Sample records for magnitogorsk integrated iron

  1. Coke oven gas treatment and by-product plant of Magnitogorsk Integrated Iron and Steel Works

    SciTech Connect

    Egorov, V.N.; Anikin, G.J. [Magnitogorsk Integrated Iron and Steel Works, (Russian Federation); Gross, M. [Krupp Koppers GmbH, Essen (Germany)

    1995-12-01

    Magnitogorsk Integrated Iron and Steel Works, Russia, decided to erect a new coke oven gas treatment and by-product plant to replace the existing obsolete units and to improve the environmental conditions of the area. The paper deals with the technological concept and the design requirements. Commissioning is scheduled at the beginning of 1996. The paper describes H{sub 2}S and NH{sub 3} removal, sulfur recovery and ammonia destruction, primary gas cooling and electrostatic tar precipitation, and the distributed control system that will be installed.

  2. Experience in the adoption of a biochemical plant for treatment of phenol-containing wastewater. [Magnitogorsk Integrated Iron and Steel Works-USSR

    SciTech Connect

    Nedoseikin, V.A.; Prokof'ev, V.I.; Lysenko, N.D.

    1981-01-01

    The biochemical plant with a capacity of 500 m/sup 3/ was developed for treatment of phenol containing waste water and tar liquors from the processing of coking chemical products as well as blast furnace and coke oven gas condensates from the Magnitogorsk gas systems. The commissioning of this plant permitted almost complete elimination of discharges of toxic substances into the air and water in this industrial region. Work is continuing on the technological regime of the plant. 1 table.

  3. Features of a technology for making steel in 180-ton arc furnaces in the electric steelmaking shop at the Magnitogorsk Metallurgical Combine

    Microsoft Academic Search

    V. F. D’yachenko; A. V. Sarychev; A. B. Velikii; O. A. Nikolaev; Yu. A. Ivin; A. Kh. Valiakhmetov

    2008-01-01

    This article presents the main specifications of arc furnaces that have been installed in the electric steelmaking shop at\\u000a the Magnitogorsk Metallurgical Combine. One feature of these furnaces is that they can be operated with the use of liquid\\u000a pig iron. Here’ the amount of pig iron in the charge can be as high as 40%. The use of liquid

  4. Utilization of secondary energy resources at Magnitogorsk Metallurgical Combine

    NASA Astrophysics Data System (ADS)

    Ermolaev, V. N.; Klyuvgant, V. I.

    1982-12-01

    Savings obtained by the use of secondary thermal and energy resources at Magnitogorsk Metallurgical Combine during the period of the 10th five year plan are reviewed. These savings were obtained by fuller utilization of these resources, e.g., fuel from the use of blast furnace and coke oven gases and steam from boiler utilizers and evaporative cooling systems. The savings achieved were substantial.

  5. [Factors of anxiety and autonomic tonus in senior preschool children from Magnitogorsk].

    PubMed

    Ingel', F I; Stepanova, A A; Stepanova, O P; Legostaeva, T B; Koganova, Z I; Kozlova, O B

    2013-01-01

    In the paper there are presented the results of a study of anxiety and balance ofparts of autonomous nervous system in healthy children 5-7 years old, residing in different parts of Magnitogorsk. It is shown that state of heightened and high alert was shown to be more common among children living on the left bank of the Urals river around the Magnitogorsk Metallurgical Integrated Plant. In these children an imbalance in the work of the parts of the autonomic nervous system was detected more frequently, at that shifts were observed mainly in the direction to ergotropic tone. At the same time balanced work of the parts of the autonomic nervous system was observed more frequently in children living on the right bank of the Urals river. Discovered psychosomatic features of examined children turned out to be associated with both the social characteristics of family lifestyle and the emotional stress of parents, and the contents of some organic compounds in total snow samples collected in the territories of kindergartens which they attended. One ofthe most significant results ofthe work we consider the detection of a correlation relationship between emotional stress of parents and activity of key enzymes in their children, reflecting the protective and adaptive reactions of the organism. On the basis of these and previously obtained data, we suggest that social and psychological factors of the family are not only a potential source of maladaptation of the child, but, probably, can have an impact on the stability and sensitivity of the genome of children. PMID:24340605

  6. A Linear Programming Model of Integrated Iron and Steel Production

    Microsoft Academic Search

    Tibor Fabian

    1958-01-01

    Integrated steel mills usually have a choice over the use of various materials and production processes. Different ores may be used in the production of iron; steel scrap and iron can be used in different proportions in the production of steel. The economical usage rate of all materials is a function of numerous variables, among which the market price of

  7. Ironing out the issues: integrated approaches to understanding iron homeostasis in plants.

    PubMed

    Samira, Rozalynne; Stallmann, Anna; Massenburg, Lynnicia N; Long, Terri A

    2013-09-01

    Plants initialize responses to environmental changes at all levels, from signaling to translation and beyond. Such is the case for fluctuations in the availability of iron (Fe), one of the most critical micronutrients for plants. The results of these responses are physiological and morphological changes that lead to increased iron uptake from the rhizosphere, and recycling and reallocation of Fe, which must be properly localized within specific cells and cellular compartment for use. The use of reductionist approaches, in combination with in vivo and in situ Fe localization tools, has been able to shed light on critical signaling molecules, transcriptional regulators, transporters and other proteins involved in Fe homeostasis. Recent advances in elemental distribution and speciation analysis now enable detection and measurement of Fe and other elements at resolutions never seen before. Moreover, increasing use of systems biology approaches provide a substantially broader perspective of how Fe availability affects processes at many levels. This review highlights the latest in vivo and in situ iron localization approaches and some of the recent advances in understanding mechanisms that control Fe translocation. A broad perspective of how Fe localization data might one day be integrated with large-scale data to create models for Fe homeostasis is presented. PMID:23849132

  8. Iron

    MedlinePLUS

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

  9. FUGITIVE EMISSIONS FROM INTEGRATED IRON AND STEEL PLANTS

    EPA Science Inventory

    The report gives results of an engineering investigation of fugitive (non-ducted) emissions in the iron and steel industry. Operations excluded from the study are coke ovens, basic oxygen furnace (BOF) charging, and blast furnace cast houses. Fugitive emission factors for iron an...

  10. Integrated process for thermal cracking of heavy oil and reduction of iron ores

    SciTech Connect

    Koizumi, K.; Miura, E.; Mori, K.; Nishida, R.

    1982-06-15

    Vacuum distillation residue oil having a conradson carbon value of 5 to 40% and a specific gravity of 0.9 to 1.10 is thermally cracked in the presence of iron ore particles in fluidized state in a thermal cracking reactor thereby to produce light oils and cracked gases and to form by-product carbon, which is caused to deposit on the iron ore particles, which are then transferred to and heated at 800 to 1200/sup 0/ C in a reducing furnace to be reduced in a solid state reaction, into sponge iron. Thus, heavy oil is thermally cracked and sponge iron is produced by an economical, integrated process.

  11. Iron

    MedlinePLUS

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

  12. Laser sintering of separated and uniformly distributed multiwall carbon nanotubes integrated iron nanocomposites

    NASA Astrophysics Data System (ADS)

    Lin, Dong; Richard Liu, C.; Cheng, Gary J.

    2014-03-01

    Uniform distribution of carbon nanotubes (CNTs) in metal matrix during additive manufacturing of nanocomposites is always a challenge since the CNTs tend to aggregate in the molten pool. In this study, Multiwall carbon nanotubes (MWNTs) were separated and distributed uniformly into iron matrix by laser sintering process. MWNTs and iron powders were mixed together by magnetic stir, coated on steel 4140 surface, followed by laser sintering. Due to the fast heating and cooling rate, the CNTs are evenly distributed in the metal matrix. The temperature field was calculated by multiphysics simulation considering size effects, including size dependent melting temperature, thermal conductivity, and heat capacity. The SEM, TEM, and XRD were used to understand the laser sintering of CNT integrated nanocomposites. The results proved the feasibility of this technique to synthesize MWNTS integrated metal matrix nanocomposites.

  13. Probing Iron Accumulation in Sacchromyces cerevisiae Using Integrative Biophysical and Biochemical Techniques 

    E-print Network

    Miao, Ren

    2012-02-14

    iron regulation and its disruption leads to impaired iron regulation and iron accumulation within mitochondria. The iron accumulation resulted from impaired Fe/S cluster assembly in the eukaryotic model organism Saccharomyces cerevisiae (baker’s yeast...

  14. Chemical constituents in particulate emissions from an integrated iron and steel facility.

    PubMed

    Tsai, Jiun-Horng; Lin, Kuo-Hsiung; Chen, Chih-Yu; Ding, Jian-Yuan; Choa, Ching-Guan; Chiang, Hung-Lung

    2007-08-17

    Particle emissions from four integrated iron and steel plant processes, i.e., coke making, sintering, cold forming, and hot forming, were investigated in this study. Particle compositions of 21 element species, 11 ionic species, elemental carbon (EC), organic carbon (OC) and 16 polyaromatic hydrocarbons (PAHs) were analyzed to create "fingerprints" of the particles emitted from various processes in an integrated iron and steel plant. Results indicated that element compositions (0.11-0.42 g/g), water-soluble ions (0.34-0.52 g/g), elemental carbon (0.008-0.14 g/g), organic carbon (0.02-0.06 g/g) and PAHs (0.52-6.2 mg/g) contributed to the particle mass. In general, sulfur had a higher mass contribution than the other elements, which resulted from the use of coal, flux, heavy oil, and many recycled materials in the iron and steel plant. The particle mass contribution of potassium and chlorine in the sinter plant was higher than in other processes; this may be attributed to the lower boiling point and volatility of potassium. In addition, many recycled materials were fed into the sinter plant, causing a high concentration of potassium and chlorine in the particle phase. Eight PAH compounds were analyzed in the four processes. The carcinogenic compound Benzo(a)pyrene (BaP) was detectable only in the sintering process. PMID:17276592

  15. Integrated Chemical Systems: The Simultaneous Formation of Hybrid Nanocomposites of Iron Oxide and Organo Silsesquioxanes

    SciTech Connect

    Zhao, L; Clapsaddle, B; Jr., J S; Schaefer, D; Shea, K

    2004-10-15

    A sol-gel approach for the synthesis of hybrid nanocomposites of iron oxide and bridged polysilsesquioxanes has been established. The procedures allow for the simultaneous formation of iron oxide and polysilsesquioxane networks in monolithic xerogels and aerogels. These hybrid nanocomposites are synthesized from FeCl{sub 3} {center_dot} 6H{sub 2}O and functionalized silsesquioxane monomers in a one-pot reaction using epoxides as a gelation agent. The porosity and microstructure of the materials has been determined by nitrogen porosimetry, electron microscopy and ultra small angle X-ray scattering (USAXS). The hybrid nanocomposites exhibit a uniform dispersion of both components with no evidence for phase separation at length scales > 5 nm. At this limit of resolution it is not possible to distinguish between two independent interpenetrating networks integrated at molecular length scales or a random copolymer or mixtures of both.

  16. Superparamagnetic iron oxide nanoparticles impair endothelial integrity and inhibit nitric oxide production.

    PubMed

    Astanina, Ksenia; Simon, Yvette; Cavelius, Christian; Petry, Sandra; Kraegeloh, Annette; Kiemer, Alexandra K

    2014-11-01

    Superparamagnetic iron oxide nanoparticles (SPION) are widely used both clinically and experimentally for diverse in vivo applications, such as contrast enhancement in magnetic resonance imaging, hyperthermia and drug delivery. Biomedical applications require particles to have defined physical and chemical properties, and to be stable in biological media. Despite a suggested low cytotoxic action, adverse reactions of SPION in concentrations relevant for biomedical use have not yet been studied in sufficient detail. In the present work we employed Endorem®, dextran-stabilized SPION approved as an intravenous contrast agent, and compared its action to a set of other nanoparticles with potential for magnetic resonance imaging applications. SPION in concentrations relevant for in vivo applications were rapidly taken up by endothelial cells and exhibited no direct cytotoxicity. Electric cell impedance sensing measurements demonstrated that SPION, but not BaSO4/Gd nanoparticles, impaired endothelial integrity, as was confirmed by increased intercellular gap formation in endothelial monolayers. These structural changes induced the subcellular translocation and inhibition of the cytoprotective and anti-atherosclerotic enzyme endothelial NO-synthase and reduced NO production. Lipopolysaccharide-induced inflammatory NO production of macrophages was not affected by SPION. In conclusion, our data suggest that SPION might substantially alter endothelial integrity and function at therapeutically relevant doses, which are not cytotoxic. PMID:25123083

  17. Volatile organic compound constituents from an integrated iron and steel facility.

    PubMed

    Tsai, Jiun-Horng; Lin, Kuo-Hsiung; Chen, Chih-Yu; Lai, Nina; Ma, Sen-Yi; Chiang, Hung-Lung

    2008-09-15

    This study measured the volatile organic compound (VOC) constituents of four processes in an integrated iron and steel industry; cokemaking, sintering, hot forming, and cold forming. Toluene, 1,2,4-trimethylbenzene, isopentane, m,p-xylene, 1-butene, ethylbenzene, and benzene were the predominant VOC species in these processes. However, some of the chlorinated compounds were high (hundreds ppbv), i.e., trichloroethylene in all four processes, carbon tetrachloride in the hot forming process, chlorobenzene in the cold forming process, and bromomethane in the sintering process. In the sintering process, the emission factors of toluene, benzene, xylene, isopentane, 1,2,4-trimethylbenzene, and ethylbenzene were over 9 g/tonne-product. In the vicinity of the manufacturing plant, toluene, isopentane, 1,2,4-trimethylbenzene, xylene and ethylbenzene were high. Toluene, 1,2,4-trimethylbenzene, xylene, 1-butene and isopentane were the major ozone formation species. Aromatic compounds were the predominant VOC groups, constituting 45-70% of the VOC concentration and contributing >70% to the high ozone formation potential in the stack exhaust and workplace air. The sequence of VOC concentration and ozone formation potential was as follows: cold forming>sintering>hot forming>cokemaking. For the workplace air, cokemaking was the highest producer, which was attributed to the fugitive emissions of the coke oven and working process release. PMID:18289777

  18. Probing Iron Accumulation in Sacchromyces cerevisiae Using Integrative Biophysical and Biochemical Techniques

    E-print Network

    Miao, Ren

    2012-02-14

    Iron is an essential element for life. It is involved in a number of biological processes, including iron sulfur (Fe/S) cluster assembly and heme biosynthesis. However it is also potentially toxic due to its ability to induce formation of reactive...

  19. Fracture toughness studies of nodular iron using a J-integral approach

    E-print Network

    Mead, Hearl Edward

    1979-01-01

    in silicon content and nodule count except at low temperatures. An unsuccessful attempt was made to correlate the Kl lc values of nodular iron to the results of notched tensile tests. ACKNOWLEDGEMENT S The financial support of this work by the Iron... Electron Microscope Fractography RESULTS AND DISCUSSION Fracture Toughness Fractography Silicon Content Pearlite Content Xl. 16 18 20 21 21 21 30 33 35 35 42 71 Nodule Count Notched Tensile Tests Comparative Results CONCLUSIONS RE FE...

  20. Novel insights into iron metabolism by integrating deletome and transcriptome analysis in an iron deficiency model of the yeast Saccharomyces cerevisiae

    Microsoft Academic Search

    William J Jo; Jeung Hyoun Kim; Eric Oh; Daniel Jaramillo; Patricia Holman; Alex V Loguinov; Adam P Arkin; Corey Nislow; Guri Giaever; Chris D Vulpe

    2009-01-01

    BACKGROUND: Iron-deficiency anemia is the most prevalent form of anemia world-wide. The yeast Saccharomyces cerevisiae has been used as a model of cellular iron deficiency, in part because many of its cellular pathways are conserved. To better understand how cells respond to changes in iron availability, we profiled the yeast genome with a parallel analysis of homozygous deletion mutants to

  1. Machinability of Austempered Ductile Iron (ADI) Produced by Integrated Green Technology of Continuous Casting-Heat Treatment Processes

    NASA Astrophysics Data System (ADS)

    Meena, A.; El Mansori, M.; Ghidossi, P.

    2011-01-01

    This study presents the novel processing technique known as continuous casting-heat treatment processes to produce Austempered Ductile Iron (ADI) which is a new class of ductile iron. ADI is characterized by improved mechanical properties but has low machinability as compared to other cast irons and steel of similar strength. The novel technique is developed by the integration of casting (in die casting) and heat treatment processes in foundry to save cost energy and time. Specimens just after casting were austenitized at 930° C for 90 min and then austempered in fluidized bed at 380° C for 90 and 120 min. Hence, the effect of austempering time on the morphology of retained austenite and mechanical properties of the material were examined and compared with conventionally produced ADI. Drilling tests were then carried out to evaluate the machinability of ADI in terms of cutting forces, chip micro-hardness, chip morphology and surface roughness. The mechanical properties of ADI austempered for 120 min have found to be better as compare to the ADI austempered for 90 min.

  2. FIELD DEMONSTRATION OF EMERGING PIPE WALL INTEGRITY ASSESSMENT TECHNOLOGIES FOR LARGE CAST IRON WATER MAINS

    EPA Science Inventory

    The U.S. Environmental Protection Agency sponsored a large-scale field demonstration of innovative leak detection/location and condition assessment technologies on a 76-year old, 2,500-ft long, cement-lined, 24-in. cast iron water main in Louisville, KY from July through Septembe...

  3. Field Demonstration of Emerging Pipe Wall Integrity Assessment Technologies for Large Cast Iron Water Mains - Paper

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) sponsored a large-scale field demonstration of innovative leak detection/location and condition assessment technologies on a 76-year old, 2,000-ft long, cement-lined, 24-in. cast-iron water main in Louisville, KY from July through Se...

  4. Novel insights into iron metabolism by integrating deletome and transcriptome analysis in an iron deficiency model of the yeast Saccharomyces cerevisiae

    PubMed Central

    Jo, William J; Kim, Jeung Hyoun; Oh, Eric; Jaramillo, Daniel; Holman, Patricia; Loguinov, Alex V; Arkin, Adam P; Nislow, Corey; Giaever, Guri; Vulpe, Chris D

    2009-01-01

    Background Iron-deficiency anemia is the most prevalent form of anemia world-wide. The yeast Saccharomyces cerevisiae has been used as a model of cellular iron deficiency, in part because many of its cellular pathways are conserved. To better understand how cells respond to changes in iron availability, we profiled the yeast genome with a parallel analysis of homozygous deletion mutants to identify essential components and cellular processes required for optimal growth under iron-limited conditions. To complement this analysis, we compared those genes identified as important for fitness to those that were differentially-expressed in the same conditions. The resulting analysis provides a global perspective on the cellular processes involved in iron metabolism. Results Using functional profiling, we identified several genes known to be involved in high affinity iron uptake, in addition to novel genes that may play a role in iron metabolism. Our results provide support for the primary involvement in iron homeostasis of vacuolar and endosomal compartments, as well as vesicular transport to and from these compartments. We also observed an unexpected importance of the peroxisome for growth in iron-limited media. Although these components were essential for growth in low-iron conditions, most of them were not differentially-expressed. Genes with altered expression in iron deficiency were mainly associated with iron uptake and transport mechanisms, with little overlap with those that were functionally required. To better understand this relationship, we used expression-profiling of selected mutants that exhibited slow growth in iron-deficient conditions, and as a result, obtained additional insight into the roles of CTI6, DAP1, MRS4 and YHR045W in iron metabolism. Conclusion Comparison between functional and gene expression data in iron deficiency highlighted the complementary utility of these two approaches to identify important functional components. This should be taken into consideration when designing and analyzing data from these type of studies. We used this and other published data to develop a molecular interaction network of iron metabolism in yeast. PMID:19321002

  5. Lithium iron phosphate battery electrode integrity following high speed pulsed laser cutting

    NASA Astrophysics Data System (ADS)

    Lutey, Adrian H. A.; Fiorini, Maurizio; Fortunato, Alessandro; Carmignato, Simone

    2015-05-01

    Laser exposures are performed on lithium iron phosphate battery electrodes at with process parameters based on those leading to the smallest heat affected zone for low power laser exposure at . Scanning electron microscopy and Raman analysis are performed along the resulting cut edges to characterize macroscopic, chemical and microstructural changes resulting from laser exposure. The increase in velocity with respect to previous studies is found to limit macroscopic changes to areas directly exposed to the laser beam and greatly suppress or completely eliminate microstructural and chemical changes resulting from thermal conduction effects in the metallic conductor layers. These results confirm laser technology as a viable, more flexible solution to mechanical blanking devices for the cutting of lithium iron phosphate battery electrode films.

  6. Integration of magneto-optical active bismuth iron garnet on nongarnet substrates

    Microsoft Academic Search

    Timo Körner; Andreas Heinrich; Martin Weckerle; Patrick Roocks; Bernd Stritzker

    2008-01-01

    For optical communication, high quality magneto-optical active iron garnet films such as Y3Fe5O12 are important ceramic systems with extensive applications, e.g., as optical isolators [H. Dötsch et al., J. Opt. Soc. Am. B 22, 240 (2005)], optical modulators, etc. Thereby, garnets stand out due to their high Faraday rotation and low optical losses in the near infrared. Currently, it is

  7. Suppression of SLC11A2 Expression Is Essential to Maintain Duodenal Integrity During Dietary Iron Overload

    PubMed Central

    Shirase, Tomoyuki; Mori, Kiyoshi; Okazaki, Yasumasa; Itoh, Ken; Yamamoto, Masayuki; Tabuchi, Mitsuaki; Kishi, Fumio; Jiang, Li; Akatsuka, Shinya; Nakao, Kazuwa; Toyokuni, Shinya

    2010-01-01

    Iron is essential for the survival of mammals, but iron overload causes fibrosis and carcinogenesis. Reduced iron absorption and regulated release into circulation in duodenal mucosa constitute two major mechanisms of protection against dietary iron overload; however, their relative contribution remains elusive. To study the significance of the former process, we generated SLC11A2 transgenic mice (TGs) under the control of the chicken ?-actin promoter. TGs were viable and fertile, and displayed no overt abnormalities up to 20 months. No significant difference in iron concentration was observed in major solid organs between TGs and their wild-type littermates, suggesting that increased number of iron transporters does not lead to increased iron absorption. To test the sensitivity to iron overload, TGs and wild-type mice were fed with an iron-rich diet containing 2% ferric citrate. Iron supplementation caused suppression of endogenous duodenal SLC11A2 expression, down-regulation of duodenal ferroportin, and overexpression of hepatic hepcidin, precluding excessive iron uptake both in the TGs and wild-type mice. However, iron-treated TGs revealed increased mortality, resulting from oxidative mucosal damage leading to hemorrhagic erosion throughout the whole intestinal area. These findings suggest that reduced iron release from duodenal cells into circulation plays a role in mitigating excessive iron uptake from the diet and that finely regulated duodenal absorption is essential to protect intestinal mucosa from iron-induced oxidative damage. PMID:20558581

  8. Integration of nonlinear dielectric barium strontium titanate with polycrystalline yttrium iron garnet

    NASA Astrophysics Data System (ADS)

    Jia, Q. X.; Groves, J. R.; Arendt, P.; Fan, Y.; Findikoglu, A. T.; Foltyn, S. R.; Jiang, H.; Miranda, F. A.

    1999-03-01

    Biaxially oriented nonlinear dielectric Ba0.6Sr0.4TiO3 (BST) films have been grown on polycrystalline ferrite yttrium iron garnet (YIG) substrates. We use a structurally and chemically compatible MgO buffer to improve the crystallinity of the BST on polycrystalline YIG substrates, where the biaxially oriented MgO is deposited by an ion-beam assisted-deposition technique. The biaxially oriented BST has a dielectric loss of less than 0.01 and a capacitance tunability of greater than 25% at a direct current bias voltage of 40 V at room temperature.

  9. Fracture toughness studies of gray and ductile cast irons using a J-integral approach

    E-print Network

    Floyd, Donna Lynne Woodall

    1981-01-01

    , Atlanta, Georgia, Vov. 1977 26. "Recommended Procedure for JI Determination, " Ic as set up by ASTM-124 Committee, March 1977. 27. T. Lyman, Metals Handbook, 8th ed. , 1( 1961), pp. 349-365 and 379-394. 28. C. F. Walton, Gra and Ductile Iron Castin... function of distance (x) from the crack tip. Figure 2. Figure 3. Figure 4. K as a function of specimen c thickness (tl t2) Fracture toughness (KI ) as a Ic function of temperature (T) . . . Fracture toughness (KI ) as a Ic function of strain rate...

  10. Exploring Iron Metabolism and Regulation in Saccharomyces cerevisiae Using an Integrative Biophysical and Bioanalytical Approach 

    E-print Network

    Park, Jinkyu

    2013-12-03

    Fe metabolism in budding yeast Saccharomyces cerevisiae was studied using an integrative systems-level approach involving M?ssbauer, EPR, UV-Vis spectroscopy and LC-ICP-MS, combined with conventional biochemical techniques. Wild-type cells growing...

  11. Exploring Iron Metabolism and Regulation in Saccharomyces cerevisiae Using an Integrative Biophysical and Bioanalytical Approach

    E-print Network

    Park, Jinkyu

    2013-12-03

    Fe metabolism in budding yeast Saccharomyces cerevisiae was studied using an integrative systems-level approach involving M?ssbauer, EPR, UV-Vis spectroscopy and LC-ICP-MS, combined with conventional biochemical techniques. Wild-type cells growing...

  12. Integration of nonlinear dielectric barium strontium titanate with polycrystalline yttrium iron garnet

    SciTech Connect

    Jia, Q.X.; Groves, J.R.; Arendt, P.; Fan, Y.; Findikoglu, A.T.; Foltyn, S.R. [Superconductivity Technology Center, Mail Stop K763, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Superconductivity Technology Center, Mail Stop K763, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Jiang, H. [NZ Applied Technologies, 150-C New Boston Street, Woburn, Massachusetts 01801 (United States)] [NZ Applied Technologies, 150-C New Boston Street, Woburn, Massachusetts 01801 (United States); Miranda, F.A. [NASA Lewis Research Center, 21000 Brookpark Road, MS 54-5, Cleveland, Ohio 44135 (United States)] [NASA Lewis Research Center, 21000 Brookpark Road, MS 54-5, Cleveland, Ohio 44135 (United States)

    1999-03-01

    Biaxially oriented nonlinear dielectric Ba{sub 0.6}Sr{sub 0.4}TiO{sub 3} (BST) films have been grown on polycrystalline ferrite yttrium iron garnet (YIG) substrates. We use a structurally and chemically compatible MgO buffer to improve the crystallinity of the BST on polycrystalline YIG substrates, where the biaxially oriented MgO is deposited by an ion-beam assisted-deposition technique. The biaxially oriented BST has a dielectric loss of less than 0.01 and a capacitance tunability of greater than 25{percent} at a direct current bias voltage of 40 V at room temperature. {copyright} {ital 1999 American Institute of Physics.}

  13. Iron deficiency anemia

    PubMed Central

    Naigamwalla, Dinaz Z.; Webb, Jinelle A.; Giger, Urs

    2012-01-01

    Iron is essential to virtually all living organisms and is integral to multiple metabolic functions. The most important function is oxygen transport in hemoglobin. Iron deficiency anemia in dogs and cats is usually caused by chronic blood loss and can be discovered incidentally as animals may have adapted to the anemia. Severe iron deficiency is characterized by a microcytic, hypochromic, potentially severe anemia with a variable regenerative response. Iron metabolism and homeostasis will be reviewed, followed by a discussion of diagnostic testing and therapeutic recommendations for dogs and cats with iron deficiency anemia. PMID:22942439

  14. Iron-Air Rechargeable Battery

    NASA Technical Reports Server (NTRS)

    Narayan, Sri R. (Inventor); Prakash, G.K. Surya (Inventor); Kindler, Andrew (Inventor)

    2014-01-01

    Embodiments include an iron-air rechargeable battery having a composite electrode including an iron electrode and a hydrogen electrode integrated therewith. An air electrode is spaced from the iron electrode and an electrolyte is provided in contact with the air electrode and the iron electrodes. Various additives and catalysts are disclosed with respect to the iron electrode, air electrode, and electrolyte for increasing battery efficiency and cycle life.

  15. Health risk assessment of exposure to selected volatile organic compounds emitted from an integrated iron and steel plant.

    PubMed

    Chang, E-E; Wei-Chi, Wang; Li-Xuan, Zeng; Hung-Lung, Chiang

    2010-12-01

    Workplace air samples from sintering, cokemaking, and hot and cold forming processes in the integrated iron and steel industry were analyzed to determine their volatile organic compound (VOC) concentration. Sixteen VOC species including three paraffins (cyclohexane, n-hexane, methylcyclohexane), five chlorinated VOC species (trichloroethylene, 1,1,1-trichloroethane, tetrachloroethylene, chlorobenzene, 1,4-dichlorobenzene), and eight aromatics (benzene, ethylbenzene, styrene, toluene, m,p-xylene, o-xylene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene) were selected to measure their noncancer risk for workers. Concentrations of toluene, xylene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, dichlorobenzene, and trichloroethylene were high in all four processes. Carbon tetrachloride and tetrachloroethylene concentrations were high in the hot and cold forming processes. The noncancer risk followed the increasing order: cokemaking > sintering > hot forming > cold forming. 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene contributed 44% to 65% and 13% to 20% of noncancer risk, respectively, for the four processes. Benzene accounted for a high portion of the noncancer risk in cokemaking. The hazard index (HI: 17-108) of the average VOC concentrations suggests that health risks can be reduced by improving workplace air quality and protecting workers. PMID:20828338

  16. An integrated experimental and analytical approach to the chemical state imaging of iron in brain gliomas using X-ray absorption near edge structure spectroscopy

    Microsoft Academic Search

    Magdalena Szczerbowska-Boruchowska; Marek Lankosz; Mateusz Czyzycki; Dariusz Adamek

    2011-01-01

    X-ray absorption near-edge structure spectroscopy is used for human neoplastic tissues in order to investigate distributions and chemical states of iron. The specimens used in this study were obtained intraoperatively from brain gliomas of different types and various grades of malignancy and from a control subject. An integrated experimental and analytical approach toward topographic and quantitative analysis in thin freeze-dried

  17. Integrated analysis of the {open_quotes}sponge iron reactor and fuel cell system{close_quotes}

    SciTech Connect

    Lehrhofer, J.; Ghaemi, M.; Wernigg, H. [Graz Univ. of Technology (Austria)

    1996-12-31

    The system Sponge Iron Reactor/Fuel Cell (SIR/FC) is investigated from the ecological and technical aspects and also the pre-conversion energy chain as a part of the natural gas fuel cycle is analyzed. What are the decisive characteristics of a sponge iron reactor or the basic process cycle sponge iron/hydrogen/iron oxide? This process cycle offers a simple possibility to store the energy of synthesis gases in the form of sponge iron and at the same time to reform and condition these synthesis gases. As {open_quote}product{close_quote} of this energy storage one receives pure hydrogen which is intended for the running of fuel cells.

  18. Biofortification of wheat grain with iron and zinc: integrating novel genomic resources and knowledge from model crops

    PubMed Central

    Borrill, Philippa; Connorton, James M.; Balk, Janneke; Miller, Anthony J.; Sanders, Dale; Uauy, Cristobal

    2014-01-01

    Wheat, like many other staple cereals, contains low levels of the essential micronutrients iron and zinc. Up to two billion people worldwide suffer from iron and zinc deficiencies, particularly in regions with predominantly cereal-based diets. Although wheat flour is commonly fortified during processing, an attractive and more sustainable solution is biofortification, which requires developing new varieties of wheat with inherently higher iron and zinc content in their grains. Until now most studies aimed at increasing iron and zinc content in wheat grains have focused on discovering natural variation in progenitor or related species. However, recent developments in genomics and transformation have led to a step change in targeted research on wheat at a molecular level. We discuss promising approaches to improve iron and zinc content in wheat using knowledge gained in model grasses. We explore how the latest resources developed in wheat, including sequenced genomes and mutant populations, can be exploited for biofortification. We also highlight the key research and practical challenges that remain in improving iron and zinc content in wheat. PMID:24600464

  19. Integrated Self-Assembly of the Mms6 Magnetosome Protein to Form an Iron-Responsive Structure

    PubMed Central

    Feng, Shuren; Wang, Lijun; Palo, Pierre; Liu, Xunpei; Mallapragada, Surya K.; Nilsen-Hamilton, Marit

    2013-01-01

    A common feature of biomineralization proteins is their self-assembly to produce a surface consistent in size with the inorganic crystals that they produce. Mms6, a small protein of 60 amino acids from Magnetospirillum magneticum strain AMB-1 that promotes the in vitro growth of superparamagnetic magnetite nanocrystals, assembles in aqueous solution to form spherical micelles that could be visualized by TEM and AFM. The results reported here are consistent with the view that the N and C-terminal domains interact with each other within one polypeptide chain and across protein units in the assembly. From studies to determine the amino acid residues important for self-assembly, we identified the unique GL repeat in the N-terminal domain with additional contributions from amino acids in other positions, throughout the molecule. Analysis by CD spectroscopy identified a structural change in the iron-binding C-terminal domain in the presence of Fe3+. A change in the intrinsic fluorescence of tryptophan in the N-terminal domain showed that this structural change is transmitted through the protein. Thus, self-assembly of Mms6 involves an interlaced structure of intra- and inter-molecular interactions that results in a coordinated structural change in the protein assembly with iron binding. PMID:23857056

  20. Iron chelators and iron toxicity

    Microsoft Academic Search

    Gary M. Brittenham

    2003-01-01

    Iron chelation may offer new approaches to the treatment and prevention of alcoholic liver disease. With chronic excess, either iron or alcohol alone may individually injure the liver and other organs. In combination, each exaggerates the adverse effects of the other. In alcoholic liver disease, both iron and alcohol contribute to the production of hepatic fibrosis through their effects on

  1. Evaluation of effects of Ma??urabhasma on structural and functional integrity of small intestine in comparison with ferrous sulfate using an experimental model of iron deficiency anemia

    PubMed Central

    Gawde, Suchita Rajanikant; Patel, Tejal C.; Rege, Nirmala N.; Gajbhiye, Snehalata; Uchil, Dinesh

    2015-01-01

    Background: The present study was planned to assess effects of Ma??urabhasma (MB) on structural and functional integrity of small intestine using an animal model of iron deficiency anemia (IDA) in rat. Methods: IDA was induced by giving iron deficient diet and retro-orbital bloodletting for 21 days in Wistar female rats. Rats (n = 72) were divided into six groups: (i) Control group, (ii) IDA rats, (iii) IDA rats receiving vehicle, (iv) rats receiving ferrous sulfate (40 mg/kg), (vi) rats receiving a low dose (22.5 mg/kg) of MB, (vi) rats receiving a high dose (45 mg/kg) of MB. Treatment was conducted for a period of 21 days followed by an assessment of change in hemoglobin (Hb) levels, lactase levels, lipid peroxidation activity by measuring malondialdehyde (MDA) levels and jejunal morphometry. Results: In the present study, the lactase activity was markedly reduced in iron-deficient rats. Our study has demonstrated that intestinal morphology and MDA levels were not altered in the animals with IDA as compared to normal animals. In phase II, improvement in Hb response to ferrous sulfate was accompanied by an improvement in lactase activity. However, it significantly increased MDA levels with derangement of the normal villous structure. Rats receiving a low dose of MB did not have increased MDA levels. It did not alter the jejunal villous structure and improved lactase activity, but hematinic activity was found to be less than that of ferrous sulfate. Rats receiving a high dose of MB showed significantly improved Hb as well as lactase levels. They exhibited damage to the villous structure and increased MDA levels, but the effects were significantly less as compared to ferrous sulfate group. Conclusion: Rats receiving a high dose of MB have shown improvement in hematinic and lactase levels comparable to those receiving ferrous sulfate. However, it causes lesser oxidative damage as compared to ferrous sulfate. This is an encouraging finding because it indicates the potential of MB to cause lesser gastrointestinal side effects compared to ferrous sulfate. PMID:26120227

  2. [Iron deficiency in domestic animals].

    PubMed

    Agergaard, N; Rotenberg, S; Boisen, S

    1984-01-01

    Iron is essential for the organism. In ionized forms (Fe++, Fe ), it constitutes an integrated part of a lot of different functional proteins (Figure 1). The most important functions are participation in oxygen transport in blood, oxygen storage in muscle tissues and oxidation of nutrients in the mitochondria. Iron is an essential part of cytochrome C and alpha-glycerolphosphate dehydrogenase, and early stages of iron deficiency may, therefore, cause disturbances in tissue metabolism before development of anaemia. Thus, haemoglobin determinations is not very suitable for diagnosing early iron deficiency. The content of iron in roughages, apart from root crops (Table II), is usually sufficient to cover the requirement of domestic animals (Table III), which is met by about 50 mg per kg feed dry matter. Iron deficiency is very often caused by a reduced absorption in the intestinal tract because of components in the feed forming complexes with iron of very low solubility or inhibitors reducing the absorption processes. The immune status of the organism and its resistance against infections depends on the iron supply. Iron deficiency inhibits the myeloperoxidase activity and thus decreases the bacteriocide effect of the leucocytes. In spite of this, when exposed to infections the physiological mechanisms reduce the blood concentration of available iron. By this mode of action, invading pathogens, needing iron like the host animals, will be restrained. The low content of iron in milk (Table II) combined with a high content of iron binding lactoferrin, is ideal to protect newborn and milk fed young animals against intestinal infections.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6431395

  3. Microbial Iron Cycling in Acidic Geothermal Springs of Yellowstone National Park: Integrating Molecular Surveys, Geochemical Processes, and Isolation of Novel Fe-Active Microorganisms

    PubMed Central

    Kozubal, Mark A.; Macur, Richard E.; Jay, Zackary J.; Beam, Jacob P.; Malfatti, Stephanie A.; Tringe, Susannah G.; Kocar, Benjamin D.; Borch, Thomas; Inskeep, William P.

    2012-01-01

    Geochemical, molecular, and physiological analyses of microbial isolates were combined to study the geomicrobiology of acidic iron oxide mats in Yellowstone National Park. Nineteen sampling locations from 11 geothermal springs were studied ranging in temperature from 53 to 88°C and pH 2.4 to 3.6. All iron oxide mats exhibited high diversity of crenarchaeal sequences from the Sulfolobales, Thermoproteales, and Desulfurococcales. The predominant Sulfolobales sequences were highly similar to Metallosphaera yellowstonensis str. MK1, previously isolated from one of these sites. Other groups of archaea were consistently associated with different types of iron oxide mats, including undescribed members of the phyla Thaumarchaeota and Euryarchaeota. Bacterial sequences were dominated by relatives of Hydrogenobaculum spp. above 65–70°C, but increased in diversity below 60°C. Cultivation of relevant iron-oxidizing and iron-reducing microbial isolates included Sulfolobus str. MK3, Sulfobacillus str. MK2, Acidicaldus str. MK6, and a new candidate genus in the Sulfolobales referred to as Sulfolobales str. MK5. Strains MK3 and MK5 are capable of oxidizing ferrous iron autotrophically, while strain MK2 oxidizes iron mixotrophically. Similar rates of iron oxidation were measured for M. yellowstonensis str. MK1 and Sulfolobales str. MK5. Biomineralized phases of ferric iron varied among cultures and field sites, and included ferric oxyhydroxides, K-jarosite, goethite, hematite, and scorodite depending on geochemical conditions. Strains MK5 and MK6 are capable of reducing ferric iron under anaerobic conditions with complex carbon sources. The combination of geochemical and molecular data as well as physiological observations of isolates suggests that the community structure of acidic Fe mats is linked with Fe cycling across temperatures ranging from 53 to 88°C. PMID:22470372

  4. Bacterial iron homeostasis

    Microsoft Academic Search

    Simon C Andrews; Andrea K Robinson; Francisco Rodr??guez-Quiñones

    2003-01-01

    Iron is essential to virtually all organisms, but poses problems of toxicity and poor solubility. Bacteria have evolved various mechanisms to counter the problems imposed by their iron dependence, allowing them to achieve effective iron homeostasis under a range of iron regimes. Highly efficient iron acquisition systems are used to scavenge iron from the environment under iron-restricted conditions. In many

  5. Murine macrophages response to iron.

    PubMed

    Polati, Rita; Castagna, Annalisa; Bossi, Alessandra Maria; Alberio, Tiziana; De Domenico, Ivana; Kaplan, Jerry; Timperio, Anna Maria; Zolla, Lello; Gevi, Federica; D'Alessandro, Angelo; Brunch, Ryan; Olivieri, Oliviero; Girelli, Domenico

    2012-12-01

    Macrophages play a critical role at the crossroad between iron metabolism and immunity, being able to store and recycle iron derived from the phagocytosis of senescent erythrocytes. The way by which macrophages manage non-heme iron at physiological concentration is still not fully understood. We investigated protein changes in mouse bone marrow macrophages incubated with ferric ammonium citrate (FAC 10 ?M iron). Differentially expressed spots were identified by nano RP-HPLC-ESI-MS/MS. Transcriptomic, metabolomics and western immunoblotting analyses complemented the proteomic approach. Pattern analysis was also used for identifying networks of proteins involved in iron homeostasis. FAC treatment resulted in higher abundance of several proteins including ferritins, cytoskeleton related proteins, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) at the membrane level, vimentin, arginase, galectin-3 and macrophage migration inhibitory factor (MIF). Interestingly, GAPDH has been recently proposed to act as an alternative transferrin receptor for iron acquisition through internalization of the GAPDH-transferrin complex into the early endosomes. FAC treatment also induced the up-regulation of oxidative stress-related proteins (PRDX), which was further confirmed at the metabolic level (increase in GSSG, 8-isoprostane and pentose phosphate pathway intermediates) through mass spectrometry-based targeted metabolomics approaches. This study represents an example of the potential usefulness of "integarated omics" in the field of iron biology, especially for the elucidation of the molecular mechanisms controlling iron homeostasis in normal and disease conditions. This article is part of a Special Issue entitled: Integrated omics. PMID:22835775

  6. Iron and alloys of iron. [lunar resources

    NASA Technical Reports Server (NTRS)

    Sastri, Sankar

    1992-01-01

    All lunar soil contains iron in the metallic form, mostly as an iron-nickel alloy in concentrations of a few tenths of 1 percent. Some of this free iron can be easily separated by magnetic means. It is estimated that the magnetic separation of 100,000 tons of lunar soil would yield 150-200 tons of iron. Agglutinates contain metallic iron which could be extracted by melting and made into powder metallurgy products. The characteristics and potential uses of the pure-iron and iron-alloy lunar products are discussed. Processes for working iron that might be used in a nonterrestrial facility are also addressed.

  7. Integration of bulk-quality thin film magneto-optical cerium-doped yttrium iron garnet on silicon nitride photonic substrates.

    PubMed

    Onbasli, Mehmet C; Goto, Taichi; Sun, Xueyin; Huynh, Nathalie; Ross, C A

    2014-10-20

    Cerium substituted yttrium iron garnet (Ce:YIG) films were grown on yttrium iron garnet (YIG) seed layers on silicon nitride films using pulsed laser deposition. Optimal process conditions for forming garnet films on silicon nitride are presented. Bulk or near-bulk magnetic and magneto-optical properties were observed for 160 nm thick Ce:YIG films grown at 640 °C on rapid thermal annealed 40 nm thick YIG grown at 640 °C and 2 Hz pulse rate. The effect of growth temperature and deposition rate on structural, magnetic and magneto-optical properties has been investigated. PMID:25401550

  8. Iron and iron derived radicals

    SciTech Connect

    Borg, D.C.; Schaich, K.M.

    1987-04-01

    We have discussed some reactions of iron and iron-derived oxygen radicals that may be important in the production or treatment of tissue injury. Our conclusions challenge, to some extent, the usual lines of thought in this field of research. Insofar as they are born out by subsequent developments, the lessons they teach are two: Think fastexclamation Think smallexclamation In other words, think of the many fast reactions that can rapidly alter the production and fate of highly reactive intermediates, and when considering the impact of competitive reactions on such species, think how they affect the microenvironment (on the molecular scale) ''seen'' by each reactive molecule. 21 refs., 3 figs., 1 tab.

  9. Genetics Home Reference: Iron-refractory iron deficiency anemia

    MedlinePLUS

    ... Genetic disorder catalog Conditions > Iron-refractory iron deficiency anemia On this page: Description Genetic changes Inheritance Diagnosis ... July 2014 What is iron-refractory iron deficiency anemia? Iron-refractory iron deficiency anemia is one of ...

  10. Integration

    NSDL National Science Digital Library

    David Liao

    In this video, we become familiar with integrals, both by understanding them as sums of areas under plots of functions, and by understanding them as anti-derivatives. We present the u-substitution rule, which is the analog of the chain rule for differentiating composite functions.

  11. Pharmacology of Iron Transport

    PubMed Central

    Byrne, Shaina L.; Krishnamurthy, Divya; Wessling-Resnick, Marianne

    2013-01-01

    Elucidating the molecular basis for the regulation of iron uptake, storage, and distribution is necessary to understand iron homeostasis. Pharmacological tools are emerging to identify and distinguish among different iron transport pathways. Stimulatory or inhibitory small molecules with effects on iron uptake can help characterize the mechanistic elements of iron transport and the roles of the transporters involved in these processes. In particular, iron chelators can serve as potential pharmacological tools to alleviate diseases of iron overload. This review focuses on the pharmacology of iron transport, introducing iron transport membrane proteins and known inhibitors. PMID:23020294

  12. Iron and Prochlorococcus/

    E-print Network

    Thompson, Anne Williford

    2009-01-01

    Iron availability and primary productivity in the oceans are intricately linked through photosynthesis. At the global scale we understand how iron addition induces phytoplankton blooms through meso-scale iron-addition ...

  13. Iron deficiency anemia

    MedlinePLUS

    Anemia - iron deficiency ... Iron deficiency anemia is the most common form of anemia. Red blood cells bring oxygen to the ... such as your spleen, remove old blood cells. Iron is a key part of red blood cells. ...

  14. Alternative control techniques document: PM-10 emissions from selected processes at coke ovens and integrated iron and steel mills. Final report

    SciTech Connect

    Marsosudiro, P.J.; Snow, W.S.

    1994-02-01

    The purpose of the document is to provide guidance to state and local air quality management agencies for determining reasonably available control technologies (RACT) and best available control technologies (BACT) that apply to PM-10 sources in the iron and steel industry. Emission sources addressed are coke pushing, coke quenching, coke sizing and screening, casthouse operations, hot metal transfer, and desulfurization. These sources were selected for analysis because they are not presently regulated under New Source Performance Standards (NSPS). Emission control system descriptions, environmental and energy impact assessments, and control cost analyses are presented. The principal emission collection devices used are the fabric filter and wet venturi scrubber.

  15. Development of an integrated in-situ remediation technology. Draft topical report for Task {number_sign}3.3 entitled, ``Iron dechlorination studies`` (September 26, 1994--August 31, 1997)

    SciTech Connect

    Orth, R.; Dauda, T.; McKenzie, D.E.

    1997-11-01

    Contamination in low-permeability soils poses a significant technical challenge to in-situ remediation efforts. Poor accessibility to the contaminants and difficulty in delivery of treatment reagents have rendered existing in-situ treatments such as bioremediation, vapor extraction, and pump and treat rather ineffective when applied to low permeability soils present at many contaminated sites. The technology is an integrated in-situ treatment in which established geotechnical methods are used to install degradation zones directly in the contaminated soil and electro-osmosis is utilized to move the contaminants back and forth through those zones until the treatment is completed. The present Topical Report for Task {number_sign}3.3 summarizes the iron dechlorination research conducted by Monsanto Company.

  16. HEPCIDIN AND IRON HOMEOSTASIS

    PubMed Central

    Ganz, Tomas; Nemeth, Elizabeta

    2014-01-01

    Despite fluctuations in dietary iron intake and intermittent losses through bleeding, the plasma iron concentrations in humans remain stable at 10–30 ?M. While most of the iron entering blood plasma comes from recycling, appropriate amount of iron is absorbed from the diet to compensate for losses and maintain nontoxic amounts in stores. Plasma iron concentration and iron distribution are similarly regulated in laboratory rodents. The hepatic peptide hepcidin was identified as the systemic iron-regulatory hormone. In the efferent arc, hepcidin regulates intestinal iron absorption, plasma iron concentrations, and tissue iron distribution by inducing degradation of its receptor, the cellular iron exporter ferroportin. Ferroportin exports iron into plasma from absorptive enterocytes, from macrophages that recycle the iron of senescent erythrocytes, and from hepatocytes that store iron. In the more complex and less well understood afferent arc, hepatic hepcidin synthesis is transcriptionally regulated by extracellular and intracellular iron concentrations through a molecular complex of bone morphogenetic protein receptors and their iron-specific ligands, modulators and iron sensors. Through as yet undefined pathways, hepcidin is also homeostatically regulated by the iron requirements of erythroid precursors for hemoglobin synthesis. In accordance with the role of hepcidin-mediated iron redistribution in host defense, hepcidin production is regulated by inflammation as well. Increased hepcidin concentrations in plasma are pathogenic in iron-restrictive anemias including anemias associated with inflammation, chronic kidney disease and some cancers. Hepcidin deficiency causes iron overload in hereditary hemochromatosis and ineffective erythropoiesis. Hepcidin, ferroportin and their regulators represent potential targets for the diagnosis and treatment of iron disorders and anemias. PMID:22306005

  17. Integrated magnetic studies of the El Romeral iron-ore deposit, Chile: implications for ore genesis and modeling of magnetic anomalies

    NASA Astrophysics Data System (ADS)

    Alva-Valdivia, L. M.; Rivas-Sánchez, M. L.; Goguitchaichvili, A.; Urrutia-Fucugauchi, J.; Gonzalez, A.; Vivallo, W.

    2003-08-01

    Mineralogical and rock-magnetic studies of iron ores and host rocks in El Romeral Mine are carried out to characterize the magnetic mineralogy and the processes that affect the natural remanent magnetization during emplacement and evolution of the iron-ore deposit. Extremely important is the identification of magnetic mineralogical composition (magnetite and/or titanomagnetite, hematite and/or titanohematite, and titanomaghemite) and grain size. These data permit investigation of magnetic domain state and magnetization acquisition processes and to assess their significance as a source of magnetic anomalies. Chemical remanent magnetization (CRM) seems to be present in most of investigated ore and wall-rock samples, substituting completely or partially the original thermoremanent magnetization (TRM). Magnetite (or Ti-poor titanomagnetite) and titanohematite are commonly found in the ores. Although hematite may carry a stable CRM, no secondary components are detected above 580 °C, which probably attests that oxidation occurred soon after the extrusion and cooling of the ore-bearing magma. The microscopy study under reflected light shows that magnetic carriers are mainly titanomagnetite with significant amounts of ilmenite-hematite minerals. Magmatic titanomagnetite, found in igneous rocks, shows trellis texture, which is compatible with high temperature (deuteric) oxy-exsolution processes. Hydrothermal alteration in ore deposits is indicated by goethite and hematite oxide minerals. Grain sizes range from a few microns to >100 ?m, and possible magnetic states from single to multidomain, in agreement with hysteresis measurements. Thermal spectra, continuous susceptibility measurements, and isothermal remanent magnetization acquisition suggest a predominance of spinels as magnetic carriers, most probably titanomagnetites with low-Ti content. For quantitative modeling of the magnetic anomaly, we used data on bulk susceptibility and natural remanent intensity for quantifying the relative contributions of induced and remanent magnetization components, and this allows greater control of the geometry of source bodies. The position and geometry of these magnetic sources are shown as ENE-striking tabular bodies, one steeply inclined (75°) to the south and another lying horizontal.

