elements for all living organisms. Manganese is a cofactor for a number of different enzymatic reactions particularly those involved in phosphorylation. Iron deficiency induced by a number of metals, cobalt and manganese in particular, inhibit chlorophyll biosynthesis. Zinc deficiency affects early mitotic events and the cells are large and aberrant in appearance. Light is essential for cells to take in zinc. As an industrial contaminant, zinc has been found to block photosynthesis by causing structural damage to the photosynthetic apparatus. In the presence of various pH ranges, high zinc concentrations can be associated with low pH. It has been indicated that pH value and EDTA (Ethylene Diamine Tetraacetic Acid) have an influence on the effect of some metals. The purpose of this study was to determine the effect of manganese and zinc on the growth of Anacystis nidulans, with and without EDTA.

  6. Iron

    MedlinePLUS

    ... disease and restless leg syndrome. Taking iron with levothyroxine can reduce this medication’s effectiveness. Levothyroxine (Levothroid®, Levoxyl®, Synthroid®, Tirosint®, and Unithroid®) is used ...

  7. Application of VNIR diffuse reflectance spectroscopy to estimate soil organic carbon content, and content of different forms of iron and manganese

    NASA Astrophysics Data System (ADS)

    Klement, Ales; Jaksik, Ondrej; Kodesova, Radka; Drabek, Ondrej; Boruvka, Lubos

    2013-04-01

    Visible and near-infrared (VNIR) diffuse reflectance spectroscopy is a progressive method used for prediction of soil properties. Study was performed on the soils from the agricultural land from the south Moravia municipality of Brumovice. Studied area is characterized by a relatively flat upper part, a tributary valley in the middle and a colluvial fan at the bottom. Haplic Chernozem reminded at the flat upper part of the area. Regosols were formed at steep parts of the valley. Colluvial Chernozem and Colluvial soils were formed at the bottom parts of the valley and at the bottom part of the studied field. The goal of the study was to evaluate relationship between soil spectra curves and organic matter content, and different forms iron and manganese content (Mehlich III extract, ammonium oxalate extract and dithionite-citrate extract). Samples (87) were taken from the topsoil within regular grid covering studied area. The soil spectra curves (of air dry soil and sieved using 2 mm sieve) were measured in the laboratory using spectometer FieldSpec®3 (350 - 2 500 nm). The Fe and Mn contents in different extract were measured using ICP-OES (with an iCAP 6500 Radial ICP Emission spectrometer; Thermo Scientific, UK) under standard analytical conditions. Partial least squares regression (PLSR) was used for modeling of the relationship between spectra and measured soil properties. Prediction ability was evaluated using the R2, root mean square error (RMSE) and normalized root mean square deviation (NRMSD). The results showed the best prediction for Mn (R2 = 0.86, RMSE = 29, NRMSD = 0.11), Fe in ammonium oxalate extract (R2 = 0.82, RMSE = 171, NRMSD = 0.12) and organic matter content (R2 = 0.84, RMSE = 0.13, NRMSD = 0.09). The slightly worse prediction was obtained for Mn and Fe in citrate extract (R2 = 0.82, RMSE = 21, NRMSD = 0.10; R2 = 0.77, RMSE = 522, NRMSD = 0.23). Poor prediction was evaluated for Mn and Fe in Mehlich III extract (R2 = 0.43, RMSE = 13, NRMSD = 0.17; R2 = 0.39, RMSE = 13, NRMSD = 0.26). In general, the results confirmed that the measurement of soil spectral characteristics is a promising technology for a digital soil mapping and predicting studied soil properties. Acknowledgment: Authors acknowledge the financial support of the Ministry of Agriculture of the Czech Republic (grant No. QJ1230319) and the Czech Science Foundation (grant No. GA526/09/1762).

  8. Cast B2-phase iron-aluminum alloys with improved fluidity

    DOEpatents

    Maziasz, Philip J. (122 Clark La., Oak Ridge, TN 37830); Paris, Alan M. (P.O. Box 64, Tarrs, PA 15688); Vought, Joseph D. (124 Cove Point Rd., Rockwood, TN 37854)

    2002-01-01

    Systems and methods are described for iron aluminum alloys. A composition includes iron, aluminum and manganese. A method includes providing an alloy including iron, aluminum and manganese; and processing the alloy. The systems and methods provide advantages because additions of manganese to iron aluminum alloys dramatically increase the fluidity of the alloys prior to solidification during casting.

  9. Subcellular distribution of aluminum, bismuth, cadmium, chromium, copper, iron, manganese, nickel, and lead in cultivated mushrooms ( Agaricus bisporus and Pleurotus ostreatus )

    Microsoft Academic Search

    Alma Hortensia Serafín Muñoz; Felix Gutierrez Corona; Kazimierz Wrobel; Gerardo Martínez Soto; Katarzyna Wrobel

    2005-01-01

    In this work, the distribution of nine metals in two types of cultivated mushroom had been investigated. For Agaricus bisporus, the biomass was separated into caps and stalks, and for Pleurotus ostreatus, the entire mushrooms were taken for analysis. Electrothermal atomic absorption spectrometry was used for total element determination\\u000a in acid digests. For accuracy checking, the certified reference material (NIST

  10. Iron and Steel Phosphate Rock

    E-print Network

    Torgersen, Christian

    Phosphate Rock Platinum Potash Pumice Quartz Crystal Rare Earths Rhenium Rubidium Salt Sand and Gravel Cadmium Iodine Pumice Thorium Cement Iron Ore Quartz Crystal Tin Cesium Iron and Steel Rare Earths

  11. (Data in thousand metric tons, gross weight, unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese was not produced domestically

    E-print Network

    Torgersen, Christian

    United States. The majority of ore consumption was related to steel production, directly in pig iron: Domestic manganese demand was bolstered by increased raw steel production through at least the first one Production and Use: Manganese ore containing 35% or more manganese was not produced domestically in 1998

  12. (Data in thousand metric tons gross weight unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese has not been produced

    E-print Network

    Torgersen, Christian

    . Most ore consumption was related to steel production, directly in pig iron manufacture and indirectly to affect the manganese market in 2009. U.S. steel production in 2009 was 40% less than that in 2008 Production and Use: Manganese ore containing 35% or more manganese has not been produced domestically since

  13. (Data in thousand metric tons gross weight unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese has not been produced

    E-print Network

    Torgersen, Christian

    . Most ore consumption was related to steel production, directly in pig iron manufacture and indirectly), coincided with the growth in the manganese market during 2010. U.S. steel production in 2010 was projected Production and Use: Manganese ore containing 35% or more manganese has not been produced domestically since

  14. (Data in thousand metric tons gross weight unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese has not been produced

    E-print Network

    Torgersen, Christian

    . Most ore consumption was related to steel production, directly in pig iron manufacture and indirectly, and Issues: U.S. steel production in 2012 was projected to be 4% more than that in 2011. Imports of manganese Production and Use: Manganese ore containing 35% or more manganese has not been produced domestically since

  15. Assessment of in-plant particulate matter and its toxic metals contents of sponge iron industry in Goa, India.

    PubMed

    Gupta, R K; Bhanarkar, A D; Tamhane, S M; Dhopte, S M

    2010-12-01

    The present study attempted to assess toxic metal contents (Arsenic, Cadmium, Copper, Cobalt, Chromium, Iron, Manganese, Nickel, Lead and Zinc) in Total Suspended Particulate (TSP) and Particulate Matter less than ten micron (PM??) in three sponge iron industries in Goa (India), one of the famous tourist place on the World map. TSP and PM(10) average concentration in all three sponge iron industries were found to be in the range 401-485 ?g/m³ and 135-270 ?g/m³ respectively. Amongst all the metals, concentration of iron was the highest in TSP as well as in PM??. Statistical results indicate that proportion of specific metals were found higher in PM?? as compared to the ratio of PM??/TSP ratio. Value of correlation coefficient was found to be significant for Cr-Pb indicating coal burning was the major source contributor. PMID:21110186

  16. By Thomas S. Jones Manganese (Mn) is essential to iron and silicomanganese increased about 7%. consisted of, in tons, natural battery-grade ore,

    E-print Network

    Torgersen, Christian

    about 7%. consisted of, in tons, natural battery-grade ore, steel production by virtue of its sulfur aluminum alloys and is used in oxide form in dry cell batteries. The overall level and nature of manganese consumption in batteries was denoted by the expansion on schedule of domestic capacity for production

  17. A Holocene record of endogenic iron and manganese precipitation, isotopic composition of endogenic carbonate, and vegetation history in a lake-fen complex in northwestern Minnesota

    USGS Publications Warehouse

    Dean, Walter E.; Doner, Lisa A.

    2011-01-01

    Little Shingobee Lake and Fen are part of an extensive network of lakes and wetlands in the Shingobee River headwaters area of northwestern Minnesota. Prior to about 9800 radiocarbon years, most of the lakes in the Shingobee watershed area were interconnected to form glacial Lake Willobee. From 9800 to 7700 radiocarbon years, the level of Lake Willobee fell as a result of breaching of a dam, leaving small separated basins containing the existing lakes and wetlands. The dominant components in the sediments in a 9-meter core from Little Shingobee Lake (LSL-B), and lacustrine sediments under 3.3 meters of peat in a 17-meter core from Little Shingobee Fen (LSF-10) are detrital clastic material, endogenic CaCO3, and organic matter. The detrital fraction in the Holocene section in core LSL-B varies considerably from 7 weight percent to 82 weight percent and closely parallels the concentration of detrital quartz measured by X-ray diffraction. The CaCO3 concentration, which also varies considerably from 10 weight percent to 70 weight percent, is generally antithetic to the detrital concentration owing to the dilution of detrital material by CaCO3, particularly during the early to middle Holocene (about 9000-6500 calendar years). The organic-matter content varies from 5 weight percent to 25 weight percent and, together with CaCO3, serves to dilute the allogenic detrital fraction. In both cores almost all of the iron (Fe) and manganese (Mn) is in endogenic minerals, presumed to be oxyhydroxide minerals, that are important components throughout the core; little Fe and Mn are contributed by detrital aluminosilicate minerals. The endogenic Fe mineral, calculated as Fe(OH)3, forms a larger percentage of the sediment than endogenic organic material throughout most of the Holocene section in the LSL-B core and in the lacustrine sediments below the peat in the LSF-10 core. Biogenic silica as opal (biopal; diatom debris) was not measured, but the average calculated biopal is 5 percent in the LSL-B core and 15.5 percent in the LSF-10 core. Values of delta18O in mollusk (Pisidium) and ostracode shells increase by only about 20 per mil from the bottom to the top of the LSL-B core (about 12600-2200 calendar years). The remarkably constant oxygen-isotope composition throughout the Holocene suggests that environmental conditions affecting values of delta18O (temperature, salinity, composition of the water, composition of precipitation) did not change greatly. Values of delta13C in carbonate shells generally decreased by about 2 per mil from 9000 calendar years to 6000 calendar years, but they did not increase in organic carbon. This mid-Holocene increase in delta13C in shells but not in organic carbon is likely due to an increase in residence time. A late Pleistocene forest dominated by spruce was replaced in the early Holocene by a pine forest. The pine forest migrated east during the middle Holocene and was replaced by an open sagebrush-oak savanna. The western migration of forests into northwestern Minnesota is marked first by a hardwood forest and finally a pine forest.

  18. Synthesis and determination of manganese carbonate and manganese-54 carbonate

    SciTech Connect

    King, B.D.; Lassiter, J.W.; Neathery, M.W.; Miller, W.J.

    1980-04-01

    A method was developed by which radioactive manganese, manganese-54 carbonate could be produced. This was accomplished by reacting manganese-54 chloride, manganese chloride tetrahydrate, and sodium bicarbonate. This reaction produced manganese-54 carbonate mixed with stable manganese. The purity of the manganese carbonate (manganese-54 carbonate) was determined by the use of x-ray diffraction methods. All material was the carbonate form of manganese (manganese-54 carbonate).

  19. Iron, copper, zinc, and manganese transport and regulation in pathogenic Enterobacteria: correlations between strains, site of infection and the relative importance of the different metal transport systems for virulence

    PubMed Central

    Porcheron, Gaëlle; Garénaux, Amélie; Proulx, Julie; Sabri, Mourad; Dozois, Charles M.

    2013-01-01

    For all microorganisms, acquisition of metal ions is essential for survival in the environment or in their infected host. Metal ions are required in many biological processes as components of metalloproteins and serve as cofactors or structural elements for enzymes. However, it is critical for bacteria to ensure that metal uptake and availability is in accordance with physiological needs, as an imbalance in bacterial metal homeostasis is deleterious. Indeed, host defense strategies against infection either consist of metal starvation by sequestration or toxicity by the highly concentrated release of metals. To overcome these host strategies, bacteria employ a variety of metal uptake and export systems and finely regulate metal homeostasis by numerous transcriptional regulators, allowing them to adapt to changing environmental conditions. As a consequence, iron, zinc, manganese, and copper uptake systems significantly contribute to the virulence of many pathogenic bacteria. However, during the course of our experiments on the role of iron and manganese transporters in extraintestinal Escherichia coli (ExPEC) virulence, we observed that depending on the strain tested, the importance of tested systems in virulence may be different. This could be due to the different set of systems present in these strains, but literature also suggests that as each pathogen must adapt to the particular microenvironment of its site of infection, the role of each acquisition system in virulence can differ from a particular strain to another. In this review, we present the systems involved in metal transport by Enterobacteria and the main regulators responsible for their controlled expression. We also discuss the relative role of these systems depending on the pathogen and the tissues they infect. PMID:24367764

  20. Synthesis and determination of manganese carbonate and manganese-54 carbonate

    Microsoft Academic Search

    B. D. King; J. W. Lassiter; M. W. Neathery; W. J. Miller

    1980-01-01

    A method was developed by which radioactive manganese, manganese-54 carbonate could be produced. This was accomplished by reacting manganese-54 chloride, manganese chloride tetrahydrate, and sodium bicarbonate. This reaction produced manganese-54 carbonate mixed with stable manganese. The purity of the manganese carbonate (manganese-54 carbonate) was determined by the use of x-ray diffraction methods. All material was the carbonate form of manganese

  1. Golgi Phosphoprotein 4 (Gpp130) Is A Sensitive And Selective Cellular Target Of Manganese Exposure

    E-print Network

    Masuda, Melisa Junko

    2012-01-01

    iron regulation by in vitro manganese exposure in undifferentiated PC12 cells. Brainiron, may be effluxed by ferroportin, and that elevated exposures to Mn may induce ferroportin expression in brain (brain. Recent studies suggest that cellular Mn, like iron,

  2. Biological manganese removal from acid mine drainage in constructed wetlands and prototype bioreactors

    Microsoft Academic Search

    Kevin B. Hallberg; D. Barrie Johnson

    2005-01-01

    Mine drainage waters vary considerably in the range and concentration of heavy metals they contain. Besides iron, manganese is frequently present at elevated concentrations in waters draining both coal and metal mines. Passive treatment systems (aerobic wetlands and compost bioreactors) are designed to remove iron by biologically induced oxidation\\/precipitation. Manganese, however, is problematic as it does not readily form sulfidic

  3. New. J. Chem., 1992, 16, 633-642 THE PHOTOCHEMISTRY OF CHROMIUM, MANGANESE,

    E-print Network

    Suslick, Kenneth S.

    New. J. Chem., 1992, 16, 633-642 THE PHOTOCHEMISTRY OF CHROMIUM, MANGANESE, AND IRON PORPHYRIN, 799 7. ABSTRACT. - A review is presented of the photochemistry of porphyrin complexes of the first row transition metals, particularly those of chromium, manganese, and iron. Their photochemistry has revealed

  4. [Ferrous-manganese oxidizing bacteria from the nature water].

    PubMed

    Qin, Song-yan; Ma, Fang; Huang, Peng

    2008-06-01

    Glass slides were hanged into a canal to acquire the ferrous-manganese oxidizing bacteria settled bio-film. Two isolated methods for ferrous-manganese oxidizing bacteria with special iron-manganese oxidizing matrix from the bio-film were tested. Element component of bacteria product and sheath structure of bacteria were analyzed. With two methods, plate cultivation and the novel semi-solid in situ cultivation method, strains belong to Family Leptothrix were isolated. XRF showed that the amorphous iron and manganese were two major metal elements of the precipitation formed by one strain of Leptothrix spp.. Through the microscope observation, one strain of Family Leptothrix was determined to form branch-like structured sheath, while another strain formed spider web-like structured sheath. Those isolated bacteria provide model strains for future testing of FISH probe and PCR primer of ferrous-manganese oxidizing bacteria. PMID:18763517

  5. Cadmium | Cancer Trends Progress Report

    Cancer.gov

    Cadmium is an element found in low concentrations in the earth’s crust. It is usually found as a mineral combined with other elements such as oxygen (cadmium oxide), chlorine (cadmium chloride), or sulfur (cadmium sulfate, cadmium sulfide).

  6. Chronic manganese intoxication

    SciTech Connect

    Huang, C.C.; Chu, N.S.; Lu, C.S.; Wang, J.D.; Tsai, J.L.; Tzeng, J.L.; Wolters, E.C.; Calne, D.B. (Chang Gung Medical College Hospital, Taipei, Taiwan (China))

    1989-10-01

    We report six cases of chronic manganese intoxication in workers at a ferromanganese factory in Taiwan. Diagnosis was confirmed by assessing increased manganese concentrations in the blood, scalp, and pubic hair. In addition, increased manganese levels in the environmental air were established. The patients showed a bradykinetic-rigid syndrome indistinguishable from Parkinson's disease that responded to treatment with levodopa.

  7. Manganese in Narragansett Bay

    Microsoft Academic Search

    WILLIAM F. GRAHAM; MICHAEL L. BENDER; GARY P. KLINKHAMMER

    1976-01-01

    Concentrations of dissolved manganese and particulate mangancsc and aluminum were determined in samples from Narragansett Bay, Rhode Island, and its surrounding rivers. Total manganese is approximately conservative, but dissolved and particulate manganese are not. Desorption may occur in the tidal rivers at low salinities. Most riverine manga- nest is dissolved but mangancsc in the bay is predominantly particulate, probably due

  8. Field Evaluations of Yield, Iron-Manganese Relationship, and Chlorophyll Meter Readings in Soybean Genotypes as Affected by Iron-Ethylenediamine Di-o-hydroxyphenylacetic Acid in a Calcareous Soil

    Microsoft Academic Search

    A. Ronaghi; R. Ghasemi-Fasaei

    2007-01-01

    Iron (Fe)-deficiency chlorosis is a common constraint when soybean (Glycine max L.) is grown on calcareous soils. Considerable differences exist among soybean genotypes for susceptibility to Fe chlorosis. In order to evaluate the effectiveness of iron-ethylenediamine di-o-hydroxyphenylacetic acid (Fe-EDDHA) for three soybean genotypes (A3237, Black hack, and Wells), field studies were conducted for the years 2001 and 2002 in a

  9. Assessment of the permissible exposure level to manganese in workers exposed to manganese dioxide dust

    Microsoft Academic Search

    H A Roels; P Ghyselen; J P Buchet; E Ceulemans; R R Lauwerys

    1992-01-01

    The prevalence of neuropsychological and respiratory symptoms, lung ventilatory parameters, neurofunctional performances (visual reaction time, eye-hand coordination, hand steadiness, audioverbal short term memory), and several biological parameters (calcium, iron, luteinising hormone (LH), follicle stimulating hormone (FSH), and prolactin concentrations in serum, blood counts, manganese (Mn) concentration in blood and in urine) were examined in a group of workers (n =

  10. Iron and Steel Phosphate Rock

    E-print Network

    Torgersen, Christian

    Phosphate Rock Platinum Potash Pumice Quartz Crystal Rare Earths Rhenium Rubidium Salt Sand and Gravel Platinum Tellurium Bromine Indium Potash Thallium Cadmium Iodine Pumice Thorium Cement Iron Ore Quartz

  11. Synthesis and determination of manganese carbonate and manganese-54 carbonate.

    PubMed

    King, B D; Lassiter, J W; Neathery, M W; Miller, W J

    1980-04-01

    A method was developed by which radioactive manganese, manganese-54 carbonate (with a high specific activity), could be produced. This was accomplished by reacting manganese-54 chloride, manganese chloride tetrahydrate, and sodium bicarbonate. This reaction produced manganese-54 carbonate (specific activity .35 mCi/mg manganese mixed with stable manganese. The purity of the manganese carbonate (manganese-54 carbonate) was determined by the use of x-ray diffraction methods. One method compared "d" spacings (distance in angstroms between lattice planes of a crystal) with standard and index values for pure manganese carbonate. Another method compared x-ray diffractograms of the synthesized product with standard manganese carbonate. By both methods all material was the carbonate form of manganese (manganese-54 carbonate). PMID:7381087

  12. Manganese resources of the Cuyuna range, east-central Minnesota

    SciTech Connect

    Beltrame, R.J.; Holtzman, R.C.; Wahl, T.E.

    1981-01-01

    The Cuyuna range, located in east-central Minnesota, consists of a sequence of argillite, siltstone, iron-formation, graywacke, slate, and quartzite of early Proterozoic age. Manganese-bearing materials occur within the iron-rich strata of the Trommald Formation and the Rabbit Lake Formation. Computer-assisted resource estimates, based on exploration drill hole information, indicate that the Cuyuna range contains a minimum of 176 million metric tons (MMT) of marginally economic manganiferous rock with an average grade of 10.46 weight percent manganese. The calculated 18.5 MMT of manganese on the Cuyuna range could supply this country's needs for this important and strategic metal for nearly 14 years. An additional resource of 6.9 MMT of manganese metal is available in the lower grade deposits The vast majority of these calculated resources are extractable by current surface mining techniques.

  13. (Data in thousand metric tons, gross weight, unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese was not produced domestically

    E-print Network

    Torgersen, Christian

    United States. The majority of ore consumption was related to steel production, directly in pig iron.2 Electrolytic metal 9 0.5 9 2 1r Events, Trends, and Issues: Although raw steel production, a major determinant Production and Use: Manganese ore containing 35% or more manganese was not produced domestically in 1997

  14. (Data in thousand metric tons gross weight unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese has not been produced

    E-print Network

    Torgersen, Christian

    . Most ore consumption was related to steel production, directly in pig iron manufacture and indirectly 91 -- Ferromanganese, high-carbon 356 356 91 34 Events, Trends, and Issues: U.S. steel production Production and Use: Manganese ore containing 35% or more manganese has not been produced domestically since

  15. (Data in thousand metric tons gross weight unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese was not produced domestically

    E-print Network

    Torgersen, Christian

    consumption was related to steel production, directly in pig iron manufacture and indirectly through upgrading in producer and consumer stock releases. Through September 2008, domestic steel production was 4% higher than Production and Use: Manganese ore containing 35% or more manganese was not produced domestically in 2008

  16. (Data in thousand metric tons, gross weight, unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese was not produced domestically

    E-print Network

    Torgersen, Christian

    United States. The majority of ore consumption was related to steel production, directly in pig iron metal 10 0.02 10 2 Events, Trends, and Issues: A slight further advance in raw steel production Production and Use: Manganese ore containing 35% or more manganese was not produced domestically in 1996

  17. (Data in thousand metric tons, gross weight, unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese was not produced domestically

    E-print Network

    Torgersen, Christian

    and the Midwestern United States. Most ore consumption was related to steel production, directly in pig iron 2 Events, Trends, and Issues: Through September, steel production, the principal determinant Production and Use: Manganese ore containing 35% or more manganese was not produced domestically in 2002

  18. Cadmium inhalation and male reproductive toxicity

    SciTech Connect

    Ragan, H.A.; Mast, T.J. (Battelle Pacific Northwest Laboratories, Richland, WA (USA))

    1990-01-01

    Cadmium is a highly toxic element that is cumulative and has a long biological half-life in mammals. The severe toxicity of cadmium in man has been known for more than 100 years. Despite the knowledge that cadmium is toxic, only 20 human cases of poisoning via ingestion were recorded prior to 1941, whereas in the ensuing five-year period more than 680 cases of cadmium poisonings from accidental oral ingestion of this metal were documented. Some of the recorded effects of exposure to cadmium in laboratory animals include renal tubular damage, placental and testicular necrosis, structural and functional liver damage, osteomalacia, testicular tumors, teratogenic malformations, anemia, hypertension, pulmonary edema, chronic pulmonary emphysema, and induced deficiencies of iron, copper, and zinc. Some of these effects have also been observed in human after accidental exposures to cadmium oxide fumes and are characteristic of the syndrome described in Japan as Itai Itai disease in which ingestion of cadmium is the inciting chemical.134 references.

  19. Sources of cadmium in the environment

    SciTech Connect

    Hutton, M.

    1983-02-01

    This paper is concerned with quantifying the major sources of cadmium in the European Community and assessing the relative significance of such inputs to the environmental compartments, air, land, and water. The methodology involved identification of potential sources of cadmium, including natural processes, as well as those associated with human activities. This was followed by a review of any emission studies of these processes and subsequent estimation of an emission factor for each source. The emission factor was applied to the most recent production or consumption data for the process in question to obtain an estimate of the annual discharge. The steel industry and waste incineration, followed by volcanic action and zinc production, are estimated to account for the largest emissions of atmospheric cadmium in the region. Waste disposal results in the single largest input of cadmium to land; the quantity of cadmium associated with this source is greater than the total from the four other major sources--coal combustion, iron and steel production, phosphate fertilizer manufacture and use, and zinc production. The characterization of cadmium inputs to aquatic systems is incomplete but of the sources considered, the manufacture of cadmium-containing articles accounts for the largest discharge, followed by phosphate fertilizer manufacture and zinc production.

  20. Zinc dependence of zinT (yodA) mutants and binding of zinc, cadmium and mercury by ZinT

    SciTech Connect

    Kershaw, Christopher J.; Brown, Nigel L. [School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Hobman, Jon L. [School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)], E-mail: jon.hobman@nottingham.ac.uk

    2007-12-07

    ZinT (B1973), previously known as YodA, was originally characterised as a cadmium-induced periplasmic protein under the regulation of Fur and SoxS. Here we describe a decrease in zinT transcript in response to elevated copper concentrations and the zinc and copper dependent phenotype of a {delta}zinT strain. Cadmium sensitivity of the {delta}zinT strain was not observed. We demonstrate the binding of nickel, zinc, cadmium, and mercury, but not cobalt, copper, iron, and manganese, to purified ZinT using mass spectrometry. This and previous studies support the hypothesis that ZinT plays a role in zinc homeostasis and is required for growth under zinc limited conditions, suggesting that ZinT is either a periplasmic zinc chaperone or is involved in zinc import. Limited metal ion discrimination results in regulation of PzinT in a non-specific manner, which is mirrored in the binding of several different heavy metals by ZinT.

  1. Manganese 2 -Complexes as Auxiliaries

    E-print Network

    Lepore, Salvatore D.

    reaction with methylcyclopentadienyl manganese tricarbonyl. This complex readily underwent aldol reactions by Franck-Neumann demonstrating that alkynyl esters 2 -complexed to methylcyclopentadienyl manganeseManganese 2 -Complexes as Auxiliaries for Stereoselective Aldol Synthesis of Allenyl Carbinols

  2. Arsenic removal by manganese greensand filters

    SciTech Connect

    Phommavong, T. [Saskatchewan Environment, Regina (Canada); Viraraghavan, T. [Univ. of Regina, Saskatchewan (Canada). Faculty of Engineering

    1994-12-31

    Some of the small communities in Saskatchewan are expected to have difficulty complying with the new maximum acceptable concentration (MAC) of 25 {micro}g/L for arsenic. A test column was set up in the laboratory to study the removal of arsenic from the potable water using oxidation with KMnO{sub 4}, followed by manganese greensand filtration. Tests were run using water from the tap having a background arsenic concentration of <0.5 {micro}g/L and iron concentration in the range of 0.02 to 0.77 mg/L. The test water was spiked with arsenic and iron. Results showed that 61 % to 98% of arsenic can be removed from the potable water by oxidation with KMnO{sub 4} followed by manganese greensand filtration.

  3. Ferromagnetic Resonance in Manganese Ferrite Single Crystals

    Microsoft Academic Search

    P. E. Tannenwald

    1955-01-01

    The microwave properties of two types of manganese ferrite single crystals have been investigated by means of the ferromagnetic resonance phenomenon from 300°K to 4.2°K and at 24 000, 9100, 5600, and 2800 Mc\\/sec. The low resistivity of one of the crystals, believed to be related to the presence of divalent iron, led to significantly different microwave behavior. Resonance lines

  4. Characterization of alkaline manganese dioxide products containing no lead added zinc alloys

    SciTech Connect

    West, J.T.; Bonacker, F.F. [Rayovac Corp., Madison, WI (United States)

    1995-12-31

    Environmental pressures have resulted in major efforts by consumer battery manufacturers to significantly reduce the toxic heavy-metal content of alkaline manganese dioxide cells. The performance characteristics of mercury- and cadmium-free products containing no lead-added zinc alloys have been evaluated and compared to mercury and cadmium-free products containing lead-bearing alloys. The effects of the absence of mercury, cadmium and lead are reported. The efforts of the battery industry to deal with the observed problems is reflected in awarded patents and an abundance of patent applications involving the group of metals: bismuth, indium, gallium, thallium, calcium, aluminum, and strontium.

  5. The trial of regeneration of used impregnated activated carbons after manganese sorption

    Microsoft Academic Search

    Ewa Okoniewska; Joanna Lach; Ma?gorzata Kacprzak; Ewa Neczaj

    2008-01-01

    In recent years, the increasing level of underground water shows a high iron and manganese concentrations, thus, the technology of water treatment requires application of processes for Fe and Mn removal. Within a literature, many treatment processes have been proposed for manganese removal from drinking water, however very often they do not comply with the obligatory quality standards and are

  6. Multiedge refinement of extended x-ray-absorption fine structure of manganese zinc ferrite nanoparticles

    Microsoft Academic Search

    S. Calvin; E. E. Carpenter; B. Ravel; V. G. Harris; S. A. Morrison

    2002-01-01

    The structure of nanoparticle manganese zinc ferrites synthesized by a reverse micellar method is determined by analysis of the extended x-ray-absorption fine structure in combination with other techniques. Both empirical and theoretical standards are employed; manganese, zinc, and iron edges are refined simultaneously. It is determined that samples synthesized under similar conditions sometimes exhibit a markedly different distribution of cations

  7. Ferromagnetism in Manganese Compounds

    Microsoft Academic Search

    R. O. Zaitsev

    1998-01-01

    The ferromagnetic instability in a system of manganese cations and oxygen, nitrogen and phosphorus anions on the basis of the strong electron-electron interaction is studied. The phase diagram for the existence of ferromagnetic ordering depending on the filling p6-shells of anions and dl0-shells of manganese is constructed.

  8. BIOLOGICAL EFFECTS OF MANGANESE

    EPA Science Inventory

    The biological effects of manganese were studied in a town on the coast of Dalmatia in which a ferromanganese plant has been operating since before World War II. The study focused on the question of whether the exposure to manganese can cause a higher incidence of respiratory dis...

  9. Biomarkers of Manganese Intoxication

    PubMed Central

    Zheng, Wei; Fu, Sherleen X.; Dydak, Ulrike; Cowan, Dallas M.

