WorldWideScience

Sample records for iron reduction related

  1. Reduction of body iron in HFE-related haemochromatosis and moderate iron overload (Mi-Iron): a multicentre, participant-blinded, randomised controlled trial.

    Science.gov (United States)

    Ong, Sim Y; Gurrin, Lyle C; Dolling, Lara; Dixon, Jeanette; Nicoll, Amanda J; Wolthuizen, Michelle; Wood, Erica M; Anderson, Gregory J; Ramm, Grant A; Allen, Katrina J; Olynyk, John K; Crawford, Darrell; Ramm, Louise E; Gow, Paul; Durrant, Simon; Powell, Lawrie W; Delatycki, Martin B

    2017-12-01

    The iron overload disorder hereditary haemochromatosis is most commonly caused by HFE p.Cys282Tyr homozygosity. In the absence of results from any randomised trials, current evidence is insufficient to determine whether individuals with hereditary haemochromatosis and moderately elevated serum ferritin, should undergo iron reduction treatment. This trial aimed to establish whether serum ferritin normalisation in this population improved symptoms and surrogate biomarkers. This study was a multicentre, participant-blinded, randomised controlled trial done at three centres in Australia. We enrolled people who were homozygous for HFE p.Cys282Tyr, aged between 18 and 70 years, with moderately elevated serum ferritin, defined as 300-1000 μg/L, and raised transferrin saturation. Participants were randomly assigned, via a computer-generated random number, to undergo either iron reduction by erythrocytapheresis (treatment group) or sham treatment by plasmapheresis (control group). Randomisation was stratified by baseline serum ferritin (cognitive subcomponent (-3·6, -5·9 to -1·3, p=0·0030), but not in the physical (-1·90 -4·5 to 0·63, p=0·14) and psychosocial (-0·54, -1·2 to 0·11, p=0·10) subcomponents. No serious adverse events occurred in either group. One participant in the control group had a vasovagal event and 17 participants (14 in the treatment group and three in the control group) had transient symptoms assessed as related to hypovolaemia. Mild citrate reactions were more common in the treatment group (32 events [25%] in 129 procedures) compared with the control group (one event [1%] in 93 procedures). To our knowledge, this study is the first to objectively assess the consequences of iron removal in individuals with hereditary haemochromatosis and moderately elevated serum ferritin. Our results suggest that serum ferritin normalisation by iron depletion could be of benefit for all individuals with hereditary haemochromatosis and elevated serum

  2. Microbial reduction of iron ore

    Science.gov (United States)

    Hoffmann, M.R.; Arnold, R.G.; Stephanopoulos, G.

    1989-11-14

    A process is provided for reducing iron ore by treatment with microorganisms which comprises forming an aqueous mixture of iron ore, microorganisms operable for reducing the ferric iron of the iron ore to ferrous iron, and a substrate operable as an energy source for the microbial reduction; and maintaining the aqueous mixture for a period of time and under conditions operable to effect the reduction of the ore. Preferably the microorganism is Pseudomonas sp. 200 and the reduction conducted anaerobically with a domestic wastewater as the substrate. An aqueous solution containing soluble ferrous iron can be separated from the reacted mixture, treated with a base to precipitate ferrous hydroxide which can then be recovered as a concentrated slurry. 11 figs.

  3. Microbial iron reduction related to metal speciation in mine waste at the former uranium mine in Ranstad

    International Nuclear Information System (INIS)

    Nejad, F.T.

    1998-02-01

    Mining activities in Ranstad uranium mine started in 1965 and ended in 1969. In 1988 the final restoration was discussed, and it was proposed to water-fill the open pit and cover the waste disposal area using the 'dry method'. Today the open pit has become a lake. Also some alum shale was placed on the land surface where it has been weathered by oxygen and water during 30 years. In 1994 it was observed that the color of the lake turned over to brown-red. Further studies showed increasing iron concentration in the lake and around the tailings area. For estimation of microbial iron reduction in the lake, three iron reducing bacteria were isolated from the water-filled open pit. For the enrichment process, water samples were inoculated in an anoxic enrichment medium. The isolates were able to reduce Fe(III) oxyhydroxide by oxidation of lactate as energy source. Growth of these strains was determined by production of a black precipitation of iron sulfide and was confirmed by estimation of total number of cells. Fe(III) reduction was monitored by measuring the accumulation of Fe(II) over time. Comparison of the 16S rRNA gene sequences of strains Tran-l, Tran-2, and Tran-3 with the EMBL data base showed 98.6% identity with Shewanella putrefaciens, 98.7% identity with Shewanella alga and 98.2% identity with Aeromonas salmonicida, respectively. S. putrefaciens strains have been isolated from many different environments, many of which are suboxic or anoxic. In addition to growing aerobically, S. putrefaciens can use Fe(III) as terminal electron acceptor under anaerobic conditions. To distinguish if the Fe(III) and/or organic compounds presence in weathered alum shale can be utilized by iron reducing bacteria isolated from the lake, reduction of Fe(III) coupled to the oxidation of organic compounds in sterile and non-sterile weathered alum shale was studied. The reduction of Fe(III) coupled to growth of bacteria on sterile and non-sterile shale was observed. Furthermore

  4. Microbial iron reduction related to metal speciation in mine waste at the former uranium mine in Ranstad

    Energy Technology Data Exchange (ETDEWEB)

    Nejad, F.T. [Goeteborg Univ. (Sweden). Dept. of General and Marine Microbiology

    1998-02-01

    Mining activities in Ranstad uranium mine started in 1965 and ended in 1969. In 1988 the final restoration was discussed, and it was proposed to water-fill the open pit and cover the waste disposal area using the `dry method`. Today the open pit has become a lake. Also some alum shale was placed on the land surface where it has been weathered by oxygen and water during 30 years. In 1994 it was observed that the color of the lake turned over to brown-red. Further studies showed increasing iron concentration in the lake and around the tailings area. For estimation of microbial iron reduction in the lake, three iron reducing bacteria were isolated from the water-filled open pit. For the enrichment process, water samples were inoculated in an anoxic enrichment medium. The isolates were able to reduce Fe(III) oxyhydroxide by oxidation of lactate as energy source. Growth of these strains was determined by production of a black precipitation of iron sulfide and was confirmed by estimation of total number of cells. Fe(III) reduction was monitored by measuring the accumulation of Fe(II) over time. Comparison of the 16S rRNA gene sequences of strains Tran-l, Tran-2, and Tran-3 with the EMBL data base showed 98.6% identity with Shewanella putrefaciens, 98.7% identity with Shewanella alga and 98.2% identity with Aeromonas salmonicida, respectively. S. putrefaciens strains have been isolated from many different environments, many of which are suboxic or anoxic. In addition to growing aerobically, S. putrefaciens can use Fe(III) as terminal electron acceptor under anaerobic conditions. To distinguish if the Fe(III) and/or organic compounds presence in weathered alum shale can be utilized by iron reducing bacteria isolated from the lake, reduction of Fe(III) coupled to the oxidation of organic compounds in sterile and non-sterile weathered alum shale was studied. The reduction of Fe(III) coupled to growth of bacteria on sterile and non-sterile shale was observed. Furthermore

  5. Iron absorption in relation to iron status

    International Nuclear Information System (INIS)

    Magnusson, B.; Bjoern-Rasmussen, E.; Hallberg, L.; Rossander, L.

    1981-01-01

    The absorption from a 3 mg dose of ferrous iron was measured in 250 male subjects. The absorption was related to the log concentration of serum ferritin in 186 subjects of whom 99 were regular blood donors (r= -0.76), and to bone marrow haemosiderin grading in 52 subjects with varying iron status. The purpose was to try and establish a percentage absorption from such a dose that is representative of subjects who are borderline iron deficient. This information is necessary for food iron absorption studies in order (1) to calculate the absorption of iron from the diet at a given iron status and (2) compare the absorption of iron from different meals studied in different groups of subjects by different investigarors. The results suggest that an absorption of about 40% of a 3 mg reference dose of ferrous iron is given in a fasting state, roughly corresponds to the absorption in borderline-iron-deficient subjects. The results indicate that this 40% absorption value corresponds to a serum ferritin level of 30 μg/l and that food iron absorption in a group of subjects should be expressed preferably as the absorption corresponding to a reference-dose absorption of 45%, or possibly a serum ferritin level of 30 μg/l. (author)

  6. Direct Reduction of Iron Ore

    Science.gov (United States)

    Small, M.

    1981-04-01

    In the search for a pure, available iron source, steelmakers are focusing their attention on Directly Reduced Iron (DRI). This material is produced by the reaction of a low gangue iron ore with a hydrocarbonaceous substance. Commercially, DRI is generated in four different reactors: shaft (moving-bed), rotary kiln, fluidized bed, and retort (fixed-bed). Annual worldwide production capacity approaches 33 million metric tons. Detailed assessments have been made of the uses of DRI, especially as a substitute for scrap in electric furnace (EF) steelmaking. DRI is generally of a quality superior to current grades of scrap, with steels produced more efficiently in the EF and containing lower levels of impurities. However, present economics favor EF steel production with scrap. But this situation could change within this decade because of a developing scarcity of good quality scrap.

  7. Suspension Hydrogen Reduction of Iron Oxide Concentrates

    Energy Technology Data Exchange (ETDEWEB)

    H.Y. Sohn

    2008-03-31

    The objective of the project is to develop a new ironmaking technology based on hydrogen and fine iron oxide concentrates in a suspension reduction process. The ultimate objective of the new technology is to replace the blast furnace and to drastically reduce CO2 emissions in the steel industry. The goals of this phase of development are; the performance of detailed material and energy balances, thermochemical and equilibrium calculations for sulfur and phosphorus impurities, the determination of the complete kinetics of hydrogen reduction and bench-scale testing of the suspension reduction process using a large laboratory flash reactor.

  8. Chemical Reduction Synthesis of Iron Aluminum Powders

    Science.gov (United States)

    Zurita-Méndez, N. N.; la Torre, G. Carbajal-De; Ballesteros-Almanza, L.; Villagómez-Galindo, M.; Sánchez-Castillo, A.; Espinosa-Medina, M. A.

    In this study, a chemical reduction synthesis method of iron aluminum (FeAl) nano-dimensional intermetallic powders is described. The process has two stages: a salt reduction and solvent evaporation by a heat treatment at 1100°C. The precursors of the synthesis are ferric chloride, aluminum foil chips, a mix of Toluene/THF in a 75/25 volume relationship, and concentrated hydrochloric acid as initiator of the reaction. The reaction time was 20 days, the product obtained was dried at 60 °C for 2 h and calcined at 400, 800, and 1100 °C for 4 h each. To characterize and confirm the obtained synthesis products, X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) techniques were used. The results of morphology and chemical characterization of nano-dimensional powders obtained showed a formation of agglomerated particles of a size range of approximately 150 nm to 1.0 μm. Composition of powders was identified as corundum (Al2O3), iron aluminide (FeAl3), and iron-aluminum oxides (Fe0. 53Al0. 47)2O3 phases. The oxide phases formation were associated with the reaction of atmospheric concentration-free oxygen during synthesis and sintering steps, reducing the concentration of the iron aluminum phase.

  9. Reduction experiment of iron scale by adding waste plastics.

    Science.gov (United States)

    Zhang, Chongmin; Chen, Shuwen; Miao, Xincheng; Yuan, Hao

    2009-01-01

    The special features of waste plastics in China are huge in total amount, various in type and dispersive in deposition. Therefore, it is necessary to try some new ways that are fit to Chinese situation for disposing waste plastics as metallurgical raw materials more effectively and flexibly. Owing to its high ferrous content and less impurity, the iron scale became ideal raw material to produce pure iron powder. One of the methods to produce pure iron powder is Hoganas Method, by which, after one or multistage of reduction steps, the iron scale can be reduced pure iron powder. However, combining utilization of waste plastics and iron powder production, a series of reduction experiments were arranged and investigated, which is hoped to take use of both thermal and chemical energy contained in waste plastics as well as to improve the reducing condition of iron scale, and hence to develop a new metallurgical way of disposing waste plastics. The results show that under these experimental conditions, the thermal-decomposition of water plastics can conduce to an increase of porosity in the reduction systems. Moreover, better thermodynamics and kinetics conditions for the reduction of scale can be reached. As a result, the reduction rate is increased.

  10. Continuous Strip Reduction Test Simulating Tribological Conditions in Ironing

    DEFF Research Database (Denmark)

    Üstünyagiz, Esmeray; Nielsen, Chris Valentin; Christiansen, Peter

    2017-01-01

    materials, surface roughnesses, normal pressure, sliding length, sliding speed, interface temperature and lubrication. This paper proposes a new Strip Reduction Test (SRT) for industrial ironing processes that is capable of replicating the highly severe tribological conditions that are experienced during...

  11. Arsenic(V) reduction in relation to Iron(III) transformation and molecular characterization of the structural and functional microbial community in sediments of a basin-fill aquifer in Northern Utah.

    Science.gov (United States)

    Mirza, Babur S; Muruganandam, Subathra; Meng, Xianyu; Sorensen, Darwin L; Dupont, R Ryan; McLean, Joan E

    2014-05-01

    Basin-fill aquifers of the Southwestern United States are associated with elevated concentrations of arsenic (As) in groundwater. Many private domestic wells in the Cache Valley Basin, UT, have As concentrations in excess of the U.S. EPA drinking water limit. Thirteen sediment cores were collected from the center of the valley at the depth of the shallow groundwater and were sectioned into layers based on redoxmorphic features. Three of the layers, two from redox transition zones and one from a depletion zone, were used to establish microcosms. Microcosms were treated with groundwater (GW) or groundwater plus glucose (GW+G) to investigate the extent of As reduction in relation to iron (Fe) transformation and characterize the microbial community structure and function by sequencing 16S rRNA and arsenate dissimilatory reductase (arrA) genes. Under the carbon-limited conditions of the GW treatment, As reduction was independent of Fe reduction, despite the abundance of sequences related to Geobacter and Shewanella, genera that include a variety of dissimilatory iron-reducing bacteria. The addition of glucose, an electron donor and carbon source, caused substantial shifts toward domination of the bacterial community by Clostridium-related organisms, and As reduction was correlated with Fe reduction for the sediments from the redox transition zone. The arrA gene sequencing from microcosms at day 54 of incubation showed the presence of 14 unique phylotypes, none of which were related to any previously described arrA gene sequence, suggesting a unique community of dissimilatory arsenate-respiring bacteria in the Cache Valley Basin.

  12. Dolochar as a reductant in the reduction roasting of iron ore slimes

    Science.gov (United States)

    Rath, Swagat S.; Rao, Danda Srinivas

    2017-12-01

    The present investigation examines the viability of dolochar, a sponge iron industry waste material, as a reductant in the reduction roasting of iron ore slimes, which are another waste generated by iron ore beneficiation plants. Under statistically determined optimum conditions, which include a temperature of 900°C, a reductant-to-feed mass ratio of 0.35, and a reduction time of 30-45 min, the roasted mass, after being subjected to low-intensity magnetic separation, yielded an iron ore concentrate of approximately 64wt% Fe at a mass recovery of approximately 71% from the feed iron ore slime assaying 56.2wt% Fe. X-ray diffraction analyses indicated that the magnetic products contain magnetite and hematite as the major phases, whereas the nonmagnetic fractions contain quartz and hematite.

  13. [Influence of Dissimilatory Iron Reduction on the Speciation and Bioavailability of Heavy Metals in Soil].

    Science.gov (United States)

    Si, You-bin; Wang, Juan

    2015-09-01

    Fe(III) dissimilatory reduction by microbes is an important process of producing energy in the oxidation of organic compounds under anaerobic condition with Fe(III) as the terminal electron acceptor and Fe(II) as the reduction product. This process is of great significance in element biogeochemical cycle. Iron respiration has been described as one of the most ancient forms of microbial metabolism on the earth, which is bound up with material cycle in water, soil and sediments. Dissimilatory iron reduction plays important roles in heavy metal form transformation and the remediation of heavy metal and radionuclide contaminated soils. In this paper, we summarized the research progress of iron reduction in the natural environment, and discussed the influence and the mechanism of dissimilatory iron reduction on the speciation and bioavailability of heavy metals in soil. The effects of dissimilatory iron reduction on the speciation of heavy metals may be attributed to oxidation and reduction, methytation and immobilization of heavy metals in relation to their bioavailability in soils. The mechanisms of Fe(III) dissimilatory reduction on heavy metal form transformation contain biological and chemical interactions, but the mode of interaction remains to be further investigated.

  14. Reductive precipitation of neptunium on iron surfaces under anaerobic conditions

    Science.gov (United States)

    Yang, H.; Cui, D.; Grolimund, D.; Rondinella, V. V.; Brütsch, R.; Amme, M.; Kutahyali, C.; Wiss, A. T.; Puranen, A.; Spahiu, K.

    2017-12-01

    Reductive precipitation of the radiotoxic nuclide 237Np from nuclear waste on the surface of iron canister material at simulated deep repository conditions was investigated. Pristine polished as well as pre-corroded iron specimens were interacted in a deoxygenated solution containing 10-100 μM Np(V), with 10 mM NaCl and 2 mM NaHCO3 as background electrolytes. The reactivity of each of the two different systems was investigated by analyzing the temporal evolution of the Np concentration in the reservoir. It was observed that pre-oxidized iron specimen with a 40 μm Fe3O4 corrosion layer are considerably more reactive regarding the reduction and immobilization of aqueous Np(V) as compared to pristine polished Fe(0) surfaces. 237Np immobilized by the reactive iron surfaces was characterized by scanning electron microscopy as well as synchrotron-based micro-X-ray fluorescence and X-ray absorption spectroscopy. At the end of experiments, a 5-8 μm thick Np-rich layer was observed to be formed ontop of the Fe3O4 corrosion layer on the iron specimen. The findings from this work are significant in the context of performance assessments of deep geologic repositories using iron as high level radioactive waste (HLW) canister material and are of relevance regarding removing pollutants from contaminated soil or groundwater aquifer systems.

  15. Mercury methylation coupled to iron reduction by dissimilatory iron-reducing bacteria.

    Science.gov (United States)

    Si, Youbin; Zou, Yan; Liu, Xiaohong; Si, Xiongyuan; Mao, Jingdong

    2015-03-01

    Iron reduction and mercury methylation by dissimilatory iron-reducing bacteria (DIRB), Geobacter sulfurreducens and Shewanella oneidensis, were studied, and the relationship of mercury methylation coupled to iron reduction was determined. The ability of both bacteria for reducing iron was tested, and Fe(III) reduction occurred with the highest rate when ferric oxyhydroxide was used as a terminal electron acceptor. G. sulfurreducens had proven to mediate the production of methylmercury (MeHg), and a notable increase of MeHg following the addition of inorganic Hg was observed. When the initial concentration of HgCl2 was 500nM, about 177.03nM of MeHg was determined at 8d after G. sulfurreducens inoculation. S. oneidensis was tested negligible for Hg methylation and only 12.06nM of MeHg was determined. Iron reduction could potentially influence Hg methylation rates. The increase in MeHg was consistent with high rate of iron reduction, indicating that Fe(III) reduction stimulated the formation of MeHg. Furthermore, the net MeHg concentration increased at low Fe(III) additions from 1.78 to 3.57mM, and then decreased when the added Fe(III) was high from 7.14 to 17.85mM. The mercury methylation rate was suppressed with high Fe(III) additions, which might have been attributable to mercury complexation and low availability. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Effect of phosphorus addition on the reductive transformation of pentachlorophenol (PCP) and iron reduction with microorganism involvement.

    Science.gov (United States)

    Wang, Yongkui; Liu, Xianli; Huang, Jiexun; Xiao, Wensheng; Zhang, Jiaquan; Yin, Chunqin

    2017-10-01

    The transformation of phosphorus added to the soil environment has been proven to be influenced by the Fe biochemical process, which thereby may affect the transformation of organic chlorinated contaminants. However, the amount of related literatures regarding this topic is limited. This study aimed to determine the effects of phosphorus addition on pentachlorophenol (PCP) anaerobic transformation, iron reduction, and paddy soil microbial community structure. Results showed that the transformation of phosphorus, iron, and PCP were closely related to the microorganisms. Moreover, phosphorus addition significantly influenced PCP transformation and iron reduction, which promoted and inhibited these processes at low and high concentrations, respectively. Both the maximum reaction rate of PCP transformation and the maximum Fe(II) amount produced were obtained at 1 mmol/L phosphorus concentration. Among the various phosphorus species, dissolved P and NaOH-P considerably changed, whereas only slight changes were observed for the remaining phosphorus species. Microbial community structure analysis demonstrated that adding low concentration of phosphorus promoted the growth of Clostridium bowmanii, Clostridium hungatei, and Clostridium intestinale and Pseudomonas veronii. By contrast, high-concentration phosphorus inhibited growth of these microorganisms, similar to the curves of PCP transformation and iron reduction. These observations indicated that Clostridium and P. veronii, especially Clostridium, played a vital role in the transformation of related substances in the system. All these findings may serve as a reference for the complicated reactions among the multiple components of soils.

  17. Isolation of microorganisms involved in reduction of crystalline iron(III) oxides in natural environments.

    Science.gov (United States)

    Hori, Tomoyuki; Aoyagi, Tomo; Itoh, Hideomi; Narihiro, Takashi; Oikawa, Azusa; Suzuki, Kiyofumi; Ogata, Atsushi; Friedrich, Michael W; Conrad, Ralf; Kamagata, Yoichi

    2015-01-01

    Reduction of crystalline Fe(III) oxides is one of the most important electron sinks for organic compound oxidation in natural environments. Yet the limited number of isolates makes it difficult to understand the physiology and ecological impact of the microorganisms involved. Here, two-stage cultivation was implemented to selectively enrich and isolate crystalline iron(III) oxide reducing microorganisms in soils and sediments. Firstly, iron reducers were enriched and other untargeted eutrophs were depleted by 2-years successive culture on a crystalline ferric iron oxide (i.e., goethite, lepidocrocite, hematite, or magnetite) as electron acceptor. Fifty-eight out of 136 incubation conditions allowed the continued existence of microorganisms as confirmed by PCR amplification. High-throughput Illumina sequencing and clone library analysis based on 16S rRNA genes revealed that the enrichment cultures on each of the ferric iron oxides contained bacteria belonging to the Deltaproteobacteria (mainly Geobacteraceae), followed by Firmicutes and Chloroflexi, which also comprised most of the operational taxonomic units (OTUs) identified. Venn diagrams indicated that the core OTUs enriched with all of the iron oxides were dominant in the Geobacteraceae while each type of iron oxides supplemented selectively enriched specific OTUs in the other phylogenetic groups. Secondly, 38 enrichment cultures including novel microorganisms were transferred to soluble-iron(III) containing media in order to stimulate the proliferation of the enriched iron reducers. Through extinction dilution-culture and single colony isolation, six strains within the Deltaproteobacteria were finally obtained; five strains belonged to the genus Geobacter and one strain to Pelobacter. The 16S rRNA genes of these isolates were 94.8-98.1% identical in sequence to cultured relatives. All the isolates were able to grow on acetate and ferric iron but their physiological characteristics differed considerably in

  18. Volatile fatty acids as substrates for iron and sulfate reduction in Arctic marine sediments, Svalbard

    Science.gov (United States)

    Finke, N.; Vandieken, V.; Jorgensen, B. B.

    2006-12-01

    Anaerobic degradation of complex organic material in aquatic systems is a multi-step process. The metabolic products of fermentative bacteria serve as electron donors for the terminal oxidizing bacteria. In marine sediments, iron reduction and sulfate reduction are generally the most important terminal oxidation processes in the upper anoxic zone [1]. Microorganisms that reduce iron and sulfate may use a broad range of electron donors, yet the list of potential substrates provides little information about the substrates used in situ by these organisms. Investigations on the electron donors for sulfate reducers in marine sediments have shown that volatile fatty acids (VFA), and in particular acetate, together with hydrogen are the major substrates (e.g. [2-4]). Similar investigations for iron reduction or simultaneous iron and sulfate reduction are lacking for marine sediments. Furthermore, most of these studies were made in temperate sediments and little is known about the substrates for sulfate reducers in permanently cold sediments, which account for >90% of the ocean floor [5]. We investigated the relative contributions of iron reduction and sulfate reduction to the terminal oxidation of organic carbon and the importance of acetate, lactate, propionate, and isobutyrate as electron donors for iron and sulfate reduction in permanently cold, Arctic sediments from Svalbard. In the surface layer (0-2 cm) sulfate reduction accounted for 2/3 of the organic carbon oxidation (determined as DIC production), the remaining 1/3 were attributed to iron reduction. In the 5-9 cm layer sulfate reduction was the sole important terminal oxidation step. The contribution of acetate to terminal oxidation was determined by radiotracer incubation as well as from the accumulation after the inhibition of sulfate reduction by selenate. The rates determined with the two methods varied by less than 20%. Acetate turnover, determined with the tracer incubations, accounted for 10 and 40% of

  19. Ferric Iron Reduction by Bacteria Associated with the Roots of Freshwater and Marine Macrophytes†

    Science.gov (United States)

    King, G. M.; Garey, Meredith A.

    1999-01-01

    In vitro assays of washed, excised roots revealed maximum potential ferric iron reduction rates of >100 μmol g (dry weight)−1 day−1 for three freshwater macrophytes and rates between 15 and 83 μmol (dry weight)−1 day−1 for two marine species. The rates varied with root morphology but not consistently (fine root activity exceeded smooth root activity in some but not all cases). Sodium molybdate added at final concentrations of 0.2 to 20 mM did not inhibit iron reduction by roots of marine macrophytes (Spartina alterniflora and Zostera marina). Roots of a freshwater macrophyte, Sparganium eurycarpum, that were incubated with an analog of humic acid precursors, anthroquinone disulfate (AQDS), reduced freshly precipitated iron oxyhydroxide contained in dialysis bags that excluded solutes with molecular weights of >1,000; no reduction occurred in the absence of AQDS. Bacterial enrichment cultures and isolates from freshwater and marine roots used a variety of carbon and energy sources (e.g., acetate, ethanol, succinate, toluene, and yeast extract) and ferric oxyhydroxide, ferric citrate, uranate, and AQDS as terminal electron acceptors. The temperature optima for a freshwater isolate and a marine isolate were equivalent (approximately 32°C). However, iron reduction by the freshwater isolate decreased with increasing salinity, while reduction by the marine isolate displayed a relatively broad optimum salinity between 20 and 35 ppt. Our results suggest that by participating in an active iron cycle and perhaps by reducing humic acids, iron reducers in the rhizoplane of aquatic macrophytes limit organic availability to other heterotrophs (including methanogens) in the rhizosphere and bulk sediments. PMID:10508065

  20. Au/iron oxide catalysts: temperature programmed reduction and X-ray diffraction characterization

    International Nuclear Information System (INIS)

    Neri, G.; Visco, A.M.; Galvagno, S.; Donato, A.; Panzalorto, M.

    1999-01-01

    Gold on iron oxides catalysts have been characterized by temperature programmed reduction (TPR) and X-ray diffraction spectroscopy (XRD). The influence of preparation method, gold loading and pretreatment conditions on the reducibility of iron oxides have been investigated. On the impregnated Au/iron oxide catalysts as well as on the support alone the partial reduction of Fe(III) oxy(hydroxides) to Fe 3 O 4 starts in the 550 and 700 K temperature range. On the coprecipitated samples, the temperature of formation of Fe 3 O 4 is strongly dependent on the presence of gold. The reduction temperature is lowered as the gold loading is increased. The reduction of Fe 3 O 4 to FeO occurs at about 900 K and is not dependent on the presence of gold and the preparation method. It is suggested that the effect of gold on the reducibility of the iron oxides is related to an increase of the structural defects and/or of the surface hydroxyl groups. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  1. Kinetics of chromium (VI) reduction by ferrous iron

    International Nuclear Information System (INIS)

    Batchelor, B.; Schlautman, M.; Hwang, I.; Wang, R.

    1998-09-01

    Chromium is a primary inorganic contaminant of concern at the Pantex Plant. Chromium concentrations have been found to be two orders of magnitude higher than the drinking water standards, particularly in certain wells in the perched aquifer below Zone 12. In situ reduction of a mobile form of chromium, Cr(VI) to an immobile form, Cr(III), was examined as a viable option to active soil restoration. Successfully immobilizing chromium in the vadose zone as Cr(III) will reduce the amount of chromium that reaches the groundwater table. The results from the solution experiments indicated that chromium was rapidly and stoichiometrically reduced by Fe(II) in solution. Also, the slurry experiments showed that the aquifer solids removed Fe(II) from solution, but a portion of the iron removed remained available for reaction with Cr(VI), but at a slower rate. A model to predict different amounts of iron pseudo-components was developed, which allowed prediction of iron amounts required to reduce chromium under in situ conditions

  2. Iron and iron-related proteins in asbestosis.

    Science.gov (United States)

    ABSTRACT: We tested the postulate that iron homeostasis is altered among patients diagnosed to have asbestosis. Lung tissue from six individuals diagnosed to have had asbestosis at autopsy was stained for iron, ferritin, divalent metal transporter 1 (DMT1), and ferroportin 1 (FP...

  3. Studies of Actinides Reduction on Iron Surfaces by Means of Resonant Inelastic X-ray Scattering

    International Nuclear Information System (INIS)

    Kvashnina, K.O.; Butorin, S.M.; Shuh, D.K.; Ollila, K.; Soroka, I.; Guo, J.-H.; Werme, L.; Nordgren, J.

    2006-01-01

    The interaction of actinides with corroded iron surfaces was studied using resonant inelastic x-ray scattering (RIXS) spectroscopy at actinide 5d edges. RIXS profiles, corresponding to the f-f excitations are found to be very sensitive to the chemical states of actinides in different systems. Our results clearly indicate that U(VI) (as soluble uranyl ion) was reduced to U(IV) in the form of relatively insoluble uranium species, indicating that the iron presence significantly affects the mobility of actinides, creating reducing conditions. Also Np(V) and Pu (VI) in the ground water solution were getting reduced by the iron surface to Np(IV) and Pu (IV) respectively. Studying the reduction of actinides compounds will have an important process controlling the environmental behavior. Using RIXS we have shown that actinides, formed by radiolysis of water in the disposal canister, are likely to be reduced on the inset corrosion products and prevent release from the canister

  4. Experimental study and modelling of iron ore reduction by hydrogen

    International Nuclear Information System (INIS)

    Wagner, D.

    2008-01-01

    In an effort to find new ways to drastically reduce the CO 2 emissions from the steel industry (ULCOS project), the reduction of iron ore by pure hydrogen in a shaft furnace was investigated. The work consisted of literature, experimental, and modelling studies. The chemical reaction and its kinetics were analysed on the basis of thermogravimetric experiments and physicochemical characterizations of partially reduced samples. A specific kinetic model was designed, which simulates the successive reactions, the different steps of mass transport, and possible iron sintering, at the particle scale. Finally, a 2-dimensional numerical model of a shaft furnace was developed. It depicts the variation of the solid and gas temperatures and compositions throughout the reactor. One original feature of the model is using the law of additive characteristic times for calculating the reaction rates. This allowed us to handle both the particle and the reactor scale, while keeping reasonable calculation time. From the simulation results, the influence of the process parameters was assessed. Optimal operating conditions were concluded, which reveal the efficiency of the hydrogen process. (author)

  5. 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.

  6. Electrochemical depassivation of zero-valent iron for trichloroethene reduction

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Liang [Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences, Beijing 100083 (China); Jin, Song [Department of Civil and Architectural Engineering, University of Wyoming, Laramie, WY 82071 (United States); Advanced Environmental Technologies, LLC, Fort Collins, CO 80524 (United States); Fallgren, Paul H. [Department of Civil Engineering, University of Colorado Denver, Denver, CO 80217 (United States); Swoboda-Colberg, Norbert G. [Department of Geology and Geophysics, University of Wyoming, Laramie, WY 82071 (United States); Liu, Fei [Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences, Beijing 100083 (China); Colberg, Patricia J.S., E-mail: pczoo@uwyo.edu [Department of Civil and Architectural Engineering, University of Wyoming, Laramie, WY 82071 (United States)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Electrical current may depassivate ZVI and restore its capacity to reduce TCE. Black-Right-Pointing-Pointer Electrical current may defer or even prevent surface oxidation of ZVI. Black-Right-Pointing-Pointer Electrical current coupled with ZVI achieves greater TCE reduction than ZVI alone. - Abstract: Permeable reactive barriers (PRBs) composed of zero-valent iron (ZVI) are susceptible to passivation, resulting in substantially decreased rates of chlorinated solvent removal over time. In this study, the application of low electrical direct current (DC) to restore the reductive capacity of passivated ZVI was examined. Electrical current was applied to a laboratory column reactor filled with a mixture of pre-passivated ZVI and sand. Variable voltage settings (0-12 V) were applied through two stainless steel electrodes placed at the ends of the reactor. While only partial restoration of the reductive capacity of the passivated ZVI was observed, higher rates of trichloroethene (TCE) removal were always obtained when current was applied, and the rates of TCE removal were roughly proportional to the voltage level. Although differences were observed between the rates and extent of TCE removal within the column, it is noteworthy that TCE removal was not restricted to that region of the column where the electrons entered (i.e., at the cathode). While complete 'depassivation' of ZVI may be difficult to achieve in practice, the application of DC demonstrated observable restoration of reactivity of the passivated ZVI. This study provides evidence that this approach may significantly extend the life of a ZVI PRB.

  7. Electrochemical depassivation of zero-valent iron for trichloroethene reduction

    International Nuclear Information System (INIS)

    Chen, Liang; Jin, Song; Fallgren, Paul H.; Swoboda-Colberg, Norbert G.; Liu, Fei; Colberg, Patricia J.S.

    2012-01-01

    Highlights: ► Electrical current may depassivate ZVI and restore its capacity to reduce TCE. ► Electrical current may defer or even prevent surface oxidation of ZVI. ► Electrical current coupled with ZVI achieves greater TCE reduction than ZVI alone. - Abstract: Permeable reactive barriers (PRBs) composed of zero-valent iron (ZVI) are susceptible to passivation, resulting in substantially decreased rates of chlorinated solvent removal over time. In this study, the application of low electrical direct current (DC) to restore the reductive capacity of passivated ZVI was examined. Electrical current was applied to a laboratory column reactor filled with a mixture of pre-passivated ZVI and sand. Variable voltage settings (0–12 V) were applied through two stainless steel electrodes placed at the ends of the reactor. While only partial restoration of the reductive capacity of the passivated ZVI was observed, higher rates of trichloroethene (TCE) removal were always obtained when current was applied, and the rates of TCE removal were roughly proportional to the voltage level. Although differences were observed between the rates and extent of TCE removal within the column, it is noteworthy that TCE removal was not restricted to that region of the column where the electrons entered (i.e., at the cathode). While complete “depassivation” of ZVI may be difficult to achieve in practice, the application of DC demonstrated observable restoration of reactivity of the passivated ZVI. This study provides evidence that this approach may significantly extend the life of a ZVI PRB.

  8. Carbothermal Reduction of Iron Ore in Its Concentrate-Agricultural Waste Pellets

    Directory of Open Access Journals (Sweden)

    Zhulin Liu

    2018-01-01

    Full Text Available Carbon-containing pellets were prepared with the carbonized product of agricultural wastes and iron concentrate, and an experimental study on the direct reduction was carried out. The experimental results demonstrated that carbon-containing pellets could be rapidly reduced at 1200 to 1300°C in 15 minutes, and the proper holding time at high temperature was 15 to 20 min. The degree of reduction gradually increased with temperature rising, and the appropriate temperature of reducing pellets was 1200°C. The weight loss rate and reduction degree of pellets increased with the rise of carbon proportion, and the relatively reasonable mole ratio of carbon to oxygen was 0.9. A higher content of carbon and an appropriate content of volatile matters in biomass char were beneficial to the reduction of pellets. The carbon-containing pellets could be reduced at high speeds in the air, but there was some reoxidization phenomenon.

  9. Enhanced reductive dechlorination of DDT in an anaerobic system of dissimilatory iron-reducing bacteria and iron oxide

    International Nuclear Information System (INIS)

    Li, F.B.; Li, X.M.; Zhou, S.G.; Zhuang, L.; Cao, F.; Huang, D.Y.; Xu, W.; Liu, T.X.; Feng, C.H.

    2010-01-01

    The transformation of DDT was studied in an anaerobic system of dissimilatory iron-reducing bacteria (Shewanella decolorationis S12) and iron oxide (α-FeOOH). The results showed that S. decolorationis could reduce DDT into DDD, and DDT transformation rate was accelerated by the presence of α-FeOOH. DDD was observed as the primary transformation product, which was demonstrated to be transformed in the abiotic system of Fe 2+ + α-FeOOH and the system of DIRB + α-FeOOH. The intermediates of DDMS and DBP were detected after 9 months, likely suggesting that reductive dechlorination was the main dechlorination pathway of DDT in the iron-reducing system. The enhanced reductive dechlorination of DDT was mainly due to biogenic Fe(II) sorbed on the surface of α-FeOOH, which can serve as a mediator for the transformation of DDT. This study demonstrated the important role of DIRB and iron oxide on DDT and DDD transformation under anaerobic iron-reducing environments. - This is the first case reporting the reductive dechlorination of DDT in an anaerobic system of dissimilatory iron-reducing bacteria and iron oxide.

  10. Enhanced reductive dechlorination of DDT in an anaerobic system of dissimilatory iron-reducing bacteria and iron oxide

    Energy Technology Data Exchange (ETDEWEB)

    Li, F.B., E-mail: cefbli@soil.gd.c [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Li, X.M. [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Zhou, S.G.; Zhuang, L. [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Cao, F. [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Huang, D.Y.; Xu, W.; Liu, T.X. [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Feng, C.H. [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China)

    2010-05-15

    The transformation of DDT was studied in an anaerobic system of dissimilatory iron-reducing bacteria (Shewanella decolorationis S12) and iron oxide (alpha-FeOOH). The results showed that S. decolorationis could reduce DDT into DDD, and DDT transformation rate was accelerated by the presence of alpha-FeOOH. DDD was observed as the primary transformation product, which was demonstrated to be transformed in the abiotic system of Fe{sup 2+} + alpha-FeOOH and the system of DIRB + alpha-FeOOH. The intermediates of DDMS and DBP were detected after 9 months, likely suggesting that reductive dechlorination was the main dechlorination pathway of DDT in the iron-reducing system. The enhanced reductive dechlorination of DDT was mainly due to biogenic Fe(II) sorbed on the surface of alpha-FeOOH, which can serve as a mediator for the transformation of DDT. This study demonstrated the important role of DIRB and iron oxide on DDT and DDD transformation under anaerobic iron-reducing environments. - This is the first case reporting the reductive dechlorination of DDT in an anaerobic system of dissimilatory iron-reducing bacteria and iron oxide.

  11. Evidence for the Occurrence of Microbial Iron Reduction in Bulk Aerobic Unsaturated Sediments

    Science.gov (United States)

    Cooper, D. C.; Kukkadapu, R. K.; Smith, W. A.; Fox, D. T.; Plummer, M. A.; Hull, L. C.

    2003-12-01

    is dominated by microaerophiles and facultative anaerobes such as Aquaspirillum, Flexibacter, and Verrucomicrobium. Desulfobacterium and Pseudomonas are also present at relative proportions similar to that observed higher in the column. This trend continues to 6.5 fbs, the lowest depth sampled. M\\H{o}ssbauer spectroscopy indicates that pc/sp iron is being lost from the system, and the shift in microbial community structure towards facultative anaerobes capable of this metabolism (Pseudomonas, Clostridium) indicates that this shift may be engendered by either assimilatory or dissimilatory iron reducing microorganisms. Thus, anaerobic microbial processes in general, and microbial iron reduction in particular, may be important within nutrient-poor, unsaturated, bulk-aerobic vadose zone environments. Beyond this evidence for the occurrence of microbial iron reduction in an emulated vadose zone system, these data are difficult to reconcile. As is detailed in an associated poster presentation, the Clostridium results may indicate the growth of an obligate anaerobe in the upper, oxic portions of the column. As the oxygen content decreases with depth, the community then shifts away from obligate anaerobes (Clostridium) toward facultative anaerobes. This is an area of current inquiry, and questions/suggestions are encouraged.

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

    Science.gov (United States)

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

    2014-03-01

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

  13. The effect of diluting ruthenium by iron in RuxSey catalyst for oxygen reduction

    International Nuclear Information System (INIS)

    Delacote, Cyril; Lewera, Adam; Pisarek, Marcin; Kulesza, Pawel J.; Zelenay, Piotr; Alonso-Vante, Nicolas

    2010-01-01

    This study has focused on the synthesis of novel oxygen reduction reaction (ORR) chalcogenide catalysts, with Ru partially replaced by Fe in a cluster-type Ru x Se y . The catalysts were obtained by thermal decomposition of Ru 3 (CO) 12 and Fe(CO) 5 in the presence of Se. As indicated by the XPS data, the composition of catalyst nanoparticles depends on the solvent used (either p-xylene or dichlorobenzene). The presence of iron in synthesized catalysts has been confirmed by both EDAX and XPS. Voltammetric activation of the catalysts results in a partial removal of iron and unreacted selenium from the surface. The ORR performance of electrochemically pre-treated catalysts was evaluated using rotating disk and ring-disk electrodes in a sulfuric acid solution. No major change in the ORR mechanism relative to the Se/Ru catalyst has been observed with Fe-containing catalysts.

  14. Dominance of sulfur-fueled iron oxide reduction in low-sulfate freshwater sediments.

    Science.gov (United States)

    Hansel, Colleen M; Lentini, Chris J; Tang, Yuanzhi; Johnston, David T; Wankel, Scott D; Jardine, Philip M

    2015-11-01

    A central tenant in microbial biogeochemistry is that microbial metabolisms follow a predictable sequence of terminal electron acceptors based on the energetic yield for the reaction. It is thereby oftentimes assumed that microbial respiration of ferric iron outcompetes sulfate in all but high-sulfate systems, and thus sulfide has little influence on freshwater or terrestrial iron cycling. Observations of sulfate reduction in low-sulfate environments have been attributed to the presumed presence of highly crystalline iron oxides allowing sulfate reduction to be more energetically favored. Here we identified the iron-reducing processes under low-sulfate conditions within columns containing freshwater sediments amended with structurally diverse iron oxides and fermentation products that fuel anaerobic respiration. We show that despite low sulfate concentrations and regardless of iron oxide substrate (ferrihydrite, Al-ferrihydrite, goethite, hematite), sulfidization was a dominant pathway in iron reduction. This process was mediated by (re)cycling of sulfur upon reaction of sulfide and iron oxides to support continued sulfur-based respiration--a cryptic sulfur cycle involving generation and consumption of sulfur intermediates. Although canonical iron respiration was not observed in the sediments amended with the more crystalline iron oxides, iron respiration did become dominant in the presence of ferrihydrite once sulfate was consumed. Thus, despite more favorable energetics, ferrihydrite reduction did not precede sulfate reduction and instead an inverse redox zonation was observed. These findings indicate that sulfur (re)cycling is a dominant force in iron cycling even in low-sulfate systems and in a manner difficult to predict using the classical thermodynamic ladder.

  15. N2 Reduction and Hydrogenation to Ammonia by a Molecular Iron-Potassium Complex

    Science.gov (United States)

    Rodriguez, Meghan M.; Bill, Eckhard; Brennessel, William W.; Holland, Patrick L.

    2011-01-01

    The most common catalyst in the Haber-Bosch process for the hydrogenation of dinitrogen (N2) to ammonia is an iron surface promoted with K+, but soluble iron complexes have neither reduced the N-N bond of N2 to nitride nor produced large amounts of NH3 from N2. We report a molecular iron complex that reacts with N2 and a potassium reductant to give a complex with two nitrides, which are bound to iron and potassium cations. The product has a Fe3N2 core, implying that three iron atoms cooperate to break the N-N triple bond through a six-electron reduction. The nitride complex reacts with acid and with H2 to give substantial yields of N2-derived ammonia. These reactions, though not yet catalytic, give structural and spectroscopic insight into N2 cleavage and N-H bond-forming reactions of iron. PMID:22076372

  16. N₂reduction and hydrogenation to ammonia by a molecular iron-potassium complex.

    Science.gov (United States)

    Rodriguez, Meghan M; Bill, Eckhard; Brennessel, William W; Holland, Patrick L

    2011-11-11

    The most common catalyst in the Haber-Bosch process for the hydrogenation of dinitrogen (N(2)) to ammonia (NH(3)) is an iron surface promoted with potassium cations (K(+)), but soluble iron complexes have neither reduced the N-N bond of N(2) to nitride (N(3-)) nor produced large amounts of NH(3) from N(2). We report a molecular iron complex that reacts with N(2) and a potassium reductant to give a complex with two nitrides, which are bound to iron and potassium cations. The product has a Fe(3)N(2) core, implying that three iron atoms cooperate to break the N-N triple bond through a six-electron reduction. The nitride complex reacts with acid and with H(2) to give substantial yields of N(2)-derived ammonia. These reactions, although not yet catalytic, give structural and spectroscopic insight into N(2) cleavage and N-H bond-forming reactions of iron.

  17. Microbial dissimilatory iron(III) reduction: Studies on the mechanism and on processes of environmental relevance

    OpenAIRE

    Jahn, Michael

    2005-01-01

    Many microbes are able to respire aerobically oxygen or anaerobically other electron acceptors for example sulphate, nitrate, manganese(IV) or Fe(III). As iron minerals are widespread in nature, dissimilatory iron(III) reduction by different microorganisms is a very important process of anaerobic respiration. The general goal of this work was to improve the knowledge of processes, in which iron-reducing microbes are said to play an important role. For this purpose, in one part the focus wa...

  18. Riboflavin Biosynthesis Is Associated with Assimilatory Ferric Reduction and Iron Acquisition by Campylobacter Jejuni.

    NARCIS (Netherlands)

    Gaskin, D.J.H.; Holmes, K.; Mulholland, F.; Wells, J.

    2007-01-01

    One of the pathways involved in the acquisition of the essential metal iron by bacteria involves the reduction of insoluble Fe3+ to soluble Fe2+, followed by transport of Fe2+ to the cytoplasm. Flavins have been implicated as electron donors in this poorly understood process. Ferrous iron uptake is

  19. Natural clinoptilolite exchanged with iron: characterization and catalytic activity in nitrogen monoxide reduction

    Directory of Open Access Journals (Sweden)

    Daria Tito-Ferro

    2016-12-01

    Full Text Available The aim of this work was to characterize the natural clinoptilolite from Tasajeras deposit, Cuba, modified by hydrothermal ion-exchange with solutions of iron (II sulfate and iron (III nitrate in acid medium. Besides this, its catalytic activity to reduce nitrogen monoxide with carbon monoxide/propene in the presence of oxygen was evaluated. The characterization was performed by Mössbauer and UV-Vis diffuse reflectance spectroscopies and adsorption measurements. The obtained results lead to conclude that in exchanged samples, incorporated divalent and trivalent irons are found in octahedral coordination. Both irons should be mainly in cationic extra-framework positions inside clinoptilolite channels as charge compensating cations, and also as iron oxy-hydroxides resulting from limited hydrolysis of these cations. The iron (III exchanged samples has a larger amount of iron oxy-hydroxides agglomerates. The iron (II exchanged samples have additionally iron (II sulfate adsorbed. The catalytic activity in the nitrogen monoxide reduction is higher in the exchanged zeolites than starting. Among all samples, those exchanged of iron (II has the higher catalytic activity. This lead to outline that, main catalytically active centers are associated with divalent iron.

  20. Associations between single nucleotide polymorphisms in iron-related genes and iron status in multiethnic populations.

    Directory of Open Access Journals (Sweden)

    Christine E McLaren

    Full Text Available The existence of multiple inherited disorders of iron metabolism suggests genetic contributions to iron deficiency. We previously performed a genome-wide association study of iron-related single nucleotide polymorphisms (SNPs using DNA from white men aged ≥ 25 y and women ≥ 50 y in the Hemochromatosis and Iron Overload Screening (HEIRS Study with serum ferritin (SF ≤ 12 µg/L (cases and controls (SF >100 µg/L in men, SF >50 µg/L in women. We report a follow-up study of white, African-American, Hispanic, and Asian HEIRS participants, analyzed for association between SNPs and eight iron-related outcomes. Three chromosomal regions showed association across multiple populations, including SNPs in the TF and TMPRSS6 genes, and on chromosome 18q21. A novel SNP rs1421312 in TMPRSS6 was associated with serum iron in whites (p = 3.7 × 10(-6 and replicated in African Americans (p = 0.0012.Twenty SNPs in the TF gene region were associated with total iron-binding capacity in whites (p<4.4 × 10(-5; six SNPs replicated in other ethnicities (p<0.01. SNP rs10904850 in the CUBN gene on 10p13 was associated with serum iron in African Americans (P = 1.0 × 10(-5. These results confirm known associations with iron measures and give unique evidence of their role in different ethnicities, suggesting origins in a common founder.

  1. Reduction of vibrational interference from the iron core on HBTXIA

    International Nuclear Information System (INIS)

    Wilcock, P.D.

    1981-01-01

    The HBTXIA machine is a toroidal reversed field pinch which utilises a 1 volt second iron core. This paper looks briefly at the sources of vibration from the iron core and describes the design of a novel support system that has been installed to minimise the transmission of vibration to plasma diagnostics and other equipment during the machine pulse. Vibration measurements on the completed installation when the core is driven to saturation are reported and compared with calculations for a ground mounted core. (author)

  2. Utilization potentiality of coal as a reductant for the production of sponge iron. [5 refs

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, H P

    1976-10-01

    With the ambitious plan of the Government of India to produce about 70 million tonnes of steel per annum towards the end of the century, the requirement of coal would be enormous. This calls for judicious planning and conservation of coal. Modern trend in steel plant practice is to use blast furnaces of capacity 10,000 to 12,000 t/day requiring superior quality coke of low ash content which will become scarce. Concerted efforts should be made to by-pass blast furnace technique by adopting direct reduction for the production of metallized iron ore, that is sponge iron, and using this as feed stock in electric furnaces. Experience has shown that the use of sponge iron as feed stock for electric arc furnaces instead of the scrap available from various fabrication and steel works results in better production of alloy steels. The use of non-coking coal as reductant for production of sponge iron will help conserve coking coal for bigger steel plants. In the solid state reduction process the technological design of the sponge iron plant has to be tailored to the type of feed stock to be used, particularly iron ore and coal. In India, non-coking coal is available at close proximity to the iron ore mines containing high grade iron ore. Planning for sponge iron, utilizing large reserves of non-coking coal as feed stock therefore has considerable potentiality. India has vast reserves of high grade iron ore and comparatively meager amount of coking coal. This calls for planning for sponge iron using non-coking coal as feed stock.

  3. Characterization of a tricationic trigonal bipyramidal iron(IV) cyanide complex, with a very high reduction potential, and its iron(II) and iron(III) congeners.

    Science.gov (United States)

    England, Jason; Farquhar, Erik R; Guo, Yisong; Cranswick, Matthew A; Ray, Kallol; Münck, Eckard; Que, Lawrence

    2011-04-04

    Currently, there are only a handful of synthetic S = 2 oxoiron(IV) complexes. These serve as models for the high-spin (S = 2) oxoiron(IV) species that have been postulated, and confirmed in several cases, as key intermediates in the catalytic cycles of a variety of nonheme oxygen activating enzymes. The trigonal bipyramidal complex [Fe(IV)(O)(TMG(3)tren)](2+) (1) was both the first S = 2 oxoiron(IV) model complex to be generated in high yield and the first to be crystallographically characterized. In this study, we demonstrate that the TMG(3)tren ligand is also capable of supporting a tricationic cyanoiron(IV) unit, [Fe(IV)(CN)(TMG(3)tren)](3+) (4). This complex was generated by electrolytic oxidation of the high-spin (S = 2) iron(II) complex [Fe(II)(CN)(TMG(3)tren)](+) (2), via the S = 5/2 complex [Fe(III)(CN)(TMG(3)tren)](2+) (3), the progress of which was conveniently monitored by using UV-vis spectroscopy to follow the growth of bathochromically shifting ligand-to-metal charge transfer (LMCT) bands. A combination of X-ray absorption spectroscopy (XAS), Mössbauer and NMR spectroscopies was used to establish that 4 has a S = 0 iron(IV) center. Consistent with its diamagnetic iron(IV) ground state, extended X-ray absorption fine structure (EXAFS) analysis of 4 indicated a significant contraction of the iron-donor atom bond lengths, relative to those of the crystallographically characterized complexes 2 and 3. Notably, 4 has an Fe(IV/III) reduction potential of ∼1.4 V vs Fc(+/o), the highest value yet observed for a monoiron complex. The relatively high stability of 4 (t(1/2) in CD(3)CN solution containing 0.1 M KPF(6) at 25 °C ≈ 15 min), as reflected by its high-yield accumulation via slow bulk electrolysis and amenability to (13)C NMR at -40 °C, highlights the ability of the sterically protecting, highly basic peralkylguanidyl donors of the TMG(3)tren ligand to support highly charged high-valent complexes.

  4. Reduction of iron-bearing lunar minerals for the production of oxygen

    Science.gov (United States)

    Massieon, Charles; Cutler, Andrew; Shadman, Farhang

    1992-01-01

    The kinetics and mechanism of the reduction of simulants of the iron-bearing lunar minerals olivine ((Fe,Mg)2SiO4), pyroxene ((Fe,Mg,Ca)SiO3), and ilmenite (FeTiO3) are investigated, extending previous work with ilmenite. Fayalite is reduced by H2 at 1070 K to 1480 K. A layer of mixed silica glass and iron forms around an unreacted core. Reaction kinetics are influenced by permeation of hydrogen through this layer and a reaction step involving dissociated hydrogen. Reaction mechanisms are independent of Mg content. Augite, hypersthene, and hedenbergite are reduced in H2 at the same temperatures. The products are iron metal and lower iron silicates mixed throughout the mineral. Activation energy rises with calcium content. Ilmenite and fayalite are reduced with carbon deposited on partially reduced minerals via the CO disproportionation reaction. Reduction with carbon is rapid, showing the carbothermal reduction of lunar minerals is possible.

  5. Application Of Bacterial Iron Reduction For The Removal Of Iron Impurities From Industrial Silica Sand And Kaolin

    Science.gov (United States)

    Zegeye, A.; Yahaya, S.; Fialips, C. I.; White, M.; Manning, D. A.; Gray, N.

    2008-12-01

    Biogeochemical evidence exists to support the potential importance of crystalline or amorphous Fe minerals as electron acceptor for Fe reducing bacteria in soils and subsurface sediments. This microbial metabolic activity can be exploited as alternative method in different industrial applications. For instance, the removal of ferric iron impurities from minerals for the glass and paper industries currently rely on physical and chemical treatments having substantial economical and environmental disadvantages. The ability to remove iron by other means, such as bacterial iron reduction, may reduce costs, allow lower grade material to be mined, and improve the efficiency of mineral processing. Kaolin clay and silica sand are used in a wide range of industrial applications, particularly in paper, ceramics and glass manufacturing. Depending on the geological conditions of deposition, they are often associated with iron (hydr)oxides that are either adsorbed to the mineral surfaces or admixed as separate iron bearing minerals. In this study, we have examined the Fe(III) removal efficiency from kaolin and silica sand by a series of iron- reducing bacteria from the Shewanella species (S. alga BrY, S. oneidensis MR-1, S. putrefaciens CN32 and S. putrefaciens ATCC 8071) in the presence of anthraquinone 2,6 disulfonate (AQDS). We have also investigated the effectiveness of a natural organic matter, extracted with the silica sand, as a substitute to AQDS for enhancing Fe(III) reduction kinetics. The microbial reduction of Fe(III) was achieved using batch cultures under non-growth conditions. The rate and the extent of Fe(III) reduction was monitored as a function of the initial Fe(III) content, Shewanella species and temperature. The bacterially- treated minerals were analyzed by transmission electron microscopy (TEM) and X-ray diffraction (XRD) to observe any textural and mineralogical transformation. The whiteness and ISO brightness of the kaolin was also measured by

  6. Mechanism of the reduction of hexavalent chromium by organo-montmorillonite supported iron nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Pingxiao, E-mail: pppxwu@scut.edu.cn [College of Environmental Science and Engineering, South China University of Technology, Guangzhou 510006 (China); Li, Shuzhen [School of Chemical and Environmental Engineering, Wuyi University, Jiangmen, Guangdong Province 529020 (China); Ju, Liting [College of Environmental Science and Engineering, South China University of Technology, Guangzhou 510006 (China); Zhu, Nengwu [College of Environmental Science and Engineering, South China University of Technology, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); The Key Laboratory of Environmental Protection and Eco-Remediation of Guangdong Regular Higher Education Institutions (China); Wu, Jinhua; Li, Ping [College of Environmental Science and Engineering, South China University of Technology, Guangzhou 510006 (China); Dang, Zhi [College of Environmental Science and Engineering, South China University of Technology, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); The Key Laboratory of Environmental Protection and Eco-Remediation of Guangdong Regular Higher Education Institutions (China)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer Organo-montmorillonite supported iron nanoparticles were found to be more efficient in the removal of Cr(VI) than unsupported iron nanoparticles. Black-Right-Pointing-Pointer The iron nanoparticles were accommodated by the sectional structure of the clay minerals which were helpful to protect the nanoparticles from aggregating. Black-Right-Pointing-Pointer XPS and XANES provided some direct information about the reduction mechanisms. Black-Right-Pointing-Pointer The structure of the supported iron nanoparticles was stable in the reaction with Cr(VI). - Abstract: Iron nanoparticles exhibit greater reactivity than micro-sized Fe{sup 0}, and they impart advantages for groundwater remediation. In this paper, supported iron nanoparticles were synthesized to further enhance the speed and efficiency of remediation. Natural montmorillonite and organo-montmorillonite were chosen as supporting materials. The capacity of supported iron nanoparticles was evaluated, compared to unsupported iron nanoparticles, for the reduction of aqueous Cr(VI). The reduction of Cr(VI) was much greater with organo-montmorillonite supported iron nanoparticles and fitted the pseudo-second order equation better. With a dose at 0.47 g/L, a total removal capacity of 106 mg Cr/g Fe{sup 0} was obtained. Other factors that affect the efficiency of Cr(VI) removal, such as pH values, the initial Cr(VI) concentration and storage time of nanoparticles were investigated. X-ray photoelectron spectrometry (XPS) and X-ray absorption near edge structure (XANES) were used to figure out the mechanism of the removal of Cr(VI). XPS indicated that the Cr(VI) bound to the particle surface was completely reduced to Cr(III) under a range of conditions. XANES confirmed that the Cr(VI) reacted with iron nanoparticles was completely reduced to Cr(III).

  7. Mechanism of the reduction of hexavalent chromium by organo-montmorillonite supported iron nanoparticles

    International Nuclear Information System (INIS)

    Wu, Pingxiao; Li, Shuzhen; Ju, Liting; Zhu, Nengwu; Wu, Jinhua; Li, Ping; Dang, Zhi

    2012-01-01

    Highlights: ► Organo-montmorillonite supported iron nanoparticles were found to be more efficient in the removal of Cr(VI) than unsupported iron nanoparticles. ► The iron nanoparticles were accommodated by the sectional structure of the clay minerals which were helpful to protect the nanoparticles from aggregating. ► XPS and XANES provided some direct information about the reduction mechanisms. ► The structure of the supported iron nanoparticles was stable in the reaction with Cr(VI). - Abstract: Iron nanoparticles exhibit greater reactivity than micro-sized Fe 0 , and they impart advantages for groundwater remediation. In this paper, supported iron nanoparticles were synthesized to further enhance the speed and efficiency of remediation. Natural montmorillonite and organo-montmorillonite were chosen as supporting materials. The capacity of supported iron nanoparticles was evaluated, compared to unsupported iron nanoparticles, for the reduction of aqueous Cr(VI). The reduction of Cr(VI) was much greater with organo-montmorillonite supported iron nanoparticles and fitted the pseudo-second order equation better. With a dose at 0.47 g/L, a total removal capacity of 106 mg Cr/g Fe 0 was obtained. Other factors that affect the efficiency of Cr(VI) removal, such as pH values, the initial Cr(VI) concentration and storage time of nanoparticles were investigated. X-ray photoelectron spectrometry (XPS) and X-ray absorption near edge structure (XANES) were used to figure out the mechanism of the removal of Cr(VI). XPS indicated that the Cr(VI) bound to the particle surface was completely reduced to Cr(III) under a range of conditions. XANES confirmed that the Cr(VI) reacted with iron nanoparticles was completely reduced to Cr(III).

  8. ARSENIC ADSORPTION AND REDUCTION IN IRON-RICH SOILS NEARBY LANDFILLS IN NORTHWEST FLORIDA

    Directory of Open Access Journals (Sweden)

    Hongqin Xue

    2016-01-01

    Full Text Available In Florida, soils are mainly composed of Myakka, an acid soil characterized by a subsurface accumulation of humus and Al(III and Fe(III oxides. Downgradient of the landfills in Northwest Florida, elevated levels of iron and arsenic observations had been made in the groundwater from monitoring wells, which was attributed to the geomicrobial iron and arsenic reduction. There is thus an immediate research need for a better understanding of the reduction reactions that are responsible for the mobilization of iron and arsenic in the subsurface soil nearby landfills. Owing to the high Fe(III oxide content, As(V adsorption reactions with Fe(III oxide surfaces are particularly important, which may control As(V reduction. This research focused on the investigation of the biogeochemical processes of the subsurface soil nearby landfills of Northwest Florida. Arsenic and iron reduction was studied in batch reactors and quantified based on Monod-type microbial kinetic growth simulations. As(V adsorption in iron-rich Northwest Floridian soils was further investigated to explain the reduction observations. It was demonstrated in this research that solubilization of arsenic in the subsurface soil nearby landfills in Northwest Florida would likely occur under conditions favoring Fe(III dissimilatory reduction.

  9. Reduction Behaviors of Carbon Composite Iron Oxide Briquette Under Oxidation Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ki-Woo; Kim, Kang-Min; Kwon, Jae-Hong; Han, Jeong-Whan [Inha University, Incheon (Korea, Republic of); Son, Sang-Han [POSCO, Pohang (Korea, Republic of)

    2017-01-15

    The carbon composite iron oxide briquette (CCB) is considered a potential solution to the upcoming use of low grade iron resources in the ironmaking process. CCB is able to reduce raw material cost by enabling the use of low grade powdered iron ores and coal. Additionally, the fast reduction of iron oxides by direct contact with coal can be utilized. In this study, the reduction behaviors of CCB were investigated in the temperature range of 200-1200 ℃ under oxidizing atmosphere. Briquettes were prepared by mixing iron ore and coal in a weight ratio of 8:2. Then reduction experiments were carried out in a mixed gas atmosphere of N{sub 2}, O{sub 2}, and CO{sub 2}. Compressive strength tests and quantitative analysis were performed by taking samples at each target temperature. In addition, the reduction degree depending on the reaction time was evaluated by off-gas analysis during the reduction test. It was found that the compressive strength and the metallization degree of the reduced briquettes increased with increases in the reaction temperature and holding time. However, it tended to decrease when the re-oxidation phenomenon was caused by injected oxygen. The degree of reduction reached a maximum value in 26 minutes. Therefore, the re-oxidation phenomenon becomes dominant after 26 minutes.

  10. In Situ Spectroscopic Analysis of the Carbothermal Reduction Process of Iron Oxides during Microwave Irradiation

    Directory of Open Access Journals (Sweden)

    Jun Fukushima

    2018-01-01

    Full Text Available The effects of microwave plasma induction and reduction on the promotion of the carbothermal reduction of iron oxides (α-Fe2O3, γ-Fe2O3, and Fe3O4 are investigated using in situ emission spectroscopy measurements during 2.45 GHz microwave processing, and the plasma discharge (such as CN and N2 is measured during microwave E-field irradiation. It is shown that CN gas or excited CN molecules contribute to the iron oxide reduction reactions, as well as to the thermal reduction. On the other hand, no plasma is generated during microwave H-field irradiation, resulting in thermal reduction. Magnetite strongly interacts with the microwave H-field, and the reduction reaction is clearly promoted by microwave H-field irradiation, as well as thermal reduction reaction.

  11. Copper increases reductive dehalogenation of haloacetamides by zero-valent iron in drinking water: Reduction efficiency and integrated toxicity risk.

    Science.gov (United States)

    Chu, Wenhai; Li, Xin; Bond, Tom; Gao, Naiyun; Bin, Xu; Wang, Qiongfang; Ding, Shunke

    2016-12-15

    The haloacetamides (HAcAms), an emerging class of nitrogen-containing disinfection byproducts (N-DBPs), are highly cytotoxic and genotoxic, and typically occur in treated drinking waters at low μg/L concentrations. Since many drinking distribution and storage systems contain unlined cast iron and copper pipes, reactions of HAcAms with zero-valent iron (ZVI) and metallic copper (Cu) may play a role in determining their fate. Moreover, ZVI and/or Cu are potentially effective HAcAm treatment technologies in drinking water supply and storage systems. This study reports that ZVI alone reduces trichloroacetamide (TCAcAm) to sequentially form dichloroacetamide (DCAcAm) and then monochloroacetamide (MCAcAm), whereas Cu alone does not impact HAcAm concentrations. The addition of Cu to ZVI significantly improved the removal of HAcAms, relative to ZVI alone. TCAcAm and their reduction products (DCAcAm and MCAcAm) were all decreased to below detection limits at a molar ratio of ZVI/Cu of 1:1 after 24 h reaction (ZVI/TCAcAm = 0.18 M/5.30 μM). TCAcAm reduction increased with the decreasing pH from 8.0 to 5.0, but values from an integrated toxic risk assessment were minimised at pH 7.0, due to limited removal MCAcAm under weak acid conditions (pH = 5.0 and 6.0). Higher temperatures (40 °C) promoted the reductive dehalogenation of HAcAms. Bromine was preferentially removed over chlorine, thus brominated HAcAms were more easily reduced than chlorinated HAcAms by ZVI/Cu. Although tribromoacetamide was more easily reduced than TCAcAm during ZVI/Cu reduction, treatment of tribromoacetamide resulted in a higher integrated toxicity risk than TCAcAm, due to the formation of monobromoacetamide (MBAcAm). Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Energy Saving Melting and Revert Reduction Technology: Aging of Graphitic Cast Irons and Machinability

    Energy Technology Data Exchange (ETDEWEB)

    Richards, Von L. [Advanced Technology Inst., Virginia Beach, VA (United States)

    2012-09-19

    The objective of this task was to determine whether ductile iron and compacted graphite iron exhibit age strengthening to a statistically significant extent. Further, this effort identified the mechanism by which gray iron age strengthens and the mechanism by which age-strengthening improves the machinability of gray cast iron. These results were then used to determine whether age strengthening improves the machinability of ductile iron and compacted graphite iron alloys in order to develop a predictive model of alloy factor effects on age strengthening. The results of this work will lead to reduced section sizes, and corresponding weight and energy savings. Improved machinability will reduce scrap and enhance casting marketability. Technical Conclusions: Age strengthening was demonstrated to occur in gray iron ductile iron and compacted graphite iron. Machinability was demonstrated to be improved by age strengthening when free ferrite was present in the microstructure, but not in a fully pearlitic microstructure. Age strengthening only occurs when there is residual nitrogen in solid solution in the Ferrite, whether the ferrite is free ferrite or the ferrite lamellae within pearlite. Age strengthening can be accelerated by Mn at about 0.5% in excess of the Mn/S balance Estimated energy savings over ten years is 13.05 trillion BTU, based primarily on yield improvement and size reduction of castings for equivalent service. Also it is estimated that the heavy truck end use of lighter castings for equivalent service requirement will result in a diesel fuel energy savings of 131 trillion BTU over ten years.

  13. Solid-state Water-mediated Transport Reduction of Nanostructured Iron Oxides

    International Nuclear Information System (INIS)

    Smirnov, Vladimir M.; Povarov, Vladimir G.; Voronkov, Gennadii P.; Semenov, Valentin G.; Murin, Igor' V.; Gittsovich, Viktor N.; Sinel'nikov, Boris M.

    2001-01-01

    The Fe 2+ /Fe 3+ ratio in two-dimensional iron oxide nanosructures (nanolayers with a thickness of 0.3-1.5 nm on silica surface) may be precisely controlled using the transport reduction (TR) technique. The species ≡-O-Fe(OH) 2 and (≡Si-O-) 2 -FeOH forming the surface monolayer are not reduced at 400-600 deg. C because of their covalent bonding to the silica surface, as demonstrated by Moessbauer spectroscopy. Iron oxide microparticles (microstructures) obtained by the impregnation technique, being chemically unbound to silica, are subjected to reduction at T ≥ 500 deg. C with formation of metallic iron in the form of α-Fe. Transport reduction of supported nanostructures (consisting of 1 or 4 monolayers) at T ≥ 600 deg. C produces bulk iron(II) silicate and metallic iron phases. The structural-chemical transformations occurring in transport reduction of supported iron oxide nanolayers are proved to be governed by specific phase processes in the nanostructures themselves

  14. Comparison of the Efficiencies of Zero-Valent Iron Nanoparticles and Stabilized Iron Nanoparticles for Nitrate Reduction from Polluted Waters

    Directory of Open Access Journals (Sweden)

    Fatemeh Nooralivand

    2015-12-01

    Full Text Available The present study was conducted to evaluate the feasibility of zero-valent iron nanoparticles (ZVIN for the removal of nitrate from aqueous solutions. For this purpose, bare zero-valent iron nanoparticles (bare-ZVIN and CMC-ZVIN were synthesized using the borohydride reduction method and their morphological characteristics were examined via scanning electron microscopy (SEM, X-ray diffraction (XRD, and Fourier Transmission Infrared Spectroscopy (FTIR. The effects of pH of the aqueous solution, initial nitrate concentration, ZVIN concentration, and contact time on nitrate reduction were investigated as operational parameters and the kinetics of nitrate reduction was studied in batch experiments. The results showed that 93.65% of nitrate was removed by stabilized nanoparticles at pH=6 while non-stabilized nanoparticles at pH=2 were able to remove 85.55% of the nitrate.Furthermore, nitrate reduction was enhanced by increasing ZVIN concentration and contact time while it was decreased as a result of increasing initial nitrate concentration. The major product of nitrate reduction at an acidic pH was found to be ammonium; at an alkaline pH, however, nitrate was converted to nitrogen and nitrite production dropped to less than 2%. Kinetic analysis demonstrated that denitrification of nitrate by the nanoparticles fitted well with first-order and second-order reaction models. The results also demonstrated that the stabilized ZVI nanoparticles were more effective than bare-ZVIN for nitrate reduction in aqueous solutions.

  15. Electrochemical reduction of nitroaromatic compounds by single sheet iron oxide coated electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Li-Zhi, E-mail: lizhi@plen.ku.dk [Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK–1871 Frederiksberg C (Denmark); Hansen, Hans Christian B. [Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK–1871 Frederiksberg C (Denmark); Bjerrum, Morten Jannik [Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK–2100 København Ø (Denmark)

    2016-04-05

    Highlights: • Composite layers of single sheet iron oxides were coated on indium tin oxide electrodes. • Single sheet iron oxide is an electro-catalyst for reduction of nitroaromatic compounds in aqueous solution. • The reduction is well explained by a diffusion layer model. • The charge properties of the nitrophenols have an important influence on reduction. • Low-cost iron oxide based materials are promising electro-catalyst for water treatment. - Abstract: Nitroaromatic compounds are substantial hazard to the environment and to the supply of clean drinking water. We report here the successful reduction of nitroaromatic compounds by use of iron oxide coated electrodes, and demonstrate that single sheet iron oxides formed from layered iron(II)-iron(III) hydroxides have unusual electrocatalytic reactivity. Electrodes were produced by coating of single sheet iron oxides on indium tin oxide electrodes. A reduction current density of 10 to 30 μA cm{sup −2} was observed in stirred aqueous solution at pH 7 with concentrations of 25 to 400 μM of the nitroaromatic compound at a potential of −0.7 V vs. SHE. Fast mass transfer favors the initial reduction of the nitroaromatic compound which is well explained by a diffusion layer model. Reduction was found to comprise two consecutive reactions: a fast four-electron first-order reduction of the nitro-group to the hydroxylamine-intermediate (rate constant = 0.28 h{sup −1}) followed by a slower two-electron zero-order reduction resulting in the final amino product (rate constant = 6.9 μM h{sup −1}). The zero-order of the latter reduction was attributed to saturation of the electrode surface with hydroxylamine-intermediates which have a more negative half-wave potential than the parent compound. For reduction of nitroaromatic compounds, the SSI electrode is found superior to metal electrodes due to low cost and high stability, and superior to carbon-based electrodes in terms of high coulombic efficiency and

  16. Assessing the potential of spectral induced polarization to detect in situ changes in iron reduction

    Science.gov (United States)

    Rosier, C. L.; Price, A.; Sharma, S.; Atekwana, E. A.