  18. An Integrated Rock Magnetic / Geochemical Approach To Quantify Depletion and Enrichment of Magnetic and Non-magnetic Iron Minerals By Redoxomorphic Diagenesis

    NASA Astrophysics Data System (ADS)

    Funk, J.; von Dobeneck, T.

    Rock magnetic and geochemical data logged by fast, non-destructive X-ray fluores- cence (Fe, Ti) and susceptibility (k) half core scanning techniques have been com- bined to create high-resolution records of redoxomorphic iron mineral diagenesis in suboxic marine sediments. The great potential of this approach and advantage to stan- dard single sample methods is demonstrated on a Late Quaternary sequence from the central Equatorial Atlantic (GeoB 4317-2). Reductive dissolution of ferric minerals, most prominently magnetite (Fe3O4) and hematite (Fe2O3), induced by organic car- bon degradation is shown to represent a gradual, mineral- and grain-size selective process. Proportionality of Fe, Ti and magnetite concentrations in the unaltered sec- tions lead us to define new proxy parameters for magnetite depletion (Fe/k) below and precipitation (k/Ti) above the modern and numerous fossil redox boundaries, while iron relocation was detected on basis of the Fe/Ti ratio. By calibrating all three ratios internally, we can reconstruct and quantify primary deposition and secondary change of both, magnetite and total Fe profiles on basis of the conservative Ti record. Fine- scaled Corg variations (0.1 to 0.6 %) and related susceptibility losses (up to 200*10-6 SI) show high signal resemblance and appear to be equivalent signatures of cyclic pro- ductivity pulses in the study area. Some minor suboxic events are still expressed in the rock magnetic proxy signal, but are not accompanied by residual Corg enrichments, as they have probably undergone oxidation. Enhancement of susceptibility, probably by bacterial biomineralization, takes place in Corg and Fe poor carbonate maxima overlying the magnetically depleted zones. The gain reaches up to 50*10-6 SI and may almost double the Ti derived pristine k value. However in general, susceptibility losses greatly exceed the gains.

  19. Iron and neurodegenerative disorders

    Microsoft Academic Search

    Khristy J Thompson; Shai Shoham; James R Connor

    2001-01-01

    The brain shares with other organs the need for a constant and readily available supply of iron and has a similar array of proteins available to it for iron transport, storage, and regulation. However, unlike other organs, the brain places demands on iron availability that are regional, cellular, and age sensitive. Failure to meet these demands for iron with an

  20. Hepcidin, the iron watcher

    Microsoft Academic Search

    Lydie Viatte; Sophie Vaulont

    2009-01-01

    Hepcidin, a peptide hormone produced by the liver, constitutes the master regulator of iron homeostasis in mammals allowing iron adaptation according to the body iron needs. In recent years there has been important breakthrough in our knowledge of hepcidin regulation that has also implications for understanding the physiopathology of human iron disorders. Different aspects of hepcidin regulation will be considered

  1. Collisional Records in Iron Meteorites

    NASA Astrophysics Data System (ADS)

    Marti, K.; Lavielle, B.; Jeannot, J.-P.

    1995-09-01

    The asteroid belt is considered to be the ultimate source of iron meteorites and it would be of considerable interest to obtain a chronology of break-ups of asteroidal objects. However, as multiple fragmentation of such objects did likely occur, the exposure ages date the break-off of iron masses from shielded locations within the immediate parent object. Meteorites which were fragmented in more than one collisional event may have recorded integral effects of cosmic ray interactions in varying geometrical configuration and individual stages may be difficult to unravel; we term such exposure histories "complex". Exposure age histograms based on potassium ages have been discussed by Voshage [1] and he concluded that irons of groups IIIA and IIIB reveal similar histograms and probably were derived from the same parent body. He also noted a cluster for group IVA members ,but no clear evidence for other clusters. We present the collisional evidence based on published noble gas data, coupled to the new production rates which we calculate for central locations, adjusted for off-center locations whenever concentration profiles can be inferred. Unlike potassium ages which show large uncertainties for ages < 300 Ma, T38 ages can be obtained for all iron meteorites. We note, however,that T38 values of five "old" irons are systematically 15% lower than potassium ages. We confirm the evidence for stochastic events for IIIAB and IVA irons. The statistics are improved because of the larger data base. There are interesting clusters also among ages < 100 Ma, in the range which overlaps the histograms of chondrites. Recent reports [2,3] of H-chondritic inclusions in IIE irons, whose exposure ages are consistent with H-chondrite clusters, point to a genetic link. Group IIAB reveals two clusters with T38 < 100 Ma, and both events appear to involve also IIE irons. Clusterings of two thirds of group IIIE members and of group IID irons appear significant. The youngest IVB ages coincide with the IVA peak at 380 Ma. The fitting algorithm used in our calibrations requires that non-complex Ar- ages and K-ages on average are the same. The ratios of the two ages range from 0.85 to 1.15. This variation roughly corresponds to the uncertainties in measured M values and in Ar concentrations. References: [1] Voshage H. (1978) EPSL, 40, 83-90. [2] Olsen E. et al. (1994) Meteoritics, 29, 200. [3] Casanova I. et al. (1995) Science, 268, 540.

  2. [Iron and pregnancy].

    PubMed

    Beaufrère, B; Bresson, J L; Briend, A; Farriaux, J P; Ghisolfi, J; Navarro, J; Rey, J; Ricour, C; Rieu, D; Vidailhet, M

    1995-12-01

    Infants, young children, and childbearing aged women are particularly exposed to iron deficiency. Pregnancy further increases iron requirements. Nevertheless the consequences of anemia and/or iron deficiency on pregnancy outcome, development of the foetus and postnatal iron status of the infant, remain to be determined. There is a 3-fold increase of premature deliveries in iron deficient anemic pregnant women whose anemia is discovered in early pregnancy: however this increased risk of premature delivery is not observed when iron deficiency anemia is discovered in late pregnancy. Iron supplementation during pregnancy improves the maternal hematological parameters but it is still unclear whether it also improves the maternal health and the pre and postnatal development of the child. Based on our actual knowledge, iron supplementation during pregnancy is to be recommended in risk groups only (ie mainly adolescents, low income women, women with multiple pregnancies), using ferrous iron at a dosage of 30 mg per day. PMID:8548003

  3. Ocean iron cycle

    NASA Astrophysics Data System (ADS)

    Boyd, Philip W.

    Interest in the biogeochemical cycle of iron has grown rapidly over the last two decades, due to the potential role of this element in modulating global climate in the geological past and ocean productivity in the present day. This trace metal has a disproportionately large effect (1 × 105 C:Fe) on photosynthetic carbon fixation by phytoplankton. In around one third of the open ocean, so-called high-nitrate low-chlorophyll (HNLC) regions, the resident phytoplankton have low growth rates despite an abundance of plant nutrients. This is due to the low supply of iron. Iron is present in the ocean in three phases, dissolved, colloidal, and particulate (biogenic and lithogenic). However, iron chemistry is complex with interactions between chemistry and biology such as the production of iron-binding siderophores by oceanic bacteria. This results in the interplay of inorganic chemistry, photochemistry, and organic complexation. Sources of new iron include dust deposition, upwelling of iron-rich deep waters, and the resuspension and lateral transport of sediments. Sinks for iron are mainly biological as evidenced by the vertical nutrient-like profile for dissolved iron in the ocean. Iron is rapidly recycled by the upper ocean biota within a so-called "ferrous wheel." The fe ratio [(new iron)/(new + regenerated iron)] provides an index of the relative supply of iron to the biota by new versus recycled iron. Over the last 15 years, interest in the potential role of iron in shaping climate in the geological past resulted in some of the most ambitious experiments in oceanography: large-scale (i.e., 50-1000 km2) iron enrichment of HNLC waters. They have provided valuable insights into how iron supply influences the biogeochemical cycles of elements such as carbon, sulfur, silicon, nitrogen, and phosphate.

  4. Iron and copper release in drinking-water distribution systems.

    PubMed

    Shi, Baoyou; Taylor, James S

    2007-09-01

    A large-scale pilot study was carried out to evaluate the impacts of changes in water source and treatment process on iron and copper release in water distribution systems. Finished surface waters, groundwaters, and desalinated waters were produced with seven different treatment systems and supplied to 18 pipe distribution systems (PDSs). The major water treatment processes included lime softening, ferric sulfate coagulation, reverse osmosis, nanofiltration, and integrated membrane systems. PDSs were constructed from PVC, lined cast iron, unlined cast iron, and galvanized pipes. Copper pipe loops were set up for corrosion monitoring. Results showed that surface water after ferric sulfate coagulation had low alkalinity and high sulfates, and consequently caused the highest iron release. Finished groundwater treated by conventional method produced the lowest iron release but the highest copper release. The iron release of desalinated water was relatively high because of the water's high chloride level and low alkalinity. Both iron and copper release behaviors were influenced by temperature. PMID:17886579

  5. Taking iron supplements

    MedlinePLUS

    ... streaks Cramps, sharp pains, or soreness in the stomach occur Liquid forms of iron may stain your teeth. Try mixing the iron with water or other liquids (such as fruit juice or tomato juice) and drinking the medicine with ...

  6. Iron supplements (image)

    MedlinePLUS

    The mineral iron is an essential nutrient for humans because it is part of blood cells, which carry oxygen to all body cells. There is no conclusive evidence that iron supplements contribute to heart attacks.

  7. Ironing out fatigue.

    PubMed

    von Drygalski, Annette; Adamson, John W

    2011-09-22

    Women who are not anemic but who suffer from fatigue may benefit from iron supplementation. In this issue of Blood, Krayenbühl et al provide strong evidence that women complaining of fatigue who were not anemic but who had reduced or absent iron stores were symptomatically improved after receiving parenteral iron. Given the numbers of women who are iron deficient, the findings could find broad application, but work needs to be done to refine the approach to this common problem. PMID:21940826

  8. Iron in diet

    MedlinePLUS

    Diet - iron ... the body. Treatment consists of a low-iron diet, no iron supplements, and phlebotomy (blood removal) on ... The Food and Nutrition Board at the Institute of Medicine recommends the following: Infants and children Younger than 6 months: 0.27 milligrams ...

  9. Iron accumulation and enhanced growth in transgenic lettuce plants expressing the iron- binding protein ferritin

    Microsoft Academic Search

    F. Goto; T. Yoshihara; H. Saiki

    2000-01-01

    We have produced transgenic lettuce plants accumulating the iron storage protein ferritin. The integration of the ferritin\\u000a gene and expression levels in leaves were examined by Southern- and Western-blot analysis, respectively. It was shown that\\u000a transgenic lettuce plants contained iron levels ranging from 1.2 to 1.7 times that of the control plants, however, the manganese\\u000a content in transgenic lettuce plants

  10. Ironing out cancer.

    PubMed

    Torti, Suzy V; Torti, Frank M

    2011-03-01

    New insights into the roles of proteins that regulate cellular iron in cancer growth, angiogenesis, and metastasis have recently emerged. Discoveries of the roles of ferroportin, hepcidin, lipocalin 2, and members of the six transmembrane epithelial antigen of the prostate (STEAP) and iron regulatory protein (IRP) families in cancer have provided specificity and molecular definition to the role of iron homeostasis in cancer growth and metastasis. A number of studies directly support a role of these proteins in modifying bioavailable iron, whereas other studies suggest that at least some of their effects are independent of their role in iron biology. PMID:21363917

  11. Iron, radiation, and cancer.

    PubMed Central

    Stevens, R G; Kalkwarf, D R

    1990-01-01

    Increased iron content of cells and tissue may increase the risk of cancer. In particular, high available iron status may increase the risk of a radiation-induced cancer. There are two possible mechanisms for this effect: iron can catalyze the production of oxygen radicals, and it may be a limiting nutrient to the growth and development of a transformed cell in vivo. Given the high available iron content of the western diet and the fact that the world is changing to the western model, it is important to determine if high iron increases the risk of cancer. PMID:2269234

  12. Hepcidin, the iron watcher.

    PubMed

    Viatte, Lydie; Vaulont, Sophie

    2009-10-01

    Hepcidin, a peptide hormone produced by the liver, constitutes the master regulator of iron homeostasis in mammals allowing iron adaptation according to the body iron needs. In recent years there has been important breakthrough in our knowledge of hepcidin regulation that has also implications for understanding the physiopathology of human iron disorders. Different aspects of hepcidin regulation will be considered in this review, including regulation by the iron status and the BMP6/HJV/SMAD pathway. Hepcidin dysregulation in iron disorders will be also discussed. Although much can already be accomplished for treating iron disorders using the knowledge that has currently been developed, additional issues will be challenging for the coming years. PMID:19555735

  13. Treatment of mature landfill leachate by internal micro-electrolysis integrated with coagulation: a comparative study on a novel sequencing batch reactor based on zero valent iron.

    PubMed

    Ying, Diwen; Peng, Juan; Xu, Xinyan; Li, Kan; Wang, Yalin; Jia, Jinping

    2012-08-30

    A comparative study of treating mature landfill leachate with various treatment processes was conducted to investigate whether the method of combined processes of internal micro-electrolysis (IME) without aeration and IME with full aeration in one reactor was an efficient treatment for mature landfill leachate. A specifically designed novel sequencing batch internal micro-electrolysis reactor (SIME) with the latest automation technology was employed in the experiment. Experimental data showed that combined processes obtained a high COD removal efficiency of 73.7 ± 1.3%, which was 15.2% and 24.8% higher than that of the IME with and without aeration, respectively. The SIME reactor also exhibited a COD removal efficiency of 86.1 ± 3.8% to mature landfill leachate in the continuous operation, which is much higher (p<0.05) than that of conventional treatments of electrolysis (22.8-47.0%), coagulation-sedimentation (18.5-22.2%), and the Fenton process (19.9-40.2%), respectively. The innovative concept behind this excellent performance is a combination effect of reductive and oxidative processes of the IME, and the integration electro-coagulation. Optimal operating parameters, including the initial pH, Fe/C mass ratio, air flow rate, and addition of H(2)O(2), were optimized. All results show that the SIME reactor is a promising and efficient technology in treating mature landfill leachate. PMID:22771343

  14. Comparative Study of the Effect of Iron on Citrate-producing Yeast Growing on Different Substrates

    Microsoft Academic Search

    S. Anastassiadis; S. V. Kamzolova; I. G. Morgunov; H. J. Rehm

    2007-01-01

    Little is known about the regulatory mechanisms for citric acid production by different yeast. It is suggested the important role of iron ions in this process; iron is the integral component of many metalloenzymes; such as aconitate-hydratase, catalase, peroxidases and components of mitochondrial electron transfer chain. The response of citric acid metabolism to different iron concentrations was studied with ethanol-

  15. New rat models of iron sucrose-induced iron overload.

    PubMed

    Vu'o'ng Lê, Bá; Khorsi-Cauet, Hafida; Villegier, Anne-Sophie; Bach, Véronique; Gay-Quéheillard, Jérôme

    2011-07-01

    The majority of murine models of iron sucrose-induced iron overload were carried out in adult subjects. This cannot reflect the high risk of iron overload in children who have an increased need for iron. In this study, we developed four experimental iron overload models in young rats using iron sucrose and evaluated different markers of iron overload, tissue oxidative stress and inflammation as its consequences. Iron overload was observed in all iron-treated rats, as evidenced by significant increases in serum iron indices, expression of liver hepcidin gene and total tissue iron content compared with control rats. We also showed that total tissue iron content was mainly associated with the dose of iron whereas serum iron indices depended essentially on the duration of iron administration. However, no differences in tissue inflammatory and antioxidant parameters from controls were observed. Furthermore, only rats exposed to daily iron injection at a dose of 75 mg/kg body weight for one week revealed a significant increase in lipid peroxidation in iron-treated rats compared with their controls. The present results suggest a correlation between iron overload levels and the dose of iron, as well as the duration and frequency of iron injection and confirm that iron sucrose may not play a crucial role in inflammation and oxidative stress. This study provides important information about iron sucrose-induced iron overload in rats and may be useful for iron sucrose therapy for iron deficiency anemia as well as for the prevention and diagnosis of iron sucrose-induced iron overload in pediatric patients. PMID:21685238

  16. The ubiquity of iron.

    PubMed

    Frey, Perry A; Reed, George H

    2012-09-21

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

  17. Iron and iron-based alloys for temporary cardiovascular applications.

    PubMed

    Francis, A; Yang, Y; Virtanen, S; Boccaccini, A R

    2015-03-01

    In the last decade, biodegradable metals have emerged as a topic of interest for particular biomedical applications which require high strength to bulk ratio, including for cardiovascular stents. The advantages of biodegradable materials are related to the reduction of long term risks associated with the presence of permanent metal implants, e.g. chronic inflammation and in-stent restenosis. From a structural point of view, the analysis of the literature reveals that iron-based alloys used as temporary biodegradable stents have several advantages over Mg-based alloys in terms of ductility and strength. Efforts on the modification and tunability of iron-based alloys design and compositions have been mainly focused on controlling the degradation rate while retaining the mechanical integrity within a reasonable period. The early pre-clinical results of many iron-based alloys seem promising for future implants developments. This review discusses the available literature focusing mainly on: (i) Fe and Fe-based alloys design and fabrication techniques; (ii) in vitro and in vivo performance; (iii) cytotoxicity and cell viability tests. PMID:25716025

  18. Thermodynamic properties of Iron—Tellurium alloys

    Microsoft Academic Search

    H. Ipser; K. L. Komarek

    1974-01-01

    Vapor pressures of tellurium of iron—tellurium alloys were determined between 550 and 900°C and between 0 and 67 at % Te by an isopiestic method. Activities and partial molar enthalpies of tellurium were calculated and integral free energies of formation were obtained by aGibbs-Duhem integration. Two statistical models were used to calculate activities in the hexagonal d'-NiAs phase. Excellent agreement

  19. Electrolytic iron or ferrous sulfate increase body iron in women with moderate to low iron stores.

    PubMed

    Swain, James H; Johnson, LuAnn K; Hunt, Janet R

    2007-03-01

    Commercial elemental iron powders (electrolytic and reduced iron), as well as heme iron supplements, were tested for efficacy in improving the iron status of women. In a randomized, double-blind trial, 51 women with moderate to low iron stores received daily for 12 wk: 1) placebo, 2) 5 mg iron as heme iron or 50 mg iron as 3) electrolytic iron, 4) reduced iron, or 5) FeSO(4). Treatments were provided in 2 capsules (heme carrier) and 3 wheat rolls (other iron sources). Differences in iron status, food nonheme iron absorption, and fecal properties were evaluated. Body iron, assessed from the serum transferrin receptor:ferritin ratio, increased significantly more in subjects administered FeSO(4) (127 +/- 29 mg; mean +/- SEM) and electrolytic (115 +/- 37 mg), but not the reduced (74 +/- 32 mg) or heme (65 +/- 26 mg) iron forms, compared with those given placebo (2 +/- 19 mg). Based on body iron determinations, retention of the added iron was estimated as 3.0, 2.7, 1.8, and 15.5%, in the 4 iron-treated groups, respectively. Iron treatments did not affect food iron absorption. The 50 mg/d iron treatments increased fecal iron and free radical-generating capacity in vitro, but did not affect fecal water cytotoxicity. In subjects administered FeSO(4), fecal water content was increased slightly but significantly more than in the placebo group. In conclusion, electrolytic iron was approximately 86% as efficacious as FeSO(4) for improving body iron, but the power of this study was insufficient to detect any efficacy of the reduced or heme iron within 12 wk. With modification, this methodology of testing higher levels of food fortification for several weeks in healthy women with low iron stores has the potential for economically assessing the efficiency of iron compounds to improve iron status. PMID:17311950

  20. Iron Pill–Induced Gastritis

    PubMed Central

    Proksell, Siobhan; Kuan, Shih-Fan; Behari, Jaideep

    2013-01-01

    Iron-deficiency anemia is a prevalent condition treated with iron supplementation. Iron pill–induced gastritis is an under-recognized, albeit serious potential complication of iron pill ingestion. This entity must be identified by healthcare providers who prescribe iron. We present a case of a 59-year-old male with iron deficiency anemia on ferrous sulfate tablets who underwent an upper endoscopy, during which a single superficial gastric ulceration in the body was noted. Biopsies revealed heavy iron deposition confirming the ulceration was a consequence of the iron tablets. Iron pill–induced gastritis causes corrosive mucosal injury similar to that caused by chemical burns.

  1. Comparative Evaluation of Nephrotoxicity and Management by Macrophages of Intravenous Pharmaceutical Iron Formulations

    PubMed Central

    Connor, James R.; Zhang, Xuesheng; Nixon, Anne M.; Webb, Becky; Perno, Joseph R.

    2015-01-01

    Background There is a significant clinical need for effective treatment of iron deficiency. A number of compounds that can be administered intravenously have been developed. This study examines how the compounds are handled by macrophages and their relative potential to provoke oxidative stress. Methods Human kidney (HK-2) cells, rat peritoneal macrophages and renal cortical homogenates were exposed to pharmaceutical iron preparations. Analyses were performed for indices of oxidative stress and cell integrity. In addition, in macrophages, iron uptake and release and cytokine secretion was monitored. Results HK-2 cell viability was decreased by iron isomaltoside and ferumoxytol and all compounds induced lipid peroxidation. In the renal cortical homogenates, lipid peroxidation occurred at lowest concentrations with ferric carboxymaltose, iron dextran, iron sucrose and sodium ferric gluconate. In the macrophages, iron sucrose caused loss of cell viability. Iron uptake was highest for ferumoxytol and iron isomaltoside and lowest for iron sucrose and sodium ferric gluconate. Iron was released as secretion of ferritin or as ferrous iron via ferroportin. The latter was blocked by hepcidin. Exposure to ferric carboxymaltose and iron dextran resulted in release of tumor necrosis factor ?. Conclusions Exposure to iron compounds increased cell stress but was tissue and dose dependent. There was a clear difference in the handling of iron from the different compounds by macrophages that suggests in vivo responses may differ. PMID:25973894

  2. Iron sensors and signals in response to iron deficiency.

    PubMed

    Kobayashi, Takanori; Nishizawa, Naoko K

    2014-07-01

    The transcription of genes involved in iron acquisition in plants is induced under iron deficiency, but our understanding of iron sensors and signals remains limited. Iron Deficiency-responsive Element-binding Factor 1 (IDEF1) and Hemerythrin motif-containing Really Interesting New Gene- and Zinc-finger proteins (HRZs)/BRUTUS (BTS) have recently emerged as candidate iron sensors because of their functions as potent regulators of iron deficiency responses and their iron-binding properties. IDEF1 is a central transcriptional regulator of graminaceous genes involved in iron uptake and utilization, predominantly during the early stages of iron deficiency. HRZs/BTS are E3 ubiquitin ligases and negative regulators of iron deficiency responses in both graminaceous and non-graminaceous plants. Rice OsHRZ1 and OsHRZ2 are also potent regulators of iron accumulation. Characterizing these putative iron sensors also provides clues to understanding the nature of iron signals, which may involve ionized iron itself, other metals, oxygen, redox status, heme and iron-sulfur clusters, in addition to metabolites affected by iron deficiency. Systemic iron responses may also be regulated by phloem-mobile iron and its chelators such as nicotianamine. Iron sensors and signals will be identified by demonstration of signal transmission by IDEF1, HRZs/BTS, or unknown factors. PMID:24908504

  3. Iron in the brain

    Microsoft Academic Search

    Jolanta Galazka-Friedman; Andrzej Friedman; Erika R. Bauminger

    2009-01-01

    The results of our studies of iron in three brain structures, substantia nigra (SN), globus pallidus (GP), and hippocampus\\u000a (Hip), are presented. Mössbauer spectroscopy, electron microscopy and ELISA (enzyme-linked immuno-absorbent assay) were applied.\\u000a Mössbauer studies show that most of the iron in the brain is ferritin-like. The concentration of iron is similar in SN and\\u000a GP, but less than half

  4. Iron in the brain

    Microsoft Academic Search

    Jolanta Galazka-Friedman; Andrzej Friedman; Erika R. Bauminger

    The results of our studies of iron in three brain structures, substantia nigra (SN), globus pallidus (GP), and hippocampus\\u000a (Hip), are presented. Mössbauer spectroscopy, electron microscopy and ELISA (enzyme-linked immuno-absorbent assay) were applied.\\u000a Mössbauer studies show that most of the iron in the brain is ferritin-like. The concentration of iron is similar in SN and\\u000a GP, but less than half

  5. Genomic insights into microbial iron oxidation and iron uptake strategies in extremely acidic environments.

    PubMed

    Bonnefoy, Violaine; Holmes, David S

    2012-07-01

    This minireview presents recent advances in our understanding of iron oxidation and homeostasis in acidophilic Bacteria and Archaea. These processes influence the flux of metals and nutrients in pristine and man-made acidic environments such as acid mine drainage and industrial bioleaching operations. Acidophiles are also being studied to understand life in extreme conditions and their role in the generation of biomarkers used in the search for evidence of existing or past extra-terrestrial life. Iron oxidation in acidophiles is best understood in the model organism Acidithiobacillus ferrooxidans. However, recent functional genomic analysis of acidophiles is leading to a deeper appreciation of the diversity of acidophilic iron-oxidizing pathways. Although it is too early to paint a detailed picture of the role played by lateral gene transfer in the evolution of iron oxidation, emerging evidence tends to support the view that iron oxidation arose independently more than once in evolution. Acidic environments are generally rich in soluble iron and extreme acidophiles (e.g. the Leptospirillum genus) have considerably fewer iron uptake systems compared with neutrophiles. However, some acidophiles have been shown to grow as high as pH 6 and, in the case of the Acidithiobacillus genus, to have multiple iron uptake systems. This could be an adaption allowing them to respond to different iron concentrations via the use of a multiplicity of different siderophores. Both Leptospirillum spp. and Acidithiobacillus spp. are predicted to synthesize the acid stable citrate siderophore for Fe(III) uptake. In addition, both groups have predicted receptors for siderophores produced by other microorganisms, suggesting that competition for iron occurs influencing the ecophysiology of acidic environments. Little is known about the genetic regulation of iron oxidation and iron uptake in acidophiles, especially how the use of iron as an energy source is balanced with its need to take up iron for metabolism. It is anticipated that integrated and complex regulatory networks sensing different environmental signals, such as the energy source and/or the redox state of the cell as well as the oxygen availability, are involved. PMID:22050575

  6. 35. GREY IRON TUMBLERS, IN THE GREY IRON FOUNDRY ROTATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. GREY IRON TUMBLERS, IN THE GREY IRON FOUNDRY ROTATE CASTINGS WITH SHOT TO REMOVE AND SURFACE OXIDES AND REMAINING EXCESS METALS. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  7. Physiology of iron metabolism.

    PubMed

    Waldvogel-Abramowski, Sophie; Waeber, Gérard; Gassner, Christoph; Buser, Andreas; Frey, Beat M; Favrat, Bernard; Tissot, Jean-Daniel

    2014-06-01

    A revolution occurred during the last decade in the comprehension of the physiology as well as in the physiopathology of iron metabolism. The purpose of this review is to summarize the recent knowledge that has accumulated, allowing a better comprehension of the mechanisms implicated in iron homeostasis. Iron metabolism is very fine tuned. The free molecule is very toxic; therefore, complex regulatory mechanisms have been developed in mammalian to insure adequate intestinal absorption, transportation, utilization, and elimination. 'Ironomics' certainly will be the future of the understanding of genes as well as of the protein-protein interactions involved in iron metabolism. PMID:25053935

  8. Physics of iron

    SciTech Connect

    Anderson, O.

    1993-10-01

    This volume comprises papers presented at the AIRAPT Conference, June 28 to July 1993. The iron sessions at the meeting were identified as the Second Ironworkers Convention. The renewal of interest stems from advances in technologies in both diamond-anvil cell (DAC) and shock wave studies as well as from controversies arising from a lack of consensus among both experimentalists and theoreticians. These advances have produced new data on iron in the pressure-temperature regime of interest for phase diagrams and for temperatures of the core/mantle and inner-core/outer-core boundaries. Particularly interesting is the iron phase diagram inferred from DAC studies. A new phase, {beta}, with a {gamma}-{beta}-{epsilon} triple point at about 30 GPa and 1190 K, and possible sixth phase, {omega}, with an {epsilon}-{Theta}-melt triple point at about 190 GPa and 4000 K are deemed possible. The importance of the equation of state of iron in consideration of Earth`s heat budget and the origin of its magnetic field invoke the interest of theoreticians who argue on the basis of molecular dynamics and other first principles methods. While the major thrust of both meetings was on the physics of pure iron, there was notable contributions on iron alloys. Hydrogen-iron alloys, iron-sulfur liquids, and the comparability to rhenium in phase diagram studies are discussed. The knowledge of the physical properties of iron were increased by several contributions.

  9. Objectives and Methods of Iron Chelation Therapy

    PubMed Central

    Hershko, C.; Abrahamov, A.; Konijn, A. M.; Breuer, W.; Cabantchik, I. Z.; Pootrakul, P.; Link, G.

    2003-01-01

    Recent developments in the understanding of the molecular control of iron homeostasis provided novel insights into the mechanisms responsible for normal iron balance. However in chronic anemias associated with iron overload, such mechanisms are no longer sufficient to offer protection from iron toxicity, and iron chelating therapy is the only method available for preventing early death caused mainly by myocardial and hepatic damage. Today, long-term deferoxamine (DFO) therapy is an integral part of the management of thalassemia and other transfusion-dependent anemias, with a major impact on well-being and survival. However, the high cost and rigorous requirements of DFO therapy, and the significant toxicity of deferiprone underline the need for the continued development of new and improved orally effective iron chelators. Within recent years more than one thousand candidate compounds have been screened in animal models. The most outstanding of these compounds include deferiprone (L1); pyridoxal isonicotinoyl hydrazone (PIH) and; bishydroxy- phenyl thiazole. Deferiprone has been used extensively as a substitute for DFO in clinical trials involving hundreds of patients. However, L1 treatment alone fails to achieve a negative iron balance in a substantial proportion of subjects. Deferiprone is less effective than DFO and its potential hepatotoxicity is an issue of current controversy. A new orally effective iron chelator should not necessarily be regarded as one displacing the presently accepted and highly effective parenteral drug DFO. Rather, it could be employed to extend the scope of iron chelating strategies in a manner analogous with the combined use of medications in the management of other conditions such as hypertension or diabetes. Coadministration or alternating use of DFO and a suitable oral chelator may allow a decrease in dosage of both drugs and improve compliance by decreasing the demand on tedious parenteral drug administration. Combined use of DFO and L1 has already been shown to result in successful depletion of iron stores in patients previously failing to respond to single drug therapy, and to lead to improved compliance with treatment. It may also result in a “shuttle effect” between weak intracellular chelators and powerful extracellular chelators or exploit the entero-hepatic cycle to promote fecal iron excretion. All of these innovative ways of chelator usage are now awaiting evaluation in experimental models and in the clinical setting. PMID:18365050

  10. The case for iron

    Microsoft Academic Search

    JOHN H. MARTIN; R. MICHAEL GORDON; STEVE E. FITZWATER

    1991-01-01

    Excess major nutrients occur in offshore areas ranging from the tropical equatorial Pacific to the polar Antarctic. In spite of the great ecological differences in these environments, the authors believe they share a common trait: iron deficiency. Here they present the case of iron; they point out that all of these areas are far from Fe-rich terrestrial sources and that

  11. Iron efficiency in sorghum

    E-print Network

    Esty, James Craig

    1979-01-01

    use of iron by two soy- bean genotypes and their isolines. Agron. J. 59:459-462. 24. Chancy, Rufus L. , John C. Brown, and Lee O. Tiffin. 1972. Obligator'y reduction of ferric che'. ates in iron uptake by soybeans. Plant Physiol. , 50:208-213. 25...

  12. Iron studies in hemophilia

    SciTech Connect

    Lottenberg, R.; Kitchens, C.S.; Roessler, G.S.; Noyes, W.D.

    1981-12-01

    Although iron deficiency is not recognized as a usual complication of hemophilia, we questioned whether intermittent occult loss of blood in urine or stool might predispose hemophiliacs to chronic iron deficiency. Seven men with factor VII and one with factor IX deficiency were studied. Blood studied, bone marrow aspirates, urine and stool samples, and ferrokinetics with total-body counting up to five months were examined. These data showed no excessive loss of blood during the study period; however, marrow iron stores were decidedly decreased, being absent in four subjects. We suggest that in some hemophiliacs, iron deposits in tissues such as synovial membranes may form a high proportion of the body's total iron stores.

  13. The effect of iron dilution on strength of nickel/steel and Monel/steel welds

    SciTech Connect

    Fout, S.L.; Wamsley, S.D.

    1983-03-28

    The weld strength, as a function of iron content, for nickel/steel and Monel/steel welds was determined. Samples were prepared using a Gas Metal Arc (GMAW) automatic process to weld steel plate together with nickel or Monel to produce a range of iron contents typical of weld compositions. Tensile specimens of each iron content were tested to obtain strength and ductility measurements for that weld composition. Data indicate that at iron contents of less than 20% iron in a nickel/steel weld, the weld fails at the weld interface, due to a lack of fusion. Between 20% and 35% iron, the highest iron dilution that could be achieved in a nickel weld, the welds were stronger than the steel base metal. This indicates that a minimum amount of iron dilution (20%) is necessary for good fusion and optimum strength. On the other hand for Monel/steel welds, test results showed that the welds had good strength and integrity between 10% and 27% iron in the weld. Above 35% iron, the welds have less strength and are more brittle. The 35% iron content also corresponds to the iron dilution in Monel welds that has been shown to produce an increase in corrosion rate. This indicates that the iron dilution in Monel welds should be kept below 35% iron to maximize both the strength and corrosion resistance. 2 refs., 6 figs., 3 tabs.

  14. 21 CFR 310.518 - Drug products containing iron or iron salts.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...false Drug products containing iron or iron salts. 310.518 Section 310.518 Food...518 Drug products containing iron or iron salts. Drug products containing elemental iron or iron salts as an active ingredient in solid oral...

  15. 21 CFR 310.518 - Drug products containing iron or iron salts.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...false Drug products containing iron or iron salts. 310.518 Section 310.518 Food...518 Drug products containing iron or iron salts. Drug products containing elemental iron or iron salts as an active ingredient in solid oral...

  16. 21 CFR 310.518 - Drug products containing iron or iron salts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...false Drug products containing iron or iron salts. 310.518 Section 310.518 Food...518 Drug products containing iron or iron salts. Drug products containing elemental iron or iron salts as an active ingredient in solid oral...

  17. 21 CFR 310.518 - Drug products containing iron or iron salts.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...false Drug products containing iron or iron salts. 310.518 Section 310.518 Food...518 Drug products containing iron or iron salts. Drug products containing elemental iron or iron salts as an active ingredient in solid oral...

  18. 21 CFR 310.518 - Drug products containing iron or iron salts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...false Drug products containing iron or iron salts. 310.518 Section 310.518 Food...518 Drug products containing iron or iron salts. Drug products containing elemental iron or iron salts as an active ingredient in solid oral...

  19. Electrolytic Iron or Ferrous Sulfate Increase Body Iron in Women with Moderate to Low

    Microsoft Academic Search

    James H. Swain; LuAnn K. Johnson; Janet R. Hunt

    Commercial elemental iron powders (electrolytic and reduced iron), as well as heme iron supplements, were tested for efficacy in improving the iron status of women. In a randomized, double-blind trial, 51 women with moderate to low iron stores received daily for 12 wk: 1) placebo,2) 5 mg iron as heme iron or 50 mg iron as 3) electrolytic iron, 4)

  20. Molecular control of vertebrate iron homeostasis by iron regulatory proteins

    PubMed Central

    Wallander, Michelle L.; Leibold, Elizabeth A.; Eisenstein, Richard S.

    2008-01-01

    Both deficiencies and excesses of iron represent major public health problems throughout the world. Understanding the cellular and organismal processes controlling iron homeostasis is critical for identifying iron-related diseases and in advancing the clinical treatments for such disorders of iron metabolism. Iron regulatory proteins (IRPs) 1 and 2 are key regulators of vertebrate iron metabolism. These RNA binding proteins post-transcriptionally control the stability or translation of mRNAs encoding proteins involved in iron homeostasis thereby controlling the uptake, utilization, storage or export of iron. Recent evidence provides insight into how IRPs selectively control the translation or stability of target mRNAs, how IRP RNA binding activity is controlled by iron-dependent and iron-independent effectors, and the pathological consequences of dysregulation of the IRP system. PMID:16872694

  1. Iron in Cereal

    NSDL National Science Digital Library

    Mid-continent Research for Education and Learning (McREL)

    2004-01-01

    Is there really iron in breakfast cereal? This material is part of a series of hands-on science activities designed to arouse student interest. Here students investigate the removal of iron from a box of high-iron content breakfast cereal. The activity includes a description, a list of science process skills being covered, complex reasoning strategies that are used, and a compilation of national science standards about this activity. Also provided are content topics, a list of necessary supplies and instructions to perform the activity, and presentation techniques. An explanation of the content of each activity and assessment suggestions are provided. Copyright 2005 Eisenhower National Clearinghouse

  2. Electronic effects on iron porphyrins

    SciTech Connect

    Rosa, M. De La; Lopez, M.A. [California State Univ., Long Beach, CA (United States)

    1995-12-31

    We have inserted iron into a series of substituted iron tetraphenylporphyrins for the purposes of investigating electronic effects on properties of the iron porphyrins. The properties of interest are the CO stretching frequencies of the ferrous porphyrins, the rates of CO dissociation from the ferrous porphyrins, and the UV-visible spectra of the iron porphyrins. We will present our results to date.

  3. Coal desulfurization. [using iron pentacarbonyl

    NASA Technical Reports Server (NTRS)

    Hsu, G. C. (inventor)

    1979-01-01

    Organic sulfur is removed from coal by treatment with an organic solution of iron pentacarbonyl. Organic sulfur compounds can be removed by reaction of the iron pentacarbonyl with coal to generate CO and COS off-gases. The CO gas separated from COS can be passed over hot iron fillings to generate iron pentacarbonyl.

  4. Molecular Structure of Iron Monoxide

    NSDL National Science Digital Library

    2003-06-04

    Iron monoxide is an odorless black powder. Technologies and uses of iron and iron oxide powders have progressed steadily. Synthetic iron oxide powders are used primarily for pigmentary and magnetic properties. These powders are inexpensive to make and are used to color concrete products, paints, plastics and other media.

  5. Good Sources of Nutrients: Iron

    E-print Network

    Scott, Amanda; Replogle, Jacqueline

    2008-08-28

    Iron is a mineral that functions primarily to carry oxygen in the body. This publication explains how people can get enough iron in their diets and how to prepare foods to retain iron. It also lists foods that are good sources of iron. (2 pp., 2...

  6. Iron overload and chelation therapy in myelodysplastic syndromes.

    PubMed

    Temraz, Sally; Santini, Valeria; Musallam, Khaled; Taher, Ali

    2014-07-01

    Iron overload remains a concern in MDS patients especially those requiring recurrent blood transfusions. The consequence of iron overload may be more relevant in patients with low and intermediate-1 risk MDS who may survive long enough to experience such manifestations. It is a matter of debate whether this overload has time to yield organ damage, but it is quite evident that cellular damage and DNA genotoxic effect are induced. Iron overload may play a critical role in exacerbating pre-existing morbidity or even unmask silent ones. Under these circumstances, iron chelation therapy could play an integral role in the management of these patients. This review entails an in depth analysis of iron overload in MDS patients; its pathophysiology, effect on survival, associated risks and diagnostic options. It also discusses management options in relation to chelation therapy used in MDS patients and the impact it has on survival, hematologic response and organ function. PMID:24529413

  7. Iron supplementation in renal anemia.

    PubMed

    Fishbane, Steven

    2006-07-01

    Iron-deficiency frequently develops in patients with chronic kidney disease who are treated with recombinant human erythropoietin (rHuEPO). It results in reduced effectiveness of anemia therapy; patients may fail to reach hemoglobin targets or may require excessively large doses of rHuEPO. It has been recognized widely that iron management, monitoring for iron deficiency, and effective iron supplementation forms a core component of anemia therapy. This review discusses the physiology of iron balance, derangements in iron balance in chronic kidney disease (CKD), and the diagnosis and treatment of iron deficiency in patients treated with rHuEPO. PMID:16949471

  8. Formation and Release Behavior of Iron Corrosion Products under the Influence of Bacterial Communities in a Simulated Water Distribution System

    EPA Science Inventory

    Understanding the effects of biofilm on the iron corrosion, iron release and associated corrosion by-products is critical for maintaining the water quality and the integrity of drinking water distribution system (DWDS). In this work, iron corrosion experiments under sterilized a...

  9. Iron deficiency and iron deficiency anemia in women.

    PubMed

    Coad, Jane; Pedley, Kevin

    2014-01-01

    Iron deficiency is one of the most common nutritional problems in the world and disproportionately affects women and children. Stages of iron deficiency can be characterized as mild deficiency where iron stores become depleted, marginal deficiency where the production of many iron-dependent proteins is compromised but hemoglobin levels are normal and iron deficiency anemia where synthesis of hemoglobin is decreased and oxygen transport to the tissues is reduced. Iron deficiency anemia is usually assessed by measuring hemoglobin levels but this approach lacks both specificity and sensitivity. Failure to identify and treat earlier stages of iron deficiency is concerning given the neurocognitive implications of iron deficiency without anemia. Most of the daily iron requirement is derived from recycling of senescent erythrocytes by macrophages; only 5-10 % comes from the diet. Iron absorption is affected by inhibitors and enhancers of iron absorption and by the physiological state. Inflammatory conditions, including obesity, can result in iron being retained in the enterocytes and macrophages causing hypoferremia as a strategic defense mechanism to restrict iron availability to pathogens. Premenopausal women usually have low iron status because of iron loss in menstrual blood. Conditions which further increase iron loss, compromise absorption or increase demand, such as frequent blood donation, gastrointestinal lesions, athletic activity and pregnancy, can exceed the capacity of the gastrointestinal tract to upregulate iron absorption. Women of reproductive age are at particularly high risk of iron deficiency and its consequences however there is a controversial argument that evolutionary pressures have resulted in an iron deficient phenotype which protects against infection. PMID:25083899

  10. Chelation therapy for iron overload

    Microsoft Academic Search

    James C. Barton

    2007-01-01

    Iron overload is characterized by excessive iron deposition and consequent injury and dysfunction of the heart, liver, anterior\\u000a pituitary, pancreas, and joints. Because physiologic mechanisms to excrete iron are very limited, patients with iron overload\\u000a and its complications need safe, effective therapy that is compatible with their coexisting medical conditions. The availability\\u000a of three licensed iron chelation drugs (one parenteral,

  11. Dietary and prophylactic iron supplements

    Microsoft Academic Search

    Susan Kent; Eugene D. Weinberg; Patricia Stuart-Macadam

    1990-01-01

    Mild hypoferremia represents an aspect of the ability of the body to withhold iron from pathogenic bacteria, fungi, and protozoa,\\u000a and from neoplastic cells. However, our iron-withholding defense system can be thwarted by practices that enhance iron overload\\u000a such as indiscriminate iron fortification of foods, medically prescribed iron supplements, alcohol ingestion, and cigarette\\u000a smoking. Elevated standards for normal levels of

  12. An Ancient Gauge for Iron

    NSDL National Science Digital Library

    Tracey Rouault (National Institute of Child Health and Human Development; Molecular Medicine Program)

    2009-10-30

    The iron regulatory proteins IRP1 and IRP2 are critical to the import, export, and sequestration of iron for achievement of the cytosolic concentrations needed to support the synthesis of iron-binding proteins and for prevention of unfavorable iron-dependent oxidation events in mammalian cells. This perspective discusses reports by Vashisht et al. and Salahudeen et al. that human cells gauge cellular iron and concomitantly alter the activity of IRPs through a mechanism that depends on the protein FBXL5.

  13. Mössbauer Spectra of Some Iron Complexes

    Microsoft Academic Search

    L. M. Epstein

    1962-01-01

    Mossbauer spectra were obtained for the following coordthation ; compounds: iron phthalocyanine, ferrocene, iron carbonyl, iron HI ; acetylacetonate, and iron II acetylacetonate dipyridine; for the following ; complex ion saIts iron n trisphenanthroline chloride, iron W EDTA Monosodium ; salt), iron II EDTA, hemin, ferricium picrate, sodium nitroprusside, and some ; ferro- and ferricyanides. The isomer shift (relative to

  14. Application of iron magnetic nanoparticles in protein immobilization.

    PubMed

    Xu, Jiakun; Sun, Jingjing; Wang, Yuejun; Sheng, Jun; Wang, Fang; Sun, Mi

    2014-01-01

    Due to their properties such as superparamagnetism, high surface area, large surface-to-volume ratio, easy separation under external magnetic fields, iron magnetic nanoparticles have attracted much attention in the past few decades. Various modification methods have been developed to produce biocompatible magnetic nanoparticles for protein immobilization. This review provides an updated and integrated focus on the fabrication and characterization of suitable magnetic iron nanoparticle-based nano-active materials for protein immobilization. PMID:25093986

  15. Plant cell nucleolus as a hot spot for iron.

    PubMed

    Roschzttardtz, Hannetz; Grillet, Louis; Isaure, Marie-Pierre; Conéjéro, Geneviève; Ortega, Richard; Curie, Catherine; Mari, Stéphane

    2011-08-12

    Many central metabolic processes require iron as a cofactor and take place in specific subcellular compartments such as the mitochondrion or the chloroplast. Proper iron allocation in the different organelles is thus critical to maintain cell function and integrity. To study the dynamics of iron distribution in plant cells, we have sought to identify the different intracellular iron pools by combining three complementary imaging approaches, histochemistry, micro particle-induced x-ray emission, and synchrotron radiation micro X-ray fluorescence. Pea (Pisum sativum) embryo was used as a model in this study because of its large cell size and high iron content. Histochemical staining with ferrocyanide and diaminobenzidine (Perls/diaminobenzidine) strongly labeled a unique structure in each cell, which co-labeled with the DNA fluorescent stain DAPI, thus corresponding to the nucleus. The unexpected presence of iron in the nucleus was confirmed by elemental imaging using micro particle-induced x-ray emission. X-ray fluorescence on cryo-sectioned embryos further established that, quantitatively, the iron concentration found in the nucleus was higher than in the expected iron-rich organelles such as plastids or vacuoles. Moreover, within the nucleus, iron was particularly accumulated in a subcompartment that was identified as the nucleolus as it was shown to transiently disassemble during cell division. Taken together, our data uncover an as yet unidentified although abundant iron pool in the cell, which is located in the nuclei of healthy, actively dividing plant tissues. This result paves the way for the discovery of a novel cellular function for iron related to nucleus/nucleolus-associated processes. PMID:21719700

  16. Possible involvement of iron-induced oxidative insults in neurodegeneration.

    PubMed

    Asano, Takeshi; Koike, Masato; Sakata, Shin-ichi; Takeda, Yukiko; Nakagawa, Tomoko; Hatano, Taku; Ohashi, Satoshi; Funayama, Manabu; Yoshimi, Kenji; Asanuma, Masato; Toyokuni, Shinya; Mochizuki, Hideki; Uchiyama, Yasuo; Hattori, Nobutaka; Iwai, Kazuhiro

    2015-02-19

    Involvement of iron in the development of neurodegenerative disorders has long been suggested, and iron that cannot be stored properly is suggested to induce iron toxicity. To enhance iron uptake and suppress iron storage in neurons, we generated transgenic (Tg) mice expressing iron regulatory protein 2 (IRP2), a major regulator of iron metabolism, in a neuron-specific manner. Although very subtle, IRP2 was expressed in all regions of brain examined. In the Tg mice, mitochondrial oxidative insults were observed including generation of 4-hydroxynonenal modified proteins, which appeared to be removed by a mitochondrial quality control protein Parkin. Inter-crossing of the Tg mice to Parkin knockout mice perturbed the integrity of neurons in the substantia nigra and provoked motor symptoms. These results suggest that a subtle, but chronic increase in IRP2 induces mitochondrial oxidative insults and accelerates neurodegeneration in a mouse model of Parkinson's disease. Thus, the IRP2 Tg may be a useful tool to probe the roles of iron-induced mitochondrial damages in neurodegeraration research. PMID:25549542

  17. Iron transport & homeostasis mechanisms: their role in health & disease.

    PubMed

    Nadadur, S S; Srirama, K; Mudipalli, Anuradha

    2008-10-01

    Iron is an essential trace metal required by all living organisms and is toxic in excess. Nature has evolved a delicately balanced network to monitor iron entry, transport it to sites of need, and serve as a unique storage and recycling system, in the absence of an excretory system, to remove excess iron. Due to the unique nature of iron metabolism, iron homeostasis is achieved by integrated specialized mechanisms that operate at the cellular and organism level. The use of positional cloning approaches by multiple researchers has led to the identification and characterization of various proteins and peptides that play a critical role in iron metabolism. These efforts have led to elucidation of the molecular mechanisms involved in the uptake of iron by the enterocytes, transportation across the membrane to circulation, and delivery to diverse tissues for use and storage and sensor system to co-ordinate and achieve homeostasis. Molecular understanding of these processes and the key regulatory molecules involved in maintaining homeostasis will provide novel insights into understanding human disorders associated with either iron deficiency or overload. PMID:19106445

  18. Cardioprotective activity of iron oxide nanoparticles.

    PubMed

    Xiong, Fei; Wang, Hao; Feng, Yidong; Li, Yunman; Hua, Xiaoqing; Pang, Xingyun; Zhang, Song; Song, Lina; Zhang, Yu; Gu, Ning

    2015-01-01

    Iron oxide nanoparticles (IONPs) are chemically inert materials and have been mainly used for imaging applications and drug deliveries. However, the possibility whether they can be used as therapeutic drugs themselves has not yet been explored. We reported here that Fe2O3 nanoparticles (NPs) can protect hearts from ischemic damage at the animal, tissue and cell level. The cardioprotective activity of Fe2O3 NPs requires the integrity of nanoparticles and is not dependent upon their surface charges and molecules that were integrated into nanoparticles. Also, Fe2O3 NPs showed no significant toxicity towards normal cardiomyocytes, indicative of their potential to treat cardiovascular diseases. PMID:25716309

  19. Cardioprotective activity of iron oxide nanoparticles

    PubMed Central

    Xiong, Fei; Wang, Hao; Feng, Yidong; Li, Yunman; Hua, Xiaoqing; Pang, Xingyun; Zhang, Song; Song, Lina; Zhang, Yu; Gu, Ning

    2015-01-01

    Iron oxide nanoparticles (IONPs) are chemically inert materials and have been mainly used for imaging applications and drug deliveries. However, the possibility whether they can be used as therapeutic drugs themselves has not yet been explored. We reported here that Fe2O3 nanoparticles (NPs) can protect hearts from ischemic damage at the animal, tissue and cell level. The cardioprotective activity of Fe2O3 NPs requires the integrity of nanoparticles and is not dependent upon their surface charges and molecules that were integrated into nanoparticles. Also, Fe2O3 NPs showed no significant toxicity towards normal cardiomyocytes, indicative of their potential to treat cardiovascular diseases. PMID:25716309

  20. Iron loading and disease surveillance.

    PubMed Central

    Weinberg, E. D.

