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Sample records for ferrous heme-no oxidation

  1. Potential for microbial oxidation of ferrous iron in basaltic glass.

    Science.gov (United States)

    Xiong, Mai Yia; Shelobolina, Evgenya S; Roden, Eric E

    2015-05-01

    Basaltic glass (BG) is an amorphous ferrous iron [Fe(II)]-containing material present in basaltic rocks, which are abundant on rocky planets such as Earth and Mars. Previous research has suggested that Fe(II) in BG can serve as an energy source for chemolithotrophic microbial metabolism, which has important ramifications for potential past and present microbial life on Mars. However, to date there has been no direct demonstration of microbially catalyzed oxidation of Fe(II) in BG. In this study, three different culture systems were used to investigate the potential for microbial oxidation of Fe(II) in BG, including (1) the chemolithoautotrophic Fe(II)-oxidizing, nitrate-reducing "Straub culture"; (2) the mixotrophic Fe(II)-oxidizing, nitrate-reducing organism Desulfitobacterium frappieri strain G2; and (3) indigenous microorganisms from a streambed Fe seep in Wisconsin. The BG employed consisted of clay and silt-sized particles of freshly quenched lava from the TEB flow in Kilauea, Hawaii. Soluble Fe(II) or chemically reduced NAu-2 smectite (RS) were employed as positive controls to verify Fe(II) oxidation activity in the culture systems. All three systems demonstrated oxidation of soluble Fe(II) and/or structural Fe(II) in RS, whereas no oxidation of Fe(II) in BG material was observed. The inability of the Straub culture to oxidize Fe(II) in BG was particularly surprising, as this culture can oxidize other insoluble Fe(II)-bearing minerals such as biotite, magnetite, and siderite. Although the reason for the resistance of the BG toward enzymatic oxidation remains unknown, it seems possible that the absence of distinct crystal faces or edge sites in the amorphous glass renders the material resistant to such attack. These findings have implications with regard to the idea that Fe(II)-Si-rich phases in basalt rocks could provide a basis for chemolithotrophic microbial life on Mars, specifically in neutral-pH environments where acid-promoted mineral dissolution and

  2. Absorption of nitric oxide into aqueous solutions of ferrous chelates accompanied by instantaneous reaction

    NARCIS (Netherlands)

    Demmink, J.F; vanGils, I.C.F.; Beenackers, A.A C M

    1997-01-01

    The absorption of nitric oxide (NO) into aqueous solutions of ferrous chelates of nitrilotriacetic acid (NTA), ethylene diaminetetraacetic acid (EDTA), hydroxyethylenediaminetriacetic acid (HEDTA), and diethylenetriaminepentaacetic acid (DTPA) was studied in a stirred cell reactor. Experimental

  3. Effect of calcium oxide on the efficiency of ferrous ion oxidation and total iron precipitation during ferrous ion oxidation in simulated acid mine drainage treatment with inoculation of Acidithiobacillus ferrooxidans.

    Science.gov (United States)

    Liu, Fenwu; Zhou, Jun; Jin, Tongjun; Zhang, Shasha; Liu, Lanlan

    2016-01-01

    Calcium oxide was added into ferrous ion oxidation system in the presence of Acidithiobacillus ferrooxidans at concentrations of 0-4.00 g/L. The pH, ferrous ion oxidation efficiency, total iron precipitation efficiency, and phase of the solid minerals harvested from different treatments were investigated during the ferrous ion oxidation process. In control check (CK) system, pH of the solution decreased from 2.81 to 2.25 when ferrous ions achieved complete oxidation after 72 h of Acidithiobacillus ferrooxidans incubation without the addition of calcium oxide, and total iron precipitation efficiency reached 20.2%. Efficiency of ferrous ion oxidation and total iron precipitation was significantly improved when the amount of calcium oxide added was ≤1.33 g/L, and the minerals harvested from systems were mainly a mixture of jarosite and schwertmannite. For example, the ferrous ion oxidation efficiency reached 100% at 60 h and total iron precipitation efficiency was increased to 32.1% at 72 h when 1.33 g/L of calcium oxide was added. However, ferrous ion oxidation and total iron precipitation for jarosite and schwertmannite formation were inhibited if the amount of calcium oxide added was above 2.67 g/L, and large amounts of calcium sulfate dihydrate were generated in systems.

  4. Bioleaching of heavy metals from sewage sludge by indigenous iron-oxidizing microorganisms using ammonium ferrous sulfate and ferrous sulfate as energy sources: a comparative study.

    Science.gov (United States)

    Pathak, Ashish; Dastidar, M G; Sreekrishnan, T R

    2009-11-15

    The potential of indigenous iron-oxidizing microorganisms enriched at initial neutral pH of the sewage sludge for bioleaching of heavy metals was investigated at initial neutral pH of the sludge using ammonium ferrous sulfate (FAS) and ferrous sulfate (FS) as an energy sources in two different sets of experiments. After 16 days of bioleaching, 56% Cu, 48% Ni, 68% Zn and 42% C were removed from the sludge using ammonium ferrous sulfate as an energy source. On the other hand, 64% Cu, 58% Ni, 76% Zn and 52% Cr were removed using ferrous sulfate. Further, 32% nitrogen and 24% phosphorus were leached from the sludge using ferrous sulfate, whereas only 22% nitrogen and 17% phosphorus were removed using ammonium ferrous sulfate. The BCR sequential extraction study on speciation of metals showed that using ammonium ferrous sulfate and ferrous sulfate, all the metals remained in bioleached sludge as stable form (F4 fraction). The results of the present study indicate that the bioleached sludge would be safer for land application. Also, the fertilizing property was largely conserved in the bioleached sludge using both the substrates.

  5. Oxidative Alteration of Ferrous Smectites and Implications for the Redox Evolution of Early Mars

    Science.gov (United States)

    Chemtob, Steven M.; Nickerson, Ryan D.; Morris, Richard V.; Agresti, David G.; Catalano, Jeffrey G.

    2017-12-01

    Surface conditions on early Mars were likely anoxic, similar to early Earth, but the timing of the evolution to oxic conditions characteristic of contemporary Mars is unresolved. Ferrous trioctahedral smectites are the thermodynamically predicted products of anoxic basalt weathering, but orbital analyses of Noachian-aged terrains find primarily Fe3+-bearing clay minerals. Rover-based detection of Fe2+-bearing trioctahedral smectites at Gale Crater suggests that ferrous smectites are the unoxidized progenitors of orbitally detected ferric smectites. To assess this pathway, we conducted ambient-temperature oxidative alteration experiments on four synthetic ferrous smectites having molar Fe/(Mg + Fe) from 1.00 to 0.33. Smectite suspension in air-saturated solutions produced incomplete oxidation (24-38% Fe3+/ΣFe). Additional smectite oxidation occurred upon reexposure to air-saturated solutions after anoxic hydrothermal recrystallization, which accelerated cation and charge redistribution in the octahedral sheet. Oxidation was accompanied by contraction of the octahedral sheet (d(060) decreased from 1.53-1.56 Å to 1.52 Å), consistent with a shift toward dioctahedral structure. Ferrous smectite oxidation by aqueous hydrogen peroxide solutions resulted in nearly complete Fe2+ oxidation but also led to partial Fe3+ ejection from the structure, producing nanoparticulate hematite. Reflectance spectra of oxidized smectites were characterized by (Fe3+,Mg)2-OH bands at 2.28-2.30 μm, consistent with oxidative formation of dioctahedral nontronite. Accordingly, ferrous smectites are plausible precursors to observed ferric smectites on Mars, and their presence in late-Noachian sedimentary units suggests that anoxic conditions may have persisted on Mars beyond the Noachian.

  6. Degradation of toluene, ethylbenzene, and xylene using heat and chelated-ferrous iron activated persulfate oxidation

    Science.gov (United States)

    Mondal, P.; Sleep, B.

    2014-12-01

    Toluene, ethylbenze, and xylene (TEX) are common contaminants in the subsurface. Activated persulfate has shown promise for degrading a wide variety of organic compounds. However, studies of persulfate application for in situ degradation of TEX and effects on the subsequent bioremediation are limited. In this work, degradation studies of TEX in aqueous media and soil are being conducted using heat activated and chelated-ferrous iron activated persulfate oxidation in batch and flow-through column experiments. In the batch experiments, sodium persulfate is being used at different concentrations to provide an initial persulfate to TEX molar ratios between 10:1 and 100:1. Sodium persulfate solutions are being activated at 20, 37, 60, and 80 oC temperatures for the heat activated oxidation. For the chelated-ferrous iron activated oxidation, ferrous iron and citric acid, both are being used at concentration of 5 mM. In the experiments with soil slurry, a soil to water ratio of 1 to 5 is being used. Flow through water saturated column experiments are being conducted with glass columns (45 cm in length and 4 cm in diameter) uniformly packed with soils, and equilibrated with water containing TEX at the target concentrations. Both the heat activation and chelated-ferrous iron activation of persulfate are being employed in the column experiments. Future experiments are planned to determine the suitability of persulfate oxidation of TEX on the subsequent biodegradation using batch microcosms containing TEX degrading microbial cultures. In these experiments, the microbial biomass will be monitored using total phospholipids, and the microbial community will be determined using quantitative real-time polymerase chain reaction (qPCR) on the extracted DNA. This study is expected to provide suitable operating conditions for in situ chemical oxidation of TEX with activated persulfate followed by bioremediation.

  7. A novel reverse osmosis membrane by ferrous sulfate assisted controlled oxidation of polyamide layer

    Science.gov (United States)

    Raval, Hiren D.; Raviya, Mayur R.; Gauswami, Maulik V.

    2017-11-01

    With growing desalination capacity, it is very important to evaluate the performance of thin film composite reverse osmosis (TFC RO) membrane in terms of energy consumption for desalination. There is a trade-off between salt rejection and water-flux of TFC RO membrane. This article presents a novel approach of analyzing the effect of mixture of an oxidizing agent sodium hypochlorite and a reducing agent ferrous sulfate on virgin TFC RO membrane. Experiments were carried out by varying the concentrations of both sodium hypochlorite and ferrous sulfate. The negative charge was induced on the membrane due to the treatment of combination of sodium hypochlorite and ferrous sulfate, thereby resulting in higher rejection of negative ions due to repulsive force. Membrane treated with 1000 mg l-1 sodium hypochlorite and 2000 mg l-1 ferrous sulfate showed the best salt rejection i.e. 96.23%. The characterization was carried out to understand the charge on the membrane surface by Zeta potential, morphology of membrane surface by scanning electron microscope (SEM), surface roughness features by atomic force microscope (AFM) and chemical structural changes by nuclear magnetic resonance (NMR) analysis.

  8. Ferrous-activated persulfate oxidation of arsenic(III) and diuron in aquatic system

    International Nuclear Information System (INIS)

    Zhou, Lei; Zheng, Wei; Ji, Yuefei; Zhang, Jinfeng; Zeng, Chao; Zhang, Ya; Wang, Qi; Yang, Xi

    2013-01-01

    Highlights: • Effective oxidation of As(III)/diuron is achieved by Fe(II)-activated persulfate. • Hydroxyl and sulfate radical play important roles in As(III) and diuron oxidation. • CA and Na 2 S 2 O 3 are efficient and environmental friendly chelating agents. • DFT calculation is found to be useful for degradation products prediction. -- Abstract: In situ chemical oxidation (ISCO) can be an effective technology for the remediation of soil and groundwater polluted by organic and inorganic contaminants. This study investigated the oxidation of arsenic(III) (As(III)) and diuron using ferrous activated persulfate-based ISCO. The results indicated that Fe(II)/persulfate oxidation could be an effective method to oxidize As(III) and diuron. Effects of pH, S 2 O 8 2− and Fe(II) amounts on the destruction of As(III) and diuron were examined in batch experiments. Acidic conditions favored the removal of As(III) and diuron. Four chelating agents, citric acid (CA), Na 2 S 2 O 3 , diethylene triamine pentaacetic acid (DTPA) and ethylene diamine tetraacetic acid disodium (EDTA-Na 2 ) were used in attempt to maintain the quantity of ferrous ion in solution. In our experiments, CA and Na 2 S 2 O 3 were found to be more effective than DTPA and EDTA-Na 2 . Our results also revealed a widely practical prospect of inorganic chelating agent Na 2 S 2 O 3 . Hydroxyl and sulfate radical were determined to play key roles in the oxidation process by using ethanol and tertiary butanol as molecular probes. Oxidation of As(III) yielded As(V) via the electron-transfer reaction. In the oxidation process of diuron, a stepwise nucleophilic substitution of chlorine by hydroxyl and a stepwise oxidation process of the methyl on the dimethylurea group by hydroxyl and sulfate radical were proposed

  9. Ferrous-activated persulfate oxidation of arsenic(III) and diuron in aquatic system.

    Science.gov (United States)

    Zhou, Lei; Zheng, Wei; Ji, Yuefei; Zhang, Jinfeng; Zeng, Chao; Zhang, Ya; Wang, Qi; Yang, Xi

    2013-12-15

    In situ chemical oxidation (ISCO) can be an effective technology for the remediation of soil and groundwater polluted by organic and inorganic contaminants. This study investigated the oxidation of arsenic(III) (As(III)) and diuron using ferrous activated persulfate-based ISCO. The results indicated that Fe(II)/persulfate oxidation could be an effective method to oxidize As(III) and diuron. Effects of pH, S2O8(2-) and Fe(II) amounts on the destruction of As(III) and diuron were examined in batch experiments. Acidic conditions favored the removal of As(III) and diuron. Four chelating agents, citric acid (CA), Na2S2O3, diethylene triamine pentaacetic acid (DTPA) and ethylene diamine tetraacetic acid disodium (EDTA-Na2) were used in attempt to maintain the quantity of ferrous ion in solution. In our experiments, CA and Na2S2O3 were found to be more effective than DTPA and EDTA-Na2. Our results also revealed a widely practical prospect of inorganic chelating agent Na2S2O3. Hydroxyl and sulfate radical were determined to play key roles in the oxidation process by using ethanol and tertiary butanol as molecular probes. Oxidation of As(III) yielded As(V) via the electron-transfer reaction. In the oxidation process of diuron, a stepwise nucleophilic substitution of chlorine by hydroxyl and a stepwise oxidation process of the methyl on the dimethylurea group by hydroxyl and sulfate radical were proposed. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Ferrous iron oxidation by sulfur-oxidizing Acidithiobacillus ferrooxidans and analysis of the process at the levels of transcription and protein synthesis.

    Science.gov (United States)

    Kucera, Jiri; Bouchal, Pavel; Lochman, Jan; Potesil, David; Janiczek, Oldrich; Zdrahal, Zbynek; Mandl, Martin

    2013-04-01

    In contrast to iron-oxidizing Acidithiobacillus ferrooxidans, A. ferrooxidans from a stationary phase elemental sulfur-oxidizing culture exhibited a lag phase in pyrite oxidation, which is similar to its behaviour during ferrous iron oxidation. The ability of elemental sulfur-oxidizing A. ferrooxidans to immediately oxidize ferrous iron or pyrite without a lag phase was only observed in bacteria obtained from growing cultures with elemental sulfur. However, these cultures that shifted to ferrous iron oxidation showed a low rate of ferrous iron oxidation while no growth was observed. Two-dimensional gel electrophoresis was used for a quantitative proteomic analysis of the adaptation process when bacteria were switched from elemental sulfur to ferrous iron. A comparison of total cell lysates revealed 39 proteins whose increase or decrease in abundance was related to this phenotypic switching. However, only a few proteins were closely related to iron and sulfur metabolism. Reverse-transcription quantitative PCR was used to further characterize the bacterial adaptation process. The expression profiles of selected genes primarily involved in the ferrous iron oxidation indicated that phenotypic switching is a complex process that includes the activation of genes encoding a membrane protein, maturation proteins, electron transport proteins and their regulators.

  11. Reaction mechanisms and evaluation of effective process operation for catalytic oxidation and coagulation by ferrous solution and hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.H.; Moon, H.J.; Kim, Y.M. [Dept. of Environmental Engineering, Sangmyung Univ., Cheonan (Korea); Bae, W.K. [Dept. of Civil and Environmental Engineering, Hanyang Univ., Ansan, Kyounggi (Korea)

    2003-07-01

    This research was carried out to evaluate the removal efficiencies of COD{sub cr} and colour for the dyeing wastewater by ferrous solution and the different dosage of H{sub 2}O{sub 2} in Fenton process. In the case of H{sub 2}O{sub 2} divided dosage, 7:3 was more effective than 3:7 to remove COD{sub cr} and colour. The results showed that COD was mainly removed by Fenton coagulation, where the ferric ions are formed in the initial step of Fenton reaction. On the other hand colour was removed by Fenton oxidation rather than Fenton coagulation. This paper also aims at pursuing to investigate the effective removal mechanisms using ferrous ion coagulation, ferric ion coagulation and Fenton oxidation process. The removal mechanism of COD{sub cr} and colour was mainly coagulation by ferrous ion, ferric ion and Fenton oxidation. The removal efficiencies were dependent on the ferric ion amount at the beginning of the reaction. However the final removal efficiency of COD and colour was in the order of Fenton oxidation, ferric ion coagulation and ferrous ion coagulation. The reason of the highest removal efficiency by Fenton oxidation can be explained by the chain reactions with ferrous solution, ferric ion and hydrogen peroxide. (orig.)

  12. Resistance to High-Temperature Oxidation and Wear of Various Ferrous Alloys Used in Rolling Mills

    Science.gov (United States)

    Delaunois, Fabienne; Stanciu, Victor Ioan; Sinnaeve, Mario

    2018-01-01

    Various materials are commonly used to manufacture work rolls for hot rolling mills, such as ICDP (Indefinite Chill Double Pour) cast irons, high-chromium white cast irons, and high speed steels (HSS). Various chemical compositions and microstructures are studied in order to optimize the in-use behavior of those grades of rolls. In this paper, six grades of ferrous alloys (an ICDP cast iron; an ICDP cast iron enriched in vanadium, niobium, and molybdenum; a HSS; a graphitic HSS; a high-chromium white cast iron (Hi-Cr); and a niobium-molybdenum-doped high-chromium white cast iron) were investigated. High-temperature oxidation tests with gravimetric means at 575 °C in water vapor atmosphere and sliding wear tests were carried out. The oxidation kinetics was followed during oxidation test. The microstructure was observed by optical and scanning electron microscopies. The oxides formed on the surface of the samples were analyzed by XRD and EDS. The thickness of the oxide scales and the mass gain were measured after oxidation test. The results showed that the behavior of all the grades differed. The oxide scale of HSS and HSS-G grades was fine and their friction coefficient was low. The weight gain after oxidation test of HSS was high. Hi-Cr and M-Hi-Cr grades presented highly porous oxide layer and an important increase of the friction coefficient during wear test. ICDP and M-ICDP had intermediate behavior.

  13. Resistance to High-Temperature Oxidation and Wear of Various Ferrous Alloys Used in Rolling Mills

    Science.gov (United States)

    Delaunois, Fabienne; Stanciu, Victor Ioan; Sinnaeve, Mario

    2018-03-01

    Various materials are commonly used to manufacture work rolls for hot rolling mills, such as ICDP (Indefinite Chill Double Pour) cast irons, high-chromium white cast irons, and high speed steels (HSS). Various chemical compositions and microstructures are studied in order to optimize the in-use behavior of those grades of rolls. In this paper, six grades of ferrous alloys (an ICDP cast iron; an ICDP cast iron enriched in vanadium, niobium, and molybdenum; a HSS; a graphitic HSS; a high-chromium white cast iron (Hi-Cr); and a niobium-molybdenum-doped high-chromium white cast iron) were investigated. High-temperature oxidation tests with gravimetric means at 575 °C in water vapor atmosphere and sliding wear tests were carried out. The oxidation kinetics was followed during oxidation test. The microstructure was observed by optical and scanning electron microscopies. The oxides formed on the surface of the samples were analyzed by XRD and EDS. The thickness of the oxide scales and the mass gain were measured after oxidation test. The results showed that the behavior of all the grades differed. The oxide scale of HSS and HSS-G grades was fine and their friction coefficient was low. The weight gain after oxidation test of HSS was high. Hi-Cr and M-Hi-Cr grades presented highly porous oxide layer and an important increase of the friction coefficient during wear test. ICDP and M-ICDP had intermediate behavior.

  14. Inhibition of bacterial oxidation of ferrous iron by lead nitrate in sulfate-rich systems

    Science.gov (United States)

    Wang, Hongmei; Gong, Linfeng; Cravotta,, Charles A.; Yang, Xiaofen; Tuovinen, Olli H.; Dong, Hailiang; Fu, Xiang

    2013-01-01

    Inhibition of bacterial oxidation of ferrous iron (Fe(II)) by Pb(NO3)2 was investigated with a mixed culture of Acidithiobacillus ferrooxidans. The culture was incubated at 30 °C in ferrous-sulfate medium amended with 0–24.2 mM Pb(II) added as Pb(NO3)2. Anglesite (PbSO4) precipitated immediately upon Pb addition and was the only solid phase detected in the abiotic controls. Both anglesite and jarosite (KFe3(SO4)2(OH)6) were detected in inoculated cultures. Precipitation of anglesite maintained dissolved Pb concentrations at 16.9–17.6 μM regardless of the concentrations of Pb(NO3)2 added. Fe(II) oxidation was suppressed by 24.2 mM Pb(NO3)2 addition even when anglesite was removed before inoculation. Experiments with 0–48 mM KNO3 demonstrated that bacterial Fe(II) oxidation decreased as nitrate concentration increased. Therefore, inhibition of Fe(II) oxidation at 24.2 mM Pb(NO3)2 addition resulted from nitrate toxicity instead of Pb addition. Geochemical modeling that considered the initial precipitation of anglesite to equilibrium followed by progressive oxidation of Fe(II) and the precipitation of jarosite and an amorphous iron hydroxide phase, without allowing plumbojarosite to precipitate were consistent with the experimental time-series data on Fe(II) oxidation under biotic conditions. Anglesite precipitation in mine tailings and other sulfate-rich systems maintains dissolved Pb concentrations below the toxicity threshold of A. ferrooxidans.

  15. The Effect of Ferrous Nano-oxide Particles on Physiological Traits and Nutritional Compounds of Soybean ( Glycine max L.) Seed.

    Science.gov (United States)

    Sheykhbaglou, Roghayyeh; Sedghi, Mohammad; Fathi-Achachlouie, Bahram

    2018-02-19

    Soybean (Glycine max L.) seed contains amounts of protein, lipid, carbohydrate and mineral elements, which protein and lipid have been known as a main part for soybean's trade value. In this study, in order to investigate the effect of ferrous nano-oxide particles on nutritional compounds of soybean seed, an experiment with 5 treatments and 3 replications was conducted as a randomized complete block design. Treatments were 5 concentrations of ferrous nano-oxide particles including 0, 0.25, 0.5, 0.75 and 1 g L-1 which were sprayed 3 times at 4 and 8 leaves stage and pod initiation. Lipid and protein contents, fatty acids profile, some of mineral elements such as Fe, Mg, Ca and P, chlorophyll a, b and total chlorophyll content were determined. Results showed that solution containing ferrous nano-oxide particles had significant effect on nutritional compounds of soybean seed (P<0.01) compared to control. The highest content of lipid and protein (25.4 and %33.8, respectively) observed by applying 0.75 g L-1 of ferrous nano-oxide and the lowest content was also in control. Changes in the trends of fatty acids profile (palmitic, oleic, linoleic and linolenic acids), some of mineral elements (Fe, Mg, Ca and P) and chlorophyll contents were similar to lipid and protein levels which by increasing in concentration of ferrous nano-oxide from 0 to 0.75 g L-1 all measured parameters also increased, but reduction in all parameters was observed in concentration from 0.75 to 1 g L-1. In conclusion, application of 0.75 to 1 g L-1 ferrous nano-oxide had the best effect on the nutrient composition of soybean seed.

  16. Ferrous-activated persulfate oxidation of arsenic(III) and diuron in aquatic system

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Lei [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China); Zheng, Wei [Jiangsu Product Quality Supervision and Inspection Research Institute, Nanjing 210007 (China); Ji, Yuefei [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China); Université Lyon 1, UMR CNRS 5256, Institut de recherches sur la catalyse et l’environnement de Lyon (IRCELYON), 2 Avenue Albert Einstein, F-69626 Villeurbanne (France); Zhang, Jinfeng; Zeng, Chao; Zhang, Ya; Wang, Qi [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China); Yang, Xi, E-mail: yangxi@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China)

    2013-12-15

    Highlights: • Effective oxidation of As(III)/diuron is achieved by Fe(II)-activated persulfate. • Hydroxyl and sulfate radical play important roles in As(III) and diuron oxidation. • CA and Na{sub 2}S{sub 2}O{sub 3} are efficient and environmental friendly chelating agents. • DFT calculation is found to be useful for degradation products prediction. -- Abstract: In situ chemical oxidation (ISCO) can be an effective technology for the remediation of soil and groundwater polluted by organic and inorganic contaminants. This study investigated the oxidation of arsenic(III) (As(III)) and diuron using ferrous activated persulfate-based ISCO. The results indicated that Fe(II)/persulfate oxidation could be an effective method to oxidize As(III) and diuron. Effects of pH, S{sub 2}O{sub 8}{sup 2−} and Fe(II) amounts on the destruction of As(III) and diuron were examined in batch experiments. Acidic conditions favored the removal of As(III) and diuron. Four chelating agents, citric acid (CA), Na{sub 2}S{sub 2}O{sub 3}, diethylene triamine pentaacetic acid (DTPA) and ethylene diamine tetraacetic acid disodium (EDTA-Na{sub 2}) were used in attempt to maintain the quantity of ferrous ion in solution. In our experiments, CA and Na{sub 2}S{sub 2}O{sub 3} were found to be more effective than DTPA and EDTA-Na{sub 2}. Our results also revealed a widely practical prospect of inorganic chelating agent Na{sub 2}S{sub 2}O{sub 3}. Hydroxyl and sulfate radical were determined to play key roles in the oxidation process by using ethanol and tertiary butanol as molecular probes. Oxidation of As(III) yielded As(V) via the electron-transfer reaction. In the oxidation process of diuron, a stepwise nucleophilic substitution of chlorine by hydroxyl and a stepwise oxidation process of the methyl on the dimethylurea group by hydroxyl and sulfate radical were proposed.

  17. Ferrous iron mediated oxidation of arachidonic acid: studies employing nitroblue tetrazolium (NBT).

    Science.gov (United States)

    Peterson, D A; Gerrard, J M; Rao, G H; Krick, T P; White, J G

    1978-10-01

    The oxidation of arachidonic acid by ferrous sulfate provides a useful model to study the role of iron in lipid oxidation reactions. We have employed nitroblue tetrazolium (NBT) in the present investigation to evaluate the mechanism of this reaction. In the presence of arachidonic acid, Fe +++, and O2, the yellow dye NBT was rapidly reduced to the blue form, NBTH2. The molar ratio of arachidonic acid to Fe++ in this rapid reaction was 1:1, showing an interaction of one fatty acid molecule per iron molecule. Approximately one molecule of NBT was reduced per four molecules of arachidonic acid and Fe++. Reduction of NBT was accompanied by oxidation of Fe++ to Fe+++, suggesting the transfer of four electrons from the Fe++ to NBT to reduce the dye. Arachidonic acid was found to be unchanged when extracted at the end of the reaction, indicating formation of a complex that could dissociate leaving intact arachidonic acid. Evidence for the presence of such a complex which slowly dissociates during the reaction was obtained after longer incubations with small amounts of arachidonic acid. NBT reduction was not inhibited by agents which hydrolyze superoxide, by catalase or by agents which trap hydroxy radicals. We, therefore, propose a model in which NBT traps a radical generated on the arachidonic acid molecule. The proposed model suggests mechanisms for other fatty acid oxidation reactions such as prostaglandin and hydroperoxy fatty acid synthesis.

  18. O2-mediated oxidation of ferrous nitrosylated human serum heme-albumin is limited by nitrogen monoxide dissociation

    International Nuclear Information System (INIS)

    Ascenzi, Paolo; Gullotta, Francesca; Gioia, Magda; Coletta, Massimo; Fasano, Mauro

    2011-01-01

    Research highlights: → Human serum heme-albumin displays globin-like properties. → O 2 -mediated oxidation of ferrous nitrosylated human serum heme-albumin. → Allosteric modulation of human serum heme-albumin reactivity. → Rifampicin is an allosteric effector of human serum heme-albumin. → Human serum heme-albumin is a ROS and NOS scavenger. -- Abstract: Human serum heme-albumin (HSA-heme-Fe) displays globin-like properties. Here, kinetics of O 2 -mediated oxidation of ferrous nitrosylated HSA-heme-Fe (HSA-heme-Fe(II)-NO) is reported. Values of the first-order rate constants for O 2 -mediated oxidation of HSA-heme-Fe(II)-NO (i.e., for ferric HSA-heme-Fe formation) and for NO dissociation from HSA-heme-Fe(II)-NO (i.e., for NO replacement by CO) are k = 9.8 x 10 -5 and 8.3 x 10 -4 s -1 , and h = 1.3 x 10 -4 and 8.5 x 10 -4 s -1 , in the absence and presence of rifampicin, respectively, at pH = 7.0 and T = 20.0 o C. The coincidence of values of k and h indicates that NO dissociation represents the rate limiting step of O 2 -mediated oxidation of HSA-heme-Fe(II)-NO. Mixing HSA-heme-Fe(II)-NO with O 2 does not lead to the formation of the transient adduct(s), but leads to the final ferric HSA-heme-Fe derivative. These results reflect the fast O 2 -mediated oxidation of ferrous HSA-heme-Fe and highlight the role of drugs in modulating allosterically the heme-Fe-atom reactivity.

  19. Quillaja saponaria bark saponin protects Wistar rats against ferrous sulphate-induced oxidative and inflammatory liver damage.

    Science.gov (United States)

    Ahmed Abdel-Reheim, Mustafa; Messiha, Basim Anwar Shehata; Abo-Saif, Ali Ahmed

    2017-12-01

    Saponins from different sources are historically reported in Chinese medicine to possess many beneficial effects. However, insufficient experimental data are available regarding the hepatoprotective potential of Quillaja bark saponin. The protective effect of Quillaja saponaria Molina (Quillajaceae) bark triterpenoid saponin against iron-induced hepatotoxicity is compared to the standard N-acetylcysteine in adult male Wistar rats. Animals were divided into (six) groups, namely a normal control, an N-acetylcysteine control (300 mg/kg/day, p.o., 10 days), a saponin control (100 mg/kg/day, p.o., for 10 days), a hepatotoxicity control (two doses of ferrous sulphate, 30 mg/kg/day each, i.p., on 9th and 10th day), an N-acetylcysteine plus ferrous sulphate (standard treatment) and a saponin plus ferrous sulphate (test treatment) group. Hepatocyte integrity loss markers (serum ALT, AST, ALP, GGT and LDH), oxidative stress markers (hepatic MDA, GSH and NO x ), dyslipidaemic markers (serum TC and TG) and hepatocyte functioning markers (serum bilirubin and albumin) were assessed. Quillaja bark saponin decreased iron-induced elevation of ALT (reaching 57% of hepatotoxicity control), AST (66%), ALP (76%), GGT (60%), LDH (54%), MDA (65%), NO x (77%), TC (70%), TG (54%), and total (54%), direct (54%) and indirect (54%) bilirubin, coupled with increased GSH (219%) and albumin (159%) levels. Histopathological study strongly supported biochemical estimations, while immunohistochemical study showed marked effect on eNOS and iNOS expression. Quillaja bark saponin has a good hepatoprotective effect. Amelioration of oxidative stress and suppression of NOS expression, with resultant maintenance of hepatocyte integrity and functioning, may explain this beneficial effect.

  20. Oxidation and diffusion process in the ferrous iron-bearing glass fibres near glass temperature

    DEFF Research Database (Denmark)

    Yue, Yuanzheng; Korsgaard, Martin; Kirkegaard, Lise

    2004-01-01

    modifier diffusion; 2) between the oxidation process and the glass transition. Based on these couplings, a phenomenological equation is proposed, which describes both kinetics and dynamics of the oxidation process of the Fe2+-bearing glass fibers. The equation can be used to predict the degree of oxidation......The Fe2+ oxidation and the network modifier diffusion in the Fe2+-bearing glass fibers are studied using differential scanning calorimetry (DSC), thermogravimetry (TG), and secondary neutral mass spectrometry (SNMS). The results show two couplings: 1) between the Fe2+ oxidation and the network...

  1. Arsenite and ferrous iron oxidation linked to chemolithotrophic denitrification for the immobilization of arsenic in anoxic environments

    Science.gov (United States)

    Sun, W.; Sierra-Alvarez, R.; Milner, L.; Oremland, R.; Field, J.A.

    2009-01-01

    The objective of this study was to explore a bioremediation strategy based on injecting NO3- to support the anoxic oxidation of ferrous iron (Fe(II)) and arsenite (As(III)) in the subsurface as a means to immobilize As in the form of arsenate (As(V)) adsorbed onto biogenic ferric (Fe(III)) (hydr)oxides. Continuous flows and filled columns were used to simulate a natural anaerobic groundwater and sediment system with co-occurring As(III) and Fe(II) in the presence (column SF1) or absence (column SF2) of nitrate, respectively. During operation for 250 days, the average influent arsenic concentration of 567 ??g L-1 was reduced to 10.6 (??9.6) ??g L-1 in the effluent of column SF1. The cumulative removal of Fe(II) and As(III) in SF1 was 6.5 to 10-fold higher than that in SF2. Extraction and measurement of the mass of iron and arsenic immobilized on the sand packing of the columns were close to the iron and arsenic removed from the aqueous phase during column operation. The dominant speciation of the immobilized iron and arsenic was Fe(III) and As(V) in SF1, compared with Fe(II) and As(III) in SF2. The speciation was confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results indicate that microbial oxidation of As(III) and Fe(II) linked to denitrification resulted in the enhanced immobilization of aqueous arsenic in anaerobic environments by forming Fe(III) (hydr)oxide coated sands with adsorbed As(V). ?? 2009 American Chemical Society.

  2. Advanced treatment of effluents from an industrial park wastewater treatment plant by ferrous ion activated persulfate oxidation process.

    Science.gov (United States)

    Zhu, Songmei; Zhou, Zhen; Jiang, Haitao; Ye, Jianfeng; Ren, Jiamin; Gu, Lingyun; Wang, Luochun

    The advanced oxidation technology, ferrous ion (Fe(II)) activated persulfate (PS) producing sulfate radicals, was used for the advanced treatment of effluent from an integrated wastewater treatment plant in a papermaking industrial park. Separate and interactive effects of PS dosage, Fe(II)/PS ratio and initial pH on chemical oxygen demand (COD) removal were analyzed by the response surface methodology (RSM). The results showed that Fe(II)-PS system was effective in COD removal from the secondary effluent. PS dosage was the most dominant factor with positive influence on COD removal, followed by initial pH value. The optimum conditions with COD removal of 54.4% were obtained at PS/COD of 2.2, initial pH of 6.47 and Fe(II)/PS of 1.89. UV-visible spectrum analysis showed that after RSM optimization, Fe(II)-PS system effectively degraded large organic molecules into small ones, and decreased humification degree of the effluent. Three-dimensional fluorescence analysis demonstrated that aromatic protein and fulvic substances were fully decomposed by the Fe(II)-PS treatment.

  3. Ferrous sulfate, but not iron polymaltose complex, aggravates local and systemic inflammation and oxidative stress in dextran sodium sulfate-induced colitis in rats

    Directory of Open Access Journals (Sweden)

    Toblli JE

    2015-05-01

    Full Text Available Jorge E Toblli, Gabriel Cao, Margarita Angerosa Laboratory of Experimental Medicine, Hospital Alemán, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina Background and aims: Iron deficiency is common in inflammatory bowel disease, yet oral iron therapy may worsen the disease symptoms and increase systemic and local oxidative stress. The aim of this study was to compare the effects of oral ferrous sulfate and iron polymaltose complex on inflammatory and oxidative stress markers in colitic rats.Methods: Animals were divided into four groups with ten animals each. Rats of three groups received dextran sodium sulfate to induce colitis and animals of two of these groups received 5 mg iron/kg of body weight a day, as ferrous sulfate or iron polymaltose complex, for 7 days. Gross colon anatomy, histology of colon and liver, stainings of L-ferritin, Prussian blue, hepcidin, tumor necrosis factor-α, and interleukin-6, as well serum levels of liver enzymes, inflammatory markers, and iron markers, were assessed.Results: Body weight, gross anatomy, crypt injury and inflammation scores, inflammatory parameters in liver and colon, as well as serum and liver hepcidin levels were not significantly different between colitic animals without iron treatment and colitic animals treated with iron polymaltose complex. In contrast, ferrous sulfate treatment caused significant worsening of these parameters. As opposed to ferrous sulfate, iron polymaltose complex caused less or no additional oxidative stress in the colon and liver compared to colitic animals without iron treatment.Conclusion: Iron polymaltose complex had negligible effects on colonic tissue erosion, local or systemic oxidative stress, and local or systemic inflammation, even at high therapeutic doses, and may thus represent a valuable oral treatment of iron deficiency in inflammatory bowel disease. Keywords: preclinical, oral iron treatment, tolerability, colonic tissue erosion

  4. Hydroxylamine-induced oxidation of ferrous carbonylated truncated hemoglobins from Mycobacterium tuberculosis and Campylobacter jejuni is limited by carbon monoxide dissociation.

    Science.gov (United States)

    Ascenzi, Paolo; Ciaccio, Chiara; Gasperi, Tecla; Pesce, Alessandra; Caporaso, Lucia; Coletta, Massimo

    2017-08-01

    Hydroxylamine (HA) is an oxidant of ferrous globins and its action has been reported to be inhibited by CO, even though this mechanism has not been clarified. Here, kinetics of the HA-mediated oxidation of ferrous carbonylated Mycobacterium tuberculosis truncated hemoglobin N and O (Mt-trHbN(II)-CO and Mt-trHbO(II)-CO, respectively) and Campylobacter jejuni truncated hemoglobin P (Cj-trHbP(II)-CO), at pH 7.2 and 20.0 °C, are reported. Mixing Mt-trHbN(II)-CO, Mt-trHbO(II)-CO, and Cj-trHbP(II)-CO solution with the HA solution brings about absorption spectral changes reflecting the disappearance of the ferrous carbonylated derivatives with the concomitant formation of the ferric species. HA oxidizes irreversibly Mt-trHbN(II)-CO, Mt-trHbO(II)-CO, and Cj-trHbP(II)-CO with the 1:2 stoichiometry. The dissociation of CO turns out to be the rate-limiting step for the oxidation of Mt-trHbN(II)-CO, Mt-trHbO(II)-CO, and Cj-trHbP(II)-CO by HA. Values of the second-order rate constant for HA-mediated oxidation of Mt-trHbN(II)-CO, Mt-trHbO(II)-CO, and Cj-trHbP(II)-CO range between 8.8 × 10 4 and 8.6 × 10 7 M -1 s -1 , reflecting different structural features of the heme distal pocket. This study (1) demonstrates that the inhibitory effect of CO is linked to the dissociation of this ligand, giving a functional basis to previous studies, (2) represents the first comparative investigation of the oxidation of ferrous carbonylated bacterial 2/2 globins belonging to the N, O, and P groups by HA, (3) casts light on the correlation between kinetics of HA-mediated oxidation and carbonylation of globins, and (4) focuses on structural determinants modulating the HA-induced oxidation process.

  5. Fish Proteins as Targets of Ferrous-Catalyzed Oxidation: Identification of Protein Carbonyls by Fluorescent Labeling on Two-Dimensional Gels and MALDI-TOF/TOF Mass Spectrometry

    DEFF Research Database (Denmark)

    Pazos, Manuel; da Rocha, Angela Pereira; Roepstorff, Peter

    2011-01-01

    Protein oxidation in fish meat is considered to affect negatively the muscle texture. An important source of free radicals taking part in this process is Fenton's reaction dependent on ferrous ions present in the tissue. The aim of this study was to investigate the susceptibility of cod muscle...... proteins in sarcoplasmic and myofibril fractions to in vitro metal-catalyzed oxidation and to point out protein candidates that might play a major role in the deterioration of fish quality. Extracted control proteins and proteins subjected to free radicals generated by Fe(II)/ascorbate mixture were labeled...

  6. Ferrous ion as a reducing agent in the generation of antibiofilm nitric oxide from a copper-based catalytic system.

    Science.gov (United States)

    Wonoputri, Vita; Gunawan, Cindy; Liu, Sanly; Barraud, Nicolas; Yee, Lachlan H; Lim, May; Amal, Rose

    2018-01-31

    The work found that the electron-donating properties of ferrous ions (Fe 2+ ) can be used for the conversion of nitrite (NO 2 - ) into the biofilm-dispersing signal nitric oxide (NO) by a copper(II) complex (CuDTTCT) catalyst, a potentially applicable biofilm control technology for the water industries. The availability of Fe 2+ varied depending on the characteristics of the aqueous systems (phosphate- and carbonate-containing nitrifying bacteria growth medium, NBGM and phosphate buffered saline, PBS at pH 6 to 8, to simulate conditions typically present in the water industries) and was found to affect the production of NO from nitrite by CuDTTCT (casted into PVC). Greater amounts of NO were generated from the CuDTTCT-nitrite-Fe 2+ systems in PBS compared to those in NBGM, which was associated with the reduced extent of Fe 2+ -to-Fe 3+ autoxidation by the iron-precipitating moieties phosphates and carbonate in the former system. Further, acidic conditions at pH 6.0 were found to favor NO production from the catalytic system in both PBS and NBGM compared to neutral or basic pH (pH 7.0 or 8.0). Lower pH was shown to stabilize Fe 2+ and reduce its autoxidation to Fe 3+ . These findings will be beneficial for the potential implementation of the NO-generating catalytic technology and indeed, a 'non-killing' biofilm dispersal activity of CuDTTCT-nitrite-Fe 2+ was observed on nitrifying bacteria biofilms in PBS at pH 6. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Oxidative degradation of propachlor by ferrous and copper ion activated persulfate.

    Science.gov (United States)

    Liu, C S; Shih, K; Sun, C X; Wang, F

    2012-02-01

    The process of in situ chemical oxidation (ISCO) by persulfate (S(2)O(8)(2-)) can be accelerated by metal ion activation, which more effectively degrades subsurface pollutants by enhancing sulfate radical (SO(4)(-)) generation. This study compared the results of propachlor degradation by Cu(2+) and Fe(2+) activated persulfate and revealed differing degradation kinetics and mechanisms between the two types of activation system. The activation of persulfate by Fe(2+) ions generally resulted in rapid degradation in the early stage, but was accompanied by a dramatic decrease in efficiency due to the rapid depletion of Fe(2+) by the sulfate radicals generated. In contrast, the Cu(2+) activated persulfate had a longer lasting degradation effect and a proportionally greater degradation enhancement at elevated Cu(2+) concentrations. An optimal Fe(2+) concentration should be sought to activate the persulfate, as a high Fe(2+) concentration of 2.5mM or above, as was used in this study, may inhibit propachlor degradation due to the competitive consumption of sulfate radicals by the excess Fe(2+) ions. Higher temperatures (55°C compared with 30°C) resulted in enhanced metal activation, particularly with the Cu(2+) activated system. Furthermore, acidic conditions were found to be more favorable for propachlor degradation by metal activated persulfate. The ecotoxicity of degraded propachlor samples, which was indicated by average well color development (AWCD) for its microbial community activity, was confirmed to be decreased during the degradation processes with these two ions activated persulfate. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. The selectivity of Vibrio cholerae H-NOX for gaseous ligands follows the "sliding scale rule" hypothesis. Ligand interactions with both ferrous and ferric Vc H-NOX.

    Science.gov (United States)

    Wu, Gang; Liu, Wen; Berka, Vladimir; Tsai, Ah-lim

    2013-12-31

    Vc H-NOX (or VCA0720) is an H-NOX (heme-nitric oxide and oxygen binding) protein from facultative aerobic bacterium Vibrio cholerae. It shares significant sequence homology with soluble guanylyl cyclase (sGC), a NO sensor protein commonly found in animals. Similar to sGC, Vc H-NOX binds strongly to NO and CO with affinities of 0.27 nM and 0.77 μM, respectively, but weakly to O2. When positioned on a "sliding scale" plot [Tsai, A.-l., et al. (2012) Biochemistry 51, 172-186], the line connecting log K(D)(NO) and log K(D)(CO) of Vc H-NOX can almost be superimposed with that of Ns H-NOX. Therefore, the measured affinities and kinetic parameters of gaseous ligands to Vc H-NOX provide more evidence to validate the "sliding scale rule" hypothesis. Like sGC, Vc H-NOX binds NO in multiple steps, forming first a six-coordinate heme-NO complex at a rate of 1.1 × 10(9) M(-1) s(-1), and then converts to a five-coordinate heme-NO complex at a rate that is also dependent on NO concentration. Although the formation of oxyferrous Vc H-NOX cannot be detected at a normal atmospheric oxygen level, ferrous Vc H-NOX is oxidized to the ferric form at a rate of 0.06 s(-1) when mixed with O2. Ferric Vc H-NOX exists as a mixture of high- and low-spin states and is influenced by binding to different ligands. Characterization of both ferric and ferrous Vc H-NOX and their complexes with various ligands lays the foundation for understanding the possible dual roles in gas and redox sensing of Vc H-NOX.

  9. Enhancing the electrochemical oxidation of acid-yellow 36 azo dye using boron-doped diamond electrodes by addition of ferrous ion

    Energy Technology Data Exchange (ETDEWEB)

    Villanueva-Rodriguez, M.; Hernandez-Ramirez, A. [Universidad Autonoma de Nuevo Leon, Facultad de Ciencias Quimicas, Av. Universidad s/n, Cd. Universitaria, San Nicolas de los Garza, NL. 66400 (Mexico); Peralta-Hernandez, J.M., E-mail: jperalta@fcq.uanl.mx [Universidad Autonoma de Nuevo Leon, Facultad de Ciencias Quimicas, Av. Universidad s/n, Cd. Universitaria, San Nicolas de los Garza, NL. 66400 (Mexico); Bandala, Erick R.; Quiroz-Alfaro, Marco A. [Universidad de Las Americas - Puebla, Escuela de Ingenieria y Ciencias, Sta. Catarina Martir - Cholula, Puebla 72820 (Mexico)

    2009-08-15

    This work shows preliminary results on the electrochemical oxidation process (EOP) using boron-doped diamond (BDD) electrode for acidic yellow 36 oxidation, a common azo dye used in textile industry. The study is centred in the synergetic effect of ferrous ions and hydroxyl free radicals for improving discoloration of azo dye. The assays were carried out in a typical glass cell under potentiostatic conditions. On experimental conditions, the EOP was able to partially remove the dye from the reaction mixture. The reaction rate increased significantly by addition of Fe{sup 2+} (1 mM as ferrous sulphate) to the system and by (assumed) generation of ferrate ion [Fe(VI)] over BDD electrode. Ferrate is considered as a highly oxidizing reagent capable of removing the colorant from the reaction mixture, in synergistic action with the hydroxyl radicals produced on the BDD surface. Further increases in the Fe{sup 2+} concentration lead to depletion of the reaction rate probably due to the hydroxyl radical scavenging effect of Fe{sup 2+} excess in the system.

  10. Fish proteins as targets of ferrous-catalyzed oxidation: identification of protein carbonyls by fluorescent labeling on two-dimensional gels and MALDI-TOF/TOF mass spectrometry.

    Science.gov (United States)

    Pazos, Manuel; da Rocha, Angela Pereira; Roepstorff, Peter; Rogowska-Wrzesinska, Adelina

    2011-07-27

    Protein oxidation in fish meat is considered to affect negatively the muscle texture. An important source of free radicals taking part in this process is Fenton's reaction dependent on ferrous ions present in the tissue. The aim of this study was to investigate the susceptibility of cod muscle proteins in sarcoplasmic and myofibril fractions to in vitro metal-catalyzed oxidation and to point out protein candidates that might play a major role in the deterioration of fish quality. Extracted control proteins and proteins subjected to free radicals generated by Fe(II)/ascorbate mixture were labeled with fluorescein-5-thiosemicarbazide (FTSC) to tag carbonyl groups and separated by two-dimensional gel electrophoresis. Consecutive visualization of protein carbonyl levels by capturing the FTSC signal and total protein levels by capturing the SyproRuby staining signal allowed us to quantify the relative change in protein carbonyl levels corrected for changes in protein content. Proteins were identified using MALDI-TOF/TOF mass spectrometry and homology-based searches. The results show that freshly extracted cod muscle proteins exhibit a detectable carbonylation background and that the incubation with Fe(II)/ascorbate triggers a further oxidation of both sarcoplasmic and myofibril proteins. Different proteins exhibited various degrees of sensitivity to oxidation processes. Glyceraldehyde 3-phosphate dehydrogenase (GAPDH), nucleoside diphosphate kinase B (NDK), triosephosphate isomerase, phosphoglycerate mutase, lactate dehydrogenase, creatine kinase, and enolase were the sarcoplasmic proteins most vulnerable to ferrous-catalyzed oxidation. Moreover, NDK, phosphoglycerate mutase, and GAPDH were identified in several spots differing by their pI, and those forms showed different susceptibilities to metal-catalyzed oxidation, indicating that post-translational modifications may change the resistance of proteins to oxidative damage. The Fe(II)/ascorbate treatment significantly

  11. The magnetic and oxidation behavior of bare and silica-coated iron oxide nanoparticles synthesized by reverse co-precipitation of ferrous ion (Fe{sup 2+}) in ambient atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Mahmed, N., E-mail: norsuria.mahmed@aalto.fi [Aalto University School of Chemical Technology, Department of Materials Science and Engineering, P.O. Box 16200, FI-00076 Aalto (Finland); School of Materials Engineering, Kompleks Pusat Pengajian UniMAP, Taman Muhibbah, Universiti Malaysia Perlis, 02600 Jejawi, Perlis (Malaysia); Heczko, O., E-mail: heczko@fzu.cz [Institute of Physics, Academy of Sciences, Czech Republic Na Slovance 2, CZ-182 21 Praha 8 (Czech Republic); Lancok, A., E-mail: Lancok@seznam.cz [Institute of Physics, Academy of Sciences, Czech Republic Na Slovance 2, CZ-182 21 Praha 8 (Czech Republic); Hannula, S-P., E-mail: simo-pekka.hannula@aalto.fi [Aalto University School of Chemical Technology, Department of Materials Science and Engineering, P.O. Box 16200, FI-00076 Aalto (Finland)

    2014-03-15

    The synthesis of iron oxide nanoparticles, i.e., magnetite was attempted by using only ferrous ion (Fe{sup 2+}) as a magnetite precursor, under an ambient atmosphere. The room temperature reverse co-precipitation method was used, by applying two synthesis protocols. The freshly prepared iron oxide was also immediately coated with Stöber silica (SiO{sub 2}) layer, forming the coreshell structure. The phase, stoichiometry, crystallite and the particle size of the synthesized powders were determined by using X-ray diffraction (XRD) and transmission electron microscope (TEM), while the magnetic and oxidation behaviors were studied by using the vibrating sample magnetometer (VSM) and Mössbauer spectroscopy. Based on the results, the bare iron oxide nanoparticles are in the stoichiometry between the magnetite and the maghemite stoichiometry, i.e., oxidation occurs. This oxidation is depending on the synthesis protocols used. With the silica coating, the oxidation can be prevented, as suggested by the fits of Mössbauer spectra and low temperature magnetic measurement. - Highlights: • Synthesis of magnetite was attempted by using ferrous ion (Fe{sup 2+}) in air. • The synthesized particle has a stoichiometry in between magnetite and maghemite. • Silica shell partly prevented the oxidation as suggested by magnetic and Mössbauer study.

  12. Application of ferrous-chromate and idometric titration for the determination of copper oxidation states in the superconductor YBa2Cu3Oy

    International Nuclear Information System (INIS)

    Oku, Masaoki; Kimura, Jin; Hosoya, Minoru; Takada, Kunio; Hirokawa, Kichinosuke

    1988-01-01

    Oxidation-reduction titration methods, Fe 2+ -Cr 2 O 7 2- and I - -S 2 O 3 2- , were applied to the determination of the oxidation state of copper in the superconductor YBa 2 Cu 3 O y and related compounds. The former method presented problems in the sample dissolution and titration steps. The dissolution of the sample in low concentrations of Fe 2+ -phosphoric acid and Fe 2+ -perchloric acid takes place in two steps, the oxidation of Fe 2+ to Fe 3+ and the liberation of oxygen gas, when the liberation results in low analytical values for Cu 3+ . In addition the coexistence of cuprous ion and acids induces the oxidation of ferrous ion by dissolved oxygen and air. The problems were resolved by dissolution in 0.1 mol/l Fe 2+ -phosphoric acid and titration in an argon atmosphere. The latter method gave good results by controlling the amounts of potassium chloride, the concentration of acetic acid, and by elimination of the dissolved oxygen in acetic acid solution. The results of the two titration methods coincided with each other. (orig.)

  13. An experimental study on ferrous iron photo-oxidation: Effect of the solar spectrum on the surface for acidification of surface water in the early Hesperian Mars

    Science.gov (United States)

    Tabata, H.; Sekine, Y.; Kanzaki, Y.; Sugita, S.; Murakami, T.

    2017-12-01

    Geochemical evidence obatined by Mars Opportunity rover suggests that the pH of Martian surface water shifted to highly acidic, i.e., pH 2-4, in the early Hesperian (e.g., Tosca et al., 2005). Hurowitz et al. (2010) proposed that solar UV light may have promoted the acidification through photo-oxidation of ferrous iron dissolved in upwelling groundwater on early Mars. However, the trigger for the acidification in the early Hesperian remains unclear. The photo-oxidation of Fe2+ occurs under acidic conditions, i.e., pH UV light (UV/visible light (300-400 nm). Thus, the efficiency of acidification through photo-oxidation on early Mars should have depended on the solar spectrum on the surface at that time which is determined by the atmospheric composition. To investigate the effect of UV spectrum on the acidification, we conducted two types of laboratory experiments: One used a Xe lamp as the light source for photo-oxidation of ferrous iron to irradiate light with continuous spectrum from 250 to 400 nm, and the other used the Xe lamp with an optical filter that cuts off UV light shorter than 300 nm. The pH value of the starting solution was around 7. Upon the UV irradiation covering full wavelength range (250-400 nm), the pH value of the solution decreases down to less than 4, consistent with the proposed pH of the Hesperian acidic water on Meridiani Planum (Tosca et al., 2005). This occurs because Fe2+ is stable at pH UV light in 250-300 nm. When the UV irradiation covering 300-400 nm, the pH value of the solution also decreases to pH 5 immediately after the UV irradiation. However, it does not decrease less than pH 5 and reaches a steady state. This is the case because FeOH+ is converted into Fe2+ at low pH, which prevents further photo-oxidation by light in 300-400 nm. These results suggest that a change in the atmospheric composition and consequent reaching of UV light in the wavelength < 300 nm may have played a key role for triggering the acidification in the

  14. Ferrous Sulfate (Iron)

    Science.gov (United States)

    ... are allergic to ferrous sulfate, any other medications tartrazine (a yellow dye in some processed foods and ... in, tightly closed, and out of reach of children. Store it at room temperature and away from ...

  15. Ferrous Metal Processing Plants

    Data.gov (United States)

    Department of Homeland Security — This map layer includes ferrous metal processing plants in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...

  16. The ferrous-dioxy complex of neuronal nitric oxide synthase. Divergent effects of L-arginine and tetrahydrobiopterin on its stability.

    Science.gov (United States)

    Abu-Soud, H M; Gachhui, R; Raushel, F M; Stuehr, D J

    1997-07-11

    Nitric oxide synthases (NOS) are hemeproteins that catalyze oxidation of L-arginine to nitric oxide (NO) and citrulline. The NOS heme iron is expected to participate in oxygen activation during catalysis, but its interactions with O2 are not characterized. We utilized the heme-containing oxygenase domain of neuronal NOS (nNOSoxy) and stopped-flow methods to study formation and autooxidative decomposition of the nNOSoxy oxygenated complex at 10 degrees C. Mixing ferrous nNOSoxy with air-saturated buffer generated a transient species with absorption maxima at 427 and approximately 560 nm. This species decayed within 1 s to form ferric nNOSoxy. Its formation was first order with respect to O2, monophasic, and gave rate constants for kon = 9 x 10(5) M-1 s-1 and koff = 108 s-1 for an L-arginine- and tetrahydrobiopterin (H4B)-saturated nNOSoxy. Omission of L-arginine and/or H4B did not greatly effect O2 binding and dissociation rates. Decomposition of the oxygenated intermediate was independent of O2 concentration and was either biphasic or monophasic depending on sample conditions. L-Arginine stabilized the oxygenated intermediate (decay rate = 0.14 s-1), while H4B accelerated its decay by a factor of 70 irrespective of L-arginine. The spectral and kinetic properties of the intermediate identify it as the FeIIO2 complex of nNOSoxy. Destabilization of a metallo-oxy species by H4B is unprecedented and may be important regarding the role of this cofactor in NO synthesis.

  17. Protective Effects of α-tocopherol on the Activity and Antioxidant Profile of Bovine Spermatozoa Subjected to Ferrous Ascorbate-Induced Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Eva Tvrdá

    2016-01-01

    Full Text Available As spermatozoa are highly vulnerable to oxidative stress development, in vitro antioxidants offer an additional line of defense to the male reproductive system against oxidative insults. α‑tocopherol (α-TOC is the most abundant form of vitamin E identified in the seminal plasma and spermatozoa membranes, being able to terminate numerous oxidative chain reactions causing substantial damage to biomolecules vital for sperm survival. This study was designed to shed more light on the in vitro effects of α‑tocopherol with respect to the vitality and intracellular antioxidant profile of bovine spermatozoa subjected to ferrous ascorbate-induced oxidative stress. Spermatozoa were washed out from 50 bovine ejaculates, suspended in 2.9 % sodium citrate and subjected to α-TOC treatment (10, 50, 100 and 500 μmol/L in the presence or absence of ferrous ascorbate (FeAA; 150 μmol/L FeSO4 and 750 μmol/L ascorbic acid during a 6h in vitro culture. Spermatozoa motion parameters were assessed using the SpermVision™ computer-aided sperm analysis (CASA system. Cell viability was examined with the metabolic activity (MTT assay, and the nitroblue-tetrazolium (NBT test was applied to quantify the intracellular superoxide formation. Cell lysates were prepared at the end of the experiments in order to assess the intracellular activity of superoxide dismutase (SOD, catalase (CAT, as well as glutathione (GSH and malondialdehyde (MDA concentrations. Treatment with FeAA reduced both spermatozoa motility parameters (P < 0.001 as well as viability (P < 0.05 with respect to Time 0 h; P < 0.01 in case of Time 2 h and P < 0.001 in relation to Time 6 h, decreased the antioxidant parameters of the samples (P < 0.001 in case of SOD; P < 0.01 with respect to CAT and GSH but increased the superoxide production (P < 0.01 in case of Time 0h and P < 0.001 with respect to Times 2 h and 6 h and lipid peroxidation (P < 0.001. α‑TOC administration resulted in a preservation of

  18. Tert-butylhydroquinone protects PC12 cells against ferrous sulfate-induced oxidative and inflammatory injury via the Nrf2/ARE pathway.

    Science.gov (United States)

    Xu, Wenzhe; Li, Feng; Xu, Zhenkuan; Sun, Bin; Cao, Jingwei; Liu, Yuguang

    2017-08-01

    Increasing evidence had proved the critical role of iron in the pathogenesis of numerous neurodegenerative diseases because of its capacity to promote the formation of reactive oxygen species (ROS). Tert-butylhydroquinone (tBHQ) was a metabolite of butylated hydroxyanisole, a widely used food antioxidant. This study was aimed to investigate the protective effects of tBHQ on a cellular model of neurodegenerative disease, which was established in PC12 cells by exposure to ferrous sulfate (FS), and elucidate the potential protective mechanisms. The results showed that FS exposure increased lactate dehydrogenase (LDH) release and cell apoptosis in PC12 cells, accompanied by significant increases in the bax/bcl-2 ratio, cytochrome c release, and caspase-3 cleavage. It also enhanced the ROS production, malondialdehyde (MDA) content (lipid peroxidation), γ-H2A.X formation (DNA damage), and promoted nuclear factor kappa B (NF-κB) activation and expressions of cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). tBHQ pretreatment alleviated FS-induced LDH release, cell apoptosis, oxidative stress and inflammatory response by promoting Nrf2 nuclear translocation and the protein levels of Nrf2 downstream target genes heme oxygenase-1 (Hmox-1), nicotinamide adenine dinucleotide phosphate (NADPH): quinone oxidoreductase-1 (Nqo1) and glutathione peroxidase-1 (Gpx1). tBHQ alleviated the FS-induced LDH release in control siRNA-treated PC12 cells, but failed to alleviate FS-induced LDH release in Nrf2 siRNA-treated cells. These findings suggested that pretreatment with tBHQ protected PC12 cells from FS-induced oxidative and inflammatory injury via the Nrf2/ARE pathway. tBHQ was promising as a potential therapeutic agent for neurodegenerative diseases induced by iron toxicity and should be encouraged for further research. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Ferrous Iron Oxidation under Varying pO2 Levels: The Effect of Fe(III)/Al(III) Oxide Minerals and Organic Matter.

    Science.gov (United States)

    Chen, Chunmei; Thompson, Aaron

    2018-01-16

    Abiotic Fe(II) oxidation by O 2 commonly occurs in the presence of mineral sorbents and organic matter (OM) in soils and sediments; however, this tertiary system has rarely been studied. Therefore, we examined the impacts of mineral surfaces (goethite and γ-Al 2 O 3 ) and organic matter [Suwannee River fulvic acid (SRFA)] on Fe(II) oxidation rates and the resulting Fe(III) (oxyhydr)oxides under 21 and 1% pO 2 at pH 6. We tracked Fe dynamics by adding 57 Fe(II) to 56 Fe-labeled goethite and γ-Al 2 O 3 and characterized the resulting solids using 57 Fe Mössbauer spectroscopy. We found Fe(II) oxidation was slower at low pO 2 and resulted in higher-crystallinity Fe(III) phases. Relative to oxidation of Fe(II) (aq) alone, both goethite and γ-Al 2 O 3 surfaces increased Fe(II) oxidation rates regardless of pO 2 levels, with goethite being the stronger catalyst. Goethite surfaces promoted the formation of crystalline goethite, while γ-Al 2 O 3 favored nano/small particle or disordered goethite and some lepidocrocite; oxidation of Fe(II) aq alone favored lepidocrocite. SRFA reduced oxidation rates in all treatments except the mineral-free systems at 21% pO 2 , and SRFA decreased Fe(III) phase crystallinity, facilitating low-crystalline ferrihydrite in the absence of mineral sorbents, low-crystalline lepidocrocite in the presence of γ-Al 2 O 3 , but either crystalline goethite or ferrihydrite when goethite was present. This work highlights that the oxidation rate, the types of mineral surfaces, and OM control Fe(III) precipitate composition.

  20. Effects of differences in the timing of ferrous sulfate supplementation on lipid peroxidation and activation of NF-κB in the placenta of pregnant rats

    Directory of Open Access Journals (Sweden)

    Alfi Noviyana

    2017-10-01

    Conclusion: In conclusion, administration of ferrous sulfate will induce placental oxidative damage. Increased activation of NF-κB is underlain by changes in the degree of oxidative stress in the placenta from administration of ferrous sulfate.

  1. Protective effects of pulmonary epithelial lining fluid on oxidative stress and DNA single-strand breaks caused by ultrafine carbon black, ferrous sulphate and organic extract of diesel exhaust particles

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, Hsiao-Chi [School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan (China); Cheng, Yi-Ling; Lei, Yu-Chen [Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan (China); Chang, Hui-Hsien [Institute of Environmental Health, College of Public Health, National Taiwan University, Taipei, Taiwan (China); Cheng, Tsun-Jen, E-mail: tcheng@ntu.edu.tw [Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan (China); Department of Public Health, College of Public Health, National Taiwan University, Taipei, Taiwan (China)

    2013-02-01

    Pulmonary epithelial lining fluid (ELF) is the first substance to make contact with inhaled particulate matter (PM) and interacts chemically with PM components. The objective of this study was to determine the role of ELF in oxidative stress, DNA damage and the production of proinflammatory cytokines following physicochemical exposure to PM. Ultrafine carbon black (ufCB, 15 nm; a model carbonaceous core), ferrous sulphate (FeSO{sub 4}; a model transition metal) and a diesel exhaust particle (DEP) extract (a model organic compound) were used to examine the acellular oxidative potential of synthetic ELF and non-ELF systems. We compared the effects of exposure to ufCB, FeSO{sub 4} and DEP extract on human alveolar epithelial Type II (A549) cells to determine the levels of oxidative stress, DNA single-strand breaks and interleukin-8 (IL-8) production in ELF and non-ELF systems. The effects of ufCB and FeSO{sub 4} on the acellular oxidative potential, cellular oxidative stress and DNA single-strand breakage were mitigated significantly by the addition of ELF, whereas there was no decrease following treatment with the DEP extract. There was no significant effect on IL-8 production following exposure to samples that were suspended in ELF/non-ELF systems. The results of the present study indicate that ELF plays an important role in the initial defence against PM in the pulmonary environment. Experimental components, such as ufCB and FeSO{sub 4}, induced the production of oxidative stress and led to DNA single-strand breaks, which were moderately prevented by the addition of ELF. These findings suggest that ELF plays a protective role against PM-driven oxidative stress and DNA damage. -- Highlights: ► To determine the role of ELF in ROS, DNA damage and IL-8 after exposure to PM. ► ufCB, FeSO{sub 4} and DEP extract were used to examine the protective effects of ELF. ► PM-driven oxidative stress and DNA single-strand breakage were mitigated by ELF. ► The findings

  2. Technetium behavior in sulfide and ferrous iron solutions

    International Nuclear Information System (INIS)

    Lee, S.Y.; Bondietti, E.A.

    1982-01-01

    Pertechnetate oxyanion ( 99 TcO 4- ), a potentially mobile species in leachate from a breached radioactive waste repository, was removed from a brine solution by precipitation with sulfide, iron, and ferrous sulfide at environmental pH's. Maghemite (ν-Fe 2 O 3 ) and geothite (α-FeOOH) were the dominant minerals in the precipitate obtained from the TcO 4- -ferrous iron reaction. The observation of small particle size and poor crystallinity of the minerals formed in the presence of Tc suggested that the Tc was incorporated into the mineral structure after reduction to a lower valence state. Amorphous ferrous sulfide, an initial phase precipitating in the TcO 4- -ferrous iron-sulfide reaction, was transformed to goethite and hematite (α-Fe 2 O 3 ) on aging. The black precipitate obtained from the TcO 4- -sulfide reaction was poorly crystallized technetium sulfide (Tc 2 S 7 ) which was insoluble in both acid and alkaline solution in the absence of strong oxidents. The results suggested that ferrous- and/or sulfide-bearing groundwaters and minerals in host rocks or backfill barriers could reduce the mobility of Tc through the formation of less-soluble Tc-bearing iron and/or sulfide minerals

  3. The magnetic and oxidation behavior of bare and silica-coated iron oxide nanoparticles synthesized by reverse co-precipitation of ferrous ion (Fe.sup.2+./sup.) in ambient atmosphere

    Czech Academy of Sciences Publication Activity Database

    Mahmed, N.; Heczko, Oleg; Lančok, Adriana; Hannula, S.-P.

    2014-01-01

    Roč. 353, MAR (2014), s. 15-22 ISSN 0304-8853 R&D Projects: GA ČR(CZ) GAP107/11/0391 Institutional support: RVO:68378271 Keywords : reverseco-precipitation * ferrousion * magnetite * Mössbauer * silica Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.970, year: 2014 http://www.sciencedirect.com/science/article/pii/S0304885313007336

  4. 21 CFR 184.1311 - Ferrous lactate.

    Science.gov (United States)

    2010-04-01

    ... prepared by reacting calcium lactate or sodium lactate with ferrous sulfate, direct reaction of lactic acid with iron filings, reaction of ferrous chloride with sodium lactate, or reaction of ferrous sulfate with ammonium lactate. (b) The ingredient meets the specifications of the Food Chemicals Codex, 4th ed...

  5. Hyperfine interactions and structures of ferrous hydroxide and green rust II in sulfated aqueous media

    International Nuclear Information System (INIS)

    Olowe, A.A.; Genin, J.M.R.; Bauer, P.

    1988-01-01

    A sulfated ferrous hydroxide is obtained by mixing NaOH with melanterite depending on the R = [SO 4 -- ]/[OH - ] ratio and leading by oxidation to the green rust II transient compound. Hyperfine parameters are presented. (orig.)

  6. Organic contaminants degradation from the S(IV) autoxidation process catalyzed by ferrous-manganous ions: A noticeable Mn(III) oxidation process.

    Science.gov (United States)

    Zhang, Jiaming; Ma, Jun; Song, Haoran; Sun, Shaofang; Zhang, Zhongxiang; Yang, Tao

    2018-04-15

    Remarkable atrazine degradation in the S(IV) autoxidation process catalyzed by Fe 2+ -Mn 2+ (Fe 2+ /Mn 2+ /sulfite) was demonstrated in this study. Competitive kinetic experiments, alcohol inhibiting methods and electron spin resonance (ESR) experiments proved that sulfur radicals were not the major oxidation species. Mn(III) was demonstrated to be the primary active species in the Fe 2+ /Mn 2+ /sulfite process based on the comparison of oxidation selectivity. Moreover, the inhibiting effect of the Mn(III) hydrolysis and the S(IV) autoxidation in the presence of organic contaminants indicated the existence of three Mn(III) consumption routes in the Fe 2+ /Mn 2+ /sulfite process. The absence of hydroxyl radical and sulfate radical was interpreted by the competitive dynamics method. The oxidation capacity of the Fe 2+ /Mn 2+ /sulfite was independent of the initial pH (4.0-6.0) because the fast decay of S(IV) decreased initial pH below 4.0 rapidly. The rate of ATZ degradation was independent of the dissolved oxygen (DO) because that the major DO consumption process was not the rate determining step during the production of SO 5 •- . Phosphate and bicarbonate were confirmed to have greater inhibitory effects than other environmental factors because of their strong pH buffering capacity and complexing capacity for Fe 3+ . The proposed acetylation degradation pathway of ATZ showed the application of the Fe 2+ /Mn 2+ /sulfite process in the research of contaminants degradation pathways. This work investigated the characteristics of the Fe 2+ /Mn 2+ /sulfite process in the presence of organic contaminants, which might promote the development of Mn(III) oxidation technology. Copyright © 2018. Published by Elsevier Ltd.

  7. Absorption mechanisms for cationic and anionic mineral species on ferric iron polymer hydroxides and oxidation products of ferrous iron in aqueous media

    International Nuclear Information System (INIS)

    Gandon, Remi

    1982-01-01

    Adsorbents obtained by hydrolysing the Fe 3+ , 6H 2 O ion are made of polymers with aquo (H 2 O), hydroxo (-OH...) and oxo (...O...) ligands. Radioactive tracers reveal the importance of chemical mechanisms in adsorption phenomena on ferric oxide in aqueous media. Zn 2+ , Co 2+ and Mn 2+ cations are exchanged with hydrogen from hydroxo groups. CrO 4 2- , SeO 3 2- and Sb(OH) 6 - anions form covalent associations in place of iron ligands. The adsorption of hydrolyzed ions results in strong oxygen bridge bonds. In fresh water, Co and Mn participate alone in physical electrostatic adsorption. Iron II oxidation products generate chemical adsorptions. Zn 2+ and Sb(OH) 6 - associate with ferric hydroxides from oxidized Fe 2+ . 60 Co, 54 Mn and 51 Cr form covalent associations between unpaired 3d iron electrons and the adsorbed element. This process is not predominant with selenium IV or VI reduced to the metallic state or fixed on ferric hydroxide in the selenite form. These conclusions can be applied to pollutant analysis and to water purification and contribute to our understanding of the role of iron in the distribution of oligo-elements in aqueous media. (author) [fr

  8. Variations of 57Fe hyperfine parameters in medicaments containing ferrous fumarate and ferrous sulfate

    International Nuclear Information System (INIS)

    Oshtrakh, M. I.; Novikov, E. G.; Dubiel, S. M.; Semionkin, V. A.

    2010-01-01

    Several commercially available medicaments containing ferrous fumarate (FeC 4 H 2 O 4 ) and ferrous sulfate (FeSO 4 ), as a source of ferrous iron, were studied using a high velocity resolution Mössbauer spectroscopy. A comparison of the 57 Fe hyperfine parameters revealed small variations for the main components in both medicaments indicating some differences in the ferrous fumarates and ferrous sulfates. It was also found that all spectra contained additional minor components probably related to ferrous and ferric impurities or to partially modified main components.

  9. Variations of {sup 57}Fe hyperfine parameters in medicaments containing ferrous fumarate and ferrous sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Oshtrakh, M. I., E-mail: oshtrakh@mail.utnet.ru; Novikov, E. G. [Ural Federal University (The former Ural State Technical University-UPI), Faculty of Physical Techniques and Devices for Quality Control (Russian Federation); Dubiel, S. M. [AGH University of Science and Technology, Faculty of Physics and Computer Science (Poland); Semionkin, V. A. [Ural Federal University (The former Ural State Technical University-UPI), Faculty of Physical Techniques and Devices for Quality Control (Russian Federation)

    2010-04-15

    Several commercially available medicaments containing ferrous fumarate (FeC{sub 4}H{sub 2}O{sub 4}) and ferrous sulfate (FeSO{sub 4}), as a source of ferrous iron, were studied using a high velocity resolution Moessbauer spectroscopy. A comparison of the {sup 57}Fe hyperfine parameters revealed small variations for the main components in both medicaments indicating some differences in the ferrous fumarates and ferrous sulfates. It was also found that all spectra contained additional minor components probably related to ferrous and ferric impurities or to partially modified main components.

  10. Removal of chlorite by reaction with ferrous iron

    OpenAIRE

    Iatrou, Angela

    1991-01-01

    The use of chlorine dioxide as an oxidant and/or disinfectant for drinking water treatment has been an alternative considered when utilities seek to control trihalomethane concentrations. However, concern regarding residual concentrations of chlorite and chlorate have resulted in limitations on applied chlorine dioxide dosages. This study describes the use of ferrous iron as a possible reducing agent for the elimination of residual chlorite from drinking water.

  11. Evaluation of effects of Maṇḍurabhasma on structural and functional integrity of small intestine in comparison with ferrous sulfate using an experimental model of iron deficiency anemia

    Directory of Open Access Journals (Sweden)

    Suchita Rajanikant Gawde

    2015-01-01

    Conclusion: Rats receiving a high dose of MB have shown improvement in hematinic and lactase levels comparable to those receiving ferrous sulfate. However, it causes lesser oxidative damage as compared to ferrous sulfate. This is an encouraging finding because it indicates the potential of MB to cause lesser gastrointestinal side effects compared to ferrous sulfate.

  12. Ferrous sulphate interacts with captopril

    Science.gov (United States)

    Schaefer, J P; Tam, Y; Hasinoff, B B; Tawfik, S; Peng, Y; Reimche, L; Campbell, N R C

    1998-01-01

    Aims To determine if iron binds strongly to captopril and reduces captopril absorption. Methods A variety of in vitro experiments was conducted to examine iron binding to captopril and a randomized, double-blind, placebo controlled, cross-over study design was used to assess the in vivo interaction. Captopril (25 mg) was coingested with either ferrous sulphate (300 mg) or placebo by seven healthy adult volunteers. Subjects were phlebotomized and had blood pressure measured at 0, 0.25, 0.5, 1, 2, 4, 6, 8, and 12 h post ingestion. A 1 week washout period was used. Results The coingestion of ferrous sulphate and captopril was associated with a 37% (134 ng ml−1 h, 95% CI 41–228 ng ml−1 h, P=0.03) decrease in area under the curve (AUC) for unconjugated plasma captopril. There were no substantial changes in Cmax (mean difference;–32; 95% CI −124–62 ng ml−1(P=0.57)) or in tmax (mean difference; 0; 95% CI −18–18 min (P=0.65)) for unconjugated captopril when captopril was ingested with iron. There was a statistically insignificant increase in AUC for total plasma captopril of 43% (1312 ng ml−1 h, 95% CI −827–3451 ng ml−1 h P=0.27) when captopril was ingested with iron. The addition of ferric chloride to captopril resulted in the initial rapid formation of a soluble blue complex which rapidly disappeared to be replaced by a white precipitant. The white precipitate was identified as captopril disulphide dimer. There were no significant differences in systolic and diastolic blood pressures between the treatment and placebo groups. Conclusions Co-administration of ferrous sulphate and iron results in decreased unconjugated captopril levels likely due to a chemical interaction between ferric ion and captopril in the gastrointestinal tract. Care is required when coprescribing captopril and iron salts. PMID:9803987

  13. Effect of ferrous metal presence on lead leaching in municipal waste incineration bottom ashes.

    Science.gov (United States)

    Oehmig, Wesley N; Roessler, Justin G; Zhang, Jianye; Townsend, Timothy G

    2015-01-01

    The recovery of ferrous and non-ferrous metals from waste to energy (WTE) ash continues to advance as the sale of removed metals improves the economics of waste combustion. Published literature suggests that Fe and Fe oxides play a role in suppressing Pb leaching in the Toxicity Characteristic Leaching Procedure (TCLP); further removal of ferrous metals from WTE ashes may facilitate higher Pb leaching under the TCLP. Eight WTE bottom ash size-fractions, from three facilities, were evaluated to assess the effect of metallic Fe addition and ferrous metal removal on TCLP leaching. Metallic Fe addition was demonstrated to reduce Pb leaching; the removal of ferrous metals by magnet resulted in a decrease in total available Pb (mg/kg) in most ash samples, yet Pb leachability increased in 5 of 6 ash samples. The research points to two chemical mechanisms to explain these results: redox interactions between Pb and Fe and the sorption of soluble Pb onto Fe oxide surfaces, as well as the effect of the leachate pH before and after metals recovery. The findings presented here indicate that generators, processors, and regulators of ash should be aware of the impact ferrous metal removal may have on Pb leaching, as a substantial increase in leaching may have significant implications regarding the management of WTE ashes. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Ferrous iron transport in Streptococcus mutans

    Energy Technology Data Exchange (ETDEWEB)

    Evans, S.L.; Arcenaeux, J.E.L.; Byers, B.R.; Martin, M.E.; Aranha, H.

