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Sample records for cadmium iron manganese

  1. 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.

  2. Low iron stores are related to higher blood concentrations of manganese, cobalt and cadmium in non-smoking, Norwegian women in the HUNT 2 study

    SciTech Connect

    Margrete Meltzer, Helle; Lise Brantsaeter, Anne; Borch-Iohnsen, Berit; Ellingsen, Dag G.; Alexander, Jan; Thomassen, Yngvar; Stigum, Hein; Ydersbond, Trond A.

    2010-07-15

    Low iron (Fe) stores may influence absorption or transport of divalent metals in blood. To obtain more knowledge about such associations, the divalent metal ions cadmium (Cd), manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn) and lead (Pb) and parameters of Fe metabolism (serum ferritin, haemoglobin (Hb) and transferrin) were investigated in 448 healthy, menstruating non-smoking women, age 20-55 years (mean 38 years), participating in the Norwegian HUNT 2 study. The study population was stratified for serum ferritin: 257 were iron-depleted (serum ferritin <12 {mu}g/L) and 84 had iron deficiency anaemia (serum ferritin <12 {mu}g/L and Hb<120 g/L). The low ferritin group had increased blood concentrations of Mn, Co and Cd but normal concentrations of Cu, Zn and Pb. In multiple regression models, ferritin emerged as the main determinant of Mn, Co and Cd (p<0.001), while no significant associations with Cu, Zn and Pb were found. Adjusted r{sup 2} for the models were 0.28, 0.48 and 0.34, respectively. Strong positive associations between blood concentrations of Mn, Co and Cd were observed, also when controlled for their common association with ferritin. Apart from these associations, the models showed no significant interactions between the six divalent metals studied. Very mild anaemia (110{<=}Hb<120 g/L) did not seem to have any effect independent of low ferritin. Approximately 26% of the women with iron deficiency anaemia had high concentrations of all of Mn, Co and Cd as opposed to 2.3% of iron-replete subjects. The results confirm that low serum ferritin may have an impact on body kinetics of certain divalent metal ions, but not all. Only a fraction of women with low iron status exhibited an increased blood concentration of divalent metals, providing indication of complexities in the body's handling of these metals.

  3. Characterization and identification of the sources of chromium, zinc, lead, cadmium, nickel, manganese and iron in PM10 particulates at the two sites of Kolkata, India.

    PubMed

    Karar, Kakoli; Gupta, A K; Kumar, Animesh; Biswas, Arun Kanti

    2006-09-01

    Monitoring of ambient PM10 (particulate matter which passes through a size selective impactor inlet with a 50% efficiency cut-off at 10 microm aerodynamic diameter) has been done at residential (Kasba) and industrial (Cossipore) sites of an urban region of Kolkata during November 2003 to November 2004. These sites were selected depending on the dominant anthropogenic activities. Metal constituents of atmospheric PM10 deposited on glass fibre filter paper were estimated using Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). Chromium (Cr), zinc (Zn), lead (Pb), cadmium (Cd), nickel (Ni), manganese (Mn) and iron (Fe) are the seven toxic trace metals quantified from the measured PM10 concentrations. The 24 h average concentrations of Cr, Zn, Pb, Cd, Ni, Mn and Fe from ninety PM10 particulate samples of Kolkata were found to be 6.9, 506.1, 79.1, 3.3, 7.4, 2.4 and 103.6 ng/m3, respectively. The 24 h average PM10 concentration exceeded national ambient air quality standard (NAAQS) as specified by central pollution control board, India at both residential (Kasba) and industrial (Cossipore) areas with mean concentration of 140.1 and 196.6 microg/m3, respectively. A simultaneous meteorology study was performed to assess the influence of air masses by wind speed, wind direction, rainfall, relative humidity and temperature. The measured toxic trace metals generally showed inverse relationship with wind speed, relative humidity and temperature. Factor analysis, a receptor modeling technique has been used for identification of the possible sources contributing to the PM10. Varimax rotated factor analysis identified four possible sources of measured trace metals comprising solid waste dumping, vehicular traffic with the influence of road dust, road dust and soil dust at residential site (Kasba), while vehicular traffic with the influence of soil dust, road dust, galvanizing and electroplating industry, and tanning industry at industrial site (Cossipore).

  4. Alterations in the metabolism of endogenous trace metals due to cadmium, manganese and nickel - effect of partial hepatectomy

    SciTech Connect

    Srivastava, R.C.; Ahmad, I.; Kaur, G.; Hasan, S.K.

    1988-01-01

    The effect of cadmium, manganese and nickel on the levels of copper, manganese, iron and zinc in liver was studied in sham operated and partially hepatectomized rats, 72 hrs after metal administration. Partial hepatectomy produced significant increase in the level of zinc and decrease in the levels of copper, iron and manganese. The metabolic disposition of these essential micronutrients were significantly altered as a result of cadmium administration in both the groups. Manganese and nickel had little effect and only induced the level of zinc.

  5. Lead, cadmium, iron, zinc, copper, manganese, calcium and magnesium in SPF male rats exposed to a dilution of automotive exhaust gas throughout their lives.

    PubMed

    Stupfel, M; Valleron, A J; Radford, E

    1983-12-15

    Male pathogen free CFE albino Sprague Dawley rats were exposed 8 h per day, 5 days per week, for three years to a 1/1000 dilution of automotive exhaust gas, containing 58 ppm carbon monoxide, 0.37% carbon dioxide, 23 ppm nitrogen oxides, 2 ppm aldehydes, less than 5 mg/l hydrocarbons and 8.5 micrograms/m3 lead. Lead, cadmium, iron, zinc, calcium and magnesium were measured by atomic absorption in the femurs and tibias of the rats which died during the experiment. A comparison with two control groups revealed that the only significant difference in the elements measured in the bones was a 500% increase in lead concentration. The calculations of the correlations between the percentages of the elements in bones, the ages and the body weights of the rats, as well as cluster analysis, did not show consistent variations of the water, calcium, magnesium concentrations nor of the other studied metals related to this increase in lead concentration. Moreover, longevity was the same in the 3 groups of rats, but the body weight was statistically smaller (4%) in the group exposed to the auto exhaust dilution.

  6. First principle study of manganese doped cadmium sulphide sheet

    SciTech Connect

    Kumar, Sanjeev; Kumar, Ashok; Ahluwalia, P. K.

    2014-04-24

    First-principle electronic structure calculations for cadmium sulphide (CdS) sheet in hexagonal phase, with Manganese substitution and addition, as well as including the Cd defects, are investigated. The lattice constants calculated for CdS sheet agrees fairly well with results reported for thin films experimentally. The calculations of total spin density of states and partial density of states in different cases shows substantial magnetic dipole moments acquired by the sheet. A magnetic dipole moment 5.00612 μ{sub B} and band gap of the order 1 eV are found when cadmium atom is replaced by Manganese. The magnetism acquired by the sheet makes it functionally important candidate in many applications.

  7. First principle study of manganese doped cadmium sulphide sheet

    NASA Astrophysics Data System (ADS)

    Kumar, Sanjeev; Kumar, Ashok; Ahluwalia, P. K.

    2014-04-01

    First-principle electronic structure calculations for cadmium sulphide (CdS) sheet in hexagonal phase, with Manganese substitution and addition, as well as including the Cd defects, are investigated. The lattice constants calculated for CdS sheet agrees fairly well with results reported for thin films experimentally. The calculations of total spin density of states and partial density of states in different cases shows substantial magnetic dipole moments acquired by the sheet. A magnetic dipole moment 5.00612 μB and band gap of the order 1 eV are found when cadmium atom is replaced by Manganese. The magnetism acquired by the sheet makes it functionally important candidate in many applications.

  8. Structural and mechanical studies of cadmium manganese thiocyanate crystal

    NASA Astrophysics Data System (ADS)

    Manikandan, M. R.; Vijayaprasath, G.; babu, G. Anandha; Bhagavannarayan, G.; Vijayan, N.; Ravi, G.

    2012-06-01

    Single crystals of cadmium manganese thiocyanate (CMTC) have been synthesized successfully and grown by slow evaporation method. The structural perfection of the grown crystals has been analyzed by High resolution X-ray diffraction (HRXRD), which shows the crystalline perfection of the grown crystal is quite good. Optical behavior was assessed by UV-Vis analysis and found that no absorption in the UV visible region and it may be useful for second harmonic applications. The mechanical hardness of the grown crystals was studied and Vicker's microhardness, Stiffness constant was calculated.

  9. Blood metal concentrations of manganese, lead, and cadmium in relation to serum ferritin levels in Ohio residents.

    PubMed

    Kim, Yangho; Lobdell, Danelle T; Wright, Chris W; Gocheva, Vihra V; Hudgens, Edward; Bowler, Rosemarie M

    2015-05-01

    The objectives of this study were to assess ferritin-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. Recruited participants included residents from Marietta, East Liverpool, and Mt. Vernon, OH, USA, who were aged 30-75 years and lived at least 10 years in their respective town. The levels of the neurotoxic metals such as manganese, cadmium, and lead were assayed in whole blood. Serum was analyzed for ferritin level [as a biomarker of iron (Fe) status]. An association between blood metal concentrations and independent variables (age, serum ferritin, manganese exposure status, and sex) by multiple regression analysis was assessed, controlling for various covariates such as BMI, educational level, smoking, and alcohol drinking status. Overall, the geometric means of blood manganese, cadmium, and lead levels of all participants (n = 276) were 9.307 μg/L, 0.393 μg/L, and 1.276 μg/dL, respectively. Log serum ferritin concentrations were inversely associated with log blood manganese concentration (β = -0.061 log ferritin and β = 0.146 categorical ferritin) and log blood cadmium concentrations (β = -0.090 log ferritin and β = 0.256 categorical ferritin). Log serum ferritin concentrations were not associated with log blood lead concentrations. Variables of age, sex, and exposure status were not associated with log manganese concentrations; however, log blood cadmium concentrations were higher in older population, women, and smokers. Log blood lead concentrations were higher in older population, men, and postmenopausal women. Our study showed that iron deficiency is associated with increased levels of blood manganese and cadmium, but not blood lead, in Ohio residents. These metals showed different toxicokinetics in relation to age, sex, and menopausal status despite

  10. Metabolism of manganese, iron, copper, and selenium in calves

    SciTech Connect

    Ho, S.Y.

    1981-01-01

    Sixteen male Holstein calves were used to study manganese and iron metabolism. The calves were fed one of the following diets for 18 days: control, control + iron, control + manganese, and control + iron and manganese. All calves were dosed orally with manganese-54. Tissue concentrations of manganese, iron and manganese-54 were determined. Small intestinal iron was lower in calves fed the high manganese diet than in controls. Tissue manganese-54 was lower in calves fed a high manganese diet. Fecal manganese content increased in calves fed both high manganese and high manganese-high iron diets. Serum total iron was not affected by the dietary treatments. To study the effects of high dietary levels of copper and selenium on the intracellular distributions of these two elements in liver and kidney cytosol, calves were fed one of four diets for 15 days. These were 0 and 100 ppM supplemental copper and 0 and 1 ppM added selenium. The control diet containing 0.1 ppM of selenium and 15 ppM of copper. All calves were orally dosed 48 hrs prior to sacrifice with selenium-75. A high copper diet increased copper concentrations in all intracellular liver fractions and most kidney fractions. Only the effects in the liver were significant. Less copper was found in the mitochondria fractions in liver and kidney of calves fed a high selenium diet. Three major copper-binding protein peaks were separated from the soluble fractions of calf liver and kidney. Peak 1 appeared to be the major copper-binding protein in liver and kidney cytosol of copper-loaded animals. Added selenium alone or in combination with copper accentuated the copper accumulation in this peak. Most of selenium-75 was recovered in the same peak as the copper. The results of this experiment indicated that the large molecular proteins in liver and kidney cytosol of calves play an important role in copper and selenium-75 metabolism. (ERB)

  11. Ferromagnetic properties of manganese doped iron silicide

    NASA Astrophysics Data System (ADS)

    Ruiz-Reyes, Angel; Fonseca, Luis F.; Sabirianov, Renat

    We report the synthesis of high quality Iron silicide (FeSi) nanowires via Chemical Vapor Deposition (CVD). The materials exhibits excellent magnetic response at room temperature, especially when doped with manganese showing values of 2.0 X 10-04 emu for the FexMnySi nanowires. SEM and TEM characterization indicates that the synthesized nanowires have a diameter of approximately 80nm. MFM measurements present a clear description of the magnetic domains when the nanowires are doped with manganese. Electron Diffraction and XRD measurements confirms that the nanowires are single crystal forming a simple cubic structure with space group P213. First-principle calculations were performed on (111) FeSi surface using the Vienna ab initio simulation package (VASP). The exchange correlations were treated under the Ceperley-Alder (CA) local density approximation (LDA). The Brillouin Zone was sampled with 8x8x1 k-point grid. A total magnetic moment of about 10 μB was obtained for three different surface configuration in which the Iron atom nearest to the surface present the higher magnetization. To study the effect of Mn doping, Fe atom was replaced for a Mn. Stronger magnetization is presented when the Mn atom is close to the surface. The exchange coupling constant have been evaluated calculating the energy difference between the ferromagnetic and anti-ferromagnetic configurations.

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

    SciTech Connect

    Rousselet, Estelle |; Richaud, Pierre ||; Douki, Thierry; Chantegrel, Jocelyne Garcia; Favier, Alain |||; Moulis, Jean-Marc ||

    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.

  13. 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.

  14. 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.

  15. 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...

  16. Iron and manganese oxide mineralization in the Pacific

    USGS Publications Warehouse

    Hein, J. R.; Koschinsky, A.; Halbach, P.; Manheim, F. T.; Bau, M.; Jung-Keuk, Kang; Lubick, N.

    1997-01-01

    Iron, manganese, and iron-manganese deposits occur in nearly all geomorphologic and tectonic environments in the ocean basins and form by one or more of four processes: (1) hydrogenetic precipitation from cold ambient seawater, (2) precipitation from hydrothermal fluids, (3) precipitation from sediment pore waters that have been modified from bottom water compositions by diagenetic reactions in the sediment column and (4) replacement of rocks and sediment. These processes are discussed.

  17. The Interaction of Mitochondrial Iron with Manganese Superoxide Dismutase*

    PubMed Central

    Naranuntarat, Amornrat; Jensen, Laran T.; Pazicni, Samuel; Penner-Hahn, James E.; Culotta, Valeria C.

    2009-01-01

    Superoxide dismutase 2 (SOD2) is one of the rare mitochondrial enzymes evolved to use manganese as a cofactor over the more abundant element iron. Although mitochondrial iron does not normally bind SOD2, iron will misincorporate into Saccharomyces cerevisiae Sod2p when cells are starved for manganese or when mitochondrial iron homeostasis is disrupted by mutations in yeast grx5, ssq1, and mtm1. We report here that such changes in mitochondrial manganese and iron similarly affect cofactor selection in a heterologously expressed Escherichia coli Mn-SOD, but not a highly homologous Fe-SOD. By x-ray absorption near edge structure and extended x-ray absorption fine structure analyses of isolated mitochondria, we find that misincorporation of iron into yeast Sod2p does not correlate with significant changes in the average oxidation state or coordination chemistry of bulk mitochondrial iron. Instead, small changes in mitochondrial iron are likely to promote iron-SOD2 interactions. Iron binds Sod2p in yeast mutants blocking late stages of iron-sulfur cluster biogenesis (grx5, ssq1, and atm1), but not in mutants defective in the upstream Isu proteins that serve as scaffolds for iron-sulfur biosynthesis. In fact, we observed a requirement for the Isu proteins in iron inactivation of yeast Sod2p. Sod2p activity was restored in mtm1 and grx5 mutants by depleting cells of Isu proteins or using a dominant negative Isu1p predicted to stabilize iron binding to Isu1p. In all cases where disruptions in iron homeostasis inactivated Sod2p, we observed an increase in mitochondrial Isu proteins. These studies indicate that the Isu proteins and the iron-sulfur pathway can donate iron to Sod2p. PMID:19561359

  18. Manganese- and iron-dependent marine methane oxidation.

    PubMed

    Beal, Emily J; House, Christopher H; Orphan, Victoria J

    2009-07-10

    Anaerobic methanotrophs help regulate Earth's climate and may have been an important part of the microbial ecosystem on the early Earth. The anaerobic oxidation of methane (AOM) is often thought of as a sulfate-dependent process, despite the fact that other electron acceptors are more energetically favorable. Here, we show that microorganisms from marine methane-seep sediment in the Eel River Basin in California are capable of using manganese (birnessite) and iron (ferrihydrite) to oxidize methane, revealing that marine AOM is coupled, either directly or indirectly, to a larger variety of oxidants than previously thought. Large amounts of manganese and iron are provided to oceans from rivers, indicating that manganese- and iron-dependent AOM have the potential to be globally important.

  19. 40 CFR 721.10529 - Cobalt iron manganese oxide, carboxylic acid-modified (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Cobalt iron manganese oxide... Significant New Uses for Specific Chemical Substances § 721.10529 Cobalt iron manganese oxide, carboxylic acid... substance identified generically as cobalt iron manganese oxide, carboxylic acid-modified (PMN P-12-35)...

  20. 40 CFR 721.10529 - Cobalt iron manganese oxide, carboxylic acid-modified (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Cobalt iron manganese oxide... Significant New Uses for Specific Chemical Substances § 721.10529 Cobalt iron manganese oxide, carboxylic acid... substance identified generically as cobalt iron manganese oxide, carboxylic acid-modified (PMN P-12-35)...

  1. Solubilisation effect of spent wash on oxide-ores of manganese and iron.

    PubMed

    Pervez, S; Pandey, G S

    1991-09-01

    Samples of iron ore (haematite) and manganese ore (pyrolusite) of known compositions were equilibrated with aliquots of analysed sample of spent wash. The concentrations of iron(II), iron(III), complexed iron, manganese(II) ions and complexed Mn-ions were determined after increasing durations. One litre of the spent wash was found to extract out 141 mg of total iron and 161 mg of total manganese. In case of iron, the predominance was of iron(II) (92%), whereas in case of manganese it was of the complexed form (95%).

  2. Interactions of manganese, iron, and copper in healthy human subjects

    SciTech Connect

    Lin, Paohwa.

    1989-01-01

    In study I, plasma levels of manganese and iron were measured after an oral load was ingested. Four hourly samples of plasma were collected postdose. The ingestion of a dose of 40 mg Mn alone produced a typical response in plasma manganese, which peaked at either the first or second hour postdose. When a combined dose of 40 mg inorganic Fe plus 40 mg Mn was given, the plasma uptake of manganese was substantially inhibited when compared to a dose of 40 mg Mn alone. When the same quantity of heme Fe was substituted for the inorganic Fe in the load of inorganic Fe plus Mn, no depression in plasma manganese was observed. In study II, eight healthy female subjects were fed a baseline Mn-adequate diet of conventional foods for 18 days, followed by a Mn-deficient semi-purified diet for 41 days. Dietary levels of iron and copper averaged 17.7 mg and 4.3 mg/day, respectively, for both diets. Mean iron balance increased significantly from initial levels of 2.20 {plus minus} 1.07 mg/d to 5.02 {plus minus} 1.14 mg/d at the end of the Mn-deficient period. Parameters of iron status were not influenced by the variations of dietary manganese. In contrast, mean copper balance decreased from 2.61 {plus minus} 0.1 mg/d to 0.91 {plus minus} 0.4 mg/d at the end of the Mn-deficient period. Correspondingly, plasma copper and serum ceruloplasmin decreased from 18.57 {plus minus} 1.1 {mu}mol/L to 15.27 {plus minus} 0.94 {mu}mol/L and 269.1 {plus minus} 14.6 mg/L to 205.6 {plus minus} 17.8 mg/L., respectively.

  3. Heavy metal pollution among autoworkers. II. Cadmium, chromium, copper, manganese, and nickel.

    PubMed Central

    Clausen, J; Rastogi, S C

    1977-01-01

    Garages and auto-repair workshops may be polluted with other heavy metals besides lead. Blood of autoworkers with high lead content was analysed for cadmium, chromium, copper manganese, nickel, ALAD activity and carboxyhaemoglobin level. Cadmium and copper levels in blood of autoworkers were comparable with those of the control subjects while chroimium and nickel levels were significantly higher (P less than 0-01 for both metals), and scattered raised values of manganese were found. There was no significant mutual correlation between levels of various heavy metals determined in whole blood. High copper levels were slightly related to decreasing ALAD activity (P less than 0-1). Nineteen per cent of autoworkers were found to have an abnormally blood level of carboxyhaemoglobin. The amount of particulate heavy metal in autoworkshop air was not related to biochemical abnormalities found in the autoworkers. Various sources of pollution of these heavy metals in autoworkshops are discussed. PMID:71915

  4. Iron and manganese oxide mineralization in the Pacific

    USGS Publications Warehouse

    Hein, J.R.; Koschinsky, A.; Halbach, P.; Manheim, F. T.; Bau, M.; Kang, J.-K.; Lubick, N.

    1997-01-01

    Iron, manganese, and iron-manganese deposits occur in nearly all geomorphologic and tectonic environments in the ocean basins and form by one or more of four processes: (1) hydrogenetic precipitation from cold ambient seawater, (2) precipitation from hydrothermal fluids, (3) precipitation from sediment pore waters that have been modified from bottom water compositions by diagenetic reactions in the sediment column and (4) replacement of rocks and sediment. Iron and manganese deposits occur in five forms: nodules, crusts, cements, mounds and sediment-hosted stratabound layers. Seafloor oxides show a wide range of compositions from nearly pure iron to nearly pure manganese end members. Fe/Mn ratios vary from about 24 000 (up to 58% elemental Fe) for hydrothermal seamount ironstones to about 0.001 (up to 52% Mn) for hydrothermal stratabound manganese oxides from active volcanic arcs. Hydrogenetic Fe-Mn crusts that occur on most seamounts in the ocean basins have a mean Fe/Mn ratio of 0.7 for open-ocean seamount crusts and 1.2 for continental margin seamount crusts. Fe-Mn nodules of potential economic interest from the Clarion-Clipperton Zone have a mean Fe/Mn ratio of 0.3, whereas the mean ratio for nodules from elsewhere in the Pacific is about 0.7. Crusts are enriched in Co, Ni and Pt and nodules in Cu and Ni, and both have significant concentrations of Pb, Zn, Ba, Mo, V and other elements. In contrast, hydrothermal deposits commonly contain only minor trace metal contents, although there are many exceptions, for example, with Ni contents up to 0.66%, Cr to 1.2%, and Zn to 1.4%. Chondrite-normalized REE patterns generally show a positive Ce anomaly and abundant ??REEs for hydrogenetic and mixed hydrogenetic-diagenetic deposits, whereas the Ce anomaly is negative for hydrothermal deposits and ??REE contents are low. However, the Ce anomaly in crusts may vary from strongly positive in East Pacific crusts to slightly negative in West Pacific crusts, which may reflect

  5. Iron isotopes constrain biogeochemical redox cycling of iron and manganese in a Palaeoproterozoic stratified basin

    NASA Astrophysics Data System (ADS)

    Tsikos, Harilaos; Matthews, Alan; Erel, Yigal; Moore, John M.

    2010-09-01

    The Hotazel Formation in the uppermost stratigraphic portion of the Neoarchaean-Palaeoproterozoic Transvaal Supergroup of southern Africa is an unusual sedimentary sequence of banded iron-formation (BIF) intercalated with three manganese-rich layers. As such, it is a succession that holds great potential to offer a unique view of one of the most dramatic transitions in early Earth history — the switch to a full oxidative cycle in shallow oceans at ca. 2.3 Ga. We present iron isotope results from BIF and Mn-rich samples collected across the entire Hotazel sequence, with a view to constraining processes of biogeochemical redox cycling for both metals close to the transition from a reducing to an oxidizing ocean-atmosphere system. The recorded de-coupling of Fe- and Mn reduction during anaerobic organic carbon cycling in the Hotazel strata, suggests that manganese became an important electron acceptor in stratified marine environments of the Palaeoproterozoic during periods of increased primary manganese precipitation relative to iron. Very low δ 57Fe values registered across the entire Hotazel sequence and especially in manganese-rich samples (-2.4 to -3.5‰) signify deposition of iron and manganese in a terminal, stratified aqueous reservoir that was depleted in the heavy iron isotopes. These isotopic signatures, in conjunction with the unusual endowment of the Hotazel sequence in manganese, are interpreted to have evolved by Rayleigh distillation processes during protracted deposition of Mn-poor BIFs as preserved in the lower stratigraphic portion of the Transvaal Supergroup (Kuruman and Griquatown BIFs). The unique end-member geochemical and isotopic characteristics of the Hotazel rocks may therefore constitute a potential link between the widespread deposition of BIF during the Neoarchaean and Palaeoproterozoic, and the postulated rise in atmospheric oxygen levels around 2.3 Ga ago.

  6. Evaluation of the effect of divalent metal transporter 1 gene polymorphism on blood iron, lead and cadmium levels

    SciTech Connect

    Kayaaltı, Zeliha Akyüzlü, Dilek Kaya; Söylemezoğlu, Tülin

    2015-02-15

    Divalent metal transporter 1 (DMT1), a member of the proton-coupled metal ion transporter family, mediates transport of ferrous iron from the lumen of the intestine into the enterocyte and export of iron from endocytic vesicles. It has an affinity not only for iron but also for other divalent cations including manganese, cobalt, nickel, cadmium, lead, copper, and zinc. DMT1 is encoded by the SLC11a2 gene that is located on chromosome 12q13 in humans and express four major mammalian isoforms (1A/+IRE, 1A/-IRE, 2/+IRE and 2/-IRE). Mutations or polymorphisms of DMT1 gene may have an impact on human health by disturbing metal trafficking. To study the possible association of DMT1 gene with the blood levels of some divalent cations such as iron, lead and cadmium, a single nucleotide polymorphism (SNP) (IVS4+44C/A) in DMT1 gene was investigated in 486 unrelated and healthy individuals in a Turkish population by method of polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP). The genotype frequencies were found as 49.8% homozygote typical (CC), 38.3% heterozygote (CA) and 11.9% homozygote atypical (AA). Metal levels were analyzed by dual atomic absorption spectrometer system and the average levels of iron, lead and cadmium in the blood samples were 446.01±81.87 ppm, 35.59±17.72 ppb and 1.25±0.87 ppb, respectively. Individuals with the CC genotype had higher blood iron, lead and cadmium levels than those with AA and CA genotypes. Highly statistically significant associations were detected between IVS4+44 C/A polymorphism in the DMT1 gene and iron and lead levels (p=0.001 and p=0.036, respectively), but no association was found with cadmium level (p=0.344). This study suggested that DMT1 IVS4+44 C/A polymorphism is associated with inter-individual variations in blood iron, lead and cadmium levels. - Highlights: • DMT1 IVS4+44 C/A polymorphism is associated with inter-individual variations in blood iron, cadmium and lead levels.

  7. Zinc, iron, manganese, and magnesium accumulation in crayfish populations near copper-nickel smelters at Sudbury, Ontario, Canada

    SciTech Connect

    Bagatto, G.; Alikhan, M.A.

    1987-06-01

    The Sudbury basin has been subjected to extreme ecological disturbances from logging, mining and smelting activities. Elevated concentrations of copper, cadmium, and nickel have been reported in crayfish populations close to the Sudbury smelting works. The present study compares concentrations of zinc (Zn), iron (Fe), manganese (Mn) and magnesium (Mg) in freshwater crayfish at selected distances of the habitat from the emission source. These metals were selected since they are known to be emitted in moderately high quantities into the Sudbury environment as byproduct of the smelting process. Various tissue concentrations in crayfish were also examined to determined specific tissue sites for these accumulations.

  8. Use of potassium permanganate for iron and manganese removal from acid mine drainage

    SciTech Connect

    Boll, J.E.; Deshinsky, G.

    1985-12-09

    Surface and deep shaft coal mining operations find it difficult to meet Environmental Protection Agency (EPA) standards concerning acid, iron and manganese in drainage waters. Correcting the acid and iron problem is relatively simple, but effectively controlling manganese is more difficult. The best way to remove manganese is by chemical oxidation. A common treatment method is pH adjustment with lime or soda ash. This practice neutralizes the acid and removes most of the iron by forming an insoluble precipitate. The amount of lime or soda ash needed to remove manganese raises the pH beyond the acceptable range of 6-9. Potassium permanganate (KMnO/sub 4/) can be used to oxidize the dissolved manganese to an insoluble manganese precipitate. It can also oxidize any residual iron. The adjusted pH reduces unnecessary consumption of permanganate needed to oxidize manganese and meets EPA standards. It reacts on contact producing an insoluble manganese dioxide (MnO/sub 2/). The MnO/sub 2/ supplements the oxidation with a settling effect. Permanganate can be applied at all pHs, with faster results at neutral or slightly alkaline levels. Its use for iron and manganese removal is very attractive because the reactions are complete, rapid, and require only a minimal amount of chemicals. Laboratory evaluation and field case histories will be discussed in the paper. 3 figures.

  9. 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.

  10. Removal of cadmium, zinc, manganese and chromium cations from aqueous solution by a clay mineral.

    PubMed

    da Fonseca, Maria G; de Oliveira, Michelle M; Arakaki, Luiza N H

    2006-09-01

    Vermiculite, a 2:1 clay mineral, was applied as adsorbent for removal of cadmium, zinc, manganese, and chromium from aqueous solutions. Parameters such as time of reaction, effect of pH and cation concentration were investigated. All isotherms were L type of the Gilles classification, except zinc (type S). The adsorbent showed good sorption potential for these cations. The experimental data was analyzed by Langmuir isotherm model showing reasonable adjustment. The quantity of adsorbed cations was 0.50, 0.52, 0.60, and 0.48 mmol g(-1) of Cd(2+), Mn(2+), Zn(2+), and Cr(3+), respectively.

  11. Distribution of Cadmium, Iron, and Zinc in Millstreams of Hard Winter Wheat (Triticum aestivum L.).

    PubMed

    Guttieri, Mary J; Seabourn, Bradford W; Liu, Caixia; Baenziger, P Stephen; Waters, Brian M

    2015-12-16

    Hard winter wheat (Triticum aestivum L.) is a major crop in the Great Plains of the United States, and our previous work demonstrated that wheat genotypes vary for grain cadmium accumulation with some exceeding the CODEX standard (0.2 mg kg(-1)). Previous reports of cadmium distribution in flour milling fractions have not included high cadmium grain. This study measured the distribution of cadmium, zinc, and iron in flour and bran streams from high cadmium (0.352 mg kg(-1)) grain on a pilot mill that produced 12 flour and four bran streams. Recovery in flour was substantially greater for cadmium (50%) than for zinc (31%) or iron (22%). Cadmium, zinc, and iron in the lowest mineral concentration flour stream, representing the purest endosperm fraction, were 52, 22, and 11%, respectively, of initial grain concentration. Our results indicate that, relative to zinc and iron, a greater proportion of cadmium is stored in the endosperm, the source of white flour.

  12. Stress response to cadmium and manganese in Paracentrotus lividus developing embryos is mediated by nitric oxide.

    PubMed

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

    2014-11-01

    Increasing concentrations of contaminants, often resulting from anthropogenic activities, have been reported to occur in the marine environment and affect marine organisms. Among these, the metal ions cadmium and manganese have been shown to induce developmental delay and abnormalities, mainly reflecting skeleton elongation perturbation, in the sea urchin Paracentrotus lividus, an established model for toxicological studies. Here, we provide evidence that the physiological messenger nitric oxide (NO), formed by l-arginine oxidation by NO synthase (NOS), mediates the stress response induced by cadmium and manganese in sea urchins. When NO levels were lowered by inhibiting NOS, the proportion of abnormal plutei increased. Quantitative expression of a panel of 19 genes involved in stress response, skeletogenesis, detoxification and multidrug efflux processes was followed at different developmental stages and under different conditions: metals alone, metals in the presence of NOS inhibitor, NO donor and NOS inhibitor alone. These data allowed the identification of different classes of genes whose metal-induced transcriptional expression was directly or indirectly mediated by NO. These results open new perspectives on the role of NO as a sensor of different stress agents in sea urchin developing embryos.

  13. Characterization of iron and manganese precipitates from an in situ ground water treatment plant.

    PubMed

    Mettler, S; Abdelmoula, M; Hoehn, E; Schoenenberger, R; Weidler, P; von Gunten, U

    2001-01-01

    Aquifer samples from the precipitation zone of an in situ iron and manganese removal plant that was operated for 10 years were analyzed for iron and manganese minerals. Measurements were performed by various chemical extraction techniques (5 M HCI, 0.008 M Ti(III)-EDTA, 0.114 M ascorbic acid), X-ray diffraction and Mössbauer spectroscopy. Chemical extractions showed that iron was precipitated as ferric oxides, whereas manganese was not oxidized but deposited as Mn(II) probably within carbonates. The ferric oxides in particular accumulate preferentially in the smaller grain- size fractions. This tendency was observed to a lesser extent for manganese. X-ray diffraction and Mössbauer spectroscopy showed that the ferric oxides were mainly crystalline (goethite, 50% to 100% of the iron). Ferrihydrite was found as well, but only as a minor fraction (< or = 12%). Pure manganese minerals were not found by X-ray diffraction. The precipitated amounts of iron (5 to 27 micromol/g Fe as ferric oxide) and manganese (1 to 4 micromol/g Mn) during 10 years operation of the treatment plant agree with values that were estimated from operational parameters (9 to 31 micromol/g Fe and 3 to 6 micromol/g Mn). Considering the small amounts of precipitated iron and manganese, no long-term risks of clogging of the aquifer are expected.

  14. Formation of Defected Cadmium Ferrite during Hydrothermal Storage of Cadmium-Iron Hydroxides

    NASA Astrophysics Data System (ADS)

    Wolski, W.; Wolska, E.; Kaczmarek, J.

    1994-05-01

    The storage of amorphous coprecipitated Cd(OH) 2 · 2Fe(OH) 3 gel in mother liquor at 150 ± 2°C for 20 hr leads to a crystalline species which, according to X-ray analysis, is composed of cadmium hydroxide nitrate, Cd 3(OH) 5NO 3, cadmium hydroxide, βCd(OH) 2, and a strongly ferrimagnetic spinel phase. The Curie point at 270-280°C was found by thermomagnetic analysis. At that temperature the decomposition of the spinel phase and of the accompanying nonmagnetic phases takes place. IR spectra indicate that during thermomagnetic recording the liberated cadmium oxide and iron oxide form antiferromagnetic cadmium ferrite, with frequencies somewhat displaced in comparison to CdFe 2O 4 annealed at 1000°C. The results indicate that the ferrimagnetic phase (having spinel structure, a unit-cell parameter a of about 8.37 ± 0.01 Å, and a Tc point differing by more than 300°C from that of pure maghemite, γFe 2O 3) is likely to be a defected solid solution of maghemite and cadmium ferrite, of the formula Cd 2+xFe 3+1- x [Fe 3+(5+ x)/3 □ (1- x)/3 ]O 4.

  15. Evaluation of the effect of divalent metal transporter 1 gene polymorphism on blood iron, lead and cadmium levels.

    PubMed

    Kayaaltı, Zeliha; Akyüzlü, Dilek Kaya; Söylemezoğlu, Tülin

    2015-02-01

    Divalent metal transporter 1 (DMT1), a member of the proton-coupled metal ion transporter family, mediates transport of ferrous iron from the lumen of the intestine into the enterocyte and export of iron from endocytic vesicles. It has an affinity not only for iron but also for other divalent cations including manganese, cobalt, nickel, cadmium, lead, copper, and zinc. DMT1 is encoded by the SLC11a2 gene that is located on chromosome 12q13 in humans and express four major mammalian isoforms (1A/+IRE, 1A/-IRE, 2/+IRE and 2/-IRE). Mutations or polymorphisms of DMT1 gene may have an impact on human health by disturbing metal trafficking. To study the possible association of DMT1 gene with the blood levels of some divalent cations such as iron, lead and cadmium, a single nucleotide polymorphism (SNP) (IVS4+44C/A) in DMT1 gene was investigated in 486 unrelated and healthy individuals in a Turkish population by method of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The genotype frequencies were found as 49.8% homozygote typical (CC), 38.3% heterozygote (CA) and 11.9% homozygote atypical (AA). Metal levels were analyzed by dual atomic absorption spectrometer system and the average levels of iron, lead and cadmium in the blood samples were 446.01 ± 81.87 ppm, 35.59 ± 17.72 ppb and 1.25 ± 0.87 ppb, respectively. Individuals with the CC genotype had higher blood iron, lead and cadmium levels than those with AA and CA genotypes. Highly statistically significant associations were detected between IVS4+44 C/A polymorphism in the DMT1 gene and iron and lead levels (p=0.001 and p=0.036, respectively), but no association was found with cadmium level (p=0.344). This study suggested that DMT1 IVS4+44 C/A polymorphism is associated with inter-individual variations in blood iron, lead and cadmium levels.

  16. 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....

  17. Tissue distribution of manganese in iron-sufficient or iron-deficient rats after stainless steel welding-fume exposure.

    PubMed

    Park, Jung-Duck; Kim, Ki-Young; Kim, Dong-Won; Choi, Seong-Jin; Choi, Byung-Sun; Chung, Yong Hyun; Han, Jeong Hee; Sung, Jae Hyuck; Kwon, Il Hoon; Mun, Je-Hyeok; Yu, Il Je

    2007-05-01

    Welders can be exposed to high levels of manganese through welding fumes. Although it has already been suggested that excessive manganese exposure causes neurotoxicity, called manganism, the pathway of manganese transport to the brain with welding-fume exposure remains unclear. Iron is an essential metal that maintains a homeostasis in the body. The divalent metal transporter 1 (DMT1) transports iron and other divalent metals, such as manganese, and the depletion of iron is known to upregulate DMT1 expression. Accordingly, this study investigated the tissue distribution of manganese in iron-sufficient and iron-deficient rats after welding-fume exposure. The feeding of an iron-deficient diet for 4 wk produced a depletion of body iron, such as decreased iron levels in the serum and tissues, and upregulated the DMT1 expression in the rat duodenum. The iron-sufficient and iron-deficient rats were then exposed to welding fumes generated from manual metal arc stainless steel at a concentration of 63.5 +/- 2.3 mg/m3 for 2 h per day over a 30-day period. Animals were sacrificed on days 1, 15, and 30. The level of body iron in the iron-deficient rats was restored to the control level after the welding-fume exposure. However, the tissue distributions of manganese after the welding-fume exposure showed similar patterns in both the iron-sufficient and iron-deficient groups. The concentration of manganese increased in the lungs and liver on days 15 and 30, and increased in the olfactory bulb on day 30. Slight and heterogeneous increases of manganese were observed in different brain regions. Consequently, these findings suggest that the presence of Fe in the inhaled welding fumes may not have a significant effect on the uptake of Mn into the brain. Thus, the condition of iron deficiency did not seem to have any apparent effect on the transport of Mn into the brain after the inhalation of welding fumes.

  18. Hawaiian submarine manganese-iron oxide crusts - A dating tool?

    USGS Publications Warehouse

    Moore, J.G.; Clague, D.A.

    2004-01-01

    Black manganese-iron oxide crusts form on most exposed rock on the ocean floor. Such crusts are well developed on the steep lava slopes of the Hawaiian Ridge and have been sampled during dredging and submersible dives. The crusts also occur on fragments detached from bedrock by mass wasting, on submerged coral reefs, and on poorly lithified sedimentary rocks. The thickness of the crusts was measured on samples collected since 1965 on the Hawaiian Ridge from 140 dive or dredge localities. Fifty-nine (42%) of the sites were collected in 2001 by remotely operated vehicles (ROVs). The thinner crusts on many samples apparently result from post-depositional breakage, landsliding, and intermittent burial of outcrops by sediment. The maximum crust thickness was selected from each dredge or dive site to best represent crusts on the original rock surface at that site. The measurements show an irregular progressive thickening of the crusts toward the northwest-i.e., progressive thickening toward the older volcanic features with increasing distance from the Hawaiian hotspot. Comparison of the maximum crust thickness with radiometric ages of related subaerial features supports previous studies that indicate a crust-growth rate of about 2.5 mm/m.y. The thickness information not only allows a comparison of the relative exposure ages of two or more features offshore from different volcanoes, but also provides specific age estimates of volcanic and landslide deposits. The data indicate that some of the landslide blocks within the south Kona landslide are the oldest exposed rock on Mauna Loa, Kilauea, or Loihi volcanoes. Crusts on the floors of submarine canyons off Kohala and East Molokai volcanoes indicate that these canyons are no longer serving as channelways for downslope, sediment-laden currents. Mahukona volcano was approximately synchronous with Hilo Ridge, both being younger than Hana Ridge. The Nuuanu landslide is considerably older than the Wailau landslide. The Waianae

  19. Interactions between excessive manganese exposures and dietary iron-deficiency in neurodegeneration.

    PubMed

    Erikson, Keith M; Syversen, Tore; Aschner, Judy L; Aschner, Michael

    2005-05-01

    For nearly a century, manganese has been recognized as an essential nutrient for proper bone formation, lipid, amino acid and carbohydrate metabolism. While manganese deficiency is characterized by symptoms ranging from stunted growth and poor bone remodeling to ataxia, it is manganese toxicity that is far more devastating from a public health standpoint. Most cases of manganese toxicity are the result of occupational exposure to high levels of the metal, and are characterized by specific neurological symptoms referred to as manganism. While manganism shares many common features with Parkinson's disease, there are distinct differences between the two disorders suggesting that manganism might indirectly affect nigrostriatal dopaminergic function. Recent studies from our laboratory show that dietary iron deficiency is a risk factor for brain manganese accumulation and that the striatum is particularly vulnerable. This review briefly discusses manganese from nutritional and toxicological aspects.

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

    PubMed

    Chen, Chia-Chu; Whitaker, John F

    2010-06-07

    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.

  1. The influence of high iron diet on rat lung manganese absorption

    SciTech Connect

    Thompson, Khristy; Molina, Ramon; Donaghey, Thomas; Brain, Joseph D.; Wessling-Resnick, Marianne . E-mail: wessling@hsph.harvard.edu

    2006-01-15

    Individuals chronically exposed to manganese are at high risk for neurotoxic effects of this metal. A primary route of exposure is through respiration, although little is known about pulmonary uptake of metals or factors that modify this process. High dietary iron levels inversely affect intestinal uptake of manganese, and a major goal of this study was to determine if dietary iron loading could increase lung non-heme iron levels and alter manganese absorption. Rats were fed a high iron (1% carbonyl iron) or control diet for 4 weeks. Lung non-heme iron levels increased {approx}2-fold in rats fed the high iron diet. To determine if iron-loading affected manganese uptake, {sup 54}Mn was administered by intratracheal (it) instillation or intravenous (iv) injection for pharmacokinetic studies. {sup 54}Mn absorption from the lungs to the blood was lower in it-instilled rats fed the 1% carbonyl iron diet. Pharmacokinetics of iv-injected {sup 54}Mn revealed that the isotope was cleared more rapidly from the blood of iron-loaded rats. In situ analysis of divalent metal transporter-1 (DMT1) expression in lung detected mRNA in airway epithelium and bronchus-associated lymphatic tissue (BALT). Staining of the latter was significantly reduced in rats fed the high iron diet. In situ analysis of transferrin receptor (TfR) mRNA showed staining in BALT alone. These data demonstrate that manganese absorption from the lungs to the blood can be modified by iron status and the route of administration.

  2. 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.

  3. 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 μg/dL), 4.4 (2.4 μg/L), 10.9 (9.2 μg/L), and 43.7 (17.7 μg/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 μg/L vs. 6.4 μg/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

  4. Immobilization of iron- and manganese-oxidizing bacteria with a biofilm-forming bacterium for the effective removal of iron and manganese from groundwater.

    PubMed

    Li, Chunyan; Wang, Shuting; Du, Xiaopeng; Cheng, Xiaosong; Fu, Meng; Hou, Ning; Li, Dapeng

    2016-11-01

    In this study, three bacteria with high Fe- and Mn-oxidizing capabilities were isolated from groundwater well sludge and identified as Acinetobacter sp., Bacillus megaterium and Sphingobacterium sp. The maximum removal ratios of Fe and Mn (99.75% and 96.69%) were obtained by an optimal combination of the bacteria at a temperature of 20.15°C, pH 7.09 and an inoculum size of 2.08%. Four lab-scale biofilters were tested in parallel for the removal of iron and manganese ions from groundwater. The results indicated that the Fe/Mn removal ratios of biofilter R4, which was inoculated with iron- and manganese-oxidizing bacteria and a biofilm-forming bacterium, were approximately 95% for each metal during continuous operation and were better than the other biofilters. This study demonstrated that the biofilm-forming bacterium could promote the immobilization of the iron- and manganese-oxidizing bacteria on the biofilters and enhance the removal efficiency of iron and manganese ions from groundwater.

  5. 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 μM) 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.

  6. Influence of iron and zinc status on cadmium accumulation in Bangladeshi women

    SciTech Connect

    Kippler, Maria; Ekstroem, Eva-Charlotte; Loennerdal, Bo; Goessler, Walter; Akesson, Agneta; El Arifeen, Shams; Persson, Lars-Ake; Vahter, Marie . E-mail: Marie.Vahter@ki.se

    2007-07-15

    Cadmium is a widespread environmental contaminant present in food. The absorption in the intestine increases in individuals with low iron stores, but the effect of zinc deficiency is not clear. The aim of the present study was to assess the influence of iron and zinc status on cadmium accumulation in pregnant Bangladeshi women. We measured cadmium in urine from 890 women using inductively coupled plasma mass spectrometry (ICPMS). Further, we also measured ferritin and zinc in plasma. The median cadmium concentration in urine was 0.59 {mu}g/L (adjusted to mean specific gravity of 1.012 g/mL). Analysis of covariance (ANCOVA) showed that urinary cadmium was associated with plasma ferritin and plasma zinc via a significant interaction between dichotomized plasma ferritin and plasma zinc. The analysis was adjusted for age and socioeconomic status. Women with low iron stores and adequate zinc status had significantly higher urinary cadmium compared to women with both adequate iron stores and zinc status. There was no difference in urinary cadmium between women with both low iron stores and zinc status compared to those with both adequate iron stores and zinc status. In conclusion, low iron stores were associated with increased cadmium accumulation, but only at adequate zinc status.

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

    PubMed Central

    Yabuuchi, Naoaki; Komaba, Shinichi

    2014-01-01

    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. PMID:27877694

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

    PubMed

    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.

  9. 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.

  10. Multiple inorganic toxic substances contaminating the groundwater of Myingyan Township, Myanmar: arsenic, manganese, fluoride, iron, and uranium.

    PubMed

    Bacquart, Thomas; Frisbie, Seth; Mitchell, Erika; Grigg, Laurie; Cole, Christopher; Small, Colleen; Sarkar, Bibudhendra

    2015-06-01

    In South Asia, the technological and societal shift from drinking surface water to groundwater has resulted in a great reduction of acute diseases due to water borne pathogens. However, arsenic and other naturally occurring inorganic toxic substances present in groundwater in the region have been linked to a variety of chronic diseases, including cancers, heart disease, and neurological problems. Due to the highly specific symptoms of chronic arsenic poisoning, arsenic was the first inorganic toxic substance to be noticed at unsafe levels in the groundwater of West Bengal, India and Bangladesh. Subsequently, other inorganic toxic substances, including manganese, uranium, and fluoride have been found at unsafe levels in groundwater in South Asia. While numerous drinking water wells throughout Myanmar have been tested for arsenic, relatively little is known about the concentrations of other inorganic toxic substances in Myanmar groundwater. In this study, we analyzed samples from 18 drinking water wells (12 in Myingyan City and 6 in nearby Tha Pyay Thar Village) and 2 locations in the Ayeyarwaddy River for arsenic, boron, barium, beryllium, cadmium, cobalt, chromium, copper, fluoride, iron, mercury, manganese, molybdenum, nickel, lead, antimony, selenium, thallium, uranium, vanadium, and zinc. Concentrations of arsenic, manganese, fluoride, iron, or uranium exceeded health-based reference values in most wells. In addition, any given well usually contained more than one toxic substance at unsafe concentrations. While water testing and well sharing could reduce health risks, none of the wells sampled provide water that is entirely safe with respect to inorganic toxic substances. It is imperative that users of these wells, and users of other wells that have not been tested for multiple inorganic toxic substances throughout the region, be informed of the need for drinking water testing and the health consequences of drinking water contaminated with inorganic toxic

  11. The scavenging of silver by manganese and iron oxides in stream sediments collected from two drainage areas of Colorado

    USGS Publications Warehouse

    Chao, T.T.; Anderson, B.J.

    1974-01-01

    Stream sediments of two well-weathered and aerated drainage areas of Colorado containing anomalous amounts of silver were allowed to react by shaking with nitric acid of different concentrations (1-10M). Silver, manganese, and iron simultaneously dissolved were determined by atomic absorption. The relationship between silver dissolution and the dissolution of manganese and/or iron was evaluated by linear and multiple regression analyses. The highly significant correlation coefficient (r = 0.913) between silver and manganese dissolution suggests that manganese oxides are the major control on the scavenging of silver in these stream sediments, whereas iron oxides only play a secondary role in this regard. ?? 1974.

  12. Magnetic properties of iron minerals produced by natural iron- and manganese-reducing groundwater bacteria

    NASA Astrophysics Data System (ADS)

    Abrajevitch, Alexandra; Kondratyeva, Lubov M.; Golubeva, Evgeniya M.; Kodama, Kazuto; Hori, Rie S.

    2016-08-01

    Understanding the contribution of biogenic magnetic particles into sedimentary assemblages is a current challenge in palaeomagnetism. It has been demonstrated recently that magnetic particles produced through biologically controlled mineralization processes, such as magnetosomes from magnetotactic bacteria, contribute to the recording of natural remanent magnetization in marine and lacustrian sediments. Contributions from other, biologically induced, mineralization types, which are known from multiple laboratory experiments to include magnetic minerals, remain largely unknown. Here, we report magnetic properties of iron minerals formed by a community of iron- and manganese-reducing bacteria isolated from a natural groundwater deposit during a 2 yr long incubation experiment. The main iron phases of the biomineralized mass are lepidocrocite, goethite and magnetite, each of which has environmental significance. Unlike the majority of the previous studies that reported superparamagnetic grain size, and thus no remanence carrying capacity of biologically induced magnetite, hysteresis and first-order reversal curves measurements in our study have not detected significant superparamagnetic contribution. The biomineralized mass, instead, contains a mixture of single-domain to pseudo-single-domain and multidomain magnetite particles that are capable of carrying a stable chemical remanent magnetization. Isothermal remanent magnetization acquisition parameters and first-order reversal curves signatures of the biomineralized samples deviate from previously proposed criteria for the distinction of extracellular (biologically induced) magnetic particles in mixtures. Given its potential significance as a carrier of natural remanent magnetization, environmental requirements, distribution in nature and the efficiency in the geomagnetic field recording by biologically induced mineralization need comprehensive investigation.

  13. Biosorption of Cadmium and Manganese Using Free Cells of Klebsiella sp. Isolated from Waste Water.

    PubMed

    Hou, Yunnan; Cheng, Keke; Li, Zehua; Ma, Xiaohui; Wei, Yahong; Zhang, Lei; Wang, Yao

    2015-01-01

    In the present study, we evaluated a bacterium that was isolated from waste water for its ability to take up cadmium and manganese. The strain, identified both biochemically and by its 16S rRNA gene sequence as Klebsiella, was named Yangling I2 and was found to be highly resistant to heavy metals. Surface characterization of the bacterium via SEM revealed gross morphological changes, with cells appearing as biconcave discs after metal exposure rather than their typical rod shape. The effects of pH, temperature, heavy metal concentration, agitation and biomass concentration on the uptake of Cd(II) and Mn(II) was measured using atomic absorption spectrophotometry. The results showed that the biosorption was most affected by pH and incubation temperature, being maximized at pH 5.0 and 30°C, with absorption capacities of 170.4 and 114.1 mg/g for Cd(II) and Mn(II), respectively. Two models were investigated to compare the cells' capacity for the biosorption of Cd and Mn, and the Langmuir model based on fuzzy linear regression was found to be close to the observed absorption curves and yield binding constants of 0.98 and 0.86 for Cd and Mn, respectively. This strain of Klebsiella has approximately ten times the absorption capacity reported for other strains and is promising for the removal of heavy metals from waste water.

  14. Investigations of Cadmium Manganese Telluride Crystals for Room-Temperature Radiation Detection

    SciTech Connect

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

    2009-10-06

    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) measurements, and low-temperature photoluminescence spectra, and we also assessed their responses as detectors to irradiation exposure. The crystal from the stable growth region proved superior to that from the last-to-freeze region; it is a single-grain crystal, free of twins, and displayed a resistivity higher by two orders-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}){sub e} value was 2.6 x 10{sup -3} cm{sup 2}/V, which is acceptable for thin detectors, including for applications in medicine.

  15. Transcriptional and Biochemical Effects of Cadmium and Manganese on the Defense System of Octopus vulgaris Paralarvae

    PubMed Central

    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 μg/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

  16. Biosorption of Cadmium and Manganese Using Free Cells of Klebsiella sp. Isolated from Waste Water

    PubMed Central

    Hou, Yunnan; Cheng, Keke; Li, Zehua; Ma, Xiaohui; Wei, Yahong; Zhang, Lei; Wang, Yao

    2015-01-01

    In the present study, we evaluated a bacterium that was isolated from waste water for its ability to take up cadmium and manganese. The strain, identified both biochemically and by its 16S rRNA gene sequence as Klebsiella, was named Yangling I2 and was found to be highly resistant to heavy metals. Surface characterization of the bacterium via SEM revealed gross morphological changes, with cells appearing as biconcave discs after metal exposure rather than their typical rod shape. The effects of pH, temperature, heavy metal concentration, agitation and biomass concentration on the uptake of Cd(II) and Mn(II) was measured using atomic absorption spectrophotometry. The results showed that the biosorption was most affected by pH and incubation temperature, being maximized at pH 5.0 and 30°C, with absorption capacities of 170.4 and 114.1 mg/g for Cd(II) and Mn(II), respectively. Two models were investigated to compare the cells’ capacity for the biosorption of Cd and Mn, and the Langmuir model based on fuzzy linear regression was found to be close to the observed absorption curves and yield binding constants of 0.98 and 0.86 for Cd and Mn, respectively. This strain of Klebsiella has approximately ten times the absorption capacity reported for other strains and is promising for the removal of heavy metals from waste water. PMID:26505890

  17. 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 μg/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).

  18. Maternal Cadmium, Iron and Zinc Levels, DNA Methylation and Birth Weight

    EPA Science Inventory

    BACKGROUND:Cadmium (Cd) is a ubiquitous and environmentally persistent toxic metal that has been implicated in neurotoxicity, carcinogenesis and obesity and essential metals including zinc (Zn) and iron (Fe) may alter these outcomes. However mechanisms underlying these relationsh...

  19. 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

  20. In vitro susceptibility of the oomycete Pythium insidiosum to metallic compounds containing cadmium, lead, copper, manganese or zinc.

    PubMed

    Ribeiro, Tatiana Corrêa; Weiblen, Carla; Botton, Sônia de Avila; Pereira, Daniela Isabel Brayer; de Jesus, Francielli Pantella Kunz; Verdi, Camila Marina; Gressler, Leticia Trevisan; Sangioni, Luís Antonio; Santurio, Janio Morais

    2016-11-05

    Pythium insidiosum is an aquatic oomycete that causes pythiosis, an important and severe disease of difficult treatment that affects humans, domestic and wild animals. This infection is often described in horses in Brazil and humans in Thailand. In clinical practice, we have observed many cases that do not respond to available therapies, indicating the need to explore alternative therapeutic approaches. In this sense, studies using metal compounds in conjunction with available antimicrobial agents have been demonstrated greater antimicrobial activity. Thus, in this research, we tested in vitro activities of metallic compounds containing cadmium, lead, copper, manganese, or zinc against 23 isolates of P. insidiosum The assays were performed by broth microdilution based on CLSI M38-A2 document. The minimum inhibitory and fungicidal concentrations were established for all isolates. Copper acetate and cadmium acetate showed the highest inhibitory effects, with minimal inhibitory concentration ranging from 4-64 μg/ml and 16-256 μg/ml, respectively. The mean geometric for minimal fungicidal concentrations were, respectively, 26 μg/ml and 111.43 μg/ml for copper acetate and cadmium acetate. These results suggest that copper and cadmium can inhibit P. insidiosum growth, highlighting the greater inhibitory activity of copper acetate. In addition, our results propose that copper and/or cadmium compounds can be used in upcoming researches to formulate effective new complexed drugs against P. insidiosum in in vitro and in vivo experimental models.

  1. Geological reconnaissance of some Uruguayan iron and manganese deposits in 1962

    USGS Publications Warehouse

    Wallace, Roberts Manning

    1976-01-01

    Three mineralized areas lie in an area near the town of Minas de Corrales in the Departamento de Rivera; they are the Cerro Amelia, the Cerro de Papagayo, and the Cerro Iman. The Cerro Amelia is composed of small bands of iron-rich rock separated by an amphibolitic or mafic rock. Selective mining would be necessary to extract the 31,000 tons per meter of depth of iron-rich rock that ranges from 15 to 40 percent metallic iron. The Cerro de Papagayo district contains many small, rich deposits of ferruginous manganese ore. The ratio of Mn to Fe varies widely within each small deposit as well as from deposit to deposit. Some ferruginous manganese ore contains 50-55 percent manganese dioxide. Although there are many thousands of tons of ore in the district, small-scale mining operations are imperative. One deposit, the Cerro Avestuz manganese mine, was visited. The manganese ore body lies within contorted highly metamorphosed itabirite that contains both hard low grade and soft high grade ferruginous manganese ores estimated to average 40 percent Mn. About 38,000 tons of manganese ore is present in this deposit. The Cerro Iman is a large block of itabirite that contains about 40 percent Fe. The grade is variable and probably runs from less than 35 percent Fe to more than 50 percent Fe. No exploration has been done on this deposit. It is recommended that the Cerro de Iman area be geologically mapped in detail, and that a geological reconnaissance be made of the area that is between the Cuchilla de Corrales and the Cuchilla de Areycua/Cuchilla del Cerro Pelado area.

  2. Biomonitoring of arsenic, cadmium, lead, manganese and mercury in urine and hair of children living near mining and industrial areas.

    PubMed

    Molina-Villalba, Isabel; Lacasaña, Marina; Rodríguez-Barranco, Miguel; Hernández, Antonio F; Gonzalez-Alzaga, Beatriz; Aguilar-Garduño, Clemente; Gil, Fernando

    2015-04-01

    Huelva (South West Spain) and its surrounding municipalities represent one of the most polluted estuaries in the world owing to the discharge of mining and industrial related pollutants in their proximity. A biomonitoring study was conducted to assess exposure to arsenic and some trace metals (cadmium, mercury, manganese and lead) in urine and scalp hair from a representative sample of children aged 6-9 years (n=261). This is the only study simultaneously analyzing those five metal elements in children urine and hair. The potential contribution of gender, water consumption, residence area and body mass index on urinary and hair metal concentrations was also studied. Urine levels of cadmium and total mercury in a proportion (25-50%) of our children population living near industrial/mining areas might have an impact on health, likely due to environmental exposure to metal pollution. The only significant correlation between urine and hair levels was found for mercury. Children living near agriculture areas showed increased levels of cadmium and manganese (in urine) and arsenic (in hair). In contrast, decreased urine Hg concentrations were observed in children living near mining areas. Girls exhibited significantly higher trace metal concentrations in hair than boys. The greatest urine arsenic concentrations were found in children drinking well/spring water. Although human hair can be a useful tool for biomonitoring temporal changes in metal concentrations, levels are not correlated with those found in urine except for total mercury, thus providing additional information.

  3. 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...