    1999-01-01

    Iron is an oxidant as well as a nutrient for invading microbial and neoplastic cells. Excessive iron in specific tissues and cells (iron loading) promotes development of infection, neoplasia, cardiomyopathy, arthropathy, and various endocrine and possibly neurodegenerative disorders. To contain and detoxify the metal, hosts have evolved an iron withholding defense system, but the system can be compromised by numerous factors. An array of behavioral, medical, and immunologic methods are in place or in development to strengthen iron withholding. Routine screening for iron loading could provide valuable information in epidemiologic, diagnostic, prophylactic, and therapeutic studies of emerging infectious diseases. PMID:10341171

  1. Iron acquisition by Haemophilus influenzae.

    PubMed Central

    Pidcock, K A; Wooten, J A; Daley, B A; Stull, T L

    1988-01-01

    The mechanisms for acquisition of iron by Haemophilus influenzae and their role in pathogenesis are not known. Heme and nonheme sources of iron were evaluated for their effect on growth of type b and nontypable strains of H. influenzae in an iron-restricted, defined medium. All 13 strains acquired iron from heme, hemoglobin, hemoglobin-haptoglobin, and heme-hemopexin. Among nonheme sources of protein-bound iron, growth of H. influenzae was enhanced by partially saturated human transferrin but not by lactoferrin or ferritin. Purified ferrienterochelin and ferridesferrioxamine failed to provide iron to H. influenzae, and the supernatants of H. influenzae E1a grown in iron-restricted medium failed to enhance iron-restricted growth of siderophore-dependent strains of Escherichia coli, Salmonella typhimurium, and Arthrobacter terregens. Marked alterations in the profile of outer membrane proteins of H. influenzae were observed when the level of free iron was varied between 1 microM and 1 mM. Catechols were not detected in the supernatants of strain E1a; however, iron-related hydroxamate production was detected by two biochemical assays. We conclude that the sources of iron for H. influenzae are diverse. The significance of hydroxamate production and iron-related outer membrane proteins to H. influenzae iron acquisition is not yet clear. Images PMID:2964410

  2. Iron biomineralization by anaerobic neutrophilic iron-oxidizing bacteria

    Microsoft Academic Search

    Jennyfer Miot; Karim Benzerara; Guillaume Morin; Andreas Kappler; Sylvain Bernard; Martin Obst; Céline Férard; Fériel Skouri-Panet; Jean-Michel Guigner; Nicole Posth; Matthieu Galvez; Gordon E. Brown; François Guyot

    2009-01-01

    Minerals formed by bio-oxidation of ferrous iron (Fe(II)) at neutral pH, their association with bacterial ultrastructures as well as their impact on the metabolism of iron-oxidizing bacteria remain poorly understood. Here, we investigated iron biomineralization by the anaerobic nitrate-dependent iron-oxidizing bacterium Acidovorax sp. strain BoFeN1 in the presence of dissolved Fe(II) using electron microscopy and Scanning Transmission X-ray Microscopy (STXM).

  3. How Is Iron-Deficiency Anemia Treated?

    MedlinePLUS

    ... the NHLBI on Twitter. How Is Iron-Deficiency Anemia Treated? Treatment for iron-deficiency anemia will depend ... may be advised. Treatments for Severe Iron-Deficiency Anemia Blood Transfusion If your iron-deficiency anemia is ...

  4. INTERIOR VIEW OF IRON TREATMENT (DESULPHURIZATION) AREA. MOLTEN IRON PROCEEDS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW OF IRON TREATMENT (DESULPHURIZATION) AREA. MOLTEN IRON PROCEEDS FROM CUPOLA TO IRON TREATMENT AREAS BEFORE BEING TRANSFERRED TO PIPE CASTING MACHINES. - United States Pipe & Foundry Company Plant, Melting & Treatment Areas, 2023 St. Louis Avenue at I-20/59, Bessemer, Jefferson County, AL

  5. Hydroxamate recognition during iron transport from hydroxamate-iron chelates

    Microsoft Academic Search

    A. H. Haydon; W. B. Davis; E. L. Arceneaux; B. R. Byers

    1973-01-01

    Kinetics of radioactive iron transport from three structurally different ; secondary hydroxandate-iron chelates (schizokineniron, produced by Bacillus ; megaterium ATCC 19213; Desferaliron, produced by an actinomycete; and aerobactin-; iron, produced by Aerobacter aerogenes 62-1) revealed that B. megateriurm SK 11 ; (a mutant that cannot synthesize schizokinen) has a specific transport system for ; utilization of ferric hydroxamates with a

  6. Iron Meteorite on Mars

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA's Mars Exploration Rover Opportunity has found an iron meteorite on Mars, the first meteorite of any type ever identified on another planet. The pitted, basketball-size object is mostly made of iron and nickel. Readings from spectrometers on the rover determined that composition. Opportunity used its panoramic camera to take the images used in this approximately true-color composite on the rover's 339th martian day, or sol (Jan. 6, 2005). This composite combines images taken through the panoramic camera's 600-nanometer (red), 530-nanometer (green), and 480-nanometer (blue) filters.

  7. A Novel Iron-Regulated Metal Transporter from Plants Identified by Functional Expression in Yeast

    Microsoft Academic Search

    David Eide; Margaret Broderius; Janette Fett; Mary Lou Guerinot

    1996-01-01

    Iron is an essential nutrient for virtually all organisms. The IRT1 (iron-regulated transporter) gene of the plant Arabidopsis thaliana, encoding a probable Fe(II) transporter, was cloned by functional expression in a yeast strain defective for iron uptake. Yeast expressing IRT1 possess a novel Fe(II) uptake activity that is strongly inhibited by Cd. IRT1 is predicted to be an integral membrane

  8. Iron in Infection and Immunity

    PubMed Central

    Cassat, James E.; Skaar, Eric P.

    2013-01-01

    Iron is an essential nutrient for both humans and pathogenic microbes. Because of its ability to exist in one of two oxidation states, iron is an ideal redox catalyst for diverse cellular processes including respiration and DNA replication. However, the redox potential of iron also contributes to its toxicity, thus iron concentration and distribution must be carefully controlled. Given the absolute requirement for iron by virtually all human pathogens, an important facet of the innate immune system is to limit iron availability to invading microbes in a process termed nutritional immunity. Successful human pathogens must therefore possess mechanisms to circumvent nutritional immunity in order to cause disease. In this review, we discuss regulation of iron metabolism in the setting of infection and delineate strategies used by human pathogens to overcome iron-withholding defenses. PMID:23684303

  9. Iron and Steel Phosphate Rock

    E-print Network

    Torgersen, Christian

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

  10. Hepcidin Suppresses Brain Iron Accumulation by Downregulating Iron Transport Proteins in Iron-Overloaded Rats.

    PubMed

    Du, Fang; Qian, Zhong-Ming; Luo, Qianqian; Yung, Wing-Ho; Ke, Ya

    2015-08-01

    Iron accumulates progressively in the brain with age, and iron-induced oxidative stress has been considered as one of the initial causes for Alzheimer's disease (AD) and Parkinson's disease (PD). Based on the role of hepcidin in peripheral organs and its expression in the brain, we hypothesized that this peptide has a role to reduce iron in the brain and hence has the potential to prevent or delay brain iron accumulation in iron-associated neurodegenerative disorders. Here, we investigated the effects of hepcidin expression adenovirus (ad-hepcidin) and hepcidin peptide on brain iron contents, iron transport across the brain-blood barrier, iron uptake and release, and also the expression of transferrin receptor-1 (TfR1), divalent metal transporter 1 (DMT1), and ferroportin 1 (Fpn1) in cultured microvascular endothelial cells and neurons. We demonstrated that hepcidin significantly reduced brain iron in iron-overloaded rats and suppressed transport of transferrin-bound iron (Tf-Fe) from the periphery into the brain. Also, the peptide significantly inhibited expression of TfR1, DMT1, and Fpn1 as well as reduced Tf-Fe and non-transferrin-bound iron uptake and iron release in cultured microvascular endothelial cells and neurons, while downregulation of hepcidin with hepcidin siRNA retrovirus generated opposite results. We concluded that, under iron-overload, hepcidin functions to reduce iron in the brain by downregulating iron transport proteins. Upregulation of brain hepcidin by ad-hepcidin emerges as a new pharmacological treatment and prevention for iron-associated neurodegenerative disorders. PMID:25115800

  11. Bordetella iron transport and virulence

    Microsoft Academic Search

    Timothy J. Brickman; Mark T. Anderson; Sandra K. Armstrong

    2007-01-01

    Bordetella pertussis, Bordetella parapertussis, and Bordetella bronchiseptica are pathogens with a complex iron starvation stress response important for adaptation to nutrient limitation and flux in\\u000a the mammalian host environment. The iron starvation stress response is globally regulated by the Fur repressor using ferrous\\u000a iron as the co-repressor. Expression of iron transport system genes of Bordetella is coordinated by priority regulation

  12. Iron deficiency and cognitive functions

    PubMed Central

    Jáuregui-Lobera, Ignacio

    2014-01-01

    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. PMID:25419131

  13. Service experience of refractory products and mixtures in metallurgical plant lining at the Magnitogorsk Metallurgical Works

    Microsoft Academic Search

    G. V. Pol’shchikov; S. P. Sitkin; E. V. Sidorov; V. M. Beloborodov; A. N. Nikiforov

    2007-01-01

    The authors describe the experience of production of refractories and mixtures and their service in blast furnaces and steel\\u000a melting, as well as the service of corundum-graphite products for protecting metal strands on machines for continuous slab\\u000a casting.

  14. The Iron Project

    NASA Technical Reports Server (NTRS)

    Pradhan, Anil K.

    2000-01-01

    Recent advances in theoretical atomic physics have enabled large-scale calculation of atomic parameters for a variety of atomic processes with high degree of precision. The development and application of these methods is the aim of the Iron Project. At present the primary focus is on collisional processes for all ions of iron, Fe I - FeXXVI, and other iron-peak elements; new work on radiative processes has also been initiated. Varied applications of the Iron Project work to X-ray astronomy are discussed, and more general applications to other spectral ranges are pointed out. The IP work forms the basis for more specialized projects such as the RmaX Project, and the work on photoionization/recombination, and aims to provide a comprehensive and self-consistent set of accurate collisional and radiative cross sections, and transition probabilities, within the framework of relativistic close coupling formulation using the Breit-Pauli R-Matrix method. An illustrative example is presented of how the IP data may be utilized in the formation of X-ray spectra of the K alpha complex at 6.7 keV from He-like Fe XXV.

  15. The Rusting of Iron

    Microsoft Academic Search

    Joseph Meehan

    1906-01-01

    IN reference to the discussion on the rusting of iron in recent numbers of NATURE, I happen to have a curious specimen illustrating the accumulating of rust which may possibly be of some little scientific value. It is a horseshoe which was dug up some years ago by a child out of the sand on the site of the battle

  16. Magnetoresistance of Iron Whiskers

    Microsoft Academic Search

    Acar Isin; R. V. Coleman

    1965-01-01

    Transverse magnetoresistance measurements on iron whiskers with axes along , , and have been made in fields up to 50 kOe. Measurements have been made on whiskers with diameters ranging from 40 to 400 mu. Sharp minima observed in the rotation diagrams measured at 50 kOe for all three orientations are consistent with the existence of open orbits along and

  17. Culture's Unacknowledged Iron Grip

    ERIC Educational Resources Information Center

    Engle, John

    2007-01-01

    Ideally, education provides mutual enrichment for professor and students. In this article, the author often fears that he is learning far more than his students are in a course on intercultural communication. Its real subject sometimes seems to be the iron grip of American culture upon his students. What is most fascinating is that the power of…

  18. Ironing out the problem: new mechanisms of iron homeostasis.

    PubMed

    Massé, Eric; Arguin, Mélina

    2005-08-01

    For most organisms, iron is an essential nutrient that is both difficult to acquire from the environment and toxic at high concentration. Therefore, to avoid deprivation or over-abundance of iron, bacteria and eukaryotes have developed a tight regulatory system to keep the metal within a narrow concentration range. Recent work in the bacteria Escherichia coli and in Pseudomonas aeruginosa has demonstrated that small regulatory RNAs function post-transcriptionally to repress iron-using proteins, thereby ensuring that limited iron resources are allocated to crucial cellular functions during iron starvation. Following this discovery, a parallel mechanism that uses a protein and not a small RNA was described in the budding yeast Saccharomyces cerevisiae under iron restriction. The common characteristics of these three different organisms suggest a novel mechanism of iron homeostasis. PMID:15996868

  19. A Bacterial Iron Exporter for Maintenance of Iron Homeostasis*

    PubMed Central

    Sankari, Siva; O'Brian, Mark R.

    2014-01-01

    Nutritional iron acquisition by bacteria is well described, but almost nothing is known about bacterial iron export even though it is likely to be an important homeostatic mechanism. Here, we show that Bradyrhizobium japonicum MbfA (Blr7895) is an inner membrane protein expressed in cells specifically under high iron conditions. MbfA contains an N-terminal ferritin-like domain (FLD) and a C-terminal domain homologous to the eukaryotic vacuolar membrane Fe2+/Mn2+ transporter CCC1. An mbfA deletion mutant is severely defective in iron export activity, contains >2-fold more intracellular iron than the parent strain, and displays an aberrant iron-dependent gene expression phenotype. B. japonicum is highly resistant to iron and H2O2 stresses, and MbfA contributes substantially to this as determined by phenotypes of the mbfA mutant strain. The N-terminal FLD was localized to the cytoplasmic side of the inner membrane. Substitution mutations in the putative iron-binding amino acid residues E20A and E107A within the N-terminal FLD abrogate iron export activity and stress response function. Purified soluble FLD oxidizes ferrous iron (Fe2+) to incorporate ferric iron (Fe3+) in a 2:1 iron:protein ratio, which does not occur in the E20A/E107A mutant. The FLD fragment is a dimer in solution, implying that the MbfA exporter functions as a dimer. MbfA belongs to a protein family found in numerous prokaryotic genera. The findings strongly suggest that iron export plays an important role in bacterial iron homeostasis. PMID:24782310

  20. Novel approaches and application of contemporary sensory evaluation practices in iron fortification programs

    NASA Technical Reports Server (NTRS)

    Bovell-Benjamin, Adelia C.; Guinard, Jean-Xavier

    2003-01-01

    Iron deficiency is the leading nutritional deficiency in the U.S. and the rest of the world, with its highest prevalences in the developing world. Iron fortification of food has been proposed as a strategy to reduce the high prevalence of iron deficiency. Poor consumer acceptance, unacceptable taste, and discoloration of the iron-fortified foods have been frequently listed as causes of unsuccessful iron fortification programs. An excellent prospect for improving consumer acceptance of iron-fortified foods is the incorporation of a thorough, organized, and unified approach to sensory evaluation practices into iron fortification programs for product optimization. The information gained from systematic sensory evaluation allows for the manipulation of the sensory attributes, and thus improvement of the sensory properties of the fortified food. However, iron fortification programs have not systematically measured the effect of fortification on the sensory quality of the food. Because sensory evaluation is an important criterion in successful iron fortification, an integrated approach is necessary. Therefore, nutritionists and sensory scientists should work closely with each other to select the most suitable sensory tests and methods. The objectives of this article are to: (1) critically review and discuss some traditional and contemporary approaches and applications of sensory evaluation practices in iron fortification programs, and (2) demonstrate the importance of incorporating a multidisciplinary, systematic sensory evaluation approach in iron fortification programs.

  1. [Biochemical markers of iron status].

    PubMed

    Aimone-Gastin, Isabelle

    2006-11-01

    Traditionally, the standard biochemical markers of iron status are serum iron, transferrin, transferrin saturation, ferritin and, more recently, soluble transferrin receptor. Diagnosis of iron deficiency is usually associated with a low serum ferritin concentration. The diagnosis can be difficult in diseases in which there is an acute-phase response, because ferritin is an acute-phase reactant. In this case, measuring soluble transferrin receptor may be useful because an increased concentration is an indicator of iron deficiency. Iron stores are frequently diminished in patients on dialysis, as a result of increased blood loss and poor iron absorption. Demand for available iron is increased further by the use of erythropoietin and iron deficiency is one of the primary causes for decreased response to recombinant human erythropoeitin therapy (rHuEpo). Prevalence of inflammation in patients on dialysis is estimated to be high (as 50% patients). Because ferritin is an acute-phase reactant, levels may be elevated in cases of inflammation. The aim of recent guidelines is to better assess anaemia and iron stores. Serum ferritin and transferrin saturation are regarded as the most reliable indicators of iron status. A newer alternative laboratory measurement is the soluble transferrin receptor. Some authors suggest that the circulating soluble transferring receptor levels may be useful in monitoring iron status in patients on dialysis if rHuEpo doses are maintained constant. Prospective longitudinal studies are needed to evaluate this hypothesis. PMID:17373277

  2. Degradation of chlorofluorocarbons using granular iron and bimetallic irons

    NASA Astrophysics Data System (ADS)

    Jeen, Sung-Wook; Lazar, Snezana; Gui, Lai; Gillham, Robert W.

    2014-03-01

    Degradation of trichlorofluoromethane (CFC11) and 1,1,2-trichloro-1,2,2-trifluoroethane (CFC113) by granular iron and bimetallic (nickel- or palladium-enhanced) irons was studied in flow-through column tests. Both compounds were rapidly degraded, following pseudo-first-order kinetics with respect to the parent compounds. The average pseudo-first-order rate constants for CFC11 were similar among different materials, except for palladium-enhanced iron (PdFe), in which the rate of degradation was about two times faster than for the other materials. In the case of CFC113, the rate constants for bimetallic irons were about two to three times greater than for the regular iron material. The smaller than expected differences in degradation rate constants of chlorofluorocarbons (CFCs) between regular iron and bimetallic irons suggested little, if any, catalytic effect of the bimetallic materials in the initial degradation step. Subsequent degradation steps involved catalytic hydrogenation, however, playing a significant role in further degradation of reaction intermediates. The degradation intermediates and final products of CFC11 and CFC113 suggested that degradation proceeded through hydrogenolysis and ?/?-elimination in the presence of regular iron (Fe) and nickel-enhanced iron (NiFe). Even though there is only minor benefit in the use of bimetallic iron in terms of degradation kinetics of the parent CFCs, enhanced degradation rates of intermediates such as chlorotriflouroethene (CTFE) in subsequent reaction steps could be beneficial.

  3. Protein-Protein Interactions of the Human Iron Sulfur Cluster Biosynthesis Complex 

    E-print Network

    Levy, Michaella J

    2014-06-05

    Iron sulfur (Fe-S) clusters are integral cofactors responsible for a number of cellular processes including electron transfer, catalyzing substrate turnover, sensing small molecules, and regulating gene expression or enzymatic activity. Elaborate...

  4. Iron metabolism in aerobes: managing ferric iron hydrolysis and ferrous iron autoxidation

    PubMed Central

    Kosman, Daniel J.

    2012-01-01

    Aerobes and anaerobes alike express a plethora of essential iron enzymes; in the resting state, the iron atom(s) in these proteins are in the ferrous state. For aerobes, ferric iron is the predominant environmental valence form which, given ferric iron’s aqueous chemistry, occurs as ‘rust’, insoluble, bio-inert polymeric ferric oxide that results from the hydrolysis of [Fe(H2O)6]3+. Mobilizing this iron requires bio-ferrireduction which in turn requires managing the rapid autoxidation of the resulting FeII which occurs at pH > 6. This review examines the aqueous redox chemistry of iron and the mechanisms evolved in aerobes to suppress the ‘rusting out’ of FeIII and the ROS-generating autoxidation of FeII so as to make this metal ion available as the most ubiquitous prosthetic group in metallobiology. PMID:23264695

  5. Iron pages of HTSC

    SciTech Connect

    Gasparov, V. A., E-mail: vgasparo@issp.ac.r [Russian Academy of Sciences, Institute of Solid State Physics (Russian Federation)

    2010-08-15

    Experimental data are presented on the superconducting and electronic properties of iron-based high-temperature superconductors in the normal and superconducting states. The following topics are discussed: lattice structure; structure of magnetic vortices; magnetic penetration depth; Fermi surface; isotope effect; and critical magnetic fields both in oxide compounds of 1111 type and oxide-free compounds of 122, 111, and 011 types as a function of the doping level, temperature, and external pressure.

  6. Iron homeostasis and eye disease

    PubMed Central

    Loh, Allison; Hadziahmetovic, Majda; Dunaief, Joshua L.

    2009-01-01

    Summary Iron is necessary for life, but excess iron can be toxic to tissues. Iron is thought to damage tissues primarily by generating oxygen free radicals through the Fenton reaction. We present an overview of the evidence supporting iron's potential contribution to a broad range of eye disease using an anatomical approach. Firstly, iron can be visualized in the cornea as iron lines in the normal aging cornea as well as in diseases like keratoconus and pterygium. In the lens, we present the evidence for the role of oxidative damage in cataractogenesis. Also, we review the evidence that iron may play a role in the pathogenesis of the retinal disease age-related macular degeneration. Although currently there is no direct link between excess iron and development of optic neuropathies, ferrous iron's ability to form highly reactive oxygen species may play a role in optic nerve pathology. Lastly, we discuss recent advances in prevention and therapeutics for eye disease with antioxidants and iron chelators,. PMID:19059309

  7. Ultrastructural cytochemistry of iron absorption.

    PubMed Central

    Parmley, R. T.; Barton, J. C.; Conrad, M. E.; Austin, R. L.

    1978-01-01

    Conventional ultrastructural autoradiographic and morphologic studies of the duodenal mucosal cell have generally corroborated physiologic observations of iron absorption, but such methods have limited resolution and fail to distinguish ferric and ferrous iron. This study describes the application of the Prussian blue reaction as an electron microscopic cytochemical stain to the investigation of inorganic iron absorption in iron-deficient, normal, and iron-loaded rats. Ferrous iron is converted to ferric iron at the microvillus membrane. Subsequently intraepithelial ferric iron appears bound to a non-heme acceptor substance in microvilli and later appears as small non-membrane-bound stain deposits which are concentrated in the apical cytoplasm. The appearance of larger stain deposits in the lateral intercellular spaces, in the basal extracellular spaces, and along the intraluminal and extraluminal outer plasmalemma of adjacent endothelial cells of the lamina propria suggests passage of iron from epithelial cells through the lamina propria to blood vessels. The extreme sensitivity of the method compared with simultaneous ultrastructural autoradiographic techniques is demonstrated and suggests usefulness of the method in further studies of iron metabolism. Images Figure 3 Figures 4-5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 1 Figure 2 PMID:717544

  8. Flare Plasma Iron Abundance

    NASA Technical Reports Server (NTRS)

    Dennis, Brian R.; Dan, Chau; Jain, Rajmal; Schwartz, Richard A.; Tolbert, Anne K.

    2008-01-01

    The equivalent width of the iron-line complex at 6.7 keV seen in flare X-ray spectra suggests that the iron abundance of the hottest plasma at temperatures >approx.10 MK may sometimes be significantly lower than the nominal coronal abundance of four times the photospheric value that is commonly assumed. This conclusion is based on X-ray spectral observations of several flares seen in common with the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and the Solar X-ray Spectrometer (SOXS) on the second Indian geostationary satellite, GSAT-2. The implications of this will be discussed as it relates to the origin of the hot flare plasma - either plasma already in the corona that is directly heated during the flare energy release process or chromospheric plasma that is heated by flare-accelerated particles and driven up into the corona. Other possible explanations of lower-than-expected equivalent widths of the iron-line complex will also be discussed.

  9. The Iron-Tower Manufacture Enterprise Oriented PDM System Design

    Microsoft Academic Search

    Tang Changping; Hua Zhongping

    2009-01-01

    Specify for the characteristics of simple manufacture processes and information flows in iron tower manufacturing industry. Based on an analysis of the problems exist in information resource management for an enterprise. This project introduced the advanced management ideas; rebuilt the project management system in the enterprise; integrated with the process of information of design, technics, manufacturing, materials, and so on.

  10. Thermal imaging of railroad cars used for molten iron transport

    Microsoft Academic Search

    Christopher A. Sahr

    1999-01-01

    The primary production of steel in integrated mills commonly uses Pugh-type railroad cars to transport molten iron from the Blast Furnace process to the Basic Oxygen Furnace Process. Thermal imaging and analysis can be used to monitor the condition of the refractory within these railroad cars. This results in the avoidance of molten metal breakouts on the cars and the

  11. Blood withdrawal affects iron store dynamics in primates with consequences on monoaminergic system function.

    PubMed

    Hyacinthe, C; De Deurwaerdere, P; Thiollier, T; Li, Q; Bezard, E; Ghorayeb, I

    2015-04-01

    Iron homeostasis is essential for the integrity of brain monoaminergic functions and its deregulation might be involved in neurological movement disorders such as the restless legs syndrome (RLS). Although iron metabolism breakdown concomitantly appears with monoaminergic system dysfunction in iron-deficient rodents and in RLS patients, the direct consequences of peripheral iron deficiency in the central nervous system (CNS) of non-human primates have received little attention. Here, we evaluated the peripheral iron-depletion impact on brain monoamine levels in macaque monkeys. After documenting circadian variations of iron and iron-related proteins (hemoglobin, ferritin and transferrin) in both serum and cerebrospinal fluid (CSF) of normal macaques, repeated blood withdrawals (RBW) were used to reduce peripheral iron-related parameter levels. Decreased serum iron levels were paradoxically associated with increased CSF iron concentrations. Despite limited consequences on tissue monoamine contents (dopamine - DA, 3, 4-dihydroxyphenylacetic acid - DOPAC, homovanillic acid, L-3, 4-dihydroxyphenylalanine - L-DOPA, 5-8 hydroxytryptamine - 5-HT, 5-hydroxyindoleacetic acid - 5-HIAA and noradrenaline) measured with post-mortem chromatography, we found distinct and region-dependent relationships of these tissue concentrations with CSF iron and/or serum iron and/or blood hemoglobin. Additionally, striatal extracellular DA, DOPAC and 5-HIAA levels evaluated by in vivo microdialysis showed a substantial increase, suggesting an overall increase in both DA and 5-HT tones. Finally, a trending increase in general locomotor activity, measured by actimetry, was observed in the most serum iron-depleted macaques. Taken together, our data are compatible with an increase in nigrostriatal DAergic function in the event of iron deficiency and point to a specific alteration of the 5-HT/DA interaction in the CNS that is possibly involved in the etiology of RLS. PMID:25662508

  12. Interference of deferasirox with assays for serum iron and serum unsaturated iron binding capacity during iron chelating therapy

    Microsoft Academic Search

    Katsuya Ikuta; Satoshi Ito; Hiroki Tanaka; Katsunori Sasaki; Yoshihiro Torimoto; Mikihiro Fujiya; Yutaka Kohgo

    2011-01-01

    BackgroundDeferasirox (DFX) is an oral iron chelator that is used worldwide for the treatment of iron overload. Although serum ferritin level is usually measured as a marker of the efficacy of DFX, we sometimes experienced unexplainable changes in other serum markers for iron. We hypothesized that photometric assays for serum iron (sFe) and unsaturated iron binding capacity (UIBC) might be

  13. Extracellular Iron Biomineralization by Photoautotrophic Iron-Oxidizing Bacteria

    Microsoft Academic Search

    Jennyfer Miot; Karim Benzerara; Martin Obst; Andreas Kappler; Florian Hegler; Sebastian Schadler; Camille Bouchez; Francois Guyot; Guillaume Morin

    2009-01-01

    Iron oxidation at neutral pH by the phototrophic anaerobic iron-oxidizing bacterium Rhodobacter sp. strain SW2 leads to the formation of iron-rich minerals. These minerals consist mainly of nano-goethite (-FeOOH), which precipitates exclusively outside cells, mostly on polymer fibers emerging from the cells. Scanning transmission X-ray microscopy analyses performed at the C K-edge suggest that these fibers are composed of a

  14. Mother's iron status, breastmilk iron and lactoferrin – are they related?

    Microsoft Academic Search

    Shashiraj; M M A Faridi; O Singh; U Rusia; MMA Faridi

    2006-01-01

    Objective:Exclusive breastfeeding is recommended till 6 months age. Factors regulating the breastmilk iron and lactoferrin levels are incompletely known. Considering high prevalence of nutritional anemia in lactating mothers, we studied the iron status of lactating mothers, their breastmilk iron and lactoferrin levels to determine any relationship between them.Design:Prospective study with 6 months follow-up.Setting:Tertiary care referral hospital.Subjects:Hundred nonanemic and 100 anemic

  15. Iron and Immunity: Immunological Consequences of Iron Deficiency and Overload

    Microsoft Academic Search

    Bobby J. Cherayil

    2010-01-01

    The influence of iron on immune function has been long appreciated. However, the molecular basis for this interaction is less\\u000a well understood. Recently, there have been several important advances that have shed light on the mechanisms that regulate\\u000a mammalian iron metabolism. The new insights provide a conceptual framework for understanding and manipulating the cross-talk\\u000a between iron homeostasis and the immune

  16. Biologically induced iron ore at Gunma iron mine, Japan

    Microsoft Academic Search

    JUNJI AKAI; KURUMI AKAI; MAKOTO ITO; SATOSHI NAKANO; YONOSUKE MAKI; ICHIRO SASAGAWA

    1999-01-01

    The mineralogy of sedimentary iron ores from the Gunma iron mine are described to evaluate the role of microorganisms and plants in ore formation. The iron ore is composed of nanocrystalline goethite, well-crystallized jarosite and very small amounts of strengite. The ore characteristically occurs as thick-bands of alternating goethite and jarosite bands, thin-bands of different goethite grain sizes, and fossil-aggregate

  17. Iron Metabolism, Iron Deficiency, Thrombocytosis, and the Cardiorenal Anemia Syndrome

    Microsoft Academic Search

    ANATOLE BESARAB; WALTER HERMANN HÖRL

    Intreatingmoderatetosevereanemiaofchronickidney disease(CKD),oralironiseffectiveonlyinaminorityof nondialysis patients. Intravenous iron is more effective and can raise levels of hemoglobin even without the use of erythropoiesis-stimulating agents (ESAs). Unfortu- nately, the current assays of iron status that are pres- ently widely available are not especially helpful in predicting response. In patients on dialysis, i.v. iron is effective over a wide range of serum ferritin from

  18. Deciphering Fur transcriptional regulatory network highlights its complex role beyond iron metabolism in Escherichia coli.

    PubMed

    Seo, Sang Woo; Kim, Donghyuk; Latif, Haythem; O'Brien, Edward J; Szubin, Richard; Palsson, Bernhard O

    2014-01-01

    The ferric uptake regulator (Fur) plays a critical role in the transcriptional regulation of iron metabolism. However, the full regulatory potential of Fur remains undefined. Here we comprehensively reconstruct the Fur transcriptional regulatory network in Escherichia coli K-12 MG1655 in response to iron availability using genome-wide measurements. Integrative data analysis reveals that a total of 81 genes in 42 transcription units are directly regulated by three different modes of Fur regulation, including apo- and holo-Fur activation and holo-Fur repression. We show that Fur connects iron transport and utilization enzymes with negative-feedback loop pairs for iron homeostasis. In addition, direct involvement of Fur in the regulation of DNA synthesis, energy metabolism and biofilm development is found. These results show how Fur exhibits a comprehensive regulatory role affecting many fundamental cellular processes linked to iron metabolism in order to coordinate the overall response of E. coli to iron availability. PMID:25222563

  19. The iron chelator deferasirox protects mice from mucormycosis through iron starvation

    PubMed Central

    Ibrahim, Ashraf S.; Gebermariam, Teclegiorgis; Fu, Yue; Lin,, Lin; Husseiny, Mohamed I.; French, Samuel W.; Schwartz, Julie; Skory, Christopher D.; Edwards, John E.; Spellberg, Brad J.

    2007-01-01

    Mucormycosis causes mortality in at least 50% of cases despite current first-line therapies. Clinical and animal data indicate that the presence of elevated available serum iron predisposes the host to mucormycosis. Here we demonstrate that deferasirox, an iron chelator recently approved for use in humans by the US FDA, is a highly effective treatment for mucormycosis. Deferasirox effectively chelated iron from Rhizopus oryzae and demonstrated cidal activity in vitro against 28 of 29 clinical isolates of Mucorales at concentrations well below clinically achievable serum levels. When administered to diabetic ketoacidotic or neutropenic mice with mucormycosis, deferasirox significantly improved survival and decreased tissue fungal burden, with an efficacy similar to that of liposomal amphotericin B. Deferasirox treatment also enhanced the host inflammatory response to mucormycosis. Most importantly, deferasirox synergistically improved survival and reduced tissue fungal burden when combined with liposomal amphotericin B. These data support clinical investigation of adjunctive deferasirox therapy to improve the poor outcomes of mucormycosis with current therapy. As iron availability is integral to the pathogenesis of other infections (e.g., tuberculosis, malaria), broader investigation of deferasirox as an antiinfective treatment is warranted. PMID:17786247

  20. Iron isotopes constrain biologic and abiologic processes in banded iron formation genesis

    E-print Network

    Roden, Eric E.

    Iron isotopes constrain biologic and abiologic processes in banded iron formation genesis Clark M banded iron formations (BIFs) from the Hamersley Basin (Australia) and Transvaal Craton (South Africa, (2) complete reduction by bacterial dissimilatory iron reduction (DIR), and (3) interaction

  1. 49 CFR 192.369 - Service lines: Connections to cast iron or ductile iron mains.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Service lines: Connections to cast iron or ductile iron mains. 192.369 Section 192.369 Transportation... § 192.369 Service lines: Connections to cast iron or ductile iron mains. (a) Each service line...

  2. Intestinal Iron Homeostasis and Colon Tumorigenesis

    PubMed Central

    Xue, Xiang; Shah, Yatrik M.

    2013-01-01

    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. PMID:23812305

  3. Microbial reduction of iron ore

    DOEpatents

    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.

  4. Microbial reduction of iron ore

    DOEpatents

    Hoffmann, Michael R. (Pasadena, CA); Arnold, Robert G. (Pasadena, CA); Stephanopoulos, Gregory (Pasadena, CA)

    1989-01-01

    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.

  5. Intravenous Iron Sucrose and Oral Iron for the Treatment of Iron Deficiency Anaemia in Pregnancy

    PubMed Central

    Abhilashini, G.D.; Reddi, Rani

    2014-01-01

    Purpose: The aim of this study was to compare the efficacy and safety of intravenous iron sucrose and oral iron administration for the treatment of iron deficiency anaemia in pregnancy. Materials and Methods: Hundred women with gestational age between 30 and 34 weeks with established iron deficiency anaemia with Haemoglobin-6-8g/dL were randomised to receive either oral ferrous sulphate 200 mg thrice daily or required dose of intravenous iron sucrose 200 mg in 200 ml NS on alternate days. Haemoglobin, haematocrit, mean corpuscular volume, reticulocyte count were measured at recruitment and on 2nd week, 4th week and at 37 weeks. Adverse drug reactions were also noted in both the groups. Results were analyzed by student’s t-test and Chi-square test. Results: Haemoglobin values varied significantly with time between the two groups at second week, 4th week and at term (p<0.005). The mean difference in mean corpuscular volume from the recruitment value was not significant at 2nd week. When compared to iron sucrose group, oral iron group had significant gastro-intestinal adverse effects. Conclusion: Intravenous iron sucrose treated iron deficiency anaemia of pregnancy faster, and more effectively than oral iron therapy, with no serious adverse drug reactions. PMID:24995217

  6. Alterations of iron distribution in Arabidopsis tissues infected by Dickeya dadantii.

    PubMed

    Aznar, Aude; Patrit, Oriane; Berger, Adeline; Dellagi, Alia

    2015-06-01

    Dickeya dadantii is a plant-pathogenic enterobacterium responsible for plant soft rot disease in a wide range of hosts, including the model plant Arabidopsis thaliana. Iron distribution in infected A.?thaliana was investigated at the cellular scale using the Perls'-diaminobenzidine-H2 O2 (PDH) method. Iron visualization during infection reveals a loss of iron from cellular compartments and plant cell walls. During symptom progression, two distinct zones are clearly visible: a macerated zone displaying weak iron content and a healthy zone displaying strong iron content. Immunolabelling of cell wall methylated pectin shows that pectin degradation is correlated with iron release from cell walls, indicating a strong relationship between cell wall integrity and iron in plant tissues. Using a D.?dadantii lipopolysaccharide antibody, we show that bacteria are restricted to the infected tissue, and that they accumulate iron in?planta. In conclusion, weak iron content is strictly correlated with bacterial cell localization in the infected tissues, indicating a crucial role of this element during the interaction. This is the first report of iron localization at the cellular level during a plant-microbe interaction and shows that PDH is a method of choice in this type of investigation. PMID:25266463

  7. Iron, brain and restless legs syndrome

    Microsoft Academic Search

    Jean Krieger; Carmen Schroeder

    2001-01-01

    Iron is the most important transitional metal in the body, as it is implicated in many metabolic processes, mostly related to its capacity as an electron donor\\/acceptor. Iron deficiency has been long been known to cause anaemia, iron excess to cause haemochromatosis. As excess free iron can cause oxidative damage, it is important that the levels of iron in the

  8. The history of iron in the brain

    Microsoft Academic Search

    Arnulf H. Koeppen

    1995-01-01

    Brain iron research began in the late nineteenth century when Zaleski (1886) made a quantitative analysis of one human brain and correlated iron levels with observations on stained slices and some microscopic sections. Gradually, the realization grew that the central nervous system (CNS) contained iron which was different from hemoglobin-iron. This non-heme iron was found in highest concentrations in globus

  9. Cellular management of iron in the brain

    Microsoft Academic Search

    James R. Connor; Sharon L. Menzies

    1995-01-01

    All organs including the brain contain iron, and the proteins involved in iron uptake (transferrin and transferrin receptor) and intracellular storage (ferritin). However, because the brain resides behind a barrier and has a heterogeneous population of cells, there are aspects of its iron management that are unique. Iron management, the timely delivery of appropriate amounts of iron, is crucial to

  10. Iron supplementation of breastfed infants.

    PubMed

    Ziegler, Ekhard E; Nelson, Steven E; Jeter, Janice M

    2011-11-01

    Reported here are three studies performed with the objective of finding ways to improve the iron status of breastfed infants and to prevent iron deficiency (ID). Participating infants were exclusively breastfed until 4 months of age; thereafter, they could receive complementary foods and, in some studies, supplemental formula. In the first study, infants were given medicinal iron between the ages of 1 and 5.5 months. During this period, iron status improved and ID was prevented; however, these benefits did not continue after the intervention ceased. In the second study, infants received medicinal iron or an equivalent amount of iron from an iron-fortified cereal between the ages of 4 and 9 months. Again, iron supplementation largely prevented ID from occurring, while non-anemic ID and ID anemia occurred in the control group as well as in the intervention groups before the intervention began. In the third study, infants received dry cereals fortified with electrolytic iron or with ferrous fumarate between the ages of 4 and 9 months. The cereals were equally effective in providing relative protection from ID. The results of these three studies indicate it is possible to protect breastfed infants from ID and IDA. PMID:22043886

  11. Good Sources of Nutrients: Iron 

    E-print Network

    Scott, Amanda; Replogle, Jacqueline

    2008-08-28

    aprender Hierro para la salud Reduce el riesgo de anemia por deficiencia de ? hierro Puede ayudar a evitar infecciones? ?D?nde se encuentra el hierro? El hierro es un mineral que se encuentra en una var- iedad de alimentos, tal como: Carne magra? Panes y... health Reduces the risk of iron-deficiency anemia? May help prevent infections? Where is iron found? Iron is a mineral found in a variety of foods such as: Lean meat? Iron-enriched and whole-grain breads and ? cereals Cooked dried beans including...

  12. Placing Iron on Test Plate 

    E-print Network

    Unknown

    2011-08-17

    Selection of Solvents Ex+rect, ion of Iron 17 D. 'TERMINATION OE IRON 2j Selection o+' An" lytic, I Parameters 1'reparation of' Working Curves y4 DETERMINATION Ol" NICKEL DISCUSSION . Experimental Proc cdur c k6 4o Res ults 5O Recommended Ar a1y.... Arrangemerzt oi' burner and sample during analysis. Page 15 2. Absorbances of extracts of 0. 1 ppm iron at various pH's with solutions of 0. 2p 8-hydroxyquinoline in methyl zsobutyl ketone. 1. 8 Absorbsnces of extracts of 0. 1 ppm iron at various p...

  13. The effect of different iron fortificants on iron absorption from iron-fortified rice.

    PubMed

    Trinidad, Trinidad Palad; Valdez, Divinagracia Halili; Mallillin, Aida Casibang; Askali, Faridah Chua; Dara-ug, Allan Francis; Capanzana, Mario Villasaya

    2002-09-01

    Iron absorption from rice fortified with different iron fortificants, e.g., ferrous sulfate (FeS04), sodium iron EDTA (NaFeEDTA), ferrous fumarate (FeFum), and ferrous bisglycinate (FeBis) was determined using an in vitro enzymatic digestion method simulating conditions in the small intestine and an in vivo method using radioisotope techniques. The in vitro method showed that the percentage of dialyzable iron from NaFeEDTA (15.7 +/- 0.9) and FeS04-fortified rice (13.2 +/- 1.5) was significantly greater than that from FeFum (6.4 +/- 0.6; p < .05) and FeBis fortified rice (3.3 +/- 0.8; p < .05). Iron absorption in vivo was investigated from FeS04 and NaFeEDTA fortified rice with and without fish and vegetables in 10 borderline iron-deficient subjects. Iron absorption (mg) from NaFeEDTA fortified rice (0.44 +/- 0.11) was significantly greater than from FeS04-fortified rice (0.22 +/- 0.05; p < .05) and the unfortified rice (0.17 +/- 0.02; p < .05). Iron absorption (mg) from a meal consisting of iron-fortified rice, fish, and vegetables was significantly greater from NaFeEDTA (0.88 +/- 0.24) and FeS04 (0.67 +/- 0.10) -fortified rice than from the unfortified rice (0.41 +/- 0.08; p < .05). This study concluded that both NaFeEDTA and FeSO4 are effective iron fortificants for rice. The binder used in the study may have a significant role in the release of iron from iron-fortified rice for absorption. Further studies on the use of other binders to maximize iron release and minimize iron loss during cooking should be conducted to improve iron absorption from the fortified rice/rice-fish-vegetable meals. Results from this study can be used as a basis for food iron fortification programs as well as in the establishment of recommended dietary allowances for iron among Filipinos. PMID:12362796

  14. IRON RELEASE AND COLORED WATER FORMATION FROM IRON SCALES

    EPA Science Inventory

    Iron corrosion in water distribution networks is of special concern in the drinking water industry because of the large amount of unlined iron pipe that is in use. Corrosion can destroy the pipe, consume oxidants and disinfectants in the water, create scales that increase the en...

  15. MALLEABLE IRON BULL LADLE, HOLDS IRON AFTER IT IS TAPPED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    MALLEABLE IRON BULL LADLE, HOLDS IRON AFTER IT IS TAPPED OUT OF THE CUPOLA UNTIL IT NEEDED BY POURERS ON THE CONVEYOR LINES WHO FILL MOBILE LADLES ATTACHED TO OVERHEAD RAIL SYSTEMS AS THE BULL LADLE TIPS. - Stockham Pipe & Fittings Company, Malleable Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  16. Studies of hypervalent iron

    SciTech Connect

    Bielski, B.H.J.

    1989-01-01

    The iron (IV), (V) and (VI) oxidation states are of great interest because of their role in catalytic oxidation/hydroxylation reactions. This report summarizes the information currently available on the kinetic and chemical properties of the water-soluble ions of FeO{sub 4}{sup 2{minus}}, FeO{sub 4}{sup 3{minus}} and FeO{sub 4}{sup 4{minus}}, their protonated forms, and/or simple complex derivatives. The discussion includes their radiation-induced formation, decay kinetics, reactivity with other compounds, determination of their respective pK{sub a} values as well as spectral properties. 32 refs., 3 figs., 2 tabs.

  17. Snapshot of iron response in Shewanella oneidensis by gene network reconstruction

    SciTech Connect

    Yang, Yunfeng; Harris, Daniel P.; Luo, Feng; Xiong, Wenlu; Joachimiak, Marcin; Wu, Liyou; Dehal, Paramvir; Jacobsen, Janet; Yang, Zamin; Palumbo, Anthony V.; Arkin, Adam P.; Zhou, Jizhong

    2008-10-09

    Background: Iron homeostasis of Shewanella oneidensis, a gamma-proteobacterium possessing high iron content, is regulated by a global transcription factor Fur. However, knowledge is incomplete about other biological pathways that respond to changes in iron concentration, as well as details of the responses. In this work, we integrate physiological, transcriptomics and genetic approaches to delineate the iron response of S. oneidensis. Results: We show that the iron response in S. oneidensis is a rapid process. Temporal gene expression profiles were examined for iron depletion and repletion, and a gene co-expression network was reconstructed. Modules of iron acquisition systems, anaerobic energy metabolism and protein degradation were the most noteworthy in the gene network. Bioinformatics analyses suggested that genes in each of the modules might be regulated by DNA-binding proteins Fur, CRP and RpoH, respectively. Closer inspection of these modules revealed a transcriptional regulator (SO2426) involved in iron acquisition and ten transcriptional factors involved in anaerobic energy metabolism. Selected genes in the network were analyzed by genetic studies. Disruption of genes encoding a putative alcaligin biosynthesis protein (SO3032) and a gene previously implicated in protein degradation (SO2017) led to severe growth deficiency under iron depletion conditions. Disruption of a novel transcriptional factor (SO1415) caused deficiency in both anaerobic iron reduction and growth with thiosulfate or TMAO as an electronic acceptor, suggesting that SO1415 is required for specific branches of anaerobic energy metabolism pathways. Conclusions: Using a reconstructed gene network, we identified major biological pathways that were differentially expressed during iron depletion and repletion. Genetic studies not only demonstrated the importance of iron acquisition and protein degradation for iron depletion, but also characterized a novel transcriptional factor (SO1415) with a role in anaerobic energy metabolism.

  18. The Iron Metallome in Eukaryotic Organisms

    PubMed Central

    Dlouhy, Adrienne C.; Outten, Caryn E.

    2013-01-01

    This chapter is focused on the iron metallome in eukaryotes at the cellular and subcellular level, including properties, utilization in metalloproteins, trafficking, storage, and regulation of these processes. Studies in the model eukaryote Saccharomyces cerevisiae and mammalian cells will be highlighted. The discussion of iron properties will center on the speciation and localization of intracellular iron as well as the cellular and molecular mechanisms for coping with both low iron bioavailability and iron toxicity. The section on iron metalloproteins will emphasize heme, iron-sulfur cluster, and non-heme iron centers, particularly their cellular roles and mechanisms of assembly. The section on iron uptake, trafficking, and storage will compare methods used by yeast and mammalian cells to import iron, how this iron is brought into various organelles, and types of iron storage proteins. Regulation of these processes will be compared between yeast and mammalian cells at the transcriptional, post-transcriptional, and post-translational levels. PMID:23595675

  19. 21 CFR 73.3125 - Iron oxides.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Iron oxides. 73.3125 Section 73.3125...CERTIFICATION Medical Devices § 73.3125 Iron oxides. (a) Identity and specifications. The color additive iron oxides (CAS Reg. No....

  20. 49 CFR 230.91 - Chafing irons.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 2014-10-01 false Chafing irons. 230.91 Section 230.91 Transportation ...Draw Gear and Draft Systems § 230.91 Chafing irons. Chafing irons that permit proper curving shall be securely...

  1. 49 CFR 230.91 - Chafing irons.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2013-10-01 2013-10-01 false Chafing irons. 230.91 Section 230.91 Transportation ...Draw Gear and Draft Systems § 230.91 Chafing irons. Chafing irons that permit proper curving shall be securely...

  2. 21 CFR 73.3125 - Iron oxides.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Iron oxides. 73.3125 Section 73.3125...CERTIFICATION Medical Devices § 73.3125 Iron oxides. (a) Identity and specifications. The color additive iron oxides (CAS Reg. No....

  3. 21 CFR 73.3125 - Iron oxides.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Iron oxides. 73.3125 Section 73.3125...CERTIFICATION Medical Devices § 73.3125 Iron oxides. (a) Identity and specifications. The color additive iron oxides (CAS Reg. No....

  4. 49 CFR 230.91 - Chafing irons.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 2012-10-01 2012-10-01 false Chafing irons. 230.91 Section 230.91 Transportation ...Draw Gear and Draft Systems § 230.91 Chafing irons. Chafing irons that permit proper curving shall be securely...

  5. 49 CFR 230.91 - Chafing irons.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 2010-10-01 2010-10-01 false Chafing irons. 230.91 Section 230.91 Transportation ...Draw Gear and Draft Systems § 230.91 Chafing irons. Chafing irons that permit proper curving shall be securely...

  6. 21 CFR 73.3125 - Iron oxides.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Iron oxides. 73.3125 Section 73.3125...CERTIFICATION Medical Devices § 73.3125 Iron oxides. (a) Identity and specifications. The color additive iron oxides (CAS Reg. No....

  7. 49 CFR 230.91 - Chafing irons.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 2011-10-01 2011-10-01 false Chafing irons. 230.91 Section 230.91 Transportation ...Draw Gear and Draft Systems § 230.91 Chafing irons. Chafing irons that permit proper curving shall be securely...

  8. Iron piracy: acquisition of transferrin-bound iron by bacterial pathogens.

    PubMed

    Cornelissen, C N; Sparling, P F

    1994-12-01

    The mechanism of iron utilization from transferrin has been most extensively characterized in the pathogenic Neisseria species and Haemophilus species. Two transferrin-binding proteins, Tbp1 and Tbp2, have been identified in these pathogens and are thought to be components of the transferrin receptor. Tbp1 appears to be an integral, TonB-dependent outer membrane protein while Tbp2, a lipoprotein, may be peripherally associated with the outer membrane. The relative contribution of each of these proteins to transferrin binding and utilization is discussed and a model of iron uptake from transferrin is presented. Sequence comparisons of the genes encoding neisserial transferrin-binding proteins suggest that they are probably under positive selection for variation and may have resulted from inter-species genetic exchange. PMID:7715446

  9. Iron in yeast: Mechanisms involved in homeostasis

    Microsoft Academic Search

    Ernest Kwok; Daniel Kosman

    Iron homeostasis results from matching iron uptake to cell growth and division in the context of the overall cell requirement\\u000a for iron. Fungi achieve this balance by transcriptional regulation of the genes that encode iron uptake activities; post-transcriptional\\u000a regulation of the synthesis of proteins that use iron; and storage and recycling of iron to meet short-term needs in times\\u000a of

  10. Molecular liaisons between erythropoiesis and iron metabolism

    PubMed Central

    Kautz, Leon

    2014-01-01

    Although most circulating iron in blood plasma is destined for erythropoiesis, the mechanisms by which erythropoietic demand modulates the iron supply (“erythroid regulators”) remain largely unknown. Iron absorption, plasma iron concentrations, and tissue iron distribution are tightly controlled by the liver-produced hormone hepcidin. During the last decade, much progress has been made in elucidating hepcidin regulation by iron and inflammation. This review discusses the less understood mechanisms and mediators of hepcidin suppression in physiologically and pathologically stimulated erythropoiesis. PMID:24876565

  11. Complementary Vibrational Spectroscopy Investigations of Iron and Iron-Bearing Minerals (Invited)

    NASA Astrophysics Data System (ADS)

    Murphy, C. A.; Antonangeli, D.; Fiquet, G.; Fei, Y.; Alatas, A.; Dera, P. K.