    1986-12-01

    Radioiron uptake from /sup 59/FeCl/sub 3/ by Streptococcus mutans OMZ176 was increased by anaerobiosis, sodium ascorbate, and phenazine methosulfate (PMS), although there was a 10-min lag before PMS stimulation was evident. The reductant ascorbate may have provided ferrous iron. The PMS was reduced by the cells, and the reduced PMS then may have generated ferrous iron for transport; reduced PMS also may have depleted dissolved oxygen. It was concluded that S. mutans transports only ferrous iron, utilizing reductants furnished by glucose metabolism to reduce iron prior to its uptake.

  15. Iron in ferrous gluconate and Ascofer (registered)

    Energy Technology Data Exchange (ETDEWEB)

    Gozdyra, R; Dubiel, S M; Cieslak, J, E-mail: dubiel@novell.ftj.agh.edu.p [Faculty of Physics and Computer Science, AGH University of Science and Technology, al. A. Mickiewicza 30, PL-30-059 Krakow (Poland)

    2010-03-01

    Ferrous gluconate and antianemic medicament Ascofer (registered) were investigated with Moessbauer spectroscopy in order to determine forms of iron ions present in both types of samples. Room temperature spectra gave a clear evidence that two phases of iron were present viz. ferrous (Fe{sup 2+}) as a major one with a contribution of {approx}85 {+-}5 %, and ferric (Fe{sup 3+}) whose contribution was found to be {approx}15{+-}5 %. Ferrous ions were shown to occupy at least two different sites.

  16. Adsorption of ferrous ions onto montmorillonites

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Dawei, E-mail: qdw109@163.com [Qilu University of Technology, Jinan, 250353, Shandong (China); Niu, Xia [Qilu University of Technology, Jinan, 250353, Shandong (China); Qiao, Min; Liu, Gang; Li, Hongxin; Meng, Zhenxiao [Shandong SiBang pharmaceutical co., LTD, Jinan, Shandong, 250200 (China)

    2015-04-01

    Highlights: • Adsorption study of ferrous ions on montmorillonites. • Using ascorbic acid as antioxidants in adsorption process. • Fe (II)-MMT had good affinity for phosphate. - Abstract: The adsorption of Fe (II) onto montmorillonites was investigated through initial concentration, contact time, pH and temperature. During the whole adsorption process, the ascorbic acid (Vitamin C) was added as a kind of antioxidant, at the same time, deionized water (after boiling) and nitrogen protection were also used to avoid oxidation. The Fe{sup 2+}/Fe{sub total} ratio of the iron exists in the Fe-montmorillonites was found more than 95%. Two kinetic models, including pseudo-first-order and pseudo-second-order model, were used to analyze the adsorption process of Fe (II) on montmorillonites. The results of our study showed that adsorption process fitted with pseudo-second-order well. Adsorption isotherms showed that Langmuir model was better than Freundlich model. The thermodynamic parameters ΔG{sup 0} and ΔH{sup 0} were 3.696 kJ/mol and 6.689 kJ/mol (we just gave the values at 298 K), respectively. The positive values at different temperatures showed that the adsorption process was non-spontaneous and endothermic. The characteristics of materials were determined by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Surface area and porosity analyzer, Thermogravimetric analysis (TGA), Differential scanning calorimeter (DSC) and Zeta potential distribution.

  17. Hydrometallurgical-UV process to produce ferrous sulfate from the pyrite present in coal tailings

    Energy Technology Data Exchange (ETDEWEB)

    Viganico, E.M.; Silva, R.A. [South Rio Grande Federal Univ., Porto Alegre (Brazil).Graduate Program in Mining, Metallurgical and Materials Technology Center

    2010-07-01

    The oxidation of pyrite can promote acid mine drainage (AMD). This study developed a hydrometallurgical-UV route for the production of ferrous sulfate. The laboratory study was conducted using a pyrite concentrate obtained from a processed coal tailing. Leaching of the tailing was performed in packed bed columns in an oxidizing environment with an aqueous medium. Recirculation of the liquor produced an Fe{sup 3+} iron rich extract. Ultraviolet irradiation was then used to convert the Fe{sup 3+} to Fe{sup 2+}. Heat provided by the UV lamps caused the ferrous sulfate to crystallize. X-ray diffraction (XRD) studies of the crystals demonstrated that it is possible to produce commercial-grade ferrous sulfate heptahydrate crystals from the pyrite present in coal tailings. The crystals are used to treat anemia in humans and animals, and are also used as reagents for waste and waste water treatment. 7 refs., 2 tabs., 2 figs.

  18. Fast and effective analysis of ferrous and non-ferrous alloys by X-ray fluorescence

    International Nuclear Information System (INIS)

    Gomez Serra, Abelardo

    1987-01-01

    An empirical method for the integral analysis of any kind of alloys, ferrous and non-ferrous, is described. The method is based on the intensities relation of the mixed elements and is independent of the size, shape and presentation of the sample. By this procedure, alloys with iron, copper, aluminium or magnesium base can be fastly classified. (S.M.) [es

  19. Effect of ferrous/ferric ions molar ratio on reaction mechanism for ...

    Indian Academy of Sciences (India)

    Magnetite nanoparticles were prepared by hydrothermal synthesis under various initial ferrous/ferric molar ratios without adding any oxidizing and reducing agents in order to clarify effects of the molar ratio on the reaction mechanism for the formation of magnetite nanoparticles. The magnetite nanoparticles prepared were ...

  20. Effects of ferrous ions on the reductive dechlorination of trichloroethylene by zero-valent iron

    International Nuclear Information System (INIS)

    Liu, C.-C.; Tseng, D.-H.; Wang, C.-Y.

    2006-01-01

    The surface characteristics of zero-valent iron (ZVI) and the efficiency of reductive dechlorination of trichloroethylene (TCE) in the presence of ferrous ions were studied. The experimental results indicated that the acid-washing of a metallic iron sample enhanced the efficiency of TCE degradation by ZVI. This occurred because acid-washing changed the conformation of oxides on the surface of iron from maghemite (γ-Fe 2 O 3 ) to the more hydrated goethite (α-FeOOH), as was confirmed by XPS analysis. However, when ferrous ions were simultaneous with TCE in water, the TCE degradation rate decreased as the concentration of ferrous ion increased. This was due to the formation of passive precipitates of ferrous hydroxide, including maghemite and magnetite (Fe 3 O 4 ), that coated on the surface of acid-washed ZVI, which as a result inhibited the electron transfer and catalytic hydrogenation mechanisms. On the other hand, in an Fe 0 -TCE system without the acid-washing pretreatment of ZVI, ferrous ions were adsorbed into the maghemite lattice which was then converted to semiconductive magnetite. Thus, the electrons were transferred from the iron surface and passed through the precipitates, allowing for the reductive dechlorination of TCE

  1. Multifactorial study and kinetics of signal development in ferrous-methylthymol blue-gelatin gel dosimeters.

    Science.gov (United States)

    Penev, Kalin I; Mequanint, Kibret

    2017-05-01

    To develop and characterize a ferrous-methylthymol blue-gelatin gel dosimeter with low optical background and appropriate additives for reduced rate of auto-oxidation and diffusion. A mixed-level multifactorial design of experiments was used to test the effects of the concentrations of sulfuric acid, 5-nitro-1,10-phenanthroline (Nn), and glyoxal (Gx) on the background absorbance, dose sensitivity, and auto-oxidation of the tested gel dosimeter. The dosimetric properties of the proposed ferrous-methylthymol blue-gelatin dosimeter, doped with Nn and Gx, were compared with the undoped formulation and with ferrous-xylenol orange-gelatin gel dosimeters. Irradiations were performed in both small-scale cuvette samples and large 400-mL bulk samples. In addition to that, a new kinetic model for the signal development postirradiation was derived based on chemical principles and used for comparison of the different formulations. The new formulation showed a reduced auto-oxidation rate, while maintaining low background absorbance relative to the common ferrous-xylenol orange-gelatin gel dosimeter. Compared with undoped ferrous-xylenol orange or ferrous-methylthymol blue gels, the dose sensitivity of the new formulation is approximately 2 to 3 times lower, but remains clinically adequate. A previously unreported dose rate dependence of the dose sensitivity was observed, and a new kinetic model for the signal development postirradiation was used to investigate this effect. Similar dose rate dependences in gels containing either methylthymol blue or xylenol orange, with or without doping with Nn and Gx, were observed, suggesting that the low ferrous ammonium sulfate concentrations used in studied formulations were responsible for this effect. A multifactorial design of experiments and a new kinetic model for the signal development postirradiation were successfully employed to optimize the composition and characterize the properties of a new ferrous-methylthymol blue-gelatin gel

  2. Bacterial ferrous iron transport: the Feo system.

    Science.gov (United States)

    Lau, Cheryl K Y; Krewulak, Karla D; Vogel, Hans J

    2016-03-01

    To maintain iron homeostasis within the cell, bacteria have evolved various types of iron acquisition systems. Ferric iron (Fe(3+)) is the dominant species in an oxygenated environment, while ferrous iron (Fe(2+)) is more abundant under anaerobic conditions or at low pH. For organisms that must combat oxygen limitation for their everyday survival, pathways for the uptake of ferrous iron are essential. Several bacterial ferrous iron transport systems have been described; however, only the Feo system appears to be widely distributed and is exclusively dedicated to the transport of iron. In recent years, many studies have explored the role of the FeoB and FeoA proteins in ferrous iron transport and their contribution toward bacterial virulence. The three-dimensional structures for the Feo proteins have recently been determined and provide insight into the molecular details of the transport system. A highly select group of bacteria also express the FeoC protein from the same operon. This review will provide a comprehensive look at the structural and functional aspects of the Feo system. In addition, bioinformatics analyses of the feo operon and the Feo proteins have been performed to complement our understanding of this ubiquitous bacterial uptake system, providing a new outlook for future studies. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Friction and wear of some ferrous-base metallic glasses

    Science.gov (United States)

    Miyoshi, K.; Buckley, D. H.

    1984-01-01

    Sliding friction experiments, X-ray photoelectron spectroscopy (XPS) analysis, and electron microscopy and diffraction studies were conducted with ferrous base metallic glasses (amorphous alloys) in contact with aluminium oxide at temperatures to 750 C in a vacuum. Sliding friction experiments were also conducted in argon and air atmospheres. The results of the investigation indicate that the coefficient of friction increases with increasing temperature to 350 C in vacuum. The increase in friction is due to an increase in adhesion resulting from surface segregation of boric oxide and/or silicon oxide to the surface of the foil. Above 500 C the coefficient of friction decreased rapidly. The decrease correlates with the segregation of boron nitride to the surface. Contaminants can come from the bulk of the material to the surface upon heating and impart boric oxide and/or silicon oxide at 350 C and boron nitride above 500 C. The segregation of contaminants is responsible for the friction behavior. The amorphous alloys have superior wear resistance to crystalline 304 stainless steel. The relative concentrations of the various constituents at the surfaces of the amorphous alloys are very different from the nominal bulk compositions.

  4. Semi Automated Ferrous Material Scouring System (SAFMSS)

    Science.gov (United States)

    2016-03-14

    During normal activity, the operator needs to interrupt the operation periodically to dump the load of ferrous material. Once the operator...various targets used over the years including scraps from 55 gallon barrels, old cars and trucks as well as unidentifiable sources. Figure 8: Aerial...what the system uncovered the team surmised it was used mostly as a dump site for a mess hall. The Dona Ana range complex has been used by the army

  5. Experimental Investigation and Simulation of Ferrous Biooxidation and Flow Hydrodynamics in a Bubble Column Bioreactor Using CFD Approach

    Science.gov (United States)

    Mousavi, S. M.; Jafari, A.; Yaghmaei, S.; Vossoughi, M.; Turunen, I.

    2008-05-01

    In the present attempt a set of experiments and a 3D simulation using a commercially available computational fluid dynamics package (FLUENT) were adopted to investigate complex behavior involving hydrodynamics and ferrous biological oxidation in a gas-liquid bubble column reactor. By combining the hydrodynamics and chemical species transport equations, the velocity field, air volume fraction and ferrous biooxidation rate in the column were simulated. The kinetic model proposed by Nemati and Webb (1998) was used to simulate the biooxidation rate in the column. Gas-liquid interactions were modeled using an Eulerian model in three dimensions. The effects of inlet air velocity and initial substrate (Fe+2) concentration on the velocity field, air volume fraction and biooxidation rate of ferrous iron in the column were investigated. To validate the model, simulation was compared with the experimental data in the presence of Acidithiobacillus ferrooxidans in an aerated column where the superficial gas velocity was adjusted between 0 and 0.5 m/s. It was found that the initial ferrous concentration and the inlet air velocity had a pronounced effect on the ferrous biooxidation rate. The results indicated that the maximum biooxidation rate can be obtained at superficial air velocity of 0.1 m/s and initial ferrous concentration of 6.7 g/L.

  6. Passive Aerial Grasping of Ferrous Objects

    KAUST Repository

    Fiaz, Usman Amin

    2017-10-19

    Aerial transportation is probably the most efficient way to supply quick and effective aid especially in cases of emergency like search and rescue operations. Thus the ability to grasp and deliver objects is of vital importance in all sorts of unmanned and autonomous aerial operations. We detail a simple yet novel approach for aerial grasping of ferrous objects using a passive magnetic pickup and an impulse based drop mechanism. The design enables our gripper to grasp ferrous objects using single as well as multiple gripping pads, with visual as well as pickup and drop feedback. We describe the various components of the gripper with emphasis on its low mass and high lift capability since weight is a matter of high consideration in all aerial applications. In addition, we investigate and address the issues that may cause our design to fail. We demonstrate by experiments that the proposed design is robust and effective, based on its high payload capability, its sturdiness against possible slide during aggressive aerial maneuvers, and optimum performance of the drop mechanism for the designed range of payloads. We also show that the gripper is able to pick up and drop a single as well as multiple ferrous objects of different shapes, curvature, and inclination, which also involves picking up an object and then grasping the next, while keeping hold of the previous one.

  7. NON-FERROUS EXPORTS CONCENTRATION AND GLOBAL INVESTMENTS

    OpenAIRE

    Brîndușa COVACI

    2016-01-01

    In the context of high-tech and telecommunication, non-ferrous sector has a crucial role in industries development. Cooper, nickel, aluminum, zinc, lead and tin are used, directly or indirectly, in most of the technologies, especially in high-tech production. The paper present a short index of the global investments for the non-ferrous transnational corporations listed on London Metal Exchange. The non-ferrous investment index presented in the paper refers to the most profitable corporation e...

  8. Development of cast ferrous alloys for Stirling engine application

    International Nuclear Information System (INIS)

    Lemkey, F.D.

    1982-01-01

    Low cost cast ferrous base alloys that can be used for cylinder and regenerator housing components of the Stirling engine were investigated. The alloys must meet the requirements of high strength and thermal fatigue resistance to approximately 1500 F, compatibility and low permeability with hydrogen, good elevated temperature oxidation/corrosion resistance, and contain a minimum of strategic elements. The phase constituents of over twenty alloy iterations were examined by X-ray diffraction. These alloy candidates were further screened for their tensile and stress rupture strength and surface stability in air at 1450 and 1600 F, respectively. Two alloys, NASAUT 1G (Fe-10Mn-20Cr-1.5C-1.0Si) and NASAUT 4G (Fe-15Mn-12Cr-3Mo-1.5C-1.0Si-1.0Nb), were chosen for more extensive elevated temperature testing. These alloys were found to exhibit nearly equivalent elevated temperature creep strength and oxidation resistance. Silicon present in these alloys at the 1 w/o level permitted the achievement of oxide scale adherence to 1600 F without loss of strength (or ductility) as was noted for equivalent additions of aluminum

  9. Thermally activated martensite formation in ferrous alloys

    DEFF Research Database (Denmark)

    Villa, Matteo; Somers, Marcel A. J.

    2017-01-01

    Magnetometry was applied to investigate the formation of α/α´martensite in 13ferrous alloys during immersion in boiling nitrogen and during re-heating to room temperature at controlled heating rates in the range 0.0083-0.83 K s-1. Data showsthat in 3 of the alloys, those that form {5 5 7}γ...... martensite, no martensite developsduring cooling. For all investigated alloys, irrespective of the type of martensiteforming, thermally activated martensite develops during heating. The activationenergy for thermally activated martensite formation is in the range 8‒27 kJ mol-1and increases with the fraction...... of interstitial solutes in the alloy...

  10. Evaluation of iron transport from ferrous glycinate liposomes using ...

    African Journals Online (AJOL)

    2017-09-03

    Sep 3, 2017 ... the effects of liposomal carriers, phytic acid, zinc and particle size on iron transport using Caco-2 cell models. Methods: Caco-2 cells were .... port of ferrous glycinate liposomes could result from the protection of ferrous glycinate by ..... 1998;37:12875-12883. 23. Albanese A, Tang PS, Chan WC The effect of.

  11. NON-FERROUS EXPORTS CONCENTRATION AND GLOBAL INVESTMENTS

    Directory of Open Access Journals (Sweden)

    Brîndușa COVACI

    2016-12-01

    Full Text Available In the context of high-tech and telecommunication, non-ferrous sector has a crucial role in industries development. Cooper, nickel, aluminum, zinc, lead and tin are used, directly or indirectly, in most of the technologies, especially in high-tech production. The paper present a short index of the global investments for the non-ferrous transnational corporations listed on London Metal Exchange. The non-ferrous investment index presented in the paper refers to the most profitable corporation exports on world, European Union (EU28 and Central and Eastern Europe (CEE level. The export concentration, estimated through Herfindahl-Hirschmann index on world, EU28, CEE and Romanian level, show that the non-ferrous industry is in full process of releasing. The cases presented in the article show that the non-ferrous companies invest intensively in equipment and technologies with superior production capacities, which combat pollution given by non-ferrous processes, research and development for the non-ferrous innovative technologies, and creating new markets. Sustainable and intelligent development is the inflexion point of the non-ferrous transnational corporation investments. The research is predominant in exploration of the transnational corporations’ internet pages and reports, and statistical calculus from international trade websites.

  12. New trends for non-ferrous metals in the electrical engineering industry

    International Nuclear Information System (INIS)

    Singer, R.F.

    1989-01-01

    The non-ferrous metals copper, aluminium and nickel are of major importance to the electrical engineering industry. Copper is used for magnet wire, underground cable and overhead contact wire, and aluminium is important for overhead power transmission lines. Nickel alloys are employed as gas turbine blades in power generation. An important new trend in the conductor area is rapid solidification for improved combinations of strength and conductivity. Another new trend is the Conform continuous extrusion process which can decrease cost and increase quality. New high temperature superconductors might change the conductor market completely, but only on the long run. Nickel base blading materials will see considerable improvements from oxide dispersion strengthening and directional solidification. In summary, non-ferrous materials technology for electrical engineering applications is on the move and considerable improvements can be expected within the next decade. (orig.) [de

  13. The physiological concentration of ferrous iron (II) alters the inhibitory effect of hydrogen peroxide on CD45, LAR and PTP1B phosphatases.

    Science.gov (United States)

    Kuban-Jankowska, Alicja; Gorska, Magdalena; Jaremko, Lukasz; Jaremko, Mariusz; Tuszynski, Jack A; Wozniak, Michal

    2015-12-01

    Hydrogen peroxide is an important regulator of protein tyrosine phosphatase activity via reversible oxidation. However, the role of iron in this reaction has not been yet elucidated. Here we compare the influence of hydrogen peroxide and the ferrous iron (reagent for Fenton reaction) on the enzymatic activity of recombinant CD45, LAR, PTP1B phosphatases and cellular CD45 in Jurkat cells. The obtained results show that ferrous iron (II) is potent inhibitor of CD45, LAR and PTP1B, but the inhibitory effect is concentration dependent. We found that the higher concentrations of ferrous iron (II) increase the inactivation of CD45, LAR and PTP1B phosphatase caused by hydrogen peroxide, but the addition of the physiological concentration (500 nM) of ferrous iron (II) has even a slightly preventive effect on the phosphatase activity against hydrogen peroxide.

  14. Possible Association of Ferrous Phosphates and Ferric Sulfates in S-rich Soil on Mars

    Science.gov (United States)

    Mao, J.; Schroeder, C.; Haderlein, S.

    2012-12-01

    NASA Mars Exploration Rover (MER) Spirit explored Gusev Crater to look for signs of ancient aqueous activity, assess past environmental conditions and suitability for life. Spirit excavated light-toned, S-rich soils at several locations. These are likely of hydrothermal, possibly fumarolic origin. At a location dubbed Paso Robles the light-toned soil was also rich in P - a signature from surrounding rock. While S is mainly bound in ferric hydrated sulfates [1], the mineralogy of P is ill-constrained [2]. P is a key element for life and its mineralogy constrains its availability. Ferrous phases observed in Paso Robles Mössbauer spectra may represent olivine and pyroxene from surrounding basaltic soil [1] or ferrous phosphate minerals [3]. Phosphate is well-known to complex and stabilize Fe 2+ against oxidation to Fe 3+ . Schröder et al. [3] proposed a formation pathway of ferrous phosphate/ferric sulfate associations: sulfuric acid reacts with basalt containing apatite, forming CaSO4 and phosphoric acid. The phosphoric and/or excess sulfuric acid reacts with olivine, forming Fe2+-phosphate and sulfate. The phosphate is less soluble and precipitates. Ferrous sulfate remains in solution and is oxidized as pH increases. To verify this pathway, we dissolved Fe2+-chloride and Na-phosphate salts in sulfuric acid inside an anoxic glovebox. The solution was titrated to pH 6 by adding NaOH when a first precipitate formed, which was ferrous phosphate according to Mössbauer spectroscopy (MB). At that point the solution was removed from the glovebox and allowed to evaporate in the presence of atmospheric oxygen, leading to the oxidation of Fe2+. The evaporation rate was controlled by keeping the suspensions at different temperatures; pH was monitored during the evaporation process. The final precipitates were analyzed by MB and X-Ray Fluorescence (XRF), comparable to MER MB and Alpha Particle X-ray Spectrometer instrument datasets, and complementary techniques such as X

  15. Application of tracer techniques and technical means in ferrous, non-ferrous and hydrometallurgy

    International Nuclear Information System (INIS)

    Chizhek, L.; Myshak, F.; Shtrba, J.

    1979-01-01

    Brief data are given about the results of joint investigations and developments of the problems of radioisotope methods and technical means application in ferrous and hydrometallurgy, obtained during the period of 1976-1977. Development of these problems was done in the frameworks of the plan of scientific and technical cooperation of the CMEA member-states and Yugoslavia. Results are given of the development of following themes: investigation of metallurgic processes by means of activation analysis; investidations of metallurgic processes by means of autoradiography and X-ray feuorescent analysis; control and automatization of metallurgic processes by means of radioisotope instruments; investigation of processes of melting of cast iron and steel as well as of processes of treatment of metals by means of the radioactive indicators method, activation analysis and radioisotope instruments; application of the radioisotope methods and technical means for investigation of processes of production of non-ferrous metals; application of the radioisotope methods for investigations of the hydrometallurgy processes [ru

  16. Sensory evaluation of dairy supplements enriched with reduced iron, ferrous sulfate or ferrous fumarate

    Directory of Open Access Journals (Sweden)

    Josefina C Morales

    2015-01-01

    Full Text Available Objective. To determine the degree of liking of the Oportunidades programme dietary supplements (DS –purees and beverages– added with different iron salts (IS: reduced iron (RI, ferrous sulphate (FS or ferrous fumarate (FF during 24 weeks of storage. Materials and methods. The DS were evaluated through a hedonic scale for aroma, flavour and colour attributes; at time zero and every eight weeks, each panel member evaluated three DS with same flavour and presentation but different IS. Seventy women participated as panel members. Results. The chocolate and banana DS exhibited a change in preference by colour and flavour due to storage. DS with FS or RI showed the least preference by flavour and colour in the context of the three IS considered. The chocolate and neutral DS enriched with FS changed their colour and flavour. Conclusion. DS were, in general, well-liked; nonetheless, for purees enriched with FS and for beverages enriched with RI, the less-liked attributes were colour and flavour

  17. Bacteria-assisted preparation of nano α-Fe2O3 red pigment powders from waste ferrous sulfate

    International Nuclear Information System (INIS)

    Li, Xiang; Wang, Chuankai; Zeng, Yu; Li, Panyu; Xie, Tonghui; Zhang, Yongkui

    2016-01-01

    Highlights: • A route to prepare nano α-Fe 2 O 3 red pigment from waste ferrous sulfate is proposed. • Acidithiobacillus ferrooxidans is introduced for accelerating iron oxidation. • The particle size of synthetic α-Fe 2 O 3 is ranged from 22 nm to 86 nm. • The prepared nano α-Fe 2 O 3 red pigment fulfills ISO 1248-2006. - Abstract: Massive ferrous sulfate with excess sulfuric acid is produced in titanium dioxide industry each year, ending up stockpiled or in landfills as solid waste, which is hazardous to environment and in urgent demand to be recycled. In this study, waste ferrous sulfate was used as a second raw material to synthesize nano α-Fe 2 O 3 red pigment powders with a bacteria-assisted oxidation process by Acidithiobacillus ferrooxidans. The synthesis route, mainly consisting of bio-oxidation, precipitation and calcination, was investigated by means of titration, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence (XRF) to obtain optimum conditions. Under the optimum conditions, nano α-Fe 2 O 3 red pigment powders contained 98.24 wt.% of Fe 2 O 3 were successfully prepared, with a morphology of spheroidal and particle size ranged from 22 nm to 86 nm and averaged at 45 nm. Moreover, the resulting product fulfilled ISO 1248-2006, the standards of iron oxide pigments.

  18. Friction and surface chemistry of some ferrous-base metallic glasses

    Science.gov (United States)

    Miyoshi, K.; Buckley, D. H.

    1982-01-01

    The friction properties of some ferrous-base metallic glasses were measured both in argon and in vacuum to a temperature of 350 C. The alloy surfaces were also analyzed with X-ray photoelectron spectroscopy to identify the compounds and elements present on the surface. The results of the investigation indicate that even when the surfaces of the amorphous alloys, or metallic glasses, are atomically clean, bulk contaminants such as boric oxide and silicon dioxide diffuse to the surfaces. Friction measurements in both argon and vacuum indicate that the alloys exhibit higher coefficients of friction in the crystalline state than they do in the amorphous state.

  19. Were mercury emission factors for Chinese non-ferrous metal smelters overestimated? Evidence from onsite measurements in six smelters

    International Nuclear Information System (INIS)

    Zhang Lei; Wang Shuxiao; Wu Qingru; Meng Yang; Yang Hai; Wang Fengyang; Hao Jiming

    2012-01-01

    Non-ferrous metal smelting takes up a large proportion of the anthropogenic mercury emission inventory in China. Zinc, lead and copper smelting are three leading sources. Onsite measurements of mercury emissions were conducted for six smelters. The mercury emission factors were 0.09–2.98 g Hg/t metal produced. Acid plants with the double-conversion double-absorption process had mercury removal efficiency of over 99%. In the flue gas after acid plants, 45–88% was oxidized mercury which can be easily scavenged in the flue gas scrubber. 70–97% of the mercury was removed from the flue gas to the waste water and 1–17% to the sulfuric acid product. Totally 0.3–13.5% of the mercury in the metal concentrate was emitted to the atmosphere. Therefore, acid plants in non-ferrous metal smelters have significant co-benefit on mercury removal, and the mercury emission factors from Chinese non-ferrous metal smelters were probably overestimated in previous studies. - Highlights: ► Acid plants in smelters provide significant co-benefits for mercury removal (over 99%). ► Most of the mercury in metal concentrates for smelting ended up in waste water. ► Previously published emission factors for Chinese metal smelters were probably overestimated. - Acid plants in smelters have high mercury removal efficiency, and thus mercury emission factors for Chinese non-ferrous metal smelters were probably overestimated.

  20. Analyses of Ferrous and Ferric State in DynabiTab Using Mössbauer Spectroscopy

    Directory of Open Access Journals (Sweden)

    Young Rang Uhm

    2017-01-01

    Full Text Available Antianemic medicament ferrous gluconate, ferrous fumarate, and a Dynabi tablet with a basic iron bearing ingredient were studied with the use of Mössbauer spectroscopy. Room temperature spectra of ferrous gluconate gave clear evidence that the two phases of iron were present: ferrous (Fe2+ as a major one with a contribution at and above 91 a.u.% and ferric (Fe3+ whose contribution was found to be ~9 a.u.%. In the case of ferrous fumarate, a single phase was measured corresponding to ferrous (Fe2+ state. A Dynabi tablet consists of ferrous fumarate and ferrous fumarate. The ferric phase in ferrous gluconate is able to be reached about ~3.6 a.u.% in a tablet.

  1. ABOUT HEAT TREATMENTS APPLIED TO FERROUS ALLOYS AND METALS

    Directory of Open Access Journals (Sweden)

    Alin Stancioiu

    2016-05-01

    Full Text Available Materials and non-ferrous alloys lends itself through more plastic deformation processes. It is known that after deformation the material structure, as well as properties that are no longer adequate therefore is applied recrystallization annealing for the purpose of restore the initial structure. To increase the hardness of non-ferrous alloys it must after hardening the cooling rate to be slow. This is explained by the fact that of chemical compounds give time to precipitate on the edge of grain to the base of the constituents of alloys.

  2. A quantitative description of the action of high-dose pulses of radiation on aerated acid solutions containing ferrous and chloride ions

    International Nuclear Information System (INIS)

    Bjergbakke, E.; Navaratnam, S.; Parsons, B.J.; Swallow, A.J.

    1987-01-01

    Kinetic measurements of the production of ferric complexes have been made for up to 100 s following a 1 μs pulse of 10 MeV electrons (165 kGy) given to aerated, acid solutions containing ferrous and chloride ions. The yields of ferric ions have been quantitatively accounted for by computations involving a scheme with 34 reactions. The rate constants necessary for a good fit are consistent with published values except for the oxidation of ferrous ions by chlorine atoms for which we now propose a value of 1.3 x 10 10 dm 3 mol -1 s -1 . (author)

  3. Protonation of Ferrous Dinitrogen Complexes Containing a Diphosphine Ligand with a Pendant Amine

    Energy Technology Data Exchange (ETDEWEB)

    Heiden, Zachariah M.; Chen, Shentan; Mock, Michael T.; Dougherty, William G.; Kassel, W. S.; Rousseau, Roger J.; Bullock, R. Morris

    2013-04-01

    The addition of protons to pendant amine containing ferrous dinitrogen complexes, of the type [FeX(N2)(PEtNMePEt)(dmpm)]+ (X = H, Cl, or Br; PEtNMePEt = Et2PCH2N(Me)CH2PEt2 and dmpm = Me2PCH2PMe2), was found to protonate at the pendant amine as opposed to the dinitrogen ligand. This protonation increased the νN2 of the complex by about 25 cm-1, shifting the Fe(II/I) couple 330 mV to a more positive potential. A similar shift was observed in the case of [FeX(CO)(PEtNMePEt)(dmpm)]+ (X = H, Cl, or Br). Computational analysis verified these experimental results and showed the coordination of N2 to Fe(II) centers increases the basicity of N2 (vs. free N2) by 13 and 20 pKa units for the trans halides and hydrides, respectively. Although the iron center was found to increase the basicity of the bound N2 ligand, coordinated N2 is not sufficiently basic to be protonated. In the case of ferrous dinitrogen complexes containing a basic pendant methylamine, the amine site was determined to be the most basic site by 30 pKa units compared to protonation at the N2 ligand. To increase the basicity of the N2 ligand in order to promote proton transfer from the pendant amine to the N2 ligand, chemical reduction of these ferrous dinitrogen complexes was performed and found to result in oxidative addition of the methylene C-H bond of the PEtNMePEt ligand to Fe, preventing isolation of a reduced Fe(0) N2 complex. This work was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences.

  4. The ferrous ammonium sulfate solid system, as dosemeter for processes at low temperatures and high doses of gamma radiation

    International Nuclear Information System (INIS)

    Juarez C, J.M.; Ramos B, S.; Negron M, A.

    2005-01-01

    This paper presents the results obtained from a study of the radiation induced oxidation of crystalline ferrous ammonium sulfate with gamma rays at 295 K, 263 K and 77 K and dose from 0 to 300 kGy. The radiation induced decomposition of ferrous ammonium sulfate has been studied by the dissolution of the irradiated salt in 0,8 N sulfuric acid. The main product is Fe 3+ and molar concentration of ferric ion was determined spectrophotometrically in the UV region at 304 nm. The optical density values showed a linear dependence with dose, indicating that the data obtained might be used to create a calibrating curve. Color in irradiated salt changes from blue to green, yellow and orange according to the absorbed dose. The accuracy and the reproducibility of the system were tested. In addition, some other characteristics make possible the use of this system as a dosimeter, similar to Fricke chemical dosemeter, at low temperatures and high dose. (Author)

  5. Ion implanting ferrous metals to improve corrosion resistance

    International Nuclear Information System (INIS)

    Dearnaley, G.; Goode, P.D.

    1981-01-01

    A process is described for the treatment of a surface of a ferrous article to improve its corrosion resistance, wherein the surface is subjected to ion bombardment at a temperature above one hundred degrees centigrade in an evacuated enclosure which contains a residual quantity of gaseous oxygen. (author)

  6. Evaluation of iron transport from ferrous glycinate liposomes using ...

    African Journals Online (AJOL)

    Background: Iron fortification of foods is currently a strategy employed to fight iron deficiency in countries. Liposomes were assumed to be a potential carrier of iron supplements. Objective: The objective of this study was to investigate the iron transport from ferrous glycinate liposomes, and to estimate the effects of liposomal ...

  7. Lithium compatibility research: status and requirements for ferrous materials

    International Nuclear Information System (INIS)

    Selle, J.E.; Olson, D.L.

    1978-01-01

    A brief historical review and a description of the present status of the knowledge accumulated on lithium-ferrous alloy corrosion research are presented and discussed. The effects of various parameters are discussed and the future requirements of lithium corrosion research are presented and discussed

  8. Radiation dose distribution measured in hydrogels containing ferrous ions

    International Nuclear Information System (INIS)

    Jin Tao; Murat, A.Q.; Liu Shilian; Duan Shengrong

    1990-01-01

    By the aid of nuclear magnetic resonance and dual wavelength TLC scanner, the absorbed dose distribution in hydrogels containing ferrous sulfate has been measured. The result shows a good straight line between the proton longitudinal relaxation rate and absorbed dose up to 16 Gy in agarose gels. It appeared that thin layer of acrylamide is much better than film for obtaining smooth dose curves

  9. 46 CFR 148.04-13 - Ferrous metal borings, shavings, turnings, or cuttings (excluding stainless steel).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ferrous metal borings, shavings, turnings, or cuttings... Requirements for Certain Material § 148.04-13 Ferrous metal borings, shavings, turnings, or cuttings (excluding... described as ferrous metal borings, shavings, turnings, or cuttings on board vessels (excluding stainless...

  10. Solid ferrous ammonium sulfate as a dosimeter at low temperatures and high doses

    International Nuclear Information System (INIS)

    Juarez-calderon, J.M.; Ramos B, S.; Negron M, A.

    2006-01-01

    This paper presents the results obtained from a study of the radiation induced oxidation of crystalline ferrous ammonium sulfate with gamma rays at 295 K, 263 K and 77 K and doses from 0 to 300 kGy. The radiation induced decomposition of ferrous ammonium sulfate has been studied by the dissolution of the irradiated salt in 0,8 N sulfuric acid. The main product is ferric ion (Fe 3+ ) and its molar concentration was determined spectrophotometrically in the UV region at 304 nm. The optical density values showed a linear dependence with dose, indicating that the data obtained might be used to create a calibrating curve. Color in irradiated salt changes from blue to green, yellow and orange according to the absorbed dose. The accuracy and the reproducibility of the system were tested. In addition, some other characteristics make possible the use of this system as a dosimeter, similar to Fricke chemical dosimeter, for studies and works at low temperatures and high doses. (authors)

  11. Solid ferrous ammonium sulfate as a dosimeter at low temperatures and high doses

    Energy Technology Data Exchange (ETDEWEB)

    Juarez-calderon, J.M.; Ramos B, S.; Negron M, A. [Mexico Univ. Nacional Autonoma, Instituto de Ciencias Nucleares (Mexico)

    2006-07-01

    This paper presents the results obtained from a study of the radiation induced oxidation of crystalline ferrous ammonium sulfate with gamma rays at 295 K, 263 K and 77 K and doses from 0 to 300 kGy. The radiation induced decomposition of ferrous ammonium sulfate has been studied by the dissolution of the irradiated salt in 0,8 N sulfuric acid. The main product is ferric ion (Fe{sup 3+}) and its molar concentration was determined spectrophotometrically in the UV region at 304 nm. The optical density values showed a linear dependence with dose, indicating that the data obtained might be used to create a calibrating curve. Color in irradiated salt changes from blue to green, yellow and orange according to the absorbed dose. The accuracy and the reproducibility of the system were tested. In addition, some other characteristics make possible the use of this system as a dosimeter, similar to Fricke chemical dosimeter, for studies and works at low temperatures and high doses. (authors)

  12. Preparation, physical characterization, and stability of Ferrous-Chitosan microcapsules using different iron sources

    Science.gov (United States)

    Handayani, Noer Abyor; Luthfansyah, M.; Krisanti, Elsa; Kartohardjono, Sutrasno; Mulia, Kamarza

    2017-11-01

    Dietary modification, supplementation and food fortification are common strategies to alleviate iron deficiencies. Fortification of food is an effective long-term approach to improve iron status of populations. Fortification by adding iron directly to food will cause sensory problems and decrease its bioavailability. The purpose of iron encapsulation is: (1) to improve iron bioavailability, by preventing oxidation and contact with inhibitors and competitors; and (2) to disguise the rancid aroma and flavor of iron. A microcapsule formulation of two suitable iron compounds (iron II fumarate and iron II gluconate) using chitosan as a biodegradable polymer will be very important. Freeze dryer was also used for completing the iron microencapsulation process. The main objective of the present study was to prepare and characterize the iron-chitosan microcapsules. Physical characterization, i.e. encapsulation efficiency, iron loading capacity, and SEM, were also discussed in this paper. The stability of microencapsulated iron under simulated gastrointestinal conditions was also investigated, as well. Both iron sources were highly encapsulated, ranging from 71.5% to 98.5%. Furthermore, the highest ferrous fumarate and ferrous gluconate loaded were 1.9% and 4.8%, respectively. About 1.04% to 9.17% and 45.17% to 75.19% of Fe II and total Fe, were released in simulated gastric fluid for two hours and in simulated intestinal fluid for six hours, respectively.

  13. Production of ferrous sulfate from residue from the iron mining

    International Nuclear Information System (INIS)

    Cardoso, K.A; Riella, H.G.; Abreu, E.F.; Carvalho, E.F. Urano de; Durazzo, M.

    2012-01-01

    This paper was developed from a residue obtained by processing iron ore exploited by the mining company Samarco S/A. The residue was characterized and the analyses showed that it contains about 70% of the mineral hematite (Fe 2 O 3 ) and also that some economically important products could be produced. One is the ferrous sulfate that can be used in pharmaceuticals and also that can be used in the treatment of iron deficiency anemia. The iron, in addition to is importance for the industrial production of steel and parts in general, also has great biological importance in all living beings. In order to produce ferrous sulfate from the byproduct in question, it was developed a obtaining route using metallic iron as hematite reductor and sulfuric acid to form the salt. (author)

  14. Ferrous alloys cast under high pressure gas atmosphere

    Directory of Open Access Journals (Sweden)

    Pirowski Z.

    2007-01-01

    Full Text Available The main objective of this paper is describing the essence of the process of introducing nitrogen to the melt of ferrous alloys by application of overpressure above the metal bath. The problem was discussed in terms of both theory (the thermodynamic aspects of the process and practice (the technical and technological aspects, safety of the furnace stand operation, and technique of conducting the melt. The novel technique of melting under high pressure of the gas atmosphere (up to 5 MPa has not been used so far in the domestic industry, mainly because of the lack of proper equipment satisfyng the requirements of safe operation. Owing to cooperation undertaken with a partner from Bulgaria, a more detailed investigation of this technology has become possible and melting of selected ferrous alloys was conducted under the gas atmosphere at a pressure of about 3,5 MPa.

  15. Ferrous bisglycinate 25 mg iron is as effective as ferrous sulfate 50 mg iron in the prophylaxis of iron deficiency and anemia during pregnancy in a randomized trial

    DEFF Research Database (Denmark)

    Milman, Nils; Jønsson, Lisbeth; Dyre, Pernille

    2014-01-01

    OBJECTIVE: To compare the effects of oral ferrous bisglycinate 25 mg iron/day vs. ferrous sulfate 50 mg iron/day in the prevention of iron deficiency (ID) and iron deficiency anemia (IDA) in pregnant women. Design: Randomized, double-blind, intention-to-treat study. Setting: Antenatal care clinic...

  16. Ulceration of the oral mucosa following direct contact with ferrous sulfate in elderly patients: a case report and a review of the French National Pharmacovigilance Database

    Directory of Open Access Journals (Sweden)

    Liabeuf S

    2014-04-01

    Full Text Available Sophie Liabeuf,1–3 Valérie Gras,1 Julien Moragny,1 Marie-Laure Laroche,4 Michel Andrejak1,3On behalf of the French National Network of Pharmacovigilance Centers1Regional Pharmacovigilance Center, Division of Clinical Pharmacology, Amiens University Medical Center and Jules Verne University of Picardy, Amiens, France; 2Clinical Research Centre, Clinical Pharmacology Division, Amiens University Medical Center and the Jules Verne University of Picardy, Amiens, France; 3INSERM U1088, Amiens, France; 4Regional Pharmacovigilance Center, Department of Pharmacology, Toxicology and Pharmacovigilance, Limoges University Medical Center, Limoges, FranceObjective: To report a series of cases of ulceration of the oral mucosa linked to direct contact with ferrous sulfate in elderly patients.Case summary: The first case report concerns the occurrence of widespread oral ulceration in an 87-year-old woman with Alzheimer’s disease. The ulceration extended from the side of the tongue to the floor of the mouth. No clear explanation was found and various local treatments were ineffective. Once it was realized that the ferrous sulfate tablets (given as an iron supplement were crushed prior to administration (due to the patient’s deglutition disorder, withdrawal of this treatment led to rapid resolution of the ulceration. Nine other cases of oral ulcerations associated with ferrous sulfate were identified in the French National Pharmacovigilance Database. All but one of the patients were over 80 years of age and the youngest patient (a 54-year-old had dysphagia associated with facial paralysis.Discussion: Only two other reports of oral ulceration due to ferrous sulfate have been published to date. Mucosal toxicity of ferrous sulfate (which is probably related to oxidative stress has previously been reported for the hypopharynx, the esophageal lumen, and (after inhalation of a tablet the tracheobronchial tree.Conclusion: The mucosal toxicity of ferrous

  17. Surface chemistry, microstructure and friction properties of some ferrous-base metallic glasses at temperatures to 750 C

    Science.gov (United States)

    Miyoshi, K.; Buckley, D. H.

    1982-01-01

    X-ray photoelectron spectroscopy analysis, transmission electron microscopy, diffraction studies, and sliding friction experiments were conducted with ferrous-base metallic glasses in sliding contact with aluminum oxide at temperatures from room to 750 C in a vacuum of 30 nPa. The results indicate that there is a significant temperature influence on the friction properties, surface chemistry, and microstructure of metallic glasses. The relative concentrations of the various constituents at the surface of the sputtered specimens were very different from the normal bulk compositions. Contaminants can come from the bulk of the material to the surface upon heating and impart boric oxide and silicon oxide at 350 C and boron nitride above 500 C. The coefficient of friction increased with increasing temperature to 350 C. Above 500 C the coefficient of friction decreased rapidly. The segregation of contaminants may be responsible for the friction behavior.

  18. Active removal of ibuprofen by Money plant enhanced by ferrous ions.

    Science.gov (United States)

    Chehrenegar, Behdad; Hu, Jiangyong; Ong, Say Leong

    2016-02-01

    In this study, the removal of ibuprofen (IBP), a pharmaceutical compound, from aqueous media by Money plant (Epipremnum aureum) was investigated. The effect of ferrous iron (Fe(2+)) on enhancing the IBP removal rate was also analyzed. The first-order removal rate constants showed higher values for lower IBP initial concentrations in the range of 0.20-0.28 d(-1) for an initial concentration of 125 μg L(-1) to 0.03-0.13 d(-1) for an initial concentration of 1000 μg L(-1). Introducing ferrous iron to the aqueous media enhanced the first-order removal rate constant up to 6.5 times in a 3 d time period. Along with the removal of IBP from the media, the endogenous concentration of H2O2 also decreased presumably by the production of hydroxyl radical (·OH). Reduction in the endogenous H2O2 concentration was recorded to be 38% and 98% in the absence and presence of Fe(2+) respectively in the first day and the H2O2 level remained considerably low until day 7 which then gradually increased slightly. Simultaneous reduction of IBP and endogenous H2O2 concentration could be due to the reaction of IBP with ·OH and presumably ·OH production itself accelerated via Fenton reaction. In addition, presence of sodium bicarbonate (NaHCO3) as ·OH scavenger in the system showed reduction of first-order removal rate constant from 1.30 d(-1) to 0.07 d(-1) which could be a possible evidence of biological advanced oxidation process which is believed to play an important role in phytoremediation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Magnetic Resonance Imaging Dosimetry application to chemical ferrous gels

    International Nuclear Information System (INIS)

    Calmet, Ch.

    2000-10-01

    MRI dosimetry is based on the determination of relaxation parameters (T1, T2). Chemical detectors whose NMR properties are sensitive to irradiation are used. Difficulties in absolute relaxation times measure limit the use of this technique. The aim of this work first consists in the development of a quantitative method to determine T, relaxation time on irradiated ferrous gels. So, we can study processes and parameters which affect the technique sensibility. The method sensitivity first depends on imaging instrumentation. Quantitative MRI method used is able to eliminate variable imager factors. The study of instrumental parameters (coil, sequence parameters) permits to define an imaging protocol which is a function of the considered application (volume size, spatial resolution and accuracy). The method sensitivity depends on the detector sensibility too. The best composition of ferrous gel has been determined. Dose distributions are obtained in three minutes. Comparison between MRI results and conventional dosimetry methods (specially ionisation chamber and films) shows a deviation of about 5% for single irradiation with energy fields in the range of 300 keV to 25 MeV. So, the proposed method forms a suitable technique for 3D dosimetry. (author)

  20. Clean ferrous casting technology research. Final technical report, September 29, 1993--December 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Piwonka, T.S. [ed.

    1996-01-01

    This report details results of a 30-month program to develop methods of making clean ferrous castings, i.e., castings free of inclusions and surface defects. The program was divided into 3 tasks: techniques for producing clean steel castings, electromagnetic removal of inclusions from ferrous melts, and study of causes of metal penetration in sand molds in cast iron.

  1. Modified ferrous ammonium sulfate benzoic acid xyelenol orange (MFBX) and thermoluminescent dosimeters - a comparative study

    International Nuclear Information System (INIS)

    Brindha, S.; Rose, J.V.R.; Sathyan, S.; Singh, Rabi Raja I.; Ravindran, B. Paul

    2002-01-01

    Radiation dosimetry deals with the determination of absorbed dose to the medium exposed to ionizing radiation. Chemical dosimetry depends on oxidation or reduction of chemicals by ionizing radiation. A ferrous ammonium sulfate benzoic acid xyelenol orange (FBX) dosimeter based on this principle is being used as a clinical dosimeter at present. Certain modifications were carried out in the preparation and storage of the FBX dosimeter to increase its shelf life. The resulting dosimeter was called a modified FBX (MFBX) dosimeter and has been used in our department for the past few years. An extensive study of the dose, dose rate and energy response of the dosimeter was carried out and compared with a thermoluminescent (LiF 7 ) dosimeter. The results obtained were found to be comparable to the thermoluminescent (LiF 7 ) dosimeter. Hence it was concluded that the MFBX dosimeter could be used for phantom dosimetry, data collection and in vivo measurements. Easier preparation and availability of the reagents are added advantages of using MFBX as a clinical dosimeter in small radiotherapy departments. (author)

  2. Bacteria-assisted preparation of nano α-Fe{sub 2}O{sub 3} red pigment powders from waste ferrous sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiang; Wang, Chuankai; Zeng, Yu; Li, Panyu; Xie, Tonghui; Zhang, Yongkui, E-mail: zhangyongkui@scu.edu.cn

    2016-11-05

    Highlights: • A route to prepare nano α-Fe{sub 2}O{sub 3} red pigment from waste ferrous sulfate is proposed. • Acidithiobacillus ferrooxidans is introduced for accelerating iron oxidation. • The particle size of synthetic α-Fe{sub 2}O{sub 3} is ranged from 22 nm to 86 nm. • The prepared nano α-Fe{sub 2}O{sub 3} red pigment fulfills ISO 1248-2006. - Abstract: Massive ferrous sulfate with excess sulfuric acid is produced in titanium dioxide industry each year, ending up stockpiled or in landfills as solid waste, which is hazardous to environment and in urgent demand to be recycled. In this study, waste ferrous sulfate was used as a second raw material to synthesize nano α-Fe{sub 2}O{sub 3} red pigment powders with a bacteria-assisted oxidation process by Acidithiobacillus ferrooxidans. The synthesis route, mainly consisting of bio-oxidation, precipitation and calcination, was investigated by means of titration, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence (XRF) to obtain optimum conditions. Under the optimum conditions, nano α-Fe{sub 2}O{sub 3} red pigment powders contained 98.24 wt.% of Fe{sub 2}O{sub 3} were successfully prepared, with a morphology of spheroidal and particle size ranged from 22 nm to 86 nm and averaged at 45 nm. Moreover, the resulting product fulfilled ISO 1248-2006, the standards of iron oxide pigments.

  3. Measurement of dynamic wedge angles and beam profiles by means of MRI ferrous sulphate gel dosimetry

    Science.gov (United States)

    Bengtsson, Magnus; Furre, Torbjørn; Rødal, Jan; Skretting, Arne; Olsen, Dag R.

    1996-02-01

    The purpose of this study is to examine the possible value of measuring the dose distribution in dynamic wedge photon beams using ferrous sulphate gel phantoms analysed by MRI. The wedge angles and dose profiles were measured for a field size of and for dynamic wedge angles of , , and using a 15 MV photon beam generated from a Clinac 2100 CD (Varian). The dose profiles obtained from MRI ferrous sulphate gel were in good agreement with the dose measurements performed with a diode detector array. Also, the wedge angles determined from the MRI ferrous sulphate gel agreed well with the values obtained by using film dosimetry and with calculations by use of TMS (treatment planning system) (Helax, Uppsala, Sweden). The study demonstrated that MRI ferrous sulphate gel dosimetry is an adequate tool for measurements of some beam characteristics of dynamic radiation fields.

  4. Modeling of mechanical properties for ferrous shape memory alloy

    International Nuclear Information System (INIS)

    Wada, Manabu; Ide, Yusuke; Mizote, Shinichiro; Naoi, Hisashi; Tsukimori, Kazuyuki

    2002-08-01

    In order to acquire technical data that are necessary for manufacture and design of the simulation test device for analyzing the core mechanics of Fast Breeder Reactor, ferrous shape memory alloy of Fe-28%Mn-6%Si-5%Cr is melted, forged and heat-treated. The microstructures are austenite. The specimens are deformed of up to 16% work-strain by tensile and compressive test, resulting in appearance of epsilon-martensite that is induced by stress. Then, heating at 673K for 10 minutes causes austenitic transformation from epsilon-martensite and shape memory strains are measured. We also investigate shape memory character of specimens, which are given, so called 'training treatment' of 5% pre-strain and recovery heat treatment. As a result, there is little difference between tensile and compressive test without training treatment and shape memory strain is 2% after being given 5% work-strain and recovery heat treatment. On the other hand, training treatment is remarkable and shape memory strain reaches to 3.7% after 5% work-strain. We analyze shape recovery character of this alloy specimen at three-point bending by using finite element method, and indicate possibility that its deformation behavior can be estimated from mechanical properties' data obtained at tensile and compressive test. (author)

  5. Monodisperse ferrous phosphate colloids in an anoxic groundwater plume

    Science.gov (United States)

    Gschwend, Philip M.; Reynolds, Matthew D.

    1987-01-01

    Groundwater samples collected near a secondary-sewage infiltration site on Cape Cod, Massachusetts were examined for colloidal materials (10–1000 nm). In two wells the water contained a population of monodisperse 100-nm particles, detected using laser-light scattering and autocorrelation data processing. SEM and SEM-EDAX analysis of these colloidal materials collected on ultrafilters confirmed the laser light scattering result and revealed that these microparticles consisyed of primarily iron and phosphorus in a 1.86 Fe to 1.0 P stoichiometric ratio. Chemical analyses of the water samples, together with equilibrium solubility calculations, strongly suggest that the ion-activity product should exceed the solubility product of a 100-nm diameter predominantly vivianite-type (Fe3(PO4)2 · 8H2O) colloidal phase. In light of our results, we conclude that these microparticles were formed by sewage-derived phosphate combining with ferrous iron released from the aquifer solids, and that these colloids may be moving in the groundwater flow. Such a subsurface transport process could have major implications regarding the movement of particle-reactive pollutants traditionally viewed as non-mobile in groundwater.

  6. Titrimetric determination of uranium in low-grade ores by the ferrous ion-phosphoric acid reduction method

    International Nuclear Information System (INIS)

    Hitchen, A.; Zechanowitsch, G.

    1980-01-01

    The modification and extension of the U.S.A.E.C. ferrous ion-phosphoric acid reduction method for the determination of uranium in high-grade or relatively pure material to a method for the determination of uranium with a high accuracy and precision, in ores containing 0.004 to 7% U is described. It is simple, rapid and requires no prior separations from elements that, in other methods, frequently interfere. For sample materials having very high concentrations of interfering elements, a prior concentration step using extraction with tri-n-octylphosphine oxide is described, but it is shown that, for most low-grade ores, this step is unnecessary. (author)

  7. Effects of rapid, high-dose, elevated temperature ion implantation on the microstructure and tribology of ferrous surfaces

    Science.gov (United States)

    Williamson, D. L.; Wei, R.; Wilbur, P. J.

    1991-05-01

    High-current, broad-beam ion implantation at 60 keV using a relatively simple system produces elevated target temperatures and results in remarkable enhancements in the wear resistance of ferrous materials compared to lower implantation temperatures. Effects of N, C and O implantation into AISI 304 stainless steel at 200 and 400°C on the microstructure and tribology are evaluated by conversion electron Mössbauer spectroscopy, X-ray diffraction, and a specially designed pin-on-disc tribotester. C and N implantation at 400°C yields unusually thick layers of austenite containing high concentrations of C and N in interstitial solid solution thereby accounting for the enhanced mechanical properties. O implantation at 400°C results in Fe 2O 3-like oxide rather than O in solid solution so a dispersion strengthening of the surface layer is suggested.

  8. Telomerization of Vinyl Chloride with Chloroform Initiated by Ferrous Chloride-Dimethylacetamide under Ultrasonic Conditions

    Directory of Open Access Journals (Sweden)

    Hua Qian

    2015-01-01

    Full Text Available Telomerization of vinyl chloride with chloroform was investigated using ferrous chloride-dimethylacetamide system, and 42.1% yield, more than four times the one reported before, was achieved. The addition of ultrasound further improved the reaction and yield was raised to 51.9% with trace byproducts at highly reduced reaction time and temperature. Ferrous chloride-dimethylacetamide under ultrasonic irradiation acts as a very efficient catalyst system for the 1 : 1 telomerization.

  9. Changes in the Antioxidant Capacity and Iron-Binding Properties of Bovine Spermatozoa Following In Vitro Incubation with Ferrous or Ferric Iron

    Directory of Open Access Journals (Sweden)

    Eva Tvrdá

    2015-10-01

    Full Text Available The aim of this study was to assess the impact of ferrous (Fe2+ or ferric (Fe3+ iron on the antioxidant capacity and the ability to bind iron of bovine spermatozoa at specific time intervals (0h, 2h, 8h, 16h and 24h during an in vitro culture. 35 semen samples were collected from 7 adult breeding bulls and diluted in physiological saline solution supplemented with different concentrations (0, 1, 5, 10, 50, 100, 200, 500, 1000 μmol/L of FeCl2 or FeCl3. Spermatozoa motility was assessed using the SpermVisionTM CASA (Computer aided sperm analysis system. The ferric reducing ability of plasma (FRAP assay was applied to study the antioxidant capacity of the samples, while the ability of the sample to bind excess iron was determined using the Total iron-binding capacity (TIBC test. Both ferrous and ferric iron exhibited a dose- and time-dependent impact on the spermatozoa motility. Concentrations ≥50 µmol/L FeCl2 and ≥100 µmol/L FeCl3 led to a significant decrease of spermatozoa motion (P<0.001, while concentrations below 10 µmol/L FeCl2 and 50 µmol/L FeCl3 proved to preserve the parameter (P<0.001. The FRAP assay revealed that both ferrous as well as ferric iron had a similar effect on the FRAP marker of the samples: high concentrations led to a dramatic and significant (P<0.001 increase of the parameter, followed by a notable decrease of the reducing ability in the subsequent time periods, whose intensity was dependent upon the time, oxidation state of iron, as well as the time of analysis. Furthermore, supplementation of FeCl2 and FeCl3 had an impact on the capacity of the sperm culture to bind free iron, reflected in a significant decrease of the parameter (P<0.001 early on (Time 2h in case of high doses of both oxidative states of this biometal. In a direct comparison, ferrous iron has been shown to be more toxic than ferric iron.  Results from this in vitro study show that high concentrations of both forms of iron are toxic, while

  10. Degradation of bisphenol A in aqueous solution by persulfate activated with ferrous ion.

    Science.gov (United States)

    Jiang, Xiaoxuan; Wu, Yanlin; Wang, Peng; Li, Hongjing; Dong, Wenbo

    2013-07-01

    Degradation of bisphenol A (BPA) in aqueous solution was studied with high-efficiency sulfate radical (SO4(-·)), which was generated by the activation of persulfate (S2O8(2-)) with ferrous ion (Fe(2+)). S2O8(2-) was activated by Fe(2+) to produce SO4(-·), and iron powder (Fe(0)) was used as a slow-releasing source of dissolved Fe(2+). The major oxidation products of BPA were determined by liquid chromatography-mass spectrometer. The mineralization efficiency of BPA was monitored by total organic carbon (TOC) analyzer. BPA removal efficiency was improved by the increase of initial S2O8(2-) or Fe(2+) concentrations and then decreased with excess Fe(2+) concentration. The adding mode of Fe(2+) had significant impact on BPA degradation and mineralization. BPA removal rates increased from 49 to 97% with sequential addition of Fe(2+), while complete degradation was observed with continuous diffusion of Fe(2+), and the latter achieved higher TOC removal rate. When Fe(0) was employed as a slow-releasing source of dissolved Fe(2+), 100% of BPA degradation efficiency was achieved, and the highest removal rate of TOC (85%) was obtained within 2 h. In the Fe(0)-S2O8(2-) system, Fe(0) as the activator of S2O8(2-) could offer sustainable oxidation for BPA, and higher TOC removal rate was achieved. It was proved that Fe(0)-S2O8(2-) system has perspective for future works.

  11. Ferrous ammonium phosphate (FeNH₄PO₄) as a new food fortificant: iron bioavailability compared to ferrous sulfate and ferric pyrophosphate from an instant milk drink.

    Science.gov (United States)

    Walczyk, Thomas; Kastenmayer, Peter; Storcksdieck Genannt Bonsmann, Stefan; Zeder, Christophe; Grathwohl, Dominik; Hurrell, Richard F

    2013-06-01

    The main purpose of this study was to establish bioavailability data in humans for the new (Fe) fortification compound ferrous ammonium phosphate (FAP), which was specially developed for fortification of difficult-to-fortify foods where soluble Fe compounds cannot be used due to their negative impact on product stability. A double-blind, randomized clinical trial with cross-over design was conducted to obtain bioavailability data for FAP in humans. In this trial, Fe absorption from FAP-fortified full-cream milk powder was compared to that from ferric pyrophosphate (FPP) and ferrous sulfate. Fe absorption was determined in 38 young women using the erythrocyte incorporation dual stable isotope technique (⁵⁷Fe, ⁵⁸Fe). Geometric mean Fe absorption from ferrous sulfate, FAP and FPP was 10.4, 7.4 and 3.3 %, respectively. Fe from FAP was significantly better absorbed from milk than Fe from FPP (p soluble reference compound (p = 0.0002). Absorption ratios of FAP and FPP relative to ferrous sulfate as a measure of relative bioavailability were 0.71 and 0.32, respectively. The results of the present studies show that replacing FPP with FAP in full-cream milk could significantly improve iron bioavailability.

  12. Structure and catalytic activities of ferrous centers confined on the interface between carbon nanotubes and humic acid

    Science.gov (United States)

    Wang, Bing; Zhou, Xiaoyan; Wang, Dongqi; Yin, Jun-Jie; Chen, Hanqing; Gao, Xingfa; Zhang, Jing; Ibrahim, Kurash; Chai, Zhifang; Feng, Weiyue; Zhao, Yuliang

    2015-01-01

    Preparation of heterogeneous catalysts with active ferrous centers is of great significance for industrial and environmental catalytic processes. Nanostructured carbon materials (NCM), which possess free-flowing π electrons, can coordinate with transition metals, provide a confinement environment for catalysis, and act as potential supports or ligands to construct analogous complexes. However, designing such catalysts using NCM is still seldom studied to date. Herein, we synthesized a sandwich structured ternary complex via the coordination of Fe-loaded humic acid (HA) with C&z.dbd;C bonds in the aromatic rings of carbon nanotubes (CNTs), in which the O/N-Fe-C interface configuration provides the confinement environment for the ferrous sites. The experimental and theoretical results revealed octahedrally/tetrahedrally coordinated geometry at Fe centers, and the strong hybridization between CNT C π* and Fe 3d orbitals induces discretization of the atomic charges on aromatic rings of CNTs, which facilitates O2 adsorption and electron transfer from carbon to O2, which enhances O2 activation. The O2 activation by the novel HA/Fe-CNT complex can be applied in the oxidative degradation of phenol red (PR) and bisphenol A (BPA) in aqueous media.Preparation of heterogeneous catalysts with active ferrous centers is of great significance for industrial and environmental catalytic processes. Nanostructured carbon materials (NCM), which possess free-flowing π electrons, can coordinate with transition metals, provide a confinement environment for catalysis, and act as potential supports or ligands to construct analogous complexes. However, designing such catalysts using NCM is still seldom studied to date. Herein, we synthesized a sandwich structured ternary complex via the coordination of Fe-loaded humic acid (HA) with C&z.dbd;C bonds in the aromatic rings of carbon nanotubes (CNTs), in which the O/N-Fe-C interface configuration provides the confinement environment for the

  13. Reactions of Ferrous Coproheme Decarboxylase (HemQ) with O2 and H2O2 Yield Ferric Heme b.

    Science.gov (United States)

    Streit, Bennett R; Celis, Arianna I; Shisler, Krista; Rodgers, Kenton R; Lukat-Rodgers, Gudrun S; DuBois, Jennifer L

    2017-01-10

    A recently discovered pathway for the biosynthesis of heme b ends in an unusual reaction catalyzed by coproheme decarboxylase (HemQ), where the Fe(II)-containing coproheme acts as both substrate and cofactor. Because both O 2 and H 2 O 2 are available as cellular oxidants, pathways for the reaction involving either can be proposed. Analysis of reaction kinetics and products showed that, under aerobic conditions, the ferrous coproheme-decarboxylase complex is rapidly and selectively oxidized by O 2 to the ferric state. The subsequent second-order reaction between the ferric complex and H 2 O 2 is slow, pH-dependent, and further decelerated by D 2 O 2 (average kinetic isotope effect of 2.2). The observation of rapid reactivity with peracetic acid suggested the possible involvement of Compound I (ferryl porphyrin cation radical), consistent with coproheme and harderoheme reduction potentials in the range of heme proteins that heterolytically cleave H 2 O 2 . Resonance Raman spectroscopy nonetheless indicated a remarkably weak Fe-His interaction; how the active site structure may support heterolytic H 2 O 2 cleavage is therefore unclear. From a cellular perspective, the use of H 2 O 2 as an oxidant in a catalase-positive organism is intriguing, as is the unusual generation of heme b in the Fe(III) rather than Fe(II) state as the end product of heme synthesis.

  14. An apparent threshold dose response in ferrous xylenol-orange gel dosimeters when scanned with a yellow light source

    Science.gov (United States)

    Babic, Steven; Battista, Jerry; Jordan, Kevin

    2008-03-01

    Freshly prepared radiochromic ferrous xylenol-orange (FX) gels optically scanned with a light source exhibit a threshold dose response that is thermally and wavelength dependent. Correction for this threshold dose leads to accurate dose calibration and better reproducibility in multiple fraction radiation exposures. The objective of this study was to determine the cause of the threshold dose effect and to control it through improved dose calibration procedures. The results of a systematic investigation into the chemical cause revealed that impurities within the various FX gel constituents (i.e. xylenol-orange, gelatin, sulfuric acid and ferrous ammonium sulfate) were not directly responsible for the threshold dose. Rather, it was determined that the threshold dose response stems from a spectral sensitivity to different chemical complexes that are formed at different dose levels in FX gels between ferric (Fe(III)) ions and xylenol-orange (XO), i.e. Fe(III)i:XOj. A double Fe(III)2:XO1 complex preferentially absorbs at longer wavelengths (i.e. yellow), while at shorter wavelengths (i.e. green) the sensitivity is biased toward the single Fe(III)1:XO1 complex. As a result, when scanning with yellow light, freshly prepared FX gels require a minimum concentration of Fe(III) ions to shift the equilibrium concentration to favor the predominant production of the double Fe(III)2:XO1 complex at low doses. This can be accomplished via pre-irradiation of freshly prepared gels to a priming dose of ~0.5 Gy or allowing auto-oxidation to generate the startup concentration of Fe(III) ions required to negate the apparent threshold dose response.

  15. New Equation for Prediction of Martensite Start Temperature in High Carbon Ferrous Alloys

    Science.gov (United States)

    Park, Jihye; Shim, Jae-Hyeok; Lee, Seok-Jae

    2018-02-01

    Since previous equations fail to predict M S temperature of high carbon ferrous alloys, we first propose an equation for prediction of M S temperature of ferrous alloys containing > 2 wt pct C. The presence of carbides (Fe3C and Cr-rich M 7C3) is thermodynamically considered to estimate the C concentration in austenite. Especially, equations individually specialized for lean and high Cr alloys very accurately reproduce experimental results. The chemical driving force for martensitic transformation is quantitatively analyzed based on the calculation of T 0 temperature.

  16. Influence of several non ferrous metals in the treatment of residual liquors from sulfuric acid picking processes. Influencia de diversos metales no ferreos en el tratamiento de lejias residuales de decapado con acido sulfurico

    Energy Technology Data Exchange (ETDEWEB)

    Negro, C.; Gonzalez, A.; Latorre, R.; Dufour, J.; Formoso, A.; Lopez-Mateos, F. (Departamento de Ingenieria Quimica. Facultad de Ciencias Quimicas, Universidad Complutense, Madrid (Spain))

    1994-01-01

    In the oxiprecipitation of waste liquors from sulfuric picking processes several kinds of ferrous oxides and oxihydroxides are obtained which can be used like raw materials for the chemical industry. Generally, in this process different mixtures of then are obtained and only in the most drastic conditions, pure products can be obtained. The presence of non-ferrous metals catalyzes and modifies the mechanism of the reaction, yielding pure products. The aim of this work is to determine the influence of Cu(II), Al(III), Zn(II) and Mo(VI) on the oxiprecipitation of residual liquors from sulfuric acid picking processes, selecting the most favorable operation conditions at which it is possible to obtain products for industrial applications. (Author) 20 refs.

  17. The effect of initial pH on the kinetics of ferrous-iron biooxidation at ...

    African Journals Online (AJOL)

    The general understanding in bioleaching of sulphide minerals is to keep pH low. A number of published articles have reported the effect of pH on biooxidation rates of ferrous-iron and/or sulphur by bioleaching microbes, although most of these studies were conducted at optimum or near optimum temperature for microbial ...

  18. CURRENT STATE AND TENDENCIES OF DEVELOPMENT OF FERROUS METALLURGY IN THE EAEU COUNTRIES

    Directory of Open Access Journals (Sweden)

    N. P. Dragun

    2016-01-01

    Full Text Available The analysis of modern status and tendencies of development of ferrous metallurgy in the countries of the EAEU is described in the article. On the basis of the conducted analysis are revealed the identified systemic problems of metallurgy and the conclusions on possible ways of their solution using the potential of integration are given.

  19. Eddy Current Separation of Fine Non-Ferrous Particles from Bulk Streams

    NARCIS (Netherlands)

    Settimo, F.; Bevilacqua, P.; Rem, P.

    2004-01-01

    Recovery of fine non-ferrous metals from waste streams is a notoriously difficult problem in eddy current separation technology. Existing processes either have a low capacity or an incomplete recovery for particle sizes below 5 mm. In a new process, the particles are fed slightly wet to make them

  20. Compatibility of Anti-Wear Additives with Non-Ferrous Engine Bearing Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhou, Yan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-01-01

    Investigate the compatibility of engine lubricant antiwear (AW) additives, specifically conventional zinc dialkyldithiophosphate (ZDDP) and newly developed ionic liquids (ILs), with selected non-ferrous engine bearing alloys, specifically aluminum and bronze alloys that are commonly used in connecting rod end journal bearings and bushings, to gain fundamental understanding to guide future development of engine lubricants

  1. Stabilization of Pb and As in soils by applying combined treatment with phosphates and ferrous iron.

    Science.gov (United States)

    Xenidis, Anthimos; Stouraiti, Christina; Papassiopi, Nymphodora

    2010-05-15

    The chemical immobilization of Pb and As in contaminated soil from Lavrion, Greece, using monocalcium phosphate and ferrous sulfate as stabilizing agents was investigated. Monocalcium phosphate was added to contaminated soil at PO(4) to Pb molar ratios equal to 0, 0.5, 1, 1.5 and 2.5, whereas ferrous sulfate was added at Fe to As molar ratios equal to 0, 2.5, 5, 10 and 20. Phosphates addition to contaminated soil decreased Pb leachability, but resulted in significant mobilization of As. Simultaneous immobilization of Pb and As was obtained only when soil was treated with mixtures of phosphates and ferrous sulfate. Arsenic uptake by plants was also seen to increase when soil was treated only with phosphates, but co-addition of ferrous sulfate was efficient in maintaining As phytoaccumulation at low levels. The addition of at least 1.5M/M phosphates and 10M/M iron sulfate to soil reduced the dissolved levels of Pb and As in the water extracts to values in compliance with the EU drinking water standards. However, both additives contributed in the acidification of soil, decreasing pH from 7.8 to values as low as 5.6 and induced the mobilization of pH sensitive elements, such as Zn and Cd. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  2. Kinetics of Adsorption of Ferrous Ion onto Acid Activated Carbon from Zea Mays Dust

    Directory of Open Access Journals (Sweden)

    P. K. Baskaran

    2011-01-01

    Full Text Available The batch removal of ferrous ion from aqueous solution using low cost adsorbents such as zea mays dust carbon(ZDC under different experimental conditions were investigated in this study. The process parameters studied include agitation time, initial metal ion concentration, carbon dose, pH and temperature. The adsorption followed first order reaction equation and the rate is mainly controlled by intraparticle diffusion. Freundlich and Langmuir isotherm models were applied to the equilibrium data. The adsorption capacity (Qm obtained from the Langmuir isotherm plot were found to 37.17, 38.31, 39.37 and 40.48 mg/g. The temperature variation study showed that the ferrous ions adsorption is endothermic and spontaneous with increased randomness at the solid solution interface. Significant effect on adsorption was observed on varying the pH of the ferrous ion solutions. The Langmuir and Freundlich adsorption isotherms obtained positive ΔH0 value, pH dependent results and desorption of metal ions in mineral acid suggest that the adsorption of ferrous ion on ZDC involves physisorption mechanism.

  3. Bioextraction of Copper from Printed Circuit Boards: Influence of Initial Concentration of Ferrous Iron

    Science.gov (United States)

    Yamane, Luciana Harue; Espinosa, Denise Crocce Romano; Tenório, Jorge Alberto Soares

    Printed circuit boards are found in all electric and electronic equipment and are particularly problematic to recycle because of the heterogeneous mix of organic material, metals, and fiberglass. Additionally, printed circuit boards can be considered a secondary source of copper and bacterial leaching can be applied to copper recovery. This study investigated the influence of initial concentration of ferrous iron on bacterial leaching to recover copper from printed circuit boards using Acidithiobacillus ferrooxidans-LR. Printed circuit boards from computers were comminuted using a hammer mill. The powder obtained was magnetically separated and the non magnetic material used in this study. A shake flask study was carried out on the non magnetic material using a rotary shaker at 30°C, 170 rpm and different initial concentrations of ferrous iron (gL-1): 6.75; 13.57 and 16.97. Abiotic controls were also run in parallel. The monitored parameters were pH, Eh, ferrous iron concentration and copper extraction (spectroscopy of atomic absorption). The results showed that using initial concentration of ferrous iron of 6.75gL-1 were extracted 99% of copper by bacterial leaching.

  4. Wear resistance of alloy вт-22 with non-ferrous alloys at reverse

    Directory of Open Access Journals (Sweden)

    А.М. Хімко

    2010-01-01

    Full Text Available  The article presents the results of tests of non hardened titanium alloy ВТ-22 with aviation non-ferrous alloys in reverse sliding friction. The main objective of the work is the selection of the optimum combination of materials depending on changes in loading conditions. Study of alloy ВТ-22 wear resistance was carried out in pairs with БрОФ-10-1, БрБ2, БрАЖ-9-4, ВТ-22, МЛ5, Д16Т, 7Х21ГАН5Ш and 95Х18Ш. The dependencies of the materials wear at pressures 10, 20 and 30 Mpa we determined. The linear nature of titanium alloy wear curves indicates that the change in the wear mechanism occurs gradually. The histograms of non-ferrous materials wear and the total wear of the friction pair are presented. It is established that the bronze БрАЖ-9-4 is the most preferable material for contact with non hardened titanium alloy ВТ-22, the least wear among the tested materials. The established coefficients of the titanium alloy ВТ-22 friction in pair with aviation structural non-ferrous alloys are presented. The results of research will be relevant for the engineering industry, where non hardened titanium alloy ВТ-22 in pair with non-ferrous alloys is applied.

  5. Mechanism of radiation and thermal decomposition of sulphide non-ferrous metals

    International Nuclear Information System (INIS)

    Mazhrenova, N.P.

    1998-01-01

    This paper deals with the non-ferrous metals sulfides in term of their radiative sensitivity, directed chances of their physical-chemical, and hence technological properties by radiation influence both on sulfide materials and on the processes with their participation. (author)

  6. Probing the Hydrogen Bonding of the Ferrous-NO Heme Center of nNOS by Pulsed Electron Paramagnetic Resonance.

    Science.gov (United States)

    Astashkin, Andrei V; Chen, Li; Elmore, Bradley O; Kunwar, Deepak; Miao, Yubin; Li, Huiying; Poulos, Thomas L; Roman, Linda J; Feng, Changjian

    2015-06-25

    Oxidation of L-arginine (L-Arg) to nitric oxide (NO) by NO synthase (NOS) takes place at the heme active site. It is of current interest to study structures of the heme species that activates O2 and transforms the substrate. The NOS ferrous-NO complex is a close mimic of the obligatory ferric (hydro)peroxo intermediate in NOS catalysis. In this work, pulsed electron-nuclear double resonance (ENDOR) spectroscopy was used to probe the hydrogen bonding of the NO ligand in the ferrous-NO heme center of neuronal NOS (nNOS) without a substrate and with L-Arg or N-hydroxy-L-arginine (NOHA) substrates. Unexpectedly, no H-bonding interaction connecting the NO ligand to the active site water molecule or the Arg substrate was detected, in contrast to the results obtained by X-ray crystallography for the Arg-bound nNOS heme domain [Li et al. J. Biol. Inorg. Chem. 2006, 11, 753-768]. The nearby exchangeable proton in both the no-substrate and Arg-containing nNOS samples is located outside the H-bonding range and, on the basis of the obtained structural constraints, can belong to the active site water (or OH). On the contrary, in the NOHA-bound sample, the nearby exchangeable hydrogen forms an H-bond with the NO ligand (on the basis of its distance from the NO ligand and a nonzero isotropic hfi constant), but it does not belong to the active site water molecule because the water oxygen atom (detected by (17)O ENDOR) is too far. This hydrogen should therefore come from the NOHA substrate, which is in agreement with the X-ray crystallography work [Li et al. Biochemistry 2009, 48, 10246-10254]. The nearby nonexchangeable hydrogen atom assigned as H(ε) of Phe584 was detected in all three samples. This hydrogen atom may have a stabilizing effect on the NO ligand and probably determines its position.

  7. With regard to the fact that the microbial bio-oxidation of ferrous iron ...

    African Journals Online (AJOL)

    User

    2011-02-28

    Feb 28, 2011 ... The application of bioleaching for recovery of other metals has also been explored with some success .... with a rotation speed of 200 rpm and the temperature was maintained at 22°C in an air conditioned ... determined at the end of each run; the liquid in each flask was filtered using a vacuum flask and ...

  8. Further development of the ceric oxidation ferrous reduction dichromate titration method of plutonium determination

    International Nuclear Information System (INIS)

    Macdonald, A.; Savage, D.J.

    1986-02-01

    The chemical reactions involved in the amperometric titration method for plutonium have been further examined, to identify remaining potential sources of bias. As these effects were not expected to be more than 0.1% at the 30 mg plutonium level, a procedure for analysing small (3 mg) aliquots of plutonium has been developed, to help identify any marginal effects. At this reduced level both plutonium and 'blank' determinations indicated that reduction of potassium permanganate by oxalic acid is slower than previously suspected and that a variable small bias can result. Decreasing the concentration of the potassium permanganate eliminated the latter effect. A low bias, proportional to the amount of excess oxalic acid added, was observed. Experiments suggest the bias is due to the reaction of oxalate with an intermediary in the iron II/ dichromate titration. The effect can be adequately reduced by complexing oxalate with cerium III. The reduction of plutonium VI by iron II has been shown to be faster than previously assumed, permitting a decreased waiting time before titration. Minor changes to the original procedure are recommended for analysis of 3 mg aliquots of plutonium. (author)

  9. Ferrous arrowheads and their oil quench hardening: Some early Indian evidence

    Science.gov (United States)

    Dube, R. K.