    2016-12-01

    The near surface geophysical technique Spectral Induced Polarization (SIP), provides promise as an effective method measuring in situ biofilm formation/development. Yet, potential mechanisms responsible for observed shifts in SIP response due to biofilm are not clearly understood. In order to address possible mechanisms we assessed the influence of Shewanella oneidensis (MR1) cell density (colony forming units; CFU), biofilm production (Bradford assay) and iron reduction metabolism (colorimetric assay) on SIP response. Laboratory measurements were collected over three months on columns packed with either iron-coated or iron-free sands and amended with artificial ground water and acetate in order to stimulate biofilm production and microbial iron reduction. Additionally, scanning electron microscopy (SEM) was used to confirm the presence of S. oneidensis cells and biofilm. Our results suggest that during early/initial stage (75 days) of column incubation, SIP measurements revealed that phase and imaginary conductivity responses decreased as the concentration of reduced iron decreased below 2.0 mM. In contrast, we observed only a moderate increase in phase and imaginary conductivity ( 30%) within iron-free columns as a result of increases in S. oneidensis cells (CFU 1.5 x 1011) and biofilm production (7.0 mg ml-1). SEM analysis confirmed the presence of biofilm and cells within both iron-coated and iron-free columns. We hypothesize that the production of microbial metabolic byproducts is a potential mechanism explaining large phase shits observed in previous studies ( 50 mrads) rather than the conductivity of cells or biofilm. Our findings provide support for the following: i) ratio of cells to biofilm production only moderately influences both phase and imaginary conductivity response and ii) largest phase and imaginary conductivity response resulted from microbial metabolism (i.e. iron reduction) and potentially biofilm trapping of conductive materials (i

  17. Innocuous oil as an additive for reductive reactions involving zero valence iron

    International Nuclear Information System (INIS)

    Cary, J.W.; Cantrell, K.J.

    1994-11-01

    Reductive reactions involving zero valence iron appear to hold promise for in situ remediation of sites containing chlorinated hydrocarbon solvents and certain reducible metals and radionuclides. Treatment involves the injection of metallic iron and the creation of low levels of dissolved oxygen in the aqueous phase through oxidation of the metallic iron. The use of a biodegradable immiscible and innocuous organic liquid such as vegetable oil as an additive offers several intriguing possibilities. The oil phase creates a large oil-water interface that is immobile with respect to flow in the aqueous phase. This phase will act as a trap for chlorinated hydrocarbons and could potentially increase the reaction efficiency of reductive dehalogenation of chlorinated hydrocarbons by the metallic iron. When iron particles are suspended in the oil before injection they are preferentially held in the oil phase and tend to accumulate at the oil-water interface. Thus oil injection can serve as a mechanism for creating a stable porous curtain of metallic iron in the vadose to maintain a low oxygen environment which will minimize the consumption of the iron by molecular oxygen

  18. Significance of iron reduction for the therapy of chronic hepatitis C

    Directory of Open Access Journals (Sweden)

    Nožić Darko

    2005-01-01

    Full Text Available Background. It has been established that many patients with chronic hepatitis C have elevated serum iron, feritin levels and iron deposits in the liver. Therefore, the liver damage due to hepatitis C virus may be aggravated with iron overload. In many studies higher levels of iron in the blood and the liver were connected with the decreased response to interferon-alfa therapy for chronic viral hepatitis C. Recent introduction of pegylated interferons plus ribavirin has improved the therapeutic response, so it is now possible to cure more than 50% of the patients. Case report. Three patients with chronic hepatitis C and iron overload were presented. Iron reduction therapy using phlebotomy or eritrocytapheresis with plasmapheresis was done at different times in regard to specific antiviral therapy or as a sole therapy. Conclusion. It has been shown that iron reduction, sole or combined with antiviral therapy, led to the deacreased aminotransferase serum activity and might have slow down the evolution of chronic hepatitis C viral infection.

  19. Preparation of Metallic Iron Powder from Pyrite Cinder by Carbothermic Reduction and Magnetic Separation

    Directory of Open Access Journals (Sweden)

    Hongming Long

    2016-04-01

    Full Text Available The reduction and magnetic separation procedure of pyrite cinder in the presence of a borax additive was performed for the preparation of reduced powder. The effects of borax dosage, reduction temperature, reduction time and grinding fineness were investigated. The results show that when pyrite cinder briquettes with 5% borax were pre-oxidized at 1050 °C for 10 min, and reduced at 1050 °C for 80 min, with the grinding fineness (<0.44 mm passing 81%, the iron recovery was 91.71% and the iron grade of the magnetic concentrate was 92.98%. In addition, the microstructures of the products were analyzed by optical microscope, scanning electron microscope (SEM, and mineralography, and the products were also studied by the X-ray powder diffraction technique (XRD to investigate the mechanism; the results show that the borax additive was approved as a good additive to improve the separation of iron and gangue.

  20. Acetate, lactate, propionate, and isobutyrate as electron donors for iron and sulfate reduction in Arctic marine sediments, Svalbard

    DEFF Research Database (Denmark)

    Finke, Niko; Vandieken, Verona; Jørgensen, Bo Barker

    2007-01-01

    The contribution of volatile fatty acids (VFA) as e--donors for anaerobic terminal oxidation of organic carbon through iron and sulfate reduction was studied in Arctic fjord sediment. Dissolved inorganic carbon, Fe2+, VFA concentrations, and sulfate reduction were monitored in slurries from...... by alternative e--donors. The accumulation of VFA in the selenate-inhibited 0-2 cm slurry did not enhance iron reduction, indicating that iron reducers were not limited by VFA availability....

  1. In situ redox manipulation of subsurface sediments from Fort Lewis, Washington: Iron reduction and TCE dechlorination mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    JE Szecsody; JS Fruchter; DS Sklarew; JC Evans

    2000-03-21

    Pacific Northwest National Laboratory (PNNL) conducted a bench-scale study to determine how effective chemically treated Ft. Lewis sediments can degrade trichloroethylene (TCE). The objectives of this experimental study were to quantify: (1) sediment reduction and oxidation reactions, (2) TCE degradation reactions, and (3) other significant geochemical changes that occurred. Sediment reduction and oxidation were investigated to determine the mass of reducible iron in the Ft. Lewis sediments and the rate of this reduction and subsequent oxidation at different temperatures. The temperature dependence was needed to be able to predict field-scale reduction in the relatively cold ({approximately}11 C) Ft. Lewis aquifer. Results of these experiments were used in conjunction with other geochemical and hydraulic characterization to design the field-scale injection experiment and predict barrier longevity. For example, the sediment reduction rate controls the amount of time required for the dithionite solution to fully react with sediments. Sediment oxidation experiments were additionally conducted to determine the oxidation rate and provide a separate measure of the mass of reduced iron. Laboratory experiments that were used to meet these objectives included: (1) sediment reduction in batch (static) systems, (2) sediment reduction in 1-D columns, and (3) sediment oxidation in 1-D columns. Multiple reaction modeling was conducted to quantify the reactant masses and reaction rates.

  2. Recovery of iron from cyanide tailings with reduction roasting–water leaching followed by magnetic separation

    International Nuclear Information System (INIS)

    Zhang, Yali; Li, Huaimei; Yu, Xianjin

    2012-01-01

    Highlights: ► Using reduction roasting–water leaching–magnetic separation method, the recovery of iron from cyanide tailings was optimized. ► The recovery of iron was highly depended on the water-leaching process after reduction roasting. ► The results suggest that the method can be effectively used for iron recovery, and the grade of magnetic concentrate and recovery rate can reach 59.11% and 75.12%, respectively. - Abstract: Cyanide tailing is a kind of solid waste produced in the process of gold extraction from gold ore. In this paper, recovery of iron from cyanide tailings was studied with reduction roasting–water leaching process followed by magnetic separation. After analysis of chemical composition and crystalline phase, the effects of different parameters on recovery of iron were chiefly introduced. Systematic studies indicate that the high recovery rate and grade of magnetic concentrate of iron can be achieved under the following conditions: weight ratios of cyanide tailings/activated carbon/sodium carbonate/sodium sulfate, 100:10:3:10; temperature, 50 °C; time, 60 min at the reduction roasting stage; the liquid to solid ratio is 15:1 (ml/g), leaching at 60 °C for 5 min and stirring speed at 20 r/min at water-leaching; exciting current is 2 A at magnetic separation. The iron grade of magnetic concentrate was 59.11% and the recovery ratio was 75.12%. The mineralography of cyanide tailings, roasted product, water-leached sample, magnetic concentrate and magnetic tailings were studied by X-ray powder diffraction (XRD) technique. The microstructures of above products except magnetic tailings were also analyzed by scanning electron microscope (SEM) and energy disperse spectroscopy (EDS) to help understand the mechanism.

  3. Surface carbon influences on the reductive transformation of TCE in the presence of granular iron.

    Science.gov (United States)

    Firdous, R; Devlin, J F

    2018-04-05

    To gain insight into the processes of transformations in zero-valent iron systems, electrolytic iron (EI) has been used as a surrogate for the commercial products actually used in barriers. This substitution facilitates mechanistic studies, but may not be fully representative of all the relevant processes at work in groundwater remediation. To address this concern, the kinetic iron model (KIM) was used to investigate sorption and reactivity differences between EI and Connelly brand GI, using TCE as a probe compound. It was observed that retardation factors (R app ) for GI varied non-linearly with influent concentrations to the columns (C o ), and declined significantly as GI aged. In contrast, R app values for EI were small and insensitive to C o , and changed minimally with iron aging. Moreover, although declines in the rate constants (k) and increases in the sorption coefficients were observed for both iron types, they were most pronounced in the case of EI. SEM scans of the EI surface before and after aging (90 days) established the appearance of carbon on the older surface. This work provides evidence that iron with a higher surface carbon content outperforms pure iron, suggesting that the carbon is actively involved in promoting TCE reduction. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Biostimulation of Iron Reduction and Uranium Immobilization: Microbial and Mineralogical Controls

    International Nuclear Information System (INIS)

    Joel E. Kostka; Lainie Petrie; Nadia North; David L. Balkwill; Joseph W. Stucki; Lee Kerkhof

    2004-01-01

    The overall objective of our project is to understand the microbial and geochemical mechanisms controlling the reduction and immobilization of U(VI) during biostimulation in subsurface sediments of the Field Research Center (FRC) which are cocontaminated with uranium and nitrate. The focus will be on activity of microbial populations (metal- and nitrate-reducing bacteria) and iron minerals which are likely to make strong contributions to the fate of uranium during in situ bioremediation. The project will: (1) quantify the relationships between active members of the microbial communities, iron mineralogy, and nitrogen transformations in the field and in laboratory incubations under a variety of biostimulation conditions, (2) purify and physiologically characterize new model metal-reducing bacteria isolated from moderately acidophilic FRC subsurface sediments, and (3) elucidate the biotic and abiotic mechanisms by which FRC aluminosilicate clay minerals are reduced and dissolved under environmental conditions resembling those during biostimulation. Active microbial communities will be assessed using quantitative molecular techniques along with geochemical measurements to determine the different terminal-electron-accepting pathways. Iron minerals will be characterized using a suite of physical, spectroscopic, and wet chemical methods. Monitoring the activity and composition of the denitrifier community in parallel with denitrification intermediates during nitrate removal will provide a better understanding of the indirect effects of nitrate reduction on uranium speciation. Through quantification of the activity of specific microbial populations and an in-depth characterization of Fe minerals likely to catalyze U sorption/precipitation, we will provide important inputs for reaction-based biogeochemical models which will provide the basis for development of in situ U bioremediation strategies. In collaboration with Jack Istok and Lee Krumholz, we have begun to study the

  5. Screening the performance of lubricants for ironing of stainless steel with a strip reduction test

    DEFF Research Database (Denmark)

    Andreasen, Jan Lasson; Bay, Niels; Andersen, Mette Merete

    1997-01-01

    A laboratory strip reduction test simulating the tribological conditions of an ironing process is proposed. The test is capable of simulating varying process conditions such as reduction, drawing speed, tool temperature and sliding length. The test makes it possible to quantify the onset of break...... of breakdown of the lubricant film and subsequent galling. Experimental investigations of stainless steel show the influence of varying process conditions and the performance of different lubricants.......A laboratory strip reduction test simulating the tribological conditions of an ironing process is proposed. The test is capable of simulating varying process conditions such as reduction, drawing speed, tool temperature and sliding length. The test makes it possible to quantify the onset...

  6. Controlled electropolymerisation of a carbazole-functionalised iron porphyrin electrocatalyst for CO2 reduction

    DEFF Research Database (Denmark)

    Hu, Xinming; Salmi, Zakaria; Lillethorup, Mie

    2016-01-01

    Using a one-step electropolymerisation procedure, CO2 absorbing microporous carbazole-functionalised films of iron porphyrins are prepared in a controlled manner. The electrocatalytic reduction of CO2 for these films is investigated to elucidate their efficiency and the origin of their ultimate...

  7. Potentiometric assessment of iron release during ferritin reduction by exogenous agents.

    Science.gov (United States)

    Vladimirova, Lilia S; Kochev, Valery K

    2010-09-01

    This work studied the possibilities for quantitative determination of iron mobilization in connection with ferritin reduction by ascorbic acid (vitamin C) and sodium dithionite in vitro. The iron storage protein was incubated with an excess of reductant in aerobic conditions in the absence of complexing agents in the medium. The release of Fe(2+) was let to go to completion, and the overall content of Fe(2+) in the solution was evaluated with the aid of potentiometric titration using Ce(4+) as an oxidizing titrant. Results suggest a moderate iron efflux under the influence of the chosen reducing agents. Although such a reduction of the protein mineral core by dihydroxyfumarate contributes greatly to the iron mobilization, ferritin behavior with vitamin C and dithionite seems to be different. Although redox properties of dihydroxyfumarate are determined by hydroxyl groups similar to those of ascorbic acid, the two compounds differ significantly in structure, and this could be the basis for an explanation of the specificities in their interaction with ferritin. As revealed by the study, potentiometric titration promises to be a reliable tool for evaluation of the amount of Fe(2+) present in the solution as a result of the reduction of the ferritin's mineral core. 2010 Elsevier Inc. All rights reserved.

  8. Evidence for Microbial Iron Reduction in a Landfill Leachate-Polluted Aquifer (Vejen, Denmark)

    DEFF Research Database (Denmark)

    Albrechtsen, Hans-Jørgen; Christensen, Thomas Højlund

    1994-01-01

    Aquifer sediment samples obtained from the anaerobic part of a landfill leachate plume in Vejen, Denmark, were suspended in groundwater or in an artificial medium and incubated. The strictly anaerobic suspensions were tested for reduction of ferric iron (Fe(III)) oxides, which was measured...

  9. Obligatory reduction of ferric chelates in iron uptake by soybeans.

    Science.gov (United States)

    Chaney, R L; Brown, J C; Tiffin, L O

    1972-08-01

    The contrasting Fe(2+) and Fe(3+) chelating properties of the synthetic chelators ethylenediaminedi (o-hydroxyphenylacetate) (EDDHA) and 4,7-di(4-phenylsulfonate)-1, 10-phenanthroline (bathophenanthrolinedisulfonate) (BPDS) were used to determine the valence form of Fe absorbed by soybean roots supplied with Fe(3+)-chelates. EDDHA binds Fe(3+) strongly, but Fe(2+) weakly; BPDS binds Fe(2+) strongly but Fe(3+) weakly. Addition of an excess of BPDS to nutrient solutions containing Fe(3+)-chelates inhibited soybean Fe uptake-translocation by 99+%; [Fe(II) (BPDS)(3)](4-) accumulated in the nutrient solution. The addition of EDDHA caused little or no inhibition. These results were observed with topped and intact soybeans. Thus, separation and absorption of Fe from Fe(3+)-chelates appear to require reduction of Fe(3+)-chelate to Fe(2+)-chelate at the root, with Fe(2+) being the principal form of Fe absorbed by soybean.

  10. Influence of dihydroxybenzenes on paracetamol and ciprofloxacin degradation and iron(III) reduction in Fenton processes.

    Science.gov (United States)

    Costa E Silva, Beatriz; de Lima Perini, João Angelo; Nogueira, Raquel F Pupo

    2017-03-01

    The degradation of paracetamol (PCT) and ciprofloxacin (CIP) was compared in relation to the generation of dihydroxylated products, Fe(III) reduction and reaction rate in the presence of dihydroxybenzene (DHB) compounds, or under irradiation with free iron (Fe 3+ ) or citrate complex (Fecit) in Fenton or photo-Fenton process. The formation of hydroquinone (HQ) was observed only during PCT degradation in the dark, which increased drastically the rate of PCT degradation, since HQ formed was able to reduce Fe 3+ and contributed to PCT degradation efficiency. When HQ was initially added, PCT and CIP degradation rate in the dark was much higher in comparison to the absence of HQ, due to the higher and faster formation of Fe 2+ at the beginning of reaction. In the absence of HQ, no CIP degradation was observed; however, when HQ was added after 30 min, the degradation rate increased drastically. Ten PCT hydroxylated intermediates were identified in the absence of HQ, which could contribute for Fe(III) reduction and consequently to the degradation in a similar way as HQ. During CIP degradation, only one product of hydroxyl radical attack on benzene ring and substitution of the fluorine atom was identified when HQ was added to the reaction medium.

  11. Ammonia from iron(II) reduction of nitrite and the Strecker synthesis: do iron(II) and cyanide interfere with each other?

    Science.gov (United States)

    Summers, D. P.; Lerner, N.

    1998-01-01

    The question of whether the production of ammonia, from the reduction of nitrite by iron(II), is compatible with its use in the Strecker synthesis of amino acids, or whether the iron and the cyanide needed for the Strecker synthesis interfere with each other, is addressed. Results show that the presence of iron(II) appears to have little, or no, effect on the Strecker synthesis. The presence of cyanide does interfere with reduction of nitrite, but the reduction proceeds at cyanide/iron ratios of less than 4:1. At ratios of about 2:1 and less there is only a small effect. The reduction of nitrite and the Strecker can be combined to proceed in each other's presence, to yield glycine from a mixture of nitrite, Fe+2, formaldehyde, and cyanide.

  12. Fundamentals of fast reduction of ultrafine iron ore at low temperature

    Institute of Scientific and Technical Information of China (English)

    Pei Zhao; Peimin Guo

    2008-01-01

    Fundamentals on the fast reduction of ultrafine iron ore at low temperature, including characterization of ultrafine ore, de- oxidation thermodynamics of stored-energy ultrafine ore, kinetics of iron ore deoxidation, and deoxidation mechanism, etc., and a new ironmaking process are presented in this article. Ultrafine ore concentrate with a high amount of stored energy can be produced by mechanical milling, and can be dcoxidated fast below 700℃ by either the coal-based or gas-based process. This novel process has some advantages over others: high productivity, low energy consumption, and environmental friendliness.

  13. Iron

    Science.gov (United States)

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

  14. Research on CO2 Emission Reduction Mechanism of China’s Iron and Steel Industry under Various Emission Reduction Policies

    Directory of Open Access Journals (Sweden)

    Ye Duan

    2017-12-01

    Full Text Available In this paper, a two-stage dynamic game model of China’s iron and steel industry is constructed. Carbon tax levy, product subsidy, carbon capture and sequestration (CCS and other factors are included in the emission reduction mechanism. The effects of emissions reduction and the economic impact of China’s overall steel industry (and that of its six main regions are investigated for the first time under different scenarios. As new findings, we report the following: (1 Not all factors declined. The overall social welfare, consumer surplus, output and emissions decrease with a gradual increase in the reduction target, whereas the carbon tax value, unit value of product subsidies and total subsidies show a rising trend; (2 A combination of multiple emissions reduction policies is more effective than a single policy. With the implementation of a combined policy, regional output polarization has eased; (3 Steel output does not exceed 950 million tons, far below the current peak. These results will help the industry to formulate reasonable emissions reduction and output targets. In short, in effort to eliminate industry poverty and to alleviate overcapacity, the industry should not only adopt the various coordinated reduction policies, but also fully consider regional differences and reduction needs.

  15. Application of natural gas to the direct reduction of iron ore

    Energy Technology Data Exchange (ETDEWEB)

    1975-05-01

    The Gas Committee of the U.N. Economic Commission for Europe evaluated the potentials of natural gas for direct reduction of iron ore. The report, based essentially on that by the Italian representative E. Pasero with comments and observations from experts of the other member countries, indicated the general tendency of the iron and steel industry to use natural gas to reduce production costs by reducing coke consumption. By the end of 1972, gas consumption by these industries was reported at 38.8 billion Btu/ton (10.79 Gcal/m ton) by the Steel Committee of the U.N. Economic Commission at the symposium on the economic and technical aspects of the direct reduction of iron ore, held in September 1972 in Bucharest. In comparison, coke consumption was 9.5 billion Btu/ton (2.64 Gcal/m ton) steel, liquid hydrocarbons 3.1 billion Btu (0.85 Gcal), and electricity 16.1 billion Btu (4.46 Gcal). Natural gas was used mainly for ore reduction and generation of the reducing gas in-shaft furnaces with backdraft heating circulation, fixed-bed furances (Hyl type), and fluidized-bed reactors. Processes include the Midrex (shaft furnace), H.I.B. (fluidized bed), and Novalfer (fluidized bed). These processes are used to obtain 4.5 million tons/yr of iron sponge for the production of steel in electric furnaces. The natural gas outlook for direct reduction of iron will depend on local conditions and fuel availability. Its industrial application has been most successful in mini-steel installations, especially in the U.S., Japan, and Western Europe, and it is recommended for developing countries with no steel-industry basis.

  16. Nitrogen-doped carbon-supported cobalt-iron oxygen reduction catalyst

    Science.gov (United States)

    Zelenay, Piotr; Wu, Gang

    2014-04-29

    A Fe--Co hybrid catalyst for oxygen reaction reduction was prepared by a two part process. The first part involves reacting an ethyleneamine with a cobalt-containing precursor to form a cobalt-containing complex, combining the cobalt-containing complex with an electroconductive carbon supporting material, heating the cobalt-containing complex and carbon supporting material under conditions suitable to convert the cobalt-containing complex and carbon supporting material into a cobalt-containing catalyst support. The second part of the process involves polymerizing an aniline in the presence of said cobalt-containing catalyst support and an iron-containing compound under conditions suitable to form a supported, cobalt-containing, iron-bound polyaniline species, and subjecting said supported, cobalt-containing, iron bound polyaniline species to conditions suitable for producing a Fe--Co hybrid catalyst.

  17. Calcium-assisted reduction of cobalt ferrite nanoparticles for nanostructured iron cobalt with enhanced magnetic performance

    International Nuclear Information System (INIS)

    Qi, B.; Andrew, J. S.; Arnold, D. P.

    2017-01-01

    This paper demonstrates the potential of a calcium-assisted reduction process for synthesizing fine-grain (~100 nm) metal alloys from metal oxide nanoparticles. To demonstrate the process, an iron cobalt alloy (Fe_6_6Co_3_4) is obtained by hydrogen annealing 7-nm cobalt ferrite (CoFe_2O_4) nanoparticles in the presence of calcium granules. The calcium serves as a strong reducing agent, promoting the phase transition from cobalt ferrite to a metallic iron cobalt alloy, while maintaining high crystallinity. Magnetic measurements demonstrate the annealing temperature is the dominant factor of tuning the grain size and magnetic properties. Annealing at 700 °C for 1 h maximizes the magnetic saturation, up to 2.4 T (235 emu/g), which matches that of bulk iron cobalt.

  18. Calcium-assisted reduction of cobalt ferrite nanoparticles for nanostructured iron cobalt with enhanced magnetic performance

    Energy Technology Data Exchange (ETDEWEB)

    Qi, B. [University of Florida, Interdisciplinary Microsystems Group, Department of Electrical and Computer Engineering (United States); Andrew, J. S. [University of Florida, Department of Materials Science and Engineering (United States); Arnold, D. P., E-mail: darnold@ufl.edu [University of Florida, Interdisciplinary Microsystems Group, Department of Electrical and Computer Engineering (United States)

    2017-03-15

    This paper demonstrates the potential of a calcium-assisted reduction process for synthesizing fine-grain (~100 nm) metal alloys from metal oxide nanoparticles. To demonstrate the process, an iron cobalt alloy (Fe{sub 66}Co{sub 34}) is obtained by hydrogen annealing 7-nm cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles in the presence of calcium granules. The calcium serves as a strong reducing agent, promoting the phase transition from cobalt ferrite to a metallic iron cobalt alloy, while maintaining high crystallinity. Magnetic measurements demonstrate the annealing temperature is the dominant factor of tuning the grain size and magnetic properties. Annealing at 700 °C for 1 h maximizes the magnetic saturation, up to 2.4 T (235 emu/g), which matches that of bulk iron cobalt.

  19. In situ reduction of as-prepared γ-Iron Oxide Nanoparticles

    DEFF Research Database (Denmark)

    Garbus, Pelle Gorm; Ahlburg, Jakob; Christensen, Mogens

    -ray diffraction measurement. The as-prepared maghemite nanoparticles were synthesized by the continuous decomposition of solutes in supercritical hydrothermal flow synthesis [3, 4]. The reagent used was ferric ammonium citrate (C6H8O7•xFe(III)•yNH3) that under hydrothermal flow synthesis decomposes into the γ......-iron oxide Fe2O3. The reduction of maghemite to body centered cubic (BCC) iron does not go through a detectable intermediate state.1.Jensen, K.M., et al., Mechanisms for iron oxide formation under hydrothermal conditions: an in situ total scattering study. ACS nano, 2014. 8(10): p. 10704-10714.2.Andersen, H...

  20. Treating thalassemia major-related iron overload: the role of deferiprone

    Directory of Open Access Journals (Sweden)

    Berdoukas V

    2012-10-01

    Full Text Available Vasilios Berdoukas,1 Kallistheni Farmaki,2 Susan Carson,1 John Wood,3 Thomas Coates11Division of Hematology/Oncology, Children's Hospital Los Angeles, Los Angeles, CA, USA; 2Thalassemia Unit, General Hospital of Corinth, Corinth, Greece; 3Division of Cardiology, Children's Hospital Los Angeles, Los Angeles, CA, USAAbstract: Over the last 20 years, management for thalassemia major has improved to the point where we predict that patients' life expectancy will approach that of the normal population. These outcomes result from safer blood transfusions, the availability of three iron chelators, new imaging techniques that allow specific organ assessment of the degree of iron overload, and improvement in the treatment of hepatitis. In October 2011, the Food and Drug Administration licensed deferiprone, further increasing the available choices for iron chelation in the US. The ability to prescribe any of the three chelators as well as their combinations has led to more effective reduction of total body iron. The ability to determine the amount of iron in the liver and heart by magnetic resonance imaging allows the prescription of the most appropriate chelation regime for patients and to reconsider what our aims with respect to total body iron should be. Recent evidence from Europe has shown that by normalizing iron stores not only are new morbidities prevented but also reversal of many complications such as cardiac failure, hypothyroidism, hypogonadism, impaired glucose tolerance, and type 2 diabetes can occur, improving survival and patients' quality of life. The most effective way to achieve normal iron stores seems to be with the combination of deferoxamine and deferiprone. Furthermore, outcomes should continue to improve in the future. Starting relative intensive chelation in younger children may prevent short stature and abnormal pubertal maturation as well as other iron-related morbidities. Also, further information should become available on the

  1. Frequency-Weighted Balancing Related Controller Reduction

    OpenAIRE

    Varga, Andras; Anderson, Brian D.O.

    2002-01-01

    The efficient solution of a class of controller approximation problems by using frequency-weighted balancing related model reduction approaches is considered. It is shown that for certain standard performance and stability enforcing frequency-weights, the computation of the frequency-weighted controllability and observability grammians can be done by solving reduced order Lyapunov equations regardless the controller itself is stable or unstable. The new approach can be used in conjunction wit...

  2. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.-C. [Graduate Institute of Environmental Engineering, National Central University, Chungli, Taiwan 32001 (China); Tseng, D.-H. [Graduate Institute of Environmental Engineering, National Central University, Chungli, Taiwan 32001 (China)]. E-mail: dhtseng@ncuen.ncu.edu.tw; Wang, C.-Y. [Graduate Institute of Environmental Engineering, National Central University, Chungli, Taiwan 32001 (China)

    2006-08-25

    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 ({gamma}-Fe{sub 2}O{sub 3}) to the more hydrated goethite ({alpha}-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{sub 3}O{sub 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{sup 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.

  4. Nitrogen loss from anaerobic ammonium oxidation coupled to Iron(III) reduction in a riparian zone.

    Science.gov (United States)

    Ding, Bangjing; Li, Zhengkui; Qin, Yunbin

    2017-12-01

    Anaerobic ammonium oxidation coupled to iron(III) reduction (termed Feammox) is a recently discovered pathway of nitrogen cycling. However, little is known about the pathways of N transformation via Feammox process in riparian zones. In this study, evidence for Feammox in riparian zones with or without vegetation cover was demonstrated using isotope tracing technique and high-throughput sequencing technology. The results showed that Feammox could occur in riparian zones, and demonstrated that N 2 directly from Feammox was dominant Feammox pathway. The Feammox rates in vegetated soil samples was 0.32-0.37 mg N kg -1 d -1 , which is higher than that in un-vegetated soil samples (0.20 mg N kg -1 d -1 ). Moreover, the growth of vegetation led to a 4.99-6.41% increase in the abundance of iron reducing bacteria (Anaeromyxobacter, Pseudomonas and Geobacter) and iron reducing bacteria play an essential role in Feammox process. An estimated loss of 23.7-43.9 kg N ha -1 year -1 was associated with Feammox in the examined riparian zone. Overall, the co-occurrence of ammonium oxidation and iron reduction suggest that Feammox can play an essential role in the pathway of nitrogen removal in riparian zones. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. The role of microbial iron reduction in the formation of Proterozoic molar tooth structures

    Science.gov (United States)

    Hodgskiss, Malcolm S. W.; Kunzmann, Marcus; Poirier, André; Halverson, Galen P.

    2018-01-01

    Molar tooth structures are poorly understood early diagenetic, microspar-filled voids in clay-rich carbonate sediments. They are a common structure in sedimentary successions dating from 2600-720 Ma, but do not occur in rocks older or younger, with the exception of two isolated Ediacaran occurrences. Despite being locally volumetrically significant in carbonate rocks of this age, their formation and disappearance in the geological record remain enigmatic. Here we present iron isotope data, supported by carbon and oxygen isotopes, major and minor element concentrations, and total organic carbon and sulphur contents for 87 samples from units in ten different basins spanning ca. 1900-635 Ma. The iron isotope composition of molar tooth structures is almost always lighter (modal depletion of 2‰) than the carbonate or residue components in the host sediment. We interpret the isotopically light iron in molar tooth structures to have been produced by dissimilatory iron reduction utilising Fe-rich smectites and Fe-oxyhydroxides in the upper sediment column. The microbial conversion of smectite to illite results in a volume reduction of clay minerals (∼30%) while simultaneously increasing pore water alkalinity. When coupled with wave loading, this biogeochemical process is a viable mechanism to produce voids and subsequently precipitate carbonate minerals. The disappearance of molar tooth structures in the mid-Neoproterozoic is likely linked to a combination of a decrease in smectite abundance, a decline in the marine DIC reservoir, and an increase in the concentration of O2 in shallow seawater.

  6. The effect of diluting ruthenium by iron in Ru{sub x}Se{sub y} catalyst for oxygen reduction

    Energy Technology Data Exchange (ETDEWEB)

    Delacote, Cyril [Laboratory of Electrocatalysis, CNRS, University of Poitiers, F-86022 Poitiers Cedex (France); CEISAM, CNRS, University of Nantes, F-44322 Nantes Cedex 3 (France); Lewera, Adam [University of Warsaw, Department of Chemistry, ul. Pasteura 1, 02-093 Warsaw (Poland); Pisarek, Marcin [Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warsaw (Poland); Kulesza, Pawel J. [University of Warsaw, Department of Chemistry, ul. Pasteura 1, 02-093 Warsaw (Poland); Zelenay, Piotr [Materials Physics and Applications, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Alonso-Vante, Nicolas, E-mail: nicolas.alonso.vante@univ-poitiers.f [Laboratory of Electrocatalysis, CNRS, University of Poitiers, F-86022 Poitiers Cedex (France)

    2010-11-01

    This study has focused on the synthesis of novel oxygen reduction reaction (ORR) chalcogenide catalysts, with Ru partially replaced by Fe in a cluster-type Ru{sub x}Se{sub y}. The catalysts were obtained by thermal decomposition of Ru{sub 3}(CO){sub 12} and Fe(CO){sub 5} in the presence of Se. As indicated by the XPS data, the composition of catalyst nanoparticles depends on the solvent used (either p-xylene or dichlorobenzene). The presence of iron in synthesized catalysts has been confirmed by both EDAX and XPS. Voltammetric activation of the catalysts results in a partial removal of iron and unreacted selenium from the surface. The ORR performance of electrochemically pre-treated catalysts was evaluated using rotating disk and ring-disk electrodes in a sulfuric acid solution. No major change in the ORR mechanism relative to the Se/Ru catalyst has been observed with Fe-containing catalysts.

  7. Reduction of ferric iron by acidophilic heterotrophic bacteria: evidence for constitutive and inducible enzyme systems in Acidiphilium spp.

    Science.gov (United States)

    Johnson, D B; Bridge, T A M

    2002-01-01

    To compare the abilities of two obligately acidophilic heterotrophic bacteria, Acidiphilium acidophilum and Acidiphilium SJH, to reduce ferric iron to ferrous when grown under different culture conditions. Bacteria were grown in batch culture, under different aeration status, and in the presence of either ferrous or ferric iron. The specific rates of ferric iron reduction by fermenter-grown Acidiphilium SJH were unaffected by dissolved oxygen (DO) concentrations, while iron reduction by A. acidophilum was highly dependent on DO concentrations in the growth media. The ionic form of iron present (ferrous or ferric) had a minimal effect on the abilities of harvested cells to reduce ferric iron. Whole cell protein profiles of Acidiphilium SJH were very similar, regardless of the DO status of the growth medium, while additional proteins were present in A. acidophilum grown microaerobically compared with aerobically-grown cells. The dissimilatory reduction of ferric iron is constitutive in Acidiphilium SJH while it is inducible in A. acidophilum. Ferric iron reduction by Acidiphilium spp. may occur in oxygen-containing as well as anoxic acidic environments. This will detract from the effectiveness of bioremediation systems where removal of iron from polluted waters is mediated via oxidation and precipitation of the metal.

  8. Biostimulation of Iron Reduction and Uranium Immobilization: Microbial and Mineralogical Controls

    International Nuclear Information System (INIS)

    Joel E. Kostka

    2008-01-01

    This project represented a joint effort between Florida State University (FSU), Rutgers University (RU), and the University of Illinois (U of I). FSU served as the lead institution and Dr. J.E. Kostka was responsible for project coordination, integration, and deliverables. This project was designed to elucidate the microbial ecology and geochemistry of metal reduction in subsurface environments at the U.S. DOE-NABIR Field Research Center at Oak Ridge, Tennessee (ORFRC). Our objectives were to: (1) characterize the dominant iron minerals and related geochemical parameters likely to limit U(VI) speciation, (2) directly quantify reaction rates and pathways of microbial respiration (terminal-electron-accepting) processes which control subsurface sediment chemistry, and (3) identify and enumerate the organisms mediating U(VI) transformation. A total of 31 publications and 47 seminars or meeting presentations were completed under this project. One M.S. thesis (by Nadia North) and a Ph.D. dissertation (by Lainie Petrie-Edwards) were completed at FSU during fall of 2003 and spring of 2005, respectively. Ph.D. students, Denise Akob and Thomas Gihring have continued the student involvement in this research since fall of 2004. All of the above FSU graduate students were heavily involved in the research, as evidenced by their regular attendance at PI meetings and ORFRC workshops

  9. In Situ UV-Visible Assessment of Iron-Based High-Temperature Water-Gas Shift Catalysts Promoted with Lanthana: An Extent of Reduction Study

    Directory of Open Access Journals (Sweden)

    Basseem B. Hallac

    2018-02-01

    Full Text Available The extent of reduction of unsupported iron-based high-temperature water-gas shift catalysts with small (<5 wt % lanthana contents was studied using UV-visible spectroscopy. Temperature- programmed reduction measurements showed that lanthana content higher than 0.5 wt % increased the extent of reduction to metallic Fe, while 0.5 wt % of lanthana facilitated the reduction to Fe3O4. In situ measurements on the iron oxide catalysts using mass and UV-visible spectroscopies permitted the quantification of the extent of reduction under temperature-programmed reduction and high-temperature water-gas shift conditions. The oxidation states were successfully calibrated against normalized absorbance spectra of visible light using the Kubelka-Munk theory. The normalized absorbance relative to the fully oxidized Fe2O3 increased as the extent of reduction increased. XANES suggested that the average bulk iron oxidation state during the water-gas shift reaction was Fe+2.57 for the catalyst with no lanthana and Fe+2.54 for the catalysts with 1 wt % lanthana. However, the UV-vis spectra suggest that the surface oxidation state of iron would be Fe+2.31 for the catalyst with 1 wt % lanthana if the oxidation state of iron in the catalyst with 0 wt % lanthana were Fe+2.57. The findings of this paper emphasize the importance of surface sensitive UV-visible spectroscopy for determining the extent of catalyst reduction during operation. The paper highlights the potential to use bench-scale UV-visible spectroscopy to study the surface chemistry of catalysts instead of less-available synchrotron X-ray radiation facilities.

  10. Iron deficiency and overload in relation to nutrition

    NARCIS (Netherlands)

    Spanjersberg MQI; Jansen EHJM; LEO

    2000-01-01

    Nutritional iron intake in the Netherlands has been reviewed with respect to both iron deficiency and iron overload. In general, iron intake and iron status in the Netherlands are adequate and therefore no change in nutrition policy is required. The following aspects and developments, however, need

  11. Bacterial assimilation reduction of iron in the treatment of non-metallics

    Directory of Open Access Journals (Sweden)

    Peter Malachovský

    2005-11-01

    Full Text Available Natural non-metallics, including granitoide and quartz sands, often contain iron which decreases the whiteness of these raw materials. Insoluble Fe3+ in these samples could be reduced to soluble Fe2+ by bacteria of Bacillus spp. and Saccharomyces spp. The leaching effect, observed by the measurement of Fe2+concentration in a solution, showed higher activities of a bacterial kind isolated from the Bajkal lake and also by using of yeast Saccharomyces sp. during bioleaching of quartz sands. However, allkinds of Bacillus spp. isolated from the Slovak deposit and from Bajkal lake were very active in the iron reduction during bioleaching of the feldspar raw material. This metal was efficiently removed from quartz sands as documented by the Fe2O3 decrease (from 0,317 % to 0,126 % and from feldpars raw materials by the Fe2O3 decrease (from 0,288 % to 0,115 % after bioleaching. The whiteness of these non-metallics was increased during a visual comparison of samples before and after bioleaching but samples contain selected magnetic particles. A removal of iron as well as a release of iron minerals from silicate matrix should increase the effect of the magnetic separation and should give a product which is suitable for industrial applications.

  12. Heterogeneous kinetics of the reduction of chromium (VI) by elemental iron

    International Nuclear Information System (INIS)

    Fiuza, Antonio; Silva, Aurora; Carvalho, Goreti; Fuente, Antonio V. de la; Delerue-Matos, Cristina

    2010-01-01

    Zero valent iron (ZVI) has been extensively used as a reactive medium for the reduction of Cr(VI) to Cr(III) in reactive permeable barriers. The kinetic rate depends strongly on the superficial oxidation of the iron particles used and the preliminary washing of ZVI increases the rate. The reaction has been primarily modelled using a pseudo-first-order kinetics which is inappropriate for a heterogeneous reaction. We assumed a shrinking particle type model where the kinetic rate is proportional to the available iron surface area, to the initial volume of solution and to the chromium concentration raised to a power α which is the order of the chemical reaction occurring at surface. We assumed α = 2/3 based on the likeness to the shrinking particle models with spherical symmetry. Kinetics studies were performed in order to evaluate the suitability of this approach. The influence of the following parameters was experimentally studied: initial available surface area, chromium concentration, temperature and pH. The assumed order for the reaction was confirmed. In addition, the rate constant was calculated from data obtained in different operating conditions. Digital pictures of iron balls were periodically taken and the image treatment allowed for establishing the time evolution of their size distribution.

  13. The anaerobic degradation of organic matter in Danish coastal sediments: iron reduction, manganese reduction, and sulfate reduction

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene; Thamdrup, B; Hansen, Jens Würgler

    1993-01-01

    ). In the deep portion of the basin, surface Mn enrichments reached 3.5 wt%, and Mn reduction was the only important anaerobic carbon oxidation process in the upper 10 cm of the sediment. In the less Mn-rich sediments from intermediate depths in the basin, Fe reduction ranged from somewhat less, to far more...... speculate that in shallow sediments of the Skagerrak, surface Mn oxides are present in a somewhat reduced oxidation level (deep basin....

  14. Utilization of waste polyethylene terephthalate as a reducing agent in the reduction of iron ore composite pellets

    Science.gov (United States)

    Polat, Gökhan; Birol, Burak; Sarıdede, Muhlis Nezihi

    2014-08-01

    The increasing consumption of plastics inevitably results in increasing amounts of waste plastics. Because of their long degradation periods, these wastes negatively affect the natural environment. Numerous studies have been conducted to recycle and eliminate waste plastics. The potential for recycling waste plastics in the iron and steel industry has been underestimated; the high C and H contents of plastics may make them suitable as alternative reductants in the reduction process of iron ore. This study aims to substitute plastic wastes for coal in reduction melting process and to investigate their performance during reduction at high temperature. We used a common type of waste plastic, polyethylene terephthalate (PET), because of its high carbon and hydrogen contents. Composite pellets containing PET wastes, coke, and magnetite iron ore were reduced at selected temperatures of 1400 and 1450°C for reduction time from 2 to 10 min to investigate the reduction melting behavior of these pellets. The results showed that an increased temperature and reduction time increased the reduction ratio of the pellets. The optimum experimental conditions for obtaining metallic iron (iron nuggets) were reduction at 1450°C for 10 min using composite pellets containing 60% PET and 40% coke.

  15. Asymmetric Chemoenzymatic Reductive Acylation of Ketones by a Combined Iron-Catalyzed Hydrogenation-Racemization and Enzymatic Resolution Cascade

    KAUST Repository

    El-Sepelgy, Osama; Brzozowska, Aleksandra; Rueping, Magnus

    2017-01-01

    . By merging the iron-catalyzed redox reactions with enantioselective enzymatic acylations a wide range of benzylic, aliphatic and (hetero)aromatic ketones, as well as diketones, were reductively acylated. The corresponding products were isolated with high

  16. REDUCTIVE DEHALOGENATION OF HALOMETHANES IN IRON- AND SULFATE-REDUCING SEDIMENTS. 1. REACTIVITY PATTERN ANALYSIS

    Science.gov (United States)

    The incorporation of reductive transformations into environmental fate models requires the characterization of natural reductants in well-characterized sediments and aquifer materials. For this purpose, reactivity patterns (i.e., the range and relative order of reactivity) for a...

  17. Study on electrolytic reduction with controlled oxygen flow for iron from molten oxide slag containing FeO

    Directory of Open Access Journals (Sweden)

    Gao Y.M.

    2013-01-01

    Full Text Available A ZrO2-based solid membrane electrolytic cell with controlled oxygen flow was constructed: graphite rod /[O]Fe+C saturated / ZrO2(MgO/(FeO slag/iron crucible. The feasibility of extraction of iron from molten oxide slag containing FeO at an applied voltage was investigated by means of the electrolytic cell. The effects of some important process factors on the FeO electrolytic reduction with the controlled oxygen flow were discussed. The results show that: solid iron can be extracted from molten oxide slag containing FeO at 1450ºC and an applied potential of 4V. These factors, such as precipitation and growth of solid iron dendrites, change of the cathode active area on the inner wall of the iron crucible and ion diffusion flux in the molten slag may affect the electrochemical reaction rate. The reduction for Fe2+ ions mainly appears on new iron dendrites of the iron crucible cathode, and a very small amount of iron are also formed on the MSZ (2.18% MgO partially stabilized zirconia tube/slag interface due to electronic conductance of MSZ tube. Internal electronic current through MSZ tube may change direction at earlier and later electrolytic reduction stage. It has a role of promoting electrolytic reduction for FeO in the molten slag at the earlier stage, but will lower the current efficiency at the later stage. The final reduction ratio of FeO in the molten slag can achieve 99%. A novel electrolytic method with controlled oxygen flow for iron from the molten oxide slag containing FeO was proposed. The theory of electrolytic reduction with the controlled oxygen flow was developed.

  18. Inhibition of sulfate reduction by iron, cadmium and sulfide in granular sludge

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Silva, Blanca M. [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a. Seccion, 78216, San Luis Potosi, S.L.P. (Mexico); Briones-Gallardo, Roberto [Facultad de Ingenieria-Instituto de Metalurgia, Universidad Autonoma de San Luis Potosi, Sierra Leona 550, Lomas 2a. Seccion, 78210, San Luis Potosi, S.L.P. (Mexico); Razo-Flores, Elias [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a. Seccion, 78216, San Luis Potosi, S.L.P. (Mexico); Celis, Lourdes B., E-mail: celis@ipicyt.edu.mx [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a. Seccion, 78216, San Luis Potosi, S.L.P. (Mexico)

    2009-12-15

    This study investigated the inhibition effect of iron, cadmium and sulfide on the substrate utilization rate of sulfate reducing granular sludge. A series of batch experiments in a UASB reactor were conducted with different concentrations of iron (Fe{sup 2+}, 4.0-8.5 mM), cadmium (Cd{sup 2+}, 0.53-3.0 mM) and sulfide (4.2-10.6 mM), the reactor was fed with ethanol at 1 g chemical oxygen demand (COD)/L and sulfate to yield a COD/SO{sub 4}{sup 2-} (g/g) ratio of 0.5. The addition of iron, up to a concentration of 8.1 mM, had a positive effect on the substrate utilization rate which increased 40% compared to the rate obtained without metal addition (0.25 g COD/g VSS-d). Nonetheless, iron concentration of 8.5 mM inhibited the specific substrate utilization rate by 57% compared to the substrate utilization rate obtained in the batch amended with 4.0 mM Fe{sup 2+} (0.44 g COD/g VSS-d). Cadmium had a negative effect on the specific substrate utilization rate at the concentrations tested; at 3.0 mM Cd{sup 2+} the substrate utilization rate was inhibited by 44% compared with the substrate utilization rate without metal addition. Cadmium precipitation with sulfide did not decrease the inhibition of cadmium on sulfate reduction. These results could have important practical implications mainly when considering the application of the sulfate reducing process to treat effluents with high concentrations of sulfate and dissolved metals such as iron and cadmium.

  19. Inhibition of sulfate reduction by iron, cadmium and sulfide in granular sludge

    International Nuclear Information System (INIS)

    Gonzalez-Silva, Blanca M.; Briones-Gallardo, Roberto; Razo-Flores, Elias; Celis, Lourdes B.

    2009-01-01

    This study investigated the inhibition effect of iron, cadmium and sulfide on the substrate utilization rate of sulfate reducing granular sludge. A series of batch experiments in a UASB reactor were conducted with different concentrations of iron (Fe 2+ , 4.0-8.5 mM), cadmium (Cd 2+ , 0.53-3.0 mM) and sulfide (4.2-10.6 mM), the reactor was fed with ethanol at 1 g chemical oxygen demand (COD)/L and sulfate to yield a COD/SO 4 2- (g/g) ratio of 0.5. The addition of iron, up to a concentration of 8.1 mM, had a positive effect on the substrate utilization rate which increased 40% compared to the rate obtained without metal addition (0.25 g COD/g VSS-d). Nonetheless, iron concentration of 8.5 mM inhibited the specific substrate utilization rate by 57% compared to the substrate utilization rate obtained in the batch amended with 4.0 mM Fe 2+ (0.44 g COD/g VSS-d). Cadmium had a negative effect on the specific substrate utilization rate at the concentrations tested; at 3.0 mM Cd 2+ the substrate utilization rate was inhibited by 44% compared with the substrate utilization rate without metal addition. Cadmium precipitation with sulfide did not decrease the inhibition of cadmium on sulfate reduction. These results could have important practical implications mainly when considering the application of the sulfate reducing process to treat effluents with high concentrations of sulfate and dissolved metals such as iron and cadmium.

  20. Detoxification of PAX-21 ammunitions wastewater by zero-valent iron for microbial reduction of perchlorate

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Se Chang; Cha, Daniel K. [Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716 (United States); Kim, Byung J. [U.S. Army Engineer Research and Development Center, Champaign, IL 61826-9005 (United States); Oh, Seok-Young, E-mail: quartzoh@ulsan.ac.kr [Department of Civil and Environmental Engineering, University of Ulsan, Ulsan 680-749 (Korea, Republic of)

    2011-08-30

    Highlights: {yields} Ammonium perchlorate, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4-dinitroanisole (DNAN) are the major constituents of PAX-21. {yields} DNAN is identified as the primary toxicant responsible for inhibiting the activity of perchlorate reducing bacteria. {yields} Iron treatment not only removes energetic compounds but also eliminates the toxic constituents that inhibit the subsequent microbial process. - Abstract: US Army and the Department of Defense (DoD) facilities generate perchlorate (ClO{sub 4}{sup -}) from munitions manufacturing and demilitarization processes. Ammonium perchlorate is one of the main constituents in Army's new main charge melt-pour energetic, PAX-21. In addition to ammonium perchlorate, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4-dinitroanisole (DNAN) are the major constituents of PAX-21. In order to evaluate microbial perchlorate reduction as a practical option for the treatment of perchlorate in PAX-21 wastewater, we conducted biodegradation experiments using glucose as the primary sources of electrons and carbon. Batch experiments showed that negligible perchlorate was removed in microbial reactors containing PAX-21 wastewater while control bottles containing seed bacteria and glucose rapidly and completely removed perchlorate. These results suggested that the constituents in PAX-21 wastewater may be toxic to perchlorate reducing bacteria. A series of batch toxicity test was conducted to identify the toxic constituents in PAX-21 and DNAN was identified as the primary toxicant responsible for inhibiting the activity of perchlorate reducing bacteria. It was hypothesized that pretreatment of PAX-21 by zero-valent iron granules will transform toxic constituents in PAX-21 wastewater to non-toxic products. We observed complete reduction of DNAN to 2,4-diaminoanisole (DAAN) and RDX to formaldehyde in abiotic iron reduction study. After a 3-day acclimation period, perchlorate in iron-treated PAX-21

  1. Relation between Serum Ferritin and Iron Parameters with Preeclampsia

    Directory of Open Access Journals (Sweden)

    Robabeh Taheripanah

    2007-06-01

    Full Text Available Objective: Preeclampsia is one of the most important complications of pregnancy that is associated with increased morbidity and mortality. The aim of this study was to investigate the relation between serum iron status and ferritin with pre-eclampsia. Materials and Methods: This case control study evaluated 33 preeclamptic patients and 33 normal pregnant women before parturition in Imam Hossein hospital, from March 2003 till March 2004. Anemia, diabetes and multiple pregnancies were excluded from the study. Blood samples were taken before delivery and patients with HELLP syndrome were considered separately.  Data were analyzed using the SPSS software and P value <0.05 was considered statistically significant. T-test, chi-square and Fisher exact test were used.  Results: The mean of serum iron level in case and control group was 79.9±32.4µg/dl and 88.6±40.8 µg/dl, respectively (NS. TIBC was 443.4±55.0 µmol/l and 383.7±63.6 µmol/l in normal patients and preeclamptics respectively (P = 0.002. Mean serum ferritin was 32.1±16.2 ng/dl in control group and 123.8±46.1 ng/dl in preeclamptics (P<0.001. No meaningful relation was observed between hematocrit, ferritin and iron. Conclusions: Ferritin increases and TIBC decreases in preeclampsia regardless of hepatic function. It seems that elevated serum ferritin (as an oxidative stress can accelerate vascular damage. So, routine iron supplementation in preeclamptic women is questationable.

  2. Uranium(VI) Reduction by Nanoscale Zerovalent Iron in Anoxic Batch Systems

    International Nuclear Information System (INIS)

    Yan, Sen; Hua, Bin; Bao, Zhengyu; Yang, John; Liu, Chongxuan; Deng, Baolin

    2010-01-01

    This study investigated the influences of pH, bicarbonate, and calcium on U(VI) adsorption and reduction by synthetic nanosize zero valent iron (nano Fe 0 ) particles under an anoxic condition. The results showed that about 87.1%, 82.7% and 78.3% of U(VI) could be reduced within 96 hours in the presence of 10 mM bicarbonate at pHs 6.92, 8.03 and 9.03, respectively. The rates of U(VI) reduction and adsorption by nano Fe 0 , however, varied significantly with increasing pH and concentrations of bicarbonate and/or calcium. Solid phase analysis by X-ray photoelectron spectroscopy confirmed the formation of UO 2 and iron (hydr)oxides as a result of the redox interactions between adsorbed U(VI) and nano Fe 0 . This study highlights the potential important role of groundwater chemical composition in controlling the rates of U(VI) reductive immobilization using nano Fe 0 in subsurface environments.

  3. Iron solubility related to particle sulfur content in source emission and ambient fine particles.

    Science.gov (United States)

    Oakes, M; Ingall, E D; Lai, B; Shafer, M M; Hays, M D; Liu, Z G; Russell, A G; Weber, R J

    2012-06-19

    The chemical factors influencing iron solubility (soluble iron/total iron) were investigated in source emission (e.g., biomass burning, coal fly ash, mineral dust, and mobile exhaust) and ambient (Atlanta, GA) fine particles (PM2.5). Chemical properties (speciation and mixing state) of iron-containing particles were characterized using X-ray absorption near edge structure (XANES) spectroscopy and micro-X-ray fluorescence measurements. Bulk iron solubility (soluble iron/total iron) of the samples was quantified by leaching experiments. Major differences were observed in iron solubility in source emission samples, ranging from low solubility (iron solubility did not correspond to silicon content or Fe(II) content. However, source emission and ambient samples with high iron solubility corresponded to the sulfur content observed in single particles. A similar correspondence between bulk iron solubility and bulk sulfate content in a series of Atlanta PM2.5 fine particle samples (N = 358) further supported this trend. In addition, results of linear combination fitting experiments show the presence of iron sulfates in several high iron solubility source emission and ambient PM2.5 samples. These results suggest that the sulfate content (related to the presence of iron sulfates and/or acid-processing mechanisms by H(2)SO(4)) of iron-containing particles is an important proxy for iron solubility.

  4. Relation of erythrocyte and iron indices to oral cancer growth

    International Nuclear Information System (INIS)

    Bhattathiri, Vasudevaru Narayanan

    2001-01-01

    Background and purpose: Anaemia is known to influence prognosis of head and neck cancer patients, but how anaemia and tumour growth influences each other is not clear. The present study investigates the relation of erythrocyte and iron indices of oral cancer patients to primary tumour size (Tsize), invasiveness and lymph node involvement. Materials and methods: The haemoglobin (Hb), erythrocyte count (RBC), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), Serum iron (SFe), transferrin iron-binding capacity (TIBC) and transferrin saturation (%Fe) were evaluated in 217 untreated patients with epidermoid cancer of the bucco-gingivo-palatine area. The association of erythrocyte and iron indices with sex, tumour size groups, invasion of adjacent structures and lymph node involvement, as well as the relation of SFe to Hb were analyzed. Results: Most of the patients were anaemic in terms of Hb (63%), RBC (43%) and PCV (48.4%) but almost all had normal or higher MCH (97.3%) and MCV (93.3%) though MCHC was less than normal in 70.7%. Normal or higher SFe was seen in nearly 70% and TIBC in 45% of patients. Hb, RBC and PCV were significantly lower in women, but there was no difference between men and women in the case of MCV, MCH and MCHC. Primary tumour size showed negative association with Hb, RBC and PCV but positive association with MCH ( 4 cm: 31. 7 pg; P=0.04) and MCHC ( 4 cm: 32.1; P=0.006). MCV, SFe, TIBC and %Fe did not show any relation to primary tumour size. None of the indices had any relation to invasion of adjacent structures or lymph node involvement. MCH, MCHC and MCV were not different in men and women but women had significantly lower Hb, RBC and PCV. The SFe showed poor correlation with Hb. Conclusions: The negative association of Hb, RBC and PCV with tumour size is most likely due to chronic RBC destruction, probably tumour induced, with the products of

  5. Kinetics and Products of Chromium(VI) Reduction by Iron(II/III)-Bearing Clay Minerals.

    Science.gov (United States)

    Joe-Wong, Claresta; Brown, Gordon E; Maher, Kate

    2017-09-05

    Hexavalent chromium is a water-soluble pollutant, the mobility of which can be controlled by reduction of Cr(VI) to less soluble, environmentally benign Cr(III). Iron(II/III)-bearing clay minerals are widespread potential reductants of Cr(VI), but the kinetics and pathways of Cr(VI) reduction by such clay minerals are poorly understood. We reacted aqueous Cr(VI) with two abiotically reduced clay minerals: an Fe-poor montmorillonite and an Fe-rich nontronite. The effects of ionic strength, pH, total Fe content, and the fraction of reduced structural Fe(II) [Fe(II)/Fe(total)] were examined. The last variable had the largest effect on Cr(VI) reduction kinetics: for both clay minerals, the rate constant of Cr(VI) reduction varies by more than 3 orders of magnitude with Fe(II)/Fe(total) and is described by a linear free energy relationship. Under all conditions examined, Cr and Fe K-edge X-ray absorption near-edge structure spectra show that the main Cr-bearing product is a Cr(III)-hydroxide and that Fe remains in the clay structure after reacting with Cr(VI). This study helps to quantify our understanding of the kinetics of Cr(VI) reduction by Fe(II/III)-bearing clay minerals and may improve predictions of Cr(VI) behavior in subsurface environments.

  6. Magnetic and Moessbauer-spectroscopic studies of iron-clusters in zeolites. [Reduction of ferrous ions

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, F; Gunsser, W; Knappwost, A [Hamburg Univ. (F.R. Germany). Inst. fuer Physikalische Chemie

    1975-12-01

    Iron clusters have been prepared within zeolite holes by reduction of zeolites containing ferrous ions. The diameter of these particles must therefore be smaller that 13 A. They are superparamagnetic and their Moessbauer spectra show no HFS, even at 4K. The temperature dependence of the magnetic susceptibility of the unreduced zeolites obeys a Curie-Weiss law with p/sub eff/ = 4.45 ..mu..B and THETA = 105K. The Weiss curves of the reduced samples lie distinctly below those of the bulk material.

  7. Operational experience on reduction of feedwater iron and liquid radwaste input for Kuosheng Nuclear Power Plant

    International Nuclear Information System (INIS)

    Wen, T.J.; Huang, Theresa Chen; Liu, Wen Tsung; Liu, T.C.; Shyur, Tzu Sheng; Shen, S.C.

    1998-01-01

    Other than cobalt alloys, or low cobalt materials, feedwater iron content plays an important role in crud activation and transport causing the growth of out-of-core radiation fields and associated with radwaste generation. Before installing prefilter in the upstream of condensate deep-bed demineralizer, increasing demand for suspended solid removal required new backwash and regeneration technique in Kuosheng Nuclear Power Plant. At steady state full power operation, the average iron concentration in condensate demineralizer influent was 8-15 ppb. Considering both the necessity of backwash and reduction of liquid radwaste input, several actions had been taken to promote the crud removal capabilities without using ultrasonic resin cleaner and controlled feedwater iron content between 0.5 and 2.0 ppb. This modified resin backwash technique would also generate minimum liquid radwaste. Meanwhile, significant efforts have been made to promote the quality of waste water by carefully control input streams as well as backwash modification to reduce liquid radwaste generation. The daily quantity of liquid radwaste has decreased dramatically in the past two years and is effectively controlled under the expected average daily input of design basis. (author)

  8. Application of nonisothermal kinetic techniques on the reduction of three commercial iron ore agglomerates

    International Nuclear Information System (INIS)

    Bedolla, E.; Leon, C.A.; Aguilar, E.A.

    1997-01-01

    The mechanism of reduction of iron ore agglomerates by both isothermal and nonisothermal TG studies was investigated, and the work was complemented with the structural characterization of the total and partially reacted samples. Three different commercial hematite pellets were studied. The mechanisms of reduction were obtained under isothermal conditions, resulting in a fitting to chemical reaction models. Nonisothermal reduction was carried out using a TGA system (CAHN TG-171) from 600 to 1,000 degree centigree maintaining a lineal heating rate of 4,7 and 10 degree centigree/min, and the reducing atmospheres used were H 2 (100%) and H 2 -CO(95:5). The kinetic parameters were evaluated by Coats and Redfern, Dixit and Ray and Prakash and Ray techniques. It was found that the lower the heating rate, the higher the reduction degree and the higher activation energy. The activation energy for reduction with the mixture H 2 -CO was always higher than that obtained with pure H 2 . (Author)

  9. Electrochemical preparation of iron cuboid nanoparticles and their catalytic properties for nitrite reduction

    International Nuclear Information System (INIS)

    Chen Yanxin; Chen Shengpei; Chen Qingsong; Zhou Zhiyou; Sun Shigang

    2008-01-01

    Iron cuboid nanoparticles supported on glassy carbon (denoted nm-Fe/GC) were prepared by electrochemical deposition under cyclic voltammetric (CV) conditions. The structure and composition of the Fe nanomaterials were characterized by scanning electron microscopy (SEM), selected area electron diffraction (SAED), X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDX). The results demonstrated that the Fe cuboid nanoparticles are dispersed discretely on GC substrate with an average size ca. 171 nm, and confirmed that the electrochemical synthesized nanocubes are single crystals of pure Fe. The catalytic properties of the Fe cuboid nanoparticles towards nitrite electroreduction were investigated, and enhanced electrocatalytic activity of the Fe nanocubes has been determined. In comparison with the data obtained on a bulk-Fe electrode, the onset potential of nitrite reduction on nm-Fe/GC is positively sifted by 100 mV, and the steady reduction current density is enhanced about 2.4-3.2 times

  10. Carbothermic Reduction of Nickeliferous Laterite Ores for Nickel Pig Iron Production in China: A Review

    Science.gov (United States)

    Rao, Mingjun; Li, Guanghui; Jiang, Tao; Luo, Jun; Zhang, Yuanbo; Fan, Xiaohui

    2013-11-01

    Both the consumption and production of crude stainless steel in China rank first in the world. In 2011, the nickel production in China amounted to 446 kilotons, with the proportion of electrolytic nickel and nickel pig iron (NPI) registering 41.5% and 56.5%, respectively. NPI is a low-cost feedstock for stainless steel production when used as a substitute for electrolytic nickel. The existing commercial NPI production processes such as blast furnace smelting, rotary kiln-electric furnace smelting, and Krupp-Renn (Nipon Yakin Oheyama) processes are discussed. As low-temperature (below 1300°C) reduction of nickeliferous laterite ores followed by magnetic separation could provide an alternative avenue without smelting at high temperature (~1500°C) for producing ferronickel with low cost, the fundamentals and recent developments of the low-temperature reduction of nickeliferous laterite ores are reviewed.

  11. Bifunctional (cyclopentadienone)iron-tricarbonyl complexes: Synthesis, computational studies and application in reductive amination

    KAUST Repository

    Moulin, Solenne

    2013-11-15

    Reductive amination under hydrogen pressure is a valuable process in organic chemistry to access amine derivatives from aldehydes or ketones. Knölker\\'s complex has been shown to be an efficient iron catalyst in this reaction. To determine the influence of the substituents on the cyclopentadienone ancillary ligand, a series of modified Knölker\\'s complexes was synthesised and fully characterised. These complexes were also transformed into their analogous acetonitrile iron-dicarbonyl complexes. Catalytic activities of these complexes were evaluated and compared in a model reaction. The scope of this reaction is also reported. For mechanistic insights, deuterium-labelling experiments and DFT calculations were undertaken and are also presented. Festival of amination: Two series of modified Knölker\\'s complexes were synthesised and applied in the reductive amination of various carbonyl derivatives with primary or secondary amines (see scheme, TIPS = triisopropylsilyl). For a mechanistic insight, deuterium-labelling experiments and DFT calculations were undertaken and are also presented. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Relative Bioavailability of Iron in Bangladeshi Traditional Meals Prepared with Iron-Fortified Lentil Dal

    Directory of Open Access Journals (Sweden)

    Rajib Podder

    2018-03-01

    Full Text Available Due to low Fe bioavailability and low consumption per meal, lentil must be fortified to contribute significant bioavailable Fe in the Bangladeshi diet. Moreover, since red lentil is dehulled prior to consumption, an opportunity exists at this point to fortify lentil with Fe. Thus, in the present study, lentil was Fe-fortified (using a fortificant Fe concentration of 2800 µg g−1 and used in 30 traditional Bangladeshi meals with broad differences in concentrations of iron, phytic acid (PA, and relative Fe bioavailability (RFeB%. Fortification with NaFeEDTA increased the iron concentration in lentil from 60 to 439 µg g−1 and resulted in a 79% increase in the amount of available Fe as estimated by Caco-2 cell ferritin formation. Phytic acid levels were reduced from 6.2 to 4.6 mg g−1 when fortified lentil was added, thereby reducing the PA:Fe molar ratio from 8.8 to 0.9. This effect was presumably due to dephytinization of fortified lentil during the fortification process. A significant (p ≤ 0.01 Pearson correlation was observed between Fe concentration and RFeB% and between RFeB% and PA:Fe molar ratio in meals with fortified lentil, but not for the meal with unfortified lentil. In conclusion, fortified lentil can contribute significant bioavailable Fe to populations at risk of Fe deficiency.

  13. Relative Bioavailability of Iron in Bangladeshi Traditional Meals Prepared with Iron-Fortified Lentil Dal.

    Science.gov (United States)

    Podder, Rajib; M DellaValle, Diane; T Tyler, Robert; P Glahn, Raymond; Tako, Elad; Vandenberg, Albert

    2018-03-15

    Due to low Fe bioavailability and low consumption per meal, lentil must be fortified to contribute significant bioavailable Fe in the Bangladeshi diet. Moreover, since red lentil is dehulled prior to consumption, an opportunity exists at this point to fortify lentil with Fe. Thus, in the present study, lentil was Fe-fortified (using a fortificant Fe concentration of 2800 µg g -1 ) and used in 30 traditional Bangladeshi meals with broad differences in concentrations of iron, phytic acid (PA), and relative Fe bioavailability (RFeB%). Fortification with NaFeEDTA increased the iron concentration in lentil from 60 to 439 µg g -1 and resulted in a 79% increase in the amount of available Fe as estimated by Caco-2 cell ferritin formation. Phytic acid levels were reduced from 6.2 to 4.6 mg g -1 when fortified lentil was added, thereby reducing the PA:Fe molar ratio from 8.8 to 0.9. This effect was presumably due to dephytinization of fortified lentil during the fortification process. A significant ( p ≤ 0.01) Pearson correlation was observed between Fe concentration and RFeB% and between RFeB% and PA:Fe molar ratio in meals with fortified lentil, but not for the meal with unfortified lentil. In conclusion, fortified lentil can contribute significant bioavailable Fe to populations at risk of Fe deficiency.

  14. Impact of natural organic matter coatings on the microbial reduction of iron oxides

    Science.gov (United States)

    Poggenburg, Christine; Mikutta, Robert; Schippers, Axel; Dohrmann, Reiner; Guggenberger, Georg

    2018-03-01

    Iron (Fe) oxyhydroxides are important constituents of the soil mineral phase known to stabilize organic matter (OM) under oxic conditions. In an anoxic milieu, however, these Fe-organic associations are exposed to microbial reduction, releasing OM into soil solution. At present, only few studies have addressed the influence of adsorbed natural OM (NOM) on the reductive dissolution of Fe oxyhydroxides. This study therefore examined the impact of both the composition and concentration of adsorbed NOM on microbial Fe reduction with regard to (i) electron shuttling, (ii) complexation of Fe(II,III), (iii) surface site coverage and/or pore blockage, and (iv) aggregation. Adsorption complexes with varying carbon loadings were synthesized using different Fe oxyhydroxides (ferrihydrite, lepidocrocite, goethite, hematite, magnetite) and NOM of different origin (extracellular polymeric substances from Bacillus subtilis, OM extracted from soil Oi and Oa horizons). The adsorption complexes were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), N2 gas adsorption, electrophoretic mobility and particle size measurements, and OM desorption. Incubation experiments under anaerobic conditions were conducted for 16 days comparing two different strains of dissimilatory Fe(III)-reducing bacteria (Shewanella putrefaciens, Geobacter metallireducens). Mineral transformation during reduction was assessed via XRD and FTIR. Microbial reduction of the pure Fe oxyhydroxides was controlled by the specific surface area (SSA) and solubility of the minerals. For Shewanella putrefaciens, the Fe reduction of adsorption complexes strongly correlated with the concentration of potentially usable electron-shuttling molecules for NOM concentrations <2 mg C L-1, whereas for Geobacter metallireducens, Fe reduction depended on the particle size and thus aggregation of the adsorption complexes. These diverging results suggest that

  15. Decreased serum hepcidin concentration correlates with brain iron deposition in patients with HBV-related cirrhosis.

    Directory of Open Access Journals (Sweden)

    Dong Lin

    Full Text Available PURPOSE: Excessive brain iron accumulation contributes to cognitive impairments in hepatitis B virus (HBV-related cirrhotic patients. The underlying mechanism remains unclear. Hepcidin, a liver-produced, 25-aminoacid peptide, is the major regulator of systemic iron metabolism. Abnormal hepcidin level is a key factor in some body iron accumulation or deficiency disorders, especially in those associated with liver diseases. Our study was aimed to explore the relationship between brain iron content in patients with HBV-related cirrhosis and serum hepcidin level. METHODS: Seventy HBV-related cirrhotic patients and forty age- sex-matched healthy controls were enrolled. Brain iron content was quantified by susceptibility weighted phase imaging technique. Serum hepcidin as well as serum iron, serum transferrin, ferritin, soluble transferrin receptor, total iron binding capacity, and transferrin saturation were tested in thirty cirrhotic patients and nineteen healthy controls. Pearson correlation analysis was performed to investigate correlation between brain iron concentrations and serum hepcidin, or other iron parameters. RESULTS: Cirrhotic patients had increased brain iron accumulation compared to controls in the left red nuclear, the bilateral substantia nigra, the bilateral thalamus, the right caudate, and the right putamen. Cirrhotic patients had significantly decreased serum hepcidin concentration, as well as lower serum transferring level, lower total iron binding capacity and higher transferrin saturation, compared to controls. Serum hepcidin level negatively correlated with the iron content in the right caudate, while serum ferritin level positively correlated with the iron content in the bilateral putamen in cirrhotic patients. CONCLUSIONS: Decreased serum hepcidin level correlated with excessive iron accumulation in the basal ganglia in HBV-related cirrhotic patients. Our results indicated that systemic iron overload underlined regional

  16. Understanding the role of multiheme cytochromes in iron(III) reduction and arsenic mobilization by Shewanella sp. ANA-3

    Science.gov (United States)

    Reyes, C.; Duenas, R.; Saltikov, C.

    2006-12-01

    The reduction of Fe (III) to Fe (II) and of arsenate (As (V)) to arsenite (As (III)) by Fe (III) reducing and As (V) respiring prokaryotes such as the bacterium Shewanella sp. ANA-3 may contribute to arsenic mobilization in aquifers contaminated with arsenic, specifically in places such as Bangladesh. Under oxic conditions As (V) predominates and is often adsorbed onto mineral surfaces such as amorphous ferrihydrite. However, under anoxic conditions As (III) predominates, sorbs to fewer minerals, and has a greater hydrologic mobility compared to As (V). The genetic mechanism underlying arsenic release from subsurface material most likely involves a combination of respiratory gene clusters (e.g. mtr/omc and arr). In this study, we are investigating the genetic pathways underlying arsenic mobilization. We have generated various mutations in the mtr/omc gene cluster, which encodes several outermembrane decaheme c-type cytochromes. Deletions in one mtr/omc gene did not eliminate iron reduction. However, strains carrying multiple gene deletions were greatly impaired in iron reduction abilities. Work is currently underway to generate combinations of iron reduction and arsenate reduction single and double mutants that will be used to investigate microbial mobilization of arsenic in flow-through columns containing As (V)-HFO coated sand. This work will address the importance of arsenate reduction and iron reduction in the mobilization of arsenic.

  17. Nicotianamine synthase overexpression positively modulates iron homeostasis-related genes in high iron rice

    Directory of Open Access Journals (Sweden)

    Meng eWang

    2013-05-01

    Full Text Available Nearly one-third of the world population, mostly women and children, suffer from iron malnutrition and its consequences, such as anemia or impaired mental development. Biofortification of rice, which is a staple crop for nearly half of the world’s population, can significantly contribute in alleviating iron deficiency. NFP rice (transgenic rice expressing nicotianamine synthase, ferritin and phytase genes has a more than six-fold increase in iron content in polished rice grains, resulting from the synergistic action of nicotianamine synthase (NAS and ferritin transgenes. We investigated iron homeostasis in NFP plants by analyzing the expression of 28 endogenous rice genes known to be involved in the homeostasis of iron and other metals, in iron-deficient and iron-sufficient conditions. RNA was collected from different tissues (roots, flag leaves, grains and at three developmental stages during grain filling. NFP plants showed increased sensitivity to iron-deficiency conditions and changes in the expression of endogenous genes involved in nicotianamine (NA metabolism, in comparison to their non-transgenic siblings. Elevated transcript levels were detected in NFP plants for several iron transporters. In contrast, expression of OsYSL2, which encodes a member of Yellow Stripe-like protein family, and a transporter of the NA-Fe(II complex was reduced in NFP plants under low iron conditions, indicating that expression of OsYSL2 is regulated by the endogenous iron status. Expression of the transgenes did not significantly affect overall iron homeostasis in NFP plants, which establishes the engineered push-pull mechanism as a suitable strategy to increase rice endosperm iron content.

  18. The relative dietary importance of haem and non-haem iron

    International Nuclear Information System (INIS)

    Bezwoda, W.R.; Bothwell, T.H.; Charlton, R.W.; Torrance, J.D.; MacPhail, A.P.; Derman, D.P.; Mayet, F.