    2010-01-01

    Manganese (Mn), upon absorption, is primarily sequestered in tissue and intracellular compartments. For this reason, blood Mn concentration does not always accurately reflect Mn concentration in the targeted tissue, particularly in the brain. The discrepancy between Mn concentrations in tissue or intracellular components means that blood Mn is a poor biomarker of Mn exposure or toxicity under many conditions and that other biomarkers must be established. For group comparisons of active workers, blood Mn has some utility for distinguishing exposed from unexposed subjects, although the large variability in mean values renders it insensitive for discriminating one individual from the rest of the study population. Mn exposure is known to alter iron (Fe) homeostasis. The Mn/Fe ratio (MIR) in plasma or erythrocytes reflects not only steady-state concentrations of Mn or Fe in tested individuals, but also a biological response (altered Fe homeostasis) to Mn exposure. Recent human studies support the potential value for using MIR to distinguish individuals with Mn exposure. Additionally, magnetic resonance imaging (MRI), in combination with noninvasive assessment of ?-aminobutyric acid (GABA) by magnetic resonance spectroscopy (MRS), provides convincing evidence of Mn exposure, even without clinical symptoms of Mn intoxication. For subjects with long-term, low-dose Mn exposure or for those exposed in the past but not the present, neither blood Mn nor MRI provides a confident distinction for Mn exposure or intoxication. While plasma or erythrocyte MIR is more likely a sensitive measure, the cut-off values for MIR among the general population need to be further tested and established. Considering the large accumulation of Mn in bone, developing an X-ray fluorescence spectroscopy or neutron-based spectroscopy method may create yet another novel non-invasive tool for assessing Mn exposure and toxicity. PMID:20946915

  10. Process for producing cadmium sulfide on a cadmium telluride surface

    DOEpatents

    Levi, Dean H. (Lakewood, CO); Nelson, Art J. (Longmont, CO); Ahrenkiel, Richard K. (Lakewood, CO)

    1996-01-01

    A process for producing a layer of cadmium sulfide on a cadmium telluride surface to be employed in a photovoltaic device. The process comprises providing a cadmium telluride surface which is exposed to a hydrogen sulfide plasma at an exposure flow rate, an exposure time and an exposure temperature sufficient to permit reaction between the hydrogen sulfide and cadmium telluride to thereby form a cadmium sulfide layer on the cadmium telluride surface and accomplish passivation. In addition to passivation, a heterojunction at the interface of the cadmium sulfide and the cadmium telluride can be formed when the layer of cadmium sulfide formed on the cadmium telluride is of sufficient thickness.

  11. Effects of time, soil organic matter, and iron oxides on the relative retention and redistribution of lead, cadmium, and copper on soils.

    PubMed

    Diagboya, Paul N; Olu-Owolabi, Bamidele I; Adebowale, Kayode O

    2015-07-01

    In order to predict the bioavailability of toxic metals in soils undergoing degradation of organic matter (OM) and iron oxides (IOs), it is vital to understand the roles of these soil components in relation to metal retention and redistribution with time. In this present work, batch competitive sorptions of Pb(II), Cu(II), and Cd(II) were investigated between 1 and 90 days. Results showed that competition affected Cd(II) sorption more than Cu(II) and Pb(II). The sorption followed the trend Pb(II) >?>?Cu(II)?>?Cd(II), irrespective of aging, and this high preference for Pb(II) ions in soils reduced with time. Removal of OM led to reduction in distribution coefficient (K d) values of ?33 % for all cations within the first day. However, K d increased nearly 100 % after 7 days and over 1000 % after 90-day period. The enhanced K d values indicated that sorptions occurred on the long run on surfaces which were masked by OM. Removal of IO caused selective increases in the K d values, but this was dependent on the dominant soil constituent(s) in the absence of IO. The K d values of the IO-degraded samples nearly remained constant irrespective of aging indicating that sorptions on soil components other than the IO are nearly instantaneous while iron oxides played greater role than other constituents with time. Hence, in the soils studied, organic matter content determines the immediate relative metal retention while iron oxides determine the redistribution of metals with time. PMID:25721528

  12. Effects of methionine chelate- or yeast proteinate-based supplement of copper, iron, manganese and zinc on broiler growth performance, their distribution in the tibia and excretion into the environment.

    PubMed

    Singh, Abhay Kumar; Ghosh, Tapan Kumar; Haldar, Sudipto

    2015-04-01

    A straight-run flock of 1-day-old Cobb 400 chicks (n?=?432) was distributed into four treatment groups (9 replicate pens in each group, 12 birds in a pen) for a 38-day feeding trial evaluating the effects of a methionine chelate (Met-TM)- or a yeast proteinate (Yeast-TM)-based supplement of copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn) on growth performance, bone criteria and some metabolic indices in commercial broiler chickens. The diets were either not supplemented with any trace elements at all (negative control, NC) or supplemented with an inorganic (sulphate) trace element premix (inorganic TM (ITM), 1 g/kg feed), the Met-TM (1 g/kg feed) and the Yeast-TM (0.5 g/kg feed). Body weight, feed conversion ratio and dressed meat yield at 38 days were better in the Yeast-TM-supplemented group as compared with the NC, ITM and Met-TM groups (p?

  13. Longitudinal MRI contrast enhanced monitoring of early tumour development with manganese chloride (MnCl2) and superparamagnetic iron oxide nanoparticles (SPIOs) in a CT1258 based in vivo model of prostate cancer

    PubMed Central

    2012-01-01

    Background Cell lines represent a key tool in cancer research allowing the generation of neoplasias which resemble initial tumours in in-vivo animal models. The characterisation of early tumour development is of major interest in order to evaluate the efficacy of therapeutic agents. Magnetic resonance imaging (MRI) based in-vivo characterisation allows visualisation and characterisation of tumour development in early stages prior to manual palpation. Contrast agents for MRI such as superparamagnetic iron oxide nanoparticles (SPIOs) and manganese chloride (MnCl2) represent powerful tools for the in-vivo characterisation of early stage tumours. In this experimental study, we labelled prostate cancer cells with MnCl2 or SPIOs in vitro and used 1?T MRI for tracing labelled cells in-vitro and 7?T MRI for tracking in an in-vivo animal model. Methods Labelling of prostate cancer cells CT1258 was established in-vitro with MnCl2 and SPIOs. In-vitro detection of labelled cells in an agar phantom was carried out through 1?T MRI while in-vivo detection was performed using 7?T MRI after subcutaneous (s.c.) injection of labelled cells into NOD-Scid mice (n?=?20). The animals were scanned in regular intervals until euthanization. The respective tumour volumes were analysed and corresponding tumour masses were subjected to histologic examination. Results MnCl2in-vitro labelling resulted in no significant metabolic effects on proliferation and cell vitality. In-vitro detection-limit accounted 105 cells for MnCl2 as well as for SPIOs labelling. In-vivo 7?T MRI scans allowed detection of 103 and 104 cells. In-vivo MnCl2 labelled cells were detectable from days 4–16 while SPIO labelling allowed detection until 4?days after s.c. injection. MnCl2 labelled cells were highly tumourigenic in NOD-Scid mice and the tumour volume development was characterised in a time dependent manner. The amount of injected cells correlated with tumour size development and disease progression. Histological analysis of the induced tumour masses demonstrated characteristic morphologies of prostate adenocarcinoma. Conclusions To the best of our knowledge, this is the first study reporting direct in-vitro MnCl2 labelling and 7?T based in-vivo MRI tracing of cancer cells in a model of prostate cancer. MnCl2 labelling was found to be suitable for in-vivo tracing allowing long detection periods. The labelled cells kept their highly tumourigenic potential in-vivo. Tumour volume development was visualised prior to manual palpation allowing tumour characterisation in early stages of the disease. PMID:22784304

  14. Cellular Iron Distribution in Bacillus anthracis

    PubMed Central

    Tu, Wang Yung; Pohl, Susanne; Gray, Joe; Robinson, Nigel J.; Harwood, Colin R.

    2012-01-01

    Although successful iron acquisition by pathogens within a host is a prerequisite for the establishment of infection, surprisingly little is known about the intracellular distribution of iron within bacterial pathogens. We have used a combination of anaerobic native liquid chromatography, inductively coupled plasma mass spectrometry, principal-component analysis, and peptide mass fingerprinting to investigate the cytosolic iron distribution in the pathogen Bacillus anthracis. Our studies identified three of the major iron pools as being associated with the electron transfer protein ferredoxin, the miniferritin Dps2, and the superoxide dismutase (SOD) enzymes SodA1 and SodA2. Although both SOD isozymes were predicted to utilize manganese cofactors, quantification of the metal ions associated with SodA1 and SodA2 in cell extracts established that SodA1 is associated with both manganese and iron, whereas SodA2 is bound exclusively to iron in vivo. These data were confirmed by in vitro assays using recombinant protein preparations, showing that SodA2 is active with an iron cofactor, while SodA1 is cambialistic, i.e., active with manganese or iron. Furthermore, we observe that B. anthracis cells exposed to superoxide stress increase their total iron content more than 2-fold over 60 min, while the manganese and zinc contents are unaffected. Notably, the acquired iron is not localized to the three identified cytosolic iron pools. PMID:22178968

  15. Chelation of cadmium by combining deferasirox and deferiprone in rats.

    PubMed

    Jamilaldin Fatemi, S; Saljooghi, Amir Shokooh; Balooch, Faezeh Dahooee; Iranmanesh, Marzieh; Golbafan, Mohammad Reza

    2011-05-01

    The present research aimed to characterize the potential efficiency of two chelators after cadmium administration for 60 days following two dose levels of 20 and 40 mg/kg body weight daily to male rats. However, the hypothesis that the two chelators might be more efficient as combined therapy than as single therapy in removing cadmium from the body was considered. In this way, two known chelators deferasirox and deferiprone (L(1)) were chosen and tested in the acute rat model. Two chelators were given orally as a single or combined therapy for the period of a week. Cadmium and iron concentrations in various tissues were determined by graphite furnace and flame atomic absorption spectrometry methods, respectively. The combined chelation therapy results show that Deferasirox and L(1) are able to remove cadmium ions from the body while iron concentration returned to the normal level and symptoms are also decreased. PMID:21245204

  16. Health effects of cadmium exposure--a review of the literature and a risk estimate.

    PubMed

    Järup, L; Berglund, M; Elinder, C G; Nordberg, G; Vahter, M

    1998-01-01

    This report provides a review of the cadmium exposure situation in Sweden and updates the information on health risk assessment according to recent studies on the health effects of cadmium. The report focuses on the health effects of low cadmium doses and the identification of high-risk groups. The diet is the main source of cadmium exposure in the Swedish nonsmoking general population. The average daily dietary intake is about 15 micrograms/day, but there are great individual variations due to differences in energy intake and dietary habits. It has been shown that a high fiber diet and a diet rich in shellfish increase the dietary cadmium intake substantially. Cadmium concentrations in agricultural soil and wheat have increased continuously during the last century. At present, soil cadmium concentrations increase by about 0.2% per year. Cadmium accumulates in the kidneys. Human kidney concentrations of cadmium have increased several fold during the last century. Cadmium in pig kidney has been shown to have increased by about 2% per year from 1984-1992. There is no tendency towards decreasing cadmium exposure among the general nonsmoking population. The absorption of cadmium in the lungs is 10-50%, while the absorption in the gastrointestinal tract is only a few percent. Smokers have about 4-5 times higher blood cadmium concentrations (about 1.5 micrograms/l), and twice as high kidney cortex cadmium concentrations (about 20-30 micrograms/g wet weight) as nonsmokers. Similarly, the blood cadmium concentrations are substantially elevated in persons with low body iron stores, indicating increased gastrointestinal absorption. About 10-40% of Swedish women of child-bearing age are reported to have empty iron stores (S-ferritin < 12 micrograms/l). In general, women have higher concentrations of cadmium in blood, urine, and kidney than men. The population groups at highest risk are probably smokers, women with low body iron stores, and people habitually eating a diet rich in cadmium. According to current knowledge, renal tubular damage is probably the critical health effect of cadmium exposure, both in the general population and in occupationally exposed workers. Tubular damage may develop at much lower levels than previously estimated, as shown in this report. Data from several recent reports from different countries indicate that an average urinary cadmium excretion of 2.5 micrograms/g creatinine is related to an excess prevalence of renal tubular damage of 4%. An average urinary excretion of 2.5 micrograms/g creatinine corresponds to an average concentration of cadmium in renal cortex of 50 micrograms/g, which would be the result of long-term (decades) intake of 50 micrograms per day. When the critical concentrations for adverse effects due to cadmium accumulation are being evaluated, it is crucial to consider both the individual variation in kidney cadmium concentrations and the variations in sensitivity within the general population. Even if the population average kidney concentration is relatively low for the general population, a certain proportion will have values exceeding the concentration where renal tubular damage can occur. It can be estimated that, at the present average daily intake of cadmium in Sweden, about 1% of women with low body iron stores and smokers may experience adverse renal effects related to cadmium. If the average daily intake of cadmium would increase to 30 micrograms/day, about 1% of the entire population would have cadmium-induced tubular damage. In risk groups, for example, women with low iron stores, the percentage would be higher, up to 5%. Both human and animal studies indicate that skeletal damage (osteoporosis) may be a critical effect of cadmium exposure. We conclude, however, that the present evidence is not sufficient to permit such a conclusion for humans. We would like to stress, however, that osteoporosis is a very important public health problem worldwide, but especially in the Scandinav PMID:9569444

  17. Adsorption of mixed metals and cadmium by calcium-alginate immobilized Zoogloea ramigera

    Microsoft Academic Search

    Sabine P. Kuhn; Robert M. Pfister

    1989-01-01

    Zoogloea ramigera 115 cells were immobilized into beads of calcium alginate and used in air-bubbled column reactors to remove cadmium (Cd), zinc (Zn), manganese (Mn), lead (Pb), copper (Cu) and strontium (Sr) from dilute and concentrated solutions. By placing three bubble columns in sequence it was possible to achieve Cd adsorption efficiencies of 99% or greater. During ten applications of

  18. Cadmium and renal cancer

    SciTech Connect

    Il'yasova, Dora [Department of Cancer Biology, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157 (United States); Department of Public Health Sciences, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157 (United States); Schwartz, Gary G. [Department of Cancer Biology, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157 (United States) and Department of Public Health Sciences, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157 (United States)]. E-mail: gschwart@wfubmc.edu

    2005-09-01

    Background: Rates of renal cancer have increased steadily during the past two decades, and these increases are not explicable solely by advances in imaging modalities. Cadmium, a widespread environmental pollutant, is a carcinogen that accumulates in the kidney cortex and is a cause of end-stage renal disease. Several observations suggest that cadmium may be a cause of renal cancer. Methods: We performed a systematic review of the literature on cadmium and renal cancer using MEDLINE for the years 1966-2003. We reviewed seven epidemiological and eleven clinical studies. Results: Despite different methodologies, three large epidemiologic studies indicate that occupational exposure to cadmium is associated with increased risk renal cancer, with odds ratios varying from 1.2 to 5.0. Six of seven studies that compared the cadmium content of kidneys from patients with kidney cancer to that of patients without kidney cancer found lower concentrations of cadmium in renal cancer tissues. Conclusions: Exposure to cadmium appears to be associated with renal cancer, although this conclusion is tempered by the inability of studies to assess cumulative cadmium exposure from all sources including smoking and diet. The paradoxical findings of lower cadmium content in kidney tissues from patients with renal cancer may be caused by dilution of cadmium in rapidly dividing cells. This and other methodological problems limit the interpretation of studies of cadmium in clinical samples. Whether cadmium is a cause of renal cancer may be answered more definitively by future studies that employ biomarkers of cadmium exposure, such as cadmium levels in blood and urine.

  19. Effects of organic amendments on manganese toxicity in potatoes as measured by sand and soil culture studies

    Microsoft Academic Search

    B. T. Cheng; G. J. Ouellette

    1971-01-01

    Summary  Soil and sand culture studies were carried out in the greenhouse to investigate the influence of organic amendments on the\\u000a rate of mineralization of manganese and iron in different soil types of Quebec. Potatoes (Early Rose variety which is resistant\\u000a to manganese toxicity) grown in culture solution containing 100 ppm of manganese produced flowers two weeks in advance of\\u000a those

  20. Drinking Water Problems: Iron and Manganese (Spanish)

    E-print Network

    Dozier, Monty; McFarland, Mark L.

    2004-02-20

    ?s efectivo que el cloro para oxidar el manganeso a niveles de pH mayores que 7.5. El permanganato de potasio es venenoso y es un irritante para la piel. No debe haber exceso de permanganato de potasio en el agua tratada y el qu?mico concentrado debe ser...

  1. Manganese and iron in Indian Ocean waters

    NASA Astrophysics Data System (ADS)

    Saager, Paul M.; De Baar, Hein J. W.; Burkill, Peter H.

    1989-09-01

    The first vertical profiles of dissolved Mn and Fe for the (NW) Indian Ocean are reported. The area is characterized by seasonal upwelling and a broad oxygen minimum zone in intermediate waters. The dissolved Fe-profile exhibits a maximum (5.1 nM) in the oxygen minimum zone, with low values both in surface waters (0.3 nM) and deep waters (around 1 nM). Mn concentrations in the surface waters are elevated (2.0-4.3 nM), and decrease rapidly in an offshore direction. Below the first 25 m, concentrations decrease dramatically (0.5-1.3 nM), indicating removal by oxidation and particle scavenging. Further down, various Mn maxima are observed which can be related to hydrographic features (sigma-?): 1. Intermediate water originating from the Red Sea lost its dissolved O 2 while flowing northward along the Omani coast and exhibits a strong Mn maximum (4.6-6.5 nM) coincident with the deep O 2 minimum. 2. At the two inshore stations in the Gulf of Oman this is overlain by relatively modest Mn maxima (±2.7 nM) related to Arabian Gulf overflow water. 3. Finally the strong Mn maxima (4.4-5.6 nM) in the oxygen minimum zone at the two offshore stations are related to yet another watermass. Below these various maxima, concentrations decrease gradually to values as low as 90 pM at 2000 meters depth. Towards the seafloor concentrations increase again, leading to a modest bottom water maximum (0.7-1.5 nM). The overall vertical distributions of Mn and Fe are strikingly similar, also in actual concentrations, to those previously reported for the eastern equatorial Pacific, an area also characterized by an extensive O 2-minimum zone.

  2. Drinking Water Problems: Iron and Manganese (Spanish) 

    E-print Network

    Dozier, Monty; McFarland, Mark L.

    2004-02-20

    ?nicos) debido a que pueden tapar el aspirador y el filtro. Oxidaci?n qu?mica Niveles altos de hierro y manganeso disuelto u oxi- dado (combinaciones combinadas de hasta 25 mg/L) pueden ser tratadas por oxidaci?n qu?mica. Este m?todo es particularmente de ayuda...

  3. CADMIUM SOLUBILITY IN PADDY SOILS: EFFECTS OF SOIL OXIDATION, METAL SULFIDES AND COMPETITIVE IONS.

    EPA Science Inventory

    Cadmium (Cd) is a non-essential element for human nutrition and is an agricultural soil contaminant. Cadmium solubility in paddy soils affects Cd accumulation in the grain of rice. This is a human health risk, exacerbated by the fact that rice grains are deficient in iron (Fe) an...

  4. Manganese micro-nodules on ancient brick walls.

    PubMed

    López-Arce, P; García-Guinea, J; Fierro, J L G

    2003-01-20

    Romans, Jews, Arabs and Christians built the ancient city of Toledo (Spain) with bricks as the main construction material. Manganese micro-nodules (circa 2 microm in diameter) have grown under the external bio-film surface of the bricks. Recent anthropogenic activities such as industrial emissions, foundries, or traffic and housing pollution have further altered these old bricks. The energy-dispersive X-ray microanalyses (XPS) of micro-nodules show Al, Si, Ca, K, Fe and Mn, with some carbon species. Manganese atoms are present only as Mn(4+) and iron as Fe(3+) (FeOOH-Fe(2)O(3) mixtures). The large concentration of alga biomass of the River Tagus and the Torcón and Guajaraz reservoirs suggest manganese micro-nodules are formed either from water solutions rich in anthropogenic MnO(4)K in a reduction environment (from Mn(7+) to Mn(4+)) or by oxidation mechanisms from dissolved Mn(2+) (from Mn(2+) to Mn(4+)) linked to algae biofilm onto the ancient brick surfaces. Ancient wall surfaces were also studied by scanning electron microscopy (SEM-EDS) and X-ray diffraction (XRD). Chemical and biological analyses of the waters around Toledo are also analysed for possible sources of manganese. Manganese micro-nodules on ancient brick walls are good indicators of manganese pollution. PMID:12526915

  5. Cadmium - a metallohormone?

    PubMed Central

    Byrne, Celia; Divekar, Shailaja D.; Storchan, Geoffrey B.; Parodi, Daniela A.; Martin, Mary Beth

    2009-01-01

    Cadmium is a heavy metal that is often referred to as the metal of the 20th Century. It is widely used in industry principally in galvanizing and electroplating, in batteries, in electrical conductors, in the manufacture of alloys, pigments, and plastics, and in the stabilization of phosphate fertilizers. As a byproduct of smelters, cadmium is a prevalent environmental contaminant. In the general population, exposure to cadmium occurs primarily through dietary sources, cigarette smoking, and, to a lesser degree, drinking water. Although the metal has no known physiological function, there is evidence to suggest that the cadmium is a potent metallohormone. This review summarizes the increasing evidence that cadmium mimics the function of steroid hormones, addresses our current understanding of the mechanism by which cadmium functions as a hormone, and discusses its potential role in development of the hormone dependent cancers. PMID:19362102

  6. Fur Is Involved in Manganese-Dependent Regulation of mntA (sitA) Expression in Sinorhizobium meliloti

    PubMed Central

    Platero, Raúl; Peixoto, Lucía; O'Brian, Mark R.; Fabiano, Elena

    2004-01-01

    Fur is a transcriptional regulator involved in iron-dependent control of gene expression in many bacteria. In this work we analyzed the phenotype of a fur mutant in Sinorhizobium meliloti, an ?-proteobacterium that fixes N2 in association with host plants. We demonstrated that some functions involved in high-affinity iron transport, siderophore production, and iron-regulated outer membrane protein expression respond to iron in a Fur-independent manner. However, manganese-dependent expression of the MntABCD manganese transport system was lost in a fur strain as discerned by constitutive expression of a mntA::gfp fusion reporter gene in the mutant. Thus, Fur directly or indirectly regulates a manganese-dependent function. The data indicate a novel function for a bacterial Fur protein in mediating manganese-dependent regulation of gene expression. PMID:15240318

  7. Fur is involved in manganese-dependent regulation of mntA (sitA) expression in Sinorhizobium meliloti.

    PubMed

    Platero, Raúl; Peixoto, Lucía; O'Brian, Mark R; Fabiano, Elena

    2004-07-01

    Fur is a transcriptional regulator involved in iron-dependent control of gene expression in many bacteria. In this work we analyzed the phenotype of a fur mutant in Sinorhizobium meliloti, an alpha-proteobacterium that fixes N(2) in association with host plants. We demonstrated that some functions involved in high-affinity iron transport, siderophore production, and iron-regulated outer membrane protein expression respond to iron in a Fur-independent manner. However, manganese-dependent expression of the MntABCD manganese transport system was lost in a fur strain as discerned by constitutive expression of a mntA::gfp fusion reporter gene in the mutant. Thus, Fur directly or indirectly regulates a manganese-dependent function. The data indicate a novel function for a bacterial Fur protein in mediating manganese-dependent regulation of gene expression. PMID:15240318

  8. Cadmium, lead and endometriosis

    Microsoft Academic Search

    J. F. Heilier; J. Donnez; V. Verougstraete; O. Donnez; F. Grandjean; V. Haufroid; F. Nackers; D. Lison

    2006-01-01

    Objectives: Cadmium (Cd) and lead (Pb) have been demonstrated to exert endocrine disrupting activities. Their possible role in endometriosis, an oestrogen-dependent disease, is unknown. Methods: We compared cadmium urinary excretion (CdU) and blood concentration of cadmium (CdB) and lead (PbB) in 119 patients with peritoneal endometriosis and\\/or deep endometriotic (adenomyotic) nodules of the rectovaginal septum and 25 controls. Results: The

  9. The ubiquity of iron.

    PubMed

    Frey, Perry A; Reed, George H

    2012-09-21

    The importance of iron in living systems can be traced to the many complexes within which it is found, to its chemical mobility in undergoing oxidation-reduction reactions, and to the abundance of iron in Earth's crust. Iron is the most abundant element, by mass, in the Earth, constituting about 80% of the inner and outer cores of Earth. The molten outer core is about 8000 km in diameter, and the solid inner core is about 2400 km in diameter. Iron is the fourth most abundant element in Earth's crust. It is the chemically functional component of mononuclear iron complexes, dinuclear iron complexes, [2Fe-2S] and [4Fe-4S] clusters, [Fe-Ni-S] clusters, iron protophorphyrin IX, and many other complexes in protein biochemistry. Metals such as nickel, cobalt, copper, and manganese are present in the crust and could in principle function chemically in place of iron, but they are scarce in Earth's crust. Iron is plentiful because of its nuclear stability in stellar nuclear fusion reactions. It seems likely that other solid planets, formed by the same processes as Earth, would also foster the evolution of life and that iron would be similarly important to life on those planets as it is on Earth. PMID:22845493

  10. Bioaccumulation of manganese and its toxicity in feral pigeons (Columba livia) exposed to manganese oxide dust (Mn3O4).

    PubMed

    Sierra, P; Chakrabarti, S; Tounkara, R; Loranger, S; Kennedy, G; Zayed, J

    1998-11-01

    Manganese tetroxide (Mn3O4) is a product from the combustion of methylcyclopentadienyl manganese tricarbonyl. Exposure to high levels of manganese can lead to serious health effects especially to the central nervous and respiratory systems. Very few studies on the effects of long-term low level exposure to Mn3O4 have been reported. The present study was therefore conducted to examine the bioaccumulation and toxicity of manganese in various organs of feral pigeons (Columba livia) when exposed to low levels of Mn3O4 via inhalation and hence to find any possible relationship between these two parameters. A total of 22 pigeons was exposed to 239 micrograms/m3 of manganese for 7 h/day, 5 days/week for 5, 9, and 13 consecutive weeks. Manganese concentrations in various tissues, e.g., brain (mesencephalon), lung, liver, intestine, pancreas, kidney, muscle, bone, and whole blood, were measured by neutron activation analysis. Various biochemical parameters in blood, e.g., hematocrit, total proteins, glucose, uric acid, alanine aminotransferase, total iron, blood urea nitrogen and triglycerides, were also measured. Manganese concentrations in brain, lung, and bone were significantly higher in Mn3O4-exposed pigeons (0.59, 0.58, and 3.02 micrograms wet tissue, respectively) than in the control group (0.46, 0.19, 1.74 micrograms/g wet tissue, respectively). However, except for total proteins such exposure did not produce any changes in various biochemical parameters which were within the normal values. Thus these results have shown that, despite significant bioaccumulation of manganese in some tissues, no significant toxic effects could be seen. PMID:9841807

  11. ARSENIC REMOVAL BY IRON REMOVAL PROCESSES

    EPA Science Inventory

    Presentation will discuss the removal of arsenic from drinking water using iron removal processes that include oxidation/filtration and the manganese greensand processes. Presentation includes results of U.S. EPA field studies conducted in Michigan and Ohio on existing iron remo...

  12. Clinical evaluation of Deferasirox for removal of cadmium ions in rat.

    PubMed

    Saljooghi, Amir Shokooh; Fatemi, S Jamil A

    2010-08-01

    An investigation was conducted to evaluate the ability of Deferasirox (ICL670 or Exjade) following the distribution of cadmium salt in male Wistar rats. Cadmium was introduced to several groups of weanling male Wistar rats through different means, by act of drinking, feeding. A control group was fed on a diet containing normal level of iron. After a period of 30 days, all the rats administered cadmium were severely anemic and showed toxicity symptoms through loss of hair and increasing in cadmium and reduction in iron levels in blood. Chelation therapy was carried out to remove the toxic element from the body. The ability of Deferasirox chelator in removing cadmium was investigated this chelator for 1 week to the remaining rats of similar groups. The results showed that the cadmium level present in blood was significantly reduced and at the same time, iron concentration returned to the normal level. It was concluded that Deferasirox chelator is able to remove cadmium from the body and could be used for the treatment of complications and eradication of symptoms of cadmium intoxication. PMID:20401682

  13. Thermodynamic analysis of manganese

    Microsoft Academic Search

    A. Fernández Guillermet; W. Huang

    1990-01-01

    A description of the Gibbs energy of the various solid modifications of manganese at 101325 Pa has been obtained for the whole temperature range from 298 K to the melting point. The present analysis accounts for the effect of a magnetic transition in a-, ?-, and d-Mn, which is treated using the Inden-Hillert-Jarl phenomenological model for the magnetic Gibbs energy.

  14. Manganese resources of the Cuyuna range, east-central Minnesota. Report of Investigations 24

    SciTech Connect

    Beltrame, R.J.; Holtzman, R.C.; Wahl, T.E.

    1981-01-01

    The Cuyuna range, located in east-central Minnesota, consists of a sequence of argillite, siltstone, iron-formation, graywacke, slate, and quartzite of early Proterozoic age. Manganese-bearing materials occur within the iron-rich strata of the Trommald Formation and the Rabbit Lake Formation. Computer-assisted resource estimates, based on exploration drill hole information, indicate that the Cuyuna range contains a minimum of 176 million metric tons (MMT) of marginally economic manganiferous rock with an average grade of 10.46 weight percent manganese. The calculated 18.5 MMT of manganese on the Cuyuna range could supply this country's needs for this important and strategic metal for nearly 14 years. An additional resource of 6.9 MMT of manganese metal is available in the lower grade deposits. The vast majority of these calculated resources are extractable by current surface mining techniques.

  15. Metallic solvent extraction of manganese and titanium from ferroalloys

    NASA Astrophysics Data System (ADS)

    Godsell, A. J.; Fray, D. J.

    1990-04-01

    The selective removal of valuable elements from ferroalloys has been investigated. It has been found that liquid bismuth is a suitable solvent for leaching manganese from its ferroalloy. High recoveries and rapid reaction rates were obtained for low-carbon ferromanganese, but results for the high-carbon ferromanganese and silicomanganese were less favorable due to the lower activity of manganese in these alloys and the lack of wetting by liquid bismuth. Antimony was found to be a suitable solvent for titanium from ferrotitanium but iron was also taken into solution. Manganese was successfully transferred from solution in liquid bismuth to liquid aluminum by fused salt electrorefining, using a NaCl-KCl-MnCl electrolyte, at high current efficiencies with negligible carryover of bismuth.

  16. Biological manganese removal from acid mine drainage in constructed wetlands and prototype bioreactors.

    PubMed

    Hallberg, Kevin B; Johnson, D Barrie

    2005-02-01

    Mine drainage waters vary considerably in the range and concentration of heavy metals they contain. Besides iron, manganese is frequently present at elevated concentrations in waters draining both coal and metal mines. Passive treatment systems (aerobic wetlands and compost bioreactors) are designed to remove iron by biologically induced oxidation/precipitation. Manganese, however, is problematic as it does not readily form sulfidic minerals and requires elevated pH (>8) for abiotic oxidation of Mn (II) to insoluble Mn (IV). As a result, manganese removal in passive remediation systems is often less effective than removal of iron. This was found to be the case at the pilot passive treatment plant (PPTP) constructed to treat water draining the former Wheal Jane tin mine in Cornwall, UK, where effective removal of manganese occurred only in one of the three rock filter components of the composite systems over a 1-year period of monitoring. Water in the two rock filter systems where manganese removal was relatively poor was generally manganese removal were due to variable performances in the compost bioreactors that feed the rock filter units in the composite passive systems at Wheal Jane. An alternative approach for removing soluble manganese from mine waters, using fixed bed bioreactors, was developed. Ferromanganese nodules (about 2 cm diameter), collected from an abandoned mine adit in north Wales, were used to inoculate the bioreactors (working volume ca. 700 ml). Following colonization by manganese-oxidizing microbes, the aerated bioreactor catalysed the removal of soluble manganese, via oxidation of Mn (II) and precipitation of the resultant Mn (IV) in the bioreactor, in synthetic media and mine water from the Wheal Jane PPTP. Such an approach has potential application for removing soluble Mn from mine streams and other Mn-contaminated water courses. PMID:15680632

  17. Reversed Phase Extraction Chromatographic Separation of Manganese(II) with Tributyl Phosphate

    Microsoft Academic Search

    Chhaya Dixit; S. M. Khopkar

    1985-01-01

    The extraction chromatography of manganese(II) was developed using tributyl phosphate as extractant from thiocyanate media with silica gel as the stationary phase. Manganese was extracted from 1.5 M ammonium thiocyanate, stripped with mineral acids and determined spectrophotometrically at 450 nm. It was separated from alkali metals, Mo(VI), nickel, silver and lead by selective extraction, and from iron(III), zinc, cobalt by

  18. Process for removing technetium from iron and other metals

    DOEpatents

    Leitnaker, J.M.; Trowbridge, L.D.