  4. Role of the node in controlling traffic of cadmium, zinc, and manganese in rice

    PubMed Central

    Yamaguchi, Noriko; Ishikawa, Satoru; Abe, Tadashi; Baba, Koji; Terada, Yasuko

    2012-01-01

    Heavy metals are transported to rice grains via the phloem. In rice nodes, the diffuse vascular bundles (DVBs), which enclose the enlarged elliptical vascular bundles (EVBs), are connected to the panicle and have a morphological feature that facilitates xylem-to-phloem transfer. To find a mechanism for restricting cadmium (Cd) transport into grains, the distribution of Cd, zinc (Zn), manganese (Mn), and sulphur (S) around the vascular bundles in node I (the node beneath the panicle) of Oryza sativa ‘Koshihikari’ were compared 1 week after heading. Elemental maps of Cd, Zn, Mn, and S in the vascular bundles of node I were obtained by synchrotron micro-X-ray fluorescence spectrometry and electron probe microanalysis. In addition, Cd K-edge microfocused X-ray absorption near-edge structure analyses were used to identify the elements co-ordinated with Cd. Both Cd and S were mainly distributed in the xylem of the EVB and in the parenchyma cell bridge (PCB) surrounding the EVB. Zn accumulated in the PCB, and Mn accumulated around the protoxylem of the EVB. Cd was co-ordinated mainly with S in the xylem of the EVB, but with both S and O in the phloem of the EVB and in the PCB. The EVB in the node retarded horizontal transport of Cd toward the DVB. By contrast, Zn was first stored in the PCB and then efficiently transferred toward the DVB. Our results provide evidence that transport of Cd, Zn, and Mn is differentially controlled in rice nodes, where vascular bundles are functionally interconnected. PMID:22291135

  5. Baseline blood levels of manganese, lead, cadmium, copper, and zinc in residents of Beijing suburb.

    PubMed

    Zhang, Long-Lian; Lu, Ling; Pan, Ya-Juan; Ding, Chun-Guang; Xu, Da-Yong; Huang, Chuan-Feng; Pan, Xing-Fu; Zheng, Wei

    2015-07-01

    Baseline blood concentrations of metals are important references for monitoring metal exposure in environmental and occupational settings. The purpose of this study was to determine the blood levels of manganese (Mn), copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) among the residents (aged 12-60 years old) living in the suburb southwest of Beijing in China and to compare the outcomes with reported values in various developed countries. Blood samples were collected from 648 subjects from March 2009 to February 2010. Metal concentrations in the whole blood were determined by ICP-MS. The geometric means of blood levels of Mn, Cu, Zn, Pb and Cd were 11.4, 802.4, 4665, 42.6, and 0.68 µg/L, respectively. Male subjects had higher blood Pb than the females, while the females had higher blood Mn and Cu than the males. There was no gender difference for blood Cd and Zn. Smokers had higher blood Cu, Zn, and Cd than nonsmokers. There were significant age-related differences in blood levels of all metals studied; subjects in the 17-30 age group had higher blood levels of Mn, Pb, Cu, and Zn, while those in the 46-60 age group had higher Cd than the other age groups. A remarkably lower blood level of Cu and Zn in this population as compared with residents of other developed countries was noticed. Based on the current study, the normal reference ranges for the blood Mn were estimated to be 5.80-25.2 μg/L; for blood Cu, 541-1475 μg/L; for blood Zn, 2349-9492 μg/L; for blood Pb, <100 μg/L; and for blood Cd, <5.30 μg/L in the general population living in Beijing suburbs.

  6. Baseline Blood Levels of Manganese, Lead, Cadmium, Copper, and Zinc in Residents of Beijing Suburb

    PubMed Central

    Zhang, Long-Lian; Lu, Ling; Pan, Ya-Juan; Ding, Chun-Guang; Xu, Da-Yong; Huang, Chuan-Feng; Pan, Xing-Fu; Zheng, Wei

    2015-01-01

    Baseline blood concentrations of metals are important references for monitoring metal exposure in environmental and occupational settings. The purpose of this study was to determine the blood levels of manganese (Mn), copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) among the residents (aged 12–60 years old) living in the suburb southwest of Beijing in China and to compare the outcomes with reported values in various developed countries. Blood samples were collected from 648 subjects from March 2009 to February 2010. Metal concentrations in the whole blood were determined by ICP-MS. The geometric means of blood levels of Mn, Cu, Zn, Pb and Cd were 11.4, 802.4, 4665, 42.6, and 0.68 μg/L, respectively. Male subjects had higher blood Pb than the females, while the females had higher blood Mn and Cu than the males. There was no gender difference for blood Cd and Zn. Smokers had higher blood Cu, Zn, and Cd than nonsmokers. There were significant age-related differences in blood levels of all metals studied; subjects in the 17–30 age group had higher blood levels of Mn, Pb, Cu, and Zn, while those in the 46–60 age group had higher Cd than the other age groups. A remarkably lower blood level of Cu and Zn in this population as compared with residents of other developed countries was noticed. Based on the current study, the normal reference ranges for the blood Mn were estimated to be 5.80–25.2 μ/L; for blood Cu, 541–1475 μ/L; for blood Zn, 2349–9492 μ/L; for blood Pb, <100 μ/L; and for blood Cd, <5.30 μ/L in the general population living in Beijing suburbs. PMID:25836720

  7. 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.

  8. Iron plaque decreases cadmium accumulation in Oryza sativa L. and serves as a source of iron.

    PubMed

    Sebastian, A; Prasad, M N V

    2016-11-01

    Cadmium (Cd) contamination occurs in paddy soils; hence it is necessary to reduce Cd content of rice. Application and mode of action of ferrous sulphate in minimizing Cd in rice was monitored in the present study. Pot culture with Indian rice variety Swarna (MTU 7029) was maintained in Cd-spiked soil containing ferrous sulphates, which is expected to reduce Cd accumulation in rice. Responses in rhizosphere pH, root surface, metal accumulation in plant and molecular physiological processes were monitored. Iron plaque was induced on root surfaces after FeSO4 application and the amount of Fe in plaque reduced with increases in Cd in the soil. Rhizosphere pH decreased during plaque formation and became more acidic due to secretion of organic acids from the roots under Cd treatment. Moreover, iron chelate reductase activity increased with Cd treatment, but in the absence of Cd, activity of this enzyme increased in plaque-induced plants. Cd treatment caused expression of OsYSL18, whereas OsYSL15 was expressed only in roots without iron plaque. Fe content of plants increased during plaque formation, which protected plants from Cd-induced Fe deficiency and metal toxicity. This was corroborated with increased biomass, chlorophyll content and quantum efficiency of photo-synthesis among plaque-induced plants. We conclude that ferrous sulphate-induced iron plaque prevents Cd accumulation and Fe deficiency in rice. Iron released from plaque via organic acid mediated dissolution during Cd stress.

  9. 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

  10. Manganese

    Integrated Risk Information System (IRIS)

    Manganese ; CASRN 7439 - 96 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effect

  11. 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 μg/L), low normal (15.0-<30.0 μg/L for girls, 15.0-<50.0 μg/L for boys), or normal (≥30.0 μg/L for girls, ≥50.0 μg/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.

  12. Cadmium exposure affects iron acquisition in barley (Hordeum vulgare) seedlings.

    PubMed

    Astolfi, Stefania; Ortolani, Maria R; Catarcione, Giulio; Paolacci, Anna R; Cesco, Stefano; Pinton, Roberto; Ciaffi, Mario

    2014-12-01

    This study addresses the question of the interference between iron (Fe) nutrition and cadmium (Cd) toxicity at the level of growth performance, phytosiderophores (PS) release, micronutrient accumulation and expression of genes involved in Fe homeostasis in barley seedlings, a plant with strategy II-based response to Fe shortage. Cd exposure induced responses similar to those of genuine Fe deficiency also in Fe-sufficient plants. Most genes involved in PS biosynthesis and secretion (HvNAS3, HvNAS4, HvNAS6, HvNAS7, HvNAAT-A, HvDMAS1 and HvTOM1) induced by Fe deprivation were also significantly upregulated in the presence of Cd under Fe sufficient conditions. Accordingly, the enhanced expression of these genes in roots under Cd exposure was accompanied by an increase of PS release. However, induced expression of HvIRO2 and the downregulation of HvIDEF1 and HvIRT1, after Cd exposure, suggested the presence of a pathway that induces HvIRO2-mediated PS biosynthesis under Cd stress, which probably is not simply caused by Fe deficiency. The downregulation of HvIRT1 and HvNramp5 may represent a protective mechanism at transcriptional level against further Cd uptake by these transporters. These results likely indicate that Cd itself may be able to activate Fe acquisition mechanism in an Fe-independent manner.

  13. Iron et al.: Incorporation of Manganese in the Crystal Lattice of Magnetosome Magnetite

    NASA Astrophysics Data System (ADS)

    Prozorov, Tanya; Perez-Gonzalez, Teresa; Jimenez-Lopez, Concepcion; Mallapragada, Surya K.; Howse, Paul; Bazylinski, Dennis A.; Prozorov, Ruslan

    2010-03-01

    Incorporation of foreign metal into the crystal matrix of the magnetotactic bacterial magnetite has been attempted worldwide. Recently, presence of small amounts of cobalt and manganese in magnetosome magnetite crystals in cultured and uncultured magnetotactic bacteria, respectively, was reported. Magnetization of the uncultured cells and their magnetosomes were not determined, while only marginal changes in the magnetic properties of the cultured cobalt-grown cells and their magnetosomes were observed, however no evidence of incorporation of these metals into the crystalline lattice was presented. We grew cells of a magnetotactic bacterium, Magnetospirillum gryphiswaldense strain MSR-1, in the presence of manganese, ruthenium, zinc and vanadium, of which only manganese was incorporated within the magnetosome magnetite crystals. For the first time we demonstrate that the magnetic properties of magnetite crystals of magnetotactic bacteria can be significantly altered by the incorporation of metal ions, other than iron, in the crystal structure, as signaled by a major shift in the Verwey transition.

  14. Occupational exposure to manganese, copper, lead, iron, mercury and zinc and the risk of Parkinson's disease.

    PubMed

    Gorell, J M; Johnson, C C; Rybicki, B A; Peterson, E L; Kortsha, G X; Brown, G G; Richardson, R J

    1999-01-01

    A population-based case-control study was conducted in the Henry Ford Health System (HFHS) in metropolitan Detroit to assess occupational exposures to manganese, copper, lead, iron, mercury and zinc as risk factors for Parkinson's disease (PD). Non-demented men and women 50 years of age who were receiving primary medical care at HFHS were recruited, and concurrently enrolled cases (n = 144) and controls (n = 464) were frequency-matched for sex, race and age (+/- 5 years). A risk factor questionnaire, administered by trained interviewers, inquired about every job held by each subject for 6 months from age 18 onward, including a detailed assessment of actual job tasks, tools and environment. An experienced industrial hygienist, blinded to subjects' case-control status, used these data to rate every job as exposed or not exposed to one or more of the metals of interest. Adjusting for sex, race, age and smoking status, 20 years of occupational exposure to any metal was not associated with PD. However, more than 20 years exposure to manganese (Odds Ratio [OR] = 10.61, 95% Confidence Interval [CI] = 1.06, 105.83) or copper (OR = 2.49, 95% CI = 1.06,5.89) was associated with PD. Occupational exposure for > 20 years to combinations of lead-copper (OR = 5.24, 95% CI = 1.59, 17.21), lead-iron (OR = 2.83, 95% CI = 1.07,7.50), and iron-copper (OR = 3.69, 95% CI = 1.40,9.71) was also associated with the disease. No association of occupational exposure to iron, mercury or zinc with PD was found. A lack of statistical power precluded analyses of metal combinations for those with a low prevalence of exposure (i.e., manganese, mercury and zinc). Our findings suggest that chronic occupational exposure to manganese or copper, individually, or to dual combinations of lead, iron and copper, is associated with PD.

  15. Removal of Arsenic, Iron, Manganese, and Ammonia in Drinking Water: Nagaoka International Corporation CHEMILES NCL Series Water Treatment System

    EPA Science Inventory

    The Nagaoka International Corporation CHEMILES NCL Series system was tested to verify its performance for the reduction of multiple contaminants including: arsenic, ammonia, iron, and manganese. The objectives of this verification, as operated under the conditions at the test si...

  16. [Analysis on the variation characteristics of iron and manganese concentration and its genesis in Changtan Reservoir in Taizhou, Zhejiang Province].

    PubMed

    Liu, Shu-Yuan; Zheng, Chen; Yuan, Qi; Wang, Xian-Bing; Wang, Zi-Yan

    2014-10-01

    Changtan Reservoir in Taizhou City Zhejiang Province and its inflow rivers were surveyed in January and from April to December in 2013. Based on those data and the water quality monitoring data in Changtan Reservoir collected in previous years, the change characteristics of iron and manganese concentrations in source water reservoir were investigated. Furthermore, the causes of water pollution by iron and manganese were discussed based on the variation of water temperature, dissolved oxygen (DO) in reservoir with water depth. The results showed that the seasonal variation characteristics of iron and the manganese concentrations in reservoir were much in evidence. Their concentrations were high from June to August and the highest values over the years at the outlet of Changtan Reservoir were 2.38 mg · L(-1) and 1.24 mg · L(-1), respectively. The iron and the manganese concentrations exceeded the Surface Water Environment Quality Standard (GB 383822002) of 0.3 mg · L(-1) and 0.1 mg · L(-1) from May to October. And in 2013, their highest values in the reservoir outlet exceeded the standard by 5. 6 times and 12. 4 times, respectively. The maxima of iron and manganese concentrations in the major rivers were 0.89 mg · L(-1) and 0.56 mg · L(-1), which were lower than those in the reservoir outlet. The comprehensive analysis result indicated that the exogenous pollution was not the major source of iron and manganese in the reservoir. The iron and manganese concentration at the bottom of the reservoir reached the maximum in July, 2.42 mg · L(-1) and 1.20 mg · L(-1), respectively. The typical vertical distribution of temperature, DO and iron and manganese concentrations in the reservoir in summer showed that seasonal anoxic environment caused by the thermal stratification led to the release of iron manganese from the deposits. The endogenous pollution caused by thermal stratification effect was the direct cause for the high iron and manganese concentrations in water

  17. Content of total iron, copper and manganese in liver of animals during hypokinesia, muscle activity and process of recovery

    NASA Technical Reports Server (NTRS)

    Potapovich, G. M.; Taneyeva, G. V.; Uteshev, A. B.

    1980-01-01

    It is shown that the content of total iron, copper and manganese in the liver of animals is altered depending on the intensity and duration of their swimming. Hypodynamia for 7 days does not alter the concentration of iron, but sufficiently increases the content of copper and manganese. The barometric factor effectively influences the maintenance of constancy in the content of microelements accumulated in the liver after intensive muscle activity.

  18. Baseline blood levels of manganese, lead, cadmium, copper, and zinc in residents of Beijing suburb

    SciTech Connect

    Zhang, Long-Lian; Lu, Ling; Pan, Ya-Juan; Ding, Chun-Guang; Xu, Da-Yong; Huang, Chuan-Feng; Pan, Xing-Fu; Zheng, Wei

    2015-07-15

    Baseline blood concentrations of metals are important references for monitoring metal exposure in environmental and occupational settings. The purpose of this study was to determine the blood levels of manganese (Mn), copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) among the residents (aged 12–60 years old) living in the suburb southwest of Beijing in China and to compare the outcomes with reported values in various developed countries. Blood samples were collected from 648 subjects from March 2009 to February 2010. Metal concentrations in the whole blood were determined by ICP-MS. The geometric means of blood levels of Mn, Cu, Zn, Pb and Cd were 11.4, 802.4, 4665, 42.6, and 0.68 µg/L, respectively. Male subjects had higher blood Pb than the females, while the females had higher blood Mn and Cu than the males. There was no gender difference for blood Cd and Zn. Smokers had higher blood Cu, Zn, and Cd than nonsmokers. There were significant age-related differences in blood levels of all metals studied; subjects in the 17–30 age group had higher blood levels of Mn, Pb, Cu, and Zn, while those in the 46–60 age group had higher Cd than the other age groups. A remarkably lower blood level of Cu and Zn in this population as compared with residents of other developed countries was noticed. Based on the current study, the normal reference ranges for the blood Mn were estimated to be 5.80–25.2 μg/L; for blood Cu, 541–1475 μg/L; for blood Zn, 2349–9492 μg/L; for blood Pb, <100 μg/L; and for blood Cd, <5.30 μg/L in the general population living in Beijing suburbs. - Highlights: • Baseline blood levels of metals in residents of Beijing suburb are investigated. • BMn and BPb in this cohort are higher than those in other developed countries. • Remarkably lower blood levels of Cu and Zn in this Chinese cohort are noticed. • The reference values for blood levels of Mn, Cu, Zn, Pb, and Cd are established.

  19. 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 [δ-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) μg/l. Women with any HFE variant allele had 12% lower blood manganese concentrations than women with no variant alleles (β = -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

  20. 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

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

    PubMed

    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.

  2. Modified clinoptilolite in the removal of iron and manganese from water

    NASA Astrophysics Data System (ADS)

    Barloková, D.; Ilavský, J.

    2012-11-01

    It is necessary to treat water intended for drinking purposes in many cases to meet the requirements of the Regulation of the Government of the Slovak Republic No. 496/2010 on Drinking Water. There is a tendency to look for technology with new, more efficient and cost-effective materials and technologies. The goal of this study is to compare activated natural zeolite known as clinoptilolite (rich deposits of clinoptilolite were found in the region of East Slovakia Region in the 1980s) with the imported Greensand and Cullsorb materials in the removal of iron and manganese from water. The results obtained from experiments carried out at WTP Kúty prove that Klinopur-Mn is suitable for the removal of iron and manganese from water and is comparable with the imported materials.

  3. OPT3 is a phloem-specific iron transporter that is essential for systemic iron signaling and redistribution of iron and cadmium in arabidopsis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Iron is essential for both plant growth and human health and nutrition. Cadmium, on the other hand, is a non-essential and highly toxic element that competes with iron for uptake and partitioning in plant tissues, posing a threat to crop productivity and human health. Knowledge of signaling mechanis...

  4. 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.

  5. The concentration of manganese, iron and strontium in bone of red fox Vulpes vulpes (L. 1758).

    PubMed

    Budis, Halina; Kalisinska, Elzbieta; Lanocha, Natalia; Kosik-Bogacka, Danuta I

    2013-12-01

    The aims of the study were to determine manganese (Mn), iron (Fe) and strontium (Sr) concentrations in fox bone samples from north-western Poland and to examine the relationships between the bone Mn, Fe and Sr concentrations and the sex and age of the foxes. In the studied samples of fox cartilage, cartilage with adjacent compact bone, compact bone and spongy bone, the concentrations of the analysed metals had the following descending order: Fe > Sr > Mn. The only exception was in compact bone, in which the concentrations were arranged in the order Sr > Fe > Mn. Manganese concentrations were significantly higher in cartilage, compact bone and cartilage with compact bone than in spongy bone. Iron concentrations were higher in cartilage and spongy bone compared with compact bone. Strontium concentrations were greater in compact bone than in cartilage and spongy bone. The manganese, iron and strontium concentrations in the same type of bone material in many cases correlated with each other, with the strongest correlation (r > 0.70) between Mn and Fe in almost all types of samples. In addition, concentrations of the same metals in different bone materials were closely correlated for Mn and Fe in cartilage and cartilage with adjacent compact bone, and for Sr in compact bone and cartilage with compact bone. In the fox from NW Poland, there were no statistically significant differences in Mn, Fe and Sr in any of the types of bone material between the sexes and immature and adult foxes.

  6. Abu Zenima synthetic zeolite for removing iron and manganese from Assiut governorate groundwater, Egypt

    NASA Astrophysics Data System (ADS)

    Farrag, Abd El Hay Ali; Abdel Moghny, Th.; Mohamed, Atef Mohamed Gad; Saleem, Saleem Sayed; Fathy, Mahmoud

    2016-06-01

    Groundwater in Upper Egypt especially in Assiut Governorate is considered the second source of fresh water and used for drinking, agriculture, domestic and industrial purposes. Unfortunately, it is characterized by high concentrations of iron and manganese ions. The study aimed at synthesizing zeolite-4A from kaolinite for removing the excess iron and manganese ions from Assiut Governorate groundwater wells. Therefor, the kaolinite was hydrothermally treated through the metakaolinization and zeolitization processes to produce crystalline zeolite-4A. The chemical composition of crystalline zeolite-4A and its morphology were then characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Then the column experiments were conducted to study the performance of crystalline salt-4A as ion exchange and investigate their operating parameters and regeneration conditions. Thomas and Yoon-Nelson models were applied to predict adsorption capacity and the time required for 50 % breakthrough curves. The effects of initial concentrations of 600 and 1000 mg L-1 for Fe2+ and Mn2+, feed flow rate of 10-30 ml/min, and height range of 0.4-1.5 cm on the breakthrough behavior of the adsorption system were determined. The obtained results indicated that the synthesized zeolite-A4 can remove iron and manganese ions from groundwater to the permissible limit according to the standards drinking water law.

  7. Sorption of ferric iron from ferrioxamine B to synthetic and biogenic layer type manganese oxides

    NASA Astrophysics Data System (ADS)

    Duckworth, Owen W.; Bargar, John R.; Sposito, Garrison

    2008-07-01

    Siderophores are biogenic chelating agents produced in terrestrial and marine environments that increase the bioavailability of ferric iron. Recent work has suggested that both aqueous and solid-phase Mn(III) may affect siderophore-mediated iron transport, but scant information appears to be available about the potential roles of layer type manganese oxides, which are relatively abundant in soils and the oligotrophic marine water column. To probe the effects of layer type manganese oxides on the stability of aqueous Fe-siderophore complexes, we studied the sorption of ferrioxamine B [Fe(III)HDFOB +, an Fe(III) chelate of the trihydroxamate siderophore desferrioxamine B (DFOB)] to two synthetic birnessites [layer type Mn(III,IV) oxides] and a biogenic birnessite produced by Pseudomonas putida GB-1. We found that all of these predominantly Mn(IV) oxides greatly reduced the aqueous concentration of Fe(III)HDFOB + at pH 8. Analysis of Fe K-edge EXAFS spectra indicated that a dominant fraction of Fe(III) associated with the Mn(IV) oxides is not complexed by DFOB as in solution, but instead Fe(III) is specifically adsorbed to the mineral structure at multiple sites, thus indicating that the Mn(IV) oxides displaced Fe(III) from the siderophore complex. These results indicate that layer type manganese oxides, including biogenic minerals, may sequester iron from soluble ferric complexes. We conclude that the sorption of iron-siderophore complexes may play a significant role in the bioavailability and biogeochemical cycling of iron in marine and terrestrial environments.

  8. Cadmium toxicity induced alterations in the root proteome of green gram in contrasting response towards iron supplement.

    PubMed

    Muneer, Sowbiya; Hakeem, Khalid Rehman; Mohamed, Rozi; Lee, Jeong Hyun

    2014-04-15

    Cadmium signifies a severe threat to crop productivity and green gram is a notably iron sensitive plant which shows considerable variation towards cadmium stress. A gel-based proteomics analysis was performed with the roots of green gram exposed to iron and cadmium combined treatments. The resulting data show that twenty three proteins were down-regulated in iron-deprived roots either in the absence (-Fe/-Cd) or presence (-Fe/+Cd) of cadmium. These down-regulated proteins were however well expressed in roots under iron sufficient conditions, even in the presence of cadmium (+Fe/+Cd). The functional classification of these proteins determined that 21% of the proteins are associated with nutrient metabolism. The other proteins in higher quantities are involved in either transcription or translation regulation, and the rest are involved in biosynthesis metabolism, antioxidant pathways, molecular chaperones and stress response. On the other hand, several protein spots were also absent in roots in response to iron deprivation either in absence (-Fe/-Cd) or presence (-Fe/+Cd) of cadmium but were well expressed in the presence of iron (+Fe/+Cd). Results suggest that green gram plants exposed to cadmium stress are able to change the nutrient metabolic balance in roots, but in the mean time regulate cadmium toxicity through iron supplements.

  9. Cadmium Toxicity Induced Alterations in the Root Proteome of Green Gram in Contrasting Response towards Iron Supplement

    PubMed Central

    Muneer, Sowbiya; Hakeem, Khalid Rehman; Mohamed, Rozi; Lee, Jeong Hyun

    2014-01-01

    Cadmium signifies a severe threat to crop productivity and green gram is a notably iron sensitive plant which shows considerable variation towards cadmium stress. A gel-based proteomics analysis was performed with the roots of green gram exposed to iron and cadmium combined treatments. The resulting data show that twenty three proteins were down-regulated in iron-deprived roots either in the absence (−Fe/−Cd) or presence (−Fe/+Cd) of cadmium. These down-regulated proteins were however well expressed in roots under iron sufficient conditions, even in the presence of cadmium (+Fe/+Cd). The functional classification of these proteins determined that 21% of the proteins are associated with nutrient metabolism. The other proteins in higher quantities are involved in either transcription or translation regulation, and the rest are involved in biosynthesis metabolism, antioxidant pathways, molecular chaperones and stress response. On the other hand, several protein spots were also absent in roots in response to iron deprivation either in absence (−Fe/−Cd) or presence (−Fe/+Cd) of cadmium but were well expressed in the presence of iron (+Fe/+Cd). Results suggest that green gram plants exposed to cadmium stress are able to change the nutrient metabolic balance in roots, but in the mean time regulate cadmium toxicity through iron supplements. PMID:24739807

  10. 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.

  11. 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

  12. Expanding the menu for carnivorous plants: uptake of potassium, iron and manganese by carnivorous pitcher plants.

    PubMed

    Adlassnig, Wolfram; Steinhauser, Georg; Peroutka, Marianne; Musilek, Andreas; Sterba, Johannes H; Lichtscheidl, Irene K; Bichler, Max

    2009-12-01

    Carnivorous plants use animals as fertiliser substitutes which allow them to survive on nutrient deficient soils. Most research concentrated on the uptake of the prey's nitrogen and phosphorus; only little is known on the utilisation of other elements. We studied the uptake of three essential nutrients, potassium, iron and manganese, in three species of carnivorous pitcher plants (Cephalotus follicularis LaBilladiere, Sarracenia purpureaL., Heliamphora nutans Bentham). Using relatively short-lived and gamma-emitting radiotracers, we significantly improved the sensitivity compared to conventional protocols and gained the following results. We demonstrated the uptake of trace elements like iron and manganese. In addition, we found direct evidence for the uptake of potassium into the pitcher tissue. Potassium and manganese were absorbed to virtually 100% if offered in physiological concentrations or below in Cephalotus. Analysis of pitcher fluid collected in the natural habitat showed that uptake was performed here as efficiently as in the laboratory. The absorption of nutrients is an active process depending on living glandular cells in the pitcher epidermis and can be inhibited by azide. Unphysiologically high amounts of nutrients were taken up for a short time, but after a few hours the absorbing cells were damaged, and uptake stopped. Absorption rates of pitcher leaves from plants under controlled conditions varied highly, indicating that each trap is functionally independent. The comparison of minerals in typical prey with the plants' tissues showed that a complete coverage of the plants' needs by prey capture is improbable.

  13. Preparation of polyacrylnitrile (PAN)/ Manganese oxide based activated carbon nanofibers (ACNFs) for adsorption of Cadmium (II) from aqueous solution

    NASA Astrophysics Data System (ADS)

    Abdullah, N.; Yusof, N.; Jaafar, J.; Ismail, AF; Che Othman, F. E.; Hasbullah, H.; Salleh, W. N. W.; Misdan, N.

    2016-06-01

    In this work, activated carbon nanofibers (ACNFs) from precursor polyacrylnitrile (PAN) and manganese oxide (MnO2) were prepared via electrospinning process. The electrospun PAN/MnO2-based ACNFs were characterised in term of its morphological structure and specific surface area using SEM and BET analysis respectively. The comparative adsorption study of cadmium (II) ions from aqueous solution between the neat ACNFs, composite ACNFs and commercial granular activated carbon was also conducted. SEM analysis illustrated that composite ACNFs have more compact fibers with presence of MnO2 beads with smaller fiber diameter of 437.2 nm as compared to the neat ACNFs which is 575.5 nm. BET analysis elucidated specific surface area of ACNFs/MnO2 to be 67 m2/g. Under adsorption study, it was found out that Cd (II) removal by ACNFs/MnO2 was the highest (97%) followed by neat ACNFs (96%) and GAC (74%).

  14. OPT3 Is a Phloem-Specific Iron Transporter That Is Essential for Systemic Iron Signaling and Redistribution of Iron and Cadmium in Arabidopsis[W][OPEN

    PubMed Central

    Zhai, Zhiyang; Gayomba, Sheena R.; Jung, Ha-il; Vimalakumari, Nanditha K.; Piñeros, Miguel; Craft, Eric; Rutzke, Michael A.; Danku, John; Lahner, Brett; Punshon, Tracy; Guerinot, Mary Lou; Salt, David E.; Kochian, Leon V.; Vatamaniuk, Olena K.

    2014-01-01

    Iron is essential for both plant growth and human health and nutrition. Knowledge of the signaling mechanisms that communicate iron demand from shoots to roots to regulate iron uptake as well as the transport systems mediating iron partitioning into edible plant tissues is critical for the development of crop biofortification strategies. Here, we report that OPT3, previously classified as an oligopeptide transporter, is a plasma membrane transporter capable of transporting transition ions in vitro. Studies in Arabidopsis thaliana show that OPT3 loads iron into the phloem, facilitates iron recirculation from the xylem to the phloem, and regulates both shoot-to-root iron signaling and iron redistribution from mature to developing tissues. We also uncovered an aspect of crosstalk between iron homeostasis and cadmium partitioning that is mediated by OPT3. Together, these discoveries provide promising avenues for targeted strategies directed at increasing iron while decreasing cadmium density in the edible portions of crops and improving agricultural productivity in iron deficient soils. PMID:24867923

  15. 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.

  16. 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.

    2016-11-01

    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.

  17. Sulfide, iron, manganese, and phosphate in the deep water of the Chesapeake Bay during anoxia

    NASA Astrophysics Data System (ADS)

    Gavis, Jerome; Grant, Virginia

    1986-10-01

    Concentrations of dissolved oxygen and sulfide, and of dissolved and particulate iron, manganese, and phosphate were measured as functions of salinity at a station in the Chesapeake Bay during stratification and deep water anoxia in spring and summer, 1981. The observed concentration/salinity profiles showed that oxygen was transported in a direction opposite to that of salt, while dissolved sulfide was transported in the same direction as salt through the anoxic water to be oxidized in oxygen consumption zones located below the steepest parts of the halocline. Both oxygen and sulfide were transported conservatively on 18 June. Their fluxes were 1·2 and 2 mol m -2 d -1, respectively. The oxygen flux was 30% of that stoichiometrically needed to oxidize the sulfide transported, suggesting that the oxygen consumption zone was advancing to shallower, less saline water, thus increasing the volume of anoxic water. Although oxygen was transported conservatively, sulfide was produced as it was transported through the anoxic water on 8 July. The anoxic water was supersaturated with respect to ferrous sulfide on 18 June, but most of the anoxic water was saturated on 8 July. Precipitation of ferrous sulfide had little effect on the sulfide flux on 18 June. The manganese(II) concentration/salinity profile exhibited a maximum in the oxygen consumption zone on 18 June. On 8 July the profile was independent of salinity at high salinities. Iron(II) and manganese(II) consumed little if any oxygen in the oxygen consumption zone. Soluble reactive phosphate was transported conservatively through the anoxic water on 18 June. It was produced as it was transported on 8 July. All of the phosphate was consumed in the oxygen consumption zones by sulfide oxidizing bacteria. On 18 June its flux, estimated to be 2·8 mmol m -2 d -1, was less than 10% of that required for bacterial oxidation of the sulfide reaching the oxygen consumption zone. The rest was oxidized chemically. The growth and

  18. The photochemistry of manganese and the origin of Banded Iron Formations.

    PubMed

    Anbar, A D; Holland, H D

    1992-07-01

    The photochemical oxidation of Fe(2+) -hydroxide complexes dissolved in anoxic Precambrian oceans has been suggested as a mechanism to explain the deposition of Banded Iron Formations (BIFs). Photochemical studies have not yet addressed the low levels of manganese in many of these deposits, which probably precipitated from solutions bearing similar concentrations of Fe2+ and Mn2+. Depositional models must also explain the stratigraphic separation of iron and manganese ores in manganiferous BIFs. In this study, solutions containing 0.56 M NaCl and approximately 180 micromoles MnCl2 with or without 3 to 200 micromoles FeCl2 were irradiated with filtered and unfiltered UV light from a medium-pressure mercury-vapor lamp for up to 8 hours. The solutions were deaerated and buffered to pH approximately 7, and all experiments were conducted under O2-free (< 1 ppm) atmospheres. In experiments with NaCl + MnCl2, approximately 20% of the Mn2+ was oxidized and precipitated as birnessite in 8 hours. Manganese precipitation was only observed when light with lambda < 240 nm was used. In experiments with NaCl + MnCl2 + FeCl2, little manganese was lost from solution, while Fe2+ was rapidly oxidized to Fe3+ and precipitated as gamma-FeOOH or as amorphous ferric hydroxide. The Mn:Fe ratio of these precipitates was approximately 1:50, similar to the ratios observed in BIFs. A strong upper limit on the rate of manganese photo-oxidation during the Precambrian is estimated to be 0.1 mg cm-2 yr-1, a factor of 10(3) slower than the rate of iron photo-oxidation considered reasonable in BIF depositional basins. Thus, a photochemical model for the origin of oxide facies BIFs is consistent with field observations, although models that invoke molecular O2 as the oxidant of Fe2+ and Mn2+ are not precluded. Apparently, oxide facies BIFs could have formed under anoxic, as well as under mildly oxygenated atmospheres.

  19. 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

  20. Zinc, cadmium and manganese uptake by soybean from two zinc- and cadmium-amended Coastal Plain soils

    SciTech Connect

    White, M.C.; Chaney, R.L.

    1980-03-01

    Two Coastal Plain soils were used to evaluate the effects of organic matter and Fe and Mn hydrous oxides on Zn phytotoxicity, and on Zn, Cd, and Mn uptake by soybean seedlings. Fertilized Pocomoke sl and Sassafras sl were limed to pH 5.5 and 6.3 with CaCO/sub 3/ when adding Zn (six levens between 1.3 and 196 mg/kg at pH 5.5; seven levels between 1.3 and 524 mg/kg at pH 6.3). Cadmium was added at 1% of the added Zn. Beeson soybean (Glycine max L. Merr.) was grown 4 weeks, and the trifoliolate leaves evaluated for dry weight yield and for their Zn, Cd, and Mn concentrations. The higher organic matter Pocomoke soil was more effective than the Sassafras soil in reducing metal uptake, and Zn phytoxicity. Foliar Zn levels associated with yield reduction of soybean grown on Pocomoke differed with soil pH. Cadmium uptake was significantly lower on the Pocomoke soil. Foliar Mn increased to reported phytotoxic levels (> 500 mg/kg) with increased added Zn only on the Sassafras soil at pH 6.3. DTPA-extractable Zn and Cd were linear functions of added Zn and Cd for both soils; 0.01M CaCl/sub 2/-extractable Zn and Cd were curvilinear (increasing slope) functions for the Sassafras and linear for the Pocomoke soil. Thus, soil type can strongly influence Zn, Cd, and Mn uptake as well as Zn phytotoxicity to soybean. Soil organic matter appears to be more important than hydrous oxides of Fe and Mn in moderating the effects of excessive soil Zn and limiting Zn and Cd uptake. Induced metal toxicities (Mn) may depend on many factors, and should be considered an integral part of any characterization of specific metal phytotoxicities (e.g. Zn).

  1. Structural studies of iron and manganese in photosynthetic reaction centers

    SciTech Connect

    McDermott, A.E.

    1987-11-01

    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 on microwave power and temperature indicate an Orbach spin relaxation mechanism involving an excited state at 40 cm/sup -1/. This low energy contributes to its unusually anisotropic g-tensor. XAS of iron in PS I preparations containing ferredoxins A, B and X are consistent with a model with (4Fe-4S) ferredoxins, which are presumably centers A and B and (2Fe-2S) ferredoxins, which would be X. Illumination of dark-adapted Synechococcus PS II samples at 220 to 240 K results in the formation of the multiline EPR signal previously assigned as a Mn S/sub 2/ species, and g = 1.8 and 1.9 signals of Fe/sup 2 +/ Q/sub A//sup -/. In contrast to spinach, illumination at 110 to 160 K produces only a new EPR signal at g = 1.6 which we assign to another configuration of Fe/sup 2+ - Q/sup -/. Following illumination of a S/sub 1/ sample at 140 K or 215 K, the Mn x-ray absorption edge inflection energy changes from 6550 eV to 6551 eV, indicating an oxidation of Mn, and average valences greater than Mn(II). Concomitant changes in the shape of the pre-edge spectrum indicate oxidation of Mn(III) to Mn(IV). The Mn EXAFS spectrum of PS II from Synechococcus is similar in the S/sub 1/ and S/sub 2/ states, indicating O or N ligands at 1.75 +- 0.05 A, transition metal neighbor(s) at 2.75 +- 0.05 A, and N and O ligands at 2.2 A with heterogeneous bond lengths; these data demonstrate the presence of a di-..mu..-oxo bridged Mn structure. 202 refs., 40 figs., 7 tabs.

  2. THEORETICAL TECHNIQUE FOR DETERMINING THE CUMULATIVE IMPACT OF IRON AND MANGANESE OXIDATION IN STREAMS RECEIVING COAL-MINE DISCHARGE.

    USGS Publications Warehouse

    Bobay, Keith E.; Banaszak, Konrad J.; ,

    1985-01-01

    Two U. S. Geological Survey computer programs are modified and linked to predict the cumulative impact of iron and manganese oxidation in coal-mine discharge on the dissolved-chemical quality of a receiving stream. The coupled programs calculate the changes in dissolved-iron, dissolved-manganese, and dissolved-oxygen concentrations, and the pH of surface water downstream from the discharge. The cumulative impact of representative discharges from several coal mines on stream quality in a small watershed in southwestern Indiana was simulated to determine the effectiveness and sensitivity of the coupled programs.

  3. The Proteome of Copper, Iron, Zinc, and Manganese Micronutrient Deficiency in Chlamydomonas reinhardtii*

    PubMed Central

    Hsieh, Scott I.; Castruita, Madeli; Malasarn, Davin; Urzica, Eugen; Erde, Jonathan; Page, M. Dudley; Yamasaki, Hiroaki; Casero, David; Pellegrini, Matteo; Merchant, Sabeeha S.; Loo, Joseph A.

    2013-01-01

    Trace metals such as copper, iron, zinc, and manganese play important roles in several biochemical processes, including respiration and photosynthesis. Using a label-free, quantitative proteomics strategy (MSE), we examined the effect of deficiencies in these micronutrients on the soluble proteome of Chlamydomonas reinhardtii. We quantified >103 proteins with abundances within a dynamic range of 3 to 4 orders of magnitude and demonstrated statistically significant changes in ∼200 proteins in each metal-deficient growth condition relative to nutrient-replete media. Through analysis of Pearson's coefficient, we also examined the correlation between protein abundance and transcript abundance (as determined via RNA-Seq analysis) and found moderate correlations under all nutritional states. Interestingly, in a subset of transcripts known to significantly change in abundance in metal-replete and metal-deficient conditions, the correlation to protein abundance is much stronger. Examples of new discoveries highlighted in this work include the accumulation of O2 labile, anaerobiosis-related enzymes (Hyd1, Pfr1, and Hcp2) in copper-deficient cells; co-variation of Cgl78/Ycf54 and coprogen oxidase; the loss of various stromal and lumenal photosynthesis-related proteins, including plastocyanin, in iron-limited cells; a large accumulation (from undetectable amounts to over 1,000 zmol/cell) of two COG0523 domain-containing proteins in zinc-deficient cells; and the preservation of photosynthesis proteins in manganese-deficient cells despite known losses in photosynthetic function in this condition. PMID:23065468

  4. The hierarchy of transition metal homeostasis: iron controls manganese accumulation in a unicellular cyanobacterium.

    PubMed

    Sharon, Shir; Salomon, Eitan; Kranzler, Chana; Lis, Hagar; Lehmann, Robert; Georg, Jens; Zer, Hagit; Hess, Wolfgang R; Keren, Nir

    2014-12-01

    Iron and manganese are part of a small group of transition metals required for photosynthetic electron transport. Here, we present evidence for a functional link between iron and manganese homeostasis. In the unicellular cyanobacterium, Synechocystis sp. PCC 6803, Fe and Mn deprivation resulted in distinct modifications of the physiological status. The effect on growth and photosynthetic activity under Fe limitation were more severe than those observed under Mn limitation. Moreover, the intracellular elemental quotas of Fe and Mn were found to be linked. Fe limitation reduced the intracellular Mn quota. Mn limitation did not exert a reciprocal effect on Fe quotas. Microarray analysis comparing Mn and Fe limitation revealed a stark difference in the extent of the transcriptional response to the two limiting conditions, reflective of the physiological responses. The effects of Fe limitation on the transcriptional network are widespread while the effects on Mn limitation are highly specific. Our analysis also revealed an overlap in the transcriptional response of specific Fe and Mn transporters. This overlap provides a framework for explaining Fe limitation induced changes in Mn quotas.

  5. Manganese, iron and phosphorus cycling in an estuarine mudflat, Loire, France

    NASA Astrophysics Data System (ADS)

    Thibault de Chanvalon, A.; Mouret, A.; Knoery, J.; Geslin, E.; Péron, O.; Metzger, E.

    2016-12-01

    The sampling of surface sediment from two sites of a mudflat of the Loire Estuary during four contrasting seasons has led to new information about geochemical cycling under transient diagenesis fuelled by flood deposition. Based on stocks of reactive iron-oxides and manganese-oxides (ascorbate-extracted) and pore water concentrations, the progressive evolution of flood deposits is described. Three major steps are observed: at first, there is no manganese, iron and phosphorus release into pore water within the flood-deposited layer. Then, during a period of approximately 1 month, Mn oxides are consumed while the dissolved Mn concentration increases. Simultaneously, the Fe oxide-rich layer from flood deposition prevents (or at least limits) phosphorus release into pore water as shown by the increasing P/Fe ratio of the ascorbate extractions. During spring and summer, Fe oxides are reductively dissolved until complete depletion results. This period also corresponds to the saturation of Fe oxides by phosphorus and probably maximum P release to the water column. The site located closer to the shore showed higher density of benthic faunas leading to more intense bioirrigation. The importance of bioturbation on the year scale for biogeochemical processes is discussed according to both bioirrigation and biomixing processes.

  6. Mobilisation processes responsible for iron and manganese contamination of groundwater in Central Adriatic Italy.

    PubMed

    Palmucci, William; Rusi, Sergio; Di Curzio, Diego

    2016-06-01

    Iron and manganese are two of the most common contaminants that exceed the threshold imposed by international and national legislation. When these contamination occurs in groundwater, the use of the water resource is forbidden for any purposes. Several studies investigated these two metals in groundwater, but research focused in the Central Adriatic area are still lacking. Thus, the objective of this study is to identify the origin of Fe and Mn contamination in groundwater and the hydrogeochemical processes that can enrich aquifers with these metals. This work is based on hydrogeochemical and multivariate statistical analysis of analytical results undertaken on soils and groundwater. Fe and Mn contamination are widespread in the alluvial aquifers, and their distribution is regulated by local conditions (i.e. long residence time, presence of peat or organic-rich fine sediments or anthropic pollution) that control redox processes in the aquifers and favour the mobilisation of these two metals in groundwater. The concentration of iron and manganese identified within soil indicates that the latter are a concrete source of the two metals. Anthropic impact on Fe and Mn contamination of groundwater is not related to agricultural activities, but on the contrary, the contribution of hydrocarbons (e.g. spills) is evident.

  7. Pilot scale evaluation of biological and pressure clarification processes for the removal of high level of iron and manganese

    SciTech Connect

    Yannoni, C.C.; Kinsley, B.P.; Marston, T.R.

    1996-11-01

    Iron and manganese originating from groundwater supplies have a long history of causing consumer complaints in water distribution systems. Although iron and manganese are not public health concerns, they are a major concern from an aesthetic standpoint. The elevated awareness of consumers in regard to the quality of drinking water, an increase in regulations requiring additional treatment and the cost associated with developing new sources of supply, has required many utilities to implement improvements to existing facilities. Historical water quality data collected from the Connecticut Water Company`s (CWC) Westbrook Well revealed an increasing trend in iron and manganese concentrations. As a result, the existing greensand filtration facility located at the well, provides insufficient removal rates and inefficient operating cycles. Variations in operating procedures were not successful in correcting these problems. A water treatment feasibility study recommended evaluation of biological and pressure clarification processes to reduce iron (9 mg/l) and manganese (1.5 mg/l) levels below the secondary maximum contaminant levels of 0.30 and 0.05 mg/l, respectively. Assessment of these processes was accomplished through the construction and operation of a 5 gallon per minute (gpm) capacity pilot plant at the Westbrook Water Treatment Plant. Application of biological treatment for iron removal was then piloted on the existing full-scale treatment facility.

  8. Iron depletion increases manganese uptake and potentiates apoptosis through ER stress

    PubMed Central

    Seo, Young Ah; Li, Yuan; Wessling-Resnick, Marianne

    2013-01-01

    Iron deficiency is a risk factor for manganese (Mn) accumulation. Excess Mn promotes neurotoxicity but the mechanisms involved and whether iron depletion might affect these pathways is unknown. To study Mn intoxication in vivo, iron deficient and control rats were intranasally instilled with 60 mg MnCl2/kg over 3 weeks. TUNEL staining of olfactory tissue revealed that Mn exposure induced apoptosis and that iron deficiency potentiated this effect. In vitro studies using the dopaminergic SH-SY5Y cell line confirmed that Mn-induced apoptosis was enhanced by iron depletion using the iron chelator desferrioxamine. Mn has been reported to induce apoptosis through endoplasmic reticulum stress. In SH-SY5Y cells, Mn exposure induced the ER stress genes glucose regulated protein 94 (GRP94) and C/EBP homologous protein (CHOP). Increased phosphorylation of the eukaryotic translation initiation factor 2α (phospho-eIF2α) was also observed. These effects were accompanied by the activation of ER resident enzyme caspase-12, and the downstream apoptotic effector caspase-3 was also activated. All of the Mn-induced responses were enhanced by DFO treatment. Inhibitors of ER stress and caspases significantly blocked Mn-induced apoptosis and its potentiation by DFO, indicating that ER stress and subsequent caspase activation underlie cell death. Taken together, these data reveal that Mn induces neuronal cell death through ER stress and the UPR response pathway and that this apoptotic effect is potentiated by iron deficiency most likely through upregulation of DMT1. PMID:23764342

  9. Validation of In-Situ Iron-Manganese Oxide Coated Stream Pebbles as Sensors for Arsenic Source Monitoring

    NASA Astrophysics Data System (ADS)

    Blake, J.; Peters, S. C.; Casteel, A.

    2013-12-01

    Locating nonpoint source contaminant fluxes can be challenging due to the inherent heterogeneity of source and of the subsurface. Contaminants such as arsenic are a concern for drinking water quality and ecosystem health. Arsenic contamination can be the result of several natural and anthropogenic sources, and therefore it can be difficult to trace and identify major areas of arsenic in natural systems. Identifying a useful source indicator for arsenic is a crucial step for environmental remediation efforts. Previous studies have found iron-manganese oxide coated streambed pebbles as useful source indicators due to their high attraction for heavy metals in water. In this study, pebbles, surface water at baseflow and nearby rocks were sampled from the Pennypack Creek and its tributaries, in southwestern Pennsylvania, to test the ability of coated streambed pebbles as environmental source indicators for arsenic. Quartz pebbles, 5-7 cm in diameter, were sampled to minimize elemental contamination from rock chemistry. In addition, quartz provides an excellent substrate for iron and manganese coatings to form. These coatings were leached from pebbles using 4M nitric acid with 0.1% concentrated hydrochloric acid. Following sample processing, analyses were performed using an ICP-MS and the resulting data were spatially organized using ArcGIS software. Arsenic, iron and manganese concentrations in the leachate are normalized to pebble surface area and each location is reported as a ratio of arsenic to iron and manganese. Results suggest that iron-manganese coated stream pebbles are useful indicators of arsenic location within a watershed.

  10. Determination of Nickel and Manganese Contaminants in Pharmaceutical Iron Supplements Using Energy Dispersive X-ray Fluorescence.

    PubMed

    Cardoso, Pedro; Amaro, Pedro; Santos, José Paulo; de Assis, Joaquim T; Carvalho, Maria Luisa

    2017-03-01

    In this study, we investigate the capability of energy dispersive X-ray fluorescence (EDXF) spectrometry in a triaxial geometry apparatus as a fast and nondestructive determination method of both dominant and contaminant elements in pharmaceutical iron supplements. The following iron supplements brands with their respective active ingredients were analyzed: Neutrofer fólico (iron gylcinate), Anemifer (iron(II) sulfate monohydrate), Noripurum (iron(III)-hydroxide polymaltose complex), Sulferbel (iron(II) sulfate monohydrate), and Combiron Fólico (carbonyl iron). Although we observe a good agreement between the iron content obtained by the present method and that indicated in the supplement's prescribed dose, we observe contamination by manganese and nickel of up to 180 μg and 36 μg, respectively. These contents correspond to 7.2% and 14.4% of the permitted daily exposure of manganese and nickel, respectively, for an average adult individual as determined by the European Medicine Agency (EMEA). The method was successfully validated against the concentrations of several certified reference materials of biological light matrices with similar concentrations of contaminants. Moreover, we also validated our method by comparing the concentrations with those obtained with the inductively coupled plasma-atomic emission technique.

  11. 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.

  12. Enzyme activity alteration by cadmium administration to rats: the possibility of iron involvement in lipid peroxidation.

    PubMed

    Casalino, E; Sblano, C; Landriscina, C

    1997-10-15

    The specific activities of D-3-hydroxybutyrate dehydrogenase (BDH) and glutamate dehydrogenase (GDH) are reduced in the liver and kidney of rats intoxicated with 2.5 mg Cd/kg body wt and sacrificed after 24 h; conversely ketone-body concentration is strongly increased in both of these organs and blood. In the same animals a great stimulation of antioxidant enzymes glutathione reductase and glutathione peroxidase occurs. The prooxidant state induced by cadmium in liver mitochondria and microsomes is unaffected by superoxide dismutase, catalase, or mannitol, whereas it is completely blocked by vitamin E thus excluding the involvement of reactive oxygen species in this process. The mechanism by which cadmium induces lipid peroxidation has been investigated by measuring the effect of this metal on liposomes. Ninety-minute treatment of liposomes with CdCl2 does not induce any lipid peroxidation. In contrast, Fe2+ ions under the same conditions cause strong liposome peroxidation. It has also been observed that cadmium promotes a time-dependent iron release from biological membranes. When lipid peroxidation is induced by a low concentration (5 microM) of FeCl2, in place of CdCl2, the characteristics of this process and the sensitivity to the various antioxidants used are similar to those observed with Cd. From these results we conclude that the prooxidative effect of cadmium is an indirect one since it is mediated by iron. With regard to the inhibitory effect on BDH and GDH following cadmium intoxication, it does not appear to be imputable to lipid peroxidation since in vitro investigations indicate that the presence of vitamin E does not remove the inhibition at all.

  13. Lead-210, polonium-210, manganese and iron in the Cariaco Trench

    NASA Astrophysics Data System (ADS)

    Bacon, Michael P.; Brewer, Peter G.; Spencer, Derek W.; Murray, James W.; Goddard, John

    1980-02-01

    Measurements of temperature, salinity, dissolved oxygen, sulfide, 226Ra, Mn, Fe, 210Pb, 210Po, and total suspended matter from three cruises of R.V. Atlantis II in the Cariaco Trench are reported. Distributions of dissolved and particulate Mn and Fe are similar to those for the Black Sea and reflect similar diffusion and redox-potential controls. Results for 210Pb and 226Ra in the anoxic deep water indicate a residence time for 210Pb in solution of less than two years. Particulate 210Pb results suggest that removal occurs largely by incorporation into metal sulfide phases forming in the water column. There is also evidence for precipitation of 210Pb with manganese oxide or iron hydroxide just above the O 2-H 2S interface. In the upper 300 m, 210Po is enriched by 55% over radioactive equilibrium with 210Pb. Possible sources of this excess include the bottom sediments and the water upwelling along the Venezuelan coast.

  14. Sources and leaching of manganese and iron in the Saigon River Basin, Vietnam.

    PubMed

    Ha, Nguyen Thi Van; Takizawa, Satoshi; Oguma, Kumiko; Phuoc, Nguyen Van

    2011-01-01

    High concentrations of manganese and iron in the Saigon River are major problems for the water supply in Ho Chi Minh City (HCMC), Viet Nam. To identify their sources and leaching processes, we surveyed water quality along the Saigon River and ran batch leaching tests using soil and sediment samples. Two important leaching processes were identified: acidic leaching from acid sulfate soil (ASS) in the middle reaches of the river, and Mn dissolution and Fe reduction from sediments in the downstream reaches. Low pH caused the concurrent release of Fe and Mn from the ASS. In contrast, anoxia caused the release of Fe but not Mn from the sediments, whereas low pH facilitated Mn dissolution. Sediments are a more important source of Mn because of their higher Mn contents (10 times) and release rates (14 times) than those from ASS.

  15. Acrylate intercalation and in situ polymerization in iron-, cobalt-, or manganese-substituted nickel hydroxides.

    PubMed

    Vaysse, C; Guerlou-Demourgues, L; Duguet, E; Delmas, C

    2003-07-28

    A chimie douce route based on successive redox and exchange reactions has allowed us to prepare new hybrid organic-inorganic materials, composed of polyacrylate macromolecules intercalated into layered double hydroxides (LDHs), deriving from Ni(OH)(2). Monomer intercalation and in situ polymerization mechanisms have appeared to be strongly dependent upon the nature of the substituting cation in the slabs. In the case of iron-based LDHs, a phase containing acrylate monomeric intercalates has been isolated and identified by X-ray diffraction and infrared spectroscopy. Second, interslab free-radical polymerization of acrylate anions has been successfully initiated using potassium persulfate. In cobalt- or manganese-based LDHs, one-step polymerization has been observed, leading directly to a material containing polyacrylate intercalate.

  16. High-valent iron and manganese complexes of corrole and porphyrin in atom transfer and dioxygen evolving catalysis.

    PubMed

    Abu-Omar, Mahdi M

    2011-04-14

    Manganese(V) imido complexes of 5,10,15-tris(pentafluorophenyl)corrole (H(3)tpfc) can be prepared by the reaction of Mn(III)(tpfc) and organic nitrene generated from either photolytic or thermal activation of organic azides. The terminal imido complexes of manganese(V) were among the first structurally characterized examples of Mn(V) terminal imido complexes in the literature. They feature a short Mn≡N triple bond and a nearly linear M[triple bond, length as m-dash]N-C angle. The ground state of (tpfc)Mn(V)(NAr) is singlet. Contrary to expectations, arylimido complexes of manganese(V) were stable to moisture and did not undergo [NR] group transfer to olefins. Manganese(V) imido corrole with an activated tosyl imido ligand was prepared from iodoimine (ArINTs) and manganese(III) corrole. The resulting complex (tpfc)Mn(NTs) is paramagnetic (S = 1), hydrolyzes to (tpfc)Mn(O) in the presence of water, abstracts hydrogen atoms from benzylic C-H bonds, and catalyzes aziridination of alkenes. Mechanistic studies on the aziridination and hydrogen atom transfer reactions are reviewed. This perspective also describes the reaction chemistry of the heme enzyme chlorite dismutase, the mechanism by which dioxygen is formed on a single-metal site, and recent advances in functional modelling of this enzyme. We also compare the reactivity of water-soluble iron versus manganese porphyrins towards the chlorite anion.

  17. 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

  18. Integrated pyrolucite fluidized bed-membrane hybrid process for improved iron and manganese control in drinking water.

    PubMed

    Dashtban Kenari, Seyedeh Laleh; Barbeau, Benoit

    2017-04-15

    Newly developed ceramic membrane technologies offer numerous advantages over the conventional polymeric membranes. This work proposes a new configuration, an integrated pyrolucite fluidized bed (PFB)-ceramic MF/UF hybrid process, for improved iron and manganese control in drinking water. A pilot-scale study was undertaken to evaluate the performance of this process with respect to iron and manganese control as well as membrane fouling. In addition, the fouling of commercially available ceramic membranes in conventional preoxidation-MF/UF process was compared with the hybrid process configuration. In this regard, a series of experiments were conducted under different influent water quality and operating conditions. Fouling mechanisms and reversibility were analyzed using blocking law and resistance-in-series models. The results evidenced that the flux rate and the concentration of calcium and humic acids in the feed water have a substantial impact on the filtration behavior of both membranes. The model for constant flux compressible cake formation well described the rise in transmembrane pressure. The compressibility of the filter cake substantially increased in the presence of 2 mg/L humic acids. The presence of calcium ions caused significant aggregation of manganese dioxide and humic acid which severely impacted the extent of membrane fouling. The PFB pretreatment properly alleviated membrane fouling by removing more than 75% and 95% of iron and manganese, respectively.

  19. Sorption of Ferric Iron from Ferrioxamine B to Synthetic and Biogenic Layer Type Manganese Oxides

    NASA Astrophysics Data System (ADS)

    Duckworth, O.; John, B.; Sposito, G.

    2006-12-01

    Siderophores are biogenic chelating agents produced in terrestrial and marine environments to increase the bioavailablity of ferric iron. Recent work has suggested that both aqueous and solid-phase Mn(III) may affect siderophore-mediated iron transport, but no information appears to be available about the effect of solid-phase Mn(IV). To probe the effects of predominantly Mn(IV) oxides, we studied the sorption reaction of ferrioxamine B [Fe(III)HDFOB+, an Fe(III) chelate of the trihydroxamate siderophore desferrioxamine B (DFOB)] with two synthetic birnessites [layer type Mn(III, IV) oxides] and a biogenic birnessite produced by Pseudomonas putida MnB1. We found that all of these predominantly Mn(IV) oxides greatly reduced the aqueous concentration of Fe(III)HDFOB+ over at pH 8. After 72 hours equilibration time, the sorption behavior for the synthetic birnessites could be accurately described by a Langmuir isotherm; for the biogenic oxide, a Freundlich isotherm was best utilized to model the sorption data. To study the molecular nature of the interaction between the Fe(III)HDFOB+ complex and the oxide surface, Fe K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy was employed. Analysis of the EXAFS spectra indicated that Fe(III) associated with the Mn(IV) oxides is not complexed by DFOB as in solution, but instead Fe(III) is specifically adsorbed to into the mineral structure at multiple sites with no evidence of DFOB complexation, thus indicating that the Mn(IV) oxides displaced Fe(III) from the siderophore complex. These results indicate that manganese oxides, including biominerals, may strongly sequester iron from soluble ferric complexes and thus may play a significant role in the biogeochemical cycling of iron in marine and terrestrial environments.

  20. The relationship between body iron stores and blood and urine cadmium concentrations in US never-smoking, non-pregnant women aged 20-49 years

    SciTech Connect

    Gallagher, Carolyn M.; Chen, John J.; Kovach, John S.

    2011-07-15

    Background: Cadmium is a ubiquitous environmental pollutant associated with increased risk of leading causes of mortality and morbidity in women, including breast cancer and osteoporosis. Iron deficiency increases absorption of dietary cadmium, rendering women, who tend to have lower iron stores than men, more susceptible to cadmium uptake. We used body iron, a measure that incorporates both serum ferritin and soluble transferrin receptor, as recommended by the World Health Organization, to evaluate the relationships between iron status and urine and blood cadmium. Methods: Serum ferritin, soluble transferrin receptor, urine and blood cadmium values in never-smoking, non-pregnant, non-lactating, non-menopausal women aged 20-49 years (n=599) were obtained from the 2003-2008 National Health and Nutrition Examination Surveys. Body iron was calculated from serum ferritin and soluble transferrin receptor, and iron deficiency defined as body iron <0 mg/kg. Robust linear regression was used to evaluate the relationships between body iron and blood and urine cadmium, adjusted for age, race, poverty, body mass index, and parity. Results: Per incremental (mg/kg) increase in body iron, urine cadmium decreased by 0.003 {mu}g/g creatinine and blood cadmium decreased by 0.014 {mu}g/L. Iron deficiency was associated with 0.044 {mu}g/g creatinine greater urine cadmium (95% CI=0.020, 0.069) and 0.162 {mu}g/L greater blood cadmium (95% CI=0.132, 0.193). Conclusions: Iron deficiency is a risk factor for increased blood and urine cadmium among never-smoking, pre-menopausal, non-pregnant US women, independent of age, race, poverty, body mass index and parity. Expanding programs to detect and correct iron deficiency among non-pregnant women merits consideration as a potential means to reduce the risk of cadmium associated diseases. - Highlights: {yields} Body iron was calculated from serum ferritin and soluble transferrin receptor. {yields} Body iron was inversely associated with blood

  1. 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.