    2011-12-01

    The high-pressure elastic and thermodynamic properties of iron have been extensively studied because iron is thought to be the main constituent in Earth's core, along with ~5 to 10 wt% nickel and some light elements. In particular, nuclear resonant inelastic x-ray scattering (NRIXS) is an isotope-selective technique that has been used to investigate the vibrational properties of 57Fe at high-pressure via its measured phonon density of states (DOS) [e.g., 1]. For example, the low-energy region of a material's phonon DOS is proportional to its Debye sound velocity (vD), which reflects an average of its compressional (vP) and shear (vS) sound velocities, weighted more heavily towards vS [2]. In order to separate the compressional and shear components of vD, one often relies on established equations of state (EOS) which, in the case of iron, diverge above 100 GPa [e.g., 3; 4]. In turn, such uncertainties are propagated into iron's sound velocities--particularly vP--at pressures approaching those of Earth's core. Here we demonstrate how the combination of NRIXS and high-energy resolution inelastic x-ray scattering (HERIX) data allows for the determination of both vP and vS, independent of an EOS. In particular, we used NRIXS and HERIX to probe the total phonon DOS and points along the longitudinal acoustic phonon branch, respectively, of pure iron loaded into similarly prepared diamond anvil cells, up to a pressure of 171 GPa at 300 K [1; 5]. Experiments were performed at the Advanced Photon Source and European Synchrotron Radiation Facility, where sample volumes (densities) were also measured with in-situ x-ray diffraction. Using established NRIXS and HERIX fitting procedures, we determined iron's density-dependent vD and vP, respectively, accounting for mass effects in the former parameter using a harmonic oscillator model. The combination of these datasets [1; 5] provides a new tight constraint on the density-dependent compressional and shear sound velocities of iron, independent of an EOS. In light of these new findings, we will discuss specific implications for Earth's core, and give examples of additional systems to which such a combination of techniques can be applied. Finally, in the case of pure 57Fe, the total phonon DOS is measured by NRIXS, thus providing a wealth of information about its thermodynamic properties [2]. For example, iron's mean force constant can be obtained from its integrated phonon DOS, and is related to iron's equilibrium isotopic partition function ratios (?-factors). Therefore, we will present how high-pressure NRIXS experiments can provide information about the predicted distribution of iron isotopes during equilibrium processes involving solid iron in the deep Earth [1]. References: 1. Murphy, CA, Jackson, JM, and Sturhahn, W (2013), J. Geophys. Res. Solid Earth, 118, 1999-2016, doi:10.1002/jgrb.50166. 2. Sturhahn, W, and Jackson, JM (2007), GSA Special Paper 421, 157-174, doi:10.1130/2007.2421(09). 3. Mao, HK et al. (1990), J. Geophys. Res. Solid Earth, 95, 21737-21742, doi:10.1029/JB095iB13p21737. 4. Dewaele, A et al. (2006), Phys. Rev. Lett., 97, 215504, doi:10.1103/PhysRevLett.97.215504. 5. Antonangeli, D et al. (2012), Earth Planet. Sci. Lett., 331-332, 210-214, doi:10.1016/j.epsl.2012.03.024.

  12. Clostridial Iron-Sulphur Proteins

    Microsoft Academic Search

    Jacques Meyer

    Iron-sulfur proteins are ubiquitous catalysts of a wide range of biological reactions, and are particularly abundant in clostridia which lack the ability to synthesize hemes. The development of research on these metalloproteins has therefore been strongly associated with biochemical investigations of clostridial metabolism. Major breakthroughs in the field, from the first isolation of an iron-sulfur protein in 1962, to the

  13. Iron biofortification of maize grain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mineral nutrient deficiencies are a worldwide problem that is directly correlated with poverty and food insecurity. The most common of these is iron deficiency; more than one-third of the world’s population suffers from iron deficiency-induced anemia, 80% of which are in developing countries. The co...

  14. Iron biofortification of maize grain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mineral nutrient deficiencies are a worldwide problem that is directly correlated with poverty and food insecurity. The most common of these is iron deficiency; more than one-third of the world’s population suffers from iron deficiency-induced anemia, 80% of which are in developing countries. The de...

  15. The Pharmacokinetics and Pharmacodynamics of Iron Preparations

    PubMed Central

    Geisser, Peter; Burckhardt, Susanna

    2011-01-01

    Standard approaches are not appropriate when assessing pharmacokinetics of iron supplements due to the ubiquity of endogenous iron, its compartmentalized sites of action, and the complexity of the iron metabolism. The primary site of action of iron is the erythrocyte, and, in contrast to conventional drugs, no drug-receptor interaction takes place. Notably, the process of erythropoiesis, i.e., formation of new erythrocytes, takes 3–4 weeks. Accordingly, serum iron concentration and area under the curve (AUC) are clinically irrelevant for assessing iron utilization. Iron can be administered intravenously in the form of polynuclear iron(III)-hydroxide complexes with carbohydrate ligands or orally as iron(II) (ferrous) salts or iron(III) (ferric) complexes. Several approaches have been employed to study the pharmacodynamics of iron after oral administration. Quantification of iron uptake from radiolabeled preparations by the whole body or the erythrocytes is optimal, but alternatively total iron transfer can be calculated based on known elimination rates and the intrinsic reactivity of individual preparations. Degradation kinetics, and thus the safety, of parenteral iron preparations are directly related to the molecular weight and the stability of the complex. High oral iron doses or rapid release of iron from intravenous iron preparations can saturate the iron transport system, resulting in oxidative stress with adverse clinical and subclinical consequences. Appropriate pharmacokinetics and pharmacodynamics analyses will greatly assist our understanding of the likely contribution of novel preparations to the management of anemia. PMID:24310424

  16. Mo¨ssbauer Spectra of Some Iron Complexes

    Microsoft Academic Search

    L. M. Epstein

    1962-01-01

    Mo¨ssbauer spectra were obtained for the following coordination compounds: iron phthalocyanine, ferrocene, iron carbonyl, iron III acetylacetonate, and iron II acetylacetonate dipyridine; for the following complex ion salts iron II trisphenanthroline chloride, iron III EDTA (monosodium salt), iron II EDTA, hemin, ferricium picrate, sodium nitroprusside, and some ferro- and ferricyanides.The isomer shift (relative to stainless steel) for iron II has

  17. Ironing out disease: inherited disorders of iron homeostasis.

    PubMed

    Anderson, G J

    2001-01-01

    Iron presents us with a paradox. Without it, cells simply cannot survive because iron is an essential cofactor for many enzymes in critical biochemical pathways. However, when iron is present in excess, it can be highly cytotoxic due to its propensity to catalyze the formation of reactive oxygen radicals. To cater for this dual nature, cells and organisms have developed elaborate mechanisms for regulating iron intake and efflux. When these mechanisms are disrupted, as is the case in a number of inherited disorders of iron metabolism, the pathological consequences can be severe. Many of these disorders are characterized by iron overload and include relatively common diseases such as hereditary hemochromatosis, rare abnormalities of plasma protein synthesis (atransferrinemia and aceruloplasminemia), and the neuromuscular disease Friedreich ataxia. The few described inherited anemias in humans have yet to yield to molecular dissection, but the investigation of several rodent anemias has proved highly rewarding. This review will provide a summary of some of these disorders and describe how their analysis has provided important new insights into iron trafficking pathways and their regulation. PMID:11419690

  18. Normal Iron Metabolism and the Pathophysiology of Iron Overload Disorders

    PubMed Central

    Siah, Chiang W; Ombiga, John; Adams, Leon A; Trinder, Debbie; Olynyk, John K

    2006-01-01

    Iron overload disorders represent a heterogenous group of conditions resulting from inherited and acquired causes. If undiagnosed they can be progressive and fatal. Early detection and phlebotomy prior to the onset of cirrhosis can reduce morbidity and normalise life expectancy. We now have greater insight into the complex mechanisms of normal and disordered iron homeostasis following the discovery of new proteins and genetic defects. Here we review the normal mechanisms and regulation of gastrointestinal iron absorption and liver iron transport and their dysregulation in iron overload states. Advances in the understanding of the natural history of iron overload disorders and new methods for clinical detection and management of hereditary haemochromatosis are also reviewed. The current screening strategies target high-risk groups such as first-degree relatives of affected individuals and those with clinical features suggestive of iron loading. Potential ethical, legal and psychosocial issues arising through application of genetic screening programs need to be resolved prior to implementation of general population screening programs. PMID:16886043

  19. Microbial acquisition of iron from ferric iron bearing minerals

    SciTech Connect

    Hersman, L.E. [Los Alamos National Lab., NM (United States); Sposito, G. [Univ. of California, Berkeley, CA (United States)

    1998-12-31

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Iron is a universal requirement for all life forms. Although the fourth most abundant element in the geosphere, iron is virtually insoluble at physiological pH in oxidizing environments, existing mainly as very insoluble oxides and hydroxides. Currently it is not understood how iron is solubilized and made available for biological use. This research project addressed this topic by conducting a series of experiments that utilized techniques from both soil microbiology and mineral surface geochemistry. Microbiological analysis consisted of the examination of metabolic and physiological responses to mineral iron supplements. At the same time mineral surfaces were examined for structural changes brought about by microbially mediated dissolution. The results of these experiments demonstrated that (1) bacterial siderophores were able to promote the dissolution of iron oxides, (2) that strict aerobic microorganisms may use anaerobic processes to promote iron oxide dissolution, and (3) that it is possible to image the surface of iron oxides undergoing microbial dissolution.

  20. Blockage of mitochondrial calcium uniporter prevents iron accumulation in a model of experimental subarachnoid hemorrhage.

    PubMed

    Yan, Huiying; Hao, Shuangying; Sun, Xiaoyan; Zhang, Dingding; Gao, Xin; Yu, Zhuang; Li, Kuanyu; Hang, Chun-Hua

    2015-01-24

    Previous studies have shown that iron accumulation is involved in the pathogenesis of brain injury following subarachnoid hemorrhage (SAH) and chelation of iron reduced mortality and oxidative DNA damage. We previously reported that blockage of mitochondrial calcium uniporter (MCU) provided benefit in the early brain injury after experimental SAH. This study was undertaken to identify whether blockage of MCU could ameliorate iron accumulation-associated brain injury following SAH. Therefore, we used two reagents ruthenium red (RR) and spermine (Sper) to inhibit MCU. Sprague-Dawley (SD) rats were randomly divided into four groups including sham, SAH, SAH+RR, and SAH+Sper. Biochemical analysis and histological assays were performed. The results confirmed the iron accumulation in temporal lobe after SAH. Interestingly, blockage of MCU dramatically reduced the iron accumulation in this area. The mechanism was revealed that inhibition of MCU reversed the down-regulation of iron regulatory protein (IRP) 1/2 and increase of ferritin. Iron-sulfur cluster dependent-aconitase activity was partially conserved when MCU was blocked. In consistence with this and previous report, ROS levels were notably reduced and ATP supply was rescued; levels of cleaved caspase-3 dropped; and integrity of neurons in temporal lobe was protected. Taken together, our results indicated that blockage of MCU could alleviate iron accumulation and the associated injury following SAH. These findings suggest that the alteration of calcium and iron homeostasis be coupled and MCU be considered to be a therapeutic target for patients suffering from SAH. PMID:25529443

  1. Iron metabolism: current facts and future directions

    PubMed Central

    Tandara, Leida; Salamunic, Ilza

    2012-01-01

    Iron metabolism has been intensively examined over the last decade and there are many new players in this field which are worth to be introduced. Since its discovery many studies confirmed role of liver hormone hepcidin as key regulator of iron metabolism and pointed out liver as the central organ of system iron homeostasis. Liver cells receive multiple signals related to iron balance and respond by transcriptional regulation of hepcidin expression. This liver hormone is negative regulator of iron metabolism that represses iron efflux from macrophages, hepatocytes and enterocytes by its binding to iron export protein ferroportin. Ferroportin degradation leads to cellular iron retention and decreased iron availability. At level of a cell IRE/IRP (iron responsive elements/iron responsive proteins) system allows tight regulation of iron assimilation that prevents an excess of free intracellular iron which could lead to oxidative stress and damage of DNA, proteins and lipid membranes by ROS (reactive oxygen species). At the same time IRE/IRP system provides sufficient iron in order to meet the metabolic needs. Recently a significant progress in understanding of iron metabolism has been made and new molecular participants have been characterized. Article gives an overview of the current understanding of iron metabolism: absorption, distribution, cellular uptake, release, and storage. We also discuss mechanisms underlying systemic and cellular iron regulation with emphasis on central regulatory hormone hepcidin. PMID:23092063

  2. Iron indices: what do they really mean?

    PubMed

    Coyne, D

    2006-05-01

    Routine monitoring of body iron stores is an essential component of overall management for the patient on hemodialysis. Adequate iron levels are important for the prevention and treatment of iron-deficiency anemia, which is associated with reduced physical functioning, cardiovascular disease, and poor quality of life. Hemodialysis patients are at especially high risk for iron-deficiency anemia, owing to continuous blood losses and supraphysiologic levels of erythropoiesis driven by recombinant human erythropoietin therapy. Unfortunately, the accurate determination of iron status in these patients can be a challenging task, which is made more difficult by inflammation, infections, and the large number of comorbid conditions that can affect commonly used indices of body iron stores. Despite their limitations, transferrin saturation (TSAT) and serum ferritin remain the cornerstones of iron status assessment. Because these values can be altered by a number of non-iron-related factors, it is necessary to go beyond these measures and draw upon additional sources of information to determine the patient's iron status. Other important factors to consider when assessing the need for iron therapy include evidence of underlying inflammatory processes that may block iron mobilization and distort the standard iron indices, the results of alternative iron indices, and the patient's recent history of iron administration. Frequently, the response to a gram of intravenous (i.v.) iron is a safe and effective way to determine the role of iron deficiency in the anemia of the problematic patient. The chronic inflammatory state associated with malnutrition and clinical or subclinical infections substantially increases the risk of misdiagnosing the patient with iron overload and may place the patient at risk of iron deficiency owing to inappropriate withdrawal of i.v. iron therapy. To avoid the risks of withholding iron therapy, the nephrologist must keep this relationship in mind whenever serum ferritin testing suggests replete iron stores, whereas TSAT testing suggests insufficient iron availability. PMID:16830699

  3. Exploratorium: Iron Science Teacher

    NSDL National Science Digital Library

    People in the Bay Area love to cook, and that can mean mixing up everything from home-grown arugula to free trade pumpkins. The good folks at San Francisco's Exploratorium have cooked up the Iron Science Teacher presentations in an attempt to bring together the worlds of science and the culinary arts. To no one's surprise, they have succeeded, and the results include a fine mix of science activities that are both fun and enlightening. Visitors can dive right in by looking over some of their recent endeavors, which have included such items as candy, apples, chocolate, fruit cake, pumpkins, and marshmallow peeps. There are other areas of the site that bring together previous webcasts that have covered kitchen items, common household items, and even things one might find in a recycling bin.

  4. Metallurgy Beyond Iron

    NASA Astrophysics Data System (ADS)

    Gallino, Isabella; Busch, Ralf

    2009-08-01

    Metallurgy is one of the oldest sciences. Its history can be traced back to 6000 BCE with the discovery of Gold, and each new discovery - Copper, Silver, Lead, Tin, Iron and Mercury - marked the beginning of a new era of civilization. Currently there are 86 known metals, but until the end of the 17th century, only 12 of these were known. Steel (Fe-C alloy) was discovered in the 11th century BCE; however, it took until 1709 CE before we mastered the smelting of pig-iron by using coke instead of charcoal and started the industrial revolution. The metallurgy of nowadays is mainly about discovering better materials with superior properties to fulfil the increasing demand of the global market. Promising are the Glassy Metals or Bulk Metallic Glasses (BMGs) - discovered at first in the late 50s at the California Institute of Technology - which are several times stronger than the best industrial steels and 10-times springier. The unusual structure that lacks crystalline grains makes BMGs so promising. They have a liquid-like structure that means they melt at lower temperatures, can be moulded nearly as easily as plastics, and can be shaped into features just 10 nm across. The best BMG formers are based on Zr, Pd, Pt, Ca, Au and, recently discovered, also Fe. They have typically three to five components with large atomic size mismatch and a composition close to a deep eutectic. Packing in such liquids is very dense, with a low content of free volume, resulting in viscosities that are several orders of magnitude higher than in pure metal melts.

  5. Body iron and individual iron prophylaxis in pregnancy—should the iron dose be adjusted according to serum ferritin?

    Microsoft Academic Search

    Nils Milman; Keld-Erik Byg; Thomas Bergholt; Lisbeth Eriksen; Anne-Mette Hvas

    2006-01-01

    This study aims to evaluate iron prophylaxis in pregnant women from the individual aspect, i.e. according to serum ferritin levels at the beginning of pregnancy, and to assess which dose of iron would be adequate to prevent iron deficiency (ID) and iron deficiency anaemia (IDA) during pregnancy and postpartum. A randomised, double-blind study comprising 301 healthy Danish pregnant women allocated

  6. Iron homeostasis in the neonate.

    PubMed

    Collard, Keith J

    2009-04-01

    The regulation of the availability of micronutrients is particularly critical during periods of rapid growth and differentiation such as the fetal and neonatal stages. Both iron deficiency and excess during the early weeks of life can have severe effects on neurodevelopment that may persist into adulthood and may not be corrected by restoration of normal iron levels. This article provides a succinct overview of our current understanding of the extent to which newborns, particularly premature newborns, are able (or not able) to regulate their iron status according to physiologic need. Postnatal development of factors important to iron homeostasis such as intestinal transport, extracellular transport, cellular uptake and storage, intracellular regulation, and systemic control are examined. Also reviewed are how factors peculiar to the sick and premature neonate can further adversely influence iron homeostasis and exacerbate iron-induced oxidative stress, predispose the infant to bacterial infections, and, thus, compromise his or her clinical situation further. The article concludes with a discussion of the areas of relative ignorance that require urgent investigation to rectify our lack of understanding of iron homeostasis in what is a critical stage of development. PMID:19336381

  7. Iron homeostasis in breast cancer.

    PubMed

    Marques, Oriana; da Silva, Berta Martins; Porto, Graça; Lopes, Carlos

    2014-05-28

    Iron is an essential element and a critical component of molecules involved in energy production, cell cycle and intermediate metabolism. However, the same characteristic chemistry that makes it so biologically versatile may lead to iron-associated toxicity as a consequence of increased oxidative stress. The fact that free iron accumulates with age and generates ROS led to the hypothesis that it could be involved in the etiogenesis of several chronic diseases. Iron has been consistently linked to carcinogenesis, either through persistent failure in the redox balance or due to its critical role in cellular proliferation. Several reports have given evidence that alterations in the import, export and storage of cellular iron may contribute to breast cancer development, behavior and recurrence. In this review, we summarize the basic mechanisms of systemic and cellular iron regulation and highlight the findings that link their deregulation with breast cancer. To conclude, progresses in iron chelation therapy in breast cancer, as a tool to fight chemotherapy resistance, are also reviewed. PMID:24486738

  8. Comparison of polysaccharide iron complexes used as iron supplements.

    PubMed

    Coe, E M; Bowen, L H; Speer, J A; Bereman, R D

    1995-03-01

    An oral hematinic marketed as "water soluble polysaccharide iron complex" (Vitaline Formulas) has been characterized using x-ray powder diffraction and Mössbauer spectroscopy. Another polysaccharide iron complex marketed as Niferex (Central Pharmaceuticals) has been previously studied by us and found to have a core similar to ferrihydrite, but with some long-range order of the mineral akaganéite, beta-FeOOH. The latter is seen in other ferric carbohydrate complexes synthesized by the hydrolysis of FeCl3. This commercial product, however, is very different and has a mixture of iron components including hematite (alpha-Fe2O3) magnetite (Fe3O4), goethite (alpha-FeOOH), iron metal, and a ferrous salt. PMID:7775981

  9. Magnetic study of iron sorbitol

    NASA Astrophysics Data System (ADS)

    Lázaro, F. J.; Larrea, A.; Abadía, A. R.; Romero, M. S.

    2002-09-01

    A magnetic study of iron sorbitol, an iron-containing drug to treat the iron deficiency anemia is presented. Transmission electron microscopy reveals that the system contains nanometric particles with an average diameter of 3 nm whose composition is close to two-line ferrihydrite. The characterisation by magnetisation and AC susceptibility measurements indicates superparamagnetic behaviour with progressive magnetic blocking starting at 8 K. The quantitative analysis of the magnetic results indicates that the system consists of an assembly of very small magnetic moments, presumably originated by spin uncompensation of the antiferromagnetic nanoparticles, with Arrhenius type magnetic dynamics.

  10. Multiphoton Dissociation of Iron Carbonyls: Emission from Atomic Iron

    Microsoft Academic Search

    Joseph J. BelBruno; Russell B. Quinney

    1996-01-01

    The third harmonic of the Nd:YAG laser is used to photodissociate Fe(CO)3L, where L = C4H6 or C6H8. The resulting emission is analyzed and observed to originate from high lying states of atomic iron. Iron ions are concurrently produced at laser energies as low as 20 ?J pulse. The nature of the emission spectrum is dependent upon the total pressure

  11. Thermal dissociation of iron carbonyls during growth of iron whiskers

    Microsoft Academic Search

    V. N. Babin; Yu. A. Belousov; I. V. Dobryakova; Yu. S. Nekrasov; V. G. Syrkin; A. A. Uel’skii

    2004-01-01

    Methods for the preparation of iron whiskers in chemical transport reactions of thermal dissociation of iron penta- and dodecacarbonyls and carbidocarbonyl clusters Fe5C(CO)15 were described. The morphology, structure, and chemical composition of the whiskers were studied. The main factors determining the growth rate and mechanical properties of the whiskers were revealed. A model for the mechanism of thermal dissociation of

  12. Multiphoton dissociation of iron carbonyls: Emission from atomic iron

    Microsoft Academic Search

    Joseph J. BeiBruno; Russell B. Quinney

    1995-01-01

    The third harmonic of the Nd:YAG laser is used to photodissociate Fe(CO)3L, where L = C4H6 or Q6H8. The resulting emission is analyzed and observed to originate from high lying states of atomic iron. Iron ions are concurrently produced at laser energies as low as 20 ?J pulse. The nature of the emission spectrum is dependent upon the total pressure

  13. Iron Oxide Based High Temperature Desulfurization Sorbent

    Microsoft Academic Search

    Ju Shangguan; Pengfei Hou; Yongjun Zhu; Litong Liang; Fang Shen; Huiling Fan; Maoqian Miao

    2009-01-01

    Iron oxide sorbent is used as high temperature desulfurization sorbent due to high sulfur capacity, easy regeneration and recovery elemental sulfur. In this paper, the iron oxide based high-temperature sorbent was obtained by mixing iron oxide with calcium oxide, extrudating and calcinating. The sulfidation, reduction and regeneration performance for the prepared iron oxide based desulfurization sorbent were conducted. The phases

  14. Iron incorporation and post-malaria anaemia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Iron supplementation is employed to treat post-malarial anaemia in environments where iron deficiency is common. Malaria induces an intense inflammatory reaction that stalls reticulo-endothelial macrophagal iron recycling from haemolysed red blood cells and inhibits oral iron absorption, but the mag...

  15. Process for the synthesis of iron powder

    Microsoft Academic Search

    Welbon

    1983-01-01

    A process for preparing iron powder suitable for use in preparing the iron-potassium perchlorate heat-powder fuel mixture used in thermal batteries, comprises preparing a homogeneous, dense iron oxide hydroxide precipitate by homogeneous precipitation from an aqueous mixture of a ferric salt, formic or sulfuric acid, ammonium hydroxide and urea as precipitating agent; and then reducing the dense iron oxide hydroxide

  16. THE IRON PROJECT Anil K. Pradhan

    E-print Network

    Pradhan, Anil

    THE IRON PROJECT Anil K. Pradhan Department of Astronomy, The Ohio State University, Columbus, Ohio and application of these methods is the aim of the Iron Project. At present the primary focus is on collisional processes for all ions of iron, Fe I -- FeXXVI, and other iron­peak elements; new work on radiative

  17. Iron oxyhydroxide mineralization on microbial extracellular polysaccharides

    E-print Network

    Iron oxyhydroxide mineralization on microbial extracellular polysaccharides Clara S. Chan a Iron biominerals can form in neutral pH microaerophilic environments where microbes both catalyze iron, and high-resolution transmission electron microscopy (HRTEM). We focused on iron microbial mat samples from

  18. Iron indices: What do they really mean?

    Microsoft Academic Search

    D Coyne

    2006-01-01

    Routine monitoring of body iron stores is an essential component of overall management for the patient on hemodialysis. Adequate iron levels are important for the prevention and treatment of iron-deficiency anemia, which is associated with reduced physical functioning, cardiovascular disease, and poor quality of life. Hemodialysis patients are at especially high risk for iron-deficiency anemia, owing to continuous blood losses

  19. Iron loss analysis in linear dc motor

    SciTech Connect

    Hippner, M.; Yamada, H.; Mizuno, T.

    1999-09-01

    The paper presents analysis of iron loss in a linear dc motor with a solid iron core. The analysis is based on a finite element magnetic field solution. The influence of magnetic bias on the iron loss is discussed. The results of the iron loss calculations are verified experimentally.

  20. Acquisition of Iron by Gardnerella vaginalis

    Microsoft Academic Search

    GREGORY P. JAROSIK; CAROL BETH LAND; PATRICE DUHON

    1998-01-01

    Six Gardnerella vaginalis strains were examined for the ability to utilize various iron-containing compounds as iron sources. In a plate bioassay, all six strains acquired iron from ferrous chloride, ferric chloride, ferrous sulfate, ferric ammonium citrate, ferrous ammonium sulfate, bovine and equine hemin, bovine catalase, and equine, bovine, rabbit, and human hemoglobin. All six strains also acquired iron from human

  1. Nanofiltration and Fenton's process over iron shavings for surfactants removal.

    PubMed

    Martins, Rui C; Nunes, Marta; Gando-Ferreira, Licínio M; Quinta-Ferreira, Rosa M

    2014-01-01

    The presence of surfactants in wastewater composition tends to jeopardize the efficiency of the traditional aerobic treatment processes. In this regard, the application of Fenton's reaction and nanofiltration as single processes and integrated (nanofiltration followed by Fenton's process) was investigated on the abatement of a solution containing two surfactants usually found in effluents coming from detergent industry (dodecylbenzene--DDB and sodium lauryl ether sulphate--SLES). The potential of a solid waste (iron shavings) as catalyst in the Fenton's process was evaluated and the reaction system was optimized regarding the key operating parameters (iron and hydrogen peroxide concentration and pH). The highest chemical oxygen demand (COD) degradation (66%) was attained for pH 3, [H2O2] = 32 mM and 50 g/L of iron shavings. Besides, it was concluded that oxidation was due to hydroxyl radicals adsorbed on the metal surface even if bulk interaction between hydrogen peroxide and dissolved iron cannot be neglected. The main variables ruling nanofiltration were evaluated (pH, temperature and cross-flow rate). Eighty-four percent of COD rejection was determined at pH 7.5, cross-flow 14.4 cm3 s(-1), 20 degrees C and 15 bar of pressure drop. Finally, nanofiltration followed by Fenton's process under the best conditions was integrated; however, no significant improvement was attained with 85% of COD being globally removed. PMID:25145192

  2. A methodology to estimate remaining service life of grey cast iron water mains

    Microsoft Academic Search

    Balvant Rajani; Jon Makar

    2000-01-01

    The decision to repair, renew, or replace existing old grey cast iron mains is typically based on performance indicators such as structural integrity, hydraulic efficiency, system reliability, and water quality. Structural integrity (of - ten quantified as the number of main breaks per kilometre or mile per year) is the most common performance indica- tor. However, these indicators represent past

  3. Impact of Landfill Leachate on Iron Release From Northwest Florida Iron Rich Soils

    Microsoft Academic Search

    Pawan Kumar Subramaniam; Mitch Williams

    2007-01-01

    Landfill leachate is blamed for elevated levels of iron in the groundwater monitoring wells downgradient of unlined landfills. It is suspected that the geochemical and geomicrobial iron reduction\\/oxidation processes are responsible for the iron release to the groundwater. When conditions permit, microbial mediated iron reduction and release may be the mechanism for elevated iron observations in the groundwater. In regions

  4. 49 CFR 192.373 - Service lines: Cast iron and ductile iron.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Service lines: Cast iron and ductile iron. 192.373 Section 192.373 Transportation...and Service Lines § 192.373 Service lines: Cast iron and ductile iron. (a) Cast or ductile iron...

  5. 49 CFR 192.373 - Service lines: Cast iron and ductile iron.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Service lines: Cast iron and ductile iron. 192.373 Section 192.373 Transportation...and Service Lines § 192.373 Service lines: Cast iron and ductile iron. (a) Cast or ductile iron...

  6. 49 CFR 192.373 - Service lines: Cast iron and ductile iron.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Service lines: Cast iron and ductile iron. 192.373 Section 192.373 Transportation...and Service Lines § 192.373 Service lines: Cast iron and ductile iron. (a) Cast or ductile iron...

  7. 49 CFR 192.373 - Service lines: Cast iron and ductile iron.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Service lines: Cast iron and ductile iron. 192.373 Section 192.373 Transportation...and Service Lines § 192.373 Service lines: Cast iron and ductile iron. (a) Cast or ductile iron...

  8. 49 CFR 192.373 - Service lines: Cast iron and ductile iron.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Service lines: Cast iron and ductile iron. 192.373 Section 192.373 Transportation...and Service Lines § 192.373 Service lines: Cast iron and ductile iron. (a) Cast or ductile iron...

  9. Method for reducing iron losses in an iron smelting process

    DOEpatents

    Sarma, B.; Downing, K.B.

    1999-03-23

    A process of smelting iron that comprises the steps of: (a) introducing a source of iron oxide, oxygen, nitrogen, and a source of carbonaceous fuel to a smelting reactor, at least some of said oxygen being continuously introduced through an overhead lance; (b) maintaining conditions in said reactor to cause (1) at least some of the iron oxide to be chemically reduced, (2) a bath of molten iron to be created and stirred in the bottom of the reactor, surmounted by a layer of slag, and (3) carbon monoxide gas to rise through the slag; (c) causing at least some of said carbon monoxide to react in the reactor with the incoming oxygen, thereby generating heat for reactions taking place in the reactor; and (d) releasing from the reactor an offgas effluent, is run in a way that keeps iron losses in the offgas relatively low. After start-up of the process is complete, steps (a) and (b) are controlled so as to: (1) keep the temperature of the molten iron at or below about 1550 C and (2) keep the slag weight at or above about 0.8 ton per square meter. 13 figs.

  10. Method for reducing iron losses in an iron smelting process

    DOEpatents

    Sarma, Balu (Airmont, NY); Downing, Kenneth B. (Greenville, SC)

    1999-01-01

    A process of smelting iron that comprises the steps of: a) introducing a source of iron oxide, oxygen, nitrogen, and a source of carbonaceous fuel to a smelting reactor, at least some of said oxygen being continuously introduced through an overhead lance; b) maintaining conditions in said reactor to cause (i) at least some of the iron oxide to be chemically reduced, (ii) a bath of molten iron to be created and stirred in the bottom of the reactor, surmounted by a layer of slag, and (iii) carbon monoxide gas to rise through the slag; c) causing at least some of said carbon monoxide to react in the reactor with the incoming oxygen, thereby generating heat for reactions taking place in the reactor; and d) releasing from the reactor an offgas effluent, is run in a way that keeps iron losses in the offgas relatively low. After start-up of the process is complete, steps (a) and (b) are controlled so as to: e) keep the temperature of the molten iron at or below about 1550.degree. C. and f) keep the slag weight at or above about 0.8 tonne per square meter.

  11. Extracellular Iron Biomineralization by Photoautotrophic Iron-Oxidizing Bacteria ? †

    PubMed Central

    Miot, Jennyfer; Benzerara, Karim; Obst, Martin; Kappler, Andreas; Hegler, Florian; Schädler, Sebastian; Bouchez, Camille; Guyot, François; Morin, Guillaume

    2009-01-01

    Iron oxidation at neutral pH by the phototrophic anaerobic iron-oxidizing bacterium Rhodobacter sp. strain SW2 leads to the formation of iron-rich minerals. These minerals consist mainly of nano-goethite (?-FeOOH), which precipitates exclusively outside cells, mostly on polymer fibers emerging from the cells. Scanning transmission X-ray microscopy analyses performed at the C K-edge suggest that these fibers are composed of a mixture of lipids and polysaccharides or of lipopolysaccharides. The iron and the organic carbon contents of these fibers are linearly correlated at the 25-nm scale, which in addition to their texture suggests that these fibers act as a template for mineral precipitation, followed by limited crystal growth. Moreover, we evidence a gradient of the iron oxidation state along the mineralized fibers at the submicrometer scale. Fe minerals on these fibers contain a higher proportion of Fe(III) at cell contact, and the proportion of Fe(II) increases at a distance from the cells. All together, these results demonstrate the primordial role of organic polymers in iron biomineralization and provide first evidence for the existence of a redox gradient around these nonencrusting, Fe-oxidizing bacteria. PMID:19592528

  12. Extracellular iron biomineralization by photoautotrophic iron-oxidizing bacteria.

    PubMed

    Miot, Jennyfer; Benzerara, Karim; Obst, Martin; Kappler, Andreas; Hegler, Florian; Schädler, Sebastian; Bouchez, Camille; Guyot, François; Morin, Guillaume

    2009-09-01

    Iron oxidation at neutral pH by the phototrophic anaerobic iron-oxidizing bacterium Rhodobacter sp. strain SW2 leads to the formation of iron-rich minerals. These minerals consist mainly of nano-goethite (alpha-FeOOH), which precipitates exclusively outside cells, mostly on polymer fibers emerging from the cells. Scanning transmission X-ray microscopy analyses performed at the C K-edge suggest that these fibers are composed of a mixture of lipids and polysaccharides or of lipopolysaccharides. The iron and the organic carbon contents of these fibers are linearly correlated at the 25-nm scale, which in addition to their texture suggests that these fibers act as a template for mineral precipitation, followed by limited crystal growth. Moreover, we evidence a gradient of the iron oxidation state along the mineralized fibers at the submicrometer scale. Fe minerals on these fibers contain a higher proportion of Fe(III) at cell contact, and the proportion of Fe(II) increases at a distance from the cells. All together, these results demonstrate the primordial role of organic polymers in iron biomineralization and provide first evidence for the existence of a redox gradient around these nonencrusting, Fe-oxidizing bacteria. PMID:19592528

  13. Acquisition of iron by Gardnerella vaginalis.

    PubMed

    Jarosik, G P; Land, C B; Duhon, P; Chandler, R; Mercer, T

    1998-10-01

    Six Gardnerella vaginalis strains were examined for the ability to utilize various iron-containing compounds as iron sources. In a plate bioassay, all six strains acquired iron from ferrous chloride, ferric chloride, ferrous sulfate, ferric ammonium citrate, ferrous ammonium sulfate, bovine and equine hemin, bovine catalase, and equine, bovine, rabbit, and human hemoglobin. All six strains also acquired iron from human lactoferrin, but not from human transferrin, as determined by a liquid broth growth assay. Siderophore production was detected in eight G. vaginalis strains by the chrome azurol S universal chemical assay. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the cytoplasmic membrane proteins isolated from G. vaginalis 594 grown under iron-replete and iron-restricted conditions revealed several iron-regulated proteins ranging in molecular mass from 33 to 94 kDa. These results indicate that G. vaginalis may acquire iron from iron salts and host iron compounds. PMID:9746616

  14. Bionursing: signs of iron deficiency.

    PubMed

    Torrance, C; Jordan, S

    In the ninth article in our series on bionursing, the authors explain how an understanding of physiology can help nurses to identify the common signs and symptoms of iron deficiency and ensure patients receive prompt and appropriate treatment. PMID:8562358

  15. Discovery of the Iron Isotopes

    E-print Network

    A. Schuh; A. Fritsch; M. Heim; A. Shore; M. Thoennessen

    2009-09-01

    Twenty-eight iron isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  16. Iron catalyzed coal liquefaction process

    DOEpatents

    Garg, Diwakar (Macungie, PA); Givens, Edwin N. (Bethlehem, PA)

    1983-01-01

    A process is described for the solvent refining of coal into a gas product, a liquid product and a normally solid dissolved product. Particulate coal and a unique co-catalyst system are suspended in a coal solvent and processed in a coal liquefaction reactor, preferably an ebullated bed reactor. The co-catalyst system comprises a combination of a stoichiometric excess of iron oxide and pyrite which reduce predominantly to active iron sulfide catalysts in the reaction zone. This catalyst system results in increased catalytic activity with attendant improved coal conversion and enhanced oil product distribution as well as reduced sulfide effluent. Iron oxide is used in a stoichiometric excess of that required to react with sulfur indigenous to the feed coal and that produced during reduction of the pyrite catalyst to iron sulfide.

  17. Iron and Steel Phosphate Rock

    E-print Network

    Torgersen, Christian

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

  18. Neurodegeneration with Brain Iron Accumulation

    MedlinePLUS

    NINDS Neurodegeneration with Brain Iron Accumulation Information Page Synonym(s): Hallervorden-Spatz Disease, Pantothenate Kinase-Associated Neurodegeneration Table of Contents (click to jump to sections) What ...

  19. Process for the synthesis of iron powder

    DOEpatents

    Welbon, W.W.

    1983-11-08

    A process for preparing iron powder suitable for use in preparing the iron-potassium perchlorate heat-powder fuel mixture used in thermal batteries, comprises preparing a homogeneous, dense iron oxide hydroxide precipitate by homogeneous precipitation from an aqueous mixture of a ferric salt, formic or sulfuric acid, ammonium hydroxide and urea as precipitating agent; and then reducing the dense iron oxide hydroxide by treatment with hydrogen to prepare the iron powder. 2 figs.

  20. Process for the synthesis of iron powder

    DOEpatents

    Not Available

    1982-03-06

    A process for preparing iron powder suitable for use in preparing the iron-potassium perchlorate heat-powder fuel mixture used in thermal batteries, comprises preparing a homogeneous, dense iron oxide hydroxide precipitate by homogeneous precipitation from an aqueous mixture of a ferric salt, formic or sulfuric acid, ammonium hydroxide and urea as precipitating agent; and then reducing the dense iron oxide hydroxide by treatment with hydrogen to prepare the iron powder.

  1. Iron acquisition by Ornithobacterium rhinotracheale.

    PubMed

    Tabatabai, Louisa B; Zehr, Emilie S; Zimmerli, Mandy K; Nagaraja, Kakambi V

    2008-09-01

    Ornithobacterium rhinotracheale (ORT) is an emerging respiratory pathogen of poultry in North America that is causing millions of dollars in economic losses to the poultry industry. Ornithobacterium rhinotracheale is associated with airsacculitis, pleuritis, pneumonia, and consolidation of lungs. Little is known about the molecular mechanisms of infection. In this study, the mechanism of iron acquisition by O. rhinotracheale was explored. O. rhinotracheale strains grown under iron deprivation in media containing 200 microM 2,2'-dipyridyl did not secrete siderophores as measured by the chrome azurol S (CAS) agar and CAS solution assays. Filter disks impregnated with various protein-bound iron compounds and inorganic iron salts of Fe(III) and Fe(II) placed on iron-restricted agar inoculated with a lawn of O. rhinotracheale supported growth from sheep and porcine hemoglobins, ovotransferrin, Fe(III), and Fe(II), but they did not support growth from bovine transferrin, bovine apo-transferrin, bovine lactoferrin, and hemin. However, both bovine hemoglobin and transferrin supported growth of O. rhinotracheale serotype C. Four immunoreactive proteins involved in iron acquisition were identified in an O. rhinotracheale membrane extract by using mass spectrometry. Furthermore, O. rhinotracheale field strains showed differential sensitivity to 2,2'-dipyridyl. Of the 72 field strains tested, 22 strains were resistant to the iron chelator at concentrations of 50 microM and 100 microM, suggesting this attribute may be related to disease-producing potential of these strains. This is the first report on the identification of the iron acquisition mechanism of O. rhinotracheale. PMID:18939629

  2. Luminescent iron clusters in solution

    NASA Astrophysics Data System (ADS)

    Goswami, Nirmal; Baksi, Ananya; Giri, Anupam; Xavier, Paulrajpillai Lourdu; Basu, Gautam; Pradeep, Thalappil; Pal, Samir Kumar

    2014-01-01

    Metal clusters, composed of a few atoms at the core, exhibit unique properties and have potential applications. Although atomically precise clusters of noble metals have been synthesized, analogous systems of reactive metals, such as iron, have not been realized in solution due to high reactivity. Here we report the synthesis and characterization of novel iron clusters in the hemoglobin matrix that are highly luminescent (quantum yield 10% at 565 nm). The super-paramagnetic iron clusters, after successful ligand exchange from protein and phase transfer from water to chloroform using tri-octylphosphineoxide (TOPO), were detected as [Fe10(TOPO)3(H2O)3]+, [Fe13(TOPO)2(H2O)]+ and [Fe8(TOPO)(H2O)2]+ by mass spectrometry. This study lays the groundwork for exploiting unique properties of soluble iron clusters.Metal clusters, composed of a few atoms at the core, exhibit unique properties and have potential applications. Although atomically precise clusters of noble metals have been synthesized, analogous systems of reactive metals, such as iron, have not been realized in solution due to high reactivity. Here we report the synthesis and characterization of novel iron clusters in the hemoglobin matrix that are highly luminescent (quantum yield 10% at 565 nm). The super-paramagnetic iron clusters, after successful ligand exchange from protein and phase transfer from water to chloroform using tri-octylphosphineoxide (TOPO), were detected as [Fe10(TOPO)3(H2O)3]+, [Fe13(TOPO)2(H2O)]+ and [Fe8(TOPO)(H2O)2]+ by mass spectrometry. This study lays the groundwork for exploiting unique properties of soluble iron clusters. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr05784d

  3. Interactions in iron gall inks

    Microsoft Academic Search

    V. Jan?ovi?ová; M. ?eppan; B. Havlínová; M. Reháková; Z. Jakubíková

    2007-01-01

    Simple iron gall inks composed of gallic acid, ferrous sulfate, and gum arabic and in some cases also of copper(II) sulfate\\u000a were prepared. The process of iron ion complex formation with gallic acid was investigated using UV-VIS spectroscopy, pH measurements,\\u000a and by monitoring the concentration changes of Fe(II) ions. The admixture of Fe(II) ions to gallic acid induced a bathochromic

  4. Enzymes and other iron proteins

    NASA Astrophysics Data System (ADS)

    Debrunner, Peter G.

    1990-07-01

    The phenomenology of a new group of binuclear iron proteins is discussed. The common feature of these proteins is a pair of exchange coupled high spin irons in the diferric, diferrous or ferric-ferrous, trapped valence state. Of particular interest are the cases of intermediate coupling, where the zero-field splittings are comparable to the exchange and possibly the Zeeman interaction. Examples of the Mössbauer analysis of such systems in terms of a spin Hamiltonian are discussed.

  5. Development of an integrated in-situ remediation technology. Topical report for Task {number_sign}3.2 entitled, ``Modeling and iron dechlorination studies`` (September 26, 1994--August 31, 1997)

    SciTech Connect

    Shapiro, A.P.; Sivavec, T.M.; Principe, J.M. [General Electric Research and Development, Schenectady, NY (United States)

    1997-11-01

    Contamination in low-permeability soils poses a significant technical challenge to in-situ remediation efforts. Poor accessibility to the contaminants and difficulty in delivery of treatment reagents have rendered existing in-situ treatments such as bioremediation, vapor extraction, and pump and treat rather ineffective when applied to low-permeability soils present at many contaminated sites. The technology is an integrated in-situ treatment in which established geotechnical methods are used to install degradation zones directly in the contaminated soil, and electro-osmosis is utilized to move the contaminants back and forth through those zones until the treatment is complete. The present Topical Report for Task {number_sign}3.2 summarizes the modeling and dechlorination research conducted by General Electric Research and Development.

  6. Iron, Oxidative Stress and Gestational Diabetes

    PubMed Central

    Zhuang, Taifeng; Han, Huijun; Yang, Zhenyu

    2014-01-01

    Both iron deficiency and hyperglycemia are highly prevalent globally for pregnant women. Iron supplementation is recommended during pregnancy to control iron deficiency. The purposes of the review are to assess the oxidative effects of iron supplementation and the potential relationship between iron nutrition and gestational diabetes. High doses of iron (~relative to 60 mg or more daily for adult humans) can induce lipid peroxidation in vitro and in animal studies. Pharmaceutical doses of iron supplements (e.g., 10× RDA or more for oral supplements or direct iron supplementation via injection or addition to the cell culture medium) for a short or long duration will induce DNA damage. Higher heme-iron intake or iron status measured by various biomarkers, especially serum ferritin, might contribute to greater risk of gestational diabetes, which may be mediated by iron oxidative stress though lipid oxidation and/or DNA damage. However, information is lacking about the effect of low dose iron supplementation (?60 mg daily) on lipid peroxidation, DNA damage and gestational diabetes. Randomized trials of low-dose iron supplementation (?60 mg daily) for pregnant women are warranted to test the relationship between iron oxidative stress and insulin resistance/gestational diabetes, especially for iron-replete women. PMID:25255832

  7. Interactions between hepatic iron and lipid metabolism with possible relevance to steatohepatitis

    PubMed Central

    Ahmed, Umbreen; Latham, Patricia S; Oates, Phillip S

    2012-01-01

    The liver is an important site for iron and lipid metabolism and the main site for the interactions between these two metabolic pathways. Although conflicting results have been obtained, most studies support the hypothesis that iron plays a role in hepatic lipogenesis. Iron is an integral part of some enzymes and transporters involved in lipid metabolism and, as such, may exert a direct effect on hepatic lipid load, intrahepatic metabolic pathways and hepatic lipid secretion. On the other hand, iron in its ferrous form may indirectly affect lipid metabolism through its ability to induce oxidative stress and inflammation, a hypothesis which is currently the focus of much research in the field of non-alcoholic fatty liver disease/non-alcoholic steatohepatitis (NAFLD/NASH). The present review will first discuss how iron might directly interact with the metabolism of hepatic lipids and then consider a new perspective on the way in which iron may have a role in the two hit hypothesis for the progression of NAFLD via ferroportin and the iron regulatory molecule hepcidin. The review concludes that iron has important interactions with lipid metabolism in the liver that can impact on the development of NAFLD/NASH. More defined studies are required to improve our understanding of these effects. PMID:23002334

  8. Thermal Infrared Emission Measurements of Iron Sulfate and Phosphate Samples for Application to Mars

    NASA Astrophysics Data System (ADS)

    Lane, M. D.; Bishop, J. L.; Dyar, M. D.

    2012-12-01

    Iron sulfate and phosphate minerals have been identified on Mars through the integration of data from multiple instruments on the Mars Exploration Rovers (MERs). In order to more thoroughly study the MER Mini-Thermal Emission Spectrometer (Mini-TES) and Mars Global Surveyor TES data sets, suites of iron sulfate minerals and phosphate minerals have been collected; the chemistry of each sample has been verified by X-ray diffraction analysis and thermal emission spectra have been obtained. Obtaining pure, well-characterized samples has been arduous, but the spectra to be presented were acquired of chemically verified samples. Iron sulfate and phosphate minerals consist of XO4 tetrahedra (where X is S and P, respectively) polymerized with MO6 polyhedra (where M is a metal cation) in various configurations. These mid-infrared iron sulfate and phosphate spectra are dominated by features associated with the X-O vibrations of the SO4 and PO4 tetrahedra, similar to non-iron-bearing sulfates. Many of the iron sulfate chemistries studied include bound water (OH and/or H2O), hence their iron sulfate spectra exhibit a water bending feature that lies between approximately 1700 and 1630 cm^-1. Typically, the phosphate spectra are less hydrous. Within their mineral classes, iron sulfate and phosphate spectra exhibit similarities, which generally align by Strunz groups. These well-characterized spectra will enable further analysis of spectral data sets from Mars.

  9. Glucose metabolism in the Belgrade rat, a model of iron-loading anemia.

    PubMed

    Jia, Xuming; Kim, Jonghan; Veuthey, Tania; Lee, Chih-Hao; Wessling-Resnick, Marianne

    2013-06-15

    The iron-diabetes hypothesis proposes an association between iron overload and glucose metabolism that is supported by a number of epidemiological studies. The prevalence of type 2 diabetes in patients with hereditary hemochromatosis and iron-loading thalassemia supports this hypothesis. The Belgrade rat carries a mutation in the iron transporter divalent metal transporter 1 (DMT1) resulting in iron-loading anemia. In this study, we characterized the glycometabolic status of the Belgrade rat. Belgrade rats displayed normal glycemic control. Insulin signaling and secretion were not impaired, and pancreatic tissue did not incur damage despite high levels of nonheme iron. These findings suggest that loss of DMT1 protects against oxidative damage to the pancreas and helps to maintain insulin sensitivity despite iron overload. Belgrade rats had lower body weight but increased food consumption compared with heterozygous littermates. The unexpected energy balance was associated with increased urinary glucose output. Increased urinary excretion of electrolytes, including iron, was also observed. Histopathological evidence suggests that altered renal function is secondary to changes in kidney morphology, including glomerulosclerosis. Thus, loss of DMT1 appears to protect the pancreas from injury but damages the integrity of kidney structure and function. PMID:23599042

  10. Simultaneous Measurements of Temperature and Iron-Slag Ratio at Taphole of Blast Furnace

    NASA Astrophysics Data System (ADS)

    Sugiura, M.; Shinotake, A.; Nakashima, M.; Omoto, N.

    2014-07-01

    As the initial process in an integrated steel-making plant, molten iron is produced in a blast furnace. The molten iron has a temperature between 1700 K and 1900 K. The outflow stream discharged from a taphole comprises the molten iron and slag (which is a mixture of molten oxides). Monitoring of the stream temperature is important because it has information on the thermal condition inside the blast furnace. A newly developed simultaneous measurement technique for temperature and iron-slag ratio is reported. A monochromatic CCD camera with a short exposure time is used to obtain a thermal image of the rapidly moving stream. The thermal image has a marble-like pattern caused by the physical separation of the iron and slag and their different optical properties. Iron thermometry is realized by automatically detecting the peak of the iron gray-level distribution on a histogram. Meanwhile, the thermal radiance of the semitransparent slag varies as a function of the thickness. The slag temperature is calculated from the maximum gray level, presuming that the emissivity of the slag is constant at a thick slag part. The slag ratio is measured by counting the number of pixels on the histogram. A field test was carried out at an operating blast furnace. The iron temperature, slag temperature, and slag ratio were successfully measured. This multiple image measurement is expected to be the new information source for stable blast furnace operation.