    2008-05-01

    A wide variety of ferrous arrowheads were in use in ancient India. Several typical chemical analyses of arrowheads found from archaeological excavation carried out at Kaushambi are reported in this paper. The average carbon content of these arrowheads varied from as low as 0.1 wt.% to approximately 0.9 wt.%. Literary evidence for oil quench hardening of ferrous arrowheads, as reported in famous Sanskrit epics—the Rāmāyana and the Mahābhārata—have been discussed in this paper. This type of quench hardening was intentionally adopted as it helped in preventing distortion and formation of quench cracks in arrowheads. The oil quench-hardened arrowheads were rubbed on stones to sharpen them, which also brought about tempering of martensite due to frictional heat.

  10. Conflitos ambientais: uma análise da assimetria de poder entre os atores sociais envolvidos no caso do Mineroduto da Ferrous / Environmental conflict: an analysis of power asymmetry between social actors involved in the case of Ferrous Pipeline

    Directory of Open Access Journals (Sweden)

    Dayane Rouse Neves Sousa

    2015-12-01

    Full Text Available This work intends to present the environmental conflict initiated due to the installation of pipeline Ferrous Ressources S / A, in the micro region of Viçosa-MG, building an analysis of the positioning of the main social actors involved, as well as their respective relations of power. Thepipeline of Ferrous will connect the complex Beam Mine in Congonhas-MG, the port of Ferrous Ressources in Presidente Kennedy-ES in order to export iron ore. To do so, were used as methodological procedures: bibliographical research; document analysis; semi-structured interviews with different actors; and follow-up meetings of the Popular Campaign Against the Water and Pipeline Ferrous, public hearings and demonstrations taken place in the Viçosa. Furthermore, there was monitoring of the pipeline discussion in local newspapers and on blogs. Thus, this study demonstrated that the Ferrous company, which owns high economic and symbolic power, assumes the role of dominating the conflict. On the other hand, those affected and social movements against the construction of the project, are sometimes in the role of dominated, leaving them to articulate strategies of resistance to delay / stop the construction of the pipeline. The state, in turn, assumes different roles in this context, demonstrating thereby weakness in mediation and conflict management established by pipeline Ferrous mainly in the micro region of Viçosa-MG.

  11. Separation of non-ferrous metals from ASR by corona electrostatic separation

    Science.gov (United States)

    Kim, Yang-soo; Choi, Jin-Young; Jeon, Ho-Seok; Han, Oh-Hyung; Park, Chul-Hyun

    2016-04-01

    Automotive shredder residue (ASR), the residual fraction of approximate 25% obtained after dismantling and shredding from waste car, consists of polymers (plastics and rubber), metals (ferrous and non-ferrous), wood, glass and fluff (textile and fiber). ASR cannot be effectively separated due to its heterogeneous materials and coated or laminated complexes and then largely deposited in land-fill sites as waste. Thus reducing a pollutant release before disposal, techniques that can improve the liberation of coated (or laminated) complexes and the recovery of valuable metals from the shredder residue are needed. ASR may be separated by a series of physical processing operations such as comminution, air, magnetic and electrostatic separations. The work deals with the characterization of the shredder residue coming from an industrial plant in korea and focuses on estimating the optimal conditions of corona electrostatic separation for improving the separation efficiency of valuable non-ferrous metals such as aluminum, copper and etc. From the results of test, the maximum separation achievable for non-ferrous metals using a corona electrostatic separation has been shown to be recovery of 92.5% at a grade of 75.8%. The recommended values of the process variables, particle size, electrode potential, drum speed, splitter position and relative humidity are -6mm, 50 kV, 35rpm, 20° and less 40%, respectively. Acknowledgments This study was supported by the R&D Center for Valuable Recycling (Global-Top R&BD Program) of the Ministry of Environment. (Project No. GT-11-C-01-170-0)

  12. Determination of reliability of express forecasting evaluation of radiometric enriching ability of non-ferrous ores

    International Nuclear Information System (INIS)

    Kirpishchikov, S.P.

    1991-01-01

    Use of the data of nuclear physical methods of sampling and logging enables to improve reliability of evaluation of radiometric enriching ability of ores, as well as to evaluate quantitatively this reliability. This problem may be solved by using some concepts of geostatistics. The presented results enable to conclude, that the data of nuclear-physical methods of sampling and logging can provide high reliability of evaluation of radiometric enriching ability of non-ferrous ores and their geometrization by technological types

  13. Studying phase structure of burned ferrous manganese ores by method of nuclear gamma-resonance spectroscopy

    OpenAIRE

    Shayakhmetov, B.; Issagulov, A.; Baisanov, A.; Karakeyeva, G.; Issagulovа, D.

    2014-01-01

    In the given article there are presented the results of studying the phase structure of burned ferrous manganese ores of Zhomart and Zapadny Kamys deposits of by the method of Mossbauer spectroscopy. There is established a variety of iron location forms in the studied materials and their quantitative content that allows to define the degree of completing regenerative processes at magnetizing roasting, and also the processes of formation of solid solutions (Fe1-XMX3O4 and stabilization of Fe1-...

  14. Stress corrosion cracking of several high strength ferrous and nickel alloys

    Science.gov (United States)

    Nelson, E. E.

    1971-01-01

    The stress corrosion cracking resistance of several high strength ferrous and nickel base alloys has been determined in a sodium chloride solution. Results indicate that under these test conditions Multiphase MP35N, Unitemp L605, Inconel 718, Carpenter 20Cb and 20Cb-3 are highly resistant to stress corrosion cracking. AISI 410 and 431 stainless steels, 18 Ni maraging steel (250 grade) and AISI 4130 steel are susceptible to stress corrosion cracking under some conditions.

  15. Synthesis and characterization of a ferrous compound material obtained by combustion of ferroboron and ferrotitanium mixtures

    International Nuclear Information System (INIS)

    Bejar, M.A; Fuenzalida, J.L

    2008-01-01

    A ferrous compound material was synthesized in this work, by the air auto-combustion of mixtures of powdered ferroboron and ferrotitanium, compacted under pressures of 79 and 93 MPa and preheated to a temperature of about 1000 o C. The synthesized compounds were characterized by XRD analysis, and macro and micro-hardness tests. The formation of titanium diboride was found in all the synthesized test pieces (au)

  16. Synthesis and characterization of ferrous phosphate (vivianite) and its behavior in aqueous media

    International Nuclear Information System (INIS)

    Diaz F, J.C.

    2003-01-01

    The synthesis and characterization of materials that can be useful in Environmental Chemistry is very important because their characteristics are exposed and its behavior in chemical phenomena as the sorption in aqueous media is understand to use it in the human being benefit. With the object of using, in a future, the octa hydrated ferrous phosphate (vivianite) as a potential candidate for matrix confinement in contention walls for the storage of radioactive waste of long half life, it was synthesized and it characterized physico chemically and their properties of surface of this compound were evaluated. Presently work was carried out the synthesis and structural characterization of the iron phosphate II by infrared spectroscopy with having Fourier transform, high vacuum scanning electron microscopy, X-ray diffraction, thermal gravimetric analysis, the BET multipoint surface area and Moessbauer spectroscopy; as well as, the determination between aqueous media of the isoelectric point and the density of sites of surface of the compound. The octa hydrated ferrous phosphate was obtained pure. The results indicate that the product corresponds to the prospective mineral, the vivianite. The thermal gravimetric analysis demonstrated that the ferrous phosphate is a stable salt after the lost of water. The isoelectric point is since an important parameter because allows to know the behavior of the surface of the material in aqueous systems, in this case the isoelectric point, of the octa hydrated ferrous phosphate, in distilled water is of pH 4.20 and in solution of potassium nitrate 0.5 M is of pH = 3.75. This indicates that the material has an amphoteric surface depending on the pH. On the other hand, the density of active sites of surface obtained by titrations acid-base is of 20 sites by nm 2 . (Author)

  17. COMPARATIVE STUDY OF EFFICACY OF FERROUS SULPHATE AND CARBONYL IRON IN ANEMIA OF ANTENATAL WOMEN

    Directory of Open Access Journals (Sweden)

    Radhika

    2015-03-01

    Full Text Available Iron deficiency anemia is the most common and important public health problem all over the world in the risk group of antenatal women. Research is going on to improve the iron status of the pregnant women with different forms of iron available. In this regard, Carbonyl Iron is showing promising results in improving the red cell mass with better compliance. 120 antenatal women were recruited in this study. The study comprised of 6weeks for each patient. They were given Carbonyl Iron 100 mg/day and FeS04 100gm/day . Before and after treatment all the baseline and specific investigations were one. Results were tabulated, comparison and significance were tested by unpaired student ’s’ test and their 'p' value was calculated. Results were shown graphically also. Carbonyl Iron showed improvement in hemoglobin, PCV and better than ferrous Sulphate (P <0.001. Incidence of side effects were less with Carbonyl Iron than Ferrous Sulphate, better compliance was seen with Carbonyl Iron. In conclusion, the present study s howed that Carbonyl Iron had better efficacy and safety in the management of Iron deficiency anemia in antenatal women than ferrous Sulphate

  18. Sorption of ferrous iron by EPS from the acidophilic bacterium Acidiphilium Sp.: A mechanism proposal

    International Nuclear Information System (INIS)

    Tapia, J.M.; MuNoz, J.; Gonzlez, F.; Blazquez, M.L.; Ballester, A.

    2016-01-01

    The aim of this work was to assess the uptake of Fe(II) by extracellular polymeric substances (EPS) from the acidophilic bacterium Acidiphillium 3.2Sup(5). These EPS were extracted using EDTA. EPS of A. 3.2Sup(5) loaded in sorption tests with Fe(II), were characterized using the following experimental techniques: scanning electron microscopy (SEM) with energy dispersive X-ray microanalysis (EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The experimental results indicate that EPS adsorb ferrous iron according to Freundlich model with a metal sorption uptake of K = 1.14 mg1−1/n L1/n g−1 and a sorption intensity of 1/n = 1.26. In addition, ferrous iron sorption by EPS took place by preferential interaction with the carboxyl group which promotes the formation of ferrous iron oxalates (FeC2O4). Since the interaction reaction was reversible (Log K = 0.77 ± 0.33), that means that the cation sorption can be reversed at convenience. (Author)

  19. Sorption of ferrous iron by EPS from the acidophilic bacterium Acidiphilium Sp.: A mechanism proposal

    Energy Technology Data Exchange (ETDEWEB)

    Tapia, J.M.; MuNoz, J.; Gonzlez, F.; Blazquez, M.L.; Ballester, A.

    2016-07-01

    The aim of this work was to assess the uptake of Fe(II) by extracellular polymeric substances (EPS) from the acidophilic bacterium Acidiphillium 3.2Sup(5). These EPS were extracted using EDTA. EPS of A. 3.2Sup(5) loaded in sorption tests with Fe(II), were characterized using the following experimental techniques: scanning electron microscopy (SEM) with energy dispersive X-ray microanalysis (EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The experimental results indicate that EPS adsorb ferrous iron according to Freundlich model with a metal sorption uptake of K = 1.14 mg1−1/n L1/n g−1 and a sorption intensity of 1/n = 1.26. In addition, ferrous iron sorption by EPS took place by preferential interaction with the carboxyl group which promotes the formation of ferrous iron oxalates (FeC2O4). Since the interaction reaction was reversible (Log K = 0.77 ± 0.33), that means that the cation sorption can be reversed at convenience. (Author)

  20. The effect of adding ferrous sulfate to methylphenidate on attention-deficit/hyperactivity disorder in children

    Directory of Open Access Journals (Sweden)

    Gholamreza Panahandeh

    2017-01-01

    Full Text Available Attention deficit/hyperactivity disorder (ADHD is one of the most common psychiatric disorders in children with several complications. This study was conducted to investigate the effect of adding ferrous sulfate to methylphenidate in decreasing ADHD symptoms. This study was a double-blind, randomized clinical trial. In this study, 42 nonanemic children with ADHD and serum ferritin below 30 mg/ml were enrolled according to convenience sampling and randomly assigned to two groups of 21 each, cases and controls. The two groups were matched for age and sex. The case group was administered with ferrous sulfate 5 mg/kg in addition to methylphenidate up to 1 mg/kg and the control group with methylphenidate alone. The scores on child symptoms inventory-4 (CSI-4 were recorded at baseline and after 2 months of treatment. Data were analyzed by t-test, Pearson's correlation coefficient, and repeated measures ANOVA in SPSS 16. The scores on CSI-4 decreased significantly at month 2 in both groups (P < 0.001. The scores on attention deficit and hyperactivity subscales of the CSI-4 were significantly lower in the case group than the control group (P < 0.05. The total score on CSI-4 decreased more markedly in the case group (P < 0.04. Use of ferrous sulfate plus methylphenidate can be effective in reducing ADHD symptoms in nonanemic children with low serum ferritin.

  1. Oral iron therapy in human subjects, comparative absorption between ferrous salts and iron polymaltose

    International Nuclear Information System (INIS)

    Jacobs, P.; Johnson, G.; Wood, L.

    1984-01-01

    Iron absorption was directly compared between equivalent doses of ferrous salts and a polymaltose complex using a twin-isotope technique in which each individual acts as his own control. In the first study, bioavailability of iron from ferrous sulfate and the complex was defined at physiologic doses of 5 mg (Group 1: n = 14) and therapeutic doses of 50 mg (Group 2: n = 13). In Group 1, mean absorption from salt was 47.77% (SD 14.58%) and from polymaltose, 46.56% SD 17.07%). In Group 2, mean absorption from salt was 32.92% (SD 13.42%) and from polymaltose, 27.07% (SD 6.50%). In a second study, 100 mg of iron in a chewable formulation was used to compare absorption between equal doses of ferrous fumarate and the polymaltose complex. Mean absorption from salt was 10.25% (SD 6.89%) and from polymaltose 10.68% (SD 4.68%). At all three dosage levels, iron is equally available from salt or polymaltose for hemoglobin synthesis (p greater than 0.20), and absorption negatively correlated with plasma ferritin (p less than 0.01). These two materials may be used interchangeably in the treatment of patients with absolute iron deficiency

  2. Avaliação por métodos in vitro e in vivo da biodisponibilidade de sulfato ferroso microencapsulado In vitro and in vivo evaluation of iron bioavailability from microencapsulated ferrous sulfate

    Directory of Open Access Journals (Sweden)

    Maria Lucia Cocato

    2007-06-01

    Full Text Available OBJETIVO: Avaliar, por métodos in vitro e in vivo, a biodisponibilidade de uma nova forma de sulfato ferroso microencapsulado (genericamente denominado Ferlim, desenvolvido para a fortificação de alimentos, comparando-a com a de ferro eletrolítico (Fe0. MÉTODOS: A avaliação da dialisabilidade in vitro utilizou como matriz leite em pó reconstituído. A avaliação in vivo, utilizando o método de recuperação de hemoglobina em leitões anêmicos, teve duração de 13 dias e os animais (n=23 foram agrupados de acordo com o produto do peso (kg x hemoglobina (g/dL. Como controle foi utilizado FeSO4.7H2O. RESULTADOS: As porcentagens médias de ferro dialisado foram 2,2 (desvio-padrão=0,1%, 3,4 (desvio-padrão=0,1% e 3,6 (desvio-padrão=0,0% para FeSO4.7H2O, Ferlim e Fe0, respectivamente (p0,05. As porcentagens de absorção do valor biológico relativo do FeSO4.7H2O foram de 94,2 (desvio-padrão=23,8% para o grupo Ferlim e de 79,7 (desvio-padrão=26,6% para o grupo Fe0, sem diferenças significantes (p>0,05. Em valores numéricos (p>0,05, o grupo Fe0 apresentou menor média de absorção (% valor biológico relativo de concentração de ferro total, de ferro heme e não-heme no fígado. CONCLUSÃO: A microencapsulação do sulfato ferroso com alginato mantém sua biodisponibilidade, caracterizando-se como boa alternativa para a fortificação de misturas sólidas.OBJECTIVE: To evaluate, by in vitro and in vivo methods, the bioavailability of a new microencapsulated ferrous sulfate (Ferlim developed for food fortification, and compare it with electrolytic iron (Fe0. METHODS: In vitro dialyzability assessment used reconstituted milk powder as matrix. In vivo assessment using the hemoglobin regeneration method in anemic piglets lasted for 13 days and the animals (n=23 were grouped according to the product of weight (kg x hemoglobin (g/dL. FeSO4.7H2O was used as control. RESULTS: The percentages of dialyzed iron were 2.2 (standard deviation=0

  3. OXIDATIVE DEGRADATION OF 2-CHLOROPHENOL BY PERSULFATE

    Directory of Open Access Journals (Sweden)

    Krzysztof Kuśmierek

    2015-06-01

    Full Text Available The degradation of 2-chlorophenol (2-CP by persulfate was investigated. The kinetics of persulfate oxidation of 2-chlorophenol in aqueous solutions at various pH, oxidant concentration, temperature, Fe2+ and Cu2+ ions content was studied. Maximum of 2-CP degradation occurred at pH 8. The oxidation rate of 2-CP increased with increasing the persulfate molar excess. The degradation process was significantly influenced by temperature – the higher temperature results in a faster degradation of 2-CP. The activation of persulfate by ferrous and copper ions was also studied. Results showed that persulfate is activated more effectively by iron(II than copper(II ions. A comparison of different persulfate activation methods revealed that heat-activation was the most effective. Under optimal conditions, in the presence of ferrous ions at 50 °C, complete degradation of 2-chlorophenol was achieved after about 30 minutes.

  4. Elucidating the role of ferrous ion cocatalyst in enhancing dilute acid pretreatment of lignocellulosic biomass

    Directory of Open Access Journals (Sweden)

    Wei Hui

    2011-11-01

    Full Text Available Abstract Background Recently developed iron cocatalyst enhancement of dilute acid pretreatment of biomass is a promising approach for enhancing sugar release from recalcitrant lignocellulosic biomass. However, very little is known about the underlying mechanisms of this enhancement. In the current study, our aim was to identify several essential factors that contribute to ferrous ion-enhanced efficiency during dilute acid pretreatment of biomass and to initiate the investigation of the mechanisms that result in this enhancement. Results During dilute acid and ferrous ion cocatalyst pretreatments, we observed concomitant increases in solubilized sugars in the hydrolysate and reducing sugars in the (insoluble biomass residues. We also observed enhancements in sugar release during subsequent enzymatic saccharification of iron cocatalyst-pretreated biomass. Fourier transform Raman spectroscopy showed that major peaks representing the C-O-C and C-H bonds in cellulose are significantly attenuated by iron cocatalyst pretreatment. Imaging using Prussian blue staining indicated that Fe2+ ions associate with both cellulose/xylan and lignin in untreated as well as dilute acid/Fe2+ ion-pretreated corn stover samples. Analyses by scanning electron microscopy and transmission electron microscopy revealed structural details of biomass after dilute acid/Fe2+ ion pretreatment, in which delamination and fibrillation of the cell wall were observed. Conclusions By using this multimodal approach, we have revealed that (1 acid-ferrous ion-assisted pretreatment increases solubilization and enzymatic digestion of both cellulose and xylan to monomers and (2 this pretreatment likely targets multiple chemistries in plant cell wall polymer networks, including those represented by the C-O-C and C-H bonds in cellulose.

  5. Oxidation-reduction potentials of different chlorophylls in methanol

    NARCIS (Netherlands)

    Goedheer, J.C.; Horreus de Haas, G.H.; Schuller, P.

    1958-01-01

    It was found that the reversible decolorisation of some chlorophylls upon the subsequent addition of ferric and ferrous salts, as originally measured by Rabinowtich and Weiss for chlorophyll a, proceeded at a reproducible oxidation-reduction potential. A marked difference was found to occur

  6. Studying phase structure of burned ferrous manganese ores by method of nuclear gamma-resonance spectroscopy

    Directory of Open Access Journals (Sweden)

    B. Shayakhmetov

    2014-04-01

    Full Text Available In the given article there are presented the results of studying the phase structure of burned ferrous manganese ores of Zhomart and Zapadny Kamys deposits of by the method of Mossbauer spectroscopy. There is established a variety of iron location forms in the studied materials and their quantitative content that allows to define the degree of completing regenerative processes at magnetizing roasting, and also the processes of formation of solid solutions (Fe1-XMX3O4 and stabilization of Fe1-XO from eutectoid disintegration at cooling.

  7. Clean ferrous casting technology research. Final technical report, September 29, 1993--December 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Bates, C.E.; Griffin, J.; Giese, S.R.; Lane, A.M. [and others

    1996-01-31

    This is the final report covering work performed on research into methods of attaining clean ferrous castings. In this program methods were developed to minimize the formation of inclusions in steel castings by using a variety of techniques which decreased the tendency for inclusions to form during melting, casting and solidification. In a second project, a reaction chamber was built to remove inclusions from molten steel using electromagnetic force. Finally, a thorough investigation of the causes of sand penetration defects in iron castings was completed, and a program developed which predicts the probability of penetration formation and indicates methods for avoiding it.

  8. Evaporation Rate of Distilled Water Drop on the Surface of Non-Ferrous Metals

    Directory of Open Access Journals (Sweden)

    Ponomarev Konstantin

    2015-01-01

    Full Text Available We studied experimentally the evaporation process of distilled water drops on the surfaces of non-ferrous metals. Investigations were conducted on the experimental setup using a shadow optical system. The main elements of this system are the source of plane-parallel light and photographic camera. According to the contact diameter change during the evaporation, three stages have been determined (spreading, pinning, depinning. It has been found, that the dependence of evaporation rate on drop volume at low temperatures appear to be well fit by a power function.

  9. Determination of TBP, HDEHP and TOPO complexed with ferrous thiocyanate by reversed phase liquid chromatography

    International Nuclear Information System (INIS)

    Akliouant, Z.; Meddour, L.; Azzouz, A.

    1992-02-01

    The present work deals with the analysis of some organophosphorus extracting agents, e.g. TBP, HDEHP and TOPO by reversed phase liquid chromatography via previous complexation with ferrous thiocyanate. The absorbance wavelengths of the resulting complexes, i.e. TBP:FeSCNK, HDEHP:FeSCNK and TOPO:FeSCNK are respectively 427, 446 and 487nm. Thus, an improvement of such a technique consists in the organophosphorus compounds detection by colorimetry. Subsequently all products and intermediates present in synthesis media can be easily analysed in the same wavelengths range without previous separation or purification

  10. Study on fluorescence properties of carbogenic nanoparticles and their application for the determination of ferrous succinate

    Energy Technology Data Exchange (ETDEWEB)

    Sun Wen [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009 (China); Du Yingxiang, E-mail: du_yingxiang@126.co [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009 (China) and Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, Nanjing 210009 (China) and Key Laboratory of Modern Chinese Medicines, Ministry of Education, China Pharmaceutical University, Nanjing 210009 (China); Wang Yunqing [Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China)

    2010-08-15

    A new type of fluorescent nanomaterial named carbogenic nanoparticles (NPs) has drawn considerable attention recently. In this study, we adopted a direct and simple synthetic method to produce the carbogenic NPs and investigated the fluorescence properties of the as-prepared carbogenic NPs in detail. It was found that the fluorescence of carbogenic NPs was stable with the variance of environmental conditions such as pH, temperature and UV irradiation. More interestingly, we found carbogenic NPs exhibited high selectivity and sensitivity towards ferric ions. Under optimum conditions, a good linear relationship could be obtained between the fluorescence intensity and concentration of ferric ions in the range of 5.0x10{sup -5}-5.0x10{sup -4} mol L{sup -1}, and the limit of detection is 11.2 {mu}mol L{sup -1}. Based on the fluorescence quenching of carbogenic NPs, a rapid and specific quantitative method was proposed for the determination of ferrous succinate. The content of ferrous succinate in commercial tablets determined by the present method was agreed with the spectrophotometric method results and the reproducibility and the recovery of the proposed method were satisfactory.

  11. Prospects for Ukrainian ferrous metals in the post-soviet period

    Science.gov (United States)

    Levine, R.M.; Bond, A.R.

    1998-01-01

    Two specialists on the mineral industries of the countries of the former USSR survey current problems confronting producers of ferrous metals in Ukraine and future prospects for domestic production and exports. A series of observations documenting the importance of ferrous metals production to Ukraine's economy is followed by sections describing investment plans and needs in the sector, and the role played by Ukraine within the iron and steel industry of the Soviet Union. The focus then turns to assessment of the current regional and global competitive position of Ukrainian producers for each of the major commodities of the sector-iron ore, manganese ore, ferroalloys, steel, and the products of the machine manufacturing and metal working industries. In conclusion, the paper discusses a potential regional industrial integration strategy analogous to that employed in the United States' Great Lakes/Midwest region, which possesses similar types of iron ore deposits and similar transport cost advantages and metallurgical and manufacturing industries. Journal of Economic Literature, Classification Numbers: F14, L61, L72. 1 table, 26 references.

  12. Molecular characterization of whey protein hydrolysate fractions with ferrous chelating and enhanced iron solubility capabilities.

    Science.gov (United States)

    O'Loughlin, Ian B; Kelly, Phil M; Murray, Brian A; FitzGerald, Richard J; Brodkorb, Andre

    2015-03-18

    The ferrous (Fe2+) chelating capabilities of WPI hydrolysate fractions produced via cascade membrane filtration were investigated, specifically 1 kDa permeate (P) and 30 kDa retentate (R) fractions. The 1 kDa-P possessed a Fe2+ chelating capability at 1 g L(-1) equivalent to 84.4 μM EDTA (for 30 kDa-R the value was 8.7 μM EDTA). Fourier transformed infrared (FTIR) spectroscopy was utilized to investigate the structural characteristics of hydrolysates and molecular interactions with Fe2+. Solid-phase extraction was employed to enrich for chelating activity; the most potent chelating fraction was enriched in histidine and lysine. The solubility of ferrous sulfate solutions (10 mM) over a range of pH values was significantly (Piron solubility was improved by 72% in the presence of the 1 kDa-P fraction following simulated gastrointestinal digestion (SGID) compared to control FeSO4·7H2O solutions.

  13. Possibilities for saving energy in ferrous metallurgy: Integration of technological processes

    Directory of Open Access Journals (Sweden)

    Mihailov Emil

    2016-01-01

    Full Text Available One of the main factors having a significant effect on fuel and energy saving in the production of rolled ferrous metals is matching the operation of the continuous casting machines (CCM with that of the reheating furnaces so called “continuous technologies” in the form of “direct rolling” or “hot charging”. In order to investigate the heat exchange processes, the opportunities for enhancing the energy efficiency and determining the optimal parameters of the flat product production process in ferrous metallurgy, some mathematical models of metal solidification and cooling in a continuous steel casting machine were determined as well as a mathematical model of metal heating in the reheating furnaces. For efficient implementation of such technologies one common algorithm was built on the basis of the individual mathematical models, representing the continuous casting - rolling mill complex control technology, dynamically matching the operation of the individual units to the actual production conditions in on-line mode. The developed algorithm can be used as part of a system for analyzing the thermal condition of the blocks at any single moment for the purpose of optimization of the units’ operation within the whole technological process. As a conclusion, considering the original developed algorithm, a 21-51% energy saving was noticed.

  14. Study of dosimetric systems-ferrous sulfate-ferric sulfate, glass slides and dyed aqueous solutions

    International Nuclear Information System (INIS)

    Fernandes, L.

    1979-01-01

    The effect of some variables which can effect the preparation of the ferrous sulfate used as dosimetric solution has been studied. Among these variables the purity of the water used for the preparation of the solution and the presence (or absence) of oxygen in the dosimetric solution were considered. The dose rate distribution according to the transverse and longitudinal sections of the Co 60 irradiator was studied experimentally, using the dosimetric solution, and theoretically, using a computer program (KIFE). The results obtained with the ferrous sulface dosimetric solution were used as reference for the study of the application of EM and MSG glass slide as a dosimetric system. For this purpose the effects of the weakening of the coloration induced in the glass by gamma rays (Co 60 ) and the relationship between the absorbed dose of radiation and the ratio between the variation in absorbation value and the thickness of the glass irradiated, were studied. A study was also made of the use of the dye indicators bromothymol-blue, methyl-orange, Congo-red, neutral-red and p-nitrophenol, in aqueous solution, for radiation dose measurements. The bleaching of each indicator solution, under gamma-radiation (Co 60 ) was studied in oxygen and nitrogen atmospheres.(Author) [pt

  15. Recovery of ferrous and nonferrous metal from ASR by physical separation

    Science.gov (United States)

    Kim, Min-gyu; Han, Oh-hyung; Park, Chul-hyun

    2017-04-01

    A recycle ratio of waste automobiles in Korea is low, compared to that of the advanced countries. Especially in its recycle, separation of automotive shredder residue (ASR), the residual fraction of approximate 25% obtained after dismantling and shredding from waste car, is needed. However ASR is cannot be effectively separated due to its heterogeneous materials and coated or laminated complexes and then is largely deposited in land-fill sites as waste. In this study ASR was separated by a series of physical processing operations such as comminution, air classification and magnetic separation and electrostatic separations. In particular it focuses on estimating the optimal conditions of magnetic and electrostatic separations for improving the separation efficiency of valuable ferrous and non-ferrous metals such as iron (Fe), aluminum, copper and etc. In magnetic separation, 91.5% Fe grade and 91% recovery could be obtained at conditions of particle size under 10mm and magnetic intensity of 400 gauss. In corona electrostatic separation for recovering nonferrous metals, a grade of 79.2% and recovery of 90.7% could be successfully achieved under conditions of -6mm particle size, 50kV electrode potential, 35rpm drum speed and 20 degree splitter position, respectively. Acknowledgments This study was supported by the R&D Center for Valuable Recycling (Global-Top R&BD Program) of the Ministry of Environment. (Project No. 2016002250001)

  16. Effect of ferrous ion on ε-poly-L-lysine biosynthesis by Streptomyces diastatochromogenes CGMCC3145.

    Science.gov (United States)

    Wang, Guoliang; Jia, Shiru; Wang, Tian; Chen, Liye; Song, Qingchao; Li, Weina

    2011-03-01

    ε-Poly-L-lysine (ε-PL) is known as an amino acid homopolymer occurring in nature. It is mainly produced by bacteria belonging to the family of Streptomycetaceae. In this study, the effect of ferrous ion on the metabolic pathway such as key enzyme activities and substrate consumptions relating to ε-PL production were investigated. When 0.1 mM Fe(2+) was supplemented into the culture medium of Streptomyces diastatochromogenes CGMCC3145 for 72 h of cultivation, the yield of ε-PL and biomass were enhanced by 29.2 and 41.9%, respectively, compared with those of the control. Synchronously, consumptions of glucose, ammoniac nitrogen, and phosphorus were increased by 50, 67.6, and 35.7%, respectively. The enzyme activity measurements showed that the specific activities of proteinase, phosphatase, glutamate dehydrogenase, and aspartate aminotransferase activities were improved for 2.32, 3.68, 1.72, and 1.50 folds, respectively, however, aspartokinase and ε-PL synthetase were hardly affected by ferrous ion. These results manifested that Fe(2+) can improve the yield of ε-PL by promoting aspartate production, and the aspartate was further catalyzed to produce much more L-lysine, precursor for ε-PL biosynthesis.

  17. Ferrous Ion and Medium Composition Effects on Acidogenic Phase in Biobutanol Production from Molasses

    Science.gov (United States)

    Restiawaty, E.; Grinanda, D.

    2017-07-01

    Clostridium acetobutylicum B530 has ability to convert sugar into biobutanol through two phases, i.e. acidogenic and solventogenic. This fermentation process is often hampered by high raw material cost and low product yield. In order to suppress the production cost, the molasses, a byproduct of sugar cane process production, was used as carbon source in this research. Molasses has nitrogen content in a small amount, thus could be negating the beef extract component, which is expected not to affect the growth of C. acetobutylicum B530 and also can reduce the production cost. In addition, a certain amount of Fe2+ (ferrous ion), a precursor in the formation of the enzyme ferredoxin, was added to the fermentation medium to contribute in the synthesis of acetyl-CoA, so that the formation of acidogenic products such as butyric acid and acetic acid is affected. This study aimed to investigate the effect of ferrous ion and the medium composition in acidogenic phase. The addition of 20 ppm FeSO4.7H2O in the fermentation medium without beef extract can increase the concentration of butyric acid by 20% at a temperature of 35°C, while acetic acid concentration decreased by 6%. According to those results, it is expected that the product selectivity of butanol will increase in solventogenic phase. In addition, the removal of beef extract in the fermentation medium does not affect the kinetics of growth of C. acetobutylicum B530.

  18. The photochemical origins of life and photoreaction of ferrous ion in the archaean oceans

    Science.gov (United States)

    Mauzerall, David C.

    1990-01-01

    A general argument is made for the photochemical origins of life. A constant flux of free energy is required to maintain the organized state of matter called life. Solar photons are the unique source of the large amounts of energy probably required to initiate this organization and certainly required for the evolution of life to occur. The completion of this argument will require the experimental determination of suitable photochemical reactions. It is shown that biogenetic porphyrins readily photooxidize substrates and emit hydrogen in the presence of a catalyst. These results are consistent with the Granick hypothesis, which relates a biosynthetic pathway to its evolutionary origin. It has been shown that photoexcitation of ferrous ion at neutral pH with near ultraviolet light produces hydrogen with high quantum yield. This same simple system may reduce carbon dioxide to formaldehyde and further products. These reactions offer a solution to the dilemma confronting the Oparin-Urey-Miller model of the chemical origin of life. If carbon dioxide is the main form of carbon on the primitive earth, the ferrous photoreaction may provide the reduced carbon necessary for the formation of amino acids and other biogenic molecules. These results suggest that this progenitor of modern photosynthesis may have contributed to the chemical origins of life.

  19. Iron deficiency up-regulates iron absorption from ferrous sulphate but not ferric pyrophosphate and consequently food fortification with ferrous sulphate has relatively greater efficacy in iron-deficient individuals

    NARCIS (Netherlands)

    Zimmermann, M.B.; Biebinger, R.; Egli, I.; Zeder, C.; Hurrell, R.F.

    2011-01-01

    Fe absorption from water-soluble forms of Fe is inversely proportional to Fe status in humans. Whether this is true for poorly soluble Fe compounds is uncertain. Our objectives were therefore (1) to compare the up-regulation of Fe absorption at low Fe status from ferrous sulphate (FS) and ferric

  20. Characterization of arsenic resistant and arsenopyrite oxidizing Acidithiobacillus ferrooxidans from Hutti gold leachate and effluents.

    Science.gov (United States)

    Dave, Shailesh R; Gupta, Kajal H; Tipre, Devayani R

    2008-11-01

    Four arsenic resistant ferrous oxidizers were isolated from Hutti Gold Mine Ltd. (HGML) samples. Characterization of these isolates was done using conventional microbiological, biochemical and molecular methods. The ferrous oxidation rates with these isolates were 16, 48, 34 and 34 mg L(-1)h(-1) and 15, 47, 34 and 32 mg L(-1)h(-1) in absence and presence of 20 mM of arsenite (As3+) respectively. Except isolate HGM 8, other three isolates showed 2.9-6.3% inhibition due to the presence of 20 mM arsenite. Isolate HGM 8 was able to grow in presence of 14.7 g L(-1) of arsenite, with 25.77 mg L(-1)h(-1) ferrous oxidation rate. All the four isolates were able to oxidize iron and arsenopyrite from 20 g L(-1) and 40 g L(-1) refractory gold ore and 20 g L(-1) refractory gold concentrate. Once the growth was established pH adjustment was not needed inspite of ferrous oxidation, which could be due to concurrent oxidation of pyrite. Isolate HGM 8 showed the final cell count of as high as 1.12 x 10(8) cells mL(-1) in 40 g L(-1) refractory gold ore. The isolates were grouped into one haplotypes by amplified ribosomal DNA restriction analysis (ARDRA). The phylogenetic position of HGM 8 was determined by 16S rDNA sequencing. It was identified as Acidithiobacillus ferrooxidans and strain name was given as SRHGM 1.

  1. Oxidants for uranium leaching

    International Nuclear Information System (INIS)

    Ho, E.; Ring, B.

    2007-01-01

    Most uranium ores are leached with sulfuric acid under oxidising conditions. This paper reviews the oxidants that have been traditionally used in uranium leaching and discusses their merits in the context of overall flow sheet considerations. Options for alternative oxidants are also discussed. In acid leaching, ferric ion in solution oxidises insoluble uranium(IV) to soluble uranium (VI). Though ferric ion may be added directly, usually an oxidant is added to the circuit to convert ferrous ion to ferric ion in the liquor so that leaching can continue. The most common oxidants are pyrolusite and sodium chlorate. Pyrolusite is relatively cheap but introduces manganese ions into the liquor and consumes twice as much acid as sodium chlorate. Sodium chlorate is a slow reacting oxidant at low temperatures and acidities, and introduces chloride into the leach liquor. Caro's acid, is a non-polluting reagent that was used successfully at the Nabarlek uranium mine, and provided very good control of oxidising conditions. Other oxidants that are now being considered to overcome the disadvantages of pyrolusite and sodium chlorate are oxygen, hydrogen peroxide and SO 2 /O 2 . Some performance data for these oxidants are presented

  2. Summary reports of the R and D programme: recycling of non-ferrous metals (1986-1989)

    International Nuclear Information System (INIS)

    Donato, M.

    1992-01-01

    This document contains the summary reports of cost sharing research and development contracts funded under the recycling of non-ferrous metals subprogramme of the Commission of the European Communities. In particular from p.171 to 212 is described the recovery of rare earths by supported liquid membranes: synthesis and use of new selective macrocyclic and/or compartmental ligands

  3. Arsenic Encapsulation Using Portland Cement With Ferrous Sulfate/Lime And Terra-BondTM Technologies - Microcharacterization And Leaching Studies

    Science.gov (United States)

    This work reports the results of an investigation on the treatment and encapsulation of arsenic-containing materials by Portland cement with ferrous sulfate and lime (PFL) and Terra-BondTM, a commercially available patented technology. The arsenic materials treated we...

  4. MRI staging of urinary bladder cancer: results using a ferrous contrastographic solution (JKA1)

    International Nuclear Information System (INIS)

    Giovagnoli, A.; Ercolani, P.; De Nigris, E.; Villanova, A.

    1990-01-01

    The authors report the results of the staging of urinary bladder cancers by means of MRI using a new ferrous contrastographic solution called JKA1. Eighteen patients with proved bladder neoplasms were examined by means of MRI: the bladder was filled with physiological solution first, and then with JKA1. Six patients were studied also after filling their bladders with Gd DTPA solution (1:50). The results show that the use of JKA1, a T2-positive contrast medium, improved MR capabilities in the evaluation of small lesions (<1cm in diameter) with minimal invasion of bladder wall; MR staging accuracy was 66.6% with the physiological solution and 77.8% with JKA1. The authors confirm the need for a wider MR study, in particular of T2 lesions (a critical subject for staging and surgical management) to assess MR diagnostic capabilities

  5. Reaction of the H atom in gamma-irradiated ferrous sulphate solutions

    International Nuclear Information System (INIS)

    Mathews, R.W.

    1977-10-01

    The effect of sulphuric acid, ferrous and ferric ion, and oxygen concentrations on G(Fe 3+ ) values from cobalt-60 gamma-irradiated soltuions has been studied. Kinetic expressions were derived for reaction models involving reactions of various forms of the H atom and additional reactions postulated to be of importance at high solute concentration. Three models were assumed invoking the additional reactions: (1) an independent yield of an excited water species; (2) increasing contributions from interspur reactions of well established species at increasing solute concentration; (3) inhibition of charge pair recombination by acid and scavenger species. The calculated G(Fe 3+ ) values from the various models were compared by the least squares method with experimental G(Fe 3+ ) values from over 600 irradiations. Model 3 provided the best fit to the data for the least number of adjustable parameters. No evidence for more than one form of H atom was found with this model. (J.R.)

  6. Magnetic hyperthermia heating of cobalt ferrite nanoparticles prepared by low temperature ferrous sulfate based method

    Directory of Open Access Journals (Sweden)

    Tejabhiram Yadavalli

    2016-05-01

    Full Text Available A facile low temperature co-precipitation method for the synthesis of crystalline cobalt ferrite nanostructures using ferrous sulfate salt as the precursor has been discussed. The prepared samples were compared with nanoparticles prepared by conventional co-precipitation and hydrothermal methods using ferric nitrate as the precursor. X-ray diffraction studies confirmed the formation of cubic spinel cobalt ferrites when dried at 110 °C as opposed to conventional methods which required higher temperatures/pressure for the formation of the same. Field emission scanning electron microscope studies of these powders revealed the formation of nearly spherical nanostructures in the size range of 20-30 nm which were comparable to those prepared by conventional methods. Magnetic measurements confirmed the ferromagnetic nature of the cobalt ferrites with low magnetic remanance. Further magnetic hyperthermia studies of nanostructures prepared by low temperature method showed a rise in temperature to 50 °C in 600 s.

  7. Reversibility in martensitic transformation and shape memory in high Mn ferrous alloys

    International Nuclear Information System (INIS)

    Tomota, Y.

    2000-01-01

    The reversibility of austenite (γ : fcc) epsilon (ε : hcp) martensitic transformation and shape memory effect in high Mn ferrous alloys are discussed. A particular emphasis is put on the ε → γ reverse transformation behavior in two poly-crystalline alloys, Fe-24Mn and Fe-24Mn-6Si, where the latter exhibits excellent shape memory while the former shows poor memory although their forward γ → ε transformation behavior is quite similar. TEM in situ observations have revealed that the motion of Shockley partial dislocations during ε → γ reverse transformation is different from each other in these two alloys. The influence of alloying elements on the shape memory effect can be related to solid solution hardening of austenite, suggesting an important role of internal stress. The effect of training on enhancing the shape memory is explained by such an internal stress distribution associated with the formation of very thin, i.e., nano-scale ε/γ lamellae. (orig.)

  8. Evaluation of commercial grade ferrous ammonium sulfate as potential dosimeter for technological irradiations

    International Nuclear Information System (INIS)

    Juarez-Calderon, J. Manuel; Ramos-Bernal, Sergio; Negron-Mendoza, Alicia

    2008-01-01

    In this work, we have studied the behavior of crystalline ferrous ammonium sulfate (FAS) under gamma irradiation. The doses studied ranged from 33.5 to 270 kGy. The purpose of this study is to explain the setup, measurement, and reporting procedures for using FAS as a dosimeter. The results obtained in the present study show that this salt very easily gave reproducible results, a linear response, as well as, simple sample preparation and reading. The irradiation temperature and dose rate in the response of the iron salt were found to have slight influence. Any storage time up to 18 months resulted in a 36% decreased in the response. The variation in the response obtained for short periods of storage is negligible for this application. Due to the properties of the FAS system also can be use as transfer dosimeter. (author)

  9. [The organization of the comprehensive prevention of urolithiasis among ferrous metallurgy workers].

    Science.gov (United States)

    Egorova, A M

    2009-01-01

    The purpose of study is to evaluate the effectiveness of the set of preventive measures as applied to 321 workers of basic ferrous metallurgy specialties (steel makers, mill men, hot metal shearers). During the clinical examination all the workers were divided on three groups: the workers without any pathology (11.83%, the first group), the workers with metabolic disorders only without urolitiasis (64.81%, the second group) and the workers with urolitiasis diagnosis approved by ultrasonography (23.36%, the third group). The effectiveness of rehabilitation measures was evaluated during half a year (diet therapy, drinking regimen, medicinal plants treatment). After the course of preventive measures was applied the overall health condition of most workers ameliorated and the number of workers with urolitiasis development risk factors reliably decreased up to 6-12%.

  10. Hepatoprotective potential of Azima tetracantha and Tribulus terrestris on ferrous sulfate-induced toxicity in rat

    Directory of Open Access Journals (Sweden)

    Manikandaselvi Sambasivam

    2013-08-01

    Full Text Available The present study is to evaluate the antihepatotoxic effect of hydroalcoholic extract of leaf powder of Azima tetracantha and the fruit powder of Tribulus terrestris. Ferrous sulfate was used to induce hepatotoxicity and Silymarin was used as a standard drug. The level of biochemical parameters such as protein, albumin, globulin, HDL, vitamin E, superoxide dismutase and catalase were observed to be decreased and the level of glucose, LDL, VLDL, bilirubin, cholesterol, triglycerides, alkaline phosphatase and TBARS were increased in hepatotoxicity-induced rats. Retrieval of liver parameters to normal level was obtained after the oral administration of herbal drugs. Histopathological studies revealed diminished hepatocellular injury in the herbal drugs treated rats. As a conclusion hydro alcoholic extract of leaf powder of A. tetracantha and fruit powder of T. terrestris were possesses significant hepatoprotective activity.

  11. Plutonium estimation in the process solutions and oxide dissolved audit samplers by potentiometry using memo titrator

    International Nuclear Information System (INIS)

    Kumaraguru, K.; Shukla, Y.D.; Vijayan, K.; Ramamoorthy, N.; Jambunathan, U.; Kapoor, S.C.

    1990-01-01

    Potentiometric method is employed by using memotitrator coupled with combined electrode for the estimation of plutonium. The estimations are carried out on the process samples and the acid dissolved samples for auditing, in the concentration range of 5 g/l to 20 g/l. The chemical procedure is: i)oxidising plutonium to higher oxidation state by silver oxide, ii)reducing the same by adding excess ferrous, and iii)titrating potassium dichromate against the unreacted ferrous. The plutonium content is computed from ferrous consumed in the reaction. The average percentage error of the method is +/-0.27. The values obtained are in close agreement with those obtained by coulometry. (author)

  12. Mathematical Modelling of the Price Range in the Procurement of Ferrous Scrap by Metallurgical Enterprises

    Directory of Open Access Journals (Sweden)

    Tatyana Aleksandrovna Ivanova

    2018-03-01

    Full Text Available For metallurgical enterprises, it is important to understand the limits of the most probable values of prices and geographical area for procurement of ferrous scrap in the regions. In order to define the maximal scrap prices in the regions, the authors have developed a mathematical model of “auction purchases”. This model equally assesses price competition between scrap consumers. When setting the price, we consider the territorial imbalances between scrap supply and demand in the regions; costs for scrap transportation from supplier to consumer; price level for scrap in the “windows for exports”. We calculate the lowest price according to the “export parity”. The results of the calculations allow evaluating a range of regional prices and interregional flows of scrap. This approach is unnown in the published works of Russian and foreign researchers. For calculations, we have developed a special software. The following initial data were used: data on railroad transportation of ferrous scrap in the Russian Federation provided by JSC Russian Railways; handbooks of railway tariffs 10–01 between railway stations of the Russian Federation; statistical data on prices of 3A metal scrap in the “windows for exports”. The article presents the formal structure of the model of “auction procurement”, the algorithm of its implementation and the results of calculations. The price level calculated according to the model of “auction procurement” can be used in management practice as potentially highest level of price, which can be reached in the conditions of competition between consumers of scrap in a situation when the negotiations are impossible. The proposed mathematical model allows a metallurgical enterprise to prove and implement a differentiated approach to the formation of regional prices of scrap, and to define regions for scrap purchasing.

  13. Aspects of the magnetism of ferrous chloride; Aspects du magnetisme du chlorure ferreux

    Energy Technology Data Exchange (ETDEWEB)

    Carrara, P. [Commissariat a l' Energie Atomique Saclay (France). Centre d' Etudes Nucleaires

    1968-03-01

    This work is a critical review of the existing work on ferrous chloride and presents, as well, a number of new experimental results. First, a careful analysis of the level structure of ferrous ions in the crystalline field shows that the crystalline anisotropy is of the same order of magnitude as the exchange interactions, a feature which gives rise to some particular effects, such as an upward curvature of the magnetization curve at 0 K in a perpendicular magnetic field. Further, the very low temperature (T > 0.4 K) thermal variation of both the specific heat and magnetic susceptibility evidences a magnetic component in elementary excitations. This result suggests the presence of a large magneto-elastic coupling. Finally, an experimental study of the H-T phase diagram near T{sub N} and of the critical behaviour of the specific heat and parallel susceptibility was performed. (author) [French] Ce travail constitue une analyse critique des resultats obtenus a ce jour sur le chlorure ferreux et comporte en outre quelques resultats experimentaux nouveaux. Tout d'abord, une etude precise de la structure de niveaux de l'ion ferreux dans le champ cristallin montre que l'anisotropie cristalline est comparable aux interactions d'echange, ce qui produit quelques effets originaux tels que, par exemple, l'inflexion de la courbe d'aimantation a 0 K en champ perpendiculaire. D'autre part, la variation thermique a basse temperature (T > 0.4 K) de la chaleur specifique et de la susceptibilite magnetique montre la presence d'une composante magnetique dans les excitations de basse energie. Ce resultat suggere la presence d'un couplage magneto-elastique. Enfin, nous avons realise une etude experimentale de la ligne de transition de phase (diagramme H,T) au voisinage de T{sub N}, et du comportement critique de la chaleur specifique et de la susceptibilite parallele. (auteur)

  14. Overview of the long distance iron ore slurry pipeline from Anglo Ferrous Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Adarlan M.; Passos, Aline C.; Santos, Daniel; Orban, Eduardo M.; Lisboa, Helder D.; Goncalves, Nilton; Guimaraes, Robson C. [Anglo Ferrous Brazil, Rio de Janeiro, RJ (Brazil)

    2009-07-01

    The objective of this paper is to present an overview of the long distance iron ore slurry pipeline from Anglo Ferrous Brazil. Anglo Ferrous Brazil is a company of Anglo American plc that is one of the world's largest mining and natural resource company. Minas-Rio is a world class iron ore project which has been developed in Brazil aiming to produce 26.6 million tons per year of concentrate. The mine, concentrator and pump station 1 will be located in Conceicao do Mato Dentro, Minas Gerais state, and the terminal station will be located at Acu Port in Sao Joao da Barra, Rio de Janeiro state. The long distance iron ore slurry pipeline will be one of major differentials of Minas-Rio Project and its useful life was initially estimated in 20 years. The slurry pipeline has a total length of 525 kilometers and will be constructed from predominately 26 inches external diameter API 5L X70 pipes. From kilometer 314 to kilometer 480, 24 inches pipe will be installed to prevent slack flow downstream pump station 2. The pump station 1 is designed to provide the hydraulic head necessary to transport the concentrate iron ore slurry with 8 positive displacement pumps to pump station 2. The pump station 2, located 240 kilometers downstream pump station 1, is designed to operate with 10 positive displacement pumps. The valve station will be located at kilometer 347 and will be used to break the static head between pump station 2 and the terminal station during a slurry pipeline shutdown. (author)

  15. German experience in recycling of ferrous metallic residues from nuclear decommissioning by melting

    International Nuclear Information System (INIS)

    Quade, U.; Kluth, Th.

    2008-01-01

    Due to the delay of commissioning of final depositories for nuclear waste on the one hand and the increasing amount of steel scrap resulting from operation and decommissioning of nuclear facilities on the other hand, recycling of ferrous metal scrap to packagings made of ductile cast iron becomes more and more economical. A pool of know-how from waste managers, radiation protection experts, metallurgists and foundry experts and their teamwork is required to run this recycling path successfully. Siempelkamp provides this combination of experience by operating a melting facility for slightly radioactive contaminated scrap as well as a foundry for manufacturing of ductile cast iron products for the nuclear industry, both licensed by the German Radiation Protection Ordinance. In 1989, the CARLA plant (Centrale Anlage zum Rezyklieren von leichtradioaktiven Abfollen) started operation. A medium frequency induction furnace with a capacity of 3,2 t is core of the plant. Tools for dismantling and cutting components to chargeable sizes are available. From the total of 23000 t of melted scrap, 12000 t have been recycled to the manufacturing of containers for transport and storage of medium- and high active waste and for shielding plates. Manufacture of the castings takes place in the Siempelkamp foundry located at the same site. 8000 t of melted scrap could be released for industrial recycling. Scrap metal which does not meet the metallurgical specification for cast iron, is converted into iron granules. Up to now more than 2000 t of iron granules have been recycled as additive for heavy concrete containers. This production is in cooperation with an external partner. With regard to the German situation, the cost for recycling is only half compared to high pressure compaction, long-term interim storage and final disposal. The advantage of recycling is approx. 90 % less volume compared to the volume resulting from other disposal paths. It can be concluded that the German

  16. A Metallurgical Investigation of the Direct Energy Deposition Surface Repair of Ferrous Alloys

    Science.gov (United States)

    Marya, Manuel; Singh, Virendra; Hascoet, Jean-Yves; Marya, Surendar

    2018-02-01

    Among additive manufacturing (AM) processes, the direct energy deposition (DED) by laser is explored to establish its applicability for the repair of ferrous alloys such as UNS G41400 low-alloy steel, UNS S41000 martensitic stainless steel, UNS S17400 precipitation-strengthened martensitic stainless steel, and UNS S32750 super-duplex stainless steel. Unlike plating, thermal spray, and conventional cladding weld, DED laser powder deposition offers potential advantages, e.g., thin deposits, limited dilutions, narrow heat-affected zones (HAZ), potentially improved surface properties. In this investigation, all AM deposits were completed with an IREPA CLAD™ system using a powder feed of UNS N06625, an alloy largely selected for its outstanding corrosion resistance. This investigation first addresses topological aspects of AM deposits (including visual imperfections) before focusing on changes in microstructure, microhardness, chemical composition across AM deposits and base materials. It has been established that dense, uniform, hard ( 300 HVN), crack-free UNS N06625-compliant AM deposits of fine dendritic microstructures are reliably produced. However, except for the UNS S32750 steel, a significant martensitic hardening was observed in the HAZs of UNS G41400 ( 650 HVN), UNS S41000 ( 500 HVN), and UNS S17400 ( 370 HVN). In summary, this investigation demonstrates that the DED laser repair of ferrous parts with UNS N06625 may restore damaged surfaces, but it also calls for cautions and complementary investigations for alloys experiencing a high HAZ hardening, for which industry standard recommendations are exceeded and lead to an increased risk of delayed cracking in corrosive environments.

  17. Monomer-dimer equilibrium and oxygen binding properties of ferrous Vitreoscilla hemoglobin.

    Science.gov (United States)

    Giangiacomo, L; Mattu, M; Arcovito, A; Bellenchi, G; Bolognesi, M; Ascenzi, P; Boffi, A

    2001-08-07

    The monomer-dimer equilibrium and the oxygen binding properties of ferrous recombinant Vitreoscilla hemoglobin (Vitreoscilla Hb) have been investigated. Sedimentation equilibrium data indicate that the ferrous deoxygenated and carbonylated derivatives display low values of equilibrium dimerization constants, 6 x 10(2) and 1 x 10(2) M(-1), respectively, at pH 7.0 and 10 degrees C. The behavior of the oxygenated species, as measured in sedimentation velocity experiments, is superimposable to that of the carbonylated derivative. The kinetics of O(2) combination, measured by laser photolysis at pH 7.0 and 20 degrees C, is characterized by a second-order rate constant of 2 x 10(8) M(-1) s(-1) whereas the kinetics of O(2) release at pH 7.0 is biphasic between 10 and 40 degrees C, becoming essentially monophasic below 10 degrees C. Values of the first-order rate constants (at 20 degrees C) and of the activation energies for the fast and slow phases of the Vitreoscilla Hb deoxygenation process are 4.2 s(-1) and 19.2 kcal mol(-1) and 0.15 s(-1) and 24.8 kcal mol(-1), respectively. Thus the biphasic kinetics of Vitreoscilla Hb deoxygenation is unrelated to the association state of the protein. The observed biphasic oxygen release may be accounted for by the presence of two different conformers in thermal equilibrium within the monomer. The two conformers may be assigned to a structure in which the heme-iron-bound ligand is stabilized by direct hydrogen bonding to TyrB10 and a structure in which such interaction is absent. The slow interconversion between the two conformers may reflect a very large conformational rearrangement in the disordered distal pocket segment connecting helices C and E.

  18. Ferrous sulfate supplementation causes significant gastrointestinal side-effects in adults: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Zoe Tolkien

    Full Text Available The tolerability of oral iron supplementation for the treatment of iron deficiency anemia is disputed.Our aim was to quantify the odds of GI side-effects in adults related to current gold standard oral iron therapy, namely ferrous sulfate.Systematic review and meta-analysis of randomized controlled trials (RCTs evaluating GI side-effects that included ferrous sulfate and a comparator that was either placebo or intravenous (i.v. iron. Random effects meta-analysis modelling was undertaken and study heterogeneity was summarised using I2 statistics.Forty three trials comprising 6831 adult participants were included. Twenty trials (n = 3168 had a placebo arm and twenty three trials (n = 3663 had an active comparator arm of i.v. iron. Ferrous sulfate supplementation significantly increased risk of GI side-effects versus placebo with an odds ratio (OR of 2.32 [95% CI 1.74-3.08, p<0.0001, I2 = 53.6%] and versus i.v. iron with an OR of 3.05 [95% CI 2.07-4.48, p<0.0001, I2 = 41.6%]. Subgroup analysis in IBD patients showed a similar effect versus i.v. iron (OR = 3.14, 95% CI 1.34-7.36, p = 0.008, I2 = 0%. Likewise, subgroup analysis of pooled data from 7 RCTs in pregnant women (n = 1028 showed a statistically significant increased risk of GI side-effects for ferrous sulfate although there was marked heterogeneity in the data (OR = 3.33, 95% CI 1.19-9.28, p = 0.02, I2 = 66.1%. Meta-regression did not provide significant evidence of an association between the study OR and the iron dose.Our meta-analysis confirms that ferrous sulfate is associated with a significant increase in gastrointestinal-specific side-effects but does not find a relationship with dose.

  19. Ferrous sulfate supplementation causes significant gastrointestinal side-effects in adults: a systematic review and meta-analysis.

    Science.gov (United States)

    Tolkien, Zoe; Stecher, Lynne; Mander, Adrian P; Pereira, Dora I A; Powell, Jonathan J

    2015-01-01

    The tolerability of oral iron supplementation for the treatment of iron deficiency anemia is disputed. Our aim was to quantify the odds of GI side-effects in adults related to current gold standard oral iron therapy, namely ferrous sulfate. Systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating GI side-effects that included ferrous sulfate and a comparator that was either placebo or intravenous (i.v.) iron. Random effects meta-analysis modelling was undertaken and study heterogeneity was summarised using I2 statistics. Forty three trials comprising 6831 adult participants were included. Twenty trials (n = 3168) had a placebo arm and twenty three trials (n = 3663) had an active comparator arm of i.v. iron. Ferrous sulfate supplementation significantly increased risk of GI side-effects versus placebo with an odds ratio (OR) of 2.32 [95% CI 1.74-3.08, p<0.0001, I2 = 53.6%] and versus i.v. iron with an OR of 3.05 [95% CI 2.07-4.48, p<0.0001, I2 = 41.6%]. Subgroup analysis in IBD patients showed a similar effect versus i.v. iron (OR = 3.14, 95% CI 1.34-7.36, p = 0.008, I2 = 0%). Likewise, subgroup analysis of pooled data from 7 RCTs in pregnant women (n = 1028) showed a statistically significant increased risk of GI side-effects for ferrous sulfate although there was marked heterogeneity in the data (OR = 3.33, 95% CI 1.19-9.28, p = 0.02, I2 = 66.1%). Meta-regression did not provide significant evidence of an association between the study OR and the iron dose. Our meta-analysis confirms that ferrous sulfate is associated with a significant increase in gastrointestinal-specific side-effects but does not find a relationship with dose.

  20. Arsenic encapsulation using Portland cement with ferrous sulfate/lime and Terra-Bond™ technologies - Microcharacterization and leaching studies.

    Science.gov (United States)

    Randall, Paul M

    2012-03-15

    This work reports the results of an investigation on the treatment and encapsulation of arsenic-containing materials by Portland cement with ferrous sulfate and lime (PFL) and Terra-Bond™, a commercially available patented technology. The arsenic materials included: chromated copper arsenate (CCA)-treated wood materials; scorodite-rich mine tailings from the La Trinidad Mine in California; and a soil/smelter dust mixture from the Anaconda Superfund site spiked with monosodium methyl arsenate (MSMA) to simulate an organoarsenic soil material. SEM/EDS and XRD spectra of PFL treated samples showed similarity across all three waste materials while Terra-Bond treated samples showed predominance of elemental sulfur. SEM/EDS of PFL treated samples showed that calcium was imbedded in the structure while micrographs of Terra-Bond treated samples showed the appearance of an epoxy material on the surface. The epoxy material appears to be responsible for encapsulating and reducing the leachability of arsenic. XANES spectra for the PFL treatment of CCA-containing samples showed that arsenic has a predominant pentavalent form (As +5), and the PFL treatment process did not alter the arsenic oxidation state. But, distinct differences were observed for XANES spectra of untreated and PFL treated scorodite-rich mine tailing which changed the arsenic coordination structure from a mixture of As (+3/+5) to exclusively As (+5). Both S/S techniques reduced the amount of arsenic released in the leaching tests. Most cases show lower amounts of arsenic released from wastes treated by the Terra-Bond™ technique when compared to the PFL technique. The pH of the solution significantly affected the leachability, with the amount of arsenic released increasing with pH. Sequential extraction results indicate that sodium hydroxide was favorable in releasing arsenic in the mine tailings. This is due to ligand displacement reactions of hydroxyl ions with arsenic species and high pH conditions that

  1. The ferrous ammonium sulfate solid system, as dosemeter for processes at low temperatures and high doses of gamma radiation; El sistema sulfato ferroso amoniacal solido, como dosimetro para procesos a bajas temperaturas y altas dosis de radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Juarez C, J.M.; Ramos B, S.; Negron M, A. [ICN-UNAM, 04510 Mexico D.F. (Mexico)

    2005-07-01

    This paper presents the results obtained from a study of the radiation induced oxidation of crystalline ferrous ammonium sulfate with gamma rays at 295 K, 263 K and 77 K and dose from 0 to 300 kGy. The radiation induced decomposition of ferrous ammonium sulfate has been studied by the dissolution of the irradiated salt in 0,8 N sulfuric acid. The main product is Fe{sup 3+} and molar concentration of ferric ion was determined spectrophotometrically in the UV region at 304 nm. The optical density values showed a linear dependence with dose, indicating that the data obtained might be used to create a calibrating curve. Color in irradiated salt changes from blue to green, yellow and orange according to the absorbed dose. The accuracy and the reproducibility of the system were tested. In addition, some other characteristics make possible the use of this system as a dosimeter, similar to Fricke chemical dosemeter, at low temperatures and high dose. (Author)

  2. The PerR-Regulated P1B-4-Type ATPase (PmtA) Acts as a Ferrous Iron Efflux Pump in Streptococcus pyogenes.

    Science.gov (United States)

    Turner, Andrew G; Ong, Cheryl-Lynn Y; Djoko, Karrera Y; West, Nicholas P; Davies, Mark R; McEwan, Alastair G; Walker, Mark J

    2017-06-01

    Streptococcus pyogenes (group A Streptococcus [GAS]) is an obligate human pathogen responsible for a broad spectrum of human disease. GAS has a requirement for metal homeostasis within the human host and, as such, tightly modulates metal uptake and efflux during infection. Metal acquisition systems are required to combat metal sequestration by the host, while metal efflux systems are essential to protect against metal overload poisoning. Here, we investigated the function of PmtA ( P erR-regulated m etal t ransporter A ), a P 1B-4 -type ATPase efflux pump, in invasive GAS M1T1 strain 5448. We reveal that PmtA functions as a ferrous iron [Fe(II)] efflux system. In the presence of high Fe(II) concentrations, the 5448Δ pmtA deletion mutant exhibited diminished growth and accumulated 5-fold-higher levels of intracellular Fe(II) than did the wild type and the complemented mutant. The 5448Δ pmtA deletion mutant also showed enhanced susceptibility to killing by the Fe-dependent antibiotic streptonigrin as well as increased sensitivity to hydrogen peroxide and superoxide. We suggest that the PerR-mediated control of Fe(II) efflux by PmtA is important for bacterial defense against oxidative stress. PmtA represents an exemplar for an Fe(II) efflux system in a host-adapted Gram-positive bacterial pathogen. Copyright © 2017 American Society for Microbiology.

  3. Humic acids enhance the microbially mediated release of sedimentary ferrous iron.

    Science.gov (United States)

    Chang, Chun-Han; Wei, Chia-Cheng; Lin, Li-Hung; Tu, Tzu-Hsuan; Liao, Vivian Hsiu-Chuan

    2016-03-01

    Iron (Fe) is an essential element for many organisms, but high concentrations of iron can be toxic. The complex relation between iron, arsenic (As), bacteria, and organic matter in sediments and groundwater is still an issue of environmental concern. The present study addresses the effects of humic acids and microorganisms on the mobilization of iron in sediments from an arsenic-affected area, and the microbial diversity was analyzed. The results showed that the addition of 50, 100, and 500 mg/L humic acids enhanced ferrous iron (Fe(II)) release in a time-dependent and dose-dependent fashion under anaerobic conditions. A significant increase in the soluble Fe(II) concentrations occurred in the aqueous phases of the samples during the first 2 weeks, and aqueous Fe(II) reached its maximum concentrations after 8 weeks at the following Fe(II) concentrations: 28.95 ± 1.16 mg/L (original non-sterilized sediments), 32.50 ± 0.71 mg/L (50 mg/L humic acid-amended, non-sterilized sediments), 37.50 ± 1.85 mg/L (100 mg/L humic acid-amended, non-sterilized sediments), and 39.00 ± 0.43 mg/L (500 mg/L humic acid-amended, non-sterilized sediments). These results suggest that humic acids can further enhance the microbially mediated release of sedimentary iron under anaerobic conditions. By contrast, very insignificant amounts of iron release were observed from sterilized sediments (the abiotic controls), even with the supplementation of humic acids under anaerobic incubation. In addition, the As(III) release was increased from 50 ± 10 μg/L (original non-sterilized sediments) to 110 ± 45 μg/L (100 mg/L humic acid-amended, non-sterilized sediments) after 8 weeks of anaerobic incubation. Furthermore, a microbial community analysis indicated that the predominant class was changed from Alphaproteobacteria to Deltaproteobacteria, and clearly increased populations of Geobacter sp., Paludibacter sp., and Methylophaga sp. were found after adding humic acids

  4. Neutrophilic iron-oxidizing bacteria: occurrence and relevance in biological drinking water treatment

    DEFF Research Database (Denmark)

    Gülay, Arda; Musovic, Sanin; Albrechtsen, Hans-Jørgen

    2013-01-01

    Rapid sand filtration (RSF) is an economical way to treat anoxic groundwater around the world. It consists of groundwater aeration followed by passage through a sand filter. The oxidation and removal of ferrous iron, which is commonly found in anoxic groundwaters, is often believed to be a fully ...... role of FeOB in iron removal at waterworks using RSF technologies....

  5. Spatial patterns of iron- and methane-oxidizing bacterial communities in an irregularly flooded, riparian wetland

    NARCIS (Netherlands)

    Wang, J.; Krause, S.; Muyzer, Gerard; Meima-Franke, M.; Laanbroek, H.J.; Bodelier, P.L.E.

    2012-01-01

    Iron- and methane-cycling are important processes in wetlands with one connected to plant growth and the other to greenhouse gas emission, respectively. In contrast to acidic habitats, there is scarce information on the ecology of microbes oxidizing ferrous iron at circum-neutral pH. The latter is

  6. Spatial patterns of iron- and methane-oxidizing bacterial communities in an irregularly flooded, riparian wetland

    NARCIS (Netherlands)

    Wang, J.; Krause, S.; Muyzer, G.; Meima-Franke, M.; Laanbroek, H.J.; Bodelier, P.L.E.

    2012-01-01

    Iron- and methane-cycling are important processes in wetlands with one connected to plant growth and the other to greenhouse gas emission, respectively. In contrast to acidic habitats, there is scarce information on the ecology of microbes oxidizing ferrous iron at circumneutral pH. The latter is

  7. Neutrophilic Iron Oxidizing Bacteria: Occurrence and Relevance in Biological Drinking Water Treatment

    DEFF Research Database (Denmark)

    Gülay, Arda; Musovic, Sanin; Albrechtsen, Hans-Jørgen

    Rapid sand filtration (RSF) is an economical way to treat anoxic groundwater around the world. It consists of groundwater aeration followed by passage through a sand filter. The oxidation and removal of ferrous iron, which is commonly found in anoxic groundwaters, is often believed to be a fully......, neutrophilic iron oxidizers were present at the level of up to 7 105 cells per gram sediment. The spatial abundance and diversity of FeOB inferred by DGGE fingerprinting differed greatly both between and within individual sand filters. The results suggest a larger than assumed role of FeOB in iron removal...... physicochemical process. However, persistently low temperatures in RSF across Denmark may negatively affect the kinetics of chemical oxidation. The slower chemical oxidation of ferrous iron may increase the chances for iron bioconversion by neutrophilic iron-oxidizing bacteria (FeOB), which are found naturally...

  8. Preparation of ferrous chelate of hairtail (Trichiurus haumela) protein hydrolysate (Fe(II)-HPH) and its antibacterial activity

    Science.gov (United States)

    Lin, Huimin; Zhang, Bin; Yu, Tian; Deng, Shanggui

    The preparation of a ferrous chelate of hairtail (Trichiurus haumela) protein hydrolysate (Fe(II)-HPH) and its antibacterial activity were studied. The optimal conditions of hydrolysis by papain and ferrous chelation were obtained by single-factor experiments and orthogonal test, with the antibacterial activities as the index. In addition, the antibacterial activity of Fe(II)-HPH was evaluated using the Plackett-Burman design. The orthogonal test results showed that Fe(II)-HPH had an antibacterial activity of 98.3% under a temperature of 40 °C at pH 6.5 for an enzymolysis duration of eight hours in the presence of 20,000 U/g of enzyme. The Plackett-Burman design analysis showed that the three most significant factors (P < 0.05) influencing the antibacterial activity of Fe(II)-HPH were pH, the concentration (mg/mL), and presence of magnesium sulfate.

  9. Chromium content in human skin after in vitro application of ordinary cement and ferrous-sulphate-reduced cement

    DEFF Research Database (Denmark)

    Fullerton, A; Gammelgaard, Bente; Avnstorp, C

    1993-01-01

    The amount of chromium found in human skin after in vitro application of cement suspensions on full-thickness human skin in diffusion cells was investigated. Cement suspensions made from ordinary Portland cement or Portland cement with the chromate reduced with added ferrous sulphate were used....... The cement suspensions were either applied on the skin surface under occlusion for 48 h or applied repeatedly every 24 h for 96 h. No statistically significant difference in chromium content of skin layers between skin exposed to ordinary Portland cement, skin exposed to cement with added ferrous sulphate...... and unexposed skin was observed, despite a more permeable skin barrier at the alkaline pH of the cement suspensions, i.e., pH 12.5. Increased chromium levels in epidermis and dermis were seen when ordinary Portland cement was applied as a suspension with added sodium sulphate (20%) on the skin surface for 96 h...

  10. Alginate inhibits iron absorption from ferrous gluconate in a randomized controlled trial and reduces iron uptake into Caco-2 cells.

    Directory of Open Access Journals (Sweden)

    Anna A Wawer

    Full Text Available Previous in vitro results indicated that alginate beads might be a useful vehicle for food iron fortification. A human study was undertaken to test the hypothesis that alginate enhances iron absorption. A randomised, single blinded, cross-over trial was carried out in which iron absorption was measured from serum iron appearance after a test meal. Overnight-fasted volunteers (n = 15 were given a test meal of 200 g cola-flavoured jelly plus 21 mg iron as ferrous gluconate, either in alginate beads mixed into the jelly or in a capsule. Iron absorption was lower from the alginate beads than from ferrous gluconate (8.5% and 12.6% respectively, p = 0.003. Sub-group B (n = 9 consumed the test meals together with 600 mg calcium to determine whether alginate modified the inhibitory effect of calcium. Calcium reduced iron absorption from ferrous gluconate by 51%, from 11.5% to 5.6% (p = 0.014, and from alginate beads by 37%, from 8.3% to 5.2% (p = 0.009. In vitro studies using Caco-2 cells were designed to explore the reasons for the difference between the previous in vitro findings and the human study; confirmed the inhibitory effect of alginate. Beads similar to those used in the human study were subjected to simulated gastrointestinal digestion, with and without cola jelly, and the digestate applied to Caco-2 cells. Both alginate and cola jelly significantly reduced iron uptake into the cells, by 34% (p = 0.009 and 35% (p = 0.003 respectively. The combination of cola jelly and calcium produced a very low ferritin response, 16.5% (p < 0.001 of that observed with ferrous gluconate alone. The results of these studies demonstrate that alginate beads are not a useful delivery system for soluble salts of iron for the purpose of food fortification.ClinicalTrials.gov NCT01528644.

  11. The maturation state of the auditory nerve and brainstem in rats exposed to lead acetate and supplemented with ferrous sulfate.

    Science.gov (United States)

    Zucki, Fernanda; Morata, Thais C; Duarte, Josilene L; Ferreira, Maria Cecília F; Salgado, Manoel H; Alvarenga, Kátia F

    The literature has reported the association between lead and auditory effects, based on clinical and experimental studies. However, there is no consensus regarding the effects of lead in the auditory system, or its correlation with the concentration of the metal in the blood. To investigate the maturation state of the auditory system, specifically the auditory nerve and brainstem, in rats exposed to lead acetate and supplemented with ferrous sulfate. 30 weanling male rats (Rattus norvegicus, Wistar) were distributed into six groups of five animals each and exposed to one of two concentrations of lead acetate (100 or 400mg/L) and supplemented with ferrous sulfate (20mg/kg). The maturation state of the auditory nerve and brainstem was analyzed using Brainstem Auditory Evoked Potential before and after lead exposure. The concentration of lead in blood and brainstem was analyzed using Inductively Coupled Plasma-Mass Spectrometry. We verified that the concentration of Pb in blood and in brainstem presented a high correlation (r=0.951; p<0.0001). Both concentrations of lead acetate affected the maturation state of the auditory system, being the maturation slower in the regions corresponding to portion of the auditory nerve (wave I) and cochlear nuclei (wave II). The ferrous sulfate supplementation reduced significantly the concentration of lead in blood and brainstem for the group exposed to the lowest concentration of lead (100mg/L), but not for the group exposed to the higher concentration (400mg/L). This study indicate that the lead acetate can have deleterious effects on the maturation of the auditory nerve and brainstem (cochlear nucleus region), as detected by the Brainstem Auditory Evoked Potentials, and the ferrous sulphate can partially amend this effect. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. All rights reserved.

  12. Electronic environments of ferrous iron in rhyolitic and basaltic glasses at high pressure: Silicate Glasses at High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Solomatova, Natalia V. [Division of Geological and Planetary Sciences, Caltech, Pasadena California USA; Jackson, Jennifer M. [Division of Geological and Planetary Sciences, Caltech, Pasadena California USA; Sturhahn, Wolfgang [Division of Geological and Planetary Sciences, Caltech, Pasadena California USA; Rossman, George R. [Division of Geological and Planetary Sciences, Caltech, Pasadena California USA; Roskosz, Mathieu [IMPMC-Muséum National d' Histoire Naturelle-CNRS, Paris France

    2017-08-01

    The physical properties of silicate melts within Earth's mantle affect the chemical and thermal evolution of its interior. Chemistry and coordination environments affect such properties. We have measured the hyperfine parameters of iron-bearing rhyolitic and basaltic glasses up to ~120 GPa and ~100 GPa, respectively, in a neon pressure medium using time domain synchrotron Mössbauer spectroscopy. The spectra for rhyolitic and basaltic glasses are well explained by three high-spin Fe2+-like sites with distinct quadrupole splittings. Absence of detectable ferric iron was confirmed with optical absorption spectroscopy. The sites with relatively high and intermediate quadrupole splittings are likely a result of fivefold and sixfold coordination environments of ferrous iron that transition to higher coordination with increasing pressure. The ferrous site with a relatively low quadrupole splitting and isomer shift at low pressures may be related to a fourfold or a second fivefold ferrous iron site, which transitions to higher coordination in basaltic glass, but likely remains in low coordination in rhyolitic glass. These results indicate that iron experiences changes in its coordination environment with increasing pressure without undergoing a high-spin to low-spin transition. We compare our results to the hyperfine parameters of silicate glasses of different compositions. With the assumption that coordination environments in silicate glasses may serve as a good indicator for those in a melt, this study suggests that ferrous iron in chemically complex silicate melts likely exists in a high-spin state throughout most of Earth's mantle.

  13. Natural analogues for expansion due to the anaerobic corrosion of ferrous materials

    Energy Technology Data Exchange (ETDEWEB)

    Smart, N.R.; Adams, R. [Serco Assurance, Culham Science Centre (United Kingdom)

    2006-10-15

    In Sweden, spent nuclear fuel will be encapsulated in sealed cylindrical canisters, consisting of a cast iron insert and a copper outer container. The canisters will be placed in a deep geologic repository and surrounded by bentonite. If a breach of the outer copper container were to occur the cast iron insert would undergo anaerobic corrosion, forming a magnetite film whose volume would be greater than that of the base metal. In principle there is a possibility that accumulation of iron corrosion product could cause expansion of the copper canister. Anaerobic corrosion rates are very slow, so in the work described in this report reference was made to analogous materials that had been corroding for long periods in natural anoxic aqueous environments. The report considers the types of naturally occurring environments that may give rise to anoxic environments similar to deep geological groundwater and where ferrous materials may be found. Literature information regarding the corrosion of iron archaeological artefacts is summarised and a number of specific archaeological artefacts containing iron and copper corroding in constrained geometries in anoxic natural waters are discussed in detail. No evidence was obtained from natural analogues which would suggest that severe damage is likely to occur to the SKB waste canister design as a result of expansive corrosion of cast iron under repository conditions.

  14. Natural analogues for expansion due to the anaerobic corrosion of ferrous materials

    International Nuclear Information System (INIS)

    Smart, N.R.; Adams, R.