    1999-03-23

    A process for removing technetium from iron and other metals comprises the steps of converting the molten, alloyed technetium to a sulfide dissolved in manganese sulfide, and removing the sulfide from the molten metal as a slag. 4 figs.

  19. Synthesis and characterization of iron(III), manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of salicylidene-N-anilinoacetohydrazone (H2L1) and 2-hydroxy-1-naphthylidene-N-anilinoacetohydrazone (H2L2).

    PubMed

    AbouEl-Enein, S A; El-Saied, F A; Kasher, T I; El-Wardany, A H

    2007-07-01

    Salicylidene-N-anilinoacetohydrazone (H(2)L(1)) and 2-hydroxy-1-naphthylidene-N-anilinoacetohydrazone (H(2)L(2)) and their iron(III), manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes have been synthesized and characterized by IR, electronic spectra, molar conductivities, magnetic susceptibilities and ESR. Mononuclear complexes are formed with molar ratios of 1:1, 1:2 and 1:3 (M:L). The IR studies reveal various modes of chelation. The electronic absorption spectra and magnetic susceptibility measurements show that the iron(III), nickel(II) and cobalt(II) complexes of H(2)L(1) have octahedral geometry. While the cobalt(II) complexes of H(2)L(2) were separated as tetrahedral structure. The copper(II) complexes have square planar stereochemistry. The ESR parameters of the copper(II) complexes at room temperature were calculated. The g values for copper(II) complexes proved that the Cu-O and Cu-N bonds are of high covalency. PMID:17113342

  20. 21 CFR 73.2775 - Manganese violet.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...Identity. The color additive manganese violet is a violet pigment obtained by reacting phosphoric acid, ammonium dihydrogen...and manganese dioxide at temperatures above 450 °F. The pigment is a manganese ammonium pyrophosphate complex having the...

  1. 21 CFR 73.2775 - Manganese violet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...Identity. The color additive manganese violet is a violet pigment obtained by reacting phosphoric acid, ammonium dihydrogen...and manganese dioxide at temperatures above 450 °F. The pigment is a manganese ammonium pyrophosphate complex having the...

  2. 21 CFR 73.2775 - Manganese violet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...Identity. The color additive manganese violet is a violet pigment obtained by reacting phosphoric acid, ammonium dihydrogen...and manganese dioxide at temperatures above 450 °F. The pigment is a manganese ammonium pyrophosphate complex having the...

  3. 21 CFR 73.2775 - Manganese violet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Identity. The color additive manganese violet is a violet pigment obtained by reacting phosphoric acid, ammonium dihydrogen...and manganese dioxide at temperatures above 450 °F. The pigment is a manganese ammonium pyrophosphate complex having the...

  4. 21 CFR 73.2775 - Manganese violet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...Identity. The color additive manganese violet is a violet pigment obtained by reacting phosphoric acid, ammonium dihydrogen...and manganese dioxide at temperatures above 450 °F. The pigment is a manganese ammonium pyrophosphate complex having the...

  5. Manganese Accumulates within Golgi Apparatus in Dopaminergic Cells as Revealed by Synchrotron X-ray Fluorescence Nanoimaging

    PubMed Central

    2009-01-01

    Chronic exposure to manganese results in neurological symptoms referred to as manganism and is identified as a risk factor for Parkinson’s disease. In vitro, manganese induces cell death in the dopaminergic cells, but the mechanisms of manganese cytotoxicity are still unexplained. In particular, the subcellular distribution of manganese and its interaction with other trace elements needed to be assessed. Applying synchrotron X-ray fluorescence nanoimaging, we found that manganese was located within the Golgi apparatus of PC12 dopaminergic cells at physiologic concentrations. At increasing concentrations, manganese accumulates within the Golgi apparatus until cytotoxic concentrations are reached resulting in a higher cytoplasmic content probably after the Golgi apparatus storage capacity is exceeded. Cell exposure to manganese and brefeldin A, a molecule known to specifically cause the collapse of the Golgi apparatus, results in the striking intracellular redistribution of manganese, which accumulates in the cytoplasm and the nucleus. These results indicate that the Golgi apparatus plays an important role in the cellular detoxification of manganese. In addition manganese exposure induces a decrease in total iron content, which could contribute to the overall neurotoxicity. PMID:22778823

  6. Journal of Materials Science, Vol. 39, 2004, 39493955. CarbonCarbon Interactions in Iron

    E-print Network

    Cambridge, University of

    Journal of Materials Science, Vol. 39, 2004, 3949­3955. Carbon­Carbon Interactions in Iron H. K. D interstitial sites in iron so that the configurations of any solid­solution at constant composition depend atoms. INTRODUCTION There are no solutions of iron which are ideal. The iron­manganese liquid phase

  7. The vapour pressures over saturated aqueous solutions of cadmium chloride, cadmium bromide, cadmium iodide, cadmium nitrate, and cadmium sulphate

    Microsoft Academic Search

    Alexander Apelblat; Eli Korin

    2007-01-01

    Vapour pressures of water over saturated solutions of cadmium salts (chloride, bromide, iodide, nitrate, and sulphate) were determined over the temperature range 280K to 322K and compared with the literature data. The vapour pressures determined were used to obtain the water activities, osmotic coefficients and the molar enthalpies of vaporization in the (cadmium salt+water) systems.

  8. Bacteriology of Manganese Nodules

    PubMed Central

    Ehrlich, H. L.

    1968-01-01

    A cell-free extract from Arthrobacter 37, isolated from a manganese nodule from the Atlantic Ocean, exhibited enzymatic activity which accelerated manganese accretion to synthetic Mn-Fe oxide as well as to crushed manganese nodule. The reaction required oxygen and was inhibited by HgCl2 and p-chloromercuribenzoate but not by Atebrine dihydrochloride. The rate of enzymatic action depended on the concentration of cell-free extract used. The enzymatic activity had a temperature optimum around 17.5 C and was destroyed by heating at 100 C. The amount of heat required for inactivation depended on the amount of nucleic acid in the preparation. In the cell-free extract, unlike the whole-cell preparation, peptone could not substitute for NaHCO3 in the reaction mixture. An enzyme-containing protein fraction and a nucleic acid fraction could be separated from cell extract by gel filtration, when prepared in 3% NaCl but not in seawater. The nucleic acid fraction was not required for enzymatic activity. PMID:5645405

  9. Characterization of cadmium uptake in Lactobacillus plantarum and isolation of cadmium and manganese uptake mutants

    SciTech Connect

    Hao, Z.; Reiske, H.R.; Wilson, D.B.

    1999-11-01

    Two different Cd{sup 2+} uptake systems were identified in Lactobacillus plantarum. One is a high-affinity, high-velocity Mn{sup 2+} uptake system which also takes up Cd{sup 2+} and is induced by Mn{sup 2+} starvation. The calculated K{sub m} and V{sub max} are 0.26 {mu}M and 3.6 {mu}mol g of dry cell{sup {minus}1} min{sup {minus}1}, respectively. Unlike Mn{sup 2+} uptake, which is facilitated by citrate and related tricarboxylic acids, Cd{sup 2+} uptake is weakly inhibited by citrate. Cd{sup 2+} and Mn{sup 2+} are competitive inhibitors of each other, and the affinity of the system for Cd{sup 2+} is higher than that for Mn{sup 2+}. The other Cd{sup 2+} uptake system is expressed in Mn{sup 2+}-sufficient cells, and no K{sub m} can be calculated for it because uptake is nonsaturable. Mn{sup 2+} does not compete for transport through this system, nor does any other tested cation, i.e., Zn{sup 2+}, Cu{sup 2+}, Co{sup 2+}, Mg{sup 2+}, Ca{sup 2+}, Fe{sup 2+}, or Ni{sup 2+}. Both systems require energy, since uncouplers completely inhibit their activities. Two Mn{sup 2+}-dependent L. plantarum mutants were isolated by chemical mutagenesis and ampicillin enrichment. They required more than 5,000 times as much Mn{sup 2+} for growth as the parental strain. Mn{sup 2+} starvation-induced Cd{sup 2+} uptake in both mutants was less than 5% the wild-type rate. The low level of long-term Mn{sup 2+} or Cd{sup 2+} accumulation by the mutant strains also shows that the mutations eliminate the high-affinity Mn{sup 2+} and Cd{sup 2+} uptake system.

  10. (Data in thousand metric tons, gross weight, unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese was not produced

    E-print Network

    Torgersen, Christian

    and the Midwestern United States. Most ore consumption was related to steel production, directly in pig iron for manganese ferroalloy demand usually falls in the range of 1% to 2% and is tied to steel production. Through the first 8 months of 2003, however, domestic steel production was the same as that for the same period

  11. Cadmium migration in aerospace nickel cadmium cells

    NASA Technical Reports Server (NTRS)

    Mcdermott, P. P.

    1976-01-01

    The effects of temperature, the nature of separator material, charge and discharge, carbonate contamination, and the mode of storage are studied with respect to the migration of active material from the negative toward the positive plate. A theoretical model is proposed which takes into account the solubility of cadmium in various concentrations of hydroxide and carbonate at different temperatures, the generation of the cadmiate ion, Cd(OH)3(-), during discharge, the migration of the cadmiate ion and particulate Cd(OH)2 due to electrophoretic effects and the movement of electrolyte in and out of the negative plate and, finally, the recrystallization of cadmiate ion in the separator as Cd(OH)2. Application of the theoretical model to observations of cadmium migration in cycled cells is also discussed.

  12. Study of hazardous metals in iron slag waste using laser induced breakdown spectroscopy.

    PubMed

    Gondal, M A; Hussain, T; Yamani, Z H; Bakry, A H

    2007-05-01

    Laser Induced Breakdown Spectroscopy (LIBS) was applied for quantitative elemental analysis of slag samples collected from a local steel plant using an Nd: YAG laser emitting radiation at 1064 nm wavelength. The concentration of different elements of environmental significance such as cadmium, calcium, sulfur, magnesium, chromium, manganese, titanium, barium, phosphorus and silicon were 44, 2193, 1724,78578, 217260, 22220, 5178, 568, 2805, 77871 were mg Kg-1, respectively. Optimal experimental conditions for analysis were investigated. The calibration curves were drawn for different elements. The concentrations determined with our Laser-Induced Breakdown Spectrometers were compared with the results obtained using Inductively Coupled Plasma (ICP) emission spectroscopy. Our study demonstrates that LIBS could be highly appropriate for rapid online analysis of iron slag waste. The relative accuracy of our LIBS system for various elements as compared with ICP method is in the range of 0.001-0.049 at 2.5% error confidence. Limits of detection (LOD) of our LIBS system were also estimated for the elements noted here. The hazardous effects of some of the trace elements present in iron slag exceeding permissible safe limits are also discussed. PMID:17474003

  13. Fatal cadmium-induced pneumonitis.

    PubMed

    Seidal, K; Jörgensen, N; Elinder, C G; Sjögren, B; Vahter, M

    1993-12-01

    A previously relatively healthy 78-year-old man was exposed to cadmium fumes during brazing with cadmium-containing silver solder. He developed severe chemical pneumonitis and died 25 d after exposure. PMID:8153597

  14. THE MANGANESE MERCURY STAR ?1 BOOTIS

    PubMed Central

    Montgomery, John Wm.; Aller, Lawrence H.

    1969-01-01

    High-dispersion plates secured with the Coudé spectrograph of the Lick 120 inch telescope have been used to analyze the peculiar A star ?1 Bootis. Spectral-energy distribution measurements are combined with line-intensity data for iron and manganese in two stages of ionization to obtain a fit with model atmospheres for Teff = 13,000°K and log g = 4. The influence of adopted T and g on the derived abundances is discussed. Although C, O, Mg, Si, Ti, Cr, and Fe appear to have nearly normal (i.e., solar) abundances, strontium appears to be enhanced in abundance by an order of magnitude, and scandium is about 50 times overabundant, while manganese and yttrium appear to be two orders of magnitude overabundant. If the identification of gallium is correct, this element is overabundant by a factor approaching 100,000; while if ?3983.90 is to be attributed to HgII, as Bidelman suggests, the overabundance of this element is many orders of magnitude. PMID:16578698

  15. The magnetic properties of the iron-rich, iron-nickel-zinc alloys

    E-print Network

    Gupton, Paul Stephen

    1961-01-01

    . 010 0. 006 Report on analysis of typical data on block zinc as supplied by American Smelting and Refining Company Houston, Texas Zinc Lead Iron Cadmium Others not over Free from aluminum 99. 98 X . 006 . 005 . 004 . 010 43 Results...THE MAGNETIC PROPERTIES OF THE IRON-RICH, IRON-NICKEL-ZINC ALLOYS A Thesis By Paul Stephen Gupton Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements for the degree...

  16. Multiedge refinement of extended x-ray-absorption fine structure of manganese zinc ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Calvin, S.; Carpenter, E. E.; Ravel, B.; Harris, V. G.; Morrison, S. A.

    2002-12-01

    The structure of nanoparticle manganese zinc ferrites synthesized by a reverse micellar method is determined by analysis of the extended x-ray-absorption fine structure in combination with other techniques. Both empirical and theoretical standards are employed; manganese, zinc, and iron edges are refined simultaneously. It is determined that samples synthesized under similar conditions sometimes exhibit a markedly different distribution of cations between the available sites in the spinel structure; this in turn causes significant differences in the magnetic properties of the samples. In addition, it is found that the mean-square displacements for manganese-oxygen bonds are consistently higher than for zinc-oxygen bonds, perhaps due to the presence of manganese ions of more than one valence.

  17. Clinical evaluation of Deferasirox for removal of cadmium ions in rat

    Microsoft Academic Search

    Amir Shokooh Saljooghi; S. Jamil A. Fatemi

    2010-01-01

    An investigation was conducted to evaluate the ability of Deferasirox (ICL670 or Exjade) following the distribution of cadmium\\u000a salt in male Wistar rats. Cadmium was introduced to several groups of weanling male Wistar rats through different means, by\\u000a act of drinking, feeding. A control group was fed on a diet containing normal level of iron. After a period of 30 days,

  18. Urinary cadmium and beta2?microglobulin: Correlation with nutrition and smoking history

    Microsoft Academic Search

    Norman E. Kowal

    1988-01-01

    Urinary cadmium and beta2?microglobulin concentrations from approximately 1000 samples from the general adult U.S. population, collected as part of the National Health and Nutritional Examination Survey II (NHANES II), were related to nutritional and smoking history of the individuals. Urinary cadmium concentration was negatively correlated with dietary iron (significance level of 0.0065), negatively correlated with dietary calcium (significance level of

  19. Separation, preconcentration, and determination of cadmium in drinking waters.

    PubMed

    Stafilov, T; Pavlovska, G; Cundeva, K; Zendelovska, D; Paneva, V

    2001-05-01

    A fast method for separation, preconcentration and determination of cadmium in drinking (source, well, tap) and water for irrigation is described. Iron(III) hexamethylenedithiocarbamate, Fe(HMDTC)3, has the role of colloid precipitate flotation collector. The determination of cadmium in final water solutions preconcentrated by flotation can be performed by flame (FAAS) or electrothermal atomic absorption spectrometry (ETAAS). The method applied, either FAAS or ETAAS, depends of the concentration level of analyte in the water sample investigating. The AAS results are compared with inductively coupled plasma-atomic emission spectrometric measurements (ICP-AES) as an independent method. The ETAAS detection limit of cadmium is 0.002 microgram/L. PMID:11460328

  20. Effect of iron and manganese contents on convection-free precipitation and sedimentation of primary ?-Al(FeMn)Si phase in liquid Al11.5Si0.4Mg alloy

    Microsoft Academic Search

    X. Cao; N. Saunders; J. Campbell

    2004-01-01

    The effect of Fe and Mn contents on precipitation and sedimentation of primary a-Al(FeMn)Si phase in liquid Al-11.5Si-0.4Mg (wt%) alloy has been investigated at 600°C in convection-free conditions. Almost all primary a-Al(FeMn)Si particles and some oxide films seem to completely settle to the base of the melts. With the increase of original iron equivalent values (IEV) or Mn\\/Fe ratio at

  1. Nickel-cadmium battery recycling through the INMETCO{reg_sign} high temperature metals recovery process

    SciTech Connect

    Liotta, J.J.; Onuska, J.C.; Hanewald, R.H. [INMETCO, Ellwood City, PA (United States)

    1995-07-01

    INMETCO, a subsidiary of Inco Limited, is the only facility in North America that provides the High Temperature Metals Recovery (HTMR) process for nickel-cadmium batteries. In 1993, INMETCO recycled more than 2,200 tons of nickel-cadmium, nickel-iron and nickel metal hydride batteries. The paper describes Inco`s experience in metals recovery, traces the development and explains operation of the HTMR Process and outlines INMETCO`s plans for cadmium recovery at its facility in Ellwood City, Pennsylvania.

  2. Nickel and manganese transfer from soil to plant in lateritic mining soils from New Caledonia

    Microsoft Academic Search

    P. Pouschat; J. Rose; I. Alliot; C. Dominici; C. Keller; I. Laffont-Schwob; L. Olivi; J.-P. Ambrosi

    2009-01-01

    New Caledonian ferritic soils (more than 50 % of iron) are naturally rich in metals (chromium, nickel, cobalt, and manganese), deficient in major nutrients (nitrogen, phosphorous, and potassium), and unbalanced for the calcium\\/magnesium ratio. Under these particular ecological conditions, New Caledonia, recognized as a hot-spot of biodiversity, is a natural laboratory to study and understand the adaptation strategies of plants

  3. Factors influencing intestinal cadmium uptake in pregnant Bangladeshi women-A prospective cohort study

    SciTech Connect

    Kippler, M. [Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm (Sweden)] [Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm (Sweden); Goessler, W. [Institut fuer Chemie-Analytische Chemie, Karl-Franzens-Universitaet, Universitaetsplatz 1, 8010 Graz (Austria)] [Institut fuer Chemie-Analytische Chemie, Karl-Franzens-Universitaet, Universitaetsplatz 1, 8010 Graz (Austria); Nermell, B. [Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm (Sweden)] [Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm (Sweden); Ekstroem, E.C. [Department of Women's and Children's Health, International Maternal and Child Health, Uppsala University, SE-751 85 Uppsala (Sweden)] [Department of Women's and Children's Health, International Maternal and Child Health, Uppsala University, SE-751 85 Uppsala (Sweden); Loennerdal, B. [Department of Nutrition, University of California, Davis, CA 95616 (United States)] [Department of Nutrition, University of California, Davis, CA 95616 (United States); El Arifeen, S. [International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), GPO Box 128, Dhaka 100 (Bangladesh)] [International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), GPO Box 128, Dhaka 100 (Bangladesh); Vahter, M., E-mail: Marie.Vahter@ki.se [Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm (Sweden)

    2009-10-15

    Experimental studies indicate that zinc (Zn) and calcium (Ca) status, in addition to iron (Fe) status, affect gastrointestinal absorption of cadmium (Cd), an environmental pollutant that is toxic to kidneys, bone and endocrine systems. The aim of this study was to evaluate how various nutritional factors influence the uptake of Cd in women, particularly during pregnancy. The study was carried out in a rural area of Bangladesh, where malnutrition is prevalent and exposure to Cd via food appears elevated. The uptake of Cd was evaluated by associations between erythrocyte Cd concentrations (Ery-Cd), a marker of ongoing Cd exposure, and concentrations of nutritional markers. Blood samples, collected in early pregnancy and 6 months postpartum, were analyzed by inductively coupled plasma mass spectrometry (ICPMS). Ery-Cd varied considerably (range: 0.31-5.4 {mu}g/kg) with a median of 1.1 {mu}g/kg (approximately 0.5 {mu}g/L in whole blood) in early pregnancy. Ery-Cd was associated with erythrocyte manganese (Ery-Mn; positively), plasma ferritin (p-Ft; negatively), and erythrocyte Ca (Ery-Ca; negatively) in decreasing order, indicating common transporters for Cd, Fe and Mn. There was no evidence of Cd uptake via Zn transporters, but the association between Ery-Cd and p-Ft seemed to be dependent on adequate Zn status. On average, Ery-Cd increased significantly by 0.2 {mu}g/kg from early pregnancy to 6 months postpartum, apparently due to up-regulated divalent metal transporter 1 (DMT1). In conclusion, intestinal uptake of Cd appears to be influenced either directly or indirectly by several micronutrients, in particular Fe, Mn and Zn. The negative association with Ca may suggest that Cd inhibits the transport of Ca to blood.

  4. Novel MntR-Independent Mechanism of Manganese Homeostasis in Escherichia coli by the Ribosome-Associated Protein HflX

    PubMed Central

    Kaur, Gursharan; Sengupta, Sandeepan; Kumar, Vineet; Kumari, Aruna; Ghosh, Aditi; Parrack, Pradeep

    2014-01-01

    Manganese is a micronutrient required for activities of several important enzymes under conditions of oxidative stress and iron starvation. In Escherichia coli, the manganese homeostasis network primarily constitutes a manganese importer (MntH) and an exporter (MntP), which are regulated by the MntR dual regulator. In this study, we find that deletion of E. coli hflX, which encodes a ribosome-associated GTPase with unknown function, renders extreme manganese sensitivity characterized by arrested cell growth, filamentation, lower rate of replication, and DNA damage. We demonstrate that perturbation by manganese induces unprecedented influx of manganese in ?hflX cells compared to that in the wild-type E. coli strain. Interestingly, our study indicates that the imbalance in manganese homeostasis in the ?hflX strain is independent of the MntR regulon. Moreover, the influx of manganese leads to a simultaneous influx of zinc and inhibition of iron import in ?hflX cells. In order to review a possible link of HflX with the ? phage life cycle, we performed a lysis-lysogeny assay to show that the Mn-perturbed ?hflX strain reduces the frequency of lysogenization of the phage. This observation raises the possibility that the induced zinc influx in the manganese-perturbed ?hflX strain stimulates the activity of the zinc-metalloprotease HflB, the key determinant of the lysis-lysogeny switch. Finally, we propose that manganese-mediated autophosphorylation of HflX plays a central role in manganese, zinc, and iron homeostasis in E. coli cells. PMID:24794564

  5. Cadmium plating replacements

    NASA Technical Reports Server (NTRS)

    Nelson, Mary J.; Groshart, Earl C.

    1995-01-01

    The Boeing Company has been searching for replacements to cadmium plate. Two alloy plating systems seem close to meeting the needs of a cadmium replacement. The two alloys, zinc-nickel and tin-zinc are from alloy plating baths; both baths are neutral pH. The alloys meet the requirements for salt fog corrosion resistance, and both alloys excel as a paint base. Currently, tests are being performed on standard fasteners to compare zinc-nickel and tin-zinc on threaded hardware where cadmium is heavily used. The Hydrogen embrittlement propensity of the zinc-nickel bath has been tested, and just beginning for the tin-zinc bath. Another area of interest is the electrical properties on aluminum for tin-zinc and will be discussed. The zinc-nickel alloy plating bath is in production in Boeing Commercial Airplane Group for non-critical low strength steels. The outlook is promising that these two coatings will help The Boeing Company significantly reduce its dependence on cadmium plating.

  6. Process for removing and detoxifying cadmium from scrap metal including mixed waste

    SciTech Connect

    Kronberg, J.W.

    1994-07-01

    Cadmium-bearing scrap from nuclear applications, such as neutron shielding and reactor control and safety rods, must usually be handled as mixed waste since it is radioactive and the cadmium in it is both leachable and highly toxic. Removing the cadmium from this scrap, and converting it to a nonleachable and minimally radioactive form, would greatly simplify disposal or recycling. A process now under development will do this by shredding the scrap; leaching it with reagents which selectively dissolve out the cadmium; reprecipitating the cadmium as its highly insoluble sulfide; then fusing the sulfide into a glassy matrix to bring its leachability below EPA limits before disposal. Alternatively, the cadmium may be recovered for reuse. A particular advantage of the process is that all reagents (except the glass frit) can easily be recovered and reused in a nearly closed cycle, minimizing the risk of radioactive release. The process does not harm common metals such as aluminum, iron and stainless steel, and is also applicable to non-nuclear cadmium-bearing scrap such as nickel-cadmium batteries.

  7. Manganese metallurgy review. Part II: Manganese separation and recovery from solution

    Microsoft Academic Search

    Wensheng Zhang; Chu Yong Cheng

    2007-01-01

    Various methods for manganese separation and recovery from solution are reviewed, which are potentially applicable to leach solutions of secondary manganese sources, particularly nickel laterite waste effluents. The main methods include solvent extraction, sulfide precipitation, ion exchange, hydroxide precipitation and oxidative precipitation. These methods are briefly compared and assessed for both purification of manganese solutions and recovery of manganese from

  8. Health and environmental testing of manganese exhaust products from use of methylcyclopentadienyl manganese tricarbonyl in gasoline

    Microsoft Academic Search

    G. D. Pfeifer; J. M. Roper; D. Dorman; D. R. Lynam

    2004-01-01

    This paper reviews recent research on the environmental effects of methylcyclopentadienyl manganese tricarbonyl (MMT), personal exposures to airborne Mn as a result of MMT use, chemical characterization of the manganese particulates emitted from the tailpipe and progress in developing a (PBPK) model for manganese in rodents.Recent studies show that manganese is emitted as a mixture of compounds with an average

  9. Manganese deficiency in sugar beet and the incorporation of manganese in the coating of pelleted seed

    Microsoft Academic Search

    R. F. Farley; A. P. Draycott

    1978-01-01

    Summary A laboratory study, three glasshouse tests and eight field experiments on commercial farms in East Anglia during 1972 to 1974 tested the effect of incorporating manganese in the coating of pelleted seed on the manganese nutrition and yield of sugar beet. The pelleting material readily absorbed manganese from solution but most of the manganese was held in plant-available forms.

  10. Cadmium hazard in silver brazing.

    PubMed

    Gan, S L; Tan, S H; Pinnagoda, J; Tan, K T

    1995-03-01

    This study evaluates the usage of cadmium-containing silver brazing alloys in Singapore and the potential cadmium hazard from its use. Of the 137 factories which responded to the survey questionnaire, only 28 (20.4%) carried out brazing. Of these, only 7 factories used cadmium-containing filler alloys. One hundred and six out of 123 workers from one of these factories had cadmium-in-blood concentrations exceeding 10 mcg/l. Thirty-one (29.2%) of the workers with excessive cadmium absorption had urinary beta-2 microglobulin levels exceeding 28 mcg/g creat. Workers in the other factories who were intermittently exposed had cadmium-in-blood concentrations of 10 mcg/l and below. PMID:7653980

  11. Manganese: brain transport and emerging research needs.

    PubMed

    Aschner, M

    2000-06-01

    Idiopathic Parkinson's disease (IPD) represents a common neurodegenerative disorder. An estimated 2% of the U.S. population, age 65 and older, develops IPD. The number of IPD patients will certainly increase over the next several decades as the baby-boomers gradually step into this high-risk age group, concomitant with the increase in the average life expectancy. While many studies have suggested that industrial chemicals and pesticides may underlie IPD, its etiology remains elusive. Among the toxic metals, the relationship between manganese intoxication and IPD has long been recognized. The neurological signs of manganism have received close attention because they resemble several clinical disorders collectively described as extrapyramidal motor system dysfunction, and in particular, IPD and dystonia. However, distinct dissimilarities between IPD and manganism are well established, and it remains to be determined whether Mn plays an etiologic role in IPD. It is particularly noteworthy that as a result of a recent court decision, methylcyclopentadienyl Mn tricarbonyl (MMT) is presently available in the United States and Canada for use in fuel, replacing lead as an antiknock additive. The impact of potential long-term exposure to low levels of MMT combustion products that may be present in emissions from automobiles has yet to be fully evaluated. Nevertheless, it should be pointed out that recent studies with various environmental modeling approaches in the Montreal metropolitan (where MMT has been used for more than 10 years) suggest that airborne Mn levels were quite similar to those in areas where MMT was not used. These studies also show that Mn is emitted from the tail pipe of motor vehicles primarily as a mixture of manganese phosphate and manganese sulfate. This brief review characterizes the Mn speciation in the blood and the transport kinetics of Mn into the central nervous system, a critical step in the accumulation of Mn within the brain, outlines the potential susceptibility of selected populations (e.g., iron-deficient) to Mn exposure, and addresses future research needs for Mn. PMID:10852840

  12. Iron accumulation and enhanced growth in transgenic lettuce plants expressing the iron- binding protein ferritin

    Microsoft Academic Search

    F. Goto; T. Yoshihara; H. Saiki

    2000-01-01

    We have produced transgenic lettuce plants accumulating the iron storage protein ferritin. The integration of the ferritin\\u000a gene and expression levels in leaves were examined by Southern- and Western-blot analysis, respectively. It was shown that\\u000a transgenic lettuce plants contained iron levels ranging from 1.2 to 1.7 times that of the control plants, however, the manganese\\u000a content in transgenic lettuce plants

  13. Manganese-enhanced MRI of rat brain based on slow cerebral delivery of manganese(II) with silica-encapsulated Mn x Fe(1-x) O nanoparticles.

    PubMed

    Chen, Wei; Lu, Fang; Chen, Chiao-Chi V; Mo, Kuan-Chi; Hung, Yann; Guo, Zhi-Xuan; Lin, Chia-Hui; Lin, Ming-Huang; Lin, Yu-Hsuan; Chang, Chen; Mou, Chung-Yuan

    2013-09-01

    In this work, we report a monodisperse bifunctional nanoparticle system, MIO@SiO2 -RITC, as an MRI contrast agent [core, manganese iron oxide (MIO); shell, amorphous silica conjugated with rhodamine B isothiocyanate (RITC)]. It was prepared by thermal decomposition and modified microemulsion methods. The nanoparticles with varying iron to manganese ratios displayed different saturated magnetizations and relaxivities. In vivo MRI of rats injected intravenously with MIO@SiO2-RITC nanoparticles exhibited enhancement of the T1 contrast in brain tissue, in particular a time-delayed enhancement in the hippocampus, pituitary gland, striatum and cerebellum. This is attributable to the gradual degradation of MIO@SiO2-RITC nanoparticles in the liver, resulting in the slow release of manganese(II) [Mn(II)] into the blood pool and, subsequently, accumulation in the brain tissue. Thus, T1-weighted contrast enhancement was clearly detected in the anatomic structure of the brain as time progressed. In addition, T2*-weighted images of the liver showed a gradual darkening effect. Here, we demonstrate the concept of the slow release of Mn(II) for neuroimaging. This new nanoparticle-based manganese contrast agent allows one simple intravenous injection (rather than multiple infusions) of Mn(II) precursor, and results in delineation of the detailed anatomic neuroarchitecture in MRI; hence, this provides the advantage of the long-term study of neural function. PMID:23526743

  14. Olfactory ferric and ferrous iron absorption in iron-deficient rats

    PubMed Central

    Ruvin Kumara, V. M.