  2. 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, ν7a = 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

  3. Metals, Oxidative Stress and Neurodegeneration: A focus on Iron, Manganese and Mercury

    PubMed Central

    Farina, Marcelo; Avila, Daiana Silva; da Rocha, João Batista Teixeira

    2013-01-01

    Essential metals are crucial for the maintenance of cell homeostasis. Among the 23 elements that have known physiological functions in humans, 12 are metals, including iron (Fe) and manganese (Mn). Nevertheless, excessive exposure to these metals may lead to pathological conditions, including neurodegeneration. Similarly, exposure to metals that do not have known biological functions, such as mercury (Hg), also present great health concerns. This reviews focuses on the neurodegenerative mechanisms and effects of Fe, Mn and Hg. Oxidative stress (OS), particularly in mitochondria, is a common feature of Fe, Mn and Hg toxicity. However, the primary molecular targets triggering OS are distinct. Free cationic iron is a potent pro-oxidant and can initiate a set of reactions that form extremely reactive products, such as OH•. Mn can oxidize dopamine (DA), generating reactive species and also affect mitochondrial function, leading to accumulation of metabolites and culminating with OS. Cationic Hg forms have strong affinity for nucleophiles, such as –SH and –SeH. Therefore, they target critical thiol- and selenol-molecules with antioxidant properties. Finally, we address the main sources of exposure to these metals, their transport mechanisms into the brain, and therapeutic modalities to mitigate their neurotoxic effects. PMID:23266600

  4. A theoretical and experimental study of calcium, iron, zinc, cadmium, and sodium ions absorption by aspartame.

    PubMed

    Mahnam, Karim; Raisi, Fatame

    2017-03-01

    Aspartame (L-Aspartyl-L-phenylalanine methyl ester) is a sweet dipeptide used in some foods and beverages. Experimental studies show that aspartame causes osteoporosis and some illnesses, which are similar to those of copper and calcium deficiency. This raises the issue that aspartame in food may interact with cations and excrete them from the body. This study aimed to study aspartame interaction with calcium, zinc, iron, sodium, and cadmium ions via molecular dynamics simulation (MD) and spectroscopy. Following a 480-ns molecular dynamics simulation, it became clear that the aspartame is able to sequester Fe(2+), Ca(2+), Cd(2+), and Zn(2+) ions for a long time. Complexation led to increasing UV-Vis absorption spectra and emission spectra of the complexes. This study suggests a potential risk of cationic absorption of aspartame. This study suggests that purification of cadmium-polluted water by aspartame needs a more general risk assessment.

  5. Concentrations of strontium, barium, cadmium, copper, zinc, manganese, chromium, antimony, selenium and lead in the equine liver and kidneys.

    PubMed

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

    2014-01-01

    The concentrations of specific elements in the equine liver and kidneys are of practical relevance since horses are not only food-producing animals, but also partially serve as an indicator for the environmental pollution, as the basic feed includes plants like grass, grain and fruits. In this study, the concentrations of strontium (Sr), barium (Ba), cadmium (Cd), copper (Cu), zinc (Zn), manganese (Mn), chromium (Cr), antimony (Sb), selenium (Se) and lead (Pb) were measured in the liver, renal cortex and renal medulla of 21 horses (8 male; 13 female; aged between 5 months-28 years), using inductively coupled plasma mass spectrometry. Comparable Cu and Zn concentrations were detected in the liver and renal cortex, while approximately 50% lower concentrations were measured in the renal medulla. The lowest Sr, Cd and Se, but the highest Mn, Sb and Pb concentrations were measured in the liver. The Ba concentrations were comparable in the renal cortex and medulla, but lower in the liver of the horses. Gender-related differences were observed for Cd, Mn and Cr, with higher Cd concentrations in the liver, but lower Mn concentrations in the renal cortex and lower Cr concentrations in the renal medulla of female horses. Age-related differences were detected for most measured elements, however, the animal number per age-group was only low. In conclusion, the present study provides important reference data for the storage of Sr, Ba, Cd, Cu, Zn, Mn, Cr, Sb, Se and Pb in the liver and kidneys of horses, which are of practical relevance for an evaluation of the exposure of horses to these elements, either via feed or the environment.

  6. Arabidopsis thaliana nicotianamine synthase 4 is required for proper response to iron deficiency and to cadmium exposure.

    PubMed

    Koen, Emmanuel; Besson-Bard, Angélique; Duc, Céline; Astier, Jérémy; Gravot, Antoine; Richaud, Pierre; Lamotte, Olivier; Boucherez, Jossia; Gaymard, Frédéric; Wendehenne, David

    2013-08-01

    The nicotianamine synthase (NAS) enzymes catalyze the formation of nicotianamine (NA), a non-proteinogenic amino acid involved in iron homeostasis. We undertook the functional characterization of AtNAS4, the fourth member of the Arabidopsis thaliana NAS gene family. A mutant carrying a T-DNA insertion in AtNAS4 (atnas4), as well as lines overexpressing AtNAS4 both in the atnas4 and the wild-type genetic backgrounds, were used to decipher the role of AtNAS4 in NA synthesis, iron homeostasis and the plant response to iron deficiency or cadmium supply. We showed that AtNAS4 is an important source for NA. Whereas atnas4 had normal growth in iron-sufficient medium, it displayed a reduced accumulation of ferritins and exhibited a hypersensitivity to iron deficiency. This phenotype was rescued in the complemented lines. Under iron deficiency, atnas4 displayed a lower expression of the iron uptake-related genes IRT1 and FRO2 as well as a reduced ferric reductase activity. Atnas4 plants also showed an enhanced sensitivity to cadmium while the transgenic plants overexpressing AtNAS4 were more tolerant. Collectively, our data, together with recent studies, support the hypothesis that AtNAS4 displays an important role in iron distribution and is required for proper response to iron deficiency and to cadmium supply.

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

    PubMed

    Stolley, H; Kersting, M; Droese, W

    1981-04-01

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

  8. Manganese oxide shuttling in pre-GOE oceans - evidence from molybdenum and iron isotopes

    NASA Astrophysics Data System (ADS)

    Kurzweil, Florian; Wille, Martin; Gantert, Niklas; Beukes, Nicolas J.; Schoenberg, Ronny

    2016-10-01

    The local occurrence of oxygen-rich shallow marine water environments has been suggested to significantly predate atmospheric oxygenation, which occurred during the Great Oxidation Event (GOE) ca. 2.4 billion years ago. However, the potential influence of such 'oxygen oases' on the mobility, distribution and isotopic composition of redox sensitive elements remains poorly understood. Here, we provide new molybdenum and iron isotopic data from shallow marine carbonate and silicate iron formations of the Koegas Subgroup, South Africa, that confirm local ocean redox stratification prior to the GOE. Mn concentrations correlate negatively with both δ98 Mo and δ56 Fe values, which highlights the substantial role of particulate manganese for the cycling of Mo and Fe in the Paleoproterozoic oceans. Based on these trends we propose that pore water molybdate was recharged (1) by the diffusional transport of seawater molybdate with high δ98 Mo and (2) by the re-liberation of adsorbed molybdate with low δ98 Mo during Mn oxide dissolution within the sediment. The relative contribution of isotopically light Mo is highest close to a Mn chemocline, where the flux of Mn oxides is largest, causing the negative correlation of Mn concentrations and δ98 Mo values in the Koegas sediments. The negative correlation between δ56 Fe values and Mn concentrations is likely related to Fe isotope fractionation during Fe(II) oxidation by Mn oxides, resulting in lower δ56 Fe values in the uppermost water column close to a Mn chemocline. We argue that the preservation of these signals within Paleoproterozoic sediments implies the existence of vertically extended chemoclines with a smoother gradient, probably as a result of low atmospheric oxygen concentrations. Furthermore, we suggest that abiotic oxidation of Fe(II) by a Mn oxide particle shuttle might have promoted the deposition of the Koegas iron formations.

  9. Levels and predictors of airborne and internal exposure to manganese and iron among welders.

    PubMed

    Pesch, Beate; Weiss, Tobias; Kendzia, Benjamin; Henry, Jana; Lehnert, Martin; Lotz, Anne; Heinze, Evelyn; Käfferlein, Heiko Udo; Van Gelder, Rainer; Berges, Markus; Hahn, Jens-Uwe; Mattenklott, Markus; Punkenburg, Ewald; Hartwig, Andrea; Brüning, Thomas

    2012-01-01

    We investigated airborne and internal exposure to manganese (Mn) and iron (Fe) among welders. Personal sampling of welding fumes was carried out in 241 welders during a shift. Metals were determined by inductively coupled plasma mass spectrometry. Mn in blood (MnB) was analyzed by graphite furnace atom absorption spectrometry. Determinants of exposure levels were estimated with multiple regression models. Respirable Mn was measured with a median of 62 (inter-quartile range (IQR) 8.4-320) μg/m(3) and correlated with Fe (r=0.92, 95% CI 0.90-0.94). Inhalable Mn was measured with similar concentrations (IQR 10-340 μg/m(3)). About 70% of the variance of Mn and Fe could be explained, mainly by the welding process. Ventilation decreased exposure to Fe and Mn significantly. Median concentrations of MnB and serum ferritin (SF) were 10.30 μg/l (IQR 8.33-13.15 μg/l) and 131 μg/l (IQR 76-240 μg/l), respectively. Few welders were presented with low iron stores, and MnB and SF were not correlated (r=0.07, 95% CI -0.05 to 0.20). Regression models revealed a significant association of the parent metal with MnB and SF, but a low fraction of variance was explained by exposure-related factors. Mn is mainly respirable in welding fumes. Airborne Mn and Fe influenced MnB and SF, respectively, in welders. This indicates an effect on the biological regulation of both metals. Mn and Fe were strongly correlated, whereas MnB and SF were not, likely due to higher iron stores among welders.

  10. In vitro preparation of iron-substituted human manganese superoxide dismutase: possible toxic properties for mitochondria.

    PubMed

    Yamakura, Fumiyuki; Kobayashi, Kazuo; Furukawa, Satoshi; Suzuki, Yasunori

    2007-08-01

    We prepared an iron-substituted form of recombinant human manganese superoxide dismutase (MnSOD) by using guanidine hydrochloride for the first time as a model of iron-misincorporated MnSOD, the formation of which has been reported by M. Yang et al. upon disruption of mitochondrial metal homeostasis in yeast (Yang et al. 2006, EMBO J. 25, 1775-1783). The iron-substituted enzyme contained 0.79 g atoms of Fe/mol of subunits and had a specific activity of 80 units/mg protein/g atom of Fe/mol of subunit, which was less than 3% of the activity of the purified MnSOD. Fe-substituted MnSOD (Fe-MnSOD) showed the same absorption spectrum as that of bacterial Fe-MnSODs reported, a similar pH-dependent change of the enzymatic activity, and a similar electron paramagnetic resonance spectrum. Fe-MnSOD showed more thermal stability than native MnSOD. The Fe-substituted enzyme showed a hydrogen-peroxide-mediated radical-generating activity, which was monitored by a cation radical of 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) formation similar to that of Cu,ZnSOD, but native human MnSOD and FeSOD showed no radical-generation ability. This evidence suggests that a substitution of Mn to Fe in human MnSOD in mitochondria may produce a disadvantage for oxidative stress in three ways: loss of the enzymatic activity, increase of stability, and gain of radical-generating ability.

  11. The role of manganese and copper in the eutectoid transformation of spheroidal graphite cast iron

    SciTech Connect

    Lacaze, J.; Boudot, A.; Gerval, V.; Oquab, D.; Santos, H.

    1997-10-01

    The decomposition of austenite to ferrite plus graphite or to pearlite in spheroidal graphite (SG) cast iron is known to depend on a number of factors among which are the nodule count, the cooling rate, and the alloying additions (Si, Mn, Cu, etc.). This study was undertaken in order to deepen the understanding of the effect of alloying with Mn and/or Cu on the eutectoid reaction. For this purpose, differential thermal analyses (DTAs) were carried out in which samples were subjected to a short homogenization treatment designed to smooth out the microsegregations originating from the solidification step. The effect of various additions of copper and manganese and of the cooling rate on the temperature of the onset of the stable and metastable eutectoid reactions was investigated. The experimental results can be explained if the appropriate reference temperature is used. The cooling rate affects the temperature of the onset of the ferrite plus graphite growth in the same way as for the eutectic reaction, with a measured undercooling that can be extrapolated to a zero value when the cooling rate is zero. The growth undercooling of pearlite had values that were in agreement with similar data obtained on silicon steels. The detrimental effect of Mn on the growth kinetics of ferrite during the decomposition of austenite in the stable system is explained in terms of the driving force for diffusion of carbon through the ferrite ring around the graphite nodules. Finally, it is found that copper can have a pearlite promoter role only when combined with a low addition of manganese.

  12. Cadmium

    Integrated Risk Information System (IRIS)

    Cadmium ; CASRN 7440 - 43 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effects

  13. 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

    2012-12-10

    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.

  14. Cadmium, iron, lead and mercury bioaccumulation in abu mullet, Liza abu, different tissues from Karoun and Karkheh rivers, Khozestan, Iran.

    PubMed

    Askary Sary, Abolfazl; Beheshti, Mahboubeh

    2012-02-01

    Lead, mercury, cadmium and iron concentration in following tissues: muscle, liver and gill of Liza abu in Karoun and Kharkheh were measured. Karoun and Kharkheh are important rivers in Iran. Significant variation in metal values were evaluated using Student's t test at p < 0.05. Result showed that maximum concentration of metals were recorded in gill tissues. Iron concentration was higher than lead, cadmium and mercury in different organs (p < 0.05). The level of metals Cd, Hg, Fe in different tissues of Karoun river was higher than Karkheh river (p < 0.05). Metals level in different tissue were upper than WHO standard.

  15. The effect of induced anoxia and reoxygenation on benthic fluxes of organic carbon, phosphate, iron, and manganese.

    PubMed

    Skoog, Annelie C; Arias-Esquivel, Victor A

    2009-11-15

    Eutrophication causes seasonally anoxic bottom waters in coastal environments, but we lack information on effects of onset of anoxia and subsequent reoxygenation on benthic fluxes of redox-sensitive minerals and associated organic carbon (OC). As the first study, we determined the effect of inducing anoxia and subsequently restoring oxic conditions in mesocosms with surface sediment and water from a coastal environment. These concentration changes were compared with those in an oxygenated control. We determined water column concentrations of dissolved organic carbon (DOC), particulate organic carbon (POC), iron, manganese, and phosphate. Benthic fluxes of DOC, POC, and iron increased at the onset of anoxia in oxygen-depleted treatments. DOC and iron concentrations increased concomitantly towards maxima, which may have indicated reductive dissolution of FeOOH and release of associated OC. The subsequent concomitant concentration decreases may have been the result of coprecipitation of OC with iron-containing minerals. In contrast, the phosphate-concentration increase occurred several days after the onset of anoxia and the manganese concentration was not affected by the onset of anoxia. Restoring oxic conditions resulted in a decrease in DOC, POC, and phosphate concentrations, which may indicate coprecipitation of OC with phosphate-containing minerals. The high DOC fluxes at the onset of anoxia indicate that redox oscillations may be important in OC degradation. Further, our results indicate a close coupling between OC cycling and dissolution/precipitation of iron-containing minerals in intermittently anoxic sediments.

  16. Geochemistry and Microbial Communities in Iron- and Manganese-Enriched Cold Groundwater Biofiltration Units

    NASA Astrophysics Data System (ADS)

    Chang, W.; Dangeti, S.; Roshani, B.; McBeth, J. M.

    2015-12-01

    Exploring how to enhance the microbially mediated oxidization of iron (Fe) and manganese (Mn) in natural and engineered environments in cold climates requires an understanding of the interactive relationships between the geochemistry of cold groundwater and Fe- and Mn-oxidizing bacteria. This study precisely measured geochemical and microbial communities in a scaled-up biofiltration system using synchrotron-based X-ray Absorption Near-Edge Spectroscopy (XANES) analyses coupled with next-generation sequencing (Illumina Miseq). Two pilot-scale biofiltration columns for Fe (Filter 1) and Mn (Filter 2) were connected in series and installed at the Langham Water Treatment Plant in Saskatoon, Canada. The groundwater temperature ranged from 4 to 8 °C. The pilot-scale study showed that successful treatment (99% removal) of both Fe and Mn was achieved in the biofilters. However, the Mn removal was significantly retarded for four months, likely due to the slow growth of Mn-oxidizing bacteria (MnOB) in Filter 2. The removal of Mn was accelerated once the redox potential in Filter 2 exceeded +300 mV. At that point, the XANES analyses showed that the oxidization states of Mn in Filter 2 were mainly +3 and +4, confirming that Mn oxidization had occurred. Geochemical analyses (PHREEQCi) also indicated changed geochemical conditions that favoured the formation of Mn-oxides during biofiltration. Next-generation sequencing analyses indicated the enrichment of iron-oxidizing bacteria (FeOB), including Gallionella sp. and Sideroxydans sp., in Filter 1. There were high read numbers for MnOB relatives, including Pseudomonas sp., Hydrogenophaga sp., Bdellovibrio sp., and Leptothrix sp., in Filter 2. Furthermore, the addition of anthracite (coal-based filter media) positively affected the growth MnOB and enhanced Mn oxidization. The evidence obtained in this study provides insight into how Mn oxidization can be accelerated in cold groundwater treatment systems.

  17. 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.

    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.

  18. Theoretical technique for predicting the cumulative impact of iron and manganese oxidation in streams receiving discharge from coal mines

    USGS Publications Warehouse

    Bobay, Keith E.

    1986-01-01

    Two U.S. Geological Survey computer programs are modified and linked to predict the cumulative impact of iron and manganese oxidation in coal-mine discharge water on the dissolved chemical quality of a receiving stream. The coupled programs calculate the changes in dissolved iron, dissolved manganese, and dissolved oxygen concentrations; alkalinity; and, pH of surface water downstream from the point of discharge. First, the one-dimensional, stead-state stream, water quality program uses a dissolved oxygen model to calculate the changes in concentration of elements as a function of the chemical reaction rates and time-of-travel. Second, a program (PHREEQE) combining pH, reduction-oxidation potential, and equilibrium equations uses an aqueous-ion association model to determine the saturation indices and to calculate pH; it then mixes the discharge with a receiving stream. The kinetic processes of the first program dominate the system, whereas the equilibrium thermodynamics of the second define the limits of the reactions. A comprehensive test of the technique was not possible because a complete set of data was unavailable. However, the cumulative impact of representative discharges from several coal mines on stream quality in a small watershed in southwestern Indiana was simulated to illustrate the operation of the technique and to determine its sensitivity to changes in physical, chemical, and kinetic parameters. Mine discharges averaged 2 cu ft/sec, with a pH of 6.0, and concentrations of 7.0 mg/L dissolved iron, 4.0 mg/L dissolved manganese, and 8.08 mg/L dissolved oxygen. The receiving stream discharge was 2 cu ft/sec, with a pH of 7.0, and concentrations of 0.1 mg/L dissolved iron, 0.1 mg/L dissolved manganese, and 8.70 mg/L dissolved oxygen. Results of the simulations indicated the following cumulative impact on the receiving stream from five discharges as compared with the effect from one discharge: 0.30 unit decrease in pH, 1.82 mg/L increase in dissolved

  19. 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 CH₄ (AOM) either via the reduction of sulphate (SO₄(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 NH₄(+) 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.

  20. Manganese doped iron oxide theranostic nanoparticles for combined T1 magnetic resonance imaging and photothermal therapy.

    PubMed

    Zhang, Mengxin; Cao, Yuhua; Wang, Lina; Ma, Yufei; Tu, Xiaolong; Zhang, Zhijun

    2015-03-04

    Photothermal therapy (PTT) is a noninvasive and convenient way to ablate tumor tissues. Integrating PTT with imaging technique could precisely identify the location and the size of tumor regions, thereby significantly improving the therapeutic efficacy. Magnetic resonance imaging (MRI) is widely used in clinical diagnosis due to its superb spatial resolution and real-time monitoring feature. In our work, we developed a theranostic nanoplatform based on manganese doped iron oxide (MnIO) nanoparticles modified with denatured bovine serum albumin (MnIO-dBSA). The in vitro experiment revealed that the MnIO nanoparticles exhibited T1-weighted MRI capability (r1 = 8.24 mM(-1) s(-1), r2/r1 = 2.18) and good photothermal effect under near-infrared laser irradiation (808 nm). Using 4T1 tumor-bearing mice as an animal model, we further demonstrated that the MnIO-dBSA composites could significantly increase T1 MRI signal intensity at the tumor site (about two times) and effectively ablate tumor tissues with photoirradiation. Taken together, this work demonstrates the great potential of the MnIO nanoparticles as an ideal theranostic platform for efficient tumor MR imaging and photothermal therapy.

  1. Synthesis, crystal structure and magnetism of iron(III) and manganese(III) dipicolinates with pyridinemethanols

    NASA Astrophysics Data System (ADS)

    Uhrecký, Róbert; Pavlik, Ján; Růžičková, Zdeňka; Dlháň, Ľubor; Koman, Marian; Boča, Roman; Moncoľ, Ján

    2014-11-01

    Four ionic iron(III) and manganese(III) dipicolinato complexes of the formula (2-pymeH) [FeIII(dipic)2]ṡ[FeIII(H2O)2Cl(dipic)]ṡ2H2O, (3-pymeH)[MnIII(dipic)2]ṡ1.5H2O, (4-pymeH)[FeIII(dipic)2]ṡ2H2O and (4-pymeH)[MnIII(dipic)2]ṡ2H2O, where H2dipic = pyridine-2,6-dicarboxylic acid, 2-pyme = 2-pyridinemethanol, 3-pyme = 3-pyridinemethanol, 4-pyme = 4-pyridinemethanol, have been prepared and characterized by the single-crystal X-ray structure analysis, infrared spectroscopy and magnetic measurements. The magnetic data were fitted to a zero-field splitting model revealing a slight magnetic anisotropy for Mn(III) systems. The molecular field correction was consistently formulated and included in the analysis for both, magnetic susceptibility and magnetization data.

  2. 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.

  3. Chromium Mobilization by Microbially-Driven Iron and Manganese Redox Cycling

    NASA Astrophysics Data System (ADS)

    Garcia Arredondo, M.; Hausladen, D.; Ying, S.; Fendorf, S. E.

    2014-12-01

    Chromium, a naturally occurring contaminant, poses a significant threat to California groundwater quality when ultramafic rocks weather leaving Cr-enriched serpentine soils. Benign and of limited solubility, Cr(III) can oxidize into soluble and carcinogenic Cr(VI). Under most environmental conditions, Mn-oxides are the principal oxidant of Cr(III). Here we investigate Cr(III) oxidation by both abiotically synthesized birnessite and biogenically produced Mn-oxides. Further, we explore chromium dynamics within artificial soil aggregates composed of Cr(OH)3- and Cr0.25Fe0.75(OH)3-coated quartz grains surrounded by aerated solute flow. Abiotic aggregates contained synthetic birnessite, while biotic aggregates were inoculated with Leptothrix cholodnii, a manganese-oxidizing bacterium, and Shewanella putrefaciens, an iron-reducing bacterium. Results show aqueous Cr(VI) concentrations scaling with Cr-mineral solubility. When Leptothrix sp.-inoculated Cr(III),Fe(III)-aggregates are supplied with aqueous Mn(II), Mn-oxides precipitate in the aerobic aggregate. Cr(VI) production occurs similar to that via synthetic birnessite. With the addition of Shewanella sp., coupled biotic and abiotic processes occur causing the reduction, and subsequent immobilization, of chromium by microbial metabolites (e.g., Fe(II)). This study shows the importance of microbial community composition on chromium dynamics within diffusion-limited zones, and suggests the potential for biological immobilization of Cr even in the presence of Mn-oxidizing bacteria.

  4. Role of cobalt, iron, lead, manganese, mercury, platinum, selenium, and titanium in carcinogenesis.

    PubMed Central

    Kazantzis, G

    1981-01-01

    The possible carcinogenicity of cobalt, iron, lead, manganese, mercury, platinum, selenium, and titanium is reviewed, taking into account epidemiological data, the results of animal experimental studies, data on mutagenic effects and on other in vitro test systems. Of the great variety of occupations where exposure to one of these metals may occur, only haematite mining has been clearly shown to involve an increased human cancer risk. While the possibility that haematite might in some way act as a carcinogen has to be taken into consideration it is more likely that other carcinogens are responsible. Certain platinum coordination complexes are used in cancer chemotherapy, are mutagenic, and likely to be carcinogenic. Cobalt, its oxide and sulfide, certain lead salts, one organomanganese, and one organotitanium compound have been shown to have a limited carcinogenic effect in experimental animal studies, and except for titanium appear to be mutagenic. Certain mercury compounds are mutagenic but none have been shown to be carcinogenic. The presently available data are inadequate to assess the possible carcinogenicity of selenium compounds, but a few observations suggest that selenium may suppress the effect of other carcinogens administered to experimental animals and may even be associated with lower cancer mortality rates in man. Epidemiological observations are essential for the assessment of a human cancer risk, but the difficulty in collecting past exposure data in occupational groups and the complexity of multiple occupational exposures with changes over time, limits the usefulness of retrospective epidemiological studies. PMID:7023929

  5. A low-cost iron-cadmium redox flow battery for large-scale energy storage

    NASA Astrophysics Data System (ADS)

    Zeng, Y. K.; Zhao, T. S.; Zhou, X. L.; Wei, L.; Jiang, H. R.

    2016-10-01

    The redox flow battery (RFB) is one of the most promising large-scale energy storage technologies that offer a potential solution to the intermittency of renewable sources such as wind and solar. The prerequisite for widespread utilization of RFBs is low capital cost. In this work, an iron-cadmium redox flow battery (Fe/Cd RFB) with a premixed iron and cadmium solution is developed and tested. It is demonstrated that the coulombic efficiency and energy efficiency of the Fe/Cd RFB reach 98.7% and 80.2% at 120 mA cm-2, respectively. The Fe/Cd RFB exhibits stable efficiencies with capacity retention of 99.87% per cycle during the cycle test. Moreover, the Fe/Cd RFB is estimated to have a low capital cost of 108 kWh-1 for 8-h energy storage. Intrinsically low-cost active materials, high cell performance and excellent capacity retention equip the Fe/Cd RFB to be a promising solution for large-scale energy storage systems.

  6. Manganese Health Research Program (MHRP)

    DTIC Science & Technology

    2008-01-01

    Via the Olfactory Nerve David Dorman, CPI Magnetic Resonance Imaging (MRI) of Manganese Accumulation in the Rat Brain Associated with Iron ...Magnetic Resonance Imaging (MRI) of Manganese Accumulation in the Rat Brain Associated with Iron - Deficiency and Supplementation PRINCIPAL...TITLE AND SUBTITLE Magnetic Resonance Imaging (MRI) of Manganese Accumulation in the Rat Brain Associated with Iron -Deficiency and Supplementation

  7. Synthesis, characterization and chemical properties of 1-((E)-2-pyridinylmethylidene)semicarbazone manganese(II) and iron(II) complexes

    NASA Astrophysics Data System (ADS)

    Garbelini, Ellery Regina; Martin, Maria da Graça M. B.; Back, Davi Fernando; Evans, David John; Müller-Santos, Marcelo; Ribeiro, Ronny Rocha; Lang, Ernesto Schulz; Nunes, Fábio Souza

    2012-01-01

    Manganese(II) perchlorate and iron(II) chloride react with 2-formylpyridine semicarbazone (HCSpy) in boiling ethanol to produce [Mn II(HSCpy) 2](ClO 4) 2·C 2H 5OH and [Fe IICl(HSCpy)]Cl. The distorted octahedral manganese complex crystallizes in the triclinic system with space group P(-1). The ligand HSCpy is tridentate and is coordinated through two nitrogen and one oxygen atoms. Comparison of the bond distances with analogous transition metal complexes that have the same geometry revealed longer bonds for the manganese derivative, an outcome that correlates well with the radius of the metal ions. The iron(II) ion is tetracoordinated to one semicarbazone and one chloride. Mass spectrometry, conductivity measurements, Mössbauer, UV-VIS, FTIR and elemental analysis were all in accordance with the proposed composition and the plausible geometry of [FeCl(HSCpy)]Cl. Mass spectrometry unequivocally detected the presence of the [FeCl(HSCpy)] + ion with a m/ z of 254.97 and intensity of 2 × 10 5.

  8. A Superoxide Dismutase Capable of Functioning with Iron or Manganese Promotes the Resistance of Staphylococcus aureus to Calprotectin and Nutritional Immunity

    PubMed Central

    Tarrant, Emma; Skaar, Eric P.

    2017-01-01

    Staphylococcus aureus is a devastating mammalian pathogen for which the development of new therapeutic approaches is urgently needed due to the prevalence of antibiotic resistance. During infection pathogens must overcome the dual threats of host-imposed manganese starvation, termed nutritional immunity, and the oxidative burst of immune cells. These defenses function synergistically, as host-imposed manganese starvation reduces activity of the manganese-dependent enzyme superoxide dismutase (SOD). S. aureus expresses two SODs, denoted SodA and SodM. While all staphylococci possess SodA, SodM is unique to S. aureus, but the advantage that S. aureus gains by expressing two apparently manganese-dependent SODs is unknown. Surprisingly, loss of both SODs renders S. aureus more sensitive to host-imposed manganese starvation, suggesting a role for these proteins in overcoming nutritional immunity. In this study, we have elucidated the respective contributions of SodA and SodM to resisting oxidative stress and nutritional immunity. These analyses revealed that SodA is important for resisting oxidative stress and for disease development when manganese is abundant, while SodM is important under manganese-deplete conditions. In vitro analysis demonstrated that SodA is strictly manganese-dependent whereas SodM is in fact cambialistic, possessing equal enzymatic activity when loaded with manganese or iron. Cumulatively, these studies provide a mechanistic rationale for the acquisition of a second superoxide dismutase by S. aureus and demonstrate an important contribution of cambialistic SODs to bacterial pathogenesis. Furthermore, they also suggest a new mechanism for resisting manganese starvation, namely populating manganese-utilizing enzymes with iron. PMID:28103306

  9. Substitution of manganese and iron into hydroxyapatite: Core/shell nanoparticles

    SciTech Connect

    Pon-On, Weeraphat; Meejoo, Siwaporn; Tang, I.-Ming

    2008-08-04

    The bioceramics, hydroxyapatite (HAP), is a material which is biocompatible to the human body and is well suited to be used in hyperthermia applications for the treatment of bone cancer. We investigate the substitution of iron and manganese into the hydroxyapatite to yield ceramics having the empirical formula Ca{sub 9.4}Fe{sub 0.4}Mn{sub 0.2}(PO{sub 4}){sub 6}(OH){sub 2}. The samples were prepared by the co-precipitation method. The formation of the nanocrystallites in the HAP structure as the heating temperatures were raised to obtain a glass-ceramic system are confirmed by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED) and electron spin resonance (ESR). TEM images show the core/shell structure of the nanoparticles, with the core being formed by the ferrites and the shell by the hydroxyapatite. The ED patterns indicate the nanoparticles formed at 500 deg. C have an amorphous structure while the nanoparticles formed at 1000 deg. C are crystalline. ESR spectroscopy indicated that the Fe{sup 3+} ions have a g-factor of 4.23 and the Mn{sup 2+} ions have a g-factor of 2.01. The values of the parameters in the spin Hamiltonian which describes the interaction between the transition metal ions and the Ca{sup 2+} ions, indicate that the Mn{sup 2+} ion substitute into the Ca{sup 2+} sites which are ninefold coordinated, i.e., the Ca(1) sites.

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

    PubMed

    Mohan, Dinesh; Chander, Subhash

    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 degrees C were 34.22, 25.84, and 11.90 mg/g for Fe(II), Mn(II), and Fe(III), respectively. Adsorption of Fe(2+) (24.70 mg/g at 10 degrees C and 46.46 mg/g at 40 degrees C) increased with increased temperature, while Mn(2+) adsorption (28.11 mg/g at 10 degrees C and 7.70 mg/g at 40 degrees C) decreased with increased temperature.

  11. The Vacuolar Manganese Transporter MTP8 Determines Tolerance to Iron Deficiency-Induced Chlorosis in Arabidopsis.

    PubMed

    Eroglu, Seckin; Meier, Bastian; von Wirén, Nicolaus; Peiter, Edgar

    2016-02-01

    Iron (Fe) deficiency is a widespread nutritional disorder on calcareous soils. To identify genes involved in the Fe deficiency response, Arabidopsis (Arabidopsis thaliana) transfer DNA insertion lines were screened on a high-pH medium with low Fe availability. This approach identified METAL TOLERANCE PROTEIN8 (MTP8), a member of the Cation Diffusion Facilitator family, as a critical determinant for the tolerance to Fe deficiency-induced chlorosis, also on soil substrate. Subcellular localization to the tonoplast, complementation of a manganese (Mn)-sensitive Saccharomyces cerevisiae yeast strain, and Mn sensitivity of mtp8 knockout mutants characterized the protein as a vacuolar Mn transporter suitable to prevent plant cells from Mn toxicity. MTP8 expression was strongly induced on low-Fe as well as high-Mn medium, which were both strictly dependent on the transcription factor FIT, indicating that high-Mn stress induces Fe deficiency. mtp8 mutants were only hypersensitive to Fe deficiency when Mn was present in the medium, which further suggested an Mn-specific role of MTP8 during Fe limitation. Under those conditions, mtp8 mutants not only translocated more Mn to the shoot than did wild-type plants but suffered in particular from critically low Fe concentrations and, hence, Fe chlorosis, although the transcriptional Fe deficiency response was up-regulated more strongly in mtp8. The diminished uptake of Fe from Mn-containing low-Fe medium by mtp8 mutants was caused by an impaired ability to boost the ferric chelate reductase activity, which is an essential process in Fe acquisition. These findings provide a mechanistic explanation for the long-known interference of Mn in Fe nutrition and define the molecular processes by which plants alleviate this antagonism.

  12. Oxidation and competitive retention of arsenic between iron- and manganese oxides

    NASA Astrophysics Data System (ADS)

    Ying, Samantha C.; Kocar, Benjamin D.; Fendorf, Scott

    2012-11-01

    Manganese (Mn) and iron (Fe) oxides are ubiquitous solids in terrestrial systems that have high sorptive capacities for many trace metals, including arsenic (As). Although numerous studies have characterized the effects of As adsorption onto Fe and Mn oxides individually, the fate of arsenic within mixed systems representative of natural environments has not been completely resolved. Here, we examine oxidation and competitive retention of As on goethite and birnessite using a Donnan reactor, where each oxide is isolated by a semi-permeable membrane through which arsenic can migrate. To initiate the Donnan reactor experiments, As(III) was simultaneously added to both chambers. Arsenic(III) injected into the birnessite chamber is rapidly oxidized to As(V) and then slowly redistributes across both chambers, while that added to the goethite chamber undergoes rapid adsorption; the adsorbed As(III) on goethite subsequently undergoes desorption and diffusion into the birnessite chamber followed by oxidation to As(V). With increased reaction time, As(V) is generated and preferentially partitioned onto goethite due to higher adsorption affinity compared to birnessite. Furthermore, the dissolved concentration of As(V) is controlled by the adsorption capacity of the goethite surface, which when saturated, leads to increased aqueous As concentrations; despite an increase in As(V) loading on birnessite with increasing initial As(III) concentration, the resulting aqueous As(V) concentration increase appreciably once the goethite surface is saturated. Our findings show that Mn oxides in soils act as a temporary sorbent of As, but operate primarily as strong oxidants responsible for transformation of As(III) to As(V), which can then strongly adsorb on the surrounding Fe oxide matrix.

  13. Phytoavailability and fractions of iron and manganese in calcareous soil amended with composted urban wastes.

    PubMed

    Gallardo-Lara, Francisco; Azcón, Mariano; Polo, Alfredo

    2006-01-01

    Little is known about the effects of applying composted urban wastes on the phytoavailability and distribution of iron (Fe) and manganese (Mn) among chemical fractions in soil. In order to study this concern several experiments in pots containing calcareous soil were carried out. The received treatments by adding separately two rates (20 and 80 Mg ha-1) of municipal solid waste (MSW) compost and/or municipal solid waste and sewage sludge (MSW-SS) co-compost. The cropping sequence was a lettuce crop followed by a barley crop. It was observed that treatments amended with composted urban wastes tended to promote slight increases in lettuce yield compared to the control. The highest Fe levels in lettuce were found when higher rates of MSW-SS co-compost were applied; these values were significant compared to those obtained in the other treatments. In all cases, the application of organic materials increased the concentration and uptake of Mn in lettuce compared to the control; however, these increases were significant only when higher rates of MSW compost were applied. The organic amendments had beneficial delayed effects on barley yields, showing, in most cases, significant increases compared to the control. In this context, treatments with MSW compost were found to be more effective than the equivalent treatments amended with MSW-SS co-compost. Compared to the control, composted urban wastes increased Fe concentration in straw and rachis, and decreased Fe concentration in barley grain. Similarly, a decreased concentration of Mn in the dry matter of barley crop grown in soils treated with composted urban wastes was observed.

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

    SciTech Connect

    Lin, Chin Yik; Abdullah, Mohd. Harun; Musta, Baba; Praveena, Sarva Mangala; Aris, Ahmad Zaharin

    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. Copper, chromium, manganese, iron, nickel, and zinc levels in biological samples of diabetes mellitus patients.

    PubMed

    Kazi, Tasneem Gul; Afridi, Hassan Imran; Kazi, Naveed; Jamali, Mohammad Khan; Arain, Mohammad Bilal; Jalbani, Nussarat; Kandhro, Ghulam Abbas

    2008-04-01

    There is accumulating evidence that the metabolism of several trace elements is altered in diabetes mellitus and that these nutrients might have specific roles in the pathogenesis and progress of this disease. The aim of present study was to compare the level of essential trace elements, chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), and zinc (Zn) in biological samples (whole blood, urine, and scalp hair) of patients who have diabetes mellitus type 2 (n = 257), with those of nondiabetic control subjects (n = 166), age ranged (45-75) of both genders. The element concentrations were measured by means of an atomic absorption spectrophotometer after microwave-induced acid digestion. The validity and accuracy was checked by conventional wet-acid-digestion method and using certified reference materials. The overall recoveries of all elements were found in the range of (97.60-99.49%) of certified values. The results of this study showed that the mean values of Zn, Mn, and Cr were significantly reduced in blood and scalp-hair samples of diabetic patients as compared to control subjects of both genders (p < 0.001). The urinary levels of these elements were found to be higher in the diabetic patients than in the age-matched healthy controls. In contrast, high mean values of Cu and Fe were detected in scalp hair and blood from patients versus the nondiabetic subjects, but the differences found in blood samples was not significant (p < 0.05). These results are consistent with those obtained in other studies, confirming that deficiency and efficiency of some essential trace metals may play a role in the development of diabetes mellitus.

  16. Isolation and reconstitution of iron- and manganese-containing superoxide dismutases from Bacteroides thetaiotaomicron.

    PubMed Central

    Pennington, C D; Gregory, E M

    1986-01-01

    Superoxide dismutase (SOD) from extracts of anaerobically maintained Bacteroides thetaiotaomicron was a dimer of equally sized 23,000-molecular-weight monomers joined noncovalently. A preparation with a specific activity of 1,200 U/mg contained 1.1 g-atom of Fe, 0.6 g-atom of Zn, and less than 0.05 g-atom of Mn per mol of dimer. The apoprotein, prepared by dialysis of iron-SOD in 5 M guanidinium chloride-20 mM 8-hydroxyquinoline, had no superoxide-scavenging activity when renatured without exogenous metal. Enzymatic activity was restored to the denatured apoprotein by dialysis against either 1 mM Fe(NH4)2 or 1 mM MnCl2 in 20 mM Tris (pH 7.0). The Fe-reconstituted enzyme and the native enzyme were inhibited approximately 50% by 0.2 mM NaN3, whereas the Mn-reconstituted enzyme was inhibited 60% by 10 mM NaN3. Aeration of the anaerobic cells resulted in a fourfold induction of an azide-resistant SOD. The enzyme (43,000 molecular weight) isolated from aerated cells was a dimer of equally sized subunits. The metal content was 1.0 g-atom of Mn, 0.55 g-atom of Fe, and 0.3 g-atom of Zn per mol of dimer. Enzymatic activity of the denatured apoprotein from this enzyme was also restored on addition of either iron or manganese. The constitutive Fe-SOD and the O2-induced Mn-SOD, tested alone and in combination, migrated identically on acrylamide gels, had similar amino acid compositions, and had alanine as the sole N-terminal amino acid. These data are consistent with the synthesis of a single apoprotein in either anaerobically maintained or oxygenated cells. We have observed a similar phenomenon with SOD from Bacteroides fragilis (E. M. Gregory, Arch. Biochem. Biophys. 238:83-89, 1985). PMID:3700336

  17. The HvNramp5 Transporter Mediates Uptake of Cadmium and Manganese, But Not Iron.

    PubMed

    Wu, Dezhi; Yamaji, Naoki; Yamane, Miki; Kashino-Fujii, Miho; Sato, Kazuhiro; Feng Ma, Jian

    2016-11-01

    The Natural Resistance Associated Macrophage Protein (Nramp) represents a transporter family for metal ions in all organisms. Here, we functionally characterized a member of Nramp family in barley (Hordeum vulgare), HvNramp5. This member showed different expression patterns, transport substrate specificity, and cellular localization from its close homolog in rice (Oryza sativa), OsNramp5, although HvNramp5 was also localized to the plasma membrane. HvNramp5 was mainly expressed in the roots and its expression was not affected by Cd and deficiency of Zn, Cu, and Mn, but slightly up-regulated by Fe deficiency. Spatial expression analysis showed that the expression of HvNramp5 was higher in the root tips than that in the basal root regions. Furthermore, analysis with laser microdissection revealed higher expression of HvNramp5 in the outer root cell layers. HvNramp5 showed transport activity for both Mn(2+) and Cd(2+), but not for Fe(2+) when expressed in yeast. Immunostaining with a HvNramp5 antibody showed that this protein was localized in the root epidermal cells without polarity. Knockdown of HvNramp5 in barley resulted in a significant reduction in the seedling growth at low Mn supply, but this reduction was rescued at high Mn supply. The concentration of Mn and Cd, but not other metals including Cu, Zn, and Fe, was decreased in both the roots and shoots of knockdown lines compared with the wild-type barley. These results indicate that HvNramp5 is a transporter required for uptake of Mn and Cd, but not for Fe, and that barley has a distinct uptake system from rice.

  18. Interactions of cadmium compounds with endogenous iron in the intestinal tract

    SciTech Connect

    Sugawara, N.; Sugawara, C. )

    1991-02-01

    The authors previously reported that when cadmium (Cd) given orally to mice or rats, they showed a decrease of hemoglobin, or of hepatic and renal iron (Fe). The decrease may be due to the decrease of Fe uptake into the intestinal mucosa brush border membrane. In a related work, it was suggested that internalized-Cd blocks the transferrin cycle within intestinal cells. Recently, the role of ferritin in the process of intestinal Fe absorption has been evaluated. Even now, Fe absorption from the GI tract is still under discussion. In order to understand the competition of Cd with Fe further, the authors gave some Cd compounds known to be taken up in different manners into the intestinal mucosa to mice.

  19. Material and detector properties of cadmium manganese telluride (Cd1-xMnxTe) crystals grown by the modified floating-zone method

    DOE PAGES

    Hossain, A.; Gu, G. D.; Bolotnikov, A. E.; ...

    2014-12-24

    We demonstrated the material- and radiation-detection properties of cadmium manganese telluride (Cd1-xMnxTe; x=0.06), a wide-band-gap semiconductor crystal grown by the modified floating-zone method. We investigated the presence of various bulk defects, such as Te inclusions, twins, and dislocations of several as-grown indium-doped Cd1-xMnxTe crystals using different techniques, viz., IR transmission microscopy, and chemical etching. We then fabricated four planar detectors from selected CdMnTe crystals, characterized their electrical properties, and tested their performance as room-temperature X- and gamma-ray detectors. Thus, our experimental results show that CMT crystals grown by the modified floating zone method apparently are free from Te inclusions. However,more » we still need to optimize our growth parameters to attain high-resistivity, large-volume single-crystal CdMnTe.« less

  20. Manganese Research Health Project (MHRP)

    DTIC Science & Technology

    2006-01-01

    MRI) of Manganese Role of Manganese in Prion Disease Pathogenesis Accumulation in the Rat Brain Associated with Iron - Deficiency and Supplementation...Imaging (MRI) of Manganese Accumulation in the Rat Brain Associated with Iron -Deficiency and Supplementation Aschner, Michael, Ph.D. Fitsanakis, Vanessa...Aschner (2006). Determination of brain manganese and iron accumulation using magnetic resonance imaging (MRI) and atomic absorption spectroscopy. 4 2 nd

  1. Manganese: it turns iron into steel (and does so much more)

    USGS Publications Warehouse

    Cannon, William F.

    2014-01-01

    Manganese is a common ferrous metal with atomic weight of 25 and the chemical symbol Mn. It constitutes roughly 0.1 percent of the Earth’s crust, making it the 12th most abundant element. Its early uses were limited largely to pigments and oxidants in chemical processes and experiments, but the significance of manganese to human societies exploded with the development of modern steelmaking technology in the 1860s. U.S consumption of manganese is about 500,000 metric tons each year, predominantly by the steel industry. Because manganese is essential and irreplaceable in steelmaking and its global mining industry is dominated by just a few nations, it is considered one of the most critical mineral commodities for the United States.

  2. 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.

  3. Microwave digestion techniques in the sequential extraction of calcium, iron, chromium, manganese, lead, and zinc in sediments

    SciTech Connect

    Mahan, K.I.; Foderaro, T.A.; Garza, T.L.; Martinez, R.M.; Maroney, G.A.; Trivisonno, M.R.; Willging, E.M.

    1987-04-01

    The sequential extraction scheme of Tessier partitions metals in sediments into exchangeable, carbonate bound iron-manganese oxide bound, organic bound, and residual binding fractions. Extraction rate experiments using conventional and microwave heating showed that microwave heating produces results comparable to the conventional procedure. Sequential microwave extraction procedures were established from the results of the extraction rate experiments. Recoveries of total metals from NBS SRM 1645 ranged from 76% to 120% for the conventional procedure and 62% to 120% for the microwave procedure. Recoveries of total metals using the microwave and conventional techniques were reasonably comparable except for iron (62% by microwave vs. 76% by conventional). Substitution of an aqua regia/HF extraction for total/residual metals results in essentially complete recovery of metals. Precision obtained from 31 replicate samples of the California Gulch, Colorado, sediment yielded about an average 11% relative standard deviation excluding the exchangeable fraction which was more variable.

  4. Influence of biofilms on iron and manganese deposition in drinking water distribution systems.

    PubMed

    Ginige, Maneesha P; Wylie, Jason; Plumb, Jason

    2011-02-01

    Although health risk due to discoloured water is minimal, such water continues to be the source of one of the major complaints received by most water utilities in Australia. Elevated levels of iron (Fe) and/or manganese (Mn) in bulk water are associated with discoloured water incidents. The accumulation of these two elements in distribution systems is believed to be one of the main causes for such elevated levels. An investigation into the contribution of pipe wall biofilms towards Fe and Mn deposition, and discoloured water events is reported in this study. Eight laboratory-scale reactors were operated to test four different conditions in duplicate. Four reactors were exposed to low Fe (0.05 mg l(-1)) and Mn (0.02 mg l(-1)) concentrations and the remaining four were exposed to a higher (0.3 and 0.4 mg l(-1) for Fe and Mn, respectively) concentration. Two of the four reactors which received low and high Fe and Mn concentrations were chlorinated (3.0 mg l(-1) of chlorine). The biological activity (measured in terms of ATP) on the glass rings in these reactors was very low (∼1.5 ng cm(-2) ring). Higher concentrations of Fe and Mn in bulk water and active biofilms resulted in increased deposition of Fe and Mn on the glass rings. Moreover, with an increase in biological activity, an increase in Fe and Mn deposition was observed. The observations in the laboratory-scale experiments were in line with the results of field observations that were carried out using biofilm monitors. The field data additionally demonstrated the effect of seasons, where increased biofilm activities observed on pipe wall biofilms during late summer and early autumn were found to be associated with increased deposition of Fe and Mn. In contrast, during the cooler months, biofilm activities were a magnitude lower and the deposited metal concentrations were also significantly less (ie a drop of 68% for Fe and 86% for Mn). Based on the laboratory-scale investigations, detachment of pipe wall

  5. 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.

  6. Intestinal DMT1 is critical for iron absorption in the mouse but is not required for the absorption of copper or manganese.

    PubMed

    Shawki, Ali; Anthony, Sarah R; Nose, Yasuhiro; Engevik, Melinda A; Niespodzany, Eric J; Barrientos, Tomasa; Öhrvik, Helena; Worrell, Roger T; Thiele, Dennis J; Mackenzie, Bryan

    2015-10-15

    Divalent metal-ion transporter-1 (DMT1) is a widely expressed iron-preferring membrane-transport protein that serves a critical role in erythroid iron utilization. We have investigated its role in intestinal metal absorption by studying a mouse model lacking intestinal DMT1 (i.e., DMT1(int/int)). DMT1(int/int) mice exhibited a profound hypochromic-microcytic anemia, splenomegaly, and cardiomegaly. That the anemia was due to iron deficiency was demonstrated by the following observations in DMT1(int/int) mice: 1) blood iron and tissue nonheme-iron stores were depleted; 2) mRNA expression of liver hepcidin (Hamp1) was depressed; and 3) intraperitoneal iron injection corrected the anemia, and reversed the changes in blood iron, nonheme-iron stores, and hepcidin expression levels. We observed decreased total iron content in multiple tissues from DMT1(int/int) mice compared with DMT1(+/+) mice but no meaningful change in copper, manganese, or zinc. DMT1(int/int) mice absorbed (64)Cu and (54)Mn from an intragastric dose to the same extent as did DMT1(+/+) mice but the absorption of (59)Fe was virtually abolished in DMT1(int/int) mice. This study reveals a critical function for DMT1 in intestinal nonheme-iron absorption for normal growth and development. Further, this work demonstrates that intestinal DMT1 is not required for the intestinal transport of copper, manganese, or zinc.

  7. 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 μmol 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.

  8. Simultaneous determination of cadmium, iron and tin in canned foods using high-resolution continuum source graphite furnace atomic absorption spectrometry.

    PubMed

    Leao, Danilo J; Junior, Mario M S; Brandao, Geovani C; Ferreira, Sergio L C

    2016-06-01

    A method was established to simultaneously determine cadmium, iron and tin in canned-food samples using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS). The quantification step has been performed using the primary line (228.802nm) for cadmium and the adjacent secondary lines (228.725nm and 228.668nm) for iron and tin, respectively. The selected chemical modifier was an acid solution that contained a mixture of 0.1% (w/v) Pd and 0.05% (w/v) Mg. The absorbance signals were measured based on the peak area using 3 pixels for cadmium and 5 pixels for iron and tin. Under these conditions, cadmium, iron and tin have been determined in canned-food samples using the external calibration technique based on aqueous standards, where the limits of quantification were 2.10ngg(-1) for cadmium, 1.95mgkg(-1) for iron and 3.00mgkg(-1) for tin, and the characteristic masses were 1.0pg for cadmium, 0.9ng for iron and 1.1ng for tin. The precision was evaluated using two solutions of each metal ion, and the results, which were expressed as the relative standard deviation (RSD%), were 3.4-6.8%. The method accuracy for cadmium and iron was confirmed by analyzing a certified reference material of apple leaves (NIST 1515), which was supplied by NIST. However, for tin, the accuracy was confirmed by comparing the results of the proposed method and another analytical technique (inductively coupled plasma optical emission spectrometry). The proposed procedure was applied to determine cadmium, iron and tin in canned samples of peeled tomato and sardine. Eleven samples were analyzed, and the analyte concentrations were 3.57-62.9ngg(-1), 2.68-31.48mgkg(-1) and 4.06-122.0mgkg(-1) for cadmium, iron and tin, respectively. In all analyzed samples, the cadmium and tin contents were lower than the permissible maximum levels for these metals in canned foods in the Brazilian legislation.

  9. Splicing factor SR34b mutation reduces cadmium tolerance in Arabidopsis by regulating iron-regulated transporter 1 gene

    SciTech Connect

    Zhang, Wentao; Du, Bojing; Liu, Di; Qi, Xiaoting

    2014-12-12

    Highlights: • Arabidopsis splicing factor SR34b gene is cadmium-inducible. • SR34b T-DNA insertion mutant is sensitive to cadmium due to high cadmium uptake. • SR34b is a regulator of cadmium transporter IRT1 at the posttranscription level. • These results highlight the roles of splicing factors in cadmium tolerance of plant. - Abstract: Serine/arginine-rich (SR) proteins are important splicing factors. However, the biological functions of plant SR proteins remain unclear especially in abiotic stresses. Cadmium (Cd) is a non-essential element that negatively affects plant growth and development. In this study, we provided clear evidence for SR gene involved in Cd tolerance in planta. Systemic expression analysis of 17 Arabidopsis SR genes revealed that SR34b is the only SR gene upregulated by Cd, suggesting its potential roles in Arabidopsis Cd tolerance. Consistent with this, a SR34b T-DNA insertion mutant (sr34b) was moderately sensitive to Cd, which had higher Cd{sup 2+} uptake rate and accumulated Cd in greater amounts than wild-type. This was due to the altered expression of iron-regulated transporter 1 (IRT1) gene in sr34b mutant. Under normal growth conditions, IRT1 mRNAs highly accumulated in sr34b mutant, which was a result of increased stability of IRT1 mRNA. Under Cd stress, however, sr34b mutant plants had a splicing defect in IRT1 gene, thus reducing the IRT1 mRNA accumulation. Despite of this, sr34b mutant plants still constitutively expressed IRT1 proteins under Cd stress, thereby resulting in Cd stress-sensitive phenotype. We therefore propose the essential roles of SR34b in posttranscriptional regulation of IRT1 expression and identify it as a regulator of Arabidopsis Cd tolerance.

  10. Blood-brain barrier flux of aluminum, manganese, iron and other metals suspected to contribute to metal-induced neurodegeneration.

    PubMed

    Yokel, Robert A

    2006-11-01

    The etiology of many neurodegenerative diseases has been only partly attributed to acquired traits, suggesting environmental factors may also contribute. Metal dyshomeostasis causes or has been implicated in many neurodegenerative diseases. Metal flux across the blood-brain barrier (the primary route of brain metal uptake) and the choroid plexuses as well as sensory nerve metal uptake from the nasal cavity are reviewed. Transporters that have been described at the blood-brain barrier are listed to illustrate the extensive possibilities for moving substances into and out of the brain. The controversial role of aluminum in Alzheimer's disease, evidence suggesting brain aluminum uptake by transferrin-receptor mediated endocytosis and of aluminum citrate by system Xc;{-} and an organic anion transporter, and results suggesting transporter-mediated aluminum brain efflux are reviewed. The ability of manganese to produce a parkinsonism-like syndrome, evidence suggesting manganese uptake by transferrin- and non-transferrin-dependent mechanisms which may include store-operated calcium channels, and the lack of transporter-mediated manganese brain efflux, are discussed. The evidence for transferrin-dependent and independent mechanisms of brain iron uptake is presented. The copper transporters, ATP7A and ATP7B, and their roles in Menkes and Wilson's diseases, are summarized. Brain zinc uptake is facilitated by L- and D-histidine, but a transporter, if involved, has not been identified. Brain lead uptake may involve a non-energy-dependent process, store-operated calcium channels, and/or an ATP-dependent calcium pump. Methyl mercury can form a complex with L-cysteine that mimics methionine, enabling its transport by the L system. The putative roles of zinc transporters, ZnT and Zip, in regulating brain zinc are discussed. Although brain uptake mechanisms for some metals have been identified, metal efflux from the brain has received little attention, preventing integration of

  11. Cadmium, copper, iron, and zinc concentrations in kidneys of grey wolves, Canis lupus, from Alaska, Idaho, Montana (USA) and the Northwest Territories (Canada).

    PubMed

    Hoffmann, S R; Blunck, S A; Petersen, K N; Jones, E M; Koval, J C; Misek, R; Frick, J A; Cluff, H D; Sime, C A; McNay, M; Beckman, K B; Atkinson, M W; Drew, M; Collinge, M D; Bangs, E E; Harper, R G

    2010-11-01

    Cadmium, copper, iron, and zinc levels were measured in the kidneys of 115 grey wolves (Canis lupus) from Idaho, Montana and Alaska (United States), and from the Northwest Territories (Canada). No significant differences in the levels of iron or copper were observed between locations, but wolf kidneys from more northern locations had significantly higher cadmium levels (Alaska > Northwest Territories > Montana ≈ Idaho), and wolves from Alaska showed significantly higher zinc than other locations. Additionally, female wolves in Alaska had higher iron levels than males, and adult wolves in Montana had higher copper levels than subadults.

  12. Iron deficiency is associated with increased levels of blood cadmium in the Korean general population: Analysis of 2008-2009 Korean National Health and Nutrition Examination Survey data

    SciTech Connect

    Lee, Byung-Kook; Kim, Yangho

    2012-01-15

    Introduction: We present data from the Korean National Health and Nutrition Examination Survey 2008-2009 on the distribution of blood cadmium levels and their association with iron deficiency in a representative sample of the adult Korean population. Methods: Serum ferritin was categorized into three levels: low (serum ferritin <15.0 {mu}g/L), low normal (15.0-30.0 {mu}g/L for women and 15.0-50.0 for men), and normal ({>=}30.0 {mu}g/L for women and {>=}50.0 for men), and its association with blood cadmium level was assessed after adjustment for various demographic and lifestyle factors. Results: Geometric means of blood cadmium in the low serum ferritin group in women, men, and all participants were significantly higher than in the normal group. Additionally, multiple regression analysis after adjusting for various covariates showed that blood cadmium was significantly higher in the low-ferritin group in women, men, and all participants compared with the normal group. We also found an association between serum ferritin and blood cadmium among never-smoking participants. Discussion: We found, similar to other recent population-based studies, an association between iron deficiency and increased blood cadmium in men and women, independent of smoking status. The results of the present study show that iron deficiency is associated with increased levels of blood cadmium in the general population.

  13. Magnetic nanoparticles as contrast agents in biomedical imaging: recent advances in iron- and manganese-based magnetic nanoparticles.

    PubMed

    Felton, Charlette; Karmakar, Alokita; Gartia, Yashraj; Ramidi, Punnamchandar; Biris, Alexandru S; Ghosh, Anindya

    2014-05-01

    Improvements in diagnostic measures for biomedical applications have been investigated in various studies for better interpretations of biological abnormalities and several medical conditions. The use of imaging techniques, such as magnetic resonance imaging (MRI), is widespread and becoming a standard procedure for such specialized applications. A major avenue being studied in MRI is the use of magnetic nanoparticles (NPs) as contrast agents (CAs). Among various approaches, current research also incorporates use of superparamagnetic iron oxide NPs and manganese-based NPs with biocompatible coatings for improved stability and reduced biodegradation when exposed to a biological environment. In this review, recent advances with these types of magnetic NPs and their potential use as CAs in MRI are reported, as well as new insights into the selectivity and cellular transport mechanism that occurs following injection.

  14. Antibacterial activity and spectral studies of trivalent chromium, manganese, iron macrocyclic complexes derived from oxalyldihydrazide and glyoxal.

    PubMed

    Singh, D P; Kumar, Ramesh; Singh, Jitender

    2009-06-01

    A new series of complexes is synthesized by template condensation of oxalyldihydrazide and glyoxal in methanolic medium in the presence of trivalent chromium, manganese and iron salts forming complexes of the type: [M(C(8)H(8)N(8)O(4))X]X(2) where M = Cr(III), Mn(III), Fe(III) and X = Cl(-1), NO(-1)(3), CH(3)COO(-1). The complexes have been characterized with the help of elemental analyses, conductance measurements, magnetic susceptibility measurements, electronic, NMR, infrared and far infrared spectral studies. On the basis of these studies, a five coordinate square pyramidal geometry for these complexes has been proposed. The biological activities of the metal complexes were tested in vitro against a number of pathogenic bacteria and some of the complexes exhibited remarkable antibacterial activities.

  15. Conversion of syngas to light olefins over silicalite-1 supported iron and cobalt catalysts: Effects of manganese addition

    SciTech Connect

    Das, D.; Ravichandran, G.; Chakrabarty, D.K.

    1996-10-01

    As the demand for light (C2-C4) olefins, an important raw materials for a number of chemical industries, is ever increasing considerable attention is now being paid to the design of suitable catalysts with high selectivity for small chain olefins. Although Fischer-Tropsch synthesis yields a wide spectrum of products from methane to waxes it is possible to restrict the chain growth to a few carbon atoms by containing the active metal panicles inside the small pores of a suitable support like zeolite. The nature of the zeolite support also has a strong influence on the product selectivity due to secondary reactions. This paper discusses the results of syngas conversion to light olefins over iron and cobalt catalysts supported on silicalite-1. Effect of the addition of manganese which is known to improve the selectivity to light olefins is also discussed.

  16. Possibility of using a lithotrophic iron-oxidizing microbial fuel cell as a biosensor for detecting iron and manganese in water samples.