  11. Chelation of mitochondrial iron prevents seizure-induced mitochondrial dysfunction and neuronal injury.

    PubMed

    Liang, Li-Ping; Jarrett, Stuart G; Patel, Manisha

    2008-11-01

    Chelatable iron is an important catalyst for the initiation and propagation of free radical reactions and implicated in the pathogenesis of diverse neuronal disorders. Studies in our laboratory have shown that mitochondria are the principal source of reactive oxygen species production after status epilepticus (SE). We asked whether SE modulates mitochondrial iron levels by two independent methods and whether consequent mitochondrial dysfunction and neuronal injury could be ameliorated with a cell-permeable iron chelator. Kainate-induced SE resulted in a time-dependent increase in chelatable iron in mitochondrial but not cytosolic fractions of the rat hippocampus. Systemically administered N,N'-bis (2-hydroxybenzyl) ethylenediamine-N,N'-diacetic acid (HBED), a synthetic iron chelator, ameliorated SE-induced changes in chelatable iron, mitochondrial oxidative stress (8-hydroxy-2' deoxyguanosine and glutathione depletion), mitochondrial DNA integrity and hippocampal cell loss. Measurement of brain HBED levels after systemic administration confirmed its penetration in hippocampal mitochondria. These results suggest a role for mitochondrial iron in the pathogenesis of SE-induced brain damage and subcellular iron chelation as a novel therapeutic approach for its management. PMID:18987191

  12. Glucose metabolism in the Belgrade rat, a model of iron-loading anemia

    PubMed Central

    Jia, Xuming; Kim, Jonghan; Veuthey, Tania; Lee, Chih-Hao

    2013-01-01

    The iron-diabetes hypothesis proposes an association between iron overload and glucose metabolism that is supported by a number of epidemiological studies. The prevalence of type 2 diabetes in patients with hereditary hemochromatosis and iron-loading thalassemia supports this hypothesis. The Belgrade rat carries a mutation in the iron transporter divalent metal transporter 1 (DMT1) resulting in iron-loading anemia. In this study, we characterized the glycometabolic status of the Belgrade rat. Belgrade rats displayed normal glycemic control. Insulin signaling and secretion were not impaired, and pancreatic tissue did not incur damage despite high levels of nonheme iron. These findings suggest that loss of DMT1 protects against oxidative damage to the pancreas and helps to maintain insulin sensitivity despite iron overload. Belgrade rats had lower body weight but increased food consumption compared with heterozygous littermates. The unexpected energy balance was associated with increased urinary glucose output. Increased urinary excretion of electrolytes, including iron, was also observed. Histopathological evidence suggests that altered renal function is secondary to changes in kidney morphology, including glomerulosclerosis. Thus, loss of DMT1 appears to protect the pancreas from injury but damages the integrity of kidney structure and function. PMID:23599042

  13. The molecular basis of iron overload disorders and iron-linked anemias

    Microsoft Academic Search

    Jerry KaplanDiane; Diane M. Ward; Ivana De Domenico

    2011-01-01

    Iron homeostasis in vertebrates requires coordination between cells that export iron into plasma and those that utilize or\\u000a store plasma iron. The coordination of iron acquisition and utilization is mediated by the interaction of the peptide hormone\\u000a hepcidin and the iron exporter ferroportin. Hepcidin levels are increased during iron sufficiency and inflammation and are\\u000a decreased in hypoxia or erythropoiesis. Hepcidin

  14. Brain Iron, Transferrin and Ferritin Concentrations Are Altered in Developing Iron-Deficient Rats1

    Microsoft Academic Search

    QING CHEN; JAMES R. CONNOR; ANDJOHN L BEARD

    To study the iron, transferrin, and ferritin distribution at subcellular levels in response to acute dietary iron deficiency, we tested the hypothesis that early post-weaning iron deficiency can change iron and iron regulatory protein concentrations in rat brain. Male Sprague-Dawley rats were fed diets containing either 2 or 35 ng iron\\/g for 2, 3 or 4 wk starting at 21

  15. Synthesis and characterization of iron, iron oxide and iron carbide nanostructures

    NASA Astrophysics Data System (ADS)

    Snovski, Ron; Grinblat, Judith; Sougrati, Moulay-Tahar; Jumas, Jean-Claude; Margel, Shlomo

    2014-01-01

    Magnetic iron oxide (Fe3O4 and ?-Fe2O3) and iron carbide (Fe3C) nanoparticles of different geometrical shapes: cubes, spheres, rods and plates, have been prepared by thermal decomposition of a mixture containing the metal precursor Fe(CO)5 and the stabilizer polyvinylpyrrolidone (PVP) at 300 °C in a sealed cell under inert atmosphere. The thermal decomposition process was performed for 4 or 24 h at ([PVP]/[Fe(CO)5]) (w/v) ratio of 1:1 or 1:5. Elemental iron nanospheres embedded within a mixture of amorphous and graphitic carbon coating were obtained by hydrogen reduction of the prepared iron oxide and iron carbide nanoparticles at 450 °C. The formation of the graphitic carbon phase at such a low temperature is unique and probably obtained by catalysis of the elemental iron nanoparticles. Changing the annealing time period and the ([PVP]/[Fe(CO)5]) ratio allowed control of the composition, size, size distribution, crystallinity, geometrical shape and magnetic properties of the different magnetic nanoparticles.

  16. Investigation of the amount of dissolved iron in food cooked in Chinese iron pots and estimation of daily iron intake.

    PubMed

    Liu, D Y; Chen, Z G; Lei, H Q; Lu, M Q; Li, R; Li, L X

    1990-09-01

    The amount of dissolved iron in food cooked in Chinese iron pots and that in food cooked in aluminum, stainless steel, and clay pots were determined. It was found that the amount of dissolved iron in food cooked in Chinese iron pots was two to five times higher than that in food cooked in the other types of pots. According to the test results, the estimated increase in daily iron intake was about 14.5 mg for adults and 7.4 mg for children when Chinese iron pots were used. PMID:2252546

  17. Iron for proliferation of cell lines and hematopoietic progenitors: Nailing down the intracellular functional iron concentration.

    PubMed

    Pourcelot, Emmanuel; Lénon, Marine; Mobilia, Nicolas; Cahn, Jean-Yves; Arnaud, Josiane; Fanchon, Eric; Moulis, Jean-Marc; Mossuz, Pascal

    2015-07-01

    Iron is an essential nutrient which must be provided in sufficient amounts to support growth of eukaryotic cells. All organisms devote specialized pathways to ensure proper delivery. Yet, a quantitative assessment of the intra-cellular iron concentration needed to allow the cell cycle to proceed in mammalian cells is missing. Starting from iron-depleted cell lines or primary hematopoietic progenitors prepared with clinically implemented iron chelators, replenishment via transferrin and other iron sources has been quantitatively monitored through the main endogenous markers of the cellular iron status, namely proteins involved in the uptake (transferrin receptor), the storage (ferritin), and the sensing (Iron Regulatory Proteins) of iron. When correlated with measurements of iron concentrations and indicators of growth, this minimally intrusive approach provided an unprecedented estimate of the intracellular iron concentration acting upon iron-centered regulatory pathways. The data were analyzed with the help of a previously developed theoretical treatment of cellular iron regulation. The minimal cellular iron concentration required for cell division was named functional iron concentration (FIC) to distinguish it from previous estimates of the cellular labile iron. The FIC falls in the low nanomolar range for all studied cells, including hematopoietic progenitors. These data shed new light on basic aspects of cellular iron homeostasis by demonstrating that sensing and regulation of iron occur well below the concentrations requiring storage or becoming noxious in pathological conditions. The quantitative assessment provided here is relevant for monitoring treatments of conditions in which iron provision must be controlled to avoid unwanted cellular proliferation. PMID:25827953

  18. Sequestration and Scavenging of Iron in Infection

    PubMed Central

    Parrow, Nermi L.; Fleming, Robert E.

    2013-01-01

    The proliferative capability of many invasive pathogens is limited by the bioavailability of iron. Pathogens have thus developed strategies to obtain iron from their host organisms. In turn, host defense strategies have evolved to sequester iron from invasive pathogens. This review explores the mechanisms employed by bacterial pathogens to gain access to host iron sources, the role of iron in bacterial virulence, and iron-related genes required for the establishment or maintenance of infection. Host defenses to limit iron availability for bacterial growth during the acute-phase response and the consequences of iron overload conditions on susceptibility to bacterial infection are also examined. The evidence summarized herein demonstrates the importance of iron bioavailability in influencing the risk of infection and the ability of the host to clear the pathogen. PMID:23836822

  19. Mössbauer investigation of iron uptake in wheat

    NASA Astrophysics Data System (ADS)

    Kovács, K.; Kuzmann, E.; Fodor, F.; Cseh, E.; Homonnay, Z.; Vértes, A.

    2008-07-01

    Iron uptake and distribution in wheat roots were studied with 57Fe Mössbauer spectroscopy. Plants were grown both in iron sufficient and in iron deficient nutrient solutions. Mössbauer spectra of the frozen iron sufficient roots exhibited three iron(III) components with the typical average Mössbauer parameters of ? = 0.50 mm s - 1, ? = 0.43 mm s - 1, ? = 0.50 mm s - 1, ? = 0.75 mm s - 1 and ? = 0.50 mm s - 1, ? = 1.20 mm s - 1 at 80 K. These doublets are very similar to those obtained earlier for cucumber [0], which allows us to suppose that iron is stored in a very similar way in different plants. No ferrous iron could be identified in any case, not even in the iron deficient roots, which confirms the mechanism proposed for iron uptake in the graminaceous plants.

  20. Hepcidin: regulation of the master iron regulator

    PubMed Central

    Rishi, Gautam; Wallace, Daniel F.; Subramaniam, V. Nathan

    2015-01-01

    Iron, an essential nutrient, is required for many diverse biological processes. The absence of a defined pathway to excrete excess iron makes it essential for the body to regulate the amount of iron absorbed; a deficiency could lead to iron deficiency and an excess to iron overload and associated disorders such as anaemia and haemochromatosis respectively. This regulation is mediated by the iron-regulatory hormone hepcidin. Hepcidin binds to the only known iron export protein, ferroportin (FPN), inducing its internalization and degradation, thus limiting the amount of iron released into the blood. The major factors that are implicated in hepcidin regulation include iron stores, hypoxia, inflammation and erythropoiesis. The present review summarizes our present knowledge about the molecular mechanisms and signalling pathways contributing to hepcidin regulation by these factors. PMID:25826005

  1. Retinal iron homeostasis in health and disease

    PubMed Central

    Song, Delu; Dunaief, Joshua L.

    2013-01-01

    Iron is essential for life, but excess iron can be toxic. As a potent free radical creator, iron generates hydroxyl radicals leading to significant oxidative stress. Since iron is not excreted from the body, it accumulates with age in tissues, including the retina, predisposing to age-related oxidative insult. Both hereditary and acquired retinal diseases are associated with increased iron levels. For example, retinal degenerations have been found in hereditary iron overload disorders, like aceruloplasminemia, Friedreich's ataxia, and pantothenate kinase-associated neurodegeneration. Similarly, mice with targeted mutation of the iron exporter ceruloplasmin and its homolog hephaestin showed age-related retinal iron accumulation and retinal degeneration with features resembling human age-related macular degeneration (AMD). Post mortem AMD eyes have increased levels of iron in retina compared to age-matched healthy donors. Iron accumulation in AMD is likely to result, in part, from inflammation, hypoxia, and oxidative stress, all of which can cause iron dysregulation. Fortunately, it has been demonstrated by in vitro and in vivo studies that iron in the retinal pigment epithelium (RPE) and retina is chelatable. Iron chelation protects photoreceptors and retinal pigment epithelial cells (RPE) in a variety of mouse models. This has therapeutic potential for diminishing iron-induced oxidative damage to prevent or treat AMD. PMID:23825457

  2. Altered systemic iron metabolism in Parkinson's disease.

    PubMed

    Logroscino, G; Marder, K; Graziano, J; Freyer, G; Slavkovich, V; LoIacono, N; Cote, L; Mayeux, R

    1997-09-01

    Iron deposition in the substantia nigra in Parkinson's disease has been associated with an increase in lactoferrin receptors and a reduction in ferritin concentration. This accumulation of iron in the brain may accelerate free radical formation, lipid peroxidation, and neuronal death. Remarkably, there are few data available concerning systemic iron metabolism in Parkinson's disease. We measured total iron binding capacity and circulating iron, ferritin, transferrin, and transferrin receptors; calculated transferrin saturation; and estimated dietary iron intake in patients with idiopathic Parkinson's disease and in controls. Concentrations of circulating iron, ferritin, and transferrin as well as total iron binding capacity and transferrin saturation were significantly lower in patients than controls. There were no differences in transferrin receptors or dietary intake of iron. The decrease in levels of systemic ferritin and transferrin and the total iron binding capacity parallels observations in a Parkinson's disease brain, but the reductions in serum iron concentrations and transferrin saturation do not, and were unexpected. These results suggest the existence of a defect in the systems that regulate the synthesis of the major proteins of iron metabolism in the liver as well as the brain in Parkinson's disease that may, over time, expedite entry of iron into the brain and decrease iron in the extracellular compartment. PMID:9305329

  3. Expression of Heteropolymeric Ferritin Improves Iron Storage in Saccharomyces cerevisiae

    PubMed Central

    Kim, Hye-Jin; Kim, Hyang-Mi; Kim, Ji-Hye; Ryu, Kyeong-Seon; Park, Seung-Moon; Jahng, Kwang-Yeup; Yang, Moon-Sik; Kim, Dae-Hyuk

    2003-01-01

    Saccharomyces cerevisiae was engineered to express different amount of heavy (H)- and light (L)-chain subunits of human ferritin by using a low-copy integrative vector (YIp) and a high-copy episomal vector (YEp). In addition to pep4::HIS3 allele, the expression host strain was bred to have the selection markers leu2? and ura3? for YIplac128 and YEp352, respectively. The heterologous expression of phytase was used to determine the expression capability of the host strain. Expression in the new host strain (2805-a7) was as high as that in the parental strain (2805), which expresses high levels of several foreign genes. Following transformation, Northern and Western blot analyses demonstrated the expression of H- and L-chain genes. The recombinant yeast was more iron tolerant, in that transformed cells formed colonies on plates containing more than 25 mM ferric citrate, whereas none of the recipient strain cells did. Prussian blue staining indicated that the expressed isoferritins were assembled in vivo into a complex that bound iron. The expressed subunits showed a clear preference for the formation of heteropolymers over homopolymers. The molar ratio of H to L chains was estimated to be 1:6.8. The gel-purified heteropolymer took up iron faster than the L homopolymer, and it took up more iron than the H homopolymer did. The iron concentrations in transformants expressing the heteropolymer, L homopolymer, and H homopolymer were 1,004, 760, and 500 ?g per g (dry weight) of recombinant yeast cells, respectively. The results indicate that heterologously expressed H and L subunits coassemble into a heteropolymer in vivo and that the iron-carrying capacity of yeast is further enhanced by the expression of heteropolymeric isoferritin. PMID:12676675

  4. Fatal anaphylactic reaction to iron sucrose in pregnancy.

    PubMed

    Mishra, Ajay; Dave, Nikhil; Viradiya, Kishor

    2013-01-01

    Iron-deficiency anemia in pregnancy can have serious deleterious effects for both mother and fetus. Parenteral iron therapy in iron-deficiency anemia is recommended in patients where oral iron therapy is ineffective due to malabsorption states and non-compliance. Compared to oral iron therapy, intravenous iron results in much more rapid resolution of iron-deficiency anemia with minimal adverse reactions. Iron sucrose has a favorable safety profile and is an alternative to other forms of parenteral iron therapy in correction of iron stores depletion. Immune mechanisms and iron agent releasing bioactive, partially unbound iron into the circulation, resulting in oxidative stress appears to cause severe adverse reactions. Although iron sucrose has a favorable safety profile in comparison to other parenteral iron preparations, this report highlights a fatal anaphylactic shock to iron sucrose in a pregnant woman with severe iron deficiency non-compliant to oral iron therapy. PMID:23543624

  5. Fatal anaphylactic reaction to iron sucrose in pregnancy

    PubMed Central

    Mishra, Ajay; Dave, Nikhil; Viradiya, Kishor

    2013-01-01

    Iron-deficiency anemia in pregnancy can have serious deleterious effects for both mother and fetus. Parenteral iron therapy in iron-deficiency anemia is recommended in patients where oral iron therapy is ineffective due to malabsorption states and non-compliance. Compared to oral iron therapy, intravenous iron results in much more rapid resolution of iron-deficiency anemia with minimal adverse reactions. Iron sucrose has a favorable safety profile and is an alternative to other forms of parenteral iron therapy in correction of iron stores depletion. Immune mechanisms and iron agent releasing bioactive, partially unbound iron into the circulation, resulting in oxidative stress appears to cause severe adverse reactions. Although iron sucrose has a favorable safety profile in comparison to other parenteral iron preparations, this report highlights a fatal anaphylactic shock to iron sucrose in a pregnant woman with severe iron deficiency non-compliant to oral iron therapy. PMID:23543624

  6. A cascade of iron-containing proteins governs the genetic iron starvation response to promote iron uptake and inhibit iron storage in fission yeast.

    PubMed

    Encinar del Dedo, Javier; Gabrielli, Natalia; Carmona, Mercè; Ayté, José; Hidalgo, Elena

    2015-03-01

    Iron is an essential cofactor, but it is also toxic at high levels. In Schizosaccharomyces pombe, the sensor glutaredoxin Grx4 guides the activity of the repressors Php4 and Fep1 to mediate a complex transcriptional response to iron deprivation: activation of Php4 and inactivation of Fep1 leads to inhibition of iron usage/storage, and to promotion of iron import, respectively. However, the molecular events ruling the activity of this double-branched pathway remained elusive. We show here that Grx4 incorporates a glutathione-containing iron-sulfur cluster, alone or forming a heterodimer with the BolA-like protein Fra2. Our genetic study demonstrates that Grx4-Fra2, but not Fep1 nor Php4, participates not only in iron starvation signaling but also in iron-related aerobic metabolism. Iron-containing Grx4 binds and inactivates the Php4 repressor; upon iron deprivation, the cluster in Grx4 is probably disassembled, the proteins dissociate, and Php4 accumulates at the nucleus and represses iron consumption genes. Fep1 is also an iron-containing protein, and the tightly bound iron is required for transcriptional repression. Our data suggest that the cluster-containing Grx4-Fra2 heterodimer constitutively binds to Fep1, and upon iron deprivation the disassembly of the iron cluster between Grx4 and Fra2 promotes reverse metal transfer from Fep1 to Grx4-Fra2, and de-repression of iron-import genes. Our genetic and biochemical study demonstrates that the glutaredoxin Grx4 independently governs the Php4 and Fep1 repressors through metal transfer. Whereas iron loss from Grx4 seems to be sufficient to release Php4 and allow its nuclear accumulation, total or partial disassembly of the Grx4-Fra2 cluster actively participates in iron-containing Fep1 activation by sequestering its iron and decreasing its interaction with promoters. PMID:25806539

  7. A Systems Biology Approach to Iron Metabolism

    PubMed Central

    Chifman, J.; Laubenbacher, R.; Torti, S.V.

    2015-01-01

    Iron is critical to the survival of almost all living organisms. However, inappropriately low or high levels of iron are detrimental and contribute to a wide range of diseases. Recent advances in the study of iron metabolism have revealed multiple intricate pathways that are essential to the maintenance of iron homeostasis. Further, iron regulation involves processes at several scales, ranging from the subcellular to the organismal. This complexity makes a systems biology approach crucial, with its enabling technology of computational models based on a mathematical description of regulatory systems. Systems biology may represent a new strategy for understanding imbalances in iron metabolism and their underlying causes. PMID:25480643

  8. Metabolic crossroads of iron and copper

    PubMed Central

    Collins, James F; Prohaska, Joseph R; Knutson, Mitchell D

    2013-01-01

    Interactions between the essential dietary metals, iron and copper, have been known for many years. This review highlights recent advances in iron-copper interactions with a focus on tissues and cell types important for regulating whole-body iron and copper homeostasis. Cells that mediate dietary assimilation (enterocytes) and storage and distribution (hepatocytes) of iron and copper are considered, along with the principal users (erythroid cells) and recyclers of red cell iron (reticuloendothelial macrophages). Interactions between iron and copper in the brain are also discussed. Many unanswered questions regarding the role of these metals and their interactions in health and disease emerge from this synopsis, highlighting extensive future research opportunities. PMID:20384844

  9. Graphite Formation in Cast Iron

    NASA Technical Reports Server (NTRS)

    Stefanescu, D. M.

    1985-01-01

    In the first phase of the project it was proven that by changing the ratio between the thermal gradient and the growth rate for commercial cast iron samples solidifying in a Bridgman type furnace, it is possible to produce all types of graphite structures, from flake to spheroidal, and all types of matrices, from ferritic to white at a certain given level of cerium. KC-135 flight experiments have shown that in a low-gravity environment, no flotation occurs even in spheroidal graphite cast irons with carbon equivalent as high as 5%, while extensive graphite flotation occurred in both flake and spheroidal graphite cast irons, in high carbon samples solidified in a high gravity environment. This opens the way for production of iron-carbon composite materials, with high carbon content (e.g., 10%) in a low gravity environment. By using KC-135 flights, the influence of some basic elements on the solidification of cast iron will be studied. The mechanism of flake to spheroidal graphite transition will be studied, by using quenching experiments at both low and one gravity for different G/R ratios.

  10. Sonochemical synthesis of iron colloids

    SciTech Connect

    Suslick, K.S.; Fang, M.; Hyeon, T. [Univ. of Illinois, Urbana, IL (United States)] [Univ. of Illinois, Urbana, IL (United States)

    1996-11-27

    We present here a new method for the preparation of stable ferromagnetic colloids of iron using high-intensity ultrasound to sonochemically decompose volatile organometallic compounds. These colloids have narrow size distributions centered at a few nanometers and are found to be superparamagnetic. In conclusion, a simple synthetic method has been discovered to produce nanosized iron colloid using high-intensity ultrasound. Nanometer iron particles dispersed in polyvinylpyrrolidone (PVP) matrix or stabilized by adsorption of oleic acid have been synthesized by sonochemical decomposition of Fe(CO){sub 5}. Transmission electron micrographs show that the iron particles have a relatively narrow range in size from 3 to 8 nm for polyvinylpyrrolidone, while oleic acid gives an even more uniform distribution at 8 nm. magnetic measurements revealed that these nanometer iron particles are superparamagnetic with a saturation magnetization of 101 emu/g (Fe) at 290 K. This work is easily extended to colloids of other metals and to alloys of two or more metals, simply by using multiple volatile precursors. 29 refs., 4 figs.

  11. Iron in Parkinson's Disease Revisited

    NASA Astrophysics Data System (ADS)

    Galazka-Friedman, J.; Bauminger, E. R.; Friedman, A.

    2002-06-01

    Mössbauer studies of fresh frozen samples taken at autopsy from different parts of the human brain (globus pallidus (GP), substantia nigra (NS), and hippocamp (Hip)) showed a relatively high concentration of iron in these structures. Mössbauer data, biochemical results and transmission electron micrographs lead to the conclusion that in all above-mentioned structures iron is located mainly within ferritin. However, the Mössbauer doublets obtained from most brain samples at 90 K are slightly asymmetric. This asymmetry could be caused by the presence of a small amount of non-ferritin-like iron. Measurements at 4.1 K showed besides the six-line spectra characteristic for ferritin-like iron, an additional doublet with Mössbauer parameters different from ferritin. We found a slightly higher asymmetry and intensity of the 4.1 K doublet in Mössbauer spectra of Parkinsonian SN than in control SN. As Parkinson's disease is a progressive degeneration of nervous cells in SN and iron may be involved in this degeneration process, this may suggest that the factors evoking these phenomena are related to the pathogenesis of Parkinson's disease.

  12. Comparative study of iron mobilization from haemosiderin, ferritin and iron(III) precipitates by chelators.

    PubMed Central

    Kontoghiorghes, G J; Chambers, S; Hoffbrand, A V

    1987-01-01

    The heteroaromatic chelators 1,2-dimethyl-3-hydroxypyrid-4-one, maltol, mimosine and 2,4-dihydroxypyridine-N-oxide, have been shown to mobilize iron from human spleen haemosiderin, ferritin and also from iron(III) precipitates, all containing equal amounts of iron, at physiological pH. In the case of almost every chelator, the least-solubilized polynuclear iron form was ferritin, whereas haemosiderin was more soluble and the iron(III) precipitate the most soluble of all. Most of the chelators were more efficient than desferrioxamine at releasing iron from ferritin, but less efficient in the removal of iron from the other two polynuclear iron forms. It is suggested that the chelator differences in iron mobilization may be related to variations in the chelator molecular structure, the protein structure, iron forms and in the mechanism of iron release. PMID:3566714

  13. Measurement of hair iron concentration as a marker of body iron content

    PubMed Central

    SAHIN, CEM; PALA, CIGDEM; KAYNAR, LEYLAGUL; TORUN, YASEMIN ALTUNER; CETIN, AYSUN; KURNAZ, FATIH; SIVGIN, SERDAR; SAHIN, FATIH SERDAR

    2015-01-01

    The aim of the present study was to define the possible association between blood parameters and hair iron concentration in patient groups showing a difference in body iron content. The study population comprised subjects with iron deficiency anaemia and transfusion-related anaemia with different body iron contents and a healthy control group. All the cases included in the study were examined with respect to hair iron concentration, serum iron, total iron-binding capacity (TIBC), transferrin saturation and erythrocyte markers in the total blood count with ferritin values. Differences in hair iron concentration were evaluated between the groups. Correlation analysis was applied to define the association between the laboratory values used as markers of body iron content and hair iron concentration. A statistically significant difference was determined in hair iron 56Fe and 57Fe concentrations between the group with transfusion-related anaemia, the iron deficiency anaemia group and the healthy control group (P<0.001). In addition, a positive correlation was determined between hair iron 56Fe and 57Fe concentrations and serum iron, ferritin level, transferrin saturation, mean erythrocyte volume and mean erythrocyte haemoglobin values and a negative correlation with TIBC. In conclusion, the results of the present study showed a statistically significant difference in the hair iron concentrations of the patient groups with different body iron content and these values were correlated to the laboratory markers of body iron content. PMID:26137241

  14. Direct Biohydrometallurgical Extraction of Iron from Ore

    SciTech Connect

    T.C. Eisele

    2005-10-01

    A completely novel approach to iron extraction was investigated, based on reductive leaching of iron by anaerobic bacteria. Microorganisms were collected from an anaerobic bog where natural seepage of dissolved iron was observed. This mixed culture was used to reduce insoluble iron in a magnetite ore to the soluble ferrous (Fe{sup +2}) state. While dissolution rates were slow, concentrations of dissolved iron as high as 3487 mg/l could be reached if sufficient time was allowed. A factorial study of the effects of trace nutrients and different forms of organic matter indicated that the best dissolution rates and highest dissolved iron concentrations were achieved using soluble carbohydrate (sucrose) as the bacterial food source, and that nutrients other than nitrogen, phosphorus, potassium, sodium, and acetate were not necessary. A key factor in reaching high levels of dissolved iron was maintaining a high level of carbon dioxide in solution, since the solubility of iron carbonates increases markedly as the quantity of dissolved carbon dioxide increases. Once the iron is dissolved, it has been demonstrated that the ferrous iron can then be electroplated from solution, provided that the concentration of iron is sufficiently high and the hydrogen ion concentration is sufficiently low. However, if the leaching solution is electrolyzed directly, organic matter precipitates at the cathode along with the metallic iron. To prevent this problem, the ferrous iron should be separated from the bulk solution in a more concentrated, purified form. One route to accomplishing this is to take advantage of the change in solubility of ferrous iron as a function of carbon dioxide concentration. By cycling the concentration of carbon dioxide in solution, it is possible to produce an iron-rich concentrate that should be suitable for electrolysis. This represents the first viable hydrometallurgical method for leaching iron directly from ore and producing metallic iron.

  15. Antimicrobial properties of iron-binding proteins.

    PubMed

    Bezkorovainy, A

    1981-01-01

    The transferrins are iron-binding proteins with molecular weights of around 80,000, which interact with a maximum of two ferric atoms per each protein molecule. The best known transferrins are the serotransferrins from animal sera, lactoferrins from milk, and conalbumin from egg-white. The iron-deficient transferrins will inhibit the growth of certain bacteria and fungi by making iron unavailable for bacterial metabolism. Such activity is abolished if the transferrin is saturated with iron. Many organisms can produce small molecular-weight iron-binding compounds called siderophores that can successfully utilize the iron sequestered by the transferrins. Such organisms are very virulent. Overwhelming evidence is now available to indicate that the transferrins play an important role in mammalian host-defense mechanisms. Thus, iron injections into animals infected with virulent bacteria result in increased death rates, and parenteral iron administration to human infants predisposes them to fatal septicemia. On the other hand, in cases of systemic infection, the organism responds by lowering its total serum iron, so as to make the serotransferrin present less saturated with iron. This phenomenon is called nutritional immunity. The iron apparently moves into the storage tissues from the circulation, and furthermore, it is withheld from circulation by the reticuloendothelial system. Laboratory results in such cases indicate low total serum iron levels and high unsaturated iron-binding activity values, thus increasing the bacteriostatic effects of the serotransferrins. Increased lactoferrin levels are observed in the milks of mastitic cattle. PMID:6452038

  16. Salmonella Adhesion, Invasion and Cellular Immune Responses Are Differentially Affected by Iron Concentrations in a Combined In Vitro Gut Fermentation-Cell Model

    PubMed Central

    Dostal, Alexandra; Gagnon, Mélanie; Chassard, Christophe; Zimmermann, Michael Bruce; O'Mahony, Liam; Lacroix, Christophe

    2014-01-01

    In regions with a high infectious disease burden, concerns have been raised about the safety of iron supplementation because higher iron concentrations in the gut lumen may increase risk of enteropathogen infection. The aim of this study was to investigate interactions of the enteropathogen Salmonella enterica ssp. enterica Typhimurium with intestinal cells under different iron concentrations encountered in the gut lumen during iron deficiency and supplementation using an in vitro colonic fermentation system inoculated with immobilized child gut microbiota combined with Caco-2/HT29-MTX co-culture monolayers. Colonic fermentation effluents obtained during normal, low (chelation by 2,2'-dipyridyl) and high iron (26.5 mg iron/L) fermentation conditions containing Salmonella or pure Salmonella cultures with similar iron conditions were applied to cellular monolayers. Salmonella adhesion and invasion capacity, cellular integrity and immune response were assessed. Under high iron conditions in pure culture, Salmonella adhesion was 8-fold increased compared to normal iron conditions while invasion was not affected leading to decreased invasion efficiency (?86%). Moreover, cellular cytokines IL-1?, IL-6, IL-8 and TNF-? secretion as well as NF-?B activation in THP-1 cells were attenuated under high iron conditions. Low iron conditions in pure culture increased Salmonella invasion correlating with an increase in IL-8 release. In fermentation effluents, Salmonella adhesion was 12-fold and invasion was 428-fold reduced compared to pure culture. Salmonella in high iron fermentation effluents had decreased invasion efficiency (?77.1%) and cellular TNF-? release compared to normal iron effluent. The presence of commensal microbiota and bacterial metabolites in fermentation effluents reduced adhesion and invasion of Salmonella compared to pure culture highlighting the importance of the gut microbiota as a barrier during pathogen invasion. High iron concentrations as encountered in the gut lumen during iron supplementation attenuated Salmonella invasion efficiency and cellular immune response suggesting that high iron concentrations alone may not lead to an increased Salmonella invasion. PMID:24676135

  17. Di-iron-carboxylate proteins.

    PubMed

    Nordlund, P; Eklund, H

    1995-12-01

    Di-iron centers bridged by carboxylate residues and oxide/hydroxide groups have so far been seen in four classes of proteins involved in dioxygen chemistry or phosphoryl transfer reactions. The dinuclear iron centers in these proteins are coordinated by histidines and additional carboxylate ligands. Recent structural data on some of these enzymes, combined with spectroscopic and kinetic data, can now serve as a base for detailed mechanistic suggestions. The di-iron sites in the major class of hydroxylase-oxidase enzymes, which contains ribonucleotide reductase and methane monooxygenase, show significant flexibility in the geometry of their coordination of three or more carboxylate groups. This flexibility, combined with a relatively low coordination number, and a buried environment suitable for reactive oxygen chemistry, explains their efficient harnessing of the oxidation power of molecular oxygen. PMID:8749363

  18. [Iron overload and insulin resistance].

    PubMed

    Vantyghem, M-C; Girardot, C; Boulogne, A; Wemeau, J-L

    2005-11-01

    There is increasing evidence that moderately elevated body iron stores, below levels commonly found in genetic hemochromatosis, may be associated with adverse health outcomes. Genetic hemochromatosis, characterized by transferrin saturation (TS) greater than 45%, is most often linked to homozygosity of the HFE C282Y allele. The phenotype is also modulated by mutations of more recently discovered genes (including ferroportin, hemojuvelin, hepcidin, and transferrin receptor) and environmental factors (including alcohol, viruses, diet, blood loss). Iron overload without hemochromatosis is characterized by high levels of serum ferritin and normal TS, as seen in dysmetabolic hepatosiderosis. Elevated serum ferritin levels predict incident type 2 diabetes in prospective studies and have been associated with hypertension, dyslipidemia, glucose tolerance disturbances, central adiposity, and metabolic syndrome. High ferritin levels are not synonymous with iron overload and may in some cases be a simple marker of insulin resistance. PMID:16292193

  19. Facile and Sustainable Synthesis of Shaped Iron Oxide Nanoparticles: Effect of Iron Precursor Salts on the Shapes of Iron Oxides

    NASA Astrophysics Data System (ADS)

    Sayed, Farheen N.; Polshettiwar, Vivek

    2015-05-01

    A facile and sustainable protocol for synthesis of six different shaped iron oxides is developed. Notably, all the six shapes of iron oxides can be synthesised using exactly same synthetic protocol, by simply changing the precursor iron salts. Several of the synthesised shapes are not reported before. This novel protocol is relatively easy to implement and could contribute to overcome the challenge of obtaining various shaped iron oxides in economical and sustainable manner.

  20. Genes for iron metabolism influence circadian rhythms in Drosophila melanogaster.

    PubMed

    Mandilaras, Konstantinos; Missirlis, Fanis

    2012-08-01

    Haem has been previously implicated in the function of the circadian clock, but whether iron homeostasis is integrated with circadian rhythms is unknown. Here we describe an RNA interference (RNAi) screen using clock neurons of Drosophila melanogaster. RNAi is targeted to iron metabolism genes, including those involved in haem biosynthesis and degradation. The results indicate that Ferritin 2 Light Chain Homologue (Fer2LCH) is required for the circadian activity of flies kept in constant darkness. Oscillations of the core components in the molecular clock, PER and TIM, were also disrupted following Fer2LCH silencing. Other genes with a putative function in circadian biology include Transferrin-3, CG1358 (which has homology to the FLVCR haem export protein) and five genes implicated in iron-sulfur cluster biosynthesis: the Drosophila homologues of IscS (CG12264), IscU (CG9836), IscA1 (CG8198), Iba57 (CG8043) and Nubp2 (CG4858). Therefore, Drosophila genes involved in iron metabolism are required for a functional biological clock. PMID:22885802

  1. Disassembling Iron Availability to Phytoplankton

    PubMed Central

    Shaked, Yeala; Lis, Hagar

    2012-01-01

    The bioavailability of iron to microorganisms and its underlying mechanisms have far reaching repercussions to many natural systems and diverse fields of research, including ocean biogeochemistry, carbon cycling and climate, harmful algal blooms, soil and plant research, bioremediation, pathogenesis, and medicine. Within the framework of ocean sciences, short supply and restricted bioavailability of Fe to phytoplankton is thought to limit primary production and curtail atmospheric CO2 drawdown in vast ocean regions. Yet a clear-cut definition of bioavailability remains elusive, with elements of iron speciation and kinetics, phytoplankton physiology, light, temperature, and microbial interactions, to name a few, all intricately intertwined into this concept. Here, in a synthesis of published and new data, we attempt to disassemble the complex concept of iron bioavailability to phytoplankton by individually exploring some of its facets. We distinguish between the fundamentals of bioavailability – the acquisition of Fe-substrate by phytoplankton – and added levels of complexity involving interactions among organisms, iron, and ecosystem processes. We first examine how phytoplankton acquire free and organically bound iron, drawing attention to the pervasiveness of the reductive uptake pathway in both prokaryotic and eukaryotic autotrophs. Turning to acquisition rates, we propose to view the availability of various Fe-substrates to phytoplankton as a spectrum rather than an absolute “all or nothing.” We then demonstrate the use of uptake rate constants to make comparisons across different studies, organisms, Fe-compounds, and environments, and for gaging the contribution of various Fe-substrates to phytoplankton growth in situ. Last, we describe the influence of aquatic microorganisms on iron chemistry and fate by way of organic complexation and bio-mediated redox transformations and examine the bioavailability of these bio-modified Fe species. PMID:22529839

  2. Iron chelation and multiple sclerosis

    PubMed Central

    Weigel, Kelsey J.; Lynch, Sharon G.; LeVine, Steven M.

    2014-01-01

    Histochemical and MRI studies have demonstrated that MS (multiple sclerosis) patients have abnormal deposition of iron in both gray and white matter structures. Data is emerging indicating that this iron could partake in pathogenesis by various mechanisms, e.g., promoting the production of reactive oxygen species and enhancing the production of proinflammatory cytokines. Iron chelation therapy could be a viable strategy to block iron-related pathological events or it can confer cellular protection by stabilizing hypoxia inducible factor 1?, a transcription factor that normally responds to hypoxic conditions. Iron chelation has been shown to protect against disease progression and/or limit iron accumulation in some neurological disorders or their experimental models. Data from studies that administered a chelator to animals with experimental autoimmune encephalomyelitis, a model of MS, support the rationale for examining this treatment approach in MS. Preliminary clinical studies have been performed in MS patients using deferoxamine. Although some side effects were observed, the large majority of patients were able to tolerate the arduous administration regimen, i.e., 6–8 h of subcutaneous infusion, and all side effects resolved upon discontinuation of treatment. Importantly, these preliminary studies did not identify a disqualifying event for this experimental approach. More recently developed chelators, deferasirox and deferiprone, are more desirable for possible use in MS given their oral administration, and importantly, deferiprone can cross the blood–brain barrier. However, experiences from other conditions indicate that the potential for adverse events during chelation therapy necessitates close patient monitoring and a carefully considered administration regimen. PMID:24397846

  3. Toxicology and safety of Ferrochel and other iron amino acid chelates.

    PubMed

    Jeppsen, R B

    2001-03-01

    Iron is estimated to be deficient in the diets of one fifth of the world's population. Iron is commonly provided as a supplemental nutrient in industrialized countries for uses of choice. In other countries of the world, it may be required as an overt addition to the diet to prevent iron deficiency. This may be accomplished through fortification of a common food. As a micronutrient, iron has a relatively narrow range of safety--whether given as a supplement or fortificant, it must be in a high enough dose to be appreciably absorbed, but low enough to avoid toxicity. This concern can be ameliorated by careful choice of the form of iron administered. A source of iron which has proven to be highly bioavailable, yet regulated by dietary need, is iron chelated with amino acids. The structural integrity and longevity of these compounds have been proven by valid chemical and instrumental tests. Proofs of safety of iron amino acid chelate in the dietary administration of iron to swine in both multigenerational and longevity studies are reported. Formal tests of toxicity utilizing ferrous bisglycinate chelate (Ferrochel) carried out in accordance to US-FDA guidelines are also summarized. Ferrochel has been demonstrated to have a No Observable Adverse Effect Level (NOAEL) of at least 500 mg per kg rat body weight, the highest dose tested. This and other results of the detailed toxicity test, as well as other tests of safety and efficacy, have resulted in the US-FDA acknowledging that this product is Generally Recognized As Safe (GRAS) under its approved conditions of use as a source of iron for food enrichment and fortification purposes. PMID:11688078

  4. Influence of calcium depletion on iron-binding properties of milk.

    PubMed

    Mittal, V A; Ellis, A; Ye, A; Das, S; Singh, H

    2015-04-01

    We investigated the effects of calcium depletion on the binding of iron in milk. A weakly acidic cation-exchange resin was used to remove 3 different levels (18-22, 50-55, and 68-72%) of calcium from milk. Five levels of iron (5, 10, 15, 20, and 25 mM) were added to each of these calcium-depleted milks (CDM) and the resultant milks were analyzed for particle size, microstructure, and the distribution of protein and minerals between the colloidal and soluble phases. The depletion of calcium affected the distribution of protein and minerals in normal milk. Iron added to normal milk and low-CDM (~20% calcium depletion) bound mainly to the colloidal phase (material sedimented at 100,000×g for 1 h at 20°C), with little effect on the integrity of the casein micelles. Depletion of ~70% of the calcium from milk resulted in almost complete disintegration of the casein micelles, as indicated by all the protein remaining in the soluble phase upon ultracentrifugation. Addition of up to ~20 mM iron to high CDM resulted in the formation of small fibrous structures that remained in the soluble phase of milk. It appeared that the iron bound to soluble (nonsedimentable) caseins in high-CDM. We observed a decrease in the aqueous phosphorus content of all milks upon iron addition, irrespective of their calcium content. We considered the interaction between aqueous phosphorus and added iron to be responsible for the high iron-binding capacity of the proteins in milk. The soluble protein-iron complexes formed in high-CDM (~70% calcium depletion) could be used as an effective iron fortificant for a range of food products because of their good solubility characteristics. PMID:25648803

  5. Intervention strategies for improving iron status of young children and adolescents in India.

    PubMed

    Ahluwalia, Namanjeet

    2002-05-01

    Despite advances in scientific knowledge regarding multiple etiology, treatment, and potential strategies for combating iron deficiency and deficiencies of other micronutrients, iron deficiency anemia, vitamin A deficiency, and iodine deficiency remain significant public health challenges for growing children and adolescents. The short-term efficient supplementation approach, although technically feasible, has not been successful due to problems with delivery and compliance. Evidence is building that preventive supplementation coupled with nutrition education may be a more effective strategy associated with better compliance and improvement in iron status. Long-term, effective approaches include fortification, dietary modification, public health and disease control measures, and income generation programs. Food fortification can be a cost-effective intervention strategy if technologically feasible, nutritionally sound, culturally acceptable and economically viable food vehicle(s) and fortificant(s) can be identifed. Foods such as wheat, rice, and salt are commonly consumed in India; research is underway to evaluate various fortificants for these foods. Doubly fortified salt with iodine and iron may be particularly promising in the Indian situation as it is affordable, culturally acceptable, and may enhance iron absorption from Indian dietaries containing inhibitors of iron absorption. Feasibility studies are underway to evalute the stability and storage issues as well as bioavailability of fortificant iron. Dietary modification involves increased iron intake, by increasing total food intake and consumption of locally available iron-rich foods, and dietary practices favoring iron absorption. Blood loss associated with worm infestation can be controlled by periodic deworming and reducing reinfestation. Coordinating these major intervention approaches by building partnerships between the community, existing nutrition and health programs, government, industry, and academic institutions is critical for success of these programs. Nutrition education must be integral to all of these strategies discusssed. Primary health care system and school infrastructure and staff, along with school children and community members, can be powerful resources for addressing malnutrition in children and adolescents. PMID:12035848

  6. Complexed iron removal from groundwater

    SciTech Connect

    Munter, R.; Ojaste, H.; Sutt, J. [Tallinn Technical University, Tallinn (Estonia). Dept. of Environmental & Chemical Technology

    2005-07-01

    The paper demonstrates an intensive work carried out and results obtained on the pilot plant of the City of Kogalym Water Treatment Station (Tjumen, Siberia, Russian Federation) to elaborate on a contemporary nonreagent treatment technology for the local iron-rich groundwater. Several filter materials (Birm, Pyrolox, hydroanthracite, Everzit, granulated activated carbon) and chemical oxidants (ozone, chlorine, hydrogen peroxide, oxygen, and potassium permanganate) were tested to solve the problem with complexed iron removal from groundwater. The final elaborated technology consists of raw water intensive aeration in the gas-degas treatment unit followed by sequential filtration through hydroanthracite and the special anthracite Everzit.

  7. Ironing out the phosphorus problem.

    PubMed

    Zaritsky, Joshua J; Salusky, Isidro B

    2010-05-01

    Control of serum phosphorus remains a vexing problem in chronic kidney disease. Although novel dialysis regimens may provide excellent phosphorus control, phosphate binders remain necessary for most dialysis patients. Block et al. present a phase I clinical trial examining the safety and efficacy of SBR759, a novel non-calcium, iron-based phosphate binder. Although the risks of iron accumulation and hypocalcemia must be addressed, this phosphate binder appears to be well tolerated and effective and offers a powder-based formulation. PMID:20431575

  8. Selected properties of iron aluminides

    SciTech Connect

    Schneibel, J.H.

    1994-09-01

    Important properties of iron aluminides have been compiled in order to help engineers and scientists to be able to quickly assess this materials system. This compilation is by no means exhaustive, but it represents a reasonable first effort to summarize the properties of iron aluminides. Considerable care has been, used in assembling the data into tables. However, no guarantee can be made that all the values compiled here are correct; and in case of doubt, or in order to obtain more detailed information, the original sources should always be consulted.

  9. Association of iron with colorectal cancer.

    PubMed

    Weinberg, E D

    1994-07-01

    Many studies indicate that animals and humans burdened with excess iron are at increased risk of neoplasia at various sites. This review focuses on inquiries that involve iron and colorectal cancer. Relevant studies reported in the past decade are briefly described and evaluated. The studies in animal models and in relatively large groups of humans point to a positive association of excessive iron with colorectal oncogenesis. Phytic acid, a chelator of iron and zinc, may be useful in withholding iron from the carcinogenic process. Sufficient evidence is available to justify construction of long-term prospective studies in humans in which would be monitored (i) levels of iron and phytate intake, (ii) serum transferrin iron saturation and ferritin, (iii) fecal levels of iron and hydroxyl radicals, and (iv) appearance of colorectal polyps, adenomas and carcinomas. PMID:8043985

  10. Molecular mediators governing iron-copper interactions.

    PubMed

    Gulec, Sukru; Collins, James F

    2014-01-01

    Given their similar physiochemical properties, it is a logical postulate that iron and copper metabolism are intertwined. Indeed, iron-copper interactions were first documented over a century ago, but the homeostatic effects of one on the other has not been elucidated at a molecular level to date. Recent experimental work has, however, begun to provide mechanistic insight into how copper influences iron metabolism. During iron deficiency, elevated copper levels are observed in the intestinal mucosa, liver, and blood. Copper accumulation and/or redistribution within enterocytes may influence iron transport, and high hepatic copper may enhance biosynthesis of a circulating ferroxidase, which potentiates iron release from stores. Moreover, emerging evidence has documented direct effects of copper on the expression and activity of the iron-regulatory hormone hepcidin. This review summarizes current experimental work in this field, with a focus on molecular aspects of iron-copper interplay and how these interactions relate to various disease states. PMID:24995690

  11. Mechanisms of iron metabolism in Caenorhabditis elegans

    PubMed Central

    Anderson, Cole P.; Leibold, Elizabeth A.

    2014-01-01

    Iron is involved in many biological processes essential for sustaining life. In excess, iron is toxic due to its ability to catalyze the formation of free radicals that damage macromolecules. Organisms have developed specialized mechanisms to tightly regulate iron uptake, storage and efflux. Over the past decades, vertebrate model organisms have led to the identification of key genes and pathways that regulate systemic and cellular iron metabolism. This review provides an overview of iron metabolism in the roundworm Caenorhabditis elegans and highlights recent studies on the role of hypoxia and insulin signaling in the regulation of iron metabolism. Given that iron, hypoxia and insulin signaling pathways are evolutionarily conserved, C. elegans provides a genetic model organism that promises to provide new insights into mechanisms regulating mammalian iron metabolism. PMID:24904417

  12. Picqu et al Mechanical behaviour of iron oxide scale Mechanical behaviour of iron oxide scale

    E-print Network

    Paris-Sud XI, Université de

    of thick, brittle layers on metal substrates. Application is to the iron oxide behaviour during hot rolling or less thick iron oxide layer, hot rolling indeed consists in co-deforming a ceramic coating on a metalPicqué et al Mechanical behaviour of iron oxide scale 1 Mechanical behaviour of iron oxide scale

  13. Iron release from corroded iron pipes in drinkingwater distribution systems: effect of dissolved oxygen

    Microsoft Academic Search

    P. Sarina; V. L. Snoeyink; J. Bebee; K. K. Jim; W. M. Krivena Beckett; J. A. Clement

    Iron release from corroded iron pipes is the principal cause of ''colored water'' problems in drinkingwater distribution systems. The corrosion scales present in corroded iron pipes restrict the flow of water, and can also deteriorate the water quality. This research was focused on understandingthe effect of dissolved oxyg en (DO), a key water quality parameter, on iron release from the

  14. Increased iron (III) and total iron content in post mortem substantia nigra of parkinsonian brain

    Microsoft Academic Search

    E. Sofic; P. Riederer; H. Heinsen; H. Beckmann; G. P. Reynolds; G. Hebenstreit; M. B. H. Youdim

    1988-01-01

    Summary Significant differences in the content of iron (III) and total iron were found in post mortem substantia nigra of Parkinson's disease. There was an increase of 176% in the levels of total iron and 255% of iron (III) in the substantia nigra of the parkinsonian patients compared to age matched controls. In the cortex (Brodmann area 21), hippocampus, putamen,

  15. Liver iron stores in patients with secondary haemosiderosis under iron chelation therapy with deferoxamine or deferiprone.

    PubMed

    Nielsen, P; Fischer, R; Engelhardt, R; Tondüry, P; Gabbe, E E; Janka, G E

    1995-12-01

    Total body iron stores including liver and spleen iron were assessed by non-invasive SQUID biomagnetometry. The liver iron concentration was measured in groups of patients with beta-thalassaemia major or other posttransfusional siderosis under treatment with the oral iron chelator deferiprone (n = 19) and/or with parenteral deferoxamine (n = 33). An interquartile range for liver iron concentrations of 1680-4470 micrograms/g liver was found in these patients. In both groups a poor correlation between liver iron and serum ferritin values was observed. Repeated measurements of liver and spleen iron concentrations as well as determination of liver and spleen volume by sonography were performed in six patients under continuous deferiprone treatment for 3-15 months. In this group detailed information was obtained on the whole body iron store (5-36g) and the iron excretion rates (14-34 mg/d) for each patient. As indicated by decreasing liver iron concentrations, five out of six subjects showed a negative iron balance (2-13 mg/d). Conventional measurements of both serum ferritin and urine iron excretion gave fluctuating results, thus being only of limited use in the control of iron depletion therapy. The non-invasive biomagnetic liver iron quantification is a precise and clinically verified technique which offers more direct information on the long-term efficacy of an iron depletion therapy than the hitherto used methods. This technique may be of use in the clinical evaluation of new oral iron chelators. PMID:8547125

  16. The Iron-Iron Carbide Phase Diagram: A Practical Guide to Some Descriptive Solid State Chemistry.

    ERIC Educational Resources Information Center

    Long, Gary J.; Leighly, H. P., Jr.

    1982-01-01

    Discusses the solid state chemistry of iron and steel in terms of the iron-iron carbide phase diagram. Suggests that this is an excellent way of introducing the phase diagram (equilibrium diagram) to undergraduate students while at the same time introducing the descriptive solid state chemistry of iron and steel. (Author/JN)

  17. DOMAIN PATTERNS AND REVERSALS BY WALL MOVEMENTS OF THIN FILMS OF IRON AND NICKEL IRON

    E-print Network

    Paris-Sud XI, Université de

    310 DOMAIN PATTERNS AND REVERSALS BY WALL MOVEMENTS OF THIN FILMS OF IRON AND NICKEL IRON By C. E directions but in the case of the nickel-iron film the reversal of magnetization in the perpendicular domain reversals in nickel-iron films observed by the Kerr effect, and that of Williams and Sherwood [2

  18. Ironing Out the Wrinkles in Host Defense: Interactions between Iron Homeostasis and Innate Immunity

    Microsoft Academic Search

    Lijian Wang; Bobby J. Cherayil

    2009-01-01

    Iron is an essential micronutrient for both microbial pathogens and their mammalian hosts. Changes in iron availability and distribution have significant effects on pathogen virulence and on the immune response to infection. Recent advances in our understanding of the molecular regulation of iron metabolism have shed new light on how alterations in iron homeostasis both contribute to and influence innate

  19. The assessment of serum nontransferrin-bound iron in chelation therapy and iron supplementation

    Microsoft Academic Search

    William Breuer; Aharon Ronson; Itzchak N. Slotki; Ayala Abramov; Chaim Hershko; Z. Ioav

    Nontransferrin-bound iron (NTBI) ap- pears in the serum of individuals with iron overload and in a variety of other pathologic conditions. Because NTBI con- stitutes a labile form of iron, it might underlie some of the biologic damage associated with iron overload. We have developed a simple method for NTBI determination, which operates in a 96- well enzyme-linked immunosorbent as-

  20. Effect of iron chelators on placental uptake and transfer of iron in rat

    Microsoft Academic Search

    C. T. Wong; H. J. McArdle; E. H. Morgan

    1987-01-01

    The uptake of radiolabeled transferrin and iron by the rat placenta has been studied using two approaches. The first involved injection of a ferrous or ferric iron chelator followed by injection of label. Neither chelator decreased the amount of labelled transferrin in the placenta after 2-h incubation and only bipyridine, a ferrous iron chelator, inhibited iron transport to the fetus.