    2012-01-01

    The absorption of metals from the nasal cavity to the blood and the brain initiates an important route of occupational exposures leading to health risks. Divalent metal transporter-1 (DMT1) plays a significant role in the absorption of intranasally instilled manganese, but whether iron uptake would be mediated by the same pathway is unknown. In iron-deficient rats, blood 59Fe levels after intranasal administration of the radioisotope in the ferrous form were significantly higher than those observed for iron-sufficient control rats. Similar results were obtained when ferric iron was instilled intranasally, and blood levels of 59Fe were even greater in the iron-deficient rats compared with the amount of ferrous iron absorbed. Experiments with Belgrade (b/b) rats showed that DMT1 deficiency limited ferric iron uptake from the nasal cavity to the blood compared with +/b controls matched for iron deficiency. These results indicate that olfactory uptake of ferric iron by iron-deficient rats involves DMT1. Western blot experiments confirmed that DMT1 levels are significantly higher in iron-deficient rats compared with iron-sufficient controls in olfactory tissue. Thus the molecular mechanism of olfactory iron absorption is regulated by body iron status and involves DMT1. PMID:22492739

  15. Removal of cadmium by combining deferasirox and desferrioxamine chelators in rats.

    PubMed

    Fatemi, S Jamilaldine; Saljooghi, Amir Shokooh; Balooch, Faezeh Dahooee; Iranmanesh, Marzieh; Golbafan, Mohammad Reza

    2012-02-01

    An investigation was conducted to evaluate the ability of two chelators, deferasirox and desferrioxamine (DFO), in removing cadmium from biological system. The potential efficiency of those chelators were investigated after cadmium administration for 60 days following two dose levels of 20 and 40 mg/kg body weight daily to male rats. However, abnormalities were observed in clinical signs after cadmium administration, such as yellowish discoloration of hair, flaccid and hypotonic muscles, irritability, weakness and loss of weight. The hypothesis that the two chelators might be more efficient as combined therapy than single therapy in removing metal ions from the body was considered. In this way, two known chelators, deferasirox and DFO were chosen and tested in the acute rat model. The chelation therapy results show that deferasirox and DFO are able (?)to remove cadmium ions from the body, while iron concentration returned to the normal level and symptoms are decreased. PMID:22134990

  16. Acquisition of Iron by Alkaliphilic Bacillus Species?

    PubMed Central

    McMillan, Duncan G. G.; Velasquez, Imelda; Nunn, Brook L.; Goodlett, David R.; Hunter, Keith A.; Lamont, Iain; Sander, Sylvia G.; Cook, Gregory M.

    2010-01-01

    The biochemical and molecular mechanisms used by alkaliphilic bacteria to acquire iron are unknown. We demonstrate that alkaliphilic (pH > 9) Bacillus species are sensitive to artificial iron (Fe3+) chelators and produce iron-chelating molecules. These alkaliphilic siderophores contain catechol and hydroxamate moieties, and their synthesis is stimulated by manganese(II) salts and suppressed by FeCl3 addition. Purification and mass spectrometric characterization of the siderophore produced by Caldalkalibacillus thermarum failed to identify any matches to previously observed fragmentation spectra of known siderophores, suggesting a novel structure. PMID:20802068

  17. Discovery of Cadmium, Indium, and Tin Isotopes

    NASA Astrophysics Data System (ADS)

    Amos, Stephanie; Thoennessen, Michael

    2009-10-01

    As of today, no comprehensive study has been made covering the initial observations and identifications of isotopes. A project has been undertaken at MSU to document the discovery of all the known isotopes. The criteria defining discovery of a given isotope is the publication of clear mass and element assignment in a refereed journal. Prior to the current work the documentation of the discovery of eleven elements had been completed^1. These elements are cerium^2, arsenic, gold, tungsten, krypton, silver, vanadium, einsteinium, iron, barium, and cobalt. We will present the new documentation for the cadmium, indium, and tin isotopes. Thirty-seven cadmium isotopes, thirty-eight indium isotopes, and thirty-eight tin isotopes have been discovered so far. The description for each discovered isotope includes the year of discovery, the article published on the discovery, the article's author, the method of production, the method of identification, and any previous information concerning the isotope discovery. A summary and overview of all ˜500 isotopes documented so far as a function of discovery year, method and place will also be presented. ^1http://www.nscl.msu.edu/˜thoennes/2009/discovery.htm ^2J.Q. Ginepro, J. Snyder, and M. Thoennessen, At. Data Nucl. Data. Tables, in press (2009), doi:10.1016/j.adt.2009.06.002

  18. Urinary cadmium and beta2-microglobulin: correlation with nutrition and smoking history (journal version)

    SciTech Connect

    Kowal, N.E.

    1988-01-01

    Urinary cadmium and beta2-microglobulin concentrations from approximately 1000 samples from the general adult U.S. population, collected as part of the National Health and Nutritional Examination Survey II (NHANES II), were related to nutritional and smoking history of the individuals. Urinary cadmium concentration was negatively correlated with dietary iron (significance level of 0.0065), negatively correlated with dietary calcium (significance level of less than 0.0001), and significantly (level of less than 0.001) higher in past or present smokers than in those who had never smoked. The results suggest increased cadmium absorption in the presence of low dietary intake of iron, low dietary intake of calcium, and cigarette smoking in the general population of the United States.

  19. Catalytic role of Manganese oxides in prebiotic Nucleobases synthesis from Formamide

    NASA Astrophysics Data System (ADS)

    Bhushan, Brij

    2012-07-01

    The evolution of living cell from chemicals is more complicated reaction which could be studied in multistep. A study of prebiotic synthesis of naturally occurring purine and pyrimidine derivatives from formamide under catalytic condition with different oxides of manganese reveals a significant role. Manganese oxides are highly efficient in the conversion of formamide into different nucleobases. Neat formamide is converted to the purine, 9-(hydroxyacetyl) purine, cytosine, 4(3H)-pyrimidinone, thymine and adenine in good yield. Metal oxides have provided their surfaces and catalyzed the reactions from simple molecules to more complex bio-organic molecules. Our results show that probably prebiotic reactions might have occured on the sea floor where the existence of manganese oxide is second to iron transition metal minerals.

  20. Synthesis, characterization, optical and sensing property of manganese oxide nanoparticles

    SciTech Connect

    Manigandan, R.; Suresh, R.; Giribabu, K.; Narayanan, V., E-mail: vnnara@yahoo.co.in [Department of Inorganic Chemistry, University of Madras, Guindy Campus, Chennai 600 025 (India); Vijayalakshmi, L. [Annai Veilankanni's College for Women (Arts and Science), Saidapet, Chennai 600015 (India); Stephen, A. [Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600 025 (India)

    2014-01-28

    Manganese oxide nanoparticles were prepared by thermal decomposition of manganese oxalate. Manganese oxalate was synthesized by reacting 1:1 mole ratio of manganese acetate and ammonium oxalate along with sodium dodecyl sulfate (SDS). The structural characterization of manganese oxalate and manganese oxide nanoparticles was analyzed by XRD. The XRD spectrum confirms the crystal structure of the manganese oxide and manganese oxalate. In addition, the average grain size, lattice parameter values were also calculated using XRD spectrum. Moreover, the diffraction peaks were broadened due to the smaller size of the particle. The band gap of manganese oxide was calculated from optical absorption, which was carried out by DRS UV-Visible spectroscopy. The morphology of manganese oxide nanoparticles was analyzed by SEM images. The FT-IR analysis confirms the formation of the manganese oxide from manganese oxalate nanoparticles. The electrochemical sensing behavior of manganese oxide nanoparticles were investigated using hydrogen peroxide by cyclic voltammetry.

  1. Isolation of iron bacteria from terrestrial and aquatic environments

    NASA Astrophysics Data System (ADS)

    Schmidt, Bertram; Szewzyk, Ulrich

    2010-05-01

    Bacteria, which are capable of iron oxidation or at least iron deposition are widely distributed in environments where zones of dissolved ferrous iron and oxygen gradients are overlapping [1]. They take part in the biological cycling of iron and influence other cycles of elements for example carbon [2]. Manganese can be used for similar metabolic purposes as iron, because it can be biologically oxidized by chemolithotrophs or can be reduced by respirating bacteria as well [3, 4]. Bacterial activity is responsible for the accumulation of ferric iron compounds in their surroundings. The formation of bog ore is a well known example for a soil horizon, with an extreme enrichment of biogenic ferric iron [5]. We focused on the isolation of neutrophilic iron bacteria and bacteria capable of manganese oxidation. We used samples from Tierra del Fuego (Argentina) the National Park "Unteres Odertal" (Germany) and Berlin ground water wells. Microscopic examination of the samples revealed a considerable diversity of iron encrusted structures of bacterial origin. Most of these morphologic types are already well known. The taxonomic classification of many of these organisms is based on morphologic features and is not reliable compared to recent methods of molecular biology. That is mainly due to the fact, that most of these bacteria are hardly culturable or do not show their characteristic morphologic features under culture conditions. We established a collection of more than 300 iron depositing strains. Phylogenetic analyses showed that we have many yet uncultured strains in pure culture. We obtained many isolates which form distinct branches within long known iron bacteria groups like the Sphaerotilus-Leptothrix cluster. But some of the strains belong to groups, which have not yet been associated with iron oxidation activity. The strains deposit high amounts of oxidized iron and manganese compounds under laboratory conditions. However it is unclear if these precipitations are due to biological oxidation or biological deposition of chemically oxidized iron. We examined the morphologic characteristics of selected isolates under near-natural conditions to assign them to morphologic structures which occur in native samples. Our aim for the future is to describe several strains. References: [1] Weber, K. A. ; Achenbach, L. A. ; Coates, J. D. : Microorganisms pumping iron: anaerobic microbial iron oxidation and reduction. In: Nature Reviews Microbiology 4 (2006) 752-764 [2] Van Capellen, P. ; Wang Y. : Cycling of iron and manganese in surface sediments: a general theory for the coupled transport and reaction of carbon, oxygen, nitrogen, sulfur, iron and manganese. In: American Journal of Science 296 (1996) 197-243 [3] Tebo, B. M. ; Bargar, J. R. ; Clement, B. G. ; Dick, G. J. ; Murray, K. J. ; Parker, D. Verity R. ; Webb, S. M. : Biogenic manganese oxides: properties and mechanisms of formation. In: Annual Reviews Earth Planet Science 32 (2004) 287-328 [4] Erlich, H. L. : Manganese oxide reduction as a form of anaerobic respiration. In: Geomicrobiology Journal 5 (1987) 423-431 [5] Ghiorse W. C. : Biology of iron- and manganese-depositing bacteria. In: Annual Reviews 38 (1984) 515-550

  2. The selective recovery of cadmium(II) from sulfate solutions by a counter-current extraction–stripping process using a mixture of diisopropylsalicylic acid and Cyanex® 471X

    Microsoft Academic Search

    L. Gotfryd; M. Cox

    2006-01-01

    The liquid–liquid extraction of cadmium(II) from solutions, obtained by leaching of deposited cadmium carbonate or cadmium cementation sponge and heavily contaminated with other components, especially zinc, has been studied. Initially the solutions were purified; iron and other contaminants were removed by oxyhydrolysis. An equimolar mixture of diisopropylsalicylic acid and Cyanex® 471X (0.5 mol\\/L\\/0.5 mol\\/L), diluted with Solvesso 150, was used

  3. Erosion-corrosion behavior of austenitic cast iron in an acidic slurry medium

    NASA Astrophysics Data System (ADS)

    Yang, Ke; Sun, Lan; Liu, Yu-zhen; Fan, Hong-yuan

    2015-06-01

    A series of austenitic cast iron samples with different compositions were cast and a part of nickel in the samples was replaced by manganese for economic reason. Erosion-corrosion tests were conducted under 2wt% sulfuric acid and 15wt% quartz sand. The results show that the matrix of cast irons remains austenite after a portion of nickel is replaced with manganese. (Fe,Cr)3C is a common phase in the cast irons, and nickel is the main alloying element in high-nickel cast iron; whereas, (Fe,Mn)3C is observed with the increased manganese content in low-nickel cast iron. Under erosion-corrosion tests, the weight-loss rates of the cast irons increase with increasing time. Wear plays a more important role than corrosion in determining the weight loss. It is indicated that the processes of weight loss for the cast irons with high and low nickel contents are different. The erosion resistance of the cast iron containing 7.29wt% nickel and 6.94wt% manganese is equivalent to that of the cast iron containing 13.29wt% nickel.

  4. Cadmium colours: composition and properties

    NASA Astrophysics Data System (ADS)

    Paulus, J.; Knuutinen, U.

    The composition and the properties of cadmium aquarelle colours are discussed. The examined colours were 24 different aquarelle cadmium colours from six different manufacturers. The colours ranged from light, bright yellows to dark, deep-red tones. The aim of this research was to find out if the pigments contain cadmium salts: sulphides and/or selenides. This information will help in choosing watercolours in conservation processes. Today, aquarelle colours not containing cadmium pigments are being sold as cadmium colours; thus their properties might be different from actual cadmium colours. The aim of the research was to verify that the colour samples contained cadmium pigments and to estimate their compositions and ageing properties. Element analyses were performed from colour samples using micro-chemical tests and X-ray fluorescence measurements. Thin-layer chromatography was used for analysing gum Arabic as a possible binding medium in the chosen colour samples. Through ageing tests, the resistance of the colour samples to the exposure to light, heat and humidity was studied. Visible-light spectroscopy was used in determining the hues and hue changes of the aquarelle colour samples. The spectrophotometer used the CIE L*a*b* tone colour measuring system. From the colour measurements the changes in the lightness/darkness, the redness, the yellowness and the saturation of the samples were examined.

  5. Electrical behavior of natural manganese dioxide (NMD)

    SciTech Connect

    Gorgulho, H.F. [Fundacao de Ensino Superior de Sao Joao del Rei, Minas Gerais (Brazil); Fernandes, R.Z.D.; Pernaut, J.M. [Univ. Federal de Minas Gerais, Belo Horizonte, Minas Gerais (Brazil)

    1996-12-31

    NMD samples from Brazil have been submitted to magnetic and particle size separations and characterized by X-ray diffraction and fluorescence and thermogravimetric analyses. Results showed that simple physical treatments can lead to more than 60% enriched MnO{sub 2} materials which could satisfy some electrochemical applications. The electrical properties of the samples conditioned as pressed pellets have been investigated by four-points direct current probe and impedance spectroscopy, varying the conditions of preparation and measurement. It is proposed that the higher frequency impedance is equivalent to the intrinsic electronic resistance of the MnO{sub 2} phases while at lower frequencies occurs an interphase charge separation coupled with a possible ionic transport. The corresponding contact resistance depends on the particle size distribution of the material, the compactation pressure of pellets and the iron content of the materials. The interphase dielectric relaxation does not behave ideally; the depression of the impedance semicircles as shown in the Nyquist plane is assumed to be related to the roughness of the bulk interfaces. Recent developments have shown the possibility of using manganese oxides as reversible electrodes for battery or supercapacitor applications for electrical vehicle. In these perspectives it is important to study the electrical and electrochemical properties of NMD in order to estimate its suitability for this kind of applications.

  6. Cadmium and mercury nephrotoxicity

    NASA Astrophysics Data System (ADS)

    Nicholson, J. K.

    1983-08-01

    Despite increasing attempts to control environmental pollution, changes in the distribution and bioavailability of toxic metals like mercury and cadmium are still occurring. Apart from natural processes, other contributory factors include the gradual spread of industrialization, the use of sewage sludge as a fertilizer and the acidification of Northern Hemisphere ground-water. Animals (including man and domestic varieties) can accumulate harmful concentrations of toxic metals1-5. We therefore looked for damage to the kidneys in seabirds contaminated with mercury and cadmium and made comparisons with kidneys from three other groups of animals: seabirds from an uncontaminated colony, metal-dosed birds and metal-dosed mice. We report here that, comparing all these groups of animals, invididuals with comparatively high levels of metals had nephrotoxic lesions of a similar type and severity. Moreover, the metal concentrations at which damage began and at which biochemical changes could be detected were below those presently considered as relatively safe for humans by the World Health Organization.

  7. Intoxication aigu et chronique au cadmium Acute and chronic cadmium poisoning

    E-print Network

    Paris-Sud XI, Université de

    poisoning Summary (176 words): Key words : cadmium - poisoning - pneumonia - nephropathy - osteomalacia of osteomalacia and diffuse osteoporosis. Cadmium is classified as certain carcinogen agent for humans by IARC

  8. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Barium calcium manganese strontium oxide. 721.10011...Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a...chemical substance identified as barium calcium manganese strontium oxide (PMN...

  9. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Barium calcium manganese strontium oxide. 721.10011...Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a...chemical substance identified as barium calcium manganese strontium oxide (PMN...

  10. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Barium calcium manganese strontium oxide. 721.10011...Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a...chemical substance identified as barium calcium manganese strontium oxide (PMN...

  11. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Barium calcium manganese strontium oxide. 721.10011...Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a...chemical substance identified as barium calcium manganese strontium oxide (PMN...

  12. Manganese deficiency and toxicity: are high or low dietary amounts of manganese cause for concern?

    PubMed

    Finley, J W; Davis, C D

    1999-01-01

    Manganese is an essential trace element that is required for the activity of several enzymes. Manganese is also quite toxic when ingested in large amounts, such as the inhalation of Mn-laden dust by miners. This review examines Mn intake by way of the food supply and poses the question: Is there reason to be concerned with Mn toxicity or deficiency in free-living populations in North America? Although much remains to be learned of the functions of Mn, at present there are only a few vaguely described cases of Mn deficiency in the medical literature. Given the heterogeneity of the North American food supply, it is difficult to see the possibility of more than greatly isolated and unique instances of Mn deficiency. However, low Mn-dependent superoxide dismutase activity may be associated with cancer susceptibility, and deserves further study. There may be reasons, however, to be concerned about Mn toxicity under some very specialized conditions. Increasing numbers of young people are adopting a vegetarian lifestyle which may greatly increase Mn intake. Iron deficiency may increase Mn absorption and further increase the body-burden of Mn, especially in vegetarians. Mn is eliminated primarily through the bile, and hepatic dysfunction could depress Mn excretion and further contribute to the body burden. Would such a combination of events predispose substantial numbers of people to chronic Mn toxicity? At present, there is no definite proof of this occurring, but given the state of knowledge at the present time, more studies with longer time-frames and more sensitive methods of analysis are needed. PMID:10475586

  13. Methylcyclopentadienyl Manganese Tricarbonyl: Effect on Manganese Emissions from Vehicles on the Road

    Microsoft Academic Search

    William R. Pierson; Douglas E. McKee; Wanda W. Brachaczek; James W. Butler

    1978-01-01

    This note describes some measurements of manganese concentrations and manganese emission rates, categorized as to vehicle type, from cars and trucks at two tunnels on the Pennsylvania Turnpike. These measurements were made during the period that methylcyclopentadienyl manganese tricarbonyl (MMT) came into use as an alternative to organo-lead compounds for improving combustion in gasoline engines.

  14. Discovery of the Cadmium Isotopes

    E-print Network

    S. Amos; M. Thoennessen

    2009-10-22

    Thirty-seven cadmium isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  15. Negative impact of manganese on honeybee foraging.

    PubMed

    Søvik, Eirik; Perry, Clint J; LaMora, Angie; Barron, Andrew B; Ben-Shahar, Yehuda

    2015-03-01

    Anthropogenic accumulation of metals such as manganese is a well-established health risk factor for vertebrates. By contrast, the long-term impact of these contaminants on invertebrates is mostly unknown. Here, we demonstrate that manganese ingestion alters brain biogenic amine levels in honeybees and fruit flies. Furthermore, we show that manganese exposure negatively affects foraging behaviour in the honeybee, an economically important pollinator. Our findings indicate that in addition to its direct impact on human health, the common industrial contaminant manganese might also have indirect environmental and economical impacts via the modulation of neuronal and behavioural functions in economically important insects. PMID:25808001

  16. Incommensurately Modulated Cadmium Apatites

    NASA Astrophysics Data System (ADS)

    Henning, Peter Alberius; Moustiakimov, Marat; Lidin, Sven

    2000-02-01

    Two cadmium apatites, Cd5(PO4)3Br and Cd5(VO4)3I, earlier reported to be halogenide deficient, were prime suspects of being modulated. In this study, incommensurate ordering was found in satellites occurring in planes perpendicular to c*. The structure of Cd5(PO4)3Br was refined from single-crystal X-ray diffraction data in the four-dimensional super space group R=Poverline3:(00?): a=16.932(2) Å, c=6.451(1) Å, Z=6, R=0.043. The modulation of the structure is due to a misfit between the large halogenide ions and the surrounding rigid Ca-PO4 substructure. From the refined model of the Cd5(PO4)3Br structure a "chain-packing" model was confirmed with a Br-Br distance of 3.466 Å.

  17. Iron in Brain Function and Dysfunction with Emphasis on Parkinson’s Disease

    Microsoft Academic Search

    M. B. H. Youdim; D. Ben-Shachar; P. Riederer

    1991-01-01

    Metals such as lead, zinc, copper, aluminum and manganese have been implicated in neuropsychiatric disorders. However, until fairly recently the role of iron in brain function was rather obscure, because little attention was paid to its metabolism in the brain. It is now apparent that maintenance of brain iron homoeostasis is important for the normal functioning of his organ. Most

  18. Unusual calibration curves observed for iron using high-resolution continuum source graphite furnace atomic absorption spectrometry

    Microsoft Academic Search

    Bernhard Welz; Lísia M. G. dos Santos; Rennan G. O. Araujo; Silvana do C. Jacob; Maria Goreti R. Vale; Michael Okruss; Helmut Becker-Ross

    2010-01-01

    The simultaneous determination of cadmium and iron in plant and soil samples has been investigated using high-resolution continuum source graphite furnace atomic absorption spectrometry. The primary cadmium resonance line at 228.802nm and an adjacent secondary iron line at 228.726nm, which is within the spectral interval covered by the charge-coupled device (CCD) array detector, have been used for the investigations. Due

  19. Manganese(III) binding to a pyoverdine siderophore produced by a manganese(II)-oxidizing bacterium

    NASA Astrophysics Data System (ADS)

    Parker, Dorothy L.; Sposito, Garrison; Tebo, Bradley M.

    2004-12-01

    The possible roles of siderophores (high affinity chelators of iron(III)) in the biogeochemistry of manganese remain unknown. Here we investigate the interaction of Mn(III) with a pyoverdine-type siderophore (PVD MnB1) produced by the model Mn(II)-oxidizing bacterium Pseudomonas putida strain MnB1. PVD MnB1 confirmed typical pyoverdine behavior with respect to: (a) its absorption spectrum at 350-600 nm, both in the absence and presence of Fe(III), (b) the quenching of its fluorescence by Fe(III), (c) the formation of a 1:1 complex with Fe(III), and (d) the thermodynamic stability constant of its Fe(III) complex. The Mn(III) complex of PVD MnB1 had a 1:1 Mn:pvd molar ratio, showed fluorescence quenching, and exhibited a light absorption spectrum (A max = 408-410 nm) different from that of either PVD MnB1-Fe(III) or uncomplexed PVD MnB1. Mn(III) competed strongly with Fe(III) for binding by PVD MnB1 in culture filtrates (pH 8, 4°C). Equilibration with citrate, a metal-binding ligand, did not detectably release Mn from its PVD MnB1 complex at a citrate/PVD MnB1 molar ratio of 830 (pH 8, 4°C), whereas pyrophosphate under the same conditions removed 55% of the Mn from its PVD MnB1 complex. Most of the PVD MnB1-complexed Mn was released by reaction with ascorbate, a reducing agent, or with EDTA, a ligand that is also oxidized by Mn(III). Data on the competition for binding to PVD MnB1 by Fe(III) vs. Mn(III) were used to determine a thermodynamic stability constant (nominally at 4°C) for the neutral species MnHPVD MnB1 (log K = 47.5 ± 0.5, infinite dilution reference state). This value was larger than that determined for FeHPVD MnB1 (log K = 44.6 ± 0.5). This result has important implications for the metabolism, solubility, speciation, and redox cycling of manganese, as well as for the biologic uptake of iron.

  20. Cadmium uptake from cadmium-spiked sediments by four freshwater invertebrates

    Microsoft Academic Search

    Bruce W. Kilgour

    1991-01-01

    In an attempt to identify other organisms that may be useful for assessing the pollution status of freshwater sediments, cadmium concentrations of four common benthic organisms exposed to cadmium-spiked sediments were examined. Organisms that accumulate cadmium to relatively higher levels are the most useful for analysis and detection. Further, organisms that have body concentrations of cadmium that are more highly

  1. Solubilization of plutonium hydrous oxide by iron-reducing bacteria

    Microsoft Academic Search

    Patricia A. Rusin; Leticia Quintana; James R. Brainard; B. A. Strietelmeler; C. Drew Tait; Scott A. Ekberg; Phillip D. Palmer; Thomas W. Newton; David L. Clark

    1994-01-01

    The removal of plutonium from soils id challenging because of its strong sorption to soils and limited solubility, Microbial reduction of metals is known to affect the speciation and solubility of sparingly soluble metals in the environment, notably iron and manganese. The similarity in reduction potential for [alpha]-FeOOH(s) and hydrous PuO[sub 2](s) suggests that iron-reducing bacteria may also reduce and

  2. Comparative pneumotoxicity of cyclopentadienyl manganese tricarbonyl and methylcyclopentadienyl manganese tricarbonyl.

    PubMed

    Clay, R J; Morris, J B

    1989-05-01

    The acute pneumotoxic effects of cyclopentadienyl manganese tricarbonyl (CMT) and methylcyclopentadienyl manganese tricarbonyl (MMT) were compared to delineate the role of the methyl side chain in the toxicity of these organomanganese compounds and to further our understanding of the mechanisms by which these compounds act. Specifically, lung manganese (Mn) burdens and the pneumotoxic response, as measured by bronchoalveolar lavage parameters, were determined in male Sprague-Dawley rats 24 hr after sc administration of 0.5, 1.0, or 2.5 mg Mn/kg as CMT or MMT. The pneumotoxic response to either compound was characterized by large increases in lavage albumin and protein content with smaller increases in lactate dehydrogenase levels. CMT was approximately twice as potent as MMT. This difference in potency may be due to methyl side chain oxidation, a metabolic detoxification pathway unavailable to CMT. Lung Mn content was significantly elevated after treatment with either CMT or MMT. Heptane extraction studies revealed that Mn was accumulated in a nonlipid soluble form, suggesting the accumulation of metabolites rather than heptane soluble parent MMT or CMT. A strong correlation between pulmonary Mn content and toxicity was observed, suggesting a causal relationship between the accumulation of CMT or MMT metabolites and toxicity. Piperonyl butoxide diminished both the pneumotoxicity and Mn accumulation resulting from CMT or MMT, suggesting both phenomena are due to monooxygenase metabolites. Pulmonary nonprotein sulfhydryl (NPSH) levels were increased twofold 24 hr after administration of either CMT or MMT. Depletion of NPSH was not observed 1.5 or 6 hr after administration. The mechanisms of this response are unclear but may be due to the metabolism of CMT or MMT to unstable compounds which release inorganic Mn within pulmonary cells. PMID:2718172

  3. Unusually high intake and fecal output of cadmium, and fecal output of other trace elements in New Zealand adults consuming dredge oysters. [Tiostrea lutaria

    SciTech Connect

    McKenzie-Parnell, J.M.; Kjellstrom, T.E.; Sharma, R.P.; Robinson, M.F.

    1988-06-01

    The concentration of cadmium in New Zealand dredge oyster Tiostrea lutaria (commonly known as a Bluff oyster) is sufficiently high so that the ingestion of just one oyster can more than double a normal daily intake of cadmium for a New Zealand adult. A survey of 75 adults associated with the oyster fishing industry was carried out before and at the end of the oyster season. Preseason intakes (from dietary history questionnaires and from 3-day fecal collections) of cadmium, selenium, zinc, copper, and manganese were normal for a New Zealand adult not consuming Bluff oysters. The subjects were classified according to their reported average oyster consumption during the 6 months of the oyster fishing season; the subjects who consumed more oysters were more likely to smoke cigarettes. The end-season fecal output of cadmium confirmed the reported average oyster intakes: Category I (0-5 oysters/week): 15 +/- 8 (mean +/- SD) ..mu..g Cd/day; Category II (6-23 oysters/week): 84 +/- 134 ..mu..g Cd/day; Category III (24-71 oysters/week): 129 +/- 144 ..mu..g Cd/day; Category IV (72 + oysters/week): 233 +/- 185 ..mu..g Cd/day. The fecal output of selenium as well was increased by the consumption of many oysters but the fecal outputs of zinc, copper, manganese were not. Using fecal cadmium excretion to predict dietary cadmium intake, 8-15% of the subjects in this study were identified as having an intake of cadmium which has been associated with an increased prevalence of tubular proteinuria.

  4. Manganese inhibition of microbial iron reduction in anaerobic sediments

    Microsoft Academic Search

    Derek R. Lovley; Elizabeth J. P. Phillips

    1988-01-01

    Potential mechanisms for the lack of Fe(II) accumulation in Mn(IV)?con?taining anaerobic sediments were investigated. The addition of Mn(IV) to sediments in which Fe(III) reduction was the terminal electron?accepting process removed all the pore?water Fe(II), completely inhibited net Fe(III) reduction, and stimulated Mn(IV) reduction. In a solution buffered at pH 7, Mn(IV) oxidized Fe(II) to amorphic Fe(III) oxide. Mn(IV) naturally present

  5. Structural studies of iron and manganese in photosynthetic reaction centers

    Microsoft Academic Search

    1987-01-01

    Electron paramagnetic resonance (EPR) and x-ray absorption spectroscopy (XAS) were used to characterize components involved in the light reactions of photosynthetic reaction centers from spinach and a thermophilic cyanobacterium, Synechococcus sp.: center X, the low electron potential acceptor in Photosystem I (PS I) and the Mn complex involved in water oxidation and oxygen evolution. The dependence of its EPR amplitude

  6. Microbial reduction of manganese oxides: Interactions with iron and sulfur

    Microsoft Academic Search

    C. R. Myers; K. H. Nealson

    1988-01-01

    Alteromonas putrefaciens (strain MR-1) is capable of rapid Mn(IV) reduction under conditions of neutral pH and temperatures characteristic of the Oneida Lake, New York, sediments from which it was isolated. MR-1 also reduces Fe{sup 3+} to Fe{sup 2+}, and disproportionates thiosulfate to sulfide and sulfite; independently, the Fe{sup 2+} and sulfide act as rapid reductants of Mn. The addition of

  7. Elevated levels of iron in groundwater in Prey Veng province in Cambodia: a possible factor contributing to high iron stores in women.

    PubMed

    Karakochuk, Crystal D; Murphy, Heather M; Whitfield, Kyly C; Barr, Susan I; Vercauteren, Suzanne M; Talukder, Aminuzzaman; Porter, Keith; Kroeun, Hou; Eath, Many; McLean, Judy; Green, Timothy J

    2015-06-01

    Iron is a natural element found in food, water and soil and is essential for human health. Our aim was to determine the levels of iron and 25 other metals and trace elements in groundwater from 22 households in Prey Veng, Cambodia. Water analyses were conducted using inductively coupled plasma-mass spectrometry and optical emission spectrometry. Compared to the 2011 World Health Organization guidelines for drinking water quality, aluminum, iron and manganese exceeded maximum levels (in 4.5, 72.7 and 40.9% of samples, respectively). Compared to the 2004 Cambodian drinking water quality standards, iron and manganese exceeded maximum levels (in 59.1 and 36.4% of samples, respectively). We found no evidence of arsenic contamination. Guidelines for iron were established primarily for esthetic reasons (e.g. taste), whereas other metals and elements have adverse effects associated with toxicity. Iron in groundwater ranged from 134 to 5,200 ?g/L (mean ?1,422 ?g/L). Based on a daily consumption of 3 L groundwater, this equates to ?0.4-15.6 mg iron (mean ?4.3 mg/day), which may be contributing to high iron stores and the low prevalence of iron deficiency anemia in Prey Veng women. Elevated levels of manganese in groundwater are a concern and warrant further investigation. PMID:26042988

  8. Globally sustainable manganese metal production and use

    Microsoft Academic Search

    Karen Hagelstein

    2009-01-01

    The “cradle to grave” concept of managing chemicals and wastes has been a descriptive analogy of proper environmental stewardship since the 1970s. The concept incorporates environmentally sustainable product choices—such as metal alloys utilized steel products which civilization is dependent upon. Manganese consumption is related to the increasing production of raw steel and upgrading ferroalloys. Nonferrous applications of manganese include production

  9. Original article Intestinal transfer of manganese

    E-print Network

    Paris-Sud XI, Université de

    Original article Intestinal transfer of manganese: resemblance to and competition with calcium Y of calcium, phosphate and the sugars lactose and sorbitol on the intestinal absorption of manganese were by this high calcium concentration. Intestinal alkaline phosphatase activity was rapidly stimulated by Mn

  10. UPTAKE OF HEAVY METALS IN BATCH SYSTEMS BY A RECYCLED IRON-BEARING MATERIAL

    EPA Science Inventory

    An iron-bearing material deriving from surface finishing operations in the manufacturing of cast-iron components demonstrates potential for removal of heavy metals from aqueous waste streams. Batch isotherm and rate experiments were conducted for uptake of cadmium, zinc, and lead...