    2006-10-01

    In Sweden, spent nuclear fuel will be encapsulated in sealed cylindrical canisters, consisting of a cast iron insert and a copper outer container. The canisters will be placed in a deep geologic repository and surrounded by bentonite. If a breach of the outer copper container were to occur the cast iron insert would undergo anaerobic corrosion, forming a magnetite film whose volume would be greater than that of the base metal. In principle there is a possibility that accumulation of iron corrosion product could cause expansion of the copper canister. Anaerobic corrosion rates are very slow, so in the work described in this report reference was made to analogous materials that had been corroding for long periods in natural anoxic aqueous environments. The report considers the types of naturally occurring environments that may give rise to anoxic environments similar to deep geological groundwater and where ferrous materials may be found. Literature information regarding the corrosion of iron archaeological artefacts is summarised and a number of specific archaeological artefacts containing iron and copper corroding in constrained geometries in anoxic natural waters are discussed in detail. No evidence was obtained from natural analogues which would suggest that severe damage is likely to occur to the SKB waste canister design as a result of expansive corrosion of cast iron under repository conditions

  15. Characterization of naturally occurring radioactive materials and Cobald-60 contaminated ferrous scraps from steel industries

    International Nuclear Information System (INIS)

    Chao, H.E.; Chiu, H.S.; Hunga, J.Y.; His, H.W.; Chen, Y.B.

    2002-01-01

    Since the occurrence of radioactively contaminated rebar incident in 1992, steel industries in Taiwan were encouraged by Atomic Energy Council (AEC) to install portal monitor to detect the abnormal radiation in shipments of metal scrap feed. From 1994 through 1999, there were 53 discoveries of radioactivity in ferrous scraps by steel companies. These include 15 orphan radioactive sources, 16 cobalt-60 contaminated rebars, 20 Naturally Occurring Radioactive Material (NORM) contaminated scraps, and two unknowns. Most NORM-contaminated scraps were from abroad. The NORM and cobalt-60 contaminated scraps were taken from the steel mills and analyzed in laboratory. The analytical results of scales and sludge sampled from NORM-contaminated scraps combining with the circumstantial evidences indicate that five possible industrial processes may be involved. They are oil production and treatment, heavy mineral sand benefication and rare earth processing, copper mining and processing, recovery of ammonium chloride by lime adsorption in Ammonium-soda process, and tailing of uranium enrichment process. The cobalt-60 activity and trace elements concentrations of contaminated rebars confirm that all of them were produced domestically in the period from Oct. 1982 to Jan. 1983, when the cobalt-60 sources were lost and entered the electric arc furnace to produce the contaminated rebars. (author)

  16. On the characterisation of the corrosion layout of ferrous archaeological analogues in binders

    International Nuclear Information System (INIS)

    Chitty, Walter-John; Dillmann, Philippe; L'Hostis, Valerie; Beranger, Gerard

    2004-01-01

    This paper deals with an analytical study on ferrous reinforcements embedded in hydraulic binders found in ancient buildings from the Middle Age period to the beginning of the 20. c. AD. The study of these kind of archaeological analogues is necessary to improve the knowledge on the long-term corrosion of low carbon steels that could be used in concrete to build the substructure of nuclear wastes reversible storage facilities. The corrosion system can be described as a multi-layer pattern made of the metal, a dense corrosion product layer, a transformed medium and a binder. All the morphological and physicochemical properties as composition, structure and porosities of these different parts were studied with different analytical methods as optical and electron microscopy, EDS coupled to SEM, EPMA, mercury porosimetry, micro Raman spectroscopy and micro Diffraction under Synchrotron Radiation. Moreover, average corrosion rates were evaluated by two different methods. These rates are relatively low compared to the same parameters measured on low alloyed steels immersed in aqueous environments and are comparable with results obtained for passivated systems. (authors)

  17. Surface treatment of non-ferrous metals for the purpose of gas analysis

    International Nuclear Information System (INIS)

    Quaglia, L.; Weber, G.; Triffaux, J.; Geerts, J.; Audenhove, J. van; Pauwels, J.

    1979-01-01

    The present report is an updating of earlier reports published in 1972 and 1976. Its major improvement compared to the earlier reports is that greater importance has been devoted to quantify the parameters of mechanical shaping techniques to be used with or without subsequent chemical etching. Surface treatments have been studied and standardized for a number of non-ferrous metals. Recommendations were generally made on the basis of the following: the proposed treatment must give a minimum surface content; it must exhibit good reproducibility; it must be easy to perform with equipment normally available in analytical laboratories. The recommended treatments are presented in the form of sheets. They give full information on mechanica shaping parameters if these are important, and -if needed- the subsequent chemical etching conditions. Typical residual surface contents are given for oxygen carbon and nitrogen. They refer to samples freshly prepared. The metals or alloys concerned are: aluminium, aluminium alloyed with 3%, 7% and 13% silicon, copper, lead, nickel, titanium, TiAl 6 V 4 zirconium, tungsten and molybdenum

  18. Stress Analysis of Non-Ferrous Metals Welds by Numerical Simulation

    Directory of Open Access Journals (Sweden)

    Kravarikova Helena

    2017-01-01

    Full Text Available Thermal energy welded material unevenly heated and thus supports the creation of tension. During the fusing process welding transient tensions generated in the welded material. Generation of the transient tensions depends on the thermal expansion and fixed permanently welded parts. Tensions are the result of the interaction of material particles. For welded parts and constructions it is necessary to know the size and direction of application of tensions. The emerging tensions can cause local change or a total deformation of welded materials. Deformations and residual stresses impair the performance of a welded construction, reduces the stability of the parts. To reduce or eliminate of action or a screening direction stresses and strains it is necessary to know the mechanism of their emergence. It is now possible to examine the emergence of tensions numerical experiments on any model using numerical simulation using FEM. Results of numerical experiment is the analysis of stress and deformation course. In the plane the tension it divided into normal σ and τ tangential folders. Decomposition stress on components simplifies the stress analysis. The results obtained from numerical analysis are correct to predict the stress distribution and size. The paper presents the results of numerical experiments stress analysis solutions fillet welds using FEM numerical simulation of welding of non-ferrous metals.

  19. Effect of ferrous sulphate on haematological, biochemical and immunological parameters in neonatal calves

    Directory of Open Access Journals (Sweden)

    Lobna S. Elgebaly

    2010-09-01

    Full Text Available The effect of oral administration of iron on haematological, biochemical and immunological parameters in neonatal calves was studied. Ten calves from a private farm in Gharbia Governorate were used. Calves were separated from their dams immediately after birth and received colostrum during the first hours after calving and twice daily for 48 h. Thereafter, they received whole milk. Calves were divided into two equal groups. The first group was kept as controls. Calves of the second group were given ferrous sulphate at a dose of 250 mg/calf daily, beginning at one day of age; this was continued for 28 days. Three blood samples were collected from each calf in all groups at 14, 21, 28 and 35 days of age. Iron administration produced a significant increase in red blood cell count, haemoglobin, packed cell volume and blood indices, in addition to non-significant changes in total and differential leukocyte counts. The administration of iron resulted in a significant increase in serum iron, total proteins, globulins, thyroid hormones, lymphocyte stimulation index, phagocytosis, body weight and body gain. The administration of iron is suggested as routine practice in calf-producing farms due to its advantageous effects on the parameters tested.

  20. Improvement of the Wear Resistance of Ferrous Alloys by Electroless Plating of Nickel

    Science.gov (United States)

    Kaleicheva, J. K.; Karaguiozova, Z.

    2018-01-01

    The electroless nickel (Ni) and composite nickel - nanodiamond (Ni+DND) coatings are investigated in this study. The method EFTTOM-NICKEL for electroless nickel plating with nanosized strengthening particles (DND 4-6 nm) is applied for the coating deposition. The coatings are deposited on ferrous alloys samples. The wear resistance of the coatings is performed by friction wear tests under 50-400 MPa loading conditions - in accordance with a Polish Standard PN-83/H-04302. The microstructure observations are made by optic metallographic microscope GX41 OLIMPUS and the microhardness is determined by Vickers Method. Tests for wear resistance, thickness and microhardness measurements of the coatings without heat treatment and heat treatment are performed. The heat treatment regime is investigated with the aim to optimize the thermal process control of the coated samples without excessive tempering of the substrate material. The surface fatigue failure is determined by contact fatigue test with the purpose to establish suitable conditions for production of high performance materials.

  1. Effect of ferrous sulfate fortification in germinated brown rice on seed iron concentration and bioavailability.

    Science.gov (United States)

    Wei, Yanyan; Shohag, M J I; Ying, Feng; Yang, Xiaoe; Wu, Chunyong; Wang, Yuyan

    2013-06-01

    The present study evaluated the effectiveness of germination and iron fortification on iron concentration and bioavailability of brown rice. Iron fortification during germination process with 0.05-2 g/L ferrous sulfate increased the iron concentration in germinated brown rice from 1.1 to 15.6 times than those in raw brown rice. Based on the recommended dietary allowance of iron, maximum germination rate and γ-aminobutyric acid, we recommend the brown rice fortified with 0.25 g/L FeSO(4) as a suitable fortification level to use in germination process. Iron fortification during the germination process has a positive effect on iron concentration and bioavailability. A significant difference was observed among the cultivars in respect to the capacity for iron accumulation and bioavailability. Germination alone could improve in vitro iron solubility, but had no effect on iron bioavailability in Caco-2 cell, the additional fortification process should be combined to get high amount of bioavailable iron from the brown rice. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. INTERPRETATION OF AT-LINE SPECTRA FROM AFS-2 BATCH #3 FERROUS SULFAMATE TREATMENT

    Energy Technology Data Exchange (ETDEWEB)

    Kyser, E.; O' Rourke, P.

    2013-12-10

    Spectra from the “at-line” spectrometer were obtained during the ferrous sulfamate (FS) valence adjustment step of AFS-2 Batch #3 on 9/18/2013. These spectra were analyzed by mathematical principal component regression (PCR) techniques to evaluate the effectiveness of this treatment. Despite the complications from Pu(IV), we conclude that all Pu(VI) was consumed during the FS treatment, and that by the end of the treatment, about 85% was as Pu(IV) and about 15% was as Pu(III). Due to the concerns about the “odd” shape of the Pu(IV) peak and the possibility of this behavior being observed in the future, a follow-up sample was sent to SRNL to investigate this further. Analysis of this sample confirmed the previous results and concluded that it “odd” shape was due to an intermediate acid concentration. Since the spectral evidence shows complete reduction of Pu(VI) we conclude that it is appropriate to proceed with processing of this the batch of feed solution for HB-Line including the complexation of the fluoride with aluminum nitrate.

  3. Report on assessment of the mechanism of bacterially assisted oxidation of pyritic uranium tailings

    International Nuclear Information System (INIS)

    Halbert, B.B.; Scharer, J.M.; Knapp, R.A.

    1984-07-01

    The oxidation of pyritic minerals has been shown to be catalyzed by the presence of iron- and sulphur-oxidizing bacteria. Thiobacillus ferroxidans plays the most significant role in the formation and propagation of acidic conditions. Optimum growth conditions for the T. ferroxidans occurs at a temperature of 35 degrees C and pH of 2 to 3. Bacterially assisted oxidation of pyrite involves both direct and indirect contact mechanisms. The direct contact mechanism entails enzymatic oxidation of the insoluble sulphide moiety. The indirect mechanism involves bacterial oxidation of the dissolved ferrous component to the ferric state. The ferric iron, in turn, acts as the prime oxidant of pyrite and is reduced to ferrous iron. The re-oxidation of the dissolved ferrous component which is catalyzed by bacterial activity, completes the cyclic process. The rate of bacterial oxidation is affected by: the geochemistry and reactivity of the pyritic material; the amount of pyrite present in the waste material and the exposed surface area of the pyritic component; the availability of oxygen and carbon dioxide; the pH and temperature of the leach solution; and the presence (or absence) of organic inhibitors. Of the above factors, oxygen has been frequently identified as the rate limiting reactant in tailings

  4. An experimental determination of ferrous chloride and acetate complexation in aqueous solutions to 300°C

    Science.gov (United States)

    Palmer, Donald A.; Hyde, K. E.

    1993-04-01

    The formation of the monochloroiron(II) complex, FeCl +, was studied potentiometrically from 125 to 295°C at 25 degree intervals at one molal ionic strength in aqueous solutions containing acetic acid, sodium acetate, and sodium trifluoromethanesulfonate. In this method, competition between chloride and acetate ions for the ferrous cation resulted in a change in solution pH, which in turn was monitored in situ in a hydrogen-electrode, concentration cell. A simple empirical approach was used to extrapolate these formation quotients to infinite dilution. The resulting constants proved to be in excellent agreement with previous spectrophotometric results obtained from 25 to 200°C. Thus, the present study confirms the validity of the conclusions made based on these earlier data concerning the solubility of Fe-containing minerals in hydrothermal brines. Formation constants at infinite dilution for FeCl + are compared with the stability of ferrous acetate and hydroxide complexes. The original potentiometric titration data for ferrous acetate complex formation were combined in a new fit with values determined from the present study at unit ionic strength. Two empirical treatments (namely the isocoulombic method and the temperature/water density function) were considered for fitting and extrapolating the infinite dilution formation constants to 350°C.

  5. Development of structural diagram of automated dispatch control system for power consumption at non-ferrous metallurgy enterprises

    Science.gov (United States)

    Klyuev, R. V.; Bosikov, I. I.; Madaeva, M. Z.; A-V Turluev, R.

    2018-03-01

    The structural scheme of the automated control system of power consumption at the industrial enterprise is developed in the article. At the non-ferrous metallurgy enterprise, an energy inspection and a rank analysis of the electrical energy consumption of the main processing equipment were carried out. It is established that the enterprises of non-ferrous metallurgy are a complex process system consisting of a set of thousands of jointly functioning technological facilities. For the most effective estimation of power consumption of enterprises, it is reasonable to use the automated system of dispatching control of power consumption (ASDCPC). The paper presents the results of the development of the ASDCPC structural diagram that allows one to perform on-line control and management of the energy and process parameters of the main production units and the enterprise as a whole. As a result of the introduction of ASDCPC at the non-ferrous metallurgy enterprise, the consumed active power was reduced during the peak hours of the load by 20%, the specific electricity consumption - by 14%, the cost of the energy component in the cost of production of hard alloys - by 3%.

  6. Ferrous Ion Chelating, Superoxide Anion Radical Scavenging and Tyrosinase Inhibitory Properties of Pure and Commercial Essential Oils of Anetrhum Graveolens

    Directory of Open Access Journals (Sweden)

    Sh Darvish Alipour Astaneh

    2013-04-01

    Full Text Available Introduction: Despite slight toxicities of essential oils, they are not under strict control in many countries. Anethum graveolens is widely consumed and its essential oils are at public reach. This study was designed to study essential oils of Anethum graveolens. Methods: The biological properties of pure and commercial essential oils of Anethum graveolens were investigated. In fact, Ferrous ion chelating activity, superoxide anion radical scavenging property, tyrosinase inhibition and total flavonoids of the oils were determined. Results: Chelating activity of 7.8 µg of EDTA was equivalent to 2 µg of the pure oil. The oils had superoxide anion radical scavenging activities which may be related to their total phenol and flavonoid contents. IC50 of ferrous ion chelating, antityrosiase and superoxide anion radical scavenging activities of pure and commercial oils were 1.3, 1.4, 1 and (171.6, 589, 132 µg respectively. Antityrosiase activity of 6.4 µg pure oil was equal to 1000 µg of the commercial oil. Conclusion: Anethum possesses antioxidative and free radical scavenging properties. This oil chelates ferrous ions and superoxide radicals. It is effective in formation of reactive toxic products. Anethum has good potentials regarding its applications in food and drug industries.

  7. The ferrous iron transporter FtrABCD is required for the virulence of Brucella abortus 2308 in mice.

    Science.gov (United States)

    Elhassanny, Ahmed E M; Anderson, Eric S; Menscher, Evan A; Roop, R Martin

    2013-06-01

    Iron transport has been linked to the virulence of Brucella strains in both natural and experimental hosts. The genes designated BAB2_0837-0840 in the Brucella abortus 2308 genome sequence are predicted to encode a CupII-type ferrous iron transporter homologous to the FtrABCD transporter recently described in Bordetella. To study the role of the Brucella FtrABCD in iron transport, an isogenic ftrA mutant was constructed from B. abortus 2308. Compared with the parental strain, the B. abortus ftrA mutant displays a decreased capacity to use non-haem iron sources in vitro, a growth defect in a low iron medium that is enhanced at pH 6, and studies employing radiolabelled FeCl3 confirmed that FtrABCD transports ferrous iron. Transcription of the ftrA gene is induced in B. abortus 2308 in response to iron deprivation and exposure to acid pH, and similar to other Brucella iron acquisition genes that have been examined the iron-responsiveness of ftrA is dependent upon the iron response regulator Irr. The B. abortus ftrA mutant exhibits significant attenuation in both cultured murine macrophages and experimentally infected mice, supporting the proposition that ferrous iron is a critical iron source for these bacteria in the mammalian host. © 2013 John Wiley & Sons Ltd.

  8. A comparative study of iron bioavailability from cocoa supplemented with ferric pyrophosphate or ferrous fumarate in rats.

    Science.gov (United States)

    Navas-Carretero, S; Sarriá, B; Pérez-Granados, A M; Schoppen, S; Izquierdo-Pulido, M; Vaquero, M P

    2007-01-01

    Food iron fortification can be a good strategy to prevent iron deficiency. Iron bioavailability from cocoa powder enriched with ferric pyrophosphate encapsulated in liposomes or ferrous fumarate was assessed in rats. Three groups of rats consumed during 28 days either a control diet or two diets prepared with ferric pyrophosphate- or ferrous fumarate-enriched cocoa powder as the unique source of iron. Body weight and food intake were monitored and last-week feces were collected. On day 28, animals were sacrificed and livers and spleens were removed. Hemoglobin and total iron binding capacity (TIBC) were determined. There were no significant differences in body weight and food intake. Apparent iron absorption and % absorption/intake were significantly lower in rats consuming enriched cocoa compared to the control group, without significant differences due to the iron form. Enriched cocoa groups showed significantly lower spleen iron content and concentration than the control. Liver iron was lower in the ferric pyrophosphate group compared to the other two groups. Hemoglobin and TIBC values showed a deficient iron status in ferric pyrophosphate rats. Cocoa powder is a good vehicle for iron fortification when enriched with ferrous fumarate compared to ferric pyrophosphate encapsulated in liposomes. Copyright 2007 S. Karger AG, Basel.

  9. Bioavailability of stabilised ferrous gluconate with glycine in fresh cheese matrix: a novel iron compound for food fortification.

    Science.gov (United States)

    Pizarro, Fernando; Boccio, José; Salgueiro, María; Olivares, Manuel; Carmuega, Esteban; Weill, Ricardo; Marque, Sebastien; Frereux, Marine; Noirt, Florence

    2013-03-01

    Iron fortification of foods continues to be one of the preferred ways of improving the iron status of the population. Dairy product is a common product in the diet; therefore, it is a plausible vehicle for iron fortification. This study aims to investigate the bioavailability of ferrous gluconate stabilised with glycine (FGSG) in a fresh cheese fortified with zinc. The iron bioavailability of fresh cheese fortified with either FGSG and with or without zinc and FGSG in aqueous solution and a water solution of ferrous ascorbate (reference dose) was studied using double radio iron ((55)Fe and (59)Fe) erythrocyte incorporation in 15 male subjects. All subjects presented with normal values for iron status parameters. The geometric mean of iron bioavailability for the water solution of FGSG was 38.2 %, adjusted to 40 % from reference doses (N.S.). Iron bioavailability in fresh cheese fortified with Ca and Zn was 15.4 % and was 23.1 % without Zn, adjusted to 40 % from reference doses (N.S.). The results of the present study show that the novel iron compound ferrous gluconate stabilised with glycine in a fresh cheese matrix is a good source of iron and can be used in iron fortification programmes.

  10. Contribution of nuclear analysis methods to the certification of BCR reference materials for non-metals in non-ferrous metals

    International Nuclear Information System (INIS)

    Pauwels, J.

    1979-01-01

    A number of reference materials for oxygen in different non-ferrous metals have been certified by BCR in the frame of a multidisciplinary Community project. The contribution of nuclear analysis methods is illustrated by several examples concerning the optimization of sample preparation techniques, the analysis of low and high oxygen non-ferrous metals and the extension of the program to other non-metals, especially nitrogen and carbon. (author)

  11. Efficacy, Tolerability, and Acceptability of Iron Hydroxide Polymaltose Complex versus Ferrous Sulfate: A Randomized Trial in Pediatric Patients with Iron Deficiency Anemia

    Directory of Open Access Journals (Sweden)

    Beril Yasa

    2011-01-01

    Full Text Available Iron polymaltose complex (IPC offers similar efficacy with superior tolerability to ferrous sulfate in adults, but randomized trials in children are rare. In a prospective, open-label, 4-month study, 103 children aged >6 months with iron deficiency anemia (IDA were randomized to IPC once daily or ferrous sulfate twice daily, (both 5 mg iron/kg/day. Mean increases in Hb to months 1 and 4 with IPC were 1.2±0.9 g/dL and 2.3±1.3 g/dL, respectively, (both P=0.001 versus baseline and 1.8±1.7 g/dL and 3.0±2.3 g/dL with ferrous sulfate (both P=0.001 versus baseline (n.s. between groups. Gastrointestinal adverse events occurred in 26.9% and 50.9% of IPC and ferrous sulfate patients, respectively (P=0.012. Mean acceptability score at month 4 was superior with IPC versus ferrous sulfate (1.63±0.56 versus 2.14±0.75, P=0.001. Efficacy was comparable with IPC and ferrous sulfate over a four-month period in children with IDA, but IPC was associated with fewer gastrointestinal adverse events and better treatment acceptability.

  12. Cooperative functions of manganese and thiol redox system against oxidative stress in human spermatozoa

    Directory of Open Access Journals (Sweden)

    Amrit Kaur Bansal

    2009-01-01

    Full Text Available Aims: In this study, the effects of 0.1 mM Mn 2+ on thiol components (total thiols [TSH], glutathione reduced [GSH], glutathione oxidized [GSSG] and redox ratio [GSH/ GSSG] have been determined in human spermatozoa. Settings and Design: The subjects of the study were healthy males having more than 75% motility and 80 x 10 6 sperms/mL. Materials and Methods: Fresh semen was suspended in phosphate-buffered saline (PBS (pH 7.2 and this suspension was divided into eight equal fractions. All fractions, control (containing PBS and experimental (treated/untreated with [ferrous ascorbate, FeAA - 200 FeSO 4 μM, 1000 μM ascorbic acid, nicotine (0.5 mM and FeAA + nicotine], supplemented/unsupplemented with Mn 2+ [0.1 mM], were incubated for 2 h at 378C. These fractions were assessed for determining the thiol components. Statistical Analysis: The data were statistically analyzed by Students " t" test. Results and Conclusions: Ferrous ascorbate, nicotine and ferrous ascorbate + nicotine induced oxidative stress and decreased GSH and redox ratio (GSH/GSSG ratio but increased the TSH and GSSG levels. Mn 2+ supplementation improved TSH, GSH and redox ratio (GSH/GSSG but decreased the GSSG level under normal and oxidative stress conditions. Thiol groups serve as defense mechanisms of sperm cells to fight against oxidative stress induced by stress inducers such as ferrous ascorbate, nicotine and their combination (ferrous ascorbate + nicotine. In addition, Mn 2+ supplementation maintains the thiol level by reducing oxidative stress.

  13. STUDY OF THE IMPACT OF PHOSPHOGYPSUM ADDITIVE AND FERROUS SULPHATE SOLUTION ON THE MECHANISM OF THE MAGNESIA-BISHOFIT COMPOSITION

    Directory of Open Access Journals (Sweden)

    DEREVIANKO V. N.

    2015-11-01

    Full Text Available Problem statement. Phosphogypsum is a very pure raw material [16] with a negative, from a technical point of view, elongated shape of calcium dihydrate crystals (due to the formation conditions, which remains the same after both dehydration in dry air and grinding, this makes technical difficulties relating to further processing of the product into a binder, consequently, water resistance and plasticity of magnesium solutions can be improved by adding primary and secondary phosphates without strength reduction. Famous experts on phosphogypsum Yu. P. Meshcheryakov and N. A. Kolev [8] found, that when adding phosphogypsum instead of natural gypsum during grinding of Portland cement, which is intended to control the setting time of the mixture, there occurred reduction in the initial setting time from 1 h 55 min up to 1 h 36 min (when adding 4 % agent, and the final setting time was decreased from 6 h 15 min up to 6 min. After grinding of phosphogypsum, there appeared a fresh surface, on which the electron emission phenomenon occurs, however, not the entire surface emits, but only the active centres, where field strength reaches 108 V/cm. The positively charged active centres have low CaSO4 2H2O concentration on their surface. Purpose. Specifying the optimal amount of phosphogypsum and ferrous sulphate solution added, studying their impact on the curing mechanism of the magnesia-bishofit composition. Conclusion. To increase the sulphate compound, required for the crystallinity [10] reduction and magnesia stone sealing [4], the ferrous sulphate solution have been added to the composition formulation, ferrous sulphate anions immediately polarize free calcium ions with the formation of CaSO4∙2H2O. P. P. Budkov's experiments [8] prove that the larger the magnesia cement-to-sulphate stone ratio, the lower the setting time of the composition, and the higher the tensile strength of the stone. Moreover, V. V. Shchelyaghin [15] recommended adding ferrous

  14. Reduction of Mn-oxides by ferrous iron in a flow system: column experiment and reactive transport modeling

    DEFF Research Database (Denmark)

    Postma, Diederik Jan; Appelo, C. A. J.

    2000-01-01

    (OH)3, Mn21 and H1. The protons are transported downstream and cause the disproportionation of MnOOH at a separate reaction front. Between the two Mn reaction fronts, the dissolution and precipitation of Fe(OH)3 and Al(OH)3 act as proton buffers. Reactive transport modeling, using the code PHREEQC 2...

  15. A comparison between experimental results and a mathematical model of the oxidation reactions induced by radiation of ferrous ions

    International Nuclear Information System (INIS)

    Sanchez-Mejorada, G.; Frias, D.; Negron-Mendoza, A.; Ramos-Bernal, S.

    2008-01-01

    The dependence of the response of chemical dosimeters as a function of the irradiation temperature is an important issue that has not yet been addressed within a mathematical modeling framework. The temperature dependence of the dose-response function has to be taken into account in practical applications, mainly in frozen food sterilization by radiation. Significant errors may occur if the dependence of the dosimeter response on the irradiation temperature is not taken into account properly. The experimental results obtained irradiating iron salt solutions at different temperatures below and above 0 deg. C show that the change in the valence of Fe 2+ as a function of dose are linear for both liquid and frozen solutions. This led us to conclude that the iron salt solution seems suitable for low-temperature applications having a linear dose-response up to 600 Gy, despite a progressive decrease of sensitivity as temperature decreases. A nonlinear differential model for the kinetics of reactions induced by radiation in iron salt solutions was established. In the model a temperature correction factor was included in order to take into account abrupt changes observed in the kinetics of the chemical process when the irradiated solution's allotropic phase changes from liquid to solid (ice). Fitting the kinetic model to the experimental results at different temperatures we found the temperature correction factors

  16. Reduction of Mn-oxides by ferrous iron in a flow system: column experiment and reactive transport modeling

    DEFF Research Database (Denmark)

    Postma, Diederik Jan; Appelo, C. A. J.

    2000-01-01

    of Mn21, Al31, Fe31, and Fe21 in the column outlet solution. However, the initial breakthrough of a peak of Ca21 and the observed pH buffering indicated that exchange processes were of importance as well. The amount of potential exchangers, such as birnessite and ferrihydrite, did vary in the course......(OH)3, Mn21 and H1. The protons are transported downstream and cause the disproportionation of MnOOH at a separate reaction front. Between the two Mn reaction fronts, the dissolution and precipitation of Fe(OH)3 and Al(OH)3 act as proton buffers. Reactive transport modeling, using the code PHREEQC 2...... profiles are more gradual than indicated by the equilibrium model. Reaction kinetics for the dissolution of MnO2 and MnOOH and dissolution of Al(OH)3 were incorporated in the model, which explained the shape of the breakthrough curves satisfactorily. The results of this study emphasize the importance...

  17. Oxidative degradation of acid doped polybenzimidazole membranes and fuel cell durability in the presence of ferrous ions

    DEFF Research Database (Denmark)

    Liao, Jianhui; Yang, Jingshuai; Li, Qingfeng

    2013-01-01

    Phosphoric acid doped polybenzimidazole membranes have been explored as proton exchange membranes for high temperature polymer electrolyte membrane fuel cells. Long-term durability of the membrane is of critical concern and has been evaluated by accelerated degradation tests under Fenton conditio...

  18. Ferrous sulphate mono and heptahydrate reduction of hexavalent chromium in cement: effectiveness and storability

    Directory of Open Access Journals (Sweden)

    Valverde, J. L.

    2005-09-01

    Full Text Available In Community legislation, substances containing hexavalent chromium are classified as carcinogenic, mutagenic and sensitizing. In cement, hexavalent chromium intensifies sensitization and may set off severe allergic reactions in workers in routine contact with the product, whether in the factory or on construction sites. The allergic or contact dermatitis causes is a very painful disease that may lead to permanent worker disability. According to Directive 2003/53/EC of the European Parliament and the Council, Governments of all member countries will be required to prohibit the marketing and use, as of 17 January 2005, of any cement or cement preparation containing more than 2 ppm of chromium (VI. Hexavalent chromium can be reduced with ferrous sulphate to trivalent chromium, which is water-insoluble and therefore innocuous to the skin. The present paper reports the effects of adding ferrous sulphate mono- or heptahydrate to a commercial cement and the storage time of the mix on the concentration of hexavalent chromium. The salts studied were found to effectively reduce hexavalent chromium in cement for at least three months.

    Las sustancias que contienen cromo hexavalente están clasificadas en la legislación comunitaria como sustancias carcinogénicas, mutagénicas y sensibilizantes. El cromo hexavalente del cemento potencia la sensibilización y provoca graves reacciones alérgicas que sufren bastante a menudo los trabajadores que lo manipulan habitualmente, ya sea en fábrica o en el sector de la construcción. La dermatitis alérgica o de contacto que produce es muy dolorosa y puede dejar a los trabajadores en estado de discapacidad. La Directiva 2003/53/CE del Parlamento Europeo y del Consejo, exige a los Gobiernos de los países miembros, que a partir del 17 de enero de 2005, prohiban el uso y la comercialización de todos aquellos cementos y preparados que contengan cemento, cuyo contenido en cromo (VI soluble, una vez hidratados

  19. Analysis of Chemical Composition of Non-Ferrous Metal Items from the Ananyino Burial Ground

    Directory of Open Access Journals (Sweden)

    Saprykina Irina А.

    2016-03-01

    Full Text Available The article presents results of an analysis conducted by the authors in order to study chemical composition of items from non-ferrous metals found on the Ananyino burial ground. A number of research methods, including OES, XRF and TXRF was applied to study a selection of 387 samples of arrow- and spearheads, celts, tail-pieces, warhammers, poleaxes, knives and daggers, as well as items of attire and jewelry, some sporadic details of harness and bridle. The fi ndings are quite comparable. The results were classifi ed by the geochemical principle of 1,0% alloyage threshold. It was found out that the sample primarily consists of copper items, including “pure” copper and copper with a wide range of trace elements (particularly, Ni, As, Sb. The core (48% consists of copper items with traces of antimony and arsenic, or “pure” copper (7%, tin or triple bronze (40%; it also includes some other types of alloys based on copper or silver (5%. As the analysis has shown, complex ores seem to be the most probable source of copper. Traditionally, the Urals, the Sayan and the Altay Mountains, Kazakhstan and the Northern Caucasus were regarded as the most probable minefi elds to supply ores to the barren regions of Eastern Europe. While ore sources for products made of metallurgical “pure” copper are localized within the Ural mining and metallurgical region, metal sources for items cast from different groups of alloys (rather than imports of ready-made products require further research.

  20. Indoor atmospheric corrosion of historical ferrous alloys. System characterisation, mechanisms and modelling discussion

    International Nuclear Information System (INIS)

    Monnier, J.

    2008-12-01

    Understanding the mechanisms of indoor atmospheric corrosion in iron alloys is of primary importance in several fields, including for the conservation of Middle Ages monuments or the long term storage of nuclear waste. In this research, a double approach was developed, combining fine characterisation of corrosion systems and design of experiments to answers specific questions related to mechanisms understanding. Iron indoor atmospheric corrosion was investigated on samples coming from the reinforcing chain of the Amiens cathedral (15. century). In the first stage, the corrosion system has been extensively characterised from the macroscopic to the nano-metric scale. In particular, structural micro-analysis (μ-Raman, μ-XRD, μ-XAS) has been used to locate, identify and quantify the oxidised phases. Rust layers are composed of a matrix of nano-metric goethite, with low quantities of lepidocrocite and akaganeite mostly located in the extern part of the corrosion system. In addition, clear marblings are dispersed in the matrix, which are sometimes connected with the metal core. Although these may contain maghemite, these marblings are generally made of ferri-hydrite/feroxyhite phases. In the second stage, specific experiments have been carried out in an unsaturated marked medium to locate oxygen reduction sites in the rust layers. Several cases were evidenced, depending on the rust layer morphology. In addition, reduction processes of model phases have been studied in situ, using an electrochemical cell coupled with structural characterisation techniques. This combination highlighted the influence of reduction mode and pH on the type of reduced phase formed. From the obtained results, several mechanisms are proposed to explain the long term indoor atmospheric corrosion of iron, including rust layers morphology and phases properties. The different hypotheses have been integrated in a proposed method to diagnosis ancient ferrous systems stability. These hypotheses also

  1. Regional Logistics of Procurement of the Ferrous Scrap by the Iron-and-Steel Companies of the Russian Federation

    Directory of Open Access Journals (Sweden)

    Tatiana Aleksandrovna Ivanova

    2017-03-01

    Full Text Available The article discusses the relevant problem of iron-and-steel companies saving on purchasing the scrap metal. The analysis of the current state of the ferrous scrap market in the Russian Federation, trends of its development, led the authors to an opportunity to reduce the cost for purchasing scrap trough the optimal distribution of the regions between Russian iron-and-steel companies where they purchase ferrous scrap. The optimization of the regional structure of the scrap procurement taking into account the regional volumes of its generation and consumption results from using the linear programming methods applying three variants of the problem statement: minimizing the total cost of the scrap delivery to the factory, minimizing the total cost of the scrap at the “export parity” price with delivery, minimizing the total cost of the scrap at the actual prices with delivery. The authors have developed software for performing the calculations. The source are the database of the JSC Russian Railways, which provides information about the transportation of the ferrous scrap between stations of the Russian Federation by railroad; railway rates guide between railway stations of the Russian Federation; statistical data on the prices for scrap metal of the type 3A in “export windows”; actual purchasing prices for the scrap of the 3A type for the range of separate companies of the Russian Federation for several years. As a result, the authors have obtained the optimal regional structure of scrap purchasing for customers in the Russian Federation. We have formulated the recommendations for individual companies regarding the optimal routes of the procurement with scrap. The study has confirmed the possibility to decrease expanses for purchasing the scrap metal for all iron-and-steel factories of the Russian Federation through the optimization of the regional structure of procurement. It is also has allowed to estimate the possibility to cut expenses

  2. Alginate inhibits iron absorption from ferrous gluconate in a randomized controlled trial and reduces iron uptake into Caco-2 cells.

    Science.gov (United States)

    Wawer, Anna A; Harvey, Linda J; Dainty, Jack R; Perez-Moral, Natalia; Sharp, Paul; Fairweather-Tait, Susan J

    2014-01-01

    Previous in vitro results indicated that alginate beads might be a useful vehicle for food iron fortification. A human study was undertaken to test the hypothesis that alginate enhances iron absorption. A randomised, single blinded, cross-over trial was carried out in which iron absorption was measured from serum iron appearance after a test meal. Overnight-fasted volunteers (n = 15) were given a test meal of 200 g cola-flavoured jelly plus 21 mg iron as ferrous gluconate, either in alginate beads mixed into the jelly or in a capsule. Iron absorption was lower from the alginate beads than from ferrous gluconate (8.5% and 12.6% respectively, p = 0.003). Sub-group B (n = 9) consumed the test meals together with 600 mg calcium to determine whether alginate modified the inhibitory effect of calcium. Calcium reduced iron absorption from ferrous gluconate by 51%, from 11.5% to 5.6% (p = 0.014), and from alginate beads by 37%, from 8.3% to 5.2% (p = 0.009). In vitro studies using Caco-2 cells were designed to explore the reasons for the difference between the previous in vitro findings and the human study; confirmed the inhibitory effect of alginate. Beads similar to those used in the human study were subjected to simulated gastrointestinal digestion, with and without cola jelly, and the digestate applied to Caco-2 cells. Both alginate and cola jelly significantly reduced iron uptake into the cells, by 34% (p = 0.009) and 35% (p = 0.003) respectively. The combination of cola jelly and calcium produced a very low ferritin response, 16.5% (p iron for the purpose of food fortification. ClinicalTrials.gov NCT01528644.

  3. Ferrous and ferric state of cytochromes P450 in intact Escherichia coli cells: a possible role of cytochrome P450-flavodoxin interactions.

    Science.gov (United States)

    Culka, Martin; Milichovsky, Jan; Jerabek, Petr; Stiborova, Marie; Martinek, Vaclav

    2015-01-01

    Cytochromes P450 (CYPs) are heme enzymes oxygenating a broad range of substrates. Their activity is dependent on the presence of a suitable electron donor (eukaryotic NADPH:CYP oxidoreductase or cytochrome b5). The Escherichia naturally contain no CYPs and no NADPH:CYP oxidoreductase, however it was reported that some CYPs heterologously expressed in E. coli may exist in the ferrous form. A small bacterial flavoprotein, flavodoxin is considered to be responsible for reduction some of these CYPs. The reduction state of several human CYPs expressed in the intact living E. coli cells was examined. In addition, molecular dynamics and steered molecular dynamics simulations were performed to predict and compare affinity of flavodoxin toward selected CYPs. We determined the reduction state of five human CYPs heterologously expressed in E. coli. The computationally predicted stabilities of CYP-flavodoxin complexes correlate with the percentage of reduced CYPs in bacterial cells. The mean electron transfer distance within optimized complexes was also related to the percentage of reduced CYPs. Depending on the resting state, the CYPs heterologously expressed in E. coli could be divided into two groups; CYP2C8, 2C9, 3A4 are in E. coli present mainly in the oxidized form; while CYP1A1, 1A2, 2A6, 2A13, 2B6, 2D6 are found predominantly in the reduced form. We found a significant correlation between the stability of CYP-flavodoxin complexes and the percentage of reduced CYPs in bacteria. Hence, the naturally expressed flavodoxin is probably responsible for reduction of a larger group of human CYPs in bacterial cells.

  4. Estimation of snow pollution in the region of non-ferrous metallurgy enterprises by the neutron activation method

    International Nuclear Information System (INIS)

    Khatamov, Sh.; Khamidova, R.; Kist, A.A.

    1980-01-01

    Possibility of determination of more than 25 chemical elements in snow water selected in the region of non-ferrous metallurgy enterprises has been shown using the methods of neutron activation and γ-spectrometry of high resolution. Elements were determined from one sample by three-fold irradiation in the nuclear reactor depending on the half-life period and other nuclear activation parameters of the formed radioisotopes. The analysis of snow cover has revealed the character of pollution of surrounding medium and air basin by toxical elements

  5. Lactoferrin or ferrous salts for iron deficiency anemia in pregnancy: A meta-analysis of randomized trials.

    Science.gov (United States)

    Abu Hashim, Hatem; Foda, Osama; Ghayaty, Essam

    2017-12-01

    This systematic review and meta-analysis aimed to evaluate the efficacy of daily oral bovine lactoferrin versus daily oral ferrous iron preparations for treatment of iron deficiency anemia (IDA) during pregnancy. Searches were conducted on PubMed, ScienceDirect, ClinicalTrials.gov and CENTRAL databases from inception to February 2017 and the bibliographies of retrieved articles were screened. The PRISMA Statement was followed. Published English language randomized trials comparing lactoferrin with oral ferrous iron preparations in pregnant women with iron deficiency anemia were included. Quasi-randomized, non- randomized or studies including other known cause of anemia, gestational or pre-existent maternal diseases were excluded. Accordingly, 4 eligible trials (600 women) were analyzed. Primary outcome was change in hemoglobin level at 4 weeks of treatment. Secondary outcomes were; change in serum ferritin and iron, rates of gastrointestinal side effects, preterm birth, low birthweight, neonatal death and mean birthweight. Quality assessment was performed by the Cochrane risk of bias tool. Odds ratio and mean difference were used to integrate dichotomous and continuous outcomes respectively. Pooled estimates for change in hemoglobin levels at four weeks favored daily oral lactoferrin over daily oral ferrous sulphate (mean difference 0.77; 95% confidence interval [CI] 0.04-1.55; P=0.04, 4 trials, 600 women). However, after subgroup analysis (degree of anemia), no significant difference in hemoglobin levels were found between both groups in mild anemia (mean difference 0.80; 95% CI -0.21 to 1.82, 3 trials, 372 women), but a significant increase favoring lactoferrin was reported in moderate anemia (mean difference 0.68; 95% CI 0.53-0.83; P<0.00001, one trial, 228 women). Significantly less gastrointestinal side effects were reported with lactoferrin treatment. No significant differences existed with regard to other outcomes. In conclusion, for pregnant women with IDA

  6. Irradiation of ferrous ammonium sulfate for its use as high absorbed dose and low-temperature dosimeter

    International Nuclear Information System (INIS)

    Juarez-Calderon, J.M.; Negron-Mendoza, A.; Ramos-Bernal, S.

    2007-01-01

    In the present paper, we study the response of crystalline ammonium ferrous sulfate as a function of the irradiation dose and temperature. The dose studied ranged from 33.5 to 546 kGy. The temperature regimen varied from 77 K (liquid nitrogen) to 311 K. The analysis of the samples was made by UV spectroscopy and EPR. The results show that the change in absorbance of the dosimeter was linear with respect to the absorbed dose in the range studied. There is a small influence of the irradiation temperature in the response of the iron salt. The dose rate and storage time after irradiation was of no importance in this application

  7. Fine and ultrafine emission dynamics from a ferrous foundry cupola furnace.

    Science.gov (United States)

    Meléndez, Antton; García, Estibaliz; Carnicer, Pedro; Pena, Egoitz; Larrión, Miren; Legarreta, Juan Andres; Gutiérrez-Cañas, Cristina

    2010-05-01

    Aerosol size distributions from ferrous foundry cupola furnaces vary depending on semicontinuous process dynamics, time along the tap-to-tap cycle, dilution ratio, and the physical and chemical nature of the charge and fuel. All of these factors result in a highly time-dependent emission of particulate matter (PM) 2.5 pm or less in aerodynamic diameter (PM2.5)--even on a mass concentration basis. Control measures are frequently taken on the basis of low-reliability parameters such as emission factors and loosely established mass ratios of PM2.5 to PM 10 microm or less in aerodynamic diameter (PM1.0). The new environmental requirements could entail unexpected and undesired drawbacks and uncertainties in the meaning and effectiveness of process improvement measures. The development of process-integrated and flue-gas cleaning measures for reduction of particle emissions requires a better knowledge of generation mechanisms during melting. Available aerosol analyzers expand the range of control issues to be tackled and contribute to greatly reduce the uncertainty of engineering decisions on trace pollutant control. This approach combines real-time size distribution monitoring and cascade impactors as preseparators for chemical or morphological analysis. The results allow for establishing a design rationale and performance requirement for control devices. A number size distribution below 10 microm in aerodynamic equivalent diameter was chosen as the main indicator of charge influence and filter performance. Size distribution is trimodal, with a coarse mode more than 12 microm that contributes up to 30% of the total mass. A temporal series for these data leads to identification of the most relevant size ranges for a specific furnace (e.g., the most penetrating size range). In this cupola, this size range is between 0.32 and 0.77 microm of aerodynamic equivalent diameter and defines the pollution control strategy for metals concentrating within this size range. Scrap

  8. Unsteady Casson nanofluid flow over a rotating cone in a rotating frame filled with ferrous nanoparticles: A numerical study

    Energy Technology Data Exchange (ETDEWEB)

    Raju, C.S.K., E-mail: sivaphd90@gmail.com; Sandeep, N., E-mail: dr.nsrh@gmail.com

    2017-01-01

    In this study, we investigated the momentum and heat transfer characteristics of Casson nanofluid flow over a rotating cone in a rotating frame filled with water based CoFe{sub 2}O{sub 4} nano particles. Heat flux conditions and wall temperature conditions are very important in controlling of up and down heat transport phenomena's in industrial as well as engineering application. Resulting set of coupled nonlinear governing equations are solved numerically using Runge–Kutta based shooting technique. In graphical results we presented dual solutions for the prescribed wall temperature (PWT) and prescribed heat flux (PHF) cases. The effect of governing parameters on velocity and temperature fields along with the skin friction coefficient and the heat transfer rate are presented with the help of graphs and tables. Results indicate that the rising values of the volume fraction of ferro particles and buoyancy parameter have tendency to improve the skin friction coefficient as well as the heat transfer rate for both the prescribed wall temperature (PWT) and prescribed heat flux (PHF) cases. - Highlights: • Mathematical model for unsteady nanofluid flow over a rotating cone in a rotating frame. • Water based ferrous nanoparticles suspended Casson model is studied. • Non-uniform heat source/sink is incorporated in the model. • Dual nature found for PWT and PHF cases. • Ferrous nanoparticles effectively enhance the heat transfer rate.

  9. Isotopic characterisation of lead in contaminated soils from the vicinity of a non-ferrous metal smelter near Plovdiv, Bulgaria

    Energy Technology Data Exchange (ETDEWEB)

    Bacon, Jeffrey R. [Macaulay Institute, Craigiebuckler, Aberdeen AB15 8QH (United Kingdom)]. E-mail: j.bacon@macaulay.ac.uk; Dinev, Nikolai S. [N Poushkarov Institute of Soil Science and Agroecology, Sofia (Bulgaria)

    2005-03-01

    Soil samples from the vicinity of a non-ferrous metal smelter near Plovdiv, Bulgaria contained very high concentrations of cadmium, lead and zinc (up to 140, 4900 and 5900 mg kg{sup -1}, respectively). A roadside soil in a relatively uncontaminated area also contained high concentrations of the same metals (24, 1550 and 1870 mg kg{sup -1}, respectively) indicating that the transport of ores could be a source of contamination. Even though the lead isotope ratios in all the samples fell within a very narrow range (for example, 1.186-1.195 for {sup 206}Pb/{sup 207}Pb), the samples could be differentiated into three distinct groups: ores ({sup 206}Pb/{sup 207}Pb and {sup 208}Pb/{sup 207}Pb ratios of 1.1874-1.1884 and 2.4755-2.4807, respectively), current deposition (1.1864 and 2.4704-2.4711, respectively) and local background (1.1927-1.1951 and 2.4772-2.4809, respectively). Although most of the current deposition has its origin in the ores used at the smelter, up to 12% could be from other sources such as petrol lead. - Although soils in the vicinity of a non-ferrous metal smelter near Plovdiv, Bulgaria, have become highly contaminated with the ores used, lead isotope analysis has revealed that up to 12% of current deposition could be from other sources such as petrol lead.

  10. Iron corrosion in archaeological context: Structural refinement of the ferrous hydroxychloride β-Fe2(OH)3Cl

    International Nuclear Information System (INIS)

    Réguer, Solenn; Mirambet, Francois; Rémazeilles, Céline; Vantelon, Delphine; Kergourlay, Florian; Neff, Delphine; Dillmann, Philippe

    2015-01-01

    Highlights: • Precise determination of the structure of β-Fe 2 (OH) 3 Cl on archaeological marine artefact. • Novel XAS results, including fitting procedures of natural β-Fe 2 (OH) 3 Cl. • Novel XRD refinement of β-Fe 2 (OH) 3 Cl from archaeological context. • One of the rare demonstration of the DiffAbs beamline efficient original set up. - Abstract: Ferrous hydroxysalts are found in corrosion layers of archaeological ferrous objects extracted from oxygen-poor environments. The structure of synthetic and natural β-Fe 2 (OH) 3 Cl was investigated by X-ray absorption spectroscopy and X-ray diffraction. The local environments of Cl − and Fe 2+ were precisely determined showing the same structure around Cl − and Fe 2+ atoms whatever the natural or synthesized phase. The crystalline structure was refined confirming the rhombohedral unit cell and R-3m space group. However slight differences observed for the structural parameters and on XRD patterns suggested different crystallite size, strain effects and the influence of the crystallization process.

  11. Pathways of ferrous iron mineral formation upon sulfidation of lepidocrocite surfaces

    NARCIS (Netherlands)

    Hellige, K.; Pollok, K.; Larese-Casanova, P.; Behrends, T.; Peiffer, S.

    2012-01-01

    The interaction between S(-II) and ferric oxides exerts a major control for the sulphur and iron cycle and in particular for the carbon and electron flow in many aquatic systems. It is regarded to be a key reaction leading ultimately to pyrite formation, the pathways still remaining unresolved. We

  12. The Oxidation of Fe(II) in Acidic Sulfate Solutions with Air at Elevated Pressures : Part 2. Influence of H2SO4 and Fe(III)

    NARCIS (Netherlands)

    Wermink, Wouter N.; Versteeg, Geert F.

    2017-01-01

    The oxidation of ferrous ions in acidic sulfate solutions at elevated air pressures was investigated. The effect of the Fe2+ concentration, Fe3+ concentration H2SO4 concentration, and partial oxygen pressure on the reaction rate were determined at three different temperatures, that is, T = 90, 70,

  13. The Oxidation of Fe(II) in Acidic Sulfate Solutions with Air at Elevated Pressures : Part 1. Kinetics above 1 M H2SO4

    NARCIS (Netherlands)

    Wermink, Wouter N.; Versteeg, Geert F.

    2017-01-01

    The oxidation of ferrous ions in acidic sulfate solutions at elevated air pressures was investigated. The effect of the Fe2+ concentration, initial H2SO4 concentration and partial oxygen pressure on the reaction rate were determined at three different temperatures, that is, T = 90, 70, and 50

  14. Dual-emission of a fluorescent graphene oxide-quantum dot nanohybrid for sensitive and selective visual sensor applications based on ratiometric fluorescence.

    Science.gov (United States)

    Zhu, Houjuan; Zhang, Wen; Zhang, Kui; Wang, Suhua

    2012-08-10

    A novel nanohybrid ratiometric fluorescence probe comprised of fluorescent graphene oxide and quantum dots (QDs) has been prepared by bringing CdTe QDs of red fluorescence and fluorescent graphene oxide (FGO) of blue fluorescence together through electrostatic attraction and hydrogen bonding interaction between their surface functional groups including carboxyl and amine groups. The nanohybrid ratiometric fluorescence probe exhibits dual emissions at 450 and 650 nm under a single excitation wavelength and shows high sensitivity for the detection of ferrous ions in the presence of H₂O₂. Ferrous ions reacts with H₂O₂ to generate very reactive hydroxyl radicals which possess a strong oxidizing nature and easily capture the electrons from the surfaces of the CdTe QDs, leading to fluorescence quenching of the QDs and no effect on the fluorescence of the graphene oxide, which hence results in a great change of the fluorescence ratio. Moreover, the ratiometric fluorescence probe is not only extremely sensitive to ferrous ions, but is also selective over other biologically relevant metal cations. The changes of fluorescence colour ratios can be used for visual sensing applications for ferrous ions in the presence of hydrogen peroxide, and can also be used for the indication of the existence of hydrogen peroxide.

  15. Mechanical Behaviors of Friction Stir Spot Welded Joints of Dissimilar Ferrous Alloys under Opening-Dominant Combined Loads

    Directory of Open Access Journals (Sweden)

    Md. Abu Mowazzem Hossain

    2014-01-01

    Full Text Available Mechanical properties and failure behaviors of friction stir spot welded (FSSW joints of two dissimilar ferrous alloys, cold-rolled carbon steel (SPCC and 409L stainless steel (SUS 409L, are investigated under opening-dominant combined loads. The texture of dissimilar FSSW joints depends on the upper sheet material. The failure contours for the FSSW joints under combined loads are constructed in terms of the axial load and shear load by modifying existing failure criteria for resistance spot welds. The shape of the failure contour also depends on the upper sheet material. The failure contours are nearly elliptic in shape when the upper sheet is SPCC and are relatively straight lines when the upper sheet is SUS 409L.

  16. The dosimetry of 3 MeV and 14 MeV neutrons with the ferrous sulphate solution

    International Nuclear Information System (INIS)

    Pejuan, A.

    1980-03-01

    The aim of the present work is to determine the G value of a standard ferrous sulphate solution for neutrons with mean energies of 3 MeV and 14 MeV. The number of the transformed Fe ions is evaluated by means of a spectrophotometrical procedure and the absorbed energy is determined by applying the ionometrical method. Especial attention is payed to the calculation of the mean total dose in the irradiated sample taking radiation attenuation into account. For this purpose the spatial distribution of absorbed energy within the probe is determined. Further, it is investigated how the fraction of the γ component in the total absorbed dose varies in the sample, in order to evaluate its mean value, which is needed for the final determination of the G value for the neutron component. (orig.) [de

  17. Determination of dislocation density by electron backscatter diffraction and X-ray line profile analysis in ferrous lath martensite

    International Nuclear Information System (INIS)

    Berecz, Tibor; Jenei, Péter; Csóré, András; Lábár, János; Gubicza, Jenő

    2016-01-01

    The microstructure and the dislocation density in as-quenched ferrous lath martensite were studied by different methods. The blocks, packets and variants formed due to martensitic transformation were identified and their sizes were determined by electron backscatter diffraction (EBSD). Concomitant transmission electron microscopy (TEM) investigation revealed that the laths contain subgrains with the size between 50 and 100 nm. A novel evaluation procedure of EBSD images was elaborated for the determination of the density and the space distribution of geometrically necessary dislocations from the misorientation distribution. The total dislocation density obtained by X-ray diffraction line profile analysis was in good agreement with the value determined by EBSD, indicating that the majority of dislocations formed due to martensitic transformation during quenching are geometrically necessary dislocations.

  18. Comparison of efficacy of ferrous and iron polymaltose salts in the treatment of childhood iron deficiency anemia

    International Nuclear Information System (INIS)

    Marwat, I.U.; Hassan, K.A.; Javed, T.; Chishti, A.L.

    2013-01-01

    Iron deficiency of anemia (IDA) is defined as reduced number of red blood cells, and / or reduced concentration hemoglobin (Hb) due to deficiency of iron. Treatment involves dietary modifications and inorganic iron salt supplements like ferrous sulfate (FS) or Iron polymaltose complex (IPC). The decision to select either drug rests on therapeutic efficacy, untoward side effects; cost of complete course, patient's compliance and discretion of physician. Both drugs can be prescribed in oral form. This study aimed at comparing the efficacy of two iron preparations (ferrous sulphate and iron polymaltose complex salts) in childhood iron deficiency anemia. Objective: To compare the efficacy of Ferrous Sulphate and Iron Polymaltose Complex salts in the treatment of childhood Iron Deficiency Anemia. Methodology: This randomized controlled trial was conducted at Department of Pediatric Medicine Unit-II Mayo Hospital, Lahore, for a period of 6 months. One hundred and fifty children aged 6 months to 5 years suffering from iron deficiency anemia were selected and randomly divided into two groups of 75 each (Group A and B prescribed FS and IPC respectively). Results were analyzed in terms of rise in Hb from the baseline after three months. Increase in Hb level 2 gm/dl after three months of treatment was considered as effective. Results were analyzed by SPSS version 17. Efficacy of both the drugs, was compared by chi square test. P value 0.05 was accepted as significant. Results: There were 34 cases (22.7%) in 6-12 months age, 77 cases (51.3%) between 1-3 years age and 39 cases (26%) between 3-5 years age. The number of male and female children was 82 (54.7%) and 68 (45.3%) respectively. The baseline hemoglobin of all study cases was 6.64+-1.08 gm/dl (6.59+-1.13 gm/dl in Group A and 6.69+-1.04 gm/dl in Group B). At completion of therapy, the mean hemoglobin of all study cases was 9.15+-1.21 gm/dl (9.20+9-1.17 gm/dl in Group A and 9.11+-1.25 gm/dl in Group B). The difference

  19. Effect of zinc sulfate fortificant on iron absorption from low extraction wheat flour co-fortified with ferrous sulfate.

    Science.gov (United States)

    Olivares, Manuel; Pizarro, Fernando; López de Romaña, Daniel

    2013-03-01

    The co-fortification of wheat flour with iron (Fe) and zinc (Zn) is a strategy used to prevent these deficiencies in the population. Given that Zn could interact negatively with Fe, the objective was to assess the effect of Zn on Fe absorption from bread prepared with wheat flour fortified with Fe and graded levels of Zn fortificant. Twelve women aged 30-43 years, with contraception and a negative pregnancy test, participated in the study. They received on four different days, after an overnight fast, 100 g of bread made with wheat flour (70 % extraction) fortified with 30 mg Fe/kg as ferrous sulfate (A) or prepared with the same Fe-fortified flour but with graded levels of Zn, as zinc sulfate: 30 mg/kg (B), 60 mg/kg (C), or 90 mg/kg (D). Fe radioisotopes ((59)Fe and (55)Fe) of high specific activity were used as tracers and Fe absorption iron was measured by the incorporation of radioactive Fe into erythrocytes. The geometric mean and range of ± 1 SD of Fe absorption were: A= 19.8 % (10.5-37.2 %), B = 18.5 % (10.2-33.4 %), C = 17.7 % (7.7-38.7 %), and D = 11.2 % (6.2-20.3 %), respectively; ANOVA for repeated measures F = 5.14, p flour fortified with 30 mg/kg of Fe, as ferrous sulfate, and up to 60 mg/kg of Zn, as Zn sulfate. A statistically significant reduction of Fe absorption was observed at a Zn fortification level of 90 mg Zn/kg.

  20. Effects of fasting and/or oxidizing and reducing agents on absorption of neptunium from the gastrointestinal tract of mice and adult or neonatal rats

    International Nuclear Information System (INIS)

    Sullivan, M.F.; Ruemmler, P.S.; Ryan, J.L.

    1984-01-01

    Neptunium-237(V) nitrate was administered by gavage to groups of fed or fasted adult and 5-day-old rats. Some groups also received the oxidants quinhydrone or ferric iron and others received the reducing agent ferrous iron. Adult mice received ferric or ferrous iron and 235 Np. When the adult rats were killed at 7 days after gavage, measurements showed that, compared with rats that were fed, a 24-hr fast caused a fivefold increase in 237 Np absorption and retention. Both quinhydrone and ferric iron caused an even greater increase in absorption in both fed and fasted rats. Ferrous iron, on the other hand, decreased absorption in fasted rats to values lower than those obtained in fed rats. Similar results were obtained in mice treated with 235 Np and either ferric or ferrous iron. The effects of ferric and ferrous iron on neptunium absorption by neonatal rats were similar to their effects on adult animals but of lesser magnitude. These results are consistent with the hypothesis that Np(V), when given in small mass quantities to fed animals, is reduced in the gastrointestinal tract to Np(IV), which is less well absorbed than Np(V)

  1. Effect of Low-Dose Ferrous Sulfate vs Iron Polysaccharide Complex on Hemoglobin Concentration in Young Children With Nutritional Iron-Deficiency Anemia: A Randomized Clinical Trial.

    Science.gov (United States)

    Powers, Jacquelyn M; Buchanan, George R; Adix, Leah; Zhang, Song; Gao, Ang; McCavit, Timothy L

    2017-06-13

    Iron-deficiency anemia (IDA) affects millions of persons worldwide, and is associated with impaired neurodevelopment in infants and children. Ferrous sulfate is the most commonly prescribed oral iron despite iron polysaccharide complex possibly being better tolerated. To compare the effect of ferrous sulfate with iron polysaccharide complex on hemoglobin concentration in infants and children with nutritional IDA. Double-blind, superiority randomized clinical trial of infants and children aged 9 to 48 months with nutritional IDA (assessed by history and laboratory criteria) that was conducted in an outpatient hematology clinic at a US tertiary care hospital from September 2013 through November 2015; 12-week follow-up ended in January 2016. Three mg/kg of elemental iron once daily as either ferrous sulfate drops or iron polysaccharide complex drops for 12 weeks. Primary outcome was change in hemoglobin over 12 weeks. Secondary outcomes included complete resolution of IDA (defined as hemoglobin concentration >11 g/dL, mean corpuscular volume >70 fL, reticulocyte hemoglobin equivalent >25 pg, serum ferritin level >15 ng/mL, and total iron-binding capacity polysaccharide complex group). From baseline to 12 weeks, mean hemoglobin increased from 7.9 to 11.9 g/dL (ferrous sulfate group) vs 7.7 to 11.1 g/dL (iron complex group), a greater difference of 1.0 g/dL (95% CI, 0.4 to 1.6 g/dL; P polysaccharide complex resulted in a greater increase in hemoglobin concentration at 12 weeks. Once daily, low-dose ferrous sulfate should be considered for children with nutritional iron-deficiency anemia. clinicaltrials.gov Identifier: NCT01904864.

  2. Kinetics of Nitrite Reduction and Peroxynitrite Formation by Ferrous Heme in Human Cystathionine β-Synthase*

    Science.gov (United States)

    Carballal, Sebastián; Cuevasanta, Ernesto; Yadav, Pramod K.; Gherasim, Carmen; Ballou, David P.; Alvarez, Beatriz; Banerjee, Ruma

    2016-01-01

    Cystathionine β-synthase (CBS) is a pyridoxal phosphate-dependent enzyme that catalyzes the condensation of homocysteine with serine or with cysteine to form cystathionine and either water or hydrogen sulfide, respectively. Human CBS possesses a noncatalytic heme cofactor with cysteine and histidine as ligands, which in its oxidized state is relatively unreactive. Ferric CBS (Fe(III)-CBS) can be reduced by strong chemical and biochemical reductants to Fe(II)-CBS, which can bind carbon monoxide (CO) or nitric oxide (NO•), leading to inactive enzyme. Alternatively, Fe(II)-CBS can be reoxidized by O2 to Fe(III)-CBS, forming superoxide radical anion (O2˙̄). In this study, we describe the kinetics of nitrite (NO2−) reduction by Fe(II)-CBS to form Fe(II)NO•-CBS. The second order rate constant for the reaction of Fe(II)-CBS with nitrite was obtained at low dithionite concentrations. Reoxidation of Fe(II)NO•-CBS by O2 showed complex kinetic behavior and led to peroxynitrite (ONOO−) formation, which was detected using the fluorescent probe, coumarin boronic acid. Thus, in addition to being a potential source of superoxide radical, CBS constitutes a previously unrecognized source of NO• and peroxynitrite. PMID:26867575

  3. Synthesis and Application of Carbon–Iron Oxide Microspheres’ Black Pigments in Electrophoretic Displays

    Directory of Open Access Journals (Sweden)

    Meng Xianwei

    2010-01-01

    Full Text Available Abstract Carbon–iron oxide microspheres’ black pigments (CIOMBs had been prepared via ultrasonic spray pyrolysis of aqueous solutions containing ferrous chloride and glucose. Due to the presence of carbon, CIOMBs not only exhibited remarkably acid resistance, but also could be well dispersed in both polar solvents and nonpolar solvent. Finally, dispersions of hollow CIOMBs in tetrachloroethylene had successfully been applied in electrophoretic displays.

  4. REMOVAL OF REMAZOL ROSSO RB DYE FROM AQUEOUS EFFLUENTS BY HOMOGENOUS FENTON OXIDATION PROCESSES

    Directory of Open Access Journals (Sweden)

    Carmen Zaharia

    2014-06-01

    Full Text Available The paper presents some data from our laboratory-setup experiments of homogenous oxidative processes with hydrogen peroxide (i.e. advanced Fenton oxidation processes applied for Remazol Rosso RB dye-containing aqueous systems, especially textile effluents. Therefore, some different operating parameters (including pH, concentration of dye, H2O2 and ferrous ions, oxidation time, temperature, stirring regime, among its were tested for determination of the best performance in effluent decoloration and dye removal, meaning the optimal values of each studied parameters for highest decoloration or dye removal.

  5. Decoupling photochemical Fe(II) oxidation from shallow-water BIF deposition

    DEFF Research Database (Denmark)

    Konhauser, Kurt O.; Amskold, Larry; Lalonde, Stefan V.

    2007-01-01

    -type systems, then we are driven to conclude that oxide-facies BIF are the product of a rapid, non-photochemical oxidative process, the most likely candidates being direct or indirect biological oxidation, and that a significant fraction of BIF could have initially been deposited as ferrous minerals. ?? 2007...... the chemistry of ambient Precambrian seawater mixing with Fe(II)-rich hydrothermal fluids with, and without, UV irradiation. We find that if Fe(II) was effused from relatively shallow seamount-type vent systems directly into an anoxic photic zone, the photochemical contribution to solid-phase precipitation...... Elsevier B.V. All rights reserved....

  6. Redox Evolution in Magma Oceans Due to Ferric/Ferrous Iron Partitioning

    Science.gov (United States)

    Schaefer, L.; Elkins-Tanton, L. T.; Pahlevan, K.

    2017-12-01

    A long-standing puzzle in the evolution of the Earth is that while the present day upper mantle has an oxygen fugacity close to the QFM buffer, core formation during accretion would have occurred at much lower oxygen fugacities close to IW. We present a new model based on experimental evidence that normal solidification and differentiation processes in the terrestrial magma ocean may explain both core formation and the current oxygen fugacity of the mantle without resorting to a change in source material or process. A commonly made assumption is that ferric iron (Fe3+) is negligible at such low oxygen fugacities [1]. However, recent work on Fe3+/Fe2+ ratios in molten silicates [2-4] suggests that the Fe3+ content should increase at high pressure for a given oxygen fugacity. While disproportionation was not observed in these experiments, it may nonetheless be occurring in the melt at high pressure [5]. Therefore, there may be non-negligible amounts of Fe3+ formed through metal-silicate equilibration at high pressures within the magma ocean. Homogenization of the mantle and further partitioning of Fe2+/Fe3+ as the magma ocean crystallizes may explain the oxygen fugacity of the Earth's mantle without requiring additional oxidation mechanisms. We present here models using different parameterizations for the Fe2+/Fe3+ thermodynamic relationships in silicate melts to constrain the evolution of the redox state of the magma ocean as it crystallizes. The model begins with metal-silicate partitioning at high pressure to form the core and set the initial Fe3+ abundance. Combined with previous work on oxygen absorption by magma oceans due to escape of H from H2O [6], we show that the upper layers of solidifying magma oceans should be more oxidized than the lower mantle. This model also suggests that large terrestrial planets should have more oxidized mantles than small planets. From a redox perspective, no change in the composition of the Earth's accreting material needs to be

  7. Catalytic wet oxidative degradation of filter paper waste simulates

    International Nuclear Information System (INIS)

    Shatta, H.A.; Saleh, H.M.; Bayoumi, T.A.

    2005-01-01

    This study is part of a comprehensive research program carried out at Radioisotope Department, Atomic Energy Authority, Egypt, aiming at the treatment of organic wastes simulate to achieve acceptable weight and volume reduction. The process is based on the wet oxidative degradation of these wastes, at a laboratory scale, using hydrogen peroxide as oxidant at atmospheric pressure and at 100 degree C. The present study was concerned with the treatment of filter paper waste simulates, as one of organic wastes originating from the peaceful applications of the nuclear technology, in the presence of two types of catalysts namely; copper sulphate and ferrous sulphate. The main aim of this treatment is to achieve an acceptable weight and volume reduction. That waste was subjected to wet oxidative degradation process at atmospheric pressure and 100 degree C using 35% hydrogen peroxide as oxidant in the presence of different concentrations of ferrous sulphate or copper sulphate as catalysts. Elemental analysis and IR spectroscopy were performed for the solid residue and the secondary waste solution resulted from the treatment process to follow the degradation process. Increasing the concentration of catalyst was accompanied with an acceptable increase in the weight reduction and conversion percentages. Up to 95% total weight reduction was obtained in the case of using copper sulphate as catalyst. Also, through this technique, the organic portion of these wastes is converted to carbon dioxide and water and hence the remaining solution is considered as a form suitable for subsequent immobilization process

  8. Ferrous archaeological analogues for the understanding of the multi-secular corrosion mechanisms in an anoxic environment

    International Nuclear Information System (INIS)

    Saheb-Djahromi, M.

    2009-12-01

    Understanding the long term corrosion mechanisms of iron in an anoxic environment is essential in the field of the radioactive waste storage. In France, it is planned to store high level nuclear wastes in a multi-barrier system containing a glassy matrix surrounded by a stainless steel container, embedded in a low-carbon steel over-container. This system would be placed in a deep geological repository, which would impose anoxic conditions. As it must be efficient for a period of several thousands of years, one should understand the alteration mechanisms that are expected to occur in such a long time. To this purpose, a specific approach is developed on ferrous archaeological analogues with thick corrosion layer formed in natural conditions. In this study, the corrosion mechanisms have been assessed by examining nails aged of 400 years coming from the archaeological site of Glinet, selected as a reference site. The first point was a fine characterisation of the entire corrosion system metal / corrosion products / medium, through the use of coupled multi-scale analytical tools. The first results showed that the samples were corroded in an anoxic calco-carbonated environment. Moreover, the coupling of X-ray micro-diffraction, Raman microspectroscopy and dispersive energy spectroscopy has enabled to identify three corrosion systems composed of iron carbonates, siderite and chukanovite, and magnetite. Depending on the phase's layout in the system, the electronic resistance of the corrosion layers has been established, from resistive to conductive. In a second stage, re-corroding experiments in laboratory were performed. Firstly, the electrochemical behaviour of the corrosion system has shown that water reduction at the metallic interface is negligible. Furthermore, reaction tracing with copper and deuterium has allowed identifying the electron consumptions sites mainly localised on the external part, and the precipitation sites on the internal part of the corrosion

  9. Efficacy of fortification of school meals with ferrous glycine phosphate and riboflavin against anemia and angular stomatitis in schoolchildren.

    Science.gov (United States)

    Vinodkumar, Malavika; Rajagopalan, Srinivasa

    2009-09-01

    Multiple micronutrient deficiencies exist in many developing countries. We conducted a study to test the efficacy of ferrous glycine phosphate in reducing anemia and of riboflavin in reducing angular stomatitis when these micronutrients were added to the noon meal for schoolchildren. A pre- and post-test design was used to study children 5 to 9 years of age, with an experimental and a control group. Two schools in the same locality in Chennai were chosen for the study. The experimental school had 65 children and the control school had 71 children, all of whom consumed a noon meal at the school daily. The children in the experimental school received a powder containing ferrous glycine phosphate and riboflavin, which was added to the meal during cooking every day for 6 months. The dosage was 28 mg of elemental iron and 1 mg of riboflavin per child per day. The children attended school for 5 days each week from Monday to Friday, except for holidays; they received the fortificants on 100 days during the 6-month period. There was no intervention in the control school. Children in the experimental and control groups were matched by socioeconomic status, age, and eating habits at baseline. All the children in the experimental and control schools were dewormed at baseline and at endline after 6 months. Hemoglobin was measured by the cynamethemoglobin method at baseline and endline. Binary logistic regression showed a significant (p < .001) time x group interaction for anemia. The prevalence of anemia in the experimental school was 69.0% at baseline and 32.8% after 100 days of intervention over 6 months, a statistically significant change (p < .001). The prevalence of anemia in the control school was 91.5% at baseline and increased to 97.2% at endline; the increase was not statistically significant. The prevalence of angular stomatitis was reduced from 21% at baseline to 0% at endline in the experimental school, whereas it was 23% at baseline and 20% at endline in the

  10. Electron transfer at the mineral/water interface: Selenium reduction by ferrous iron sorbed on clay

    Science.gov (United States)

    Charlet, L.; Scheinost, A. C.; Tournassat, C.; Greneche, J. M.; Géhin, A.; Fernández-Martínez, A.; Coudert, S.; Tisserand, D.; Brendle, J.

    2007-12-01

    The mobility and availability of the toxic metalloid selenium in the environment are largely controlled by sorption and redox reactions, which may proceed at temporal scales similar to that of subsurface water movement under saturated or unsaturated conditions. Since such waters are often anaerobic and rich in Fe 2+, we investigated the long-term (⩽1 month) kinetics of selenite (Se(IV)O3-) sorption to montmorillonite in the presence of Fe 2+ under anoxic conditions. A synthetic montmorillonite was used to eliminate the influence of structural Fe. In the absence of aqueous Fe 2+, selenite was sorbed as outer-sphere sorption complex, covering only part of the positive edge sites, as verified by a structure-based MUSIC model and Se K-edge XAS (X-ray absorption spectroscopy). When selenite was added to montmorillonite previously equilibrated with Fe 2+ solution however, slow reduction of Se and formation of a solid phase was observed with Se K-edge XANES (X-ray absorption near-edge spectroscopy) and EXAFS (extended X-ray absorption fine-structure) spectroscopy. Iterative transformation factor analysis of XANES and EXAFS spectra suggested that only one Se reaction product formed, which was identified as nano-particulate Se(0). Even after one month, only 75% of the initially sorbed Se(IV) was reduced to this solid species. Mössbauer spectrometry revealed that before and after addition and reduction of Se, 5% of total sorbed Fe occurred as Fe(III) species on edge sites of montmorillonite (≈2 mmol kg -1). The only change observed after addition of Se was the formation of a new Fe(II) species (15%) attributed to the formation of an outer-sphere Fe(II)-Se sorption complex. The combined Mössbauer and XAS results hence clearly suggest that the Se and Fe redox reactions are not directly coupled. Based on the results of a companion paper, we hypothesize that the electrons produced in the absence of Se by oxidation of sorbed Fe(II) are stored, for example by formation of

  11. Iron biomineralization by anaerobic neutrophilic iron-oxidizing bacteria

    DEFF Research Database (Denmark)

    Miot, Jennyfer; Benzerara, Karim; Morin, Guillaume

    2009-01-01

    precipitation in the periplasm (in a few tens of minutes), followed by the formation of surface-bound globules. Moreover, we frequently observed an asymmetric mineral thickening at the cell poles. In parallel, the evolution of iron oxidation was quantified by STXM: iron both contained in the bacteria......Minerals formed by bio-oxidation of ferrous iron (Fe(II)) at neutral pH, their association with bacterial ultrastructures as well as their impact on the metabolism of iron-oxidizing bacteria remain poorly understood. Here, we investigated iron biomineralization by the anaerobic nitrate......-dependent iron-oxidizing bacterium Acidovorax sp. strain BoFeN1 in the presence of dissolved Fe(II) using electron microscopy and Scanning Transmission X-ray Microscopy (STXM). All detected minerals consisted mainly of amorphous iron phosphates, but based on their morphology and localization, three types...

  12. Production of ferrous sulfate from residue from the iron mining; Producao de sulfato ferroso a partir de residuo proveniente da mineracao de ferro

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, K.A; Riella, H.G.; Abreu, E.F. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engrenharia Quimica; Carvalho, E.F. Urano de; Durazzo, M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Combustivel Nuclear

    2012-11-15

    This paper was developed from a residue obtained by processing iron ore exploited by the mining company Samarco S/A. The residue was characterized and the analyses showed that it contains about 70% of the mineral hematite (Fe{sub 2}O{sub 3}) and also that some economically important products could be produced. One is the ferrous sulfate that can be used in pharmaceuticals and also that can be used in the treatment of iron deficiency anemia. The iron, in addition to is importance for the industrial production of steel and parts in general, also has great biological importance in all living beings. In order to produce ferrous sulfate from the byproduct in question, it was developed a obtaining route using metallic iron as hematite reductor and sulfuric acid to form the salt. (author)

  13. Synthesis and characterization of ferrous phosphate (vivianite) and its behavior in aqueous media; Sintesis y caracterizacion del fosfato ferroso (vivianita) y su comportamiento en medio acuoso

    Energy Technology Data Exchange (ETDEWEB)

    Diaz F, J.C

    2003-07-01

    The synthesis and characterization of materials that can be useful in Environmental Chemistry is very important because their characteristics are exposed and its behavior in chemical phenomena as the sorption in aqueous media is understand to use it in the human being benefit. With the object of using, in a future, the octa hydrated ferrous phosphate (vivianite) as a potential candidate for matrix confinement in contention walls for the storage of radioactive waste of long half life, it was synthesized and it characterized physico chemically and their properties of surface of this compound were evaluated. Presently work was carried out the synthesis and structural characterization of the iron phosphate II by infrared spectroscopy with having Fourier transform, high vacuum scanning electron microscopy, X-ray diffraction, thermal gravimetric analysis, the BET multipoint surface area and Moessbauer spectroscopy; as well as, the determination between aqueous media of the isoelectric point and the density of sites of surface of the compound. The octa hydrated ferrous phosphate was obtained pure. The results indicate that the product corresponds to the prospective mineral, the vivianite. The thermal gravimetric analysis demonstrated that the ferrous phosphate is a stable salt after the lost of water. The isoelectric point is since an important parameter because allows to know the behavior of the surface of the material in aqueous systems, in this case the isoelectric point, of the octa hydrated ferrous phosphate, in distilled water is of pH 4.20 and in solution of potassium nitrate 0.5 M is of pH = 3.75. This indicates that the material has an amphoteric surface depending on the pH. On the other hand, the density of active sites of surface obtained by titrations acid-base is of 20 sites by nm{sup 2}. (Author)

  14. Ligand binding in the ferric and ferrous states of Paramecium hemoglobin.

    Science.gov (United States)

    Das, T K; Weber, R E; Dewilde, S; Wittenberg, J B; Wittenberg, B A; Yamauchi, K; Van Hauwaert, M L; Moens, L; Rousseau, D L

    2000-11-21

    The unicellular protozoan Paramecium caudatum contains a monomeric hemoglobin (Hb) that has only 116 amino acid residues. This Hb shares the simultaneous presence of a distal E7 glutamine and a B10 tyrosine with several invertebrate Hbs. In the study presented here, we have used ligand binding kinetics and resonance Raman spectroscopy to characterize the effect of the distal pocket residues of Paramecium Hb in stabilizing the heme-bound ligands. In the ferric state, the high-spin to low-spin (aquo-hydroxy) transition takes place with a pK(a) of approximately 9.0. The oxygen affinity (P(50) = 0.45 Torr) is similar to that of myoglobin. The oxygen on- and off-rates are also similar to those of sperm whale myoglobin. Resonance Raman data suggest hydrogen bonding stabilization of bound oxygen, evidenced by a relatively low frequency of Fe-OO stretching (563 cm(-1)). We propose that the oxy complex is an equilibrium mixture of a hydrogen-bonded closed structure and an open structure. Oxygen will dissociate preferentially from the open structure, and therefore, the fraction of open structure population controls the rate of oxygen dissociation. In the CO complex, the Fe-CO stretching frequency at 493 cm(-1) suggests an open heme pocket, which is consistent with the higher on- and off-rates for CO relative to those in myoglobin. A high rate of ligand binding is also consistent with the observation of an Fe-histidine stretching frequency at 220 cm(-1), indicating the absence of significant proximal strain. We postulate that the function of Paramecium Hb is to supply oxygen for cellular oxidative processes.