    1983-01-01

    A study was undertaken to find out the relative amounts of haem and non-haem iron absorbed from meals in which varying amounts of these substances were present. Four meals, each containing 6 mg of iron but with varying ratios of haem and non-haem iron, were fed to two groups of subjects, each group receiving two meals. The geometric mean percentage absorption of non-haem iron decreased from 18,0% (SD range 14,6-22,3%) to 6,4% (SD range 3,4-11,8%) as the non-haem iron content of the meal increased from 1,52 mg to 5,72 mg - there was therefore little variation in the actual amounts of non-haem iron absorbed from the different meals. In contrast, the geometric mean absorption of haem iron was approximately 20% from all four meals, although the haem iron content varied between 0,28 mg and 4,48 mg. The amount of haem iron absorbed was thus a linear function of the amount of haem iron in the meal. Two points emerged from the study. Firstly, the relative importance of haem iron in overall iron nutrition was confirmed. Secondly, the fact that the pattern of absorption in relation to dosage was so different from haem iron and non-haem iron suggested that a controlling mechanism for non-haem iron absorption may be located at the mucosal surface. This conclusion is based on the fact that haem iron, the percentage absorption of which was found to be independent of the size of the dose, is absorped into the mucosal cell when still contained within the porphyrin ring and the iron thus bypasses some controlling mechanism at the mucosal border

  19. Asymmetric Chemoenzymatic Reductive Acylation of Ketones by a Combined Iron-Catalyzed Hydrogenation-Racemization and Enzymatic Resolution Cascade

    KAUST Repository

    El-Sepelgy, Osama

    2017-02-28

    A general and practical process for the conversion of prochiral ketones into the corresponding chiral acetates has been realized. An iron carbonyl complex is reported to catalyze the hydrogenation-dehydrogenation-hydrogenation of prochiral ketones. By merging the iron-catalyzed redox reactions with enantioselective enzymatic acylations a wide range of benzylic, aliphatic and (hetero)aromatic ketones, as well as diketones, were reductively acylated. The corresponding products were isolated with high yields and enantioselectivities. The use of an iron catalyst together with molecular hydrogen as the hydrogen donor and readily available ethyl acetate as acyl donor make this cascade process highly interesting in terms of both economic value and environmental credentials.

  20. Iron

    DEFF Research Database (Denmark)

    Hansen, Jakob Bondo; Moen, I W; Mandrup-Poulsen, T

    2014-01-01

    and discuss recent evidence, suggesting that iron is a key pathogenic factor in both type 1 and type 2 diabetes with a focus on inflammatory pathways. Pro-inflammatory cytokine-induced β-cell death is not fully understood, but may include iron-induced ROS formation resulting in dedifferentiation by activation...... of transcription factors, activation of the mitochondrial apoptotic machinery or of other cell death mechanisms. The pro-inflammatory cytokine IL-1β facilitates divalent metal transporter 1 (DMT1)-induced β-cell iron uptake and consequently ROS formation and apoptosis, and we propose that this mechanism provides...

  1. Biological reduction of iron to the elemental state from ochre deposits of Skelton Beck in Northeast England

    Directory of Open Access Journals (Sweden)

    Pattanathu K S M Rahman

    2014-06-01

    Full Text Available Ochre, consequence of acid mine drainage, is iron oxides-rich soil pigments that can be found in the water drainage from historic base metal and coal mines. The anaerobic strains of Geobacter sulfurreducens and Shewanella denitrificans were used for the microbial reduction of iron from samples of ochre collected from Skelton Beck (Saltburn Orange River, NZ 66738 21588 in Northeast England. The aim of the research was to determine the ability of the two anaerobic bacteria to reduce the iron present in ochre and to determine the rate of the reduction process. The physico-chemical changes in the ochre sample after the microbial reduction process were observed by the production of zero-valent iron which was later confirmed by the detection of elemental Fe in XRD spectrum. The XRF results revealed that 69.16% and 84.82% of iron oxide can be reduced using G. sulfurreducens and S. denitrificans respectively after 8 days of incubation. These results could provide the basis for the development of a biohydrometallurgical process for the production of elemental iron from ochre sediments.

  2. Iron

    Science.gov (United States)

    ... Share: Search the ODS website Submit Search NIH Office of Dietary Supplements Consumer Datos en español Health ... eating a variety of foods, including the following: Lean meat, seafood, and poultry. Iron-fortified breakfast cereals ...

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

    Science.gov (United States)

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

    1993-01-01

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

  4. Unveiling the high-activity origin of single-atom iron catalysts for oxygen reduction reaction.

    Science.gov (United States)

    Yang, Liu; Cheng, Daojian; Xu, Haoxiang; Zeng, Xiaofei; Wan, Xin; Shui, Jianglan; Xiang, Zhonghua; Cao, Dapeng

    2018-06-26

    It is still a grand challenge to develop a highly efficient nonprecious-metal electrocatalyst to replace the Pt-based catalysts for oxygen reduction reaction (ORR). Here, we propose a surfactant-assisted method to synthesize single-atom iron catalysts (SA-Fe/NG). The half-wave potential of SA-Fe/NG is only 30 mV less than 20% Pt/C in acidic medium, while it is 30 mV superior to 20% Pt/C in alkaline medium. Moreover, SA-Fe/NG shows extremely high stability with only 12 mV and 15 mV negative shifts after 5,000 cycles in acidic and alkaline media, respectively. Impressively, the SA-Fe/NG-based acidic proton exchange membrane fuel cell (PEMFC) exhibits a high power density of 823 mW cm -2 Combining experimental results and density-functional theory (DFT) calculations, we further reveal that the origin of high-ORR activity of SA-Fe/NG is from the Fe-pyrrolic-N species, because such molecular incorporation is the key, leading to the active site increase in an order of magnitude which successfully clarifies the bottleneck puzzle of why a small amount of iron in the SA-Fe catalysts can exhibit extremely superior ORR activity.

  5. Oxidation of a Dimethoxyhydroquinone by Ferrihydrite and Goethite Nanoparticles: Iron Reduction versus Surface Catalysis.

    Science.gov (United States)

    Krumina, Lelde; Lyngsie, Gry; Tunlid, Anders; Persson, Per

    2017-08-15

    Hydroquinones are important mediators of electron transfer reactions in soils with a capability to reduce Fe(III) minerals and molecular oxygen, and thereby generating Fenton chemistry reagents. This study focused on 2,6-dimethoxy hydroquinone (2,6-DMHQ), an analogue to a common fungal metabolite, and its reaction with ferrihydrite and goethite under variable pH and oxygen concentrations. Combined wet-chemical and spectroscopic analyses showed that both minerals effectively oxidized 2,6-DMHQ in the presence of oxygen. Under anaerobic conditions the first-order oxidation rate constants decreased by one to several orders of magnitude depending on pH and mineral. Comparison between aerobic and anaerobic results showed that ferrihydrite promoted 2,6-DMHQ oxidation both via reductive dissolution and heterogeneous catalysis while goethite mainly caused catalytic oxidation. These results were in agreement with changes in the reduction potential (E H ) of the Fe(III) oxide/Fe(II) aq redox couple as a function of dissolved Fe(II) where E H of goethite was lower than ferrihydrite at any given Fe(II) concentration, which makes ferrihydrite more prone to reductive dissolution by the 2,6-DMBQ/2,6-DMHQ redox couple. This study showed that reactions between hydroquinones and iron oxides could produce favorable conditions for formation of reactive oxygen species, which are required for nonenzymatic Fenton-based decomposition of soil organic matter.

  6. Reduction and Immobilization of Potassium Permanganate on Iron Oxide Catalyst by Fluidized-Bed Crystallization Technology

    Directory of Open Access Journals (Sweden)

    Guang-Xia Li

    2012-03-01

    Full Text Available A manganese immobilization technology in a fluidized-bed reactor (FBR was developed by using a waste iron oxide (i.e., BT-3 as catalyst which is a by-product from the fluidized-bed Fenton reaction (FBR-Fenton. It was found that BT-3 could easily reduce potassium permanganate (KMnO4 to MnO2. Furthermore, MnO2 could accumulate on the surface of BT-3 catalyst to form a new Fe-Mn oxide. Laboratory experiments were carried out to investigate the KMnO4-reduction mechanism, including the effect of KMnO4 concentration, BT-3 dosage, and operational solution pH. The results showed that the pH solution was a significant factor in the reduction of KMnO4. At the optimum level, pHf 6, KMnO4 was virtually reduced in 10 min. A pseudo-first order reaction was employed to describe the reduction rate of KMnO4.

  7. Longevity of granular iron in groundwater treatment processes: solution composition effects on reduction of organohalides and nitroaromatic compounds.

    Science.gov (United States)

    Klausen, Jörg; Vikesland, Peter J; Kohn, Tamar; Burris, David R; Ball, William P; Roberts, A Lynn

    2003-03-15

    Although granular iron permeable reactive barriers (PRBs) are increasingly employed to contain subsurface contaminants, information pertaining to system longevity is sparse. The present investigation redresses this situation by examining the long-term effects of carbonate, silica, chloride, and natural organic matter (NOM) on reactivity of Master Builders iron toward organohalides and nitroaromatic contaminants. Six columns were operated for 1100 days (approximately 4500 pore volumes) and five others for 407 days (approximately 1800 pore volumes). Nine were continuously exposed to mixtures of contaminant species, while the other two were only intermittently exposed in order to differentiate deactivation induced by water (and inorganic cosolutes) from that resulting from contaminant reduction. Contaminants investigated were trichloroethylene, 1,2,3-trichloropropane, 1,1-dichloroethane, 2-nitrotoluene, 4-nitroacetophenone, and 4-nitroanisole. Column reactivity declined substantially over the first 300 days and was dependent on the feed solution chemistry. High carbonate concentrations enhanced reactivity slightly within the first 90 days but produced poorer performance over the long term. Both silica and NOM adversely affected reactivity, while chloride evinced a somewhat mixed effect. Observed contrasts in relative reactivities suggest that trichloroethylene, 1,2,3-trichloropropane, and nitroaromatic compounds all react at different types of reactive sites. Our results indicate that differences in groundwater chemistry should be considered in the PRB design process.

  8. Role of a gas phase in the kinetics of zinc and iron reduction with carbon from slag melts

    Science.gov (United States)

    Chumarev, V. M.; Selivanov, E. N.

    2013-03-01

    The influence of the mass transfer conditions in the gas phase having formed at the carbon-slag melt interface on CO regeneration is approximately estimated in the framework of a two-stage scheme of metal reduction from slag melts by carbon. The effect of zinc vapors on the combined reduction of iron and zinc from slags is considered. The influence of the slag composition and temperature on the critical concentration of zinc oxide above which no iron forms as an individual phase is explained.

  9. Properties and effects of remaining carbon from waste plastics gasifying on iron scale reduction.

    Science.gov (United States)

    Zhang, Chongmin; Chen, Shuwen; Miao, Xincheng; Yuan, Hao

    2011-06-01

    The carbonous activities of three kinds of carbon-bearing materials gasified from plastics were tested with coal coke as reference. The results showed that the carbonous activities of these remaining carbon-bearing materials were higher than that of coal-coke. Besides, the fractal analyses showed that the porosities of remaining carbon-bearing materials were higher than that of coal-coke. It revealed that these kinds of remaining carbon-bearing materials are conducive to improve the kinetics conditions of gas-solid phase reaction in iron scale reduction. Copyright © 2011 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  10. Investigations on pollutant reduction in iron murd from the Schlema-Alberoda and Poehla pits

    International Nuclear Information System (INIS)

    Knappik, R.; Fleischer, K.; Meyer, J.

    1998-01-01

    By examplary investigations with two typical iron muds from the Schlema-Alberoda and Poehla pits it was examined whether a reducing agent in flushing water is able to contribute to changes in flushing water quality by dissolution of muds. Two closed circuit apparatuses are used, in which soluted sodium dithionite as reducing agent was added periodically and the reaction progress was monitored by in-situ-measuring of redox potential and pH as well as by sampling. The experiments were planned as to apply the results for worst-case assessment. Two very different typs of mining muds regarding to their mobilizing behavior were detected. The reaction consists of the following steps: consumption of oxygen in solution, mobilization of Fe and Mn, increasing reduction of Fe(III) to Fe(II) in the solid phase. The extent of concentration change of Fe(II), Mn, As, U and other components in flushing water at conditioning as well as depending on geochemical milieu (number of reduction steps) was discussed. On experimental conditions a complete dissolution of all iron compounds is impossible even at excess of reducing agent. On the base of estimed substance potential and reaction turn-over this results may be transferred to conditions in the mines. A partial dissolution at optimal hydrodynamic conditions does not result in mobilization of pollutants (uranium, radium, arsene) but in formation of Fe(II) and Mn(II), the extent depending on potential of mud and reducing agent. The redox buffer range will not be exceeded. (orig.)

  11. Variation of iron redox kinetics and its relation with molecular composition of standard humic substances at circumneutral pH

    OpenAIRE

    Lee, Ying Ping; Fujii, Manabu; Kikuchi, Tetsuro; Terao, Koumei; Yoshimura, Chihiro

    2017-01-01

    Oxidation and reduction kinetics of iron (Fe) and proportion of steady-state Fe(II) concentration relative to total dissolved Fe (steady-state Fe(II) fraction) were investigated in the presence of various types of standard humic substances (HS) with particular emphasis on the photochemical and thermal reduction of Fe(III) and oxidation of Fe(II) by dissolved oxygen (O2) and hydrogen peroxide (H2O2) at circumneutral pH (pH 7-8). Rates of Fe(III) reduction were spectrophotometrically determined...

  12. Rotating collapse of stellar iron cores in general relativity

    International Nuclear Information System (INIS)

    Ott, C D; Dimmelmeier, H; Marek, A; Janka, H-T; Zink, B; Hawke, I; Schnetter, E

    2007-01-01

    We present results from the first 2 + 1 and 3 + 1 simulations of the collapse of rotating stellar iron cores in general relativity employing a finite-temperature equation of state and an approximate treatment of deleptonization during collapse. We compare full 3 + 1 and conformally-flat spacetime evolution methods and find that the conformally-flat treatment is sufficiently accurate for the core-collapse supernova problem. We focus on the gravitational wave (GW) emission from rotating collapse, core bounce and early postbounce phases. Our results indicate that the GW signature of these phases is much more generic than previously estimated. In addition, we track the growth of a nonaxisymmetric instability of dominant m = 1 character in two of our models that leads to prolonged narrow-band GW emission at ∼920-930 Hz over several tens of milliseconds

  13. Sharply higher rates of iron deficiency in obese Mexican women and children are predicted by obesity-related inflammation rather than by differences in dietary iron intake

    NARCIS (Netherlands)

    Cepeda-Lopez, A.C.; Osendarp, S.J.M.; Boonstra, A.; Aeberli, I.; Gonzalez-Salazar, F.; Feskens, E.J.M.; Villalpando, S.; Zimmermann, M.B.

    2011-01-01

    Background: Obese individuals may be at increased risk of iron deficiency (ID), but it is unclear whether this is due to poor dietary iron intakes or to adiposity-related inflammation. Objective: The aim of this study was to examine the relations between body mass index (BMI), dietary iron, and

  14. Phase change of iron ore reduction process using EFB as reducing agent at 900-1200°C

    Science.gov (United States)

    Purwanto, H.; Salleh, H. M.; Rozhan, A. N.; Mohamad, A. S.; Zakiyuddin, A.

    2018-04-01

    Treatment of low grade iron ore involved reduction of oxygen in iron oxide by using reductant such as carbon monoxide or hydrogen gas. Presently, carboneous materials such as coke/coal are widely used as a source to provide reducing gas, but some problem arises from this material as the gas can harm the environments. Therefore, empty fruit bunch biomass from oil palm becomes an alternative to replace the usage of coke/coal as their major composition is carbon and hydrogen. The idea of replacing coke with biomass will reduce the amount of carbon dioxide release as biomass is a carbon neutral and renewable source, and at the same time abundance of waste from oil palm industries can be overcome. Therefore, the aim of this research is to upgrade the low grade iron with reducibility more than 50% being used in iron and steel making. In this research, low grade iron ore are mixed together with EFB then is making into composite pellet before being reduced at certain parameter chosen. The variables involved in this research is composition EFB (10%, 30% and 50%), temperature (1000°C, 1100°C and 1200°C) and reduction time is fixed with 30 minutes. From the experiment conducted, the highest reducibility achieved is 76.37% at temperature 1200°C. While XRD analysis shows the existence of metallic iron phase started to form at 1000°C with composition of 30% of EFB. Meanwhile, from magnetization test show that at 1200°C the highest magnetic susceptibility is achieved as the dominance phase at 1200°C is metallic phase. Therefore it is an interesting alternative to replace coke with biomass for reducing agent in upgrading low grade iron into workable ores.

  15. Excess iron: considerations related to development and early growth.

    Science.gov (United States)

    Wessling-Resnick, Marianne

    2017-12-01

    What effects might arise from early life exposures to high iron? This review considers the specific effects of high iron on the brain, stem cells, and the process of erythropoiesis and identifies gaps in our knowledge of what molecular damage may be incurred by oxidative stress that is imparted by high iron status in early life. Specific areas to enhance research on this topic include the following: longitudinal behavioral studies of children to test associations between iron exposures and mood, emotion, cognition, and memory; animal studies to determine epigenetic changes that reprogram brain development and metabolic changes in early life that could be followed through the life course; and the establishment of human epigenetic markers of iron exposures and oxidative stress that could be monitored for early origins of adult chronic diseases. In addition, efforts to understand how iron exposure influences stem cell biology could be enhanced by establishing platforms to collect biological specimens, including umbilical cord blood and amniotic fluid, to be made available to the research community. At the molecular level, there is a need to better understand stress erythropoiesis and changes in iron metabolism during pregnancy and development, especially with respect to regulatory control under high iron conditions that might promote ineffective erythropoiesis and iron-loading anemia. These investigations should focus not only on factors such as hepcidin and erythroferrone but should also include newly identified interactions between transferrin receptor-2 and the erythropoietin receptor. Finally, despite our understanding that several key micronutrients (e.g., vitamin A, copper, manganese, and zinc) support iron's function in erythropoiesis, how these nutrients interact remains, to our knowledge, unknown. It is necessary to consider many factors when formulating recommendations on iron supplementation. © 2017 American Society for Nutrition.

  16. RECOVERY OF IRON FROM LOW-GRADE HEMATITE ORE USING COAL-BASED DIRECT REDUCTION FOLLOWED BY MAGNETIC SEPARATION

    Directory of Open Access Journals (Sweden)

    N. Alavifard

    2016-09-01

    Full Text Available In the present work, iron recovery from a low-grade hematite ore (containing less than 40% iron, which is not applicable in common methods of ironmaking, was studied. Non-coking coal was used as reducing agent. Reduction experiments were performed under various coal to hematite ratios and temperatures. Reduction degree was calculated using the gravimetric method. Reduced samples were subjected to magnetic separation followed by X-ray diffraction analysis. Total iron content, degree of metallization and recovery efficiency in magnetic part were determined by quantitative chemical analysis, which were obtained about 82%, 95% and 64% respectively under optimal conditions. CaO as an additive improved ore reducibility and separation efficiency. The microstructure of reduced samples and final products were analyzed by scanning electron microscopy. Final product with a high degree of metallization can be used in steel making furnaces and charging of blast furnaces which can improve production efficiency and decrease coke usage.

  17. Effect of Ca-Fe oxides additives on NOx reduction in iron ore sintering

    Institute of Scientific and Technical Information of China (English)

    Zhi-yuan Yu; Xiao-hui Fan; Min Gan; Xu-ling Chen

    2017-01-01

    As the emission control regulations get stricter, the NOx reduction in the sintering process becomes an important environmental concern owing to its role in the formation of photochemical smog and acid rain. The NOx emissions from the sintering machine account for 48% of total amount from the iron and steel industry.Thus, it is essential to reduce NOx emissions from the sintering machine, for the achievement of clean production of sinter.Ca-Fe oxides, serving as the main binding phase in the sinter, are therefore used as additives into the sintering mixture to reduce NOx emissions.The results show that the NOx re-duction ratio achieves 27.76% with 8% Ca-Fe oxides additives since the Ca-Fe oxides can advance the ig-nition and inhibit the nitrogen oxidation compared with the conventional condition.Meanwhile, the exist-ence of Ca-Fe oxides was beneficial to the sinter quality since they were typical low melting point com-pounds.The optimal mass fraction of Ca-Fe oxides additives should be less than 8% since the permeability of sintering bed was significantly decreased with a further increase of the Ca-Fe oxides fines, inhibiting the mineralization reaction of sintering mixture.Additionally, the appropriate particle size can be obtained when mixing an equal amount of Ca-Fe oxides additives of -0.5 mm and 0.5-3.0 mm in size.

  18. Evolution of the near-UV emission spectrum associated with the reduction process in microwave iron making.

    Science.gov (United States)

    Matsubara, Akihiro; Takayama, Sadatsugu; Okajima, Shigeki; Sato, Motoyasu

    2008-01-01

    The structure of the emission spectrum in the near-UV range (240 nm-310 nm) changes drastically from the continuous spectrum to a discrete line spectrum with increasing sample temperature during the carbothermic reduction of magnetite in a 2.45 GHz microwave multimode furnace. The continuous spectrum can be assigned as a cathodoluminescence of magnetite. The dynamic evolution of the spectrum from continuous to discrete represents the progress of the reduction from magnetite to iron.

  19. Comparative study of reactions between µ-nitrido- or µ-oxo-bridged iron tetrasulfophthalocyanines and sulfur-containing reductants

    Directory of Open Access Journals (Sweden)

    Dereven’kov Ilia A.

    2013-01-01

    Full Text Available A comparative study of reactivity of μ-nitrido- and μ-oxo-dimers of iron tetrasulfophthalocyanine has been performed in aqueous solutions of various acidity. The substantially higher stability of nitrido-bridged structure under both strongly acidic and strongly alkaline environments was demonstrated. Reactions of the complexes with sulfur-containing reductants (sodium dithionite, thiourea dioxide, sodium hydroxymethanesulfinate, L-cysteine has been studied. Differences in reduction processes were explained.

  20. Synthesis of iron nanoparticles with poly(1-vinylpyrrolidone-co-vinyl acetate) and its application to nitrate reduction

    DEFF Research Database (Denmark)

    Lee, Nara; Choi, Kyunghoon; Uthuppu, Basil

    2014-01-01

    This study aimed to synthesize dispersed and reactive nanoscale zero-valent iron (nZVI) with poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA), nontoxic and biodegradable stabilizer. The nZVI used for the experiments was prepared by reduction of ferric solution in the presence of PVP/VA with spe...

  1. Influence of Carbon Sources and Electron Shuttles on Ferric Iron Reduction by Cellulomonas sp. Strain ES6

    Energy Technology Data Exchange (ETDEWEB)

    Dr Robin Gerlach; Erin K. Field; Sridhar Viamajala; Brent M. Peyton; William A. Apel; Al B. Cunningham

    2011-09-01

    Microbially reduced iron minerals can reductively transform a variety of contaminants including heavy metals, radionuclides, chlorinated aliphatics, and nitroaromatics. A number of Cellulomonas spp. strains, including strain ES6, isolated from aquifer samples obtained at the U.S. Department of Energy's Hanford site in Washington, have been shown to be capable of reducing Cr(VI), TNT, natural organic matter, and soluble ferric iron [Fe(III)]. This research investigated the ability of Cellulomonas sp. strain ES6 to reduce solid phase and dissolved Fe(III) utilizing different carbon sources and various electron shuttling compounds. Results suggest that Fe(III) reduction by and growth of strain ES6 was dependent upon the type of electron donor, the form of iron present, and the presence of synthetic or natural organic matter, such as anthraquinone-2,6-disulfonate (AQDS) or humic substances. This research suggests that Cellulomonas sp. strain ES6 could play a significant role in metal reduction in the Hanford subsurface and that the choice of carbon source and organic matter addition can allow for independent control of growth and iron reduction activity.

  2. Preliminary characterization and biological reduction of putative biogenic iron oxides (BIOS) from the Tonga-Kermadec Arc, southwest Pacific Ocean.

    Science.gov (United States)

    Langley, S; Igric, P; Takahashi, Y; Sakai, Y; Fortin, D; Hannington, M D; Schwarz-Schampera, U

    2009-01-01

    Sediment samples were obtained from areas of diffuse hydrothermal venting along the seabed in the Tonga sector of the Tonga-Kermadec Arc, southwest Pacific Ocean. Sediments from Volcano 1 and Volcano 19 were analyzed by X-ray diffraction (XRD) and found to be composed primarily of the iron oxyhydroxide mineral, two-line ferrihydrite. XRD also suggested the possible presence of minor amounts of more ordered iron (hydr)oxides (including six-line ferrihydrite, goethite/lepidocrocite and magnetite) in the biogenic iron oxides (BIOS) from Volcano 1; however, Mössbauer spectroscopy failed to detect any mineral phases more crystalline than two-line ferrihydrite. The minerals were precipitated on the surfaces of abundant filamentous microbial structures. Morphologically, some of these structures were similar in appearance to the known iron-oxidizing genus Mariprofundus spp., suggesting that the sediments are composed of biogenic iron oxides. At Volcano 19, an areally extensive, active vent field, the microbial cells appeared to be responsible for the formation of cohesive chimney-like structures of iron oxyhydroxide, 2-3 m in height, whereas at Volcano 1, an older vent field, no chimney-like structures were apparent. Iron reduction of the sediment material (i.e. BIOS) by Shewanella putrefaciens CN32 was measured, in vitro, as the ratio of [total Fe(II)]:[total Fe]. From this parameter, reduction rates were calculated for Volcano 1 BIOS (0.0521 day(-1)), Volcano 19 BIOS (0.0473 day(-1)), and hydrous ferric oxide, a synthetic two-line ferrihydrite (0.0224 day(-1)). Sediments from both BIOS sites were more easily reduced than synthetic ferrihydrite, which suggests that the decrease in effective surface area of the minerals within the sediments (due to the presence of the organic component) does not inhibit subsequent microbial reduction. These results indicate that natural, marine BIOS are easily reduced in the presence of dissimilatory iron-reducing bacteria, and that the

  3. Iron alloy Fischer-tropsch catalysts--1. Oxidation-reduction studies of the Fe-Ni system

    Energy Technology Data Exchange (ETDEWEB)

    Unmuth, E.E.; Schwartz, L.H.; Butt, J.B.

    1980-01-01

    Catalysts containing 5% iron, nickel, or 4:1 iron-nickel on silica were hydrogen-reduced at 425/sup 0/C for 12 or 24 hr, reoxidized in air for 2 or 4 hr, reduced again in hydrogen for 12 hr, and studied at each treatment step by Moessbauer spectroscopy, X-ray diffraction, and temperature-programed desorption. The nickel was reduced directly to the metal, redispersed during the oxidation, and gave 20% smaller particles in the second reduction than in the first reduction. The ..cap alpha..-Fe/sub 2/O/sub 3/ reduced via an Fe/sub 3/O/sub 4/ intermediate and yielded approx. 70% metallic iron and the second reduction produced about the same particle size as the first reduction. The alloy catalyst reduced into a mixture of two phases, a face-centered cubic phase containing approx. 37.5% Ni, i.e., the bulk equilibrium value, and a body-centered cubic phase, and the particle sizes obtained in the first and second reductions were similar. The activation energies for the reduction were determined.

  4. Single Atomic Iron Catalysts for Oxygen Reduction in Acidic Media: Particle Size Control and Thermal Activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hanguang [Department; Hwang, Sooyeon [Center; Wang, Maoyu [School; Feng, Zhenxing [School; Karakalos, Stavros [Department; Luo, Langli [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Qiao, Zhi [Department; Xie, Xiaohong [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Wang, Chongmin [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Su, Dong [Center; Shao, Yuyan [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Wu, Gang [Department

    2017-09-26

    To significantly reduce the cost of proton exchange membrane (PEM) fuel cells, current Pt must be replaced by platinum-metal-group (PGM)-free catalysts for the oxygen reduction reaction (ORR) in acid. We report here a new class of high-performance atomic iron dispersed carbon catalysts through controlled chemical doping of iron ions into zinc-zeolitic imidazolate framework (ZIF), a type of metal-organic framework (MOF). The novel synthetic chemistry enables accurate size control of Fe-doped ZIF catalyst particles with a wide range from 20 to 1000 nm without changing chemical properties, which provides a great opportunity to increase the density of active sites that is determined by the particle size. We elucidated the active site formation mechanism by correlating the chemical and structural changes with thermal activation process for the conversion from Fe-N4 complex containing hydrocarbon networks in ZIF to highly active FeNx sites embedded into carbon. A temperature of 800oC was identified as the critical point to start forming pyridinic nitrogen doping at the edge of the graphitized carbon planes. Further increasing heating temperature to 1100oC leads to increase of graphitic nitrogen, generating possible synergistic effect with FeNx sites to promote ORR activity. The best performing catalyst, which has well-defined particle size around 50 nm and abundance of atomic FeNx sites embedded into carbon structures, achieve a new performance milestone for the ORR in acid including a half-wave potential of 0.85 V vs RHE and only 20 mV loss after 10,000 cycles in O2 saturated H2SO4 electrolyte. The new class PGM-free catalyst with approaching activity to Pt holds great promise for future PEM fuel cells.

  5. Nitrogen-doped graphene-wrapped iron nanofragments for high-performance oxygen reduction electrocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jang Yeol [Korea Institute of Science and Technology, Photo-Electronic Hybrid Research Center (Korea, Republic of); Kim, Na Young [Korea Institute of Science and Technology, Fuel Cell Research Center (Korea, Republic of); Shin, Dong Yun [Chungbuk National University, Department of Environmental Engineering (Korea, Republic of); Park, Hee-Young [Korea Institute of Science and Technology, Fuel Cell Research Center (Korea, Republic of); Lee, Sang-Soo [Korea Institute of Science and Technology, Photo-Electronic Hybrid Research Center (Korea, Republic of); Joon Kwon, S. [Korea Institute of Science and Technology, Nanophotonics Research Center (Korea, Republic of); Lim, Dong-Hee [Chungbuk National University, Department of Environmental Engineering (Korea, Republic of); Bong, Ki Wan [Korea University, Department of Chemical and Biological Engineering (Korea, Republic of); Son, Jeong Gon, E-mail: jgson@kist.re.kr [Korea Institute of Science and Technology, Photo-Electronic Hybrid Research Center (Korea, Republic of); Kim, Jin Young, E-mail: jinykim@kist.re.kr [Korea Institute of Science and Technology, Fuel Cell Research Center (Korea, Republic of)

    2017-03-15

    Transition metals, such as iron (Fe)- or cobalt (Co)-based nanomaterials, are promising electrocatalysts for oxygen reduction reactions (ORR) in fuel cells due to their high theoretical activity and low cost. However, a major challenge to using these metals in place of precious metal catalysts for ORR is their low efficiency and poor stability, thus new concepts and strategies should be needed to address this issue. Here, we report a hybrid aciniform nanostructures of Fe nanofragments embedded in thin nitrogen (N)-doped graphene (Fe@N-G) layers via a heat treatment of graphene oxide-wrapped iron oxide (Fe{sub 2}O{sub 3}) microparticles with melamine. The heat treatment leads to transformation of Fe{sub 2}O{sub 3} microparticles to nanosized zero-valent Fe fragments and formation of core-shell structures of Fe nanofragments and N-doped graphene layers. Thin N-doped graphene layers massively promote electron transfer from the encapsulated metals to the graphene surface, which efficiently optimizes the electronic structure of the graphene surface and thereby triggers ORR activity at the graphene surface. With the synergistic effect arising from the N-doped graphene and Fe nanoparticles with porous aciniform nanostructures, the Fe@N-G hybrid catalyst exhibits high catalytic activity, which was evidenced by high E{sub 1/2} of 0.82 V, onset potential of 0.93 V, and limiting current density of 4.8 mA cm{sup −2} indicating 4-electron ORR, and even exceeds the catalytic stability of the commercial Pt catalyst.

  6. Reconstruction of Extracellular Respiratory Pathways for Iron(III Reduction in Shewanella oneidensis strain MR-1

    Directory of Open Access Journals (Sweden)

    Dan eCoursolle

    2012-02-01

    Full Text Available Shewanella oneidensis strain MR-1 is a facultative anaerobic bacterium capable of respiring a multitude of electron acceptors, many of which require the Mtr respiratory pathway. The core Mtr respiratory pathway includes a periplasmic c-type cytochrome (MtrA, an integral outer membrane β-barrel protein (MtrB and an outer membrane-anchored c-type cytochrome (MtrC. Together, these components facilitate transfer of electrons from the c-type cytochrome CymA in the cytoplasmic membrane to electron acceptors at and beyond the outer membrane. The genes encoding these core proteins have paralogs in the S. oneidensis genome (mtrB and mtrA each have four while mtrC has three and some of the paralogs of mtrC and mtrA are able to form functional Mtr complexes. We demonstrate that of the additional three mtrB paralogs found in the S. oneidensis genome, only MtrE can replace MtrB to form a functional respiratory pathway to soluble iron(III citrate. We also evaluate which mtrC / mtrA paralog pairs (a total of 12 combinations are able to form functional complexes with endogenous levels of mtrB paralog expression. Finally, we reconstruct all possible functional Mtr complexes and test them in a S. oneidensis mutant strain where all paralogs have been eliminated from the genome. We find that each combination tested with the exception of MtrA / MtrE / OmcA is able to reduce iron(III citrate at a level significantly above background. The results presented here have implications towards the evolution of anaerobic extracellular respiration in Shewanella and for future studies looking to increase the rates of substrate reduction for water treatment, bioremediation, or electricity production.

  7. Mercury mobilization and speciation linked to bacterial iron oxide and sulfate reduction: A column study to mimic reactive transfer in an anoxic aquifer.

    Science.gov (United States)

    Hellal, Jennifer; Guédron, Stéphane; Huguet, Lucie; Schäfer, Jörg; Laperche, Valérie; Joulian, Catherine; Lanceleur, Laurent; Burnol, André; Ghestem, Jean-Philippe; Garrido, Francis; Battaglia-Brunet, Fabienne

    2015-09-01

    Mercury (Hg) mobility and speciation in subsurface aquifers is directly linked to its surrounding geochemical and microbial environment. The role of bacteria on Hg speciation (i.e., methylation, demethylation and reduction) is well documented, however little data is available on their impact on Hg mobility. The aim of this study was to test if (i) Hg mobility is due to either direct iron oxide reduction by iron reducing bacteria (IRB) or indirect iron reduction by sulfide produced by sulfate reducing bacteria (SRB), and (ii) to investigate its subsequent fate and speciation. Experiments were carried out in an original column setup combining geochemical and microbiological approaches that mimic an aquifer including an interface of iron-rich and iron depleted zones. Two identical glass columns containing iron oxides spiked with Hg(II) were submitted to (i) direct iron reduction by IRB and (ii) to indirect iron reduction by sulfides produced by SRB. Results show that in both columns Hg was leached and methylated during the height of bacterial activity. In the column where IRB are dominant, Hg methylation and leaching from the column was directly correlated to bacterial iron reduction (i.e., Fe(II) release). In opposition, when SRB are dominant, produced sulfide induced indirect iron oxide reduction and rapid adsorption of leached Hg (or produced methylmercury) on neoformed iron sulfides (e.g., Mackinawite) or its precipitation as HgS. At the end of the SRB column experiment, when iron-oxide reduction was complete, filtered Hg and Fe concentrations increased at the outlet suggesting a leaching of Hg bound to FeS colloids that may be a dominant mechanism of Hg transport in aquifer environments. These experimental results highlight different biogeochemical mechanisms that can occur in stratified sub-surface aquifers where bacterial activities play a major role on Hg mobility and changes in speciation. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. A detailed study on the transition from the blocked to the superparamagnetic state of reduction-precipitated iron oxide nanoparticles

    International Nuclear Information System (INIS)

    Witte, K.; Bodnar, W.; Mix, T.; Schell, N.; Fulda, G.; Woodcock, T.G.; Burkel, E.

    2016-01-01

    Magnetic iron oxide nanoparticles were prepared by salt-assisted solid-state chemical precipitation method with alternating fractions of the ferric iron content. The physical properties of the precipitated nanoparticles mainly consisting of magnetite were investigated by means of transmission electron microscopy, high energy X-ray diffraction, vibrating sample magnetometry and Mössbauer spectroscopy. With particle sizes ranging from 16.3 nm to 2.1 nm, a gradual transition from the blocked state to the superparamagnetic state was observed. The transition was described as a dependence of the ferric iron content used during the precipitation. Composition, mean particle size, coercivity, saturation polarisation, as well as hyperfine interaction parameters and their evolution were studied systematically over the whole series of iron oxide nanoparticles. - Highlights: • Study of superparamagnetic transition of magnetite varying ferric iron content. • Coercivity is mainly influenced by the particle size. • Saturation polarisation influenced by the goethite content and the particle size. • Number of vacancies tend to increase with increasing ferric iron content. • Fe 3 O 4 B-sites are stronger effected by the reduction of particle size than A-sites.

  9. Iron and Non-Iron-Related Characteristics of Multiple Sclerosis and Neuromyelitis Optica Lesions at 7T MRI.

    Science.gov (United States)

    Chawla, S; Kister, I; Wuerfel, J; Brisset, J-C; Liu, S; Sinnecker, T; Dusek, P; Haacke, E M; Paul, F; Ge, Y

    2016-07-01

    patterns related to iron and noniron pathology may provide in vivo insight into the pathophysiology of lesions in MS. © 2016 by American Journal of Neuroradiology.

  10. Maternal knowledge and practices related to anaemia and iron ...

    African Journals Online (AJOL)

    African Journal of Food, Agriculture, Nutrition and Development ... prophylaxis iron supplements during pregnancy are key strategies that are used to reduce the ... important reason for non-compliance was nausea (43.6%), with 34.9% of those

  11. Bacterial disproportionation of elemental sulfur coupled to chemical reduction of iron or manganese

    DEFF Research Database (Denmark)

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

    1993-01-01

    and pyrite was observed. The transformations were accompanied by growth of slightly curved, rod-shaped bacteria. The quantification of the products revealed that S was microbially disproportionated to sulfate and sulfide, as follows: 4S + 4H(2)O --> SO(4) + 3H(2)S + 2H. Subsequent chemical reactions between...... reduction of MnO(2) to Mn. Growth of small rod-shaped bacteria was observed. When incubated without MnO(2), the culture did not grow but produced small amounts of SO(4) and H(2)S at a ratio of 1:3, indicating again a disproportionation of S. The observed microbial disproportionation of S only proceeds...... significantly in the presence of sulfide-scavenging agents such as iron and manganese compounds. The population density of bacteria capable of S disproportionation in the presence of FeOOH or MnO(2) was high, > 10 cm in coastal sediments. The metabolism offers an explanation for recent observations of anaerobic...

  12. Kinetics and mechanism of reduction of iron(iii) kojic acid complex by hydroquinone and l-cysteine

    International Nuclear Information System (INIS)

    Hussain, Z.; Perviaz, M.; Kazmi, S.A.; Johnson, A.S.; Offiong, O.E.

    2014-01-01

    The effect of pH on the kinetics of reduction of iron(III) kojic acid complex by hydroquinone (H/sub 2/Q) and L-cysteine (L-Cys) was studied in the pH range of 2.34 - 4.03 for H/sub 2/Q and 3.04 - 5.5 for L-cysteine at ionic strength of 0.5 M and at 35 degree C. The pseudo-first order rate constants for the reduction of Fe(KA)3 by L-cysteine and hydroquinone increase linearly with increasing reductant concentration, indicating first-order kinetics in reductant concentration. However, whereas the rate of reduction by H2Q increases with increasing pH, an opposite trend was observed in the case of reduction by L-cysteine. Plausible rate laws and mechanisms have been proposed in line with these observations. Activation parameters (delta H no and delta S no) were evaluated for the reduction of iron (III) kojic acid complex by cysteine and the values obtained are 35.25 kJmol-1, -141.4 JK-1mol-1 and 28.14 kJmol-1 , 161.2 JK-1mol-1 for pH 4.5 and 3.52 respectively. (author)

  13. Iron oxide reduction in methane-rich deep Baltic Sea sediments

    DEFF Research Database (Denmark)

    Egger, Matthias; Hagens, Mathilde; Sapart, Celia J.

    2017-01-01

    /L transition. Our results reveal a complex interplay between production, oxidation and transport of methane showing that besides organoclastic Fe reduction, oxidation of downward migrating methane with Fe oxides may also explain the elevated concentrations of dissolved ferrous Fe in deep Baltic Sea sediments...... profiles and numerical modeling, we propose that a potential coupling between Fe oxide reduction and methane oxidation likely affects deep Fe cycling and related biogeochemical processes, such as burial of phosphorus, in systems subject to changes in organic matter loading or bottom water salinity....

  14. Iron storage disease (hemochromatosis) and hepcidin response to iron load in two species of pteropodid fruit bats relative to the common vampire bat.

    Science.gov (United States)

    Stasiak, Iga M; Smith, Dale A; Ganz, Tomas; Crawshaw, Graham J; Hammermueller, Jutta D; Bienzle, Dorothee; Lillie, Brandon N

    2018-07-01

    Hepcidin is the key regulator of iron homeostasis in the body. Iron storage disease (hemochromatosis) is a frequent cause of liver disease and mortality in captive Egyptian fruit bats (Rousettus aegyptiacus), but reasons underlying this condition are unknown. Hereditary hemochromatosis in humans is due to deficiency of hepcidin or resistance to the action of hepcidin. Here, we investigated the role of hepcidin in iron metabolism in one species of pteropodid bat that is prone to iron storage disease [Egyptian fruit bat (with and without hemochromatosis)], one species of pteropodid bat where iron storage disease is rare [straw-colored fruit bat (Eidolon helvum)], and one species of bat with a natural diet very high in iron, in which iron storage disease is not reported [common vampire bat (Desmodus rotundus)]. Iron challenge via intramuscular injection of iron dextran resulted in significantly increased liver iron content and histologic iron scores in all three species, and increased plasma iron in Egyptian fruit bats and straw-colored fruit bats. Hepcidin mRNA expression increased in response to iron administration in healthy Egyptian fruit bats and common vampire bats, but not in straw-colored fruit bats or Egyptian fruit bats with hemochromatosis. Hepcidin gene expression significantly correlated with liver iron content in Egyptian fruit bats and common vampire bats, and with transferrin saturation and plasma ferritin concentration in Egyptian fruit bats. Induction of hepcidin gene expression in response to iron challenge is absent in straw-colored fruit bats and in Egyptian fruit bats with hemochromatosis and, relative to common vampire bats and healthy humans, is low in Egyptain fruit bats without hemochromatosis. Limited hepcidin response to iron challenge may contribute to the increased susceptibility of Egyptian fruit bats to iron storage disease.

  15. Reduction of chromate from electroplating wastewater from pH 1 to 2 using fluidized zero valent iron process

    International Nuclear Information System (INIS)

    Chen, S.-S.; Cheng, C.-Y.; Li, C.-W.; Chai, P.-H.; Chang, Y.-M.

    2007-01-01

    Fluidized zero valent iron (ZVI) process was conducted to reduce hexavalent chromium (chromate, CrO 4 2- ) to trivalent chromium (Cr 3+ ) from electroplating wastewater due to the following reasons: (1) Extremely low pH (1-2) for the electroplating wastewater favoring the ZVI reaction. (2) The ferric ion, produced from the reaction of Cr(VI) and ZVI, can act as a coagulant to assist the precipitation of Cr(OH) 3(s) to save the coagulant cost. (3) Higher ZVI utilization for fluidized process due to abrasive motion of the ZVI. For influent chromate concentration of 418 mg/L as Cr 6+ , pH 2 and ZVI dosage of 3 g (41 g/L), chromate removal was only 29% with hydraulic detention time (HRT) of 1.2 min, but was increased to 99.9% by either increasing HRT to 5.6 min or adjusting pH to 1.5. For iron species at pH 2 and HRT of 1.2 min, Fe 3+ was more thermodynamically stable since oxidizing agent chromate was present. However, if pH was adjusted to 1.5 or 1, where chromate was completely removed, high Fe 2+ but very low Fe 3+ was present. It can be explained that ZVI reacted with chromate to produce Fe 2+ first and the presence of chromate would keep converting Fe 2+ to Fe 3+ . Therefore, Fe 2+ is an indicator for complete reduction from Cr(VI) to Cr(III). X-ray diffraction (XRD) was conducted to exam the remained species at pH 2. ZVI, iron oxide and iron sulfide were observed, indicating the formation of iron oxide or iron sulfide could stop the chromate reduction reaction

  16. Iron-related gene variants and brain iron in multiple sclerosis and healthy individuals

    Directory of Open Access Journals (Sweden)

    Jesper Hagemeier

    2018-01-01

    Full Text Available Brain iron homeostasis is known to be disturbed in multiple sclerosis (MS, yet little is known about the association of common gene variants linked to iron regulation and pathological tissue changes in the brain. In this study, we investigated the association of genetic determinants linked to iron regulation with deep gray matter (GM magnetic susceptibility in both healthy controls (HC and MS patients. Four hundred (400 patients with MS and 150 age- and sex-matched HCs were enrolled and obtained 3 T MRI examination. Three (3 single nucleotide polymorphisms (SNPs associated with iron regulation were genotyped: two SNPs in the human hereditary hemochromatosis protein gene HFE: rs1800562 (C282Y mutation and rs1799945 (H63D mutation, as well as the rs1049296 SNP in the transferrin gene (C2 mutation. The effects of disease and genetic status were studied using quantitative susceptibility mapping (QSM voxel-based analysis (VBA and region-of-interest (ROI analysis of the deep GM. The general linear model framework was used to compare groups. Analyses were corrected for age and sex, and adjusted for false discovery rate. We found moderate increases in susceptibility in the right putamen of participants with the C282Y (+6.1 ppb and H63D (+6.9 ppb gene variants vs. non-carriers, as well as a decrease in thalamic susceptibility of progressive MS patients with the C282Y mutation (left: −5.3 ppb, right: −6.7 ppb, p < 0.05. Female MS patients had lower susceptibility in the caudate (−6.0 ppb and putamen (left: −3.9 ppb, right: −4.6 ppb than men, but only when they had a wild-type allele (p < 0.05. Iron-gene linked increases in putamen susceptibility (in HC and relapsing remitting MS and decreases in thalamus susceptibility (in progressive MS, coupled with apparent sex interactions, indicate that brain iron in healthy and disease states may be influenced by genetic factors.

  17. Reduction enhances yields of nitric oxide trapping by iron-diethyldithiocarbamate complex in biological systems.

    NARCIS (Netherlands)

    Vanin, A.F.; Bevers, L.M.; Mikoyan, V.D.; Poltorakov, A.P.; Kubrina, L.N.; Faassen, E. van

    2007-01-01

    The mechanism of NO trapping by iron-diethylthiocarbamate complexes was investigated in cultured cells and animal and plant tissues. Contrary to common belief, the NO radicals are trapped by iron-diethylthiocarbamates not only in ferrous but in ferric state also in the biosystems. When DETC was

  18. Multiple sclerosis deep grey matter: the relation between demyelination, neurodegeneration, inflammation and iron.

    Science.gov (United States)

    Haider, Lukas; Simeonidou, Constantina; Steinberger, Günther; Hametner, Simon; Grigoriadis, Nikolaos; Deretzi, Georgia; Kovacs, Gabor G; Kutzelnigg, Alexandra; Lassmann, Hans; Frischer, Josa M

    2014-12-01

    In multiple sclerosis (MS), diffuse degenerative processes in the deep grey matter have been associated with clinical disabilities. We performed a systematic study in MS deep grey matter with a focus on the incidence and topographical distribution of lesions in relation to white matter and cortex in a total sample of 75 MS autopsy patients and 12 controls. In addition, detailed analyses of inflammation, acute axonal injury, iron deposition and oxidative stress were performed. MS deep grey matter was affected by two different processes: the formation of focal demyelinating lesions and diffuse neurodegeneration. Deep grey matter demyelination was most prominent in the caudate nucleus and hypothalamus and could already be seen in early MS stages. Lesions developed on the background of inflammation. Deep grey matter inflammation was intermediate between low inflammatory cortical lesions and active white matter lesions. Demyelination and neurodegeneration were associated with oxidative injury. Iron was stored primarily within oligodendrocytes and myelin fibres and released upon demyelination. In addition to focal demyelinated plaques, the MS deep grey matter also showed diffuse and global neurodegeneration. This was reflected by a global reduction of neuronal density, the presence of acutely injured axons, and the accumulation of oxidised phospholipids and DNA in neurons, oligodendrocytes and axons. Neurodegeneration was associated with T cell infiltration, expression of inducible nitric oxide synthase in microglia and profound accumulation of iron. Thus, both focal lesions as well as diffuse neurodegeneration in the deep grey matter appeared to contribute to the neurological disabilities of MS patients. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  19. Fuzzy Relational Databases: Representational Issues and Reduction Using Similarity Measures.

    Science.gov (United States)

    Prade, Henri; Testemale, Claudette

    1987-01-01

    Compares and expands upon two approaches to dealing with fuzzy relational databases. The proposed similarity measure is based on a fuzzy Hausdorff distance and estimates the mismatch between two possibility distributions using a reduction process. The consequences of the reduction process on query evaluation are studied. (Author/EM)

  20. Transformation impacts of dissolved and solid phase Fe(II) on trichloroethylene (TCE) reduction in an iron-reducing bacteria (IRB) mixed column system: a mathematical model.

    Science.gov (United States)

    Bae, Yeunook; Kim, Dooil; Cho, Hyun-Hee; Singhal, Naresh; Park, Jae-Woo

    2012-12-01

    In this research, we conducted trichloroethylene (TCE) reduction in a column filled with iron and iron-reducing bacteria (IRB) and developed a mathematical model to investigate the critical reactions between active species in iron/IRB/contaminant systems. The formation of ferrous iron (Fe(II)) in this system with IRB and zero-valent iron (ZVI, Fe(0)) coated with a ferric iron (Fe(III)) crust significantly affected TCE reduction and IRB respiration in various ways. This study presents a new framework for transformation property and reducing ability of both dissolved (Fe(II)(dissolved)) and solid form ferrous iron (Fe(II)(solid)). Results showed that TCE reduction was strongly depressed by Fe(II)(solid) rather than by other inhibitors (e.g., Fe(III) and lactate), suggesting that Fe(II)(solid) might reduce IRB activation due to attachment to IRB cells. Newly exposed Fe(0) from the released Fe(II)(dissolved) was a strong contributor to TCE reduction compared to Fe(II)(solid). In addition, our research confirmed that less Fe(II)(solid) production strongly supported long-term TCE reduction because it may create an easier TCE approach to Fe(0) or increase IRB growth. Our findings will aid the understanding of the contributions of iron media (e.g., Fe(II)(solid), Fe(II)(dissolved), Fe(III), and Fe(0)) to IRB for decontamination in natural groundwater systems. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Synthesis and characterization of β-phase iron silicide nano-particles by chemical reduction

    International Nuclear Information System (INIS)

    Sen, Sabyasachi; Gogurla, Narendar; Banerji, Pallab; Guha, Prasanta K.; Pramanik, Panchanan

    2015-01-01

    Graphical abstract: - Highlights: • β-FeSi 2 nano-particle was synthesized by reducing with Mg and by diluting with MgO. • XRD profile shows the iron di-silicide phase to be semiconducting β-FeSi 2 . • HRTEM and FESEM images indicate the β-FeSi 2 average particle size to be 60–70 nm. • Absorption, reflectance and PL spectroscopy show band gap to be direct 0.87 eV. • Nano-β-FeSi 2 is p-type with hole density of 4.38 × 10 18 cm −3 and mobility 8.9 cm 2 /V s. - Abstract: Nano-particles of β-FeSi 2 have been synthesized by chemical reduction of a glassy phase of [Fe 2 O 3 , 4SiO 2 ] by Mg-metal where MgO is used as diluent to prevent the agglomeration of nano crystallites into micro-particles and also act as a negative catalyst for the formation of other phases. The sample is characterized by XRD, FESEM, HRTEM, EDX, ultra-violet-visible-infrared and PL spectroscopy and electronic properties have been investigated by Hall measurement. XRD profile shows that the synthesized powder consists of purely β-FeSi 2 semiconducting phase. The average crystallite size of β-FeSi 2 is determined to be around 65.4 nm from XRD peaks as well as from FESEM also. The optical absorption and PL spectroscopy shows that synthesized β-FeSi 2 phase is a direct band gap semiconductor with a value of 0.87 eV. Hall measurements show that β-FeSi 2 nano-particles is p-type with hole concentration of 4.38 × 10 18 cm −3 and average hole mobility of 8.9 cm 2 /V s at 300 K

  2. Reduction and immobilization of chromate in chromite ore processing residue with nanoscale zero-valent iron

    International Nuclear Information System (INIS)

    Du, Jingjing; Lu, Jinsuo; Wu, Qiong; Jing, Chuanyong

    2012-01-01

    Highlights: ► COPR remediation mechanism using nZVI was investigated. ► PHREEQC model calculation agreed well with our GANC experimental results. ► Incubation COPR and nZVI with >27% water content could reduce Cr(VI) in solids. ► Water content is the key factor to assist electron transfer between nZVI and COPR. - Abstract: Chromite ore processing residue (COPR) poses a great environmental and health risk with persistent Cr(VI) leaching. To reduce Cr(VI) and subsequently immobilize in the solid matrix, COPR was incubated with nanoscale zero-valent iron (nZVI) and the Cr(VI) speciation and leachability were studied. Multiple complementary analysis methods including leaching tests, X-ray powder diffraction, X-ray absorption near edge structure (XANES) spectroscopy, and X-ray photoelectron spectroscopy (XPS) were employed to investigate the immobilization mechanism. Geochemical PHREEQC model calculation agreed well with our acid neutralizing capacity experimental results and confirmed that when pH was lowered from 11.7 to 7.0, leachate Cr(VI) concentrations were in the range 358–445 mg L −1 which contributed over 90% of dissolved Cr from COPR. Results of alkaline digestion, XANES, and XPS demonstrated that incubation COPR with nZVI under water content higher than 27% could result in a nearly complete Cr(VI) reduction in solids and less than 0.1 mg L −1 Cr(VI) in the TCLP leachate. The results indicated that remediation approaches using nZVI to reduce Cr(VI) in COPR should be successful with sufficient water content to facilitate electron transfer from nZVI to COPR.

  3. On the Issue of Labor Relations Discontinuance by Staff Reduction

    Directory of Open Access Journals (Sweden)

    Sheveleva A. A.

    2012-11-01

    Full Text Available This article is devoted to consideration of issues related to the procedure of labor law contract termination by staff reduction. The author, analyzing the judicial practice, gives practical recommendations on the procedure of employment relationships discontinuance

  4. The reduction of U(VI) on corroded iron under anoxic conditions

    International Nuclear Information System (INIS)

    Cui, D.; Spahiu, K.

    2002-01-01

    The corrosion of iron and the interaction between corroded iron and U(VI) in anoxic conditions were investigated. The anoxic conditions were obtained by flushing an 99.97% Ar-0.03% CO 2 gas mixture through the test vessel, in which an oxygen trap and six reaction bottles containing synthetic groundwater (10 mM NaCl and 2 mM HCO 3 - .) were placed. The dark-green coloured corrosion product, formed on iron surface after three months corrosion in synthetic groundwater solutions, was identified by powder X-ray diffraction to be carbonate green rust, Fe 4 II Fe 2 III (OH) 12 CO 3 . The iron foil that reacted in a solution (10 ppm U(VI), 10 mM NaCl and 2 mM HCO 3 - ) for three months was analysed by SEM-EDS. The result shows that: (i) an uneven layer of carbonate green rust (1-5 μm thick) formed on the metallic iron; (ii) a thin (0.3 μm) uranium-rich layer deposited on top of the carbonate green rust layer; and (iii) some UO 2 crystals (3-5 μm sized) on the thin uranium layer. The experimental results proved that the U(VI) removal capacity of metal iron is not hindered by formation of a layer of carbonate green rust on the iron. Tests with cast iron and pure iron indicate that they have similar U(VI) removal capacities. At the end of experiment, U concentrations in solution approached the solubility of UO 2 (s), 10 -8 M. The stability of the carbonate green rust at the experimental conditions, pH, E h , [Fe 2+ ] and [HCO 3 - ], is discussed. (orig.)

  5. Long term energy and materials strategies for reduction of industrial CO2 emissions. A case study for the iron and steel industry

    International Nuclear Information System (INIS)

    Gielen, D.J.

    1997-01-01

    Greenhouse gas emissions emerged in the last decade as a key environmental problem on the political agenda. The most important greenhouse gas is carbon dioxide (CO 2 ). This gas results from the combustion of fossil fuels (natural gas, oil and coal). As a consequence, greenhouse gas emission reduction is closely related to energy policies. Even a stabilization of the atmospheric CO 2 concentrations at a level of 750 ppm (parts per million), more than twice the current level, implies a reduction of global emissions by 50% in the next century. The world population will simultaneously double and the capita energy consumption will increase. As a consequence, the Western industrialized countries will have to reduce their per capita emissions by more than a factor four. Such a policy goal will significantly affect the future industrial production structure. Approximately 4% of the global CO 2 emissions can be attributed to the production of iron and steel. This sector is the most important industrial source of CO 2 . The case study for the iron and steel industry will be discussed in this paper in order to illustrate the impact of significant CO 2 emission mitigation on the industry. The goal is to show the consequences of CO 2 policies for R and D planning and investment decisions. The notion that the iron and steel industry will be affected by CO 2 policies is not new; a number of studies have addressed this issue before. These studies have compared steel production technologies and emission reduction options within the iron and steel production sector. In this paper, the emission reduction in the iron and steel industry is analyzed within the framework of the changing (inter-)national energy and materials system configuration. This includes all production, conversion and consumption processes. The impact of CO 2 policies on the optimal choice of steel production technologies and on the competitiveness of steel compared to other materials will be discussed. This paper

  6. Relation of iron stores to oxidative stress in type 2 diabetes | Kundu ...

    African Journals Online (AJOL)

    Relation of iron stores to oxidative stress in type 2 diabetes. ... patients who attended the outpatient and inpatient departments of Medical College, Kolkata. ... levels to MDA levels in the diabetic cases of longer duration of more than 10 years.

  7. Iron (II) tetrakis(diaquaplatinum) octacarboxyphthalocyanine supported on multi-walled carbon nanotubes as effective electrocatalyst for oxygen reduction reaction in alkaline medium

    CSIR Research Space (South Africa)

    Mamuru, SA

    2010-11-01

    Full Text Available Oxygen reduction reaction (ORR) in alkaline medium at iron (II) tetrakis (diaquaplatinum) octacarboxyphthalocyanine (PtFeOCPc) catalyst supported on multi-walled carbon nanotubes (MWCNTs) has been described. The ORR followed the direct 4-electron...

  8. Oxygen reduction reaction at MWCNT-modified nanoscale iron(II) tetrasulfophthalocyanine: remarkable performance over platinum and tolerance toward methanol in alkaline medium

    CSIR Research Space (South Africa)

    Fashedemi, OO

    2015-04-01

    Full Text Available A nanoscale iron(II) tetrasulfophthalocyanine (nanoFeTSPc) catalyst obtained by co-ordinating with hexadecyltrimethylammonium bromide and subsequently anchored onto multi-walled carbon nanotubes (MWCNTs) for oxygen reduction reaction (ORR) has been...

  9. Reductive dehalogenation by layered iron(II)-iron(III) hydroxides and related iron(II) containing solids

    DEFF Research Database (Denmark)

    Yin, Weizhao

    In the present PhD project, novel synthesis and modifications of layered Fe(II)-Fe(III) hydroxides (green rusts, GRs) were investigated with focus on improved dehalogenation of carbon tetrachloride by using modified green rusts and/or altered reaction conditions. The Ph.D. project has comprised: 1...... sulphate green rust formation by aerial oxidation of FeII or co-precipitation by adding Fe(III) salt to Fe(II). In comparison with traditional green rust synthesis, pure GRs were synthesized in minutes. 2. Enhanced dehalogenation of CT by GR in presence of selected amino acids. In presence of glycine......, chloroform (CF) formation is effectively suppressed: less than 10% of CT is transformed to CF, and more than 90% of dehalogenation products are found to be formic acid and carbon monoxide in presence of 60 mM glycine; while a 80% of CF recovery was obtained without amino acids addition. 3. A “switch...

  10. Stable Fe isotope fractionation during anaerobic microbial dissimilatory iron reduction at low pH

    Science.gov (United States)

    Chanda, P.; Amenabar, M. J.; Boyd, E. S.; Beard, B. L.; Johnson, C.

    2017-12-01

    In low-temperature anaerobic environments microbial dissimilatory iron reduction (DIR) plays an important role in Fe cycling. At neutral pH, sorption of aqueous Fe(II) (Fe(II)aq, produced by DIR) catalyzes isotopic exchange between Fe(II) and solid Fe(III), producing 56Fe/54Fe fractionations on the order of 3‰ during DIR[1,2,3]. At low pH, however, the absence of sorbed Fe(II) produces only limited abiologic isotopic exchange[4]. Here we investigated the scope of isotopic exchange between Fe(II)aq and ferric (hydr)oxides (ferrihydrite and goethite) and the associated stable Fe isotope fractionation during DIR by Acidianus strain DS80 at pH 3.0 and 80°C[5]. Over 19 days, 13% reduction of both minerals via microbial DIR was observed. The δ56Fe values of the fluid varied from -2.31 to -1.63‰ (ferrihydrite) and -0.45 to 0.02‰ (goethite). Partial leaching of bulk solid from each reactor with dilute HCl showed no sorption of Fe(II), and the surface layers of the solids were composed of Fe(III) with high δ56Fe values (ferrihydrite: 0.20 to 0.48‰ and goethite: 1.20 to 1.30‰). These results contrast with the lack of Fe isotope exchange in abiologic low-pH systems and indicate a key role for biology in catalyzing Fe isotope exchange between Fe(II)aq and Fe(III) solids, despite the absence of sorbed Fe(II). The estimated fractionation factor (ΔFeFe(III) -Fe(II)aq 2.6‰) from leaching of ferrihydrite is similar to the abiologic equilibrium fractionation factor ( 3.0‰)[3]. The fractionation factor (ΔFeFe(III) -Fe(II)aq 2.0‰) for goethite is higher than the abiologic fractionation factor ( 1.05‰)[2], but is consistent with the previously proposed "distorted surface layer" of goethite produced during the exchange with Fe(II)aq at neutral pH[1]. This study indicates that significant variations in Fe isotope compositions may be produced in low-pH environments where biological cycling of Fe occurs, in contrast to the expected lack of isotopic fractionation in

  11. Plasma Deposited Thin Iron Oxide Films as Electrocatalyst for Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Lukasz JOZWIAK

    2017-02-01

    Full Text Available The possibility of using plasma deposited thin films of iron oxides as electrocatalyst for oxygen reduction reaction (ORR in proton exchange membrane fuel cells (PEMFC was examined. Results of energy-dispersive X-ray spectroscopy (EDX and X-ray photoelectron spectroscopy (XPS analysis indicated that the plasma deposit consisted mainly of FeOX structures with the X parameter close to 1.5. For as deposited material iron atoms are almost exclusively in the Fe3+ oxidation state without annealing in oxygen containing atmosphere. However, the annealing procedure can be used to remove the remains of carbon deposit from surface. The single cell test (SCT was performed to determine the suitability of the produced material for ORR. Preliminary results showed that power density of 0.23 mW/cm2 could be reached in the tested cell.DOI: http://dx.doi.org/10.5755/j01.ms.23.1.14406

  12. Acidithrix ferrooxidans gen. nov., sp. nov.; a filamentous and obligately heterotrophic, acidophilic member of the Actinobacteria that catalyzes dissimilatory oxido-reduction of iron.

    Science.gov (United States)

    Jones, Rose M; Johnson, D Barrie

    2015-01-01

    A novel acidophilic member of the phylum Actinobacteria was isolated from an acidic stream draining an abandoned copper mine in north Wales. The isolate (PY-F3) was demonstrated to be a heterotroph that catalyzed the oxidation of ferrous iron (but not of sulfur or hydrogen) under aerobic conditions, and the reduction of ferric iron under micro-aerobic and anaerobic conditions. PY-F3 formed long entangled filaments of cells (>50 μm long) during active growth phases, though these degenerated into smaller fragments and single cells in late stationary phase. Although isolate PY-F3 was not observed to grow below pH 2.0 and 10 °C, harvested biomass was found to oxidize ferrous iron at relatively fast rates at pH 1.5 and 5 °C. Phylogenetic analysis, based on comparisons of 16S rRNA gene sequences, showed that isolate PY-F3 has 91-93% gene similarity to those of the four classified genera and species of acidophilic Actinobacteria, and therefore is a representative of a novel genus. The binomial Acidithrix ferrooxidans is proposed for this new species, with PY-F3 as the designated type strain (=DSM 28176(T), =JCM 19728(T)). Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  13. Reductive Degradation of Perfluorinated Compounds in Water using Mg-aminoclay coated Nanoscale Zero Valent Iron

    OpenAIRE

    Arvaniti, Olga S.; Hwang, Yuhoon; Andersen, Henrik Rasmus; Stasinakis, Athanasios S.; Thomaidis , Nikolaos S.; Aloupi, Maria

    2015-01-01

    Perfluorinated Compounds (PFCs) are extremely persistent micropollutants that are detected worldwide. We studied the removal of PFCs (perfluorooctanoic acid; PFOA, perfluorononanoic acid; PFNA, perfluorodecanoic acid; PFDA and perfluorooctane sulfonate; PFOS) from water by different types of nanoscale zero-valent iron (nZVI). Batch experiments showed that an iron dose of 1 g•L-1 in the form of Mg-aminoclay (MgAC) coated nZVI, at an initial pH of 3.0 effectively removed 38 % to 96 % of individ...

  14. Influence of Carbon Sources and Electron Shuttles on Ferric Iron Reduction by Cellulomonas sp. Strain ES6

    Energy Technology Data Exchange (ETDEWEB)

    Erin K. Field; Robin Gerlach; Sridhar Viamajala; Laura K. Jennings; Alfred B. Cunningham; Brent M. Peyton; William A. Apel

    2011-09-01

    The reduction of hexavalent chromium, Cr(VI), to trivalent chromium, Cr(III), can be an important aspect of remediation processes at Department of Energy (DOE) and other contaminated sites. Cellulomonas species are found at several Cr(VI) contaminated and uncontaminated locations at the DOE site in Hanford, Washington. Members of this genus have demonstrated the ability to effectively reduce Cr(VI) to Cr(III) fermentatively and therefore play a potential role in hexavalent chromium remediation at this site. Batch studies were conducted with Cellulomonas sp. strain ES6 to assess the influence of various carbon sources, iron minerals, and electron shuttling compounds on Cr(VI) reduction. These chemical species are likely to be present in these terrestrial environments during in situ bioremediation. Results indicated that there were a number of interactions between these compounds that influenced Cr(VI) reduction rates. The type of carbon source as well as the type of electron shuttle present influenced Cr(VI) reduction rates. When an electron shuttle, such as anthraquinone-2,6-disulfonate (AQDS), was present in the system, reduction rates increased significantly. Biologically reduced AQDS (AHDS) reduced Cr(VI) almost instantaneously. The presence of iron minerals and their concentrations did not significantly influence Cr(VI) reduction rates. However, strain ES6 or AQDS could directly reduce surface-associated Fe(III) to Fe(II) which was capable of reducing Cr(VI) at a near instantaneous rate. These results suggest the rate limiting step in these systems is the transfer of electrons from strain ES6 to the intermediate or terminal electron acceptor whether that is Cr(VI), Fe(III), or AQDS.

  15. Moessbauer spectroscopic evidence for iron(III) complexation and reduction in acidic aqueous solutions of indole-3-butyric acid

    International Nuclear Information System (INIS)

    Kovacs, K.; Kuzmann, E.; Vertes, A.; Kamnev, A.A.; Shchelochkov, A.G.; Medzihradszky-Schweiger, H.; Mink, J.; Hungarian Academy of Sciences, Budapest

    2004-01-01

    Moessbauer spectroscopic studies were carried out in acidic (pH 2.3) 57 Fe III nitrate containing aqueous solutions of indole-3-butyric acid (IBA), rapidly frozen in liquid nitrogen at various periods of time after mixing the reagents. The data obtained show that in solution in the presence of IBA, iron(III) forms a complex with a dimeric structure characterised by a quadrupole doublet, whereas without IBA under similar conditions iron(III) exhibits a broad spectral feature due to a slow paramagnetic spin relaxation which, at liquid nitrogen temperature, results in a large anomalous line broadening (or, at T = 4.2 K, in a hyperfine magnetic splitting). The spectra of 57 Fe III +IBA solutions, kept at ambient temperature under aerobic conditions for increasing periods of time before freezing, contained a gradually increasing contribution of a component with a higher quadrupole splitting. The Moessbauer parameters for that component are typical for iron(II) aquo complexes, thus showing that under these conditions gradual reduction of iron(III) occurs, so that the majority (85%) of dissolved iron(III) is reduced within 2 days. The Moessbauer parameters for the iron(III)-IBA complex in aqueous solution and in the solid state (separated from the solution by filtration) were found to be similar, which may indicate that the dissolved and solid complexes have the same composition and/or iron(III) coordination environment. For the solid complex, the data of elemental analysis suggest the following composition of the dimer: [L 2 Fe-(OH) 2 -FeL 2 ] (where L is indole-3-butyrate). This structure is also in agreement with the data of infrared spectroscopic study of the complex reported earlier, with the side-chain carboxylic group in indole-3-butyrate as a bidentate ligand. The Moessbauer parameters for the solid 57 Fe III -IBA complex at T = 80 K and its acetone solution rapidly frozen in liquid nitrogen were virtually identical, which indicates that the complex retains its

  16. Investigation of iron(III) reduction and trace metal interferences in the determination of dissolved iron in seawater using flow injection with luminol chemiluminescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Ussher, Simon J. [School of Earth, Ocean and Environmental Sciences (SEOES), University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Milne, Angela [School of Earth, Ocean and Environmental Sciences (SEOES), University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Department of Oceanography, Florida State University, Tallahassee, FL 32306-4320 (United States); Landing, William M. [Department of Oceanography, Florida State University, Tallahassee, FL 32306-4320 (United States); Attiq-ur-Rehman, Kakar [Department of Chemistry, University of Balochistan, Quetta (Pakistan); Seguret, Marie J.M.; Holland, Toby [School of Earth, Ocean and Environmental Sciences (SEOES), University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Achterberg, Eric P. [National Oceanography Centre, University of Southampton, European Way, Southampton SO14 3ZH (United Kingdom); Nabi, Abdul [Department of Chemistry, University of Balochistan, Quetta (Pakistan); Worsfold, Paul J., E-mail: pworsfold@plymouth.ac.uk [School of Earth, Ocean and Environmental Sciences (SEOES), University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)

    2009-10-12

    A detailed investigation into the performance of two flow injection-chemiluminescence (FI-CL) manifolds (with and without a preconcentration column) for the determination of sub-nanomolar dissolved iron (Fe(II) + Fe(III)), following the reduction of Fe(III) by sulphite, in seawater is described. Kinetic experiments were conducted to examine the efficiency of reduction of inorganic Fe(III) with sulphite under different conditions and a rigorous study of the potential interference caused by other transition metals present in seawater was conducted. Using 100 {mu}M concentrations of sulphite a reduction time of 4 h was sufficient to quantitatively reduce Fe(III) in seawater. Under optimal conditions, cobalt(II) and vanadium(IV)/(III) were the major positive interferences and strategies for their removal are reported. Specifically, cobalt(II) was masked by the addition of dimethylglyoxime to the luminol solution and vanadium(IV) was removed by passing the sample through an 8-hydroxyquinoline column in a low pH carrier stream. Manganese(II) also interfered by suppression of the CL response but this was not significant at typical open ocean concentrations.

  17. Recovery of Work-Related Stress: Complaint Reduction and Work-Resumption are Relatively Independent Processes

    NARCIS (Netherlands)

    Vente, W. de; Kamphuis, J.H.; Blonk, R.W.; Emmelkamp, P.M.

    2015-01-01

    Purpose The process of recovery from work-related stress, consisting of complaint reduction and work-resumption, is not yet fully understood. The aim of this study was to investigate predictors of complaint reduction and work-resumption, as well as testing complaint reduction as a mediator in the

  18. Recovery of work-related stress: Complaint reduction and work-resumption are relatively independent processes

    NARCIS (Netherlands)

    de Vente, W.; Kamphuis, J.H.; Blonk, R.W.B.; Emmelkamp, P.M.G.

    2015-01-01

    Purpose: The process of recovery from work-related stress, consisting of complaint reduction and work-resumption, is not yet fully understood. The aim of this study was to investigate predictors of complaint reduction and work-resumption, as well as testing complaint reduction as a mediator in the

  19. Reduction Pathways of Cyclooctatetraene Iron Tricarbonyl as Examined Using Infrared Spectroelectrochemistry.

    Science.gov (United States)

    1987-09-25

    173/175/179 potentiostat system was used for voltammetric measurements and thin-layer electrolyses . Cyclooctatetraene iron tricarbonyl was synthesised...the subsequent addftion of water . 3 The infrared spectrum for this species contains similar features to those, in Fig. 3B, including a band around 1670

  20. Electrochemical probing into the active sites of graphitic-layer encapsulated iron oxygen reduction reaction electrocatalysts

    DEFF Research Database (Denmark)

    Zhong, Lijie; Jensen, Jens Oluf; Cleemann, Lars Nilausen

    2018-01-01

    is still unclear compared with the well-recognized surface coordinated FeNx/C structure. Using the strong complexing effect of the iron component with anions, cyanide (CN−) in alkaline and thiocyanate (SCN−) in acidic media, the metal containing active sites are electrochemically probed. Three...