  11. Selective removal of iron contaminations from zinc-chloride melts by cementation with zinc

    Microsoft Academic Search

    R. A. Devilee; A. van Sandwijk; M. A. Reuter

    1999-01-01

    An investigation into the cementation of iron chloride from a zinc-chloride melt at 400 °C has been carried out with zinc powder. The variables studied include preparation of the chloride melt and the amount of zinc added. The effect of lead, copper, and cadmium on cementation of iron has also been investigated. According to the results, it is possible to

  12. Mechanisms of alleviation of Zn, Cd, V, Ni and Co toxicities by dietary iron

    Microsoft Academic Search

    T. L. Blalock; C. H. Hill

    1986-01-01

    Previous studies from this laboratory have demonstrated that supplemental dietary iron (Fe), i.e. 1000 ppm, ameliorated zinc (Zn), cadmium (Cd), vanadium (V), nickel (Ni), and cobalt (Co) toxicities in chicks. Investigations into the mechanisms of this detoxification have been conducted. Chicks were fed diets containing 10, 110 or 1010 ppm iron along with 0 or 4000 ppm Zn, 0 or

  13. Cadmium oxide as electrochemical probe for nitrophenols

    Microsoft Academic Search

    K. Giribabu; R. Suresh; V. Narayanan; L. Vijayalakshmi; A. Stephen

    2011-01-01

    Cadmium oxide was synthesized using cadmium acetate and oleic acid as the precursors. The formed cadmium oxide nanoparticles were characterized by using XRD and cyclic voltammetry. The electrochemical detection of pollutants [4-Nitrophenol(4-NP) and 2-Nitrophenol(2-NP)] was carried out by coating the cadmium oxide onto the glassy carbon electrode (GCE) by drop coating method. The electrocatalytic performance of the modified GCE electrode

  14. Metallothionein and bioaccumulation of cadmium in juvenile bluegills exposed to aqueous and sediment-associated cadmium

    SciTech Connect

    Cope, W.G.

    1991-01-01

    The author evaluated metallothionein (MT), free (unbound) hepatic cadmium and whole body cadmium as indicators of cadmium exposure in juvenile bluegills Lepomis macrochirus in laboratory tests. Two types of cadmium exposure were tested; aqueous and sediment-associated. In the aqueous tests, fish were exposed to cadmium (0.0 to 32.3 [mu]g/L) in an intermittent-flow diluter. In the sediment-associated cadmium test, fish were exposed to resuspended river sidment containing 1.3 to 21.4 [mu]g Cd/g (dry weight) at a nominal total suspended solids concentration of 1,000 mg/L in revolving, circular glass exposure chambers. Total cadmium concentrations were measured in various bluegill liver fractions, whole bluegill, water, and resuspended sediment to assess the partitioning and bioaccumulation of cadmium after the tests. Mean concentrations of MT and free cadmium in bluegill livers and concentrations of cadmium in whole bluegills were positively correlated with aqueous cadmium concentration and were equally suitable as indicators of aqueous cadmium exposure. Sediment-associated cadmium was biologically available, but to a lesser extent than aqueous cadmium. Cadmium concentrations in whole bluegills exposed to resuspended river sediment were 1.5- to 3.5-fold the concentrations in bluegills in sediment-free controls. Free cadmium and MT concentrations in bluegill liver and whole-body cadmium concentrations in bluegills were positively correlated with the cadmium concentrations in filtered water, resuspended sediment, and bulk river sediment; however, whole-body cadmim concentrations were a more sensitive indicator of exposure to sediment-associated cadmium than either free cadmium or MT concentratons in liver.

  15. Leaching behavior of cadmium from hazardous waste

    Microsoft Academic Search

    Mahdi Gharabaghi; Mehdi Irannajad; Amir Reza Azadmehr

    Solid residues from hydrometallurgical zinc plants contain high concentrations of heavy metals such as zinc, cadmium and nickel, and these residues are considered as hazardous waste. Recovery of cadmium from this waste using sulfuric acid leaching has been studied. It was found that the cadmium extraction rate increased by increasing acid concentration, stirring speed and temperature and decreasing solid-to-liquid ratio

  16. Cadmium Removal from Contaminated Soil by Tunable

    E-print Network

    Chen, Wilfred

    Cadmium Removal from Contaminated Soil by Tunable Biopolymers G I R I D H A R P R A B H U K U M A R cadmium from contaminated soil. The stability constant (log KL) for the cadmium-ELPH12 complex as an effective extractant for heavy metal removal from contaminated soil or ore processing. Introduction Soil

  17. TREMOR, OLFACTORY AND MOTOR CHANGES IN ITALIAN ADOLESCENTS EXPOSED TO HISTORICAL FERRO-MANGANESE EMISSION

    PubMed Central

    Lucchini, Roberto G; Guazzetti, Stefano; Zoni, Silvia; Donna, Filippo; Peter, Stephanie; Zacco, Annalisa; Salmistraro, Marco; Bontempi, Elza; Zimmerman, Neil J; Smith, Donald R

    2012-01-01

    Background and Objective Increased prevalence of Parkinsonism was observed in Valcamonica, Italy, a region impacted by ferroalloy plants emissions containing manganese and other metals for a century until 2001. The aim of this study was to assess neurobehavioral functions in adolescents from the impacted region and the reference area of Garda Lake. Methods Adolescents age 11–14 yrs were recruited through the school system for neuro-behavioral testing. Metals including manganese, lead, iron, zinc, copper were measured in airborne particulate matter collected with 24-hour personal samplers, and in soil, tap water, blood, urine and hair. Independent variables included parental education and socio-economic status, children’s body mass index, number of siblings, parity order, smoking and drinking habits. Results A total of 311 subjects (49.2% females), residing in either the exposed (n=154) or the reference (n=157) area participated. Average airborne and soil manganese were respectively 49.5 ng/m3 (median 31.4, range 1.24–517) and 958 ppm (median 897, range 465–1729) in the impacted area, and 27.4 ng/m3 (median 24.7, range 5.3–85.9) ng/m3 and 427 ppm (median 409 range 160–734) in the reference area. Regression models showed significant impairment of motor coordination (Luria-Nebraska test, p=0.0005), hand dexterity (Aiming Pursuit test, p= 0.0115) and odor identification (Sniffin’ task, p=0.003 ) associated with soil manganese. Tremor intensity was positively associated with blood (p=0.005) and hair (p=0.01) manganese. Conclusion Historical environmental exposure to manganese from ferroalloy emission reflected by the concentration in soil and the biomarkers was associated with subclinical deficits in olfactory and motor function among adolescents. PMID:22322213

  18. Manganese borohydride; synthesis and characterization.

    PubMed

    Richter, Bo; Ravnsbæk, Dorthe B; Tumanov, Nikolay; Filinchuk, Yaroslav; Jensen, Torben R

    2015-03-01

    Solvent-based synthesis and characterization of ?-Mn(BH4)2 and a new nanoporous polymorph of manganese borohydride, ?-Mn(BH4)2, via a new solvate precursor, Mn(BH4)2·1/2S(CH3)2, is presented. Manganese chloride is reacted with lithium borohydride in a toluene/dimethylsulfide mixture at room temperature, which yields halide and solvent-free manganese borohydride after extraction with dimethylsulfide (DMS) and subsequent removal of residual solvent. This work constitutes the first example of establishing a successful, reproducible solvent-based synthesis route for a pure, crystalline, stable transition metal borohydride. The new polymorph, ?-Mn(BH4)2, is shown to be the manganese counterpart of the zeolite-like compound, ?-Mg(BH4)2 (cubic, a = 16.209(1) Å, space group Id3?a). It is verified that large pores (diameter > 6.0 Å) exist in this structure. The solvate, Mn(BH4)2·1/2S(CH3)2, is subsequently shown to be the analogue of Mg(BH4)2·1/2S(CH3)2. As the structural analogies between Mg(BH4)2 and Mn(BH4)2 became evident a new polymorph of Mg(BH4)2 was identified and termed ?-Mg(BH4)2. ?-Mg(BH4)2 is the structural counterpart of ?-Mn(BH4)2. All synthesis products are characterized employing synchrotron radiation-powder X-ray diffraction, infrared spectroscopy and thermogravimetric analysis in combination with mass spectroscopy. Thermal analysis reveals the decomposition of Mn(BH4)2 to occur at 160 °C, accompanied by a mass loss of 14.8 wt%. A small quantity of the desorbed gaseous species is identified as diborane (?(m)(Mn(BH4)2) = 9.5 wt% H2), while the remaining majority is found to be hydrogen. PMID:25611294

  19. Manganese and the Evolution of Photosynthesis

    NASA Astrophysics Data System (ADS)

    Fischer, Woodward W.; Hemp, James; Johnson, Jena E.

    2015-05-01

    Oxygenic photosynthesis is the most important bioenergetic event in the history of our planet—it evolved once within the Cyanobacteria, and remained largely unchanged as it was transferred to algae and plants via endosymbiosis. Manganese plays a fundamental role in this history because it lends the critical redox behavior of the water-oxidizing complex of photosystem II. Constraints from the photoassembly of the Mn-bearing water-oxidizing complex fuel the hypothesis that Mn(II) once played a key role as an electron donor for anoxygenic photosynthesis prior to the evolution of oxygenic photosynthesis. Here we review the growing body of geological and geochemical evidence from the Archean and Paleoproterozoic sedimentary records that supports this idea and demonstrates that the oxidative branch of the Mn cycle switched on prior to the rise of oxygen. This Mn-oxidizing phototrophy hypothesis also receives support from the biological record of extant phototrophs, and can be made more explicit by leveraging constraints from structural biology and biochemistry of photosystem II in Cyanobacteria. These observations highlight that water-splitting in photosystem II evolved independently from a homodimeric ancestral type II reaction center capable of high potential photosynthesis and Mn(II) oxidation, which is required by the presence of homologous redox-active tyrosines in the modern heterodimer. The ancestral homodimer reaction center also evolved a C-terminal extension that sterically precluded standard phototrophic electron donors like cytochrome c, cupredoxins, or high-potential iron-sulfur proteins, and could only complete direct oxidation of small molecules like Mn2+, and ultimately water.

  20. Mechanisms of cadmium carcinogenesis

    SciTech Connect

    Joseph, Pius [Molecular Carcinogenesis Laboratory, Toxicology and Molecular Biology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV (United States)], E-mail: pjoseph1@cdc.gov

    2009-08-01

    Cadmium (Cd), a heavy metal of considerable occupational and environmental concern, has been classified as a human carcinogen by the International Agency for Research on Cancer (IARC). The carcinogenic potential of Cd as well as the mechanisms underlying carcinogenesis following exposure to Cd has been studied using in vitro cell culture and in vivo animal models. Exposure of cells to Cd results in their transformation. Administration of Cd in animals results in tumors of multiple organs/tissues. Also, a causal relationship has been noticed between exposure to Cd and the incidence of lung cancer in human. It has been demonstrated that Cd induces cancer by multiple mechanisms and the most important among them are aberrant gene expression, inhibition of DNA damage repair, induction of oxidative stress, and inhibition of apoptosis. The available evidence indicates that, perhaps, oxidative stress plays a central role in Cd carcinogenesis because of its involvement in Cd-induced aberrant gene expression, inhibition of DNA damage repair, and apoptosis.

  1. Pressure Effects on Magneto-Optical Properties in Cadmium Telluride/(Cadmium, Manganese) Telluride Single Quantum Well with High Manganese Concentration

    SciTech Connect

    Yokoi, H.; Tozer,S.; Kim, Y.; Rickel, D.; Kakudate, Y.; Usuba, S.; Fujiwara, S.; Takeyama, S.; Karczewski, G.; Wojtowicz, T.; Kossut, J.

    1998-11-09

    The pressure effect on the magnetic field induced type I-type II transition is studied in a CdTe/Cd1-xMnxTe (x=0.24) single quantum well (SQW). Photoluminescence (PL) measurements under hydrostatic pressures up to 1.07 GPa and long pulsed magnetic fields up to 60 T with a pulse duration of 2 sec are reported. The pressures were generated in a plastic diamond anvil cell (DAC). A bend toward lower energies (additional red shift) is observed above 28.5 T in magnetic field dependence of the exciton energy for a 13 Aring thick quantum well. We attribute this red shift to a phenomenon preceding the type I-type II transition after a comparison with a simple quantum mechanical calculation. The onset field of the additional red shift increases by 3.4 T by applying a pressure of 1.07 GPa. Spin-spin coupling between the exciton and the Mn ion in the interface region is also investigated and found to be enhanced by pressure.

  2. Hydrogenation of CO and CO 2 with K and Mn promoted iron catalysts

    Microsoft Academic Search

    M. L. Cubeiro; G. Valderrama; M. R. Goldwasser; F. González-Jiménez; M. C. Da Silva; M. J. Pérez-Zurita

    1997-01-01

    Two iron catalysts promoted with potassium and manganese: FeKMn\\/Al2O3 and KMn\\/Laterite were tested in the H2+CO and H2+CO2 reactions at 563K, 1.3 MPa and various space velocities. Bulk iron phases were analysed by Mössbauer spectroscopy before and after reaction. After a reduction and carburation pre-treatment a higher proportion of carbided iron was attained for the laterite based solid compared to

  3. Manganese in Texas Soils and its Relation to Crops. 

    E-print Network

    Carlyle, E. C. (Elmer Cardinal)

    1931-01-01

    , and by Schreiner and Damison (15) in testing for deficiency of manganese in the glade soils of Florida. 10 BULLETIN NO. 432. TEXAS AGRICULTURAL EXPERIMENT STATION Method for Pot Experiments Glazed earthenware pots of two gallons capacity were used in this work... pouncls. Rye without manganese bage ldecl lfate I nn cal- nat- )en- ?nn- ob- eat, ~eri- sul- tin : MANGANESE IN TEXAS SOILS AND ITS RELATION TO CROPS 9 yieldecl 3456 pouncls per acre; with manganese, 3424 pounds. Corn without manganese...

  4. [Tongue play and manganese deficiency in dairy cattle].

    PubMed

    Karatzias, H; Roubies, N; Polizopoulou, Z; Papasteriades, A

    1995-09-01

    The present paper discusses "tongue rolling" observed in dairy cattle farms of a region in northern Greece associated with manganese deficiency. In these animals total body manganese status was evaluated by determining hair, as well as feed manganese content. Cows exhibiting tongue rolling had significantly lower hair manganese content, compared to non-tongue rolling control animals from other farms; in addition, feedstuff analysis demonstrated that manganese and inorganic phosphorus intake of affected cows was also significantly lower. PMID:8591770

  5. Chronic manganese poisoning: A neuropathological study with determination of manganese distribution in the brain

    Microsoft Academic Search

    M. Yamada; S. Ohno; I. Okayasu; R. Okeda; S. Hatakeyama; H. Watanabe; K. Ushio; H. Tsukagoshi

    1986-01-01

    An autopsy case of a 52-year-old man suffering from chronic manganese poisoning (CMP) is reported with determination of the manganese distribution in the brain. The patient had been working in a manganese ore crushing plant since 1965. In 1967 he began to complain of difficulties in walking and diminished libido. Later, he developed various neuro-psychiatric symptoms including euphoria, emotional incontinence,

  6. Recovery of cadmium and nickel from scrap batteries

    Microsoft Academic Search

    D. A. Wilson; B. J. Jr. Wiegard

    1971-01-01

    A cyclic leaching process was developed for selectively leaching and recovering cadmium from nickel--cadmium scrap battery waste. The six major steps in the process are the following: washing the plates to remove KOH electrolyte: roasting at 550 to 600C to oxidize metallic cadmium and decompose cadmium and nickel salts; leaching with an ammonium nitrate solution; precipitation of the leached cadmium

  7. Effect of fetal calf serum on the cadmium clastogenicity

    Microsoft Academic Search

    T. C. Wang; Mei-Lan Lee

    2001-01-01

    Inconsistent results among reports on cadmium genotoxicity revealed that certain confounding factors might significantly influence the outcomes of assessment. In Chinese hamster ovary (CHO-W8) cells, chromosome aberration induced by six different cadmium compounds was found positively associated with intracellular cadmium concentration. A parallel association was also observed among different CHO strains treated with same cadmium compound, the cadmium acetate. Both

  8. Analysis of manganese particulates from automotive decomposition of methylcyclopentadienyl manganese tricarbonyl

    NASA Astrophysics Data System (ADS)

    Colmenares, C.; Deutsch, Steven; Evans, Cheryl; Nelson, A. J.; Terminello, Louis J.; Reynolds, John G.; Roos, Joseph W.; Smith, Isaac L.

    1999-10-01

    Particulates have been collected and analyzed from automotive vehicles operating on fuel containing the organometallic antiknock additive methylcyclopentadienyl manganese tricarbonyl. Electron spectroscopy for chemical analysis and L-edge X-ray absorption spectroscopy were used to study and identify the manganese species present in these emitted particulates. Results show that respirable size particulates with a mass median aerodynamic diameter of 2.5 ?m or less (PM 2.5) in vehicle exhaust contain manganese primarily in the form of a manganese phosphate and/or sulfate.

  9. Uptake of heavy metals in batch systems by a recycled iron-bearing material

    Microsoft Academic Search

    Edward H. Smith

    1996-01-01

    An iron-bearing material deriving from surface finishing operations in the manufacturing of cast-iron components demonstrates potential for removal of heavy metals from aqueous waste streams. Batch isotherm and rate experiments were conducted for uptake of cadmium, zinc, and lead. In the pH range of 4–7, the iron sorbent had the highest capacity, on a mass-per-mass basis, for lead followed by

  10. Activation of methanogenesis by cadmium in the marine archaeon Methanosarcina acetivorans.

    PubMed

    Lira-Silva, Elizabeth; Santiago-Martínez, M Geovanni; Hernández-Juárez, Viridiana; García-Contreras, Rodolfo; Moreno-Sánchez, Rafael; Jasso-Chávez, Ricardo

    2012-01-01

    Methanosarcina acetivorans was cultured in the presence of CdCl(2) to determine the metal effect on cell growth and biogas production. With methanol as substrate, cell growth and methane synthesis were not altered by cadmium, whereas with acetate, cadmium slightly increased both, growth and methane rate synthesis. In cultures metabolically active, incubations for short-term (minutes) with 10 µM total cadmium increased the methanogenesis rate by 6 and 9 folds in methanol- and acetate-grown cells, respectively. Cobalt and zinc but not copper or iron also activated the methane production rate. Methanogenic carbonic anhydrase and acetate kinase were directly activated by cadmium. Indeed, cells cultured in 100 µM total cadmium removed 41-69% of the heavy metal from the culture and accumulated 231-539 nmol Cd/mg cell protein. This is the first report showing that (i) Cd(2+) has an activating effect on methanogenesis, a biotechnological relevant process in the bio-fuels field; and (ii) a methanogenic archaea is able to remove a heavy metal from aquatic environments. PMID:23152802

  11. Lead and cadmium content in human milk from the Northern Adriatic area of Croatia

    SciTech Connect

    Frkovic, A. [Rijeka Clinical Hospital, Rijeka (Croatia); Kras, M.; Alebic-Juretic, A. [Institute of Public Health, Rijeka (Croatia)

    1997-01-01

    Though occupational exposure to toxic metals (lead, cadmium) is well documented, harmful effects of environmental exposure to lower levels of these two metals is still under investigation. Most toxic metals are emitted by human activities and the atmosphere is the main transport route for these elements. According to some authors, 332 358 t of lead and 7570 t of cadmium were emitted in the atmosphere from anthropogenic sources in 1983. The principle source of lead is traffic, e.g. leaded petrol, still widely used in Croatia, as well as coal combustion, iron and steal production. Volcanic activity, zinc production and waste incineration are the main sources of cadmium. Recent study indicates that traffic could also be the main source of cadmium found along busy streets. Chronic lead exposure at low levels is associated with adverse health effects especially in fetus and young children. This study examines lead and cadmium levels in breast milk from nursing women living in the Northern Adriatic area of Croatia. 15 refs., 2 tabs.

  12. Iron chelators and iron toxicity

    Microsoft Academic Search

    Gary M. Brittenham

    2003-01-01

    Iron chelation may offer new approaches to the treatment and prevention of alcoholic liver disease. With chronic excess, either iron or alcohol alone may individually injure the liver and other organs. In combination, each exaggerates the adverse effects of the other. In alcoholic liver disease, both iron and alcohol contribute to the production of hepatic fibrosis through their effects on

  13. PHOSPHORUS ALLEVIATION OF CADMIUM PHYTOTOXICITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A hydroponic study was conducted under controlled environmental conditions to determine the effect of phosphate addition on cadmium (Cd) toxicity to soybean [Glycine max L. Cutiva perron] plants. Three weeks old soybean plants previously grown on perlite for two weeks and additional seven days on '...

  14. FACTORS AFFECTING BIOAVAILABILITY OF CADMIUM

    EPA Science Inventory

    A project was undertaken to examine reactions of metals with soils and soluble organics and to characterize plant uptake by cadmium (Cd). The project addressed three components of the sewage sludge-soil-plant system related to the bioavailability of Cd. These were the mechanisms ...

  15. Cadmium in jamaican bush teas.

    PubMed

    Hoo Fung, L A; Rattray, V R; Lalor, G C

    2014-01-01

    Samples of Jamaican plants used as bush teas were collected from households in high soil-cadmium (Cd) areas of central Jamaica and analysed by graphite furnace atomic absorption spectrophotometry for total cadmium and for cadmium extractable with a hot water brew as prepared for human consumption to determine their contribution to dietary cadmium exposure. The concentrations ranged from < 0.03 to 6.85 µg/g for total Cd, between 1 and 15% of which was extracted with a hot water brew. One cup (200 ml) of the teas examined was found to contain < 0.04-1.18 µg of Cd and would contribute 0.1-0.3 µg of Cd to a person's dietary intake. This is significantly below the provisional tolerable weekly intake (PTWI) of 7 µg Cd/kg body weight established by the World Health Organization (WHO). While this suggests that bush tea consumption does not contribute significantly to the PTWI, some of the teas examined exceed the WHO recommendation of less than 0.3 mg/kg Cd for medicinal plants. PMID:25303189

  16. Iron behavior in the ozonation and filtration of groundwater

    SciTech Connect

    Sallanko, J.; Lakso, E.; Ropelinen, J. [University of Oulu, Oulu (Finland)

    2006-08-15

    In Finnish groundwater, the main substances that require treatment are iron and manganese. In addition to this, groundwaters are soft and acidic. Iron removal is usually relatively effective by oxidizing dissolved iron into an insoluble form, either by aeration or chemical oxidation and removing the formed precipitate by sand filtration. Sometimes, if the untreated water contains high amounts of organic matter, problems may arise for iron removal. In Finland, it is quite common that groundwater contains high levels of both iron and natural organic matter, mainly as humic substances. The groundwater of the Kukkala intake plant in Liminka has been found to be problematic, due to its high level of natural organic matter. This research studied the removal of iron from this water by means of oxidation with ozone and filtration. While the oxidation of iron by ozone was rapid, the precipitate particles formed were small, and thus could not be removed by sand and anthracite filtration, and the iron residue in the treated water was more than 2 mg L{sup -1}. And while the filtration was able to remove iron well without the feed of ozone, the iron residue in the treated water was only 0.30 mg L{sup -1}. In this case, iron was led to the filter in a bivalent dissolved form. So, the result of iron removal was the best when the sand/anthracite filter functioned largely as an adsorption filter.

  17. Distribution of cadmium in the pearl oyster following exposure to cadmium in seawater

    SciTech Connect

    Francesconi, K.A. (Western Australian Marine Research Laboratories, North Beach (Australia))

    1989-08-01

    Laboratory studies on the uptake of cadmium from seawater have shown that bivalve molluscs readily accumulated cadmium from this medium and that the relative concentrations of cadmium between viscera and muscle were always the same as those found in natural populations. These results suggested that in the natural environment seawater was a major source of cadmium for bivalve molluscs. Results of a recent study have indicated that seawater is not always the major contributor of cadmium to bivalve molluscs. These authors reported high levels of cadmium in the pearl oyster Pinctada albina albina, collected from Shark Bay in Western Australia, and noted that there was no correlation between cadmium concentrations in the oysters and cadmium concentrations in the surrounding seawater. Australia is one of several countries which have a maximum permissible level of cadmium in molluscs. The possibility that the pearl oyster, and perhaps other molluscs as well, may accumulate cadmium preferentially in different tissues depending upon the source of cadmium has important implications in the area of contaminants in marine foodstuffs. The present study reports the uptake and distribution of cadmium within P. albina albina when subjected to cadmium in seawater alone.

  18. Chelation of cadmium.

    PubMed Central

    Andersen, O

    1984-01-01

    The toxicity of cadmium is determined by chelation reactions: in vivo, Cd2+ exists exclusively in coordination complexes with biological ligands, or with administered chelating agents. The Cd2+ ion has some soft character, but it is not a typical soft ion. It has a high degree of polarizability, and its complexes with soft ligands have predominantly covalent bond characteristics. Cd2+ forms the most stable complexes with soft donor atoms (S much greater than N greater than 0). The coordination stereochemistry of Cd2+ is unusually varied, including coordination numbers from 2 to 8. Even though the Cd2+ ion is a d10 ion, disturbed coordination geometries are often seen. Generally, the stability of complexes increases with the number of coordination groups contributed by the ligand; consequently, complexes of Cd2+ with polydentate ligands containing SH groups are very stable. Cd2+ in metallothionein (MT) is coordinated with 4 thiolate groups, and the log stability constant is estimated to 25.5. Complexes between Cd2+ and low molecular weight monodentate or bidentate ligands, e.g., free amino acids (LMW-Cd), seem to exist very briefly, and Cd2+ is rapidly bound to high molecular weight proteins, mainly serum albumin. These complexes (HMW-Cd) are rapidly scavenged from blood, mainly by the liver, and Cd2+ is redistributed to MT. After about 1 day the Cd-MT complex (MT-Cd) almost exclusively accounts for the total retained dose of Cd2+, independent of the route of exposure. MT-Cd is slowly transferred to and accumulated in kidney cortex. The acute toxicity and interorgan distribution of parenterally administered Cd2+ are strongly influenced by preceding MT induction, or decreased capacity for MT synthesis; however, the gastrointestinal (GI) uptake of Cd2+ seems unaffected by preceding MT induction resulting in considerable capacity for Cd2+ chelation in intestinal mucosa, and this finding indicates that endogenous MT is not involved in Cd2+ absorption. The toxicity of parenterally administered Cd2+ is strongly enhanced when administered as complexes with NTA or STPP , but it is much decreased when administered as a complex with EDTA. In chronic oral exposure the toxicity and GI uptake of Cd2+ is not changed when Cd2+ is administered as a complex with the detergent formula chelating agents NTA, EDTA and STPP . The uptake of Cd2+ from ligated intestine in vivo was not affected by administration of Cd2+ as complexes with CYS or GSH, but significantly reduced by complexation with EDTA or BAL. The acute toxicity of orally administered Cd2+ is reduced when Cd2+ is administered as a complex with EDTA.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6734560

  19. A manganese oxidation model for rivers

    SciTech Connect

    Hess, G.W. (Geological Survey, Doraville, GA (United States)); Kim, Byung R. (General Motors Research Lab., Warren, MI (United States)); Roberts, P.J.W. (Georgia Inst. of Tech, Atlanta (United States))

    1989-04-01

    The presence of manganese in natural waters (>0.05 mg/L) degrades water-supply quality. A model was devised to predict the variation of manganese concentrations in river water released from an impoundment with the distance downstream. The model is one-dimensional and was calibrated using dissolved oxygen, biochemical oxygen demand, pH, manganese, and hydraulic data collected in the Duck River, Tennessee. The results indicated that the model can predict manganese levels under various conditions. The model was then applied to the Chattahoochee River, Georgia. Discrepancies between observed and predicted may be due to inadequate pH data, precipitation of sediment particles, unsteady flow conditions in the Chattahoochee River, inaccurate rate expressions for the los pH conditions, or their combinations.

  20. HEALTH ASSESSMENT DOCUMENT FOR MANGANESE. FINAL REPORT

    EPA Science Inventory

    The document evaluates data on occurrence, sources, and transport of manganese in the environment and data on metabolism, pharmacokinetics, laboratory toxicological and epidemiologic studies to determine the nature and dose response relationship of potential health effects on hum...

  1. Methylcyclopentadienyl manganese tricarbonyl (MMT) in petrol: the toxicological issues.

    PubMed

    Abbott, P J

    1987-12-01

    Methylcyclopentadienyl manganese tricarbonyl (MMT), when used as an octane improver in petrol, leads to increased airborne levels of manganese in the form of Mn3O4. The potential health effects of increased airborne manganese are considered in this paper. Manganese, unlike lead which it can replace in petrol, is a normal and essential component of the human diet and the intake from airborne manganese is slight by comparison to the normal dietary intake. The major toxicological effects of manganese, observed after long occupational exposure, are on the lung (manganese pneumonia) and the central nervous system (manganism). The small increase in airborne manganese from the use of MMT in petrol is 3-4 orders of magnitude lower than the level required to produce toxic symptoms of manganese exposure, even in areas of high traffic density, and no health risk from the use of MMT is likely. PMID:3438743

  2. Mechanisms of cadmium induced genomic instability.

    PubMed

    Filipi?, Metka

    2012-05-01

    Cadmium is an ubiquitous environmental contaminant that represents hazard to humans and wildlife. It is found in the air, soil and water and, due to its extremely long half-life, accumulates in plants and animals. The main source of cadmium exposure for non-smoking human population is food. Cadmium is primarily toxic to the kidney, but has been also classified as carcinogenic to humans by several regulatory agencies. Current evidence suggests that exposure to cadmium induces genomic instability through complex and multifactorial mechanisms. Cadmium dose not induce direct DNA damage, however it induces increase in reactive oxygen species (ROS) formation, which in turn induce DNA damage and can also interfere with cell signalling. More important seems to be cadmium interaction with DNA repair mechanisms, cell cycle checkpoints and apoptosis as well as with epigenetic mechanisms of gene expression control. Cadmium mediated inhibition of DNA repair mechanisms and apoptosis leads to accumulation of cells with unrepaired DNA damage, which in turn increases the mutation rate and thus genomic instability. This increases the probability of developing not only cancer but also other diseases associated with genomic instability. In the in vitro experiments cadmium induced effects leading to genomic instability have been observed at low concentrations that were comparable to those observed in target organs and tissues of humans that were non-occupationally exposed to cadmium. Therefore, further studies aiming to clarify the relevance of these observations for human health risks due to cadmium exposure are needed. PMID:21945723

  3. Cadmium content of plants as affected by soil cadmium concentration

    SciTech Connect

    Lehoczky, E. [Pannon Univ. of Agricultural Sciences, Keszthely (Hungary); Szabados, I.; Marth, P. [Plant Health and Soil Conservation Station, Higany (Hungary)

    1996-12-31

    Pot experiments were conducted in greenhouse conditions to study the effects of increasing cadmium (Cd) levels on biomass production and Cd contents in corn, (Zea mays L.), garlic (Allium sativum L.), and spinach (Spinacia oleracea L.). Plants were grown in two soil types: Eutric cambisol soil and A gleyic luvisol soil. Spinach proved to be the most sensitive to Cd treatments as its biomass considerably decreased with the increasing Cd levels. Cadmium contents of the three crops increased with increasing levels of Cd applications. Statistical differences were observed in the Cd contents of crops depending on soil type. With the same Cd rates, Cd tissue concentration of test plants grown in the strongly acidic Gleyic luvisol soil were many times higher than that of plants grown in a neutral Eutric cambisol soil. 14 refs., 4 tabs.