    PubMed

    Tran, Phuong Hoang Nguyen; Luong, Tha Thanh Thi; Nguyen, Thuy Thu Thi; Nguyen, Huy Quang; Duong, Hop Van; Kim, Byung Hong; Pham, Hai The

    2015-10-01

    Iron-oxidizing bacterial consortia can be enriched in microbial fuel cells (MFCs) operated with ferrous iron as the sole electron donor. In this study, we investigated the possibility of using such lithotrophic iron-oxidizing MFC (LIO-MFC) systems as biosensors to monitor iron and manganese in water samples. When operated with anolytes containing only ferrous iron as the sole electron donor, the experimented LIO-MFCs generated electrical currents in response to the presence of Fe(2+) in the anolytes. For the concentrations of Fe(2+) in the range of 3-20 mM, a linear correlation between the current and the concentration of Fe(2+) could be achieved (r(2) = 0.98). The LIO-MFCs also responded to the presence of Mn(2+) in the anolytes but only when the Mn(2+) concentration was less than 3 mM. The presence of other metal ions such as Ni(2+) or Pb(2+) in the anolytes reduced the Fe(2+)-associated electricity generation of the LIO-MFCs at various levels. Organic compounds, when present at a non-excessive level together with Fe(2+) in the anolytes, did not affect the generation of electricity, although the compounds might serve as alternative electron donors for the anode bacteria. The performance of the LIO-MFCs was also affected to different degrees by operational parameters, including surrounding temperature, pH of the sample, buffer strength and external resistance. The results proved the potential of LIO-MFCs as biosensors sensing Fe(2+) in water samples with a significant specificity. However, the operation of the system should be in compliance with an optimal procedure to ensure reliable performance.

  17. 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

    2014-02-05

    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.

  18. Regional distributions of manganese, iron, copper, and zinc in the brains of 6-hydroxydopamine-induced parkinsonian rats.

    PubMed

    Tarohda, Tohru; Ishida, Yasushi; Kawai, Keiichi; Yamamoto, Masayoshi; Amano, Ryohei

    2005-09-01

    Time courses of changes in manganese, iron, copper, and zinc concentrations were examined in regions of the brain of a 6-hydroxydopamine (6-OHDA)-induced rat model of Parkinson's disease using inductively coupled plasma mass spectrometry (ICP-MS). The concentrations were simultaneously determined in brain section at the level of the substantia nigra 1, 3, 7, 10, 14, and 21 days after the 6-OHDA treatment and compared with those of control rats. The distributions of these elements were obtained for 18 regions of the sagittal section (1-mm thick). The ICP-MS results indicated that Mn, Fe, Cu, and Zn levels of the 6-OHDA-induced parkinsonian brain were observed to increase in all regions that lay along the dopaminergic pathway. In the substantia nigra, the increase in Mn level occurred rapidly from 3 to 7 days and preceded those in the other elements, reaching a plateau in the 6-OHDA brain. Iron and Zn levels increased gradually until 7 days and then increased rapidly from 7 to 10 days. The increase in the copper level was slightly delayed. In other regions, such as the globus pallidus, putamen, and amygdala, the levels of Mn, Fe, Cu, and Zn increased with time after 6-OHDA treatment, although the time courses of their changes were region-specific. These findings contribute to our understanding of the roles of Mn and Fe in the induction of neurological symptoms and progressive loss of dopaminergic neurons in the development of Parkinson's disease. Manganese may hold the key to disturbing cellular Fe homeostasis and accelerating Fe levels, which play the most important role in the development of Parkinson's disease.

  19. Magnetostrictive iron gallium thin films grown onto antiferromagnetic manganese nitride: Structure and magnetism

    NASA Astrophysics Data System (ADS)

    Mandru, Andrada-Oana; Corbett, Joseph P.; Richard, Andrea L.; Gallagher, James; Meng, Keng-Yuan; Ingram, David C.; Yang, Fengyuan; Smith, Arthur R.

    2016-10-01

    We report structural and magnetic properties of magnetostrictive Fe100 -xGax (x ≈ 15) alloys when deposited onto antiferromagnetic manganese nitride and non-magnetic magnesium oxide substrates. From X-ray diffraction measurements, we find that the FeGa films are single crystalline. Scanning tunneling microscopy imaging reveals that the surface morphologies are dictated by the growth temperature, composition, and substrate. The magnetic properties can be tailored by the substrate, as found by magnetic force microscopy imaging and vibrating sample magnetometry measurements. In addition to pronounced tetragonal deformations, depositing FeGa onto manganese nitride leads to the formation of stripe-like magnetic domain patterns and to the appearance of perpendicular magnetic anisotropy.

  20. Measuring brain manganese and iron accumulation in rats following 14 weeks of low-dose manganese treatment using atomic absorption spectroscopy and magnetic resonance imaging.

    PubMed

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

    2008-05-01

    Chronic exposure to manganese (Mn) may lead to a movement disorder due to preferential Mn accumulation in the globus pallidus and other basal ganglia nuclei. Iron (Fe) deficiency also results in increased brain Mn levels, as well as dysregulation of other trace metals. The relationship between Mn and Fe transport has been attributed to the fact that both metals can be transported via the same molecular mechanisms. It is not known, however, whether brain Mn distribution patterns due to increased Mn exposure vs. Fe deficiency are the same, or whether Fe supplementation would reverse or inhibit Mn deposition. To address these questions, we utilized four distinct experimental populations. Three separate groups of male Sprague-Dawley rats on different diets (control diet [MnT], Fe deficient [FeD], or Fe supplemented [FeS]) were given weekly intravenous Mn injections (3 mg Mn/kg body mass) for 14 weeks, whereas control (CN) rats were fed the control diet and received sterile saline injections. At the conclusion of the study, both blood and brain Mn and Fe levels were determined by atomic absorption spectroscopy and magnetic resonance imaging. The data indicate that changes in dietary Fe levels (either increased or decreased) result in regionally specific increases in brain Mn levels compared with CN or MnT animals. Furthermore, there was no difference in either Fe or Mn accumulation between FeS or FeD animals. These data suggest that dietary Fe manipulation, whether increased or decreased, may contribute to brain Mn deposition in populations vulnerable to increased Mn exposure.

  1. Deoxidation Equilibria of Manganese, Silicon, and Aluminum in Iron-Nickel-Chromium Melts

    NASA Astrophysics Data System (ADS)

    Dashevskii, Viktor; Aleksandrov, Aleksandr; Kanevskii, Akim; Leont'ev, Leopold

    2016-06-01

    Oxygen solution in Fe-Ni-Cr melts containing manganese, silicon, and aluminum has been thermodynamically analyzed and experimentally studied at 1873 K (1600 °C). The Fe-10 pctNi-20 pctCr and Fe-40 pctNi-15 pctCr compositions were studied as examples of the most frequently used alloys. Manganese is not a deoxidizer in these alloys, since manganese and chromium have similar affinities for oxygen. At low contents, silicon is also not a deoxidizer. However, above 0.358 pct for the Fe-10 pctNi-20 pctCr alloy and 0.261 pct for the Fe-40 pctNi-15 pctCr alloy, silicon decreases the oxygen concentration in the melts. Aluminum is an effective deoxidizer in the Fe-Ni-Cr melts. It decreases the oxygen concentration when its content is higher than 2.914 × 10-4 pct in the Fe-10 pctNi-20 pctCr alloy and 2.109 × 10-3 pct in the Fe-40 pctNi-15 pctCr alloy. Minimum oxygen concentrations are observed at aluminum contents of about 0.24 pct in the Fe-10 pctNi-20 pctCr alloy and at about 0.23 pct in the Fe-40 pctNi-15 pctCr alloy. The combined deoxidation of Fe-10 pctNi-20 pctCr and Fe-40 pctNi-15 pctCr alloys with silicon and manganese and also with aluminum and silicon was studied. The lower oxygen concentrations were reached as a result of complex deoxidation in comparison with the cases when deoxidized separately by each element at the same concentration levels.

  2. Alloys of the Fe-C-Mn system. Part 5. Special features of structure formation in white high-manganese irons

    NASA Astrophysics Data System (ADS)

    Sil'man, G. I.

    2006-03-01

    Eutectic polyhedration of the diagram is presented and special features of structure formation in high-manganese irons are analyzed. It is shown that eutectics of two kinds (alloyed ledeburite and a eutectic based on M7C3 carbides), which are in peritectic equilibrium with the melt, can be formed and be accompanied by a special austenite-carbide component having a pearlite-like structure. The quasi-eutectic and the M7C3-bearing eutectic in heat-treated high-manganese irons have a special morphology with composite arrangement of carbides in austenite. It is shown that additional alloying of manganese irons with silicon might be a promising direction. Silicon stabilizes the M7C3 carbide in its competition with cementite and ensures the possibility of fabricating austenitic mottles with such carbide. Mottles alloyed with manganese and silicon and having globular graphite, M7C3 carbides and metastable austenitic matrix are characterized by high wear resistance, good antifriction properties, and a combination of high mechanical properties.

  3. In Vivo Self-Hydroxylation of an Iron-Substituted Manganese-Dependent Extradiol Cleaving Catechol Dioxygenase

    PubMed Central

    Farquhar, Erik R.; Emerson, Joseph P.; Koehntop, Kevin D.; Reynolds, Mark F.; Trmčić, Milena

    2011-01-01

    The homoprotocatechuate 2,3-dioxygenase from Arthrobacter globiformis (MndD) catalyzes the oxidative ring cleavage reaction of its catechol substrate in an extradiol fashion. While this reactivity is more typically associated with nonheme iron enzymes, MndD exhibits an unusual specificity for manganese(II). MndD is structurally very similar to the iron(II)-dependent homoprotocatechuate 2,3-dioxygenase from Brevibacterium fuscum (HPCD), and we have previously shown that both MndD and HPCD are equally active towards substrate turnover with either Fe(II) or Mn(II) [J P Emerson, et al. (2008) Proc Natl Acad Sci USA, 105: 7347–7352]. However, expression of MndD in E. coli under aerobic conditions in the presence of excess iron results in the isolation of inactive blue-green Fe-substituted MndD (BG-FeMndD). Spectroscopic studies indicate that this form of Fe-substituted MndD contains an Fe(III) center with a bound catecholate, which is presumably generated by in vivo self-hydroxylation of a second-sphere tyrosine residue, as found for other self-hydroxylated nonheme iron oxygenases,. The absence of this modification in either the native Mn-containing MndD or Fe-containing HPCD suggests that the metal center of Fe-substituted MndD is able to bind and activate O2 in the absence of its substrate, employing a high-valent oxoiron oxidant to carry out the observed self-hydroxylation chemistry. These results demonstrate that the active site metal in MndD can support two dramatically different O2 activation pathways, further highlighting the catalytic flexibility of enzymes containing a 2-His-1-carboxylate facial triad metal binding motif. PMID:21279661

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

    DOEpatents

    Wagh, Arun S.; Jeong, Seung-Young

    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.

  5. Perinatal and Childhood Exposure to Cadmium, Manganese, and Metal Mixtures and Effects on Cognition and Behavior: A Review of Recent Literature

    PubMed Central

    Sanders, Alison P.; Henn, Birgit Claus; Wright, Robert O.

    2015-01-01

    Lead (Pb) and mercury (Hg) neurotoxicity is well established. In recent years, a growing body of evidence suggests that environmental exposure to other metals including arsenic (As), cadmium (Cd), manganese (Mn), and their mixtures also pose public health threats. In this paper we summarize the recent literature examining the relationship of prenatal and childhood environmental metal exposures with cognitive and behavioral outcomes in children. We conducted a literature search to identify epidemiologic studies that examined the relationship of Cd, Mn, and metal mixtures with children’s neurodevelopmental/cognitive and behavioral outcomes. We restricted the search to peer-reviewed studies published in English between January 2009 and March 2015. We identified a total of 31 articles of which 16, 17, and 16 studies examined the effects of Cd, Mn, or metal mixtures, respectively. Based on our review, there is suggestive evidence that prenatal/childhood Cd exposure may be associated with poorer cognition, but additional research is clearly needed. We found little evidence of behavioral effects of early life Cd exposure, and no studies found a significant relationship with attention deficit hyperactivity disorder. Studies of early life Mn exposure consistently reported negative impacts on both cognition and behavior. There is also growing evidence that co-exposure to multiple metals can result in increased neurotoxicity compared to single metal exposures, in particular during early life. Few studies have evaluated behavioral effects related to metal co-exposures. PMID:26231505

  6. Concentration of lead, cadmium, and iron in sediment dust and total suspended particles before and after initialisation of integral production in iron and steel work plant Zenica.

    PubMed

    Prcanović, Halim; Duraković, Mirnes; Beganović, Sanela

    2012-06-01

    Poor air quality is a common fact for all areas with base industry. The city of Zenica was once the metallurgical centre of Ex-Yugoslavia and is therefore highly polluted at present. Air pollution peaked in 1987 when average concentration of pollutants was extremely high (daily average concentration of SO(2) was 1800 μg m(-3)). With the beginning of the war in 1992, integral production in the steel work plant was shut down, to be re-launched in 2008. Limit values for iron do not exist, but iron has been monitored in Zenica for the past 28 years because of the presence of steel works. Concentrations of cadmium and lead have also been measured because they are very much present in polluted areas with steel works. The concentration of mentioned elements in air deposit and total suspended particles before and after integral production in the steel work plant was re-launched is the subject of this paper. Total suspended particles were measured in two locations using German standard VDI 2463 Blatt 4. Sediment dust was measured in nine locations using Bergerhoff method. The concentration of iron, lead, and cadmium was performed in the chemical laboratory of the Metallurgical Institute "Kemal Kapetanović" Zenica using standard methods. Higher concentrations of these parameters during the period of integral production clearly point to the impact of steel works on Zenica valley.

  7. 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.

  8. Distribution of cadmium, iron and zinc in millstreams of hard winter wheat (Triticum aestivum L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hard winter wheat (Triticum aestivum L.) is a major crop in the Great Plains of the United 14 States, and our previous work demonstrated that wheat genotypes vary for grain cadmium 15 accumulation, with some exceeding the CODEX standard (0.2 mg kg-1). Previous reports of 16 cadmium distribution in ...

  9. Influence and interaction of iron and cadmium on photosynthesis and antioxidative enzymes in two rice cultivars.

    PubMed

    Liu, Houjun; Zhang, Chengxin; Wang, Junmei; Zhou, Chongjun; Feng, Huan; Mahajan, Manoj D; Han, Xiaori

    2017-03-01

    In this study, a soil pot experiment was conducted to investigate the changes in photosynthesis and antioxidative enzymes in two rice varieties (Shendao 6 and Shennong 265) supplied with iron (Fe), cadmium (Cd), and Fe and Cd together. The concentrations of Fe and Cd in the soil were 0, 1.0 g Fe·kg(-1) and 0, 2.0 mg Cd·kg(-1), respectively. Photosynthetic indices and antioxidative enzyme activities were recorded at different rice growth stages. At the early stage, Cd showed a transient stimulatory effect on the photosynthetic rate of Shennong 265. For Shendao 6, however, Cd showed a transient stimulatory effect on photosynthetic rate, intercellular CO2 concentration, stomatal conductance and transpiration efficiency. In addition, the results show that Cd can also enhance the superoxide dismutase (SOD) and peroxidase (POD) activities, but reduce the malondialdehyde (MDA) and soluble protein contents in the two rice cultivars. Subsequently, Cd starts to inhibit photosynthesis and SOD activity until the ripening stage, causing the lowest photosynthetic rate and SOD activity at this stage. In contrast, Fe alleviates the Cd-induced changes at earlier or later growth stage. Notably at the later growth stage, the results show that the interaction between Fe and Cd increases the SOD and catalase (CAT) activities, while decreasing the lipid peroxidation and promoting photosynthesis. As a result, it ultimately increases the biomass. The results from this study suggest that Fe (as Fe fertilizer) is a promising alternative for agricultural use to enhance the plant development and, simultaneously, to reduce Cd toxicity in extensively polluted soils.

  10. Characterization of vanadium, manganese and iron model clusters by vibrational and optical spectroscopic methods

    NASA Astrophysics Data System (ADS)

    Ji, Wenbin

    1999-12-01

    The active ferryl intermediates in the catalytic cycles of heme proteins are subject to interactions from the proximal and distal amino acid residues which control their activities and affect the ν(FeIVO) frequency. The effects of sixth axial ligation, hydrogen bonding, and solvent induced polarization on the resonance Raman (RR) spectra of the ferryl porphyrin analogs, vanadyl (VIVO) porphyrins and their π-cation radicals, are characterized. ν(VIVO) stretching bands for (VO)TMPyP and (VO)PPIX are observed to be sensitive to the pH value of the aqueous solutions, and reveal a number of coexisting 5-coordinate (c) and 6- c vanadyl porphyrins in solution. Moreover, the ν(VIVO) bands for (VO)TMP and (VO)TPP porphyrins upshift to higher frequencies with the formation of their π-cation radicals, in agreement with that of the (VO)OEP radical. For both a1u (OEP) and a2u (TPP, TMP) type radicals, an increased positive charge on the porphyrin reduces the porphyrin --> vanadium electron donation, but enhances the oxo --> V donation. The UV-Vis absorption and RR spectroscopic studies on a series of oxo-bridged vanadium(III) and manganese (III, IV) complexes established spectrostructural correlations that are useful as monitors of the structure of vanadium(III) and manganese(III, IV) centers in biological systems. The linear and bent V-O-V dimers display distinctive RR and absorption spectra. The linear V-O-V bridge displays an intense μ-O --> V charge transfer (CT) absorption band and a strongly enhanced symmetric (νs) or antisymmetric (νas) V-O-V stretching band in RR spectra, depending upon terminal ligands. In contrast, the bent bridge shows two μ-O --> V CT bands and both νs and νas V- O-V stretches are observed in RR spectra. These νs and νas vibrations are used to indicate that the vanadium(III) oxo-bridged dimer intercalates with DNA. The Mn-O-Mn vibrational frequencies in the 400-700 cm -1 region of the oxo-bridged manganese(III, IV) dimers, trimers, and

  11. Nitric oxide contributes to cadmium toxicity in Arabidopsis by promoting cadmium accumulation in roots and by up-regulating genes related to iron uptake.

    PubMed

    Besson-Bard, Angélique; Gravot, Antoine; Richaud, Pierre; Auroy, Pascaline; Duc, Céline; Gaymard, Frédéric; Taconnat, Ludivine; Renou, Jean-Pierre; Pugin, Alain; Wendehenne, David

    2009-03-01

    Nitric oxide (NO) functions as a cell-signaling molecule in plants. In particular, a role for NO in the regulation of iron homeostasis and in the plant response to toxic metals has been proposed. Here, we investigated the synthesis and the role of NO in plants exposed to cadmium (Cd(2+)), a nonessential and toxic metal. We demonstrate that Cd(2+) induces NO synthesis in roots and leaves of Arabidopsis (Arabidopsis thaliana) seedlings. This production, which is sensitive to NO synthase inhibitors, does not involve nitrate reductase and AtNOA1 but requires IRT1, encoding a major plasma membrane transporter for iron but also Cd(2+). By analyzing the incidence of NO scavenging or inhibition of its synthesis during Cd(2+) treatment, we demonstrated that NO contributes to Cd(2+)-triggered inhibition of root growth. To understand the mechanisms underlying this process, a microarray analysis was performed in order to identify NO-modulated root genes up- and down-regulated during Cd(2+) treatment. Forty-three genes were identified encoding proteins related to iron homeostasis, proteolysis, nitrogen assimilation/metabolism, and root growth. These genes include IRT1. Investigation of the metal and ion contents in Cd(2+)-treated roots in which NO synthesis was impaired indicates that IRT1 up-regulation by NO was consistently correlated to NO's ability to promote Cd(2+) accumulation in roots. This analysis also highlights that NO is responsible for Cd(2+)-induced inhibition of root Ca(2+) accumulation. Taken together, our results suggest that NO contributes to Cd(2+) toxicity by favoring Cd(2+) versus Ca(2+) uptake and by initiating a cellular pathway resembling those activated upon iron deprivation.

  12. Nitric Oxide Contributes to Cadmium Toxicity in Arabidopsis by Promoting Cadmium Accumulation in Roots and by Up-Regulating Genes Related to Iron Uptake1[W

    PubMed Central

    Besson-Bard, Angélique; Gravot, Antoine; Richaud, Pierre; Auroy, Pascaline; Duc, Céline; Gaymard, Frédéric; Taconnat, Ludivine; Renou, Jean-Pierre; Pugin, Alain; Wendehenne, David

    2009-01-01

    Nitric oxide (NO) functions as a cell-signaling molecule in plants. In particular, a role for NO in the regulation of iron homeostasis and in the plant response to toxic metals has been proposed. Here, we investigated the synthesis and the role of NO in plants exposed to cadmium (Cd2+), a nonessential and toxic metal. We demonstrate that Cd2+ induces NO synthesis in roots and leaves of Arabidopsis (Arabidopsis thaliana) seedlings. This production, which is sensitive to NO synthase inhibitors, does not involve nitrate reductase and AtNOA1 but requires IRT1, encoding a major plasma membrane transporter for iron but also Cd2+. By analyzing the incidence of NO scavenging or inhibition of its synthesis during Cd2+ treatment, we demonstrated that NO contributes to Cd2+-triggered inhibition of root growth. To understand the mechanisms underlying this process, a microarray analysis was performed in order to identify NO-modulated root genes up- and down-regulated during Cd2+ treatment. Forty-three genes were identified encoding proteins related to iron homeostasis, proteolysis, nitrogen assimilation/metabolism, and root growth. These genes include IRT1. Investigation of the metal and ion contents in Cd2+-treated roots in which NO synthesis was impaired indicates that IRT1 up-regulation by NO was consistently correlated to NO's ability to promote Cd2+ accumulation in roots. This analysis also highlights that NO is responsible for Cd2+-induced inhibition of root Ca2+ accumulation. Taken together, our results suggest that NO contributes to Cd2+ toxicity by favoring Cd2+ versus Ca2+ uptake and by initiating a cellular pathway resembling those activated upon iron deprivation. PMID:19168643

  13. Increased manganese uptake by primary astrocyte cultures with altered iron status is mediated primarily by divalent metal transporter.

    PubMed

    Erikson, Keith M; Aschner, Michael

    2006-01-01

    Neurotoxicity due to excessive brain manganese (Mn) accumulation can occur via occupational exposure to aerosols or dusts that contain extremely high levels (>1-5 mg Mn/m(3)) of Mn, or metabolic aberrations (decreased biliary excretion). Given the putative role of astrocytes in regulating the movement of metals across the blood-brain barrier, we sought to examine the relationship between iron (Fe) status and Mn transport in astrocytes. Furthermore, our study examined the effect of Fe status on astrocytic transferrin receptor (TfR) and divalent metal transporter (DMT-1) levels and their relationship to Mn uptake, as both have been implicated as putative Mn transporters. All experiments were carried out in primary astrocyte cultures derived from neonatal rats when the cells reached full confluency (about three weeks in culture). Astrocytes were incubated for 24h in astrocyte growth medium (AGM) containing 200 microM desferroxamine (ID), 500 microM ferrous sulfate (+Fe), or no compound (CN). After 24h, 5 min (54)Mn uptake was measured and protein was harvested from parallel culture plates for DMT-1 and TfR immunoblot analysis. Both iron deprivation (ID) and iron overload (+Fe) caused significant increases (p<0.05) in (54)Mn uptake in astrocytes. TfR levels were significantly increased (p<0.05) due to ID and decreased in astrocytes exposed to +Fe treatments. As expected, DMT-1 was increased due to Fe deprivation, but surprisingly, DMT-1 levels were also increased due to +Fe treatment, albeit not to the extent noted in ID. The decreased TfR associated with +Fe treatment and the increased DMT-1 levels suggest that DMT-1 is a likely putative transporter of Mn in astrocytes.

  14. An aqueous method for the controlled manganese (Mn(2+)) substitution in superparamagnetic iron oxide nanoparticles for contrast enhancement in MRI.

    PubMed

    Ereath Beeran, Ansar; Nazeer, Shaiju S; Fernandez, Francis Boniface; Muvvala, Krishna Surendra; Wunderlich, Wilfried; Anil, Sukumaran; Vellappally, Sajith; Ramachandra Rao, M S; John, Annie; Jayasree, Ramapurath S; Varma, P R Harikrishna

    2015-02-14

    Despite the success in the use of superparamagnetic iron oxide nanoparticles (SPION) for various scientific applications, its potential in biomedical fields has not been exploited to its full potential. In this context, an in situ substitution of Mn(2+) was performed in SPION and a series of ferrite particles, MnxFe1-xFe2O4 with a varying molar ratio of Mn(2+) : Fe(2+) where 'x' varies from 0-0.75. The ferrite particles obtained were further studied in MRI contrast applications and showed appreciable enhancement in their MRI contrast properties. Manganese substituted ferrite nanocrystals (MnIOs) were synthesized using a novel, one-step aqueous co-precipitation method based on the use of a combination of sodium hydroxide and trisodium citrate (TSC). This approach yielded the formation of highly crystalline, superparamagnetic MnIOs with good control over their size and bivalent Mn ion crystal substitution. The presence of a TSC hydrophilic layer on the surface facilitated easy dispersion of the materials in an aqueous media. Primary characterizations such as structural, chemical and magnetic properties demonstrated the successful formation of manganese substituted ferrite. More significantly, the MRI relaxivity of the MnIOs improved fourfold when compared to SPION crystals imparting high potential for use as an MRI contrast agent. Further, the cytocompatibility and blood compatibility evaluations demonstrated excellent cell morphological integrity even at high concentrations of nanoparticles supporting the non-toxic nature of nanoparticles. These results open new horizons for the design of biocompatible water dispersible ferrite nanoparticles with good relaxivity properties via a versatile and easily scalable co-precipitation route.

  15. Effect of fulvic and humic acids on iron and manganese homeostasis in rats.

    PubMed

    Szabó, József; Vucskits, András Valentin; Berta, Erzsébet; Andrásofszky, Emese; Bersényi, András; Hullár, István

    2017-03-01

    The objective of this study was to investigate the effects of fulvic acid (FA) and humic acid (HA) as the two main compounds of humic substances, separately on Fe and Mn homeostasis. Seventy-two male Wistar rats were randomly divided into 9 experimental groups. The control diet (AIN-93G formula) and diets supplemented with 0.1%, 0.2%, 0.4% and 0.8% HA or FA were fed for 26 days. Fe and Mn concentrations of the large intestinal content, liver, kidney, femur and hair were determined. No significant differences were observed in the production parameters. The effects of FA and HA on iron homeostasis were significantly different. FA proved to be a good iron source, and slightly increased the iron content of liver and kidney, but - up to a dietary iron level of 52.7 mg/kg - it did not influence the efficiency of iron absorption. Above a dietary iron level of 52.7 mg/kg down-regulation of Fe absorption can be assumed. HA significantly stimulated the iron uptake and there was no down-regulation of Fe absorption up to 0.8% dietary HA supplementation level (61.5 mg Fe/kg diet). In the HA groups the iron content of the liver and kidney decreased significantly, suggesting that in spite of the better Fe absorption, the HA-Fe complex does not provide iron to the investigated organs. Neither FA nor HA supplementation influenced the Fe content of the femur and hair and slightly decreased the Mn concentration in the large intestinal content. This effect was significant (with a 22.7% Mn concentration decrease) only at the HA supplementation rate of 0.8%. Neither FA nor HA influenced significantly the Mn concentrations of the liver, kidney and femur. The Mn concentration of the hair in rats receiving FA- or HA-supplemented diets was higher than in the control rats; however, this result needs further confirmation.

  16. Trithiocyanurate complexes of iron, manganese and nickel and their anticholinesterase activity.

    PubMed

    Kopel, Pavel; Dolezal, Karel; Langer, Vratislav; Jun, Daniel; Adam, Vojtech; Kuca, Kamil; Kizek, Rene

    2014-04-08

    The complexes of Fe(II), Mn(II) and Ni(II) with a combination of a Schiff base, nitrogen-donor ligand or macrocyclic ligand and trithiocyanuric acid (ttcH3) were prepared and characterized by elemental analysis and spectroscopies. Crystal and molecular structures of the iron complex of composition [Fe(L1)](ttcH2)(ClO4)·EtOH·H2O (1), where L1 is Schiff base derived from tris(2-aminoethyl)amine and 2-pyridinecarboxaldehyde, were solved. It was found that the Schiff base is coordinated to the central iron atom by six nitrogens forming deformed octahedral arrangement, whereas trithiocyanurate(1-) anion, perchlorate and solvent molecules are not coordinated. The X-ray structure of the Schiff base sodium salt is also presented and compared with the iron complex. The anticholinesterase activity of the complexes was also studied.

  17. Impact of orchard and tillage management practices on soil leaching of atrazine, potassium, magnesium, manganese, iron, ammonium, nitrates and phosphates

    NASA Astrophysics Data System (ADS)

    Szajdak, L.; Lipiec, J.; Siczek, A.; Kotowska, U.; Nosalewicz, A.

    2009-04-01

    The experiments were carried out on an Orthic Luvisol developed from loess, over limestone, at the experimental field of Lublin Agricultural University in Felin (51o15'N, 22o35'E), Poland. The investigation deals with the problems of leaching's rate of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,2,3-triazine), potassium, magnesium, manganese, iron, ammonium, nitrates and phosphates from two management systems of soil: (i) conventionally tilled field with main tillage operations including stubble cultivator (10 cm) + harrowing followed by mouldboard ploughing to 20 cm depth, and crop rotation including selected cereals, root crops and papillionaceous crops, (ii) 35-year-old apple orchard field (100x200m) with a permanent sward that was mown in the inter-rows during the growing season. The conventionally tilled plot was under the current management practice for approximately 30 years. Field sites were close to each other (about 150 m). Core samples of 100 cm3 volume and 5 cm diameter were taken from two depths 0-10 cm and 10-20 cm, and were used to determine the soil water characteristic curve. It was observed that management practices impacted on the physic-chemical properties of soils. pH (in H2O) in tilled soil ranged from 5.80 to 5.91. However soil of orchard soil revealed higher values of pH than tilled soil and ranged from 6.36 to 6.40. The content of organic carbon for tilled soil ranged from 1.13 to 1.17%, but in orchard soil from 1.59 to 1.77%. Tillled soil showed broader range of bulk density 1.38-1.62 mg m-3, than orchard soil 1.33-134 mg m-3. The first-order kinetic reaction model was fitted to the experimental atrazine, potassium, magnesium, manganese, iron, nitrates, ammonium and phosphates leaching vs. time data. The concentrations of leached chemical compounds revealed linear curves. The correlation coefficients ranged from -0.873 to -0.993. The first-order reaction constants measured for the orchard soils were from 3.8 to 19 times higher than

  18. Alterations of serum zinc, copper, manganese, iron, calcium, and magnesium concentrations and the complexity of interelement relations in patients with obsessive-compulsive disorder.

    PubMed

    Shohag, Hasanuzzaman; Ullah, Ashik; Qusar, Shalahuddin; Rahman, Mustafizur; Hasnat, Abul

    2012-09-01

    The purpose of the present study was to evaluate the status of serum trace elements: zinc, copper, manganese, iron, calcium, and magnesium concentrations in obsessive-compulsive disorder patients. Forty-eight obsessive-compulsive disorder patients and 48 healthy volunteers were included in this study. Patients were recruited from Bangabandhu Sheikh Mujib Medical University by random sampling. Serum trace element concentrations were determined using flame atomic absorption spectroscopy (for zinc, copper, iron, calcium, and magnesium) as well as graphite furnace atomic absorption spectroscopy (for manganese). Data were analyzed using independent t test, Pearson's correlation analysis, regression analysis, and ANOVA. Statistical analysis of these data showed a definite pattern of variation among certain elements in patients with obsessive-compulsive disorder compared to controls. In patients' serum, zinc, iron, and magnesium concentrations decreased significantly (p<0.05) compared to the controls. Serum manganese and calcium concentrations were significantly higher (p<0.05) in patients compared to the controls. These data showed a definite imbalance in the interelement relations in obsessive-compulsive disorder patients compared to controls and therefore suggest a disturbance in the element homeostasis.

  19. 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-1β, IL-6, TNF-α, 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-α 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.

  20. Reference values of cadmium, arsenic and manganese in blood and factors associated with exposure levels among adult population of Rio Branco, Acre, Brazil.

    PubMed

    Freire, Carmen; Koifman, Rosalina Jorge; Fujimoto, Denys; de Oliveira Souza, Vanessa Cristina; Barbosa, Fernando; Koifman, Sergio

    2015-06-01

    This study aimed to investigate the distribution and factors influencing blood levels of Cadmium (Cd), Arsenic (As), and Manganese (Mn), and to determine their reference values in a sample of blood donors residing in Rio Branco, capital city of Acre State, Brazil. Blood samples were collected from all blood donors attending the Central Hemotherapic Unit in Rio Branco between 2010 and 2011. Among these, 1183 donors (98.9%) answered to a questionnaire on sociodemographic and lifestyle factors. Blood metal concentrations were determined by atomic spectrometry. Association between Cd, As and Mn levels and donors' characteristics was examined by linear regression analysis. Reference values were estimated as the upper limit of the 95% confidence interval of the 95th percentile of metal levels. References values were 0.87 μg L(-1) for Cd, 9.87 μg L(-1) for As, and 29.32 μg L(-1) for Mn. Reference values of Cd and As in smokers were 2.66 and 10.86 μg L(-1), respectively. Factors contributing to increase Cd levels were smoking, ethnicity (non-white), and lower education, whereas drinking tea and non-bottled water were associated with lower Cd. Lower levels of As were associated with higher household income, living near industrial facilities, working in a glass factory, a compost plant or in metal mining activities. Risk factors for Mn exposure were not identified. In general, blood Cd concentrations were in the range of exposure levels reported for other people from the general population, whereas levels of As and Mn were higher than in other non-occupationally exposed populations elsewhere.

  1. Cadmium, iron and zinc interaction and hematological parameters in rat dams and their offspring.

    PubMed

    Mikolić, Anja; Schönwald, Neala; Piasek, Martina

    2016-12-01

    The effects of cadmium (Cd) were evaluated in offspring exposed from birth until weaning (neonatal day 0-21) and 4 weeks after exposure cessation focusing on iron (Fe) and zinc (Zn) levels in organs and hematological parameters. Wistar female rats were administered 50mg Cd/L in drinking water (Cd-exposed) for 4 weeks before mating and during 3 weeks of gestation plus 3 weeks of lactation. Controls were supplied drinking water. At birth, part of Cd-exposed dams' litters was cross-fostered to control dams (CCd group) and their control litters were cross-fostered to Cd-exposed dams (CdC group). This procedure enabled to discern the effects of gestational, lactational and gestational plus lactational Cd exposure until weaning in F1 offspring. Elements were analyzed by atomic absorption spectrometry; hematological parameters manually; and histopathological changes by light microscopy. Gestational plus lactational exposure in Cd-exposed dams and their offspring increased Cd and decreased Fe levels, increased Zn in dams and decreased Zn and body weights in 11- and 21-day pups. In 21-day weanling pups, decreased red blood cell (RBC) count, hemoglobin and hematocrit values and increased reticulocytes in peripheral blood were also found with concomitant histopathological finding of extramedullary hematopoiesis in the liver. In cross-fostered pups with gestational exposure (CCd pups), Fe in the liver decreased on day 11 and Zn increased in the kidney on day 21 whereas in pups with lactational exposure (CdC pups) Zn in the brain decreased on day 11 and Fe decreased in the liver and brain on day 21. Regardless of exposure cessation at weaning, in offspring with gestational plus lactational exposure (Cd-exposed) body weights, kidney and brain Fe levels and RBC and hemoglobin remained decreased in blood until puberty. Furthermore Zn levels increased in the liver, kidney and brain. It was concluded that gestational plus lactational Cd exposure caused decreases in Fe and Zn levels

  2. Dinuclear cadmium(II), zinc(II), and manganese(II), trinuclear nickel(II), and pentanuclear copper(II) complexes with novel macrocyclic and acyclic Schiff-base ligands having enantiopure or racemic camphoric diamine components.

    PubMed

    Jiang, Jue-Chao; Chu, Zhao-Lian; Huang, Wei; Wang, Gang; You, Xiao-Zeng

    2010-07-05

    Four novel [3 + 3] Schiff-base macrocyclic ligands I-IV condensed from 2,6-diformyl-4-substituted phenols (R = CH(3) or Cl) and enantiopure or racemic camphoric diamines have been synthesized and characterized. Metal-ion complexations of these enantiopure and racemic [3 + 3] macrocyclic ligands with different cadmium(II), zinc(II), manganese(II), nickel(II), and copper(II) salts lead to the cleavage of Schiff-base C horizontal lineN double bonds and subsequent ring contraction of the macrocyclic ligands due to the size effects and the spatial restrictions of the coordination geometry of the central metals, the steric hindrance of ligands, and the counterions used. As a result, five [2 + 2] and one [1 + 2] dinuclear cadmium(II) complexes (1-6), two [2 + 2] dinuclear zinc(II) (7 and 8), and two [2 + 2] dinuclear manganese(II) (9 and 10) complexes together with one [1 + 1] trinuclear nickel(II) complex (11) and one [1 + 2] pentanuclear copper(II) complex (12), bearing enantiopure or racemic ligands, different substituent groups in the phenyl rings, and different anionic ligands (Cl(-), Br(-), OAc(-), and SCN(-)), have been obtained in which the chiral carbon atoms in the camphoric backbones are arranged in different ways (RRSS for the enantiopure ligands in 1, 2, 4, 5, and 7-10 and RSRS for the racemic ligands in 3, 6, 11, and 12). The steric hindrance effects of the methyl group bonded to one of the chiral carbon atoms of camphoric diamine units are believed to play important roles in the formation of the acyclic [1 + 1] trinuclear complex 11 and [1 + 2] dinuclear and pentanuclear complexes 6 and 12. In dinuclear cadmium(II), zinc(II), and manganese(II) complexes 1-10, the sequence of separations between the metal centers is consistent with that of the ionic radii shortened from cadmium(II) to manganese(II) to zinc(II) ions. Furthermore, UV-vis, circular dichroism, (1)H NMR, and fluorescence spectra have been used to characterize and compare the structural

  3. 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

  4. The neurotoxicity of iron, copper and manganese in Parkinson's and Wilson's diseases.

    PubMed

    Dusek, Petr; Roos, Per M; Litwin, Tomasz; Schneider, Susanne A; Flaten, Trond Peder; Aaseth, Jan

    2015-01-01

    Impaired cellular homeostasis of metals, particularly of Cu, Fe and Mn may trigger neurodegeneration through various mechanisms, notably induction of oxidative stress, promotion of α-synuclein aggregation and fibril formation, activation of microglial cells leading to inflammation and impaired production of metalloproteins. In this article we review available studies concerning Fe, Cu and Mn in Parkinson's disease and Wilson's disease. In Parkinson's disease local dysregulation of iron metabolism in the substantia nigra (SN) seems to be related to neurodegeneration with an increase in SN iron concentration, accompanied by decreased SN Cu and ceruloplasmin concentrations and increased free Cu concentrations and decreased ferroxidase activity in the cerebrospinal fluid. Available data in Wilson's disease suggest that substantial increases in CNS Cu concentrations persist for a long time during chelating treatment and that local accumulation of Fe in certain brain nuclei may occur during the course of the disease. Consequences for chelating treatment strategies are discussed.

  5. Dynamic Coupling of Iron, Manganese, and Phosphorus Behavior in Water and Sediment of Shallow Ice-Covered Eutrophic Lakes.

    PubMed

    Schroth, Andrew W; Giles, Courtney D; Isles, Peter D F; Xu, Yaoyang; Perzan, Zachary; Druschel, Gregory K

    2015-08-18

    Decreasing duration and occurrence of northern hemisphere ice cover due to recent climate warming is well-documented; however, biogeochemical dynamics underneath the ice are poorly understood. We couple time-series analyses of water column and sediment water interface (SWI) geochemistry with hydrodynamic data to develop a holistic model of iron (Fe), manganese (Mn), and phosphorus (P) behavior underneath the ice of a shallow eutrophic freshwater bay. During periods of persistent subfreezing temperatures, a highly reactive pool of dissolved and colloidal Fe, Mn, and P develops over time in surface sediments and bottom waters due to reductive dissolution of Fe/Mn(oxy)hydroxides below the SWI. Redox dynamics are driven by benthic O2 consumption, limited air-water exchange of oxygen due to ice cover, and minimal circulation. During thaw events, the concentration, distribution and size partitioning of all species changes, with the highest concentrations of P and "truly dissolved" Fe near the water column surface, and a relatively well-mixed "truly dissolved" Mn and "colloidal" Fe profile due to the influx of geochemically distinct river water and increased circulation. The partitioning and flux of trace metals and phosphorus beneath the ice is dynamic, and heavily influenced by climate-dependent physical processes that vary in both time and space.

  6. Intracellular localization and subsequent redistribution of metal transporters in a rat choroid plexus model following exposure to manganese or iron

    SciTech Connect

    Wang Xueqian; Miller, David S.

    2008-07-15

    Confocal microscopy was used to investigate the effects of manganese (Mn) and iron (Fe) exposure on the subcellular distribution of metal transporting proteins, i.e., divalent metal transporter 1 (DMT1), metal transporter protein 1 (MTP1), and transferrin receptor (TfR), in the rat intact choroid plexus which comprises the blood-cerebrospinal fluid barrier. In control tissue, DMT1 was concentrated below the apical epithelial membrane, MTP1 was diffuse within the cytosol, and TfR was distributed in vesicles around nuclei. Following Mn or Fe treatment (1 and 10 {mu}M), the distribution of DMT1 was not affected. However, MTP1 and TfR moved markedly toward the apical pole of the cells. These shifts were abolished when microtubules were disrupted. Quantitative RT-PCR and Western blot analyses revealed a significant increase in mRNA and protein levels of TfR but not DMT1 and MTP1 after Mn exposure. These results suggest that early events in the tissue response to Mn or Fe exposure involve microtubule-dependent, intracellular trafficking of MTP1 and TfR. The intracellular trafficking of metal transporters in the choroid plexus following Mn exposure may partially contribute to Mn-induced disruption in Fe homeostasis in the cerebrospinal fluid (CSF) following Mn exposure.

  7. Self-organization of recent rhythmic iron-manganese precipitations in underground mines in the Harz mountains

    NASA Astrophysics Data System (ADS)

    Dietrich, S.; Jacob, K.-H.

    1996-03-01

    A recent early diagenetic banded iron-manganese mud has been forming underground in a closed lead-zinc mine for approximately 40 years. The processes leading to the banded structure of the precipitate were studied during a period of 2 years. Therefore, 19 physical and chemical parameters were measured regularly in short intervals. The resulting time series were analysed with respect to the data sets of the monthly chemical analyses of the descendent mine water, the daily rainfall and the mineral content. The results reveal that the precipitated material undergoes internal self-organization due to interaction of redox, colloid-chemical, microbial, electrical and ripening processes, and not exclusively produced by seasonal fluctuations of material input. Thus, the primary banding of the material, caused by externally forced fluctuations of the redox conditions within the mine water, is reorganized after a short time. The finally observed bands are controlled by non-linear coupling of reaction and transport processes within the mud. A genetic model for the banded mineralization was developed and verified by numerical simulation.

  8. [Colloid effects on temporal-spatial variability of iron and manganese in shallow groundwater of garbage contaminated sites].

    PubMed

    Ma, Jie; Li, Hai-Ming; Gu, Xiao-Ming; Li, Yun

    2011-03-01

    Simulation tank experiment was conducted to elucidate the temporal-spatial variability of Iron and Manganese in leachate pollution plumes of water-bearing media. Colloid effects on transport and transformation of Fe and Mn in water-bearing media were determined emphatically. Moreover, the mechanism of Fe and Mn transport and transformation were discussed by the convection-dispersion, dissolution and transport-deposition of colloid. The results show that the total Fe and Mn in leachate pollution plume was 2.82 times and 7.51 times of infiltration leachate due to the dissolution of water-bearing medium. Along the flow direction, Fe and Mn pollution plumes spread, and the central region of plumes gradually widened by the convection-dispersion and dissolution. In the presence of colloid, the average transport velocity of Fe and Mn plumes central axis from 1.17 cm/d and 1.75 cm/d increased to 1.83 cm/d and 2.5 cm/d respectively, colloid had obvious facilitation to the migration of Fe and Mn.

  9. Elements in rice on the Swedish market: part 2. Chromium, copper, iron, manganese, platinum, rubidium, selenium and zinc.

    PubMed

    Jorhem, L; Astrand, C; Sundstrom, B; Baxter, M; Stokes, P; Lewis, J; Grawe, K P

    2008-07-01

    A survey of the levels of some essential and non-essential trace elements in different types of rice available on the Swedish retail market was carried out in 2001-03. The types of rice included long and short grain, brown, white, and parboiled white. The mean levels found were: chromium (Cr) = 0.008 mg kg(-1), copper (Cu) = 1.9 mg kg(-1), iron (Fe) = 4.7 mg kg(-1), manganese (Mn) = 16 mg kg(-1), platinum (Pt) < 0.0003 mg kg(-1), rubidium (Rb) = 3.3 mg kg(-1), selenium (Se) =0.1 mg kg(-1); and zinc (Zn) = 15 mg kg(-1). Inductively coupled plasma-mass spectrometry (ICP-MS) was used for the determination of Pt, Rb, and Se, after acid digestion. All other elements were determined using atomic absorption spectrometry (AAS) after dry ashing. Intake calculations were performed and it was concluded that rice may contribute considerably to the daily requirements of the essential elements Cu, Fe, Mn, Se, and Zn if rice consumption is high. The levels of some elements, e.g. Fe and Mn, were significantly higher in brown compared with white rice.

  10. Iron and manganese-related magnetic centers in hexagonal silicon carbide: A possible roadmap for spintronic devices

    SciTech Connect

    Machado, W. V. M.; Assali, L. V. C.; Justo, J. F.

    2015-07-28

    The electronic and magnetic properties of manganese- and iron-doped 4H-SiC were investigated by first-principles calculations, using an all electron methodology. The results on stability, spin configurations, formation and transition energies, local magnetic moments, and hyperfine parameters were compared to available theoretical and experimental data. The results indicated that transition metal impurities are energetically more favorable in lattice sites with carbon atoms as their first nearest neighbors, in both substitutional and interstitial configurations, which results from the larger electronegativity of carbon with respect to that of silicon. The analysis of the electronic properties of those impurity centers showed that they could stay in several stable charge states, depending on the Fermi energy level position within the host SiC bandgap. Additionally, by computing the p-d exchange coupling constant, which is related to a spin polarization in the SiC valence band top, we explored the possibility of achieving macroscopic magnetism in SiC. The results indicated that some centers, in both substitutional and interstitial configurations, present reasonably strong magnetic couplings to mediate macroscopic magnetism at high temperatures, which may generate spin polarized currents, leading to applications in spintronic devices.

  11. 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.

  12. [Effect of exogenous iron on accumulation and chemical forms of cadmium, and physiological characterization in different varieties of tomato].

    PubMed

    Liu, Jun; Zhou, Kun; Xu, Wei-Hong; Chen, Hui; Zhang, Ming-Zhong; Jiang, Ling; Yang, Yun; Wang, Chong-Li; Xiong, Zhi-Ting

    2013-10-01

    Pot experiments were carried out to investigate the influence of different iron (Fe) levels (0, 50, 100, 200 and 400 micromol.L-1) on the plant growth, activities of antioxidant enzymes, accumulation and chemical forms of cadmium (Cd) in tomato when exposed to Cd (10 mg.kg-1). The results showed that dry weights of fruit, roots, stem, leaf, and plant, and concentration and accumulation of Cd significantly differed between the two varieties of tomato tested. Dry weights of fruit, roots, stem, leaf, and plant increased in the presence of Fe. Activities of superoxide dismutase (SOD) of root in both varieties, and activities of catalase (CAT) of root in Yufenl09 deceased at first, and then increased with increasing levels of Fe, but activities of peroxidase (POD) of root in both varieties and activities of CAT of root in 4641 increased at first, and then reduced with increasing levels of Fe. Chemical forms of Cd in fruit of tomato were in the order of FR > FHCl > FE > FNaCl > FHAC > FW. All chemical forms of Cd obviously decreased after the application of adequate Fe compared to the control, while FHcI and FR of 4641, and the total extractable Cd, FE, FNaCl and FR of Yufenl09 increased at 400 micromol.L-1Fe treatment. Cadmium accumulations of tomato were in the order of leaf > stew > fruit > roots. Cadmium concentration in leaf, stem, roots and fruit of both varieties decreased by 7. 1% -25.3% , 30. 8% -50. 4% , 13.0% -45. 1% and 2.8% -11.7% in the presence of Fe when exposed to Cd, and the Cd concentration of fruit and Cd accumulations in plant were in the order of 4641 < Yufenl09 in the presence or absence of Fe.

  13. 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 (μg/L) for arsenic (As) and a MCL of 30 μg/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 μg/L for Mn. Recommended secondary maximum contaminant levels (SMCLs) for Fe (300 μg/L) and Mn (50 μg/L) were established primarily as

  14. 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.

  15. Novel Mode of Microbial Energy Metabolism: Organic Carbon Oxidation Coupled to Dissimilatory Reduction of Iron or Manganese

    PubMed Central

    Lovley, Derek R.; Phillips, Elizabeth J. P.

    1988-01-01

    A dissimilatory Fe(III)- and Mn(IV)-reducing microorganism was isolated from freshwater sediments of the Potomac River, Maryland. The isolate, designated GS-15, grew in defined anaerobic medium with acetate as the sole electron donor and Fe(III), Mn(IV), or nitrate as the sole electron acceptor. GS-15 oxidized acetate to carbon dioxide with the concomitant reduction of amorphic Fe(III) oxide to magnetite (Fe3O4). When Fe(III) citrate replaced amorphic Fe(III) oxide as the electron acceptor, GS-15 grew faster and reduced all of the added Fe(III) to Fe(II). GS-15 reduced a natural amorphic Fe(III) oxide but did not significantly reduce highly crystalline Fe(III) forms. Fe(III) was reduced optimally at pH 6.7 to 7 and at 30 to 35°C. Ethanol, butyrate, and propionate could also serve as electron donors for Fe(III) reduction. A variety of other organic compounds and hydrogen could not. MnO2 was completely reduced to Mn(II), which precipitated as rhodochrosite (MnCO3). Nitrate was reduced to ammonia. Oxygen could not serve as an electron acceptor, and it inhibited growth with the other electron acceptors. This is the first demonstration that microorganisms can completely oxidize organic compounds with Fe(III) or Mn(IV) as the sole electron acceptor and that oxidation of organic matter coupled to dissimilatory Fe(III) or Mn(IV) reduction can yield energy for microbial growth. GS-15 provides a model for how enzymatically catalyzed reactions can be quantitatively significant mechanisms for the reduction of iron and manganese in anaerobic environments. Images PMID:16347658

  16. 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.

  17. 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.

    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.

  18. The Vacuolar Manganese Transporter MTP8 Determines Tolerance to Iron Deficiency-Induced Chlorosis in Arabidopsis1[OPEN

    PubMed Central

    2016-01-01

    Iron (Fe) deficiency is a widespread nutritional disorder on calcareous soils. To identify genes involved in the Fe deficiency response, Arabidopsis (Arabidopsis thaliana) transfer DNA insertion lines were screened on a high-pH medium with low Fe availability. This approach identified METAL TOLERANCE PROTEIN8 (MTP8), a member of the Cation Diffusion Facilitator family, as a critical determinant for the tolerance to Fe deficiency-induced chlorosis, also on soil substrate. Subcellular localization to the tonoplast, complementation of a manganese (Mn)-sensitive Saccharomyces cerevisiae yeast strain, and Mn sensitivity of mtp8 knockout mutants characterized the protein as a vacuolar Mn transporter suitable to prevent plant cells from Mn toxicity. MTP8 expression was strongly induced on low-Fe as well as high-Mn medium, which were both strictly dependent on the transcription factor FIT, indicating that high-Mn stress induces Fe deficiency. mtp8 mutants were only hypersensitive to Fe deficiency when Mn was present in the medium, which further suggested an Mn-specific role of MTP8 during Fe limitation. Under those conditions, mtp8 mutants not only translocated more Mn to the shoot than did wild-type plants but suffered in particular from critically low Fe concentrations and, hence, Fe chlorosis, although the transcriptional Fe deficiency response was up-regulated more strongly in mtp8. The diminished uptake of Fe from Mn-containing low-Fe medium by mtp8 mutants was caused by an impaired ability to boost the ferric chelate reductase activity, which is an essential process in Fe acquisition. These findings provide a mechanistic explanation for the long-known interference of Mn in Fe nutrition and define the molecular processes by which plants alleviate this antagonism. PMID:26668333

  19. Prevalence and Relationships of Iron Deficiency Anemia with Blood Cadmium and Vitamin D Levels in Korean Women.

    PubMed

    Suh, Young Ju; Lee, Ji Eun; Lee, Dae Hyung; Yi, Hyeon Gyu; Lee, Moon Hee; Kim, Chul Soo; Nah, Jeung Weon; Kim, Soon Ki

    2016-01-01

    Anemia, iron deficiency (ID), and iron deficiency anemia (IDA) are common disorders. This study was undertaken to determine the prevalence of anemia, ID, and IDA in Korean females. We examined the associations between IDA, heavy metals in blood, vitamin D level and nutritional intakes. The study was performed using on data collected from 10,169 women (aged ≥ 10 yr), including 1,232 with anemia, 2,030 with ID, and 690 with IDA during the fifth Korea National Health and Nutrition Examination Survey (KNHANES V; 2010-2012). Prevalence and 95% confidence intervals were calculated, and path analysis was performed to identify a multivariate regression model incorporating IDA, heavy metals in blood, vitamin D level, and nutritional intakes. The overall prevalence of anemia, ID and IDA was 12.4%, 23.11%, and 7.7%, respectively. ID and IDA were more prevalent among adolescents (aged 15-18 yr; 36.5% for ID; 10.7% for IDA) and women aged 19-49 yr (32.7% for ID; 11.3% for IDA). The proposed path model showed that IDA was associated with an elevated cadmium level after adjusting for age and body mass index (β=0.46, P<0.001). Vitamin D levels were found to affect IDA negatively (β=-0.002, P<0.001). This study shows that the prevalence of anemia, ID, and IDA are relatively high in late adolescents and women of reproductive age. Path analysis showed that depressed vitamin D levels increase the risk of IDA, and that IDA increases cadmium concentrations in blood. Our findings indicate that systematic health surveillance systems including educational campaigns and well-balanced nutrition are needed to control anemia, ID, and IDA.

  20. Prevalence and Relationships of Iron Deficiency Anemia with Blood Cadmium and Vitamin D Levels in Korean Women

    PubMed Central

    2016-01-01

    Anemia, iron deficiency (ID), and iron deficiency anemia (IDA) are common disorders. This study was undertaken to determine the prevalence of anemia, ID, and IDA in Korean females. We examined the associations between IDA, heavy metals in blood, vitamin D level and nutritional intakes. The study was performed using on data collected from 10,169 women (aged ≥10 yr), including 1,232 with anemia, 2,030 with ID, and 690 with IDA during the fifth Korea National Health and Nutrition Examination Survey (KNHANES V; 2010-2012). Prevalence and 95% confidence intervals were calculated, and path analysis was performed to identify a multivariate regression model incorporating IDA, heavy metals in blood, vitamin D level, and nutritional intakes. The overall prevalence of anemia, ID and IDA was 12.4%, 23.11%, and 7.7%, respectively. ID and IDA were more prevalent among adolescents (aged 15-18 yr; 36.5% for ID; 10.7% for IDA) and women aged 19-49 yr (32.7% for ID; 11.3% for IDA). The proposed path model showed that IDA was associated with an elevated cadmium level after adjusting for age and body mass index (β=0.46, P<0.001). Vitamin D levels were found to affect IDA negatively (β=-0.002, P<0.001). This study shows that the prevalence of anemia, ID, and IDA are relatively high in late adolescents and women of reproductive age. Path analysis showed that depressed vitamin D levels increase the risk of IDA, and that IDA increases cadmium concentrations in blood. Our findings indicate that systematic health surveillance systems including educational campaigns and well-balanced nutrition are needed to control anemia, ID, and IDA. PMID:26770034

  1. Concentration of copper, iron, zinc, cadmium, lead, and nickel in boar semen and relation to the spermatozoa quality.

    PubMed

    Massányi, Peter; Trandzík, Jozef; Nad, Pavol; Koréneková, Beáta; Skalická, Magdaléna; Toman, Robert; Lukác, Norbert; Strapák, Peter; Halo, Marko; Turcan, Ján

    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(-1) and of iron 16.14 +/- 10.35 mg kg(-1). The concentration of zinc in boar semen reached an average value of 171.74 +/- 64.72 mg kg(-1) and the level of cadmium reached 0.01-0.16 mg kg(-1) with the average value of 0.05 mg kg(-1). The analysis of lead showed that the concentration of this element in boar semen was 0.02 +/- 0.03 mg kg(-1) and the average level of nickel was 0.06 +/- 0.08 mg kg(-1). The total percentage of pathological spermatozoa was 9.82 +/- 1.47%. Detail analysis determined 3.18% of separated flagellum, 2.26% knob twisted flagellum, 0.88% flagellum torso, 0.85% flagellum ball, 0.42% broken flagellum, 0.23% retention of the cytoplasmic drop, 0.14% small heads, 0.03% large heads, and 1.83% forms other of pathological changes. Correlation analysis showed significant (p < 0.05) positive correlation between copper and lead (r = 0.52). High correlation between small head and knob twisted tail (r = 0.67), small head and broken flagellum (r = 0.88) as well as between small head and total number of pathological spermatozoa (r = 0.73) was determined.

  2. 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.

  3. Iron and Manganese Pyrophosphates as Cathodes for Lithium-Ion Batteries

    SciTech Connect

    Zhou, Hui; Upreti, Shailesh; Chernova, Natasha A.; Hautier, Geoffroy; Ceder, Gerbrand; Whittingham, M. Stanley

    2015-10-15

    The mixed-metal phases, (Li{sub 2}Mn{sub 1-y}Fe{sub y}P{sub 2}O{sub 7}, 0 {le} y {le} 1), were synthesized using a 'wet method', and found to form a solid solution in the P2{sub 1}/a space group. Both thermogravimetric analysis and magnetic susceptibility measurements confirm the 2+ oxidation state for both the Mn and Fe. The electrochemical capacity improves as the Fe concentration increases, as do the intensities of the redox peaks of the cyclic voltammogram, indicating higher lithium-ion diffusivity in the iron phase. The two Li{sup +} ions in the three-dimensional tunnel structure of the pyrophosphate phase allows for the cycling of more than one lithium per redox center. Cyclic voltammograms show a second oxidation peak at 5 V and 5.3 V, indicative of the extraction of the second lithium ion, in agreement with ab initio computation predictions. Thus, electrochemical capacities exceeding 200 Ah/kg may be achieved if a stable electrolyte is found.

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

    PubMed Central

    Dučić, 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

  5. 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.

  6. Thermochemistry of perovskites in the lanthanum-strontium-manganese-iron oxide system

    NASA Astrophysics Data System (ADS)

    Marinescu, Cornelia; Vradman, Leonid; Tanasescu, Speranta; Navrotsky, Alexandra

    2015-10-01

    The enthalpies of formation from binary oxides of perovskites (ABO3) based on lanthanum strontium manganite La(Sr)MnO3 (LSM) and lanthanum strontium ferrite La(Sr)FeO3 (LSF) and mixed lanthanum strontium manganite ferrite La(Sr)Mn(Fe)O3 (LSMF) were measured by high temperature oxide melt solution calorimetry. Using iodometric titration, the oxygen content was derived. The perovskites with A-site cation deficiency have greater oxygen deficiency than the corresponding A-site stoichiometric series. Stability of LSMF decreases with increasing iron content. Increasing oxygen deficiency clearly destabilizes the perovskites. The results suggest an enthalpy of oxygen incorporation that is approximately independent of composition. 0.35La2O3 (xl, 25 °C)+Mn2O3 (xl, 25 °C)+0.3SrO (xl, 25 °C)+Fe2O3 (xl, 25 °C)+O2 (g, 25 °C)→La0.7Sr0.3Mn1-yFeyO3-δ (xl, 25 °C). (b) ∆ Hf,ox* (La0.7Sr0.3Mn1-yFeyO3-δ) .0.35 La2O3 (xl, 25 ººC) + (0.7-y+ 2δ)/2 Mn2O3 (xl, 25 ºC) + 0.3 SrO (xl, 25 ºC) + y/2Fe2O3 (xl, 25 ºC) + (0.3-2δ) MnO2 (xl, 25 ºC)→La0.7Sr0.3Mn1-yFeyO3-δ (xl, 25 ºC).