  1. Toxicity of xenobiotics during sulfate, iron, and nitrate reduction in primary sewage sludge suspensions

    DEFF Research Database (Denmark)

    Elsgaard, Lars

    2010-01-01

    The effect and persistence of six organic xenobiotics was tested under sulfate-, iron-, and nitrate-reducing conditions in primary sewage sludge suspensions. The xenobiotics tested were acenaphthene, phenanthrene, di(2-ethylhexyl)phthalate (DEHP), 4-nonylphenol (4-NP), linear alkylbenzene sulfonate...

  2. Variation of iron redox kinetics and its relation with molecular composition of standard humic substances at circumneutral pH.

    Science.gov (United States)

    Lee, Ying Ping; Fujii, Manabu; Kikuchi, Tetsuro; Terao, Koumei; Yoshimura, Chihiro

    2017-01-01

    Oxidation and reduction kinetics of iron (Fe) and proportion of steady-state Fe(II) concentration relative to total dissolved Fe (steady-state Fe(II) fraction) were investigated in the presence of various types of standard humic substances (HS) with particular emphasis on the photochemical and thermal reduction of Fe(III) and oxidation of Fe(II) by dissolved oxygen (O2) and hydrogen peroxide (H2O2) at circumneutral pH (pH 7-8). Rates of Fe(III) reduction were spectrophotometrically determined by a ferrozine method under the simulated sunlight and dark conditions, whereas rates of Fe(II) oxidation were examined in air-saturated solution using luminol chemiluminescence technique. The reduction and oxidation rate constants were determined to substantially vary depending on the type of HS. For example, the first-order rate constants varied by up to 10-fold for photochemical reduction and 7-fold for thermal reduction. The degree of variation in Fe(II) oxidation was larger for the H2O2-mediated reaction compared to the O2-mediated reaction (e.g., 15- and 3-fold changes for the former and latter reactions, respectively, at pH 8). The steady-state Fe(II) fraction under the simulated sunlight indicated that the Fe(II) fraction varies by up to 12-fold. The correlation analysis indicated that variation of Fe(II) oxidation is significantly associated with aliphatic content of HS, suggesting that Fe(II) complexation by aliphatic components accelerates Fe(II) oxidation. The reduction rate constant and steady-state Fe(II) fractions in the presence of sunlight had relatively strong positive relations with free radical content of HS, possibly due to the reductive property of radical semiquinone in HS. Overall, the findings in this study indicated that the Fe reduction and oxidation kinetics and resultant Fe(II) formation are substantially influenced by chemical properties of HS.

  3. Absolute risk, absolute risk reduction and relative risk

    Directory of Open Access Journals (Sweden)

    Jose Andres Calvache

    2012-12-01

    Full Text Available This article illustrates the epidemiological concepts of absolute risk, absolute risk reduction and relative risk through a clinical example. In addition, it emphasizes the usefulness of these concepts in clinical practice, clinical research and health decision-making process.

  4. Expression of Iron-Related Proteins Differentiate Non-Cancerous and Cancerous Breast Tumors

    Directory of Open Access Journals (Sweden)

    Sara Pizzamiglio

    2017-02-01

    Full Text Available We have previously reported hepcidin and ferritin increases in the plasma of breast cancer patients, but not in patients with benign breast disease. We hypothesized that these differences in systemic iron homeostasis may reflect alterations in different iron-related proteins also play a key biochemical and regulatory role in breast cancer. Thus, here we explored the expression of a bundle of molecules involved in both iron homeostasis and tumorigenesis in tissue samples. Enzyme-linked immunosorbent assay (ELISA or reverse-phase protein array (RPPA, were used to measure the expression of 20 proteins linked to iron processes in 24 non-cancerous, and 56 cancerous, breast tumors. We found that cancerous tissues had higher level of hepcidin than benign lesions (p = 0.012. The univariate analysis of RPPA data highlighted the following seven proteins differentially expressed between non-cancerous and cancerous breast tissue: signal transducer and transcriptional activator 5 (STAT5, signal transducer and activator of transcription 3 (STAT3, bone morphogenetic protein 6 (BMP6, cluster of differentiation 74 (CD74, transferrin receptor (TFRC, inhibin alpha (INHA, and STAT5_pY694. These findings were confirmed for STAT5, STAT3, BMP6, CD74 and INHA when adjusting for age. The multivariate statistical analysis indicated an iron-related 10-protein panel effective in separating non-cancerous from cancerous lesions including STAT5, STAT5_pY694, myeloid differentiation factor 88 (MYD88, CD74, iron exporter ferroportin (FPN, high mobility group box 1 (HMGB1, STAT3_pS727, TFRC, ferritin heavy chain (FTH, and ferritin light chain (FTL. Our results showed an association between some iron-related proteins and the type of tumor tissue, which may provide insight in strategies for using iron chelators to treat breast cancer.

  5. DOC-dynamics in a small headwater catchment as driven by redox fluctuations and hydrological flow paths – are DOC exports mediated by iron reduction/oxidation cycles?

    Directory of Open Access Journals (Sweden)

    K.-H. Knorr

    2013-02-01

    Full Text Available Dissolved organic carbon (DOC exports from many catchments in Europe and North-America are steadily increasing. Several studies have sought to explain this observation. As possible causes, a decrease in acid rain or sulfate deposition, concomitant reductions in ionic strength and increasing temperatures were identified. DOC often originates from riparian wetlands; but here, despite higher DOC concentrations, ionic strength in pore waters usually exceeds that in surface waters. In the catchment under study, DOC concentrations were synchronous with dissolved iron concentrations in pore and stream water. This study aims at testing the hypothesis that DOC exports are mediated by iron reduction/oxidation cycles. Following the observed hydrographs, δ18O of water and DOC fluorescence, the wetlands were identified as the main source of DOC. Antecedent biogeochemical conditions, i.e., water table levels in the wetlands, influenced the discharge patterns of nitrate, iron and DOC during an event. The correlation of DOC with pH was positive in pore waters, but negative in surface waters; it was negative for DOC with sulfate in pore waters, but only weak in surface waters. Though, the positive correlation of DOC with iron was universal for pore and surface water. The decline of DOC and iron concentrations in transition from anoxic wetland pore water to oxic stream water suggests a flocculation of DOC with oxidising iron, leading to a drop in pH in the stream during high DOC fluxes. The pore water did not per se differ in pH. There is, thus, a need to consider processes more thoroughly of DOC mobilisation in wetlands when interpreting DOC exports from catchments. The coupling of DOC with iron fluxes suggested that increased DOC exports could at least, in part, be caused by increasing activities in iron reduction, possibly due to increases in temperature, increasing wetness of riparian wetlands, or by a shift from sulfate dominated to iron

  6. Bromate Reduction by Iron(II during Managed Aquifer Recharge: A Laboratory-Scale Study

    Directory of Open Access Journals (Sweden)

    Feifei Wang

    2018-03-01

    Full Text Available The removal of bromate (BrO3− as a byproduct of ozonation in subsequent managed aquifer recharge (MAR systems has so far gained little attention. This preliminary study with anoxic batch experiments was executed to explore the feasibility of chemical BrO3− reduction in Fe-reducing zones of MAR systems and to estimate potential inhibition by NO3−. Results show that the reaction rate was affected by initial Fe2+/BrO3− ratios and by pH. The pH dropped significantly due to the hydrolysis of Fe3+ to hydrous ferric oxide (HFO flocs. These HFO flocs were found to adsorb Fe2+, especially at high Fe2+/BrO3− ratios, whereas at low Fe2+/BrO3− ratios, the mass sum loss of BrO3− and Br− indicated intermediate species formation. Under MAR conditions with relatively low BrO3− and Fe2+ concentrations, BrO3− can be reduced by naturally occurring Fe2+, as the extensive retention time in MAR systems will compensate for the slow reaction kinetics of low BrO3− and Fe2+ concentrations. Under specific flow conditions, Fe2+ and NO3− may co-occur during MAR, but NO3− hardly competes with BrO3−, since Fe2+ prefers BrO3− over NO3−. However, it was found that when NO3− concentration exceeds BrO3− concentration by multiple orders of magnitude, NO3− may slightly inhibit BrO3− reduction by Fe2+.

  7. Lactate Oxidation Coupled to Iron or Electrode Reduction by Geobacter sulfurreducens PCA

    KAUST Repository

    Call, D. F.

    2011-10-14

    Geobacter sulfurreducens PCA completely oxidized lactate and reduced iron or an electrode, producing pyruvate and acetate intermediates. Compared to the current produced by Shewanella oneidensis MR-1, G. sulfurreducens PCA produced 10-times-higher current levels in lactate-fed microbial electrolysis cells. The kinetic and comparative analyses reported here suggest a prominent role of G. sulfurreducens strains in metaland electrode-reducing communities supplied with lactate. © 2011, American Society for Microbiology.

  8. Lactate Oxidation Coupled to Iron or Electrode Reduction by Geobacter sulfurreducens PCA

    KAUST Repository

    Call, D. F.; Logan, B. E.

    2011-01-01

    Geobacter sulfurreducens PCA completely oxidized lactate and reduced iron or an electrode, producing pyruvate and acetate intermediates. Compared to the current produced by Shewanella oneidensis MR-1, G. sulfurreducens PCA produced 10-times-higher current levels in lactate-fed microbial electrolysis cells. The kinetic and comparative analyses reported here suggest a prominent role of G. sulfurreducens strains in metaland electrode-reducing communities supplied with lactate. © 2011, American Society for Microbiology.

  9. Graphic-analytical determination of statics of reduction reextraction of plutonium using iron(2) as a reducing agent

    International Nuclear Information System (INIS)

    Pochinajlo, A.

    1977-01-01

    The grafic technological scheme of reduction reextraction of plutonium has been designed and the experiments on the laboratory 16-staged extractor of a mixer-settler type have been carried. From the concentration profiles found for a steady stage the content of plutonium(4) and plutonium(3) in organic and water phases in every stage is calculated. Then using the equations of material balance and extraction equilibrium a kinetic formula describing the reduction of plutonium(4) by iron(2f.) in a separate stage is deduced. Since the kinetic parameter A has been found to be close for all the staqes the analytical expression has been obtained with the help of which it is possible to determine a priori the plutonium(4) concentration profile in a reextraction part of the extractor for the given technological process conditions characterized by the defenite A. The plutonium(4) concentration profiles for the organic phase with different values A are presented

  10. Industrial study of iron oxide reduction by injection of carbon particles into the electric arc furnace

    International Nuclear Information System (INIS)

    Conejo, A. N.; Torres, R.; Cuellar, E.

    1999-01-01

    An industrial study was conducted in electric arc furnaces (EAF) employing 100% direct reduced iron to evaluate the oxidation level of the slag-metal system. Energy consumption is decreased by injecting gaseous oxygen, however, slag oxidation also increases. In order to reduce the extent of oxidation while keeping a high volume of the oxygen injected , it is required: a) to optimize the carbon injection practice, b) to increase the carbon concentration of sponge iron, c) to operate with soluble carbon in both the metal and the slag beyond a critical level and d) to employ a low temperature profile, on average 1,650 degree centigrade. A method to define the proper amount of carbon in sponge iron which considers their metallization as well as the amount of oxygen injected is proposed. The position of the lance is critical in order to optimize the practice of carbon injection and assure a better residence time of the carbon particles within the furnace. (Author) 23 refs

  11. Experimental study and modelling of iron ore reduction by hydrogen; Etude experimentale et modelisation de la reduction du minerai de fer par l'hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, D

    2008-01-15

    In an effort to find new ways to drastically reduce the CO{sub 2} emissions from the steel industry (ULCOS project), the reduction of iron ore by pure hydrogen in a shaft furnace was investigated. The work consisted of literature, experimental, and modelling studies. The chemical reaction and its kinetics were analysed on the basis of thermogravimetric experiments and physicochemical characterizations of partially reduced samples. A specific kinetic model was designed, which simulates the successive reactions, the different steps of mass transport, and possible iron sintering, at the particle scale. Finally, a 2-dimensional numerical model of a shaft furnace was developed. It depicts the variation of the solid and gas temperatures and compositions throughout the reactor. One original feature of the model is using the law of additive characteristic times for calculating the reaction rates. This allowed us to handle both the particle and the reactor scale, while keeping reasonable calculation time. From the simulation results, the influence of the process parameters was assessed. Optimal operating conditions were concluded, which reveal the efficiency of the hydrogen process. (author)

  12. Recovery of Work-Related Stress: Complaint Reduction and Work-Resumption are Relatively Independent Processes.

    Science.gov (United States)

    de Vente, Wieke; Kamphuis, Jan Henk; Blonk, Roland W B; Emmelkamp, Paul M G

    2015-09-01

    The process of recovery from work-related stress, consisting of complaint reduction and work-resumption, is not yet fully understood. The aim of this study was to investigate predictors of complaint reduction and work-resumption, as well as testing complaint reduction as a mediator in the association between predictors and work-resumption. Seventy-one patients on sickness-leave because of work-related stress complaints were followed over a period of 13 months. Predictors comprised personal (demographics, coping, cognitions), work-related (job-characteristics, social support), and illness-related (complaint duration, absence duration) variables. Dependent variables were distress complaints, burnout complaints, and work-resumption. Complaints reduced considerably over time to borderline clinical levels and work-resumption increased to 68% at 13 months. Predictors of stronger reduction of distress complaints were male gender, less working hours, less decision authority, more co-worker support, and shorter absence duration. Predictors of stronger reduction of burnout complaints were male gender, lower age, high education, less avoidant coping, less decision authority, more job security, and more co-worker support. Predictors of work-resumption were lower age and stronger reduction of burnout complaints. No indication for a mediating role of burnout complaints between the predictor age and work-resumption was found. Complaint reduction and work-resumption are relatively independent processes. Symptom reduction is influenced by individual and work-related characteristics, which holds promise for a multidisciplinary treatment approach for work-related stress.

  13. Vivianite Precipitation and Phosphate Sorption following Iron Reduction in Anoxic Soils

    DEFF Research Database (Denmark)

    Heiberg, Lisa; Bender Koch, Christian; Kjærgaard, Charlotte

    2012-01-01

    , the Fe(II) production reached its maximum and 34% of the citrate–bicarbonate–dithionite extractable Fe (FeCBD) was reduced to Fe(II) in the sandy soil. The peat soil showed a much faster reduction of Fe(III) and the maximum reduction of 89% of FeCBD was reached after 200 d. Neoformation...

  14. Blood transfusion reduction with intravenous iron in gynecologic cancer patients receiving chemotherapy.

    Science.gov (United States)

    Dangsuwan, Penkae; Manchana, Tarinee

    2010-03-01

    To compare the incidence of repeated red blood cell (RBC) transfusion in anemic gynecologic cancer patients receiving platinum-based chemotherapy comparing intravenous and oral iron. Forty-four anemic gynecologic cancer patients (hemoglobin level below 10 mg/dl) who required RBC transfusion were stratified and randomized according to baseline hemoglobin levels and chemotherapy regimen. Study group received 200 mg of intravenous iron sucrose and control group received oral ferrous sulphate 600 mg/day. RBC transfusion requirement in the consecutive cycle of chemotherapy was the primary outcome. Quality of life was evaluated by validated Thai version of the Functional Assessment of Cancer Therapy-Anemia (FACT-An). In a total of the 44 patients, there were 22 patients in each group. Five patients (22.7%) in the study group and 14 patients (63.6%) in the control group required RBC transfusion in consecutive cycle of chemotherapy (p=0.01). No significant difference in baseline hemoglobin and hematocrit levels was demonstrated in both groups. Significantly higher mean hemoglobin and hematocrit levels after treatment were reported in the study group (10.0+/-0.8 g/dl and 30.5+/-2.4%) than the control group (9.5+/-0.9 g/dl and 28.4+/-2.7%). No significant change of total FACT-An scores was noted between before and after treatment in both groups. No serious adverse events were reported and there was no significant difference among adverse events between both groups. Intravenous iron is an alternative treatment for anemic gynecologic cancer patients receiving platinum-based chemotherapy and reduces the incidence of RBC transfusion without serious adverse events.

  15. The relative validity and reproducibility of an iron food frequency questionnaire for identifying iron-related dietary patterns in young women.

    Science.gov (United States)

    Beck, Kathryn L; Kruger, Rozanne; Conlon, Cathryn A; Heath, Anne-Louise M; Coad, Jane; Matthys, Christophe; Jones, Beatrix; Stonehouse, Welma

    2012-08-01

    Using food frequency data to identify dietary patterns is a newly emerging approach to assessing the relationship between dietary intake and iron status. Food frequency questionnaires should be assessed for validity and reproducibility before use. We aimed to investigate the relative validity and reproducibility of an iron food frequency questionnaire (FeFFQ) specifically designed to identify iron-related dietary patterns. Participants completed the FeFFQ at baseline (FeFFQ1) and 1 month later (FeFFQ2) to assess reproducibility. A 4-day weighed diet record (4DDR) was completed between these assessments to determine validity. Foods appearing in the 4DDR were classified into the same 144 food groupings as the FeFFQ. Factor analysis was used to determine dietary patterns from FeFFQ1, FeFFQ2, and the 4DDR. A convenience sample of women (n=115) aged 18 to 44 years living in Auckland, New Zealand, during 2009. Agreement between diet pattern scores was compared using correlation coefficients, Bland-Altman analysis, cross-classification, and the weighted κ statistic. A "healthy" and a "sandwich and drinks" dietary pattern were identified from all three dietary assessments. Correlation coefficients between FeFFQ1 and the 4DDR diet pattern scores (validity) were 0.34 for the healthy, and 0.62 for the sandwich and drinks pattern (both Ps50% of participants into the correct tertile and <10% into the opposite tertile for both the healthy and sandwich and drinks diet pattern scores when compared with the 4DDR and FeFFQ2. The FeFFQ appears to be a reproducible and relatively valid method for identifying dietary patterns, and could be used to investigate the relationship between dietary patterns and iron status. Copyright © 2012 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  16. Graphitic Layer Encapsulated Iron Based Non‐precious Catalysts for the Oxygen Reduction Reaction

    DEFF Research Database (Denmark)

    Zhong, Lijie

    consisting of uniform metallic nanoparticles encapsulated in graphitic layers. The thesis work is conducted aiming at three major objectives: further optimization of the pyrolysis to achieve improved performance of catalysts, investigation of the complex Fe-containing components, and exploration...... of the nitrogen functionalities. Two anions in the electrolyte are used to probe the iron containing active sites towards the ORR, cyanide (CN-) in alkaline and thiocyanate (SCN-) in acidic medium, which seem supporting the above conclusions. These findings provide new insights to the encapsulation structure...

  17. Oxygen reduction reaction properties of nitrogen-incorporated nanographenes synthesized using in-liquid plasma from mixture of ethanol and iron phthalocyanine

    Science.gov (United States)

    Amano, Tomoki; Kondo, Hiroki; Takeda, Keigo; Ishikawa, Kenji; Hiramatsu, Mineo; Sekine, Makoto; Hori, Masaru

    2018-04-01

    Nanographenes were synthesized using in-liquid plasma from a mixture of iron phthalocyanine and ethanol. In a previous study, micrometer-scale flakes with nitrogen incorporation were obtained. A nonprecious metal catalytic activity was observed with 3.13 electrons in an oxygen reduction reaction under an acidic solute condition. Large-surface-area, high-graphene-crystallinity, and iron-carbon-bonding sites were found owing to a high catalytic activity in Fe-N/nanographene.

  18. Investigation on Abnormal Iron Metabolism and Related Inflammation in Parkinson Disease Patients with Probable RBD

    Science.gov (United States)

    Hu, Yang; Yu, Shu-Yang; Zuo, Li-Jun; Piao, Ying-Shan; Cao, Chen-Jie; Wang, Fang; Chen, Ze-Jie; Du, Yang; Lian, Teng-Hong; Liu, Gai-Fen; Wang, Ya-Jie; Chan, Piu; Chen, Sheng-Di; Wang, Xiao-Min; Zhang, Wei

    2015-01-01

    Objective To investigate potential mechanisms involving abnormal iron metabolism and related inflammation in Parkinson disease (PD) patients with probable rapid eye movement sleep behavior disorder (PRBD). Methods Total 210 PD patients and 31 controls were consecutively recruited. PD patients were evaluated by RBD Screening Questionnaire (RBDSQ) and classified into PRBD and probable no RBD (NPRBD) groups. Demographics information were recorded and clinical symptoms were evaluated by series of rating scales. Levels of iron and related proteins and inflammatory factors in cerebrospinal fluid (CSF) and serum were detected. Comparisons among control, NPRBD and PRBD groups and correlation analyses between RBDSQ score and levels of above factors were performed. Results (1)The frequency of PRBD in PD patients is 31.90%. (2)PRBD group has longer disease duration, more advanced disease stage, severer motor symptoms and more non-motor symptoms than NPRBD group. (3)In CSF, levels of iron, transferrin, NO and IL–1β in PRBD group are prominently increased. RBDSQ score is positively correlated with the levels of iron, transferrin, NO and IL–1β in PD group. Iron level is positively correlated with the levels of NO and IL–1β in PD group. (4)In serum, transferrin level is prominently decreased in PRBD group. PGE2 level in PRBD group is drastically enhanced. RBDSQ score exhibits a positive correlation with PGE2 level in PD group. Conclusions PRBD is common in PD patients. PRBD group has severer motor symptoms and more non-motor symptoms. Excessive iron in brain resulted from abnormal iron metabolism in central and peripheral systems is correlated with PRBD through neuroinflammation. PMID:26431210

  19. Bifunctional (cyclopentadienone)iron-tricarbonyl complexes: Synthesis, computational studies and application in reductive amination

    KAUST Repository

    Moulin, Solenne; Dentel, Hé lè ne; Pagnoux-Ozherelyeva, Anastassiya; Gaillard, Sylvain; Poater, Albert; Cavallo, Luigi; Lohier, Jean Franç ois; Renaud, Jean Luc

    2013-01-01

    . Festival of amination: Two series of modified Knölker's complexes were synthesised and applied in the reductive amination of various carbonyl derivatives with primary or secondary amines (see scheme, TIPS = triisopropylsilyl). For a mechanistic insight

  20. Hydrologically mediated iron reduction/oxidation fluctuations and dissolved organic carbon exports in tidal wetlands

    Science.gov (United States)

    Guimond, J. A.; Seyfferth, A.; Michael, H. A.

    2017-12-01

    Salt marshes are biogeochemical hotspots where large quantities of carbon are processed and stored. High primary productivity and deposition of carbon-laden sediment enable salt marsh soils to accumulate and store organic carbon. Conversely, salt marshes can laterally export carbon from the marsh platform to the tidal channel and eventually the ocean via tidal pumping. However, carbon export studies largely focus on tidal channels, missing key physical and biogeochemical mechanisms driving the mobilization of dissolved organic carbon (DOC) within the marsh platform and limiting our understanding of and ability to predict coastal carbon dynamics. We hypothesize that iron redox dynamics mediate the mobilization/immobilization of DOC in the top 30 cm of salt marsh sediment near tidal channels. The mobilized DOC can then diffuse into the flooded surface water or be advected to tidal channels. To elucidate DOC dynamics driven by iron redox cycles, we measured porewater DOC, Fe(II), total iron, total sulfate, pH, redox potential, and electrical conductivity (EC) beside the creek, at the marsh levee, and in the marsh interior in a mid-latitude tidal salt marsh in Dover, Delaware. Samples were collected at multiple tide stages during a spring and neap tide at depths of 5-75cm. Samples were also collected from the tidal channel. Continuous Eh measurements were made using in-situ electrodes. A prior study shows that DOC and Fe(II) concentrations vary spatially across the marsh. Redox conditions near the creek are affected by tidal oscillations. High tides saturate the soil and decrease redox potential, whereas at low tide, oxygen enters the sediment and increases the Eh. This pattern is always seen in the top 7-10cm of sediment, with more constant low Eh at depth. However, during neap tides, this signal penetrates deeper. Thus, between the creek and marsh levee, hydrology mediates redox conditions. Based on porewater chemistry, if DOC mobilization can be linked to redox

  1. Reductive dechlorination of organochlorine pesticides in soils from an abandoned manufacturing facility by zero-valent iron

    International Nuclear Information System (INIS)

    Cong, Xin; Xue, Nandong; Wang, Shijie; Li, Keji; Li, Fasheng

    2010-01-01

    Several experiments and a model were constructed using conventional granular zero-valent iron (ZVI) particles as the reducing agent to study the reductive dechlorination characteristics of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethane (DDTs) in soils from a former pesticide-manufacturing site. The results showed that ZVI had good ability for the reductive dechlorination for both HCHs and DDTs. The reductive dechlorination of HCHs and DDTs proceeded at different rates. The pseudo first-order constants of HCHs were greater than those of DDTs. The reductive dechlorination rates in a descending order were γ-HCH > δ-HCH > β-HCH > α-HCH > o,p'-DDT > p,p'-DDT > p,p'-DDE. To discuss the major influential factors over the reductive dechlorination rates of HCHs and DDTs by ZVI, 22 quantum chemical descriptors were computed with the density functional theory at B3LYP/6-31G * level, which characterizes different molecular structures and physicochemical properties of HCHs and DDTs. A polyparameter linear free energy relationship (LFER) model was established, which correlates the reductive dechlorination properties of pollutants with their structural descriptors. Using the partial least squares (PLS) analysis, an optimal two-parameter LFER model was established. q + and q Cl - were more important factors in determining the dechlorination rate of OCPs in the chemical reductive reaction. This optimal model was stable and had good predictability. The model study also showed that the coefficient value of q + was 0.511, which positively correlated with the reductive dechlorination rate constant, whereas q Cl - was negatively correlated with it. The reductive dechlorination rate of pollutants appears to be limited mainly by the rate of dissolution in the aqueous phase. This model can be used to explain the degradation potential of organochlorine pesticides (OCPs) and the trend of residues changing during the soil remediation. Therefore, the study is of

  2. Anoxic nitrate reduction coupled with iron oxidation and attenuation of dissolved arsenic and phosphate in a sand and gravel aquifer

    Science.gov (United States)

    Smith, Richard L.; Kent, Douglas B.; Repert, Deborah A.; Böhlke, J.K.

    2017-01-01

    weeks. Additionally, Fe(II)-oxidizing, nitrate-reducing microbial enrichment cultures were obtained from aquifer sediments. Growth experiments with the cultures sequentially produced nitrite and nitrous oxide from nitrate while simultaneously oxidizing Fe(II). Field and culture results suggest that nitrogen oxide reduction and Fe(II) oxidation in the aquifer are a complex interaction of coupled biotic and abiotic reactions. Overall, the results of this study demonstrate that anoxic nitrate-dependent iron oxidation can occur in groundwater; that it could control iron speciation; and that the process can impact the mobility of other chemical species (e.g., phosphate and arsenic) not directly involved in the oxidation–reduction reaction.

  3. Emerging Energy-efficiency and Carbon Dioxide Emissions-reduction Technologies for the Iron and Steel Industry

    Energy Technology Data Exchange (ETDEWEB)

    Hasanbeigi, Ali [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Dept.. China Energy Group; Price, Lynn [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Dept.. China Energy Group; Arens, Marlene [Fraunhofer Inst. for Systems and Innovation Research (ISI), Karlsruhe (Germany)

    2013-01-31

    Iron and steel manufacturing is among the most energy-intensive industries and accounts for the largest share, approximately 27 percent, of global carbon dioxide (CO2) emissions from the manufacturing sector. The ongoing increase in world steel demand means that this industry’s energy use and CO2 emissions continue to grow, so there is significant incentive to develop, commercialize and adopt emerging energy-efficiency and CO2 emissions-reduction technologies for steel production. Although studies from around the world have identified a wide range of energy-efficiency technologies applicable to the steel industry that have already been commercialized, information is limited and/or scattered regarding emerging or advanced energy-efficiency and low-carbon technologies that are not yet commercialized. This report consolidates available information on 56 emerging iron and steel industry technologies, with the intent of providing a well-structured database of information on these technologies for engineers, researchers, investors, steel companies, policy makers, and other interested parties. For each technology included, we provide information on energy savings and environmental and other benefits, costs, and commercialization status; we also identify references for more information.

  4. Effects of ferric iron reduction and regeneration on nitrous oxide and methane emissions in a rice soil.

    Science.gov (United States)

    Huang, Bin; Yu, Kewei; Gambrell, Robert P

    2009-01-01

    A laboratory soil slurry experiment and an outdoor pot experiment were conducted to study effects of ferric iron (Fe(III)) reduction and regeneration on nitrous oxide (N(2)O) and methane (CH(4)) emissions in a rice (Oryza sativa L.) soil. The anoxic slurry experiment showed that enhancing microbial Fe(III) reduction by ferrihydrite amendment (40 mol Fe g(-1)) transitionally stimulated N(2)O production and lowered CH(4) production by 16% during an initial 33-day incubation. Increased regeneration of Fe(III) through a 4-day aeration period in the Fe-amended slurry compared to the control slurry reduced CH(4) emission by 30% in the subsequent 15-day anaerobic incubation. The pot experiment showed that ferrihydrite amendment (63 micromol Fe g(-1)) stimulated N(2)O fluxes in the days following flooding. The Fe amendment suppression on CH(4) emission was obscured in the early season but became significant upon reflooding in the mid- and late-seasons. As a result, seasonal CH(4) emission in Fe-amended pots was 26% lower than the control with a single 2-day drainage and 69% lower with a double 2-day drainage. The reduction in CH(4) emission upon reflooding from the Fe-amended pots was mainly attributed to the increased Fe(III) regeneration during drainage showing a mechanism of Fe(III) regeneration in mitigating CH(4) emission by short-term drainage in flooded soils.

  5. IRON DYNAMICS AND ITS RELATION TO SOIL REDOX POTENTIAL AND PLANT GROWTH IN ACID SULPHATE SOIL OF SOUTH KALIMANTAN, INDONESIA

    Directory of Open Access Journals (Sweden)

    Wahida Annisa

    2017-01-01

    Full Text Available Organic matter has a function to maintain reductive conditions and to chelate toxic elements in acid sulphate soils. The study aimed to assess the dynamics of ferrous iron (Fe2+ in acid sulphate soil and its correlation with soil redox potential (Eh and plant growth. The experiment was arranged in two factorial randomized block design with three replications. The first factor was two types of organic matter: (1 control (without organic matter, (2 rice straw and (3 rush weed (Eleocharis dulcis. The second factor was time of decomposition of organic matter: I1 = 2 weeks, I2 = 4 weeks, I3 = 8 weeks, and I4 = 12 weeks (farmer practice. The results showed that concentration of ferrous iron in the soil ranged from 782 to 1308 mg kg-1 during the rice growing season. The highest constant rate of iron reduction (k F2+ was observed on application of rice straw and rush weed with decomposition time of 8 weeks with the k Fe2+ value of 0.016 and 0.011 per day, respectively, while the ferrous iron formation without organic matter had the k Fe2+ value of 0.077 per day. The ferric iron (Fe3+ reduction served as a function of soil Eh as indicated by the negative correlation of ferrous iron and Eh (r = -0.856*. Organic matter decreased exchangeable iron due to chelating reaction. Iron concentration in roots was negatively correlated with soil soluble iron (r = -0.62*. Application of rice straw decomposed for 8 weeks increased the height of rice plant up to 105.67 cm. The score of Fe2+ toxicity at 8 weeks after planting ranged from 2 to 3, so rice crop did not show iron toxicity symptoms. 

  6. Improved Understanding of Microbial Iron and Sulfate Reduction Through a Combination of Bottom-up and Top-down Functional Proteomics Assays

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, Ruth [Cornell Univ., Ithaca, NY (United States)

    2016-02-28

    Our overall goal was to improve the understanding of microbial iron and sulfate reduction by evaluating a diverse iron and sulfate reducing organisms utilizing a multi-omics approach combining “top-down” and “bottom-up” omics methodologies. We initiated one of the first combined comparative genomics, shotgun proteomics, RTqPCR, and heterologous expression studies in pursuit of our project objectives. Within the first year of this project, we created a new bioinformatics tool for ortholog identification (“SPOCS”). SPOCS is described in our publication, Curtis et al., 2013. Using this tool we were able to identify conserved orthologous groups across diverse iron and sulfate reducing microorganisms from Firmicutes, gamma-proteobacteria and delta-proteobacteria. For six iron and sulfate reducers we also performed shotgun proteomics (“bottom-up” proteomics including accurate mass and time (AMT) tag and iTRAQ approaches). Cultures include Gram (-) and Gram (+) microbes. Gram (-) were: Geobacter sulfureducens (grown on iron citrate and fumarate), Geobacter bemidjiensis (grown on iron citrate and fumarate), Shewanella oneidiensis (grown on iron citrate and fumarate) and Anaeromyxobacter dehalogenans (grown on iron citrate and fumarate). Although all cultures grew on insoluble iron, the iron precipitates interfered with protein extraction and analysis; which remains a major challenge for researchers in disparate study systems. Among the Gram (-) organisms studied, Anaeromyxobacter dehalogenans remains the most poorly characterized. Yet, it is arguably the most versatile organisms we studied. In this work we have used comparative proteomics to hypothesize which two of the dozens of predicted c-type cytochromes within Anaeromyxobacter dehalogenans may be directly involved in soluble iron reduction. Unfortunately, heterologous expression of these Anaeromyxobacter dehalogenans ctype cytochromes led to poor protein production and/or formation of inclusion bodies

  7. [Reduction of 137caesium contamination in wild boars by supplementing offered food with ammonium-iron-hexa-cyanoferrate].

    Science.gov (United States)

    Morfeld, P; Reddemann, J; Schungel, P; Kienzle, E

    2014-01-01

    This replication study investigated whether the 137caesium (137Cs) contamination of wild boars could be relevantly reduced under field conditions by adding ammonium-iron-hexa-cyanoferrate (AFCF; Prussian blue) to the food. In 285 wild boars that had been shot in six Bavarian hunting territories during the season (November until May) between 01 November 2010 and 10 December 2011 137Cs contamination was analysed. Thirty-five animals originated from two hunting territories in which offered food had been supplemented with 1250 mg AFCF per kilogram food. The control animals showed a mean 137Cs contamination of 522 Bq/kg lean skeletal muscle meat. Direct (univariable) comparisons of the two experimental territories with the four control territories yielded a mean reduction in 137Cs contamination due to Prussian bluefeeding by -211 Bq/kg (p contamination by -380 Bq/kg due to the feeding of Prussian blue in other territories.

  8. Size Control of Iron Oxide Nanoparticles Using Reverse Microemulsion Method: Morphology, Reduction, and Catalytic Activity in CO Hydrogenation

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Housaindokht

    2013-01-01

    Full Text Available Iron oxide nanoparticles were prepared by microemulsion method and evaluated in Fischer-Tropsch synthesis. The precipitation process was performed in a single-phase microemulsion operating region. Different HLB values of surfactant were prepared by mixing of sodium dodecyl sulfate (SDS and Triton X-100. Transmission electron microscopy (TEM, surface area, pore volume, average pore diameter, pore size distribution, and XRD patterns were used to analyze size distribution, shape, and structure of precipitated hematite nanoparticles. Furthermore, temperature programmed reduction (TPR and catalytic activity in CO hydrogenation were implemented to assess the performance of the samples. It was found that methane and CO2 selectivity and also the syngas conversion increased as the HLB value of surfactant decreased. In addition, the selectivity to heavy hydrocarbons and chain growth probability (α decreased by decreasing the catalyst crystal size.

  9. Effect of repeated pesticide applications on soil properties in cotton fields: I. Impact on microbes, iron reduction capacity and respiration

    International Nuclear Information System (INIS)

    Vig, K.; Singh, D.K.; Agarwal, H.C.; Dhawan, A.K.; Dureja, P.

    2001-01-01

    Soil microorganisms have a primary catabolic role in the environment through degradation of plant and animal residues. The activities of microorganisms in soil are thus, essential to the global cycling of nutrients. As these pesticides are designed to be biologically active, their continuous use might affect soil microflora either by changing their properties or their numbers, which may lead to impairment in soil fertility. Soil was analyzed for microbial numbers, iron reduction capacity and respiration. Stimulatory, inhibitory or no effects of insecticide treatments were observed on microbes and microbial activities. The insecticides used had only temporary effects on microbes and their activities which disappeared either before the next insecticide treatment was carried out or at the end of experimental period. (author)

  10. Hollow Spheres of Iron Carbide Nanoparticles Encased in Graphitic Layers as Oxygen Reduction Catalysts

    DEFF Research Database (Denmark)

    Hu, Yang; Jensen, Jens Oluf; Zhang, Wei

    2014-01-01

    Nonprecious metal catalysts for the oxygen reduction reaction are the ultimate materials and the foremost subject for low‐temperature fuel cells. A novel type of catalysts prepared by high‐pressure pyrolysis is reported. The catalyst is featured by hollow spherical morphologies consisting...

  11. Characterization of the corrinoid iron-sulfur protein tetrachloroethene reductive dehalogenase of Dehalobacter restrictus

    NARCIS (Netherlands)

    Maillard, J.; Schumacher, W.; Vazquez, F.; Regeard, C.; Hagen, W.R.; Holliger, C.

    2003-01-01

    The membrane-bound tetrachloroethene reductive dehalogenase (PCE-RDase) (PceA; EC 1.97.1.8), the terminal component of the respiratory chain of Dehalobacter restrictus, was purified 25-fold to apparent electrophoretic homogeneity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a

  12. pH controls over methanogenesis and iron reduction along soil depth profile in Arctic tundra

    Science.gov (United States)

    Zheng, J.; Gu, B.; Wullschleger, S. D.; Graham, D. E.

    2017-12-01

    Increasing soil temperature in the Arctic is expected to accelerate rates of soil organic matter decomposition. However, the magnitude of this impact is uncertain due to the many physical, chemical, and biological processes that control the decomposition pathways. Varying soil redox conditions present a key control over pathways of organic matter decomposition by diverting the flow of reductants among different electron accepting processes and further driving acid-base reactions that alter soil pH. In this study we investigated the pH controls over anaerobic carbon mineralization, methanogenesis, Fe(III) reduction and the interplay between these processes across a range of pH and redox conditions. pH manipulation experiments were conducted by incubating soils representing organic, mineral, cryoturbated transitional layers and permafrost. In the experiments we sought to understand (1) if methanogenesis or Fe(III) reduction had similar pH optima; (2) if this pH response also occurs at `upstream' fermentation process; and (3) if pH alters organo-mineral association or organic matter sorption and desorption and its availability for microbial degradation. Our preliminary results suggest that the common bell-shaped pH response curve provides a good fit for both Fe(III) reduction and methanogenesis, with optimum pH at 6.0-7.0. Exceptions to this were found in transitional layer where methanogenesis rates positively correlated with increasing pH, with maximum rates measured at pH 8.5. It is likely that the transitional layer harbors distinct groups of methanogens that prefer a high pH. Variations in the optimum pH of Fe(III) reduction and methanogenesis may play a significant role in regulating organic matter decomposition pathways and thus greenhouse gas production in thawing soils. These results support biogeochemical modeling efforts to accurately simulate organic matter decomposition under changing redox and pH conditions.

  13. On the relation between primary and eutectic solidification structures in gray iron

    International Nuclear Information System (INIS)

    Elmquist, L; Sonawane, P A

    2012-01-01

    The solidification of hypoeutectic gray cast iron starts with the nucleation of primary austenite crystals. Before graphite is nucleated, and the eutectic structure is formed, these crystals start to grow as columnar or equiaxed dendrites. However, very little is known about these dendrites, and especially how they influence the subsequent eutectic structure. Besides, it has previously been shown that the primary solidification structure influences the formation of defects. Shrinkage porosity was found between the dendrites, in the grain boundaries, and the formation of the primary solidification structure was found to influence problems related to metal expansion penetration. Therefore a better understanding about the formation of this structure is of importance. In this work, different inoculants and their influence on the formation of the micro- and macrostructures has been investigated. The inoculants considered are commercially used inoculants, i.e. inoculants used in the foundries, as well as different iron powders. The addition of iron powder is used to promote the primary solidification structure. It is shown that the nucleation of the dendrites is influenced by the amount of iron powder. Secondary dendrite arm spacing is a quantitative measurement in the microstructure related to these dendrites, which in turn depends on the solidification time. Eutectic cell size, on the other hand, is found to depend on secondary dendrite arm spacing. It is shown how the addition of inoculants influences both primary and eutectic solidification structures, and how they are related to each other.

  14. Zonulin, iron status, and anemia in kidney transplant recipients: are they related?

    Science.gov (United States)

    Malyszko, Jolanta; Koc-Zorawska, E; Levin-Iaina, N; Malyszko, Jacek

    2014-10-01

    In patients after kidney transplantation, anemia is relatively common and is associated with impaired kidney function, subclinical inflammatory state, and immunosuppressive treatment. Zonulin-prehaptoglobin-2, a newly discovered protein, is necessary for integrity of intracellular tight junctions in the gut. Taking into consideration iron metabolism, including its absorption in the gut, we designed a cross-sectional study to look for the possible interactions among zonulin, iron status, and anemia in kidney transplant recipients. The study was performed on 72 stable kidney transplant recipients and 22 healthy volunteers. Zonulin, iron status, and inflammatory markers were assessed with the use of commercially available kits. Zonulin was significantly lower in kidney allograft recipients than in healthy volunteers (P Zonulin correlated with systolic blood pressure (r = -0.33; P Zonulin was not affected by sex, type of immunosuppressive therapy, presence of diabetes, coronary artery disease, heart failure, hypertension, or cause of end-stage renal disease. Zonulin was not related to any of the iron parameters studied. In multiple regression analysis, predictors of zonulin were total protein and thyroglobulin-binding protein, explaining 46% of variation. Zonulin, with its poorly defined function, does not seem to play a role in the anemia in kidney allograft recipients; however, it seems to be related to the absorption process in the gut.

  15. Role of vitamin C as an adjuvant therapy to different iron chelators in young β-thalassemia major patients: efficacy and safety in relation to tissue iron overload.

    Science.gov (United States)

    Elalfy, Mohsen S; Saber, Maha M; Adly, Amira Abdel Moneam; Ismail, Eman A; Tarif, Mohamed; Ibrahim, Fatma; Elalfy, Omar M

    2016-03-01

    Vitamin C, as antioxidant, increases the efficacy of deferoxamine (DFO). To investigate the effects of vitamin C as an adjuvant therapy to the three used iron chelators in moderately iron-overloaded young vitamin C-deficient patients with β-thalassemia major (β-TM) in relation to tissue iron overload. This randomized prospective trial that included 180 β-TM vitamin C-deficient patients were equally divided into three groups (n = 60) and received DFO, deferiprone (DFP), and deferasirox (DFX). Patients in each group were further randomized either to receive vitamin C supplementation (100 mg daily) or not (n = 30). All patients received vitamin C (group A) or no vitamin C (group B) were followed up for 1 yr with assessment of transfusion index, hemoglobin, iron profile, liver iron concentration (LIC) and cardiac magnetic resonance imaging (MRI) T2*. Baseline vitamin C was negatively correlated with transfusion index, serum ferritin (SF), and LIC. After vitamin C therapy, transfusion index, serum iron, SF, transferrin saturation (Tsat), and LIC were significantly decreased in group A patients, while hemoglobin and cardiac MRI T2* were elevated compared with baseline levels or those in group B without vitamin C. The same improvement was found among DFO-treated patients post-vitamin C compared with baseline data. DFO-treated patients had the highest hemoglobin with the lowest iron, SF, and Tsat compared with DFP or DFX subgroups. Vitamin C as an adjuvant therapy possibly potentiates the efficacy of DFO more than DFP and DFX in reducing iron burden in the moderately iron-overloaded vitamin C-deficient patients with β-TM, with no adverse events. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Assessment of air quality in and around a steel industry with direct reduction iron route.

    Science.gov (United States)

    Jena, Pradip K; Behera, Dillip K; Mishra, C S K; Mohanty, Saswat K

    2011-10-01

    The coal based Direct Reduced Iron (DRI) route for secondary steel production is now a preferred choice in India. Steel making is invariably associated with emission of air pollutants into the environment. Air quality monitoring was carried out in Winter, Summer and Rainy seasons of 2008 in eight monitoring stations in the work zone and five stations in the residential zone of an Integrated Steel Industry located in Orissa state, India. Four air quality parameters i.e. SPM, RSPM, SO2 and NO2 were monitored. Mean SPM and RSPM values were found to be significantly high (p < 0.01) at stations nearer to source in both work zone and residential zone .The highest average SPM and RSPM values in the work zone recorded were 4869 microg/m3 and 1420 microg/m3 and in the residential zone 294 microg/m3 and 198 microg/m3 respectively. No significant difference in the SO2 and NO2 levels was observed between the work and residential zones. In general, the values of air pollutants were highest in Winter followed by Summer and Rainy season. SPM and RSPM values exceeded the National Air Quality Standards (NAAQS) in both the residential and work zones.

  17. Novel mode of microbial energy metabolism: organic carbon oxidation coupled to dissimilatory reduction of iron or manganese.

    Science.gov (United States)

    Lovley, D R; Phillips, E J

    1988-06-01

    A dissimilatory Fe(III)- and Mn(IV)-reducing microorganism was isolated from freshwater sediments of the Potomac River, Maryland. The isolate, designated GS-15, grew in defined anaerobic medium with acetate as the sole electron donor and Fe(III), Mn(IV), or nitrate as the sole electron acceptor. GS-15 oxidized acetate to carbon dioxide with the concomitant reduction of amorphic Fe(III) oxide to magnetite (Fe(3)O(4)). When Fe(III) citrate replaced amorphic Fe(III) oxide as the electron acceptor, GS-15 grew faster and reduced all of the added Fe(III) to Fe(II). GS-15 reduced a natural amorphic Fe(III) oxide but did not significantly reduce highly crystalline Fe(III) forms. Fe(III) was reduced optimally at pH 6.7 to 7 and at 30 to 35 degrees C. Ethanol, butyrate, and propionate could also serve as electron donors for Fe(III) reduction. A variety of other organic compounds and hydrogen could not. MnO(2) was completely reduced to Mn(II), which precipitated as rhodochrosite (MnCO(3)). Nitrate was reduced to ammonia. Oxygen could not serve as an electron acceptor, and it inhibited growth with the other electron acceptors. This is the first demonstration that microorganisms can completely oxidize organic compounds with Fe(III) or Mn(IV) as the sole electron acceptor and that oxidation of organic matter coupled to dissimilatory Fe(III) or Mn(IV) reduction can yield energy for microbial growth. GS-15 provides a model for how enzymatically catalyzed reactions can be quantitatively significant mechanisms for the reduction of iron and manganese in anaerobic environments.

  18. Rhizosphere microbial community structure in relation to root location and plant iron nutritional status.

    Science.gov (United States)

    Yang, C H; Crowley, D E

    2000-01-01

    Root exudate composition and quantity vary in relation to plant nutritional status, but the impact of the differences on rhizosphere microbial communities is not known. To examine this question, we performed an experiment with barley (Hordeum vulgare) plants under iron-limiting and iron-sufficient growth conditions. Plants were grown in an iron-limiting soil in root box microcosms. One-half of the plants were treated with foliar iron every day to inhibit phytosiderophore production and to alter root exudate composition. After 30 days, the bacterial communities associated with different root zones, including the primary root tips, nonelongating secondary root tips, sites of lateral root emergence, and older roots distal from the tip, were characterized by using 16S ribosomal DNA (rDNA) fingerprints generated by PCR-denaturing gradient gel electrophoresis (DGGE). Our results showed that the microbial communities associated with the different root locations produced many common 16S rDNA bands but that the communities could be distinguished by using correspondence analysis. Approximately 40% of the variation between communities could be attributed to plant iron nutritional status. A sequence analysis of clones generated from a single 16S rDNA band obtained at all of the root locations revealed that there were taxonomically different species in the same band, suggesting that the resolving power of DGGE for characterization of community structure at the species level is limited. Our results suggest that the bacterial communities in the rhizosphere are substantially different in different root zones and that a rhizosphere community may be altered by changes in root exudate composition caused by changes in plant iron nutritional status.

  19. Enhancing the Process of Anaerobic Ammonium Oxidation Coupled to Iron Reduction in Constructed Wetland Mesocosms with Supplementation of Ferric Iron Hydroxides

    Science.gov (United States)

    Shuai, W.; Jaffe, P. R.

    2017-12-01

    Effective ammonium (NH4+) removal has been a challenge in wastewater treatment processes. Aeration, which is required for the conventional NH4+ removal approach by ammonium oxidizing bacteria, is an energy intensive process during the operation of wastewater treatment plant. The efficiency of NH4+ oxidation in natural systems is also limited by oxygen transfer in water and sediments. The objective of this study is to enhance NH4+ removal by applying a novel microbial process, anaerobic NH4+ oxidation coupled to iron (Fe) reduction (also known as Feammox), in constructed wetlands (CW). Our studies have shown that an Acidimicrobiaceae bacterium named A6 can carry out the Feammox process using ferric Fe (Fe(III)) minerals like ferrihydrite as their electron acceptor. To investigate the properties of the Feammox process in CW as well as the influence of electrodes, Feammox bacterium A6 was inoculated in planted CW mesocosms with electrodes installed at multiple depths. CW mesocosms were operated using high NH4+ nutrient solution as inflow under high or low sediment Fe(III) level. During the operation, NH4+ and ferrous Fe concentration, pore water pH, voltages between electrodes, oxidation reduction potential and dissolved oxygen were measured. At the end of the experiment, CW sediment samples at different depths were taken, DNAs were extracted and quantitative polymerase chain reaction and pyrosequencing were performed to analyze the microbial communities. The results show that the high Fe level CW mesocosm has much higher NH4+ removal ability than the low Fe level CW mesocosm after Fe-reducing conditions are developed. This indicates the enhanced NH4+ removal can be attributed to elevated Feammox activity in high Fe level CW mesocosm. The microbial community structures are different in high or low Fe level CW mesocosms and on or away from the installed electrodes. The voltages between cathode and anode increased after the injection of A6 enrichment culture in low Fe

  20. Reduction of 137caesium contamination in wild boars by supplementing offered food with ammonium-iron-hexa-cyanoferrate

    International Nuclear Information System (INIS)

    Morfeld, P.; Kienzle, E.

    2014-01-01

    This replication study investigated whether the 137 caesium ( 137 Cs) contamination of wild boars could be relevantly reduced under field conditions by adding ammonium-iron-hexa-cyanoferrate (AFCF; Prussian blue) to the food. In 285 wild boars that had been shot in six Bavarian hunting territories during the season (November until May) between 01 November 2010 and 10 December 2011 137 Cs contamination was analysed. Thirty-five animals originated from two hunting territories in which offered food had been supplemented with 1250 mg AFCF per kilogram food. The control animals showed a mean 137 Cs contamination of 522 Bq/kg lean skeletal muscle meat. Direct (univariable) comparisons of the two experimental territories with the four control territories yielded a mean reduction in 137 Cs contamination due to Prussian bluefeeding by -211 Bq/kg (p < 0.001). Multivariable mo dels that took potential confounders into account (age, weight, sex, hunting date, territory) estimated the effect to be -344 Bq/kg (p < 0.05). This replication study confirmed the finding of Kienzle et al. (12) who described a statistically significant reduction in 137 Cs contamination by -380 Bq/kg due to the feeding of Prussian blue in other territories. [de

  1. Flavins secreted by roots of iron-deficient Beta vulgaris enable mining of ferric oxide via reductive mechanisms.

    Science.gov (United States)

    Sisó-Terraza, Patricia; Rios, Juan J; Abadía, Javier; Abadía, Anunciación; Álvarez-Fernández, Ana

    2016-01-01

    Iron (Fe) is abundant in soils but generally poorly soluble. Plants, with the exception of Graminaceae, take up Fe using an Fe(III)-chelate reductase coupled to an Fe(II) transporter. Whether or not nongraminaceous species can convert scarcely soluble Fe(III) forms into soluble Fe forms has deserved little attention so far. We have used Beta vulgaris, one among the many species whose roots secrete flavins upon Fe deficiency, to study whether or not flavins are involved in Fe acquisition. Flavins secreted by Fe-deficient plants were removed from the nutrient solution, and plants were compared with Fe-sufficient plants and Fe-deficient plants without flavin removal. Solubilization of a scarcely soluble Fe(III)-oxide was assessed in the presence or absence of flavins, NADH (nicotinamide adenine dinucleotide, reduced form) or plant roots, and an Fe(II) trapping agent. The removal of flavins from the nutrient solution aggravated the Fe deficiency-induced leaf chlorosis. Flavins were able to dissolve an Fe(III)-oxide in the presence of NADH. The addition of extracellular flavins enabled roots of Fe-deficient plants to reductively dissolve an Fe(III)-oxide. We concluded that root-secretion of flavins improves Fe nutrition in B. vulgaris. Flavins allow B. vulgaris roots to mine Fe from Fe(III)-oxides via reductive mechanisms. © 2015 CSIC New Phytologist © 2015 New Phytologist Trust.

  2. Variation of iron redox kinetics and its relation with molecular composition of standard humic substances at circumneutral pH.

    Directory of Open Access Journals (Sweden)

    Ying Ping Lee

    Full Text Available Oxidation and reduction kinetics of iron (Fe and proportion of steady-state Fe(II concentration relative to total dissolved Fe (steady-state Fe(II fraction were investigated in the presence of various types of standard humic substances (HS with particular emphasis on the photochemical and thermal reduction of Fe(III and oxidation of Fe(II by dissolved oxygen (O2 and hydrogen peroxide (H2O2 at circumneutral pH (pH 7-8. Rates of Fe(III reduction were spectrophotometrically determined by a ferrozine method under the simulated sunlight and dark conditions, whereas rates of Fe(II oxidation were examined in air-saturated solution using luminol chemiluminescence technique. The reduction and oxidation rate constants were determined to substantially vary depending on the type of HS. For example, the first-order rate constants varied by up to 10-fold for photochemical reduction and 7-fold for thermal reduction. The degree of variation in Fe(II oxidation was larger for the H2O2-mediated reaction compared to the O2-mediated reaction (e.g., 15- and 3-fold changes for the former and latter reactions, respectively, at pH 8. The steady-state Fe(II fraction under the simulated sunlight indicated that the Fe(II fraction varies by up to 12-fold. The correlation analysis indicated that variation of Fe(II oxidation is significantly associated with aliphatic content of HS, suggesting that Fe(II complexation by aliphatic components accelerates Fe(II oxidation. The reduction rate constant and steady-state Fe(II fractions in the presence of sunlight had relatively strong positive relations with free radical content of HS, possibly due to the reductive property of radical semiquinone in HS. Overall, the findings in this study indicated that the Fe reduction and oxidation kinetics and resultant Fe(II formation are substantially influenced by chemical properties of HS.

  3. Scenario analysis on CO2 emissions reduction potential in China's iron and steel industry

    International Nuclear Information System (INIS)

    Wang Ke; Wang Can; Lu Xuedu; Chen Jining

    2007-01-01

    The international climate community has begun to assess a range of possible options for strengthening the international climate change effort after 2012. Analysis of the potential for sector-based emissions reduction and relevant mitigation options will provide the necessary background information for the debate. In order to assess the CO 2 abatement potential of China's steel industry, a model was developed using LEAP software to generate 3 different CO 2 emission scenarios for the industry from 2000 to 2030. The abatement potentials of different scenarios were compared, and their respective feasibilities were assessed according to the cost information. High priority abatement measures were then identified. The results show that the average CO 2 abatement per year in the Recent Policy scenario and in the New Policy scenario, compared with the reference scenario, are 51 and 107 million tons, respectively. The corresponding total incremental costs are 9.34 and 80.95 billion dollars. It is concluded that there is great potential for CO 2 abatement in China's steel industry. Adjusting the structure of the industry and technological advancement will play an important role in emissions reduction. Successful implementation of current sustainable development policies and measures will result in CO 2 abatement at a low cost. However, to achieve higher levels of abatement, the cost will increase dramatically. In the near future, specific energy conservation technologies such as dry coke quenching, exhaust gas and heat recovery equipment will be of great significance. However, taking a long term perspective, emissions reduction will rely more on the adjustment of production processes and the application of more modern large scale plants. Advanced blast furnace technology will inevitably play an important role

  4. Reduction of neptunium(V) and uranium(VI) in bicarbonate solutions by iron(II)

    International Nuclear Information System (INIS)

    Gogolev, A.V.; Zakharova, E.V.; Rodygina, N.I.; Fedoseev, A.M.; Shilov, V.P.

    2006-01-01

    Interaction of Np(VI) and Fe(II) compounds in bicarbonate solutions is investigated. Interaction of Np(V) with Fe(II) in the presence of phthalate-ions is studied briefly. Fe(II) compounds reduce Np(V) compounds in saturated with Ar or CO 2 solutions with any bicarbonate-ion concentrations. Chemical reaction kinetics is studied. Reduction of U(VI) by Fe(II) compounds takes place in the case of diluted bicarbonate solutions. UO 2 and FeOOH are products of reaction at raised temperatures [ru

  5. Synthesis of high intrinsic loss power aqueous ferrofluids of iron oxide nanoparticles by citric acid-assisted hydrothermal-reduction route

    International Nuclear Information System (INIS)

    Behdadfar, Behshid; Kermanpur, Ahmad; Sadeghi-Aliabadi, Hojjat; Morales, Maria del Puerto; Mozaffari, Morteza

    2012-01-01

    Monodispersed aqueous ferrofluids of iron oxide nanoparticle were synthesized by hydrothermal-reduction route. They were characterized by X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning and transmission electron microscopy and dynamic light scattering. The results showed that certain concentrations of citric acid (CA) are required to obtain only magnetic iron oxides with mean particle sizes around 8 nm. CA acts as a modulator and reducing agent in iron oxide formation which controls nanoparticle size. The XRD, magnetic and heating measurements showed that the temperature and time of hydrothermal reaction can affect the magnetic properties of obtained ferrofluids. The synthesized ferrofluids were stable at pH 7. Their mean hydrodynamic size was around 80 nm with polydispersity index (PDI) of 0.158. The calculated intrinsic loss power (ILP) was 9.4 nHm 2 /kg. So this clean and cheap route is an efficient way to synthesize high ILP aqueous ferrofluids applicable in magnetic hyperthermia. - Graphical abstract: Monodispersed aqueous ferrofluids of iron oxide nanoparticles were synthesized by hydrothermal-reduction method with citric acid as reductant which is an efficient way to synthesize aqueous ferrofluids applicable in magnetic hyperthermia. Highlights: ► Aqueous iron oxide ferrofluids were synthesized by hydrothermal-reduction route. ► Citric acid acted as reducing agent and surfactant in the route. ► This is a facile, low energy and environmental friendly route. ► The aqueous iron oxide ferrofluids were monodispersed and stable at pH of 7. ► The calculated intrinsic loss power of the synthesized ferrofluids was very high.

  6. 57Fe-Mössbauer spectroscopy and electrochemical activities of graphitic layer encapsulated iron electrocatalysts for the oxygen reduction reaction

    DEFF Research Database (Denmark)

    Zhong, Lijie; Frandsen, Cathrine; Mørup, Steen

    2018-01-01

    Graphitic layer encapsulated iron based nanoparticles (G@FeNPs) have recently been disclosed as an interesting type of highly active electrocatalysts for the oxygen reduction reaction (ORR). However, the complex composition of the metal-containing components and their contributions in catalysis r...

  7. Kinetics of nitrate adsorption and reduction by nano-scale zero valent iron (NZVI): Effect of ionic strength and initial pH

    DEFF Research Database (Denmark)

    Kim, Do-Gun; Hwang, Yuhoon; Shin, Hang-Sik

    2016-01-01

    Kinetic models for pollutants reduction by Nano-scale Zero Valent Iron (NZVI) were tested in this study to gain a better understanding and description of the reaction. Adsorption kinetic models and a heterogeneous catalytic reaction kinetic equation were proposed for nitrate removal and for ammon...

  8. Simultaneous adsorption and reduction of U(VI) on reduced graphene oxide-supported nanoscale zerovalent iron

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yubing [School of Environment and Chemical Engineering, North China Electric Power University, Beijing 102206 (China); Institute of Plasma Physics, Chinese Academy of Science, P.O. Box 1126, Hefei, 230031 (China); Ding, Congcong; Cheng, Wencai [Institute of Plasma Physics, Chinese Academy of Science, P.O. Box 1126, Hefei, 230031 (China); Wang, Xiangke, E-mail: xkwang@ipp.ac.cn [School of Environment and Chemical Engineering, North China Electric Power University, Beijing 102206 (China); Faculty of Engineering, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

    2014-09-15

    Graphical abstract: - Highlights: • Sorption and in-situ reduction of U(VI) is observed. • The composites are more effective for U(VI) removal and solidification. • The inner-sphere surface complexes are observed. - Abstract: The reduced graphene oxide-supported nanoscale zero-valent iron (nZVI/rGO) composites were synthesized by chemical deposition method and were characterized by SEM, high resolution TEM, Raman and potentiometric acid-base titrations. The characteristic results showed that the nZVI nanoparticles can be uniformly dispersed on the surface of rGO. The removal of U(VI) on nZVI/rGO composites as a function of contact time, pH and U(VI) initial concentration was investigated by batch technique. The removal kinetics of U(VI) on nZVI and nZVI/rGO were well simulated by a pseudo-first-order kinetic model and pseudo-second-order kinetic model, respectively. The presence of rGO on nZVI nanoparticles increased the reaction rate and removal capacity of U(VI) significantly, which was attributed to the chemisorbed OH{sup −} groups of rGO and the massive enrichment of Fe{sup 2+} on rGO surface by XPS analysis. The XRD analysis revealed that the presence of rGO retarded the transformation of iron corrosion products from magnetite/maghemite to lepidocrocite. According to the fitting of EXAFS spectra, the U-C (at ∼2.9 Å) and U-Fe (at ∼3.2 Å) shells were observed, indicating the formation of inner-sphere surface complexes on nZVI/rGO composites. Therefore, the nZVI/rGO composites can be suitable as efficient materials for the in-situ remediation of uranium-contaminated groundwater in the environmental pollution management.

  9. Tungsten carbide encapsulated in nitrogen-doped carbon with iron/cobalt carbides electrocatalyst for oxygen reduction reaction

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jie; Chen, Jinwei, E-mail: jwchen@scu.edu.cn; Jiang, Yiwu; Zhou, Feilong; Wang, Gang; Wang, Ruilin, E-mail: rl.wang@scu.edu.cn

    2016-12-15

    Graphical abstract: A hybrid catalyst was prepared via a quite green and simple method to achieve an one-pot synthesis of the N-doping carbon, tungsten carbides, and iron/cobalt carbides. It exhibited comparable electrocatalytic activity, higher durability and ability to methanol tolerance compared with commercial Pt/C to ORR. - Highlights: • A novel type of hybrid Fe/Co/WC@NC catalysts have been successfully synthesized. • The hybrid catalyst also exhibited better durability and methanol tolerance. • Multiple effective active sites of Fe{sub 3}C, Co{sub 3}C, WC, and NC help to improve catalytic performance. - Abstract: This work presents a type of hybrid catalyst prepared through an environmental and simple method, combining a pyrolysis of transition metal precursors, a nitrogen-containing material, and a tungsten source to achieve a one-pot synthesis of N-doping carbon, tungsten carbides, and iron/cobalt carbides (Fe/Co/WC@NC). The obtained Fe/Co/WC@NC consists of uniform Fe{sub 3}C and Co{sub 3}C nanoparticles encapsulated in graphitized carbon with surface nitrogen doping, closely wrapped around a plate-like tungsten carbide (WC) that functions as an efficient oxygen reduction reaction (ORR) catalyst. The introduction of WC is found to promote the ORR activity of Fe/Co-based carbide electrocatalysts, which is attributed to the synergistic catalysts of WC, Fe{sub 3}C, and Co{sub 3}C. Results suggest that the composite exhibits comparable electrocatalytic activity, higher durability, and ability for methanol tolerance compared with commercial Pt/C for ORR in alkaline electrolyte. These advantages make Fe/Co/WC@NC a promising ORR electrocatalyst and a cost-effective alternative to Pt/C for practical application as fuel cell.

  10. Modelling CEC variations versus structural iron reduction levels in dioctahedral smectites. Existing approaches, new data and model refinements.

    Science.gov (United States)

    Hadi, Jebril; Tournassat, Christophe; Ignatiadis, Ioannis; Greneche, Jean Marc; Charlet, Laurent

    2013-10-01

    A model was developed to describe how the 2:1 layer excess negative charge induced by the reduction of Fe(III) to Fe(II) by sodium dithionite buffered with citrate-bicarbonate is balanced and applied to nontronites. This model is based on new experimental data and extends structural interpretation introduced by a former model [36-38]. The 2:1 layer negative charge increase due to Fe(III) to Fe(II) reduction is balanced by an excess adsorption of cations in the clay interlayers and a specific sorption of H(+) from solution. Prevalence of one compensating mechanism over the other is related to the growing lattice distortion induced by structural Fe(III) reduction. At low reduction levels, cation adsorption dominates and some of the incorporated protons react with structural OH groups, leading to a dehydroxylation of the structure. Starting from a moderate reduction level, other structural changes occur, leading to a reorganisation of the octahedral and tetrahedral lattice: migration or release of cations, intense dehydroxylation and bonding of protons to undersaturated oxygen atoms. Experimental data highlight some particular properties of ferruginous smectites regarding chemical reduction. Contrary to previous assumptions, the negative layer charge of nontronites does not only increase towards a plateau value upon reduction. A peak is observed in the reduction domain. After this peak, the negative layer charge decreases upon extended reduction (>30%). The decrease is so dramatic that the layer charge of highly reduced nontronites can fall below that of its fully oxidised counterpart. Furthermore, the presence of a large amount of tetrahedral Fe seems to promote intense clay structural changes and Fe reducibility. Our newly acquired data clearly show that models currently available in the literature cannot be applied to the whole reduction range of clay structural Fe. Moreover, changes in the model normalising procedure clearly demonstrate that the investigated low

  11. Silver/iron oxide/graphitic carbon composites as bacteriostatic catalysts for enhancing oxygen reduction in microbial fuel cells

    Science.gov (United States)

    Ma, Ming; You, Shijie; Gong, Xiaobo; Dai, Ying; Zou, Jinlong; Fu, Honggang

    2015-06-01

    Biofilms from anode heterotrophic bacteria are inevitably formed over cathodic catalytic sites, limiting the performances of single-chamber microbial fuel cells (MFCs). Graphitic carbon (GC) - based nano silver/iron oxide (AgNPs/Fe3O4/GC) composites are prepared from waste pomelo skin and used as antibacterial oxygen reduction catalysts for MFCs. AgNPs and Fe3O4 are introduced in situ into the composites by one-step carbothermal reduction, enhancing their conductivity and catalytic activity. To investigate the effects of Fe species on the antibacterial and catalytic properties, AgNPs/Fe3O4/GC is washed with sulfuric acid (1 mol L-1) for 0.5 h, 1 h, and 5 h and marked as AgNPs/Fe3O4/GC-x (x = 0.5 h, 1 h and 5 h, respectively). A maximum power density of 1712 ± 35 mW m-2 is obtained by AgNPs/Fe3O4/GC-1 h, which declines by 4.12% after 17 cycles. Under catalysis of all AgNP-containing catalysts, oxygen reduction reaction (ORR) proceeds via the 4e- pathway, and no toxic effects to anode microorganisms result from inhibiting the cathodic biofilm overgrowth. With the exception of AgNPs/Fe3O4/GC-5 h, the AgNPs-containing composites exhibit remarkable power output and coulombic efficiency through lowering proton transfer resistance and air-cathode biofouling. This study provides a perspective for the practical application of MFCs using these efficient antibacterial ORR catalysts.

  12. The evaluation of iron deficiency and anemia in male blood donors with other related factors

    Directory of Open Access Journals (Sweden)

    Yousefinejad Vahid

    2010-01-01

    Full Text Available Aims and Background: Iron deficiency is one of the most common nutritional disorders worldwide and blood donation may cause iron depletion. Limited studies with large sample size have been done on male donors. The aim of this study is to determine the prevalence of iron deficiency and iron deficiency anemia among male donors in the Kurdistan Organization of Blood Transfusion in Iran. Materials and Methods: This was a cross-sectional study. Sample size was 1184 blood donors selected by systematic random sampling. Hemoglobin, serum iron, serum ferritin, total iron banding capacity (TIBC and transferin saturation were measured in donors. Iron depletion, lack of iron stores, iron deficiency, iron deficiency anemia and anemia were evaluated among them. Data was analyzed with SPSS software and X΂, one-way ANOVA, and LSD test. Results: Iron deficiency, anemia, iron deficiency anemia, iron depletion and lack of iron resources were seen in 2.3, 4.08, 2.14, 22.76 and 4.66 percent respectively. There was a significant relationship of iron deficiency and iron deficiency anemia with instances of donation and interval from last donation (P < 0.05. A significant relationship was seen between iron deficiency and iron deficiency anemia among blood donors with more than ten times blood donation (P < 0.05. Conclusions: This study showed regular male donors require especial attention. Therefore, serum ferritin is recommended as a more adequate index to use for iron deficiency screening and planning purposes for iron supplementation among them.

  13. Relative oral efficacy and acute toxicity of hydroxypyridin-4-one iron chelators in mice

    International Nuclear Information System (INIS)

    Porter, J.B.; Morgan, J.; Hoyes, K.P.; Burke, L.C.; Huehns, E.R.; Hider, R.C.

    1990-01-01

    The relationship between the oral efficacy and the acute toxicity of hydroxypyridin-4-one iron chelators has been investigated to clarify structure-function relationships of these compounds in vivo and to identify compounds with the maximum therapeutic safety margin. By comparing 59Fe excretion following oral or intraperitoneal administration of increasing doses of each chelator to iron-overloaded mice, the most effective compounds have been identified. These have partition coefficients (Kpart) above 0.3 in the iron-free form with a trend of increasing oral efficacy with increasing Kpart values (r = .6). However, this is achieved at a cost of increasing acute toxicity, as shown by a linear correlation between 59Fe excretion increase per unit dose and 1/LD50 (r = .83). A sharp increase in the LD50 values is observed for compounds with Kpart values above 1.0, suggesting that such compounds are unlikely to possess a sufficient therapeutic safety margin. Below a Kpart of 1.0, acute toxicity is relatively independent of lipid solubility. All the compounds are less toxic by the oral route than by the intraperitoneal route, although iron excretion is not significantly different by these two routes. At least five compounds (CP51, CP94, CP93, CP96, and CP21) are more effective orally than the same dose of intraperitoneal desferrioxamine (DFO) (P less than or equal to .02) or orally administered L1(CP20) (P less than or equal to .02)

  14. Sphaerotilus natans, a neutrophilic iron-related filamentous bacterium : mechanisms of uranium scavenging

    International Nuclear Information System (INIS)

    Seder-Colomina, Marina

    2014-01-01

    Heavy metals and radionuclides are present in some ecosystems worldwide due to natural contaminations or anthropogenic activities. The use of microorganisms to restore those polluted ecosystems, a process known as bioremediation, is of increasing interest, especially under near-neutral pH conditions. Iron minerals encrusting neutrophilic iron-related bacteria, especially Bacterio-genic Iron Oxides (BIOS), have a poorly crystalline structure, which in addition to their large surface area and reactivity make them excellent scavengers for inorganic pollutants. In this PhD work we studied the different mechanisms of uranium scavenging by the neutrophilic bacterium Sphaerotilus natans, chosen as a model bacterium for iron-related sheath-forming filamentous microorganisms. S. natans can grow as single cells and filaments. The latter were used to investigate U(VI) bio-sorption and U(VI) sorption onto BIOS. In addition, uranium sorption onto the abiotic analogues of such iron minerals was assessed. In order to use S. natans filaments for U(VI) scavenging, it was necessary to identify factors inducing S. natans filamentation. The influence of oxygen was ascertained by using molecular biology techniques and our results revealed that while saturated oxygen conditions resulted in single cell growth, a moderate oxygen depletion to ∼ 3 mg O 2 .L -1 led to the desired filamentous growth of S. natans. BIOS attached to S. natans filaments as well as the abiotic analogues were analysed by XAS at Fe K-edge. Both materials were identified as amorphous iron(III) phosphates with a small component of Fe(II), with a high reactivity towards scavenging of inorganic pollutants. In addition, EXAFS at the U LIII-edge revealed a common structure for the O shells, while those for P, Fe and C were different for each sorbent. An integrated approach combining experimental techniques and speciation calculations made it possible to describe U(VI) adsorption isotherms by using a surface complexation

  15. Greek “red mud” residue: A study of microwave reductive roasting followed by magnetic separation for a metallic iron recovery process

    Energy Technology Data Exchange (ETDEWEB)

    Samouhos, Michail, E-mail: msamouhos@metal.ntua.gr [School of Mining and Metallurgical Engineering, Laboratory of Metallurgy, National Technical University of Athens, 9, Iroon Polytechniou Street, 157 80 Zografou, Athens (Greece); Taxiarchou, Maria; Tsakiridis, Petros E. [School of Mining and Metallurgical Engineering, Laboratory of Metallurgy, National Technical University of Athens, 9, Iroon Polytechniou Street, 157 80 Zografou, Athens (Greece); Potiriadis, Konstantinos [Greek Atomic Energy Commission (GAEC), Patriarxou Grigoriou and Neapoleos, P.O. Box 60092, 15310 Agia Paraskevi, Athens (Greece)

    2013-06-15

    Highlights: • Microwave reduction of a red mud. •Measurement of real and imaginary permittivity of red mud–lignite mixture. •Red mud was subjected to reductive roasting and magnetic separation processes. •The optimum concentrate contains 31.6% iron with a 69.3% metallization degree. •{sup 226}Ra, {sup 228}Ra, {sup 238}U, {sup 228}Th, {sup 232}Th, {sup 40}K were detected in the magnetic concentrate. -- Abstract: The present research work is focused on the development of an alternative microwave reductive roasting process of red mud using lignite (30.15 wt.% C{sub fix}), followed by wet magnetic separation, in order to produce a raw material suitable for sponge or cast iron production. The reduction degree of iron was controlled by both the reductive agent content and the microwave heating time. The reduction followed the Fe{sub 2}O{sub 3} → Fe{sub 3}O{sub 4} → FeO → Fe sequence. The dielectric constants [real (ε′) and imaginary (ε″) permittivities] of red mud–lignite mixture were determined at 2.45 GHz, in the temperature range of 25–1100 °C. The effect of parameters such as temperature, intensity of reducing conditions, intensity of magnetic field and dispersing agent addition rate on the result of both processes was investigated. The phase's transformations in reduction process with microwave heating were determined by X-ray diffraction analysis (XRD) in combination with thermogravimetric/differential thermal analysis (TGA/DTA). The microstructural and morphological characterization of the produced calcines was carried out by scanning electron microscopy (SEM). At the optimum conditions a magnetic concentrate with total iron concentration of 35.15 and 69.3 wt.% metallization degree was obtained.