  4. Methylcyclopentadienyl Manganese Tricarbonyl as an Antiknock: Composition and Fate of Manganese Exhaust Products

    Microsoft Academic Search

    G. L. Ter Haar; M. E. Grifffing; M. Brandt; D. G. Oberding; M. Kapron

    1975-01-01

    Methylcyclopentadienyl manganese tricarbonyl (MMT) has been marketed as a combustion improver for fuel oil and turbine fuel. Use concentrations for this purpose are about 0.025 g manganese\\/gal in fuel oil and 0.08 to 0.5 g\\/gal in turbine fuels. In addition, it has been used to a small extent in gasoline.

  5. Chronic manganese poisoning: a neuropathological study with determination of manganese distribution in the brain.

    PubMed

    Yamada, M; Ohno, S; Okayasu, I; Okeda, R; Hatakeyama, S; Watanabe, H; Ushio, K; Tsukagoshi, H

    1986-01-01

    An autopsy case of a 52-year-old man suffering from chronic manganese poisoning (CMP) is reported with determination of the manganese distribution in the brain. The patient had been working in a manganese ore crushing plant since 1965. In 1967 he began to complain of difficulties in walking and diminished libido. Later, he developed various neuropsychiatric symptoms including euphoria, emotional incontinence, masked face, monotonous speech, "cock-walk", increased muscle tone, weakness of upper and lower extremities, tremor of the eye lids, and exaggeration of knee jerks. The major neuropathological change was degeneration of the basal ganglia, in which the pallidum was severely affected. The pallidum disclosed a loss and degeneration of nerve cells, which was especially marked in the medial segment, a prominent decrease of myelinated fibers, and moderate astrocytic proliferation. The substantia nigra was intact. Distribution of manganese in the brain of the present case of CMP was determined using flameless atomic absorption spectrometry and compared with control cases and also a case of Parkinson's disease (PD). There was no significant difference between the control cases and the case of PD in average concentration of manganese and its distribution in the brain. The present case of CMP showed no elevation in average concentration of manganese in the brain. However, there were some changes in its distribution. Thus, the continuance of neurological disorders in CMP is not linked to an elevated manganese concentration itself in the brain. CMP appears to be different from PD in neuropathology and manganese behavior in brain. PMID:3766127

  6. Occupational exposure to cadmium and lung function.

    PubMed

    Cortona, G; Apostoli, P; Toffoletto, F; Baldasseroni, A; Ghezzi, I; Goggi, E; Fornari, S; Alessio, L

    1992-01-01

    A total of 69 male subjects occupationally exposed to cadmium fumes in a factory producing silver-cadmium-copper alloys for brazing, were subjected to lung function tests, including ventilation (FVC and FEV1), residual volume (RV) and alveolar-capillary diffusion capacity (TLCO and KCO). For each subject, the cumulative exposure to cadmium was calculated as the product of the number of years in the job and the average atmospheric concentration of cadmium (expressed in micrograms/m3) encountered each year. Cadmium-exposed subjects had moderately higher mean values of RV (+ 8%) as compared with the control group; the increase was greater (+ 10%) in the subgroup of workers with greater cumulative exposure to cadmium. No significant differences were observed in FVC, FEV1, TLCO and KCO. PMID:1303942

  7. Distillation of cadmium from uranium–plutonium–cadmium alloy

    Microsoft Academic Search

    Tetsuya Kato; Masatoshi Iizuka; Tadashi Inoue; Takashi Iwai; Yasuo Arai

    2005-01-01

    Uranium–plutonium alloy was prepared by distillation of cadmium from U–Pu–Cd ternary alloy. The initial ternary alloy contained 2.9wt% U and 8.7wt% Pu other than Cd, which were recovered by molten salt electrolysis with liquid Cd cathode. The distillation experiments were conducted in 10g scale of the initial alloy using a small-scale distillation furnace equipped with an evaporator and a condenser

  8. Metallothionein-like cadmium binding protein in rat testes administered with cadmium and selenium

    SciTech Connect

    Ohta, H.; Seki, Y.; Imamiya, S.

    1988-08-01

    It is well known that the testicular damage caused by acute cadmium toxicity are protected by simultaneous selenium administration with cadmium, and that the cadmium concentration in the testis increases remarkably as compared with that of only cadmium administration. The increased cadmium in the testis was found in the high molecular weight fraction containing selenium, and it has been thought that the shift of cadmium from the low molecular weight fraction to the high molecular weight fraction containing selenium is an important protection mechanism. However, the cadmium concentration in this high molecular weight fraction decreased with time, then re-shifted to the fraction of metallothionein, a low molecular weight protein having a protective effect against cadmium toxicity. While recently studying the cadmium binding protein, like metallothionein, in testes, it has been reported that the amino acid composition of cadmium binding protein in testis is not similar to that of the hepatic metallothionein. The present study was undertaken to clarify the properties of the increased cadmium binding protein in the testis protected by simultaneous selenium administration with cadmium.

  9. Tolerance to cadmium and cadmium-binding ligands in Great Salt Lake brine shrimp (Artemia salina)

    SciTech Connect

    Jayasekara, S.; Drown, D.B.; Sharma, R.P.

    1986-02-01

    Information on the accumulation of cadmium in cytosolic proteins of Great Lake brine shrimp (Artemia salina) was obtained from animals collected directly from the lake and also from animal hatched and maintained in three sublethal concentrations of cadmium (0.5, 2.0, 5.0 ppm) in saltwater aquaria. Brine shrimp growth under these conditions was monitored by measuring body lengths during a 7-day exposure period. Heat-stable, cadmium-binding ligands were isolated and identified by Sephadex G-75 chromatography and atomic absorption spectrophotometry. Cadmium was found to be equally distributed between high and low molecular weight proteins in animals collected from the lake and the 0.5 ppm cadmium group. There was also a slight growth stimulation noted in the 0.5-pm group. Higher cadmium incorporation was noted in low molecular weight fractions with increasing cadmium concentration in the exposure media. Low molecular weight fractions were also found to have high uv absorption characteristics at 250 nm and low absorption at 280 nm. Molecular weight of the cadmium-binding ligands was found to be 11,000 as estimated by the gel filtration method. De novo synthesis of this protein was increased as a function of cadmium concentration in the media. However, slow accumulation of cadmium in other protein fractions was also noticed in higher cadmium exposure groups, suggesting the existence of possible tolerance mechanisms in brine shrimp exposed to suspected acute cadmium concentrations.

  10. Laboratory Measurement Performance of Total Plant Cadmium as One Prerequisite to Manage for Soil Cadmium Minimization

    Microsoft Academic Search

    George E. Rayment

    2009-01-01

    Australia's National Cadmium Management Committee (NCMC) agreed to examine and publicize contemporary laboratory measurement performance for total plant cadmium (Cd) as part of its charter to implement the country's National Cadmium Minimization Strategy (NCMS). When the strategy was released in 2000, there was no published information for growers, merchants, and regulators identifying Australian laboratories competent to measure this regulated heavy

  11. EFFECTS OF CADMIUM-SPIKED SEDIMENT ON CADMIUM ACCUMULATION AND BIOTURBATION BY NYMPHS OF THE

    E-print Network

    Cope, W. Gregory

    EFFECTS OF CADMIUM-SPIKED SEDIMENT ON CADMIUM ACCUMULATION AND BIOTURBATION BY NYMPHS) Abstract. We assessed accumulation of cadmium (Cd) and bioturbation by nymphs of the burrowing mayfly-spiked sediment treatments plus an unspiked sediment control (1 µg Cd g-1 dry weight), and 10 nymphs in each

  12. Reduced cadmium body burden in cadmium-exposed calves fed supplemental zinc

    Microsoft Academic Search

    D. N. Lamphere; C. R. Dorn; C. S. Reddy; A. W. Meyer

    1984-01-01

    The objectives of this study were to evaluate the use of practical supplemental dietary zinc to modify the cadmium content in edible bovine tissues and to identify copper interactions with cadmium and zinc. The effect of supplemental zinc (200 or 600 ..mu..g\\/g) on the concentrations of cadmium, zinc, and copper in liver, kidney cortex, muscle, and blood of calves fed

  13. Frataxin depletion in yeast triggers up-regulation of iron transport systems before affecting iron-sulfur enzyme activities.

    PubMed

    Moreno-Cermeño, Armando; Obis, Elia; Bellí, Gemma; Cabiscol, Elisa; Ros, Joaquim; Tamarit, Jordi

    2010-12-31

    The primary function of frataxin, a mitochondrial protein involved in iron homeostasis, remains controversial. Using a yeast model of conditional expression of the frataxin homologue YFH1, we analyzed the primary effects of YFH1 depletion. The main conclusion unambiguously points to the up-regulation of iron transport systems as a primary effect of YFH1 down-regulation. We observed that inactivation of aconitase, an iron-sulfur enzyme, occurs long after the iron uptake system has been activated. Decreased aconitase activity should be considered part of a group of secondary events promoted by iron overloading, which includes decreased superoxide dismutase activity and increased protein carbonyl formation. Impaired manganese uptake, which contributes to superoxide dismutase deficiency, has also been observed in YFH1-deficient cells. This low manganese content can be attributed to the down-regulation of the metal ion transporter Smf2. Low Smf2 levels were not observed in AFT1/YFH1 double mutants, indicating that high iron levels could be responsible for the Smf2 decline. In summary, the results presented here indicate that decreased iron-sulfur enzyme activities in YFH1-deficient cells are the consequence of the oxidative stress conditions suffered by these cells. PMID:20956517

  14. Assessment of Occupational Exposure to Manganese and Other Metals in Welding Fumes by Portable X-ray Fluorescence Spectrometer

    Microsoft Academic Search

    Wisanti Laohaudomchok; Jennifer M. Cavallari; Shona C. Fang; Xihong Lin; Robert F. Herrick; David C. Christiani; Marc G. Weisskopf

    2010-01-01

    Elemental analysis of welding fume samples can be done using several laboratory-based techniques. However, portable measurement techniques could offer several advantages. In this study, we sought to determine whether the portable X-ray fluorescence spectrometer (XRF) is suitable for analysis of five metals (manganese, iron, zinc, copper, and chromium) on 37-mm polytetrafluoroethylene filters. Using this filter fitted on a cyclone in

  15. Biophysical and genetic analysis of iron partitioning and ferritin function in Drosophila melanogaster.

    PubMed

    Gutiérrez, Lucía; Zubow, Kristina; Nield, Jon; Gambis, Alexis; Mollereau, Bertrand; Lázaro, Francisco J; Missirlis, Fanis

    2013-08-01

    Metals have vital functions as prosthetic groups in enzymes, but in labile form they can propagate oxidative stress. The primary function of ferritin is to store bioavailable iron in the form of ferrihydrite. In animals, ferritin is also used to traffic and recycle iron, and to modulate intestinal iron absorption. However, the effect of ferritin accumulation on cellular iron bioavailability remains poorly understood. Moreover, putative in vivo interactions of ferritin with other metal ions have been proposed, but their physiological relevance remains unclear. Here, heterozygous mutant and overexpression ferritin strains of Drosophila melanogaster were subjected to dietary iron manipulations to study the dynamics of iron partition between ferritin and other proteins. Quantitative magnetic analysis of whole fly samples indicated that iron loading of the ferritin core varied in the different genotypes. Total paramagnetic iron content, a likely correlate of bioavailable iron, was reduced in flies overexpressing ferritin when compared with control white flies. Further, three-dimensional maps of the ferritin protein shell and iron core were obtained from single particle transmission electron microscopy imaging and confirmed the similarity between Drosophila and Trichoplusia ferritin structures. Purified Drosophila ferritin also contained small amounts of zinc and manganese. Flies that overexpressed ferritin accumulated in their bodies half the amount of manganese compared to their respective controls. Our results indicate that ferritin may be involved in the homeostasis of other divalent metals, besides iron, and that overexpression of ferritin, sometimes employed to rescue neurodegenerative models of disease, serves to limit divalent metal bio-availability in cells. PMID:23771129

  16. Cadmium content of umbilical cord blood

    SciTech Connect

    Rabinowitz, M.; Finch, H.

    1984-06-01

    Cadmium was measured in the umbilical cord blood at birth from 94 healthy babies. Samples were dried and ashed at low temperatures with an oxygen plasma prior to atomic absorption spectrometry. The concentration of cadmium ranged from 0.003 to 0.210 ..mu..g/dl, with a mean of 0.045 +/- 0.063 (SD). Blood lead, maternal smoking, and proximity of residence to automobile traffic were not statistically related to cadmium levels.

  17. Crystallographic and spectroscopic characterization and reactivities of a mononuclear non-haem iron(III)-superoxo complex.

    PubMed

    Hong, Seungwoo; Sutherlin, Kyle D; Park, Jiyoung; Kwon, Eunji; Siegler, Maxime A; Solomon, Edward I; Nam, Wonwoo

    2014-01-01

    Mononuclear non-haem iron(III)-superoxo species (Fe(III)-O2(-·)) have been implicated as key intermediates in the catalytic cycles of dioxygen activation by non-haem iron enzymes. Although non-haem iron(III)-superoxo species have been trapped and characterized spectroscopically in enzymatic and biomimetic reactions, no structural information has yet been obtained. Here we report the isolation, spectroscopic characterization and crystal structure of a mononuclear side-on (?(2)) iron(III)-superoxo complex with a tetraamido macrocyclic ligand. The non-haem iron(III)-superoxo species undergoes both electrophilic and nucleophilic oxidation reactions, as well as O2-transfer between metal complexes. In the O2-transfer reaction, the iron(III)-superoxo complex transfers the bound O2 unit to a manganese(III) analogue, resulting in the formation of a manganese(IV)-peroxo complex, which is characterized structurally and spectroscopically as a mononuclear side-on (?(2)) manganese(IV)-peroxo complex. The difference in the redox distribution between the metal ions and O2 in iron(III)-superoxo and manganese(IV)-peroxo complexes is rationalized using density functional theory calculations. PMID:25510711

  18. Process for removing cadmium from scrap metal

    DOEpatents

    Kronberg, James W. (Aiken, SC)

    1995-01-01

    A process for the recovery of a metal, in particular, cadmium contained in scrap, in a stable form. The process comprises the steps of mixing the cadmium-containing scrap with an ammonium carbonate solution, preferably at least a stoichiometric amount of ammonium carbonate, and/or free ammonia, and an oxidizing agent to form a first mixture so that the cadmium will react with the ammonium carbonate to form a water-soluble ammine complex; evaporating the first mixture so that ammine complex dissociates from the first mixture leaving carbonate ions to react with the cadmium and form a second mixture that includes cadmium carbonate; optionally adding water to the second mixture to form a third mixture; adjusting the pH of the third mixture to the acid range whereby the cadmium carbonate will dissolve; and adding at least a stoichiometric amount of sulfide, preferably in the form of hydrogen sulfide or an aqueous ammonium sulfide solution, to the third mixture to precipitate cadmium sulfide. This mixture of sulfide is then preferably digested by heating to facilitate precipitation of large particles of cadmium sulfide. The scrap may be divided by shredding or breaking up to expose additional surface area. Finally, the precipitated cadmium sulfide can be mixed with glass formers and vitrified for permanent disposal.

  19. Effects of dietary cadmium on mallard ducklings

    USGS Publications Warehouse

    Cain, B.W.; Sileo, L.; Franson, J.C.; Moore, J.

    1983-01-01

    Mallard (Anas platyrhynchos) ducklings were fed cadmium in the diet at 0, 5, 10, or 20 ppm from 1 day of age until 12 weeks of age. At 4-week intervals six males and six females from each dietary group were randomly selected, bled by jugular venipuncture, and necropsied. Significant decreases in packed cell volume (PCV) and hemoglobin (Hb) concentration and a significant increase in serum glutamic pyruvic transaminase (GPT) were found at 8 weeks of age in ducklings fed 20 ppm cadmium. Mild to severe kidney lesions were evident in ducklings fed 20 ppm cadmium for 12 weeks. No other blood chemistry measurement, hematological parameter, or tissue histopathological measurement indicated a reaction to cadmium ingestion. Body weight, liver weight, and the ratio of the femur weight to length were not affected by dietary cadmium. Femur cadmium concentration In all ducklings 12 weeks of age declined from the values detected at 4 and 8 weeks of age. Liver cadmium concentrations were significantly higher in relation to the increased dietary levels and in relation to the length of time the ducklings were fed the cadmium diets. At 12 weeks of age the cadmium concentration in liver tissue was twice that in the diet.

  20. Process for removing cadmium from scrap metal

    DOEpatents

    Kronberg, J.W.

    1994-01-01

    A process for the recovery of a metal, in particular, cadmium contained in scrap, in a stable form. The process comprises the steps of mixing the cadmium-containing scrap with an ammonium carbonate solution, preferably at least a stoichiometric amount of ammonium carbonate, and/or free ammonia, and an oxidizing agent to form a first mixture so that the cadmium will react with the ammonium carbonate to form a water-soluble ammine complex; evaporating the first mixture so that ammine complex dissociates from the first mixture leaving carbonate ions to react with the cadmium and form a second mixture that includes cadmium carbonate; optionally adding water to the second mixture to form a third mixture; adjusting the pH of the third mixture to the acid range whereby the cadmium carbonate will dissolve; and adding at least a stoichiometric amount of sulfide, preferably in the form of hydrogen sulfide or an aqueous ammonium sulfide solution, to the third mixture to precipitate cadmium sulfide. This mixture of sulfide is then preferably digested by heating to facilitate precipitation of large particles of cadmium sulfide. The scrap may be divided by shredding or breaking up to exposure additional surface area. Finally, the precipitated cadmium sulfide can be mixed with glass formers and vitrified for permanent disposal.

  1. Cadmium telluride photovoltaic radiation detector

    DOEpatents

    Agouridis, Dimitrios C. (Oak Ridge, TN); Fox, Richard J. (Oak Ridge, TN)

    1981-01-01

    A dosimetry-type radiation detector is provided which employs a polycrystalline, chlorine-compensated cadmium telluride wafer fabricated to operate as a photovoltaic current generator used as the basic detecting element. A photovoltaic junction is formed in the wafer by painting one face of the cadmium telluride wafer with an n-type semiconductive material. The opposite face of the wafer is painted with an electrically conductive material to serve as a current collector. The detector is mounted in a hermetically sealed vacuum containment. The detector is operated in a photovoltaic mode (zero bias) while DC coupled to a symmetrical differential current amplifier having a very low input impedance. The amplifier converts the current signal generated by radiation impinging upon the barrier surface face of the wafer to a voltage which is supplied to a voltmeter calibrated to read quantitatively the level of radiation incident upon the detecting wafer.

  2. Historical perspectives on cadmium toxicology

    SciTech Connect

    Nordberg, Gunnar F. [Environmental Medicine, Department of Public Health and Clinical Medicine, Umea University, SE-90187 Umea (Sweden)], E-mail: gunnar.nordberg@envmed.umu.se

    2009-08-01

    The first health effects of cadmium (Cd) were reported already in 1858. Respiratory and gastrointestinal symptoms occurred among persons using Cd-containing polishing agent. The first experimental toxicological studies are from 1919. Bone effects and proteinuria in humans were reported in the 1940's. After World War II, a bone disease with fractures and severe pain, the itai-itai disease, a form of Cd-induced renal osteomalacia, was identified in Japan. Subsequently, the toxicokinetics and toxicodynamics of Cd were described including its binding to the protein metallothionein. International warnings of health risks from Cd-pollution were issued in the 1970's. Reproductive and carcinogenic effects were studied at an early stage, but a quantitative assessment of these effects in humans is still subject to considerable uncertainty. The World Health Organization in its International Program on Chemical Safety, WHO/IPCS (1992) (Cadmium. Environmental Health Criteria Document 134, IPCS. WHO, Geneva, 1-280.) identified renal dysfunction as the critical effect and a crude quantitative evaluation was presented. In the 1990's and 2000 several epidemiological studies have reported adverse health effects, sometimes at low environmental exposures to Cd, in population groups in Japan, China, Europe and USA (reviewed in other contributions to the present volume). The early identification of an important role of metallothionein in cadmium toxicology formed the basis for recent studies using biomarkers of susceptibility to development of Cd-related renal dysfunction such as gene expression of metallothionein in peripheral lymphocytes and autoantibodies against metallothionein in blood plasma. Findings in these studies indicate that very low exposure levels to cadmium may give rise to renal dysfunction among sensitive subgroups of human populations such as persons with diabetes.

  3. Cadmium and postmenopausal bone loss

    SciTech Connect

    Bhattacharyya, M.H.; Whelton, B.D.; Stern, P.H.; Peterson, D.P.; Moretti, E.S.; Dare, H.A.

    1987-01-01

    Neither ovariectomy alone nor dietary cadmium exposure alone caused statistically significant decreases in the mean calcium contents and calcium/dry weight ratios of the femurs and lumbar vertebrae. Exposure to 50 ppM dietary Cd caused a significant increase in the loss of bone calcium after ovariectomy such that the calcium contents and calcium to dry weight ratios of both femurs and lumbar vertebrae were strikingly lower than those of all other groups.

  4. Crystal structure of the di-iron/radical protein of ribonucleotide reductase from Corynebacterium ammoniagenes.

    PubMed

    Högbom, Martin; Huque, Yasmin; Sjöberg, Britt-Marie; Nordlund, Pär

    2002-01-29

    Ribonucleotide reductase (RNR) is the enzyme performing de novo production of the four deoxyribonucleotides needed for DNA synthesis. All mammals as well as some prokaryotes express the class I enzyme which is an alpha(2)beta(2) protein. The smaller of the homodimers, denoted R2, contains a di-iron carboxylate site which, upon reaction with molecular oxygen, generates a stable tyrosyl radical needed for catalysis. The three-dimensional structure of the oxidized class Ib RNR R2 from Corynebacterium ammoniagenes has been determined at 1.85 A resolution and refined to an R-value of 15.8% (R(free) = 21.3%). In addition, structures of both the reduced iron-containing, and manganese-substituted protein have been solved. The C. ammoniagenes R2 has been proposed to be manganese-dependent. The present structure provides evidence that manganese is not oxidized by the protein, in agreement with recent biochemical data, and that no obvious structural abnormalities are seen in the oxidized and reduced iron-containing forms, giving further support that the protein is indeed an iron-dependent RNR R2. The di-manganese structure also provides an explanation for the magnetic properties of this site. The structure of the oxidized C. ammoniagenes R2 also reveals an additional water molecule bridging the radical and the iron site, which has not previously been seen in any other R2 structure and which might have important mechanistic implications. PMID:11802741

  5. Manganese Based Oxidative Technologies For Water/Wastewater Treatment

    E-print Network

    Desai, Ishan

    2013-08-27

    by facilitating redox reactions. The reactivity of manganese oxides with some emerging contaminants like 4-tert octylphenol (OP) in aqueous systems is yet to be explored. Additionally, manganese's use within treatment systems designed to remove trace organics...

  6. Cardiovascular Toxicities Upon Manganese Exposure

    PubMed Central

    Jiang, Yueming; Zheng, Wei

    2014-01-01

    Manganese (Mn)-induced Parkinsonism has been well documented; however, little attention has been devoted to Mn-induced cardiovascular dysfunction. This review summarizes literature data from both animal and human studies on Mn’s effect on cardiovascular function. Clinical and epidemiological evidence suggests that the incidence of abnormal electrocardiogram (ECG) is significantly higher in Mn-exposed workers than that in the control subjects. The main types of abnormal ECG include sinus tachycardia, sinus bradycardia, sinus arrhythmia, sinister megacardia, and ST-T changes. The accelerated heartbeat and shortened P-R interval appear to be more prominent in female exposed workers than in their male counterparts. Mn-exposed workers display a mean diastolic blood pressure that is significantly lower than that of the control subjects, especially in the young and female exposed workers. Animal studies indicate that Mn is capable of quickly accumulating in heart tissue, resulting in acute or sub-acute cardiovascular disorders, such as acute cardiodepression and hypotension. These toxic outcomes appear to be associated with Mn-induced mitochondrial damage and interaction with the calcium channel in the cardiovascular system. PMID:16382172

  7. Nephropathy in cadmium workers: assessment of risk from airborne occupational exposure to cadmium.

    PubMed Central

    Thun, M J; Osorio, A M; Schober, S; Hannon, W H; Lewis, B; Halperin, W

    1989-01-01

    To assess the quantitative relation between exposure to airborne cadmium and various markers of renal tubular and glomerular function, 45 male workers employed at a plant that recovers cadmium from industrial waste and 32 male hospital workers of similar age and geographical location were examined. Cumulative external exposure to airborne cadmium (dose) was estimated from historical air sampling data, adjusted for respirator use. Increasing cadmium dose was associated with multiple renal tubular functional abnormalities, including reduced reabsorption of beta-2-microglobulin (beta-2), retinol binding protein (RBP), calcium, and phosphate. Serum creatinine concentration also increased with cadmium dose, suggesting impaired glomerular function. Mean systolic and diastolic blood pressures were higher in the cadmium workers than in the unexposed (134 v 120 mm Hg and 80 v 73 mm Hg respectively), but only systolic blood pressure was significantly associated with cadmium dose in multivariate analyses. Cadmium dose remained the most important predictor of serum creatinine concentration after controlling for age, blood pressure, body size, and other extraneous factors. Logistic regression to model the probability (prevalence) of various renal abnormalities with increasing dose of cadmium was used. The probability of multiple tubular abnormalities and raised serum creatinine concentration increased sharply at cumulative cadmium exposures exceeding 300 mg/m3 days, corresponding to working for 4.3 years at the current permissible United States exposure limit for cadmium dust. PMID:2818957

  8. Pulmonary clearance of manganese phosphate, manganese sulfate, and manganese tetraoxide by CD rats following intratracheal instillation.

    PubMed

    Vitarella, D; Moss, O; Dorman, D C

    2000-10-01

    Manganese (Mn) is ubiquitous in ambient air due to both industrial and crustal sources. It is also a component of the octane-enhancing fuel additive methylcyclopentadienyl manganese tricarbonyl (MMT). The combustion of MMT by the automobile engine results in the formation of Mn particulates including phosphate, sulfate, and oxide forms. The objectives of this study were to determine the contribution of particle dissolution on pulmonary clearance rates of Mn sulfate (MnSO(4)), Mn phosphate, and Mn tetraoxide (Mn(3)O(4)) in CD rats following an intratracheal instillation exposure. In addition, brain (striatal) Mn concentrations were evaluated following exposure. Adult CD rats were intratracheally instilled with 0, 0.04, 0.08, or 0.16 microg Mn/g of either MnSO(4), Mn phosphate, or Mn(3)O(4). Rats were euthanized at 0, 1, 3, or 14 days after instillation. Lung and striatal Mn concentrations were measured by neutron activation analysis. Pulmonary clearance following single intratracheal instillation of MnSO(4), Mn phosphate, or Mn(3)O(4) was similar for each of the three compounds at each of the three doses used. All pulmonary clearance half-times were less than 0.5 day. At the concentrations used, striatal Mn levels were unaffected, and lung pathology was unremarkable. The dissolution rate constant of the Mn particles was determined in vitro using lung simulant fluids. The solubility of the Mn compounds was in general 20 to 40 times greater in Hatch artificial lung lining fluid than in Gamble lung simulant fluid. The dissolution rate constant of the water-soluble MnSO(4) particles in Hatch artificial lung fluid containing protein was 7.5 x 10(-4) g (Mn)/cm(2)/day, which was 54 times that of relatively water-insoluble Mn phosphate and 3600 times that of Mn(3)O(4). The dissolution rate constants for these compounds were sevenfold slower in Gamble lung fluid simulant. For both solutions, the time for half the material to go into solution differed only by factors of 1/83 to 1/17 to 1 for MnSO(4), Mn phosphate, and Mn(3)O(4), respectively, consistent with measured differences in size distribution, specific surface, and dissolution rate constant. These data suggest that dissolution mechanisms only played a role in the pulmonary clearance of MnSO(4), while nonabsorptive (e.g., mechanical transport) mechanisms predominate for the less soluble phosphate and oxide forms of Mn. PMID:10989370

  9. Environmental effects and exposures to manganese from use of methylcyclopentadienyl manganese tricarbonyl (MMT) in gasoline.

    PubMed

    Lynam, D R; Roos, J W; Pfeifer, G D; Fort, B F; Pullin, T G

    1999-01-01

    Methylcyclopentadienyl Manganese Tricarbonyl (MMT) has been used since the 1970s in the U.S. as a gasoline octane enhancer Extensive testing of the effects of MMT on regulated gaseous emissions carried out on a wide variety of automobiles showed that use of MMT resulted in significantly lower NOx emissions Tests showed that less than 15% of the manganese from MMT combustion was emitted from the tailpipe, mostly in the PM2.5 fraction as manganese phosphate, with some manganese sulfate and a very small amount of manganese oxide. MMT has been used in Canada in virtually all unleaded gasoline for about 20 years. A probability-based study involving over 900 personal exposure samples in Toronto confirmed exposures to airborne PM2.5 Mn in the general population are quite low (.008 microgram/m3-median). Ambient levels of airborne manganese in Toronto are about the same as those in areas where MMT is not used. Exposures to manganese among the general population in Toronto are well within safe limits determined by the U.S. EPA and other standard setting bodies around the world. PMID:10385878

  10. Manganese oxide reduction as a form of anaerobic respiration

    Microsoft Academic Search

    Henry L. Ehrlich

    1987-01-01

    Some instances of bacterial manganese oxide reduction observed in nature and under laboratory conditions are a form of respiration. Anaerobiosis is not a necessary condition for its occurrence, although anaerobic reduction of manganese oxide which is inhibited by air has been reported. It is the kind of manganese reducing microorganism involved which determines whether anaerobic conditions are required. In at

  11. Essentiality, Toxicity, and Uncertainty in the Risk Assessment of Manganese

    Microsoft Academic Search

    William K. Boyes

    2010-01-01

    Risk assessments of manganese by inhalation or oral routes of exposure typically acknowledge the duality of manganese as an essential element at low doses and a toxic metal at high doses. Previously, however, risk assessors were unable to describe manganese pharmacokinetics quantitatively across dose levels and routes of exposure, to account for mass balance, and to incorporate this information into

  12. 40 CFR 721.10201 - Cobalt lithium manganese nickel oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Cobalt lithium manganese nickel oxide. 721.10201 Section 721...721.10201 Cobalt lithium manganese nickel oxide. (a) Chemical substance and...identified as cobalt lithium manganese nickel oxide (PMN P-04-269; CAS...

  13. 40 CFR 721.10201 - Cobalt lithium manganese nickel oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Cobalt lithium manganese nickel oxide. 721.10201 Section 721...721.10201 Cobalt lithium manganese nickel oxide. (a) Chemical substance and...identified as cobalt lithium manganese nickel oxide (PMN P-04-269; CAS...

  14. 40 CFR 721.10201 - Cobalt lithium manganese nickel oxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Cobalt lithium manganese nickel oxide. 721.10201 Section 721...721.10201 Cobalt lithium manganese nickel oxide. (a) Chemical substance and...identified as cobalt lithium manganese nickel oxide (PMN P-04-269; CAS...