  1. An investigation of iron phosphate glasses

    Microsoft Academic Search

    Xiangyu Fang

    2000-01-01

    The effect of melting history on the iron redox equilibrium, structure, crystallization and properties of a binary iron phosphate glass with a 40Fe 2O3-60P2O5, mol%, batch composition were investigated. The structure and properties of single and mixed alkali iron phosphate glasses were also studied. Mossbauer, Raman and infrared spectroscopy were used to determine the changes in the concentration of iron

  2. What is new in iron overload?

    Microsoft Academic Search

    Christiane Vermylen

    2008-01-01

    Children with severe chronic hemolytic anemia or congenital erythroblastopenia are transfusion dependent. Long-term transfusion\\u000a therapy prolongs life but results in a toxic accumulation of iron in the organs. The human body cannot actively eliminate\\u000a excess iron. Therefore, the use of a chelating agent is required to promote excretion of iron. So far, iron chelation has\\u000a been done by subcutaneous infusion

  3. Thermal fracture endurance of cast irons with application study of pig iron ingot molds

    NASA Astrophysics Data System (ADS)

    Lee, Jye-Long; Lee, Shen-Chih

    1995-06-01

    Pig iron ingot molds manufactured with flake, compacted graphite cast iron, and spheroidal graphite cast iron were installed on a pig iron casting machine and subjected to thermal cycling for studying thermal fracture endurance of the three cast irons. The effects of graphite morphology on the fracture mechanism were analyzed by examining the fracture patterns, microstructures, and microcracks in the failed molds. The determining factors of thermal fracture endurance were elucidated with thermal fracture resistance indices. Compacted graphite cast iron exhibited better thermal fracture endurance than flake and spheroidal graphite cast irons because of its higher strength-to-thermal stress ratio.

  4. The role of hippocampal iron concentration and hippocampal volume in age-related differences in memory.

    PubMed

    Rodrigue, Karen M; Daugherty, Ana M; Haacke, E Mark; Raz, Naftali

    2013-07-01

    The goal of this study was to examine the relationships between 2 age-sensitive indices of brain integrity--volume and iron concentration--and the associated age differences in memory performance. In 113 healthy adults (age 19-83 years), we measured the volume and estimated iron concentration in the hippocampus (HC), caudate nucleus (Cd), and primary visual cortex (VC) in vivo with T2* relaxation times, and assessed memory performance with multiple tests. We applied structural equation modeling to evaluate the contribution of individual differences in 2 indices of integrity, volume and T2*, to age-related memory variance. The results show that in healthy adults, age differences in memory can be explained in part by individual differences in HC volume that in turn are associated with differences in HC iron concentration. Lower memory scores were linked to smaller HC and higher HC iron concentration. No such associations were noted for Cd and VC. We conclude that the association between age-related declines in memory and reduced hippocampal volume may reflect the impact of oxidative stress related to increase in free iron concentration. Longitudinal follow-up is needed to test whether altered iron homeostasis in the HC is an early marker for age-related cognitive decline. PMID:22645251

  5. 4, 44114441, 2007 iron-fertilization

    E-print Network

    Paris-Sud XI, Université de

    Influences of initial plankton biomass and mixed layer depths on the outcome of iron of the model results to the5 mixed layer depths reveals that the modeled response to the same iron enhancement treatment differed dramatically according to the different mixed layer depth. The mag- nitude of the iron

  6. Electrolytic Corrosion of Iron and Copper

    Microsoft Academic Search

    W. F. Higgins

    1954-01-01

    IT is generally accepted that if cast iron and copper are coupled together in a brine solution, the iron, being the less noble member, is likely to suffer corrosion. The copper, on the other hand, will be made `more negative' by contact with the iron and will be prevented in greater or less degree from corroding. The classical work on

  7. Iron sulfide deposition during coal gasification

    Microsoft Academic Search

    D. Duane Brooker; Myongsook S. Oh

    1995-01-01

    Previous analysis of ash generated during coal gasification using a high calcium coal (SUFCo) suggested that iron sulfide was the dominant sulfide species in the system. During a recent analysis of ash material removed from a gasification pilot unit using Pittsburgh No. 8, a high iron coal, sub-?m to 5 ?m euhedral iron sulfide crystals were identified on the outer

  8. The Ins and Outs of Iron Homeostasis

    NSDL National Science Digital Library

    Adriana Donovan (Harvard Medical School, ChildrenÂ?s Hospital Boston, Dana-Farber Cancer Institute)

    2006-04-01

    Iron is an essential element that is toxic when it accumulates in excess. Intricate regulatory mechanisms have evolved to maintain iron homeostasis within cells and between different tissues of complex organisms. This review discusses the proteins involved in iron transport and storage and their regulation in health and disease.

  9. 4, 249275, 2007 Effects of iron on

    E-print Network

    Paris-Sud XI, Université de

    BGD 4, 249­275, 2007 Effects of iron on diatom stoichiometry L. J. Hoffmann et al. Title Page of iron on the elemental stoichiometry during EIFEX and in the diatoms Fragilariopsis kerguelensis #12;BGD 4, 249­275, 2007 Effects of iron on diatom stoichiometry L. J. Hoffmann et al. Title Page

  10. Iron Homeostasis, Oxidative Stress, and DNA Damage

    Microsoft Academic Search

    Rogerio Meneghini

    1997-01-01

    Cellular DNA damage under prooxidant conditions has been shown to be mediated by iron. In fact, iron is an important element in the establishment of a prooxidant status in the cell. It is discussed that there exists a mutual dependence between iron metabolism and oxidative stress. Changes in the former by means of genetic manipulation bring about modification in the

  11. Marine Siderophores and Microbial Iron Mobilization

    Microsoft Academic Search

    Alison Butler

    2005-01-01

    Iron is essential for the growth of nearly all microorganisms yet iron is only sparingly soluble near the neutral pH, aerobic conditions in which many microorganisms grow. The pH of ocean water is even higher, thereby further lowering the concentration of dissolved ferric ion. To compound the problem of availability, the total iron concentration is surprisingly low in surface ocean

  12. Iron in biology: a structural viewpoint

    Microsoft Academic Search

    Peter F. Lindley

    1996-01-01

    The element iron is essential for life and plays a number of key roles in biology. For example, iron is the most abundant metal in humans with healthy adults possessing some 3 to 4 g. The bulk of this iron is bound to the oxygen transporting haemoglobin in the red blood corpuscles, to the muscle oxygen storage protein myoglobin, or

  13. Iron Deficiency in Autism and Asperger Syndrome.

    ERIC Educational Resources Information Center

    Latif, A.; Heinz, P.; Cook, R.

    2002-01-01

    Retrospective analysis of the full blood count and, when available, serum ferritin measurements of 96 children (52 with autism and 44 with Asperger syndrome) found six autistic children had iron deficiency and 12 of the 23 autistic children with serum ferritin measures were iron deficient. Far fewer Asperger children were iron deficient. Results…

  14. [Effect of iron on Pasteurella multocida].

    PubMed

    Flossmann, K D; Müller, G; Heilmann, P; Rosner, H

    1984-10-01

    Iron is an important factor for growth, virulence and immunogenicity of the species Pasteurella multocida. This has been demonstrated in numerous experiments with bacterial cultures in vitro and immunized and not immunized animals in vivo (mice, piglets, calves). Iron substrates or iron chelators affect in different manner the virulence of P. multocida in vivo, depending on chemical character of the given compounds, their dose, route and time of application, and also depending on the host. P. multocida has an up to time unknown iron transport system, which can acquire the essential iron from physiological substances, such as heme, ferritine, transferrine, lactoferrine etc. This conclusion results from in vitro experiments with growing cultures, with insertion of radioactive iron (Fe-59) from different sources, and with iron solubilization in neutral pH ranges. In the same way, the iron of iron dextran and low molecular iron compounds is available for P. multocida. Iron of unphysiological complexes, potassium ferrocyanide, and ferrocene is unavailable. On the other side such iron chelating agents as nitrilotriacetate, tirone, ferrocene, citrate, EDTA, and apotransferrine do not or only a little affect growth, and such chelators as alpha, alpha'-dipyridyle, phenanthroline and the microbial siderophores deferrioxamin B and enterobactin are inhibitory substances for multiplication of P. multocida. This substances also inhibit the insertion of Fe-59 into the bacterial cell. The conclusion is drawn that neither enterobactin nor deferrioxamine B as typical representatives of phenolate or hydroxamate siderophores take part in Fe-transport of P. multocida. PMID:6524157

  15. Fate of blood meal iron in mosquitoes.

    PubMed

    Zhou, Guoli; Kohlhepp, Pete; Geiser, Dawn; Frasquillo, Maria Del Carmen; Vazquez-Moreno, Luz; Winzerling, Joy J

    2007-11-01

    Iron is an essential element of living cells and organisms as a component of numerous metabolic pathways. Hemoglobin and ferric-transferrin in vertebrate host blood are the two major iron sources for female mosquitoes. We used inductively coupled plasma mass spectrometry (ICP-MS) and radioisotope labeling to quantify the fate of iron supplied from hemoglobin or as transferrin in Aedes aegypti. At the end of the first gonotrophic cycle, approximately 87% of the ingested total meal heme iron was excreted, while 7% was distributed into the eggs and 6% was stored in different tissues. In contrast, approximately 8% of the iron provided as transferrin was excreted and of that absorbed, 77% was allocated to the eggs and 15% distributed in the tissues. Further analyses indicate that of the iron supplied in a blood meal, approximately 7% appears in the eggs and of this iron 98% is from hemoglobin and 2% from ferric-transferrin. Whereas, of iron from a blood meal retained in body of the female, approximately 97% is from heme and <1% is from transferrin. Evaluation of iron-binding proteins in hemolymph and egg following intake of (59)Fe-transferrin revealed that ferritin is iron loaded in these animals, and indicate that this protein plays a critical role in meal iron transport and iron storage in eggs in A. aegypti. PMID:17689557

  16. Iron-Deficient Erythropoiesis in Neonatal Rats

    Microsoft Academic Search

    Suzanne H. Dubuque; Bohuslav Dvorak; Suann S. Woodward; Robert S. McCuskey; Pamela J. Kling

    2002-01-01

    Anemia in premature infants is extremely common. Precise quantitation of iron status and determination of iron incorporation into erythrocytes are important in monitoring therapy for anemia in premature infants, especially when treating with recombinant human erythropoietin (rhEPO). However, the traditional indices of the iron status have limited usefulness in this population. The goal of the current work is to develop

  17. ANEMIA OF DISORDERED IRON METABOLISM AND HEME

    E-print Network

    9/16/2013 1 ANEMIA OF DISORDERED IRON METABOLISM AND HEME SYNTHESIS Defect in Heme Synthesis Defect Deficiency Anemia Sideroachristic ­ adequate iron but defective utilization Sideroblastic Anemia Anemia;9/16/2013 4 IRON DEFICIENCY ANEMIA CAUSES Dietary Deficiency Blood Loss Hemodialysis Malabsorption IDA

  18. 21 CFR 522.1182 - Iron injection.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...i) For prevention of iron deficiency anemia, inject 100 mg (1 mL) by intramuscular...ii) For treatment of iron deficiency anemia, inject 100 mg (1 mL) by intramuscular...follows: (i) For the prevention of anemia due to iron deficiency,...

  19. 21 CFR 522.1182 - Iron injection.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...i) For prevention of iron deficiency anemia, inject 100 mg (1 mL) by intramuscular...ii) For treatment of iron deficiency anemia, inject 100 mg (1 mL) by intramuscular...follows: (i) For the prevention of anemia due to iron deficiency,...

  20. 21 CFR 522.1182 - Iron injection.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...i) For prevention of iron deficiency anemia, inject 100 mg (1 mL) by intramuscular...ii) For treatment of iron deficiency anemia, inject 100 mg (1 mL) by intramuscular...follows: (i) For the prevention of anemia due to iron deficiency,...

  1. 21 CFR 522.1182 - Iron injection.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...i) For prevention of iron deficiency anemia, inject 100 mg (1 mL) by intramuscular...ii) For treatment of iron deficiency anemia, inject 100 mg (1 mL) by intramuscular...follows: (i) For the prevention of anemia due to iron deficiency,...

  2. Physics of Iron at Earth's Core Conditions

    Microsoft Academic Search

    A. Laio; S. Bernard; G. L. Chiarotti; S. Scandolo; E. Tosatti

    2000-01-01

    The bulk properties of iron at the pressure and temperature conditions of Earth's core were determined by a method that combines first-principles and classical molecular dynamic simulations. The theory indicates that (i) the iron melting temperature at inner-core boundary (ICB) pressure (330 gigapascals) is 5400 (+\\/-400) kelvin; (ii) liquid iron at ICB conditions is about 6% denser than Earth's outer

  3. Ligand iron catalysts for selective hydrogenation

    Microsoft Academic Search

    Charles P. Casey; Hairong Guan

    2010-01-01

    Disclosed are iron ligand catalysts for selective hydrogenation of aldehydes, ketones and imines. A catalyst such as dicarbonyl iron hydride hydroxycyclopentadiene) complex uses the OH on the five member ring and hydrogen linked to the iron to facilitate hydrogenation reactions, particularly in the presence of hydrogen gas.

  4. Ligand iron catalysts for selective hydrogenation

    DOEpatents

    Casey, Charles P. (Madison, WI); Guan, Hairong (Cincinnati, OH)

    2010-11-16

    Disclosed are iron ligand catalysts for selective hydrogenation of aldehydes, ketones and imines. A catalyst such as dicarbonyl iron hydride hydroxycyclopentadiene) complex uses the OH on the five member ring and hydrogen linked to the iron to facilitate hydrogenation reactions, particularly in the presence of hydrogen gas.

  5. Iron isotope fractionation between liquid and vapor phases of iron pentacarbonyl.

    PubMed

    Wiesli, René A; Beard, Brian L; Braterman, Paul S; Johnson, Clark M; Saha, Susanta K; Sinha, Mahadeva P

    2007-01-15

    Iron isotope fractionation between liquid and vapor iron pentacarbonyl was measured in a closed system at approximately 0 and approximately 21 degrees C to determine if Fe isotope analysis of iron pentacarbonyl vapor is viable using electron-impact, gas-source mass spectrometry. At the 2sigma level, there is no significant Fe isotope fractionation between vapor and liquid under conditions thought to reflect equilibrium. Experiments at approximately 0 degrees C indicate iron pentacarbonyl vapor is approximately 0.05 per mil (per thousand) greater in (56)Fe/(54)Fe than liquid iron pentacarbonyl, which is just resolvable at the 1sigma level. Partial decomposition of iron pentacarbonyl vapor or liquid to an iron oxide or iron metal shows that significant isotopic fractionation occurs, where the decomposed product has a lower (56)Fe/(54)Fe ratio as compared to the starting iron pentacarbonyl. It follows that methods to decompose iron pentacarbonyl must be quantitative to obtain accurate isotope values. PMID:19071272

  6. Electron Spectroscopy Studies of Iron, Iron Sulfides and Supported Iron Surfaces: Chemisorption of Simple Gases.

    NASA Astrophysics Data System (ADS)

    Lee, Yiu Chung

    EELS was used to investigate the chemisorption of oxygen and carbon on iron. The EELS spectra of oxidized iron show characteristic features with strong enhancement of the interband transitions involving the Fe 3d band (4.6 and 7.5 eV) and moderate enhancement of the M(,2,3) transition doublet (54.4 and 58.2 eV). The changes in the electron energy loss structures with an overlayer of graphitic or carbidic carbon were investigated. The adsorption and growth of iron on Ni(100) has been studied using the combined techniques of LEED and EELS. Initially iron grows by a layer-by-layer mechanism for the first few layers. High iron coverages result in the observation of complex LEED patterns with satellites around the main (1 x 1) diffraction sports. This is due to the formation of b.c.c. Fe(110) crystallites arranged in domains with different orientations. EELS studies show the presence of three stages in the growth of iron on Ni(100): low-coverage, film-like and bulk-like. Auger and EELS were used to study the iron sulfide (FeS(,2), Fe(,7)S(,8) and FeS) surfaces. A characteristic M(,2,3) VV Auger doublet with a separation of 5.0 eV was observed on the sulfides. An assignment of the electron energy loss peaks was made based on the energy dependence of the loss peaks and previous photoemission results. The effect of argon ion bombardment was studied. Peaks with strong iron and sulfur character were observed. Heating the damaged sulfides results in reconstruction of the sulfide surfaces. The reactions of the sulfides with simple gases, such as H(,2), CO, CH(,4), C(,2)H(,4), NH(,3) and O(,2) were also studied. Using XPS, the chemisorption of SO(,2) on CaO(100) has been studied. The chemical state of sulfur has been identified as that of sulfate. The kinetics of SO(,2) chemisorption on CaO are discussed. The binding states of Fe and Na on CaO were determined to be Fe('2+) and Na('+) respectively. At low Fe or Na coverages (< 0.5 ML), there is a large increase in the rate of sulfate formation at low SO(,2) exposures (< 3 L). This increase is explained by the 'activation' of SO(,2) chemisorption sites by Fe or Na adatoms.

  7. Progressive hair straightening using an automated flat iron: function of silicones.

    PubMed

    Dussaud, Anne; Rana, Bhavna; Lam, Hui Tung

    2013-01-01

    An automated hair iron was built with which the hair temperature, contact force of the iron against the hair tress, and gliding speed were controlled. The changes in keratin were characterized by several techniques including differential scanning calorimetry, birefringence measurements, and wet tensile tests. Undamaged curly hair was ironed for several iron cycles at temperatures ranging from 120°C to 175°C and washed between each iron cycle. Irreversible straightening of curly hair was observed and depended on the temperature and the number of cycles. The birefringence data suggested that the straightening was related to a gradual decrease of the microfilament organization. Silicone treatment did not significantly affect the course of microfilament denaturation, but it improved the quality of straightening. It enhanced the fiber alignment under the gliding action of the iron. Progressive thermal straightening may be a promising method to achieve permanent smoothing of curly hair without chemical treatment. Ironing at the onset temperature (?154°C), before substantial disulfide bond scission occurred, seemed to be a good compromise between process speed, straightening performance, and hair integrity (i.e., reduced loss of cross-linking). PMID:23578835

  8. Redox Chemistry of Iron in Multiphase Atmosphere.

    NASA Astrophysics Data System (ADS)

    Pehkonen, Simo Olavi

    1995-01-01

    Iron redox chemistry was investigated in fog and stratus clouds in urban and remote locations in California, Delaware and New York. It was observed that iron(II) contributed from 20 to 70% of the total iron in the samples and that iron(III) was bound mostly as oxalato complexes in most samples. The iron(II) oxidation state seemed to correlate best with organic compounds, i.e., carboxylic acids and TOC (total organic carbon), indicating the important role of organic compounds to the redox state of iron. A new spectrophotometric technique for measuring simultaneously iron(II) and iron(III) in atmospheric water samples real time in the field was developed. DPKBH (Di -2-pyridyl ketone benzoylhydrazone) forms complexes with both iron(II) and iron(III) with an absorption maximum at 375 nm for both iron(II)-DPKBH and iron(III)-DPKBH and an absorption maximum at 660 nm for iron(II)-DPKBH. The detection limit of this method is 4 nM of iron with chloroform -water extraction and 0.1 ?m without the extraction. DPKBH forms bis complexes with iron and binds via the oxygen and two nitrogen atoms of the enol form of DPKBH as indicated by a FTIR study of the iron(III) -DPKBH complex. In addition to field observations, complementary laboratory photoreduction experiments were carried out with a variety of iron oxides and a variety of important atmospheric organic compounds such as oxalate, formate, acetate and formaldehyde. Photoreduction of am-Fe(OH) _3 with formate yielded the highest rates of photoreduction. Stability of the iron oxide and the strength of Fe-O bonds in the lattice played a more important role in the rate of iron photoreduction than the reactive surface area. Hydrogen peroxide was produced in the case of oxalate as the electron donor. Additional iron photoreduction experiments were carried out with halogenated acetic acids (the end products of tropospheric HCFC degradation) as electron donors and it was observed that monohalo acetic acids reduce iron oxides faster and get photooxidized faster compared to acetic acid.

  9. Minimizing iron and copper deposition

    Microsoft Academic Search

    1975-01-01

    A major cause of tube failures in high-pressure subcritical boilers is uncontrolled deposition of corrosion products in internal tube surfaces. The predominant corrosion products are iron oxides, copper, and copper oxides. A water treatment program that controls corrosion products can increase availability and reliability by reducing tube failures and acid cleaning frequency. Such a program includes corrosion product dispersion in

  10. Fuel compositions containing iron pentacarbonyl

    Microsoft Academic Search

    Hinkamp

    1982-01-01

    An improved fuel composition comprising a major amount of hydrocarbons boiling in the gasoline boiling range, and a minor amount of iron pentacarbonyl capable of improving the octane number rating of the composition but insufficient to cause excessive wear in engine parts when the fuel composition is burned in an internal combustion engine.

  11. Fuel compositions containing iron pentacarbonyl

    SciTech Connect

    Hinkamp, J.B.

    1982-06-22

    An improved fuel composition comprising a major amount of hydrocarbons boiling in the gasoline boiling range, and a minor amount of iron pentacarbonyl capable of improving the octane number rating of the composition but insufficient to cause excessive wear in engine parts when the fuel composition is burned in an internal combustion engine.

  12. FUGITIVE EMISSIONS FROM IRON FOUNDRIES

    EPA Science Inventory

    The report describes the assessment of fugitive emissions of air pollutants discharged from process operations in iron foundries, and the need for the development of control technology for the most critical sources. Data indicates that the most significant fugitive emissions cont...

  13. Ironing out a midlife crisis.

    PubMed

    Vergara, Sandra Viviana; Thiele, Dennis J

    2009-06-26

    There is a strong correlation between age, genomic instability, and the development of cancer. Working in yeast, Veatch et al. (2009) now propose that defects in the biogenesis of iron-sulfur clusters arising as a consequence of mitochondrial dysfunction contribute to the increase in genomic instability as cells age. PMID:19563748

  14. Dynamic transition in supercritical iron.

    PubMed

    Fomin, Yu D; Ryzhov, V N; Tsiok, E N; Brazhkin, V V; Trachenko, K

    2014-01-01

    Recent advance in understanding the supercritical state posits the existence of a new line above the critical point separating two physically distinct states of matter: rigid liquid and non-rigid gas-like fluid. The location of this line, the Frenkel line, remains unknown for important real systems. Here, we map the Frenkel line on the phase diagram of supercritical iron using molecular dynamics simulations. On the basis of our data, we propose a general recipe to locate the Frenkel line for any system, the recipe that importantly does not involve system-specific detailed calculations and relies on the knowledge of the melting line only. We further discuss the relationship between the Frenkel line and the metal-insulator transition in supercritical liquid metals. Our results enable predicting the state of supercritical iron in several conditions of interest. In particular, we predict that liquid iron in the Jupiter core is in the "rigid liquid" state and is highly conducting. We finally analyse the evolution of iron conductivity in the core of smaller planets such as Earth and Venus as well as exoplanets: as planets cool off, the supercritical core undergoes the transition to the rigid-liquid conducting state at the Frenkel line. PMID:25424664

  15. Dynamic transition in supercritical iron

    PubMed Central

    Fomin, Yu. D.; Ryzhov, V. N.; Tsiok, E. N.; Brazhkin, V. V.; Trachenko, K.

    2014-01-01

    Recent advance in understanding the supercritical state posits the existence of a new line above the critical point separating two physically distinct states of matter: rigid liquid and non-rigid gas-like fluid. The location of this line, the Frenkel line, remains unknown for important real systems. Here, we map the Frenkel line on the phase diagram of supercritical iron using molecular dynamics simulations. On the basis of our data, we propose a general recipe to locate the Frenkel line for any system, the recipe that importantly does not involve system-specific detailed calculations and relies on the knowledge of the melting line only. We further discuss the relationship between the Frenkel line and the metal-insulator transition in supercritical liquid metals. Our results enable predicting the state of supercritical iron in several conditions of interest. In particular, we predict that liquid iron in the Jupiter core is in the “rigid liquid” state and is highly conducting. We finally analyse the evolution of iron conductivity in the core of smaller planets such as Earth and Venus as well as exoplanets: as planets cool off, the supercritical core undergoes the transition to the rigid-liquid conducting state at the Frenkel line. PMID:25424664

  16. SYNTHESIS OF IRON-GERMANIUM

    E-print Network

    Baltisberger, Jay H.

    SYNTHESIS OF IRON-GERMANIUM Summer Research 2010 Rohan Isaac Advisor: Dr. Amer Lahamer #12;What in solid state devices. Can create completely spin polarized current. #12;Synthesis Mix stoichiometric. Under vacuum or flow of argon (inert gas) so that materials only react with each other

  17. Coal desulfurization with iron pentacarbonyl

    NASA Technical Reports Server (NTRS)

    Hsu, G. C.

    1979-01-01

    Coal desulfurization with iron pentacarbonyl treatment under mild conditions removes up to eighty percent of organic sulfur. Preliminary tests on treatment process suggest it may be economical enough to encourage investigation of use for coal desulfurization. With mild operating conditions, process produces environmentally-acceptable clean coal at reasonable cost.

  18. CCMR: Environmentally Benign Iron Catalysts

    NSDL National Science Digital Library

    Brown, Kristi L.

    2007-08-29

    A new para substituted iPrPDI ligand was synthesized using methods previously described1. iPrPDI-CH2TMS, a bright yellow solid was isolated in moderate yields. An iron catalyst, iPrPDI-(CH2TMS)FeBr2 was synthesized and tested in a polymerization reaction with preliminary success.

  19. ENVIRONMENTAL ASSESSMENT OF IRON CASTING

    EPA Science Inventory

    Sampling of ductile iron casting in green sand molds with phenolic isocyanate cores and in phenol-formaldehyde bound shell molds did not provide definitive proof that environmentally hazardous organic emission occur. Both molding systems produced the same type of major emissions,...

  20. Ironing out the wrinkles in host defense: interactions between iron homeostasis and innate immunity.

    PubMed

    Wang, Lijian; Cherayil, Bobby J

    2009-01-01

    Iron is an essential micronutrient for both microbial pathogens and their mammalian hosts. Changes in iron availability and distribution have significant effects on pathogen virulence and on the immune response to infection. Recent advances in our understanding of the molecular regulation of iron metabolism have shed new light on how alterations in iron homeostasis both contribute to and influence innate immunity. In this article, we review what is currently known about the role of iron in the response to infection. PMID:20375603

  1. Iron-limited growth and kinetics of iron uptake in Magnetospirillum gryphiswaldense

    Microsoft Academic Search

    Dirk Schüler; Edmund Baeuerlein

    1996-01-01

    Growth and magnetite formation in Magnetospirillum gryphiswaldense MSR-1 were found close to the maximum at an extracellular iron concentration of 15–20 ?M. Ferrous iron was incorporated by\\u000a a slow, diffusion-like process. Several iron chelators including various microbial siderophores were unable to promote transport\\u000a of iron into the cells. In contrast, spent culture fluids stimulated the uptake of ferric iron in

  2. Commentary: Iron deficiency and hair loss: problems with measurement of iron.

    PubMed

    Elston, Dirk M

    2010-12-01

    Iron is involved in many critical physiologic processes within the hair follicle, suggesting that iron deficiency could disrupt hair synthesis. However, studies of iron as a cause of hair loss have produced conflicting results. Some of the discrepancies may relate to limitations of assays for iron deficiency. This commentary discusses the sensitivity and specificity of available tests for iron deficiency and presents practical guidelines for testing and supplementation. PMID:20888066

  3. Formation of IIAB iron meteorites

    NASA Astrophysics Data System (ADS)

    Wasson, John T.; Huber, Heinz; Malvin, Daniel J.

    2007-02-01

    Group IIAB is the third largest group of iron meteorites and the second largest group that formed by fractional crystallization; many of these irons formed from the P-rich portion of a magma consisting of two-immiscible liquids. We report neutron-activation data for 78 IIAB irons. These confirm earlier studies showing that the group has the largest known range in Ir concentrations (a factor of 4000) and that slopes are steeply negative on plots of Ir vs. Au or As (or Ni). High negative slopes imply relatively high distribution coefficients for Ir, Au, and As (but, with rare exceptions, remaining less than unity for the latter). IIAB appears to have had the highest S contents of any magmatic group of iron meteorites, consistent with its high contents of other volatile siderophiles, particularly Ga and Ge. Large fractions of trapped melt were present in the IIAB irons with the highest Au and As and lowest Ir contents. As a result, when these irons crystallized, the DAu and DAs values can, with moderate accuracy, be estimated to have been roughly 0.53 and 0.46, respectively. These low values imply that the initial nonmetal (S + P) content of the magma was much lower than 170 mg/g, as estimated in earlier studies; our estimate is 75 mg/g. Our results are consistent with an initial P/S ratio of 0.25, similar to the ratio estimated for other magmatic groups. There is little doubt that incompatible S-rich and P-rich metallic liquids were involved during the formation of group IIAB. After 20% crystallization of our assumed starting composition the two-liquid boundary is encountered (at 72 mg/g S and 18 mg/g P). Initially the volume of S-rich liquid is very small, but continued crystallization increased the volume of this phase and decreased its P/S ratio while increasing this ratio in the P-rich liquid. Most crystallization of the IIAB magma would have occurred in the lower, P-rich portion of the core. However, metal was still a liquidus phase at the top of the core and, because both the immiscible liquids would have convected, they may have approached equilibrium throughout the very limited crystallization of the magma recorded in group IIAB. All IIAB irons contain trapped melt, and this melt will have had very different compositions depending on whether the liquid is S-rich (at the outer solid/liquid interface) or P-rich (at the inner interface). The P/S ratio in the melt trapped in the Santa Luzia iron is about 0.6 g/g, consistent with our modeling of Ir-Au and Ir-As trends implying that Santa Luzia formed in the lower, P-rich portion of the core after about 48% crystallization of the magma. Because the liquids were in equilibrium, the point at which immiscibility first occurred is not recorded by a dramatic change in the trends on element-Au diagrams; the main compositional effect is recorded in the P/S ratio of the trapped melt. The high-Au (>0.8 ?g/g) irons for which large sections are available all contain skeletal schreibersite implying a relatively high (>0.3 g/g) P/S ratio; none of these irons could have crystallized from the S-rich upper layer of the core.

  4. Iron, anemia and hepcidin in malaria

    PubMed Central

    Spottiswoode, Natasha; Duffy, Patrick E.; Drakesmith, Hal

    2014-01-01

    Malaria and iron have a complex but important relationship. Plasmodium proliferation requires iron, both during the clinically silent liver stage of growth and in the disease-associated phase of erythrocyte infection. Precisely how the protozoan acquires its iron from its mammalian host remains unclear, but iron chelators can inhibit pathogen growth in vitro and in animal models. In humans, iron deficiency appears to protect against severe malaria, while iron supplementation increases risks of infection and disease. Malaria itself causes profound disturbances in physiological iron distribution and utilization, through mechanisms that include hemolysis, release of heme, dyserythropoiesis, anemia, deposition of iron in macrophages, and inhibition of dietary iron absorption. These effects have significant consequences. Malarial anemia is a major global health problem, especially in children, that remains incompletely understood and is not straightforward to treat. Furthermore, the changes in iron metabolism during a malaria infection may modulate susceptibility to co-infections. The release of heme and accumulation of iron in granulocytes may explain increased vulnerability to non-typhoidal Salmonella during malaria. The redistribution of iron away from hepatocytes and into macrophages may confer host resistance to superinfection, whereby blood-stage parasitemia prevents the development of a second liver-stage Plasmodium infection in the same organism. Key to understanding the pathophysiology of iron metabolism in malaria is the activity of the iron regulatory hormone hepcidin. Hepcidin is upregulated during blood-stage parasitemia and likely mediates much of the iron redistribution that accompanies disease. Understanding the regulation and role of hepcidin may offer new opportunities to combat malaria and formulate better approaches to treat anemia in the developing world. PMID:24910614

  5. Encapsulation of iron in liposomes significantly improved the efficiency of iron supplementation in strenuously exercised rats.

    PubMed

    Xu, Zi; Liu, Shangyuan; Wang, Huijie; Gao, Guofen; Yu, Peng; Chang, Yanzhong

    2014-12-01

    To investigate the effect of iron liposome supplementation, a rat model of exercise-associated anemia was established by subjecting the animals to high-intensity running exercises for 4 weeks. Rats with confirmed anemia were strenuously exercised for another 2 weeks while receiving iron supplements by intragastric administration of ferric ammonium citrate (FAC) liposomes or heme iron liposomes. Control groups were administered equivalent amounts of FAC, heme iron, or blank liposomes. Subsequently, complete blood count (CBC), serum iron, and liver iron levels were tested to determine the efficiency of iron liposomes in relieving anemia. Superoxide dismutase (SOD) and malonyldialdehyde (MDA) were also detected to determine potential side effects of iron supplementation. The CBC, as well as serum iron and liver iron contents, significantly increased and reached much higher levels in anemic rats treated with iron liposomes, compared with those of control groups. The increase of SOD and decrease of MDA levels were also observed after supplementation with iron liposomes. These results demonstrate that iron liposomes can efficiently relieve the iron deficiency in strenuously exercised rats and may potentially be used as a supplement for the treatment of exercise-associated iron deficiency anemia with minimal side effects. PMID:25296704

  6. Hadronic Shower Development in Tile Iron-Scintillator Calorimetry

    E-print Network

    Yuri A. Kulchitsky

    1999-10-07

    The lateral and longitudinal profiles of hadronic showers detected by a prototype of the ATLAS Iron-Scintillator Tile Hadron Calorimeter have been investigated. This calorimeter uses a unique longitudinal configuration of scintillator tiles. Using a fine-grained pion beam scan at 100 GeV, a detailed picture of transverse shower behavior is obtained. The underlying radial energy densities for four depth segments and for the entire calorimeter have been reconstructed. A three-dimensional hadronic shower parametrization has been developed. The results presented here are useful for understanding the performance of iron-scintillator calorimeters, for developing fast simulations of hadronic showers, for many calorimetry problems requiring the integration of a shower energy deposition in a volume and for future calorimeter design.

  7. Hadronic Shower Development in Iron-Scintillator Tile Calorimetry

    E-print Network

    Tilecal Atlas Collaboration

    1999-04-29

    The lateral and longitudinal profiles of hadronic showers detected by a prototype of the ATLAS Iron-Scintillator Tile Hadron Calorimeter have been investigated. This calorimeter uses a unique longitudinal configuration of scintillator tiles. Using a fine-grained pion beam scan at 100 GeV, a detailed picture of transverse shower behavior is obtained. The underlying radial energy densities for four depth segments and for the entire calorimeter have been reconstructed. A three-dimensional hadronic shower parametrization has been developed. The results presented here are useful for understanding the performance of iron-scintillator calorimeters, for developing fast simulations of hadronic showers, for many calorimetry problems requiring the integration of a shower energy deposition in a volume and for future calorimeter design.

  8. Iron Acquisition and Expression of Iron Regulatory Proteins in the Developing Brain: Manipulation by Ethanol Exposure, Iron Deprivation and Cellular Dysfunction

    Microsoft Academic Search

    James R. Connor

    1994-01-01

    The World Health Organization considers iron deficiency the number one nutritional disorder in the world. In this review, the normal pattern for iron accumulation and expression of iron regulatory proteins (transferrin and its receptor, and ferritin) in brain during development are examined biochemically and at the cellular and molecular levels. Iron and the iron-regulatory proteins are at their highest postnatal

  9. On risks and benefits of iron supplementation recommendations for iron intake revisited.

    PubMed

    Schümann, Klaus; Ettle, Thomas; Szegner, Bernadett; Elsenhans, Bernd; Solomons, Noel W

    2007-01-01

    Iron is an essential trace element with a high prevalence of deficiency in infants and in women of reproductive age from developing countries. Iron deficiency is frequently associated with anaemia and, thus, with reduced working capacity and impaired intellectual development. Moreover, the risk for premature delivery, stillbirth and impaired host-defence is increased in iron deficiency. Iron-absorption and -distribution are homeostatically regulated to reduce the risk for deficiency and overload. These mechanisms interact, in part, with the mechanisms of oxidative stress and inflammation and with iron availability to pathogens. In the plasma, fractions of iron may not be bound to transferrin and are hypothesised to participate in atherogenesis. Repleted iron stores and preceding high iron intakes reduce intestinal iron absorption which, however, offers no reliable protection against oral iron overload. Recommendations for dietary iron intake at different life stages are given by the US Food and Nutrition Board (FNB), by FAO/WHO and by the EU Scientific Committee, among others. They are based, on estimates for iron-losses, iron-bioavailability from the diet, and iron-requirements for metabolism and growth. Differences in choice and interpretation of these estimates lead to different recommendations by the different panels which are discussed in detail. Assessment of iron-related risks is based on reports of adverse health effects which were used in the attempts to derive an upper safe level for dietary iron intake. Iron-related harm can be due to direct intestinal damage, to oxidative stress, or to stimulated growth of pathogens. Unfortunately, it is problematic to derive a reproducible cause-effect and dose-response relationship for adverse health effects that suggest a relationship to iron-intake, be they based on mechanistic or epidemiological observations. Corresponding data and interpretations are discussed for the intestinal lumen, the vascular system and for the intracellular and interstitial space, considering interference of the mechanisms of iron homoeostasis as a likely explanation for differences in epidemiological observations. PMID:17697954

  10. Cellular Iron Distribution in Bacillus anthracis

    PubMed Central

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

    2012-01-01

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

  11. Falling clothes irons rarely cause burns.

    PubMed

    Allasio, David; Shanti, Christina

    2014-01-01

    Children's Hospital of Michigan's Burn Center treats approximately three pediatric contact burns annually related to clothes irons, which involve the face, torso, and extremities. These burns leave well-demarcated burn patterns, including the steam holes from the heat plate of the iron. The average age of these children is 15 months. The history given by the parent is that the child pulled the cord of an iron that was on an ironing board or high shelf. It seemed unlikely to the investigators that a falling iron would produce such demarcated burns. A free-standing shelf unit was built with shelf heights of 36, 60, and 72 inches (the height of an ironing board and shelves at home). Three irons of different weights were put in three different positions on each shelf, with the cord dangling. A doll the approximate size of a 15-month old was positioned in front of the shelf. The dangling cord was pulled, and the falling iron was videotaped. The video was edited in freeze frame at the point at which the iron hit the doll. Two hundred seventy falls were recorded. The flat heat plate of the iron never hit the doll. The linear edge of the heat plate hit the doll on only seven falls. This study demonstrates that it is very unlikely for the flat heat plate of a falling iron to contact a toddler-sized doll. Children who allegedly sustain demarcated burns in this manner need to be investigated for nonaccidental injury. PMID:24476991

  12. Chelators affecting iron absorption in mice.

    PubMed

    Kontoghiorghes, G J

    1990-12-01

    The effect of natural and synthetic chelators on iron (59Fe) absorption in mice has been studied in three different experiments using single or repeated intragastric administrations of chelator iron (59Fe) complexes of different chelator doses. The amount of 59Fe in whole animals, their excretions and also distribution of 59Fe in blood, liver, spleen and heart was measured at one, three and eight weeks following the 59Fe-chelator administrations and compared to controls which received the same amount of iron (59Fe) but no chelator. 2-Hydroxy-4-methoxypyridine-1-oxide and maltol, which form lipophilic iron complexes, were found to cause an increase of 59Fe absorption while other chelators caused a decrease either by precipitating iron eg. 2-hydroxypyridine-1-oxide or by forming non absorbable soluble iron complexes eg. desferrioxamine, mimosine, EDTA. 1,2-Dimethyl-3-hydroxypyrid-4-one caused a decrease in iron absorption at a high dose (10 mg) by comparison to the control group but it did not significantly alter iron absorption at a lower dose (2 mg). It is suggested that natural and synthetic iron chelating compounds influence the absorption of iron and some may have a use in the treatment of diseases associated with gastro-intestinal iron absorption imbalance. PMID:2095129

  13. RADIOACTIVE IRON AND ITS METABOLISM IN ANEMIA

    PubMed Central

    Hahn, P. F.; Bale, W. F.; Lawrence, E. O.; Whipple, G. H.

    1939-01-01

    Artificially produced radioactive iron is an extremely sensitive agent for use in following iron in the course of its changes in body metabolism, lending itself to studies of absorption, transport, exchange, mobilization, and excretion. The need of the body for iron in some manner determines the absorption of this element. In the normal dog when there is no need for the element, it is absorbed in negligible amounts. In the anemic animal iron is quite promptly assimilated. The plasma is clearly the means of transport of iron from the gastrointestinal tract to its point of mobilization for fabrication into hemoglobin. The speed of absorption and transfer of iron to the red cell is spectacular. The importance of the liver and bone marrow in iron metabolism is confirmed. PMID:19870874

  14. Corrosion of Ultrathin Iron Layers and Titanium Nitride Coated Iron

    Microsoft Academic Search

    J. F. Marco; M. Gracia; J. R. Gancedo; A. Agudelo; W. Exel; W. Meisel; D. Hanzel

    2001-01-01

    In this paper results are presented on the corrosion resistance against SO2-polluted atmospheres of ultrathin Fe layers (2\\/Si wafers by two methods: vacuum evaporation and Langmuir–Blodgett (LB) technique. It is shown that the corrosion resistance\\u000a of the evaporated films is similar to that shown by massive iron while the corrosion resistance of the LB films is remarkably\\u000a higher. We also

  15. Ironing out the statistical wrinkles in "ten ironic rules".

    PubMed

    Lindquist, Martin A; Caffo, Brian; Crainiceanu, Ciprian

    2013-11-01

    The article "Ten ironic rules for non-statistical reviewers" (Friston, 2012) shares some commonly heard frustrations about the peer-review process that all researchers can identify with. Though we found the article amusing, we have some concerns about its description of a number of statistical issues. In this commentary we address these issues, as well as the premise of the article. PMID:23587691

  16. Iron Cycling at Loihi Seamount

    NASA Astrophysics Data System (ADS)

    Emerson, D.

    2007-12-01

    Loi"hi is an active submarine volcano located close to the island of Hawai"i at a depth around 1100 m. The summit is host to a variety of focused and diffuse flow hydrothermal vent sites, which have in common a chemistry that is dominated by the presence of Fe(II) often in concentrations of 10's to 100's of ?M at circumneutral pH. An outcome of these conditions is the deposition of substantial quantities of rust-colored microbial mats that are dominated by Fe-oxidizing bacteria (FeOB). These mat communities were first sampled in the late 1980s, and have subsequently been the subject of continued investigation, to the extent that Loih'i is now a model system for understanding deep-sea microbial communites that are primarily driven by iron-based lithotrophic metabolism. While the role of FeOB is becoming well-established, the short-term fate of the iron oxyhydroxides that are produced is less well understood, and specifically that role that Fe-reducing bacteria may have in re-cycling Fe(III) to Fe(II). A recent cruise to Loihi in 2006 found that one vent site, which has been slowly decreasing in activity, was essentially "dead", i.e. there was no sign of fluid flow or temperature anomaly. Yet, iron mats several cm thick persisted and chemical analysis suggested O2 penetrated the mat and that no Fe(II) was present, i.e. there no sign of active Fe-reduction. This raises the question of how active is the iron cycle in Loih'i iron mats? Experiments to measure Fe- reduction potential in Lohi"i mats do show activity and it is possible to enrich Fe-reducing bacteria. We have recently isolated a novel Geothermobacter sp. HR-1 from a Loih'i mat, that is an Fe-reducer and grows at mesophilic temperatures. This work will report on continued investigations into the iron cycle at Loih'i to further constrain the chemical conditions, further elucidate the potential for Fe-reduction in natural mat samples, and present the outcome of growing native isolates of Fe- oxidizers and reducers from Loih'i in co-culture.

  17. Iron nutrition and premenopausal women: effects of poor iron status on physical and neuropsychological performance.

    PubMed

    McClung, James P; Murray-Kolb, Laura E

    2013-01-01

    Iron is a nutritionally essential trace element that functions through incorporation into proteins and enzymes, many of which contribute to physical and neuropsychological performance. Poor iron status, including iron deficiency (ID; diminished iron stores) and iron deficiency anemia (IDA; poor iron stores and diminished hemoglobin), affects billions of people worldwide. This review focuses on physical and neuropsychological outcomes associated with ID and IDA in premenopausal women, as the prevalence of ID and IDA is often greater in premenopausal women than other population demographics. Recent studies addressing the physiological effects of poor iron status on physical performance, including work productivity, voluntary activity, and athletic performance, are addressed. Similarly, the effects of iron status on neurological performance, including cognition, affect, and behavior, are summarized. Nutritional countermeasures for the prevention of poor iron status and the restoration of decrements in performance outcomes are described. PMID:23642204

  18. Olfactory ferric and ferrous iron absorption in iron-deficient rats

    PubMed Central

    Ruvin Kumara, V. M.

    2012-01-01

    The absorption of metals from the nasal cavity to the blood and the brain initiates an important route of occupational exposures leading to health risks. Divalent metal transporter-1 (DMT1) plays a significant role in the absorption of intranasally instilled manganese, but whether iron uptake would be mediated by the same pathway is unknown. In iron-deficient rats, blood 59Fe levels after intranasal administration of the radioisotope in the ferrous form were significantly higher than those observed for iron-sufficient control rats. Similar results were obtained when ferric iron was instilled intranasally, and blood levels of 59Fe were even greater in the iron-deficient rats compared with the amount of ferrous iron absorbed. Experiments with Belgrade (b/b) rats showed that DMT1 deficiency limited ferric iron uptake from the nasal cavity to the blood compared with +/b controls matched for iron deficiency. These results indicate that olfactory uptake of ferric iron by iron-deficient rats involves DMT1. Western blot experiments confirmed that DMT1 levels are significantly higher in iron-deficient rats compared with iron-sufficient controls in olfactory tissue. Thus the molecular mechanism of olfactory iron absorption is regulated by body iron status and involves DMT1. PMID:22492739

  19. Iron stable isotopes track pelagic iron cycling during a subtropical phytoplankton bloom

    PubMed Central

    Ellwood, Michael J.; Hutchins, David A.; Lohan, Maeve C.; Milne, Angela; Nasemann, Philipp; Nodder, Scott D.; Sander, Sylvia G.; Wilhelm, Steven W.; Boyd, Philip W.

    2015-01-01

    The supply and bioavailability of dissolved iron sets the magnitude of surface productivity for ?40% of the global ocean. The redox state, organic complexation, and phase (dissolved versus particulate) of iron are key determinants of iron bioavailability in the marine realm, although the mechanisms facilitating exchange between iron species (inorganic and organic) and phases are poorly constrained. Here we use the isotope fingerprint of dissolved and particulate iron to reveal distinct isotopic signatures for biological uptake of iron during a GEOTRACES process study focused on a temperate spring phytoplankton bloom in subtropical waters. At the onset of the bloom, dissolved iron within the mixed layer was isotopically light relative to particulate iron. The isotopically light dissolved iron pool likely results from the reduction of particulate iron via photochemical and (to a lesser extent) biologically mediated reduction processes. As the bloom develops, dissolved iron within the surface mixed layer becomes isotopically heavy, reflecting the dominance of biological processing of iron as it is removed from solution, while scavenging appears to play a minor role. As stable isotopes have shown for major elements like nitrogen, iron isotopes offer a new window into our understanding of the biogeochemical cycling of iron, thereby allowing us to disentangle a suite of concurrent biotic and abiotic transformations of this key biolimiting element. PMID:25535372

  20. Influence of Inflammatory Disorders and Infection on Iron Absorption and Efficacy of Iron- Fortified Foods

    PubMed Central

    Hurrell, Richard F.