  16. High strength, biodegradable and cytocompatible alpha tricalcium phosphate-iron composites for temporal reduction of bone fractures.

    Science.gov (United States)

    Montufar, E B; Casas-Luna, M; Horynová, M; Tkachenko, S; Fohlerová, Z; Diaz-de-la-Torre, S; Dvořák, K; Čelko, L; Kaiser, J

    2018-04-01

    In this work alpha tricalcium phosphate (α-TCP)/iron (Fe) composites were developed as a new family of biodegradable, load-bearing and cytocompatible materials. The composites with composition from pure ceramic to pure metallic samples were consolidated by pulsed electric current assisted sintering to minimise processing time and temperature while improving their mechanical performance. The mechanical strength of the composites was increased and controlled with the Fe content, passing from brittle to ductile failure. In particular, the addition of 25 vol% of Fe produced a ceramic matrix composite with elastic modulus much closer to cortical bone than that of titanium or biodegradable magnesium alloys and specific compressive strength above that of stainless steel, chromium-cobalt alloys and pure titanium, currently used in clinic for internal fracture fixation. All the composites studied exhibited higher degradation rate than their individual components, presenting values around 200 μm/year, but also their compressive strength did not show a significant reduction in the period required for bone fracture consolidation. Composites showed preferential degradation of α-TCP areas rather than β-TCP areas, suggesting that α-TCP can produce composites with higher degradation rate. The composites were cytocompatible both in indirect and direct contact with bone cells. Osteoblast-like cells attached and spread on the surface of the composites, presenting proliferation rate similar to cells on tissue culture-grade polystyrene and they showed alkaline phosphatase activity. Therefore, this new family of composites is a potential alternative to produce implants for temporal reduction of bone fractures. Biodegradable alpha-tricalcium phosphate/iron (α-TCP/Fe) composites are promising candidates for the fabrication of temporal osteosynthesis devices. Similar to biodegradable metals, these composites can avoid implant removal after bone fracture healing, particularly in

  17. Single Atomic Iron Catalysts for Oxygen Reduction in Acidic Media: Particle Size Control and Thermal Activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hanguang; Hwang, Sooyeon; Wang, Maoyu; Feng, Zhenxing; Karakalos, Stavros; Luo, Langli; Qiao, Zhi; Xie, Xiaohong; Wang, Chongmin; Su, Dong; Shao, Yuyan; Wu, Gang (BNL); (Oregon State U.); (SC); (PNNL); (Buffalo)

    2017-09-26

    It remains a grand challenge to replace platinum group metal (PGM) catalysts with earth-abundant materials for the oxygen reduction reaction (ORR) in acidic media, which is crucial for large-scale deployment of proton exchange membrane fuel cells (PEMFCs). Here, we report a high-performance atomic Fe catalyst derived from chemically Fe-doped zeolitic imidazolate frameworks (ZIFs) by directly bonding Fe ions to imidazolate ligands within 3D frameworks. Although the ZIF was identified as a promising precursor, the new synthetic chemistry enables the creation of well-dispersed atomic Fe sites embedded into porous carbon without the formation of aggregates. The size of catalyst particles is tunable through synthesizing Fe-doped ZIF nanocrystal precursors in a wide range from 20 to 1000 nm followed by one-step thermal activation. Similar to Pt nanoparticles, the unique size control without altering chemical properties afforded by this approach is able to increase the number of PGM-free active sites. The best ORR activity is measured with the catalyst at a size of 50 nm. Further size reduction to 20 nm leads to significant particle agglomeration, thus decreasing the activity. Using the homogeneous atomic Fe model catalysts, we elucidated the active site formation process through correlating measured ORR activity with the change of chemical bonds in precursors during thermal activation up to 1100 °C. The critical temperature to form active sites is 800 °C, which is associated with a new Fe species with a reduced oxidation number (from Fe3+ to Fe2+) likely bonded with pyridinic N (FeN4) embedded into the carbon planes. Further increasing the temperature leads to continuously enhanced activity, linked to the rise of graphitic N and Fe–N species. The new atomic Fe catalyst has achieved respectable ORR activity in challenging acidic media (0.5 M H2SO4), showing a half-wave potential of 0.85 V vs RHE and leaving only a 30 mV gap with Pt/C (60 μgPt/cm2). Enhanced stability

  18. Ordered hierarchically porous carbon codoped with iron and nitrogen as electrocatalyst for the oxygen reduction reaction.

    Science.gov (United States)

    Deng, Chengwei; Zhong, Hexiang; Yao, Lan; Liu, Sisi; Xu, Zhuang; Zhang, Huamin

    2014-12-01

    N-doped carbon catalysts have attracted great attention as potential alternatives to expensive Pt-based catalysts used in fuel cells. Herein, an ordered hierarchically porous carbon codoped with N and Fe (Fe-NOHPC) is prepared by an evaporation-induced self-assembly process followed by carbonization under ammonia. The soft template and Fe species promote the formation of the porous structure and facilitate the oxygen reduction reaction (ORR).The catalyst possesses an ordered hierarchically porous structure with a large surface area (1172.5 m(2) g(-1) ) and pore volume of 1.03 cm(3) g(-1) . Compared to commercial 20% Pt/C, it exhibits better ORR catalytic activity and higher stability as well as higher methanol tolerance in an alkaline electrolyte, which demonstrates its potential use in fuel cells as a nonprecious cathode catalyst. The N configuration, Fe species, and pore structure of the catalysts are believed to correlate with its high catalytic activity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Greenhouse Gas Mitigation Options in ISEEM Global Energy Model: 2010-2050 Scenario Analysis for Least-Cost Carbon Reduction in Iron and Steel Sector

    Energy Technology Data Exchange (ETDEWEB)

    Karali, Nihan; Xu, Tengfang; Sathaye, Jayant

    2013-12-01

    The goal of the modeling work carried out in this project was to quantify long-term scenarios for the future emission reduction potentials in the iron and steel sector. The main focus of the project is to examine the impacts of carbon reduction options in the U.S. iron and steel sector under a set of selected scenarios. In order to advance the understanding of carbon emission reduction potential on the national and global scales, and to evaluate the regional impacts of potential U.S. mitigation strategies (e.g., commodity and carbon trading), we also included and examined the carbon reduction scenarios in China’s and India’s iron and steel sectors in this project. For this purpose, a new bottom-up energy modeling framework, the Industrial Sector Energy Efficiency Modeling (ISEEM), (Karali et al. 2012) was used to provide detailed annual projections starting from 2010 through 2050. We used the ISEEM modeling framework to carry out detailed analysis, on a country-by-country basis, for the U.S., China’s, and India’s iron and steel sectors. The ISEEM model applicable to iron and steel section, called ISEEM-IS, is developed to estimate and evaluate carbon emissions scenarios under several alternative mitigation options - including policies (e.g., carbon caps), commodity trading, and carbon trading. The projections will help us to better understand emission reduction potentials with technological and economic implications. The database for input of ISEEM-IS model consists of data and information compiled from various resources such as World Steel Association (WSA), the U.S. Geological Survey (USGS), China Steel Year Books, India Bureau of Mines (IBM), Energy Information Administration (EIA), and recent LBNL studies on bottom-up techno-economic analysis of energy efficiency measures in the iron and steel sector of the U.S., China, and India, including long-term steel production in China. In the ISEEM-IS model, production technology and manufacturing details are

  20. Silencing of Iron and Heme-Related Genes Revealed a Paramount Role of Iron in the Physiology of the Hematophagous Vector Rhodnius prolixus

    Directory of Open Access Journals (Sweden)

    Ana B. Walter-Nuno

    2018-02-01

    Full Text Available Iron is an essential element for most organisms However, free iron and heme, its complex with protoporphyrin IX, can be extremely cytotoxic, due to the production of reactive oxygen species, eventually leading to oxidative stress. Thus, eukaryotic cells control iron availability by regulating its transport, storage and excretion as well as the biosynthesis and degradation of heme. In the genome of Rhodnius prolixus, the vector of Chagas disease, we identified 36 genes related to iron and heme metabolism We performed a comprehensive analysis of these genes, including identification of homologous genes described in other insect genomes. We observed that blood-meal modulates the expression of ferritin, Iron Responsive protein (IRP, Heme Oxygenase (HO and the heme exporter Feline Leukemia Virus C Receptor (FLVCR, components of major pathways involved in the regulation of iron and heme metabolism, particularly in the posterior midgut (PM, where an intense release of free heme occurs during the course of digestion. Knockdown of these genes impacted the survival of nymphs and adults, as well as molting, oogenesis and embryogenesis at different rates and time-courses. The silencing of FLVCR caused the highest levels of mortality in nymphs and adults and reduced nymph molting. The oogenesis was mildly affected by the diminished expression of all of the genes whereas embryogenesis was dramatically impaired by the knockdown of ferritin expression. Furthermore, an intense production of ROS in the midgut of blood-fed insects occurs when the expression of ferritin, but not HO, was inhibited. In this manner, the degradation of dietary heme inside the enterocytes may represent an oxidative challenge that is counteracted by ferritins, conferring to this protein a major antioxidant role. Taken together these results demonstrate that the regulation of iron and heme metabolism is of paramount importance for R. prolixus physiology and imbalances in the levels of

  1. Optimization and modeling of reduction of wastewater sludge water content and turbidity removal using magnetic iron oxide nanoparticles (MION).

    Science.gov (United States)

    Hwang, Jeong-Ha; Han, Dong-Woo

    2015-01-01

    Economic and rapid reduction of sludge water content in sewage wastewater is difficult and requires special advanced treatment technologies. This study focused on optimizing and modeling decreased sludge water content (Y1) and removing turbidity (Y2) with magnetic iron oxide nanoparticles (Fe3O4, MION) using a central composite design (CCD) and response surface methodology (RSM). CCD and RSM were applied to evaluate and optimize the interactive effects of mixing time (X1) and MION concentration (X2) on chemical flocculent performance. The results show that the optimum conditions were 14.1 min and 22.1 mg L(-1) for response Y1 and 16.8 min and 8.85 mg L(-1) for response Y2, respectively. The two responses were obtained experimentally under this optimal scheme and fit the model predictions well (R(2) = 97.2% for Y1 and R(2) = 96.9% for Y2). A 90.8% decrease in sludge water content and turbidity removal of 29.4% were demonstrated. These results confirm that the statistical models were reliable, and that the magnetic flocculation conditions for decreasing sludge water content and removing turbidity from sewage wastewater were appropriate. The results reveal that MION are efficient for rapid separation and are a suitable alterative to sediment sludge during the wastewater treatment process.

  2. Graphene oxide nanoplatforms to enhance catalytic performance of iron phthalocyanine for oxygen reduction reaction in bioelectrochemical systems

    Science.gov (United States)

    Costa de Oliveira, Maida Aysla; Mecheri, Barbara; D'Epifanio, Alessandra; Placidi, Ernesto; Arciprete, Fabrizio; Valentini, Federica; Perandini, Alessando; Valentini, Veronica; Licoccia, Silvia

    2017-07-01

    We report the development of electrocatalysts based on iron phthalocyanine (FePc) supported on graphene oxide (GO), obtained by electrochemical oxidation of graphite in aqueous solution of LiCl, LiClO4, and NaClO4. Structure, surface chemistry, morphology, and thermal stability of the prepared materials were investigated by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, atomic force microscopy (AFM), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The catalytic activity toward oxygen reduction reaction (ORR) at neutral pH was evaluated by cyclic voltammetry. The experimental results demonstrate that the oxidation degree of GO supports affects the overall catalytic activity of FePc/GO, due to a modulation effect of the interaction between FePc and the basal plane of GO. On the basis of electrochemical, spectroscopic, and morphological investigations, FePc/GO_LiCl was selected to be assembled at the cathode side of a microbial fuel cell prototype, demonstrating a good electrochemical performance in terms of voltage and power generation.

  3. Moessbauer study of dissimilatory reduction of iron contained in glauconite by alkaliphilic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Chistyakova, Nataliya I., E-mail: nchistyakova@yandex.ru; Rusakov, Vyacheslav S.; Shapkin, Alexey A. [M.V. Lomonosov Moscow State University, Faculty of Physics (Russian Federation); Zhilina, Tatyana N.; Zavarzina, Darya G. [Russian Academy of Sciences, Winogradsky Institute of Microbiology (Russian Federation)

    2012-03-15

    {sup 57}Fe Moessbauer investigations of glauconite and new solid phases formed during the process of the bacterial growth in alkaline environment were carried out at room temperature, 78 K and 4.8 K. The magnetically ordered phase formed during bioleaching of glauconite by G. ferrihydriticus in pure culture or in combination with Cl. alkalicellulosi represented as a mixture of off-stoichiometric magnetite and maghemite. In case of combined binary bacterium culture growth the relative content of magnetically ordered phase was more than for the G. ferrihydriticus growth.

  4. Mössbauer study of dissimilatory reduction of iron contained in glauconite by alkaliphilic bacteria

    International Nuclear Information System (INIS)

    Chistyakova, Nataliya I.; Rusakov, Vyacheslav S.; Shapkin, Alexey A.; Zhilina, Tatyana N.; Zavarzina, Darya G.

    2012-01-01

    57 Fe Mössbauer investigations of glauconite and new solid phases formed during the process of the bacterial growth in alkaline environment were carried out at room temperature, 78 K and 4.8 K. The magnetically ordered phase formed during bioleaching of glauconite by G. ferrihydriticus in pure culture or in combination with Cl. alkalicellulosi represented as a mixture of off-stoichiometric magnetite and maghemite. In case of combined binary bacterium culture growth the relative content of magnetically ordered phase was more than for the G. ferrihydriticus growth.

  5. Compacted graphite iron: Cast iron makes a comeback

    Science.gov (United States)

    Dawson, S.

    1994-08-01

    Although compacted graphite iron has been known for more than four decades, the absence of a reliable mass-production technique has resulted in relatively little effort to exploit its operational benefits. However, a proven on-line process control technology developed by SinterCast allows for series production of complex components in high-quality CGI. The improved mechanical properties of compacted graphite iron relative to conventional gray iron allow for substantial weight reduction in gasoline and diesel engines or substantial increases in horsepower, or an optimal combination of both. Concurrent with these primary benefits, CGI also provides significant emissions and fuel efficiency benefits allowing automakers to meet legislated performance standards. The operational and environmental benefits of compacted graphite iron together with its low cost and recyclability reinforce cast iron as a prime engineering material for the future.

  6. Selective recovery of nickel over iron from a nickel-iron solution using microbial sulfate reduction in a gas-lift bioreactor

    NARCIS (Netherlands)

    Bijmans, M.F.M.; Helvoort, van P.J.; Dar, S.; Dopson, M.; Lens, P.N.L.; Buisman, C.J.N.

    2009-01-01

    Process streams with high concentrations of metals and sulfate are characteristic for the mining and metallurgical industries. This study aims to selectively recover nickel from a nickel-iron-containing solution at pH 5.0 using a single stage bioreactor that simultaneously combines low pH sulfate

  7. Inhibition of nitrate reduction by NaCl adsorption on a nano-zero-valent iron surface during a concentrate treatment for water reuse.

    Science.gov (United States)

    Hwang, Yuhoon; Kim, Dogun; Shin, Hang-Sik

    2015-01-01

    Nanoscale zero-valent iron (NZVI) has been considered as a possible material to treat water and wastewater. However, it is necessary to verify the effect of the matrix components in different types of target water. In this study, different effects depending on the sodium chloride (NaCl) concentration on reductions of nitrates and on the characteristics of NZVI were investigated. Although NaCl is known as a promoter of iron corrosion, a high concentration of NaCl (>3 g/L) has a significant inhibition effect on the degree of NZVI reactivity towards nitrate. The experimental results were interpreted by a Langmuir-Hinshelwood-Hougen-Watson reaction in terms of inhibition, and the decreased NZVI reactivity could be explained by the increase in the inhibition constant. As a result of a chloride concentration analysis, it was verified that 7.7-26.5% of chloride was adsorbed onto the surface of NZVI. Moreover, the change of the iron corrosion product under different NaCl concentrations was investigated by a surface analysis of spent NZVI. Magnetite was the main product, with a low NaCl concentration (0.5 g/L), whereas amorphous iron hydroxide was observed at a high concentration (12 g/L). Though the surface was changed to permeable iron hydroxide, the Fe(0) in the core was not completely oxidized. Therefore, the inhibition effect of NaCl could be explained as the competitive adsorption of chloride and nitrate.

  8. MicroRNA-related genetic variants in iron regulatory genes, dietary iron intake, microRNAs and lung cancer risk.

    Science.gov (United States)

    Zhang, L; Ye, Y; Tu, H; Hildebrandt, M A; Zhao, L; Heymach, J V; Roth, J A; Wu, X

    2017-05-01

    Genetic variations in MicroRNA (miRNA) binding sites may alter structural accessibility of miRNA binding sites to modulate risk of cancer. This large-scale integrative multistage study was aimed to evaluate the interplay of genetic variations in miRNA binding sites of iron regulatory pathway, dietary iron intake and lung cancer (LC) risk. The interplay of genetic variant, dietary iron intake and LC risk was assessed in large-scale case-control study. Functional characterization of the validated SNP and analysis of target miRNAs were performed. We found that the miRNA binding site SNP rs1062980 in 3' UTR of Iron-Responsive Element Binding protein 2 gene (IREB2) was associated with a 14% reduced LC risk (P value = 4.9×10 - 9). Comparing to AA genotype, GG genotype was associated with a 27% reduced LC risk. This association was evident in males and ever-smokers but not in females and never-smokers. Higher level of dietary iron intake was significantly associated with 39% reduced LC risk (P value = 2.0×10 - 8). This association was only present in individuals with AG + AA genotypes with a 46% reduced risk (P value = 1.0×10 - 10), but not in GG genotype. The eQTL-analysis showed that rs1062980 significantly alters IREB2 expression level. Rs1062980 is predicted to alter a miR-29 binding site on IREB2 and indeed the expression of miR-29 is inversely correlated with IREB2 expression. Further, we found that higher circulating miR-29a level was significantly associated with 78% increased LC risk. The miRNA binding site SNP rs1062980 in iron regulatory pathway, which may alter the expression of IREB2 potentially through modulating the binding of miR-29a, together with dietary iron intake may modify risk of LC both individually and jointly. These discoveries reveal novel pathway for understanding lung cancer tumorigenesis and risk stratification. © The Author 2017. Published by Oxford University Press on behalf of the European Society for

  9. Functionalization of multi-walled carbon nanotubes with iron phthalocyanine via a liquid chemical reaction for oxygen reduction in alkaline media

    Science.gov (United States)

    Yan, Xiaomei; Xu, Xiao; Liu, Qin; Guo, Jia; Kang, Longtian; Yao, Jiannian

    2018-06-01

    Iron single-atom catalyst in form of iron-nitrogen-carbon structure possesses the excellent catalytic activity in various chemical reactions. However, exploring a sustainable and stable single-atom metal catalyst still faces a great challenge due to low yield and complicated synthesis. Here, we report a functional multi-wall carbon nanotubes modified with iron phthalocyanine molecules via a liquid chemical reaction and realize the performance of similar single-atom catalysis for oxygen reduction reaction. A serial of characterizations strongly imply the structure change of iron phthalocyanine molecule and its close recombination with multi-wall carbon nanotubes, which are in favor of ORR catalysis. Compared to commercial platinum-carbon catalyst, composites exhibit superior activity for oxygen reduction reaction with higher half-wave potential (0.86 V), lower Tafel slope (38 mV dec-1), higher limiting current density and excellent electrochemical stability. The corresponding Zinc-air battery also presents higher maximum power density and discharge stability. Therefore, these findings provide a facile route to synthesize a highly efficient non-precious metal carbon-based catalyst.

  10. Expression of iron-related genes in human brain and brain tumors

    Directory of Open Access Journals (Sweden)

    Britton Robert S

    2009-04-01

    Full Text Available Abstract Background Defective iron homeostasis may be involved in the development of some diseases within the central nervous system. Although the expression of genes involved in normal iron balance has been intensively studied in other tissues, little is known about their expression in the brain. We investigated the mRNA levels of hepcidin (HAMP, HFE, neogenin (NEO1, transferrin receptor 1 (TFRC, transferrin receptor 2 (TFR2, and hemojuvelin (HFE2 in normal human brain, brain tumors, and astrocytoma cell lines. The specimens included 5 normal brain tissue samples, 4 meningiomas, one medulloblastoma, 3 oligodendrocytic gliomas, 2 oligoastrocytic gliomas, 8 astrocytic gliomas, and 3 astrocytoma cell lines. Results Except for hemojuvelin, all genes studied had detectable levels of mRNA. In most tumor types, the pattern of gene expression was diverse. Notable findings include high expression of transferrin receptor 1 in the hippocampus and medulla oblongata compared to other brain regions, low expression of HFE in normal brain with elevated HFE expression in meningiomas, and absence of hepcidin mRNA in astrocytoma cell lines despite expression in normal brain and tumor specimens. Conclusion These results indicate that several iron-related genes are expressed in normal brain, and that their expression may be dysregulated in brain tumors.

  11. Immobilization of Iron Nanoparticles on Multi Substrates and Its Reduction Removal of Chromium (VI) from Waste Streams

    Science.gov (United States)

    This article describes the in-situ synthesis and immobilization of iron nanoparticles on several substrates at room temperature using NaBH4 as a reducing agent and ascorbic acid as capping agent. The method is very effective in protecting iron nanoparticles from air oxidation for...

  12. Hepcidin-Induced Iron Deficiency Is Related to Transient Anemia and Hypoferremia in Kawasaki Disease Patients

    Science.gov (United States)

    Huang, Ying-Hsien; Kuo, Ho-Chang; Huang, Fu-Chen; Yu, Hong-Ren; Hsieh, Kai-Sheng; Yang, Ya-Ling; Sheen, Jiunn-Ming; Li, Sung-Chou; Kuo, Hsing-Chun

    2016-01-01

    Kawasaki disease (KD) is a type of systemic vasculitis that primarily affects children under the age of five years old. For sufferers of KD, intravenous immunoglobulin (IVIG) has been found to successfully diminish the occurrence of coronary artery lesions. Anemia is commonly found in KD patients, and we have shown that in appropriately elevated hepcidin levels are related to decreased hemoglobin levels in these patients. In this study, we investigated the time period of anemia and iron metabolism during different stages of KD. A total of 100 patients with KD and 20 control subjects were enrolled in this study for red blood cell and hemoglobin analysis. Furthermore, plasma, urine hepcidin, and plasma IL-6 levels were evaluated using enzyme-linked immunosorbent assay in 20 KD patients and controls. Changes in hemoglobin, plasma iron levels, and total iron binding capacity (TIBC) were also measured in patients with KD. Hemoglobin, iron levels, and TIBC were lower (p < 0.001, p = 0.009, and p < 0.001, respectively) while plasma IL-6 and hepcidin levels (both p < 0.001) were higher in patients with KD than in the controls prior to IVIG administration. Moreover, plasma hepcidin levels were positively and significantly correlated with urine hepcidin levels (p < 0.001) prior to IVIG administration. After IVIG treatment, plasma hepcidin and hemoglobin levels significantly decreased (both p < 0.001). Of particular note was a subsequent gradual increase in hemoglobin levels during the three weeks after IVIG treatment; nevertheless, the hemoglobin levels stayed lower in KD patients than in the controls (p = 0.045). These findings provide a longitudinal study of hemoglobin changes and among the first evidence that hepcidin induces transient anemia and hypoferremia during KD’s acute inflammatory phase. PMID:27187366

  13. Hepcidin-Induced Iron Deficiency Is Related to Transient Anemia and Hypoferremia in Kawasaki Disease Patients

    Directory of Open Access Journals (Sweden)

    Ying-Hsien Huang

    2016-05-01

    Full Text Available Kawasaki disease (KD is a type of systemic vasculitis that primarily affects children under the age of five years old. For sufferers of KD, intravenous immunoglobulin (IVIG has been found to successfully diminish the occurrence of coronary artery lesions. Anemia is commonly found in KD patients, and we have shown that in appropriately elevated hepcidin levels are related to decreased hemoglobin levels in these patients. In this study, we investigated the time period of anemia and iron metabolism during different stages of KD. A total of 100 patients with KD and 20 control subjects were enrolled in this study for red blood cell and hemoglobin analysis. Furthermore, plasma, urine hepcidin, and plasma IL-6 levels were evaluated using enzyme-linked immunosorbent assay in 20 KD patients and controls. Changes in hemoglobin, plasma iron levels, and total iron binding capacity (TIBC were also measured in patients with KD. Hemoglobin, iron levels, and TIBC were lower (p < 0.001, p = 0.009, and p < 0.001, respectively while plasma IL-6 and hepcidin levels (both p < 0.001 were higher in patients with KD than in the controls prior to IVIG administration. Moreover, plasma hepcidin levels were positively and significantly correlated with urine hepcidin levels (p < 0.001 prior to IVIG administration. After IVIG treatment, plasma hepcidin and hemoglobin levels significantly decreased (both p < 0.001. Of particular note was a subsequent gradual increase in hemoglobin levels during the three weeks after IVIG treatment; nevertheless, the hemoglobin levels stayed lower in KD patients than in the controls (p = 0.045. These findings provide a longitudinal study of hemoglobin changes and among the first evidence that hepcidin induces transient anemia and hypoferremia during KD’s acute inflammatory phase.

  14. The impact of particle size, relative humidity, and sulfur dioxide on iron solubility in simulated atmospheric marine aerosols.

    Science.gov (United States)

    Cartledge, Benton T; Marcotte, Aurelie R; Herckes, Pierre; Anbar, Ariel D; Majestic, Brian J

    2015-06-16

    Iron is a limiting nutrient in about half of the world's oceans, and its most significant source is atmospheric deposition. To understand the pathways of iron solubilization during atmospheric transport, we exposed size segregated simulated marine aerosols to 5 ppm sulfur dioxide at arid (23 ± 1% relative humidity, RH) and marine (98 ± 1% RH) conditions. Relative iron solubility increased as the particle size decreased for goethite and hematite, while for magnetite, the relative solubility was similar for all of the fine size fractions (2.5-0.25 μm) investigated but higher than the coarse size fraction (10-2.5 μm). Goethite and hematite showed increased solubility at arid RH, but no difference (p > 0.05) was observed between the two humidity levels for magnetite. There was no correlation between iron solubility and exposure to SO2 in any mineral for any size fraction. X-ray absorption near edge structure (XANES) measurements showed no change in iron speciation [Fe(II) and Fe(III)] in any minerals following SO2 exposure. SEM-EDS measurements of SO2-exposed goethite revealed small amounts of sulfur uptake on the samples; however, the incorporated sulfur did not affect iron solubility. Our results show that although sulfur is incorporated into particles via gas-phase processes, changes in iron solubility also depend on other species in the aerosol.

  15. Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids - Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method

    International Nuclear Information System (INIS)

    2004-01-01

    This first edition of ISO 7097-1 together with ISO 7097-2:2004 cancels and replaces ISO 7097:1983, which has been technically revised, and ISO 9989:1996. ISO 7097 consists of the following parts, under the general title Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids: Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method; Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method. This part 2. of ISO 7097 describes procedures for determination of uranium in solutions, uranium hexafluoride and solids. The procedures described in the two independent parts of this International Standard are similar: this part uses a titration with cerium(IV) and ISO 7097-1 uses a titration with potassium dichromate

  16. Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids - Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method

    International Nuclear Information System (INIS)

    2004-01-01

    This first edition of ISO 7097-1 together with ISO 7097-2:2004 cancels and replaces ISO 7097:1983, which has been technically revised, and ISO 9989:1996. ISO 7097 consists of the following parts, under the general title Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids: Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method; Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method. This part 1. of ISO 7097 describes procedures for the determination of uranium in solutions, uranium hexafluoride and solids. The procedures described in the two independent parts of this International Standard are similar: this part uses a titration with potassium dichromate and ISO 7097-2 uses a titration with cerium(IV)

  17. The relative magnitude of the impacts and effects of GHG-related emission reductions

    International Nuclear Information System (INIS)

    Chiotti, Q.; Urquizo, N.

    2000-01-01

    A preliminary assessment of the current knowledge related to the co-benefits associated with climate change mitigation was provided in this document. One of the benefits of the reduction of greenhouse gas emissions is the reduction of other pollutants like sulphur dioxide, nitrogen oxides, carbon monoxide, volatile organic compounds, particulate matter, ground-level ozone, heavy metals and other toxic pollutants. Since these pollutants have an effect on acid deposition, ozone depletion and air quality, the environment, social welfare and human health, this paper provided an initial outline of the complex processes, interactions and uncertainties associated with this issue. Fossil fuels represent the major source of greenhouse gas (GHG) emissions in Canada. The reduction of emissions of GHG could have an impact on the Long Range Transport of air toxic substances, would help increase oxygen concentrations in the Northern Hemisphere, and lead to less carbon monoxide being released in the atmosphere, among others effects. Reductions of GHG emissions would also have an impact on ecosystems by reducing ground-level ozone concentrations. There would be less acid deposition and more dissolved organic carbon, allowing less ultraviolet-B penetration in aquatic ecosystems. In the case of human health, improved air quality impacts on the avoidance of premature mortality and reduced morbidity. Numerous other co-benefits were listed and discussed in this document. The first section stated the purpose and objectives. In section 2, that authors described the science and policy context and discussed building an analytical framework in section 3. The impact of GHG emission reductions on atmospheric pollution and ecosystems was dealt with in section 4 and section 5 was devoted to providing an assessment of the relative magnitude of effects. In section 6, the significance of scope was reviewed, and the authors concluded with section 7 in which they discussed the next steps: phase II

  18. Fabrication of iron-doped cobalt oxide nanocomposite films by electrodeposition and application as electrocatalyst for oxygen reduction reaction

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jingxuan; Wang, Xuemei; Qin, Dongdong; Xue, Zhonghua; Lu, Xiaoquan, E-mail: luxq@nwnu.edu.cn

    2014-11-30

    Highlights: • We fabricated the Fe-doped Co{sub 3}O{sub 4} nanofilms for the first time by potentiostatic electrodeposition method. • The Fe was doped homogeneously in the nanofilms by this method. • Among the different concentration ratios of Co{sup 2+}/Fe{sup 2+}, nanofilm with the ratio of 1:5 exhibits the optimal performance in electrochemical properties assessments. • The Fe-doped Co{sub 3}O{sub 4} nanofilms in this work exhibit good electrocatalytic activity toward oxygen reduction and appear to be promising cathodic electrocatalyst in alkaline fuel cells. - Abstract: In this work, Fe-doped Co{sub 3}O{sub 4} nanofilms were fabricated by electrodeposition on FTO glass substrates for the first time. The structures of the as-prepared nanofilms were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Characterization results demonstrate that Fe was doped homogeneously in the nanofilms. As the different concentration ratios of Fe{sup 2+}/Co{sup 2+} were explored, nanofilm with the ratio of 1:5 exhibits the optimal performance in electrochemical properties assessments. It is considered that the difference in the catalytic activities for the ORR of the samples may be due to the fact that the joining of iron changed the catalyst surface's electric state and enhanced the acidity of cobalt centers, on the other hand, the doping process probably modified the absorption property of the nanofilms. The experimental results suggest that the Fe-doped Co{sub 3}O{sub 4} nanofilms in this work exhibit favorable electrocatalytic activity toward ORR and appear to be promising cathodic electrocatalyst in alkaline fuel cells.

  19. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of a health claim related to iron and maintenance of normal hair growth pursuant to Article 13(5) of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    of a health claim based on newly developed scientific evidence related to iron and maintenance of normal hair growth. Iron is sufficiently characterised. The claimed effect is “reduction of excessive hair loss”. The target population proposed by the applicant is non-menopausal women, aged between 19 and 49...... years, presenting with excessive hair loss. The Panel considers that maintenance of normal hair growth is a beneficial physiological effect. The applicant identified a total of five observational studies and one review as pertinent to the claim. The narrative review contained no primary data. In two...... status and hair loss while a third study showed an association between low iron status and hair loss. In weighing the evidence, the Panel took into account that two observational studies showed no relationship of iron status with hair loss and that one observational study showed an association. The Panel...

  20. Continuous preparation of nanoscale zero-valent iron using impinging stream-rotating packed bed reactor and their application in reduction of nitrobenzene

    Science.gov (United States)

    Jiao, Weizhou; Qin, Yuejiao; Luo, Shuai; Feng, Zhirong; Liu, Youzhi

    2017-02-01

    Nanoscale zero-valent iron (nZVI) was continuously prepared by high-gravity reaction precipitation through a novel impinging stream-rotating packed bed (IS-RPB). Reactant solutions of FeSO4 and NaBH4 were conducted into the IS-RPB with flow rates of 60 L/h and rotating speed of 1000 r/min for the preparation of nZVI. As-prepared nZVI obtained by IS-RPB were quasi-spherical morphology and almost uniformly distributed with a particle size of 10-20 nm. The reactivity of nZVI was estimated by the degradation of 100 ml nitrobenzene (NB) with initial concentration of 250 mg/L. The optimum dosage of nZVI obtained by IS-RPB was 4.0 g/L as the NB could be completely removed within 10 min, which reduced 20% compared with nZVI obtained by stirred tank reactor (STR). The reduction of NB and production of aniline (AN) followed pseudo-first-order kinetics, and the pseudo-first-order rate constants were 0.0147 and 0.0034 s-1, respectively. Furthermore, the as-prepared nZVI using IS-RPB reactor in this work can be used within a relatively wide range pH of 1-9.

  1. Continuous preparation of nanoscale zero-valent iron using impinging stream-rotating packed bed reactor and their application in reduction of nitrobenzene

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Weizhou, E-mail: jwz0306@126.com; Qin, Yuejiao [North University of China, Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering (China); Luo, Shuai [Virginia Polytechnic Institute and State University, Department of Civil and Environmental Engineering (United States); Feng, Zhirong; Liu, Youzhi [North University of China, Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering (China)

    2017-02-15

    Nanoscale zero-valent iron (nZVI) was continuously prepared by high-gravity reaction precipitation through a novel impinging stream-rotating packed bed (IS-RPB). Reactant solutions of FeSO{sub 4} and NaBH{sub 4} were conducted into the IS-RPB with flow rates of 60 L/h and rotating speed of 1000 r/min for the preparation of nZVI. As-prepared nZVI obtained by IS-RPB were quasi-spherical morphology and almost uniformly distributed with a particle size of 10–20 nm. The reactivity of nZVI was estimated by the degradation of 100 ml nitrobenzene (NB) with initial concentration of 250 mg/L. The optimum dosage of nZVI obtained by IS-RPB was 4.0 g/L as the NB could be completely removed within 10 min, which reduced 20% compared with nZVI obtained by stirred tank reactor (STR). The reduction of NB and production of aniline (AN) followed pseudo-first-order kinetics, and the pseudo-first-order rate constants were 0.0147 and 0.0034 s{sup −1}, respectively. Furthermore, the as-prepared nZVI using IS-RPB reactor in this work can be used within a relatively wide range pH of 1–9.

  2. Constraining the role of iron in environmental nitrogen transformations. Dual stable isotope systematics of abiotic NO2- reduction by Fe(II) and its production of N2O

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, David [Harvard Univ., Cambridge, MA (United States); Wankel, Scott David [Woods Hole Oceanographic Inst., MA (United States); Buchwald, Carolyn [Woods Hole Oceanographic Inst., MA (United States); Hansel, Colleen [Woods Hole Oceanographic Inst., MA (United States)

    2015-09-16

    Redox reactions involving nitrogen and iron have been shown to have important implications for mobilization of priority contaminants. Thus, an understanding of the linkages between their biogeochemical cycling is critical for predicting subsurface mobilization of radionuclides such as uranium. Despite mounting evidence for biogeochemical interactions between iron and nitrogen, our understanding of their environmental importance remains limited. Here we present an investigation of abiotic nitrite (NO2-) reduction by Fe(II) or ‘chemodenitrification,’ and its relevance to the production of nitrous oxide (N2O), specifically focusing on dual (N and O) isotope systematics under a variety of environmentally relevant conditions. We observe a range of kinetic isotope effects that are regulated by reaction rates, with faster rates at higher pH (~8), higher concentrations of Fe(II) and in the presence of mineral surfaces. A clear non-linear relationship between rate constant and kinetic isotope effects of NO2- reduction was evident (with larger isotope effects at slower rates) and is interpreted as reflecting the dynamics of Fe(II)-N reaction intermediates. N and O isotopic composition of product N2O also suggests a complex network of parallel and/or competing pathways. Our findings suggest that NO2- reduction by Fe(II) may represent an important abiotic source of environmental N2O, especially in iron-rich environments experiencing dynamic redox variations. This study provides a multi-compound, multi-isotope framework for evaluating the environmental occurrence of abiotic NO2- reduction and N2O formation, helping future studies constrain the relative roles of abiotic and biological N2O production pathways.

  3. Rapid photometric determination of phosphorus in iron ores and related materials as phosphomolybdenum-blue.

    Science.gov (United States)

    Bhargava, O P; Gmitro, M

    1984-04-01

    A rapid, simple and accurate method for determining phosphorus photometrically in iron ores and related materials, obviating the use of perchloric acid, is described. The sample is fused with sodium peroxide in a zirconium crucible and the melt dissolved in hydrochloric acid. The molybdenum-blue complex is developed by the addition of ammonium molybdate and hydrazine sulphate and the absorbance is measured at 725 nm. The range of the method is from 0.005 to 1.0% P. A batch of 6 samples can be analysed in about 2 hr.

  4. Electron-beam-induced reduction of Fe3+ in iron phosphate dihydrate, ferrihydrite, haemosiderin and ferritin as revealed by electron energy-loss spectroscopy

    International Nuclear Information System (INIS)

    Pan, Ying-Hsi; Vaughan, Gareth; Brydson, Rik; Bleloch, Andrew; Gass, Mhairi; Sader, Kasim; Brown, Andy

    2010-01-01

    The effect of high-energy electron irradiation on ferritin/haemosiderin cores (in an iron-overloaded human liver biopsy), its mineral analogue; six-line ferrihydrite (6LFh), and iron phosphate dihydrate (which has similar octahedral ferric iron to oxygen coordination to that in ferrihydrite and ferritin/haemosiderin cores) has been investigated using electron energy-loss spectroscopy (EELS). Fe L 2,3 -ionisation edges were recorded on two types of electron microscope: a 200 keV transmission electron microscope (TEM) and a 100 keV scanning transmission electron microscope (STEM), in order to investigate the damage mechanisms in operation and to establish a methodology for minimum specimen alteration during analytical electron microscopic characterisation. A specimen damage mechanism dominated by radiolysis that results in the preferential loss of iron co-ordinating ligands (O, OH and H 2 O) is discussed. The net result of irradiation is structural re-organisation and reduction of iron within the iron hydroxides. At sufficiently low electron fluence and particularly in the lower incident energy, finer probe diameter STEM, the alteration is shown to be minimal. All the materials examined exhibit damage which as a function of cumulative fluence is best fitted by an inverse power-law, implying that several chemical and structural changes occur in response to the electron beam and we suggest that these are governed by secondary processes arising from the primary ionisation event. This work affirms that electron fluence and current density should be considered when measuring mixed valence ratios with EELS.

  5. Electron-beam-induced reduction of Fe{sup 3+} in iron phosphate dihydrate, ferrihydrite, haemosiderin and ferritin as revealed by electron energy-loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Ying-Hsi; Vaughan, Gareth; Brydson, Rik [Institute for Materials Research, SPEME, University of Leeds, Leeds LS2 9JT (United Kingdom); Bleloch, Andrew; Gass, Mhairi [SuperSTEM, Daresbury Laboratories, Warrington WA4 4AD (United Kingdom); Sader, Kasim [Institute for Materials Research, SPEME, University of Leeds, Leeds LS2 9JT (United Kingdom); SuperSTEM, Daresbury Laboratories, Warrington WA4 4AD (United Kingdom); Brown, Andy, E-mail: a.p.brown@leeds.ac.uk [Institute for Materials Research, SPEME, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2010-07-15

    The effect of high-energy electron irradiation on ferritin/haemosiderin cores (in an iron-overloaded human liver biopsy), its mineral analogue; six-line ferrihydrite (6LFh), and iron phosphate dihydrate (which has similar octahedral ferric iron to oxygen coordination to that in ferrihydrite and ferritin/haemosiderin cores) has been investigated using electron energy-loss spectroscopy (EELS). Fe L{sub 2,3}-ionisation edges were recorded on two types of electron microscope: a 200 keV transmission electron microscope (TEM) and a 100 keV scanning transmission electron microscope (STEM), in order to investigate the damage mechanisms in operation and to establish a methodology for minimum specimen alteration during analytical electron microscopic characterisation. A specimen damage mechanism dominated by radiolysis that results in the preferential loss of iron co-ordinating ligands (O, OH and H{sub 2}O) is discussed. The net result of irradiation is structural re-organisation and reduction of iron within the iron hydroxides. At sufficiently low electron fluence and particularly in the lower incident energy, finer probe diameter STEM, the alteration is shown to be minimal. All the materials examined exhibit damage which as a function of cumulative fluence is best fitted by an inverse power-law, implying that several chemical and structural changes occur in response to the electron beam and we suggest that these are governed by secondary processes arising from the primary ionisation event. This work affirms that electron fluence and current density should be considered when measuring mixed valence ratios with EELS.

  6. Reduction kinetics of Wüstite scale on pure iron and steel sheets in Ar and H

    NARCIS (Netherlands)

    Mao, W.; Sloof, W.G.

    2017-01-01

    A dense and closed Wüstite scale is formed on pure iron and Mn alloyed steel after oxidation in Ar + 33 vol pct CO2 + 17 vol pct CO gas mixture. Reducing the Wüstite scale in Ar + H2 gas mixture forms a dense and uniform iron layer on top of the remaining Wüstite scale,

  7. Microbial reduction of ferric iron oxyhydroxides as a way for remediation of grey forest soils heavily polluted with toxic metals by infiltration of acid mine drainage

    Science.gov (United States)

    Georgiev, Plamen; Groudev, Stoyan; Spasova, Irena; Nicolova, Marina

    2015-04-01

    The abandoned uranium mine Curilo is a permanent source of acid mine drainage (AMD) which steadily contaminated grey forest soils in the area. As a result, the soil pH was highly acidic and the concentration of copper, lead, arsenic, and uranium in the topsoil was higher than the relevant Maximum Admissible Concentration (MAC) for soils. The leaching test revealed that approximately half of each pollutant was presented as a reducible fraction as well as the ferric iron in horizon A was presented mainly as minerals with amorphous structure. So, the approach for remediation of the AMD-affected soils was based on the process of redoxolysis carried out by iron-reducing bacteria. Ferric iron hydroxides reduction and the heavy metals released into soil solutions was studied in the dependence on the source of organic (fresh or silage hay) which was used for growth and activity of soil microflora, initial soil pH (3.65; 4.2; and 5.1), and the ion content of irrigation solutions. The combination of limestone (2.0 g/ kg soil), silage addition (at rate of 45 g dry weight/ kg soil) in the beginning and reiterated at 6 month since the start of soil remediation, and periodical soil irrigation with slightly acidic solutions containing CaCl2 was sufficient the content of lead and arsenic in horizon A to be decreased to concentrations similar to the relevant MAC. The reducible, exchangeable, and carbonate mobile fractions were phases from which the pollutants was leached during the applied soil remediation. It determined the higher reduction of the pollutants bioavailability also as well as the process of ferric iron reduction was combined with neutralization of the soil acidity to pH (H2O) 6.2.

  8. Brain iron accumulation affects myelin-related molecular systems implicated in a rare neurogenetic disease family with neuropsychiatric features.

    Science.gov (United States)

    Heidari, M; Johnstone, D M; Bassett, B; Graham, R M; Chua, A C G; House, M J; Collingwood, J F; Bettencourt, C; Houlden, H; Ryten, M; Olynyk, J K; Trinder, D; Milward, E A

    2016-11-01

    The 'neurodegeneration with brain iron accumulation' (NBIA) disease family entails movement or cognitive impairment, often with psychiatric features. To understand how iron loading affects the brain, we studied mice with disruption of two iron regulatory genes, hemochromatosis (Hfe) and transferrin receptor 2 (Tfr2). Inductively coupled plasma atomic emission spectroscopy demonstrated increased iron in the Hfe -/- × Tfr2 mut brain (P=0.002, n ≥5/group), primarily localized by Perls' staining to myelinated structures. Western immunoblotting showed increases of the iron storage protein ferritin light polypeptide and microarray and real-time reverse transcription-PCR revealed decreased transcript levels (Pgross myelin structure and integrity appear unaffected (P>0.05). Overlap (P0.05). These results implicate myelin-related systems involved in NBIA neuropathogenesis in early responses to iron loading. This may contribute to behavioral symptoms in NBIA and hemochromatosis and is relevant to patients with abnormal iron status and psychiatric disorders involving myelin abnormalities or resistant to conventional treatments.

  9. Relation between serum lipoperoxide concentrations and iron or copper status over one year in Cuban adult men

    Energy Technology Data Exchange (ETDEWEB)

    Arnaud, J.; Renversez, J.C.; Favier, A.E. [Dept. de Biologie Integree, CHUG, Grenoble (France); Fleites, P.; Perez-Cristia, R. [Centro national de Toxicologia (CENATOX), La Habana (Cuba); Chassagne, M.; Barnouin, J. [INRA, Unite d' Ecopathologie, Saint Genes Champanelle (France); Verdura, T. [Inst. Finlay, La Lisa, La Habana (Cuba); Garcia, I.G. [Inst. de Farmacia y Alimentos, La Coronela, La Lisa, Ciudad de la Habana (Cuba); Tressol, J.C. [INRA, Unite maladies metaboliques et micronutriments, Saint Genes Champanelle (France)

    2001-07-01

    The aims of this study were to determine the relations between iron and copper status and lipid peroxidation at different periods over one year in low-income and low-energy intake healthy subjects. The study was conducted in 199 middle-aged healthy Cuban men from March 1995 to February 1996. Iron status was assessed by the determination of serum ferritin, transferrin saturation, whole blood hemoglobin and iron intakes. Copper status was evaluated by the determination of serum copper and copper intakes. Serum thiobarbituric acid substances (TBARS) determination was used as an index of lipid peroxidation. Rank correlations were observed between serum TBARS concentrations and iron or copper status indices at different periods. In period 3 (end of the rainy season), serum TBARS and ferritin concentrations were maximum whereas blood hemoglobin levels and iron intake were minimum. Serum TBARS concentrations were significantly higher than the reference values of the laboratory whereas, iron and copper status were within the reference ranges. These results suggested that iron and copper status may be associated with lipid peroxidation in subjects without metal overloads and that variations over the year needed to be taken in account. (orig.)

  10. Relating black carbon content to reduction of snow albedo

    Science.gov (United States)

    Brandt, R. E.; Warren, S. G.; Clarke, A. D.

    2011-12-01

    In remote snow of the Northern Hemisphere, the levels of soot pollution are in the parts-per-billion (ppb) range, where the effect on albedo is at the level of a few percent. A reduction of albedo by 1-2% is significant for climate but is difficult to detect experimentally, because snow albedo depends on several other variables. In our work to quantify the climatic effect of black carbon (BC) in snow, we therefore do not directly measure the albedo reduction. Instead, we use a two-step procedure: (1) We collect snow samples, melt and filter them, and analyze the filters spectrophotometrically for BC concentration. (2) We use the BC amount from the filter measurement, together with snow grain size, in a radiative transfer model to compute the albedo reduction. Our radiative transfer model uses the discrete ordinates algorithm DISORT 2.0. We have chosen a representative BC size distribution and optical constants, and have incorporated those of mineral dust as well. While a given mass of BC causes over an order of magnitude more snow albedo reduction compared to dust, a snowpack containing dust mutes the albedo-reducing effect of BC. Because the computed reduction of snow albedo is model-based, it requires experimental verification. We doubt that direct measurement of albedo-reduction will be feasible in nature, because of the vertical variation of both snow grain size and soot content, and because the natural soot content is small. We conclude that what is needed is an artificial snowpack, with uniform grain size and large uniform soot content (ppm not ppb), to produce a large signal on albedo. We have chosen to pursue this experiment outdoors rather than in the laboratory, for the following reasons: (1) The snowpack in the field of view is uniformly illuminated if the source of radiation is the Sun. (2) Visible radiation penetrates into the snow, so photons emerge horizontally distant from where they entered. In the limited width of a laboratory snowpack, radiation

  11. Heterojunction nanowires having high activity and stability for the reduction of oxygen: Formation by self-assembly of iron phthalocyanine with single walled carbon nanotubes (FePc/SWNTs)

    KAUST Repository

    Zhu, Jia; Jia, Nana; Yang, Lijun; Su, Dong; Park, Jinseong; Choi, YongMan; Gong, Kuanping

    2014-01-01

    A self-assembly approach to preparing iron phthalocyanine/single-walled carbon nanotube (FePc/SWNT) heterojunction nanowires as a new oxygen reduction reaction (ORR) electrocatalyst has been developed by virtue of water-adjusted dispersing in 1

  12. Niche segregation in two closely related species of stickleback along a physiological axis: explaining multidecadel changes in fish distribution from iron-induced respiratory impairment

    NARCIS (Netherlands)

    Verberk, W.C.E.P.; Munckhof, van den P.J.J.; Pollux, B.J.A.

    2012-01-01

    Acute exposure to iron can be lethal to fish, but long-term sublethal impacts of iron require further study. Here we investigated whether the spatial and temporal distribution (1967–2004) of two closely related species of stickleback matched the spatial distribution of iron concentrations in the

  13. Possible Links Among Iron Reduction, Silicate Weathering, and Arsenic Mobility in the Mississippi River Alluvial Aquifer in Louisiana

    Science.gov (United States)

    Borrok, D. M.; Lenz, R. M.; Jennings, J. E.; Gentry, M. L.; Vinson, D. S.

    2017-12-01

    The Lower Mississippi River Alluvial Aquifer (LMRAA) is a critical groundwater resource for Arkansas, Mississippi, and Louisiana. Part of the aquifer in Louisiana contains waters rich in Na, HCO3, Fe, and As. We hypothesize that CO2 generated from dissimilatory iron reduction (DIR) within the aquifer acts to weather Na-bearing silicates, contributing Na and HCO3, which may influence the mobility of As. We examined the geochemistry of the aquifer using historical and new data collected from the Louisiana Department of Environmental Quality (LDEQ). Major and trace element data were collected from about 25 wells in the LMRAA in Louisiana every three years from 2001-2016. Samples collected in 2016 were additionally analyzed for water isotopes and the δ13C of dissolved inorganic carbon (DIC). Results suggest that groundwater in the LMRAA can be broken into two broad categories, (1) water with a molar Na/Cl ratio near 1 and/or high salinity, and (2) water with excess Na (i.e., the molar concentration of Na is greater than that of Cl) that is often higher in alkalinity (up to 616 mg/L as CaCO3), Fe (up to 21 mg/L), and sometimes As (up to 67 µg/L). Concentrations of dissolved Fe were found to correlate, at least weakly, with alkalinity and Na excess. Six of the approximately 25 wells historically sampled consistently had concentrations of As >10 µg/L. These locations generally correspond with groundwater characterized by higher Fe, alkalinity, and Na-excess. Initial results for δD and δ18O suggest that more isotopically depleted waters are sourced from the Mississippi River, whereas local precipitation recharges the aquifer farther from the river (δ18O ranged from -7.5‰ to -3.5‰). Part of the δ13C-DIC variation (-17.4‰ to -10.6‰) is consistent with pH modification (6.5-7.7) along differing horizontal and vertical flow paths in the aquifer. This geochemistry appears to be controlled in part by geology. Areas nearer to the current Mississippi River where

  14. Performance of nanoscale zero-valent iron in nitrate reduction from water using a laboratory-scale continuous-flow system.

    Science.gov (United States)

    Khalil, Ahmed M E; Eljamal, Osama; Saha, Bidyut Baran; Matsunaga, Nobuhiro

    2018-04-01

    Nanoscale zero-valent iron (nZVI) is a versatile treatment reagent that should be utilized in an effective application for nitrate remediation in water. For this purpose, a laboratory-scale continuous-flow system (LSCFS) was developed to evaluate nZVI performance in removal of nitrate in different contaminated-water bodies. The equipment design (reactor, settler, and polisher) and operational parameters of the LSCFS were determined based on nZVI characterization and nitrate reduction kinetics. Ten experimental runs were conducted at different dosages (6, 10 and 20 g) of nZVI-based reagents (nZVI, bimetallic nZVI-Cu, CuCl 2 -added nZVI). Effluent concentrations of nitrogen and iron compounds were measured, and pH and ORP values were monitored. The major role exhibited by the recirculation process of unreacted nZVI from the settler to the reactor succeeded in achieving overall nitrate removal efficiency (RE) of >90%. The similar performance of both nZVI and copper-ions-modified nZVI in contaminated distilled water was an indication of LSCFS reliability in completely utilizing iron nanoparticles. In case of treating contaminated river water and simulated groundwater, the nitrate reduction process was sensitive towards the presence of interfering substances that dropped the overall RE drastically. However, the addition of copper ions during the treatment counteracted the retardation effect and greatly enhanced the nitrate RE. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Classic Maya civilization collapse related to modest reduction in precipitation

    Science.gov (United States)

    Medina-Elizalde, M.; Rohling, E. J.

    2013-05-01

    The disintegration of the Classic Maya civilization during the Terminal Classic Period (TCP) in the Yucatán Peninsula (YP) and Central America was a complex process that occurred over a ~200-year interval and involved a catastrophic depopulation of the region. While it is well established that the civilization collapse coincided with widespread episodes of drought, their nature and severity remain enigmatic. We present a quantitative analysis that offers a coherent interpretation for four of the most detailed paleoclimate records of the event. The underlying processes driving the patterns and amplitudes of these environmental records during the TCP are evaluated with an isotope mass balance model set up for Lake Chichancanab, located in the YP. We use our hydrological-isotope model (i) to test whether the TCP droughts reflect a persistent summer season southern shift of the intertropical convergence zone and its associated belt of convective activity, away from the YP, and (2) to simulate the development of Lake Chichancanab as a function of weaker perturbations to summer precipitation as reflected by a stalagmite d18O-derived rainfall record from the YP. We conclude that the droughts occurring during the disintegration of the Maya civilization represented up to 40% reduction in annual precipitation, likely due to a reduction in summer season tropical cyclone frequency/intensity. Archaeological and Paleoclimatic records from the Yucatan Peninsula

  16. Iron based superconductors and related compounds synthesized by solid state metathesis and high temperature reactions

    International Nuclear Information System (INIS)

    Frankovsky, Rainer

    2013-01-01

    The results of this thesis can be divided into three major topics, which can also be seen as different approaches of solid state chemistry to reveal interesting features of known and unknown compounds and to develop alternative synthesis routes. Firstly, known compounds with related structural motifs to the superconducting iron-arsenides were investigated regarding their structural and physical properties. In case of La 3 Pd 4 Ge 4 the influence of Fe doping on the properties was studied, whereas in the series ZrMAs (M=Ti,V) the physical properties have not yet been reported at all and were investigated for the first time. Secondly, an alternative synthesis route has been developed for the synthesis of superconducting LaFeAsO 1-x F x . This solid state metathesis reaction distinctly increased the quality of the samples compared to conventionally prepared products. Furthermore, the reaction pathway was investigated and clarified, which helps to understand the processes during high temperature solid state metathesis reactions in general. Thirdly, this alternative synthesis route was expanded to other systems and new compounds like co-substituted LaFe 1-x Mn x AsO 1-y F y were prepared and thoroughly investigated. This led to a complex study of the interplay of magnetism, electronic and structural conditions and the occurrence of superconducting properties. The investigation and understanding of such complex coherences will probably be decisive for the further understanding of the superconducting mechanism in iron based superconductors.

  17. Reduction and Immobilization of Radionuclides and Toxic Metal Ions Using Combined Zero Valent Iron and Anaerobic Bacteria

    International Nuclear Information System (INIS)

    Weathers, Lenly J.; Katz, Lynn E.

    2002-01-01

    The use of zero valent iron, permeable reactive barriers (PRBs) for groundwater remediation continues to increase. AN exciting variation of this technology involves introducing anaerobic bacteria into these barriers so that both biological and abiotic pollutant removal processes are functional. This work evaluated the hypothesis that a system combining a mixed culture of sulfate reducing bacteria (SRB) with zero valent iron would have a greater cr(VI) removal efficiency and a greater total Cr(VI) removal capacity than a zero valent iron system without the microorganisms. Hence, the overall goal of this research was to compare the performance of these types of systems with regard to their Cr(VI) removal efficiency and total Cr(VI) removal capacity. Both batch and continuous flow reactor systems were evaluated

  18. Reduction and Immobilization of Radionuclides and Toxic Metal Ions Using Combined Zero Valent Iron and Anaerobic Bacteria; FINAL

    International Nuclear Information System (INIS)

    Lenly J. Weathers; Lynn E. Katz

    2002-01-01

    The use of zero valent iron, permeable reactive barriers (PRBs) for groundwater remediation continues to increase. AN exciting variation of this technology involves introducing anaerobic bacteria into these barriers so that both biological and abiotic pollutant removal processes are functional. This work evaluated the hypothesis that a system combining a mixed culture of sulfate reducing bacteria (SRB) with zero valent iron would have a greater cr(VI) removal efficiency and a greater total Cr(VI) removal capacity than a zero valent iron system without the microorganisms. Hence, the overall goal of this research was to compare the performance of these types of systems with regard to their Cr(VI) removal efficiency and total Cr(VI) removal capacity. Both batch and continuous flow reactor systems were evaluated

  19. Reduction and Immobilization of Radionuclides and Toxic Metal Ions Using Combined Zero Valent Iron and Anaerobic Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Lenly J. Weathers; Lynn E. Katz

    2002-05-29

    The use of zero valent iron, permeable reactive barriers (PRBs) for groundwater remediation continues to increase. AN exciting variation of this technology involves introducing anaerobic bacteria into these barriers so that both biological and abiotic pollutant removal processes are functional. This work evaluated the hypothesis that a system combining a mixed culture of sulfate reducing bacteria (SRB) with zero valent iron would have a greater cr(VI) removal efficiency and a greater total Cr(VI) removal capacity than a zero valent iron system without the microorganisms. Hence, the overall goal of this research was to compare the performance of these types of systems with regard to their Cr(VI) removal efficiency and total Cr(VI) removal capacity. Both batch and continuous flow reactor systems were evaluated.

  20. Intersections of pathways involving biotin and iron relative to therapeutic mechanisms for progressive multiple sclerosis.

    Science.gov (United States)

    Heidker, Rebecca M; Emerson, Mitchell R; LeVine, Steven M

    2016-12-01

    While there are a variety of therapies for relapsing remitting multiple sclerosis (MS), there is a lack of treatments for progressive MS. An early study indicated that high dose biotin therapy has beneficial effects in approximately 12-15% of patients with progressive MS. The mechanisms behind the putative improvements seen with biotin therapy are not well understood, but have been postulated to include: 1) improving mitochondrial function which is impaired in MS, 2) increasing synthesis of lipids and cholesterol to facilitate remyelination, and 3) affecting gene expression. We suggest one reason that a greater percentage of patients with MS didn't respond to biotin therapy is the inaccessibility or lack of other nutrients, such as iron. In addition to biotin, iron (or heme) is necessary for energy production, biosynthesis of cholesterol and lipids, and for some protective mechanisms. Both biotin and iron are required for myelination during development, and by inference, remyelination. However, iron can also play a role in the pathology of MS. Increased deposition of iron can occur in some CNS structures possibly promoting oxidative damage while low iron levels can occur in other areas. Thus, the potential, detrimental effects of iron need to be considered together with the need for iron to support metabolic demands associated with repair and/or protective processes. We propose the optimal utilization of iron may be necessary to maximize the beneficial effects of biotin. This review will examine the interactions between biotin and iron in pathways that may have therapeutic or pathogenic implications for MS.

  1. 2-Nitrophenol reduction promoted by S. putrefaciens 200 and biogenic ferrous iron: The role of different size-fractions of dissolved organic matter

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Zhenke [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Tao, Liang, E-mail: taoliang@soil.gd.cn [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Li, Fangbai, E-mail: cefbli@soil.gd.cn [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China)

    2014-08-30

    Graphical abstract: - Highlights: • Dissolved organic matter (DOM) act as electron shuttle in redox reactions. • Different molecular weight DOM fractions have different electron transfer capacity. • A higher electron transfer capacities value indicates a higher reduction rate. • DOM transfer electron from S. putrefaciens 200 to 2-nitrophenol (2-NP) and Fe(III). • DOM and biogenic Fe(II) synergistically enhanced the 2-NP reductive transformation. - Abstract: The reduction of nitroaromatic compounds (listed as a priority pollutant) in natural subsurface environments typically coexists with dissimilatory reduction of iron oxides effected by dissolved organic matter (DOM). Investigating the impact of the DOM that influences those reduction processes is crucial for understanding and predicting the geochemical fate of these environmental species. This study investigated the impact of different molecular weight DOM fractions (DMWDs) on the 2-nitrophenol (2-NP) reduction by S. putrefaciens 200 (SP200) and α-Fe{sub 2}O{sub 3} with lactate (excluding electron donor interference). Kinetic measurements demonstrated that 2-NP reduction rates were affected by the redox reactivity of active species under DMWDs (denoted as L-DOM, M-DOM, and H-DOM). The enhanced reduction rates are consistent with the negative shifts in peak oxidation potential values, the increases in HA-like/FA-like values, aromaticity index values and electron transfer capacity values. L-DOM acted mainly as ligands to complex Fe(II), whereas the significant role of H-DOM in reductive reactions should be acting as an electron shuttle, transferring electrons from SP200 to Fe(III) and 2-NP and from biogenic Fe(II) to 2-NP, further accelerating the 2-NP reductions. Those observations provide valuable insights into the role of DOM in the biogeochemical redox processes and the remediation of contaminated soil in a natural environment.

  2. Relative Error Model Reduction via Time-Weighted Balanced Stochastic Singular Perturbation

    DEFF Research Database (Denmark)

    Tahavori, Maryamsadat; Shaker, Hamid Reza

    2012-01-01

    A new mixed method for relative error model reduction of linear time invariant (LTI) systems is proposed in this paper. This order reduction technique is mainly based upon time-weighted balanced stochastic model reduction method and singular perturbation model reduction technique. Compared...... by using the concept and properties of the reciprocal systems. The results are further illustrated by two practical numerical examples: a model of CD player and a model of the atmospheric storm track....

  3. Common pitfalls in statistical analysis: Absolute risk reduction, relative risk reduction, and number needed to treat

    Science.gov (United States)

    Ranganathan, Priya; Pramesh, C. S.; Aggarwal, Rakesh

    2016-01-01

    In the previous article in this series on common pitfalls in statistical analysis, we looked at the difference between risk and odds. Risk, which refers to the probability of occurrence of an event or outcome, can be defined in absolute or relative terms. Understanding what these measures represent is essential for the accurate interpretation of study results. PMID:26952180

  4. Thiosulfate and sulfite distributions in porewater of marine sediments related to manganese, iron, and sulfur geochemistry

    Science.gov (United States)

    Thamdrup, Bo; Finster, Kai; Fossing, Henrik; Hansen, Jens Würgler; Jørgensen, Bo Barker

    1994-01-01

    Depth distributions of thiosulfate (S 2O 32-) and sulfite (SO 32-) were measured in the porewaters of a Danish salt marsh and subtidal marine sediments by HPLC analysis after derivatization with DTNP [2,2'-dithiobis(5-nitropyridine)]. The distributions were compared to the redox zonation as indicated by Eh and Mn 2+, Fe 2+ and H 2S distributions. Concentrations of S 2O 32- varied from below detection (<50 nM) to 600 nM while SO 32- concentrations generally were 2-3 times higher, 100-1500 nM. Depth distributions of the two species were roughly similar. Lowest concentrations were found in the oxidized zone, including both the oxic surface layer and the suboxic zone of intense manganese and iron reduction, and concentrations tended to increase through the suboxic and into the reduced, sulfidic zone. The similarity of SO 32- and S 2O 32- profiles suggested a close coupling of the cycling of the two species. Rates of consumption were suggested as the main factor governing their distribution. Rapid turnover times for S 2O 32- and H 2S of 4 and 1.1 h, respectively, were estimated for the upper 0-1 cm of a subtidal sediment.

  5. Non-sensitized selective photochemical reduction of CO2 to CO under visible light with an iron molecular catalyst.

    Science.gov (United States)

    Rao, Heng; Bonin, Julien; Robert, Marc

    2017-03-02

    A substituted tetraphenyl iron porphyrin, bearing positively charged trimethylammonio groups at the para position of each phenyl ring, demonstrates its ability as a homogeneous molecular catalyst to selectively reduce CO 2 to CO under visible light irradiation in organic media without the assistance of a sensitizer and no competitive hydrogen evolution for several days.

  6. Effect of iron oxide reductive dissolution on the transformation and immobilization of arsenic in soils: New insights from X-ray photoelectron and X-ray absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Jian-Xin [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing 400074 (China); Wang, Yu-Jun, E-mail: yjwang@issas.ac.cn [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Liu, Cun [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Wang, Li-Hua; Yang, Ke [Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of sciences, Shanghai 201204 (China); Zhou, Dong-Mei, E-mail: dmzhou@issas.ac.cn [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Li, Wei; Sparks, Donald L. [Environmental Soil Chemistry Group, Delaware Environmental Institute and Department of Plant and Soil Sciences, University of Delaware, Newark, DE 19717-1303 United States (United States)

    2014-08-30

    Graphical abstract: - Highlights: • Immobility and transformation of As on different Eh soils were investigated. • μ-XRF, XANES, and XPS were used to gain As distribution and speciation in soil. • Sorption capacity of As on anaerobic soil was much higher than that on oxic soil. • Fe oxides reductive dissolution is a key factor for As sorption and transformation. - Abstract: The geochemical behavior and speciation of arsenic (As) in paddy soils is strongly controlled by soil redox conditions and the sequestration by soil iron oxyhydroxides. Hence, the effects of iron oxide reductive dissolution on the adsorption, transformation and precipitation of As(III) and As(V) in soils were investigated using batch experiments and synchrotron based techniques to gain a deeper understanding at both macroscopic and microscopic scales. The results of batch sorption experiments revealed that the sorption capacity of As(V) on anoxic soil was much higher than that on control soil. Synchrotron based X-ray fluorescence (μ-XRF) mapping studies indicated that As was heterogeneously distributed and was mainly associated with iron in the soil. X-ray absorption near edge structure (XANES), micro-X-ray absorption near edge structure (μ-XANES) and X-ray photoelectron spectroscopy (XPS) analyses revealed that the primary speciation of As in the soil is As(V). These results further suggested that, when As(V) was introduced into the anoxic soil, the rapid coprecipitation of As(V) with ferric/ferrous ion prevented its reduction to As(III), and was the main mechanism controlling the immobilization of As. This research could improve the current understanding of soil As chemistry in paddy and wetland soils.

  7. Effect of iron oxide reductive dissolution on the transformation and immobilization of arsenic in soils: New insights from X-ray photoelectron and X-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Fan, Jian-Xin; Wang, Yu-Jun; Liu, Cun; Wang, Li-Hua; Yang, Ke; Zhou, Dong-Mei; Li, Wei; Sparks, Donald L.

    2014-01-01

    Graphical abstract: - Highlights: • Immobility and transformation of As on different Eh soils were investigated. • μ-XRF, XANES, and XPS were used to gain As distribution and speciation in soil. • Sorption capacity of As on anaerobic soil was much higher than that on oxic soil. • Fe oxides reductive dissolution is a key factor for As sorption and transformation. - Abstract: The geochemical behavior and speciation of arsenic (As) in paddy soils is strongly controlled by soil redox conditions and the sequestration by soil iron oxyhydroxides. Hence, the effects of iron oxide reductive dissolution on the adsorption, transformation and precipitation of As(III) and As(V) in soils were investigated using batch experiments and synchrotron based techniques to gain a deeper understanding at both macroscopic and microscopic scales. The results of batch sorption experiments revealed that the sorption capacity of As(V) on anoxic soil was much higher than that on control soil. Synchrotron based X-ray fluorescence (μ-XRF) mapping studies indicated that As was heterogeneously distributed and was mainly associated with iron in the soil. X-ray absorption near edge structure (XANES), micro-X-ray absorption near edge structure (μ-XANES) and X-ray photoelectron spectroscopy (XPS) analyses revealed that the primary speciation of As in the soil is As(V). These results further suggested that, when As(V) was introduced into the anoxic soil, the rapid coprecipitation of As(V) with ferric/ferrous ion prevented its reduction to As(III), and was the main mechanism controlling the immobilization of As. This research could improve the current understanding of soil As chemistry in paddy and wetland soils

  8. Effect of Amount of Carbon on the Reduction Efficiency of Iron Ore-Coal Composite Pellets in Multi-layer Bed Rotary Hearth Furnace (RHF)

    Science.gov (United States)

    Mishra, Srinibash; Roy, Gour Gopal

    2016-08-01

    The effect of carbon-to-hematite molar ratio has been studied on the reduction efficiency of iron ore-coal composite pellet reduced at 1523 K (1250 °C) for 20 minutes in a laboratory scale multi-layer bed rotary hearth furnace (RHF). Reduced pellets have been characterized through weight loss measurement, estimation of porosity, shrinkage, qualitative and quantitative phase analysis by XRD. Performance parameters such as the degree of reduction, metallization, carbon efficiency, productivity, and compressive strength have been calculated to compare the process efficacy at different carbon levels in the pellets. Pellets with optimum carbon-to-hematite ratio (C/Fe2O3 molar ratio = 1.66) that is much below the stoichiometric carbon required for direct reduction of hematite yielded maximum reduction, better carbon utilization, and productivity for all three layers. Top layer exhibited maximum reduction at comparatively lower carbon level (C/Fe2O3 molar ratio 2.33). Correlation between degree of reduction and metallization indicated non-isothermal kinetics influenced by heat and mass transfer in multi-layer bed RHF. Compressive strength of the partially reduced pellet with optimum carbon content (C/Fe2O3 molar ratio = 1.66) showed that they could be potentially used as an alternate feed in a blast furnace or any other smelting reactor.

  9. Age-related deposition of brain iron in normal adults: an in vivo susceptibility weighted imaging study

    International Nuclear Information System (INIS)

    Wang Qidong; Xu Xiaojun; Zhang Minming

    2008-01-01

    Objective: The purpose of this study was to investigate the effect of age on the iron concentration of the human brain. Methods: The brain iron level was evaluated in vivo in 78 healthy adult volunteers using a noninvasive magnetic resonance method termed susceptibility weighted imaging. The subjects were divided intothree groups due to different ages: young (22-35 years old, n=27), middle- aged (36-55 years old, n=35), and aged (56-78 years old, n=16). The phase values were measured on the corrected phase images in the globus pallidus, putamen, caudate, substantia nigra, red nucleus, thalamus and frontal white matter. The phase values of those regions measured from the subjects over than 30 years old were correlated with published values of brain iron concentration in normal adults to check the validity of the data. Then, the phase values of the three groups were tested for significant age-related differences using one-way ANOVA, followed by post hoc testing using least significant difference (LSD) procedure. Regression analysis was used to further examine age-related effects revealed by group comparisons, and to estimate the rates of age-related changes. Results: A strong negative correlation was found between the phase values and the published values of the brain iron concentration (r=-0.796, P= 0.032), which indicated that the higher the iron deposition level, the greater the negative phase values. In the putamen (F=20.115, P<0.01) and frontal white matter (F=3.536, P=0.034), significant differences were detected in the phase values of the three age groups. Linear regression analysis showed that phase values of the putamen, frontal white matter, and red nucleus decreased with age (The regression coefficients were -0.001, -0.001, and < -0.001 respectively, and the P value were all < 0.05), which indicated that the iron concentration of those brain structures increased with age. No significant age- related changes of the iron concentration were found in the

  10. Nanoscale zero-valent iron (nZVI) synthesis in a Mg-aminoclay solution exhibits increased stability and reactivity for reductive decontamination

    DEFF Research Database (Denmark)

    Hwang, Yuhoon; Lee, Young-Chul; Mines, Paul D.