  7. Solid state 31phosphorus nuclear magnetic resonance of iron-, manganese-, and copper-containing synthetic hydroxyapatites

    NASA Technical Reports Server (NTRS)

    Sutter, B.; Taylor, R. E.; Hossner, L. R.; Ming, D. W.

    2002-01-01

    The incorporation of micronutrients into synthetic hydroxyapatite (SHA) is proposed for slow release of these nutrients to crops in the National Aeronautics and Space Administration's (NASA's) Advanced Life Support (ALS) program for Lunar or Martian outposts. Solid state 31P nuclear magnetic resonance (NMR) was utilized to examine the paramagnetic effects of Fe3+, Mn2+, and Cu2+ to determine if they were incorporated into the SHA structure. Separate Fe3+, Mn2+, and Cu2+ containing SHA materials along with a transition metal free SHA (pure-SHA) were synthesized using a precipitation method. The proximity (<1 nm) of the transition metals to the 31P nuclei of SHA were apparent when comparing the integrated 31P signal intensities of the pure-SHA (87 arbitrary units g-1) with the Fe-, Mn-, and Cu-SHA materials (37-71 arbitrary units g-1). The lower integrated 31P signal intensities of the Fe-, Mn-, and Cu-SHA materials relative to the pure-SHA suggested that Fe3+, Mn2+, and Cu2+ were incorporated in the SHA structure. Further support for Fe3+, Mn2+, and Cu2+ incorporation was demonstrated by the reduced spin-lattice relaxation constants of the Fe-, Mn-, and Cu-SHA materials (T'=0.075-0.434s) relative to pure-SHA (T1=58.4s). Inversion recovery spectra indicated that Fe3+, Mn2+, and Cu2+ were not homogeneously distributed about the 31P nuclei in the SHA structure. Extraction with diethylene-triamine-penta-acetic acid (DTPA) suggested that between 50 and 80% of the total starting metal concentrations were incorporated in the SHA structure. Iron-, Mn-, and Cu-containing SHA are potential slow release sources of Fe, Mn, and Cu in the ALS cropping system.

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

    NASA Astrophysics Data System (ADS)

    Thomas, C. A.; Bendell-Young, L. I.

    1999-06-01

    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 <0·2μm 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 characterized as: % organic matter (% LOI); reducible iron (RED Fe, iron oxides) and easily reducible manganese (ER Mn, manganese oxides). Grain size at each site was also determined. The sediment geochemical matrix, as defined by the above four parameters, was highly heterogeneous throughout the intertidal region (three-way ANOVA; P<0·0001). For RED Fe and ER Mn, this heterogeneity could be explained by either diagenetic processes (RED Fe) or by a combination of the proximity of the sample sites to the mouth of the Fraser River estuary plus diagenetic processes (ER Mn). Correlation (Spearman Rank Correlation Test (r s), of dissolved iron within the subsurface sediments with amounts of RED Fe recovered from the associated surface sediments was highly significant (r s=0·80, P<0·0001); high concentrations of RED Fe at the sediment-water interface co-occurred with high concentrations of dissolved iron, regardless of the proximity of the sample locations to riverine input. Compared with iron, the relationship between dissolved manganese and ER Mn from surface sediments was lower (r s=0·58; P<0·0008). Locations most strongly influenced by the Fraser River contained greater concentrations of ER Mn at the sediment-water interface than that which would be expected based on the contribution from diagenesis alone. Sediment grain size and organic matter were also influenced by the proximity to riverine input. Surficial sediment of sites close to the river mouth were comprised primarily of percent silt (2·0μm-50μm) whereas sites not influenced by

  9. An in vitro assessment of the interaction of cadmium selenide quantum dots with DNA, iron, and blood platelets.

    PubMed

    Dunpall, Rekha; Nejo, Adeola Ayodeji; Pullabhotla, Viswanadha Srirama Rajasekhar; Opoku, Andy R; Revaprasadu, Neerish; Shonhai, Addmore

    2012-12-01

    Cadmium selenide (CdSe) quantum dots have gained increased attention for their potential use in biomedical applications. This has raised interest in assessing their toxicity. In this study, water-soluble, cysteine-capped CdSe nanocrystals with an average size of 15 nm were prepared through a one-pot solution-based method. The CdSe nanoparticles were synthesized in batches in which the concentration of the capping agent was varied with the aim of stabilizing the quantum dot core. The effects of the CdSe quantum dots on DNA stability, aggregation of blood platelets, and reducing activity of iron were evaluated in vitro . DNA damage was observed at a concentration of 200 μg/mL of CdSe quantum dots. Furthermore, the CdSe nanocrystals exhibited high reducing power and chelating activity, suggesting that they may impair the function of haemoglobin by interacting with iron. In addition, the CdSe quantum dots promoted aggregation of blood platelets in a dose dependent manner.

  10. 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 μg 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).

  11. 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.; 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.

  12. 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 μg/mL for the MTT assay and 20 μg/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

  13. Insights into the iron-ome and manganese-ome of Δmtm1 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 Δmtm1 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 Δmtm1 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 Δmtm1 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 Δmtm1 mitochondria might be unfolded or immature. Mtm1p may import a species required for apo-Sod2p maturation, activity or stability. PMID:23598994

  14. Reactive iron and manganese in estuarine sediments of the Baltic Sea: Impacts of flocculation and redox shuttling

    NASA Astrophysics Data System (ADS)

    Jilbert, Tom; Tiihonen, Rosa; Myllykangas, Jukka-Pekka; Asmala, Eero; Hietanen, Susanna

    2016-04-01

    Iron (Fe) and manganese (Mn) play important roles in sedimentary carbon cycling in both freshwater and marine systems. Dissimilatory reduction of Fe and Mn oxides is known to be a major pathway of suboxic organic matter remineralization in surface sediments, while recent studies have shown that Fe and Mn oxides may be involved in the anaerobic oxidation of methane deeper in the sediment column (e.g., Egger et al., 2015). Estuaries are transitional environments, characterized by gradients of salinity and redox conditions which impact on the mobility of Fe and Mn. In turn, the distribution of Fe and Mn in estuarine sediments, and the role of the two metals in carbon cycling, is expected to be spatially heterogeneous. However, few studies have attempted to describe the sedimentary distribution of Fe and Mn in the context of processes occurring in the estuarine water column. In particular, salinity-driven flocculation and redox shuttling are two key processes whose relative impacts on sedimentary Fe and Mn have not been clearly demonstrated. In this study we investigated the coupled water column and sedimentary cycling of Fe and Mn along a 60km non-tidal estuarine transect in the Gulf of Finland, Baltic Sea. We show that riverine Fe entering the estuary as colloidal oxides associated with dissolved organic matter (DOM) is quickly flocculated and sedimented within 5 km of the river mouth, despite the shallow lateral salinity gradient. Sediments within this range are enriched in Fe (up to twice the regional average), principally in the form of crystalline Fe oxides as determined by sequential extractions. The high crystallinity implies relative maturity of the oxide mineralogy, likely due to sustained oxic conditions and long residence time in the river catchment. Despite the reducing conditions below the sediment-water interface, Fe is largely retained in the sediments close to the river mouth. In contrast, sedimentary Mn concentrations are highest in a deep silled

  15. The HvNramp5 Transporter Mediates Uptake of Cadmium and Manganese, But Not Iron1[OPEN

    PubMed Central

    Wu, Dezhi; Yamaji, Naoki; Yamane, Miki; Kashino-Fujii, Miho

    2016-01-01

    The Natural Resistance Associated Macrophage Protein (Nramp) represents a transporter family for metal ions in all organisms. Here, we functionally characterized a member of Nramp family in barley (Hordeum vulgare), HvNramp5. This member showed different expression patterns, transport substrate specificity, and cellular localization from its close homolog in rice (Oryza sativa), OsNramp5, although HvNramp5 was also localized to the plasma membrane. HvNramp5 was mainly expressed in the roots and its expression was not affected by Cd and deficiency of Zn, Cu, and Mn, but slightly up-regulated by Fe deficiency. Spatial expression analysis showed that the expression of HvNramp5 was higher in the root tips than that in the basal root regions. Furthermore, analysis with laser microdissection revealed higher expression of HvNramp5 in the outer root cell layers. HvNramp5 showed transport activity for both Mn2+ and Cd2+, but not for Fe2+ when expressed in yeast. Immunostaining with a HvNramp5 antibody showed that this protein was localized in the root epidermal cells without polarity. Knockdown of HvNramp5 in barley resulted in a significant reduction in the seedling growth at low Mn supply, but this reduction was rescued at high Mn supply. The concentration of Mn and Cd, but not other metals including Cu, Zn, and Fe, was decreased in both the roots and shoots of knockdown lines compared with the wild-type barley. These results indicate that HvNramp5 is a transporter required for uptake of Mn and Cd, but not for Fe, and that barley has a distinct uptake system from rice. PMID:27621428

  16. 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.

    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.

  17. Effect of chronic ethanol ingestion on the metabolism of copper, iron, manganese, selenium, and zinc in an animal model of alcoholic cardiomyopathy

    SciTech Connect

    Bogden, J.D.; Al-Rabiai, S.; Gilani, S.H.

    1984-01-01

    Alcoholic cardiomyopathy (AC) is one of the diseases caused by alcohol abuse, and there has been considerable debate about the possibility that nutritional factors may be important in the etiology of AC. In addition, there is evidence that ethanol may affect the metabolism of trace elements. The purpose of this investigation was to determine if chronic ethanol administration produces changes in the metabolism of the essential metals copper, iron, manganese, zinc, and selenium using an animal model of AC. Eighteen male Sprague-Dawley rats were divided into three groups; an ad libitum control group (AL), a pair-fed control group (PF), and an ethanol-dosed group (ETOH). The latter group received gradually increasing concentrations (5-25%) of ethanol in the drinking water for 15 wk. Food intake was monitored and urine and feces collected for a 4-d period during the study to determine ethanol effects on trace-element balance. Growth of both the PF and ETOH animals was inhibited. Ethanol produced substantial increases in liver manganese and decreases in liver copper and zinc. Metal concentrations in heart and concentrations in other tissues studied (spleen, testes, brain, bone, kidney, and muscle) did not differ significantly among the groups, except for testes selenium and kidney zinc. Reduced food intake and ethanol ingestion were associated with a reduced percentage of ingested selenium excreted in the urine. Deficiencies of copper, iron, manganese, selenium, and zinc in myocardial tissue are not likely to be involved in the pathogenesis of AC in the rat. 38 references, 1 figure, 4 tables.

  18. Splicing factor SR34b mutation reduces cadmium tolerance in Arabidopsis by regulating iron-regulated transporter 1 gene.

    PubMed

    Zhang, Wentao; Du, Bojing; Liu, Di; Qi, Xiaoting

    2014-12-12

    Serine/arginine-rich (SR) proteins are important splicing factors. However, the biological functions of plant SR proteins remain unclear especially in abiotic stresses. Cadmium (Cd) is a non-essential element that negatively affects plant growth and development. In this study, we provided clear evidence for SR gene involved in Cd tolerance in planta. Systemic expression analysis of 17 Arabidopsis SR genes revealed that SR34b is the only SR gene upregulated by Cd, suggesting its potential roles in Arabidopsis Cd tolerance. Consistent with this, a SR34b T-DNA insertion mutant (sr34b) was moderately sensitive to Cd, which had higher Cd(2+) uptake rate and accumulated Cd in greater amounts than wild-type. This was due to the altered expression of iron-regulated transporter 1 (IRT1) gene in sr34b mutant. Under normal growth conditions, IRT1 mRNAs highly accumulated in sr34b mutant, which was a result of increased stability of IRT1 mRNA. Under Cd stress, however, sr34b mutant plants had a splicing defect in IRT1 gene, thus reducing the IRT1 mRNA accumulation. Despite of this, sr34b mutant plants still constitutively expressed IRT1 proteins under Cd stress, thereby resulting in Cd stress-sensitive phenotype. We therefore propose the essential roles of SR34b in posttranscriptional regulation of IRT1 expression and identify it as a regulator of Arabidopsis Cd tolerance.

  19. Expression profiling reveals functionally redundant multiple-copy genes related to zinc, iron and cadmium responses in Brassica rapa.

    PubMed

    Li, Jimeng; Liu, Bo; Cheng, Feng; Wang, Xiaowu; Aarts, Mark G M; Wu, Jian

    2014-07-01

    Genes underlying environmental adaptability tend to be over-retained in polyploid plant species. Zinc deficiency (ZnD) and iron deficiency (FeD), excess Zn (ZnE) and cadmium exposure (CdE) are major environmental problems for crop cultivation, but little is known about the differential expression of duplicated genes upon these stress conditions. Applying Tag-Seq technology to leaves of Brassica rapa grown under FeD, ZnD, ZnE or CdE conditions, with normal conditions as a control, we examined global gene expression changes and compared the expression patterns of multiple paralogs. We identified 812, 543, 331 and 447 differentially expressed genes under FeD, ZnD, ZnE and CdE conditions, respectively, in B. rapa leaves. Genes involved in regulatory networks centered on the transcription factors bHLH038 or bHLH100 were differentially expressed under (ZnE-induced) FeD. Further analysis revealed that genes associated with Zn, Fe and Cd responses tended to be over-retained in the B. rapa genome. Most of these multiple-copy genes showed the same direction of expression change under stress conditions. We conclude that the duplicated genes involved in trace element responses in B. rapa are functionally redundant, making the regulatory network more complex in B. rapa than in Arabidopsis thaliana.

  20. Mineral resource of the month: manganese

    USGS Publications Warehouse

    Corathers, Lisa A.

    2012-01-01

    Manganese is a silver-colored metal resembling iron and often found in conjunction with iron. The earliest-known human use of manganese compounds was in the Stone Age, when early humans used manganese dioxide as pigments in cave paintings. In ancient Rome and Egypt, people started using it to color or remove the color from glass - a practice that continued to modern times. Today, manganese is predominantly used in metallurgical applications as an alloying addition, particularly in steel and cast iron production. Steel and cast iron together provide the largest market for manganese (historically 85 to 90 percent), but it is also alloyed with nonferrous metals such as aluminum and copper. Its importance to steel cannot be overstated, as almost all types of steel contain manganese and could not exist without it.

  1. Concentration of copper, iron, zinc, cadmium, lead, and nickel in bull and ram semen and relation to the occurrence of pathological spermatozoa.

    PubMed

    Massányi, P; Trandzik, J; Nad, P; Koreneková, B; Skalická, M; Toman, R; Lukac, N; Halo, M; Strapak, P

    2004-01-01

    In this study the concentration of copper, iron, zinc, cadmium, lead, and nickel in bull and ram semen and relation of these metals to spermatozoa morphology was investigated. Analysis by atomic absorption spectrophotometry showed that copper concentration was significantly higher (p<0.0001) in ram semen in comparison with bull semen. The zinc concentration was higher in bull semen in comparison with ram semen. The iron and cadmium concentrations in the semen were similar. Higher concentration of lead was found in ram semen. Higher levels of nickel were found in ram semen in comparison with bulls. In bull semen 11.79+/-4.88% of pathological spermatozoa was found. Higher occurrence of pathological spermatozoa was in ram semen (17.17+/-3.76) in comparison with the semen of bulls. Separated tail, tail torso, and knob twisted tail were the most frequent forms of pathological spermatozoa in both species. Correlation analysis in bulls showed high positive relation between iron and zinc (r = 0.72), nickel and separated tail (r = 0.76), separated tail and tail torso (r = 0.71), tail torso and total number of pathological spermatozoa (r=0.72), and between tail ball and total number of pathological spermatozoa (r = 0.78). In rams high positive correlation between cadmium and lead (r=0.98), nickel and separated tail (r=0.77), separated tail and total number of pathological spermatozoa (r=0.69), knob twisted tail and retention of cytoplasmic drop (r=0.78), and between knob twisted tail and other pathological spermatozoa (r = 0.71) was found. High negative correlation in ram semen was observed between copper and nickel (r=0.71), copper and separated tail (r=0.70), and between iron and tail torso (r=0.67). The results suggest that the studied metals have a direct effect on spermatozoa quality.

  2. Cadmium toxicity-induced proline accumulation is coupled to iron depletion.

    PubMed

    Sharmila, P; Kumari, P Kusuma; Singh, Kavita; Prasad, N V S R K; Pardha-Saradhi, P

    2017-03-01

    Investigations were conducted to elucidate the key factor behind Cd(2+)-toxicity-induced proline accumulation in Indian mustard (Brassica juncea) by raising seedlings, independently in distilled water (DW) and mineral growth medium (MGM) in the presence of 0-500 μM CdCl2. Invariably, Cd(2+)-induced toxicity, measured in terms of growth, was significantly more prominent in seedlings raised in DW than those raised in MGM. Cd(2+) brought about a significant reduction in growth and photosystem II activity with a concomitant increase in proline levels, in a concentration-dependent manner. Interestingly, the level of iron in shoots of seedlings decreased proportionately with increase in Cd(2+) toxicity. Cd(2+)-promoted proline accumulation was significantly higher in seedlings raised in DW than those raised in MGM. Depletion of essential cations (viz. Ca(2+), Mg(2+), K(+), and Fe(2+)) from MGM one at a time revealed that depletion of Fe(2+) leads to maximal proline accumulation under Cd(2+) toxicity. Interestingly, proline level in seedlings raised under Cd(2+) toxicity in DW supplemented with Fe(2+) was similar to that recorded in seedlings raised in MGM. Our results convincingly demonstrated that Cd(2+)-induced iron deficiency promotes proline accumulation.

  3. Bog Manganese Ore: A Resource for High Manganese Steel Making

    NASA Astrophysics Data System (ADS)

    Pani, Swatirupa; Singh, Saroj K.; Mohapatra, Birendra K.

    2016-06-01

    Bog manganese ore, associated with the banded iron formation of the Iron Ore Group (IOG), occurs in large volume in northern Odisha, India. The ore is powdery, fine-grained and soft in nature with varying specific gravity (2.8-3.9 g/cm3) and high thermo-gravimetric loss, It consists of manganese (δ-MnO2, manganite, cryptomelane/romanechite with minor pyrolusite) and iron (goethite/limonite and hematite) minerals with sub-ordinate kaolinite and quartz. It shows oolitic/pisolitic to globular morphology nucleating small detritus of quartz, pyrolusite/romanechite and hematite. The ore contains around 23% Mn and 28% Fe with around 7% of combined alumina and silica. Such Mn ore has not found any use because of its sub-grade nature and high iron content, and is hence considered as waste. The ore does not respond to any physical beneficiation techniques because of the combined state of the manganese and iron phases. Attempts have been made to recover manganese and iron value from such ore through smelting. A sample along with an appropriate charge mix when processed through a plasma reactor, produced high-manganese steel alloy having 25% Mn within a very short time (<10 min). Minor Mn content from the slag was recovered through acid leaching. The aim of this study has been to recover a value-added product from the waste.

  4. 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.

  5. Detection of copper, lead, cadmium and iron in wine using electronic tongue sensor system.

    PubMed

    Simões da Costa, A M; Delgadillo, I; Rudnitskaya, A

    2014-11-01

    An array of 10 potentiometric chemical sensors has been applied to the detection of total Fe, Cu, Pb and Cd content in digested wine. As digestion of organic matter of wine is necessary prior to the trace metal detection using potentiometric sensors, sample preparation procedures have been optimized. Different variants of wet and microwave digestion and dry ashing, 14 conditions in total, have been tested. Decomposition of organic matter was assessed using Fourier transform mid-infrared spectroscopy and total phenolic content. Dry ashing was found to be the most effective method of wine digestion. Measurements with sensors in individual solutions of Fe(III), Cu(II), Pb(II) and Cd(II) prepared on different backgrounds have shown that their detection limits were below typical concentration levels of these metals in wines and, in the case of Cu, Pb and Cd below maximum allowed concentrations. Detection of Fe in digested wine samples was possible using discrete iron-sensitive sensors with chalcogenide glass membranes with RMSEP of 0.05 mmol L(-1) in the concentration range from 0.0786 to 0.472 mmol L(-1). Low concentration levels of Cu, Pb and Cd in wine and cross-sensitivity of respective sensors resulted in the non-linearity of their responses, requiring back-propagation neural network for the calibration. Calibration models have been calculated using measurements in the model mixed solutions containing all three metals and a set of digested wine sample. RMSEP values for Cu, Pb and Cd were 3.9, 39 and 1.2 μmol L(-1) in model solutions and 2, 150 and 1 μmol L(-1) in digested wine samples.

  6. Determination of mercury, cadmium, lead, zinc, selenium and iron by ICP-OES in mushroom samples from around thermal power plant in Muğla, Turkey.

    PubMed

    Kula, Ibrahim; Solak, M Halil; Uğurlu, Mehmet; Işıloğlu, Mustafa; Arslan, Yasin

    2011-09-01

    Scleroderma verrucosum, Stropharia coronilla, Lactarius deterrimus, Chroogomphus rutilus, Russula delica, Laccaria laccata, Clitocybe odora var. alba, Lyophyllum decastes, Coprinus comatus, Helvella leucomelaena, Melanoleuca cognata, Melanoleuca cognata, Paxina acetabulum, Clitocybe vermicularis, Sarcosphaera crassa, Rhizopogon roseolu and Thelephora caryophyllea were collected from different localities in Muğla-Yatağan region of Turkey. Their trace metals concentrations were determined by ICPOES after microwave digestion. The results were 0.37 ± 0.01-5.28 ± 0.21 for cadmium, 467 ± 19-3,280 ± 131 for iron, 0.69 ± 0.03-9.15 ± 0.37 for lead, 18.70 ± 0.75-67.10 ± 2.68 for selenium, 75 ± 3-213 ± 8 for zinc and 0.15 ± 0.01-0.55 ± 0.01 for mercury (as μg/g). The detection limits for ICPOES were found as 0.25 for Cadmium, 0.2 for iron, 0.1 for lead, 0.5 for selenium, 0.2 for zinc and 0.03 for mercury (as mg L(-1)). The Relatively Standard Deviations (R.S.D.) were found below 4.0%. The accuracy of procedure was confirmed by certified reference material.

  7. 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

    Passlack, Nadine; 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.

  8. Material and detector properties of cadmium manganese telluride (Cd1-xMnxTe) crystals grown by the modified floating-zone method

    SciTech Connect

    Hossain, A.; Gu, G. D.; Bolotnikov, A. E.; Camarda, G. S.; Cui, Y.; Roy, U. N.; Yang, G.; Liu, T.; Zhong, R.; Schneelock, J.; James, R. B.

    2014-12-24

    We demonstrated the material- and radiation-detection properties of cadmium manganese telluride (Cd1-xMnxTe; x=0.06), a wide-band-gap semiconductor crystal grown by the modified floating-zone method. We investigated the presence of various bulk defects, such as Te inclusions, twins, and dislocations of several as-grown indium-doped Cd1-xMnxTe crystals using different techniques, viz., IR transmission microscopy, and chemical etching. We then fabricated four planar detectors from selected CdMnTe crystals, characterized their electrical properties, and tested their performance as room-temperature X- and gamma-ray detectors. Thus, our experimental results show that CMT crystals grown by the modified floating zone method apparently are free from Te inclusions. However, we still need to optimize our growth parameters to attain high-resistivity, large-volume single-crystal CdMnTe.

  9. Study on determination of iron, cobalt, nickel, copper, zinc and manganese in drinking water by solid-phase extraction and RP-HPLC with 2-(2-quinolinylazo)-5-diethylaminophenol as precolumn derivatizing reagent.

    PubMed

    Hu, Qiufen; Yang, Guanyu; Yang, Jihong; Yin, Jiayuan

    2002-12-01

    A new method for the determination of iron, cobalt, nickel, copper, zinc and manganese in drinking water by the reversed-phase high-performance liquid chromatography (RP-HPLC) with 2-(2-quinolinylazo)-5-diethylaminophenol (QADEAP) as precolumn derivatizing reagent was studied in this paper. The iron, cobalt, nickel, copper, zinc, and manganese ions react with QADEAP to form color chelates in the presence of cetyl trimethylammonium bromide (CTMAB) and acetic acid-sodium acetic buffer solution medium of pH 4.0. These chelates were enriched by solid-phase extraction with a Waters Nova-Pak C18 cartridge and eluted the retained chelates from the cartridge with tetrahydrofuran (THF). The enrichment factor of 100 was achieved. Then the chelates were separated on a Waters Nova-Pak C18 column (3.9 x 150 mm, 5 microm) by gradient elution with methanol (containing 0.2% of acetic acid and 0.1% of CTMAB) and 0.05 mol L(-1) acetic acid-sodium acetic buffer solution (containing 0.1% of CTMAB) (pH 4.0) as mobile phase at a flow rate of 0.5 ml min(-1), and monitored with a photodiode array detector from 450 approximately 700 nm. The detection limits (S/N = 3) of iron, cobalt, nickel, copper, zinc and manganese are 0.8, 1.1, 0.9, 1.1, 1.5 and 2.0 ng L(-1), respectively, in the original sample. This method can be applied to determination at the microg L(-1) level of iron, cobalt, nickel, copper, zinc and manganese in drinking water with good results.

  10. Manganese and iron reduction dominate organic carbon oxidation in surface sediments of the deep Ulleung Basin, East Sea

    NASA Astrophysics Data System (ADS)

    Hyun, Jung-Ho; Kim, Sung-Han; Mok, Jin-Sook; Cho, Hyeyoun; Lee, Tongsup; Vandieken, Verona; Thamdrup, Bo

    2017-03-01

    Rates and pathways of benthic organic carbon (Corg) oxidation were investigated in surface sediments of the Ulleung Basin (UB) characterized by high Corg contents ( > 2.5 %, dry wt.) and very high contents of Mn oxides ( > 200 µmol cm-3) and Fe oxides (up to 100 µmol cm-3). The combination of geochemical analyses and independently executed metabolic rate measurements revealed that Mn and Fe reduction were the dominant Corg oxidation pathways in the center of the UB, comprising 45 and 20 % of total Corg oxidation, respectively. By contrast, sulfate reduction was the dominant Corg oxidation pathway, accounting for 50 % of total Corg mineralization in sediments of the continental slope. The relative significance of each Corg oxidation pathway matched the depth distribution of the respective electron acceptors. The relative importance of Mn reduction for Corg oxidation displays saturation kinetics with respect to Mn oxide content with a low half-saturation value of 8.6 µmol cm-3, which further implies that Mn reduction can be a dominant Corg oxidation process even in sediments with lower MnO2 content as known from several other locations. This is the first report of a high contribution of manganese reduction to Corg oxidation in offshore sediments on the Asian margin. The high manganese oxide content in the surface sediment in the central UB was maintained by an extreme degree of recycling, with each Mn atom on average being reoxidized ˜ 3800 times before permanent burial. This is the highest degree of recycling so far reported for Mn-rich sediments, and it appears linked to the high benthic mineralization rates resulting from the high Corg content that indicate the UB as a biogeochemical hotspot for turnover of organic matter and nutrient regeneration.

  11. X-Ray Microanalytic Concentration Measurements in Unsectioned Specimens: a Technique and its Application to Zinc, Manganese, and Iron Enriched Mechanical Structures of Organisms from Three Phyla

    NASA Astrophysics Data System (ADS)

    Schofield, Robert M. S.

    A method for measuring concentrations of minor elements in microscopic volumes of heterogeneous, unsectioned biological specimens using an ion microprobe is developed. The element quantity is obtained from PIXE (Proton Induced X-ray Emission) and the total quantity of material is derived from STIM (Scanning Transmission Ion Microscopy) energy loss measurements. Sources of error, including changes in x-ray production cross section with proton energy and absorption of induced x-rays, are discussed and a method of calculating the total measurement uncertainty, typically about 25% here, is developed. The measurement accuracy is shown to be improved for symmetric specimens, and a method of using the bremsstrahlung background to correct for x-ray attenuation within irregular specimens is developed. Methods for measuring local concentrations in internal features are also discussed. With this technique, scorpions were found to contain cuticular accumulations of one or more heavy metals (manganese up to 5% of dry weight, iron up to 8%, zinc up to 24%) in the chelicera, pedipalp denticles, tarsal claws, and stingers; different region soften contained different metals. The stingers are argued to be of particular interest because they are not homologous to legs. Similar accumulations were found in spiders, some other chelicerates and crustaceans. Previous reports of manganese and zinc accumulations in insect and worm mouth parts were augmented with local concentration measurements and with the detection of other enrichment features (such as 6% iron in the paragnaths of the worm Nereis vexillosa). Zinc accumulations (up to only 0.1%) were also found in the tips of the teeth of a hagfish, Myxine + glutinosa. X-ray images of several of these features are presented. It is argued that the extreme magnitude of some concentration values suggests that some metals are incorporated in unusual biominerals rather than organically bound. Results of x-ray diffractometry and Vickers

  12. Mineral of the month: manganese

    USGS Publications Warehouse

    Corathers, Lisa A.

    2005-01-01

    Manganese is one of the most important ferrous metals and one of the few for which the United States is totally dependent on imports. It is a black, brittle element predominantly used in metallurgical applications as an alloying addition, particularly in steel and cast iron production, which together provide the largest market for manganese (about 83 percent). It is also used as an alloy with nonferrous metals such as aluminum and copper. Nonmetallurgical applications of manganese include battery cathodes, soft ferrite magnets used in electronics, micronutrients found in fertilizers and animal feed, water treatment chemicals, and a colorant for bricks and ceramics.

  13. 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

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

    2009-07-24

    Manganese (Mn) is an essential trace element, but overexposure is characterized by Parkinson's like symptoms in extreme cases. Previous studies have shown that 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). (3)H-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 (3)H-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 alpha(2) adrenergic receptor. For example, elevated brain Mn and decreased Fe caused an approximate 50% decrease in NET and alpha(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.

  14. Manganese oxide supported on gold/iron as a water-oxidizing catalyst in artificial photosynthetic systems.

    PubMed

    Najafpour, Mohammad Mahdi; Hosseini, Seyedeh Maedeh; Zand, Zahra

    2016-05-31

    Herein, we reported that KMnO4 with iron nanoparticles coated with gold layers was a promising catalyst for water oxidation. The compound was characterized by scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, atomic absorption spectroscopy and electrochemistry. The new compound was a conductive, recyclable, highly dispersible, magnetically separable, environmentally friendly, and nano-sized catalyst for water oxidation via cerium(iv) ammonium nitrate or Ru(bpy)3(3+) and electrochemical water oxidation. The turnover frequency of Mn oxide/gold/iron for water oxidation via cerium(iv) ammonium nitrate is 0.4 mmol O2 per mol Mn per second, which shows that this catalyst is among the best Mn-based catalysts for water oxidation. We also showed a strategy for placing this catalyst on the surface of an electrode without adding any other compounds.

  15. Effect of iron-manganese-sepiolite as heterogeneous Fenton-like catalyst on the performance and microbial community of anaerobic granular sludge treatment system.

    PubMed

    Su, Chengyuan; Li, Weiguang; Chen, Menglin; Huang, Zhi; Wu, Lei

    2016-01-01

    Both short-term and long-term exposure experiments have been carried out to investigate the influence of iron (Fe)-manganese (Mn)-sepiolite, as a heterogeneous Fenton-like catalyst, on the performance and microbial community of anaerobic granular sludge. During the short-term exposure experiments, chemical oxygen demand (COD) removal efficiency decreased from 73.1% to 64.1% with the presence of 100mg/L of catalyst. However, long-term exposure to the catalyst did not significantly affect the COD removal efficiency (81.8%) as compared to the control (83.5%). Meanwhile, the absorption peaks of coenzyme F420 in extracellular polymeric substances (EPS) of sludge samples were remarkable by excitation-emission matrix (EEM) fluorescence spectra. After long-term exposure, the presence of the catalyst increased secretions of EPS from 83.7mg/g VSS to 89.1mg/g VSS. Further investigations with high throughput sequencing indicated that the abundance of Methanosaeta increased from 57.7% to 70.4% after long-term exposure. In bacterial communities, Proteobacteria, Firmicutes, and Synergistetes were predominant.

  16. Manganese-incorporated iron(III) oxide-graphene magnetic nanocomposite: synthesis, characterization, and application for the arsenic(III)-sorption from aqueous solution

    NASA Astrophysics Data System (ADS)

    Nandi, Debabrata; Gupta, Kaushik; Ghosh, Arup Kumar; De, Amitabha; Banerjee, Sangam; Ghosh, Uday Chand

    2012-12-01

    High specific surface area of graphene (GR) has gained special scientific attention in developing magnetic GR nanocomposite aiming to apply for the remediation of diverse environmental problems like point-of-use water purification and simultaneous separation of contaminants applying low external magnetic field (<1.0 T) from ground water. Fabrication of magnetic manganese-incorporated iron(III) oxide (Mn x 2+Fe2- x 3+O4 2-) (IMBO)-GR nanocomposite is reported by exfoliating the GR layers. Latest microscopic, spectroscopic, powder X-ray diffraction, BET surface area, and superconducting quantum interference device characterizations showed that the material is a magnetic nanocomposite with high specific surface area (280 m2 g-1) and pore volume (0.3362 cm3 g-1). Use of this composite for the immobilization of carcinogenic As(III) from water at 300 K and pH 7.0 showed that the nanocomposite has higher binding efficiency with As(III) than the IMBO owing to its high specific surface area. The composite showed almost complete (>99.9 %) As(III) removal (≤10 μg L-1) from water. External magnetic field of 0.3 T efficiently separated the water dispersed composite (0.01 g/10 mL) at room temperature (300 K). Thus, this composite is a promising material which can be used effectively as a potent As(III) immobilizer from the contaminated groundwater (>10 μg L-1) to improve drinking water quality.

  17. Ferromagnets based on diamond-like semiconductors GaSb, InSb, Ge, and Si supersaturated with manganese or iron impurities during laser-plasma deposition

    SciTech Connect

    Demidov, E. S.; Podol'skii, V. V.; Lesnikov, V. P.; Sapozhnikov, M. V.; Druzhnov, D. M.; Gusev, S. N.; Gribkov, B. A.; Filatov, D. O.; Stepanova, Yu. S.; Levchuk, S. A.

    2008-01-15

    Properties of thin (30-100 nm) layers of diluted magnetic semiconductors based on diamond-like compounds III-V (InSb and GaSb) and elemental semiconductors Ge and Si doped with 3d impurities of manganese and iron up to 15% were measured and discussed. The layers were grown by laser-plasma deposition onto heated single-crystal gallium arsenide or sapphire substrates. The ferromagnetism of layers with the Curie temperature up to 500 K appeared in observations of the ferromagnetic resonance, anomalous Hall effect, and magneto-optic Kerr effect. The carrier mobility of diluted magnetic semiconductors is a hundred times larger than that of the previously known highest temperature magnetic semiconductors, i.e., copper and chromium chalcogenides. The difference between changes in the magnetization with temperature in diluted semiconductors based on III-V, Ge, and Si was discussed. A complex structure of the ferromagnetic resonance spectrum in Si:Mn/GaAs was observed. The results of magnetic-force microscopy showed a weak correlation between the surface relief and magnetic inhomogeneity, which suggests that the ferromagnetism is caused by the 3d-impurity solid solution, rather than ferromagnetic phase inclusions.

  18. Method development for the determination of calcium, copper, magnesium, manganese, iron, potassium, phosphorus and zinc in different types of breads by microwave induced plasma-atomic emission spectrometry.

    PubMed

    Ozbek, Nil; Akman, Suleyman

    2016-06-01

    A novel method was developed for the determination of calcium, magnesium, potassium, iron, copper, zinc, and manganese and phosphorous in various kinds of breads samples sold in Turkey by microwave plasma-atomic emission spectrometry (MIP-AES). Breads were dried at 100 °C for one day, ground thoroughly and then digested using nitric acid/hydrogen per oxide (3:1). The analytes in certified reference wheat flour and maize flour samples were determined in the uncertainty limits of the certified values as well as the analytes added to the mixture of ground bread and acid mixture prior to digestion were recovered quantitatively (>90%). Therefore, all determinations were made by linear calibration technique using aqueous standards. The LOD values for Ca, Cu, Fe, K, Mg, Mn, P and Zn were 13.1, 0.28, 4.47, 118, 1.10, 0.41, 7550 and 3.00 ng mL(-1), respectively. No spectral interference was detected at the working wavelengths of the analytes.

  19. Reactions of hydrogen peroxide with superoxide dismutase from Propionibacterium shermanii--an enzyme which is equally active with iron or manganese--are independent of the prosthetic metal.

    PubMed

    Meier, B; Sehn, A P; Michel, C; Saran, M

    1994-09-01

    Propionibacterium shermanii contains a single constitutive superoxide dismutase (SOD) which is active with either iron or manganese incorporated in the same protein moiety. Copper and cobalt can also be incorporated by the bacteria in the active center of the SOD under conditions of metal deficiency, but in this case the enzyme is enzymatically inactive. In contrast to other bacterial SODs, the Fe-SOD of P. shermanii remains highly resistant to inactivation by hydrogen peroxide, as does Mn-SOD. Both SOD types cannot be distinguished by their inactivation patterns. Incubation with hydrogen peroxide results in a concentration- and time-dependent decrease in tryptophan fluorescence, independent of the metal present in the active center. Moreover, the Fe-SOD shows a time-dependent decrease in spin concentration after addition of hydrogen peroxide, which reflects alterations in the environment of the metal rather than a reduction of Fe3+ to Fe2+. No obvious correlations exist, however, between these effects and the enzymatic activity of the enzyme. The resistance of the SODs from P. shermanii to inactivation by hydrogen peroxide seems to be caused by the fact that a tryptophan residue near the metal-chelating histidine-75--which is present in all Fe-SODs being rapidly inactivated by this agent--is exchanged for valine.

  20. Hydroxyapatite formation on titania-based materials in a solution mimicking body fluid: Effects of manganese and iron addition in anatase.

    PubMed

    Shin, Euisup; Kim, Ill Yong; Cho, Sung Baek; Ohtsuki, Chikara

    2015-03-01

    Hydroxyapatite formation on the surfaces of implanted materials plays an important role in osteoconduction of bone substitutes in bone tissues. Titania hydrogels are known to instigate hydroxyapatite formation in a solution mimicking human blood plasma. To date, the relationship between the surface characteristics of titania and hydroxyapatite formation on its surface remains unclear. In this study, titania powders with varying surface characteristics were prepared by addition of manganese or iron to examine hydroxyapatite formation in a type of simulated body fluid (Kokubo solution). Hydroxyapatite formation was monitored by observation of deposited particles with scale-like morphology on the prepared titania powders. The effect of the titania surface characteristics, i.e., crystal structure, zeta potential, hydroxy group content, and specific surface area, on hydroxyapatite formation was examined. Hydroxyapatite formation was observed on the surface of titania powders that were primarily anatase, and featured a negative zeta potential and low specific surface areas irrespective of the hydroxy group content. High specific surface areas inhibited the formation of hydroxyapatite because calcium and phosphate ions were mostly consumed by adsorption on the titania surface. Thus, these surface characteristics of titania determine its osteoconductivity following exposure to body fluid.

  1. Chemical versus Enzymatic Digestion of Contaminated Estuarine Sediment: Relative Importance of Iron and Manganese Oxides in Controlling Trace Metal Bioavailability

    NASA Astrophysics Data System (ADS)

    Turner, A.; Olsen, Y. S.

    2000-12-01

    Chemical and enzymatic reagents have been employed to determine available concentrations of Fe, Mn, Cu and Zn in contaminated estuarine sediment. Gastric and intestinal enzymes (pepsin, pH 2, and trypsin, pH 7·6, respectively) removed significantly more metal than was water-soluble or exchangeable (by seawater or ammonium acetate), while gastro-intestinal fluid of the demersal teleost, Pleuronectes platessa L. (plaice), employed to operationally define a bioavailable fraction of contaminants, generally solubilized more metal than the model enzymes. Manganese was considerably more available than Fe under these conditions and it is suggested that the principal mechanism of contaminant release is via surface complexation and reductive solubilization of Mn oxides, a process which is enhanced under conditions of low pH. Of the chemical reagents tested, acetic acid best represents the fraction of Mn (as well as Cu and Zn) which is available under gastro-intestinal conditions, suggesting that the reducing tendency of acetate is similar to that of the ligands encountered in the natural digestive environment. Although the precise enzymatic and non-enzymatic composition of plaice gastro-intestinal fluid may be different to that encountered in more representative, filter-feeding or burrowing organisms, a general implication of this study is that contaminants associated with Mn oxides are significantly more bioavailable than those associated with Fe oxides, and that contaminant bioavailability may be largely dictated by the oxidic composition of contaminated sediment.

  2. Manganese nodules: thorium-230: protactinium-231 ratios.

    PubMed

    Sackett, W M

    1966-11-04

    The Th(230): Pa(231) activity ratio in 7 of 11 manganese nodules is less than 10.8, the theoretical production ratio of activities in the ocean. This finding indicates difierential accumulation of these nuclides in authigenic deposits of manganese-iron oxide.

  3. Manganese oxide-induced strategy to high-performance iron/nitrogen/carbon electrocatalysts with highly exposed active sites

    NASA Astrophysics Data System (ADS)

    Sun, Tao; Wu, Qiang; Zhuo, Ou; Jiang, Yufei; Bu, Yongfeng; Yang, Lijun; Wang, Xizhang; Hu, Zheng

    2016-04-01

    Iron/nitrogen/carbon (Fe/N/C) catalyst is so far the most promising non-precious metal electrocatalyst for oxygen reduction reaction (ORR) in acidic medium, whose performance depends closely on the synthesis chemistry. Herein, we report a MnOx-induced strategy to construct the Fe/N/C with highly exposed Fe-Nx active sites, which involves the uniform spreading of polyaniline on hierarchical N-doped carbon nanocages by a reactive-template polymerization, followed by the successive iron incorporation and polyaniline pyrolysis. The resulting Fe/N/C demonstrates an excellent ORR performance, including an onset potential of 0.92 V (vs. RHE), four electron selectivity, superb stability and immunity to methanol crossover. The excellent performance is well correlated with the greatly enhanced surface active sites of the catalyst stemming from the unique MnOx-induced strategy. This study provides an efficient approach for exploring the advanced ORR electrocatalysts by increasing the exposed active sites.Iron/nitrogen/carbon (Fe/N/C) catalyst is so far the most promising non-precious metal electrocatalyst for oxygen reduction reaction (ORR) in acidic medium, whose performance depends closely on the synthesis chemistry. Herein, we report a MnOx-induced strategy to construct the Fe/N/C with highly exposed Fe-Nx active sites, which involves the uniform spreading of polyaniline on hierarchical N-doped carbon nanocages by a reactive-template polymerization, followed by the successive iron incorporation and polyaniline pyrolysis. The resulting Fe/N/C demonstrates an excellent ORR performance, including an onset potential of 0.92 V (vs. RHE), four electron selectivity, superb stability and immunity to methanol crossover. The excellent performance is well correlated with the greatly enhanced surface active sites of the catalyst stemming from the unique MnOx-induced strategy. This study provides an efficient approach for exploring the advanced ORR electrocatalysts by increasing the

  4. 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.

  5. 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 ...

  6. The resistance to embrittlement by a hydrogen environment of selected high strength iron-manganese base alloys

    NASA Technical Reports Server (NTRS)

    Benson, R. B., Jr.; Kim, D. K.; Atteridge, D.; Gerberich, W. W.

    1974-01-01

    Fe-16Mn and Fe-25Mn base alloys, which had been cold worked to yield strength levels of 201 and 178 KSI, were resistant to degradation of mechanical properties in a one atmosphere hydrogen environment at ambient temperature under the loading conditions employed in this investigation. Transmission electron microscopy established that bands of epsilon phase martensite and fcc mechanical twins were formed throughout the fcc matrix when these alloys were cold worked. In the cold worked alloys a high density of crystal defects were observed associated with both types of strain induced structures, which should contribute significantly to the strengthening of these alloys. High strength iron base alloys can be produced which appear to have some resistance to degradation of mechanical properties in a hydrogen environment under certain conditions.

  7. In vitro and in vivo corrosion properties of new iron-manganese alloys designed for cardiovascular applications.

    PubMed

    Drynda, Andreas; Hassel, Thomas; Bach, Friedrich Wilhelm; Peuster, Matthias

    2015-04-01

    The principle of biodegradation for the production of temporary implant materials (e.g. stents) plays an important role in the treatment of congenital heart defects. In the last decade several attempts have been made with different alloy materials-mainly based on iron and magnesium. None of the currently available materials in this field have demonstrated satisfying results and have therefore not found entry into broad clinical practice. While magnesium or magnesium alloy systems corrode too fast, the corrosion rate of pure iron-stents is too slow for cardiovascular applications. In the last years FeMn alloy systems were developed with the idea that galvanic effects, caused by different electrochemical properties of Fe and Mn, would increase the corrosion rate. In vitro tests with alloys containing up to 30% Mn showed promising results in terms of biocompatibility. This study deals with the development of new FeMn alloy systems with lower Mn concentrations (FeMn 0.5 wt %, FeMn 2.7 wt %, FeMn 6.9 wt %) to avoid Mn toxicity. Our results show, that these alloys exhibit good mechanical features as well as suitable in vitro biocompatibility and corrosion properties. In contrast, the evaluation of these alloys in a mouse model led to unexpected results-even after 9 months no significant corrosion was detectable. Preliminary SEM investigations showed that passivation layers (FeMn phosphates) might be the reason for corrosion resistance. If this can be proved in further experiments, strategies to prevent or dissolve those layers need to be developed to expedite the in vivo corrosion of FeMn alloys.

  8. Magnetic iron oxide and manganese-doped iron oxide nanoparticles for the collection of alpha-emitting radionuclides from aqueous solutions

    SciTech Connect

    O'Hara, Matthew J.; Carter, Jennifer C.; Warner, Cynthia L.; Warner, Marvin G.; Addleman, R. Shane

    2016-10-31

    Magnetic nanoparticles are well known to possess chemically active surfaces and high surface areas that can be employed to extract a range of ions from aqueous solutions. Additionally, their paramagnetic property provides a convenient means for bulk collection of the material from solution after the targeted ions have been adsorbed. Herein, two nanoscale amphoteric metal oxides, each possessing useful magnetic attributes, were evaluated for their ability to collect both naturally occurring radioactive isotopes (polonium (Po), radium (Ra), and uranium (U)) as well as the transuranic element americium (Am) from a suite of naturally occurring aqueous matrices. The nanomaterials include commercially available paramagnetic magnetite (Fe3O4) and magnetite that was modified to incorporate manganese (Mn) into the crystal structure. The chemical stability of these nanomaterials was evaluated in Hanford Site, WA ground water between the natural pH (~8) and pH 1 (acidified with HCl). Whereas the magnetite was observed to have good stability over the pH range, the Mn-doped material was observed to leach Mn at low pH. The materials were evaluated in parallel to characterize their uptake performance of the aforementioned alpha-emitting radionuclide spikes from Hanford Site ground water across a range of pH (from ~8 down to 2). In addition, radiotracer uptake experiments were performed on Columbia River water, seawater, and human urine at their natural pH and at pH 2. Despite the observed leaching of Mn from the Mn-doped nanomaterial in the lower pH range, it exhibited generally superior analyte extraction performance compared to the magnetite, and analyte uptake was observed across a broader pH range. The uptake behavior of the various radiotracers on these two materials at different pH levels can generally be explained by the amphoteric nature of the nanoparticle surfaces. Finally, the rate of sorption of the radiotracers on the two materials in unacidified groundwater was

  9. Magnetic iron oxide and manganese-doped iron oxide nanoparticles for the collection of alpha-emitting radionuclides from aqueous solutions

    DOE PAGES

    O'Hara, Matthew J.; Carter, Jennifer C.; Warner, Cynthia L.; ...

    2016-10-31

    Magnetic nanoparticles are well known to possess chemically active surfaces and large surface areas that can be employed to extract a range of ions from aqueous solutions. In addition, their superparamagnetic properties provide a convenient means for bulk collection of the material from solution after the targeted ions have been adsorbed. We evaluated two nanoscale amphoteric metal oxides, each possessing useful magnetic attributes for their ability to collect trace levels of a chemically diverse range of alpha emitting radioactive isotopes (polonium (Po), radium (Ra), uranium (U), and americium (Am)) from a wide range of aqueous solutions. The nanomaterials include commerciallymore » available magnetite (Fe3O4) and magnetite modified to incorporate manganese (Mn) into the crystal structure. The chemical stability of these nanomaterials was evaluated in Hanford Site, WA ground water between the natural pH (~8) and pH 1. Whereas the magnetite was observed to have good stability over the pH range, the Mn-doped material was observed to leach Mn at low pH. The materials were evaluated in parallel to characterize their uptake performance of the alpha-emitting radionuclide spikes from ground water across a range of pH (from ~8 down to 2). In addition, radiotracer uptake experiments were performed on Columbia River water, seawater, and human urine at their natural pH and at pH 2. Despite the observed leaching of Mn from the Mn-doped nanomaterial in the lower pH range, it exhibited generally superior analyte extraction performance compared to the magnetite, and analyte uptake was observed across a broader pH range. We show that the uptake behavior of the various radiotracers on these two materials at different pH levels can generally be explained by the amphoteric nature of the nanoparticle surfaces. Finally, the rate of sorption of the radiotracers on the two materials in unacidified ground water was evaluated. The uptake curves generally indicate that equilibrium is

  10. Magnetic iron oxide and manganese-doped iron oxide nanoparticles for the collection of alpha-emitting radionuclides from aqueous solutions

    SciTech Connect

    O'Hara, Matthew J.; Carter, Jennifer C.; Warner, Cynthia L.; Warner, Marvin G.; Addleman, R. Shane

    2016-10-31

    Magnetic nanoparticles are well known to possess chemically active surfaces and large surface areas that can be employed to extract a range of ions from aqueous solutions. In addition, their superparamagnetic properties provide a convenient means for bulk collection of the material from solution after the targeted ions have been adsorbed. We evaluated two nanoscale amphoteric metal oxides, each possessing useful magnetic attributes for their ability to collect trace levels of a chemically diverse range of alpha emitting radioactive isotopes (polonium (Po), radium (Ra), uranium (U), and americium (Am)) from a wide range of aqueous solutions. The nanomaterials include commercially available magnetite (Fe3O4) and magnetite modified to incorporate manganese (Mn) into the crystal structure. The chemical stability of these nanomaterials was evaluated in Hanford Site, WA ground water between the natural pH (~8) and pH 1. Whereas the magnetite was observed to have good stability over the pH range, the Mn-doped material was observed to leach Mn at low pH. The materials were evaluated in parallel to characterize their uptake performance of the alpha-emitting radionuclide spikes from ground water across a range of pH (from ~8 down to 2). In addition, radiotracer uptake experiments were performed on Columbia River water, seawater, and human urine at their natural pH and at pH 2. Despite the observed leaching of Mn from the Mn-doped nanomaterial in the lower pH range, it exhibited generally superior analyte extraction performance compared to the magnetite, and analyte uptake was observed across a broader pH range. We show that the uptake behavior of the various radiotracers on these two materials at different pH levels can generally be explained by the amphoteric nature of the nanoparticle surfaces. Finally, the rate of sorption of the radiotracers on the two materials in unacidified ground water was evaluated. The uptake curves generally indicate that equilibrium is obtained

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

    SciTech Connect

    Han, Jeongoh; Lee, Jong-Suk; Choi, Daekyu; Lee, Youna; Hong, Sungchae; Choi, Jungyun; Han, Songyi; Ko, Yujin; Kim, Jung-Ae; Mi Kim, Young; Jung, Yunjin

    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.

  12. Evaluation of the Accumulation of Trace Metals (as, U, CR, CU, PB, Zn) on Iron-Manganese Coatings on in Situ Stream Pebbles and Emplaced Substrates

    NASA Astrophysics Data System (ADS)

    Turpin, M. M.; Blake, J.; Crossey, L. J.; Ali, A.; Hansson, L.

    2015-12-01

    Exposure to trace metals (As, U, Cr, Cu, Pb, Zn) has potential negative health effects on human populations and wildlife. Geothermal waters often have elevated concentrations of trace elements and understanding the geochemical cycling of these elements can be challenging. Previous studies have utilized in situ stream pebbles and glass or ceramic substrates with iron-manganese oxide coatings to understand contamination and or chemical cycling. This project's main focus is to develop an ideal tracing method using adsorption onto substrate surfaces and to define key parameters that are necessary for the phenomenon of adsorption between trace metals and these surface coatings to occur. Sampling locations include the Jemez River and Rio San Antonio in the Jemez mountains, northern New Mexico. Both streams have significant geothermal inputs. Pebbles and cobbles were gathered from the active stream channel and 6mm glass beads and 2 X1 in. ceramic plates were placed in streams for three weeks to allow for coating accumulation. Factors such as leachate type, water pH, substrate type, coating accumulation period and leach time were all considered in this experiment. It was found that of the three leachates (aqua regia, 10% aqua regia and hydroxylamine), hydroxylamine was the most effective at leaching coatings without dissolving substrates. Samples leached with aqua regia and 10% aqua regia were found to lose weight and mass over the following 5, 7, and 10 day measurements. Glass beads were determined to be more effective than in stream pebbles as an accumulation substrate: coatings were more easily controlled and monitored. Samples leached with hydroxylamine for 5 hours and 72 hours showed little difference in their leachate concentrations, suggesting that leach time has little impact on the concentration of leachate samples. This research aims to find the best method for trace metal accumulation in streams to aid in understanding geochemical cycling.

  13. 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).

  14. A Comparative Analysis of the Contents Of Iron, Zinc, Copper, Manganese, and Calcium in the Collective Diet Of Preschool Children in the Northwestern Region of Bosnia.

    PubMed

    Đermanović, Mirjana; Miletić, Ivanka; Pavlović, Zoran

    2017-01-01

    Researches conducted worldwide indicate a frequent deficiency in mineral matters. Due to the increased need during the period of accelerated growth and development, children belong to the group that is exposed to the highest risk of mineral matter deficiency. Our objectives were to determine the iron, zinc, copper, manganese, and calcium intake in the collective diet of the preschool population in the in the northwestern region of Bosnia- in the Republic of Srpska and to estimate the adequacy of the application of the international food composition tables for nutrition planning relating to mineral matters. Samples of food intended for children's diet were collected in the preschool institution "Radost" (a kindergarten), in the city of Prijedor. In daily portions, Fe, Zn, Cu, Mn, and Ca contents were determined by flame atomic absorption spectrophotometry. Contents of mineral matters in daily meals were also calculated by the food composition tables. An average daily meal contained 2.86 mg of Fe, 1.71 mg of Zn, 0.19 mg of Cu, 0.21 mg of Mn, and 83.5 mg of Ca. With calculation method, contents of all minerals are significantly higher than the experimental data for all used food composition tables. The obtained results indicate a significant deficiency in mineral matters in the collective diet of the preschool population in the Republic of Srpska, a certain non-compliance with the applicable recommendations, and also suggest a need to create food composition tables for food being consumed in our region.

  15. 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.

  16. Steel dust in the New York City subway system as a source of manganese, chromium, and iron exposures for transit workers.

    PubMed

    Chillrud, Steven N; Grass, David; Ross, James M; Coulibaly, Drissa; Slavkovich, Vesna; Epstein, David; Sax, Sonja N; Pederson, Dee; Johnson, David; Spengler, John D; Kinney, Patrick L; Simpson, H James; Brandt-Rauf, Paul

    2005-03-01

    The United States Clean Air Act Amendments of 1990 reflected increasing concern about potential effects of low-level airborne metal exposure on a wide array of illnesses. Here we summarize results demonstrating that the New York City (NYC) subway system provides an important microenvironment for metal exposures for NYC commuters and subway workers and also describe an ongoing pilot study of NYC transit workers' exposure to steel dust. Results from the TEACH (Toxic Exposure Assessment, a Columbia and Harvard) study in 1999 of 41 high-school students strongly suggest that elevated levels of iron, manganese, and chromium in personal air samples were due to exposure to steel dust in the NYC subway. Airborne concentrations of these three metals associated with fine particulate matter were observed to be more than 100 times greater in the subway environment than in home indoor or outdoor settings in NYC. While there are currently no known health effects at the airborne levels observed in the subway system, the primary aim of the ongoing pilot study is to ascertain whether the levels of these metals in the subway air affect concentrations of these metals or related metabolites in the blood or urine of exposed transit workers, who due to their job activities could plausibly have appreciably higher exposures than typical commuters. The study design involves recruitment of 40 transit workers representing a large range in expected exposures to steel dust, the collection of personal air samples of fine particulate matter, and the collection of blood and urine samples from each monitored transit worker.

  17. Synthesis and characterization of three-coordinate and related beta-diketiminate derivatives of manganese, iron, and cobalt.

    PubMed

    Panda, Arunashree; Stender, Matthias; Wright, Robert J; Olmstead, Marilyn M; Klavins, Peter; Power, Philip P

    2002-07-29

    Treatment of M[N(SiMe(3))(2)](2) (M = Mn, Fe, Co) with various bulky beta-diketimines afforded a variety of new three-coordinate complexes which were characterized by UV-vis, (1)H NMR and IR spectroscopy, magnetic measurements, and X-ray crystallography. Reaction of the beta-diketimine H(Dipp)NC(Me)CHC(Me)N(Dipp) (Dipp(2)N(wedge)NH; Dipp = C(6)H(3)-2,6-Pr(i)(2)) with M[N(SiMe(3))(2)](2) (M = Mn or Co) gave Dipp(2)N(wedge)NMN(SiMe(3))(2) (M = Mn, 1; Co, 3) while the reaction of Fe[N(SiMe(3))(2)](2) with Ar(2)N(wedge)NH (Ar = Dipp, C(6)F(5), Mes, C(6)H(3)-2,6-Me(2), or C(6)H(3)-2,6-Cl(2)) afforded the series of iron complexes Ar(2)N(wedge)NFe[N(SiMe(3))(2)] (Ar = Dipp, 2a; C(6)F(5), 2b; Mes, 2c; C(6)H(3)-2,6-Me(2), 2d; C(6)H(3)-2,6-Cl(2), 2e). This represents a new synthetic route to beta-diketiminate complexes of these metals. The four-coordinate bis-beta-diketiminate complex Fe[N(wedge)N(C(6)F(5))(2)](2), 4, was also isolated as a byproduct from the synthesis of 2b. Direct reaction of the Dipp(2)N(wedge)NLi with CoCl(2) gave the "ate" salt Dipp(2)N(wedge)NCoCl(2)Li(THF)(2), 5, in which the lithium chloride has formed a complex with Dipp(2)N(wedge)NCoCl through chloride bridging. The Fe(III) species Dipp(2)N(wedge)NFeCl(2), 6, was obtained cleanly from the reaction of FeCl(3) with Dipp(2)N(wedge)NLi. Magnetic measurements showed that all the complexes have a high spin configuration. The different substituents in the series of iron complexes 2a-e allowed assignment of their paramagnetically shifted (1)H NMR spectra. The X-ray crystal structures 1-2d and 3 showed that they have a distorted three-coordinate planar configuration at the metals whereas complexes 4-6 have highly distorted four-coordinate geometries.

  18. 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.

  19. The Porphyromonas gingivalis HmuY haemophore binds gallium(iii), zinc(ii), cobalt(iii), manganese(iii), nickel(ii), and copper(ii) protoporphyrin IX but in a manner different to iron(iii) protoporphyrin IX.

    PubMed

    Wójtowicz, Halina; Bielecki, Marcin; Wojaczyński, Jacek; Olczak, Mariusz; Smalley, John W; Olczak, Teresa

    2013-04-01

    Porphyromonas gingivalis, a major etiological agent of chronic periodontitis, acquires haem from host haemoproteins through a haem transporter HmuR and a haemophore HmuY. The aim of this study was to analyse the binding specificity of HmuY towards non-iron metalloporphyrins which may be employed as antimicrobials to treat periodontitis. HmuY binds gallium(iii), zinc(ii), cobalt(iii), manganese(iii), nickel(ii), and copper(ii) protoporphyrin IX but in a manner different to iron(iii) protoporphyrin IX which uses His(134) and His(166) as axial ligands. The metal ions in Ga(iii)PPIX and Zn(ii)PPIX can accept only His(166) as an axial ligand, whereas nickel(ii) and copper(ii) interact exclusively with His(134). Two forms of pentacoordinate manganese(iii) are present in the Mn(iii)PPIX-HmuY complex since the metal accepts either His(134) or His(166) as a single axial ligand. The cobalt ion is hexacoordinate in the Co(iii)PPIX-HmuY complex and binds His(134) and His(166) as axial ligands; however, some differences in their environments exist. Despite different coordination modes of the central metal ion, gallium(iii), zinc(ii), cobalt(iii), and manganese(iii) protoporphyrin IX bound to the HmuY haemophore cannot be displaced by excess haem. All of the metalloporphyrins examined bind to a P. gingivalis wild-type strain with higher ability compared to a mutant strain lacking a functional hmuY gene, thus corroborating binding of non-iron metalloporphyrins to purified HmuY protein. Our results further clarify the basis of metalloporphyrin acquisition by P. gingivalis and add to understanding of the interactions with porphyrin derivatives which exhibit antimicrobial activity against P. gingivalis.