    2014-01-01

    The provision of iron- fortified foods is a common strategy to prevent iron deficiency; however, ensuring adequate iron absorption is a challenge. Iron bioavailability depends on the choice of iron compound, the presence enhancers and inhibitors of absorption in the food matrix, and the physiological state of the consumer, including iron status, other nutritional deficiencies and inflammatory disorders. Inflammation associated with infections and inflammatory disorders would be expected to decrease iron absorption and reduce the efficacy of iron- fortified foods. The decreased absorption is due to an increase in circulating hepcidin in response to inflammatory cytokines. Hepcidin degrades ferroportin and blocks the passage of iron from the intestinal cell to the plasma. This is the innate immune response to infections and aims to restrict pathogen growth by restricting iron supply. Stable isotope studies have reported women and children with chronic malaria parasitemia or febrile malaria to have increased inflammatory cytokines, increased hepcidin and much decreased iron absorption. No studies have specifically investigated the efficacy of iron- fortified foods in the absence and presence of infections. In contrast, inflammation and increased hepcidin associated with adiposity in overweight have been linked to both lower iron absorption and the decreased efficacy of iron- fortified foods. PMID:25762975

  1. Iron stable isotopes track pelagic iron cycling during a subtropical phytoplankton bloom.

    PubMed

    Ellwood, Michael J; Hutchins, David A; Lohan, Maeve C; Milne, Angela; Nasemann, Philipp; Nodder, Scott D; Sander, Sylvia G; Strzepek, Robert; Wilhelm, Steven W; Boyd, Philip W

    2015-01-01

    The supply and bioavailability of dissolved iron sets the magnitude of surface productivity for ? 40% of the global ocean. The redox state, organic complexation, and phase (dissolved versus particulate) of iron are key determinants of iron bioavailability in the marine realm, although the mechanisms facilitating exchange between iron species (inorganic and organic) and phases are poorly constrained. Here we use the isotope fingerprint of dissolved and particulate iron to reveal distinct isotopic signatures for biological uptake of iron during a GEOTRACES process study focused on a temperate spring phytoplankton bloom in subtropical waters. At the onset of the bloom, dissolved iron within the mixed layer was isotopically light relative to particulate iron. The isotopically light dissolved iron pool likely results from the reduction of particulate iron via photochemical and (to a lesser extent) biologically mediated reduction processes. As the bloom develops, dissolved iron within the surface mixed layer becomes isotopically heavy, reflecting the dominance of biological processing of iron as it is removed from solution, while scavenging appears to play a minor role. As stable isotopes have shown for major elements like nitrogen, iron isotopes offer a new window into our understanding of the biogeochemical cycling of iron, thereby allowing us to disentangle a suite of concurrent biotic and abiotic transformations of this key biolimiting element. PMID:25535372

  2. High fat diet subverts hepatocellular iron uptake determining dysmetabolic iron overload.

    PubMed

    Dongiovanni, Paola; Lanti, Claudia; Gatti, Stefano; Rametta, Raffaela; Recalcati, Stefania; Maggioni, Marco; Fracanzani, Anna Ludovica; Riso, Patrizia; Cairo, Gaetano; Fargion, Silvia; Valenti, Luca

    2015-01-01

    Increased serum ferritin associated with mild hepatic iron accumulation, despite preserved upregulation of the iron hormone hepcidin, is frequently observed in patients with dysmetabolic overload syndrome (DIOS). Genetic factors and Western diet represent predisposing conditions, but the mechanisms favoring iron accumulation in DIOS are still unclear. Aims of this study were to assess the effect a high-fat diet (HFD) on hepatic iron metabolism in an experimental model in rats, to further characterize the effect of free fatty acids on iron metabolism in HepG2 hepatocytes in vitro, and to assess the translational relevance in patients with fatty liver with and without iron accumulation. Despite decreased uptake of dietary iron, rats fed HFD accumulated more hepatic iron than those fed regular diet, which was associated with steatosis development. Hepatic iron accumulation was paralleled by induction of ferritin, in the presence of preserved upregulation of hepcidin, recapitulating the features of DIOS. HFD was associated with increased expression of the major iron uptake protein Transferrin receptor-1 (TfR-1), consistently with upregulation of the intracellular iron sensor Iron regulated protein-1 (IRP1). Supplementation with fatty acids induced TfR-1 and IRP1 in HepG2 hepatocytes, favoring intracellular iron accumulation following exposure to iron salts. IRP1 silencing completely abrogated TfR-1 induction and the facilitation of intracellular iron accumulation induced by fatty acids. Hepatic TfR-1 mRNA levels were upregulated in patients with fatty liver and DIOS, whereas they were not associated with liver fat nor with inflammation. In conclusion, increased exposure to fatty acids subverts hepatic iron metabolism, favoring the induction of an iron uptake program despite hepatocellular iron accumulation. PMID:25647178

  3. Effects of iron-reducing bacteria on carbon steel corrosion induced by thermophilic sulfate-reducing consortia.

    PubMed

    Valencia-Cantero, Eduardo; Peña-Cabriales, Juan José

    2014-02-28

    Four thermophilic bacterial species, including the iron-reducing bacterium Geobacillus sp. G2 and the sulfate-reducing bacterium Desulfotomaculum sp. SRB-M, were employed to integrate a bacterial consortium. A second consortium was integrated with the same bacteria, except for Geobacillus sp. G2. Carbon steel coupons were subjected to batch cultures of both consortia. The corrosion induced by the complete consortium was 10 times higher than that induced by the second consortium, and the ferrous ion concentration was consistently higher in iron-reducing consortia. Scanning electronic microscopy analysis of the carbon steel surface showed mineral films colonized by bacteria. The complete consortium caused profuse fracturing of the mineral film, whereas the non-iron-reducing consortium did not generate fractures. These data show that the iron-reducing activity of Geobacillus sp. G2 promotes fracturing of mineral films, thereby increasing steel corrosion. PMID:24225375

  4. Numerical methods for estimating iron requirements from population data

    Microsoft Academic Search

    Katsuhiko Yokoi

    2003-01-01

    The estimation of iron requirements is crucial for nutrition and food policy. The traditional methods for estimating iron\\u000a requirements are balance methods based on iron intakes and excretions and factorial methods based on estimated iron absorption\\u000a rates and estimated iron losses from body compartments. As an alternative, numerical methods for estimating iron requirements\\u000a from population data of iron status were

  5. Iron storage disease in tapirs.

    PubMed

    Bonar, Christopher J; Trupkiewicz, John G; Toddes, Barbara; Lewandowski, Albert H

    2006-03-01

    Recent studies of serum iron and iron binding capacity have indicated that tapirs could be at risk of developing hemochromatosis. However, in recent surveys of pathologic findings in tapirs, hemochromatosis was not reported as a cause of death. This study reviews necropsy reports from three species of tapir (Baird's tapir [Tapirus bairdii], Malayan tapir [Tapirus indicus], and Brazilian tapir [Tapirus terrestris]) at the Philadelphia Zoological Garden between 1902 and 1994. Twelve cases of hemosiderosis, including fatal hemochromatosis in two Baird's tapirs, were found among 19 cases examined histologically. Hemochromatosis has previously been reported in the horse, rhinoceros, and in one Brazilian tapir. Dietary factors were investigated but could not be confirmed to have contributed to the incidence of hemosiderosis and hemochromatosis in the three species of tapir in the Philadelphia Zoological Garden collection. PMID:17312812

  6. Thermopower of thin iron films

    NASA Astrophysics Data System (ADS)

    Schepis, Randy; Schröder, Klaus

    1992-02-01

    Thin iron films were prepared by evaporation in a high vacuum system (pressure in the 10 -5 MPa range). The thermopower was measured in situ near room temperature as a function of film thickness. Iron films with rather high resistivity values showed a strong thickness effect of the Seeback coefficient, S, with the difference between S (bulk) and S (film) reaching values of up to (19±3) ?V/K for a sample 5 nm thick. The difference between S (bulk) and S (film) decreased with increasing d values. However, a sample with a resistance value of 50 ?? cm at d = 5 n had an S value which differed by less than 3 ?V/K from S (bulk).

  7. Iron-tolerant Cyanobacteria as a Tool to Study Terrestrial and Extraterrestrial Iron Deposition

    NASA Technical Reports Server (NTRS)

    Brown, I. I.; Mummey, D.; Cooksey, K. E.; McKay, D. S.

    2005-01-01

    We are investigating biological mechanisms of terrestrial iron deposition as analogs for Martian hematite recently confirmed by. Possible terrestrial analogs include iron oxide hydrothermal deposits, rock varnish, iron-rich laterites, ferricrete soils, moki balls, and banded iron formations (BIFs). With the discovery of recent volcanic activity in the summit craters of five Martian volcanoes, renewed interest in the iron dynamics of terrestrial hydrothermal environments and associated microorganisms is warranted. In this study we describe a new genus and species of CB exhibiting elevated dissolved iron tolerance and the ability to precipitate hematite on the surface of their exopolymeric sheathes.

  8. Reactive iron in marine sediments

    Microsoft Academic Search

    Donald E. Canfield

    1989-01-01

    A combined field\\/laboratory study has been undertaken to explore the mineralogy, concentrations and reactivity (towards sulfide) of iron in marine sediments. Also considered is the importance of bacterial Fe liberation in regulating pore-water chemistry. Two contrasting marine environments are included; one is the relatively Fe-poor FOAM site and the other is the Fe-rich sediment of the subaqueous Mississippi Delta. Results

  9. Interaction of iron and folate during reproduction.

    PubMed

    O'Connor, D L

    1991-01-01

    Biochemical evidence collected from both clinical and non-institutionalized populations indicate that iron and folate deficiencies frequently occur simultaneously. Supplementation trials of iron-deficient patients with either iron or iron and folate has helped to illustrate that a complex interrelationship exists between these two nutrients. Controlled animal trials in which dietary iron and folate content has been systematically manipulated reveal that iron deficiency can cause altered folate utilization. The impact of iron deficiency on folate metabolism is most dramatic during the reproductive and neonatal stages of the life cycle. Rat pups and piglets nursed by dams fed iron-depleted diets exhibit signs of altered folate utilization. Depressed milk folate secretion is an early manifestation of iron deficiency in the rat dam and is a prime factor responsible for folate depletion in their nursing pups. Impaired milk folate secretion during iron deficiency is not due to a decrease in the amount of folate supplied to the mammary gland; rather, the defect causing this reduction is specific to the mammary gland. PMID:1784737

  10. What is new in iron overload?

    PubMed Central

    2007-01-01

    Children with severe chronic hemolytic anemia or congenital erythroblastopenia are transfusion dependent. Long-term transfusion therapy prolongs life but results in a toxic accumulation of iron in the organs. The human body cannot actively eliminate excess iron. Therefore, the use of a chelating agent is required to promote excretion of iron. So far, iron chelation has been done by subcutaneous infusion of deferoxamine given over 10 h, 5–6 days per week. Compliance is poor and chelation often insufficient. Ferritin measurements and sometimes liver biopsies are used to evaluate the iron burden in the body. At the present time, new iron chelators that can be given orally are available. Furthermore, magnetic resonance imaging (MRI) assessment of tissue iron is a noninvasive and highly reproducible method, which is able to quantitate organ iron burden. In conclusion, iron overload can be measured more accurately with noninvasive methods such as MRI. Deferasirox is a once-daily oral therapy for treating transfusional iron overload, which improves patient compliance and quality of life. PMID:17899187

  11. Leaching of aluminum and iron from boiler slag generated from a typical Chinese Steel Plant

    Microsoft Academic Search

    Jinping Li; Jinhua Gan; Xianwang Li

    2009-01-01

    This paper presents a new way of recycling aluminum and iron in boiler slag derived from coal combustion plants, which integrates efficient extraction and reuse of the leached pellets together. The boiler slag was pelletised together with washed coal and lime prior to sintering and then was sintered at 800–1200°C for different periods to produce sintered pellets for the leaching

  12. POLLUTION EFFECTS OF ABNORMAL OPERATIONS IN IRON AND STEEL MAKING. VOLUME II. SINTERING, MANUAL OF PRACTICE

    EPA Science Inventory

    The report is one in a six-volume series considering abnormal operating conditions (AOCs) in the primary section (sintering, blast furnace ironmaking, open hearth, electric furnace, and basic oxygen steelmaking) of an integrated iron and steel plant. Pollution standards, generall...

  13. EMISSION FACTORS FOR IRON AND STEEL SOURCES: CRITERIA AND TOXIC POLLUTANTS

    EPA Science Inventory

    The report provides a comprehensive set of emission factors for sources of both criteria and toxic air pollutants in integrated iron and steel plants and specialty electric arc shops (minimills). Emission factors are identified for process sources, and process and open source fug...

  14. EMISSION FACTORS FOR IRON AND STEEL SOURCES -- CRITERIA AND TOXIC POLLUTANTS

    EPA Science Inventory

    The report provides a comprehensive set of emission factors for sources of both criteria and toxic air pollutants in integrated iron and steel plants and specialty electric arc shops (minimills). Emission factors are identified for process sources, and process and open source fug...

  15. Saugus Iron Works: Life and Work at an Early American Industrial Site. Teaching with Historic Places.

    ERIC Educational Resources Information Center

    Whitman, Maryann

    In 1948 archeologists verified that a now overgrown and urbanized landscape along the Saugus River (Massachusetts) was the site of the Saugus Iron Works from 1646 until 1648. That discovery led to a careful, though partly conjectural, reconstruction of the first successful integrated ironmaking plant in the colonial America. The early Puritan…

  16. SURVEY OF FOULING, FOAM, CORROSION, AND SCALING CONTROL IN IRON AND STEEL INDUSTRY RECYCLE SYSTEMS

    EPA Science Inventory

    The report gives results of a review of the state-of-the-art for fouling, foaming, corrosion, and scaling control in the treatment and recycle of process waters of integrated iron and steel mills. Areas examined were: (1) the character of the wastewaters generated in the differen...

  17. Iron Incorporation and Post-Malaria Anaemia

    PubMed Central

    Doherty, Conor P.; Cox, Sharon E.; Fulford, Antony J.; Austin, Steven; Hilmers, David C.; Abrams, Steven A.; Prentice, Andrew M.

    2008-01-01

    Background Iron supplementation is employed to treat post-malarial anaemia in environments where iron deficiency is common. Malaria induces an intense inflammatory reaction that stalls reticulo-endothelial macrophagal iron recycling from haemolysed red blood cells and inhibits oral iron absorption, but the magnitude and duration of these effects are unclear. Methodology/Principal Findings We examined the red blood cell incorporation of oral administered stable isotopes of iron and compared incorporation between age matched 18 to 36 months old children with either anaemia post-malaria (n?=?37) or presumed iron deficiency anaemia alone (n?=?36). All children were supplemented for 30 days with 2 mg/kg elemental iron as liquid iron sulphate and administered 57Fe and 58Fe on days 1 and 15 of supplementation respectively. 57Fe and58Fe incorporation were significantly reduced (8% vs. 28%: p<0.001 and 14% vs. 26%: p?=?0.045) in the malaria vs. non-malaria groups. There was a significantly greater haemoglobin response in the malaria group at both day 15 (p?=?0.001) and 30 (p<0.000) with a regression analysis estimated greater change in haemoglobin of 7.2 g/l (s.e. 2.0) and 10.1 g/l (s.e. 2.5) respectively. Conclusion/Significance Post-malaria anaemia is associated with a better haemoglobin recovery despite a significant depressant effect on oral iron incorporation which may indicate that early erythropoetic iron need is met by iron recycling rather than oral iron. Supplemental iron administration is of questionable utility within 2 weeks of clinical malaria in children with mild or moderate anaemia. PMID:18461143

  18. Extending hydraulic lifetime of iron walls

    SciTech Connect

    Mackenzie, P.D. [General Electric Corp. Research and Development Center, Schenectady, NY (United States); Sivavec, T.M.; Horney, D.P.

    1997-12-31

    Iron walls for control of groundwaters contaminated with chlorinated solvents and reducible metals are becoming much more widely used and field studies of this technology have proven successful to date. However, there is still much uncertainty in predicting long-term performance. This work focuses on two factors affecting the lifetime of the iron media: plugging at the treatment zone entrance and precipitation in the bulk iron media. Plugging at the system entrance is due principally to dissolved oxygen in the incoming water and is an issue in aerobic aquifers or in ex-situ canister tests. In an in-situ treatment system, plugging would result in a dramatic reduction in flow through the iron zone. Designs to minimize plugging in field applications include use of larger iron particles and admixing sand of comparable size with the iron particles. Mineral precipitation in the bulk iron media can lead to porosity losses in the media, again reducing flow through the treatment zone. Decreases in reactivity of the iron media may also occur. The nature of the mineral precipitation and the factors that affect extent of mineral precipitation are examined by a variety of tools, including tracer tests, aqueous inorganic profiles, and surface analysis techniques. At short treatment times, measured porosity losses are due mainly to entrapment of a film of H{sub 2} gas on the iron surfaces and also to Fe(OH){sub 2} precipitation. Over longer treatment times precipitation of Fe(OH){sub 2} and FeCO{sub 3} in low carbonate waters and of Fe(OH){sub 2}, FeCO{sub 3} and CaCO{sub 3} in higher carbonate waters will begin to dominate porosity losses. Preliminary results of an on-going study to control pH in an iron zone by admixing iron sulfide with iron show no difference in extent of carbonate precipitation versus a 100% iron system, suggesting that these systems are supersaturated with respect to carbonate precipitation.

  19. Green tea catechins as brain-permeable, non toxic iron chelators to “iron out iron” from the brain

    Microsoft Academic Search

    S. Mandel; O. Weinreb; L. Reznichenko; L. Kalfon; T. Amit

    Evidence to link abnormal metal (iron, copper and zinc) metabolism and handling with Parkinson’s and Alzheimer’s diseases\\u000a pathology has frequently been reported. The capacity of free iron to enhance and promote the generation of toxic reactive\\u000a oxygen radicals has been discussed numerous times. Metal chelation has the potential to prevent iron-induced oxidative stress\\u000a and aggregation of alpha-synuclein and beta-amyloid peptides.

  20. Iron and iron chelators: a review on potential effects on skin aging.

    PubMed

    Pouillot, Anne; Polla, Ada; Polla, Barbara S

    2013-12-01

    Similar to oxygen, iron is essential for aerobic life and energy production. Akin to oxygen, iron can be toxic and accelerate the aging process. Indeed, via the Fenton and Haber Weiss reactions, iron potentiates the generation of highly reactive oxygen free radicals such as hydroxyl radical, thus stimulating oxidative damage. The possibility that women's longer life span relates to a lower iron status due to iron loss during reproductive life has been considered as a valid hypothesis, while hemochromatosis has been proposed as a model of iron overload to examine the effects of iron on the aging process. Iron plays an aggravating role in many diseases in which iron deprivation has been shown to be beneficial including ischaemia-reperfusion injury, neurological disorders and muscle diseases such as Duchenne's muscular dystrophy. In the skin, excess iron combined with UV radiation exerts pro-oxidant effects while scavenging of free iron prevents or inhibits the toxic effects of UV radiation on both nude mice and human skin. In this review, we propose that iron chelators and/or iron deprivation might play a significant role in the prevention of aging- associated diseases and conditions, in particular in the skin, and increase quality of life. Controlled iron deprivation might be achieved by regular blood donation in which case the quality of life of both the donor and the recipient is improved. Increasing the frequency of blood donation may thus significantly contribute to both individual and social wellbeing. Furthermore, we propose the skin as an accessible model for the study of aging and the effects of iron / iron deprivation on the aging mechanisms. Finally, we suggest that the development of topical iron chelators might represent a novel and simple approach to prevent skin aging, when such prevention has proven an important factor in increasing an aging populations' quality of life. PMID:23866012

  1. Escherichia coli RIC Is Able to Donate Iron to Iron-Sulfur Clusters

    PubMed Central

    Nobre, Lígia S.; Garcia-Serres, Ricardo; Todorovic, Smilja; Hildebrandt, Peter; Teixeira, Miguel; Latour, Jean-Marc; Saraiva, Lígia M.

    2014-01-01

    Escherichia coli RIC (Repair of Iron Centers) is a diiron protein previously reported to be involved in the repair of iron-sulfur proteins damaged by oxidative or nitrosative stresses, and proposed to act as an iron donor. This possible role of RIC was now examined specifically by evaluating its ability to donate iron ions to apo-iron-sulfur proteins, determining the iron binding constants and assessing the lability of its iron ions. We show, by UV-visible, EPR and resonance Raman spectroscopies that RIC may participate in the synthesis of an iron-sulfur cluster in the apo-forms of the spinach ferredoxin and IscU when in the presence of the sulfide donating system IscS and L-cysteine. Iron binding assays allowed determining the as-isolated and fully reduced RIC dissociation constants for the ferric and ferrous iron of 10?27 M and 10?13 M, respectively. Mössbauer studies revealed that the RIC iron ions are labile, namely when the center is in the mixed-valence redox form as compared with the (?-oxo) diferric one. Altogether, these results suggest that RIC is capable of delivering iron for the formation of iron-sulfur clusters. PMID:24740378

  2. Malabsorption of iron as a cause of iron deficiency anemia in postmenopausal women

    PubMed Central

    Qamar, Khansa; Saboor, Muhammad; Qudsia, Fatima; Khosa, Shafi Muhammad; Moinuddin; Usman, Muhammad

    2015-01-01

    Objective: Malabsorption is one of the causes of iron deficiency anemia in postmenopausal women. The main objective of this study was to access the frequency of malabsorption in iron deficient anemic postmenopausal women. Methods: A total of 123 postmenopausal women were enrolled in the study. Of these 123 women, 50 were included as ‘control group’ and 73 patients with comparable severity of anemia were the ‘patient group’. Two tablets of ferrous sulfate (200 mg/tablet) along with one tablet of vitamin C (500 mg) were given to all participants. Serum iron levels were determined on samples collected from all participants before and after the administration of ferrous sulfate. Difference between before and after serum iron levels of normal and patients were compared. Results: No change in serum iron between sample one and sample two represented malabsorption. Out of 73, 5 postmenopausal anemic patients showed no change in their serum iron level after the administration of ferrous sulfate. This study shows that frequency of malabsorption of iron in postmenopausal women is 6.8%. Conclusion: Malabsorption should be considered as a prevalent cause of iron deficiency anemia in postmenopausal women. It should be properly diagnosed and iron response should be monitored properly in postmenopausal women with IDA after oral iron therapy. If a postmenopausal woman does not show any response to oral iron therapy, she should be evaluated for iron loss (blood loss and/or malabsorption). Intravenous route should be used for the administration of iron in these patients.

  3. Deferasirox and deferiprone remove cardiac iron in the iron-overloaded gerbil

    PubMed Central

    WOOD, JOHN C.; OTTO-DUESSEL, MAYA; GONZALEZ, IGNACIO; AGUILAR, MICHELLE I.; SHIMADA, HIRO; NICK, HANSPETER; NELSON, MARVIN; MOATS, REX

    2010-01-01

    Introduction Deferasirox effectively controls liver iron concentration; however, little is known regarding its ability to remove stored cardiac iron. Deferiprone seems to have increased cardiac efficacy compared with traditional deferoxamine therapy. Therefore, the relative efficacy of deferasirox and deferiprone were compared in removing cardiac iron from iron-loaded gerbils. Methods Twenty-nine 8- to 10-week-old female gerbils underwent 10 weekly iron dextran injections of 200 mg/kg/week. Prechelation iron levels were assessed in 5 animals, and the remainder received deferasirox 100 mg/kg/D po QD (n = 8), deferiprone 375 mg/kg/D po divided TID (n = 8), or sham chelation (n = 8), 5 days/week for 12 weeks. Results Deferasirox reduced cardiac iron content 20.5%. No changes occurred in cardiac weight, myocyte hypertrophy, fibrosis, or weight-to-dry weight ratio. Deferasirox treatment reduced liver iron content 51%. Deferiprone produced comparable reductions in cardiac iron content (18.6% reduction). Deferiprone-treated hearts had greater mass (16.5% increase) and increased myocyte hypertrophy. Deferiprone decreased liver iron content 24.9% but was associated with an increase in liver weight and water content. Conclusion Deferasirox and deferiprone were equally effective in removing stored cardiac iron in a gerbil animal model, but deferasirox removed more hepatic iron for a given cardiac iron burden. PMID:17145573

  4. Modelling Iron-Bentonite Interactions

    NASA Astrophysics Data System (ADS)

    Watson, C.; Savage, D.; Benbow, S.; Wilson, J.

    2009-04-01

    The presence of both iron canisters and bentonitic clay in some engineered barrier system (EBS) designs for the geological disposal of high-level radioactive wastes creates the potential for chemical interactions which may impact upon the long-term performance of the clay as a barrier to radionuclide migration. Flooding of potential radionuclide sorption sites on the clay by ferrous ions and conversion of clay to non-swelling sheet silicates (e.g. berthierine) are two possible outcomes deleterious to long-term performance. Laboratory experimental studies of the corrosion of iron in clay show that corrosion product layers are generally thin (< 1 µm) with magnetite, siderite, or ‘green rust' occurring depending upon temperature and ambient partial pressure of carbon dioxide. In theory, incorporation of iron into clay alteration products could act as a ‘pump' to accelerate corrosion. However, the results of laboratory experiments to characterise the products of iron-bentonite interaction are less than unequivocal. The type and amounts of solid products appear to be strong functions of time, temperature, water/clay ratio, and clay and pore fluid compositions. For example, the products of high temperature experiments (> 250 °C) are dominated by chlorite, whereas lower temperatures produce berthierine, odinite, cronstedtite, or Fe-rich smectite. Unfortunately, the inevitable short-term nature of laboratory experimental studies introduces issues of metastability and kinetics. The sequential formation in time of minerals in natural systems often produces the formation of phases not predicted by equilibrium thermodynamics. Evidence from analogous natural systems suggests that the sequence of alteration of clay by Fe-rich fluids will proceed via an Ostwald step sequence. The computer code, QPAC, has been modified to incorporate processes of nucleation, growth, precursor cannibalisation, and Ostwald ripening to address the issues of the slow growth of bentonite alteration products. This, together with inclusion of processes of iron corrosion and diffusion, has enabled investigation of a representative model of the alteration of bentonite in a typical EBS environment. Simulations with fixed mineral surface areas show that berthierine dominates the solid product assemblage, with siderite replacing it at simulation times greater than 10 000 years. Simulations with time-dependent mineral surface areas show a sequence of solid alteration products, described by: magnetite -> cronstedtite -> berthierine -> chlorite. Using plausible estimates of mineral-fluid interfacial free energies, chlorite growth is not achieved until 5 000 years of simulation time. The results of this modelling work suggest that greater emphasis should be placed upon methods to up-scale the results of laboratory experiments to timescales of relevance to performance assessment.

  5. SCADA control systems in integrated steel plants

    Microsoft Academic Search

    S. C. Bhatia

    1998-01-01

    Supervisory control and data acquisition (SCADA) systems have been in existence for a number of years now, They are employed in various applications which involve the simultaneous acquisition of large amounts of data, real-time processing, display and supervisory control. SCADA based controllers have been incorporated in integrated iron and steel plants in two packages-one to meet the requirements of SCADA

  6. The iron-regulated staphylococcal lipoproteins

    PubMed Central

    Sheldon, Jessica R.; Heinrichs, David E.

    2012-01-01

    Lipoproteins fulfill diverse roles in antibiotic resistance, adhesion, protein secretion, signaling and sensing, and many also serve as the substrate binding protein (SBP) partner to ABC transporters for the acquisition of a diverse array of nutrients including peptides, sugars, and scarcely abundant metals. In the staphylococci, the iron-regulated SBPs are significantly upregulated during iron starvation and function to sequester and deliver iron into the bacterial cell, enabling staphylococci to circumvent iron restriction imposed by the host environment. Accordingly, this subset of lipoproteins has been implicated in staphylococcal pathogenesis and virulence. Lipoproteins also activate the host innate immune response, triggered through Toll-like receptor-2 (TLR2) and, notably, the iron-regulated subset of lipoproteins are particularly immunogenic. In this review, we discuss the iron-regulated staphylococcal lipoproteins with regard to their biogenesis, substrate specificity, and impact on the host innate immune response. PMID:22919632

  7. Industry experience in promoting weekly iron-folic acid supplementation in the Philippines.

    PubMed

    Garcia, Josel; Datol-Barrett, Eva; Dizon, Maynilad

    2005-12-01

    After participating in a pilot project under a government-industry partnership to promote the adoption of weekly iron-folic acid supplementation among women of reproductive age in the Philippines in 1998, United Laboratories (UNILAB), the Philippines' largest private pharmaceutical company, decided in April 2002 to launch a weekly iron-folic acid supplement for pregnant and non-pregnant women under the brand name Femina. The business objective set for the Femina brand was to build the category of preventive iron-folic acid supplements in line with the Philippine Department of Health's advocacy on weekly supplementation as an alternate to daily dosing to reduce the prevalence of anemia in the country. The brand was supported with an integrated mix of traditional advertising media with complementary direct-to-consumer educational programs that aimed to create awareness of iron-deficiency anemia, its causes and effects, and the role of weekly intake of iron-folic acid in preventing the condition. Aggressive marketing support for 1 year was successful in creating awareness among the target women. Significant lessons derived from consumers identified opportunity areas that can be further addressed in developing advocacy programs on weekly iron supplementation implemented on a nationwide scale in the future. PMID:16466091

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

    PubMed

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

    2015-06-01

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

  9. 49 CFR 192.489 - Remedial measures: Cast iron and ductile iron pipelines.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...measures: Cast iron and ductile iron pipelines. 192.489 Section 192.489 Transportation...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL...

  10. 49 CFR 192.489 - Remedial measures: Cast iron and ductile iron pipelines.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...measures: Cast iron and ductile iron pipelines. 192.489 Section 192.489 Transportation...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL...

  11. 49 CFR 192.489 - Remedial measures: Cast iron and ductile iron pipelines.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...measures: Cast iron and ductile iron pipelines. 192.489 Section 192.489 Transportation...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL...

  12. 49 CFR 192.489 - Remedial measures: Cast iron and ductile iron pipelines.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...measures: Cast iron and ductile iron pipelines. 192.489 Section 192.489 Transportation...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL...

  13. 49 CFR 192.369 - Service lines: Connections to cast iron or ductile iron mains.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Service Regulators, and Service Lines § 192.369 Service lines: Connections to cast iron or...mains. (a) Each service line connected to a cast iron or...tapping the main, or by another method meeting the requirements...

  14. 49 CFR 192.369 - Service lines: Connections to cast iron or ductile iron mains.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Service Regulators, and Service Lines § 192.369 Service lines: Connections to cast iron or...mains. (a) Each service line connected to a cast iron or...tapping the main, or by another method meeting the requirements...

  15. 49 CFR 192.369 - Service lines: Connections to cast iron or ductile iron mains.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Service Regulators, and Service Lines § 192.369 Service lines: Connections to cast iron or...mains. (a) Each service line connected to a cast iron or...tapping the main, or by another method meeting the requirements...

  16. 49 CFR 192.369 - Service lines: Connections to cast iron or ductile iron mains.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Service Regulators, and Service Lines § 192.369 Service lines: Connections to cast iron or...mains. (a) Each service line connected to a cast iron or...tapping the main, or by another method meeting the requirements...

  17. Mechanism of iron uptake by the pathogenic yeast, Candida albicans

    Microsoft Academic Search

    Ismail

    1986-01-01

    C. albicans requires iron for growth and phenotypic development. When deprived of iron, mycelium and bud formation was suppressed. Survival of the organism was also reduced under iron-limiting conditions. The combination of elevated temperature and iron-deprivation further reduced phenotypic development and survival of the yeast. The combination of elevated temperature and iron starvation resulted in a decrease in both the

  18. Desiccation tolerance of iron bacteria biofilms on Mars regolith simulants

    Microsoft Academic Search

    Nina Feyh; Ulrich Szewzyk

    2010-01-01

    Iron oxidizing bacteria play an important role in the geological redox cycling of iron on earth. The redox change between Fe(II) and Fe(III) can be used for biological energy production [1]. Therefore iron oxidation in the iron rich martian soils may be or may have been microbially mediated. The microbial conversion of iron is considered to be an ancient form

  19. Deferiprone iron chelation as a novel therapy for experimental mucormycosis

    Microsoft Academic Search

    Ashraf S. Ibrahim; John E. Edwards Jr; Yue Fu; Brad Spellberg

    2006-01-01

    Objectives: Patients treated with the iron chelator deferoxamine are known to be more susceptible to mucormycosis. However, while deferoxamine is an iron chelator from the perspective of the human host, deferoxamine actually serves as a siderophore, delivering free iron to Rhizopus oryzae, the major cause of mucormycosis. Other iron chelators, including deferiprone, which do not deliver iron to R. oryzae

  20. Abnormal iron accumulation in the brain of neonatal hypotransferrinemic mice

    Microsoft Academic Search

    Atsushi Takeda; Keiko Takatsuka; James R Connor; Naoto Oku

    2001-01-01

    Transferrin is a plasma protein involved in iron delivery to tissues. To study iron transport into the brain under a transferrin deficiency, iron concentration and 59Fe uptake in the brain were measured in neonatal hypotransferrinemic (HP) mice at 7 days of age. Brain iron concentration of the HP mice, in which iron concentration was relatively high in the cerebral cortex

  1. Iron management in end-stage renal disease

    Microsoft Academic Search

    Steven Fishbane; John K. Maesaka

    1997-01-01

    One of the important components of successful anemia therapy in patients with end-stage renal disease (ESRD) treated with recombinant human erythropoietin is the maintenance of adequate available iron. To accomplish this task, iron status must be serially monitored and supplemental iron administered as required. Among nonuremic subjects, the body's iron supply is tightly conserved, and iron deficiency usually develops only

  2. Regulation of heme iron absorption by young children

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heme iron is an important source of dietary iron for children. Little is known of its absorption as only radio-isotopically labeled heme iron has been available to date. We have recently developed a method of intrinsically labeling bovine heme iron in vivo with the stable isotope iron-58. Our object...

  3. Structural basis for iron piracy by pathogenic Neisseria.

    PubMed

    Noinaj, Nicholas; Easley, Nicole C; Oke, Muse; Mizuno, Naoko; Gumbart, James; Boura, Evzen; Steere, Ashley N; Zak, Olga; Aisen, Philip; Tajkhorshid, Emad; Evans, Robert W; Gorringe, Andrew R; Mason, Anne B; Steven, Alasdair C; Buchanan, Susan K

    2012-03-01

    Neisseria are obligate human pathogens causing bacterial meningitis, septicaemia and gonorrhoea. Neisseria require iron for survival and can extract it directly from human transferrin for transport across the outer membrane. The transport system consists of TbpA, an integral outer membrane protein, and TbpB, a co-receptor attached to the cell surface; both proteins are potentially important vaccine and therapeutic targets. Two key questions driving Neisseria research are how human transferrin is specifically targeted, and how the bacteria liberate iron from transferrin at neutral pH. To address these questions, we solved crystal structures of the TbpA-transferrin complex and of the corresponding co-receptor TbpB. We characterized the TbpB-transferrin complex by small-angle X-ray scattering and the TbpA-TbpB-transferrin complex by electron microscopy. Our studies provide a rational basis for the specificity of TbpA for human transferrin, show how TbpA promotes iron release from transferrin, and elucidate how TbpB facilitates this process. PMID:22327295

  4. Structural basis for iron piracy by pathogenic Neisseria

    PubMed Central

    Noinaj, N.; Easley, N.C.; Oke, M.; Mizuno, N.; Gumbart, J.; Boura, E.; Steere, A.N.; Zak, O.; Aisen, P.; Tajkhorshid, E.; Evans, R.W.; Gorringe, A.R.; Mason, A.B.; Steven, A.C.; Buchanan, S.K.

    2012-01-01

    SUMMARY Neisseria are obligate human pathogens causing bacterial meningitis, septicemia, and gonorrhea. Neisseria require iron for survival and can extract it directly from human transferrin for transport across the outer membrane. The transport system consists of TbpA, an integral outer membrane protein, and TbpB, a co-receptor attached to the cell surface; both proteins are potentially important vaccine and therapeutic targets. Two key questions driving Neisseria research are: 1) how human transferrin is specifically targeted, and 2) how the bacteria liberate iron from transferrin at neutral pH. To address them, we solved crystal structures of the TbpA-transferrin complex and of the corresponding co-receptor TbpB. We characterized the TbpB-transferrin complex by small angle X-ray scattering and the TbpA-TbpB-transferrin complex by electron microscopy. Collectively, our studies provide a rational basis for the specificity of TbpA for human transferrin, show how TbpA promotes iron release from transferrin, and elucidate how TbpB facilitates this process. PMID:22327295

  5. Integrated Means Integrity

    ERIC Educational Resources Information Center

    Odegard, John D.

    1978-01-01

    Describes the operation of the Cessna Pilot Center (CPC) flight training systems. The program is based on a series of integrated activities involving stimulus, response, reinforcement and association components. Results show that the program can significantly reduce in-flight training time. (CP)

  6. Surface modification of high temperature iron alloys

    DOEpatents

    Park, J.H.

    1995-06-06

    A method and article of manufacture of a coated iron based alloy are disclosed. The method includes providing an iron based alloy substrate, depositing a silicon containing layer on the alloy surface while maintaining the alloy at a temperature of about 700--1200 C to diffuse silicon into the alloy surface and exposing the alloy surface to an ammonia atmosphere to form a silicon/oxygen/nitrogen containing protective layer on the iron based alloy. 13 figs.

  7. Correcting Iron Deficiencies in Grain Sorghum 

    E-print Network

    Livingston, Stephen; Coffman, Cloyce G.; Unruh, L. G.

    1996-02-20

    absorption spectrometry. Laboratories using the DTPH method of analysis, developed at Colorado State University, will encounter problems in obtaining accurate iron levels on soils with recent phosphorous amendments. The phosphorus will precipitate the low... the iron and potassium values. For iron testing, the soil samples should be evaluated by atomic absorption spectrometry. Laboratories using the DTPH method of analysis, developed at Colorado State University, will encounter problems in obtaining accurate...

  8. The Cu isotopic composition of iron meteorites

    NASA Astrophysics Data System (ADS)

    Bishop, Matthew Cole; Moynier, Frederic; Weinstein, Charlotte; Fraboulet, Jean-Gabriel; Wang, Kun; Foriel, Julien

    2012-02-01

    High-precision Cu isotopic compositions have been measured for the metal phase of 29 iron meteorites from various groups and for four terrestrial standards. The data are reported as the ?65Cu permil deviation of the 65Cu/63Cu ratio relative to the NIST SRM 976 standard. Terrestrial mantle rocks have a very narrow range of variations and scatter around zero. In contrast, iron meteorites show ?65Cu approximately 2.3‰ variations. Different groups of iron meteorites have distinct ?65Cu values. Nonmagmatic IAB-IIICD iron meteorites have similar ?65Cu (0.03 ± 0.08 and 0.12 ± 0.10, respectively), close to terrestrial values (approximately 0). The other group of nonmagmatic irons, IIE, is isotopically distinct (-0.69 ± 0.15). IVB is the iron meteorite group with the strongest elemental depletion in Cu and samples in this group are enriched in the lighter isotope (?65Cu down to -2.26‰). Evaporation should have produced an enrichment in 65Cu over 63Cu (?65Cu >0) and can therefore be ruled out as a mechanism for volatile loss in IVB meteorites. In silicate-bearing iron meteorites, ?17O correlates with ?65Cu. This correlation between nonmass-dependent and mass-dependent parameters suggests that the Cu isotopic composition of iron meteorites has not been modified by planetary differentiation to a large extent. Therefore, Cu isotopic ratios can be used to confirm genetic links. Cu isotopes thus confirm genetic relationships between groups of iron meteorites (e.g., IAB and IIICD; IIIE and IIIAB); and between iron meteorites and chondrites (e.g., IIE and H chondrites). Several genetic connections between iron meteorites groups are confirmed by Cu isotopes, (e.g., IAB and IIICD; IIIE and IIIAB); and between iron meteorites and chondrites (e.g., IIE and H chondrites).

  9. Effects of Iron Chelators, Iron Salts, and Iron Oxide Nanoparticles on the Proliferation and the Iron Content of Oligodendroglial OLN-93 Cells

    Microsoft Academic Search

    Michaela Hohnholt; Mark Geppert; Ralf Dringen

    2010-01-01

    The oligodendroglial cell line OLN-93 was used as model system to investigate the consequences of iron deprivation or iron\\u000a excess on cell proliferation. Presence of ferric or ferrous iron chelators inhibited the proliferation of OLN-93 cells in\\u000a a time and concentration dependent manner, while the application of a molar excess of ferric ammonium citrate (FAC) prevented\\u000a the inhibition of proliferation

  10. Study of iron mononitride thin films

    SciTech Connect

    Tayal, Akhil, E-mail: mgupta@csr.res.in; Gupta, Mukul, E-mail: mgupta@csr.res.in; Phase, D. M., E-mail: mgupta@csr.res.in; Reddy, V. R., E-mail: mgupta@csr.res.in; Gupta, Ajay, E-mail: mgupta@csr.res.in [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore,-452001 (India)

    2014-04-24

    In this work we have studied the crystal structural and local ordering of iron and nitrogen in iron mononitride thin films prepared using dc magnetron sputtering at sputtering power of 100W and 500W. The films were sputtered using pure nitrogen to enhance the reactivity of nitrogen with iron. The x-ray diffraction (XRD), conversion electron Mössbauer spectroscopy (CEMS) and soft x-ray absorption spectroscopy (SXAS) studies shows that the film crystallizes in ZnS-type crystal structure.

  11. Iron-Chelating Therapy for Transfusional Iron Overload

    PubMed Central

    Brittenham, Gary M.

    2011-01-01

    A 16-year-old boy with sickle cell anemia undergoes routine screening with transcranial Doppler ultrasonography to assess the risk of stroke. This examination shows an abnormally elevated blood-flow velocity in the middle cerebral artery. The hemoglobin level is 7.2 g per deciliter, the reticulocyte count is 12.5%, and the fetal hemoglobin level is 8.0%. Long-term treatment with red-cell transfusion is initiated to prevent stroke. A hematologist recommends prophylactic iron-chelating therapy. PMID:21226580

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

    E-print Network

    Gupton, Paul Stephen

    1961-01-01

    THE MAGNETIC PROPERTIES OF THE IRON-RICH, IRON-NICKEL-ZINC ALLOYS A Thesis By Paul Stephen Gupton Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE January 1961 Major Subject Nuclear Engineering THE MAGNETIC PROPERTIES OF THE IRON-RICH, IRON-NICKEL-ZINC ALLOYS A Thesis By Paul Stephen Gupton Approved as to style and content by: (Chairman of Ittee) Head of Oepartment...

  13. Kinetics of dissolution and bio-availability of iron in amorphous siliceous iron oxides

    E-print Network

    Seaman, John C.

    1990-01-01

    KINETICS OF DISSOLUTION AND BIO-AVAILABILITY OF IRON IN AMORPHOUS SILICEOUS IRON OXIDES A Thesis By John C. Seaman Submitted to the Graduate College of Texas AIIM University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE December 1990 Major Subject: Soil Science KINETICS OF DISSOLUTION AND BIO-AVAILABILITY OF IRON IN AMORPHOUS SILICEOUS IRON OXIDES A Thesis By John C. Seaman Approved as to style and content by: Richard H. Loeppert (Chair of Committee...

  14. Secreted Pyomelanin of Legionella pneumophila Promotes Bacterial Iron Uptake and Growth under Iron-Limiting Conditions

    PubMed Central

    Zheng, Huaixin; Chatfield, Christa H.; Liles, Mark R.

    2013-01-01

    Iron acquisition is critical to the growth and virulence of Legionella pneumophila. Previously, we found that L. pneumophila uses both a ferrisiderophore pathway and ferrous iron transport to obtain iron. We now report that two molecules secreted by L. pneumophila, homogentisic acid (HGA) and its polymerized variant (HGA-melanin, a pyomelanin), are able to directly mediate the reduction of various ferric iron salts. Furthermore, HGA, synthetic HGA-melanin, and HGA-melanin derived from bacterial supernatants enhanced the ability of L. pneumophila and other species of Legionella to take up radiolabeled iron. Enhanced iron uptake was not observed with a ferrous iron transport mutant. Thus, HGA and HGA-melanin mediate ferric iron reduction, with the resulting ferrous iron being available to the bacterium for uptake. Upon further testing of L. pneumophila culture supernatants, we found that significant amounts of ferric and ferrous iron were associated with secreted HGA-melanin. Importantly, a pyomelanin-containing fraction obtained from a wild-type culture supernatant was able to stimulate the growth of iron-starved legionellae. That the corresponding supernatant fraction obtained from a nonpigmented mutant culture did not stimulate growth demonstrated that HGA-melanin is able to both promote iron uptake and enhance growth under iron-limiting conditions. Indicative of a complementary role in iron acquisition, HGA-melanin levels were inversely related to the levels of siderophore activity. Compatible with a role in the ecology and pathogenesis of L. pneumophila, HGA and HGA-melanin were effective at reducing and releasing iron from both insoluble ferric hydroxide and the mammalian iron chelates ferritin and transferrin. PMID:23980114

  15. Iron metabolism in higher plants. The influence of nutrient iron on bean leaf lipoxygenase

    Microsoft Academic Search

    Rodney F. Boyer; Jane R. VanderPloeg

    1986-01-01

    Bean plants (Phaseolus vulgaris L.) were cultured in nutrient solutions containing three concentrations of iron. The leaves of plants grown with a limiting supply of iron contained reduced levels of protein, chlorophyll and the iron?containing enzyme, lipoxygenase (EC 1.13.11.12). Measurements of lipoxygenase made on leaf crude extracts did not correlate with iron supply; however, upon purification of the enzyme by

  16. The Treatment of Iron-Deficiency Anemia with Intravenous Iron Dextran

    Microsoft Academic Search

    SIDNEY MARCHASIN

    1964-01-01

    IN THE THERAPY of iron-deficiency anemia, iron given orally is safe, ef- fective, inexpensive, and is usually the treatment of choice, but occasional- ly when a rapid replenishment of iron stores is desired, administration by the parenteral route is indicated. Heath, Strauss and Castle,1 in 1938, showed that when 16-32 mg. of iron as ferric ammonium citrate is injected subcuta-

  17. THE DETERMINATION OF SERUM IRON AFTER THE INTRAVENOUS INJECTION OF IRON-DEXTRAN

    Microsoft Academic Search

    D. Webster

    1960-01-01

    A rapid technique for the determination of iron in serum, after the intravenous injection of iron-dextran, is presented.Dithionite is used for the reduction of ferric to ferrous iron.The use of a detergent solution enables protein precipitation to be omitted.The iron reagent, 4: 7-diphenyl-1: 10-phenanthroline, and its ferrous complex are both soluble in the dilute detergent solution.Lipaemic serum can be used

  18. Lactoferrin efficacy versus ferrous sulfate in curing iron deficiency and iron deficiency anemia in pregnant women

    Microsoft Academic Search

    Rosalba Paesano; Francesca Berlutti; Miriam Pietropaoli; Fabrizio Pantanella; Enrica Pacifici; William Goolsbee; Piera Valenti

    2010-01-01

    Iron deficiency (ID) and iron deficiency anemia (IDA) are the most common iron disorders throughout the world. ID and IDA,\\u000a particularly caused by increased iron requirements during pregnancy, represent a high risk for preterm delivery, fetal growth\\u000a retardation, low birth weight, and inferior neonatal health. Oral administration of ferrous sulfate to cure ID and IDA in\\u000a pregnancy often fails to

  19. Influence of iron-saturation of plasma transferrin in iron distribution in the brain

    Microsoft Academic Search

    Atsushi Takeda; Keiko Takatsuka; Naoki Sotogaku; Naoto Oku

    2002-01-01

    Based on the evidence that iron distribution in the peripheral tissues is changed by iron-saturation of plasma transferrin, the influence of iron-saturation of plasma transferrin in iron delivery to the brain was examined. Mouse plasma was pre-incubated with ferric chloride in citrate buffer to saturate transferrin and then incubated with 59FeCl3. Peak retention time of 59Fe was transferred from the

  20. Iron requirement and siderophore production in Rhizobium ciceri during growth on an iron-deficient medium

    Microsoft Academic Search

    E. L. Berraho; D. Lesueur; H. G. Diem; A. Sasson

    1997-01-01

    Under conditions of iron limitation many rhizospheric bacteria produce siderophores, ferric iron-specific ligands, which may enhance plant growth by increasing the availability of iron near the roots. Thirty-five strains of Rhizobium ciceri, specific to chickpea (Cicer arietinum L.), were screened for their ability to grow on iron-deficient medium and to produce siderophores. Maximal growth of all strains previously depleted in

  1. Biosynthesis and characterization of layered iron phosphate

    NASA Astrophysics Data System (ADS)

    Zhou, Weijia; He, Wen; Wang, Meiting; Zhang, Xudong; Li, Peng; Yan, Shunpu; Tian, Xiuying; Sun, Xianan; Han, Xiuxiu

    2008-12-01

    Layered iron phosphate with uniform morphology has been synthesized by a precipitation method with yeast cells as a biosurfactant. The yeast cells are used to regulate the nucleation and growth of layered iron phosphate. The uniform layered structure is characterized by small-angle x-ray diffraction (SAXD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses. Fourier transform infrared spectroscopy (FT-IR) is used to analyze the chemical bond linkages in organic-inorganic hybrid iron phosphate. The likely synthetic mechanism of nucleation and oriented growth is discussed. The electrical conductivity of hybrid iron phosphate heat-treated at different temperatures is presented.

  2. Method for producing iron-based catalysts

    DOEpatents

    Farcasiu, Malvina (Pittsburgh, PA); Kaufman, Phillip B. (Library, PA); Diehl, J. Rodney (Pittsburgh, PA); Kathrein, Hendrik (McMurray, PA)

    1999-01-01

    A method for preparing an acid catalyst having a long shelf-life is provided comprising doping crystalline iron oxides with lattice-compatible metals and heating the now-doped oxide with halogen compounds at elevated temperatures. The invention also provides for a catalyst comprising an iron oxide particle having a predetermined lattice structure, one or more metal dopants for said iron oxide, said dopants having an ionic radius compatible with said lattice structure; and a halogen bound with the iron and the metal dopants on the surface of the particle.

  3. Iron oxyhydroxide mineralization on microbial extracellular polysaccharides

    SciTech Connect

    Chan, Clara S.; Fakra, Sirine C.; Edwards, David C.; Emerson, David; Banfield, Jillian F.

    2010-06-22

    Iron biominerals can form in neutral pH microaerophilic environments where microbes both catalyze iron oxidation and create polymers that localize mineral precipitation. In order to classify the microbial polymers that influence FeOOH mineralogy, we studied the organic and mineral components of biominerals using scanning transmission X-ray microscopy (STXM), micro X-ray fluorescence ({mu}XRF) microscopy, and high-resolution transmission electron microscopy (HRTEM). We focused on iron microbial mat samples from a creek and abandoned mine; these samples are dominated by iron oxyhydroxide-coated structures with sheath, stalk, and filament morphologies. In addition, we characterized the mineralized products of an iron-oxidizing, stalk-forming bacterial culture isolated from the mine. In both natural and cultured samples, microbial polymers were found to be acidic polysaccharides with carboxyl functional groups, strongly spatially correlated with iron oxyhydroxide distribution patterns. Organic fibrils collect FeOOH and control its recrystallization, in some cases resulting in oriented crystals with high aspect ratios. The impact of polymers is particularly pronounced as the materials age. Synthesis experiments designed to mimic the biomineralization processes show that the polysaccharide carboxyl groups bind dissolved iron strongly but release it as mineralization proceeds. Our results suggest that carboxyl groups of acidic polysaccharides are produced by different microorganisms to create a wide range of iron oxyhydroxide biomineral structures. The intimate and potentially long-term association controls the crystal growth, phase, and reactivity of iron oxyhydroxide nanoparticles in natural systems.

  4. Processing of Goethitic Iron Ore Fines

    NASA Astrophysics Data System (ADS)

    Sharma, J.; Sharma, T.; Mandre, N. R.

    2015-05-01

    In the present investigation an attempt has been made to beneficiate goethitic iron ore containing 59.02 % Iron, 6.51 % Alumina, 4.79 % Silica, 0.089 % Phosphorus with 7.11 % loss on ignition. For this purpose, different beneficiation techniques such as gravity and magnetic separation processes have been employed. During the process two conceptual flow sheets were also developed for the beneficiation of goethite iron ore fines. In the prsent work it was possible to enhance grade of iron to 63.35, 63.18, and 65.35 % from Jigging, Multi Gravity Separation (MGS) and Wet High Intensity Magnetic Separator (WHIMS) respectively.

  5. Mechanisms of iron import in anthrax.

    PubMed

    Honsa, Erin Sarah; Maresso, Anthony William

    2011-06-01

    During an infection, bacterial pathogens must acquire iron from the host to survive. However, free iron is sequestered in host proteins, which presents a barrier to iron-dependent bacterial replication. In response, pathogens have developed mechanisms to acquire iron from the host during infection. Interestingly, a significant portion of the iron pool is sequestered within heme, which is further bound to host proteins such as hemoglobin. The copious amount of heme-iron makes hemoglobin an ideal molecule for targeted iron uptake during infection. While the study of heme acquisition is well represented in Gram-negative bacteria, the systems and mechanism of heme uptake in Gram-positive bacteria has only recently been investigated. Bacillus anthracis, the causative agent of anthrax disease, represents an excellent model organism to study iron acquisition processes owing to a multifaceted lifecycle consisting of intra- and extracellular phases and a tremendous replicative potential upon infection. This review provides an in depth description of the current knowledge of B. anthracis iron acquisition and applies these findings to a general understanding of how pathogenic Gram-positive bacteria transport this critical nutrient during infection. PMID:21258843

  6. Iron mobilization using chelation and phlebotomy.

    PubMed

    Flaten, Trond Peder; Aaseth, Jan; Andersen, Ole; Kontoghiorghes, George J

    2012-06-01

    Knowledge of the basic mechanisms involved in iron metabolism has increased greatly in recent years, improving our ability to deal with the huge global public health problems of iron deficiency and overload. Several million people worldwide suffer iron overload with serious clinical implications. Iron overload has many different causes, both genetic and environmental. The two most common iron overload disorders are hereditary haemochromatosis and transfusional siderosis, which occurs in thalassaemias and other refractory anaemias. The two most important treatment options for iron overload are phlebotomy and chelation. Phlebotomy is the initial treatment of choice in haemochromatosis, while chelation is a mainstay in the treatment of transfusional siderosis. The classical iron chelator is deferoxamine (Desferal), but due to poor gastrointestinal absorption it has to be administered intravenously or subcutaneously, mostly on a daily basis. Thus, there is an obvious need to find and develop new effective iron chelators for oral use. In later years, particularly two such oral iron chelators have shown promise and have been approved for clinical use, namely deferiprone (Ferriprox) and deferasirox (Exjade). Combined subcutaneous (deferoxamine) and oral (deferiprone) treatment seems to hold particular promise. PMID:22565013

  7. Evidence for a hydrologically controlled iron cycle in acidic and iron rich sediments

    Microsoft Academic Search

    Christian Blodau

    2004-01-01

    Retention of ferrous iron at the interface between ground- and surface water is crucial for the acidity balance of lakes influenced by acid mine drainage. Iron budgets were developed for two sediments in areas of differential groundwater inflow (ca. 1 and 10 L m –2 d –1). In both areas iron was sedimented as schwertmannite (Fe 8O 8(OH) x(SO 4)

  8. Desferrioxamine-mediated Iron Uptake in Saccharomyces cerevisiae EVIDENCE FOR TWO PATHWAYS OF IRON UPTAKE*

    E-print Network

    Botstein, David

    Medical Institute, Stanford, California 94305-5428 In the yeast Saccharomyces cerevisiae, uptake of iron. Deletion of ARN3 did not prevent yeast from using ferrioxamine B as an iron source; however, deletion microbes to man have developed mechanisms for obtain- ing iron from the environment. The budding yeast

  9. The distribution of iron in the brain: A phylogenetic analysis using iron histochemistry

    Microsoft Academic Search

    Gregory L. Erb; David L. Osterbur; Steven M. LeVine

    1996-01-01

    Histochemical procedures can be used to detect the cellular distribution of iron in the brain. The objective of the present study was to determine if the cellular distribution of iron enrichment is conserved between animals on different branches of the phylogenetic tree. This information can facilitate our understanding of the role of iron enrichment in cells of the brain. The

  10. IRON "BIOFORTIFICATION" OF TROPICAL MAIZE TO REDUCE HUMAN IRON DEFFICIENCY IN WEST AFRICA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Iron deficiency is estimated to affect over one-half the world population. Improving the nutritional quality of staple food crops by the development of genotypes with high bioavailable iron represents a sustainable and cost effective approach to alleviating iron malnutrition. Forty-nine elite late m...