  15. Biological manganese removal from potable water using trickling filters

    Microsoft Academic Search

    A. G. Tekerlekopoulou; I. A. Vasiliadou; D. V. Vayenas

    2008-01-01

    Two pilot-scale trickling filters were constructed and tested for manganese removal from potable water, using different fractions of silicic gravel as support media (mono- and multilayer filter). Manganese oxidation in drinking water was found to be cause by both biological oxidation and heterogeneous catalytic paths. Mixed culture populations were used to inoculate the trickling filters and the feed manganese concentrations

  16. EFFECT OF NORMAL AND HIGH MANGANESE DIETS ON THE ROLE OF BILE IN MANGANESE METABOLISM OF CALVES

    Microsoft Academic Search

    E. Abrams; J. W. Lassiter; W. J. Miller; M. W. Neathery; R. P. Gentry; D. M. Blackmon

    2010-01-01

    SUMMARY The role of bile in manganese metabolism and homeostasis was studied in Holstein bull calves fed diets containing 32 ppm manganese (normal) (control) or 1,000 ppm supplemental manganese (high-manganese) for 2 weeks before and 1 week after intravenous (IV) and duodenal S4Mn dosing. After dosing, all the bile was collected at 15 and 60 minutes, hourly to 12 hr

  17. Mapping of cellular iron using hyperspectral fluorescence imaging in a cellular model of Parkinson's disease

    NASA Astrophysics Data System (ADS)

    Oh, Eung Seok; Heo, Chaejeong; Kim, Ji Seon; Lee, Young Hee; Kim, Jong Min

    2013-05-01

    Parkinson's disease (PD) is characterized by progressive dopaminergic cell loss in the substantianigra (SN) and elevated iron levels demonstrated by autopsy and with 7-Tesla magnetic resonance imaging. Direct visualization of iron with live imaging techniques has not yet been successful. The aim of this study is to visualize and quantify the distribution of cellular iron using an intrinsic iron hyperspectral fluorescence signal. The 1-methyl-4-phenylpyridinium (MPP+)-induced cellular model of PD was established in SHSY5Y cells. The cells were exposed to iron by treatment with ferric ammonium citrate (FAC, 100 ?M) for up to 6 hours. The hyperspectral fluorescence imaging signal of iron was examined usinga high- resolution dark-field optical microscope system with signal absorption for the visible/ near infrared (VNIR) spectral range. The 6-hour group showed heavy cellular iron deposition compared with the small amount of iron accumulation in the 1-hour group. The cellular iron was dispersed in a small, particulate form, whereas extracellular iron was detected in an aggregated form. In addition, iron particles were found to be concentrated on the cell membrane/edge of shrunken cells. The cellular iron accumulation readily occurred in MPP+-induced cells, which is consistent with previous studies demonstrating elevated iron levels in the SN in PD. This direct iron imaging methodology could be applied to analyze the physiological role of iron in PD, and its application might be expanded to various neurological disorders involving other metals, such as copper, manganese or zinc.

  18. Effects of Iron-Rich Intermetallics on Tensile Deformation of Al-Cu 206 Cast Alloys

    NASA Astrophysics Data System (ADS)

    Liu, K.; Cao, X.; Chen, X.-G.

    2015-01-01

    An investigation has been carried out of the influence of iron on the tensile properties and fracture behavior of a series of Al-Cu 206 cast alloys. Iron contents are explored from 0.15 to 0.5 wt pct, and at two levels of silicon and manganese. The types, morphologies and quantities of the various iron-rich intermetallics are characterized metallographically, and their effects on the tensile properties and the nucleation and growth of cracks during tensile deformation are studied. In addition, oxide films are shown to play an important role in both the nucleation of the iron-rich intermetallics and the formation of tensile cracks.

  19. Comparative toxicokinetics of manganese chloride and methylcyclopentadienyl manganese tricarbonyl (MMT) in Sprague-Dawley rats.

    PubMed

    Zheng, W; Kim, H; Zhao, Q

    2000-04-01

    The toxicokinetics of manganese (Mn) was investigated in male and female rats either following a single intravenous (iv) or oral dose of MnCl2 (6.0 mg Mn/kg), or following a single oral dose of methylcyclopentadienyl manganese tricarbonyl (MMT) (20 mg MMT/kg or 5.6 mg Mn/kg). The plasma concentrations of manganese were quantified by atomic absorption spectrophotometry (AAS). Upon iv administration of MnCl2, manganese rapidly disappeared from blood with a terminal elimination t1/2 of 1.83 h and CL8 of 0.43 L/h/kg. The plasma concentration-time profiles of manganese could be described by C = 41.9e(-424t) + 2.1e(-0.44t). Following oral administration of MnCl2, manganese rapidly entered the systemic circulation (Tmax = 0.25 h). The absolute oral bioavailability was about 13%. Oral dose of MMT resulted in a delayed Tmax(7.6 h), elevated Cmax (0.93 microg/ml), and prolonged terminal t1/2 (55.1 h). The rats receiving MMT had an apparent clearance (CL/F = 0.09 L/h x kg) about 37-fold less than did those who were dosed with MnCl2. Accordingly, the area under the plasma concentration-time curves (AUC) of manganese in MMT-treated rats was about 37-fold greater than that in MnCl2-treated rats. A gender-dependent difference in toxicokinetic profiles of plasma manganese was also observed. Female rats displayed a greater AUC than that of male rats. Although the apparent volume of distribution of manganese was similar in both sexes, the apparent clearance in males was about twice that observed in females. The results indicated that after oral administration, the MMT-derived manganese displayed higher and more prolonged plasma concentration-time profiles than MnCl2-derived manganese. Thus, MMT-derived manganese appeared likely to accumulate in the body following repeated exposure. PMID:10774811

  20. Original article Calcium-cadmium interaction

    E-print Network

    Paris-Sud XI, Université de

    Original article Calcium-cadmium interaction on L-threonine intestinal transport JE Mesonero MC to membrane proteins which pertain to active transport systems or are func- tionally related to them. Calcium be modified by calcium. In media with Ca2+, cadmium signifi- cantly reduces the L-threonine absorption. In Ca2

  1. Cadmium and chromium recovery from electroplating rinsewaters

    Microsoft Academic Search

    A. R. Gavaskar; R. F. Olfenbuttel; J. A. Jones; L. Brown

    1994-01-01

    This evaluation addresses the product quality, pollution prevention, and economic issues involved in the use of ion exchange to recover cadmium and chromium from electroplating rinse waters. Test results showed that the water returned to the rinse after ion exchange was of acceptable quality. On the cadmium line, the ion exchange resin was regenerated with sodium hydroxide solution and the

  2. Cadmium Biosorption Rate in Protonated Sargassum Biomass

    E-print Network

    Volesky, Bohumil

    Cadmium Biosorption Rate in Protonated Sargassum Biomass J I N B A I Y A N G A N D B O H U M I L V Sargassum fluitans biomass was accompanied by the release of hydrogen protons from the biomass. The uptake the overall biosorption rate of cadmium ions in flat seaweed biomass particles. The overall biosorption

  3. Association of urinary cadmium and myocardial infarction

    SciTech Connect

    Everett, Charles J. [Department of Family Medicine, Medical University of South Carolina, 295 Calhoun Street, P.O. Box 250192, Charleston, SC 29425 (United States)], E-mail: everettc@musc.edu; Frithsen, Ivar L. [Department of Family Medicine, Medical University of South Carolina, 295 Calhoun Street, P.O. Box 250192, Charleston, SC 29425 (United States)], E-mail: frithse@musc.edu

    2008-02-15

    We conducted a cross-sectional analysis of individuals 45-79 years old in the National Health and Nutrition Examination Survey III (1988-1994) (NHANES III). Myocardial infarction was determined by electrocardiogram (ECG). Our sample included 4912 participants, which when weighted represented 52,234,055 Americans. We performed adjusted logistic regressions with the Framingham risk score, pack-years of smoking, race-ethnicity, and family history of heart attack, and diabetes as covariates. Urinary cadmium {>=}0.88 {mu}g/g creatinine had an odds ratio of 1.86 (95% CI 1.26-2.75) compared to urinary cadmium <0.43 {mu}g/g creatinine. This result supports the hypothesis that cadmium is associated with coronary heart disease. When logistic regressions were done by gender, women, but not men, showed a significant association of urinary cadmium with myocardial infarction. Women with urinary cadmium {>=}0.88 {mu}g/g creatinine had an odds ratio of 1.80 (95% CI 1.06-3.04) compared to urinary cadmium <0.43 {mu}g/g creatinine. When the analysis was restricted to never smokers (N=2187) urinary cadmium {>=}0.88 {mu}g/g creatinine had an odds ratio of 1.85 (95% CI 1.10-3.14) compared to urinary cadmium <0.43 {mu}g/g creatinine.

  4. Plastic bonded electrodes in nickel cadmium batteries

    Microsoft Academic Search

    A. O. Nilsson

    1989-01-01

    The characteristics of nickel-cadmium batteries with plastic bonded electrodes are presented. The active materials, nickel hydroxide and cadmium oxide, are mixed with plastic powder and a solvent to form a thick paste. The paste is extruded or rolled into a strip, which is then laminated to current collectors of pure nickel or nickel-plated steel. The manufacturing process allows more efficient

  5. Femtosecond optical characterization and applications in cadmium(manganese) telluride diluted magnetic semiconductors

    Microsoft Academic Search

    Daozhi Wang

    2008-01-01

    This thesis is devoted to the optical characterization of Cd(Mn)Te single crystals. I present the studies of free-carrier dynamics and generation and detection of coherent acoustic phonons (CAPS) using time-resolved femtosecond pump-probe spectroscopy. The giant Faraday effect and ultrafast responsivity of Cd(Mn)Te to sub-picosecond electromagnetic transients are also demonstrated and discussed in detail. The first, few-picosecond-long electronic process after the

  6. Manganese Dioxide nanosheet suspension: A novel absorbent for Cadmium(II) contamination in waterbody.

    PubMed

    Peng, Liang; Zeng, Qingru; Tie, Boqing; Lei, Ming; Yang, Jiao; Luo, Si; Song, Zhengguo

    2015-10-15

    A MnO2 nanosheet (MnO2-NS) suspension was prepared from tetramethylammonium hydroxide (TMA?OH), H2O2, and MnCl2?4H2O, and its efficiency for Cd(II) removal from aqueous solutions was investigated. The maximum adsorption capacity of the MnO2-NS for Cd(II) was evaluated to be about 348mg/g, which is thus far the highest value reported for MnO2 at pH 6.0. This high adsorption capacity is attributed to efficient ion exchange. X-ray photoelectron spectroscopy (XPS) revealed that Cd(II) was adsorbed on MnO2 as CdO and Cd(OH)2. After Cd(II) adsorption, the suspended MnO2-NS aggregated and precipitated within 5.0min from solution. Therefore, dispersive MnO2-NS can be used to remove Cd(II) from wastewater rapidly and with high efficiency. PMID:26111516

  7. Cloning, expression, and characterization of cadmium and manganese uptake genes from Lactobacillus plantarum

    SciTech Connect

    Hao, Z.; Chen, S.; Wilson, D.B.

    1999-11-01

    An Mn{sup 2+} and Cd{sup 2+} uptake gene, mntA, was cloned from Lactobacillus plantarum ATCC 14917 into Escherichia coli. Its expression conferred on E. coli cells increased Cd{sup 2+} sensitivity as well as energy-dependent Cd{sup 2+} uptake activity. Both transcription and translation of mntA were induced by Mn{sup 2+} starvation in L. plantarum, as indicated by reverse transcriptase PCR and immunoblotting. Two Cd{sup 2+} uptake systems have been identified in L. plantarum: one is a high-affinity Mn{sup 2+} and Cd{sup 2+} uptake system that is expressed in Mn{sup 2+}-starved cells, and the other is a nonsaturable Cd{sup 2+} uptake system that is expressed in Cd{sup 2+}-sufficient cells. MntA was not detected in an Mn{sup 2+}-dependent mutant of L. plantarum which had lost high-affinity Mn{sup 2+} and Cd{sup 2+} uptake activity. The results suggest that mntA is the gene encoding the high-affinity Mn{sup 2+} and Cd{sup 2+} transporter. On the basis of its predicted amino acid sequence, MntA belongs to the family of P-type cation-translocating ATPases. The topology and potential Mn{sup 2+}- and Cd{sup 2+}-binding sites of MntA are discussed. A second clone containing a low-affinity Cd{sup 2+} transport system was also isolated.

  8. The kinetics of fluoride sorption by zeolite: Effects of cadmium, barium and manganese

    NASA Astrophysics Data System (ADS)

    Cai, Qianqian; Turner, Brett D.; Sheng, Daichao; Sloan, Scott

    2015-06-01

    Industrial wastewaters often consist of a complex chemical cocktail with treatment of target contaminants complicated by adverse chemical reactions. The impact of metal ions (Cd2 +, Ba2 + and Mn2 +) on the kinetics of fluoride removal from solution by natural zeolite was investigated. In order to better understand the kinetics, the pseudo-second order (PSO), Hill (Hill 4 and Hill 5) and intra-particle diffusion (IPD) models were applied. Model fitting was compared using the Akaike Information Criterion (AIC) and the Schwarz Bayesian Information Criterion (BIC). The Hill models (Hill 4 and Hill 5) were found to be superior in describing the fluoride removal processes due to the sigmoidal nature of the kinetics. Results indicate that the presence of Mn (100 mg L- 1) and Cd (100 mg L- 1) respectively increases the rate of fluoride sorption by a factor of ~ 28.3 and ~ 10.9, the maximum sorption capacity is increased by ~ 2.2 and ~ 1.7. The presence of Ba (100 mg L- 1) initially inhibited fluoride removal and very poor fits were obtained for all models. Fitting was best described with a biphasic sigmoidal model with the degree of inhibition decreasing with increasing temperature suggesting that at least two processes are involved with fluoride sorption onto natural zeolite in the presence of Ba.

  9. Femtosecond optical characterization and applications in cadmium(manganese) telluride diluted magnetic semiconductors

    NASA Astrophysics Data System (ADS)

    Wang, Daozhi

    This thesis is devoted to the optical characterization of Cd(Mn)Te single crystals. I present the studies of free-carrier dynamics and generation and detection of coherent acoustic phonons (CAPS) using time-resolved femtosecond pump-probe spectroscopy. The giant Faraday effect and ultrafast responsivity of Cd(Mn)Te to sub-picosecond electromagnetic transients are also demonstrated and discussed in detail. The first, few-picosecond-long electronic process after the initial optical excitation exhibits very distinct characteristic dependence on the excitation condition, and in case of Cd(Mn)Te, it has been attributed to the collective effects of band filling, band renormalization, and two-photon absorption. A closed-form, analytic expression for the differential reflectivity induced by the CAPs is derived based on the propagating-strain-pulse model and it accounts very well for our experimental observations. The accurate values of the Mn concentration and longitudinal sound velocity nu s in Cd(Mn)Te were obtained by fitting the data of the refractive index dependence on the probe wavelength to the Schubert model. In Cd 0.91Mn0.09Te, nus was found to be 3.6x103 m/s. Our comparison studies from the one-color and two-color experiments reveal that the intrinsic phonon lifetime in Cd(Mn)Te was at least on the order of nanoseconds, and the observed exponential damping of the CAP oscillations was due to the finite absorption depth of the probe light. Optically-induced electronic stress has been demonstrated to be the main generation mechanism of CAPs. We also present the giant Faraday effect in the Cd(Mn)Te and the spectra of the Verdet constant, which is mainly due to the exchange interaction between the Mn ions and band electrons. The spectral characteristics of the Verdet constant in Cd(Mn)Te exhibit very unique features compared to that in pure semiconductors. In our time-resolved sampling experiments at the room temperature, the response of the Cd(Mn)Te, particularly with low Mn concentrations, to the sub-picosecond electromagnetic pulses has been demonstrated for the first time and studied in detail. The physical origin of the ultrafast responsivity is shown to be the electro-optic (Pockels) effect, simultaneously excluding the magneto-optical (Faraday) effect due to the Mn-ion spin dynamics. The discrepancy between the absence of the low-frequency Pockels effect and the ultrafast sampling results, suggests that in Cd(Mn)Te crystals at low frequencies, the electric field component of the external electromagnetic transients is screened by the free carriers (holes). At very high (THz) frequencies, tested by our sampling experiment, Mn spins are too slow to respond and we observe the very large Pockels effect in Cd(Mn)Te crystals.

  10. The kinetics of fluoride sorption by zeolite: Effects of cadmium, barium and manganese.

    PubMed

    Cai, Qianqian; Turner, Brett D; Sheng, Daichao; Sloan, Scott

    2015-01-01

    Industrial wastewaters often consist of a complex chemical cocktail with treatment of target contaminants complicated by adverse chemical reactions. The impact of metal ions (Cd(2+), Ba(2+) and Mn(2+)) on the kinetics of fluoride removal from solution by natural zeolite was investigated. In order to better understand the kinetics, the pseudo-second order (PSO), Hill (Hill 4 and Hill 5) and intra-particle diffusion (IPD) models were applied. Model fitting was compared using the Akaike Information Criterion (AIC) and the Schwarz Bayesian Information Criterion (BIC). The Hill models (Hill 4 and Hill 5) were found to be superior in describing the fluoride removal processes due to the sigmoidal nature of the kinetics. Results indicate that the presence of Mn (100mgL(-1)) and Cd (100mgL(-1)) respectively increases the rate of fluoride sorption by a factor of ~28.3 and ~10.9, the maximum sorption capacity is increased by ~2.2 and ~1.7. The presence of Ba (100mgL(-1)) initially inhibited fluoride removal and very poor fits were obtained for all models. Fitting was best described with a biphasic sigmoidal model with the degree of inhibition decreasing with increasing temperature suggesting that at least two processes are involved with fluoride sorption onto natural zeolite in the presence of Ba. PMID:25909159

  11. Mouse genetic background impacts both on iron and non-iron metals parameters and on their relationships.

    PubMed

    Cavey, Thibault; Ropert, Martine; de Tayrac, Marie; Bardou-Jacquet, Edouard; Island, Marie-Laure; Leroyer, Patricia; Bendavid, Claude; Brissot, Pierre; Loréal, Olivier

    2015-08-01

    Iron is reported to interact with other metals. In addition, it has been shown that genetic background may impact iron metabolism. Our objective was to characterize, in mice of three genetic backgrounds, the links between iron and several non-iron metals. Thirty normal mice (C57BL/6, Balb/c and DBA/2; n = 10 for each group), fed with the same diet, were studied. Quantification of iron, zinc, cobalt, copper, manganese, magnesium and rubidium was performed by ICP/MS in plasma, erythrocytes, liver and spleen. Transferrin saturation was determined. Hepatic hepcidin1 mRNA level was evaluated by quantitative RT-PCR. As previously reported, iron parameters were modulated by genetic background with significantly higher values for plasma iron parameters and liver iron concentration in DBA/2 and Balb/c strains. Hepatic hepcidin1 mRNA level was lower in DBA/2 mice. No iron parameter was correlated with hepcidin1 mRNA levels. Principal component analysis of the data obtained for non-iron metals indicated that metals parameters stratified the mice according to their genetic background. Plasma and tissue metals parameters that are dependent or independent of genetic background were identified. Moreover, relationships were found between plasma and tissue content of iron and some other metals parameters. Our data: (i) confirms the impact of the genetic background on iron parameters, (ii) shows that genetic background may also play a role in the metabolism of non-iron metals, (iii) identifies links between iron and other metals parameters which may have implications in the understanding and, potentially, the modulation of iron metabolism. PMID:26041486

  12. Manganese Distribution in the Brain and Neurobehavioral Changes Following Inhalation Exposure of Rats to Three Chemical Forms of Manganese

    Microsoft Academic Search

    Louise Normandin; Linda Ann Beaupré; Fariba Salehi; Annie St.-Pierre; Greg Kennedy; Donna Mergler; Roger F Butterworth; Suzanne Philippe; Joseph Zayed

    2004-01-01

    The central nervous system is an important target for manganese (Mn) intoxication in humans; it may cause neurological symptoms similar to Parkinson’s disease. Manganese compounds emitted from the tailpipe of vehicles using methylcyclopentadienyl manganese tricarbonyl (MMT) are primarily Mn phosphate, Mn sulfate, and Mn phosphate\\/sulfate mixture. The purpose of this study is to compare the patterns of Mn distribution in

  13. Engineering-scale distillation of cadmium for actinide recovery

    Microsoft Academic Search

    B. R. Westphal; J. C. Price; D. Vaden; R. W. Benedict

    2007-01-01

    During the recovery of actinide products from spent nuclear fuel, cadmium is separated from the actinide products by a distillation process. Distillation occurs in an induction-heated furnace called a cathode processor capable of processing kilogram quantities of cadmium. Operating parameters have been established for sufficient recovery of the cadmium based on mass balance and product purity. A cadmium distillation rate

  14. Sorption of cobalt and cadmium by Mexican erionite

    Microsoft Academic Search

    I. García-Sosa; M. Solache Ríos

    1997-01-01

    The sorption behaviour of cobalt and cadmium by Mexican erionite was studied at different pH values and the ion exchange isothems were determined. Sorption experiments were performed with cobalt and cadmium solutions. The cobalt, cadmium and sodium content in the aluminosilicate samples were determined by neutron activation analysis. It was found that the sorption for cadmium was higher than for

  15. Influence of protein deficiency on cadmium toxicity in rats

    Microsoft Academic Search

    P. C. Tewari; V. K. Jain; M. Ashquin; S. K. Tandon

    1986-01-01

    The effects of a low protein diet on the body uptake and retention of cadmium, levels of essential trace elements, and cadmium-induced biochemical alterations in liver and kidneys of the rat were investigated. Low dietary protein disturbs cadmium induced alterations in carbohydrate metabolism, essential trace elements metabolism and offsets the hepatic and renal process of cadmium detoxification. Protein malnutrition enhances

  16. Molecular Responses of Campylobacter jejuni to Cadmium Stress

    Microsoft Academic Search

    Nadeem O. Kaakoush; Mark Raftery; George L. Mendz

    2008-01-01

    Cadmium ions are a potent carcinogen in animals, and cadmium is a toxic metal of significant environmental importance for humans. Response curves were used to investigate the effects of cadmium chloride on the growth of Camplyobacter jejuni. In vitro, the bacterium showed reduced growth in the presence of 0.1 mm cadmium chloride, and the metal ions were lethal at 1

  17. Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material

    DOEpatents

    Doeff, Marca M. (Hayward, CA); Peng, Marcus Y. (Cupertino, CA); Ma, Yanping (Albany, CA); Visco, Steven J. (Berkeley, CA); DeJonghe, Lutgard C. (Lafayette, CA)

    1996-01-01

    An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M.sub.x Z.sub.y Mn.sub.(1-y) O.sub.2, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell.

  18. Fertility and content of cadmium in pheasant (Phasianus colchicus) following cadmium intake in drinking water.

    PubMed

    Toman, R; Massányi, P; Lukác, N; Ducsay, L; Golian, J

    2005-09-01

    In this study, the effects of cadmium applied per os on fertility, live weight of newly hatched chicks, and cadmium concentrations in some organs of young and adult pheasants were investigated. The metal was applied at the concentration of 1.5 mg Cd(2+)/L during 3 months. After the egg laying, the numbers of eggs laid, cracked, and unfertilized were determined and the live weights of newly hatched chicks were measured. The cadmium concentrations in liver, kidney, and muscle (m. pectoralis) of young and adult pheasants were analyzed. We found that cadmium exposure of the adults did not affect the number of eggs laid but resulted in more eggs being damaged. Hatchlings were significantly heavier in the cadmium-treated group (21.36 +/- 2.28 g) compared to the control group (20.91 +/- 1.97 g) 4 weeks after the cadmium intake. Higher cadmium concentrations were observed in the muscle and kidney tissue of newly hatched pheasants after 4 weeks compared to the cadmium-exposed groups after 8 and 12 weeks. The cadmium concentrations in kidneys and liver increased significantly in adult pheasants. The metal had accumulated especially in kidneys of the adult pheasants and reached levels up to 9.64 mg/kg wet weight 3 months after the daily cadmium intake in drinking water. The concentration in liver of the adults was 3.53 mg/kg wet weight. PMID:15978296

  19. Correcting Iron Deficiencies in Grain Sorghum

    E-print Network

    Livingston, Stephen; Coffman, Cloyce G.; Unruh, L. G.

    1996-02-20

    no agitation. PenGreen II contain an addition of 3 percent N. Several manufacturers of foliar products have constructed iron materials that also contain nitrogen, phosphorous, zinc, magnesium, and manganese, as well as other micronutrients. These additions... leaf burn, cost, ease of application, and shelf life. Rate Agitation Product Per Acre Form Required Copperas 4-5 lb. dry, coarse yes Vitatone 1.5-3 lb. dry, fine yes Chelate 1-2 lb. dry, fine yes PenGreen 3-6 qt. liquid no Using Chlorosis...

  20. Formation of ferric iron crusts in Quaternary sediments of Lake Baikal, Russia, and implications for paleoclimate

    Microsoft Academic Search

    R. G. Deike; L. Granina; E. Callender; J. J. McGee

    1997-01-01

    Phosphate-bearing, ferric iron and siliceous crusts ranging in age from Recent to approximately 65,000 yr B.P. are observed in sediments of Lake Baikal. In younger sediments the crusts are at the base of a spectrum of secondary iron and manganese oxides that accumulate near the sediment\\/water interface in the zone of positive oxidation potential beneath an oxygenated water column. In

  1. The Manganese Site of the Photosynthetic Water-Splitting Enzyme

    NASA Astrophysics Data System (ADS)

    George, Graham N.; Prince, Roger C.; Cramer, Stephen P.

    1989-02-01

    As the originator of the oxygen in our atmosphere, the photosynthetic water-splitting enzyme of chloroplasts is vital for aerobic life on the earth. It has a manganese cluster at its active site, but it is poorly understood at the molecular level. Polarized synchrotron radiation was used to examine the x-ray absorption of manganese in oriented chloroplasts. The manganese site, in the ``resting'' (S1) state, is an asymmetric cluster, which probably contains four manganese atoms, with interatomic separations of 2.7 and 3.3 angstroms; the vector formed by the 3.3-angstrom manganese pair is oriented perpendicular to the membrane plane. Comparisons with model compounds suggest that the cluster contains bridging oxide or hydroxide ligands connecting the manganese atoms, perhaps with carboxylate bridges connecting the 3.3-angstrom manganese pair.

  2. Analysis of manganese particulates from automotive decomposition of methylcyclopentadienyl manganese tricarbonyl

    Microsoft Academic Search

    C. Colmenares; Steven Deutsch; Cheryl Evans; A. J. Nelson; Louis J. Terminello; John G. Reynolds; Joseph W. Roos; Isaac L. Smith

    1999-01-01

    Particulates have been collected and analyzed from automotive vehicles operating on fuel containing the organometallic antiknock additive methylcyclopentadienyl manganese tricarbonyl. Electron spectroscopy for chemical analysis and L-edge X-ray absorption spectroscopy were used to study and identify the manganese species present in these emitted particulates. Results show that respirable size particulates with a mass median aerodynamic diameter of 2.5 ?m or

  3. Comparative Toxicokinetics of Manganese Chloride and Methylcyclopentadienyl Manganese Tricarbonyl (MMT) in Sprague-Dawley Rats

    Microsoft Academic Search

    Wei Zheng; Hyaehwan Kim; Qiuqu Zhao

    2000-01-01

    The toxicokinetics of manganese (Mn) was investigated in male and female rats either following a single intravenous (iv) or oral dose of MnCl2 (6.0 mg Mn\\/kg), or following a single oral dose of methylcyclopentadienyl manganese tricarbonyl (MMT) (20 mg MMT\\/kg or 5.6 mg Mn\\/kg). The plasma concentrations of man- ganese were quantified by atomic absorption spectrophotometry (AAS). Upon iv administration

  4. Bacterial iron homeostasis

    Microsoft Academic Search

    Simon C Andrews; Andrea K Robinson; Francisco Rodr??guez-Quiñones

    2003-01-01

    Iron is essential to virtually all organisms, but poses problems of toxicity and poor solubility. Bacteria have evolved various mechanisms to counter the problems imposed by their iron dependence, allowing them to achieve effective iron homeostasis under a range of iron regimes. Highly efficient iron acquisition systems are used to scavenge iron from the environment under iron-restricted conditions. In many

  5. Analysis of the world distribution of metal-rich subsea manganese nodules

    USGS Publications Warehouse

    McKelvey, Vincent Ellis; Wright, Nancy A.; Bowen, Roger W.

    1983-01-01

    Publicly available data on the composition of subsea manganese nodules extend previous reports of differences in average metal contents from ocean to ocean and of variations related to latitude and depth. Pacific Ocean nodules have the highest average manganese, nickel, and copper contents, and Atlantic Ocean nodules have the highest average iron content. The average manganese, nickel, and copper contents generally increase toward the equator in both hemispheres, and iron content generally decreases. The variation of metal content with water depth is not linear; instead, there appears to be a threshold depth of about 2,900 to 3,000 m, above which combined nickel and copper contents are generally less than 1 percent and below which cobalt content is generally less than about 0.6 percent. The composition of the nodules varies widely, but three rarely overlapping types that are of possible economic interest can be recognized. (1) Nodules containing more than about 1 percent combined nickel and copper only exceptionally contain more than 0.5 percent cobalt and 35 percent manganese. (2) Nodules containing more than 0.5 percent cobalt rarely contain more than 1 percent combined nickel and copper and 35 percent manganese. (3) Nodules containing more than 35 percent manganese only exceptionally contain more than 0.5 percent cobalt, although they average nearly 1.1 percent combined nickel and copper. Current economic interest in nodule mining is focused on the Clarion-Clipperton zone in the northeastern equatorial Pacific Ocean, the largest known area in which nodules average 1.8 percent or more combined nickel and copper. Several other areas in which nodules are rich in these metals are found in the Pacific and Indian Oceans and may be viewed as targets for exploration. Nearly 60 chemical elements have been found in manganese nodules, many in concentrations far exceeding their crustal abundances. The amounts in which many minor elements are present vary with the amounts of principal metals present, but the three metal types described above do not include the maximum reported values for several other elements, such as titanium (8.9 percent), vanadium (0.5), zinc (9.0), and lead (0.75). It seems possible, therefore, that there may be other kinds of metal-rich types, some of which may have p6tential economic value. Many of the variations in nodule composition are in large part a function of variations in mineral composition, to which many factors contribute. Some of the regional variations can be broadly related to oceanic circulation, basin morphology, and depth, but a better understanding of ocean processes and regional oceanography and geology is needed to explain all the variations observed in the composition of manganese nodules.

  6. Health and environmental testing of manganese exhaust products from use of methylcyclopentadienyl manganese tricarbonyl in gasoline.