  15. Empirical analyses on the development trend of non-ferrous metal industry under China’s new normal

    Science.gov (United States)

    Li, C. X.; Liu, C. X.; Zhang, Q. L.

    2017-08-01

    The CGE model of Yunnan’s macro economy was constructed based on the input-output data of Yunnan in 2012, and the development trend of the non-ferrous metals industry (NMI) under the China’s new normal was simulated. In view of this, according to different expected economic growth, and optimized economic structure, the impact on development of Yunnan NMI was simulated. The results show that the NMI growth rate is expected to decline when the economic growth show a downward trend, but the change of the proportion is relatively small. Moreover, the structure in proportion was adjusted to realize the economic structure optimization, while the proportion of NMI in GDP will decline. In contrast, the biggest influence on the NMI is the change of economic structure. From the statistics of last two years, we can see that NMI is growing, and at the same time, its proportion is declining, which is consistent with the results of simulation. But the adjustment of economic structure will take a long time. It is need to improve the proportion of deep-processing industry, extend the industrial chain, enhance the value chain, so as to be made good use of resource advantage.

  16. Porous graphite: A facile synthesis from ferrous gluconate and excellent performance as anode electrocatalyst of microbial fuel cell.

    Science.gov (United States)

    Xiong, Juan; Hu, Meihua; Li, Xiaoping; Li, Hongying; Li, Xin; Liu, Xiang; Cao, Guozhong; Li, Weishan

    2018-06-30

    A porous graphite (PG) is proposed as anode electrocatalyst of microbial fuel cell (MFC), which is synthesized by thermally decomposing ferrous gluconate followed by leaching iron. The physical characterizations from scanning electron microscopy, Brunauer-Emmett-Teller, X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy, indicate that the resulting PG is mesopore-rich and exhibits high graphitization with oxygen-containing functional groups. When evaluated on a naked carbon felt (NCF) anode, the resulting PG provides the MFC based on Escherichia coli with excellent power output. The MFC using the carbon felt anode loaded with 3.0 mg cm -2 PG delivers a maximum power density of 2.6 W m -2 , compared to the 0.2 W m -2 for the MFCs using NCF anode. This excellent performance is attributed to the electronically conductive graphite and porous structure of the resulting PG. The former provides the anode with high activity towards redox reactions of c-type cytochromes in bacteria, the latter stimulates bacteria to produce their flagella that help bacteria to firmly bond each other. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Inactivation of Escherichia coli O157 Bacteriophages by Using a Mixture of Ferrous Sulfate and Tea Extract.

    Science.gov (United States)

    Liu, Hui; Meng, Ruiqiang; Wang, Jiaying; Niu, Yan D; Li, Jinquan; Stanford, Kim; McAllister, Tim A

    2015-12-01

    Bacteriophages (phages) have been used for biocontrol of Escherichia coli O157 and other pathogenic bacteria in many different matrices and foods, but few studies have included inactivation of residual phages in culture medium before plating and enumeration of surviving host bacteria for the assessment of phage efficacy. This oversight may lead to overestimation of phage efficacy. The ability of virucidal solution containing a mixture of ferrous sulfate [iron(II) sulfate, FeSO4] and tea extract [Fe(II)T] to inactivate residual T5-like, T1-like, T4-like, and rV5-like phages was assessed using E. coli O157 as the host. At concentrations of ≥10 mM FeSO4, all phages were not detected after 20 min in a broth culture model. Compared with the virucidal solution-free samples (1 to 96% recovery), Fe(II)T (10 mM FeSO4 plus 15% tea extract) recovered a greater (P phage-treated broth culture (97 to 100% recovery) and beef samples (52 to 100% recovery). Moreover, with the addition of Fe(II)T, the number of bacteria surviving after exposure to T5-like or T4-like phages was greater (P phages. Consequently, use of a virucide for phage inactivation is recommended to improve the accuracy of evaluations of phage efficacy for biocontrol of E. coli O157.

  18. Effect of ferrous sulfate and nitrohumic acid neutralization on the leaching of metals from a combined bauxite residue.

    Science.gov (United States)

    Ren, Jie; Liu, Jidong; Chen, Juan; Liu, Xiaolian; Li, Fasheng; Du, Ping

    2017-04-01

    Bauxite residue neutralization is intended to open opportunities for revegetation and reuse of the residue. Ferrous sulfate (FS) and nitrohumic acid (NA) were two kinds of materials studied for pH reduction of the residue from 10.6 to 8.3 and 8.1, respectively. The effects of FS and NA on the leaching of metals from a combined bauxite residue were investigated by using sequential and multiple extraction procedures. Neutralization with FS and NA restricted the leaching of Al, V, and Pb from the residue but promoted the leaching of Fe, Cu, Mn, and Ni, consistent with the changes in the potentially mobile fractions. With the exceptions of Pb and Ni, leaching of metals increased during a 10-day extraction period. However, the maximum leaching of Al, V, Pb, Fe, Cu, Mn, and Ni from neutralized bauxite residue were 0.46 mg/L, 59.3, 12.9, 167, 95.3, 15.5, and 14.5 μg/L, respectively, which were under the corresponding limits in the National Standard (GB/T 14848-93). Although it is necessary to consider the continued leaching of metals during neutralization, both maximum and accumulation leaching concentrations of metals from a combined bauxite residue were too low to pose a potential environmental risk.

  19. PNGMDR 2013-2015. ANDRA's opinion on the development of sector of recycling of VLA ferrous metallic waste

    International Nuclear Information System (INIS)

    2014-01-01

    The scope of this report is to state the ANDRA's opinion on the recycling of very-low-level metallic wastes, and mainly ferrous metallic wastes which are the main stream of them. After having evoked a study jointly performed by EDF, AREVA, the CEA and the ANDRA to assess the technical and economic feasibility of a valorisation of very-low-level metallic wastes in the nuclear sector, this study proposes an assessment of ferrous metals which might be recycled over about thirty years. After having outlined the strong motivation of the ANDRA for such a recycling, the report proposes an overview of the heterogeneous stream of metallic wastes, by distinguishing scrap materials from very heterogeneous origins like those brought to the Cires storage centre, and those with more homogeneous origins (for example, from dismantling activities). The next part proposes an overview of various non coordinated initiatives, notably by the ANDRA, on different storage sites. The report identifies the keys for a successful recycling of contaminated metals in Europe, and the main challenges for the recycling of very-low-level ferrous metal in France (in competition with direct storage, and with the application of the risk-related regulation for some metallic wastes). Some proposals made by the ANDRA are then stated: a reference industrial scheme, and a coordination of actors under the auspices of the State

  20. Disilicate-Assisted Iron Electrolysis for Sequential Fenton-Oxidation and Coagulation of Aqueous Contaminants.

    Science.gov (United States)

    Cui, Jiaxin; Wang, Xu; Zhang, Jing; Qiu, Xiaoyu; Wang, Dihua; Zhao, Ying; Xi, Beidou; Alshawabkeh, Akram N; Mao, Xuhui

    2017-07-18

    Sodium disilicate (SD), an inorganic and environmentally friendly ligand, is introduced into the conventional iron electrolysis system to achieve an oxidizing Fenton process to degrade organic pollutants. Electrolytic ferrous ions, which are complexed by the disilicate ions, can chemically reduce dioxygen molecules via consecutive reduction steps, producing H 2 O 2 for the Fenton-oxidation of organics. At the near-neutral pH (from 6 to 8), the disilicate-Fe(II) complexes possess strong reducing capabilities; therefore, a near-neutral pH rather than an acid condition is preferable for the disilicate-assisted iron electrolysis (DAIE) process. Following the DAIE process, the different complexing capacities of disilicate for ferrous/ferric ions and calcium ions can be used to break the disilicate-iron complexes. The addition of CaO or CaCl 2 can precipitate ferrous/ferric ions, disilicates and possibly heavy metals in the wastewater. Compared to previously reported organic and phosphorus ligands, SD is a low-cost inorganic agent that does not lead to secondary pollution, and would not compete with the target organic pollutants for •OH; therefore, it would greatly expand the application fields of the O 2 activation process. The combination of DAIE and CaO treatments is envisioned to be a versatile and affordable method for treating wastewater with complicated pollutants (e.g., mixtures of biorefractory organics and heavy metals).

  1. Effectiveness of two programs of intermittent ferrous supplementation for treating iron-deficiency anemia in infants: randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Geraldo Gaspar Paes Leme Coutinho

    Full Text Available CONTEXT AND OBJECTIVE: Low compliance among mothers regarding the treatment of anemic children using daily doses of ferrous sulfate administered at home has been reported. This study aimed to establish the effectiveness of weekly doses administered by mothers at home compared with weekly supplements administered directly by healthcare professionals, to reduce the prevalence of anemia. DESIGN AND SETTING: This was a randomized clinical trial at a public healthcare clinic in São José do Rio Preto, Brazil. METHODS: This iron supplementation study was carried out using two intervention groups. The sample population was 130 infants, randomly allocated to two groups of 65 children. All of them received 12 weekly doses of 25 mg of elemental iron, administered either in the public healthcare clinic or at their homes. RESULTS: Treatment compliance was shown in both groups. The prevalence of anemia among all of the children was 75% at the beginning of supplementation and 46.3% at the end of the period (P < 0.0005, corresponding to a reduction in the number of anemic children of 38.3%. The average increases in hemoglobin concentration levels were 0.75 g/dl and 0.65 g/dl, respectively for home interventions and healthcare clinic administration (P < 0.00005. CONCLUSION: Weekly supplementation of 25 mg of iron was proven to be efficient in reducing anemia, using interventions both at home and in healthcare clinics. Compliance among the mothers was achieved because weekly supplementation was easy to administer and had few side effects. The results showed that the treatment presented low cost and fast benefits.

  2. On the use of a novel Ferrous Xylenol-orange gelatin dosimeter for HDR brachytherapy commissioning and quality assurance testing.

    Science.gov (United States)

    Pappas, Eleftherios P; Peppa, Vasiliki; Hourdakis, Costas J; Karaiskos, Pantelis; Papagiannis, Panagiotis

    2018-01-01

    To evaluate a commercially available Ferrous-Xylenol Orange-Gel (FXG) dosimeter (TrueView™) coupled with Optical-Computed Tomography (OCT) read out, for 3D dose verification in an Ir-192 superficial brachytherapy application. Two identical polyethylene containers filled with gel from the same batch were used. One was irradiated with an 18 MeV electron field to examine the dose-response linearity and obtain a calibration curve. A flap surface applicator was attached to the other to simulate treatment of a skin lesion. The dose distribution in the experimental set up was calculated with the TG-43 and the model based dose calculation (MBCA) algorithms of a commercial treatment planning system (TPS), as well as Monte Carlo (MC) simulation using the MCNP code. Measured and calculated dose distributions were spatially registered and compared. Apart from a region close to the container's neck, where gel measurements exhibited an over-response relative to MC calculations (probably due to stray light perturbation), an excellent agreement was observed between measurements and simulations. More than 97% of points within the 10% isodose line (80 cGy) met the gamma index criteria established from uncertainty analysis (5%/2 mm). The corresponding passing rates for the comparison of experiment to calculations using the TG-43 and MBDCA options of the TPS were 57% and 92%, respectively. TrueView™ is suitable for the quality assurance of demanding radiotherapy applications. Experimental results of this work confirm the advantage of the studied MBDCA over TG-43, expected from the improved account of scatter radiation in the treatment geometry. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  3. Activated persulfate oxidation as a first step in a treatment train

    DEFF Research Database (Denmark)

    Tsitonaki, Aikaterini; Mosbæk, Hans; Bjerg, Poul Løgstrup

    2006-01-01

    the efficiency of activated persulfate oxidation against MTBE, Trichloroethylene (TCE) and 1,1,1-Trichloroethane (TCA) in both aqueous and soil-water systems using heat and ferrous ion as activators. Heat-activated persulfate oxidation at 40oC was the most effective method and achieved 98.6% removal of MTBE......, and 89.9% of TCE in the soil-water systems within 24 hours. Considerable TCA removal was only observed in the aqueous systems. Iron-activated persulfate was very effective in the first hours but its efficiency was thereafter limited. Further experiments with MTBE and the use of complexing agents...

  4. Treatment of Some Hazardous Industrial Pollutants by Simple Oxidation Techniques

    International Nuclear Information System (INIS)

    Abd El-Rahman, N.M.

    1999-01-01

    Central treatment of Industrial wastewater requires pretreatment of some specific pollutants which may be not effectively degraded in down stream processes in central treatment unit. Some of the hazardous pollutants in industrial wastewater including acrylonitrile, pesticides and some commonly used dyes (active and acid dyes) have been subjected individually to oxidation using hydrogen peroxide catalyzed by ferrous ions in acidic solution. Treatment efficiency was monitored by chemical oxygen demand (COD) removal using a specially developed concentration/COD curves. Initial concentrations (in terms of COD) were 910 PPM, 1348 and 530 ppm and the respective COD reductions were 91, 98 and 99%, for the pesticide, acrylonitrile and the reactive dye. Oxidative degradation of polared and acid green also reduced COD by 99 and 100% respectively. The obtained results confirm the appropriateness of oxidative degradation as a pretreatment for some hazardous pollutants prior to treatment in central facilities or municipal activated sludge stations

  5. Impacts of operating parameters on oxidation-reduction potential and pretreatment efficacy in the pretreatment of printing and dyeing wastewater by Fenton process.

    Science.gov (United States)

    Wu, Huifang; Wang, Shihe

    2012-12-01

    An experiment was conducted in a batch reactor for a real printing and dyeing wastewater pretreatment using Fenton process in this study. The results showed that original pH, hydrogen peroxide concentration and ferrous sulfate concentration affected ORP value and pretreatment efficacy greatly. Under experimental conditions, the optimal original pH was 6.61, and the optimal hydrogen peroxide and ferrous sulfate concentrations were 1.50 and 0.75 gL(-1), respectively. The relationship among ORP, original pH, hydrogen peroxide concentration, ferrous sulfate concentration, and color (COD or BOD(5)/COD) was established, which would be instructive in on-line monitoring and control of Fenton process using ORP. In addition, the effects of wastewater temperature and oxidation time on pretreatment efficacy were also investigated. With an increase of temperature, color and COD removal efficiencies and BOD(5)/COD ratio increased, and they were in proportion to the exponent of temperature reciprocal. Similarly, color and COD removal efficiencies increased with increasing oxidation time, and both color and COD removal obeyed the first-order kinetics. The BOD(5)/COD ratio could be expressed by a second-degree polynomial with respect to oxidation time, and the best biodegradability of wastewater was present at the oxidation time of 6.10h. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Prophylaxis for iron deficiency anemia using ferrous sulfate among infants followed up at a primary healthcare unit in the municipality of Embu-SP (2003/2004

    Directory of Open Access Journals (Sweden)

    André Fernando Shibukawa

    Full Text Available CONTEXT AND OBJECTIVE: Iron deficiency anemia is an important public health problem in Brazil. In the municipality of Embu, a population study in 1996 found anemia prevalence of 68.5% among children aged one to two years. From these data, prescription of prophylactic ferrous sulfate was instituted in 1998 for children under two years old followed up within the children's healthcare program. After five years of intervention, the prevalence of anemia and associated factors were investigated among children aged 12 to 18 months to whom guidance for prophylactic ferrous sulfate use had been given. DESIGN AND SETTING: Cross-sectional study covering October 2003 to June 2004 at a primary healthcare unit in Embu. METHODS: A randomized sample of children aged 12 to 18 months to whom guidance for prophylactic ferrous sulfate use had been given was obtained. Hemoglobin was measured in capillary blood, using HemoCue® apparatus. Hemoglobin < 11 g/100 dl was taken to indicate anemia. RESULTS: The sample comprised 118 children and anemia was found in 41.5%. There was no statistically significant association between anemia presence and the variables of sex, birth weight, neonatal intercurrences, chronic diseases, breastfeeding or iron supplementation use. There was a statistically significant association (p = 0.03 between anemia presence and per capita income, such that the higher the income was, the lower the prevalence of anemia was. CONCLUSION: The prophylaxis program against iron deficiency anemia did not achieve the expected results. New strategies must be considered in the light of the magnitude of the problem.

  7. Both immanently high active iron contents and increased root ferrous uptake in response to low iron stress contribute to the iron deficiency tolerance in Malus xiaojinensis.

    Science.gov (United States)

    Zha, Qian; Wang, Yi; Zhang, Xin-Zhong; Han, Zhen-Hai

    2014-01-01

    To better understand the mechanism of low-iron stress tolerance in Malus xiaojinensis, the differences in physiological parameters and gene expression between an iron deficiency-sensitive species, Malus baccata, and an iron deficiency-tolerant species, M. xiaojinensis were investigated under low-iron (4 μM Fe) conditions. Under iron sufficient conditions, the expressions of iron uptake- and transport-related genes, i.e. FIT1, IRT1, CS1, FRD3 and NRMAP1, and the immanent leaf and root active iron contents were higher in M. xiaojinensis than those in M. baccata. However, on the first three days of low iron stress, the rhizospheric pH decreased and the root ferric chelate reductase (FCR) activity and the expression of ferrous uptake- and iron transport-related genes in the roots increased significantly only in M. xiaojinensis. Leaf chlorosis occurred on the 3rd and the 9th day after low-iron treatment in M. baccata and M. xiaojinensis, respectively. The expression of iron relocalization-related genes, such as NAS1, FRD3 and NRMAP3, increased after the 5th or 6th day of low iron stress in leaves of M. xiaojinensis, whereas the expression of NAS1, FRD3 and NRMAP3 in the leaves of M. baccata increased immediately after the onset of low iron treatment. Conclusively, the relative high active iron contents caused by the immanently active root ferrous uptake and the increased root ferrous uptake in response to low iron stress were the dominant mechanisms for the tolerance to iron deficiency in M. xiaojinensis. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  8. Human biomonitoring of heavy metals in the vicinity of non-ferrous metal plants in Ath, Belgium

    Directory of Open Access Journals (Sweden)

    Sébastien Fierens

    2016-10-01

    Full Text Available Abstract Background A previous study revealed an environmental contamination by heavy metals in the vicinity of two non-ferrous metal plants in Ath, Belgium. The purpose of the current cross-sectional study was to estimate exposure of the population to heavy metals in the vicinity of the plants, in comparison with population living further away. Methods We did a random sampling in the general population of Ath in two areas: a central area, including the plants, and a peripheral area, presumably less exposed. We quantified cadmium, lead, nickel, chromium and cobalt in blood and/or urine of children and adults in three age groups: (i children aged 2.5 to 6 years (n = 98, (ii children aged 7 to 11 years (n = 74, and (iii adults aged 40 to 60 years (n = 106. We also studied subclinical health effects by quantifying retinol-binding protein and microalbuminuria, and by means of a Strengths and Difficulties Questionnaire. Results We obtained a participation rate of 24 %. Blood lead levels were significantly higher in young children living in the central area (18.2 μg/l ; 95 % CI: 15.9–20.9 compared to the peripheral area (14.8 μg/l ; 95 % CI: 12.6–17.4. We observed no other significant mean difference in metal concentrations between the two areas. In the whole population, blood lead levels were higher in men (31.7 μg/l ; 95 % CI: 27.9–36.1 than in women (21.4 μg/l ; 95 % CI: 18.1–25.3. Urine cadmium levels were 0.06 μg/g creatinine (95 % CI: 0.05–0.07, 0.21 μg/g creatinine (95 % CI: 0.17–0.27, and 0.25 μg/g creatinine (95 % CI: 0.20–0.30 for children, men, and women, respectively. Conclusions Despite higher blood lead levels in young children living close to the plants, observed metal concentrations remain in the range found in other similar biomonitoring studies in the general population and are below the levels of concern for public health.

  9. Metallurgical aspects of welding. Ferrous and nonferrous materials. 4. new rev. ed.; Die Metallurgie des Schweissens. Eisenwerkstoffe - nichteisenmetallische Werkstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, Guenter

    2010-07-01

    This is the fourth edition of the standard work on welding metallurgy. The various problems of ferrous and nonferrous materials in the welding process are presented in great detail. In order to prevent corrosion of welded constructions, metallurgical properties and problems of all important technical materials are discussed, i.e. alloyed and unalloyed steels, cast iron materials, and the most relevant nonferrous materials. At the end of each chapter, the interested reader will find exercises for self-studies. Some of these can be solved using the material presented in the book while others are intended for deepening and further training. Easy examples (with solutions) are found all over the book; they are helpful because they provide information on underlying mechanisms and interdependences that are not obvious at first glance. The information was adapted to new EURO standards and international standards (up to March 2009) as far as these are relevant to Germany. New information is provided, e.g., on new steel standards (constructional steels according to DIN EN 10025), heat-treatable steels according to DIN EN 10025-6 and DIN EN 10083, high-alloy steels according to DIN EN 10088, and filler materials for steel welding according to DIN EN ISO 2560. The systematics of the ''law of cohabitation'' was applied to welding engineering for the first time here. (orig.) [German] Das in vierter Auflage erscheinende Buch widmet sich der Schweissmetallurgie mit ihren Besonderheiten. Die vielfaeltigen Probleme der Eisenwerkstoffe und der nichteisenmetallischen Werkstoffe bei ihrer schweisstechnischen Verarbeitung werden ausfuehrlich dargestellt. Um Korrosionsschaeden an geschweissten Konstruktionen vorzubeugen, wird die Metallurgie aller technisch bedeutsamen Werkstoffe, wie unlegierte und legierte Staehle, Eisen-Gusswerkstoffe, die wichtigsten NE-Metalle, ausfuehrlich besprochen. An den Kapitelenden findet der interessierte Leser Aufgaben, von denen ein

  10. Mechanisms of the multi-secular atmospheric corrosion of ferrous alloys: The case of the Metz cathedral reinforcements

    International Nuclear Information System (INIS)

    Bouchar, Marie

    2015-01-01

    The study of the mechanisms of the multi-secular atmospheric corrosion of ferrous alloys has various applications, from the preservation and restoration of cultural heritage metals, to the evaluation of their long term behaviour, specifically when they are used for the storage containers surrounding nuclear wastes. The study of the corrosion product layers (CPL) developed during 5 centuries on the Metz cathedral reinforcements brings new results for a better understanding of the complex processes involved in the formation of the atmospheric CPL. The phases and chemical elements constituting the CPL of these reinforcements were characterized at the micrometric scale (μDRX, Raman μ-spectroscopy (μRS), SEM-EDS). Results specifically showed that these CPL differ from other multi-secular systems previously studied by their very high content in ferri-hydrite (5Fe 2 O 3 , 9H 2 O). This very reactive phase is distributed in the whole CPL and mixed at the microscopic scale with goethite (a-FeOOH) and lepidocrocite (g-FeOOH). Diffusion experiments of bromide ions followed by in situ X-ray μ-fluorescence allowed a better understanding of the transport of dissolved species in the porous network of the CPL. Furthermore, a test of the corrosion system behavior in conditions simulating the wetting stage of the RH cycle of atmospheric corrosion, also followed in situ by μRS, highlighted the reduction of ferri-hydrite at the metal/CPL interface. These results allowed to verify for the first time a fundamental hypothesis about the mechanisms of very long term atmospheric corrosion. Finally, re-corrosion experiments of the corrosion system were monitored in a climatic chamber simulating accelerated atmospheric cycles in an 18 O-labelled environment. Then the detection of the 18 O isotope linked to the precipitated phases, by nuclear reaction analysis using a nuclear microprobe, allowed to localise the formation sites of the new corrosion products. All these results improve the

  11. Photoinduced Oxidation of Arsenite to Arsenate on Ferrihydrite

    Energy Technology Data Exchange (ETDEWEB)

    N Bhandari; R Reeder; D Strongin

    2011-12-31

    The photochemistry of an aqueous suspension of the iron oxyhydroxide, ferrihydrite, in the presence of arsenite has been investigated using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray absorption near edge structure (XANES), and solution phase analysis. Both ATR-FTIR and XANES show that the exposure of ferrihydrite to arsenite in the dark leads to no change in the As oxidation state, but the exposure of this arsenite-bearing surface, which is in contact with pH 5 water, to light leads to the conversion of the majority of the adsorbed arsenite to the As(V) bearing species, arsenate. Analysis of the solution phase shows that ferrous iron is released into solution during the oxidation of arsenite. The photochemical reaction, however, shows the characteristics of a self-terminating reaction in that there is a significant suppression of this redox chemistry before 10% of the total iron making up the ferrihydrite partitions into solution as ferrous iron. The self-terminating behavior exhibited by this photochemical arsenite/ferrihydrite system is likely due to the passivation of the ferrihydrite surface by the strongly bound arsenate product.

  12. Roles of Glutamates and Metal ions in a Rationally Designed Nitric Oxide Reductase Based on Myoglobin

    Energy Technology Data Exchange (ETDEWEB)

    Y Lin; N Yeung; Y Gao; K Miner; S Tian; H Robinson; Y Lu

    2011-12-31

    A structural and functional model of bacterial nitric oxide reductase (NOR) has been designed by introducing two glutamates (Glu) and three histidines (His) in sperm whale myoglobin. X-ray structural data indicate that the three His and one Glu (V68E) residues bind iron, mimicking the putative FeB site in NOR, while the second Glu (I107E) interacts with a water molecule and forms a hydrogen bonding network in the designed protein. Unlike the first Glu (V68E), which lowered the heme reduction potential by {approx}110 mV, the second Glu has little effect on the heme potential, suggesting that the negatively charged Glu has a different role in redox tuning. More importantly, introducing the second Glu resulted in a {approx}100% increase in NOR activity, suggesting the importance of a hydrogen bonding network in facilitating proton delivery during NOR reactivity. In addition, EPR and X-ray structural studies indicate that the designed protein binds iron, copper, or zinc in the FeB site, each with different effects on the structures and NOR activities, suggesting that both redox activity and an intermediate five-coordinate heme-NO species are important for high NOR activity. The designed protein offers an excellent model for NOR and demonstrates the power of using designed proteins as a simpler and more well-defined system to address important chemical and biological issues.

  13. Quality- and dilution losses in the recycling of ferrous materials from end-of-life passenger cars: input-output analysis under explicit consideration of scrap quality.

    Science.gov (United States)

    Nakamura, Shinichiro; Kondo, Yasushi; Matsubae, Kazuyo; Nakajima, Kenichi; Tasaki, Tomohiro; Nagasaka, Tetsuya

    2012-09-04

    Metals can in theory be infinitely recycled in a closed-loop without any degradation in quality. In reality, however, open-loop recycling is more typical for metal scrap recovered from end-of-life (EoL) products because mixing of different metal species results in scrap quality that no longer matches the originals. Further losses occur when meeting the quality requirement of the target product requires dilution of the secondary material by adding high purity materials. Standard LCA usually does not address these losses. This paper presents a novel approach to quantifying quality- and dilution losses, by means of hybrid input-output analysis. We focus on the losses associated with the recycling of ferrous materials from end-of-life vehicle (ELV) due to the mixing of copper, a typical contaminant in steel recycling. Given the quality of scrap in terms of copper density, the model determines the ratio by which scrap needs to be diluted in an electric arc furnace (EAF), and the amount of demand for EAF steel including those quantities needed for dilution. Application to a high-resolution Japanese IO table supplemented with data on ferrous materials including different grades of scrap indicates that a nationwide avoidance of these losses could result in a significant reduction of CO(2) emissions.

  14. Analytical applications of condensed phosphoric acid-I Determination of ferrous and total iron in iron ores after decomposition with condensed phosphoric acid.

    Science.gov (United States)

    Mizoguchi, T; Ishii, H

    1978-06-01

    A simple method is described for the determination of ferrous and total iron in iron ores. Iron ores are dissolved by condensed phosphoric acid (CPA) very rapidly without any tedious and time-consuming manipulations such as elimination of silica and filtration. Under the proposed conditions (amount of sample 100 mg, amount of CPA added 10 g, heating temperature 290 degrees , heating time 30 min), magnetite, limonite and hematite are completely dissolved. The iron content can be determined in the presence of condensed phosphoric acid by titration with dichromate solution, if a slight modification is made. The total iron in iron ores, determined by the present method, is in agreement with that found by the JIS method. The ferrous iron in iron ores can be determined by dissolving the samples with CPA in a nitrogen atmosphere and titrating with dichromate solution. Chelatometric titration of iron after solvent extraction with MIBK from solutions prepared by use of CPA is found to be accurate for samples such as pyrite cinder. The ability of CPA to dissolve various materials has been investigated.

  15. Verification of absorbed doses determined with thimble and plane-parallel ionization chambers in clinical electron beams using ferrous sulphate dosimetry

    International Nuclear Information System (INIS)

    Thierens, H.

    1992-09-01

    Different ionometric methods to determine absorbed dose in phantoms irradiated with electron beams were tested using ferrous sulphate dosimetry as a reference method. Irradiation was carried out with three different types of accelerators in the energy range 4 to 20 MeV. Three different types of plane parallel ionization chambers were used and two types of cylindrical chambers. It was found that the ionization chamber dosimetry following the International Code of Practice (TRS 277) gave dose values as a mean 0.6% higher than the ferrous sulphate dosimetry based on the ICRU report 35. There were no significant differences between results measured at different electron energies. The mean deviation obtained using the two dosimeter systems is inside the experimental uncertainty. This proves that the TRS 277 can be used for accurate dosimetry. Further, the results show that corrections are needed for some types of plane parallel plate chambers to correct for the perturbation by the chamber of the electron fluence in the water phantom, and that values of these corrections are given as a function of the electron energy. 14 refs, 4 figs, 2 tabs

  16. Kinetic modeling for thermal dehydration of ferrous oxalate dihydrate polymorphs: a combined model for induction period-surface reaction-phase boundary reaction.

    Science.gov (United States)

    Ogasawara, Haruka; Koga, Nobuyoshi

    2014-04-03

    In this study, ferrous oxalate dihydrate polymorph particles, α- and β-phases, with square bipyramidal and quadratic prismatic shapes, respectively, were synthesized. Thermal dehydration of the samples was subjected to kinetic study as a typical reaction that indicates a significant induction period and a sigmoidal mass-loss behavior. On the basis of the formal kinetic analysis of the mass-loss traces recorded under isothermal, nonisothermal, and constant transformation rate conditions and the morphological observations of the surface textures of the partially reacted sample particles, a combined kinetic model for the induction period-surface reaction-phase boundary reaction was developed. The sigmoidal mass-loss behavior after the significant induction period under isothermal conditions was satisfactorily simulated by the combined kinetic model. The kinetic parameters for the component processes of induction period, surface reaction, and phase boundary reaction were separately determined from the kinetic simulation. The differences in the kinetic behaviors of the induction period and the phase boundary reaction between α- and β-phase samples were well described by the kinetic parameters. The applicability of the combined kinetic model to practical systems was demonstrated through characterizing the physicogeometrical kinetics of the thermal dehydration of ferrous oxalate dihydrate polymorphs.

  17. Influence of mechanical activation on the leaching of non-ferrous metals from a CuPbZn complex concentrate

    Directory of Open Access Journals (Sweden)

    Godoèíková Erika

    2000-09-01

    Full Text Available The aim of study was to research the procedures of copper, lead and zinc leaching from CuPbZn complex sulphide concentrate during the intervention of mechanical activation.Mechanical activation belongs to innovative procedures, which intensifies technological processes by means of creation of new surfaces and making defective structure of solid phase. Mechanical impact on the solid phase is a suitable procedure to ensure the mobility of its structure elements and to accumulate the mechanical energy that is later used in following processes of leaching.This paper deals with the intensification of the chloride and thiourea leaching of copper, lead and zinc from a CuPbZn complex concentrate of Hodruša-Hámre (Slovak deposit by using the mechanical activation in an attritor. Ferric chloride and thiourea were used as leaching reagents. The leaching of the concentrate with ferric chloride solution afforded 23 % recovery of Cu, 99 % of Pb and 28 % of Zn. 9 % recovery of Cu, 17 % of Pb and 3 % of Zn were achieved by the leaching with thiourea. Thus results showed that the extraction of Cu, Zn and also Pb in the case of thiourea leaching was low. The use of milling in the attritor as an innovation method of pretreatment leads to the structural degradation and increasing the surface area of the investigated concentrate from the original value of 0.18 m2g-1 to the maximum value of 4.67 m2g-1. This fact manifested itself in the subsequent process of extraction of Cu, Pb and Zn into the chloride and thiourea solutions. Our results indicate more effective leaching of pretreated concentrate in the chloride medium with recoveries of 84 % Zn and 100 % Pb. In thiourea, the recoveries for Zn and Pb were low, however 99 % Cu can be recovered. In regard to the economy, the extraction of Cu, Pb and Zn was studied in this work with the aspect of minimal energy consumption during milling. The maximum recoveries of non-ferrous metals in the solutions of ferric chloride

  18. The role of iron species on the turbidity of oxidized phenol solutions in a photo-Fenton system.

    Science.gov (United States)

    Villota, Natalia; Camarero, Luis M; Lomas, Jose M; Perez-Arce, Jonatan

    2015-01-01

    This work aims at establishing the contribution of the iron species to the turbidity of phenol solutions oxidized with photo-Fenton technology. During oxidation, turbidity increases linearly with time till a maximum value, according to a formation rate that shows a dependence of second order with respect to the catalyst concentration. Next, the decrease in turbidity shows the evolution of second-order kinetics, where the kinetics constant is inversely proportional to the dosage of iron, of order 0.7. The concentration of iron species is analysed at the point of maximum turbidity, as a function of the total amount of iron. Then, it is found that using dosages FeT=0-15.0 mg/L, the majority iron species was found to be ferrous ions, indicating that its concentration increases linearly with the dosage of total iron. This result may indicate that the photo-reaction of ferric ion occurs leading to the regeneration of ferrous ion. The results, obtained by operating with initial dosages FeT=15.0 and 25.0 mg/L, suggest that ferrous ion concentration decreases while ferric ion concentration increases in a complementary manner. This fact could be explained as a regeneration cycle of the iron species. The observed turbidity is generated due to the iron being added as a catalyst and the organic matter present in the system. Later, it was found that at the point of maximum turbidity, the concentration of ferrous ions is inversely proportional to the concentration of phenol and its dihydroxylated intermediates.

  19. The glassy behaviour of poorly crystalline Fe2O3 nanorods obtained by thermal decomposition of ferrous oxalate

    Czech Academy of Sciences Publication Activity Database

    Perović, M.; Kusigerski, V.; Mrakovic, A.; Spasojevic, V.; Blanusa, J.; Nikolic, V.; Schneeweiss, Oldřich; David, Bohumil; Pizúrová, Naděžda

    2015-01-01

    Roč. 26, č. 11 (2015), Art. n. 115705 ISSN 0957-4484 Institutional support: RVO:68081723 Keywords : Thermal decomposition * Nanorods * Iron oxide * Spin glass like * Memory effects Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.573, year: 2015

  20. Kinetics of the electrolytic Fe+2/Fe+3 oxidation on various anode materials

    Directory of Open Access Journals (Sweden)

    Cifuentes, L.

    2003-08-01

    Full Text Available The kinetics of the electrolytic Fe+2/Fe+3 oxidation, relevant to hydro-electrometallurgical processing, have been studied on lead, platinum, ruthenium oxide, iridium oxide and graphite anodes in ferrous sulfate-sulfuric acid solutions. The oxidation rate depends on ferrous sulfate concentration, solution temperature and degree of agitation. Potentiodynamic studies show that: a the highest oxidation rate is obtained on platinum; b lead is unsuitable as anodic material for the said reaction; c the remaining anode materials show a similar and satisfactory performance.

    Se ha estudiado la cinética de la oxidación electrolítica Fe+2/Fe+3 -relevante para el procesamiento hidroelectrometalúrgico- sobre plomo, platino, óxido de rutenio, óxido de iridio y grafito en soluciones de sulfato ferroso en ácido sulfúrico. La velocidad de oxidación depende de la concentración de sulfato ferroso, la temperatura de la solución y el grado de agitación. Estudios potenciodinámicos demuestran que: a las mayores velocidades de oxidación se obtienen sobre platino; b el plomo es inadecuado como material anódico para la reacción mencionada; c los materiales anódicos restantes exhiben un desempeño similar y satisfactorio.

  1. [Effectiveness of iron amino acid chelate versus ferrous sulfate as part of a food complement in preschool children with iron deficiency, Medellín, 2011].

    Science.gov (United States)

    Rojas, Maylen Liseth; Sánchez, Juliana; Villada, Óscar; Montoya, Liliana; Díaz, Alejandro; Vargas, Cristian; Chica, Javier; Herrera, Ana Milena

    2013-01-01

    Iron depleted deposits are the first link in the chain of events leading to iron deficiency which is the most prevalent nutritional shortage and main cause of anemia worldwide. This situation can be prevented through food fortification. To compare the efficacy of amino acid chelate iron with ferrous sulfate as fortifier of a dietary complement in preschoolers with iron deficiency. This study was a blinded clinical trial with randomized groups. We analyzed 56 preschoolers with iron deficiency (ferritin children had respiratory tract infection, without statistical differences. Both compounds increased serum ferritin concentration, with a higher increase in those who were given milk with iron amino acid chelate. There were no differences in the adverse reactions and infections incidences between the groups.

  2. Investigating of the Knocking Out Properties of Moulding Sands with New Inorganic Binders Used for Castings of Non-ferrous Metal Alloys in Comparison with the Previously Used

    Directory of Open Access Journals (Sweden)

    I. Izdebska-Szanda

    2012-12-01

    Full Text Available The article presents the results of investigations, which make a fragment of the broad-scale studies carried out as a part of the projectPOIG.01.01.02-00-015/09 “Advanced materials and technologies”.One of the objectives of the introduction of new inorganic binders is to provide a good knocking out properties of moulding sands, whilemaintaining an appropriate level of strength properties.Therefore, a logical continuation of the previous studies were carried out the tests knocking out properties of moulding sands with newinorganic binders, including making moulds, pouring them by the chosen of non-ferrous metal alloys, knoking-out, and determining theknocking out work.The results of the study were related to the research results obtained by applying the moulding sand performed by existing technology.

  3. Bioavailability of elemental iron powders to rats is less than bakery-grade ferrous sulfate and predicted by iron solubility and particle surface area.

    Science.gov (United States)

    Swain, James H; Newman, Samuel M; Hunt, Janet R

    2003-11-01

    Foods are fortified with elemental forms of iron to reduce iron deficiency. However, the nutritional efficacy of current, commercially produced elemental iron powders has not been verified. We determined the bioavailability of six commercial elemental iron powders and examined how physicochemistry influences bioavailability. Relative biological value (RBV) of the iron powders was determined using a hemoglobin repletion/slope ratio method, treating iron-deficient rats with repletion diets fortified with graded quantities of iron powders, bakery-grade ferrous sulfate or no added iron. Iron powders were assessed physicochemically by measuring iron solubility in hydrochloric acid at pH 1.0 and 1.7, surface area by nitrogen gas adsorption and surface microstructure by electron microscopy. Bioavailability from the iron powders, based on absolute iron intake, was significantly less than from FeSO4 (100%; P Electrolytic (54%; A-131, U.S.) > Electrolytic (46%; Electrolytic Iron, India) > H-Reduced (42%; AC-325, U.S.) > Reduced (24%; ATOMET 95SP, Canada) > CO-Reduced (21%; RSI-325, Sweden). Solubility testing of the iron powders resulted in different relative rankings and better RBV predictability with increasing time at pH 1.7 (R2 = 0.65 at 150 min). The prediction was improved with less time and lower pH (R2 = 0.82, pH 1.0 at 30 min). Surface area, ranging from 90 to 370 m2/kg, was also highly predictive of RBV (R2 = 0.80). Bioavailability of iron powders is less than bakery-grade ferrous sulfate and varies up to three times among different commercial forms. Solubility at pH 1.0 and surface area were predictive of iron bioavailability in rats.

  4. Integrated bio-oxidation and adsorptive filtration reactor for removal of arsenic from wastewater.

    Science.gov (United States)

    Kamde, Kalyani; Dahake, Rashmi; Pandey, R A; Bansiwal, Amit

    2018-01-08

    Recently, removal of arsenic from different industrial effluent discharged using simple, efficient and low-cost technique has been widely considered. In this study, removal of arsenic (As) from real wastewater has been studied employing modified bio-oxidation followed by adsorptive filtration method in a novel continuous flow through the reactor. This method includes biological oxidation of ferrous to ferric ions by immobilized Acidothiobacillus ferrooxidans bacteria on granulated activated carbon (GAC) in fixed bed bio-column reactor with the adsorptive filtration unit. Removal efficiency was optimized regarding the initial flow rate of media and ferrous ions concentration. Synthetic wastewater sample having different heavy metal ions such as Arsenic (As), Cobalt (Co), Chromium (Cr), Copper (Cu), Iron (Fe), Lead (Pb) and Manganese (Mn) were also used in the study. The structural and surface changes occurring after the treatment process were scrutinized using FT-IR and Scanning Electron Microscopy (SEM) analysis. The finding showed that not only arsenic can be removed considerably in the bioreactor system, but also removing efficiency was much more (metals in real wastewater sample. The results from TCPL test confirms that solid spent media was non-hazardous and can be safely disposed of. This study verified that combination of bio-oxidation with adsorptive filtration method improves the removal efficiency of arsenic and other heavy metal ions in wastewater sample.

  5. Ethylene Oxide

    Science.gov (United States)

    Learn about ethylene oxide, which can raise your risk of lymphoma and leukemia. Exposure may occur through industrial emissions, tobacco smoke, and the use of products sterilized with ethylene oxide, such as certain medical products or cosmetics.

  6. The Pathophysiology of Extracellular Hemoglobin Associated with Enhanced Oxidative Reactions

    Directory of Open Access Journals (Sweden)

    Joseph M Rifkind

    2015-01-01

    Full Text Available Hemoglobin (Hb continuously undergoes autoxidation producing superoxide which dismutates into hydrogen peroxide (H2O2 and is a potential source for subsequent oxidative reactions. Autoxidation is most pronounced under hypoxic conditions in the microcirculation and for unstable dimers formed at reduced Hb concentrations. In the red blood cell (RBC, oxidative reactions are inhibited by an extensive antioxidant system. For extracellular Hb, whether from hemolysis of RBCs and/or the infusion of Hb-based blood substitutes, the oxidative reactions are not completely neutralized by the available antioxidant system. Un-neutralized H2O2 oxidizes ferrous and ferric Hbs to Fe(IV-ferrylHb and oxyferrylHb, respectively. FerrylHb further reacts with H2O2 producing heme degradation products and free iron. OxyferrylHb, in addition to Fe(IV contains a free radical that can undergo additional oxidative reactions. Fe(IIIHb produced during Hb autoxidation also readily releases heme, an additional source for oxidative stress. These oxidation products are a potential source for oxidative reactions in the plasma, but to a greater extent when the lower molecular weight Hb dimers enter cells and tissues. Heme and oxyferryl have been shown to have a proinflammatory effect further increasing their potential for oxidative stress. These oxidative reactions contribute to a number of pathological situations including atherosclerosis, kidney malfunction, sickle cell disease and malaria. The toxic effects of extracellular Hb are of particular concern for increased hemolysis due to hemolytic anemia. Hemolysis is further exacerbated in various diseases and their treatments. Blood transfusions are required whenever there is an appreciable decrease in RBCs due to hemolysis or blood loss. It is, therefore, essential that transfused blood, whether stored RBCs or blood obtained by an Autologous Blood Recovery System from the patient, does not further increase extracellular Hb.

  7. Evaluation of flow accelerated corrosion by coupled analysis of corrosion and flow dynamics. Relationship of oxide film thickness, hematite/magnetite ratio, ECP and wall thinning rate

    International Nuclear Information System (INIS)

    Uchida, Shunsuke; Naitoh, Masanori; Okada, Hidetoshi; Uehara, Yasushi; Koshizuka, Seiichi

    2011-01-01

    Systematic approaches to evaluate flow accelerated corrosion (FAC) are desired before discussing application of countermeasures for FAC. First, future FAC occurrence should be evaluated to identify locations where a higher possibility of FAC occurrence exists, and then, wall thinning rate at the identified FAC occurrence zone is evaluated to obtain the preparation time for applying countermeasures. Wall thinning rates were calculated with two coupled models: 1.static electrochemical analysis and 2.dynamic oxide layer growth analysis. The anodic current density and the electrochemical corrosion potential (ECP) were calculated with the static electrochemistry model based on an Evans diagram. The ferrous ion release rate, determined by the anodic current density, was applied as input for the dynamic double oxide layer model. Some of the dissolved ferrous ion was removed to the bulk water and others precipitated on the surface as magnetite particles. The thickness of oxide layer was calculated with the dynamic oxide layer growth model and then its value was used as input in the electrochemistry model. It was confirmed that the calculated results (corrosion rate and ECP) based on the coupled models were in good agreement with the measured ones. Higher ECP was essential for preventing FAC rate. Moderated conditions due to lower mass transfer coefficients resulted in thicker oxide layer thickness and then higher ECP, while moderated corrosion conditions due to higher oxidant concentrations resulted in larger hematite/magnetite rate and then higher ECP.

  8. Evaluation of flow accelerated corrosion by coupled analysis of corrosion and flow dynamics (3), relationship of oxide film thickness, hematite/magnetite ratio, ECP and wall thinning rate

    International Nuclear Information System (INIS)

    Uchida, Shunsuke; Naitoh, Masanori; Okada, Hidetoshi; Uehara, Yasushi; Koshizuka, Seiichi

    2009-01-01

    Systematic approaches for evaluating flow accelerated corrosion (FAC) are desired before discussing application of countermeasures for FAC. Firstly, future FAC occurrence should be evaluated to identify locations where a higher possibility of FAC occurrence exists, and then, wall thinning rate at the identified FAC occurrence zone is evaluated to obtain the preparation time for applying countermeasures. Wall thinning rates were calculated with the coupled models of static electrochemical analysis and dynamic double oxide layer analysis. Anodic current density and electrochemical corrosion potential (ECP) were calculated with the static electrochemistry model based on an Evans diagram and ferrous ion release rate determined by the anodic current density was applied as input for the dynamic double oxide layer model. Some of the dissolved ferrous ion was removed to the bulk water and others precipitated on the surface as magnetite particles. The thickness of oxide layer was calculated with the dynamic double oxide layer model and then was applied as input for the electrochemistry model. It was confirmed that the calculated results based on the coupled models resulted good agreement with the measured ones. Higher ECP was essential for preventing FAC rate. Moderated conditions due to lower mass transfer coefficients resulted in thicker oxide layer thickness and then higher ECP, while moderated corrosion conditions due to higher oxidant concentrations resulted in larger hematite/magnetite rate and then higher ECP. (author)

  9. Oxide ceramics

    International Nuclear Information System (INIS)

    Ryshkewitch, E.; Richerson, D.W.

    1985-01-01

    The book explores single-phase ceramic oxide systems from the standpoint of physical chemistry and technology. This second edition also focuses on advances in technology since publication of the original edition. These include improvements in raw materials and forming and sintering techniques, and the major role that oxide ceramics have had in development of advanced products and processes. The text is divided into five major sections: general fundamentals of oxide ceramics, advances in aluminum oxide technology, advances in zirconia technology, and advances in beryllium oxide technology

  10. Electron uptake by iron-oxidizing phototrophic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Bose, A; Gardel, EJ; Vidoudez, C; Parra, EA; Girguis, PR

    2014-02-26

    Oxidation-reduction reactions underlie energy generation in nearly all life forms. Although most organisms use soluble oxidants and reductants, some microbes can access solid-phase materials as electron-acceptors or -donors via extracellular electron transfer. Many studies have focused on the reduction of solid-phase oxidants. Far less is known about electron uptake via microbial extracellular electron transfer, and almost nothing is known about the associated mechanisms. Here we show that the iron-oxidizing photoautotroph Rhodopseudomonas palustris TIE-1 accepts electrons from a poised electrode, with carbon dioxide as the sole carbon source/electron acceptor. Both electron uptake and ruBisCo form I expression are stimulated by light. Electron uptake also occurs in the dark, uncoupled from photosynthesis. Notably, the pioABC operon, which encodes a protein system essential for photoautotrophic growth by ferrous iron oxidation, influences electron uptake. These data reveal a previously unknown metabolic versatility of photoferrotrophs to use extracellular electron transfer for electron uptake.

  11. Biodegradation and corrosion behavior of manganese oxidizer Bacillus cereus ACE4 in diesel transporting pipeline

    International Nuclear Information System (INIS)

    Rajasekar, A.; Ganesh Babu, T.; Karutha Pandian, S.; Maruthamuthu, S.; Palaniswamy, N.; Rajendran, A.

    2007-01-01

    The degradation problem of petroleum products arises since hydrocarbon acts as an excellent food source for a wide variety of microorganisms. Microbial activity leads to unacceptable level of turbidity, corrosion of pipeline and souring of stored product. The present study emphasizes the role of Bacillus cereus ACE4 on degradation of diesel and its influence on corrosion of API 5LX steel. A demonstrating bacterial strain ACE4 was isolated from corrosion products and 16S rRNA gene sequence analysis showed that it has more than 99% similarity with B. cereus. The biodegradation and corrosion studies revealed that B. cereus degraded the aliphatic protons and aromatic protons in diesel and is capable of oxidizing ferrous/manganese into oxides. This is the first report that discloses the involvement of manganese oxidizer B. cereus ACE4 on biodegradation of diesel and its influence on corrosion in a tropical country pipeline

  12. A new cytoplasmic monoheme cytochrome c from Acidithiobacillus ferrooxidans involved in sulfur oxidation.

    Science.gov (United States)

    Liu, Yuandong; Guo, Shuhui; Yu, Runlan; Zou, Kai; Qiu, Guanzhou

    2014-03-01

    Acidithiobacillus ferrooxidans can obtain energy from the oxidation of various reduced inorganic sulfur compounds (RISCs, e.g., sulfur) and ferrous iron in bioleaching so has multiple branched respiratory pathways with a diverse range of electron transporters, especially cytochrome c proteins. A cytochrome c family gene, afe1130, which has never been reported before, was found by screening the whole genome of A. ferrooxidans. Here we report the differential gene transcription, bioinformatics analysis, and molecular modeling of the protein encoded by the afe1130 gene (AFE1130). The differential transcription of the target afe1130 gene versus the reference rrs gene in the A. ferrooxidans, respectively, on the culture conditions of sulfur and ferrous energy sources was performed through quantitative reverse transcription polymerase chain reaction (qRT-PCR) with a SYBR green-based assay according to the standard curves method. The qRT-PCR results showed that the afe1130 gene in sulfur culture condition was obviously more transcribed than that in ferrous culture condition. Bioinformatics analysis indicated that the AFE1130 was affiliated to the subclass ID of class I of cytochrome c and located in cytoplasm. Molecular modeling results exhibited that the AFE1130 protein consisted of 5 alpha-helices harboring one heme c group covalently bonded by Cys13 and Cys16 and ligated by His17 and Met62 and owned a big raised hydrophobic surface responsible for attaching to inner cytomembrane. So the AFE1130 in A. ferrooxidans plays a role in the RISCs oxidation in bioleaching in cytoplasm bound to inner membrane.

  13. Heme oxygenase-1, oxidation, inflammation and atherosclerosis

    Directory of Open Access Journals (Sweden)

    Jesus A Araujo

    2012-07-01

    Full Text Available Atherosclerosis is an inflammatory process of the vascular wall characterized by the infiltration of lipids and inflammatory cells. Oxidative modifications of infiltrating low density lipoproteins and induction of oxidative stress play a major role in lipid retention in the vascular wall, uptake by macrophages and generation of foam cells, a hallmark of this disorder. The vasculature has a plethora of protective resources against oxidation and inflammation, many of them regulated by the Nrf2 transcription factor. Heme oxygenase-1 (HO-1 is a Nrf2-regulated gene that plays a critical role in the prevention of vascular inflammation. It is the inducible isoform of heme oxygenase, responsible for the oxidative cleavage of heme groups leading to the generation of biliverdin, carbon monoxide and release of ferrous iron. HO-1 has important antioxidant, antiinflammatory, antiapoptotic, antiproliferative and immunomodulatory effects in vascular cells, most of which play a significant role in the protection against atherogenesis. HO-1 may also be an important feature in macrophage differentiation and polarization to certain subtypes. The biological effects of HO-1 are largely attributable to its enzymatic activity, which can be conceived as a system with three arms of action, corresponding to its three enzymatic byproducts. HO-1 mediated vascular protection may be due to a combination of systemic and vascular local effects. It is usually expressed at low levels but can be highly upregulated in the presence of several proatherogenic stimuli. The HO-1 system is amenable for use in the development of new therapies, some of them currently under experimental and clinical trials. Interestingly, in contrast to the HO-1 antiatherogenic actions, the expression of its transcriptional regulator Nrf2 leads to proatherogenic effects instead. This article reviews the evidence that supports the antiatherogenic role of HO-1, potential pathways and mechanisms mediating

  14. RNA oxidation

    DEFF Research Database (Denmark)

    Kjaer, L. K.; Cejvanovic, V.; Henriken, T.

    2015-01-01

    RNA modification has attracted increasing interest as it is realized that epitranscriptomics is important in disease development. In type 2 diabetes we have suggested that high urinary excretion of 8-oxo-2'-Guanosine (8oxoGuo), as a measure of global RNA oxidation, is associated with poor survival.......9 significant hazard ratio for death compared with the quartile with the lowest 8oxoGuo excretion when adjusted for age, sex, BMI, smoker status, s-HbA1c, urine protein excretion and s-cholesterol. We conclude that it is now established that RNA oxidation is an independent risk factor for death in type 2...... diabetes. In agreement with our previous finding, DNA oxidation did not show any prognostic value. RNA oxidation represents oxidative stress intracellularly, presumably predominantly in the cytosol. The mechanism of RNA oxidation is not clear, but hypothesized to result from mitochondrial dysfunction...

  15. Consumption of galacto-oligosaccharides increases iron absorption from a micronutrient powder containing ferrous fumarate and sodium iron EDTA: a stable-isotope study in Kenyan infants.

    Science.gov (United States)

    Paganini, Daniela; Uyoga, Mary A; Cercamondi, Colin I; Moretti, Diego; Mwasi, Edith; Schwab, Clarissa; Bechtler, Salome; Mutuku, Francis M; Galetti, Valeria; Lacroix, Christophe; Karanja, Simon; Zimmermann, Michael B

    2017-10-01

    Background: Whether consumption of prebiotics increases iron absorption in infants is unclear. Objective: We set out to determine whether prebiotic consumption affects iron absorption from a micronutrient powder (MNP) containing a mixture of ferrous fumarate and sodium iron EDTA (FeFum+NaFeEDTA) in Kenyan infants. Design: Infants ( n = 50; aged 6-14 mo) consumed maize porridge that was fortified with an MNP containing FeFum+NaFeEDTA and 7.5 g galacto-oligosaccharides (GOSs) (Fe+GOS group, n = 22) or the same MNP without GOSs (Fe group, n = 28) each day for 3 wk. Then, on 2 consecutive days, we fed all infants isotopically labeled maize porridge and MNP test meals containing 5 mg Fe as 57 FeFum+Na 58 FeEDTA or ferrous sulfate ( 54 FeSO 4 ). Iron absorption was measured as the erythrocyte incorporation of stable isotopes. Iron markers, fecal pH, and bacterial groups were assessed at baseline and 3 wk. Comparisons within and between groups were done with the use of mixed-effects models. Results: There was a significant group-by-compound interaction on iron absorption ( P = 0.011). The median percentages of fractional iron absorption from FeFum+NaFeEDTA and from FeSO 4 in the Fe group were 11.6% (IQR: 6.9-19.9%) and 20.3% (IQR: 14.2-25.7%), respectively, ( P iron absorption was greater from the FeFum+NaFeEDTA ( P = 0.047) in the Fe+GOS group but not from the FeSO 4 ( P = 0.653). The relative iron bioavailability from FeFum+NaFeEDTA compared with FeSO 4 was higher in the Fe+GOS group than in the Fe group (88% compared with 63%; P = 0.006). There was a significant time-by-group interaction on Bifidobacterium spp. ( P = 0.008) and Lactobacillus / Pediococcus / Leuconostoc spp. ( P = 0.018); Lactobacillus / Pediococcus / Leuconostoc spp. decreased in the Fe group ( P = 0.013), and there was a nonsignificant trend toward higher Bifidobacterium spp. in the Fe+GOS group ( P = 0.099). At 3 wk, iron absorption was negatively correlated with fecal pH ( P iron absorption by 62

  16. Bacterial Oxidation and Reduction of Iron in the Processes of Creation and Treatment of Acid Mining Waters

    Directory of Open Access Journals (Sweden)

    Daniel Kupka

    2004-12-01

    Full Text Available Acid mine drainages (AMDs arise at the weathering of sulphidic minerals. The occurrence of acidic streams is commonly associated with the human mining activities. Due to the disruption and excavation of sulphide deposits, the oxidation processes have initiated. Acidic products of sulphide oxidation accelerate the degradation of accompanying minerals. AMDs typically contain high concentrations of sulfuric acid and soluble metals and cause serious ecological problems due to the water pollution and the devastation of adjacent country. Microbial life in these extremely acidic environments may be considerably diverse. AMDs are abundant in bacteria capable to oxidize and/or to reduce iron. The rate of bacterial oxidation of ferrous iron released from pyrite surfaces is up to one million times faster than the chemical oxidation rate at low pH. Bacterial regeneration of ferric iron maintains the continuity of pyrite oxidation and the production of AMDs. Another group of microorganisms living in these environments are acidophilic ferric iron reducing bacteria. This group of microorganisms has been discovered only relatively recently. Acidophilic heterotrophic bacteria reduce ferric iron in either soluble or solid forms to ferrous iron. The reductive dissolution of ferric iron minerals brings about a mobilization of iron as well as associated heavy metals. The Bacterial oxidation and reduction of iron play an important role in the transformation of either crystalline or amorphous iron-containing minerals, including sulphides, oxides, hydroxysulfates, carbonates and silicates. This work discusses the role of acidophilic bacteria in the natural iron cycling and the genesis of acidic effluents. The possibilities of application of iron bacteria in the remediation of AMDs are also considered.

  17. Aqueous photocatalytic oxidation of lignin and humic acids with supported TiO2

    Directory of Open Access Journals (Sweden)

    Elina Portjanskaja

    2006-01-01

    Full Text Available The photocatalytic oxidation (PCO of UV-irradiated aqueous solutions containing humic acids and lignin was studied. The photocatalyst TiO2 was attached to buoyant hollow glass microspheres and glass plates. A maximum oxidation efficiency as low as 1.1 and 2.54 mg W−1h−1 for humic acids and lignin, respectively, was achieved in neutral and alkaline media with 25 gm−2 of the buoyant catalyst. In acidic media, efficiency was even lower. The photocatalytic efficiency with the photocatalyst attached to glass plates was about 3 to 4 times higher than that for the buoyant catalyst. Ferrous ions added to acidic solutions did not increase the rate of PCO of humic acids. However the addition of Fe2+ ions, up to 0.05 mM, to the lignin solution leads to a dramatic increase, about 25%, in PCO efficiency. A further increase in ferrous ion concentration results in a decrease in the PCO efficiency of lignin. Proceeding most likely by a radical mechanism, the efficiency of PCO of humic acids did not benefit from an excessive presence of hydroxyl radical promoters, such as hydrogen peroxide, although the reaction rate increased. However, PCO of lignin in the acidic medium, where OH.-radical formation is suppressed, benefited from the introduction of hydrogen peroxide due to promoted radical formation.

  18. Aqueous photocatalytic oxidation of lignin and humic acids with supported TiO 2

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available The photocatalytic oxidation (PCO of UV-irradiated aqueous solutions containing humic acids and lignin was studied. The photocatalyst TiO 2 was attached to buoyant hollow glass microspheres and glass plates. A maximum oxidation efficiency as low as 1.1 and 2.54 mg W −1 h −1 for humic acids and lignin, respectively, was achieved in neutral and alkaline media with 25 gm −2 of the buoyant catalyst. In acidic media, efficiency was even lower. The photocatalytic efficiency with the photocatalyst attached to glass plates was about 3 to 4 times higher than that for the buoyant catalyst. Ferrous ions added to acidic solutions did not increase the rate of PCO of humic acids. However the addition of Fe 2+ ions, up to 0.05 mM, to the lignin solution leads to a dramatic increase, about 25%, in PCO efficiency. A further increase in ferrous ion concentration results in a decrease in the PCO efficiency of lignin. Proceeding most likely by a radical mechanism, the efficiency of PCO of humic acids did not benefit from an excessive presence of hydroxyl radical promoters, such as hydrogen peroxide, although the reaction rate increased. However, PCO of lignin in the acidic medium, where OH.-radical formation is suppressed, benefited from the introduction of hydrogen peroxide due to promoted radical formation.

  19. Graphene oxide/ferric hydroxide composites for efficient arsenate removal from drinking water

    International Nuclear Information System (INIS)

    Zhang Kai; Dwivedi, Vineet; Chi Chunyan; Wu Jishan

    2010-01-01

    A series of novel composites based on graphene oxide (GO) cross-linked with ferric hydroxide was developed for effective removal of arsenate from contaminated drinking water. GO, which was used as a supporting matrix here, was firstly treated with ferrous sulfate. Then, the ferrous compound cross-linked with GO was in situ oxidized to ferric compound by hydrogen peroxide, followed by treating with ammonium hydroxide. The morphology and composition of the composites were analyzed by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The ferric hydroxide was found to be homogenously impregnated onto GO sheets in amorphous form. These composites were evaluated as absorbents for arsenate removal from contaminated drinking water. For the water with arsenate concentration at 51.14 ppm, more than 95% of arsenate was absorbed by composite GO-Fe-5 with an absorption capacity of 23.78 mg arsenate/g of composite. Effective arsenate removal occurred in a wide range of pH from 4 to 9. However, the efficiency of arsenate removal was decreased when pH was increased to higher than 8.

  20. Sphaerotilus natans encrusted with nanoball-shaped Fe(III) oxide minerals formed by nitrate-reducing mixotrophic Fe(II) oxidation

    Science.gov (United States)

    Park, Sunhwa; Kim, Dong-Hun; Lee, Ji-Hoon; Hur, Hor-Gil

    2014-01-01

    Ferrous iron has been known to function as an electron source for iron-oxidizing microorganisms in both anoxic and oxic environments. A diversity of bacteria has been known to oxidize both soluble and solid-phase Fe(II) forms coupled to the reduction of nitrate. Here, we show for the first time Fe(II) oxidation by Sphaerotilus natans strain DSM 6575T under mixotrophic condition. Sphaerotilus natans has been known to form a sheath structure enclosing long chains of rod-shaped cells, resulting in a thick biofilm formation under oxic conditions. Here, we also demonstrate that strain DSM 6575T grows mixotrophically with pyruvate, Fe(II) as electron donors and nitrate as an electron acceptor and single cells of strain DSM 6575T are dominant under anoxic conditions. Furthermore, strain DSM 6575T forms nanoball-shaped amorphous Fe(III) oxide minerals encrusting on the cell surfaces through the mixotrophic iron oxidation reaction under anoxic conditions. We propose that cell encrustation results from the indirect Fe(II) oxidation by biogenic nitrite during nitrate reduction and that causes the bacterial morphological change to individual rod-shaped single cells from filamentous sheath structures. This study extends the group of existing microorganisms capable of mixotrophic Fe(II) oxidation by a new strain, S. natans strain DSM 6575T, and could contribute to biogeochemical cycles of Fe and N in the environment. PMID:24965827

  1. Effects of thermal treatment on mineralogy and heavy metal behavior in iron oxide stabilized air pollution control residues

    DEFF Research Database (Denmark)

    Sørensen, Mette Abildgaard; Bender-Koch, C.; Starckpoole, M. M.

    2000-01-01

    Stabilization of air pollution control residues by coprecipitation with ferrous iron and subsequent thermal treatment (at 600 and 900 °C) has been examined as a means to reduce heavy metal leaching and to improve product stability. Changes in mineralogy and metal binding were analyzed using various...... volatilized or destabilized with respect to leaching. Pb, in particular, exhibited increased reactivity following the formation of an ordered iron oxide structure at 900 °C. The thermal treatment had a positive effect on Cr release, which was reduced significantly at 900 °C in the presence of organic matter...

  2. Photo- and chemocatalytic oxidation of dyes in water.

    Science.gov (United States)

    Du, Wei-Ning; Chen, Shyi-Tien

    2018-01-15

    Three commonly used dyes, Acid Red-114 (AR-114), Reactive Black-5 (RB-5), and Disperse Black EX-SF (DB-EX-SF), were treated in a pH-neutral liquid with ultraviolet (UV) light by two reactive methods: photocatalysis with titanium dioxide (TiO 2 ), and/or chemocatalysis with hydrogen peroxide (H 2 O 2 ) as the oxidant and various ferrous-based electron mediators as catalysts. Important factors for dye oxidation were determined through bifactorial experiments. The optimum combinations and doses of the three key reagents, namely TiO 2 , H 2 O 2 , and EDTA-Fe, were also determined. The degradation kinetics of the studied dyes at their optimum doses reveal that the oxidation reactions are pseudo-first-order in nature, and that certain dyes are selectively degraded more by one method than the other. The overall results suggest that co-treatment using more than one oxidative method is beneficial for the treatment of wastewater from dyeing processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Iron oxide nanoparticles for magnetically assisted patterned coatings

    Energy Technology Data Exchange (ETDEWEB)

    Dodi, Gianina; Hritcu, Doina, E-mail: dhritcu@ch.tuiasi.ro; Draganescu, Dan; Popa, Marcel I.

    2015-08-15

    Iron oxide nanoparticles able to magnetically assemble during the curing stage of a polymeric support to create micro-scale surface protuberances in a controlled manner were prepared and characterized. The bare Fe{sub 3}O{sub 4} particles were obtained by two methods: co-precipitation from an aqueous solution containing Fe{sup 3+}/Fe{sup 2+} ions with a molar ratio of 2:1 and partial oxidation of ferrous ions in alkaline conditions. The products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and magnetization measurement. They were subsequently functionalized using oleic acid, sodium oleate, or non-ionic surfactant mixtures with various hydrophilic to lipophilic balance (HLB) values. Composite nanoparticle-polymer films prepared by spraying were deposited and cured by drying on glass slides under a static magnetic field in the range of 1.5–5.5 mT. Magnetic field generated surface roughness was evidenced by optical and scanning electron microscopy. The optimum hierarchical patterning was obtained with the nanoparticles produced by partial oxidation and functionalized with hydrophobic surfactants. Possible applications may include ice-phobic composite coatings. - Highlights: • Magnetite nanoparticles bearing variable hydrophobic functionality were synthesized. • Partial oxidation in alkaline solution is proved to be the optimum synthesis method. • Nanoparticle assembly in magnetic field produced films with hierarchical roughness. • Coating patterning is controlled by surfactant nature and magnetic field strength. • Possible applications in composite films with ice-phobic properties are suggested.

  4. Structure of Stenotrophomonas maltophilia FeoA complexed with zinc: a unique prokaryotic SH3-domain protein that possibly acts as a bacterial ferrous iron-transport activating factor

    International Nuclear Information System (INIS)

    Su, Yi-Che; Chin, Ko-Hsin; Hung, Hui-Chih; Shen, Gwan-Han; Wang, Andrew H.-J.; Chou, Shan-Ho

    2010-01-01

    The crystal structure of FeoA from Stenotrophomonas maltophilia has been determined to a resolution of 1.7 Å using an Se single-wavelength anomalous dispersion (Se-SAD) approach and revealed a unique dimer cross-linked by two zinc ions and six chloride ions. Iron is vital to the majority of prokaryotes, with ferrous iron believed to be the preferred form for iron uptake owing to its much better solubility. The major route for bacterial ferrous iron uptake is found to be via an Feo (ferrous iron-transport) system comprising the three proteins FeoA, FeoB and FeoC. Although the structure and function of FeoB have received much attention recently, the roles played by FeoA and FeoC have been little investigated to date. Here, the tertiary structure of FeoA from Stenotrophomonas maltophilia (Sm), a vital opportunistic pathogen in immunodepressed hosts, is reported. The crystal structure of SmFeoA has been determined to a resolution of 1.7 Å using an Se single-wavelength anomalous dispersion (Se-SAD) approach. Although SmFeoA bears low sequence identity to eukaryotic proteins, its structure is found to adopt a eukaryotic SH3-domain-like fold. It also bears weak similarity to the C-terminal SH3 domain of bacterial DtxR (diphtheria toxin regulator), with some unique characteristics. Intriguingly, SmFeoA is found to adopt a unique dimer cross-linked by two zinc ions and six anions (chloride ions). Since FeoB has been found to contain a G-protein-like domain with low GTPase activity, FeoA may interact with FeoB through the SH3–G-protein domain interaction to act as a ferrous iron-transport activating factor

  5. High-spin ferric ions in Saccharomyces cerevisiae vacuoles are reduced to the ferrous state during adenine-precursor detoxification.

    Science.gov (United States)

    Park, Jinkyu; McCormick, Sean P; Cockrell, Allison L; Chakrabarti, Mrinmoy; Lindahl, Paul A

    2014-06-24

    The majority of Fe in Fe-replete yeast cells is located in vacuoles. These acidic organelles store Fe for use under Fe-deficient conditions and they sequester it from other parts of the cell to avoid Fe-associated toxicity. Vacuolar Fe is predominantly in the form of one or more magnetically isolated nonheme high-spin (NHHS) Fe(III) complexes with polyphosphate-related ligands. Some Fe(III) oxyhydroxide nanoparticles may also be present in these organelles, perhaps in equilibrium with the NHHS Fe(III). Little is known regarding the chemical properties of vacuolar Fe. When grown on adenine-deficient medium (A↓), ADE2Δ strains of yeast such as W303 produce a toxic intermediate in the adenine biosynthetic pathway. This intermediate is conjugated with glutathione and shuttled into the vacuole for detoxification. The iron content of A↓ W303 cells was determined by Mössbauer and EPR spectroscopies. As they transitioned from exponential growth to stationary state, A↓ cells (supplemented with 40 μM Fe(III) citrate) accumulated two major NHHS Fe(II) species as the vacuolar NHHS Fe(III) species declined. This is evidence that vacuoles in A↓ cells are more reducing than those in adenine-sufficient cells. A↓ cells suffered less oxidative stress despite the abundance of NHHS Fe(II) complexes; such species typically promote Fenton chemistry. Most Fe in cells grown for 5 days with extra yeast-nitrogen-base, amino acids and bases in minimal medium was HS Fe(III) with insignificant amounts of nanoparticles. The vacuoles of these cells might be more acidic than normal and can accommodate high concentrations of HS Fe(III) species. Glucose levels and rapamycin (affecting the TOR system) affected cellular Fe content. This study illustrates the sensitivity of cellular Fe to changes in metabolism, redox state and pH. Such effects broaden our understanding of how Fe and overall cellular metabolism are integrated.

  6. Assessment of predictive models for the failure of titanium and ferrous alloys due to hydrogen effects. Report for the period of June 16 to September 15, 1981

    International Nuclear Information System (INIS)

    Archbold, T.F.; Bower, R.B.; Polonis, D.H.

    1982-04-01

    The 1977 version of the Simpson-Puls-Dutton model appears to be the most amenable with respect to utilizing known or readily estimated quantities. The Pardee-Paton model requires extensive calculations involving estimated quantities. Recent observations by Koike and Suzuki on vanadium support the general assumption that crack growth in hydride forming metals is determined by the rate of hydride formation, and their hydrogen atmosphere-displacive transformation model is of potential interest in explaining hydrogen embrittlement in ferrous alloys as well as hydride formers. The discontinuous nature of cracking due to hydrogen embrittlement appears to depend very strongly on localized stress intensities, thereby pointing to the role of microstructure in influencing crack initiation, fracture mode and crack path. The initiation of hydrogen induced failures over relatively short periods of time can be characterized with fair reliability using measurements of the threshold stress intensity. The experimental conditions for determining K/sub Th/ and ΔK/sub Th/ are designed to ensure plane strain conditions in most cases. Plane strain test conditions may be viewed as a conservative basis for predicting delayed failure. The physical configuration of nuclear waste canisters may involve elastic/plastic conditions rather than a state of plane strain, especially with thin-walled vessels. Under these conditions, alternative predictive tests may be considered, including COD and R-curve methods. The double cantilever beam technique employed by Boyer and Spurr on titanium alloys offers advantages for examining hydrogen induced delayed failure over long periods of time. 88 references

  7. The Safety and Tolerability of 5-Aminolevulinic Acid Phosphate with Sodium Ferrous Citrate in Patients with Type 2 Diabetes Mellitus in Bahrain

    Directory of Open Access Journals (Sweden)

    Feryal Al-Saber

    2016-01-01

    Full Text Available Type 2 diabetes mellitus is prevalent especially in Gulf countries and poses serious long-term risks to patients. A multifaceted treatment approach can include nutritional supplements with antioxidant properties such as 5-aminolevulinic acid (5-ALA with sodium ferrous citrate (SFC. This prospective, randomized, single-blind, placebo-controlled, dose escalating pilot clinical trial assessed the safety of 5-ALA with SFC at doses up to 200 mg 5-ALA/229.42 mg SFC per day in patients living in Bahrain with type 2 diabetes mellitus that was uncontrolled despite the use of one or more antidiabetic drugs. Fifty-three patients (n=53 from 3 sites at one center were enrolled by Dr. Feryal (Site #01, Dr. Hesham (Site #02, and Dr. Waleed (Site #03 (n=35, 5-ALA-SFC; n=18, placebo. There was no significant difference in incidence of adverse events reported, and the most frequent events reported were gastrointestinal in nature, consistent with the known safety profile of 5-ALA in patients with diabetes. No significant changes in laboratory values and no difference in hypoglycemia between patients receiving 5-ALA and placebo were noted. Overall, the current results support that use of 5-ALA-SFC up to 200 mg per day taken as 2 divided doses is safe in patients taking concomitant oral antidiabetic medications and may offer benefits in the diabetic population. This trial is registered with ClinicalTrials.gov NCT02481141.

  8. Effect of excess dietary iron as ferrous sulfate and excess dietary ascorbic acid on liver zinc, copper and sulfhydryl groups and the ovary

    International Nuclear Information System (INIS)

    Edwards, C.H.; Adkins, J.S.; Harrison, B.

    1986-01-01

    Female guinea pigs of the NIH 13/N strain, weighing between 475 and 512 g, were fed diets supplemented with 50 to 2500 mg of iron per kg of diet as ferrous sulfate and 0.2 to 8.0 g of ascorbic acid per kg of diet. A significant effect was observed on tissue copper and zinc, ovary weight and liver protein sulfhydryl groups. The mean ovary weight for guinea pigs fed 2500 mg of iron was significantly less than that of animals fed 50 mg of iron, 0.045 +/- 0.012 g and 0.061 +/- 0.009 g, respectively. Liver zinc content of animals fed 2500 mg of iron and 200 mg of ascorbic acid per kg of diet was significantly less than that of animals fed 50 mg of iron and 200 mg of ascorbic acid, 16.3 +/- 3.3 μg and 19.6 +/- 1.6 μg, respectively. There was no difference in liver copper due to dietary iron, but when dietary ascorbic acid was increased to 8 g per kg of diet, there was a significant decrease (from 22.8 +/- 8.1 μg to 10.5 +/- 4.8 μg) in liver copper. Excess dietary ascorbic acid decreased ovarian zinc significantly when increased to 8 g per kg of diet, 2929 +/- 919 μg vs 1661 +/- 471 μg, respectively, when compared to the control group

  9. Clarification and filtration of the floculated partuicles suspension from a chemical treatment of waste oil-in-water emulsions from a non-ferrous metalworking plant

    Directory of Open Access Journals (Sweden)

    Lazarević Vesna B.

    2011-01-01

    Full Text Available The effects of the coagulation/floculation conditions on clarification and filtration of the floculated particle suspension obtained by the chemical treatment of the waste oil-in-water emulsion (OWE from a non-ferrous metalworking plant were studied. The treatment involved the addition of aluminum(III sulfate and lime to the OWE. The main goal was to define the optimum conditions for clarification and filtration of the floculated particle suspension. The factors involved were amounts lime (i.e. pH and filter aid added the OWE on clarification and filtration rates. At pH>10, the clarification rate was increased and the final volume of the concentrated suspension (sludge was reduced, while filter aid affected negatively the clarification rate. The filtration rate was also increased when the coagulation was carried out at pH>10. The floculated particle suspension should be concentrated before filtration in order to decrease the filtration duration. The most efficient filter aid was Celite standard super-cel, its optimum initial concentration being found to be 2 g/dm3.

  10. Characterisation and treatment of roads covered with zinc ashes, muffle furnace fragments and lead slags from former non-ferrous metal industries in Belgium.

    Science.gov (United States)

    Vandecasteele, C; Van den Broeck, K; Van Gerven, T; Dutré, V; Seuntjens, P; Berghmans, P; Cornelis, C; Nouwen, J

    2002-08-01

    Zinc ashes, muffle furnace fragments and lead slags from non-ferrous industries were applied to pave roads in the North of Belgium. From an inventory it appeared that there are at least 490 km of such roads. In our survey the materials on these roads were characterised. The total metal concentration, the availability and the leaching as a function of time were determined. It appeared that these materials contain high concentrations of heavy metals, some of which are readily available. The high leaching of some metals makes them as such unsuitable as secondary construction material. Methods for the application of these materials for road construction were examined where the materials replaced part of the sand and gravel fraction in lean concrete and in bituminous mixtures, or where they replaced the sand in sand-cement mixtures, all these to be used for road foundations, cycle tracks, etc. When lead slags were applied in lean concrete, a material was obtained complying with the standards for secondary construction materials and with sufficient compressive strength for road foundations. When zinc ashes or muffle fragments were used to replace sand in sand-cement mixtures, again a suitable construction material was obtained. The other combinations tried out were rather unsuccessful, because of high metal leaching and/or poor compressive strength.