  11. Serum bleomycin-detectable iron in patients with thalassemia major with normal range of serum iron.

    PubMed

    Han, K E; Okada, S

    1995-06-01

    "Free" iron, a potentially radical-generating low mass iron, and not found in normal human blood, was increased in the serum of blood-transfused thalassemia major patients seen in the Yangon General Hospital, Yangon, Myanmar (Burma). The low mass iron was detected by the bleomycin assay. Fifty-one blood samples were analyzed (from 28 males and 23 females). High "free" iron was detected in 47 sera samples from thalassemia patients. Serum ferritin, which reflects the body store iron, was higher than the normal range (10-200 ng/ml) in 49 patients. On the other hand, serum iron of 39 sera samples fell within the normal range (50-150 micrograms/dl). Four were less than 50 micrograms/dl and eight were more than 150 micrograms/dl. Almost all the patients' sera of normal or higher serum iron level contained "free" iron. Thus, almost all the sera from thalassemic patients from Myanmar contain bleomycin-detectable iron, even when serum iron is within the normal range. In developing countries where undernutrition is prevalent (serum albumin in these patients was 3.6 +/- 0.4 g/dl, P < 0.0001 vs. control value of 4.0 - 4.8 g/dl), normal serum iron does not preclude the presence of free iron in the serum. PMID:7545860

  12. Labile plasma iron in iron overload: redox activity and susceptibility to chelation

    Microsoft Academic Search

    Breno P. Esposito; William Breuer; Pornpan Sirankapracha; Pensri Pootrakul; Chaim Hershko; Z. Ioav Cabantchik

    2003-01-01

    Plasma non-transferrin-bound-iron (NTBI) is believed to be responsible for cata- lyzing the formation of reactive radicals in the circulation of iron overloaded sub- jects, resulting in accumulation of oxida- tion products. We assessed the redox active component of NTBI in the plasma of healthy and -thalassemic patients. The labile plasma iron (LPI) was deter- mined with the fluorogenic dihydrorho- damine

  13. Reactive Iron and Iron-Reducing Bacteria in Louisiana Continental Shelf Sediments

    EPA Science Inventory

    The Mississippi and Atchafalaya Rivers release sediments containing 15 x 106 t of iron onto the Louisiana continental shelf (LCS) each year. Iron oxides reaching the seafloor may be utilized as electron acceptors by iron-reducing bacteria for organic matter oxidation or become r...

  14. Bordetella pertussis FbpA Binds Both Unchelated Iron and Iron Siderophore Complexes

    PubMed Central

    2015-01-01

    Bordetella pertussis is the causative agent of whooping cough. This pathogenic bacterium can obtain the essential nutrient iron using its native alcaligin siderophore and by utilizing xeno-siderophores such as desferrioxamine B, ferrichrome, and enterobactin. Previous genome-wide expression profiling identified an iron repressible B. pertussis gene encoding a periplasmic protein (FbpABp). A previously reported crystal structure shows significant similarity between FbpABp and previously characterized bacterial iron binding proteins, and established its iron-binding ability. Bordetella growth studies determined that FbpABp was required for utilization of not only unchelated iron, but also utilization of iron bound to both native and xeno-siderophores. In this in vitro solution study, we quantified the binding of unchelated ferric iron to FbpABp in the presence of various anions and importantly, we demonstrated that FbpABp binds all the ferric siderophores tested (native and xeno) with ?M affinity. In silico modeling augmented solution data. FbpABp was incapable of iron removal from ferric xeno-siderophores in vitro. However, when FbpABp was reacted with native ferric-alcaligin, it elicited a pronounced change in the iron coordination environment, which may signify an early step in FbpABp-mediated iron removal from the native siderophore. To our knowledge, this is the first time the periplasmic component of an iron uptake system has been shown to bind iron directly as Fe3+ and indirectly as a ferric siderophore complex. PMID:24873326

  15. Iron Supplementation in Suckling Piglets: How to Correct Iron Deficiency Anemia without Affecting Plasma Hepcidin Levels

    PubMed Central

    Starzy?ski, Rafa? R.; Laarakkers, Coby M. M.; Tjalsma, Harold; Swinkels, Dorine W.; Pieszka, Marek; Sty?, Agnieszka; Mickiewicz, Micha?; Lipi?ski, Pawe?

    2013-01-01

    The aim of the study was to establish an optimized protocol of iron dextran administration to pig neonates, which better meets the iron demand for erythropoiesis. Here, we monitored development of red blood cell indices, plasma iron parameters during a 28-day period after birth (till the weaning), following intramuscular administration of different concentrations of iron dextran to suckling piglets. To better assess the iron status we developed a novel mass spectrometry assay to quantify pig plasma levels of the iron-regulatory peptide hormone hepcidin-25. This hormone is predominantly secreted by the liver and acts as a negative regulator of iron absorption and reutilization. The routinely used protocol with high amount of iron resulted in the recovery of piglets from iron deficiency but also in strongly elevated plasma hepcidin-25 levels. A similar protocol with reduced amounts of iron improved hematological status of piglets to the same level while plasma hepcidin-25 levels remained low. These data show that plasma hepcidin-25 levels can guide optimal dosing of iron treatment and pave the way for mixed supplementation of piglets starting with intramuscular injection of iron dextran followed by dietary supplementation, which could be efficient under condition of very low plasma hepcidin-25 level. PMID:23737963

  16. IRON AND ATHEROSCLEROSIS: IRON CHELATORS DECREASE ADHESION OF MONOCYTES TO VASCULAR ENDOTHELIUM

    Microsoft Academic Search

    R. Kartikasari; N. A. Georgiou; B. Sweder van Asbeck; I. J. M. Marx

    2003-01-01

    Besides the fact that it is a vital element in life, iron may also participate in diverse pathological processes. It has been hypothesised that iron is involved in the development of atherosclerosis and related cardiovascular diseases. Several epidemiological studies as well as in vivo and in vitro experiments are in favour for this iron hypothesis, although some studies have yielded

  17. FeCycle: Attempting an iron biogeochemical budget from a mesoscale SF6 tracer experiment in unperturbed low iron waters

    E-print Network

    Wilhelm, Steven W.

    , sinks of iron from, and rates of iron recycling within, the surface mixed layer. A pelagic iron budgetFeCycle: Attempting an iron biogeochemical budget from a mesoscale SF6 tracer experiment in unperturbed low iron waters P. W. Boyd,1 C. S. Law,2 D. A. Hutchins,3 E. R. Abraham,2 P. L. Croot,4 M. Ellwood

  18. Iron and iron chelating agents modulate Mycobacterium tuberculosis growth and monocyte-macrophage viability and effector functions

    Microsoft Academic Search

    Nicole Edmondson; Kathleen D. Eisenach; Liza Bornman

    2005-01-01

    Excess of iron promotes Mycobacterium tuberculosis infection, its replication and progression to clinical disease and death from tuberculosis. Chelation of iron may reduce M. tuberculosis replication, restore host defence mechanisms and it could constitute an application in the prevention and treatment strategies where both iron overload and tuberculosis are prevalent. We investigated the effect of iron and iron chelating agents,

  19. Iron chelator deferoxamine alters iron-regulatory genes and proteins and suppresses osteoblast phenotype in fetal rat calvaria cells

    Microsoft Academic Search

    Jonathan G. Messer; Paula T. Cooney; Deborah E. Kipp

    2010-01-01

    There are few studies describing the extent to which low iron status affects osteoblastogenesis, despite evidence that iron deficiency produces adverse effects on bone density. The purpose of this study was to evaluate alterations in intracellular iron status by measuring iron-regulated gene and protein expression and to describe development of osteoblast phenotype in primary cells treated with iron chelator deferoxamine

  20. Cementite Solidification in Cast Iron

    NASA Astrophysics Data System (ADS)

    Coronado, J. J.; Sinatora, A.; Albertin, E.

    2014-06-01

    Two hypereutectic cast irons (5.01 pct Cr and 5.19 pct V) were cast and the polished surfaces of test pieces were deep-etched and analyzed via scanning electron microscopy. The results show that graphite lamellae intersect the cementite and a thin austenite film nucleates and grows on the cementite plates. For both compositions, graphite and cementite can coexist as equilibrium phases, with the former always nucleating and growing first. The eutectic carbides grow from the austenite dendrites in a direction perpendicular to the primary plates.

  1. Iron transfer between ferritin molecules

    Microsoft Academic Search

    E. R. Bauminger; P. M. Harrison; D. Hechel; I. Nowik; A. Treffry

    1992-01-01

    When ferritin solutions containing 8–1257Fe atoms\\/molecule are mixed after iron loading, with ferritin containing a small56Fe core (56Fe-ferritins) or with an equal volume of NaCl solution (controls) and the mixtures are frozen in liquid nitrogen (LN) at specified\\u000a times, the spectra of the56Fe-ferritins show that almost all57Fe is attached to large clusters, whereas in the controls all57Fe is present as

  2. Picosecond dynamics of iron proteins

    PubMed Central

    Huppert, D.; Straub, K. D.; Rentzepis, P. M.

    1977-01-01

    The excitation of hemoproteins containing either Fe2+ or Fe3+ with a picosecond light pulse resulted in the bleaching and recovery of the iron absorbance bands within 6 psec. A new absorbance band also was observed whose formation and decay rate of less than 6 psec suggests that it is probably due to S1?Sn absorbance. The Soret band relaxation time is deduced to be ?0.5 psec whereas the free base hemoprotein does not show any of the above fast-decay characteristics. Therefore, there is a strong influence of the metal on the energy dissipation process. Images PMID:16592438

  3. Increased serum iron and iron saturation without liver iron accumulation distinguish chronic hepatitis C from other chronic liver diseases

    Microsoft Academic Search

    N. Arber; F. M. Konikoff; M. Moshkowitz; M. Baratz; A. Hallak; M. Santo; Z. Halpern; H. Weiss; T. Gilat

    1994-01-01

    One hundred twenty-three patients with chronic liver diseases of various etiologies were evaluated for their iron status. The patients were divided into four distinct groups: chronic hepatitis C (63), chronic hepatitis B (14), B + C (3) and nonviral chronic liver diseases (43). In 107 patients (87%) the chronic liver disease was confirmed by biopsy. Mean serum iron (±sd) levels

  4. Green tea catechins as brain-permeable, non toxic iron chelators to "iron out iron" from the brain.

    PubMed

    Mandel, S; Weinreb, O; Reznichenko, L; Kalfon, L; Amit, T

    2006-01-01

    Evidence to link abnormal metal (iron, copper and zinc) metabolism and handling with Parkinson's and Alzheimer's diseases pathology has frequently been reported. The capacity of free iron to enhance and promote the generation of toxic reactive oxygen radicals has been discussed numerous times. Metal chelation has the potential to prevent iron-induced oxidative stress and aggregation of alpha-synuclein and beta-amyloid peptides. The efficacy of iron chelators depends on their ability to penetrate the subcellular compartments and cellular membranes where iron dependent free radicals are generated. Thus, natural, non-toxic, brain permeable neuroprotective drugs, are preferentially advocated for "ironing out iron" from those brain areas where it preferentially accumulates in neurodegenerative diseases. This review will discuss the most recent findings from in vivo and in vitro studies concerning the transitional metal (iron and copper) chelating property of green tea, and its major polyphenol, (-)-epigallocatechin-3-gallate with respect to their potential for the treatment of neurodegenerative diseases. PMID:17447435

  5. 49 CFR 192.275 - Cast iron pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Welding § 192.275 Cast iron pipe. (a) Each caulked bell and spigot joint in cast iron pipe must be sealed with mechanical leak clamps. (b) Each mechanical joint in cast iron pipe must have a gasket made of a...

  6. Anionic Homopolymers Efficiently Target Zerovalent Iron Particles to

    E-print Network

    of microscale carbonyl iron powder suspensions modified with anionic homopolymers was studied in waterAnionic Homopolymers Efficiently Target Zerovalent Iron Particles to Hydrophobic Contaminants (DNAPL) contaminants. By comparing iron particle transport in uncontaminated columns with those

  7. 20. INTERIOR VIEW WITH IRON POURERS FILLING COMPLETED MOLDS ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. INTERIOR VIEW WITH IRON POURERS FILLING COMPLETED MOLDS ON GREY IRON UNIT NO. 1 MOLD CONVEYOR. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  8. 49 CFR 236.532 - Strap iron inductor; use restricted.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Strap iron inductor; use restricted. 236.532...Instructions; Roadway § 236.532 Strap iron inductor; use restricted. No railroad shall use strap iron inductor or other roadway element...

  9. 40 CFR 721.10357 - Iron, citrate phosphate potassium complexes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Iron, citrate phosphate potassium complexes...Specific Chemical Substances § 721.10357 Iron, citrate phosphate potassium complexes...1) The chemical substance identified as iron, citrate phosphate potassium...

  10. 40 CFR 721.10357 - Iron, citrate phosphate potassium complexes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Iron, citrate phosphate potassium complexes...Specific Chemical Substances § 721.10357 Iron, citrate phosphate potassium complexes...1) The chemical substance identified as iron, citrate phosphate potassium...

  11. 21 CFR 573.580 - Iron-choline citrate complex.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 6 2013-04-01 2013-04-01 false Iron-choline citrate complex. 573.580 Section...ANIMALS Food Additive Listing § 573.580 Iron-choline citrate complex. Iron-choline citrate complex made by reacting...

  12. 49 CFR 236.532 - Strap iron inductor; use restricted.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Strap iron inductor; use restricted. 236.532...Instructions; Roadway § 236.532 Strap iron inductor; use restricted. No railroad shall use strap iron inductor or other roadway element...

  13. 21 CFR 573.580 - Iron-choline citrate complex.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 6 2014-04-01 2014-04-01 false Iron-choline citrate complex. 573.580 Section...ANIMALS Food Additive Listing § 573.580 Iron-choline citrate complex. Iron-choline citrate complex made by reacting...

  14. 40 CFR 721.10357 - Iron, citrate phosphate potassium complexes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Iron, citrate phosphate potassium complexes...Specific Chemical Substances § 721.10357 Iron, citrate phosphate potassium complexes...1) The chemical substance identified as iron, citrate phosphate potassium...

  15. 21 CFR 573.580 - Iron-choline citrate complex.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 6 2012-04-01 2012-04-01 false Iron-choline citrate complex. 573.580 Section...ANIMALS Food Additive Listing § 573.580 Iron-choline citrate complex. Iron-choline citrate complex made by reacting...

  16. 39. Detail view of No. 2 Furnace iron runner; rod ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    39. Detail view of No. 2 Furnace iron runner; rod or poker at right was used to unplug iron notch. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

  17. 19. INTERIOR VIEW WITH IRON POURERS FILLING COMPLETED MOLDS ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. INTERIOR VIEW WITH IRON POURERS FILLING COMPLETED MOLDS ON GREY IRON UNIT NO. 1 MOLD CONVEYOR. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  18. 49 CFR 236.532 - Strap iron inductor; use restricted.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Strap iron inductor; use restricted. 236.532...Instructions; Roadway § 236.532 Strap iron inductor; use restricted. No railroad shall use strap iron inductor or other roadway element...

  19. 21 CFR 573.580 - Iron-choline citrate complex.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 6 2010-04-01 2010-04-01 false Iron-choline citrate complex. 573.580 Section...ANIMALS Food Additive Listing § 573.580 Iron-choline citrate complex. Iron-choline citrate complex made by reacting...

  20. 49 CFR 236.532 - Strap iron inductor; use restricted.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Strap iron inductor; use restricted. 236.532...Instructions; Roadway § 236.532 Strap iron inductor; use restricted. No railroad shall use strap iron inductor or other roadway element...

  1. 21 CFR 172.370 - Iron-choline citrate complex.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 3 2010-04-01 2009-04-01 true Iron-choline citrate complex. 172.370 Section...Dietary and Nutritional Additives § 172.370 Iron-choline citrate complex. Iron-choline citrate complex made by reacting...

  2. 49 CFR 236.532 - Strap iron inductor; use restricted.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Strap iron inductor; use restricted. 236.532...Instructions; Roadway § 236.532 Strap iron inductor; use restricted. No railroad shall use strap iron inductor or other roadway element...

  3. 21 CFR 573.580 - Iron-choline citrate complex.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 6 2011-04-01 2011-04-01 false Iron-choline citrate complex. 573.580 Section...ANIMALS Food Additive Listing § 573.580 Iron-choline citrate complex. Iron-choline citrate complex made by reacting...

  4. Iron and learning potential in childhood.

    PubMed Central

    Lozoff, B.

    1989-01-01

    Cognitive function. There is reasonably good evidence that mental and motor developmental test scores are lower among infants with iron deficiency anemia. Although the research on cognitive function in iron deficient older children and adults is sparse and diverse, it suggests that there may be alterations in attentional processes associated with iron deficiency. Iron therapy has not yet been shown effective in completely correcting many of the observed disturbances. Although some aspects of cognitive function seem to change with iron therapy, lower developmental. I.Q., and achievement test scores have still been noted after treatment. The behavioral effects of iron-deficiency anemia may be due to changes in neurotransmission. However, the biochemical bases are not yet completely understood. Noncognitive disturbances. A variety of noncognitive alterations during infant developmental testing has also been observed, including failure to respond to test stimuli, short attention span, unhappiness, increased fearfulness, withdrawal from the examiner, and increased body tension. Exploratory analyses suggest that such behavioral abnormalities may account for poor developmental test performance in infants with iron deficiency anemia. These studies indicate the fruitfulness of examining noncognitive aspects of behavior such as affect, attention, and activity, in addition to specific cognitive processes. Activity and work capacity: There has been a steady accumulation of evidence that iron-deficiency anemia limits maximal physical performance, submaximal endurance, and spontaneous activity in the adult, resulting in diminished work productivity with attendant economic losses. The relative importance of central and peripheral mechanisms underlying these effects, the extent to which anemia or iron deficiency separate from anemia is responsible, and the counterpart in infants and children remain to be established. This essay has examined recent evidence from research on central nervous system biochemistry and from human studies that iron deficiency adversely affects behavior by impairing cognitive function, producing noncognitive disturbances, and limiting activity and work capacity. The body of research taken as a whole provides increasingly persuasive arguments for intensifying efforts to prevent and treat iron deficiency anemia. PMID:2698245

  5. A Computational Model of Liver Iron Metabolism

    PubMed Central

    Mitchell, Simon; Mendes, Pedro

    2013-01-01

    Iron is essential for all known life due to its redox properties; however, these same properties can also lead to its toxicity in overload through the production of reactive oxygen species. Robust systemic and cellular control are required to maintain safe levels of iron, and the liver seems to be where this regulation is mainly located. Iron misregulation is implicated in many diseases, and as our understanding of iron metabolism improves, the list of iron-related disorders grows. Recent developments have resulted in greater knowledge of the fate of iron in the body and have led to a detailed map of its metabolism; however, a quantitative understanding at the systems level of how its components interact to produce tight regulation remains elusive. A mechanistic computational model of human liver iron metabolism, which includes the core regulatory components, is presented here. It was constructed based on known mechanisms of regulation and on their kinetic properties, obtained from several publications. The model was then quantitatively validated by comparing its results with previously published physiological data, and it is able to reproduce multiple experimental findings. A time course simulation following an oral dose of iron was compared to a clinical time course study and the simulation was found to recreate the dynamics and time scale of the systems response to iron challenge. A disease state simulation of haemochromatosis was created by altering a single reaction parameter that mimics a human haemochromatosis gene (HFE) mutation. The simulation provides a quantitative understanding of the liver iron overload that arises in this disease. This model supports and supplements understanding of the role of the liver as an iron sensor and provides a framework for further modelling, including simulations to identify valuable drug targets and design of experiments to improve further our knowledge of this system. PMID:24244122

  6. Iron indices in bottlenose dolphins (Tursiops truncatus).

    PubMed

    Mazzaro, Lisa M; Johnson, Shawn P; Fair, Patricia A; Bossart, Greg; Carlin, Kevin P; Jensen, Eric D; Smith, Cynthia R; Andrews, Gordon A; Chavey, Patricia S; Venn-Watson, Stephanie

    2012-12-01

    Bottlenose dolphins can have iron overload (that is, hemochromatosis), and managed populations of dolphins may be more susceptible to this disease than are wild dolphins. Serum iron, total iron-binding capacity (TIBC), transferrin saturation, and ferritin were measured in 181 samples from 141 dolphins in 2 managed collections and 2 free-ranging populations. Although no iron indices increased with age among free-ranging dolphins, ferritin increased with age in managed collections. Dolphins from managed collections had higher iron, ferritin, and transferrin saturation values than did free-ranging dolphins. Dolphins with high serum iron (exceeding 300 ?g/dL) were more likely to have elevated ferritin but not ceruloplasmin or haptoglobin, demonstrating that high serum levels of iron are due to a true increase in total body iron. A time-series study of 4 dolphins with hemochromatosis that were treated with phlebotomy demonstrated significant decreases in serum ferritin, iron, and TIBC between pre- and posttreatment samples; transferrin saturation initially fell but returned to prephlebotomy levels by 6 mo after treatment. Compared with those in managed collections, wild dolphins were 15 times more likely to have low serum iron (100 ?g/dL or less), and this measure was associated with lower haptoglobin. In conclusion, bottlenose dolphins in managed collections are more likely to have greater iron stores than are free-ranging dolphins. Determining why this situation occurs among some dolphin populations and not others may improve the treatment of hemochromatosis in dolphins and provide clues to causes of nonhereditary hemochromatosis in humans. PMID:23561885

  7. Plant mechanisms of siderophore-iron utilization

    SciTech Connect

    Crowley, D.E.

    1986-01-01

    Mechanisms of siderophore iron-utilization by plants were examined to determine whether plants have direct mechanisms for acquiring iron from microbially-produced hydroxamate siderophores or simply take up inorganic iron in equilibrium with the chelate (shuttle mechanism). Experiments were designed to determine whether the monocot plant species, oat (Avena sativa L. cv. Victory) could acquire iron from ferrichrome under hydroponic conditions in which iron uptake was most likely to occur by direct use of the chelating agent. Ten-day-old iron-deficient seedlings, grown in aerated Hoagland's nutrient solution (minus iron) buffered at pH 7.4 with CaCO/sub 3/, were placed in fresh nutrient solution containing 10/sup -7.4/M radioactive /sup 55/FeCl/sub 3/ (23.7 mCi/mg) with the synthetic chelate, EDDHA (10..pi../sup 5/M), ferrichrome (10/sup -5/M), or with no chelate. After 6 days, shoot content of /sup 55/Fe in shoots of plants provided with ferrichrome was 100-fold greater than that in shoots of plants provided with EDDHA. Therefore iron uptake by oat under these conditions not only indicates direct use of ferrichrome, but also suggest that oat may be better able to acquire iron from siderophores than from synthetic chelates. One possible mechanism for direct use of chelating agents, may involve siderophore binding sites on the plasmalemma of root cortical cells where iron is split from the chelate by enzymatic reduction of ferric to ferrous iron. To demonstrate hypothesized siderophore binding sites on oat roots, experiments examined possible competition for presumed siderophore binding sites by an inert analog of ferrichrome constructed by irreversible chelation with chromium.

  8. Investigation of Conventional- and Induction-Sintered Iron and Iron-Based Powder Metal Compacts

    NASA Astrophysics Data System (ADS)

    Çavdar, U?ur; Atik, Enver

    2014-06-01

    Induction sintering was developed as an alternative method to conventional sintering to sinter iron-based powder metal (PM) compacts. Several compositions of compact such as pure iron, 3 wt.% copper mixed iron, or 3 wt.% bronze mixed iron were sintered by using induction sintering machines with 12 kW power and 30 kHz frequency. The mechanical properties, microstructural properties, densities, and microhardness values were investigated for both processes. Iron-based PM compacts sintered at 1120°C by induction in 8.33 min (500 s) were found to be similar to those sintered conventionally in 30 min. The results were compared with the experimental studies.

  9. Lacoferrin in rabbit bile: its relation to iron metabolism.

    PubMed

    van Vugt, H; van Gool, J; Ladiges, N C; Boers, W

    1975-04-01

    The relation of biliary lactoferrin concentration and the iron status of the body was studied in normal, anaemic and iron-loaded rabbits. In anaemic rabbits lactoferrin concentrations rose to two to three times the original values. Loading with iron resulted in a return to normal values. Mobilization of iron with desferrioxamine also gave a rise in lactoferrin concentration in bile. Lactoferrin may have a regulatory function in situations of enhanced iron absorption or mobilization of iron from depots. PMID:1040938

  10. Role of hepcidin in murine brain iron metabolism

    Microsoft Academic Search

    S.-M. Wang; L.-J. Fu; X.-L. Duan; D. R. Crooks; P. Yu; Z.-M. Qian; X.-J. Di; J. Li; T. A. Rouault; Y.-Z. Chang

    2010-01-01

    Brain iron homeostasis is maintained by a balance of both iron uptake and release, and accumulating evidence has revealed\\u000a that brain iron concentrations increase with aging. Hepcidin, an iron regulatory hormone produced by hepatocytes in response\\u000a to inflammatory stimuli, iron, and hypoxia, has been shown to be the long-sought hormone responsible for the regulation of\\u000a body iron balance and recycling

  11. Pathogenesis and Management of Iron Overload in MDS

    Microsoft Academic Search

    Chaim Hershko

    \\u000a Iron overload in MDS is the joint outcome of multiple blood transfusions and inappropriately increased iron absorption associated\\u000a with ineffective erythropoiesis. Experience gained in hereditary iron-loading anemias indicates that the long-term consequences\\u000a of iron toxicity are preventable and reversible by effective iron chelation therapy (ICT). With the introduction of orally\\u000a effective iron chelators that are easy to take and suitable

  12. Iron homeostasis in insects: Insights from Drosophila studies.

    PubMed

    Tang, Xiaona; Zhou, Bing

    2013-10-01

    Iron is essential for the survival of almost all organisms. Our current understanding of iron metabolism in different organisms suggests it is a partially conserved but not identical process. Many aspects of iron metabolism in insects remain poorly understood. This review summarizes what we know so far about insect iron homeostasis, including dietary iron absorption, iron transport and storage, as well as homeostasis regulation. New findings made in the model organism Drosophila are emphasized and their implications discussed. PMID:24078394

  13. Iron regulatory protein 1 outcompetes iron regulatory protein 2 in regulating cellular iron homeostasis in response to nitric oxide.

    PubMed

    Sty?, Agnieszka; Galy, Bruno; Starzy?ski, Rafal R; Smuda, Ewa; Drapier, Jean-Claude; Lipi?ski, Pawel; Bouton, Cécile

    2011-07-01

    In mammals, iron regulatory proteins (IRPs) 1 and 2 posttranscriptionally regulate expression of genes involved in iron metabolism, including transferrin receptor 1, the ferritin (Ft) H and L subunits, and ferroportin by binding mRNA motifs called iron responsive elements (IREs). IRP1 is a bifunctional protein that mostly exists in a non-IRE-binding, [4Fe-4S] cluster aconitase form, whereas IRP2, which does not assemble an Fe-S cluster, spontaneously binds IREs. Although both IRPs fulfill a trans-regulatory function, only mice lacking IRP2 misregulate iron metabolism. NO stimulates the IRE-binding activity of IRP1 by targeting its Fe-S cluster. IRP2 has also been reported to sense NO, but the intrinsic function of IRP1 and IRP2 in NO-mediated regulation of cellular iron metabolism is controversial. In this study, we exposed bone marrow macrophages from Irp1(-/-) and Irp2(-/-) mice to NO and showed that the generated apo-IRP1 was entirely responsible for the posttranscriptional regulation of transferrin receptor 1, H-Ft, L-Ft, and ferroportin. The powerful action of NO on IRP1 also remedies the defects of iron storage found in IRP2-null bone marrow macrophages by efficiently reducing Ft overexpression. We also found that NO-dependent IRP1 activation, resulting in increased iron uptake and reduced iron sequestration and export, maintains enough intracellular iron to fuel the Fe-S cluster biosynthetic pathway for efficient restoration of the citric acid cycle aconitase in mitochondria. Thus, IRP1 is the dominant sensor and transducer of NO for posttranscriptional regulation of iron metabolism and participates in Fe-S cluster repair after exposure to NO. PMID:21566147

  14. THE TISHOMINGO IRON: RELATIONSHIP TO IVB IRONS, CR CLAN CHONDRITES AND ANGRITES AND IMPLICATIONS FOR THE ORIGIN OF VOLATILE-DEPLETED IRON

    E-print Network

    Mcdonough, William F.

    THE TISHOMINGO IRON: RELATIONSHIP TO IVB IRONS, CR CLAN CHONDRITES AND ANGRITES AND IMPLICATIONS FOR THE ORIGIN OF VOLATILE-DEPLETED IRON METEORITES. C.M. Corrigan1 , D. Rumble III2 , T.J. McCoy1 , R.D. Ash3 of Maryland, College Park, MD 20742 USA. Introduction: Of the ~1,000 known iron meteor- ites, ~85% fall

  15. Potentiation of iron accumulation in cardiac myocytes during the treatment of iron overload in gerbils with the hydroxypyridinone iron chelator CP94

    Microsoft Academic Search

    P. Carthew; A. G. Smith; R. C. Hider; B. Dorman; R. E. Edwards; J. E. Francis

    1994-01-01

    Gerbils administered iron dextran are the only animal species which have been shown to develop hemochromatosis of the liver and heart in the same manner as transfusion dependent homozygous thalassemics. The iron chelating hydroxypyridinone, CP94, has been administered prophylactically to iron overloaded gerbils in a dosing regime which favors the formation of bidentate chelated iron, to examine the possibility of

  16. Preliminary Iron Distribution on Vesta

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, David W.; Mittlefehldt, David W.

    2013-01-01

    The distribution of iron on the surface of the asteroid Vesta was investigated using Dawn's Gamma Ray and Neutron Detector (GRaND) [1,2]. Iron varies predictably with rock type for the howardite, eucrite, and diogenite (HED) meteorites, thought to be representative of Vesta. The abundance of Fe in howardites ranges from about 12 to 15 wt.%. Basaltic eucrites have the highest abundance, whereas, lower crustal and upper mantle materials (cumulate eucrites and diogenites) have the lowest, and howardites are intermediate [3]. We have completed a mapping study of 7.6 MeV gamma rays produced by neutron capture by Fe as measured by the bismuth germanate (BGO) detector of GRaND [1]. The procedures to determine Fe counting rates are presented in detail here, along with a preliminary distribution map, constituting the necessary initial step to quantification of Fe abundances. We find that the global distribution of Fe counting rates is generally consistent with independent mineralogical and compositional inferences obtained by other instruments on Dawn such as measurements of pyroxene absorption bands by the Visual and Infrared Spectrometer (VIR) [4] and Framing Camera (FC) [5] and neutron absorption measurements by GRaND [6].

  17. Cytosolic Monothiol Glutaredoxins Function in Intracellular Iron Sensing and Trafficking via Their Bound Iron-Sulfur Cluster

    E-print Network

    Mühlenhoff, Ulrich

    Iron is an essential nutrient for cells. It is unknown how iron, after its import into the cytosol, is specifically delivered to iron-dependent processes in various cellular compartments. Here, we identify an essential ...

  18. Molecular mechanisms of iron uptake in fungi

    Microsoft Academic Search

    Daniel J. Kosman

    2003-01-01

    Summary Fungi, like all free-living organisms, are in competi- tion for limiting nutrients. In accumulating iron, fungi are faced also with a trace metal whose aqueous and redox chemistry make it both relatively bio-unavail- able and strongly cytotoxic. Successful adaptation to this environmental context has provided fungi with an iron uptake strategy that has three features: it relies on redox

  19. The Corrosion and Preservation of Iron Antiques.

    ERIC Educational Resources Information Center

    Walker, Robert

    1982-01-01

    Discusses general corrosion reactions (iron to rust), including corrosion of iron, sulfur dioxide, chlorides, immersed corrosion, and underground corrosion. Also discusses corrosion inhibition, including corrosion inhibitors (anodic, cathodic, mixed, organic); safe/dangerous inhibitors; and corrosion/inhibition in concrete/marble, showcases/boxes,…

  20. ARSENIC REMOVAL BY IRON REMOVAL PROCESSES

    EPA Science Inventory

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

  1. Drinking Water Problems: Iron and Manganese 

    E-print Network

    Dozier, Monty; McFarland, Mark L.

    2004-02-20

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

  2. Iron deficiency: from diagnosis to treatment.

    PubMed

    Polin, Vanessa; Coriat, Romain; Perkins, Géraldine; Dhooge, Marion; Abitbol, Vered; Leblanc, Sarah; Prat, Frédéric; Chaussade, Stanislas

    2013-10-01

    Iron deficiency is the most frequent cause of anaemia worldwide. It impairs quality of life, increases asthenia and can lead to clinical worsening of patients. In addition, iron deficiency has a complex mechanism whose pathologic pathway is recently becoming better understood. The discovery of hepcidin has allowed a better clarification of iron metabolism regulation. Furthermore, the ratio of concentration of soluble transferrin receptor to the log of the ferritin level, has been developed as a tool to detect iron deficiency in most situations. The cause of iron deficiency should always be sought because the underlying condition can be serious. This review will summarize the current knowledge regarding diagnostic algorithms for iron deficiency anaemia. The majority of aetiologies occur in the digestive tract, in men and postmenopausal women, and justify morphological examination of the gut. First line investigations are upper gastrointestinal endoscopy and colonoscopy, and when negative, the small bowel should be explored; newer tools such as video capsule endoscopy have also been developed. The treatment of iron deficiency is aetiological if possible and iron supplementation whether in oral or in parenteral form. New parenteral formulations are available and seem to have promising results in terms of efficacy and safety. PMID:23582772

  3. Antibiotic activity of iron-sequestering polymers.

    PubMed

    El-Gendy, Nashwa; Qian, Jian; Eshelman, Kate; Rivera, Mario; Berkland, Cory

    2015-05-11

    Increasing antibiotic resistance has compelled the development of novel antibiotics and adjuvant therapies that enhance the efficacy of existing antibiotics. Iron plays a critical role in bacterial infections, yet the use of iron chelators as adjuvant therapy with antibiotics has yielded highly variable outcomes. Multivalent polymeric materials offer an alternative approach to bind and sequester iron via high avidity interactions. Here, a biomimetic iron-sequestering polymer (PAI-DHBA) was synthesized by modifying side chains of cross-linked polyallylamine (cPAI) with 2,3-dihydroxybenzoic acid (DHBA). PAI-DHBA polymer gels with various DHBA contents showed high iron affinity indices and high selectivity for iron. The polymers showed mild antibiotic properties when used to treat established bacterial cultures. Pretreating culture media with PAI-DHBA polymer, however, removed all detectable iron from media and effectively inhibited the growth of Pseudomonas aeruginosa. In addition, bacterial growth was more susceptible to antibiotics combined with PAI-DHBA. Multivalent polymers that bind and sequester iron, such as PAI-DHBA, offer a promising early intervention or adjuvant to antibiotics. PMID:25872681

  4. The Iron abundance in Galactic Planetary Nebulae

    E-print Network

    G. Delgado-Inglada; M. Rodriguez; A. Mampaso; K. Viironen

    2009-03-31

    We constrain the iron abundance in a sample of 33 low-ionization Galactic planetary nebulae (PNe) using [Fe III] lines and correcting for the contribution of higher ionization states with ionization correction factors (ICFs) that take into account uncertainties in the atomic data. We find very low iron abundances in all the objects, suggesting that more than 90% of their iron atoms are condensed onto dust grains. This number is based on the solar iron abundance and implies a lower limit on the dust-to-gas mass ratio, due solely to iron, of M_dust/M_gas>1.3x10^{-3} for our sample. The depletion factors of different PNe cover about two orders of magnitude, probably reflecting differences in the formation, growth, or destruction of their dust grains. However, we do not find any systematic difference between the gaseous iron abundances calculated for C-rich and O-rich PNe, suggesting similar iron depletion efficiencies in both environments. The iron abundances of our sample PNe are similar to those derived following the same procedure for a group of 10 Galactic H II regions. These high depletion factors argue for high depletion efficiencies of refractory elements onto dust grains both in molecular clouds and AGB stars, and low dust destruction efficiencies both in interstellar and circumstellar ionized gas.

  5. Formation and Reactivity of Biogenic Iron Microminerals

    SciTech Connect

    Beveridge, Terrance J.; Ferris, F. Grant

    2001-08-15

    The overall purpose of the project was to explore and quantify the processes that control the formation and reactivity of biogenic iron microminerals and their impact on the solubility of metal contaminants. The research addressed how surface components of bacterial cells, extracellular organic material, and the aqueous geochemistry of the DIRB microenvironment impacts the mineralogy, chemical state and micromorphology of reduced iron phases.

  6. The iron horse: a sound ride

    Microsoft Academic Search

    Hanna Landin; Sus Lundgren; Johannes Prison

    2002-01-01

    The Iron Horse combines modern technology with a childhood dream. It's a bike --- but its sounds like a horse. By biking at different speeds, one can get it to walk, trot or gallop. Sometimes it snorts, and it greets its owner and other iron horses with a neigh. In the project, we explored how to transfer the auditive expressions

  7. Nickel-iron spherules from aouelloul glass

    USGS Publications Warehouse

    Chao, E.C.T.; Dwornik, E.J.; Merrill, C.W.

    1966-01-01

    Nickel-iron spherules, ranging from less than 0.2 to 50 microns in diameter and containing 1.7 to 9.0 percent Ni by weight, occur in glass associated with the Aouelloul crater. They occur in discrete bands of siliceous glass enriched in dissolved iron. Their discovery is significant tangible evidence that both crater and glass originated from terrestrial impact.

  8. Iron-catalyzed asymmetric hydrosilylation of ketones.

    PubMed

    Zuo, Ziqing; Zhang, Lei; Leng, Xuebing; Huang, Zheng

    2015-03-25

    A series of iron complexes of chiral iminopyridine-oxazoline (IPO) ligands have been synthesized. The most sterically hindered iron catalyst exhibits excellent activity (up to 99% yield) and high enantioselectivity (up to 93% ee) in asymmetric hydrosilylation of aryl ketones. PMID:25712676

  9. Enhancing the Absorption of Fortification Iron

    Microsoft Academic Search

    Richard F. Hurrell; Sean Lynch; Thomas Bothwell; Héctor Cori; Ray Glahn; Eva Hertrampf; Zdenek Kratky; Dennis Miller; Mario Rodenstein; Hugo Streekstra; Birgit Teucher; Elizabeth Turner; C. K. Yeung; Michael B. Zimmermann

    2004-01-01

    Iron deficiency remains a major global health problem affecting an estimated 2 billion people (1). The World Health Organization ranked it as the seventh most important preventable risk for disease, disability, and death in 2002 (2). Since an important factor in its causation is the poor bioavailability of iron in the cereal-based diets of many developing countries, SUSTAIN set up

  10. Related Formation of IIIE and IIIAB Irons

    NASA Astrophysics Data System (ADS)

    Wasson, J. T.

    2013-09-01

    The magmatic iron meteorites from group IIIE have compositions closely similar to those in IIIAB, the largest group of irons. The groups are fully resolved on some element-Au diagrams. The chief difference seems to be the higher C content of IIIE.

  11. Hepcidin and Iron Homeostasis during Pregnancy

    PubMed Central

    Koenig, Mary Dawn; Tussing-Humphreys, Lisa; Day, Jessica; Cadwell, Brooke; Nemeth, Elizabeta

    2014-01-01

    Hepcidin is the master regulator of systemic iron bioavailability in humans. This review examines primary research articles that assessed hepcidin during pregnancy and postpartum and report its relationship to maternal and infant iron status and birth outcomes; areas for future research are also discussed. A systematic search of the databases Medline and Cumulative Index to Nursing and Allied Health returned 16 primary research articles including 10 human and six animal studies. Collectively, the results indicate that hepcidin is lower during pregnancy than in a non-pregnant state, presumably to ensure greater iron bioavailability to the mother and fetus. Pregnant women with undetectable serum hepcidin transferred a greater quantity of maternally ingested iron to their fetus compared to women with detectable hepcidin, indicating that maternal hepcidin in part determines the iron bioavailability to the fetus. However, inflammatory states, including preeclampsia, malaria infection, and obesity were associated with higher hepcidin during pregnancy compared to healthy controls, suggesting that maternal and fetal iron bioavailability could be compromised in such conditions. Future studies should examine the relative contribution of maternal versus fetal hepcidin to the control of placental iron transfer as well as optimizing maternal and fetal iron bioavailability in pregnancies complicated by inflammation. PMID:25093277

  12. Removal of metallic iron on oxide slags

    SciTech Connect

    Shannon, G.N.; Fruehan, R.J.; Sridhar, S. [Carnegie Mellon University, Pittsburgh, PA (United States). Dept. of Material Science & Engineering

    2009-10-15

    It is possible, in some cases, for ground coal particles to react with gasifier gas during combustion, allowing the ash material in the coal to form phases besides the expected slag phase. One of these phases is metallic iron, because some gasifiers are designed to operate under a reducing atmosphere (pO{sub 2}) of approximately 10{sup -4} atm). Metallic iron can become entrained in the gas stream and deposit on, and foul, downstream equipment. To improve the understanding of the reaction between different metallic iron particles and gas, which eventually oxidizes them, and the slag that the resulting oxide dissolves in, the kinetics of iron reaction on slag were predicted using gas-phase mass-transfer limitations for the reaction and were compared with diffusion in the slag; the reaction itself was observed under confocal scanning laser microscopy. The expected rates for iron droplet removal are provided based on the size and effective partial pressure of oxygen, and it is found that decarburization occurs before iron reaction, leading to an extra 30- to 100-second delay for carbon-saturated particles vs pure iron particles. A pure metallic iron particle of 0.5 mg should be removed in about 220 seconds at 1400{sup o}C and in 160 seconds at 1600{sup o}C.

  13. Dechlorination of TCE with palladized iron

    DOEpatents

    Fernando, Quintus (Tucson, AZ); Muftikian, Rosy (Tucson, AZ); Korte, Nic (Grand Junction, CO)

    1997-01-01

    The present invention relates to various methods, such as an above-ground method and an in-ground method, of using a palladized iron bimetallic system for the dechlorination of chlorinated organic compounds from various effluents or contaminated soil containing the same. The use of palladized iron bimetallic system results in the dechlorination of the chlorinated organic compound into environmentally safe reaction products.

  14. Iron and Steel- Properties and Applications

    NSDL National Science Digital Library

    Stoebe, Thomas G.

    This document provides a learning module on iron and steel for use in materials education. The lesson examines the basic properties of iron and steel and includes discussions, demonstrations and suggested optional classroom activities. The materials can be covered in one to two class periods.

  15. Developing Standards for Dissolved Iron in Seawater

    Microsoft Academic Search

    Kenneth S. Johnson; Edward Boyle; Kenneth Bruland; Kenneth Coale; Chris Measures; James Moffett; Ana Aguilar-Islas; Katherine Barbeau; Bridget Bergquist; Andrew Bowie; Kristen Buck; Yihua Cai; Zanna Chase; Jay Cullen; Takashi Doi; Virginia Elrod; Steve Fitzwater; Michael Gordon; Andrew King; Patrick Laan; Luis Laglera-Baquer; William Landing; Maeve Lohan; Jeffrey Mendez; Angela Milne; Hajime Obata; Lia Ossiander; Joshua Plant; Geraldine Sarthou; Peter Sedwick; Geoffrey J. Smith; Bettina Sohst; Sara Tanner; Stan Van den Berg; Jingfeng Wu

    2007-01-01

    In nearly a dozen open-ocean fertilization experiments conducted by more than 100 researchers from nearly 20 countries, adding iron at the sea surface has led to distinct increases in photosynthesis rates and biomass. These experiments confirmed the hypothesis proposed by the late John Martin that dissolved iron concentration is a key variable that controls phytoplankton processes in ocean surface waters.

  16. Production of iron from metallurgical waste

    DOEpatents

    Hendrickson, David W; Iwasaki, Iwao

    2013-09-17

    A method of recovering metallic iron from iron-bearing metallurgical waste in steelmaking comprising steps of providing an iron-bearing metallurgical waste containing more than 55% by weight FeO and FeO equivalent and a particle size of at least 80% less than 10 mesh, mixing the iron-bearing metallurgical waste with a carbonaceous material to form a reducible mixture where the carbonaceous material is between 80 and 110% of the stoichiometric amount needed to reduce the iron-bearing waste to metallic iron, and as needed additions to provide a silica content between 0.8 and 8% by weight and a ratio of CaO/SiO.sub.2 between 1.4 and 1.8, forming agglomerates of the reducible mixture over a hearth material layer to protect the hearth, heating the agglomerates to a higher temperature above the melting point of iron to form nodules of metallic iron and slag material from the agglomerates by melting.

  17. Ferritin iron minerals are chelator targets, antioxidants, and coated, dietary iron

    PubMed Central

    Theil, Elizabeth C.

    2012-01-01

    Cellular ferritin is central for iron balance during transfusions therapies; serum ferritin is a small fraction of body ferritin, albeit a convenient reporter. Iron overload induces extra ferritin protein synthesis but the protein is overfilled with the extra iron that damages ferritin, with conversion to toxic hemosiderin. Three new approaches that manipulate ferritin to address excess iron, hemosiderin, and associated oxidative damage in Cooley’s Anemia and other iron overload conditions, are faster removal of ferritin iron with chelators guided to ferritin gated pores by peptides; more ferritin protein synthesis using ferritin mRNA activators, by metal complexes that target mRNA 3D structures; and determining if endocytotic absorption of iron from legumes, which is mostly ferritin, is regulated during iron overload to prevent excess iron entry while providing protein. More of a focus on ferritin features, including protein cage structure, iron mineral, regulatable mRNA, and specific gut absorption properties, will achieve the three novel experimental goals for managing iron homeostasis with transfusion therapies. PMID:20712793

  18. Impact of iron overload and potential benefit from iron chelation in low-risk myelodysplastic syndrome.

    PubMed

    Shenoy, Niraj; Vallumsetla, Nishanth; Rachmilewitz, Eliezer; Verma, Amit; Ginzburg, Yelena

    2014-08-01

    Myelodysplastic syndromes (MDSs) are a group of heterogeneous clonal bone marrow disorders characterized by ineffective hematopoiesis, peripheral blood cytopenias, and potential for malignant transformation. Lower/intermediate-risk MDSs are associated with longer survival and high red blood cell (RBC) transfusion requirements resulting in secondary iron overload. Recent data suggest that markers of iron overload portend a relatively poor prognosis, and retrospective analysis demonstrates that iron chelation therapy is associated with prolonged survival in transfusion-dependent MDS patients. New data provide concrete evidence of iron's adverse effects on erythroid precursors in vitro and in vivo. Renewed interest in the iron field was heralded by the discovery of hepcidin, the main serum peptide hormone negative regulator of body iron. Evidence from ?-thalassemia suggests that regulation of hepcidin by erythropoiesis dominates regulation by iron. Because iron overload develops in some MDS patients who do not require RBC transfusions, the suppressive effect of ineffective erythropoiesis on hepcidin may also play a role in iron overload. We anticipate that additional novel tools for measuring iron overload and a molecular-mechanism-driven description of MDS subtypes will provide a deeper understanding of how iron metabolism and erythropoiesis intersect in MDSs and improve clinical management of this patient population. PMID:24923296

  19. Iron release from haemosiderin and production of iron-catalysed hydroxyl radicals in vitro.

    PubMed Central

    Ozaki, M; Kawabata, T; Awai, M

    1988-01-01

    Isolated haemosiderin contained iron and nitrogen in a weight ratio of 6.75, with phosphorus and no detectable haem. Considerably more iron was released from haemosiderin under acidic conditions than under neutral conditions in the presence of ascorbate, nitrilotriacetate or dithionite. Unlike the situation with ascorbate, chelators such as citrate, ADP or succinate induced the release of only some iron, with almost no pH-dependence. Dehydroascorbate (the oxidized form of ascorbate with no reducing capacity) behaved like citrate, ADP, succinate or desferal, rather than like ascorbate itself, in releasing iron. GSH had less effect on the release of iron than these chelators, but in the presence of a small amount of chelator the release of iron increased, especially under acidic conditions. Thus reduction, chelation and pH were all found to be important factors involved in the release of iron from haemosiderin. Investigation by e.p.r. of hydroxyl-radical production by the released iron showed high radical productivity at an acidic pH. However, at a physiological pH, almost no radical formation was detected, except in the presence of nitrilotriacetate. These findings suggested that, under physiological conditions, haemosiderin was not an effective iron donor and was almost not involved in radical production. Under acidic conditions, however, such as in inflammation, hypoxia and in a lysosomal milieu, it could possibly be an iron donor and is thought to be implicated in radical production and tissue damage in iron-overloaded conditions. Images Fig. 1. PMID:2833249

  20. The tongue and oesophagus in iron-deficiency anaemia and the effect of iron therapy

    PubMed Central

    Baird, I. McLean; Dodge, O. G.; Palmer, F. J.; Wawman, R. J.

    1961-01-01

    Biopsies of the tongue and oesophagus were performed on 14 patients with uncomplicated iron-deficiency anaemia before and after treatment with iron. Haemoglobin and serum iron estimations were performed at the same time. Nine patients had clinical evidence of atrophic changes in the tongue before therapy was started. Evidence of regeneration appeared within one or two weeks of starting iron therapy. Two patients showed persistent atrophy. Angular stomatitis and koilonychia were longer in disappearing. Biopsies confirmed that filiform papillae and kerato-hyalin granules are frequently absent from the epithelium of the smooth tongues of iron-deficient patients. Iron therapy is followed by the re-appearance of keratohyalin granules and keratinized filiform papillae. Two patients complained of dysphagia, which disappeared after treatment. No abnormality in the oesophageal epithelium was found in any of the patients either before or after therapy. The relationship of oesophageal carcinoma to antecedent iron-deficiency epithelial changes is considered suspect. Images PMID:13864068