    PubMed

    Pfeifer, G D; Roper, J M; Dorman, D; Lynam, D R

    2004-12-01

    This paper reviews recent research on the environmental effects of methylcyclopentadienyl manganese tricarbonyl (MMT), personal exposures to airborne Mn as a result of MMT use, chemical characterization of the manganese particulates emitted from the tailpipe and progress in developing a (PBPK) model for manganese in rodents. Recent studies show that manganese is emitted as a mixture of compounds with an average valence of about 2.2. The major products are sulfate, phosphate, and smaller amounts of oxides. Because only small amounts of Mn are used in gasoline (<18 mg Mn/gal) and less than 15% of the combusted Mn is emitted, soil along busy roads is not elevated in Mn, even after long-term use of MMT. A very large population-based study of manganese exposures in the general population in Toronto, where MMT has been used continuously for over 20 years, showed that manganese exposures were quite low, the median annual exposure was 0.008 microg Mn/m(3). A great amount of toxicological research on Mn has been carried out during the past few years that provides data for use in developing a PBPK model in rodents. These data add greatly to the existing body of knowledge regarding the relationship between Mn exposure and tissue disposition. When complete, the PBPK model will contribute to our better understanding of the essential neurotoxic dynamics of Mn. PMID:15504525

  7. Soil manganese enrichment from industrial inputs: a gastropod perspective.

    PubMed

    Bordean, Despina-Maria; Nica, Dragos V; Harmanescu, Monica; Banatean-Dunea, Ionut; Gergen, Iosif I

    2014-01-01

    Manganese is one of the most abundant metal in natural environments and serves as an essential microelement for all living systems. However, the enrichment of soil with manganese resulting from industrial inputs may threaten terrestrial ecosystems. Several studies have demonstrated harmful effects of manganese exposure by cutaneous contact and/or by soil ingestion to a wide range of soil invertebrates. The link between soil manganese and land snails has never been made although these invertebrates routinely come in contact with the upper soil horizons through cutaneous contact, egg-laying, and feeding activities in soil. Therefore, we have investigated the direct transfer of manganese from soils to snails and assessed its toxicity at background concentrations in the soil. Juvenile Cantareus aspersus snails were caged under semi-field conditions and exposed first, for a period of 30 days, to a series of soil manganese concentrations, and then, for a second period of 30 days, to soils with higher manganese concentrations. Manganese levels were measured in the snail hepatopancreas, foot, and shell. The snail survival and shell growth were used to assess the lethal and sublethal effects of manganese exposure. The transfer of manganese from soil to snails occurred independently of food ingestion, but had no consistent effect on either the snail survival or shell growth. The hepatopancreas was the best biomarker of manganese exposure, whereas the shell did not serve as a long-term sink for this metal. The kinetics of manganese retention in the hepatopancreas of snails previously exposed to manganese-spiked soils was significantly influenced by a new exposure event. The results of this study reveal the importance of land snails for manganese cycling in terrestrial biotopes and suggest that the direct transfer from soils to snails should be considered when precisely assessing the impact of anthropogenic Mn releases on soil ecosystems. PMID:24454856

  8. Metallurgy and Processing of Marine Manganese Nodules

    Microsoft Academic Search

    D. W. FUERSTENAU; K. N. HAN

    1983-01-01

    This paper reviews the state of the art in processing and extraction of ocean floor manganese nodules. It briefly reviews the mining sites where the abundant rich nodules occur and also discusses the metal distribution in nodules in view of economical processing and extraction of these metal values.The paper discloses in a detailed manner the physical and chemical characteristics of

  9. Lithium Manganese Silicate Positive Electrode Material

    NASA Astrophysics Data System (ADS)

    Yang, Qiong

    As the fast development of the electronic portable devices and drastic fading of fossil energy sources. The need for portable secondary energy sources is increasingly urgent. As a result, lithium ion batteries are being investigated intensely to meet the performance requirements. Among various electrode materials, the most expensive and capacity limiting component is the positive materials. Based on this, researches have been mostly focused on the development of novel cathode materials with high capacity and energy density and the lithium transition metal orthosilicates have been identified as possible high performance cathodes. Here in, we report the synthesis of a kind of lithium transition metal orthosilicates electrode lithium manganese silicate. Lithium manganese silicate has the advantage of high theoretical capacity, low cost raw material and safety. In this thesis, lithium manganese silicate are prepared using different silicon sources. The structure of silicon sources preferred are examined. Nonionic block copolymers surfactant, P123, is tried as carbon source and mophology directing agent. Lithium manganese silicate's performances are improved by adding P123.

  10. Environmental fate of methylcyclopentadienyl manganese tricarbonyl

    Microsoft Academic Search

    Arthur W. Garrison; N. L. Wolfe; R. R. Jr. Swank; M. G. Cipollone

    1995-01-01

    Methylcyclopentadienyl manganese tricarbonyl (MMT) has been proposed as an octane booster for unleaded gasoline; such use could result in ecological and human exposure through surface water and groundwater ecosystems. To evaluate the environmental risks from MMT, its environmental fate constants and transformation pathways must be known. Constants for physical parameters that would likely influence MMT fate were collected from the

  11. 21 CFR 184.1461 - Manganese sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...No. 7785-0987-097) is a pale pink, granular, odorless powder. It is obtained by reacting manganese compounds with sulfuric...products as defined in § 170.3(n)(29) of this chapter; milk products as defined in § 170.3(n)(31) of this...

  12. 21 CFR 184.1449 - Manganese citrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Reg. No. 1002-46-65) is a pale orange or pinkish white powder. It is obtained by precipitating manganese carbonate from...products as defined in § 170.3(n)(29) of this chapter; milk products as defined in § 170.3(n)(31) of this...

  13. 21 CFR 184.1452 - Manganese gluconate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...CAS Reg. No. 648-0953-0998) is a slightly pink colored powder. It is obtained by reacting manganese carbonate with gluconic...products as defined in § 170.3(n)(29) of this chapter; milk products as defined in § 170.3(n)(31) of this...

  14. Chemically activated manganese dioxide for dry batteries

    NASA Astrophysics Data System (ADS)

    Askar, M.; Abbas, H.

    1994-10-01

    The present investigation has enabled us to convert inactive beta-manganese dioxide to high electrochemically active types by chemical processes. Natural and chemically prepared beta-manganese dioxides were roasted at 1050 C to form Mn3O4. This compound was subjected to activation treatment using hydrochloric and sulfuric acid under various reaction conditions. The manganese dioxide so obtained was examined by x-ray diffraction, thermogravimetric, differential thermal, and chemical analyses. The structure of the dioxide obtained was found to be greatly dependent on the origin of MnO2 and type of acid used. Treatment with hydrochloric acid yielded the so-called gamma-variety while sulfuric acid tended to produce gamma- or alpha-MnO2. In addition, waste manganese sulfate obtained as by-product from sulfuric acid digestion treatment was recycled and electrolytically oxidized to gamma-MnO2. The discharge performance of the above-mentioned MnO2 samples as battery cathodic active material was evaluated and compared with the ordinary battery grade.

  15. Magnetic and orbital excitations in manganese oxides

    Microsoft Academic Search

    W. Koshibae; S. Ishihara; Y. Kawamura; S. Okamoto; J. Inoue; S. Maekawa

    1997-01-01

    The magnetic and orbital structures in manganese oxides with perovskite structure are examined by using the exact diagonalization method on finite-size clusters. The orbital degeneracy in the eg states is taken into account based on the effective Hamiltonian derived in the insulating state with strong Coulomb interaction. It is shown that A-, C- and G-type antiferromagnetic ordering occur as a

  16. Olfactory impairment after chronic occupational cadmium exposure.

    PubMed

    Rose, C S; Heywood, P G; Costanzo, R M

    1992-06-01

    Disorders of olfaction affect millions of Americans, but the extent to which occupational and environmental exposures contribute to these disorders is unknown. We examined 55 workers with chronic occupational exposure to cadmium fumes in a brazing operation. We estimated cadmium body burden using urinary cadmium levels and assessed cadmium-induced renal damage by urinary beta 2-microglobulin levels. We quantified olfactory function using a standardized test that measured two components of olfaction, butanol detection threshold and odor identification, and compared workers with a reference group. Forty-four percent of the cadmium-exposed workers were mildly hyposmic, and 13% were either moderately or severely hyposmic. In the reference group, 31% were mildly hyposmic, and the rest were normosmic. The workers with both high urinary cadmium levels and tubular proteinuria had the most significant olfactory dysfunction, with a selective defect in odor detection threshold. Our findings suggest that chronic occupational cadmium exposure sufficient to cause renal damage also is associated with impairment in olfactory function. PMID:1619490

  17. Cadmium determination in Mexican-produced tobacco

    SciTech Connect

    Saldivar De R., L.; Soto, R.; Fortoul, T.I. (Univ. Nacional Autonoma de Mexico, Mexico City (Mexico)); Luna, M.; Reyes, E. (Secretaria de Mejoramiento del Ambiente, Mexico City (Mexico))

    1991-06-01

    Exposure to cadmium by inhalation or ingestion is dangerous for human health. This metal induces damage to the kidneys, the bones, the prostate, and the lungs. In the lungs, cadmium can produce cancer, emphysema, and fibrosis. It is well known that tobacco leaves are contaminated with cadmium, a metal that has been related to pulmonary damage. In this paper the authors report the concentration of cadmium in tobacco leaves and in cigarettes produced for domestic consumption. Fifty-five cigarettes of different brands, prices, and stocks were analyzed as well as 48 samples from four different types of tobacco. The average concentration of cadmium in cigarettes was 4.41 {plus minus} 0.67 {mu}g/g, and 2.65 {plus minus} 0.99 {mu}g/g for tobacco leaves; the content of cadmium, was 2.8 {plus minus} 0.4 {mu}g/cigarette. It was estimated that a person that smokes 20 Mexican cigarettes per day can increase his(her) cadmium burden by 1.4 to 2.8 {mu}g per day.

  18. Process for producing large grain cadmium telluride

    DOEpatents

    Hasoon, F.S.; Nelson, A.J.

    1996-01-16

    A process is described for producing a cadmium telluride polycrystalline film having grain sizes greater than about 20 {micro}m. The process comprises providing a substrate upon which cadmium telluride can be deposited and placing that substrate within a vacuum chamber containing a cadmium telluride effusion cell. A polycrystalline film is then deposited on the substrate through the steps of evacuating the vacuum chamber to a pressure of at least 10{sup {minus}6} torr.; heating the effusion cell to a temperature whereat the cell releases stoichiometric amounts of cadmium telluride usable as a molecular beam source for growth of grains on the substrate; heating the substrate to a temperature whereat a stoichiometric film of cadmium telluride can be deposited; and releasing cadmium telluride from the effusion cell for deposition as a film on the substrate. The substrate then is placed in a furnace having an inert gas atmosphere and heated for a sufficient period of time at an annealing temperature whereat cadmium telluride grains on the substrate grow to sizes greater than about 20 {micro}m.

  19. Cadmium-induced infertility in male mice.

    PubMed

    Monsefi, Malihezaman; Alaee, Sanaz; Moradshahi, Ali; Rohani, Lahya

    2010-02-01

    The effects of cadmium in a concentration similar to that found in Maharloo Lake (Shiraz, Iran) on male reproductive system was studied in adult Balb/c male mice that received 0, 23, and 50 mg/kg of cadmium chloride in 0.5 mL distilled water for 45 days. Sperm count and motility, sperm nuclear maturity and chromatin structure tests were carried out. Testis of each mouse was examined histologically. The treated male mice were mated with females. Prostatic and nonprostatic acid phosphatase activity in blood serum, testis, and prostate, lipid peroxidation and cadmium accumulation in testis, seminal vesicle, and middle 1/3 of the quadericeps femoris muscle were measured. The sperm count, sperm motility, sperm maturity, and the level of testosterone decreased significantly in the high dose adminstered group. Histological studies showed a severe necrosis and atrophy in the testis of high dose group, consequently, there was no successful mating in some groups. The number of newborns and their weights and crown rump lengths reduced. Cadmium accumulation in testis and middle of the quadriceps femoris muscle was significantly higher in animals receiving 50 mg/kg cadmium chloride. Nonprostatic acid phosphatase activity decreased, whereas prostatic acid phosphatase activity increased significantly in serum of animals receiving 50 mg/kg cadmium chloride. Also prostatic acid phosphatase activity decreased significantly in prostate of animals receiving 50 mg/kg cadmium chloride. Lipid peroxidation was significantly higher in testis of animals treated with 50 mg/kg cadmium chloride compared with control group. Cadmium affects male reproductive system activity and can cause infertility in mice as an animal model. PMID:19161232

  20. An Assessment of the Natural and Anthropogenic Geochemistry of the Red Mountain Creek Watershed: Ironton Mining District, Colorado

    E-print Network

    Litt, Joshua

    2014-04-29

    of remediation. Water quality data were collected for Aluminum (Al), Cadmium (Cd), Copper (Cu), Iron (Fe), Lead (Pb), Magnesium (Mg), Manganese (Mn), Zinc (Zn), and temperature, specific conductance, pH and dissolved oxygen. Twenty-seven samples were filtered...

  1. An Assessment of the Natural and Anthropogenic Geochemistry of the Red Mountain Creek Watershed: Ironton Mining District, Colorado 

    E-print Network

    Litt, Joshua

    2014-04-29

    of remediation. Water quality data were collected for Aluminum (Al), Cadmium (Cd), Copper (Cu), Iron (Fe), Lead (Pb), Magnesium (Mg), Manganese (Mn), Zinc (Zn), and temperature, specific conductance, pH and dissolved oxygen. Twenty-seven samples were filtered...

  2. Disruption of sitA Compromises Sinorhizobium meliloti for Manganese Uptake Required for Protection against Oxidative Stress?

    PubMed Central

    Davies, Bryan W.; Walker, Graham C.

    2007-01-01

    During the initial stages of symbiosis with the host plant Medicago sativa, Sinorhizobium meliloti must overcome an oxidative burst produced by the plant in order for proper symbiotic development to continue. While identifying mutants defective in symbiosis and oxidative stress defense, we isolated a mutant with a transposon insertion mutation of sitA, which encodes the periplasmic binding protein of the putative iron/manganese ABC transporter SitABCD. Disruption of sitA causes elevated sensitivity to the reactive oxygen species hydrogen peroxide and superoxide. Disruption of sitA leads to elevated catalase activity and a severe decrease in superoxide dismutase B (SodB) activity and protein level. The decrease in SodB level strongly correlates with the superoxide sensitivity of the sitA mutant. We demonstrate that all free-living phenotypes of the sitA mutant can be rescued by the addition of exogenous manganese but not iron, a result that strongly implies that SitABCD plays an important role in manganese uptake in S. meliloti. PMID:17172335

  3. Selective removal of iron contaminations from zinc-chloride melts by cementation with zinc

    Microsoft Academic Search

    R. A. Devilee; A. Van Sandwijk; M. A. Reuter

    1999-01-01

    An investigation into the cementation of iron chloride from a zinc-chloride melt at 400 °C has been carried out with zinc\\u000a powder. The variables studied include preparation of the chloride melt and the amount of zinc added. The effect of lead, copper,\\u000a and cadmium on cementation of iron has also been investigated. According to the results, it is possible to

  4. Iron promotes protein insolubility and aging in C. elegans

    PubMed Central

    Klang, Ida M.; Schilling, Birgit; Sorensen, Dylan J.; Sahu, Alexandria K.; Kapahi, Pankaj; Andersen, Julie K.; Swoboda, Peter; Killilea, David W.; Gibson, Bradford W.; Lithgow, Gordon J.

    2014-01-01

    Many late-onset proteotoxic diseases are accompanied by a disruption in homeostasis of metals (metallostasis) including iron, copper and zinc. Although aging is the most prominent risk factor for these disorders, the impact of aging on metallostasis and its role in proteotoxic disease remain poorly understood. Moreover, it is not clear whether a loss of metallostasis influences normal aging. We have investigated the role of metallostasis in longevity of Caenorhabditis elegans. We found that calcium, copper, iron, and manganese levels increase as a function of age, while potassium and phosphorus levels tend to decrease. Increased dietary iron significantly accelerated the age-related accumulation of insoluble protein, a molecular pathology of aging. Proteomic analysis revealed widespread effects of dietary iron in multiple organelles and tissues. Pharmacological interventions to block accumulation of specific metals attenuated many models of proteotoxicity and extended normal lifespan. Collectively, these results suggest that a loss of metallostasis with aging contributes to age-related protein aggregation. PMID:25554795

  5. The effect of humic acids on iron precipitation

    SciTech Connect

    Koschalk, N.M.; Fish, C.L. [St. Vincent College, Latrobe, PA (United States)

    1995-12-01

    Research involving the passive treatment of abandoned mine drainage and iron precipitation was conducted. The rate of iron precipitation from an alkaline mine drainage site in Latrobe, PA increases naturally whenever it comes in contact with Monastery Run, a stream in Latrobe, PA which is high in humic acids. To study the extent of humic acids` effect on the precipitation of metals from alkaline mine drainage, the rate of precipitation of iron, magnesium, manganese, and calcium was monitored after either Monastery Run water or Aldrich Humics were added to the alkaline mine drainage water. The rate of iron Precipitation did increase when Monastery Run water and Aldrich Humics were added to the alkaline mine drainage water. Different parameters which were studied along with the effect of humics on the precipitation of metals were concentration, ionic strength and alkalinity.

  6. Influence of groundwater composition on subsurface iron and arsenic removal.

    PubMed

    Moed, D H; van Halem, D; Verberk, J Q J C; Amy, G L; van Dijk, J C

    2012-01-01

    Subsurface arsenic and iron removal (SAR/SIR) is a novel technology to remove arsenic, iron and other groundwater components by using the subsoil. This research project investigated the influence of the groundwater composition on subsurface treatment. In anoxic sand column experiments, with synthetic groundwater and virgin sand, it was found that several dissolved substances in groundwater compete for adsorption sites with arsenic and iron. The presence of 0.01 mmol L(-1) phosphate, 0.2 mmol L(-1) silicate, and 1 mmol L(-1) nitrate greatly reduced the efficiency of SAR, illustrating the vulnerability of this technology in diverse geochemical settings. SIR was not as sensitive to other inorganic groundwater compounds, though iron retardation was limited by 1.2 mmol L(-1) calcium and 0.06 mmol L(-1) manganese. PMID:22678215

  7. The effects of histidine on the uptake of cadmium from the digestive system of the blue crab (Callinectes sapidus, Rathbun) 

    E-print Network

    Pecon, Jill Maureen

    1980-01-01

    with the metal (Zolotov, 1970). Van Campen (1973) showed that histidine, cysteine, and lysins keep the metal in solution by forming ligands with iron in rat intestine. Histidine is capable of forming chelates with metal iona in the ratio of one molecule..., the assay is conducted under stable, regulated laboratory conditions whereas the fluctuating physical para- meters of the coastal environment can influence the response of the animal being examined. For example, cadmium was found to be more th* f'ddl * 3...

  8. Distribution and Enrichment of Silver and Cadmium in Coastal Sediments from Bahía Todos Santos, Baja California, México

    Microsoft Academic Search

    E. A. Gutiérrez-Galindo; A. Muñoz-Barbosa; M. R. Mandujano-Velasco; L. W. Daesslé; M. V. Orozco Borbón

    2010-01-01

    Silver, cadmium and iron were studied in sediment from Bahia Todos Santos, Baja California, México during 2004. Results showed\\u000a that the spatial distributions of these metals were very similar to that of organic carbon and fine grain size, with values\\u000a increasing from the inner to the outer parts of the bay. High concentrations and enrichments of silver (0.051–0.071 ?g g?1 dry weight)

  9. A simple route to synthesize manganese germanate nanorods

    SciTech Connect

    Pei, L.Z., E-mail: lzpei1977@163.com; Yang, Y.; Yuan, C.Z.; Duan Taike; Zhang Qianfeng

    2011-06-15

    Manganese germanate nanorods have been synthesized by a simple route using germanium dioxide and manganese acetate as the source materials. X-ray diffraction observation shows that the nanorods are composed of orthorhombic and monoclinic manganese germanate phases. Scanning electron microscopy and transmission electron microscopy observations display that the manganese germanate nanorods have flat tips with the length of longer than 10 micrometers and diameter of 60-350 nm, respectively. The role of the growth conditions on the formation of the manganese germanate nanorods shows that the proper selection and combination of the growth conditions are the key factor for controlling the formation of the manganese germanate nanorods. The photoluminescence spectrum of the manganese germanate nanorods exhibits four fluorescence emission peaks centered at 422 nm, 472 nm, 487 nm and 530 nm showing the application potential for the optical devices. - Research Highlights: {yields} Manganese germanate nanorods have been synthesized by simple hydrothermal process. {yields} The formation of manganese germanate nanorods can be controlled by growth conditions. {yields} Manganese germanate nanorods exhibit good PL emission ability for optical device.

  10. Cellular manganese content is developmentally regulated in human dopaminergic neurons

    NASA Astrophysics Data System (ADS)

    Kumar, Kevin K.; Lowe, Edward W., Jr.; Aboud, Asad A.; Neely, M. Diana; Redha, Rey; Bauer, Joshua A.; Odak, Mihir; Weaver, C. David; Meiler, Jens; Aschner, Michael; Bowman, Aaron B.

    2014-10-01

    Manganese (Mn) is both an essential biological cofactor and neurotoxicant. Disruption of Mn biology in the basal ganglia has been implicated in the pathogenesis of neurodegenerative disorders, such as parkinsonism and Huntington's disease. Handling of other essential metals (e.g. iron and zinc) occurs via complex intracellular signaling networks that link metal detection and transport systems. However, beyond several non-selective transporters, little is known about the intracellular processes regulating neuronal Mn homeostasis. We hypothesized that small molecules that modulate intracellular Mn could provide insight into cell-level Mn regulatory mechanisms. We performed a high throughput screen of 40,167 small molecules for modifiers of cellular Mn content in a mouse striatal neuron cell line. Following stringent validation assays and chemical informatics, we obtained a chemical `toolbox' of 41 small molecules with diverse structure-activity relationships that can alter intracellular Mn levels under biologically relevant Mn exposures. We utilized this toolbox to test for differential regulation of Mn handling in human floor-plate lineage dopaminergic neurons, a lineage especially vulnerable to environmental Mn exposure. We report differential Mn accumulation between developmental stages and stage-specific differences in the Mn-altering activity of individual small molecules. This work demonstrates cell-level regulation of Mn content across neuronal differentiation.

  11. Cellular manganese content is developmentally regulated in human dopaminergic neurons

    PubMed Central

    Kumar, Kevin K.; Lowe, Jr., Edward W.; Aboud, Asad A.; Neely, M. Diana; Redha, Rey; Bauer, Joshua A.; Odak, Mihir; Weaver, C. David; Meiler, Jens; Aschner, Michael; Bowman, Aaron B.

    2014-01-01

    Manganese (Mn) is both an essential biological cofactor and neurotoxicant. Disruption of Mn biology in the basal ganglia has been implicated in the pathogenesis of neurodegenerative disorders, such as parkinsonism and Huntington's disease. Handling of other essential metals (e.g. iron and zinc) occurs via complex intracellular signaling networks that link metal detection and transport systems. However, beyond several non-selective transporters, little is known about the intracellular processes regulating neuronal Mn homeostasis. We hypothesized that small molecules that modulate intracellular Mn could provide insight into cell-level Mn regulatory mechanisms. We performed a high throughput screen of 40,167 small molecules for modifiers of cellular Mn content in a mouse striatal neuron cell line. Following stringent validation assays and chemical informatics, we obtained a chemical ‘toolbox' of 41 small molecules with diverse structure-activity relationships that can alter intracellular Mn levels under biologically relevant Mn exposures. We utilized this toolbox to test for differential regulation of Mn handling in human floor-plate lineage dopaminergic neurons, a lineage especially vulnerable to environmental Mn exposure. We report differential Mn accumulation between developmental stages and stage-specific differences in the Mn-altering activity of individual small molecules. This work demonstrates cell-level regulation of Mn content across neuronal differentiation. PMID:25348053

  12. High efficiency cadmium and zinc telluride-based thin film solar cells

    SciTech Connect

    Rohatgi, A.; Summers, C.J.; Erbil, A.; Sudharsanan, R.; Ringel, S. (Georgia Inst. of Tech., Atlanta, GA (USA). School of Electrical Engineering)

    1990-10-01

    Polycrystalline Cd{sub 1-x}Zn{sub x}Te and Cd{sub 1-x}Mn{sub x}Te films with a band gap of 1.7 eV were successfully grown on glass/SnO{sub 2}/CdS substrates by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD), respectively. Polycrystalline Cd{sub 1-x}Zn{sub x}Te films grown by MBE resulted in uniform composition and sharp interfaces. However, polycrystalline Cd{sub 1-x}Mn{sub x}Te films grown by MOCVD showed nonuniform compositions and evidence of manganese accumulation at the Cd{sub 1-x}Mn{sub x}Te/CdS interface. We found that manganese interdiffuses and replaces cadmium in the CdS film. By improving the CdTe/CdS interface and, thus, reducing the collection function effects, the efficiency of the MOCVD CdTe cell can be improved to about 13.5%. MBE-grown CdTe cells also produced 8%--9% efficiencies. The standard CdTe process was not optimum for ternary films and resulted in a decrease in the band gap. Recent results indicate that CdCl{sub 2} + ZnCl{sub 2} chemical treatment may prevent the band-gap reduction, and that chromate etch (rather than bromine etch) may provide the solution to contact resistance in the ternary cells.

  13. An Iron and Fur-RepressedLegionella pneumophilaGene That Promotes Intracellular Infection and Encodes a Protein with Similarity to theEscherichia coliAerobactin Synthetases

    Microsoft Academic Search

    ERIN K. HICKEY; ANDNICHOLAS P. CIANCIOTTO

    1997-01-01

    L. pneumophila furcould not be insertionally inactivated, but spontaneous Fur2derivatives were generated by selecting for manganese resistance. Strain NU229 contained a Fur-repressed fusion based on derepression of lacZexpression in its manganese-resistant derivative. Extracellular growth of NU229 in bacteriological media was similar to that of wild-type strain 130b. To assess the role of an iron- and Fur-regulated (frgA) gene in intracellular

  14. The distribution of potentially toxic heavy metals in the sediments of San Antonio Bay and the northwest Gulf of Mexico 

    E-print Network

    Trefry, John Harold

    1974-01-01

    total of 123 sediment samples from 48 locations in the northwest Gulf of Mexico, including San Antonio Bay and the Mississippi River Delta, were acid leached and analyzed for iron, manganese, lead, zinc, cadmium, copper, and nickel by atomic... total of 123 sediment samples from 48 locations in the northwest Gulf of Mexico, including San Antonio Bay and the Mississippi River Delta, were acid leached and analyzed for iron, manganese, lead, zinc, cadmium, copper, and nickel by atomic...

  15. Effect of cadmium on meiosis. [Rats

    SciTech Connect

    Fowler, A.J.; Singh, D.N.; Dwivedi, C.

    1982-10-01

    Adult male albino Sprague-Dawley rats were injected with cadmium as cadmium chloride at dosages of 5 and 10 ..mu..moles/kg. After sacrifice, testes were removed and cells prepared for microscopic analysis. Counts of chromosome number at dysjunction or precocious separation of homologous and sex chromosomes were made. The degeneration of sex vesicles at early prophase and tetraploid cells at metaphase I and II was scored and compared with control data. At least three hundred cells were counted from each slide. Results indicate that cadmium produces degeneration of sex vesicles, precocious separation of sex chromosomes, and tetraploidy. Increased occurrence was observed at 72 hours after cadmium injection and at the higher dosage of 10 ..mu..moles/kg compared with a post-injection time of 48 hours and a dosage of 5 ..mu..moles/kg. However, a significant tetraploidy was observed only at 10 ..mu..moles/kg. (JMT)

  16. Floating zone melting of cadmium telluride

    NASA Technical Reports Server (NTRS)

    Chang, Wen-Ming; Regel, L. L.; Wilcox, W. R.

    1992-01-01

    To produce superior crystals of cadmium telluride, floating zone melting in space has been proposed. Techniques required for floating zone melting of cadmium telluride are being developed. We have successfully float-zoned cadmium telluride on earth using square rods. A resistance heater was constructed for forming the molten zone. Evaporation of the molten zone was controlled by adding excess cadmium to the growth ampoule combined with heating of the entire ampoule. An effective method to hold the feed rod was developed. Slow rotation of the growth ampoule was proven experimentally to be necessary to achieve a complete symmetric molten zone. Most of the resultant cylindrical rods were single crystals with twins. Still needed is a suitable automatic method to control the zone length. We tried a fiber optical technique to control the zone length, but experiments showed that application of this technique to automate zone length control is unlikely to be successful.

  17. RISK ASSESSMENT AND MANAGEMENT OF ENVIRONMENTAL CADMIUM

    EPA Science Inventory

    Cadmium consumed in foods grown on soils contaminated by industrial Cd+Zn discharge has caused renal tubular dysfunction in exposed humans in discrete situations. However, lack of understanding about environmental Cd has caused wide concern that general populations may...

  18. Iron and alloys of iron. [lunar resources

    NASA Technical Reports Server (NTRS)

    Sastri, Sankar

    1992-01-01

    All lunar soil contains iron in the metallic form, mostly as an iron-nickel alloy in concentrations of a few tenths of 1 percent. Some of this free iron can be easily separated by magnetic means. It is estimated that the magnetic separation of 100,000 tons of lunar soil would yield 150-200 tons of iron. Agglutinates contain metallic iron which could be extracted by melting and made into powder metallurgy products. The characteristics and potential uses of the pure-iron and iron-alloy lunar products are discussed. Processes for working iron that might be used in a nonterrestrial facility are also addressed.

  19. Cadmium Exposure and Incident Peripheral Arterial Disease

    PubMed Central

    Tellez-Plaza, Maria; Guallar, Eliseo; Fabsitz, Richard R.; Howard, Barbara V.; Umans, Jason G.; Francesconi, Kevin A.; Goessler, Walter; Devereux, Richard B.; Navas-Acien, Ana

    2014-01-01

    Background Cadmium has been associated with peripheral arterial disease in cross-sectional studies but prospective evidence is lacking. Our goal was to evaluate the association of urine cadmium concentrations with incident peripheral arterial disease in a large population-based cohort. Methods and Results A prospective cohort study was performed with 2,864 adult American Indians 45-74 years old from Arizona, Oklahoma and North and South Dakota who participated in the Strong Heart Study in 1989-91 and were followed through two follow-up examination visits in 1993-1995 and 1997-1999. Participants were free of peripheral arterial disease, defined as an ankle brachial index <0.9 or >1.4, at baseline and had complete baseline information on urine cadmium, potential confounders and ankle brachial index determinations in the follow-up examinations. Urine cadmium was measured using inductively coupled plasma mass spectrometry (ICPMS) and corrected for urinary dilution by normalization to urine creatinine.. Multivariable-adjusted hazard ratios (HR) were computed using Cox-proportional hazards models for interval-censored data. A total of 470 cases of incident peripheral arterial disease, defined as an ankle brachial index <0.9 or >1.4, were identified. After adjustment for cardiovascular disease risk factors including smoking status and pack-years, the hazard ratio comparing the 80th to the 20th percentile of urine cadmium concentrations was 1.41 (1.05, 1.81). The hazard ratio comparing the highest to the lowest tertile was 1.96 (1.32, 2.81). The associations persisted after excluding participants with ankle brachial index > 1.4 only as well as in subgroups defined by sex and smoking status. Conclusions Urine cadmium, a biomarker of long-term cadmium exposure, was independently associated with incident peripheral arterial disease, providing further support for cadmium as a cardiovascular disease risk factor. PMID:24255048

  20. Cadmium Exposure and Incident Cardiovascular Disease

    PubMed Central

    Tellez-Plaza, Maria; Guallar, Eliseo; Howard, Barbara V.; Umans, Jason G.; Francesconi, Kevin A.; Goessler, Walter; Silbergeld, Ellen K.; Devereux, Richard B.; Navas-Acien, Ana

    2014-01-01

    Background Cadmium is a widespread toxic metal with potential cardiovascular effects, but no studies have evaluated cadmium and incident cardiovascular disease. We evaluated the association of urine cadmium concentration with cardiovascular disease incidence and mortality in a large population-based cohort. Methods We conducted a prospective cohort study of 3,348 American Indian adults aged 45–74 years from Arizona, Oklahoma and North and South Dakota who participated in the Strong Heart Study in 1989–1991. Urine cadmium was measured using inductively coupled plasma mass spectrometry. Follow-up extended through 31 December 2008. Results The geometric mean cadmium level in the study population was 0.94 ?g/g (95% confidence interval= 0.92 – 0.93). We identified 1,084 cardiovascular events, including 400 deaths. After adjustment for sociodemographic and cardiovascular risk factors, the hazard ratios (comparing the 80th to the 20th percentile of urine cadmium concentrations) was 1.43 for cardiovascular mortality (95% confidence interval=1.21 – 1.70), and 1.34 for coronary heart disease mortality (1.10 – 1.63). The corresponding hazard ratios for incident cardiovascular disease, coronary heart disease, stroke, and heart failure were 1.24 (1.11 – 1.38), 1.22 (1.08 – 1.38), 1.75 (1.17 – 2.59) and 1.39 (1.01 – 1.94), respectively. The associations were similar in most study subgroups including never-smokers. Conclusions Urine cadmium, a biomarker of long-term exposure, was associated with increased cardiovascular mortality and with increased incidence of cardiovascular disease. These findings support that cadmium exposure is a cardiovascular risk factor. PMID:23514838