  11. Coverage and adequacy of ferrous sulfate supplementation in the prevention of anemia among children treated at health centers of Florianopolis, Santa Catarina

    Directory of Open Access Journals (Sweden)

    Francieli Cembranel

    2013-09-01

    Full Text Available OBJECTIVE To evaluate the National Program of Iron Supplementation (PNSF coverage, the compliance with the directions for of using of this supplementation and the association with sociodemographic factors in children aged six to 18 months old and registered in 35 public health centers of Florinópolis (Southern Brazil. METHODS Cross-sectional study using secondary data obtained from the health information system of the Health Department of Florianópolis, Santa Catarina, Brazil (Infosaúde. Data on ferrous sulfate supplementation and sociodemographic variables were obtained of all children registered in PNSF in Florianópolis in 2010. STATA 11.0 software was used in the analyses. RESULTS The PNSF covered 6.3% (95%CI 5.9-6.7 of the children; the compliance with the directions regarding age at the onset of supplementation and its frequency was adequate only in 2.4% of the cases (95%CI 1.5-3.7. There was no association with the child's gender, maternal education level and ethnicity or the distance from home to the health center. CONCLUSIONS This study showed low coverage and inadequate compliance with the PNSF directions. Measures to improve this strategy are urgent.

  12. Scaling up the chemical treatment of spent oil-in-water emulsions from a non-ferrous metal-processing plant

    Directory of Open Access Journals (Sweden)

    Lazarević Vesna B.

    2013-01-01

    Full Text Available The treatment of spent oil-in-water emulsion (SOWE from a non-ferrous metal-processing plant by using aluminum sulfate and hydrated lime was studied to determine the purification efficiency, to optimize the operating conditions and to scale up the treatment process. The purification efficiency was estimated by comparing the compositions of the SOWE and the processed wastewater. The treatment efficiency does not depend on the type of mineral oil and filter aid. The optimum doses of aluminum sulfate and hydrated lime must be experimentally determined for each batch of SOWEs, but the results obtained at laboratory level are applicable at pilot level. The processed wastewater and the filter cake from the process can be safely disposed into public sewage systems and at municipal waste landfills, respectively. The purification efficiency was higher than 98% with respect to total suspended solids, chemical oxygen demand and oil and grease, and was comparable to the known treatment processes based on coagulation/flocculation followed by sedimentation.

  13. Selective oxidation

    International Nuclear Information System (INIS)

    Cortes Henao, Luis F.; Castro F, Carlos A.

    2000-01-01

    It is presented a revision and discussion about the characteristics and factors that relate activity and selectivity in the catalytic and not catalytic partial oxidation of methane and the effect of variables as the temperature, pressure and others in the methane conversion to methanol. It thinks about the zeolites use modified for the catalytic oxidation of natural gas

  14. Introducing a 2-His-1-Glu Nonheme Iron Center into Myoglobin Confers Nitric Oxide Reductase Activity

    Energy Technology Data Exchange (ETDEWEB)

    Y Lin; N Yeung; Y Gao; K Miner; L Lei; H Robinson; Y Lu

    2011-12-31

    A conserved 2-His-1-Glu metal center, as found in natural nonheme iron-containing enzymes, was engineered into sperm whale myoglobin by replacing Leu29 and Phe43 with Glu and His, respectively (swMb L29E, F43H, H64, called Fe{sub B}Mb(-His)). A high resolution (1.65 {angstrom}) crystal structure of Cu(II)-CN{sup -}-Fe{sub B}Mb(-His) was determined, demonstrating that the unique 2-His-1-Glu metal center was successfully created within swMb. The Fe{sub B}Mb(-His) can bind Cu, Fe, or Zn ions, with both Cu(I)-Fe{sub B}Mb(-His) and Fe(II)-Fe{sub B}Mb(-His) exhibiting nitric oxide reductase (NOR) activities. Cu dependent NOR activity was significantly higher than that of Fe in the same metal binding site. EPR studies showed that the reduction of NO to N{sub 2}O catalyzed by these two enzymes resulted in different intermediates; a five-coordinate heme-NO species was observed for Cu(I)-Fe{sub B}Mb(-His) due to the cleavage of the proximal heme Fe-His bond, while Fe(II)-Fe{sub B}Mb(-His) remained six-coordinate. Therefore, both the metal ligand, Glu29, and the metal itself, Cu or Fe, play crucial roles in NOR activity. This study presents a novel protein model of NOR and provides insights into a newly discovered member of the NOR family, gNOR.

  15. Introducing a 2-His-1-Glu Nonheme Iron Center into Myoglobin Confers Nitric Oxide Reductase Activity

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Y.W.; Robinson, H.; Yeung, N.; Gao, Y.-G.; Miner, K. D.; Lei, L.; Lu, Y.

    2010-07-28

    A conserved 2-His-1-Glu metal center, as found in natural nonheme iron-containing enzymes, was engineered into sperm whale myoglobin by replacing Leu29 and Phe43 with Glu and His, respectively (swMb L29E, F43H, H64, called Fe{sub B}Mb(-His)). A high resolution (1.65 {angstrom}) crystal structure of Cu(II)-CN?-Fe{sub B}Mb(-His) was determined, demonstrating that the unique 2-His-1-Glu metal center was successfully created within swMb. The Fe{sub B}Mb(-His) can bind Cu, Fe, or Zn ions, with both Cu(I)-Fe{sub B}Mb(-His) and Fe(II)-Fe{sub B}Mb(-His) exhibiting nitric oxide reductase (NOR) activities. Cu dependent NOR activity was significantly higher than that of Fe in the same metal binding site. EPR studies showed that the reduction of NO to N{sub 2}O catalyzed by these two enzymes resulted in different intermediates; a five-coordinate heme-NO species was observed for Cu(I)-Fe{sub B}Mb(-His) due to the cleavage of the proximal heme Fe-His bond, while Fe(II)-Fe{sub B}Mb(-His) remained six-coordinate. Therefore, both the metal ligand, Glu29, and the metal itself, Cu or Fe, play crucial roles in NOR activity. This study presents a novel protein model of NOR and provides insights into a newly discovered member of the NOR family, gNOR.

  16. Impacts of operating parameters on oxidation-reduction potential and pretreatment efficacy in the pretreatment of printing and dyeing wastewater by Fenton process

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Huifang, E-mail: whfkhl@sina.com [College of Environment, Jiangsu Key Laboratory of Industrial Water-Conservation and Emission Reduction, Nanjing University of Technology, Nanjing 210009 (China); Wang, Shihe [Department of Municipal Engineering, Southeast University, Nanjing 210096 (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer A real printing and dyeing wastewater was pretreated by Fenton process. Black-Right-Pointing-Pointer We investigated impacts of operating parameters on ORP and pretreatment efficacy. Black-Right-Pointing-Pointer Relationship among ORP, operating parameters and treatment efficacy was established. Black-Right-Pointing-Pointer Pretreatment efficacy was in proportion to the exponent of temperature reciprocal. Black-Right-Pointing-Pointer We investigated kinetics of color and COD removal and BOD{sub 5}/COD ratio in solution. - Abstract: An experiment was conducted in a batch reactor for a real printing and dyeing wastewater pretreatment using Fenton process in this study. The results showed that original pH, hydrogen peroxide concentration and ferrous sulfate concentration affected ORP value and pretreatment efficacy greatly. Under experimental conditions, the optimal original pH was 6.61, and the optimal hydrogen peroxide and ferrous sulfate concentrations were 1.50 and 0.75 g L{sup -1}, respectively. The relationship among ORP, original pH, hydrogen peroxide concentration, ferrous sulfate concentration, and color (COD or BOD{sub 5}/COD) was established, which would be instructive in on-line monitoring and control of Fenton process using ORP. In addition, the effects of wastewater temperature and oxidation time on pretreatment efficacy were also investigated. With an increase of temperature, color and COD removal efficiencies and BOD{sub 5}/COD ratio increased, and they were in proportion to the exponent of temperature reciprocal. Similarly, color and COD removal efficiencies increased with increasing oxidation time, and both color and COD removal obeyed the first-order kinetics. The BOD{sub 5}/COD ratio could be expressed by a second-degree polynomial with respect to oxidation time, and the best biodegradability of wastewater was present at the oxidation time of 6.10 h.

  17. Specimen Validity Testing SVT) - Effects of Oxidizing Agents on Drugs in Urine and Procedures for Detection.

    Science.gov (United States)

    Paul, B D; Dunkley, C S

    2007-07-01

    Since the inception of the drug-testing program in the U.S. Armed Forces in 1982, urine adulteration with the intent to conceal drug use has been a serious problem to forensic scientists. Initially, drug users tried almost anything that was available at the collection sites. Soon they recognized that certain chemicals could be used to destroy some drugs and interfere with the testing procedures. Some drug analytes, in particular morphine and 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid, a metabolite of delta-9-tetrahydrocannabinol, could not be detected in presence of some oxidizing agents. As the use of adulterants increased, specimen validity testing was introduced by the Department of Health and Human Services in 2004. While specific reagents could be used to test nitrite, chromate, and iodine, test procedures for many other oxidizing agents were not available. In an attempt to detect most oxidants, a different approach has been introduced to identify urines adulterated with oxidizing adulterants. In this approach, the oxidizing property of normal urine is compared with that of urine containing oxidizing agents. In the procedure, samples are allowed to interact with excess ferrous (Fe2+) ions and then with chromogenic compounds. In the presence of oxidants, Fe2+ ions with low reduction potential (E0 0.771 V) are immediately oxidized to ferric (Fe3+) ions, which then change the chromogenic compounds to colored chromogens. Specific spectral pattern and intensity are the keys in quantification of oxidants in urine (milliEquivalent/liter, mE/L). The method appeared to be promising in differentiating normal urine from urine adulterated with oxidizing agents. Some oxidizing adulterants in urine are unstable. If reduced, it could be reconverted to the oxidizing agents and tested by the general oxidant test. Copyright © 2007 Central Police University.

  18. Anodic oxidation

    CERN Document Server

    Ross, Sidney D; Rudd, Eric J; Blomquist, Alfred T; Wasserman, Harry H

    2013-01-01

    Anodic Oxidation covers the application of the concept, principles, and methods of electrochemistry to organic reactions. This book is composed of two parts encompassing 12 chapters that consider the mechanism of anodic oxidation. Part I surveys the theory and methods of electrochemistry as applied to organic reactions. These parts also present the mathematical equations to describe the kinetics of electrode reactions using both polarographic and steady-state conditions. Part II examines the anodic oxidation of organic substrates by the functional group initially attacked. This part particular

  19. Anoxic and Oxic Oxidation of Rocks Containing Fe(II)Mg-Silicates and Fe(II)-Monosulfides as Source of Fe(III)-Minerals and Hydrogen. Geobiotropy.

    Science.gov (United States)

    Bassez, Marie-Paule

    2017-12-01

    In this article, anoxic and oxic hydrolyses of rocks containing Fe (II) Mg-silicates and Fe (II)-monosulfides are analyzed at 25 °C and 250-350 °C. A table of the products is drawn. It is shown that magnetite and hydrogen can be produced during low-temperature (25 °C) anoxic hydrolysis/oxidation of ferrous silicates and during high-temperature (250 °C) anoxic hydrolysis/oxidation of ferrous monosulfides. The high-T (350 °C) anoxic hydrolysis of ferrous silicates leads mainly to ferric oxides/hydroxides such as the hydroxide ferric trihydroxide, the oxide hydroxide goethite/lepidocrocite and the oxide hematite, and to Fe(III)-phyllosilicates. Magnetite is not a primary product. While the low-T (25 °C) anoxic hydrolysis of ferrous monosulfides leads to pyrite. Thermodynamic functions are calculated for elementary reactions of hydrolysis and carbonation of olivine and pyroxene and E-pH diagrams are analyzed. It is shown that the hydrolysis of the iron endmember is endothermic and can proceed within the exothermic hydrolysis of the magnesium endmember and also within the exothermic reactions of carbonations. The distinction between three products of the iron hydrolysis, magnetite, goethite and hematite is determined with E-pH diagrams. The hydrolysis/oxidation of the sulfides mackinawite/troilite/pyrrhotite is highly endothermic but can proceed within the heat produced by the exothermic hydrolyses and carbonations of ferromagnesian silicates and also by other sources such as magma, hydrothermal sources, impacts. These theoretical results are confirmed by the products observed in several related laboratory experiments. The case of radiolyzed water is studied. It is shown that magnetite and ferric oxides/hydroxides such as ferric trihydroxide, goethite/lepidocrocite and hematite are formed in oxic hydrolysis of ferromagnesian silicates at 25 °C and 350 °C. Oxic oxidation of ferrous monosulfides at 25 °C leads mainly to pyrite and ferric oxides

  20. Anoxic and Oxic Oxidation of Rocks Containing Fe(II)Mg-Silicates and Fe(II)-Monosulfides as Source of Fe(III)-Minerals and Hydrogen. Geobiotropy.

    Science.gov (United States)

    Bassez, Marie-Paule

    2017-12-01

    In this article, anoxic and oxic hydrolyses of rocks containing Fe (II) Mg-silicates and Fe (II)-monosulfides are analyzed at 25 °C and 250-350 °C. A table of the products is drawn. It is shown that magnetite and hydrogen can be produced during low-temperature (25 °C) anoxic hydrolysis/oxidation of ferrous silicates and during high-temperature (250 °C) anoxic hydrolysis/oxidation of ferrous monosulfides. The high-T (350 °C) anoxic hydrolysis of ferrous silicates leads mainly to ferric oxides/hydroxides such as the hydroxide ferric trihydroxide, the oxide hydroxide goethite/lepidocrocite and the oxide hematite, and to Fe(III)-phyllosilicates. Magnetite is not a primary product. While the low-T (25 °C) anoxic hydrolysis of ferrous monosulfides leads to pyrite. Thermodynamic functions are calculated for elementary reactions of hydrolysis and carbonation of olivine and pyroxene and E-pH diagrams are analyzed. It is shown that the hydrolysis of the iron endmember is endothermic and can proceed within the exothermic hydrolysis of the magnesium endmember and also within the exothermic reactions of carbonations. The distinction between three products of the iron hydrolysis, magnetite, goethite and hematite is determined with E-pH diagrams. The hydrolysis/oxidation of the sulfides mackinawite/troilite/pyrrhotite is highly endothermic but can proceed within the heat produced by the exothermic hydrolyses and carbonations of ferromagnesian silicates and also by other sources such as magma, hydrothermal sources, impacts. These theoretical results are confirmed by the products observed in several related laboratory experiments. The case of radiolyzed water is studied. It is shown that magnetite and ferric oxides/hydroxides such as ferric trihydroxide, goethite/lepidocrocite and hematite are formed in oxic hydrolysis of ferromagnesian silicates at 25 °C and 350 °C. Oxic oxidation of ferrous monosulfides at 25 °C leads mainly to pyrite and ferric oxides/hydroxides such as

  1. Method of decontamination for uranium oxide particles floating in liquid waste

    International Nuclear Information System (INIS)

    Terakado, Tsutomu; Ebara, Tsuneo; Sato, Kuniaki.

    1981-01-01

    Purpose: To rapidly treat liquid waste containing uranium oxide particles floating in it and to enable substantially complete decontamination. Method: An iron salt such as ferrous sulfate or the like is added to liquid waste with floating uranium oxide particles, an alkaline solution such as caustic soda or the like is then added to the liquid waste while feeding compressed air at 0.1 to 0.02 l/sec. per ton of liquid waste, and the pH of the liquid waste is made to from 6.5 to 7.5. Thereafter, the feed of compressed air is stopped, the liquid waste is allowed to stand, and is then filtered. (Aizawa, K.)

  2. Magnesium Oxide

    Science.gov (United States)

    Magnesium is an element your body needs to function normally. Magnesium oxide may be used for different reasons. Some people use it as ... one to four times daily depending on which brand is used and what condition you have. Follow ...

  3. A modular continuous flow reactor system for the selective bio-oxidation of iron and precipitation of schwertmannite from mine-impacted waters.

    Science.gov (United States)

    Hedrich, Sabrina; Johnson, D Barrie

    2012-02-01

    A novel modular bioremediation system which facilitates the selective removal of soluble iron from extremely acidic (pH ∼2) metal-rich wastewaters by ferrous iron oxidation and selective precipitation of the ferric iron produced is described. In the first of the three modules, rapid ferrous iron oxidation was mediated by the recently-characterized iron-oxidizing autotrophic acidophile, "Ferrovum myxofaciens", which grew as long "streamers" within the reactor. Over 90% of the iron present in influent test liquors containing 280mg/L iron was oxidized at a dilution rate of 0.41h(-1), in a proton-consuming reaction. The ferric iron-rich solutions produced were pumped into a second reactor where controlled addition of sodium hydroxide caused the water pH to increase to 3.5 and ferric iron to precipitate as the mineral schwertmannite. Addition of a flocculating agent promoted rapid aggregation and settling of the fine-grain schwertmannite particles. A third passive module (a packed-bed bioreactor, also inoculated with "Fv. myxofaciens") acted as a polishing reactor, lowering soluble iron concentrations in the processed water to iron from a synthetic acidic (pH 2.1) mine water that contained soluble aluminum, copper, manganese and zinc in addition to iron. Schwertmannite was again produced, with little or no co-precipitation of other metals. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Iron Oxides

    Energy Technology Data Exchange (ETDEWEB)

    Qafoku, Nikolla; Amonette, James E.

    2016-09-19

    Abstract: Fe oxides are common clay-sized oxide, oxyhydroxide and hydroxide soil minerals. They are compounds of Fe, O, and H that have structures based on close-packed arrays of O. The octahedral and tetrahedral cavities within these arrays are filled with either Fe3+ or Fe2+ to form Fe(O/OH)6, FeO6, or FeO4 structural units. All of the naturally occurring Fe oxide minerals usually undergo some degree of isomorphous substitution of other metal ions for Fe in their structures. Relatively simple techniques may be used to identify Fe oxides in the field based on their typical colors and magnetic properties. In the laboratory, a variety of instrumental techniques can be used to confirm phase identity and to quantify amount. Of these, X-ray diffraction, infrared spectroscopy, electron microscopy, thermal analysis, and Mössbauer spectroscopy are the most commonly used techniques. As oxides, the functional groups on their surfaces may have positive, negative, or no charge depending on pH and on the concentration and nature of other ions in the contact solution. A net positive surface charge usually is observed in soils because Fe oxides have a point-of-zero-charge in the neutral or slightly basic pHs. The functional groups on the surface form complexes with cations and anions from the aqueous phase. Their sorption and electron-buffering properties significantly affect the geochemical cycles of almost all elements having agronomic or environmental significance.

  5. Effects of Low-temperature Pre-oxidation on the Titanomagnetite Ore Structure and Reduction Behaviors in a Fluidized Bed

    Science.gov (United States)

    Adetoro, Ajala Adewole; Sun, Haoyan; He, Shengyi; Zhu, Qingshan; Li, Hongzhong

    2018-04-01

    With respect to high efficient utilization of low-grade iron ore resource, the behavior of low-temperature "973 K to 1123 K (700 °C to 850 °C)" oxidation, on the phase transition of SA TTM ore (South African titanomagnetite), and its effect on subsequent reduction was investigated. The results showed that hematite and rutile are the oxidation product below 1048 K (775 °C), while pseudobrookite is the stable phase above 1073 K (800 °C). With the increase in temperature and oxidation time, there is a competitive relationship between the amount of hematite and pseudobrookite generated. The reduction efficiency of SA TTM was significantly improved by oxidation pretreatment, primarily due to the dissociation of titania-ferrous oxides to more easily reducible hematite. But the generation of pseudobrookite phase decreases the amount of free hematite available for reduction, which weakens the improvement effect of pre-oxidation. The equilibrium relationship between the metallization degree and the gas reduction potential for TTM ore with pre-oxidation treatment has been built. Finally, the reduction metallization degree for the first and second step can be improved averagely by 16.67 and 3.45 pct, respectively, for sample pre-oxidized at 1098 K (825 °C) for 15 and 90 minutes, while 26.96 and 7.4 pct, improvement is achieved for sample pre-oxidized at a lower temperature of 1048 K (775 °C) for 120 minutes.

  6. Safety assessment of chronic oral exposure to iron oxide nanoparticles

    Science.gov (United States)

    Chamorro, Susana; Gutiérrez, Lucía; Vaquero, María Pilar; Verdoy, Dolores; Salas, Gorka; Luengo, Yurena; Brenes, Agustín; José Teran, Francisco

    2015-05-01

    Iron oxide nanoparticles with engineered physical and biochemical properties are finding a rapidly increasing number of biomedical applications. However, a wide variety of safety concerns, especially those related to oral exposure, still need to be addressed for iron oxide nanoparticles in order to reach clinical practice. Here, we report on the effects of chronic oral exposure to low doses of γ-Fe2O3 nanoparticles in growing chickens. Animal observation, weight, and diet intake reveal no adverse signs, symptoms, or mortality. No nanoparticle accumulation was observed in liver, spleen, and duodenum, with feces as the main excretion route. Liver iron level and duodenal villi morphology reflect the bioavailability of the iron released from the partial transformation of γ-Fe2O3 nanoparticles in the acid gastric environment. Duodenal gene expression studies related to the absorption of iron from γ-Fe2O3 nanoparticles indicate the enhancement of a ferric over ferrous pathway supporting the role of mucins. Our findings reveal that oral administration of iron oxide nanoparticles is a safe route for drug delivery at low nanoparticle doses.

  7. Safety assessment of chronic oral exposure to iron oxide nanoparticles

    International Nuclear Information System (INIS)

    Chamorro, Susana; Vaquero, María Pilar; Brenes, Agustín; Gutiérrez, Lucía; Salas, Gorka; Luengo, Yurena; Verdoy, Dolores; José Teran, Francisco

    2015-01-01

    Iron oxide nanoparticles with engineered physical and biochemical properties are finding a rapidly increasing number of biomedical applications. However, a wide variety of safety concerns, especially those related to oral exposure, still need to be addressed for iron oxide nanoparticles in order to reach clinical practice. Here, we report on the effects of chronic oral exposure to low doses of γ-Fe 2 O 3 nanoparticles in growing chickens. Animal observation, weight, and diet intake reveal no adverse signs, symptoms, or mortality. No nanoparticle accumulation was observed in liver, spleen, and duodenum, with feces as the main excretion route. Liver iron level and duodenal villi morphology reflect the bioavailability of the iron released from the partial transformation of γ-Fe 2 O 3 nanoparticles in the acid gastric environment. Duodenal gene expression studies related to the absorption of iron from γ-Fe 2 O 3 nanoparticles indicate the enhancement of a ferric over ferrous pathway supporting the role of mucins. Our findings reveal that oral administration of iron oxide nanoparticles is a safe route for drug delivery at low nanoparticle doses. (paper)

  8. Oxidative stress in preeclampsia and the role of free fetal hemoglobin

    Directory of Open Access Journals (Sweden)

    Stefan Rocco Hansson

    2015-01-01

    Full Text Available Preeclampsia is a leading cause of pregnancy complications and affects 3–7 % of pregnant women. This review summarizes the current knowledge of a new potential etiology of the disease, with a special focus on hemoglobin-induced oxidative stress. Furthermore, we also suggest hemoglobin as a potential target for therapy. Gene and protein profiling studies have shown increased expression and accumulation of free fetal hemoglobin in the preeclamptic placenta. Predominantly due to oxidative damage to the placental barrier, fetal hemoglobin leaks over to the maternal circulation. Free hemoglobin and its metabolites are toxic in several ways; a ferrous hemoglobin (Fe2+ binds strongly to the vasodilator nitric oxide and reduces the availability of free nitric oxide, which results in vasoconstriction, b hemoglobin (Fe2+ with bound oxygen spontaneously generates free oxygen radicals and c the heme groups create an inflammatory response by inducing activation of neutrophils and cytokine production. The endogenous protein α1-microglobulin, with radical and heme binding properties, has shown both ex vivo and in vivo to have the ability to counteract free hemoglobin-induced placental and kidney damage. Oxidative stress in general, and more specifically fetal hemoglobin-induced oxidative stress, could play a key role in the pathology of preeclampsia seen both in the placenta and ultimately in the maternal endothelium.

  9. Oxidation catalyst

    Science.gov (United States)

    Ceyer, Sylvia T.; Lahr, David L.

    2010-11-09

    The present invention generally relates to catalyst systems and methods for oxidation of carbon monoxide. The invention involves catalyst compositions which may be advantageously altered by, for example, modification of the catalyst surface to enhance catalyst performance. Catalyst systems of the present invention may be capable of performing the oxidation of carbon monoxide at relatively lower temperatures (e.g., 200 K and below) and at relatively higher reaction rates than known catalysts. Additionally, catalyst systems disclosed herein may be substantially lower in cost than current commercial catalysts. Such catalyst systems may be useful in, for example, catalytic converters, fuel cells, sensors, and the like.

  10. Comparative proteomic analysis of sulfur-oxidizing Acidithiobacillus ferrooxidans CCM 4253 cultures having lost the ability to couple anaerobic elemental sulfur oxidation with ferric iron reduction.

    Science.gov (United States)

    Kucera, Jiri; Sedo, Ondrej; Potesil, David; Janiczek, Oldrich; Zdrahal, Zbynek; Mandl, Martin

    2016-09-01

    In extremely acidic environments, ferric iron can be a thermodynamically favorable electron acceptor during elemental sulfur oxidation by some Acidithiobacillus spp. under anoxic conditions. Quantitative 2D-PAGE proteomic analysis of a resting cell suspension of a sulfur-grown Acidithiobacillus ferrooxidans CCM 4253 subculture that had lost its iron-reducing activity revealed 147 protein spots that were downregulated relative to an iron-reducing resting cell suspension of the antecedent sulfur-oxidizing culture and 111 that were upregulated. Tandem mass spectrometric analysis of strongly downregulated spots identified several physiologically important proteins that apparently play roles in ferrous iron oxidation, including the outer membrane cytochrome Cyc2 and rusticyanin. Other strongly repressed proteins were associated with sulfur metabolism, including heterodisulfide reductase, thiosulfate:quinone oxidoreductase and sulfide:quinone reductase. Transcript-level analyses revealed additional downregulation of other respiratory genes. Components of the iron-oxidizing system thus apparently play central roles in anaerobic sulfur oxidation coupled with ferric iron reduction in the studied microbial strain. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  11. Comparative bioavailability of ferrous succinate tablet formulations without correction for baseline circadian changes in iron concentration in healthy Chinese male subjects: a single-dose, randomized, 2-period crossover study.

    Science.gov (United States)

    Cao, Guo-Ying; Li, Ke-Xin; Jin, Peng-Fei; Yue, Xiang-Yang; Yang, Chen; Hu, Xin

    2011-12-01

    Ferrous succinate is used for the treatment of iron deficiency anemia. Determining the bioavailability of iron products is a challenge, because iron is naturally present in the blood and some tissues. Therefore, bioequivalence evaluation of ferrous formulations can be affected by the presence of endogenous iron species. Little information regarding the pharmacokinetics of ferrous supplements is available in the healthy Chinese population. The aim of the study was to assess the comparative bioavailability of 200-mg of a test (ferrous succinate,100 mg × 2, Hunan Huana Pharmaceutical Co., Ltd., Hunan, China) and reference (Sulifei, 100 mg × 2, Nanjing Jinling Pharmaceutical Co., Ltd., Nanjing, China) formulation in healthy Chinese male subjects. The study was conducted to meet Chinese State Food and Drug Administration regulatory requirements for approval of a generic formulation of ferrous succinate. This study utilized a single-dose randomized, 2-period, crossover design with alternate assignment of subjects to treatment (a single 200-mg [100 mg × 2]) or reference formulation groups. Both groups underwent a 4-day diet equilibration before 2 days of treatment and, finally, a 4-day washout period for the bioequivalence study. Blood samples were collected at 8:00 am on every diet equilibration day, 0 (baseline), 1, 2, 3, 4, 4.5, 5, 6, 9, 12, 24, and 36 hours after drug administration. Iron concentrations were determined using an inductively coupled plasma mass spectrometry. Subjects in both groups were given a standardized diet, with known amounts of iron and calories. The formulations were assumed to be bioequivalent if the 90% CI ratios for C(max) were within 70% to 143% and AUC(0-last) were within 80% to 125%-criteria established by the Chinese Food and Drug Administration. Tolerability was monitored throughout the study by assessing clinical parameters (vital signs, chemistry laboratory) and subject reports. Twenty healthy Han Chinese male subjects (mean age, 26

  12. Superiority of ferric chloride as coagulant over alum and ferrous sulphate at controlled pH and cost comparison of these coagulant

    International Nuclear Information System (INIS)

    Irfan, M.

    2008-01-01

    This study was conducted by author as a member of Specialty Chemical Division of Sitara Chemical Industries which is the largest chlor -alkali manufacturing industry in Pakistan. Sitara is also producing FeCl/sub 3/ as a byproduct to consume its additional quantity of chlorine produced during electrolysis of brine solution for caustic soda preparation. Most of the industries are using Alum along with other polymers for treatment of effluent waste water. Treatment system is based on sand bed filters. For coagulation of unwanted materials present in the water, Alum is being used with Anionic Polymer (Accofloc-A2125) as flocculent. But the ferric chloride is not only functions as a reactants to remove water impurities but it also functions as a both coagulant and a Flocculent. This study was conducted for finding best alternative chemicals to improve treated water quality. For this purpose Ferric Chloride (FeCl/sub 3/) is used as best alternative of alum for better removal of turbidity, heavy metals and micro organisms to eradicate above said problems and for better removal of turbidity, heavy metals and micro, organisms to eradicate health problems. As per lab scale results quality of treated water with Ferric Chloride (FeCl/sub 3/) proved better than that of Alum. The main objective of this research is to investigate the efficiency of coagulation and flocculation processes for removing suspended solids, colour and COD which present in significant quantity. Three types of coagulants were examined using standard jar test apparatus, i.e., aluminum sulphate (alum), ferric chloride (FeCl/sub 3/) and ferrous sulphate (FeSO/sub 4/). The effects of agitation speed, settling time, pH, coagulant dosages and temperature were examined. At 300 rpm of rapid mixing and 50 rpm of slow mixing and 60 minutes settling time, higher removals of suspended solids (over 95%), colour (90%) and COD (43%) were achieved at pH 4 and 12. FeCl/sub 3/ was found to be superior compared with other

  13. From nuclear field to cultural heritage conservation - Understanding of the long term corrosion mechanisms of ferrous alloys through multi scale characterization

    International Nuclear Information System (INIS)

    Neff, D.

    2012-01-01

    phenomena at the scale of an object. Taken together, these studies should lead to develop further protocols for diagnosis, treatment and conservation of cultural objects and reinforce the mechanistic models developed for the design of ferrous elements included in the storage facilities of radioactive waste. (author) [fr

  14. Characterization of Water Coordination to Ferrous Nitrosyl Complexes with fac-N2O, cis-N2O2, and N2O3 Donor Ligands.

    Science.gov (United States)

    McCracken, John; Cappillino, Patrick J; McNally, Joshua S; Krzyaniak, Matthew D; Howart, Michael; Tarves, Paul C; Caradonna, John P

    2015-07-06

    Electron paramagnetic resonance (EPR) experiments were done on a series of S = (3)/2 ferrous nitrosyl model complexes prepared with chelating ligands that mimic the 2-His-1-carboxylate facial triad iron binding motif of the mononuclear nonheme iron oxidases. These complexes formed a comparative family, {FeNO}(7)(N2Ox)(H2O)3-x with x = 1-3, where the labile coordination sites for the binding of NO and solvent water were fac for x = 1 and cis for x = 2. The continuous-wave EPR spectra of these three complexes were typical of high-spin S = (3)/2 transition-metal ions with resonances near g = 4 and 2. Orientation-selective hyperfine sublevel correlation (HYSCORE) spectra revealed cross peaks arising from the protons of coordinated water in a clean spectral window from g = 3.0 to 2.3. These cross peaks were absent for the {FeNO}(7)(N2O3) complex. HYSCORE spectra were analyzed using a straightforward model for defining the spin Hamiltonian parameters of bound water and showed that, for the {FeNO}(7)(N2O2)(H2O) complex, a single water conformer with an isotropic hyperfine coupling, Aiso = 0.0 ± 0.3 MHz, and a dipolar coupling of T = 4.8 ± 0.2 MHz could account for the data. For the {FeNO}(7)(N2O)(H2O)2 complex, the HYSCORE cross peaks assigned to coordinated water showed more frequency dispersion and were analyzed with discrete orientations and hyperfine couplings for the two water molecules that accounted for the observed orientation-selective contour shapes. The use of three-pulse electron spin echo envelope modulation (ESEEM) data to quantify the number of water ligands coordinated to the {FeNO}(7) centers was explored. For this aspect of the study, HYSCORE spectra were important for defining a spectral window where empirical integration of ESEEM spectra would be the most accurate.

  15. Safety test of a supplement, 5-aminolevulinic acid phosphate with sodium ferrous citrate, in diabetic patients treated with oral hypoglycemic agents

    Directory of Open Access Journals (Sweden)

    Naohide Yamashita

    2014-09-01

    Full Text Available Objective: This study aimed to examine the safety of 5-aminolevulinic acid phosphate (5-ALA with sodium ferrous citrate (SFC in diabetic patients treated with one or more oral hypoglycemic agents (OHAs. Background: Recent intervention studies performed in the USA and Japan have shown that a nutritional supplement of 5-ALA with SFC efficiently reduced blood glucose levels in pre-diabetic population without any adverse events. Thus, it was anticipated that 5-ALA with SFC may potentially be taken as a beneficial supplement by diabetic patients who were being treated with OHA therapy. Nevertheless, it is important to examine its safety and efficacy in diabetic population. Methods: This study was a prospective single-blinded, randomized, placebo-controlled and parallel-group comparison study. Medically treated diabetic patients between the ages of 30 and 75 were recruited from the Tokyo metropolitan area of Japan and 45 subjects were selected after screening. These subjects were randomly assigned to three groups: daily intake of 15mg 5-ALA, 50mg 5-ALA, and a placebo (n=15, respectively. The supplement or placebo was administered for 12 weeks followed by a four week washout period. The primary endpoint was safety and occurrence of hypoglycemic attack, while the secondary endpoint was changes of fasting blood glucose (FBG and hemoglobin A1c (HbA1c. Results: Adverse events related to 5-ALA with SFC were not observed in all the groups. Abnormalities in blood and urine tests were not observed either. Significant decrease in FBG was not detected in all the groups. However, there was a small but significant decrease in HbA1c at 4 and 8 week in the 15 mg 5-ALA group. Significant decrease in HbA1c was not observed in the 50 mg 5-ALA group, although a tendency to decrease after 4 weeks was apparent. Conclusion: 5-ALA with SFC is a safe and potentially beneficial supplement if taken by diabetic patients treated with OHAs.

  16. AFM measurements on ferrous materials

    Directory of Open Access Journals (Sweden)

    Ros Yáñez, T.

    2000-08-01

    Full Text Available The Atomic Force Microscope (AFM has been successfully used for the characterisation of the surface topography of a very wide range of materials. The AFM is an interesting technique to study the surface of materials and specifically to study surface effects in steel, e.g. after polishing and/or after etching. This technique allows not only to study the topography of the samples, but it is also a useful tool to obtain structural details of surfaces and for the identification of different phases. In this paper, some applications are shown concerning the study of the microstructure of multiphase-steels.

    El Microcopio de Fuerza Atómica (AFM es utilizado en la caracterización topográfica de una gran variedad de materiales. El AFM es una interesante técnica para el estudio de la superficie de los aceros, ya sea con ataque químico o no. Esta técnica es también una útil herramienta para obtener detalles estructurales en las superficies y en la identificación de fases. En este trabajo algunas de estas aplicaciones son mostradas en el estudio de la microestructura de aceros multifásicos.

  17. Machine Casting of Ferrous Alloys

    Science.gov (United States)

    1974-10-01

    Figure 55 Die casting machine. Shot sleeve at S, melt furnace at M, ladle preheat at L. Figure 56 Aluminum die casting top surface. Risers removed... ladle and transferred to the shot sleeve. Upon pouring the metal, the ram is actuated and the casting made. To test the mechanical operation of...mnui i .MI iiiiiuH ’ -84- Figure 55. Die casting machine. Shot sleeve at S, melt furnace at M, ladle preheat at L. ■ ■ wmmm*mm

  18. Oxidative stress

    Directory of Open Access Journals (Sweden)

    Stevanović Jelka

    2012-01-01

    Full Text Available The unceasing need for oxygen is in contradiction to the fact that it is in fact toxic to mammals. Namely, its monovalent reduction can have as a consequence the production of short-living, chemically very active free radicals and certain non-radical agents (nitrogen-oxide, superoxide-anion-radicals, hydroxyl radicals, peroxyl radicals, singlet oxygen, peroxynitrite, hydrogen peroxide, hypochlorous acid, and others. There is no doubt that they have numerous positive roles, but when their production is stepped up to such an extent that the organism cannot eliminate them with its antioxidants (superoxide-dismutase, glutathione-peroxidase, catalase, transferrin, ceruloplasmin, reduced glutathion, and others, a series of disorders is developed that are jointly called „oxidative stress.“ The reactive oxygen species which characterize oxidative stress are capable of attacking all main classes of biological macromolecules, actually proteins, DNA and RNA molecules, and in particular lipids. The free radicals influence lipid peroxidation in cellular membranes, oxidative damage to DNA and RNA molecules, the development of genetic mutations, fragmentation, and the altered function of various protein molecules. All of this results in the following consequences: disrupted permeability of cellular membranes, disrupted cellular signalization and ion homeostasis, reduced or loss of function of damaged proteins, and similar. That is why the free radicals that are released during oxidative stress are considered pathogenic agents of numerous diseases and ageing. The type of damage that will occur, and when it will take place, depends on the nature of the free radicals, their site of action and their source. [Projekat Ministarstva nauke Republike Srbije, br. 173034, br. 175061 i br. 31085

  19. No effect of H2O degassing on the oxidation state of hydrous rhyolite magmas: a comparison of pre- and post-eruptive Fe2+ concentrations in six obsidian samples from the Mexican and Cascade arcs

    Science.gov (United States)

    Waters, L.; Lange, R. A.

    2011-12-01

    The extent to which degassing affects the oxidation state of arc magmas is widely debated. Several researchers have examined how degassing of mixed H-C-O-S-Cl fluids may change the Fe3+/FeT ratio of magmas, and it has been proposed that degassing may induce either oxidation or reduction depending on the initial oxidation state. A commonly proposed oxidation reaction is related to H2O degassing: H2O (melt) + 2FeO (melt) = H2 (fluid) + Fe2O3 (melt). Another mechanism by which H2O degassing can affect the iron redox state is if dissolved water affects the activity of ferrous and/or ferric iron in the melt. Although Moore et al. (1995) presented experiments showing no evidence of an affect of dissolved water on the activity of the ferric-ferrous ratio in silicate melts, other experimental results (e.g., Baker and Rutherford, 1996; Gaillard et al., 2001; 2003) indicate that there may be such an effect in rhyolite liquids. It has long been understood that rhyolites, owing to their low total iron concentrations, are more sensitive than other magma types to degassing-induced change in redox state. Therefore, a rigorous test of whether H2O degassing affects the redox state of arc magmas is best evaluated on rhyolites. In this study, a comparison is made between the pre-eruptive (pre-degassing) Fe2+ concentrations in six, phenocryst-poor (volatiles, as indicated by the low loss on ignition values (LOI ≤ 0.7 wt%). In order to test how much oxidation of ferrous iron occurred as a consequence of that degassing, we measured the ferrous iron concentration in the bulk samples by titration, using the Wilson (1960) method, which was successfully tested again three USGS and one Canadian Geological Survey standards. Our results indicate no detectable change within analytical error between pre- and post-eruptive FeO concentrations, with an average deviation of 0.09 wt% and a maximum deviation of 0.15 wt%. Our results show that H2O degassing has no effect on the redox state of

  20. Oxidative dissolution of spent fuel and release of nuclides from a copper/iron canister. Model developments and applications

    Energy Technology Data Exchange (ETDEWEB)

    Longcheng Liu

    2001-12-01

    Three models have been developed and applied in the performance assessment of a final repository. They are based on accepted theories and experimental results for known and possible mechanisms that may dominate in the oxidative dissolution of spent fuel and the release of nuclides from a canister. Assuming that the canister is breached at an early stage after disposal, the three models describe three sub-systems in the near field of the repository, in which the governing processes and mechanisms are quite different. In the model for the oxidative dissolution of the fuel matrix, a set of kinetic descriptions is provided that describes the oxidative dissolution of the fuel matrix and the release of the embedded nuclides. In particular, the effect of autocatalytic reduction of hexavalent uranium by dissolved H{sub 2}, using UO{sub 2} (s) on the fuel pellets as a catalyst, is taken into account. The simulation results suggest that most of the radiolytic oxidants will be consumed by the oxidation of the fuel matrix, and that much less will be depleted by dissolved ferrous iron. Most of the radiolytically produced hexavalent uranium will be reduced by the autocatalytic reaction with H{sub 2} on the fuel surface. It will reprecipitate as UO{sub 2} (s) on the fuel surface, and thus very little net oxidation of the fuel will take place. In the reactive transport model, the interactions of multiple processes within a defective canister are described, in which numerous redox reactions take place as multiple species diffuse. The effect of corrosion of the cast iron insert of the canister and the reduction of dissolved hexavalent uranium by ferrous iron sorbed onto iron corrosion products and by dissolved H{sub 2} are particularly included. Scoping calculations suggest that corrosion of the iron insert will occur primarily under anaerobic conditions. The escaping oxidants from the fuel rods will migrate toward the iron insert. Much of these oxidants will, however, be consumed

  1. Removal of organic pollutants from industrial wastewater by applying photo-Fenton oxidation technology

    Directory of Open Access Journals (Sweden)

    Ebrahiem E. Ebrahiem

    2017-05-01

    Full Text Available The general strategy of this study was based on evaluation of the possibility of applying advanced photo-oxidation technique (Fenton oxidation process for removal of the residuals organic pollutants present in cosmetic wastewater. The different parameters that affect the chemical oxidation process for dyes in their aqueous solutions were studied by using Fenton’s reaction. These parameters are pH, hydrogen peroxide (H2O2 dose, ferrous sulfate (FeSO4·7H2O dose, Initial dye concentration, and time. The optimum conditions were found to be: pH 3, the dose of 1 ml/l H2O2 and 0.75 g/l for Fe(II and Fe(III and reaction time 40 min. Finally, chemical oxygen demands (COD, before and after oxidation process was measured to ensure the entire destruction of organic dyes during their removal from wastewater. The experimental results show that Fenton’s oxidation process successfully achieved very good removal efficiency over 95%.

  2. Evaluation of free radical scavenging and anti-oxidative capacity of polydatin-nanostructured lipid carriers

    Science.gov (United States)

    Meng, Xiang-Ping; Shi, Fan; Li, Hai-Jie; Yin, Li-De; Wang, Yi-Fei; Wang, Zhi-ping; Chen, Tong-sheng

    2016-10-01

    Cellular damage induced by free-radicals like reactive oxygen species has been implicated in several diseases. 2, 2-azobis(2-amidino-propane) dihydrochloride(AAPH) generates two potent ROS capable of inducing lipid peroxidation: alkoxy radical(RO-) and peroxy radical (ROO-). These radicals are similar to those that are physiologically active and thus might initiate a cascade of intracellular toxic events leading to oxidation, lipid peroxidation, DNA damage and subsequent cell death. Hence naturally anti-oxidant play a vital role in combating these conditions. In this study, polydatin loaded nanostructured lipid carriers (Pol-NLC) was prepared by hot melting and then high pressure homogenization technique. The effects of Pol-NLC on free radical scavenging and anti-oxidative capacity is investigated. The particle size and zeta potential of Pol-NLC were 113.9 +/- 1.1 nm and -16.3 1 +/- 0.27 mV, respectively. By free radical scavenging assays, the IC50 value of Pol-NLC were 28.71, 9.83 μg/mL with DPPH, ABTS assay respectively, and 0.143 mg ferrous sulfate/1 mg Pol-NLC with FRAP assay. These results indicated that the antioxidant properties of Pol-NLC hold great potential used as an alternative to more toxic synthetic anti-oxidants as an additive in food, cosmetic and pharmaceutical preparations for the oxidative diseases treatment.

  3. Physiology and Mechanism of Phototrophic Fe(II) Oxidation by Rhodopseudomonas palustris TIE-1

    Science.gov (United States)

    Jiao, Y.; Newman, D.

    2007-12-01

    Phototrophic Fe(II)-oxidizing bacteria use electrons from ferrous iron [Fe(II)] and energy from light to drive reductive CO2 fixation. This metabolism is thought to be ancient in origin, and plays an important role in environmental iron cycling. It has been implicated in the deposition of Banded Iron Formations, a class of ancient sedimentary iron deposits. Consistent with this hypothesis, we discovered that hydrogen gas, a thermodynamically favorable electron donor to Fe(II), in an Archean atmosphere would not have inhibited phototrophic Fe(II) oxidation. To understand this physiology and the connection to BIF formation at the molecular level, the mechanisms of phototrophic Fe(II) oxidation were examined in a model organism Rhodopseudomonas palustris TIE-1. Increased expression of a putative decaheme c-type cytochrome, encoded by pioA, was observed when cells were grown under Fe(II)-oxidizing conditions. Two genes located immediately downstream of pioA in the same operon, pioB and pioC, encode a putative outer membrane beta-barrel protein and a putative high potential iron-sulfur protein, respectively. Deletion studies demonstrated that all three genes are involved in phototrophic Fe(II) oxidation. This study provides our first insight into the molecular mechanisms of this metabolism, which will be further characterized by in vitro biochemical studies.

  4. A comparative study of the treatment of ethylene plant spent caustic by neutralization and classical and advanced oxidation.

    Science.gov (United States)

    Hawari, Alaa; Ramadan, Hasanat; Abu-Reesh, Ibrahim; Ouederni, Mabrouk

    2015-03-15

    The treatment of spent caustic produced from an ethylene plant was investigated. In the case of neutralization alone it was found that the maximum removal of sulfide was at pH values below 5.5. The higher percentage removal of sulfides (99% at pH = 1.5) was accompanied with the highest COD removal (88%). For classical oxidation using H2O2 the maximum COD removal percentage reached 89% at pH = 2.5 and at a hydrogen peroxide concentration of 19 mM/L. For the advanced oxidation using Fenton's process it was found that the maximum COD removal of 96.5% was achieved at a hydrogen peroxide/ferrous sulfate ratio of (7:1). Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Poly(acrylic acid)-directed synthesis of colloidally stable single domain magnetite nanoparticles via partial oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Altan, Cem L. [Department of Chemical Engineering, Yeditepe University, Istanbul 34755 (Turkey); Laboratory of Materials and Interface Chemistry & Soft Matter cryoTEM Research Unit, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven 5600 MB (Netherlands); Gurten, Berna [Department of Chemical Engineering, Yeditepe University, Istanbul 34755 (Turkey); Sadza, Roel [Laboratory of Materials and Interface Chemistry & Soft Matter cryoTEM Research Unit, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven 5600 MB (Netherlands); Yenigul, Elcin [Department of Chemical Engineering, Yeditepe University, Istanbul 34755 (Turkey); Sommerdijk, Nico A.J.M., E-mail: n.sommerdijk@tue.nl [Laboratory of Materials and Interface Chemistry & Soft Matter cryoTEM Research Unit, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven 5600 MB (Netherlands); Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven 5600 MB (Netherlands); Bucak, Seyda, E-mail: seyda@yeditepe.edu.tr [Department of Chemical Engineering, Yeditepe University, Istanbul 34755 (Turkey)

    2016-10-15

    Octahedral, single domain magnetite nanoparticles with average size of ~55 nm were synthesized through oxidative aging of a ferrous hydroxide (Fe(OH){sub 2}) precursor at high pH in water. The synthesis was also carried out in the presence of the hydrophilic polymer poly(acrylic acid). Presence of the polymer changed the particle morphology from octahedral to spherical while average size decreased to 40–50 nm. Although these particles have a tendency to precipitate due to their high magnetic moment, dispersions of these particles were obtained in the presence of this particular polymer which made the particles stable in water for several days making them suitable for various biotechnological applications such as cell separation owing to their low toxicity. - Highlights: • Stable, single domain magnetite nanoparticles are synthesized via partial oxidation. • Particles are readily stabilized in water by a biocompatible polymer. • Steric barrier is essential for the stabilization of large magnetite nanoparticles.

  6. Storage conditions and packaging greatly affects the stability of fortified wheat flour: Influence on vitamin A, iron, zinc, and oxidation.

    Science.gov (United States)

    Hemery, Youna M; Laillou, Arnaud; Fontan, Laura; Jallier, Vincent; Moench-Pfanner, Regina; Berger, Jacques; Avallone, Sylvie

    2018-02-01

    Micronutrient deficiencies result in irreversible physical and cognitive consequences. Fortification of flour is widely applied to address micronutrient deficiencies, but vitamin losses can occur during the storage of fortified products. This work aimed at assessing the combined influence of different factors on vitamin A retention and the oxidative status of wheat flours: storage duration (up to 6months), temperature during storage, relative humidity within storage facilities, type of packaging (oxygen-permeable or not), and premix composition (with or without ferrous sulphate). Vitamin A degradation was high and occurred rapidly: more than 45% was lost within 3months in the mildest conditions, whereas over 85% was lost within 3months in the most severe conditions. Vitamin A retention was related to the extent of oxidation reactions that occurred in flours during storage, and the factors that mostly affected vitamin A retention were the storage duration, the type of packaging and the temperature. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Phytochemically evaluation and net anti-oxidant activity of Tunisian Melia azedarach leaves extract from their ProAntidex parameter

    Directory of Open Access Journals (Sweden)

    Maroua Akacha

    2016-06-01

    Full Text Available Phytotherapy is a discipline which is interested in the design, the preparation and the interpretation of structure activity relationship of the natural bioactive molecules. In this context, ethanolic leaves extract of Melia azedarach L. was phytochemically analysed on the bases of HPLC and by GC–MS. Extract wase tested for his in vitro antioxidant activities by 1,1-diphenyl-2-picrylhydrazyl (DPPH, H2O2, hydroxyl radical scavenging activity, Ferric Reducing Power (FRP and Ferrous ion chelating abilities methods. The antioxidant activity of the extract was analyzed simultaneously with their pro-oxidant capacity. The ratio of pro-oxidant to the antioxidant activity (ProAntidex represents a useful index of the net free radical scavenging potential of the synthesized compounds. Tested extract showed significant antioxidant activity with a moderate ProAntidex.

  8. Removal of organic pollutants from produced water using Fenton oxidation

    Science.gov (United States)

    Afzal, Talia; Hasnain Isa, Mohamed; Mustafa, Muhammad Raza ul

    2018-03-01

    Produced water (PW) is the largest stream of wastewater from oil and gas exploration. It is highly polluted and requires proper treatment before disposal. The main objective of this study was to investigate the effectiveness of Fenton oxidation in degradation of organic matter in PW. The role of operating factors viz., H2O2 concentration (0.12 × 10-3 moles/L to 3 moles/L), [H2O2]/[Fe2+] molar ratio (2 to 75), and reaction time (30 to 200 minutes), on COD removal was determined through a series of batch experiments conducted in acidic environment at room temperature. The experiments were conducted with 500 mL PW samples in 1L glass beakers covered on the outside with aluminum foil to protect them from sunlight. Pre-decided amounts of ferrous sulfate heptahydrate (FeSO4.7H2O) and hydrogen peroxide (H2O2) were added to initiate the Fenton reaction. An increase in COD removal was observed with increase in reaction time and [H2O2]/[Fe2+] molar ratio. COD removal also increased with H2O2 concentration up to 0.01 moles/L; further increase in H2O2 concentration decreased the COD removal efficiency. Over 90% COD removal was achieved under optimum reaction conditions. The study indicates that Fenton oxidation is effective for remediation of PW in terms of organic matter removal.

  9. Destruction of nitrotoluenes in wastewater by Electro-Fenton oxidation.

    Science.gov (United States)

    Chen, Wen-Shing; Lin, Sheng-Zhi

    2009-09-15

    Electrolytic degradation of dinitrotoluenes (DNTs) and 2,4,6-trinitrotoluene (TNT) in wastewater was conducted by Electro-Fenton's reagents. The batch-wise experiments were carried out to elucidate the influence of various operating variables on the electrolytic behavior, including electrode potential, oxygen dosage, electrolytic temperature, acidity of wastewater and dosage of ferrous ions. It deserves to note that the nitrotoluenes contained could be completely decomposed by Electro-Fenton's reagents, wherein hydrogen peroxide was in situ generated from cathodic reduction of oxygen, supplied mainly by anodic oxidation of water. During the electrochemical process, the influence of electrolytic temperature on the degradation of nitrotoluenes is the most significant, followed by electrode potential, acidity of wastewater and oxygen dosage. Based on the spectra analyzed by gas chromatograph/mass spectrometer (GC/MS), it is proposed that initial denitration of 2,4-DNT and/or 2,6-DNT gives rise to formation of o-mononitrotoluene, which undergoes the cleavage of nitro group into toluene, followed by oxidation of methyl group to benzoic acid and subsequent decarboxylation. It is believed that the electrolytic method established is potentially applied to dispose wastewater from toluene nitration processes in practice.

  10. Nitric oxide heme interactions in nitrophorin from Cimex lectularius

    Energy Technology Data Exchange (ETDEWEB)

    Christmann, R.; Auerbach, H., E-mail: auerbach@physik.uni-kl.de [University of Kaiserslautern, Department of Physics (Germany); Berry, R. E.; Walker, F. A. [The University of Arizona, Department of Chemistry and Biochemistry (United States); Schünemann, V. [University of Kaiserslautern, Department of Physics (Germany)

    2016-12-15

    The nitrophorin from the bedbug Cimex lectularius (cNP) is a nitric oxide (NO) carrying protein. Like the nitrophorins (rNPs) from the kissing bug Rhodnius prolixus, cNP forms a stable heme Fe(III)-NO complex, where the NO can be stored reversibly for a long period of time. In both cases, the NPs are found in the salivary glands of blood-sucking bugs. The insects use the nitrophorins to transport the NO to the victim’s tissues, resulting in vasodilation and reduced blood coagulation. However, the structure of cNP is significantly different to those of the rNPs from Rhodnius prolixus. Furthermore, the cNP can bind a second NO molecule to the proximal heme cysteine when present at higher concentrations. High field Mössbauer spectroscopy on {sup 57}Fe enriched cNP complexed with NO shows reduction of the heme iron and formation of a ferrous nitric oxide (Fe(II)-NO) complex. Density functional theory calculations reproduce the experimental Mössbauer parameters and confirm this observation.

  11. Changes of turbidity during the phenol oxidation by photo-Fenton treatment.

    Science.gov (United States)

    Villota, Natalia; Camarero, Luis M; Lomas, Jose M; Perez, Jonatan

    2014-11-01

    Turbidity presented by phenol solutions oxidized with Fenton reagent shows the tendency of a first order intermediate kinetics. Thus, turbidity can be considered a representative parameter of the presence of intermediate oxidation species, which are generated along the decomposition of toxic and reluctant contaminants, such as phenol. Moreover, that parameter presents a linear dependence with the catalyst dosage, but is also determined by the initial contaminant load. When analyzing the oxidation mechanism of phenol, it is found that the maximum turbidity occurs when the treatment is carried out at oxidant to phenol molar ratios R = 4.0. These oxidation conditions correspond to the presence of a reaction mixture mainly composed of dihydroxylated rings, precursors of the muconic acid formation. The oxidation via "para" comprises the formation reactions of charge transfer complexes (quinhydrone), between the para-dihydroxylated intermediates (hydroquinone) and the para-substituted quinones (p-benzoquinone), which are quite unstable and reactive species, quickly decomposed into hydroxyhydroquinones. Working with oxidant ratios up to R = 6.0, the maximum observed value of turbidity in the oxidized solutions is kept almost constant. It is found that, in these conditions, the pyrogallol formation is maximal, what is generated through the degradation of ortho-species (catechol and ortho-benzoquinone) and meta-substituted (resorcinol). Operating with ratios over R = 6.0, these intermediates are decomposed into biodegradable acids, generating lower turbidity in the solution. Then, the residual turbidity is a function of the molar ratio of the ferrous ions vs. moles of oxidant utilized in the essays, that lets to estimate the stoichiometric dosage of catalyst as 20 mg/L at pH = 3.0, whereas operating in stoichiometric conditions, R = 14.0, the residual turbidity of water results almost null.

  12. Light-induced oxidation of iron atoms in a photosensitive nitrile hydratase

    International Nuclear Information System (INIS)

    Honda, Jun; Sasabe, Hiroyuki; Teratani, Yoshitaka; Hirata, Akira; Kobayashi, Yoshio; Ambe, Fumitoshi; Nagamune, Teruyuki; Endo, Isao

    1992-01-01

    The photoactivation process of a photosensitive nitrile hydratase (NHase) from Rhodococcus sp. N-771 has been investigated by 57 Fe Moessbauer spectroscopy and magnetic susceptibility measurements in order to clarify the behavior of iron atoms in the enzyme. Moessbauer spectra of inactive NHase gave two symmetric-doublet components indicating the presence of two iron species, while that of the active NHase gave a single symmetric doublet indicating the presence of a single iron species. Magnetic susceptibility measurements of the inactive and active NHase both showed small effective magnetic moments. These results led to the conclusion that one of the two iron atoms incorporated in the NHase is oxidized during photoactivation, namely from a low spin ferrous to a low spin ferric state. This is the first observation of an intramolecular photooxidation phenomena involving iron in a single protein molecule. (author). 11 refs.; 3 figs.; 3 tabs

  13. Determination of thymine glycol residues in irradiated or oxidized DNA by formation of methylglyceric acid

    International Nuclear Information System (INIS)

    Schellenberg, K.A.; Shaeffer, J.

    1986-01-01

    Treatment of DNA solutions with X-irradiation various oxidants including hydrogen peroxide plus ferrous ion, hydrogen peroxide plus copper ion and ascorbate, permanganate, or sonication in the presence of dissolved oxygen all produced varying amounts of thymine glycol residues. After denaturing the DNA with heat, the glycol residues were reduced and labeled at the 6 position with tritium- labeled sodium borohydride. Subsequent reaction with anhydrous methanolic HCl gave a quantitative yield of the methyl ester of methylglyceric acid, which was determined by thin layer chromatography. The method, developed using thymidine as a model, was used to ascertain the requirements for glycol formation in DNA. It was shown that hydroxyl radical generating systems, permanganate, X-irradiation, or sonication in presence of oxygen were required, but hydrogen peroxide in the absence of iron or copper and ascorbate was inactive. Application to determination of DNA damage in vivo is being explored

  14. Angiotensin-I Converting Enzyme (ACE Inhibitory and Anti-Oxidant Activities of Sea Cucumber (Actinopyga lecanora Hydrolysates

    Directory of Open Access Journals (Sweden)

    Raheleh Ghanbari

    2015-12-01

    Full Text Available In recent years, food protein-derived hydrolysates have received considerable attention because of their numerous health benefits. Amongst the hydrolysates, those with anti-hypertensive and anti-oxidative activities are receiving special attention as both activities can play significant roles in preventing cardiovascular diseases. The present study investigated the angiotensin-I converting enzyme (ACE inhibitory and anti-oxidative activities of Actinopyga lecanora (A. lecanora hydrolysates, which had been prepared by alcalase, papain, bromelain, flavourzyme, pepsin, and trypsin under their optimum conditions. The alcalase hydrolysate showed the highest ACE inhibitory activity (69.8% after 8 h of hydrolysis while the highest anti-oxidative activities measured by 2,2-diphenyl 1-1-picrylhydrazyl radical scavenging (DPPH (56.00% and ferrous ion-chelating (FIC (59.00% methods were exhibited after 24 h and 8 h of hydrolysis, respectively. The ACE-inhibitory and anti-oxidative activities displayed dose-dependent trends, and increased with increasing protein hydrolysate concentrations. Moreover, strong positive correlations between angiotensin-I converting enzyme (ACE inhibitory and anti-oxidative activities were also observed. This study indicates that A. lecanora hydrolysate can be exploited as a source of functional food owing to its anti-oxidant as well as anti-hypertension functions.

  15. Combined crystallographic and spectroscopic analysis of Trematomus bernacchii hemoglobin highlights analogies and differences in the peculiar oxidation pathway of Antarctic fish hemoglobins.

    Science.gov (United States)

    Merlino, Antonello; Vitagliano, Luigi; Howes, Barry D; Verde, Cinzia; di Prisco, Guido; Smulevich, Giulietta; Sica, Filomena; Vergara, Alessandro

    2009-12-01

    Recent studies have demonstrated that hemoglobins isolated from Antarctic fish undergo peculiar oxidation processes. Here we show, by combining crystallographic and spectroscopic data, that the oxidation pathway of Trematomus bernacchii hemoglobin (HbTb) is distinct from that observed for the major component of Trematomus newnesi (Hb1Tn), despite the high sequence identity of the two proteins and structural similarity of their ferrous and fully oxidized states. Resonance Raman analysis of HbTb autoxidation upon air-exposure reveals the absence of the oxidized pentacoordinated state that was observed for Hb1Tn. The HbTb oxidation pathway is characterized by two ferric species: an aquo hexacoordinated high spin state and a bis-histidyl hexacoordinated low spin form, which appear in the early stages of the oxidation process. The high resolution structure of an intermediate along the oxidation pathway has been determined at 1.4 A resolution. The analysis of the electron density of the heme pocket shows, for both the alpha and the beta iron, the coexistence of multiple binding states. In this partially oxidized form, HbTb exhibits significant deviations from the canonical R state both at the local and global level. The analysis of these modifications highlights the structural correlation between key functional regions of the protein.

  16. Linking Thermodynamics to Pollutant Reduction Kinetics by Fe2+Bound to Iron Oxides.

    Science.gov (United States)

    Stewart, Sydney M; Hofstetter, Thomas B; Joshi, Prachi; Gorski, Christopher A

    2018-03-29

    Numerous studies have reported that pollutant reduction rates by ferrous iron (Fe 2+ ) are substantially enhanced in the presence of an iron (oxyhydr)oxide mineral. Developing a thermodynamic framework to explain this phenomenon has been historically difficult due to challenges in quantifying reduction potential ( E H ) values for oxide-bound Fe 2+ species. Recently, our group demonstrated that E H values for hematite- and goethite-bound Fe 2+ can be accurately calculated using Gibbs free energy of formation values. Here, we tested if calculated E H values for oxide-bound Fe 2+ could be used to develop a free energy relationship capable of describing variations in reduction rate constants of of substituted nitrobenzenes, a class of model pollutants that contain reducible aromatic nitro groups, using data collected here and compiled from the literature. All the data could be described by a single linear relationship between the logarithms of the surface-area-normalized rate constant ( k SA ) values and E H and pH values [log( k SA ) = - E H /0.059V - pH + 3.42]. This framework provides mechanistic insights into how the thermodynamic favorability of electron transfer from oxide-bound Fe 2+ relates to redox reaction kinetics.

  17. Advanced oxidation protein products are more related to metabolic syndrome components than biomarkers of lipid peroxidation.

    Science.gov (United States)

    Venturini, Danielle; Simão, Andréa Name Colado; Dichi, Isaias

    2015-09-01

    Although advanced oxidation protein products (AOPPs) have been reported as the most appropriate parameter for determination of oxidative stress in patients with metabolic syndrome (MetS), a direct comparison between protein and lipid peroxidation has not been performed yet. The aim of this study was to compare protein peroxidation with lipid peroxidation measured by 2 different methodologies (tert-butyl hydroperoxide-initiated chemiluminescence and ferrous oxidation-xylenol orange assay). The hypothesis of this study was that AOPPs would be more related to MetS than to oxidative markers of lipid peroxidation. This cross-sectional study evaluated 76 patients with MetS and 20 healthy subjects. Prooxidant-antioxidant index (PAI) assessed as AOPP/total radical-trapping antioxidant parameter ratio progressively increased (P protein (r = 0.275, P protein (r = 0.278, P protein peroxidation determined by AOPPs, and especially by PAI, is more related to MetS components than lipid peroxidation. In addition, PAI progressively increased with the number of MetS components. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Nitric Oxide Binds to and Modulates the Activity of a Pollen Specific Arabidopsis Diacylglycerol Kinase

    KAUST Repository

    Wong, Aloysius Tze

    2014-06-01

    Nitric oxide (NO) is an important signaling molecule in plants. In the pollen of Arabidopsis thaliana, NO causes re-orientation of the growing tube and this response is mediated by 3′,5′-cyclic guanosine monophosphate (cGMP). However, in plants, NO-sensors have remained somewhat elusive. Here, the findings of an NO-binding candidate, Arabidopsis thaliana DIACYLGLYCEROL KINASE 4 (ATDGK4; AT5G57690) is presented. In addition to the annotated diacylglycerol kinase domain, this molecule also harbors a predicted heme-NO/oxygen (H-NOX) binding site and a guanylyl cyclase (GC) catalytic domain which have been identified based on the alignment of functionally conserved amino acid residues across species. A 3D model of the molecule was constructed, and from which the locations of the kinase catalytic center, the ATP-binding site, the GC and H-NOX domains were estimated. Docking of ATP to the kinase catalytic center was also modeled. The recombinant ATDGK4 demonstrated kinase activity in vitro, catalyzing the ATP-dependent conversion of sn-1,2-diacylglycerol (DAG) to phosphatidic acid (PA). This activity was inhibited by the mammalian DAG kinase inhibitor R59949 and importantly also by the NO donors diethylamine NONOate (DEA NONOate) and sodium nitroprusside (SNP). Recombinant ATDGK4 also has GC activity in vitro, catalyzing the conversion of guanosine-5\\'-triphosphate (GTP) to cGMP. The catalytic domains of ATDGK4 kinase and GC may be independently regulated since the kinase but not the GC, was inhibited by NO while Ca2+ only stimulates the GC. It is likely that the DAG kinase product, PA, causes the release of Ca2+ from the intracellular stores and Ca2+ in turn activates the GC domain of ATDGK4 through a feedback mechanism. Analysis of publicly available microarray data has revealed that ATDGK4 is highly expressed in the pollen. Here, the pollen tubes of mis-expressing atdgk4 recorded slower growth rates than the wild-type (Col-0) and importantly, they showed altered

  19. Whey Peptide-Iron Complexes Increase the Oxidative Stability of Oil-in-Water Emulsions in Comparison to Iron Salts.

    Science.gov (United States)

    Caetano-Silva, Maria Elisa; Barros Mariutti, Lilian Regina; Bragagnolo, Neura; Bertoldo-Pacheco, Maria Teresa; Netto, Flavia Maria

    2018-02-28

    Food fortification with iron may favor lipid oxidation in both food matrices and the human body. This study aimed at evaluating the effect of peptide-iron complexation on lipid oxidation catalyzed by iron, using oil-in-water (O/W) emulsions as a model system. The extent of lipid oxidation of emulsions containing iron salts (FeSO 4 or FeCl 2 ) or iron complexes (peptide-iron complexes or ferrous bisglycinate) was evaluated during 7 days, measured as primary (peroxide value) and secondary products (TBARS and volatile compounds). Both salts catalyzed lipid oxidation, leading to peroxide values 2.6- to 4.6-fold higher than the values found for the peptide-iron complexes. The addition of the peptide-iron complexes resulted in the formation of lower amounts of secondary volatiles of lipid oxidation (up to 78-fold) than those of iron salts, possibly due to the antioxidant activity of the peptides and their capacity to keep iron apart from the lipid phase, since the iron atom is coordinated and takes part in a stable structure. The peptide-iron complexes showed potential to reduce the undesirable sensory changes in food products and to decrease the side effects related to free iron and the lipid damage of cell membranes in the organism, due to the lower reactivity of iron in the complexed form.

  20. Impact of nitrogen flushing and oil choice on the progression of lipid oxidation in unwashed fried sliced potato crisps.

    Science.gov (United States)

    Marasca, E; Greetham, D; Herring, S D; Fisk, I D

    2016-05-15

    Unwashed, sliced, batch-fried potato crisps have a unique texture and are growing in popularity in the UK/EU premium snack food market. In this study, the storage stability of unwashed sliced (high surface starch) potatoes (crisps) fried in regular sunflower oil (SO) or in high oleic sunflower oil (HOSO) was compared over accelerated shelf life testing (45°C, 6 weeks); with and without nitrogen gas flushing. Primary oxidation products (lipid hydroperoxides) were measured with a ferrous oxidation-xylenol orange (FOX) assay and volatile secondary oxidation products (hexanal) were quantified by using solid phase micro-extraction gas chromatography mass spectrometry (HS-SPME-GC/MS). Results revealed that crisps fried in SO were the least stable. Flushing the stored crisps with nitrogen gas proved to be effective in slowing down the oxidation rate after frying with sunflower oil, significantly stabilizing the crisps. However, crisps fried in HOSO were the most stable, with the lowest rate of development of oxidation markers, and this has previously not been shown for crisps with a high free starch content. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Metal-Catalyzed Oxidation of Protein Methionine Residues in Human Parathyroid Hormone (1-34): Formation of Homocysteine and a Novel Methionine-Dependent Hydrolysis Reaction

    Science.gov (United States)

    Mozziconacci, Olivier; Ji, Junyan A.; Wang, Y. John; Schöneich, Christian

    2013-01-01

    The oxidation of PTH(1-34) catalyzed by ferrous ethylenediaminetetraacetic acid (EDTA) is site-specific. The oxidation of PTH(1-34) is localized primarily to the residues Met[8] and His[9]. Beyond the transformation of Met[8] and His[9] into methionine sulfoxide and 2-oxo-histidine, respectively, we observed a hydrolytic cleavage between Met[8] and His[9]. This hydrolysis requires the presence of FeII and oxygen and can be prevented by diethylenetriaminepentaacetic acid (DTPA) and phosphate buffer. Conditions leading to this site-specific hydrolysis also promote the transformation of Met[8] into homocysteine, indicating that the hydrolysis and transformation of homocysteine may proceed through a common intermediate. PMID:23289936

  2. Synthesis, characterization and mechanistic insights of mycogenic iron oxide nanoparticles

    Science.gov (United States)

    Bhargava, Arpit; Jain, Navin; Barathi L., Manju; Akhtar, Mohd. Sayeed; Yun, Yeoung-Sang; Panwar, Jitendra

    2013-11-01

    In the present study, extracellular synthesis of iron oxide nanoparticles (IONPs) was achieved using Aspergillus japonicus isolate AJP01. The isolate demonstrated its ability to hydrolyze the precursor salt solution, a mixture of iron cyanide complexes, under ambient conditions. Hydrolysis of these complexes released ferric and ferrous ions, which underwent protein-mediated coprecipitation and controlled nucleation resulting in the formation of IONPs. Transmission electron microscopy, selected area electron diffraction pattern, energy dispersive spectroscopy and grazing incidence X-ray diffraction analysis confirmed the mycosynthesis of IONPs. The synthesized particles were cubic in shape with a size range of 60-70 nm with crystal structure corresponding to magnetite. Scanning electron microscopy analysis revealed the absence of IONPs on fungal biomass surface, indicating the extracellular nature of synthesis. Fourier transform infrared spectroscopy confirmed the presence of proteins on as-synthesised IONPs, which may confer their stability. Preliminary investigation indicated the role of proteins in the synthesis and stabilization of IONPs. On the basis of present findings, a probable mechanism for synthesis of IONPs is suggested. The simplicity and versatility of the present approach can be utilized for the synthesis of other nanomaterials.

  3. Development of evaluation method on flow-induced vibration and corrosion of components in two-phase flow by coupled analysis. 5. Evaluation of wall thinning rate with the coupled model of static electrochemical analysis and dynamic double oxide layer analysis

    International Nuclear Information System (INIS)

    Uchida, Shunsuke; Naitoh, Masanori; Okada, Hidetoshi; Uehara, Yasushi

    2008-01-01

    Wall thinning rates due to FAC were calculated with the coupled model of static electrochemical analysis and dynamic double oxide layer analysis at the identified danger zone. Anodic and cathodic current densities and ECPs were calculated with the static electrochemistry model and ferrous ion release rate determined by the anodic current density was used as input for the dynamic double oxide layer model. Thickness of oxide film and its characteristics determined by the dynamic double oxide layer model were used for the electrochemistry model to determine the resistances of cathodic current from the bulk to the surface and anodic current from the surface to the bulk. Two models were coupled to determine local corrosion rate and ECP for various corrosive conditions. The calculated results of the coupled models had good agreement with the measured ones. (author)

  4. RNA modifications by oxidation

    DEFF Research Database (Denmark)

    Poulsen, Henrik E; Specht, Elisabeth; Broedbaek, Kasper

    2012-01-01

    to encompass various classes of novel regulatory RNAs, including, e.g., microRNAs. It is well known that DNA is constantly oxidized and repaired by complex genome maintenance mechanisms. Analogously, RNA also undergoes significant oxidation, and there are now convincing data suggesting that oxidation......, and the consequent loss of integrity of RNA, is a mechanism for disease development. Oxidized RNA is found in a large variety of diseases, and interest has been especially devoted to degenerative brain diseases such as Alzheimer disease, in which up to 50-70% of specific mRNA molecules are reported oxidized, whereas...... other RNA molecules show virtually no oxidation. The iron-storage disease hemochromatosis exhibits the most prominent general increase in RNA oxidation ever observed. Oxidation of RNA primarily leads to strand breaks and to oxidative base modifications. Oxidized mRNA is recognized by the ribosomes...

  5. Simultaneous Fe(III) reduction and ammonia oxidation process in Anammox sludge.

    Science.gov (United States)

    Li, Xiang; Huang, Yong; Liu, Heng-Wei; Wu, Chuan; Bi, Wei; Yuan, Yi; Liu, Xin

    2018-02-01

    In recent years, there have been a number of reports on the phenomenon in which ferric iron (Fe(III)) is reduced to ferrous iron [Fe(II)] in anaerobic environments, accompanied by simultaneous oxidation of ammonia to NO 2 - , NO 3 - , or N 2. However, studies on the relevant reaction characteristics and mechanisms are rare. Recently, in research on the effect of Fe(III) on the activity of Anammox sludge, excess ammonia oxidization has also been found. Hence, in the present study, Fe(III) was used to serve as the electron acceptor instead of NO 2 - , and the feasibility and characteristics of Anammox coupled to Fe(III) reduction (termed Feammox) were investigated. After 160days of cultivation, the conversion rate of ammonia in the reactor was above 80%, accompanied by the production of a large amount of NO 3 - and a small amount of NO 2 - . The total nitrogen removal rate was up to 71.8%. Furthermore, quantities of Fe(II) were detected in the sludge fluorescence in situ hybridization (FISH) and denaturated gradient gel electrophoresis (DGGE) analyses further revealed that in the sludge, some Anammox bacteria were retained, and some microbes were enriched during the acclimatization process. We thus deduced that in Anammox sludge, Fe(III) reduction takes place together with ammonia oxidation to NO 2 - and NO 3 - along with the Anammox process. Copyright © 2017. Published by Elsevier B.V.

  6. Decomposition of nitrotoluenes from trinitrotoluene manufacturing process by Electro-Fenton oxidation.

    Science.gov (United States)

    Chen, Wen-Shing; Liang, Jing-Song

    2008-06-01

    Oxidative degradation of dinitrotoluene (DNT) isomers and 2,4,6-trinitrotoluene (TNT) in spent acid was conducted by Electro-Fenton's reagents. The electrolytic experiments were carried out to elucidate the influence of various operating parameters on the performance of mineralization of total organic compounds (TOC) in spent acid, including reaction temperature, dosage of oxygen, sulfuric acid concentration and dosage of ferrous ions. It deserves to note that organic compounds could be completely destructed by Electro-Fenton's reagent with in situ electrogenerated hydrogen peroxide obtained from cathodic reduction of oxygen, which was mainly supplied by anodic oxidation of water. Based on the spectra analyzed by gas chromatograph/mass spectrometer, it is proposed that initial denitration of 2,4,6-TNT gives rise to formation of 2,4-DNT and/or 2,6-DNT, which undergo the cleavage of nitro group into o-mononitrotoluene, followed by denitration to toluene and subsequent oxidation of the methyl group. Owing to the removal of both TOC and partial amounts of water simultaneously, the electrolytic method established is potentially applied to regenerate spent acid from toluene nitration processes in practice.

  7. Determination of uranium in uranium metal, uranium oxides, and uranyl nitrate solutions by potentiometric titration

    International Nuclear Information System (INIS)

    Tucker, H.L.; McElhaney, R.J.

    1983-01-01

    A simple, fast method for the determination of uranium in uranium metal, uranium oxides, and uranyl nitrate solutions has been adapted from the Davies-Gray volumetric method to meet the needs of Y-12. One-gram duplicate aliquots of uranium metal or uranium oxide are dissolved in 1:1 HNO 3 and concentrated H 2 SO 4 to sulfur trioxide fumes, and then diluted to 100-mL volume. Duplicate aliquots are then weighed for analysis. For uranyl nitrate samples, duplicate aliquots containing between 50 and 150 mg of U are weighed and analyzed directly. The weighed aliquot is transferred to a Berzelius beaker; 1.5 M sulfamic acid is added, followed in order by concentrated phosphoric acid, 1 M ferrous sulfate, and (after a 30-second interval) the oxidizing reagent. After a timed 3-minute waiting period, 100 mL of the 0.1% vanadyl sulfate-sulfuric acid mixture is added. The sample is then titrated past its endpoint with standard potassium dichromate, and the endpoint is determined by second derivative techniques on a mV/weight basis

  8. Photo-oxidation catalysts

    Science.gov (United States)

    Pitts, J Roland [Lakewood, CO; Liu, Ping [Irvine, CA; Smith, R Davis [Golden, CO

    2009-07-14

    Photo-oxidation catalysts and methods for cleaning a metal-based catalyst are disclosed. An exemplary catalyst system implementing a photo-oxidation catalyst may comprise a metal-based catalyst, and a photo-oxidation catalyst for cleaning the metal-based catalyst in the presence of light. The exposure to light enables the photo-oxidation catalyst to substantially oxidize absorbed contaminants and reduce accumulation of the contaminants on the metal-based catalyst. Applications are also disclosed.