  20. Accumulation and distribution of iron, cadmium, lead and nickel in cucumber plants grown in hydroponics containing two different chelated iron supplies.

    PubMed

    Csog, Árpád; Mihucz, Victor G; Tatár, Eniko; Fodor, Ferenc; Virág, István; Majdik, Cornelia; Záray, Gyula

    2011-07-01

    Cucumber plants grown in hydroponics containing 10 μM Cd(II), Ni(II) and Pb(II), and iron supplied as Fe(III) EDTA or Fe(III) citrate in identical concentrations, were investigated by total-reflection X-ray fluorescence spectrometry with special emphasis on the determination of iron accumulation and distribution within the different plant compartments (root, stem, cotyledon and leaves). The extent of Cd, Ni and Pb accumulation and distribution were also determined. Generally, iron and heavy-metal contaminant accumulation was higher when Fe(III) citrate was used. The accumulation of nickel and lead was higher by about 20% and 100%, respectively, if the iron supply was Fe(III) citrate. The accumulation of Cd was similar. In the case of Fe(III) citrate, the total amounts of Fe taken up were similar in the control and heavy-metal-treated plants (27-31 μmol/plant). Further, the amounts of iron transported from the root towards the shoot of the control, lead- and nickel-contaminated plants were independent of the iron(III) form. Although Fe mobility could be characterized as being low, its distribution within the shoot was not significantly affected by the heavy metals investigated.

  1. Inactivation of tyrosine 3-monooxygenase by acetone precipitation and its restoration by incubation with a sulfhydryl agent and iron.

    PubMed

    Okuno, S; Fujisawa, H

    1981-04-14

    The acetone precipitation of a partially purified tyrosine 3-monooxygenase (L-tyrosine, tetrahydropteridine: oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2) resulted in the complete loss of enzymatic activity. The enzymatic activity was restored by incubation with iron and dithiothreitol. The restoration of the activity was a pH-, temperature- and time-dependent reaction. Since cobalt, nickel, copper, zinc, manganese, cadmium, magnesium calcium and barium ions were all ineffective in restoring activity, iron ion appeared to be specifically required in the restoration of the enzyme activity. Dithiothreitol could be partially replaced in the restoration step by glutathione, 2-mercaptoethanol or cysteine.

  2. Bispecific Antibody Conjugated Manganese-Based Magnetic Engineered Iron Oxide for Imaging of HER2/neu- and EGFR-Expressing Tumors.

    PubMed

    Wu, Shou-Cheng; Chen, Yu-Jen; Wang, Hsiang-Ching; Chou, Min-Yuan; Chang, Teng-Yuan; Yuan, Shyng-Shiou; Chen, Chiao-Yun; Hou, Ming-Feng; Hsu, John Tsu-An; Wang, Yun-Ming

    2016-01-01

    The overexpression of HER2/neu and EGFR receptors plays important roles in tumorigenesis and tumor progression. Targeting these two receptors simultaneously can have a more widespread application in early diagnosis of cancers. In this study, a new multifunctional nanoparticles (MnMEIO-CyTE777-(Bis)-mPEG NPs) comprising a manganese-doped iron oxide nanoparticle core (MnMEIO), a silane-amino functionalized poly(ethylene glycol) copolymer shell, a near infrared fluorescence dye (CyTE777), and a covalently conjugated anti-HER2/neu and anti-EGFR receptors bispecific antibody (Bis) were successfully developed. In vitro T2-weighted MR imaging studies in SKBR-3 and A431 tumor cells incubated with MnMEIO-CyTE777-(Bis)-mPEG NPs showed - 94.8 ± 3.8 and - 84.1 ± 2.8% negative contrast enhancement, respectively. Pharmacokinetics study showed that MnMEIO-CyTE777-(Bis)-mPEG NPs were eliminated from serum with the half-life of 21.3 mins. In vivo MR imaging showed that MnMEIO-CyTE777-(Bis)-mPEG NPs could specifically and effectively target to HER2/neu- and EGFR-expressing tumors in mice; the relative contrast enhancements were 11.8 (at 2 hrs post-injection) and 61.5 (at 24 hrs post-injection) fold higher in SKBR-3 tumors as compared to Colo-205 tumors. T2-weighted MR and optical imaging studies revealed that the new contrast agent (MnMEIO-CyTE777-(Bis)-mPEG NPs) could specifically and effectively target to HER2/neu- and/or EGFR-expressing tumors. Our results demonstrate that MnMEIO-CyTE777-(Bis)-mPEG NPs are able to recognize the tumors expressing both HER2/neu and/or EGFR, and may provide a novel molecular imaging tool for early diagnosis of cancers expressing HER2/neu and/or EGFR.

  3. Direct Synthesis of Novel and Reactive Sulfide-modified Nano Iron through Nanoparticle Seeding for Improved Cadmium-Contaminated Water Treatment

    PubMed Central

    Su, Yiming; Adeleye, Adeyemi S.; Huang, Yuxiong; Zhou, Xuefei; Keller, Arturo A.; Zhang, Yalei

    2016-01-01

    Magnetic sulfide-modified nanoscale zerovalent iron (S-nZVI) is of great technical and scientific interest because of its promising application in groundwater remediation, although its synthesis is still a challenge. We develop a new nanoparticle seeding method to obtain a novel and reactive nanohybrid, which contains an Fe(0) core covered by a highly sulfidized layer under high extent of sulfidation. Syntheses monitoring experiments show that seeding accelerates the reduction rate from Fe2+ to Fe0 by 19%. X-ray adsorption near edge structure (XANES) spectroscopy and extended X-ray absorption fine structure analyses demonstrate the hexahedral Fe-Fe bond (2.45 and 2.83 Å) formation through breaking down of the 1.99 Å Fe-O bond both in crystalline and amorphous iron oxide. The XANES analysis also shows 24.2% (wt%) of FeS with bond length of 2.4 Å in final nanohybrid. Both X-ray diffraction and Mössbauer analyses further confirm that increased nanoparticle seeding results in formation of more Fe0 crystals. Nano-SiO2 seeding brings down the size of single Fe0 grain from 32.4 nm to 18.7 nm, enhances final Fe0 content from 5.9% to 55.6%, and increases magnetization from 4.7 to 65.5 emu/g. The synthesized nanohybrid has high cadmium removal capacity and holds promising prospects for treatment of metal-contaminated water. PMID:27095387

  4. Simultaneous removal of cadmium and nitrate in aqueous media by nanoscale zerovalent iron (nZVI) and Au doped nZVI particles.

    PubMed

    Su, Yiming; Adeleye, Adeyemi S; Huang, Yuxiong; Sun, Xiaoya; Dai, Chaomeng; Zhou, Xuefei; Zhang, Yalei; Keller, Arturo A

    2014-10-15

    Nanoscale zerovalent iron (nZVI) has demonstrated high efficacy for treating nitrate or cadmium (Cd) contamination, but its efficiency for simultaneous removal of nitrate and Cd has not been investigated. This study evaluated the reactivity of nZVI to the co-contaminants and by-product formation, employed different catalysts to reduce nitrite yield from nitrate, and examined the transformation of nZVI after reaction. Nitrate reduction resulted in high solution pH, negatively charged surface of nZVI, formation of Fe3O4 (a stable transformation of nZVI), and no release of ionic iron. Increased pH and negative charge contributed to significant increase in Cd(II) removal capacity (from 40 mg/g to 188 mg/g) with nitrate present. In addition, nitrate reduction by nZVI could be catalyzed by Cd(II): while 30% of nitrate was reduced by nZVI within 2 h in the absence of Cd(II), complete nitrate reduction was observed in the presence of 40 mg-Cd/L due to the formation of Cd islands (Cd(0) and CdO) on the nZVI particles. While nitrate was reduced mostly to ammonium when Cd(II) was not present or at Cd(II) concentrations ≥ 40 mg/L, up to 20% of the initial nitrate was reduced to nitrite at Cd(II) concentrations < 40 mg/L. Among nZVI particles doped with 1 wt. % Cu, Ag, or Au, nZVI deposited with 1 wt. % Au reduced nitrite yield to less than 3% of the initial nitrate, while maintaining a high Cd(II) removal capacity.

  5. Manganese concentrations in soil and settled dust in an area with historic ferroalloy production

    PubMed Central

    Pavilonis, Brian T.; Lioy, Paul J.; Guazzetti, Stefano; Bostick, Benjamin C.; Donna, Filippo; Peli, Marco; Zimmerman, Neil J.; Bertrand, Patrick; Lucas, Erika; Smith, Donald R.; Georgopoulos, Panos G.; Mi, Zhongyuan; Royce, Steven G.; Lucchini, Roberto G.

    2015-01-01

    Ferroalloy production can release a number of metals into the environment, of which manganese (Mn) is of major concern. Other elements include lead, iron, zinc, copper, chromium, and cadmium. Manganese exposure derived from settled dust and suspended aerosols can cause a variety of adverse neurological effects to chronically exposed individuals. To better estimate the current levels of exposure, this study quantified metal levels in dust collected inside homes (n=85), outside homes (n=81), in attics (n=6), and in surface soil (n=252) in an area with historic ferroalloy production. Metals contained in indoor and outdoor dust samples were quantified using inductively coupled plasma optical emission spectroscopy while attic and soil measurements were made with a XRF instrument. Mean Mn concentrations in soil (4600 μg/g) and indoor dust (870 μg/g) collected within 0.5 km of a plant exceeded levels previously found in suburban and urban areas, but did decrease outside 1.0 km to the upper end of background concentrations. Mn concentrations in attic dust were approximately 120 times larger than other indoor dust levels, consistent with historical emissions that yielded high airborne concentrations in the region. Considering the potential health effects that are associated with chronic manganese inhalation and ingestion exposure, remediation of soil near the plants and frequent, on-going hygiene indoors may decrease residential exposure and the likelihood of adverse health effects. PMID:25335867

  6. Possible Relationship between Chronic Telogen Effluvium and Changes in Lead, Cadmium, Zinc, and Iron Total Blood Levels in Females: A Case-Control Study

    PubMed Central

    Abdel Aziz, Abeer M; Sh Hamed, Sameera; Gaballah, Mohammad A

    2015-01-01

    Introduction: Hair loss is a common and distressing problem that can affect both males and females of all ages. Chronic telogen effluvium (CTE) is idiopathic diffuse scalp hair shedding of at least 6 months duration. Hair loss can be one of the symptoms of metal toxicity. Lead (Pb) and cadmium (Cd) are highly toxic metals that can cause acute and chronic health problems in human. The aim of the present study is to determine if there is a relationship between these metals and CTE in women and if CTE is also associated with changes in zinc (Zn) or iron (Fe) blood levels. Materials and Methods: Pb, Cd, Fe and Zn total blood levels were determined in 40 female patients fulfilling the criteria of CTH and compared with total blood levels of same elements in 30 well-matched healthy women. Results: Quantitative analysis of total blood Fe, Zn, Pb and Cd revealed that there were no significant differences between patients and controls regarding Fe, Zn, and Pb. Yet, Cd level was significantly higher in patients than controls. In addition, Cd level showed significant positive correlation with the patient's body weight. Conclusion: Estimation of blood Pb and Cd levels can be important in cases of CTE as Cd toxicity can be the underlying hidden cause of such idiopathic condition. PMID:26622152

  7. Stress hardening under long-term cadmium treatment is correlated with the activation of antioxidative defence and iron acquisition of chloroplasts in Populus.

    PubMed

    Solti, Ádám; Sárvári, Éva; Szöllősi, Erzsébet; Tóth, Brigitta; Mészáros, Ilona; Fodor, Ferenc; Szigeti, Zoltán

    2016-09-01

    Cadmium (Cd), a highly toxic heavy metal affects growth and metabolic pathways in plants, including photosynthesis. Though Cd is a transition metal with no redox capacity, it generates reactive oxygen species (ROS) indirectly and causes oxidative stress. Nevertheless, the mechanisms involved in long-term Cd tolerance of poplar, candidate for Cd phytoremediation, are not well known. Hydroponically cultured poplar (Populus jacquemontiana var. glauca cv. 'Kopeczkii') plants were treated with 10 μM Cd for 4 weeks. Following a period of functional decline, the plants performed acclimation to the Cd induced oxidative stress as indicated by the decreased leaf malondialdehyde (MDA) content and the recovery of most photosynthetic parameters. The increased activity of peroxidases (PODs) could have a great impact on the elimination of hydrogen peroxide, and thus the recovery of photosynthesis, while the function of superoxide dismutase (SOD) isoforms seemed to be less important. Re-distribution of the iron content of leaf mesophyll cells into the chloroplasts contributed to the biosynthesis of the photosynthetic apparatus and some antioxidative enzymes. The delayed increase in photosynthetic activity in relation to the decline in the level of lipid peroxidation indicates that elimination of oxidative stress damage by acclimation mechanisms is required for the restoration of the photosynthetic apparatus during long-term Cd treatment.

  8. Comparison on cellular mechanisms of iron and cadmium accumulation in rice: prospects for cultivating Fe-rich but Cd-free rice.

    PubMed

    Gao, Lei; Chang, Jiadong; Chen, Ruijie; Li, Hubo; Lu, Hongfei; Tao, Longxing; Xiong, Jie

    2016-12-01

    Iron (Fe) is essential for rice growth and humans consuming as their staple food but is often deficient because of insoluble Fe(III) in soil for rice growth and limited assimilation for human bodies, while cadmium (Cd) is non-essential and toxic for rice growth and humans if accumulating at high levels. Over-accumulated Cd can cause damage to human bodies. Selecting and breeding Fe-rich but Cd-free rice cultivars are ambitious, challenging and meaningful tasks for researchers. Although evidences show that the mechanisms of Fe/Cd uptake and accumulation in rice are common to some extent as a result of similar entry routes within rice, an increasing number of researchers have discovered distinct mechanisms between Fe/Cd uptake and accumulation in rice. This comprehensive review systematically elaborates and compares cellular mechanisms of Fe/Cd uptake and accumulation in rice, respectively. Mechanisms for maintaining Fe homeostasis and Cd detoxicification are also elucidated. Then, effects of different fertilizer management on Fe/Cd accumulation in rice are discussed. Finally, this review enumerates various approaches for reducing grain Cd accumulation and enhancing Fe content in rice. In summary, understanding of discrepant cellular mechanisms of Fe/Cd accumulation in rice provides guidance for cultivating Fe-fortified rice and has paved the way to develop rice that are tolerant to Cd stress, aiming at breeding Fe-rich but Cd-free rice.

  9. Operative photo assimilation associated proteome modulations are critical for iron-dependent cadmium tolerance in Oryza sativa L.

    PubMed

    Sebastian, Abin; Prasad, M N V

    2015-09-01

    Iron-dependent Cd tolerance in Oryza sativa L. cv 7029 had been explored. Photo assimilatory process such as photosynthesis and nitrogen fixation found to be functional in the presence of excess Fe during Cd stress. Cd-inducible Fe deficiency demonstrated with upregulation of iron uptake gene families such as OsIRT and OsYSL was attributed as foremost reason for retardation of photo assimilation in the course of Cd treatment. Upholding of photo assimilation during Fe supplement was associated with proteome modulations. Monitoring of proteome responses in leaf and root revealed proteins imperative for alleviation of Cd stress. Specifically, proteins that take part in photosynthesis, glucose metabolism, nitrogen fixation, and abiotic stress tolerance played key role in Fe-dependent Cd detoxification. It is concluded that Fe supply help to operate photo assimilation which enable favorable proteome responses of Cd stress tolerance.

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

    DOEpatents

    Maziasz, Philip J.; Paris, Alan M.; Vought, Joseph D.

    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.

  11. Relation of arsenic, iron, and manganese in ground water to aquifer type, bedrock lithogeochemistry, and land use in the New England coastal basins

    USGS Publications Warehouse

    Ayotte, Joseph D.; Nielsen, Martha G.; Robinson,, Gilpin R.; Moore, Richard B.

    1999-01-01

    In a study of arsenic concentrations in public-supply wells in the New England Coastal Basins, concentrations at or above 0.005 mg/L (milligrams per liter) were detected in more samples of water from wells completed in bedrock (25 percent of all samples) than in water from wells completed in stratified drift (7.5 percent of all samples). Iron and manganese were detected (at concentrations of 0.05 and 0.03 mg/L, respectively) at approximately the same frequency in water from wells in both types of aquifers. Concentrations of arsenic in public-supply wells drilled in bedrock (in the National Water-Quality Assessment Program New England Coastal Basins study unit) vary with the bedrock lithology. Broad groups of lithogeochemical units generalized from bedrock lithologic units shown on state geologic maps were used in the statistical analyses. Concentrations of arsenic in water from public-supply wells in metasedimentary bedrock units that contain slightly to moderately calcareous and calcsilicate rocks (lithogeochemical group Mc) were significantly higher than the concentrations in five other groups of bedrock units in the study unit. Arsenic was detected, at or above 0.005 mg/L, in water from 44 percent of the wells in the lithogeochemical group M c and in water from less than 28 percent of wells in the five other groups. Additionally, arsenic concentrations in ground water were the lowest in the metasedimentary rocks that are characterized as variably sulfidic (group Ms ). Generally, concentrations of arsenic were low in water from bedrock wells in the felsic igneous rocks (group If ) though locally some bedrock wells in granitic rocks are known to have ground water with high arsenic concentrations, especially in New Hampshire. The concentrations of arsenic in ground water also correlate with land-use data; significantly higher concentrations are found in areas identified as agricultural land use than in undeveloped areas. There is, however, more agricultural land in

  12. 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

  13. Inhibitory effect of dissolved silica on H₂O₂ decomposition by iron(III) and manganese(IV) oxides: implications for H₂O₂-based in situ chemical oxidation.

    PubMed

    Pham, Anh Le-Tuan; Doyle, Fiona M; Sedlak, David L

    2012-01-17

    The decomposition of H(2)O(2) on iron minerals can generate •OH, a strong oxidant that can transform a wide range of contaminants. This reaction is critical to In Situ Chemical Oxidation (ISCO) processes used for soil and groundwater remediation, as well as advanced oxidation processes employed in waste treatment systems. The presence of dissolved silica at concentrations comparable to those encountered in natural waters decreases the reactivity of iron minerals toward H(2)O(2), because silica adsorbs onto the surface of iron minerals and alters catalytic sites. At circumneutral pH values, goethite, amorphous iron oxide, hematite, iron-coated sand, and montmorillonite that were pre-equilibrated with 0.05-1.5 mM SiO(2) were significantly less reactive toward H(2)O(2) decomposition than their original counterparts, with the H(2)O(2) loss rates inversely proportional to SiO(2) concentrations. In the goethite/H(2)O(2) system, the overall •OH yield, defined as the percentage of decomposed H(2)O(2) producing •OH, was almost halved in the presence of 1.5 mM SiO(2). Dissolved SiO(2) also slowed H(2)O(2) decomposition on manganese(IV) oxide. The presence of dissolved SiO(2) results in greater persistence of H(2)O(2) in groundwater and lower H(2)O(2) utilization efficiency and should be considered in the design of H(2)O(2)-based treatment systems.

  14. A binary A(x)B(1-x) ionic alkaline pseudocapacitor system involving manganese, iron, cobalt, and nickel: formation of electroactive colloids via in situ electric field assisted coprecipitation.

    PubMed

    Chen, Kunfeng; Yin, Shu; Xue, Dongfeng

    2015-01-21

    A new "combinatorial transition-metal cation pseudocapacitor" was demonstrated by designing combinatorial transition-metal cation pseudocapacitors with binary AxB1-x salt electrodes involving manganese, iron, cobalt, and nickel cations in an alkaline aqueous electrolyte. Binary multi-valence cations were crystallized in the colloidal state through an in situ coprecipitation under an electric field. These electroactive colloids absorbed by carbon black and the PVDF matrix are highly redox-reactive with high specific capacitance values, where the specific electrode configuration can create short ion diffusion paths to enable fast and reversible Faradaic reactions. This work shows huge promise for developing high-performance electrical energy storage systems via designing the colloidal state of electroactive cations. Multiple redox cations in the colloidal state can show high redox activities, making them more suitable for potential application in pseudocapacitor systems.

  15. Cadmium availability in rice paddy fields from a mining area: The effects of soil properties highlighting iron fractions and pH value.

    PubMed

    Yu, Huan-Yun; Liu, Chuanping; Zhu, Jishu; Li, Fangbai; Deng, Dong-Mei; Wang, Qi; Liu, Chengshuai

    2016-02-01

    Cadmium (Cd) availability can be significantly affected by soil properties. The effect of pH value on Cd availability has been confirmed. Paddy soils in South China generally contain high contents of iron (Fe). Thus, it is hypothesized that Fe fractions, in addition to pH value, may play an important role in the Cd bioavailability in paddy soil and this requires further investigation. In this study, 73 paired soil and rice plant samples were collected from paddy fields those were contaminated by acid mine drainage containing Cd. The contents of Fe in the amorphous and DCB-extractable Fe oxides were significantly and negatively correlated with the Cd content in rice grain or straw (excluding DCB-extractable Fe vs Cd in straw). In addition, the concentration of HCl-extractable Fe(II) derived from Fe(III) reduction was positively correlated with the Cd content in rice grain or straw. These results suggest that soil Fe redox could affect the availability of Cd in rice plant. Contribution assessment of soil properties to Cd accumulation in rice grain based on random forest (RF) and stochastic gradient boosting (SGB) showed that pH value should be the most important factor and the content of Fe in the amorphous Fe oxides should be the second most important factor in affecting Cd content in rice grain. Overall, compared with the studies from temperate regions, such as Europe and northern China, Fe oxide exhibited its unique role in the bioavailability of Cd in the reddish paddy soil from our study area. The exploration of practical remediation strategies for Cd from the perspective of Fe oxide may be promising.

  16. Manganese nodules

    USGS Publications Warehouse

    Hein, James R.; Harff, Jan; Petersen, Sven; Thiede, Jorn

    2016-01-01

    The existence of manganese (Mn) nodules (Fig. 1) has been known since the late 1800s when they were collected during the Challenger expedition of 1873–1876. However, it was not until after WWII that nodules were further studied in detail for their ability to adsorb metals from seawater. Many of the early studies did not distinguish Mn nodules from Mn crusts. Economic interest in Mn nodules began in the late 1950s and early 1960s when John Mero finished his Ph.D. thesis on this subject, which was published...

  17. 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

  18. Manganese concentrate usage in steelmaking

    NASA Astrophysics Data System (ADS)

    Nokhrina, O. I.; Rozhihina, I. D.

    2015-09-01

    The results of the research process of producing metalized products by solid-phase reduction of iron using solid carbonaceous reducing agents. Thermodynamic modeling was carried out on the model of the unit the Fe-C-O and system with iron ore and coal. As a result of modeling the thermodynamic boundary reducing, oxidizing, and transition areas and the value of the ratio of carbon and oxygen in the system. Simulation of real systems carried out with the gas phase obtained in the pyrolys of coal. The simulation results allow to determine the optimal cost of coal required for complete reduction of iron ore from a given composition. The kinetics of the processes of solid-phase reduction of iron using coal of various technological brands. The paper describes experiments on effects of metal deoxidizer composition, component proportion, pelletizing mixture, particle size distribution of basic materials and flux on manganese recovering from oxides under direct melting.

  19. Impact of two iron(III) chelators on the iron, cadmium, lead and nickel accumulation in poplar grown under heavy metal stress in hydroponics.

    PubMed

    Mihucz, Victor G; Csog, Árpád; Fodor, Ferenc; Tatár, Enikő; Szoboszlai, Norbert; Silaghi-Dumitrescu, Luminiţa; Záray, Gyula

    2012-04-15

    Poplar (Populus jacquemontiana var. glauca cv. Kopeczkii) was grown in hydroponics containing 10 μM Cd(II), Ni(II) or Pb(II), and Fe as Fe(III) EDTA or Fe(III) citrate in identical concentrations. The present study was designed to compare the accumulation and distribution of Fe, Cd, Ni and Pb within the different plant compartments. Generally, Fe and heavy-metal accumulation were higher by factor 2-7 and 1.6-3.3, respectively, when Fe(III) citrate was used. Iron transport towards the shoot depended on the Fe(III) chelate and, generally, on the heavy metal used. Lead was accumulated only in the root. The amounts of Fe and heavy metals accumulated by poplar were very similar to those of cucumber grown in an identical way, indicating strong Fe uptake regulation of these two Strategy I plants: a cultivar and a woody plant. The Strategy I Fe uptake mechanism (i.e. reducing Fe(III) followed by Fe(II) uptake), together with the Fe(III) chelate form in the nutrient solution had significant effects on Fe and heavy metal uptake. Poplar appears to show phytoremediation potential for Cd and Ni, as their transport towards the shoot was characterized by 51-54% and 26-48% depending on the Fe(III) supply in the nutrient solution.

  20. Cadmium toxicity

    PubMed Central

    Wan, Lichuan; Zhang, Haiyan

    2012-01-01

    Cadmium is a well-known environmental pollutant with distinctly toxic effects on plants. It can displace certain essential metals from a wealth of metalloproteins, and thus disturb many normal physiological processes and cause severe developmental aberrant. The harmful effects of cadmium stress include, but are not limited to: reactive oxygen species overproduction, higher lipid hydroperoxide contents, and chloroplast structure change, which may lead to cell death. Plants have developed diverse mechanisms to alleviate environmental cadmium stress, e.g., cadmium pump and transporting cadmium into the leaf vacuoles. This mini-review focuses on the current research into understanding the cellular mechanisms of cadmium toxicity on cytoskeleton, vesicular trafficking and cell wall formation in plants. PMID:22499203

  1. Cadmium Alternatives

    DTIC Science & Technology

    2012-08-01

    including cadmium! Cadmium Replacements (With MIL-DTL-38999 Designations) Zn/Ni (Class Z) Per ASTM B 841, type D (black) Electroless Nickel plus... Electroless nickel / PTFE (Durmalon®) Electroplated Aluminum (Alumiplate®) Electroplated tin-zinc (SnZn) Control: cadmium with hexavalent chromate... electroless nickel / PTFE performed well Electroplated aluminum performed did not perform well on connectors Electroplated aluminum did not

  2. Dysregulation of transition metal ion homeostasis is the molecular basis for cadmium toxicity in Streptococcus pneumoniae

    PubMed Central

    Begg, Stephanie L.; Eijkelkamp, Bart A.; Luo, Zhenyao; Couñago, Rafael M.; Morey, Jacqueline R.; Maher, Megan J.; Ong, Cheryl-lynn Y.; McEwan, Alastair G.; Kobe, Bostjan; O’Mara, Megan L.; Paton, James C.; McDevitt, Christopher A.

    2015-01-01

    Cadmium is a transition metal ion that is highly toxic in biological systems. Although relatively rare in the Earth’s crust, anthropogenic release of cadmium since industrialization has increased biogeochemical cycling and the abundance of the ion in the biosphere. Despite this, the molecular basis of its toxicity remains unclear. Here we combine metal-accumulation assays, high-resolution structural data and biochemical analyses to show that cadmium toxicity, in Streptococcus pneumoniae, occurs via perturbation of first row transition metal ion homeostasis. We show that cadmium uptake reduces the millimolar cellular accumulation of manganese and zinc, and thereby increases sensitivity to oxidative stress. Despite this, high cellular concentrations of cadmium (~17 mM) are tolerated, with negligible impact on growth or sensitivity to oxidative stress, when manganese and glutathione are abundant. Collectively, this work provides insight into the molecular basis of cadmium toxicity in prokaryotes, and the connection between cadmium accumulation and oxidative stress. PMID:25731976

  3. Improved Manganese Phosphate Coatings

    DTIC Science & Technology

    1975-04-01

    Conversion coatings 3 . Phosphating bath 20 AGrjC onln odd*. ta It .. c..soMV midP 1J.,alft. by block noc.mb) Work was conducted to determine the mechanism by...34 TABULAR DATA Table I Analyses of Solution and Coating for Phosphating Baths 4 of Di-ferlng Compositions 11 Atomic Absorption...manganese and iron phosphate coating: k * a. Mn(H 2PO4) 2 Nn-P0 4 + H3PO0 k2 k) b. 3MnHPO4 - Mn3 (P04) 2 + H3i’O4 k4 k5 c. Fe(H 2PO4) 2 -01 FeHPO4

  4. Ecological risk assessment of on-site soil washing with iron(III) chloride in cadmium-contaminated paddy field.

    PubMed

    Nagai, Takashi; Horio, Takeshi; Yokoyama, Atsushi; Kamiya, Takashi; Takano, Hiroyuki; Makino, Tomoyuki

    2012-06-01

    On-site soil washing with iron(III) chloride reduces Cd levels in soil, and thus the human health risks caused by Cd in food. However, it may threaten aquatic organisms when soil washing effluent is discharged to open aquatic systems. Therefore, we conducted trial-scale on-site soil washing and ecological risk assessment in Nagano and Niigata prefectures, Japan. The ecological effect of effluent water was investigated by two methods. The first was bioassay using standard aquatic test organisms. Twice-diluted effluent water from the Nagano site and the original effluent water from the Niigata site had no significant effects on green algae, water flea, caddisfly, and fish. The safe dilution rates were estimated as 20 times and 10 times for the Nagano and Niigata sites, respectively, considering an assessment factor of 10. The second method was probabilistic effect analysis using chemical analysis and the species sensitivity distribution concept. The mixture effects of CaCl(2), Al, Zn, and Mn were considered by applying a response additive model. The safe dilution rates, assessed for a potentially affected fraction of species of 5%, were 7.1 times and 23.6 times for the Nagano and Niigata sites, respectively. The actual dilution rates of effluent water by river water at the Nagano and Niigata sites were 2200-67,000 times and 1300-110,000 times, respectively. These are much larger than the safe dilution rates derived from the two approaches. Consequently, the ecological risk to aquatic organisms of soil washing is evaluated as being below the concern level.

  5. Spectroscopic characterization of manganese minerals.

    PubMed

    Lakshmi Reddy, S; Padma Suvarna, K; Udayabhaska Reddy, G; Endo, Tamio; Frost, R L

    2014-01-03

    Manganese minerals ardenite, alleghanyite and leucopoenicite originated from Madhya Pradesh, India, Nagano prefecture Japan, Sussex Country and Parker Shaft Franklin, Sussex Country, New Jersey respectively are used in the present work. In these minerals manganese is the major constituent and iron if present is in traces only. An EPR study of on all of the above samples confirms the presence of Mn(II) with g around 2.0. Optical absorption spectrum of the mineral alleghanyite indicates that Mn(II) is present in two different octahedral sites and in leucophoenicite Mn(II) is also in octahedral geometry. Ardenite mineral gives only a few Mn(II) bands. NIR results of the minerals ardenite, leucophoenicite and alleghanyite are due to hydroxyl and silicate anions which confirming the formulae of the minerals.

  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. )

    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. Real-Time Manganese Phase Dynamics during Biological and Abiotic Manganese Oxide Reduction.

    PubMed

    Johnson, Jena E; Savalia, Pratixa; Davis, Ryan; Kocar, Benjamin D; Webb, Samuel M; Nealson, Kenneth H; Fischer, Woodward W

    2016-04-19

    Manganese oxides are often highly reactive and easily reduced, both abiotically, by a variety of inorganic chemical species, and biologically during anaerobic respiration by microbes. To evaluate the reaction mechanisms of these different reduction routes and their potential lasting products, we measured the sequence progression of microbial manganese(IV) oxide reduction mediated by chemical species (sulfide and ferrous iron) and the common metal-reducing microbe Shewanella oneidensis MR-1 under several endmember conditions, using synchrotron X-ray spectroscopic measurements complemented by X-ray diffraction and Raman spectroscopy on precipitates collected throughout the reaction. Crystalline or potentially long-lived phases produced in these experiments included manganese(II)-phosphate, manganese(II)-carbonate, and manganese(III)-oxyhydroxides. Major controls on the formation of these discrete phases were alkalinity production and solution conditions such as inorganic carbon and phosphate availability. The formation of a long-lived Mn(III) oxide appears to depend on aqueous Mn(2+) production and the relative proportion of electron donors and electron acceptors in the system. These real-time measurements identify mineralogical products during Mn(IV) oxide reduction, contribute to understanding the mechanism of various Mn(IV) oxide reduction pathways, and assist in interpreting the processes occurring actively in manganese-rich environments and recorded in the geologic record of manganese-rich strata.

  8. Determination of calcium, copper, iron, magnesium, manganese, potassium, phosphorus, sodium, and zinc in fortified food products by microwave digestion and inductively coupled plasma-optical emission spectrometry: single-laboratory validation and ring trial.

    PubMed

    Poitevin, Eric

    2012-01-01

    A single-laboratory validation (SLV) and a ring trial (RT) were undertaken to determine nine nutritional elements in food products by inductively coupled plasma-optical emission spectrometry in order to modernize AOAC Official Method 984.27. The improvements involved extension of the scope to all food matrixes (including infant formula), optimized microwave digestion, selected analytical lines, internal standardization, and ion buffering. Simultaneous determination of nine elements (calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, and zinc) was made in food products. Sample digestion was performed through wet digestion of food samples by microwave technology with either closed- or open-vessel systems. Validation was performed to characterize the method for selectivity, sensitivity, linearity, accuracy, precision, recovery, ruggedness, and uncertainty. The robustness and efficiency of this method was proven through a successful RT using experienced independent food industry laboratories. Performance characteristics are reported for 13 certified and in-house reference materials, populating the AOAC triangle food sectors, which fulfilled AOAC criteria and recommendations for accuracy (trueness, recovery, and z-scores) and precision (repeatability and reproducibility RSD, and HorRat values) regarding SLVs and RTs. This multielemental method is cost-efficient, time-saving, accurate, and fit-for-purpose according to ISO 17025 Norm and AOAC acceptability criteria, and is proposed as an extended updated version of AOAC Official Method 984.27 for fortified food products, including infant formula.

  9. Solid phase extraction of trace amounts of cadmium(II) ions in water and food samples using iron magnetite nanoparticles modified by sodium dodecyl sulfate and 2-mercaptobenzothiazole.

    PubMed

    Abbasi, Shahriar; ShanbehDehbalai, Mehdi; Khani, Hossein

    2017-03-01

    A new, simple and rapid method for solid phase extraction and preconcentration of trace amounts of cadmium ions using 2-mercaptobenzothiazole/sodium dodecyl sulfate immobilized on magnetite nanoparticles (MBT-SDS-MNPs) was proposed. The method is based on the extraction of cadmium ions via complexation with MBT immobilized on SDS-coated MNPs and their determination by flame atomic absorption spectrometry. The effects of different parameters - pH; eluent type, concentration and volume; amounts of salt and adsorbent; contact time and interfering ions - on the adsorption of cadmium ions were studied. Under optimized conditions, the calibration curve was linear in the range of 10-5,000 μg L(-1). Detection limit and relative standard deviation of the proposed method were 0.009 μg L(-1) and 2.2%, respectively. The adsorption data were analyzed by Langmuir and Freundlich isotherm models and a maximum adsorption amount of 24.80 mg g(-1), a Langmuir adsorption equilibrium constant (b) of 4.62 and Freundlich constants Kf and n of 6.075 mg(1-1/n) L(1/n) g(-1) and 2.391, respectively, were obtained. Finally, this adsorbent was successfully used for extraction of cadmium from water and food samples.

  10. 210Pb and 210Po, manganese and iron cycling across the O2/H2S interface of a permanently anoxic fjord: Framvaren, Norway

    USGS Publications Warehouse

    Swarzenski, Peter W.; McKee, Brent A.; Sorenson, Kai; Todd, James F.

    1999-01-01

    Vertical profiles of dissolved and particulate 201Po and 210Pb were measured across the redox transition zone at Station F1 in Framvaren Fjord, Norway. In this fjord, a sharp decrease in pH above the O2/H2S interface facilitates the aerobic dissolution of MnO2. In contrast, Fe(II) concentrations begin to increase only at the O2/H2S interface depth. Activity profiles reveal that dissolved 210Po and 210Pb are sequestered efficiently by particulates in surface waters. As polonium-210 and lead-210 activities descend down into the aerobic manganese reduction (AMR) zone, they are remobilized during the reductive dissolution of the carrier phase oxyhydroxides. Both 210Po and 210Pb are highly enriched at the O2/H2S interface where an active community of microbes, such as anoxygenic phototrophs (e.g., Chromatium, Chlorobium sp.), thrives. The coincident peaks in 210Po and 210Pb and microbial biomass suggest a strong biological influence on the behavior of these radionuclides. There is a strong covariance between the vertical distribution of Mn and Pb, indicating that their redox cycling is closely coupled and is likely microbially mediated.

  11. 210Pb and 210Po, manganese and iron cycling across the O2/H2S interface of a permanently anoxic fjord: Framvaren, Norway

    USGS Publications Warehouse

    Swarzenski, Peter W.; McKee, Brent A.; Sorensen, Kai; Todd, James F.

    1999-01-01

    Vertical profiles of dissolved and particulate 210Po and 210b were measured across the redox transition zone at Station F1 in Framvaren Fjord, Norway. In this fjord, a sharp decrease in pH above the O2/H2S interface facilitates the aerobic dissolution of MnO2. In contrast, Fe(II) concentrations begin to increase only at the O2/H2S interface depth. Activity profiles reveal that dissolved 210Po and 210Pb are sequestered efficiently by particulates in surface waters. As polonium-210 and lead-210 activities descend down into the aerobic manganese reduction (AMR) zone, they are remobilized during the reductive dissolution of the carrier phase oxyhydroxides. Both 210Po and 210Pb are highly enriched at the O2/H2S interface where an active community of microbes, such as anoxygenic phototrophs (e.g., Chromatium, Chlorobium sp.), thrives. The coincident peaks in 210Po, 210Pb and microbial biomass suggest a strong biological influence on the behavior of these radionuclides. There is a strong covariance between the vertical distribution of Mn and Pb, indicating that their redox cycling is closely coupled and is likely microbially mediated.

  12. Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria.

    PubMed

    Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W; Loy, Alexander; Thamdrup, Bo

    2012-11-01

    Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the prevailing terminal electron-accepting process in anoxic incubations of surface sediments, and even the addition of acetate stimulated neither iron nor sulfate reduction. The three geographically distinct sediments harbored surprisingly similar communities of acetate-utilizing manganese-reducing bacteria: 16S rRNA of members of the genera Colwellia and Arcobacter and of novel genera within the Oceanospirillaceae and Alteromonadales were detected in heavy RNA-SIP fractions from these three sediments. Most probable number (MPN) analysis yielded up to 10(6) acetate-utilizing manganese-reducing cells cm(-3) in Gullmar Fjord sediment. A 16S rRNA gene clone library that was established from the highest MPN dilutions was dominated by sequences of Colwellia and Arcobacter species and members of the Oceanospirillaceae, supporting the obtained RNA-SIP results. In conclusion, these findings strongly suggest that (i) acetate-dependent manganese reduction in manganese oxide-rich sediments is catalyzed by members of taxa (Arcobacter, Colwellia and Oceanospirillaceae) previously not known to possess this physiological function, (ii) similar acetate-utilizing manganese reducers thrive in geographically distinct regions and (iii) the identified manganese reducers differ greatly from the extensively explored iron reducers in marine sediments.

  13. Electrochemical iron generation: The ideal process for simultaneous removal of heavy metals from contaminated groundwater

    SciTech Connect

    Brewster, M.D.

    1993-12-31

    At most Superfund sites, many heavy metals must be removed from contaminated groundwater. Simultaneous extraction is complicated due to the various chemical properties that metals exhibit. A comprehensive understanding of solubilities, oxidation states, and adsorptive mechanisms is needed to accomplish treatment objectives. This paper uses data from treatability tests conducted on groundwater from the King of Prussia Technical Corporation Site to discuss the electrochemical iron generation process developed by Andco Environmental Processes, Inc. Electrical current and sacrificial steel electrodes were used to put ferrous ions into solution. The chemistry was properly manipulated to provide adsorption and coprecipitation conditions capable of simultaneously removing beryllium, cadmium, chromium, copper, iron, manganese, mercury, nickel, and zinc. Strict cleanup levels were required since the site is located within Pinelands National Reserve and adjacent to New Jersey`s Winslow Wildlife Refuge. System design, operating costs, and sludge production rate are also discussed.

  14. On the effect of silicon and phosphorus during the precipitation of kappa-carbide in Iron-Manganese-Aluminium-Carbon alloys

    NASA Astrophysics Data System (ADS)

    Bartlett, Laura Nicole

    Implementation of lightweight high manganese and aluminum steels for use in high energy absorbing applications requires a detailed knowledge of how alloying additions and impurities affect age hardening and high strain rate fracture properties. Dynamic fracture toughness is an important design criterion but has not been reported previously in these alloys. In addition, previous studies have shown that silicon and phosphorus increased the strength and aged hardness; however, the mechanism was unknown. This research mainly focuses on the effect of silicon and phosphorus on the precipitation of kappa-carbide and alloy partitioning during aging. Short range ordering, SRO, of Fe-Al-C into relative atomic positions described by the E21 superlattice structure preceded and occurred concurrent to spinodal decomposition. Short range diffusion of phosphorus increased the kinetics of ordering resulting in a decrease in the time required for subsequent spinodal decomposition and an increase the amplitude of carbon concentration with time. Silicon increased the strength and hardness as a result of increased carbon partitioning into the kappa-carbide during aging. Dynamic fracture toughness was found to depend upon aluminum and carbon. Increasing the amount of solid solution carbon increased the dynamic fracture toughness in solution treated specimens. However, increasing carbon in aged specimens increased the amount of kappa-carbide and produced brittle fracture. Additions of aluminum from three to nine weight percent decreased toughness regardless of the heat treatment. Dynamic fracture toughness was a strong function of AlN content. A good combination of high strength and dynamic toughness with a corresponding density reduction of 10 to 12% is obtained with aluminum additions between 6 and 7% and carbon below 1.2%.

  15. 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.

  16. Manganese import is a key element of the OxyR response to hydrogen peroxide in Escherichia coli

    PubMed Central

    Anjem, Adil; Varghese, Shery; Imlay, James A.

    2009-01-01

    Very little manganese is imported into Escherichia coli under routine growth conditions: the import system is weakly expressed, the manganese content is low, and a manganese-dependent enzyme is not correctly metallated. Mutants that lack MntH, the importer, grow at wild-type rates, indicating that manganese plays no critical role. However, MntH supports the growth of iron-deficient cells, suggesting that manganese can substitute for iron in activating at least some metalloenzymes. MntH is also strongly induced when cells are stressed by hydrogen peroxide. This adaptation is essential, as E. coli cannot tolerate peroxide stress if mntH is deleted. Other workers have observed that manganese improves the ability of a variety of microbes to tolerate oxidative stress, and the prevailing hypothesis is that manganese does so by chemically scavenging hydrogen peroxide and/or superoxide. We found that manganese does not protect peroxide-stressed cells by scavenging peroxide. Instead, the beneficial effects of manganese correlate with its ability to metallate mononuclear enzymes. Because iron-loaded enzymes are vulnerable to the Fenton reaction, the substitution of manganese may prevent protein damage. Accordingly, during H2O2 stress, mutants that cannot import manganese and/or are unable to sequester iron suffer high rates of protein oxidation. PMID:19400769

  17. Manganese uptake of imprinted polymers

    SciTech Connect

    Susanna Ventura

    2015-09-30

    Batch tests of manganese imprinted polymers of variable composition to assess their ability to extract lithium and manganese from synthetic brines at T=45C . Data on manganese uptake for two consecutive cycles are included.

  18. Hydrolysis of an organophosphate ester by manganese dioxide.

    PubMed

    Baldwin, D S; Beattie, J K; Coleman, L M; Jones, D R

    2001-02-15

    Amorphous manganese dioxide facilitates the hydrolysis of p-nitrophenyl phosphate to p-nitrophenol and orthophosphate despite insignificant adsorption of p-nitrophenyl phosphate or p-nitrophenol to the manganese dioxide. At pH 8, the orthophosphate product is released into solution; at pH 4 and pH 6, some remains adsorbed. The rate of hydrolysis is an order of magnitude more rapid than the same reaction facilitated by iron oxides. Because manganese dioxides are ubiquitous components of soils and sediments, this suggests the possibility of significant abiotic pathways for the formation of bioavailable orthophosphate from phosphate ester precursors.

  19. Using iron fertilizer to control Cd accumulation in rice plants: a new promising technology.

    PubMed

    Shao, GuoSheng; Chen, MingXue; Wang, DanYing; Xu, ChunMei; Mou, RenXiang; Cao, ZhaoYun; Zhang, XiuFu

    2008-03-01

    Effects of two kinds of iron fertilizer, FeSO4 and EDTA.Na2Fe were studied on cadmium accumulation in rice plants with two rice genotypes, Zhongzao 22 and Zhongjiazao 02, with soil culture systems. The results showed that application of iron fertilizers could hardly make adverse effects on plant growth and rice grain yield. Soil application of EDTA.Na2Fe significantly reduced the Cd accumulation in rice roots, shoots and rice grain. Cd concentration in white rice of both rice genotypes in the treatment of soil application of EDTA.Na2Fe was much lower than 0.2 mg/kg, the maximal Cd permission concentration in cereal crop foods in State standard. However, soil application of FeSO4 or foliar application of FeSO4 or EDTA.Na2Fe resulted in the significant increase of Cd accumulation in rice plants including rice grain compared with the control. The results also showed iron fertilizers increased the concentration of iron, copper and manganese element in rice grain and also affected zinc concentration in plants. It may be a new promising way to regulate Cd accumulation in rice grain in rice production through soil application of EDTA.Na2Fe fertilizers to maintain higher content of available iron and ferrous iron in soils.

  20. Hydrogen, acetate, and lactate as electron donors for microbial manganese reduction in a manganese-rich coastal marine sediment.

    PubMed

    Vandieken, Verona; Finke, Niko; Thamdrup, Bo

    2014-03-01

    The role of hydrogen, acetate, and lactate as electron donors for microbial manganese reduction was investigated in manganese-rich marine sediment from Gullmar Fjord (Sweden). Here, manganese reduction accounted for 50% of the anaerobic carbon oxidation at 0-15 cm sediment depth. In anoxic incubations from 0 to 5 cm depth, where manganese reduction dominated completely as terminal electron-accepting process, the combined contribution of acetate and lactate as electron donors for manganese reducers corresponded to < ¼ of the electron flow. The concentrations, ¹⁴C-radiotracer turnover rates, and contributions to carbon oxidation of acetate and lactate associated with manganese reduction were similar to those found in deeper horizons dominated by concomitant iron and sulfate reduction and sulfate reduction alone, respectively. By contrast, hydrogen concentrations increased considerably with sediment depth, indicating thermodynamic control of the competition between the electron-accepting processes, and hydrogen may have contributed substantially to the > 75% of the electron flow that did not involve acetate and lactate. Alternatively, the oxidation of more complex organic substrates could be involved. Our study provides the first direct evidence of substrate utilization by a natural manganese-reducing community and indicates similar mechanisms of thermodynamic control and competition for electron donors as known from sediments dominated by iron reduction, sulfate reduction, or methanogenesis.

  1. Iron, lanthanum and manganese oxides loaded on gamma-AI2O3 for selective catalytic reduction of NO with NH3 at low temperature.

    PubMed

    Zhao, Weiwei; Li, Caiting; Lu, Pei; Wen, Qingbo; Zhao, Yapei; Zhang, Xing; Fan, Chunzhen; Tao, Shasha

    2013-01-01

    A series of Mn/Al2O3, La-Mn/Al2O3 and Fe-La-Mn/Al2O3 catalysts were prepared by an impregnation method and investigated for selective catalytic reduction of NO with NH3 at low temperature. The experimental results revealed that NO conversion over La-Mn/Al2O3 was obviously improved after La doping. Addition of Fe increased both NO conversion and the resistance to H2O and SO2. The catalyst Fe0.04La0.03Mn0.06/Al2O3 with a load mass of MnO2 = 6%, La2O3 = 3% and Fe2O3 = 4% exhibited relatively high catalytic activity and yielded 98% NO conversion at 260 degrees with a space velocity of 15,000 h(-1). Meanwhile, the catalytic activity was slightly decreased in the presence of H2O and SO2. Moreover, the catalysts were characterized by N2 adsorption measurement, X-ray diffraction and X-ray photoelectron spectroscopy. The results showed that the doping of La enhanced the dispersion and oxidation states of Mn on the surface of Al2O3. On the surface of the Fe0.04La0.03Mn0.06/Al2O3 catalyst, La was highly dispersed and a mixed oxidation state of Mn existed, while iron ions were only in the Fe3+ state. The mechanism of selective catalytic reduction over these catalysts is also discussed. In this experiment, metal oxides loaded on the support were catalytic centres which served as electron transfer during NO reduction. The electron transfer between Mn3+ and Fe3+ might also exist and the mixture oxidation states of Mn on the surface of the Fe0.04La0.03Mn0.06/Al2O3 catalyst contributed to the SCR activity.

  2. Olfactory uptake of manganese requires DMT1 and is enhanced by anemia

    PubMed Central

    Thompson, Khristy; Molina, Ramon M.; Donaghey, Thomas; Schwob, James E.; Brain, Joseph D.; Wessling-Resnick, Marianne

    2008-01-01

    Manganese, an essential nutrient, can also elicit toxicity in the central nervous system (CNS). The route of exposure strongly influences the potential neurotoxicity of manganese-containing compounds. Recent studies suggest that inhaled manganese can enter the rat brain through the olfactory system, but little is known about the molecular factors involved. Divalent metal transporter-1 (DMT1) is the major transporter responsible for intestinal iron absorption and its expression is regulated by body iron status. To examine the potential role of this transporter in uptake of inhaled manganese, we studied the Belgrade rat, since these animals display significant defects in both iron and manganese metabolism due to a glycine-to-arginine substitution (G185R) in their DMT1 gene product. Absorption of intranasally instilled 54Mn was significantly reduced in Belgrade rats and was enhanced in iron-deficient rats compared to iron-sufficient controls. Immunohistochemical experiments revealed that DMT1 was localized to both the lumen microvilli and end feet of the sustentacular cells of the olfactory epithelium. Importantly, we found that DMT1 protein levels were increased in anemic rats. The apparent function of DMT1 in olfactory manganese absorption suggests that the neurotoxicity of the metal can be modified by iron status due to the iron-responsive regulation of the transporter. PMID:17116743

  3. Recovery of zinc and manganese, and other metals (Fe, Cu, Ni, Co, Cd, Cr, Na, K) from Zn-MnO2 and Zn-C waste batteries: Hydroxyl and carbonate co-precipitation from solution after reducing acidic leaching with use of oxalic acid

    NASA Astrophysics Data System (ADS)

    Sobianowska-Turek, A.; Szczepaniak, W.; Maciejewski, P.; Gawlik-Kobylińska, M.

    2016-09-01

    The article discusses the current situation of the spent batteries and portable accumulators management. It reviews recycling technologies of the spent batteries and portable accumulators which are used in the manufacturing installations in the world. Also, it presents the authors' research results on the reductive acidic leaching of waste material of the zinc-carbon batteries (Zn-C) and zinc-manganese batteries (alkaline Zn-MnO2) delivered by a company dealing with mechanical treatment of this type of waste stream. The research data proved that the reductive acidic leaching (H2SO4 + C2H2O4) of the battery's black mass allows to recover 85.0% of zinc and 100% of manganese. Moreover, it was found that after the reductive acidic leaching it is possible to recover nearly 100% of manganese, iron, cadmium, and chromium, 98.0% of cobalt, 95.5% of zinc, and 85.0% of copper and nickel from the solution with carbonate method. On the basis of the results, it is possible to assume that the carbonate method can be used for the preparation of manganese-zinc ferrite.

  4. Water resources in the vicinity of municipalities on the eastern Mesabi Iron Range and the Vermillion Iron Range, northeastern Minnesota

    USGS Publications Warehouse

    Cotter, R.D.; Young, H.L.; Petri, L.R.; Prior, C.H.

    1965-01-01

    Ground water commonly has a high concentration of iron and manganese and is hard. Surface water generally has a high concentration of iron and is colored. Analyses of water from many sources are included.

  5. Sources of cadmium in the environment.

    PubMed

    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.

  6. Cadmium inhalation and male reproductive toxicity

    SciTech Connect

    Ragan, H.A.; Mast, T.J. )

    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.

  7. Transcriptional regulation of metal transport genes and mineral nutrition during acclimatization to cadmium and zinc in the Cd/Zn hyperaccumulator, Thlaspi caerulescens (Ganges population).

    PubMed

    Küpper, Hendrik; Kochian, Leon V

    2010-01-01

    We investigated changes in mineral nutrient uptake and cellular expression levels for metal transporter genes in the cadmium (Cd)/zinc (Zn) hyperaccumulator, Thlaspi caerulescens during whole plant and leaf ontogenesis under different long-term treatments with Zn and Cd. Quantitative mRNA in situ hybridization (QISH) revealed that transporter gene expression changes not only dependent on metal nutrition/toxicity, but even more so during plant and leaf development. The main mRNA abundances found were: ZNT1, mature leaves of young plants; ZNT5, young leaves of young plants; MTP1 (= ZTP1 = ZAT), young leaves of both young and mature plants. Surprisingly different cellular expression patterns were found for ZNT1 and ZNT5, both belonging to the ZIP family of transition metal transporters: ZNT1, photosynthetic mesophyll and bundle sheath cells; ZNT5, nonphotosynthetic epidermal metal storage cells and bundle sheath cells. Thus, ZNT1 may function in micronutrient nutrition while ZNT5 may be involved in metal storage associated with hyperaccumulation. Cadmium inhibited the uptake of Zn, iron (Fe) and manganese (Mn), probably by competing for transporters or by interfering with the regulation of transporter gene expression. Cadmium-induced changes in cellular expression for ZNT1, ZNT5 and MTP1 could also be part of plant acclimatization to Cd toxicity. Defence against Cd toxicity involved enhanced uptake of magnesium (Mg), calcium (Ca) and sulphur (S).

  8. Globally sustainable manganese metal production and use.

    PubMed

    Hagelstein, Karen

    2009-09-01

    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 of dry-cell batteries, plant fertilizer components, animal feed and colorant for bricks. The manganese ore (high grade 35% manganese) production world wide is about 6 million ton/year and electrolytic manganese metal demand is about 0.7 million ton/year. The total manganese demand is consumed globally by industries including construction (23%), machinery (14%), and transportation (11%). Manganese is recycled within scrap of iron and steel, a small amount is recycled within aluminum used beverage cans. Recycling rate is 37% and efficiency is estimated as 53% [Roskill Metals and Minerals Reports, January 13, 2005. Manganese Report: rapid rise in output caused by Chinese crude steel production. Available from: http://www.roskill.com/reports/manganese.]. Environmentally sustainable management choices include identifying raw material chemistry, utilizing clean production processes, minimizing waste generation, recycling materials, controlling occupational exposures, and collecting representative environmental data. This paper will discuss two electrolytically produced manganese metals, the metal production differences, and environmental impacts cited to date. The two electrolytic manganese processes differ due to the addition of sulfur dioxide or selenium dioxide. Adverse environmental impacts due to use of selenium dioxide methodology include increased water consumption and order of magnitude greater solid waste generation per ton of metal processed. The use of high grade manganese ores in the electrolytic process also

  9. 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 < 0.01). The birds supplemented with Met-TM and Yeast-TM consumed less feed than the NC and ITM-supplemented group (p < 0.001). Supplementation of trace elements irrespective of source increased the total ash content in the tibia (p < 0.001). However, concentration of Cu was lower in the Met-TM and Yeast-TM groups compared with the NC and the ITM groups (p < 0.05) although that of Fe, Mn and Zn was not affected at all by the dietary treatments. Total protein concentration in serum increased when either Met-TM or Yeast-TM was supplemented (p < 0.05) to the birds. Serum alkaline phosphatase activity, however, increased when the trace elements from either inorganic or organic sources were supplemented (p < 0.05). Compared with the ITM-supplemented group, excretion of Cu, Fe, Mn and Zn was lower in the birds supplemented with Met-TM or Yeast-TM, especially in the latter group (p < 0.05). The present experiment revealed that supplementation of broilers with methionine chelates or yeast proteinate forms of Cu, Fe, Mn and Zn improved body weight and feed conversion ratio (FCR) and markedly reduced

  10. Effect of natural organic materials on cadmium and neptunium sorption

    SciTech Connect

    Kung, K.S.; Triay, I.R.

    1994-10-01

    In a batch sorption study of the effect of naturally occurring organic materials on the sorption of cadmium and neptunium on oxides and tuff surfaces, the model sorbents were synthetic goethite, boehmite, amorphous silicon oxides, and a crushed tuff material from Yucca Mountain, Nevada. An amino acid, 3-(3,4-dihydroxypheny)-DL-alanine (DOPA), and an aquatic-originated fulvic material, Nordic aquatic fulvic acid (NAFA), were used as model organic chemicals. Sorption isotherm results showed that DOPA sorption followed the order aluminum oxide > iron oxide > silicon oxide and that the amount of DOAP sorption for a given sorbent increased as the solution pH was raised. The sorption of cadmium and neptunium on the iron oxide was about ten times higher than that on the aluminum oxide. The sorption of cadmium and neptunium on natural tuff material was much lower than that on aluminum and iron oxides. The sorption of cadmium on iron and aluminum oxides was found to be influenced by the presence of DOPA, and increasing the amount of DOPA coating resulted in higher cadmium sorption on aluminum oxide. However, for iron oxide, cadmium sorption decreased with increasing DOPA concentration. The presence of the model organic materials DOPA and NAFA did not affect the sorption of neptunium on tuff material or on the iron and aluminum oxides. Spectroscopic results indicate that cadmium complexes strongly with DOPA. Therefore, the effect of the organic material, DOPA, on the cadmium sorption is readily observed. However, neptunium is possibly complexed weakly with organic material. Thus, DOPA and NAFA have little effect on neptunium sorption on all sorbents selected for study.

  11. Route and Regulation of Zinc, Cadmium, and Iron Transport in Rice Plants (Oryza sativa L.) during Vegetative Growth and Grain Filling: Metal Transporters, Metal Speciation, Grain Cd Reduction and Zn and Fe Biofortification.

    PubMed

    Yoneyama, Tadakatsu; Ishikawa, Satoru; Fujimaki, Shu

    2015-08-13

    Zinc (Zn) and iron (Fe) are essential but are sometimes deficient in humans, while cadmium (Cd) is toxic if it accumulates in the liver and kidneys at high levels. All three are contained in the grains of rice, a staple cereal. Zn and Fe concentrations in rice grains harvested under different levels of soil/hydroponic metals are known to change only within a small range, while Cd concentrations show greater changes. To clarify the mechanisms underlying such different metal contents, we synthesized information on the routes of metal transport and accumulation in rice plants by examining metal speciation, metal transporters, and the xylem-to-phloem transport system. At grain-filling, Zn and Cd ascending in xylem sap are transferred to the phloem by the xylem-to-phloem transport system operating at stem nodes. Grain Fe is largely derived from the leaves by remobilization. Zn and Fe concentrations in phloem-sap and grains are regulated within a small range, while Cd concentrations vary depending on xylem supply. Transgenic techniques to increase concentrations of the metal chelators (nicotianamine, 2'-deoxymugineic acid) are useful in increasing grain Zn and Fe concentrations. The elimination of OsNRAMP5 Cd-uptake transporter and the enhancement of root cell vacuolar Cd sequestration reduce uptake and root-to-shoot transport, respectively, resulting in a reduction of grain Cd accumulation.

  12. Seasonal variability in cadmium, lead, copper, zinc and iron concentrations in the three major fish species, Oreochromis niloticus, Lates niloticus and Rastrineobola argentea in Winam Gulf, Lake Victoria: impact of wash-off into the lake.

    PubMed

    Ongeri, David M K; Lalah, Joseph O; Wandiga, Shem O; Schramm, Karl-Werner; Michalke, Bernard

    2012-02-01

    Trace metals Cadmium (Cd), Lead (Pb), Copper (Cu), Zinc (Zn) and Iron (Fe) were analyzed in edible portions of three main finfish species namely Lates niloticus, Oreochromis niloticus and Rastrineobola argentea sampled from various beaches of Winam Gulf, Lake Victoria, Kenya, in order to determine any seasonal and site variations and the results showed significantly (p < 0.05) higher mean concentrations of Cd, Cu, Zn and Fe during the wet season compared to the dry season for all the three species indicating the impact of wash-off into the lake during the rainy periods. The overall mean concentrations of the heavy metals (in μg/g dry weight) in all combined samples ranged from 0.17-0.40 (Cd), 0.47-2.53 (Pb), 2.13-8.74 (Cu), 28.9-409.3 (Zn) and 31.4-208.1 (Fe), respectively. It was found that consumption of Rastrineobola argentea can be a significant source of heavy metals especially Zn, to humans, compared with Lates niloticus and Oreochromis niloticus, if only the muscle parts of the latter two are consumed.