    2014-01-01

    Nanoscale zero-valent iron (nZVI) has often been explored as a reductant for detoxification of pollutants in environmental clean-ups. Despite the large surface area and superior reactivity of nZVI, its limited stability is a major obstacle in applying nZVI for in situ subsurface remediation, e......ZVI particles with higher crystallinity were produced. Stability of nZVI particles were evaluated using a sedimentation test and a dynamic light scattering technique. The characteristic time increased from 6.71 to 83.8 min, and particle (aggregate diameter) size decreased from 5132 to 186 nm with increasing...

  11. Reduction of Parkinson's-related dysphonia by thyroplasty.

    Science.gov (United States)

    Roubeau, B; Bruel, M; de Crouy Chanel, O; Périé, S

    2016-12-01

    Parkinson's-related dysphonia has a negative impact on the quality of speech by increasing the effects of the associated dysarthria. When this dysphonia is related to vocal fold adduction defect, constituting a real glottic insufficiency, vocal fold medialization can be proposed after failure of intensive voice and speech therapy. Acoustic and aerodynamic voice and speech analysis techniques, perceptual evaluation and estimation of vocal handicap, associated with fiberoptic laryngoscopy were performed to determine the indication for vocal fold medialization in these patients with glottic insufficiency. Vocal fold medialization by Montgomery thyroplasty implant was performed under local anesthesia and neuroanalgesia in two patients with Parkinson's disease presenting a dysphonia refractory to speech therapy. Postoperative evaluation showed improvement of voice quality with an increased number of harmonics and improvement of aerodynamic parameters. Vocal fold medialization by Montgomery thyroplasty implant effectively improved voice quality in these two patients allowing a more effective vocal fold adduction. The reducing of the hypophonia has a positive effect on the quality of oral communication. The medialization thyroplasty technique, under local anesthesia, allows intraoperative control of the voice as well as removal of the implant when necessary. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  12. Iron status in 358 apparently healthy 80-year-old Danish men and women: relation to food composition and dietary and supplemental iron intake

    DEFF Research Database (Denmark)

    Milman, Nils; Pedersen, Agnes Nadelmann; Ovesen, Lars

    2004-01-01

    of age from a 1914 cohort study. Blood samples included serum ferritin and hemoglobin (Hb). A dietary survey was performed in 232 subjects (120 men, 112 women) using a dietary history method. Median serum ferritin was 100 mug/l in men and 78 mug/l in women (p300 mug/l (i.e., iron overload) were found......In Denmark, the intake of dietary iron has decreased since 1987, when the mandatory iron fortification of flour (30 mg carbonyl iron/kg) was stopped. Since there have been no studies of iron status in elderly Danes after the abolishment of iron fortification, there is a need to assess actual iron...... status in the elderly population. The objective was to evaluate iron status and the relationship with food composition and dietary and supplemental iron intake in an elderly population in Copenhagen County. Participants in this health examination survey were 358 subjects (171 men, 187 women) 80 years...

  13. Ultrasonic actuation for MEMS dormancy-related stiction reduction

    Science.gov (United States)

    Kaajakari, Ville; Kan, Shyi-Herng; Lin, Li-Jen; Lal, Amit; Rodgers, M. Steven

    2000-08-01

    The use of ultrasonic pulses incident on surface micromachines has been shown to reduce dormancy-related failure. We applied ultrasonic pulses from the backside of a silicon substrate carrying SUMMiT processed surface micromachined rotors, used earlier as ultrasonic motors. The amplitude of the pulses was less than what is required to actuate the rotor (sub-threshold actuation). By controlling the ultrasonic pulse exposure time it was found that pulsed samples had smaller actuation voltages as compared to non-pulsed samples after twelve-hour dormancy. This result indicates that the micromachine stiction to surfaces during dormant period can be effectively eliminated, resulting in long-term stability of surface micromachines in critical applications.

  14. Reduction-induced inward diffusion and crystal growth on the surfaces of iron-bearing silicate glasses

    DEFF Research Database (Denmark)

    Liu, S.J.; Tao, H.Z.; Zhang, Y.F.

    2015-01-01

    We investigate the sodium inward diffusion (i.e., sodium diffusion from surface toward interior) in iron containing alkaline earth silicate glasses under reducing conditions around Tg and the induced surface crystallization. The surface crystallization is caused by formation of a silicate-gel lay......+ ions have stronger bonds to oxygen and lower coordination number (4~5) than Ca2+, Sr2+ and Ba2+ ions. In contrast, a cristobalite layer forms in Ca-, Sr- and Ba-containing glasses....

  15. Age-related reduction of adaptive brain response during semantic integration is associated with gray matter reduction

    OpenAIRE

    Zhu, Zude; Yang, Fengjun; Li, Dongning; Zhou, Lianjun; Liu, Ying; Zhang, Ying; Chen, Xuezhi

    2017-01-01

    While aging is associated with increased knowledge, it is also associated with decreased semantic integration. To investigate brain activation changes during semantic integration, a sample of forty-eight 25-75 year-old adults read sentences with high cloze (HC) and low cloze (LC) probability while functional magnetic resonance imaging was conducted. Significant age-related reduction of cloze effect (LC vs. HC) was found in several regions, especially the left middle frontal gyrus (MFG) and ri...

  16. Utilization of subsurface microbial electrochemical systems to elucidate the mechanisms of competition between methanogenesis and microbial iron(III)/humic acid reduction in Arctic peat soils

    Science.gov (United States)

    Friedman, E. S.; Miller, K.; Lipson, D.; Angenent, L. T.

    2012-12-01

    High-latitude peat soils are a major carbon reservoir, and there is growing concern that previously dormant carbon from this reservoir could be released to the atmosphere as a result of continued climate change. Microbial processes, such as methanogenesis and carbon dioxide production via iron(III) or humic acid reduction, are at the heart of the carbon cycle in Arctic peat soils [1]. A deeper understanding of the factors governing microbial dominance in these soils is crucial for predicting the effects of continued climate change. In previous years, we have demonstrated the viability of a potentiostatically-controlled subsurface microbial electrochemical system-based biosensor that measures microbial respiration via exocellular electron transfer [2]. This system utilizes a graphite working electrode poised at 0.1 V NHE to mimic ferric iron and humic acid compounds. Microbes that would normally utilize these compounds as electron acceptors donate electrons to the electrode instead. The resulting current is a measure of microbial respiration with the electrode and is recorded with respect to time. Here, we examine the mechanistic relationship between methanogenesis and iron(III)- or humic acid-reduction by using these same microbial-three electrode systems to provide an inexhaustible source of alternate electron acceptor to microbes in these soils. Chamber-based carbon dioxide and methane fluxes were measured from soil collars with and without microbial three-electrode systems over a period of four weeks. In addition, in some collars we simulated increased fermentation by applying acetate treatments to understand possible effects of continued climate change on microbial processes in these carbon-rich soils. The results from this work aim to increase our fundamental understanding of competition between electron acceptors, and will provide valuable data for climate modeling scenarios. 1. Lipson, D.A., et al., Reduction of iron (III) and humic substances plays a major

  17. Using learning curves on energy-efficient technologies to estimate future energy savings and emission reduction potentials in the U.S. iron and steel industry

    Energy Technology Data Exchange (ETDEWEB)

    Karali, Nihan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Park, Won Young [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); McNeil, Michael A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-06-18

    Increasing concerns on non-sustainable energy use and climate change spur a growing research interest in energy efficiency potentials in various critical areas such as industrial production. This paper focuses on learning curve aspects of energy efficiency measures in the U.S iron and steel sector. A number of early-stage efficient technologies (i.e., emerging or demonstration technologies) are technically feasible and have the potential to make a significant contribution to energy saving and CO2 emissions reduction, but fall short economically to be included. However, they may also have the cost effective potential for significant cost reduction and/or performance improvement in the future under learning effects such as ‘learning-by-doing’. The investigation is carried out using ISEEM, a technology oriented, linear optimization model. We investigated how steel demand is balanced with/without the availability learning curve, compared to a Reference scenario. The retrofit (or investment in some cases) costs of energy efficient technologies decline in the scenario where learning curve is applied. The analysis also addresses market penetration of energy efficient technologies, energy saving, and CO2 emissions in the U.S. iron and steel sector with/without learning impact. Accordingly, the study helps those who use energy models better manage the price barriers preventing unrealistic diffusion of energy-efficiency technologies, better understand the market and learning system involved, predict future achievable learning rates more accurately, and project future savings via energy-efficiency technologies with presence of learning. We conclude from our analysis that, most of the existing energy efficiency technologies that are currently used in the U.S. iron and steel sector are cost effective. Penetration levels increases through the years, even though there is no price reduction. However, demonstration technologies are not economically

  18. Reference Values of Reticulocyte Hemoglobin Content and Their Relation With Other Indicators of Iron Status in Healthy Children.

    Science.gov (United States)

    López-Ruzafa, Encarnación; Vázquez-López, Maria A; Lendinez-Molinos, Francisco; Poveda-González, Juan; Galera-Martínez, Rafael; Bonillo-Perales, Antonio; Martín-González, Manuel

    2016-10-01

    Reticulocyte hemoglobin content (CHr) is considered an indicator of functional iron deficiency, but is understudied in children. The goals of this study are to determine the reference intervals for CHr in healthy children, and their relation with iron parameters, erythropoiesis, and individual conditions. A total of 902 children without iron deficiency, aged 1 to 11 years were analyzed in a cross-sectional study. Besides a physical examination of the subjects and a questionnaire completed by their parents, the complete blood count, serum transferrin receptor, ferritin, transferrin saturation, erythrocyte protoporphyrin, serum erythropoietin, C-reactive protein, and CHr levels were measured. Changes in CHr, iron status, and erythropoiesis at different age intervals were analyzed and linear multiple regression was used to identify the factors that determine CHr variability. Mean value obtained for CHr was 30.9±1.8 pg (P2.5-P97.5: 26.9 to 34.3 pg), but the influence of age on CHr (the values increased with age) and on the iron parameters justified the establishment of different reference ranges. In addition to age, nutritional status, hematologic measurements, reticulocytes, transferrin saturation, and erythrocyte protoporphyrin accounted for 39% of CHr variability.

  19. Iron Abundance in the Prototype PG 1159 Star, GW Vir Pulsator PG 1159-035, and Related Objects

    Science.gov (United States)

    Werner, K.; Rauch, T.; Kruk, J. W.; Kurucz, R. L.

    2011-01-01

    We performed an iron abundance determination of the hot, hydrogen deficient post-AGB star PG 1159-035. which is the prototype of the PG 1159 spectral class and the GW Vir pulsators, and of two related objects (PG 1520+525, PG 1144+005), based on the first detection of Fe VIII lines in stellar photospheres. In another PG 1159 star. PG 1424+535. we detect Fe VII lines. In all four stars, each within T(sub eff) = 110,000-150,000 K, we find a solar iron abundance. This result agrees with our recent abundance analysis of the hottest PG 1159 stars (T(sub eff) = 150,000-200,000 K) that exhibit Fe x lines. On the whole, we find that the PG 1159 stars are not significantly iron deficient, in contrast to previous notions.

  20. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... also are hoping to determine which iron supplements work best to treat iron-deficiency anemia in children who do not consume the daily recommended amount of iron. Read less Participate in NHLBI Clinical Trials We lead or sponsor many studies related to iron-deficiency anemia. See if you ...

  1. The barium-to-iron enrichment versus age relation of ancient disc stars

    Science.gov (United States)

    Fuhrmann, K.; Chini, R.; Kaderhandt, L.; Chen, Z.; Lachaume, R.

    2017-11-01

    We report an intrinsically precise relation of the barium-to-iron enrichment as a function of age for a local, volume-complete (N = 30) sample of ancient Population II (τ ≥ 12 Gyr) and intermediate-disc stars (τ ≃ 10 Gyr), which suggests a common, r-process-dominated nucleosynthesis site for both elements in the early stages of the Milky Way. Deviants from this empirical relation are to a large extent identified as formerly known or new blue straggler stars. We report in particular the striking case of the Population II star HD 159062, whose barium overabundance is difficult to explain without wind accretion of s-process material from a former asymptotic giant branch (AGB) primary that very likely survived as a white dwarf companion. The weak but significant barium enhancement that we measure for HR 3578 and 104 Tau also suggests that both may be accompanied by faint degenerate companions. If confirmed through precision astrometry or direct imaging observations, this would mean a very efficient method to uncover ancient stellar remnant companions around solar-type stars.

  2. Galvanic corrosion of copper-cast iron couples in relation to the Swedish radioactive waste canister concept

    International Nuclear Information System (INIS)

    Smart, N.R.; Fennell, P.A.H.; Rance, A.P.; Werme, L.O.

    2004-01-01

    conditions the galvanic corrosion rates of iron coupled to copper are close to the values observed for anaerobic corrosion rates of uncoupled iron. The results from the work presented in the paper will be discussed in relation to understanding the evolution of the environment within the annulus of the SKB canister if premature failure of the outer copper canister were to occur. (authors)

  3. Reduction of hexavalent chromium by ferrous iron: A process of chromium isotope fractionation and its relevance to natural environments

    DEFF Research Database (Denmark)

    Døssing, Lasse Nørbye; Dideriksen, Knud; Stipp, Susan Louise Svane

    2011-01-01

    Stable chromium (Cr) isotopes can be used as a tracer for changing redox conditions in modern marine systems and in the geological record. We have investigated isotope fractionation during reduction of Cr(VI)aq by Fe(II)aq. Reduction of Cr(VI)aq by Fe(II)aq in batch experiments leads to significant...

  4. Age-related reduction of adaptive brain response during semantic integration is associated with gray matter reduction.

    Directory of Open Access Journals (Sweden)

    Zude Zhu

    Full Text Available While aging is associated with increased knowledge, it is also associated with decreased semantic integration. To investigate brain activation changes during semantic integration, a sample of forty-eight 25-75 year-old adults read sentences with high cloze (HC and low cloze (LC probability while functional magnetic resonance imaging was conducted. Significant age-related reduction of cloze effect (LC vs. HC was found in several regions, especially the left middle frontal gyrus (MFG and right inferior frontal gyrus (IFG, which play an important role in semantic integration. Moreover, when accounting for global gray matter volume reduction, the age-cloze correlation in the left MFG and right IFG was absent. The results suggest that brain structural atrophy may disrupt brain response in aging brains, which then show less brain engagement in semantic integration.

  5. Synthesis of novel magnetic iron metal-silica (Fe-SBA-15) and magnetite-silica (Fe{sub 3}O{sub 4}-SBA-15) nanocomposites with a high iron content using temperature-programed reduction

    Energy Technology Data Exchange (ETDEWEB)

    Yiu, H H P [Department of Chemistry, University of Liverpool, Liverpool, Merseyside L69 7ZD (United Kingdom); Keane, M A [Chemical Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Lethbridge, Z A D [Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom); Lees, M R [Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom); Haj, A J El; Dobson, J [Institute of Science and Technology in Medicine, Keele University, Thornburrow Drive, Hartshill, Stoke-on-Trent ST4 7QB (United Kingdom)], E-mail: j.p.dobson@keele.ac.uk

    2008-06-25

    Magnetic iron metal-silica and magnetite-silica nanocomposites have been prepared via temperature-programed reduction (TPR) of an iron oxide-SBA-15 (SBA: Santa Barbara Amorphous) composite. TPR of the starting SBA-15 supported Fe{sub 2}O{sub 3} generated Fe{sub 3}O{sub 4} and FeO as stepwise intermediates in the ultimate formation of Fe-SBA-15. The composite materials have been characterized by means of x-ray diffraction, high resolution transmission electron microscopy and SQUID (superconducting quantum interference device) magnetometry. The Fe oxide and metal components form a core, as nanoscale particles, that is entrapped in the SBA-15 pore network. Fe{sub 3}O{sub 4}-SBA-15 and Fe-SBA-15 exhibited superparamagnetic properties with a total magnetization value of 17 emu g{sup -1}. The magnetite-silica composite (at an Fe{sub 3}O{sub 4} loading of 30% w/w) delivered a magnetization that exceeded values reported in the literature or obtained with commercial samples. Due to the high pore volume of the mesoporous template, the magnetite content can be increased to 83% w/w with a further enhancement of magnetization.

  6. Nitrate-dependent iron oxidation limits iron transport in anoxic ocean regions

    Science.gov (United States)

    Scholz, Florian; Löscher, Carolin R.; Fiskal, Annika; Sommer, Stefan; Hensen, Christian; Lomnitz, Ulrike; Wuttig, Kathrin; Göttlicher, Jörg; Kossel, Elke; Steininger, Ralph; Canfield, Donald E.

    2016-11-01

    Iron is an essential element for life on Earth and limits primary production in large parts of the ocean. Oxygen-free continental margin sediments represent an important source of bioavailable iron to the ocean, yet little of the iron released from the seabed reaches the productive sea surface. Even in the anoxic water of oxygen minimum zones, where iron solubility should be enhanced, most of the iron is rapidly re-precipitated. To constrain the mechanism(s) of iron removal in anoxic ocean regions we explored the sediment and water in the oxygen minimum zone off Peru. During our sampling campaign the water column featured two distinct redox boundaries separating oxic from nitrate-reducing (i.e., nitrogenous) water and nitrogenous from weakly sulfidic water. The sulfidic water mass in contact with the shelf sediment contained elevated iron concentrations >300 nM. At the boundary between sulfidic and nitrogenous conditions, iron concentrations dropped sharply to <20 nM coincident with a maximum in particulate iron concentration. Within the iron gradient, we found an increased expression of the key functional marker gene for nitrate reduction (narG). Part of this upregulation was related to the activity of known iron-oxidizing bacteria. Collectively, our data suggest that iron oxidation and removal is induced by nitrate-reducing microbes, either enzymatically through anaerobic iron oxidation or by providing nitrite for an abiotic reaction. Given the important role that iron plays in nitrogen fixation, photosynthesis and respiration, nitrate-dependent iron oxidation likely represents a key-link between the marine biogeochemical cycles of nitrogen, oxygen and carbon.

  7. A budget impact analysis of parenteral iron treatments for iron deficiency anemia in the UK: reduced resource utilization with iron isomaltoside 1000.

    Science.gov (United States)

    Pollock, Richard F; Muduma, Gorden

    2017-01-01

    The reported prevalence of iron deficiency anemia (IDA) varies widely but estimates suggest that 3% of men and 8% of women have IDA in the UK. Parenteral iron is indicated for patients intolerant or unresponsive to oral iron or requiring rapid iron replenishment. This study evaluated differences in the cost of treating these patients with iron isomaltoside (Monofer ® , IIM) relative to other intravenous iron formulations. A budget impact model was developed to evaluate the cost of using IIM relative to ferric carboxymaltose (Ferinject ® , FCM), low molecular weight iron dextran (Cosmofer ® , LMWID), and iron sucrose (Venofer ® , IS) in patients with IDA. To establish iron need, iron deficits were modeled using a simplified dosing table. The base case analysis was conducted over 1 year in patients with IDA with mean bodyweight of 82.4 kg (SD 22.5 kg) and hemoglobin levels of 9.99 g/dL (SD 1.03 g/dL) based on an analysis of patient characteristics in IDA trials. Costs were modeled using UK health care resource groups. Using IIM required 1.3 infusions to correct the mean iron deficit, compared with 1.3, 1.8, and 7.7 with LMWID, FCM, and IS, respectively. Patients using IIM required multiple infusions in 35% of cases, compared with 35%, 77%, and 100% of patients with LMWID, FCM, and IS, respectively. Total costs were estimated to be GBP 451 per patient with IIM or LMWID, relative to GBP 594 with FCM (a GBP 143 or 24% saving with IIM) or GBP 2,600 with IS (a GBP 2,149 or 83% saving with IIM). Using IIM or LMWID in place of FCM or IS resulted in a marked reduction in the number of infusions required to correct iron deficits in patients with IDA. The reduction in infusions was accompanied by substantial reductions in cost relative to FCM and IS over 1 year.

  8. Relation between feeding mechanisms and solidification mode in 380 aluminium alloy with different iron contents

    International Nuclear Information System (INIS)

    Tovio, D. O.; Gonzalez, A.C.; Mugica, G. W.; Cuyas, J. C.

    2003-01-01

    In the present work the effect of iron (0.15, 0.42 and 0.86%) content in feeding mechanisms for 380 aluminium alloy has been studied. The feeding capacity has been evaluated by a device that produces a barrier removable to allowing the movement of the inter dendritic liquid. The results show the flow of different quantity of liquid, it depends of the temperature of operating the device and of the iron content. For minimum and maximum iron content, the inter dendritic and bursts feeding mechanisms are fundamentally involved, for 0.42% of iron the feeding mechanisms was the inter dendritic. The authors establish this behavior by the solidification mode of alloy, which promotes the presence of particles of Si or plates of b-Al 3 FeDi phase, in the inter dendritic channels and produce the different feeding mechanisms. (Author) 15 refs

  9. Radium desorption, manganese and iron dissolution from sand filters of a conventional ground water treatment plant under reductive conditions

    International Nuclear Information System (INIS)

    Al-Hobaib, A.S.; Al-Sulaiman, K.M.; Al-Dhayan, D.M.; Al-Suhybani, A.A.

    2006-01-01

    Sand filters are used as a filter bed in many ground water treatment plants to remove the physical contaminants and oxidation products. A build-up of radioactivity may take place on the granules, where iron and manganese oxides are deposited and form thin films on the surface of sand filter. The oxides of iron and manganese play an important role in adsorbing radium from ground water. The disposal of those granules makes a significant problem. A batch technique is used for solubilization of radium from sand filters in the presence of some organic acids, which act as reducing agents. These acids are formic acid, acetic acid, benzoic acid, succinic acid, oxalic acid, phthalic acid, and adipic acid. The data were obtained as a function of acidity, temperature, contact time and liquid/solid ratio particle size and shaking speed. It was found that oxalic acid was the best for radium removal. The effectiveness of these acids on radium removal was as follows: oxalic acid > phthalic acid > adipic acid > succinic acid > formic acid > acetic acid. The maximum removal obtained was 69.9% at 1M oxalic acid at 8 ml/g ratio. Reaction kinetics and mechanism parameters of the dissolution process were studied and compared with other published data. (author)

  10. Electrochemical CO2 Reduction by Ni-containing Iron Sulfides: How Is CO2 Electrochemically Reduced at Bisulfide-Bearing Deep-sea Hydrothermal Precipitates?

    International Nuclear Information System (INIS)

    Yamaguchi, Akira; Yamamoto, Masahiro; Takai, Ken; Ishii, Takumi; Hashimoto, Kazuhito; Nakamura, Ryuhei

    2014-01-01

    The discovery of deep-sea hydrothermal vents on the late 1970's has led to many hypotheses concerning chemical evolution in the prebiotic ocean and the early evolution of energy metabolism in ancient Earth. Such studies stand on the quest for the bioenergetic evolution to utilize reducing chemicals such as H 2 for CO 2 reduction and carbon assimilation. In addition to the direct reaction of H 2 and CO 2 , the electrical current passing across a bisulfide-bearing chimney structure has pointed to the possible electrocatalytic CO 2 reduction at the cold ocean-vent interface (R. Nakamura, et al. Angew. Chem. Int. Ed. 2010, 49, 7692 − 7694). To confirm the validity of this hypothesis, here, we examined the energetics of electrocatalytic CO 2 reduction by iron sulfide (FeS) deposits at slightly acidic pH. Although FeS deposits inefficiently reduced CO 2 , the efficiency of the reaction was substantially improved by the substitution of Fe with Ni to form FeNi 2 S 4 (violarite), of which surface was further modified with amine compounds. The potential-dependent activity of CO 2 reduction demonstrated that CO 2 reduction by H 2 in hydrothermal fluids was involved in a strong endergonic electron transfer reaction, suggesting that a naturally occurring proton-motive force (PMF) as high as 200 mV would be established across the hydrothermal vent chimney wall. However, in the chimney structures, H 2 generation competes with CO 2 reduction for electrical current, resulting in rapid consumption of the PMF. Therefore, to maintain the PMF and the electrosynthesis of organic compounds in hydrothermal vent mineral deposits, we propose a homeostatic pH regulation mechanism of FeS deposits, in which elemental hydrogen stored in the hydrothermal mineral deposits is used to balance the consumption of the electrochemical gradient by H 2 generation

  11. Evaluation of Social Performance and Related Factors in Iranian Central Iron Ore company workers

    Directory of Open Access Journals (Sweden)

    Gholamhossein Halvani

    2013-01-01

    Full Text Available Introduction: Psychological and social health is the main problems of workers population, which can increase productivity at work and physical and mental health and provide or decline in these aspects. Materials and Methods: this study was descriptive and crosses - sectional and has been performed on 388 Iranian central iron ore company workers. The tool of study was standard GHQ-28 question are that has been measured under social performance scale. Results: 49.3 and 49 percent of the people have favorable and average score from the state of the social function condition and 1.8 percent of people have severe social dysfunction and besides the employees have less work experienced that have more social dysfunction and there is a relationship between the P = 0.026. With satisfaction with the status of social dysfunction (P = 0 and with the consent of the income (P = 0 there is significant relationship. Conclusion: In this study, a significant percentage of mineworkers were not in good condition from health, social functioning. It reveals the importance of addressing health issues and vulnerable working class, Intervention studies conducted by employers to improve job satisfaction and increased income and received social support from him, can increase the health indicators related to the body and mind.

  12. Solid-solution partitioning and thionation of diphenylarsinic acid in a flooded soil under the impact of sulfate and iron reduction

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Meng [Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Tu, Chen [Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Hu, Xuefeng; Zhang, Haibo [Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Lijuan [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Wei, Jing [Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Li, Yuan [Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Luo, Yongming, E-mail: ymluo@yic.ac.cn [Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Christie, Peter [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)

    2016-11-01

    DPAA. - Highlights: • We first investigated the solid-solution partitioning of DPAA in a flooded soil. • We first examined the impacts of sulfate and iron reduction on DPAA partitioning. • Elevated DPAA mobilization and thionation was observed in sulfide soil. • DPAA mobilization associated with Fe(III) reductive dissolution was demonstrated. • Enhanced mobilization of DPAA and sulfate reduction promoted DPAA thionation.

  13. Study on energy saving and the CO{sub 2} reduction plan of Korean iron and steel industry

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.W.; Kim, J.I.; Kim, S.R. [Korea Energy Economics Institute, Euiwang (Korea, Republic of)

    1997-08-01

    An iron and steel company which consumes a lot of energy should continue restructuring with integrated management methods based on a thorough profitability principle together with continuous investment in green technology development, and actively search for advancing plans to upper and lower streams through vigorous foreign investment. The iron and steel industry now must realize that environmental strategy will eventually be converted into the profit of the company eventually, and escape from the reactive attitude of the past on environment. It is urgently required that they possess an aggressive management strategy that could capture the impact of environmental regulation which may be far greater than the Uruguay Round (UR) of the past as the opportunistic factor that would rather increase the power of the company. Now enterprises need a change of attitude that handles the capital invested in environment as an aggressive strategic element that could guarantee the profit for the future not as mere concept of expenses. As in the case of the 3M company, the concept of `Polluter Pays Principle` should be accepted as the 3P concept of pollution- prevention compensation principle called as the concept of `Pollution Prevention Pays`. That is, expanding the use of clean energy and raising the public image as an environment-friendly enterprise has become an important assignment of an entrepreneur now. First of all, all employees including top management must renew their recognition on environmental management. They should be able to have collective wisdom enough to take advantage of the manpower and resources required for minimizing environmental damages as the investment or opportunistic element that could bring tangible and intangible profits in the future. 33 refs., 2 figs., 11 tabs.

  14. Phase III randomized trial comparing intravenous to oral iron in patients with cancer-related iron deficiency anemia not on erythropoiesis stimulating agents.

    Science.gov (United States)

    Noronha, Vanita; Joshi, Amit; Patil, Vijay Maruti; Banavali, Shripad D; Gupta, Sudeep; Parikh, Purvish M; Marfatia, Shalaka; Punatar, Sachin; More, Sucheta; Goud, Supriya; Nakti, Dipti; Prabhash, Kumar

    2018-04-01

    We aimed to find the optimal route of iron supplementation in patients with malignancy and iron deficiency (true or functional) anemia not receiving erythropoiesis stimulating agents (ESA). Adult patients with malignancy requiring chemotherapy, hemoglobin (Hb) 10% were randomized to intravenous (IV) iron sucrose or oral ferrous sulfate. The primary endpoint was change in Hb from baseline to 6 weeks. Secondary endpoints included blood transfusion, quality of life (QoL), toxicity, response and overall survival. A total of 192 patients were enrolled over 5 years: 98 on IV arm and 94 on oral arm. Median age was 51 years; over 95% patients had solid tumors. The mean absolute increase in Hb at 6 weeks was 0.11 g/dL (standard deviation [SD]: 1.48) in IV arm and -0.16 g/dL (SD: 1.36) in oral arm, P = 0.23. Twenty-three percent patients on IV iron and 18% patients on oral iron had a rise in Hb of ≥1 g/dL at 6 weeks, P = 0.45. Thirteen patients (13.3%) on the IV iron arm and 14 patients (14.9%) on the oral arm required blood transfusion, P = 1.0. Gastrointestinal toxicity (any grade) developed in 41% patients on IV iron and 44% patients on oral iron, P = 1.0. 5 patients on IV iron and none on oral iron had hypersensitivity, P = 0.06. QoL was not significantly different between the two arms. IV iron was not superior to oral iron in patients with malignancy on chemotherapy and iron deficiency anemia. © 2017 John Wiley & Sons Australia, Ltd.

  15. Reaction-Based Reactive Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center

    Energy Technology Data Exchange (ETDEWEB)

    Burgos, W.D.

    2009-09-02

    This report summarizes research conducted in conjunction with a project entitled “Reaction-Based Reactive Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center”, which was funded through the Integrative Studies Element of the former NABIR Program (now the Environmental Remediation Sciences Program) within the Office of Biological and Environmental Research. Dr. William Burgos (The Pennsylvania State University) was the overall PI/PD for the project, which included Brian Dempsey (Penn State), Gour-Tsyh (George) Yeh (Central Florida University), and Eric Roden (formerly at The University of Alabama, now at the University of Wisconsin) as separately-funded co-PIs. The project focused on development of a mechanistic understanding and quantitative models of coupled Fe(III)/U(VI) reduction in FRC Area 2 sediments. The work builds on our previous studies of microbial Fe(III) and U(VI) reduction, and was directly aligned with the Scheibe et al. ORNL FRC Field Project at Area 2.

  16. High-performance oxygen reduction catalysts in both alkaline and acidic fuel cells based on pre-treating carbon material and iron precursor

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ping; Barkholtz, Heather M.; Wang, Ying; Xu, Weilin; Liu, Dijia; Zhuang, Lin

    2017-12-01

    We demonstrate a new and simple method for pre-treating the carbon material and iron precursor to prepare oxygen reduction reaction (ORR) catalysts, which can produce super-high performance and stability in alkaline solution, with high performance in acid solution. This strategy using cheap materials is simply controllable. Moreover, it has achieved smaller uniform nanoparticles to exhibit high stability, and the synergetic effect of Fe and N offered much higher performance in ORR than commercial Pt/C, with high maximum power density in alkaline and acid fuel cell test. So it can make this kind of catalysts be the most promising alternatives of Pt-based catalysts with best performance/price.

  17. DIRECT INFUSION ESI-MS APPLIED IN THE DETECTION OF BYPRODUCTS DUE TO REDUCTIVE DEGRADATION OF ACETAMIPRID BY ZERO-VALENT IRON

    Directory of Open Access Journals (Sweden)

    Jean C. Cruz

    2015-09-01

    Full Text Available This study investigated the reductive degradation of acetamiprid (5 mg L-1 in aqueous medium (at pH 2.0 induced by zero-valent iron (50 mg. The process was monitored using high-performance liquid chromatography (HPLC to determine the degradation rate as a function of reaction time, and direct infusion electrospray ionization mass spectrometry (DI-ESI-MS to search for (and potentially characterize any possible byproducts formed during degradation. The results obtained via HPLC showed that after 60 min, the degradation of the substrate reached nearly 100% in an acidic medium, whereas the mineralization rate (as determined by total organic carbon measurements was as low as 3%. Data obtained by DI-ESI-MS showed that byproducts were formed mainly by insertions of hydrogen atoms into the nitrile, imine, and pyridine ring moieties, in addition to the observation of chlorine substitution by hydrogen replacement (hydrodechlorination reactions.

  18. Frequency of Hereditary Hemochromatosis (HFE) Gene Mutations in Egyptian Beta Thalassemia Patients and its Relation to Iron Overload.

    Science.gov (United States)

    Enein, Azza Aboul; El Dessouky, Nermine A; Mohamed, Khalda S; Botros, Shahira K A; Abd El Gawad, Mona F; Hamdy, Mona; Dyaa, Nehal

    2016-06-15

    This study aimed to detect the most common HFE gene mutations (C282Y, H63D, and S56C) in Egyptian beta thalassemia major patients and its relation to their iron status. The study included 50 beta thalassemia major patients and 30 age and sex matched healthy persons as a control group. Serum ferritin, serum iron and TIBC level were measured. Detection of the three HFE gene mutations (C282Y, H63D and S65C) was done by PCR-RFLP analysis. Confirmation of positive cases for the mutations was done by sequencing. Neither homozygote nor carrier status for the C282Y or S65C alleles was found. The H63D heterozygous state was detected in 5/50 (10%) thalassemic patients and in 1/30 (3.3%) controls with no statistically significant difference between patients and control groups (p = 0.22). Significantly higher levels of the serum ferritin and serum iron in patients with this mutation (p = 001). Our results suggest that there is an association between H63D mutation and the severity of iron overload in thalassemic patients.

  19. Relation between Omega 3 Fatty Acid, Iron, Zinc and Treatment of ADHD

    Directory of Open Access Journals (Sweden)

    Maryam Shalileh

    2014-10-01

    Full Text Available In some studies, it is suggested that a number of dietary factors including essential fatty acid, iron and zinc deficiency, may be linked to attention-deficit/hyperactivity-disorder (ADHD. However, the exact mechanism of this relationship is yet unclear. The purpose of this study is to investigate the relationship between omega-3 fatty acids, zinc, and iron in etiopathology and management of ADHD. For the purpose of this study, Science Direct, PubMed, and Medline databases were explored and thirty-four relevant articles in english language were collected. Eighteen out of twenty-two studies confirmed the relationship between omega-3 fatty acid and ADHD. In addition, the role of insufficient store of iron in developing ADHD symptoms and the positive effect of iron supplement in improvement of ADHD behavioral symptoms have been shown. Also, plasma zinc concentration in children with ADHD was lower than the normal population, and the effect of zinc supplement on reducing on attentive-deficit symptoms was contradictory. Although polyunsaturated fatty acids (PUFA and iron supplements are not suggested as main treatment for ADHD, but if future studies confirm the positive results of that, use of these supplements as complementary treatment will affect ADHD symptoms. Considering the little amount of studies on zinc, more research is necessary.

  20. Motor development in 9-month-old infants in relation to cultural differences and iron status.

    Science.gov (United States)

    Angulo-Barroso, Rosa M; Schapiro, Lauren; Liang, Weilang; Rodrigues, Onike; Shafir, Tal; Kaciroti, Niko; Jacobson, Sandra W; Lozoff, Betsy

    2011-03-01

    Motor development, which allows infants to explore their environment, promoting cognitive, social, and perceptual development, can be influenced by cultural practices and nutritional factors, such as iron deficiency. This study compared fine and gross motor development in 209 9-month-old infants from urban areas of China, Ghana, and USA (African-Americans) and considered effects of iron status. Iron deficiency anemia was most common in the Ghana sample (55%) followed by USA and China samples. Controlling for iron status, Ghanaian infants displayed precocity in gross motor development and most fine-motor reach-and-grasp tasks. US African-Americans performed the poorest in all tasks except bimanual coordination and the large ball. Controlling for cultural site, iron status showed linear trends for gross motor milestones and fine motor skills with small objects. Our findings add to the sparse literature on infant fine motor development across cultures. The results also indicate the need to consider nutritional factors when examining cultural differences in infant development. Copyright © 2010 Wiley Periodicals, Inc.

  1. Iron(II) phthalocyanine covalently functionalized graphene as a highly efficient non-precious-metal catalyst for the oxygen reduction reaction in alkaline media

    International Nuclear Information System (INIS)

    Liu, Ying; Wu, Yan-Ying; Lv, Guo-Jun; Pu, Tao; He, Xing-Quan; Cui, Li-Li

    2013-01-01

    Graphical abstract: The fabricated FePc-Gr catalyst for ORR exhibited high activity, favoring a direct 4-electron process, good stability and selectivity, all of which should be attributed to its high conductivity, the synergistic effect between FePc and graphene, as well as the formation of stable FePc-Gr composite through covalent bonding and π–π interaction. - Abstract: A novel iron(II) phthalocyanine covalently modified graphene (FePc-Gr) was synthesized by reduction of the product obtained through an amidation reaction between carboxyl-functionalized graphene oxide (CFGO) and iron(II) tetra-aminophthalocyanine (FeTAPc). The FePc-Gr hybird was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy (RS) and X-ray photoelectron spectroscopy (XPS), respectively. The electrocatalytic properties of FePc-Gr toward the oxygen reduction reaction (ORR) were evaluated using cyclic voltammetry (CV) and linear sweep voltammetry methods. The peak potential of the ORR on the FePc-Gr catalyst was found to be about −0.12 V vs. SCE in 0.1 M NaOH solution, which was 180 and 360 mV more positive than that on FeTAPc and bare GCE, respectively. The rotating disk electrode (RDE) and rotating ring disk electrode (RRDE) measurements revealed that the ORR mechanism was nearly via a direct four-electron pathway to water on FePc-Gr. The current still remained 83.5% of its initial after chronoamperometric test for 10,000 s. Nevertheless, Pt/C catalyst only retained 40.5% of its initial current. The peak potential and peak current changed slightly when 3 M methanol was introduced. So the FePc-Gr composite catalyst for ORR exhibited high activity, good stability and methanol-tolerance, which could be used as a promising Pt-free catalyst for ORR in alkaline direct methanol fuel cell (DMFC)

  2. On the Use of Reduction Relations to Relate Different Types of Agent Models

    NARCIS (Netherlands)

    Treur, J.

    2011-01-01

    This paper focuses on relationships between agent models and their physical realisations. Approaches on reduction from philosophical literature are analysed in a formalised manner, and extended by incorporating context-dependency w.r.t. specific makeups for their realisations. It is shown how these

  3. Evaporated self-supporting foils of enriched iron from the in-situ reduction of Fe2O3

    International Nuclear Information System (INIS)

    Riel, W.D.

    1976-01-01

    This paper describes the reduction of isotopically enriched Fe 2 O 3 usng a controlled thermite reaction. The method will produce strain free evaporated films of 100-300 μg/cm 2 which can be floated and mounted, using standard techniques, to make strong self-supporting targets. (author)

  4. Heterogeneous electron transfer and oxygen reduction reaction at nanostructured iron(II) phthalocyanine and its MWCNTs nanocomposites

    CSIR Research Space (South Africa)

    Mamuru, SA

    2010-05-01

    Full Text Available species within the porous layers of MWCNTs. Electron transfer process is much easier at the EPPGE-MWCNT and EPPGE-MWCNT-nanoFePc compared to the other electrodes. The best response for oxygen reduction reaction was at the EPPGE-MWCNTnanoFePc, yielding a 4...

  5. Microbial reduction of structural iron in interstratified illite-smectite minerals by a sulfate-reducing bacterium.

    Science.gov (United States)

    Liu, D; Dong, H; Bishop, M E; Zhang, J; Wang, H; Xie, S; Wang, S; Huang, L; Eberl, D D

    2012-03-01

    Clay minerals are ubiquitous in soils, sediments, and sedimentary rocks and could coexist with sulfate-reducing bacteria (SRB) in anoxic environments, however, the interactions of clay minerals and SRB are not well understood. The objective of this study was to understand the reduction rate and capacity of structural Fe(III) in dioctahedral clay minerals by a mesophilic SRB, Desulfovibrio vulgaris and the potential role in catalyzing smectite illitization. Bioreduction experiments were performed in batch systems, where four different clay minerals (nontronite NAu-2, mixed-layer illite-smectite RAr-1 and ISCz-1, and illite IMt-1) were exposed to D. vulgaris in a non-growth medium with and without anthraquinone-2,6-disulfonate (AQDS) and sulfate. Our results demonstrated that D. vulgaris was able to reduce structural Fe(III) in these clay minerals, and AQDS enhanced the reduction rate and extent. In the presence of AQDS, sulfate had little effect on Fe(III) bioreduction. In the absence of AQDS, sulfate increased the reduction rate and capacity, suggesting that sulfide produced during sulfate reduction reacted with the phyllosilicate Fe(III). The extent of bioreduction of structural Fe(III) in the clay minerals was positively correlated with the percentage of smectite and mineral surface area of these minerals. X-ray diffraction, and scanning and transmission electron microscopy results confirmed formation of illite after bioreduction. These data collectively showed that D. vulgaris could promote smectite illitization through reduction of structural Fe(III) in clay minerals. © 2011 Blackwell Publishing Ltd.

  6. Heterogeneous photocatalysis using TiO2 modified with hydrotalcite and iron oxide under UV-visible irradiation for color and toxicity reduction in secondary textile mill effluent.

    Science.gov (United States)

    Arcanjo, Gemima Santos; Mounteer, Ann H; Bellato, Carlos Roberto; Silva, Laís Miguelina Marçal da; Brant Dias, Santos Henrique; Silva, Priscila Romana da

    2018-04-01

    The objective of this study was to evaluate ADMI color removal from a biologically treated textile mill effluent by heterogeneous photocatalysis with UV-visible irradiation (UV-vis) using a novel catalyst composed of TiO 2 supported on hydrotalcite and doped with iron oxide (HT/Fe/TiO 2 ). Simulated biological treatment of solutions of the dyes (50 mg/L) used in the greatest amounts at the mill where the textile effluent was collected resulted in no color removal in reactive dye solutions and about 50% color removal in vat dye solutions, after 96 h, indicating that the secondary effluent still contained a large proportion of anionic reactive dyes. Photocatalytic treatments were carried out with TiO 2 and HT/Fe/TiO 2 of Fe:Ti molar ratios of 0.25, 0.5, 0.75 and 1, with varying catalyst doses (0-3 mg/L), initial pH values (4-10) and UV-vis times (0-6 h). The highest ADMI color removal with unmodified TiO 2 was found at a dose of 2 g/L and pH 4, an impractical pH value for industrial application. The most efficient composite was HT/Fe/TiO 2 1 at pH 10, also at a dose of 2 g/L, which provided more complete ADMI color removal, from 303 to 9 ADMI color units (96%), than unmodified TiO 2 , from 303 to 37 ADMI color units (88%), under the same conditions. Hydroxyl radicals were responsible for the color reduction, since when 2-propanol, an OH scavenger, was added color removal was very low. For this reason, the HT/Fe/TiO 2 1 composite performed better at pH 10, because the higher concentration of hydroxide ions present at higher pH favored hydroxyl radical formation. COD reductions were relatively low and similar, approximately 20% for both catalysts after 6 h under UV-vis, because of the low initial COD (78 mg/L). Secondary effluent toxicity to Daphnia similis (EC 50  = 70.7%) was reduced by photocatalysis with TiO 2 (EC 50  = 95.0%) and the HT/Fe/TiO 2 1 composite (EC 50  = 78.6%). HT/Fe/TiO 2 1 was reused five times and still lowered

  7. Management of inflammatory bowel disease-related anemia and iron deficiency with specific reference to the role of intravenous iron in current practice.

    Science.gov (United States)

    Stein, Jürgen; Aksan, Ayşegül; Farrag, Karima; Dignass, Axel; Radeke, Heinfried H

    2017-11-01

    Anemia is a common extraintestinal manifestation in patients with inflammatory bowel disease, impacting disease prognosis, morbidity, hospitalization rates and time lost from work. While iron deficiency anemia and anemia of chronic inflammation predominate, combinations of hematimetric and biochemical markers facilitate the diagnosis and targeted therapy of other etiologies according to their underlying pathophysiological causes. Intravenous iron replacement is currently recommended in IBD patients with moderate to severe anemia or intolerance to oral iron. Areas covered: This review examines the impact, pathophysiology and diagnostics of iron deficiency and anemia, compares the characteristics and safety profiles of available oral and intravenous iron preparations, and highlights issues which require consideration in decision making for therapy administration and monitoring. Expert opinion: Modern intravenous iron formulations have been shown to be safe and effective in IBD patients, allowing rapid anemia correction and repletion of iron stores. While traditional oral iron preparations are associated with increased inflammation, negative effects on the microbiome, and poor tolerance and compliance, first clinical trial data indicate that newer oral compounds such as ferric maltol and sucrosomial iron offer improved tolerability and may thus offer a viable alternative for the future.

  8. The role of melatonin on brain iron homeostasis and its relation to Parkinson’s Disease

    OpenAIRE

    Lai, Hien Tet

    2017-01-01

    Parkinson’s Disease (PD) is the second most common neurological disorder after Alzheimer’s Disease. The disease will manifest with the loss of up to 70% of the dopaminergic neurons in the Substantia Nigra (SN) region and it mainly affects the elderly. One of the common pathological hallmarks for PD is the excessive iron accumulation within the SN region of the brain. However, the pathogenesis for of the excessive iron levels accumulation in the SN is unclear. The increase in intracellular oxi...

  9. Hydrothermal synthesis of layered iron-chalcogenide superconductors and related compounds

    International Nuclear Information System (INIS)

    Pachmayr, Ursula Elisabeth

    2017-01-01

    This thesis provides a new preparative approach to iron-chalcogenide based superconductors. The hydrothermal synthesis of anti-PbO type FeSe, which can be seen as basis structure of the compounds of interest was successfully developed. Along with this, some insights regarding the influence of synthesis parameters were gained featuring a basis for further hydrothermal syntheses of new iron-chalcogenide compounds. The potential of this method, primarily the extension of the so far limited accessibility of iron-chalcogenide based superconductors by solid-state sythesis, was revealed within the present work. The solid-solution FeSe_1_-_xS_x was prepared for the whole substitution range, whereas solid-state synthesis exhibits a solubility limit at x = 0.3. Furthermore, the new compounds [(Li_0_._8Fe_0_._2)OH]FeX (X = Se, S) were synthesized which are exclusively accessible via hydrothermal method. The compounds, where layers of (Li_0_._8Fe_0_._2)OH alternate with FeX layers, feature exceptional physical properties, notably a coexistence of superconductivity and ferromagnetism. They were intensively studied within this work. By combination of solid-state and hydrothermal ion-exchange synthesis even large crystals necessary for subsequent physical measurements are accessible. Apart from these layered iron-chalcogenide superconductors, further compounds which likewise exhibit building blocks of edge-sharing FeSe_4 tetrahedra were found via this synthesis method. The iron selenides A_2Fe_4Se_6 (A = K, Rb, Cs) consist of double chains of [Fe_2Se_3]"1"-, whereas a new compound Na_6(H_2O)_1_8Fe_4Se_8 exhibits [Fe_4Se_8]"6"- 'stella quadrangula' clusters. This structural diversity as well as the associated physical properties of the compounds demonstrates the numerous capabilities of hydrothermal synthesis in the field of iron-chalcogenide compounds. In particular with regard to iron-chalcogenide based superconductors this synthesis strategy is encouraging. It seems probable

  10. Hydrothermal synthesis of layered iron-chalcogenide superconductors and related compounds

    Energy Technology Data Exchange (ETDEWEB)

    Pachmayr, Ursula Elisabeth

    2017-04-06

    This thesis provides a new preparative approach to iron-chalcogenide based superconductors. The hydrothermal synthesis of anti-PbO type FeSe, which can be seen as basis structure of the compounds of interest was successfully developed. Along with this, some insights regarding the influence of synthesis parameters were gained featuring a basis for further hydrothermal syntheses of new iron-chalcogenide compounds. The potential of this method, primarily the extension of the so far limited accessibility of iron-chalcogenide based superconductors by solid-state sythesis, was revealed within the present work. The solid-solution FeSe{sub 1-x}S{sub x} was prepared for the whole substitution range, whereas solid-state synthesis exhibits a solubility limit at x = 0.3. Furthermore, the new compounds [(Li{sub 0.8}Fe{sub 0.2})OH]FeX (X = Se, S) were synthesized which are exclusively accessible via hydrothermal method. The compounds, where layers of (Li{sub 0.8}Fe{sub 0.2})OH alternate with FeX layers, feature exceptional physical properties, notably a coexistence of superconductivity and ferromagnetism. They were intensively studied within this work. By combination of solid-state and hydrothermal ion-exchange synthesis even large crystals necessary for subsequent physical measurements are accessible. Apart from these layered iron-chalcogenide superconductors, further compounds which likewise exhibit building blocks of edge-sharing FeSe{sub 4} tetrahedra were found via this synthesis method. The iron selenides A{sub 2}Fe{sub 4}Se{sub 6} (A = K, Rb, Cs) consist of double chains of [Fe{sub 2}Se{sub 3}]{sup 1-}, whereas a new compound Na{sub 6}(H{sub 2}O){sub 18}Fe{sub 4}Se{sub 8} exhibits [Fe{sub 4}Se{sub 8}]{sup 6-} 'stella quadrangula' clusters. This structural diversity as well as the associated physical properties of the compounds demonstrates the numerous capabilities of hydrothermal synthesis in the field of iron-chalcogenide compounds. In particular with regard

  11. Reaction-Based Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center

    International Nuclear Information System (INIS)

    Yeh, Gour-Tsyh

    2006-01-01

    This research project (started Fall 2004) was funded by a grant to The Pennsylvania State University, University of Central Florida, and The University of Alabama in the Integrative Studies Element of the NABIR Program (DE-FG04-ER63914/63915/63196). Dr. Eric Roden, formerly at The University of Alabama, is now at the University of Wisconsin - Madison. Our project focuses on the development of a mechanistic understanding and quantitative models of coupled Fe(III)/U(VI) reduction in FRC Area 2 sediments. This work builds on our previous studies of microbial Fe(III) and U(VI) reduction, and is directly aligned with the Scheibe et al. NABIR FRC Field Project at Area 2

  12. Reduction experiment of FeO-bearing amorphous silicate: application to origin of metallic iron in GEMS

    Energy Technology Data Exchange (ETDEWEB)

    Matsuno, Junya; Tsuchiyama, Akira; Miyake, Akira [Department of Geology and Mineralogy, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502 (Japan); Noguchi, Ryo [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Ichikawa, Satoshi, E-mail: jmatsuno@kueps.kyoto-u.ac.jp [Institute for Nano-science Design, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)

    2014-09-10

    Glass with embedded metal and sulfides (GEMS) are amorphous silicates included in anhydrous interplanetary dust particles (IDPs) and can provide information about material evolution in our early solar system. Several formation processes for GEMS have been proposed so far, but these theories are still being debated. To investigate a possible GEMS origin by reduction of interstellar silicates, we synthesized amorphous silicates with a mean GEMS composition and performed heating experiments in a reducing atmosphere. FeO-bearing amorphous silicates were heated at 923 K and 973 K for 3 hr, and at 1023 K for 1-48 hr at ambient pressure in a reducing atmosphere. Fe grains formed at the interface between the silicate and the reducing gas through a reduction. In contrast, TEM observations of natural GEMS show that metallic grains are uniformly embedded in amorphous silicates. Therefore, the present study suggests that metallic inclusions in GEMS could not form as reduction products and that other formation process such as condensation or irradiation are more likely.

  13. Metal regeneration of iron chelates in nitric oxide scrubbing

    Science.gov (United States)

    Chang, S.G.; Littlejohn, D.; Shi, Y.

    1997-08-19

    The present invention relates to a process of using metal particles to reduce NO to NH{sub 3}. More specifically, the invention concerns an improved process to regenerate iron (II) (CHELATE) by reduction of iron (II) (CHELATE) (NO) complex, which process comprises: (a) contacting an aqueous solution containing iron (II) (CHELATE) (NO) with metal particles at between about 20 and 90 C to reduce NO present, produce ammonia or an ammonium ion, and produce free iron (II) (CHELATE) at a pH of between about 3 and 8. The process is useful to remove NO from flue gas and reduce pollution. 34 figs.

  14. Iron-mediated anaerobic oxidation of methane in brackish coastal sediments.

    Science.gov (United States)

    Egger, Matthias; Rasigraf, Olivia; Sapart, Célia J; Jilbert, Tom; Jetten, Mike S M; Röckmann, Thomas; van der Veen, Carina; Bândă, Narcisa; Kartal, Boran; Ettwig, Katharina F; Slomp, Caroline P

    2015-01-06

    Methane is a powerful greenhouse gas and its biological conversion in marine sediments, largely controlled by anaerobic oxidation of methane (AOM), is a crucial part of the global carbon cycle. However, little is known about the role of iron oxides as an oxidant for AOM. Here we provide the first field evidence for iron-dependent AOM in brackish coastal surface sediments and show that methane produced in Bothnian Sea sediments is oxidized in distinct zones of iron- and sulfate-dependent AOM. At our study site, anthropogenic eutrophication over recent decades has led to an upward migration of the sulfate/methane transition zone in the sediment. Abundant iron oxides and high dissolved ferrous iron indicate iron reduction in the methanogenic sediments below the newly established sulfate/methane transition. Laboratory incubation studies of these sediments strongly suggest that the in situ microbial community is capable of linking methane oxidation to iron oxide reduction. Eutrophication of coastal environments may therefore create geochemical conditions favorable for iron-mediated AOM and thus increase the relevance of iron-dependent methane oxidation in the future. Besides its role in mitigating methane emissions, iron-dependent AOM strongly impacts sedimentary iron cycling and related biogeochemical processes through the reduction of large quantities of iron oxides.

  15. Three-dimensional iron, nitrogen-doped carbon foams as efficient electrocatalysts for oxygen reduction reaction in alkaline solution

    International Nuclear Information System (INIS)

    Ma, Yanjiao; Wang, Hui; Feng, Hanqing; Ji, Shan; Mao, Xuefeng; Wang, Rongfang

    2014-01-01

    Graphical abstract: Three-dimentional Fe, N-doped carbon foams prepared by two steps exhibited comparable catalytic activity for oxygen reduction reaction to commercial Pt/C due to the unique structure and the synergistic effect of Fe and N atoms. - Highlights: • Three-dimensional Fe, N-doped carbon foam (3D-CF) were prepared. • 3D-CF exhibits comparable catalytic activity to Pt/C for oxygen reduction reaction. • The enhanced activity of 3D-CF results of its unique structure. - Abstract: Three-dimensional (3D) Fe, N-doped carbon foams (3D-CF) as efficient cathode catalysts for the oxygen reduction reaction (ORR) in alkaline solution are reported. The 3D-CF exhibit interconnected hierarchical pore structure. In addition, Fe, N-doped carbon without porous strucuture (Fe-N-C) and 3D N-doped carbon without Fe (3D-CF’) are prepared to verify the electrocatalytic activity of 3D-CF. The electrocatalytic performance of as-prepared 3D-CF for ORR shows that the onset potential on 3D-CF electrode positively shifts about 41 mV than those of 3D-CF’ and Fe-N-C respectively. In addition, the onset potential on 3D-CF electrode for ORR is about 27 mV more negative than that on commercial Pt/C electrode. 3D-CF also show better methanol tolerance and durability than commercial Pt/C catalyst. These results show that to synthesize 3D hierarchical pores with high specific surface area is an efficient way to improve the ORR performance

  16. Iron and sulfur geochemistry in semi-arid mangrove soils (Ceará, Brazil) in relation to seasonal changes and shrimp farming effluents.

    Science.gov (United States)

    Nóbrega, G N; Ferreira, T O; Romero, R E; Marques, A G B; Otero, X L

    2013-09-01

    Iron and sulfur are key elements in the biogeochemistry of estuarine soils, in which Fe and sulfate reduction (SR) pathways are important for organic matter decomposition. In the semi-arid coast of NE Brazil, mangroves are characterized by large seasonal variations in weather and the presence of numerous shrimp farms. The objective was to determine the impacts of shrimp farm effluents on iron and sulfur geochemistry in mangrove soils under the semi-arid climate of NE Brazil. A seasonal study was made of two mangrove forest soils (SF, a mangrove forest that directly receives wastewater from shrimp ponds and CS, a control site). Pyrite Fe, oxyhydroxides Fe, acid volatile sulfide, degree of pyritization (DOP), pH, Eh, total organic carbon (TOC) and total S were determined. There was a clear decrease in pyritic Fe and DOP in the SF soils, which may be related to the anaerobic oxidation of pyrite coupled with nitrate reduction, or to the dominance of denitrification over SR. Lower TOC contents in the SF site suggest that below ground decomposition increased in response to eutrophication. The seasonal variations led to important changes in the semi-arid mangrove soils. During the dry period, both soils experienced oxidizing conditions with remarkable loss of reduced and oxidized forms of Fe, which may have important environmental implications as Fe is biolimiting for marine primary production. The data show that both factors (seasonal weather variations and shrimp effluents) play important roles in the geochemical processes that occur in these soils and, thus, may affect their functioning and maintenance.

  17. NF ISO 7097-1. Nuclear fuel technology - Uranium dosimetry in solutions, in uranium hexafluoride and in solids - Part 1: reduction with iron (II) / oxidation with potassium bi-chromate / titration method

    International Nuclear Information System (INIS)

    2002-04-01

    This standard document describes the mode of operation of three different methods for the quantitative dosimetry of uranium in solutions, in UF 6 and in solids: reduction by iron (II), oxidation by potassium bi-chromate and titration. (J.S.)

  18. Effect of the addition of zero valent iron (Fe0) on the batch biological sulphate reduction using grass cellulose as carbon source

    CSIR Research Space (South Africa)

    Mulopo, J

    2013-09-01

    Full Text Available of grass cuttings and iron filings. Reactors A and B received twice as much grass (100 g) as C (50 g). Reactor A received no iron filings to act as a control, while reactors B and C received 50-g iron filings for the experimental duration. The results...

  19. Selective catalytic reduction of NO{sub x} with NH{sub 3} over iron-cerium-tungsten mixed oxide catalyst prepared by different methods

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Zhi-bo, E-mail: xzb328@163.com [School of Energy and Power Engineering, University of Shanghai for Science & Technology, Shanghai 200093 (China); Collaborative Innovation Research Institute, University of Shanghai for Science & Technology, Shanghai 200093 (China); Shanghai Power Equipment Research Institute, Shanghai 200240 (China); Liu, Jing; Zhou, Fei; Liu, Dun-yu; Lu, Wei [School of Energy and Power Engineering, University of Shanghai for Science & Technology, Shanghai 200093 (China); Jin, Jing [School of Energy and Power Engineering, University of Shanghai for Science & Technology, Shanghai 200093 (China); Collaborative Innovation Research Institute, University of Shanghai for Science & Technology, Shanghai 200093 (China); Ding, Shi-fa [Shanghai Power Equipment Research Institute, Shanghai 200240 (China)

    2017-06-01

    Highlights: • Iron-cerium-tungsten mixed oxide catalysts were prepared through three different methods. • The effect of preparation methods on the NH{sub 3}-SCR activity and the surface structure properties of catalyst were investigated. • Iron-cerium-tungsten mixed oxide prepared through microwave irradiation assistant critic acid sol-gel shows higher NH{sub 3}-SCR activity. - Abstract: A series of magnetic Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z} catalysts were synthesized by three different methods(Co-precipitation(Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-CP), Hydrothermal treatment assistant critic acid sol-gel method(Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-HT) and Microwave irradiation assistant critic acid sol-gel method(Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-MW)), and the catalytic activity was evaluated for selective catalytic reduction of NO with NH{sub 3}. The catalyst was characterized by XRD, N{sub 2} adsorption-desorption, XPS, H{sub 2}-TPR and NH{sub 3}-TPD. Among the tested catalysts, Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-MW shows the highest NO{sub x} conversion over per gram in unit time with NO{sub x} conversion of 60.8% at 350 °C under a high gas hourly space velocity of 1,200,000 ml/(g h). Different from Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-CP catalyst, there exists a large of iron oxide crystallite(γ-Fe{sub 2}O{sub 3} and α-Fe{sub 2}O{sub 3}) scattered in Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z} catalysts prepared through hydrothermal treatment or microwave irradiation assistant critic acid sol-gel method, and higher iron atomic concentration on their surface. And Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-MW shows higher surface absorbed oxygen concentration and better dispersion compared with Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-HT catalyst. These features were favorable for the high catalytic performance of NO reduction with NH{sub 3} over Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-MW catalyst.

  20. 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

    Cl2 solution into the column, an ion distribution pattern was observed in the effluent that suggests the formation of separate reaction fronts for Mn(III)-oxide and Mn(IV)-oxide travelling at different velocities through the column. At the proximal reaction front, Fe21 reacts with MnO2 producing Fe......The reduction of Mn-oxide by Fe21 was studied in column experiments, using a column filled with natural Mn-oxide coated sand. Analysis of the Mn-oxide indicated the presence of both Mn(III) and Mn(IV) in the Mn-oxide. The initial exchange capacity of the column was determined by displacement...... of adsorbed Ca21 with Mg21. Subsequently a FeCl2 solution was injected into the column causing the reduction of the Mn-oxide and the precipitation of Fe(OH)3. Finally the exchange capacity of the column containing newly formed Fe(OH)3 was determined by injection of a KBr solution. During injection of the Fe...

  1. Duodenal Cytochrome b (DCYTB in Iron Metabolism: An Update on Function and Regulation

    Directory of Open Access Journals (Sweden)

    Darius J. R. Lane

    2015-03-01

    Full Text Available Iron and ascorbate are vital cellular constituents in mammalian systems. The bulk-requirement for iron is during erythropoiesis leading to the generation of hemoglobin-containing erythrocytes. Additionally; both iron and ascorbate are required as co-factors in numerous metabolic reactions. Iron homeostasis is controlled at the level of uptake; rather than excretion. Accumulating evidence strongly suggests that in addition to the known ability of dietary ascorbate to enhance non-heme iron absorption in the gut; ascorbate regulates iron homeostasis. The involvement of ascorbate in dietary iron absorption extends beyond the direct chemical reduction of non-heme iron by dietary ascorbate. Among other activities; intra-enterocyte ascorbate appears to be involved in the provision of electrons to a family of trans-membrane redox enzymes; namely those of the cytochrome b561 class. These hemoproteins oxidize a pool of ascorbate on one side of the membrane in order to reduce an electron acceptor (e.g., non-heme iron on the opposite side of the membrane. One member of this family; duodenal cytochrome b (DCYTB; may play an important role in ascorbate-dependent reduction of non-heme iron in the gut prior to uptake by ferrous-iron transporters. This review discusses the emerging relationship between cellular iron homeostasis; the emergent “IRP1-HIF2α axis”; DCYTB and ascorbate in relation to iron metabolism.

  2. Degradação redutiva de azo-corantes utilizando-se ferro metálico Reductive degradation of azo-dyes by metallic iron

    Directory of Open Access Journals (Sweden)

    Cláudio Lima de Souza

    2006-03-01

    Full Text Available Corantes azo são extensivamente utilizados em processos de tingimento de fibras têxteis, sendo caracterizados por elevada resistência frente a processos aeróbios de biodegradação e, por conseqüência, persistência nos processos convencionais de tratamento de resíduos. Neste trabalho reporta-se a degradação redutiva de corantes azo, utilizando-se ferro metálico. Em condições experimentais otimizadas (pH 7 e 10 g de lã de aço comercial a completa descoloração do corante modelo (preto reativo 5 foi conseguida em um sistema contínuo, operando com tempos de retenção de 6 min. Nestas condições, o ferro solubilizado alcança concentrações compatíveis com os limites impostos pela atual legislação brasileira (12 mg L-1. Trata-se de um resultado bastante promissor, principalmente levando-se em consideração o caráter recalcitrante dos azo corantes e a simplicidade do sistema proposto.Azo dyes are extensively used in textile dying processes and are characterized by extreme resistance to biodegradation and consequently persistence during conventional wastewater treatment processes. In this work the reductive degradation of azo dyes was studied using zero-valent iron. At optimized experimental conditions (pH 7 and 10 g of commercial iron wool complete decolorization of the model dye (reactive black 5 was afforded in a continuous system operating with hydraulic retention time of 6 min. At these conditions the released total soluble iron reaches a concentration compatible with the limits imposed by the current Brazilian legislation (12 mg L-1. That is a very promising result, mainly taking into account the high recalcitrant character of azo dyes and the simplicity of the proposed system.

  3. Oxidation and reduction of copper and iron species in steam generator deposits - Effects of hydrazine, carbohydrazide and catalyzed hydrazine

    International Nuclear Information System (INIS)

    Marks, C.R.; Varrin, R.D.; Gorman, J.A.; McIlree, A.R.; Stanley, R.

    2002-01-01

    It has long been suspected that oxidation and reduction of secondary side deposits in PWR steam generators have a significant influence on the onset of intergranular attack and stress corrosion cracking (IGA/SCC) of mill annealed Alloy 600 steam generator tubes. It is believed that these same processes could affect the possible future occurrence of IGA/SCC of thermally treated Alloy 600 and Alloy 690 tubes that are in newer steam generators. The working hypothesis for describing the influence of oxides on accelerated tube degradation is that deposits formed during normal operation are oxidized during lay-up. During subsequent operation, these oxidized species accelerate tube degradation by raising the electrochemical potential. (authors)

  4. Effectiveness of fortification of drinking water with iron and vitamin C in the reduction of anemia and improvement of nutritional status in children attending day-care centers in Belo Horizonte, Brazil.

    Science.gov (United States)

    Rocha, Daniela da Silva; Capanema, Flávio Diniz; Netto, Michele Pereira; de Almeida, Carlos Alberto Nogueira; Franceschini, Sylvia do Carmo Castro; Lamounier, Joel Alves

    2011-12-01

    Because of the high prevalence of iron-deficiency anemia in Brazil, individual control measures tend to be ineffective, and fortification of foods with iron is considered the most effective method to fight anemia. To evaluate the effectiveness of fortification of drinking water with iron and vitamin C in the reduction of anemia in children in day-care centers in Belo Horizonte, Brazil. This before-and-after study evaluated 318 children aged 6 to 74 months. Identification data and data on socioeconomic variables were collected; anthropometric and biochemical measurements were performed before and after 5 months of fortification of water with 5 mg of elemental iron and 50 mg of ascorbic acid per liter. The fortified water was used for drinking and cooking at the day-care center. Wilcoxon's nonparametric test was used to evaluate the differences in continuous variables, and McNemar's test was used to compare the prevalence rates of anemia. The prevalence of anemia decreased significantly from 29.3% before fortification to 7.9% at the end of the study, with a significant increase in hemoglobin levels. Reductions in the prevalence rates of stunting and underweight were observed. Fortification of water with iron and vitamin C significantly reduced the prevalence of anemia and improved nutritional status among children attending day-care centers.

  5. Iron absorption studies

    International Nuclear Information System (INIS)

    Ekenved, G.

    1976-01-01

    The main objective of the present work was to study iron absorption from different iron preparations in different types of subjects and under varying therapeutic conditions. The studies were performed with different radioiron isotope techniques and with a serum iron technique. The preparations used were solutions of ferrous sulphate and rapidly-disintegrating tablets containing ferrous sulphate, ferrous fumarate and ferrous carbonate and a slow-release ferrous sulphate tablet of an insoluble matrix type (Duroferon Durules). The serum iron method was evaluated and good correlation was found between the serum iron response and the total amount of iron absorbed after an oral dose of iron given in solution or in tablet form. New technique for studying the in-vivo release properties of tablets was presented. Iron tablets labelled with a radio-isotope were given to healthy subjects. The decline of the radioactivity in the tablets was followed by a profile scanning technique applied to different types of iron tablets. The release of iron from the two types of tablets was shown to be slower in vivo than in vitro. It was found that co-administration of antacids and iron tablets led to a marked reduction in the iron absorption and that these drugs should not be administered sumultaneously. A standardized meal markedly decreased the absorbability of iron from iron tablets. The influence of the meal was more marked with rapidly-disintegrating than with slow-release ferrous sulphate tablets. The absorption from rapidly-disintegrating and slow-release ferrous sulphate tablets was compared under practical clinical conditions during an extended treatment period. The studies were performed in healthy subjects, blood donors and patients with iron deficiency anaemia and it was found that the absorption of iron from the slow-release tablets was significantly better than from the rapidly-disintegrating tablets in all three groups of subjects. (author)

  6. Reductive dechlorination of 3,3',4,4'-tetrachlorobiphenyl (PCB77) using palladium or palladium/iron nanoparticles and assessment of the reduction in toxic potency in vascular endothelial cells

    International Nuclear Information System (INIS)

    Venkatachalam, Karthik; Arzuaga, Xabier; Chopra, Nitin; Gavalas, Vasilis G.; Xu, Jian; Bhattacharyya, Dibakar; Hennig, Bernhard; Bachas, Leonidas G.

    2008-01-01

    Palladium-based nanoparticles immobilized in polymeric matrices were applied to the reductive dechlorination of 3,3',4,4'-tetrachlorobiphenyl (PCB77) at room temperature. Two different dechlorination platforms were evaluated using (1) Pd nanoparticles within conductive polypyrrole films; or (2) immobilized Fe/Pd nanoparticles within polyvinylidene fluoride microfiltration membranes. For the first approach, the polypyrrole film was electrochemically formed in the presence of perchlorate ions that were incorporated into the film to counter-balance the positive charges of the polypyrrole chain. The film was then incubated in a solution containing tetrachloropalladate ions, which were exchanged with the perchlorate ions within the film. During this exchange, reduction of tetrachloropalladate by polypyrrole occurred, which led to the formation of palladium nanoparticles within the film. For the second approach, the membrane-supported Fe/Pd nanoparticles were prepared in three steps: polymerization of acrylic acid in polyvinylidene fluoride microfiltration membrane pores was followed by ion exchange of Fe 2+ , and then chemical reduction of the ferrous ions bound to the carboxylate groups. The membrane-supported iron nanoparticles were then soaked in a solution of tetrachloropalladate resulting in the deposition of Pd on the Fe surface. The nanoparticles prepared by both approaches were employed in the dechlorination of PCB77. The presence of hydrogen was required when the monometallic Pd nanoparticles were employed. The results indicate the removal of chlorine atoms from PCB77, which led to the formation of lower chlorinated intermediates and ultimately biphenyl. Toxicity associated with vascular dysfunction by PCB77 and biphenyl was compared using cultured endothelial cells. The data strongly suggest that the dechlorination system used in this study markedly reduced the proinflammatory activity of PCB77, a persistent organic pollutant

  7. A highly efficient electrocatalyst for oxygen reduction reaction: phosphorus and nitrogen co-doped hierarchically ordered porous carbon derived from an iron-functionalized polymer

    Science.gov (United States)

    Deng, Chengwei; Zhong, Hexiang; Li, Xianfeng; Yao, Lan; Zhang, Huamin

    2016-01-01

    Heteroatom-doped carbon materials have shown respectable activity for the oxygen reduction reaction (ORR) in alkaline media. However, the performances of these materials are not satisfactory for energy conversion devices, such as fuel cells. Here, we demonstrate a new type of phosphorus and nitrogen co-doped hierarchically ordered porous carbon (PNHOPC) derived from an iron-functionalized mesoporous polymer through an evaporation-induced self-assembly process that simultaneously combines the carbonization and nitrogen doping processes. The soft template and the nitrogen doping process facilitate the formation of the hierarchically ordered structure for the PNHOPC. The catalyst possesses a large surface area (1118 cm2 g-1) and a pore volume of 1.14 cm3 g-1. Notably, it exhibits excellent ORR catalytic performance, superior stability and methanol tolerance in acidic electrolytes, thus making the catalyst promising for fuel cells. The correlations between the unique pore structure and the nitrogen and phosphorus configuration of the catalysts with high catalytic activity are thoroughly investigated.Heteroatom-doped carbon materials have shown respectable activity for the oxygen reduction reaction (ORR) in alkaline media. However, the performances of these materials are not satisfactory for energy conversion devices, such as fuel cells. Here, we demonstrate a new type of phosphorus and nitrogen co-doped hierarchically ordered porous carbon (PNHOPC) derived from an iron-functionalized mesoporous polymer through an evaporation-induced self-assembly process that simultaneously combines the carbonization and nitrogen doping processes. The soft template and the nitrogen doping process facilitate the formation of the hierarchically ordered structure for the PNHOPC. The catalyst possesses a large surface area (1118 cm2 g-1) and a pore volume of 1.14 cm3 g-1. Notably, it exhibits excellent ORR catalytic performance, superior stability and methanol tolerance in acidic

  8. Platinum Iron Intermetallic Nanoparticles Supported on Carbon Formed In Situ by High-Pressure Pyrolysis for Efficient Oxygen Reduction

    DEFF Research Database (Denmark)

    Hu, Yang; Jensen, Jens Oluf; Zhang, Wei

    2016-01-01

    Carbon-supported PtFe alloy catalysts are synthesized by the one-step, high-temperature pyrolysis of Pt, Fe, and C precursors. As a result of the high temperature, the formed PtFe nanoparticles possess highly ordered, face-centered tetragonal, intermetallic structures with a mean size of ≈11.8 nm....... At 0.9 V versus the reversible hydrogen electrode, the PtFe nanoparticles show a 6.8 times higher specific activity than the reference Pt/C catalyst towards the oxygen reduction reaction (ORR) as well as excellent stability, most likely because of the durable intermetallic structure and the preleaching...... treatment of the catalyst. During these preliminary syntheses, we found that a portion of the PtFe nanoparticles is buried in the in situ formed carbon phase, which limits Pt utilization in the catalyst and results in a mass-specific activity equivalent to the commercial Pt/C catalyst. Moreover...