  9. Phototrophic Fe(II)-oxidation in the chemocline of a ferruginous meromictic lake.

    Science.gov (United States)

    Walter, Xavier A; Picazo, Antonio; Miracle, Maria R; Vicente, Eduardo; Camacho, Antonio; Aragno, Michel; Zopfi, Jakob

    2014-01-01

    Precambrian Banded Iron Formation (BIF) deposition was conventionally attributed to the precipitation of iron-oxides resulting from the abiotic reaction of ferrous iron (Fe(II)) with photosynthetically produced oxygen. Earliest traces of oxygen date from 2.7 Ga, thus raising questions as to what may have caused BIF precipitation before oxygenic photosynthesis evolved. The discovery of anoxygenic phototrophic bacteria thriving through the oxidation of Fe(II) has provided support for a biological origin for some BIFs, but despite reports suggesting that anoxygenic phototrophs may oxidize Fe(II) in the environment, a model ecosystem of an ancient ocean where they are demonstrably active was lacking. Here we show that anoxygenic phototrophic bacteria contribute to Fe(II) oxidation in the water column of the ferruginous sulfate-poor, meromictic lake La Cruz (Spain). We observed in-situ photoferrotrophic activity through stimulation of phototrophic carbon uptake in the presence of Fe(II), and determined light-dependent Fe(II)-oxidation by the natural chemocline microbiota. Moreover, a photoferrotrophic bacterium most closely related to Chlorobium ferrooxidans was enriched from the ferruginous water column. Our study for the first time demonstrates a direct link between anoxygenic photoferrotrophy and the anoxic precipitation of Fe(III)-oxides in a ferruginous water column, providing a plausible mechanism for the bacterial origin of BIFs before the advent of free oxygen. However, photoferrotrophs represent only a minor fraction of the anoxygenic phototrophic community with the majority apparently thriving by sulfur cycling, despite the very low sulfur content in the ferruginous chemocline of Lake La Cruz.

  10. Thermal decomposition of pyrometallurgical copper slag by oxidation in synthetic air.

    Science.gov (United States)

    Gyurov, Stoyko; Kostova, Yoanna; Klitcheva, Galina; Ilinkina, Anna

    2011-02-01

    The purpose of this study was to investigate the possibility of separating pyrometallurgical copper (fayalite) slag by oxidation in a synthetic air atmosphere into ferrous and silicate phases suitable for resources to be recovered from them. Isothermal oxidation kinetics and the most probable reaction models are studied in the temperature range of 773 to 1173 K using thermogravimetric analysis data and the classical Johnson-Mehl-Avrami-Yerofeev-Kolmogorov (JMAYK) equation. Depending on the model applied, the activation energies of fayalite slag oxidation in the temperature range of 773-973 K were: D1: 37.55 kJ mol(-1); D2: 43.27 kJ mol(-1); D3: 50.52 kJ mol(-1); and D4: 45.65 kJ mol(-1). Depending on the model applied, the activation energies of fayalite slag oxidation in the temperature range of 1073-1173 K were: F1: 20.48 kJ mol(-1); R2: 20.45 kJ mol(-1); R3: 20.18 kJ mol(-1); A2: 21.54 kJ mol( -1) and A3: 22.34 kJ mol(-1). The transformation of fayalite to hematite and amorphous silica was completed after 1435, 1350 and 1080 s at temperatures of 1073, 1123 and 1173 K, respectively. The following oxidation products were identified by X-ray diffraction: (1) fayalite, hematite and magnesioferrite (Fe(2)MgO(4)) in the temperature range 773 to 973 K; and (2) hematite and magnesium iron oxide (Mg(1.55)Fe( 1.6)O(4)) in the temperature range of 1073 to 1173 K.

  11. The Enzymatic Oxidation of Graphene Oxide

    Science.gov (United States)

    Kotchey, Gregg P.; Allen, Brett L.; Vedala, Harindra; Yanamala, Naveena; Kapralov, Alexander A.; Tyurina, Yulia Y.; Klein-Seetharaman, Judith; Kagan, Valerian E.; Star, Alexander

    2011-01-01

    Two-dimensional graphitic carbon is a new material with many emerging applications, and studying its chemical properties is an important goal. Here, we reported a new phenomenon – the enzymatic oxidation of a single layer of graphitic carbon by horseradish peroxidase (HRP). In the presence of low concentrations of hydrogen peroxide (~40 µM), HRP catalyzed the oxidation of graphene oxide, which resulted in the formation of holes on its basal plane. During the same period of analysis, HRP failed to oxidize chemically reduced graphene oxide (RGO). The enzymatic oxidation was characterized by Raman, UV-Vis, EPR and FT-IR spectroscopy, TEM, AFM, SDS-PAGE, and GC-MS. Computational docking studies indicated that HRP was preferentially bound to the basal plane rather than the edge for both graphene oxide and RGO. Due to the more dynamic nature of HRP on graphene oxide, the heme active site of HRP was in closer proximity to graphene oxide compared to RGO, thereby facilitating the oxidation of the basal plane of graphene oxide. We also studied the electronic properties of the reduced intermediate product, holey reduced graphene oxide (hRGO), using field-effect transistor (FET) measurements. While RGO exhibited a V-shaped transfer characteristic similar to a single layer of graphene that was attributed to its zero band gap, hRGO demonstrated a p-type semiconducting behavior with a positive shift in the Dirac points. This p-type behavior rendered hRGO, which can be conceptualized as interconnected graphene nanoribbons, as a potentially attractive material for FET sensors. PMID:21344859

  12. Oxidation and Precipitation of Sulfide in Sewer Networks

    DEFF Research Database (Denmark)

    Nielsen, A. H.

    (Fe(II)) and precipitated subsequently with dissolved sulfide as ferrous sulfide (FeS). The ferrous sulfide precipitation was relatively fast, but not immediate. Despite the very low solubility of ferrous sulfide, initially present iron did not react completely with sulfide. This observation...... were studied in both wastewater and biofilms. Particular emphasis was on the importance of iron in the sulfur cycle. Iron is typically among the dominant metals in wastewater. The experiments showed that, ferric iron (Fe(III)) that was added to anaerobic wastewater was rapidly reduced to ferrous iron...... was probably explained by the presence of ligands in the wastewater, which reacted with the iron. The biofilm experiments showed that sulfide accumulated along with several metals in anaerobic biofilms as the result of metal sulfide precipitation. Particularly, zinc and cupper were important...

  13. Metabolic mechanisms of methanol/formaldehyde in isolated rat hepatocytes: carbonyl-metabolizing enzymes versus oxidative stress.

    Science.gov (United States)

    MacAllister, Stephanie L; Choi, Joanna; Dedina, Liana; O'Brien, Peter J

    2011-05-30

    Methanol (CH(3)OH), a common industrial solvent, is metabolized to toxic compounds by several enzymatic as well as free radical pathways. Identifying which process best enhances or prevents CH(3)OH-induced cytotoxicity could provide insight into the molecular basis for acute CH(3)OH-induced hepatoxicity. Metabolic pathways studied include those found in 1) an isolated hepatocyte system and 2) cell-free systems. Accelerated Cytotoxicity Mechanism Screening (ACMS) techniques demonstrated that CH(3)OH had little toxicity towards rat hepatocytes in 95% O(2), even at 2M concentration, whereas 50 mM was the estimated LC(50) (2h) in 1% O(2), estimated to be the physiological concentration in the centrilobular region of the liver and also the target region for ethanol toxicity. Cytotoxicity was attributed to increased NADH levels caused by CH(3)OH metabolism, catalyzed by ADH1, resulting in reductive stress, which reduced and released ferrous iron from Ferritin causing oxygen activation. A similar cytotoxic mechanism at 1% O(2) was previous found for ethanol. With 95% O(2), the addition of Fe(II)/H(2)O(2), at non-toxic concentrations were the most effective agents for increasing hepatocyte toxicity induced by 1M CH(3)OH, with a 3-fold increase in cytotoxicity and ROS formation. Iron chelators, desferoxamine, and NADH oxidizers and ATP generators, e.g. fructose, also protected hepatocytes and decreased ROS formation and cytotoxicity. Hepatocyte protein carbonylation induced by formaldehyde (HCHO) formation was also increased about 4-fold, when CH(3)OH was oxidized by the Fenton-like system, Fe(II)/H(2)O(2), and correlated with increased cytotoxicity. In a cell-free bovine serum albumin system, Fe(II)/H(2)O(2) also increased CH(3)OH oxidation as well as HCHO protein carbonylation. Nontoxic ferrous iron and a H(2)O(2) generating system increased HCHO-induced cytotoxicity and hepatocyte protein carbonylation. In addition, HCHO cytotoxicity was markedly increased by ADH1 and

  14. Nitric oxide supersensitivity

    DEFF Research Database (Denmark)

    Olesen, J; Iversen, Helle Klingenberg; Thomsen, L L

    1993-01-01

    Nitroglycerin, which may be regarded as a prodrug for nitric oxide, induces a mild to moderate headache in healthy subjects. In order to study whether migraine patients are more sensitive to nitric oxide than non-migrainous subjects, four different doses of intravenous nitroglycerin were given...... previously shown a similar supersensitivity to histamine which in human cerebral arteries activates endothelial H1 receptors and causes endothelial production of nitric oxide. Migraine patients are thus supersensitive to exogenous nitric oxide from nitroglycerin as well as to endothelially produced nitric...... oxide. It is suggested that nitric oxide may be partially or completely responsible for migraine pain....

  15. Influence of oxidizing or reducing agents on gastrointestinal absorption of U, Pu, Am, Cm and Pm by rats

    International Nuclear Information System (INIS)

    Sullivan, M.F.; Ruemmler, P.S.; Ryan, J.L.; Buschbom, R.L.

    1986-01-01

    Absorption of 233U, 238Pu, 241Am, and 244Cm from the gastrointestinal (GI) tract was measured in rats, fed ad libitum or fasted, that were gavaged with solutions containing ferric iron, ferrous iron, iron powder, quinhydrone or ascorbic acid. Absorption and retention of all of these actinides was increased substantially by fasting and by the addition of mild oxidizing agents, ferric iron and quinhydrone. In contrast, absorption and retention were decreased to below the fasted level by all the reducing agents except ascorbic acid, which caused diarrhea and an increase in absorption. Absorption of the lanthanide element 147Pm from the intestine of fasted rats was also increased by ferric iron. Some of these actinide elements are polyvalent and are, in some cases, known to be absorbed from the GI tract more readily in their higher oxidation states. This suggested an oxidation-reduction mechanism for the effect of fasting and the action of the chemical agents used. However, the improbability that either 241Am(III) 244Cm(III) or 147Pm is converted to a different oxidation state under these conditions makes that mechanism unlikely. Other explanations are suggested

  16. Population dynamics of iron-oxidizing communities in pilot plants for the treatment of acid mine waters

    Energy Technology Data Exchange (ETDEWEB)

    Elke Heinzel; Eberhard Janneck; Franz Glombitza; Michael Schlmann; Jana Seifert [TU Bergakademie Freiberg, Freiberg (Germany). Interdisciplinary Ecological Center

    2009-08-15

    The iron-oxidizing microbial community in two pilot plants for the treatment of acid mine water was monitored to investigate the influence of different process parameters such as pH, iron concentration, and retention time on the stability of the system to evaluate the applicability of this treatment technology on an industrial scale. The dynamics of the microbial populations were followed using T-RFLP (terminal restriction fragment length polymorphism) over a period of several months. For a more precise quantification, two TaqMan assays specific for the two prominent groups were developed and the relative abundance of these taxa in the iron-oxidizing community was verified by real-time PCR. The investigations revealed that the iron-oxidizing community was clearly dominated by two groups of Betaproteobacteria affiliated with the poorly known and not yet recognized species 'Ferrovum myxofaciens' and with strains related to Gallionella ferruginea, respectively. These taxa dominated the microbial community during the whole investigation period and accelerated the oxidation of ferrous iron despite the changing characteristics of mine waters flowing into the plants. Thus, it is assumed that the treatment technology can also be applied to other mine sites and that these organisms play a crucial role in such treatment systems. 32 refs., 4 figs. 1 tab.

  17. Population dynamics of iron-oxidizing communities in pilot plants for the treatment of acid mine waters.

    Science.gov (United States)

    Heinzel, Elke; Janneck, Eberhard; Glombitza, Franz; Schlömann, Michael; Seifert, Jana

    2009-08-15

    The iron-oxidizing microbial community in two pilot plants for the treatment of acid mine water was monitored to investigate the influence of different process parameters such as pH, iron concentration, and retention time on the stability of the system to evaluate the applicability of this treatment technology on an industrial scale. The dynamics of the microbial populations were followed using T-RFLP (terminal restriction fragment length polymorphism) over a period of several months. For a more precise quantification, two TaqMan assays specific for the two prominent groups were developed and the relative abundance of these taxa in the iron-oxidizing community was verified by real-time PCR. The investigations revealed that the iron-oxidizing community was clearly dominated by two groups of Betaproteobacteria affiliated with the poorly known and not yet recognized species "Ferrovum myxofaciens" and with strains related to Gallionella ferruginea, respectively. These taxa dominated the microbial community during the whole investigation period and accelerated the oxidation of ferrous iron despite the changing characteristics of mine waters flowing into the plants. Thus, it is assumed that the treatment technology can also be applied to other mine sites and that these organisms play a crucial role in such treatment systems.

  18. Zinc oxide overdose

    Science.gov (United States)

    Zinc oxide is an ingredient in many products. Some of these are certain creams and ointments used ... prevent or treat minor skin burns and irritation. Zinc oxide overdose occurs when someone eats one of ...

  19. Oxidative Stress in Neurodegeneration

    Directory of Open Access Journals (Sweden)

    Varsha Shukla

    2011-01-01

    Full Text Available It has been demonstrated that oxidative stress has a ubiquitous role in neurodegenerative diseases. Major source of oxidative stress due to reactive oxygen species (ROS is related to mitochondria as an endogenous source. Although there is ample evidence from tissues of patients with neurodegenerative disorders of morphological, biochemical, and molecular abnormalities in mitochondria, it is still not very clear whether the oxidative stress itself contributes to the onset of neurodegeneration or it is part of the neurodegenerative process as secondary manifestation. This paper begins with an overview of how oxidative stress occurs, discussing various oxidants and antioxidants, and role of oxidative stress in diseases in general. It highlights the role of oxidative stress in neurodegenerative diseases like Alzheimer's, Parkinson's, and Huntington's diseases and amyotrophic lateral sclerosis. The last part of the paper describes the role of oxidative stress causing deregulation of cyclin-dependent kinase 5 (Cdk5 hyperactivity associated with neurodegeneration.

  20. Importance of allochthonous and autochthonous dissolved organic matter in Fe(II) oxidation: A case study in Shizugawa Bay watershed, Japan.

    Science.gov (United States)

    Lee, Ying Ping; Fujii, Manabu; Kikuchi, Tetsuro; Natsuike, Masafumi; Ito, Hiroaki; Watanabe, Toru; Yoshimura, Chihiro

    2017-08-01

    Ferrous iron (Fe[II]) oxidation by dissolved oxygen was investigated in the Shizugawa Bay watershed with particular attention given to the effect of dissolved organic matter (DOM) properties on Fe(II) oxidation. To cover a wide spectrum of DOM composition, water samples were collected from various water sources including freshwater (e.g., river water and wastewater effluent) and coastal seawater. Measurement of nanomolar Fe(II) oxidation by using luminol chemiluminescence under dark, air-saturated conditions at 25 °C indicated that spatio-temporal variation of the second-order rate constant (6.7-74.5 M -1  s -1 ) was partially explained by the variation of the sample pH (7.5-8.6). However, at comparable pH values, the oxidation rates for freshwater were generally greater than those for coastal seawater. The substantial decline in oxidation rate constant after the removal of humic-type (allochthonous) DOM suggested that this hydrophobic DOM is a key factor that accelerates the Fe(II) oxidation in the freshwater samples. Observed lower oxidation rates for coastal seawater compared with freshwater and organic ligand-free seawater were likely associated with microbially derived autochthonous DOM, and the variation of Fe(II) oxidation at a fixed pH was best described by fluorescence index that represents the proportion of autochthonous and allochthonous DOM in natural waters. Consistently, Fe(II) oxidation was found to be slower in the presence of cellular exudates from phytoplankton. The present study highlighted the significant effect of DOM composition on the Fe(II) oxidation in inland and coastal waters. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Ferrous iron- and ammonium-rich diffuse vents support habitat-specific communities in a shallow hydrothermal field off the Basiluzzo Islet (Aeolian Volcanic Archipelago).

    Science.gov (United States)

    Bortoluzzi, G; Romeo, T; La Cono, V; La Spada, G; Smedile, F; Esposito, V; Sabatino, G; Di Bella, M; Canese, S; Scotti, G; Bo, M; Giuliano, L; Jones, D; Golyshin, P N; Yakimov, M M; Andaloro, F

    2017-09-01

    Ammonium- and Fe(II)-rich fluid flows, known from deep-sea hydrothermal systems, have been extensively studied in the last decades and are considered as sites with high microbial diversity and activity. Their shallow-submarine counterparts, despite their easier accessibility, have so far been under-investigated, and as a consequence, much less is known about microbial communities inhabiting these ecosystems. A field of shallow expulsion of hydrothermal fluids has been discovered at depths of 170-400 meters off the base of the Basiluzzo Islet (Aeolian Volcanic Archipelago, Southern Tyrrhenian Sea). This area consists predominantly of both actively diffusing and inactive 1-3 meters-high structures in the form of vertical pinnacles, steeples and mounds covered by a thick orange to brown crust deposits hosting rich benthic fauna. Integrated morphological, mineralogical, and geochemical analyses revealed that, above all, these crusts are formed by ferrihydrite-type Fe 3+ oxyhydroxides. Two cruises in 2013 allowed us to monitor and sampled this novel ecosystem, certainly interesting in terms of shallow-water iron-rich site. The main objective of this work was to characterize the composition of extant communities of iron microbial mats in relation to the environmental setting and the observed patterns of macrofaunal colonization. We demonstrated that iron-rich deposits contain complex and stratified microbial communities with a high proportion of prokaryotes akin to ammonium- and iron-oxidizing chemoautotrophs, belonging to Thaumarchaeota, Nitrospira, and Zetaproteobacteria. Colonizers of iron-rich mounds, while composed of the common macrobenthic grazers, predators, filter-feeders, and tube-dwellers with no representatives of vent endemic fauna, differed from the surrounding populations. Thus, it is very likely that reduced electron donors (Fe 2+ and NH 4 + ) are important energy sources in supporting primary production in microbial mats, which form a habitat

  2. In Haitian women and preschool children, iron absorption from wheat flour-based meals fortified with sodium iron EDTA is higher than that from meals fortified with ferrous fumarate, and is not affected by Helicobacter pylori infection in children.

    Science.gov (United States)

    Herter-Aeberli, Isabelle; Eliancy, Kerline; Rathon, Yanick; Loechl, Cornelia U; Marhône Pierre, Joseline; Zimmermann, Michael B

    2017-08-01

    Fe fortification of wheat flour was proposed in Haiti to combat Fe deficiency, but Fe bioavailability from fortificants has never been investigated in Haitian women or preschool children, two key target groups. We aimed to investigate the bioavailability of ferrous fumarate (FeFum), NaFeEDTA and their combination from fortified wheat flour. We recruited twenty-two healthy mother-child pairs in Port au Prince, Haiti, for an Fe-absorption study. We administered stable Fe isotopes as FeFum or NaFeEDTA individually in low-extraction wheat flour bread rolls consumed by all participants in a randomised, cross-over design. In a final, identical meal, consumed only by the women, FeFum+NaFeEDTA was administered. We measured Fe absorption by using erythrocyte incorporation of stable isotopes 14 d after consumption of each meal, and determined Fe status, inflammatory markers and Helicobacter pylori infection. Fe absorption (geometric mean was 9·24 (95 % CI 6·35, 13·44) and 9·26 (95 % CI 7·00, 12·31) from FeFum and 13·06 (95 % CI 9·23, 19·10) and 12·99 (95 % CI 9·18, 18·39) from NaFeEDTA in mothers and children, respectively (Pflour may be a preferable, cost-effective fortification strategy.

  3. Sputtered tin oxide and titanium oxide thin films as alternative transparent conductive oxides

    OpenAIRE

    Boltz, Janika

    2011-01-01

    Alternative transparent conductive oxides to tin doped indium oxide have been investigated. In this work, antimony doped tin oxide and niobium doped titanium oxide have been studied with the aim to prepare transparent and conductive films. Antimony doped tin oxide and niobium doped titanium oxide belong to different groups of oxides; tin oxide is a soft oxide, while titanium oxide is a hard oxide. Both oxides are isolating materials, in case the stoichiometry is SnO2 and TiO2. In order to ach...

  4. The oxidative pulverisation of mixed oxide fuels

    International Nuclear Information System (INIS)

    Rance, Peter; Beznosyuk, Vassily

    2005-01-01

    An investigation of the oxidation of mixed uranium-plutonium oxide (MOx) fuels containing from 5-30% plutonium (heavy metal basis) in air and oxygen atmospheres has been undertaken. MOx pellets prepared by a co-precipitation process were oxidised at temperatures from 600 to 1200degC, samples were reduced back to the MO 2 state and then re-oxidised. Weight changes were monitored during each procedure and the phases present in the products from each treatment were analysed using X-ray diffraction (XRD). Samples containing up to 10% Pu were oxidised sufficiently to cause pulverisation of the fuel matrix by a single oxidation treatment at 600degC whereas samples containing higher plutonium contents required a cycle of oxidation-reduction-oxidation cause them to become fragmented. XRD data suggests the formation of plutonium-rich and plutonium-lean grains during the reduction cycle and it is suggested that the oxidation of plutonium-lean grains during re-oxidation step is responsible for the break up of the pellets during this step. (author)

  5. Effect Of Oxidation Temperature And Oxidation Time On Thickness ...

    African Journals Online (AJOL)

    Investigation has been made concerning the effect of oxidation temperature and time on the thickness of copper (I) oxides solar cells prepared by thermal oxidation method. The samples were oxidized at different oxidation temperatures and time. The different oxidation temperatures and lengths of time ware employed in ...

  6. Hydrothermal synthesis of graphene oxide/multiwalled carbon nanotube/Fe3O4 ternary nanocomposite for removal of Cu (II) and methylene blue

    Science.gov (United States)

    Long, Zhihang; Zhan, Yingqing; Li, Fei; Wan, Xinyi; He, Yi; Hou, Chunyan; Hu, Hai

    2017-09-01

    In this work, highly activated graphene oxide/multiwalled carbon nanotube/Fe3O4 ternary nanocomposite adsorbent was prepared from a simple hydrothermal route by using ferrous sulfate as precursor. For this purpose, the graphene oxide/multiwalled carbon nanotube architectures were formed through the π-π attractions between them, followed by attaching Fe3O4 nanoparticles onto their surface. The structure and composition of as-prepared ternary nanocomposite were characterized by XRD, FTIR, XPS, SEM, TEM, Raman, TGA, and BET. It was found that the resultant porous graphene oxide/multiwalled carbon nanotube/Fe3O4 ternary nanocomposite with large surface area could effectively prevent the π-π stacking interactions between graphene oxide nanosheets and greatly improve sorption sites on the surfaces. Thus, owing to the unique ternary nanocomposite architecture and synergistic effect among various components, as-prepared ternary nanocomposite exhibited high separation efficiency when they were used to remove the Cu (II) and methylene blue from aqueous solutions. Furthermore, the adsorption isotherms of ternary nanocomposite structures for Cu (II) and methylene blue removal fitted the Langmuir isotherm model. This work demonstrated that the graphene oxide/multiwalled carbon nanotube/Fe3O4 ternary nanocomposite was promising as an efficient adsorbent for heavy metal ions and organic dye removal from wastewater in low concentration.

  7. Wet oxidation of quinoline

    DEFF Research Database (Denmark)

    Thomsen, A.B.; Kilen, H.H.

    1998-01-01

    The influence of oxygen pressure (0.4 and 2 MPa). reaction time (30 and 60 min) and temperature (260 and 280 degrees C) on the wet oxidation of quinoline has been studied. The dominant parameters for the decomposition of quinoline were oxygen pressure and reaction temperature. whereas the reaction...... time was less important within the range studied. Nitrifying bacteria were used to measure the inhibition from wet oxidative-treated samples to study the effect of the (wet oxidation) reaction conditions. Wet oxidation made quinoline more toxic to Nitrosomonas. This was observed for Nitrobacter as well....... The combined wet oxidation and biological treatment of reaction products resulted in 91% oxidation of the parent compound to CO2 and water. Following combined wet oxidation and biological treatment the sample showed low toxicity towards Nitrosomonas and no toxicity towards Nitrobacter. (C) 1998 Elsevier...

  8. Hepatoprotective Effects of Ixora parviflora Extract against Exhaustive Exercise-Induced Oxidative Stress in Mice

    Directory of Open Access Journals (Sweden)

    Chi-Chang Huang

    2013-09-01

    Full Text Available Ixora parviflora, a species of the Rubiaceae, is rich in polyphenols and flavonoids, and has been traditionally used as a folk medicine. An I. parviflora extract (IPE has great antioxidant activity in vitro, including a scavenging effect on superoxide radicals, reducing power, and ferrous ion-chelating ability. However, whether IPE is efficacious against oxidative damage in vivo is not known. The purpose of this study was to determine the protective effects of IPE treatment on hepatic oxidative stress and antioxidant defenses after exhaustive exercise in mice. Fifty male C57BL/6 mice (6 week old were randomly divided into five groups and designated a sedentary control with vehicle (C, and exhaustive exercise with vehicle (IPE0, low dosage (IPE10, medium dosage (IPE50 and high dosage (IPE100 of IPE at 0, 10, 50, and 100 mg/kg, respectively. After a single bout of exhaustive swimming exercise challenge, levels of blood ammonia and creatine kinase (CK, and hepatic superoxide dismutase (SOD protein expression, thiobarbituric acid-reactive substance (TBARS, and gp91phox, p22phox, and p47phox subunits of nicotinamide adenine dinucleotide phosphate (NADPH oxidase expressions in the IPE0 group were significantly affected compared to those of the C group, but they were all significantly inhibited by the IPE treatments. Results of the present in vivo study in mice indicate that I. parviflora extract possesses antioxidative and hepatoprotective potential following exhaustive exercise.

  9. Interaction between Mitochondrial Reactive Oxygen Species, Heme Oxygenase, and Nitric Oxide Synthase Stimulates Phagocytosis in Macrophages

    Directory of Open Access Journals (Sweden)

    Andrea Müllebner

    2018-01-01

    Full Text Available BackgroundMacrophages are cells of the innate immune system that populate every organ. They are required not only for defense against invading pathogens and tissue repair but also for maintenance of tissue homeostasis and iron homeostasis.AimThe aim of this study is to understand whether heme oxygenase (HO and nitric oxide synthase (NOS contribute to the regulation of nicotinamide adenine dinucleotide phosphate oxidase (NOX activity and phagocytosis, two key components of macrophage function.MethodsThis study was carried out using resting J774A.1 macrophages treated with hemin or vehicle. Activity of NOS, HO, or NOX was inhibited using specific inhibitors. Reactive oxygen species (ROS formation was determined by Amplex® red assay, and phagocytosis was measured using fluorescein isothiocyanate-labeled bacteria. In addition, we analyzed the fate of the intracellular heme by using electron spin resonance.ResultsWe show that both enzymes NOS and HO are essential for phagocytic activity of macrophages. NOS does not directly affect phagocytosis, but stimulates NOX activity via nitric oxide-triggered ROS production of mitochondria. Treatment of macrophages with hemin results in intracellular accumulation of ferrous heme and an inhibition of phagocytosis. In contrast to NOS, HO products, including carbon monoxide, neither clearly affect NOX activity nor clearly affect phagocytosis, but phagocytosis is accelerated by HO-mediated degradation of heme.ConclusionBoth enzymes contribute to the bactericidal activity of macrophages independently, by controlling different pathways.

  10. Decomposition of nitrotoluenes in wastewater by sonoelectrochemical and sonoelectro-Fenton oxidation.

    Science.gov (United States)

    Chen, Wen-Shing; Huang, Chi-Pin

    2014-03-01

    Oxidative degradation of dinitrotoluene (DNT) and 2,4,6-trinitrotoluene (TNT) in wastewater was conducted using electrochemical and electro-Fenton processes respectively, combined with ultrasonic irradiation, wherein a synergistic effect is observed. Experiments were carried out to elucidate the influence of various operating variables on the sonoelectrolytic behavior, such as electrode potential, sonoelectrolytic temperature, acidity of wastewater, oxygen dosage, and dosage of ferrous ions. It deserves to note that the nitrotoluene contaminants could be completely decomposed by sonoelectro-Fenton method, wherein hydrogen peroxide was in situ generated from cathodic reduction of oxygen, supplied partially by anodic oxidation of water. During the sonoelectrolytic process, in spite of existence of degassing phenomenon, the high yield of hydrogen peroxide was produced due to the significantly enhanced mass transfer rate of oxygen toward the cathode, caused by ultrasonic irradiation. Because higher removal efficiency of DNTs and TNT obtained at ambient conditions, it is believed that the sonoelectrolytic method is potentially applied to dispose wastewater from toluene nitration processes. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. High yield, facile aqueous synthesis and characterization of C18 functionalized iron oxide nanoparticles

    Science.gov (United States)

    Nair, Kishore Kumar; Kaur, Ranjeet; Iqbal, Nusrat; Hasan, Abshar; Alam, Samsul; Raza, S. K.

    2015-04-01

    The present study shows the synthesis of magnetite nanoparticles by co-precipitation method in three steps. The steps involve the precipitation of Fe3O4 nanoparticles followed by layer by layer functionalization with silica and tetraethoxy(octadyl)silane (C18). The prepared magnetite nanoparticles were investigated by SEM, TEM, XRD, FTIR and VSM. It was suggested that the intermediate iron oxide nanoparticles were formed by the competing processes of oxidation and crystal growth after decomposition of ferrous and ferric salts. The first step synthesized nanoparticles were of around 16 ± 4 nm, second step silica coating of 18 ± 3 nm and the final step C18 were of 56 ± 6 nm. The tetraethylorthosilicate hydrolyzed to form silicic acid which further polymerizes and thereby forms a layer of silica over magnetite nanoparticles. FTIR peaks at 2854 and 2921 cm-1 confirm the layering of C18 on silica encapsulated nanoparticles which corresponds to ˜CH2 and ˜(CH2)17CH3 carbon chain symmetric extension. The thickness of silica coating and C18 are 1.9 ± 0.3 nm and 38.6 ± 2.5 nm as confirmed from TEM size distribution curve. The saturation magnetism of magnetite, silica coated and C18 nanoparticles are 77.46, 74.53 and 68.76 emu g-1 respectively. Thus, Fe3O4, silica and C18 encapsulated magnetite nanoparticles were superparamagnetic.

  12. Post-treatment of anaerobic reactor effluent using coagulation/oxidation followed by double filtration.

    Science.gov (United States)

    Cavallini, Grasiele Soares; de Sousa Vidal, Carlos Magno; de Souza, Jeanette Beber; de Campos, Sandro Xavier

    2016-04-01

    This study evaluates the efficacy of a sanitary sewage treatment system, proposing post-treatment of the effluent generated by the upflow anaerobic sludge blanket UASB reactor, through a Fenton coagulation/oxidation ((ferric chloride (FC) or ferrous sulfate (FS) and peracetic acid (PAA)), followed by a double filtration system, composed of a gravel ascending drainage filter and a sand descending filter. Following the assessment of treatability, the system efficiency was evaluated using physicochemical and microbiological parameters. In all treatments performed in the pilot unit, total suspended solids (TSS) were completely removed, leading to a decrease in turbidity greater than 90% and close to 100% removal of total phosphorous. In the FC and PAA combination, the effluent was oxygenated prior to filtration, enabling a more significant removal of biochemical oxygen demand (BOD), which characterizes aerobic degradation even in a quick sand filter. The treatments carried out in the presence of the PAA oxidizing agent showed a more significant bleaching of the effluent. Concerning the microbiological parameters, the simultaneous use of PAA and FC contributed to the partial inactivation of the assessed microorganisms. A 65% recovery of the effluent was obtained with the proposed treatment system, considering the volume employed in filter backwashing.

  13. Photocatalytic degradation and photo-Fenton oxidation of Congo red dye pollutants in water using natural chromite—response surface optimization

    Science.gov (United States)

    Shaban, Mohamed; Abukhadra, Mostafa R.; Ibrahim, Suzan S.; Shahien, Mohamed. G.

    2017-12-01

    Refined natural Fe-chromite was characterized by XRD, FT-IR, reflected polarized microscope, XRF and UV spectrophotometer. Photocatalytic degradation and photo-Fenton oxidation of Congo red dye by Fe-chromite was investigated using 1 mL H2O2. The degradation of dye was studied as a function of illumination time, chromite mass, initial dye concentration, and pH. Fe-chromite acts as binary oxide system from chromium oxide and ferrous oxide. Thus, it exhibits photocatalytic properties under UV illumination and photo-Fenton oxidation after addition of H2O2. The degradation in the presence of H2O2 reached the equilibrium stage after 8 h (59.4%) but in the absence of H2O2 continued to 12 h (54.6%). Photocatalytic degradation results fitted well with zero, first order and second order kinetic model but it represented by second order rather than by the other models. While the photo-Fenton oxidation show medium fitting with the second order kinetic model only. The values of kinetic rate constants for the photo-Fenton oxidation were greater than those for the photocatalytic degradation. Thus, degradation of Congo red dye using chromite as catalyst is more efficient by photo-Fenton oxidation. Based on the response surface analysis, the predicted optimal conditions for maximum removal of Congo red dye by photocatalytic degradation (100%) were 12 mg/l, 0.14 g, 3, and 11 h for dye concentration, chromite mass, pH, and illumination time, respectively. Moreover, the optimum condition for photo-Fenton oxidation of dye (100%) is 13.5 mg/l, 0.10 g, 4, and 10 h, respectively.

  14. Extending the models for iron and sulfur oxidation in the extreme Acidophile Acidithiobacillus ferrooxidans

    Directory of Open Access Journals (Sweden)

    Holmes David S

    2009-08-01

    Full Text Available Abstract Background Acidithiobacillus ferrooxidans gains energy from the oxidation of ferrous iron and various reduced inorganic sulfur compounds at very acidic pH. Although an initial model for the electron pathways involved in iron oxidation has been developed, much less is known about the sulfur oxidation in this microorganism. In addition, what has been reported for both iron and sulfur oxidation has been derived from different A. ferrooxidans strains, some of which have not been phylogenetically characterized and some have been shown to be mixed cultures. It is necessary to provide models of iron and sulfur oxidation pathways within one strain of A. ferrooxidans in order to comprehend the full metabolic potential of the pangenome of the genus. Results Bioinformatic-based metabolic reconstruction supported by microarray transcript profiling and quantitative RT-PCR analysis predicts the involvement of a number of novel genes involved in iron and sulfur oxidation in A. ferrooxidans ATCC23270. These include for iron oxidation: cup (copper oxidase-like, ctaABT (heme biogenesis and insertion, nuoI and nuoK (NADH complex subunits, sdrA1 (a NADH complex accessory protein and atpB and atpE (ATP synthetase F0 subunits. The following new genes are predicted to be involved in reduced inorganic sulfur compounds oxidation: a gene cluster (rhd, tusA, dsrE, hdrC, hdrB, hdrA, orf2, hdrC, hdrB encoding three sulfurtransferases and a heterodisulfide reductase complex, sat potentially encoding an ATP sulfurylase and sdrA2 (an accessory NADH complex subunit. Two different regulatory components are predicted to be involved in the regulation of alternate electron transfer pathways: 1 a gene cluster (ctaRUS that contains a predicted iron responsive regulator of the Rrf2 family that is hypothesized to regulate cytochrome aa3 oxidase biogenesis and 2 a two component sensor-regulator of the RegB-RegA family that may respond to the redox state of the quinone pool

  15. Oxidation Resistant Graphite Studies

    Energy Technology Data Exchange (ETDEWEB)

    W. Windes; R. Smith

    2014-07-01

    The Very High Temperature Reactor (VHTR) Graphite Research and Development Program is investigating doped nuclear graphite grades exhibiting oxidation resistance. During a oxygen ingress accident the oxidation rates of the high temperature graphite core region would be extremely high resulting in significant structural damage to the core. Reducing the oxidation rate of the graphite core material would reduce the structural effects and keep the core integrity intact during any air-ingress accident. Oxidation testing of graphite doped with oxidation resistant material is being conducted to determine the extent of oxidation rate reduction. Nuclear grade graphite doped with varying levels of Boron-Carbide (B4C) was oxidized in air at nominal 740°C at 10/90% (air/He) and 100% air. The oxidation rates of the boronated and unboronated graphite grade were compared. With increasing boron-carbide content (up to 6 vol%) the oxidation rate was observed to have a 20 fold reduction from unboronated graphite. Visual inspection and uniformity of oxidation across the surface of the specimens were conducted. Future work to determine the remaining mechanical strength as well as graphite grades with SiC doped material are discussed.

  16. Efficient Low-pH Iron Removal by a Microbial Iron Oxide Mound Ecosystem at Scalp Level Run.

    Science.gov (United States)

    Grettenberger, Christen L; Pearce, Alexandra R; Bibby, Kyle J; Jones, Daniel S; Burgos, William D; Macalady, Jennifer L

    2017-04-01

    Acid mine drainage (AMD) is a major environmental problem affecting tens of thousands of kilometers of waterways worldwide. Passive bioremediation of AMD relies on microbial communities to oxidize and remove iron from the system; however, iron oxidation rates in AMD environments are highly variable among sites. At Scalp Level Run (Cambria County, PA), first-order iron oxidation rates are 10 times greater than at other coal-associated iron mounds in the Appalachians. We examined the bacterial community at Scalp Level Run to determine whether a unique community is responsible for the rapid iron oxidation rate. Despite strong geochemical gradients, including a >10-fold change in the concentration of ferrous iron from 57.3 mg/liter at the emergence to 2.5 mg/liter at the base of the coal tailings pile, the bacterial community composition was nearly constant with distance from the spring outflow. Scalp Level Run contains many of the same taxa present in other AMD sites, but the community is dominated by two strains of Ferrovum myxofaciens , a species that is associated with high rates of Fe(II) oxidation in laboratory studies. IMPORTANCE Acid mine drainage pollutes more than 19,300 km of rivers and streams and 72,000 ha of lakes worldwide. Remediation is frequently ineffective and costly, upwards of $100 billion globally and nearly $5 billion in Pennsylvania alone. Microbial Fe(II) oxidation is more efficient than abiotic Fe(II) oxidation at low pH (P. C. Singer and W. Stumm, Science 167:1121-1123, 1970, https://doi.org/10.1126/science.167.3921.1121). Therefore, AMD bioremediation could harness microbial Fe(II) oxidation to fuel more-cost-effective treatments. Advances will require a deeper understanding of the ecology of Fe(II)-oxidizing microbial communities and the factors that control their distribution and rates of Fe(II) oxidation. We investigated bacterial communities that inhabit an AMD site with rapid Fe(II) oxidation and found that they were dominated by two

  17. Antioxidant and micronutrient-rich milk formula reduces lead poisoning and related oxidative damage in lead-exposed mice.

    Science.gov (United States)

    Zhang, Yu; Li, Qingqing; Liu, Xiaojie; Zhu, Hui; Song, Aihua; Jiao, Jingjing

    2013-07-01

    Lead poisoning is a global environmental disease that induces lifelong adverse health effects. The effect of a milk formula consisting of antioxidant of bamboo leaves (AOB), vitamin C (Vc), calcium lactate (CaLac), ferrous sulfate (FeSO₄) and zinc sulfate (ZnSO₄) on the reduction of lead and lead-induced oxidative damage in lead-exposed mice was studied. The lead-reducing effect of milk formula was investigated via a 7-week toxicokinetics study and a tissue distribution level examination. The ameliorating effect of milk formula on lead-induced oxidative damage was investigated. Results demonstrated current milk formula could effectively reduce blood lead levels (BLLs) and lead distribution levels of liver, kidneys, thighbones and brain in mice based on metal ion-mediated antagonism and chelation mechanisms. This milk formula could not only protect lead-susceptible tissues against lead poisoning, but also maintain normal absorption and distribution of essential elements in vivo. Meanwhile, current milk formula could prevent the reduction of δ-aminolevulinic acid dehydratase (δ-ALAD) activity and enhancement of free erythrocyte protoporphyrins (FEP) levels in blood erythrocytes of mice. Also, this formula could indirectly protect blood cell membranes against lead-induced lipid peroxidation. We conclude that current optimized milk formula effectively reduces lead poisoning and lead-induced in vivo oxidative damage in lead-exposed mice. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Design of Magnetic Gelatine/Silica Nanocomposites by Nanoemulsification: Encapsulation versus in Situ Growth of Iron Oxide Colloids

    Directory of Open Access Journals (Sweden)

    Joachim Allouche

    2014-07-01

    Full Text Available The design of magnetic nanoparticles by incorporation of iron oxide colloids within gelatine/silica hybrid nanoparticles has been performed for the first time through a nanoemulsion route using the encapsulation of pre-formed magnetite nanocrystals and the in situ precipitation of ferrous/ferric ions. The first method leads to bi-continuous hybrid nanocomposites containing a limited amount of well-dispersed magnetite colloids. In contrast, the second approach allows the formation of gelatine-silica core-shell nanostructures incorporating larger amounts of agglomerated iron oxide colloids. Both magnetic nanocomposites exhibit similar superparamagnetic behaviors. Whereas nanocomposites obtained via an in situ approach show a strong tendency to aggregate in solution, the encapsulation route allows further surface modification of the magnetic nanocomposites, leading to quaternary gold/iron oxide/silica/gelatine nanoparticles. Hence, such a first-time rational combination of nano-emulsion, nanocrystallization and sol-gel chemistry allows the elaboration of multi-component functional nanomaterials. This constitutes a step forward in the design of more complex bio-nanoplatforms.

  19. Effect of ultrasonic waves on the water turbidity during the oxidation of phenol. Formation of (hydro)peroxo complexes.

    Science.gov (United States)

    Villota, Natalia; Lomas, Jose M; Camarero, Luis M

    2017-11-01

    Analysis of the kinetics of aqueous phenol oxidation by a sono-Fenton process reveals that the via involving ortho-substituted intermediates prevails: catechol (25.0%), hydroquinone (7.7%) and resorcinol (0.6%). During the oxidation, water rapidly acquires color that reaches its maximum intensity at the maximum concentration of p-benzoquinone. Turbidity formation occurs at a slower rate. Oxidant dosage determines the nature of the intermediates, being trihydroxylated benzenes (pyrogallol, hydroxyhydroquinone) and muconic acid the main precursors causing turbidity. It is found that the concentration of iron species and ultrasonic waves affects the intensity of the turbidity. The pathway of (hydro)peroxo-iron(II) complexes formation is proposed. Operating with 20.0-27.8mgFe 2+ /kW rates leads to formation of (hydro)peroxo-iron(II) complexes, which induce high turbidity levels. These species would dissociate into ZZ-muconic acid and ferrous ions. Applying relationships around 13.9mgFe 2+ /kW, the formation of (hydro)peroxo-iron(III) complexes would occur, which could react with carboxylic acids (2,5-dioxo-3-hexenedioic acid). That reaction induces turbidity slower. This is due to the organic substrate reacting with two molecules of the (hydro)peroxo complex. Therefore, it is necessary to accelerate the iron regeneration, intensifying the ultrasonic irradiation. Afterwards, this complex would dissociate into maleic acid and ferric ions. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Degradation of polycyclic aromatic hydrocarbons by combined chemical pre-oxidation and bioremediation in creosote contaminated soil.

    Science.gov (United States)

    Kulik, Niina; Goi, Anna; Trapido, Marina; Tuhkanen, Tuula

    2006-03-01

    The ability of pre-oxidation to overcome polycyclic aromatic hydrocarbons (PAH) recalcitrance to biodegradation was investigated in creosote contaminated soil. Sand and peat artificially spiked with creosote (quality WEI C) were used as model systems. Ozonation and Fenton-like treatment were proved to be feasible technologies for PAH degradation in soil. The efficiency of ozonation was strongly dependent on the water content of treated soil samples. The removal of PAH by Fenton-like treatment depended on the applied H2O2/soil weight ratio and ferrous ions addition. It was determined that the application of chemical oxidation in sand resulted in a higher PAH removal and required lower oxidant (ozone, hydrogen peroxide) doses. The enhancement of PAH biodegradability by different pre-treatment technologies also depended on the soil matrix. It was ascertained that combined chemical and biological treatment was more efficient in PAH elimination in creosote contaminated soil than either one alone. Thus, the combination of Fenton-like and the subsequent biological treatment resulted in the highest removal of PAH in creosote contaminated sand, and biodegradation with pre-ozonation was found to be the most effective technology for PAH elimination in peat.

  1. Degradation of polycyclic aromatic hydrocarbons by combined chemical pre-oxidation and bioremediation in creosote contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Niina Kulik; Anna Goi; Marina Trapido; Tuula Tuhkanen [Tallinn University of Technology, Tallinn (Estonia). Department of Chemical Engineering

    2006-03-15

    The ability of pre-oxidation to overcome polycyclic aromatic hydrocarbons (PAH) recalcitrance to biodegradation was investigated in creosote contaminated soil. Sand and peat artificially spiked with creosote (quality WEI C) were used as model systems. Ozonation and Fenton-like treatment were proved to be feasible technologies for PAH degradation in soil. The efficiency of ozonation was strongly dependent on the water content of treated soil samples. The removal of PAH by Fenton-like treatment depended on the applied H{sub 2}O{sub 2}/soil weight ratio and ferrous ions addition. It was determined that the application of chemical oxidation in sand resulted in a higher PAH removal and required lower oxidant (ozone, hydrogen peroxide) doses. The enhancement of PAH biodegradability by different pre-treatment technologies also depended on the soil matrix. It was ascertained that combined chemical and biological treatment was more efficient in PAH elimination in creosote contaminated soil than either one alone. Thus, the combination of Fenton-like and the subsequent biological treatment resulted in the highest removal of PAH in creosote contaminated sand, and biodegradation with pre-ozonation was found to be the most effective technology for PAH elimination in peat.

  2. Biomimetic Water-Oxidation Catalysts: Manganese Oxides.

    Science.gov (United States)

    Kurz, Philipp

    2016-01-01

    The catalytic oxidation of water to molecular oxygen is a key process for the production of solar fuels. Inspired by the biological manganese-based active site for this reaction in the enzyme Photosystem II, researchers have made impressive progress in the last decades regarding the development of synthetic manganese catalysts for water oxidation. For this, it has been especially fruitful to explore the many different types of known manganese oxides MnOx. This chapter first offers an overview of the structural, thermodynamic, and mechanistic aspects of water-oxidation catalysis by MnOx. The different test systems used for catalytic studies are then presented together with general reactivity trends. As a result, it has been possible to identify layered, mixed Mn (III/IV)-oxides as an especially promising class of bio-inspired catalysts and an attempt is made to give structure-based reasons for the good performances of these materials. In the outlook, the challenges of catalyst screenings (and hence the identification of a "best MnOx catalyst") are discussed. There is a great variety of reaction conditions which might be relevant for the application of manganese oxide catalysts in technological solar fuel-producing devices, and thus catalyst improvements are currently still addressing a very large parameter space. Nonetheless, detailed knowledge about the biological catalyst and a solid experimental basis concerning the syntheses and water-oxidation reactivities of MnOx materials have been established in the last decade and thus this research field is well positioned to make important contributions to solar fuel research in the future.

  3. Barium oxide, calcium oxide, magnesia, and alkali oxide free glass

    Science.gov (United States)

    Lu, Peizhen Kathy; Mahapatra, Manoj Kumar

    2013-09-24

    A glass composition consisting essentially of about 10-45 mole percent of SrO; about 35-75 mole percent SiO.sub.2; one or more compounds from the group of compounds consisting of La.sub.2O.sub.3, Al.sub.2O.sub.3, B.sub.2O.sub.3, and Ni; the La.sub.2O.sub.3 less than about 20 mole percent; the Al.sub.2O.sub.3 less than about 25 mole percent; the B.sub.2O.sub.3 less than about 15 mole percent; and the Ni less than about 5 mole percent. Preferably, the glass is substantially free of barium oxide, calcium oxide, magnesia, and alkali oxide. Preferably, the glass is used as a seal in a solid oxide fuel/electrolyzer cell (SOFC) stack. The SOFC stack comprises a plurality of SOFCs connected by one or more interconnect and manifold materials and sealed by the glass. Preferably, each SOFC comprises an anode, a cathode, and a solid electrolyte.

  4. Oxidizer Scoping Studies

    Energy Technology Data Exchange (ETDEWEB)

    Chancellor, Christopher John [Los Alamos National Laboratory

    2016-11-07

    The purpose of this report is to present the results of the acceptable knowledge (AK) review of oxidizers present in active waste streams, provide a technical analysis of the oxidizers, and report the results of the scoping study testing. This report will determine the fastest burning oxidizer to be used in the development of a Test Plan for Preparation and Testing of Sorbents Mixed with Oxidizer found in Transuranic Waste (DWT-TP-001). The companion report, DWT-RPT-002, Sorbent Scoping Studies, contains similar information for sorbents identified during the AK review of TRU waste streams. The results of the oxidizer and sorbent scoping studies will be used to inform the QL1 test plan. The QL1 test results will support the development of a basis of knowledge document that will evaluate oxidizing chemicals and sorbents in TRU waste and provide guidance for treatment.

  5. METAL OXIDE NANOPARTICLES

    Energy Technology Data Exchange (ETDEWEB)

    FERNANDEZ-GARCIA,M.; RODGRIGUEZ, J.A.

    2007-10-01

    This chapter covers the fundamental science, synthesis, characterization, physicochemical properties and applications of oxide nanomaterials. Explains fundamental aspects that determine the growth and behavior of these systems, briefly examines synthetic procedures using bottom-up and top-down fabrication technologies, discusses the sophisticated experimental techniques and state of the art theory results used to characterize the physico-chemical properties of oxide solids and describe the current knowledge concerning key oxide materials with important technological applications.

  6. Efetividade de três esquemas com sulfato ferroso para tratamento de anemia em gestantes The effectiveness of three regimens using ferrous sulfate to treat anemia in pregnant women

    Directory of Open Access Journals (Sweden)

    Ariani Impieri de Souza

    2004-05-01

    Full Text Available OBJETIVO: Avaliar a efetividade de três esquemas de tratamento utilizando sulfato ferroso em gestantes anêmicas. MÉTODOS: O estudo foi desenvolvido no Centro de Atenção à Mulher do Instituto Materno Infantil de Pernambuco, em Recife, no período de maio de 2000 a dezembro de 2001. Realizou-se um ensaio clínico, aleatório e cego do ponto de vista laboratorial, utilizando comprimidos de 300 mg de sulfato ferroso para administração de 60 mg de ferro elementar. As gestantes foram alocadas em três grupos de tratamento, conforme a freqüência de administração do ferro: uma vez por semana (n =48; duas vezes por semana (n =53; e uma vez ao dia (n =49. Foram comparadas as concentrações de hemoglobina, volume corpuscular médio e ferritina. RESULTADOS: Antes da intervenção, os grupos eram homogêneos e apresentaram as seguintes médias e desvios-padrão nas concentrações de hemoglobina: 10,2 ± 0,5 g/dL para o grupo que recebeu sulfato ferroso uma vez por semana; 10,2 ± 0,6 g/dL para o grupo que recebeu sulfato ferroso duas vezes por semana; e 10,1 ± 0,6 g/dL para o grupo que recebeu sulfato ferroso uma vez ao dia. As médias de volume corpuscular médio foram, respectivamente: 88,5 ± 5,0; 87,6 ± 5,9; e 88,7 ± 5,1 fL. As medianas de ferritina foram 30,2; 37,1; e 52,9 ng/mL. Houve 27% de cura no esquema de uma vez por semana, 34% no grupo tratado duas vezes por semana e 47% no tratamento diário. Houve fracasso terapêutico (hemoglobina OBJECTIVE: To evaluate the effectiveness of three regimens employing ferrous sulfate to treat pregnant women with anemia. METHODS: The study was carried out at the Women's Health Center of the Pernambuco Institute of Maternal and Child Health in the city of Recife, Pernambuco, Brazil, from May 2000 to December 2001. A randomized clinical trial with blinded laboratory analysis was conducted. Iron (60 mg was administered as 300-mg ferrous sulfate tablets. The women were allocated to three treatment

  7. Molecular water oxidation catalysis

    CERN Document Server

    Llobet, Antoni

    2014-01-01

    Photocatalytic water splitting is a promising strategy for capturing energy from the sun by coupling light harvesting and the oxidation of water, in order to create clean hydrogen fuel. Thus a deep knowledge of the water oxidation catalysis field is essential to be able to come up with useful energy conversion devices based on sunlight and water splitting. Molecular Water Oxidation Catalysis: A Key Topic for New Sustainable Energy Conversion Schemes presents a comprehensive and state-of-the-art overview of water oxidation catalysis in homogeneous phase, describing in detail the most importan

  8. Magnetic hyperthermia in phosphate coated iron oxide nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Lahiri, B.B.; Muthukumaran, T.; Philip, John, E-mail: philip@igcar.gov.in

    2016-06-01

    We study the magnetic field induced hyperthermia in water based phosphate coated Fe{sub 3}O{sub 4} nanofluids, synthesized by a co-precipitation method using ferrous and ferric salt solutions, ammonia and orthophosphoric acid. The specific absorption rate (SAR) values were measured at a fixed frequency of 126 kHz and at extremely low field amplitudes. The SAR values were determined from the initial rate of temperature rise curves under non-adiabatic conditions. It was observed that the SAR initially increases with sample concentration, attains a maximum at an optimum concentration and beyond which SAR decreases. The decrease in SAR values beyond the optimum concentration was attributed to the enhancement of dipolar interaction and agglomeration of the particles. The system independent intrinsic loss power (ILP) values, obtained by normalizing the SAR values with respect to field amplitude and frequency, were found to vary between 158–125 nHm{sup 2} kg{sup −1}, which were the highest benchmark values reported in the biologically safe experimental limit of 1.03–0.92×10{sup 8} Am{sup −1} s{sup −1}. The very high value of ILP observed in the bio-compatible phosphate coated iron oxide nanofluids may find practical applications for these nanoparticles in tumor targeted hyperthermia treatment. - Highlights: • Magnetic field induced hyperthermia of phosphate coated Fe{sub 3}O{sub 4} nanofluid is studied. • Phosphate coated Fe{sub 3}O{sub 4} are synthesized using a single step co-precipitation method. • SAR increases with concentration up to 2 wt% and then decreases. • Decrease in SAR values was due to stronger dipolar interaction and agglomeration. • The normalized SAR values ranges between 158–125 nHm{sup 2} kg{sup −1}.

  9. Novel RGO/α-FeOOH supported catalyst for Fenton oxidation of phenol at a wide pH range using solar-light-driven irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ying, E-mail: yingwang@bnu.edu.cn [The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875 (China); Fang, Jiasheng, E-mail: fangfangcanfly@163.com [The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875 (China); School of Chemistry and Chemical Engineering, Southeast University, Jiangsu Optoelectronic Functional Materials and Engineering Laboratory, Nanjing 211189 (China); Crittenden, John C., E-mail: John.Crittenden@ce.gatech.edu [School of Civil and Environmental Engineering and the Brook Byers Institute for Sustainable Systems, Georgia Institute of Technology, Atlanta, GA 30332-0595 (United States); Shen, Chanchan [The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875 (China)

    2017-05-05

    Graphical abstract: Schematic of the preparation of RF supported catalysts and the reaction mechanism for SLD Fenton catalytic degradation of aqueous phenol. - Highlights: • Novel SLD Fenton catalyst was synthesized via in-situ induced self-assembly process. • RGO improved light-harvesting capacity and enhanced electro-transport performance. • Visible light irradiation accelerated reaction and extended operating pHs (4.0–8.0). • H{sub 2}O{sub 2} reduction and H{sub 2}O oxidation yielded ·OH in Fe{sup Ⅱ}/Fe{sup Ⅲ} and Fe{sup Ⅲ}/Fe{sup Ⅳ} cycling process. - Abstract: A novel solar-light-driven (SLD) Fenton catalyst was developed by reducing the ferrous-ion onto graphene oxide (GO) and forming reduced graphene oxide/α-FeOOH composites (RF) via in-situ induced self-assembly process. The RF was supported on several mesoporous supports (i.e., Al-MCM-41, MCM-41 and γ-Al{sub 2}O{sub 3}). The activity, stability and energy use for phenol oxidation were systematically studied for a wide pH range. Furthermore, the catalytic mechanism at acid and alkaline aqueous conditions was also elucidated. The results showed that Fe(II) was reduced onto GO nanosheets and α-FeOOH crystals were formed during the self-assembly process. Compared with Fenton reaction without SLD irradiation, the visible light irradiation not only dramatically accelerated the rate of Fenton-based reactions, but also extended the operating pH for the Fenton reaction (from 4.0 to 8.0). The phenol oxidation on RF supported catalysts was fitting well with the pseudo-first-order kinetics, and needed low initiating energy, insensitive to the reacting temperature changes (273–318 K). The Al-MCM-41 supported RF was a more highly energy-efficient catalyst with the prominent catalytic activity at wide operating pHs. During the reaction, ·OH radicals were generated by the SLD irradiation from H{sub 2}O{sub 2} reduction and H{sub 2}O oxidation in the Fe{sup Ⅱ}/Fe{sup Ⅲ} and Fe{sup Ⅲ}/Fe{sup

  10. Minerals Masquerading As Enzymes: Abiotic Oxidation Of Soil Organic Matter In An Iron-Rich Humid Tropical Forest Soil

    Science.gov (United States)

    Hall, S. J.; Silver, W. L.

    2010-12-01

    Oxidative reactions play an important role in decomposing soil organic matter fractions that resist hydrolytic degradation, and fundamentally affect the cycling of recalcitrant soil carbon across ecosystems. Microbial extracellular oxidative enzymes (e.g. lignin peroxidases and laccases) have been assumed to provide a dominant role in catalyzing soil organic matter oxidation, while other potential oxidative mechanisms remain poorly explored. Here, we show that abiotic reactions mediated by the oxidation of ferrous iron (Fe(II)) could explain high potential oxidation rates in humid tropical forest soils, which often contain high concentrations of Fe(II) and experience rapid redox fluctuations between anaerobic and aerobic conditions. These abiotic reactions could provide an additional mechanism to explain high rates of decomposition in these ecosystems, despite frequent oxygen deficits. We sampled humid tropical forest soils in Puerto Rico, USA from various topographic positions, ranging from well-drained ridges to riparian valleys that experience broad fluctuations in redox potential. We measured oxidative activity by adding the model humic compound L-DOPA to soil slurries, followed by colorimetric measurements of the supernatant solution over time. Dilute hydrogen peroxide was added to a subset of slurries to measure peroxidative activity. We found that oxidative and peroxidative activity correlated positively with soil Fe(II) concentrations, counter to prevailing theory that low redox potential should suppress oxidative enzymes. Boiling or autoclaving sub-samples of soil slurries to denature any enzymes present typically increased peroxidative activity and did not eliminate oxidative activity, further suggesting the importance of an abiotic mechanism. We found substantial differences in the oxidation products of the L-DOPA substrate generated by our soil slurries in comparison with oxidation products generated by a purified enzyme (mushroom tyrosinase

  11. Cosmological billiards and oxidation

    International Nuclear Information System (INIS)

    De Buyl, S.; Paulot, L.; Henneaux, M.; Julia, B.

    2004-01-01

    We show how the properties of the cosmological billiards provide useful information (spacetime dimension and p-form spectrum) on the oxidation endpoint of the oxidation sequence of gravitational theories. We compare this approach to the other available methods: GL(n,R) subgroups and the superalgebras of dualities. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  12. Catalyst for Ammonia Oxidation

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a bimetallic catalyst for ammonia oxidation, a method for producing a bimetallic catalyst for ammonia oxidation and a method for tuning the catalytic activity of a transition metal. By depositing an overlayer of less catalytic active metal onto a more catalytic...

  13. Monolithic metal oxide transistors.

    Science.gov (United States)

    Choi, Yongsuk; Park, Won-Yeong; Kang, Moon Sung; Yi, Gi-Ra; Lee, Jun-Young; Kim, Yong-Hoon; Cho, Jeong Ho

    2015-04-28

    We devised a simple transparent metal oxide thin film transistor architecture composed of only two component materials, an amorphous metal oxide and ion gel gate dielectric, which could be entirely assembled using room-temperature processes on a plastic substrate. The geometry cleverly takes advantage of the unique characteristics of the two components. An oxide layer is metallized upon exposure to plasma, leading to the formation of a monolithic source-channel-drain oxide layer, and the ion gel gate dielectric is used to gate the transistor channel effectively at low voltages through a coplanar gate. We confirmed that the method is generally applicable to a variety of sol-gel-processed amorphous metal oxides, including indium oxide, indium zinc oxide, and indium gallium zinc oxide. An inverter NOT logic device was assembled using the resulting devices as a proof of concept demonstration of the applicability of the devices to logic circuits. The favorable characteristics of these devices, including (i) the simplicity of the device structure with only two components, (ii) the benign fabrication processes at room temperature, (iii) the low-voltage operation under 2 V, and (iv) the excellent and stable electrical performances, together support the application of these devices to low-cost portable gadgets, i.e., cheap electronics.

  14. Death from Nitrous Oxide.

    Science.gov (United States)

    Bäckström, Björn; Johansson, Bengt; Eriksson, Anders

    2015-11-01

    Nitrous oxide is an inflammable gas that gives no smell or taste. It has a history of abuse as long as its clinical use, and deaths, although rare, have been reported. We describe two cases of accidental deaths related to voluntary inhalation of nitrous oxide, both found dead with a gas mask covering the face. In an attempt to find an explanation to why the victims did not react properly to oncoming hypoxia, we performed experiments where a test person was allowed to breath in a closed system, with or without nitrous oxide added. Vital signs and gas concentrations as well as subjective symptoms were recorded. The experiments indicated that the explanation to the fact that neither of the descendents had reacted to oncoming hypoxia and hypercapnia was due to the inhalation of nitrous oxide. This study raises the question whether nitrous oxide really should be easily, commercially available. © 2015 American Academy of Forensic Sciences.

  15. Protein oxidation in aquatic foods

    DEFF Research Database (Denmark)

    Baron, Caroline P.

    2014-01-01

    The chapter discusses general considerations about protein oxidation and reviews the mechanisms involved in protein oxidation and consequences of protein oxidation on fish proteins. It presents two case studies, the first deals with protein and lipid oxidation in frozen rainbow trout......, and the second with oxidation in salted herring. The mechanisms responsible for initiation of protein oxidation are unclear, but it is generally accepted that free radical species initiating lipid oxidation can also initiate protein oxidation. The chapter focuses on interaction between protein and lipid...... oxidation. The protein carbonyl group measurement is the widely used method for estimating protein oxidation in foods and has been used in fish muscle. The chapter also talks about the impact of protein oxidation on protein functionality, fish muscle texture, and food nutritional value. Protein oxidation...

  16. Antioxidant effects of extracts from Cassia tora L. prepared under different degrees of roasting on the oxidative damage to biomolecules.

    Science.gov (United States)

    Yen, G C; Chung, D Y

    1999-04-01

    The effects of water extracts from Cassia tora L. (WECT) treated with different degrees of roasting (unroasted and roasted at 150, 200, and 250 degrees C) on the oxidative damage to deoxyribose, DNA, and DNA base in vitro were investigated. It was found that WECT alone induced a slight strand breaking of DNA. In the presence of Fe(3+)/H(2)O(2), WECT accelerated the strand breaking of DNA at a concentration of 2 microg/mL; however, it decreased with increasing concentrations (>5 microg/mL) of WECT. WECT also accelerated the oxidation of deoxyribose induced by Fe(3+)-EDTA/H(2)O(2) at a concentration of 0.2 mg/mL but inhibited the oxidation of deoxyribose induced by Fe(3+)-EDTA/H(2)O(2)/ascorbic acid. Furthermore, WECT accelerated the oxidation of 2'-deoxyguanosine (2'-dG) to form 8-OH-2'-dG induced by Fe(3+)-EDTA/H(2)O(2). The prooxidant action of WECT on the oxidation of 2'-dG was in the order of unroasted > roasted at 150 degrees C > roasted at 200 degrees C > roasted at 250 degrees C. The decrease in the prooxidant activity of the roasted sample might be due to the reduction in its anthraquinone glycoside content or the formation of antioxidant Maillard reaction products after roasting. Thus, WECT exhibited either a prooxidant or an antioxidant property in the model system that was dependent on the activities of the reducing metal ions, scavenging hydroxyl radical, and chelating ferrous ion.

  17. Quantitative evaluation of the effect of H2O degassing on the oxidation state of magmas

    Science.gov (United States)

    Lange, R. A.; Waters, L.

    2014-12-01

    The extent to which degassing of the H2O component affects the oxidation state of hydrous magmas is widely debated. Several researchers have examined how degassing of mixed H-C-O-S-Cl fluids may change the Fe3+/FeT ratio of various magmas, whereas our focus is on the H2O component. There are two ways that degassing of H2O by itself may cause oxidation: (1) the reaction: H2O (melt) + 2FeO (melt) = H2 (fluid) + Fe2O3 (melt), and/or (2) if dissolved water preferentially enhances the activity of ferrous vs. ferric iron in magmatic liquids. In this study, a comparison is made between the pre-eruptive oxidation states of 14 crystal-poor, jet-black obsidian samples (obtained from two Fe-Ti oxides) and their post-eruptive values (analyzed with the Wilson 1960 titration method tested against USGS standards). The obsidians are from Medicine Lake (CA), Long Valley (CA), and the western Mexican arc; all have low FeOT (1.1-2.1 wt%), rendering their Fe2+/Fe3+ ratios highly sensitive to the possible effects of substantial H2O degassing. The Fe-Ti oxide thermometer/oxybarometer of Ghiorso and Evans, (2008) gave temperatures for the 14 samples that range for 720 to 940°C and ΔNNO values of -0.9 to +1.4. With temperature known, the plagioclase-liquid hygrometer was applied and show that ≤ 6.5 wt% H2O was dissolved in the melts prior to eruption. In addition, pre-eruptive Cl and S concentrations were constrained on the basis of apatite analyses (Webster et al., 2009) and sulfur concentrations needed for saturation with pyrrhotite (Clemente et al., 2004), respectively. Maximum pre-eruptive chlorine and sulfur contents are 6000 and 200 ppm, respectively. After eruption, the rhyolites lost nearly all of their volatiles. Our results indicate no detectable change between pre- and post-eruptive Fe2+ concentrations, with an average deviation of ± 0.1 wt % FeO. Although degassing of large concentrations of S and/or Cl may affect the oxidation state of magmas, at the pre-eruptive levels

  18. Physiological Levels of Nitric Oxide Diminish Mitochondrial Superoxide. Potential Role of Mitochondrial Dinitrosyl Iron Complexes and Nitrosothiols

    Directory of Open Access Journals (Sweden)

    Sergey I. Dikalov

    2017-11-01

    Full Text Available Mitochondria are the major source of superoxide radicals and superoxide overproduction contributes to cardiovascular diseases and metabolic disorders. Endothelial dysfunction and diminished nitric oxide levels are early steps in the development of these pathological conditions. It is known that physiological production of nitric oxide reduces oxidative stress and inflammation, however, the precise mechanism of “antioxidant” effect of nitric oxide is not clear. In this work we tested the hypothesis that physiological levels of nitric oxide diminish mitochondrial superoxide production without inhibition of mitochondrial respiration. In order to test this hypothesis we analyzed effect of low physiological fluxes of nitric oxide (20 nM/min on superoxide and hydrogen peroxide production by ESR spin probes and Amplex Red in isolated rat brain mitochondria. Indeed, low levels of nitric oxide substantially attenuated both basal and antimycin A-stimulated production of reactive oxygen species in the presence of succinate or glutamate/malate as mitochondrial substrates. Furthermore, slow releasing NO donor DPTA-NONOate (100 μM did not change oxygen consumption in State 4 and State 3. However, the NO-donor strongly inhibited oxygen consumption in the presence of uncoupling agent CCCP, which is likely associated with inhibition of the over-reduced complex IV in uncoupled mitochondria. We have examined accumulation of dinitrosyl iron complexes and nitrosothiols in mitochondria treated with fast-releasing NO donor MAHMA NONOate (10 μM for 30 min until complete release of NO. Following treatment with NO donor, mitochondria were frozen for direct detection of dinitrosyl iron complexes using Electron Spin Resonance (ESR while accumulation of nitrosothiols was measured by ferrous-N-Methyl-D-glucamine dithiocarbamate complex, Fe(MGD2, in lysed mitochondria. Treatment of mitochondria with NO-donor gave rise to ESR signal of dinitrosyl iron complexes while ESR

  19. Oxide Nanocrystal Model Catalysts.

    Science.gov (United States)

    Huang, Weixin

    2016-03-15

    Model catalysts with uniform and well-defined surface structures have been extensively employed to explore structure-property relationships of powder catalysts. Traditional oxide model catalysts are based on oxide single crystals and single crystal thin films, and the surface chemistry and catalysis are studied under ultrahigh-vacuum conditions. However, the acquired fundamental understandings often suffer from the "materials gap" and "pressure gap" when they are extended to the real world of powder catalysts working at atmospheric or higher pressures. Recent advances in colloidal synthesis have realized controlled synthesis of catalytic oxide nanocrystals with uniform and well-defined morphologies. These oxide nanocrystals consist of a novel type of oxide model catalyst whose surface chemistry and catalysis can be studied under the same conditions as working oxide catalysts. In this Account, the emerging concept of oxide nanocrystal model catalysts is demonstrated using our investigations of surface chemistry and catalysis of uniform and well-defined cuprous oxide nanocrystals and ceria nanocrystals. Cu2O cubes enclosed with the {100} crystal planes, Cu2O octahedra enclosed with the {111} crystal planes, and Cu2O rhombic dodecahedra enclosed with the {110} crystal planes exhibit distinct morphology-dependent surface reactivities and catalytic properties that can be well correlated with the surface compositions and structures of exposed crystal planes. Among these types of Cu2O nanocrystals, the octahedra are most reactive and catalytically active due to the presence of coordination-unsaturated (1-fold-coordinated) Cu on the exposed {111} crystal planes. The crystal-plane-controlled surface restructuring and catalytic activity of Cu2O nanocrystals were observed in CO oxidation with excess oxygen. In the propylene oxidation reaction with O2, 1-fold-coordinated Cu on Cu2O(111), 3-fold-coordinated O on Cu2O(110), and 2-fold-coordinated O on Cu2O(100) were identified

  20. Associations of Job Stress Indicators with Oxidative Biomarkers in Japanese Men and Women

    Directory of Open Access Journals (Sweden)

    Jiro Takaki

    2013-12-01

    Full Text Available Some researchers have suggested that oxidative damage may be one of the mechanisms linking job stress with coronary heart disease. The aim of this study was to investigate the association between job stress indicators and oxidative biomarkers. The study included 567 subjects (272 men, 295 women who answered questionnaires related to their work and underwent a medical examination. Job stress evaluated using the demands-control-support model was measured using the Job Content Questionnaire. Effort-reward imbalance was measured using the Effort-Reward Imbalance Questionnaire. Urinary hydrogen peroxide (H2O2 and 8-hydroxy-2'-deoxyguanosine (8-OHdG were measured by the modified ferrous ion oxidation xylenol orange version-1 method and enzyme-linked immunosorbent assay, respectively. In men, the changes in the odds ratios for high urinary H2O2 associated with a 1-standard-deviation (SD increase in worksite social support were 0.69 (95% confidence interval (CI 0.53, 0.91 univariately and 0.68 (95%CI 0.51, 0.90 after adjustment for covariates. The change in the odds ratio for high urinary H2O2 associated with a 1-SD increase in effort-reward ratio was 1.35 (95% CI 1.03, 1.78 after adjustment for covariates. In women, there were no significant associations of the two job stress indicators with urinary H2O2 and 8-OHdG levels after adjustment for covariates (p > 0.05.

  1. Data compilation diffusion in ferrous alloys

    CERN Document Server

    Fisher, David J

    2006-01-01

    This issue comprises an extensive body of selected data, on diffusion in iron-based materials, gleaned from research published in leading journals during the past 70 years. The materials covered range from the almost-pure metal, to high-alloy steels (including metallic glasses) and the data reflect the effect of special conditions (thin films, strain, etc.) upon bulk, surface and pipe diffusion.This publication will constitute an invaluable first port-of-call for anyone looking for a quick guide as to the extent of diffusion which is to be expected to occur during any research project or indus

  2. Markers of protein oxidation

    DEFF Research Database (Denmark)

    Headlam, Henrietta A; Davies, Michael Jonathan

    2004-01-01

    Exposure of proteins to radicals in the presence of O2 gives both side-chain oxidation and backbone fragmentation. These processes can be interrelated, with initial side-chain oxidation giving rise to backbone damage via transfer reactions. We have shown previously that alkoxyl radicals formed...... on the C-3 carbons of Ala, Val, Leu, and Asp residues undergo beta-scission to give backbone alpha-carbon radicals, with the release of the side- chain as a carbonyl compound. We now show that this is a general mechanism that occurs with a wide range of oxidants. The quantitative significance...... of this process depends on the extent of oxidation at C-3 compared with other sites. HO*, generated by gamma radiolysis, gave the highest total carbonyl yield, with protein-bound carbonyls predominating over released. In contrast, metal ion/H2O2 systems, gave more released than bound carbonyls, with this ratio...

  3. Protein oxidation and peroxidation

    DEFF Research Database (Denmark)

    Davies, Michael Jonathan

    2016-01-01

    Proteins are major targets for radicals and two-electron oxidants in biological systems due to their abundance and high rate constants for reaction. With highly reactive radicals damage occurs at multiple side-chain and backbone sites. Less reactive species show greater selectivity with regard...... and modified turnover. In the presence of O2, high yields of peroxyl radicals and peroxides (protein peroxidation) are formed; the latter account for up to 70% of the initial oxidant flux. Protein peroxides can oxidize both proteins and other targets. One-electron reduction results in additional radicals...... and chain reactions with alcohols and carbonyls as major products; the latter are commonly used markers of protein damage. Direct oxidation of cysteine (and less commonly) methionine residues is a major reaction; this is typically faster than with H2O2, and results in altered protein activity and function...

  4. High Current Oxide Cathodes

    National Research Council Canada - National Science Library

    Luhmann, N

    2000-01-01

    The aim of the AASERT supported research is to develop the plasma deposition/implantation process for coating barium, strontium and calcium oxides on nickel substrates and to perform detailed surface...

  5. High Current Oxide Cathodes

    National Research Council Canada - National Science Library

    Luhmann, N

    2000-01-01

    .... The vacuum are plasma deposition gun developed at Lawrence Berkeley National Laboratory (LBNL) has been used to deposit oxides and nitrides with very precise control over deposition rate and composition.

  6. CATALYTIC ENANTIOSELECTIVE ALLYLIC OXIDATION

    NARCIS (Netherlands)

    Rispens, Minze T.; Zondervan, Charon; Feringa, Bernard

    Several chiral Cu(II)-complexes of cyclic amino acids catalyse the enantioselective allylic oxidation of cyclohexene to cyclohexenyl esters. Cyclohexenyl propionate was obtained in 86% yield with e.e.'s up to 61%.

  7. Iron-Mediated Lysosomal Membrane Permeabilization in Ethanol-Induced Hepatic Oxidative Damage and Apoptosis: Protective Effects of Quercetin

    Directory of Open Access Journals (Sweden)

    Yanyan Li

    2016-01-01

    Full Text Available Iron, in its free ferrous states, can catalyze Fenton reaction to produce OH∙, which is recognized as a crucial role in the pathogenesis of alcoholic liver diseases (ALD. As a result of continuous decomposition of iron-containing compounds, lysosomes contain a pool of redox-active iron. To investigate the important role of intralysosomal iron in alcoholic liver injury and the potential protection of quercetin, male C57BL/6J mice fed by Lieber De Carli diets containing ethanol (30% of total calories were cotreated by quercetin or deferoxamine (DFO for 15 weeks and ethanol-incubated mice primary hepatocytes were pretreated with FeCl3, DFO, and bafilomycin A1 at their optimal concentrations and exposure times. Chronic ethanol consumption caused an evident increase in lysosomal redox-active iron accompanying sustained oxidative damage. Iron-mediated ROS could trigger lysosomal membrane permeabilization (LMP and subsequent mitochondria apoptosis. The hepatotoxicity was attenuated by reducing lysosomal iron while being exacerbated by escalating lysosomal iron. Quercetin substantially alleviated the alcoholic liver oxidative damage and apoptosis by decreasing lysosome iron and ameliorating iron-mediated LMP, which provided a new prospective of the use of quercetin against ALD.

  8. Thin films containing oxalate-capped iron oxide nanomaterials deposited on glass substrate for fast Fenton degradation of some micropollutants.

    Science.gov (United States)

    Rambu, Alicia Petronela; Nadejde, Claudia; Schneider, Rudolf J; Neamtu, Mariana

    2018-03-01

    The main goal of the study was to evaluate the catalytic activity of two hybrid nanocatalysts consisting in Fe 3 O 4 nanoparticles modified with either chitosan (CS) or polyethylene glycol (PEG)/ferrous oxalate (FO), and further deposited on solid substrate as thin films. X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM) were employed for the structural and morphological characterizations of the heterogeneous catalysts. The degradation kinetic studies of two reactive azo dye (Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84)) as well as Bisphenol A (BPA) solutions were carried out using Fenton-like oxidation, in the presence of different concentrations of H 2 O 2 , at initial near-neutral pH and room temperature. The results indicated that a low amount of catalytic material (0.15 g/L), deposited as thin film, was able to efficiently trigger dye degradation in solution in the presence of 6.5 mmol/L H 2 O 2 for RB5 and of only 1.6 mmol/L H 2 O 2 in the case of BPA and RY84. In the presence of complex matrices such as WWTP waters, the removal of BPA was low (only 24% for effluent samples). Our findings recommend the studied immobilized nanocatalysts as promising economical tools for the pre-treatment of wastewaters using advanced oxidation processes (AOPs).