  13. Activity of the AtMRP3 promoter in transgenic Arabidopsis thaliana and Nicotiana tabacum plants is increased by cadmium, nickel, arsenic, cobalt and lead but not by zinc and iron.

    PubMed

    Zientara, Katarzyna; Wawrzyńska, Anna; Lukomska, Jolanta; López-Moya, José Rafael; Liszewska, Frantz; Assunção, Ana G L; Aarts, Mark G M; Sirko, Agnieszka

    2009-02-05

    Characterization of the function, regulation and metal-specificity of metal transporters is one of the basic steps needed for the understanding of transport and accumulation of toxic metals and metalloids by plants. In this work GUS was used as a reporter for monitoring the activity of the promoter of the AtMRP3 gene from Arabidopsis thaliana, a gene encoding an ABC-transporter, expression of which is induced by heavy metals. The AtMRP3 promoter-GUS fusion expression cassette was introduced into the genome of two model plants, A. thaliana and Nicotiana tabacum. The promoter induces GUS activity in the roots as well as in the shoots upon metal exposure. Similar responses of the AtMRP3 promoter to the presence of the selected metals was observed in both plant species. Cadmium, nickel, arsenic, cobalt and lead strongly activated the transcription of the reporter gene, while zinc and iron had no impact. The AtMRP3 promoter thus seems to be a useful new tool in designing plants that can be used for biomonitoring of environmental contaminations.

  14. Route and Regulation of Zinc, Cadmium, and Iron Transport in Rice Plants (Oryza sativa L.) during Vegetative Growth and Grain Filling: Metal Transporters, Metal Speciation, Grain Cd Reduction and Zn and Fe Biofortification

    PubMed Central

    Yoneyama, Tadakatsu; Ishikawa, Satoru; Fujimaki, Shu

    2015-01-01

    Zinc (Zn) and iron (Fe) are essential but are sometimes deficient in humans, while cadmium (Cd) is toxic if it accumulates in the liver and kidneys at high levels. All three are contained in the grains of rice, a staple cereal. Zn and Fe concentrations in rice grains harvested under different levels of soil/hydroponic metals are known to change only within a small range, while Cd concentrations show greater changes. To clarify the mechanisms underlying such different metal contents, we synthesized information on the routes of metal transport and accumulation in rice plants by examining metal speciation, metal transporters, and the xylem-to-phloem transport system. At grain-filling, Zn and Cd ascending in xylem sap are transferred to the phloem by the xylem-to-phloem transport system operating at stem nodes. Grain Fe is largely derived from the leaves by remobilization. Zn and Fe concentrations in phloem-sap and grains are regulated within a small range, while Cd concentrations vary depending on xylem supply. Transgenic techniques to increase concentrations of the metal chelators (nicotianamine, 2′-deoxymugineic acid) are useful in increasing grain Zn and Fe concentrations. The elimination of OsNRAMP5 Cd-uptake transporter and the enhancement of root cell vacuolar Cd sequestration reduce uptake and root-to-shoot transport, respectively, resulting in a reduction of grain Cd accumulation. PMID:26287170

  15. Air Manganese Study

    EPA Pesticide Factsheets

    In November 2011 US EPA researchers conducted a health study of airborne manganese exposure in East Liverpool, Ohio. This Web site discusses preliminary results of the study and provides background and other related information.

  16. Manganese deposition in drinking water distribution systems.

    PubMed

    Gerke, Tammie L; Little, Brenda J; Barry Maynard, J

    2016-01-15

    This study provides a physicochemical assessment of manganese deposits on brass and lead components from two fully operational drinking water distributions systems. One of the systems was maintained with chlorine; the other, with secondary chloramine disinfection. Synchrotron-based in-situ micro X-ray adsorption near edge structure was used to assess the mineralogy. In-situ micro X-ray fluorescence mapping was used to demonstrate the spatial relationships between manganese and potentially toxic adsorbed metal ions. The Mn deposits ranged in thickness from 0.01 to 400 μm. They were composed primarily of Mn oxides/oxhydroxides, birnessite (Mn(3+) and Mn(4+)) and hollandite (Mn(2+) and Mn(4+)), and a Mn silicate, braunite (Mn(2+) and Mn(4+)), in varying proportions. Iron, chromium, and strontium, in addition to the alloying elements lead and copper, were co-located within manganese deposits. With the exception of iron, all are related to specific health issues and are of concern to the U.S. Environmental Protection Agency (U.S. EPA). The specific properties of Mn deposits, i.e., adsorption of metals ions, oxidation of metal ions and resuspension are discussed with respect to their influence on drinking water quality.

  17. Redox dynamics of manganese as a mitochondrial life-death switch

    PubMed Central

    Smith, Matthew Ryan; Fernandes, Jolyn; Go, Young-Mi; Jones, Dean P.

    2017-01-01

    Sten Orrenius, M.D., Ph.D., pioneered many areas of cellular and molecular toxicology and made seminal contributions to our knowledge of oxidative stress and glutathione (GSH) metabolism, organellar functions and Ca+2-dependent mechanisms of cell death, and mechanisms of apoptosis. On the occasion of his 80th birthday, we summarize current knowledge on redox biology of manganese (Mn) and its role in mechanisms of cell death. Mn is found in all organisms and has critical roles in cell survival and death mechanisms by regulating Mn-containing enzymes such as manganese superoxide dismutase (SOD2) or affecting expression and activity of caspases. Occupational exposures to Mn cause “manganism”, a Parkinson's disease-like condition of neurotoxicity, and experimental studies show that Mn exposure leads to accumulation of Mn in the brain, especially in mitochondria, and neuronal cell death occurs with features of an apoptotic mechanism. Interesting questions are why a ubiquitous metal that is essential for mitochondrial function would accumulate to excessive levels, cause increased H2O2 production and lead to cell death. Is this due to the interactions of Mn with other essential metals, such as iron, or with toxic metals, such as cadmium? Why is the Mn loading in the human brain so variable, and why is there such a narrow window between dietary adequacy and toxicity? Are non-neuronal tissues similarly vulnerable to insufficiency and excess, yet not characterized? We conclude that Mn is an important component of the redox interface between an organism and its environment and warrants detailed studies to understand the role of Mn as a mitochondrial life-death switch. PMID:28212723

  18. High manganese concentrations in rocks at Gale crater, Mars

    USGS Publications Warehouse

    Lanza, Nina L.; Fischer, Woodward W.; Wiens, Roger C.; Grotzinger, John; Ollila, Ann M.; Anderson, Ryan B.; Clark, Benton C.; Gellert, Ralf; Mangold, Nicolas; Maurice, Sylvestre; Le Mouélic, Stéphane; Nachon, Marion; Schmidt, Mariek E.; Berger, Jeffrey; Clegg, Samuel M.; Forni, Olivier; Hardgrove, Craig; Melikechi, Noureddine; Newsom, Horton E.; Sautter, Violaine

    2014-01-01

    The surface of Mars has long been considered a relatively oxidizing environment, an idea supported by the abundance of ferric iron phases observed there. However, compared to iron, manganese is sensitive only to high redox potential oxidants, and when concentrated in rocks, it provides a more specific redox indicator of aqueous environments. Observations from the ChemCam instrument on the Curiosity rover indicate abundances of manganese in and on some rock targets that are 1–2 orders of magnitude higher than previously observed on Mars, suggesting the presence of an as-yet unidentified manganese-rich phase. These results show that the Martian surface has at some point in time hosted much more highly oxidizing conditions than has previously been recognized.

  19. Ion-Selective Deposition of Manganese Sulphate Solution from Trenggalek Manganese Ore by Active Carbon and Sodium Hydroxide

    NASA Astrophysics Data System (ADS)

    Andriyah, L.; Sulistiyono, E.

    2017-02-01

    One of the step in manganese dioxide manufacturing process for battery industry is a purification process of lithium manganese sulphate solution. The elimination of impurities such as iron removal is important in hydrometallurgical processes. Therefore, this paper present the purification results of manganese sulphate solution by removing impurities using a selective deposition method, namely activated carbon adsorption and NaOH. The experimental results showed that the optimum condition of adsorption process occurs on the addition of 5 g adsorbent and the addition of 10 ml NaOH 1 N, processing time of 30 minutes and the best is the activated carbon adsorption of Japan. Because the absolute requirement of the cathode material of lithium ion manganese are free of titanium then of local wood charcoal is good enough in terms of eliminating ions Ti is equal to 70.88%.

  20. Lipid peroxidation in the gill and hepatopancreas of Oziotelphusa senex senex fabricius during cadmium and copper exposure

    SciTech Connect

    Reddy, P.S. ); Bhagyalakshmi, A. )

    1994-11-01

    Environmental contamination by metals has increased in recent years due to the excessive use of metals in agriculture and industry. Due to their bioconcentration, immutable and non-degradable properties, these metals constitute a major source of pollutants. Among these metals cadmium, lead and mercury are non-essential, where as copper, iron, manganese, and zinc are essential elements. They are required in trace amounts by all forms of life but are toxic when present in excess. Considerable information is available on the toxic effects of cadmium on biological mechanisms at all integration levels, such as molecular, biochemical, physiological and behavioural, in animals. It is also well known that heavy metal contamination alters cellular physiology, particularly by affecting aspects such as transport across plasma membranes, mitochondrial functions, lysosomal stability etc. Even though it has been demonstrated that the in vitro addition of heavy metals stimulates membrane lipid peroxidation, the in vivo effects exerted by different cations on this process are still not clear. The present work reports the effect of exposure to sublethal concentrations of heavy metals such as Cu and Cd on lipid peroxidation in the tissues of the edible freshwater crab, Oziotelphusa senex senex. 16 refs., 3 tabs.

  1. Oscillator strengths for ionized iron and manganese

    NASA Technical Reports Server (NTRS)

    De Boer, K. S.; Pottasch, S. R.; Morton, D. C.; York, D. G.

    1974-01-01

    The observed strengths of interstellar absorption lines of Fe II and Mn II in the spectra of alpha Vir, beta Cen, pi Sco, and zeta Oph along with laboratory f values of some of these lines between 2343 and 2606 A have been used to determine curves of growth for these ions and the f-values of ten lines of Fe II and three lines of Mn II between 1055 and 1261 A. The Fe and Mn abundances are derived.

  2. 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.

  3. Cadmium and the kidney.

    PubMed Central

    Friberg, L

    1984-01-01

    The paper is a review of certain aspects of importance of cadmium and the kidney regarding the assessment of risks and understanding of mechanisms of action. The review discusses the following topics: history and etiology of cadmium-induced kidney dysfunction and related disorders; cadmium metabolism, metallothionein and kidney dysfunction; cadmium in urine as indicator of body burden, exposure and kidney dysfunction; cadmium levels in kidney and liver as indicators of kidney dysfunction; characteristics of early kidney dysfunction; the critical concentration concept; critical concentrations of cadmium in kidney cortex; and prognosis. PMID:6734547

  4. The effects of point pollutants-originated heavy metals (lead, copper, iron, and cadmium) on fish living in Yeşilırmak River, Turkey.

    PubMed

    Polat, Fatih; Akın, Şenol; Yıldırım, Alper; Dal, Tarık

    2016-08-01

    In this study, the association between heavy metals in water and cyprinids sampled from the Yeşilırmak River stretch, which is frequently exposed to pollutant sources (a sugar production factory (Turhal) and solid wastes dump area (Taşlıçiftlik) was explored, and the oxidative effects of heavy metals on cyprinids were evaluated through analyzing some liver enzymes, namely, superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and cortisol. The heavy metal concentrations of both fish and water, collected from three different locations along the river during the summer of 2011 and winter of 2010 (Turhal, Taşlıçiftlik, and Gümenek), were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The water and fish liver heavy metal concentrations exhibited increasing trends from upstream (Gümenek) to downstream (Turhal). The water and liver samples collected during the summer had higher heavy metal concentrations than those obtained during the winter. The mean heavy metal concentrations increased from Gümenek to Turhal. The liver heavy metal concentrations were higher than those in the water and exhibited almost the same increasing trend from Gümenek to Turhal. Positive relationships between liver and water heavy metal concentrations, especially for cadmium (R (2) = 0.91) and lead (R (2) = 0.98), were obtained. Among the liver enzymes, only MDA followed the same increasing trend from Gümenek to Turhal as was obtained for heavy metals. On the other hand, CAT and SOD had a contrary spatial pattern of change to those of heavy metals and MDA. Although the values of heavy metals and MDA in Taşlıçiftlik were between the two other locations, fish inhabiting this locality had significantly higher values of cortisol, which is an indication of the other stress-causing factors for fish.

  5. Occupational exposure to manganese.

    PubMed Central

    Sarić, M; Markićević, A; Hrustić, O

    1977-01-01

    The relationship between the degree of exposure and biological effects of manganese was studied in a group of 369 workers employed in the production of ferroalloys. Two other groups of workers, from an electrode plant and from an aluminium rolling mill, served as controls. Mean manganese concentrations at work places where ferroalloys were produced varied from 0-301 to 20-442 mg/m3. The exposure level of the two control groups was from 2 to 30 microgram/m3 and from 0-05 to 0-07 microgram/m3, in the electrode plant and rolling mill respectively. Sixty-two (16-8%) manganese alloy workers showed some signs of neurological impairment. These signs were noticeably less in the two control groups (5-8% and 0%) than in the occupationally exposed group. Subjective symptoms, which are nonspecific but may be symptoms of subclinical manganism, were not markedly different in the three groups. However, in the manganese alloy workers some of the subjective symptoms occurred more frequently in heavier smokers than in light smokers or nonsmokers. Heavier smokers engaged in manganese alloy production showed some of the subjective symptoms more often than heavier smokers from the control groups. PMID:871441

  6. Manganese As a Metal Accumulator

    EPA Science Inventory

    Manganese deposits in water distribution systems accumulate metals, radionuclides and oxyanions by a combination of surface complexation, adsorption and solid substitution, as well as a combination of oxidation followed by manganese reduction and sorption of the oxidized constitu...

  7. Cadmium and zinc relationships.

    PubMed

    Elinder, C G; Piscator, M

    1978-08-01

    Cadmium and zinc concentrations in kidney and liver have been measured under different exposure situations in different species including man. The results show that zinc increases almost equimolarly with cadmium in kidney after long-term low-level exposure to cadmium, e.g., in man, horse, pig, and lamb. In contrast, the increase of zinc follows that of cadmium to only a limited extent, e.g., in guinea pig, rabbit, rat, mouse, and chicks. In liver, the cadmium--zinc relationship seems to be reversed in such a way that zinc increases with cadmium more markedly in laboratory animals than in higher mammals. These differences between cadmium and zinc relationships in humans and large farm animals and those in commonly used laboratory animals must be considered carefully before experimental data on cadmium and zinc relationships in laboratory animals can be extrapolated to humans.

  8. Copper, iron and the organic ligands that bind them - updates from San Francisco Bay and beyond

    NASA Astrophysics Data System (ADS)

    Buck, K. N.; Bundy, R.; Biller, D.; Bruland, K. W.; Barbeau, K.

    2015-12-01

    Building on more than 30 years of measurements in San Francisco Bay by Russ Flegal and others, the concentrations of dissolved manganese, iron, cobalt, nickel, copper, zinc, cadmium and lead were determined from a suite of water quality monitoring program stations in North, Central and South Bay using inductively coupled plasma- mass spectrometry following preconcentration on a Nobias-chelate PA1 resin. Given the importance of organic ligands in governing iron solubility and copper bioavailability in natural waters, the organic complexation of dissolved iron and copper in these samples was determined from multiple analytical windows applied to competitive ligand exchange- adsorptive cathodic stripping voltammetry. This study constitutes the first dataset of iron speciation in San Francisco Bay and expands upon prior work evaluating the potential for copper toxicity in this urbanized estuary. Recent advances in voltammetric techniques emerging from a Scientific Committee on Oceanic Research (SCOR) working group on metal-binding ligands in the marine environment, and insights gained from high-resolution ligand measurements from the U.S. GEOTRACES program, highlight how metal-binding ligands in San Francisco Bay compare with those of the coastal and open ocean.

  9. Manganese biomining: A review.

    PubMed

    Das, A P; Sukla, L B; Pradhan, N; Nayak, S

    2011-08-01

    Biomining comprises of processing and extraction of metal from their ores and concentrates using microbial techniques. Currently this is used by the mining industry to extract copper, uranium and gold from low grade ores but not for low grade manganese ore in industrial scale. The study of microbial genomes, metabolites and regulatory pathways provide novel insights to the metabolism of bioleaching microorganisms and their synergistic action during bioleaching operations. This will promote understanding of the universal regulatory responses that the biomining microbial community uses to adapt to their changing environment leading to high metal recovery. Possibility exists of findings ways to imitate the entire process during industrial manganese biomining endeavor. This paper reviews the current status of manganese biomining research operations around the world, identifies factors that drive the selection of biomining as a processing technology, describes challenges in exploiting these innovations, and concludes with a discussion of Mn biomining's future.

  10. 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.

  11. Cadmium sulfide membranes

    DOEpatents

    Spanhel, Lubomir; Anderson, Marc A.

    1991-10-22

    A method is described for the creation of novel q-effect cadmium sulfide membranes. The membranes are made by first creating a dilute cadmium sulfide colloid in aqueous suspension and then removing the water and excess salts therefrom. The cadmium sulfide membrane thus produced is luminescent at room temperature and may have application in laser fabrication.

  12. Cadmium sulfide membranes

    DOEpatents

    Spanhel, Lubomir; Anderson, Marc A.

    1992-07-07

    A method is described for the creation of novel q-effect cadmium sulfide membranes. The membranes are made by first creating a dilute cadmium sulfide colloid in aqueous suspension and then removing the water and excess salts therefrom. The cadmium sulfide membrane thus produced is luminescent at room temperature and may have application in laser fabrication.

  13. Determination of the oxidizing capacity of manganese ores.

    PubMed

    Prasad, R

    1974-09-01

    An accurate method is described for determining the amount of active oxygen in manganese ores, based on the oxidation-reduction reaction between the ore and arsenic(III) in presence of ammonium molybdate, followed by the back-titration of excess of arsenic(III) with cerium(IV), using osmium tetroxide as catalyst and Disulphine Blue V as indicator. A survey has been made of the applicability of this method to various pyrolusite ores containing less than 0.2% phosphorus. Aluminium(III), copper(II), iron(III), manganese(II), and molybdenum(VI) do not interfere. Up to 30% phosphorus(V) causes no interference.

  14. Lanthanum Cerium Manganese Hexaaluminate Combustion Catalysts for Compact Steam Reformers

    DTIC Science & Technology

    2005-12-07

    monoxide, and ethylene as partial oxidation products. Of the metals tested, iron is best, followed by cobalt and cerium. Our results concur with Wang et...that of Groppi et al., which marginally outperformed LaMnAl11O19 [15]. Our bimetallic manganese- cobalt catalyst was similarly lacking and did not...LaCo0.5Mn0.5Al11O19 are nearly identical and that in the absence of manganese, cobalt - and cerium-substituted hexaaluminates are equivalent catalysts. It

  15. Soluble Moringa oleifera leaf extract reduces intracellular cadmium accumulation and oxidative stress in Saccharomyces cerevisiae.

    PubMed

    Kerdsomboon, Kittikhun; Tatip, Supinda; Kosasih, Sattawat; Auesukaree, Choowong

    2016-05-01

    Moringa oleifera leaves are a well-known source of antioxidants and traditionally used for medicinal applications. In the present study, the protective action of soluble M. oleifera leaf extract (MOLE) against cadmium toxicity was investigated in the model eukaryote Saccharomyces cerevisiae. The results showed that this extract exhibited a protective effect against oxidative stress induced by cadmium and H2O2 through the reduction of intracellular reactive oxygen species. Interestingly, not only the co-exposure of soluble MOLE with cadmium but also pretreatment of this extract prior to cadmium exposure significantly reduced the cadmium uptake through an inhibition of Fet4p, a low-affinity iron(II) transporter. In addition, the supplementation of soluble MOLE significantly reduced intracellular iron accumulation in a Fet4p-independent manner. Our findings suggest the potential use of soluble extract from M. oleifera leaves as a dietary supplement for protection against cadmium accumulation and oxidative stress.

  16. 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 α-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

  17. Manganese, Metallogenium, and Martian Microfossils

    NASA Technical Reports Server (NTRS)

    Stein, L. Y.; Nealson, K. H.

    1999-01-01

    Manganese could easily be considered an abundant element in the Martian regolith, assuming that the composition of martian meteorites reflects the composition of the planet. Mineralogical analyses of 5 SNC meteorites have revealed an average manganese oxide concentration of 0.48%, relative to the 0.1% concentration of manganese found in the Earth's crust. On the Earth, the accumulation of manganese oxides in oceans, soils, rocks, sedimentary ores, fresh water systems, and hydrothermal vents can be largely attributed to microbial activity. Manganese is also a required trace nutrient for most life forms and participates in many critical enzymatic reactions such as photosynthesis. The wide-spread process of bacterial manganese cycling on Earth suggests that manganese is an important element to both geology and biology. Furthermore, there is evidence that bacteria can be fossilized within manganese ores, implying that manganese beds may be good repositories for preserved biomarkers. A particular genus of bacteria, known historically as Metallogenium, can form star-shaped manganese oxide minerals (called metallogenium) through the action of manganese oxide precipitation along its surface. Fossilized structures that resemble metallogenium have been found in Precambrian sedimentary formations and in Cretaceous-Paleogene cherts. The Cretaceous-Paleogene formations are highly enriched in manganese and have concentrations of trace elements (Fe, Zn, Cu, and Co) similar to modern-day manganese oxide deposits in marine environments. The appearance of metallogenium-like fossils associated with manganese deposits suggests that bacteria may be preserved within the minerals that they form. Additional information is contained in the original extended abstract.

  18. Cadmium and renal cancer

    SciTech Connect

    Il'yasova, Dora; Schwartz, Gary G. . 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. 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...

  20. 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.

  1. 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.

  2. Terrestrial manganese-53 — A new monitor of Earth surface processes

    NASA Astrophysics Data System (ADS)

    Schaefer, Joerg M.; Faestermann, Thomas; Herzog, Gregory F.; Knie, Klaus; Korschinek, Gunther; Masarik, Jozef; Meier, Astrid; Poutivtsev, Michail; Rugel, Georg; Schlüchter, Christian; Serifiddin, Feride; Winckler, Gisela

    2006-11-01

    We report the first systematic study of the terrestrial cosmogenic radionuclide manganese-53 ( T1/2 = 3.7 Ma) measured in thirteen samples from nine dolerite surfaces in the Dry Valleys, Antarctica. The terrestrial manganese-53 concentrations correlate well with cosmic-ray-produced helium-3 and neon-21 concentrations in the same samples, implying that the manganese-53 is produced continuously in situ and retained quantitatively over millions of years. The terrestrial manganese-53 production rate determination normalized to iron (the only important target element) and to high-latitude and sealevel yields a value of P53 = 103 ± 11 atoms yr - 1 (g Fe) - 1 . This is consistent with the theoretical value of 120 ± 18 atoms yr - 1 (g Fe) - 1 obtained from modeling calculations. Our results show that the manganese-53 concentrations in bulk terrestrial rocks can be used to monitor Earth surface processes on time-scales exceeding 10 My.

  3. Prediction of cadmium concentration in selected home-produced vegetables.

    PubMed

    Bešter, Petra Karo; Lobnik, Franc; Eržen, Ivan; Kastelec, Damijana; Zupan, Marko

    2013-10-01

    Soil contaminated with cadmium presents a potential hazard for humans, animals and plants. The latter play a major role in the transfer of cadmium to the food chain. The uptake of cadmium and its accumulation by plants is dependent on various soil, plants and environmental factors. In order to identify soil properties with statistically significant influence on cadmium concentration in vegetables and to reduce the collection of data, time and costs, regression models can be applied. The main objective of this research was to develop regression models to predict the concentration of cadmium in 9-vegetable species: zucchini, tomato, cabbage, onion, potato, carrot, red beet, endive and chicory, based on soil properties. Soil samples were collected from 123 home gardens of the Municipality of Celje and 59 of these gardens were also included in vegetable sampling. The concentration of elements (e.g. arsenic, cadmium, copper, lead, and zinc) in the samples was determined by Inductively Coupled Plasma Mass Spectrometry. Single (for cabbage, potato, red beet and chicory) and multiple (for tomato, onion, carrot and endive) linear regression models were developed. There was no statistically significant regression model for zucchini. The most significant parameter for the influencing the cadmium concentration in vegetables was the concentration of cadmium in soil. Other important soil properties were the content of organic matter, pH-value and the concentration of manganese. It was concluded that consuming carrots, red beets, endives, onions, potatoes and chicory which are grown in gardens with Cd concentrations (mgkg(-1) DW) above 2.4, 3.2, 6.3, 7.9, 8.3 and 10.9, respectively, might represent an important contribution to dietary Cd exposure.

  4. Effect of coated urea on cadmium accumulation in Oryza sativa L. grown in contaminated soil.

    PubMed

    Xu, Chao; Wu, Zisong; Zhu, Qihong; Zhu, Hanhua; Zhang, Yangzhu; Huang, Daoyou

    2015-11-01

    Experiments were conducted to determine the effects of three types of coated urea on the accumulation of cadmium (Cd) in rice (Oryza sativa L.) grown in contaminated soil. Pot-culture experiments were conducted in a greenhouse from July to November 2012 on the rice cultivar "Hua Hang Si Miao" in Guangzhou (China). The experimental design was completely randomized with four treatments and three replications. The treatments were control (CK) (N 0 mg/kg), prilled urea (PU) (N 200 mg/kg), polymer-coated urea (PCU) (N 200 mg/kg), and sulfur-coated urea (SCU) (N 200 mg/kg). Our results indicated that applications of PCU and SCU slightly increased the dry weight of rice grains. The application of SCU significantly decreased the CaCl2 and toxicity characteristic leaching procedure (TCLP)-extractable Cd concentrations by 15.4 and 56.1%, respectively. Sequential extractions showed that PCU and SCU applications led to a significant decrease in Cd in the exchangeable fraction and an increase in the bound iron (Fe) and manganese (Mn) oxides fractions. Cd concentrations in grains treated with PCU were reduced by 11.7%, whereas SCU significantly reduced Cd concentrations by 29.1%. SCU reduced Cd transfer from the straws to the grain. Our results demonstrated that PCU and SCU may be effective in mitigating Cd accumulation in rice grown in acidic Cd-contaminated soil, especially in plants receiving SCU.

  5. The possible role of gradual accumulation of copper, cadmium, lead and iron and gradual depletion of zinc, magnesium, selenium, vitamins B2, B6, D, and E and essential fatty acids in multiple sclerosis.

    PubMed

    Johnson, S

    2000-09-01

    Multiple sclerosis (MS) has a much higher incidence among caucasians that in any other race. Furthermore: females are much more susceptible than males and white females living in colder, wetter areas are much more susceptible than those living in warmer areas. On the other hand, menstruating women have increased copper (Cu) absorption and half-life, so they tend to accumulate more Cu than males. Moreover, rapidly growing girls have an increased demand for zinc (Zn), but their rapidly decreasing production of melatonin results in impaired Zn absorption, which is exacerbated by the high Cu levels. The low Zn levels result in deficient CuZnSuperoxide dismutase (CuZnSOD), which in turn leads to increased levels of superoxide. Menstruating females also often present with low magnesium (Mg) and vitamin B6 levels. Vitamin B6 moderates intracellular nitric oxide (NO) production and extracellular Mg is required for NO release from the cell, so that a deficiency of these nutrients results in increased NO production in the cell and reduced release from the cell. The trapped NO combines with superoxide to form peroxinitrite, an extremely powerful free radical that leads to the myelin damage of MS. Iron (Fe), molybdenum (Mo) and cadmium (Cd) accumulation also increase superoxide production. Which explains MS in males, who tend to accumulate Fe much faster and Cu much less rapidly than females. Since vitamin D is paramount for Mg absorption, the much reduced exposure to sunlight in the higher latitudes may account for the higher incidence in these areas. Moreover, vitamin B2 is a cofactor for xanthine oxidase, and its deficiency exacerbates the low levels of uric acid caused by high Cu levels, resulting in myelin degeneration. Finally Selenium (Se) and vitamin E prevent lipid peroxidation and EPA and DHA upregulate CuZnSOD. Therefore, supplementation with 100 mg MG, 25 mg vit B6, 10 mg vit B2, 15 mg Zn and 400 IU vit D and E, 100 microg Se, 180 mg EPA and 120 mg DHA per day

  6. Manganese in Madison's drinking water.

    PubMed

    Schlenker, Thomas; Hausbeck, John; Sorsa, Kirsti

    2008-12-01

    Public concern over events of manganese-discolored drinking water and the potential for adverse health effects from exposure to excess manganese reached a high level in 2005. In response, Public Health Madison Dane County, together with the Madison Water Utility, conceived and implemented a public health/water utility strategy to quantify the extent of the manganese problem, determine the potential for adverse human health effects, and communicate these findings to the community. This strategy included five basic parts: taking an inventory of wells and their manganese levels, correlating manganese concentration with turbidity, determining the prevalence and distribution of excess manganese in Madison households, reviewing the available scientific literature, and effectively communicating our findings to the community. The year-long public health/water utility strategy successfully resolved the crisis of confidence in the safety of Madison's drinking water.

  7. Cadmium in tobacco

    SciTech Connect

    Yue, L. )

    1992-03-01

    The present study was conducted to determine the cadmium level in tobacco planted in five main tobacco-producing areas, a cadmium polluted area, and in cigarettes produced domestically (54 brands). The results indicate that average cadmium content in tobacco was 1.48 (0.10-4.95 mg/kg), which was similar to that of Indian tobacco (1.24 mg/kg), but the cadmium of tobacco produced in the cadmium polluted area was quite high (8.60 mg/kg). The average cigarette cadmium was 1.05 micrograms/g (with filter tip) and 1.61 micrograms/g (regular cigarette). Therefore special attention should be paid to the soil used in planting tobacco.

  8. 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

  9. Cadmium - A metallohormone?

    SciTech Connect

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

    2009-08-01

    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.

  10. 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.

  11. Cadmium exposure and nephropathy in a 28-year-old female metals worker.

    PubMed Central

    Wittman, Richard; Hu, Howard

    2002-01-01

    -mandated monitoring and screening measures, it is prudent for those with cadmium exposure to maintain adequate intake of both iron and calcium, appropriate measures even in the absence of exposure. PMID:12460807

  12. Effects of dietary manganese and iron on manganese and iron metabolism during infancy

    SciTech Connect

    Kiehl, H.; Loennerdal, B. )

    1991-03-15

    To derive a better understanding of the metabolism of Mn during infancy, infant formulas with different levels of Mn and Fe were labeled with {sup 54}Mn and {sup 59}Fe and administered orally to suckling rats: control low-Fe formula; control with 100-times Mn; and control with 100-times Fe. Another group received 200 {mu}g MnCl{sub 2} daily during infancy. 12 hr post-dosing, the pattern of {sup 54}Mn distribution in the tissues paralleled that of {sup 59}Fe. An excess of either mineral decreased overall retention but led to higher recoveries of both elements in the proximal intestine and liver. Conversely, these recoveries in pups given Mn from birth were lower than in controls. Analysis of the cytosolic fractions from intestine and liver using FPLC gel filtration demonstrated the impact of the mineral loads on protein profiles. In all cases except the high-Mn dose, dietary manipulations resulted in greater relative levels of a high molecular weight protein with MW similar to ferritin. The high-Mn formula seemed to induce in the hepatocyte a lower MW protein with which most of the {sup 54}Mn and {sup 59}Fe was associated. These results suggest a possible role of Mn as a regulator in the synthesis of cytosolic proteins of the enterocyte and hepatocyte in infants.

  13. Manganese accumulation in striatum of mice exposed to toxic doses is dependent upon a functional dopamine transporter.

    PubMed

    Erikson, Keith M; John, Carrie E; Jones, Sara R; Aschner, Michael

    2005-11-01

    The objective of this study was to determine the importance of the dopamine transporter (DAT) in manganese transport. Excessive manganese exposure is associated with a neurotoxicological disease known as manganism characterized by a specific accumulation of manganese in dopamine-rich brain regions. It has been hypothesized that the DAT mediates this specific transport, but its role in manganese neurotoxicity has not been directly examined. We examined brain tissues from manganese-exposed dopamine transporter knockout (DAT-KO) and wild-type (WT) mice. There was significantly less (p<0.05) manganese in the striatum of exposed DAT-KO mice compared to WT. However, the absence of a functioning DAT did not affect manganese accumulation in other brain regions examined. Furthermore, both iron and divalent metal transporter levels (two known modulators of brain manganese) were similar between DAT-KO and WT mice in all brain regions. These studies demonstrate that the DAT is involved in the facilitation of striatal manganese accumulation and that it may play a critical role in mediating manganese neurotoxicity.

  14. 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

  15. Manganese accumulates within golgi apparatus in dopaminergic cells as revealed by synchrotron X-ray fluorescence nanoimaging.

    PubMed

    Carmona, Asunción; Devès, Guillaume; Roudeau, Stéphane; Cloetens, Peter; Bohic, Sylvain; Ortega, Richard

    2010-03-17

    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.

  16. Mn(II) removal from groundwater with manganese oxide-coated filter media.

    PubMed

    Piispanen, Jutta K; Sallanko, Jarmo T

    2010-11-01

    Removing soluble manganese from groundwater requires a strong chemical oxidant, such as ozone or potassium permanganate, or raising the pH to alkaline value (over pH 9). Biological or adsorption processes can also be applied. Filter media naturally or industrially coated with manganese oxide are effective in adsorptive manganese removal. In this work, a layer of commercial manganese oxide coated medium was added to the top of an experimental sand/anthracite filter column to improve manganese removal. The coated layer was ca 28 cm thick (20% of the total filter depth) and the sand layer was 110 cm thick. The coated layer enhanced the manganese removal markedly. Manganese removal increased by over 91%, and < 0.02 mg/L of manganese remained in the treated water. Also iron removal was enhanced. Filters with added coated layer recovered faster than reference filter from filter backwashes. Sodium hypochlorite feed, which was tested in regeneration of the filter medium, had a slight negative effect on the filter performance.

  17. Hot coal gas desulfurization with manganese based sorbents. Quarterly report, June--September 1994

    SciTech Connect

    Hepworth, M.T.; Slimane, R.B.

    1994-11-01

    The focus of work being performed on hot coal gas desulfurization at the Morgantown Energy Technology Center is primarily in the use of zinc titanate sorbents; however, prior studies indicated that an alternate sorbent, manganese dioxide-containing ore in mixture with alumina (75 wt% ore + 25 wt% Al{sub 2}O{sub 3}) appears to be a strong contender to zinc-based sorbents. Manganese, for example, has a lower vapor pressure in the elemental state than zinc; hence, it is not as likely to undergo zinc-depletion from the sorbent surface upon loading and regeneration cycles. Also manganese oxide is less readily reduced to the elemental state than iron; hence, the range of reduction potentials for oxygen is somewhat greater than for zinc ferrite. In addition, thermodynamic analysis of the manganese-oxygen-sulfur system shows it to be less amenable to sulfation than zinc ferrite. Also manganese chlorides are much less stable and volatile than zinc chlorides. Potential also exists for utilization of manganese at higher temperatures than zinc ferrite or zinc titanate. This Eighth Quarterly Report documents progress in pelletizing and testing via thermo-gravimetric analysis of individual pellet formulations of manganese ore/alumina combinations and also manganese carbonate/alumina with two binders, dextrin and bentonite.

  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. Process for removing technetium from iron and other metals

    DOEpatents

    Leitnaker, James M.; Trowbridge, Lee D.

    1999-01-01

    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.

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

    DOEpatents

    Levi, D.H.; Nelson, A.J.; Ahrenkiel, R.K.

    1996-07-30

    A process is described 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. 12 figs.

  1. Manganese Dependent Anaerobic Oxidation of Methane

    NASA Astrophysics Data System (ADS)

    Beal, E.; House, C.

    2007-12-01

    Understanding the anaerobic oxidation is not only important for understanding hydrocarbon degradation but it also important for understanding the global carbon cycle. The anaerobic oxidation of methane (AOM) is a large sink for methane consuming 5-20% of today's methane flux (Valentine and Reeburgh, 2000), yet the requirements for this process are not well understood. It has been suggested that no other electron acceptors other than sulfate can be used in the AOM (Nauhaus, 2005). However, our new data suggests that manganese, in the form of birnessite, can be used as an electron acceptor instead of sulfate (Beal et al., in prep). Methane seep sediment from the Eel River Basin, CA was incubated with methane, 13C-labeled methane, and carbon dioxide. Because the net result of the AOM is the production of carbon dioxide from methane, the rate of the AOM in each of the incubations can be determined by measuring the incorporation of 13C in the carbon dioxide. Using this method, it was found that cultures incubated with nitrate showed inhibition of the AOM, while cultures incubated with iron gave inconclusive results. The only positive results that were found for alternate electron acceptors are the incubations that were given manganese and no sulfate, which showed methane oxidation. Further, when more manganese was injected into these incubations, the rate of AOM increased. Preliminary analysis of the microbial population using terminal restriction fragment length polymorphism (TRFLP) targeting the mcr gene showed an unidentified organism in these cultures. Future work with TRFLP, as well as clone libraries, will help to identify the organisms responsible for this process. Nauhaus, K., 2005, Environmental regulation of the anaerobic oxidation of methane: a comparison of ANME-I and ANME-II communities: Environmental microbiology, v. 7, p. 98. Valentine, D.L., and Reeburgh, W.S., 2000, New perspectives on anaerobic methane oxidation: Environmental Microbiology, v. 2, p

  2. Microtopography of manganese crusts

    NASA Astrophysics Data System (ADS)

    Morgan, Charles L.

    Quantitative examination of the seafloor surface roughness will be necessary for any design of equipment intended for use in collecting surface deposits such as cobalt-rich manganese crusts or nodules. Furthermore, it is an essential prerequisite to the confident interpretation of returns from high frequency side-scan and other acoustic systems. The objectives of the project were to develop the capability at the University of Hawaii of generating high resolution (less than 1 cm horizontal and vertical) topographic models of the seafloor from 35 mm stereo photographs; to produce such models from existing photographs of cobalt-rich manganese crust deposits; and to optimize the configuration of the existing Hawaii Undersea Research Laboratory (HURL) camera system for stereo photograph collection and correlation of acoustic data with the photographic ground-truth. These tasks were accomplished and have also led to the development of a follow-on project (MMTC/OBD Project 1512) dedicated to the simultaneous acquisition of both optical and side-scan acoustic data for future accurate determination of seabed microtopography.

  3. Nonstoichiometry of crystalline cadmium selenide

    SciTech Connect

    Kharif, Ya.L.; Brezhnev, V.Yu.; Kovtunenko, P.V.

    1987-08-01

    A highly sensitive physicochemical method is developed for determining the cadmium concentration (10/sup -5/ at. % for a 10 g sample weight), dissolved in cadmium selenide. The nonstoichiometry of cadmium selenide crystals is studied after high-temperature annealing at 870-1370/sup 0/K in cadmium vapor. For the first time, it is discovered that in the investigated crystals the dissolved cadmium exists primarily in the form of electrically neutral defects, which are presumably clusters of selenium vacancies with low mobility.

  4. Oral cadmium in mice carrying 5 versus 2 copies of the Slc39a8 gene: comparison of uptake, distribution, metal content, and toxicity.

    PubMed

    Schneider, Scott N; Liu, Zhiwei; Wang, Bin; Miller, Marian L; Afton, Scott E; Soleimani, Manoocher; Nebert, Daniel W

    2014-01-01

    The highly conserved human and mouse SLC39A8 gene encodes the divalent cation/bicarbonate symporter ZIP8 expressed ubiquitously in most cell types. Our bacterial artificial chromosome-transgenic BTZIP8-3 line has 3 additional copies of the Slc39a8 gene in addition to its constitutive diploid pair found in wild-type (WT) mice. In liver, kidney, lung, testis, gastrointestinal tract, and brain, BTZIP8-3 mice are known to express ∼2.5 times greater amounts of ZIP8, compared with WT mice. Herein we administered cadmium chloride (CdCl₂) in drinking water (100 mg/L through week 2, 200 mg/L through week 4, 400 mg/L through week 8, 800 mg/L through week 12, and 1600 mg/L through week 20, when the experiment was concluded). We postulated that Cd uptake and distribution--and, therefore, toxicity in certain tissues--would be enhanced in BTZIP8-3, compared with WT mice. BTZIP8-3 and WT groups ingested comparable amounts of Cd. Compared with WT, BTZIP8-3 mice showed tissue specific: increases in Cd, zinc, and manganese content and decreases in calcium content. Both Cd-exposed BTZIP8-3 and WT were similar in lower urinary pH; increased plasma alanine and aspartate aminotransferase activities; elevated iron and copper content in liver, kidney, lung, and testis; and higher blood urea nitrogen and kidney weight. Histological changes in liver, kidney, lung, and testis were minimal. In summary, at the daily oral Cd exposures chosen for this study, 5 versus 2 Slc39a8 gene copies result in no differences in Cd toxicity but do cause differences in tissue-specific content of Cd, zinc, manganese, calcium, iron, and copper.

  5. 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.

  6. Role of a binary metallic modifier in the determination of cadmium in graphite furnace atomic absorption spectrometry.

    PubMed

    Morimoto, Syun; Ashino, Tetsuya; Wagatsuma, Kazuaki

    2010-01-01

    In order to discuss the matrix modifier effect of palladium, iron, and a mixture of palladium and iron for the determination of cadmium in graphite-furnace atomic absorption spectrometry (GF-AAS), we measured the absorption profiles of a cadmium line at various compositions of these elements. Variations in the gas temperature were also estimated with the progress of atomization, by using a two-line method under the assumption of a Boltzmann distribution. The atomic absorption of cadmium appeared on the way of heating from the charring temperature to the atomizing temperature while the gas temperature was still low; it was thus considered that cadmium was atomized through direct conductive heating from the wall of the graphite furnace. Therefore, the effectiveness of modifiers for cadmium would be determined through any reactions on the furnace wall at the programmed charring and atomizing temperatures. The addition of iron, palladium, and an iron-palladium mixture all enhanced the absorption signal of cadmium compared to a pure cadmium sample; however, their effects were different from one another. Each addition of iron or palladium to the sample solution led to an enhancement of the cadmium absorbance, indicating that iron or palladium individually became an effective matrix modifier for the determination of cadmium. However, the addition of palladium was ineffective for the matrix modification in the coexistence of large amounts of iron. Although these phenomena are very complicated, and thus cannot be understood completely, any metallurgical reaction between the constituent elements during heating of the furnace wall, such as the formation of solid solutions and intermetallic compounds, would cause the effect of a matrix modifier in GF-AAS.

  7. Tellurium content of marine manganese oxides and other manganese oxides

    USGS Publications Warehouse

    Lakin, H.W.; Thompson, C.E.; Davidson, D.F.

    1963-01-01

    Tellurium in amounts ranging from 5 to 125 parts per million was present in all of 12 samples of manganese oxide nodules from the floor of the Pacific and Indian oceans. These samples represent the first recognized points of high tellurium concentration in a sedimentary cycle. The analyses may lend support to the theory that the minor-element content of seafloor manganese nodules is derived from volcanic emanations.

  8. Np and Pu Sorption to Manganese Oxide Minerals

    SciTech Connect

    Zhao, P; Johnson, M R; Roberts, S K; Zavarin, M

    2005-08-30

    Manganese oxide minerals are a significant component of the fracture lining mineralogy at Yucca Mountain (Carlos et al., 1993) and within the tuff-confining unit at Yucca Flat (Prothro, 1998), Pahute Mesa (Drellack et al., 1997), and other locations at the Nevada Test Site (NTS). Radionuclide sorption to manganese oxide minerals was not included in recent Lawrence Livermore National Laboratory (LLNL) hydrologic source term (HST) models which attempt to predict the migration behavior of radionuclides away from underground nuclear tests. However, experiments performed for the Yucca Mountain Program suggest that these minerals may control much of the retardation of certain radionuclides, particularly Np and Pu (Triay et al., 1991; Duff et al., 1999). As a result, recent HST model results may significantly overpredict radionuclide transport away from underground nuclear tests. The sorption model used in HST calculations performed at LLNL includes sorption to iron oxide, calcite, zeolite, smectite, and mica minerals (Zavarin and Bruton 2004a; 2004b). For the majority of radiologic source term (RST) radionuclides, we believe that this accounts for the dominant sorption processes controlling transport. However, for the case of Np, sorption is rather weak to all but the iron and manganese oxides (Figure 1). Thus, we can expect to significantly reduce predicted Np transport by accounting for Np sorption to manganese oxides. Similarly, Pu has been shown to be predominantly associated with manganese oxides in Yucca Mountain fractured tuffs (Duff et al., 1999). Recent results on colloid-facilitated Pu transport (Kersting and Reimus, 2003) also suggest that manganese oxide coatings on fracture surfaces may compete with colloids for Pu, thus reducing the effects of colloid-facilitated Pu transport (Figure 1b). The available data suggest that it is important to incorporate Np and Pu sorption to manganese oxides in reactive transport models. However, few data are available for

  9. Infrared birefringence spectra for cadmium sulfide and cadmium selenide.

    PubMed

    Chenault, D B; Chipman, R A

    1993-08-01

    Measurements of the birefringence spectra for cadmium sulfide and cadmium selenide from 2.5 to 16.5µm obtained with a rotating sample spectropolarimeter are presented. Because of the similarity in the birefringence spectra for cadmium sulfide and cadmium selenide, a highly achromatic IR retarder can be constructed from a combination of these materials. The ordinary and extraordinary refractive indices for cadmium sulfide are estimated in the region from 10.6 to 15 µm and for cadmium selenide from 10.6 to 16.5 µm by combining these birefringence data with an extrapolation of previous dispersion relations.

  10. Evaluation of Manganese Phosphate Coatings.

    DTIC Science & Technology

    1984-02-01

    84003 _____________ 4 . TTLE and -bitle)5. TYPE OF REPORT & PERIOD COVERED EVALUATION OF MANGANESE PHOSPHATE COATINGS Final 6. PERFORMING ORG. REPORT...rosion resistance of the Endurion phosphate was significantly superior to the 4 . basic manganese phosphate . Endurion phosphate with a Supplementary...OF CONTENTS Page STATEMENT OF THE PROBLEM 1 BACKGROUND 1 APPROACH TO THE PROBLEM 3 RESULTS 4 CONCLUSIONS 7 TABLES I. Falex Wear Life Test Procedure 8

  11. Mineral commodity profiles: Cadmium

    USGS Publications Warehouse

    Butterman, W.C.; Plachy, Jozef

    2004-01-01

    Overview -- Cadmium is a soft, low-melting-point metal that has many uses. It is similar in abundance to antimony and bismuth and is the 63d element in order of crustal abundance. Cadmium is associated in nature with zinc (and, less closely, with lead and copper) and is extracted mainly as a byproduct of the mining and processing of zinc. In 2000, it was refined in 27 countries, of which the 8 largest accounted for two-thirds of world production. The United States was the third largest refiner after Japan and China. World production in 2000 was 19,700 metric tons (t) and U.S. production was 1,890 t. In the United States, one company in Illinois and another in Tennessee refined primary cadmium. A Pennsylvania company recovered cadmium from scrap, mainly spent nickel-cadmium (NiCd) batteries. The supply of cadmium in the world and in the United States appears to be adequate to meet future industrial needs; the United States has about 23 percent of the world reserve base.

  12. Trace Metal Associations with Manganese-Rich Surface Coatings of Lead Service Lines

    EPA Science Inventory

    Analysis of lead service line samples from U. S. Environmental Protection Agency’s long-term research program to evaluate control and metal release from domestic drinking water service lines has revealed that Manganese-rich solids also contain Iron and sometimes Aluminum have fre...

  13. Manganese Deposits in the Artillery Mountains Region, Mohave County, Arizona

    USGS Publications Warehouse

    Lasky, S.G.; Webber, B.N.

    1944-01-01

    The manganese deposits of the Artillery Mountains region lie within an area of about 25 square miles between the Artillery and Rawhide Mountains, on the west side of the Bill Williams River in west-central Arizona. The richest croppings are on the northeast side of this area, among the foothills of the Artillery Mountains. They are 6 to 10 miles from Alamo. The nearest shipping points are Congress, about 50 miles to the east, and Aguila, about 50 miles to the southeast. The principal manganese deposits are part of a sequence of alluvial fan and playa material, probably of early Pliocene age, which were laid down in a fault basin. They are overlain by later Pliocene (?) basalt flows and sediments and by Quaternary basalt and alluvium. The Pliocene (?) rocks are folded into a shallow composite S1ncline ttat occupies the valley between the Artillery and Rawhide Mountains, and the folded rocks along either side of the valley, together with the overlying Quaternary basalt, are broken by faults that have produced a group of horsts, grabens, and step-fault blocks. The manganiferous beds, lie at two zones, 750 to 1,000 feet apart stratigraphically, each of which is locally as much as 300 to 400 feet thick. The main, or upper, zone contains three kinds of ore - sandstone ore, clay ore, and 'hard' ore. The sandstone and clay ores differ from the associated barren sandstone and clay, with which they are interlayered and into which they grade, primarily in containing a variable proportion of amorphous manganese oxides, besides iron oxides and clayey material such as are present in the barren beds. The 'hard' ore is sandstone that has been impregnated with opal and calcite and in which the original amorphous manganese oxides have been largely converted to psilomelane and manganite. The average manganese content of the sandstone and clay ores is between 3 and 4 percent and that of the 'hard' ore is between 6 and 7 percent. The ore contains an average of 3 percent of iron, 0

  14. 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.

  15. Crystallization and preliminary crystallographic analysis of manganese lipoxygenase.

    PubMed

    Wennman, Anneli; Oliw, Ernst H; Karkehabadi, Saeid

    2014-04-01

    Lipoxygenases constitute a family of nonhaem metal enzymes with catalytic iron or, occasionally, catalytic manganese. Lipoxygenases oxidize polyunsaturated fatty acids with position specificity and stereospecificity to hydroperoxides, which contribute to inflammation and the development of cancer. Little is known about the structural differences between lipoxygenases with Fe or Mn and the metal-selection mechanism. A Pichia pastoris expression system was used for the production of the manganese lipoxygenase of the take-all fungus of wheat, Gaeumannomyces graminis. The active enzyme was treated with α-mannosidase, purified to apparent homogeneity and subjected to crystal screening and X-ray diffraction. The crystals diffracted to 2.6 Å resolution and belonged to space group C2, with unit-cell parameters a = 226.6, b = 50.6, c = 177.92 Å, β = 91.70°.

  16. Iron Test

    MedlinePlus

    ... detect and help diagnose iron deficiency or iron overload. In people with anemia , these tests can help ... also be ordered when iron deficiency or iron overload is suspected. Early iron deficiency often goes unnoticed. ...

  17. Hot coal gas desulfurization with manganese-based sorbents. Annual report, September 1992--September 1993

    SciTech Connect

    Hepworth, M.T.

    1993-12-01

    The focus of work being performed on Hot Coal Gas Desulfurization at the Morgantown Energy Technology Center is primarily in the use of zinc ferrite and zinc titanate sorbents; however, prior studies at the US Steel Fundamental Research Laboratories in Monroeville, PA, by E. T. Turkdogan indicated that an alternate sorbent, manganese dioxide-containing ore in mixture with alumina (75 wt % ore + 25 wt % Al{sub 2}O{sub 3}) may be a viable alternative to zinc-based sorbents. Manganese, for example, has a lower vapor pressure in the elemental state than zinc hence it is not as likely to undergo depletion from the sorbent surface upon loading and regeneration cycles. Also manganese oxide is less readily reduced to the elemental state than iron hence the range of reduction potentials for oxygen is somewhat greater than for zinc ferrite. In addition, thermodynamic analysis of the manganese-oxygen-sulfur system shows it to be less amenable to sulfation than zinc ferrite. Potential also exists for utilization of manganese at higher temperatures than zinc ferrite or zinc titanate. This Annual Topical Report documents progress in pelletizing and testing via thermo-gravimetric analysis of individual pellet formulations of manganese ore/ alumina combinations and also manganese carbonate/alumina with two binders, dextrin and bentonite. It includes the prior Quarterly Technical Reports which indicate that the manganese carbonate material, being of higher purity than the manganese ore, has a higher degree of sulfur capacity and more rapid absorption kinetics. A 2-inch fixed-bed reactor has been fabricated and is now ready for subjecting pellets to cyclic loading and regeneration.

  18. Hot Coal Gas Desulfurization with manganese based sorbents. Quarterly report, August 1, 1993--September 30, 1993

    SciTech Connect

    Hepworth, M.T.

    1993-10-01

    The focus of work being performed on Hot Coal Gas Desulfurization at the Morgantown Energy Technology Center is primarily in the use of zinc ferrite and zinc titanate sorbents; however, prior studies at the US Steel Fundamental Research Laboratories in Monroeville, PA, by E. T. Turkdogan indicated that an alternate sorbent, manganese dioxide-containing ore in mixture with alumina (75 wt % ore + 25 wt % Al{sub 2}O{sub 3}) may be a viable alternative to zinc-based sorbents. Manganese, for example, has a lower vapor pressure in the elemental state than zinc hence it is not as likely to undergo depletion from the sorbent surface upon loading and regeneration cycles. Also manganese oxide is less readily reduced to the elemental state than iron hence the range of reduction potentials for oxygen is somewhat greater than for zinc ferrite. In addition, thermodynamic analysis of the manganese-oxygen-sulfur system shows it to be less amenable to sulfation than zinc ferrite. Potential also exists for utilization of manganese at higher temperatures than zinc ferrite or zinc titanate. This report documents progress in pelletizing and testing via thermogravimetric analysis of individual pellet formulations of manganese ore/alumina combinations and also manganese carbonate/alumina with two binders, dextrin and bentonite. Preliminary results indicate that the manganese carbonate material, being of higher purity than the manganese ore, has a higher degree of sulfur capacity and more rapid absorption kinetics. A 2-inch fixed-bed reactor has been fabricated and is now ready for subjecting pellets to cyclic loading and regeneration.

  19. How iron controls iron.

    PubMed

    Kühn, Lukas C

    2009-12-01

    Cells regulate iron homeostasis by posttranscriptional regulation of proteins responsible for iron uptake and storage. This requires RNA-binding activity of iron-regulatory proteins, IRP1 and IRP2. Two studies recently published in Science by Vashisht et al. (2009) and Salahudeen et al. (2009) reveal how cells adjust IRP2 activity.

  20. Bacteriology of Manganese Nodules

    PubMed Central

    Trimble, R. B.; Ehrlich, H. L.

    1968-01-01

    MnO2 reduction by aerobic growing cultures of Bacillus 29 and coccus 32, isolated from ferromanganese nodules, was assessed for 7 days. A 1-day lag was observed before the onset of MnO2 reduction by either culture. Addition of HgCl2 to a final concentration of about 10-3 M caused a rapid cessation of MnO2 reduction by the growing cultures. Neither culture reduced MnO2 when grown under continued anaerobiosis from the start of an experiment. However, if conditions were made anaerobic after MnO2 reduction was initiated, reduction continued at a rate only slightly lower than that under aerobic conditions. Resting-cell cultures reduced MnO2 equally well aerobically and anaerobically, provided that ferricyanide was present to serve as electron carrier. These findings showed that oxygen is needed for culture adaptation to MnO2 reduction, and that oxygen does not interfere with microbial MnO2 reduction itself. Both cultures caused sharp drops in the pH of the medium during MnO2 reduction: with coccus 32, during the entire incubation time; with Bacillus 29, for the first 3 days. The Eh of the medium fluctuated with either culture and never fell below 469 mv with Bacillus 29 and below 394 mv with coccus 32. The rates of glucose consumption and Mn2+ release by Bacillus 29 and coccus 32 were fairly constant, but the rates of lactate and pyruvate production were not. Although acid production undoubtedly helped in the reduction of pyrolusite (MnO2) by the bacteria, it did not appear to be important in the reduction of manganese oxide in ferromanganese nodules, as shown by the results with a nodule enrichment. PMID:16349802

  1. Polarization of IRON-REGULATED TRANSPORTER 1 (IRT1) to the plant-soil interface plays crucial role in metal homeostasis.

    PubMed

    Barberon, Marie; Dubeaux, Guillaume; Kolb, Cornelia; Isono, Erika; Zelazny, Enric; Vert, Grégory

    2014-06-03

    In plants, the controlled absorption of soil nutrients by root epidermal cells is critical for growth and development. IRON-REGULATED TRANSPORTER 1 (IRT1) is the main root transporter taking up iron from the soil and is also the main entry route in plants for potentially toxic metals such as manganese, zinc, cobalt, and cadmium. Previous work demonstrated that the IRT1 protein localizes to early endosomes/trans-Golgi network (EE/TGN) and is constitutively endocytosed through a monoubiquitin- and clathrin-dependent mechanism. Here, we show that the availability of secondary non-iron metal substrates of IRT1 (Zn, Mn, and Co) controls the localization of IRT1 between the outer polar domain of the plasma membrane and EE/TGN in root epidermal cells. We also identify FYVE1, a phosphatidylinositol-3-phosphate-binding protein recruited to late endosomes, as an important regulator of IRT1-dependent metal transport and metal homeostasis in plants. FYVE1 controls IRT1 recycling to the plasma membrane and impacts the polar delivery of this transporter to the outer plasma membrane domain. This work establishes a functional link between the dynamics and the lateral polarity of IRT1 and the transport of its substrates, and identifies a molecular mechanism driving polar localization of a cell surface protein in plants.

  2. Polarization of IRON-REGULATED TRANSPORTER 1 (IRT1) to the plant-soil interface plays crucial role in metal homeostasis

    PubMed Central

    Barberon, Marie; Dubeaux, Guillaume; Kolb, Cornelia; Isono, Erika; Zelazny, Enric; Vert, Grégory

    2014-01-01

    In plants, the controlled absorption of soil nutrients by root epidermal cells is critical for growth and development. IRON-REGULATED TRANSPORTER 1 (IRT1) is the main root transporter taking up iron from the soil and is also the main entry route in plants for potentially toxic metals such as manganese, zinc, cobalt, and cadmium. Previous work demonstrated that the IRT1 protein localizes to early endosomes/trans-Golgi network (EE/TGN) and is constitutively endocytosed through a monoubiquitin- and clathrin-dependent mechanism. Here, we show that the availability of secondary non-iron metal substrates of IRT1 (Zn, Mn, and Co) controls the localization of IRT1 between the outer polar domain of the plasma membrane and EE/TGN in root epidermal cells. We also identify FYVE1, a phosphatidylinositol-3-phosphate-binding protein recruited to late endosomes, as an important regulator of IRT1-dependent metal transport and metal homeostasis in plants. FYVE1 controls IRT1 recycling to the plasma membrane and impacts the polar delivery of this transporter to the outer plasma membrane domain. This work establishes a functional link between the dynamics and the lateral polarity of IRT1 and the transport of its substrates, and identifies a molecular mechanism driving polar localization of a cell surface protein in plants. PMID:24843126

  3. Manganese uptake and streptococcal virulence.

    PubMed

    Eijkelkamp, Bart A; McDevitt, Christopher A; Kitten, Todd

    2015-06-01

    Streptococcal solute-binding proteins (SBPs) associated with ATP-binding cassette transporters gained widespread attention first as ostensible adhesins, next as virulence determinants, and finally as metal ion transporters. In this mini-review, we will examine our current understanding of the cellular roles of these proteins, their contribution to metal ion homeostasis, and their crucial involvement in mediating streptococcal virulence. There are now more than 35 studies that have collected structural, biochemical and/or physiological data on the functions of SBPs across a broad range of bacteria. This offers a wealth of data to clarify the formerly puzzling and contentious findings regarding the metal specificity amongst this group of essential bacterial transporters. In particular we will focus on recent findings related to biological roles for manganese in streptococci. These advances will inform efforts aimed at exploiting the importance of manganese and manganese acquisition for the design of new approaches to combat serious streptococcal diseases.

  4. Manganese abundances in Galactic bulge red giants

    NASA Astrophysics Data System (ADS)

    Barbuy, B.; Hill, V.; Zoccali, M.; Minniti, D.; Renzini, A.; Ortolani, S.; Gómez, A.; Trevisan, M.; Dutra, N.