  9. Review of CO2 Reduction Technologies using Mineral Carbonation of Iron and Steel Making Slag in Malaysia

    Science.gov (United States)

    Norhana Selamat, Siti; Nor, Nik Hisyamudin Muhd; Rashid, Muhammad Hanif Abdul; Fauzi Ahmad, Mohd; Mohamad, Fariza; Ismail, Al Emran; Fahrul Hassan, Mohd; Turan, Faiz Mohd; Zain, Mohd Zamzuri Mohd; Abu Bakar, Elmi; Seiji, Yokoyama

    2017-10-01

    Climate change, greenhouse gas effect, and global warming is envisioning to turn more awful and more terrible by year. Since the leading cause of global warming is uncontrolled CO2 in atmosphere. The amount of unused steel slag is expected to increment later on, steel industries is one of the mechanical industries that contribute the CO2 emission. That because this businesses deliver carbon in light of powers reductant and substantial volume of steel. The changes of atmosphere these day is truly developing concern and that make steel creator are confronted with test of discovering methods for bringing down CO2 emission. Malaysia is working decidedly in the diminishment of CO2 gas. There are a few techniques in decreasing the amount of CO2 in the air as underlined by the Intergovernmental Panel of Climate Change (IPCC), an organization under the United Country however CCS is an extremely encouraging innovation to moderate CO2 emission in air. Mineral carbonation is another technique to store carbon dioxide permanently, long term stability and vast capacity.

  10. 49 CFR 192.487 - Remedial measures: Distribution lines other than cast iron or ductile iron lines.

    Science.gov (United States)

    2010-10-01

    ... cast iron or ductile iron lines. 192.487 Section 192.487 Transportation Other Regulations Relating to... iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe, each... the purpose of this paragraph. (b) Localized corrosion pitting. Except for cast iron or ductile iron...

  11. Alcoholism Risk Reduction in France: A Modernised Approach Related to Alcohol Misuse Disorders

    Directory of Open Access Journals (Sweden)

    Georges Brousse

    2014-11-01

    Full Text Available During many years in France, risk reduction strategies for substance abuse concerned prevention strategies in the general population or interventions near users of illicit substances. In this spirit, the reduction of consumption only concerned opiate addicts. With regard to alcohol, the prevention messages relative to controlled consumption were difficult to transmit because of the importance of this product in the culture of the country. In addition, methods of treatment of alcoholism rested on the dogma of abstinence. Several factors have recently led to an evolution in the treatment of alcohol use disorders integrating the reduction of consumption in strategies. Strategies for reducing consumption should aim for consumption below recommended thresholds (two drinks per day for women, three for the men or, at least, in that direction. It must also be supported by pharmacotherapy and psychotherapy, which offer possibilities. Failure to manage reduction will allow the goals to be revisited and to reconsider abstinence. Finally this evolution or revolution is a new paradigm carried in particular by a pragmatic approach of the disease and new treatments. The aims of this article are to give elements of comprehension relating to the evolution of the practices in France in prevention and treatment of alcohol use disorders and in particular with regard to the reduction of consumption.

  12. Reductive reactivity of iron(III) oxides in the east china sea sediments: characterization by selective extraction and kinetic dissolution.

    Science.gov (United States)

    Chen, Liang-Jin; Zhu, Mao-Xu; Yang, Gui-Peng; Huang, Xiang-Li

    2013-01-01

    Reactive Fe(III) oxides in gravity-core sediments collected from the East China Sea inner shelf were quantified by using three selective extractions (acidic hydroxylamine, acidic oxalate, bicarbonate-citrate buffered sodium dithionite). Also the reactivity of Fe(III) oxides in the sediments was characterized by kinetic dissolution using ascorbic acid as reductant at pH 3.0 and 7.5 in combination with the reactive continuum model. Three parameters derived from the kinetic method: m 0 (theoretical initial amount of ascorbate-reducible Fe(III) oxides), k' (rate constant) and γ (heterogeneity of reactivity), enable a quantitative characterization of Fe(III) oxide reactivity in a standardized way. Amorphous Fe(III) oxides quantified by acidic hydroxylamine extraction were quickly consumed in the uppermost layer during early diagenesis but were not depleted over the upper 100 cm depth. The total amounts of amorphous and poorly crystalline Fe(III) oxides are highly available for efficient buffering of dissolved sulfide. As indicated by the m 0, k' and γ, the surface sediments always have the maximum content, reactivity and heterogeneity of reactive Fe(III) oxides, while the three parameters simultaneously downcore decrease, much more quickly in the upper layer than at depth. Albeit being within a small range (within one order of magnitude) of the initial rates among sediments at different depths, incongruent dissolution could result in huge discrepancies of the later dissolution rates due to differentiating heterogeneity, which cannot be revealed by selective extraction. A strong linear correlation of the m 0 at pH 3.0 with the dithionite-extractable Fe(III) suggests that the m 0 may represent Fe(III) oxide assemblages spanning amorphous and crystalline Fe(III) oxides. Maximum microbially available Fe(III) predicted by the m 0 at pH 7.5 may include both amorphous and a fraction of other less reactive Fe(III) phases.

  13. Iron isotope biogeochemistry of Neoproterozoic marine shales

    Science.gov (United States)

    Kunzmann, Marcus; Gibson, Timothy M.; Halverson, Galen P.; Hodgskiss, Malcolm S. W.; Bui, Thi Hao; Carozza, David A.; Sperling, Erik A.; Poirier, André; Cox, Grant M.; Wing, Boswell A.

    2017-07-01

    Iron isotopes have been widely applied to investigate the redox evolution of Earth's surface environments. However, it is still unclear whether iron cycling in the water column or during diagenesis represents the major control on the iron isotope composition of sediments and sedimentary rocks. Interpretation of isotopic data in terms of oceanic redox conditions is only possible if water column processes dominate the isotopic composition, whereas redox interpretations are less straightforward if diagenetic iron cycling controls the isotopic composition. In the latter scenario, iron isotope data is more directly related to microbial processes such as dissimilatory iron reduction. Here we present bulk rock iron isotope data from late Proterozoic marine shales from Svalbard, northwestern Canada, and Siberia, to better understand the controls on iron isotope fractionation in late Proterozoic marine environments. Bulk shales span a δ 56Fe range from -0.45 ‰ to +1.04 ‰ . Although δ 56Fe values show significant variation within individual stratigraphic units, their mean value is closer to that of bulk crust and hydrothermal iron in samples post-dating the ca. 717-660 Ma Sturtian glaciation compared to older samples. After correcting for the highly reactive iron content in our samples based on iron speciation data, more than 90% of the calculated δ 56Fe compositions of highly reactive iron falls in the range from ca. -0.8 ‰ to +3 ‰ . An isotope mass-balance model indicates that diagenetic iron cycling can only change the isotopic composition of highly reactive iron by control the isotopic composition of highly reactive iron. Considering a long-term decrease in the isotopic composition of the iron source to the dissolved seawater Fe(II) reservoir to be unlikely, we offer two possible explanations for the Neoproterozoic δ 56Fe trend. First, a decreasing supply of Fe(II) to the ferrous seawater iron reservoir could have caused the reservoir to decrease in size

  14. Effect of dissimilatory iron and sulfate reduction on arsenic dynamics in the wetland rhizosphere and its bioaccumulation in plants

    Science.gov (United States)

    Jaffe, P. R.; Zhang, Z.; Moon, H. S.; Myneni, S.

    2015-12-01

    The mobility of arsenic in soils is linked to biogeochemical redox processes. The presence of wetland plants in riparian wetlands has a significant impact on the biogeochemical dynamics of the soil/sediment-redoxcline due to the release of root exudates and root turnover and oxygen transfer from the roots into the surrounding sediment. Micro-environmental redox conditions in the rhizosphere affect As, Fe, and S speciation as well as Fe(III) plaque deposition, which affects arsenic transport and uptake by plants. To investigate the dynamics of As coupled to S and Fe cycling in wetlands, mesocosms were operated in a greenhouse under various conditions (high and low Fe, high and low sulfate, with plant and without plants) for four months. Results show that the presence of plants, high Fe, and high SO42- levels enhanced As sequestration in these soils. We hypothesize that this compounding effect is because plants release biodegradable organic carbon, which is used by microorganism to reduce ferrihydrite and SO42- to generate FeS, FeS2, and/or orpiment (As2S3). Over the concentration range studied, As immobilization in soil and uptake by Scirpus actus was mainly controlled by SO42- rather than Fe levels. Under high sulfate levels, As immobilization in soil increased by 50% and As concentrations in plant roots increased by 97%, whereas no significant changes in plant As levels were seen for varying Fe concentrations. More than 80% of As was sequestrated in soils rather than plant uptake. Pore water As speciation analyses indicate that 20% more As(V) was reduced to As(III) under high sulfate as than low sulfate levels and that low Fe was more favorable to the As dissimilatory reduction. More dissimilatory arsenate-respiring bacteria (DARB) under high sulfate were confirmed by quantitative PCR. Arsenic distribution in plant leafs and roots after 30 days of exposure to As was analyzed via Synchrotron X-ray fluorescence analyses. The uptake of As by plants was distributed

  15. Pretreatment of 2,4-dinitroanisole (DNAN) producing wastewater using a combined zero-valent iron (ZVI) reduction and Fenton oxidation process

    International Nuclear Information System (INIS)

    Shen, Jinyou; Ou, Changjin; Zhou, Zongyuan; Chen, Jun; Fang, Kexiong; Sun, Xiuyun; Li, Jiansheng; Zhou, Lin; Wang, Lianjun

    2013-01-01

    Highlights: • ZVI-Fenton process was conducted for DNAN producing wastewater pretreatment. • Transformation of nitro to amino group by ZVI overcomes the oxidative hindrance. • Subsequent Fenton process is efficient for the removal of aromatic compounds. • ABR-MBBR process is efficient for the polishing of ZVI-Fenton effluent. -- Abstract: A combined zero-valent iron (ZVI) reduction and Fenton oxidation process was tested for the pretreatment of 2,4-dinitroanisole (DNAN) producing wastewater. Operating conditions were optimized and overall performance of the combined process was evaluated. For ZVI process, almost complete reduction of nitroaromatic compounds was observed at empty bed contact time (EBCT) of 8 h. For Fenton process, the optimal pH, H 2 O 2 to Fe(II) molar ratio, H 2 O 2 dosage and hydraulic retention time (HRT) were found to be 3.0, 15, 0.216 mol/L and 5 h, respectively. After pretreatment by the combined ZVI-Fenton process under the optimal conditions, aromatic organic compound removal was as high as 77.2%, while the majority of COD remained to be further treated by sequent biological process. The combined anaerobic-aerobic process consisted of an anaerobic baffled reactor (ABR) and a moving-bed biofilm reactor (MBBR) was operated for 3 months, fed with ZVI-Fenton effluent. The results revealed that the coupled ZVI-Fenton-ABR-MBBR system was significantly efficient in terms of correcting the effluent's main parameters of relevance, mainly aromatic compounds concentration, COD concentration, color and acute toxicity. These results indicate that the combined ZVI-Fenton process offers bright prospects for the pretreatment of wastewater containing nitroaromatic compounds

  16. Surface Modification of Multi-Walled Carbon Nanotubes via Hemoglobin-Derived Iron and Nitrogen-Rich Carbon Nanolayers for the Electrocatalysis of Oxygen Reduction

    Directory of Open Access Journals (Sweden)

    Wensheng Li

    2017-05-01

    Full Text Available The great challenge of boosting the oxygen reduction reaction (ORR activity of non-noble-metal electrocatalysts is how to achieve effective exposure and full utilization of nitrogen-rich active sites. To realize the goals of high utilization of active sites and fast electron transport, here we report a new strategy for synthesis of an iron and nitrogen co-doped carbon nanolayers-wrapped multi-walled carbon nanotubes as ORR electrocatalyst (N-C@CNT-Fe via using partially carbonized hemoglobin as a single-source precursor. The onset and half-wave potentials for ORR of N-C@CNT-Fe are only 45 and 54 mV lower than those on a commercial Pt/C (20 wt.% Pt catalyst, respectively. Besides, this catalyst prepared in this work has been confirmed to follow a four-electron reaction mechanism in ORR process, and also displays ultra-high electrochemical cycling stability in both acidic and alkaline electrolytes. The enhancement of ORR activity can be not only attributed to full exposure and utilization of active site structures, but also can be resulted from the improvement of electrical conductivity owing to the introduction of CNT support. The analysis of X-ray photoelectric spectroscopy shows that both Fe–N and graphitic-N species may be the ORR active site structures of the prepared catalyst. Our study can provide a valuable idea for effective improvement of the electrocatalytic activity of non-noble-metal ORR catalysts.

  17. Chemical fingerprint of iron oxides related to iron enrichment of banded iron formation from the Cauê Formation - Esperança Deposit, Quadrilátero Ferrífero, Brazil: a laser ablation ICP-MS study

    Directory of Open Access Journals (Sweden)

    Lucilia Aparecida Ramos de Oliveira

    Full Text Available Chemical signatures of iron oxides from dolomitic itabirite and high-grade iron ore from the Esperança deposit, located in the Quadrilátero Ferrífero, indicate that polycyclic processes involving changing of chemical and redox conditions are responsible for the iron enrichment on Cauê Formation from Minas Supergroup. Variations of Mn, Mg and Sr content in different generations of iron oxides from dolomitic itabirite, high-grade iron ore and syn-mineralization quartz-carbonate-hematite veins denote the close relationship between high-grade iron ore formation and carbonate alteration. This indicates that dolomitic itabirite is the main precursor of the iron ore in that deposit. Long-lasting percolation of hydrothermal fluids and shifts in the redox conditions have contributed to changes in the Y/Ho ratio, light/heavy rare earth elements ratio and Ce anomaly with successive iron oxide generations (martite-granular hematite, as well as lower abundance of trace elements including rare earth elements in the younger specularite generations.

  18. Glutathione, Glutaredoxins, and Iron.

    Science.gov (United States)

    Berndt, Carsten; Lillig, Christopher Horst

    2017-11-20

    Glutathione (GSH) is the most abundant cellular low-molecular-weight thiol in the majority of organisms in all kingdoms of life. Therefore, functions of GSH and disturbed regulation of its concentration are associated with numerous physiological and pathological situations. Recent Advances: The function of GSH as redox buffer or antioxidant is increasingly being questioned. New functions, especially functions connected to the cellular iron homeostasis, were elucidated. Via the formation of iron complexes, GSH is an important player in all aspects of iron metabolism: sensing and regulation of iron levels, iron trafficking, and biosynthesis of iron cofactors. The variety of GSH coordinated iron complexes and their functions with a special focus on FeS-glutaredoxins are summarized in this review. Interestingly, GSH analogues that function as major low-molecular-weight thiols in organisms lacking GSH resemble the functions in iron homeostasis. Since these iron-related functions are most likely also connected to thiol redox chemistry, it is difficult to distinguish between mechanisms related to either redox or iron metabolisms. The ability of GSH to coordinate iron in different complexes with or without proteins needs further investigation. The discovery of new Fe-GSH complexes and their physiological functions will significantly advance our understanding of cellular iron homeostasis. Antioxid. Redox Signal. 27, 1235-1251.

  19. On the relation between reduced quantisation and quantum reduction for spherical symmetry in loop quantum gravity

    International Nuclear Information System (INIS)

    Bodendorfer, N; Zipfel, A

    2016-01-01

    Building on a recent proposal for a quantum reduction to spherical symmetry from full loop quantum gravity, we investigate the relation between a quantisation of spherically symmetric general relativity and a reduction at the quantum level. To this end, we generalise the previously proposed quantum reduction by dropping the gauge fixing condition on the radial diffeomorphisms, thus allowing us to make direct contact with previous work on reduced quantisation. A dictionary between spherically symmetric variables and observables with respect to the reduction constraints in the full theory is discussed, as well as an embedding of reduced quantum states to a subsector of the quantum symmetry reduced full theory states. On this full theory subsector, the quantum algebra of the mentioned observables is computed and shown to qualitatively reproduce the quantum algebra of the reduced variables in the large quantum number limit for a specific choice of regularisation. Insufficiencies in recovering the reduced algebra quantitatively from the full theory are attributed to the oversimplified full theory quantum states we use. (paper)

  20. Hypoadiponectinemia, elevated iron and high-sensitivity C-reactive protein levels and their relation with prostate size in benign prostatic hyperplasia.

    Science.gov (United States)

    Nandeesha, H; Eldhose, A; Dorairajan, L N; Anandhi, B

    2017-09-01

    Elevated iron, high-sensitivity C-reactive protein (CRP) and hypoadiponectinemia are known to initiate tumour development. There is paucity of data regarding the above-mentioned parameters and their relation with prostate size in benign prostatic hyperplasia (BPH). The present study was designed to assess the levels of iron, hs-CRP and adiponectin levels and their association with prostate size in BPH patients. A total of 37 BPH cases and 36 controls were enrolled in the study. Iron, hs-CRP and adiponectin were estimated in both the groups. Iron and hs-CRP were significantly increased and adiponectin was significantly reduced in BPH cases when compared with controls. Iron (r = .397, p = .015), hs-CRP (r = .341, p = .039) and adiponectin (r = -.464, p = .004) were significantly associated with prostate size in BPH cases. Multivariate linear regression analysis showed that iron acts as predictor of prostate size in BPH (R 2  = 0.395, β = 0.526, p = .001). We conclude that iron and hs-CRP are elevated and adiponectin is reduced in BPH cases and associated with prostate size. © 2016 Blackwell Verlag GmbH.

  1. A budget impact analysis of parenteral iron treatments for iron deficiency anemia in the UK: reduced resource utilization with iron isomaltoside 1000

    Directory of Open Access Journals (Sweden)

    Pollock RF

    2017-08-01

    Full Text Available Richard F Pollock,1 Gorden Muduma2 1Ossian Health Economics and Communications GmbH, Basel, Switzerland; 2Pharmacosmos A/S, Holbaek, Denmark Background and aims: The reported prevalence of iron deficiency anemia (IDA varies widely but estimates suggest that 3% of men and 8% of women have IDA in the UK. Parenteral iron is indicated for patients intolerant or unresponsive to oral iron or requiring rapid iron replenishment. This study evaluated differences in the cost of treating these patients with iron isomaltoside (Monofer®, IIM relative to other intravenous iron formulations. Methods: A budget impact model was developed to evaluate the cost of using IIM relative to ferric carboxymaltose (Ferinject®, FCM, low molecular weight iron dextran (Cosmofer®, LMWID, and iron sucrose (Venofer®, IS in patients with IDA. To establish iron need, iron deficits were modeled using a simplified dosing table. The base case analysis was conducted over 1 year in patients with IDA with mean bodyweight of 82.4 kg (SD 22.5 kg and hemoglobin levels of 9.99 g/dL (SD 1.03 g/dL based on an analysis of patient characteristics in IDA trials. Costs were modeled using UK health care resource groups. Results: Using IIM required 1.3 infusions to correct the mean iron deficit, compared with 1.3, 1.8, and 7.7 with LMWID, FCM, and IS, respectively. Patients using IIM required multiple infusions in 35% of cases, compared with 35%, 77%, and 100% of patients with LMWID, FCM, and IS, respectively. Total costs were estimated to be GBP 451 per patient with IIM or LMWID, relative to GBP 594 with FCM (a GBP 143 or 24% saving with IIM or GBP 2,600 with IS (a GBP 2,149 or 83% saving with IIM. Conclusion: Using IIM or LMWID in place of FCM or IS resulted in a marked reduction in the number of infusions required to correct iron deficits in patients with IDA. The reduction in infusions was accompanied by substantial reductions in cost relative to FCM and IS over 1 year. Keywords: iron

  2. Development of the Facility for Transformation of Magnetic Characteristics of Weakly Magnetic Oxidized Iron Ores Related to Improvement of Technologies for Iron Ore Concentrate Production

    Directory of Open Access Journals (Sweden)

    Ponomarenko, O.M.

    2016-01-01

    Full Text Available New facility for continuous registration of iron ore magnetization depending on temperature by heating of iron ores upon reducing conditions was created. Facility allows to register the processes of transformation of weakly magnetic minerals into strongly magnetic ones under the influence of reducing agents and temperature, as well as to determine the Curie temperature of the minerals. Using created facility it was shown, that heating of goethite and hematite in the presence of 4 % of starch in the temperature range of 300—650 °С leads to significant increase of magnetization of the samples. X-Ray diffraction confirmed that under indicated conditions the structure of hematite and goethite is transformed into magnetite structure. Obtained results open up new possibilities for the development of effective technologies for oxidized iron ore beneficiation.

  3. Serious fighting-related injuries produce a significant reduction in intelligence.

    Science.gov (United States)

    Schwartz, Joseph A; Beaver, Kevin M

    2013-10-01

    Fighting-related injuries are common among adolescents within the United States, but how such injuries relate to subsequent cognitive functioning remains unclear. In particular, the long-term effect of fighting-related injuries suffered during important developmental periods, such as adolescence, on subsequent cognitive functioning has been overlooked by previous studies. The purpose of this study is to examine the association between sustaining serious fighting-related injuries and changes in verbal intelligence (IQ) over a 5- to 6-year time period. Longitudinal multivariate statistical models were used to analyze data from the National Longitudinal Study of Adolescent Health collected between 1994 and 2002 and analyzed in 2013. Even a single fighting-related injury resulted in a significant reduction in IQ over time even after controlling for age, race, sex, and changes in socioeconomic status (SES) over the study period. Additionally, females experienced a significantly greater reduction in IQ from each fighting-related injury than males. Fighting-related injuries have a significant impact on subsequent cognitive functioning and intelligence. The implications for future policies and research are discussed in more detail. Copyright © 2013 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  4. Relating Magnetic Properties and High Hyperthermia Performance of Iron Oxide Nanoflowers

    DEFF Research Database (Denmark)

    Bender, Philipp; Fock, Jeppe; Frandsen, Cathrine

    2018-01-01

    We investigated in depth the interrelations among structure, magnetic properties, relaxation dynamics and magnetic hyperthermia performance of magnetic nanoflowers. The nanoflowers are about 39 nm in size, and consist of densely packed iron oxide cores. They display a remanent magnetization, which...... we explain by the exchange coupling between the cores, but we observe indications for internal spin disorder. By polarized small angle neutron scattering we unambiguously confirm that on average the nanoflowers are preferentially magnetized along one direction. The extracted discrete relaxation time...... distribution of the colloidally dispersed particles indicates the presence of three distinct relaxation contributions. We can explain the two slower processes by Brownian and classical Néel relaxation, respectively. The additionally observed very fast relaxation contributions are attributed by us...

  5. Iron plaque formation on roots of different rice cultivars and the relation with lead uptake.

    Science.gov (United States)

    Liu, Jianguo; Leng, Xuemei; Wang, Mingxin; Zhu, Zhongquan; Dai, Qinghua

    2011-07-01

    The relationships between lead (Pb) uptake and iron/manganese plaque formation on rice roots were investigated with three cultivars. The results showed that the rice cultivars with indica consanguinity were more sensitive to soil Pb stress than the cultivar with japonica consanguinity. Pb concentrations and distribution ratios in root tissues were in the order: Shanyou 63 > Yangdao 6 > Wuyunjing 7, but Pb and Fe concentrations and distribution ratios in the plaques showed a reverse order. Mn concentrations and distribution ratios in the plaques of Wuyunjing 7 were significantly higher (P rice root can provide a barrier to soil Pb stress. The plaque will increase sequestration of Pb on rice root surface and in the rhizosphere, providing a means of external exclusion of soil Pb to some extent. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Determination of plutonium in nitric acid solutions - Method by oxidation by cerium(IV), reduction by iron(II) ammonium sulfate and amperometric back-titration with potassium dichromate

    International Nuclear Information System (INIS)

    1987-01-01

    This International Standard specifies a precise and accurate analytical method for determining plutonium in nitric acid solutions. Plutonium is oxidized to plutonium(VI) in a 1 mol/l nitric acid solution with cerium(IV). Addition of sulfamic acid prevents nitrite-induced side reactions. The excess of cerium(IV) is reduced by adding a sodium arsenite solution, catalysed by osmium tetroxide. A slight excess of arsenite is oxidized by adding a 0.2 mol/l potassium permanganate solution. The excess of permanganate is reduced by adding a 0.1 mol/l oxalic acid solution. Iron(III) is used to catalyse the reduction. A small excess of oxalic acid does not interfere in the subsequent plutonium determination. These reduction and oxidation stages can be followed amperometrically and the plutonium is left in the hexavalent state. The sulfuric acid followed by a measured amount of standardized iron(II) ammonium sulfate solution in excess of that required to reduce the plutonium(VI) to plutonium(IV) is added. The excess iron(II) and any plutonium(III) formed to produce iron(III) and plutonium(IV) is amperometrically back-titrated using a standard potassium dichromate solution. The method is almost specifically for plutonium. It is suitable for the direct determination of plutonium in materials ranging from pure product solutions, to fast reactor fuel solutions with a uranium/plutonium ratio of up to 10:1, either before or after irradiation

  7. A coarse grained description of time evolution: Irreversible state reduction and time-energy relation

    International Nuclear Information System (INIS)

    Bonifacio, R.; Milan Univ.

    1983-05-01

    We show that a proper coarse-grained description of time evolution leads to a finite difference equation with step tau for the density operator. This implies state reduction to the diagonal form in the energy representation and a quasi ergodic behaviour of quantum mechanical ensemble averages. An intrinsic time-energy relation tauΔE>=(h/2π)/2 is proposed, and its equivalence to a time quantization is discussed. (author)

  8. A Moessbauer spectroscopic study of corrosion related reactions in the iron-hydrogen fluoride-water-oxygen system

    International Nuclear Information System (INIS)

    Crouse, P.L.

    1989-03-01

    The results of a study of a number of corrosion related reactions in the Fe-HF-H 2 O-O2 system are presented. The primary techniques used were transmission and conversion electron Moessbauer spectroscopy. Conversion electron Moessbauer spectra were recorded at very low γ-photon glancing angles and at normal incidence. Depth profiles of surface layers were obtained by recording spectra at different glancing angles. The initial product which forms when an iron surface is exposed to the vapour of azeotropic hydrofluoric acid was identified as FeF 25 ·47H 2 O. With increasing film thickness, a product, identified as non-stoichiometric Fe 2 F 5 ·7H 2 O, was shown to occur. A thermodynamic analysis of the system is presented which shows FeF 3 ·3H 2 O to be the most stable compound under the experimental conditions used, and suggests a stepwise reaction sequence in which FeF 2 ·4H 2 O forms first, followed by Fe 2 F 5 ·7H 2 O and finally FeF 3 ·3H 2 O. Results obtained in a gravimetric study reveal the rate of reaction of metallic iron with the azeotropic vapour to be controlled by the rate of diffusion of the gaseous species through the product layer. In the case of the reactions with the vapour of higher dilutions of aqueous HF, the chemical reaction between the iron substrate and the gaseous species is rate controlling. 86 refs., 61 figs., 14 tabs

  9. The effect of structurally related impurities on crystallinity reduction of sulfamethazine by grinding.

    Science.gov (United States)

    Hamada, Yoshito; Ono, Makoto; Ohara, Motomu; Yonemochi, Etsuo

    2016-12-30

    In this study, the effect of structurally related impurities on crystallinity reduction of sulfamethazine by grinding was evaluated. The crystallinity of sulfamethazine was not decreased when it was ground alone. However, when structurally related impurities with sulfonamide derivatives were blended, the crystallinity of sulfamethazine was decreased by grinding. Other materials without a sulfonamide moiety showed no such effect. The Raman spectra of sulfamethazine demonstrated that there was a difference between its crystalline and amorphous states within its sulfonamide structure. It was suggested that the sulfonamide structure of the impurities was important in causing the inhibition of recrystallization of sulfamethazine during grinding. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Efficient solar-assisted O2 reduction by a cofacial iron porphyrin dimer integrated to a p-CuBi2O4 photocathode prepared by a simple novel method.

    Science.gov (United States)

    Zahran, Zaki N; Mohamed, Eman A; Naruta, Yoshinori; Haleem, Ashraf

    2017-10-04

    A cofacial iron porphyrin hetero-dimer, Fe2TPFPP-TMP showed high electro-catalytic activity, selectivity, and stability for the O2 reduction to H2O both in homogeneous non-aqueous and heterogeneous neutral aqueous solutions. Moreover, when it is integrated to FTO/p-CuBi2O4 (FTO = fluorine doped tin oxide) photocathode prepared by a simple novel method, a remarkable efficient solar-assisted O2 reduction is achieved in neutral potassium phosphate (KPi) or basic NaOH solutions saturated with O2. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Iron metal production in silicate melts through the direct reduction of Fe/II/ by Ti/III/, Cr/II/, and Eu/II/. [in lunar basalts

    Science.gov (United States)

    Schreiber, H. D.; Balazs, G. B.; Shaffer, A. P.; Jamison, P. L.

    1982-01-01

    The production of metallic iron in silicate melts by chemical reactions of Ti(3+), Cr(2+), and Eu(2+) with Fe(2+) is demonstrated under experimental conditions in a simplified basaltic liquid. These reactions form a basis for interpreting the role of isochemical valency exchange models in explanations for the reduced nature of lunar basalts. The redox couples are individually investigated in the silicate melt to ascertain reference redox ratios that are independent of mutual interactions. These studies also provide calibrations of spectral absorptions of the Fe(2+) and Ti(2+) species in these glasses. Subsequent spectrophotometric analyses of Fe(2+) and Ti(2+) in glasses doped with both iron and titanium and of Fe(2+) in glasses doped with either iron and chromium or iron and europium ascertain the degree of mutual interactions in these dual-doped glasses.

  12. Reducing catheter-related thrombosis using a risk reduction tool centered on catheter to vessel ratio.

    Science.gov (United States)

    Spencer, Timothy R; Mahoney, Keegan J

    2017-11-01

    In vascular access practices, the internal vessel size is considered important, and a catheter to vessel ratio (CVR) is recommended to assist clinicians in selecting the most appropriate-sized device for the vessel. In 2016, new practice recommendations stated that the CVR can increase from 33 to 45% of the vessels diameter. There has been evidence on larger diameter catheters and increased thrombosis risk in recent literature, while insufficient information established on what relationship to vessel size is appropriate for any intra-vascular device. Earlier references to clinical standards and guidelines did not clearly address vessel size in relation to the area consumed or external catheter diameter. The aim of this manuscript is to present catheter-related thrombosis evidence and develop a standardized process of ultrasound-guided vessel assessment, integrating CVR, Virchow's triad phenomenon and vessel health and preservation strategies, empowering an evidence-based approach to device placement. Through review, calculation and assessment on the areas of the 33 and 45% rule, a preliminary clinical tool was developed to assist clinicians make cognizant decisions when placing intravascular devices relating to target vessel size, focusing on potential reduction in catheter-related thrombosis. Increasing the understanding and utilization of CVRs will lead to a safer, more consistent approach to device placement, with potential thrombosis reduction strategies. The future of evidence-based data relies on the clinician to capture accurate vessel measurements and device-related outcomes. This will lead to a more dependable data pool, driving the relationship of catheter-related thrombosis and vascular assessment.

  13. Analysis of iron acquisition and storage-related genes in clinical and non-clinical strains of Yersinia enterocolitica biovar 1A.

    Science.gov (United States)

    Kanaujia, Pawan Kumar; Bajaj, Priyanka; Virdi, Jugsharan Singh

    2015-10-01

    Possession of mechanisms for iron acquisition and its storage enhances the ability of the bacteria to survive in the iron-limiting environment of the host. In this study, 81 strains of Yersinia enterocolitica biovar 1A isolated from various clinical (n = 51) and non-clinical (n = 30) sources were investigated for the presence of the genes related to iron acquisition and storage. Important genes which were present in more than 85% of the strains included hasA, foxA, bfr, bfd, ftnA, and hmsT as well as the fhuCDB, fepBDGCfesfepA, feoAB, yfuABCD, hemPRSTUV, and hmsHFRS gene clusters. Majority of these genes is being reported for the first time in biovar 1A strains and showed significant homology with genes present in the known pathogenic biovars of Y. enterocolitica. However, no significant difference was observed in the distribution of iron acquisition and storage-related genes among clinical and non-clinical biovar 1A strains. Thus, it may be suggested that the presence of iron acquisition and storage-related genes per se might not be responsible for the supposedly better ability of clinical biovar 1A strains to cause infections in humans. However, in the backdrop of this data, the need to undertake functional studies are highly recommended. © 2015 APMIS. Published by John Wiley & Sons Ltd.

  14. Antioxidant capacity of parsley cells (Petroselinum crispum L.) in relation to iron-induced ferritin levels and static magnetic field.

    Science.gov (United States)

    Rajabbeigi, Elham; Ghanati, Faezeh; Abdolmaleki, Parviz; Payez, Atefeh

    2013-12-01

    This study was aimed to evaluate antioxidant response of parsley cells to 21 ppm iron and static magnetic field (SMF; 30 mT). The activity of catalase (CAT) and ascorbate peroxidase (APX) and the contents of malonyldialdehyde, iron and ferritin were measured at 6 and 12 h after treatments. Exposure to SMF increased the activity of CAT in treated cells, while combination of iron and SMF treatments as well as iron supply alone decreased CAT activity, compared to that of control cells. Combination of SMF with iron treatment reduced iron content of the cells and ameliorated mal effect of iron on CAT activity. All treatments reduced APX activity; however, the content of total ascorbate increased in response to iron and SMF+iron. The results showed that among the components of antioxidant system of parsley cells, enhanced activity of CAT in SMF-treated cells and increase of ascorbate in SMF+Fe-treated ones were responsible for the maintenance of membranes integrity. Ferritin contents of SMF- and SMF+Fe-treated cells also decreased significantly 12 h after treatments, compared to those of the control cells. These results cast doubt on the proposed functions of ferritin as a putative reactive oxygen species detoxifying molecule.

  15. Inventories and reduction scenarios of urban waste-related greenhouse gas emissions for management potential.

    Science.gov (United States)

    Yang, Dewei; Xu, Lingxing; Gao, Xueli; Guo, Qinghai; Huang, Ning

    2018-06-01

    Waste-related greenhouse gas (GHG) emissions have been recognized as one of the prominent contributors to global warming. Current urban waste regulations, however, face increasing challenges from stakeholders' trade-offs and hierarchic management. A combined method, i.e., life cycle inventories and scenario analysis, was employed to investigate waste-related GHG emissions during 1995-2015 and to project future scenarios of waste-driven carbon emissions by 2050 in a pilot low carbon city, Xiamen, China. The process-based carbon analysis of waste generation (prevention and separation), transportation (collection and transfer) and disposal (treatment and recycling) shows that the main contributors of carbon emissions are associated with waste disposal processes, solid waste, the municipal sector and Xiamen Mainland. Significant spatial differences of waste-related CO 2e emissions were observed between Xiamen Island and Xiamen Mainland using the carbon intensity and density indexes. An uptrend of waste-related CO 2e emissions from 2015 to 2050 is identified in the business as usual, waste disposal optimization, waste reduction and the integrated scenario, with mean annual growth rates of 8.86%, 8.42%, 6.90% and 6.61%, respectively. The scenario and sensitivity analysis imply that effective waste-related carbon reduction requires trade-offs among alternative strategies, actions and stakeholders in a feasible plan, and emphasize a priority of waste prevention and collection in Xiamen. Our results could benefit to the future modeling of urban multiple wastes and life-cycle carbon control in similar cities within and beyond China. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Age-related reduction of hemispheric lateralisation for spatial attention: An EEG study.

    Science.gov (United States)

    Learmonth, Gemma; Benwell, Christopher S Y; Thut, Gregor; Harvey, Monika

    2017-06-01

    A group-level visuospatial attention bias towards the left side of space (pseudoneglect) is consistently observed in young adults, which is likely to be a consequence of right parieto-occipital dominance for spatial attention. Conversely, healthy older adults demonstrate a rightward shift of this behavioural bias, hinting that an age-related reduction of lateralised neural activity may occur within visuospatial attention networks. We compared young (aged 18-25) and older (aged 60-80) adults on a computerised line bisection (landmark) task whilst recording event-related potentials (ERPs). Full-scalp cluster mass permutation tests identified a larger right parieto-occipital response for long lines compared to short in young adults (confirming Benwell et al., 2014a) which was not present in the older group. To specifically investigate age-related differences in hemispheric lateralisation, cluster mass permutation tests were then performed on a lateralised EEG dataset (RH-LH electrodes). A period of right lateralisation was identified in response to long lines in young adults, which was not present for short lines. No lateralised clusters were present for either long or short lines in older adults. Additionally, a reduced P300 component amplitude was observed for older adults relative to young. We therefore report here, for the first time, an age-related and stimulus-driven reduction of right hemispheric control of spatial attention in older adults. Future studies will need to determine whether this is representative of the normal aging process or an early indicator of neurodegeneration. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  17. Cast iron - a predictable material

    Directory of Open Access Journals (Sweden)

    Jorg C. Sturm

    2011-02-01

    Full Text Available High strength compacted graphite iron (CGI or alloyed cast iron components are substituting previously used non-ferrous castings in automotive power train applications. The mechanical engineering industry has recognized the value in substituting forged or welded structures with stiff and light-weight cast iron castings. New products such as wind turbines have opened new markets for an entire suite of highly reliable ductile iron cast components. During the last 20 years, casting process simulation has developed from predicting hot spots and solidification to an integral assessment tool for foundries for the entire manufacturing route of castings. The support of the feeding related layout of the casting is still one of the most important duties for casting process simulation. Depending on the alloy poured, different feeding behaviors and self-feeding capabilities need to be considered to provide a defect free casting. Therefore, it is not enough to base the prediction of shrinkage defects solely on hot spots derived from temperature fields. To be able to quantitatively predict these defects, solidification simulation had to be combined with density and mass transport calculations, in order to evaluate the impact of the solidification morphology on the feeding behavior as well as to consider alloy dependent feeding ranges. For cast iron foundries, the use of casting process simulation has become an important instrument to predict the robustness and reliability of their processes, especially since the influence of alloying elements, melting practice and metallurgy need to be considered to quantify the special shrinkage and solidification behavior of cast iron. This allows the prediction of local structures, phases and ultimately the local mechanical properties of cast irons, to asses casting quality in the foundry but also to make use of this quantitative information during design of the casting. Casting quality issues related to thermally driven

  18. Geochemistry and microbiology of iron-related well-screen encrustation and aquifer biofouling in Suffolk County, Long Island, New York

    Science.gov (United States)

    Walter, D.A.

    1997-01-01

    Iron-related well-screen encrustation and aquifer biofouling has decreased the specific capacity of several production wells in Suffolk County, N.Y., and has forced the Suffolk County Water Authority to adopt a costly well-reconditioning and replacement program. The specific-capacity declines are the result of the precipitation of iron oxyhydroxides and the growth of iron bacteria on the well screens and in the pore spaces of the surrounding formation. Mineralogic and chemical analyses indicate that the inorganic part of the encrusting material consists primarily of amorphous ferric hydroxide (Fe(OH)3 ); minor components of the material include goethite (FeOOH), hematite (Fe2 O 3 ), and quartz (SiO 2 ). The weight percent of ferric hydroxide in the material ranged from 32.3 to 98.6 percent and averaged 64.3 percent. Equilibrium modeling indicated that during pumping the well waters were supersaturated with respect to goethite, hematite, magnetite, and quartz and were under-saturated with respect to ferric hydroxide. Theoretical Eh values computed for the ferrous/ferric-iron redox couple and the oxygen/water redox couple averaged 390 millivolts and 810 millivolts, respectively, indicating that the waters were in a state of redox disequilibrium. The disequilibrium condition arises from the mixing of ground water with a low dissolved-oxygen concentration with oxygenated ground water during operation of the well. The low pH of the ground water contributes to the disequilibrium condition by slowing the rate of iron oxidation after the introduction of oxygen. Chemical and mineralogical data indicate that most of the encrusting material in the wells was deposited while the wells were shut down, probably in response to the use of treated water of higher pH to keep pump turbines wet while the wells were not in operation; the increased pH of water in the static water column increases the rate of ferrous-iron oxidation and causes the well water to become increasingly

  19. Effect of short-term food restriction on iron metabolism, relative well-being and depression symptoms in healthy women.

    Science.gov (United States)

    Wojciak, Rafal W

    2014-01-01

    The idea that iron deficiency anemia can be recognized in depressive patients has been around for a few years, as well as negative association between ferritin levels and depression. Iron deficiency anemia, associated with low iron intake, has been observed in women using restriction diets, for example in vegetarians or anorexics. There are no data on the influence of the short-term food restrictions, observed for example in slimming women, on iron management and its connection with behavior expressed via changes in the subject's emotional state. This study describes the effect of one- and two-day food restrictions (every 8 days for a period of 48 days) on selected iron management parameters in the serum and blood of 46 healthy volunteer women (23 in each group), aged 25.5 ± 3.0 years, in association with the subjects' self-described emotional status and depression symptoms. The association between iron parameters and depression was also analyzed. Results show that short-term (2 days) fasting significantly decreases iron concentrations in serum and hair, as well as levels of ferritin, hemoglobin, hematocrit, red blood cells, and total iron binding capacity, but the short-term fasting did not influence the other iron management parameters. Each model of food restrictions also increased negative feelings towards depression. A significant negative correlation between serum ferritin levels and depression was found in women who starved for 2 days. The study shows that, through an impact on mineral levels, even short-term food restrictions, as observed in many slimming women and girls, can be a reason for iron deficiency and also can alter the emotional status of healthy women. Maybe depression symptoms in anorexia or other eating disorders patients can be associated with iron deficiencies.

  20. On the dynamics of the preference-performance relation for hearing aid noise reduction

    DEFF Research Database (Denmark)

    Fischer, Rosa-Linde; Wagener, Kirsten C.; Vormann, Matthias

    on the data collected during the first laboratory assessment of the study. In particular, the influence of hearing aid experience and individual noise sensitivity on the preference-performance relation will be presented and discussed. REFERENCES S. Getzmann, E. Wascher and M. Falkenstein (2015). "What does......Previous research has shown that hearing aid users can differ substantially in their preference for noise reduction (NR) strength, and that preference for and speech recognition with NR processing typically are not correlated (e.g. Neher 2014; Serman et al. 2016). In other words, hearing aid users...... may prefer a certain NR setting, but perform better with a different one. The aim of the present work was to investigate the influence of individual noise sensitivity, hearing aid experience and acclimatization on the preference-performance relation for different NR settings. For this purpose...

  1. Electrochemistry of Simple Organometallic Models of Iron-Iron Hydrogenases in Organic Solvent and Water.

    Science.gov (United States)

    Gloaguen, Frederic

    2016-01-19

    Synthetic models of the active site of iron-iron hydrogenases are currently the subjects of numerous studies aimed at developing H2-production catalysts based on cheap and abundant materials. In this context, the present report offers an electrochemist's view of the catalysis of proton reduction by simple binuclear iron(I) thiolate complexes. Although these complexes probably do not follow a biocatalytic pathway, we analyze and discuss the interplay between the reduction potential and basicity and how these antagonist properties impact the mechanisms of proton-coupled electron transfer to the metal centers. This question is central to any consideration of the activity at the molecular level of hydrogenases and related enzymes. In a second part, special attention is paid to iron thiolate complexes holding rigid and unsaturated bridging ligands. The complexes that enjoy mild reduction potentials and stabilized reduced forms are promising iron-based catalysts for the photodriven evolution of H2 in organic solvents and, more importantly, in water.

  2. Arsenate and Arsenite Sorption on Magnetite: Relations to Groundwater Arsenic Treatment Using Zerovalent Iron and Natural Attenuation

    Science.gov (United States)

    Magnetite (Fe3O4) is a zerovalent iron corrosion product; it is also formed in natural soil and sediment. Sorption of arsenate (As(V)) and arsenite (As(III)) on magnetite is an important process of arsenic removal from groundwater using zerovalent iron-based permeable reactive ba...

  3. Geobacteraceae community composition is related to hydrochemistry and biodegradetion in an iron-reducing aquifer polluted by a neigbour landfill

    NARCIS (Netherlands)

    Lin, B; van Breukelen, B.M.; van Verseveld, H.W.; Westerhoff, H.V.; Roling, W.F.M.

    2005-01-01

    Relationships between community composition of the iron-reducing Geobacteraceae, pollution levels, and the occurrence of biodegradation were established for an iron-reducing aquifer polluted with landfill leachate by using cultivation-independent Geobacteraceae 16S rRNA gene-targeting techniques.

  4. Geobacteraceae community composition is related to hydrochemistry and biodegradation in an iron-reducing aquifer polluted by a neighboring landfill.

    NARCIS (Netherlands)

    Lin, B.; Braster, M.; van Breukelen, B.M.; van Verseveld, H.W.; Westerhoff, H.V.; Roling, W.F.M.

    2005-01-01

    Relationships between community composition of the iron-reducing Geobacteraceae, pollution levels, and the occurrence of biodegradation were established for an iron-reducing aquifer polluted with landfill leachate by using cultivation-independent Geobacteraceae 16S rRNA gene-targeting techniques.

  5. A deposit model for magmatic iron-titanium-oxide deposits related to Proterozoic massif anorthosite plutonic suites

    Science.gov (United States)

    Woodruff, Laurel G.; Nicholson, Suzanne W.; Fey, David L.

    2013-01-01

    This descriptive model for magmatic iron-titanium-oxide (Fe-Ti-oxide) deposits hosted by Proterozoic age massif-type anorthosite and related rock types presents their geological, mineralogical, geochemical, and geoenvironmental attributes. Although these Proterozoic rocks are found worldwide, the majority of known deposits are found within exposed rocks of the Grenville Province, stretching from southwestern United States through eastern Canada; its extension into Norway is termed the Rogaland Anorthosite Province. This type of Fe-Ti-oxide deposit dominated by ilmenite rarely contains more than 300 million tons of ore, with between 10- to 45-percent titanium dioxide (TiO2), 32- to 45-percent iron oxide (FeO), and less than 0.2-percent vanadium (V). The origin of these typically discordant ore deposits remains as enigmatic as the magmatic evolution of their host rocks. The deposits clearly have a magmatic origin, hosted by an age-constrained unique suite of rocks that likely are the consequence of a particular combination of tectonic circumstances, rather than any a priori temporal control. Principal ore minerals are ilmenite and hemo-ilmenite (ilmenite with extensive hematite exsolution lamellae); occurrences of titanomagnetite, magnetite, and apatite that are related to this deposit type are currently of less economic importance. Ore-mineral paragenesis is somewhat obscured by complicated solid solution and oxidation behavior within the Fe-Ti-oxide system. Anorthosite suites hosting these deposits require an extensive history of voluminous plagioclase crystallization to develop plagioclase-melt diapirs with entrained Fe-Ti-rich melt rising from the base of the lithosphere to mid- and upper-crustal levels. Timing and style of oxide mineralization are related to magmatic and dynamic evolution of these diapiric systems and to development and movement of oxide cumulates and related melts. Active mines have developed large open pits with extensive waste-rock piles, but

  6. The Reduction of Chazy Classes and Other Third-Order Differential Equations Related to Boundary Layer Flow Models

    International Nuclear Information System (INIS)

    Fakhar, K.; Kara, A. H.

    2012-01-01

    We study the symmetries, conservation laws and reduction of third-order equations that evolve from a prior reduction of models that arise in fluid phenomena. These could be the ordinary differential equations (ODEs) that are reductions of partial differential equations (PDEs) or, alternatively, PDEs related to given ODEs. In this class, the analysis includes the well-known Blasius, Chazy, and other associated third-order ODEs. (general)

  7. Time-Frequency Data Reduction for Event Related Potentials: Combining Principal Component Analysis and Matching Pursuit

    Directory of Open Access Journals (Sweden)

    Selin Aviyente

    2010-01-01

    Full Text Available Joint time-frequency representations offer a rich representation of event related potentials (ERPs that cannot be obtained through individual time or frequency domain analysis. This representation, however, comes at the expense of increased data volume and the difficulty of interpreting the resulting representations. Therefore, methods that can reduce the large amount of time-frequency data to experimentally relevant components are essential. In this paper, we present a method that reduces the large volume of ERP time-frequency data into a few significant time-frequency parameters. The proposed method is based on applying the widely used matching pursuit (MP approach, with a Gabor dictionary, to principal components extracted from the time-frequency domain. The proposed PCA-Gabor decomposition is compared with other time-frequency data reduction methods such as the time-frequency PCA approach alone and standard matching pursuit methods using a Gabor dictionary for both simulated and biological data. The results show that the proposed PCA-Gabor approach performs better than either the PCA alone or the standard MP data reduction methods, by using the smallest amount of ERP data variance to produce the strongest statistical separation between experimental conditions.

  8. Relative iron "overload" in offspring of patients with type 2 diabetes mellitus: a new component in the conundrum of insulin resistance syndrome?

    Science.gov (United States)

    Psyrogiannis, Agathoklis; Kyriazopoulou, Venetsana; Symeonidis, Argiris; Leotsinidis, Michalis; Vagenakis, Apostolos G

    2003-01-01

    There are a few reports suggesting that subtle disturbances of iron metabolism are frequently found in patients with type 2 diabetes (DM2), but it is not known if these disturbances precede or accompany the diabetic state. We investigated the serum iron indices in 41 offspring of DM2 parents (group I) with normal glucose tolerance, and in 49 offspring whose parents had no history of DM2 and were matched for sex, age, body mass index (BMI), waist to hip ratio (WHR) and blood pressure (group II). Serum iron, ferritin, total iron binding capacity (TIBC), transferrin saturation, serum triglycerides, cholesterol, Apo-B, high density lipoprotein (HDL) and glucose and insulin values during an oral glucose tolerance test were measured. Insulin resistance was assessed using the homeostasis model assessment (HOMA - Insuline resistence index-IRI). In comparison to controls (group II), the offspring of DM2 subjects (group I) had higher fasting serum triglycerides (mean +/- SD 2.25+/-2.08 vs. 1.6+/-0.8 mmol/L, pinsulin in the Area Under the Curve (204.7+/-140.8 v. 153.1 +/- 63.0 microU/ml, pinsulin resistance. Hence, the relative iron "overload" in offspring of type 2 diabetics is present along with insulin resistance and might worsen the hepatic insulin insensitivity already present in these patients.

  9. In vitro solubility of calcium, iron and zinc in relation to phytic acid levels in rice-based consumer products in China

    NARCIS (Netherlands)

    Liang, J.; Han, B.Z.; Nout, M.J.R.; Hamer, R.J.

    2010-01-01

    In vitro solubility of calcium, iron and zinc in relation to phytic acid (PA) levels in 30 commercial rice-based foods from China was studied. Solubility of minerals and molar ratios of PA to minerals varied with degrees of processing. In primary products, [PA]/[Ca] values were less than 5 and

  10. Intestinal Iron Homeostasis and Colon Tumorigenesis

    Directory of Open Access Journals (Sweden)

    Yatrik M. Shah

    2013-06-01

    Full Text Available Colorectal cancer (CRC is the third most common cause of cancer-related deaths in industrialized countries. Understanding the mechanisms of growth and progression of CRC is essential to improve treatment. Iron is an essential nutrient for cell growth. Iron overload caused by hereditary mutations or excess dietary iron uptake has been identified as a risk factor for CRC. Intestinal iron is tightly controlled by iron transporters that are responsible for iron uptake, distribution, and export. Dysregulation of intestinal iron transporters are observed in CRC and lead to iron accumulation in tumors. Intratumoral iron results in oxidative stress, lipid peroxidation, protein modification and DNA damage with consequent promotion of oncogene activation. In addition, excess iron in intestinal tumors may lead to increase in tumor-elicited inflammation and tumor growth. Limiting intratumoral iron through specifically chelating excess intestinal iron or modulating activities of iron transporter may be an attractive therapeutic target for CRC.

  11. Anaerobic transformation of DDT related to iron(III) reduction and microbial community structure in paddy soils.

    Science.gov (United States)

    Chen, Manjia; Cao, Fang; Li, Fangbai; Liu, Chengshuai; Tong, Hui; Wu, Weijian; Hu, Min

    2013-03-06

    We studied the mechanisms of microbial transformation in functional bacteria on 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) in two different field soils, Haiyan (HY) and Chenghai (CH). The results showed that microbial activities had a steady dechlorination effect on DDT and its metabolites (DDx). Adding lactate or glucose as carbon sources increased the amount of Desulfuromonas, Sedimentibacter, and Clostridium bacteria, which led to an increase in adsorbed Fe(II) and resulted in increased DDT transformation rates. The electron shuttle of anthraquinone-2,6-disulfonic disodium salt resulted in an increase in the negative potential of soil by mediating the electron transfer from the bacteria to the DDT. Moreover, the DDT-degrading bacteria in the CH soil were more abundant than those in the HY soil, which led to higher DDT transformation rates in the CH soil. The most stable compound of DDx was 1,1-dichloro-2,2-bis(p-chloro-phenyl)ethane, which also was the major dechlorination metabolite of DDT, and 1-chloro-2,2-bis-(p-chlorophenyl)ethane and 4,4'-dichlorobenzo-phenone were found to be the terminal metabolites in the anaerobic soils.

  12. Ironic processes in the mental control of mood and mood-related thought.

    Science.gov (United States)

    Wegner, D M; Erber, R; Zanakos, S

    1993-12-01

    The mental control of mood and mood-related thought was investigated. In Experiment 1, Ss reminiscing about a happy or sad event were asked to make their mood positive, were given no instructions, or were asked to make their mood negative. Ss attempting mood control without an imposed cognitive load were successful, whereas those who attempted control while rehearsing a 9-digit number not only failed to control their moods but also showed self-reported mood change opposite the mood they intended to create. In Experiment 2, Ss attempting to control mood-related thoughts under cognitive load showed increased accessibility of those thoughts contrary to the direction of intended control in a Stroop-type color-naming task.

  13. Reduction in Diarrhea- and Rotavirus-related Healthcare Visits Among Children Introduction in Zimbabwe.

    Science.gov (United States)

    Mujuru, Hilda A; Yen, Catherine; Nathoo, Kusum J; Gonah, Nhamo A; Ticklay, Ismail; Mukaratirwa, Arnold; Berejena, Chipo; Tapfumanei, Ottias; Chindedza, Kenneth; Rupfutse, Maxwell; Weldegebriel, Goitom; Mwenda, Jason M; Burnett, Eleanor; Tate, Jacqueline E; Parashar, Umesh D; Manangazira, Portia

    2017-10-01

    In Zimbabwe, rotavirus accounted for 41%-56% of acute diarrhea hospitalizations before rotavirus vaccine introduction in 2014. We evaluated rotavirus vaccination impact on acute diarrhea- and rotavirus-related healthcare visits in children. We examined monthly and annual acute diarrhea and rotavirus test-positive hospitalizations and Accident and Emergency Department visits among children introduction (2012-2013) with postvaccine introduction (2015 and 2016) data for 2 of the hospitals. We examined monthly acute diarrhea hospitalizations by year and age group for 2013-2016 from surveillance hospital registers and monthly acute diarrhea outpatient visits reported to the Ministry of Health and Child Care during 2012-2016. Active surveillance data showed winter seasonal peaks in diarrhea- and rotavirus-related visits among children introduction; the percentage of rotavirus test-positive visits followed a similar seasonal pattern and decrease. Hospital register data showed similar pre-introduction seasonal variation and post-introduction declines in diarrhea hospitalizations among children 0-11 and 12-23 months of age. Monthly variation in outpatient diarrhea-related visits mirrored active surveillance data patterns. At 2 surveillance hospitals, the percentage of rotavirus-positive visits declined by 40% and 43% among children 0-11 months of age and by 21% and 33% among children 12-23 months of age in 2015 and 2016, respectively. Initial reductions in diarrheal illness among children introduction are encouraging. These early results provide evidence to support continued rotavirus vaccination and rotavirus surveillance in Zimbabwe.

  14. Inhibition of Nitrate Reduction by NaCl Adsorption on a Nano-Zero-Valent Iron Surface during a Concentrate Treatment for Water Reuse

    DEFF Research Database (Denmark)

    Hwang, Yuhoon; Kim, Dogun; Shin, Hang-Sik

    2015-01-01

    Nanoscale zero-valent iron (NZVI) has been considered as a possible material to treat water and wastewater. However, it is necessary to verify the effect of the matrix components in different types of target water. In this study, different effects depending on the sodium chloride (Na...

  15. Rock magnetic and geochemical evidence for authigenic magnetite formation via iron reduction in coal-bearing sediments offshore Shimokita Peninsula, Japan (IODP Site C0020)

    Science.gov (United States)

    Phillips, Stephen C.; Johnson, Joel E.; Clyde, William C.; Setera, Jacob B.; Maxbauer, Daniel P.; Severmann, Silke; Riedinger, Natascha

    2017-06-01

    Sediments recovered at Integrated Ocean Drilling Program (IODP) Site C0020, in a fore-arc basin offshore Shimokita Peninsula, Japan, include numerous coal beds (0.3-7 m thick) that are associated with a transition from a terrestrial to marine depositional environment. Within the primary coal-bearing unit (˜2 km depth below seafloor) there are sharp increases in magnetic susceptibility in close proximity to the coal beds, superimposed on a background of consistently low magnetic susceptibility throughout the remainder of the recovered stratigraphic sequence. We investigate the source of the magnetic susceptibility variability and characterize the dominant magnetic assemblage throughout the entire cored record, using isothermal remanent magnetization (IRM), thermal demagnetization, anhysteretic remanent magnetization (ARM), iron speciation, and iron isotopes. Magnetic mineral assemblages in all samples are dominated by very low-coercivity minerals with unblocking temperatures between 350 and 580°C that are interpreted to be magnetite. Samples with lower unblocking temperatures (300-400°C), higher ARM, higher-frequency dependence, and isotopically heavy δ56Fe across a range of lithologies in the coal-bearing unit (between 1925 and 1995 mbsf) indicate the presence of fine-grained authigenic magnetite. We suggest that iron-reducing bacteria facilitated the production of fine-grained magnetite within the coal-bearing unit during burial and interaction with pore waters. The coal/peat acted as a source of electron donors during burial, mediated by humic acids, to supply iron-reducing bacteria in the surrounding siliciclastic sediments. These results indicate that coal-bearing sediments may play an important role in iron cycling in subsiding peat environments and if buried deeply through time, within the subsequent deep biosphere.

  16. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... en español Iron-deficiency anemia is a common type of anemia that occurs if you do not ... iron-deficiency anemia and help rule out other types of anemia. Treatment will explain treatment-related complications ...

  17. Iron deficiency and cognitive functions

    Directory of Open Access Journals (Sweden)

    Jáuregui-Lobera I

    2014-11-01

    Full Text Available Ignacio Jáuregui-Lobera Department of Nutrition and Bromatology, Pablo de Olavide University, Seville, Spain Abstract: Micronutrient deficiencies, especially those related to iodine and iron, are linked to different cognitive impairments, as well as to potential long-term behavioral changes. Among the cognitive impairments caused by iron deficiency, those referring to attention span, intelligence, and sensory perception functions are mainly cited, as well as those associated with emotions and behavior, often directly related to the presence of iron deficiency anemia. In addition, iron deficiency without anemia may cause cognitive disturbances. At present, the prevalence of iron deficiency and iron deficiency anemia is 2%–6% among European children. Given the importance of iron deficiency relative to proper cognitive development and the alterations that can persist through adulthood as a result of this deficiency, the objective of this study was to review the current state of knowledge about this health problem. The relevance of iron deficiency and iron deficiency anemia, the distinction between the cognitive consequences of iron deficiency and those affecting specifically cognitive development, and the debate about the utility of iron supplements are the most relevant and controversial topics. Despite there being methodological differences among studies, there is some evidence that iron supplementation improves cognitive functions. Nevertheless, this must be confirmed by means of adequate follow-up studies among different groups. Keywords: iron deficiency, anemia, cognitive functions, supplementation

  18. Reactive oxygen species and associated reactivity of peroxymonosulfate activated by soluble iron species.

    Science.gov (United States)

    Watts, Richard J; Yu, Miao; Teel, Amy L

    2017-10-01

    The activation of peroxymonosulfate by iron (II), iron (III), and iron (III)-EDTA for in situ chemical oxidation (ISCO) was compared using nitrobenzene as a hydroxyl radical probe, anisole as a hydroxyl radical+sulfate radical probe, and hexachloroethane as a reductant+nucleophile probe. In addition, activated peroxymonosulfate was investigated for the treatment of the model groundwater contaminants perchloroethylene (PCE) and trichloroethylene (TCE). The relative activities of hydroxyl radical and sulfate radical in the degradation of the probe compounds and PCE and TCE were isolated using the radical scavengers tert-butanol and isopropanol. Iron (II), iron (III), and iron (III)-EDTA effectively activated peroxymonosulfate to generate hydroxyl radical and sulfate radical, but only a minimal flux of reductants or nucleophiles. Iron (III)-EDTA was a more effective activator than iron (II) and iron (III), and also provided a non-hydroxyl radical, non-sulfate radical degradation pathway. The contribution of sulfate radical relative to hydroxyl radical followed the order of anisole>TCE>PCE >nitrobenzene; i.e., sulfate radical was less dominant in the oxidation of more oxidized target compounds. Sulfate radical is often assumed to be the primary oxidant in activated peroxymonosulfate and persulfate systems, but the results of this research demonstrate that the reactivity of sulfate radical with the target compound must be considered before drawing such a conclusion. Published by Elsevier B.V.

  19. Reactive oxygen species and associated reactivity of peroxymonosulfate activated by soluble iron species

    Science.gov (United States)

    Watts, Richard J.; Yu, Miao; Teel, Amy L.

    2017-10-01

    The activation of peroxymonosulfate by iron (II), iron (III), and iron (III)-EDTA for in situ chemical oxidation (ISCO) was compared using nitrobenzene as a hydroxyl radical probe, anisole as a hydroxyl radical + sulfate radical probe, and hexachloroethane as a reductant + nucleophile probe. In addition, activated peroxymonosulfate was investigated for the treatment of the model groundwater contaminants perchloroethylene (PCE) and trichloroethylene (TCE). The relative activities of hydroxyl radical and sulfate radical in the degradation of the probe compounds and PCE and TCE were isolated using the radical scavengers tert-butanol and isopropanol. Iron (II), iron (III), and iron (III)-EDTA effectively activated peroxymonosulfate to generate hydroxyl radical and sulfate radical, but only a minimal flux of reductants or nucleophiles. Iron (III)-EDTA was a more effective activator than iron (II) and iron (III), and also provided a non-hydroxyl radical, non-sulfate radical degradation pathway. The contribution of sulfate radical relative to hydroxyl radical followed the order of anisole > > TCE > PCE > > nitrobenzene; i.e., sulfate radical was less dominant in the oxidation of more oxidized target compounds. Sulfate radical is often assumed to be the primary oxidant in activated peroxymonosulfate and persulfate systems, but the results of this research demonstrate that the reactivity of sulfate radical with the target compound must be considered before drawing such a conclusion.

  20. 49 CFR 192.369 - Service lines: Connections to cast iron or ductile iron mains.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Service lines: Connections to cast iron or ductile iron mains. 192.369 Section 192.369 Transportation Other Regulations Relating to Transportation... ductile iron mains. (a) Each service line connected to a cast iron or ductile iron main must be connected...

  1. Environmental selection pressures related to iron utilization are involved in the loss of the flavodoxin gene from the plant genome.

    Science.gov (United States)

    Pierella Karlusich, Juan J; Ceccoli, Romina D; Graña, Martín; Romero, Héctor; Carrillo, Néstor

    2015-02-16

    Oxidative stress and iron limitation represent the grim side of life in an oxygen-rich atmosphere. The versatile electron transfer shuttle ferredoxin, an iron-sulfur protein, is particularly sensitive to these hardships, and its downregulation under adverse conditions severely compromises survival of phototrophs. Replacement of ferredoxin by a stress-resistant isofunctional carrier, flavin-containing flavodoxin, is a widespread strategy employed by photosynthetic microorganisms to overcome environmental adversities. The flavodoxin gene was lost in the course of plant evolution, but its reintroduction in transgenic plants confers increased tolerance to environmental stress and iron starvation, raising the question as to why a genetic asset with obvious adaptive value was not kept by natural selection. Phylogenetic analyses reveal that the evolutionary history of flavodoxin is intricate, with several horizontal gene transfer events between distant organisms, including Eukarya, Bacteria, and Archaea. The flavodoxin gene is unevenly distributed in most algal lineages, with flavodoxin-containing species being overrepresented in iron-limited regions and scarce or absent in iron-rich environments. Evaluation of cyanobacterial genomic and metagenomic data yielded essentially the same results, indicating that there was little selection pressure to retain flavodoxin in iron-rich coastal/freshwater phototrophs. Our results show a highly dynamic evolution pattern of flavodoxin tightly connected to the bioavailability of iron. Evidence presented here also indicates that the high concentration of iron in coastal and freshwater habitats may have facilitated the loss of flavodoxin in the freshwater ancestor of modern plants during the transition of photosynthetic organisms from the open oceans to the firm land. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  2. Fuel saving, carbon dioxide emission avoidance, and syngas production by tri-reforming of flue gases from coal- and gas-fired power stations, and by the carbothermic reduction of iron oxide

    International Nuclear Information System (INIS)

    Halmann, M.; Steinfeld, A.

    2006-01-01

    Flue gases from coal, gas, or oil-fired power stations, as well as from several heavy industries, such as the production of iron, lime and cement, are major anthropogenic sources of global CO 2 emissions. The newly proposed process for syngas production based on the tri-reforming of such flue gases with natural gas could be an important route for CO 2 emission avoidance. In addition, by combining the carbothermic reduction of iron oxide with the partial oxidation of the carbon source, an overall thermoneutral process can be designed for the co-production of iron and syngas rich in CO. Water-gas shift (WGS) of CO to H 2 enables the production of useful syngas. The reaction process heat, or the conditions for thermoneutrality, are derived by thermochemical equilibrium calculations. The thermodynamic constraints are determined for the production of syngas suitable for methanol, hydrogen, or ammonia synthesis. The environmental and economic consequences are assessed for large-scale commercial production of these chemical commodities. Preliminary evaluations with natural gas, coke, or coal as carbon source indicate that such combined processes should be economically competitive, as well as promising significant fuel saving and CO 2 emission avoidance. The production of ammonia in the above processes seems particularly attractive, as it consumes the nitrogen in the flue gases

  3. Relation between hyperfine field and lattice location measurements for heavy impurities in iron: influence of radiation damage

    International Nuclear Information System (INIS)

    Thome, L.; Bernas, H.; Cohen, C.

    1978-01-01

    The relation between the hyperfine interaction (HFI) and the lattice location of heavy impurities in iron is discussed in the light of results (see companion papers) on 169 Yb, 175 Yb and Au in Fe. A compilation of all known results in Fe and Cu reveals a simple correlation between the difference in atomic radii of implanted and host atoms and the corrected extinction ratio in lattice location experiments. A simple model is developed to account simultaneously for the annealing -and implantation- temperature dependence of the impurity HFI and lattice location in Fe between room temperature and 800K. It is based on existing information concerning the nature and evolution of radiation damage in Fe: impurity evolution is described in terms of a two-stage process involving (i) vacancy migration towards the impurity and (ii) migration of the impurity-vacancy complex, with the latter stage being much faster than the former. Quantitative agreement is found with our experimental results, as well as with results obtained on other impurities in Fe. It is suggested that the model is applicable in all cases where vacancy motion determines impurity evolution

  4. Associations between Common Variants in Iron-Related Genes with Haematological Traits in Populations of African Ancestry.

    Science.gov (United States)

    Gichohi-Wainaina, Wanjiku N; Tanaka, Toshiko; Towers, G Wayne; Verhoef, Hans; Veenemans, Jacobien; Talsma, Elise F; Harryvan, Jan; Boekschoten, Mark V; Feskens, Edith J; Melse-Boonstra, Alida

    2016-01-01

    Large genome-wide association (GWA) studies of European ancestry individuals have identified multiple genetic variants influencing iron status. Studies on the generalizability of these associations to African ancestry populations have been limited. These studies are important given interethnic differences in iron status and the disproportionate burden of iron deficiency among African ancestry populations. We tested the associations of 20 previously identified iron status-associated single nucleotide polymorphisms (SNPs) in 628 Kenyans, 609 Tanzanians, 608 South Africans and 228 African Americans. In each study, we examined the associations present between 20 SNPs with ferritin and haemoglobin, adjusting for age, sex and CRP levels. In the meta analysis including all 4 African ancestry cohorts, we replicated previously reported associations with lowered haemoglobin concentrations for rs2413450 (β = -0.19, P = 0.02) and rs4820268 (β = -0.16, P = 0.04) in TMPRSS6. An association with increased ferritin concentrations was also confirmed for rs1867504 in TF (β = 1.04, P = ancestry individuals. While there is now evidence for the associations of a number of genetic variants with iron status in both European and African ancestry populations, the considerable lack of concordance highlights the importance of continued ancestry-specific studies to elucidate the genetic underpinnings of iron status in ethnically diverse populations.

  5. Prevalence of iron deficiency without anaemia in inflammatory bowel disease and impact on health-related quality of life.

    Science.gov (United States)

    González Alayón, Carlos; Pedrajas Crespo, Carolina; Marín Pedrosa, Sandra; Benítez, José Manuel; Iglesias Flores, Eva; Salgueiro Rodríguez, Isabel; Medina Medina, Rosario; García-Sánchez, Valle

    2018-01-01

    Iron deficiency without anaemia (IDWA) is commonly found in outpatients with inflammatory bowel disease (IBD) in an even higher proportion than anaemia. However, its true prevalence and possible impact on health-related quality of life (HRQoL) are unknown. The objectives of this study were: to establish the prevalence of IDWA, identify possible associated factors and measure their impact on HRQoL. 127 patients with IBD in an outpatient setting were consecutively included in an observational, descriptive, cross-sectional study. IDWA was defined as ferritin levels of <100 ng/ml with inflammatory activity or ≤30 ng/ml without it, with transferrin saturation of ≤16%, and with normal haemoglobin levels. HRQoL was assessed using two questionnaires: the IBDQ-9 for symptoms related to IBD and the FACIT-F to measure the presence of fatigue. Fatigue was considered extreme with a score of ≤30 points. The prevalence of IDWA was 37%. Variables associated with its occurrence were female gender (OR=2.9; p=.015) and the presence of inflammatory activity (OR=9.4; p=.001). Patients with IDWA presented HRQoL questionnaires with lower overall scores; decreases of 6.6 (p<.001) and 4.3 (p=.037) points in the IBDQ-9 and the FACIT-F were recorded, respectively. In addition, an increase of 29.4% in the presence of extreme fatigue was observed. The prevalence of IDWA is considerable in outpatients with IBD. IDWA is associated with female gender and inflammatory activity. It has a clear negative impact on HRQoL. A more active approach is needed to treat this complication. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

  6. Effect of fully and semi austempering treatment on the fatigue properties of ductile cast iron

    International Nuclear Information System (INIS)

    Kim, Min Gun; Lim, Bok Kyu; Hwang, Jung Gak; Kim, Dong Youl

    2005-01-01

    Single phase bainite structure which is obtained by the conventional austempering treatment reduces the ductility of ductile cast iron. Because of the reduction of ductility it is possible to worsen the fatigue properties. Therefore, semi austempered ductile iron which is treated from α+γ is prepared to investigate the static strength and fatigue properties in comparison with fully austempered ductile iron (is treated from γ). In spite of semi austempered ductile iron shows the 86% increase of ductility. Also, semi austempered ductile iron shows the higher fatigue limit and lower fatigue crack growth rate as compared with fully austempered ductile iron. By the fractographical analysis, it is revealed that the ferrite obtained by semi austempering process brings about the plastic deformation (ductile striation) of crack tip and gives the prior path of crack propagation. The relatively low crack growth rate in semi austempered specimen is caused by above fractographical reasons

  7. Internal and External Factors Related to Burnout among Iron and Steel Workers: A Cross-Sectional Study in Anshan, China.

    Science.gov (United States)

    Guo, Haiqiang; Guo, Huifang; Yang, Yilong; Sun, Baozhi

    2015-01-01

    Burnout is a syndrome of emotional exhaustion, cynicism and reduced professional efficacy, which can result from long-term work stress. Although the burnout level is high among iron and steel workers, little is known concerning burnout among iron and steel worker. This study aimed to evaluate the burnout and to explore its associated internal and external factors in iron and steel workers. A cross-sectional survey was conducted in iron and steel workers at the Anshan iron-steel complex in Anshan, northeast China. Self-administered questionnaires were distributed to 1,600 workers, and finally 1,300 questionnaires were returned. Burnout was measured using the Chinese version of the Maslach Burnout Inventory-General Survey (MBI-GS). Effort-reward imbalance (ERI), perceived organizational support (POS), and psychological capital (PsyCap) were measured anonymously. A hierarchical regression model was applied to explore the internal and external factors associated with burnout. Mean MBI-GS scores were 13.11±8.06 for emotional exhaustion, 6.64±6.44 for cynicism, and 28.96±10.39 for professional efficacy. Hierarchical linear regression analysis showed that ERI and POS were the most powerful predictors for emotional exhaustion and cynicism, and PsyCap was the most robust predictor for high professional efficacy. Chinese iron and steel workers have a high level of burnout. Burnout might be associated with internal and external factors, including ERI, POS, and PsyCap. Further studies are recommended to develop an integrated model including both internal and external factors, to reduce the level of ERI, and improve POS and workers' PsyCap, thereby alleviating the level of burnout among iron and steel workers.

  8. Internal and External Factors Related to Burnout among Iron and Steel Workers: A Cross-Sectional Study in Anshan, China.