  9. Selected serum oxidative stress biomarkers in dogs with non-food-induced and food-induced atopic dermatitis.

    Science.gov (United States)

    Almela, Ramón M; Rubio, Camila P; Cerón, José J; Ansón, Agustina; Tichy, Alexander; Mayer, Ursula

    2018-02-01

    Oxidative stress (OS) has been shown to be involved in the pathogenesis of human and canine atopic dermatitis (AD) through several distinct mechanisms. Selected serum biomarkers of OS (sbOS) have been validated in normal dogs and studied in several canine diseases. To the best of the authors' knowledge, the sbOS evaluated in this study have not previously been described in canine AD. The aims of the study were to evaluate a panel of sbOS in dogs with food-induced (FIAD) and non-food-induced (NFIAD) AD: cupric reducing antioxidant capacity (CUPRAC), ferrous oxidation-xylenol orange (FOX), ferric reducing ability of the plasma (FRAP), paraoxonase-1 (PON1), trolox equivalent antioxidant capacity (TEAC) and serum total thiol (THIOL). The aim was to compare these metabolites with those in healthy control dogs, and to correlate sbOS with validated pruritus and CADESI-04 severity scales in dogs with AD. Forty six healthy, nine NFIAD and three FIAD client-owned dogs were included. The study was designed as a cohort study. There were significant differences in atopic dogs when compared to healthy dogs for all of the sbOS analysed. These findings suggest that OS could play a role in the pathogenesis of canine NFIAD and FIAD. In addition, the evaluation of sbOS could be useful for precision medicine to help to detect atopic dogs that might benefit from antioxidant-targeted therapies. © 2018 ESVD and ACVD.

  10. Mono- and dinuclear non-heme iron–nitrosyl complexes: Models for key intermediates in bacterial nitric oxide reductases

    Energy Technology Data Exchange (ETDEWEB)

    Berto, Timothy C.; Speelman, Amy L.; Zheng, Sheng; Lehnert, Nicolai

    2013-01-01

    High-spin non-heme iron–nitrosyls are of direct interest to both the chemical and biological communities as these species exhibit interesting chemical properties and act as direct models for enzymatic intermediates. The electronic ground state of the ferrous NO complexes, {Fe–NO}7, is best described as high-spin FeIII antiferromagnetically coupled to NO-, generating the spectroscopically observed S = 3/2 ground state. These species have been identified as catalytically relevant to a variety of NO-reducing enzymes such as bacterial nitric oxide reductase (NorBC) and flavo(rubredoxin) nitric oxide reductase (FNOR). Recently, the corresponding one-electron reduced {Fe–NO}8 (nitroxyl) complexes have also been implicated as biologically significant species. In this review the available spectroscopic data for {Fe–NO}7 and {Fe–NO}8 mono- and dinuclear non-heme iron–nitrosyls are summarized, and the implications of these results with respect to the electronic structures and reactivities of these species, in particular towards NO reduction, are discussed.

  11. Titanium oxide fever

    International Nuclear Information System (INIS)

    De Jonge, D.; Visser, J.

    2012-01-01

    One measure to improve air quality is to apply photo-catalytic substances that capture NOx onto the road surface or onto baffle boards alongside the roads. The effect of titanium oxide containing clinkers with coating was discussed in the report 'Demonstration project of air-purifying pavement in Hengelo, The Netherlands' that was published in May 2011. This article examines the way in which the effectiveness of this study was determined. Can titanium oxide containing clinkers and coatings indeed capture NOx?. [nl

  12. Are there multiple mechanisms of anaerobic sulfur oxidation with ferric iron in Acidithiobacillus ferrooxidans?

    Science.gov (United States)

    Kucera, Jiri; Pakostova, Eva; Lochman, Jan; Janiczek, Oldrich; Mandl, Martin

    2016-06-01

    To clarify the pathway of anaerobic sulfur oxidation coupled with dissimilatory ferric iron reduction in Acidithiobacillus ferrooxidans strain CCM 4253 cells, we monitored their energy metabolism gene transcript profiles. Several genes encoding electron transporters involved in aerobic iron and sulfur respiration were induced during anaerobic growth of ferrous iron-grown cells. Most sulfur metabolism genes were either expressed at the basal level or their expression declined. However, transcript levels of genes assumed to be responsible for processing of elemental sulfur and other sulfur intermediates were elevated at the beginning of the growth period. In contrast, genes with predicted functions in formation of hydrogen sulfide and sulfate were significantly repressed. The main proposed mechanism involves: outer membrane protein Cyc2 (assumed to function as a terminal ferric iron reductase); periplasmic electron shuttle rusticyanin; c4-type cytochrome CycA1; the inner membrane cytochrome bc1 complex I; and the quinone pool providing connection to the sulfur metabolism machinery, consisting of heterodisulfide reductase, thiosulfate:quinone oxidoreductase and tetrathionate hydrolase. However, an alternative mechanism seems to involve a high potential iron-sulfur protein Hip, c4-type cytochrome CycA2 and inner membrane cytochrome bc1 complex II. Our results conflict with findings regarding the type strain, indicating strain- or phenotype-dependent pathway variation. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  13. Thin zirconium oxides

    International Nuclear Information System (INIS)

    Oviedo, Cristina

    2000-01-01

    Polycrystalline Zr and two pure Zr single-crystal samples, one oriented with the normal to the surface parallel to the c-axis of the hcp structure (Z1) and the other with the normal perpendicular to c (Z2), were oxidised at 10 -8 , 10 -7 and 10 -6 Torr and room temperature. Oxidation kinetics, composition and thicknesses of the oxide films formed in each case were analyzed using XPS (X-ray Photoelectron Spectroscopy) as the main technique. The oxidation kinetics followed logarithmic laws in all cases. The deconvolution of XPS Zr3d peaks indicated the formation of two Zr-O compounds before the formation of ZrO 2 . Varying the photoelectrons take-off angle, the compound distribution inside the oxide films could be established. Thus, it was confirmed that the most external oxide, in contact with the gas, was ZrO 2 . The thickness of the films grown at the different pressures was determined. In the polycrystalline samples, thicknesses between 15 and 19 ± 2Angstroem were obtained for pressures between 10 -8 and 10 -6 Torr, in close coincidence with the determined ones for Z2. The thicknesses measured in Z1 were smaller, reaching 13 ± 2Angstroem for the oxidations performed at 10 -6 Torr. (author)

  14. Carbon isotope fractionation of chlorinated ethenes during oxidation by Fe{sup 2+} activated persulfate

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, Massimo, E-mail: m2marche@uwaterloo.ca [Departament de Cristallografia, Mineralogia i Diposits Minerals, Universitat de Barcelona, Barcelona, Catalunya 08028 (Spain); Earth and Environmental Department, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada); Aravena, Ramon [Earth and Environmental Department, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada); Sra, Kanwartej S. [Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada); Golder Associates Inc, Toronto, Ontario, Canada L5N 5Z7 (Canada); Thomson, Neil R. [Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada); Otero, Neus; Soler, Albert [Departament de Cristallografia, Mineralogia i Diposits Minerals, Universitat de Barcelona, Barcelona, Catalunya 08028 (Spain); Mancini, Silvia [Golder Associates Inc, Toronto, Ontario, Canada L5N 5Z7 (Canada)

    2012-09-01

    The increased use of persulfate (S{sub 2}O{sub 8}{sup 2-}) for in situ chemical oxidation to treat groundwater and soils contaminated by chlorinated hydrocarbon compounds (CHCs) requires unbiased methods to assess treatment performance. Stable carbon isotope analysis offers a potential tool for assessing the in situ treatment performance of persulfate at sites contaminated with CHCs. This study investigated the extent of C isotope fractionation during oxidation of tetrachloroethene (PCE), trichloroethene (TCE) and cis-dichloroethene (cis-DCE) by persulfate activated by ferrous ion (Fe{sup 2+}). An average carbon isotope enrichment factor {epsilon}{sub bulk} of - 4.9 Per-Mille-Sign for PCE, - 3.6 Per-Mille-Sign for TCE and - 7.6 Per-Mille-Sign for cis-DCE were obtained in batch experiments. Variations in the initial S{sub 2}O{sub 8}{sup 2-}/Fe{sup 2+}/CHC molar ratios did not result in any significant differences in carbon isotope fractionation. The occurrence of carbon isotope fractionation during oxidation and the lack of dependence of enrichment factors upon the S{sub 2}O{sub 8}{sup 2-}/Fe{sup 2+}/CHC molar ratio demonstrate that carbon isotope analysis can potentially be used at contaminated sites as an additional technique to estimate treatment efficacy during oxidation of CHCs by Fe{sup 2+} activated persulfate. Highlights: Black-Right-Pointing-Pointer The performance of in situ chemical oxidation (ISCO) is still difficult to assess. Black-Right-Pointing-Pointer We investigated the potential of carbon isotope analysis as a new assessing tool. Black-Right-Pointing-Pointer C isotope of PCE, TCE and DCE oxidized by persulfate activated by Fe{sup 2+} was measured. Black-Right-Pointing-Pointer Enrichment factors of - 4.9 Per-Mille-Sign for PCE, - 3.6 Per-Mille-Sign for TCE and - 7.6 Per-Mille-Sign for cisDCE were obtained. Black-Right-Pointing-Pointer Carbon isotope can potentially be used to estimate the ISCO treatment efficacy.

  15. Hydrogen Peroxide Cycling in Acidic Geothermal Environments and Potential Implications for Oxidative Stress

    Science.gov (United States)

    Mesle, M.; Beam, J.; Jay, Z.; Bodle, B.; Bogenschutz, E.; Inskeep, W.

    2014-12-01

    Hydrogen peroxide (H2O2) may be produced in natural waters via photochemical reactions between dissolved oxygen, organic carbon and light. Other reactive oxygen species (ROS) such as superoxide and hydroxyl radicals are potentially formed in environments with high concentrations of ferrous iron (Fe(II), ~10-100 μM) by reaction between H2O2 and Fe(II) (i.e., Fenton chemistry). Thermophilic archaea and bacteria inhabiting acidic iron-oxide mats have defense mechanisms against both extracellular and intracellular peroxide, such as peroxiredoxins (which can degrade H2O2) and against other ROS, such as superoxide dismutases. Biological cycling of H2O2 is not well understood in geothermal ecosystems, and geochemical measurements combined with molecular investigations will contribute to our understanding of microbial response to oxidative stress. We measured H2O2 and other dissolved compounds (Fe(II), Fe(III), H2S, O2), as well as photon flux, pH and temperature, over time in surface geothermal waters of several acidic springs in Norris Geyser Basin, Yellowstone National Park, WY (Beowulf Spring and One Hundred Spring Plain). Iron-oxide mats were sampled in Beowulf Spring for on-going analysis of metatranscriptomes and RT-qPCR assays of specific stress-response gene transcription (e.g., superoxide dismutases, peroxiredoxins, thioredoxins, and peroxidases). In situ analyses show that H2O2 concentrations are lowest in the source waters of sulfidic systems (ca. 1 μM), and increase by two-fold in oxygenated waters corresponding to Fe(III)-oxide mat formation (ca. 2 - 3 μM). Channel transects confirm increases in H2O2 as a function of oxygenation (distance). The temporal dynamics of H2O2, O2, Fe(II), and H2S in Beowulf geothermal waters were also measured during a diel cycle, and increases in H2O2 were observed during peak photon flux. These results suggest that photochemical reactions may contribute to changes in H2O2. We hypothesize that increases in H2O2 and O2

  16. Porous ceramics out of oxides

    International Nuclear Information System (INIS)

    Bakunov, V.S.; Balkevich, V.L.; Vlasov, A.S.; Guzman, I.Ya.; Lukin, E.S.; Poluboyarinov, D.N.; Poliskij, R.Ya.

    1977-01-01

    A review is made of manufacturing procedures and properties of oxide ceramics intended for high-temperature thermal insulation and thermal protection applications. Presented are structural characteristics of porous oxide refractories and their properties. Strength and thermal conductivity was shown to depend upon porosity. Described is a procedure for manufacturing porous ceramic materials from aluminium oxide, zirconium dioxide, magnesium oxide, beryllium oxide. The thermal resistance of porous ceramics from BeO is considerably greater than that of other high-refractoriness oxides. Listed are areas of application for porous materials based on oxides

  17. Interactions of nitric oxide with lipid peroxidation products under aerobic conditions: inhibitory effects on the formation of malondialdehyde and related thiobarbituric acid-reactive substances.

    Science.gov (United States)

    d'Ischia, M; Palumbo, A; Buzzo, F

    2000-02-01

    Under aerobic conditions, exposure of peroxidized lipids to nitric oxide (NO) was found to result in a rapid decrease in the levels of thiobarbituric acid-reactive substances (TBARS). Addition of 10-100 microM NO to rat brain homogenates preincubated for 2 h at 37 degrees C caused up to a 20% decrease in the levels of TBARS compared to controls. A similar inhibitory effect was observed on TBARS produced by Fe(2+)-induced decomposition of 15-hydroperoxyeicosatetraenoic acid (15-HPETE), due apparently to NO-induced decomposition of the hydroperoxide (ferrous oxidation/xylenol orange assay). Prostaglandin G(2) (PGG(2), 35 microM), as a model bicyclic endoperoxide, and malondialdehyde (MDA, 20 microM), the main component of TBARS, proved also susceptible to degradation by NO or NO donors (diethylamine NONOate, DEA/NO) at concentrations of 100 microM or higher in 0.05 M phosphate buffer, pH 7.4, and at 37 degrees C, as indicated by the reduced response to the TBA assay. No significant effect on TBARS determination was caused by nitrite ions. These and other data indicate that NO can inhibit TBARS formation by decomposing primary lipid peroxidation products, chiefly 15-HPETE and related hydroperoxides, and, to a lesser extent, later stage TBARS precursors, including bicyclic endoperoxides and MDA, via nitrosation and other oxidative routes, without however affecting chromogenic reactions during the assay. Copyright 2000 Academic Press.

  18. Miniaturized and green method for determination of chemical oxygen demand using UV-induced oxidation with hydrogen peroxide and single drop microextraction

    International Nuclear Information System (INIS)

    Akhoundzadeh, Jeyran; Chamsaz, Mahmoud; Costas, Marta; Lavilla, Isela; Bendicho, Carlos

    2013-01-01

    We report on a green method for the determination of low levels of chemical oxygen demand. It is based on the combination of (a) UV-induced oxidation with hydrogen peroxide, (b) headspace single-drop microextraction with in-drop precipitation, and (c) micro-turbidimetry. The generation of CO 2 after photolytic oxidation followed by its sequestration onto a microdrop of barium hydroxide gives rise to a precipitate of barium carbonate which is quantified by turbidimetry. UV-light induced oxidation was studied in the absence and presence of H 2 O 2 , ultrasound, and ferrous ion. Determinations of chemical oxygen demand were performed using potassium hydrogen phthalate as a model compound. The optimized method gives a calibration curve that is linear between 3.4 and 20 mg L −1 oxygen. The detection limit was 1.2 mg L −1 of oxygen, and the repeatability (as relative standard deviation) was around 5 %. The method was successfully applied to the determination of chemical oxygen demand in different natural waters and a synthetic wastewater. (author)

  19. Probing the oxidation state of iron in the deep mantle using high P,T Mössbauer spectroscopy

    Science.gov (United States)

    McCammon, C. A.; Kupenko, I.; Sinmyo, R.; Cerantola, V.; Potapkin, V.; Chumakov, A. I.; Kantor, A.; Rüffer, R.; Dubrovinsky, L. S.

    2014-12-01

    The bulk of the Earth's interior is not directly accessible, yet redox processes occurring deep within drive many of the events observed at its surface. Laboratory studies of the relevant minerals at the appropriate pressure and temperature conditions have been pivotal in advancing our understanding of the Earth's interior. Iron plays an important role because it is the only major element with multiple electronic configurations (oxidation and spin state); however most of our knowledge regarding the oxidation state of iron in deep mantle phases is based on measurements of samples quenched from high temperature and sometimes also from high pressure. Mössbauer spectroscopy has been a key player in such studies and results on quenched samples have shown that the oxidation state of iron varies considerably through the mantle, from predominantly ferrous iron in upper mantle and transition zone phases to roughly 50% ferric iron in silicate perovskite (bridgmanite) due to the strong affinity of ferric iron for that phase in the presence of trivalent aluminium. Mössbauer measurements at pressures and temperatures along the geotherm are impractical using conventional radioactive sources due to their low brightness and the extremely limited possibilities for focusing in a laboratory setting. To address these limitations, we have developed an energy domain Synchrotron Mössbauer Source (SMS) on beamline ID18 at the European Synchrotron Radiation Facility that enables rapid collection of high quality energy domain Mössbauer spectra, and coupled with a portable double-sided laser heating system, SMS spectra can be collected on iron-containing mantle phases at pressures and temperatures up to those near the Earth's core in only a few hours (or less). The presentation will showcase recent results documenting in situ determination of iron oxidation state in lower mantle phases and discuss their implications for redox sensitive processes taking place throughout the Earth

  20. Microbial oxidation and reduction of inorganic sulphur compounds in relation to the development and control of microorganisms active in leaching operations. Part of a coordinated programme on bacterial leaching of uranium ores

    International Nuclear Information System (INIS)

    Tuovinen, O.H.

    1977-01-01

    The project considers the use of Thiobacillus ferroxidans type bacteria for the leaching of metals from ores. The various ways by which Thiobacillus ferroxidans utilizes inorganic sulfur compounds for oxidation, energy, growth and synthesis of cellular material were studied. The report briefly describes the scope and background of the project, and a list of publications describing experimental methods and research materials used is given. Unpublished work commenced during the Research Contract includes three major projects: (1) Transition of Thiobacillus ferroxidans from heterotrophic growth on fucose to autotropic growth on ferrous-iron; (2) development of a method to determine the ATP-content of bacteria attached to ore particles; (3) microbiological and chemical interactions of inorganic sulfur compounds. These three projects are summarized briefly

  1. Single sheet iron oxides

    DEFF Research Database (Denmark)

    Yin, Zhou

    activity. LDH single sheets have been reported to be effective sorbents, catalysts in electrochemical and photochemical reactions, and building thin films together with other nanomaterials for designing new functionalities. Here we focus on the delamination of FeII-FeIII LDHs into single sheet iron oxide...... was rapid compared to other iron oxides, reaching equilibrium within 60 minutes. Arsenic sorption and acid-base titration data could be successfully described with a 1pk Basic Stern Model (BSM). The point of zero charge was around 8. The intrinsic surface complexation equilibrium constants (log K...... became abundant at low pH. (3) Electrochemical reduction of chlorinated compounds using an SSI modified electrode. Here, the electrochemical reactivity of SSIs coated on indium tin oxide coated glass electrodes was investigated. Iron on the SSI modified electrode showed a typical Cyclic Voltammetry...

  2. Volume reduction by oxidation

    International Nuclear Information System (INIS)

    Kuribayashi, H.; Hasegawa, A.; Koshiba, Y.; Yamanaka, A.

    1984-01-01

    JGC Corporation has been actively investigating the treatment of various combustible and organic wastes generated at nuclear power stations and reprocessing plants. In particular, JGC has analyzed three new technologies which produce dramatic volume reductions and complete conversion of wastes into inorganic substances for durable storage and disposal. Those technologies are; Incineration, Wet oxidation and Photooxidation. Incineration is an excellent volume reducer for combustible wastes, and wet oxidation, using hydrogen peroxide, is also a good way for reducing spent ion-exchange resins without any off-gas problems. Photooxidation is a new technology to purify polluted water for recycled use in the stations without th release of contaminated water to the environment. Polluted water may include NH4+, detergents, chelating agents and other organic decontamination agents. These VR technologies are all based on ''Oxidation'' from which the title of this paper comes

  3. Methanol partial oxidation reformer

    Science.gov (United States)

    Ahmed, Shabbir; Kumar, Romesh; Krumpelt, Michael

    1999-01-01

    A partial oxidation reformer comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell.

  4. Ethylene Oxide Gaseous Sterilization

    Science.gov (United States)

    Ernst, Robert R.; Shull, James J.

    1962-01-01

    The duration of the equilibration period between admission of water vapor and subsequent introduction of gaseous ethylene oxide to an evacuated sterilizer chamber was studied with respect to its effect on the inactivation of spores of Bacillus subtilis var. niger under simulated practical conditions. Introduction of a water-adsorbing cotton barrier between the spores and an incoming gas mixture of water vapor and ethylene oxide caused a marked increase in the observed thermochemical death time of the spore populations. This effect was negated by admission of water vapor one or more minutes prior to introduction of ethylene oxide gas. Increases in temperature and relative humidity of the system promoted passage of water vapor through the cotton barriers and diminished their effect. PMID:13890660

  5. Oxidation of orthopaedic UHMWPE.

    Science.gov (United States)

    Costa, L; Jacobson, K; Bracco, P; Brach del Prever, E M

    2002-04-01

    Retrieved EtO sterilised acetabular cups usually show much less degradation than gamma-ray sterilised cups. Some of our retrieved EtO sterilised cups did, however, reveal unexpected bulk oxidation. It was observed that this oxidation was always accompanied by whitening of the material. This whitening was found to be due to a break-up of the compression moulded material into its original particles. It was noticed that there was no oxidation in all parts, where the break-up and whitening appeared. The oxidation did, however, occur exclusively in the parts where there was a badly consolidated material. Upon examining shelf aged, unsterilised samples, it was found that the degradation was also present here. This shows that the observed phenomenon is not due to the service in vivo and that it must originate from the processing step. Just as for the retrieved samples, the shelf aged cups only showed oxidation in the bulk and not at the surface. It was concluded that the material used for the cups had been badly fused together during the compression moulding and that the machining had created a bad stress situation in the cups leading to a break-up of the particles. The mechanism that initiates the oxidation is not known, but it is believed that the distribution depends on how the internal stresses have acted to break up the structure. In the areas where the particles have been separated, there is probably a higher availability of oxygen than what is normally observed in UHMWPE.

  6. Oxidation by metal salts

    International Nuclear Information System (INIS)

    Makhon'kov, D.I.; Cheprakov, A.V.; Rodkin, M.A.; Mil'chenko, A.Yu.; Beletskaya, I.P.

    1986-01-01

    Oxidation of toluene and para-substituted toluenes containing electron acceptor groups: p-toluic acid, p-methyltoluylate and p-nitrotoluene by ammonium cerium (4) nitrate and ammonium cerium (4) sulfate in aqueous solutions of trifluoroacetic acid in the presence of chlorides and bromides of alkali metals is studied. The rate and selectivity of oxidative halogenation in side chain and/or aromatic ring under the conditions studied depend both on the nature of substrate and halogenide-ion and on the reaction conditions and ligand surrounding of cerium (4) atom

  7. Sintering of beryllium oxide

    International Nuclear Information System (INIS)

    Caillat, R.; Pointud, R.

    1955-01-01

    This study had for origin to find a process permitting to manufacture bricks of beryllium oxide of pure nuclear grade, with a density as elevated as possible and with standardized shape. The sintering under load was the technique kept for the manufacture of the bricks. Because of the important toxicity of the beryllium oxide, the general features for the preliminary study of the sintering, have been determined while using alumina. The obtained results will be able to act as general indication for ulterior studies with sintering under load. (M.B.) [fr

  8. Non-invasive continuous monitoring of pro-oxidant effects of engineered nanoparticles on aquatic microorganisms.

    Science.gov (United States)

    Santschi, Christian; Von Moos, Nadia; Koman, Volodymyr B; Slaveykova, Vera I; Bowen, Paul; Martin, Olivier J F

    2017-03-07

    Engineered nanomaterials (ENMs) are key drivers for the development of highly sophisticated new technologies. As all new attainments, the rapidly increasing used of ENMs raise concerns about their safety for the environment and humans. There is growing evidence showing that if engineered nanomaterials are released into the environment, there is a possibility that they could cause harm to aquatic microorganisms. Among the divers effects triggering their toxicity the ability of ENMs to generate reactive oxygen species (ROS) capable of oxidizing biomolecules is currently considered a central mechanism of toxicity. Therefore, development of sensitive tools for quantification of the ROS generation and oxidative stress are highly sought. After briefly introducing ENMs-induced ROS generation and oxidative stress in the aquatic microorganisms (AMOs), this overview paper focuses on a new optical biosensor allowing sensitive and dynamic measurements of H 2 O 2 in real-time using multiscattering enhanced absorption spectroscopy. Its principle is based on sensitive absorption measurements of the heme protein cytochrome c whose absorption spectrum alters with the oxidation state of constituent ferrous Fe II and ferric Fe III . For biological applications cytochrome c was embedded in porous random media resulting in an extended optical path length through multiple scattering of light, which lowers the limit of detection to a few nM of H 2 O 2 . The sensor was also integrated in a microfluidic system containing micro-valves and sieves enabling more complex experimental conditions. To demonstrate its performance, abiotic absorption measurements of low concentrations of dye molecules and 10 nm gold particles were carried out achieving limits of detection in the low nM range. Other biologically relevant reactive oxygen species can be measured at sub-μM concentrations, which was shown for glucose and lactate through enzymatic reactions producing H 2 O 2 . In ecotoxicological

  9. How different oxidation states of crystalline myoglobin are influenced by X-rays.

    Science.gov (United States)

    Hersleth, Hans-Petter; Andersson, K Kristoffer

    2011-06-01

    X-ray induced radiation damage of protein crystals is well known to occur even at cryogenic temperatures. Redox active sites like metal sites seem especially vulnerable for these radiation-induced reductions. It is essential to know correctly the oxidation state of metal sites in protein crystal structures to be able to interpret the structure-function relation. Through previous structural studies, we have tried to characterise and understand the reactions between myoglobin and peroxides. These reaction intermediates are relevant because myoglobin is proposed to take part as scavenger of reactive oxygen species during oxidative stress, and because these intermediates are similar among the haem peroxidases and oxygenases. We have in our previous studies shown that these different myoglobin states are influenced by the X-rays used. In this study, we have in detail investigated the impact that X-rays have on these different oxidation states of myoglobin. An underlying goal has been to find a way to be able to determine mostly unreduced states. We have by using single-crystal light absorption spectroscopy found that the different oxidation states of myoglobin are to a different extent influenced by the X-rays (e.g. ferric Fe(III) myoglobin is faster reduced than ferryl Fe(IV)═O myoglobin). We observe that the higher oxidation states are not reduced to normal ferrous Fe(II) or ferric Fe(III) states, but end up in some intermediate and possibly artificial states. For ferric myoglobin, it seems that annealing of the radiation-induced/reduced state can reversibly more or less give the starting point (ferric myoglobin). Both scavengers and different dose-rates might influence to which extent the different states are affected by the X-rays. Our study shows that it is essential to do a time/dose monitoring of the influence X-rays have on each specific redox-state with spectroscopic techniques like single-crystal light absorption spectroscopy. This will determine to which

  10. Serum Iron and Nitric Oxide Production in Trypanosoma brucei ...

    African Journals Online (AJOL)

    JTEkanem

    by centrifugation of the clear part of blood after clotting at 3,000g for 15min and kept frozen until required, usually after 24hrs. Determination of serum iron level. The serum iron level was determined spectrophotometrically by the O- phenanthroline method16. Ferrous iron reacts with o-phenonthroline to form an orange-red ...

  11. Optimisation of aqueous synthesis of iron oxide nanoparticles for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Bonvin, Debora; Hofmann, Heinrich; Mionic Ebersold, Marijana, E-mail: Marijana.Mionic-Ebersold@chuv.ch [Ecole polytechnique fédérale de Lausanne (EPFL), Powder Technology Laboratory, Institute of Materials, School of Engineering (Switzerland)

    2016-12-15

    Iron oxide nanoparticles (IONPs) were prepared via aqueous synthesis which combines alkaline co-precipitation (CP) of ferric and ferrous precursors with mild hydrothermal (HT) treatment without cupping agents (CA). In this novel synthesis route, CP + HT, we found the optimal synthesis conditions to obtain IONPs without a second phase and with the size larger than in standard CP: the equal number of Fe(II) and Fe(III) ions are co-precipitated with 6 M ammonia and further HT treated in mild conditions (120 °C for 24 h) without CA. The IONPs obtained by novel CP + HT route had faceted rectangular morphology, a mean TEM diameter of 21.5 ± 6.3 nm, a hydrodynamic diameter of 30.2 ± 9.1 nm and a zeta potential at pH 4 of 48.2 ± 0.6 mV. After the subsequent oxidation step, the final product (IONPs) was studied by XRD, FTIR and XPS, which confirmed the desired structure of γ-Fe{sub 2}O{sub 3}. Importantly, this synthesis was especially planned for the preparation of IONPs for biomedical applications. Thus, our novel synthesis was designed to be compliant with the regulations of nano-safety: no special atmosphere, no complex multistep size separation, no organic solvents or solvent exchange, no CA and their washing and the use of low temperature in the final optimised conditions. In addition, this simple synthesis route combines the CP and HT methods, which are both proven to be scalable. Moreover, repeatability and reproducibility of the optimal CP + HT synthesis were confirmed on the lab-scale; more than 100 repetitions with different dishes, different operators and different batches of chemicals were performed.

  12. Photo-Fenton and Fenton Oxidation of Recalcitrant Industrial Wastewater Using Nanoscale Zero-Valent Iron

    Directory of Open Access Journals (Sweden)

    Henrik Hansson

    2012-01-01

    Full Text Available There is a need for the development of on-site wastewater treatment technologies suitable for “dry-process industries,” such as the wood-floor sector. Due to the nature of their activities, these industries generate lower volumes of highly polluted wastewaters after cleaning activities. Advanced oxidation processes such as Fenton and photo-Fenton, are potentially feasible options for treatment of these wastewaters. One of the disadvantages of the Fenton process is the formation of large amounts of ferrous iron sludge, a constraint that might be overcome with the use of nanoscale zero-valent iron (nZVI powder. Wastewater from a wood-floor industry with initial COD of 4956 mg/L and TOC of 2730 mg/L was treated with dark-Fenton (nZVI/H2O2 and photo-Fenton (nZVI/H2O2/UV applying a 2-level full-factorial experimental design. The highest removal of COD and TOC (80% and 60%, resp. was achieved using photo-Fenton. The supply of the reactants in more than one dose during the reaction time had significant and positive effects on the treatment efficiency. According to the results, Fenton and mostly photo-Fenton are promising treatment options for these highly recalcitrant wastewaters. Future investigations should focus on optimizing treatment processes and assessing toxic effects that residual pollutants and the nZVI might have. The feasibility of combining advanced oxidation processes with biological treatment is also recommended.

  13. Uranium oxidation: characterization of oxides formed by reaction with water

    International Nuclear Information System (INIS)

    Fuller, E.L. Jr.; Smyrl, N.R.; Condon, J.B.; Eager, M.H.

    1983-01-01

    Three different uranium oxide samples have been characterized with respect to the different preparation techniques. Results show that the water reaction with uranium metal occurs cyclically forming laminar layers of oxide which spall off due to the strain at the oxide/metal interface. Single laminae are released if liquid water is present due to the prizing penetration at the reaction zone. The rate of reaction of water with uranium is directly proportional to the amount of adsorbed water on the oxide product. Rapid transport is effected through the open hydrous oxide product. Dehydration of the hydrous oxide irreversibly forms a more inert oxide which cannot be rehydrated to the degree that prevails in the original hydrous product of uranium oxidation with water. 27 figures

  14. Uranium oxidation: characterization of oxides formed by reaction with water

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, E.L. Jr.; Smyrl, N.R.; Condon, J.B.; Eager, M.H.

    1983-04-27

    Three different uranium oxide samples have been characterized with respect to the different preparation techniques. Results show that the water reaction with uranium metal occurs cyclically forming laminar layers of oxide which spall off due to the strain at the oxide/metal interface. Single laminae are released if liquid water is present due to the prizing penetration at the reaction zone. The rate of reaction of water with uranium is directly proportional to the amount of adsorbed water on the oxide product. Rapid transport is effected through the open hydrous oxide product. Dehydration of the hydrous oxide irreversibly forms a more inert oxide which cannot be rehydrated to the degree that prevails in the original hydrous product of uranium oxidation with water. 27 figures.

  15. Green oxidations: Titanium dioxide induced tandem oxidation coupling reactions

    OpenAIRE

    Jeena, Vineet; Robinson, Ross S

    2009-01-01

    Summary The application of titanium dioxide as an oxidant in tandem oxidation type processes is described. Under microwave irradiation, quinoxalines have been synthesized in good yields from the corresponding ?-hydroxyketones.

  16. Protein oxidation and ageing

    DEFF Research Database (Denmark)

    Linton, S; Davies, Michael Jonathan; Dean, R T

    2001-01-01

    of redox-active metal ions that could catalyse oxidant formation. As a result of this decrease in antioxidant defences, and increased rate of ROS formation, it is possible that the impact of ROS increases with age. ROS are known to oxidise biological macromolecules, with proteins an important target...

  17. Solid Oxide Fuel Cell

    DEFF Research Database (Denmark)

    2010-01-01

    The solid oxide fuel cell comprising a metallic support material, an active anode layer consisting of a good hydrocarbon cracking catalyst, an electrolyte layer, an active cathode layer, and a transition layer consisting of preferably a mixture of LSM and a ferrite to the cathode current collector...

  18. Oxidative stress in myopia.

    Science.gov (United States)

    Francisco, Bosch-Morell; Salvador, Mérida; Amparo, Navea

    2015-01-01

    Myopia affected approximately 1.6 billion people worldwide in 2000, and it is expected to increase to 2.5 billion by 2020. Although optical problems can be corrected by optics or surgical procedures, normal myopia and high myopia are still an unsolved medical problem. They frequently predispose people who have them to suffer from other eye pathologies: retinal detachment, glaucoma, macular hemorrhage, cataracts, and so on being one of the main causes of visual deterioration and blindness. Genetic and environmental factors have been associated with myopia. Nevertheless, lack of knowledge in the underlying physiopathological molecular mechanisms has not permitted an adequate diagnosis, prevention, or treatment to be found. Nowadays several pieces of evidence indicate that oxidative stress may help explain the altered regulatory pathways in myopia and the appearance of associated eye diseases. On the one hand, oxidative damage associated with hypoxia myopic can alter the neuromodulation that nitric oxide and dopamine have in eye growth. On the other hand, radical superoxide or peroxynitrite production damage retina, vitreous, lens, and so on contributing to the appearance of retinopathies, retinal detachment, cataracts and so on. The objective of this review is to suggest that oxidative stress is one of the key pieces that can help solve this complex eye problem.

  19. Dopamine Oxidation and Autophagy

    Directory of Open Access Journals (Sweden)

    Patricia Muñoz

    2012-01-01

    Full Text Available The molecular mechanisms involved in the neurodegenerative process of Parkinson's disease remain unclear. Currently, there is a general agreement that mitochondrial dysfunction, α-synuclein aggregation, oxidative stress, neuroinflammation, and impaired protein degradation are involved in the neurodegeneration of dopaminergic neurons containing neuromelanin in Parkinson's disease. Aminochrome has been proposed to play an essential role in the degeneration of dopaminergic neurons containing neuromelanin by inducing mitochondrial dysfunction, oxidative stress, the formation of neurotoxic α-synuclein protofibrils, and impaired protein degradation. Here, we discuss the relationship between the oxidation of dopamine to aminochrome, the precursor of neuromelanin, autophagy dysfunction in dopaminergic neurons containing neuromelanin, and the role of dopamine oxidation to aminochrome in autophagy dysfunction in dopaminergic neurons. Aminochrome induces the following: (i the formation of α-synuclein protofibrils that inactivate chaperone-mediated autophagy; (ii the formation of adducts with α- and β-tubulin, which induce the aggregation of the microtubules required for the fusion of autophagy vacuoles and lysosomes.

  20. Partial Oxidation of n-Pentane over Vanadium Phosphorus Oxide ...

    African Journals Online (AJOL)

    NICOLAAS

    The selective oxidation ofn-pentane to value-added products, maleic anhydride or phthallic anhydride by vanadium phosphorus oxide loaded on hydroxyapatites as catalysts and oxygen as oxidant was investigated. Hydroxyapatite (HAp) and cobalt- hydroxyapatite (Co-HAp) were prepared by the co-precipitation method ...

  1. Nanostructured transition metal oxides useful for water oxidation catalysis

    Science.gov (United States)

    Frei, Heinz M; Jiao, Feng

    2013-12-24

    The present invention provides for a composition comprising a nanostructured transition metal oxide capable of oxidizing two H.sub.2O molecules to obtain four protons. In some embodiments of the invention, the composition further comprises a porous matrix wherein the nanocluster of the transition metal oxide is embedded on and/or in the porous matrix.

  2. Staged membrane oxidation reactor system

    Science.gov (United States)

    Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

    2012-09-11

    Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

  3. Electrochemical analysis of metal oxides

    Czech Academy of Sciences Publication Activity Database

    Grygar, Tomáš; Bezdička, Petr; Hradil, David; Pikna, L.

    90-91, - (2003), s. 45-50 ISSN 1012-0394 Institutional research plan: CEZ:AV0Z4032918 Keywords : powder electroanalysis * Fe oxides * Mn oxides Subject RIV: CA - Inorganic Chemistry Impact factor: 0.687, year: 2003

  4. Thin film metal-oxides

    CERN Document Server

    Ramanathan, Shriram

    2009-01-01

    Presents an account of the fundamental structure-property relations in oxide thin films. This title discusses the functional properties of thin film oxides in the context of applications in the electronics and renewable energy technologies.

  5. Metabolic flexibility of the Fe(II)-oxidizing phototropic strain Rhodopseudomonas palustris TIE1 and its potential role in microbial iron cycling

    Science.gov (United States)

    Schmidt, C.; Oswald, K.; Melton, E. D.; Kappler, A.

    2012-04-01

    The biogeochemical conversion of iron(II) and iron(III) is widespread in many aquatic and terrestrial environments. In the anoxic regime of soils and sediments the conversion and alternation of the iron redox state is predominantly run by microorganisms that are thought to gain life-sustaining energy by the oxidation and/or reduction of ferrous/ferric components. The spatial arrangement of microbial iron(II) oxidation and iron(III) reduction is largely controlled by the availability of the required electron acceptor and electron donor, as well as the essential source of energy (i.e. light or chemical energy). The physico-chemical patterns of many microbial environments undergo dynamic variations (i.e. diurnal and seasonal changes) as a function of natural external forces (i.e. seasonality, storm events, algae blooms) which strongly affects the local budget of organic carbon and nutrients, as well as the day light penetration. Such fluctuations force microorganisms either to follow the flow of substrate or to switch their metabolism to alternative electron acceptors and/or donors. Different photoferrotrophic bacteria have been shown to be able to grow either on organic (heterotrophic) or inorganic (autotrophic) substrates while exploiting light as their energy source. Within the frame of this study the preference for organic substrates (lactate and acetate) and/or ferrous iron (in simultaneous presence) for photo(ferro)trophic growth of Rhodopseudomonas palustris TIE1 has been investigated in detail. Rates of iron oxidation, acetate/lactate consumption and growth have been followed over time as a function of different lactate to acetate to iron(II) ratios. Additional experiments have been designed to evaluate the potential of Rhodopseudomonas palustris TIE1 to contribute to the redox cycling of iron. TIE1 has been grown in a batch set-up in which the iron(III)-reducing strain Shewanella oneidensis MR1 has been incubated at different ferrihydrite concentrations in

  6. Self-assembled manganese oxide structures through direct oxidation

    KAUST Repository

    Zhao, Chao

    2012-12-01

    The morphology and phase of self-assembled manganese oxides during different stages of thermal oxidation were studied. Very interesting morphological patterns of Mn oxide films were observed. At the initial oxidation stage, the surface was characterized by the formation of ring-shaped patterns. As the oxidation proceeded to the intermediate stage, concentric plates formed to relax the compressive stress. Our experimental results gave a clear picture of the evolution of the structures. We also examined the properties of the structures. © 2012 Elsevier B.V.

  7. Oxidative Decarboxylation of Levulinic Acid by Cupric Oxides

    Directory of Open Access Journals (Sweden)

    Lu Lin

    2010-11-01

    Full Text Available In this paper, cupric oxides was found to effectively oxidize levulinic acid (LA and lead to the decarboxylation of levulinic acid to 2-butanone. The effects of cupric oxide dosage, reaction time and initial pH value were investigated in batch experiments and a plausible mechanism was proposed. The results showed that LA decarboxylation over cupric oxides at around 300 °C under acidic conditions produced the highest yield of butanone (67.5%. In order to elucidate the catalytic activity of cupric oxides, XRD, AFM, XPS and H2-TPR techniques was applied to examine their molecular surfaces and their effects on the reaction process.

  8. Low Temperature Oxidation of Methane: The Influence of Nitrogen Oxides

    DEFF Research Database (Denmark)

    Bendtsen, Anders Broe; Glarborg, Peter; Dam-Johansen, Kim

    2000-01-01

    An experimental investigation of methane oxidation in the presence of NO and NO2 has been made in an isothermal plug-flow reactor at 750-1250K. The temperature for on-set of oxidation was lowered by 250 K in the presence of NO or NO2 at residence times of 200 ms. At shorter residence times (140 ms......) this enhancement effect is reduced for NO but maintained for NO2. Furthermore two temperature regimes of oxidation separated by an intermediate regime where only little oxidation takes place exist at residence times of 140 ms, if NO is the only nitrogen oxide initially present. The results were explained...

  9. Oxidative decarboxylation of levulinic acid by cupric oxides.

    Science.gov (United States)

    Gong, Yan; Lin, Lu; Shi, Jianbin; Liu, Shijie

    2010-11-05

    In this paper, cupric oxides was found to effectively oxidize levulinic acid (LA) and lead to the decarboxylation of levulinic acid to 2-butanone. The effects of cupric oxide dosage, reaction time and initial pH value were investigated in batch experiments and a plausible mechanism was proposed. The results showed that LA decarboxylation over cupric oxides at around 300 °C under acidic conditions produced the highest yield of butanone (67.5%). In order to elucidate the catalytic activity of cupric oxides, XRD, AFM, XPS and H(2)-TPR techniques was applied to examine their molecular surfaces and their effects on the reaction process.

  10. The aqueous chemistry of oxides

    CERN Document Server

    Bunker, Bruce C

    2016-01-01

    The Aqueous Chemistry of Oxides is a comprehensive reference volume and special topics textbook that explores all of the major chemical reactions that take place between oxides and aqueous solutions. The book highlights the enormous impact that oxide-water reactions have in advanced technologies, materials science, geochemistry, and environmental science.

  11. (VI) oxide in acetic acid

    African Journals Online (AJOL)

    The oxidation of cyclohexene by chromium (VI) oxide in aqueous and acetic media was studied. The reaction products were analysed using infra red (IR) and gas chromatography coupled with mass (GC/MS) spectroscopy. The major products of the oxidation reaction in acetic acid medium were cyclohexanol, ...

  12. Assessment of the role of α-lipoic acid against the oxidative stress of induced iron overload

    Directory of Open Access Journals (Sweden)

    Yasser F. Ali

    2015-01-01

    Full Text Available This work was aimed to study the protective role of α-lipoic acid against the oxidative damage of induced iron overload. Iron (Fe overload is a complication of the treatment, by chronic transfusion, of a number of genetic diseases associated with inadequate red cell production (anemias and of other genetic diseases that lead to excessive iron absorption from the diet. Male rats were injected ip with 5 mg/kg body weight ferrous sulfate for 50 days. The animals were injected ip with α-lipoic acid 20 mg per kg body weight for 21 days. Serum iron, Total Iron Binding Capacity (TIBC, Malonyldialdehyde (MDA, Electron paramagnetic resonance (EPR spectroscopy, UV-visible absorption spectrum of hemoglobin and osmotic fragility were studied. Results showed significant increase in serum iron, total iron binding capacity, and malonyldialdehyde levels in iron-loaded rats. Treatment with lipoic acid (LA resulted in decreasing serum iron and TIBC levels by 47%and 29% respectively. At the same time the lipoic acid decreased the level of the MDA in liver, brain and plasma by 54%, 42% and 74% respectively. Also LA diminished the effect of iron-induced free radicals on erythrocyte membrane integrity; it decreased the elevated average osmotic fragility and decreased the elevated rate of hemolysis. Results from UV-visible spectrophotometric measurement of hemoglobin revealed that no oxidative changes of hemoglobin occurred in iron-loaded rats. EPR spectra showed increased in non-heme ferric ions Fe+3 and free radicals in iron-loaded rats. Whereas the injection of the lipoic acid leads to decreased in such toxic result. In conclusion, these observations suggested that lipoic acid might be a beneficial antioxidant that can be effective for limiting damage from oxidative stress of iron overload.

  13. The production of iron oxide during peridotite serpentinization: Influence of pyroxene

    Directory of Open Access Journals (Sweden)

    Ruifang Huang

    2017-11-01

    Full Text Available Serpentinization produces molecular hydrogen (H2 that can support communities of microorganisms in hydrothermal fields; H2 results from the oxidation of ferrous iron in olivine and pyroxene into ferric iron, and consequently iron oxide (magnetite or hematite forms. However, the mechanisms that control H2 and iron oxide formation are poorly constrained. In this study, we performed serpentinization experiments at 311 °C and 3.0 kbar on olivine (with <5% pyroxene, orthopyroxene, and peridotite. The results show that serpentine and iron oxide formed when olivine and orthopyroxene individually reacted with a saline starting solution. Olivine-derived serpentine had a significantly lower FeO content (6.57 ± 1.30 wt.% than primary olivine (9.86 wt.%, whereas orthopyroxene-derived serpentine had a comparable FeO content (6.26 ± 0.58 wt.% to that of primary orthopyroxene (6.24 wt.%. In experiments on peridotite, olivine was replaced by serpentine and iron oxide. However, pyroxene transformed solely to serpentine. After 20 days, olivine-derived serpentine had a FeO content of 8.18 ± 1.56 wt.%, which was significantly higher than that of serpentine produced in olivine-only experiments. By contrast, serpentine after orthopyroxene had a slightly higher FeO content (6.53 ± 1.01 wt.% than primary orthopyroxene. Clinopyroxene-derived serpentine contained a significantly higher FeO content than its parent mineral. After 120 days, the FeO content of olivine-derived serpentine decreased significantly (5.71 ± 0.35 wt.%, whereas the FeO content of orthopyroxene-derived serpentine increased (6.85 ± 0.63 wt.% over the same period. This suggests that iron oxide preferentially formed after olivine serpentinization. Pyroxene in peridotite gained some Fe from olivine during the serpentinization process, which may have led to a decrease in iron oxide production. The correlation between FeO content and SiO2 or Al2O3 content in olivine- and

  14. Model catalytic oxidation studies using supported monometallic and heterobimetallic oxides

    Energy Technology Data Exchange (ETDEWEB)

    Ekerdt, J.G.

    1992-02-03

    This research program is directed toward a more fundamental understanding of the effects of catalyst composition and structure on the catalytic properties of metal oxides. Metal oxide catalysts play an important role in many reactions bearing on the chemical aspects of energy processes. Metal oxides are the catalysts for water-gas shift reactions, methanol and higher alcohol synthesis, isosynthesis, selective catalytic reduction of nitric oxides, and oxidation of hydrocarbons. A key limitation to developing insight into how oxides function in catalytic reactions is in not having precise information of the surface composition under reaction conditions. To address this problem we have prepared oxide systems that can be used to study cation-cation effects and the role of bridging (-O-) and/or terminal (=O) surface oxygen anion ligands in a systematic fashion. Since many oxide catalyst systems involve mixtures of oxides, we selected a model system that would permit us to examine the role of each cation separately and in pairwise combinations. Organometallic molybdenum and tungsten complexes were proposed for use, to prepare model systems consisting of isolated monomeric cations, isolated monometallic dimers and isolated bimetallic dimers supported on silica and alumina. The monometallic and bimetallic dimers were to be used as models of more complex mixed- oxide catalysts. Our current program was to develop the systems and use them in model oxidation reactions.

  15. Aerobic Oxidations of Light Alkanes over Solid Metal Oxide Catalysts.

    Science.gov (United States)

    Grant, Joseph T; Venegas, Juan M; McDermott, William P; Hermans, Ive

    2017-11-07

    Heterogeneous metal oxide catalysts are widely studied for the aerobic oxidations of C 1 -C 4 alkanes to form olefins and oxygenates. In this review, we outline the properties of supported metal oxides, mixed-metal oxides, and zeolites and detail their most common applications as catalysts for partial oxidations of light alkanes. By doing this we establish similarities between different classes of metal oxides and identify common themes in reaction mechanisms and research strategies for catalyst improvement. For example, almost all partial alkane oxidations, regardless of the metal oxide, follow Mars-van Krevelen reaction kinetics, which utilize lattice oxygen atoms to reoxidize the reduced metal centers while the gaseous O 2 reactant replenishes these lattice oxygen vacancies. Many of the most-promising metal oxide catalysts include V 5+ surface species as a necessary constituent to convert the alkane. Transformations involving sequential oxidation steps (i.e., propane to acrylic acid) require specific reaction sites for each oxidation step and benefit from site isolation provided by spectator species. These themes, and others, are discussed in the text.

  16. Chaperones, but not oxidized proteins, are ubiquitinated after oxidative stress

    DEFF Research Database (Denmark)

    Kästle, Marc; Reeg, Sandra; Rogowska-Wrzesinska, Adelina

    2012-01-01

    After oxidative stress proteins which are oxidatively modified are degraded by the 20S proteasome. However, several studies documented an enhanced ubiquitination of yet unknown proteins. Since ubiqutination is a prerequisite for degradation by the 26S proteasome in an ATP-dependent manner...... this raises the question whether these proteins are also oxidized and, if not, what proteins need to be ubiquitinated and degraded after oxidative conditions. By determination of oxidized- and ubiquitinated proteins we demonstrate here that most oxidized proteins are not preferentially ubiquitinated. However......, we were able to confirm an increase of ubiquitinated proteins 16h upon oxidative stress. Therefore, we isolated ubiquitinated proteins from hydrogen peroxide treated cells, as well as from control and lactacystin, an irreversible proteasome inhibitor, treated cells, and identified some...

  17. Iron oxide surfaces

    Science.gov (United States)

    Parkinson, Gareth S.

    2016-03-01

    The current status of knowledge regarding the surfaces of the iron oxides, magnetite (Fe3O4), maghemite (γ-Fe2O3), haematite (α-Fe2O3), and wüstite (Fe1-xO) is reviewed. The paper starts with a summary of applications where iron oxide surfaces play a major role, including corrosion, catalysis, spintronics, magnetic nanoparticles (MNPs), biomedicine, photoelectrochemical water splitting and groundwater remediation. The bulk structure and properties are then briefly presented; each compound is based on a close-packed anion lattice, with a different distribution and oxidation state of the Fe cations in interstitial sites. The bulk defect chemistry is dominated by cation vacancies and interstitials (not oxygen vacancies) and this provides the context to understand iron oxide surfaces, which represent the front line in reduction and oxidation processes. Fe diffuses in and out from the bulk in response to the O2 chemical potential, forming sometimes complex intermediate phases at the surface. For example, α-Fe2O3 adopts Fe3O4-like surfaces in reducing conditions, and Fe3O4 adopts Fe1-xO-like structures in further reducing conditions still. It is argued that known bulk defect structures are an excellent starting point in building models for iron oxide surfaces. The atomic-scale structure of the low-index surfaces of iron oxides is the major focus of this review. Fe3O4 is the most studied iron oxide in surface science, primarily because its stability range corresponds nicely to the ultra-high vacuum environment. It is also an electrical conductor, which makes it straightforward to study with the most commonly used surface science methods such as photoemission spectroscopies (XPS, UPS) and scanning tunneling microscopy (STM). The impact of the surfaces on the measurement of bulk properties such as magnetism, the Verwey transition and the (predicted) half-metallicity is discussed. The best understood iron oxide surface at present is probably Fe3O4(100); the structure is

  18. Electrorheology of graphene oxide.

    Science.gov (United States)

    Zhang, Wen Ling; Liu, Ying Dan; Choi, Hyoung Jin; Kim, Sang Guk

    2012-04-01

    Novel polarizable graphene oxide (GO) particles with oxidized groups on their edge and basal planes were prepared by a modified Hummers method, and their electro-responsive electrorheological (ER) characteristics when dispersed in silicone oil were examined with and without an electric field applied. The fibrillation phenomenon of this GO-based electro-responsive fluid was also observed via an optical microscope under an applied electric field. Both flow curves and dielectric spectra of the ER fluid were measured using a rotational rheometer and a LCR meter, respectively. Its viscoelastic properties of both storage and loss moduli were also examined using a vertical oscillation rheometer equipped with a high voltage generator, finding that the GO-based smart ER system behaves as a viscoelastic material under an applied electric field.

  19. Thin Solid Oxide Cell

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention relates to a thin and in principle unsupported solid oxide cell, comprising at least a porous anode layer, an electrolyte layer and a porous cathode layer, wherein the anode layer and the cathode layer comprise an electrolyte material, at least one metal and a catalyst...... material, and wherein the overall thickness of the thin reversible cell is about 150 [mu]m or less, and to a method for producing same. The present invention also relates to a thin and in principle unsupported solid oxide cell, comprising at least a porous anode layer, an electrolyte layer and a porous...... cathode layer, wherein the anode layer and the cathode layer comprise an electrolyte material and a catalyst material, wherein the electrolyte material is doper zirconia, and wherein the overall thickness of the thin reversible cell is about 150 [mu]m or less, and to a method for producing same...

  20. Defects at oxide surfaces

    CERN Document Server

    Thornton, Geoff

    2015-01-01

    This book presents the basics and characterization of defects at oxide surfaces. It provides a state-of-the-art review of the field, containing information to the various types of surface defects, describes analytical methods to study defects, their chemical activity and the catalytic reactivity of oxides. Numerical simulations of defective structures complete the picture developed. Defects on planar surfaces form the focus of much of the book, although the investigation of powder samples also form an important part. The experimental study of planar surfaces opens the possibility of applying the large armoury of techniques that have been developed over the last half-century to study surfaces in ultra-high vacuum. This enables the acquisition of atomic level data under well-controlled conditions, providing a stringent test of theoretical methods. The latter can then be more reliably applied to systems such as nanoparticles for which accurate methods of characterization of structure and electronic properties ha...

  1. Deactivation of Oxidation Catalysts

    Science.gov (United States)

    1991-05-01

    been observed to decrease CO oxidation even at 500TC ( Farrauto and Wedding, 1973, p. 254) by a sulfate formation mechanism, it is likely that the...sulfated CoO, in the study of Farrauto and Wedding (1973) and that no deactivation was observed in the previously discussed study by Pope et al...This is attributed to the adsorption of HO on the catalyst surface which competes with the adsorption of ethanol. Farrauto and Wedding (1973) studied

  2. Radiolytic graphite oxidation revisited

    International Nuclear Information System (INIS)

    Minshall, P.C.; Sadler, I.A.; Wickham, A.J.

    1996-01-01

    The importance of radiolytic oxidation in graphite-moderated CO 2 -cooled reactors has long been recognised, especially in the Advanced Gas-Cooled Reactors where potential rates are higher because of the higher gas pressure and ratings than the earlier Magnox designs. In all such reactors, the rate of oxidation is partly inhibited by the CO produced in the reaction and, in the AGR, further reduced by the deliberate addition of CH 4 . Significant roles are also played by H 2 and H 2 O. This paper reviews briefly the mechanisms of these processes and the data on which they are based. However, operational experience has demonstrated that these basic principles are unsatisfactory in a number of respects. Gilsocarbon graphites produced by different manufacturers have demonstrated a significant difference in oxidation rate despite a similar specification and apparent equivalence in their pore size and distribution, considered to be the dominant influence on oxidation rate for a given coolant-gas composition. Separately, the inhibiting influence of CH 4 , which for many years had been considered to arise from the formation of a sacrificial deposit on the pore walls, cannot adequately be explained by the actual quantities of such deposits found in monitoring samples which frequently contain far less deposited carbon than do samples from Magnox reactors where the only source of such deposits is the CO. The paper also describes the current status of moderator weight-loss predictions for Magnox and AGR Moderators and the validation of the POGO and DIFFUSE6 codes respectively. 2 refs, 5 figs

  3. Nitrous Oxide Explosive Hazards

    Science.gov (United States)

    2008-05-01

    JC, Departement d’anesthesie- reanimation, CHU Angers, 49033 cedex 01, Angers, France , Ann Fr Anesth Reanim, pp 366-8, April 22, 2003. 8. “Some...Krisjansons, Doren E. Bollinger , and Rudolph Edse, ARL 62-431. September 1962. 21. “Detonability of Nitrous Oxide at Elevated Initial Pressures and...Temperatures”, James A Laughrey, Loren E. Bollinger , Rudolph Edse, ARL 62-432, September 1962. 22. “Investigation of Decomposition Characteristics

  4. Oxidative stability of polyaniline

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Exnerová, Milena; Morávková, Zuzana; Trchová, Miroslava; Hromádková, Jiřina; Prokeš, J.

    2012-01-01

    Roč. 97, č. 6 (2012), s. 1026-1033 ISSN 0141-3910 R&D Projects: GA ČR GA202/09/1626; GA ČR GAP205/12/0911 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : polyaniline * nanotubes * oxidation stability Subject RIV: BK - Fluid Dynamics Impact factor: 2.770, year: 2012

  5. Iron and oxygen isotope fractionation during iron UV photo-oxidation: Implications for early Earth and Mars

    Science.gov (United States)

    Nie, Nicole X.; Dauphas, Nicolas; Greenwood, Richard C.

    2017-01-01

    Banded iron formations (BIFs) contain appreciable amounts of ferric iron (Fe3+). The mechanism by which ferrous iron (Fe2+) was oxidized into Fe3+ in an atmosphere that was globally anoxic is highly debated. Of the three scenarios that have been proposed to explain BIF formation, photo-oxidation by UV photons is the only one that does not involve life (the other two are oxidation by O2 produced by photosynthesis, and anoxygenic photosynthesis whereby Fe2+ is directly used as electron donor in place of water). We experimentally investigated iron and oxygen isotope fractionation imparted by iron photo-oxidation at a pH of 7.3. The iron isotope fractionation between precipitated Fe3+-bearing lepidocrocite and dissolved Fe2+ follows a Rayleigh distillation with an instantaneous 56Fe/54Fe fractionation factor of + 1.2 ‰. Such enrichment in the heavy isotopes of iron is consistent with the values measured in BIFs. We also investigated the nature of the mass-fractionation law that governs iron isotope fractionation in the photo-oxidation experiments (i.e., the slope of the δ56Fe-δ57Fe relationship). The experimental run products follow a mass-dependent law corresponding to the high-T equilibrium limit. The fact that a ∼3.8 Gyr old BIF sample (IF-G) from Isua (Greenland) falls on the same fractionation line confirms that iron photo-oxidation in the surface layers of the oceans was a viable pathway to BIF formation in the Archean, when the atmosphere was largely transparent to UV photons. Our experiments allow us to estimate the quantum yield of the photo-oxidation process (∼0.07 iron atom oxidized per photon absorbed). This yield is used to model iron oxidation on early Mars. As the photo-oxidation proceeds, the aqueous medium becomes more acidic, which slows down the reaction by changing the speciation of iron to species that are less efficient at absorbing UV-photons. Iron photo-oxidation in centimeter to meter-deep water ponds would take months to years to

  6. Continuous sulfidogenic wastewater treatment with iron sulfide sludge oxidation and recycle.

    Science.gov (United States)

    Deng, Dongyang; Lin, Lian-Shin

    2017-05-01

    This study evaluated the technical feasibility of packed-bed sulfidogenic bioreactors dosed with ferrous chloride for continuous wastewater treatment over a 450-day period. In phase I, the bioreactors were operated under different combinations of carbon, iron, and sulfate mass loads without sludge recycling to identify optimal treatment conditions. A COD/sulfate mass ratio of 2 and a Fe/S molar ratio of 1 yielded the best treatment performance with COD oxidation rate of 786 ± 82 mg/(L⋅d), which resulted in 84 ± 9% COD removal, 94 ± 6% sulfate reduction, and good iron retention (99 ± 1%) under favorable pH conditions (6.2-7.0). In phase II, the bioreactors were operated under this chemical load combination over a 62-day period, during which 7 events of sludge collection, oxidation, and recycling were performed. The collected sludge materials contained both inorganic and organic matter with FeS and FeS 2 as the main inorganic constituents. In each event, the sludge materials were oxidized in an oxidizing basin before recycling to mix with the wastewater influent. Sludge recycling yielded enhanced COD removal (90 ± 6% vs. 75 ± 7%), and better effluent quality in terms of pH (6.8 ± 0.1 vs. 6.5 ± 0.2), iron (0.7 ± 0.5 vs. 1.9 ± 1.7 mg/L), and sulfide-S (0.3 ± 0.1 vs. 0.4 ± 0.1 mg/L) removal compared to the baseline operation without sludge recycling during phase II. This process exhibited treatment stability with reasonable variations, and fairly consistent sludge content over long periods of operation under a range of COD/sulfate and Fe/S ratios without sludge recycling. The bioreactors were found to absorb recycling-induced changes efficiently without causing elevated suspended solids in the effluents. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Molecular theory of graphene oxide.

    Science.gov (United States)

    Sheka, Elena F; Popova, Nadezhda A

    2013-08-28

    Applied to graphene oxide, the molecular theory of graphene considers its oxide as a final product in the succession of polyderivatives related to a series of oxidation reactions involving different oxidants. The graphene oxide structure is created in the course of a stepwise computational synthesis of polyoxides of the (5,5) nanographene molecule governed by an algorithm that takes into account the molecule's natural radicalization due to the correlation of its odd electrons, the extremely strong influence of the structure on properties, and a sharp response of the molecule behavior on small actions of external factors. Taking these together, the theory has allowed for a clear, transparent and understandable explanation of the hot points of graphene oxide chemistry and suggesting reliable models of both chemically produced and chemically reduced graphene oxides.

  8. Alkane oxidation by osmium tetroxide.

    Science.gov (United States)

    Bales, Brian C; Brown, Peter; Dehestani, Ahmad; Mayer, James M

    2005-03-09

    Aqueous alkaline OsO4 at 85 degrees C oxidizes saturated alkanes, including primary, secondary, and tertiary C-H bonds. Isobutane affords tert-butanol in quantitative yield based on consumed OsO4. Cyclohexane is oxidized to a mixture of adipate and succinate. Ethane and propane are oxidized to acetate, which itself is further oxidized under the reaction conditions. A few turnovers of isobutane oxidation have been accomplished using NaIO4 as the terminal oxidant. The alkane oxidation is an example of ligand accelerated catalysis, as hydroxide binding to OsO4 is required for reaction. A concerted mechanism involving [3+2] addition of a C-H bond to two oxo groups of OsO4(OH)- is suggested, analogous to the pathways for dihydroxylation of alkenes by OsO4(L) and for addition of H2 to OsO4(L).

  9. Oxidation process of cadmium sulfide

    International Nuclear Information System (INIS)

    Hashimoto, Koshiro; Toda, Yoshitomo; Sato, Takayori

    1977-01-01

    Complicated thermogravimetric curve was observed on oxidation process of cadmium sulfide precipitate in air. Phases of various oxidation stage were identified by X-ray diffraction method. Cadmium sulfide was first oxidized to cadmium oxide at 400 0 C, while the successive reaction with sulfur dioxide and oxygen gases gave rise to cadmium sulfate. The phases such as 2 CdS. CdSO 4 , Cd 3 SO 6 and β-CdSO 4 appeared during the oxidation process up to 1100 0 C, at which all the particles were converted into cadmium oxide at 1100 0 C. Cadmium sulfide kept in nitrogen gas above 700 0 C was directly converted into cadmium oxide when oxygen gas was introduced into the furnace. (auth.)

  10. Expression of Critical Sulfur- and Iron-Oxidation Genes and the Community Dynamics During Bioleaching of Chalcopyrite Concentrate by Moderate Thermophiles.

    Science.gov (United States)

    Zhou, Dan; Peng, Tangjian; Zhou, Hongbo; Liu, Xueduan; Gu, Guohua; Chen, Miao; Qiu, Guanzhou; Zeng, Weimin

    2015-07-01

    Sulfate adenylyltransferase gene and 4Fe-4S ferredoxin gene are the key genes related to sulfur and iron oxidations during bioleaching system, respectively. In order to better understand the bioleaching and microorganism synergistic mechanism in chalcopyrite bioleaching by mixed culture of moderate thermophiles, expressions of the two energy metabolism genes and community dynamics of free and attached microorganisms were investigated. Specific primers were designed for real-time quantitative PCR to study the expression of these genes. Real-time PCR results showed that sulfate adenylyltransferase gene was more highly expressed in Sulfobacillus thermosulfidooxidans than that in Acidithiobacillus caldus, and expression of 4Fe-4S ferredoxin gene was higher in Ferroplasma thermophilum than that in S. thermosulfidooxidans and Leptospirillum ferriphilum. The results indicated that in the bioleaching system of chalcopyrite concentrate, sulfur and iron oxidations were mainly performed by S. thermosulfidooxidans and F. thermophilum, respectively. The community dynamics results revealed that S. thermosulfidooxidans took up the largest proportion during the whole period, followed by F. thermophilum, A. caldus, and L. ferriphilum. The CCA analysis showed that 4Fe-4S ferredoxin gene expression was mainly affected (positively correlated) by high pH and elevated concentration of ferrous ion, while no factor was observed to prominently influence the expression of sulfate adenylyltransferase gene.

  11. In vitro and in vivo evidences that antioxidant action contributes to the neuroprotective effects of the neuronal nitric oxide synthase and monoamine oxidase-B inhibitor, 7-nitroindazole.

    Science.gov (United States)

    Thomas, Bobby; Saravanan, Karuppagounder S; Mohanakumar, Kochupurackal P

    2008-05-01

    The neuronal nitric oxide synthase (nNOS) inhibitor, 7-nitroindazole (7-NI) is neuroprotective against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonism. Monoamine oxidase (MAO)-B inhibitory action partially contributes to this effect. We tested the hypothesis that 7-NI could be a powerful hydroxyl radical (OH) scavenger, and interferes with oxidative stress caused by MPTP. We measured OH, reduced glutathione (GSH), as well as superoxide dismutase (SOD) and catalase activities in the nucleus caudatus putamen and substantia nigra of Balb/c mice following MPTP and/or 7-NI administration. The nNOS inhibitor caused dose-dependent inhibition in the production of OH in (i) Fenton-like reaction employing ferrous citrate in a cell-free system in test tubes, (ii) in isolated mitochondrial preparation in presence of MPP+, and (iii) in the striatum of mice systemically treated with MPTP. An MPTP-induced depletion of GSH in both the nuclei was blocked by 7-NI, which was dose-dependent (10-50mg/kg), but independent of MAO-B inhibition. The nNOS-mediated recovery of GSH paralleled attenuation of MPTP-induced depletion of striatal dopamine. MPTP-induced increase in the activities of striatal or nigral SOD and catalase were significantly attenuated by 7-NI treatment. These results suggest potent antioxidant action of 7-NI in its neuroprotective effects against MPTP-induced neurotoxicity.

  12. The role of oxidative debris on graphene oxide films.

    Science.gov (United States)

    López-Díaz, David; Velázquez, Maria Mercedes; Blanco de La Torre, Santiago; Pérez-Pisonero, Ana; Trujillano, Raquel; García Fierro, José Luis; Claramunt, Sergi; Cirera, Albert

    2013-12-02

    We study the effect of oxidative impurities on the properties of graphene oxide and on the graphene oxide Langmuir-Blodgett films (LB). The starting material was grupo Antolín nanofibers (GANF) and the oxidation process was a modified Hummers method to obtain highly oxidized graphene oxide. The purification procedure reported in this work eliminated oxidative impurities decreasing the thickness of the nanoplatelets. The purified material thus obtained presents an oxidation degree similar to that achieved by chemical reduction of the graphite oxide. The purified and non-purified graphene oxides were deposited onto silicon by means of a Langmuir-Blodgett (LB) methodology. The morphology of the LB films was analyzed by field emission scanning microscopy (FE-SEM) and micro-Raman spectroscopy. Our results show that the LB films built by transferring Langmuir monolayers at the liquid-expanded state of the purified material are constituted by close-packed and non-overlapped nanoplatelets. The isotherms of the Langmuir monolayer precursor of the LB films were interpreted according to the Volmer's model. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. A novel acidophilic, thermophilic iron and sulfur-oxidizing archaeon isolated from a hot spring of tengchong, yunnan, China

    Directory of Open Access Journals (Sweden)

    Jiannan Ding

    2011-06-01

    Full Text Available A novel thermoacidophilic iron and sulfur-oxidizing archaeon, strain YN25, was isolated from an in situ enriched acid hot spring sample collected in Yunnan, China. Cells were irregular cocci, about 0.9-1.02 µm×1.0-1.31 µm in the medium containing elemental sulfur and 1.5-2.22 µm×1.8-2.54 µm in ferrous sulfate medium. The ranges of growth and pH were 50-85 (optimum 65 and pH 1.0-6.0 (optimum 1.5-2.5. The acidophile was able to grow heterotrophically on several organic substrates, including various monosaccharides, alcohols and amino acids, though the growth on single substrate required yeast extract as growth factor. Growth occurred under aerobic conditions or via anaerobic respiration using elemental sulfur as terminal electron acceptor. Results of morphology, physiology, fatty acid analysis and analysis based on 16S rRNA gene sequence indicated that the strain YN25 should be grouped in the species Acidianus manzaensis. Bioleaching experiments indicated that this strain had excellent leaching capacity, with a copper yielding ratio up to 79.16% in 24 d. The type strain YN25 was deposited in China Center for Type Culture Collection (=CCTCCZNDX0050.

  14. The competing oxide and sub-oxide formation in metal-oxide molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, Patrick; Bierwagen, Oliver [Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, D-10117 Berlin (Germany)

    2015-02-23

    The hetero-epitaxial growth of the n-type semiconducting oxides β-Ga{sub 2}O{sub 3}, In{sub 2}O{sub 3}, and SnO{sub 2} on c- and r-plane sapphire was performed by plasma-assisted molecular beam epitaxy. The growth-rate and desorbing flux from the substrate were measured in-situ under various oxygen to metal ratios by laser reflectometry and quadrupole mass spectrometry, respectively. These measurements clarified the role of volatile sub-oxide formation (Ga{sub 2}O, In{sub 2}O, and SnO) during growth, the sub-oxide stoichiometry, and the efficiency of oxide formation for the three oxides. As a result, the formation of the sub-oxides decreased the growth-rate under metal-rich growth conditions and resulted in etching of the oxide film by supplying only metal flux. The flux ratio for the exclusive formation of the sub-oxide (e.g., the p-type semiconductor SnO) was determined, and the efficiency of oxide formation was found to be the highest for SnO{sub 2}, somewhat lower for In{sub 2}O{sub 3}, and the lowest for Ga{sub 2}O{sub 3}. Our findings can be generalized to further oxides that possess related sub-oxides.

  15. The oxidative hypothesis of senescence

    Directory of Open Access Journals (Sweden)

    Gilca M

    2007-01-01

    Full Text Available The oxidative hypothesis of senescence, since its origin in 1956, has garnered significant evidence and growing support among scientists for the notion that free radicals play an important role in ageing, either as "damaging" molecules or as signaling molecules. Age-increasing oxidative injuries induced by free radicals, higher susceptibility to oxidative stress in short-lived organisms, genetic manipulations that alter both oxidative resistance and longevity and the anti-ageing effect of caloric restriction and intermittent fasting are a few examples of accepted scientific facts that support the oxidative theory of senescence. Though not completely understood due to the complex "network" of redox regulatory systems, the implication of oxidative stress in the ageing process is now well documented. Moreover, it is compatible with other current ageing theories (e.g., those implicating the mitochondrial damage/mitochondrial-lysosomal axis, stress-induced premature senescence, biological "garbage" accumulation, etc. This review is intended to summarize and critically discuss the redox mechanisms involved during the ageing process: sources of oxidant agents in ageing (mitochondrial -electron transport chain, nitric oxide synthase reaction- and non-mitochondrial- Fenton reaction, microsomal cytochrome P450 enzymes, peroxisomal β -oxidation and respiratory burst of phagocytic cells, antioxidant changes in ageing (enzymatic- superoxide dismutase, glutathione-reductase, glutathion peroxidase, catalase- and non-enzymatic glutathione, ascorbate, urate, bilirubine, melatonin, tocopherols, carotenoids, ubiquinol, alteration of oxidative damage repairing mechanisms and the role of free radicals as signaling molecules in ageing.

  16. The 2016 oxide electronic materials and oxide interfaces roadmap

    International Nuclear Information System (INIS)

    Lorenz, M; Grundmann, M; Ramachandra Rao, M S; Mukherjee, J; Priyadarshini, M; Venkatesan, T; Fortunato, E; Barquinha, P; Branquinho, R; Salgueiro, D; Martins, R; Carlos, E; Liu, A; Shan, F K; Boschker, H; DasGupta, N; Rogers, D J; Teherani, F H; Sandana, E V; Bove, P

    2016-01-01

    Oxide electronic materials provide a plethora of possible applications and offer ample opportunity for scientists to probe into some of the exciting and intriguing phenomena exhibited by oxide systems and oxide interfaces. In addition to the already diverse spectrum of properties, the nanoscale form of oxides provides a new dimension of hitherto unknown phenomena due to the increased surface-to-volume ratio. Oxide electronic materials are becoming increasingly important in a wide range of applications including transparent electronics, optoelectronics, magnetoelectronics, photonics, spintronics, thermoelectrics, piezoelectrics, power harvesting, hydrogen storage and environmental waste management. Synthesis and fabrication of these materials, as well as processing into particular device structures to suit a specific application is still a challenge. Further, characterization of these materials to understand the tunability of their properties and the novel properties that evolve due to their nanostructured nature is another facet of the challenge. The research related to the oxide electronic field is at an impressionable stage, and this has motivated us to contribute with a roadmap on ‘oxide electronic materials and oxide interfaces’. This roadmap envisages the potential applications of oxide materials in cutting edge technologies and focuses on the necessary advances required to implement these materials, including both conventional and novel techniques for the synthesis, characterization, processing and fabrication of nanostructured oxides and oxide-based devices. The contents of this roadmap will highlight the functional and correlated properties of oxides in bulk, nano, thin film, multilayer and heterostructure forms, as well as the theoretical considerations behind both present and future applications in many technologically important areas as pointed out by Venkatesan. The contributions in this roadmap span several thematic groups which are represented by

  17. Solid oxide fuel cells fueled with reducible oxides

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, Steven S.; Fan, Liang Shih

    2018-01-09

    A direct-electrochemical-oxidation fuel cell for generating electrical energy includes a cathode provided with an electrochemical-reduction catalyst that promotes formation of oxygen ions from an oxygen-containing source at the cathode, a solid-state reduced metal, a solid-state anode provided with an electrochemical-oxidation catalyst that promotes direct electrochemical oxidation of the solid-state reduced metal in the presence of the oxygen ions to produce electrical energy, and an electrolyte disposed to transmit the oxygen ions from the cathode to the solid-state anode. A method of operating a solid oxide fuel cell includes providing a direct-electrochemical-oxidation fuel cell comprising a solid-state reduced metal, oxidizing the solid-state reduced metal in the presence of oxygen ions through direct-electrochemical-oxidation to obtain a solid-state reducible metal oxide, and reducing the solid-state reducible metal oxide to obtain the solid-state reduced metal.

  18. Wet oxidation catalyzed by ruthenium supported on cerium (IV) oxides

    International Nuclear Information System (INIS)

    Imamura, S.; Fukuda, I.; Ishida, S.

    1988-01-01

    The activity of precious meta catalysts in the wet oxidation of organic compounds was investigated. Ruthenium was the most active catalyst among the precious metals examined, and cerium (IV) oxide was the most effective support. The Ru/Ce catalyst rivaled homogeneous copper catalyst, which is used in the practical wastewater treatment, for the oxidation of n-propyl alcohol, n-butyl alcohol, phenol, acetamide, poly (propylene glycol), and acetic acid. In addition, it was especially effective for the oxidation of some compounds with high oxygen content such as poly (ethylene glycol), ethylene glycol, formaldehyde, and formic acid

  19. Protein oxidation and ageing

    DEFF Research Database (Denmark)

    Linton, S; Davies, Michael Jonathan; Dean, R T

    2001-01-01

    of redox-active metal ions that could catalyse oxidant formation. As a result of this decrease in antioxidant defences, and increased rate of ROS formation, it is possible that the impact of ROS increases with age. ROS are known to oxidise biological macromolecules, with proteins an important target....... If the argument that the impact of ROS increases with age is true, then proteins would be expected to accumulate oxidised materials with age, and the rate of such accumulation should increase with time, reflecting impaired inefficiency of homeostasis. Here we review the evidence for the accumulation of oxidised......, or modified, extra- and intra-cellular proteins in vivo....

  20. Oxidation in Enceladus' Ocean

    Science.gov (United States)

    Ray, C.; Waite, J. H., Jr.; Glein, C.; Teolis, B. D.

    2017-12-01

    The detection of molecular hydrogen in the plume of Saturn's icy moon Enceladus reports that there is positive chemical affinity for methanogenesis, the reaction of hydrogen with carbon dioxide to form methane and water [Waite et al., 2017]. Methanogenesis, however, is just one of many possible metabolic pathways that could be utilized. While some of the oxidants involved in these metabolic pathways have already been detected in the plume (i.e. carbon dioxide), sulfate, which could play an important role in several of these reactions, has not yet been observed. To constrain the amount of sulfate and other oxidants that could be present to support these metabolisms, we present a geochemical model of Enceladus' ocean based on detections made by the Cassini INMS instrument [Waite et. al, 2017]. We use a model of radiolysis on the surface of Enceladus to estimate the amount of molecular oxygen (O2) contained in the ice. We calculate the delivery rate of O2 from the surface ice to the ocean using previous estimates of the rate of ice deposition on the south polar region [Kempf et al., 2010], and the meteoritic gardening rate for the older surface of the moon. Assuming this activity has occurred over 4.5 billion years, we obtain an upper limit of > 1020 moles of O2 delivered to the ocean over Enceladus' lifetime. This large amount of oxygen could react with sulfides, reduced iron, or organic materials to produce sulfate, ferric oxyhydroxides, or carbon dioxide/carboxylic acids, respectively. We calculate upper limits on the amounts of these materials using a mineralogical model of Enceladus' core [Waite et al., 2017]. We find that the abiotic oxidation of pyrrhotite, which is the most likely pathway for sulfate production, could yield a sulfate concentration > 4 mol/(kg H2O). We suggest that oxidants should be abundant in the ocean and plume unless they are being consumed by life, the rate of ice deposition on the surface is much smaller than what has been predicted, or