    2013-11-01

    Context. Manganese is mainly produced in type II SNe during explosive silicon burning, in incomplete Si-burning regions, and depends on several nucleosynthesis environment conditions, such as mass cut between the matter ejected and falling back onto the remnant, electron and neutron excesses, mixing fallback, and explosion energy. Manganese is also produced in type Ia SNe. Aims: The aim of this work is the study of abundances of the iron-peak element Mn in 56 bulge giants, among which 13 are red clump stars. Four bulge fields along the minor axis are inspected. The study of abundances of Mn-over-Fe as a function of metallicity in the Galactic bulge may shed light on its production mechanisms. Methods: High-resolution spectra were obtained using the FLAMES+UVES spectrograph on the Very Large Telescope. The spectra were obtained within a program to observe 800 stars using the GIRAFFE spectrograph, together with the present UVES spectra. Results: We aim at identifying the chemical evolution of manganese, as a function of metallicity, in the Galactic bulge. We find [Mn/Fe] ~ -0.7 at [Fe/H] ~ -1.3, increasing to a solar value at metallicities close to solar, and showing a spread around - 0.7 ≲ [Fe/H] ≲ -0.2, in good agreement with other work on Mn in bulge stars. There is also good agreement with chemical evolution models. We find no clear difference in the behaviour of the four bulge fields. Whereas [Mn/Fe] vs. [Fe/H] could be identified with the behaviour of the thick disc stars, [Mn/O] vs. [O/H] has a behaviour running parallel, at higher metallicities, compared to thick disc stars, indicating that the bulge enrichment might have proceeded differently from that of the thick disc. Observations collected at the European Southern Observatory, Paranal, Chile (ESO programmes 71.B-0617A, 73.B0074A, and GTO 71.B-0196).Tables 1-6 and Figs. 1-6 are available in electronic form at http://www.aanda.org

  5. Cadmium in the aquatic environment

    SciTech Connect

    Nriagu, J.O.; Sprague, J.B.

    1987-01-01

    This volume presents a comprehensive account of current research on the chemistry and toxicology of cadmium in natural waters. The first four chapters focus on the sources (natural vs. anthropogenic), behavior, and fate of cadmium in natural waters. These are followed by three chapters on the biocycling and effects of cadmium on freshwater biota. The ecotoxicity of cadmium to marine biota are covered by the next two chapters. The final chapter presents a succinct review of the analytical chemistry of cadmium in natural waters.

  6. Cadmium sulphide solar cell

    SciTech Connect

    Bassett, P.J.; Verheijen, A.W.

    1984-07-31

    The invention relates to the manufacture of cadmium sulphide solar cells. A cell is formed of a glass substrate 10, a front contact 12 made, for example, of tin oxide, a cadmium sulphide layer 14 and a copper sulphide layer 16, the junction between the layers 14 and 16 is photovoltaic. In order to form a rear contact 18 on the copper sulphide layer, the invention proposes vapor depositing a mixed layer of copper and copper oxide onto the sulphide layer. The invention also describes a method of heat treatment following the formation of the rear contact in order to optimise the electrical performance of the cell.

  7. On the manganese content of cosmic flakes from deep-sea sediments

    NASA Technical Reports Server (NTRS)

    Utech, K.

    1973-01-01

    Cosmic flakes belong to the category of cosmic microparticles. They occur together with cosmic spherules in sediments. These flakes appear to represent ablation products of iron meteorites burnt away during the passage of a meteorite through the atmosphere by friction against air molecules. Microprobe analyses of flakes from deep sea deposits proved the particles to consist of magnetite which in most cases had been altered into maghemite in the outer zones. This is in agreement with the assumption that they represent fragments of fusion crust of iron meteorites. Most of the flakes, however, contained a small percentage of manganese. This element is not a common constituent of iron meteorites. An attempt is made to explain the presence of manganese in flakes and its absence in cosmic spherules.

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

    SciTech Connect

    Kippler, M.; Goessler, W.; Nermell, B.; Ekstroem, E.C.; Loennerdal, B.; El Arifeen, S.; Vahter, M.

    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.

  9. SEPARATING PROTOACTINIUM WITH MANGANESE DIOXIDE

    DOEpatents

    Seaborg, G.T.; Gofman, J.W.; Stoughton, R.W.

    1958-04-22

    The preparation of U/sup 235/ and an improved method for isolating Pa/ sup 233/ from foreign products present in neutronirradiated thorium is described. The method comprises forming a solution of neutron-irradiated thorium together with a manganous salt, then adding potassium permanganate to precipitate the manganese as manganese dioxide whereby protoactinium is carried down with the nnanganese dioxide dissolving the precipitate, adding a soluble zirconium salt, and adding phosphate ion to precipitate zirconium phosphate whereby protoactinium is then carried down with the zirconium phosphate to effect a further concentration.

  10. CADMIUM PHOSPHATE GLASS

    DOEpatents

    Carpenter, H.W.; Johnson, P.D.

    1963-04-01

    A method of preparing a cadmium phosphate glass that comprises providing a mixture of solid inorganic compounds of cadmuim and phosphate having vaporizable components and heating the resulting composition to a temperature of at least 850 un. Concent 85% C is presented. (AEC)

  11. Cadmium plating replacements

    SciTech Connect

    Nelson, M.J.; Groshart, E.C.

    1995-03-01

    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.

  12. 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.

  13. 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.

  14. Carbothermic reduction of U.S. ferruginous manganese resources

    NASA Astrophysics Data System (ADS)

    Hansen, Jeffrey S.; Tress, Jack E.; Nafziger, Ralph H.

    1993-04-01

    The U.S. Bureau of Mines conducted laboratory-scale research to determine the degree to which U.S. ferruginous manganese resources can be reduced to produce an acceptable ferromanganese for alloying iron and steel. The objective was to evaluate the feasibility of prereduction (reduction prior to melting) of such resources as an alternative to direct smelting. As part of the Bureau's goal to recover metal values economically and efficiently from U.S. resources, ferruginous manganese oxide materials from five deposits were reduced with low-cost and lower grade carbonaceous reductants at temperatures ranging from 600°C to 1,050°C for holding periods from 30 min. to 90 min. Greater than 95% net reduction of the tetravalent and trivalent states of manganese to the divalent state (which represents a typical feed for an electric arc furnace producing ferromanganese) was achieved at 750°C using inexpensive blacksmith coal on samples that did not contain significant amounts of silica.

  15. Iron Chelation

    MedlinePlus

    ... iron overload and need treatment. What is iron overload? Iron chelation therapy is used when you have ... may want to perform: How quickly does iron overload happen? This is different for each person. It ...

  16. Effects of iron status on transpulmonary transport and tissue distribution of Mn and Fe.

    PubMed

    Brain, Joseph D; Heilig, Elizabeth; Donaghey, Thomas C; Knutson, Mitchell D; Wessling-Resnick, Marianne; Molina, Ramon M

    2006-03-01

    Manganese transport into the blood can result from inhaling metal-containing particles. Intestinal manganese and iron absorption is mediated by divalent metal transporter 1 (DMT1) and is upregulated in iron deficiency. Since iron status alters absorption of Fe and Mn in the gut, we tested the hypothesis that iron status may alter pulmonary transport of these metals. DMT1 expression in the lungs was evaluated to explore its role in metal transport. The pharmacokinetics of intratracheally instilled 54Mn or 59Fe in repeatedly bled or iron oxide-exposed rats were compared with controls. Iron oxide exposure caused a reduction in pulmonary transport of 54Mn and 59Fe, and decreased uptake in other major organs. Low iron status from repeated bleeding also reduced pulmonary transport of iron but not of manganese. However, uptake of manganese in the brain and of iron in the spleen increased in bled rats. DMT1 transcripts were detected in airway epithelium, alveolar macrophages, and bronchial-associated lymphoid tissue in all rats. Focal increases were seen in particle-containing macrophages and adjacent epithelial cells, but no change was observed in bled rats. Although lung DMT1 expression did not correlate with iron status, differences in pharmacokinetics of instilled metals suggest that their potential toxicity can be modified by iron status.

  17. Distribution of manganese along a section extending from the coast to offshore in the eastern North Atlantic.

    NASA Astrophysics Data System (ADS)

    Laan, P.; Blain, S.; Timmermans, K.; Debaar, H.

    2003-04-01

    In order to better understand and quantify the input of trace elements from the sediments in the water column, a detailed section from the coast to offshore has been studied in the eastern north Atlantic. The cruise took place in March 2002, on board R/V Pelagia, as part of the European Union project IRONAGES. This section, extended from a depth of 96 meter towards 4750 meter. Fifteen stations have been sampled intensively for several trace elements. The stations have been sampled for dissolved manganese, iron and major nutrients analyses. GoFlo bottles mounted on a kevlar cable were used for clean seawater sampling in the water column. Samples were filtered on-line through a 0.2 μm cartridge. The samples collected for the dissolved manganese analyses were acidified on board and stored for later analysis in the home laboratory. The dissolved manganese concentration were measured using FIA analysis with in-line preconcentration (onto 8 HQ resin) and colorimetric determination. Concentrations of dissolved manganese were elevated in surface waters and near the sediments. In addition, a gradient from coast to offshore was observed. Near shore dissolved manganese concentrations were higher than those offshore. These results corroborate previous surveys in which it was demonstrated that aelion input as well as benthic upwelling can cause elevated manganese concentrations. The results will be further discussed in the light of the dissolved iron and major nutrient analyses.

  18. The Study of Local Effect of Manganese on Microstructure Development of Admixed Fe-Mn-C Sintered Steels

    NASA Astrophysics Data System (ADS)

    Bidulský, Róbert; Hryha, Eduard; Bidulská, Jana

    2016-10-01

    The present paper is focused on the effect of manganese on microstructure development of admixed Fe-Mn-C sintered steels along with diffusion characteristics of manganese in the iron matrix. Admixed systems were prepared on the base of sponge iron powder, with addition of 0.3% C and 3% Mn added as ferromanganese. Sintering at 1,023, 1,173, 1,323, 1,423 and 1,473 K for 180 s was carried out in laboratory tube furnace in an atmosphere of pure gases mixture 25% N2+75% H2 with the dew point of 243 K. The results show that admixed sintered manganese steels exhibit heterogeneity of microstructure due to the local chemical heterogeneities of these materials, in particular for those areas with a high manganese concentration. On the basis of calculation of manganese apparent diffusion coefficient and penetration depth, results reveal that diffusion-induced grain boundary migration (DIGM) is the dominant alloying mechanism in sintered manganese steels.

  19. Method of epitaxially depositing cadmium sulfide

    NASA Technical Reports Server (NTRS)

    Hawrylo, Frank Z. (Inventor)

    1980-01-01

    A single crystal layer of either cadmium sulfide or an alloy of cadmium sulfide and indium phosphide is epitaxially deposited on a substrate of cadmium sulfide by liquid phase epitaxy using indium as the solvent.

  20. Structural basis for the metal-selective activation of the manganese transport regulator of Bacillus subtilis.

    PubMed

    Kliegman, Joseph I; Griner, Sarah L; Helmann, John D; Brennan, Richard G; Glasfeld, Arthur

    2006-03-21

    The manganese transport regulator (MntR) of Bacillus subtilis is activated by Mn(2+) to repress transcription of genes encoding transporters involved in the uptake of manganese. MntR is also strongly activated by cadmium, both in vivo and in vitro, but it is poorly activated by other metal cations, including calcium and zinc. The previously published MntR.Mn(2+) structure revealed a binuclear complex of manganese ions with a metal-metal separation of 3.3 A (herein designated the AB conformer). Analysis of four additional crystal forms of MntR.Mn(2+) reveals that the AB conformer is only observed in monoclinic crystals at 100 K, suggesting that this conformation may be stabilized by crystal packing forces. In contrast, monoclinic crystals analyzed at room temperature (at either pH 6.5 or pH 8.5), and a second hexagonal crystal form (analyzed at 100 K), all reveal the shift of one manganese ion by 2.5 A, thereby leading to a newly identified conformation (the AC conformer) with an internuclear distance of 4.4 A. Significantly, the cadmium and calcium complexes of MntR also contain binuclear complexes with a 4.4 A internuclear separation. In contrast, the zinc complex of MntR contains only one metal ion per subunit, in the A site. Isothermal titration calorimetry confirms the stoichiometry of Mn(2+), Cd(2+), and Zn(2+) binding to MntR. We propose that the specificity of MntR activation is tied to productive binding of metal ions at two sites; the A site appears to act as a selectivity filter, determining whether the B or C site will be occupied and thereby fully activate MntR.

  1. Essential and nonessential elements in nestling rooks Corvus frugilegus from eastern Poland with a special emphasis on their high cadmium contamination.

    PubMed

    Orłowski, Grzegorz; Kamiński, Piotr; Kasprzykowski, Zbigniew; Zawada, Zbigniew; Koim-Puchowska, Beata; Szady-Grad, Małgorzata; Klawe, Jacek J

    2012-11-01

    Concentration of minerals (sodium, potassium, calcium [Ca], magnesium, iron [Fe], copper, zinc [Zn], manganese [Mn], and cobalt) as well as toxic metals (cadmium [Cd], lead [Pb]) were determined in five tissues (liver, lung, kidney, muscle, and bone) of nestling rooks (Corvus frugilegus; 1 to 13 days old) found dead in seven breeding colonies in eastern Poland. Cd concentration in all analyzed tissues was in the narrow range of 17.0-17.2 mg/kg dry weight (dw) Cd, which in the light of the literature data indicates acute contamination by this toxic metal. Similarly, we found increased levels of Pb, which in all tissues ranged between 5.0 and 6.2 mg/kg dw. Results of multivariate general linear model (GLM) testing of the effect of three variables (tissue type, colony, and nestling age) on tissue concentrations of various metals showed significance for Fe, Cu, Zn, and Mn. Only concentrations of Ca, Fe, and Zn differed significantly between the analyzed tissues. GLM analysis did not show any statistically significant differences in tissue levels of minerals and both toxic metals among examined rookeries, which indicates the widespread presence of nonpoint Cd and Pb pollution linked to agricultural activity and similar levels of these inorganic contaminants on crop fields (feeding grounds) around breeding colonies. We concluded that high levels of both toxic metals, Cd and Pb, probably resulting from the diet of nestling rooks, are based mainly on a diet of ground-dwelling beetles gathered on crop fields.

  2. Synthesis, characterization, optical and sensing property of manganese oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Manigandan, R.; Suresh, R.; Giribabu, K.; Vijayalakshmi, L.; Stephen, A.; Narayanan, V.

    2014-01-01

    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.

  3. Synthesis, characterization, optical and sensing property of manganese oxide nanoparticles

    SciTech Connect

    Manigandan, R.; Suresh, R.; Giribabu, K.; Narayanan, V.; Vijayalakshmi, L.; Stephen, A.

    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.

  4. Characterization of the manganese O2-evolving complex and the iron-quinone acceptor complex in photosystem II from a thermophilic cyanobacterium by electron paramagnetic resonance and X-ray absorption spectroscopy.

    PubMed

    McDermott, A E; Yachandra, V K; Guiles, R D; Cole, J L; Dexheimer, S L; Britt, R D; Sauer, K; Klein, M P

    1988-05-31

    The Mn donor complex in the S1 and S2 states and the iron-quinone acceptor complex (Fe2+-Q) in O2-evolving photosystem II (PS II) preparations from a thermophilic cyanobacterium, Synechococcus sp., have been studied with X-ray absorption spectroscopy and electron paramagnetic resonance (EPR). Illumination of these preparations at 220-240 K results in formation of a multiline EPR signal very similar to that assigned to a Mn S2 species observed in spinach PS II, together with g = 1.8 and 1.9 EPR signals similar to the Fe2+-QA- acceptor signals seen in spinach PS II. Illumination at 110-160 K does not produce the g = 1.8 or 1.9 EPR signals, nor the multiline or g = 4.1 EPR signals associated with the S2 state of PS II in spinach; however, a signal which peaks at g = 1.6 appears. The most probable assignment of this signal is an altered configuration of the Fe2+-QA- complex. In addition, no donor signal was seen upon warming the 140 K illuminated sample to 215 K. Following continuous illumination at temperatures between 140 and 215 K, the average X-ray absorption Mn K-edge inflection energy changes from 6550 eV for a dark-adapted (S1) sample to 6551 eV for the illuminated (S2) sample. The shift in edge inflection energy indicates an oxidation of Mn, and the absolute edge inflection energies indicate an average Mn oxidation state higher than Mn(II). Upon illumination a significant change was observed in the shape of the features associated with 1s to 3d transitions. The S1 spectrum resembles those of Mn(III) complexes, and the S2 spectrum resembles those of Mn(IV) complexes. The extended X-ray absorption fine structure (EXAFS) spectrum of the Mn complex is similar in the S1 and S2 states. Simulations indicate O or N ligands at 1.75 +/- 0.05 A, transition metal neighbor(s) at 2.73 +/- 0.05 A, which are assumed to be Mn, and terminal ligands which are probably N and O at a range of distances around 2.2 A. The Mn-O bond length of 1.75 A and the transition metal at 2.7 A

  5. Size and compositionally controlled manganese ferrite nanoparticles with enhanced magnetization

    NASA Astrophysics Data System (ADS)

    Vamvakidis, K.; Sakellari, D.; Angelakeris, M.; Dendrinou-Samara, C.

    2013-06-01

    A facile solvothermal approach was used to synthesize stable, superparamagnetic manganese ferrite nanoparticles with relatively small sizes (<10 nm) and enhanced magnetic features. Tetraethylene glycol has been used in all the syntheses as a biocompatible and stabilizing agent. By varying the oxidation state of manganese precursor, Mn(acac)2 to Mn(acac)3, different sizes, 8 and 5 nm, of MnFe2O4 nanoparticles were obtained respectively, while by tailoring the synthetic conditions iron-rich Mn0.77Fe2.23O4 nanoparticles have been isolated with identical sizes and enhanced saturation magnetization. The magnetization values increased from 58.2 to 68.3 Am2/kg and from 53.3 to 60.2 Am2/kg for the nanoparticles of 8 and 5 nm, respectively. Blocking temperature ( T B), ranging from 80 to 180 K, and anisotropy constant ( K eff), ranging from 1.5 × 105 to 4.9 × 105 J/m3, were found higher for the iron-rich samples and associated with size and composition effects.

  6. Cadmium sulfite hexahydrate revisited

    PubMed Central

    Baggio, Sergio; Ibáñez, Andrés; Baggio, Ricardo

    2008-01-01

    The present structural revision of the title compound, tetra­cadmium tetra­sulfite hexa­hydrate, [Cd4(SO3)4(H2O)5]·H2O, is a low-temperature upgrade (T = 100 K and R = 0.017) of the original room-temperature structure reported by Kiers & Vos [Cryst. Struct. Commun. (1978). 7, 399–403; T = 293 K and R = 0.080). The compound is a three-dimensional polymer with four independent cadmium centres, four sulfite anions and six water mol­ecules, five of them coordinated to two cadmium centres and the remaining one an unbound solvent mol­ecule which completes the asymmetric unit. There are two types of cadmium environment: CdO8 (through four chelating sulfite ligands) and CdO6 (by way of six monocoordinated ligands). The former groups form planar arrays [parallel to (001) and separated by half a unit cell translation along c], made up of chains running along [110] and [10], respectively. These chains are, in turn, inter­connected both in an intra­planar as well as in an inter­planar fashion by the latter CdO6 polyhedra into a tight three-dimensional framework. There is, in addition, an extensive network of hydrogen bonds, in which all 12 water H atoms act as donors and eight O atoms from all four sulfite groups and two water mol­ecules act as acceptors. PMID:21202728

  7. Manganese Research Health Project (MHRP)

    DTIC Science & Technology

    2009-02-01

    of a GLP compliant micronucleus assay in mice according to the OECD Guideline for the Testing of Chemicals, OECD 474: Mammalian Erythrocyte... Micronucleus Test . Experimental Design The basic experimental design used at ILS and proposed for the definitive in vivo micronucleus assay in manganese...regimen, would be expected to produce lethality”. The limit dose for the in vivo micronucleus assay based on OECD 474 is 2000 mg/kg and testing in a

  8. Microbial Formation of Manganese Oxides

    PubMed Central

    Greene, Anthony C.; Madgwick, John C.

    1991-01-01

    Microbial manganese oxidation was demonstrated at high Mn2+ concentrations (5 g/liter) in bacterial cultures in the presence of a microalga. The structure of the oxide produced varied depending on the bacterial strain and mode of culture. A nonaxenic, acid-tolerant microalga, a Chlamydomonas sp., was found to mediate formation of manganite (γ-MnOOH). Bacteria isolated from associations with crude cultures of this alga grown in aerated bioreactors formed disordered γ-MnO2 from Mn2+ at concentrations of 5 g/liter over 1 month, yielding 3.3 g of a semipure oxide per liter. All algal-bacterial cultures removed Mn2+ from solution, but only those with the highest removal rates formed an insoluble oxide. While the alga was an essential component of the reaction, a Pseudomonas sp. was found to be primarily responsible for the formation of a manganese precipitate. Medium components—algal biomass and urea—showed optima at 5.7 and 10 g/liters, respectively. The scaled-up culture (50 times) gave a yield of 22.3 g (53 mg/liter/day from a 15-liter culture) of semipure disordered γ-MnO2, identified by X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy, and had a manganese oxide O/Mn ratio of 1.92. The Mn(IV) content in the oxide was low (30.5%) compared with that of mined or chemically formed γ-MnO2 (ca. 50%). The shortfall in the bacterial oxide manganese content was due to biological and inorganic contaminants. FTIR spectroscopy, transmission electron microscopy, and electron diffraction studies have identified manganite as a likely intermediate product in the formation of disordered γ-MnO2. PMID:16348459

  9. Current status of cadmium as an environmental health problem

    SciTech Connect

    Jaerup, Lars Akesson, Agneta

    2009-08-01

    Cadmium is a toxic metal occurring in the environment naturally and as a pollutant emanating from industrial and agricultural sources. Food is the main source of cadmium intake in the non-smoking population. The bioavailability, retention and toxicity are affected by several factors including nutritional status such as low iron status. Cadmium is efficiently retained in the kidney (half-time 10-30 years) and the concentration is proportional to that in urine (U-Cd). Cadmium is nephrotoxic, initially causing kidney tubular damage. Cadmium can also cause bone damage, either via a direct effect on bone tissue or indirectly as a result of renal dysfunction. After prolonged and/or high exposure the tubular injury may progress to glomerular damage with decreased glomerular filtration rate, and eventually to renal failure. Furthermore, recent data also suggest increased cancer risks and increased mortality in environmentally exposed populations. Dose-response assessment using a variety of early markers of kidney damage has identified U-Cd points of departure for early kidney effects between 0.5 and 3 {mu}g Cd/g creatinine, similar to the points of departure for effects on bone. It can be anticipated that a considerable proportion of the non-smoking adult population has urinary cadmium concentrations of 0.5 {mu}g/g creatinine or higher in non-exposed areas. For smokers this proportion is considerably higher. This implies no margin of safety between the point of departure and the exposure levels in the general population. Therefore, measures should be put in place to reduce exposure to a minimum, and the tolerably daily intake should be set in accordance with recent findings.

  10. Alteration at translational but not transcriptional level of transferrin receptor expression following manganese exposure at the blood-CSF barrier in vitro

    SciTech Connect

    Li, G. Jane; Zhao Qiuqu; Zheng Wei . E-mail: wzheng@purdue.edu

    2005-06-01

    Manganese exposure alters iron homeostasis in blood and cerebrospinal fluid (CSF), possibly by acting on iron transport mechanisms localized at the blood-brain barrier and/or blood-CSF barrier. This study was designed to test the hypothesis that manganese exposure may change the binding affinity of iron regulatory proteins (IRPs) to mRNAs encoding transferrin receptor (TfR), thereby influencing iron transport at the blood-CSF barrier. A primary culture of choroidal epithelial cells was adapted to grow on a permeable membrane sandwiched between two culture chambers to mimic blood-CSF barrier. Trace {sup 59}Fe was used to determine the transepithelial transport of iron. Following manganese treatment (100 {mu}M for 24 h), the initial flux rate constant (K {sub i}) of iron was increased by 34%, whereas the storage of iron in cells was reduced by 58%, as compared to controls. A gel shift assay demonstrated that manganese exposure increased the binding of IRP1 and IRP2 to the stem loop-containing mRNAs. Consequently, the cellular concentrations of TfR proteins were increased by 84% in comparison to controls. Assays utilizing RT-PCR, quantitative real-time reverse transcriptase-PCR, and nuclear run off techniques showed that manganese treatment did not affect the level of heterogeneous nuclear RNA (hnRNA) encoding TfR, nor did it affect the level of nascent TfR mRNA. However, manganese exposure resulted in a significantly increased level of TfR mRNA and reduced levels of ferritin mRNA. Taken together, these results suggest that manganese exposure increases iron transport at the blood-CSF barrier; the effect is likely due to manganese action on translational events relevant to the production of TfR, but not due to its action on transcriptional, gene expression of TfR. The disrupted protein-TfR mRNA interaction in the choroidal epithelial cells may explain the toxicity of manganese at the blood-CSF barrier.

  11. 21 CFR 184.1461 - Manganese sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... dioxide in sulfuric acid, and the roasting of pyrolusite (MnO2) ore with solid ferrous sulfate and coal... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Manganese sulfate. 184.1461 Section 184.1461 Food... Specific Substances Affirmed as GRAS § 184.1461 Manganese sulfate. (a) Manganese sulfate (MnSO4·H2O,...

  12. 21 CFR 184.1461 - Manganese sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... dioxide in sulfuric acid, and the roasting of pyrolusite (MnO2) ore with solid ferrous sulfate and coal... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Manganese sulfate. 184.1461 Section 184.1461 Food... Specific Substances Affirmed as GRAS § 184.1461 Manganese sulfate. (a) Manganese sulfate (MnSO4·H2O,...

  13. 21 CFR 184.1461 - Manganese sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... dioxide in sulfuric acid, and the roasting of pyrolusite (MnO2) ore with solid ferrous sulfate and coal... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Manganese sulfate. 184.1461 Section 184.1461 Food... Specific Substances Affirmed as GRAS § 184.1461 Manganese sulfate. (a) Manganese sulfate (MnSO4·H2O,...

  14. 21 CFR 184.1461 - Manganese sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... dioxide in sulfuric acid, and the roasting of pyrolusite (MnO2) ore with solid ferrous sulfate and coal... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Manganese sulfate. 184.1461 Section 184.1461 Food... Specific Substances Affirmed as GRAS § 184.1461 Manganese sulfate. (a) Manganese sulfate (MnSO4·H2O,...

  15. Negative impact of manganese on honeybee foraging

    PubMed Central

    Søvik, Eirik; Perry, Clint J.; LaMora, Angie; Barron, Andrew B.; Ben-Shahar, Yehuda

    2015-01-01

    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. 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

  17. 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.

  18. 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.

  19. Regulation of cellular manganese and manganese transport rates in the unicellular alga Chlamydomonas

    SciTech Connect

    Sunda, W.G.; Huntsman, S.A.

    1985-01-01

    The cellular accumulation and uptake kinetics of manganese by Chlamydomonas sp. were studied in model chelate buffer systems. Cellular manganese concentrations and uptake rates were related to the computed free manganese ion concentration and were independent of the total or chelated manganese concentration. Cellular manganese was constant at about 1 mmol liter/sup -1/ of cellular volume at free manganese ion concentrations of 10/sup -7/ /sup 6/-10/sup -6/ /sup 3/ mol liter/sup -1/ and decreased below this range. Manganese uptake rates followed saturation kinetics and V/sub max/, but not K/sub s/, varied with the free manganese ion concentration in the growth medium. V/sub max/ appeared to be under negative feedback control and increased with decreasing manganese ion concentration. Variations of up to 30-fold in this parameter seemed to be instrumental in limiting the variation in cellular manganese to a sixfold range despite a 1000-fold variation in free manganese ion concentration in the growth medium.

  20. Redox effects on release kinetics of arsenic, cadmium, cobalt, and vanadium in Wax Lake Deltaic freshwater marsh soils.

    PubMed

    Shaheen, Sabry M; Rinklebe, Jörg; Frohne, Tina; White, John R; DeLaune, Ron D

    2016-05-01

    The impact of redox potential (EH), pH, iron (Fe), manganese (Mn), chloride (Cl(-)), aliphatic and aromatic dissolved organic carbon (DOC), and sulfate ( [Formula: see text] ) on the release of dissolved arsenic (As), cadmium (Cd), cobalt (Co), and vanadium (V) were studied in Louisiana freshwater marsh Wax Lake Delta soil (Mississippi River) using an automated biogeochemical microcosm apparatus. The experiment was conducted from reducing (-60 mV) to stepwise oxidizing (+491 mV) conditions. The initial pH was 7.4 and decreased under reducing conditions to 4.9, and remained constant during the increase of EH. Concentrations of As (1.3-120.5 μg L(-1)), V (0.9-48.6 μg L(-1)), Fe, DOC, and the specific UV absorbance increased under reducing conditions and decreased with rising EH. Release of As and V appeared to be related to changes of EH/pH, co-precipitation with Fe oxides, and the release of dissolved aromatic carbon compounds. Concentrations of soluble Cd (4.8-11.2 μg L(-1)), Mn, [Formula: see text] , and Cl(-) increased under oxidizing conditions. Release of Co (166.6-258.2 μg L(-1)) was related to the chemistry of Fe, Mn and DOC. Phospholipid fatty acids analysis indicated the potential for the microbial community to be involved in biogeochemical processes such as the formation of sulfides, oxidation and reduction of compounds, and the bio-methylation of elements such as As. Overall, we measured a release of As and V under anoxic conditions, while oxic conditions favored the release of Cd. These results outline concern on the potential risk of mobilization of toxic elements in temporary waterlogged soils for agricultural purposes in deltaic ecosystems.

  1. 21 CFR 73.2775 - Manganese violet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2775 Manganese violet. (a) Identity. The color additive... less than 93 percent. (c) Uses and restrictions. Manganese violet is safe for use in coloring cosmetics generally, including cosmetics applied to the area of the eye, in amounts consistent with good...

  2. 21 CFR 73.2775 - Manganese violet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2775 Manganese violet. (a) Identity. The color additive... less than 93 percent. (c) Uses and restrictions. Manganese violet is safe for use in coloring cosmetics generally, including cosmetics applied to the area of the eye, in amounts consistent with good...

  3. 21 CFR 73.2775 - Manganese violet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2775 Manganese violet. (a) Identity. The color additive... less than 93 percent. (c) Uses and restrictions. Manganese violet is safe for use in coloring cosmetics generally, including cosmetics applied to the area of the eye, in amounts consistent with good...

  4. 21 CFR 73.2775 - Manganese violet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2775 Manganese violet. (a) Identity. The color additive... less than 93 percent. (c) Uses and restrictions. Manganese violet is safe for use in coloring cosmetics generally, including cosmetics applied to the area of the eye, in amounts consistent with good...

  5. Lithium intercalation properties in manganese-iron Prussian blue analogues

    NASA Astrophysics Data System (ADS)

    Matsuda, T.; Kurihara, Y.; Moritomo, Y.

    2013-04-01

    We investigated the electronic states and structural properties of LixMn[Fe(CN)6]0.83·3.5H2O, and LixMn[Fe(CN)6]0.87·2.6H2O, which have different amount of [Fe(CN)6] vacancies. X-ray absorption spectra near the Fe and Mn K-edges revealed that the Li intercalation/deintercalation process is two-electron reaction, i.e. MnII—NC—FeII, MnII—NC—FeIII, and MnIII—NC—FeIII. The crystal structure of LixMn[Fe(CN)6]0.83·3.5H2O remains cubic and single phase throughout the Li intercalation/deintercalation process. The crystal structure of LixMn[Fe(CN)6]0.87·2.6H2O is also cubic, while phase separation of Li+-rich phase and Li+-poor phase was observed during the MnII/MnIII reduction/oxidation process.

  6. Manganese and iron as oxygen carriers to anoxie estuarine sediment

    NASA Astrophysics Data System (ADS)

    Brayner, F. M. M.; Matvienko, B.

    2003-05-01

    We studied the concentration of a series of transition metals including Mn and Fe in an estuarine fishpond. The pond is situated at latitude 8°10'S and longitude 34°55'W, in the Capibaribe River estuary, within the Recife city boundaries, which is located in Pernambuco, a state of the Brazilian Northeast Pond area is 1.5 ha and it bas a 0.5 m depth. It is separated from the river by dikes. Water temperature at 28° C is stable throughout the year. Light breezes keep the water aerated, but intense ongoing decomposition makes the sediment anoxie. The area, originally of mangrove type, has been changed by antropic action on its fauna and vegetation. The study focuses on changes in behaviour of heavy metals. Samples of bottom sediments wore collected by Eckman dredge sediment sampler and total metal concentration was determined by the lithium borate fusion method. Water, recent sediment, and consolidated sediment were examined in this fishpond where Mn and Fe are brought in periodically by water and then gradually go into the sediment at respective rates of 10.52 and 1332 mg m^{-2}a^{-1}. Strong bioturbation re-suspends sediment while simultaneously re-dissolution of these ions is going on fhrough reduction in the anoxie sédiment. As soluble species these ions migrate from sediment to water and are there continually oxidized by dissolved oxygen, becoming insoluble. With their precipitation, chemically bound oxygen is carried down to the sediment, constituting a parallel channel of transport in addition to migration into the sediment bydiffusion of the oxygen dissolved in the water. The estimated flow rates are 3.25 and 76 mg O2 m^{-2}a^{-1} due to Mn and Fe respectively. The rates were established using natural silicon as a tracer.

  7. Interstellar iron and manganese - UV oscillator strengths and abundances

    NASA Technical Reports Server (NTRS)

    Lugger, P.; Barker, E.; York, D. G.; Oegerle, W.

    1982-01-01

    Observations of 16 UV resonance lines of Fe II and six of Mn II in five stars are used to derive new f-values for the lines of these species at wavelengths lower than 1300 A. Values of forbidden lines Fe/H and Mn/H are derived. These new values are used to reassess mean depletions and range of variations in depletions for several lines of sight. On an integrated line-of-sight basis, depletions of Fe and Mn show larger variations than P, Cl, or Zn. The mean local depletion forbidden line Fe/H is 1.65, in interstellar gas. One Fe II line, 2366.864 A, has never been detected. Its f-value is shown to be much lower than previously thought. This line is therefore not useful for interstellar studies at the present time. It is suggested that the true wavelength of 1142 A of Fe II, from UV multiplet 10, is 1142.285 A.

  8. Manganese inhibition of microbial iron reduction in anaerobic sediments

    USGS Publications Warehouse

    Lovley, D.R.; Phillips, E.J.P.

    1988-01-01

    Potential mechanisms for the lack of Fe(II) accumulation in Mn(IV)-containing anaerobic sediments were investigated. The addition of Mn(IV) to sediments in which Fe(II) 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. Results demonstrate that preferential reduction of Mn(IV) by FE(III)-reducing bacteria cannot completely explain the lack of Fe(II) accumulation in anaerobic, Mn(IV)-containing sediments, and indicate that Mn(IV) oxidation of Fe(II) is the mechanism that ultimately prevents Fe(II) accumulation. -Authors

  9. RNASeq in C. elegans following manganese exposure

    PubMed Central

    Parmalee, Nancy L.; Maqbool, Shahina B.; Ye, Bin; Calder, Brent; Bowman, Aaron B.; Aschner, Michael

    2015-01-01

    Manganese is a metal that is required for optimal biological functioning of organisms. Absorption, cellular import and export, and excretion of manganese are all tightly regulated. While some genes involved in regulation, such as DMT-1 and ferroportin are known, it is presumed that many more are involved and as yet unknown. Excessive exposure to manganese, usually in industrial settings, such as mining or welding, can lead to neurotoxicity and a condition known as manganism that closely resembles Parkinson's disease. Elucidating transcriptional changes following manganese exposure could lead to the development of biomarkers for exposure. This unit presents a protocol for RNA sequencing in the worm Caenorhabditis elegans to assay for transcriptional changes following exposure to manganese. This protocol is adaptable to any environmental exposure in C. elegans. The protocol results in counts of gene transcripts in control versus exposed conditions, and a ranked list of differentially expressed genes for further study. PMID:26250396

  10. SINGLE CRYSTAL CADMIUM SULFIDE AND CADMIUM SELENIDE INSULATED-GATE FIELD-EFFECT TRIODES.

    DTIC Science & Technology

    Insulated-gate field-effect triodes were fabricated on single crystal cadmium sulfide and cadmium selenide . Both bulk crystals and platelets were...used for single crystal samples. Chromium and aluminum were found to make low impedance contacts to cadmium sulfide and cadmium selenide . The...polycrystalline cadmium sulfide and cadmium selenide IGFET’s. The characteristics of the fabricated devices were unstable with respect to time and temperature

  11. Hot coal gas desulfurization with manganese-based sorbents. Progress report, April 1, 1993--June 30, 1993

    SciTech Connect

    Hepworth, M.T.

    1993-07-15

    Focus of work is primarily in use of zinc ferrite and zinc titanate sorbents; however, an alternate sorbent, manganese dioxide-containing ore in mixture with alumina (75 wt % ore + 25 wt % Al{sub 2}O{sub 3}) may be a viable alternative to zinc-based sorbents. Manganese, for example, has a lower vapor pressure in the elemental state than zinc, hence it is not as likely to undergo depletion from the sorbent surface upon loading and regeneration cycles. Also manganese oxide is less readily reduced to the elemental state than iron hence the range of reduction potentials for oxygen is somewhat greater than for zinc ferrite. Thermodynamic analysis of the system shows it to be less amenable to sulfation than zinc ferrite. Potential also exists for utilization of manganese higher temperatures than zinc ferrite or titanate. This report gives the thermodynamic background for consideration of manganese-based sorbents as an alternative to zinc ferrite. To date the work is limited to thermogravimetric testing of four formulations of manganese-alumina sorbents to determine the optimum conditions of pelletization and enduration to produce reactive pellets.

  12. Iron persistence in a distal hydrothermal plume supported by dissolved-particulate exchange

    NASA Astrophysics Data System (ADS)

    Fitzsimmons, Jessica N.; John, Seth G.; Marsay, Christopher M.; Hoffman, Colleen L.; Nicholas, Sarah L.; Toner, Brandy M.; German, Christopher R.; Sherrell, Robert M.

    2017-02-01

    Hydrothermally sourced dissolved metals have been recorded in all ocean basins. In the oceans' largest known hydrothermal plume, extending westwards across the Pacific from the Southern East Pacific Rise, dissolved iron and manganese were shown by the GEOTRACES program to be transported halfway across the Pacific. Here, we report that particulate iron and manganese in the same plume also exceed background concentrations, even 4,000 km from the vent source. Both dissolved and particulate iron deepen by more than 350 m relative to 3He--a non-reactive tracer of hydrothermal input--crossing isopycnals. Manganese shows no similar descent. Individual plume particle analyses indicate that particulate iron occurs within low-density organic matrices, consistent with its slow sinking rate of 5-10 m yr-1. Chemical speciation and isotopic composition analyses reveal that particulate iron consists of Fe(III) oxyhydroxides, whereas dissolved iron consists of nanoparticulate Fe(III) oxyhydroxides and an organically complexed iron phase. The descent of plume-dissolved iron is best explained by reversible exchange onto slowly sinking particles, probably mediated by organic compounds binding iron. We suggest that in ocean regimes with high particulate iron loadings, dissolved iron fluxes may depend on the balance between stabilization in the dissolved phase and the reversibility of exchange onto sinking particles.

  13. Manganese and the Evolution of Photosynthesis.

    PubMed

    Fischer, Woodward W; Hemp, James; Johnson, Jena E

    2015-09-01

    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 Mn(2+), and ultimately water.

  14. Manganese and the Evolution of Photosynthesis

    NASA Astrophysics Data System (ADS)

    Fischer, Woodward W.; Hemp, James; Johnson, Jena E.

    2015-09-01

    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.

  15. Relationship between blood manganese and blood pressure in the Korean general population according to KNHANES 2008

    SciTech Connect

    Lee, Byung-Kook; Kim, Yangho

    2011-08-15

    Introduction: We present data on the association of manganese (Mn) level with hypertension in a representative sample of the adult Korean population who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) 2008. Methods: This study was based on the data obtained by KNHANES 2008, which was conducted for three years (2007-2009) using a rolling sampling design involving a complex, stratified, multistage, probability-cluster survey of a representative sample of the noninstitutionalized civilian population of South Korea. Results: Multiple regression analysis after controlling for covariates, including gender, age, regional area, education level, smoking, drinking status, hemoglobin, and serum creatinine, showed that the beta coefficients of log blood Mn were 3.514, 1.878, and 2.517 for diastolic blood pressure, and 3.593, 2.449, and 2.440 for systolic blood pressure in female, male, and all participants, respectively. Multiple regression analysis including three other blood metals, lead, mercury, and cadmium, revealed no significant effects of the three metals on blood pressure and showed no effect on the association between blood Mn and blood pressure. In addition, doubling the blood Mn increased the risk of hypertension 1.828, 1.573, and 1.567 fold in women, men, and all participants, respectively, after adjustment for covariates. The addition of blood lead, mercury, and cadmium as covariates did not affect the association between blood Mn and the prevalence of hypertension. Conclusion: Blood Mn level was associated with an increased risk of hypertension in a representative sample of the Korean adult population. - Highlights: {yields} We showed the association of manganese with hypertension in Korean population. {yields} This study was based on the data obtained by KNHANES 2008. {yields} Blood manganese level was associated with an increased risk of hypertension.

  16. Biogeochemical iron budgets of the Southern Ocean south of Australia: Decoupling of iron and nutrient cycles in the subantarctic zone by the summertime supply

    NASA Astrophysics Data System (ADS)

    Bowie, Andrew R.; Lannuzel, Delphine; Remenyi, Tomas A.; Wagener, Thibaut; Lam, Phoebe J.; Boyd, Philip W.; Guieu, CéCile; Townsend, Ashley T.; Trull, Thomas W.

    2009-12-01

    Climate change is projected to significantly alter the delivery (stratification, boundary currents, aridification of landmasses, glacial melt) of iron to the Southern Ocean. We report the most comprehensive suite of biogeochemical iron budgets to date for three contrasting sites in subantarctic and polar frontal waters south of Australia. Distinct regional environments were responsible for differences in the mode and strength of iron supply mechanisms, with higher iron stocks and fluxes observed in surface northern subantarctic waters, where atmospheric iron fluxes were greater. Subsurface waters southeast of Tasmania were also enriched with particulate iron, manganese and aluminum, indicative of a strong advective source from shelf sediments. Subantarctic phytoplankton blooms are thus driven by both seasonal iron supply from southward advection of subtropical waters and by wind-blown dust deposition, resulting in a strong decoupling of iron and nutrient cycles. We discuss the broader global significance our iron budgets for other ocean regions sensitive to climate-driven changes in iron supply.

  17. Mineral of the month: cadmium

    USGS Publications Warehouse

    Klimasauskas, Edward

    2005-01-01

    Cadmium, which was once used almost exclusively for pigments, now has many diverse applications. Cadmium’s low melting point, excellent electrical conductivity and resistance to corrosion make it valuable for many products including batteries, electroplated coatings, stabilizers for plastics, solar cells and nonferrous alloys. Today’s cadmium is primarily used in rechargeable batteries, accounting for about 78 percent of consumption in 2004. In 2000, an estimated 3.5 billion consumer batteries were sold in the United States, of which almost 10 percent were nickel-cadmium batteries.

  18. Silicate reduces cadmium uptake into cells of wheat.

    PubMed

    Greger, Maria; Kabir, Ahmad H; Landberg, Tommy; Maity, Pooja J; Lindberg, Sylvia

    2016-04-01

    Cadmium (Cd) is a health threat all over the world and high Cd content in wheat causes high Cd intake. Silicon (Si) decreases cadmium content in wheat grains and shoot. This work investigates whether and how silicate (Si) influences cadmium (Cd) uptake at the cellular level in wheat. Wheat seedlings were grown in the presence or absence of Si with or without Cd. Cadmium, Si, and iron (Fe) accumulation in roots and shoots was analysed. Leaf protoplasts from plants grown without Cd were investigated for Cd uptake in the presence or absence of Si using the fluorescent dye, Leadmium Green AM. Roots and shoots of plants subjected to all four treatments were investigated regarding the expression of genes involved in the Cd uptake across the plasma membrane (i.e. LCT1) and efflux of Cd into apoplasm or vacuole from the cytosol (i.e. HMA2). In addition, phytochelatin (PC) content and PC gene (PCS1) expression were analysed. Expression of iron and metal transporter genes (IRT1 and NRAMP1) were also analysed. Results indicated that Si reduced Cd accumulation in plants, especially in shoot. Si reduced Cd transport into the cytoplasm when Si was added both directly during the uptake measurements and to the growth medium. Silicate downregulated LCT1 and HMA2 and upregulated PCS1. In addition, Si enhanced PC formation when Cd was present. The IRT1 gene, which was downregulated by Cd was upregulated by Si in root and shoot facilitating Fe transport in wheat. NRAMP1 was similarly expressed, though the effect was limited to roots. This work is the first to show how Si influences Cd uptake on the cellular level.

  19. 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

  20. Cadmium effects on the thyroid gland.

    PubMed

    Jancic, Snezana A; Stosic, Bojan Z

    2014-01-01

    Cadmium has been listed as one of the 126 priority pollutants and a category I carcinogen. Carcinogenic effects of cadmium on the lungs, testicles, and prostate are widely recognized, but there has been insufficient research on the effect of cadmium on the thyroid gland. Cadmium has the affinity to accumulate not only in the liver, kidneys, and pancreas but also in the thyroid gland. It has been established that cadmium blood concentration correlates positively with its accumulation in the thyroid gland. Women of fertile age have higher cadmium blood and urine concentrations than men. In spite of its redox inertia, cadmium brings about oxidative stress and damage to the tissue by indirect mechanisms. Mitochondria are considered to be the main intracellular targets for cadmium. Colloid cystic goiter, adenomatoid follicular hyperplasia with low-grade dysplasia and thyroglobulin hypo- and asecretion, and parafollicular cell diffuse and nodular hyperplasia and hypertrophy are often found in chronic cadmium toxicity.

  1. Stimulation of Cadmium Uptake in Relation to the Cadmium Content of Plants 1

    PubMed Central

    Petit, Charles M.; Ringoet, Arthur; Myttenaere, Constant

    1978-01-01

    The time course of cadmium uptake by the roots of intact tomato plants (Lycopersicon esculentum Mill.) was measured in a nutrient solution with a micromolar cadmium concentration until all cadmium in the medium was exhausted. Exhaustion taking a few hours, cadmium was repeatedly added to the nutrient solution. The initial rate of cadmium uptake was computed for each cadmium addition. This rate sharply increased and ultimately leveled off, the maximum value being about three times higher than the value measured after the first cadmium addition. The stimulating effect of cadmium was associated with an inhibitory effect at higher levels of cadmium concentrations. An increase in the net cadmium influx with time could not be explained by the binding of heavy metal to a fixed number of organic compounds. Conceivably, the production of binding sites could be increased and cadmium might play a part in controlling the rate of sites production. PMID:16660557

  2. Manganese carbonate mineralization in the Molango district, Mexico

    USGS Publications Warehouse

    Okita, P.M.

    1992-01-01

    Mn carbonate mineralization is hosted by a finely laminated Upper Jurassic marine sedimentary sequence that forms the base of the Chipoco facies of the Taman Formation (Kimmeridgian). The carbonate ore bed consists of fine-grained rhodochrosite and dispersed organic matter, magnetite, and maghemite but generally only trace quantities of pyrite. Fine laminations and clotted textures suggest deposition in a restricted marine environment. Several geologic and geochemical processes resulted in the formation of Mn carbonate by the early diagenetic reduction of Mn oxides through the oxidation of organic matter and iron sulfide. The ultimate source of the manganese is uncertain but may have been fluvial-sediment loads or hydrothermal activity associated with the rifting of the Gulf of Mexico. -from Author

  3. Survey of mercury, cadmium and lead content of household batteries

    SciTech Connect

    Recknagel, Sebastian; Radant, Hendrik; Kohlmeyer, Regina

    2014-01-15

    Highlights: • A well selected sample of 146 batteries was analysed for its heavy metals content. • A comparison was made between heavy metals contents in batteries in 2006 and 2011. • No significant change after implementation of the new EU Batteries Directive. • Severe differences in heavy metal contents were found in different battery-types. - Abstract: The objective of this work was to provide updated information on the development of the potential impact of heavy metal containing batteries on municipal waste and battery recycling processes following transposition of the new EU Batteries Directive 2006/66/EC. A representative sample of 146 different types of commercially available dry and button cells as well as lithium-ion accumulators for mobile phones were analysed for their mercury (Hg)-, cadmium (Cd)- and lead (Pb)-contents. The methods used for preparing the cells and analysing the heavy metals Hg, Cd, and Pb were either developed during a former study or newly developed. Several batteries contained higher mass fractions of mercury or cadmium than the EU limits. Only half of the batteries with mercury and/or lead fractions above the marking thresholds were labelled. Alkaline–manganese mono-cells and Li-ion accumulators, on average, contained the lowest heavy metal concentrations, while zinc–carbon batteries, on average, contained the highest levels.

  4. Survey of mercury, cadmium and lead content of household batteries.

    PubMed

    Recknagel, Sebastian; Radant, Hendrik; Kohlmeyer, Regina

    2014-01-01

    The objective of this work was to provide updated information on the development of the potential impact of heavy metal containing batteries on municipal waste and battery recycling processes following transposition of the new EU Batteries Directive 2006/66/EC. A representative sample of 146 different types of commercially available dry and button cells as well as lithium-ion accumulators for mobile phones were analysed for their mercury (Hg)-, cadmium (Cd)- and lead (Pb)-contents. The methods used for preparing the cells and analysing the heavy metals Hg, Cd, and Pb were either developed during a former study or newly developed. Several batteries contained higher mass fractions of mercury or cadmium than the EU limits. Only half of the batteries with mercury and/or lead fractions above the marking thresholds were labelled. Alkaline-manganese mono-cells and Li-ion accumulators, on average, contained the lowest heavy metal concentrations, while zinc-carbon batteries, on average, contained the highest levels.

  5. Manganese

    MedlinePlus

    ... weeks can slightly reduce weight in overweight people. Wound healing. Early research suggests that applying a dressing containing ... to chronic wounds for 12 weeks may improve wound healing. Anemia. Other conditions. More evidence is needed to ...

  6. [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.

  7. Influence of welding fume on systemic iron status.

    PubMed

    Casjens, Swaantje; Henry, Jana; Rihs, Hans-Peter; Lehnert, Martin; Raulf-Heimsoth, Monika; Welge, Peter; Lotz, Anne; Gelder, Rainer Van; Hahn, Jens-Uwe; Stiegler, Hugo; Eisele, Lewin; Weiss, Tobias; Hartwig, Andrea; Brüning, Thomas; Pesch, Beate

    2014-11-01

    Iron is the major metal found in welding fumes, and although it is an essential trace element, its overload causes toxicity due to Fenton reactions. To avoid oxidative damage, excess iron is bound to ferritin, and as a result, serum ferritin (SF) is a recognized biomarker for iron stores, with high concentrations linked to inflammation and potentially also cancer. However, little is known about iron overload in welders. Within this study, we assessed the iron status and quantitative associations between airborne iron, body iron stores, and iron homeostasis in 192 welders not wearing dust masks. Welders were equipped with personal samplers in order to determine the levels of respirable iron in the breathing zone during a working shift. SF, prohepcidin and other markers of iron status were determined in blood samples collected after shift. The impact of iron exposure and other factors on SF and prohepcidin were estimated using multiple regression models. Our results indicate that respirable iron is a significant predictor of SF and prohepcidin. Concentrations of SF varied according to the welding technique and respiratory protection used, with a median of 103 μg l(-1) in tungsten inert gas welders, 125 μg l(-1) in those wearing air-purifying respirators, and 161 μg l(-1) in other welders. Compared to welders with low iron stores (SF < 25 μg l(-1)), those with excess body iron (SF ≥ 400 μg l(-1)) worked under a higher median concentration of airborne iron (60 μg m(-3) versus 148 μg m(-3)). Even though air concentrations of respirable iron and manganese were highly correlated, and low iron stores have been reported to increase manganese uptake in the gastrointestinal tract, no correlation was seen between SF and manganese in blood. In conclusion, monitoring SF may be a reasonable method for health surveillance of welders. Respiratory protection with air-purifying respirators can decrease iron exposure and avoid chronically higher SF in welders working with

  8. The Structural Basis for the Metal Selective Activation of the Manganese Transport Regulator of Bacillus subtilis†,§

    PubMed Central

    Kliegman, Joseph I.; Griner, Sarah L.; Helmann, John D.; Brennan, Richard G.; Glasfeld, Arthur

    2008-01-01

    The manganese transport regulator (MntR) of Bacillus subtilis is activated by Mn2+ to repress transcription of genes encoding transporters involved in the uptake of manganese. MntR is also strongly activated by cadmium, both in vivo and in vitro, but it is poorly activated by other metal cations, including calcium and zinc. The previously published MntR•Mn2+ structure revealed a binuclear complex of manganese ions with a metal-metal separation of 3.3 Å (herein designated the AB conformer). Analysis of four additional crystal forms of MntR•Mn2+ reveals that the AB conformer is only observed in monoclinic crystals at 100 K, suggesting that this conformation may be stabilized by crystal packing forces. In contrast, monoclinic crystals analyzed at room temperature (at either pH 6.5 or 8.5), and a second hexagonal crystal form (analyzed at 100 K), all reveal the shift of one manganese ion by 2.5 Å thereby leading to a newly identified conformation (the AC conformer) with an internuclear distance of 4.4 Å. Significantly, the cadmium and calcium complexes of MntR also contain binuclear complexes with a 4.4 Å internuclear separation. In contrast, the zinc complex of MntR contains only one metal ion per subunit, in the A site. Isothermal titration calorimetry confirms the stoichiometry of Mn2+, Cd2+ and Zn2+ binding to MntR. We propose that the specificity of MntR activation is tied to productive binding of metal ions at two sites; the A site appears to act as a selectivity filter, determining whether the B or C site will be occupied and thereby fully activate MntR. PMID:16533030

  9. Cadmium accumulation and depuration in Anodonta anatina exposed to cadmium chloride or cadmium-EDTA complex

    SciTech Connect

    Holwerda, D.A.; Hemelraad, J.; Veenhof, P.R.; Zandee, D.I.

    1988-03-01

    The authors have previously reported on the uptake and distribution of cadmium in unionids, experimentally exposed to cadmium chloride. The purpose of the present investigation was to study the effect of metal chelation on cadmium kinetics, including metal elimination in the post-exposure phase. Generally, chelation of ionic metal by natural substances like humic acids or by synthetic compounds like EDTA decreases its environmental toxicity through a diminished rate of uptake, as compared with the free ion. The influences of metal chelation on bioconcentration and on toxicity do not always run parallel. To their knowledge, there are no data on the effect of chelation on metal kinetics in freshwater clams. Data on rates of cadmium elimination from aquatic invertebrates are highly divergent, but Cd excretion is invariably found to be smaller than uptake.

  10. Neurotoxicity of manganese oxide nanomaterials

    NASA Astrophysics Data System (ADS)

    Stefanescu, Diana M.; Khoshnan, Ali; Patterson, Paul H.; Hering, Janet G.

    2009-11-01

    Manganese (Mn) toxicity in humans has been observed as manganism, a disease that resembles Parkinson's disease. The mechanism of Mn toxicity and the chemical forms that may be responsible for its neurotoxicity are not well understood. We examined the toxicity of Mn oxide nanomaterials in a neuronal precursor cell model, using the MTS assay to evaluate mitochondrial function in living cells and the LDH assay to quantify the release of the enzyme lactate dehydrogenase as a result of damage to the cell membrane. Both assays show that the toxicity of Mn is dependent on the type of Mn oxide nanomaterial and its concentration as well as on the state of cell differentiation. Following exposure to Mn oxide nanomaterials, reactive oxygen species (ROS) are generated, and flow cytometry experiments suggest that cell death occurred through apoptosis. During exposure to Mn oxide nanomaterials, increased levels of the transcription factor NF-κB (which mediates the cellular inflammatory response) were observed.

  11. Manganese-containing ionic liquids: synthesis, crystal structures and electrodeposition of manganese films and nanoparticles.

    PubMed

    Sniekers, Jeroen; Malaquias, João C; Van Meervelt, Luc; Fransaer, Jan; Binnemans, Koen

    2017-02-21

    Manganese(ii)-containing ionic liquids were synthesized, in which the manganese atoms are coordinated by glymes (diglyme, triglyme, tetraglyme), pyridine-N-oxide, dimethylsulfoxide or N-alkylimidazoles (N-methylimidazole, N-butylimidazole and N-hexylimidazole). As anion, bis(trifluoromethanesulfonyl)imide (bistriflimide, Tf2N(-)), trifluoromethanesulfonate (triflate, OTf(-)) or methanesulfonate (mesylate, OMs(-)) were used. The compounds were characterized by CHN analysis, FTIR, DSC and single-crystal X-ray diffraction measurements. All manganese atoms were six-coordinate. It was found that the glyme-type ligands were replaced by atmospheric water upon leaving the crystals open to the air for several days. The crystal structures of seven compounds were described in detail and the compounds with the lowest melting temperatures were tested as electrolytes for the electrodeposition of manganese (thin) films. An irreversible reduction wave from Mn(ii) to Mn(0) and granular manganese deposits were observed for all compounds, except for liquid manganese salts with N-alkylimidazole ligands and bistriflimide anions, where the electrochemical formation of manganese nanoparticles was observed instead of the deposition of a manganese layer. However, for compounds with the same cation but with a triflate or methanesulfonate anion, manganese metal deposits were obtained, indicating that the nature of the anion has an important effect on the electrochemical properties of liquid metal salts.

  12. Development of a hydrometallurgical route for the recovery of zinc and manganese from spent alkaline batteries

    NASA Astrophysics Data System (ADS)

    Veloso, Leonardo Roger Silva; Rodrigues, Luiz Eduardo Oliveira Carmo; Ferreira, Daniel Alvarenga; Magalhães, Fernando Silva; Mansur, Marcelo Borges

    A hydrometallurgical route is proposed in this paper for the selective separation of zinc and manganese from spent alkaline batteries. The recycling route comprises the following steps: (1) batteries dismantling to separate the spent batteries dust from other components (iron scraps, plastic and paper), (2) grinding of the batteries dust to produce a black homogeneous powder, (3) leaching of the powder in two sequential steps, "neutral leaching with water" to separate potassium and produce a KOH solution, followed by an "acidic leaching with sulphuric acid" to remove zinc and manganese from the powder, and (4) selective precipitation of zinc and manganese using the KOH solution (pH around 11) produced in the neutral leaching step. For the acidic leaching step, two alternative routes have been investigated (selective leaching of zinc and total leaching) with regard to the following operational variables: temperature, time, sulphuric acid concentration, hydrogen peroxide concentration and solid/liquid ratio. The results obtained in this study have shown that the proposed route is technically simple, versatile and provides efficient separation of zinc and manganese.

  13. The detection of magnetotactic bacteria in deep sea sediments from the east Pacific Manganese Nodule Province.

    PubMed

    Dong, Yi; Li, Jinhua; Zhang, Wuchang; Zhang, Wenyan; Zhao, Yuan; Xiao, Tian; Wu, Long-Fei; Pan, Hongmiao

    2016-04-01

    Magnetotactic bacteria (MTB) are distributed ubiquitously in sediments from coastal environments to the deep sea. The Pacific Manganese Nodule Province contains numerous polymetallic nodules mainly composed of manganese, iron, cobalt, copper and nickel. In the present study we used Illumina MiSeq sequencing technology to assess the communities of putative MTB in deep sea surface sediments at nine stations in the east Pacific Manganese Nodule Province. A total of 402 sequence reads from MTB were classified into six operational taxonomic units (OTUs). Among these, OTU113 and OTU759 were affiliated with the genus Magnetospira, OTU2224 and OTU2794 were affiliated with the genus Magnetococcus and Magnetovibrio, respectively, OTU3017 had no known genus affiliation, and OTU2556 was most similar to Candidatus Magnetananas. Interestingly, OTU759 was widely distributed, occurring at all study sites. Magnetism measurements revealed that all sediments were dominated by low coercivity, non-interacting single domain magnetic minerals. Transmission electron microscopy confirmed that the magnetic minerals were magnetosomes. Our data suggest that diverse putative MTB are widely distributed in deep sea surface sediments from the east Pacific Manganese Nodule Province.

  14. 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...

  15. Dietary exposure to cadmium and health effects: impact of environmental changes.

    PubMed

    Piscator, M

    1985-11-01

    Cadmium exposure, metabolism, and effects are described especially in relation to dietary intakes. Data on dietary intakes in several countries have been complied from studies using the duplicate diet method or fecal analysis. These two methods seem to give more accurate data than estimates based on cadmium concentrations in food classes and food consumption (composite method). The present data on absorption and retention of ingested cadmium i