    Directory of Open Access Journals (Sweden)

    Haiqiang Guo

    Full Text Available Burnout is a syndrome of emotional exhaustion, cynicism and reduced professional efficacy, which can result from long-term work stress. Although the burnout level is high among iron and steel workers, little is known concerning burnout among iron and steel worker. This study aimed to evaluate the burnout and to explore its associated internal and external factors in iron and steel workers.A cross-sectional survey was conducted in iron and steel workers at the Anshan iron-steel complex in Anshan, northeast China. Self-administered questionnaires were distributed to 1,600 workers, and finally 1,300 questionnaires were returned. Burnout was measured using the Chinese version of the Maslach Burnout Inventory-General Survey (MBI-GS. Effort-reward imbalance (ERI, perceived organizational support (POS, and psychological capital (PsyCap were measured anonymously. A hierarchical regression model was applied to explore the internal and external factors associated with burnout.Mean MBI-GS scores were 13.11±8.06 for emotional exhaustion, 6.64±6.44 for cynicism, and 28.96±10.39 for professional efficacy. Hierarchical linear regression analysis showed that ERI and POS were the most powerful predictors for emotional exhaustion and cynicism, and PsyCap was the most robust predictor for high professional efficacy.Chinese iron and steel workers have a high level of burnout. Burnout might be associated with internal and external factors, including ERI, POS, and PsyCap. Further studies are recommended to develop an integrated model including both internal and external factors, to reduce the level of ERI, and improve POS and workers' PsyCap, thereby alleviating the level of burnout among iron and steel workers.

  9. Dietary iron intake, iron status, and gestational diabetes.

    Science.gov (United States)

    Zhang, Cuilin; Rawal, Shristi

    2017-12-01

    Pregnant women are particularly vulnerable to iron deficiency and related adverse pregnancy outcomes and, as such, are routinely recommended for iron supplementation. Emerging evidence from both animal and population-based studies, however, has raised potential concerns because significant associations have been observed between greater iron stores and disturbances in glucose metabolism, including increased risk of type 2 diabetes among nonpregnant individuals. Yet, the evidence is uncertain regarding the role of iron in the development of gestational diabetes mellitus (GDM), a common pregnancy complication which has short-term and long-term adverse health ramifications for both women and their children. In this review, we critically and systematically evaluate available data examining the risk of GDM associated with dietary iron, iron supplementation, and iron status as measured by blood concentrations of several indicators. We also discuss major methodologic concerns regarding the available epidemiologic studies on iron and GDM. © 2017 American Society for Nutrition.

  10. Reduction of electric power consumption in relation to household appliances. Elbesparelser ved husholdningsapparater; Forprojekt

    Energy Technology Data Exchange (ETDEWEB)

    Gydesen, A.

    1989-07-15

    Possibilities were investigated for the reduction of electric power consumption in relation to household appliances, and for cooperation with manufacturers in this respect. It is suggested that in the cases of washing-up machines, and washing and drying machines, hot water from the tap could be utilized. This would mean that the energy consumption would then shift to domestic heating equipment, dual-purpose power plants and district heating plants. Ovens, drying machines, washing machines and washing-up machines could use natural gas, especially in areas where this fuel could be conveyed to each household via pipes. Cooperation with manufacturers seems feasible, especially with regard to electric ovens, saucepans for use in combination with the latter, and water beds. Considering future developments, it is reasonable to expect that ultra sound will be utilized in connection with washing-up and washing machines, moreover it is likely that the use of enzymes in washing powders will mean that washing machines will be able to run on cold water. (AB) 21 refs.

  11. Photo-reduction on the rupture of disulfide bonds and the related protein assembling

    Science.gov (United States)

    Wang, Wei

    It has been found that many proteins can self-assemble into nanoscale assemblies when they unfold or partially unfold under harsh conditions, such as low pH, high temperature, or the presence of denaturants, and so on. These nanoscale assemblies can have some applications such as the drug-delivery systems (DDSs). Here we report a study that a very physical way, the UV illumination, can be used to facilitate the formation of protein fibrils and nanoparticles under native conditions by breaking disulfide bonds in some disulfide-containing proteins. By controlling the intensity of UV light and the illumination time, we realized the preparation of self-assembly nanoparticles which encapsulate the anticancer drug doxorubicin (DOX) and can be used as the DDS for inhibiting the growth of tumor. The formation of fibrillary assemblies was also observed. The rupture of disulfide bonds through photo-reduction process due to the effect of tryptophan and tyrosine was studied, and the physical mechanism of the assembling of the related disulfide-containing proteins was also discussed. We thank the financial support from NSF of China and the 973 project.

  12. Global Reduction in HIV-related Maternal Mortality: ART as a Key Strategy

    Directory of Open Access Journals (Sweden)

    Hamisu M. Salihu, MD, PhD

    2015-12-01

    Full Text Available Dr. Holtz and colleagues present a synthesis of evidence from published studies over the previous decade on the collective impact of HIV-targeted interventions on maternal mortality. Amongst an assortment of interventions [that include antiretroviral therapy (ART, micronutrients (multivitamins, vitamin A and selenium, and antibiotics], only ART reduced maternal mortality among HIV-infected pregnant and post-partum mothers. These findings have fundamental and global strategic implications. They are also timely since they provide the evidence that ART reduces HIV-related maternal mortality, and by further enhancing access to ART in HIV-challenged and poor regions of the world, significant improvement in maternal morbidity and mortality indices could be attained. The paper bears good tidings and sound scientific proof that the financial investment made globally by government and non-governmental organizations and agencies to reduce the global burden of HIV/AIDS primarily by making ART more accessible to regions of the world most affected by the epidemic is beginning to show beneficial effects not only in terms of numerical reductions in the rates of new cases of HIV/AIDS among women, but also in maternal mortality levels.

  13. Evaluation of Nitrate and Nitrite Reduction Kinetics Related to Liquid-Air-Interface Corrosion

    International Nuclear Information System (INIS)

    Li, Xiaoji; Gui, F.; Cong, Hongbo; Brossia, C.S.; Frankel, G.S.

    2014-01-01

    Liquid-air interface (LAI) corrosion has been a concern for causing leaks in the carbon steel tanks used for holding high-level radioactive liquid waste. To assist in understanding the mechanism of LAI corrosion, the kinetics of nitrate and nitrite reduction reactions were investigated electrochemically. Cyclic voltammetry and cathodic polarization measurements indicated that the nitrite reduction reaction exhibited faster kinetics than the nitrate reduction reaction at higher cathodic overpotential. However, the primary reduction reaction at the open circuit potential under aerated conditions was the oxygen reduction reaction. The reduction of residual oxygen was also the dominant cathodic reaction at open circuit potential in deaerated conditions. Moreover, the kinetics of oxygen reduction on steel electrodes were significantly influenced by the sample immersion conditions (partial vs. full) for aerated liquid nuclear waste simulants, but not for deaerated conditions. Lastly, the gaseous products formed during LAI corrosion were analyzed using the gas detector tube method and gas chromatography-mass spectrometry and found to contain NH 3 , NO 2 and NO. However, the results suggested that these products were caused by the local acidification generated by the hydrolysis of cations after LAI corrosion underwent extensive propagation, instead of being directly reduced in alkaline conditions. Thus, the results in this work showed that the kinetics of nitrate and nitrite reduction could not generate a salt concentration cell in the meniscus region to cause LAI corrosion

  14. Laypersons' understanding of relative risk reductions: Randomised cross-sectional study

    Directory of Open Access Journals (Sweden)

    Kristiansen Ivar S

    2008-07-01

    Full Text Available Abstract Background Despite increasing recognition of the importance of involving patients in decisions on preventive healthcare interventions, little is known about how well patients understand and utilise information provided on the relative benefits from these interventions. The aim of this study was to explore whether lay people can discriminate between preventive interventions when effectiveness is presented in terms of relative risk reduction (RRR, and whether such discrimination is influenced by presentation of baseline risk. Methods The study was a randomised cross-sectional interview survey of a representative sample (n = 1,519 of lay people with mean age 59 (range 40–98 years in Denmark. In addition to demographic information, respondents were asked to consider a hypothetical drug treatment to prevent heart attack. Its effectiveness was randomly presented as RRR of 10, 20, 30, 40, 50 or 60 percent, and half of the respondents were presented with quantitative information on the baseline risk of heart attack. The respondents had also been asked whether they were diagnosed with hypercholesterolemia or had experienced a heart attack. Results In total, 873 (58% of the respondents consented to the hypothetical treatment. While 49% accepted the treatment when RRR = 10%, the acceptance rate was 58–60% for RRR>10. There was no significant difference in acceptance rates across respondents irrespective of whether they had been presented with quantitative information on baseline risk or not. Conclusion In this study, lay people's decisions about therapy were only slightly influenced by the magnitude of the effect when it was presented in terms of RRR. The results may indicate that lay people have difficulties in discriminating between levels of effectiveness when they are presented in terms of RRR.

  15. Iron overload in lower international prognostic scoring system risk patients with myelodysplastic syndrome receiving red blood cell transfusions: Relation to infections and possible benefit of iron chelation therapy.

    Science.gov (United States)

    Wong, Colleen A C; Wong, Shannon A Y; Leitch, Heather A

    2018-04-01

    An increased incidence of infections and infectious mortality has been reported in myelodysplastic syndromes (MDS) patients receiving red blood cell (RBC) transfusions. We examined incidence of infections requiring antibiotics, antifungal or antiviral medications in transfused lower International Prognostic Scoring System (IPSS) risk MDS patients and whether this differed with iron chelation therapy (ICT). 138 transfused MDS patients were lower IPSS risk. 59 received ICT; median duration was 13 months. There was no significant difference between groups in neutrophil count at first RBC transfusion or first infection. Infections included: bacterial, n = 88; viral; fungal; and mycobacterial; n = 2 each. In ICT and non-ICT patients, respectively, infections were (number [%]): patients, 23 (40.0%) and 22 (27.8%); episodes (median [range]), 2 (1-6) and 2 (1-5); hospitalizations, 16 (27.1%) and 8 (10.1%); and deaths, 0 (0%) and 1 (1.3%), p = NS for all. Median overall survival (OS) from first RBC transfusion was superior in ICT patients, p = 0.01, and remained significant in a multivariate analysis (MVA), p = 0.003. Median time to first infection (TTI) was 27 and 7.8 months, respectively, p < 0.0001, and ICT remained significant for TTI in an MVA, p = 0.02, hazard ratio 0.3. For ICT patients with blast count <5%, TTI was significantly superior (p = 0.004). In this retrospective analysis, for lower IPSS risk MDS patients receiving RBC transfusions, though number and type of infections were similar between groups and despite similar neutrophil counts, time to first infection was significantly longer in ICT patients (p < 0.0001). These results should be confirmed in larger, prospective analyses. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Energy-related CO_2 emission in European Union agriculture: Driving forces and possibilities for reduction

    International Nuclear Information System (INIS)

    Li, Tianxiang; Baležentis, Tomas; Makutėnienė, Daiva; Streimikiene, Dalia; Kriščiukaitienė, Irena

    2016-01-01

    Highlights: • The research focuses on agricultural sectors of the eighteen European countries. • The main drivers of energy-related CO_2 emission are quantified by means of IDA. • The slack-based DEA model is applied to gauge the environmental efficiency. • Shadow prices of carbon emission are analysed. • Energy efficiency remains the primary means for increasing environmental efficiency. - Abstract: Climate change mitigation is a key issue in formulating global environmental policies. Energy production and consumption are the main sources of greenhouse gas (GHG) emissions in Europe. Energy consumption and energy-related GHG emissions from agriculture are an important concern for policymakers, as the agricultural activities should meet food security goals along with proper economic, environmental, and social impacts. Carbon dioxide (CO_2) emission is the most significant among energy-related GHG emissions. This paper analyses the main drivers behind energy-related CO_2 emission across agricultural sectors of European countries. The analysis is based on aggregate data from the World Input-Output Database. The research explores two main directions. Firstly, Index Decomposition Analysis (IDA), facilitated by the Shapley index, is used to identify the main drivers of CO_2 emission. Secondly, the Slack-based Model (SBM) is applied to gauge the environmental efficiency of European agricultural sectors. By applying frontier techniques, we also derive the measures of environmental efficiency and shadow prices, thereby contributing to a discussion on CO_2 emission mitigation in agriculture. Therefore, the paper devises an integrated approach towards analysis of CO_2 emission based upon advanced decomposition and efficiency analysis models. The research covers eighteen European countries and the applied methodology decomposes contributions to CO_2 emission across of regions and factors. Results of IDA suggest that decreasing energy intensity is the main factor

  17. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Health [NIH]) Heavy Menstrual Bleeding (Centers for Disease Control and Prevention) Iron - Health Professional Fact ... Email Alerts Receive automatic alerts about NHLBI related news and highlights from ...

  18. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Treatment will explain treatment-related complications or side effects. Diagnosis Iron-deficiency anemia may be detected during ... to your doctor if you are experiencing side effects such as a bad metallic taste, vomiting, diarrhea, ...

  19. Measurement of iron absorption from meals contaminated with iron

    International Nuclear Information System (INIS)

    Hallberg, L.; Bjoern-Rasmussen, E.

    1981-01-01

    A method is described to measure in vitro the extent of isotopic exchange between the native nonheme food iron and added inorganic reduction to radioiron tracer. The food is digested with pepsin and trypsin in the presence of radioiron. The exchangeability of food iron is calculated from the specific activity in the food and in an extract of bathophenantroline in isoamyl alcohol obtained after digesting this food. The precision and accuracy of the method is illustrated by two kinds of studies, those in which different amounts of contamination iron are added to a meal and those evaluating contamination iron in natural meals. The present method will make it possible to measure validly iron absorption from meals contaminated with unknown amounts of iron of unknown exchangeability with the extrinsic radioiron tracer

  20. The effect of ammonium chloride and urea application on soil bacterial communities closely related to the reductive transformation of pentachlorophenol.

    Science.gov (United States)

    Yu, Huan-Yun; Wang, Yong-kui; Chen, Peng-cheng; Li, Fang-bai; Chen, Man-jia; Hu, Min

    2014-05-15

    Pentachlorophenol (PCP) is widely distributed in the soil, and nitrogen fertilizer is extensively used in agricultural production. However, studies on the fate of organic contaminants as affected by nitrogen fertilizer application have been rare and superficial. The present study aimed to examine the effect of ammonium chloride (NH4Cl) and urea (CO(NH2)2) application on the reductive transformation of PCP in a paddy soil. The study showed that the addition of low concentrations of NH4Cl/CO(NH2)2 enhanced the transformation of PCP, while the addition of high concentrations of NH4Cl/CO(NH2)2 had the opposite effect. The variations in the abundance of soil microbes in response to NH4Cl/CO(NH2)2 addition showed that both NH4Cl and CO(NH2)2 had inhibitory effects on the growth of dissimilatory iron-reducing bacteria (DIRB) of the genus Comamonas. In contrast, for the genus Shewanella, low concentrations of NH4Cl inhibited growth, and high concentrations of NH4Cl enhanced growth, whereas all concentrations of CO(NH2)2 showed enhancement effects. In addition, consistent patterns of variation were found between the abundances of dechlorinating bacteria in the genus Dehalobacter and PCP transformation rates under NH4Cl/CO(NH2)2 addition. In conclusion, nitrogen application produced variations in the structure of the soil microbial community, especially in the abundance of dissimilatory iron-reducing bacteria and dechlorinating bacteria, which, in turn, affected PCP dechlorination. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Studies on Ancylostomiasis: II.Clinical Symptomatology, Effects of Drugs, especially of Iron Compounds, with Relation to the Severity of Artificial Infection

    International Nuclear Information System (INIS)

    Lee, Mun Ho; Kim, Dong Jip; Lee, Jang Kyu; Seo, Byong Sul

    1967-01-01

    This study was aimed; firstly to observe various clinical symptomatology with relation to the number of Ancylostoma duodenale larvae orally given to the human beings, secondly to evaluate the effects of some drugs like steroid hormones, antihistaminics and antitussives, and, thirdly to study the influences of some iron compounds in prevention and treatment of anemia of such origin. Ten healthy volunteers free from the previous history of hookworm infection were divided into 4 groups, to whom various numbers of actively moving filariform Ancylostoma duodenale larvae were orally given; 500 to 4 cases, 250 to 3 cases and 100 to 3 cases. Following were the results: 1. Clinical symptomatology. 1) The most frequently encountered symptoms and signs were general malaise, cough and hoarseness. The tracheal itching and pain, low back pain, arthralgia, sputum and salivation, acid belching, loss of appetite, abdominal pain and vomiting were also noted. 2) If the larger number of the larvae was given, the clinical symptomatology was more severe. 3) Prednisolone medication caused some improvement of such symptomatology, while the antihistaminics and antitussives like codeine or ephedrine were ineffective. 4) In volunteers whose nutritional conditions were rather poor appeared to show more severe symptomatology. 2. Effects of iron compounds. 1) The oral administration of ferrous fumarate induced a slight increase of serum iron levels in the initial stage of the infection, then a decrease from 15-20 days later and a recovery after 2 months. 2) The intravenous administration of saccharated ferric oxide induced a steady upkeep of the serum iron levels. 3) The hemoglobin contents also showed the upkeeps after either the oral or intravenous administration of the iron compounds. 4) The iron compounds, therefore, are considered to have the preventive as well as the therapeutic effects on hookworm anemia, which may strongly suggest that hookworm anemia is essentially the iron deficiency

  2. Studies on Ancylostomiasis: II.Clinical Symptomatology, Effects of Drugs, especially of Iron Compounds, with Relation to the Severity of Artificial Infection

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Mun Ho; Kim, Dong Jip; Lee, Jang Kyu; Seo, Byong Sul [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1967-09-15

    This study was aimed; firstly to observe various clinical symptomatology with relation to the number of Ancylostoma duodenale larvae orally given to the human beings, secondly to evaluate the effects of some drugs like steroid hormones, antihistaminics and antitussives, and, thirdly to study the influences of some iron compounds in prevention and treatment of anemia of such origin. Ten healthy volunteers free from the previous history of hookworm infection were divided into 4 groups, to whom various numbers of actively moving filariform Ancylostoma duodenale larvae were orally given; 500 to 4 cases, 250 to 3 cases and 100 to 3 cases. Following were the results: 1. Clinical symptomatology. 1) The most frequently encountered symptoms and signs were general malaise, cough and hoarseness. The tracheal itching and pain, low back pain, arthralgia, sputum and salivation, acid belching, loss of appetite, abdominal pain and vomiting were also noted. 2) If the larger number of the larvae was given, the clinical symptomatology was more severe. 3) Prednisolone medication caused some improvement of such symptomatology, while the antihistaminics and antitussives like codeine or ephedrine were ineffective. 4) In volunteers whose nutritional conditions were rather poor appeared to show more severe symptomatology. 2. Effects of iron compounds. 1) The oral administration of ferrous fumarate induced a slight increase of serum iron levels in the initial stage of the infection, then a decrease from 15-20 days later and a recovery after 2 months. 2) The intravenous administration of saccharated ferric oxide induced a steady upkeep of the serum iron levels. 3) The hemoglobin contents also showed the upkeeps after either the oral or intravenous administration of the iron compounds. 4) The iron compounds, therefore, are considered to have the preventive as well as the therapeutic effects on hookworm anemia, which may strongly suggest that hookworm anemia is essentially the iron deficiency

  3. Breast Cancer-Related Arm Lymphedema: Incidence Rates, Diagnostic Techniques, Optimal Management and Risk Reduction Strategies

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Chirag [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI (United States); Vicini, Frank A., E-mail: fvicini@beaumont.edu [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI (United States)

    2011-11-15

    As more women survive breast cancer, long-term toxicities affecting their quality of life, such as lymphedema (LE) of the arm, gain importance. Although numerous studies have attempted to determine incidence rates, identify optimal diagnostic tests, enumerate efficacious treatment strategies and outline risk reduction guidelines for breast cancer-related lymphedema (BCRL), few groups have consistently agreed on any of these issues. As a result, standardized recommendations are still lacking. This review will summarize the latest data addressing all of these concerns in order to provide patients and health care providers with optimal, contemporary recommendations. Published incidence rates for BCRL vary substantially with a range of 2-65% based on surgical technique, axillary sampling method, radiation therapy fields treated, and the use of chemotherapy. Newer clinical assessment tools can potentially identify BCRL in patients with subclinical disease with prospective data suggesting that early diagnosis and management with noninvasive therapy can lead to excellent outcomes. Multiple therapies exist with treatments defined by the severity of BCRL present. Currently, the standard of care for BCRL in patients with significant LE is complex decongestive physiotherapy (CDP). Contemporary data also suggest that a multidisciplinary approach to the management of BCRL should begin prior to definitive treatment for breast cancer employing patient-specific surgical, radiation therapy, and chemotherapy paradigms that limit risks. Further, prospective clinical assessments before and after treatment should be employed to diagnose subclinical disease. In those patients who require aggressive locoregional management, prophylactic therapies and the use of CDP can help reduce the long-term sequelae of BCRL.

  4. Breast Cancer-Related Arm Lymphedema: Incidence Rates, Diagnostic Techniques, Optimal Management and Risk Reduction Strategies

    International Nuclear Information System (INIS)

    Shah, Chirag; Vicini, Frank A.

    2011-01-01

    As more women survive breast cancer, long-term toxicities affecting their quality of life, such as lymphedema (LE) of the arm, gain importance. Although numerous studies have attempted to determine incidence rates, identify optimal diagnostic tests, enumerate efficacious treatment strategies and outline risk reduction guidelines for breast cancer–related lymphedema (BCRL), few groups have consistently agreed on any of these issues. As a result, standardized recommendations are still lacking. This review will summarize the latest data addressing all of these concerns in order to provide patients and health care providers with optimal, contemporary recommendations. Published incidence rates for BCRL vary substantially with a range of 2–65% based on surgical technique, axillary sampling method, radiation therapy fields treated, and the use of chemotherapy. Newer clinical assessment tools can potentially identify BCRL in patients with subclinical disease with prospective data suggesting that early diagnosis and management with noninvasive therapy can lead to excellent outcomes. Multiple therapies exist with treatments defined by the severity of BCRL present. Currently, the standard of care for BCRL in patients with significant LE is complex decongestive physiotherapy (CDP). Contemporary data also suggest that a multidisciplinary approach to the management of BCRL should begin prior to definitive treatment for breast cancer employing patient-specific surgical, radiation therapy, and chemotherapy paradigms that limit risks. Further, prospective clinical assessments before and after treatment should be employed to diagnose subclinical disease. In those patients who require aggressive locoregional management, prophylactic therapies and the use of CDP can help reduce the long-term sequelae of BCRL.

  5. Age-Related Reduction of Recovery Sleep and Arousal Threshold in Drosophila

    Science.gov (United States)

    Vienne, Julie; Spann, Ryanne; Guo, Fang; Rosbash, Michael

    2016-01-01

    Study Objectives: Physiological studies show that aging affects both sleep quality and quantity in humans, and sleep complaints increase with age. Along with knowledge about the negative effects of poor sleep on health, understanding the enigmatic relationship between sleep and aging is important. Because human sleep is similar to Drosophila (fruit fly) sleep in many ways, we addressed the effects of aging on sleep in this model organism. Methods: Baseline sleep was recorded in five different Drosophila genotypes raised at either 21°C or 25°C. The amount of sleep recovered was then investigated after a nighttime of sleep deprivation (12 h) and after chronic sleep deprivation (3 h every night for multiple nights). Finally, the effects of aging on arousal, namely, sensitivity to neuronal and mechanical stimuli, were studied. Results: We show that fly sleep is affected by age in a manner similar to that of humans and other mammals. Not only do older flies of several genotypes have more fragmented sleep and reduced total sleep time compared to young flies, but older flies also fail to recover as much sleep after sleep deprivation. This suggests either lower sleep homeostasis and/or a failure to properly recover sleep. Older flies also show a decreased arousal threshold, i.e., an increased response to neuronal and mechanical wake-promoting stimuli. The reduced threshold may either reflect or cause the reduced recovery sleep of older flies compared to young flies after sleep deprivation. Conclusions: Further studies are certainly needed, but we suggest that the lower homeostatic sleep drive of older flies causes their decreased arousal threshold. Citation: Vienne J, Spann R, Guo F, Rosbash M. Age-related reduction of recovery sleep and arousal threshold in Drosophila. SLEEP 2016;39(8):1613–1624. PMID:27306274

  6. Iron Coordination and Halogen-Bonding Assisted Iodosylbenzene Activation

    DEFF Research Database (Denmark)

    Wegeberg, Christina; Poulsen de Sousa, David; McKenzie, Christine

    catalytic mixtures using soluble terminal oxygen transfer agents. Isolation of a reactive iron-terminal oxidant adduct, an unique Fe(III)-OIPh complex, is facilitated by strong stabilizing supramolecular halogen-bonding. L3-edge XANES suggests +1.6 for the average oxidation state for the iodine atom3......The iron complex of the hexadentate ligand N,N,N'-tris(2-pyridylmethyl)ethylendiamine-N'-acetate (tpena) efficiently catalyzes selective oxidations of electron-rich olefins and sulfides by insoluble iodosylbenzene (PhIO). Surprisingly, these reactions are faster and more selective than homogenous...... in the iron(III)-coordinated PhIO. This represents a reduction of iodine relative to the original “hypervalent” (+3) PhIO. The equivalent of electron density must be removed from the {(tpena)Fe(III)O} moiety, however Mössbauer spectroscopy shows that the iron atom is not high valent....

  7. Supercompactor force effectiveness as related to dry active waste volume reduction

    International Nuclear Information System (INIS)

    Williams, P.C.; Phillips, W.S.

    1986-01-01

    The first U.S. permanently installed supercompactor is now in operation at the Babcock and Wilcox volume reduction center, Parks Township, Pennsylvania. Tests with various DAW (dry active waste) material have been conducted, recording press force versus drum height as one means of estimating volume reduction capability of this machine at various compaction forces. The results of these tests, as well as other factors, are presented herein

  8. Consumer-supplier-government triangular relations. Rethinking the UK policy path for carbon emissions reduction from the UK residential sector

    Energy Technology Data Exchange (ETDEWEB)

    Parag, Yael; Darby, Sarah [Environmental Change Institute, University of Oxford, OUCE, South Parks Road, Oxford OX1 3QY (United Kingdom)

    2009-10-15

    The UK residential (household) sector is responsible for approximately 30% of total carbon dioxide emissions and is often seen as the most promising in terms of early reductions. As most direct household emissions come from only two fuel sources, this paper critically examines how existing emissions reduction policies for the sector shape - and are shaped by - relations between the three main groups of actor in this policy domain: central government, gas and electricity suppliers, and energy users. Focusing on relations between three dyads (government-suppliers, suppliers-consumers and consumers-government) enables us to examine aspects of demand reduction that have often been overlooked to date. By 'relations' we refer to services, power relationships and flows of capital and information, as well as less easily defined elements such as loyalty, trust and accountability. The paper argues that the chosen government policy path to deliver demand reduction, which heavily emphasises the suppliers' role, suffers from principal-agent problems, fails to align consumers and supplier interests toward emissions reduction, and does not yet portray a lower-carbon future in positive terms. It suggests that more attention should be paid to government-consumer relations, recognising that energy consumers are also citizens. (author)

  9. Consumer-supplier-government triangular relations: Rethinking the UK policy path for carbon emissions reduction from the UK residential sector

    Energy Technology Data Exchange (ETDEWEB)

    Parag, Yael [Environmental Change Institute, University of Oxford, OUCE, South Parks Road, Oxford OX1 3QY (United Kingdom)], E-mail: yael.parag@ouce.ox.ac.uk; Darby, Sarah [Environmental Change Institute, University of Oxford, OUCE, South Parks Road, Oxford OX1 3QY (United Kingdom)

    2009-10-15

    The UK residential (household) sector is responsible for approximately 30% of total carbon dioxide emissions and is often seen as the most promising in terms of early reductions. As most direct household emissions come from only two fuel sources, this paper critically examines how existing emissions reduction policies for the sector shape - and are shaped by - relations between the three main groups of actor in this policy domain: central government, gas and electricity suppliers, and energy users. Focusing on relations between three dyads (government-suppliers, suppliers-consumers and consumers-government) enables us to examine aspects of demand reduction that have often been overlooked to date. By 'relations' we refer to services, power relationships and flows of capital and information, as well as less easily defined elements such as loyalty, trust and accountability. The paper argues that the chosen government policy path to deliver demand reduction, which heavily emphasises the suppliers' role, suffers from principal-agent problems, fails to align consumers and supplier interests toward emissions reduction, and does not yet portray a lower-carbon future in positive terms. It suggests that more attention should be paid to government-consumer relations, recognising that energy consumers are also citizens.

  10. Consumer-supplier-government triangular relations: Rethinking the UK policy path for carbon emissions reduction from the UK residential sector

    International Nuclear Information System (INIS)

    Parag, Yael; Darby, Sarah

    2009-01-01

    The UK residential (household) sector is responsible for approximately 30% of total carbon dioxide emissions and is often seen as the most promising in terms of early reductions. As most direct household emissions come from only two fuel sources, this paper critically examines how existing emissions reduction policies for the sector shape - and are shaped by - relations between the three main groups of actor in this policy domain: central government, gas and electricity suppliers, and energy users. Focusing on relations between three dyads (government-suppliers, suppliers-consumers and consumers-government) enables us to examine aspects of demand reduction that have often been overlooked to date. By 'relations' we refer to services, power relationships and flows of capital and information, as well as less easily defined elements such as loyalty, trust and accountability. The paper argues that the chosen government policy path to deliver demand reduction, which heavily emphasises the suppliers' role, suffers from principal-agent problems, fails to align consumers and supplier interests toward emissions reduction, and does not yet portray a lower-carbon future in positive terms. It suggests that more attention should be paid to government-consumer relations, recognising that energy consumers are also citizens.

  11. Further Reductions in Road-Related Deaths and Injuries in Irish Children

    LENUS (Irish Health Repository)

    Garry, E

    2018-04-01

    The aim was to study road-related injuries and fatalities in under 15-year-olds in three time periods (1996-2000, 2004-2008 and 2009 -2013 respectively) to assess whether progress has been made via cross-sectoral efforts (legislation, public awareness campaigns and police enforcement) to reduce this injury toll in Ireland. For road traffic collisions where an injury has occurred, police assistance is required and at the time a detailed CT 68 form is completed by the attending police officer and sent to the Road Safety Authority for analysis. Details regarding the severity of injury, light and road conditions and safety measures such as seat belt or car restraint use, seat position and helmet use if a cyclist is involved are recorded. Injuries were sub-classified as fatalities, serious (detained in hospital, fractures, severe head injury, severe internal injuries or shock requiring treatment) or minor. All data for the three time periods was entered onto an SPSS database. A concerted national campaign re road safety media campaign allied to random breath testing, penalty points for driving offences, on the spot fines for speeding and greater police enforcement took place over the 17-year timeframe and continues to this day. When results were compared between the three cohorts, total injuries dropped from 5928 (1996-2000) to 3903 (2009-2013).Fatal injuries dropped from 163 to 43 with car occupant fatalities fell from 69 to 17 between 1996-2000 and 2009-2013. Serious injuries dropped from 347 in the first cohort to 201 in the third cohort. Minor injuries fell from 5,063 to 3,659 between first and last cohort. Pedestrian injuries dropped from 1719 to 1258 with pedestrian fatalities decreased from 61 (1996-2000) to 21 (2009-2013) and serious pedestrian injuries decreased from 261 down to 129. Cyclist fatalities saw the most significant fall (76%) with a dramatic reduction in fatalities from 25 down to 6. A national road safety campaign, greater police enforcement and a

  12. Reduction of 3-methoxytyramine concentrations in the caudate nucleus of rats after exposure to high-energy iron particles: evidence for deficits in dopaminergic neurons

    International Nuclear Information System (INIS)

    Hunt, W.A.; Dalton, T.K.; Joseph, J.A.; Rabin, B.M.

    1990-01-01

    Exposure to low doses of high-energy iron particles can alter motor behavior. The ability of rats to hang from a wire has been reported to be significantly degraded after exposure to doses as low as 0.5 Gy. In addition, deficits in the ability of acetylcholine to regulate dopamine release in the caudate nucleus (an area in the brain important for motor function) have been found. The concentrations of 3-methoxytyramine (3-MT), a metabolite of dopamine whose concentrations reflect dopamine release in vivo, were measured after rats were exposed to different doses of high-energy iron particles to gain further information about the effect of radiation on the dopaminergic system. Concentrations of 3-MT were significantly reduced 3 days after exposure to 5 Gy but returned to control values by 8 days. After 6 months, concentrations were again less than control values. Exposure to 5 Gy of high-energy electrons or gamma photons had no effect 3 days after exposure. Very high doses of electrons were needed to alter 3-MT concentrations. One hundred grays of electrons decreased 3-MT 30 min after irradiation but levels returned to control values by 60 min. Gamma photons had no effect after doses up to 200 Gy. These results provide further evidence that exposure to heavy particles can degrade motor behavior through an action on dopaminergic mechanisms and that this can occur after doses much lower than those needed for low-LET radiation

  13. A new method to produce nanoscale iron for nitrate removal

    International Nuclear Information System (INIS)

    Chen, S.-S.; Hsu, H.-D.; Li, C.-W.

    2004-01-01

    This article proposes a novel technology combining electrochemical and ultrasonic methods to produce nanoscale zero valent iron (NZVI). With platinum placed in the cathode and the presence of the dispersion agent, 0.2g/l cetylpyridinium chloride (CPC), a cation surfactant, in the solution, the nanoscale iron particle was successfully produced with diameter of 1-20 nm and specific surface area of 25.4m 2 /g. The produced NZVI was tested in batch experiments for nitrate removal. The results showed that the nitrate reduction was affected by pH. Al low pH, nitrate was shown faster decline and more reduction in term of g NO 3 - -N/g NZVI. The reaction was first order and kinetic coefficients for the four pHs were directly related to pH with R 2 >0.95. Comparing with microscale zero-valent iron (45μm, 0.183m 2 /g), microscale zero-valent iron converted nitrate to ammonia completely, but NZVI converted nitrate to ammonia partially from 36.2 to 45.3% dependent on pH. For mass balance of iron species, since the dissolved iron in the solution was very low ( 2 O 3 was recognized. Thus the reaction mechanisms can be determined

  14. Variety in cereal cultivation in the Late Bronze and Early Iron Ages in relation to environmental conditions

    Czech Academy of Sciences Publication Activity Database

    Dreslerová, Dagmar; Kočár, Petr; Chuman, T.; Šefrna, L.; Poništiak, Š.

    2013-01-01

    Roč. 40, č. 4 (2013), s. 1988-2000 ISSN 0305-4403 Institutional research plan: CEZ:AV0Z80020508 Institutional support: RVO:67985912 Keywords : crop husbandry * charred cereal grains * environment * weather * soil s * Late Bronze Age/Early Iron Age Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 2.139, year: 2013

  15. Iron Deficiency Anemia in Relation to Respiratory Disease and Social Behaviors In Low-Income Infants in France.

    Science.gov (United States)

    Honig, Alice Sterling

    1993-01-01

    Examined a sample of 177 infants (age 9 through 12 months) with iron deficiency anemia (IDA) from low-income French, African, and North African Muslim families in Paris. Found a higher than normal incidence of otitis media and respiratory diseases such as bronchitis among the infants. Also examined the relationship between infant IDA and child…

  16. Peroxo-Type Intermediates in Class I Ribonucleotide Reductase and Related Binuclear Non-Heme Iron Enzymes

    DEFF Research Database (Denmark)

    Kepp, Kasper Planeta; Bell, Caleb B.; Clay, MIchael D.

    2009-01-01

    We have performed a systematic study of chemically possible peroxo-type intermediates occurring in the non-heme di-iron enzyme class la ribonucleotide reductase, using spectroscopically calibrated computational chemistry. Density functional computations of equilibrium structures, Fe-O and O-O str...

  17. Predicting Structure-Function Relations and Survival following Surgical and Bronchoscopic Lung Volume Reduction Treatment of Emphysema.

    Science.gov (United States)

    Mondoñedo, Jarred R; Suki, Béla

    2017-02-01

    Lung volume reduction surgery (LVRS) and bronchoscopic lung volume reduction (bLVR) are palliative treatments aimed at reducing hyperinflation in advanced emphysema. Previous work has evaluated functional improvements and survival advantage for these techniques, although their effects on the micromechanical environment in the lung have yet to be determined. Here, we introduce a computational model to simulate a force-based destruction of elastic networks representing emphysema progression, which we use to track the response to lung volume reduction via LVRS and bLVR. We find that (1) LVRS efficacy can be predicted based on pre-surgical network structure; (2) macroscopic functional improvements following bLVR are related to microscopic changes in mechanical force heterogeneity; and (3) both techniques improve aspects of survival and quality of life influenced by lung compliance, albeit while accelerating disease progression. Our model predictions yield unique insights into the microscopic origins underlying emphysema progression before and after lung volume reduction.

  18. Genomic Organization and Expression of Iron Metabolism Genes in the Emerging Pathogenic Mold Scedosporium apiospermum

    Directory of Open Access Journals (Sweden)

    Yohann Le Govic

    2018-04-01

    Full Text Available The ubiquitous mold Scedosporium apiospermum is increasingly recognized as an emerging pathogen, especially among patients with underlying disorders such as immunodeficiency or cystic fibrosis (CF. Indeed, it ranks the second among the filamentous fungi colonizing the respiratory tract of CF patients. However, our knowledge about virulence factors of this fungus is still limited. The role of iron-uptake systems may be critical for establishment of Scedosporium infections, notably in the iron-rich environment of the CF lung. Two main strategies are employed by fungi to efficiently acquire iron from their host or from their ecological niche: siderophore production and reductive iron assimilation (RIA systems. The aim of this study was to assess the existence of orthologous genes involved in iron metabolism in the recently sequenced genome of S. apiospermum. At first, a tBLASTn analysis using A. fumigatus iron-related proteins as query revealed orthologs of almost all relevant loci in the S. apiospermum genome. Whereas the genes putatively involved in RIA were randomly distributed, siderophore biosynthesis and transport genes were organized in two clusters, each containing a non-ribosomal peptide synthetase (NRPS whose orthologs in A. fumigatus have been described to catalyze hydroxamate siderophore synthesis. Nevertheless, comparative genomic analysis of siderophore-related clusters showed greater similarity between S. apiospermum and phylogenetically close molds than with Aspergillus species. The expression level of these genes was then evaluated by exposing conidia to iron starvation and iron excess. The expression of several orthologs of A. fumigatus genes involved in siderophore-based iron uptake or RIA was significantly induced during iron starvation, and conversely repressed in iron excess conditions. Altogether, these results indicate that S. apiospermum possesses the genetic information required for efficient and competitive iron uptake

  19. Protein Hydrolysates as Promoters of Non-Haem Iron Absorption

    Science.gov (United States)

    Li, Yanan; Jiang, Han; Huang, Guangrong

    2017-01-01

    Iron (Fe) is an essential micronutrient for human growth and health. Organic iron is an excellent iron supplement due to its bioavailability. Both amino acids and peptides improve iron bioavailability and absorption and are therefore valuable components of iron supplements. This review focuses on protein hydrolysates as potential promoters of iron absorption. The ability of protein hydrolysates to chelate iron is thought to be a key attribute for the promotion of iron absorption. Iron-chelatable protein hydrolysates are categorized by their absorption forms: amino acids, di- and tri-peptides and polypeptides. Their structural characteristics, including their size and amino acid sequence, as well as the presence of special amino acids, influence their iron chelation abilities and bioavailabilities. Protein hydrolysates promote iron absorption by keeping iron soluble, reducing ferric iron to ferrous iron, and promoting transport across cell membranes into the gut. We also discuss the use and relative merits of protein hydrolysates as iron supplements. PMID:28617327

  20. Protein Hydrolysates as Promoters of Non-Haem Iron Absorption

    Directory of Open Access Journals (Sweden)

    Yanan Li

    2017-06-01

    Full Text Available Iron (Fe is an essential micronutrient for human growth and health. Organic iron is an excellent iron supplement due to its bioavailability. Both amino acids and peptides improve iron bioavailability and absorption and are therefore valuable components of iron supplements. This review focuses on protein hydrolysates as potential promoters of iron absorption. The ability of protein hydrolysates to chelate iron is thought to be a key attribute for the promotion of iron absorption. Iron-chelatable protein hydrolysates are categorized by their absorption forms: amino acids, di- and tri-peptides and polypeptides. Their structural characteristics, including their size and amino acid sequence, as well as the presence of special amino acids, influence their iron chelation abilities and bioavailabilities. Protein hydrolysates promote iron absorption by keeping iron soluble, reducing ferric iron to ferrous iron, and promoting transport across cell membranes into the gut. We also discuss the use and relative merits of protein hydrolysates as iron supplements.

  1. A deposit model for magmatic iron-titanium-oxide deposits related to Proterozoic massif anorthosite plutonic suites: Chapter K in Mineral Deposit Models for Resource Assessment

    Science.gov (United States)

    Woodruff, Laurel G.; Nicholson, Suzanne W.; Fey, David L.

    2013-01-01

    This descriptive model for magmatic iron-titanium-oxide (Fe-Ti-oxide) deposits hosted by Proterozoic age massif-type anorthosite and related rock types presents their geological, mineralogical, geochemical, and geoenvironmental attributes. Although these Proterozoic rocks are found worldwide, the majority of known deposits are found within exposed rocks of the Grenville Province, stretching from southwestern United States through eastern Canada; its extension into Norway is termed the Rogaland Anorthosite Province. This type of Fe-Ti-oxide deposit dominated by ilmenite rarely contains more than 300 million tons of ore, with between 10- to 45-percent titanium dioxide (TiO2), 32- to 45-percent iron oxide (FeO), and less than 0.2-percent vanadium (V).

  2. Food Reduction in Avicenna's View and Related Principles in Classical Medicine.

    Science.gov (United States)

    Nozad, Aisan; Naseri, Mohsen; Safari, Mir Bahram; Abd Al Ahadi, Azam; Ghaffari, Farzaneh

    2016-06-01

    Traditional Iranian medicine (TIM) is a rich and valuable school of thought that believes medications are not the only effective approach for the treatment of diseases but that nutrition is also important. Our study includes two parts; the first is a book review of the Canon of Medicine by Avicenna (10th and 11th centuries), in which we focus on finding and understanding Avicenna's point of view. In the second part, we searched for "food reduction" as a key word from 2000 to 2015 in databases such as Google Scholar, PubMed, Copernicus, DOAJ, EBSCO-CINAHL, and the Iranian search database Iranmedex for principles of food reduction in classical medicine. The main methods of treatment in traditional medicine include changes in lifestyle, especially diet, the use of medications, and the use of manipulation methods. For diet, the individual may be prohibited from eating or food amounts may be decreased or increased. Centuries ago, Avicenna was making use of methods of food reduction as an important therapeutic approach in the treatment of diseases. According to him, food reduction, to the extent that it does not cause energy loss helps to cure disease. Avicenna has proposed food reduction as an aid to treating a variety of ailments such as headaches and reflux. Today, a variety of basic and clinical research has shown that food reduction or calorie restriction to a standard level can effectively prevent and treat a variety of diseases such as neoplasms, diabetes, and kidney disease. Practical principles explained by traditional Iranian medicine, in particular Avicenna, could open important and quite uncomplicated strategies for the prevention and treatment of diseases.

  3. Harm reduction and knowledge exchange-a qualitative analysis of drug-related Internet discussion forums.

    Science.gov (United States)

    Soussan, Christophe; Kjellgren, Anette

    2014-09-08

    and how to use them safely. Although this publicly available knowledge could entail an increase in drug use, the main characteristics of the discussions in general were a concern for safety and harm reduction, not for recruiting new users. Drug-related Internet forums could be used as a location for drug prevention, as well as a source of information for further research about NPS.

  4. In situ iron-57 Moessbauer spectroscopic investigations of the effect of titania surface area on the reducibility of titania-supported iron oxide

    International Nuclear Information System (INIS)

    Berry, F.J.; Du Hongzhang

    1990-01-01

    Iron-57 Moessbauer spectroscopy has been used to monitor the reducibility in hydrogen of iron oxides supported on titania of differing surface areas. The results show that although Fe 3+ in the iron oxide supported on low surface area titania (11 m 2 g -1 ) is not amenable to facile reduction at low temperatures, complete reduction to metallic iron is achieved by treatment at 600deg C. The data also show that the extent of reduction at elevated temperatures exceeds that which is obtained on similar silica- and alumina-supported systems. Fe 3+ in iron oxide supported on higher surface area titania (50 m 2 g -1 and 240 m 2 g -1 ) is partially reduced in hydrogen at 235deg C to Fe 2+ but fails to attain complete reduction to the metallic state following treatment at 600deg C. The results are related to the different dispersions of iron oxide which can be attained on titania of differing surface area and the consequent interactions between the support and the supported phases. (orig.)

  5. NF ISO 7097-1. Nuclear fuel technology - Uranium dosimetry in solutions, in uranium hexafluoride and in solids - Part 1: reduction with iron (II) / oxidation with potassium bi-chromate / titration method; NF ISO 7097-1. Technologie du combustible nucleaire. Dosage de l'uranium dans des solutions, l'hexafluorure d'uranium et des solides. Partie 1: reduction par fer (II) / oxydation par bichromate de potassium / methode par titrage

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-04-01

    This standard document describes the mode of operation of three different methods for the quantitative dosimetry of uranium in solutions, in UF{sub 6} and in solids: reduction by iron (II), oxidation by potassium bi-chromate and titration. (J.S.)

  6. Laser surface texturing of cast iron steel: dramatic edge burr reduction and high speed process optimisation for industrial production using DPSS picosecond lasers

    Science.gov (United States)

    Bruneel, David; Kearsley, Andrew; Karnakis, Dimitris

    2015-07-01

    In this work we present picosecond DPSS laser surface texturing optimisation of automotive grade cast iron steel. This application attracts great interest, particularly in the automotive industry, to reduce friction between moving piston parts in car engines, in order to decrease fuel consumption. This is accomplished by partially covering with swallow microgrooves the inner surface of a piston liner and is currently a production process adopting much longer pulse (microsecond) DPSS lasers. Lubricated interface conditions of moving parts require from the laser process to produce a very strictly controlled surface topography around the laser formed grooves, whose edge burr height must be lower than 100 nm. To achieve such a strict tolerance, laser machining of cast iron steel was investigated using an infrared DPSS picosecond laser (10ps duration) with an output power of 16W and a repetition rate of 200 kHz. The ultrashort laser is believed to provide a much better thermal management of the etching process. All studies presented here were performed on flat samples in ambient air but the process is transferrable to cylindrical geometry engine liners. We will show that reducing significantly the edge burr below an acceptable limit for lubricated engine production is possible using such lasers and remarkably the process window lies at very high irradiated fluences much higher that the single pulse ablation threshold. This detailed experimental work highlights the close relationship between the optimised laser irradiation conditions as well as the process strategy with the final size of the undesirable edge burrs. The optimised process conditions are compatible with an industrial production process and show the potential for removing extra post)processing steps (honing, etc) of cylinder liners on the manufacturing line saving time and cost.

  7. New insights into iron deficiency and iron deficiency anemia.

    Science.gov (United States)

    Camaschella, Clara

    2017-07-01

    Recent advances in iron metabolism have stimulated new interest in iron deficiency (ID) and its anemia (IDA), common conditions worldwide. Absolute ID/IDA, i.e. the decrease of total body iron, is easily diagnosed based on decreased levels of serum ferritin and transferrin saturation. Relative lack of iron in specific organs/tissues, and IDA in the context of inflammatory disorders, are diagnosed based on arbitrary cut offs of ferritin and transferrin saturation and/or marker combination (as the soluble transferrin receptor/ferritin index) in an appropriate clinical context. Most ID patients are candidate to traditional treatment with oral iron salts, while high hepcidin levels block their absorption in inflammatory disorders. New iron preparations and new treatment modalities are available: high-dose intravenous iron compounds are becoming popular and indications to their use are increasing, although long-term side effects remain to be evaluated. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Bioavailability & absorption of Iron and Anemia

    Directory of Open Access Journals (Sweden)

    Radhika Kapil

    2018-01-01

    Full Text Available Humans derive iron from their everyday diet, predominantly from plant foods and the rest from foods of animal origin. Iron is found in food as either haem or non-haem iron.  Haem iron, which is about up to 40 per cent of the iron in meat, poultry, and fish, is well absorbed.  All the iron in plants (fruits, vegetables, grains, nuts is in the form of non-haem iron and is relatively poorly absorbed. Non-haem iron contributes about 90-95 per cent of total daily iron in vegan diets. In western countries,the intake of haem iron from meat and meat products accounts for bulk of the dietary iron. The haem iron consumption is minimal in developing countries with majority obtaining non-haem iron from cereals, pulses, vegetables and fruits'. The diets is plagued by low iron content and poor absorption. Major sources of non-haem iron are plant foods. The iron is chemically diverse, ranging from simple iron oxides and salts to more complex organic chelates such as hydroxyphosphates in phytoferritin(1.

  9. Bioavailability & absorption of Iron and Anemia

    Directory of Open Access Journals (Sweden)

    Radhika Kapil

    2017-12-01

    Full Text Available Humans derive iron from their everyday diet, predominantly from plant foods and the rest from foods of animal origin. Iron is found in food as either haem or non-haem iron.  Haem iron, which is about up to 40 per cent of the iron in meat, poultry, and fish, is well absorbed.  All the iron in plants (fruits, vegetables, grains, nuts is in the form of non-haem iron and is relatively poorly absorbed. Non-haem iron contributes about 90-95 per cent of total daily iron in vegan diets. In western countries,the intake of haem iron from meat and meat products accounts for bulk of the dietary iron. The haem iron consumption is minimal in developing countries with majority obtaining non-haem iron from cereals, pulses, vegetables and fruits'. The diets is plagued by low iron content and poor absorption. Major sources of non-haem iron are plant foods. The iron is chemically diverse, ranging from simple iron oxides and salts to more complex organic chelates such as hydroxyphosphates in phytoferritin(1.

  10. Assessment of reduction in perception of nuclear risk related to perception of environmental risk

    International Nuclear Information System (INIS)

    Boemer, Veronica Araujo; Aquino, Afonso Rodrigues de

    2009-01-01

    This work presents a bibliographic research accomplished to evaluate the matter of reduction in risk perception, on people in general, that nuclear energy can show, for generation of electric power, face to perception of risk associated to environmental questions, as the global warming, from greenhouse effect, addressing the matter to the relevance of public acceptance for the development of new technologies. (author)

  11. Reaction-Based Reactive Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center, Subproject to Co-PI Eric E. Roden. Final Report

    International Nuclear Information System (INIS)

    Roden, Eric E.

    2011-01-01

    This report summarizes research conducted in conjunction with a project entitled 'Reaction-Based Reactive Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center', which was funded through the Integrative Studies Element of the former NABIR Program (now the Environmental Remediation Sciences Program) within the Office of Biological and Environmental Research. Dr. William Burgos (The Pennsylvania State University) was the overall PI/PD for the project, which included Brian Dempsey (Penn State), Gour-Tsyh (George) Yeh (Central Florida University), and Eric Roden (formerly at The University of Alabama, now at the University of Wisconsin) as separately-funded co-PIs. The project focused on development of a mechanistic understanding and quantitative models of coupled Fe(III)/U(VI) reduction in FRC Area 2 sediments. The work builds on our previous studies of microbial Fe(III) and U(VI) reduction, and was directly aligned with the Scheibe et al. ORNL FRC Field Project at Area 2.

  12. Relations between finite zero structure of the plant and the standard $H_\\infty$ controller order reduction

    NARCIS (Netherlands)

    Watanabe, Takao; Stoorvogel, Antonie Arij

    2001-01-01

    A relation between the finite zero structure of the plant and the standard $H_\\infty$ controller was studied. The mechanism was also investigated using the ARE-based $H_\\infty$ controller that is represented by a free parameter. It was observed that the mechanism of the controller reduction is

  13. Rethinking Iron Regulation and Assessment in Iron Deficiency, Anemia of Chronic Disease, and Obesity: Introducing Hepcidin

    Science.gov (United States)

    Tussing-Humphreys, Lisa; Pustacioglu, Cenk; Nemeth, Elizabeta; Braunschweig, Carol

    2012-01-01

    Adequate iron availability is essential to human development and overall health. Iron is a key component of oxygen-carrying proteins, has a pivotal role in cellular metabolism, and is essential to cell growth and differentiation. Inadequate dietary iron intake, chronic and acute inflammatory conditions, and obesity are each associated with alterations in iron homeostasis. Tight regulation of iron is necessary because iron is highly toxic and human beings can only excrete small amounts through sweat, skin and enterocyte sloughing, and fecal and menstrual blood loss. Hepcidin, a small peptide hormone produced mainly by the liver, acts as the key regulator of systemic iron homeostasis. Hepcidin controls movement of iron into plasma by regulating the activity of the sole known iron exporter ferroportin-1. Downregulation of the ferroportin-1 exporter results in sequestration of iron within intestinal enterocytes, hepatocytes, and iron-storing macrophages reducing iron bioavailability. Hepcidin expression is increased by higher body iron levels and inflammation and decreased by anemia and hypoxia. Importantly, existing data illustrate that hepcidin may play a significant role in the development of several iron-related disorders, including the anemia of chronic disease and the iron dysregulation observed in obesity. Therefore, the purpose of this article is to discuss iron regulation, with specific emphasis on systemic regulation by hepcidin, and examine the role of hepcidin within several disease states, including iron deficiency, anemia of chronic disease, and obesity. The relationship between obesity and iron depletion and the clinical assessment of iron status will also be reviewed. PMID:22717199

  14. Food Reduction in Avicenna’s View and Related Principles in Classical Medicine

    Science.gov (United States)

    Nozad, Aisan; Naseri, Mohsen; Safari, Mir Bahram; Abd Al Ahadi, Azam; Ghaffari, Farzaneh

    2016-01-01

    Context Traditional Iranian medicine (TIM) is a rich and valuable school of thought that believes medications are not the only effective approach for the treatment of diseases but that nutrition is also important. Evidence Acquisition Our study includes two parts; the first is a book review of the Canon of Medicine by Avicenna (10th and 11th centuries), in which we focus on finding and understanding Avicenna’s point of view. In the second part, we searched for “food reduction” as a key word from 2000 to 2015 in databases such as Google Scholar, PubMed, Copernicus, DOAJ, EBSCO-CINAHL, and the Iranian search database Iranmedex for principles of food reduction in classical medicine. Results The main methods of treatment in traditional medicine include changes in lifestyle, especially diet, the use of medications, and the use of manipulation methods. For diet, the individual may be prohibited from eating or food amounts may be decreased or increased. Centuries ago, Avicenna was making use of methods of food reduction as an important therapeutic approach in the treatment of diseases. According to him, food reduction, to the extent that it does not cause energy loss helps to cure disease. Avicenna has proposed food reduction as an aid to treating a variety of ailments such as headaches and reflux. Conclusions Today, a variety of basic and clinical research has shown that food reduction or calorie restriction to a standard level can effectively prevent and treat a variety of diseases such as neoplasms, diabetes, and kidney disease. Practical principles explained by traditional Iranian medicine, in particular Avicenna, could open important and quite uncomplicated strategies for the prevention and treatment of diseases. PMID:27621927

  15. Heterojunction nanowires having high activity and stability for the reduction of oxygen: Formation by self-assembly of iron phthalocyanine with single walled carbon nanotubes (FePc/SWNTs)

    KAUST Repository

    Zhu, Jia

    2014-04-01

    A self-assembly approach to preparing iron phthalocyanine/single-walled carbon nanotube (FePc/SWNT) heterojunction nanowires as a new oxygen reduction reaction (ORR) electrocatalyst has been developed by virtue of water-adjusted dispersing in 1-cyclohexyl-pyrrolidone (CHP) of the two components. The FePc/SWNT nanowires have a higher Fermi level compared to pure FePc (d-band center, DFT. =. -0.69. eV versus -0.87. eV, respectively). Consequently, an efficient channel for transferring electron to the FePc surface is readily created, facilitating the interaction between FePc and oxygen, so enhancing the ORR kinetics. This heterojunction-determined activity in ORR illustrates a new stratagem to preparing non-noble ORR electrocatalysts of significant importance in constructing real-world fuel cells. © 2013 Elsevier Inc.

  16. PPARα, PPARγ and SREBP-1 pathways mediated waterborne iron (Fe)-induced reduction in hepatic lipid deposition of javelin goby Synechogobius hasta.

    Science.gov (United States)

    Chen, Guang-Hui; Luo, Zhi; Chen, Feng; Shi, Xi; Song, Yu-Feng; You, Wen-Jing; Liu, Xu

    2017-07-01

    The 42-day experiment was conducted to investigate the effects and mechanism of waterborne Fe exposure influencing hepatic lipid deposition in Synechogobius hasta. For that purpose, S. hasta were exposed to four Fe concentrations (0 (control), 0.36, 0.72 and 1.07μM Fe) for 42days. On days 21 and 42, morphological parameters, hepatic lipid deposition and Fe contents, and activities and mRNA levels of enzymes and genes related to lipid metabolism, including lipogenic enzymes (6PGD, G6PD, ME, ICDH, FAS and ACC) and lipolytic enzymes (CPTI, HSL), were analyzed. With the increase of Fe concentration, hepatic Fe content tended to increase but HSI and lipid content tended to decrease. On day 21, Fe exposure down-regulated the lipogenic activities of 6PGD, G6PD, ICDH and FAS as well as the mRNA levels of G6PD, ACCa, FAS, SREBP-1 and PPARγ, but up-regulated CPT I, HSLa and PPARα mRNA levels. On day 42, Fe exposure down-regulated the lipogenic activities of 6PGD, G6PD, ICDH and FAS as well as the mRNA levels of 6PGD, ACCa, FAS and SREBP-1, but up-regulated CPT I, HSLa, PPARα and PPARγ mRNA levels. Using primary S. hasta hepatocytes, specific pathway inhibitors (GW6471 for PPARα and fatostatin for SREBP-1) and activator (troglitazone for PPARγ) were used to explore the signaling pathways of Fe reducing lipid deposition. The GW6471 attenuated the Fe-induced down-regulation of mRNA levels of 6PGD, G6PD, ME, FAS and ACCa, and attenuated the Fe-induced up-regulation of mRNA levels of CPT I, HSLa and PPARα. Compared with single Fe-incubated group, the mRNA levels of G6PD, ME, FAS, ACCa, ACCb and PPARγ were up-regulated while the CPT I mRNA levels were down-regulated after troglitazone pre-treatment; fatostatin pre-treatment down-regulated the mRNA levels of 6PGD, ME, FAS, ACCa, ACCb and SREBP-1, and increased the CPT I and HSLa mRNA levels. Based on these results above, our study indicated that Fe exposure reduced hepatic lipid deposition by down-regulating lipogenesis

  17. Iron Supply Affects Anthocyanin Content and Related Gene Expression in Berries of Vitis vinifera cv. Cabernet Sauvignon.

    Science.gov (United States)

    Shi, Pengbao; Li, Bing; Chen, Haiju; Song, Changzheng; Meng, Jiangfei; Xi, Zhumei; Zhang, Zhenwen

    2017-02-14

    Anthocyanins are important compounds for red grape and red wine quality, and can be influenced by supply of nutrients such as nitrogen, phosphorus, potassium, zinc, and iron. The present work aims to gain a better understanding of the effect of iron supply on anthocyanins concentration in grape berries. To this end, own-rooted four-year-old Cabernet Sauvignon grapevines ( Vitis vinifera ) were fertigated every three days with 0, 23, 46, 92, and 184 μM iron (Fe) from ferric ethylenediamine di ( o -hydroxyphenylacetic) acid (Fe-EDDHA) in a complete nutrient solution. Fe deficiency or excess generally led to higher concentrations of titratable acidity and skin/berry ratio, and to lower reducing sugar content, sugar/acid ratio, pH, berry weight, and concentration of anthocyanins. Most of the individual anthocyanins detected in this study, except cyanidin-3- O -glucoside, delphinidin-3- O -glucoside, and cyanidin-3- O -(6- O -coumaryl)-glucoside, in moderate Fe treatment (46 μM) grapes were significantly higher than those of other treatments. Genes encoding chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), leucoanthocyanidin dioxygenase (LDOX), and anthocyanin O -methyltransferase (AOMT) exhibited higher transcript levels in berries from plants cultivated with 46 μM Fe compared to the ones cultivated with other Fe concentrations. We suggest that grape sugar content, anthocyanins content, and transcriptions of genes involved in anthocyanin biosynthesis were correlated with Fe supply concentrations.

  18. Iron Supply Affects Anthocyanin Content and Related Gene Expression in Berries of Vitis vinifera cv. Cabernet Sauvignon

    Directory of Open Access Journals (Sweden)

    Pengbao Shi

    2017-02-01

    Full Text Available Anthocyanins are important compounds for red grape and red wine quality, and can be influenced by supply of nutrients such as nitrogen, phosphorus, potassium, zinc, and iron. The present work aims to gain a better understanding of the effect of iron supply on anthocyanins concentration in grape berries. To this end, own-rooted four-year-old Cabernet Sauvignon grapevines (Vitis vinifera were fertigated every three days with 0, 23, 46, 92, and 184 μM iron (Fe from ferric ethylenediamine di (o-hydroxyphenylacetic acid (Fe-EDDHA in a complete nutrient solution. Fe deficiency or excess generally led to higher concentrations of titratable acidity and skin/berry ratio, and to lower reducing sugar content, sugar/acid ratio, pH, berry weight, and concentration of anthocyanins. Most of the individual anthocyanins detected in this study, except cyanidin-3-O-glucoside, delphinidin-3-O-glucoside, and cyanidin-3-O-(6-O-coumaryl-glucoside, in moderate Fe treatment (46 μM grapes were significantly higher than those of other treatments. Genes encoding chalcone isomerase (CHI, flavanone 3-hydroxylase (F3H, leucoanthocyanidin dioxygenase (LDOX, and anthocyanin O-methyltransferase (AOMT exhibited higher transcript levels in berries from plants cultivated with 46 μM Fe compared to the ones cultivated with other Fe concentrations. We suggest that grape sugar content, anthocyanins content, and transcriptions of genes involved in anthocyanin biosynthesis were correlated with Fe supply concentrations.

  19. Evaluation of physical health and its relation with history of work accidents in workers of the Central Iron Ore Company of Iran

    Directory of Open Access Journals (Sweden)

    Gholam Hossein Halvani

    2013-01-01

    Full Text Available Aims: This study was conducted to determine the state of physical symptoms of the Iranian Central Iron Ore Company workers and its relation with history of work accidents. Materials and Methods: This cross-sectional descriptive study was performed at the Iranian Central Iron Ore Company and included 388 workers sampled randomly out of 2100 workers. Research tool was a two-part questionnaire that its reliability was determined by some of researchers. Data was analyzed by SPSS (Statistical Package for Social Science software and statistical tests included variance analysis and Pearson′ correlation tests. Results: According to the findings, 80.9% had favorable physical health conditions and there was a significant relationship between physical health condition, history of work accidents, cigarette smoking and type of work. Conclusion: Considering the strong relationship between physical health and history of work accidents, it is proposed that high-level managers of the Central Iron Ore Company of Iran should pay special attention to the improvement of physical health, psychological, social, and welfare levels.

  20. Enhanced abiotic and biotic contributions to dechlorination of pentachlorophenol during Fe(III) reduction by an iron-reducing bacterium Clostridium beijerinckii Z

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yan [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); He, Yan, E-mail: yhe2006@zju.edu.cn [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); Feng, Xiaoli [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); Liang, Luyi [Experiment Teaching Center for Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Xu, Jianming, E-mail: jmxu@zju.edu.cn [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); Brookes, Philip C.; Wu, Jianjun [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China)

    2014-03-01

    A novel Fe(III) reducing bacterium, Clostridium beijerinckii Z, was isolated from glucose amended paddy slurries, and shown to dechlorinate pentachlorophenol (PCP). Fifty percent of added PCP was removed by C. beijerinckii Z alone, which increased to 83% in the presence of both C. beijerinckii Z and ferrihydrite after 11 days of incubation. Without C. beijerinckii Z, the surface-bound Fe(II) also abiotically dechlorinated more than 40% of the added PCP. This indicated that the biotic dechlorination by C. beijerinckii Z is a dominant process causing PCP transformation through anaerobic dechlorination, and that the dechlorination rates can be accelerated by simultaneous reduction of Fe(III). A biochemical electron transfer coupling process between sorbed Fe(II) produced by C. beijerinckii Z and reductive dehalogenation is a possible mechanism. This finding increases our knowledge of the role of Fe(III) reducing genera of Clostridium in dechlorinating halogenated organic pollutants, such as PCP, in anaerobic paddy soils. - Highlights: • A novel Fe(III) reducing bacterium Clostridium beijerinckii Z was isolated and could dechlorinate pentachlorophenol. • Anaerobic transformation of PCP by C. beijerinckii Z could be accelerated by simultaneous reduction of Fe(III). • Biochemical electron transfer coupling between Fe redox cycling and reductive dechlorination was the mechanism involved. • The finding increases our knowledge of Clostridium sp. regarding their multiple functions for dechlorinating pollutants.

  1. Enhanced abiotic and biotic contributions to dechlorination of pentachlorophenol during Fe(III) reduction by an iron-reducing bacterium Clostridium beijerinckii Z

    International Nuclear Information System (INIS)

    Xu, Yan; He, Yan; Feng, Xiaoli; Liang, Luyi; Xu, Jianming; Brookes, Philip C.; Wu, Jianjun

    2014-01-01

    A novel Fe(III) reducing bacterium, Clostridium beijerinckii Z, was isolated from glucose amended paddy slurries, and shown to dechlorinate pentachlorophenol (PCP). Fifty percent of added PCP was removed by C. beijerinckii Z alone, which increased to 83% in the presence of both C. beijerinckii Z and ferrihydrite after 11 days of incubation. Without C. beijerinckii Z, the surface-bound Fe(II) also abiotically dechlorinated more than 40% of the added PCP. This indicated that the biotic dechlorination by C. beijerinckii Z is a dominant process causing PCP transformation through anaerobic dechlorination, and that the dechlorination rates can be accelerated by simultaneous reduction of Fe(III). A biochemical electron transfer coupling process between sorbed Fe(II) produced by C. beijerinckii Z and reductive dehalogenation is a possible mechanism. This finding increases our knowledge of the role of Fe(III) reducing genera of Clostridium in dechlorinating halogenated organic pollutants, such as PCP, in anaerobic paddy soils. - Highlights: • A novel Fe(III) reducing bacterium Clostridium beijerinckii Z was isolated and could dechlorinate pentachlorophenol. • Anaerobic transformation of PCP by C. beijerinckii Z could be accelerated by simultaneous reduction of Fe(III). • Biochemical electron transfer coupling between Fe redox cycling and reductive dechlorination was the mechanism involved. • The finding increases our knowledge of Clostridium sp. regarding their multiple functions for dechlorinating pollutants

  2. Is the effect of silicon on rice uptake of arsenate (AsV) related to internal silicon concentrations, iron plaque and phosphate nutrition?

    International Nuclear Information System (INIS)

    Guo, W.; Zhu, Y.-G.; Liu, W.-J.; Liang, Y.-C.; Geng, C.-N.; Wang, S.-G.

    2007-01-01

    Solution culture experiments were conducted to investigate the effects of silicon (Si) on arsenate (As V ) uptake by rice. The addition of Si to the pretreatment or uptake solution significantly decreased shoot and root As concentrations (P < 0.001 and P < 0.05). The presence of Si in the pretreatment or uptake solution also significantly decreased shoot P concentrations (P < 0.001). The data demonstrated that both internal and external Si inhibited the uptake of As and P. Results of As uptake kinetics showed that the mechanism of the effect of Si on arsenate uptake is not caused by direct competition for active sites of transporters with As. The effect of Si on As uptake was not entirely mediated through the effect of Si on P uptake. Although the addition of Si to pretreatment solutions still significantly decreased shoot and root As concentrations, the extent of reduction became smaller when rice roots were coated with iron plaque. - Arsenate uptake by rice seedlings is affected by both Si (internal and external) and iron plaque on root surface

  3. Cast irons

    CERN Document Server

    1996-01-01

    Cast iron offers the design engineer a low-cost, high-strength material that can be easily melted and poured into a wide variety of useful, and sometimes complex, shapes. This latest handbook from ASM covers the entire spectrum of one of the most widely used and versatile of all engineered materials. The reader will find the basic, but vital, information on metallurgy, solidification characteristics, and properties. Extensive reviews are presented on the low-alloy gray, ductile, compacted graphite, and malleable irons. New and expanded material has been added covering high-alloy white irons used for abrasion resistance and high-alloy graphitic irons for heat and corrosion resistance. Also discussed are melting furnaces and foundry practices such as melting, inoculation, alloying, pouring, gating and rising, and molding. Heat treating practices including stress relieving, annealing, normalizing, hardening and tempering, autempering (of ductile irons), and surface-hardening treatments are covered, too. ASM Spec...

  4. Iron Therapy in Patients with Heart Failure and Iron Deficiency: Review of Iron Preparations for Practitioners.

    Science.gov (United States)

    Drozd, Marcin; Jankowska, Ewa A; Banasiak, Waldemar; Ponikowski, Piotr

    2017-06-01

    In patients with heart failure (HF), iron deficiency (ID) correlates with decreased exercise capacity and poor health-related quality of life, and predicts worse outcomes. Both absolute (depleted iron stores) and functional (where iron is unavailable for dedicated tissues) ID can be easily evaluated in patients with HF using standard laboratory tests (assessment of serum ferritin and transferrin saturation). Intravenous iron therapy in iron-deficient patients with HF and reduced ejection fraction has been shown to alleviate HF symptoms and improve exercise capacity and quality of life. In this paper, we provide information on how to diagnose ID in HF. Further we discuss pros and cons of different iron preparations and discuss the results of major trials implementing iron supplementation in HF patients, in order to provide practical guidance for clinicians on how to manage ID in patients with HF.

  5. Towards improved public awareness for climate related disaster risk reduction in South Africa: A Participatory Development Communication perspective

    Directory of Open Access Journals (Sweden)

    Tigere Chagutah

    2009-04-01

    Full Text Available Southern Africa has frequently been struck by damaging climate hazards which increasingly continue to threaten sustainable development efforts. Ominously, climate models predict that the incidence of major ‘wet’ events, such as floods and cyclones will increase in frequency against the background of a changing climate. Unfortunately, local mechanisms for communicating and raising public awareness of the consequent risks and appropriate risk reduction options remain weak. At the core of policy responses to the threat posed by climate related hazards, the South African government has adopted a disaster risk reduction approach to disaster management. This article details how, among many other measures to limit the adverse impacts of natural hazards, South Africa’s National Disaster Management Framework calls for the implementation of effective public awareness activities to increase the knowledge among communities of the risks they face and what risk-minimising actions they can take. Emphasis is laid on the importance of information provision and knowledge building among at-risk communities. Citing established theories and strategies, the author proposes a participatory development communication approach through Development Support Communication strategies for the provision of disaster risk reduction public awareness activities by government and other disaster risk reduction role-players in South Africa. By way of a review of completed studies and literature, the article provides guidance on the planning and execution of successful public communication campaigns and also discusses the constraints of communication campaigns as an intervention for comprehensive disaster risk reduction.

  6. Mitochondrial Iron Transport and Homeostasis in Plants

    Directory of Open Access Journals (Sweden)

    Anshika eJain

    2013-09-01

    Full Text Available Iron (Fe is an essential nutrient for plants and although the mechanisms controlling iron uptake from the soil are relatively well understood, comparatively little is known about subcellular trafficking of iron in plant cells. Mitochondria represent a significant iron sink within cells, as iron is required for the proper functioning of respiratory chain protein complexes. Mitochondria are a site of Fe-S cluster synthesis, and possibly heme synthesis as well. Here we review recent insights into the molecular mechanisms controlling mitochondrial iron transport and homeostasis. We focus on the recent identification of a mitochondrial iron uptake transporter in rice and a possible role for metalloreductases in iron uptake by mitochondria. In addition, we highlight recent advances in mitochondrial iron homeostasis with an emphasis on the roles of frataxin and ferritin in iron trafficking and storage within mitochondria.

  7. IRON-TOLERANT CYANOBACTERIA: IMPLICATIONS FOR ASTROBIOLOGY

    Science.gov (United States)

    Brown, Igor I.; Allen, Carlton C.; Mummey, Daniel L.; Sarkisova, Svetlana A.; McKay, David S.

    2006-01-01

    The review is dedicated to the new group of extremophiles - iron tolerant cyanobacteria. The authors have analyzed earlier published articles about the ecology of iron tolerant cyanobacteria and their diversity. It was concluded that contemporary iron depositing hot springs might be considered as relative analogs of Precambrian environment. The authors have concluded that the diversity of iron-tolerant cyanobacteria is understudied. The authors also analyzed published data about the physiological peculiarities of iron tolerant cyanobacteria. They made the conclusion that iron tolerant cyanobacteria may oxidize reduced iron through the photosystem of cyanobacteria. The involvement of both Reaction Centers 1 and 2 is also discussed. The conclusion that iron tolerant protocyanobacteria could be involved in banded iron formations generation is also proposed. The possible mechanism of the transition from an oxygenic photosynthesis to an oxygenic one is also discussed. In the final part of the review the authors consider the possible implications of iron tolerant cyanobacteria for astrobiology.

  8. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... risk for iron-deficiency anemia, including: Vegetarian or vegan eating patterns. Not eating enough iron-rich foods, ... iron-fortified foods that have iron added. Vegetarian diets can provide enough iron if you choose nonmeat ...

  9. 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